diff options
Diffstat (limited to 'tools/lib/bpf')
33 files changed, 24927 insertions, 0 deletions
diff --git a/tools/lib/bpf/.gitignore b/tools/lib/bpf/.gitignore new file mode 100644 index 000000000..8a81b3679 --- /dev/null +++ b/tools/lib/bpf/.gitignore @@ -0,0 +1,9 @@ +# SPDX-License-Identifier: GPL-2.0-only +libbpf_version.h +libbpf.pc +FEATURE-DUMP.libbpf +libbpf.so.* +TAGS +tags +cscope.* +/bpf_helper_defs.h diff --git a/tools/lib/bpf/Build b/tools/lib/bpf/Build new file mode 100644 index 000000000..190366d05 --- /dev/null +++ b/tools/lib/bpf/Build @@ -0,0 +1,3 @@ +libbpf-y := libbpf.o bpf.o nlattr.o btf.o libbpf_errno.o str_error.o \ + netlink.o bpf_prog_linfo.o libbpf_probes.o xsk.o hashmap.o \ + btf_dump.o ringbuf.o diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile new file mode 100644 index 000000000..f2a353bba --- /dev/null +++ b/tools/lib/bpf/Makefile @@ -0,0 +1,308 @@ +# SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) +# Most of this file is copied from tools/lib/traceevent/Makefile + +RM ?= rm +srctree = $(abs_srctree) + +VERSION_SCRIPT := libbpf.map +LIBBPF_VERSION := $(shell \ + grep -oE '^LIBBPF_([0-9.]+)' $(VERSION_SCRIPT) | \ + sort -rV | head -n1 | cut -d'_' -f2) +LIBBPF_MAJOR_VERSION := $(firstword $(subst ., ,$(LIBBPF_VERSION))) + +MAKEFLAGS += --no-print-directory + +# This will work when bpf is built in tools env. where srctree +# isn't set and when invoked from selftests build, where srctree +# is a ".". building_out_of_srctree is undefined for in srctree +# builds +ifndef building_out_of_srctree +srctree := $(patsubst %/,%,$(dir $(CURDIR))) +srctree := $(patsubst %/,%,$(dir $(srctree))) +srctree := $(patsubst %/,%,$(dir $(srctree))) +#$(info Determined 'srctree' to be $(srctree)) +endif + +INSTALL = install + +# Use DESTDIR for installing into a different root directory. +# This is useful for building a package. The program will be +# installed in this directory as if it was the root directory. +# Then the build tool can move it later. +DESTDIR ?= +DESTDIR_SQ = '$(subst ','\'',$(DESTDIR))' + +include $(srctree)/tools/scripts/Makefile.arch + +ifeq ($(LP64), 1) + libdir_relative = lib64 +else + libdir_relative = lib +endif + +prefix ?= /usr/local +libdir = $(prefix)/$(libdir_relative) +man_dir = $(prefix)/share/man +man_dir_SQ = '$(subst ','\'',$(man_dir))' + +export man_dir man_dir_SQ INSTALL +export DESTDIR DESTDIR_SQ + +include $(srctree)/tools/scripts/Makefile.include + +# copy a bit from Linux kbuild + +ifeq ("$(origin V)", "command line") + VERBOSE = $(V) +endif +ifndef VERBOSE + VERBOSE = 0 +endif + +FEATURE_USER = .libbpf +FEATURE_TESTS = libelf zlib bpf +FEATURE_DISPLAY = libelf zlib bpf + +INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/tools/include/uapi +FEATURE_CHECK_CFLAGS-bpf = $(INCLUDES) + +check_feat := 1 +NON_CHECK_FEAT_TARGETS := clean TAGS tags cscope help +ifdef MAKECMDGOALS +ifeq ($(filter-out $(NON_CHECK_FEAT_TARGETS),$(MAKECMDGOALS)),) + check_feat := 0 +endif +endif + +ifeq ($(check_feat),1) +ifeq ($(FEATURES_DUMP),) +include $(srctree)/tools/build/Makefile.feature +else +include $(FEATURES_DUMP) +endif +endif + +export prefix libdir src obj + +# Shell quotes +libdir_SQ = $(subst ','\'',$(libdir)) +libdir_relative_SQ = $(subst ','\'',$(libdir_relative)) + +OBJ = $@ +N = + +LIB_TARGET = libbpf.a libbpf.so.$(LIBBPF_VERSION) +LIB_FILE = libbpf.a libbpf.so* +PC_FILE = libbpf.pc + +# Set compile option CFLAGS +ifdef EXTRA_CFLAGS + CFLAGS := $(EXTRA_CFLAGS) +else + CFLAGS := -g -O2 +endif + +# Append required CFLAGS +override CFLAGS += $(EXTRA_WARNINGS) -Wno-switch-enum +override CFLAGS += -Werror -Wall +override CFLAGS += $(INCLUDES) +override CFLAGS += -fvisibility=hidden +override CFLAGS += -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 + +# flags specific for shared library +SHLIB_FLAGS := -DSHARED -fPIC + +ifeq ($(VERBOSE),1) + Q = +else + Q = @ +endif + +# Disable command line variables (CFLAGS) override from top +# level Makefile (perf), otherwise build Makefile will get +# the same command line setup. +MAKEOVERRIDES= + +all: + +export srctree OUTPUT CC LD CFLAGS V +include $(srctree)/tools/build/Makefile.include + +SHARED_OBJDIR := $(OUTPUT)sharedobjs/ +STATIC_OBJDIR := $(OUTPUT)staticobjs/ +BPF_IN_SHARED := $(SHARED_OBJDIR)libbpf-in.o +BPF_IN_STATIC := $(STATIC_OBJDIR)libbpf-in.o +BPF_HELPER_DEFS := $(OUTPUT)bpf_helper_defs.h + +LIB_TARGET := $(addprefix $(OUTPUT),$(LIB_TARGET)) +LIB_FILE := $(addprefix $(OUTPUT),$(LIB_FILE)) +PC_FILE := $(addprefix $(OUTPUT),$(PC_FILE)) + +TAGS_PROG := $(if $(shell which etags 2>/dev/null),etags,ctags) + +GLOBAL_SYM_COUNT = $(shell readelf -s --wide $(BPF_IN_SHARED) | \ + cut -d "@" -f1 | sed 's/_v[0-9]_[0-9]_[0-9].*//' | \ + sed 's/\[.*\]//' | \ + awk '/GLOBAL/ && /DEFAULT/ && !/UND/ {print $$NF}' | \ + sort -u | wc -l) +VERSIONED_SYM_COUNT = $(shell readelf --dyn-syms --wide $(OUTPUT)libbpf.so | \ + sed 's/\[.*\]//' | \ + awk '/GLOBAL/ && /DEFAULT/ && !/UND|ABS/ {print $$NF}' | \ + grep -Eo '[^ ]+@LIBBPF_' | cut -d@ -f1 | sort -u | wc -l) + +CMD_TARGETS = $(LIB_TARGET) $(PC_FILE) + +all: fixdep + $(Q)$(MAKE) all_cmd + +all_cmd: $(CMD_TARGETS) check + +$(BPF_IN_SHARED): force elfdep zdep bpfdep $(BPF_HELPER_DEFS) + @(test -f ../../include/uapi/linux/bpf.h -a -f ../../../include/uapi/linux/bpf.h && ( \ + (diff -B ../../include/uapi/linux/bpf.h ../../../include/uapi/linux/bpf.h >/dev/null) || \ + echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/bpf.h' differs from latest version at 'include/uapi/linux/bpf.h'" >&2 )) || true + @(test -f ../../include/uapi/linux/bpf_common.h -a -f ../../../include/uapi/linux/bpf_common.h && ( \ + (diff -B ../../include/uapi/linux/bpf_common.h ../../../include/uapi/linux/bpf_common.h >/dev/null) || \ + echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/bpf_common.h' differs from latest version at 'include/uapi/linux/bpf_common.h'" >&2 )) || true + @(test -f ../../include/uapi/linux/netlink.h -a -f ../../../include/uapi/linux/netlink.h && ( \ + (diff -B ../../include/uapi/linux/netlink.h ../../../include/uapi/linux/netlink.h >/dev/null) || \ + echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/netlink.h' differs from latest version at 'include/uapi/linux/netlink.h'" >&2 )) || true + @(test -f ../../include/uapi/linux/if_link.h -a -f ../../../include/uapi/linux/if_link.h && ( \ + (diff -B ../../include/uapi/linux/if_link.h ../../../include/uapi/linux/if_link.h >/dev/null) || \ + echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/if_link.h' differs from latest version at 'include/uapi/linux/if_link.h'" >&2 )) || true + @(test -f ../../include/uapi/linux/if_xdp.h -a -f ../../../include/uapi/linux/if_xdp.h && ( \ + (diff -B ../../include/uapi/linux/if_xdp.h ../../../include/uapi/linux/if_xdp.h >/dev/null) || \ + echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/if_xdp.h' differs from latest version at 'include/uapi/linux/if_xdp.h'" >&2 )) || true + $(Q)$(MAKE) $(build)=libbpf OUTPUT=$(SHARED_OBJDIR) CFLAGS="$(CFLAGS) $(SHLIB_FLAGS)" + +$(BPF_IN_STATIC): force elfdep zdep bpfdep $(BPF_HELPER_DEFS) + $(Q)$(MAKE) $(build)=libbpf OUTPUT=$(STATIC_OBJDIR) + +$(BPF_HELPER_DEFS): $(srctree)/tools/include/uapi/linux/bpf.h + $(QUIET_GEN)$(srctree)/scripts/bpf_helpers_doc.py --header \ + --file $(srctree)/tools/include/uapi/linux/bpf.h > $(BPF_HELPER_DEFS) + +$(OUTPUT)libbpf.so: $(OUTPUT)libbpf.so.$(LIBBPF_VERSION) + +$(OUTPUT)libbpf.so.$(LIBBPF_VERSION): $(BPF_IN_SHARED) $(VERSION_SCRIPT) + $(QUIET_LINK)$(CC) $(LDFLAGS) \ + --shared -Wl,-soname,libbpf.so.$(LIBBPF_MAJOR_VERSION) \ + -Wl,--version-script=$(VERSION_SCRIPT) $< -lelf -lz -o $@ + @ln -sf $(@F) $(OUTPUT)libbpf.so + @ln -sf $(@F) $(OUTPUT)libbpf.so.$(LIBBPF_MAJOR_VERSION) + +$(OUTPUT)libbpf.a: $(BPF_IN_STATIC) + $(QUIET_LINK)$(RM) -f $@; $(AR) rcs $@ $^ + +$(OUTPUT)libbpf.pc: + $(QUIET_GEN)sed -e "s|@PREFIX@|$(prefix)|" \ + -e "s|@LIBDIR@|$(libdir_SQ)|" \ + -e "s|@VERSION@|$(LIBBPF_VERSION)|" \ + < libbpf.pc.template > $@ + +check: check_abi + +check_abi: $(OUTPUT)libbpf.so $(VERSION_SCRIPT) + @if [ "$(GLOBAL_SYM_COUNT)" != "$(VERSIONED_SYM_COUNT)" ]; then \ + echo "Warning: Num of global symbols in $(BPF_IN_SHARED)" \ + "($(GLOBAL_SYM_COUNT)) does NOT match with num of" \ + "versioned symbols in $^ ($(VERSIONED_SYM_COUNT))." \ + "Please make sure all LIBBPF_API symbols are" \ + "versioned in $(VERSION_SCRIPT)." >&2; \ + readelf -s --wide $(BPF_IN_SHARED) | \ + cut -d "@" -f1 | sed 's/_v[0-9]_[0-9]_[0-9].*//' | \ + sed 's/\[.*\]//' | \ + awk '/GLOBAL/ && /DEFAULT/ && !/UND/ {print $$NF}'| \ + sort -u > $(OUTPUT)libbpf_global_syms.tmp; \ + readelf --dyn-syms --wide $(OUTPUT)libbpf.so | \ + sed 's/\[.*\]//' | \ + awk '/GLOBAL/ && /DEFAULT/ && !/UND|ABS/ {print $$NF}'| \ + grep -Eo '[^ ]+@LIBBPF_' | cut -d@ -f1 | \ + sort -u > $(OUTPUT)libbpf_versioned_syms.tmp; \ + diff -u $(OUTPUT)libbpf_global_syms.tmp \ + $(OUTPUT)libbpf_versioned_syms.tmp; \ + rm $(OUTPUT)libbpf_global_syms.tmp \ + $(OUTPUT)libbpf_versioned_syms.tmp; \ + exit 1; \ + fi + +define do_install_mkdir + if [ ! -d '$(DESTDIR_SQ)$1' ]; then \ + $(INSTALL) -d -m 755 '$(DESTDIR_SQ)$1'; \ + fi +endef + +define do_install + if [ ! -d '$(DESTDIR_SQ)$2' ]; then \ + $(INSTALL) -d -m 755 '$(DESTDIR_SQ)$2'; \ + fi; \ + $(INSTALL) $(if $3,-m $3,) $1 '$(DESTDIR_SQ)$2' +endef + +install_lib: all_cmd + $(call QUIET_INSTALL, $(LIB_TARGET)) \ + $(call do_install_mkdir,$(libdir_SQ)); \ + cp -fpR $(LIB_FILE) $(DESTDIR)$(libdir_SQ) + +install_headers: $(BPF_HELPER_DEFS) + $(call QUIET_INSTALL, headers) \ + $(call do_install,bpf.h,$(prefix)/include/bpf,644); \ + $(call do_install,libbpf.h,$(prefix)/include/bpf,644); \ + $(call do_install,btf.h,$(prefix)/include/bpf,644); \ + $(call do_install,libbpf_util.h,$(prefix)/include/bpf,644); \ + $(call do_install,libbpf_common.h,$(prefix)/include/bpf,644); \ + $(call do_install,xsk.h,$(prefix)/include/bpf,644); \ + $(call do_install,bpf_helpers.h,$(prefix)/include/bpf,644); \ + $(call do_install,$(BPF_HELPER_DEFS),$(prefix)/include/bpf,644); \ + $(call do_install,bpf_tracing.h,$(prefix)/include/bpf,644); \ + $(call do_install,bpf_endian.h,$(prefix)/include/bpf,644); \ + $(call do_install,bpf_core_read.h,$(prefix)/include/bpf,644); + +install_pkgconfig: $(PC_FILE) + $(call QUIET_INSTALL, $(PC_FILE)) \ + $(call do_install,$(PC_FILE),$(libdir_SQ)/pkgconfig,644) + +install: install_lib install_pkgconfig install_headers + +### Cleaning rules + +config-clean: + $(call QUIET_CLEAN, feature-detect) + $(Q)$(MAKE) -C $(srctree)/tools/build/feature/ clean >/dev/null + +clean: config-clean + $(call QUIET_CLEAN, libbpf) $(RM) -rf $(CMD_TARGETS) \ + *~ .*.d .*.cmd LIBBPF-CFLAGS $(BPF_HELPER_DEFS) \ + $(SHARED_OBJDIR) $(STATIC_OBJDIR) \ + $(addprefix $(OUTPUT), \ + *.o *.a *.so *.so.$(LIBBPF_MAJOR_VERSION) *.pc) + $(call QUIET_CLEAN, core-gen) $(RM) $(OUTPUT)FEATURE-DUMP.libbpf + + + +PHONY += force elfdep zdep bpfdep cscope tags +force: + +elfdep: + @if [ "$(feature-libelf)" != "1" ]; then echo "No libelf found"; exit 1 ; fi + +zdep: + @if [ "$(feature-zlib)" != "1" ]; then echo "No zlib found"; exit 1 ; fi + +bpfdep: + @if [ "$(feature-bpf)" != "1" ]; then echo "BPF API too old"; exit 1 ; fi + +cscope: + ls *.c *.h > cscope.files + cscope -b -q -I $(srctree)/include -f cscope.out + +tags: + $(RM) -f TAGS tags + ls *.c *.h | xargs $(TAGS_PROG) -a + +# Declare the contents of the .PHONY variable as phony. We keep that +# information in a variable so we can use it in if_changed and friends. +.PHONY: $(PHONY) + +# Delete partially updated (corrupted) files on error +.DELETE_ON_ERROR: diff --git a/tools/lib/bpf/README.rst b/tools/lib/bpf/README.rst new file mode 100644 index 000000000..8928f7787 --- /dev/null +++ b/tools/lib/bpf/README.rst @@ -0,0 +1,168 @@ +.. SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) + +libbpf API naming convention +============================ + +libbpf API provides access to a few logically separated groups of +functions and types. Every group has its own naming convention +described here. It's recommended to follow these conventions whenever a +new function or type is added to keep libbpf API clean and consistent. + +All types and functions provided by libbpf API should have one of the +following prefixes: ``bpf_``, ``btf_``, ``libbpf_``, ``xsk_``, +``perf_buffer_``. + +System call wrappers +-------------------- + +System call wrappers are simple wrappers for commands supported by +sys_bpf system call. These wrappers should go to ``bpf.h`` header file +and map one-on-one to corresponding commands. + +For example ``bpf_map_lookup_elem`` wraps ``BPF_MAP_LOOKUP_ELEM`` +command of sys_bpf, ``bpf_prog_attach`` wraps ``BPF_PROG_ATTACH``, etc. + +Objects +------- + +Another class of types and functions provided by libbpf API is "objects" +and functions to work with them. Objects are high-level abstractions +such as BPF program or BPF map. They're represented by corresponding +structures such as ``struct bpf_object``, ``struct bpf_program``, +``struct bpf_map``, etc. + +Structures are forward declared and access to their fields should be +provided via corresponding getters and setters rather than directly. + +These objects are associated with corresponding parts of ELF object that +contains compiled BPF programs. + +For example ``struct bpf_object`` represents ELF object itself created +from an ELF file or from a buffer, ``struct bpf_program`` represents a +program in ELF object and ``struct bpf_map`` is a map. + +Functions that work with an object have names built from object name, +double underscore and part that describes function purpose. + +For example ``bpf_object__open`` consists of the name of corresponding +object, ``bpf_object``, double underscore and ``open`` that defines the +purpose of the function to open ELF file and create ``bpf_object`` from +it. + +Another example: ``bpf_program__load`` is named for corresponding +object, ``bpf_program``, that is separated from other part of the name +by double underscore. + +All objects and corresponding functions other than BTF related should go +to ``libbpf.h``. BTF types and functions should go to ``btf.h``. + +Auxiliary functions +------------------- + +Auxiliary functions and types that don't fit well in any of categories +described above should have ``libbpf_`` prefix, e.g. +``libbpf_get_error`` or ``libbpf_prog_type_by_name``. + +AF_XDP functions +------------------- + +AF_XDP functions should have an ``xsk_`` prefix, e.g. +``xsk_umem__get_data`` or ``xsk_umem__create``. The interface consists +of both low-level ring access functions and high-level configuration +functions. These can be mixed and matched. Note that these functions +are not reentrant for performance reasons. + +Please take a look at Documentation/networking/af_xdp.rst in the Linux +kernel source tree on how to use XDP sockets and for some common +mistakes in case you do not get any traffic up to user space. + +libbpf ABI +========== + +libbpf can be both linked statically or used as DSO. To avoid possible +conflicts with other libraries an application is linked with, all +non-static libbpf symbols should have one of the prefixes mentioned in +API documentation above. See API naming convention to choose the right +name for a new symbol. + +Symbol visibility +----------------- + +libbpf follow the model when all global symbols have visibility "hidden" +by default and to make a symbol visible it has to be explicitly +attributed with ``LIBBPF_API`` macro. For example: + +.. code-block:: c + + LIBBPF_API int bpf_prog_get_fd_by_id(__u32 id); + +This prevents from accidentally exporting a symbol, that is not supposed +to be a part of ABI what, in turn, improves both libbpf developer- and +user-experiences. + +ABI versionning +--------------- + +To make future ABI extensions possible libbpf ABI is versioned. +Versioning is implemented by ``libbpf.map`` version script that is +passed to linker. + +Version name is ``LIBBPF_`` prefix + three-component numeric version, +starting from ``0.0.1``. + +Every time ABI is being changed, e.g. because a new symbol is added or +semantic of existing symbol is changed, ABI version should be bumped. +This bump in ABI version is at most once per kernel development cycle. + +For example, if current state of ``libbpf.map`` is: + +.. code-block:: + LIBBPF_0.0.1 { + global: + bpf_func_a; + bpf_func_b; + local: + \*; + }; + +, and a new symbol ``bpf_func_c`` is being introduced, then +``libbpf.map`` should be changed like this: + +.. code-block:: + LIBBPF_0.0.1 { + global: + bpf_func_a; + bpf_func_b; + local: + \*; + }; + LIBBPF_0.0.2 { + global: + bpf_func_c; + } LIBBPF_0.0.1; + +, where new version ``LIBBPF_0.0.2`` depends on the previous +``LIBBPF_0.0.1``. + +Format of version script and ways to handle ABI changes, including +incompatible ones, described in details in [1]. + +Stand-alone build +================= + +Under https://github.com/libbpf/libbpf there is a (semi-)automated +mirror of the mainline's version of libbpf for a stand-alone build. + +However, all changes to libbpf's code base must be upstreamed through +the mainline kernel tree. + +License +======= + +libbpf is dual-licensed under LGPL 2.1 and BSD 2-Clause. + +Links +===== + +[1] https://www.akkadia.org/drepper/dsohowto.pdf + (Chapter 3. Maintaining APIs and ABIs). diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c new file mode 100644 index 000000000..d27e34133 --- /dev/null +++ b/tools/lib/bpf/bpf.c @@ -0,0 +1,933 @@ +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) + +/* + * common eBPF ELF operations. + * + * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org> + * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com> + * Copyright (C) 2015 Huawei Inc. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; + * version 2.1 of the License (not later!) + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this program; if not, see <http://www.gnu.org/licenses> + */ + +#include <stdlib.h> +#include <string.h> +#include <memory.h> +#include <unistd.h> +#include <asm/unistd.h> +#include <errno.h> +#include <linux/bpf.h> +#include "bpf.h" +#include "libbpf.h" +#include "libbpf_internal.h" + +/* + * When building perf, unistd.h is overridden. __NR_bpf is + * required to be defined explicitly. + */ +#ifndef __NR_bpf +# if defined(__i386__) +# define __NR_bpf 357 +# elif defined(__x86_64__) +# define __NR_bpf 321 +# elif defined(__aarch64__) +# define __NR_bpf 280 +# elif defined(__sparc__) +# define __NR_bpf 349 +# elif defined(__s390__) +# define __NR_bpf 351 +# elif defined(__arc__) +# define __NR_bpf 280 +# else +# error __NR_bpf not defined. libbpf does not support your arch. +# endif +#endif + +static inline __u64 ptr_to_u64(const void *ptr) +{ + return (__u64) (unsigned long) ptr; +} + +static inline int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr, + unsigned int size) +{ + return syscall(__NR_bpf, cmd, attr, size); +} + +static inline int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size) +{ + int fd; + + do { + fd = sys_bpf(BPF_PROG_LOAD, attr, size); + } while (fd < 0 && errno == EAGAIN); + + return fd; +} + +int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr) +{ + union bpf_attr attr; + + memset(&attr, '\0', sizeof(attr)); + + attr.map_type = create_attr->map_type; + attr.key_size = create_attr->key_size; + attr.value_size = create_attr->value_size; + attr.max_entries = create_attr->max_entries; + attr.map_flags = create_attr->map_flags; + if (create_attr->name) + memcpy(attr.map_name, create_attr->name, + min(strlen(create_attr->name), BPF_OBJ_NAME_LEN - 1)); + attr.numa_node = create_attr->numa_node; + attr.btf_fd = create_attr->btf_fd; + attr.btf_key_type_id = create_attr->btf_key_type_id; + attr.btf_value_type_id = create_attr->btf_value_type_id; + attr.map_ifindex = create_attr->map_ifindex; + if (attr.map_type == BPF_MAP_TYPE_STRUCT_OPS) + attr.btf_vmlinux_value_type_id = + create_attr->btf_vmlinux_value_type_id; + else + attr.inner_map_fd = create_attr->inner_map_fd; + + return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr)); +} + +int bpf_create_map_node(enum bpf_map_type map_type, const char *name, + int key_size, int value_size, int max_entries, + __u32 map_flags, int node) +{ + struct bpf_create_map_attr map_attr = {}; + + map_attr.name = name; + map_attr.map_type = map_type; + map_attr.map_flags = map_flags; + map_attr.key_size = key_size; + map_attr.value_size = value_size; + map_attr.max_entries = max_entries; + if (node >= 0) { + map_attr.numa_node = node; + map_attr.map_flags |= BPF_F_NUMA_NODE; + } + + return bpf_create_map_xattr(&map_attr); +} + +int bpf_create_map(enum bpf_map_type map_type, int key_size, + int value_size, int max_entries, __u32 map_flags) +{ + struct bpf_create_map_attr map_attr = {}; + + map_attr.map_type = map_type; + map_attr.map_flags = map_flags; + map_attr.key_size = key_size; + map_attr.value_size = value_size; + map_attr.max_entries = max_entries; + + return bpf_create_map_xattr(&map_attr); +} + +int bpf_create_map_name(enum bpf_map_type map_type, const char *name, + int key_size, int value_size, int max_entries, + __u32 map_flags) +{ + struct bpf_create_map_attr map_attr = {}; + + map_attr.name = name; + map_attr.map_type = map_type; + map_attr.map_flags = map_flags; + map_attr.key_size = key_size; + map_attr.value_size = value_size; + map_attr.max_entries = max_entries; + + return bpf_create_map_xattr(&map_attr); +} + +int bpf_create_map_in_map_node(enum bpf_map_type map_type, const char *name, + int key_size, int inner_map_fd, int max_entries, + __u32 map_flags, int node) +{ + union bpf_attr attr; + + memset(&attr, '\0', sizeof(attr)); + + attr.map_type = map_type; + attr.key_size = key_size; + attr.value_size = 4; + attr.inner_map_fd = inner_map_fd; + attr.max_entries = max_entries; + attr.map_flags = map_flags; + if (name) + memcpy(attr.map_name, name, + min(strlen(name), BPF_OBJ_NAME_LEN - 1)); + + if (node >= 0) { + attr.map_flags |= BPF_F_NUMA_NODE; + attr.numa_node = node; + } + + return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr)); +} + +int bpf_create_map_in_map(enum bpf_map_type map_type, const char *name, + int key_size, int inner_map_fd, int max_entries, + __u32 map_flags) +{ + return bpf_create_map_in_map_node(map_type, name, key_size, + inner_map_fd, max_entries, map_flags, + -1); +} + +static void * +alloc_zero_tailing_info(const void *orecord, __u32 cnt, + __u32 actual_rec_size, __u32 expected_rec_size) +{ + __u64 info_len = (__u64)actual_rec_size * cnt; + void *info, *nrecord; + int i; + + info = malloc(info_len); + if (!info) + return NULL; + + /* zero out bytes kernel does not understand */ + nrecord = info; + for (i = 0; i < cnt; i++) { + memcpy(nrecord, orecord, expected_rec_size); + memset(nrecord + expected_rec_size, 0, + actual_rec_size - expected_rec_size); + orecord += actual_rec_size; + nrecord += actual_rec_size; + } + + return info; +} + +int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr, + char *log_buf, size_t log_buf_sz) +{ + void *finfo = NULL, *linfo = NULL; + union bpf_attr attr; + __u32 log_level; + int fd; + + if (!load_attr || !log_buf != !log_buf_sz) + return -EINVAL; + + log_level = load_attr->log_level; + if (log_level > (4 | 2 | 1) || (log_level && !log_buf)) + return -EINVAL; + + memset(&attr, 0, sizeof(attr)); + attr.prog_type = load_attr->prog_type; + attr.expected_attach_type = load_attr->expected_attach_type; + if (attr.prog_type == BPF_PROG_TYPE_STRUCT_OPS || + attr.prog_type == BPF_PROG_TYPE_LSM) { + attr.attach_btf_id = load_attr->attach_btf_id; + } else if (attr.prog_type == BPF_PROG_TYPE_TRACING || + attr.prog_type == BPF_PROG_TYPE_EXT) { + attr.attach_btf_id = load_attr->attach_btf_id; + attr.attach_prog_fd = load_attr->attach_prog_fd; + } else { + attr.prog_ifindex = load_attr->prog_ifindex; + attr.kern_version = load_attr->kern_version; + } + attr.insn_cnt = (__u32)load_attr->insns_cnt; + attr.insns = ptr_to_u64(load_attr->insns); + attr.license = ptr_to_u64(load_attr->license); + + attr.log_level = log_level; + if (log_level) { + attr.log_buf = ptr_to_u64(log_buf); + attr.log_size = log_buf_sz; + } else { + attr.log_buf = ptr_to_u64(NULL); + attr.log_size = 0; + } + + attr.prog_btf_fd = load_attr->prog_btf_fd; + attr.func_info_rec_size = load_attr->func_info_rec_size; + attr.func_info_cnt = load_attr->func_info_cnt; + attr.func_info = ptr_to_u64(load_attr->func_info); + attr.line_info_rec_size = load_attr->line_info_rec_size; + attr.line_info_cnt = load_attr->line_info_cnt; + attr.line_info = ptr_to_u64(load_attr->line_info); + if (load_attr->name) + memcpy(attr.prog_name, load_attr->name, + min(strlen(load_attr->name), BPF_OBJ_NAME_LEN - 1)); + attr.prog_flags = load_attr->prog_flags; + + fd = sys_bpf_prog_load(&attr, sizeof(attr)); + if (fd >= 0) + return fd; + + /* After bpf_prog_load, the kernel may modify certain attributes + * to give user space a hint how to deal with loading failure. + * Check to see whether we can make some changes and load again. + */ + while (errno == E2BIG && (!finfo || !linfo)) { + if (!finfo && attr.func_info_cnt && + attr.func_info_rec_size < load_attr->func_info_rec_size) { + /* try with corrected func info records */ + finfo = alloc_zero_tailing_info(load_attr->func_info, + load_attr->func_info_cnt, + load_attr->func_info_rec_size, + attr.func_info_rec_size); + if (!finfo) + goto done; + + attr.func_info = ptr_to_u64(finfo); + attr.func_info_rec_size = load_attr->func_info_rec_size; + } else if (!linfo && attr.line_info_cnt && + attr.line_info_rec_size < + load_attr->line_info_rec_size) { + linfo = alloc_zero_tailing_info(load_attr->line_info, + load_attr->line_info_cnt, + load_attr->line_info_rec_size, + attr.line_info_rec_size); + if (!linfo) + goto done; + + attr.line_info = ptr_to_u64(linfo); + attr.line_info_rec_size = load_attr->line_info_rec_size; + } else { + break; + } + + fd = sys_bpf_prog_load(&attr, sizeof(attr)); + + if (fd >= 0) + goto done; + } + + if (log_level || !log_buf) + goto done; + + /* Try again with log */ + attr.log_buf = ptr_to_u64(log_buf); + attr.log_size = log_buf_sz; + attr.log_level = 1; + log_buf[0] = 0; + fd = sys_bpf_prog_load(&attr, sizeof(attr)); +done: + free(finfo); + free(linfo); + return fd; +} + +int bpf_load_program(enum bpf_prog_type type, const struct bpf_insn *insns, + size_t insns_cnt, const char *license, + __u32 kern_version, char *log_buf, + size_t log_buf_sz) +{ + struct bpf_load_program_attr load_attr; + + memset(&load_attr, 0, sizeof(struct bpf_load_program_attr)); + load_attr.prog_type = type; + load_attr.expected_attach_type = 0; + load_attr.name = NULL; + load_attr.insns = insns; + load_attr.insns_cnt = insns_cnt; + load_attr.license = license; + load_attr.kern_version = kern_version; + + return bpf_load_program_xattr(&load_attr, log_buf, log_buf_sz); +} + +int bpf_verify_program(enum bpf_prog_type type, const struct bpf_insn *insns, + size_t insns_cnt, __u32 prog_flags, const char *license, + __u32 kern_version, char *log_buf, size_t log_buf_sz, + int log_level) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.prog_type = type; + attr.insn_cnt = (__u32)insns_cnt; + attr.insns = ptr_to_u64(insns); + attr.license = ptr_to_u64(license); + attr.log_buf = ptr_to_u64(log_buf); + attr.log_size = log_buf_sz; + attr.log_level = log_level; + log_buf[0] = 0; + attr.kern_version = kern_version; + attr.prog_flags = prog_flags; + + return sys_bpf_prog_load(&attr, sizeof(attr)); +} + +int bpf_map_update_elem(int fd, const void *key, const void *value, + __u64 flags) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.map_fd = fd; + attr.key = ptr_to_u64(key); + attr.value = ptr_to_u64(value); + attr.flags = flags; + + return sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr)); +} + +int bpf_map_lookup_elem(int fd, const void *key, void *value) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.map_fd = fd; + attr.key = ptr_to_u64(key); + attr.value = ptr_to_u64(value); + + return sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr)); +} + +int bpf_map_lookup_elem_flags(int fd, const void *key, void *value, __u64 flags) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.map_fd = fd; + attr.key = ptr_to_u64(key); + attr.value = ptr_to_u64(value); + attr.flags = flags; + + return sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr)); +} + +int bpf_map_lookup_and_delete_elem(int fd, const void *key, void *value) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.map_fd = fd; + attr.key = ptr_to_u64(key); + attr.value = ptr_to_u64(value); + + return sys_bpf(BPF_MAP_LOOKUP_AND_DELETE_ELEM, &attr, sizeof(attr)); +} + +int bpf_map_delete_elem(int fd, const void *key) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.map_fd = fd; + attr.key = ptr_to_u64(key); + + return sys_bpf(BPF_MAP_DELETE_ELEM, &attr, sizeof(attr)); +} + +int bpf_map_get_next_key(int fd, const void *key, void *next_key) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.map_fd = fd; + attr.key = ptr_to_u64(key); + attr.next_key = ptr_to_u64(next_key); + + return sys_bpf(BPF_MAP_GET_NEXT_KEY, &attr, sizeof(attr)); +} + +int bpf_map_freeze(int fd) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.map_fd = fd; + + return sys_bpf(BPF_MAP_FREEZE, &attr, sizeof(attr)); +} + +static int bpf_map_batch_common(int cmd, int fd, void *in_batch, + void *out_batch, void *keys, void *values, + __u32 *count, + const struct bpf_map_batch_opts *opts) +{ + union bpf_attr attr; + int ret; + + if (!OPTS_VALID(opts, bpf_map_batch_opts)) + return -EINVAL; + + memset(&attr, 0, sizeof(attr)); + attr.batch.map_fd = fd; + attr.batch.in_batch = ptr_to_u64(in_batch); + attr.batch.out_batch = ptr_to_u64(out_batch); + attr.batch.keys = ptr_to_u64(keys); + attr.batch.values = ptr_to_u64(values); + attr.batch.count = *count; + attr.batch.elem_flags = OPTS_GET(opts, elem_flags, 0); + attr.batch.flags = OPTS_GET(opts, flags, 0); + + ret = sys_bpf(cmd, &attr, sizeof(attr)); + *count = attr.batch.count; + + return ret; +} + +int bpf_map_delete_batch(int fd, void *keys, __u32 *count, + const struct bpf_map_batch_opts *opts) +{ + return bpf_map_batch_common(BPF_MAP_DELETE_BATCH, fd, NULL, + NULL, keys, NULL, count, opts); +} + +int bpf_map_lookup_batch(int fd, void *in_batch, void *out_batch, void *keys, + void *values, __u32 *count, + const struct bpf_map_batch_opts *opts) +{ + return bpf_map_batch_common(BPF_MAP_LOOKUP_BATCH, fd, in_batch, + out_batch, keys, values, count, opts); +} + +int bpf_map_lookup_and_delete_batch(int fd, void *in_batch, void *out_batch, + void *keys, void *values, __u32 *count, + const struct bpf_map_batch_opts *opts) +{ + return bpf_map_batch_common(BPF_MAP_LOOKUP_AND_DELETE_BATCH, + fd, in_batch, out_batch, keys, values, + count, opts); +} + +int bpf_map_update_batch(int fd, void *keys, void *values, __u32 *count, + const struct bpf_map_batch_opts *opts) +{ + return bpf_map_batch_common(BPF_MAP_UPDATE_BATCH, fd, NULL, NULL, + keys, values, count, opts); +} + +int bpf_obj_pin(int fd, const char *pathname) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.pathname = ptr_to_u64((void *)pathname); + attr.bpf_fd = fd; + + return sys_bpf(BPF_OBJ_PIN, &attr, sizeof(attr)); +} + +int bpf_obj_get(const char *pathname) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.pathname = ptr_to_u64((void *)pathname); + + return sys_bpf(BPF_OBJ_GET, &attr, sizeof(attr)); +} + +int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type, + unsigned int flags) +{ + DECLARE_LIBBPF_OPTS(bpf_prog_attach_opts, opts, + .flags = flags, + ); + + return bpf_prog_attach_xattr(prog_fd, target_fd, type, &opts); +} + +int bpf_prog_attach_xattr(int prog_fd, int target_fd, + enum bpf_attach_type type, + const struct bpf_prog_attach_opts *opts) +{ + union bpf_attr attr; + + if (!OPTS_VALID(opts, bpf_prog_attach_opts)) + return -EINVAL; + + memset(&attr, 0, sizeof(attr)); + attr.target_fd = target_fd; + attr.attach_bpf_fd = prog_fd; + attr.attach_type = type; + attr.attach_flags = OPTS_GET(opts, flags, 0); + attr.replace_bpf_fd = OPTS_GET(opts, replace_prog_fd, 0); + + return sys_bpf(BPF_PROG_ATTACH, &attr, sizeof(attr)); +} + +int bpf_prog_detach(int target_fd, enum bpf_attach_type type) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.target_fd = target_fd; + attr.attach_type = type; + + return sys_bpf(BPF_PROG_DETACH, &attr, sizeof(attr)); +} + +int bpf_prog_detach2(int prog_fd, int target_fd, enum bpf_attach_type type) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.target_fd = target_fd; + attr.attach_bpf_fd = prog_fd; + attr.attach_type = type; + + return sys_bpf(BPF_PROG_DETACH, &attr, sizeof(attr)); +} + +int bpf_link_create(int prog_fd, int target_fd, + enum bpf_attach_type attach_type, + const struct bpf_link_create_opts *opts) +{ + __u32 target_btf_id, iter_info_len; + union bpf_attr attr; + + if (!OPTS_VALID(opts, bpf_link_create_opts)) + return -EINVAL; + + iter_info_len = OPTS_GET(opts, iter_info_len, 0); + target_btf_id = OPTS_GET(opts, target_btf_id, 0); + + if (iter_info_len && target_btf_id) + return -EINVAL; + + memset(&attr, 0, sizeof(attr)); + attr.link_create.prog_fd = prog_fd; + attr.link_create.target_fd = target_fd; + attr.link_create.attach_type = attach_type; + attr.link_create.flags = OPTS_GET(opts, flags, 0); + + if (iter_info_len) { + attr.link_create.iter_info = + ptr_to_u64(OPTS_GET(opts, iter_info, (void *)0)); + attr.link_create.iter_info_len = iter_info_len; + } else if (target_btf_id) { + attr.link_create.target_btf_id = target_btf_id; + } + + return sys_bpf(BPF_LINK_CREATE, &attr, sizeof(attr)); +} + +int bpf_link_detach(int link_fd) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.link_detach.link_fd = link_fd; + + return sys_bpf(BPF_LINK_DETACH, &attr, sizeof(attr)); +} + +int bpf_link_update(int link_fd, int new_prog_fd, + const struct bpf_link_update_opts *opts) +{ + union bpf_attr attr; + + if (!OPTS_VALID(opts, bpf_link_update_opts)) + return -EINVAL; + + memset(&attr, 0, sizeof(attr)); + attr.link_update.link_fd = link_fd; + attr.link_update.new_prog_fd = new_prog_fd; + attr.link_update.flags = OPTS_GET(opts, flags, 0); + attr.link_update.old_prog_fd = OPTS_GET(opts, old_prog_fd, 0); + + return sys_bpf(BPF_LINK_UPDATE, &attr, sizeof(attr)); +} + +int bpf_iter_create(int link_fd) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.iter_create.link_fd = link_fd; + + return sys_bpf(BPF_ITER_CREATE, &attr, sizeof(attr)); +} + +int bpf_prog_query(int target_fd, enum bpf_attach_type type, __u32 query_flags, + __u32 *attach_flags, __u32 *prog_ids, __u32 *prog_cnt) +{ + union bpf_attr attr; + int ret; + + memset(&attr, 0, sizeof(attr)); + attr.query.target_fd = target_fd; + attr.query.attach_type = type; + attr.query.query_flags = query_flags; + attr.query.prog_cnt = *prog_cnt; + attr.query.prog_ids = ptr_to_u64(prog_ids); + + ret = sys_bpf(BPF_PROG_QUERY, &attr, sizeof(attr)); + if (attach_flags) + *attach_flags = attr.query.attach_flags; + *prog_cnt = attr.query.prog_cnt; + return ret; +} + +int bpf_prog_test_run(int prog_fd, int repeat, void *data, __u32 size, + void *data_out, __u32 *size_out, __u32 *retval, + __u32 *duration) +{ + union bpf_attr attr; + int ret; + + memset(&attr, 0, sizeof(attr)); + attr.test.prog_fd = prog_fd; + attr.test.data_in = ptr_to_u64(data); + attr.test.data_out = ptr_to_u64(data_out); + attr.test.data_size_in = size; + attr.test.repeat = repeat; + + ret = sys_bpf(BPF_PROG_TEST_RUN, &attr, sizeof(attr)); + if (size_out) + *size_out = attr.test.data_size_out; + if (retval) + *retval = attr.test.retval; + if (duration) + *duration = attr.test.duration; + return ret; +} + +int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr) +{ + union bpf_attr attr; + int ret; + + if (!test_attr->data_out && test_attr->data_size_out > 0) + return -EINVAL; + + memset(&attr, 0, sizeof(attr)); + attr.test.prog_fd = test_attr->prog_fd; + attr.test.data_in = ptr_to_u64(test_attr->data_in); + attr.test.data_out = ptr_to_u64(test_attr->data_out); + attr.test.data_size_in = test_attr->data_size_in; + attr.test.data_size_out = test_attr->data_size_out; + attr.test.ctx_in = ptr_to_u64(test_attr->ctx_in); + attr.test.ctx_out = ptr_to_u64(test_attr->ctx_out); + attr.test.ctx_size_in = test_attr->ctx_size_in; + attr.test.ctx_size_out = test_attr->ctx_size_out; + attr.test.repeat = test_attr->repeat; + + ret = sys_bpf(BPF_PROG_TEST_RUN, &attr, sizeof(attr)); + test_attr->data_size_out = attr.test.data_size_out; + test_attr->ctx_size_out = attr.test.ctx_size_out; + test_attr->retval = attr.test.retval; + test_attr->duration = attr.test.duration; + return ret; +} + +int bpf_prog_test_run_opts(int prog_fd, struct bpf_test_run_opts *opts) +{ + union bpf_attr attr; + int ret; + + if (!OPTS_VALID(opts, bpf_test_run_opts)) + return -EINVAL; + + memset(&attr, 0, sizeof(attr)); + attr.test.prog_fd = prog_fd; + attr.test.cpu = OPTS_GET(opts, cpu, 0); + attr.test.flags = OPTS_GET(opts, flags, 0); + attr.test.repeat = OPTS_GET(opts, repeat, 0); + attr.test.duration = OPTS_GET(opts, duration, 0); + attr.test.ctx_size_in = OPTS_GET(opts, ctx_size_in, 0); + attr.test.ctx_size_out = OPTS_GET(opts, ctx_size_out, 0); + attr.test.data_size_in = OPTS_GET(opts, data_size_in, 0); + attr.test.data_size_out = OPTS_GET(opts, data_size_out, 0); + attr.test.ctx_in = ptr_to_u64(OPTS_GET(opts, ctx_in, NULL)); + attr.test.ctx_out = ptr_to_u64(OPTS_GET(opts, ctx_out, NULL)); + attr.test.data_in = ptr_to_u64(OPTS_GET(opts, data_in, NULL)); + attr.test.data_out = ptr_to_u64(OPTS_GET(opts, data_out, NULL)); + + ret = sys_bpf(BPF_PROG_TEST_RUN, &attr, sizeof(attr)); + OPTS_SET(opts, data_size_out, attr.test.data_size_out); + OPTS_SET(opts, ctx_size_out, attr.test.ctx_size_out); + OPTS_SET(opts, duration, attr.test.duration); + OPTS_SET(opts, retval, attr.test.retval); + return ret; +} + +static int bpf_obj_get_next_id(__u32 start_id, __u32 *next_id, int cmd) +{ + union bpf_attr attr; + int err; + + memset(&attr, 0, sizeof(attr)); + attr.start_id = start_id; + + err = sys_bpf(cmd, &attr, sizeof(attr)); + if (!err) + *next_id = attr.next_id; + + return err; +} + +int bpf_prog_get_next_id(__u32 start_id, __u32 *next_id) +{ + return bpf_obj_get_next_id(start_id, next_id, BPF_PROG_GET_NEXT_ID); +} + +int bpf_map_get_next_id(__u32 start_id, __u32 *next_id) +{ + return bpf_obj_get_next_id(start_id, next_id, BPF_MAP_GET_NEXT_ID); +} + +int bpf_btf_get_next_id(__u32 start_id, __u32 *next_id) +{ + return bpf_obj_get_next_id(start_id, next_id, BPF_BTF_GET_NEXT_ID); +} + +int bpf_link_get_next_id(__u32 start_id, __u32 *next_id) +{ + return bpf_obj_get_next_id(start_id, next_id, BPF_LINK_GET_NEXT_ID); +} + +int bpf_prog_get_fd_by_id(__u32 id) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.prog_id = id; + + return sys_bpf(BPF_PROG_GET_FD_BY_ID, &attr, sizeof(attr)); +} + +int bpf_map_get_fd_by_id(__u32 id) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.map_id = id; + + return sys_bpf(BPF_MAP_GET_FD_BY_ID, &attr, sizeof(attr)); +} + +int bpf_btf_get_fd_by_id(__u32 id) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.btf_id = id; + + return sys_bpf(BPF_BTF_GET_FD_BY_ID, &attr, sizeof(attr)); +} + +int bpf_link_get_fd_by_id(__u32 id) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.link_id = id; + + return sys_bpf(BPF_LINK_GET_FD_BY_ID, &attr, sizeof(attr)); +} + +int bpf_obj_get_info_by_fd(int bpf_fd, void *info, __u32 *info_len) +{ + union bpf_attr attr; + int err; + + memset(&attr, 0, sizeof(attr)); + attr.info.bpf_fd = bpf_fd; + attr.info.info_len = *info_len; + attr.info.info = ptr_to_u64(info); + + err = sys_bpf(BPF_OBJ_GET_INFO_BY_FD, &attr, sizeof(attr)); + if (!err) + *info_len = attr.info.info_len; + + return err; +} + +int bpf_raw_tracepoint_open(const char *name, int prog_fd) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.raw_tracepoint.name = ptr_to_u64(name); + attr.raw_tracepoint.prog_fd = prog_fd; + + return sys_bpf(BPF_RAW_TRACEPOINT_OPEN, &attr, sizeof(attr)); +} + +int bpf_load_btf(const void *btf, __u32 btf_size, char *log_buf, __u32 log_buf_size, + bool do_log) +{ + union bpf_attr attr = {}; + int fd; + + attr.btf = ptr_to_u64(btf); + attr.btf_size = btf_size; + +retry: + if (do_log && log_buf && log_buf_size) { + attr.btf_log_level = 1; + attr.btf_log_size = log_buf_size; + attr.btf_log_buf = ptr_to_u64(log_buf); + } + + fd = sys_bpf(BPF_BTF_LOAD, &attr, sizeof(attr)); + if (fd == -1 && !do_log && log_buf && log_buf_size) { + do_log = true; + goto retry; + } + + return fd; +} + +int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf, __u32 *buf_len, + __u32 *prog_id, __u32 *fd_type, __u64 *probe_offset, + __u64 *probe_addr) +{ + union bpf_attr attr = {}; + int err; + + attr.task_fd_query.pid = pid; + attr.task_fd_query.fd = fd; + attr.task_fd_query.flags = flags; + attr.task_fd_query.buf = ptr_to_u64(buf); + attr.task_fd_query.buf_len = *buf_len; + + err = sys_bpf(BPF_TASK_FD_QUERY, &attr, sizeof(attr)); + *buf_len = attr.task_fd_query.buf_len; + *prog_id = attr.task_fd_query.prog_id; + *fd_type = attr.task_fd_query.fd_type; + *probe_offset = attr.task_fd_query.probe_offset; + *probe_addr = attr.task_fd_query.probe_addr; + + return err; +} + +int bpf_enable_stats(enum bpf_stats_type type) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.enable_stats.type = type; + + return sys_bpf(BPF_ENABLE_STATS, &attr, sizeof(attr)); +} + +int bpf_prog_bind_map(int prog_fd, int map_fd, + const struct bpf_prog_bind_opts *opts) +{ + union bpf_attr attr; + + if (!OPTS_VALID(opts, bpf_prog_bind_opts)) + return -EINVAL; + + memset(&attr, 0, sizeof(attr)); + attr.prog_bind_map.prog_fd = prog_fd; + attr.prog_bind_map.map_fd = map_fd; + attr.prog_bind_map.flags = OPTS_GET(opts, flags, 0); + + return sys_bpf(BPF_PROG_BIND_MAP, &attr, sizeof(attr)); +} diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h new file mode 100644 index 000000000..92a3eaa15 --- /dev/null +++ b/tools/lib/bpf/bpf.h @@ -0,0 +1,292 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ + +/* + * common eBPF ELF operations. + * + * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org> + * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com> + * Copyright (C) 2015 Huawei Inc. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; + * version 2.1 of the License (not later!) + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this program; if not, see <http://www.gnu.org/licenses> + */ +#ifndef __LIBBPF_BPF_H +#define __LIBBPF_BPF_H + +#include <linux/bpf.h> +#include <stdbool.h> +#include <stddef.h> +#include <stdint.h> + +#include "libbpf_common.h" + +#ifdef __cplusplus +extern "C" { +#endif + +struct bpf_create_map_attr { + const char *name; + enum bpf_map_type map_type; + __u32 map_flags; + __u32 key_size; + __u32 value_size; + __u32 max_entries; + __u32 numa_node; + __u32 btf_fd; + __u32 btf_key_type_id; + __u32 btf_value_type_id; + __u32 map_ifindex; + union { + __u32 inner_map_fd; + __u32 btf_vmlinux_value_type_id; + }; +}; + +LIBBPF_API int +bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr); +LIBBPF_API int bpf_create_map_node(enum bpf_map_type map_type, const char *name, + int key_size, int value_size, + int max_entries, __u32 map_flags, int node); +LIBBPF_API int bpf_create_map_name(enum bpf_map_type map_type, const char *name, + int key_size, int value_size, + int max_entries, __u32 map_flags); +LIBBPF_API int bpf_create_map(enum bpf_map_type map_type, int key_size, + int value_size, int max_entries, __u32 map_flags); +LIBBPF_API int bpf_create_map_in_map_node(enum bpf_map_type map_type, + const char *name, int key_size, + int inner_map_fd, int max_entries, + __u32 map_flags, int node); +LIBBPF_API int bpf_create_map_in_map(enum bpf_map_type map_type, + const char *name, int key_size, + int inner_map_fd, int max_entries, + __u32 map_flags); + +struct bpf_load_program_attr { + enum bpf_prog_type prog_type; + enum bpf_attach_type expected_attach_type; + const char *name; + const struct bpf_insn *insns; + size_t insns_cnt; + const char *license; + union { + __u32 kern_version; + __u32 attach_prog_fd; + }; + union { + __u32 prog_ifindex; + __u32 attach_btf_id; + }; + __u32 prog_btf_fd; + __u32 func_info_rec_size; + const void *func_info; + __u32 func_info_cnt; + __u32 line_info_rec_size; + const void *line_info; + __u32 line_info_cnt; + __u32 log_level; + __u32 prog_flags; +}; + +/* Flags to direct loading requirements */ +#define MAPS_RELAX_COMPAT 0x01 + +/* Recommend log buffer size */ +#define BPF_LOG_BUF_SIZE (UINT32_MAX >> 8) /* verifier maximum in kernels <= 5.1 */ +LIBBPF_API int +bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr, + char *log_buf, size_t log_buf_sz); +LIBBPF_API int bpf_load_program(enum bpf_prog_type type, + const struct bpf_insn *insns, size_t insns_cnt, + const char *license, __u32 kern_version, + char *log_buf, size_t log_buf_sz); +LIBBPF_API int bpf_verify_program(enum bpf_prog_type type, + const struct bpf_insn *insns, + size_t insns_cnt, __u32 prog_flags, + const char *license, __u32 kern_version, + char *log_buf, size_t log_buf_sz, + int log_level); + +LIBBPF_API int bpf_map_update_elem(int fd, const void *key, const void *value, + __u64 flags); + +LIBBPF_API int bpf_map_lookup_elem(int fd, const void *key, void *value); +LIBBPF_API int bpf_map_lookup_elem_flags(int fd, const void *key, void *value, + __u64 flags); +LIBBPF_API int bpf_map_lookup_and_delete_elem(int fd, const void *key, + void *value); +LIBBPF_API int bpf_map_delete_elem(int fd, const void *key); +LIBBPF_API int bpf_map_get_next_key(int fd, const void *key, void *next_key); +LIBBPF_API int bpf_map_freeze(int fd); + +struct bpf_map_batch_opts { + size_t sz; /* size of this struct for forward/backward compatibility */ + __u64 elem_flags; + __u64 flags; +}; +#define bpf_map_batch_opts__last_field flags + +LIBBPF_API int bpf_map_delete_batch(int fd, void *keys, + __u32 *count, + const struct bpf_map_batch_opts *opts); +LIBBPF_API int bpf_map_lookup_batch(int fd, void *in_batch, void *out_batch, + void *keys, void *values, __u32 *count, + const struct bpf_map_batch_opts *opts); +LIBBPF_API int bpf_map_lookup_and_delete_batch(int fd, void *in_batch, + void *out_batch, void *keys, + void *values, __u32 *count, + const struct bpf_map_batch_opts *opts); +LIBBPF_API int bpf_map_update_batch(int fd, void *keys, void *values, + __u32 *count, + const struct bpf_map_batch_opts *opts); + +LIBBPF_API int bpf_obj_pin(int fd, const char *pathname); +LIBBPF_API int bpf_obj_get(const char *pathname); + +struct bpf_prog_attach_opts { + size_t sz; /* size of this struct for forward/backward compatibility */ + unsigned int flags; + int replace_prog_fd; +}; +#define bpf_prog_attach_opts__last_field replace_prog_fd + +LIBBPF_API int bpf_prog_attach(int prog_fd, int attachable_fd, + enum bpf_attach_type type, unsigned int flags); +LIBBPF_API int bpf_prog_attach_xattr(int prog_fd, int attachable_fd, + enum bpf_attach_type type, + const struct bpf_prog_attach_opts *opts); +LIBBPF_API int bpf_prog_detach(int attachable_fd, enum bpf_attach_type type); +LIBBPF_API int bpf_prog_detach2(int prog_fd, int attachable_fd, + enum bpf_attach_type type); + +union bpf_iter_link_info; /* defined in up-to-date linux/bpf.h */ +struct bpf_link_create_opts { + size_t sz; /* size of this struct for forward/backward compatibility */ + __u32 flags; + union bpf_iter_link_info *iter_info; + __u32 iter_info_len; + __u32 target_btf_id; +}; +#define bpf_link_create_opts__last_field target_btf_id + +LIBBPF_API int bpf_link_create(int prog_fd, int target_fd, + enum bpf_attach_type attach_type, + const struct bpf_link_create_opts *opts); + +LIBBPF_API int bpf_link_detach(int link_fd); + +struct bpf_link_update_opts { + size_t sz; /* size of this struct for forward/backward compatibility */ + __u32 flags; /* extra flags */ + __u32 old_prog_fd; /* expected old program FD */ +}; +#define bpf_link_update_opts__last_field old_prog_fd + +LIBBPF_API int bpf_link_update(int link_fd, int new_prog_fd, + const struct bpf_link_update_opts *opts); + +LIBBPF_API int bpf_iter_create(int link_fd); + +struct bpf_prog_test_run_attr { + int prog_fd; + int repeat; + const void *data_in; + __u32 data_size_in; + void *data_out; /* optional */ + __u32 data_size_out; /* in: max length of data_out + * out: length of data_out */ + __u32 retval; /* out: return code of the BPF program */ + __u32 duration; /* out: average per repetition in ns */ + const void *ctx_in; /* optional */ + __u32 ctx_size_in; + void *ctx_out; /* optional */ + __u32 ctx_size_out; /* in: max length of ctx_out + * out: length of cxt_out */ +}; + +LIBBPF_API int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr); + +/* + * bpf_prog_test_run does not check that data_out is large enough. Consider + * using bpf_prog_test_run_xattr instead. + */ +LIBBPF_API int bpf_prog_test_run(int prog_fd, int repeat, void *data, + __u32 size, void *data_out, __u32 *size_out, + __u32 *retval, __u32 *duration); +LIBBPF_API int bpf_prog_get_next_id(__u32 start_id, __u32 *next_id); +LIBBPF_API int bpf_map_get_next_id(__u32 start_id, __u32 *next_id); +LIBBPF_API int bpf_btf_get_next_id(__u32 start_id, __u32 *next_id); +LIBBPF_API int bpf_link_get_next_id(__u32 start_id, __u32 *next_id); +LIBBPF_API int bpf_prog_get_fd_by_id(__u32 id); +LIBBPF_API int bpf_map_get_fd_by_id(__u32 id); +LIBBPF_API int bpf_btf_get_fd_by_id(__u32 id); +LIBBPF_API int bpf_link_get_fd_by_id(__u32 id); +LIBBPF_API int bpf_obj_get_info_by_fd(int bpf_fd, void *info, __u32 *info_len); +LIBBPF_API int bpf_prog_query(int target_fd, enum bpf_attach_type type, + __u32 query_flags, __u32 *attach_flags, + __u32 *prog_ids, __u32 *prog_cnt); +LIBBPF_API int bpf_raw_tracepoint_open(const char *name, int prog_fd); +LIBBPF_API int bpf_load_btf(const void *btf, __u32 btf_size, char *log_buf, + __u32 log_buf_size, bool do_log); +LIBBPF_API int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf, + __u32 *buf_len, __u32 *prog_id, __u32 *fd_type, + __u64 *probe_offset, __u64 *probe_addr); + +#ifdef __cplusplus +/* forward-declaring enums in C++ isn't compatible with pure C enums, so + * instead define bpf_enable_stats() as accepting int as an input + */ +LIBBPF_API int bpf_enable_stats(int type); +#else +enum bpf_stats_type; /* defined in up-to-date linux/bpf.h */ +LIBBPF_API int bpf_enable_stats(enum bpf_stats_type type); +#endif + +struct bpf_prog_bind_opts { + size_t sz; /* size of this struct for forward/backward compatibility */ + __u32 flags; +}; +#define bpf_prog_bind_opts__last_field flags + +LIBBPF_API int bpf_prog_bind_map(int prog_fd, int map_fd, + const struct bpf_prog_bind_opts *opts); + +struct bpf_test_run_opts { + size_t sz; /* size of this struct for forward/backward compatibility */ + const void *data_in; /* optional */ + void *data_out; /* optional */ + __u32 data_size_in; + __u32 data_size_out; /* in: max length of data_out + * out: length of data_out + */ + const void *ctx_in; /* optional */ + void *ctx_out; /* optional */ + __u32 ctx_size_in; + __u32 ctx_size_out; /* in: max length of ctx_out + * out: length of cxt_out + */ + __u32 retval; /* out: return code of the BPF program */ + int repeat; + __u32 duration; /* out: average per repetition in ns */ + __u32 flags; + __u32 cpu; +}; +#define bpf_test_run_opts__last_field cpu + +LIBBPF_API int bpf_prog_test_run_opts(int prog_fd, + struct bpf_test_run_opts *opts); + +#ifdef __cplusplus +} /* extern "C" */ +#endif + +#endif /* __LIBBPF_BPF_H */ diff --git a/tools/lib/bpf/bpf_core_read.h b/tools/lib/bpf/bpf_core_read.h new file mode 100644 index 000000000..f05cfc082 --- /dev/null +++ b/tools/lib/bpf/bpf_core_read.h @@ -0,0 +1,353 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ +#ifndef __BPF_CORE_READ_H__ +#define __BPF_CORE_READ_H__ + +/* + * enum bpf_field_info_kind is passed as a second argument into + * __builtin_preserve_field_info() built-in to get a specific aspect of + * a field, captured as a first argument. __builtin_preserve_field_info(field, + * info_kind) returns __u32 integer and produces BTF field relocation, which + * is understood and processed by libbpf during BPF object loading. See + * selftests/bpf for examples. + */ +enum bpf_field_info_kind { + BPF_FIELD_BYTE_OFFSET = 0, /* field byte offset */ + BPF_FIELD_BYTE_SIZE = 1, + BPF_FIELD_EXISTS = 2, /* field existence in target kernel */ + BPF_FIELD_SIGNED = 3, + BPF_FIELD_LSHIFT_U64 = 4, + BPF_FIELD_RSHIFT_U64 = 5, +}; + +/* second argument to __builtin_btf_type_id() built-in */ +enum bpf_type_id_kind { + BPF_TYPE_ID_LOCAL = 0, /* BTF type ID in local program */ + BPF_TYPE_ID_TARGET = 1, /* BTF type ID in target kernel */ +}; + +/* second argument to __builtin_preserve_type_info() built-in */ +enum bpf_type_info_kind { + BPF_TYPE_EXISTS = 0, /* type existence in target kernel */ + BPF_TYPE_SIZE = 1, /* type size in target kernel */ +}; + +/* second argument to __builtin_preserve_enum_value() built-in */ +enum bpf_enum_value_kind { + BPF_ENUMVAL_EXISTS = 0, /* enum value existence in kernel */ + BPF_ENUMVAL_VALUE = 1, /* enum value value relocation */ +}; + +#define __CORE_RELO(src, field, info) \ + __builtin_preserve_field_info((src)->field, BPF_FIELD_##info) + +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ +#define __CORE_BITFIELD_PROBE_READ(dst, src, fld) \ + bpf_probe_read_kernel( \ + (void *)dst, \ + __CORE_RELO(src, fld, BYTE_SIZE), \ + (const void *)src + __CORE_RELO(src, fld, BYTE_OFFSET)) +#else +/* semantics of LSHIFT_64 assumes loading values into low-ordered bytes, so + * for big-endian we need to adjust destination pointer accordingly, based on + * field byte size + */ +#define __CORE_BITFIELD_PROBE_READ(dst, src, fld) \ + bpf_probe_read_kernel( \ + (void *)dst + (8 - __CORE_RELO(src, fld, BYTE_SIZE)), \ + __CORE_RELO(src, fld, BYTE_SIZE), \ + (const void *)src + __CORE_RELO(src, fld, BYTE_OFFSET)) +#endif + +/* + * Extract bitfield, identified by s->field, and return its value as u64. + * All this is done in relocatable manner, so bitfield changes such as + * signedness, bit size, offset changes, this will be handled automatically. + * This version of macro is using bpf_probe_read_kernel() to read underlying + * integer storage. Macro functions as an expression and its return type is + * bpf_probe_read_kernel()'s return value: 0, on success, <0 on error. + */ +#define BPF_CORE_READ_BITFIELD_PROBED(s, field) ({ \ + unsigned long long val = 0; \ + \ + __CORE_BITFIELD_PROBE_READ(&val, s, field); \ + val <<= __CORE_RELO(s, field, LSHIFT_U64); \ + if (__CORE_RELO(s, field, SIGNED)) \ + val = ((long long)val) >> __CORE_RELO(s, field, RSHIFT_U64); \ + else \ + val = val >> __CORE_RELO(s, field, RSHIFT_U64); \ + val; \ +}) + +/* + * Extract bitfield, identified by s->field, and return its value as u64. + * This version of macro is using direct memory reads and should be used from + * BPF program types that support such functionality (e.g., typed raw + * tracepoints). + */ +#define BPF_CORE_READ_BITFIELD(s, field) ({ \ + const void *p = (const void *)s + __CORE_RELO(s, field, BYTE_OFFSET); \ + unsigned long long val; \ + \ + /* This is a so-called barrier_var() operation that makes specified \ + * variable "a black box" for optimizing compiler. \ + * It forces compiler to perform BYTE_OFFSET relocation on p and use \ + * its calculated value in the switch below, instead of applying \ + * the same relocation 4 times for each individual memory load. \ + */ \ + asm volatile("" : "=r"(p) : "0"(p)); \ + \ + switch (__CORE_RELO(s, field, BYTE_SIZE)) { \ + case 1: val = *(const unsigned char *)p; break; \ + case 2: val = *(const unsigned short *)p; break; \ + case 4: val = *(const unsigned int *)p; break; \ + case 8: val = *(const unsigned long long *)p; break; \ + } \ + val <<= __CORE_RELO(s, field, LSHIFT_U64); \ + if (__CORE_RELO(s, field, SIGNED)) \ + val = ((long long)val) >> __CORE_RELO(s, field, RSHIFT_U64); \ + else \ + val = val >> __CORE_RELO(s, field, RSHIFT_U64); \ + val; \ +}) + +/* + * Convenience macro to check that field actually exists in target kernel's. + * Returns: + * 1, if matching field is present in target kernel; + * 0, if no matching field found. + */ +#define bpf_core_field_exists(field) \ + __builtin_preserve_field_info(field, BPF_FIELD_EXISTS) + +/* + * Convenience macro to get the byte size of a field. Works for integers, + * struct/unions, pointers, arrays, and enums. + */ +#define bpf_core_field_size(field) \ + __builtin_preserve_field_info(field, BPF_FIELD_BYTE_SIZE) + +/* + * Convenience macro to get BTF type ID of a specified type, using a local BTF + * information. Return 32-bit unsigned integer with type ID from program's own + * BTF. Always succeeds. + */ +#define bpf_core_type_id_local(type) \ + __builtin_btf_type_id(*(typeof(type) *)0, BPF_TYPE_ID_LOCAL) + +/* + * Convenience macro to get BTF type ID of a target kernel's type that matches + * specified local type. + * Returns: + * - valid 32-bit unsigned type ID in kernel BTF; + * - 0, if no matching type was found in a target kernel BTF. + */ +#define bpf_core_type_id_kernel(type) \ + __builtin_btf_type_id(*(typeof(type) *)0, BPF_TYPE_ID_TARGET) + +/* + * Convenience macro to check that provided named type + * (struct/union/enum/typedef) exists in a target kernel. + * Returns: + * 1, if such type is present in target kernel's BTF; + * 0, if no matching type is found. + */ +#define bpf_core_type_exists(type) \ + __builtin_preserve_type_info(*(typeof(type) *)0, BPF_TYPE_EXISTS) + +/* + * Convenience macro to get the byte size of a provided named type + * (struct/union/enum/typedef) in a target kernel. + * Returns: + * >= 0 size (in bytes), if type is present in target kernel's BTF; + * 0, if no matching type is found. + */ +#define bpf_core_type_size(type) \ + __builtin_preserve_type_info(*(typeof(type) *)0, BPF_TYPE_SIZE) + +/* + * Convenience macro to check that provided enumerator value is defined in + * a target kernel. + * Returns: + * 1, if specified enum type and its enumerator value are present in target + * kernel's BTF; + * 0, if no matching enum and/or enum value within that enum is found. + */ +#define bpf_core_enum_value_exists(enum_type, enum_value) \ + __builtin_preserve_enum_value(*(typeof(enum_type) *)enum_value, BPF_ENUMVAL_EXISTS) + +/* + * Convenience macro to get the integer value of an enumerator value in + * a target kernel. + * Returns: + * 64-bit value, if specified enum type and its enumerator value are + * present in target kernel's BTF; + * 0, if no matching enum and/or enum value within that enum is found. + */ +#define bpf_core_enum_value(enum_type, enum_value) \ + __builtin_preserve_enum_value(*(typeof(enum_type) *)enum_value, BPF_ENUMVAL_VALUE) + +/* + * bpf_core_read() abstracts away bpf_probe_read_kernel() call and captures + * offset relocation for source address using __builtin_preserve_access_index() + * built-in, provided by Clang. + * + * __builtin_preserve_access_index() takes as an argument an expression of + * taking an address of a field within struct/union. It makes compiler emit + * a relocation, which records BTF type ID describing root struct/union and an + * accessor string which describes exact embedded field that was used to take + * an address. See detailed description of this relocation format and + * semantics in comments to struct bpf_field_reloc in libbpf_internal.h. + * + * This relocation allows libbpf to adjust BPF instruction to use correct + * actual field offset, based on target kernel BTF type that matches original + * (local) BTF, used to record relocation. + */ +#define bpf_core_read(dst, sz, src) \ + bpf_probe_read_kernel(dst, sz, \ + (const void *)__builtin_preserve_access_index(src)) + +/* + * bpf_core_read_str() is a thin wrapper around bpf_probe_read_str() + * additionally emitting BPF CO-RE field relocation for specified source + * argument. + */ +#define bpf_core_read_str(dst, sz, src) \ + bpf_probe_read_kernel_str(dst, sz, \ + (const void *)__builtin_preserve_access_index(src)) + +#define ___concat(a, b) a ## b +#define ___apply(fn, n) ___concat(fn, n) +#define ___nth(_1, _2, _3, _4, _5, _6, _7, _8, _9, _10, __11, N, ...) N + +/* + * return number of provided arguments; used for switch-based variadic macro + * definitions (see ___last, ___arrow, etc below) + */ +#define ___narg(...) ___nth(_, ##__VA_ARGS__, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) +/* + * return 0 if no arguments are passed, N - otherwise; used for + * recursively-defined macros to specify termination (0) case, and generic + * (N) case (e.g., ___read_ptrs, ___core_read) + */ +#define ___empty(...) ___nth(_, ##__VA_ARGS__, N, N, N, N, N, N, N, N, N, N, 0) + +#define ___last1(x) x +#define ___last2(a, x) x +#define ___last3(a, b, x) x +#define ___last4(a, b, c, x) x +#define ___last5(a, b, c, d, x) x +#define ___last6(a, b, c, d, e, x) x +#define ___last7(a, b, c, d, e, f, x) x +#define ___last8(a, b, c, d, e, f, g, x) x +#define ___last9(a, b, c, d, e, f, g, h, x) x +#define ___last10(a, b, c, d, e, f, g, h, i, x) x +#define ___last(...) ___apply(___last, ___narg(__VA_ARGS__))(__VA_ARGS__) + +#define ___nolast2(a, _) a +#define ___nolast3(a, b, _) a, b +#define ___nolast4(a, b, c, _) a, b, c +#define ___nolast5(a, b, c, d, _) a, b, c, d +#define ___nolast6(a, b, c, d, e, _) a, b, c, d, e +#define ___nolast7(a, b, c, d, e, f, _) a, b, c, d, e, f +#define ___nolast8(a, b, c, d, e, f, g, _) a, b, c, d, e, f, g +#define ___nolast9(a, b, c, d, e, f, g, h, _) a, b, c, d, e, f, g, h +#define ___nolast10(a, b, c, d, e, f, g, h, i, _) a, b, c, d, e, f, g, h, i +#define ___nolast(...) ___apply(___nolast, ___narg(__VA_ARGS__))(__VA_ARGS__) + +#define ___arrow1(a) a +#define ___arrow2(a, b) a->b +#define ___arrow3(a, b, c) a->b->c +#define ___arrow4(a, b, c, d) a->b->c->d +#define ___arrow5(a, b, c, d, e) a->b->c->d->e +#define ___arrow6(a, b, c, d, e, f) a->b->c->d->e->f +#define ___arrow7(a, b, c, d, e, f, g) a->b->c->d->e->f->g +#define ___arrow8(a, b, c, d, e, f, g, h) a->b->c->d->e->f->g->h +#define ___arrow9(a, b, c, d, e, f, g, h, i) a->b->c->d->e->f->g->h->i +#define ___arrow10(a, b, c, d, e, f, g, h, i, j) a->b->c->d->e->f->g->h->i->j +#define ___arrow(...) ___apply(___arrow, ___narg(__VA_ARGS__))(__VA_ARGS__) + +#define ___type(...) typeof(___arrow(__VA_ARGS__)) + +#define ___read(read_fn, dst, src_type, src, accessor) \ + read_fn((void *)(dst), sizeof(*(dst)), &((src_type)(src))->accessor) + +/* "recursively" read a sequence of inner pointers using local __t var */ +#define ___rd_first(src, a) ___read(bpf_core_read, &__t, ___type(src), src, a); +#define ___rd_last(...) \ + ___read(bpf_core_read, &__t, \ + ___type(___nolast(__VA_ARGS__)), __t, ___last(__VA_ARGS__)); +#define ___rd_p1(...) const void *__t; ___rd_first(__VA_ARGS__) +#define ___rd_p2(...) ___rd_p1(___nolast(__VA_ARGS__)) ___rd_last(__VA_ARGS__) +#define ___rd_p3(...) ___rd_p2(___nolast(__VA_ARGS__)) ___rd_last(__VA_ARGS__) +#define ___rd_p4(...) ___rd_p3(___nolast(__VA_ARGS__)) ___rd_last(__VA_ARGS__) +#define ___rd_p5(...) ___rd_p4(___nolast(__VA_ARGS__)) ___rd_last(__VA_ARGS__) +#define ___rd_p6(...) ___rd_p5(___nolast(__VA_ARGS__)) ___rd_last(__VA_ARGS__) +#define ___rd_p7(...) ___rd_p6(___nolast(__VA_ARGS__)) ___rd_last(__VA_ARGS__) +#define ___rd_p8(...) ___rd_p7(___nolast(__VA_ARGS__)) ___rd_last(__VA_ARGS__) +#define ___rd_p9(...) ___rd_p8(___nolast(__VA_ARGS__)) ___rd_last(__VA_ARGS__) +#define ___read_ptrs(src, ...) \ + ___apply(___rd_p, ___narg(__VA_ARGS__))(src, __VA_ARGS__) + +#define ___core_read0(fn, dst, src, a) \ + ___read(fn, dst, ___type(src), src, a); +#define ___core_readN(fn, dst, src, ...) \ + ___read_ptrs(src, ___nolast(__VA_ARGS__)) \ + ___read(fn, dst, ___type(src, ___nolast(__VA_ARGS__)), __t, \ + ___last(__VA_ARGS__)); +#define ___core_read(fn, dst, src, a, ...) \ + ___apply(___core_read, ___empty(__VA_ARGS__))(fn, dst, \ + src, a, ##__VA_ARGS__) + +/* + * BPF_CORE_READ_INTO() is a more performance-conscious variant of + * BPF_CORE_READ(), in which final field is read into user-provided storage. + * See BPF_CORE_READ() below for more details on general usage. + */ +#define BPF_CORE_READ_INTO(dst, src, a, ...) \ + ({ \ + ___core_read(bpf_core_read, dst, (src), a, ##__VA_ARGS__) \ + }) + +/* + * BPF_CORE_READ_STR_INTO() does same "pointer chasing" as + * BPF_CORE_READ() for intermediate pointers, but then executes (and returns + * corresponding error code) bpf_core_read_str() for final string read. + */ +#define BPF_CORE_READ_STR_INTO(dst, src, a, ...) \ + ({ \ + ___core_read(bpf_core_read_str, dst, (src), a, ##__VA_ARGS__)\ + }) + +/* + * BPF_CORE_READ() is used to simplify BPF CO-RE relocatable read, especially + * when there are few pointer chasing steps. + * E.g., what in non-BPF world (or in BPF w/ BCC) would be something like: + * int x = s->a.b.c->d.e->f->g; + * can be succinctly achieved using BPF_CORE_READ as: + * int x = BPF_CORE_READ(s, a.b.c, d.e, f, g); + * + * BPF_CORE_READ will decompose above statement into 4 bpf_core_read (BPF + * CO-RE relocatable bpf_probe_read_kernel() wrapper) calls, logically + * equivalent to: + * 1. const void *__t = s->a.b.c; + * 2. __t = __t->d.e; + * 3. __t = __t->f; + * 4. return __t->g; + * + * Equivalence is logical, because there is a heavy type casting/preservation + * involved, as well as all the reads are happening through + * bpf_probe_read_kernel() calls using __builtin_preserve_access_index() to + * emit CO-RE relocations. + * + * N.B. Only up to 9 "field accessors" are supported, which should be more + * than enough for any practical purpose. + */ +#define BPF_CORE_READ(src, a, ...) \ + ({ \ + ___type((src), a, ##__VA_ARGS__) __r; \ + BPF_CORE_READ_INTO(&__r, (src), a, ##__VA_ARGS__); \ + __r; \ + }) + +#endif + diff --git a/tools/lib/bpf/bpf_endian.h b/tools/lib/bpf/bpf_endian.h new file mode 100644 index 000000000..ec9db4fec --- /dev/null +++ b/tools/lib/bpf/bpf_endian.h @@ -0,0 +1,99 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ +#ifndef __BPF_ENDIAN__ +#define __BPF_ENDIAN__ + +/* + * Isolate byte #n and put it into byte #m, for __u##b type. + * E.g., moving byte #6 (nnnnnnnn) into byte #1 (mmmmmmmm) for __u64: + * 1) xxxxxxxx nnnnnnnn xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx mmmmmmmm xxxxxxxx + * 2) nnnnnnnn xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx mmmmmmmm xxxxxxxx 00000000 + * 3) 00000000 00000000 00000000 00000000 00000000 00000000 00000000 nnnnnnnn + * 4) 00000000 00000000 00000000 00000000 00000000 00000000 nnnnnnnn 00000000 + */ +#define ___bpf_mvb(x, b, n, m) ((__u##b)(x) << (b-(n+1)*8) >> (b-8) << (m*8)) + +#define ___bpf_swab16(x) ((__u16)( \ + ___bpf_mvb(x, 16, 0, 1) | \ + ___bpf_mvb(x, 16, 1, 0))) + +#define ___bpf_swab32(x) ((__u32)( \ + ___bpf_mvb(x, 32, 0, 3) | \ + ___bpf_mvb(x, 32, 1, 2) | \ + ___bpf_mvb(x, 32, 2, 1) | \ + ___bpf_mvb(x, 32, 3, 0))) + +#define ___bpf_swab64(x) ((__u64)( \ + ___bpf_mvb(x, 64, 0, 7) | \ + ___bpf_mvb(x, 64, 1, 6) | \ + ___bpf_mvb(x, 64, 2, 5) | \ + ___bpf_mvb(x, 64, 3, 4) | \ + ___bpf_mvb(x, 64, 4, 3) | \ + ___bpf_mvb(x, 64, 5, 2) | \ + ___bpf_mvb(x, 64, 6, 1) | \ + ___bpf_mvb(x, 64, 7, 0))) + +/* LLVM's BPF target selects the endianness of the CPU + * it compiles on, or the user specifies (bpfel/bpfeb), + * respectively. The used __BYTE_ORDER__ is defined by + * the compiler, we cannot rely on __BYTE_ORDER from + * libc headers, since it doesn't reflect the actual + * requested byte order. + * + * Note, LLVM's BPF target has different __builtin_bswapX() + * semantics. It does map to BPF_ALU | BPF_END | BPF_TO_BE + * in bpfel and bpfeb case, which means below, that we map + * to cpu_to_be16(). We could use it unconditionally in BPF + * case, but better not rely on it, so that this header here + * can be used from application and BPF program side, which + * use different targets. + */ +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ +# define __bpf_ntohs(x) __builtin_bswap16(x) +# define __bpf_htons(x) __builtin_bswap16(x) +# define __bpf_constant_ntohs(x) ___bpf_swab16(x) +# define __bpf_constant_htons(x) ___bpf_swab16(x) +# define __bpf_ntohl(x) __builtin_bswap32(x) +# define __bpf_htonl(x) __builtin_bswap32(x) +# define __bpf_constant_ntohl(x) ___bpf_swab32(x) +# define __bpf_constant_htonl(x) ___bpf_swab32(x) +# define __bpf_be64_to_cpu(x) __builtin_bswap64(x) +# define __bpf_cpu_to_be64(x) __builtin_bswap64(x) +# define __bpf_constant_be64_to_cpu(x) ___bpf_swab64(x) +# define __bpf_constant_cpu_to_be64(x) ___bpf_swab64(x) +#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ +# define __bpf_ntohs(x) (x) +# define __bpf_htons(x) (x) +# define __bpf_constant_ntohs(x) (x) +# define __bpf_constant_htons(x) (x) +# define __bpf_ntohl(x) (x) +# define __bpf_htonl(x) (x) +# define __bpf_constant_ntohl(x) (x) +# define __bpf_constant_htonl(x) (x) +# define __bpf_be64_to_cpu(x) (x) +# define __bpf_cpu_to_be64(x) (x) +# define __bpf_constant_be64_to_cpu(x) (x) +# define __bpf_constant_cpu_to_be64(x) (x) +#else +# error "Fix your compiler's __BYTE_ORDER__?!" +#endif + +#define bpf_htons(x) \ + (__builtin_constant_p(x) ? \ + __bpf_constant_htons(x) : __bpf_htons(x)) +#define bpf_ntohs(x) \ + (__builtin_constant_p(x) ? \ + __bpf_constant_ntohs(x) : __bpf_ntohs(x)) +#define bpf_htonl(x) \ + (__builtin_constant_p(x) ? \ + __bpf_constant_htonl(x) : __bpf_htonl(x)) +#define bpf_ntohl(x) \ + (__builtin_constant_p(x) ? \ + __bpf_constant_ntohl(x) : __bpf_ntohl(x)) +#define bpf_cpu_to_be64(x) \ + (__builtin_constant_p(x) ? \ + __bpf_constant_cpu_to_be64(x) : __bpf_cpu_to_be64(x)) +#define bpf_be64_to_cpu(x) \ + (__builtin_constant_p(x) ? \ + __bpf_constant_be64_to_cpu(x) : __bpf_be64_to_cpu(x)) + +#endif /* __BPF_ENDIAN__ */ diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h new file mode 100644 index 000000000..1c389b0f5 --- /dev/null +++ b/tools/lib/bpf/bpf_helpers.h @@ -0,0 +1,136 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ +#ifndef __BPF_HELPERS__ +#define __BPF_HELPERS__ + +/* + * Note that bpf programs need to include either + * vmlinux.h (auto-generated from BTF) or linux/types.h + * in advance since bpf_helper_defs.h uses such types + * as __u64. + */ +#include "bpf_helper_defs.h" + +#define __uint(name, val) int (*name)[val] +#define __type(name, val) typeof(val) *name +#define __array(name, val) typeof(val) *name[] + +/* Helper macro to print out debug messages */ +#define bpf_printk(fmt, ...) \ +({ \ + char ____fmt[] = fmt; \ + bpf_trace_printk(____fmt, sizeof(____fmt), \ + ##__VA_ARGS__); \ +}) + +/* + * Helper macro to place programs, maps, license in + * different sections in elf_bpf file. Section names + * are interpreted by elf_bpf loader + */ +#define SEC(NAME) __attribute__((section(NAME), used)) + +#ifndef __always_inline +#define __always_inline __attribute__((always_inline)) +#endif +#ifndef __noinline +#define __noinline __attribute__((noinline)) +#endif +#ifndef __weak +#define __weak __attribute__((weak)) +#endif + +/* + * Helper macro to manipulate data structures + */ + +/* offsetof() definition that uses __builtin_offset() might not preserve field + * offset CO-RE relocation properly, so force-redefine offsetof() using + * old-school approach which works with CO-RE correctly + */ +#undef offsetof +#define offsetof(type, member) ((unsigned long)&((type *)0)->member) + +/* redefined container_of() to ensure we use the above offsetof() macro */ +#undef container_of +#define container_of(ptr, type, member) \ + ({ \ + void *__mptr = (void *)(ptr); \ + ((type *)(__mptr - offsetof(type, member))); \ + }) + +/* + * Helper macro to throw a compilation error if __bpf_unreachable() gets + * built into the resulting code. This works given BPF back end does not + * implement __builtin_trap(). This is useful to assert that certain paths + * of the program code are never used and hence eliminated by the compiler. + * + * For example, consider a switch statement that covers known cases used by + * the program. __bpf_unreachable() can then reside in the default case. If + * the program gets extended such that a case is not covered in the switch + * statement, then it will throw a build error due to the default case not + * being compiled out. + */ +#ifndef __bpf_unreachable +# define __bpf_unreachable() __builtin_trap() +#endif + +/* + * Helper function to perform a tail call with a constant/immediate map slot. + */ +#if __clang_major__ >= 8 && defined(__bpf__) +static __always_inline void +bpf_tail_call_static(void *ctx, const void *map, const __u32 slot) +{ + if (!__builtin_constant_p(slot)) + __bpf_unreachable(); + + /* + * Provide a hard guarantee that LLVM won't optimize setting r2 (map + * pointer) and r3 (constant map index) from _different paths_ ending + * up at the _same_ call insn as otherwise we won't be able to use the + * jmpq/nopl retpoline-free patching by the x86-64 JIT in the kernel + * given they mismatch. See also d2e4c1e6c294 ("bpf: Constant map key + * tracking for prog array pokes") for details on verifier tracking. + * + * Note on clobber list: we need to stay in-line with BPF calling + * convention, so even if we don't end up using r0, r4, r5, we need + * to mark them as clobber so that LLVM doesn't end up using them + * before / after the call. + */ + asm volatile("r1 = %[ctx]\n\t" + "r2 = %[map]\n\t" + "r3 = %[slot]\n\t" + "call 12" + :: [ctx]"r"(ctx), [map]"r"(map), [slot]"i"(slot) + : "r0", "r1", "r2", "r3", "r4", "r5"); +} +#endif + +/* + * Helper structure used by eBPF C program + * to describe BPF map attributes to libbpf loader + */ +struct bpf_map_def { + unsigned int type; + unsigned int key_size; + unsigned int value_size; + unsigned int max_entries; + unsigned int map_flags; +}; + +enum libbpf_pin_type { + LIBBPF_PIN_NONE, + /* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */ + LIBBPF_PIN_BY_NAME, +}; + +enum libbpf_tristate { + TRI_NO = 0, + TRI_YES = 1, + TRI_MODULE = 2, +}; + +#define __kconfig __attribute__((section(".kconfig"))) +#define __ksym __attribute__((section(".ksyms"))) + +#endif diff --git a/tools/lib/bpf/bpf_prog_linfo.c b/tools/lib/bpf/bpf_prog_linfo.c new file mode 100644 index 000000000..3ed1a27b5 --- /dev/null +++ b/tools/lib/bpf/bpf_prog_linfo.c @@ -0,0 +1,246 @@ +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) +/* Copyright (c) 2018 Facebook */ + +#include <string.h> +#include <stdlib.h> +#include <linux/err.h> +#include <linux/bpf.h> +#include "libbpf.h" +#include "libbpf_internal.h" + +struct bpf_prog_linfo { + void *raw_linfo; + void *raw_jited_linfo; + __u32 *nr_jited_linfo_per_func; + __u32 *jited_linfo_func_idx; + __u32 nr_linfo; + __u32 nr_jited_func; + __u32 rec_size; + __u32 jited_rec_size; +}; + +static int dissect_jited_func(struct bpf_prog_linfo *prog_linfo, + const __u64 *ksym_func, const __u32 *ksym_len) +{ + __u32 nr_jited_func, nr_linfo; + const void *raw_jited_linfo; + const __u64 *jited_linfo; + __u64 last_jited_linfo; + /* + * Index to raw_jited_linfo: + * i: Index for searching the next ksym_func + * prev_i: Index to the last found ksym_func + */ + __u32 i, prev_i; + __u32 f; /* Index to ksym_func */ + + raw_jited_linfo = prog_linfo->raw_jited_linfo; + jited_linfo = raw_jited_linfo; + if (ksym_func[0] != *jited_linfo) + goto errout; + + prog_linfo->jited_linfo_func_idx[0] = 0; + nr_jited_func = prog_linfo->nr_jited_func; + nr_linfo = prog_linfo->nr_linfo; + + for (prev_i = 0, i = 1, f = 1; + i < nr_linfo && f < nr_jited_func; + i++) { + raw_jited_linfo += prog_linfo->jited_rec_size; + last_jited_linfo = *jited_linfo; + jited_linfo = raw_jited_linfo; + + if (ksym_func[f] == *jited_linfo) { + prog_linfo->jited_linfo_func_idx[f] = i; + + /* Sanity check */ + if (last_jited_linfo - ksym_func[f - 1] + 1 > + ksym_len[f - 1]) + goto errout; + + prog_linfo->nr_jited_linfo_per_func[f - 1] = + i - prev_i; + prev_i = i; + + /* + * The ksym_func[f] is found in jited_linfo. + * Look for the next one. + */ + f++; + } else if (*jited_linfo <= last_jited_linfo) { + /* Ensure the addr is increasing _within_ a func */ + goto errout; + } + } + + if (f != nr_jited_func) + goto errout; + + prog_linfo->nr_jited_linfo_per_func[nr_jited_func - 1] = + nr_linfo - prev_i; + + return 0; + +errout: + return -EINVAL; +} + +void bpf_prog_linfo__free(struct bpf_prog_linfo *prog_linfo) +{ + if (!prog_linfo) + return; + + free(prog_linfo->raw_linfo); + free(prog_linfo->raw_jited_linfo); + free(prog_linfo->nr_jited_linfo_per_func); + free(prog_linfo->jited_linfo_func_idx); + free(prog_linfo); +} + +struct bpf_prog_linfo *bpf_prog_linfo__new(const struct bpf_prog_info *info) +{ + struct bpf_prog_linfo *prog_linfo; + __u32 nr_linfo, nr_jited_func; + __u64 data_sz; + + nr_linfo = info->nr_line_info; + + if (!nr_linfo) + return NULL; + + /* + * The min size that bpf_prog_linfo has to access for + * searching purpose. + */ + if (info->line_info_rec_size < + offsetof(struct bpf_line_info, file_name_off)) + return NULL; + + prog_linfo = calloc(1, sizeof(*prog_linfo)); + if (!prog_linfo) + return NULL; + + /* Copy xlated line_info */ + prog_linfo->nr_linfo = nr_linfo; + prog_linfo->rec_size = info->line_info_rec_size; + data_sz = (__u64)nr_linfo * prog_linfo->rec_size; + prog_linfo->raw_linfo = malloc(data_sz); + if (!prog_linfo->raw_linfo) + goto err_free; + memcpy(prog_linfo->raw_linfo, (void *)(long)info->line_info, data_sz); + + nr_jited_func = info->nr_jited_ksyms; + if (!nr_jited_func || + !info->jited_line_info || + info->nr_jited_line_info != nr_linfo || + info->jited_line_info_rec_size < sizeof(__u64) || + info->nr_jited_func_lens != nr_jited_func || + !info->jited_ksyms || + !info->jited_func_lens) + /* Not enough info to provide jited_line_info */ + return prog_linfo; + + /* Copy jited_line_info */ + prog_linfo->nr_jited_func = nr_jited_func; + prog_linfo->jited_rec_size = info->jited_line_info_rec_size; + data_sz = (__u64)nr_linfo * prog_linfo->jited_rec_size; + prog_linfo->raw_jited_linfo = malloc(data_sz); + if (!prog_linfo->raw_jited_linfo) + goto err_free; + memcpy(prog_linfo->raw_jited_linfo, + (void *)(long)info->jited_line_info, data_sz); + + /* Number of jited_line_info per jited func */ + prog_linfo->nr_jited_linfo_per_func = malloc(nr_jited_func * + sizeof(__u32)); + if (!prog_linfo->nr_jited_linfo_per_func) + goto err_free; + + /* + * For each jited func, + * the start idx to the "linfo" and "jited_linfo" array, + */ + prog_linfo->jited_linfo_func_idx = malloc(nr_jited_func * + sizeof(__u32)); + if (!prog_linfo->jited_linfo_func_idx) + goto err_free; + + if (dissect_jited_func(prog_linfo, + (__u64 *)(long)info->jited_ksyms, + (__u32 *)(long)info->jited_func_lens)) + goto err_free; + + return prog_linfo; + +err_free: + bpf_prog_linfo__free(prog_linfo); + return NULL; +} + +const struct bpf_line_info * +bpf_prog_linfo__lfind_addr_func(const struct bpf_prog_linfo *prog_linfo, + __u64 addr, __u32 func_idx, __u32 nr_skip) +{ + __u32 jited_rec_size, rec_size, nr_linfo, start, i; + const void *raw_jited_linfo, *raw_linfo; + const __u64 *jited_linfo; + + if (func_idx >= prog_linfo->nr_jited_func) + return NULL; + + nr_linfo = prog_linfo->nr_jited_linfo_per_func[func_idx]; + if (nr_skip >= nr_linfo) + return NULL; + + start = prog_linfo->jited_linfo_func_idx[func_idx] + nr_skip; + jited_rec_size = prog_linfo->jited_rec_size; + raw_jited_linfo = prog_linfo->raw_jited_linfo + + (start * jited_rec_size); + jited_linfo = raw_jited_linfo; + if (addr < *jited_linfo) + return NULL; + + nr_linfo -= nr_skip; + rec_size = prog_linfo->rec_size; + raw_linfo = prog_linfo->raw_linfo + (start * rec_size); + for (i = 0; i < nr_linfo; i++) { + if (addr < *jited_linfo) + break; + + raw_linfo += rec_size; + raw_jited_linfo += jited_rec_size; + jited_linfo = raw_jited_linfo; + } + + return raw_linfo - rec_size; +} + +const struct bpf_line_info * +bpf_prog_linfo__lfind(const struct bpf_prog_linfo *prog_linfo, + __u32 insn_off, __u32 nr_skip) +{ + const struct bpf_line_info *linfo; + __u32 rec_size, nr_linfo, i; + const void *raw_linfo; + + nr_linfo = prog_linfo->nr_linfo; + if (nr_skip >= nr_linfo) + return NULL; + + rec_size = prog_linfo->rec_size; + raw_linfo = prog_linfo->raw_linfo + (nr_skip * rec_size); + linfo = raw_linfo; + if (insn_off < linfo->insn_off) + return NULL; + + nr_linfo -= nr_skip; + for (i = 0; i < nr_linfo; i++) { + if (insn_off < linfo->insn_off) + break; + + raw_linfo += rec_size; + linfo = raw_linfo; + } + + return raw_linfo - rec_size; +} diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h new file mode 100644 index 000000000..1c2e91ee0 --- /dev/null +++ b/tools/lib/bpf/bpf_tracing.h @@ -0,0 +1,450 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ +#ifndef __BPF_TRACING_H__ +#define __BPF_TRACING_H__ + +/* Scan the ARCH passed in from ARCH env variable (see Makefile) */ +#if defined(__TARGET_ARCH_x86) + #define bpf_target_x86 + #define bpf_target_defined +#elif defined(__TARGET_ARCH_s390) + #define bpf_target_s390 + #define bpf_target_defined +#elif defined(__TARGET_ARCH_arm) + #define bpf_target_arm + #define bpf_target_defined +#elif defined(__TARGET_ARCH_arm64) + #define bpf_target_arm64 + #define bpf_target_defined +#elif defined(__TARGET_ARCH_mips) + #define bpf_target_mips + #define bpf_target_defined +#elif defined(__TARGET_ARCH_powerpc) + #define bpf_target_powerpc + #define bpf_target_defined +#elif defined(__TARGET_ARCH_sparc) + #define bpf_target_sparc + #define bpf_target_defined +#else + #undef bpf_target_defined +#endif + +/* Fall back to what the compiler says */ +#ifndef bpf_target_defined +#if defined(__x86_64__) + #define bpf_target_x86 +#elif defined(__s390__) + #define bpf_target_s390 +#elif defined(__arm__) + #define bpf_target_arm +#elif defined(__aarch64__) + #define bpf_target_arm64 +#elif defined(__mips__) + #define bpf_target_mips +#elif defined(__powerpc__) + #define bpf_target_powerpc +#elif defined(__sparc__) + #define bpf_target_sparc +#endif +#endif + +#if defined(bpf_target_x86) + +#if defined(__KERNEL__) || defined(__VMLINUX_H__) + +#define PT_REGS_PARM1(x) ((x)->di) +#define PT_REGS_PARM2(x) ((x)->si) +#define PT_REGS_PARM3(x) ((x)->dx) +#define PT_REGS_PARM4(x) ((x)->cx) +#define PT_REGS_PARM5(x) ((x)->r8) +#define PT_REGS_RET(x) ((x)->sp) +#define PT_REGS_FP(x) ((x)->bp) +#define PT_REGS_RC(x) ((x)->ax) +#define PT_REGS_SP(x) ((x)->sp) +#define PT_REGS_IP(x) ((x)->ip) + +#define PT_REGS_PARM1_CORE(x) BPF_CORE_READ((x), di) +#define PT_REGS_PARM2_CORE(x) BPF_CORE_READ((x), si) +#define PT_REGS_PARM3_CORE(x) BPF_CORE_READ((x), dx) +#define PT_REGS_PARM4_CORE(x) BPF_CORE_READ((x), cx) +#define PT_REGS_PARM5_CORE(x) BPF_CORE_READ((x), r8) +#define PT_REGS_RET_CORE(x) BPF_CORE_READ((x), sp) +#define PT_REGS_FP_CORE(x) BPF_CORE_READ((x), bp) +#define PT_REGS_RC_CORE(x) BPF_CORE_READ((x), ax) +#define PT_REGS_SP_CORE(x) BPF_CORE_READ((x), sp) +#define PT_REGS_IP_CORE(x) BPF_CORE_READ((x), ip) + +#else + +#ifdef __i386__ +/* i386 kernel is built with -mregparm=3 */ +#define PT_REGS_PARM1(x) ((x)->eax) +#define PT_REGS_PARM2(x) ((x)->edx) +#define PT_REGS_PARM3(x) ((x)->ecx) +#define PT_REGS_PARM4(x) 0 +#define PT_REGS_PARM5(x) 0 +#define PT_REGS_RET(x) ((x)->esp) +#define PT_REGS_FP(x) ((x)->ebp) +#define PT_REGS_RC(x) ((x)->eax) +#define PT_REGS_SP(x) ((x)->esp) +#define PT_REGS_IP(x) ((x)->eip) + +#define PT_REGS_PARM1_CORE(x) BPF_CORE_READ((x), eax) +#define PT_REGS_PARM2_CORE(x) BPF_CORE_READ((x), edx) +#define PT_REGS_PARM3_CORE(x) BPF_CORE_READ((x), ecx) +#define PT_REGS_PARM4_CORE(x) 0 +#define PT_REGS_PARM5_CORE(x) 0 +#define PT_REGS_RET_CORE(x) BPF_CORE_READ((x), esp) +#define PT_REGS_FP_CORE(x) BPF_CORE_READ((x), ebp) +#define PT_REGS_RC_CORE(x) BPF_CORE_READ((x), eax) +#define PT_REGS_SP_CORE(x) BPF_CORE_READ((x), esp) +#define PT_REGS_IP_CORE(x) BPF_CORE_READ((x), eip) + +#else + +#define PT_REGS_PARM1(x) ((x)->rdi) +#define PT_REGS_PARM2(x) ((x)->rsi) +#define PT_REGS_PARM3(x) ((x)->rdx) +#define PT_REGS_PARM4(x) ((x)->rcx) +#define PT_REGS_PARM5(x) ((x)->r8) +#define PT_REGS_RET(x) ((x)->rsp) +#define PT_REGS_FP(x) ((x)->rbp) +#define PT_REGS_RC(x) ((x)->rax) +#define PT_REGS_SP(x) ((x)->rsp) +#define PT_REGS_IP(x) ((x)->rip) + +#define PT_REGS_PARM1_CORE(x) BPF_CORE_READ((x), rdi) +#define PT_REGS_PARM2_CORE(x) BPF_CORE_READ((x), rsi) +#define PT_REGS_PARM3_CORE(x) BPF_CORE_READ((x), rdx) +#define PT_REGS_PARM4_CORE(x) BPF_CORE_READ((x), rcx) +#define PT_REGS_PARM5_CORE(x) BPF_CORE_READ((x), r8) +#define PT_REGS_RET_CORE(x) BPF_CORE_READ((x), rsp) +#define PT_REGS_FP_CORE(x) BPF_CORE_READ((x), rbp) +#define PT_REGS_RC_CORE(x) BPF_CORE_READ((x), rax) +#define PT_REGS_SP_CORE(x) BPF_CORE_READ((x), rsp) +#define PT_REGS_IP_CORE(x) BPF_CORE_READ((x), rip) + +#endif +#endif + +#elif defined(bpf_target_s390) + +/* s390 provides user_pt_regs instead of struct pt_regs to userspace */ +struct pt_regs; +#define PT_REGS_S390 const volatile user_pt_regs +#define PT_REGS_PARM1(x) (((PT_REGS_S390 *)(x))->gprs[2]) +#define PT_REGS_PARM2(x) (((PT_REGS_S390 *)(x))->gprs[3]) +#define PT_REGS_PARM3(x) (((PT_REGS_S390 *)(x))->gprs[4]) +#define PT_REGS_PARM4(x) (((PT_REGS_S390 *)(x))->gprs[5]) +#define PT_REGS_PARM5(x) (((PT_REGS_S390 *)(x))->gprs[6]) +#define PT_REGS_RET(x) (((PT_REGS_S390 *)(x))->gprs[14]) +/* Works only with CONFIG_FRAME_POINTER */ +#define PT_REGS_FP(x) (((PT_REGS_S390 *)(x))->gprs[11]) +#define PT_REGS_RC(x) (((PT_REGS_S390 *)(x))->gprs[2]) +#define PT_REGS_SP(x) (((PT_REGS_S390 *)(x))->gprs[15]) +#define PT_REGS_IP(x) (((PT_REGS_S390 *)(x))->psw.addr) + +#define PT_REGS_PARM1_CORE(x) BPF_CORE_READ((PT_REGS_S390 *)(x), gprs[2]) +#define PT_REGS_PARM2_CORE(x) BPF_CORE_READ((PT_REGS_S390 *)(x), gprs[3]) +#define PT_REGS_PARM3_CORE(x) BPF_CORE_READ((PT_REGS_S390 *)(x), gprs[4]) +#define PT_REGS_PARM4_CORE(x) BPF_CORE_READ((PT_REGS_S390 *)(x), gprs[5]) +#define PT_REGS_PARM5_CORE(x) BPF_CORE_READ((PT_REGS_S390 *)(x), gprs[6]) +#define PT_REGS_RET_CORE(x) BPF_CORE_READ((PT_REGS_S390 *)(x), gprs[14]) +#define PT_REGS_FP_CORE(x) BPF_CORE_READ((PT_REGS_S390 *)(x), gprs[11]) +#define PT_REGS_RC_CORE(x) BPF_CORE_READ((PT_REGS_S390 *)(x), gprs[2]) +#define PT_REGS_SP_CORE(x) BPF_CORE_READ((PT_REGS_S390 *)(x), gprs[15]) +#define PT_REGS_IP_CORE(x) BPF_CORE_READ((PT_REGS_S390 *)(x), psw.addr) + +#elif defined(bpf_target_arm) + +#define PT_REGS_PARM1(x) ((x)->uregs[0]) +#define PT_REGS_PARM2(x) ((x)->uregs[1]) +#define PT_REGS_PARM3(x) ((x)->uregs[2]) +#define PT_REGS_PARM4(x) ((x)->uregs[3]) +#define PT_REGS_PARM5(x) ((x)->uregs[4]) +#define PT_REGS_RET(x) ((x)->uregs[14]) +#define PT_REGS_FP(x) ((x)->uregs[11]) /* Works only with CONFIG_FRAME_POINTER */ +#define PT_REGS_RC(x) ((x)->uregs[0]) +#define PT_REGS_SP(x) ((x)->uregs[13]) +#define PT_REGS_IP(x) ((x)->uregs[12]) + +#define PT_REGS_PARM1_CORE(x) BPF_CORE_READ((x), uregs[0]) +#define PT_REGS_PARM2_CORE(x) BPF_CORE_READ((x), uregs[1]) +#define PT_REGS_PARM3_CORE(x) BPF_CORE_READ((x), uregs[2]) +#define PT_REGS_PARM4_CORE(x) BPF_CORE_READ((x), uregs[3]) +#define PT_REGS_PARM5_CORE(x) BPF_CORE_READ((x), uregs[4]) +#define PT_REGS_RET_CORE(x) BPF_CORE_READ((x), uregs[14]) +#define PT_REGS_FP_CORE(x) BPF_CORE_READ((x), uregs[11]) +#define PT_REGS_RC_CORE(x) BPF_CORE_READ((x), uregs[0]) +#define PT_REGS_SP_CORE(x) BPF_CORE_READ((x), uregs[13]) +#define PT_REGS_IP_CORE(x) BPF_CORE_READ((x), uregs[12]) + +#elif defined(bpf_target_arm64) + +/* arm64 provides struct user_pt_regs instead of struct pt_regs to userspace */ +struct pt_regs; +#define PT_REGS_ARM64 const volatile struct user_pt_regs +#define PT_REGS_PARM1(x) (((PT_REGS_ARM64 *)(x))->regs[0]) +#define PT_REGS_PARM2(x) (((PT_REGS_ARM64 *)(x))->regs[1]) +#define PT_REGS_PARM3(x) (((PT_REGS_ARM64 *)(x))->regs[2]) +#define PT_REGS_PARM4(x) (((PT_REGS_ARM64 *)(x))->regs[3]) +#define PT_REGS_PARM5(x) (((PT_REGS_ARM64 *)(x))->regs[4]) +#define PT_REGS_RET(x) (((PT_REGS_ARM64 *)(x))->regs[30]) +/* Works only with CONFIG_FRAME_POINTER */ +#define PT_REGS_FP(x) (((PT_REGS_ARM64 *)(x))->regs[29]) +#define PT_REGS_RC(x) (((PT_REGS_ARM64 *)(x))->regs[0]) +#define PT_REGS_SP(x) (((PT_REGS_ARM64 *)(x))->sp) +#define PT_REGS_IP(x) (((PT_REGS_ARM64 *)(x))->pc) + +#define PT_REGS_PARM1_CORE(x) BPF_CORE_READ((PT_REGS_ARM64 *)(x), regs[0]) +#define PT_REGS_PARM2_CORE(x) BPF_CORE_READ((PT_REGS_ARM64 *)(x), regs[1]) +#define PT_REGS_PARM3_CORE(x) BPF_CORE_READ((PT_REGS_ARM64 *)(x), regs[2]) +#define PT_REGS_PARM4_CORE(x) BPF_CORE_READ((PT_REGS_ARM64 *)(x), regs[3]) +#define PT_REGS_PARM5_CORE(x) BPF_CORE_READ((PT_REGS_ARM64 *)(x), regs[4]) +#define PT_REGS_RET_CORE(x) BPF_CORE_READ((PT_REGS_ARM64 *)(x), regs[30]) +#define PT_REGS_FP_CORE(x) BPF_CORE_READ((PT_REGS_ARM64 *)(x), regs[29]) +#define PT_REGS_RC_CORE(x) BPF_CORE_READ((PT_REGS_ARM64 *)(x), regs[0]) +#define PT_REGS_SP_CORE(x) BPF_CORE_READ((PT_REGS_ARM64 *)(x), sp) +#define PT_REGS_IP_CORE(x) BPF_CORE_READ((PT_REGS_ARM64 *)(x), pc) + +#elif defined(bpf_target_mips) + +#define PT_REGS_PARM1(x) ((x)->regs[4]) +#define PT_REGS_PARM2(x) ((x)->regs[5]) +#define PT_REGS_PARM3(x) ((x)->regs[6]) +#define PT_REGS_PARM4(x) ((x)->regs[7]) +#define PT_REGS_PARM5(x) ((x)->regs[8]) +#define PT_REGS_RET(x) ((x)->regs[31]) +#define PT_REGS_FP(x) ((x)->regs[30]) /* Works only with CONFIG_FRAME_POINTER */ +#define PT_REGS_RC(x) ((x)->regs[2]) +#define PT_REGS_SP(x) ((x)->regs[29]) +#define PT_REGS_IP(x) ((x)->cp0_epc) + +#define PT_REGS_PARM1_CORE(x) BPF_CORE_READ((x), regs[4]) +#define PT_REGS_PARM2_CORE(x) BPF_CORE_READ((x), regs[5]) +#define PT_REGS_PARM3_CORE(x) BPF_CORE_READ((x), regs[6]) +#define PT_REGS_PARM4_CORE(x) BPF_CORE_READ((x), regs[7]) +#define PT_REGS_PARM5_CORE(x) BPF_CORE_READ((x), regs[8]) +#define PT_REGS_RET_CORE(x) BPF_CORE_READ((x), regs[31]) +#define PT_REGS_FP_CORE(x) BPF_CORE_READ((x), regs[30]) +#define PT_REGS_RC_CORE(x) BPF_CORE_READ((x), regs[2]) +#define PT_REGS_SP_CORE(x) BPF_CORE_READ((x), regs[29]) +#define PT_REGS_IP_CORE(x) BPF_CORE_READ((x), cp0_epc) + +#elif defined(bpf_target_powerpc) + +#define PT_REGS_PARM1(x) ((x)->gpr[3]) +#define PT_REGS_PARM2(x) ((x)->gpr[4]) +#define PT_REGS_PARM3(x) ((x)->gpr[5]) +#define PT_REGS_PARM4(x) ((x)->gpr[6]) +#define PT_REGS_PARM5(x) ((x)->gpr[7]) +#define PT_REGS_RC(x) ((x)->gpr[3]) +#define PT_REGS_SP(x) ((x)->sp) +#define PT_REGS_IP(x) ((x)->nip) + +#define PT_REGS_PARM1_CORE(x) BPF_CORE_READ((x), gpr[3]) +#define PT_REGS_PARM2_CORE(x) BPF_CORE_READ((x), gpr[4]) +#define PT_REGS_PARM3_CORE(x) BPF_CORE_READ((x), gpr[5]) +#define PT_REGS_PARM4_CORE(x) BPF_CORE_READ((x), gpr[6]) +#define PT_REGS_PARM5_CORE(x) BPF_CORE_READ((x), gpr[7]) +#define PT_REGS_RC_CORE(x) BPF_CORE_READ((x), gpr[3]) +#define PT_REGS_SP_CORE(x) BPF_CORE_READ((x), sp) +#define PT_REGS_IP_CORE(x) BPF_CORE_READ((x), nip) + +#elif defined(bpf_target_sparc) + +#define PT_REGS_PARM1(x) ((x)->u_regs[UREG_I0]) +#define PT_REGS_PARM2(x) ((x)->u_regs[UREG_I1]) +#define PT_REGS_PARM3(x) ((x)->u_regs[UREG_I2]) +#define PT_REGS_PARM4(x) ((x)->u_regs[UREG_I3]) +#define PT_REGS_PARM5(x) ((x)->u_regs[UREG_I4]) +#define PT_REGS_RET(x) ((x)->u_regs[UREG_I7]) +#define PT_REGS_RC(x) ((x)->u_regs[UREG_I0]) +#define PT_REGS_SP(x) ((x)->u_regs[UREG_FP]) + +#define PT_REGS_PARM1_CORE(x) BPF_CORE_READ((x), u_regs[UREG_I0]) +#define PT_REGS_PARM2_CORE(x) BPF_CORE_READ((x), u_regs[UREG_I1]) +#define PT_REGS_PARM3_CORE(x) BPF_CORE_READ((x), u_regs[UREG_I2]) +#define PT_REGS_PARM4_CORE(x) BPF_CORE_READ((x), u_regs[UREG_I3]) +#define PT_REGS_PARM5_CORE(x) BPF_CORE_READ((x), u_regs[UREG_I4]) +#define PT_REGS_RET_CORE(x) BPF_CORE_READ((x), u_regs[UREG_I7]) +#define PT_REGS_RC_CORE(x) BPF_CORE_READ((x), u_regs[UREG_I0]) +#define PT_REGS_SP_CORE(x) BPF_CORE_READ((x), u_regs[UREG_FP]) + +/* Should this also be a bpf_target check for the sparc case? */ +#if defined(__arch64__) +#define PT_REGS_IP(x) ((x)->tpc) +#define PT_REGS_IP_CORE(x) BPF_CORE_READ((x), tpc) +#else +#define PT_REGS_IP(x) ((x)->pc) +#define PT_REGS_IP_CORE(x) BPF_CORE_READ((x), pc) +#endif + +#endif + +#if defined(bpf_target_powerpc) +#define BPF_KPROBE_READ_RET_IP(ip, ctx) ({ (ip) = (ctx)->link; }) +#define BPF_KRETPROBE_READ_RET_IP BPF_KPROBE_READ_RET_IP +#elif defined(bpf_target_sparc) +#define BPF_KPROBE_READ_RET_IP(ip, ctx) ({ (ip) = PT_REGS_RET(ctx); }) +#define BPF_KRETPROBE_READ_RET_IP BPF_KPROBE_READ_RET_IP +#else +#define BPF_KPROBE_READ_RET_IP(ip, ctx) \ + ({ bpf_probe_read_kernel(&(ip), sizeof(ip), (void *)PT_REGS_RET(ctx)); }) +#define BPF_KRETPROBE_READ_RET_IP(ip, ctx) \ + ({ bpf_probe_read_kernel(&(ip), sizeof(ip), \ + (void *)(PT_REGS_FP(ctx) + sizeof(ip))); }) +#endif + +#define ___bpf_concat(a, b) a ## b +#define ___bpf_apply(fn, n) ___bpf_concat(fn, n) +#define ___bpf_nth(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c, N, ...) N +#define ___bpf_narg(...) \ + ___bpf_nth(_, ##__VA_ARGS__, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) +#define ___bpf_empty(...) \ + ___bpf_nth(_, ##__VA_ARGS__, N, N, N, N, N, N, N, N, N, N, 0) + +#define ___bpf_ctx_cast0() ctx +#define ___bpf_ctx_cast1(x) ___bpf_ctx_cast0(), (void *)ctx[0] +#define ___bpf_ctx_cast2(x, args...) ___bpf_ctx_cast1(args), (void *)ctx[1] +#define ___bpf_ctx_cast3(x, args...) ___bpf_ctx_cast2(args), (void *)ctx[2] +#define ___bpf_ctx_cast4(x, args...) ___bpf_ctx_cast3(args), (void *)ctx[3] +#define ___bpf_ctx_cast5(x, args...) ___bpf_ctx_cast4(args), (void *)ctx[4] +#define ___bpf_ctx_cast6(x, args...) ___bpf_ctx_cast5(args), (void *)ctx[5] +#define ___bpf_ctx_cast7(x, args...) ___bpf_ctx_cast6(args), (void *)ctx[6] +#define ___bpf_ctx_cast8(x, args...) ___bpf_ctx_cast7(args), (void *)ctx[7] +#define ___bpf_ctx_cast9(x, args...) ___bpf_ctx_cast8(args), (void *)ctx[8] +#define ___bpf_ctx_cast10(x, args...) ___bpf_ctx_cast9(args), (void *)ctx[9] +#define ___bpf_ctx_cast11(x, args...) ___bpf_ctx_cast10(args), (void *)ctx[10] +#define ___bpf_ctx_cast12(x, args...) ___bpf_ctx_cast11(args), (void *)ctx[11] +#define ___bpf_ctx_cast(args...) \ + ___bpf_apply(___bpf_ctx_cast, ___bpf_narg(args))(args) + +/* + * BPF_PROG is a convenience wrapper for generic tp_btf/fentry/fexit and + * similar kinds of BPF programs, that accept input arguments as a single + * pointer to untyped u64 array, where each u64 can actually be a typed + * pointer or integer of different size. Instead of requring user to write + * manual casts and work with array elements by index, BPF_PROG macro + * allows user to declare a list of named and typed input arguments in the + * same syntax as for normal C function. All the casting is hidden and + * performed transparently, while user code can just assume working with + * function arguments of specified type and name. + * + * Original raw context argument is preserved as well as 'ctx' argument. + * This is useful when using BPF helpers that expect original context + * as one of the parameters (e.g., for bpf_perf_event_output()). + */ +#define BPF_PROG(name, args...) \ +name(unsigned long long *ctx); \ +static __attribute__((always_inline)) typeof(name(0)) \ +____##name(unsigned long long *ctx, ##args); \ +typeof(name(0)) name(unsigned long long *ctx) \ +{ \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \ + return ____##name(___bpf_ctx_cast(args)); \ + _Pragma("GCC diagnostic pop") \ +} \ +static __attribute__((always_inline)) typeof(name(0)) \ +____##name(unsigned long long *ctx, ##args) + +struct pt_regs; + +#define ___bpf_kprobe_args0() ctx +#define ___bpf_kprobe_args1(x) \ + ___bpf_kprobe_args0(), (void *)PT_REGS_PARM1(ctx) +#define ___bpf_kprobe_args2(x, args...) \ + ___bpf_kprobe_args1(args), (void *)PT_REGS_PARM2(ctx) +#define ___bpf_kprobe_args3(x, args...) \ + ___bpf_kprobe_args2(args), (void *)PT_REGS_PARM3(ctx) +#define ___bpf_kprobe_args4(x, args...) \ + ___bpf_kprobe_args3(args), (void *)PT_REGS_PARM4(ctx) +#define ___bpf_kprobe_args5(x, args...) \ + ___bpf_kprobe_args4(args), (void *)PT_REGS_PARM5(ctx) +#define ___bpf_kprobe_args(args...) \ + ___bpf_apply(___bpf_kprobe_args, ___bpf_narg(args))(args) + +/* + * BPF_KPROBE serves the same purpose for kprobes as BPF_PROG for + * tp_btf/fentry/fexit BPF programs. It hides the underlying platform-specific + * low-level way of getting kprobe input arguments from struct pt_regs, and + * provides a familiar typed and named function arguments syntax and + * semantics of accessing kprobe input paremeters. + * + * Original struct pt_regs* context is preserved as 'ctx' argument. This might + * be necessary when using BPF helpers like bpf_perf_event_output(). + */ +#define BPF_KPROBE(name, args...) \ +name(struct pt_regs *ctx); \ +static __attribute__((always_inline)) typeof(name(0)) \ +____##name(struct pt_regs *ctx, ##args); \ +typeof(name(0)) name(struct pt_regs *ctx) \ +{ \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \ + return ____##name(___bpf_kprobe_args(args)); \ + _Pragma("GCC diagnostic pop") \ +} \ +static __attribute__((always_inline)) typeof(name(0)) \ +____##name(struct pt_regs *ctx, ##args) + +#define ___bpf_kretprobe_args0() ctx +#define ___bpf_kretprobe_args1(x) \ + ___bpf_kretprobe_args0(), (void *)PT_REGS_RC(ctx) +#define ___bpf_kretprobe_args(args...) \ + ___bpf_apply(___bpf_kretprobe_args, ___bpf_narg(args))(args) + +/* + * BPF_KRETPROBE is similar to BPF_KPROBE, except, it only provides optional + * return value (in addition to `struct pt_regs *ctx`), but no input + * arguments, because they will be clobbered by the time probed function + * returns. + */ +#define BPF_KRETPROBE(name, args...) \ +name(struct pt_regs *ctx); \ +static __attribute__((always_inline)) typeof(name(0)) \ +____##name(struct pt_regs *ctx, ##args); \ +typeof(name(0)) name(struct pt_regs *ctx) \ +{ \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \ + return ____##name(___bpf_kretprobe_args(args)); \ + _Pragma("GCC diagnostic pop") \ +} \ +static __always_inline typeof(name(0)) ____##name(struct pt_regs *ctx, ##args) + +#define ___bpf_fill0(arr, p, x) do {} while (0) +#define ___bpf_fill1(arr, p, x) arr[p] = x +#define ___bpf_fill2(arr, p, x, args...) arr[p] = x; ___bpf_fill1(arr, p + 1, args) +#define ___bpf_fill3(arr, p, x, args...) arr[p] = x; ___bpf_fill2(arr, p + 1, args) +#define ___bpf_fill4(arr, p, x, args...) arr[p] = x; ___bpf_fill3(arr, p + 1, args) +#define ___bpf_fill5(arr, p, x, args...) arr[p] = x; ___bpf_fill4(arr, p + 1, args) +#define ___bpf_fill6(arr, p, x, args...) arr[p] = x; ___bpf_fill5(arr, p + 1, args) +#define ___bpf_fill7(arr, p, x, args...) arr[p] = x; ___bpf_fill6(arr, p + 1, args) +#define ___bpf_fill8(arr, p, x, args...) arr[p] = x; ___bpf_fill7(arr, p + 1, args) +#define ___bpf_fill9(arr, p, x, args...) arr[p] = x; ___bpf_fill8(arr, p + 1, args) +#define ___bpf_fill10(arr, p, x, args...) arr[p] = x; ___bpf_fill9(arr, p + 1, args) +#define ___bpf_fill11(arr, p, x, args...) arr[p] = x; ___bpf_fill10(arr, p + 1, args) +#define ___bpf_fill12(arr, p, x, args...) arr[p] = x; ___bpf_fill11(arr, p + 1, args) +#define ___bpf_fill(arr, args...) \ + ___bpf_apply(___bpf_fill, ___bpf_narg(args))(arr, 0, args) + +/* + * BPF_SEQ_PRINTF to wrap bpf_seq_printf to-be-printed values + * in a structure. + */ +#define BPF_SEQ_PRINTF(seq, fmt, args...) \ +({ \ + static const char ___fmt[] = fmt; \ + unsigned long long ___param[___bpf_narg(args)]; \ + \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \ + ___bpf_fill(___param, args); \ + _Pragma("GCC diagnostic pop") \ + \ + bpf_seq_printf(seq, ___fmt, sizeof(___fmt), \ + ___param, sizeof(___param)); \ +}) + +#endif diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c new file mode 100644 index 000000000..f7c48b1fb --- /dev/null +++ b/tools/lib/bpf/btf.c @@ -0,0 +1,4484 @@ +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) +/* Copyright (c) 2018 Facebook */ + +#include <byteswap.h> +#include <endian.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <fcntl.h> +#include <unistd.h> +#include <errno.h> +#include <sys/utsname.h> +#include <sys/param.h> +#include <sys/stat.h> +#include <linux/kernel.h> +#include <linux/err.h> +#include <linux/btf.h> +#include <gelf.h> +#include "btf.h" +#include "bpf.h" +#include "libbpf.h" +#include "libbpf_internal.h" +#include "hashmap.h" + +#define BTF_MAX_NR_TYPES 0x7fffffffU +#define BTF_MAX_STR_OFFSET 0x7fffffffU + +static struct btf_type btf_void; + +struct btf { + /* raw BTF data in native endianness */ + void *raw_data; + /* raw BTF data in non-native endianness */ + void *raw_data_swapped; + __u32 raw_size; + /* whether target endianness differs from the native one */ + bool swapped_endian; + + /* + * When BTF is loaded from an ELF or raw memory it is stored + * in a contiguous memory block. The hdr, type_data, and, strs_data + * point inside that memory region to their respective parts of BTF + * representation: + * + * +--------------------------------+ + * | Header | Types | Strings | + * +--------------------------------+ + * ^ ^ ^ + * | | | + * hdr | | + * types_data-+ | + * strs_data------------+ + * + * If BTF data is later modified, e.g., due to types added or + * removed, BTF deduplication performed, etc, this contiguous + * representation is broken up into three independently allocated + * memory regions to be able to modify them independently. + * raw_data is nulled out at that point, but can be later allocated + * and cached again if user calls btf__get_raw_data(), at which point + * raw_data will contain a contiguous copy of header, types, and + * strings: + * + * +----------+ +---------+ +-----------+ + * | Header | | Types | | Strings | + * +----------+ +---------+ +-----------+ + * ^ ^ ^ + * | | | + * hdr | | + * types_data----+ | + * strs_data------------------+ + * + * +----------+---------+-----------+ + * | Header | Types | Strings | + * raw_data----->+----------+---------+-----------+ + */ + struct btf_header *hdr; + + void *types_data; + size_t types_data_cap; /* used size stored in hdr->type_len */ + + /* type ID to `struct btf_type *` lookup index */ + __u32 *type_offs; + size_t type_offs_cap; + __u32 nr_types; + + void *strs_data; + size_t strs_data_cap; /* used size stored in hdr->str_len */ + + /* lookup index for each unique string in strings section */ + struct hashmap *strs_hash; + /* whether strings are already deduplicated */ + bool strs_deduped; + /* BTF object FD, if loaded into kernel */ + int fd; + + /* Pointer size (in bytes) for a target architecture of this BTF */ + int ptr_sz; +}; + +static inline __u64 ptr_to_u64(const void *ptr) +{ + return (__u64) (unsigned long) ptr; +} + +/* Ensure given dynamically allocated memory region pointed to by *data* with + * capacity of *cap_cnt* elements each taking *elem_sz* bytes has enough + * memory to accomodate *add_cnt* new elements, assuming *cur_cnt* elements + * are already used. At most *max_cnt* elements can be ever allocated. + * If necessary, memory is reallocated and all existing data is copied over, + * new pointer to the memory region is stored at *data, new memory region + * capacity (in number of elements) is stored in *cap. + * On success, memory pointer to the beginning of unused memory is returned. + * On error, NULL is returned. + */ +void *btf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, + size_t cur_cnt, size_t max_cnt, size_t add_cnt) +{ + size_t new_cnt; + void *new_data; + + if (cur_cnt + add_cnt <= *cap_cnt) + return *data + cur_cnt * elem_sz; + + /* requested more than the set limit */ + if (cur_cnt + add_cnt > max_cnt) + return NULL; + + new_cnt = *cap_cnt; + new_cnt += new_cnt / 4; /* expand by 25% */ + if (new_cnt < 16) /* but at least 16 elements */ + new_cnt = 16; + if (new_cnt > max_cnt) /* but not exceeding a set limit */ + new_cnt = max_cnt; + if (new_cnt < cur_cnt + add_cnt) /* also ensure we have enough memory */ + new_cnt = cur_cnt + add_cnt; + + new_data = libbpf_reallocarray(*data, new_cnt, elem_sz); + if (!new_data) + return NULL; + + /* zero out newly allocated portion of memory */ + memset(new_data + (*cap_cnt) * elem_sz, 0, (new_cnt - *cap_cnt) * elem_sz); + + *data = new_data; + *cap_cnt = new_cnt; + return new_data + cur_cnt * elem_sz; +} + +/* Ensure given dynamically allocated memory region has enough allocated space + * to accommodate *need_cnt* elements of size *elem_sz* bytes each + */ +int btf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt) +{ + void *p; + + if (need_cnt <= *cap_cnt) + return 0; + + p = btf_add_mem(data, cap_cnt, elem_sz, *cap_cnt, SIZE_MAX, need_cnt - *cap_cnt); + if (!p) + return -ENOMEM; + + return 0; +} + +static int btf_add_type_idx_entry(struct btf *btf, __u32 type_off) +{ + __u32 *p; + + p = btf_add_mem((void **)&btf->type_offs, &btf->type_offs_cap, sizeof(__u32), + btf->nr_types + 1, BTF_MAX_NR_TYPES, 1); + if (!p) + return -ENOMEM; + + *p = type_off; + return 0; +} + +static void btf_bswap_hdr(struct btf_header *h) +{ + h->magic = bswap_16(h->magic); + h->hdr_len = bswap_32(h->hdr_len); + h->type_off = bswap_32(h->type_off); + h->type_len = bswap_32(h->type_len); + h->str_off = bswap_32(h->str_off); + h->str_len = bswap_32(h->str_len); +} + +static int btf_parse_hdr(struct btf *btf) +{ + struct btf_header *hdr = btf->hdr; + __u32 meta_left; + + if (btf->raw_size < sizeof(struct btf_header)) { + pr_debug("BTF header not found\n"); + return -EINVAL; + } + + if (hdr->magic == bswap_16(BTF_MAGIC)) { + btf->swapped_endian = true; + if (bswap_32(hdr->hdr_len) != sizeof(struct btf_header)) { + pr_warn("Can't load BTF with non-native endianness due to unsupported header length %u\n", + bswap_32(hdr->hdr_len)); + return -ENOTSUP; + } + btf_bswap_hdr(hdr); + } else if (hdr->magic != BTF_MAGIC) { + pr_debug("Invalid BTF magic: %x\n", hdr->magic); + return -EINVAL; + } + + if (btf->raw_size < hdr->hdr_len) { + pr_debug("BTF header len %u larger than data size %u\n", + hdr->hdr_len, btf->raw_size); + return -EINVAL; + } + + meta_left = btf->raw_size - hdr->hdr_len; + if (meta_left < (long long)hdr->str_off + hdr->str_len) { + pr_debug("Invalid BTF total size: %u\n", btf->raw_size); + return -EINVAL; + } + + if ((long long)hdr->type_off + hdr->type_len > hdr->str_off) { + pr_debug("Invalid BTF data sections layout: type data at %u + %u, strings data at %u + %u\n", + hdr->type_off, hdr->type_len, hdr->str_off, hdr->str_len); + return -EINVAL; + } + + if (hdr->type_off % 4) { + pr_debug("BTF type section is not aligned to 4 bytes\n"); + return -EINVAL; + } + + return 0; +} + +static int btf_parse_str_sec(struct btf *btf) +{ + const struct btf_header *hdr = btf->hdr; + const char *start = btf->strs_data; + const char *end = start + btf->hdr->str_len; + + if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_STR_OFFSET || + start[0] || end[-1]) { + pr_debug("Invalid BTF string section\n"); + return -EINVAL; + } + + return 0; +} + +static int btf_type_size(const struct btf_type *t) +{ + const int base_size = sizeof(struct btf_type); + __u16 vlen = btf_vlen(t); + + switch (btf_kind(t)) { + case BTF_KIND_FWD: + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + return base_size; + case BTF_KIND_INT: + return base_size + sizeof(__u32); + case BTF_KIND_ENUM: + return base_size + vlen * sizeof(struct btf_enum); + case BTF_KIND_ARRAY: + return base_size + sizeof(struct btf_array); + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + return base_size + vlen * sizeof(struct btf_member); + case BTF_KIND_FUNC_PROTO: + return base_size + vlen * sizeof(struct btf_param); + case BTF_KIND_VAR: + return base_size + sizeof(struct btf_var); + case BTF_KIND_DATASEC: + return base_size + vlen * sizeof(struct btf_var_secinfo); + default: + pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t)); + return -EINVAL; + } +} + +static void btf_bswap_type_base(struct btf_type *t) +{ + t->name_off = bswap_32(t->name_off); + t->info = bswap_32(t->info); + t->type = bswap_32(t->type); +} + +static int btf_bswap_type_rest(struct btf_type *t) +{ + struct btf_var_secinfo *v; + struct btf_member *m; + struct btf_array *a; + struct btf_param *p; + struct btf_enum *e; + __u16 vlen = btf_vlen(t); + int i; + + switch (btf_kind(t)) { + case BTF_KIND_FWD: + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + return 0; + case BTF_KIND_INT: + *(__u32 *)(t + 1) = bswap_32(*(__u32 *)(t + 1)); + return 0; + case BTF_KIND_ENUM: + for (i = 0, e = btf_enum(t); i < vlen; i++, e++) { + e->name_off = bswap_32(e->name_off); + e->val = bswap_32(e->val); + } + return 0; + case BTF_KIND_ARRAY: + a = btf_array(t); + a->type = bswap_32(a->type); + a->index_type = bswap_32(a->index_type); + a->nelems = bswap_32(a->nelems); + return 0; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + for (i = 0, m = btf_members(t); i < vlen; i++, m++) { + m->name_off = bswap_32(m->name_off); + m->type = bswap_32(m->type); + m->offset = bswap_32(m->offset); + } + return 0; + case BTF_KIND_FUNC_PROTO: + for (i = 0, p = btf_params(t); i < vlen; i++, p++) { + p->name_off = bswap_32(p->name_off); + p->type = bswap_32(p->type); + } + return 0; + case BTF_KIND_VAR: + btf_var(t)->linkage = bswap_32(btf_var(t)->linkage); + return 0; + case BTF_KIND_DATASEC: + for (i = 0, v = btf_var_secinfos(t); i < vlen; i++, v++) { + v->type = bswap_32(v->type); + v->offset = bswap_32(v->offset); + v->size = bswap_32(v->size); + } + return 0; + default: + pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t)); + return -EINVAL; + } +} + +static int btf_parse_type_sec(struct btf *btf) +{ + struct btf_header *hdr = btf->hdr; + void *next_type = btf->types_data; + void *end_type = next_type + hdr->type_len; + int err, i = 0, type_size; + + /* VOID (type_id == 0) is specially handled by btf__get_type_by_id(), + * so ensure we can never properly use its offset from index by + * setting it to a large value + */ + err = btf_add_type_idx_entry(btf, UINT_MAX); + if (err) + return err; + + while (next_type + sizeof(struct btf_type) <= end_type) { + i++; + + if (btf->swapped_endian) + btf_bswap_type_base(next_type); + + type_size = btf_type_size(next_type); + if (type_size < 0) + return type_size; + if (next_type + type_size > end_type) { + pr_warn("BTF type [%d] is malformed\n", i); + return -EINVAL; + } + + if (btf->swapped_endian && btf_bswap_type_rest(next_type)) + return -EINVAL; + + err = btf_add_type_idx_entry(btf, next_type - btf->types_data); + if (err) + return err; + + next_type += type_size; + btf->nr_types++; + } + + if (next_type != end_type) { + pr_warn("BTF types data is malformed\n"); + return -EINVAL; + } + + return 0; +} + +__u32 btf__get_nr_types(const struct btf *btf) +{ + return btf->nr_types; +} + +/* internal helper returning non-const pointer to a type */ +static struct btf_type *btf_type_by_id(struct btf *btf, __u32 type_id) +{ + if (type_id == 0) + return &btf_void; + + return btf->types_data + btf->type_offs[type_id]; +} + +const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id) +{ + if (type_id > btf->nr_types) + return NULL; + return btf_type_by_id((struct btf *)btf, type_id); +} + +static int determine_ptr_size(const struct btf *btf) +{ + const struct btf_type *t; + const char *name; + int i; + + for (i = 1; i <= btf->nr_types; i++) { + t = btf__type_by_id(btf, i); + if (!btf_is_int(t)) + continue; + + name = btf__name_by_offset(btf, t->name_off); + if (!name) + continue; + + if (strcmp(name, "long int") == 0 || + strcmp(name, "long unsigned int") == 0) { + if (t->size != 4 && t->size != 8) + continue; + return t->size; + } + } + + return -1; +} + +static size_t btf_ptr_sz(const struct btf *btf) +{ + if (!btf->ptr_sz) + ((struct btf *)btf)->ptr_sz = determine_ptr_size(btf); + return btf->ptr_sz < 0 ? sizeof(void *) : btf->ptr_sz; +} + +/* Return pointer size this BTF instance assumes. The size is heuristically + * determined by looking for 'long' or 'unsigned long' integer type and + * recording its size in bytes. If BTF type information doesn't have any such + * type, this function returns 0. In the latter case, native architecture's + * pointer size is assumed, so will be either 4 or 8, depending on + * architecture that libbpf was compiled for. It's possible to override + * guessed value by using btf__set_pointer_size() API. + */ +size_t btf__pointer_size(const struct btf *btf) +{ + if (!btf->ptr_sz) + ((struct btf *)btf)->ptr_sz = determine_ptr_size(btf); + + if (btf->ptr_sz < 0) + /* not enough BTF type info to guess */ + return 0; + + return btf->ptr_sz; +} + +/* Override or set pointer size in bytes. Only values of 4 and 8 are + * supported. + */ +int btf__set_pointer_size(struct btf *btf, size_t ptr_sz) +{ + if (ptr_sz != 4 && ptr_sz != 8) + return -EINVAL; + btf->ptr_sz = ptr_sz; + return 0; +} + +static bool is_host_big_endian(void) +{ +#if __BYTE_ORDER == __LITTLE_ENDIAN + return false; +#elif __BYTE_ORDER == __BIG_ENDIAN + return true; +#else +# error "Unrecognized __BYTE_ORDER__" +#endif +} + +enum btf_endianness btf__endianness(const struct btf *btf) +{ + if (is_host_big_endian()) + return btf->swapped_endian ? BTF_LITTLE_ENDIAN : BTF_BIG_ENDIAN; + else + return btf->swapped_endian ? BTF_BIG_ENDIAN : BTF_LITTLE_ENDIAN; +} + +int btf__set_endianness(struct btf *btf, enum btf_endianness endian) +{ + if (endian != BTF_LITTLE_ENDIAN && endian != BTF_BIG_ENDIAN) + return -EINVAL; + + btf->swapped_endian = is_host_big_endian() != (endian == BTF_BIG_ENDIAN); + if (!btf->swapped_endian) { + free(btf->raw_data_swapped); + btf->raw_data_swapped = NULL; + } + return 0; +} + +static bool btf_type_is_void(const struct btf_type *t) +{ + return t == &btf_void || btf_is_fwd(t); +} + +static bool btf_type_is_void_or_null(const struct btf_type *t) +{ + return !t || btf_type_is_void(t); +} + +#define MAX_RESOLVE_DEPTH 32 + +__s64 btf__resolve_size(const struct btf *btf, __u32 type_id) +{ + const struct btf_array *array; + const struct btf_type *t; + __u32 nelems = 1; + __s64 size = -1; + int i; + + t = btf__type_by_id(btf, type_id); + for (i = 0; i < MAX_RESOLVE_DEPTH && !btf_type_is_void_or_null(t); + i++) { + switch (btf_kind(t)) { + case BTF_KIND_INT: + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + case BTF_KIND_ENUM: + case BTF_KIND_DATASEC: + size = t->size; + goto done; + case BTF_KIND_PTR: + size = btf_ptr_sz(btf); + goto done; + case BTF_KIND_TYPEDEF: + case BTF_KIND_VOLATILE: + case BTF_KIND_CONST: + case BTF_KIND_RESTRICT: + case BTF_KIND_VAR: + type_id = t->type; + break; + case BTF_KIND_ARRAY: + array = btf_array(t); + if (nelems && array->nelems > UINT32_MAX / nelems) + return -E2BIG; + nelems *= array->nelems; + type_id = array->type; + break; + default: + return -EINVAL; + } + + t = btf__type_by_id(btf, type_id); + } + +done: + if (size < 0) + return -EINVAL; + if (nelems && size > UINT32_MAX / nelems) + return -E2BIG; + + return nelems * size; +} + +int btf__align_of(const struct btf *btf, __u32 id) +{ + const struct btf_type *t = btf__type_by_id(btf, id); + __u16 kind = btf_kind(t); + + switch (kind) { + case BTF_KIND_INT: + case BTF_KIND_ENUM: + return min(btf_ptr_sz(btf), (size_t)t->size); + case BTF_KIND_PTR: + return btf_ptr_sz(btf); + case BTF_KIND_TYPEDEF: + case BTF_KIND_VOLATILE: + case BTF_KIND_CONST: + case BTF_KIND_RESTRICT: + return btf__align_of(btf, t->type); + case BTF_KIND_ARRAY: + return btf__align_of(btf, btf_array(t)->type); + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: { + const struct btf_member *m = btf_members(t); + __u16 vlen = btf_vlen(t); + int i, max_align = 1, align; + + for (i = 0; i < vlen; i++, m++) { + align = btf__align_of(btf, m->type); + if (align <= 0) + return align; + max_align = max(max_align, align); + + /* if field offset isn't aligned according to field + * type's alignment, then struct must be packed + */ + if (btf_member_bitfield_size(t, i) == 0 && + (m->offset % (8 * align)) != 0) + return 1; + } + + /* if struct/union size isn't a multiple of its alignment, + * then struct must be packed + */ + if ((t->size % max_align) != 0) + return 1; + + return max_align; + } + default: + pr_warn("unsupported BTF_KIND:%u\n", btf_kind(t)); + return 0; + } +} + +int btf__resolve_type(const struct btf *btf, __u32 type_id) +{ + const struct btf_type *t; + int depth = 0; + + t = btf__type_by_id(btf, type_id); + while (depth < MAX_RESOLVE_DEPTH && + !btf_type_is_void_or_null(t) && + (btf_is_mod(t) || btf_is_typedef(t) || btf_is_var(t))) { + type_id = t->type; + t = btf__type_by_id(btf, type_id); + depth++; + } + + if (depth == MAX_RESOLVE_DEPTH || btf_type_is_void_or_null(t)) + return -EINVAL; + + return type_id; +} + +__s32 btf__find_by_name(const struct btf *btf, const char *type_name) +{ + __u32 i; + + if (!strcmp(type_name, "void")) + return 0; + + for (i = 1; i <= btf->nr_types; i++) { + const struct btf_type *t = btf__type_by_id(btf, i); + const char *name = btf__name_by_offset(btf, t->name_off); + + if (name && !strcmp(type_name, name)) + return i; + } + + return -ENOENT; +} + +__s32 btf__find_by_name_kind(const struct btf *btf, const char *type_name, + __u32 kind) +{ + __u32 i; + + if (kind == BTF_KIND_UNKN || !strcmp(type_name, "void")) + return 0; + + for (i = 1; i <= btf->nr_types; i++) { + const struct btf_type *t = btf__type_by_id(btf, i); + const char *name; + + if (btf_kind(t) != kind) + continue; + name = btf__name_by_offset(btf, t->name_off); + if (name && !strcmp(type_name, name)) + return i; + } + + return -ENOENT; +} + +static bool btf_is_modifiable(const struct btf *btf) +{ + return (void *)btf->hdr != btf->raw_data; +} + +void btf__free(struct btf *btf) +{ + if (IS_ERR_OR_NULL(btf)) + return; + + if (btf->fd >= 0) + close(btf->fd); + + if (btf_is_modifiable(btf)) { + /* if BTF was modified after loading, it will have a split + * in-memory representation for header, types, and strings + * sections, so we need to free all of them individually. It + * might still have a cached contiguous raw data present, + * which will be unconditionally freed below. + */ + free(btf->hdr); + free(btf->types_data); + free(btf->strs_data); + } + free(btf->raw_data); + free(btf->raw_data_swapped); + free(btf->type_offs); + free(btf); +} + +struct btf *btf__new_empty(void) +{ + struct btf *btf; + + btf = calloc(1, sizeof(*btf)); + if (!btf) + return ERR_PTR(-ENOMEM); + + btf->fd = -1; + btf->ptr_sz = sizeof(void *); + btf->swapped_endian = false; + + /* +1 for empty string at offset 0 */ + btf->raw_size = sizeof(struct btf_header) + 1; + btf->raw_data = calloc(1, btf->raw_size); + if (!btf->raw_data) { + free(btf); + return ERR_PTR(-ENOMEM); + } + + btf->hdr = btf->raw_data; + btf->hdr->hdr_len = sizeof(struct btf_header); + btf->hdr->magic = BTF_MAGIC; + btf->hdr->version = BTF_VERSION; + + btf->types_data = btf->raw_data + btf->hdr->hdr_len; + btf->strs_data = btf->raw_data + btf->hdr->hdr_len; + btf->hdr->str_len = 1; /* empty string at offset 0 */ + + return btf; +} + +struct btf *btf__new(const void *data, __u32 size) +{ + struct btf *btf; + int err; + + btf = calloc(1, sizeof(struct btf)); + if (!btf) + return ERR_PTR(-ENOMEM); + + btf->raw_data = malloc(size); + if (!btf->raw_data) { + err = -ENOMEM; + goto done; + } + memcpy(btf->raw_data, data, size); + btf->raw_size = size; + + btf->hdr = btf->raw_data; + err = btf_parse_hdr(btf); + if (err) + goto done; + + btf->strs_data = btf->raw_data + btf->hdr->hdr_len + btf->hdr->str_off; + btf->types_data = btf->raw_data + btf->hdr->hdr_len + btf->hdr->type_off; + + err = btf_parse_str_sec(btf); + err = err ?: btf_parse_type_sec(btf); + if (err) + goto done; + + btf->fd = -1; + +done: + if (err) { + btf__free(btf); + return ERR_PTR(err); + } + + return btf; +} + +struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext) +{ + Elf_Data *btf_data = NULL, *btf_ext_data = NULL; + int err = 0, fd = -1, idx = 0; + struct btf *btf = NULL; + Elf_Scn *scn = NULL; + Elf *elf = NULL; + GElf_Ehdr ehdr; + + if (elf_version(EV_CURRENT) == EV_NONE) { + pr_warn("failed to init libelf for %s\n", path); + return ERR_PTR(-LIBBPF_ERRNO__LIBELF); + } + + fd = open(path, O_RDONLY); + if (fd < 0) { + err = -errno; + pr_warn("failed to open %s: %s\n", path, strerror(errno)); + return ERR_PTR(err); + } + + err = -LIBBPF_ERRNO__FORMAT; + + elf = elf_begin(fd, ELF_C_READ, NULL); + if (!elf) { + pr_warn("failed to open %s as ELF file\n", path); + goto done; + } + if (!gelf_getehdr(elf, &ehdr)) { + pr_warn("failed to get EHDR from %s\n", path); + goto done; + } + if (!elf_rawdata(elf_getscn(elf, ehdr.e_shstrndx), NULL)) { + pr_warn("failed to get e_shstrndx from %s\n", path); + goto done; + } + + while ((scn = elf_nextscn(elf, scn)) != NULL) { + GElf_Shdr sh; + char *name; + + idx++; + if (gelf_getshdr(scn, &sh) != &sh) { + pr_warn("failed to get section(%d) header from %s\n", + idx, path); + goto done; + } + name = elf_strptr(elf, ehdr.e_shstrndx, sh.sh_name); + if (!name) { + pr_warn("failed to get section(%d) name from %s\n", + idx, path); + goto done; + } + if (strcmp(name, BTF_ELF_SEC) == 0) { + btf_data = elf_getdata(scn, 0); + if (!btf_data) { + pr_warn("failed to get section(%d, %s) data from %s\n", + idx, name, path); + goto done; + } + continue; + } else if (btf_ext && strcmp(name, BTF_EXT_ELF_SEC) == 0) { + btf_ext_data = elf_getdata(scn, 0); + if (!btf_ext_data) { + pr_warn("failed to get section(%d, %s) data from %s\n", + idx, name, path); + goto done; + } + continue; + } + } + + err = 0; + + if (!btf_data) { + err = -ENOENT; + goto done; + } + btf = btf__new(btf_data->d_buf, btf_data->d_size); + if (IS_ERR(btf)) + goto done; + + switch (gelf_getclass(elf)) { + case ELFCLASS32: + btf__set_pointer_size(btf, 4); + break; + case ELFCLASS64: + btf__set_pointer_size(btf, 8); + break; + default: + pr_warn("failed to get ELF class (bitness) for %s\n", path); + break; + } + + if (btf_ext && btf_ext_data) { + *btf_ext = btf_ext__new(btf_ext_data->d_buf, + btf_ext_data->d_size); + if (IS_ERR(*btf_ext)) + goto done; + } else if (btf_ext) { + *btf_ext = NULL; + } +done: + if (elf) + elf_end(elf); + close(fd); + + if (err) + return ERR_PTR(err); + /* + * btf is always parsed before btf_ext, so no need to clean up + * btf_ext, if btf loading failed + */ + if (IS_ERR(btf)) + return btf; + if (btf_ext && IS_ERR(*btf_ext)) { + btf__free(btf); + err = PTR_ERR(*btf_ext); + return ERR_PTR(err); + } + return btf; +} + +struct btf *btf__parse_raw(const char *path) +{ + struct btf *btf = NULL; + void *data = NULL; + FILE *f = NULL; + __u16 magic; + int err = 0; + long sz; + + f = fopen(path, "rb"); + if (!f) { + err = -errno; + goto err_out; + } + + /* check BTF magic */ + if (fread(&magic, 1, sizeof(magic), f) < sizeof(magic)) { + err = -EIO; + goto err_out; + } + if (magic != BTF_MAGIC && magic != bswap_16(BTF_MAGIC)) { + /* definitely not a raw BTF */ + err = -EPROTO; + goto err_out; + } + + /* get file size */ + if (fseek(f, 0, SEEK_END)) { + err = -errno; + goto err_out; + } + sz = ftell(f); + if (sz < 0) { + err = -errno; + goto err_out; + } + /* rewind to the start */ + if (fseek(f, 0, SEEK_SET)) { + err = -errno; + goto err_out; + } + + /* pre-alloc memory and read all of BTF data */ + data = malloc(sz); + if (!data) { + err = -ENOMEM; + goto err_out; + } + if (fread(data, 1, sz, f) < sz) { + err = -EIO; + goto err_out; + } + + /* finally parse BTF data */ + btf = btf__new(data, sz); + +err_out: + free(data); + if (f) + fclose(f); + return err ? ERR_PTR(err) : btf; +} + +struct btf *btf__parse(const char *path, struct btf_ext **btf_ext) +{ + struct btf *btf; + + if (btf_ext) + *btf_ext = NULL; + + btf = btf__parse_raw(path); + if (!IS_ERR(btf) || PTR_ERR(btf) != -EPROTO) + return btf; + + return btf__parse_elf(path, btf_ext); +} + +static int compare_vsi_off(const void *_a, const void *_b) +{ + const struct btf_var_secinfo *a = _a; + const struct btf_var_secinfo *b = _b; + + return a->offset - b->offset; +} + +static int btf_fixup_datasec(struct bpf_object *obj, struct btf *btf, + struct btf_type *t) +{ + __u32 size = 0, off = 0, i, vars = btf_vlen(t); + const char *name = btf__name_by_offset(btf, t->name_off); + const struct btf_type *t_var; + struct btf_var_secinfo *vsi; + const struct btf_var *var; + int ret; + + if (!name) { + pr_debug("No name found in string section for DATASEC kind.\n"); + return -ENOENT; + } + + /* .extern datasec size and var offsets were set correctly during + * extern collection step, so just skip straight to sorting variables + */ + if (t->size) + goto sort_vars; + + ret = bpf_object__section_size(obj, name, &size); + if (ret || !size || (t->size && t->size != size)) { + pr_debug("Invalid size for section %s: %u bytes\n", name, size); + return -ENOENT; + } + + t->size = size; + + for (i = 0, vsi = btf_var_secinfos(t); i < vars; i++, vsi++) { + t_var = btf__type_by_id(btf, vsi->type); + var = btf_var(t_var); + + if (!btf_is_var(t_var)) { + pr_debug("Non-VAR type seen in section %s\n", name); + return -EINVAL; + } + + if (var->linkage == BTF_VAR_STATIC) + continue; + + name = btf__name_by_offset(btf, t_var->name_off); + if (!name) { + pr_debug("No name found in string section for VAR kind\n"); + return -ENOENT; + } + + ret = bpf_object__variable_offset(obj, name, &off); + if (ret) { + pr_debug("No offset found in symbol table for VAR %s\n", + name); + return -ENOENT; + } + + vsi->offset = off; + } + +sort_vars: + qsort(btf_var_secinfos(t), vars, sizeof(*vsi), compare_vsi_off); + return 0; +} + +int btf__finalize_data(struct bpf_object *obj, struct btf *btf) +{ + int err = 0; + __u32 i; + + for (i = 1; i <= btf->nr_types; i++) { + struct btf_type *t = btf_type_by_id(btf, i); + + /* Loader needs to fix up some of the things compiler + * couldn't get its hands on while emitting BTF. This + * is section size and global variable offset. We use + * the info from the ELF itself for this purpose. + */ + if (btf_is_datasec(t)) { + err = btf_fixup_datasec(obj, btf, t); + if (err) + break; + } + } + + return err; +} + +static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian); + +int btf__load(struct btf *btf) +{ + __u32 log_buf_size = 0, raw_size; + char *log_buf = NULL; + void *raw_data; + int err = 0; + + if (btf->fd >= 0) + return -EEXIST; + +retry_load: + if (log_buf_size) { + log_buf = malloc(log_buf_size); + if (!log_buf) + return -ENOMEM; + + *log_buf = 0; + } + + raw_data = btf_get_raw_data(btf, &raw_size, false); + if (!raw_data) { + err = -ENOMEM; + goto done; + } + /* cache native raw data representation */ + btf->raw_size = raw_size; + btf->raw_data = raw_data; + + btf->fd = bpf_load_btf(raw_data, raw_size, log_buf, log_buf_size, false); + if (btf->fd < 0) { + if (!log_buf || errno == ENOSPC) { + log_buf_size = max((__u32)BPF_LOG_BUF_SIZE, + log_buf_size << 1); + free(log_buf); + goto retry_load; + } + + err = -errno; + pr_warn("Error loading BTF: %s(%d)\n", strerror(errno), errno); + if (*log_buf) + pr_warn("%s\n", log_buf); + goto done; + } + +done: + free(log_buf); + return err; +} + +int btf__fd(const struct btf *btf) +{ + return btf->fd; +} + +void btf__set_fd(struct btf *btf, int fd) +{ + btf->fd = fd; +} + +static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian) +{ + struct btf_header *hdr = btf->hdr; + struct btf_type *t; + void *data, *p; + __u32 data_sz; + int i; + + data = swap_endian ? btf->raw_data_swapped : btf->raw_data; + if (data) { + *size = btf->raw_size; + return data; + } + + data_sz = hdr->hdr_len + hdr->type_len + hdr->str_len; + data = calloc(1, data_sz); + if (!data) + return NULL; + p = data; + + memcpy(p, hdr, hdr->hdr_len); + if (swap_endian) + btf_bswap_hdr(p); + p += hdr->hdr_len; + + memcpy(p, btf->types_data, hdr->type_len); + if (swap_endian) { + for (i = 1; i <= btf->nr_types; i++) { + t = p + btf->type_offs[i]; + /* btf_bswap_type_rest() relies on native t->info, so + * we swap base type info after we swapped all the + * additional information + */ + if (btf_bswap_type_rest(t)) + goto err_out; + btf_bswap_type_base(t); + } + } + p += hdr->type_len; + + memcpy(p, btf->strs_data, hdr->str_len); + p += hdr->str_len; + + *size = data_sz; + return data; +err_out: + free(data); + return NULL; +} + +const void *btf__get_raw_data(const struct btf *btf_ro, __u32 *size) +{ + struct btf *btf = (struct btf *)btf_ro; + __u32 data_sz; + void *data; + + data = btf_get_raw_data(btf, &data_sz, btf->swapped_endian); + if (!data) + return NULL; + + btf->raw_size = data_sz; + if (btf->swapped_endian) + btf->raw_data_swapped = data; + else + btf->raw_data = data; + *size = data_sz; + return data; +} + +const char *btf__str_by_offset(const struct btf *btf, __u32 offset) +{ + if (offset < btf->hdr->str_len) + return btf->strs_data + offset; + else + return NULL; +} + +const char *btf__name_by_offset(const struct btf *btf, __u32 offset) +{ + return btf__str_by_offset(btf, offset); +} + +int btf__get_from_id(__u32 id, struct btf **btf) +{ + struct bpf_btf_info btf_info = { 0 }; + __u32 len = sizeof(btf_info); + __u32 last_size; + int btf_fd; + void *ptr; + int err; + + err = 0; + *btf = NULL; + btf_fd = bpf_btf_get_fd_by_id(id); + if (btf_fd < 0) + return 0; + + /* we won't know btf_size until we call bpf_obj_get_info_by_fd(). so + * let's start with a sane default - 4KiB here - and resize it only if + * bpf_obj_get_info_by_fd() needs a bigger buffer. + */ + btf_info.btf_size = 4096; + last_size = btf_info.btf_size; + ptr = malloc(last_size); + if (!ptr) { + err = -ENOMEM; + goto exit_free; + } + + memset(ptr, 0, last_size); + btf_info.btf = ptr_to_u64(ptr); + err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len); + + if (!err && btf_info.btf_size > last_size) { + void *temp_ptr; + + last_size = btf_info.btf_size; + temp_ptr = realloc(ptr, last_size); + if (!temp_ptr) { + err = -ENOMEM; + goto exit_free; + } + ptr = temp_ptr; + memset(ptr, 0, last_size); + btf_info.btf = ptr_to_u64(ptr); + err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len); + } + + if (err || btf_info.btf_size > last_size) { + err = errno; + goto exit_free; + } + + *btf = btf__new((__u8 *)(long)btf_info.btf, btf_info.btf_size); + if (IS_ERR(*btf)) { + err = PTR_ERR(*btf); + *btf = NULL; + } + +exit_free: + close(btf_fd); + free(ptr); + + return err; +} + +int btf__get_map_kv_tids(const struct btf *btf, const char *map_name, + __u32 expected_key_size, __u32 expected_value_size, + __u32 *key_type_id, __u32 *value_type_id) +{ + const struct btf_type *container_type; + const struct btf_member *key, *value; + const size_t max_name = 256; + char container_name[max_name]; + __s64 key_size, value_size; + __s32 container_id; + + if (snprintf(container_name, max_name, "____btf_map_%s", map_name) == + max_name) { + pr_warn("map:%s length of '____btf_map_%s' is too long\n", + map_name, map_name); + return -EINVAL; + } + + container_id = btf__find_by_name(btf, container_name); + if (container_id < 0) { + pr_debug("map:%s container_name:%s cannot be found in BTF. Missing BPF_ANNOTATE_KV_PAIR?\n", + map_name, container_name); + return container_id; + } + + container_type = btf__type_by_id(btf, container_id); + if (!container_type) { + pr_warn("map:%s cannot find BTF type for container_id:%u\n", + map_name, container_id); + return -EINVAL; + } + + if (!btf_is_struct(container_type) || btf_vlen(container_type) < 2) { + pr_warn("map:%s container_name:%s is an invalid container struct\n", + map_name, container_name); + return -EINVAL; + } + + key = btf_members(container_type); + value = key + 1; + + key_size = btf__resolve_size(btf, key->type); + if (key_size < 0) { + pr_warn("map:%s invalid BTF key_type_size\n", map_name); + return key_size; + } + + if (expected_key_size != key_size) { + pr_warn("map:%s btf_key_type_size:%u != map_def_key_size:%u\n", + map_name, (__u32)key_size, expected_key_size); + return -EINVAL; + } + + value_size = btf__resolve_size(btf, value->type); + if (value_size < 0) { + pr_warn("map:%s invalid BTF value_type_size\n", map_name); + return value_size; + } + + if (expected_value_size != value_size) { + pr_warn("map:%s btf_value_type_size:%u != map_def_value_size:%u\n", + map_name, (__u32)value_size, expected_value_size); + return -EINVAL; + } + + *key_type_id = key->type; + *value_type_id = value->type; + + return 0; +} + +static size_t strs_hash_fn(const void *key, void *ctx) +{ + struct btf *btf = ctx; + const char *str = btf->strs_data + (long)key; + + return str_hash(str); +} + +static bool strs_hash_equal_fn(const void *key1, const void *key2, void *ctx) +{ + struct btf *btf = ctx; + const char *str1 = btf->strs_data + (long)key1; + const char *str2 = btf->strs_data + (long)key2; + + return strcmp(str1, str2) == 0; +} + +static void btf_invalidate_raw_data(struct btf *btf) +{ + if (btf->raw_data) { + free(btf->raw_data); + btf->raw_data = NULL; + } + if (btf->raw_data_swapped) { + free(btf->raw_data_swapped); + btf->raw_data_swapped = NULL; + } +} + +/* Ensure BTF is ready to be modified (by splitting into a three memory + * regions for header, types, and strings). Also invalidate cached + * raw_data, if any. + */ +static int btf_ensure_modifiable(struct btf *btf) +{ + void *hdr, *types, *strs, *strs_end, *s; + struct hashmap *hash = NULL; + long off; + int err; + + if (btf_is_modifiable(btf)) { + /* any BTF modification invalidates raw_data */ + btf_invalidate_raw_data(btf); + return 0; + } + + /* split raw data into three memory regions */ + hdr = malloc(btf->hdr->hdr_len); + types = malloc(btf->hdr->type_len); + strs = malloc(btf->hdr->str_len); + if (!hdr || !types || !strs) + goto err_out; + + memcpy(hdr, btf->hdr, btf->hdr->hdr_len); + memcpy(types, btf->types_data, btf->hdr->type_len); + memcpy(strs, btf->strs_data, btf->hdr->str_len); + + /* build lookup index for all strings */ + hash = hashmap__new(strs_hash_fn, strs_hash_equal_fn, btf); + if (IS_ERR(hash)) { + err = PTR_ERR(hash); + hash = NULL; + goto err_out; + } + + strs_end = strs + btf->hdr->str_len; + for (off = 0, s = strs; s < strs_end; off += strlen(s) + 1, s = strs + off) { + /* hashmap__add() returns EEXIST if string with the same + * content already is in the hash map + */ + err = hashmap__add(hash, (void *)off, (void *)off); + if (err == -EEXIST) + continue; /* duplicate */ + if (err) + goto err_out; + } + + /* only when everything was successful, update internal state */ + btf->hdr = hdr; + btf->types_data = types; + btf->types_data_cap = btf->hdr->type_len; + btf->strs_data = strs; + btf->strs_data_cap = btf->hdr->str_len; + btf->strs_hash = hash; + /* if BTF was created from scratch, all strings are guaranteed to be + * unique and deduplicated + */ + btf->strs_deduped = btf->hdr->str_len <= 1; + + /* invalidate raw_data representation */ + btf_invalidate_raw_data(btf); + + return 0; + +err_out: + hashmap__free(hash); + free(hdr); + free(types); + free(strs); + return -ENOMEM; +} + +static void *btf_add_str_mem(struct btf *btf, size_t add_sz) +{ + return btf_add_mem(&btf->strs_data, &btf->strs_data_cap, 1, + btf->hdr->str_len, BTF_MAX_STR_OFFSET, add_sz); +} + +/* Find an offset in BTF string section that corresponds to a given string *s*. + * Returns: + * - >0 offset into string section, if string is found; + * - -ENOENT, if string is not in the string section; + * - <0, on any other error. + */ +int btf__find_str(struct btf *btf, const char *s) +{ + long old_off, new_off, len; + void *p; + + /* BTF needs to be in a modifiable state to build string lookup index */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + /* see btf__add_str() for why we do this */ + len = strlen(s) + 1; + p = btf_add_str_mem(btf, len); + if (!p) + return -ENOMEM; + + new_off = btf->hdr->str_len; + memcpy(p, s, len); + + if (hashmap__find(btf->strs_hash, (void *)new_off, (void **)&old_off)) + return old_off; + + return -ENOENT; +} + +/* Add a string s to the BTF string section. + * Returns: + * - > 0 offset into string section, on success; + * - < 0, on error. + */ +int btf__add_str(struct btf *btf, const char *s) +{ + long old_off, new_off, len; + void *p; + int err; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + /* Hashmap keys are always offsets within btf->strs_data, so to even + * look up some string from the "outside", we need to first append it + * at the end, so that it can be addressed with an offset. Luckily, + * until btf->hdr->str_len is incremented, that string is just a piece + * of garbage for the rest of BTF code, so no harm, no foul. On the + * other hand, if the string is unique, it's already appended and + * ready to be used, only a simple btf->hdr->str_len increment away. + */ + len = strlen(s) + 1; + p = btf_add_str_mem(btf, len); + if (!p) + return -ENOMEM; + + new_off = btf->hdr->str_len; + memcpy(p, s, len); + + /* Now attempt to add the string, but only if the string with the same + * contents doesn't exist already (HASHMAP_ADD strategy). If such + * string exists, we'll get its offset in old_off (that's old_key). + */ + err = hashmap__insert(btf->strs_hash, (void *)new_off, (void *)new_off, + HASHMAP_ADD, (const void **)&old_off, NULL); + if (err == -EEXIST) + return old_off; /* duplicated string, return existing offset */ + if (err) + return err; + + btf->hdr->str_len += len; /* new unique string, adjust data length */ + return new_off; +} + +static void *btf_add_type_mem(struct btf *btf, size_t add_sz) +{ + return btf_add_mem(&btf->types_data, &btf->types_data_cap, 1, + btf->hdr->type_len, UINT_MAX, add_sz); +} + +static __u32 btf_type_info(int kind, int vlen, int kflag) +{ + return (kflag << 31) | (kind << 24) | vlen; +} + +static void btf_type_inc_vlen(struct btf_type *t) +{ + t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, btf_kflag(t)); +} + +/* + * Append new BTF_KIND_INT type with: + * - *name* - non-empty, non-NULL type name; + * - *sz* - power-of-2 (1, 2, 4, ..) size of the type, in bytes; + * - encoding is a combination of BTF_INT_SIGNED, BTF_INT_CHAR, BTF_INT_BOOL. + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding) +{ + struct btf_type *t; + int sz, err, name_off; + + /* non-empty name */ + if (!name || !name[0]) + return -EINVAL; + /* byte_sz must be power of 2 */ + if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 16) + return -EINVAL; + if (encoding & ~(BTF_INT_SIGNED | BTF_INT_CHAR | BTF_INT_BOOL)) + return -EINVAL; + + /* deconstruct BTF, if necessary, and invalidate raw_data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type) + sizeof(int); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + /* if something goes wrong later, we might end up with an extra string, + * but that shouldn't be a problem, because BTF can't be constructed + * completely anyway and will most probably be just discarded + */ + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + t->name_off = name_off; + t->info = btf_type_info(BTF_KIND_INT, 0, 0); + t->size = byte_sz; + /* set INT info, we don't allow setting legacy bit offset/size */ + *(__u32 *)(t + 1) = (encoding << 24) | (byte_sz * 8); + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* it's completely legal to append BTF types with type IDs pointing forward to + * types that haven't been appended yet, so we only make sure that id looks + * sane, we can't guarantee that ID will always be valid + */ +static int validate_type_id(int id) +{ + if (id < 0 || id > BTF_MAX_NR_TYPES) + return -EINVAL; + return 0; +} + +/* generic append function for PTR, TYPEDEF, CONST/VOLATILE/RESTRICT */ +static int btf_add_ref_kind(struct btf *btf, int kind, const char *name, int ref_type_id) +{ + struct btf_type *t; + int sz, name_off = 0, err; + + if (validate_type_id(ref_type_id)) + return -EINVAL; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + } + + t->name_off = name_off; + t->info = btf_type_info(kind, 0, 0); + t->type = ref_type_id; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new BTF_KIND_PTR type with: + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_ptr(struct btf *btf, int ref_type_id) +{ + return btf_add_ref_kind(btf, BTF_KIND_PTR, NULL, ref_type_id); +} + +/* + * Append new BTF_KIND_ARRAY type with: + * - *index_type_id* - type ID of the type describing array index; + * - *elem_type_id* - type ID of the type describing array element; + * - *nr_elems* - the size of the array; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_array(struct btf *btf, int index_type_id, int elem_type_id, __u32 nr_elems) +{ + struct btf_type *t; + struct btf_array *a; + int sz, err; + + if (validate_type_id(index_type_id) || validate_type_id(elem_type_id)) + return -EINVAL; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type) + sizeof(struct btf_array); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + t->name_off = 0; + t->info = btf_type_info(BTF_KIND_ARRAY, 0, 0); + t->size = 0; + + a = btf_array(t); + a->type = elem_type_id; + a->index_type = index_type_id; + a->nelems = nr_elems; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* generic STRUCT/UNION append function */ +static int btf_add_composite(struct btf *btf, int kind, const char *name, __u32 bytes_sz) +{ + struct btf_type *t; + int sz, err, name_off = 0; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + } + + /* start out with vlen=0 and no kflag; this will be adjusted when + * adding each member + */ + t->name_off = name_off; + t->info = btf_type_info(kind, 0, 0); + t->size = bytes_sz; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new BTF_KIND_STRUCT type with: + * - *name* - name of the struct, can be NULL or empty for anonymous structs; + * - *byte_sz* - size of the struct, in bytes; + * + * Struct initially has no fields in it. Fields can be added by + * btf__add_field() right after btf__add_struct() succeeds. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_struct(struct btf *btf, const char *name, __u32 byte_sz) +{ + return btf_add_composite(btf, BTF_KIND_STRUCT, name, byte_sz); +} + +/* + * Append new BTF_KIND_UNION type with: + * - *name* - name of the union, can be NULL or empty for anonymous union; + * - *byte_sz* - size of the union, in bytes; + * + * Union initially has no fields in it. Fields can be added by + * btf__add_field() right after btf__add_union() succeeds. All fields + * should have *bit_offset* of 0. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_union(struct btf *btf, const char *name, __u32 byte_sz) +{ + return btf_add_composite(btf, BTF_KIND_UNION, name, byte_sz); +} + +/* + * Append new field for the current STRUCT/UNION type with: + * - *name* - name of the field, can be NULL or empty for anonymous field; + * - *type_id* - type ID for the type describing field type; + * - *bit_offset* - bit offset of the start of the field within struct/union; + * - *bit_size* - bit size of a bitfield, 0 for non-bitfield fields; + * Returns: + * - 0, on success; + * - <0, on error. + */ +int btf__add_field(struct btf *btf, const char *name, int type_id, + __u32 bit_offset, __u32 bit_size) +{ + struct btf_type *t; + struct btf_member *m; + bool is_bitfield; + int sz, name_off = 0; + + /* last type should be union/struct */ + if (btf->nr_types == 0) + return -EINVAL; + t = btf_type_by_id(btf, btf->nr_types); + if (!btf_is_composite(t)) + return -EINVAL; + + if (validate_type_id(type_id)) + return -EINVAL; + /* best-effort bit field offset/size enforcement */ + is_bitfield = bit_size || (bit_offset % 8 != 0); + if (is_bitfield && (bit_size == 0 || bit_size > 255 || bit_offset > 0xffffff)) + return -EINVAL; + + /* only offset 0 is allowed for unions */ + if (btf_is_union(t) && bit_offset) + return -EINVAL; + + /* decompose and invalidate raw data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_member); + m = btf_add_type_mem(btf, sz); + if (!m) + return -ENOMEM; + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + } + + m->name_off = name_off; + m->type = type_id; + m->offset = bit_offset | (bit_size << 24); + + /* btf_add_type_mem can invalidate t pointer */ + t = btf_type_by_id(btf, btf->nr_types); + /* update parent type's vlen and kflag */ + t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, is_bitfield || btf_kflag(t)); + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + return 0; +} + +/* + * Append new BTF_KIND_ENUM type with: + * - *name* - name of the enum, can be NULL or empty for anonymous enums; + * - *byte_sz* - size of the enum, in bytes. + * + * Enum initially has no enum values in it (and corresponds to enum forward + * declaration). Enumerator values can be added by btf__add_enum_value() + * immediately after btf__add_enum() succeeds. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_enum(struct btf *btf, const char *name, __u32 byte_sz) +{ + struct btf_type *t; + int sz, err, name_off = 0; + + /* byte_sz must be power of 2 */ + if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 8) + return -EINVAL; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + } + + /* start out with vlen=0; it will be adjusted when adding enum values */ + t->name_off = name_off; + t->info = btf_type_info(BTF_KIND_ENUM, 0, 0); + t->size = byte_sz; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new enum value for the current ENUM type with: + * - *name* - name of the enumerator value, can't be NULL or empty; + * - *value* - integer value corresponding to enum value *name*; + * Returns: + * - 0, on success; + * - <0, on error. + */ +int btf__add_enum_value(struct btf *btf, const char *name, __s64 value) +{ + struct btf_type *t; + struct btf_enum *v; + int sz, name_off; + + /* last type should be BTF_KIND_ENUM */ + if (btf->nr_types == 0) + return -EINVAL; + t = btf_type_by_id(btf, btf->nr_types); + if (!btf_is_enum(t)) + return -EINVAL; + + /* non-empty name */ + if (!name || !name[0]) + return -EINVAL; + if (value < INT_MIN || value > UINT_MAX) + return -E2BIG; + + /* decompose and invalidate raw data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_enum); + v = btf_add_type_mem(btf, sz); + if (!v) + return -ENOMEM; + + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + v->name_off = name_off; + v->val = value; + + /* update parent type's vlen */ + t = btf_type_by_id(btf, btf->nr_types); + btf_type_inc_vlen(t); + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + return 0; +} + +/* + * Append new BTF_KIND_FWD type with: + * - *name*, non-empty/non-NULL name; + * - *fwd_kind*, kind of forward declaration, one of BTF_FWD_STRUCT, + * BTF_FWD_UNION, or BTF_FWD_ENUM; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind) +{ + if (!name || !name[0]) + return -EINVAL; + + switch (fwd_kind) { + case BTF_FWD_STRUCT: + case BTF_FWD_UNION: { + struct btf_type *t; + int id; + + id = btf_add_ref_kind(btf, BTF_KIND_FWD, name, 0); + if (id <= 0) + return id; + t = btf_type_by_id(btf, id); + t->info = btf_type_info(BTF_KIND_FWD, 0, fwd_kind == BTF_FWD_UNION); + return id; + } + case BTF_FWD_ENUM: + /* enum forward in BTF currently is just an enum with no enum + * values; we also assume a standard 4-byte size for it + */ + return btf__add_enum(btf, name, sizeof(int)); + default: + return -EINVAL; + } +} + +/* + * Append new BTF_KING_TYPEDEF type with: + * - *name*, non-empty/non-NULL name; + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id) +{ + if (!name || !name[0]) + return -EINVAL; + + return btf_add_ref_kind(btf, BTF_KIND_TYPEDEF, name, ref_type_id); +} + +/* + * Append new BTF_KIND_VOLATILE type with: + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_volatile(struct btf *btf, int ref_type_id) +{ + return btf_add_ref_kind(btf, BTF_KIND_VOLATILE, NULL, ref_type_id); +} + +/* + * Append new BTF_KIND_CONST type with: + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_const(struct btf *btf, int ref_type_id) +{ + return btf_add_ref_kind(btf, BTF_KIND_CONST, NULL, ref_type_id); +} + +/* + * Append new BTF_KIND_RESTRICT type with: + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_restrict(struct btf *btf, int ref_type_id) +{ + return btf_add_ref_kind(btf, BTF_KIND_RESTRICT, NULL, ref_type_id); +} + +/* + * Append new BTF_KIND_FUNC type with: + * - *name*, non-empty/non-NULL name; + * - *proto_type_id* - FUNC_PROTO's type ID, it might not exist yet; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_func(struct btf *btf, const char *name, + enum btf_func_linkage linkage, int proto_type_id) +{ + int id; + + if (!name || !name[0]) + return -EINVAL; + if (linkage != BTF_FUNC_STATIC && linkage != BTF_FUNC_GLOBAL && + linkage != BTF_FUNC_EXTERN) + return -EINVAL; + + id = btf_add_ref_kind(btf, BTF_KIND_FUNC, name, proto_type_id); + if (id > 0) { + struct btf_type *t = btf_type_by_id(btf, id); + + t->info = btf_type_info(BTF_KIND_FUNC, linkage, 0); + } + return id; +} + +/* + * Append new BTF_KIND_FUNC_PROTO with: + * - *ret_type_id* - type ID for return result of a function. + * + * Function prototype initially has no arguments, but they can be added by + * btf__add_func_param() one by one, immediately after + * btf__add_func_proto() succeeded. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_func_proto(struct btf *btf, int ret_type_id) +{ + struct btf_type *t; + int sz, err; + + if (validate_type_id(ret_type_id)) + return -EINVAL; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + /* start out with vlen=0; this will be adjusted when adding enum + * values, if necessary + */ + t->name_off = 0; + t->info = btf_type_info(BTF_KIND_FUNC_PROTO, 0, 0); + t->type = ret_type_id; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new function parameter for current FUNC_PROTO type with: + * - *name* - parameter name, can be NULL or empty; + * - *type_id* - type ID describing the type of the parameter. + * Returns: + * - 0, on success; + * - <0, on error. + */ +int btf__add_func_param(struct btf *btf, const char *name, int type_id) +{ + struct btf_type *t; + struct btf_param *p; + int sz, name_off = 0; + + if (validate_type_id(type_id)) + return -EINVAL; + + /* last type should be BTF_KIND_FUNC_PROTO */ + if (btf->nr_types == 0) + return -EINVAL; + t = btf_type_by_id(btf, btf->nr_types); + if (!btf_is_func_proto(t)) + return -EINVAL; + + /* decompose and invalidate raw data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_param); + p = btf_add_type_mem(btf, sz); + if (!p) + return -ENOMEM; + + if (name && name[0]) { + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + } + + p->name_off = name_off; + p->type = type_id; + + /* update parent type's vlen */ + t = btf_type_by_id(btf, btf->nr_types); + btf_type_inc_vlen(t); + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + return 0; +} + +/* + * Append new BTF_KIND_VAR type with: + * - *name* - non-empty/non-NULL name; + * - *linkage* - variable linkage, one of BTF_VAR_STATIC, + * BTF_VAR_GLOBAL_ALLOCATED, or BTF_VAR_GLOBAL_EXTERN; + * - *type_id* - type ID of the type describing the type of the variable. + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id) +{ + struct btf_type *t; + struct btf_var *v; + int sz, err, name_off; + + /* non-empty name */ + if (!name || !name[0]) + return -EINVAL; + if (linkage != BTF_VAR_STATIC && linkage != BTF_VAR_GLOBAL_ALLOCATED && + linkage != BTF_VAR_GLOBAL_EXTERN) + return -EINVAL; + if (validate_type_id(type_id)) + return -EINVAL; + + /* deconstruct BTF, if necessary, and invalidate raw_data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type) + sizeof(struct btf_var); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + t->name_off = name_off; + t->info = btf_type_info(BTF_KIND_VAR, 0, 0); + t->type = type_id; + + v = btf_var(t); + v->linkage = linkage; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new BTF_KIND_DATASEC type with: + * - *name* - non-empty/non-NULL name; + * - *byte_sz* - data section size, in bytes. + * + * Data section is initially empty. Variables info can be added with + * btf__add_datasec_var_info() calls, after btf__add_datasec() succeeds. + * + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz) +{ + struct btf_type *t; + int sz, err, name_off; + + /* non-empty name */ + if (!name || !name[0]) + return -EINVAL; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + /* start with vlen=0, which will be update as var_secinfos are added */ + t->name_off = name_off; + t->info = btf_type_info(BTF_KIND_DATASEC, 0, 0); + t->size = byte_sz; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + btf->nr_types++; + return btf->nr_types; +} + +/* + * Append new data section variable information entry for current DATASEC type: + * - *var_type_id* - type ID, describing type of the variable; + * - *offset* - variable offset within data section, in bytes; + * - *byte_sz* - variable size, in bytes. + * + * Returns: + * - 0, on success; + * - <0, on error. + */ +int btf__add_datasec_var_info(struct btf *btf, int var_type_id, __u32 offset, __u32 byte_sz) +{ + struct btf_type *t; + struct btf_var_secinfo *v; + int sz; + + /* last type should be BTF_KIND_DATASEC */ + if (btf->nr_types == 0) + return -EINVAL; + t = btf_type_by_id(btf, btf->nr_types); + if (!btf_is_datasec(t)) + return -EINVAL; + + if (validate_type_id(var_type_id)) + return -EINVAL; + + /* decompose and invalidate raw data */ + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_var_secinfo); + v = btf_add_type_mem(btf, sz); + if (!v) + return -ENOMEM; + + v->type = var_type_id; + v->offset = offset; + v->size = byte_sz; + + /* update parent type's vlen */ + t = btf_type_by_id(btf, btf->nr_types); + btf_type_inc_vlen(t); + + btf->hdr->type_len += sz; + btf->hdr->str_off += sz; + return 0; +} + +struct btf_ext_sec_setup_param { + __u32 off; + __u32 len; + __u32 min_rec_size; + struct btf_ext_info *ext_info; + const char *desc; +}; + +static int btf_ext_setup_info(struct btf_ext *btf_ext, + struct btf_ext_sec_setup_param *ext_sec) +{ + const struct btf_ext_info_sec *sinfo; + struct btf_ext_info *ext_info; + __u32 info_left, record_size; + /* The start of the info sec (including the __u32 record_size). */ + void *info; + + if (ext_sec->len == 0) + return 0; + + if (ext_sec->off & 0x03) { + pr_debug(".BTF.ext %s section is not aligned to 4 bytes\n", + ext_sec->desc); + return -EINVAL; + } + + info = btf_ext->data + btf_ext->hdr->hdr_len + ext_sec->off; + info_left = ext_sec->len; + + if (btf_ext->data + btf_ext->data_size < info + ext_sec->len) { + pr_debug("%s section (off:%u len:%u) is beyond the end of the ELF section .BTF.ext\n", + ext_sec->desc, ext_sec->off, ext_sec->len); + return -EINVAL; + } + + /* At least a record size */ + if (info_left < sizeof(__u32)) { + pr_debug(".BTF.ext %s record size not found\n", ext_sec->desc); + return -EINVAL; + } + + /* The record size needs to meet the minimum standard */ + record_size = *(__u32 *)info; + if (record_size < ext_sec->min_rec_size || + record_size & 0x03) { + pr_debug("%s section in .BTF.ext has invalid record size %u\n", + ext_sec->desc, record_size); + return -EINVAL; + } + + sinfo = info + sizeof(__u32); + info_left -= sizeof(__u32); + + /* If no records, return failure now so .BTF.ext won't be used. */ + if (!info_left) { + pr_debug("%s section in .BTF.ext has no records", ext_sec->desc); + return -EINVAL; + } + + while (info_left) { + unsigned int sec_hdrlen = sizeof(struct btf_ext_info_sec); + __u64 total_record_size; + __u32 num_records; + + if (info_left < sec_hdrlen) { + pr_debug("%s section header is not found in .BTF.ext\n", + ext_sec->desc); + return -EINVAL; + } + + num_records = sinfo->num_info; + if (num_records == 0) { + pr_debug("%s section has incorrect num_records in .BTF.ext\n", + ext_sec->desc); + return -EINVAL; + } + + total_record_size = sec_hdrlen + + (__u64)num_records * record_size; + if (info_left < total_record_size) { + pr_debug("%s section has incorrect num_records in .BTF.ext\n", + ext_sec->desc); + return -EINVAL; + } + + info_left -= total_record_size; + sinfo = (void *)sinfo + total_record_size; + } + + ext_info = ext_sec->ext_info; + ext_info->len = ext_sec->len - sizeof(__u32); + ext_info->rec_size = record_size; + ext_info->info = info + sizeof(__u32); + + return 0; +} + +static int btf_ext_setup_func_info(struct btf_ext *btf_ext) +{ + struct btf_ext_sec_setup_param param = { + .off = btf_ext->hdr->func_info_off, + .len = btf_ext->hdr->func_info_len, + .min_rec_size = sizeof(struct bpf_func_info_min), + .ext_info = &btf_ext->func_info, + .desc = "func_info" + }; + + return btf_ext_setup_info(btf_ext, ¶m); +} + +static int btf_ext_setup_line_info(struct btf_ext *btf_ext) +{ + struct btf_ext_sec_setup_param param = { + .off = btf_ext->hdr->line_info_off, + .len = btf_ext->hdr->line_info_len, + .min_rec_size = sizeof(struct bpf_line_info_min), + .ext_info = &btf_ext->line_info, + .desc = "line_info", + }; + + return btf_ext_setup_info(btf_ext, ¶m); +} + +static int btf_ext_setup_core_relos(struct btf_ext *btf_ext) +{ + struct btf_ext_sec_setup_param param = { + .off = btf_ext->hdr->core_relo_off, + .len = btf_ext->hdr->core_relo_len, + .min_rec_size = sizeof(struct bpf_core_relo), + .ext_info = &btf_ext->core_relo_info, + .desc = "core_relo", + }; + + return btf_ext_setup_info(btf_ext, ¶m); +} + +static int btf_ext_parse_hdr(__u8 *data, __u32 data_size) +{ + const struct btf_ext_header *hdr = (struct btf_ext_header *)data; + + if (data_size < offsetofend(struct btf_ext_header, hdr_len) || + data_size < hdr->hdr_len) { + pr_debug("BTF.ext header not found"); + return -EINVAL; + } + + if (hdr->magic == bswap_16(BTF_MAGIC)) { + pr_warn("BTF.ext in non-native endianness is not supported\n"); + return -ENOTSUP; + } else if (hdr->magic != BTF_MAGIC) { + pr_debug("Invalid BTF.ext magic:%x\n", hdr->magic); + return -EINVAL; + } + + if (hdr->version != BTF_VERSION) { + pr_debug("Unsupported BTF.ext version:%u\n", hdr->version); + return -ENOTSUP; + } + + if (hdr->flags) { + pr_debug("Unsupported BTF.ext flags:%x\n", hdr->flags); + return -ENOTSUP; + } + + if (data_size == hdr->hdr_len) { + pr_debug("BTF.ext has no data\n"); + return -EINVAL; + } + + return 0; +} + +void btf_ext__free(struct btf_ext *btf_ext) +{ + if (IS_ERR_OR_NULL(btf_ext)) + return; + free(btf_ext->data); + free(btf_ext); +} + +struct btf_ext *btf_ext__new(__u8 *data, __u32 size) +{ + struct btf_ext *btf_ext; + int err; + + err = btf_ext_parse_hdr(data, size); + if (err) + return ERR_PTR(err); + + btf_ext = calloc(1, sizeof(struct btf_ext)); + if (!btf_ext) + return ERR_PTR(-ENOMEM); + + btf_ext->data_size = size; + btf_ext->data = malloc(size); + if (!btf_ext->data) { + err = -ENOMEM; + goto done; + } + memcpy(btf_ext->data, data, size); + + if (btf_ext->hdr->hdr_len < + offsetofend(struct btf_ext_header, line_info_len)) + goto done; + err = btf_ext_setup_func_info(btf_ext); + if (err) + goto done; + + err = btf_ext_setup_line_info(btf_ext); + if (err) + goto done; + + if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, core_relo_len)) + goto done; + err = btf_ext_setup_core_relos(btf_ext); + if (err) + goto done; + +done: + if (err) { + btf_ext__free(btf_ext); + return ERR_PTR(err); + } + + return btf_ext; +} + +const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, __u32 *size) +{ + *size = btf_ext->data_size; + return btf_ext->data; +} + +static int btf_ext_reloc_info(const struct btf *btf, + const struct btf_ext_info *ext_info, + const char *sec_name, __u32 insns_cnt, + void **info, __u32 *cnt) +{ + __u32 sec_hdrlen = sizeof(struct btf_ext_info_sec); + __u32 i, record_size, existing_len, records_len; + struct btf_ext_info_sec *sinfo; + const char *info_sec_name; + __u64 remain_len; + void *data; + + record_size = ext_info->rec_size; + sinfo = ext_info->info; + remain_len = ext_info->len; + while (remain_len > 0) { + records_len = sinfo->num_info * record_size; + info_sec_name = btf__name_by_offset(btf, sinfo->sec_name_off); + if (strcmp(info_sec_name, sec_name)) { + remain_len -= sec_hdrlen + records_len; + sinfo = (void *)sinfo + sec_hdrlen + records_len; + continue; + } + + existing_len = (*cnt) * record_size; + data = realloc(*info, existing_len + records_len); + if (!data) + return -ENOMEM; + + memcpy(data + existing_len, sinfo->data, records_len); + /* adjust insn_off only, the rest data will be passed + * to the kernel. + */ + for (i = 0; i < sinfo->num_info; i++) { + __u32 *insn_off; + + insn_off = data + existing_len + (i * record_size); + *insn_off = *insn_off / sizeof(struct bpf_insn) + + insns_cnt; + } + *info = data; + *cnt += sinfo->num_info; + return 0; + } + + return -ENOENT; +} + +int btf_ext__reloc_func_info(const struct btf *btf, + const struct btf_ext *btf_ext, + const char *sec_name, __u32 insns_cnt, + void **func_info, __u32 *cnt) +{ + return btf_ext_reloc_info(btf, &btf_ext->func_info, sec_name, + insns_cnt, func_info, cnt); +} + +int btf_ext__reloc_line_info(const struct btf *btf, + const struct btf_ext *btf_ext, + const char *sec_name, __u32 insns_cnt, + void **line_info, __u32 *cnt) +{ + return btf_ext_reloc_info(btf, &btf_ext->line_info, sec_name, + insns_cnt, line_info, cnt); +} + +__u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext) +{ + return btf_ext->func_info.rec_size; +} + +__u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext) +{ + return btf_ext->line_info.rec_size; +} + +struct btf_dedup; + +static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext, + const struct btf_dedup_opts *opts); +static void btf_dedup_free(struct btf_dedup *d); +static int btf_dedup_strings(struct btf_dedup *d); +static int btf_dedup_prim_types(struct btf_dedup *d); +static int btf_dedup_struct_types(struct btf_dedup *d); +static int btf_dedup_ref_types(struct btf_dedup *d); +static int btf_dedup_compact_types(struct btf_dedup *d); +static int btf_dedup_remap_types(struct btf_dedup *d); + +/* + * Deduplicate BTF types and strings. + * + * BTF dedup algorithm takes as an input `struct btf` representing `.BTF` ELF + * section with all BTF type descriptors and string data. It overwrites that + * memory in-place with deduplicated types and strings without any loss of + * information. If optional `struct btf_ext` representing '.BTF.ext' ELF section + * is provided, all the strings referenced from .BTF.ext section are honored + * and updated to point to the right offsets after deduplication. + * + * If function returns with error, type/string data might be garbled and should + * be discarded. + * + * More verbose and detailed description of both problem btf_dedup is solving, + * as well as solution could be found at: + * https://facebookmicrosites.github.io/bpf/blog/2018/11/14/btf-enhancement.html + * + * Problem description and justification + * ===================================== + * + * BTF type information is typically emitted either as a result of conversion + * from DWARF to BTF or directly by compiler. In both cases, each compilation + * unit contains information about a subset of all the types that are used + * in an application. These subsets are frequently overlapping and contain a lot + * of duplicated information when later concatenated together into a single + * binary. This algorithm ensures that each unique type is represented by single + * BTF type descriptor, greatly reducing resulting size of BTF data. + * + * Compilation unit isolation and subsequent duplication of data is not the only + * problem. The same type hierarchy (e.g., struct and all the type that struct + * references) in different compilation units can be represented in BTF to + * various degrees of completeness (or, rather, incompleteness) due to + * struct/union forward declarations. + * + * Let's take a look at an example, that we'll use to better understand the + * problem (and solution). Suppose we have two compilation units, each using + * same `struct S`, but each of them having incomplete type information about + * struct's fields: + * + * // CU #1: + * struct S; + * struct A { + * int a; + * struct A* self; + * struct S* parent; + * }; + * struct B; + * struct S { + * struct A* a_ptr; + * struct B* b_ptr; + * }; + * + * // CU #2: + * struct S; + * struct A; + * struct B { + * int b; + * struct B* self; + * struct S* parent; + * }; + * struct S { + * struct A* a_ptr; + * struct B* b_ptr; + * }; + * + * In case of CU #1, BTF data will know only that `struct B` exist (but no + * more), but will know the complete type information about `struct A`. While + * for CU #2, it will know full type information about `struct B`, but will + * only know about forward declaration of `struct A` (in BTF terms, it will + * have `BTF_KIND_FWD` type descriptor with name `B`). + * + * This compilation unit isolation means that it's possible that there is no + * single CU with complete type information describing structs `S`, `A`, and + * `B`. Also, we might get tons of duplicated and redundant type information. + * + * Additional complication we need to keep in mind comes from the fact that + * types, in general, can form graphs containing cycles, not just DAGs. + * + * While algorithm does deduplication, it also merges and resolves type + * information (unless disabled throught `struct btf_opts`), whenever possible. + * E.g., in the example above with two compilation units having partial type + * information for structs `A` and `B`, the output of algorithm will emit + * a single copy of each BTF type that describes structs `A`, `B`, and `S` + * (as well as type information for `int` and pointers), as if they were defined + * in a single compilation unit as: + * + * struct A { + * int a; + * struct A* self; + * struct S* parent; + * }; + * struct B { + * int b; + * struct B* self; + * struct S* parent; + * }; + * struct S { + * struct A* a_ptr; + * struct B* b_ptr; + * }; + * + * Algorithm summary + * ================= + * + * Algorithm completes its work in 6 separate passes: + * + * 1. Strings deduplication. + * 2. Primitive types deduplication (int, enum, fwd). + * 3. Struct/union types deduplication. + * 4. Reference types deduplication (pointers, typedefs, arrays, funcs, func + * protos, and const/volatile/restrict modifiers). + * 5. Types compaction. + * 6. Types remapping. + * + * Algorithm determines canonical type descriptor, which is a single + * representative type for each truly unique type. This canonical type is the + * one that will go into final deduplicated BTF type information. For + * struct/unions, it is also the type that algorithm will merge additional type + * information into (while resolving FWDs), as it discovers it from data in + * other CUs. Each input BTF type eventually gets either mapped to itself, if + * that type is canonical, or to some other type, if that type is equivalent + * and was chosen as canonical representative. This mapping is stored in + * `btf_dedup->map` array. This map is also used to record STRUCT/UNION that + * FWD type got resolved to. + * + * To facilitate fast discovery of canonical types, we also maintain canonical + * index (`btf_dedup->dedup_table`), which maps type descriptor's signature hash + * (i.e., hashed kind, name, size, fields, etc) into a list of canonical types + * that match that signature. With sufficiently good choice of type signature + * hashing function, we can limit number of canonical types for each unique type + * signature to a very small number, allowing to find canonical type for any + * duplicated type very quickly. + * + * Struct/union deduplication is the most critical part and algorithm for + * deduplicating structs/unions is described in greater details in comments for + * `btf_dedup_is_equiv` function. + */ +int btf__dedup(struct btf *btf, struct btf_ext *btf_ext, + const struct btf_dedup_opts *opts) +{ + struct btf_dedup *d = btf_dedup_new(btf, btf_ext, opts); + int err; + + if (IS_ERR(d)) { + pr_debug("btf_dedup_new failed: %ld", PTR_ERR(d)); + return -EINVAL; + } + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + err = btf_dedup_strings(d); + if (err < 0) { + pr_debug("btf_dedup_strings failed:%d\n", err); + goto done; + } + err = btf_dedup_prim_types(d); + if (err < 0) { + pr_debug("btf_dedup_prim_types failed:%d\n", err); + goto done; + } + err = btf_dedup_struct_types(d); + if (err < 0) { + pr_debug("btf_dedup_struct_types failed:%d\n", err); + goto done; + } + err = btf_dedup_ref_types(d); + if (err < 0) { + pr_debug("btf_dedup_ref_types failed:%d\n", err); + goto done; + } + err = btf_dedup_compact_types(d); + if (err < 0) { + pr_debug("btf_dedup_compact_types failed:%d\n", err); + goto done; + } + err = btf_dedup_remap_types(d); + if (err < 0) { + pr_debug("btf_dedup_remap_types failed:%d\n", err); + goto done; + } + +done: + btf_dedup_free(d); + return err; +} + +#define BTF_UNPROCESSED_ID ((__u32)-1) +#define BTF_IN_PROGRESS_ID ((__u32)-2) + +struct btf_dedup { + /* .BTF section to be deduped in-place */ + struct btf *btf; + /* + * Optional .BTF.ext section. When provided, any strings referenced + * from it will be taken into account when deduping strings + */ + struct btf_ext *btf_ext; + /* + * This is a map from any type's signature hash to a list of possible + * canonical representative type candidates. Hash collisions are + * ignored, so even types of various kinds can share same list of + * candidates, which is fine because we rely on subsequent + * btf_xxx_equal() checks to authoritatively verify type equality. + */ + struct hashmap *dedup_table; + /* Canonical types map */ + __u32 *map; + /* Hypothetical mapping, used during type graph equivalence checks */ + __u32 *hypot_map; + __u32 *hypot_list; + size_t hypot_cnt; + size_t hypot_cap; + /* Various option modifying behavior of algorithm */ + struct btf_dedup_opts opts; +}; + +struct btf_str_ptr { + const char *str; + __u32 new_off; + bool used; +}; + +struct btf_str_ptrs { + struct btf_str_ptr *ptrs; + const char *data; + __u32 cnt; + __u32 cap; +}; + +static long hash_combine(long h, long value) +{ + return h * 31 + value; +} + +#define for_each_dedup_cand(d, node, hash) \ + hashmap__for_each_key_entry(d->dedup_table, node, (void *)hash) + +static int btf_dedup_table_add(struct btf_dedup *d, long hash, __u32 type_id) +{ + return hashmap__append(d->dedup_table, + (void *)hash, (void *)(long)type_id); +} + +static int btf_dedup_hypot_map_add(struct btf_dedup *d, + __u32 from_id, __u32 to_id) +{ + if (d->hypot_cnt == d->hypot_cap) { + __u32 *new_list; + + d->hypot_cap += max((size_t)16, d->hypot_cap / 2); + new_list = libbpf_reallocarray(d->hypot_list, d->hypot_cap, sizeof(__u32)); + if (!new_list) + return -ENOMEM; + d->hypot_list = new_list; + } + d->hypot_list[d->hypot_cnt++] = from_id; + d->hypot_map[from_id] = to_id; + return 0; +} + +static void btf_dedup_clear_hypot_map(struct btf_dedup *d) +{ + int i; + + for (i = 0; i < d->hypot_cnt; i++) + d->hypot_map[d->hypot_list[i]] = BTF_UNPROCESSED_ID; + d->hypot_cnt = 0; +} + +static void btf_dedup_free(struct btf_dedup *d) +{ + hashmap__free(d->dedup_table); + d->dedup_table = NULL; + + free(d->map); + d->map = NULL; + + free(d->hypot_map); + d->hypot_map = NULL; + + free(d->hypot_list); + d->hypot_list = NULL; + + free(d); +} + +static size_t btf_dedup_identity_hash_fn(const void *key, void *ctx) +{ + return (size_t)key; +} + +static size_t btf_dedup_collision_hash_fn(const void *key, void *ctx) +{ + return 0; +} + +static bool btf_dedup_equal_fn(const void *k1, const void *k2, void *ctx) +{ + return k1 == k2; +} + +static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext, + const struct btf_dedup_opts *opts) +{ + struct btf_dedup *d = calloc(1, sizeof(struct btf_dedup)); + hashmap_hash_fn hash_fn = btf_dedup_identity_hash_fn; + int i, err = 0; + + if (!d) + return ERR_PTR(-ENOMEM); + + d->opts.dont_resolve_fwds = opts && opts->dont_resolve_fwds; + /* dedup_table_size is now used only to force collisions in tests */ + if (opts && opts->dedup_table_size == 1) + hash_fn = btf_dedup_collision_hash_fn; + + d->btf = btf; + d->btf_ext = btf_ext; + + d->dedup_table = hashmap__new(hash_fn, btf_dedup_equal_fn, NULL); + if (IS_ERR(d->dedup_table)) { + err = PTR_ERR(d->dedup_table); + d->dedup_table = NULL; + goto done; + } + + d->map = malloc(sizeof(__u32) * (1 + btf->nr_types)); + if (!d->map) { + err = -ENOMEM; + goto done; + } + /* special BTF "void" type is made canonical immediately */ + d->map[0] = 0; + for (i = 1; i <= btf->nr_types; i++) { + struct btf_type *t = btf_type_by_id(d->btf, i); + + /* VAR and DATASEC are never deduped and are self-canonical */ + if (btf_is_var(t) || btf_is_datasec(t)) + d->map[i] = i; + else + d->map[i] = BTF_UNPROCESSED_ID; + } + + d->hypot_map = malloc(sizeof(__u32) * (1 + btf->nr_types)); + if (!d->hypot_map) { + err = -ENOMEM; + goto done; + } + for (i = 0; i <= btf->nr_types; i++) + d->hypot_map[i] = BTF_UNPROCESSED_ID; + +done: + if (err) { + btf_dedup_free(d); + return ERR_PTR(err); + } + + return d; +} + +typedef int (*str_off_fn_t)(__u32 *str_off_ptr, void *ctx); + +/* + * Iterate over all possible places in .BTF and .BTF.ext that can reference + * string and pass pointer to it to a provided callback `fn`. + */ +static int btf_for_each_str_off(struct btf_dedup *d, str_off_fn_t fn, void *ctx) +{ + void *line_data_cur, *line_data_end; + int i, j, r, rec_size; + struct btf_type *t; + + for (i = 1; i <= d->btf->nr_types; i++) { + t = btf_type_by_id(d->btf, i); + r = fn(&t->name_off, ctx); + if (r) + return r; + + switch (btf_kind(t)) { + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: { + struct btf_member *m = btf_members(t); + __u16 vlen = btf_vlen(t); + + for (j = 0; j < vlen; j++) { + r = fn(&m->name_off, ctx); + if (r) + return r; + m++; + } + break; + } + case BTF_KIND_ENUM: { + struct btf_enum *m = btf_enum(t); + __u16 vlen = btf_vlen(t); + + for (j = 0; j < vlen; j++) { + r = fn(&m->name_off, ctx); + if (r) + return r; + m++; + } + break; + } + case BTF_KIND_FUNC_PROTO: { + struct btf_param *m = btf_params(t); + __u16 vlen = btf_vlen(t); + + for (j = 0; j < vlen; j++) { + r = fn(&m->name_off, ctx); + if (r) + return r; + m++; + } + break; + } + default: + break; + } + } + + if (!d->btf_ext) + return 0; + + line_data_cur = d->btf_ext->line_info.info; + line_data_end = d->btf_ext->line_info.info + d->btf_ext->line_info.len; + rec_size = d->btf_ext->line_info.rec_size; + + while (line_data_cur < line_data_end) { + struct btf_ext_info_sec *sec = line_data_cur; + struct bpf_line_info_min *line_info; + __u32 num_info = sec->num_info; + + r = fn(&sec->sec_name_off, ctx); + if (r) + return r; + + line_data_cur += sizeof(struct btf_ext_info_sec); + for (i = 0; i < num_info; i++) { + line_info = line_data_cur; + r = fn(&line_info->file_name_off, ctx); + if (r) + return r; + r = fn(&line_info->line_off, ctx); + if (r) + return r; + line_data_cur += rec_size; + } + } + + return 0; +} + +static int str_sort_by_content(const void *a1, const void *a2) +{ + const struct btf_str_ptr *p1 = a1; + const struct btf_str_ptr *p2 = a2; + + return strcmp(p1->str, p2->str); +} + +static int str_sort_by_offset(const void *a1, const void *a2) +{ + const struct btf_str_ptr *p1 = a1; + const struct btf_str_ptr *p2 = a2; + + if (p1->str != p2->str) + return p1->str < p2->str ? -1 : 1; + return 0; +} + +static int btf_dedup_str_ptr_cmp(const void *str_ptr, const void *pelem) +{ + const struct btf_str_ptr *p = pelem; + + if (str_ptr != p->str) + return (const char *)str_ptr < p->str ? -1 : 1; + return 0; +} + +static int btf_str_mark_as_used(__u32 *str_off_ptr, void *ctx) +{ + struct btf_str_ptrs *strs; + struct btf_str_ptr *s; + + if (*str_off_ptr == 0) + return 0; + + strs = ctx; + s = bsearch(strs->data + *str_off_ptr, strs->ptrs, strs->cnt, + sizeof(struct btf_str_ptr), btf_dedup_str_ptr_cmp); + if (!s) + return -EINVAL; + s->used = true; + return 0; +} + +static int btf_str_remap_offset(__u32 *str_off_ptr, void *ctx) +{ + struct btf_str_ptrs *strs; + struct btf_str_ptr *s; + + if (*str_off_ptr == 0) + return 0; + + strs = ctx; + s = bsearch(strs->data + *str_off_ptr, strs->ptrs, strs->cnt, + sizeof(struct btf_str_ptr), btf_dedup_str_ptr_cmp); + if (!s) + return -EINVAL; + *str_off_ptr = s->new_off; + return 0; +} + +/* + * Dedup string and filter out those that are not referenced from either .BTF + * or .BTF.ext (if provided) sections. + * + * This is done by building index of all strings in BTF's string section, + * then iterating over all entities that can reference strings (e.g., type + * names, struct field names, .BTF.ext line info, etc) and marking corresponding + * strings as used. After that all used strings are deduped and compacted into + * sequential blob of memory and new offsets are calculated. Then all the string + * references are iterated again and rewritten using new offsets. + */ +static int btf_dedup_strings(struct btf_dedup *d) +{ + char *start = d->btf->strs_data; + char *end = start + d->btf->hdr->str_len; + char *p = start, *tmp_strs = NULL; + struct btf_str_ptrs strs = { + .cnt = 0, + .cap = 0, + .ptrs = NULL, + .data = start, + }; + int i, j, err = 0, grp_idx; + bool grp_used; + + if (d->btf->strs_deduped) + return 0; + + /* build index of all strings */ + while (p < end) { + if (strs.cnt + 1 > strs.cap) { + struct btf_str_ptr *new_ptrs; + + strs.cap += max(strs.cnt / 2, 16U); + new_ptrs = libbpf_reallocarray(strs.ptrs, strs.cap, sizeof(strs.ptrs[0])); + if (!new_ptrs) { + err = -ENOMEM; + goto done; + } + strs.ptrs = new_ptrs; + } + + strs.ptrs[strs.cnt].str = p; + strs.ptrs[strs.cnt].used = false; + + p += strlen(p) + 1; + strs.cnt++; + } + + /* temporary storage for deduplicated strings */ + tmp_strs = malloc(d->btf->hdr->str_len); + if (!tmp_strs) { + err = -ENOMEM; + goto done; + } + + /* mark all used strings */ + strs.ptrs[0].used = true; + err = btf_for_each_str_off(d, btf_str_mark_as_used, &strs); + if (err) + goto done; + + /* sort strings by context, so that we can identify duplicates */ + qsort(strs.ptrs, strs.cnt, sizeof(strs.ptrs[0]), str_sort_by_content); + + /* + * iterate groups of equal strings and if any instance in a group was + * referenced, emit single instance and remember new offset + */ + p = tmp_strs; + grp_idx = 0; + grp_used = strs.ptrs[0].used; + /* iterate past end to avoid code duplication after loop */ + for (i = 1; i <= strs.cnt; i++) { + /* + * when i == strs.cnt, we want to skip string comparison and go + * straight to handling last group of strings (otherwise we'd + * need to handle last group after the loop w/ duplicated code) + */ + if (i < strs.cnt && + !strcmp(strs.ptrs[i].str, strs.ptrs[grp_idx].str)) { + grp_used = grp_used || strs.ptrs[i].used; + continue; + } + + /* + * this check would have been required after the loop to handle + * last group of strings, but due to <= condition in a loop + * we avoid that duplication + */ + if (grp_used) { + int new_off = p - tmp_strs; + __u32 len = strlen(strs.ptrs[grp_idx].str); + + memmove(p, strs.ptrs[grp_idx].str, len + 1); + for (j = grp_idx; j < i; j++) + strs.ptrs[j].new_off = new_off; + p += len + 1; + } + + if (i < strs.cnt) { + grp_idx = i; + grp_used = strs.ptrs[i].used; + } + } + + /* replace original strings with deduped ones */ + d->btf->hdr->str_len = p - tmp_strs; + memmove(start, tmp_strs, d->btf->hdr->str_len); + end = start + d->btf->hdr->str_len; + + /* restore original order for further binary search lookups */ + qsort(strs.ptrs, strs.cnt, sizeof(strs.ptrs[0]), str_sort_by_offset); + + /* remap string offsets */ + err = btf_for_each_str_off(d, btf_str_remap_offset, &strs); + if (err) + goto done; + + d->btf->hdr->str_len = end - start; + d->btf->strs_deduped = true; + +done: + free(tmp_strs); + free(strs.ptrs); + return err; +} + +static long btf_hash_common(struct btf_type *t) +{ + long h; + + h = hash_combine(0, t->name_off); + h = hash_combine(h, t->info); + h = hash_combine(h, t->size); + return h; +} + +static bool btf_equal_common(struct btf_type *t1, struct btf_type *t2) +{ + return t1->name_off == t2->name_off && + t1->info == t2->info && + t1->size == t2->size; +} + +/* Calculate type signature hash of INT. */ +static long btf_hash_int(struct btf_type *t) +{ + __u32 info = *(__u32 *)(t + 1); + long h; + + h = btf_hash_common(t); + h = hash_combine(h, info); + return h; +} + +/* Check structural equality of two INTs. */ +static bool btf_equal_int(struct btf_type *t1, struct btf_type *t2) +{ + __u32 info1, info2; + + if (!btf_equal_common(t1, t2)) + return false; + info1 = *(__u32 *)(t1 + 1); + info2 = *(__u32 *)(t2 + 1); + return info1 == info2; +} + +/* Calculate type signature hash of ENUM. */ +static long btf_hash_enum(struct btf_type *t) +{ + long h; + + /* don't hash vlen and enum members to support enum fwd resolving */ + h = hash_combine(0, t->name_off); + h = hash_combine(h, t->info & ~0xffff); + h = hash_combine(h, t->size); + return h; +} + +/* Check structural equality of two ENUMs. */ +static bool btf_equal_enum(struct btf_type *t1, struct btf_type *t2) +{ + const struct btf_enum *m1, *m2; + __u16 vlen; + int i; + + if (!btf_equal_common(t1, t2)) + return false; + + vlen = btf_vlen(t1); + m1 = btf_enum(t1); + m2 = btf_enum(t2); + for (i = 0; i < vlen; i++) { + if (m1->name_off != m2->name_off || m1->val != m2->val) + return false; + m1++; + m2++; + } + return true; +} + +static inline bool btf_is_enum_fwd(struct btf_type *t) +{ + return btf_is_enum(t) && btf_vlen(t) == 0; +} + +static bool btf_compat_enum(struct btf_type *t1, struct btf_type *t2) +{ + if (!btf_is_enum_fwd(t1) && !btf_is_enum_fwd(t2)) + return btf_equal_enum(t1, t2); + /* ignore vlen when comparing */ + return t1->name_off == t2->name_off && + (t1->info & ~0xffff) == (t2->info & ~0xffff) && + t1->size == t2->size; +} + +/* + * Calculate type signature hash of STRUCT/UNION, ignoring referenced type IDs, + * as referenced type IDs equivalence is established separately during type + * graph equivalence check algorithm. + */ +static long btf_hash_struct(struct btf_type *t) +{ + const struct btf_member *member = btf_members(t); + __u32 vlen = btf_vlen(t); + long h = btf_hash_common(t); + int i; + + for (i = 0; i < vlen; i++) { + h = hash_combine(h, member->name_off); + h = hash_combine(h, member->offset); + /* no hashing of referenced type ID, it can be unresolved yet */ + member++; + } + return h; +} + +/* + * Check structural compatibility of two FUNC_PROTOs, ignoring referenced type + * IDs. This check is performed during type graph equivalence check and + * referenced types equivalence is checked separately. + */ +static bool btf_shallow_equal_struct(struct btf_type *t1, struct btf_type *t2) +{ + const struct btf_member *m1, *m2; + __u16 vlen; + int i; + + if (!btf_equal_common(t1, t2)) + return false; + + vlen = btf_vlen(t1); + m1 = btf_members(t1); + m2 = btf_members(t2); + for (i = 0; i < vlen; i++) { + if (m1->name_off != m2->name_off || m1->offset != m2->offset) + return false; + m1++; + m2++; + } + return true; +} + +/* + * Calculate type signature hash of ARRAY, including referenced type IDs, + * under assumption that they were already resolved to canonical type IDs and + * are not going to change. + */ +static long btf_hash_array(struct btf_type *t) +{ + const struct btf_array *info = btf_array(t); + long h = btf_hash_common(t); + + h = hash_combine(h, info->type); + h = hash_combine(h, info->index_type); + h = hash_combine(h, info->nelems); + return h; +} + +/* + * Check exact equality of two ARRAYs, taking into account referenced + * type IDs, under assumption that they were already resolved to canonical + * type IDs and are not going to change. + * This function is called during reference types deduplication to compare + * ARRAY to potential canonical representative. + */ +static bool btf_equal_array(struct btf_type *t1, struct btf_type *t2) +{ + const struct btf_array *info1, *info2; + + if (!btf_equal_common(t1, t2)) + return false; + + info1 = btf_array(t1); + info2 = btf_array(t2); + return info1->type == info2->type && + info1->index_type == info2->index_type && + info1->nelems == info2->nelems; +} + +/* + * Check structural compatibility of two ARRAYs, ignoring referenced type + * IDs. This check is performed during type graph equivalence check and + * referenced types equivalence is checked separately. + */ +static bool btf_compat_array(struct btf_type *t1, struct btf_type *t2) +{ + if (!btf_equal_common(t1, t2)) + return false; + + return btf_array(t1)->nelems == btf_array(t2)->nelems; +} + +/* + * Calculate type signature hash of FUNC_PROTO, including referenced type IDs, + * under assumption that they were already resolved to canonical type IDs and + * are not going to change. + */ +static long btf_hash_fnproto(struct btf_type *t) +{ + const struct btf_param *member = btf_params(t); + __u16 vlen = btf_vlen(t); + long h = btf_hash_common(t); + int i; + + for (i = 0; i < vlen; i++) { + h = hash_combine(h, member->name_off); + h = hash_combine(h, member->type); + member++; + } + return h; +} + +/* + * Check exact equality of two FUNC_PROTOs, taking into account referenced + * type IDs, under assumption that they were already resolved to canonical + * type IDs and are not going to change. + * This function is called during reference types deduplication to compare + * FUNC_PROTO to potential canonical representative. + */ +static bool btf_equal_fnproto(struct btf_type *t1, struct btf_type *t2) +{ + const struct btf_param *m1, *m2; + __u16 vlen; + int i; + + if (!btf_equal_common(t1, t2)) + return false; + + vlen = btf_vlen(t1); + m1 = btf_params(t1); + m2 = btf_params(t2); + for (i = 0; i < vlen; i++) { + if (m1->name_off != m2->name_off || m1->type != m2->type) + return false; + m1++; + m2++; + } + return true; +} + +/* + * Check structural compatibility of two FUNC_PROTOs, ignoring referenced type + * IDs. This check is performed during type graph equivalence check and + * referenced types equivalence is checked separately. + */ +static bool btf_compat_fnproto(struct btf_type *t1, struct btf_type *t2) +{ + const struct btf_param *m1, *m2; + __u16 vlen; + int i; + + /* skip return type ID */ + if (t1->name_off != t2->name_off || t1->info != t2->info) + return false; + + vlen = btf_vlen(t1); + m1 = btf_params(t1); + m2 = btf_params(t2); + for (i = 0; i < vlen; i++) { + if (m1->name_off != m2->name_off) + return false; + m1++; + m2++; + } + return true; +} + +/* + * Deduplicate primitive types, that can't reference other types, by calculating + * their type signature hash and comparing them with any possible canonical + * candidate. If no canonical candidate matches, type itself is marked as + * canonical and is added into `btf_dedup->dedup_table` as another candidate. + */ +static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) +{ + struct btf_type *t = btf_type_by_id(d->btf, type_id); + struct hashmap_entry *hash_entry; + struct btf_type *cand; + /* if we don't find equivalent type, then we are canonical */ + __u32 new_id = type_id; + __u32 cand_id; + long h; + + switch (btf_kind(t)) { + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_ARRAY: + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + case BTF_KIND_FUNC: + case BTF_KIND_FUNC_PROTO: + case BTF_KIND_VAR: + case BTF_KIND_DATASEC: + return 0; + + case BTF_KIND_INT: + h = btf_hash_int(t); + for_each_dedup_cand(d, hash_entry, h) { + cand_id = (__u32)(long)hash_entry->value; + cand = btf_type_by_id(d->btf, cand_id); + if (btf_equal_int(t, cand)) { + new_id = cand_id; + break; + } + } + break; + + case BTF_KIND_ENUM: + h = btf_hash_enum(t); + for_each_dedup_cand(d, hash_entry, h) { + cand_id = (__u32)(long)hash_entry->value; + cand = btf_type_by_id(d->btf, cand_id); + if (btf_equal_enum(t, cand)) { + new_id = cand_id; + break; + } + if (d->opts.dont_resolve_fwds) + continue; + if (btf_compat_enum(t, cand)) { + if (btf_is_enum_fwd(t)) { + /* resolve fwd to full enum */ + new_id = cand_id; + break; + } + /* resolve canonical enum fwd to full enum */ + d->map[cand_id] = type_id; + } + } + break; + + case BTF_KIND_FWD: + h = btf_hash_common(t); + for_each_dedup_cand(d, hash_entry, h) { + cand_id = (__u32)(long)hash_entry->value; + cand = btf_type_by_id(d->btf, cand_id); + if (btf_equal_common(t, cand)) { + new_id = cand_id; + break; + } + } + break; + + default: + return -EINVAL; + } + + d->map[type_id] = new_id; + if (type_id == new_id && btf_dedup_table_add(d, h, type_id)) + return -ENOMEM; + + return 0; +} + +static int btf_dedup_prim_types(struct btf_dedup *d) +{ + int i, err; + + for (i = 1; i <= d->btf->nr_types; i++) { + err = btf_dedup_prim_type(d, i); + if (err) + return err; + } + return 0; +} + +/* + * Check whether type is already mapped into canonical one (could be to itself). + */ +static inline bool is_type_mapped(struct btf_dedup *d, uint32_t type_id) +{ + return d->map[type_id] <= BTF_MAX_NR_TYPES; +} + +/* + * Resolve type ID into its canonical type ID, if any; otherwise return original + * type ID. If type is FWD and is resolved into STRUCT/UNION already, follow + * STRUCT/UNION link and resolve it into canonical type ID as well. + */ +static inline __u32 resolve_type_id(struct btf_dedup *d, __u32 type_id) +{ + while (is_type_mapped(d, type_id) && d->map[type_id] != type_id) + type_id = d->map[type_id]; + return type_id; +} + +/* + * Resolve FWD to underlying STRUCT/UNION, if any; otherwise return original + * type ID. + */ +static uint32_t resolve_fwd_id(struct btf_dedup *d, uint32_t type_id) +{ + __u32 orig_type_id = type_id; + + if (!btf_is_fwd(btf__type_by_id(d->btf, type_id))) + return type_id; + + while (is_type_mapped(d, type_id) && d->map[type_id] != type_id) + type_id = d->map[type_id]; + + if (!btf_is_fwd(btf__type_by_id(d->btf, type_id))) + return type_id; + + return orig_type_id; +} + + +static inline __u16 btf_fwd_kind(struct btf_type *t) +{ + return btf_kflag(t) ? BTF_KIND_UNION : BTF_KIND_STRUCT; +} + +/* + * Check equivalence of BTF type graph formed by candidate struct/union (we'll + * call it "candidate graph" in this description for brevity) to a type graph + * formed by (potential) canonical struct/union ("canonical graph" for brevity + * here, though keep in mind that not all types in canonical graph are + * necessarily canonical representatives themselves, some of them might be + * duplicates or its uniqueness might not have been established yet). + * Returns: + * - >0, if type graphs are equivalent; + * - 0, if not equivalent; + * - <0, on error. + * + * Algorithm performs side-by-side DFS traversal of both type graphs and checks + * equivalence of BTF types at each step. If at any point BTF types in candidate + * and canonical graphs are not compatible structurally, whole graphs are + * incompatible. If types are structurally equivalent (i.e., all information + * except referenced type IDs is exactly the same), a mapping from `canon_id` to + * a `cand_id` is recored in hypothetical mapping (`btf_dedup->hypot_map`). + * If a type references other types, then those referenced types are checked + * for equivalence recursively. + * + * During DFS traversal, if we find that for current `canon_id` type we + * already have some mapping in hypothetical map, we check for two possible + * situations: + * - `canon_id` is mapped to exactly the same type as `cand_id`. This will + * happen when type graphs have cycles. In this case we assume those two + * types are equivalent. + * - `canon_id` is mapped to different type. This is contradiction in our + * hypothetical mapping, because same graph in canonical graph corresponds + * to two different types in candidate graph, which for equivalent type + * graphs shouldn't happen. This condition terminates equivalence check + * with negative result. + * + * If type graphs traversal exhausts types to check and find no contradiction, + * then type graphs are equivalent. + * + * When checking types for equivalence, there is one special case: FWD types. + * If FWD type resolution is allowed and one of the types (either from canonical + * or candidate graph) is FWD and other is STRUCT/UNION (depending on FWD's kind + * flag) and their names match, hypothetical mapping is updated to point from + * FWD to STRUCT/UNION. If graphs will be determined as equivalent successfully, + * this mapping will be used to record FWD -> STRUCT/UNION mapping permanently. + * + * Technically, this could lead to incorrect FWD to STRUCT/UNION resolution, + * if there are two exactly named (or anonymous) structs/unions that are + * compatible structurally, one of which has FWD field, while other is concrete + * STRUCT/UNION, but according to C sources they are different structs/unions + * that are referencing different types with the same name. This is extremely + * unlikely to happen, but btf_dedup API allows to disable FWD resolution if + * this logic is causing problems. + * + * Doing FWD resolution means that both candidate and/or canonical graphs can + * consists of portions of the graph that come from multiple compilation units. + * This is due to the fact that types within single compilation unit are always + * deduplicated and FWDs are already resolved, if referenced struct/union + * definiton is available. So, if we had unresolved FWD and found corresponding + * STRUCT/UNION, they will be from different compilation units. This + * consequently means that when we "link" FWD to corresponding STRUCT/UNION, + * type graph will likely have at least two different BTF types that describe + * same type (e.g., most probably there will be two different BTF types for the + * same 'int' primitive type) and could even have "overlapping" parts of type + * graph that describe same subset of types. + * + * This in turn means that our assumption that each type in canonical graph + * must correspond to exactly one type in candidate graph might not hold + * anymore and will make it harder to detect contradictions using hypothetical + * map. To handle this problem, we allow to follow FWD -> STRUCT/UNION + * resolution only in canonical graph. FWDs in candidate graphs are never + * resolved. To see why it's OK, let's check all possible situations w.r.t. FWDs + * that can occur: + * - Both types in canonical and candidate graphs are FWDs. If they are + * structurally equivalent, then they can either be both resolved to the + * same STRUCT/UNION or not resolved at all. In both cases they are + * equivalent and there is no need to resolve FWD on candidate side. + * - Both types in canonical and candidate graphs are concrete STRUCT/UNION, + * so nothing to resolve as well, algorithm will check equivalence anyway. + * - Type in canonical graph is FWD, while type in candidate is concrete + * STRUCT/UNION. In this case candidate graph comes from single compilation + * unit, so there is exactly one BTF type for each unique C type. After + * resolving FWD into STRUCT/UNION, there might be more than one BTF type + * in canonical graph mapping to single BTF type in candidate graph, but + * because hypothetical mapping maps from canonical to candidate types, it's + * alright, and we still maintain the property of having single `canon_id` + * mapping to single `cand_id` (there could be two different `canon_id` + * mapped to the same `cand_id`, but it's not contradictory). + * - Type in canonical graph is concrete STRUCT/UNION, while type in candidate + * graph is FWD. In this case we are just going to check compatibility of + * STRUCT/UNION and corresponding FWD, and if they are compatible, we'll + * assume that whatever STRUCT/UNION FWD resolves to must be equivalent to + * a concrete STRUCT/UNION from canonical graph. If the rest of type graphs + * turn out equivalent, we'll re-resolve FWD to concrete STRUCT/UNION from + * canonical graph. + */ +static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, + __u32 canon_id) +{ + struct btf_type *cand_type; + struct btf_type *canon_type; + __u32 hypot_type_id; + __u16 cand_kind; + __u16 canon_kind; + int i, eq; + + /* if both resolve to the same canonical, they must be equivalent */ + if (resolve_type_id(d, cand_id) == resolve_type_id(d, canon_id)) + return 1; + + canon_id = resolve_fwd_id(d, canon_id); + + hypot_type_id = d->hypot_map[canon_id]; + if (hypot_type_id <= BTF_MAX_NR_TYPES) + return hypot_type_id == cand_id; + + if (btf_dedup_hypot_map_add(d, canon_id, cand_id)) + return -ENOMEM; + + cand_type = btf_type_by_id(d->btf, cand_id); + canon_type = btf_type_by_id(d->btf, canon_id); + cand_kind = btf_kind(cand_type); + canon_kind = btf_kind(canon_type); + + if (cand_type->name_off != canon_type->name_off) + return 0; + + /* FWD <--> STRUCT/UNION equivalence check, if enabled */ + if (!d->opts.dont_resolve_fwds + && (cand_kind == BTF_KIND_FWD || canon_kind == BTF_KIND_FWD) + && cand_kind != canon_kind) { + __u16 real_kind; + __u16 fwd_kind; + + if (cand_kind == BTF_KIND_FWD) { + real_kind = canon_kind; + fwd_kind = btf_fwd_kind(cand_type); + } else { + real_kind = cand_kind; + fwd_kind = btf_fwd_kind(canon_type); + } + return fwd_kind == real_kind; + } + + if (cand_kind != canon_kind) + return 0; + + switch (cand_kind) { + case BTF_KIND_INT: + return btf_equal_int(cand_type, canon_type); + + case BTF_KIND_ENUM: + if (d->opts.dont_resolve_fwds) + return btf_equal_enum(cand_type, canon_type); + else + return btf_compat_enum(cand_type, canon_type); + + case BTF_KIND_FWD: + return btf_equal_common(cand_type, canon_type); + + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + if (cand_type->info != canon_type->info) + return 0; + return btf_dedup_is_equiv(d, cand_type->type, canon_type->type); + + case BTF_KIND_ARRAY: { + const struct btf_array *cand_arr, *canon_arr; + + if (!btf_compat_array(cand_type, canon_type)) + return 0; + cand_arr = btf_array(cand_type); + canon_arr = btf_array(canon_type); + eq = btf_dedup_is_equiv(d, + cand_arr->index_type, canon_arr->index_type); + if (eq <= 0) + return eq; + return btf_dedup_is_equiv(d, cand_arr->type, canon_arr->type); + } + + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: { + const struct btf_member *cand_m, *canon_m; + __u16 vlen; + + if (!btf_shallow_equal_struct(cand_type, canon_type)) + return 0; + vlen = btf_vlen(cand_type); + cand_m = btf_members(cand_type); + canon_m = btf_members(canon_type); + for (i = 0; i < vlen; i++) { + eq = btf_dedup_is_equiv(d, cand_m->type, canon_m->type); + if (eq <= 0) + return eq; + cand_m++; + canon_m++; + } + + return 1; + } + + case BTF_KIND_FUNC_PROTO: { + const struct btf_param *cand_p, *canon_p; + __u16 vlen; + + if (!btf_compat_fnproto(cand_type, canon_type)) + return 0; + eq = btf_dedup_is_equiv(d, cand_type->type, canon_type->type); + if (eq <= 0) + return eq; + vlen = btf_vlen(cand_type); + cand_p = btf_params(cand_type); + canon_p = btf_params(canon_type); + for (i = 0; i < vlen; i++) { + eq = btf_dedup_is_equiv(d, cand_p->type, canon_p->type); + if (eq <= 0) + return eq; + cand_p++; + canon_p++; + } + return 1; + } + + default: + return -EINVAL; + } + return 0; +} + +/* + * Use hypothetical mapping, produced by successful type graph equivalence + * check, to augment existing struct/union canonical mapping, where possible. + * + * If BTF_KIND_FWD resolution is allowed, this mapping is also used to record + * FWD -> STRUCT/UNION correspondence as well. FWD resolution is bidirectional: + * it doesn't matter if FWD type was part of canonical graph or candidate one, + * we are recording the mapping anyway. As opposed to carefulness required + * for struct/union correspondence mapping (described below), for FWD resolution + * it's not important, as by the time that FWD type (reference type) will be + * deduplicated all structs/unions will be deduped already anyway. + * + * Recording STRUCT/UNION mapping is purely a performance optimization and is + * not required for correctness. It needs to be done carefully to ensure that + * struct/union from candidate's type graph is not mapped into corresponding + * struct/union from canonical type graph that itself hasn't been resolved into + * canonical representative. The only guarantee we have is that canonical + * struct/union was determined as canonical and that won't change. But any + * types referenced through that struct/union fields could have been not yet + * resolved, so in case like that it's too early to establish any kind of + * correspondence between structs/unions. + * + * No canonical correspondence is derived for primitive types (they are already + * deduplicated completely already anyway) or reference types (they rely on + * stability of struct/union canonical relationship for equivalence checks). + */ +static void btf_dedup_merge_hypot_map(struct btf_dedup *d) +{ + __u32 cand_type_id, targ_type_id; + __u16 t_kind, c_kind; + __u32 t_id, c_id; + int i; + + for (i = 0; i < d->hypot_cnt; i++) { + cand_type_id = d->hypot_list[i]; + targ_type_id = d->hypot_map[cand_type_id]; + t_id = resolve_type_id(d, targ_type_id); + c_id = resolve_type_id(d, cand_type_id); + t_kind = btf_kind(btf__type_by_id(d->btf, t_id)); + c_kind = btf_kind(btf__type_by_id(d->btf, c_id)); + /* + * Resolve FWD into STRUCT/UNION. + * It's ok to resolve FWD into STRUCT/UNION that's not yet + * mapped to canonical representative (as opposed to + * STRUCT/UNION <--> STRUCT/UNION mapping logic below), because + * eventually that struct is going to be mapped and all resolved + * FWDs will automatically resolve to correct canonical + * representative. This will happen before ref type deduping, + * which critically depends on stability of these mapping. This + * stability is not a requirement for STRUCT/UNION equivalence + * checks, though. + */ + if (t_kind != BTF_KIND_FWD && c_kind == BTF_KIND_FWD) + d->map[c_id] = t_id; + else if (t_kind == BTF_KIND_FWD && c_kind != BTF_KIND_FWD) + d->map[t_id] = c_id; + + if ((t_kind == BTF_KIND_STRUCT || t_kind == BTF_KIND_UNION) && + c_kind != BTF_KIND_FWD && + is_type_mapped(d, c_id) && + !is_type_mapped(d, t_id)) { + /* + * as a perf optimization, we can map struct/union + * that's part of type graph we just verified for + * equivalence. We can do that for struct/union that has + * canonical representative only, though. + */ + d->map[t_id] = c_id; + } + } +} + +/* + * Deduplicate struct/union types. + * + * For each struct/union type its type signature hash is calculated, taking + * into account type's name, size, number, order and names of fields, but + * ignoring type ID's referenced from fields, because they might not be deduped + * completely until after reference types deduplication phase. This type hash + * is used to iterate over all potential canonical types, sharing same hash. + * For each canonical candidate we check whether type graphs that they form + * (through referenced types in fields and so on) are equivalent using algorithm + * implemented in `btf_dedup_is_equiv`. If such equivalence is found and + * BTF_KIND_FWD resolution is allowed, then hypothetical mapping + * (btf_dedup->hypot_map) produced by aforementioned type graph equivalence + * algorithm is used to record FWD -> STRUCT/UNION mapping. It's also used to + * potentially map other structs/unions to their canonical representatives, + * if such relationship hasn't yet been established. This speeds up algorithm + * by eliminating some of the duplicate work. + * + * If no matching canonical representative was found, struct/union is marked + * as canonical for itself and is added into btf_dedup->dedup_table hash map + * for further look ups. + */ +static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id) +{ + struct btf_type *cand_type, *t; + struct hashmap_entry *hash_entry; + /* if we don't find equivalent type, then we are canonical */ + __u32 new_id = type_id; + __u16 kind; + long h; + + /* already deduped or is in process of deduping (loop detected) */ + if (d->map[type_id] <= BTF_MAX_NR_TYPES) + return 0; + + t = btf_type_by_id(d->btf, type_id); + kind = btf_kind(t); + + if (kind != BTF_KIND_STRUCT && kind != BTF_KIND_UNION) + return 0; + + h = btf_hash_struct(t); + for_each_dedup_cand(d, hash_entry, h) { + __u32 cand_id = (__u32)(long)hash_entry->value; + int eq; + + /* + * Even though btf_dedup_is_equiv() checks for + * btf_shallow_equal_struct() internally when checking two + * structs (unions) for equivalence, we need to guard here + * from picking matching FWD type as a dedup candidate. + * This can happen due to hash collision. In such case just + * relying on btf_dedup_is_equiv() would lead to potentially + * creating a loop (FWD -> STRUCT and STRUCT -> FWD), because + * FWD and compatible STRUCT/UNION are considered equivalent. + */ + cand_type = btf_type_by_id(d->btf, cand_id); + if (!btf_shallow_equal_struct(t, cand_type)) + continue; + + btf_dedup_clear_hypot_map(d); + eq = btf_dedup_is_equiv(d, type_id, cand_id); + if (eq < 0) + return eq; + if (!eq) + continue; + new_id = cand_id; + btf_dedup_merge_hypot_map(d); + break; + } + + d->map[type_id] = new_id; + if (type_id == new_id && btf_dedup_table_add(d, h, type_id)) + return -ENOMEM; + + return 0; +} + +static int btf_dedup_struct_types(struct btf_dedup *d) +{ + int i, err; + + for (i = 1; i <= d->btf->nr_types; i++) { + err = btf_dedup_struct_type(d, i); + if (err) + return err; + } + return 0; +} + +/* + * Deduplicate reference type. + * + * Once all primitive and struct/union types got deduplicated, we can easily + * deduplicate all other (reference) BTF types. This is done in two steps: + * + * 1. Resolve all referenced type IDs into their canonical type IDs. This + * resolution can be done either immediately for primitive or struct/union types + * (because they were deduped in previous two phases) or recursively for + * reference types. Recursion will always terminate at either primitive or + * struct/union type, at which point we can "unwind" chain of reference types + * one by one. There is no danger of encountering cycles because in C type + * system the only way to form type cycle is through struct/union, so any chain + * of reference types, even those taking part in a type cycle, will inevitably + * reach struct/union at some point. + * + * 2. Once all referenced type IDs are resolved into canonical ones, BTF type + * becomes "stable", in the sense that no further deduplication will cause + * any changes to it. With that, it's now possible to calculate type's signature + * hash (this time taking into account referenced type IDs) and loop over all + * potential canonical representatives. If no match was found, current type + * will become canonical representative of itself and will be added into + * btf_dedup->dedup_table as another possible canonical representative. + */ +static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) +{ + struct hashmap_entry *hash_entry; + __u32 new_id = type_id, cand_id; + struct btf_type *t, *cand; + /* if we don't find equivalent type, then we are representative type */ + int ref_type_id; + long h; + + if (d->map[type_id] == BTF_IN_PROGRESS_ID) + return -ELOOP; + if (d->map[type_id] <= BTF_MAX_NR_TYPES) + return resolve_type_id(d, type_id); + + t = btf_type_by_id(d->btf, type_id); + d->map[type_id] = BTF_IN_PROGRESS_ID; + + switch (btf_kind(t)) { + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + ref_type_id = btf_dedup_ref_type(d, t->type); + if (ref_type_id < 0) + return ref_type_id; + t->type = ref_type_id; + + h = btf_hash_common(t); + for_each_dedup_cand(d, hash_entry, h) { + cand_id = (__u32)(long)hash_entry->value; + cand = btf_type_by_id(d->btf, cand_id); + if (btf_equal_common(t, cand)) { + new_id = cand_id; + break; + } + } + break; + + case BTF_KIND_ARRAY: { + struct btf_array *info = btf_array(t); + + ref_type_id = btf_dedup_ref_type(d, info->type); + if (ref_type_id < 0) + return ref_type_id; + info->type = ref_type_id; + + ref_type_id = btf_dedup_ref_type(d, info->index_type); + if (ref_type_id < 0) + return ref_type_id; + info->index_type = ref_type_id; + + h = btf_hash_array(t); + for_each_dedup_cand(d, hash_entry, h) { + cand_id = (__u32)(long)hash_entry->value; + cand = btf_type_by_id(d->btf, cand_id); + if (btf_equal_array(t, cand)) { + new_id = cand_id; + break; + } + } + break; + } + + case BTF_KIND_FUNC_PROTO: { + struct btf_param *param; + __u16 vlen; + int i; + + ref_type_id = btf_dedup_ref_type(d, t->type); + if (ref_type_id < 0) + return ref_type_id; + t->type = ref_type_id; + + vlen = btf_vlen(t); + param = btf_params(t); + for (i = 0; i < vlen; i++) { + ref_type_id = btf_dedup_ref_type(d, param->type); + if (ref_type_id < 0) + return ref_type_id; + param->type = ref_type_id; + param++; + } + + h = btf_hash_fnproto(t); + for_each_dedup_cand(d, hash_entry, h) { + cand_id = (__u32)(long)hash_entry->value; + cand = btf_type_by_id(d->btf, cand_id); + if (btf_equal_fnproto(t, cand)) { + new_id = cand_id; + break; + } + } + break; + } + + default: + return -EINVAL; + } + + d->map[type_id] = new_id; + if (type_id == new_id && btf_dedup_table_add(d, h, type_id)) + return -ENOMEM; + + return new_id; +} + +static int btf_dedup_ref_types(struct btf_dedup *d) +{ + int i, err; + + for (i = 1; i <= d->btf->nr_types; i++) { + err = btf_dedup_ref_type(d, i); + if (err < 0) + return err; + } + /* we won't need d->dedup_table anymore */ + hashmap__free(d->dedup_table); + d->dedup_table = NULL; + return 0; +} + +/* + * Compact types. + * + * After we established for each type its corresponding canonical representative + * type, we now can eliminate types that are not canonical and leave only + * canonical ones layed out sequentially in memory by copying them over + * duplicates. During compaction btf_dedup->hypot_map array is reused to store + * a map from original type ID to a new compacted type ID, which will be used + * during next phase to "fix up" type IDs, referenced from struct/union and + * reference types. + */ +static int btf_dedup_compact_types(struct btf_dedup *d) +{ + __u32 *new_offs; + __u32 next_type_id = 1; + void *p; + int i, len; + + /* we are going to reuse hypot_map to store compaction remapping */ + d->hypot_map[0] = 0; + for (i = 1; i <= d->btf->nr_types; i++) + d->hypot_map[i] = BTF_UNPROCESSED_ID; + + p = d->btf->types_data; + + for (i = 1; i <= d->btf->nr_types; i++) { + if (d->map[i] != i) + continue; + + len = btf_type_size(btf__type_by_id(d->btf, i)); + if (len < 0) + return len; + + memmove(p, btf__type_by_id(d->btf, i), len); + d->hypot_map[i] = next_type_id; + d->btf->type_offs[next_type_id] = p - d->btf->types_data; + p += len; + next_type_id++; + } + + /* shrink struct btf's internal types index and update btf_header */ + d->btf->nr_types = next_type_id - 1; + d->btf->type_offs_cap = d->btf->nr_types + 1; + d->btf->hdr->type_len = p - d->btf->types_data; + new_offs = libbpf_reallocarray(d->btf->type_offs, d->btf->type_offs_cap, + sizeof(*new_offs)); + if (!new_offs) + return -ENOMEM; + d->btf->type_offs = new_offs; + d->btf->hdr->str_off = d->btf->hdr->type_len; + d->btf->raw_size = d->btf->hdr->hdr_len + d->btf->hdr->type_len + d->btf->hdr->str_len; + return 0; +} + +/* + * Figure out final (deduplicated and compacted) type ID for provided original + * `type_id` by first resolving it into corresponding canonical type ID and + * then mapping it to a deduplicated type ID, stored in btf_dedup->hypot_map, + * which is populated during compaction phase. + */ +static int btf_dedup_remap_type_id(struct btf_dedup *d, __u32 type_id) +{ + __u32 resolved_type_id, new_type_id; + + resolved_type_id = resolve_type_id(d, type_id); + new_type_id = d->hypot_map[resolved_type_id]; + if (new_type_id > BTF_MAX_NR_TYPES) + return -EINVAL; + return new_type_id; +} + +/* + * Remap referenced type IDs into deduped type IDs. + * + * After BTF types are deduplicated and compacted, their final type IDs may + * differ from original ones. The map from original to a corresponding + * deduped type ID is stored in btf_dedup->hypot_map and is populated during + * compaction phase. During remapping phase we are rewriting all type IDs + * referenced from any BTF type (e.g., struct fields, func proto args, etc) to + * their final deduped type IDs. + */ +static int btf_dedup_remap_type(struct btf_dedup *d, __u32 type_id) +{ + struct btf_type *t = btf_type_by_id(d->btf, type_id); + int i, r; + + switch (btf_kind(t)) { + case BTF_KIND_INT: + case BTF_KIND_ENUM: + break; + + case BTF_KIND_FWD: + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + case BTF_KIND_VAR: + r = btf_dedup_remap_type_id(d, t->type); + if (r < 0) + return r; + t->type = r; + break; + + case BTF_KIND_ARRAY: { + struct btf_array *arr_info = btf_array(t); + + r = btf_dedup_remap_type_id(d, arr_info->type); + if (r < 0) + return r; + arr_info->type = r; + r = btf_dedup_remap_type_id(d, arr_info->index_type); + if (r < 0) + return r; + arr_info->index_type = r; + break; + } + + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: { + struct btf_member *member = btf_members(t); + __u16 vlen = btf_vlen(t); + + for (i = 0; i < vlen; i++) { + r = btf_dedup_remap_type_id(d, member->type); + if (r < 0) + return r; + member->type = r; + member++; + } + break; + } + + case BTF_KIND_FUNC_PROTO: { + struct btf_param *param = btf_params(t); + __u16 vlen = btf_vlen(t); + + r = btf_dedup_remap_type_id(d, t->type); + if (r < 0) + return r; + t->type = r; + + for (i = 0; i < vlen; i++) { + r = btf_dedup_remap_type_id(d, param->type); + if (r < 0) + return r; + param->type = r; + param++; + } + break; + } + + case BTF_KIND_DATASEC: { + struct btf_var_secinfo *var = btf_var_secinfos(t); + __u16 vlen = btf_vlen(t); + + for (i = 0; i < vlen; i++) { + r = btf_dedup_remap_type_id(d, var->type); + if (r < 0) + return r; + var->type = r; + var++; + } + break; + } + + default: + return -EINVAL; + } + + return 0; +} + +static int btf_dedup_remap_types(struct btf_dedup *d) +{ + int i, r; + + for (i = 1; i <= d->btf->nr_types; i++) { + r = btf_dedup_remap_type(d, i); + if (r < 0) + return r; + } + return 0; +} + +/* + * Probe few well-known locations for vmlinux kernel image and try to load BTF + * data out of it to use for target BTF. + */ +struct btf *libbpf_find_kernel_btf(void) +{ + struct { + const char *path_fmt; + bool raw_btf; + } locations[] = { + /* try canonical vmlinux BTF through sysfs first */ + { "/sys/kernel/btf/vmlinux", true /* raw BTF */ }, + /* fall back to trying to find vmlinux ELF on disk otherwise */ + { "/boot/vmlinux-%1$s" }, + { "/lib/modules/%1$s/vmlinux-%1$s" }, + { "/lib/modules/%1$s/build/vmlinux" }, + { "/usr/lib/modules/%1$s/kernel/vmlinux" }, + { "/usr/lib/debug/boot/vmlinux-%1$s" }, + { "/usr/lib/debug/boot/vmlinux-%1$s.debug" }, + { "/usr/lib/debug/lib/modules/%1$s/vmlinux" }, + }; + char path[PATH_MAX + 1]; + struct utsname buf; + struct btf *btf; + int i; + + uname(&buf); + + for (i = 0; i < ARRAY_SIZE(locations); i++) { + snprintf(path, PATH_MAX, locations[i].path_fmt, buf.release); + + if (access(path, R_OK)) + continue; + + if (locations[i].raw_btf) + btf = btf__parse_raw(path); + else + btf = btf__parse_elf(path, NULL); + + pr_debug("loading kernel BTF '%s': %ld\n", + path, IS_ERR(btf) ? PTR_ERR(btf) : 0); + if (IS_ERR(btf)) + continue; + + return btf; + } + + pr_warn("failed to find valid kernel BTF\n"); + return ERR_PTR(-ESRCH); +} diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h new file mode 100644 index 000000000..9cabc8b62 --- /dev/null +++ b/tools/lib/bpf/btf.h @@ -0,0 +1,361 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ +/* Copyright (c) 2018 Facebook */ + +#ifndef __LIBBPF_BTF_H +#define __LIBBPF_BTF_H + +#include <stdarg.h> +#include <stdbool.h> +#include <linux/btf.h> +#include <linux/types.h> + +#include "libbpf_common.h" + +#ifdef __cplusplus +extern "C" { +#endif + +#define BTF_ELF_SEC ".BTF" +#define BTF_EXT_ELF_SEC ".BTF.ext" +#define MAPS_ELF_SEC ".maps" + +struct btf; +struct btf_ext; +struct btf_type; + +struct bpf_object; + +enum btf_endianness { + BTF_LITTLE_ENDIAN = 0, + BTF_BIG_ENDIAN = 1, +}; + +LIBBPF_API void btf__free(struct btf *btf); +LIBBPF_API struct btf *btf__new(const void *data, __u32 size); +LIBBPF_API struct btf *btf__new_empty(void); +LIBBPF_API struct btf *btf__parse(const char *path, struct btf_ext **btf_ext); +LIBBPF_API struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext); +LIBBPF_API struct btf *btf__parse_raw(const char *path); +LIBBPF_API int btf__finalize_data(struct bpf_object *obj, struct btf *btf); +LIBBPF_API int btf__load(struct btf *btf); +LIBBPF_API __s32 btf__find_by_name(const struct btf *btf, + const char *type_name); +LIBBPF_API __s32 btf__find_by_name_kind(const struct btf *btf, + const char *type_name, __u32 kind); +LIBBPF_API __u32 btf__get_nr_types(const struct btf *btf); +LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf, + __u32 id); +LIBBPF_API size_t btf__pointer_size(const struct btf *btf); +LIBBPF_API int btf__set_pointer_size(struct btf *btf, size_t ptr_sz); +LIBBPF_API enum btf_endianness btf__endianness(const struct btf *btf); +LIBBPF_API int btf__set_endianness(struct btf *btf, enum btf_endianness endian); +LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id); +LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id); +LIBBPF_API int btf__align_of(const struct btf *btf, __u32 id); +LIBBPF_API int btf__fd(const struct btf *btf); +LIBBPF_API void btf__set_fd(struct btf *btf, int fd); +LIBBPF_API const void *btf__get_raw_data(const struct btf *btf, __u32 *size); +LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset); +LIBBPF_API const char *btf__str_by_offset(const struct btf *btf, __u32 offset); +LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf); +LIBBPF_API int btf__get_map_kv_tids(const struct btf *btf, const char *map_name, + __u32 expected_key_size, + __u32 expected_value_size, + __u32 *key_type_id, __u32 *value_type_id); + +LIBBPF_API struct btf_ext *btf_ext__new(__u8 *data, __u32 size); +LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext); +LIBBPF_API const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, + __u32 *size); +LIBBPF_API LIBBPF_DEPRECATED("btf_ext__reloc_func_info was never meant as a public API and has wrong assumptions embedded in it; it will be removed in the future libbpf versions") +int btf_ext__reloc_func_info(const struct btf *btf, + const struct btf_ext *btf_ext, + const char *sec_name, __u32 insns_cnt, + void **func_info, __u32 *cnt); +LIBBPF_API LIBBPF_DEPRECATED("btf_ext__reloc_line_info was never meant as a public API and has wrong assumptions embedded in it; it will be removed in the future libbpf versions") +int btf_ext__reloc_line_info(const struct btf *btf, + const struct btf_ext *btf_ext, + const char *sec_name, __u32 insns_cnt, + void **line_info, __u32 *cnt); +LIBBPF_API __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext); +LIBBPF_API __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext); + +LIBBPF_API struct btf *libbpf_find_kernel_btf(void); + +LIBBPF_API int btf__find_str(struct btf *btf, const char *s); +LIBBPF_API int btf__add_str(struct btf *btf, const char *s); + +LIBBPF_API int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding); +LIBBPF_API int btf__add_ptr(struct btf *btf, int ref_type_id); +LIBBPF_API int btf__add_array(struct btf *btf, + int index_type_id, int elem_type_id, __u32 nr_elems); +/* struct/union construction APIs */ +LIBBPF_API int btf__add_struct(struct btf *btf, const char *name, __u32 sz); +LIBBPF_API int btf__add_union(struct btf *btf, const char *name, __u32 sz); +LIBBPF_API int btf__add_field(struct btf *btf, const char *name, int field_type_id, + __u32 bit_offset, __u32 bit_size); + +/* enum construction APIs */ +LIBBPF_API int btf__add_enum(struct btf *btf, const char *name, __u32 bytes_sz); +LIBBPF_API int btf__add_enum_value(struct btf *btf, const char *name, __s64 value); + +enum btf_fwd_kind { + BTF_FWD_STRUCT = 0, + BTF_FWD_UNION = 1, + BTF_FWD_ENUM = 2, +}; + +LIBBPF_API int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind); +LIBBPF_API int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id); +LIBBPF_API int btf__add_volatile(struct btf *btf, int ref_type_id); +LIBBPF_API int btf__add_const(struct btf *btf, int ref_type_id); +LIBBPF_API int btf__add_restrict(struct btf *btf, int ref_type_id); + +/* func and func_proto construction APIs */ +LIBBPF_API int btf__add_func(struct btf *btf, const char *name, + enum btf_func_linkage linkage, int proto_type_id); +LIBBPF_API int btf__add_func_proto(struct btf *btf, int ret_type_id); +LIBBPF_API int btf__add_func_param(struct btf *btf, const char *name, int type_id); + +/* var & datasec construction APIs */ +LIBBPF_API int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id); +LIBBPF_API int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz); +LIBBPF_API int btf__add_datasec_var_info(struct btf *btf, int var_type_id, + __u32 offset, __u32 byte_sz); + +struct btf_dedup_opts { + unsigned int dedup_table_size; + bool dont_resolve_fwds; +}; + +LIBBPF_API int btf__dedup(struct btf *btf, struct btf_ext *btf_ext, + const struct btf_dedup_opts *opts); + +struct btf_dump; + +struct btf_dump_opts { + void *ctx; +}; + +typedef void (*btf_dump_printf_fn_t)(void *ctx, const char *fmt, va_list args); + +LIBBPF_API struct btf_dump *btf_dump__new(const struct btf *btf, + const struct btf_ext *btf_ext, + const struct btf_dump_opts *opts, + btf_dump_printf_fn_t printf_fn); +LIBBPF_API void btf_dump__free(struct btf_dump *d); + +LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id); + +struct btf_dump_emit_type_decl_opts { + /* size of this struct, for forward/backward compatiblity */ + size_t sz; + /* optional field name for type declaration, e.g.: + * - struct my_struct <FNAME> + * - void (*<FNAME>)(int) + * - char (*<FNAME>)[123] + */ + const char *field_name; + /* extra indentation level (in number of tabs) to emit for multi-line + * type declarations (e.g., anonymous struct); applies for lines + * starting from the second one (first line is assumed to have + * necessary indentation already + */ + int indent_level; + /* strip all the const/volatile/restrict mods */ + bool strip_mods; + size_t :0; +}; +#define btf_dump_emit_type_decl_opts__last_field strip_mods + +LIBBPF_API int +btf_dump__emit_type_decl(struct btf_dump *d, __u32 id, + const struct btf_dump_emit_type_decl_opts *opts); + +/* + * A set of helpers for easier BTF types handling + */ +static inline __u16 btf_kind(const struct btf_type *t) +{ + return BTF_INFO_KIND(t->info); +} + +static inline __u16 btf_vlen(const struct btf_type *t) +{ + return BTF_INFO_VLEN(t->info); +} + +static inline bool btf_kflag(const struct btf_type *t) +{ + return BTF_INFO_KFLAG(t->info); +} + +static inline bool btf_is_void(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_UNKN; +} + +static inline bool btf_is_int(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_INT; +} + +static inline bool btf_is_ptr(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_PTR; +} + +static inline bool btf_is_array(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_ARRAY; +} + +static inline bool btf_is_struct(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_STRUCT; +} + +static inline bool btf_is_union(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_UNION; +} + +static inline bool btf_is_composite(const struct btf_type *t) +{ + __u16 kind = btf_kind(t); + + return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION; +} + +static inline bool btf_is_enum(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_ENUM; +} + +static inline bool btf_is_fwd(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_FWD; +} + +static inline bool btf_is_typedef(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_TYPEDEF; +} + +static inline bool btf_is_volatile(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_VOLATILE; +} + +static inline bool btf_is_const(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_CONST; +} + +static inline bool btf_is_restrict(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_RESTRICT; +} + +static inline bool btf_is_mod(const struct btf_type *t) +{ + __u16 kind = btf_kind(t); + + return kind == BTF_KIND_VOLATILE || + kind == BTF_KIND_CONST || + kind == BTF_KIND_RESTRICT; +} + +static inline bool btf_is_func(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_FUNC; +} + +static inline bool btf_is_func_proto(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_FUNC_PROTO; +} + +static inline bool btf_is_var(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_VAR; +} + +static inline bool btf_is_datasec(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_DATASEC; +} + +static inline __u8 btf_int_encoding(const struct btf_type *t) +{ + return BTF_INT_ENCODING(*(__u32 *)(t + 1)); +} + +static inline __u8 btf_int_offset(const struct btf_type *t) +{ + return BTF_INT_OFFSET(*(__u32 *)(t + 1)); +} + +static inline __u8 btf_int_bits(const struct btf_type *t) +{ + return BTF_INT_BITS(*(__u32 *)(t + 1)); +} + +static inline struct btf_array *btf_array(const struct btf_type *t) +{ + return (struct btf_array *)(t + 1); +} + +static inline struct btf_enum *btf_enum(const struct btf_type *t) +{ + return (struct btf_enum *)(t + 1); +} + +static inline struct btf_member *btf_members(const struct btf_type *t) +{ + return (struct btf_member *)(t + 1); +} + +/* Get bit offset of a member with specified index. */ +static inline __u32 btf_member_bit_offset(const struct btf_type *t, + __u32 member_idx) +{ + const struct btf_member *m = btf_members(t) + member_idx; + bool kflag = btf_kflag(t); + + return kflag ? BTF_MEMBER_BIT_OFFSET(m->offset) : m->offset; +} +/* + * Get bitfield size of a member, assuming t is BTF_KIND_STRUCT or + * BTF_KIND_UNION. If member is not a bitfield, zero is returned. + */ +static inline __u32 btf_member_bitfield_size(const struct btf_type *t, + __u32 member_idx) +{ + const struct btf_member *m = btf_members(t) + member_idx; + bool kflag = btf_kflag(t); + + return kflag ? BTF_MEMBER_BITFIELD_SIZE(m->offset) : 0; +} + +static inline struct btf_param *btf_params(const struct btf_type *t) +{ + return (struct btf_param *)(t + 1); +} + +static inline struct btf_var *btf_var(const struct btf_type *t) +{ + return (struct btf_var *)(t + 1); +} + +static inline struct btf_var_secinfo * +btf_var_secinfos(const struct btf_type *t) +{ + return (struct btf_var_secinfo *)(t + 1); +} + +#ifdef __cplusplus +} /* extern "C" */ +#endif + +#endif /* __LIBBPF_BTF_H */ diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c new file mode 100644 index 000000000..61aa2c47f --- /dev/null +++ b/tools/lib/bpf/btf_dump.c @@ -0,0 +1,1531 @@ +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) + +/* + * BTF-to-C type converter. + * + * Copyright (c) 2019 Facebook + */ + +#include <stdbool.h> +#include <stddef.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <linux/err.h> +#include <linux/btf.h> +#include <linux/kernel.h> +#include "btf.h" +#include "hashmap.h" +#include "libbpf.h" +#include "libbpf_internal.h" + +static const char PREFIXES[] = "\t\t\t\t\t\t\t\t\t\t\t\t\t"; +static const size_t PREFIX_CNT = sizeof(PREFIXES) - 1; + +static const char *pfx(int lvl) +{ + return lvl >= PREFIX_CNT ? PREFIXES : &PREFIXES[PREFIX_CNT - lvl]; +} + +enum btf_dump_type_order_state { + NOT_ORDERED, + ORDERING, + ORDERED, +}; + +enum btf_dump_type_emit_state { + NOT_EMITTED, + EMITTING, + EMITTED, +}; + +/* per-type auxiliary state */ +struct btf_dump_type_aux_state { + /* topological sorting state */ + enum btf_dump_type_order_state order_state: 2; + /* emitting state used to determine the need for forward declaration */ + enum btf_dump_type_emit_state emit_state: 2; + /* whether forward declaration was already emitted */ + __u8 fwd_emitted: 1; + /* whether unique non-duplicate name was already assigned */ + __u8 name_resolved: 1; + /* whether type is referenced from any other type */ + __u8 referenced: 1; +}; + +struct btf_dump { + const struct btf *btf; + const struct btf_ext *btf_ext; + btf_dump_printf_fn_t printf_fn; + struct btf_dump_opts opts; + int ptr_sz; + bool strip_mods; + int last_id; + + /* per-type auxiliary state */ + struct btf_dump_type_aux_state *type_states; + size_t type_states_cap; + /* per-type optional cached unique name, must be freed, if present */ + const char **cached_names; + size_t cached_names_cap; + + /* topo-sorted list of dependent type definitions */ + __u32 *emit_queue; + int emit_queue_cap; + int emit_queue_cnt; + + /* + * stack of type declarations (e.g., chain of modifiers, arrays, + * funcs, etc) + */ + __u32 *decl_stack; + int decl_stack_cap; + int decl_stack_cnt; + + /* maps struct/union/enum name to a number of name occurrences */ + struct hashmap *type_names; + /* + * maps typedef identifiers and enum value names to a number of such + * name occurrences + */ + struct hashmap *ident_names; +}; + +static size_t str_hash_fn(const void *key, void *ctx) +{ + return str_hash(key); +} + +static bool str_equal_fn(const void *a, const void *b, void *ctx) +{ + return strcmp(a, b) == 0; +} + +static const char *btf_name_of(const struct btf_dump *d, __u32 name_off) +{ + return btf__name_by_offset(d->btf, name_off); +} + +static void btf_dump_printf(const struct btf_dump *d, const char *fmt, ...) +{ + va_list args; + + va_start(args, fmt); + d->printf_fn(d->opts.ctx, fmt, args); + va_end(args); +} + +static int btf_dump_mark_referenced(struct btf_dump *d); +static int btf_dump_resize(struct btf_dump *d); + +struct btf_dump *btf_dump__new(const struct btf *btf, + const struct btf_ext *btf_ext, + const struct btf_dump_opts *opts, + btf_dump_printf_fn_t printf_fn) +{ + struct btf_dump *d; + int err; + + d = calloc(1, sizeof(struct btf_dump)); + if (!d) + return ERR_PTR(-ENOMEM); + + d->btf = btf; + d->btf_ext = btf_ext; + d->printf_fn = printf_fn; + d->opts.ctx = opts ? opts->ctx : NULL; + d->ptr_sz = btf__pointer_size(btf) ? : sizeof(void *); + + d->type_names = hashmap__new(str_hash_fn, str_equal_fn, NULL); + if (IS_ERR(d->type_names)) { + err = PTR_ERR(d->type_names); + d->type_names = NULL; + goto err; + } + d->ident_names = hashmap__new(str_hash_fn, str_equal_fn, NULL); + if (IS_ERR(d->ident_names)) { + err = PTR_ERR(d->ident_names); + d->ident_names = NULL; + goto err; + } + + err = btf_dump_resize(d); + if (err) + goto err; + + return d; +err: + btf_dump__free(d); + return ERR_PTR(err); +} + +static int btf_dump_resize(struct btf_dump *d) +{ + int err, last_id = btf__get_nr_types(d->btf); + + if (last_id <= d->last_id) + return 0; + + if (btf_ensure_mem((void **)&d->type_states, &d->type_states_cap, + sizeof(*d->type_states), last_id + 1)) + return -ENOMEM; + if (btf_ensure_mem((void **)&d->cached_names, &d->cached_names_cap, + sizeof(*d->cached_names), last_id + 1)) + return -ENOMEM; + + if (d->last_id == 0) { + /* VOID is special */ + d->type_states[0].order_state = ORDERED; + d->type_states[0].emit_state = EMITTED; + } + + /* eagerly determine referenced types for anon enums */ + err = btf_dump_mark_referenced(d); + if (err) + return err; + + d->last_id = last_id; + return 0; +} + +static void btf_dump_free_names(struct hashmap *map) +{ + size_t bkt; + struct hashmap_entry *cur; + + hashmap__for_each_entry(map, cur, bkt) + free((void *)cur->key); + + hashmap__free(map); +} + +void btf_dump__free(struct btf_dump *d) +{ + int i; + + if (IS_ERR_OR_NULL(d)) + return; + + free(d->type_states); + if (d->cached_names) { + /* any set cached name is owned by us and should be freed */ + for (i = 0; i <= d->last_id; i++) { + if (d->cached_names[i]) + free((void *)d->cached_names[i]); + } + } + free(d->cached_names); + free(d->emit_queue); + free(d->decl_stack); + btf_dump_free_names(d->type_names); + btf_dump_free_names(d->ident_names); + + free(d); +} + +static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr); +static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id); + +/* + * Dump BTF type in a compilable C syntax, including all the necessary + * dependent types, necessary for compilation. If some of the dependent types + * were already emitted as part of previous btf_dump__dump_type() invocation + * for another type, they won't be emitted again. This API allows callers to + * filter out BTF types according to user-defined criterias and emitted only + * minimal subset of types, necessary to compile everything. Full struct/union + * definitions will still be emitted, even if the only usage is through + * pointer and could be satisfied with just a forward declaration. + * + * Dumping is done in two high-level passes: + * 1. Topologically sort type definitions to satisfy C rules of compilation. + * 2. Emit type definitions in C syntax. + * + * Returns 0 on success; <0, otherwise. + */ +int btf_dump__dump_type(struct btf_dump *d, __u32 id) +{ + int err, i; + + if (id > btf__get_nr_types(d->btf)) + return -EINVAL; + + err = btf_dump_resize(d); + if (err) + return err; + + d->emit_queue_cnt = 0; + err = btf_dump_order_type(d, id, false); + if (err < 0) + return err; + + for (i = 0; i < d->emit_queue_cnt; i++) + btf_dump_emit_type(d, d->emit_queue[i], 0 /*top-level*/); + + return 0; +} + +/* + * Mark all types that are referenced from any other type. This is used to + * determine top-level anonymous enums that need to be emitted as an + * independent type declarations. + * Anonymous enums come in two flavors: either embedded in a struct's field + * definition, in which case they have to be declared inline as part of field + * type declaration; or as a top-level anonymous enum, typically used for + * declaring global constants. It's impossible to distinguish between two + * without knowning whether given enum type was referenced from other type: + * top-level anonymous enum won't be referenced by anything, while embedded + * one will. + */ +static int btf_dump_mark_referenced(struct btf_dump *d) +{ + int i, j, n = btf__get_nr_types(d->btf); + const struct btf_type *t; + __u16 vlen; + + for (i = d->last_id + 1; i <= n; i++) { + t = btf__type_by_id(d->btf, i); + vlen = btf_vlen(t); + + switch (btf_kind(t)) { + case BTF_KIND_INT: + case BTF_KIND_ENUM: + case BTF_KIND_FWD: + break; + + case BTF_KIND_VOLATILE: + case BTF_KIND_CONST: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + case BTF_KIND_VAR: + d->type_states[t->type].referenced = 1; + break; + + case BTF_KIND_ARRAY: { + const struct btf_array *a = btf_array(t); + + d->type_states[a->index_type].referenced = 1; + d->type_states[a->type].referenced = 1; + break; + } + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: { + const struct btf_member *m = btf_members(t); + + for (j = 0; j < vlen; j++, m++) + d->type_states[m->type].referenced = 1; + break; + } + case BTF_KIND_FUNC_PROTO: { + const struct btf_param *p = btf_params(t); + + for (j = 0; j < vlen; j++, p++) + d->type_states[p->type].referenced = 1; + break; + } + case BTF_KIND_DATASEC: { + const struct btf_var_secinfo *v = btf_var_secinfos(t); + + for (j = 0; j < vlen; j++, v++) + d->type_states[v->type].referenced = 1; + break; + } + default: + return -EINVAL; + } + } + return 0; +} + +static int btf_dump_add_emit_queue_id(struct btf_dump *d, __u32 id) +{ + __u32 *new_queue; + size_t new_cap; + + if (d->emit_queue_cnt >= d->emit_queue_cap) { + new_cap = max(16, d->emit_queue_cap * 3 / 2); + new_queue = libbpf_reallocarray(d->emit_queue, new_cap, sizeof(new_queue[0])); + if (!new_queue) + return -ENOMEM; + d->emit_queue = new_queue; + d->emit_queue_cap = new_cap; + } + + d->emit_queue[d->emit_queue_cnt++] = id; + return 0; +} + +/* + * Determine order of emitting dependent types and specified type to satisfy + * C compilation rules. This is done through topological sorting with an + * additional complication which comes from C rules. The main idea for C is + * that if some type is "embedded" into a struct/union, it's size needs to be + * known at the time of definition of containing type. E.g., for: + * + * struct A {}; + * struct B { struct A x; } + * + * struct A *HAS* to be defined before struct B, because it's "embedded", + * i.e., it is part of struct B layout. But in the following case: + * + * struct A; + * struct B { struct A *x; } + * struct A {}; + * + * it's enough to just have a forward declaration of struct A at the time of + * struct B definition, as struct B has a pointer to struct A, so the size of + * field x is known without knowing struct A size: it's sizeof(void *). + * + * Unfortunately, there are some trickier cases we need to handle, e.g.: + * + * struct A {}; // if this was forward-declaration: compilation error + * struct B { + * struct { // anonymous struct + * struct A y; + * } *x; + * }; + * + * In this case, struct B's field x is a pointer, so it's size is known + * regardless of the size of (anonymous) struct it points to. But because this + * struct is anonymous and thus defined inline inside struct B, *and* it + * embeds struct A, compiler requires full definition of struct A to be known + * before struct B can be defined. This creates a transitive dependency + * between struct A and struct B. If struct A was forward-declared before + * struct B definition and fully defined after struct B definition, that would + * trigger compilation error. + * + * All this means that while we are doing topological sorting on BTF type + * graph, we need to determine relationships between different types (graph + * nodes): + * - weak link (relationship) between X and Y, if Y *CAN* be + * forward-declared at the point of X definition; + * - strong link, if Y *HAS* to be fully-defined before X can be defined. + * + * The rule is as follows. Given a chain of BTF types from X to Y, if there is + * BTF_KIND_PTR type in the chain and at least one non-anonymous type + * Z (excluding X, including Y), then link is weak. Otherwise, it's strong. + * Weak/strong relationship is determined recursively during DFS traversal and + * is returned as a result from btf_dump_order_type(). + * + * btf_dump_order_type() is trying to avoid unnecessary forward declarations, + * but it is not guaranteeing that no extraneous forward declarations will be + * emitted. + * + * To avoid extra work, algorithm marks some of BTF types as ORDERED, when + * it's done with them, but not for all (e.g., VOLATILE, CONST, RESTRICT, + * ARRAY, FUNC_PROTO), as weak/strong semantics for those depends on the + * entire graph path, so depending where from one came to that BTF type, it + * might cause weak or strong ordering. For types like STRUCT/UNION/INT/ENUM, + * once they are processed, there is no need to do it again, so they are + * marked as ORDERED. We can mark PTR as ORDERED as well, as it semi-forces + * weak link, unless subsequent referenced STRUCT/UNION/ENUM is anonymous. But + * in any case, once those are processed, no need to do it again, as the + * result won't change. + * + * Returns: + * - 1, if type is part of strong link (so there is strong topological + * ordering requirements); + * - 0, if type is part of weak link (so can be satisfied through forward + * declaration); + * - <0, on error (e.g., unsatisfiable type loop detected). + */ +static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr) +{ + /* + * Order state is used to detect strong link cycles, but only for BTF + * kinds that are or could be an independent definition (i.e., + * stand-alone fwd decl, enum, typedef, struct, union). Ptrs, arrays, + * func_protos, modifiers are just means to get to these definitions. + * Int/void don't need definitions, they are assumed to be always + * properly defined. We also ignore datasec, var, and funcs for now. + * So for all non-defining kinds, we never even set ordering state, + * for defining kinds we set ORDERING and subsequently ORDERED if it + * forms a strong link. + */ + struct btf_dump_type_aux_state *tstate = &d->type_states[id]; + const struct btf_type *t; + __u16 vlen; + int err, i; + + /* return true, letting typedefs know that it's ok to be emitted */ + if (tstate->order_state == ORDERED) + return 1; + + t = btf__type_by_id(d->btf, id); + + if (tstate->order_state == ORDERING) { + /* type loop, but resolvable through fwd declaration */ + if (btf_is_composite(t) && through_ptr && t->name_off != 0) + return 0; + pr_warn("unsatisfiable type cycle, id:[%u]\n", id); + return -ELOOP; + } + + switch (btf_kind(t)) { + case BTF_KIND_INT: + tstate->order_state = ORDERED; + return 0; + + case BTF_KIND_PTR: + err = btf_dump_order_type(d, t->type, true); + tstate->order_state = ORDERED; + return err; + + case BTF_KIND_ARRAY: + return btf_dump_order_type(d, btf_array(t)->type, false); + + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: { + const struct btf_member *m = btf_members(t); + /* + * struct/union is part of strong link, only if it's embedded + * (so no ptr in a path) or it's anonymous (so has to be + * defined inline, even if declared through ptr) + */ + if (through_ptr && t->name_off != 0) + return 0; + + tstate->order_state = ORDERING; + + vlen = btf_vlen(t); + for (i = 0; i < vlen; i++, m++) { + err = btf_dump_order_type(d, m->type, false); + if (err < 0) + return err; + } + + if (t->name_off != 0) { + err = btf_dump_add_emit_queue_id(d, id); + if (err < 0) + return err; + } + + tstate->order_state = ORDERED; + return 1; + } + case BTF_KIND_ENUM: + case BTF_KIND_FWD: + /* + * non-anonymous or non-referenced enums are top-level + * declarations and should be emitted. Same logic can be + * applied to FWDs, it won't hurt anyways. + */ + if (t->name_off != 0 || !tstate->referenced) { + err = btf_dump_add_emit_queue_id(d, id); + if (err) + return err; + } + tstate->order_state = ORDERED; + return 1; + + case BTF_KIND_TYPEDEF: { + int is_strong; + + is_strong = btf_dump_order_type(d, t->type, through_ptr); + if (is_strong < 0) + return is_strong; + + /* typedef is similar to struct/union w.r.t. fwd-decls */ + if (through_ptr && !is_strong) + return 0; + + /* typedef is always a named definition */ + err = btf_dump_add_emit_queue_id(d, id); + if (err) + return err; + + d->type_states[id].order_state = ORDERED; + return 1; + } + case BTF_KIND_VOLATILE: + case BTF_KIND_CONST: + case BTF_KIND_RESTRICT: + return btf_dump_order_type(d, t->type, through_ptr); + + case BTF_KIND_FUNC_PROTO: { + const struct btf_param *p = btf_params(t); + bool is_strong; + + err = btf_dump_order_type(d, t->type, through_ptr); + if (err < 0) + return err; + is_strong = err > 0; + + vlen = btf_vlen(t); + for (i = 0; i < vlen; i++, p++) { + err = btf_dump_order_type(d, p->type, through_ptr); + if (err < 0) + return err; + if (err > 0) + is_strong = true; + } + return is_strong; + } + case BTF_KIND_FUNC: + case BTF_KIND_VAR: + case BTF_KIND_DATASEC: + d->type_states[id].order_state = ORDERED; + return 0; + + default: + return -EINVAL; + } +} + +static void btf_dump_emit_missing_aliases(struct btf_dump *d, __u32 id, + const struct btf_type *t); + +static void btf_dump_emit_struct_fwd(struct btf_dump *d, __u32 id, + const struct btf_type *t); +static void btf_dump_emit_struct_def(struct btf_dump *d, __u32 id, + const struct btf_type *t, int lvl); + +static void btf_dump_emit_enum_fwd(struct btf_dump *d, __u32 id, + const struct btf_type *t); +static void btf_dump_emit_enum_def(struct btf_dump *d, __u32 id, + const struct btf_type *t, int lvl); + +static void btf_dump_emit_fwd_def(struct btf_dump *d, __u32 id, + const struct btf_type *t); + +static void btf_dump_emit_typedef_def(struct btf_dump *d, __u32 id, + const struct btf_type *t, int lvl); + +/* a local view into a shared stack */ +struct id_stack { + const __u32 *ids; + int cnt; +}; + +static void btf_dump_emit_type_decl(struct btf_dump *d, __u32 id, + const char *fname, int lvl); +static void btf_dump_emit_type_chain(struct btf_dump *d, + struct id_stack *decl_stack, + const char *fname, int lvl); + +static const char *btf_dump_type_name(struct btf_dump *d, __u32 id); +static const char *btf_dump_ident_name(struct btf_dump *d, __u32 id); +static size_t btf_dump_name_dups(struct btf_dump *d, struct hashmap *name_map, + const char *orig_name); + +static bool btf_dump_is_blacklisted(struct btf_dump *d, __u32 id) +{ + const struct btf_type *t = btf__type_by_id(d->btf, id); + + /* __builtin_va_list is a compiler built-in, which causes compilation + * errors, when compiling w/ different compiler, then used to compile + * original code (e.g., GCC to compile kernel, Clang to use generated + * C header from BTF). As it is built-in, it should be already defined + * properly internally in compiler. + */ + if (t->name_off == 0) + return false; + return strcmp(btf_name_of(d, t->name_off), "__builtin_va_list") == 0; +} + +/* + * Emit C-syntax definitions of types from chains of BTF types. + * + * High-level handling of determining necessary forward declarations are handled + * by btf_dump_emit_type() itself, but all nitty-gritty details of emitting type + * declarations/definitions in C syntax are handled by a combo of + * btf_dump_emit_type_decl()/btf_dump_emit_type_chain() w/ delegation to + * corresponding btf_dump_emit_*_{def,fwd}() functions. + * + * We also keep track of "containing struct/union type ID" to determine when + * we reference it from inside and thus can avoid emitting unnecessary forward + * declaration. + * + * This algorithm is designed in such a way, that even if some error occurs + * (either technical, e.g., out of memory, or logical, i.e., malformed BTF + * that doesn't comply to C rules completely), algorithm will try to proceed + * and produce as much meaningful output as possible. + */ +static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id) +{ + struct btf_dump_type_aux_state *tstate = &d->type_states[id]; + bool top_level_def = cont_id == 0; + const struct btf_type *t; + __u16 kind; + + if (tstate->emit_state == EMITTED) + return; + + t = btf__type_by_id(d->btf, id); + kind = btf_kind(t); + + if (tstate->emit_state == EMITTING) { + if (tstate->fwd_emitted) + return; + + switch (kind) { + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + /* + * if we are referencing a struct/union that we are + * part of - then no need for fwd declaration + */ + if (id == cont_id) + return; + if (t->name_off == 0) { + pr_warn("anonymous struct/union loop, id:[%u]\n", + id); + return; + } + btf_dump_emit_struct_fwd(d, id, t); + btf_dump_printf(d, ";\n\n"); + tstate->fwd_emitted = 1; + break; + case BTF_KIND_TYPEDEF: + /* + * for typedef fwd_emitted means typedef definition + * was emitted, but it can be used only for "weak" + * references through pointer only, not for embedding + */ + if (!btf_dump_is_blacklisted(d, id)) { + btf_dump_emit_typedef_def(d, id, t, 0); + btf_dump_printf(d, ";\n\n"); + } + tstate->fwd_emitted = 1; + break; + default: + break; + } + + return; + } + + switch (kind) { + case BTF_KIND_INT: + /* Emit type alias definitions if necessary */ + btf_dump_emit_missing_aliases(d, id, t); + + tstate->emit_state = EMITTED; + break; + case BTF_KIND_ENUM: + if (top_level_def) { + btf_dump_emit_enum_def(d, id, t, 0); + btf_dump_printf(d, ";\n\n"); + } + tstate->emit_state = EMITTED; + break; + case BTF_KIND_PTR: + case BTF_KIND_VOLATILE: + case BTF_KIND_CONST: + case BTF_KIND_RESTRICT: + btf_dump_emit_type(d, t->type, cont_id); + break; + case BTF_KIND_ARRAY: + btf_dump_emit_type(d, btf_array(t)->type, cont_id); + break; + case BTF_KIND_FWD: + btf_dump_emit_fwd_def(d, id, t); + btf_dump_printf(d, ";\n\n"); + tstate->emit_state = EMITTED; + break; + case BTF_KIND_TYPEDEF: + tstate->emit_state = EMITTING; + btf_dump_emit_type(d, t->type, id); + /* + * typedef can server as both definition and forward + * declaration; at this stage someone depends on + * typedef as a forward declaration (refers to it + * through pointer), so unless we already did it, + * emit typedef as a forward declaration + */ + if (!tstate->fwd_emitted && !btf_dump_is_blacklisted(d, id)) { + btf_dump_emit_typedef_def(d, id, t, 0); + btf_dump_printf(d, ";\n\n"); + } + tstate->emit_state = EMITTED; + break; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + tstate->emit_state = EMITTING; + /* if it's a top-level struct/union definition or struct/union + * is anonymous, then in C we'll be emitting all fields and + * their types (as opposed to just `struct X`), so we need to + * make sure that all types, referenced from struct/union + * members have necessary forward-declarations, where + * applicable + */ + if (top_level_def || t->name_off == 0) { + const struct btf_member *m = btf_members(t); + __u16 vlen = btf_vlen(t); + int i, new_cont_id; + + new_cont_id = t->name_off == 0 ? cont_id : id; + for (i = 0; i < vlen; i++, m++) + btf_dump_emit_type(d, m->type, new_cont_id); + } else if (!tstate->fwd_emitted && id != cont_id) { + btf_dump_emit_struct_fwd(d, id, t); + btf_dump_printf(d, ";\n\n"); + tstate->fwd_emitted = 1; + } + + if (top_level_def) { + btf_dump_emit_struct_def(d, id, t, 0); + btf_dump_printf(d, ";\n\n"); + tstate->emit_state = EMITTED; + } else { + tstate->emit_state = NOT_EMITTED; + } + break; + case BTF_KIND_FUNC_PROTO: { + const struct btf_param *p = btf_params(t); + __u16 vlen = btf_vlen(t); + int i; + + btf_dump_emit_type(d, t->type, cont_id); + for (i = 0; i < vlen; i++, p++) + btf_dump_emit_type(d, p->type, cont_id); + + break; + } + default: + break; + } +} + +static bool btf_is_struct_packed(const struct btf *btf, __u32 id, + const struct btf_type *t) +{ + const struct btf_member *m; + int max_align = 1, align, i, bit_sz; + __u16 vlen; + + m = btf_members(t); + vlen = btf_vlen(t); + /* all non-bitfield fields have to be naturally aligned */ + for (i = 0; i < vlen; i++, m++) { + align = btf__align_of(btf, m->type); + bit_sz = btf_member_bitfield_size(t, i); + if (align && bit_sz == 0 && m->offset % (8 * align) != 0) + return true; + max_align = max(align, max_align); + } + /* size of a non-packed struct has to be a multiple of its alignment */ + if (t->size % max_align != 0) + return true; + /* + * if original struct was marked as packed, but its layout is + * naturally aligned, we'll detect that it's not packed + */ + return false; +} + +static void btf_dump_emit_bit_padding(const struct btf_dump *d, + int cur_off, int next_off, int next_align, + bool in_bitfield, int lvl) +{ + const struct { + const char *name; + int bits; + } pads[] = { + {"long", d->ptr_sz * 8}, {"int", 32}, {"short", 16}, {"char", 8} + }; + int new_off, pad_bits, bits, i; + const char *pad_type; + + if (cur_off >= next_off) + return; /* no gap */ + + /* For filling out padding we want to take advantage of + * natural alignment rules to minimize unnecessary explicit + * padding. First, we find the largest type (among long, int, + * short, or char) that can be used to force naturally aligned + * boundary. Once determined, we'll use such type to fill in + * the remaining padding gap. In some cases we can rely on + * compiler filling some gaps, but sometimes we need to force + * alignment to close natural alignment with markers like + * `long: 0` (this is always the case for bitfields). Note + * that even if struct itself has, let's say 4-byte alignment + * (i.e., it only uses up to int-aligned types), using `long: + * X;` explicit padding doesn't actually change struct's + * overall alignment requirements, but compiler does take into + * account that type's (long, in this example) natural + * alignment requirements when adding implicit padding. We use + * this fact heavily and don't worry about ruining correct + * struct alignment requirement. + */ + for (i = 0; i < ARRAY_SIZE(pads); i++) { + pad_bits = pads[i].bits; + pad_type = pads[i].name; + + new_off = roundup(cur_off, pad_bits); + if (new_off <= next_off) + break; + } + + if (new_off > cur_off && new_off <= next_off) { + /* We need explicit `<type>: 0` aligning mark if next + * field is right on alignment offset and its + * alignment requirement is less strict than <type>'s + * alignment (so compiler won't naturally align to the + * offset we expect), or if subsequent `<type>: X`, + * will actually completely fit in the remaining hole, + * making compiler basically ignore `<type>: X` + * completely. + */ + if (in_bitfield || + (new_off == next_off && roundup(cur_off, next_align * 8) != new_off) || + (new_off != next_off && next_off - new_off <= new_off - cur_off)) + /* but for bitfields we'll emit explicit bit count */ + btf_dump_printf(d, "\n%s%s: %d;", pfx(lvl), pad_type, + in_bitfield ? new_off - cur_off : 0); + cur_off = new_off; + } + + /* Now we know we start at naturally aligned offset for a chosen + * padding type (long, int, short, or char), and so the rest is just + * a straightforward filling of remaining padding gap with full + * `<type>: sizeof(<type>);` markers, except for the last one, which + * might need smaller than sizeof(<type>) padding. + */ + while (cur_off != next_off) { + bits = min(next_off - cur_off, pad_bits); + if (bits == pad_bits) { + btf_dump_printf(d, "\n%s%s: %d;", pfx(lvl), pad_type, pad_bits); + cur_off += bits; + continue; + } + /* For the remainder padding that doesn't cover entire + * pad_type bit length, we pick the smallest necessary type. + * This is pure aesthetics, we could have just used `long`, + * but having smallest necessary one communicates better the + * scale of the padding gap. + */ + for (i = ARRAY_SIZE(pads) - 1; i >= 0; i--) { + pad_type = pads[i].name; + pad_bits = pads[i].bits; + if (pad_bits < bits) + continue; + + btf_dump_printf(d, "\n%s%s: %d;", pfx(lvl), pad_type, bits); + cur_off += bits; + break; + } + } +} + +static void btf_dump_emit_struct_fwd(struct btf_dump *d, __u32 id, + const struct btf_type *t) +{ + btf_dump_printf(d, "%s %s", + btf_is_struct(t) ? "struct" : "union", + btf_dump_type_name(d, id)); +} + +static void btf_dump_emit_struct_def(struct btf_dump *d, + __u32 id, + const struct btf_type *t, + int lvl) +{ + const struct btf_member *m = btf_members(t); + bool is_struct = btf_is_struct(t); + bool packed, prev_bitfield = false; + int align, i, off = 0; + __u16 vlen = btf_vlen(t); + + align = btf__align_of(d->btf, id); + packed = is_struct ? btf_is_struct_packed(d->btf, id, t) : 0; + + btf_dump_printf(d, "%s%s%s {", + is_struct ? "struct" : "union", + t->name_off ? " " : "", + btf_dump_type_name(d, id)); + + for (i = 0; i < vlen; i++, m++) { + const char *fname; + int m_off, m_sz, m_align; + bool in_bitfield; + + fname = btf_name_of(d, m->name_off); + m_sz = btf_member_bitfield_size(t, i); + m_off = btf_member_bit_offset(t, i); + m_align = packed ? 