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Diffstat (limited to 'src/libbpf.c')
| -rw-r--r-- | src/libbpf.c | 12490 |
1 files changed, 12490 insertions, 0 deletions
diff --git a/src/libbpf.c b/src/libbpf.c new file mode 100644 index 0000000..a5c67a3 --- /dev/null +++ b/src/libbpf.c @@ -0,0 +1,12490 @@ +// 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/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" +#include "bpf_gen_internal.h" + +#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 bool prog_is_subprog(const struct bpf_object *obj, const struct bpf_program *prog); + +static const char * const attach_type_name[] = { + [BPF_CGROUP_INET_INGRESS] = "cgroup_inet_ingress", + [BPF_CGROUP_INET_EGRESS] = "cgroup_inet_egress", + [BPF_CGROUP_INET_SOCK_CREATE] = "cgroup_inet_sock_create", + [BPF_CGROUP_INET_SOCK_RELEASE] = "cgroup_inet_sock_release", + [BPF_CGROUP_SOCK_OPS] = "cgroup_sock_ops", + [BPF_CGROUP_DEVICE] = "cgroup_device", + [BPF_CGROUP_INET4_BIND] = "cgroup_inet4_bind", + [BPF_CGROUP_INET6_BIND] = "cgroup_inet6_bind", + [BPF_CGROUP_INET4_CONNECT] = "cgroup_inet4_connect", + [BPF_CGROUP_INET6_CONNECT] = "cgroup_inet6_connect", + [BPF_CGROUP_INET4_POST_BIND] = "cgroup_inet4_post_bind", + [BPF_CGROUP_INET6_POST_BIND] = "cgroup_inet6_post_bind", + [BPF_CGROUP_INET4_GETPEERNAME] = "cgroup_inet4_getpeername", + [BPF_CGROUP_INET6_GETPEERNAME] = "cgroup_inet6_getpeername", + [BPF_CGROUP_INET4_GETSOCKNAME] = "cgroup_inet4_getsockname", + [BPF_CGROUP_INET6_GETSOCKNAME] = "cgroup_inet6_getsockname", + [BPF_CGROUP_UDP4_SENDMSG] = "cgroup_udp4_sendmsg", + [BPF_CGROUP_UDP6_SENDMSG] = "cgroup_udp6_sendmsg", + [BPF_CGROUP_SYSCTL] = "cgroup_sysctl", + [BPF_CGROUP_UDP4_RECVMSG] = "cgroup_udp4_recvmsg", + [BPF_CGROUP_UDP6_RECVMSG] = "cgroup_udp6_recvmsg", + [BPF_CGROUP_GETSOCKOPT] = "cgroup_getsockopt", + [BPF_CGROUP_SETSOCKOPT] = "cgroup_setsockopt", + [BPF_SK_SKB_STREAM_PARSER] = "sk_skb_stream_parser", + [BPF_SK_SKB_STREAM_VERDICT] = "sk_skb_stream_verdict", + [BPF_SK_SKB_VERDICT] = "sk_skb_verdict", + [BPF_SK_MSG_VERDICT] = "sk_msg_verdict", + [BPF_LIRC_MODE2] = "lirc_mode2", + [BPF_FLOW_DISSECTOR] = "flow_dissector", + [BPF_TRACE_RAW_TP] = "trace_raw_tp", + [BPF_TRACE_FENTRY] = "trace_fentry", + [BPF_TRACE_FEXIT] = "trace_fexit", + [BPF_MODIFY_RETURN] = "modify_return", + [BPF_LSM_MAC] = "lsm_mac", + [BPF_LSM_CGROUP] = "lsm_cgroup", + [BPF_SK_LOOKUP] = "sk_lookup", + [BPF_TRACE_ITER] = "trace_iter", + [BPF_XDP_DEVMAP] = "xdp_devmap", + [BPF_XDP_CPUMAP] = "xdp_cpumap", + [BPF_XDP] = "xdp", + [BPF_SK_REUSEPORT_SELECT] = "sk_reuseport_select", + [BPF_SK_REUSEPORT_SELECT_OR_MIGRATE] = "sk_reuseport_select_or_migrate", + [BPF_PERF_EVENT] = "perf_event", + [BPF_TRACE_KPROBE_MULTI] = "trace_kprobe_multi", +}; + +static const char * const link_type_name[] = { + [BPF_LINK_TYPE_UNSPEC] = "unspec", + [BPF_LINK_TYPE_RAW_TRACEPOINT] = "raw_tracepoint", + [BPF_LINK_TYPE_TRACING] = "tracing", + [BPF_LINK_TYPE_CGROUP] = "cgroup", + [BPF_LINK_TYPE_ITER] = "iter", + [BPF_LINK_TYPE_NETNS] = "netns", + [BPF_LINK_TYPE_XDP] = "xdp", + [BPF_LINK_TYPE_PERF_EVENT] = "perf_event", + [BPF_LINK_TYPE_KPROBE_MULTI] = "kprobe_multi", + [BPF_LINK_TYPE_STRUCT_OPS] = "struct_ops", +}; + +static const char * const map_type_name[] = { + [BPF_MAP_TYPE_UNSPEC] = "unspec", + [BPF_MAP_TYPE_HASH] = "hash", + [BPF_MAP_TYPE_ARRAY] = "array", + [BPF_MAP_TYPE_PROG_ARRAY] = "prog_array", + [BPF_MAP_TYPE_PERF_EVENT_ARRAY] = "perf_event_array", + [BPF_MAP_TYPE_PERCPU_HASH] = "percpu_hash", + [BPF_MAP_TYPE_PERCPU_ARRAY] = "percpu_array", + [BPF_MAP_TYPE_STACK_TRACE] = "stack_trace", + [BPF_MAP_TYPE_CGROUP_ARRAY] = "cgroup_array", + [BPF_MAP_TYPE_LRU_HASH] = "lru_hash", + [BPF_MAP_TYPE_LRU_PERCPU_HASH] = "lru_percpu_hash", + [BPF_MAP_TYPE_LPM_TRIE] = "lpm_trie", + [BPF_MAP_TYPE_ARRAY_OF_MAPS] = "array_of_maps", + [BPF_MAP_TYPE_HASH_OF_MAPS] = "hash_of_maps", + [BPF_MAP_TYPE_DEVMAP] = "devmap", + [BPF_MAP_TYPE_DEVMAP_HASH] = "devmap_hash", + [BPF_MAP_TYPE_SOCKMAP] = "sockmap", + [BPF_MAP_TYPE_CPUMAP] = "cpumap", + [BPF_MAP_TYPE_XSKMAP] = "xskmap", + [BPF_MAP_TYPE_SOCKHASH] = "sockhash", + [BPF_MAP_TYPE_CGROUP_STORAGE] = "cgroup_storage", + [BPF_MAP_TYPE_REUSEPORT_SOCKARRAY] = "reuseport_sockarray", + [BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE] = "percpu_cgroup_storage", + [BPF_MAP_TYPE_QUEUE] = "queue", + [BPF_MAP_TYPE_STACK] = "stack", + [BPF_MAP_TYPE_SK_STORAGE] = "sk_storage", + [BPF_MAP_TYPE_STRUCT_OPS] = "struct_ops", + [BPF_MAP_TYPE_RINGBUF] = "ringbuf", + [BPF_MAP_TYPE_INODE_STORAGE] = "inode_storage", + [BPF_MAP_TYPE_TASK_STORAGE] = "task_storage", + [BPF_MAP_TYPE_BLOOM_FILTER] = "bloom_filter", + [BPF_MAP_TYPE_USER_RINGBUF] = "user_ringbuf", + [BPF_MAP_TYPE_CGRP_STORAGE] = "cgrp_storage", +}; + +static const char * const prog_type_name[] = { + [BPF_PROG_TYPE_UNSPEC] = "unspec", + [BPF_PROG_TYPE_SOCKET_FILTER] = "socket_filter", + [BPF_PROG_TYPE_KPROBE] = "kprobe", + [BPF_PROG_TYPE_SCHED_CLS] = "sched_cls", + [BPF_PROG_TYPE_SCHED_ACT] = "sched_act", + [BPF_PROG_TYPE_TRACEPOINT] = "tracepoint", + [BPF_PROG_TYPE_XDP] = "xdp", + [BPF_PROG_TYPE_PERF_EVENT] = "perf_event", + [BPF_PROG_TYPE_CGROUP_SKB] = "cgroup_skb", + [BPF_PROG_TYPE_CGROUP_SOCK] = "cgroup_sock", + [BPF_PROG_TYPE_LWT_IN] = "lwt_in", + [BPF_PROG_TYPE_LWT_OUT] = "lwt_out", + [BPF_PROG_TYPE_LWT_XMIT] = "lwt_xmit", + [BPF_PROG_TYPE_SOCK_OPS] = "sock_ops", + [BPF_PROG_TYPE_SK_SKB] = "sk_skb", + [BPF_PROG_TYPE_CGROUP_DEVICE] = "cgroup_device", + [BPF_PROG_TYPE_SK_MSG] = "sk_msg", + [BPF_PROG_TYPE_RAW_TRACEPOINT] = "raw_tracepoint", + [BPF_PROG_TYPE_CGROUP_SOCK_ADDR] = "cgroup_sock_addr", + [BPF_PROG_TYPE_LWT_SEG6LOCAL] = "lwt_seg6local", + [BPF_PROG_TYPE_LIRC_MODE2] = "lirc_mode2", + [BPF_PROG_TYPE_SK_REUSEPORT] = "sk_reuseport", + [BPF_PROG_TYPE_FLOW_DISSECTOR] = "flow_dissector", + [BPF_PROG_TYPE_CGROUP_SYSCTL] = "cgroup_sysctl", + [BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE] = "raw_tracepoint_writable", + [BPF_PROG_TYPE_CGROUP_SOCKOPT] = "cgroup_sockopt", + [BPF_PROG_TYPE_TRACING] = "tracing", + [BPF_PROG_TYPE_STRUCT_OPS] = "struct_ops", + [BPF_PROG_TYPE_EXT] = "ext", + [BPF_PROG_TYPE_LSM] = "lsm", + [BPF_PROG_TYPE_SK_LOOKUP] = "sk_lookup", + [BPF_PROG_TYPE_SYSCALL] = "syscall", +}; + +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; + int old_errno; + + if (!__libbpf_pr) + return; + + old_errno = errno; + + va_start(args, format); + __libbpf_pr(level, format, args); + va_end(args); + + errno = old_errno; +} + +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; +} + +int libbpf_set_strict_mode(enum libbpf_strict_mode mode) +{ + /* as of v1.0 libbpf_set_strict_mode() is a no-op */ + return 0; +} + +__u32 libbpf_major_version(void) +{ + return LIBBPF_MAJOR_VERSION; +} + +__u32 libbpf_minor_version(void) +{ + return LIBBPF_MINOR_VERSION; +} + +const char *libbpf_version_string(void) +{ +#define __S(X) #X +#define _S(X) __S(X) + return "v" _S(LIBBPF_MAJOR_VERSION) "." _S(LIBBPF_MINOR_VERSION); +#undef _S +#undef __S +} + +enum reloc_type { + RELO_LD64, + RELO_CALL, + RELO_DATA, + RELO_EXTERN_VAR, + RELO_EXTERN_FUNC, + RELO_SUBPROG_ADDR, + RELO_CORE, +}; + +struct reloc_desc { + enum reloc_type type; + int insn_idx; + union { + const struct bpf_core_relo *core_relo; /* used when type == RELO_CORE */ + struct { + int map_idx; + int sym_off; + }; + }; +}; + +/* stored as sec_def->cookie for all libbpf-supported SEC()s */ +enum sec_def_flags { + SEC_NONE = 0, + /* expected_attach_type is optional, if kernel doesn't support that */ + SEC_EXP_ATTACH_OPT = 1, + /* legacy, only used by libbpf_get_type_names() and + * libbpf_attach_type_by_name(), not used by libbpf itself at all. + * This used to be associated with cgroup (and few other) BPF programs + * that were attachable through BPF_PROG_ATTACH command. Pretty + * meaningless nowadays, though. + */ + SEC_ATTACHABLE = 2, + SEC_ATTACHABLE_OPT = SEC_ATTACHABLE | SEC_EXP_ATTACH_OPT, + /* attachment target is specified through BTF ID in either kernel or + * other BPF program's BTF object + */ + SEC_ATTACH_BTF = 4, + /* BPF program type allows sleeping/blocking in kernel */ + SEC_SLEEPABLE = 8, + /* BPF program support non-linear XDP buffer */ + SEC_XDP_FRAGS = 16, +}; + +struct bpf_sec_def { + char *sec; + enum bpf_prog_type prog_type; + enum bpf_attach_type expected_attach_type; + long cookie; + int handler_id; + + libbpf_prog_setup_fn_t prog_setup_fn; + libbpf_prog_prepare_load_fn_t prog_prepare_load_fn; + libbpf_prog_attach_fn_t prog_attach_fn; +}; + +/* + * bpf_prog should be a better name but it has been used in + * linux/filter.h. + */ +struct bpf_program { + char *name; + char *sec_name; + size_t sec_idx; + const struct bpf_sec_def *sec_def; + /* 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; + + /* 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; + + /* BPF verifier log settings */ + char *log_buf; + size_t log_size; + __u32 log_level; + + struct bpf_object *obj; + + int fd; + bool autoload; + bool autoattach; + bool mark_btf_static; + enum bpf_prog_type type; + enum bpf_attach_type expected_attach_type; + + int prog_ifindex; + __u32 attach_btf_obj_fd; + __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, +}; + +struct bpf_map_def { + unsigned int type; + unsigned int key_size; + unsigned int value_size; + unsigned int max_entries; + unsigned int map_flags; +}; + +struct bpf_map { + struct bpf_object *obj; + char *name; + /* real_name is defined for special internal maps (.rodata*, + * .data*, .bss, .kconfig) and preserves their original ELF section + * name. This is important to be able to find corresponding BTF + * DATASEC information. + */ + char *real_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; + 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; + bool autocreate; + __u64 map_extra; +}; + +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 kernel_btf_obj_fd; + int kernel_btf_id; + + /* local btf_id of the ksym extern's type. */ + __u32 type_id; + /* BTF fd index to be patched in for insn->off, this is + * 0 for vmlinux BTF, index in obj->fd_array for module + * BTF + */ + __s16 btf_fd_idx; + } ksym; + }; +}; + +struct module_btf { + struct btf *btf; + char *name; + __u32 id; + int fd; + int fd_array_idx; +}; + +enum sec_type { + SEC_UNUSED = 0, + SEC_RELO, + SEC_BSS, + SEC_DATA, + SEC_RODATA, +}; + +struct elf_sec_desc { + enum sec_type sec_type; + Elf64_Shdr *shdr; + Elf_Data *data; +}; + +struct elf_state { + int fd; + const void *obj_buf; + size_t obj_buf_sz; + Elf *elf; + Elf64_Ehdr *ehdr; + Elf_Data *symbols; + Elf_Data *st_ops_data; + size_t shstrndx; /* section index for section name strings */ + size_t strtabidx; + struct elf_sec_desc *secs; + size_t sec_cnt; + int btf_maps_shndx; + __u32 btf_maps_sec_btf_id; + int text_shndx; + int symbols_shndx; + int st_ops_shndx; +}; + +struct usdt_manager; + +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; + + bool loaded; + bool has_subcalls; + bool has_rodata; + + struct bpf_gen *gen_loader; + + /* Information when doing ELF related work. Only valid if efile.elf is not NULL */ + struct elf_state efile; + + struct btf *btf; + struct btf_ext *btf_ext; + + /* Parse and load BTF vmlinux if any of the programs in the object need + * it at load time. + */ + struct btf *btf_vmlinux; + /* Path to the custom BTF to be used for BPF CO-RE relocations as an + * override for vmlinux BTF. + */ + char *btf_custom_path; + /* vmlinux BTF override for CO-RE relocations */ + struct btf *btf_vmlinux_override; + /* Lazily initialized kernel module BTFs */ + struct module_btf *btf_modules; + bool btf_modules_loaded; + size_t btf_module_cnt; + size_t btf_module_cap; + + /* optional log settings passed to BPF_BTF_LOAD and BPF_PROG_LOAD commands */ + char *log_buf; + size_t log_size; + __u32 log_level; + + int *fd_array; + size_t fd_array_cap; + size_t fd_array_cnt; + + struct usdt_manager *usdt_man; + + char path[]; +}; + +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 Elf64_Shdr *elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn); +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 Elf64_Sym *elf_sym_by_idx(const struct bpf_object *obj, size_t idx); +static Elf64_Rel *elf_rel_by_idx(Elf_Data *data, size_t idx); + +void bpf_program__unload(struct bpf_program *prog) +{ + if (!prog) + return; + + zclose(prog->fd); + + zfree(&prog->func_info); + zfree(&prog->line_info); +} + +static void bpf_program__exit(struct bpf_program *prog) +{ + if (!prog) + return; + + bpf_program__unload(prog); + zfree(&prog->name); + zfree(&prog->sec_name); + zfree(&prog->insns); + zfree(&prog->reloc_desc); + + prog->nr_reloc = 0; + prog->insns_cnt = 0; + prog->sec_idx = -1; +} + +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 bool is_call_insn(const struct bpf_insn *insn) +{ + return insn->code == (BPF_JMP | BPF_CALL); +} + +static bool insn_is_pseudo_func(struct bpf_insn *insn) +{ + return is_ldimm64_insn(insn) && insn->src_reg == BPF_PSEUDO_FUNC; +} + +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->fd = -1; + + /* libbpf's convention for SEC("?abc...") is that it's just like + * SEC("abc...") but the corresponding bpf_program starts out with + * autoload set to false. + */ + if (sec_name[0] == '?') { + prog->autoload = false; + /* from now on forget there was ? in section name */ + sec_name++; + } else { + prog->autoload = true; + } + + prog->autoattach = true; + + /* inherit object's log_level */ + prog->log_level = obj->log_level; + + prog->sec_name = strdup(sec_name); + if (!prog->sec_name) + goto errout; + + prog->name = strdup(name); + if (!prog->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) +{ + Elf_Data *symbols = obj->efile.symbols; + struct bpf_program *prog, *progs; + void *data = sec_data->d_buf; + size_t sec_sz = sec_data->d_size, sec_off, prog_sz, nr_syms; + int nr_progs, err, i; + const char *name; + Elf64_Sym *sym; + + progs = obj->programs; + nr_progs = obj->nr_programs; + nr_syms = symbols->d_size / sizeof(Elf64_Sym); + sec_off = 0; + + for (i = 0; i < nr_syms; i++) { + sym = elf_sym_by_idx(obj, i); + + if (sym->st_shndx != sec_idx) + continue; + if (ELF64_ST_TYPE(sym->st_info) != STT_FUNC) + continue; + + prog_sz = sym->st_size; + sec_off = sym->st_value; + + 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; + } + + if (sec_idx != obj->efile.text_shndx && ELF64_ST_BIND(sym->st_info) == STB_LOCAL) { + pr_warn("sec '%s': program '%s' is static and not supported\n", sec_name, name); + return -ENOTSUP; + } + + 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; + + /* if function is a global/weak symbol, but has restricted + * (STV_HIDDEN or STV_INTERNAL) visibility, mark its BTF FUNC + * as static to enable more permissive BPF verification mode + * with more outside context available to BPF verifier + */ + if (ELF64_ST_BIND(sym->st_info) != STB_LOCAL + && (ELF64_ST_VISIBILITY(sym->st_other) == STV_HIDDEN + || ELF64_ST_VISIBILITY(sym->st_other) == STV_INTERNAL)) + prog->mark_btf_static = true; + + nr_progs++; + obj->nr_programs = nr_progs; + } + + return 0; +} + +__u32 get_kernel_version(void) +{ + /* On Ubuntu LINUX_VERSION_CODE doesn't correspond to info.release, + * but Ubuntu provides /proc/version_signature file, as described at + * https://ubuntu.com/kernel, with an example contents below, which we + * can use to get a proper LINUX_VERSION_CODE. + * + * Ubuntu 5.4.0-12.15-generic 5.4.8 + * + * In the above, 5.4.8 is what kernel is actually expecting, while + * uname() call will return 5.4.0 in info.release. + */ + const char *ubuntu_kver_file = "/proc/version_signature"; + __u32 major, minor, patch; + struct utsname info; + + if (faccessat(AT_FDCWD, ubuntu_kver_file, R_OK, AT_EACCESS) == 0) { + FILE *f; + + f = fopen(ubuntu_kver_file, "r"); + if (f) { + if (fscanf(f, "%*s %*s %d.%d.