1 : btf__align_of(d->btf, m->type); + + in_bitfield = prev_bitfield && m_sz != 0; + + btf_dump_emit_bit_padding(d, off, m_off, m_align, in_bitfield, lvl + 1); + btf_dump_printf(d, "\n%s", pfx(lvl + 1)); + btf_dump_emit_type_decl(d, m->type, fname, lvl + 1); + + if (m_sz) { + btf_dump_printf(d, ": %d", m_sz); + off = m_off + m_sz; + prev_bitfield = true; + } else { + m_sz = max((__s64)0, btf__resolve_size(d->btf, m->type)); + off = m_off + m_sz * 8; + prev_bitfield = false; + } + + btf_dump_printf(d, ";"); + } + + /* pad at the end, if necessary */ + if (is_struct) + btf_dump_emit_bit_padding(d, off, t->size * 8, align, false, lvl + 1); + + /* + * Keep `struct empty {}` on a single line, + * only print newline when there are regular or padding fields. + */ + if (vlen || t->size) { + btf_dump_printf(d, "\n"); + btf_dump_printf(d, "%s}", pfx(lvl)); + } else { + btf_dump_printf(d, "}"); + } + if (packed) + btf_dump_printf(d, " __attribute__((packed))"); +} + +static const char *missing_base_types[][2] = { + /* + * GCC emits typedefs to its internal __PolyX_t types when compiling Arm + * SIMD intrinsics. Alias them to standard base types. + */ + { "__Poly8_t", "unsigned char" }, + { "__Poly16_t", "unsigned short" }, + { "__Poly64_t", "unsigned long long" }, + { "__Poly128_t", "unsigned __int128" }, +}; + +static void btf_dump_emit_missing_aliases(struct btf_dump *d, __u32 id, + const struct btf_type *t) +{ + const char *name = btf_dump_type_name(d, id); + int i; + + for (i = 0; i < ARRAY_SIZE(missing_base_types); i++) { + if (strcmp(name, missing_base_types[i][0]) == 0) { + btf_dump_printf(d, "typedef %s %s;\n\n", + missing_base_types[i][1], name); + break; + } + } +} + +static void btf_dump_emit_enum_fwd(struct btf_dump *d, __u32 id, + const struct btf_type *t) +{ + btf_dump_printf(d, "enum %s", btf_dump_type_name(d, id)); +} + +static void btf_dump_emit_enum_def(struct btf_dump *d, __u32 id, + const struct btf_type *t, + int lvl) +{ + const struct btf_enum *v = btf_enum(t); + __u16 vlen = btf_vlen(t); + const char *name; + size_t dup_cnt; + int i; + + btf_dump_printf(d, "enum%s%s", + t->name_off ? " " : "", + btf_dump_type_name(d, id)); + + if (vlen) { + btf_dump_printf(d, " {"); + for (i = 0; i < vlen; i++, v++) { + name = btf_name_of(d, v->name_off); + /* enumerators share namespace with typedef idents */ + dup_cnt = btf_dump_name_dups(d, d->ident_names, name); + if (dup_cnt > 1) { + btf_dump_printf(d, "\n%s%s___%zu = %u,", + pfx(lvl + 1), name, dup_cnt, + (__u32)v->val); + } else { + btf_dump_printf(d, "\n%s%s = %u,", + pfx(lvl + 1), name, + (__u32)v->val); + } + } + btf_dump_printf(d, "\n%s}", pfx(lvl)); + } +} + +static void btf_dump_emit_fwd_def(struct btf_dump *d, __u32 id, + const struct btf_type *t) +{ + const char *name = btf_dump_type_name(d, id); + + if (btf_kflag(t)) + btf_dump_printf(d, "union %s", name); + else + btf_dump_printf(d, "struct %s", name); +} + +static void btf_dump_emit_typedef_def(struct btf_dump *d, __u32 id, + const struct btf_type *t, int lvl) +{ + const char *name = btf_dump_ident_name(d, id); + + /* + * Old GCC versions are emitting invalid typedef for __gnuc_va_list + * pointing to VOID. This generates warnings from btf_dump() and + * results in uncompilable header file, so we are fixing it up here + * with valid typedef into __builtin_va_list. + */ + if (t->type == 0 && strcmp(name, "__gnuc_va_list") == 0) { + btf_dump_printf(d, "typedef __builtin_va_list __gnuc_va_list"); + return; + } + + btf_dump_printf(d, "typedef "); + btf_dump_emit_type_decl(d, t->type, name, lvl); +} + +static int btf_dump_push_decl_stack_id(struct btf_dump *d, __u32 id) +{ + __u32 *new_stack; + size_t new_cap; + + if (d->decl_stack_cnt >= d->decl_stack_cap) { + new_cap = max(16, d->decl_stack_cap * 3 / 2); + new_stack = libbpf_reallocarray(d->decl_stack, new_cap, sizeof(new_stack[0])); + if (!new_stack) + return -ENOMEM; + d->decl_stack = new_stack; + d->decl_stack_cap = new_cap; + } + + d->decl_stack[d->decl_stack_cnt++] = id; + + return 0; +} + +/* + * Emit type declaration (e.g., field type declaration in a struct or argument + * declaration in function prototype) in correct C syntax. + * + * For most types it's trivial, but there are few quirky type declaration + * cases worth mentioning: + * - function prototypes (especially nesting of function prototypes); + * - arrays; + * - const/volatile/restrict for pointers vs other types. + * + * For a good discussion of *PARSING* C syntax (as a human), see + * Peter van der Linden's "Expert C Programming: Deep C Secrets", + * Ch.3 "Unscrambling Declarations in C". + * + * It won't help with BTF to C conversion much, though, as it's an opposite + * problem. So we came up with this algorithm in reverse to van der Linden's + * parsing algorithm. It goes from structured BTF representation of type + * declaration to a valid compilable C syntax. + * + * For instance, consider this C typedef: + * typedef const int * const * arr[10] arr_t; + * It will be represented in BTF with this chain of BTF types: + * [typedef] -> [array] -> [ptr] -> [const] -> [ptr] -> [const] -> [int] + * + * Notice how [const] modifier always goes before type it modifies in BTF type + * graph, but in C syntax, const/volatile/restrict modifiers are written to + * the right of pointers, but to the left of other types. There are also other + * quirks, like function pointers, arrays of them, functions returning other + * functions, etc. + * + * We handle that by pushing all the types to a stack, until we hit "terminal" + * type (int/enum/struct/union/fwd). Then depending on the kind of a type on + * top of a stack, modifiers are handled differently. Array/function pointers + * have also wildly different syntax and how nesting of them are done. See + * code for authoritative definition. + * + * To avoid allocating new stack for each independent chain of BTF types, we + * share one bigger stack, with each chain working only on its own local view + * of a stack frame. Some care is required to "pop" stack frames after + * processing type declaration chain. + */ +int btf_dump__emit_type_decl(struct btf_dump *d, __u32 id, + const struct btf_dump_emit_type_decl_opts *opts) +{ + const char *fname; + int lvl, err; + + if (!OPTS_VALID(opts, btf_dump_emit_type_decl_opts)) + return -EINVAL; + + err = btf_dump_resize(d); + if (err) + return -EINVAL; + + fname = OPTS_GET(opts, field_name, ""); + lvl = OPTS_GET(opts, indent_level, 0); + d->strip_mods = OPTS_GET(opts, strip_mods, false); + btf_dump_emit_type_decl(d, id, fname, lvl); + d->strip_mods = false; + return 0; +} + +static void btf_dump_emit_type_decl(struct btf_dump *d, __u32 id, + const char *fname, int lvl) +{ + struct id_stack decl_stack; + const struct btf_type *t; + int err, stack_start; + + stack_start = d->decl_stack_cnt; + for (;;) { + t = btf__type_by_id(d->btf, id); + if (d->strip_mods && btf_is_mod(t)) + goto skip_mod; + + err = btf_dump_push_decl_stack_id(d, id); + if (err < 0) { + /* + * if we don't have enough memory for entire type decl + * chain, restore stack, emit warning, and try to + * proceed nevertheless + */ + pr_warn("not enough memory for decl stack:%d", err); + d->decl_stack_cnt = stack_start; + return; + } +skip_mod: + /* VOID */ + if (id == 0) + break; + + switch (btf_kind(t)) { + case BTF_KIND_PTR: + case BTF_KIND_VOLATILE: + case BTF_KIND_CONST: + case BTF_KIND_RESTRICT: + case BTF_KIND_FUNC_PROTO: + id = t->type; + break; + case BTF_KIND_ARRAY: + id = btf_array(t)->type; + break; + case BTF_KIND_INT: + case BTF_KIND_ENUM: + case BTF_KIND_FWD: + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + case BTF_KIND_TYPEDEF: + goto done; + default: + pr_warn("unexpected type in decl chain, kind:%u, id:[%u]\n", + btf_kind(t), id); + goto done; + } + } +done: + /* + * We might be inside a chain of declarations (e.g., array of function + * pointers returning anonymous (so inlined) structs, having another + * array field). Each of those needs its own "stack frame" to handle + * emitting of declarations. Those stack frames are non-overlapping + * portions of shared btf_dump->decl_stack. To make it a bit nicer to + * handle this set of nested stacks, we create a view corresponding to + * our own "stack frame" and work with it as an independent stack. + * We'll need to clean up after emit_type_chain() returns, though. + */ + decl_stack.ids = d->decl_stack + stack_start; + decl_stack.cnt = d->decl_stack_cnt - stack_start; + btf_dump_emit_type_chain(d, &decl_stack, fname, lvl); + /* + * emit_type_chain() guarantees that it will pop its entire decl_stack + * frame before returning. But it works with a read-only view into + * decl_stack, so it doesn't actually pop anything from the + * perspective of shared btf_dump->decl_stack, per se. We need to + * reset decl_stack state to how it was before us to avoid it growing + * all the time. + */ + d->decl_stack_cnt = stack_start; +} + +static void btf_dump_emit_mods(struct btf_dump *d, struct id_stack *decl_stack) +{ + const struct btf_type *t; + __u32 id; + + while (decl_stack->cnt) { + id = decl_stack->ids[decl_stack->cnt - 1]; + t = btf__type_by_id(d->btf, id); + + switch (btf_kind(t)) { + case BTF_KIND_VOLATILE: + btf_dump_printf(d, "volatile "); + break; + case BTF_KIND_CONST: + btf_dump_printf(d, "const "); + break; + case BTF_KIND_RESTRICT: + btf_dump_printf(d, "restrict "); + break; + default: + return; + } + decl_stack->cnt--; + } +} + +static void btf_dump_drop_mods(struct btf_dump *d, struct id_stack *decl_stack) +{ + const struct btf_type *t; + __u32 id; + + while (decl_stack->cnt) { + id = decl_stack->ids[decl_stack->cnt - 1]; + t = btf__type_by_id(d->btf, id); + if (!btf_is_mod(t)) + return; + decl_stack->cnt--; + } +} + +static void btf_dump_emit_name(const struct btf_dump *d, + const char *name, bool last_was_ptr) +{ + bool separate = name[0] && !last_was_ptr; + + btf_dump_printf(d, "%s%s", separate ? " " : "", name); +} + +static void btf_dump_emit_type_chain(struct btf_dump *d, + struct id_stack *decls, + const char *fname, int lvl) +{ + /* + * last_was_ptr is used to determine if we need to separate pointer + * asterisk (*) from previous part of type signature with space, so + * that we get `int ***`, instead of `int * * *`. We default to true + * for cases where we have single pointer in a chain. E.g., in ptr -> + * func_proto case. func_proto will start a new emit_type_chain call + * with just ptr, which should be emitted as (*) or (*<fname>), so we + * don't want to prepend space for that last pointer. + */ + bool last_was_ptr = true; + const struct btf_type *t; + const char *name; + __u16 kind; + __u32 id; + + while (decls->cnt) { + id = decls->ids[--decls->cnt]; + if (id == 0) { + /* VOID is a special snowflake */ + btf_dump_emit_mods(d, decls); + btf_dump_printf(d, "void"); + last_was_ptr = false; + continue; + } + + t = btf__type_by_id(d->btf, id); + kind = btf_kind(t); + + switch (kind) { + case BTF_KIND_INT: + btf_dump_emit_mods(d, decls); + name = btf_name_of(d, t->name_off); + btf_dump_printf(d, "%s", name); + break; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + btf_dump_emit_mods(d, decls); + /* inline anonymous struct/union */ + if (t->name_off == 0) + btf_dump_emit_struct_def(d, id, t, lvl); + else + btf_dump_emit_struct_fwd(d, id, t); + break; + case BTF_KIND_ENUM: + btf_dump_emit_mods(d, decls); + /* inline anonymous enum */ + if (t->name_off == 0) + btf_dump_emit_enum_def(d, id, t, lvl); + else + btf_dump_emit_enum_fwd(d, id, t); + break; + case BTF_KIND_FWD: + btf_dump_emit_mods(d, decls); + btf_dump_emit_fwd_def(d, id, t); + break; + case BTF_KIND_TYPEDEF: + btf_dump_emit_mods(d, decls); + btf_dump_printf(d, "%s", btf_dump_ident_name(d, id)); + break; + case BTF_KIND_PTR: + btf_dump_printf(d, "%s", last_was_ptr ? "*" : " *"); + break; + case BTF_KIND_VOLATILE: + btf_dump_printf(d, " volatile"); + break; + case BTF_KIND_CONST: + btf_dump_printf(d, " const"); + break; + case BTF_KIND_RESTRICT: + btf_dump_printf(d, " restrict"); + break; + case BTF_KIND_ARRAY: { + const struct btf_array *a = btf_array(t); + const struct btf_type *next_t; + __u32 next_id; + bool multidim; + /* + * GCC has a bug + * (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=8354) + * which causes it to emit extra const/volatile + * modifiers for an array, if array's element type has + * const/volatile modifiers. Clang doesn't do that. + * In general, it doesn't seem very meaningful to have + * a const/volatile modifier for array, so we are + * going to silently skip them here. + */ + btf_dump_drop_mods(d, decls); + + if (decls->cnt == 0) { + btf_dump_emit_name(d, fname, last_was_ptr); + btf_dump_printf(d, "[%u]", a->nelems); + return; + } + + next_id = decls->ids[decls->cnt - 1]; + next_t = btf__type_by_id(d->btf, next_id); + multidim = btf_is_array(next_t); + /* we need space if we have named non-pointer */ + if (fname[0] && !last_was_ptr) + btf_dump_printf(d, " "); + /* no parentheses for multi-dimensional array */ + if (!multidim) + btf_dump_printf(d, "("); + btf_dump_emit_type_chain(d, decls, fname, lvl); + if (!multidim) + btf_dump_printf(d, ")"); + btf_dump_printf(d, "[%u]", a->nelems); + return; + } + case BTF_KIND_FUNC_PROTO: { + const struct btf_param *p = btf_params(t); + __u16 vlen = btf_vlen(t); + int i; + + /* + * GCC emits extra volatile qualifier for + * __attribute__((noreturn)) function pointers. Clang + * doesn't do it. It's a GCC quirk for backwards + * compatibility with code written for GCC <2.5. So, + * similarly to extra qualifiers for array, just drop + * them, instead of handling them. + */ + btf_dump_drop_mods(d, decls); + if (decls->cnt) { + btf_dump_printf(d, " ("); + btf_dump_emit_type_chain(d, decls, fname, lvl); + btf_dump_printf(d, ")"); + } else { + btf_dump_emit_name(d, fname, last_was_ptr); + } + btf_dump_printf(d, "("); + /* + * Clang for BPF target generates func_proto with no + * args as a func_proto with a single void arg (e.g., + * `int (*f)(void)` vs just `int (*f)()`). We are + * going to pretend there are no args for such case. + */ + if (vlen == 1 && p->type == 0) { + btf_dump_printf(d, ")"); + return; + } + + for (i = 0; i < vlen; i++, p++) { + if (i > 0) + btf_dump_printf(d, ", "); + + /* last arg of type void is vararg */ + if (i == vlen - 1 && p->type == 0) { + btf_dump_printf(d, "..."); + break; + } + + name = btf_name_of(d, p->name_off); + btf_dump_emit_type_decl(d, p->type, name, lvl); + } + + btf_dump_printf(d, ")"); + return; + } + default: + pr_warn("unexpected type in decl chain, kind:%u, id:[%u]\n", + kind, id); + return; + } + + last_was_ptr = kind == BTF_KIND_PTR; + } + + btf_dump_emit_name(d, fname, last_was_ptr); +} + +/* return number of duplicates (occurrences) of a given name */ +static size_t btf_dump_name_dups(struct btf_dump *d, struct hashmap *name_map, + const char *orig_name) +{ + char *old_name, *new_name; + size_t dup_cnt = 0; + int err; + + new_name = strdup(orig_name); + if (!new_name) + return 1; + + hashmap__find(name_map, orig_name, (void **)&dup_cnt); + dup_cnt++; + + err = hashmap__set(name_map, new_name, (void *)dup_cnt, + (const void **)&old_name, NULL); + if (err) + free(new_name); + + free(old_name); + + return dup_cnt; +} + +static const char *btf_dump_resolve_name(struct btf_dump *d, __u32 id, + struct hashmap *name_map) +{ + struct btf_dump_type_aux_state *s = &d->type_states[id]; + const struct btf_type *t = btf__type_by_id(d->btf, id); + const char *orig_name = btf_name_of(d, t->name_off); + const char **cached_name = &d->cached_names[id]; + size_t dup_cnt; + + if (t->name_off == 0) + return ""; + + if (s->name_resolved) + return *cached_name ? *cached_name : orig_name; + + if (btf_is_fwd(t) || (btf_is_enum(t) && btf_vlen(t) == 0)) { + s->name_resolved = 1; + return orig_name; + } + + dup_cnt = btf_dump_name_dups(d, name_map, orig_name); + if (dup_cnt > 1) { + const size_t max_len = 256; + char new_name[max_len]; + + snprintf(new_name, max_len, "%s___%zu", orig_name, dup_cnt); + *cached_name = strdup(new_name); + } + + s->name_resolved = 1; + return *cached_name ? *cached_name : orig_name; +} + +static const char *btf_dump_type_name(struct btf_dump *d, __u32 id) +{ + return btf_dump_resolve_name(d, id, d->type_names); +} + +static const char *btf_dump_ident_name(struct btf_dump *d, __u32 id) +{ + return btf_dump_resolve_name(d, id, d->ident_names); +} diff --git a/tools/lib/bpf/hashmap.c b/tools/lib/bpf/hashmap.c new file mode 100644 index 000000000..3c20b126d --- /dev/null +++ b/tools/lib/bpf/hashmap.c @@ -0,0 +1,241 @@ +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) + +/* + * Generic non-thread safe hash map implementation. + * + * Copyright (c) 2019 Facebook + */ +#include <stdint.h> +#include <stdlib.h> +#include <stdio.h> +#include <errno.h> +#include <linux/err.h> +#include "hashmap.h" + +/* make sure libbpf doesn't use kernel-only integer typedefs */ +#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 + +/* prevent accidental re-addition of reallocarray() */ +#pragma GCC poison reallocarray + +/* start with 4 buckets */ +#define HASHMAP_MIN_CAP_BITS 2 + +static void hashmap_add_entry(struct hashmap_entry **pprev, + struct hashmap_entry *entry) +{ + entry->next = *pprev; + *pprev = entry; +} + +static void hashmap_del_entry(struct hashmap_entry **pprev, + struct hashmap_entry *entry) +{ + *pprev = entry->next; + entry->next = NULL; +} + +void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn, + hashmap_equal_fn equal_fn, void *ctx) +{ + map->hash_fn = hash_fn; + map->equal_fn = equal_fn; + map->ctx = ctx; + + map->buckets = NULL; + map->cap = 0; + map->cap_bits = 0; + map->sz = 0; +} + +struct hashmap *hashmap__new(hashmap_hash_fn hash_fn, + hashmap_equal_fn equal_fn, + void *ctx) +{ + struct hashmap *map = malloc(sizeof(struct hashmap)); + + if (!map) + return ERR_PTR(-ENOMEM); + hashmap__init(map, hash_fn, equal_fn, ctx); + return map; +} + +void hashmap__clear(struct hashmap *map) +{ + struct hashmap_entry *cur, *tmp; + size_t bkt; + + hashmap__for_each_entry_safe(map, cur, tmp, bkt) { + free(cur); + } + free(map->buckets); + map->buckets = NULL; + map->cap = map->cap_bits = map->sz = 0; +} + +void hashmap__free(struct hashmap *map) +{ + if (!map) + return; + + hashmap__clear(map); + free(map); +} + +size_t hashmap__size(const struct hashmap *map) +{ + return map->sz; +} + +size_t hashmap__capacity(const struct hashmap *map) +{ + return map->cap; +} + +static bool hashmap_needs_to_grow(struct hashmap *map) +{ + /* grow if empty or more than 75% filled */ + return (map->cap == 0) || ((map->sz + 1) * 4 / 3 > map->cap); +} + +static int hashmap_grow(struct hashmap *map) +{ + struct hashmap_entry **new_buckets; + struct hashmap_entry *cur, *tmp; + size_t new_cap_bits, new_cap; + size_t h, bkt; + + new_cap_bits = map->cap_bits + 1; + if (new_cap_bits < HASHMAP_MIN_CAP_BITS) + new_cap_bits = HASHMAP_MIN_CAP_BITS; + + new_cap = 1UL << new_cap_bits; + new_buckets = calloc(new_cap, sizeof(new_buckets[0])); + if (!new_buckets) + return -ENOMEM; + + hashmap__for_each_entry_safe(map, cur, tmp, bkt) { + h = hash_bits(map->hash_fn(cur->key, map->ctx), new_cap_bits); + hashmap_add_entry(&new_buckets[h], cur); + } + + map->cap = new_cap; + map->cap_bits = new_cap_bits; + free(map->buckets); + map->buckets = new_buckets; + + return 0; +} + +static bool hashmap_find_entry(const struct hashmap *map, + const void *key, size_t hash, + struct hashmap_entry ***pprev, + struct hashmap_entry **entry) +{ + struct hashmap_entry *cur, **prev_ptr; + + if (!map->buckets) + return false; + + for (prev_ptr = &map->buckets[hash], cur = *prev_ptr; + cur; + prev_ptr = &cur->next, cur = cur->next) { + if (map->equal_fn(cur->key, key, map->ctx)) { + if (pprev) + *pprev = prev_ptr; + *entry = cur; + return true; + } + } + + return false; +} + +int hashmap__insert(struct hashmap *map, const void *key, void *value, + enum hashmap_insert_strategy strategy, + const void **old_key, void **old_value) +{ + struct hashmap_entry *entry; + size_t h; + int err; + + if (old_key) + *old_key = NULL; + if (old_value) + *old_value = NULL; + + h = hash_bits(map->hash_fn(key, map->ctx), map->cap_bits); + if (strategy != HASHMAP_APPEND && + hashmap_find_entry(map, key, h, NULL, &entry)) { + if (old_key) + *old_key = entry->key; + if (old_value) + *old_value = entry->value; + + if (strategy == HASHMAP_SET || strategy == HASHMAP_UPDATE) { + entry->key = key; + entry->value = value; + return 0; + } else if (strategy == HASHMAP_ADD) { + return -EEXIST; + } + } + + if (strategy == HASHMAP_UPDATE) + return -ENOENT; + + if (hashmap_needs_to_grow(map)) { + err = hashmap_grow(map); + if (err) + return err; + h = hash_bits(map->hash_fn(key, map->ctx), map->cap_bits); + } + + entry = malloc(sizeof(struct hashmap_entry)); + if (!entry) + return -ENOMEM; + + entry->key = key; + entry->value = value; + hashmap_add_entry(&map->buckets[h], entry); + map->sz++; + + return 0; +} + +bool hashmap__find(const struct hashmap *map, const void *key, void **value) +{ + struct hashmap_entry *entry; + size_t h; + + h = hash_bits(map->hash_fn(key, map->ctx), map->cap_bits); + if (!hashmap_find_entry(map, key, h, NULL, &entry)) + return false; + + if (value) + *value = entry->value; + return true; +} + +bool hashmap__delete(struct hashmap *map, const void *key, + const void **old_key, void **old_value) +{ + struct hashmap_entry **pprev, *entry; + size_t h; + + h = hash_bits(map->hash_fn(key, map->ctx), map->cap_bits); + if (!hashmap_find_entry(map, key, h, &pprev, &entry)) + return false; + + if (old_key) + *old_key = entry->key; + if (old_value) + *old_value = entry->value; + + hashmap_del_entry(pprev, entry); + free(entry); + map->sz--; + + return true; +} + diff --git a/tools/lib/bpf/hashmap.h b/tools/lib/bpf/hashmap.h new file mode 100644 index 000000000..10a4c4cd1 --- /dev/null +++ b/tools/lib/bpf/hashmap.h @@ -0,0 +1,195 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ + +/* + * Generic non-thread safe hash map implementation. + * + * Copyright (c) 2019 Facebook + */ +#ifndef __LIBBPF_HASHMAP_H +#define __LIBBPF_HASHMAP_H + +#include <stdbool.h> +#include <stddef.h> +#include <limits.h> + +static inline size_t hash_bits(size_t h, int bits) +{ + /* shuffle bits and return requested number of upper bits */ + if (bits == 0) + return 0; + +#if (__SIZEOF_SIZE_T__ == __SIZEOF_LONG_LONG__) + /* LP64 case */ + return (h * 11400714819323198485llu) >> (__SIZEOF_LONG_LONG__ * 8 - bits); +#elif (__SIZEOF_SIZE_T__ <= __SIZEOF_LONG__) + return (h * 2654435769lu) >> (__SIZEOF_LONG__ * 8 - bits); +#else +# error "Unsupported size_t size" +#endif +} + +/* generic C-string hashing function */ +static inline size_t str_hash(const char *s) +{ + size_t h = 0; + + while (*s) { + h = h * 31 + *s; + s++; + } + return h; +} + +typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx); +typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx); + +struct hashmap_entry { + const void *key; + void *value; + struct hashmap_entry *next; +}; + +struct hashmap { + hashmap_hash_fn hash_fn; + hashmap_equal_fn equal_fn; + void *ctx; + + struct hashmap_entry **buckets; + size_t cap; + size_t cap_bits; + size_t sz; +}; + +#define HASHMAP_INIT(hash_fn, equal_fn, ctx) { \ + .hash_fn = (hash_fn), \ + .equal_fn = (equal_fn), \ + .ctx = (ctx), \ + .buckets = NULL, \ + .cap = 0, \ + .cap_bits = 0, \ + .sz = 0, \ +} + +void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn, + hashmap_equal_fn equal_fn, void *ctx); +struct hashmap *hashmap__new(hashmap_hash_fn hash_fn, + hashmap_equal_fn equal_fn, + void *ctx); +void hashmap__clear(struct hashmap *map); +void hashmap__free(struct hashmap *map); + +size_t hashmap__size(const struct hashmap *map); +size_t hashmap__capacity(const struct hashmap *map); + +/* + * Hashmap insertion strategy: + * - HASHMAP_ADD - only add key/value if key doesn't exist yet; + * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise, + * update value; + * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do + * nothing and return -ENOENT; + * - HASHMAP_APPEND - always add key/value pair, even if key already exists. + * This turns hashmap into a multimap by allowing multiple values to be + * associated with the same key. Most useful read API for such hashmap is + * hashmap__for_each_key_entry() iteration. If hashmap__find() is still + * used, it will return last inserted key/value entry (first in a bucket + * chain). + */ +enum hashmap_insert_strategy { + HASHMAP_ADD, + HASHMAP_SET, + HASHMAP_UPDATE, + HASHMAP_APPEND, +}; + +/* + * hashmap__insert() adds key/value entry w/ various semantics, depending on + * provided strategy value. If a given key/value pair replaced already + * existing key/value pair, both old key and old value will be returned + * through old_key and old_value to allow calling code do proper memory + * management. + */ +int hashmap__insert(struct hashmap *map, const void *key, void *value, + enum hashmap_insert_strategy strategy, + const void **old_key, void **old_value); + +static inline int hashmap__add(struct hashmap *map, + const void *key, void *value) +{ + return hashmap__insert(map, key, value, HASHMAP_ADD, NULL, NULL); +} + +static inline int hashmap__set(struct hashmap *map, + const void *key, void *value, + const void **old_key, void **old_value) +{ + return hashmap__insert(map, key, value, HASHMAP_SET, + old_key, old_value); +} + +static inline int hashmap__update(struct hashmap *map, + const void *key, void *value, + const void **old_key, void **old_value) +{ + return hashmap__insert(map, key, value, HASHMAP_UPDATE, + old_key, old_value); +} + +static inline int hashmap__append(struct hashmap *map, + const void *key, void *value) +{ + return hashmap__insert(map, key, value, HASHMAP_APPEND, NULL, NULL); +} + +bool hashmap__delete(struct hashmap *map, const void *key, + const void **old_key, void **old_value); + +bool hashmap__find(const struct hashmap *map, const void *key, void **value); + +/* + * hashmap__for_each_entry - iterate over all entries in hashmap + * @map: hashmap to iterate + * @cur: struct hashmap_entry * used as a loop cursor + * @bkt: integer used as a bucket loop cursor + */ +#define hashmap__for_each_entry(map, cur, bkt) \ + for (bkt = 0; bkt < map->cap; bkt++) \ + for (cur = map->buckets[bkt]; cur; cur = cur->next) + +/* + * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe + * against removals + * @map: hashmap to iterate + * @cur: struct hashmap_entry * used as a loop cursor + * @tmp: struct hashmap_entry * used as a temporary next cursor storage + * @bkt: integer used as a bucket loop cursor + */ +#define hashmap__for_each_entry_safe(map, cur, tmp, bkt) \ + for (bkt = 0; bkt < map->cap; bkt++) \ + for (cur = map->buckets[bkt]; \ + cur && ({tmp = cur->next; true; }); \ + cur = tmp) + +/* + * hashmap__for_each_key_entry - iterate over entries associated with given key + * @map: hashmap to iterate + * @cur: struct hashmap_entry * used as a loop cursor + * @key: key to iterate entries for + */ +#define hashmap__for_each_key_entry(map, cur, _key) \ + for (cur = map->buckets \ + ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \ + : NULL; \ + cur; \ + cur = cur->next) \ + if (map->equal_fn(cur->key, (_key), map->ctx)) + +#define hashmap__for_each_key_entry_safe(map, cur, tmp, _key) \ + for (cur = map->buckets \ + ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \ + : NULL; \ + cur && ({ tmp = cur->next; true; }); \ + cur = tmp) \ + if (map->equal_fn(cur->key, (_key), map->ctx)) + +#endif /* __LIBBPF_HASHMAP_H */ diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c new file mode 100644 index 000000000..015ed8253 --- /dev/null +++ b/tools/lib/bpf/libbpf.c @@ -0,0 +1,10952 @@ +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) + +/* + * Common eBPF ELF object loading operations. + * + * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org> + * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com> + * Copyright (C) 2015 Huawei Inc. + * Copyright (C) 2017 Nicira, Inc. + * Copyright (C) 2019 Isovalent, Inc. + */ + +#ifndef _GNU_SOURCE +#define _GNU_SOURCE +#endif +#include <stdlib.h> +#include <stdio.h> +#include <stdarg.h> +#include <libgen.h> +#include <inttypes.h> +#include <limits.h> +#include <string.h> +#include <unistd.h> +#include <endian.h> +#include <fcntl.h> +#include <errno.h> +#include <ctype.h> +#include <asm/unistd.h> +#include <linux/err.h> +#include <linux/kernel.h> +#include <linux/bpf.h> +#include <linux/btf.h> +#include <linux/filter.h> +#include <linux/list.h> +#include <linux/limits.h> +#include <linux/perf_event.h> +#include <linux/ring_buffer.h> +#include <linux/version.h> +#include <sys/epoll.h> +#include <sys/ioctl.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <sys/vfs.h> +#include <sys/utsname.h> +#include <sys/resource.h> +#include <libelf.h> +#include <gelf.h> +#include <zlib.h> + +#include "libbpf.h" +#include "bpf.h" +#include "btf.h" +#include "str_error.h" +#include "libbpf_internal.h" +#include "hashmap.h" + +#ifndef EM_BPF +#define EM_BPF 247 +#endif + +#ifndef BPF_FS_MAGIC +#define BPF_FS_MAGIC 0xcafe4a11 +#endif + +#define BPF_INSN_SZ (sizeof(struct bpf_insn)) + +/* vsprintf() in __base_pr() uses nonliteral format string. It may break + * compilation if user enables corresponding warning. Disable it explicitly. + */ +#pragma GCC diagnostic ignored "-Wformat-nonliteral" + +#define __printf(a, b) __attribute__((format(printf, a, b))) + +static struct bpf_map *bpf_object__add_map(struct bpf_object *obj); +static const struct btf_type * +skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id); + +static int __base_pr(enum libbpf_print_level level, const char *format, + va_list args) +{ + if (level == LIBBPF_DEBUG) + return 0; + + return vfprintf(stderr, format, args); +} + +static libbpf_print_fn_t __libbpf_pr = __base_pr; + +libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn) +{ + libbpf_print_fn_t old_print_fn = __libbpf_pr; + + __libbpf_pr = fn; + return old_print_fn; +} + +__printf(2, 3) +void libbpf_print(enum libbpf_print_level level, const char *format, ...) +{ + va_list args; + + if (!__libbpf_pr) + return; + + va_start(args, format); + __libbpf_pr(level, format, args); + va_end(args); +} + +static void pr_perm_msg(int err) +{ + struct rlimit limit; + char buf[100]; + + if (err != -EPERM || geteuid() != 0) + return; + + err = getrlimit(RLIMIT_MEMLOCK, &limit); + if (err) + return; + + if (limit.rlim_cur == RLIM_INFINITY) + return; + + if (limit.rlim_cur < 1024) + snprintf(buf, sizeof(buf), "%zu bytes", (size_t)limit.rlim_cur); + else if (limit.rlim_cur < 1024*1024) + snprintf(buf, sizeof(buf), "%.1f KiB", (double)limit.rlim_cur / 1024); + else + snprintf(buf, sizeof(buf), "%.1f MiB", (double)limit.rlim_cur / (1024*1024)); + + pr_warn("permission error while running as root; try raising 'ulimit -l'? current value: %s\n", + buf); +} + +#define STRERR_BUFSIZE 128 + +/* Copied from tools/perf/util/util.h */ +#ifndef zfree +# define zfree(ptr) ({ free(*ptr); *ptr = NULL; }) +#endif + +#ifndef zclose +# define zclose(fd) ({ \ + int ___err = 0; \ + if ((fd) >= 0) \ + ___err = close((fd)); \ + fd = -1; \ + ___err; }) +#endif + +static inline __u64 ptr_to_u64(const void *ptr) +{ + return (__u64) (unsigned long) ptr; +} + +enum kern_feature_id { + /* v4.14: kernel support for program & map names. */ + FEAT_PROG_NAME, + /* v5.2: kernel support for global data sections. */ + FEAT_GLOBAL_DATA, + /* BTF support */ + FEAT_BTF, + /* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */ + FEAT_BTF_FUNC, + /* BTF_KIND_VAR and BTF_KIND_DATASEC support */ + FEAT_BTF_DATASEC, + /* BTF_FUNC_GLOBAL is supported */ + FEAT_BTF_GLOBAL_FUNC, + /* BPF_F_MMAPABLE is supported for arrays */ + FEAT_ARRAY_MMAP, + /* kernel support for expected_attach_type in BPF_PROG_LOAD */ + FEAT_EXP_ATTACH_TYPE, + /* bpf_probe_read_{kernel,user}[_str] helpers */ + FEAT_PROBE_READ_KERN, + /* BPF_PROG_BIND_MAP is supported */ + FEAT_PROG_BIND_MAP, + __FEAT_CNT, +}; + +static bool kernel_supports(enum kern_feature_id feat_id); + +enum reloc_type { + RELO_LD64, + RELO_CALL, + RELO_DATA, + RELO_EXTERN, +}; + +struct reloc_desc { + enum reloc_type type; + int insn_idx; + int map_idx; + int sym_off; + bool processed; +}; + +struct bpf_sec_def; + +typedef struct bpf_link *(*attach_fn_t)(const struct bpf_sec_def *sec, + struct bpf_program *prog); + +struct bpf_sec_def { + const char *sec; + size_t len; + enum bpf_prog_type prog_type; + enum bpf_attach_type expected_attach_type; + bool is_exp_attach_type_optional; + bool is_attachable; + bool is_attach_btf; + bool is_sleepable; + attach_fn_t attach_fn; +}; + +/* + * bpf_prog should be a better name but it has been used in + * linux/filter.h. + */ +struct bpf_program { + const struct bpf_sec_def *sec_def; + char *sec_name; + size_t sec_idx; + /* this program's instruction offset (in number of instructions) + * within its containing ELF section + */ + size_t sec_insn_off; + /* number of original instructions in ELF section belonging to this + * program, not taking into account subprogram instructions possible + * appended later during relocation + */ + size_t sec_insn_cnt; + /* Offset (in number of instructions) of the start of instruction + * belonging to this BPF program within its containing main BPF + * program. For the entry-point (main) BPF program, this is always + * zero. For a sub-program, this gets reset before each of main BPF + * programs are processed and relocated and is used to determined + * whether sub-program was already appended to the main program, and + * if yes, at which instruction offset. + */ + size_t sub_insn_off; + + char *name; + /* sec_name with / replaced by _; makes recursive pinning + * in bpf_object__pin_programs easier + */ + char *pin_name; + + /* instructions that belong to BPF program; insns[0] is located at + * sec_insn_off instruction within its ELF section in ELF file, so + * when mapping ELF file instruction index to the local instruction, + * one needs to subtract sec_insn_off; and vice versa. + */ + struct bpf_insn *insns; + /* actual number of instruction in this BPF program's image; for + * entry-point BPF programs this includes the size of main program + * itself plus all the used sub-programs, appended at the end + */ + size_t insns_cnt; + + struct reloc_desc *reloc_desc; + int nr_reloc; + int log_level; + + struct { + int nr; + int *fds; + } instances; + bpf_program_prep_t preprocessor; + + struct bpf_object *obj; + void *priv; + bpf_program_clear_priv_t clear_priv; + + bool load; + enum bpf_prog_type type; + enum bpf_attach_type expected_attach_type; + int prog_ifindex; + __u32 attach_btf_id; + __u32 attach_prog_fd; + void *func_info; + __u32 func_info_rec_size; + __u32 func_info_cnt; + + void *line_info; + __u32 line_info_rec_size; + __u32 line_info_cnt; + __u32 prog_flags; +}; + +struct bpf_struct_ops { + const char *tname; + const struct btf_type *type; + struct bpf_program **progs; + __u32 *kern_func_off; + /* e.g. struct tcp_congestion_ops in bpf_prog's btf format */ + void *data; + /* e.g. struct bpf_struct_ops_tcp_congestion_ops in + * btf_vmlinux's format. + * struct bpf_struct_ops_tcp_congestion_ops { + * [... some other kernel fields ...] + * struct tcp_congestion_ops data; + * } + * kern_vdata-size == sizeof(struct bpf_struct_ops_tcp_congestion_ops) + * bpf_map__init_kern_struct_ops() will populate the "kern_vdata" + * from "data". + */ + void *kern_vdata; + __u32 type_id; +}; + +#define DATA_SEC ".data" +#define BSS_SEC ".bss" +#define RODATA_SEC ".rodata" +#define KCONFIG_SEC ".kconfig" +#define KSYMS_SEC ".ksyms" +#define STRUCT_OPS_SEC ".struct_ops" + +enum libbpf_map_type { + LIBBPF_MAP_UNSPEC, + LIBBPF_MAP_DATA, + LIBBPF_MAP_BSS, + LIBBPF_MAP_RODATA, + LIBBPF_MAP_KCONFIG, +}; + +static const char * const libbpf_type_to_btf_name[] = { + [LIBBPF_MAP_DATA] = DATA_SEC, + [LIBBPF_MAP_BSS] = BSS_SEC, + [LIBBPF_MAP_RODATA] = RODATA_SEC, + [LIBBPF_MAP_KCONFIG] = KCONFIG_SEC, +}; + +struct bpf_map { + char *name; + int fd; + int sec_idx; + size_t sec_offset; + int map_ifindex; + int inner_map_fd; + struct bpf_map_def def; + __u32 numa_node; + __u32 btf_var_idx; + __u32 btf_key_type_id; + __u32 btf_value_type_id; + __u32 btf_vmlinux_value_type_id; + void *priv; + bpf_map_clear_priv_t clear_priv; + enum libbpf_map_type libbpf_type; + void *mmaped; + struct bpf_struct_ops *st_ops; + struct bpf_map *inner_map; + void **init_slots; + int init_slots_sz; + char *pin_path; + bool pinned; + bool reused; +}; + +enum extern_type { + EXT_UNKNOWN, + EXT_KCFG, + EXT_KSYM, +}; + +enum kcfg_type { + KCFG_UNKNOWN, + KCFG_CHAR, + KCFG_BOOL, + KCFG_INT, + KCFG_TRISTATE, + KCFG_CHAR_ARR, +}; + +struct extern_desc { + enum extern_type type; + int sym_idx; + int btf_id; + int sec_btf_id; + const char *name; + bool is_set; + bool is_weak; + union { + struct { + enum kcfg_type type; + int sz; + int align; + int data_off; + bool is_signed; + } kcfg; + struct { + unsigned long long addr; + + /* target btf_id of the corresponding kernel var. */ + int vmlinux_btf_id; + + /* local btf_id of the ksym extern's type. */ + __u32 type_id; + } ksym; + }; +}; + +static LIST_HEAD(bpf_objects_list); + +struct bpf_object { + char name[BPF_OBJ_NAME_LEN]; + char license[64]; + __u32 kern_version; + + struct bpf_program *programs; + size_t nr_programs; + struct bpf_map *maps; + size_t nr_maps; + size_t maps_cap; + + char *kconfig; + struct extern_desc *externs; + int nr_extern; + int kconfig_map_idx; + int rodata_map_idx; + + bool loaded; + bool has_subcalls; + + /* + * Information when doing elf related work. Only valid if fd + * is valid. + */ + struct { + int fd; + const void *obj_buf; + size_t obj_buf_sz; + Elf *elf; + GElf_Ehdr ehdr; + Elf_Data *symbols; + Elf_Data *data; + Elf_Data *rodata; + Elf_Data *bss; + Elf_Data *st_ops_data; + size_t shstrndx; /* section index for section name strings */ + size_t strtabidx; + struct { + GElf_Shdr shdr; + Elf_Data *data; + } *reloc_sects; + int nr_reloc_sects; + int maps_shndx; + int btf_maps_shndx; + __u32 btf_maps_sec_btf_id; + int text_shndx; + int symbols_shndx; + int data_shndx; + int rodata_shndx; + int bss_shndx; + int st_ops_shndx; + } efile; + /* + * All loaded bpf_object is linked in a list, which is + * hidden to caller. bpf_objects__<func> handlers deal with + * all objects. + */ + struct list_head list; + + struct btf *btf; + /* Parse and load BTF vmlinux if any of the programs in the object need + * it at load time. + */ + struct btf *btf_vmlinux; + struct btf_ext *btf_ext; + + void *priv; + bpf_object_clear_priv_t clear_priv; + + char path[]; +}; +#define obj_elf_valid(o) ((o)->efile.elf) + +static const char *elf_sym_str(const struct bpf_object *obj, size_t off); +static const char *elf_sec_str(const struct bpf_object *obj, size_t off); +static Elf_Scn *elf_sec_by_idx(const struct bpf_object *obj, size_t idx); +static Elf_Scn *elf_sec_by_name(const struct bpf_object *obj, const char *name); +static int elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn, GElf_Shdr *hdr); +static const char *elf_sec_name(const struct bpf_object *obj, Elf_Scn *scn); +static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn); +static int elf_sym_by_sec_off(const struct bpf_object *obj, size_t sec_idx, + size_t off, __u32 sym_type, GElf_Sym *sym); + +void bpf_program__unload(struct bpf_program *prog) +{ + int i; + + if (!prog) + return; + + /* + * If the object is opened but the program was never loaded, + * it is possible that prog->instances.nr == -1. + */ + if (prog->instances.nr > 0) { + for (i = 0; i < prog->instances.nr; i++) + zclose(prog->instances.fds[i]); + } else if (prog->instances.nr != -1) { + pr_warn("Internal error: instances.nr is %d\n", + prog->instances.nr); + } + + prog->instances.nr = -1; + zfree(&prog->instances.fds); + + zfree(&prog->func_info); + zfree(&prog->line_info); +} + +static void bpf_program__exit(struct bpf_program *prog) +{ + if (!prog) + return; + + if (prog->clear_priv) + prog->clear_priv(prog, prog->priv); + + prog->priv = NULL; + prog->clear_priv = NULL; + + bpf_program__unload(prog); + zfree(&prog->name); + zfree(&prog->sec_name); + zfree(&prog->pin_name); + zfree(&prog->insns); + zfree(&prog->reloc_desc); + + prog->nr_reloc = 0; + prog->insns_cnt = 0; + prog->sec_idx = -1; +} + +static char *__bpf_program__pin_name(struct bpf_program *prog) +{ + char *name, *p; + + name = p = strdup(prog->sec_name); + while ((p = strchr(p, '/'))) + *p = '_'; + + return name; +} + +static bool insn_is_subprog_call(const struct bpf_insn *insn) +{ + return BPF_CLASS(insn->code) == BPF_JMP && + BPF_OP(insn->code) == BPF_CALL && + BPF_SRC(insn->code) == BPF_K && + insn->src_reg == BPF_PSEUDO_CALL && + insn->dst_reg == 0 && + insn->off == 0; +} + +static int +bpf_object__init_prog(struct bpf_object *obj, struct bpf_program *prog, + const char *name, size_t sec_idx, const char *sec_name, + size_t sec_off, void *insn_data, size_t insn_data_sz) +{ + if (insn_data_sz == 0 || insn_data_sz % BPF_INSN_SZ || sec_off % BPF_INSN_SZ) { + pr_warn("sec '%s': corrupted program '%s', offset %zu, size %zu\n", + sec_name, name, sec_off, insn_data_sz); + return -EINVAL; + } + + memset(prog, 0, sizeof(*prog)); + prog->obj = obj; + + prog->sec_idx = sec_idx; + prog->sec_insn_off = sec_off / BPF_INSN_SZ; + prog->sec_insn_cnt = insn_data_sz / BPF_INSN_SZ; + /* insns_cnt can later be increased by appending used subprograms */ + prog->insns_cnt = prog->sec_insn_cnt; + + prog->type = BPF_PROG_TYPE_UNSPEC; + prog->load = true; + + prog->instances.fds = NULL; + prog->instances.nr = -1; + + prog->sec_name = strdup(sec_name); + if (!prog->sec_name) + goto errout; + + prog->name = strdup(name); + if (!prog->name) + goto errout; + + prog->pin_name = __bpf_program__pin_name(prog); + if (!prog->pin_name) + goto errout; + + prog->insns = malloc(insn_data_sz); + if (!prog->insns) + goto errout; + memcpy(prog->insns, insn_data, insn_data_sz); + + return 0; +errout: + pr_warn("sec '%s': failed to allocate memory for prog '%s'\n", sec_name, name); + bpf_program__exit(prog); + return -ENOMEM; +} + +static int +bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data, + const char *sec_name, int sec_idx) +{ + struct bpf_program *prog, *progs; + void *data = sec_data->d_buf; + size_t sec_sz = sec_data->d_size, sec_off, prog_sz; + int nr_progs, err; + const char *name; + GElf_Sym sym; + + progs = obj->programs; + nr_progs = obj->nr_programs; + sec_off = 0; + + while (sec_off < sec_sz) { + if (elf_sym_by_sec_off(obj, sec_idx, sec_off, STT_FUNC, &sym)) { + pr_warn("sec '%s': failed to find program symbol at offset %zu\n", + sec_name, sec_off); + return -LIBBPF_ERRNO__FORMAT; + } + + prog_sz = sym.st_size; + + name = elf_sym_str(obj, sym.st_name); + if (!name) { + pr_warn("sec '%s': failed to get symbol name for offset %zu\n", + sec_name, sec_off); + return -LIBBPF_ERRNO__FORMAT; + } + + if (sec_off + prog_sz > sec_sz) { + pr_warn("sec '%s': program at offset %zu crosses section boundary\n", + sec_name, sec_off); + return -LIBBPF_ERRNO__FORMAT; + } + + pr_debug("sec '%s': found program '%s' at insn offset %zu (%zu bytes), code size %zu insns (%zu bytes)\n", + sec_name, name, sec_off / BPF_INSN_SZ, sec_off, prog_sz / BPF_INSN_SZ, prog_sz); + + progs = libbpf_reallocarray(progs, nr_progs + 1, sizeof(*progs)); + if (!progs) { + /* + * In this case the original obj->programs + * is still valid, so don't need special treat for + * bpf_close_object(). + */ + pr_warn("sec '%s': failed to alloc memory for new program '%s'\n", + sec_name, name); + return -ENOMEM; + } + obj->programs = progs; + + prog = &progs[nr_progs]; + + err = bpf_object__init_prog(obj, prog, name, sec_idx, sec_name, + sec_off, data + sec_off, prog_sz); + if (err) + return err; + + nr_progs++; + obj->nr_programs = nr_progs; + + sec_off += prog_sz; + } + + return 0; +} + +static __u32 get_kernel_version(void) +{ + __u32 major, minor, patch; + struct utsname info; + + uname(&info); + if (sscanf(info.release, "%u.%u.%u", &major, &minor, &patch) != 3) + return 0; + return KERNEL_VERSION(major, minor, patch); +} + +static const struct btf_member * +find_member_by_offset(const struct btf_type *t, __u32 bit_offset) +{ + struct btf_member *m; + int i; + + for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) { + if (btf_member_bit_offset(t, i) == bit_offset) + return m; + } + + return NULL; +} + +static const struct btf_member * +find_member_by_name(const struct btf *btf, const struct btf_type *t, + const char *name) +{ + struct btf_member *m; + int i; + + for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) { + if (!strcmp(btf__name_by_offset(btf, m->name_off), name)) + return m; + } + + return NULL; +} + +#define STRUCT_OPS_VALUE_PREFIX "bpf_struct_ops_" +static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix, + const char *name, __u32 kind); + +static int +find_struct_ops_kern_types(const struct btf *btf, const char *tname, + const struct btf_type **type, __u32 *type_id, + const struct btf_type **vtype, __u32 *vtype_id, + const struct btf_member **data_member) +{ + const struct btf_type *kern_type, *kern_vtype; + const struct btf_member *kern_data_member; + __s32 kern_vtype_id, kern_type_id; + __u32 i; + + kern_type_id = btf__find_by_name_kind(btf, tname, BTF_KIND_STRUCT); + if (kern_type_id < 0) { + pr_warn("struct_ops init_kern: struct %s is not found in kernel BTF\n", + tname); + return kern_type_id; + } + kern_type = btf__type_by_id(btf, kern_type_id); + + /* Find the corresponding "map_value" type that will be used + * in map_update(BPF_MAP_TYPE_STRUCT_OPS). For example, + * find "struct bpf_struct_ops_tcp_congestion_ops" from the + * btf_vmlinux. + */ + kern_vtype_id = find_btf_by_prefix_kind(btf, STRUCT_OPS_VALUE_PREFIX, + tname, BTF_KIND_STRUCT); + if (kern_vtype_id < 0) { + pr_warn("struct_ops init_kern: struct %s%s is not found in kernel BTF\n", + STRUCT_OPS_VALUE_PREFIX, tname); + return kern_vtype_id; + } + kern_vtype = btf__type_by_id(btf, kern_vtype_id); + + /* Find "struct tcp_congestion_ops" from + * struct bpf_struct_ops_tcp_congestion_ops { + * [ ... ] + * struct tcp_congestion_ops data; + * } + */ + kern_data_member = btf_members(kern_vtype); + for (i = 0; i < btf_vlen(kern_vtype); i++, kern_data_member++) { + if (kern_data_member->type == kern_type_id) + break; + } + if (i == btf_vlen(kern_vtype)) { + pr_warn("struct_ops init_kern: struct %s data is not found in struct %s%s\n", + tname, STRUCT_OPS_VALUE_PREFIX, tname); + return -EINVAL; + } + + *type = kern_type; + *type_id = kern_type_id; + *vtype = kern_vtype; + *vtype_id = kern_vtype_id; + *data_member = kern_data_member; + + return 0; +} + +static bool bpf_map__is_struct_ops(const struct bpf_map *map) +{ + return map->def.type == BPF_MAP_TYPE_STRUCT_OPS; +} + +/* Init the map's fields that depend on kern_btf */ +static int bpf_map__init_kern_struct_ops(struct bpf_map *map, + const struct btf *btf, + const struct btf *kern_btf) +{ + const struct btf_member *member, *kern_member, *kern_data_member; + const struct btf_type *type, *kern_type, *kern_vtype; + __u32 i, kern_type_id, kern_vtype_id, kern_data_off; + struct bpf_struct_ops *st_ops; + void *data, *kern_data; + const char *tname; + int err; + + st_ops = map->st_ops; + type = st_ops->type; + tname = st_ops->tname; + err = find_struct_ops_kern_types(kern_btf, tname, + &kern_type, &kern_type_id, + &kern_vtype, &kern_vtype_id, + &kern_data_member); + if (err) + return err; + + pr_debug("struct_ops init_kern %s: type_id:%u kern_type_id:%u kern_vtype_id:%u\n", + map->name, st_ops->type_id, kern_type_id, kern_vtype_id); + + map->def.value_size = kern_vtype->size; + map->btf_vmlinux_value_type_id = kern_vtype_id; + + st_ops->kern_vdata = calloc(1, kern_vtype->size); + if (!st_ops->kern_vdata) + return -ENOMEM; + + data = st_ops->data; + kern_data_off = kern_data_member->offset / 8; + kern_data = st_ops->kern_vdata + kern_data_off; + + member = btf_members(type); + for (i = 0; i < btf_vlen(type); i++, member++) { + const struct btf_type *mtype, *kern_mtype; + __u32 mtype_id, kern_mtype_id; + void *mdata, *kern_mdata; + __s64 msize, kern_msize; + __u32 moff, kern_moff; + __u32 kern_member_idx; + const char *mname; + + mname = btf__name_by_offset(btf, member->name_off); + kern_member = find_member_by_name(kern_btf, kern_type, mname); + if (!kern_member) { + pr_warn("struct_ops init_kern %s: Cannot find member %s in kernel BTF\n", + map->name, mname); + return -ENOTSUP; + } + + kern_member_idx = kern_member - btf_members(kern_type); + if (btf_member_bitfield_size(type, i) || + btf_member_bitfield_size(kern_type, kern_member_idx)) { + pr_warn("struct_ops init_kern %s: bitfield %s is not supported\n", + map->name, mname); + return -ENOTSUP; + } + + moff = member->offset / 8; + kern_moff = kern_member->offset / 8; + + mdata = data + moff; + kern_mdata = kern_data + kern_moff; + + mtype = skip_mods_and_typedefs(btf, member->type, &mtype_id); + kern_mtype = skip_mods_and_typedefs(kern_btf, kern_member->type, + &kern_mtype_id); + if (BTF_INFO_KIND(mtype->info) != + BTF_INFO_KIND(kern_mtype->info)) { + pr_warn("struct_ops init_kern %s: Unmatched member type %s %u != %u(kernel)\n", + map->name, mname, BTF_INFO_KIND(mtype->info), + BTF_INFO_KIND(kern_mtype->info)); + return -ENOTSUP; + } + + if (btf_is_ptr(mtype)) { + struct bpf_program *prog; + + prog = st_ops->progs[i]; + if (!prog) + continue; + + kern_mtype = skip_mods_and_typedefs(kern_btf, + kern_mtype->type, + &kern_mtype_id); + + /* mtype->type must be a func_proto which was + * guaranteed in bpf_object__collect_st_ops_relos(), + * so only check kern_mtype for func_proto here. + */ + if (!btf_is_func_proto(kern_mtype)) { + pr_warn("struct_ops init_kern %s: kernel member %s is not a func ptr\n", + map->name, mname); + return -ENOTSUP; + } + + prog->attach_btf_id = kern_type_id; + prog->expected_attach_type = kern_member_idx; + + st_ops->kern_func_off[i] = kern_data_off + kern_moff; + + pr_debug("struct_ops init_kern %s: func ptr %s is set to prog %s from data(+%u) to kern_data(+%u)\n", + map->name, mname, prog->name, moff, + kern_moff); + + continue; + } + + msize = btf__resolve_size(btf, mtype_id); + kern_msize = btf__resolve_size(kern_btf, kern_mtype_id); + if (msize < 0 || kern_msize < 0 || msize != kern_msize) { + pr_warn("struct_ops init_kern %s: Error in size of member %s: %zd != %zd(kernel)\n", + map->name, mname, (ssize_t)msize, + (ssize_t)kern_msize); + return -ENOTSUP; + } + + pr_debug("struct_ops init_kern %s: copy %s %u bytes from data(+%u) to kern_data(+%u)\n", + map->name, mname, (unsigned int)msize, + moff, kern_moff); + memcpy(kern_mdata, mdata, msize); + } + + return 0; +} + +static int bpf_object__init_kern_struct_ops_maps(struct bpf_object *obj) +{ + struct bpf_map *map; + size_t i; + int err; + + for (i = 0; i < obj->nr_maps; i++) { + map = &obj->maps[i]; + + if (!bpf_map__is_struct_ops(map)) + continue; + + err = bpf_map__init_kern_struct_ops(map, obj->btf, + obj->btf_vmlinux); + if (err) + return err; + } + + return 0; +} + +static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) +{ + const struct btf_type *type, *datasec; + const struct btf_var_secinfo *vsi; + struct bpf_struct_ops *st_ops; + const char *tname, *var_name; + __s32 type_id, datasec_id; + const struct btf *btf; + struct bpf_map *map; + __u32 i; + + if (obj->efile.st_ops_shndx == -1) + return 0; + + btf = obj->btf; + datasec_id = btf__find_by_name_kind(btf, STRUCT_OPS_SEC, + BTF_KIND_DATASEC); + if (datasec_id < 0) { + pr_warn("struct_ops init: DATASEC %s not found\n", + STRUCT_OPS_SEC); + return -EINVAL; + } + + datasec = btf__type_by_id(btf, datasec_id); + vsi = btf_var_secinfos(datasec); + for (i = 0; i < btf_vlen(datasec); i++, vsi++) { + type = btf__type_by_id(obj->btf, vsi->type); + var_name = btf__name_by_offset(obj->btf, type->name_off); + + type_id = btf__resolve_type(obj->btf, vsi->type); + if (type_id < 0) { + pr_warn("struct_ops init: Cannot resolve var type_id %u in DATASEC %s\n", + vsi->type, STRUCT_OPS_SEC); + return -EINVAL; + } + + type = btf__type_by_id(obj->btf, type_id); + tname = btf__name_by_offset(obj->btf, type->name_off); + if (!tname[0]) { + pr_warn("struct_ops init: anonymous type is not supported\n"); + return -ENOTSUP; + } + if (!btf_is_struct(type)) { + pr_warn("struct_ops init: %s is not a struct\n", tname); + return -EINVAL; + } + + map = bpf_object__add_map(obj); + if (IS_ERR(map)) + return PTR_ERR(map); + + map->sec_idx = obj->efile.st_ops_shndx; + map->sec_offset = vsi->offset; + map->name = strdup(var_name); + if (!map->name) + return -ENOMEM; + + map->def.type = BPF_MAP_TYPE_STRUCT_OPS; + map->def.key_size = sizeof(int); + map->def.value_size = type->size; + map->def.max_entries = 1; + + map->st_ops = calloc(1, sizeof(*map->st_ops)); + if (!map->st_ops) + return -ENOMEM; + st_ops = map->st_ops; + st_ops->data = malloc(type->size); + st_ops->progs = calloc(btf_vlen(type), sizeof(*st_ops->progs)); + st_ops->kern_func_off = malloc(btf_vlen(type) * + sizeof(*st_ops->kern_func_off)); + if (!st_ops->data || !st_ops->progs || !st_ops->kern_func_off) + return -ENOMEM; + + if (vsi->offset + type->size > obj->efile.st_ops_data->d_size) { + pr_warn("struct_ops init: var %s is beyond the end of DATASEC %s\n", + var_name, STRUCT_OPS_SEC); + return -EINVAL; + } + + memcpy(st_ops->data, + obj->efile.st_ops_data->d_buf + vsi->offset, + type->size); + st_ops->tname = tname; + st_ops->type = type; + st_ops->type_id = type_id; + + pr_debug("struct_ops init: struct %s(type_id=%u) %s found at offset %u\n", + tname, type_id, var_name, vsi->offset); + } + + return 0; +} + +static struct bpf_object *bpf_object__new(const char *path, + const void *obj_buf, + size_t obj_buf_sz, + const char *obj_name) +{ + struct bpf_object *obj; + char *end; + + obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1); + if (!obj) { + pr_warn("alloc memory failed for %s\n", path); + return ERR_PTR(-ENOMEM); + } + + strcpy(obj->path, path); + if (obj_name) { + strncpy(obj->name, obj_name, sizeof(obj->name) - 1); + obj->name[sizeof(obj->name) - 1] = 0; + } else { + /* Using basename() GNU version which doesn't modify arg. */ + strncpy(obj->name, basename((void *)path), + sizeof(obj->name) - 1); + end = strchr(obj->name, '.'); + if (end) + *end = 0; + } + + obj->efile.fd = -1; + /* + * Caller of this function should also call + * bpf_object__elf_finish() after data collection to return + * obj_buf to user. If not, we should duplicate the buffer to + * avoid user freeing them before elf finish. + */ + obj->efile.obj_buf = obj_buf; + obj->efile.obj_buf_sz = obj_buf_sz; + obj->efile.maps_shndx = -1; + obj->efile.btf_maps_shndx = -1; + obj->efile.data_shndx = -1; + obj->efile.rodata_shndx = -1; + obj->efile.bss_shndx = -1; + obj->efile.st_ops_shndx = -1; + obj->kconfig_map_idx = -1; + obj->rodata_map_idx = -1; + + obj->kern_version = get_kernel_version(); + obj->loaded = false; + + INIT_LIST_HEAD(&obj->list); + list_add(&obj->list, &bpf_objects_list); + return obj; +} + +static void bpf_object__elf_finish(struct bpf_object *obj) +{ + if (!obj_elf_valid(obj)) + return; + + if (obj->efile.elf) { + elf_end(obj->efile.elf); + obj->efile.elf = NULL; + } + obj->efile.symbols = NULL; + obj->efile.data = NULL; + obj->efile.rodata = NULL; + obj->efile.bss = NULL; + obj->efile.st_ops_data = NULL; + + zfree(&obj->efile.reloc_sects); + obj->efile.nr_reloc_sects = 0; + zclose(obj->efile.fd); + obj->efile.obj_buf = NULL; + obj->efile.obj_buf_sz = 0; +} + +/* if libelf is old and doesn't support mmap(), fall back to read() */ +#ifndef ELF_C_READ_MMAP +#define ELF_C_READ_MMAP ELF_C_READ +#endif + +static int bpf_object__elf_init(struct bpf_object *obj) +{ + int err = 0; + GElf_Ehdr *ep; + + if (obj_elf_valid(obj)) { + pr_warn("elf: init internal error\n"); + return -LIBBPF_ERRNO__LIBELF; + } + + if (obj->efile.obj_buf_sz > 0) { + /* + * obj_buf should have been validated by + * bpf_object__open_buffer(). + */ + obj->efile.elf = elf_memory((char *)obj->efile.obj_buf, + obj->efile.obj_buf_sz); + } else { + obj->efile.fd = open(obj->path, O_RDONLY); + if (obj->efile.fd < 0) { + char errmsg[STRERR_BUFSIZE], *cp; + + err = -errno; + cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); + pr_warn("elf: failed to open %s: %s\n", obj->path, cp); + return err; + } + + obj->efile.elf = elf_begin(obj->efile.fd, ELF_C_READ_MMAP, NULL); + } + + if (!obj->efile.elf) { + pr_warn("elf: failed to open %s as ELF file: %s\n", obj->path, elf_errmsg(-1)); + err = -LIBBPF_ERRNO__LIBELF; + goto errout; + } + + if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) { + pr_warn("elf: failed to get ELF header from %s: %s\n", obj->path, elf_errmsg(-1)); + err = -LIBBPF_ERRNO__FORMAT; + goto errout; + } + ep = &obj->efile.ehdr; + + if (elf_getshdrstrndx(obj->efile.elf, &obj->efile.shstrndx)) { + pr_warn("elf: failed to get section names section index for %s: %s\n", + obj->path, elf_errmsg(-1)); + err = -LIBBPF_ERRNO__FORMAT; + goto errout; + } + + /* Elf is corrupted/truncated, avoid calling elf_strptr. */ + if (!elf_rawdata(elf_getscn(obj->efile.elf, obj->efile.shstrndx), NULL)) { + pr_warn("elf: failed to get section names strings from %s: %s\n", + obj->path, elf_errmsg(-1)); + err = -LIBBPF_ERRNO__FORMAT; + goto errout; + } + + /* Old LLVM set e_machine to EM_NONE */ + if (ep->e_type != ET_REL || + (ep->e_machine && ep->e_machine != EM_BPF)) { + pr_warn("elf: %s is not a valid eBPF object file\n", obj->path); + err = -LIBBPF_ERRNO__FORMAT; + goto errout; + } + + return 0; +errout: + bpf_object__elf_finish(obj); + return err; +} + +static int bpf_object__check_endianness(struct bpf_object *obj) +{ +#if __BYTE_ORDER == __LITTLE_ENDIAN + if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2LSB) + return 0; +#elif __BYTE_ORDER == __BIG_ENDIAN + if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2MSB) + return 0; +#else +# error "Unrecognized __BYTE_ORDER__" +#endif + pr_warn("elf: endianness mismatch in %s.\n", obj->path); + return -LIBBPF_ERRNO__ENDIAN; +} + +static int +bpf_object__init_license(struct bpf_object *obj, void *data, size_t size) +{ + memcpy(obj->license, data, min(size, sizeof(obj->license) - 1)); + pr_debug("license of %s is %s\n", obj->path, obj->license); + return 0; +} + +static int +bpf_object__init_kversion(struct bpf_object *obj, void *data, size_t size) +{ + __u32 kver; + + if (size != sizeof(kver)) { + pr_warn("invalid kver section in %s\n", obj->path); + return -LIBBPF_ERRNO__FORMAT; + } + memcpy(&kver, data, sizeof(kver)); + obj->kern_version = kver; + pr_debug("kernel version of %s is %x\n", obj->path, obj->kern_version); + return 0; +} + +static bool bpf_map_type__is_map_in_map(enum bpf_map_type type) +{ + if (type == BPF_MAP_TYPE_ARRAY_OF_MAPS || + type == BPF_MAP_TYPE_HASH_OF_MAPS) + return true; + return false; +} + +int bpf_object__section_size(const struct bpf_object *obj, const char *name, + __u32 *size) +{ + int ret = -ENOENT; + + *size = 0; + if (!name) { + return -EINVAL; + } else if (!strcmp(name, DATA_SEC)) { + if (obj->efile.data) + *size = obj->efile.data->d_size; + } else if (!strcmp(name, BSS_SEC)) { + if (obj->efile.bss) + *size = obj->efile.bss->d_size; + } else if (!strcmp(name, RODATA_SEC)) { + if (obj->efile.rodata) + *size = obj->efile.rodata->d_size; + } else if (!strcmp(name, STRUCT_OPS_SEC)) { + if (obj->efile.st_ops_data) + *size = obj->efile.st_ops_data->d_size; + } else { + Elf_Scn *scn = elf_sec_by_name(obj, name); + Elf_Data *data = elf_sec_data(obj, scn); + + if (data) { + ret = 0; /* found it */ + *size = data->d_size; + } + } + + return *size ? 0 : ret; +} + +int bpf_object__variable_offset(const struct bpf_object *obj, const char *name, + __u32 *off) +{ + Elf_Data *symbols = obj->efile.symbols; + const char *sname; + size_t si; + + if (!name || !off) + return -EINVAL; + + for (si = 0; si < symbols->d_size / sizeof(GElf_Sym); si++) { + GElf_Sym sym; + + if (!gelf_getsym(symbols, si, &sym)) + continue; + if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL || + GELF_ST_TYPE(sym.st_info) != STT_OBJECT) + continue; + + sname = elf_sym_str(obj, sym.st_name); + if (!sname) { + pr_warn("failed to get sym name string for var %s\n", + name); + return -EIO; + } + if (strcmp(name, sname) == 0) { + *off = sym.st_value; + return 0; + } + } + + return -ENOENT; +} + +static struct bpf_map *bpf_object__add_map(struct bpf_object *obj) +{ + struct bpf_map *new_maps; + size_t new_cap; + int i; + + if (obj->nr_maps < obj->maps_cap) + return &obj->maps[obj->nr_maps++]; + + new_cap = max((size_t)4, obj->maps_cap * 3 / 2); + new_maps = libbpf_reallocarray(obj->maps, new_cap, sizeof(*obj->maps)); + if (!new_maps) { + pr_warn("alloc maps for object failed\n"); + return ERR_PTR(-ENOMEM); + } + + obj->maps_cap = new_cap; + obj->maps = new_maps; + + /* zero out new maps */ + memset(obj->maps + obj->nr_maps, 0, + (obj->maps_cap - obj->nr_maps) * sizeof(*obj->maps)); + /* + * fill all fd with -1 so won't close incorrect fd (fd=0 is stdin) + * when failure (zclose won't close negative fd)). + */ + for (i = obj->nr_maps; i < obj->maps_cap; i++) { + obj->maps[i].fd = -1; + obj->maps[i].inner_map_fd = -1; + } + + return &obj->maps[obj->nr_maps++]; +} + +static size_t bpf_map_mmap_sz(const struct bpf_map *map) +{ + long page_sz = sysconf(_SC_PAGE_SIZE); + size_t map_sz; + + map_sz = (size_t)roundup(map->def.value_size, 8) * map->def.max_entries; + map_sz = roundup(map_sz, page_sz); + return map_sz; +} + +static char *internal_map_name(struct bpf_object *obj, + enum libbpf_map_type type) +{ + char map_name[BPF_OBJ_NAME_LEN], *p; + const char *sfx = libbpf_type_to_btf_name[type]; + int sfx_len = max((size_t)7, strlen(sfx)); + int pfx_len = min((size_t)BPF_OBJ_NAME_LEN - sfx_len - 1, + strlen(obj->name)); + + snprintf(map_name, sizeof(map_name), "%.*s%.*s", pfx_len, obj->name, + sfx_len, libbpf_type_to_btf_name[type]); + + /* sanitise map name to characters allowed by kernel */ + for (p = map_name; *p && p < map_name + sizeof(map_name); p++) + if (!isalnum(*p) && *p != '_' && *p != '.') + *p = '_'; + + return strdup(map_name); +} + +static int +bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type, + int sec_idx, void *data, size_t data_sz) +{ + struct bpf_map_def *def; + struct bpf_map *map; + int err; + + map = bpf_object__add_map(obj); + if (IS_ERR(map)) + return PTR_ERR(map); + + map->libbpf_type = type; + map->sec_idx = sec_idx; + map->sec_offset = 0; + map->name = internal_map_name(obj, type); + if (!map->name) { + pr_warn("failed to alloc map name\n"); + return -ENOMEM; + } + + def = &map->def; + def->type = BPF_MAP_TYPE_ARRAY; + def->key_size = sizeof(int); + def->value_size = data_sz; + def->max_entries = 1; + def->map_flags = type == LIBBPF_MAP_RODATA || type == LIBBPF_MAP_KCONFIG + ? BPF_F_RDONLY_PROG : 0; + def->map_flags |= BPF_F_MMAPABLE; + + pr_debug("map '%s' (global data): at sec_idx %d, offset %zu, flags %x.\n", + map->name, map->sec_idx, map->sec_offset, def->map_flags); + + map->mmaped = mmap(NULL, bpf_map_mmap_sz(map), PROT_READ | PROT_WRITE, + MAP_SHARED | MAP_ANONYMOUS, -1, 0); + if (map->mmaped == MAP_FAILED) { + err = -errno; + map->mmaped = NULL; + pr_warn("failed to alloc map '%s' content buffer: %d\n", + map->name, err); + zfree(&map->name); + return err; + } + + if (data) + memcpy(map->mmaped, data, data_sz); + + pr_debug("map %td is \"%s\"\n", map - obj->maps, map->name); + return 0; +} + +static int bpf_object__init_global_data_maps(struct bpf_object *obj) +{ + int err; + + /* + * Populate obj->maps with libbpf internal maps. + */ + if (obj->efile.data_shndx >= 0) { + err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA, + obj->efile.data_shndx, + obj->efile.data->d_buf, + obj->efile.data->d_size); + if (err) + return err; + } + if (obj->efile.rodata_shndx >= 0) { + err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA, + obj->efile.rodata_shndx, + obj->efile.rodata->d_buf, + obj->efile.rodata->d_size); + if (err) + return err; + + obj->rodata_map_idx = obj->nr_maps - 1; + } + if (obj->efile.bss_shndx >= 0) { + err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS, + obj->efile.bss_shndx, + NULL, + obj->efile.bss->d_size); + if (err) + return err; + } + return 0; +} + + +static struct extern_desc *find_extern_by_name(const struct bpf_object *obj, + const void *name) +{ + int i; + + for (i = 0; i < obj->nr_extern; i++) { + if (strcmp(obj->externs[i].name, name) == 0) + return &obj->externs[i]; + } + return NULL; +} + +static int set_kcfg_value_tri(struct extern_desc *ext, void *ext_val, + char value) +{ + switch (ext->kcfg.type) { + case KCFG_BOOL: + if (value == 'm') { + pr_warn("extern (kcfg) %s=%c should be tristate or char\n", + ext->name, value); + return -EINVAL; + } + *(bool *)ext_val = value == 'y' ? true : false; + break; + case KCFG_TRISTATE: + if (value == 'y') + *(enum libbpf_tristate *)ext_val = TRI_YES; + else if (value == 'm') + *(enum libbpf_tristate *)ext_val = TRI_MODULE; + else /* value == 'n' */ + *(enum libbpf_tristate *)ext_val = TRI_NO; + break; + case KCFG_CHAR: + *(char *)ext_val = value; + break; + case KCFG_UNKNOWN: + case KCFG_INT: + case KCFG_CHAR_ARR: + default: + pr_warn("extern (kcfg) %s=%c should be bool, tristate, or char\n", + ext->name, value); + return -EINVAL; + } + ext->is_set = true; + return 0; +} + +static int set_kcfg_value_str(struct extern_desc *ext, char *ext_val, + const char *value) +{ + size_t len; + + if (ext->kcfg.type != KCFG_CHAR_ARR) { + pr_warn("extern (kcfg) %s=%s should be char array\n", ext->name, value); + return -EINVAL; + } + + len = strlen(value); + if (value[len - 1] != '"') { + pr_warn("extern (kcfg) '%s': invalid string config '%s'\n", + ext->name, value); + return -EINVAL; + } + + /* strip quotes */ + len -= 2; + if (len >= ext->kcfg.sz) { + pr_warn("extern (kcfg) '%s': long string config %s of (%zu bytes) truncated to %d bytes\n", + ext->name, value, len, ext->kcfg.sz - 1); + len = ext->kcfg.sz - 1; + } + memcpy(ext_val, value + 1, len); + ext_val[len] = '\0'; + ext->is_set = true; + return 0; +} + +static int parse_u64(const char *value, __u64 *res) +{ + char *value_end; + int err; + + errno = 0; + *res = strtoull(value, &value_end, 0); + if (errno) { + err = -errno; + pr_warn("failed to parse '%s' as integer: %d\n", value, err); + return err; + } + if (*value_end) { + pr_warn("failed to parse '%s' as integer completely\n", value); + return -EINVAL; + } + return 0; +} + +static bool is_kcfg_value_in_range(const struct extern_desc *ext, __u64 v) +{ + int bit_sz = ext->kcfg.sz * 8; + + if (ext->kcfg.sz == 8) + return true; + + /* Validate that value stored in u64 fits in integer of `ext->sz` + * bytes size without any loss of information. If the target integer + * is signed, we rely on the following limits of integer type of + * Y bits and subsequent transformation: + * + * -2^(Y-1) <= X <= 2^(Y-1) - 1 + * 0 <= X + 2^(Y-1) <= 2^Y - 1 + * 0 <= X + 2^(Y-1) < 2^Y + * + * For unsigned target integer, check that all the (64 - Y) bits are + * zero. + */ + if (ext->kcfg.is_signed) + return v + (1ULL << (bit_sz - 1)) < (1ULL << bit_sz); + else + return (v >> bit_sz) == 0; +} + +static int set_kcfg_value_num(struct extern_desc *ext, void *ext_val, + __u64 value) +{ + if (ext->kcfg.type != KCFG_INT && ext->kcfg.type != KCFG_CHAR) { + pr_warn("extern (kcfg) %s=%llu should be integer\n", + ext->name, (unsigned long long)value); + return -EINVAL; + } + if (!is_kcfg_value_in_range(ext, value)) { + pr_warn("extern (kcfg) %s=%llu value doesn't fit in %d bytes\n", + ext->name, (unsigned long long)value, ext->kcfg.sz); + return -ERANGE; + } + switch (ext->kcfg.sz) { + case 1: *(__u8 *)ext_val = value; break; + case 2: *(__u16 *)ext_val = value; break; + case 4: *(__u32 *)ext_val = value; break; + case 8: *(__u64 *)ext_val = value; break; + default: + return -EINVAL; + } + ext->is_set = true; + return 0; +} + +static int bpf_object__process_kconfig_line(struct bpf_object *obj, + char *buf, void *data) +{ + struct extern_desc *ext; + char *sep, *value; + int len, err = 0; + void *ext_val; + __u64 num; + + if (strncmp(buf, "CONFIG_", 7)) + return 0; + + sep = strchr(buf, '='); + if (!sep) { + pr_warn("failed to parse '%s': no separator\n", buf); + return -EINVAL; + } + + /* Trim ending '\n' */ + len = strlen(buf); + if (buf[len - 1] == '\n') + buf[len - 1] = '\0'; + /* Split on '=' and ensure that a value is present. */ + *sep = '\0'; + if (!sep[1]) { + *sep = '='; + pr_warn("failed to parse '%s': no value\n", buf); + return -EINVAL; + } + + ext = find_extern_by_name(obj, buf); + if (!ext || ext->is_set) + return 0; + + ext_val = data + ext->kcfg.data_off; + value = sep + 1; + + switch (*value) { + case 'y': case 'n': case 'm': + err = set_kcfg_value_tri(ext, ext_val, *value); + break; + case '"': + err = set_kcfg_value_str(ext, ext_val, value); + break; + default: + /* assume integer */ + err = parse_u64(value, &num); + if (err) { + pr_warn("extern (kcfg) %s=%s should be integer\n", + ext->name, value); + return err; + } + err = set_kcfg_value_num(ext, ext_val, num); + break; + } + if (err) + return err; + pr_debug("extern (kcfg) %s=%s\n", ext->name, value); + return 0; +} + +static int bpf_object__read_kconfig_file(struct bpf_object *obj, void *data) +{ + char buf[PATH_MAX]; + struct utsname uts; + int len, err = 0; + gzFile file; + + uname(&uts); + len = snprintf(buf, PATH_MAX, "/boot/config-%s", uts.release); + if (len < 0) + return -EINVAL; + else if (len >= PATH_MAX) + return -ENAMETOOLONG; + + /* gzopen also accepts uncompressed files. */ + file = gzopen(buf, "r"); + if (!file) + file = gzopen("/proc/config.gz", "r"); + + if (!file) { + pr_warn("failed to open system Kconfig\n"); + return -ENOENT; + } + + while (gzgets(file, buf, sizeof(buf))) { + err = bpf_object__process_kconfig_line(obj, buf, data); + if (err) { + pr_warn("error parsing system Kconfig line '%s': %d\n", + buf, err); + goto out; + } + } + +out: + gzclose(file); + return err; +} + +static int bpf_object__read_kconfig_mem(struct bpf_object *obj, + const char *config, void *data) +{ + char buf[PATH_MAX]; + int err = 0; + FILE *file; + + file = fmemopen((void *)config, strlen(config), "r"); + if (!file) { + err = -errno; + pr_warn("failed to open in-memory Kconfig: %d\n", err); + return err; + } + + while (fgets(buf, sizeof(buf), file)) { + err = bpf_object__process_kconfig_line(obj, buf, data); + if (err) { + pr_warn("error parsing in-memory Kconfig line '%s': %d\n", + buf, err); + break; + } + } + + fclose(file); + return err; +} + +static int bpf_object__init_kconfig_map(struct bpf_object *obj) +{ + struct extern_desc *last_ext = NULL, *ext; + size_t map_sz; + int i, err; + + for (i = 0; i < obj->nr_extern; i++) { + ext = &obj->externs[i]; + if (ext->type == EXT_KCFG) + last_ext = ext; + } + + if (!last_ext) + return 0; + + map_sz = last_ext->kcfg.data_off + last_ext->kcfg.sz; + err = bpf_object__init_internal_map(obj, LIBBPF_MAP_KCONFIG, + obj->efile.symbols_shndx, + NULL, map_sz); + if (err) + return err; + + obj->kconfig_map_idx = obj->nr_maps - 1; + + return 0; +} + +static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict) +{ + Elf_Data *symbols = obj->efile.symbols; + int i, map_def_sz = 0, nr_maps = 0, nr_syms; + Elf_Data *data = NULL; + Elf_Scn *scn; + + if (obj->efile.maps_shndx < 0) + return 0; + + if (!symbols) + return -EINVAL; + + + scn = elf_sec_by_idx(obj, obj->efile.maps_shndx); + data = elf_sec_data(obj, scn); + if (!scn || !data) { + pr_warn("elf: failed to get legacy map definitions for %s\n", + obj->path); + return -EINVAL; + } + + /* + * Count number of maps. Each map has a name. + * Array of maps is not supported: only the first element is + * considered. + * + * TODO: Detect array of map and report error. + */ + nr_syms = symbols->d_size / sizeof(GElf_Sym); + for (i = 0; i < nr_syms; i++) { + GElf_Sym sym; + + if (!gelf_getsym(symbols, i, &sym)) + continue; + if (sym.st_shndx != obj->efile.maps_shndx) + continue; + nr_maps++; + } + /* Assume equally sized map definitions */ + pr_debug("elf: found %d legacy map definitions (%zd bytes) in %s\n", + nr_maps, data->d_size, obj->path); + + if (!data->d_size || nr_maps == 0 || (data->d_size % nr_maps) != 0) { + pr_warn("elf: unable to determine legacy map definition size in %s\n", + obj->path); + return -EINVAL; + } + map_def_sz = data->d_size / nr_maps; + + /* Fill obj->maps using data in "maps" section. */ + for (i = 0; i < nr_syms; i++) { + GElf_Sym sym; + const char *map_name; + struct bpf_map_def *def; + struct bpf_map *map; + + if (!gelf_getsym(symbols, i, &sym)) + continue; + if (sym.st_shndx != obj->efile.maps_shndx) + continue; + + map = bpf_object__add_map(obj); + if (IS_ERR(map)) + return PTR_ERR(map); + + map_name = elf_sym_str(obj, sym.st_name); + if (!map_name) { + pr_warn("failed to get map #%d name sym string for obj %s\n", + i, obj->path); + return -LIBBPF_ERRNO__FORMAT; + } + + map->libbpf_type = LIBBPF_MAP_UNSPEC; + map->sec_idx = sym.st_shndx; + map->sec_offset = sym.st_value; + pr_debug("map '%s' (legacy): at sec_idx %d, offset %zu.\n", + map_name, map->sec_idx, map->sec_offset); + if (sym.st_value + map_def_sz > data->d_size) { + pr_warn("corrupted maps section in %s: last map \"%s\" too small\n", + obj->path, map_name); + return -EINVAL; + } + + map->name = strdup(map_name); + if (!map->name) { + pr_warn("failed to alloc map name\n"); + return -ENOMEM; + } + pr_debug("map %d is \"%s\"\n", i, map->name); + def = (struct bpf_map_def *)(data->d_buf + sym.st_value); + /* + * If the definition of the map in the object file fits in + * bpf_map_def, copy it. Any extra fields in our version + * of bpf_map_def will default to zero as a result of the + * calloc above. + */ + if (map_def_sz <= sizeof(struct bpf_map_def)) { + memcpy(&map->def, def, map_def_sz); + } else { + /* + * Here the map structure being read is bigger than what + * we expect, truncate if the excess bits are all zero. + * If they are not zero, reject this map as + * incompatible. + */ + char *b; + + for (b = ((char *)def) + sizeof(struct bpf_map_def); + b < ((char *)def) + map_def_sz; b++) { + if (*b != 0) { + pr_warn("maps section in %s: \"%s\" has unrecognized, non-zero options\n", + obj->path, map_name); + if (strict) + return -EINVAL; + } + } + memcpy(&map->def, def, sizeof(struct bpf_map_def)); + } + } + return 0; +} + +static const struct btf_type * +skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id) +{ + const struct btf_type *t = btf__type_by_id(btf, id); + + if (res_id) + *res_id = id; + + while (btf_is_mod(t) || btf_is_typedef(t)) { + if (res_id) + *res_id = t->type; + t = btf__type_by_id(btf, t->type); + } + + return t; +} + +static const struct btf_type * +resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id) +{ + const struct btf_type *t; + + t = skip_mods_and_typedefs(btf, id, NULL); + if (!btf_is_ptr(t)) + return NULL; + + t = skip_mods_and_typedefs(btf, t->type, res_id); + + return btf_is_func_proto(t) ? t : NULL; +} + +static const char *btf_kind_str(const struct btf_type *t) +{ + switch (btf_kind(t)) { + case BTF_KIND_UNKN: return "void"; + case BTF_KIND_INT: return "int"; + case BTF_KIND_PTR: return "ptr"; + case BTF_KIND_ARRAY: return "array"; + case BTF_KIND_STRUCT: return "struct"; + case BTF_KIND_UNION: return "union"; + case BTF_KIND_ENUM: return "enum"; + case BTF_KIND_FWD: return "fwd"; + case BTF_KIND_TYPEDEF: return "typedef"; + case BTF_KIND_VOLATILE: return "volatile"; + case BTF_KIND_CONST: return "const"; + case BTF_KIND_RESTRICT: return "restrict"; + case BTF_KIND_FUNC: return "func"; + case BTF_KIND_FUNC_PROTO: return "func_proto"; + case BTF_KIND_VAR: return "var"; + case BTF_KIND_DATASEC: return "datasec"; + default: return "unknown"; + } +} + +/* + * Fetch integer attribute of BTF map definition. Such attributes are + * represented using a pointer to an array, in which dimensionality of array + * encodes specified integer value. E.g., int (*type)[BPF_MAP_TYPE_ARRAY]; + * encodes `type => BPF_MAP_TYPE_ARRAY` key/value pair completely using BTF + * type definition, while using only sizeof(void *) space in ELF data section. + */ +static bool get_map_field_int(const char *map_name, const struct btf *btf, + const struct btf_member *m, __u32 *res) +{ + const struct btf_type *t = skip_mods_and_typedefs(btf, m->type, NULL); + const char *name = btf__name_by_offset(btf, m->name_off); + const struct btf_array *arr_info; + const struct btf_type *arr_t; + + if (!btf_is_ptr(t)) { + pr_warn("map '%s': attr '%s': expected PTR, got %s.\n", + map_name, name, btf_kind_str(t)); + return false; + } + + arr_t = btf__type_by_id(btf, t->type); + if (!arr_t) { + pr_warn("map '%s': attr '%s': type [%u] not found.\n", + map_name, name, t->type); + return false; + } + if (!btf_is_array(arr_t)) { + pr_warn("map '%s': attr '%s': expected ARRAY, got %s.\n", + map_name, name, btf_kind_str(arr_t)); + return false; + } + arr_info = btf_array(arr_t); + *res = arr_info->nelems; + return true; +} + +static int build_map_pin_path(struct bpf_map *map, const char *path) +{ + char buf[PATH_MAX]; + int len; + + if (!path) + path = "/sys/fs/bpf"; + + len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map)); + if (len < 0) + return -EINVAL; + else if (len >= PATH_MAX) + return -ENAMETOOLONG; + + return bpf_map__set_pin_path(map, buf); +} + + +static int parse_btf_map_def(struct bpf_object *obj, + struct bpf_map *map, + const struct btf_type *def, + bool strict, bool is_inner, + const char *pin_root_path) +{ + const struct btf_type *t; + const struct btf_member *m; + int vlen, i; + + vlen = btf_vlen(def); + m = btf_members(def); + for (i = 0; i < vlen; i++, m++) { + const char *name = btf__name_by_offset(obj->btf, m->name_off); + + if (!name) { + pr_warn("map '%s': invalid field #%d.\n", map->name, i); + return -EINVAL; + } + if (strcmp(name, "type") == 0) { + if (!get_map_field_int(map->name, obj->btf, m, + &map->def.type)) + return -EINVAL; + pr_debug("map '%s': found type = %u.\n", + map->name, map->def.type); + } else if (strcmp(name, "max_entries") == 0) { + if (!get_map_field_int(map->name, obj->btf, m, + &map->def.max_entries)) + return -EINVAL; + pr_debug("map '%s': found max_entries = %u.\n", + map->name, map->def.max_entries); + } else if (strcmp(name, "map_flags") == 0) { + if (!get_map_field_int(map->name, obj->btf, m, + &map->def.map_flags)) + return -EINVAL; + pr_debug("map '%s': found map_flags = %u.\n", + map->name, map->def.map_flags); + } else if (strcmp(name, "numa_node") == 0) { + if (!get_map_field_int(map->name, obj->btf, m, &map->numa_node)) + return -EINVAL; + pr_debug("map '%s': found numa_node = %u.\n", map->name, map->numa_node); + } else if (strcmp(name, "key_size") == 0) { + __u32 sz; + + if (!get_map_field_int(map->name, obj->btf, m, &sz)) + return -EINVAL; + pr_debug("map '%s': found key_size = %u.\n", + map->name, sz); + if (map->def.key_size && map->def.key_size != sz) { + pr_warn("map '%s': conflicting key size %u != %u.\n", + map->name, map->def.key_size, sz); + return -EINVAL; + } + map->def.key_size = sz; + } else if (strcmp(name, "key") == 0) { + __s64 sz; + + t = btf__type_by_id(obj->btf, m->type); + if (!t) { + pr_warn("map '%s': key type [%d] not found.\n", + map->name, m->type); + return -EINVAL; + } + if (!btf_is_ptr(t)) { + pr_warn("map '%s': key spec is not PTR: %s.\n", + map->name, btf_kind_str(t)); + return -EINVAL; + } + sz = btf__resolve_size(obj->btf, t->type); + if (sz < 0) { + pr_warn("map '%s': can't determine key size for type [%u]: %zd.\n", + map->name, t->type, (ssize_t)sz); + return sz; + } + pr_debug("map '%s': found key [%u], sz = %zd.\n", + map->name, t->type, (ssize_t)sz); + if (map->def.key_size && map->def.key_size != sz) { + pr_warn("map '%s': conflicting key size %u != %zd.\n", + map->name, map->def.key_size, (ssize_t)sz); + return -EINVAL; + } + map->def.key_size = sz; + map->btf_key_type_id = t->type; + } else if (strcmp(name, "value_size") == 0) { + __u32 sz; + + if (!get_map_field_int(map->name, obj->btf, m, &sz)) + return -EINVAL; + pr_debug("map '%s': found value_size = %u.\n", + map->name, sz); + if (map->def.value_size && map->def.value_size != sz) { + pr_warn("map '%s': conflicting value size %u != %u.\n", + map->name, map->def.value_size, sz); + return -EINVAL; + } + map->def.value_size = sz; + } else if (strcmp(name, "value") == 0) { + __s64 sz; + + t = btf__type_by_id(obj->btf, m->type); + if (!t) { + pr_warn("map '%s': value type [%d] not found.\n", + map->name, m->type); + return -EINVAL; + } + if (!btf_is_ptr(t)) { + pr_warn("map '%s': value spec is not PTR: %s.\n", + map->name, btf_kind_str(t)); + return -EINVAL; + } + sz = btf__resolve_size(obj->btf, t->type); + if (sz < 0) { + pr_warn("map '%s': can't determine value size for type [%u]: %zd.\n", + map->name, t->type, (ssize_t)sz); + return sz; + } + pr_debug("map '%s': found value [%u], sz = %zd.\n", + map->name, t->type, (ssize_t)sz); + if (map->def.value_size && map->def.value_size != sz) { + pr_warn("map '%s': conflicting value size %u != %zd.\n", + map->name, map->def.value_size, (ssize_t)sz); + return -EINVAL; + } + map->def.value_size = sz; + map->btf_value_type_id = t->type; + } + else if (strcmp(name, "values") == 0) { + int err; + + if (is_inner) { + pr_warn("map '%s': multi-level inner maps not supported.\n", + map->name); + return -ENOTSUP; + } + if (i != vlen - 1) { + pr_warn("map '%s': '%s' member should be last.\n", + map->name, name); + return -EINVAL; + } + if (!bpf_map_type__is_map_in_map(map->def.type)) { + pr_warn("map '%s': should be map-in-map.\n", + map->name); + return -ENOTSUP; + } + if (map->def.value_size && map->def.value_size != 4) { + pr_warn("map '%s': conflicting value size %u != 4.\n", + map->name, map->def.value_size); + return -EINVAL; + } + map->def.value_size = 4; + t = btf__type_by_id(obj->btf, m->type); + if (!t) { + pr_warn("map '%s': map-in-map inner type [%d] not found.\n", + map->name, m->type); + return -EINVAL; + } + if (!btf_is_array(t) || btf_array(t)->nelems) { + pr_warn("map '%s': map-in-map inner spec is not a zero-sized array.\n", + map->name); + return -EINVAL; + } + t = skip_mods_and_typedefs(obj->btf, btf_array(t)->type, + NULL); + if (!btf_is_ptr(t)) { + pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n", + map->name, btf_kind_str(t)); + return -EINVAL; + } + t = skip_mods_and_typedefs(obj->btf, t->type, NULL); + if (!btf_is_struct(t)) { + pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n", + map->name, btf_kind_str(t)); + return -EINVAL; + } + + map->inner_map = calloc(1, sizeof(*map->inner_map)); + if (!map->inner_map) + return -ENOMEM; + map->inner_map->sec_idx = obj->efile.btf_maps_shndx; + map->inner_map->name = malloc(strlen(map->name) + + sizeof(".inner") + 1); + if (!map->inner_map->name) + return -ENOMEM; + sprintf(map->inner_map->name, "%s.inner", map->name); + + err = parse_btf_map_def(obj, map->inner_map, t, strict, + true /* is_inner */, NULL); + if (err) + return err; + } else if (strcmp(name, "pinning") == 0) { + __u32 val; + int err; + + if (is_inner) { + pr_debug("map '%s': inner def can't be pinned.\n", + map->name); + return -EINVAL; + } + if (!get_map_field_int(map->name, obj->btf, m, &val)) + return -EINVAL; + pr_debug("map '%s': found pinning = %u.\n", + map->name, val); + + if (val != LIBBPF_PIN_NONE && + val != LIBBPF_PIN_BY_NAME) { + pr_warn("map '%s': invalid pinning value %u.\n", + map->name, val); + return -EINVAL; + } + if (val == LIBBPF_PIN_BY_NAME) { + err = build_map_pin_path(map, pin_root_path); + if (err) { + pr_warn("map '%s': couldn't build pin path.\n", + map->name); + return err; + } + } + } else { + if (strict) { + pr_warn("map '%s': unknown field '%s'.\n", + map->name, name); + return -ENOTSUP; + } + pr_debug("map '%s': ignoring unknown field '%s'.\n", + map->name, name); + } + } + + if (map->def.type == BPF_MAP_TYPE_UNSPEC) { + pr_warn("map '%s': map type isn't specified.\n", map->name); + return -EINVAL; + } + + return 0; +} + +static int bpf_object__init_user_btf_map(struct bpf_object *obj, + const struct btf_type *sec, + int var_idx, int sec_idx, + const Elf_Data *data, bool strict, + const char *pin_root_path) +{ + const struct btf_type *var, *def; + const struct btf_var_secinfo *vi; + const struct btf_var *var_extra; + const char *map_name; + struct bpf_map *map; + + vi = btf_var_secinfos(sec) + var_idx; + var = btf__type_by_id(obj->btf, vi->type); + var_extra = btf_var(var); + map_name = btf__name_by_offset(obj->btf, var->name_off); + + if (map_name == NULL || map_name[0] == '\0') { + pr_warn("map #%d: empty name.\n", var_idx); + return -EINVAL; + } + if ((__u64)vi->offset + vi->size > data->d_size) { + pr_warn("map '%s' BTF data is corrupted.\n", map_name); + return -EINVAL; + } + if (!btf_is_var(var)) { + pr_warn("map '%s': unexpected var kind %s.\n", + map_name, btf_kind_str(var)); + return -EINVAL; + } + if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED && + var_extra->linkage != BTF_VAR_STATIC) { + pr_warn("map '%s': unsupported var linkage %u.\n", + map_name, var_extra->linkage); + return -EOPNOTSUPP; + } + + def = skip_mods_and_typedefs(obj->btf, var->type, NULL); + if (!btf_is_struct(def)) { + pr_warn("map '%s': unexpected def kind %s.\n", + map_name, btf_kind_str(var)); + return -EINVAL; + } + if (def->size > vi->size) { + pr_warn("map '%s': invalid def size.\n", map_name); + return -EINVAL; + } + + map = bpf_object__add_map(obj); + if (IS_ERR(map)) + return PTR_ERR(map); + map->name = strdup(map_name); + if (!map->name) { + pr_warn("map '%s': failed to alloc map name.\n", map_name); + return -ENOMEM; + } + map->libbpf_type = LIBBPF_MAP_UNSPEC; + map->def.type = BPF_MAP_TYPE_UNSPEC; + map->sec_idx = sec_idx; + map->sec_offset = vi->offset; + map->btf_var_idx = var_idx; + pr_debug("map '%s': at sec_idx %d, offset %zu.\n", + map_name, map->sec_idx, map->sec_offset); + + return parse_btf_map_def(obj, map, def, strict, false, pin_root_path); +} + +static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict, + const char *pin_root_path) +{ + const struct btf_type *sec = NULL; + int nr_types, i, vlen, err; + const struct btf_type *t; + const char *name; + Elf_Data *data; + Elf_Scn *scn; + + if (obj->efile.btf_maps_shndx < 0) + return 0; + + scn = elf_sec_by_idx(obj, obj->efile.btf_maps_shndx); + data = elf_sec_data(obj, scn); + if (!scn || !data) { + pr_warn("elf: failed to get %s map definitions for %s\n", + MAPS_ELF_SEC, obj->path); + return -EINVAL; + } + + nr_types = btf__get_nr_types(obj->btf); + for (i = 1; i <= nr_types; i++) { + t = btf__type_by_id(obj->btf, i); + if (!btf_is_datasec(t)) + continue; + name = btf__name_by_offset(obj->btf, t->name_off); + if (strcmp(name, MAPS_ELF_SEC) == 0) { + sec = t; + obj->efile.btf_maps_sec_btf_id = i; + break; + } + } + + if (!sec) { + pr_warn("DATASEC '%s' not found.\n", MAPS_ELF_SEC); + return -ENOENT; + } + + vlen = btf_vlen(sec); + for (i = 0; i < vlen; i++) { + err = bpf_object__init_user_btf_map(obj, sec, i, + obj->efile.btf_maps_shndx, + data, strict, + pin_root_path); + if (err) + return err; + } + + return 0; +} + +static int bpf_object__init_maps(struct bpf_object *obj, + const struct bpf_object_open_opts *opts) +{ + const char *pin_root_path; + bool strict; + int err; + + strict = !OPTS_GET(opts, relaxed_maps, false); + pin_root_path = OPTS_GET(opts, pin_root_path, NULL); + + err = bpf_object__init_user_maps(obj, strict); + err = err ?: bpf_object__init_user_btf_maps(obj, strict, pin_root_path); + err = err ?: bpf_object__init_global_data_maps(obj); + err = err ?: bpf_object__init_kconfig_map(obj); + err = err ?: bpf_object__init_struct_ops_maps(obj); + if (err) + return err; + + return 0; +} + +static bool section_have_execinstr(struct bpf_object *obj, int idx) +{ + GElf_Shdr sh; + + if (elf_sec_hdr(obj, elf_sec_by_idx(obj, idx), &sh)) + return false; + + return sh.sh_flags & SHF_EXECINSTR; +} + +static bool btf_needs_sanitization(struct bpf_object *obj) +{ + bool has_func_global = kernel_supports(FEAT_BTF_GLOBAL_FUNC); + bool has_datasec = kernel_supports(FEAT_BTF_DATASEC); + bool has_func = kernel_supports(FEAT_BTF_FUNC); + + return !has_func || !has_datasec || !has_func_global; +} + +static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) +{ + bool has_func_global = kernel_supports(FEAT_BTF_GLOBAL_FUNC); + bool has_datasec = kernel_supports(FEAT_BTF_DATASEC); + bool has_func = kernel_supports(FEAT_BTF_FUNC); + struct btf_type *t; + int i, j, vlen; + + for (i = 1; i <= btf__get_nr_types(btf); i++) { + t = (struct btf_type *)btf__type_by_id(btf, i); + + if (!has_datasec && btf_is_var(t)) { + /* replace VAR with INT */ + t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0); + /* + * using size = 1 is the safest choice, 4 will be too + * big and cause kernel BTF validation failure if + * original variable took less than 4 bytes + */ + t->size = 1; + *(int *)(t + 1) = BTF_INT_ENC(0, 0, 8); + } else if (!has_datasec && btf_is_datasec(t)) { + /* replace DATASEC with STRUCT */ + const struct btf_var_secinfo *v = btf_var_secinfos(t); + struct btf_member *m = btf_members(t); + struct btf_type *vt; + char *name; + + name = (char *)btf__name_by_offset(btf, t->name_off); + while (*name) { + if (*name == '.') + *name = '_'; + name++; + } + + vlen = btf_vlen(t); + t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, vlen); + for (j = 0; j < vlen; j++, v++, m++) { + /* order of field assignments is important */ + m->offset = v->offset * 8; + m->type = v->type; + /* preserve variable name as member name */ + vt = (void *)btf__type_by_id(btf, v->type); + m->name_off = vt->name_off; + } + } else if (!has_func && btf_is_func_proto(t)) { + /* replace FUNC_PROTO with ENUM */ + vlen = btf_vlen(t); + t->info = BTF_INFO_ENC(BTF_KIND_ENUM, 0, vlen); + t->size = sizeof(__u32); /* kernel enforced */ + } else if (!has_func && btf_is_func(t)) { + /* replace FUNC with TYPEDEF */ + t->info = BTF_INFO_ENC(BTF_KIND_TYPEDEF, 0, 0); + } else if (!has_func_global && btf_is_func(t)) { + /* replace BTF_FUNC_GLOBAL with BTF_FUNC_STATIC */ + t->info = BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0); + } + } +} + +static bool libbpf_needs_btf(const struct bpf_object *obj) +{ + return obj->efile.btf_maps_shndx >= 0 || + obj->efile.st_ops_shndx >= 0 || + obj->nr_extern > 0; +} + +static bool kernel_needs_btf(const struct bpf_object *obj) +{ + return obj->efile.st_ops_shndx >= 0; +} + +static int bpf_object__init_btf(struct bpf_object *obj, + Elf_Data *btf_data, + Elf_Data *btf_ext_data) +{ + int err = -ENOENT; + + if (btf_data) { + obj->btf = btf__new(btf_data->d_buf, btf_data->d_size); + if (IS_ERR(obj->btf)) { + err = PTR_ERR(obj->btf); + obj->btf = NULL; + pr_warn("Error loading ELF section %s: %d.