%d\n", &major, &minor, &patch) == 3) { + fclose(f); + return KERNEL_VERSION(major, minor, patch); + } + fclose(f); + } + /* something went wrong, fall back to uname() approach */ + } + + 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) { + libbpf_strlcpy(obj->name, obj_name, sizeof(obj->name)); + } else { + /* Using basename() GNU version which doesn't modify arg. */ + libbpf_strlcpy(obj->name, basename((void *)path), sizeof(obj->name)); + 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.btf_maps_shndx = -1; + obj->efile.st_ops_shndx = -1; + obj->kconfig_map_idx = -1; + + obj->kern_version = get_kernel_version(); + obj->loaded = false; + + return obj; +} + +static void bpf_object__elf_finish(struct bpf_object *obj) +{ + if (!obj->efile.elf) + return; + + elf_end(obj->efile.elf); + obj->efile.elf = NULL; + obj->efile.symbols = NULL; + obj->efile.st_ops_data = NULL; + + zfree(&obj->efile.secs); + obj->efile.sec_cnt = 0; + zclose(obj->efile.fd); + obj->efile.obj_buf = NULL; + obj->efile.obj_buf_sz = 0; +} + +static int bpf_object__elf_init(struct bpf_object *obj) +{ + Elf64_Ehdr *ehdr; + int err = 0; + Elf *elf; + + if (obj->efile.elf) { + 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_mem(). */ + elf = elf_memory((char *)obj->efile.obj_buf, obj->efile.obj_buf_sz); + } else { + obj->efile.fd = open(obj->path, O_RDONLY | O_CLOEXEC); + 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; + } + + elf = elf_begin(obj->efile.fd, ELF_C_READ_MMAP, NULL); + } + + if (!elf) { + pr_warn("elf: failed to open %s as ELF file: %s\n", obj->path, elf_errmsg(-1)); + err = -LIBBPF_ERRNO__LIBELF; + goto errout; + } + + obj->efile.elf = elf; + + if (elf_kind(elf) != ELF_K_ELF) { + err = -LIBBPF_ERRNO__FORMAT; + pr_warn("elf: '%s' is not a proper ELF object\n", obj->path); + goto errout; + } + + if (gelf_getclass(elf) != ELFCLASS64) { + err = -LIBBPF_ERRNO__FORMAT; + pr_warn("elf: '%s' is not a 64-bit ELF object\n", obj->path); + goto errout; + } + + obj->efile.ehdr = ehdr = elf64_getehdr(elf); + if (!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; + } + + if (elf_getshdrstrndx(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(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 (ehdr->e_type != ET_REL || (ehdr->e_machine && ehdr->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__ == __ORDER_LITTLE_ENDIAN__ + if (obj->efile.ehdr->e_ident[EI_DATA] == ELFDATA2LSB) + return 0; +#elif __BYTE_ORDER__ == __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) +{ + if (!data) { + pr_warn("invalid license section in %s\n", obj->path); + return -LIBBPF_ERRNO__FORMAT; + } + /* libbpf_strlcpy() only copies first N - 1 bytes, so size + 1 won't + * go over allowed ELF data section buffer + */ + libbpf_strlcpy(obj->license, data, min(size + 1, sizeof(obj->license))); + 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 (!data || 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; +} + +static int find_elf_sec_sz(const struct bpf_object *obj, const char *name, __u32 *size) +{ + Elf_Data *data; + Elf_Scn *scn; + + if (!name) + return -EINVAL; + + scn = elf_sec_by_name(obj, name); + data = elf_sec_data(obj, scn); + if (data) { + *size = data->d_size; + return 0; /* found it */ + } + + return -ENOENT; +} + +static Elf64_Sym *find_elf_var_sym(const struct bpf_object *obj, const char *name) +{ + Elf_Data *symbols = obj->efile.symbols; + const char *sname; + size_t si; + + for (si = 0; si < symbols->d_size / sizeof(Elf64_Sym); si++) { + Elf64_Sym *sym = elf_sym_by_idx(obj, si); + + if (ELF64_ST_TYPE(sym->st_info) != STT_OBJECT) + continue; + + if (ELF64_ST_BIND(sym->st_info) != STB_GLOBAL && + ELF64_ST_BIND(sym->st_info) != STB_WEAK) + 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 ERR_PTR(-EIO); + } + if (strcmp(name, sname) == 0) + return sym; + } + + return ERR_PTR(-ENOENT); +} + +static struct bpf_map *bpf_object__add_map(struct bpf_object *obj) +{ + struct bpf_map *map; + int err; + + err = libbpf_ensure_mem((void **)&obj->maps, &obj->maps_cap, + sizeof(*obj->maps), obj->nr_maps + 1); + if (err) + return ERR_PTR(err); + + map = &obj->maps[obj->nr_maps++]; + map->obj = obj; + map->fd = -1; + map->inner_map_fd = -1; + map->autocreate = true; + + return map; +} + +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, const char *real_name) +{ + char map_name[BPF_OBJ_NAME_LEN], *p; + int pfx_len, sfx_len = max((size_t)7, strlen(real_name)); + + /* This is one of the more confusing parts of libbpf for various + * reasons, some of which are historical. The original idea for naming + * internal names was to include as much of BPF object name prefix as + * possible, so that it can be distinguished from similar internal + * maps of a different BPF object. + * As an example, let's say we have bpf_object named 'my_object_name' + * and internal map corresponding to '.rodata' ELF section. The final + * map name advertised to user and to the kernel will be + * 'my_objec.rodata', taking first 8 characters of object name and + * entire 7 characters of '.rodata'. + * Somewhat confusingly, if internal map ELF section name is shorter + * than 7 characters, e.g., '.bss', we still reserve 7 characters + * for the suffix, even though we only have 4 actual characters, and + * resulting map will be called 'my_objec.bss', not even using all 15 + * characters allowed by the kernel. Oh well, at least the truncated + * object name is somewhat consistent in this case. But if the map + * name is '.kconfig', we'll still have entirety of '.kconfig' added + * (8 chars) and thus will be left with only first 7 characters of the + * object name ('my_obje'). Happy guessing, user, that the final map + * name will be "my_obje.kconfig". + * Now, with libbpf starting to support arbitrarily named .rodata.* + * and .data.* data sections, it's possible that ELF section name is + * longer than allowed 15 chars, so we now need to be careful to take + * only up to 15 first characters of ELF name, taking no BPF object + * name characters at all. So '.rodata.abracadabra' will result in + * '.rodata.abracad' kernel and user-visible name. + * We need to keep this convoluted logic intact for .data, .bss and + * .rodata maps, but for new custom .data.custom and .rodata.custom + * maps we use their ELF names as is, not prepending bpf_object name + * in front. We still need to truncate them to 15 characters for the + * kernel. Full name can be recovered for such maps by using DATASEC + * BTF type associated with such map's value type, though. + */ + if (sfx_len >= BPF_OBJ_NAME_LEN) + sfx_len = BPF_OBJ_NAME_LEN - 1; + + /* if there are two or more dots in map name, it's a custom dot map */ + if (strchr(real_name + 1, '.') != NULL) + pfx_len = 0; + else + 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, real_name); + + /* 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 +map_fill_btf_type_info(struct bpf_object *obj, struct bpf_map *map); + +/* Internal BPF map is mmap()'able only if at least one of corresponding + * DATASEC's VARs are to be exposed through BPF skeleton. I.e., it's a GLOBAL + * variable and it's not marked as __hidden (which turns it into, effectively, + * a STATIC variable). + */ +static bool map_is_mmapable(struct bpf_object *obj, struct bpf_map *map) +{ + const struct btf_type *t, *vt; + struct btf_var_secinfo *vsi; + int i, n; + + if (!map->btf_value_type_id) + return false; + + t = btf__type_by_id(obj->btf, map->btf_value_type_id); + if (!btf_is_datasec(t)) + return false; + + vsi = btf_var_secinfos(t); + for (i = 0, n = btf_vlen(t); i < n; i++, vsi++) { + vt = btf__type_by_id(obj->btf, vsi->type); + if (!btf_is_var(vt)) + continue; + + if (btf_var(vt)->linkage != BTF_VAR_STATIC) + return true; + } + + return false; +} + +static int +bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type, + const char *real_name, 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->real_name = strdup(real_name); + map->name = internal_map_name(obj, real_name); + if (!map->real_name || !map->name) { + zfree(&map->real_name); + zfree(&map->name); + 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; + + /* failures are fine because of maps like .rodata.str1.1 */ + (void) map_fill_btf_type_info(obj, map); + + if (map_is_mmapable(obj, map)) + 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->real_name); + 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) +{ + struct elf_sec_desc *sec_desc; + const char *sec_name; + int err = 0, sec_idx; + + /* + * Populate obj->maps with libbpf internal maps. + */ + for (sec_idx = 1; sec_idx < obj->efile.sec_cnt; sec_idx++) { + sec_desc = &obj->efile.secs[sec_idx]; + + /* Skip recognized sections with size 0. */ + if (!sec_desc->data || sec_desc->data->d_size == 0) + continue; + + switch (sec_desc->sec_type) { + case SEC_DATA: + sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx)); + err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA, + sec_name, sec_idx, + sec_desc->data->d_buf, + sec_desc->data->d_size); + break; + case SEC_RODATA: + obj->has_rodata = true; + sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx)); + err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA, + sec_name, sec_idx, + sec_desc->data->d_buf, + sec_desc->data->d_size); + break; + case SEC_BSS: + sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx)); + err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS, + sec_name, sec_idx, + NULL, + sec_desc->data->d_size); + break; + default: + /* skip */ + break; + } + 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': value '%c' implies tristate or char type\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': value '%c' implies bool, tristate, or char type\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': value '%s' implies char array type\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 '%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 && + ext->kcfg.type != KCFG_BOOL) { + pr_warn("extern (kcfg) '%s': value '%llu' implies integer, char, or boolean type\n", + ext->name, (unsigned long long)value); + return -EINVAL; + } + if (ext->kcfg.type == KCFG_BOOL && value > 1) { + pr_warn("extern (kcfg) '%s': value '%llu' isn't boolean compatible\n", + ext->name, (unsigned long long)value); + return -EINVAL; + + } + if (!is_kcfg_value_in_range(ext, value)) { + pr_warn("extern (kcfg) '%s': value '%llu' 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 (!str_has_pfx(buf, "CONFIG_")) + 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': value '%s' isn't a valid integer\n", ext->name, value); + return err; + } + if (ext->kcfg.type != KCFG_INT && ext->kcfg.type != KCFG_CHAR) { + pr_warn("extern (kcfg) '%s': value '%s' implies integer type\n", ext->name, value); + return -EINVAL; + } + err = set_kcfg_value_num(ext, ext_val, num); + break; + } + if (err) + return err; + pr_debug("extern (kcfg) '%s': set to %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, + ".kconfig", obj->efile.symbols_shndx, + NULL, map_sz); + if (err) + return err; + + obj->kconfig_map_idx = obj->nr_maps - 1; + + return 0; +} + +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(__u16 kind) +{ + switch (kind) { + 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"; + case BTF_KIND_FLOAT: return "float"; + case BTF_KIND_DECL_TAG: return "decl_tag"; + case BTF_KIND_TYPE_TAG: return "type_tag"; + case BTF_KIND_ENUM64: return "enum64"; + default: return "unknown"; + } +} + +const char *btf_kind_str(const struct btf_type *t) +{ + return __btf_kind_str(btf_kind(t)); +} + +/* + * 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 pathname_concat(char *buf, size_t buf_sz, const char *path, const char *name) +{ + int len; + + len = snprintf(buf, buf_sz, "%s/%s", path, name); + if (len < 0) + return -EINVAL; + if (len >= buf_sz) + return -ENAMETOOLONG; + + return 0; +} + +static int build_map_pin_path(struct bpf_map *map, const char *path) +{ + char buf[PATH_MAX]; + int err; + + if (!path) + path = "/sys/fs/bpf"; + + err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map)); + if (err) + return err; + + return bpf_map__set_pin_path(map, buf); +} + +/* should match definition in bpf_helpers.h */ +enum libbpf_pin_type { + LIBBPF_PIN_NONE, + /* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */ + LIBBPF_PIN_BY_NAME, +}; + +int parse_btf_map_def(const char *map_name, struct btf *btf, + const struct btf_type *def_t, bool strict, + struct btf_map_def *map_def, struct btf_map_def *inner_def) +{ + const struct btf_type *t; + const struct btf_member *m; + bool is_inner = inner_def == NULL; + int vlen, i; + + vlen = btf_vlen(def_t); + m = btf_members(def_t); + for (i = 0; i < vlen; i++, m++) { + const char *name = btf__name_by_offset(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, btf, m, &map_def->map_type)) + return -EINVAL; + map_def->parts |= MAP_DEF_MAP_TYPE; + } else if (strcmp(name, "max_entries") == 0) { + if (!get_map_field_int(map_name, btf, m, &map_def->max_entries)) + return -EINVAL; + map_def->parts |= MAP_DEF_MAX_ENTRIES; + } else if (strcmp(name, "map_flags") == 0) { + if (!get_map_field_int(map_name, btf, m, &map_def->map_flags)) + return -EINVAL; + map_def->parts |= MAP_DEF_MAP_FLAGS; + } else if (strcmp(name, "numa_node") == 0) { + if (!get_map_field_int(map_name, btf, m, &map_def->numa_node)) + return -EINVAL; + map_def->parts |= MAP_DEF_NUMA_NODE; + } else if (strcmp(name, "key_size") == 0) { + __u32 sz; + + if (!get_map_field_int(map_name, btf, m, &sz)) + return -EINVAL; + 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; + map_def->parts |= MAP_DEF_KEY_SIZE; + } else if (strcmp(name, "key") == 0) { + __s64 sz; + + t = btf__type_by_id(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(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; + } + 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_def->key_type_id = t->type; + map_def->parts |= MAP_DEF_KEY_SIZE | MAP_DEF_KEY_TYPE; + } else if (strcmp(name, "value_size") == 0) { + __u32 sz; + + if (!get_map_field_int(map_name, btf, m, &sz)) + return -EINVAL; + 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; + map_def->parts |= MAP_DEF_VALUE_SIZE; + } else if (strcmp(name, "value") == 0) { + __s64 sz; + + t = btf__type_by_id(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(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; + } + 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_def->value_type_id = t->type; + map_def->parts |= MAP_DEF_VALUE_SIZE | MAP_DEF_VALUE_TYPE; + } + else if (strcmp(name, "values") == 0) { + bool is_map_in_map = bpf_map_type__is_map_in_map(map_def->map_type); + bool is_prog_array = map_def->map_type == BPF_MAP_TYPE_PROG_ARRAY; + const char *desc = is_map_in_map ? "map-in-map inner" : "prog-array value"; + char inner_map_name[128]; + 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 (!is_map_in_map && !is_prog_array) { + pr_warn("map '%s': should be map-in-map or prog-array.\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(btf, m->type); + if (!t) { + pr_warn("map '%s': %s type [%d] not found.\n", + map_name, desc, m->type); + return -EINVAL; + } + if (!btf_is_array(t) || btf_array(t)->nelems) { + pr_warn("map '%s': %s spec is not a zero-sized array.\n", + map_name, desc); + return -EINVAL; + } + t = skip_mods_and_typedefs(btf, btf_array(t)->type, NULL); + if (!btf_is_ptr(t)) { + pr_warn("map '%s': %s def is of unexpected kind %s.\n", + map_name, desc, btf_kind_str(t)); + return -EINVAL; + } + t = skip_mods_and_typedefs(btf, t->type, NULL); + if (is_prog_array) { + if (!btf_is_func_proto(t)) { + pr_warn("map '%s': prog-array value def is of unexpected kind %s.\n", + map_name, btf_kind_str(t)); + return -EINVAL; + } + continue; + } + 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; + } + + snprintf(inner_map_name, sizeof(inner_map_name), "%s.inner", map_name); + err = parse_btf_map_def(inner_map_name, btf, t, strict, inner_def, NULL); + if (err) + return err; + + map_def->parts |= MAP_DEF_INNER_MAP; + } else if (strcmp(name, "pinning") == 0) { + __u32 val; + + if (is_inner) { + pr_warn("map '%s': inner def can't be pinned.\n", map_name); + return -EINVAL; + } + if (!get_map_field_int(map_name, btf, m, &val)) + return -EINVAL; + if (val != LIBBPF_PIN_NONE && val != LIBBPF_PIN_BY_NAME) { + pr_warn("map '%s': invalid pinning value %u.\n", + map_name, val); + return -EINVAL; + } + map_def->pinning = val; + map_def->parts |= MAP_DEF_PINNING; + } else if (strcmp(name, "map_extra") == 0) { + __u32 map_extra; + + if (!get_map_field_int(map_name, btf, m, &map_extra)) + return -EINVAL; + map_def->map_extra = map_extra; + map_def->parts |= MAP_DEF_MAP_EXTRA; + } 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->map_type == BPF_MAP_TYPE_UNSPEC) { + pr_warn("map '%s': map type isn't specified.\n", map_name); + return -EINVAL; + } + + return 0; +} + +static size_t adjust_ringbuf_sz(size_t sz) +{ + __u32 page_sz = sysconf(_SC_PAGE_SIZE); + __u32 mul; + + /* if user forgot to set any size, make sure they see error */ + if (sz == 0) + return 0; + /* Kernel expects BPF_MAP_TYPE_RINGBUF's max_entries to be + * a power-of-2 multiple of kernel's page size. If user diligently + * satisified these conditions, pass the size through. + */ + if ((sz % page_sz) == 0 && is_pow_of_2(sz / page_sz)) + return sz; + + /* Otherwise find closest (page_sz * power_of_2) product bigger than + * user-set size to satisfy both user size request and kernel + * requirements and substitute correct max_entries for map creation. + */ + for (mul = 1; mul <= UINT_MAX / page_sz; mul <<= 1) { + if (mul * page_sz > sz) + return mul * page_sz; + } + + /* if it's impossible to satisfy the conditions (i.e., user size is + * very close to UINT_MAX but is not a power-of-2 multiple of + * page_size) then just return original size and let kernel reject it + */ + return sz; +} + +static bool map_is_ringbuf(const struct bpf_map *map) +{ + return map->def.type == BPF_MAP_TYPE_RINGBUF || + map->def.type == BPF_MAP_TYPE_USER_RINGBUF; +} + +static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def) +{ + map->def.type = def->map_type; + map->def.key_size = def->key_size; + map->def.value_size = def->value_size; + map->def.max_entries = def->max_entries; + map->def.map_flags = def->map_flags; + map->map_extra = def->map_extra; + + map->numa_node = def->numa_node; + map->btf_key_type_id = def->key_type_id; + map->btf_value_type_id = def->value_type_id; + + /* auto-adjust BPF ringbuf map max_entries to be a multiple of page size */ + if (map_is_ringbuf(map)) + map->def.max_entries = adjust_ringbuf_sz(map->def.max_entries); + + if (def->parts & MAP_DEF_MAP_TYPE) + pr_debug("map '%s': found type = %u.\n", map->name, def->map_type); + + if (def->parts & MAP_DEF_KEY_TYPE) + pr_debug("map '%s': found key [%u], sz = %u.\n", + map->name, def->key_type_id, def->key_size); + else if (def->parts & MAP_DEF_KEY_SIZE) + pr_debug("map '%s': found key_size = %u.\n", map->name, def->key_size); + + if (def->parts & MAP_DEF_VALUE_TYPE) + pr_debug("map '%s': found value [%u], sz = %u.\n", + map->name, def->value_type_id, def->value_size); + else if (def->parts & MAP_DEF_VALUE_SIZE) + pr_debug("map '%s': found value_size = %u.\n", map->name, def->value_size); + + if (def->parts & MAP_DEF_MAX_ENTRIES) + pr_debug("map '%s': found max_entries = %u.\n", map->name, def->max_entries); + if (def->parts & MAP_DEF_MAP_FLAGS) + pr_debug("map '%s': found map_flags = 0x%x.\n", map->name, def->map_flags); + if (def->parts & MAP_DEF_MAP_EXTRA) + pr_debug("map '%s': found map_extra = 0x%llx.\n", map->name, + (unsigned long long)def->map_extra); + if (def->parts & MAP_DEF_PINNING) + pr_debug("map '%s': found pinning = %u.\n", map->name, def->pinning); + if (def->parts & MAP_DEF_NUMA_NODE) + pr_debug("map '%s': found numa_node = %u.\n", map->name, def->numa_node); + + if (def->parts & MAP_DEF_INNER_MAP) + pr_debug("map '%s': found inner map definition.\n", map->name); +} + +static const char *btf_var_linkage_str(__u32 linkage) +{ + switch (linkage) { + case BTF_VAR_STATIC: return "static"; + case BTF_VAR_GLOBAL_ALLOCATED: return "global"; + case BTF_VAR_GLOBAL_EXTERN: return "extern"; + default: return "unknown"; + } +} + +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) +{ + struct btf_map_def map_def = {}, inner_def = {}; + 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; + int err; + + 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) { + pr_warn("map '%s': unsupported map linkage %s.\n", + map_name, btf_var_linkage_str(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); + + err = parse_btf_map_def(map->name, obj->btf, def, strict, &map_def, &inner_def); + if (err) + return err; + + fill_map_from_def(map, &map_def); + + if (map_def.pinning == 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; + } + } + + if (map_def.parts & MAP_DEF_INNER_MAP) { + map->inner_map = calloc(1, sizeof(*map->inner_map)); + if (!map->inner_map) + return -ENOMEM; + map->inner_map->fd = -1; + map->inner_map->sec_idx = sec_idx; + 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); + + fill_map_from_def(map->inner_map, &inner_def); + } + + err = map_fill_btf_type_info(obj, map); + if (err) + return err; + + return 0; +} + +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__type_cnt(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 = 0; + + strict = !OPTS_GET(opts, relaxed_maps, false); + pin_root_path = OPTS_GET(opts, pin_root_path, NULL); + + 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); + + return err; +} + +static bool section_have_execinstr(struct bpf_object *obj, int idx) +{ + Elf64_Shdr *sh; + + sh = elf_sec_hdr(obj, elf_sec_by_idx(obj, idx)); + if (!sh) + return false; + + return sh->sh_flags & SHF_EXECINSTR; +} + +static bool btf_needs_sanitization(struct bpf_object *obj) +{ + bool has_func_global = kernel_supports(obj, FEAT_BTF_GLOBAL_FUNC); + bool has_datasec = kernel_supports(obj, FEAT_BTF_DATASEC); + bool has_float = kernel_supports(obj, FEAT_BTF_FLOAT); + bool has_func = kernel_supports(obj, FEAT_BTF_FUNC); + bool has_decl_tag = kernel_supports(obj, FEAT_BTF_DECL_TAG); + bool has_type_tag = kernel_supports(obj, FEAT_BTF_TYPE_TAG); + bool has_enum64 = kernel_supports(obj, FEAT_BTF_ENUM64); + + return !has_func || !has_datasec || !has_func_global || !has_float || + !has_decl_tag || !has_type_tag || !has_enum64; +} + +static int bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) +{ + bool has_func_global = kernel_supports(obj, FEAT_BTF_GLOBAL_FUNC); + bool has_datasec = kernel_supports(obj, FEAT_BTF_DATASEC); + bool has_float = kernel_supports(obj, FEAT_BTF_FLOAT); + bool has_func = kernel_supports(obj, FEAT_BTF_FUNC); + bool has_decl_tag = kernel_supports(obj, FEAT_BTF_DECL_TAG); + bool has_type_tag = kernel_supports(obj, FEAT_BTF_TYPE_TAG); + bool has_enum64 = kernel_supports(obj, FEAT_BTF_ENUM64); + int enum64_placeholder_id = 0; + struct btf_type *t; + int i, j, vlen; + + for (i = 1; i < btf__type_cnt(btf); i++) { + t = (struct btf_type *)btf__type_by_id(btf, i); + + if ((!has_datasec && btf_is_var(t)) || (!has_decl_tag && btf_is_decl_tag(t))) { + /* replace VAR/DECL_TAG 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); + } else if (!has_float && btf_is_float(t)) { + /* replace FLOAT with an equally-sized empty STRUCT; + * since C compilers do not accept e.g. "float" as a + * valid struct name, make it anonymous + */ + t->name_off = 0; + t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 0); + } else if (!has_type_tag && btf_is_type_tag(t)) { + /* replace TYPE_TAG with a CONST */ + t->name_off = 0; + t->info = BTF_INFO_ENC(BTF_KIND_CONST, 0, 0); + } else if (!has_enum64 && btf_is_enum(t)) { + /* clear the kflag */ + t->info = btf_type_info(btf_kind(t), btf_vlen(t), false); + } else if (!has_enum64 && btf_is_enum64(t)) { + /* replace ENUM64 with a union */ + struct btf_member *m; + + if (enum64_placeholder_id == 0) { + enum64_placeholder_id = btf__add_int(btf, "enum64_placeholder", 1, 0); + if (enum64_placeholder_id < 0) + return enum64_placeholder_id; + + t = (struct btf_type *)btf__type_by_id(btf, i); + } + + m = btf_members(t); + vlen = btf_vlen(t); + t->info = BTF_INFO_ENC(BTF_KIND_UNION, 0, vlen); + for (j = 0; j < vlen; j++, m++) { + m->type = enum64_placeholder_id; + m->offset = 0; + } + } + } + + return 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); + err = libbpf_get_error(obj->btf); + if (err) { + 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); + } + if (btf_ext_data) { + struct btf_ext_info *ext_segs[3]; + int seg_num, sec_num; + + 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); + err = libbpf_get_error(obj->btf_ext); + if (err) { + pr_warn("Error loading ELF section %s: %d. Ignored and continue.\n", + BTF_EXT_ELF_SEC, err); + obj->btf_ext = NULL; + goto out; + } + + /* setup .BTF.ext to ELF section mapping */ + ext_segs[0] = &obj->btf_ext->func_info; + ext_segs[1] = &obj->btf_ext->line_info; + ext_segs[2] = &obj->btf_ext->core_relo_info; + for (seg_num = 0; seg_num < ARRAY_SIZE(ext_segs); seg_num++) { + struct btf_ext_info *seg = ext_segs[seg_num]; + const struct btf_ext_info_sec *sec; + const char *sec_name; + Elf_Scn *scn; + + if (seg->sec_cnt == 0) + continue; + + seg->sec_idxs = calloc(seg->sec_cnt, sizeof(*seg->sec_idxs)); + if (!seg->sec_idxs) { + err = -ENOMEM; + goto out; + } + + sec_num = 0; + for_each_btf_ext_sec(seg, sec) { + /* preventively increment index to avoid doing + * this before every continue below + */ + sec_num++; + + sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off); + if (str_is_empty(sec_name)) + continue; + scn = elf_sec_by_name(obj, sec_name); + if (!scn) + continue; + + seg->sec_idxs[sec_num - 1] = elf_ndxscn(scn); + } + } + } +out: + if (err && libbpf_needs_btf(obj)) { + pr_warn("BTF is required, but is missing or corrupted.\n"); + return err; + } + return 0; +} + +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, i, vars = btf_vlen(t); + const char *sec_name = btf__name_by_offset(btf, t->name_off); + struct btf_var_secinfo *vsi; + bool fixup_offsets = false; + int err; + + if (!sec_name) { + pr_debug("No name found in string section for DATASEC kind.\n"); + return -ENOENT; + } + + /* Extern-backing datasecs (.ksyms, .kconfig) have their size and + * variable offsets set at the previous step. Further, not every + * extern BTF VAR has corresponding ELF symbol preserved, so we skip + * all fixups altogether for such sections and go straight to sorting + * VARs within their DATASEC. + */ + if (strcmp(sec_name, KCONFIG_SEC) == 0 || strcmp(sec_name, KSYMS_SEC) == 0) + goto sort_vars; + + /* Clang leaves DATASEC size and VAR offsets as zeroes, so we need to + * fix this up. But BPF static linker already fixes this up and fills + * all the sizes and offsets during static linking. So this step has + * to be optional. But the STV_HIDDEN handling is non-optional for any + * non-extern DATASEC, so the variable fixup loop below handles both + * functions at the same time, paying the cost of BTF VAR <-> ELF + * symbol matching just once. + */ + if (t->size == 0) { + err = find_elf_sec_sz(obj, sec_name, &size); + if (err || !size) { + pr_debug("sec '%s': failed to determine size from ELF: size %u, err %d\n", + sec_name, size, err); + return -ENOENT; + } + + t->size = size; + fixup_offsets = true; + } + + for (i = 0, vsi = btf_var_secinfos(t); i < vars; i++, vsi++) { + const struct btf_type *t_var; + struct btf_var *var; + const char *var_name; + Elf64_Sym *sym; + + t_var = btf__type_by_id(btf, vsi->type); + if (!t_var || !btf_is_var(t_var)) { + pr_debug("sec '%s': unexpected non-VAR type found\n", sec_name); + return -EINVAL; + } + + var = btf_var(t_var); + if (var->linkage == BTF_VAR_STATIC || var->linkage == BTF_VAR_GLOBAL_EXTERN) + continue; + + var_name = btf__name_by_offset(btf, t_var->name_off); + if (!var_name) { + pr_debug("sec '%s': failed to find name of DATASEC's member #%d\n", + sec_name, i); + return -ENOENT; + } + + sym = find_elf_var_sym(obj, var_name); + if (IS_ERR(sym)) { + pr_debug("sec '%s': failed to find ELF symbol for VAR '%s'\n", + sec_name, var_name); + return -ENOENT; + } + + if (fixup_offsets) + vsi->offset = sym->st_value; + + /* if variable is a global/weak symbol, but has restricted + * (STV_HIDDEN or STV_INTERNAL) visibility, mark its BTF VAR + * as static. This follows similar logic for functions (BPF + * subprogs) and influences libbpf's further decisions about + * whether to make global data BPF array maps as + * BPF_F_MMAPABLE. + */ + if (ELF64_ST_VISIBILITY(sym->st_other) == STV_HIDDEN + || ELF64_ST_VISIBILITY(sym->st_other) == STV_INTERNAL) + var->linkage = BTF_VAR_STATIC; + } + +sort_vars: + qsort(btf_var_secinfos(t), vars, sizeof(*vsi), compare_vsi_off); + return 0; +} + +static int bpf_object_fixup_btf(struct bpf_object *obj) +{ + int i, n, err = 0; + + if (!obj->btf) + return 0; + + n = btf__type_cnt(obj->btf); + for (i = 1; i < n; i++) { + struct btf_type *t = btf_type_by_id(obj->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, obj->btf, t); + if (err) + return err; + } + } + + return 0; +} + +static bool 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 bool obj_needs_vmlinux_btf(const struct bpf_object *obj) +{ + struct bpf_program *prog; + int i; + + /* CO-RE relocations need kernel BTF, only when btf_custom_path + * is not specified + */ + if (obj->btf_ext && obj->btf_ext->core_relo_info.len && !obj->btf_custom_path) + return 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) + return true; + } + + bpf_object__for_each_program(prog, obj) { + if (!prog->autoload) + continue; + if (prog_needs_vmlinux_btf(prog)) + return true; + } + + return false; +} + +static int bpf_object__load_vmlinux_btf(struct bpf_object *obj, bool force) +{ + int err; + + /* btf_vmlinux could be loaded earlier */ + if (obj->btf_vmlinux || obj->gen_loader) + return 0; + + if (!force && !obj_needs_vmlinux_btf(obj)) + return 0; + + obj->btf_vmlinux = btf__load_vmlinux_btf(); + err = libbpf_get_error(obj->btf_vmlinux); + if (err) { + 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 i, err = 0; + + if (!obj->btf) + return 0; + + if (!kernel_supports(obj, FEAT_BTF)) { + if (kernel_needs_btf(obj)) { + err = -EOPNOTSUPP; + goto report; + } + pr_debug("Kernel doesn't support BTF, skipping uploading it.\n"); + return 0; + } + + /* Even though some subprogs are global/weak, user might prefer more + * permissive BPF verification process that BPF verifier performs for + * static functions, taking into account more context from the caller + * functions. In such case, they need to mark such subprogs with + * __attribute__((visibility("hidden"))) and libbpf will adjust + * corresponding FUNC BTF type to be marked as static and trigger more + * involved BPF verification process. + */ + for (i = 0; i < obj->nr_programs; i++) { + struct bpf_program *prog = &obj->programs[i]; + struct btf_type *t; + const char *name; + int j, n; + + if (!prog->mark_btf_static || !prog_is_subprog(obj, prog)) + continue; + + n = btf__type_cnt(obj->btf); + for (j = 1; j < n; j++) { + t = btf_type_by_id(obj->btf, j); + if (!btf_is_func(t) || btf_func_linkage(t) != BTF_FUNC_GLOBAL) + continue; + + name = btf__str_by_offset(obj->btf, t->name_off); + if (strcmp(name, prog->name) != 0) + continue; + + t->info = btf_type_info(BTF_KIND_FUNC, BTF_FUNC_STATIC, 0); + break; + } + } + + 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__raw_data(obj->btf, &sz); + kern_btf = btf__new(raw_data, sz); + err = libbpf_get_error(kern_btf); + if (err) + return err; + + /* enforce 8-byte pointers for BPF-targeted BTFs */ + btf__set_pointer_size(obj->btf, 8); + err = bpf_object__sanitize_btf(obj, kern_btf); + if (err) + return err; + } + + if (obj->gen_loader) { + __u32 raw_size = 0; + const void *raw_data = btf__raw_data(kern_btf, &raw_size); + + if (!raw_data) + return -ENOMEM; + bpf_gen__load_btf(obj->gen_loader, raw_data, raw_size); + /* Pretend to have valid FD to pass various fd >= 0 checks. + * This fd == 0 will not be used with any syscall and will be reset to -1 eventually. + */ + btf__set_fd(kern_btf, 0); + } else { + /* currently BPF_BTF_LOAD only supports log_level 1 */ + err = btf_load_into_kernel(kern_btf, obj->log_buf, obj->log_size, + obj->log_level ? 1 : 0); + } + 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 Elf64_Shdr *elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn) +{ + Elf64_Shdr *shdr; + + if (!scn) + return NULL; + + shdr = elf64_getshdr(scn); + if (!shdr) { + pr_warn("elf: failed to get section(%zu) header from %s: %s\n", + elf_ndxscn(scn), obj->path, elf_errmsg(-1)); + return NULL; + } + + return shdr; +} + +static const char *elf_sec_name(const struct bpf_object *obj, Elf_Scn *scn) +{ + const char *name; + Elf64_Shdr *sh; + + if (!scn) + return NULL; + + sh = elf_sec_hdr(obj, scn); + if (!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 Elf64_Sym *elf_sym_by_idx(const struct bpf_object *obj, size_t idx) +{ + if (idx >= obj->efile.symbols->d_size / sizeof(Elf64_Sym)) + return NULL; + + return (Elf64_Sym *)obj->efile.symbols->d_buf + idx; +} + +static Elf64_Rel *elf_rel_by_idx(Elf_Data *data, size_t idx) +{ + if (idx >= data->d_size / sizeof(Elf64_Rel)) + return NULL; + + return (Elf64_Rel *)data->d_buf + idx; +} + +static bool is_sec_name_dwarf(const char *name) +{ + /* approximation, but the actual list is too long */ + return str_has_pfx(name, ".debug_"); +} + +static bool ignore_elf_section(Elf64_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 == 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 (str_has_pfx(name, ".rel")) { + 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) +{ + struct elf_sec_desc *sec_desc; + 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; + Elf64_Shdr *sh; + + /* ELF section indices are 0-based, but sec #0 is special "invalid" + * section. Since section count retrieved by elf_getshdrnum() does + * include sec #0, it is already the necessary size of an array to keep + * all the sections. + */ + if (elf_getshdrnum(obj->efile.elf, &obj->efile.sec_cnt)) { + pr_warn("elf: failed to get the number of sections for %s: %s\n", + obj->path, elf_errmsg(-1)); + return -LIBBPF_ERRNO__FORMAT; + } + obj->efile.secs = calloc(obj->efile.sec_cnt, sizeof(*obj->efile.secs)); + if (!obj->efile.secs) + return -ENOMEM; + + /* 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) { + sh = elf_sec_hdr(obj, scn); + if (!