\n", + BTF_ELF_SEC, err); + goto out; + } + /* enforce 8-byte pointers for BPF-targeted BTFs */ + btf__set_pointer_size(obj->btf, 8); + err = 0; + } + if (btf_ext_data) { + if (!obj->btf) { + pr_debug("Ignore ELF section %s because its depending ELF section %s is not found.\n", + BTF_EXT_ELF_SEC, BTF_ELF_SEC); + goto out; + } + obj->btf_ext = btf_ext__new(btf_ext_data->d_buf, + btf_ext_data->d_size); + if (IS_ERR(obj->btf_ext)) { + pr_warn("Error loading ELF section %s: %ld. Ignored and continue.\n", + BTF_EXT_ELF_SEC, PTR_ERR(obj->btf_ext)); + obj->btf_ext = NULL; + goto out; + } + } +out: + if (err && libbpf_needs_btf(obj)) { + pr_warn("BTF is required, but is missing or corrupted.\n"); + return err; + } + return 0; +} + +static int bpf_object__finalize_btf(struct bpf_object *obj) +{ + int err; + + if (!obj->btf) + return 0; + + err = btf__finalize_data(obj, obj->btf); + if (err) { + pr_warn("Error finalizing %s: %d.\n", BTF_ELF_SEC, err); + return err; + } + + return 0; +} + +static inline bool libbpf_prog_needs_vmlinux_btf(struct bpf_program *prog) +{ + if (prog->type == BPF_PROG_TYPE_STRUCT_OPS || + prog->type == BPF_PROG_TYPE_LSM) + return true; + + /* BPF_PROG_TYPE_TRACING programs which do not attach to other programs + * also need vmlinux BTF + */ + if (prog->type == BPF_PROG_TYPE_TRACING && !prog->attach_prog_fd) + return true; + + return false; +} + +static int bpf_object__load_vmlinux_btf(struct bpf_object *obj) +{ + bool need_vmlinux_btf = false; + struct bpf_program *prog; + int i, err; + + /* CO-RE relocations need kernel BTF */ + if (obj->btf_ext && obj->btf_ext->core_relo_info.len) + need_vmlinux_btf = true; + + /* Support for typed ksyms needs kernel BTF */ + for (i = 0; i < obj->nr_extern; i++) { + const struct extern_desc *ext; + + ext = &obj->externs[i]; + if (ext->type == EXT_KSYM && ext->ksym.type_id) { + need_vmlinux_btf = true; + break; + } + } + + bpf_object__for_each_program(prog, obj) { + if (!prog->load) + continue; + if (libbpf_prog_needs_vmlinux_btf(prog)) { + need_vmlinux_btf = true; + break; + } + } + + if (!need_vmlinux_btf) + return 0; + + obj->btf_vmlinux = libbpf_find_kernel_btf(); + if (IS_ERR(obj->btf_vmlinux)) { + err = PTR_ERR(obj->btf_vmlinux); + pr_warn("Error loading vmlinux BTF: %d\n", err); + obj->btf_vmlinux = NULL; + return err; + } + return 0; +} + +static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj) +{ + struct btf *kern_btf = obj->btf; + bool btf_mandatory, sanitize; + int err = 0; + + if (!obj->btf) + return 0; + + if (!kernel_supports(FEAT_BTF)) { + if (kernel_needs_btf(obj)) { + err = -EOPNOTSUPP; + goto report; + } + pr_debug("Kernel doesn't support BTF, skipping uploading it.\n"); + return 0; + } + + sanitize = btf_needs_sanitization(obj); + if (sanitize) { + const void *raw_data; + __u32 sz; + + /* clone BTF to sanitize a copy and leave the original intact */ + raw_data = btf__get_raw_data(obj->btf, &sz); + kern_btf = btf__new(raw_data, sz); + if (IS_ERR(kern_btf)) + return PTR_ERR(kern_btf); + + /* enforce 8-byte pointers for BPF-targeted BTFs */ + btf__set_pointer_size(obj->btf, 8); + bpf_object__sanitize_btf(obj, kern_btf); + } + + err = btf__load(kern_btf); + if (sanitize) { + if (!err) { + /* move fd to libbpf's BTF */ + btf__set_fd(obj->btf, btf__fd(kern_btf)); + btf__set_fd(kern_btf, -1); + } + btf__free(kern_btf); + } +report: + if (err) { + btf_mandatory = kernel_needs_btf(obj); + pr_warn("Error loading .BTF into kernel: %d. %s\n", err, + btf_mandatory ? "BTF is mandatory, can't proceed." + : "BTF is optional, ignoring."); + if (!btf_mandatory) + err = 0; + } + return err; +} + +static const char *elf_sym_str(const struct bpf_object *obj, size_t off) +{ + const char *name; + + name = elf_strptr(obj->efile.elf, obj->efile.strtabidx, off); + if (!name) { + pr_warn("elf: failed to get section name string at offset %zu from %s: %s\n", + off, obj->path, elf_errmsg(-1)); + return NULL; + } + + return name; +} + +static const char *elf_sec_str(const struct bpf_object *obj, size_t off) +{ + const char *name; + + name = elf_strptr(obj->efile.elf, obj->efile.shstrndx, off); + if (!name) { + pr_warn("elf: failed to get section name string at offset %zu from %s: %s\n", + off, obj->path, elf_errmsg(-1)); + return NULL; + } + + return name; +} + +static Elf_Scn *elf_sec_by_idx(const struct bpf_object *obj, size_t idx) +{ + Elf_Scn *scn; + + scn = elf_getscn(obj->efile.elf, idx); + if (!scn) { + pr_warn("elf: failed to get section(%zu) from %s: %s\n", + idx, obj->path, elf_errmsg(-1)); + return NULL; + } + return scn; +} + +static Elf_Scn *elf_sec_by_name(const struct bpf_object *obj, const char *name) +{ + Elf_Scn *scn = NULL; + Elf *elf = obj->efile.elf; + const char *sec_name; + + while ((scn = elf_nextscn(elf, scn)) != NULL) { + sec_name = elf_sec_name(obj, scn); + if (!sec_name) + return NULL; + + if (strcmp(sec_name, name) != 0) + continue; + + return scn; + } + return NULL; +} + +static int elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn, GElf_Shdr *hdr) +{ + if (!scn) + return -EINVAL; + + if (gelf_getshdr(scn, hdr) != hdr) { + pr_warn("elf: failed to get section(%zu) header from %s: %s\n", + elf_ndxscn(scn), obj->path, elf_errmsg(-1)); + return -EINVAL; + } + + return 0; +} + +static const char *elf_sec_name(const struct bpf_object *obj, Elf_Scn *scn) +{ + const char *name; + GElf_Shdr sh; + + if (!scn) + return NULL; + + if (elf_sec_hdr(obj, scn, &sh)) + return NULL; + + name = elf_sec_str(obj, sh.sh_name); + if (!name) { + pr_warn("elf: failed to get section(%zu) name from %s: %s\n", + elf_ndxscn(scn), obj->path, elf_errmsg(-1)); + return NULL; + } + + return name; +} + +static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn) +{ + Elf_Data *data; + + if (!scn) + return NULL; + + data = elf_getdata(scn, 0); + if (!data) { + pr_warn("elf: failed to get section(%zu) %s data from %s: %s\n", + elf_ndxscn(scn), elf_sec_name(obj, scn) ?: "<?>", + obj->path, elf_errmsg(-1)); + return NULL; + } + + return data; +} + +static int elf_sym_by_sec_off(const struct bpf_object *obj, size_t sec_idx, + size_t off, __u32 sym_type, GElf_Sym *sym) +{ + Elf_Data *symbols = obj->efile.symbols; + size_t n = symbols->d_size / sizeof(GElf_Sym); + int i; + + for (i = 0; i < n; i++) { + if (!gelf_getsym(symbols, i, sym)) + continue; + if (sym->st_shndx != sec_idx || sym->st_value != off) + continue; + if (GELF_ST_TYPE(sym->st_info) != sym_type) + continue; + return 0; + } + + return -ENOENT; +} + +static bool is_sec_name_dwarf(const char *name) +{ + /* approximation, but the actual list is too long */ + return strncmp(name, ".debug_", sizeof(".debug_") - 1) == 0; +} + +static bool ignore_elf_section(GElf_Shdr *hdr, const char *name) +{ + /* no special handling of .strtab */ + if (hdr->sh_type == SHT_STRTAB) + return true; + + /* ignore .llvm_addrsig section as well */ + if (hdr->sh_type == 0x6FFF4C03 /* SHT_LLVM_ADDRSIG */) + return true; + + /* no subprograms will lead to an empty .text section, ignore it */ + if (hdr->sh_type == SHT_PROGBITS && hdr->sh_size == 0 && + strcmp(name, ".text") == 0) + return true; + + /* DWARF sections */ + if (is_sec_name_dwarf(name)) + return true; + + if (strncmp(name, ".rel", sizeof(".rel") - 1) == 0) { + name += sizeof(".rel") - 1; + /* DWARF section relocations */ + if (is_sec_name_dwarf(name)) + return true; + + /* .BTF and .BTF.ext don't need relocations */ + if (strcmp(name, BTF_ELF_SEC) == 0 || + strcmp(name, BTF_EXT_ELF_SEC) == 0) + return true; + } + + return false; +} + +static int cmp_progs(const void *_a, const void *_b) +{ + const struct bpf_program *a = _a; + const struct bpf_program *b = _b; + + if (a->sec_idx != b->sec_idx) + return a->sec_idx < b->sec_idx ? -1 : 1; + + /* sec_insn_off can't be the same within the section */ + return a->sec_insn_off < b->sec_insn_off ? -1 : 1; +} + +static int bpf_object__elf_collect(struct bpf_object *obj) +{ + Elf *elf = obj->efile.elf; + Elf_Data *btf_ext_data = NULL; + Elf_Data *btf_data = NULL; + int idx = 0, err = 0; + const char *name; + Elf_Data *data; + Elf_Scn *scn; + GElf_Shdr sh; + + /* a bunch of ELF parsing functionality depends on processing symbols, + * so do the first pass and find the symbol table + */ + scn = NULL; + while ((scn = elf_nextscn(elf, scn)) != NULL) { + if (elf_sec_hdr(obj, scn, &sh)) + return -LIBBPF_ERRNO__FORMAT; + + if (sh.sh_type == SHT_SYMTAB) { + if (obj->efile.symbols) { + pr_warn("elf: multiple symbol tables in %s\n", obj->path); + return -LIBBPF_ERRNO__FORMAT; + } + + data = elf_sec_data(obj, scn); + if (!data) + return -LIBBPF_ERRNO__FORMAT; + + obj->efile.symbols = data; + obj->efile.symbols_shndx = elf_ndxscn(scn); + obj->efile.strtabidx = sh.sh_link; + } + } + + scn = NULL; + while ((scn = elf_nextscn(elf, scn)) != NULL) { + idx++; + + if (elf_sec_hdr(obj, scn, &sh)) + return -LIBBPF_ERRNO__FORMAT; + + name = elf_sec_str(obj, sh.sh_name); + if (!name) + return -LIBBPF_ERRNO__FORMAT; + + if (ignore_elf_section(&sh, name)) + continue; + + data = elf_sec_data(obj, scn); + if (!data) + return -LIBBPF_ERRNO__FORMAT; + + pr_debug("elf: section(%d) %s, size %ld, link %d, flags %lx, type=%d\n", + idx, name, (unsigned long)data->d_size, + (int)sh.sh_link, (unsigned long)sh.sh_flags, + (int)sh.sh_type); + + if (strcmp(name, "license") == 0) { + err = bpf_object__init_license(obj, data->d_buf, data->d_size); + if (err) + return err; + } else if (strcmp(name, "version") == 0) { + err = bpf_object__init_kversion(obj, data->d_buf, data->d_size); + if (err) + return err; + } else if (strcmp(name, "maps") == 0) { + obj->efile.maps_shndx = idx; + } else if (strcmp(name, MAPS_ELF_SEC) == 0) { + obj->efile.btf_maps_shndx = idx; + } else if (strcmp(name, BTF_ELF_SEC) == 0) { + btf_data = data; + } else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) { + btf_ext_data = data; + } else if (sh.sh_type == SHT_SYMTAB) { + /* already processed during the first pass above */ + } else if (sh.sh_type == SHT_PROGBITS && data->d_size > 0) { + if (sh.sh_flags & SHF_EXECINSTR) { + if (strcmp(name, ".text") == 0) + obj->efile.text_shndx = idx; + err = bpf_object__add_programs(obj, data, name, idx); + if (err) + return err; + } else if (strcmp(name, DATA_SEC) == 0) { + obj->efile.data = data; + obj->efile.data_shndx = idx; + } else if (strcmp(name, RODATA_SEC) == 0) { + obj->efile.rodata = data; + obj->efile.rodata_shndx = idx; + } else if (strcmp(name, STRUCT_OPS_SEC) == 0) { + obj->efile.st_ops_data = data; + obj->efile.st_ops_shndx = idx; + } else { + pr_info("elf: skipping unrecognized data section(%d) %s\n", + idx, name); + } + } else if (sh.sh_type == SHT_REL) { + int nr_sects = obj->efile.nr_reloc_sects; + void *sects = obj->efile.reloc_sects; + int sec = sh.sh_info; /* points to other section */ + + /* Only do relo for section with exec instructions */ + if (!section_have_execinstr(obj, sec) && + strcmp(name, ".rel" STRUCT_OPS_SEC) && + strcmp(name, ".rel" MAPS_ELF_SEC)) { + pr_info("elf: skipping relo section(%d) %s for section(%d) %s\n", + idx, name, sec, + elf_sec_name(obj, elf_sec_by_idx(obj, sec)) ?: "<?>"); + continue; + } + + sects = libbpf_reallocarray(sects, nr_sects + 1, + sizeof(*obj->efile.reloc_sects)); + if (!sects) + return -ENOMEM; + + obj->efile.reloc_sects = sects; + obj->efile.nr_reloc_sects++; + + obj->efile.reloc_sects[nr_sects].shdr = sh; + obj->efile.reloc_sects[nr_sects].data = data; + } else if (sh.sh_type == SHT_NOBITS && strcmp(name, BSS_SEC) == 0) { + obj->efile.bss = data; + obj->efile.bss_shndx = idx; + } else { + pr_info("elf: skipping section(%d) %s (size %zu)\n", idx, name, + (size_t)sh.sh_size); + } + } + + if (!obj->efile.strtabidx || obj->efile.strtabidx > idx) { + pr_warn("elf: symbol strings section missing or invalid in %s\n", obj->path); + return -LIBBPF_ERRNO__FORMAT; + } + + /* sort BPF programs by section name and in-section instruction offset + * for faster search */ + qsort(obj->programs, obj->nr_programs, sizeof(*obj->programs), cmp_progs); + + return bpf_object__init_btf(obj, btf_data, btf_ext_data); +} + +static bool sym_is_extern(const GElf_Sym *sym) +{ + int bind = GELF_ST_BIND(sym->st_info); + /* externs are symbols w/ type=NOTYPE, bind=GLOBAL|WEAK, section=UND */ + return sym->st_shndx == SHN_UNDEF && + (bind == STB_GLOBAL || bind == STB_WEAK) && + GELF_ST_TYPE(sym->st_info) == STT_NOTYPE; +} + +static int find_extern_btf_id(const struct btf *btf, const char *ext_name) +{ + const struct btf_type *t; + const char *var_name; + int i, n; + + if (!btf) + return -ESRCH; + + n = btf__get_nr_types(btf); + for (i = 1; i <= n; i++) { + t = btf__type_by_id(btf, i); + + if (!btf_is_var(t)) + continue; + + var_name = btf__name_by_offset(btf, t->name_off); + if (strcmp(var_name, ext_name)) + continue; + + if (btf_var(t)->linkage != BTF_VAR_GLOBAL_EXTERN) + return -EINVAL; + + return i; + } + + return -ENOENT; +} + +static int find_extern_sec_btf_id(struct btf *btf, int ext_btf_id) { + const struct btf_var_secinfo *vs; + const struct btf_type *t; + int i, j, n; + + if (!btf) + return -ESRCH; + + n = btf__get_nr_types(btf); + for (i = 1; i <= n; i++) { + t = btf__type_by_id(btf, i); + + if (!btf_is_datasec(t)) + continue; + + vs = btf_var_secinfos(t); + for (j = 0; j < btf_vlen(t); j++, vs++) { + if (vs->type == ext_btf_id) + return i; + } + } + + return -ENOENT; +} + +static enum kcfg_type find_kcfg_type(const struct btf *btf, int id, + bool *is_signed) +{ + const struct btf_type *t; + const char *name; + + t = skip_mods_and_typedefs(btf, id, NULL); + name = btf__name_by_offset(btf, t->name_off); + + if (is_signed) + *is_signed = false; + switch (btf_kind(t)) { + case BTF_KIND_INT: { + int enc = btf_int_encoding(t); + + if (enc & BTF_INT_BOOL) + return t->size == 1 ? KCFG_BOOL : KCFG_UNKNOWN; + if (is_signed) + *is_signed = enc & BTF_INT_SIGNED; + if (t->size == 1) + return KCFG_CHAR; + if (t->size < 1 || t->size > 8 || (t->size & (t->size - 1))) + return KCFG_UNKNOWN; + return KCFG_INT; + } + case BTF_KIND_ENUM: + if (t->size != 4) + return KCFG_UNKNOWN; + if (strcmp(name, "libbpf_tristate")) + return KCFG_UNKNOWN; + return KCFG_TRISTATE; + case BTF_KIND_ARRAY: + if (btf_array(t)->nelems == 0) + return KCFG_UNKNOWN; + if (find_kcfg_type(btf, btf_array(t)->type, NULL) != KCFG_CHAR) + return KCFG_UNKNOWN; + return KCFG_CHAR_ARR; + default: + return KCFG_UNKNOWN; + } +} + +static int cmp_externs(const void *_a, const void *_b) +{ + const struct extern_desc *a = _a; + const struct extern_desc *b = _b; + + if (a->type != b->type) + return a->type < b->type ? -1 : 1; + + if (a->type == EXT_KCFG) { + /* descending order by alignment requirements */ + if (a->kcfg.align != b->kcfg.align) + return a->kcfg.align > b->kcfg.align ? -1 : 1; + /* ascending order by size, within same alignment class */ + if (a->kcfg.sz != b->kcfg.sz) + return a->kcfg.sz < b->kcfg.sz ? -1 : 1; + } + + /* resolve ties by name */ + return strcmp(a->name, b->name); +} + +static int find_int_btf_id(const struct btf *btf) +{ + const struct btf_type *t; + int i, n; + + n = btf__get_nr_types(btf); + for (i = 1; i <= n; i++) { + t = btf__type_by_id(btf, i); + + if (btf_is_int(t) && btf_int_bits(t) == 32) + return i; + } + + return 0; +} + +static int bpf_object__collect_externs(struct bpf_object *obj) +{ + struct btf_type *sec, *kcfg_sec = NULL, *ksym_sec = NULL; + const struct btf_type *t; + struct extern_desc *ext; + int i, n, off; + const char *ext_name, *sec_name; + Elf_Scn *scn; + GElf_Shdr sh; + + if (!obj->efile.symbols) + return 0; + + scn = elf_sec_by_idx(obj, obj->efile.symbols_shndx); + if (elf_sec_hdr(obj, scn, &sh)) + return -LIBBPF_ERRNO__FORMAT; + + n = sh.sh_size / sh.sh_entsize; + pr_debug("looking for externs among %d symbols...\n", n); + + for (i = 0; i < n; i++) { + GElf_Sym sym; + + if (!gelf_getsym(obj->efile.symbols, i, &sym)) + return -LIBBPF_ERRNO__FORMAT; + if (!sym_is_extern(&sym)) + continue; + ext_name = elf_sym_str(obj, sym.st_name); + if (!ext_name || !ext_name[0]) + continue; + + ext = obj->externs; + ext = libbpf_reallocarray(ext, obj->nr_extern + 1, sizeof(*ext)); + if (!ext) + return -ENOMEM; + obj->externs = ext; + ext = &ext[obj->nr_extern]; + memset(ext, 0, sizeof(*ext)); + obj->nr_extern++; + + ext->btf_id = find_extern_btf_id(obj->btf, ext_name); + if (ext->btf_id <= 0) { + pr_warn("failed to find BTF for extern '%s': %d\n", + ext_name, ext->btf_id); + return ext->btf_id; + } + t = btf__type_by_id(obj->btf, ext->btf_id); + ext->name = btf__name_by_offset(obj->btf, t->name_off); + ext->sym_idx = i; + ext->is_weak = GELF_ST_BIND(sym.st_info) == STB_WEAK; + + ext->sec_btf_id = find_extern_sec_btf_id(obj->btf, ext->btf_id); + if (ext->sec_btf_id <= 0) { + pr_warn("failed to find BTF for extern '%s' [%d] section: %d\n", + ext_name, ext->btf_id, ext->sec_btf_id); + return ext->sec_btf_id; + } + sec = (void *)btf__type_by_id(obj->btf, ext->sec_btf_id); + sec_name = btf__name_by_offset(obj->btf, sec->name_off); + + if (strcmp(sec_name, KCONFIG_SEC) == 0) { + kcfg_sec = sec; + ext->type = EXT_KCFG; + ext->kcfg.sz = btf__resolve_size(obj->btf, t->type); + if (ext->kcfg.sz <= 0) { + pr_warn("failed to resolve size of extern (kcfg) '%s': %d\n", + ext_name, ext->kcfg.sz); + return ext->kcfg.sz; + } + ext->kcfg.align = btf__align_of(obj->btf, t->type); + if (ext->kcfg.align <= 0) { + pr_warn("failed to determine alignment of extern (kcfg) '%s': %d\n", + ext_name, ext->kcfg.align); + return -EINVAL; + } + ext->kcfg.type = find_kcfg_type(obj->btf, t->type, + &ext->kcfg.is_signed); + if (ext->kcfg.type == KCFG_UNKNOWN) { + pr_warn("extern (kcfg) '%s' type is unsupported\n", ext_name); + return -ENOTSUP; + } + } else if (strcmp(sec_name, KSYMS_SEC) == 0) { + ksym_sec = sec; + ext->type = EXT_KSYM; + skip_mods_and_typedefs(obj->btf, t->type, + &ext->ksym.type_id); + } else { + pr_warn("unrecognized extern section '%s'\n", sec_name); + return -ENOTSUP; + } + } + pr_debug("collected %d externs total\n", obj->nr_extern); + + if (!obj->nr_extern) + return 0; + + /* sort externs by type, for kcfg ones also by (align, size, name) */ + qsort(obj->externs, obj->nr_extern, sizeof(*ext), cmp_externs); + + /* for .ksyms section, we need to turn all externs into allocated + * variables in BTF to pass kernel verification; we do this by + * pretending that each extern is a 8-byte variable + */ + if (ksym_sec) { + /* find existing 4-byte integer type in BTF to use for fake + * extern variables in DATASEC + */ + int int_btf_id = find_int_btf_id(obj->btf); + + for (i = 0; i < obj->nr_extern; i++) { + ext = &obj->externs[i]; + if (ext->type != EXT_KSYM) + continue; + pr_debug("extern (ksym) #%d: symbol %d, name %s\n", + i, ext->sym_idx, ext->name); + } + + sec = ksym_sec; + n = btf_vlen(sec); + for (i = 0, off = 0; i < n; i++, off += sizeof(int)) { + struct btf_var_secinfo *vs = btf_var_secinfos(sec) + i; + struct btf_type *vt; + + vt = (void *)btf__type_by_id(obj->btf, vs->type); + ext_name = btf__name_by_offset(obj->btf, vt->name_off); + ext = find_extern_by_name(obj, ext_name); + if (!ext) { + pr_warn("failed to find extern definition for BTF var '%s'\n", + ext_name); + return -ESRCH; + } + btf_var(vt)->linkage = BTF_VAR_GLOBAL_ALLOCATED; + vt->type = int_btf_id; + vs->offset = off; + vs->size = sizeof(int); + } + sec->size = off; + } + + if (kcfg_sec) { + sec = kcfg_sec; + /* for kcfg externs calculate their offsets within a .kconfig map */ + off = 0; + for (i = 0; i < obj->nr_extern; i++) { + ext = &obj->externs[i]; + if (ext->type != EXT_KCFG) + continue; + + ext->kcfg.data_off = roundup(off, ext->kcfg.align); + off = ext->kcfg.data_off + ext->kcfg.sz; + pr_debug("extern (kcfg) #%d: symbol %d, off %u, name %s\n", + i, ext->sym_idx, ext->kcfg.data_off, ext->name); + } + sec->size = off; + n = btf_vlen(sec); + for (i = 0; i < n; i++) { + struct btf_var_secinfo *vs = btf_var_secinfos(sec) + i; + + t = btf__type_by_id(obj->btf, vs->type); + ext_name = btf__name_by_offset(obj->btf, t->name_off); + ext = find_extern_by_name(obj, ext_name); + if (!ext) { + pr_warn("failed to find extern definition for BTF var '%s'\n", + ext_name); + return -ESRCH; + } + btf_var(t)->linkage = BTF_VAR_GLOBAL_ALLOCATED; + vs->offset = ext->kcfg.data_off; + } + } + return 0; +} + +struct bpf_program * +bpf_object__find_program_by_title(const struct bpf_object *obj, + const char *title) +{ + struct bpf_program *pos; + + bpf_object__for_each_program(pos, obj) { + if (pos->sec_name && !strcmp(pos->sec_name, title)) + return pos; + } + return NULL; +} + +static bool prog_is_subprog(const struct bpf_object *obj, + const struct bpf_program *prog) +{ + /* For legacy reasons, libbpf supports an entry-point BPF programs + * without SEC() attribute, i.e., those in the .text section. But if + * there are 2 or more such programs in the .text section, they all + * must be subprograms called from entry-point BPF programs in + * designated SEC()'tions, otherwise there is no way to distinguish + * which of those programs should be loaded vs which are a subprogram. + * Similarly, if there is a function/program in .text and at least one + * other BPF program with custom SEC() attribute, then we just assume + * .text programs are subprograms (even if they are not called from + * other programs), because libbpf never explicitly supported mixing + * SEC()-designated BPF programs and .text entry-point BPF programs. + */ + return prog->sec_idx == obj->efile.text_shndx && obj->nr_programs > 1; +} + +struct bpf_program * +bpf_object__find_program_by_name(const struct bpf_object *obj, + const char *name) +{ + struct bpf_program *prog; + + bpf_object__for_each_program(prog, obj) { + if (prog_is_subprog(obj, prog)) + continue; + if (!strcmp(prog->name, name)) + return prog; + } + return NULL; +} + +static bool bpf_object__shndx_is_data(const struct bpf_object *obj, + int shndx) +{ + return shndx == obj->efile.data_shndx || + shndx == obj->efile.bss_shndx || + shndx == obj->efile.rodata_shndx; +} + +static bool bpf_object__shndx_is_maps(const struct bpf_object *obj, + int shndx) +{ + return shndx == obj->efile.maps_shndx || + shndx == obj->efile.btf_maps_shndx; +} + +static enum libbpf_map_type +bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx) +{ + if (shndx == obj->efile.data_shndx) + return LIBBPF_MAP_DATA; + else if (shndx == obj->efile.bss_shndx) + return LIBBPF_MAP_BSS; + else if (shndx == obj->efile.rodata_shndx) + return LIBBPF_MAP_RODATA; + else if (shndx == obj->efile.symbols_shndx) + return LIBBPF_MAP_KCONFIG; + else + return LIBBPF_MAP_UNSPEC; +} + +static int bpf_program__record_reloc(struct bpf_program *prog, + struct reloc_desc *reloc_desc, + __u32 insn_idx, const char *sym_name, + const GElf_Sym *sym, const GElf_Rel *rel) +{ + struct bpf_insn *insn = &prog->insns[insn_idx]; + size_t map_idx, nr_maps = prog->obj->nr_maps; + struct bpf_object *obj = prog->obj; + __u32 shdr_idx = sym->st_shndx; + enum libbpf_map_type type; + const char *sym_sec_name; + struct bpf_map *map; + + reloc_desc->processed = false; + + /* sub-program call relocation */ + if (insn->code == (BPF_JMP | BPF_CALL)) { + if (insn->src_reg != BPF_PSEUDO_CALL) { + pr_warn("prog '%s': incorrect bpf_call opcode\n", prog->name); + return -LIBBPF_ERRNO__RELOC; + } + /* text_shndx can be 0, if no default "main" program exists */ + if (!shdr_idx || shdr_idx != obj->efile.text_shndx) { + sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx)); + pr_warn("prog '%s': bad call relo against '%s' in section '%s'\n", + prog->name, sym_name, sym_sec_name); + return -LIBBPF_ERRNO__RELOC; + } + if (sym->st_value % BPF_INSN_SZ) { + pr_warn("prog '%s': bad call relo against '%s' at offset %zu\n", + prog->name, sym_name, (size_t)sym->st_value); + return -LIBBPF_ERRNO__RELOC; + } + reloc_desc->type = RELO_CALL; + reloc_desc->insn_idx = insn_idx; + reloc_desc->sym_off = sym->st_value; + return 0; + } + + if (insn->code != (BPF_LD | BPF_IMM | BPF_DW)) { + pr_warn("prog '%s': invalid relo against '%s' for insns[%d].code 0x%x\n", + prog->name, sym_name, insn_idx, insn->code); + return -LIBBPF_ERRNO__RELOC; + } + + if (sym_is_extern(sym)) { + int sym_idx = GELF_R_SYM(rel->r_info); + int i, n = obj->nr_extern; + struct extern_desc *ext; + + for (i = 0; i < n; i++) { + ext = &obj->externs[i]; + if (ext->sym_idx == sym_idx) + break; + } + if (i >= n) { + pr_warn("prog '%s': extern relo failed to find extern for '%s' (%d)\n", + prog->name, sym_name, sym_idx); + return -LIBBPF_ERRNO__RELOC; + } + pr_debug("prog '%s': found extern #%d '%s' (sym %d) for insn #%u\n", + prog->name, i, ext->name, ext->sym_idx, insn_idx); + reloc_desc->type = RELO_EXTERN; + reloc_desc->insn_idx = insn_idx; + reloc_desc->sym_off = i; /* sym_off stores extern index */ + return 0; + } + + if (!shdr_idx || shdr_idx >= SHN_LORESERVE) { + pr_warn("prog '%s': invalid relo against '%s' in special section 0x%x; forgot to initialize global var?..\n", + prog->name, sym_name, shdr_idx); + return -LIBBPF_ERRNO__RELOC; + } + + type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx); + sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx)); + + /* generic map reference relocation */ + if (type == LIBBPF_MAP_UNSPEC) { + if (!bpf_object__shndx_is_maps(obj, shdr_idx)) { + pr_warn("prog '%s': bad map relo against '%s' in section '%s'\n", + prog->name, sym_name, sym_sec_name); + return -LIBBPF_ERRNO__RELOC; + } + for (map_idx = 0; map_idx < nr_maps; map_idx++) { + map = &obj->maps[map_idx]; + if (map->libbpf_type != type || + map->sec_idx != sym->st_shndx || + map->sec_offset != sym->st_value) + continue; + pr_debug("prog '%s': found map %zd (%s, sec %d, off %zu) for insn #%u\n", + prog->name, map_idx, map->name, map->sec_idx, + map->sec_offset, insn_idx); + break; + } + if (map_idx >= nr_maps) { + pr_warn("prog '%s': map relo failed to find map for section '%s', off %zu\n", + prog->name, sym_sec_name, (size_t)sym->st_value); + return -LIBBPF_ERRNO__RELOC; + } + reloc_desc->type = RELO_LD64; + reloc_desc->insn_idx = insn_idx; + reloc_desc->map_idx = map_idx; + reloc_desc->sym_off = 0; /* sym->st_value determines map_idx */ + return 0; + } + + /* global data map relocation */ + if (!bpf_object__shndx_is_data(obj, shdr_idx)) { + pr_warn("prog '%s': bad data relo against section '%s'\n", + prog->name, sym_sec_name); + return -LIBBPF_ERRNO__RELOC; + } + for (map_idx = 0; map_idx < nr_maps; map_idx++) { + map = &obj->maps[map_idx]; + if (map->libbpf_type != type) + continue; + pr_debug("prog '%s': found data map %zd (%s, sec %d, off %zu) for insn %u\n", + prog->name, map_idx, map->name, map->sec_idx, + map->sec_offset, insn_idx); + break; + } + if (map_idx >= nr_maps) { + pr_warn("prog '%s': data relo failed to find map for section '%s'\n", + prog->name, sym_sec_name); + return -LIBBPF_ERRNO__RELOC; + } + + reloc_desc->type = RELO_DATA; + reloc_desc->insn_idx = insn_idx; + reloc_desc->map_idx = map_idx; + reloc_desc->sym_off = sym->st_value; + return 0; +} + +static bool prog_contains_insn(const struct bpf_program *prog, size_t insn_idx) +{ + return insn_idx >= prog->sec_insn_off && + insn_idx < prog->sec_insn_off + prog->sec_insn_cnt; +} + +static struct bpf_program *find_prog_by_sec_insn(const struct bpf_object *obj, + size_t sec_idx, size_t insn_idx) +{ + int l = 0, r = obj->nr_programs - 1, m; + struct bpf_program *prog; + + if (!obj->nr_programs) + return NULL; + + while (l < r) { + m = l + (r - l + 1) / 2; + prog = &obj->programs[m]; + + if (prog->sec_idx < sec_idx || + (prog->sec_idx == sec_idx && prog->sec_insn_off <= insn_idx)) + l = m; + else + r = m - 1; + } + /* matching program could be at index l, but it still might be the + * wrong one, so we need to double check conditions for the last time + */ + prog = &obj->programs[l]; + if (prog->sec_idx == sec_idx && prog_contains_insn(prog, insn_idx)) + return prog; + return NULL; +} + +static int +bpf_object__collect_prog_relos(struct bpf_object *obj, GElf_Shdr *shdr, Elf_Data *data) +{ + Elf_Data *symbols = obj->efile.symbols; + const char *relo_sec_name, *sec_name; + size_t sec_idx = shdr->sh_info; + struct bpf_program *prog; + struct reloc_desc *relos; + int err, i, nrels; + const char *sym_name; + __u32 insn_idx; + GElf_Sym sym; + GElf_Rel rel; + + relo_sec_name = elf_sec_str(obj, shdr->sh_name); + sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx)); + if (!relo_sec_name || !sec_name) + return -EINVAL; + + pr_debug("sec '%s': collecting relocation for section(%zu) '%s'\n", + relo_sec_name, sec_idx, sec_name); + nrels = shdr->sh_size / shdr->sh_entsize; + + for (i = 0; i < nrels; i++) { + if (!gelf_getrel(data, i, &rel)) { + pr_warn("sec '%s': failed to get relo #%d\n", relo_sec_name, i); + return -LIBBPF_ERRNO__FORMAT; + } + if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) { + pr_warn("sec '%s': symbol 0x%zx not found for relo #%d\n", + relo_sec_name, (size_t)GELF_R_SYM(rel.r_info), i); + return -LIBBPF_ERRNO__FORMAT; + } + if (rel.r_offset % BPF_INSN_SZ) { + pr_warn("sec '%s': invalid offset 0x%zx for relo #%d\n", + relo_sec_name, (size_t)GELF_R_SYM(rel.r_info), i); + return -LIBBPF_ERRNO__FORMAT; + } + + insn_idx = rel.r_offset / BPF_INSN_SZ; + /* relocations against static functions are recorded as + * relocations against the section that contains a function; + * in such case, symbol will be STT_SECTION and sym.st_name + * will point to empty string (0), so fetch section name + * instead + */ + if (GELF_ST_TYPE(sym.st_info) == STT_SECTION && sym.st_name == 0) + sym_name = elf_sec_name(obj, elf_sec_by_idx(obj, sym.st_shndx)); + else + sym_name = elf_sym_str(obj, sym.st_name); + sym_name = sym_name ?: "<?"; + + pr_debug("sec '%s': relo #%d: insn #%u against '%s'\n", + relo_sec_name, i, insn_idx, sym_name); + + prog = find_prog_by_sec_insn(obj, sec_idx, insn_idx); + if (!prog) { + pr_warn("sec '%s': relo #%d: program not found in section '%s' for insn #%u\n", + relo_sec_name, i, sec_name, insn_idx); + return -LIBBPF_ERRNO__RELOC; + } + + relos = libbpf_reallocarray(prog->reloc_desc, + prog->nr_reloc + 1, sizeof(*relos)); + if (!relos) + return -ENOMEM; + prog->reloc_desc = relos; + + /* adjust insn_idx to local BPF program frame of reference */ + insn_idx -= prog->sec_insn_off; + err = bpf_program__record_reloc(prog, &relos[prog->nr_reloc], + insn_idx, sym_name, &sym, &rel); + if (err) + return err; + + prog->nr_reloc++; + } + return 0; +} + +static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map) +{ + struct bpf_map_def *def = &map->def; + __u32 key_type_id = 0, value_type_id = 0; + int ret; + + /* if it's BTF-defined map, we don't need to search for type IDs. + * For struct_ops map, it does not need btf_key_type_id and + * btf_value_type_id. + */ + if (map->sec_idx == obj->efile.btf_maps_shndx || + bpf_map__is_struct_ops(map)) + return 0; + + if (!bpf_map__is_internal(map)) { + ret = btf__get_map_kv_tids(obj->btf, map->name, def->key_size, + def->value_size, &key_type_id, + &value_type_id); + } else { + /* + * LLVM annotates global data differently in BTF, that is, + * only as '.data', '.bss' or '.rodata'. + */ + ret = btf__find_by_name(obj->btf, + libbpf_type_to_btf_name[map->libbpf_type]); + } + if (ret < 0) + return ret; + + map->btf_key_type_id = key_type_id; + map->btf_value_type_id = bpf_map__is_internal(map) ? + ret : value_type_id; + return 0; +} + +static int bpf_get_map_info_from_fdinfo(int fd, struct bpf_map_info *info) +{ + char file[PATH_MAX], buff[4096]; + FILE *fp; + __u32 val; + int err; + + snprintf(file, sizeof(file), "/proc/%d/fdinfo/%d", getpid(), fd); + memset(info, 0, sizeof(*info)); + + fp = fopen(file, "r"); + if (!fp) { + err = -errno; + pr_warn("failed to open %s: %d. No procfs support?\n", file, + err); + return err; + } + + while (fgets(buff, sizeof(buff), fp)) { + if (sscanf(buff, "map_type:\t%u", &val) == 1) + info->type = val; + else if (sscanf(buff, "key_size:\t%u", &val) == 1) + info->key_size = val; + else if (sscanf(buff, "value_size:\t%u", &val) == 1) + info->value_size = val; + else if (sscanf(buff, "max_entries:\t%u", &val) == 1) + info->max_entries = val; + else if (sscanf(buff, "map_flags:\t%i", &val) == 1) + info->map_flags = val; + } + + fclose(fp); + + return 0; +} + +int bpf_map__reuse_fd(struct bpf_map *map, int fd) +{ + struct bpf_map_info info = {}; + __u32 len = sizeof(info), name_len; + int new_fd, err; + char *new_name; + + err = bpf_obj_get_info_by_fd(fd, &info, &len); + if (err && errno == EINVAL) + err = bpf_get_map_info_from_fdinfo(fd, &info); + if (err) + return err; + + name_len = strlen(info.name); + if (name_len == BPF_OBJ_NAME_LEN - 1 && strncmp(map->name, info.name, name_len) == 0) + new_name = strdup(map->name); + else + new_name = strdup(info.name); + + if (!new_name) + return -errno; + + new_fd = open("/", O_RDONLY | O_CLOEXEC); + if (new_fd < 0) { + err = -errno; + goto err_free_new_name; + } + + new_fd = dup3(fd, new_fd, O_CLOEXEC); + if (new_fd < 0) { + err = -errno; + goto err_close_new_fd; + } + + err = zclose(map->fd); + if (err) { + err = -errno; + goto err_close_new_fd; + } + free(map->name); + + map->fd = new_fd; + map->name = new_name; + map->def.type = info.type; + map->def.key_size = info.key_size; + map->def.value_size = info.value_size; + map->def.max_entries = info.max_entries; + map->def.map_flags = info.map_flags; + map->btf_key_type_id = info.btf_key_type_id; + map->btf_value_type_id = info.btf_value_type_id; + map->reused = true; + + return 0; + +err_close_new_fd: + close(new_fd); +err_free_new_name: + free(new_name); + return err; +} + +__u32 bpf_map__max_entries(const struct bpf_map *map) +{ + return map->def.max_entries; +} + +int bpf_map__set_max_entries(struct bpf_map *map, __u32 max_entries) +{ + if (map->fd >= 0) + return -EBUSY; + map->def.max_entries = max_entries; + return 0; +} + +int bpf_map__resize(struct bpf_map *map, __u32 max_entries) +{ + if (!map || !max_entries) + return -EINVAL; + + return bpf_map__set_max_entries(map, max_entries); +} + +static int +bpf_object__probe_loading(struct bpf_object *obj) +{ + struct bpf_load_program_attr attr; + char *cp, errmsg[STRERR_BUFSIZE]; + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + int ret; + + /* make sure basic loading works */ + + memset(&attr, 0, sizeof(attr)); + attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER; + attr.insns = insns; + attr.insns_cnt = ARRAY_SIZE(insns); + attr.license = "GPL"; + + ret = bpf_load_program_xattr(&attr, NULL, 0); + if (ret < 0) { + ret = errno; + cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg)); + pr_warn("Error in %s():%s(%d). Couldn't load trivial BPF " + "program. Make sure your kernel supports BPF " + "(CONFIG_BPF_SYSCALL=y) and/or that RLIMIT_MEMLOCK is " + "set to big enough value.\n", __func__, cp, ret); + return -ret; + } + close(ret); + + return 0; +} + +static int probe_fd(int fd) +{ + if (fd >= 0) + close(fd); + return fd >= 0; +} + +static int probe_kern_prog_name(void) +{ + struct bpf_load_program_attr attr; + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + int ret; + + /* make sure loading with name works */ + + memset(&attr, 0, sizeof(attr)); + attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER; + attr.insns = insns; + attr.insns_cnt = ARRAY_SIZE(insns); + attr.license = "GPL"; + attr.name = "test"; + ret = bpf_load_program_xattr(&attr, NULL, 0); + return probe_fd(ret); +} + +static int probe_kern_global_data(void) +{ + struct bpf_load_program_attr prg_attr; + struct bpf_create_map_attr map_attr; + char *cp, errmsg[STRERR_BUFSIZE]; + struct bpf_insn insns[] = { + BPF_LD_MAP_VALUE(BPF_REG_1, 0, 16), + BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 42), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + int ret, map; + + memset(&map_attr, 0, sizeof(map_attr)); + map_attr.map_type = BPF_MAP_TYPE_ARRAY; + map_attr.key_size = sizeof(int); + map_attr.value_size = 32; + map_attr.max_entries = 1; + + map = bpf_create_map_xattr(&map_attr); + if (map < 0) { + ret = -errno; + cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg)); + pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n", + __func__, cp, -ret); + return ret; + } + + insns[0].imm = map; + + memset(&prg_attr, 0, sizeof(prg_attr)); + prg_attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER; + prg_attr.insns = insns; + prg_attr.insns_cnt = ARRAY_SIZE(insns); + prg_attr.license = "GPL"; + + ret = bpf_load_program_xattr(&prg_attr, NULL, 0); + close(map); + return probe_fd(ret); +} + +static int probe_kern_btf(void) +{ + static const char strs[] = "\0int"; + __u32 types[] = { + /* int */ + BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), + }; + + return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), + strs, sizeof(strs))); +} + +static int probe_kern_btf_func(void) +{ + static const char strs[] = "\0int\0x\0a"; + /* void x(int a) {} */ + __u32 types[] = { + /* int */ + BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + /* FUNC_PROTO */ /* [2] */ + BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0), + BTF_PARAM_ENC(7, 1), + /* FUNC x */ /* [3] */ + BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), 2), + }; + + return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), + strs, sizeof(strs))); +} + +static int probe_kern_btf_func_global(void) +{ + static const char strs[] = "\0int\0x\0a"; + /* static void x(int a) {} */ + __u32 types[] = { + /* int */ + BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + /* FUNC_PROTO */ /* [2] */ + BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0), + BTF_PARAM_ENC(7, 1), + /* FUNC x BTF_FUNC_GLOBAL */ /* [3] */ + BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 2), + }; + + return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), + strs, sizeof(strs))); +} + +static int probe_kern_btf_datasec(void) +{ + static const char strs[] = "\0x\0.data"; + /* static int a; */ + __u32 types[] = { + /* int */ + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + /* VAR x */ /* [2] */ + BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1), + BTF_VAR_STATIC, + /* DATASEC val */ /* [3] */ + BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4), + BTF_VAR_SECINFO_ENC(2, 0, 4), + }; + + return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), + strs, sizeof(strs))); +} + +static int probe_kern_array_mmap(void) +{ + struct bpf_create_map_attr attr = { + .map_type = BPF_MAP_TYPE_ARRAY, + .map_flags = BPF_F_MMAPABLE, + .key_size = sizeof(int), + .value_size = sizeof(int), + .max_entries = 1, + }; + + return probe_fd(bpf_create_map_xattr(&attr)); +} + +static int probe_kern_exp_attach_type(void) +{ + struct bpf_load_program_attr attr; + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + + memset(&attr, 0, sizeof(attr)); + /* use any valid combination of program type and (optional) + * non-zero expected attach type (i.e., not a BPF_CGROUP_INET_INGRESS) + * to see if kernel supports expected_attach_type field for + * BPF_PROG_LOAD command + */ + attr.prog_type = BPF_PROG_TYPE_CGROUP_SOCK; + attr.expected_attach_type = BPF_CGROUP_INET_SOCK_CREATE; + attr.insns = insns; + attr.insns_cnt = ARRAY_SIZE(insns); + attr.license = "GPL"; + + return probe_fd(bpf_load_program_xattr(&attr, NULL, 0)); +} + +static int probe_kern_probe_read_kernel(void) +{ + struct bpf_load_program_attr attr; + struct bpf_insn insns[] = { + BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), /* r1 = r10 (fp) */ + BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8), /* r1 += -8 */ + BPF_MOV64_IMM(BPF_REG_2, 8), /* r2 = 8 */ + BPF_MOV64_IMM(BPF_REG_3, 0), /* r3 = 0 */ + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_probe_read_kernel), + BPF_EXIT_INSN(), + }; + + memset(&attr, 0, sizeof(attr)); + attr.prog_type = BPF_PROG_TYPE_KPROBE; + attr.insns = insns; + attr.insns_cnt = ARRAY_SIZE(insns); + attr.license = "GPL"; + + return probe_fd(bpf_load_program_xattr(&attr, NULL, 0)); +} + +static int probe_prog_bind_map(void) +{ + struct bpf_load_program_attr prg_attr; + struct bpf_create_map_attr map_attr; + char *cp, errmsg[STRERR_BUFSIZE]; + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + int ret, map, prog; + + memset(&map_attr, 0, sizeof(map_attr)); + map_attr.map_type = BPF_MAP_TYPE_ARRAY; + map_attr.key_size = sizeof(int); + map_attr.value_size = 32; + map_attr.max_entries = 1; + + map = bpf_create_map_xattr(&map_attr); + if (map < 0) { + ret = -errno; + cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg)); + pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n", + __func__, cp, -ret); + return ret; + } + + memset(&prg_attr, 0, sizeof(prg_attr)); + prg_attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER; + prg_attr.insns = insns; + prg_attr.insns_cnt = ARRAY_SIZE(insns); + prg_attr.license = "GPL"; + + prog = bpf_load_program_xattr(&prg_attr, NULL, 0); + if (prog < 0) { + close(map); + return 0; + } + + ret = bpf_prog_bind_map(prog, map, NULL); + + close(map); + close(prog); + + return ret >= 0; +} + +enum kern_feature_result { + FEAT_UNKNOWN = 0, + FEAT_SUPPORTED = 1, + FEAT_MISSING = 2, +}; + +typedef int (*feature_probe_fn)(void); + +static struct kern_feature_desc { + const char *desc; + feature_probe_fn probe; + enum kern_feature_result res; +} feature_probes[__FEAT_CNT] = { + [FEAT_PROG_NAME] = { + "BPF program name", probe_kern_prog_name, + }, + [FEAT_GLOBAL_DATA] = { + "global variables", probe_kern_global_data, + }, + [FEAT_BTF] = { + "minimal BTF", probe_kern_btf, + }, + [FEAT_BTF_FUNC] = { + "BTF functions", probe_kern_btf_func, + }, + [FEAT_BTF_GLOBAL_FUNC] = { + "BTF global function", probe_kern_btf_func_global, + }, + [FEAT_BTF_DATASEC] = { + "BTF data section and variable", probe_kern_btf_datasec, + }, + [FEAT_ARRAY_MMAP] = { + "ARRAY map mmap()", probe_kern_array_mmap, + }, + [FEAT_EXP_ATTACH_TYPE] = { + "BPF_PROG_LOAD expected_attach_type attribute", + probe_kern_exp_attach_type, + }, + [FEAT_PROBE_READ_KERN] = { + "bpf_probe_read_kernel() helper", probe_kern_probe_read_kernel, + }, + [FEAT_PROG_BIND_MAP] = { + "BPF_PROG_BIND_MAP support", probe_prog_bind_map, + } +}; + +static bool kernel_supports(enum kern_feature_id feat_id) +{ + struct kern_feature_desc *feat = &feature_probes[feat_id]; + int ret; + + if (READ_ONCE(feat->res) == FEAT_UNKNOWN) { + ret = feat->probe(); + if (ret > 0) { + WRITE_ONCE(feat->res, FEAT_SUPPORTED); + } else if (ret == 0) { + WRITE_ONCE(feat->res, FEAT_MISSING); + } else { + pr_warn("Detection of kernel %s support failed: %d\n", feat->desc, ret); + WRITE_ONCE(feat->res, FEAT_MISSING); + } + } + + return READ_ONCE(feat->res) == FEAT_SUPPORTED; +} + +static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd) +{ + struct bpf_map_info map_info = {}; + char msg[STRERR_BUFSIZE]; + __u32 map_info_len; + int err; + + map_info_len = sizeof(map_info); + + err = bpf_obj_get_info_by_fd(map_fd, &map_info, &map_info_len); + if (err && errno == EINVAL) + err = bpf_get_map_info_from_fdinfo(map_fd, &map_info); + if (err) { + pr_warn("failed to get map info for map FD %d: %s\n", map_fd, + libbpf_strerror_r(errno, msg, sizeof(msg))); + return false; + } + + return (map_info.type == map->def.type && + map_info.key_size == map->def.key_size && + map_info.value_size == map->def.value_size && + map_info.max_entries == map->def.max_entries && + map_info.map_flags == map->def.map_flags); +} + +static int +bpf_object__reuse_map(struct bpf_map *map) +{ + char *cp, errmsg[STRERR_BUFSIZE]; + int err, pin_fd; + + pin_fd = bpf_obj_get(map->pin_path); + if (pin_fd < 0) { + err = -errno; + if (err == -ENOENT) { + pr_debug("found no pinned map to reuse at '%s'\n", + map->pin_path); + return 0; + } + + cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg)); + pr_warn("couldn't retrieve pinned map '%s': %s\n", + map->pin_path, cp); + return err; + } + + if (!map_is_reuse_compat(map, pin_fd)) { + pr_warn("couldn't reuse pinned map at '%s': parameter mismatch\n", + map->pin_path); + close(pin_fd); + return -EINVAL; + } + + err = bpf_map__reuse_fd(map, pin_fd); + if (err) { + close(pin_fd); + return err; + } + map->pinned = true; + pr_debug("reused pinned map at '%s'\n", map->pin_path); + + return 0; +} + +static int +bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map) +{ + enum libbpf_map_type map_type = map->libbpf_type; + char *cp, errmsg[STRERR_BUFSIZE]; + int err, zero = 0; + + err = bpf_map_update_elem(map->fd, &zero, map->mmaped, 0); + if (err) { + err = -errno; + cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); + pr_warn("Error setting initial map(%s) contents: %s\n", + map->name, cp); + return err; + } + + /* Freeze .rodata and .kconfig map as read-only from syscall side. */ + if (map_type == LIBBPF_MAP_RODATA || map_type == LIBBPF_MAP_KCONFIG) { + err = bpf_map_freeze(map->fd); + if (err) { + err = -errno; + cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); + pr_warn("Error freezing map(%s) as read-only: %s\n", + map->name, cp); + return err; + } + } + return 0; +} + +static void bpf_map__destroy(struct bpf_map *map); + +static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map) +{ + struct bpf_create_map_attr create_attr; + struct bpf_map_def *def = &map->def; + int err = 0; + + memset(&create_attr, 0, sizeof(create_attr)); + + if (kernel_supports(FEAT_PROG_NAME)) + create_attr.name = map->name; + create_attr.map_ifindex = map->map_ifindex; + create_attr.map_type = def->type; + create_attr.map_flags = def->map_flags; + create_attr.key_size = def->key_size; + create_attr.value_size = def->value_size; + create_attr.numa_node = map->numa_node; + + if (def->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && !def->max_entries) { + int nr_cpus; + + nr_cpus = libbpf_num_possible_cpus(); + if (nr_cpus < 0) { + pr_warn("map '%s': failed to determine number of system CPUs: %d\n", + map->name, nr_cpus); + return nr_cpus; + } + pr_debug("map '%s': setting size to %d\n", map->name, nr_cpus); + create_attr.max_entries = nr_cpus; + } else { + create_attr.max_entries = def->max_entries; + } + + if (bpf_map__is_struct_ops(map)) + create_attr.btf_vmlinux_value_type_id = + map->btf_vmlinux_value_type_id; + + create_attr.btf_fd = 0; + create_attr.btf_key_type_id = 0; + create_attr.btf_value_type_id = 0; + if (obj->btf && btf__fd(obj->btf) >= 0 && !bpf_map_find_btf_info(obj, map)) { + create_attr.btf_fd = btf__fd(obj->btf); + create_attr.btf_key_type_id = map->btf_key_type_id; + create_attr.btf_value_type_id = map->btf_value_type_id; + } + + if (bpf_map_type__is_map_in_map(def->type)) { + if (map->inner_map) { + err = bpf_object__create_map(obj, map->inner_map); + if (err) { + pr_warn("map '%s': failed to create inner map: %d\n", + map->name, err); + return err; + } + map->inner_map_fd = bpf_map__fd(map->inner_map); + } + if (map->inner_map_fd >= 0) + create_attr.inner_map_fd = map->inner_map_fd; + } + + map->fd = bpf_create_map_xattr(&create_attr); + if (map->fd < 0 && (create_attr.btf_key_type_id || + create_attr.btf_value_type_id)) { + char *cp, errmsg[STRERR_BUFSIZE]; + + err = -errno; + cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); + pr_warn("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n", + map->name, cp, err); + create_attr.btf_fd = 0; + create_attr.btf_key_type_id = 0; + create_attr.btf_value_type_id = 0; + map->btf_key_type_id = 0; + map->btf_value_type_id = 0; + map->fd = bpf_create_map_xattr(&create_attr); + } + + err = map->fd < 0 ? -errno : 0; + + if (bpf_map_type__is_map_in_map(def->type) && map->inner_map) { + bpf_map__destroy(map->inner_map); + zfree(&map->inner_map); + } + + return err; +} + +static int init_map_slots(struct bpf_map *map) +{ + const struct bpf_map *targ_map; + unsigned int i; + int fd, err; + + for (i = 0; i < map->init_slots_sz; i++) { + if (!map->init_slots[i]) + continue; + + targ_map = map->init_slots[i]; + fd = bpf_map__fd(targ_map); + err = bpf_map_update_elem(map->fd, &i, &fd, 0); + if (err) { + err = -errno; + pr_warn("map '%s': failed to initialize slot [%d] to map '%s' fd=%d: %d\n", + map->name, i, targ_map->name, + fd, err); + return err; + } + pr_debug("map '%s': slot [%d] set to map '%s' fd=%d\n", + map->name, i, targ_map->name, fd); + } + + zfree(&map->init_slots); + map->init_slots_sz = 0; + + return 0; +} + +static int +bpf_object__create_maps(struct bpf_object *obj) +{ + struct bpf_map *map; + char *cp, errmsg[STRERR_BUFSIZE]; + unsigned int i, j; + int err; + bool retried; + + for (i = 0; i < obj->nr_maps; i++) { + map = &obj->maps[i]; + + retried = false; +retry: + if (map->pin_path) { + err = bpf_object__reuse_map(map); + if (err) { + pr_warn("map '%s': error reusing pinned map\n", + map->name); + goto err_out; + } + if (retried && map->fd < 0) { + pr_warn("map '%s': cannot find pinned map\n", + map->name); + err = -ENOENT; + goto err_out; + } + } + + if (map->fd >= 0) { + pr_debug("map '%s': skipping creation (preset fd=%d)\n", + map->name, map->fd); + } else { + err = bpf_object__create_map(obj, map); + if (err) + goto err_out; + + pr_debug("map '%s': created successfully, fd=%d\n", + map->name, map->fd); + + if (bpf_map__is_internal(map)) { + err = bpf_object__populate_internal_map(obj, map); + if (err < 0) { + zclose(map->fd); + goto err_out; + } + } + + if (map->init_slots_sz) { + err = init_map_slots(map); + if (err < 0) { + zclose(map->fd); + goto err_out; + } + } + } + + if (map->pin_path && !map->pinned) { + err = bpf_map__pin(map, NULL); + if (err) { + zclose(map->fd); + if (!retried && err == -EEXIST) { + retried = true; + goto retry; + } + pr_warn("map '%s': failed to auto-pin at '%s': %d\n", + map->name, map->pin_path, err); + goto err_out; + } + } + } + + return 0; + +err_out: + cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); + pr_warn("map '%s': failed to create: %s(%d)\n", map->name, cp, err); + pr_perm_msg(err); + for (j = 0; j < i; j++) + zclose(obj->maps[j].fd); + return err; +} + +#define BPF_CORE_SPEC_MAX_LEN 64 + +/* represents BPF CO-RE field or array element accessor */ +struct bpf_core_accessor { + __u32 type_id; /* struct/union type or array element type */ + __u32 idx; /* field index or array index */ + const char *name; /* field name or NULL for array accessor */ +}; + +struct bpf_core_spec { + const struct btf *btf; + /* high-level spec: named fields and array indices only */ + struct bpf_core_accessor spec[BPF_CORE_SPEC_MAX_LEN]; + /* original unresolved (no skip_mods_or_typedefs) root type ID */ + __u32 root_type_id; + /* CO-RE relocation kind */ + enum bpf_core_relo_kind relo_kind; + /* high-level spec length */ + int len; + /* raw, low-level spec: 1-to-1 with accessor spec string */ + int raw_spec[BPF_CORE_SPEC_MAX_LEN]; + /* raw spec length */ + int raw_len; + /* field bit offset represented by spec */ + __u32 bit_offset; +}; + +static bool str_is_empty(const char *s) +{ + return !s || !s[0]; +} + +static bool is_flex_arr(const struct btf *btf, + const struct bpf_core_accessor *acc, + const struct btf_array *arr) +{ + const struct btf_type *t; + + /* not a flexible array, if not inside a struct or has non-zero size */ + if (!acc->name || arr->nelems > 0) + return false; + + /* has to be the last member of enclosing struct */ + t = btf__type_by_id(btf, acc->type_id); + return acc->idx == btf_vlen(t) - 1; +} + +static const char *core_relo_kind_str(enum bpf_core_relo_kind kind) +{ + switch (kind) { + case BPF_FIELD_BYTE_OFFSET: return "byte_off"; + case BPF_FIELD_BYTE_SIZE: return "byte_sz"; + case BPF_FIELD_EXISTS: return "field_exists"; + case BPF_FIELD_SIGNED: return "signed"; + case BPF_FIELD_LSHIFT_U64: return "lshift_u64"; + case BPF_FIELD_RSHIFT_U64: return "rshift_u64"; + case BPF_TYPE_ID_LOCAL: return "local_type_id"; + case BPF_TYPE_ID_TARGET: return "target_type_id"; + case BPF_TYPE_EXISTS: return "type_exists"; + case BPF_TYPE_SIZE: return "type_size"; + case BPF_ENUMVAL_EXISTS: return "enumval_exists"; + case BPF_ENUMVAL_VALUE: return "enumval_value"; + default: return "unknown"; + } +} + +static bool core_relo_is_field_based(enum bpf_core_relo_kind kind) +{ + switch (kind) { + case BPF_FIELD_BYTE_OFFSET: + case BPF_FIELD_BYTE_SIZE: + case BPF_FIELD_EXISTS: + case BPF_FIELD_SIGNED: + case BPF_FIELD_LSHIFT_U64: + case BPF_FIELD_RSHIFT_U64: + return true; + default: + return false; + } +} + +static bool core_relo_is_type_based(enum bpf_core_relo_kind kind) +{ + switch (kind) { + case BPF_TYPE_ID_LOCAL: + case BPF_TYPE_ID_TARGET: + case BPF_TYPE_EXISTS: + case BPF_TYPE_SIZE: + return true; + default: + return false; + } +} + +static bool core_relo_is_enumval_based(enum bpf_core_relo_kind kind) +{ + switch (kind) { + case BPF_ENUMVAL_EXISTS: + case BPF_ENUMVAL_VALUE: + return true; + default: + return false; + } +} + +/* + * Turn bpf_core_relo into a low- and high-level spec representation, + * validating correctness along the way, as well as calculating resulting + * field bit offset, specified by accessor string. Low-level spec captures + * every single level of nestedness, including traversing anonymous + * struct/union members. High-level one only captures semantically meaningful + * "turning points": named fields and array indicies. + * E.g., for this case: + * + * struct sample { + * int __unimportant; + * struct { + * int __1; + * int __2; + * int a[7]; + * }; + * }; + * + * struct sample *s = ...; + * + * int x = &s->a[3]; // access string = '0:1:2:3' + * + * Low-level spec has 1:1 mapping with each element of access string (it's + * just a parsed access string representation): [0, 1, 2, 3]. + * + * High-level spec will capture only 3 points: + * - intial zero-index access by pointer (&s->... is the same as &s[0]...); + * - field 'a' access (corresponds to '2' in low-level spec); + * - array element #3 access (corresponds to '3' in low-level spec). + * + * Type-based relocations (TYPE_EXISTS/TYPE_SIZE, + * TYPE_ID_LOCAL/TYPE_ID_TARGET) don't capture any field information. Their + * spec and raw_spec are kept empty. + * + * Enum value-based relocations (ENUMVAL_EXISTS/ENUMVAL_VALUE) use access + * string to specify enumerator's value index that need to be relocated. + */ +static int bpf_core_parse_spec(const struct btf *btf, + __u32 type_id, + const char *spec_str, + enum bpf_core_relo_kind relo_kind, + struct bpf_core_spec *spec) +{ + int access_idx, parsed_len, i; + struct bpf_core_accessor *acc; + const struct btf_type *t; + const char *name; + __u32 id; + __s64 sz; + + if (str_is_empty(spec_str) || *spec_str == ':') + return -EINVAL; + + memset(spec, 0, sizeof(*spec)); + spec->btf = btf; + spec->root_type_id = type_id; + spec->relo_kind = relo_kind; + + /* type-based relocations don't have a field access string */ + if (core_relo_is_type_based(relo_kind)) { + if (strcmp(spec_str, "0")) + return -EINVAL; + return 0; + } + + /* parse spec_str="0:1:2:3:4" into array raw_spec=[0, 1, 2, 3, 4] */ + while (*spec_str) { + if (*spec_str == ':') + ++spec_str; + if (sscanf(spec_str, "%d%n", &access_idx, &parsed_len) != 1) + return -EINVAL; + if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN) + return -E2BIG; + spec_str += parsed_len; + spec->raw_spec[spec->raw_len++] = access_idx; + } + + if (spec->raw_len == 0) + return -EINVAL; + + t = skip_mods_and_typedefs(btf, type_id, &id); + if (!t) + return -EINVAL; + + access_idx = spec->raw_spec[0]; + acc = &spec->spec[0]; + acc->type_id = id; + acc->idx = access_idx; + spec->len++; + + if (core_relo_is_enumval_based(relo_kind)) { + if (!btf_is_enum(t) || spec->raw_len > 1 || access_idx >= btf_vlen(t)) + return -EINVAL; + + /* record enumerator name in a first accessor */ + acc->name = btf__name_by_offset(btf, btf_enum(t)[access_idx].name_off); + return 0; + } + + if (!core_relo_is_field_based(relo_kind)) + return -EINVAL; + + sz = btf__resolve_size(btf, id); + if (sz < 0) + return sz; + spec->bit_offset = access_idx * sz * 8; + + for (i = 1; i < spec->raw_len; i++) { + t = skip_mods_and_typedefs(btf, id, &id); + if (!t) + return -EINVAL; + + access_idx = spec->raw_spec[i]; + acc = &spec->spec[spec->len]; + + if (btf_is_composite(t)) { + const struct btf_member *m; + __u32 bit_offset; + + if (access_idx >= btf_vlen(t)) + return -EINVAL; + + bit_offset = btf_member_bit_offset(t, access_idx); + spec->bit_offset += bit_offset; + + m = btf_members(t) + access_idx; + if (m->name_off) { + name = btf__name_by_offset(btf, m->name_off); + if (str_is_empty(name)) + return -EINVAL; + + acc->type_id = id; + acc->idx = access_idx; + acc->name = name; + spec->len++; + } + + id = m->type; + } else if (btf_is_array(t)) { + const struct btf_array *a = btf_array(t); + bool flex; + + t = skip_mods_and_typedefs(btf, a->type, &id); + if (!t) + return -EINVAL; + + flex = is_flex_arr(btf, acc - 1, a); + if (!flex && access_idx >= a->nelems) + return -EINVAL; + + spec->spec[spec->len].type_id = id; + spec->spec[spec->len].idx = access_idx; + spec->len++; + + sz = btf__resolve_size(btf, id); + if (sz < 0) + return sz; + spec->bit_offset += access_idx * sz * 8; + } else { + pr_warn("relo for [%u] %s (at idx %d) captures type [%d] of unexpected kind %s\n", + type_id, spec_str, i, id, btf_kind_str(t)); + return -EINVAL; + } + } + + return 0; +} + +static bool bpf_core_is_flavor_sep(const char *s) +{ + /* check X___Y name pattern, where X and Y are not underscores */ + return s[0] != '_' && /* X */ + s[1] == '_' && s[2] == '_' && s[3] == '_' && /* ___ */ + s[4] != '_'; /* Y */ +} + +/* Given 'some_struct_name___with_flavor' return the length of a name prefix + * before last triple underscore. Struct name part after last triple + * underscore is ignored by BPF CO-RE relocation during relocation matching. + */ +static size_t bpf_core_essential_name_len(const char *name) +{ + size_t n = strlen(name); + int i; + + for (i = n - 5; i >= 0; i--) { + if (bpf_core_is_flavor_sep(name + i)) + return i + 1; + } + return n; +} + +/* dynamically sized list of type IDs */ +struct ids_vec { + __u32 *data; + int len; +}; + +static void bpf_core_free_cands(struct ids_vec *cand_ids) +{ + free(cand_ids->data); + free(cand_ids); +} + +static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf, + __u32 local_type_id, + const struct btf *targ_btf) +{ + size_t local_essent_len, targ_essent_len; + const char *local_name, *targ_name; + const struct btf_type *t, *local_t; + struct ids_vec *cand_ids; + __u32 *new_ids; + int i, err, n; + + local_t = btf__type_by_id(local_btf, local_type_id); + if (!local_t) + return ERR_PTR(-EINVAL); + + local_name = btf__name_by_offset(local_btf, local_t->name_off); + if (str_is_empty(local_name)) + return ERR_PTR(-EINVAL); + local_essent_len = bpf_core_essential_name_len(local_name); + + cand_ids = calloc(1, sizeof(*cand_ids)); + if (!cand_ids) + return ERR_PTR(-ENOMEM); + + n = btf__get_nr_types(targ_btf); + for (i = 1; i <= n; i++) { + t = btf__type_by_id(targ_btf, i); + if (btf_kind(t) != btf_kind(local_t)) + continue; + + targ_name = btf__name_by_offset(targ_btf, t->name_off); + if (str_is_empty(targ_name)) + continue; + + targ_essent_len = bpf_core_essential_name_len(targ_name); + if (targ_essent_len != local_essent_len) + continue; + + if (strncmp(local_name, targ_name, local_essent_len) == 0) { + pr_debug("CO-RE relocating [%d] %s %s: found target candidate [%d] %s %s\n", + local_type_id, btf_kind_str(local_t), + local_name, i, btf_kind_str(t), targ_name); + new_ids = libbpf_reallocarray(cand_ids->data, + cand_ids->len + 1, + sizeof(*cand_ids->data)); + if (!new_ids) { + err = -ENOMEM; + goto err_out; + } + cand_ids->data = new_ids; + cand_ids->data[cand_ids->len++] = i; + } + } + return cand_ids; +err_out: + bpf_core_free_cands(cand_ids); + return ERR_PTR(err); +} + +/* Check two types for compatibility for the purpose of field access + * relocation. const/volatile/restrict and typedefs are skipped to ensure we + * are relocating semantically compatible entities: + * - any two STRUCTs/UNIONs are compatible and can be mixed; + * - any two FWDs are compatible, if their names match (modulo flavor suffix); + * - any two PTRs are always compatible; + * - for ENUMs, names should be the same (ignoring flavor suffix) or at + * least one of enums should be anonymous; + * - for ENUMs, check sizes, names are ignored; + * - for INT, size and signedness are ignored; + * - for ARRAY, dimensionality is ignored, element types are checked for + * compatibility recursively; + * - everything else shouldn't be ever a target of relocation. + * These rules are not set in stone and probably will be adjusted as we get + * more experience with using BPF CO-RE relocations. + */ +static int bpf_core_fields_are_compat(const struct btf *local_btf, + __u32 local_id, + const struct btf *targ_btf, + __u32 targ_id) +{ + const struct btf_type *local_type, *targ_type; + +recur: + local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id); + targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id); + if (!local_type || !targ_type) + return -EINVAL; + + if (btf_is_composite(local_type) && btf_is_composite(targ_type)) + return 1; + if (btf_kind(local_type) != btf_kind(targ_type)) + return 0; + + switch (btf_kind(local_type)) { + case BTF_KIND_PTR: + return 1; + case BTF_KIND_FWD: + case BTF_KIND_ENUM: { + const char *local_name, *targ_name; + size_t local_len, targ_len; + + local_name = btf__name_by_offset(local_btf, + local_type->name_off); + targ_name = btf__name_by_offset(targ_btf, targ_type->name_off); + local_len = bpf_core_essential_name_len(local_name); + targ_len = bpf_core_essential_name_len(targ_name); + /* one of them is anonymous or both w/ same flavor-less names */ + return local_len == 0 || targ_len == 0 || + (local_len == targ_len && + strncmp(local_name, targ_name, local_len) == 0); + } + case BTF_KIND_INT: + /* just reject deprecated bitfield-like integers; all other + * integers are by default compatible between each other + */ + return btf_int_offset(local_type) == 0 && + btf_int_offset(targ_type) == 0; + case BTF_KIND_ARRAY: + local_id = btf_array(local_type)->type; + targ_id = btf_array(targ_type)->type; + goto recur; + default: + pr_warn("unexpected kind %d relocated, local [%d], target [%d]\n", + btf_kind(local_type), local_id, targ_id); + return 0; + } +} + +/* + * Given single high-level named field accessor in local type, find + * corresponding high-level accessor for a target type. Along the way, + * maintain low-level spec for target as well. Also keep updating target + * bit offset. + * + * Searching is performed through recursive exhaustive enumeration of all + * fields of a struct/union. If there are any anonymous (embedded) + * structs/unions, they are recursively searched as well. If field with + * desired name is found, check compatibility between local and target types, + * before returning result. + * + * 1 is returned, if field is found. + * 0 is returned if no compatible field is found. + * <0 is returned on error. + */ +static int bpf_core_match_member(const struct btf *local_btf, + const struct bpf_core_accessor *local_acc, + const struct btf *targ_btf, + __u32 targ_id, + struct bpf_core_spec *spec, + __u32 *next_targ_id) +{ + const struct btf_type *local_type, *targ_type; + const struct btf_member *local_member, *m; + const char *local_name, *targ_name; + __u32 local_id; + int i, n, found; + + targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id); + if (!targ_type) + return -EINVAL; + if (!btf_is_composite(targ_type)) + return 0; + + local_id = local_acc->type_id; + local_type = btf__type_by_id(local_btf, local_id); + local_member = btf_members(local_type) + local_acc->idx; + local_name = btf__name_by_offset(local_btf, local_member->name_off); + + n = btf_vlen(targ_type); + m = btf_members(targ_type); + for (i = 0; i < n; i++, m++) { + __u32 bit_offset; + + bit_offset = btf_member_bit_offset(targ_type, i); + + /* too deep struct/union/array nesting */ + if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN) + return -E2BIG; + + /* speculate this member will be the good one */ + spec->bit_offset += bit_offset; + spec->raw_spec[spec->raw_len++] = i; + + targ_name = btf__name_by_offset(targ_btf, m->name_off); + if (str_is_empty(targ_name)) { + /* embedded struct/union, we need to go deeper */ + found = bpf_core_match_member(local_btf, local_acc, + targ_btf, m->type, + spec, next_targ_id); + if (found) /* either found or error */ + return found; + } else if (strcmp(local_name, targ_name) == 0) { + /* matching named field */ + struct bpf_core_accessor *targ_acc; + + targ_acc = &spec->spec[spec->len++]; + targ_acc->type_id = targ_id; + targ_acc->idx = i; + targ_acc->name = targ_name; + + *next_targ_id = m->type; + found = bpf_core_fields_are_compat(local_btf, + local_member->type, + targ_btf, m->type); + if (!found) + spec->len--; /* pop accessor */ + return found; + } + /* member turned out not to be what we looked for */ + spec->bit_offset -= bit_offset; + spec->raw_len--; + } + + return 0; +} + +/* Check local and target types for compatibility. This check is used for + * type-based CO-RE relocations and follow slightly different rules than + * field-based relocations. This function assumes that root types were already + * checked for name match. Beyond that initial root-level name check, names + * are completely ignored. Compatibility rules are as follows: + * - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs are considered compatible, but + * kind should match for local and target types (i.e., STRUCT is not + * compatible with UNION); + * - for ENUMs, the size is ignored; + * - for INT, size and signedness are ignored; + * - for ARRAY, dimensionality is ignored, element types are checked for + * compatibility recursively; + * - CONST/VOLATILE/RESTRICT modifiers are ignored; + * - TYPEDEFs/PTRs are compatible if types they pointing to are compatible; + * - FUNC_PROTOs are compatible if they have compatible signature: same + * number of input args and compatible return and argument types. + * These rules are not set in stone and probably will be adjusted as we get + * more experience with using BPF CO-RE relocations. + */ +static int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id, + const struct btf *targ_btf, __u32 targ_id) +{ + const struct btf_type *local_type, *targ_type; + int depth = 32; /* max recursion depth */ + + /* caller made sure that names match (ignoring flavor suffix) */ + local_type = btf__type_by_id(local_btf, local_id); + targ_type = btf__type_by_id(targ_btf, targ_id); + if (btf_kind(local_type) != btf_kind(targ_type)) + return 0; + +recur: + depth--; + if (depth < 0) + return -EINVAL; + + local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id); + targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id); + if (!local_type || !targ_type) + return -EINVAL; + + if (btf_kind(local_type) != btf_kind(targ_type)) + return 0; + + switch (btf_kind(local_type)) { + case BTF_KIND_UNKN: + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + case BTF_KIND_ENUM: + case BTF_KIND_FWD: + return 1; + case BTF_KIND_INT: + /* just reject deprecated bitfield-like integers; all other + * integers are by default compatible between each other + */ + return btf_int_offset(local_type) == 0 && btf_int_offset(targ_type) == 0; + case BTF_KIND_PTR: + local_id = local_type->type; + targ_id = targ_type->type; + goto recur; + case BTF_KIND_ARRAY: + local_id = btf_array(local_type)->type; + targ_id = btf_array(targ_type)->type; + goto recur; + case BTF_KIND_FUNC_PROTO: { + struct btf_param *local_p = btf_params(local_type); + struct btf_param *targ_p = btf_params(targ_type); + __u16 local_vlen = btf_vlen(local_type); + __u16 targ_vlen = btf_vlen(targ_type); + int i, err; + + if (local_vlen != targ_vlen) + return 0; + + for (i = 0; i < local_vlen; i++, local_p++, targ_p++) { + skip_mods_and_typedefs(local_btf, local_p->type, &local_id); + skip_mods_and_typedefs(targ_btf, targ_p->type, &targ_id); + err = bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id); + if (err <= 0) + return err; + } + + /* tail recurse for return type check */ + skip_mods_and_typedefs(local_btf, local_type->type, &local_id); + skip_mods_and_typedefs(targ_btf, targ_type->type, &targ_id); + goto recur; + } + default: + pr_warn("unexpected kind %s relocated, local [%d], target [%d]\n", + btf_kind_str(local_type), local_id, targ_id); + return 0; + } +} + +/* + * Try to match local spec to a target type and, if successful, produce full + * target spec (high-level, low-level + bit offset). + */ +static int bpf_core_spec_match(struct bpf_core_spec *local_spec, + const struct btf *targ_btf, __u32 targ_id, + struct bpf_core_spec *targ_spec) +{ + const struct btf_type *targ_type; + const struct bpf_core_accessor *local_acc; + struct bpf_core_accessor *targ_acc; + int i, sz, matched; + + memset(targ_spec, 0, sizeof(*targ_spec)); + targ_spec->btf = targ_btf; + targ_spec->root_type_id = targ_id; + targ_spec->relo_kind = local_spec->relo_kind; + + if (core_relo_is_type_based(local_spec->relo_kind)) { + return bpf_core_types_are_compat(local_spec->btf, + local_spec->root_type_id, + targ_btf, targ_id); + } + + local_acc = &local_spec->spec[0]; + targ_acc = &targ_spec->spec[0]; + + if (core_relo_is_enumval_based(local_spec->relo_kind)) { + size_t local_essent_len, targ_essent_len; + const struct btf_enum *e; + const char *targ_name; + + /* has to resolve to an enum */ + targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id, &targ_id); + if (!btf_is_enum(targ_type)) + return 0; + + local_essent_len = bpf_core_essential_name_len(local_acc->name); + + for (i = 0, e = btf_enum(targ_type); i < btf_vlen(targ_type); i++, e++) { + targ_name = btf__name_by_offset(targ_spec->btf, e->name_off); + targ_essent_len = bpf_core_essential_name_len(targ_name); + if (targ_essent_len != local_essent_len) + continue; + if (strncmp(local_acc->name, targ_name, local_essent_len) == 0) { + targ_acc->type_id = targ_id; + targ_acc->idx = i; + targ_acc->name = targ_name; + targ_spec->len++; + targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx; + targ_spec->raw_len++; + return 1; + } + } + return 0; + } + + if (!core_relo_is_field_based(local_spec->relo_kind)) + return -EINVAL; + + for (i = 0; i < local_spec->len; i++, local_acc++, targ_acc++) { + targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id, + &targ_id); + if (!targ_type) + return -EINVAL; + + if (local_acc->name) { + matched = bpf_core_match_member(local_spec->btf, + local_acc, + targ_btf, targ_id, + targ_spec, &targ_id); + if (matched <= 0) + return matched; + } else { + /* for i=0, targ_id is already treated as array element + * type (because it's the original struct), for others + * we should find array element type first + */ + if (i > 0) { + const struct btf_array *a; + bool flex; + + if (!btf_is_array(targ_type)) + return 0; + + a = btf_array(targ_type); + flex = is_flex_arr(targ_btf, targ_acc - 1, a); + if (!flex && local_acc->idx >= a->nelems) + return 0; + if (!skip_mods_and_typedefs(targ_btf, a->type, + &targ_id)) + return -EINVAL; + } + + /* too deep struct/union/array nesting */ + if (targ_spec->raw_len == BPF_CORE_SPEC_MAX_LEN) + return -E2BIG; + + targ_acc->type_id = targ_id; + targ_acc->idx = local_acc->idx; + targ_acc->name = NULL; + targ_spec->len++; + targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx; + targ_spec->raw_len++; + + sz = btf__resolve_size(targ_btf, targ_id); + if (sz < 0) + return sz; + targ_spec->bit_offset += local_acc->idx * sz * 8; + } + } + + return 1; +} + +static int bpf_core_calc_field_relo(const struct bpf_program *prog, + const struct bpf_core_relo *relo, + const struct bpf_core_spec *spec, + __u32 *val, __u32 *field_sz, __u32 *type_id, + bool *validate) +{ + const struct bpf_core_accessor *acc; + const struct btf_type *t; + __u32 byte_off, byte_sz, bit_off, bit_sz, field_type_id; + const struct btf_member *m; + const struct btf_type *mt; + bool bitfield; + __s64 sz; + + *field_sz = 0; + + if (relo->kind == BPF_FIELD_EXISTS) { + *val = spec ? 1 : 0; + return 0; + } + + if (!spec) + return -EUCLEAN; /* request instruction poisoning */ + + acc = &spec->spec[spec->len - 1]; + t = btf__type_by_id(spec->btf, acc->type_id); + + /* a[n] accessor needs special handling */ + if (!acc->name) { + if (relo->kind == BPF_FIELD_BYTE_OFFSET) { + *val = spec->bit_offset / 8; + /* remember field size for load/store mem size */ + sz = btf__resolve_size(spec->btf, acc->type_id); + if (sz < 0) + return -EINVAL; + *field_sz = sz; + *type_id = acc->type_id; + } else if (relo->kind == BPF_FIELD_BYTE_SIZE) { + sz = btf__resolve_size(spec->btf, acc->type_id); + if (sz < 0) + return -EINVAL; + *val = sz; + } else { + pr_warn("prog '%s': relo %d at insn #%d can't be applied to array access\n", + prog->name, relo->kind, relo->insn_off / 8); + return -EINVAL; + } + if (validate) + *validate = true; + return 0; + } + + m = btf_members(t) + acc->idx; + mt = skip_mods_and_typedefs(spec->btf, m->type, &field_type_id); + bit_off = spec->bit_offset; + bit_sz = btf_member_bitfield_size(t, acc->idx); + + bitfield = bit_sz > 0; + if (bitfield) { + byte_sz = mt->size; + byte_off = bit_off / 8 / byte_sz * byte_sz; + /* figure out smallest int size necessary for bitfield load */ + while (bit_off + bit_sz - byte_off * 8 > byte_sz * 8) { + if (byte_sz >= 8) { + /* bitfield can't be read with 64-bit read */ + pr_warn("prog '%s': relo %d at insn #%d can't be satisfied for bitfield\n", + prog->name, relo->kind, relo->insn_off / 8); + return -E2BIG; + } + byte_sz *= 2; + byte_off = bit_off / 8 / byte_sz * byte_sz; + } + } else { + sz = btf__resolve_size(spec->btf, field_type_id); + if (sz < 0) + return -EINVAL; + byte_sz = sz; + byte_off = spec->bit_offset / 8; + bit_sz = byte_sz * 8; + } + + /* for bitfields, all the relocatable aspects are ambiguous and we + * might disagree with compiler, so turn off validation of expected + * value, except for signedness + */ + if (validate) + *validate = !bitfield; + + switch (relo->kind) { + case BPF_FIELD_BYTE_OFFSET: + *val = byte_off; + if (!bitfield) { + *field_sz = byte_sz; + *type_id = field_type_id; + } + break; + case BPF_FIELD_BYTE_SIZE: + *val = byte_sz; + break; + case BPF_FIELD_SIGNED: + /* enums will be assumed unsigned */ + *val = btf_is_enum(mt) || + (btf_int_encoding(mt) & BTF_INT_SIGNED); + if (validate) + *validate = true; /* signedness is never ambiguous */ + break; + case BPF_FIELD_LSHIFT_U64: +#if __BYTE_ORDER == __LITTLE_ENDIAN + *val = 64 - (bit_off + bit_sz - byte_off * 8); +#else + *val = (8 - byte_sz) * 8 + (bit_off - byte_off * 8); +#endif + break; + case BPF_FIELD_RSHIFT_U64: + *val = 64 - bit_sz; + if (validate) + *validate = true; /* right shift is never ambiguous */ + break; + case BPF_FIELD_EXISTS: + default: + return -EOPNOTSUPP; + } + + return 0; +} + +static int bpf_core_calc_type_relo(const struct bpf_core_relo *relo, + const struct bpf_core_spec *spec, + __u32 *val) +{ + __s64 sz; + + /* type-based relos return zero when target type is not found */ + if (!spec) { + *val = 0; + return 0; + } + + switch (relo->kind) { + case BPF_TYPE_ID_TARGET: + *val = spec->root_type_id; + break; + case BPF_TYPE_EXISTS: + *val = 1; + break; + case BPF_TYPE_SIZE: + sz = btf__resolve_size(spec->btf, spec->root_type_id); + if (sz < 0) + return -EINVAL; + *val = sz; + break; + case BPF_TYPE_ID_LOCAL: + /* BPF_TYPE_ID_LOCAL is handled specially and shouldn't get here */ + default: + return -EOPNOTSUPP; + } + + return 0; +} + +static int bpf_core_calc_enumval_relo(const struct bpf_core_relo *relo, + const struct bpf_core_spec *spec, + __u32 *val) +{ + const struct btf_type *t; + const struct btf_enum *e; + + switch (relo->kind) { + case BPF_ENUMVAL_EXISTS: + *val = spec ? 1 : 0; + break; + case BPF_ENUMVAL_VALUE: + if (!spec) + return -EUCLEAN; /* request instruction poisoning */ + t = btf__type_by_id(spec->btf, spec->spec[0].type_id); + e = btf_enum(t) + spec->spec[0].idx; + *val = e->val; + break; + default: + return -EOPNOTSUPP; + } + + return 0; +} + +struct bpf_core_relo_res +{ + /* expected value in the instruction, unless validate == false */ + __u32 orig_val; + /* new value that needs to be patched up to */ + __u32 new_val; + /* relocation unsuccessful, poison instruction, but don't fail load */ + bool poison; + /* some relocations can't be validated against orig_val */ + bool validate; + /* for field byte offset relocations or the forms: + * *(T *)(rX + <off>) = rY + * rX = *(T *)(rY + <off>), + * we remember original and resolved field size to adjust direct + * memory loads of pointers and integers; this is necessary for 32-bit + * host kernel architectures, but also allows to automatically + * relocate fields that were resized from, e.g., u32 to u64, etc. + */ + bool fail_memsz_adjust; + __u32 orig_sz; + __u32 orig_type_id; + __u32 new_sz; + __u32 new_type_id; +}; + +/* Calculate original and target relocation values, given local and target + * specs and relocation kind. These values are calculated for each candidate. + * If there are multiple candidates, resulting values should all be consistent + * with each other. Otherwise, libbpf will refuse to proceed due to ambiguity. + * If instruction has to be poisoned, *poison will be set to true. + */ +static int bpf_core_calc_relo(const struct bpf_program *prog, + const struct bpf_core_relo *relo, + int relo_idx, + const struct bpf_core_spec *local_spec, + const struct bpf_core_spec *targ_spec, + struct bpf_core_relo_res *res) +{ + int err = -EOPNOTSUPP; + + res->orig_val = 0; + res->new_val = 0; + res->poison = false; + res->validate = true; + res->fail_memsz_adjust = false; + res->orig_sz = res->new_sz = 0; + res->orig_type_id = res->new_type_id = 0; + + if (core_relo_is_field_based(relo->kind)) { + err = bpf_core_calc_field_relo(prog, relo, local_spec, + &res->orig_val, &res->orig_sz, + &res->orig_type_id, &res->validate); + err = err ?: bpf_core_calc_field_relo(prog, relo, targ_spec, + &res->new_val, &res->new_sz, + &res->new_type_id, NULL); + if (err) + goto done; + /* Validate if it's safe to adjust load/store memory size. + * Adjustments are performed only if original and new memory + * sizes differ. + */ + res->fail_memsz_adjust = false; + if (res->orig_sz != res->new_sz) { + const struct btf_type *orig_t, *new_t; + + orig_t = btf__type_by_id(local_spec->btf, res->orig_type_id); + new_t = btf__type_by_id(targ_spec->btf, res->new_type_id); + + /* There are two use cases in which it's safe to + * adjust load/store's mem size: + * - reading a 32-bit kernel pointer, while on BPF + * size pointers are always 64-bit; in this case + * it's safe to "downsize" instruction size due to + * pointer being treated as unsigned integer with + * zero-extended upper 32-bits; + * - reading unsigned integers, again due to + * zero-extension is preserving the value correctly. + * + * In all other cases it's incorrect to attempt to + * load/store field because read value will be + * incorrect, so we poison relocated instruction. + */ + if (btf_is_ptr(orig_t) && btf_is_ptr(new_t)) + goto done; + if (btf_is_int(orig_t) && btf_is_int(new_t) && + btf_int_encoding(orig_t) != BTF_INT_SIGNED && + btf_int_encoding(new_t) != BTF_INT_SIGNED) + goto done; + + /* mark as invalid mem size adjustment, but this will + * only be checked for LDX/STX/ST insns + */ + res->fail_memsz_adjust = true; + } + } else if (core_relo_is_type_based(relo->kind)) { + err = bpf_core_calc_type_relo(relo, local_spec, &res->orig_val); + err = err ?: bpf_core_calc_type_relo(relo, targ_spec, &res->new_val); + } else if (core_relo_is_enumval_based(relo->kind)) { + err = bpf_core_calc_enumval_relo(relo, local_spec, &res->orig_val); + err = err ?: bpf_core_calc_enumval_relo(relo, targ_spec, &res->new_val); + } + +done: + if (err == -EUCLEAN) { + /* EUCLEAN is used to signal instruction poisoning request */ + res->poison = true; + err = 0; + } else if (err == -EOPNOTSUPP) { + /* EOPNOTSUPP means unknown/unsupported relocation */ + pr_warn("prog '%s': relo #%d: unrecognized CO-RE relocation %s (%d) at insn #%d\n", + prog->name, relo_idx, core_relo_kind_str(relo->kind), + relo->kind, relo->insn_off / 8); + } + + return err; +} + +/* + * Turn instruction for which CO_RE relocation failed into invalid one with + * distinct signature. + */ +static void bpf_core_poison_insn(struct bpf_program *prog, int relo_idx, + int insn_idx, struct bpf_insn *insn) +{ + pr_debug("prog '%s': relo #%d: substituting insn #%d w/ invalid insn\n", + prog->name, relo_idx, insn_idx); + insn->code = BPF_JMP | BPF_CALL; + insn->dst_reg = 0; + insn->src_reg = 0; + insn->off = 0; + /* if this instruction is reachable (not a dead code), + * verifier will complain with the following message: + * invalid func unknown#195896080 + */ + insn->imm = 195896080; /* => 0xbad2310 => "bad relo" */ +} + +static bool is_ldimm64(struct bpf_insn *insn) +{ + return insn->code == (BPF_LD | BPF_IMM | BPF_DW); +} + +static int insn_bpf_size_to_bytes(struct bpf_insn *insn) +{ + switch (BPF_SIZE(insn->code)) { + case BPF_DW: return 8; + case BPF_W: return 4; + case BPF_H: return 2; + case BPF_B: return 1; + default: return -1; + } +} + +static int insn_bytes_to_bpf_size(__u32 sz) +{ + switch (sz) { + case 8: return BPF_DW; + case 4: return BPF_W; + case 2: return BPF_H; + case 1: return BPF_B; + default: return -1; + } +} + +/* + * Patch relocatable BPF instruction. + * + * Patched value is determined by relocation kind and target specification. + * For existence relocations target spec will be NULL if field/type is not found. + * Expected insn->imm value is determined using relocation kind and local + * spec, and is checked before patching instruction. If actual insn->imm value + * is wrong, bail out with error. + * + * Currently supported classes of BPF instruction are: + * 1. rX = <imm> (assignment with immediate operand); + * 2. rX += <imm> (arithmetic operations with immediate operand); + * 3. rX = <imm64> (load with 64-bit immediate value); + * 4. rX = *(T *)(rY + <off>), where T is one of {u8, u16, u32, u64}; + * 5. *(T *)(rX + <off>) = rY, where T is one of {u8, u16, u32, u64}; + * 6. *(T *)(rX + <off>) = <imm>, where T is one of {u8, u16, u32, u64}. + */ +static int bpf_core_patch_insn(struct bpf_program *prog, + const struct bpf_core_relo *relo, + int relo_idx, + const struct bpf_core_relo_res *res) +{ + __u32 orig_val, new_val; + struct bpf_insn *insn; + int insn_idx; + __u8 class; + + if (relo->insn_off % BPF_INSN_SZ) + return -EINVAL; + insn_idx = relo->insn_off / BPF_INSN_SZ; + /* adjust insn_idx from section frame of reference to the local + * program's frame of reference; (sub-)program code is not yet + * relocated, so it's enough to just subtract in-section offset + */ + insn_idx = insn_idx - prog->sec_insn_off; + insn = &prog->insns[insn_idx]; + class = BPF_CLASS(insn->code); + + if (res->poison) { +poison: + /* poison second part of ldimm64 to avoid confusing error from + * verifier about "unknown opcode 00" + */ + if (is_ldimm64(insn)) + bpf_core_poison_insn(prog, relo_idx, insn_idx + 1, insn + 1); + bpf_core_poison_insn(prog, relo_idx, insn_idx, insn); + return 0; + } + + orig_val = res->orig_val; + new_val = res->new_val; + + switch (class) { + case BPF_ALU: + case BPF_ALU64: + if (BPF_SRC(insn->code) != BPF_K) + return -EINVAL; + if (res->validate && insn->imm != orig_val) { + pr_warn("prog '%s': relo #%d: unexpected insn #%d (ALU/ALU64) value: got %u, exp %u -> %u\n", + prog->name, relo_idx, + insn_idx, insn->imm, orig_val, new_val); + return -EINVAL; + } + orig_val = insn->imm; + insn->imm = new_val; + pr_debug("prog '%s': relo #%d: patched insn #%d (ALU/ALU64) imm %u -> %u\n", + prog->name, relo_idx, insn_idx, + orig_val, new_val); + break; + case BPF_LDX: + case BPF_ST: + case BPF_STX: + if (res->validate && insn->off != orig_val) { + pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDX/ST/STX) value: got %u, exp %u -> %u\n", + prog->name, relo_idx, insn_idx, insn->off, orig_val, new_val); + return -EINVAL; + } + if (new_val > SHRT_MAX) { + pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) value too big: %u\n", + prog->name, relo_idx, insn_idx, new_val); + return -ERANGE; + } + if (res->fail_memsz_adjust) { + pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) accesses field incorrectly. " + "Make sure you are accessing pointers, unsigned integers, or fields of matching type and size.\n", + prog->name, relo_idx, insn_idx); + goto poison; + } + + orig_val = insn->off; + insn->off = new_val; + pr_debug("prog '%s': relo #%d: patched insn #%d (LDX/ST/STX) off %u -> %u\n", + prog->name, relo_idx, insn_idx, orig_val, new_val); + + if (res->new_sz != res->orig_sz) { + int insn_bytes_sz, insn_bpf_sz; + + insn_bytes_sz = insn_bpf_size_to_bytes(insn); + if (insn_bytes_sz != res->orig_sz) { + pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) unexpected mem size: got %d, exp %u\n", + prog->name, relo_idx, insn_idx, insn_bytes_sz, res->orig_sz); + return -EINVAL; + } + + insn_bpf_sz = insn_bytes_to_bpf_size(res->new_sz); + if (insn_bpf_sz < 0) { + pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) invalid new mem size: %u\n", + prog->name, relo_idx, insn_idx, res->new_sz); + return -EINVAL; + } + + insn->code = BPF_MODE(insn->code) | insn_bpf_sz | BPF_CLASS(insn->code); + pr_debug("prog '%s': relo #%d: patched insn #%d (LDX/ST/STX) mem_sz %u -> %u\n", + prog->name, relo_idx, insn_idx, res->orig_sz, res->new_sz); + } + break; + case BPF_LD: { + __u64 imm; + + if (!is_ldimm64(insn) || + insn[0].src_reg != 0 || insn[0].off != 0 || + insn_idx + 1 >= prog->insns_cnt || + insn[1].code != 0 || insn[1].dst_reg != 0 || + insn[1].src_reg != 0 || insn[1].off != 0) { + pr_warn("prog '%s': relo #%d: insn #%d (LDIMM64) has unexpected form\n", + prog->name, relo_idx, insn_idx); + return -EINVAL; + } + + imm = insn[0].imm + ((__u64)insn[1].imm << 32); + if (res->validate && imm != orig_val) { + pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDIMM64) value: got %llu, exp %u -> %u\n", + prog->name, relo_idx, + insn_idx, (unsigned long long)imm, + orig_val, new_val); + return -EINVAL; + } + + insn[0].imm = new_val; + insn[1].imm = 0; /* currently only 32-bit values are supported */ + pr_debug("prog '%s': relo #%d: patched insn #%d (LDIMM64) imm64 %llu -> %u\n", + prog->name, relo_idx, insn_idx, + (unsigned long long)imm, new_val); + break; + } + default: + pr_warn("prog '%s': relo #%d: trying to relocate unrecognized insn #%d, code:0x%x, src:0x%x, dst:0x%x, off:0x%x, imm:0x%x\n", + prog->name, relo_idx, insn_idx, insn->code, + insn->src_reg, insn->dst_reg, insn->off, insn->imm); + return -EINVAL; + } + + return 0; +} + +/* Output spec definition in the format: + * [<type-id>] (<type-name>) + <raw-spec> => <offset>@<spec>, + * where <spec> is a C-syntax view of recorded field access, e.g.: x.a[3].b + */ +static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec) +{ + const struct btf_type *t; + const struct btf_enum *e; + const char *s; + __u32 type_id; + int i; + + type_id = spec->root_type_id; + t = btf__type_by_id(spec->btf, type_id); + s = btf__name_by_offset(spec->btf, t->name_off); + + libbpf_print(level, "[%u] %s %s", type_id, btf_kind_str(t), str_is_empty(s) ? "<anon>" : s); + + if (core_relo_is_type_based(spec->relo_kind)) + return; + + if (core_relo_is_enumval_based(spec->relo_kind)) { + t = skip_mods_and_typedefs(spec->btf, type_id, NULL); + e = btf_enum(t) + spec->raw_spec[0]; + s = btf__name_by_offset(spec->btf, e->name_off); + + libbpf_print(level, "::%s = %u", s, e->val); + return; + } + + if (core_relo_is_field_based(spec->relo_kind)) { + for (i = 0; i < spec->len; i++) { + if (spec->spec[i].name) + libbpf_print(level, ".%s", spec->spec[i].name); + else if (i > 0 || spec->spec[i].idx > 0) + libbpf_print(level, "[%u]", spec->spec[i].idx); + } + + libbpf_print(level, " ("); + for (i = 0; i < spec->raw_len; i++) + libbpf_print(level, "%s%d", i == 0 ? "" : ":", spec->raw_spec[i]); + + if (spec->bit_offset % 8) + libbpf_print(level, " @ offset %u.%u)", + spec->bit_offset / 8, spec->bit_offset % 8); + else + libbpf_print(level, " @ offset %u)", spec->bit_offset / 8); + return; + } +} + +static size_t bpf_core_hash_fn(const void *key, void *ctx) +{ + return (size_t)key; +} + +static bool bpf_core_equal_fn(const void *k1, const void *k2, void *ctx) +{ + return k1 == k2; +} + +static void *u32_as_hash_key(__u32 x) +{ + return (void *)(uintptr_t)x; +} + +/* + * CO-RE relocate single instruction. + * + * The outline and important points of the algorithm: + * 1. For given local type, find corresponding candidate target types. + * Candidate type is a type with the same "essential" name, ignoring + * everything after last triple underscore (___). E.g., `sample`, + * `sample___flavor_one`, `sample___flavor_another_one`, are all candidates + * for each other. Names with triple underscore are referred to as + * "flavors" and are useful, among other things, to allow to + * specify/support incompatible variations of the same kernel struct, which + * might differ between different kernel versions and/or build + * configurations. + * + * N.B. Struct "flavors" could be generated by bpftool's BTF-to-C + * converter, when deduplicated BTF of a kernel still contains more than + * one different types with the same name. In that case, ___2, ___3, etc + * are appended starting from second name conflict. But start flavors are + * also useful to be defined "locally", in BPF program, to extract same + * data from incompatible changes between different kernel + * versions/configurations. For instance, to handle field renames between + * kernel versions, one can use two flavors of the struct name with the + * same common name and use conditional relocations to extract that field, + * depending on target kernel version. + * 2. For each candidate type, try to match local specification to this + * candidate target type. Matching involves finding corresponding + * high-level spec accessors, meaning that all named fields should match, + * as well as all array accesses should be within the actual bounds. Also, + * types should be compatible (see bpf_core_fields_are_compat for details). + * 3. It is supported and expected that there might be multiple flavors + * matching the spec. As long as all the specs resolve to the same set of + * offsets across all candidates, there is no error. If there is any + * ambiguity, CO-RE relocation will fail. This is necessary to accomodate + * imprefection of BTF deduplication, which can cause slight duplication of + * the same BTF type, if some directly or indirectly referenced (by + * pointer) type gets resolved to different actual types in different + * object files. If such situation occurs, deduplicated BTF will end up + * with two (or more) structurally identical types, which differ only in + * types they refer to through pointer. This should be OK in most cases and + * is not an error. + * 4. Candidate types search is performed by linearly scanning through all + * types in target BTF. It is anticipated that this is overall more + * efficient memory-wise and not significantly worse (if not better) + * CPU-wise compared to prebuilding a map from all local type names to + * a list of candidate type names. It's also sped up by caching resolved + * list of matching candidates per each local "root" type ID, that has at + * least one bpf_core_relo associated with it. This list is shared + * between multiple relocations for the same type ID and is updated as some + * of the candidates are pruned due to structural incompatibility. + */ +static int bpf_core_apply_relo(struct bpf_program *prog, + const struct bpf_core_relo *relo, + int relo_idx, + const struct btf *local_btf, + const struct btf *targ_btf, + struct hashmap *cand_cache) +{ + struct bpf_core_spec local_spec, cand_spec, targ_spec = {}; + const void *type_key = u32_as_hash_key(relo->type_id); + struct bpf_core_relo_res cand_res, targ_res; + const struct btf_type *local_type; + const char *local_name; + struct ids_vec *cand_ids; + __u32 local_id, cand_id; + const char *spec_str; + int i, j, err; + + local_id = relo->type_id; + local_type = btf__type_by_id(local_btf, local_id); + if (!local_type) + return -EINVAL; + + local_name = btf__name_by_offset(local_btf, local_type->name_off); + if (!local_name) + return -EINVAL; + + spec_str = btf__name_by_offset(local_btf, relo->access_str_off); + if (str_is_empty(spec_str)) + return -EINVAL; + + err = bpf_core_parse_spec(local_btf, local_id, spec_str, relo->kind, &local_spec); + if (err) { + pr_warn("prog '%s': relo #%d: parsing [%d] %s %s + %s failed: %d\n", + prog->name, relo_idx, local_id, btf_kind_str(local_type), + str_is_empty(local_name) ? "<anon>" : local_name, + spec_str, err); + return -EINVAL; + } + + pr_debug("prog '%s': relo #%d: kind <%s> (%d), spec is ", prog->name, + relo_idx, core_relo_kind_str(relo->kind), relo->kind); + bpf_core_dump_spec(LIBBPF_DEBUG, &local_spec); + libbpf_print(LIBBPF_DEBUG, "\n"); + + /* TYPE_ID_LOCAL relo is special and doesn't need candidate search */ + if (relo->kind == BPF_TYPE_ID_LOCAL) { + targ_res.validate = true; + targ_res.poison = false; + targ_res.orig_val = local_spec.root_type_id; + targ_res.new_val = local_spec.root_type_id; + goto patch_insn; + } + + /* libbpf doesn't support candidate search for anonymous types */ + if (str_is_empty(spec_str)) { + pr_warn("prog '%s': relo #%d: <%s> (%d) relocation doesn't support anonymous types\n", + prog->name, relo_idx, core_relo_kind_str(relo->kind), relo->kind); + return -EOPNOTSUPP; + } + + if (!hashmap__find(cand_cache, type_key, (void **)&cand_ids)) { + cand_ids = bpf_core_find_cands(local_btf, local_id, targ_btf); + if (IS_ERR(cand_ids)) { + pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld", + prog->name, relo_idx, local_id, btf_kind_str(local_type), + local_name, PTR_ERR(cand_ids)); + return PTR_ERR(cand_ids); + } + err = hashmap__set(cand_cache, type_key, cand_ids, NULL, NULL); + if (err) { + bpf_core_free_cands(cand_ids); + return err; + } + } + + for (i = 0, j = 0; i < cand_ids->len; i++) { + cand_id = cand_ids->data[i]; + err = bpf_core_spec_match(&local_spec, targ_btf, cand_id, &cand_spec); + if (err < 0) { + pr_warn("prog '%s': relo #%d: error matching candidate #%d ", + prog->name, relo_idx, i); + bpf_core_dump_spec(LIBBPF_WARN, &cand_spec); + libbpf_print(LIBBPF_WARN, ": %d\n", err); + return err; + } + + pr_debug("prog '%s': relo #%d: %s candidate #%d ", prog->name, + relo_idx, err == 0 ? "non-matching" : "matching", i); + bpf_core_dump_spec(LIBBPF_DEBUG, &cand_spec); + libbpf_print(LIBBPF_DEBUG, "\n"); + + if (err == 0) + continue; + + err = bpf_core_calc_relo(prog, relo, relo_idx, &local_spec, &cand_spec, &cand_res); + if (err) + return err; + + if (j == 0) { + targ_res = cand_res; + targ_spec = cand_spec; + } else if (cand_spec.bit_offset != targ_spec.bit_offset) { + /* if there are many field relo candidates, they + * should all resolve to the same bit offset + */ + pr_warn("prog '%s': relo #%d: field offset ambiguity: %u != %u\n", + prog->name, relo_idx, cand_spec.bit_offset, + targ_spec.bit_offset); + return -EINVAL; + } else if (cand_res.poison != targ_res.poison || cand_res.new_val != targ_res.new_val) { + /* all candidates should result in the same relocation + * decision and value, otherwise it's dangerous to + * proceed due to ambiguity + */ + pr_warn("prog '%s': relo #%d: relocation decision ambiguity: %s %u != %s %u\n", + prog->name, relo_idx, + cand_res.poison ? "failure" : "success", cand_res.new_val, + targ_res.poison ? "failure" : "success", targ_res.new_val); + return -EINVAL; + } + + cand_ids->data[j++] = cand_spec.root_type_id; + } + + /* + * For BPF_FIELD_EXISTS relo or when used BPF program has field + * existence checks or kernel version/config checks, it's expected + * that we might not find any candidates. In this case, if field + * wasn't found in any candidate, the list of candidates shouldn't + * change at all, we'll just handle relocating appropriately, + * depending on relo's kind. + */ + if (j > 0) + cand_ids->len = j; + + /* + * If no candidates were found, it might be both a programmer error, + * as well as expected case, depending whether instruction w/ + * relocation is guarded in some way that makes it unreachable (dead + * code) if relocation can't be resolved. This is handled in + * bpf_core_patch_insn() uniformly by replacing that instruction with + * BPF helper call insn (using invalid helper ID). If that instruction + * is indeed unreachable, then it will be ignored and eliminated by + * verifier. If it was an error, then verifier will complain and point + * to a specific instruction number in its log. + */ + if (j == 0) { + pr_debug("prog '%s': relo #%d: no matching targets found\n", + prog->name, relo_idx); + + /* calculate single target relo result explicitly */ + err = bpf_core_calc_relo(prog, relo, relo_idx, &local_spec, NULL, &targ_res); + if (err) + return err; + } + +patch_insn: + /* bpf_core_patch_insn() should know how to handle missing targ_spec */ + err = bpf_core_patch_insn(prog, relo, relo_idx, &targ_res); + if (err) { + pr_warn("prog '%s': relo #%d: failed to patch insn at offset %d: %d\n", + prog->name, relo_idx, relo->insn_off, err); + return -EINVAL; + } + + return 0; +} + +static int +bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) +{ + const struct btf_ext_info_sec *sec; + const struct bpf_core_relo *rec; + const struct btf_ext_info *seg; + struct hashmap_entry *entry; + struct hashmap *cand_cache = NULL; + struct bpf_program *prog; + struct btf *targ_btf; + const char *sec_name; + int i, err = 0, insn_idx, sec_idx; + + if (obj->btf_ext->core_relo_info.len == 0) + return 0; + + if (targ_btf_path) + targ_btf = btf__parse(targ_btf_path, NULL); + else + targ_btf = obj->btf_vmlinux; + if (IS_ERR_OR_NULL(targ_btf)) { + pr_warn("failed to get target BTF: %ld\n", PTR_ERR(targ_btf)); + return PTR_ERR(targ_btf); + } + + cand_cache = hashmap__new(bpf_core_hash_fn, bpf_core_equal_fn, NULL); + if (IS_ERR(cand_cache)) { + err = PTR_ERR(cand_cache); + goto out; + } + + seg = &obj->btf_ext->core_relo_info; + for_each_btf_ext_sec(seg, sec) { + sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off); + if (str_is_empty(sec_name)) { + err = -EINVAL; + goto out; + } + /* bpf_object's ELF is gone by now so it's not easy to find + * section index by section name, but we can find *any* + * bpf_program within desired section name and use it's + * prog->sec_idx to do a proper search by section index and + * instruction offset + */ + prog = NULL; + for (i = 0; i < obj->nr_programs; i++) { + if (strcmp(obj->programs[i].sec_name, sec_name) == 0) { + prog = &obj->programs[i]; + break; + } + } + if (!prog) { + pr_warn("sec '%s': failed to find a BPF program\n", sec_name); + return -ENOENT; + } + sec_idx = prog->sec_idx; + + pr_debug("sec '%s': found %d CO-RE relocations\n", + sec_name, sec->num_info); + + for_each_btf_ext_rec(seg, sec, i, rec) { + insn_idx = rec->insn_off / BPF_INSN_SZ; + prog = find_prog_by_sec_insn(obj, sec_idx, insn_idx); + if (!prog) { + /* When __weak subprog is "overridden" by another instance + * of the subprog from a different object file, linker still + * appends all the .BTF.ext info that used to belong to that + * eliminated subprogram. + * This is similar to what x86-64 linker does for relocations. + * So just ignore such relocations just like we ignore + * subprog instructions when discovering subprograms. + */ + pr_debug("sec '%s': skipping CO-RE relocation #%d for insn #%d belonging to eliminated weak subprogram\n", + sec_name, i, insn_idx); + continue; + } + /* no need to apply CO-RE relocation if the program is + * not going to be loaded + */ + if (!prog->load) + continue; + + err = bpf_core_apply_relo(prog, rec, i, obj->btf, + targ_btf, cand_cache); + if (err) { + pr_warn("prog '%s': relo #%d: failed to relocate: %d\n", + prog->name, i, err); + goto out; + } + } + } + +out: + /* obj->btf_vmlinux is freed at the end of object load phase */ + if (targ_btf != obj->btf_vmlinux) + btf__free(targ_btf); + if (!IS_ERR_OR_NULL(cand_cache)) { + hashmap__for_each_entry(cand_cache, entry, i) { + bpf_core_free_cands(entry->value); + } + hashmap__free(cand_cache); + } + return err; +} + +/* Relocate data references within program code: + * - map references; + * - global variable references; + * - extern references. + */ +static int +bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog) +{ + int i; + + for (i = 0; i < prog->nr_reloc; i++) { + struct reloc_desc *relo = &prog->reloc_desc[i]; + struct bpf_insn *insn = &prog->insns[relo->insn_idx]; + struct extern_desc *ext; + + switch (relo->type) { + case RELO_LD64: + insn[0].src_reg = BPF_PSEUDO_MAP_FD; + insn[0].imm = obj->maps[relo->map_idx].fd; + relo->processed = true; + break; + case RELO_DATA: + insn[0].src_reg = BPF_PSEUDO_MAP_VALUE; + insn[1].imm = insn[0].imm + relo->sym_off; + insn[0].imm = obj->maps[relo->map_idx].fd; + relo->processed = true; + break; + case RELO_EXTERN: + ext = &obj->externs[relo->sym_off]; + if (ext->type == EXT_KCFG) { + insn[0].src_reg = BPF_PSEUDO_MAP_VALUE; + insn[0].imm = obj->maps[obj->kconfig_map_idx].fd; + insn[1].imm = ext->kcfg.data_off; + } else /* EXT_KSYM */ { + if (ext->ksym.type_id) { /* typed ksyms */ + insn[0].src_reg = BPF_PSEUDO_BTF_ID; + insn[0].imm = ext->ksym.vmlinux_btf_id; + } else { /* typeless ksyms */ + insn[0].imm = (__u32)ext->ksym.addr; + insn[1].imm = ext->ksym.addr >> 32; + } + } + relo->processed = true; + break; + case RELO_CALL: + /* will be handled as a follow up pass */ + break; + default: + pr_warn("prog '%s': relo #%d: bad relo type %d\n", + prog->name, i, relo->type); + return -EINVAL; + } + } + + return 0; +} + +static int adjust_prog_btf_ext_info(const struct bpf_object *obj, + const struct bpf_program *prog, + const struct btf_ext_info *ext_info, + void **prog_info, __u32 *prog_rec_cnt, + __u32 *prog_rec_sz) +{ + void *copy_start = NULL, *copy_end = NULL; + void *rec, *rec_end, *new_prog_info; + const struct btf_ext_info_sec *sec; + size_t old_sz, new_sz; + const char *sec_name; + int i, off_adj; + + for_each_btf_ext_sec(ext_info, sec) { + sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off); + if (!sec_name) + return -EINVAL; + if (strcmp(sec_name, prog->sec_name) != 0) + continue; + + for_each_btf_ext_rec(ext_info, sec, i, rec) { + __u32 insn_off = *(__u32 *)rec / BPF_INSN_SZ; + + if (insn_off < prog->sec_insn_off) + continue; + if (insn_off >= prog->sec_insn_off + prog->sec_insn_cnt) + break; + + if (!copy_start) + copy_start = rec; + copy_end = rec + ext_info->rec_size; + } + + if (!copy_start) + return -ENOENT; + + /* append func/line info of a given (sub-)program to the main + * program func/line info + */ + old_sz = (size_t)(*prog_rec_cnt) * ext_info->rec_size; + new_sz = old_sz + (copy_end - copy_start); + new_prog_info = realloc(*prog_info, new_sz); + if (!new_prog_info) + return -ENOMEM; + *prog_info = new_prog_info; + *prog_rec_cnt = new_sz / ext_info->rec_size; + memcpy(new_prog_info + old_sz, copy_start, copy_end - copy_start); + + /* Kernel instruction offsets are in units of 8-byte + * instructions, while .BTF.ext instruction offsets generated + * by Clang are in units of bytes. So convert Clang offsets + * into kernel offsets and adjust offset according to program + * relocated position. + */ + off_adj = prog->sub_insn_off - prog->sec_insn_off; + rec = new_prog_info + old_sz; + rec_end = new_prog_info + new_sz; + for (; rec < rec_end; rec += ext_info->rec_size) { + __u32 *insn_off = rec; + + *insn_off = *insn_off / BPF_INSN_SZ + off_adj; + } + *prog_rec_sz = ext_info->rec_size; + return 0; + } + + return -ENOENT; +} + +static int +reloc_prog_func_and_line_info(const struct bpf_object *obj, + struct bpf_program *main_prog, + const struct bpf_program *prog) +{ + int err; + + /* no .BTF.ext relocation if .BTF.ext is missing or kernel doesn't + * supprot func/line info + */ + if (!obj->btf_ext || !kernel_supports(FEAT_BTF_FUNC)) + return 0; + + /* only attempt func info relocation if main program's func_info + * relocation was successful + */ + if (main_prog != prog && !main_prog->func_info) + goto line_info; + + err = adjust_prog_btf_ext_info(obj, prog, &obj->btf_ext->func_info, + &main_prog->func_info, + &main_prog->func_info_cnt, + &main_prog->func_info_rec_size); + if (err) { + if (err != -ENOENT) { + pr_warn("prog '%s': error relocating .BTF.ext function info: %d\n", + prog->name, err); + return err; + } + if (main_prog->func_info) { + /* + * Some info has already been found but has problem + * in the last btf_ext reloc. Must have to error out. + */ + pr_warn("prog '%s': missing .BTF.ext function info.\n", prog->name); + return err; + } + /* Have problem loading the very first info. Ignore the rest. */ + pr_warn("prog '%s': missing .BTF.ext function info for the main program, skipping all of .BTF.ext func info.\n", + prog->name); + } + +line_info: + /* don't relocate line info if main program's relocation failed */ + if (main_prog != prog && !main_prog->line_info) + return 0; + + err = adjust_prog_btf_ext_info(obj, prog, &obj->btf_ext->line_info, + &main_prog->line_info, + &main_prog->line_info_cnt, + &main_prog->line_info_rec_size); + if (err) { + if (err != -ENOENT) { + pr_warn("prog '%s': error relocating .BTF.ext line info: %d\n", + prog->name, err); + return err; + } + if (main_prog->line_info) { + /* + * Some info has already been found but has problem + * in the last btf_ext reloc. Must have to error out. + */ + pr_warn("prog '%s': missing .BTF.ext line info.\n", prog->name); + return err; + } + /* Have problem loading the very first info. Ignore the rest. */ + pr_warn("prog '%s': missing .BTF.ext line info for the main program, skipping all of .BTF.ext line info.\n", + prog->name); + } + return 0; +} + +static int cmp_relo_by_insn_idx(const void *key, const void *elem) +{ + size_t insn_idx = *(const size_t *)key; + const struct reloc_desc *relo = elem; + + if (insn_idx == relo->insn_idx) + return 0; + return insn_idx < relo->insn_idx ? -1 : 1; +} + +static struct reloc_desc *find_prog_insn_relo(const struct bpf_program *prog, size_t insn_idx) +{ + return bsearch(&insn_idx, prog->reloc_desc, prog->nr_reloc, + sizeof(*prog->reloc_desc), cmp_relo_by_insn_idx); +} + +static int +bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog, + struct bpf_program *prog) +{ + size_t sub_insn_idx, insn_idx, new_cnt; + struct bpf_program *subprog; + struct bpf_insn *insns, *insn; + struct reloc_desc *relo; + int err; + + err = reloc_prog_func_and_line_info(obj, main_prog, prog); + if (err) + return err; + + for (insn_idx = 0; insn_idx < prog->sec_insn_cnt; insn_idx++) { + insn = &main_prog->insns[prog->sub_insn_off + insn_idx]; + if (!insn_is_subprog_call(insn)) + continue; + + relo = find_prog_insn_relo(prog, insn_idx); + if (relo && relo->type != RELO_CALL) { + pr_warn("prog '%s': unexpected relo for insn #%zu, type %d\n", + prog->name, insn_idx, relo->type); + return -LIBBPF_ERRNO__RELOC; + } + if (relo) { + /* sub-program instruction index is a combination of + * an offset of a symbol pointed to by relocation and + * call instruction's imm field; for global functions, + * call always has imm = -1, but for static functions + * relocation is against STT_SECTION and insn->imm + * points to a start of a static function + */ + sub_insn_idx = relo->sym_off / BPF_INSN_SZ + insn->imm + 1; + } else { + /* if subprogram call is to a static function within + * the same ELF section, there won't be any relocation + * emitted, but it also means there is no additional + * offset necessary, insns->imm is relative to + * instruction's original position within the section + */ + sub_insn_idx = prog->sec_insn_off + insn_idx + insn->imm + 1; + } + + /* we enforce that sub-programs should be in .text section */ + subprog = find_prog_by_sec_insn(obj, obj->efile.text_shndx, sub_insn_idx); + if (!subprog) { + pr_warn("prog '%s': no .text section found yet sub-program call exists\n", + prog->name); + return -LIBBPF_ERRNO__RELOC; + } + + /* if it's the first call instruction calling into this + * subprogram (meaning this subprog hasn't been processed + * yet) within the context of current main program: + * - append it at the end of main program's instructions blog; + * - process is recursively, while current program is put on hold; + * - if that subprogram calls some other not yet processes + * subprogram, same thing will happen recursively until + * there are no more unprocesses subprograms left to append + * and relocate. + */ + if (subprog->sub_insn_off == 0) { + subprog->sub_insn_off = main_prog->insns_cnt; + + new_cnt = main_prog->insns_cnt + subprog->insns_cnt; + insns = libbpf_reallocarray(main_prog->insns, new_cnt, sizeof(*insns)); + if (!insns) { + pr_warn("prog '%s': failed to realloc prog code\n", main_prog->name); + return -ENOMEM; + } + main_prog->insns = insns; + main_prog->insns_cnt = new_cnt; + + memcpy(main_prog->insns + subprog->sub_insn_off, subprog->insns, + subprog->insns_cnt * sizeof(*insns)); + + pr_debug("prog '%s': added %zu insns from sub-prog '%s'\n", + main_prog->name, subprog->insns_cnt, subprog->name); + + err = bpf_object__reloc_code(obj, main_prog, subprog); + if (err) + return err; + } + + /* main_prog->insns memory could have been re-allocated, so + * calculate pointer again + */ + insn = &main_prog->insns[prog->sub_insn_off + insn_idx]; + /* calculate correct instruction position within current main + * prog; each main prog can have a different set of + * subprograms appended (potentially in different order as + * well), so position of any subprog can be different for + * different main programs */ + insn->imm = subprog->sub_insn_off - (prog->sub_insn_off + insn_idx) - 1; + + if (relo) + relo->processed = true; + + pr_debug("prog '%s': insn #%zu relocated, imm %d points to subprog '%s' (now at %zu offset)\n", + prog->name, insn_idx, insn->imm, subprog->name, subprog->sub_insn_off); + } + + return 0; +} + +/* + * Relocate sub-program calls. + * + * Algorithm operates as follows. Each entry-point BPF program (referred to as + * main prog) is processed separately. For each subprog (non-entry functions, + * that can be called from either entry progs or other subprogs) gets their + * sub_insn_off reset to zero. This serves as indicator that this subprogram + * hasn't been yet appended and relocated within current main prog. Once its + * relocated, sub_insn_off will point at the position within current main prog + * where given subprog was appended. This will further be used to relocate all + * the call instructions jumping into this subprog. + * + * We start with main program and process all call instructions. If the call + * is into a subprog that hasn't been processed (i.e., subprog->sub_insn_off + * is zero), subprog instructions are appended at the end of main program's + * instruction array. Then main program is "put on hold" while we recursively + * process newly appended subprogram. If that subprogram calls into another + * subprogram that hasn't been appended, new subprogram is appended again to + * the *main* prog's instructions (subprog's instructions are always left + * untouched, as they need to be in unmodified state for subsequent main progs + * and subprog instructions are always sent only as part of a main prog) and + * the process continues recursively. Once all the subprogs called from a main + * prog or any of its subprogs are appended (and relocated), all their + * positions within finalized instructions array are known, so it's easy to + * rewrite call instructions with correct relative offsets, corresponding to + * desired target subprog. + * + * Its important to realize that some subprogs might not be called from some + * main prog and any of its called/used subprogs. Those will keep their + * subprog->sub_insn_off as zero at all times and won't be appended to current + * main prog and won't be relocated within the context of current main prog. + * They might still be used from other main progs later. + * + * Visually this process can be shown as below. Suppose we have two main + * programs mainA and mainB and BPF object contains three subprogs: subA, + * subB, and subC. mainA calls only subA, mainB calls only subC, but subA and + * subC both call subB: + * + * +--------+ +-------+ + * | v v | + * +--+---+ +--+-+-+ +---+--+ + * | subA | | subB | | subC | + * +--+---+ +------+ +---+--+ + * ^ ^ + * | | + * +---+-------+ +------+----+ + * | mainA | | mainB | + * +-----------+ +-----------+ + * + * We'll start relocating mainA, will find subA, append it and start + * processing sub A recursively: + * + * +-----------+------+ + * | mainA | subA | + * +-----------+------+ + * + * At this point we notice that subB is used from subA, so we append it and + * relocate (there are no further subcalls from subB): + * + * +-----------+------+------+ + * | mainA | subA | subB | + * +-----------+------+------+ + * + * At this point, we relocate subA calls, then go one level up and finish with + * relocatin mainA calls. mainA is done. + * + * For mainB process is similar but results in different order. We start with + * mainB and skip subA and subB, as mainB never calls them (at least + * directly), but we see subC is needed, so we append and start processing it: + * + * +-----------+------+ + * | mainB | subC | + * +-----------+------+ + * Now we see subC needs subB, so we go back to it, append and relocate it: + * + * +-----------+------+------+ + * | mainB | subC | subB | + * +-----------+------+------+ + * + * At this point we unwind recursion, relocate calls in subC, then in mainB. + */ +static int +bpf_object__relocate_calls(struct bpf_object *obj, struct bpf_program *prog) +{ + struct bpf_program *subprog; + int i, j, err; + + /* mark all subprogs as not relocated (yet) within the context of + * current main program + */ + for (i = 0; i < obj->nr_programs; i++) { + subprog = &obj->programs[i]; + if (!prog_is_subprog(obj, subprog)) + continue; + + subprog->sub_insn_off = 0; + for (j = 0; j < subprog->nr_reloc; j++) + if (subprog->reloc_desc[j].type == RELO_CALL) + subprog->reloc_desc[j].processed = false; + } + + err = bpf_object__reloc_code(obj, prog, prog); + if (err) + return err; + + + return 0; +} + +static int +bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) +{ + struct bpf_program *prog; + size_t i; + int err; + + if (obj->btf_ext) { + err = bpf_object__relocate_core(obj, targ_btf_path); + if (err) { + pr_warn("failed to perform CO-RE relocations: %d\n", + err); + return err; + } + } + /* relocate data references first for all programs and sub-programs, + * as they don't change relative to code locations, so subsequent + * subprogram processing won't need to re-calculate any of them + */ + for (i = 0; i < obj->nr_programs; i++) { + prog = &obj->programs[i]; + err = bpf_object__relocate_data(obj, prog); + if (err) { + pr_warn("prog '%s': failed to relocate data references: %d\n", + prog->name, err); + return err; + } + } + /* now relocate subprogram calls and append used subprograms to main + * programs; each copy of subprogram code needs to be relocated + * differently for each main program, because its code location might + * have changed + */ + for (i = 0; i < obj->nr_programs; i++) { + prog = &obj->programs[i]; + /* sub-program's sub-calls are relocated within the context of + * its main program only + */ + if (prog_is_subprog(obj, prog)) + continue; + + err = bpf_object__relocate_calls(obj, prog); + if (err) { + pr_warn("prog '%s': failed to relocate calls: %d\n", + prog->name, err); + return err; + } + } + /* free up relocation descriptors */ + for (i = 0; i < obj->nr_programs; i++) { + prog = &obj->programs[i]; + zfree(&prog->reloc_desc); + prog->nr_reloc = 0; + } + return 0; +} + +static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, + GElf_Shdr *shdr, Elf_Data *data); + +static int bpf_object__collect_map_relos(struct bpf_object *obj, + GElf_Shdr *shdr, Elf_Data *data) +{ + const int bpf_ptr_sz = 8, host_ptr_sz = sizeof(void *); + int i, j, nrels, new_sz; + const struct btf_var_secinfo *vi = NULL; + const struct btf_type *sec, *var, *def; + struct bpf_map *map = NULL, *targ_map; + const struct btf_member *member; + const char *name, *mname; + Elf_Data *symbols; + unsigned int moff; + GElf_Sym sym; + GElf_Rel rel; + void *tmp; + + if (!obj->efile.btf_maps_sec_btf_id || !obj->btf) + return -EINVAL; + sec = btf__type_by_id(obj->btf, obj->efile.btf_maps_sec_btf_id); + if (!sec) + return -EINVAL; + + symbols = obj->efile.symbols; + nrels = shdr->sh_size / shdr->sh_entsize; + for (i = 0; i < nrels; i++) { + if (!gelf_getrel(data, i, &rel)) { + pr_warn(".maps relo #%d: failed to get ELF relo\n", i); + return -LIBBPF_ERRNO__FORMAT; + } + if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) { + pr_warn(".maps relo #%d: symbol %zx not found\n", + i, (size_t)GELF_R_SYM(rel.r_info)); + return -LIBBPF_ERRNO__FORMAT; + } + name = elf_sym_str(obj, sym.st_name) ?: "<?>"; + if (sym.st_shndx != obj->efile.btf_maps_shndx) { + pr_warn(".maps relo #%d: '%s' isn't a BTF-defined map\n", + i, name); + return -LIBBPF_ERRNO__RELOC; + } + + pr_debug(".maps relo #%d: for %zd value %zd rel.r_offset %zu name %d ('%s')\n", + i, (ssize_t)(rel.r_info >> 32), (size_t)sym.st_value, + (size_t)rel.r_offset, sym.st_name, name); + + for (j = 0; j < obj->nr_maps; j++) { + map = &obj->maps[j]; + if (map->sec_idx != obj->efile.btf_maps_shndx) + continue; + + vi = btf_var_secinfos(sec) + map->btf_var_idx; + if (vi->offset <= rel.r_offset && + rel.r_offset + bpf_ptr_sz <= vi->offset + vi->size) + break; + } + if (j == obj->nr_maps) { + pr_warn(".maps relo #%d: cannot find map '%s' at rel.r_offset %zu\n", + i, name, (size_t)rel.r_offset); + return -EINVAL; + } + + if (!bpf_map_type__is_map_in_map(map->def.type)) + return -EINVAL; + if (map->def.type == BPF_MAP_TYPE_HASH_OF_MAPS && + map->def.key_size != sizeof(int)) { + pr_warn(".maps relo #%d: hash-of-maps '%s' should have key size %zu.\n", + i, map->name, sizeof(int)); + return -EINVAL; + } + + targ_map = bpf_object__find_map_by_name(obj, name); + if (!targ_map) + return -ESRCH; + + var = btf__type_by_id(obj->btf, vi->type); + def = skip_mods_and_typedefs(obj->btf, var->type, NULL); + if (btf_vlen(def) == 0) + return -EINVAL; + member = btf_members(def) + btf_vlen(def) - 1; + mname = btf__name_by_offset(obj->btf, member->name_off); + if (strcmp(mname, "values")) + return -EINVAL; + + moff = btf_member_bit_offset(def, btf_vlen(def) - 1) / 8; + if (rel.r_offset - vi->offset < moff) + return -EINVAL; + + moff = rel.r_offset - vi->offset - moff; + /* here we use BPF pointer size, which is always 64 bit, as we + * are parsing ELF that was built for BPF target + */ + if (moff % bpf_ptr_sz) + return -EINVAL; + moff /= bpf_ptr_sz; + if (moff >= map->init_slots_sz) { + new_sz = moff + 1; + tmp = libbpf_reallocarray(map->init_slots, new_sz, host_ptr_sz); + if (!tmp) + return -ENOMEM; + map->init_slots = tmp; + memset(map->init_slots + map->init_slots_sz, 0, + (new_sz - map->init_slots_sz) * host_ptr_sz); + map->init_slots_sz = new_sz; + } + map->init_slots[moff] = targ_map; + + pr_debug(".maps relo #%d: map '%s' slot [%d] points to map '%s'\n", + i, map->name, moff, name); + } + + return 0; +} + +static int cmp_relocs(const void *_a, const void *_b) +{ + const struct reloc_desc *a = _a; + const struct reloc_desc *b = _b; + + if (a->insn_idx != b->insn_idx) + return a->insn_idx < b->insn_idx ? -1 : 1; + + /* no two relocations should have the same insn_idx, but ... */ + if (a->type != b->type) + return a->type < b->type ? -1 : 1; + + return 0; +} + +static int bpf_object__collect_relos(struct bpf_object *obj) +{ + int i, err; + + for (i = 0; i < obj->efile.nr_reloc_sects; i++) { + GElf_Shdr *shdr = &obj->efile.reloc_sects[i].shdr; + Elf_Data *data = obj->efile.reloc_sects[i].data; + int idx = shdr->sh_info; + + if (shdr->sh_type != SHT_REL) { + pr_warn("internal error at %d\n", __LINE__); + return -LIBBPF_ERRNO__INTERNAL; + } + + if (idx == obj->efile.st_ops_shndx) + err = bpf_object__collect_st_ops_relos(obj, shdr, data); + else if (idx == obj->efile.btf_maps_shndx) + err = bpf_object__collect_map_relos(obj, shdr, data); + else + err = bpf_object__collect_prog_relos(obj, shdr, data); + if (err) + return err; + } + + for (i = 0; i < obj->nr_programs; i++) { + struct bpf_program *p = &obj->programs[i]; + + if (!p->nr_reloc) + continue; + + qsort(p->reloc_desc, p->nr_reloc, sizeof(*p->reloc_desc), cmp_relocs); + } + return 0; +} + +static bool insn_is_helper_call(struct bpf_insn *insn, enum bpf_func_id *func_id) +{ + if (BPF_CLASS(insn->code) == BPF_JMP && + BPF_OP(insn->code) == BPF_CALL && + BPF_SRC(insn->code) == BPF_K && + insn->src_reg == 0 && + insn->dst_reg == 0) { + *func_id = insn->imm; + return true; + } + return false; +} + +static int bpf_object__sanitize_prog(struct bpf_object* obj, struct bpf_program *prog) +{ + struct bpf_insn *insn = prog->insns; + enum bpf_func_id func_id; + int i; + + for (i = 0; i < prog->insns_cnt; i++, insn++) { + if (!insn_is_helper_call(insn, &func_id)) + continue; + + /* on kernels that don't yet support + * bpf_probe_read_{kernel,user}[_str] helpers, fall back + * to bpf_probe_read() which works well for old kernels + */ + switch (func_id) { + case BPF_FUNC_probe_read_kernel: + case BPF_FUNC_probe_read_user: + if (!kernel_supports(FEAT_PROBE_READ_KERN)) + insn->imm = BPF_FUNC_probe_read; + break; + case BPF_FUNC_probe_read_kernel_str: + case BPF_FUNC_probe_read_user_str: + if (!kernel_supports(FEAT_PROBE_READ_KERN)) + insn->imm = BPF_FUNC_probe_read_str; + break; + default: + break; + } + } + return 0; +} + +static int +load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, + char *license, __u32 kern_version, int *pfd) +{ + struct bpf_load_program_attr load_attr; + char *cp, errmsg[STRERR_BUFSIZE]; + size_t log_buf_size = 0; + char *log_buf = NULL; + int btf_fd, ret; + + if (!insns || !insns_cnt) + return -EINVAL; + + memset(&load_attr, 0, sizeof(struct bpf_load_program_attr)); + load_attr.prog_type = prog->type; + /* old kernels might not support specifying expected_attach_type */ + if (!kernel_supports(FEAT_EXP_ATTACH_TYPE) && prog->sec_def && + prog->sec_def->is_exp_attach_type_optional) + load_attr.expected_attach_type = 0; + else + load_attr.expected_attach_type = prog->expected_attach_type; + if (kernel_supports(FEAT_PROG_NAME)) + load_attr.name = prog->name; + load_attr.insns = insns; + load_attr.insns_cnt = insns_cnt; + load_attr.license = license; + if (prog->type == BPF_PROG_TYPE_STRUCT_OPS || + prog->type == BPF_PROG_TYPE_LSM) { + load_attr.attach_btf_id = prog->attach_btf_id; + } else if (prog->type == BPF_PROG_TYPE_TRACING || + prog->type == BPF_PROG_TYPE_EXT) { + load_attr.attach_prog_fd = prog->attach_prog_fd; + load_attr.attach_btf_id = prog->attach_btf_id; + } else { + load_attr.kern_version = kern_version; + load_attr.prog_ifindex = prog->prog_ifindex; + } + /* specify func_info/line_info only if kernel supports them */ + btf_fd = bpf_object__btf_fd(prog->obj); + if (btf_fd >= 0 && kernel_supports(FEAT_BTF_FUNC)) { + load_attr.prog_btf_fd = btf_fd; + load_attr.func_info = prog->func_info; + load_attr.func_info_rec_size = prog->func_info_rec_size; + load_attr.func_info_cnt = prog->func_info_cnt; + load_attr.line_info = prog->line_info; + load_attr.line_info_rec_size = prog->line_info_rec_size; + load_attr.line_info_cnt = prog->line_info_cnt; + } + load_attr.log_level = prog->log_level; + load_attr.prog_flags = prog->prog_flags; + +retry_load: + if (log_buf_size) { + log_buf = malloc(log_buf_size); + if (!log_buf) + return -ENOMEM; + + *log_buf = 0; + } + + ret = bpf_load_program_xattr(&load_attr, log_buf, log_buf_size); + + if (ret >= 0) { + if (log_buf && load_attr.log_level) + pr_debug("verifier log:\n%s", log_buf); + + if (prog->obj->rodata_map_idx >= 0 && + kernel_supports(FEAT_PROG_BIND_MAP)) { + struct bpf_map *rodata_map = + &prog->obj->maps[prog->obj->rodata_map_idx]; + + if (bpf_prog_bind_map(ret, bpf_map__fd(rodata_map), NULL)) { + cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warn("prog '%s': failed to bind .rodata map: %s\n", + prog->name, cp); + /* Don't fail hard if can't bind rodata. */ + } + } + + *pfd = ret; + ret = 0; + goto out; + } + + if (!log_buf || errno == ENOSPC) { + log_buf_size = max((size_t)BPF_LOG_BUF_SIZE, + log_buf_size << 1); + + free(log_buf); + goto retry_load; + } + ret = errno ? -errno : -LIBBPF_ERRNO__LOAD; + cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warn("load bpf program failed: %s\n", cp); + pr_perm_msg(ret); + + if (log_buf && log_buf[0] != '\0') { + ret = -LIBBPF_ERRNO__VERIFY; + pr_warn("-- BEGIN DUMP LOG ---\n"); + pr_warn("\n%s\n", log_buf); + pr_warn("-- END LOG --\n"); + } else if (load_attr.insns_cnt >= BPF_MAXINSNS) { + pr_warn("Program too large (%zu insns), at most %d insns\n", + load_attr.insns_cnt, BPF_MAXINSNS); + ret = -LIBBPF_ERRNO__PROG2BIG; + } else if (load_attr.prog_type != BPF_PROG_TYPE_KPROBE) { + /* Wrong program type? */ + int fd; + + load_attr.prog_type = BPF_PROG_TYPE_KPROBE; + load_attr.expected_attach_type = 0; + fd = bpf_load_program_xattr(&load_attr, NULL, 0); + if (fd >= 0) { + close(fd); + ret = -LIBBPF_ERRNO__PROGTYPE; + goto out; + } + } + +out: + free(log_buf); + return ret; +} + +static int libbpf_find_attach_btf_id(struct bpf_program *prog); + +int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver) +{ + int err = 0, fd, i, btf_id; + + if (prog->obj->loaded) { + pr_warn("prog '%s': can't load after object was loaded\n", prog->name); + return -EINVAL; + } + + if ((prog->type == BPF_PROG_TYPE_TRACING || + prog->type == BPF_PROG_TYPE_LSM || + prog->type == BPF_PROG_TYPE_EXT) && !prog->attach_btf_id) { + btf_id = libbpf_find_attach_btf_id(prog); + if (btf_id <= 0) + return btf_id; + prog->attach_btf_id = btf_id; + } + + if (prog->instances.nr < 0 || !prog->instances.fds) { + if (prog->preprocessor) { + pr_warn("Internal error: can't load program '%s'\n", + prog->name); + return -LIBBPF_ERRNO__INTERNAL; + } + + prog->instances.fds = malloc(sizeof(int)); + if (!prog->instances.fds) { + pr_warn("Not enough memory for BPF fds\n"); + return -ENOMEM; + } + prog->instances.nr = 1; + prog->instances.fds[0] = -1; + } + + if (!prog->preprocessor) { + if (prog->instances.nr != 1) { + pr_warn("prog '%s': inconsistent nr(%d) != 1\n", + prog->name, prog->instances.nr); + } + err = load_program(prog, prog->insns, prog->insns_cnt, + license, kern_ver, &fd); + if (!err) + prog->instances.fds[0] = fd; + goto out; + } + + for (i = 0; i < prog->instances.nr; i++) { + struct bpf_prog_prep_result result; + bpf_program_prep_t preprocessor = prog->preprocessor; + + memset(&result, 0, sizeof(result)); + err = preprocessor(prog, i, prog->insns, + prog->insns_cnt, &result); + if (err) { + pr_warn("Preprocessing the %dth instance of program '%s' failed\n", + i, prog->name); + goto out; + } + + if (!result.new_insn_ptr || !result.new_insn_cnt) { + pr_debug("Skip loading the %dth instance of program '%s'\n", + i, prog->name); + prog->instances.fds[i] = -1; + if (result.pfd) + *result.pfd = -1; + continue; + } + + err = load_program(prog, result.new_insn_ptr, + result.new_insn_cnt, license, kern_ver, &fd); + if (err) { + pr_warn("Loading the %dth instance of program '%s' failed\n", + i, prog->name); + goto out; + } + + if (result.pfd) + *result.pfd = fd; + prog->instances.fds[i] = fd; + } +out: + if (err) + pr_warn("failed to load program '%s'\n", prog->name); + zfree(&prog->insns); + prog->insns_cnt = 0; + return err; +} + +static int +bpf_object__load_progs(struct bpf_object *obj, int log_level) +{ + struct bpf_program *prog; + size_t i; + int err; + + for (i = 0; i < obj->nr_programs; i++) { + prog = &obj->programs[i]; + err = bpf_object__sanitize_prog(obj, prog); + if (err) + return err; + } + + for (i = 0; i < obj->nr_programs; i++) { + prog = &obj->programs[i]; + if (prog_is_subprog(obj, prog)) + continue; + if (!prog->load) { + pr_debug("prog '%s': skipped loading\n", prog->name); + continue; + } + prog->log_level |= log_level; + err = bpf_program__load(prog, obj->license, obj->kern_version); + if (err) + return err; + } + return 0; +} + +static const struct bpf_sec_def *find_sec_def(const char *sec_name); + +static struct bpf_object * +__bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz, + const struct bpf_object_open_opts *opts) +{ + const char *obj_name, *kconfig; + struct bpf_program *prog; + struct bpf_object *obj; + char tmp_name[64]; + int err; + + if (elf_version(EV_CURRENT) == EV_NONE) { + pr_warn("failed to init libelf for %s\n", + path ? : "(mem buf)"); + return ERR_PTR(-LIBBPF_ERRNO__LIBELF); + } + + if (!OPTS_VALID(opts, bpf_object_open_opts)) + return ERR_PTR(-EINVAL); + + obj_name = OPTS_GET(opts, object_name, NULL); + if (obj_buf) { + if (!obj_name) { + snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx", + (unsigned long)obj_buf, + (unsigned long)obj_buf_sz); + obj_name = tmp_name; + } + path = obj_name; + pr_debug("loading object '%s' from buffer\n", obj_name); + } + + obj = bpf_object__new(path, obj_buf, obj_buf_sz, obj_name); + if (IS_ERR(obj)) + return obj; + + kconfig = OPTS_GET(opts, kconfig, NULL); + if (kconfig) { + obj->kconfig = strdup(kconfig); + if (!obj->kconfig) { + err = -ENOMEM; + goto out; + } + } + + err = bpf_object__elf_init(obj); + err = err ? : bpf_object__check_endianness(obj); + err = err ? : bpf_object__elf_collect(obj); + err = err ? : bpf_object__collect_externs(obj); + err = err ? : bpf_object__finalize_btf(obj); + err = err ? : bpf_object__init_maps(obj, opts); + err = err ? : bpf_object__collect_relos(obj); + if (err) + goto out; + bpf_object__elf_finish(obj); + + bpf_object__for_each_program(prog, obj) { + prog->sec_def = find_sec_def(prog->sec_name); + if (!prog->sec_def) + /* couldn't guess, but user might manually specify */ + continue; + + if (prog->sec_def->is_sleepable) + prog->prog_flags |= BPF_F_SLEEPABLE; + bpf_program__set_type(prog, prog->sec_def->prog_type); + bpf_program__set_expected_attach_type(prog, + prog->sec_def->expected_attach_type); + + if (prog->sec_def->prog_type == BPF_PROG_TYPE_TRACING || + prog->sec_def->prog_type == BPF_PROG_TYPE_EXT) + prog->attach_prog_fd = OPTS_GET(opts, attach_prog_fd, 0); + } + + return obj; +out: + bpf_object__close(obj); + return ERR_PTR(err); +} + +static struct bpf_object * +__bpf_object__open_xattr(struct bpf_object_open_attr *attr, int flags) +{ + DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts, + .relaxed_maps = flags & MAPS_RELAX_COMPAT, + ); + + /* param validation */ + if (!attr->file) + return NULL; + + pr_debug("loading %s\n", attr->file); + return __bpf_object__open(attr->file, NULL, 0, &opts); +} + +struct bpf_object *bpf_object__open_xattr(struct bpf_object_open_attr *attr) +{ + return __bpf_object__open_xattr(attr, 0); +} + +struct bpf_object *bpf_object__open(const char *path) +{ + struct bpf_object_open_attr attr = { + .file = path, + .prog_type = BPF_PROG_TYPE_UNSPEC, + }; + + return bpf_object__open_xattr(&attr); +} + +struct bpf_object * +bpf_object__open_file(const char *path, const struct bpf_object_open_opts *opts) +{ + if (!path) + return ERR_PTR(-EINVAL); + + pr_debug("loading %s\n", path); + + return __bpf_object__open(path, NULL, 0, opts); +} + +struct bpf_object * +bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz, + const struct bpf_object_open_opts *opts) +{ + if (!obj_buf || obj_buf_sz == 0) + return ERR_PTR(-EINVAL); + + return __bpf_object__open(NULL, obj_buf, obj_buf_sz, opts); +} + +struct bpf_object * +bpf_object__open_buffer(const void *obj_buf, size_t obj_buf_sz, + const char *name) +{ + DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts, + .object_name = name, + /* wrong default, but backwards-compatible */ + .relaxed_maps = true, + ); + + /* returning NULL is wrong, but backwards-compatible */ + if (!obj_buf || obj_buf_sz == 0) + return NULL; + + return bpf_object__open_mem(obj_buf, obj_buf_sz, &opts); +} + +int bpf_object__unload(struct bpf_object *obj) +{ + size_t i; + + if (!obj) + return -EINVAL; + + for (i = 0; i < obj->nr_maps; i++) { + zclose(obj->maps[i].fd); + if (obj->maps[i].st_ops) + zfree(&obj->maps[i].st_ops->kern_vdata); + } + + for (i = 0; i < obj->nr_programs; i++) + bpf_program__unload(&obj->programs[i]); + + return 0; +} + +static int bpf_object__sanitize_maps(struct bpf_object *obj) +{ + struct bpf_map *m; + + bpf_object__for_each_map(m, obj) { + if (!bpf_map__is_internal(m)) + continue; + if (!kernel_supports(FEAT_GLOBAL_DATA)) { + pr_warn("kernel doesn't support global data\n"); + return -ENOTSUP; + } + if (!kernel_supports(FEAT_ARRAY_MMAP)) + m->def.map_flags ^= BPF_F_MMAPABLE; + } + + return 0; +} + +static int bpf_object__read_kallsyms_file(struct bpf_object *obj) +{ + char sym_type, sym_name[500]; + unsigned long long sym_addr; + struct extern_desc *ext; + int ret, err = 0; + FILE *f; + + f = fopen("/proc/kallsyms", "r"); + if (!f) { + err = -errno; + pr_warn("failed to open /proc/kallsyms: %d\n", err); + return err; + } + + while (true) { + ret = fscanf(f, "%llx %c %499s%*[^\n]\n", + &sym_addr, &sym_type, sym_name); + if (ret == EOF && feof(f)) + break; + if (ret != 3) { + pr_warn("failed to read kallsyms entry: %d\n", ret); + err = -EINVAL; + goto out; + } + + ext = find_extern_by_name(obj, sym_name); + if (!ext || ext->type != EXT_KSYM) + continue; + + if (ext->is_set && ext->ksym.addr != sym_addr) { + pr_warn("extern (ksym) '%s' resolution is ambiguous: 0x%llx or 0x%llx\n", + sym_name, ext->ksym.addr, sym_addr); + err = -EINVAL; + goto out; + } + if (!ext->is_set) { + ext->is_set = true; + ext->ksym.addr = sym_addr; + pr_debug("extern (ksym) %s=0x%llx\n", sym_name, sym_addr); + } + } + +out: + fclose(f); + return err; +} + +static int bpf_object__resolve_ksyms_btf_id(struct bpf_object *obj) +{ + struct extern_desc *ext; + int i, id; + + for (i = 0; i < obj->nr_extern; i++) { + const struct btf_type *targ_var, *targ_type; + __u32 targ_type_id, local_type_id; + const char *targ_var_name; + int ret; + + ext = &obj->externs[i]; + if (ext->type != EXT_KSYM || !ext->ksym.type_id) + continue; + + id = btf__find_by_name_kind(obj->btf_vmlinux, ext->name, + BTF_KIND_VAR); + if (id <= 0) { + pr_warn("extern (ksym) '%s': failed to find BTF ID in vmlinux BTF.\n", + ext->name); + return -ESRCH; + } + + /* find local type_id */ + local_type_id = ext->ksym.type_id; + + /* find target type_id */ + targ_var = btf__type_by_id(obj->btf_vmlinux, id); + targ_var_name = btf__name_by_offset(obj->btf_vmlinux, + targ_var->name_off); + targ_type = skip_mods_and_typedefs(obj->btf_vmlinux, + targ_var->type, + &targ_type_id); + + ret = bpf_core_types_are_compat(obj->btf, local_type_id, + obj->btf_vmlinux, targ_type_id); + if (ret <= 0) { + const struct btf_type *local_type; + const char *targ_name, *local_name; + + local_type = btf__type_by_id(obj->btf, local_type_id); + local_name = btf__name_by_offset(obj->btf, + local_type->name_off); + targ_name = btf__name_by_offset(obj->btf_vmlinux, + targ_type->name_off); + + pr_warn("extern (ksym) '%s': incompatible types, expected [%d] %s %s, but kernel has [%d] %s %s\n", + ext->name, local_type_id, + btf_kind_str(local_type), local_name, targ_type_id, + btf_kind_str(targ_type), targ_name); + return -EINVAL; + } + + ext->is_set = true; + ext->ksym.vmlinux_btf_id = id; + pr_debug("extern (ksym) '%s': resolved to [%d] %s %s\n", + ext->name, id, btf_kind_str(targ_var), targ_var_name); + } + return 0; +} + +static int bpf_object__resolve_externs(struct bpf_object *obj, + const char *extra_kconfig) +{ + bool need_config = false, need_kallsyms = false; + bool need_vmlinux_btf = false; + struct extern_desc *ext; + void *kcfg_data = NULL; + int err, i; + + if (obj->nr_extern == 0) + return 0; + + if (obj->kconfig_map_idx >= 0) + kcfg_data = obj->maps[obj->kconfig_map_idx].mmaped; + + for (i = 0; i < obj->nr_extern; i++) { + ext = &obj->externs[i]; + + if (ext->type == EXT_KCFG && + strcmp(ext->name, "LINUX_KERNEL_VERSION") == 0) { + void *ext_val = kcfg_data + ext->kcfg.data_off; + __u32 kver = get_kernel_version(); + + if (!kver) { + pr_warn("failed to get kernel version\n"); + return -EINVAL; + } + err = set_kcfg_value_num(ext, ext_val, kver); + if (err) + return err; + pr_debug("extern (kcfg) %s=0x%x\n", ext->name, kver); + } else if (ext->type == EXT_KCFG && + strncmp(ext->name, "CONFIG_", 7) == 0) { + need_config = true; + } else if (ext->type == EXT_KSYM) { + if (ext->ksym.type_id) + need_vmlinux_btf = true; + else + need_kallsyms = true; + } else { + pr_warn("unrecognized extern '%s'\n", ext->name); + return -EINVAL; + } + } + if (need_config && extra_kconfig) { + err = bpf_object__read_kconfig_mem(obj, extra_kconfig, kcfg_data); + if (err) + return -EINVAL; + need_config = false; + for (i = 0; i < obj->nr_extern; i++) { + ext = &obj->externs[i]; + if (ext->type == EXT_KCFG && !ext->is_set) { + need_config = true; + break; + } + } + } + if (need_config) { + err = bpf_object__read_kconfig_file(obj, kcfg_data); + if (err) + return -EINVAL; + } + if (need_kallsyms) { + err = bpf_object__read_kallsyms_file(obj); + if (err) + return -EINVAL; + } + if (need_vmlinux_btf) { + err = bpf_object__resolve_ksyms_btf_id(obj); + if (err) + return -EINVAL; + } + for (i = 0; i < obj->nr_extern; i++) { + ext = &obj->externs[i]; + + if (!ext->is_set && !ext->is_weak) { + pr_warn("extern %s (strong) not resolved\n", ext->name); + return -ESRCH; + } else if (!ext->is_set) { + pr_debug("extern %s (weak) not resolved, defaulting to zero\n", + ext->name); + } + } + + return 0; +} + +int bpf_object__load_xattr(struct bpf_object_load_attr *attr) +{ + struct bpf_object *obj; + int err, i; + + if (!attr) + return -EINVAL; + obj = attr->obj; + if (!obj) + return -EINVAL; + + if (obj->loaded) { + pr_warn("object '%s': load can't be attempted twice\n", obj->name); + return -EINVAL; + } + + err = bpf_object__probe_loading(obj); + err = err ? : bpf_object__load_vmlinux_btf(obj); + err = err ? : bpf_object__resolve_externs(obj, obj->kconfig); + err = err ? : bpf_object__sanitize_and_load_btf(obj); + err = err ? : bpf_object__sanitize_maps(obj); + err = err ? : bpf_object__init_kern_struct_ops_maps(obj); + err = err ? : bpf_object__create_maps(obj); + err = err ? : bpf_object__relocate(obj, attr->target_btf_path); + err = err ? : bpf_object__load_progs(obj, attr->log_level); + + btf__free(obj->btf_vmlinux); + obj->btf_vmlinux = NULL; + + obj->loaded = true; /* doesn't matter if successfully or not */ + + if (err) + goto out; + + return 0; +out: + /* unpin any maps that were auto-pinned during load */ + for (i = 0; i < obj->nr_maps; i++) + if (obj->maps[i].pinned && !obj->maps[i].reused) + bpf_map__unpin(&obj->maps[i], NULL); + + bpf_object__unload(obj); + pr_warn("failed to load object '%s'\n", obj->path); + return err; +} + +int bpf_object__load(struct bpf_object *obj) +{ + struct bpf_object_load_attr attr = { + .obj = obj, + }; + + return bpf_object__load_xattr(&attr); +} + +static int make_parent_dir(const char *path) +{ + char *cp, errmsg[STRERR_BUFSIZE]; + char *dname, *dir; + int err = 0; + + dname = strdup(path); + if (dname == NULL) + return -ENOMEM; + + dir = dirname(dname); + if (mkdir(dir, 0700) && errno != EEXIST) + err = -errno; + + free(dname); + if (err) { + cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg)); + pr_warn("failed to mkdir %s: %s\n", path, cp); + } + return err; +} + +static int check_path(const char *path) +{ + char *cp, errmsg[STRERR_BUFSIZE]; + struct statfs st_fs; + char *dname, *dir; + int err = 0; + + if (path == NULL) + return -EINVAL; + + dname = strdup(path); + if (dname == NULL) + return -ENOMEM; + + dir = dirname(dname); + if (statfs(dir, &st_fs)) { + cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warn("failed to statfs %s: %s\n", dir, cp); + err = -errno; + } + free(dname); + + if (!err && st_fs.f_type != BPF_FS_MAGIC) { + pr_warn("specified path %s is not on BPF FS\n", path); + err = -EINVAL; + } + + return err; +} + +int bpf_program__pin_instance(struct bpf_program *prog, const char *path, + int instance) +{ + char *cp, errmsg[STRERR_BUFSIZE]; + int err; + + err = make_parent_dir(path); + if (err) + return err; + + err = check_path(path); + if (err) + return err; + + if (prog == NULL) { + pr_warn("invalid program pointer\n"); + return -EINVAL; + } + + if (instance < 0 || instance >= prog->instances.nr) { + pr_warn("invalid prog instance %d of prog %s (max %d)\n", + instance, prog->name, prog->instances.nr); + return -EINVAL; + } + + if (bpf_obj_pin(prog->instances.fds[instance], path)) { + err = -errno; + cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); + pr_warn("failed to pin program: %s\n", cp); + return err; + } + pr_debug("pinned program '%s'\n", path); + + return 0; +} + +int bpf_program__unpin_instance(struct bpf_program *prog, const char *path, + int instance) +{ + int err; + + err = check_path(path); + if (err) + return err; + + if (prog == NULL) { + pr_warn("invalid program pointer\n"); + return -EINVAL; + } + + if (instance < 0 || instance >= prog->instances.nr) { + pr_warn("invalid prog instance %d of prog %s (max %d)\n", + instance, prog->name, prog->instances.nr); + return -EINVAL; + } + + err = unlink(path); + if (err != 0) + return -errno; + pr_debug("unpinned program '%s'\n", path); + + return 0; +} + +int bpf_program__pin(struct bpf_program *prog, const char *path) +{ + int i, err; + + err = make_parent_dir(path); + if (err) + return err; + + err = check_path(path); + if (err) + return err; + + if (prog == NULL) { + pr_warn("invalid program pointer\n"); + return -EINVAL; + } + + if (prog->instances.nr <= 0) { + pr_warn("no instances of prog %s to pin\n", prog->name); + return -EINVAL; + } + + if (prog->instances.nr == 1) { + /* don't create subdirs when pinning single instance */ + return bpf_program__pin_instance(prog, path, 0); + } + + for (i = 0; i < prog->instances.nr; i++) { + char buf[PATH_MAX]; + int len; + + len = snprintf(buf, PATH_MAX, "%s/%d", path, i); + if (len < 0) { + err = -EINVAL; + goto err_unpin; + } else if (len >= PATH_MAX) { + err = -ENAMETOOLONG; + goto err_unpin; + } + + err = bpf_program__pin_instance(prog, buf, i); + if (err) + goto err_unpin; + } + + return 0; + +err_unpin: + for (i = i - 1; i >= 0; i--) { + char buf[PATH_MAX]; + int len; + + len = snprintf(buf, PATH_MAX, "%s/%d", path, i); + if (len < 0) + continue; + else if (len >= PATH_MAX) + continue; + + bpf_program__unpin_instance(prog, buf, i); + } + + rmdir(path); + + return err; +} + +int bpf_program__unpin(struct bpf_program *prog, const char *path) +{ + int i, err; + + err = check_path(path); + if (err) + return err; + + if (prog == NULL) { + pr_warn("invalid program pointer\n"); + return -EINVAL; + } + + if (prog->instances.nr <= 0) { + pr_warn("no instances of prog %s to pin\n", prog->name); + return -EINVAL; + } + + if (prog->instances.nr == 1) { + /* don't create subdirs when pinning single instance */ + return bpf_program__unpin_instance(prog, path, 0); + } + + for (i = 0; i < prog->instances.nr; i++) { + char buf[PATH_MAX]; + int len; + + len = snprintf(buf, PATH_MAX, "%s/%d", path, i); + if (len < 0) + return -EINVAL; + else if (len >= PATH_MAX) + return -ENAMETOOLONG; + + err = bpf_program__unpin_instance(prog, buf, i); + if (err) + return err; + } + + err = rmdir(path); + if (err) + return -errno; + + return 0; +} + +int bpf_map__pin(struct bpf_map *map, const char *path) +{ + char *cp, errmsg[STRERR_BUFSIZE]; + int err; + + if (map == NULL) { + pr_warn("invalid map pointer\n"); + return -EINVAL; + } + + if (map->pin_path) { + if (path && strcmp(path, map->pin_path)) { + pr_warn("map '%s' already has pin path '%s' different from '%s'\n", + bpf_map__name(map), map->pin_path, path); + return -EINVAL; + } else if (map->pinned) { + pr_debug("map '%s' already pinned at '%s'; not re-pinning\n", + bpf_map__name(map), map->pin_path); + return 0; + } + } else { + if (!path) { + pr_warn("missing a path to pin map '%s' at\n", + bpf_map__name(map)); + return -EINVAL; + } else if (map->pinned) { + pr_warn("map '%s' already pinned\n", bpf_map__name(map)); + return -EEXIST; + } + + map->pin_path = strdup(path); + if (!map->pin_path) { + err = -errno; + goto out_err; + } + } + + err = make_parent_dir(map->pin_path); + if (err) + return err; + + err = check_path(map->pin_path); + if (err) + return err; + + if (bpf_obj_pin(map->fd, map->pin_path)) { + err = -errno; + goto out_err; + } + + map->pinned = true; + pr_debug("pinned map '%s'\n", map->pin_path); + + return 0; + +out_err: + cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg)); + pr_warn("failed to pin map: %s\n", cp); + return err; +} + +int bpf_map__unpin(struct bpf_map *map, const char *path) +{ + int err; + + if (map == NULL) { + pr_warn("invalid map pointer\n"); + return -EINVAL; + } + + if (map->pin_path) { + if (path && strcmp(path, map->pin_path)) { + pr_warn("map '%s' already has pin path '%s' different from '%s'\n", + bpf_map__name(map), map->pin_path, path); + return -EINVAL; + } + path = map->pin_path; + } else if (!path) { + pr_warn("no path to unpin map '%s' from\n", + bpf_map__name(map)); + return -EINVAL; + } + + err = check_path(path); + if (err) + return err; + + err = unlink(path); + if (err != 0) + return -errno; + + map->pinned = false; + pr_debug("unpinned map '%s' from '%s'\n", bpf_map__name(map), path); + + return 0; +} + +int bpf_map__set_pin_path(struct bpf_map *map, const char *path) +{ + char *new = NULL; + + if (path) { + new = strdup(path); + if (!new) + return -errno; + } + + free(map->pin_path); + map->pin_path = new; + return 0; +} + +const char *bpf_map__get_pin_path(const struct bpf_map *map) +{ + return map->pin_path; +} + +bool bpf_map__is_pinned(const struct bpf_map *map) +{ + return map->pinned; +} + +static void sanitize_pin_path(char *s) +{ + /* bpffs disallows periods in path names */ + while (*s) { + if (*s == '.') + *s = '_'; + s++; + } +} + +int bpf_object__pin_maps(struct bpf_object *obj, const char *path) +{ + struct bpf_map *map; + int err; + + if (!obj) + return -ENOENT; + + if (!obj->loaded) { + pr_warn("object not yet loaded; load it first\n"); + return -ENOENT; + } + + bpf_object__for_each_map(map, obj) { + char *pin_path = NULL; + char buf[PATH_MAX]; + + if (path) { + int len; + + len = snprintf(buf, PATH_MAX, "%s/%s", path, + bpf_map__name(map)); + if (len < 0) { + err = -EINVAL; + goto err_unpin_maps; + } else if (len >= PATH_MAX) { + err = -ENAMETOOLONG; + goto err_unpin_maps; + } + sanitize_pin_path(buf); + pin_path = buf; + } else if (!map->pin_path) { + continue; + } + + err = bpf_map__pin(map, pin_path); + if (err) + goto err_unpin_maps; + } + + return 0; + +err_unpin_maps: + while ((map = bpf_map__prev(map, obj))) { + if (!map->pin_path) + continue; + + bpf_map__unpin(map, NULL); + } + + return err; +} + +int bpf_object__unpin_maps(struct bpf_object *obj, const char *path) +{ + struct bpf_map *map; + int err; + + if (!obj) + return -ENOENT; + + bpf_object__for_each_map(map, obj) { + char *pin_path = NULL; + char buf[PATH_MAX]; + + if (path) { + int len; + + len = snprintf(buf, PATH_MAX, "%s/%s", path, + bpf_map__name(map)); + if (len < 0) + return -EINVAL; + else if (len >= PATH_MAX) + return -ENAMETOOLONG; + sanitize_pin_path(buf); + pin_path = buf; + } else if (!map->pin_path) { + continue; + } + + err = bpf_map__unpin(map, pin_path); + if (err) + return err; + } + + return 0; +} + +int bpf_object__pin_programs(struct bpf_object *obj, const char *path) +{ + struct bpf_program *prog; + int err; + + if (!obj) + return -ENOENT; + + if (!obj->loaded) { + pr_warn("object not yet loaded; load it first\n"); + return -ENOENT; + } + + bpf_object__for_each_program(prog, obj) { + char buf[PATH_MAX]; + int len; + + len = snprintf(buf, PATH_MAX, "%s/%s", path, + prog->pin_name); + if (len < 0) { + err = -EINVAL; + goto err_unpin_programs; + } else if (len >= PATH_MAX) { + err = -ENAMETOOLONG; + goto err_unpin_programs; + } + + err = bpf_program__pin(prog, buf); + if (err) + goto err_unpin_programs; + } + + return 0; + +err_unpin_programs: + while ((prog = bpf_program__prev(prog, obj))) { + char buf[PATH_MAX]; + int len; + + len = snprintf(buf, PATH_MAX, "%s/%s", path, + prog->pin_name); + if (len < 0) + continue; + else if (len >= PATH_MAX) + continue; + + bpf_program__unpin(prog, buf); + } + + return err; +} + +int bpf_object__unpin_programs(struct bpf_object *obj, const char *path) +{ + struct bpf_program *prog; + int err; + + if (!obj) + return -ENOENT; + + bpf_object__for_each_program(prog, obj) { + char buf[PATH_MAX]; + int len; + + len = snprintf(buf, PATH_MAX, "%s/%s", path, + prog->pin_name); + if (len < 0) + return -EINVAL; + else if (len >= PATH_MAX) + return -ENAMETOOLONG; + + err = bpf_program__unpin(prog, buf); + if (err) + return err; + } + + return 0; +} + +int bpf_object__pin(struct bpf_object *obj, const char *path) +{ + int err; + + err = bpf_object__pin_maps(obj, path); + if (err) + return err; + + err = bpf_object__pin_programs(obj, path); + if (err) { + bpf_object__unpin_maps(obj, path); + return err; + } + + return 0; +} + +static void bpf_map__destroy(struct bpf_map *map) +{ + if (map->clear_priv) + map->clear_priv(map, map->priv); + map->priv = NULL; + map->clear_priv = NULL; + + if (map->inner_map) { + bpf_map__destroy(map->inner_map); + zfree(&map->inner_map); + } + + zfree(&map->init_slots); + map->init_slots_sz = 0; + + if (map->mmaped) { + munmap(map->mmaped, bpf_map_mmap_sz(map)); + map->mmaped = NULL; + } + + if (map->st_ops) { + zfree(&map->st_ops->data); + zfree(&map->st_ops->progs); + zfree(&map->st_ops->kern_func_off); + zfree(&map->st_ops); + } + + zfree(&map->name); + zfree(&map->pin_path); + + if (map->fd >= 0) + zclose(map->fd); +} + +void bpf_object__close(struct bpf_object *obj) +{ + size_t i; + + if (IS_ERR_OR_NULL(obj)) + return; + + if (obj->clear_priv) + obj->clear_priv(obj, obj->priv); + + bpf_object__elf_finish(obj); + bpf_object__unload(obj); + btf__free(obj->btf); + btf_ext__free(obj->btf_ext); + + for (i = 0; i < obj->nr_maps; i++) + bpf_map__destroy(&obj->maps[i]); + + zfree(&obj->kconfig); + zfree(&obj->externs); + obj->nr_extern = 0; + + zfree(&obj->maps); + obj->nr_maps = 0; + + if (obj->programs && obj->nr_programs) { + for (i = 0; i < obj->nr_programs; i++) + bpf_program__exit(&obj->programs[i]); + } + zfree(&obj->programs); + + list_del(&obj->list); + free(obj); +} + +struct bpf_object * +bpf_object__next(struct bpf_object *prev) +{ + struct bpf_object *next; + + if (!prev) + next = list_first_entry(&bpf_objects_list, + struct bpf_object, + list); + else + next = list_next_entry(prev, list); + + /* Empty list is noticed here so don't need checking on entry. */ + if (&next->list == &bpf_objects_list) + return NULL; + + return next; +} + +const char *bpf_object__name(const struct bpf_object *obj) +{ + return obj ? obj->name : ERR_PTR(-EINVAL); +} + +unsigned int bpf_object__kversion(const struct bpf_object *obj) +{ + return obj ? obj->kern_version : 0; +} + +struct btf *bpf_object__btf(const struct bpf_object *obj) +{ + return obj ? obj->btf : NULL; +} + +int bpf_object__btf_fd(const struct bpf_object *obj) +{ + return obj->btf ? btf__fd(obj->btf) : -1; +} + +int bpf_object__set_priv(struct bpf_object *obj, void *priv, + bpf_object_clear_priv_t clear_priv) +{ + if (obj->priv && obj->clear_priv) + obj->clear_priv(obj, obj->priv); + + obj->priv = priv; + obj->clear_priv = clear_priv; + return 0; +} + +void *bpf_object__priv(const struct bpf_object *obj) +{ + return obj ? obj->priv : ERR_PTR(-EINVAL); +} + +static struct bpf_program * +__bpf_program__iter(const struct bpf_program *p, const struct bpf_object *obj, + bool forward) +{ + size_t nr_programs = obj->nr_programs; + ssize_t idx; + + if (!nr_programs) + return NULL; + + if (!p) + /* Iter from the beginning */ + return forward ? &obj->programs[0] : + &obj->programs[nr_programs - 1]; + + if (p->obj != obj) { + pr_warn("error: program handler doesn't match object\n"); + return NULL; + } + + idx = (p - obj->programs) + (forward ? 1 : -1); + if (idx >= obj->nr_programs || idx < 0) + return NULL; + return &obj->programs[idx]; +} + +struct bpf_program * +bpf_program__next(struct bpf_program *prev, const struct bpf_object *obj) +{ + struct bpf_program *prog = prev; + + do { + prog = __bpf_program__iter(prog, obj, true); + } while (prog && prog_is_subprog(obj, prog)); + + return prog; +} + +struct bpf_program * +bpf_program__prev(struct bpf_program *next, const struct bpf_object *obj) +{ + struct bpf_program *prog = next; + + do { + prog = __bpf_program__iter(prog, obj, false); + } while (prog && prog_is_subprog(obj, prog)); + + return prog; +} + +int bpf_program__set_priv(struct bpf_program *prog, void *priv, + bpf_program_clear_priv_t clear_priv) +{ + if (prog->priv && prog->clear_priv) + prog->clear_priv(prog, prog->priv); + + prog->priv = priv; + prog->clear_priv = clear_priv; + return 0; +} + +void *bpf_program__priv(const struct bpf_program *prog) +{ + return prog ? prog->priv : ERR_PTR(-EINVAL); +} + +void bpf_program__set_ifindex(struct bpf_program *prog, __u32 ifindex) +{ + prog->prog_ifindex = ifindex; +} + +const char *bpf_program__name(const struct bpf_program *prog) +{ + return prog->name; +} + +const char *bpf_program__section_name(const struct bpf_program *prog) +{ + return prog->sec_name; +} + +const char *bpf_program__title(const struct bpf_program *prog, bool needs_copy) +{ + const char *title; + + title = prog->sec_name; + if (needs_copy) { + title = strdup(title); + if (!title) { + pr_warn("failed to strdup program title\n"); + return ERR_PTR(-ENOMEM); + } + } + + return title; +} + +bool bpf_program__autoload(const struct bpf_program *prog) +{ + return prog->load; +} + +int bpf_program__set_autoload(struct bpf_program *prog, bool autoload) +{ + if (prog->obj->loaded) + return -EINVAL; + + prog->load = autoload; + return 0; +} + +int bpf_program__fd(const struct bpf_program *prog) +{ + return bpf_program__nth_fd(prog, 0); +} + +size_t bpf_program__size(const struct bpf_program *prog) +{ + return prog->insns_cnt * BPF_INSN_SZ; +} + +int bpf_program__set_prep(struct bpf_program *prog, int nr_instances, + bpf_program_prep_t prep) +{ + int *instances_fds; + + if (nr_instances <= 0 || !prep) + return -EINVAL; + + if (prog->instances.nr > 0 || prog->instances.fds) { + pr_warn("Can't set pre-processor after loading\n"); + return -EINVAL; + } + + instances_fds = malloc(sizeof(int) * nr_instances); + if (!instances_fds) { + pr_warn("alloc memory failed for fds\n"); + return -ENOMEM; + } + + /* fill all fd with -1 */ + memset(instances_fds, -1, sizeof(int) * nr_instances); + + prog->instances.nr = nr_instances; + prog->instances.fds = instances_fds; + prog->preprocessor = prep; + return 0; +} + +int bpf_program__nth_fd(const struct bpf_program *prog, int n) +{ + int fd; + + if (!prog) + return -EINVAL; + + if (n >= prog->instances.nr || n < 0) { + pr_warn("Can't get the %dth fd from program %s: only %d instances\n", + n, prog->name, prog->instances.nr); + return -EINVAL; + } + + fd = prog->instances.fds[n]; + if (fd < 0) { + pr_warn("%dth instance of program '%s' is invalid\n", + n, prog->name); + return -ENOENT; + } + + return fd; +} + +enum bpf_prog_type bpf_program__get_type(struct bpf_program *prog) +{ + return prog->type; +} + +void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type) +{ + prog->type = type; +} + +static bool bpf_program__is_type(const struct bpf_program *prog, + enum bpf_prog_type type) +{ + return prog ? (prog->type == type) : false; +} + +#define BPF_PROG_TYPE_FNS(NAME, TYPE) \ +int bpf_program__set_##NAME(struct bpf_program *prog) \ +{ \ + if (!prog) \ + return -EINVAL; \ + bpf_program__set_type(prog, TYPE); \ + return 0; \ +} \ + \ +bool bpf_program__is_##NAME(const struct bpf_program *prog) \ +{ \ + return bpf_program__is_type(prog, TYPE); \ +} \ + +BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER); +BPF_PROG_TYPE_FNS(lsm, BPF_PROG_TYPE_LSM); +BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE); +BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS); +BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT); +BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT); +BPF_PROG_TYPE_FNS(raw_tracepoint, BPF_PROG_TYPE_RAW_TRACEPOINT); +BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP); +BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT); +BPF_PROG_TYPE_FNS(tracing, BPF_PROG_TYPE_TRACING); +BPF_PROG_TYPE_FNS(struct_ops, BPF_PROG_TYPE_STRUCT_OPS); +BPF_PROG_TYPE_FNS(extension, BPF_PROG_TYPE_EXT); +BPF_PROG_TYPE_FNS(sk_lookup, BPF_PROG_TYPE_SK_LOOKUP); + +enum bpf_attach_type +bpf_program__get_expected_attach_type(struct bpf_program *prog) +{ + return prog->expected_attach_type; +} + +void bpf_program__set_expected_attach_type(struct bpf_program *prog, + enum bpf_attach_type type) +{ + prog->expected_attach_type = type; +} + +#define BPF_PROG_SEC_IMPL(string, ptype, eatype, eatype_optional, \ + attachable, attach_btf) \ + { \ + .sec = string, \ + .len = sizeof(string) - 1, \ + .prog_type = ptype, \ + .expected_attach_type = eatype, \ + .is_exp_attach_type_optional = eatype_optional, \ + .is_attachable = attachable, \ + .is_attach_btf = attach_btf, \ + } + +/* Programs that can NOT be attached. */ +#define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 0, 0) + +/* Programs that can be attached. */ +#define BPF_APROG_SEC(string, ptype, atype) \ + BPF_PROG_SEC_IMPL(string, ptype, atype, true, 1, 0) + +/* Programs that must specify expected attach type at load time. */ +#define BPF_EAPROG_SEC(string, ptype, eatype) \ + BPF_PROG_SEC_IMPL(string, ptype, eatype, false, 1, 0) + +/* Programs that use BTF to identify attach point */ +#define BPF_PROG_BTF(string, ptype, eatype) \ + BPF_PROG_SEC_IMPL(string, ptype, eatype, false, 0, 1) + +/* Programs that can be attached but attach type can't be identified by section + * name. Kept for backward compatibility. + */ +#define BPF_APROG_COMPAT(string, ptype) BPF_PROG_SEC(string, ptype) + +#define SEC_DEF(sec_pfx, ptype, ...) { \ + .sec = sec_pfx, \ + .len = sizeof(sec_pfx) - 1, \ + .prog_type = BPF_PROG_TYPE_##ptype, \ + __VA_ARGS__ \ +} + +static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec, + struct bpf_program *prog); +static struct bpf_link *attach_tp(const struct bpf_sec_def *sec, + struct bpf_program *prog); +static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec, + struct bpf_program *prog); +static struct bpf_link *attach_trace(const struct bpf_sec_def *sec, + struct bpf_program *prog); +static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec, + struct bpf_program *prog); +static struct bpf_link *attach_iter(const struct bpf_sec_def *sec, + struct bpf_program *prog); + +static const struct bpf_sec_def section_defs[] = { + BPF_PROG_SEC("socket", BPF_PROG_TYPE_SOCKET_FILTER), + BPF_PROG_SEC("sk_reuseport", BPF_PROG_TYPE_SK_REUSEPORT), + SEC_DEF("kprobe/", KPROBE, + .attach_fn = attach_kprobe), + BPF_PROG_SEC("uprobe/", BPF_PROG_TYPE_KPROBE), + SEC_DEF("kretprobe/", KPROBE, + .attach_fn = attach_kprobe), + BPF_PROG_SEC("uretprobe/", BPF_PROG_TYPE_KPROBE), + BPF_PROG_SEC("classifier", BPF_PROG_TYPE_SCHED_CLS), + BPF_PROG_SEC("action", BPF_PROG_TYPE_SCHED_ACT), + SEC_DEF("tracepoint/", TRACEPOINT, + .attach_fn = attach_tp), + SEC_DEF("tp/", TRACEPOINT, + .attach_fn = attach_tp), + SEC_DEF("raw_tracepoint/", RAW_TRACEPOINT, + .attach_fn = attach_raw_tp), + SEC_DEF("raw_tp/", RAW_TRACEPOINT, + .attach_fn = attach_raw_tp), + SEC_DEF("tp_btf/", TRACING, + .expected_attach_type = BPF_TRACE_RAW_TP, + .is_attach_btf = true, + .attach_fn = attach_trace), + SEC_DEF("fentry/", TRACING, + .expected_attach_type = BPF_TRACE_FENTRY, + .is_attach_btf = true, + .attach_fn = attach_trace), + SEC_DEF("fmod_ret/", TRACING, + .expected_attach_type = BPF_MODIFY_RETURN, + .is_attach_btf = true, + .attach_fn = attach_trace), + SEC_DEF("fexit/", TRACING, + .expected_attach_type = BPF_TRACE_FEXIT, + .is_attach_btf = true, + .attach_fn = attach_trace), + SEC_DEF("fentry.s/", TRACING, + .expected_attach_type = BPF_TRACE_FENTRY, + .is_attach_btf = true, + .is_sleepable = true, + .attach_fn = attach_trace), + SEC_DEF("fmod_ret.s/", TRACING, + .expected_attach_type = BPF_MODIFY_RETURN, + .is_attach_btf = true, + .is_sleepable = true, + .attach_fn = attach_trace), + SEC_DEF("fexit.s/", TRACING, + .expected_attach_type = BPF_TRACE_FEXIT, + .is_attach_btf = true, + .is_sleepable = true, + .attach_fn = attach_trace), + SEC_DEF("freplace/", EXT, + .is_attach_btf = true, + .attach_fn = attach_trace), + SEC_DEF("lsm/", LSM, + .is_attach_btf = true, + .expected_attach_type = BPF_LSM_MAC, + .attach_fn = attach_lsm), + SEC_DEF("lsm.s/", LSM, + .is_attach_btf = true, + .is_sleepable = true, + .expected_attach_type = BPF_LSM_MAC, + .attach_fn = attach_lsm), + SEC_DEF("iter/", TRACING, + .expected_attach_type = BPF_TRACE_ITER, + .is_attach_btf = true, + .attach_fn = attach_iter), + BPF_EAPROG_SEC("xdp_devmap/", BPF_PROG_TYPE_XDP, + BPF_XDP_DEVMAP), + BPF_EAPROG_SEC("xdp_cpumap/", BPF_PROG_TYPE_XDP, + BPF_XDP_CPUMAP), + BPF_APROG_SEC("xdp", BPF_PROG_TYPE_XDP, + BPF_XDP), + BPF_PROG_SEC("perf_event", BPF_PROG_TYPE_PERF_EVENT), + BPF_PROG_SEC("lwt_in", BPF_PROG_TYPE_LWT_IN), + BPF_PROG_SEC("lwt_out", BPF_PROG_TYPE_LWT_OUT), + BPF_PROG_SEC("lwt_xmit", BPF_PROG_TYPE_LWT_XMIT), + BPF_PROG_SEC("lwt_seg6local", BPF_PROG_TYPE_LWT_SEG6LOCAL), + BPF_APROG_SEC("cgroup_skb/ingress", BPF_PROG_TYPE_CGROUP_SKB, + BPF_CGROUP_INET_INGRESS), + BPF_APROG_SEC("cgroup_skb/egress", BPF_PROG_TYPE_CGROUP_SKB, + BPF_CGROUP_INET_EGRESS), + BPF_APROG_COMPAT("cgroup/skb", BPF_PROG_TYPE_CGROUP_SKB), + BPF_EAPROG_SEC("cgroup/sock_create", BPF_PROG_TYPE_CGROUP_SOCK, + BPF_CGROUP_INET_SOCK_CREATE), + BPF_EAPROG_SEC("cgroup/sock_release", BPF_PROG_TYPE_CGROUP_SOCK, + BPF_CGROUP_INET_SOCK_RELEASE), + BPF_APROG_SEC("cgroup/sock", BPF_PROG_TYPE_CGROUP_SOCK, + BPF_CGROUP_INET_SOCK_CREATE), + BPF_EAPROG_SEC("cgroup/post_bind4", BPF_PROG_TYPE_CGROUP_SOCK, + BPF_CGROUP_INET4_POST_BIND), + BPF_EAPROG_SEC("cgroup/post_bind6", BPF_PROG_TYPE_CGROUP_SOCK, + BPF_CGROUP_INET6_POST_BIND), + BPF_APROG_SEC("cgroup/dev", BPF_PROG_TYPE_CGROUP_DEVICE, + BPF_CGROUP_DEVICE), + BPF_APROG_SEC("sockops", BPF_PROG_TYPE_SOCK_OPS, + BPF_CGROUP_SOCK_OPS), + BPF_APROG_SEC("sk_skb/stream_parser", BPF_PROG_TYPE_SK_SKB, + BPF_SK_SKB_STREAM_PARSER), + BPF_APROG_SEC("sk_skb/stream_verdict", BPF_PROG_TYPE_SK_SKB, + BPF_SK_SKB_STREAM_VERDICT), + BPF_APROG_COMPAT("sk_skb", BPF_PROG_TYPE_SK_SKB), + BPF_APROG_SEC("sk_msg", BPF_PROG_TYPE_SK_MSG, + BPF_SK_MSG_VERDICT), + BPF_APROG_SEC("lirc_mode2", BPF_PROG_TYPE_LIRC_MODE2, + BPF_LIRC_MODE2), + BPF_APROG_SEC("flow_dissector", BPF_PROG_TYPE_FLOW_DISSECTOR, + BPF_FLOW_DISSECTOR), + BPF_EAPROG_SEC("cgroup/bind4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, + BPF_CGROUP_INET4_BIND), + BPF_EAPROG_SEC("cgroup/bind6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, + BPF_CGROUP_INET6_BIND), + BPF_EAPROG_SEC("cgroup/connect4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, + BPF_CGROUP_INET4_CONNECT), + BPF_EAPROG_SEC("cgroup/connect6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, + BPF_CGROUP_INET6_CONNECT), + BPF_EAPROG_SEC("cgroup/sendmsg4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, + BPF_CGROUP_UDP4_SENDMSG), + BPF_EAPROG_SEC("cgroup/sendmsg6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, + BPF_CGROUP_UDP6_SENDMSG), + BPF_EAPROG_SEC("cgroup/recvmsg4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, + BPF_CGROUP_UDP4_RECVMSG), + BPF_EAPROG_SEC("cgroup/recvmsg6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, + BPF_CGROUP_UDP6_RECVMSG), + BPF_EAPROG_SEC("cgroup/getpeername4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, + BPF_CGROUP_INET4_GETPEERNAME), + BPF_EAPROG_SEC("cgroup/getpeername6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, + BPF_CGROUP_INET6_GETPEERNAME), + BPF_EAPROG_SEC("cgroup/getsockname4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, + BPF_CGROUP_INET4_GETSOCKNAME), + BPF_EAPROG_SEC("cgroup/getsockname6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, + BPF_CGROUP_INET6_GETSOCKNAME), + BPF_EAPROG_SEC("cgroup/sysctl", BPF_PROG_TYPE_CGROUP_SYSCTL, + BPF_CGROUP_SYSCTL), + BPF_EAPROG_SEC("cgroup/getsockopt", BPF_PROG_TYPE_CGROUP_SOCKOPT, + BPF_CGROUP_GETSOCKOPT), + BPF_EAPROG_SEC("cgroup/setsockopt", BPF_PROG_TYPE_CGROUP_SOCKOPT, + BPF_CGROUP_SETSOCKOPT), + BPF_PROG_SEC("struct_ops", BPF_PROG_TYPE_STRUCT_OPS), + BPF_EAPROG_SEC("sk_lookup/", BPF_PROG_TYPE_SK_LOOKUP, + BPF_SK_LOOKUP), +}; + +#undef BPF_PROG_SEC_IMPL +#undef BPF_PROG_SEC +#undef BPF_APROG_SEC +#undef BPF_EAPROG_SEC +#undef BPF_APROG_COMPAT +#undef SEC_DEF + +#define MAX_TYPE_NAME_SIZE 32 + +static const struct bpf_sec_def *find_sec_def(const char *sec_name) +{ + int i, n = ARRAY_SIZE(section_defs); + + for (i = 0; i < n; i++) { + if (strncmp(sec_name, + section_defs[i].sec, section_defs[i].len)) + continue; + return §ion_defs[i]; + } + return NULL; +} + +static char *libbpf_get_type_names(bool attach_type) +{ + int i, len = ARRAY_SIZE(section_defs) * MAX_TYPE_NAME_SIZE; + char *buf; + + buf = malloc(len); + if (!buf) + return NULL; + + buf[0] = '\0'; + /* Forge string buf with all available names */ + for (i = 0; i < ARRAY_SIZE(section_defs); i++) { + if (attach_type && !section_defs[i].is_attachable) + continue; + + if (strlen(buf) + strlen(section_defs[i].sec) + 2 > len) { + free(buf); + return NULL; + } + strcat(buf, " "); + strcat(buf, section_defs[i].sec); + } + + return buf; +} + +int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type, + enum bpf_attach_type *expected_attach_type) +{ + const struct bpf_sec_def *sec_def; + char *type_names; + + if (!name) + return -EINVAL; + + sec_def = find_sec_def(name); + if (sec_def) { + *prog_type = sec_def->prog_type; + *expected_attach_type = sec_def->expected_attach_type; + return 0; + } + + pr_debug("failed to guess program type from ELF section '%s'\n", name); + type_names = libbpf_get_type_names(false); + if (type_names != NULL) { + pr_debug("supported section(type) names are:%s\n", type_names); + free(type_names); + } + + return -ESRCH; +} + +static struct bpf_map *find_struct_ops_map_by_offset(struct bpf_object *obj, + size_t offset) +{ + struct bpf_map *map; + size_t i; + + for (i = 0; i < obj->nr_maps; i++) { + map = &obj->maps[i]; + if (!bpf_map__is_struct_ops(map)) + continue; + if (map->sec_offset <= offset && + offset - map->sec_offset < map->def.value_size) + return map; + } + + return NULL; +} + +/* Collect the reloc from ELF and populate the st_ops->progs[] */ +static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, + GElf_Shdr *shdr, Elf_Data *data) +{ + const struct btf_member *member; + struct bpf_struct_ops *st_ops; + struct bpf_program *prog; + unsigned int shdr_idx; + const struct btf *btf; + struct bpf_map *map; + Elf_Data *symbols; + unsigned int moff, insn_idx; + const char *name; + __u32 member_idx; + GElf_Sym sym; + GElf_Rel rel; + int i, nrels; + + symbols = obj->efile.symbols; + btf = obj->btf; + nrels = shdr->sh_size / shdr->sh_entsize; + for (i = 0; i < nrels; i++) { + if (!gelf_getrel(data, i, &rel)) { + pr_warn("struct_ops reloc: failed to get %d reloc\n", i); + return -LIBBPF_ERRNO__FORMAT; + } + + if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) { + pr_warn("struct_ops reloc: symbol %zx not found\n", + (size_t)GELF_R_SYM(rel.r_info)); + return -LIBBPF_ERRNO__FORMAT; + } + + name = elf_sym_str(obj, sym.st_name) ?: "<?>"; + map = find_struct_ops_map_by_offset(obj, rel.r_offset); + if (!map) { + pr_warn("struct_ops reloc: cannot find map at rel.r_offset %zu\n", + (size_t)rel.r_offset); + return -EINVAL; + } + + moff = rel.r_offset - map->sec_offset; + shdr_idx = sym.st_shndx; + st_ops = map->st_ops; + pr_debug("struct_ops reloc %s: for %lld value %lld shdr_idx %u rel.r_offset %zu map->sec_offset %zu name %d (\'%s\')\n", + map->name, + (long long)(rel.r_info >> 32), + (long long)sym.st_value, + shdr_idx, (size_t)rel.r_offset, + map->sec_offset, sym.st_name, name); + + if (shdr_idx >= SHN_LORESERVE) { + pr_warn("struct_ops reloc %s: rel.r_offset %zu shdr_idx %u unsupported non-static function\n", + map->name, (size_t)rel.r_offset, shdr_idx); + return -LIBBPF_ERRNO__RELOC; + } + if (sym.st_value % BPF_INSN_SZ) { + pr_warn("struct_ops reloc %s: invalid target program offset %llu\n", + map->name, (unsigned long long)sym.st_value); + return -LIBBPF_ERRNO__FORMAT; + } + insn_idx = sym.st_value / BPF_INSN_SZ; + + member = find_member_by_offset(st_ops->type, moff * 8); + if (!member) { + pr_warn("struct_ops reloc %s: cannot find member at moff %u\n", + map->name, moff); + return -EINVAL; + } + member_idx = member - btf_members(st_ops->type); + name = btf__name_by_offset(btf, member->name_off); + + if (!resolve_func_ptr(btf, member->type, NULL)) { + pr_warn("struct_ops reloc %s: cannot relocate non func ptr %s\n", + map->name, name); + return -EINVAL; + } + + prog = find_prog_by_sec_insn(obj, shdr_idx, insn_idx); + if (!prog) { + pr_warn("struct_ops reloc %s: cannot find prog at shdr_idx %u to relocate func ptr %s\n", + map->name, shdr_idx, name); + return -EINVAL; + } + + if (prog->type == BPF_PROG_TYPE_UNSPEC) { + const struct bpf_sec_def *sec_def; + + sec_def = find_sec_def(prog->sec_name); + if (sec_def && + sec_def->prog_type != BPF_PROG_TYPE_STRUCT_OPS) { + /* for pr_warn */ + prog->type = sec_def->prog_type; + goto invalid_prog; + } + + prog->type = BPF_PROG_TYPE_STRUCT_OPS; + prog->attach_btf_id = st_ops->type_id; + prog->expected_attach_type = member_idx; + } else if (prog->type != BPF_PROG_TYPE_STRUCT_OPS || + prog->attach_btf_id != st_ops->type_id || + prog->expected_attach_type != member_idx) { + goto invalid_prog; + } + st_ops->progs[member_idx] = prog; + } + + return 0; + +invalid_prog: + pr_warn("struct_ops reloc %s: cannot use prog %s in sec %s with type %u attach_btf_id %u expected_attach_type %u for func ptr %s\n", + map->name, prog->name, prog->sec_name, prog->type, + prog->attach_btf_id, prog->expected_attach_type, name); + return -EINVAL; +} + +#define BTF_TRACE_PREFIX "btf_trace_" +#define BTF_LSM_PREFIX "bpf_lsm_" +#define BTF_ITER_PREFIX "bpf_iter_" +#define BTF_MAX_NAME_SIZE 128 + +static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix, + const char *name, __u32 kind) +{ + char btf_type_name[BTF_MAX_NAME_SIZE]; + int ret; + + ret = snprintf(btf_type_name, sizeof(btf_type_name), + "%s%s", prefix, name); + /* snprintf returns the number of characters written excluding the + * the terminating null. So, if >= BTF_MAX_NAME_SIZE are written, it + * indicates truncation. + */ + if (ret < 0 || ret >= sizeof(btf_type_name)) + return -ENAMETOOLONG; + return btf__find_by_name_kind(btf, btf_type_name, kind); +} + +static inline int __find_vmlinux_btf_id(struct btf *btf, const char *name, + enum bpf_attach_type attach_type) +{ + int err; + + if (attach_type == BPF_TRACE_RAW_TP) + err = find_btf_by_prefix_kind(btf, BTF_TRACE_PREFIX, name, + BTF_KIND_TYPEDEF); + else if (attach_type == BPF_LSM_MAC) + err = find_btf_by_prefix_kind(btf, BTF_LSM_PREFIX, name, + BTF_KIND_FUNC); + else if (attach_type == BPF_TRACE_ITER) + err = find_btf_by_prefix_kind(btf, BTF_ITER_PREFIX, name, + BTF_KIND_FUNC); + else + err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC); + + if (err <= 0) + pr_warn("%s is not found in vmlinux BTF\n", name); + + return err; +} + +int libbpf_find_vmlinux_btf_id(const char *name, + enum bpf_attach_type attach_type) +{ + struct btf *btf; + int err; + + btf = libbpf_find_kernel_btf(); + if (IS_ERR(btf)) { + pr_warn("vmlinux BTF is not found\n"); + return -EINVAL; + } + + err = __find_vmlinux_btf_id(btf, name, attach_type); + btf__free(btf); + return err; +} + +static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd) +{ + struct bpf_prog_info_linear *info_linear; + struct bpf_prog_info *info; + struct btf *btf = NULL; + int err = -EINVAL; + + info_linear = bpf_program__get_prog_info_linear(attach_prog_fd, 0); + if (IS_ERR_OR_NULL(info_linear)) { + pr_warn("failed get_prog_info_linear for FD %d\n", + attach_prog_fd); + return -EINVAL; + } + info = &info_linear->info; + if (!info->btf_id) { + pr_warn("The target program doesn't have BTF\n"); + goto out; + } + if (btf__get_from_id(info->btf_id, &btf)) { + pr_warn("Failed to get BTF of the program\n"); + goto out; + } + err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC); + btf__free(btf); + if (err <= 0) { + pr_warn("%s is not found in prog's BTF\n", name); + goto out; + } +out: + free(info_linear); + return err; +} + +static int libbpf_find_attach_btf_id(struct bpf_program *prog) +{ + enum bpf_attach_type attach_type = prog->expected_attach_type; + __u32 attach_prog_fd = prog->attach_prog_fd; + const char *name = prog->sec_name; + int i, err; + + if (!name) + return -EINVAL; + + for (i = 0; i < ARRAY_SIZE(section_defs); i++) { + if (!section_defs[i].is_attach_btf) + continue; + if (strncmp(name, section_defs[i].sec, section_defs[i].len)) + continue; + if (attach_prog_fd) + err = libbpf_find_prog_btf_id(name + section_defs[i].len, + attach_prog_fd); + else + err = __find_vmlinux_btf_id(prog->obj->btf_vmlinux, + name + section_defs[i].len, + attach_type); + return err; + } + pr_warn("failed to identify btf_id based on ELF section name '%s'\n", name); + return -ESRCH; +} + +int libbpf_attach_type_by_name(const char *name, + enum bpf_attach_type *attach_type) +{ + char *type_names; + int i; + + if (!name) + return -EINVAL; + + for (i = 0; i < ARRAY_SIZE(section_defs); i++) { + if (strncmp(name, section_defs[i].sec, section_defs[i].len)) + continue; + if (!section_defs[i].is_attachable) + return -EINVAL; + *attach_type = section_defs[i].expected_attach_type; + return 0; + } + pr_debug("failed to guess attach type based on ELF section name '%s'\n", name); + type_names = libbpf_get_type_names(true); + if (type_names != NULL) { + pr_debug("attachable section(type) names are:%s\n", type_names); + free(type_names); + } + + return -EINVAL; +} + +int bpf_map__fd(const struct bpf_map *map) +{ + return map ? map->fd : -EINVAL; +} + +const struct bpf_map_def *bpf_map__def(const struct bpf_map *map) +{ + return map ? &map->def : ERR_PTR(-EINVAL); +} + +const char *bpf_map__name(const struct bpf_map *map) +{ + return map ? map->name : NULL; +} + +enum bpf_map_type bpf_map__type(const struct bpf_map *map) +{ + return map->def.type; +} + +int bpf_map__set_type(struct bpf_map *map, enum bpf_map_type type) +{ + if (map->fd >= 0) + return -EBUSY; + map->def.type = type; + return 0; +} + +__u32 bpf_map__map_flags(const struct bpf_map *map) +{ + return map->def.map_flags; +} + +int bpf_map__set_map_flags(struct bpf_map *map, __u32 flags) +{ + if (map->fd >= 0) + return -EBUSY; + map->def.map_flags = flags; + return 0; +} + +__u32 bpf_map__numa_node(const struct bpf_map *map) +{ + return map->numa_node; +} + +int bpf_map__set_numa_node(struct bpf_map *map, __u32 numa_node) +{ + if (map->fd >= 0) + return -EBUSY; + map->numa_node = numa_node; + return 0; +} + +__u32 bpf_map__key_size(const struct bpf_map *map) +{ + return map->def.key_size; +} + +int bpf_map__set_key_size(struct bpf_map *map, __u32 size) +{ + if (map->fd >= 0) + return -EBUSY; + map->def.key_size = size; + return 0; +} + +__u32 bpf_map__value_size(const struct bpf_map *map) +{ + return map->def.value_size; +} + +int bpf_map__set_value_size(struct bpf_map *map, __u32 size) +{ + if (map->fd >= 0) + return -EBUSY; + map->def.value_size = size; + return 0; +} + +__u32 bpf_map__btf_key_type_id(const struct bpf_map *map) +{ + return map ? map->btf_key_type_id : 0; +} + +__u32 bpf_map__btf_value_type_id(const struct bpf_map *map) +{ + return map ? map->btf_value_type_id : 0; +} + +int bpf_map__set_priv(struct bpf_map *map, void *priv, + bpf_map_clear_priv_t clear_priv) +{ + if (!map) + return -EINVAL; + + if (map->priv) { + if (map->clear_priv) + map->clear_priv(map, map->priv); + } + + map->priv = priv; + map->clear_priv = clear_priv; + return 0; +} + +void *bpf_map__priv(const struct bpf_map *map) +{ + return map ? map->priv : ERR_PTR(-EINVAL); +} + +int bpf_map__set_initial_value(struct bpf_map *map, + const void *data, size_t size) +{ + if (!map->mmaped || map->libbpf_type == LIBBPF_MAP_KCONFIG || + size != map->def.value_size || map->fd >= 0) + return -EINVAL; + + memcpy(map->mmaped, data, size); + return 0; +} + +bool bpf_map__is_offload_neutral(const struct bpf_map *map) +{ + return map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY; +} + +bool bpf_map__is_internal(const struct bpf_map *map) +{ + return map->libbpf_type != LIBBPF_MAP_UNSPEC; +} + +__u32 bpf_map__ifindex(const struct bpf_map *map) +{ + return map->map_ifindex; +} + +int bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex) +{ + if (map->fd >= 0) + return -EBUSY; + map->map_ifindex = ifindex; + return 0; +} + +int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd) +{ + if (!bpf_map_type__is_map_in_map(map->def.type)) { + pr_warn("error: unsupported map type\n"); + return -EINVAL; + } + if (map->inner_map_fd != -1) { + pr_warn("error: inner_map_fd already specified\n"); + return -EINVAL; + } + map->inner_map_fd = fd; + return 0; +} + +static struct bpf_map * +__bpf_map__iter(const struct bpf_map *m, const struct bpf_object *obj, int i) +{ + ssize_t idx; + struct bpf_map *s, *e; + + if (!obj || !obj->maps) + return NULL; + + s = obj->maps; + e = obj->maps + obj->nr_maps; + + if ((m < s) || (m >= e)) { + pr_warn("error in %s: map handler doesn't belong to object\n", + __func__); + return NULL; + } + + idx = (m - obj->maps) + i; + if (idx >= obj->nr_maps || idx < 0) + return NULL; + return &obj->maps[idx]; +} + +struct bpf_map * +bpf_map__next(const struct bpf_map *prev, const struct bpf_object *obj) +{ + if (prev == NULL) + return obj->maps; + + return __bpf_map__iter(prev, obj, 1); +} + +struct bpf_map * +bpf_map__prev(const struct bpf_map *next, const struct bpf_object *obj) +{ + if (next == NULL) { + if (!obj->nr_maps) + return NULL; + return obj->maps + obj->nr_maps - 1; + } + + return __bpf_map__iter(next, obj, -1); +} + +struct bpf_map * +bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name) +{ + struct bpf_map *pos; + + bpf_object__for_each_map(pos, obj) { + if (pos->name && !strcmp(pos->name, name)) + return pos; + } + return NULL; +} + +int +bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name) +{ + return bpf_map__fd(bpf_object__find_map_by_name(obj, name)); +} + +struct bpf_map * +bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset) +{ + return ERR_PTR(-ENOTSUP); +} + +long libbpf_get_error(const void *ptr) +{ + return PTR_ERR_OR_ZERO(ptr); +} + +int bpf_prog_load(const char *file, enum bpf_prog_type type, + struct bpf_object **pobj, int *prog_fd) +{ + struct bpf_prog_load_attr attr; + + memset(&attr, 0, sizeof(struct bpf_prog_load_attr)); + attr.file = file; + attr.prog_type = type; + attr.expected_attach_type = 0; + + return bpf_prog_load_xattr(&attr, pobj, prog_fd); +} + +int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr, + struct bpf_object **pobj, int *prog_fd) +{ + struct bpf_object_open_attr open_attr = {}; + struct bpf_program *prog, *first_prog = NULL; + struct bpf_object *obj; + struct bpf_map *map; + int err; + + if (!attr) + return -EINVAL; + if (!attr->file) + return -EINVAL; + + open_attr.file = attr->file; + open_attr.prog_type = attr->prog_type; + + obj = bpf_object__open_xattr(&open_attr); + if (IS_ERR_OR_NULL(obj)) + return -ENOENT; + + bpf_object__for_each_program(prog, obj) { + enum bpf_attach_type attach_type = attr->expected_attach_type; + /* + * to preserve backwards compatibility, bpf_prog_load treats + * attr->prog_type, if specified, as an override to whatever + * bpf_object__open guessed + */ + if (attr->prog_type != BPF_PROG_TYPE_UNSPEC) { + bpf_program__set_type(prog, attr->prog_type); + bpf_program__set_expected_attach_type(prog, + attach_type); + } + if (bpf_program__get_type(prog) == BPF_PROG_TYPE_UNSPEC) { + /* + * we haven't guessed from section name and user + * didn't provide a fallback type, too bad... + */ + bpf_object__close(obj); + return -EINVAL; + } + + prog->prog_ifindex = attr->ifindex; + prog->log_level = attr->log_level; + prog->prog_flags |= attr->prog_flags; + if (!first_prog) + first_prog = prog; + } + + bpf_object__for_each_map(map, obj) { + if (!bpf_map__is_offload_neutral(map)) + map->map_ifindex = attr->ifindex; + } + + if (!first_prog) { + pr_warn("object file doesn't contain bpf program\n"); + bpf_object__close(obj); + return -ENOENT; + } + + err = bpf_object__load(obj); + if (err) { + bpf_object__close(obj); + return err; + } + + *pobj = obj; + *prog_fd = bpf_program__fd(first_prog); + return 0; +} + +struct bpf_link { + int (*detach)(struct bpf_link *link); + int (*destroy)(struct bpf_link *link); + char *pin_path; /* NULL, if not pinned */ + int fd; /* hook FD, -1 if not applicable */ + bool disconnected; +}; + +/* Replace link's underlying BPF program with the new one */ +int bpf_link__update_program(struct bpf_link *link, struct bpf_program *prog) +{ + return bpf_link_update(bpf_link__fd(link), bpf_program__fd(prog), NULL); +} + +/* Release "ownership" of underlying BPF resource (typically, BPF program + * attached to some BPF hook, e.g., tracepoint, kprobe, etc). Disconnected + * link, when destructed through bpf_link__destroy() call won't attempt to + * detach/unregisted that BPF resource. This is useful in situations where, + * say, attached BPF program has to outlive userspace program that attached it + * in the system. Depending on type of BPF program, though, there might be + * additional steps (like pinning BPF program in BPF FS) necessary to ensure + * exit of userspace program doesn't trigger automatic detachment and clean up + * inside the kernel. + */ +void bpf_link__disconnect(struct bpf_link *link) +{ + link->disconnected = true; +} + +int bpf_link__destroy(struct bpf_link *link) +{ + int err = 0; + + if (IS_ERR_OR_NULL(link)) + return 0; + + if (!link->disconnected && link->detach) + err = link->detach(link); + if (link->destroy) + link->destroy(link); + if (link->pin_path) + free(link->pin_path); + free(link); + + return err; +} + +int bpf_link__fd(const struct bpf_link *link) +{ + return link->fd; +} + +const char *bpf_link__pin_path(const struct bpf_link *link) +{ + return link->pin_path; +} + +static int bpf_link__detach_fd(struct bpf_link *link) +{ + return close(link->fd); +} + +struct bpf_link *bpf_link__open(const char *path) +{ + struct bpf_link *link; + int fd; + + fd = bpf_obj_get(path); + if (fd < 0) { + fd = -errno; + pr_warn("failed to open link at %s: %d\n", path, fd); + return ERR_PTR(fd); + } + + link = calloc(1, sizeof(*link)); + if (!link) { + close(fd); + return ERR_PTR(-ENOMEM); + } + link->detach = &bpf_link__detach_fd; + link->fd = fd; + + link->pin_path = strdup(path); + if (!link->pin_path) { + bpf_link__destroy(link); + return ERR_PTR(-ENOMEM); + } + + return link; +} + +int bpf_link__detach(struct bpf_link *link) +{ + return bpf_link_detach(link->fd) ? -errno : 0; +} + +int bpf_link__pin(struct bpf_link *link, const char *path) +{ + int err; + + if (link->pin_path) + return -EBUSY; + err = make_parent_dir(path); + if (err) + return err; + err = check_path(path); + if (err) + return err; + + link->pin_path = strdup(path); + if (!link->pin_path) + return -ENOMEM; + + if (bpf_obj_pin(link->fd, link->pin_path)) { + err = -errno; + zfree(&link->pin_path); + return err; + } + + pr_debug("link fd=%d: pinned at %s\n", link->fd, link->pin_path); + return 0; +} + +int bpf_link__unpin(struct bpf_link *link) +{ + int err; + + if (!link->pin_path) + return -EINVAL; + + err = unlink(link->pin_path); + if (err != 0) + return -errno; + + pr_debug("link fd=%d: unpinned from %s\n", link->fd, link->pin_path); + zfree(&link->pin_path); + return 0; +} + +static int bpf_link__detach_perf_event(struct bpf_link *link) +{ + int err; + + err = ioctl(link->fd, PERF_EVENT_IOC_DISABLE, 0); + if (err) + err = -errno; + + close(link->fd); + return err; +} + +struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog, + int pfd) +{ + char errmsg[STRERR_BUFSIZE]; + struct bpf_link *link; + int prog_fd, err; + + if (pfd < 0) { + pr_warn("prog '%s': invalid perf event FD %d\n", + prog->name, pfd); + return ERR_PTR(-EINVAL); + } + prog_fd = bpf_program__fd(prog); + if (prog_fd < 0) { + pr_warn("prog '%s': can't attach BPF program w/o FD (did you load it?)\n", + prog->name); + return ERR_PTR(-EINVAL); + } + + link = calloc(1, sizeof(*link)); + if (!link) + return ERR_PTR(-ENOMEM); + link->detach = &bpf_link__detach_perf_event; + link->fd = pfd; + + if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, prog_fd) < 0) { + err = -errno; + free(link); + pr_warn("prog '%s': failed to attach to pfd %d: %s\n", + prog->name, pfd, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + if (err == -EPROTO) + pr_warn("prog '%s': try add PERF_SAMPLE_CALLCHAIN to or remove exclude_callchain_[kernel|user] from pfd %d\n", + prog->name, pfd); + return ERR_PTR(err); + } + if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) { + err = -errno; + free(link); + pr_warn("prog '%s': failed to enable pfd %d: %s\n", + prog->name, pfd, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + return ERR_PTR(err); + } + return link; +} + +/* + * this function is expected to parse integer in the range of [0, 2^31-1] from + * given file using scanf format string fmt. If actual parsed value is + * negative, the result might be indistinguishable from error + */ +static int parse_uint_from_file(const char *file, const char *fmt) +{ + char buf[STRERR_BUFSIZE]; + int err, ret; + FILE *f; + + f = fopen(file, "r"); + if (!f) { + err = -errno; + pr_debug("failed to open '%s': %s\n", file, + libbpf_strerror_r(err, buf, sizeof(buf))); + return err; + } + err = fscanf(f, fmt, &ret); + if (err != 1) { + err = err == EOF ? -EIO : -errno; + pr_debug("failed to parse '%s': %s\n", file, + libbpf_strerror_r(err, buf, sizeof(buf))); + fclose(f); + return err; + } + fclose(f); + return ret; +} + +static int determine_kprobe_perf_type(void) +{ + const char *file = "/sys/bus/event_source/devices/kprobe/type"; + + return parse_uint_from_file(file, "%d\n"); +} + +static int determine_uprobe_perf_type(void) +{ + const char *file = "/sys/bus/event_source/devices/uprobe/type"; + + return parse_uint_from_file(file, "%d\n"); +} + +static int determine_kprobe_retprobe_bit(void) +{ + const char *file = "/sys/bus/event_source/devices/kprobe/format/retprobe"; + + return parse_uint_from_file(file, "config:%d\n"); +} + +static int determine_uprobe_retprobe_bit(void) +{ + const char *file = "/sys/bus/event_source/devices/uprobe/format/retprobe"; + + return parse_uint_from_file(file, "config:%d\n"); +} + +static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name, + uint64_t offset, int pid) +{ + struct perf_event_attr attr = {}; + char errmsg[STRERR_BUFSIZE]; + int type, pfd, err; + + type = uprobe ? determine_uprobe_perf_type() + : determine_kprobe_perf_type(); + if (type < 0) { + pr_warn("failed to determine %s perf type: %s\n", + uprobe ? "uprobe" : "kprobe", + libbpf_strerror_r(type, errmsg, sizeof(errmsg))); + return type; + } + if (retprobe) { + int bit = uprobe ? determine_uprobe_retprobe_bit() + : determine_kprobe_retprobe_bit(); + + if (bit < 0) { + pr_warn("failed to determine %s retprobe bit: %s\n", + uprobe ? "uprobe" : "kprobe", + libbpf_strerror_r(bit, errmsg, sizeof(errmsg))); + return bit; + } + attr.config |= 1 << bit; + } + attr.size = sizeof(attr); + attr.type = type; + attr.config1 = ptr_to_u64(name); /* kprobe_func or uprobe_path */ + attr.config2 = offset; /* kprobe_addr or probe_offset */ + + /* pid filter is meaningful only for uprobes */ + pfd = syscall(__NR_perf_event_open, &attr, + pid < 0 ? -1 : pid /* pid */, + pid == -1 ? 0 : -1 /* cpu */, + -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC); + if (pfd < 0) { + err = -errno; + pr_warn("%s perf_event_open() failed: %s\n", + uprobe ? "uprobe" : "kprobe", + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + return err; + } + return pfd; +} + +struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog, + bool retprobe, + const char *func_name) +{ + char errmsg[STRERR_BUFSIZE]; + struct bpf_link *link; + int pfd, err; + + pfd = perf_event_open_probe(false /* uprobe */, retprobe, func_name, + 0 /* offset */, -1 /* pid */); + if (pfd < 0) { + pr_warn("prog '%s': failed to create %s '%s' perf event: %s\n", + prog->name, retprobe ? "kretprobe" : "kprobe", func_name, + libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); + return ERR_PTR(pfd); + } + link = bpf_program__attach_perf_event(prog, pfd); + if (IS_ERR(link)) { + close(pfd); + err = PTR_ERR(link); + pr_warn("prog '%s': failed to attach to %s '%s': %s\n", + prog->name, retprobe ? "kretprobe" : "kprobe", func_name, + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + return link; + } + return link; +} + +static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec, + struct bpf_program *prog) +{ + const char *func_name; + bool retprobe; + + func_name = prog->sec_name + sec->len; + retprobe = strcmp(sec->sec, "kretprobe/") == 0; + + return bpf_program__attach_kprobe(prog, retprobe, func_name); +} + +struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog, + bool retprobe, pid_t pid, + const char *binary_path, + size_t func_offset) +{ + char errmsg[STRERR_BUFSIZE]; + struct bpf_link *link; + int pfd, err; + + pfd = perf_event_open_probe(true /* uprobe */, retprobe, + binary_path, func_offset, pid); + if (pfd < 0) { + pr_warn("prog '%s': failed to create %s '%s:0x%zx' perf event: %s\n", + prog->name, retprobe ? "uretprobe" : "uprobe", + binary_path, func_offset, + libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); + return ERR_PTR(pfd); + } + link = bpf_program__attach_perf_event(prog, pfd); + if (IS_ERR(link)) { + close(pfd); + err = PTR_ERR(link); + pr_warn("prog '%s': failed to attach to %s '%s:0x%zx': %s\n", + prog->name, retprobe ? "uretprobe" : "uprobe", + binary_path, func_offset, + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + return link; + } + return link; +} + +static int determine_tracepoint_id(const char *tp_category, + const char *tp_name) +{ + char file[PATH_MAX]; + int ret; + + ret = snprintf(file, sizeof(file), + "/sys/kernel/debug/tracing/events/%s/%s/id", + tp_category, tp_name); + if (ret < 0) + return -errno; + if (ret >= sizeof(file)) { + pr_debug("tracepoint %s/%s path is too long\n", + tp_category, tp_name); + return -E2BIG; + } + return parse_uint_from_file(file, "%d\n"); +} + +static int perf_event_open_tracepoint(const char *tp_category, + const char *tp_name) +{ + struct perf_event_attr attr = {}; + char errmsg[STRERR_BUFSIZE]; + int tp_id, pfd, err; + + tp_id = determine_tracepoint_id(tp_category, tp_name); + if (tp_id < 0) { + pr_warn("failed to determine tracepoint '%s/%s' perf event ID: %s\n", + tp_category, tp_name, + libbpf_strerror_r(tp_id, errmsg, sizeof(errmsg))); + return tp_id; + } + + attr.type = PERF_TYPE_TRACEPOINT; + attr.size = sizeof(attr); + attr.config = tp_id; + + pfd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, 0 /* cpu */, + -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC); + if (pfd < 0) { + err = -errno; + pr_warn("tracepoint '%s/%s' perf_event_open() failed: %s\n", + tp_category, tp_name, + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + return err; + } + return pfd; +} + +struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog, + const char *tp_category, + const char *tp_name) +{ + char errmsg[STRERR_BUFSIZE]; + struct bpf_link *link; + int pfd, err; + + pfd = perf_event_open_tracepoint(tp_category, tp_name); + if (pfd < 0) { + pr_warn("prog '%s': failed to create tracepoint '%s/%s' perf event: %s\n", + prog->name, tp_category, tp_name, + libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); + return ERR_PTR(pfd); + } + link = bpf_program__attach_perf_event(prog, pfd); + if (IS_ERR(link)) { + close(pfd); + err = PTR_ERR(link); + pr_warn("prog '%s': failed to attach to tracepoint '%s/%s': %s\n", + prog->name, tp_category, tp_name, + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + return link; + } + return link; +} + +static struct bpf_link *attach_tp(const struct bpf_sec_def *sec, + struct bpf_program *prog) +{ + char *sec_name, *tp_cat, *tp_name; + struct bpf_link *link; + + sec_name = strdup(prog->sec_name); + if (!sec_name) + return ERR_PTR(-ENOMEM); + + /* extract "tp/<category>/<name>" */ + tp_cat = sec_name + sec->len; + tp_name = strchr(tp_cat, '/'); + if (!tp_name) { + link = ERR_PTR(-EINVAL); + goto out; + } + *tp_name = '\0'; + tp_name++; + + link = bpf_program__attach_tracepoint(prog, tp_cat, tp_name); +out: + free(sec_name); + return link; +} + +struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog, + const char *tp_name) +{ + char errmsg[STRERR_BUFSIZE]; + struct bpf_link *link; + int prog_fd, pfd; + + prog_fd = bpf_program__fd(prog); + if (prog_fd < 0) { + pr_warn("prog '%s': can't attach before loaded\n", prog->name); + return ERR_PTR(-EINVAL); + } + + link = calloc(1, sizeof(*link)); + if (!link) + return ERR_PTR(-ENOMEM); + link->detach = &bpf_link__detach_fd; + + pfd = bpf_raw_tracepoint_open(tp_name, prog_fd); + if (pfd < 0) { + pfd = -errno; + free(link); + pr_warn("prog '%s': failed to attach to raw tracepoint '%s': %s\n", + prog->name, tp_name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); + return ERR_PTR(pfd); + } + link->fd = pfd; + return link; +} + +static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec, + struct bpf_program *prog) +{ + const char *tp_name = prog->sec_name + sec->len; + + return bpf_program__attach_raw_tracepoint(prog, tp_name); +} + +/* Common logic for all BPF program types that attach to a btf_id */ +static struct bpf_link *bpf_program__attach_btf_id(struct bpf_program *prog) +{ + char errmsg[STRERR_BUFSIZE]; + struct bpf_link *link; + int prog_fd, pfd; + + prog_fd = bpf_program__fd(prog); + if (prog_fd < 0) { + pr_warn("prog '%s': can't attach before loaded\n", prog->name); + return ERR_PTR(-EINVAL); + } + + link = calloc(1, sizeof(*link)); + if (!link) + return ERR_PTR(-ENOMEM); + link->detach = &bpf_link__detach_fd; + + pfd = bpf_raw_tracepoint_open(NULL, prog_fd); + if (pfd < 0) { + pfd = -errno; + free(link); + pr_warn("prog '%s': failed to attach: %s\n", + prog->name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); + return ERR_PTR(pfd); + } + link->fd = pfd; + return (struct bpf_link *)link; +} + +struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog) +{ + return bpf_program__attach_btf_id(prog); +} + +struct bpf_link *bpf_program__attach_lsm(struct bpf_program *prog) +{ + return bpf_program__attach_btf_id(prog); +} + +static struct bpf_link *attach_trace(const struct bpf_sec_def *sec, + struct bpf_program *prog) +{ + return bpf_program__attach_trace(prog); +} + +static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec, + struct bpf_program *prog) +{ + return bpf_program__attach_lsm(prog); +} + +static struct bpf_link *attach_iter(const struct bpf_sec_def *sec, + struct bpf_program *prog) +{ + return bpf_program__attach_iter(prog, NULL); +} + +static struct bpf_link * +bpf_program__attach_fd(struct bpf_program *prog, int target_fd, int btf_id, + const char *target_name) +{ + DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts, + .target_btf_id = btf_id); + enum bpf_attach_type attach_type; + char errmsg[STRERR_BUFSIZE]; + struct bpf_link *link; + int prog_fd, link_fd; + + prog_fd = bpf_program__fd(prog); + if (prog_fd < 0) { + pr_warn("prog '%s': can't attach before loaded\n", prog->name); + return ERR_PTR(-EINVAL); + } + + link = calloc(1, sizeof(*link)); + if (!link) + return ERR_PTR(-ENOMEM); + link->detach = &bpf_link__detach_fd; + + attach_type = bpf_program__get_expected_attach_type(prog); + link_fd = bpf_link_create(prog_fd, target_fd, attach_type, &opts); + if (link_fd < 0) { + link_fd = -errno; + free(link); + pr_warn("prog '%s': failed to attach to %s: %s\n", + prog->name, target_name, + libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg))); + return ERR_PTR(link_fd); + } + link->fd = link_fd; + return link; +} + +struct bpf_link * +bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd) +{ + return bpf_program__attach_fd(prog, cgroup_fd, 0, "cgroup"); +} + +struct bpf_link * +bpf_program__attach_netns(struct bpf_program *prog, int netns_fd) +{ + return bpf_program__attach_fd(prog, netns_fd, 0, "netns"); +} + +struct bpf_link *bpf_program__attach_xdp(struct bpf_program *prog, int ifindex) +{ + /* target_fd/target_ifindex use the same field in LINK_CREATE */ + return bpf_program__attach_fd(prog, ifindex, 0, "xdp"); +} + +struct bpf_link *bpf_program__attach_freplace(struct bpf_program *prog, + int target_fd, + const char *attach_func_name) +{ + int btf_id; + + if (!!target_fd != !!attach_func_name) { + pr_warn("prog '%s': supply none or both of target_fd and attach_func_name\n", + prog->name); + return ERR_PTR(-EINVAL); + } + + if (prog->type != BPF_PROG_TYPE_EXT) { + pr_warn("prog '%s': only BPF_PROG_TYPE_EXT can attach as freplace", + prog->name); + return ERR_PTR(-EINVAL); + } + + if (target_fd) { + btf_id = libbpf_find_prog_btf_id(attach_func_name, target_fd); + if (btf_id < 0) + return ERR_PTR(btf_id); + + return bpf_program__attach_fd(prog, target_fd, btf_id, "freplace"); + } else { + /* no target, so use raw_tracepoint_open for compatibility + * with old kernels + */ + return bpf_program__attach_trace(prog); + } +} + +struct bpf_link * +bpf_program__attach_iter(struct bpf_program *prog, + const struct bpf_iter_attach_opts *opts) +{ + DECLARE_LIBBPF_OPTS(bpf_link_create_opts, link_create_opts); + char errmsg[STRERR_BUFSIZE]; + struct bpf_link *link; + int prog_fd, link_fd; + __u32 target_fd = 0; + + if (!OPTS_VALID(opts, bpf_iter_attach_opts)) + return ERR_PTR(-EINVAL); + + link_create_opts.iter_info = OPTS_GET(opts, link_info, (void *)0); + link_create_opts.iter_info_len = OPTS_GET(opts, link_info_len, 0); + + prog_fd = bpf_program__fd(prog); + if (prog_fd < 0) { + pr_warn("prog '%s': can't attach before loaded\n", prog->name); + return ERR_PTR(-EINVAL); + } + + link = calloc(1, sizeof(*link)); + if (!link) + return ERR_PTR(-ENOMEM); + link->detach = &bpf_link__detach_fd; + + link_fd = bpf_link_create(prog_fd, target_fd, BPF_TRACE_ITER, + &link_create_opts); + if (link_fd < 0) { + link_fd = -errno; + free(link); + pr_warn("prog '%s': failed to attach to iterator: %s\n", + prog->name, libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg))); + return ERR_PTR(link_fd); + } + link->fd = link_fd; + return link; +} + +struct bpf_link *bpf_program__attach(struct bpf_program *prog) +{ + const struct bpf_sec_def *sec_def; + + sec_def = find_sec_def(prog->sec_name); + if (!sec_def || !sec_def->attach_fn) + return ERR_PTR(-ESRCH); + + return sec_def->attach_fn(sec_def, prog); +} + +static int bpf_link__detach_struct_ops(struct bpf_link *link) +{ + __u32 zero = 0; + + if (bpf_map_delete_elem(link->fd, &zero)) + return -errno; + + return 0; +} + +struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map) +{ + struct bpf_struct_ops *st_ops; + struct bpf_link *link; + __u32 i, zero = 0; + int err; + + if (!bpf_map__is_struct_ops(map) || map->fd == -1) + return ERR_PTR(-EINVAL); + + link = calloc(1, sizeof(*link)); + if (!link) + return ERR_PTR(-EINVAL); + + st_ops = map->st_ops; + for (i = 0; i < btf_vlen(st_ops->type); i++) { + struct bpf_program *prog = st_ops->progs[i]; + void *kern_data; + int prog_fd; + + if (!prog) + continue; + + prog_fd = bpf_program__fd(prog); + kern_data = st_ops->kern_vdata + st_ops->kern_func_off[i]; + *(unsigned long *)kern_data = prog_fd; + } + + err = bpf_map_update_elem(map->fd, &zero, st_ops->kern_vdata, 0); + if (err) { + err = -errno; + free(link); + return ERR_PTR(err); + } + + link->detach = bpf_link__detach_struct_ops; + link->fd = map->fd; + + return link; +} + +enum bpf_perf_event_ret +bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size, + void **copy_mem, size_t *copy_size, + bpf_perf_event_print_t fn, void *private_data) +{ + struct perf_event_mmap_page *header = mmap_mem; + __u64 data_head = ring_buffer_read_head(header); + __u64 data_tail = header->data_tail; + void *base = ((__u8 *)header) + page_size; + int ret = LIBBPF_PERF_EVENT_CONT; + struct perf_event_header *ehdr; + size_t ehdr_size; + + while (data_head != data_tail) { + ehdr = base + (data_tail & (mmap_size - 1)); + ehdr_size = ehdr->size; + + if (((void *)ehdr) + ehdr_size > base + mmap_size) { + void *copy_start = ehdr; + size_t len_first = base + mmap_size - copy_start; + size_t len_secnd = ehdr_size - len_first; + + if (*copy_size < ehdr_size) { + free(*copy_mem); + *copy_mem = malloc(ehdr_size); + if (!*copy_mem) { + *copy_size = 0; + ret = LIBBPF_PERF_EVENT_ERROR; + break; + } + *copy_size = ehdr_size; + } + + memcpy(*copy_mem, copy_start, len_first); + memcpy(*copy_mem + len_first, base, len_secnd); + ehdr = *copy_mem; + } + + ret = fn(ehdr, private_data); + data_tail += ehdr_size; + if (ret != LIBBPF_PERF_EVENT_CONT) + break; + } + + ring_buffer_write_tail(header, data_tail); + return ret; +} + +struct perf_buffer; + +struct perf_buffer_params { + struct perf_event_attr *attr; + /* if event_cb is specified, it takes precendence */ + perf_buffer_event_fn event_cb; + /* sample_cb and lost_cb are higher-level common-case callbacks */ + perf_buffer_sample_fn sample_cb; + perf_buffer_lost_fn lost_cb; + void *ctx; + int cpu_cnt; + int *cpus; + int *map_keys; +}; + +struct perf_cpu_buf { + struct perf_buffer *pb; + void *base; /* mmap()'ed memory */ + void *buf; /* for reconstructing segmented data */ + size_t buf_size; + int fd; + int cpu; + int map_key; +}; + +struct perf_buffer { + perf_buffer_event_fn event_cb; + perf_buffer_sample_fn sample_cb; + perf_buffer_lost_fn lost_cb; + void *ctx; /* passed into callbacks */ + + size_t page_size; + size_t mmap_size; + struct perf_cpu_buf **cpu_bufs; + struct epoll_event *events; + int cpu_cnt; /* number of allocated CPU buffers */ + int epoll_fd; /* perf event FD */ + int map_fd; /* BPF_MAP_TYPE_PERF_EVENT_ARRAY BPF map FD */ +}; + +static void perf_buffer__free_cpu_buf(struct perf_buffer *pb, + struct perf_cpu_buf *cpu_buf) +{ + if (!cpu_buf) + return; + if (cpu_buf->base && + munmap(cpu_buf->base, pb->mmap_size + pb->page_size)) + pr_warn("failed to munmap cpu_buf #%d\n", cpu_buf->cpu); + if (cpu_buf->fd >= 0) { + ioctl(cpu_buf->fd, PERF_EVENT_IOC_DISABLE, 0); + close(cpu_buf->fd); + } + free(cpu_buf->buf); + free(cpu_buf); +} + +void perf_buffer__free(struct perf_buffer *pb) +{ + int i; + + if (IS_ERR_OR_NULL(pb)) + return; + if (pb->cpu_bufs) { + for (i = 0; i < pb->cpu_cnt; i++) { + struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i]; + + if (!cpu_buf) + continue; + + bpf_map_delete_elem(pb->map_fd, &cpu_buf->map_key); + perf_buffer__free_cpu_buf(pb, cpu_buf); + } + free(pb->cpu_bufs); + } + if (pb->epoll_fd >= 0) + close(pb->epoll_fd); + free(pb->events); + free(pb); +} + +static struct perf_cpu_buf * +perf_buffer__open_cpu_buf(struct perf_buffer *pb, struct perf_event_attr *attr, + int cpu, int map_key) +{ + struct perf_cpu_buf *cpu_buf; + char msg[STRERR_BUFSIZE]; + int err; + + cpu_buf = calloc(1, sizeof(*cpu_buf)); + if (!cpu_buf) + return ERR_PTR(-ENOMEM); + + cpu_buf->pb = pb; + cpu_buf->cpu = cpu; + cpu_buf->map_key = map_key; + + cpu_buf->fd = syscall(__NR_perf_event_open, attr, -1 /* pid */, cpu, + -1, PERF_FLAG_FD_CLOEXEC); + if (cpu_buf->fd < 0) { + err = -errno; + pr_warn("failed to open perf buffer event on cpu #%d: %s\n", + cpu, libbpf_strerror_r(err, msg, sizeof(msg))); + goto error; + } + + cpu_buf->base = mmap(NULL, pb->mmap_size + pb->page_size, + PROT_READ | PROT_WRITE, MAP_SHARED, + cpu_buf->fd, 0); + if (cpu_buf->base == MAP_FAILED) { + cpu_buf->base = NULL; + err = -errno; + pr_warn("failed to mmap perf buffer on cpu #%d: %s\n", + cpu, libbpf_strerror_r(err, msg, sizeof(msg))); + goto error; + } + + if (ioctl(cpu_buf->fd, PERF_EVENT_IOC_ENABLE, 0) < 0) { + err = -errno; + pr_warn("failed to enable perf buffer event on cpu #%d: %s\n", + cpu, libbpf_strerror_r(err, msg, sizeof(msg))); + goto error; + } + + return cpu_buf; + +error: + perf_buffer__free_cpu_buf(pb, cpu_buf); + return (struct perf_cpu_buf *)ERR_PTR(err); +} + +static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt, + struct perf_buffer_params *p); + +struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt, + const struct perf_buffer_opts *opts) +{ + struct perf_buffer_params p = {}; + struct perf_event_attr attr = { 0, }; + + attr.config = PERF_COUNT_SW_BPF_OUTPUT; + attr.type = PERF_TYPE_SOFTWARE; + attr.sample_type = PERF_SAMPLE_RAW; + attr.sample_period = 1; + attr.wakeup_events = 1; + + p.attr = &attr; + p.sample_cb = opts ? opts->sample_cb : NULL; + p.lost_cb = opts ? opts->lost_cb : NULL; + p.ctx = opts ? opts->ctx : NULL; + + return __perf_buffer__new(map_fd, page_cnt, &p); +} + +struct perf_buffer * +perf_buffer__new_raw(int map_fd, size_t page_cnt, + const struct perf_buffer_raw_opts *opts) +{ + struct perf_buffer_params p = {}; + + p.attr = opts->attr; + p.event_cb = opts->event_cb; + p.ctx = opts->ctx; + p.cpu_cnt = opts->cpu_cnt; + p.cpus = opts->cpus; + p.map_keys = opts->map_keys; + + return __perf_buffer__new(map_fd, page_cnt, &p); +} + +static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt, + struct perf_buffer_params *p) +{ + const char *online_cpus_file = "/sys/devices/system/cpu/online"; + struct bpf_map_info map; + char msg[STRERR_BUFSIZE]; + struct perf_buffer *pb; + bool *online = NULL; + __u32 map_info_len; + int err, i, j, n; + + if (page_cnt & (page_cnt - 1)) { + pr_warn("page count should be power of two, but is %zu\n", + page_cnt); + return ERR_PTR(-EINVAL); + } + + /* best-effort sanity checks */ + memset(&map, 0, sizeof(map)); + map_info_len = sizeof(map); + err = bpf_obj_get_info_by_fd(map_fd, &map, &map_info_len); + if (err) { + err = -errno; + /* if BPF_OBJ_GET_INFO_BY_FD is supported, will return + * -EBADFD, -EFAULT, or -E2BIG on real error + */ + if (err != -EINVAL) { + pr_warn("failed to get map info for map FD %d: %s\n", + map_fd, libbpf_strerror_r(err, msg, sizeof(msg))); + return ERR_PTR(err); + } + pr_debug("failed to get map info for FD %d; API not supported? Ignoring...\n", + map_fd); + } else { + if (map.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) { + pr_warn("map '%s' should be BPF_MAP_TYPE_PERF_EVENT_ARRAY\n", + map.name); + return ERR_PTR(-EINVAL); + } + } + + pb = calloc(1, sizeof(*pb)); + if (!pb) + return ERR_PTR(-ENOMEM); + + pb->event_cb = p->event_cb; + pb->sample_cb = p->sample_cb; + pb->lost_cb = p->lost_cb; + pb->ctx = p->ctx; + + pb->page_size = getpagesize(); + pb->mmap_size = pb->page_size * page_cnt; + pb->map_fd = map_fd; + + pb->epoll_fd = epoll_create1(EPOLL_CLOEXEC); + if (pb->epoll_fd < 0) { + err = -errno; + pr_warn("failed to create epoll instance: %s\n", + libbpf_strerror_r(err, msg, sizeof(msg))); + goto error; + } + + if (p->cpu_cnt > 0) { + pb->cpu_cnt = p->cpu_cnt; + } else { + pb->cpu_cnt = libbpf_num_possible_cpus(); + if (pb->cpu_cnt < 0) { + err = pb->cpu_cnt; + goto error; + } + if (map.max_entries && map.max_entries < pb->cpu_cnt) + pb->cpu_cnt = map.max_entries; + } + + pb->events = calloc(pb->cpu_cnt, sizeof(*pb->events)); + if (!pb->events) { + err = -ENOMEM; + pr_warn("failed to allocate events: out of memory\n"); + goto error; + } + pb->cpu_bufs = calloc(pb->cpu_cnt, sizeof(*pb->cpu_bufs)); + if (!pb->cpu_bufs) { + err = -ENOMEM; + pr_warn("failed to allocate buffers: out of memory\n"); + goto error; + } + + err = parse_cpu_mask_file(online_cpus_file, &online, &n); + if (err) { + pr_warn("failed to get online CPU mask: %d\n", err); + goto error; + } + + for (i = 0, j = 0; i < pb->cpu_cnt; i++) { + struct perf_cpu_buf *cpu_buf; + int cpu, map_key; + + cpu = p->cpu_cnt > 0 ? p->cpus[i] : i; + map_key = p->cpu_cnt > 0 ? p->map_keys[i] : i; + + /* in case user didn't explicitly requested particular CPUs to + * be attached to, skip offline/not present CPUs + */ + if (p->cpu_cnt <= 0 && (cpu >= n || !online[cpu])) + continue; + + cpu_buf = perf_buffer__open_cpu_buf(pb, p->attr, cpu, map_key); + if (IS_ERR(cpu_buf)) { + err = PTR_ERR(cpu_buf); + goto error; + } + + pb->cpu_bufs[j] = cpu_buf; + + err = bpf_map_update_elem(pb->map_fd, &map_key, + &cpu_buf->fd, 0); + if (err) { + err = -errno; + pr_warn("failed to set cpu #%d, key %d -> perf FD %d: %s\n", + cpu, map_key, cpu_buf->fd, + libbpf_strerror_r(err, msg, sizeof(msg))); + goto error; + } + + pb->events[j].events = EPOLLIN; + pb->events[j].data.ptr = cpu_buf; + if (epoll_ctl(pb->epoll_fd, EPOLL_CTL_ADD, cpu_buf->fd, + &pb->events[j]) < 0) { + err = -errno; + pr_warn("failed to epoll_ctl cpu #%d perf FD %d: %s\n", + cpu, cpu_buf->fd, + libbpf_strerror_r(err, msg, sizeof(msg))); + goto error; + } + j++; + } + pb->cpu_cnt = j; + free(online); + + return pb; + +error: + free(online); + if (pb) + perf_buffer__free(pb); + return ERR_PTR(err); +} + +struct perf_sample_raw { + struct perf_event_header header; + uint32_t size; + char data[]; +}; + +struct perf_sample_lost { + struct perf_event_header header; + uint64_t id; + uint64_t lost; + uint64_t sample_id; +}; + +static enum bpf_perf_event_ret +perf_buffer__process_record(struct perf_event_header *e, void *ctx) +{ + struct perf_cpu_buf *cpu_buf = ctx; + struct perf_buffer *pb = cpu_buf->pb; + void *data = e; + + /* user wants full control over parsing perf event */ + if (pb->event_cb) + return pb->event_cb(pb->ctx, cpu_buf->cpu, e); + + switch (e->type) { + case PERF_RECORD_SAMPLE: { + struct perf_sample_raw *s = data; + + if (pb->sample_cb) + pb->sample_cb(pb->ctx, cpu_buf->cpu, s->data, s->size); + break; + } + case PERF_RECORD_LOST: { + struct perf_sample_lost *s = data; + + if (pb->lost_cb) + pb->lost_cb(pb->ctx, cpu_buf->cpu, s->lost); + break; + } + default: + pr_warn("unknown perf sample type %d\n", e->type); + return LIBBPF_PERF_EVENT_ERROR; + } + return LIBBPF_PERF_EVENT_CONT; +} + +static int perf_buffer__process_records(struct perf_buffer *pb, + struct perf_cpu_buf *cpu_buf) +{ + enum bpf_perf_event_ret ret; + + ret = bpf_perf_event_read_simple(cpu_buf->base, pb->mmap_size, + pb->page_size, &cpu_buf->buf, + &cpu_buf->buf_size, + perf_buffer__process_record, cpu_buf); + if (ret != LIBBPF_PERF_EVENT_CONT) + return ret; + return 0; +} + +int perf_buffer__epoll_fd(const struct perf_buffer *pb) +{ + return pb->epoll_fd; +} + +int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms) +{ + int i, cnt, err; + + cnt = epoll_wait(pb->epoll_fd, pb->events, pb->cpu_cnt, timeout_ms); + for (i = 0; i < cnt; i++) { + struct perf_cpu_buf *cpu_buf = pb->events[i].data.ptr; + + err = perf_buffer__process_records(pb, cpu_buf); + if (err) { + pr_warn("error while processing records: %d\n", err); + return err; + } + } + return cnt < 0 ? -errno : cnt; +} + +/* Return number of PERF_EVENT_ARRAY map slots set up by this perf_buffer + * manager. + */ +size_t perf_buffer__buffer_cnt(const struct perf_buffer *pb) +{ + return pb->cpu_cnt; +} + +/* + * Return perf_event FD of a ring buffer in *buf_idx* slot of + * PERF_EVENT_ARRAY BPF map. This FD can be polled for new data using + * select()/poll()/epoll() Linux syscalls. + */ +int perf_buffer__buffer_fd(const struct perf_buffer *pb, size_t buf_idx) +{ + struct perf_cpu_buf *cpu_buf; + + if (buf_idx >= pb->cpu_cnt) + return -EINVAL; + + cpu_buf = pb->cpu_bufs[buf_idx]; + if (!cpu_buf) + return -ENOENT; + + return cpu_buf->fd; +} + +/* + * Consume data from perf ring buffer corresponding to slot *buf_idx* in + * PERF_EVENT_ARRAY BPF map without waiting/polling. If there is no data to + * consume, do nothing and return success. + * Returns: + * - 0 on success; + * - <0 on failure. + */ +int perf_buffer__consume_buffer(struct perf_buffer *pb, size_t buf_idx) +{ + struct perf_cpu_buf *cpu_buf; + + if (buf_idx >= pb->cpu_cnt) + return -EINVAL; + + cpu_buf = pb->cpu_bufs[buf_idx]; + if (!cpu_buf) + return -ENOENT; + + return perf_buffer__process_records(pb, cpu_buf); +} + +int perf_buffer__consume(struct perf_buffer *pb) +{ + int i, err; + + for (i = 0; i < pb->cpu_cnt; i++) { + struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i]; + + if (!cpu_buf) + continue; + + err = perf_buffer__process_records(pb, cpu_buf); + if (err) { + pr_warn("perf_buffer: failed to process records in buffer #%d: %d\n", i, err); + return err; + } + } + return 0; +} + +struct bpf_prog_info_array_desc { + int array_offset; /* e.g. offset of jited_prog_insns */ + int count_offset; /* e.g. offset of jited_prog_len */ + int size_offset; /* > 0: offset of rec size, + * < 0: fix size of -size_offset + */ +}; + +static struct bpf_prog_info_array_desc bpf_prog_info_array_desc[] = { + [BPF_PROG_INFO_JITED_INSNS] = { + offsetof(struct bpf_prog_info, jited_prog_insns), + offsetof(struct bpf_prog_info, jited_prog_len), + -1, + }, + [BPF_PROG_INFO_XLATED_INSNS] = { + offsetof(struct bpf_prog_info, xlated_prog_insns), + offsetof(struct bpf_prog_info, xlated_prog_len), + -1, + }, + [BPF_PROG_INFO_MAP_IDS] = { + offsetof(struct bpf_prog_info, map_ids), + offsetof(struct bpf_prog_info, nr_map_ids), + -(int)sizeof(__u32), + }, + [BPF_PROG_INFO_JITED_KSYMS] = { + offsetof(struct bpf_prog_info, jited_ksyms), + offsetof(struct bpf_prog_info, nr_jited_ksyms), + -(int)sizeof(__u64), + }, + [BPF_PROG_INFO_JITED_FUNC_LENS] = { + offsetof(struct bpf_prog_info, jited_func_lens), + offsetof(struct bpf_prog_info, nr_jited_func_lens), + -(int)sizeof(__u32), + }, + [BPF_PROG_INFO_FUNC_INFO] = { + offsetof(struct bpf_prog_info, func_info), + offsetof(struct bpf_prog_info, nr_func_info), + offsetof(struct bpf_prog_info, func_info_rec_size), + }, + [BPF_PROG_INFO_LINE_INFO] = { + offsetof(struct bpf_prog_info, line_info), + offsetof(struct bpf_prog_info, nr_line_info), + offsetof(struct bpf_prog_info, line_info_rec_size), + }, + [BPF_PROG_INFO_JITED_LINE_INFO] = { + offsetof(struct bpf_prog_info, jited_line_info), + offsetof(struct bpf_prog_info, nr_jited_line_info), + offsetof(struct bpf_prog_info, jited_line_info_rec_size), + }, + [BPF_PROG_INFO_PROG_TAGS] = { + offsetof(struct bpf_prog_info, prog_tags), + offsetof(struct bpf_prog_info, nr_prog_tags), + -(int)sizeof(__u8) * BPF_TAG_SIZE, + }, + +}; + +static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info, + int offset) +{ + __u32 *array = (__u32 *)info; + + if (offset >= 0) + return array[offset / sizeof(__u32)]; + return -(int)offset; +} + +static __u64 bpf_prog_info_read_offset_u64(struct bpf_prog_info *info, + int offset) +{ + __u64 *array = (__u64 *)info; + + if (offset >= 0) + return array[offset / sizeof(__u64)]; + return -(int)offset; +} + +static void bpf_prog_info_set_offset_u32(struct bpf_prog_info *info, int offset, + __u32 val) +{ + __u32 *array = (__u32 *)info; + + if (offset >= 0) + array[offset / sizeof(__u32)] = val; +} + +static void bpf_prog_info_set_offset_u64(struct bpf_prog_info *info, int offset, + __u64 val) +{ + __u64 *array = (__u64 *)info; + + if (offset >= 0) + array[offset / sizeof(__u64)] = val; +} + +struct bpf_prog_info_linear * +bpf_program__get_prog_info_linear(int fd, __u64 arrays) +{ + struct bpf_prog_info_linear *info_linear; + struct bpf_prog_info info = {}; + __u32 info_len = sizeof(info); + __u32 data_len = 0; + int i, err; + void *ptr; + + if (arrays >> BPF_PROG_INFO_LAST_ARRAY) + return ERR_PTR(-EINVAL); + + /* step 1: get array dimensions */ + err = bpf_obj_get_info_by_fd(fd, &info, &info_len); + if (err) { + pr_debug("can't get prog info: %s", strerror(errno)); + return ERR_PTR(-EFAULT); + } + + /* step 2: calculate total size of all arrays */ + for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { + bool include_array = (arrays & (1UL << i)) > 0; + struct bpf_prog_info_array_desc *desc; + __u32 count, size; + + desc = bpf_prog_info_array_desc + i; + + /* kernel is too old to support this field */ + if (info_len < desc->array_offset + sizeof(__u32) || + info_len < desc->count_offset + sizeof(__u32) || + (desc->size_offset > 0 && info_len < desc->size_offset)) + include_array = false; + + if (!include_array) { + arrays &= ~(1UL << i); /* clear the bit */ + continue; + } + + count = bpf_prog_info_read_offset_u32(&info, desc->count_offset); + size = bpf_prog_info_read_offset_u32(&info, desc->size_offset); + + data_len += count * size; + } + + /* step 3: allocate continuous memory */ + data_len = roundup(data_len, sizeof(__u64)); + info_linear = malloc(sizeof(struct bpf_prog_info_linear) + data_len); + if (!info_linear) + return ERR_PTR(-ENOMEM); + + /* step 4: fill data to info_linear->info */ + info_linear->arrays = arrays; + memset(&info_linear->info, 0, sizeof(info)); + ptr = info_linear->data; + + for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { + struct bpf_prog_info_array_desc *desc; + __u32 count, size; + + if ((arrays & (1UL << i)) == 0) + continue; + + desc = bpf_prog_info_array_desc + i; + count = bpf_prog_info_read_offset_u32(&info, desc->count_offset); + size = bpf_prog_info_read_offset_u32(&info, desc->size_offset); + bpf_prog_info_set_offset_u32(&info_linear->info, + desc->count_offset, count); + bpf_prog_info_set_offset_u32(&info_linear->info, + desc->size_offset, size); + bpf_prog_info_set_offset_u64(&info_linear->info, + desc->array_offset, + ptr_to_u64(ptr)); + ptr += count * size; + } + + /* step 5: call syscall again to get required arrays */ + err = bpf_obj_get_info_by_fd(fd, &info_linear->info, &info_len); + if (err) { + pr_debug("can't get prog info: %s", strerror(errno)); + free(info_linear); + return ERR_PTR(-EFAULT); + } + + /* step 6: verify the data */ + for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { + struct bpf_prog_info_array_desc *desc; + __u32 v1, v2; + + if ((arrays & (1UL << i)) == 0) + continue; + + desc = bpf_prog_info_array_desc + i; + v1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset); + v2 = bpf_prog_info_read_offset_u32(&info_linear->info, + desc->count_offset); + if (v1 != v2) + pr_warn("%s: mismatch in element count\n", __func__); + + v1 = bpf_prog_info_read_offset_u32(&info, desc->size_offset); + v2 = bpf_prog_info_read_offset_u32(&info_linear->info, + desc->size_offset); + if (v1 != v2) + pr_warn("%s: mismatch in rec size\n", __func__); + } + + /* step 7: update info_len and data_len */ + info_linear->info_len = sizeof(struct bpf_prog_info); + info_linear->data_len = data_len; + + return info_linear; +} + +void bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear) +{ + int i; + + for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { + struct bpf_prog_info_array_desc *desc; + __u64 addr, offs; + + if ((info_linear->arrays & (1UL << i)) == 0) + continue; + + desc = bpf_prog_info_array_desc + i; + addr = bpf_prog_info_read_offset_u64(&info_linear->info, + desc->array_offset); + offs = addr - ptr_to_u64(info_linear->data); + bpf_prog_info_set_offset_u64(&info_linear->info, + desc->array_offset, offs); + } +} + +void bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear) +{ + int i; + + for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { + struct bpf_prog_info_array_desc *desc; + __u64 addr, offs; + + if ((info_linear->arrays & (1UL << i)) == 0) + continue; + + desc = bpf_prog_info_array_desc + i; + offs = bpf_prog_info_read_offset_u64(&info_linear->info, + desc->array_offset); + addr = offs + ptr_to_u64(info_linear->data); + bpf_prog_info_set_offset_u64(&info_linear->info, + desc->array_offset, addr); + } +} + +int bpf_program__set_attach_target(struct bpf_program *prog, + int attach_prog_fd, + const char *attach_func_name) +{ + int btf_id; + + if (!prog || attach_prog_fd < 0 || !attach_func_name) + return -EINVAL; + + if (attach_prog_fd) + btf_id = libbpf_find_prog_btf_id(attach_func_name, + attach_prog_fd); + else + btf_id = libbpf_find_vmlinux_btf_id(attach_func_name, + prog->expected_attach_type); + + if (btf_id < 0) + return btf_id; + + prog->attach_btf_id = btf_id; + prog->attach_prog_fd = attach_prog_fd; + return 0; +} + +int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz) +{ + int err = 0, n, len, start, end = -1; + bool *tmp; + + *mask = NULL; + *mask_sz = 0; + + /* Each sub string separated by ',' has format \d+-\d+ or \d+ */ + while (*s) { + if (*s == ',' || *s == '\n') { + s++; + continue; + } + n = sscanf(s, "%d%n-%d%n", &start, &len, &end, &len); + if (n <= 0 || n > 2) { + pr_warn("Failed to get CPU range %s: %d\n", s, n); + err = -EINVAL; + goto cleanup; + } else if (n == 1) { + end = start; + } + if (start < 0 || start > end) { + pr_warn("Invalid CPU range [%d,%d] in %s\n", + start, end, s); + err = -EINVAL; + goto cleanup; + } + tmp = realloc(*mask, end + 1); + if (!tmp) { + err = -ENOMEM; + goto cleanup; + } + *mask = tmp; + memset(tmp + *mask_sz, 0, start - *mask_sz); + memset(tmp + start, 1, end - start + 1); + *mask_sz = end + 1; + s += len; + } + if (!*mask_sz) { + pr_warn("Empty CPU range\n"); + return -EINVAL; + } + return 0; +cleanup: + free(*mask); + *mask = NULL; + return err; +} + +int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz) +{ + int fd, err = 0, len; + char buf[128]; + + fd = open(fcpu, O_RDONLY); + if (fd < 0) { + err = -errno; + pr_warn("Failed to open cpu mask file %s: %d\n", fcpu, err); + return err; + } + len = read(fd, buf, sizeof(buf)); + close(fd); + if (len <= 0) { + err = len ? -errno : -EINVAL; + pr_warn("Failed to read cpu mask from %s: %d\n", fcpu, err); + return err; + } + if (len >= sizeof(buf)) { + pr_warn("CPU mask is too big in file %s\n", fcpu); + return -E2BIG; + } + buf[len] = '\0'; + + return parse_cpu_mask_str(buf, mask, mask_sz); +} + +int libbpf_num_possible_cpus(void) +{ + static const char *fcpu = "/sys/devices/system/cpu/possible"; + static int cpus; + int err, n, i, tmp_cpus; + bool *mask; + + tmp_cpus = READ_ONCE(cpus); + if (tmp_cpus > 0) + return tmp_cpus; + + err = parse_cpu_mask_file(fcpu, &mask, &n); + if (err) + return err; + + tmp_cpus = 0; + for (i = 0; i < n; i++) { + if (mask[i]) + tmp_cpus++; + } + free(mask); + + WRITE_ONCE(cpus, tmp_cpus); + return tmp_cpus; +} + +int bpf_object__open_skeleton(struct bpf_object_skeleton *s, + const struct bpf_object_open_opts *opts) +{ + DECLARE_LIBBPF_OPTS(bpf_object_open_opts, skel_opts, + .object_name = s->name, + ); + struct bpf_object *obj; + int i; + + /* Attempt to preserve opts->object_name, unless overriden by user + * explicitly. Overwriting object name for skeletons is discouraged, + * as it breaks global data maps, because they contain object name + * prefix as their own map name prefix. When skeleton is generated, + * bpftool is making an assumption that this name will stay the same. + */ + if (opts) { + memcpy(&skel_opts, opts, sizeof(*opts)); + if (!opts->object_name) + skel_opts.object_name = s->name; + } + + obj = bpf_object__open_mem(s->data, s->data_sz, &skel_opts); + if (IS_ERR(obj)) { + pr_warn("failed to initialize skeleton BPF object '%s': %ld\n", + s->name, PTR_ERR(obj)); + return PTR_ERR(obj); + } + + *s->obj = obj; + + for (i = 0; i < s->map_cnt; i++) { + struct bpf_map **map = s->maps[i].map; + const char *name = s->maps[i].name; + void **mmaped = s->maps[i].mmaped; + + *map = bpf_object__find_map_by_name(obj, name); + if (!*map) { + pr_warn("failed to find skeleton map '%s'\n", name); + return -ESRCH; + } + + /* externs shouldn't be pre-setup from user code */ + if (mmaped && (*map)->libbpf_type != LIBBPF_MAP_KCONFIG) + *mmaped = (*map)->mmaped; + } + + for (i = 0; i < s->prog_cnt; i++) { + struct bpf_program **prog = s->progs[i].prog; + const char *name = s->progs[i].name; + + *prog = bpf_object__find_program_by_name(obj, name); + if (!*prog) { + pr_warn("failed to find skeleton program '%s'\n", name); + return -ESRCH; + } + } + + return 0; +} + +int bpf_object__load_skeleton(struct bpf_object_skeleton *s) +{ + int i, err; + + err = bpf_object__load(*s->obj); + if (err) { + pr_warn("failed to load BPF skeleton '%s': %d\n", s->name, err); + return err; + } + + for (i = 0; i < s->map_cnt; i++) { + struct bpf_map *map = *s->maps[i].map; + size_t mmap_sz = bpf_map_mmap_sz(map); + int prot, map_fd = bpf_map__fd(map); + void **mmaped = s->maps[i].mmaped; + + if (!mmaped) + continue; + + if (!(map->def.map_flags & BPF_F_MMAPABLE)) { + *mmaped = NULL; + continue; + } + + if (map->def.map_flags & BPF_F_RDONLY_PROG) + prot = PROT_READ; + else + prot = PROT_READ | PROT_WRITE; + + /* Remap anonymous mmap()-ed "map initialization image" as + * a BPF map-backed mmap()-ed memory, but preserving the same + * memory address. This will cause kernel to change process' + * page table to point to a different piece of kernel memory, + * but from userspace point of view memory address (and its + * contents, being identical at this point) will stay the + * same. This mapping will be released by bpf_object__close() + * as per normal clean up procedure, so we don't need to worry + * about it from skeleton's clean up perspective. + */ + *mmaped = mmap(map->mmaped, mmap_sz, prot, + MAP_SHARED | MAP_FIXED, map_fd, 0); + if (*mmaped == MAP_FAILED) { + err = -errno; + *mmaped = NULL; + pr_warn("failed to re-mmap() map '%s': %d\n", + bpf_map__name(map), err); + return err; + } + } + + return 0; +} + +int bpf_object__attach_skeleton(struct bpf_object_skeleton *s) +{ + int i; + + for (i = 0; i < s->prog_cnt; i++) { + struct bpf_program *prog = *s->progs[i].prog; + struct bpf_link **link = s->progs[i].link; + const struct bpf_sec_def *sec_def; + + if (!prog->load) + continue; + + sec_def = find_sec_def(prog->sec_name); + if (!sec_def || !sec_def->attach_fn) + continue; + + *link = sec_def->attach_fn(sec_def, prog); + if (IS_ERR(*link)) { + pr_warn("failed to auto-attach program '%s': %ld\n", + bpf_program__name(prog), PTR_ERR(*link)); + return PTR_ERR(*link); + } + } + + return 0; +} + +void bpf_object__detach_skeleton(struct bpf_object_skeleton *s) +{ + int i; + + for (i = 0; i < s->prog_cnt; i++) { + struct bpf_link **link = s->progs[i].link; + + bpf_link__destroy(*link); + *link = NULL; + } +} + +void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s) +{ + if (!s) + return; + + if (s->progs) + bpf_object__detach_skeleton(s); + if (s->obj) + bpf_object__close(*s->obj); + free(s->maps); + free(s->progs); + free(s); +} diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h new file mode 100644 index 000000000..57d10b779 --- /dev/null +++ b/tools/lib/bpf/libbpf.h @@ -0,0 +1,766 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ + +/* + * Common eBPF ELF object loading operations. + * + * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org> + * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com> + * Copyright (C) 2015 Huawei Inc. + */ +#ifndef __LIBBPF_LIBBPF_H +#define __LIBBPF_LIBBPF_H + +#include <stdarg.h> +#include <stdio.h> +#include <stdint.h> +#include <stdbool.h> +#include <sys/types.h> // for size_t +#include <linux/bpf.h> + +#include "libbpf_common.h" + +#ifdef __cplusplus +extern "C" { +#endif + +enum libbpf_errno { + __LIBBPF_ERRNO__START = 4000, + + /* Something wrong in libelf */ + LIBBPF_ERRNO__LIBELF = __LIBBPF_ERRNO__START, + LIBBPF_ERRNO__FORMAT, /* BPF object format invalid */ + LIBBPF_ERRNO__KVERSION, /* Incorrect or no 'version' section */ + LIBBPF_ERRNO__ENDIAN, /* Endian mismatch */ + LIBBPF_ERRNO__INTERNAL, /* Internal error in libbpf */ + LIBBPF_ERRNO__RELOC, /* Relocation failed */ + LIBBPF_ERRNO__LOAD, /* Load program failure for unknown reason */ + LIBBPF_ERRNO__VERIFY, /* Kernel verifier blocks program loading */ + LIBBPF_ERRNO__PROG2BIG, /* Program too big */ + LIBBPF_ERRNO__KVER, /* Incorrect kernel version */ + LIBBPF_ERRNO__PROGTYPE, /* Kernel doesn't support this program type */ + LIBBPF_ERRNO__WRNGPID, /* Wrong pid in netlink message */ + LIBBPF_ERRNO__INVSEQ, /* Invalid netlink sequence */ + LIBBPF_ERRNO__NLPARSE, /* netlink parsing error */ + __LIBBPF_ERRNO__END, +}; + +LIBBPF_API int libbpf_strerror(int err, char *buf, size_t size); + +enum libbpf_print_level { + LIBBPF_WARN, + LIBBPF_INFO, + LIBBPF_DEBUG, +}; + +typedef int (*libbpf_print_fn_t)(enum libbpf_print_level level, + const char *, va_list ap); + +LIBBPF_API libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn); + +/* Hide internal to user */ +struct bpf_object; + +struct bpf_object_open_attr { + const char *file; + enum bpf_prog_type prog_type; +}; + +struct bpf_object_open_opts { + /* size of this struct, for forward/backward compatiblity */ + size_t sz; + /* object name override, if provided: + * - for object open from file, this will override setting object + * name from file path's base name; + * - for object open from memory buffer, this will specify an object + * name and will override default "<addr>-<buf-size>" name; + */ + const char *object_name; + /* parse map definitions non-strictly, allowing extra attributes/data */ + bool relaxed_maps; + /* DEPRECATED: handle CO-RE relocations non-strictly, allowing failures. + * Value is ignored. Relocations always are processed non-strictly. + * Non-relocatable instructions are replaced with invalid ones to + * prevent accidental errors. + * */ + bool relaxed_core_relocs; + /* maps that set the 'pinning' attribute in their definition will have + * their pin_path attribute set to a file in this directory, and be + * auto-pinned to that path on load; defaults to "/sys/fs/bpf". + */ + const char *pin_root_path; + __u32 attach_prog_fd; + /* Additional kernel config content that augments and overrides + * system Kconfig for CONFIG_xxx externs. + */ + const char *kconfig; +}; +#define bpf_object_open_opts__last_field kconfig + +LIBBPF_API struct bpf_object *bpf_object__open(const char *path); +LIBBPF_API struct bpf_object * +bpf_object__open_file(const char *path, const struct bpf_object_open_opts *opts); +LIBBPF_API struct bpf_object * +bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz, + const struct bpf_object_open_opts *opts); + +/* deprecated bpf_object__open variants */ +LIBBPF_API struct bpf_object * +bpf_object__open_buffer(const void *obj_buf, size_t obj_buf_sz, + const char *name); +LIBBPF_API struct bpf_object * +bpf_object__open_xattr(struct bpf_object_open_attr *attr); + +enum libbpf_pin_type { + LIBBPF_PIN_NONE, + /* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */ + LIBBPF_PIN_BY_NAME, +}; + +/* pin_maps and unpin_maps can both be called with a NULL path, in which case + * they will use the pin_path attribute of each map (and ignore all maps that + * don't have a pin_path set). + */ +LIBBPF_API int bpf_object__pin_maps(struct bpf_object *obj, const char *path); +LIBBPF_API int bpf_object__unpin_maps(struct bpf_object *obj, + const char *path); +LIBBPF_API int bpf_object__pin_programs(struct bpf_object *obj, + const char *path); +LIBBPF_API int bpf_object__unpin_programs(struct bpf_object *obj, + const char *path); +LIBBPF_API int bpf_object__pin(struct bpf_object *object, const char *path); +LIBBPF_API void bpf_object__close(struct bpf_object *object); + +struct bpf_object_load_attr { + struct bpf_object *obj; + int log_level; + const char *target_btf_path; +}; + +/* Load/unload object into/from kernel */ +LIBBPF_API int bpf_object__load(struct bpf_object *obj); +LIBBPF_API int bpf_object__load_xattr(struct bpf_object_load_attr *attr); +LIBBPF_API int bpf_object__unload(struct bpf_object *obj); + +LIBBPF_API const char *bpf_object__name(const struct bpf_object *obj); +LIBBPF_API unsigned int bpf_object__kversion(const struct bpf_object *obj); + +struct btf; +LIBBPF_API struct btf *bpf_object__btf(const struct bpf_object *obj); +LIBBPF_API int bpf_object__btf_fd(const struct bpf_object *obj); + +LIBBPF_API struct bpf_program * +bpf_object__find_program_by_title(const struct bpf_object *obj, + const char *title); +LIBBPF_API struct bpf_program * +bpf_object__find_program_by_name(const struct bpf_object *obj, + const char *name); + +LIBBPF_API struct bpf_object *bpf_object__next(struct bpf_object *prev); +#define bpf_object__for_each_safe(pos, tmp) \ + for ((pos) = bpf_object__next(NULL), \ + (tmp) = bpf_object__next(pos); \ + (pos) != NULL; \ + (pos) = (tmp), (tmp) = bpf_object__next(tmp)) + +typedef void (*bpf_object_clear_priv_t)(struct bpf_object *, void *); +LIBBPF_API int bpf_object__set_priv(struct bpf_object *obj, void *priv, + bpf_object_clear_priv_t clear_priv); +LIBBPF_API void *bpf_object__priv(const struct bpf_object *prog); + +LIBBPF_API int +libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type, + enum bpf_attach_type *expected_attach_type); +LIBBPF_API int libbpf_attach_type_by_name(const char *name, + enum bpf_attach_type *attach_type); +LIBBPF_API int libbpf_find_vmlinux_btf_id(const char *name, + enum bpf_attach_type attach_type); + +/* Accessors of bpf_program */ +struct bpf_program; +LIBBPF_API struct bpf_program *bpf_program__next(struct bpf_program *prog, + const struct bpf_object *obj); + +#define bpf_object__for_each_program(pos, obj) \ + for ((pos) = bpf_program__next(NULL, (obj)); \ + (pos) != NULL; \ + (pos) = bpf_program__next((pos), (obj))) + +LIBBPF_API struct bpf_program *bpf_program__prev(struct bpf_program *prog, + const struct bpf_object *obj); + +typedef void (*bpf_program_clear_priv_t)(struct bpf_program *, void *); + +LIBBPF_API int bpf_program__set_priv(struct bpf_program *prog, void *priv, + bpf_program_clear_priv_t clear_priv); + +LIBBPF_API void *bpf_program__priv(const struct bpf_program *prog); +LIBBPF_API void bpf_program__set_ifindex(struct bpf_program *prog, + __u32 ifindex); + +LIBBPF_API const char *bpf_program__name(const struct bpf_program *prog); +LIBBPF_API const char *bpf_program__section_name(const struct bpf_program *prog); +LIBBPF_API LIBBPF_DEPRECATED("BPF program title is confusing term; please use bpf_program__section_name() instead") +const char *bpf_program__title(const struct bpf_program *prog, bool needs_copy); +LIBBPF_API bool bpf_program__autoload(const struct bpf_program *prog); +LIBBPF_API int bpf_program__set_autoload(struct bpf_program *prog, bool autoload); + +/* returns program size in bytes */ +LIBBPF_API size_t bpf_program__size(const struct bpf_program *prog); + +LIBBPF_API int bpf_program__load(struct bpf_program *prog, char *license, + __u32 kern_version); +LIBBPF_API int bpf_program__fd(const struct bpf_program *prog); +LIBBPF_API int bpf_program__pin_instance(struct bpf_program *prog, + const char *path, + int instance); +LIBBPF_API int bpf_program__unpin_instance(struct bpf_program *prog, + const char *path, + int instance); +LIBBPF_API int bpf_program__pin(struct bpf_program *prog, const char *path); +LIBBPF_API int bpf_program__unpin(struct bpf_program *prog, const char *path); +LIBBPF_API void bpf_program__unload(struct bpf_program *prog); + +struct bpf_link; + +LIBBPF_API struct bpf_link *bpf_link__open(const char *path); +LIBBPF_API int bpf_link__fd(const struct bpf_link *link); +LIBBPF_API const char *bpf_link__pin_path(const struct bpf_link *link); +LIBBPF_API int bpf_link__pin(struct bpf_link *link, const char *path); +LIBBPF_API int bpf_link__unpin(struct bpf_link *link); +LIBBPF_API int bpf_link__update_program(struct bpf_link *link, + struct bpf_program *prog); +LIBBPF_API void bpf_link__disconnect(struct bpf_link *link); +LIBBPF_API int bpf_link__detach(struct bpf_link *link); +LIBBPF_API int bpf_link__destroy(struct bpf_link *link); + +LIBBPF_API struct bpf_link * +bpf_program__attach(struct bpf_program *prog); +LIBBPF_API struct bpf_link * +bpf_program__attach_perf_event(struct bpf_program *prog, int pfd); +LIBBPF_API struct bpf_link * +bpf_program__attach_kprobe(struct bpf_program *prog, bool retprobe, + const char *func_name); +LIBBPF_API struct bpf_link * +bpf_program__attach_uprobe(struct bpf_program *prog, bool retprobe, + pid_t pid, const char *binary_path, + size_t func_offset); +LIBBPF_API struct bpf_link * +bpf_program__attach_tracepoint(struct bpf_program *prog, + const char *tp_category, + const char *tp_name); +LIBBPF_API struct bpf_link * +bpf_program__attach_raw_tracepoint(struct bpf_program *prog, + const char *tp_name); +LIBBPF_API struct bpf_link * +bpf_program__attach_trace(struct bpf_program *prog); +LIBBPF_API struct bpf_link * +bpf_program__attach_lsm(struct bpf_program *prog); +LIBBPF_API struct bpf_link * +bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd); +LIBBPF_API struct bpf_link * +bpf_program__attach_netns(struct bpf_program *prog, int netns_fd); +LIBBPF_API struct bpf_link * +bpf_program__attach_xdp(struct bpf_program *prog, int ifindex); +LIBBPF_API struct bpf_link * +bpf_program__attach_freplace(struct bpf_program *prog, + int target_fd, const char *attach_func_name); + +struct bpf_map; + +LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map); + +struct bpf_iter_attach_opts { + size_t sz; /* size of this struct for forward/backward compatibility */ + union bpf_iter_link_info *link_info; + __u32 link_info_len; +}; +#define bpf_iter_attach_opts__last_field link_info_len + +LIBBPF_API struct bpf_link * +bpf_program__attach_iter(struct bpf_program *prog, + const struct bpf_iter_attach_opts *opts); + +struct bpf_insn; + +/* + * Libbpf allows callers to adjust BPF programs before being loaded + * into kernel. One program in an object file can be transformed into + * multiple variants to be attached to different hooks. + * + * bpf_program_prep_t, bpf_program__set_prep and bpf_program__nth_fd + * form an API for this purpose. + * + * - bpf_program_prep_t: + * Defines a 'preprocessor', which is a caller defined function + * passed to libbpf through bpf_program__set_prep(), and will be + * called before program is loaded. The processor should adjust + * the program one time for each instance according to the instance id + * passed to it. + * + * - bpf_program__set_prep: + * Attaches a preprocessor to a BPF program. The number of instances + * that should be created is also passed through this function. + * + * - bpf_program__nth_fd: + * After the program is loaded, get resulting FD of a given instance + * of the BPF program. + * + * If bpf_program__set_prep() is not used, the program would be loaded + * without adjustment during bpf_object__load(). The program has only + * one instance. In this case bpf_program__fd(prog) is equal to + * bpf_program__nth_fd(prog, 0). + */ + +struct bpf_prog_prep_result { + /* + * If not NULL, load new instruction array. + * If set to NULL, don't load this instance. + */ + struct bpf_insn *new_insn_ptr; + int new_insn_cnt; + + /* If not NULL, result FD is written to it. */ + int *pfd; +}; + +/* + * Parameters of bpf_program_prep_t: + * - prog: The bpf_program being loaded. + * - n: Index of instance being generated. + * - insns: BPF instructions array. + * - insns_cnt:Number of instructions in insns. + * - res: Output parameter, result of transformation. + * + * Return value: + * - Zero: pre-processing success. + * - Non-zero: pre-processing error, stop loading. + */ +typedef int (*bpf_program_prep_t)(struct bpf_program *prog, int n, + struct bpf_insn *insns, int insns_cnt, + struct bpf_prog_prep_result *res); + +LIBBPF_API int bpf_program__set_prep(struct bpf_program *prog, int nr_instance, + bpf_program_prep_t prep); + +LIBBPF_API int bpf_program__nth_fd(const struct bpf_program *prog, int n); + +/* + * Adjust type of BPF program. Default is kprobe. + */ +LIBBPF_API int bpf_program__set_socket_filter(struct bpf_program *prog); +LIBBPF_API int bpf_program__set_tracepoint(struct bpf_program *prog); +LIBBPF_API int bpf_program__set_raw_tracepoint(struct bpf_program *prog); +LIBBPF_API int bpf_program__set_kprobe(struct bpf_program *prog); +LIBBPF_API int bpf_program__set_lsm(struct bpf_program *prog); +LIBBPF_API int bpf_program__set_sched_cls(struct bpf_program *prog); +LIBBPF_API int bpf_program__set_sched_act(struct bpf_program *prog); +LIBBPF_API int bpf_program__set_xdp(struct bpf_program *prog); +LIBBPF_API int bpf_program__set_perf_event(struct bpf_program *prog); +LIBBPF_API int bpf_program__set_tracing(struct bpf_program *prog); +LIBBPF_API int bpf_program__set_struct_ops(struct bpf_program *prog); +LIBBPF_API int bpf_program__set_extension(struct bpf_program *prog); +LIBBPF_API int bpf_program__set_sk_lookup(struct bpf_program *prog); + +LIBBPF_API enum bpf_prog_type bpf_program__get_type(struct bpf_program *prog); +LIBBPF_API void bpf_program__set_type(struct bpf_program *prog, + enum bpf_prog_type type); + +LIBBPF_API enum bpf_attach_type +bpf_program__get_expected_attach_type(struct bpf_program *prog); +LIBBPF_API void +bpf_program__set_expected_attach_type(struct bpf_program *prog, + enum bpf_attach_type type); + +LIBBPF_API int +bpf_program__set_attach_target(struct bpf_program *prog, int attach_prog_fd, + const char *attach_func_name); + +LIBBPF_API bool bpf_program__is_socket_filter(const struct bpf_program *prog); +LIBBPF_API bool bpf_program__is_tracepoint(const struct bpf_program *prog); +LIBBPF_API bool bpf_program__is_raw_tracepoint(const struct bpf_program *prog); +LIBBPF_API bool bpf_program__is_kprobe(const struct bpf_program *prog); +LIBBPF_API bool bpf_program__is_lsm(const struct bpf_program *prog); +LIBBPF_API bool bpf_program__is_sched_cls(const struct bpf_program *prog); +LIBBPF_API bool bpf_program__is_sched_act(const struct bpf_program *prog); +LIBBPF_API bool bpf_program__is_xdp(const struct bpf_program *prog); +LIBBPF_API bool bpf_program__is_perf_event(const struct bpf_program *prog); +LIBBPF_API bool bpf_program__is_tracing(const struct bpf_program *prog); +LIBBPF_API bool bpf_program__is_struct_ops(const struct bpf_program *prog); +LIBBPF_API bool bpf_program__is_extension(const struct bpf_program *prog); +LIBBPF_API bool bpf_program__is_sk_lookup(const struct bpf_program *prog); + +/* + * No need for __attribute__((packed)), all members of 'bpf_map_def' + * are all aligned. In addition, using __attribute__((packed)) + * would trigger a -Wpacked warning message, and lead to an error + * if -Werror is set. + */ +struct bpf_map_def { + unsigned int type; + unsigned int key_size; + unsigned int value_size; + unsigned int max_entries; + unsigned int map_flags; +}; + +/* + * The 'struct bpf_map' in include/linux/bpf.h is internal to the kernel, + * so no need to worry about a name clash. + */ +LIBBPF_API struct bpf_map * +bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name); + +LIBBPF_API int +bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name); + +/* + * Get bpf_map through the offset of corresponding struct bpf_map_def + * in the BPF object file. + */ +LIBBPF_API struct bpf_map * +bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset); + +LIBBPF_API struct bpf_map * +bpf_map__next(const struct bpf_map *map, const struct bpf_object *obj); +#define bpf_object__for_each_map(pos, obj) \ + for ((pos) = bpf_map__next(NULL, (obj)); \ + (pos) != NULL; \ + (pos) = bpf_map__next((pos), (obj))) +#define bpf_map__for_each bpf_object__for_each_map + +LIBBPF_API struct bpf_map * +bpf_map__prev(const struct bpf_map *map, const struct bpf_object *obj); + +/* get/set map FD */ +LIBBPF_API int bpf_map__fd(const struct bpf_map *map); +LIBBPF_API int bpf_map__reuse_fd(struct bpf_map *map, int fd); +/* get map definition */ +LIBBPF_API const struct bpf_map_def *bpf_map__def(const struct bpf_map *map); +/* get map name */ +LIBBPF_API const char *bpf_map__name(const struct bpf_map *map); +/* get/set map type */ +LIBBPF_API enum bpf_map_type bpf_map__type(const struct bpf_map *map); +LIBBPF_API int bpf_map__set_type(struct bpf_map *map, enum bpf_map_type type); +/* get/set map size (max_entries) */ +LIBBPF_API __u32 bpf_map__max_entries(const struct bpf_map *map); +LIBBPF_API int bpf_map__set_max_entries(struct bpf_map *map, __u32 max_entries); +LIBBPF_API int bpf_map__resize(struct bpf_map *map, __u32 max_entries); +/* get/set map flags */ +LIBBPF_API __u32 bpf_map__map_flags(const struct bpf_map *map); +LIBBPF_API int bpf_map__set_map_flags(struct bpf_map *map, __u32 flags); +/* get/set map NUMA node */ +LIBBPF_API __u32 bpf_map__numa_node(const struct bpf_map *map); +LIBBPF_API int bpf_map__set_numa_node(struct bpf_map *map, __u32 numa_node); +/* get/set map key size */ +LIBBPF_API __u32 bpf_map__key_size(const struct bpf_map *map); +LIBBPF_API int bpf_map__set_key_size(struct bpf_map *map, __u32 size); +/* get/set map value size */ +LIBBPF_API __u32 bpf_map__value_size(const struct bpf_map *map); +LIBBPF_API int bpf_map__set_value_size(struct bpf_map *map, __u32 size); +/* get map key/value BTF type IDs */ +LIBBPF_API __u32 bpf_map__btf_key_type_id(const struct bpf_map *map); +LIBBPF_API __u32 bpf_map__btf_value_type_id(const struct bpf_map *map); +/* get/set map if_index */ +LIBBPF_API __u32 bpf_map__ifindex(const struct bpf_map *map); +LIBBPF_API int bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex); + +typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *); +LIBBPF_API int bpf_map__set_priv(struct bpf_map *map, void *priv, + bpf_map_clear_priv_t clear_priv); +LIBBPF_API void *bpf_map__priv(const struct bpf_map *map); +LIBBPF_API int bpf_map__set_initial_value(struct bpf_map *map, + const void *data, size_t size); +LIBBPF_API bool bpf_map__is_offload_neutral(const struct bpf_map *map); +LIBBPF_API bool bpf_map__is_internal(const struct bpf_map *map); +LIBBPF_API int bpf_map__set_pin_path(struct bpf_map *map, const char *path); +LIBBPF_API const char *bpf_map__get_pin_path(const struct bpf_map *map); +LIBBPF_API bool bpf_map__is_pinned(const struct bpf_map *map); +LIBBPF_API int bpf_map__pin(struct bpf_map *map, const char *path); +LIBBPF_API int bpf_map__unpin(struct bpf_map *map, const char *path); + +LIBBPF_API int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd); + +LIBBPF_API long libbpf_get_error(const void *ptr); + +struct bpf_prog_load_attr { + const char *file; + enum bpf_prog_type prog_type; + enum bpf_attach_type expected_attach_type; + int ifindex; + int log_level; + int prog_flags; +}; + +LIBBPF_API int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr, + struct bpf_object **pobj, int *prog_fd); +LIBBPF_API int bpf_prog_load(const char *file, enum bpf_prog_type type, + struct bpf_object **pobj, int *prog_fd); + +struct xdp_link_info { + __u32 prog_id; + __u32 drv_prog_id; + __u32 hw_prog_id; + __u32 skb_prog_id; + __u8 attach_mode; +}; + +struct bpf_xdp_set_link_opts { + size_t sz; + int old_fd; + size_t :0; +}; +#define bpf_xdp_set_link_opts__last_field old_fd + +LIBBPF_API int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags); +LIBBPF_API int bpf_set_link_xdp_fd_opts(int ifindex, int fd, __u32 flags, + const struct bpf_xdp_set_link_opts *opts); +LIBBPF_API int bpf_get_link_xdp_id(int ifindex, __u32 *prog_id, __u32 flags); +LIBBPF_API int bpf_get_link_xdp_info(int ifindex, struct xdp_link_info *info, + size_t info_size, __u32 flags); + +/* Ring buffer APIs */ +struct ring_buffer; + +typedef int (*ring_buffer_sample_fn)(void *ctx, void *data, size_t size); + +struct ring_buffer_opts { + size_t sz; /* size of this struct, for forward/backward compatiblity */ +}; + +#define ring_buffer_opts__last_field sz + +LIBBPF_API struct ring_buffer * +ring_buffer__new(int map_fd, ring_buffer_sample_fn sample_cb, void *ctx, + const struct ring_buffer_opts *opts); +LIBBPF_API void ring_buffer__free(struct ring_buffer *rb); +LIBBPF_API int ring_buffer__add(struct ring_buffer *rb, int map_fd, + ring_buffer_sample_fn sample_cb, void *ctx); +LIBBPF_API int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms); +LIBBPF_API int ring_buffer__consume(struct ring_buffer *rb); + +/* Perf buffer APIs */ +struct perf_buffer; + +typedef void (*perf_buffer_sample_fn)(void *ctx, int cpu, + void *data, __u32 size); +typedef void (*perf_buffer_lost_fn)(void *ctx, int cpu, __u64 cnt); + +/* common use perf buffer options */ +struct perf_buffer_opts { + /* if specified, sample_cb is called for each sample */ + perf_buffer_sample_fn sample_cb; + /* if specified, lost_cb is called for each batch of lost samples */ + perf_buffer_lost_fn lost_cb; + /* ctx is provided to sample_cb and lost_cb */ + void *ctx; +}; + +LIBBPF_API struct perf_buffer * +perf_buffer__new(int map_fd, size_t page_cnt, + const struct perf_buffer_opts *opts); + +enum bpf_perf_event_ret { + LIBBPF_PERF_EVENT_DONE = 0, + LIBBPF_PERF_EVENT_ERROR = -1, + LIBBPF_PERF_EVENT_CONT = -2, +}; + +struct perf_event_header; + +typedef enum bpf_perf_event_ret +(*perf_buffer_event_fn)(void *ctx, int cpu, struct perf_event_header *event); + +/* raw perf buffer options, giving most power and control */ +struct perf_buffer_raw_opts { + /* perf event attrs passed directly into perf_event_open() */ + struct perf_event_attr *attr; + /* raw event callback */ + perf_buffer_event_fn event_cb; + /* ctx is provided to event_cb */ + void *ctx; + /* if cpu_cnt == 0, open all on all possible CPUs (up to the number of + * max_entries of given PERF_EVENT_ARRAY map) + */ + int cpu_cnt; + /* if cpu_cnt > 0, cpus is an array of CPUs to open ring buffers on */ + int *cpus; + /* if cpu_cnt > 0, map_keys specify map keys to set per-CPU FDs for */ + int *map_keys; +}; + +LIBBPF_API struct perf_buffer * +perf_buffer__new_raw(int map_fd, size_t page_cnt, + const struct perf_buffer_raw_opts *opts); + +LIBBPF_API void perf_buffer__free(struct perf_buffer *pb); +LIBBPF_API int perf_buffer__epoll_fd(const struct perf_buffer *pb); +LIBBPF_API int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms); +LIBBPF_API int perf_buffer__consume(struct perf_buffer *pb); +LIBBPF_API int perf_buffer__consume_buffer(struct perf_buffer *pb, size_t buf_idx); +LIBBPF_API size_t perf_buffer__buffer_cnt(const struct perf_buffer *pb); +LIBBPF_API int perf_buffer__buffer_fd(const struct perf_buffer *pb, size_t buf_idx); + +typedef enum bpf_perf_event_ret + (*bpf_perf_event_print_t)(struct perf_event_header *hdr, + void *private_data); +LIBBPF_API enum bpf_perf_event_ret +bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size, + void **copy_mem, size_t *copy_size, + bpf_perf_event_print_t fn, void *private_data); + +struct bpf_prog_linfo; +struct bpf_prog_info; + +LIBBPF_API void bpf_prog_linfo__free(struct bpf_prog_linfo *prog_linfo); +LIBBPF_API struct bpf_prog_linfo * +bpf_prog_linfo__new(const struct bpf_prog_info *info); +LIBBPF_API const struct bpf_line_info * +bpf_prog_linfo__lfind_addr_func(const struct bpf_prog_linfo *prog_linfo, + __u64 addr, __u32 func_idx, __u32 nr_skip); +LIBBPF_API const struct bpf_line_info * +bpf_prog_linfo__lfind(const struct bpf_prog_linfo *prog_linfo, + __u32 insn_off, __u32 nr_skip); + +/* + * Probe for supported system features + * + * Note that running many of these probes in a short amount of time can cause + * the kernel to reach the maximal size of lockable memory allowed for the + * user, causing subsequent probes to fail. In this case, the caller may want + * to adjust that limit with setrlimit(). + */ +LIBBPF_API bool bpf_probe_prog_type(enum bpf_prog_type prog_type, + __u32 ifindex); +LIBBPF_API bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex); +LIBBPF_API bool bpf_probe_helper(enum bpf_func_id id, + enum bpf_prog_type prog_type, __u32 ifindex); +LIBBPF_API bool bpf_probe_large_insn_limit(__u32 ifindex); + +/* + * Get bpf_prog_info in continuous memory + * + * struct bpf_prog_info has multiple arrays. The user has option to choose + * arrays to fetch from kernel. The following APIs provide an uniform way to + * fetch these data. All arrays in bpf_prog_info are stored in a single + * continuous memory region. This makes it easy to store the info in a + * file. + * + * Before writing bpf_prog_info_linear to files, it is necessary to + * translate pointers in bpf_prog_info to offsets. Helper functions + * bpf_program__bpil_addr_to_offs() and bpf_program__bpil_offs_to_addr() + * are introduced to switch between pointers and offsets. + * + * Examples: + * # To fetch map_ids and prog_tags: + * __u64 arrays = (1UL << BPF_PROG_INFO_MAP_IDS) | + * (1UL << BPF_PROG_INFO_PROG_TAGS); + * struct bpf_prog_info_linear *info_linear = + * bpf_program__get_prog_info_linear(fd, arrays); + * + * # To save data in file + * bpf_program__bpil_addr_to_offs(info_linear); + * write(f, info_linear, sizeof(*info_linear) + info_linear->data_len); + * + * # To read data from file + * read(f, info_linear, <proper_size>); + * bpf_program__bpil_offs_to_addr(info_linear); + */ +enum bpf_prog_info_array { + BPF_PROG_INFO_FIRST_ARRAY = 0, + BPF_PROG_INFO_JITED_INSNS = 0, + BPF_PROG_INFO_XLATED_INSNS, + BPF_PROG_INFO_MAP_IDS, + BPF_PROG_INFO_JITED_KSYMS, + BPF_PROG_INFO_JITED_FUNC_LENS, + BPF_PROG_INFO_FUNC_INFO, + BPF_PROG_INFO_LINE_INFO, + BPF_PROG_INFO_JITED_LINE_INFO, + BPF_PROG_INFO_PROG_TAGS, + BPF_PROG_INFO_LAST_ARRAY, +}; + +struct bpf_prog_info_linear { + /* size of struct bpf_prog_info, when the tool is compiled */ + __u32 info_len; + /* total bytes allocated for data, round up to 8 bytes */ + __u32 data_len; + /* which arrays are included in data */ + __u64 arrays; + struct bpf_prog_info info; + __u8 data[]; +}; + +LIBBPF_API struct bpf_prog_info_linear * +bpf_program__get_prog_info_linear(int fd, __u64 arrays); + +LIBBPF_API void +bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear); + +LIBBPF_API void +bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear); + +/* + * A helper function to get the number of possible CPUs before looking up + * per-CPU maps. Negative errno is returned on failure. + * + * Example usage: + * + * int ncpus = libbpf_num_possible_cpus(); + * if (ncpus < 0) { + * // error handling + * } + * long values[ncpus]; + * bpf_map_lookup_elem(per_cpu_map_fd, key, values); + * + */ +LIBBPF_API int libbpf_num_possible_cpus(void); + +struct bpf_map_skeleton { + const char *name; + struct bpf_map **map; + void **mmaped; +}; + +struct bpf_prog_skeleton { + const char *name; + struct bpf_program **prog; + struct bpf_link **link; +}; + +struct bpf_object_skeleton { + size_t sz; /* size of this struct, for forward/backward compatibility */ + + const char *name; + void *data; + size_t data_sz; + + struct bpf_object **obj; + + int map_cnt; + int map_skel_sz; /* sizeof(struct bpf_skeleton_map) */ + struct bpf_map_skeleton *maps; + + int prog_cnt; + int prog_skel_sz; /* sizeof(struct bpf_skeleton_prog) */ + struct bpf_prog_skeleton *progs; +}; + +LIBBPF_API int +bpf_object__open_skeleton(struct bpf_object_skeleton *s, + const struct bpf_object_open_opts *opts); +LIBBPF_API int bpf_object__load_skeleton(struct bpf_object_skeleton *s); +LIBBPF_API int bpf_object__attach_skeleton(struct bpf_object_skeleton *s); +LIBBPF_API void bpf_object__detach_skeleton(struct bpf_object_skeleton *s); +LIBBPF_API void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s); + +enum libbpf_tristate { + TRI_NO = 0, + TRI_YES = 1, + TRI_MODULE = 2, +}; + +#ifdef __cplusplus +} /* extern "C" */ +#endif + +#endif /* __LIBBPF_LIBBPF_H */ diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map new file mode 100644 index 000000000..4ebfadf45 --- /dev/null +++ b/tools/lib/bpf/libbpf.map @@ -0,0 +1,339 @@ +LIBBPF_0.0.1 { + global: + bpf_btf_get_fd_by_id; + bpf_create_map; + bpf_create_map_in_map; + bpf_create_map_in_map_node; + bpf_create_map_name; + bpf_create_map_node; + bpf_create_map_xattr; + bpf_load_btf; + bpf_load_program; + bpf_load_program_xattr; + bpf_map__btf_key_type_id; + bpf_map__btf_value_type_id; + bpf_map__def; + bpf_map__fd; + bpf_map__is_offload_neutral; + bpf_map__name; + bpf_map__next; + bpf_map__pin; + bpf_map__prev; + bpf_map__priv; + bpf_map__reuse_fd; + bpf_map__set_ifindex; + bpf_map__set_inner_map_fd; + bpf_map__set_priv; + bpf_map__unpin; + bpf_map_delete_elem; + bpf_map_get_fd_by_id; + bpf_map_get_next_id; + bpf_map_get_next_key; + bpf_map_lookup_and_delete_elem; + bpf_map_lookup_elem; + bpf_map_update_elem; + bpf_obj_get; + bpf_obj_get_info_by_fd; + bpf_obj_pin; + bpf_object__btf_fd; + bpf_object__close; + bpf_object__find_map_by_name; + bpf_object__find_map_by_offset; + bpf_object__find_program_by_title; + bpf_object__kversion; + bpf_object__load; + bpf_object__name; + bpf_object__next; + bpf_object__open; + bpf_object__open_buffer; + bpf_object__open_xattr; + bpf_object__pin; + bpf_object__pin_maps; + bpf_object__pin_programs; + bpf_object__priv; + bpf_object__set_priv; + bpf_object__unload; + bpf_object__unpin_maps; + bpf_object__unpin_programs; + bpf_perf_event_read_simple; + bpf_prog_attach; + bpf_prog_detach; + bpf_prog_detach2; + bpf_prog_get_fd_by_id; + bpf_prog_get_next_id; + bpf_prog_load; + bpf_prog_load_xattr; + bpf_prog_query; + bpf_prog_test_run; + bpf_prog_test_run_xattr; + bpf_program__fd; + bpf_program__is_kprobe; + bpf_program__is_perf_event; + bpf_program__is_raw_tracepoint; + bpf_program__is_sched_act; + bpf_program__is_sched_cls; + bpf_program__is_socket_filter; + bpf_program__is_tracepoint; + bpf_program__is_xdp; + bpf_program__load; + bpf_program__next; + bpf_program__nth_fd; + bpf_program__pin; + bpf_program__pin_instance; + bpf_program__prev; + bpf_program__priv; + bpf_program__set_expected_attach_type; + bpf_program__set_ifindex; + bpf_program__set_kprobe; + bpf_program__set_perf_event; + bpf_program__set_prep; + bpf_program__set_priv; + bpf_program__set_raw_tracepoint; + bpf_program__set_sched_act; + bpf_program__set_sched_cls; + bpf_program__set_socket_filter; + bpf_program__set_tracepoint; + bpf_program__set_type; + bpf_program__set_xdp; + bpf_program__title; + bpf_program__unload; + bpf_program__unpin; + bpf_program__unpin_instance; + bpf_prog_linfo__free; + bpf_prog_linfo__new; + bpf_prog_linfo__lfind_addr_func; + bpf_prog_linfo__lfind; + bpf_raw_tracepoint_open; + bpf_set_link_xdp_fd; + bpf_task_fd_query; + bpf_verify_program; + btf__fd; + btf__find_by_name; + btf__free; + btf__get_from_id; + btf__name_by_offset; + btf__new; + btf__resolve_size; + btf__resolve_type; + btf__type_by_id; + libbpf_attach_type_by_name; + libbpf_get_error; + libbpf_prog_type_by_name; + libbpf_set_print; + libbpf_strerror; + local: + *; +}; + +LIBBPF_0.0.2 { + global: + bpf_probe_helper; + bpf_probe_map_type; + bpf_probe_prog_type; + bpf_map__resize; + bpf_map_lookup_elem_flags; + bpf_object__btf; + bpf_object__find_map_fd_by_name; + bpf_get_link_xdp_id; + btf__dedup; + btf__get_map_kv_tids; + btf__get_nr_types; + btf__get_raw_data; + btf__load; + btf_ext__free; + btf_ext__func_info_rec_size; + btf_ext__get_raw_data; + btf_ext__line_info_rec_size; + btf_ext__new; + btf_ext__reloc_func_info; + btf_ext__reloc_line_info; + xsk_umem__create; + xsk_socket__create; + xsk_umem__delete; + xsk_socket__delete; + xsk_umem__fd; + xsk_socket__fd; + bpf_program__get_prog_info_linear; + bpf_program__bpil_addr_to_offs; + bpf_program__bpil_offs_to_addr; +} LIBBPF_0.0.1; + +LIBBPF_0.0.3 { + global: + bpf_map__is_internal; + bpf_map_freeze; + btf__finalize_data; +} LIBBPF_0.0.2; + +LIBBPF_0.0.4 { + global: + bpf_link__destroy; + bpf_object__load_xattr; + bpf_program__attach_kprobe; + bpf_program__attach_perf_event; + bpf_program__attach_raw_tracepoint; + bpf_program__attach_tracepoint; + bpf_program__attach_uprobe; + btf_dump__dump_type; + btf_dump__free; + btf_dump__new; + btf__parse_elf; + libbpf_num_possible_cpus; + perf_buffer__free; + perf_buffer__new; + perf_buffer__new_raw; + perf_buffer__poll; + xsk_umem__create; +} LIBBPF_0.0.3; + +LIBBPF_0.0.5 { + global: + bpf_btf_get_next_id; +} LIBBPF_0.0.4; + +LIBBPF_0.0.6 { + global: + bpf_get_link_xdp_info; + bpf_map__get_pin_path; + bpf_map__is_pinned; + bpf_map__set_pin_path; + bpf_object__open_file; + bpf_object__open_mem; + bpf_program__attach_trace; + bpf_program__get_expected_attach_type; + bpf_program__get_type; + bpf_program__is_tracing; + bpf_program__set_tracing; + bpf_program__size; + btf__find_by_name_kind; + libbpf_find_vmlinux_btf_id; +} LIBBPF_0.0.5; + +LIBBPF_0.0.7 { + global: + btf_dump__emit_type_decl; + bpf_link__disconnect; + bpf_map__attach_struct_ops; + bpf_map_delete_batch; + bpf_map_lookup_and_delete_batch; + bpf_map_lookup_batch; + bpf_map_update_batch; + bpf_object__find_program_by_name; + bpf_object__attach_skeleton; + bpf_object__destroy_skeleton; + bpf_object__detach_skeleton; + bpf_object__load_skeleton; + bpf_object__open_skeleton; + bpf_probe_large_insn_limit; + bpf_prog_attach_xattr; + bpf_program__attach; + bpf_program__name; + bpf_program__is_extension; + bpf_program__is_struct_ops; + bpf_program__set_extension; + bpf_program__set_struct_ops; + btf__align_of; + libbpf_find_kernel_btf; +} LIBBPF_0.0.6; + +LIBBPF_0.0.8 { + global: + bpf_link__fd; + bpf_link__open; + bpf_link__pin; + bpf_link__pin_path; + bpf_link__unpin; + bpf_link__update_program; + bpf_link_create; + bpf_link_update; + bpf_map__set_initial_value; + bpf_program__attach_cgroup; + bpf_program__attach_lsm; + bpf_program__is_lsm; + bpf_program__set_attach_target; + bpf_program__set_lsm; + bpf_set_link_xdp_fd_opts; +} LIBBPF_0.0.7; + +LIBBPF_0.0.9 { + global: + bpf_enable_stats; + bpf_iter_create; + bpf_link_get_fd_by_id; + bpf_link_get_next_id; + bpf_program__attach_iter; + bpf_program__attach_netns; + perf_buffer__consume; + ring_buffer__add; + ring_buffer__consume; + ring_buffer__free; + ring_buffer__new; + ring_buffer__poll; +} LIBBPF_0.0.8; + +LIBBPF_0.1.0 { + global: + bpf_link__detach; + bpf_link_detach; + bpf_map__ifindex; + bpf_map__key_size; + bpf_map__map_flags; + bpf_map__max_entries; + bpf_map__numa_node; + bpf_map__set_key_size; + bpf_map__set_map_flags; + bpf_map__set_max_entries; + bpf_map__set_numa_node; + bpf_map__set_type; + bpf_map__set_value_size; + bpf_map__type; + bpf_map__value_size; + bpf_program__attach_xdp; + bpf_program__autoload; + bpf_program__is_sk_lookup; + bpf_program__set_autoload; + bpf_program__set_sk_lookup; + btf__parse; + btf__parse_raw; + btf__pointer_size; + btf__set_fd; + btf__set_pointer_size; +} LIBBPF_0.0.9; + +LIBBPF_0.2.0 { + global: + bpf_prog_bind_map; + bpf_prog_test_run_opts; + bpf_program__attach_freplace; + bpf_program__section_name; + btf__add_array; + btf__add_const; + btf__add_enum; + btf__add_enum_value; + btf__add_datasec; + btf__add_datasec_var_info; + btf__add_field; + btf__add_func; + btf__add_func_param; + btf__add_func_proto; + btf__add_fwd; + btf__add_int; + btf__add_ptr; + btf__add_restrict; + btf__add_str; + btf__add_struct; + btf__add_typedef; + btf__add_union; + btf__add_var; + btf__add_volatile; + btf__endianness; + btf__find_str; + btf__new_empty; + btf__set_endianness; + btf__str_by_offset; + perf_buffer__buffer_cnt; + perf_buffer__buffer_fd; + perf_buffer__epoll_fd; + perf_buffer__consume_buffer; + xsk_socket__create_shared; +} LIBBPF_0.1.0; diff --git a/tools/lib/bpf/libbpf.pc.template b/tools/lib/bpf/libbpf.pc.template new file mode 100644 index 000000000..b45ed534b --- /dev/null +++ b/tools/lib/bpf/libbpf.pc.template @@ -0,0 +1,12 @@ +# SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) + +prefix=@PREFIX@ +libdir=@LIBDIR@ +includedir=${prefix}/include + +Name: libbpf +Description: BPF library +Version: @VERSION@ +Libs: -L${libdir} -lbpf +Requires.private: libelf zlib +Cflags: -I${includedir} diff --git a/tools/lib/bpf/libbpf_common.h b/tools/lib/bpf/libbpf_common.h new file mode 100644 index 000000000..947d8bd8a --- /dev/null +++ b/tools/lib/bpf/libbpf_common.h @@ -0,0 +1,42 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ + +/* + * Common user-facing libbpf helpers. + * + * Copyright (c) 2019 Facebook + */ + +#ifndef __LIBBPF_LIBBPF_COMMON_H +#define __LIBBPF_LIBBPF_COMMON_H + +#include <string.h> + +#ifndef LIBBPF_API +#define LIBBPF_API __attribute__((visibility("default"))) +#endif + +#define LIBBPF_DEPRECATED(msg) __attribute__((deprecated(msg))) + +/* Helper macro to declare and initialize libbpf options struct + * + * This dance with uninitialized declaration, followed by memset to zero, + * followed by assignment using compound literal syntax is done to preserve + * ability to use a nice struct field initialization syntax and **hopefully** + * have all the padding bytes initialized to zero. It's not guaranteed though, + * when copying literal, that compiler won't copy garbage in literal's padding + * bytes, but that's the best way I've found and it seems to work in practice. + * + * Macro declares opts struct of given type and name, zero-initializes, + * including any extra padding, it with memset() and then assigns initial + * values provided by users in struct initializer-syntax as varargs. + */ +#define DECLARE_LIBBPF_OPTS(TYPE, NAME, ...) \ + struct TYPE NAME = ({ \ + memset(&NAME, 0, sizeof(struct TYPE)); \ + (struct TYPE) { \ + .sz = sizeof(struct TYPE), \ + __VA_ARGS__ \ + }; \ + }) + +#endif /* __LIBBPF_LIBBPF_COMMON_H */ diff --git a/tools/lib/bpf/libbpf_errno.c b/tools/lib/bpf/libbpf_errno.c new file mode 100644 index 000000000..0afb51f7a --- /dev/null +++ b/tools/lib/bpf/libbpf_errno.c @@ -0,0 +1,66 @@ +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) + +/* + * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org> + * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com> + * Copyright (C) 2015 Huawei Inc. + * Copyright (C) 2017 Nicira, Inc. + */ + +#undef _GNU_SOURCE +#include <stdio.h> +#include <string.h> + +#include "libbpf.h" + +/* make sure libbpf doesn't use kernel-only integer typedefs */ +#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 + +#define ERRNO_OFFSET(e) ((e) - __LIBBPF_ERRNO__START) +#define ERRCODE_OFFSET(c) ERRNO_OFFSET(LIBBPF_ERRNO__##c) +#define NR_ERRNO (__LIBBPF_ERRNO__END - __LIBBPF_ERRNO__START) + +static const char *libbpf_strerror_table[NR_ERRNO] = { + [ERRCODE_OFFSET(LIBELF)] = "Something wrong in libelf", + [ERRCODE_OFFSET(FORMAT)] = "BPF object format invalid", + [ERRCODE_OFFSET(KVERSION)] = "'version' section incorrect or lost", + [ERRCODE_OFFSET(ENDIAN)] = "Endian mismatch", + [ERRCODE_OFFSET(INTERNAL)] = "Internal error in libbpf", + [ERRCODE_OFFSET(RELOC)] = "Relocation failed", + [ERRCODE_OFFSET(VERIFY)] = "Kernel verifier blocks program loading", + [ERRCODE_OFFSET(PROG2BIG)] = "Program too big", + [ERRCODE_OFFSET(KVER)] = "Incorrect kernel version", + [ERRCODE_OFFSET(PROGTYPE)] = "Kernel doesn't support this program type", + [ERRCODE_OFFSET(WRNGPID)] = "Wrong pid in netlink message", + [ERRCODE_OFFSET(INVSEQ)] = "Invalid netlink sequence", + [ERRCODE_OFFSET(NLPARSE)] = "Incorrect netlink message parsing", +}; + +int libbpf_strerror(int err, char *buf, size_t size) +{ + if (!buf || !size) + return -1; + + err = err > 0 ? err : -err; + + if (err < __LIBBPF_ERRNO__START) { + int ret; + + ret = strerror_r(err, buf, size); + buf[size - 1] = '\0'; + return ret; + } + + if (err < __LIBBPF_ERRNO__END) { + const char *msg; + + msg = libbpf_strerror_table[ERRNO_OFFSET(err)]; + snprintf(buf, size, "%s", msg); + buf[size - 1] = '\0'; + return 0; + } + + snprintf(buf, size, "Unknown libbpf error %d", err); + buf[size - 1] = '\0'; + return -1; +} diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h new file mode 100644 index 000000000..d99bc847b --- /dev/null +++ b/tools/lib/bpf/libbpf_internal.h @@ -0,0 +1,321 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ + +/* + * Internal libbpf helpers. + * + * Copyright (c) 2019 Facebook + */ + +#ifndef __LIBBPF_LIBBPF_INTERNAL_H +#define __LIBBPF_LIBBPF_INTERNAL_H + +#include <stdlib.h> +#include <limits.h> + +/* make sure libbpf doesn't use kernel-only integer typedefs */ +#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 + +/* prevent accidental re-addition of reallocarray() */ +#pragma GCC poison reallocarray + +#include "libbpf.h" + +#define BTF_INFO_ENC(kind, kind_flag, vlen) \ + ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN)) +#define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type) +#define BTF_INT_ENC(encoding, bits_offset, nr_bits) \ + ((encoding) << 24 | (bits_offset) << 16 | (nr_bits)) +#define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \ + BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \ + BTF_INT_ENC(encoding, bits_offset, bits) +#define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset) +#define BTF_PARAM_ENC(name, type) (name), (type) +#define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size) + +#ifndef likely +#define likely(x) __builtin_expect(!!(x), 1) +#endif +#ifndef unlikely +#define unlikely(x) __builtin_expect(!!(x), 0) +#endif +#ifndef min +# define min(x, y) ((x) < (y) ? (x) : (y)) +#endif +#ifndef max +# define max(x, y) ((x) < (y) ? (y) : (x)) +#endif +#ifndef offsetofend +# define offsetofend(TYPE, FIELD) \ + (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD)) +#endif + +/* Symbol versioning is different between static and shared library. + * Properly versioned symbols are needed for shared library, but + * only the symbol of the new version is needed for static library. + */ +#ifdef SHARED +# define COMPAT_VERSION(internal_name, api_name, version) \ + asm(".symver " #internal_name "," #api_name "@" #version); +# define DEFAULT_VERSION(internal_name, api_name, version) \ + asm(".symver " #internal_name "," #api_name "@@" #version); +#else +# define COMPAT_VERSION(internal_name, api_name, version) +# define DEFAULT_VERSION(internal_name, api_name, version) \ + extern typeof(internal_name) api_name \ + __attribute__((alias(#internal_name))); +#endif + +extern void libbpf_print(enum libbpf_print_level level, + const char *format, ...) + __attribute__((format(printf, 2, 3))); + +#define __pr(level, fmt, ...) \ +do { \ + libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \ +} while (0) + +#define pr_warn(fmt, ...) __pr(LIBBPF_WARN, fmt, ##__VA_ARGS__) +#define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__) +#define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__) + +#ifndef __has_builtin +#define __has_builtin(x) 0 +#endif +/* + * Re-implement glibc's reallocarray() for libbpf internal-only use. + * reallocarray(), unfortunately, is not available in all versions of glibc, + * so requires extra feature detection and using reallocarray() stub from + * <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates + * build of libbpf unnecessarily and is just a maintenance burden. Instead, + * it's trivial to implement libbpf-specific internal version and use it + * throughout libbpf. + */ +static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size) +{ + size_t total; + +#if __has_builtin(__builtin_mul_overflow) + if (unlikely(__builtin_mul_overflow(nmemb, size, &total))) + return NULL; +#else + if (size == 0 || nmemb > ULONG_MAX / size) + return NULL; + total = nmemb * size; +#endif + return realloc(ptr, total); +} + +void *btf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, + size_t cur_cnt, size_t max_cnt, size_t add_cnt); +int btf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt); + +static inline bool libbpf_validate_opts(const char *opts, + size_t opts_sz, size_t user_sz, + const char *type_name) +{ + if (user_sz < sizeof(size_t)) { + pr_warn("%s size (%zu) is too small\n", type_name, user_sz); + return false; + } + if (user_sz > opts_sz) { + size_t i; + + for (i = opts_sz; i < user_sz; i++) { + if (opts[i]) { + pr_warn("%s has non-zero extra bytes\n", + type_name); + return false; + } + } + } + return true; +} + +#define OPTS_VALID(opts, type) \ + (!(opts) || libbpf_validate_opts((const char *)opts, \ + offsetofend(struct type, \ + type##__last_field), \ + (opts)->sz, #type)) +#define OPTS_HAS(opts, field) \ + ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field)) +#define OPTS_GET(opts, field, fallback_value) \ + (OPTS_HAS(opts, field) ? (opts)->field : fallback_value) +#define OPTS_SET(opts, field, value) \ + do { \ + if (OPTS_HAS(opts, field)) \ + (opts)->field = value; \ + } while (0) + +int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz); +int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz); +int libbpf__load_raw_btf(const char *raw_types, size_t types_len, + const char *str_sec, size_t str_len); + +int bpf_object__section_size(const struct bpf_object *obj, const char *name, + __u32 *size); +int bpf_object__variable_offset(const struct bpf_object *obj, const char *name, + __u32 *off); + +struct btf_ext_info { + /* + * info points to the individual info section (e.g. func_info and + * line_info) from the .BTF.ext. It does not include the __u32 rec_size. + */ + void *info; + __u32 rec_size; + __u32 len; +}; + +#define for_each_btf_ext_sec(seg, sec) \ + for (sec = (seg)->info; \ + (void *)sec < (seg)->info + (seg)->len; \ + sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \ + (seg)->rec_size * sec->num_info) + +#define for_each_btf_ext_rec(seg, sec, i, rec) \ + for (i = 0, rec = (void *)&(sec)->data; \ + i < (sec)->num_info; \ + i++, rec = (void *)rec + (seg)->rec_size) + +/* + * The .BTF.ext ELF section layout defined as + * struct btf_ext_header + * func_info subsection + * + * The func_info subsection layout: + * record size for struct bpf_func_info in the func_info subsection + * struct btf_sec_func_info for section #1 + * a list of bpf_func_info records for section #1 + * where struct bpf_func_info mimics one in include/uapi/linux/bpf.h + * but may not be identical + * struct btf_sec_func_info for section #2 + * a list of bpf_func_info records for section #2 + * ...... + * + * Note that the bpf_func_info record size in .BTF.ext may not + * be the same as the one defined in include/uapi/linux/bpf.h. + * The loader should ensure that record_size meets minimum + * requirement and pass the record as is to the kernel. The + * kernel will handle the func_info properly based on its contents. + */ +struct btf_ext_header { + __u16 magic; + __u8 version; + __u8 flags; + __u32 hdr_len; + + /* All offsets are in bytes relative to the end of this header */ + __u32 func_info_off; + __u32 func_info_len; + __u32 line_info_off; + __u32 line_info_len; + + /* optional part of .BTF.ext header */ + __u32 core_relo_off; + __u32 core_relo_len; +}; + +struct btf_ext { + union { + struct btf_ext_header *hdr; + void *data; + }; + struct btf_ext_info func_info; + struct btf_ext_info line_info; + struct btf_ext_info core_relo_info; + __u32 data_size; +}; + +struct btf_ext_info_sec { + __u32 sec_name_off; + __u32 num_info; + /* Followed by num_info * record_size number of bytes */ + __u8 data[]; +}; + +/* The minimum bpf_func_info checked by the loader */ +struct bpf_func_info_min { + __u32 insn_off; + __u32 type_id; +}; + +/* The minimum bpf_line_info checked by the loader */ +struct bpf_line_info_min { + __u32 insn_off; + __u32 file_name_off; + __u32 line_off; + __u32 line_col; +}; + +/* bpf_core_relo_kind encodes which aspect of captured field/type/enum value + * has to be adjusted by relocations. + */ +enum bpf_core_relo_kind { + BPF_FIELD_BYTE_OFFSET = 0, /* field byte offset */ + BPF_FIELD_BYTE_SIZE = 1, /* field size in bytes */ + BPF_FIELD_EXISTS = 2, /* field existence in target kernel */ + BPF_FIELD_SIGNED = 3, /* field signedness (0 - unsigned, 1 - signed) */ + BPF_FIELD_LSHIFT_U64 = 4, /* bitfield-specific left bitshift */ + BPF_FIELD_RSHIFT_U64 = 5, /* bitfield-specific right bitshift */ + BPF_TYPE_ID_LOCAL = 6, /* type ID in local BPF object */ + BPF_TYPE_ID_TARGET = 7, /* type ID in target kernel */ + BPF_TYPE_EXISTS = 8, /* type existence in target kernel */ + BPF_TYPE_SIZE = 9, /* type size in bytes */ + BPF_ENUMVAL_EXISTS = 10, /* enum value existence in target kernel */ + BPF_ENUMVAL_VALUE = 11, /* enum value integer value */ +}; + +/* The minimum bpf_core_relo checked by the loader + * + * CO-RE relocation captures the following data: + * - insn_off - instruction offset (in bytes) within a BPF program that needs + * its insn->imm field to be relocated with actual field info; + * - type_id - BTF type ID of the "root" (containing) entity of a relocatable + * type or field; + * - access_str_off - offset into corresponding .BTF string section. String + * interpretation depends on specific relocation kind: + * - for field-based relocations, string encodes an accessed field using + * a sequence of field and array indices, separated by colon (:). It's + * conceptually very close to LLVM's getelementptr ([0]) instruction's + * arguments for identifying offset to a field. + * - for type-based relocations, strings is expected to be just "0"; + * - for enum value-based relocations, string contains an index of enum + * value within its enum type; + * + * Example to provide a better feel. + * + * struct sample { + * int a; + * struct { + * int b[10]; + * }; + * }; + * + * struct sample *s = ...; + * int x = &s->a; // encoded as "0:0" (a is field #0) + * int y = &s->b[5]; // encoded as "0:1:0:5" (anon struct is field #1, + * // b is field #0 inside anon struct, accessing elem #5) + * int z = &s[10]->b; // encoded as "10:1" (ptr is used as an array) + * + * type_id for all relocs in this example will capture BTF type id of + * `struct sample`. + * + * Such relocation is emitted when using __builtin_preserve_access_index() + * Clang built-in, passing expression that captures field address, e.g.: + * + * bpf_probe_read(&dst, sizeof(dst), + * __builtin_preserve_access_index(&src->a.b.c)); + * + * In this case Clang will emit field relocation recording necessary data to + * be able to find offset of embedded `a.b.c` field within `src` struct. + * + * [0] https://llvm.org/docs/LangRef.html#getelementptr-instruction + */ +struct bpf_core_relo { + __u32 insn_off; + __u32 type_id; + __u32 access_str_off; + enum bpf_core_relo_kind kind; +}; + +#endif /* __LIBBPF_LIBBPF_INTERNAL_H */ diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c new file mode 100644 index 000000000..13393f0ea --- /dev/null +++ b/tools/lib/bpf/libbpf_probes.c @@ -0,0 +1,359 @@ +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) +/* Copyright (c) 2019 Netronome Systems, Inc. */ + +#include <errno.h> +#include <fcntl.h> +#include <string.h> +#include <stdlib.h> +#include <unistd.h> +#include <net/if.h> +#include <sys/utsname.h> + +#include <linux/btf.h> +#include <linux/filter.h> +#include <linux/kernel.h> + +#include "bpf.h" +#include "libbpf.h" +#include "libbpf_internal.h" + +static bool grep(const char *buffer, const char *pattern) +{ + return !!strstr(buffer, pattern); +} + +static int get_vendor_id(int ifindex) +{ + char ifname[IF_NAMESIZE], path[64], buf[8]; + ssize_t len; + int fd; + + if (!if_indextoname(ifindex, ifname)) + return -1; + + snprintf(path, sizeof(path), "/sys/class/net/%s/device/vendor", ifname); + + fd = open(path, O_RDONLY); + if (fd < 0) + return -1; + + len = read(fd, buf, sizeof(buf)); + close(fd); + if (len < 0) + return -1; + if (len >= (ssize_t)sizeof(buf)) + return -1; + buf[len] = '\0'; + + return strtol(buf, NULL, 0); +} + +static int get_kernel_version(void) +{ + int version, subversion, patchlevel; + struct utsname utsn; + + /* Return 0 on failure, and attempt to probe with empty kversion */ + if (uname(&utsn)) + return 0; + + if (sscanf(utsn.release, "%d.%d.%d", + &version, &subversion, &patchlevel) != 3) + return 0; + + return (version << 16) + (subversion << 8) + patchlevel; +} + +static void +probe_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns, + size_t insns_cnt, char *buf, size_t buf_len, __u32 ifindex) +{ + struct bpf_load_program_attr xattr = {}; + int fd; + + switch (prog_type) { + case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: + xattr.expected_attach_type = BPF_CGROUP_INET4_CONNECT; + break; + case BPF_PROG_TYPE_CGROUP_SOCKOPT: + xattr.expected_attach_type = BPF_CGROUP_GETSOCKOPT; + break; + case BPF_PROG_TYPE_SK_LOOKUP: + xattr.expected_attach_type = BPF_SK_LOOKUP; + break; + case BPF_PROG_TYPE_KPROBE: + xattr.kern_version = get_kernel_version(); + break; + case BPF_PROG_TYPE_UNSPEC: + case BPF_PROG_TYPE_SOCKET_FILTER: + case BPF_PROG_TYPE_SCHED_CLS: + case BPF_PROG_TYPE_SCHED_ACT: + case BPF_PROG_TYPE_TRACEPOINT: + case BPF_PROG_TYPE_XDP: + case BPF_PROG_TYPE_PERF_EVENT: + case BPF_PROG_TYPE_CGROUP_SKB: + case BPF_PROG_TYPE_CGROUP_SOCK: + case BPF_PROG_TYPE_LWT_IN: + case BPF_PROG_TYPE_LWT_OUT: + case BPF_PROG_TYPE_LWT_XMIT: + case BPF_PROG_TYPE_SOCK_OPS: + case BPF_PROG_TYPE_SK_SKB: + case BPF_PROG_TYPE_CGROUP_DEVICE: + case BPF_PROG_TYPE_SK_MSG: + case BPF_PROG_TYPE_RAW_TRACEPOINT: + case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE: + case BPF_PROG_TYPE_LWT_SEG6LOCAL: + case BPF_PROG_TYPE_LIRC_MODE2: + case BPF_PROG_TYPE_SK_REUSEPORT: + case BPF_PROG_TYPE_FLOW_DISSECTOR: + case BPF_PROG_TYPE_CGROUP_SYSCTL: + case BPF_PROG_TYPE_TRACING: + case BPF_PROG_TYPE_STRUCT_OPS: + case BPF_PROG_TYPE_EXT: + case BPF_PROG_TYPE_LSM: + default: + break; + } + + xattr.prog_type = prog_type; + xattr.insns = insns; + xattr.insns_cnt = insns_cnt; + xattr.license = "GPL"; + xattr.prog_ifindex = ifindex; + + fd = bpf_load_program_xattr(&xattr, buf, buf_len); + if (fd >= 0) + close(fd); +} + +bool bpf_probe_prog_type(enum bpf_prog_type prog_type, __u32 ifindex) +{ + struct bpf_insn insns[2] = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN() + }; + + if (ifindex && prog_type == BPF_PROG_TYPE_SCHED_CLS) + /* nfp returns -EINVAL on exit(0) with TC offload */ + insns[0].imm = 2; + + errno = 0; + probe_load(prog_type, insns, ARRAY_SIZE(insns), NULL, 0, ifindex); + + return errno != EINVAL && errno != EOPNOTSUPP; +} + +int libbpf__load_raw_btf(const char *raw_types, size_t types_len, + const char *str_sec, size_t str_len) +{ + struct btf_header hdr = { + .magic = BTF_MAGIC, + .version = BTF_VERSION, + .hdr_len = sizeof(struct btf_header), + .type_len = types_len, + .str_off = types_len, + .str_len = str_len, + }; + int btf_fd, btf_len; + __u8 *raw_btf; + + btf_len = hdr.hdr_len + hdr.type_len + hdr.str_len; + raw_btf = malloc(btf_len); + if (!raw_btf) + return -ENOMEM; + + memcpy(raw_btf, &hdr, sizeof(hdr)); + memcpy(raw_btf + hdr.hdr_len, raw_types, hdr.type_len); + memcpy(raw_btf + hdr.hdr_len + hdr.type_len, str_sec, hdr.str_len); + + btf_fd = bpf_load_btf(raw_btf, btf_len, NULL, 0, false); + + free(raw_btf); + return btf_fd; +} + +static int load_local_storage_btf(void) +{ + const char strs[] = "\0bpf_spin_lock\0val\0cnt\0l"; + /* struct bpf_spin_lock { + * int val; + * }; + * struct val { + * int cnt; + * struct bpf_spin_lock l; + * }; + */ + __u32 types[] = { + /* int */ + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + /* struct bpf_spin_lock */ /* [2] */ + BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4), + BTF_MEMBER_ENC(15, 1, 0), /* int val; */ + /* struct val */ /* [3] */ + BTF_TYPE_ENC(15, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 2), 8), + BTF_MEMBER_ENC(19, 1, 0), /* int cnt; */ + BTF_MEMBER_ENC(23, 2, 32),/* struct bpf_spin_lock l; */ + }; + + return libbpf__load_raw_btf((char *)types, sizeof(types), + strs, sizeof(strs)); +} + +bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex) +{ + int key_size, value_size, max_entries, map_flags; + __u32 btf_key_type_id = 0, btf_value_type_id = 0; + struct bpf_create_map_attr attr = {}; + int fd = -1, btf_fd = -1, fd_inner; + + key_size = sizeof(__u32); + value_size = sizeof(__u32); + max_entries = 1; + map_flags = 0; + + switch (map_type) { + case BPF_MAP_TYPE_STACK_TRACE: + value_size = sizeof(__u64); + break; + case BPF_MAP_TYPE_LPM_TRIE: + key_size = sizeof(__u64); + value_size = sizeof(__u64); + map_flags = BPF_F_NO_PREALLOC; + break; + case BPF_MAP_TYPE_CGROUP_STORAGE: + case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE: + key_size = sizeof(struct bpf_cgroup_storage_key); + value_size = sizeof(__u64); + max_entries = 0; + break; + case BPF_MAP_TYPE_QUEUE: + case BPF_MAP_TYPE_STACK: + key_size = 0; + break; + case BPF_MAP_TYPE_SK_STORAGE: + case BPF_MAP_TYPE_INODE_STORAGE: + btf_key_type_id = 1; + btf_value_type_id = 3; + value_size = 8; + max_entries = 0; + map_flags = BPF_F_NO_PREALLOC; + btf_fd = load_local_storage_btf(); + if (btf_fd < 0) + return false; + break; + case BPF_MAP_TYPE_RINGBUF: + key_size = 0; + value_size = 0; + max_entries = sysconf(_SC_PAGE_SIZE); + break; + case BPF_MAP_TYPE_UNSPEC: + case BPF_MAP_TYPE_HASH: + case BPF_MAP_TYPE_ARRAY: + case BPF_MAP_TYPE_PROG_ARRAY: + case BPF_MAP_TYPE_PERF_EVENT_ARRAY: + case BPF_MAP_TYPE_PERCPU_HASH: + case BPF_MAP_TYPE_PERCPU_ARRAY: + case BPF_MAP_TYPE_CGROUP_ARRAY: + case BPF_MAP_TYPE_LRU_HASH: + case BPF_MAP_TYPE_LRU_PERCPU_HASH: + case BPF_MAP_TYPE_ARRAY_OF_MAPS: + case BPF_MAP_TYPE_HASH_OF_MAPS: + case BPF_MAP_TYPE_DEVMAP: + case BPF_MAP_TYPE_DEVMAP_HASH: + case BPF_MAP_TYPE_SOCKMAP: + case BPF_MAP_TYPE_CPUMAP: + case BPF_MAP_TYPE_XSKMAP: + case BPF_MAP_TYPE_SOCKHASH: + case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY: + case BPF_MAP_TYPE_STRUCT_OPS: + default: + break; + } + + if (map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS || + map_type == BPF_MAP_TYPE_HASH_OF_MAPS) { + /* TODO: probe for device, once libbpf has a function to create + * map-in-map for offload + */ + if (ifindex) + return false; + + fd_inner = bpf_create_map(BPF_MAP_TYPE_HASH, + sizeof(__u32), sizeof(__u32), 1, 0); + if (fd_inner < 0) + return false; + fd = bpf_create_map_in_map(map_type, NULL, sizeof(__u32), + fd_inner, 1, 0); + close(fd_inner); + } else { + /* Note: No other restriction on map type probes for offload */ + attr.map_type = map_type; + attr.key_size = key_size; + attr.value_size = value_size; + attr.max_entries = max_entries; + attr.map_flags = map_flags; + attr.map_ifindex = ifindex; + if (btf_fd >= 0) { + attr.btf_fd = btf_fd; + attr.btf_key_type_id = btf_key_type_id; + attr.btf_value_type_id = btf_value_type_id; + } + + fd = bpf_create_map_xattr(&attr); + } + if (fd >= 0) + close(fd); + if (btf_fd >= 0) + close(btf_fd); + + return fd >= 0; +} + +bool bpf_probe_helper(enum bpf_func_id id, enum bpf_prog_type prog_type, + __u32 ifindex) +{ + struct bpf_insn insns[2] = { + BPF_EMIT_CALL(id), + BPF_EXIT_INSN() + }; + char buf[4096] = {}; + bool res; + + probe_load(prog_type, insns, ARRAY_SIZE(insns), buf, sizeof(buf), + ifindex); + res = !grep(buf, "invalid func ") && !grep(buf, "unknown func "); + + if (ifindex) { + switch (get_vendor_id(ifindex)) { + case 0x19ee: /* Netronome specific */ + res = res && !grep(buf, "not supported by FW") && + !grep(buf, "unsupported function id"); + break; + default: + break; + } + } + + return res; +} + +/* + * Probe for availability of kernel commit (5.3): + * + * c04c0d2b968a ("bpf: increase complexity limit and maximum program size") + */ +bool bpf_probe_large_insn_limit(__u32 ifindex) +{ + struct bpf_insn insns[BPF_MAXINSNS + 1]; + int i; + + for (i = 0; i < BPF_MAXINSNS; i++) + insns[i] = BPF_MOV64_IMM(BPF_REG_0, 1); + insns[BPF_MAXINSNS] = BPF_EXIT_INSN(); + + errno = 0; + probe_load(BPF_PROG_TYPE_SCHED_CLS, insns, ARRAY_SIZE(insns), NULL, 0, + ifindex); + + return errno != E2BIG && errno != EINVAL; +} diff --git a/tools/lib/bpf/libbpf_util.h b/tools/lib/bpf/libbpf_util.h new file mode 100644 index 000000000..59c779c57 --- /dev/null +++ b/tools/lib/bpf/libbpf_util.h @@ -0,0 +1,47 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ +/* Copyright (c) 2019 Facebook */ + +#ifndef __LIBBPF_LIBBPF_UTIL_H +#define __LIBBPF_LIBBPF_UTIL_H + +#include <stdbool.h> + +#ifdef __cplusplus +extern "C" { +#endif + +/* Use these barrier functions instead of smp_[rw]mb() when they are + * used in a libbpf header file. That way they can be built into the + * application that uses libbpf. + */ +#if defined(__i386__) || defined(__x86_64__) +# define libbpf_smp_rmb() asm volatile("" : : : "memory") +# define libbpf_smp_wmb() asm volatile("" : : : "memory") +# define libbpf_smp_mb() \ + asm volatile("lock; addl $0,-4(%%rsp)" : : : "memory", "cc") +/* Hinders stores to be observed before older loads. */ +# define libbpf_smp_rwmb() asm volatile("" : : : "memory") +#elif defined(__aarch64__) +# define libbpf_smp_rmb() asm volatile("dmb ishld" : : : "memory") +# define libbpf_smp_wmb() asm volatile("dmb ishst" : : : "memory") +# define libbpf_smp_mb() asm volatile("dmb ish" : : : "memory") +# define libbpf_smp_rwmb() libbpf_smp_mb() +#elif defined(__arm__) +/* These are only valid for armv7 and above */ +# define libbpf_smp_rmb() asm volatile("dmb ish" : : : "memory") +# define libbpf_smp_wmb() asm volatile("dmb ishst" : : : "memory") +# define libbpf_smp_mb() asm volatile("dmb ish" : : : "memory") +# define libbpf_smp_rwmb() libbpf_smp_mb() +#else +/* Architecture missing native barrier functions. */ +# define libbpf_smp_rmb() __sync_synchronize() +# define libbpf_smp_wmb() __sync_synchronize() +# define libbpf_smp_mb() __sync_synchronize() +# define libbpf_smp_rwmb() __sync_synchronize() +#endif + +#ifdef __cplusplus +} /* extern "C" */ +#endif + +#endif diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c new file mode 100644 index 000000000..d2cb28e9e --- /dev/null +++ b/tools/lib/bpf/netlink.c @@ -0,0 +1,372 @@ +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) +/* Copyright (c) 2018 Facebook */ + +#include <stdlib.h> +#include <memory.h> +#include <unistd.h> +#include <linux/bpf.h> +#include <linux/rtnetlink.h> +#include <sys/socket.h> +#include <errno.h> +#include <time.h> + +#include "bpf.h" +#include "libbpf.h" +#include "libbpf_internal.h" +#include "nlattr.h" + +#ifndef SOL_NETLINK +#define SOL_NETLINK 270 +#endif + +typedef int (*libbpf_dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb); + +typedef int (*__dump_nlmsg_t)(struct nlmsghdr *nlmsg, libbpf_dump_nlmsg_t, + void *cookie); + +struct xdp_id_md { + int ifindex; + __u32 flags; + struct xdp_link_info info; +}; + +static int libbpf_netlink_open(__u32 *nl_pid) +{ + struct sockaddr_nl sa; + socklen_t addrlen; + int one = 1, ret; + int sock; + + memset(&sa, 0, sizeof(sa)); + sa.nl_family = AF_NETLINK; + + sock = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_ROUTE); + if (sock < 0) + return -errno; + + if (setsockopt(sock, SOL_NETLINK, NETLINK_EXT_ACK, + &one, sizeof(one)) < 0) { + pr_warn("Netlink error reporting not supported\n"); + } + + if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) { + ret = -errno; + goto cleanup; + } + + addrlen = sizeof(sa); + if (getsockname(sock, (struct sockaddr *)&sa, &addrlen) < 0) { + ret = -errno; + goto cleanup; + } + + if (addrlen != sizeof(sa)) { + ret = -LIBBPF_ERRNO__INTERNAL; + goto cleanup; + } + + *nl_pid = sa.nl_pid; + return sock; + +cleanup: + close(sock); + return ret; +} + +static int bpf_netlink_recv(int sock, __u32 nl_pid, int seq, + __dump_nlmsg_t _fn, libbpf_dump_nlmsg_t fn, + void *cookie) +{ + bool multipart = true; + struct nlmsgerr *err; + struct nlmsghdr *nh; + char buf[4096]; + int len, ret; + + while (multipart) { + multipart = false; + len = recv(sock, buf, sizeof(buf), 0); + if (len < 0) { + ret = -errno; + goto done; + } + + if (len == 0) + break; + + for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len); + nh = NLMSG_NEXT(nh, len)) { + if (nh->nlmsg_pid != nl_pid) { + ret = -LIBBPF_ERRNO__WRNGPID; + goto done; + } + if (nh->nlmsg_seq != seq) { + ret = -LIBBPF_ERRNO__INVSEQ; + goto done; + } + if (nh->nlmsg_flags & NLM_F_MULTI) + multipart = true; + switch (nh->nlmsg_type) { + case NLMSG_ERROR: + err = (struct nlmsgerr *)NLMSG_DATA(nh); + if (!err->error) + continue; + ret = err->error; + libbpf_nla_dump_errormsg(nh); + goto done; + case NLMSG_DONE: + return 0; + default: + break; + } + if (_fn) { + ret = _fn(nh, fn, cookie); + if (ret) + return ret; + } + } + } + ret = 0; +done: + return ret; +} + +static int __bpf_set_link_xdp_fd_replace(int ifindex, int fd, int old_fd, + __u32 flags) +{ + int sock, seq = 0, ret; + struct nlattr *nla, *nla_xdp; + struct { + struct nlmsghdr nh; + struct ifinfomsg ifinfo; + char attrbuf[64]; + } req; + __u32 nl_pid = 0; + + sock = libbpf_netlink_open(&nl_pid); + if (sock < 0) + return sock; + + memset(&req, 0, sizeof(req)); + req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)); + req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK; + req.nh.nlmsg_type = RTM_SETLINK; + req.nh.nlmsg_pid = 0; + req.nh.nlmsg_seq = ++seq; + req.ifinfo.ifi_family = AF_UNSPEC; + req.ifinfo.ifi_index = ifindex; + + /* started nested attribute for XDP */ + nla = (struct nlattr *)(((char *)&req) + + NLMSG_ALIGN(req.nh.nlmsg_len)); + nla->nla_type = NLA_F_NESTED | IFLA_XDP; + nla->nla_len = NLA_HDRLEN; + + /* add XDP fd */ + nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len); + nla_xdp->nla_type = IFLA_XDP_FD; + nla_xdp->nla_len = NLA_HDRLEN + sizeof(int); + memcpy((char *)nla_xdp + NLA_HDRLEN, &fd, sizeof(fd)); + nla->nla_len += nla_xdp->nla_len; + + /* if user passed in any flags, add those too */ + if (flags) { + nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len); + nla_xdp->nla_type = IFLA_XDP_FLAGS; + nla_xdp->nla_len = NLA_HDRLEN + sizeof(flags); + memcpy((char *)nla_xdp + NLA_HDRLEN, &flags, sizeof(flags)); + nla->nla_len += nla_xdp->nla_len; + } + + if (flags & XDP_FLAGS_REPLACE) { + nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len); + nla_xdp->nla_type = IFLA_XDP_EXPECTED_FD; + nla_xdp->nla_len = NLA_HDRLEN + sizeof(old_fd); + memcpy((char *)nla_xdp + NLA_HDRLEN, &old_fd, sizeof(old_fd)); + nla->nla_len += nla_xdp->nla_len; + } + + req.nh.nlmsg_len += NLA_ALIGN(nla->nla_len); + + if (send(sock, &req, req.nh.nlmsg_len, 0) < 0) { + ret = -errno; + goto cleanup; + } + ret = bpf_netlink_recv(sock, nl_pid, seq, NULL, NULL, NULL); + +cleanup: + close(sock); + return ret; +} + +int bpf_set_link_xdp_fd_opts(int ifindex, int fd, __u32 flags, + const struct bpf_xdp_set_link_opts *opts) +{ + int old_fd = -1; + + if (!OPTS_VALID(opts, bpf_xdp_set_link_opts)) + return -EINVAL; + + if (OPTS_HAS(opts, old_fd)) { + old_fd = OPTS_GET(opts, old_fd, -1); + flags |= XDP_FLAGS_REPLACE; + } + + return __bpf_set_link_xdp_fd_replace(ifindex, fd, + old_fd, + flags); +} + +int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags) +{ + return __bpf_set_link_xdp_fd_replace(ifindex, fd, 0, flags); +} + +static int __dump_link_nlmsg(struct nlmsghdr *nlh, + libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie) +{ + struct nlattr *tb[IFLA_MAX + 1], *attr; + struct ifinfomsg *ifi = NLMSG_DATA(nlh); + int len; + + len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*ifi)); + attr = (struct nlattr *) ((void *) ifi + NLMSG_ALIGN(sizeof(*ifi))); + if (libbpf_nla_parse(tb, IFLA_MAX, attr, len, NULL) != 0) + return -LIBBPF_ERRNO__NLPARSE; + + return dump_link_nlmsg(cookie, ifi, tb); +} + +static int get_xdp_info(void *cookie, void *msg, struct nlattr **tb) +{ + struct nlattr *xdp_tb[IFLA_XDP_MAX + 1]; + struct xdp_id_md *xdp_id = cookie; + struct ifinfomsg *ifinfo = msg; + int ret; + + if (xdp_id->ifindex && xdp_id->ifindex != ifinfo->ifi_index) + return 0; + + if (!tb[IFLA_XDP]) + return 0; + + ret = libbpf_nla_parse_nested(xdp_tb, IFLA_XDP_MAX, tb[IFLA_XDP], NULL); + if (ret) + return ret; + + if (!xdp_tb[IFLA_XDP_ATTACHED]) + return 0; + + xdp_id->info.attach_mode = libbpf_nla_getattr_u8( + xdp_tb[IFLA_XDP_ATTACHED]); + + if (xdp_id->info.attach_mode == XDP_ATTACHED_NONE) + return 0; + + if (xdp_tb[IFLA_XDP_PROG_ID]) + xdp_id->info.prog_id = libbpf_nla_getattr_u32( + xdp_tb[IFLA_XDP_PROG_ID]); + + if (xdp_tb[IFLA_XDP_SKB_PROG_ID]) + xdp_id->info.skb_prog_id = libbpf_nla_getattr_u32( + xdp_tb[IFLA_XDP_SKB_PROG_ID]); + + if (xdp_tb[IFLA_XDP_DRV_PROG_ID]) + xdp_id->info.drv_prog_id = libbpf_nla_getattr_u32( + xdp_tb[IFLA_XDP_DRV_PROG_ID]); + + if (xdp_tb[IFLA_XDP_HW_PROG_ID]) + xdp_id->info.hw_prog_id = libbpf_nla_getattr_u32( + xdp_tb[IFLA_XDP_HW_PROG_ID]); + + return 0; +} + +static int libbpf_nl_get_link(int sock, unsigned int nl_pid, + libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie); + +int bpf_get_link_xdp_info(int ifindex, struct xdp_link_info *info, + size_t info_size, __u32 flags) +{ + struct xdp_id_md xdp_id = {}; + int sock, ret; + __u32 nl_pid = 0; + __u32 mask; + + if (flags & ~XDP_FLAGS_MASK || !info_size) + return -EINVAL; + + /* Check whether the single {HW,DRV,SKB} mode is set */ + flags &= (XDP_FLAGS_SKB_MODE | XDP_FLAGS_DRV_MODE | XDP_FLAGS_HW_MODE); + mask = flags - 1; + if (flags && flags & mask) + return -EINVAL; + + sock = libbpf_netlink_open(&nl_pid); + if (sock < 0) + return sock; + + xdp_id.ifindex = ifindex; + xdp_id.flags = flags; + + ret = libbpf_nl_get_link(sock, nl_pid, get_xdp_info, &xdp_id); + if (!ret) { + size_t sz = min(info_size, sizeof(xdp_id.info)); + + memcpy(info, &xdp_id.info, sz); + memset((void *) info + sz, 0, info_size - sz); + } + + close(sock); + return ret; +} + +static __u32 get_xdp_id(struct xdp_link_info *info, __u32 flags) +{ + flags &= XDP_FLAGS_MODES; + + if (info->attach_mode != XDP_ATTACHED_MULTI && !flags) + return info->prog_id; + if (flags & XDP_FLAGS_DRV_MODE) + return info->drv_prog_id; + if (flags & XDP_FLAGS_HW_MODE) + return info->hw_prog_id; + if (flags & XDP_FLAGS_SKB_MODE) + return info->skb_prog_id; + + return 0; +} + +int bpf_get_link_xdp_id(int ifindex, __u32 *prog_id, __u32 flags) +{ + struct xdp_link_info info; + int ret; + + ret = bpf_get_link_xdp_info(ifindex, &info, sizeof(info), flags); + if (!ret) + *prog_id = get_xdp_id(&info, flags); + + return ret; +} + +int libbpf_nl_get_link(int sock, unsigned int nl_pid, + libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie) +{ + struct { + struct nlmsghdr nlh; + struct ifinfomsg ifm; + } req = { + .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)), + .nlh.nlmsg_type = RTM_GETLINK, + .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, + .ifm.ifi_family = AF_PACKET, + }; + int seq = time(NULL); + + req.nlh.nlmsg_seq = seq; + if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0) + return -errno; + + return bpf_netlink_recv(sock, nl_pid, seq, __dump_link_nlmsg, + dump_link_nlmsg, cookie); +} diff --git a/tools/lib/bpf/nlattr.c b/tools/lib/bpf/nlattr.c new file mode 100644 index 000000000..1a04299a2 --- /dev/null +++ b/tools/lib/bpf/nlattr.c @@ -0,0 +1,195 @@ +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) + +/* + * NETLINK Netlink attributes + * + * Copyright (c) 2003-2013 Thomas Graf <tgraf@suug.ch> + */ + +#include <errno.h> +#include <string.h> +#include <stdio.h> +#include <linux/rtnetlink.h> +#include "nlattr.h" +#include "libbpf_internal.h" + +static uint16_t nla_attr_minlen[LIBBPF_NLA_TYPE_MAX+1] = { + [LIBBPF_NLA_U8] = sizeof(uint8_t), + [LIBBPF_NLA_U16] = sizeof(uint16_t), + [LIBBPF_NLA_U32] = sizeof(uint32_t), + [LIBBPF_NLA_U64] = sizeof(uint64_t), + [LIBBPF_NLA_STRING] = 1, + [LIBBPF_NLA_FLAG] = 0, +}; + +static struct nlattr *nla_next(const struct nlattr *nla, int *remaining) +{ + int totlen = NLA_ALIGN(nla->nla_len); + + *remaining -= totlen; + return (struct nlattr *) ((char *) nla + totlen); +} + +static int nla_ok(const struct nlattr *nla, int remaining) +{ + return remaining >= sizeof(*nla) && + nla->nla_len >= sizeof(*nla) && + nla->nla_len <= remaining; +} + +static int nla_type(const struct nlattr *nla) +{ + return nla->nla_type & NLA_TYPE_MASK; +} + +static int validate_nla(struct nlattr *nla, int maxtype, + struct libbpf_nla_policy *policy) +{ + struct libbpf_nla_policy *pt; + unsigned int minlen = 0; + int type = nla_type(nla); + + if (type < 0 || type > maxtype) + return 0; + + pt = &policy[type]; + + if (pt->type > LIBBPF_NLA_TYPE_MAX) + return 0; + + if (pt->minlen) + minlen = pt->minlen; + else if (pt->type != LIBBPF_NLA_UNSPEC) + minlen = nla_attr_minlen[pt->type]; + + if (libbpf_nla_len(nla) < minlen) + return -1; + + if (pt->maxlen && libbpf_nla_len(nla) > pt->maxlen) + return -1; + + if (pt->type == LIBBPF_NLA_STRING) { + char *data = libbpf_nla_data(nla); + + if (data[libbpf_nla_len(nla) - 1] != '\0') + return -1; + } + + return 0; +} + +static inline int nlmsg_len(const struct nlmsghdr *nlh) +{ + return nlh->nlmsg_len - NLMSG_HDRLEN; +} + +/** + * Create attribute index based on a stream of attributes. + * @arg tb Index array to be filled (maxtype+1 elements). + * @arg maxtype Maximum attribute type expected and accepted. + * @arg head Head of attribute stream. + * @arg len Length of attribute stream. + * @arg policy Attribute validation policy. + * + * Iterates over the stream of attributes and stores a pointer to each + * attribute in the index array using the attribute type as index to + * the array. Attribute with a type greater than the maximum type + * specified will be silently ignored in order to maintain backwards + * compatibility. If \a policy is not NULL, the attribute will be + * validated using the specified policy. + * + * @see nla_validate + * @return 0 on success or a negative error code. + */ +int libbpf_nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, + int len, struct libbpf_nla_policy *policy) +{ + struct nlattr *nla; + int rem, err; + + memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1)); + + libbpf_nla_for_each_attr(nla, head, len, rem) { + int type = nla_type(nla); + + if (type > maxtype) + continue; + + if (policy) { + err = validate_nla(nla, maxtype, policy); + if (err < 0) + goto errout; + } + + if (tb[type]) + pr_warn("Attribute of type %#x found multiple times in message, " + "previous attribute is being ignored.\n", type); + + tb[type] = nla; + } + + err = 0; +errout: + return err; +} + +/** + * Create attribute index based on nested attribute + * @arg tb Index array to be filled (maxtype+1 elements). + * @arg maxtype Maximum attribute type expected and accepted. + * @arg nla Nested Attribute. + * @arg policy Attribute validation policy. + * + * Feeds the stream of attributes nested into the specified attribute + * to libbpf_nla_parse(). + * + * @see libbpf_nla_parse + * @return 0 on success or a negative error code. + */ +int libbpf_nla_parse_nested(struct nlattr *tb[], int maxtype, + struct nlattr *nla, + struct libbpf_nla_policy *policy) +{ + return libbpf_nla_parse(tb, maxtype, libbpf_nla_data(nla), + libbpf_nla_len(nla), policy); +} + +/* dump netlink extended ack error message */ +int libbpf_nla_dump_errormsg(struct nlmsghdr *nlh) +{ + struct libbpf_nla_policy extack_policy[NLMSGERR_ATTR_MAX + 1] = { + [NLMSGERR_ATTR_MSG] = { .type = LIBBPF_NLA_STRING }, + [NLMSGERR_ATTR_OFFS] = { .type = LIBBPF_NLA_U32 }, + }; + struct nlattr *tb[NLMSGERR_ATTR_MAX + 1], *attr; + struct nlmsgerr *err; + char *errmsg = NULL; + int hlen, alen; + + /* no TLVs, nothing to do here */ + if (!(nlh->nlmsg_flags & NLM_F_ACK_TLVS)) + return 0; + + err = (struct nlmsgerr *)NLMSG_DATA(nlh); + hlen = sizeof(*err); + + /* if NLM_F_CAPPED is set then the inner err msg was capped */ + if (!(nlh->nlmsg_flags & NLM_F_CAPPED)) + hlen += nlmsg_len(&err->msg); + + attr = (struct nlattr *) ((void *) err + hlen); + alen = (void *)nlh + nlh->nlmsg_len - (void *)attr; + + if (libbpf_nla_parse(tb, NLMSGERR_ATTR_MAX, attr, alen, + extack_policy) != 0) { + pr_warn("Failed to parse extended error attributes\n"); + return 0; + } + + if (tb[NLMSGERR_ATTR_MSG]) + errmsg = (char *) libbpf_nla_data(tb[NLMSGERR_ATTR_MSG]); + + pr_warn("Kernel error message: %s\n", errmsg); + + return 0; +} diff --git a/tools/lib/bpf/nlattr.h b/tools/lib/bpf/nlattr.h new file mode 100644 index 000000000..6cc3ac916 --- /dev/null +++ b/tools/lib/bpf/nlattr.h @@ -0,0 +1,106 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ + +/* + * NETLINK Netlink attributes + * + * Copyright (c) 2003-2013 Thomas Graf <tgraf@suug.ch> + */ + +#ifndef __LIBBPF_NLATTR_H +#define __LIBBPF_NLATTR_H + +#include <stdint.h> +#include <linux/netlink.h> +/* avoid multiple definition of netlink features */ +#define __LINUX_NETLINK_H + +/** + * Standard attribute types to specify validation policy + */ +enum { + LIBBPF_NLA_UNSPEC, /**< Unspecified type, binary data chunk */ + LIBBPF_NLA_U8, /**< 8 bit integer */ + LIBBPF_NLA_U16, /**< 16 bit integer */ + LIBBPF_NLA_U32, /**< 32 bit integer */ + LIBBPF_NLA_U64, /**< 64 bit integer */ + LIBBPF_NLA_STRING, /**< NUL terminated character string */ + LIBBPF_NLA_FLAG, /**< Flag */ + LIBBPF_NLA_MSECS, /**< Micro seconds (64bit) */ + LIBBPF_NLA_NESTED, /**< Nested attributes */ + __LIBBPF_NLA_TYPE_MAX, +}; + +#define LIBBPF_NLA_TYPE_MAX (__LIBBPF_NLA_TYPE_MAX - 1) + +/** + * @ingroup attr + * Attribute validation policy. + * + * See section @core_doc{core_attr_parse,Attribute Parsing} for more details. + */ +struct libbpf_nla_policy { + /** Type of attribute or LIBBPF_NLA_UNSPEC */ + uint16_t type; + + /** Minimal length of payload required */ + uint16_t minlen; + + /** Maximal length of payload allowed */ + uint16_t maxlen; +}; + +/** + * @ingroup attr + * Iterate over a stream of attributes + * @arg pos loop counter, set to current attribute + * @arg head head of attribute stream + * @arg len length of attribute stream + * @arg rem initialized to len, holds bytes currently remaining in stream + */ +#define libbpf_nla_for_each_attr(pos, head, len, rem) \ + for (pos = head, rem = len; \ + nla_ok(pos, rem); \ + pos = nla_next(pos, &(rem))) + +/** + * libbpf_nla_data - head of payload + * @nla: netlink attribute + */ +static inline void *libbpf_nla_data(const struct nlattr *nla) +{ + return (char *) nla + NLA_HDRLEN; +} + +static inline uint8_t libbpf_nla_getattr_u8(const struct nlattr *nla) +{ + return *(uint8_t *)libbpf_nla_data(nla); +} + +static inline uint32_t libbpf_nla_getattr_u32(const struct nlattr *nla) +{ + return *(uint32_t *)libbpf_nla_data(nla); +} + +static inline const char *libbpf_nla_getattr_str(const struct nlattr *nla) +{ + return (const char *)libbpf_nla_data(nla); +} + +/** + * libbpf_nla_len - length of payload + * @nla: netlink attribute + */ +static inline int libbpf_nla_len(const struct nlattr *nla) +{ + return nla->nla_len - NLA_HDRLEN; +} + +int libbpf_nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, + int len, struct libbpf_nla_policy *policy); +int libbpf_nla_parse_nested(struct nlattr *tb[], int maxtype, + struct nlattr *nla, + struct libbpf_nla_policy *policy); + +int libbpf_nla_dump_errormsg(struct nlmsghdr *nlh); + +#endif /* __LIBBPF_NLATTR_H */ diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c new file mode 100644 index 000000000..5e242be45 --- /dev/null +++ b/tools/lib/bpf/ringbuf.c @@ -0,0 +1,300 @@ +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) +/* + * Ring buffer operations. + * + * Copyright (C) 2020 Facebook, Inc. + */ +#ifndef _GNU_SOURCE +#define _GNU_SOURCE +#endif +#include <stdlib.h> +#include <stdio.h> +#include <errno.h> +#include <unistd.h> +#include <linux/err.h> +#include <linux/bpf.h> +#include <asm/barrier.h> +#include <sys/mman.h> +#include <sys/epoll.h> + +#include "libbpf.h" +#include "libbpf_internal.h" +#include "bpf.h" + +struct ring { + ring_buffer_sample_fn sample_cb; + void *ctx; + void *data; + unsigned long *consumer_pos; + unsigned long *producer_pos; + unsigned long mask; + int map_fd; +}; + +struct ring_buffer { + struct epoll_event *events; + struct ring *rings; + size_t page_size; + int epoll_fd; + int ring_cnt; +}; + +static void ringbuf_unmap_ring(struct ring_buffer *rb, struct ring *r) +{ + if (r->consumer_pos) { + munmap(r->consumer_pos, rb->page_size); + r->consumer_pos = NULL; + } + if (r->producer_pos) { + munmap(r->producer_pos, rb->page_size + 2 * (r->mask + 1)); + r->producer_pos = NULL; + } +} + +/* Add extra RINGBUF maps to this ring buffer manager */ +int ring_buffer__add(struct ring_buffer *rb, int map_fd, + ring_buffer_sample_fn sample_cb, void *ctx) +{ + struct bpf_map_info info; + __u32 len = sizeof(info); + struct epoll_event *e; + struct ring *r; + __u64 mmap_sz; + void *tmp; + int err; + + memset(&info, 0, sizeof(info)); + + err = bpf_obj_get_info_by_fd(map_fd, &info, &len); + if (err) { + err = -errno; + pr_warn("ringbuf: failed to get map info for fd=%d: %d\n", + map_fd, err); + return err; + } + + if (info.type != BPF_MAP_TYPE_RINGBUF) { + pr_warn("ringbuf: map fd=%d is not BPF_MAP_TYPE_RINGBUF\n", + map_fd); + return -EINVAL; + } + + tmp = libbpf_reallocarray(rb->rings, rb->ring_cnt + 1, sizeof(*rb->rings)); + if (!tmp) + return -ENOMEM; + rb->rings = tmp; + + tmp = libbpf_reallocarray(rb->events, rb->ring_cnt + 1, sizeof(*rb->events)); + if (!tmp) + return -ENOMEM; + rb->events = tmp; + + r = &rb->rings[rb->ring_cnt]; + memset(r, 0, sizeof(*r)); + + r->map_fd = map_fd; + r->sample_cb = sample_cb; + r->ctx = ctx; + r->mask = info.max_entries - 1; + + /* Map writable consumer page */ + tmp = mmap(NULL, rb->page_size, PROT_READ | PROT_WRITE, MAP_SHARED, map_fd, 0); + if (tmp == MAP_FAILED) { + err = -errno; + pr_warn("ringbuf: failed to mmap consumer page for map fd=%d: %d\n", + map_fd, err); + return err; + } + r->consumer_pos = tmp; + + /* Map read-only producer page and data pages. We map twice as big + * data size to allow simple reading of samples that wrap around the + * end of a ring buffer. See kernel implementation for details. + * */ + mmap_sz = rb->page_size + 2 * (__u64)info.max_entries; + if (mmap_sz != (__u64)(size_t)mmap_sz) { + pr_warn("ringbuf: ring buffer size (%u) is too big\n", info.max_entries); + return -E2BIG; + } + tmp = mmap(NULL, (size_t)mmap_sz, PROT_READ, MAP_SHARED, map_fd, rb->page_size); + if (tmp == MAP_FAILED) { + err = -errno; + ringbuf_unmap_ring(rb, r); + pr_warn("ringbuf: failed to mmap data pages for map fd=%d: %d\n", + map_fd, err); + return err; + } + r->producer_pos = tmp; + r->data = tmp + rb->page_size; + + e = &rb->events[rb->ring_cnt]; + memset(e, 0, sizeof(*e)); + + e->events = EPOLLIN; + e->data.fd = rb->ring_cnt; + if (epoll_ctl(rb->epoll_fd, EPOLL_CTL_ADD, map_fd, e) < 0) { + err = -errno; + ringbuf_unmap_ring(rb, r); + pr_warn("ringbuf: failed to epoll add map fd=%d: %d\n", + map_fd, err); + return err; + } + + rb->ring_cnt++; + return 0; +} + +void ring_buffer__free(struct ring_buffer *rb) +{ + int i; + + if (!rb) + return; + + for (i = 0; i < rb->ring_cnt; ++i) + ringbuf_unmap_ring(rb, &rb->rings[i]); + if (rb->epoll_fd >= 0) + close(rb->epoll_fd); + + free(rb->events); + free(rb->rings); + free(rb); +} + +struct ring_buffer * +ring_buffer__new(int map_fd, ring_buffer_sample_fn sample_cb, void *ctx, + const struct ring_buffer_opts *opts) +{ + struct ring_buffer *rb; + int err; + + if (!OPTS_VALID(opts, ring_buffer_opts)) + return NULL; + + rb = calloc(1, sizeof(*rb)); + if (!rb) + return NULL; + + rb->page_size = getpagesize(); + + rb->epoll_fd = epoll_create1(EPOLL_CLOEXEC); + if (rb->epoll_fd < 0) { + err = -errno; + pr_warn("ringbuf: failed to create epoll instance: %d\n", err); + goto err_out; + } + + err = ring_buffer__add(rb, map_fd, sample_cb, ctx); + if (err) + goto err_out; + + return rb; + +err_out: + ring_buffer__free(rb); + return NULL; +} + +static inline int roundup_len(__u32 len) +{ + /* clear out top 2 bits (discard and busy, if set) */ + len <<= 2; + len >>= 2; + /* add length prefix */ + len += BPF_RINGBUF_HDR_SZ; + /* round up to 8 byte alignment */ + return (len + 7) / 8 * 8; +} + +static int64_t ringbuf_process_ring(struct ring* r) +{ + int *len_ptr, len, err; + /* 64-bit to avoid overflow in case of extreme application behavior */ + int64_t cnt = 0; + unsigned long cons_pos, prod_pos; + bool got_new_data; + void *sample; + + cons_pos = smp_load_acquire(r->consumer_pos); + do { + got_new_data = false; + prod_pos = smp_load_acquire(r->producer_pos); + while (cons_pos < prod_pos) { + len_ptr = r->data + (cons_pos & r->mask); + len = smp_load_acquire(len_ptr); + + /* sample not committed yet, bail out for now */ + if (len & BPF_RINGBUF_BUSY_BIT) + goto done; + + got_new_data = true; + cons_pos += roundup_len(len); + + if ((len & BPF_RINGBUF_DISCARD_BIT) == 0) { + sample = (void *)len_ptr + BPF_RINGBUF_HDR_SZ; + err = r->sample_cb(r->ctx, sample, len); + if (err < 0) { + /* update consumer pos and bail out */ + smp_store_release(r->consumer_pos, + cons_pos); + return err; + } + cnt++; + } + + smp_store_release(r->consumer_pos, cons_pos); + } + } while (got_new_data); +done: + return cnt; +} + +/* Consume available ring buffer(s) data without event polling. + * Returns number of records consumed across all registered ring buffers (or + * INT_MAX, whichever is less), or negative number if any of the callbacks + * return error. + */ +int ring_buffer__consume(struct ring_buffer *rb) +{ + int64_t err, res = 0; + int i; + + for (i = 0; i < rb->ring_cnt; i++) { + struct ring *ring = &rb->rings[i]; + + err = ringbuf_process_ring(ring); + if (err < 0) + return err; + res += err; + } + if (res > INT_MAX) + return INT_MAX; + return res; +} + +/* Poll for available data and consume records, if any are available. + * Returns number of records consumed (or INT_MAX, whichever is less), or + * negative number, if any of the registered callbacks returned error. + */ +int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms) +{ + int i, cnt; + int64_t err, res = 0; + + cnt = epoll_wait(rb->epoll_fd, rb->events, rb->ring_cnt, timeout_ms); + if (cnt < 0) + return -errno; + + for (i = 0; i < cnt; i++) { + __u32 ring_id = rb->events[i].data.fd; + struct ring *ring = &rb->rings[ring_id]; + + err = ringbuf_process_ring(ring); + if (err < 0) + return err; + res += err; + } + if (res > INT_MAX) + return INT_MAX; + return res; +} diff --git a/tools/lib/bpf/str_error.c b/tools/lib/bpf/str_error.c new file mode 100644 index 000000000..146da0197 --- /dev/null +++ b/tools/lib/bpf/str_error.c @@ -0,0 +1,21 @@ +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) +#undef _GNU_SOURCE +#include <string.h> +#include <stdio.h> +#include "str_error.h" + +/* make sure libbpf doesn't use kernel-only integer typedefs */ +#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 + +/* + * Wrapper to allow for building in non-GNU systems such as Alpine Linux's musl + * libc, while checking strerror_r() return to avoid having to check this in + * all places calling it. + */ +char *libbpf_strerror_r(int err, char *dst, int len) +{ + int ret = strerror_r(err < 0 ? -err : err, dst, len); + if (ret) + snprintf(dst, len, "ERROR: strerror_r(%d)=%d", err, ret); + return dst; +} diff --git a/tools/lib/bpf/str_error.h b/tools/lib/bpf/str_error.h new file mode 100644 index 000000000..a139334d5 --- /dev/null +++ b/tools/lib/bpf/str_error.h @@ -0,0 +1,6 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ +#ifndef __LIBBPF_STR_ERROR_H +#define __LIBBPF_STR_ERROR_H + +char *libbpf_strerror_r(int err, char *dst, int len); +#endif /* __LIBBPF_STR_ERROR_H */ diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c new file mode 100644 index 000000000..fa1f8faf7 --- /dev/null +++ b/tools/lib/bpf/xsk.c @@ -0,0 +1,959 @@ +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) + +/* + * AF_XDP user-space access library. + * + * Copyright(c) 2018 - 2019 Intel Corporation. + * + * Author(s): Magnus Karlsson <magnus.karlsson@intel.com> + */ + +#include <errno.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <arpa/inet.h> +#include <asm/barrier.h> +#include <linux/compiler.h> +#include <linux/ethtool.h> +#include <linux/filter.h> +#include <linux/if_ether.h> +#include <linux/if_packet.h> +#include <linux/if_xdp.h> +#include <linux/kernel.h> +#include <linux/list.h> +#include <linux/sockios.h> +#include <net/if.h> +#include <sys/ioctl.h> +#include <sys/mman.h> +#include <sys/socket.h> +#include <sys/types.h> + +#include "bpf.h" +#include "libbpf.h" +#include "libbpf_internal.h" +#include "xsk.h" + +#ifndef SOL_XDP + #define SOL_XDP 283 +#endif + +#ifndef AF_XDP + #define AF_XDP 44 +#endif + +#ifndef PF_XDP + #define PF_XDP AF_XDP +#endif + +struct xsk_umem { + struct xsk_ring_prod *fill_save; + struct xsk_ring_cons *comp_save; + char *umem_area; + struct xsk_umem_config config; + int fd; + int refcount; + struct list_head ctx_list; + bool rx_ring_setup_done; + bool tx_ring_setup_done; +}; + +struct xsk_ctx { + struct xsk_ring_prod *fill; + struct xsk_ring_cons *comp; + __u32 queue_id; + struct xsk_umem *umem; + int refcount; + int ifindex; + struct list_head list; + int prog_fd; + int xsks_map_fd; + char ifname[IFNAMSIZ]; +}; + +struct xsk_socket { + struct xsk_ring_cons *rx; + struct xsk_ring_prod *tx; + __u64 outstanding_tx; + struct xsk_ctx *ctx; + struct xsk_socket_config config; + int fd; +}; + +struct xsk_nl_info { + bool xdp_prog_attached; + int ifindex; + int fd; +}; + +/* Up until and including Linux 5.3 */ +struct xdp_ring_offset_v1 { + __u64 producer; + __u64 consumer; + __u64 desc; +}; + +/* Up until and including Linux 5.3 */ +struct xdp_mmap_offsets_v1 { + struct xdp_ring_offset_v1 rx; + struct xdp_ring_offset_v1 tx; + struct xdp_ring_offset_v1 fr; + struct xdp_ring_offset_v1 cr; +}; + +int xsk_umem__fd(const struct xsk_umem *umem) +{ + return umem ? umem->fd : -EINVAL; +} + +int xsk_socket__fd(const struct xsk_socket *xsk) +{ + return xsk ? xsk->fd : -EINVAL; +} + +static bool xsk_page_aligned(void *buffer) +{ + unsigned long addr = (unsigned long)buffer; + + return !(addr & (getpagesize() - 1)); +} + +static void xsk_set_umem_config(struct xsk_umem_config *cfg, + const struct xsk_umem_config *usr_cfg) +{ + if (!usr_cfg) { + cfg->fill_size = XSK_RING_PROD__DEFAULT_NUM_DESCS; + cfg->comp_size = XSK_RING_CONS__DEFAULT_NUM_DESCS; + cfg->frame_size = XSK_UMEM__DEFAULT_FRAME_SIZE; + cfg->frame_headroom = XSK_UMEM__DEFAULT_FRAME_HEADROOM; + cfg->flags = XSK_UMEM__DEFAULT_FLAGS; + return; + } + + cfg->fill_size = usr_cfg->fill_size; + cfg->comp_size = usr_cfg->comp_size; + cfg->frame_size = usr_cfg->frame_size; + cfg->frame_headroom = usr_cfg->frame_headroom; + cfg->flags = usr_cfg->flags; +} + +static int xsk_set_xdp_socket_config(struct xsk_socket_config *cfg, + const struct xsk_socket_config *usr_cfg) +{ + if (!usr_cfg) { + cfg->rx_size = XSK_RING_CONS__DEFAULT_NUM_DESCS; + cfg->tx_size = XSK_RING_PROD__DEFAULT_NUM_DESCS; + cfg->libbpf_flags = 0; + cfg->xdp_flags = 0; + cfg->bind_flags = 0; + return 0; + } + + if (usr_cfg->libbpf_flags & ~XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD) + return -EINVAL; + + cfg->rx_size = usr_cfg->rx_size; + cfg->tx_size = usr_cfg->tx_size; + cfg->libbpf_flags = usr_cfg->libbpf_flags; + cfg->xdp_flags = usr_cfg->xdp_flags; + cfg->bind_flags = usr_cfg->bind_flags; + + return 0; +} + +static void xsk_mmap_offsets_v1(struct xdp_mmap_offsets *off) +{ + struct xdp_mmap_offsets_v1 off_v1; + + /* getsockopt on a kernel <= 5.3 has no flags fields. + * Copy over the offsets to the correct places in the >=5.4 format + * and put the flags where they would have been on that kernel. + */ + memcpy(&off_v1, off, sizeof(off_v1)); + + off->rx.producer = off_v1.rx.producer; + off->rx.consumer = off_v1.rx.consumer; + off->rx.desc = off_v1.rx.desc; + off->rx.flags = off_v1.rx.consumer + sizeof(__u32); + + off->tx.producer = off_v1.tx.producer; + off->tx.consumer = off_v1.tx.consumer; + off->tx.desc = off_v1.tx.desc; + off->tx.flags = off_v1.tx.consumer + sizeof(__u32); + + off->fr.producer = off_v1.fr.producer; + off->fr.consumer = off_v1.fr.consumer; + off->fr.desc = off_v1.fr.desc; + off->fr.flags = off_v1.fr.consumer + sizeof(__u32); + + off->cr.producer = off_v1.cr.producer; + off->cr.consumer = off_v1.cr.consumer; + off->cr.desc = off_v1.cr.desc; + off->cr.flags = off_v1.cr.consumer + sizeof(__u32); +} + +static int xsk_get_mmap_offsets(int fd, struct xdp_mmap_offsets *off) +{ + socklen_t optlen; + int err; + + optlen = sizeof(*off); + err = getsockopt(fd, SOL_XDP, XDP_MMAP_OFFSETS, off, &optlen); + if (err) + return err; + + if (optlen == sizeof(*off)) + return 0; + + if (optlen == sizeof(struct xdp_mmap_offsets_v1)) { + xsk_mmap_offsets_v1(off); + return 0; + } + + return -EINVAL; +} + +static int xsk_create_umem_rings(struct xsk_umem *umem, int fd, + struct xsk_ring_prod *fill, + struct xsk_ring_cons *comp) +{ + struct xdp_mmap_offsets off; + void *map; + int err; + + err = setsockopt(fd, SOL_XDP, XDP_UMEM_FILL_RING, + &umem->config.fill_size, + sizeof(umem->config.fill_size)); + if (err) + return -errno; + + err = setsockopt(fd, SOL_XDP, XDP_UMEM_COMPLETION_RING, + &umem->config.comp_size, + sizeof(umem->config.comp_size)); + if (err) + return -errno; + + err = xsk_get_mmap_offsets(fd, &off); + if (err) + return -errno; + + map = mmap(NULL, off.fr.desc + umem->config.fill_size * sizeof(__u64), + PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd, + XDP_UMEM_PGOFF_FILL_RING); + if (map == MAP_FAILED) + return -errno; + + fill->mask = umem->config.fill_size - 1; + fill->size = umem->config.fill_size; + fill->producer = map + off.fr.producer; + fill->consumer = map + off.fr.consumer; + fill->flags = map + off.fr.flags; + fill->ring = map + off.fr.desc; + fill->cached_cons = umem->config.fill_size; + + map = mmap(NULL, off.cr.desc + umem->config.comp_size * sizeof(__u64), + PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd, + XDP_UMEM_PGOFF_COMPLETION_RING); + if (map == MAP_FAILED) { + err = -errno; + goto out_mmap; + } + + comp->mask = umem->config.comp_size - 1; + comp->size = umem->config.comp_size; + comp->producer = map + off.cr.producer; + comp->consumer = map + off.cr.consumer; + comp->flags = map + off.cr.flags; + comp->ring = map + off.cr.desc; + + return 0; + +out_mmap: + munmap(map, off.fr.desc + umem->config.fill_size * sizeof(__u64)); + return err; +} + +int xsk_umem__create_v0_0_4(struct xsk_umem **umem_ptr, void *umem_area, + __u64 size, struct xsk_ring_prod *fill, + struct xsk_ring_cons *comp, + const struct xsk_umem_config *usr_config) +{ + struct xdp_umem_reg mr; + struct xsk_umem *umem; + int err; + + if (!umem_area || !umem_ptr || !fill || !comp) + return -EFAULT; + if (!size && !xsk_page_aligned(umem_area)) + return -EINVAL; + + umem = calloc(1, sizeof(*umem)); + if (!umem) + return -ENOMEM; + + umem->fd = socket(AF_XDP, SOCK_RAW, 0); + if (umem->fd < 0) { + err = -errno; + goto out_umem_alloc; + } + + umem->umem_area = umem_area; + INIT_LIST_HEAD(&umem->ctx_list); + xsk_set_umem_config(&umem->config, usr_config); + + memset(&mr, 0, sizeof(mr)); + mr.addr = (uintptr_t)umem_area; + mr.len = size; + mr.chunk_size = umem->config.frame_size; + mr.headroom = umem->config.frame_headroom; + mr.flags = umem->config.flags; + + err = setsockopt(umem->fd, SOL_XDP, XDP_UMEM_REG, &mr, sizeof(mr)); + if (err) { + err = -errno; + goto out_socket; + } + + err = xsk_create_umem_rings(umem, umem->fd, fill, comp); + if (err) + goto out_socket; + + umem->fill_save = fill; + umem->comp_save = comp; + *umem_ptr = umem; + return 0; + +out_socket: + close(umem->fd); +out_umem_alloc: + free(umem); + return err; +} + +struct xsk_umem_config_v1 { + __u32 fill_size; + __u32 comp_size; + __u32 frame_size; + __u32 frame_headroom; +}; + +int xsk_umem__create_v0_0_2(struct xsk_umem **umem_ptr, void *umem_area, + __u64 size, struct xsk_ring_prod *fill, + struct xsk_ring_cons *comp, + const struct xsk_umem_config *usr_config) +{ + struct xsk_umem_config config; + + memcpy(&config, usr_config, sizeof(struct xsk_umem_config_v1)); + config.flags = 0; + + return xsk_umem__create_v0_0_4(umem_ptr, umem_area, size, fill, comp, + &config); +} +COMPAT_VERSION(xsk_umem__create_v0_0_2, xsk_umem__create, LIBBPF_0.0.2) +DEFAULT_VERSION(xsk_umem__create_v0_0_4, xsk_umem__create, LIBBPF_0.0.4) + +static int xsk_load_xdp_prog(struct xsk_socket *xsk) +{ + static const int log_buf_size = 16 * 1024; + struct xsk_ctx *ctx = xsk->ctx; + char log_buf[log_buf_size]; + int err, prog_fd; + + /* This is the C-program: + * SEC("xdp_sock") int xdp_sock_prog(struct xdp_md *ctx) + * { + * int ret, index = ctx->rx_queue_index; + * + * // A set entry here means that the correspnding queue_id + * // has an active AF_XDP socket bound to it. + * ret = bpf_redirect_map(&xsks_map, index, XDP_PASS); + * if (ret > 0) + * return ret; + * + * // Fallback for pre-5.3 kernels, not supporting default + * // action in the flags parameter. + * if (bpf_map_lookup_elem(&xsks_map, &index)) + * return bpf_redirect_map(&xsks_map, index, 0); + * return XDP_PASS; + * } + */ + struct bpf_insn prog[] = { + /* r2 = *(u32 *)(r1 + 16) */ + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 16), + /* *(u32 *)(r10 - 4) = r2 */ + BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_2, -4), + /* r1 = xskmap[] */ + BPF_LD_MAP_FD(BPF_REG_1, ctx->xsks_map_fd), + /* r3 = XDP_PASS */ + BPF_MOV64_IMM(BPF_REG_3, 2), + /* call bpf_redirect_map */ + BPF_EMIT_CALL(BPF_FUNC_redirect_map), + /* if w0 != 0 goto pc+13 */ + BPF_JMP32_IMM(BPF_JSGT, BPF_REG_0, 0, 13), + /* r2 = r10 */ + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + /* r2 += -4 */ + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), + /* r1 = xskmap[] */ + BPF_LD_MAP_FD(BPF_REG_1, ctx->xsks_map_fd), + /* call bpf_map_lookup_elem */ + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + /* r1 = r0 */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), + /* r0 = XDP_PASS */ + BPF_MOV64_IMM(BPF_REG_0, 2), + /* if r1 == 0 goto pc+5 */ + BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 5), + /* r2 = *(u32 *)(r10 - 4) */ + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_10, -4), + /* r1 = xskmap[] */ + BPF_LD_MAP_FD(BPF_REG_1, ctx->xsks_map_fd), + /* r3 = 0 */ + BPF_MOV64_IMM(BPF_REG_3, 0), + /* call bpf_redirect_map */ + BPF_EMIT_CALL(BPF_FUNC_redirect_map), + /* The jumps are to this instruction */ + BPF_EXIT_INSN(), + }; + size_t insns_cnt = sizeof(prog) / sizeof(struct bpf_insn); + + prog_fd = bpf_load_program(BPF_PROG_TYPE_XDP, prog, insns_cnt, + "LGPL-2.1 or BSD-2-Clause", 0, log_buf, + log_buf_size); + if (prog_fd < 0) { + pr_warn("BPF log buffer:\n%s", log_buf); + return prog_fd; + } + + err = bpf_set_link_xdp_fd(xsk->ctx->ifindex, prog_fd, + xsk->config.xdp_flags); + if (err) { + close(prog_fd); + return err; + } + + ctx->prog_fd = prog_fd; + return 0; +} + +static int xsk_get_max_queues(struct xsk_socket *xsk) +{ + struct ethtool_channels channels = { .cmd = ETHTOOL_GCHANNELS }; + struct xsk_ctx *ctx = xsk->ctx; + struct ifreq ifr = {}; + int fd, err, ret; + + fd = socket(AF_INET, SOCK_DGRAM, 0); + if (fd < 0) + return -errno; + + ifr.ifr_data = (void *)&channels; + memcpy(ifr.ifr_name, ctx->ifname, IFNAMSIZ - 1); + ifr.ifr_name[IFNAMSIZ - 1] = '\0'; + err = ioctl(fd, SIOCETHTOOL, &ifr); + if (err && errno != EOPNOTSUPP) { + ret = -errno; + goto out; + } + + if (err) { + /* If the device says it has no channels, then all traffic + * is sent to a single stream, so max queues = 1. + */ + ret = 1; + } else { + /* Take the max of rx, tx, combined. Drivers return + * the number of channels in different ways. + */ + ret = max(channels.max_rx, channels.max_tx); + ret = max(ret, (int)channels.max_combined); + } + +out: + close(fd); + return ret; +} + +static int xsk_create_bpf_maps(struct xsk_socket *xsk) +{ + struct xsk_ctx *ctx = xsk->ctx; + int max_queues; + int fd; + + max_queues = xsk_get_max_queues(xsk); + if (max_queues < 0) + return max_queues; + + fd = bpf_create_map_name(BPF_MAP_TYPE_XSKMAP, "xsks_map", + sizeof(int), sizeof(int), max_queues, 0); + if (fd < 0) + return fd; + + ctx->xsks_map_fd = fd; + + return 0; +} + +static void xsk_delete_bpf_maps(struct xsk_socket *xsk) +{ + struct xsk_ctx *ctx = xsk->ctx; + + bpf_map_delete_elem(ctx->xsks_map_fd, &ctx->queue_id); + close(ctx->xsks_map_fd); +} + +static int xsk_lookup_bpf_maps(struct xsk_socket *xsk) +{ + __u32 i, *map_ids, num_maps, prog_len = sizeof(struct bpf_prog_info); + __u32 map_len = sizeof(struct bpf_map_info); + struct bpf_prog_info prog_info = {}; + struct xsk_ctx *ctx = xsk->ctx; + struct bpf_map_info map_info; + int fd, err; + + err = bpf_obj_get_info_by_fd(ctx->prog_fd, &prog_info, &prog_len); + if (err) + return err; + + num_maps = prog_info.nr_map_ids; + + map_ids = calloc(prog_info.nr_map_ids, sizeof(*map_ids)); + if (!map_ids) + return -ENOMEM; + + memset(&prog_info, 0, prog_len); + prog_info.nr_map_ids = num_maps; + prog_info.map_ids = (__u64)(unsigned long)map_ids; + + err = bpf_obj_get_info_by_fd(ctx->prog_fd, &prog_info, &prog_len); + if (err) + goto out_map_ids; + + ctx->xsks_map_fd = -1; + + for (i = 0; i < prog_info.nr_map_ids; i++) { + fd = bpf_map_get_fd_by_id(map_ids[i]); + if (fd < 0) + continue; + + memset(&map_info, 0, map_len); + err = bpf_obj_get_info_by_fd(fd, &map_info, &map_len); + if (err) { + close(fd); + continue; + } + + if (!strncmp(map_info.name, "xsks_map", sizeof(map_info.name))) { + ctx->xsks_map_fd = fd; + break; + } + + close(fd); + } + + err = 0; + if (ctx->xsks_map_fd == -1) + err = -ENOENT; + +out_map_ids: + free(map_ids); + return err; +} + +static int xsk_set_bpf_maps(struct xsk_socket *xsk) +{ + struct xsk_ctx *ctx = xsk->ctx; + + return bpf_map_update_elem(ctx->xsks_map_fd, &ctx->queue_id, + &xsk->fd, 0); +} + +static int xsk_setup_xdp_prog(struct xsk_socket *xsk) +{ + struct xsk_ctx *ctx = xsk->ctx; + __u32 prog_id = 0; + int err; + + err = bpf_get_link_xdp_id(ctx->ifindex, &prog_id, + xsk->config.xdp_flags); + if (err) + return err; + + if (!prog_id) { + err = xsk_create_bpf_maps(xsk); + if (err) + return err; + + err = xsk_load_xdp_prog(xsk); + if (err) { + xsk_delete_bpf_maps(xsk); + return err; + } + } else { + ctx->prog_fd = bpf_prog_get_fd_by_id(prog_id); + if (ctx->prog_fd < 0) + return -errno; + err = xsk_lookup_bpf_maps(xsk); + if (err) { + close(ctx->prog_fd); + return err; + } + } + + if (xsk->rx) + err = xsk_set_bpf_maps(xsk); + if (err) { + xsk_delete_bpf_maps(xsk); + close(ctx->prog_fd); + return err; + } + + return 0; +} + +static struct xsk_ctx *xsk_get_ctx(struct xsk_umem *umem, int ifindex, + __u32 queue_id) +{ + struct xsk_ctx *ctx; + + if (list_empty(&umem->ctx_list)) + return NULL; + + list_for_each_entry(ctx, &umem->ctx_list, list) { + if (ctx->ifindex == ifindex && ctx->queue_id == queue_id) { + ctx->refcount++; + return ctx; + } + } + + return NULL; +} + +static void xsk_put_ctx(struct xsk_ctx *ctx, bool unmap) +{ + struct xsk_umem *umem = ctx->umem; + struct xdp_mmap_offsets off; + int err; + + if (--ctx->refcount) + return; + + if (!unmap) + goto out_free; + + err = xsk_get_mmap_offsets(umem->fd, &off); + if (err) + goto out_free; + + munmap(ctx->fill->ring - off.fr.desc, off.fr.desc + umem->config.fill_size * + sizeof(__u64)); + munmap(ctx->comp->ring - off.cr.desc, off.cr.desc + umem->config.comp_size * + sizeof(__u64)); + +out_free: + list_del(&ctx->list); + free(ctx); +} + +static struct xsk_ctx *xsk_create_ctx(struct xsk_socket *xsk, + struct xsk_umem *umem, int ifindex, + const char *ifname, __u32 queue_id, + struct xsk_ring_prod *fill, + struct xsk_ring_cons *comp) +{ + struct xsk_ctx *ctx; + int err; + + ctx = calloc(1, sizeof(*ctx)); + if (!ctx) + return NULL; + + if (!umem->fill_save) { + err = xsk_create_umem_rings(umem, xsk->fd, fill, comp); + if (err) { + free(ctx); + return NULL; + } + } else if (umem->fill_save != fill || umem->comp_save != comp) { + /* Copy over rings to new structs. */ + memcpy(fill, umem->fill_save, sizeof(*fill)); + memcpy(comp, umem->comp_save, sizeof(*comp)); + } + + ctx->ifindex = ifindex; + ctx->refcount = 1; + ctx->umem = umem; + ctx->queue_id = queue_id; + memcpy(ctx->ifname, ifname, IFNAMSIZ - 1); + ctx->ifname[IFNAMSIZ - 1] = '\0'; + + ctx->fill = fill; + ctx->comp = comp; + list_add(&ctx->list, &umem->ctx_list); + return ctx; +} + +int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, + const char *ifname, + __u32 queue_id, struct xsk_umem *umem, + struct xsk_ring_cons *rx, + struct xsk_ring_prod *tx, + struct xsk_ring_prod *fill, + struct xsk_ring_cons *comp, + const struct xsk_socket_config *usr_config) +{ + bool unmap, rx_setup_done = false, tx_setup_done = false; + void *rx_map = NULL, *tx_map = NULL; + struct sockaddr_xdp sxdp = {}; + struct xdp_mmap_offsets off; + struct xsk_socket *xsk; + struct xsk_ctx *ctx; + int err, ifindex; + + if (!umem || !xsk_ptr || !(rx || tx)) + return -EFAULT; + + unmap = umem->fill_save != fill; + + xsk = calloc(1, sizeof(*xsk)); + if (!xsk) + return -ENOMEM; + + err = xsk_set_xdp_socket_config(&xsk->config, usr_config); + if (err) + goto out_xsk_alloc; + + xsk->outstanding_tx = 0; + ifindex = if_nametoindex(ifname); + if (!ifindex) { + err = -errno; + goto out_xsk_alloc; + } + + if (umem->refcount++ > 0) { + xsk->fd = socket(AF_XDP, SOCK_RAW, 0); + if (xsk->fd < 0) { + err = -errno; + goto out_xsk_alloc; + } + } else { + xsk->fd = umem->fd; + rx_setup_done = umem->rx_ring_setup_done; + tx_setup_done = umem->tx_ring_setup_done; + } + + ctx = xsk_get_ctx(umem, ifindex, queue_id); + if (!ctx) { + if (!fill || !comp) { + err = -EFAULT; + goto out_socket; + } + + ctx = xsk_create_ctx(xsk, umem, ifindex, ifname, queue_id, + fill, comp); + if (!ctx) { + err = -ENOMEM; + goto out_socket; + } + } + xsk->ctx = ctx; + + if (rx && !rx_setup_done) { + err = setsockopt(xsk->fd, SOL_XDP, XDP_RX_RING, + &xsk->config.rx_size, + sizeof(xsk->config.rx_size)); + if (err) { + err = -errno; + goto out_put_ctx; + } + if (xsk->fd == umem->fd) + umem->rx_ring_setup_done = true; + } + if (tx && !tx_setup_done) { + err = setsockopt(xsk->fd, SOL_XDP, XDP_TX_RING, + &xsk->config.tx_size, + sizeof(xsk->config.tx_size)); + if (err) { + err = -errno; + goto out_put_ctx; + } + if (xsk->fd == umem->fd) + umem->tx_ring_setup_done = true; + } + + err = xsk_get_mmap_offsets(xsk->fd, &off); + if (err) { + err = -errno; + goto out_put_ctx; + } + + if (rx) { + rx_map = mmap(NULL, off.rx.desc + + xsk->config.rx_size * sizeof(struct xdp_desc), + PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, + xsk->fd, XDP_PGOFF_RX_RING); + if (rx_map == MAP_FAILED) { + err = -errno; + goto out_put_ctx; + } + + rx->mask = xsk->config.rx_size - 1; + rx->size = xsk->config.rx_size; + rx->producer = rx_map + off.rx.producer; + rx->consumer = rx_map + off.rx.consumer; + rx->flags = rx_map + off.rx.flags; + rx->ring = rx_map + off.rx.desc; + rx->cached_prod = *rx->producer; + rx->cached_cons = *rx->consumer; + } + xsk->rx = rx; + + if (tx) { + tx_map = mmap(NULL, off.tx.desc + + xsk->config.tx_size * sizeof(struct xdp_desc), + PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, + xsk->fd, XDP_PGOFF_TX_RING); + if (tx_map == MAP_FAILED) { + err = -errno; + goto out_mmap_rx; + } + + tx->mask = xsk->config.tx_size - 1; + tx->size = xsk->config.tx_size; + tx->producer = tx_map + off.tx.producer; + tx->consumer = tx_map + off.tx.consumer; + tx->flags = tx_map + off.tx.flags; + tx->ring = tx_map + off.tx.desc; + tx->cached_prod = *tx->producer; + /* cached_cons is r->size bigger than the real consumer pointer + * See xsk_prod_nb_free + */ + tx->cached_cons = *tx->consumer + xsk->config.tx_size; + } + xsk->tx = tx; + + sxdp.sxdp_family = PF_XDP; + sxdp.sxdp_ifindex = ctx->ifindex; + sxdp.sxdp_queue_id = ctx->queue_id; + if (umem->refcount > 1) { + sxdp.sxdp_flags |= XDP_SHARED_UMEM; + sxdp.sxdp_shared_umem_fd = umem->fd; + } else { + sxdp.sxdp_flags = xsk->config.bind_flags; + } + + err = bind(xsk->fd, (struct sockaddr *)&sxdp, sizeof(sxdp)); + if (err) { + err = -errno; + goto out_mmap_tx; + } + + if (!(xsk->config.libbpf_flags & XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD)) { + err = xsk_setup_xdp_prog(xsk); + if (err) + goto out_mmap_tx; + } + + *xsk_ptr = xsk; + umem->fill_save = NULL; + umem->comp_save = NULL; + return 0; + +out_mmap_tx: + if (tx) + munmap(tx_map, off.tx.desc + + xsk->config.tx_size * sizeof(struct xdp_desc)); +out_mmap_rx: + if (rx) + munmap(rx_map, off.rx.desc + + xsk->config.rx_size * sizeof(struct xdp_desc)); +out_put_ctx: + xsk_put_ctx(ctx, unmap); +out_socket: + if (--umem->refcount) + close(xsk->fd); +out_xsk_alloc: + free(xsk); + return err; +} + +int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, + __u32 queue_id, struct xsk_umem *umem, + struct xsk_ring_cons *rx, struct xsk_ring_prod *tx, + const struct xsk_socket_config *usr_config) +{ + if (!umem) + return -EFAULT; + + return xsk_socket__create_shared(xsk_ptr, ifname, queue_id, umem, + rx, tx, umem->fill_save, + umem->comp_save, usr_config); +} + +int xsk_umem__delete(struct xsk_umem *umem) +{ + struct xdp_mmap_offsets off; + int err; + + if (!umem) + return 0; + + if (umem->refcount) + return -EBUSY; + + err = xsk_get_mmap_offsets(umem->fd, &off); + if (!err && umem->fill_save && umem->comp_save) { + munmap(umem->fill_save->ring - off.fr.desc, + off.fr.desc + umem->config.fill_size * sizeof(__u64)); + munmap(umem->comp_save->ring - off.cr.desc, + off.cr.desc + umem->config.comp_size * sizeof(__u64)); + } + + close(umem->fd); + free(umem); + + return 0; +} + +void xsk_socket__delete(struct xsk_socket *xsk) +{ + size_t desc_sz = sizeof(struct xdp_desc); + struct xdp_mmap_offsets off; + struct xsk_umem *umem; + struct xsk_ctx *ctx; + int err; + + if (!xsk) + return; + + ctx = xsk->ctx; + umem = ctx->umem; + + if (ctx->refcount == 1) { + xsk_delete_bpf_maps(xsk); + close(ctx->prog_fd); + } + + xsk_put_ctx(ctx, true); + + err = xsk_get_mmap_offsets(xsk->fd, &off); + if (!err) { + if (xsk->rx) { + munmap(xsk->rx->ring - off.rx.desc, + off.rx.desc + xsk->config.rx_size * desc_sz); + } + if (xsk->tx) { + munmap(xsk->tx->ring - off.tx.desc, + off.tx.desc + xsk->config.tx_size * desc_sz); + } + } + + umem->refcount--; + /* Do not close an fd that also has an associated umem connected + * to it. + */ + if (xsk->fd != umem->fd) + close(xsk->fd); + free(xsk); +} diff --git a/tools/lib/bpf/xsk.h b/tools/lib/bpf/xsk.h new file mode 100644 index 000000000..1069c4636 --- /dev/null +++ b/tools/lib/bpf/xsk.h @@ -0,0 +1,255 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ + +/* + * AF_XDP user-space access library. + * + * Copyright(c) 2018 - 2019 Intel Corporation. + * + * Author(s): Magnus Karlsson <magnus.karlsson@intel.com> + */ + +#ifndef __LIBBPF_XSK_H +#define __LIBBPF_XSK_H + +#include <stdio.h> +#include <stdint.h> +#include <linux/if_xdp.h> + +#include "libbpf.h" +#include "libbpf_util.h" + +#ifdef __cplusplus +extern "C" { +#endif + +/* Do not access these members directly. Use the functions below. */ +#define DEFINE_XSK_RING(name) \ +struct name { \ + __u32 cached_prod; \ + __u32 cached_cons; \ + __u32 mask; \ + __u32 size; \ + __u32 *producer; \ + __u32 *consumer; \ + void *ring; \ + __u32 *flags; \ +} + +DEFINE_XSK_RING(xsk_ring_prod); +DEFINE_XSK_RING(xsk_ring_cons); + +/* For a detailed explanation on the memory barriers associated with the + * ring, please take a look at net/xdp/xsk_queue.h. + */ + +struct xsk_umem; +struct xsk_socket; + +static inline __u64 *xsk_ring_prod__fill_addr(struct xsk_ring_prod *fill, + __u32 idx) +{ + __u64 *addrs = (__u64 *)fill->ring; + + return &addrs[idx & fill->mask]; +} + +static inline const __u64 * +xsk_ring_cons__comp_addr(const struct xsk_ring_cons *comp, __u32 idx) +{ + const __u64 *addrs = (const __u64 *)comp->ring; + + return &addrs[idx & comp->mask]; +} + +static inline struct xdp_desc *xsk_ring_prod__tx_desc(struct xsk_ring_prod *tx, + __u32 idx) +{ + struct xdp_desc *descs = (struct xdp_desc *)tx->ring; + + return &descs[idx & tx->mask]; +} + +static inline const struct xdp_desc * +xsk_ring_cons__rx_desc(const struct xsk_ring_cons *rx, __u32 idx) +{ + const struct xdp_desc *descs = (const struct xdp_desc *)rx->ring; + + return &descs[idx & rx->mask]; +} + +static inline int xsk_ring_prod__needs_wakeup(const struct xsk_ring_prod *r) +{ + return *r->flags & XDP_RING_NEED_WAKEUP; +} + +static inline __u32 xsk_prod_nb_free(struct xsk_ring_prod *r, __u32 nb) +{ + __u32 free_entries = r->cached_cons - r->cached_prod; + + if (free_entries >= nb) + return free_entries; + + /* Refresh the local tail pointer. + * cached_cons is r->size bigger than the real consumer pointer so + * that this addition can be avoided in the more frequently + * executed code that computs free_entries in the beginning of + * this function. Without this optimization it whould have been + * free_entries = r->cached_prod - r->cached_cons + r->size. + */ + r->cached_cons = *r->consumer + r->size; + + return r->cached_cons - r->cached_prod; +} + +static inline __u32 xsk_cons_nb_avail(struct xsk_ring_cons *r, __u32 nb) +{ + __u32 entries = r->cached_prod - r->cached_cons; + + if (entries == 0) { + r->cached_prod = *r->producer; + entries = r->cached_prod - r->cached_cons; + } + + return (entries > nb) ? nb : entries; +} + +static inline size_t xsk_ring_prod__reserve(struct xsk_ring_prod *prod, + size_t nb, __u32 *idx) +{ + if (xsk_prod_nb_free(prod, nb) < nb) + return 0; + + *idx = prod->cached_prod; + prod->cached_prod += nb; + + return nb; +} + +static inline void xsk_ring_prod__submit(struct xsk_ring_prod *prod, size_t nb) +{ + /* Make sure everything has been written to the ring before indicating + * this to the kernel by writing the producer pointer. + */ + libbpf_smp_wmb(); + + *prod->producer += nb; +} + +static inline size_t xsk_ring_cons__peek(struct xsk_ring_cons *cons, + size_t nb, __u32 *idx) +{ + size_t entries = xsk_cons_nb_avail(cons, nb); + + if (entries > 0) { + /* Make sure we do not speculatively read the data before + * we have received the packet buffers from the ring. + */ + libbpf_smp_rmb(); + + *idx = cons->cached_cons; + cons->cached_cons += entries; + } + + return entries; +} + +static inline void xsk_ring_cons__release(struct xsk_ring_cons *cons, size_t nb) +{ + /* Make sure data has been read before indicating we are done + * with the entries by updating the consumer pointer. + */ + libbpf_smp_rwmb(); + + *cons->consumer += nb; +} + +static inline void *xsk_umem__get_data(void *umem_area, __u64 addr) +{ + return &((char *)umem_area)[addr]; +} + +static inline __u64 xsk_umem__extract_addr(__u64 addr) +{ + return addr & XSK_UNALIGNED_BUF_ADDR_MASK; +} + +static inline __u64 xsk_umem__extract_offset(__u64 addr) +{ + return addr >> XSK_UNALIGNED_BUF_OFFSET_SHIFT; +} + +static inline __u64 xsk_umem__add_offset_to_addr(__u64 addr) +{ + return xsk_umem__extract_addr(addr) + xsk_umem__extract_offset(addr); +} + +LIBBPF_API int xsk_umem__fd(const struct xsk_umem *umem); +LIBBPF_API int xsk_socket__fd(const struct xsk_socket *xsk); + +#define XSK_RING_CONS__DEFAULT_NUM_DESCS 2048 +#define XSK_RING_PROD__DEFAULT_NUM_DESCS 2048 +#define XSK_UMEM__DEFAULT_FRAME_SHIFT 12 /* 4096 bytes */ +#define XSK_UMEM__DEFAULT_FRAME_SIZE (1 << XSK_UMEM__DEFAULT_FRAME_SHIFT) +#define XSK_UMEM__DEFAULT_FRAME_HEADROOM 0 +#define XSK_UMEM__DEFAULT_FLAGS 0 + +struct xsk_umem_config { + __u32 fill_size; + __u32 comp_size; + __u32 frame_size; + __u32 frame_headroom; + __u32 flags; +}; + +/* Flags for the libbpf_flags field. */ +#define XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD (1 << 0) + +struct xsk_socket_config { + __u32 rx_size; + __u32 tx_size; + __u32 libbpf_flags; + __u32 xdp_flags; + __u16 bind_flags; +}; + +/* Set config to NULL to get the default configuration. */ +LIBBPF_API int xsk_umem__create(struct xsk_umem **umem, + void *umem_area, __u64 size, + struct xsk_ring_prod *fill, + struct xsk_ring_cons *comp, + const struct xsk_umem_config *config); +LIBBPF_API int xsk_umem__create_v0_0_2(struct xsk_umem **umem, + void *umem_area, __u64 size, + struct xsk_ring_prod *fill, + struct xsk_ring_cons *comp, + const struct xsk_umem_config *config); +LIBBPF_API int xsk_umem__create_v0_0_4(struct xsk_umem **umem, + void *umem_area, __u64 size, + struct xsk_ring_prod *fill, + struct xsk_ring_cons *comp, + const struct xsk_umem_config *config); +LIBBPF_API int xsk_socket__create(struct xsk_socket **xsk, + const char *ifname, __u32 queue_id, + struct xsk_umem *umem, + struct xsk_ring_cons *rx, + struct xsk_ring_prod *tx, + const struct xsk_socket_config *config); +LIBBPF_API int +xsk_socket__create_shared(struct xsk_socket **xsk_ptr, + const char *ifname, + __u32 queue_id, struct xsk_umem *umem, + struct xsk_ring_cons *rx, + struct xsk_ring_prod *tx, + struct xsk_ring_prod *fill, + struct xsk_ring_cons *comp, + const struct xsk_socket_config *config); + +/* Returns 0 for success and -EBUSY if the umem is still in use. */ +LIBBPF_API int xsk_umem__delete(struct xsk_umem *umem); +LIBBPF_API void xsk_socket__delete(struct xsk_socket *xsk); + +#ifdef __cplusplus +} /* extern "C" */ +#endif + +#endif /* __LIBBPF_XSK_H */ |