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; + + idx = elf_ndxscn(scn); + + obj->efile.symbols = data; + obj->efile.symbols_shndx = idx; + obj->efile.strtabidx = sh->sh_link; + } + } + + if (!obj->efile.symbols) { + pr_warn("elf: couldn't find symbol table in %s, stripped object file?\n", + obj->path); + return -ENOENT; + } + + scn = NULL; + while ((scn = elf_nextscn(elf, scn)) != NULL) { + idx = elf_ndxscn(scn); + sec_desc = &obj->efile.secs[idx]; + + sh = elf_sec_hdr(obj, scn); + if (!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) { + pr_warn("elf: legacy map definitions in 'maps' section are not supported by libbpf v1.0+\n"); + return -ENOTSUP; + } else if (strcmp(name, MAPS_ELF_SEC) == 0) { + obj->efile.btf_maps_shndx = idx; + } else if (strcmp(name, BTF_ELF_SEC) == 0) { + if (sh->sh_type != SHT_PROGBITS) + return -LIBBPF_ERRNO__FORMAT; + btf_data = data; + } else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) { + if (sh->sh_type != SHT_PROGBITS) + return -LIBBPF_ERRNO__FORMAT; + 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 || + str_has_pfx(name, DATA_SEC ".")) { + sec_desc->sec_type = SEC_DATA; + sec_desc->shdr = sh; + sec_desc->data = data; + } else if (strcmp(name, RODATA_SEC) == 0 || + str_has_pfx(name, RODATA_SEC ".")) { + sec_desc->sec_type = SEC_RODATA; + sec_desc->shdr = sh; + sec_desc->data = data; + } 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 targ_sec_idx = sh->sh_info; /* points to other section */ + + if (sh->sh_entsize != sizeof(Elf64_Rel) || + targ_sec_idx >= obj->efile.sec_cnt) + return -LIBBPF_ERRNO__FORMAT; + + /* Only do relo for section with exec instructions */ + if (!section_have_execinstr(obj, targ_sec_idx) && + 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, targ_sec_idx, + elf_sec_name(obj, elf_sec_by_idx(obj, targ_sec_idx)) ?: "<?>"); + continue; + } + + sec_desc->sec_type = SEC_RELO; + sec_desc->shdr = sh; + sec_desc->data = data; + } else if (sh->sh_type == SHT_NOBITS && (strcmp(name, BSS_SEC) == 0 || + str_has_pfx(name, BSS_SEC "."))) { + sec_desc->sec_type = SEC_BSS; + sec_desc->shdr = sh; + sec_desc->data = data; + } 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 + */ + if (obj->nr_programs) + 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 Elf64_Sym *sym) +{ + int bind = ELF64_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) && + ELF64_ST_TYPE(sym->st_info) == STT_NOTYPE; +} + +static bool sym_is_subprog(const Elf64_Sym *sym, int text_shndx) +{ + int bind = ELF64_ST_BIND(sym->st_info); + int type = ELF64_ST_TYPE(sym->st_info); + + /* in .text section */ + if (sym->st_shndx != text_shndx) + return false; + + /* local function */ + if (bind == STB_LOCAL && type == STT_SECTION) + return true; + + /* global function */ + return bind == STB_GLOBAL && type == STT_FUNC; +} + +static int find_extern_btf_id(const struct btf *btf, const char *ext_name) +{ + const struct btf_type *t; + const char *tname; + int i, n; + + if (!btf) + return -ESRCH; + + n = btf__type_cnt(btf); + for (i = 1; i < n; i++) { + t = btf__type_by_id(btf, i); + + if (!btf_is_var(t) && !btf_is_func(t)) + continue; + + tname = btf__name_by_offset(btf, t->name_off); + if (strcmp(tname, ext_name)) + continue; + + if (btf_is_var(t) && + btf_var(t)->linkage != BTF_VAR_GLOBAL_EXTERN) + return -EINVAL; + + if (btf_is_func(t) && btf_func_linkage(t) != BTF_FUNC_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__type_cnt(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_ENUM64: + 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__type_cnt(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 add_dummy_ksym_var(struct btf *btf) +{ + int i, int_btf_id, sec_btf_id, dummy_var_btf_id; + const struct btf_var_secinfo *vs; + const struct btf_type *sec; + + if (!btf) + return 0; + + sec_btf_id = btf__find_by_name_kind(btf, KSYMS_SEC, + BTF_KIND_DATASEC); + if (sec_btf_id < 0) + return 0; + + sec = btf__type_by_id(btf, sec_btf_id); + vs = btf_var_secinfos(sec); + for (i = 0; i < btf_vlen(sec); i++, vs++) { + const struct btf_type *vt; + + vt = btf__type_by_id(btf, vs->type); + if (btf_is_func(vt)) + break; + } + + /* No func in ksyms sec. No need to add dummy var. */ + if (i == btf_vlen(sec)) + return 0; + + int_btf_id = find_int_btf_id(btf); + dummy_var_btf_id = btf__add_var(btf, + "dummy_ksym", + BTF_VAR_GLOBAL_ALLOCATED, + int_btf_id); + if (dummy_var_btf_id < 0) + pr_warn("cannot create a dummy_ksym var\n"); + + return dummy_var_btf_id; +} + +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, dummy_var_btf_id; + const char *ext_name, *sec_name; + Elf_Scn *scn; + Elf64_Shdr *sh; + + if (!obj->efile.symbols) + return 0; + + scn = elf_sec_by_idx(obj, obj->efile.symbols_shndx); + sh = elf_sec_hdr(obj, scn); + if (!sh || sh->sh_entsize != sizeof(Elf64_Sym)) + return -LIBBPF_ERRNO__FORMAT; + + dummy_var_btf_id = add_dummy_ksym_var(obj->btf); + if (dummy_var_btf_id < 0) + return dummy_var_btf_id; + + n = sh->sh_size / sh->sh_entsize; + pr_debug("looking for externs among %d symbols...\n", n); + + for (i = 0; i < n; i++) { + Elf64_Sym *sym = elf_sym_by_idx(obj, i); + + if (!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 = ELF64_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) { + if (btf_is_func(t)) { + pr_warn("extern function %s is unsupported under %s section\n", + ext->name, KCONFIG_SEC); + return -ENOTSUP; + } + 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 extern function, a dummy_var added earlier + * will be used to replace the vs->type and + * its name string will be used to refill + * the missing param's name. + */ + const struct btf_type *dummy_var; + + dummy_var = btf__type_by_id(obj->btf, dummy_var_btf_id); + 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 %s '%s'\n", + btf_kind_str(vt), ext_name); + return -ESRCH; + } + if (btf_is_func(vt)) { + const struct btf_type *func_proto; + struct btf_param *param; + int j; + + func_proto = btf__type_by_id(obj->btf, + vt->type); + param = btf_params(func_proto); + /* Reuse the dummy_var string if the + * func proto does not have param name. + */ + for (j = 0; j < btf_vlen(func_proto); j++) + if (param[j].type && !param[j].name_off) + param[j].name_off = + dummy_var->name_off; + vs->type = dummy_var_btf_id; + vt->info &= ~0xffff; + vt->info |= BTF_FUNC_GLOBAL; + } else { + 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; +} + +static bool prog_is_subprog(const struct bpf_object *obj, const struct bpf_program *prog) +{ + 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 errno = ENOENT, NULL; +} + +static bool bpf_object__shndx_is_data(const struct bpf_object *obj, + int shndx) +{ + switch (obj->efile.secs[shndx].sec_type) { + case SEC_BSS: + case SEC_DATA: + case SEC_RODATA: + return true; + default: + return false; + } +} + +static bool bpf_object__shndx_is_maps(const struct bpf_object *obj, + int shndx) +{ + return 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.symbols_shndx) + return LIBBPF_MAP_KCONFIG; + + switch (obj->efile.secs[shndx].sec_type) { + case SEC_BSS: + return LIBBPF_MAP_BSS; + case SEC_DATA: + return LIBBPF_MAP_DATA; + case SEC_RODATA: + return LIBBPF_MAP_RODATA; + default: + 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 Elf64_Sym *sym, const Elf64_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; + + if (!is_call_insn(insn) && !is_ldimm64_insn(insn)) { + 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 = ELF64_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); + if (insn->code == (BPF_JMP | BPF_CALL)) + reloc_desc->type = RELO_EXTERN_FUNC; + else + reloc_desc->type = RELO_EXTERN_VAR; + reloc_desc->insn_idx = insn_idx; + reloc_desc->sym_off = i; /* sym_off stores extern index */ + return 0; + } + + /* sub-program call relocation */ + if (is_call_insn(insn)) { + 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 (!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; + } + + /* loading subprog addresses */ + if (sym_is_subprog(sym, obj->efile.text_shndx)) { + /* global_func: sym->st_value = offset in the section, insn->imm = 0. + * local_func: sym->st_value = 0, insn->imm = offset in the section. + */ + if ((sym->st_value % BPF_INSN_SZ) || (insn->imm % BPF_INSN_SZ)) { + pr_warn("prog '%s': bad subprog addr relo against '%s' at offset %zu+%d\n", + prog->name, sym_name, (size_t)sym->st_value, insn->imm); + return -LIBBPF_ERRNO__RELOC; + } + + reloc_desc->type = RELO_SUBPROG_ADDR; + reloc_desc->insn_idx = insn_idx; + reloc_desc->sym_off = sym->st_value; + return 0; + } + + 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 || map->sec_idx != sym->st_shndx) + 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, Elf64_Shdr *shdr, Elf_Data *data) +{ + const char *relo_sec_name, *sec_name; + size_t sec_idx = shdr->sh_info, sym_idx; + struct bpf_program *prog; + struct reloc_desc *relos; + int err, i, nrels; + const char *sym_name; + __u32 insn_idx; + Elf_Scn *scn; + Elf_Data *scn_data; + Elf64_Sym *sym; + Elf64_Rel *rel; + + if (sec_idx >= obj->efile.sec_cnt) + return -EINVAL; + + scn = elf_sec_by_idx(obj, sec_idx); + scn_data = elf_sec_data(obj, scn); + + relo_sec_name = elf_sec_str(obj, shdr->sh_name); + sec_name = elf_sec_name(obj, scn); + 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++) { + rel = elf_rel_by_idx(data, i); + if (!rel) { + pr_warn("sec '%s': failed to get relo #%d\n", relo_sec_name, i); + return -LIBBPF_ERRNO__FORMAT; + } + + sym_idx = ELF64_R_SYM(rel->r_info); + sym = elf_sym_by_idx(obj, sym_idx); + if (!sym) { + pr_warn("sec '%s': symbol #%zu not found for relo #%d\n", + relo_sec_name, sym_idx, i); + return -LIBBPF_ERRNO__FORMAT; + } + + if (sym->st_shndx >= obj->efile.sec_cnt) { + pr_warn("sec '%s': corrupted symbol #%zu pointing to invalid section #%zu for relo #%d\n", + relo_sec_name, sym_idx, (size_t)sym->st_shndx, i); + return -LIBBPF_ERRNO__FORMAT; + } + + if (rel->r_offset % BPF_INSN_SZ || rel->r_offset >= scn_data->d_size) { + pr_warn("sec '%s': invalid offset 0x%zx for relo #%d\n", + relo_sec_name, (size_t)rel->r_offset, 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 (ELF64_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_debug("sec '%s': relo #%d: couldn't find program in section '%s' for insn #%u, probably overridden weak function, skipping...\n", + relo_sec_name, i, sec_name, insn_idx); + continue; + } + + 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 map_fill_btf_type_info(struct bpf_object *obj, struct bpf_map *map) +{ + int id; + + if (!obj->btf) + return -ENOENT; + + /* 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; + + /* + * LLVM annotates global data differently in BTF, that is, + * only as '.data', '.bss' or '.rodata'. + */ + if (!bpf_map__is_internal(map)) + return -ENOENT; + + id = btf__find_by_name(obj->btf, map->real_name); + if (id < 0) + return id; + + map->btf_key_type_id = 0; + map->btf_value_type_id = 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; +} + +bool bpf_map__autocreate(const struct bpf_map *map) +{ + return map->autocreate; +} + +int bpf_map__set_autocreate(struct bpf_map *map, bool autocreate) +{ + if (map->obj->loaded) + return libbpf_err(-EBUSY); + + map->autocreate = autocreate; + 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; + + memset(&info, 0, len); + 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 libbpf_err(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 libbpf_err(-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; + map->map_extra = info.map_extra; + + return 0; + +err_close_new_fd: + close(new_fd); +err_free_new_name: + free(new_name); + return libbpf_err(err); +} + +__u32 bpf_map__max_entries(const struct bpf_map *map) +{ + return map->def.max_entries; +} + +struct bpf_map *bpf_map__inner_map(struct bpf_map *map) +{ + if (!bpf_map_type__is_map_in_map(map->def.type)) + return errno = EINVAL, NULL; + + return map->inner_map; +} + +int bpf_map__set_max_entries(struct bpf_map *map, __u32 max_entries) +{ + if (map->obj->loaded) + return libbpf_err(-EBUSY); + + map->def.max_entries = max_entries; + + /* auto-adjust BPF ringbuf map max_entries to be a multiple of page size */ + if (map_is_ringbuf(map)) + map->def.max_entries = adjust_ringbuf_sz(map->def.max_entries); + + return 0; +} + +static int +bpf_object__probe_loading(struct bpf_object *obj) +{ + char *cp, errmsg[STRERR_BUFSIZE]; + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + int ret, insn_cnt = ARRAY_SIZE(insns); + + if (obj->gen_loader) + return 0; + + ret = bump_rlimit_memlock(); + if (ret) + pr_warn("Failed to bump RLIMIT_MEMLOCK (err = %d), you might need to do it explicitly!\n", ret); + + /* make sure basic loading works */ + ret = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", insns, insn_cnt, NULL); + if (ret < 0) + ret = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL", insns, insn_cnt, NULL); + 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) +{ + const size_t attr_sz = offsetofend(union bpf_attr, prog_name); + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + union bpf_attr attr; + int ret; + + memset(&attr, 0, attr_sz); + attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER; + attr.license = ptr_to_u64("GPL"); + attr.insns = ptr_to_u64(insns); + attr.insn_cnt = (__u32)ARRAY_SIZE(insns); + libbpf_strlcpy(attr.prog_name, "libbpf_nametest", sizeof(attr.prog_name)); + + /* make sure loading with name works */ + ret = sys_bpf_prog_load(&attr, attr_sz, PROG_LOAD_ATTEMPTS); + return probe_fd(ret); +} + +static int probe_kern_global_data(void) +{ + 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, insn_cnt = ARRAY_SIZE(insns); + + map = bpf_map_create(BPF_MAP_TYPE_ARRAY, "libbpf_global", sizeof(int), 32, 1, NULL); + 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; + + ret = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", insns, insn_cnt, NULL); + 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_btf_float(void) +{ + static const char strs[] = "\0float"; + __u32 types[] = { + /* float */ + BTF_TYPE_FLOAT_ENC(1, 4), + }; + + return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), + strs, sizeof(strs))); +} + +static int probe_kern_btf_decl_tag(void) +{ + static const char strs[] = "\0tag"; + __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, + /* attr */ + BTF_TYPE_DECL_TAG_ENC(1, 2, -1), + }; + + return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), + strs, sizeof(strs))); +} + +static int probe_kern_btf_type_tag(void) +{ + static const char strs[] = "\0tag"; + __u32 types[] = { + /* int */ + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + /* attr */ + BTF_TYPE_TYPE_TAG_ENC(1, 1), /* [2] */ + /* ptr */ + BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 2), /* [3] */ + }; + + return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), + strs, sizeof(strs))); +} + +static int probe_kern_array_mmap(void) +{ + LIBBPF_OPTS(bpf_map_create_opts, opts, .map_flags = BPF_F_MMAPABLE); + int fd; + + fd = bpf_map_create(BPF_MAP_TYPE_ARRAY, "libbpf_mmap", sizeof(int), sizeof(int), 1, &opts); + return probe_fd(fd); +} + +static int probe_kern_exp_attach_type(void) +{ + LIBBPF_OPTS(bpf_prog_load_opts, opts, .expected_attach_type = BPF_CGROUP_INET_SOCK_CREATE); + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + int fd, insn_cnt = ARRAY_SIZE(insns); + + /* 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 + */ + fd = bpf_prog_load(BPF_PROG_TYPE_CGROUP_SOCK, NULL, "GPL", insns, insn_cnt, &opts); + return probe_fd(fd); +} + +static int probe_kern_probe_read_kernel(void) +{ + 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(), + }; + int fd, insn_cnt = ARRAY_SIZE(insns); + + fd = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL", insns, insn_cnt, NULL); + return probe_fd(fd); +} + +static int probe_prog_bind_map(void) +{ + char *cp, errmsg[STRERR_BUFSIZE]; + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + int ret, map, prog, insn_cnt = ARRAY_SIZE(insns); + + map = bpf_map_create(BPF_MAP_TYPE_ARRAY, "libbpf_det_bind", sizeof(int), 32, 1, NULL); + 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; + } + + prog = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", insns, insn_cnt, NULL); + if (prog < 0) { + close(map); + return 0; + } + + ret = bpf_prog_bind_map(prog, map, NULL); + + close(map); + close(prog); + + return ret >= 0; +} + +static int probe_module_btf(void) +{ + static const char strs[] = "\0int"; + __u32 types[] = { + /* int */ + BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), + }; + struct bpf_btf_info info; + __u32 len = sizeof(info); + char name[16]; + int fd, err; + + fd = libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs)); + if (fd < 0) + return 0; /* BTF not supported at all */ + + memset(&info, 0, sizeof(info)); + info.name = ptr_to_u64(name); + info.name_len = sizeof(name); + + /* check that BPF_OBJ_GET_INFO_BY_FD supports specifying name pointer; + * kernel's module BTF support coincides with support for + * name/name_len fields in struct bpf_btf_info. + */ + err = bpf_obj_get_info_by_fd(fd, &info, &len); + close(fd); + return !err; +} + +static int probe_perf_link(void) +{ + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + int prog_fd, link_fd, err; + + prog_fd = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL", + insns, ARRAY_SIZE(insns), NULL); + if (prog_fd < 0) + return -errno; + + /* use invalid perf_event FD to get EBADF, if link is supported; + * otherwise EINVAL should be returned + */ + link_fd = bpf_link_create(prog_fd, -1, BPF_PERF_EVENT, NULL); + err = -errno; /* close() can clobber errno */ + + if (link_fd >= 0) + close(link_fd); + close(prog_fd); + + return link_fd < 0 && err == -EBADF; +} + +static int probe_kern_bpf_cookie(void) +{ + struct bpf_insn insns[] = { + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_attach_cookie), + BPF_EXIT_INSN(), + }; + int ret, insn_cnt = ARRAY_SIZE(insns); + + ret = bpf_prog_load(BPF_PROG_TYPE_KPROBE, NULL, "GPL", insns, insn_cnt, NULL); + return probe_fd(ret); +} + +static int probe_kern_btf_enum64(void) +{ + static const char strs[] = "\0enum64"; + __u32 types[] = { + BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_ENUM64, 0, 0), 8), + }; + + return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), + strs, sizeof(strs))); +} + +static int probe_kern_syscall_wrapper(void); + +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, + }, + [FEAT_MODULE_BTF] = { + "module BTF support", probe_module_btf, + }, + [FEAT_BTF_FLOAT] = { + "BTF_KIND_FLOAT support", probe_kern_btf_float, + }, + [FEAT_PERF_LINK] = { + "BPF perf link support", probe_perf_link, + }, + [FEAT_BTF_DECL_TAG] = { + "BTF_KIND_DECL_TAG support", probe_kern_btf_decl_tag, + }, + [FEAT_BTF_TYPE_TAG] = { + "BTF_KIND_TYPE_TAG support", probe_kern_btf_type_tag, + }, + [FEAT_MEMCG_ACCOUNT] = { + "memcg-based memory accounting", probe_memcg_account, + }, + [FEAT_BPF_COOKIE] = { + "BPF cookie support", probe_kern_bpf_cookie, + }, + [FEAT_BTF_ENUM64] = { + "BTF_KIND_ENUM64 support", probe_kern_btf_enum64, + }, + [FEAT_SYSCALL_WRAPPER] = { + "Kernel using syscall wrapper", probe_kern_syscall_wrapper, + }, +}; + +bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id) +{ + struct kern_feature_desc *feat = &feature_probes[feat_id]; + int ret; + + if (obj && obj->gen_loader) + /* To generate loader program assume the latest kernel + * to avoid doing extra prog_load, map_create syscalls. + */ + return true; + + 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 = sizeof(map_info); + int err; + + memset(&map_info, 0, map_info_len); + 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 && + map_info.map_extra == map->map_extra); +} + +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); + close(pin_fd); + if (err) + 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; + + if (obj->gen_loader) { + bpf_gen__map_update_elem(obj->gen_loader, map - obj->maps, + map->mmaped, map->def.value_size); + if (map_type == LIBBPF_MAP_RODATA || map_type == LIBBPF_MAP_KCONFIG) + bpf_gen__map_freeze(obj->gen_loader, map - obj->maps); + return 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, bool is_inner) +{ + LIBBPF_OPTS(bpf_map_create_opts, create_attr); + struct bpf_map_def *def = &map->def; + const char *map_name = NULL; + int err = 0; + + if (kernel_supports(obj, FEAT_PROG_NAME)) + map_name = map->name; + create_attr.map_ifindex = map->map_ifindex; + create_attr.map_flags = def->map_flags; + create_attr.numa_node = map->numa_node; + create_attr.map_extra = map->map_extra; + + if (bpf_map__is_struct_ops(map)) + create_attr.btf_vmlinux_value_type_id = map->btf_vmlinux_value_type_id; + + if (obj->btf && btf__fd(obj->btf) >= 0) { + 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, true); + 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; + } + + switch (def->type) { + case BPF_MAP_TYPE_PERF_EVENT_ARRAY: + case BPF_MAP_TYPE_CGROUP_ARRAY: + case BPF_MAP_TYPE_STACK_TRACE: + 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_CPUMAP: + case BPF_MAP_TYPE_XSKMAP: + case BPF_MAP_TYPE_SOCKMAP: + case BPF_MAP_TYPE_SOCKHASH: + case BPF_MAP_TYPE_QUEUE: + case BPF_MAP_TYPE_STACK: + 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; + default: + break; + } + + if (obj->gen_loader) { + bpf_gen__map_create(obj->gen_loader, def->type, map_name, + def->key_size, def->value_size, def->max_entries, + &create_attr, is_inner ? -1 : map - obj->maps); + /* Pretend to have valid FD to pass various fd >= 0 checks. + * This fd == 0 will not be used with any syscall and will be reset to -1 eventually. + */ + map->fd = 0; + } else { + map->fd = bpf_map_create(def->type, map_name, + def->key_size, def->value_size, + def->max_entries, &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_map_create(def->type, map_name, + def->key_size, def->value_size, + def->max_entries, &create_attr); + } + + err = map->fd < 0 ? -errno : 0; + + if (bpf_map_type__is_map_in_map(def->type) && map->inner_map) { + if (obj->gen_loader) + map->inner_map->fd = -1; + bpf_map__destroy(map->inner_map); + zfree(&map->inner_map); + } + + return err; +} + +static int init_map_in_map_slots(struct bpf_object *obj, struct bpf_map *map) +{ + const struct bpf_map *targ_map; + unsigned int i; + int fd, err = 0; + + 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); + + if (obj->gen_loader) { + bpf_gen__populate_outer_map(obj->gen_loader, + map - obj->maps, i, + targ_map - obj->maps); + } else { + 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 init_prog_array_slots(struct bpf_object *obj, struct bpf_map *map) +{ + const struct bpf_program *targ_prog; + unsigned int i; + int fd, err; + + if (obj->gen_loader) + return -ENOTSUP; + + for (i = 0; i < map->init_slots_sz; i++) { + if (!map->init_slots[i]) + continue; + + targ_prog = map->init_slots[i]; + fd = bpf_program__fd(targ_prog); + + err = bpf_map_update_elem(map->fd, &i, &fd, 0); + if (err) { + err = -errno; + pr_warn("map '%s': failed to initialize slot [%d] to prog '%s' fd=%d: %d\n", + map->name, i, targ_prog->name, fd, err); + return err; + } + pr_debug("map '%s': slot [%d] set to prog '%s' fd=%d\n", + map->name, i, targ_prog->name, fd); + } + + zfree(&map->init_slots); + map->init_slots_sz = 0; + + return 0; +} + +static int bpf_object_init_prog_arrays(struct bpf_object *obj) +{ + struct bpf_map *map; + int i, err; + + for (i = 0; i < obj->nr_maps; i++) { + map = &obj->maps[i]; + + if (!map->init_slots_sz || map->def.type != BPF_MAP_TYPE_PROG_ARRAY) + continue; + + err = init_prog_array_slots(obj, map); + if (err < 0) { + zclose(map->fd); + return err; + } + } + return 0; +} + +static int map_set_def_max_entries(struct bpf_map *map) +{ + if (map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && !map->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); + map->def.max_entries = nr_cpus; + } + + 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]; + + /* To support old kernels, we skip creating global data maps + * (.rodata, .data, .kconfig, etc); later on, during program + * loading, if we detect that at least one of the to-be-loaded + * programs is referencing any global data map, we'll error + * out with program name and relocation index logged. + * This approach allows to accommodate Clang emitting + * unnecessary .rodata.str1.1 sections for string literals, + * but also it allows to have CO-RE applications that use + * global variables in some of BPF programs, but not others. + * If those global variable-using programs are not loaded at + * runtime due to bpf_program__set_autoload(prog, false), + * bpf_object loading will succeed just fine even on old + * kernels. + */ + if (bpf_map__is_internal(map) && !kernel_supports(obj, FEAT_GLOBAL_DATA)) + map->autocreate = false; + + if (!map->autocreate) { + pr_debug("map '%s': skipped auto-creating...\n", map->name); + continue; + } + + err = map_set_def_max_entries(map); + if (err) + goto err_out; + + 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, false); + 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 && map->def.type != BPF_MAP_TYPE_PROG_ARRAY) { + err = init_map_in_map_slots(obj, 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; +} + +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. + */ +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; +} + +void bpf_core_free_cands(struct bpf_core_cand_list *cands) +{ + if (!cands) + return; + + free(cands->cands); + free(cands); +} + +int bpf_core_add_cands(struct bpf_core_cand *local_cand, + size_t local_essent_len, + const struct btf *targ_btf, + const char *targ_btf_name, + int targ_start_id, + struct bpf_core_cand_list *cands) +{ + struct bpf_core_cand *new_cands, *cand; + const struct btf_type *t, *local_t; + const char *targ_name, *local_name; + size_t targ_essent_len; + int n, i; + + local_t = btf__type_by_id(local_cand->btf, local_cand->id); + local_name = btf__str_by_offset(local_cand->btf, local_t->name_off); + + n = btf__type_cnt(targ_btf); + for (i = targ_start_id; i < n; i++) { + t = btf__type_by_id(targ_btf, i); + if (!btf_kind_core_compat(t, 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) + continue; + + pr_debug("CO-RE relocating [%d] %s %s: found target candidate [%d] %s %s in [%s]\n", + local_cand->id, btf_kind_str(local_t), + local_name, i, btf_kind_str(t), targ_name, + targ_btf_name); + new_cands = libbpf_reallocarray(cands->cands, cands->len + 1, + sizeof(*cands->cands)); + if (!new_cands) + return -ENOMEM; + + cand = &new_cands[cands->len]; + cand->btf = targ_btf; + cand->id = i; + + cands->cands = new_cands; + cands->len++; + } + return 0; +} + +static int load_module_btfs(struct bpf_object *obj) +{ + struct bpf_btf_info info; + struct module_btf *mod_btf; + struct btf *btf; + char name[64]; + __u32 id = 0, len; + int err, fd; + + if (obj->btf_modules_loaded) + return 0; + + if (obj->gen_loader) + return 0; + + /* don't do this again, even if we find no module BTFs */ + obj->btf_modules_loaded = true; + + /* kernel too old to support module BTFs */ + if (!kernel_supports(obj, FEAT_MODULE_BTF)) + return 0; + + while (true) { + err = bpf_btf_get_next_id(id, &id); + if (err && errno == ENOENT) + return 0; + if (err) { + err = -errno; + pr_warn("failed to iterate BTF objects: %d\n", err); + return err; + } + + fd = bpf_btf_get_fd_by_id(id); + if (fd < 0) { + if (errno == ENOENT) + continue; /* expected race: BTF was unloaded */ + err = -errno; + pr_warn("failed to get BTF object #%d FD: %d\n", id, err); + return err; + } + + len = sizeof(info); + memset(&info, 0, sizeof(info)); + info.name = ptr_to_u64(name); + info.name_len = sizeof(name); + + err = bpf_obj_get_info_by_fd(fd, &info, &len); + if (err) { + err = -errno; + pr_warn("failed to get BTF object #%d info: %d\n", id, err); + goto err_out; + } + + /* ignore non-module BTFs */ + if (!info.kernel_btf || strcmp(name, "vmlinux") == 0) { + close(fd); + continue; + } + + btf = btf_get_from_fd(fd, obj->btf_vmlinux); + err = libbpf_get_error(btf); + if (err) { + pr_warn("failed to load module [%s]'s BTF object #%d: %d\n", + name, id, err); + goto err_out; + } + + err = libbpf_ensure_mem((void **)&obj->btf_modules, &obj->btf_module_cap, + sizeof(*obj->btf_modules), obj->btf_module_cnt + 1); + if (err) + goto err_out; + + mod_btf = &obj->btf_modules[obj->btf_module_cnt++]; + + mod_btf->btf = btf; + mod_btf->id = id; + mod_btf->fd = fd; + mod_btf->name = strdup(name); + if (!mod_btf->name) { + err = -ENOMEM; + goto err_out; + } + continue; + +err_out: + close(fd); + return err; + } + + return 0; +} + +static struct bpf_core_cand_list * +bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id) +{ + struct bpf_core_cand local_cand = {}; + struct bpf_core_cand_list *cands; + const struct btf *main_btf; + const struct btf_type *local_t; + const char *local_name; + size_t local_essent_len; + int err, i; + + local_cand.btf = local_btf; + local_cand.id = local_type_id; + 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); + + cands = calloc(1, sizeof(*cands)); + if (!cands) + return ERR_PTR(-ENOMEM); + + /* Attempt to find target candidates in vmlinux BTF first */ + main_btf = obj->btf_vmlinux_override ?: obj->btf_vmlinux; + err = bpf_core_add_cands(&local_cand, local_essent_len, main_btf, "vmlinux", 1, cands); + if (err) + goto err_out; + + /* if vmlinux BTF has any candidate, don't got for module BTFs */ + if (cands->len) + return cands; + + /* if vmlinux BTF was overridden, don't attempt to load module BTFs */ + if (obj->btf_vmlinux_override) + return cands; + + /* now look through module BTFs, trying to still find candidates */ + err = load_module_btfs(obj); + if (err) + goto err_out; + + for (i = 0; i < obj->btf_module_cnt; i++) { + err = bpf_core_add_cands(&local_cand, local_essent_len, + obj->btf_modules[i].btf, + obj->btf_modules[i].name, + btf__type_cnt(obj->btf_vmlinux), + cands); + if (err) + goto err_out; + } + + return cands; +err_out: + bpf_core_free_cands(cands); + return ERR_PTR(err); +} + +/* 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. + */ +int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id, + const struct btf *targ_btf, __u32 targ_id) +{ + return __bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id, 32); +} + +int bpf_core_types_match(const struct btf *local_btf, __u32 local_id, + const struct btf *targ_btf, __u32 targ_id) +{ + return __bpf_core_types_match(local_btf, local_id, targ_btf, targ_id, false, 32); +} + +static size_t bpf_core_hash_fn(const long key, void *ctx) +{ + return key; +} + +static bool bpf_core_equal_fn(const long k1, const long k2, void *ctx) +{ + return k1 == k2; +} + +static int record_relo_core(struct bpf_program *prog, + const struct bpf_core_relo *core_relo, int insn_idx) +{ + struct reloc_desc *relos, *relo; + + relos = libbpf_reallocarray(prog->reloc_desc, + prog->nr_reloc + 1, sizeof(*relos)); + if (!relos) + return -ENOMEM; + relo = &relos[prog->nr_reloc]; + relo->type = RELO_CORE; + relo->insn_idx = insn_idx; + relo->core_relo = core_relo; + prog->reloc_desc = relos; + prog->nr_reloc++; + return 0; +} + +static const struct bpf_core_relo *find_relo_core(struct bpf_program *prog, int insn_idx) +{ + struct reloc_desc *relo; + int i; + + for (i = 0; i < prog->nr_reloc; i++) { + relo = &prog->reloc_desc[i]; + if (relo->type != RELO_CORE || relo->insn_idx != insn_idx) + continue; + + return relo->core_relo; + } + + return NULL; +} + +static int bpf_core_resolve_relo(struct bpf_program *prog, + const struct bpf_core_relo *relo, + int relo_idx, + const struct btf *local_btf, + struct hashmap *cand_cache, + struct bpf_core_relo_res *targ_res) +{ + struct bpf_core_spec specs_scratch[3] = {}; + struct bpf_core_cand_list *cands = NULL; + const char *prog_name = prog->name; + const struct btf_type *local_type; + const char *local_name; + __u32 local_id = relo->type_id; + int err; + + 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; + + if (relo->kind != BPF_CORE_TYPE_ID_LOCAL && + !hashmap__find(cand_cache, local_id, &cands)) { + cands = bpf_core_find_cands(prog->obj, local_btf, local_id); + if (IS_ERR(cands)) { + pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld\n", + prog_name, relo_idx, local_id, btf_kind_str(local_type), + local_name, PTR_ERR(cands)); + return PTR_ERR(cands); + } + err = hashmap__set(cand_cache, local_id, cands, NULL, NULL); + if (err) { + bpf_core_free_cands(cands); + return err; + } + } + + return bpf_core_calc_relo_insn(prog_name, relo, relo_idx, local_btf, cands, specs_scratch, + targ_res); +} + +static int +bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) +{ + const struct btf_ext_info_sec *sec; + struct bpf_core_relo_res targ_res; + 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 bpf_insn *insn; + const char *sec_name; + int i, err = 0, insn_idx, sec_idx, sec_num; + + if (obj->btf_ext->core_relo_info.len == 0) + return 0; + + if (targ_btf_path) { + obj->btf_vmlinux_override = btf__parse(targ_btf_path, NULL); + err = libbpf_get_error(obj->btf_vmlinux_override); + if (err) { + pr_warn("failed to parse target BTF: %d\n", err); + return err; + } + } + + 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; + sec_num = 0; + for_each_btf_ext_sec(seg, sec) { + sec_idx = seg->sec_idxs[sec_num]; + sec_num++; + + sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off); + if (str_is_empty(sec_name)) { + err = -EINVAL; + goto out; + } + + pr_debug("sec '%s': found %d CO-RE relocations\n", sec_name, sec->num_info); + + for_each_btf_ext_rec(seg, sec, i, rec) { + if (rec->insn_off % BPF_INSN_SZ) + return -EINVAL; + 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->autoload) + continue; + + /* 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; + if (insn_idx >= prog->insns_cnt) + return -EINVAL; + insn = &prog->insns[insn_idx]; + + err = record_relo_core(prog, rec, insn_idx); + if (err) { + pr_warn("prog '%s': relo #%d: failed to record relocation: %d\n", + prog->name, i, err); + goto out; + } + + if (prog->obj->gen_loader) + continue; + + err = bpf_core_resolve_relo(prog, rec, i, obj->btf, cand_cache, &targ_res); + if (err) { + pr_warn("prog '%s': relo #%d: failed to relocate: %d\n", + prog->name, i, err); + goto out; + } + + err = bpf_core_patch_insn(prog->name, insn, insn_idx, rec, i, &targ_res); + if (err) { + pr_warn("prog '%s': relo #%d: failed to patch insn #%u: %d\n", + prog->name, i, insn_idx, err); + goto out; + } + } + } + +out: + /* obj->btf_vmlinux and module BTFs are freed after object load */ + btf__free(obj->btf_vmlinux_override); + obj->btf_vmlinux_override = NULL; + + if (!IS_ERR_OR_NULL(cand_cache)) { + hashmap__for_each_entry(cand_cache, entry, i) { + bpf_core_free_cands(entry->pvalue); + } + hashmap__free(cand_cache); + } + return err; +} + +/* base map load ldimm64 special constant, used also for log fixup logic */ +#define MAP_LDIMM64_POISON_BASE 2001000000 +#define MAP_LDIMM64_POISON_PFX "200100" + +static void poison_map_ldimm64(struct bpf_program *prog, int relo_idx, + int insn_idx, struct bpf_insn *insn, + int map_idx, const struct bpf_map *map) +{ + int i; + + pr_debug("prog '%s': relo #%d: poisoning insn #%d that loads map #%d '%s'\n", + prog->name, relo_idx, insn_idx, map_idx, map->name); + + /* we turn single ldimm64 into two identical invalid calls */ + for (i = 0; i < 2; i++) { + 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 something like: + * invalid func unknown#2001000123 + * where lower 123 is map index into obj->maps[] array + */ + insn->imm = MAP_LDIMM64_POISON_BASE + map_idx; + + insn++; + } +} + +/* 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]; + const struct bpf_map *map; + struct extern_desc *ext; + + switch (relo->type) { + case RELO_LD64: + map = &obj->maps[relo->map_idx]; + if (obj->gen_loader) { + insn[0].src_reg = BPF_PSEUDO_MAP_IDX; + insn[0].imm = relo->map_idx; + } else if (map->autocreate) { + insn[0].src_reg = BPF_PSEUDO_MAP_FD; + insn[0].imm = map->fd; + } else { + poison_map_ldimm64(prog, i, relo->insn_idx, insn, + relo->map_idx, map); + } + break; + case RELO_DATA: + map = &obj->maps[relo->map_idx]; + insn[1].imm = insn[0].imm + relo->sym_off; + if (obj->gen_loader) { + insn[0].src_reg = BPF_PSEUDO_MAP_IDX_VALUE; + insn[0].imm = relo->map_idx; + } else if (map->autocreate) { + insn[0].src_reg = BPF_PSEUDO_MAP_VALUE; + insn[0].imm = map->fd; + } else { + poison_map_ldimm64(prog, i, relo->insn_idx, insn, + relo->map_idx, map); + } + break; + case RELO_EXTERN_VAR: + ext = &obj->externs[relo->sym_off]; + if (ext->type == EXT_KCFG) { + if (obj->gen_loader) { + insn[0].src_reg = BPF_PSEUDO_MAP_IDX_VALUE; + insn[0].imm = obj->kconfig_map_idx; + } else { + 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 && ext->is_set) { /* typed ksyms */ + insn[0].src_reg = BPF_PSEUDO_BTF_ID; + insn[0].imm = ext->ksym.kernel_btf_id; + insn[1].imm = ext->ksym.kernel_btf_obj_fd; + } else { /* typeless ksyms or unresolved typed ksyms */ + insn[0].imm = (__u32)ext->ksym.addr; + insn[1].imm = ext->ksym.addr >> 32; + } + } + break; + case RELO_EXTERN_FUNC: + ext = &obj->externs[relo->sym_off]; + insn[0].src_reg = BPF_PSEUDO_KFUNC_CALL; + if (ext->is_set) { + insn[0].imm = ext->ksym.kernel_btf_id; + insn[0].off = ext->ksym.btf_fd_idx; + } else { /* unresolved weak kfunc */ + insn[0].imm = 0; + insn[0].off = 0; + } + break; + case RELO_SUBPROG_ADDR: + if (insn[0].src_reg != BPF_PSEUDO_FUNC) { + pr_warn("prog '%s': relo #%d: bad insn\n", + prog->name, i); + return -EINVAL; + } + /* handled already */ + break; + case RELO_CALL: + /* handled already */ + break; + case RELO_CORE: + /* will be handled by bpf_program_record_relos() */ + 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; + int i, sec_num, sec_idx, off_adj; + + sec_num = 0; + for_each_btf_ext_sec(ext_info, sec) { + sec_idx = ext_info->sec_idxs[sec_num]; + sec_num++; + if (prog->sec_idx != sec_idx) + 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(obj, 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) +{ + if (!prog->nr_reloc) + return NULL; + return bsearch(&insn_idx, prog->reloc_desc, prog->nr_reloc, + sizeof(*prog->reloc_desc), cmp_relo_by_insn_idx); +} + +static int append_subprog_relos(struct bpf_program *main_prog, struct bpf_program *subprog) +{ + int new_cnt = main_prog->nr_reloc + subprog->nr_reloc; + struct reloc_desc *relos; + int i; + + if (main_prog == subprog) + return 0; + relos = libbpf_reallocarray(main_prog->reloc_desc, new_cnt, sizeof(*relos)); + if (!relos) + return -ENOMEM; + if (subprog->nr_reloc) + memcpy(relos + main_prog->nr_reloc, subprog->reloc_desc, + sizeof(*relos) * subprog->nr_reloc); + + for (i = main_prog->nr_reloc; i < new_cnt; i++) + relos[i].insn_idx += subprog->sub_insn_off; + /* After insn_idx adjustment the 'relos' array is still sorted + * by insn_idx and doesn't break bsearch. + */ + main_prog->reloc_desc = relos; + main_prog->nr_reloc = new_cnt; + return 0; +} + +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) && !insn_is_pseudo_func(insn)) + continue; + + relo = find_prog_insn_relo(prog, insn_idx); + if (relo && relo->type == RELO_EXTERN_FUNC) + /* kfunc relocations will be handled later + * in bpf_object__relocate_data() + */ + continue; + if (relo && relo->type != RELO_CALL && relo->type != RELO_SUBPROG_ADDR) { + 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 + * + * for subprog addr relocation, the relo->sym_off + insn->imm is + * the byte offset in the corresponding section. + */ + if (relo->type == RELO_CALL) + sub_insn_idx = relo->sym_off / BPF_INSN_SZ + insn->imm + 1; + else + sub_insn_idx = (relo->sym_off + insn->imm) / BPF_INSN_SZ; + } else if (insn_is_pseudo_func(insn)) { + /* + * RELO_SUBPROG_ADDR relo is always emitted even if both + * functions are in the same section, so it shouldn't reach here. + */ + pr_warn("prog '%s': missing subprog addr relo for insn #%zu\n", + prog->name, insn_idx); + return -LIBBPF_ERRNO__RELOC; + } 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); + + /* The subprog insns are now appended. Append its relos too. */ + err = append_subprog_relos(main_prog, subprog); + if (err) + return err; + 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; + + 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, 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; + } + + err = bpf_object__reloc_code(obj, prog, prog); + if (err) + return err; + + return 0; +} + +static void +bpf_object__free_relocs(struct bpf_object *obj) +{ + struct bpf_program *prog; + int i; + + /* free up relocation descriptors */ + for (i = 0; i < obj->nr_programs; i++) { + prog = &obj->programs[i]; + zfree(&prog->reloc_desc); + prog->nr_reloc = 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 void bpf_object__sort_relos(struct bpf_object *obj) +{ + int i; + + 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); + } +} + +static int +bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) +{ + struct bpf_program *prog; + size_t i, j; + 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; + } + bpf_object__sort_relos(obj); + } + + /* Before relocating calls pre-process relocations and mark + * few ld_imm64 instructions that points to subprogs. + * Otherwise bpf_object__reloc_code() later would have to consider + * all ld_imm64 insns as relocation candidates. That would + * reduce relocation speed, since amount of find_prog_insn_relo() + * would increase and most of them will fail to find a relo. + */ + for (i = 0; i < obj->nr_programs; i++) { + prog = &obj->programs[i]; + for (j = 0; j < prog->nr_reloc; j++) { + struct reloc_desc *relo = &prog->reloc_desc[j]; + struct bpf_insn *insn = &prog->insns[relo->insn_idx]; + + /* mark the insn, so it's recognized by insn_is_pseudo_func() */ + if (relo->type == RELO_SUBPROG_ADDR) + insn[0].src_reg = BPF_PSEUDO_FUNC; + } + } + + /* 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. + * Append subprog relos to main programs to allow data relos to be + * processed after text is completely relocated. + */ + 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; + if (!prog->autoload) + 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; + } + } + /* Process data relos for main programs */ + for (i = 0; i < obj->nr_programs; i++) { + prog = &obj->programs[i]; + if (prog_is_subprog(obj, prog)) + continue; + if (!prog->autoload) + continue; + 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; + } + } + + return 0; +} + +static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, + Elf64_Shdr *shdr, Elf_Data *data); + +static int bpf_object__collect_map_relos(struct bpf_object *obj, + Elf64_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 = NULL; + struct bpf_program *targ_prog = NULL; + bool is_prog_array, is_map_in_map; + const struct btf_member *member; + const char *name, *mname, *type; + unsigned int moff; + Elf64_Sym *sym; + Elf64_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; + + nrels = shdr->sh_size / shdr->sh_entsize; + for (i = 0; i < nrels; i++) { + rel = elf_rel_by_idx(data, i); + if (!rel) { + pr_warn(".maps relo #%d: failed to get ELF relo\n", i); + return -LIBBPF_ERRNO__FORMAT; + } + + sym = elf_sym_by_idx(obj, ELF64_R_SYM(rel->r_info)); + if (!sym) { + pr_warn(".maps relo #%d: symbol %zx not found\n", + i, (size_t)ELF64_R_SYM(rel->r_info)); + return -LIBBPF_ERRNO__FORMAT; + } + name = elf_sym_str(obj, sym->st_name) ?: "<?>"; + + 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; + } + + is_map_in_map = bpf_map_type__is_map_in_map(map->def.type); + is_prog_array = map->def.type == BPF_MAP_TYPE_PROG_ARRAY; + type = is_map_in_map ? "map" : "prog"; + if (is_map_in_map) { + 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; + } + 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) { + pr_warn(".maps relo #%d: '%s' isn't a valid map reference\n", + i, name); + return -ESRCH; + } + } else if (is_prog_array) { + targ_prog = bpf_object__find_program_by_name(obj, name); + if (!targ_prog) { + pr_warn(".maps relo #%d: '%s' isn't a valid program reference\n", + i, name); + return -ESRCH; + } + if (targ_prog->sec_idx != sym->st_shndx || + targ_prog->sec_insn_off * 8 != sym->st_value || + prog_is_subprog(obj, targ_prog)) { + pr_warn(".maps relo #%d: '%s' isn't an entry-point program\n", + i, name); + return -LIBBPF_ERRNO__RELOC; + } + } else { + return -EINVAL; + } + + 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] = is_map_in_map ? (void *)targ_map : (void *)targ_prog; + + pr_debug(".maps relo #%d: map '%s' slot [%d] points to %s '%s'\n", + i, map->name, moff, type, name); + } + + return 0; +} + +static int bpf_object__collect_relos(struct bpf_object *obj) +{ + int i, err; + + for (i = 0; i < obj->efile.sec_cnt; i++) { + struct elf_sec_desc *sec_desc = &obj->efile.secs[i]; + Elf64_Shdr *shdr; + Elf_Data *data; + int idx; + + if (sec_desc->sec_type != SEC_RELO) + continue; + + shdr = sec_desc->shdr; + data = sec_desc->data; + 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; + } + + bpf_object__sort_relos(obj); + 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; + + if (obj->gen_loader) + return 0; + + 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(obj, 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(obj, FEAT_PROBE_READ_KERN)) + insn->imm = BPF_FUNC_probe_read_str; + break; + default: + break; + } + } + return 0; +} + +static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attach_name, + int *btf_obj_fd, int *btf_type_id); + +/* this is called as prog->sec_def->prog_prepare_load_fn for libbpf-supported sec_defs */ +static int libbpf_prepare_prog_load(struct bpf_program *prog, + struct bpf_prog_load_opts *opts, long cookie) +{ + enum sec_def_flags def = cookie; + + /* old kernels might not support specifying expected_attach_type */ + if ((def & SEC_EXP_ATTACH_OPT) && !kernel_supports(prog->obj, FEAT_EXP_ATTACH_TYPE)) + opts->expected_attach_type = 0; + + if (def & SEC_SLEEPABLE) + opts->prog_flags |= BPF_F_SLEEPABLE; + + if (prog->type == BPF_PROG_TYPE_XDP && (def & SEC_XDP_FRAGS)) + opts->prog_flags |= BPF_F_XDP_HAS_FRAGS; + + if ((def & SEC_ATTACH_BTF) && !prog->attach_btf_id) { + int btf_obj_fd = 0, btf_type_id = 0, err; + const char *attach_name; + + attach_name = strchr(prog->sec_name, '/'); + if (!attach_name) { + /* if BPF program is annotated with just SEC("fentry") + * (or similar) without declaratively specifying + * target, then it is expected that target will be + * specified with bpf_program__set_attach_target() at + * runtime before BPF object load step. If not, then + * there is nothing to load into the kernel as BPF + * verifier won't be able to validate BPF program + * correctness anyways. + */ + pr_warn("prog '%s': no BTF-based attach target is specified, use bpf_program__set_attach_target()\n", + prog->name); + return -EINVAL; + } + attach_name++; /* skip over / */ + + err = libbpf_find_attach_btf_id(prog, attach_name, &btf_obj_fd, &btf_type_id); + if (err) + return err; + + /* cache resolved BTF FD and BTF type ID in the prog */ + prog->attach_btf_obj_fd = btf_obj_fd; + prog->attach_btf_id = btf_type_id; + + /* but by now libbpf common logic is not utilizing + * prog->atach_btf_obj_fd/prog->attach_btf_id anymore because + * this callback is called after opts were populated by + * libbpf, so this callback has to update opts explicitly here + */ + opts->attach_btf_obj_fd = btf_obj_fd; + opts->attach_btf_id = btf_type_id; + } + return 0; +} + +static void fixup_verifier_log(struct bpf_program *prog, char *buf, size_t buf_sz); + +static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog, + struct bpf_insn *insns, int insns_cnt, + const char *license, __u32 kern_version, int *prog_fd) +{ + LIBBPF_OPTS(bpf_prog_load_opts, load_attr); + const char *prog_name = NULL; + char *cp, errmsg[STRERR_BUFSIZE]; + size_t log_buf_size = 0; + char *log_buf = NULL, *tmp; + int btf_fd, ret, err; + bool own_log_buf = true; + __u32 log_level = prog->log_level; + + if (prog->type == BPF_PROG_TYPE_UNSPEC) { + /* + * The program type must be set. Most likely we couldn't find a proper + * section definition at load time, and thus we didn't infer the type. + */ + pr_warn("prog '%s': missing BPF prog type, check ELF section name '%s'\n", + prog->name, prog->sec_name); + return -EINVAL; + } + + if (!insns || !insns_cnt) + return -EINVAL; + + load_attr.expected_attach_type = prog->expected_attach_type; + if (kernel_supports(obj, FEAT_PROG_NAME)) + prog_name = prog->name; + load_attr.attach_prog_fd = prog->attach_prog_fd; + load_attr.attach_btf_obj_fd = prog->attach_btf_obj_fd; + load_attr.attach_btf_id = prog->attach_btf_id; + 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(obj); + if (btf_fd >= 0 && kernel_supports(obj, 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 = log_level; + load_attr.prog_flags = prog->prog_flags; + load_attr.fd_array = obj->fd_array; + + /* adjust load_attr if sec_def provides custom preload callback */ + if (prog->sec_def && prog->sec_def->prog_prepare_load_fn) { + err = prog->sec_def->prog_prepare_load_fn(prog, &load_attr, prog->sec_def->cookie); + if (err < 0) { + pr_warn("prog '%s': failed to prepare load attributes: %d\n", + prog->name, err); + return err; + } + insns = prog->insns; + insns_cnt = prog->insns_cnt; + } + + if (obj->gen_loader) { + bpf_gen__prog_load(obj->gen_loader, prog->type, prog->name, + license, insns, insns_cnt, &load_attr, + prog - obj->programs); + *prog_fd = -1; + return 0; + } + +retry_load: + /* if log_level is zero, we don't request logs initially even if + * custom log_buf is specified; if the program load fails, then we'll + * bump log_level to 1 and use either custom log_buf or we'll allocate + * our own and retry the load to get details on what failed + */ + if (log_level) { + if (prog->log_buf) { + log_buf = prog->log_buf; + log_buf_size = prog->log_size; + own_log_buf = false; + } else if (obj->log_buf) { + log_buf = obj->log_buf; + log_buf_size = obj->log_size; + own_log_buf = false; + } else { + log_buf_size = max((size_t)BPF_LOG_BUF_SIZE, log_buf_size * 2); + tmp = realloc(log_buf, log_buf_size); + if (!tmp) { + ret = -ENOMEM; + goto out; + } + log_buf = tmp; + log_buf[0] = '\0'; + own_log_buf = true; + } + } + + load_attr.log_buf = log_buf; + load_attr.log_size = log_buf_size; + load_attr.log_level = log_level; + + ret = bpf_prog_load(prog->type, prog_name, license, insns, insns_cnt, &load_attr); + if (ret >= 0) { + if (log_level && own_log_buf) { + pr_debug("prog '%s': -- BEGIN PROG LOAD LOG --\n%s-- END PROG LOAD LOG --\n", + prog->name, log_buf); + } + + if (obj->has_rodata && kernel_supports(obj, FEAT_PROG_BIND_MAP)) { + struct bpf_map *map; + int i; + + for (i = 0; i < obj->nr_maps; i++) { + map = &prog->obj->maps[i]; + if (map->libbpf_type != LIBBPF_MAP_RODATA) + continue; + + if (bpf_prog_bind_map(ret, bpf_map__fd(map), NULL)) { + cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warn("prog '%s': failed to bind map '%s': %s\n", + prog->name, map->real_name, cp); + /* Don't fail hard if can't bind rodata. */ + } + } + } + + *prog_fd = ret; + ret = 0; + goto out; + } + + if (log_level == 0) { + log_level = 1; + goto retry_load; + } + /* On ENOSPC, increase log buffer size and retry, unless custom + * log_buf is specified. + * Be careful to not overflow u32, though. Kernel's log buf size limit + * isn't part of UAPI so it can always be bumped to full 4GB. So don't + * multiply by 2 unless we are sure we'll fit within 32 bits. + * Currently, we'll get -EINVAL when we reach (UINT_MAX >> 2). + */ + if (own_log_buf && errno == ENOSPC && log_buf_size <= UINT_MAX / 2) + goto retry_load; + + ret = -errno; + + /* post-process verifier log to improve error descriptions */ + fixup_verifier_log(prog, log_buf, log_buf_size); + + cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warn("prog '%s': BPF program load failed: %s\n", prog->name, cp); + pr_perm_msg(ret); + + if (own_log_buf && log_buf && log_buf[0] != '\0') { + pr_warn("prog '%s': -- BEGIN PROG LOAD LOG --\n%s-- END PROG LOAD LOG --\n", + prog->name, log_buf); + } + +out: + if (own_log_buf) + free(log_buf); + return ret; +} + +static char *find_prev_line(char *buf, char *cur) +{ + char *p; + + if (cur == buf) /* end of a log buf */ + return NULL; + + p = cur - 1; + while (p - 1 >= buf && *(p - 1) != '\n') + p--; + + return p; +} + +static void patch_log(char *buf, size_t buf_sz, size_t log_sz, + char *orig, size_t orig_sz, const char *patch) +{ + /* size of the remaining log content to the right from the to-be-replaced part */ + size_t rem_sz = (buf + log_sz) - (orig + orig_sz); + size_t patch_sz = strlen(patch); + + if (patch_sz != orig_sz) { + /* If patch line(s) are longer than original piece of verifier log, + * shift log contents by (patch_sz - orig_sz) bytes to the right + * starting from after to-be-replaced part of the log. + * + * If patch line(s) are shorter than original piece of verifier log, + * shift log contents by (orig_sz - patch_sz) bytes to the left + * starting from after to-be-replaced part of the log + * + * We need to be careful about not overflowing available + * buf_sz capacity. If that's the case, we'll truncate the end + * of the original log, as necessary. + */ + if (patch_sz > orig_sz) { + if (orig + patch_sz >= buf + buf_sz) { + /* patch is big enough to cover remaining space completely */ + patch_sz -= (orig + patch_sz) - (buf + buf_sz) + 1; + rem_sz = 0; + } else if (patch_sz - orig_sz > buf_sz - log_sz) { + /* patch causes part of remaining log to be truncated */ + rem_sz -= (patch_sz - orig_sz) - (buf_sz - log_sz); + } + } + /* shift remaining log to the right by calculated amount */ + memmove(orig + patch_sz, orig + orig_sz, rem_sz); + } + + memcpy(orig, patch, patch_sz); +} + +static void fixup_log_failed_core_relo(struct bpf_program *prog, + char *buf, size_t buf_sz, size_t log_sz, + char *line1, char *line2, char *line3) +{ + /* Expected log for failed and not properly guarded CO-RE relocation: + * line1 -> 123: (85) call unknown#195896080 + * line2 -> invalid func unknown#195896080 + * line3 -> <anything else or end of buffer> + * + * "123" is the index of the instruction that was poisoned. We extract + * instruction index to find corresponding CO-RE relocation and + * replace this part of the log with more relevant information about + * failed CO-RE relocation. + */ + const struct bpf_core_relo *relo; + struct bpf_core_spec spec; + char patch[512], spec_buf[256]; + int insn_idx, err, spec_len; + + if (sscanf(line1, "%d: (%*d) call unknown#195896080\n", &insn_idx) != 1) + return; + + relo = find_relo_core(prog, insn_idx); + if (!relo) + return; + + err = bpf_core_parse_spec(prog->name, prog->obj->btf, relo, &spec); + if (err) + return; + + spec_len = bpf_core_format_spec(spec_buf, sizeof(spec_buf), &spec); + snprintf(patch, sizeof(patch), + "%d: <invalid CO-RE relocation>\n" + "failed to resolve CO-RE relocation %s%s\n", + insn_idx, spec_buf, spec_len >= sizeof(spec_buf) ? "..." : ""); + + patch_log(buf, buf_sz, log_sz, line1, line3 - line1, patch); +} + +static void fixup_log_missing_map_load(struct bpf_program *prog, + char *buf, size_t buf_sz, size_t log_sz, + char *line1, char *line2, char *line3) +{ + /* Expected log for failed and not properly guarded CO-RE relocation: + * line1 -> 123: (85) call unknown#2001000345 + * line2 -> invalid func unknown#2001000345 + * line3 -> <anything else or end of buffer> + * + * "123" is the index of the instruction that was poisoned. + * "345" in "2001000345" are map index in obj->maps to fetch map name. + */ + struct bpf_object *obj = prog->obj; + const struct bpf_map *map; + int insn_idx, map_idx; + char patch[128]; + + if (sscanf(line1, "%d: (%*d) call unknown#%d\n", &insn_idx, &map_idx) != 2) + return; + + map_idx -= MAP_LDIMM64_POISON_BASE; + if (map_idx < 0 || map_idx >= obj->nr_maps) + return; + map = &obj->maps[map_idx]; + + snprintf(patch, sizeof(patch), + "%d: <invalid BPF map reference>\n" + "BPF map '%s' is referenced but wasn't created\n", + insn_idx, map->name); + + patch_log(buf, buf_sz, log_sz, line1, line3 - line1, patch); +} + +static void fixup_verifier_log(struct bpf_program *prog, char *buf, size_t buf_sz) +{ + /* look for familiar error patterns in last N lines of the log */ + const size_t max_last_line_cnt = 10; + char *prev_line, *cur_line, *next_line; + size_t log_sz; + int i; + + if (!buf) + return; + + log_sz = strlen(buf) + 1; + next_line = buf + log_sz - 1; + + for (i = 0; i < max_last_line_cnt; i++, next_line = cur_line) { + cur_line = find_prev_line(buf, next_line); + if (!cur_line) + return; + + /* failed CO-RE relocation case */ + if (str_has_pfx(cur_line, "invalid func unknown#195896080\n")) { + prev_line = find_prev_line(buf, cur_line); + if (!prev_line) + continue; + + fixup_log_failed_core_relo(prog, buf, buf_sz, log_sz, + prev_line, cur_line, next_line); + return; + } else if (str_has_pfx(cur_line, "invalid func unknown#"MAP_LDIMM64_POISON_PFX)) { + prev_line = find_prev_line(buf, cur_line); + if (!prev_line) + continue; + + fixup_log_missing_map_load(prog, buf, buf_sz, log_sz, + prev_line, cur_line, next_line); + return; + } + } +} + +static int bpf_program_record_relos(struct bpf_program *prog) +{ + struct bpf_object *obj = prog->obj; + int i; + + for (i = 0; i < prog->nr_reloc; i++) { + struct reloc_desc *relo = &prog->reloc_desc[i]; + struct extern_desc *ext = &obj->externs[relo->sym_off]; + + switch (relo->type) { + case RELO_EXTERN_VAR: + if (ext->type != EXT_KSYM) + continue; + bpf_gen__record_extern(obj->gen_loader, ext->name, + ext->is_weak, !ext->ksym.type_id, + BTF_KIND_VAR, relo->insn_idx); + break; + case RELO_EXTERN_FUNC: + bpf_gen__record_extern(obj->gen_loader, ext->name, + ext->is_weak, false, BTF_KIND_FUNC, + relo->insn_idx); + break; + case RELO_CORE: { + struct bpf_core_relo cr = { + .insn_off = relo->insn_idx * 8, + .type_id = relo->core_relo->type_id, + .access_str_off = relo->core_relo->access_str_off, + .kind = relo->core_relo->kind, + }; + + bpf_gen__record_relo_core(obj->gen_loader, &cr); + break; + } + default: + continue; + } + } + return 0; +} + +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->autoload) { + pr_debug("prog '%s': skipped loading\n", prog->name); + continue; + } + prog->log_level |= log_level; + + if (obj->gen_loader) + bpf_program_record_relos(prog); + + err = bpf_object_load_prog(obj, prog, prog->insns, prog->insns_cnt, + obj->license, obj->kern_version, &prog->fd); + if (err) { + pr_warn("prog '%s': failed to load: %d\n", prog->name, err); + return err; + } + } + + bpf_object__free_relocs(obj); + return 0; +} + +static const struct bpf_sec_def *find_sec_def(const char *sec_name); + +static int bpf_object_init_progs(struct bpf_object *obj, const struct bpf_object_open_opts *opts) +{ + struct bpf_program *prog; + int err; + + 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 */ + pr_debug("prog '%s': unrecognized ELF section name '%s'\n", + prog->name, prog->sec_name); + continue; + } + + prog->type = prog->sec_def->prog_type; + prog->expected_attach_type = prog->sec_def->expected_attach_type; + + /* sec_def can have custom callback which should be called + * after bpf_program is initialized to adjust its properties + */ + if (prog->sec_def->prog_setup_fn) { + err = prog->sec_def->prog_setup_fn(prog, prog->sec_def->cookie); + if (err < 0) { + pr_warn("prog '%s': failed to initialize: %d\n", + prog->name, err); + return err; + } + } + } + + return 0; +} + +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, *btf_tmp_path; + struct bpf_object *obj; + char tmp_name[64]; + int err; + char *log_buf; + size_t log_size; + __u32 log_level; + + 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); + } + + log_buf = OPTS_GET(opts, kernel_log_buf, NULL); + log_size = OPTS_GET(opts, kernel_log_size, 0); + log_level = OPTS_GET(opts, kernel_log_level, 0); + if (log_size > UINT_MAX) + return ERR_PTR(-EINVAL); + if (log_size && !log_buf) + return ERR_PTR(-EINVAL); + + obj = bpf_object__new(path, obj_buf, obj_buf_sz, obj_name); + if (IS_ERR(obj)) + return obj; + + obj->log_buf = log_buf; + obj->log_size = log_size; + obj->log_level = log_level; + + btf_tmp_path = OPTS_GET(opts, btf_custom_path, NULL); + if (btf_tmp_path) { + if (strlen(btf_tmp_path) >= PATH_MAX) { + err = -ENAMETOOLONG; + goto out; + } + obj->btf_custom_path = strdup(btf_tmp_path); + if (!obj->btf_custom_path) { + err = -ENOMEM; + goto out; + } + } + + 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_fixup_btf(obj); + err = err ? : bpf_object__init_maps(obj, opts); + err = err ? : bpf_object_init_progs(obj, opts); + err = err ? : bpf_object__collect_relos(obj); + if (err) + goto out; + + bpf_object__elf_finish(obj); + + return obj; +out: + bpf_object__close(obj); + return ERR_PTR(err); +} + +struct bpf_object * +bpf_object__open_file(const char *path, const struct bpf_object_open_opts *opts) +{ + if (!path) + return libbpf_err_ptr(-EINVAL); + + pr_debug("loading %s\n", path); + + return libbpf_ptr(bpf_object_open(path, NULL, 0, opts)); +} + +struct bpf_object *bpf_object__open(const char *path) +{ + return bpf_object__open_file(path, NULL); +} + +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 libbpf_err_ptr(-EINVAL); + + return libbpf_ptr(bpf_object_open(NULL, obj_buf, obj_buf_sz, opts)); +} + +static int bpf_object_unload(struct bpf_object *obj) +{ + size_t i; + + if (!obj) + return libbpf_err(-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(obj, FEAT_ARRAY_MMAP)) + m->def.map_flags ^= BPF_F_MMAPABLE; + } + + return 0; +} + +int libbpf_kallsyms_parse(kallsyms_cb_t cb, void *ctx) +{ + char sym_type, sym_name[500]; + unsigned long long sym_addr; + 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; + break; + } + + err = cb(sym_addr, sym_type, sym_name, ctx); + if (err) + break; + } + + fclose(f); + return err; +} + +static int kallsyms_cb(unsigned long long sym_addr, char sym_type, + const char *sym_name, void *ctx) +{ + struct bpf_object *obj = ctx; + const struct btf_type *t; + struct extern_desc *ext; + + ext = find_extern_by_name(obj, sym_name); + if (!ext || ext->type != EXT_KSYM) + return 0; + + t = btf__type_by_id(obj->btf, ext->btf_id); + if (!btf_is_var(t)) + return 0; + + 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); + return -EINVAL; + } + if (!ext->is_set) { + ext->is_set = true; + ext->ksym.addr = sym_addr; + pr_debug("extern (ksym) '%s': set to 0x%llx\n", sym_name, sym_addr); + } + return 0; +} + +static int bpf_object__read_kallsyms_file(struct bpf_object *obj) +{ + return libbpf_kallsyms_parse(kallsyms_cb, obj); +} + +static int find_ksym_btf_id(struct bpf_object *obj, const char *ksym_name, + __u16 kind, struct btf **res_btf, + struct module_btf **res_mod_btf) +{ + struct module_btf *mod_btf; + struct btf *btf; + int i, id, err; + + btf = obj->btf_vmlinux; + mod_btf = NULL; + id = btf__find_by_name_kind(btf, ksym_name, kind); + + if (id == -ENOENT) { + err = load_module_btfs(obj); + if (err) + return err; + + for (i = 0; i < obj->btf_module_cnt; i++) { + /* we assume module_btf's BTF FD is always >0 */ + mod_btf = &obj->btf_modules[i]; + btf = mod_btf->btf; + id = btf__find_by_name_kind_own(btf, ksym_name, kind); + if (id != -ENOENT) + break; + } + } + if (id <= 0) + return -ESRCH; + + *res_btf = btf; + *res_mod_btf = mod_btf; + return id; +} + +static int bpf_object__resolve_ksym_var_btf_id(struct bpf_object *obj, + struct extern_desc *ext) +{ + const struct btf_type *targ_var, *targ_type; + __u32 targ_type_id, local_type_id; + struct module_btf *mod_btf = NULL; + const char *targ_var_name; + struct btf *btf = NULL; + int id, err; + + id = find_ksym_btf_id(obj, ext->name, BTF_KIND_VAR, &btf, &mod_btf); + if (id < 0) { + if (id == -ESRCH && ext->is_weak) + return 0; + pr_warn("extern (var ksym) '%s': not found in kernel BTF\n", + ext->name); + return id; + } + + /* find local type_id */ + local_type_id = ext->ksym.type_id; + + /* find target type_id */ + targ_var = btf__type_by_id(btf, id); + targ_var_name = btf__name_by_offset(btf, targ_var->name_off); + targ_type = skip_mods_and_typedefs(btf, targ_var->type, &targ_type_id); + + err = bpf_core_types_are_compat(obj->btf, local_type_id, + btf, targ_type_id); + if (err <= 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(btf, targ_type->name_off); + + pr_warn("extern (var 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.kernel_btf_obj_fd = mod_btf ? mod_btf->fd : 0; + ext->ksym.kernel_btf_id = id; + pr_debug("extern (var 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_ksym_func_btf_id(struct bpf_object *obj, + struct extern_desc *ext) +{ + int local_func_proto_id, kfunc_proto_id, kfunc_id; + struct module_btf *mod_btf = NULL; + const struct btf_type *kern_func; + struct btf *kern_btf = NULL; + int ret; + + local_func_proto_id = ext->ksym.type_id; + + kfunc_id = find_ksym_btf_id(obj, ext->name, BTF_KIND_FUNC, &kern_btf, &mod_btf); + if (kfunc_id < 0) { + if (kfunc_id == -ESRCH && ext->is_weak) + return 0; + pr_warn("extern (func ksym) '%s': not found in kernel or module BTFs\n", + ext->name); + return kfunc_id; + } + + kern_func = btf__type_by_id(kern_btf, kfunc_id); + kfunc_proto_id = kern_func->type; + + ret = bpf_core_types_are_compat(obj->btf, local_func_proto_id, + kern_btf, kfunc_proto_id); + if (ret <= 0) { + pr_warn("extern (func ksym) '%s': func_proto [%d] incompatible with kernel [%d]\n", + ext->name, local_func_proto_id, kfunc_proto_id); + return -EINVAL; + } + + /* set index for module BTF fd in fd_array, if unset */ + if (mod_btf && !mod_btf->fd_array_idx) { + /* insn->off is s16 */ + if (obj->fd_array_cnt == INT16_MAX) { + pr_warn("extern (func ksym) '%s': module BTF fd index %d too big to fit in bpf_insn offset\n", + ext->name, mod_btf->fd_array_idx); + return -E2BIG; + } + /* Cannot use index 0 for module BTF fd */ + if (!obj->fd_array_cnt) + obj->fd_array_cnt = 1; + + ret = libbpf_ensure_mem((void **)&obj->fd_array, &obj->fd_array_cap, sizeof(int), + obj->fd_array_cnt + 1); + if (ret) + return ret; + mod_btf->fd_array_idx = obj->fd_array_cnt; + /* we assume module BTF FD is always >0 */ + obj->fd_array[obj->fd_array_cnt++] = mod_btf->fd; + } + + ext->is_set = true; + ext->ksym.kernel_btf_id = kfunc_id; + ext->ksym.btf_fd_idx = mod_btf ? mod_btf->fd_array_idx : 0; + pr_debug("extern (func ksym) '%s': resolved to kernel [%d]\n", + ext->name, kfunc_id); + + return 0; +} + +static int bpf_object__resolve_ksyms_btf_id(struct bpf_object *obj) +{ + const struct btf_type *t; + struct extern_desc *ext; + int i, err; + + for (i = 0; i < obj->nr_extern; i++) { + ext = &obj->externs[i]; + if (ext->type != EXT_KSYM || !ext->ksym.type_id) + continue; + + if (obj->gen_loader) { + ext->is_set = true; + ext->ksym.kernel_btf_obj_fd = 0; + ext->ksym.kernel_btf_id = 0; + continue; + } + t = btf__type_by_id(obj->btf, ext->btf_id); + if (btf_is_var(t)) + err = bpf_object__resolve_ksym_var_btf_id(obj, ext); + else + err = bpf_object__resolve_ksym_func_btf_id(obj, ext); + if (err) + return err; + } + 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_KSYM) { + if (ext->ksym.type_id) + need_vmlinux_btf = true; + else + need_kallsyms = true; + continue; + } else if (ext->type == EXT_KCFG) { + void *ext_ptr = kcfg_data + ext->kcfg.data_off; + __u64 value = 0; + + /* Kconfig externs need actual /proc/config.gz */ + if (str_has_pfx(ext->name, "CONFIG_")) { + need_config = true; + continue; + } + + /* Virtual kcfg externs are customly handled by libbpf */ + if (strcmp(ext->name, "LINUX_KERNEL_VERSION") == 0) { + value = get_kernel_version(); + if (!value) { + pr_warn("extern (kcfg) '%s': failed to get kernel version\n", ext->name); + return -EINVAL; + } + } else if (strcmp(ext->name, "LINUX_HAS_BPF_COOKIE") == 0) { + value = kernel_supports(obj, FEAT_BPF_COOKIE); + } else if (strcmp(ext->name, "LINUX_HAS_SYSCALL_WRAPPER") == 0) { + value = kernel_supports(obj, FEAT_SYSCALL_WRAPPER); + } else if (!str_has_pfx(ext->name, "LINUX_") || !ext->is_weak) { + /* Currently libbpf supports only CONFIG_ and LINUX_ prefixed + * __kconfig externs, where LINUX_ ones are virtual and filled out + * customly by libbpf (their values don't come from Kconfig). + * If LINUX_xxx variable is not recognized by libbpf, but is marked + * __weak, it defaults to zero value, just like for CONFIG_xxx + * externs. + */ + pr_warn("extern (kcfg) '%s': unrecognized virtual extern\n", ext->name); + return -EINVAL; + } + + err = set_kcfg_value_num(ext, ext_ptr, value); + if (err) + return err; + pr_debug("extern (kcfg) '%s': set to 0x%llx\n", + ext->name, (long long)value); + } else { + pr_warn("extern '%s': unrecognized extern kind\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; +} + +static int bpf_object_load(struct bpf_object *obj, int extra_log_level, const char *target_btf_path) +{ + int err, i; + + if (!obj) + return libbpf_err(-EINVAL); + + if (obj->loaded) { + pr_warn("object '%s': load can't be attempted twice\n", obj->name); + return libbpf_err(-EINVAL); + } + + if (obj->gen_loader) + bpf_gen__init(obj->gen_loader, extra_log_level, obj->nr_programs, obj->nr_maps); + + err = bpf_object__probe_loading(obj); + err = err ? : bpf_object__load_vmlinux_btf(obj, false); + 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, obj->btf_custom_path ? : target_btf_path); + err = err ? : bpf_object__load_progs(obj, extra_log_level); + err = err ? : bpf_object_init_prog_arrays(obj); + + if (obj->gen_loader) { + /* reset FDs */ + if (obj->btf) + btf__set_fd(obj->btf, -1); + for (i = 0; i < obj->nr_maps; i++) + obj->maps[i].fd = -1; + if (!err) + err = bpf_gen__finish(obj->gen_loader, obj->nr_programs, obj->nr_maps); + } + + /* clean up fd_array */ + zfree(&obj->fd_array); + + /* clean up module BTFs */ + for (i = 0; i < obj->btf_module_cnt; i++) { + close(obj->btf_modules[i].fd); + btf__free(obj->btf_modules[i].btf); + free(obj->btf_modules[i].name); + } + free(obj->btf_modules); + + /* clean up vmlinux BTF */ + 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 libbpf_err(err); +} + +int bpf_object__load(struct bpf_object *obj) +{ + return bpf_object_load(obj, 0, NULL); +} + +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(struct bpf_program *prog, const char *path) +{ + char *cp, errmsg[STRERR_BUFSIZE]; + int err; + + if (prog->fd < 0) { + pr_warn("prog '%s': can't pin program that wasn't loaded\n", prog->name); + return libbpf_err(-EINVAL); + } + + err = make_parent_dir(path); + if (err) + return libbpf_err(err); + + err = check_path(path); + if (err) + return libbpf_err(err); + + if (bpf_obj_pin(prog->fd, path)) { + err = -errno; + cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); + pr_warn("prog '%s': failed to pin at '%s': %s\n", prog->name, path, cp); + return libbpf_err(err); + } + + pr_debug("prog '%s': pinned at '%s'\n", prog->name, path); + return 0; +} + +int bpf_program__unpin(struct bpf_program *prog, const char *path) +{ + int err; + + if (prog->fd < 0) { + pr_warn("prog '%s': can't unpin program that wasn't loaded\n", prog->name); + return libbpf_err(-EINVAL); + } + + err = check_path(path); + if (err) + return libbpf_err(err); + + err = unlink(path); + if (err) + return libbpf_err(-errno); + + pr_debug("prog '%s': unpinned from '%s'\n", prog->name, path); + 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 libbpf_err(-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 libbpf_err(-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 libbpf_err(-EINVAL); + } else if (map->pinned) { + pr_warn("map '%s' already pinned\n", bpf_map__name(map)); + return libbpf_err(-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 libbpf_err(err); + + err = check_path(map->pin_path); + if (err) + return libbpf_err(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 libbpf_err(err); +} + +int bpf_map__unpin(struct bpf_map *map, const char *path) +{ + int err; + + if (map == NULL) { + pr_warn("invalid map pointer\n"); + return libbpf_err(-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 libbpf_err(-EINVAL); + } + path = map->pin_path; + } else if (!path) { + pr_warn("no path to unpin map '%s' from\n", + bpf_map__name(map)); + return libbpf_err(-EINVAL); + } + + err = check_path(path); + if (err) + return libbpf_err(err); + + err = unlink(path); + if (err != 0) + return libbpf_err(-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 libbpf_err(-errno); + } + + free(map->pin_path); + map->pin_path = new; + return 0; +} + +__alias(bpf_map__pin_path) +const char *bpf_map__get_pin_path(const struct bpf_map *map); + +const char *bpf_map__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 libbpf_err(-ENOENT); + + if (!obj->loaded) { + pr_warn("object not yet loaded; load it first\n"); + return libbpf_err(-ENOENT); + } + + bpf_object__for_each_map(map, obj) { + char *pin_path = NULL; + char buf[PATH_MAX]; + + if (!map->autocreate) + continue; + + if (path) { + err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map)); + if (err) + 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_object__prev_map(obj, map))) { + if (!map->pin_path) + continue; + + bpf_map__unpin(map, NULL); + } + + return libbpf_err(err); +} + +int bpf_object__unpin_maps(struct bpf_object *obj, const char *path) +{ + struct bpf_map *map; + int err; + + if (!obj) + return libbpf_err(-ENOENT); + + bpf_object__for_each_map(map, obj) { + char *pin_path = NULL; + char buf[PATH_MAX]; + + if (path) { + err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map)); + if (err) + return libbpf_err(err); + sanitize_pin_path(buf); + pin_path = buf; + } else if (!map->pin_path) { + continue; + } + + err = bpf_map__unpin(map, pin_path); + if (err) + return libbpf_err(err); + } + + return 0; +} + +int bpf_object__pin_programs(struct bpf_object *obj, const char *path) +{ + struct bpf_program *prog; + char buf[PATH_MAX]; + int err; + + if (!obj) + return libbpf_err(-ENOENT); + + if (!obj->loaded) { + pr_warn("object not yet loaded; load it first\n"); + return libbpf_err(-ENOENT); + } + + bpf_object__for_each_program(prog, obj) { + err = pathname_concat(buf, sizeof(buf), path, prog->name); + if (err) + goto err_unpin_programs; + + err = bpf_program__pin(prog, buf); + if (err) + goto err_unpin_programs; + } + + return 0; + +err_unpin_programs: + while ((prog = bpf_object__prev_program(obj, prog))) { + if (pathname_concat(buf, sizeof(buf), path, prog->name)) + continue; + + bpf_program__unpin(prog, buf); + } + + return libbpf_err(err); +} + +int bpf_object__unpin_programs(struct bpf_object *obj, const char *path) +{ + struct bpf_program *prog; + int err; + + if (!obj) + return libbpf_err(-ENOENT); + + bpf_object__for_each_program(prog, obj) { + char buf[PATH_MAX]; + + err = pathname_concat(buf, sizeof(buf), path, prog->name); + if (err) + return libbpf_err(err); + + err = bpf_program__unpin(prog, buf); + if (err) + return libbpf_err(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 libbpf_err(err); + + err = bpf_object__pin_programs(obj, path); + if (err) { + bpf_object__unpin_maps(obj, path); + return libbpf_err(err); + } + + return 0; +} + +static void bpf_map__destroy(struct bpf_map *map) +{ + 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->real_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; + + usdt_manager_free(obj->usdt_man); + obj->usdt_man = NULL; + + bpf_gen__free(obj->gen_loader); + 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->btf_custom_path); + 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); + + free(obj); +} + +const char *bpf_object__name(const struct bpf_object *obj) +{ + return obj ? obj->name : libbpf_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_kversion(struct bpf_object *obj, __u32 kern_version) +{ + if (obj->loaded) + return libbpf_err(-EINVAL); + + obj->kern_version = kern_version; + + return 0; +} + +int bpf_object__gen_loader(struct bpf_object *obj, struct gen_loader_opts *opts) +{ + struct bpf_gen *gen; + + if (!opts) + return -EFAULT; + if (!OPTS_VALID(opts, gen_loader_opts)) + return -EINVAL; + gen = calloc(sizeof(*gen), 1); + if (!gen) + return -ENOMEM; + gen->opts = opts; + obj->gen_loader = gen; + return 0; +} + +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 errno = EINVAL, 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_object__next_program(const struct bpf_object *obj, struct bpf_program *prev) +{ + 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_object__prev_program(const struct bpf_object *obj, struct bpf_program *next) +{ + struct bpf_program *prog = next; + + do { + prog = __bpf_program__iter(prog, obj, false); + } while (prog && prog_is_subprog(obj, prog)); + + return prog; +} + +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; +} + +bool bpf_program__autoload(const struct bpf_program *prog) +{ + return prog->autoload; +} + +int bpf_program__set_autoload(struct bpf_program *prog, bool autoload) +{ + if (prog->obj->loaded) + return libbpf_err(-EINVAL); + + prog->autoload = autoload; + return 0; +} + +bool bpf_program__autoattach(const struct bpf_program *prog) +{ + return prog->autoattach; +} + +void bpf_program__set_autoattach(struct bpf_program *prog, bool autoattach) +{ + prog->autoattach = autoattach; +} + +const struct bpf_insn *bpf_program__insns(const struct bpf_program *prog) +{ + return prog->insns; +} + +size_t bpf_program__insn_cnt(const struct bpf_program *prog) +{ + return prog->insns_cnt; +} + +int bpf_program__set_insns(struct bpf_program *prog, + struct bpf_insn *new_insns, size_t new_insn_cnt) +{ + struct bpf_insn *insns; + + if (prog->obj->loaded) + return -EBUSY; + + insns = libbpf_reallocarray(prog->insns, new_insn_cnt, sizeof(*insns)); + if (!insns) { + pr_warn("prog '%s': failed to realloc prog code\n", prog->name); + return -ENOMEM; + } + memcpy(insns, new_insns, new_insn_cnt * sizeof(*insns)); + + prog->insns = insns; + prog->insns_cnt = new_insn_cnt; + return 0; +} + +int bpf_program__fd(const struct bpf_program *prog) +{ + if (!prog) + return libbpf_err(-EINVAL); + + if (prog->fd < 0) + return libbpf_err(-ENOENT); + + return prog->fd; +} + +__alias(bpf_program__type) +enum bpf_prog_type bpf_program__get_type(const struct bpf_program *prog); + +enum bpf_prog_type bpf_program__type(const struct bpf_program *prog) +{ + return prog->type; +} + +int bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type) +{ + if (prog->obj->loaded) + return libbpf_err(-EBUSY); + + prog->type = type; + return 0; +} + +__alias(bpf_program__expected_attach_type) +enum bpf_attach_type bpf_program__get_expected_attach_type(const struct bpf_program *prog); + +enum bpf_attach_type bpf_program__expected_attach_type(const struct bpf_program *prog) +{ + return prog->expected_attach_type; +} + +int bpf_program__set_expected_attach_type(struct bpf_program *prog, + enum bpf_attach_type type) +{ + if (prog->obj->loaded) + return libbpf_err(-EBUSY); + + prog->expected_attach_type = type; + return 0; +} + +__u32 bpf_program__flags(const struct bpf_program *prog) +{ + return prog->prog_flags; +} + +int bpf_program__set_flags(struct bpf_program *prog, __u32 flags) +{ + if (prog->obj->loaded) + return libbpf_err(-EBUSY); + + prog->prog_flags = flags; + return 0; +} + +__u32 bpf_program__log_level(const struct bpf_program *prog) +{ + return prog->log_level; +} + +int bpf_program__set_log_level(struct bpf_program *prog, __u32 log_level) +{ + if (prog->obj->loaded) + return libbpf_err(-EBUSY); + + prog->log_level = log_level; + return 0; +} + +const char *bpf_program__log_buf(const struct bpf_program *prog, size_t *log_size) +{ + *log_size = prog->log_size; + return prog->log_buf; +} + +int bpf_program__set_log_buf(struct bpf_program *prog, char *log_buf, size_t log_size) +{ + if (log_size && !log_buf) + return -EINVAL; + if (prog->log_size > UINT_MAX) + return -EINVAL; + if (prog->obj->loaded) + return -EBUSY; + + prog->log_buf = log_buf; + prog->log_size = log_size; + return 0; +} + +#define SEC_DEF(sec_pfx, ptype, atype, flags, ...) { \ + .sec = (char *)sec_pfx, \ + .prog_type = BPF_PROG_TYPE_##ptype, \ + .expected_attach_type = atype, \ + .cookie = (long)(flags), \ + .prog_prepare_load_fn = libbpf_prepare_prog_load, \ + __VA_ARGS__ \ +} + +static int attach_kprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_uprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_ksyscall(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_usdt(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_raw_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_trace(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_link **link); + +static const struct bpf_sec_def section_defs[] = { + SEC_DEF("socket", SOCKET_FILTER, 0, SEC_NONE), + SEC_DEF("sk_reuseport/migrate", SK_REUSEPORT, BPF_SK_REUSEPORT_SELECT_OR_MIGRATE, SEC_ATTACHABLE), + SEC_DEF("sk_reuseport", SK_REUSEPORT, BPF_SK_REUSEPORT_SELECT, SEC_ATTACHABLE), + SEC_DEF("kprobe+", KPROBE, 0, SEC_NONE, attach_kprobe), + SEC_DEF("uprobe+", KPROBE, 0, SEC_NONE, attach_uprobe), + SEC_DEF("uprobe.s+", KPROBE, 0, SEC_SLEEPABLE, attach_uprobe), + SEC_DEF("kretprobe+", KPROBE, 0, SEC_NONE, attach_kprobe), + SEC_DEF("uretprobe+", KPROBE, 0, SEC_NONE, attach_uprobe), + SEC_DEF("uretprobe.s+", KPROBE, 0, SEC_SLEEPABLE, attach_uprobe), + SEC_DEF("kprobe.multi+", KPROBE, BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi), + SEC_DEF("kretprobe.multi+", KPROBE, BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi), + SEC_DEF("ksyscall+", KPROBE, 0, SEC_NONE, attach_ksyscall), + SEC_DEF("kretsyscall+", KPROBE, 0, SEC_NONE, attach_ksyscall), + SEC_DEF("usdt+", KPROBE, 0, SEC_NONE, attach_usdt), + SEC_DEF("tc", SCHED_CLS, 0, SEC_NONE), + SEC_DEF("classifier", SCHED_CLS, 0, SEC_NONE), + SEC_DEF("action", SCHED_ACT, 0, SEC_NONE), + SEC_DEF("tracepoint+", TRACEPOINT, 0, SEC_NONE, attach_tp), + SEC_DEF("tp+", TRACEPOINT, 0, SEC_NONE, attach_tp), + SEC_DEF("raw_tracepoint+", RAW_TRACEPOINT, 0, SEC_NONE, attach_raw_tp), + SEC_DEF("raw_tp+", RAW_TRACEPOINT, 0, SEC_NONE, attach_raw_tp), + SEC_DEF("raw_tracepoint.w+", RAW_TRACEPOINT_WRITABLE, 0, SEC_NONE, attach_raw_tp), + SEC_DEF("raw_tp.w+", RAW_TRACEPOINT_WRITABLE, 0, SEC_NONE, attach_raw_tp), + SEC_DEF("tp_btf+", TRACING, BPF_TRACE_RAW_TP, SEC_ATTACH_BTF, attach_trace), + SEC_DEF("fentry+", TRACING, BPF_TRACE_FENTRY, SEC_ATTACH_BTF, attach_trace), + SEC_DEF("fmod_ret+", TRACING, BPF_MODIFY_RETURN, SEC_ATTACH_BTF, attach_trace), + SEC_DEF("fexit+", TRACING, BPF_TRACE_FEXIT, SEC_ATTACH_BTF, attach_trace), + SEC_DEF("fentry.s+", TRACING, BPF_TRACE_FENTRY, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace), + SEC_DEF("fmod_ret.s+", TRACING, BPF_MODIFY_RETURN, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace), + SEC_DEF("fexit.s+", TRACING, BPF_TRACE_FEXIT, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace), + SEC_DEF("freplace+", EXT, 0, SEC_ATTACH_BTF, attach_trace), + SEC_DEF("lsm+", LSM, BPF_LSM_MAC, SEC_ATTACH_BTF, attach_lsm), + SEC_DEF("lsm.s+", LSM, BPF_LSM_MAC, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_lsm), + SEC_DEF("lsm_cgroup+", LSM, BPF_LSM_CGROUP, SEC_ATTACH_BTF), + SEC_DEF("iter+", TRACING, BPF_TRACE_ITER, SEC_ATTACH_BTF, attach_iter), + SEC_DEF("iter.s+", TRACING, BPF_TRACE_ITER, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_iter), + SEC_DEF("syscall", SYSCALL, 0, SEC_SLEEPABLE), + SEC_DEF("xdp.frags/devmap", XDP, BPF_XDP_DEVMAP, SEC_XDP_FRAGS), + SEC_DEF("xdp/devmap", XDP, BPF_XDP_DEVMAP, SEC_ATTACHABLE), + SEC_DEF("xdp.frags/cpumap", XDP, BPF_XDP_CPUMAP, SEC_XDP_FRAGS), + SEC_DEF("xdp/cpumap", XDP, BPF_XDP_CPUMAP, SEC_ATTACHABLE), + SEC_DEF("xdp.frags", XDP, BPF_XDP, SEC_XDP_FRAGS), + SEC_DEF("xdp", XDP, BPF_XDP, SEC_ATTACHABLE_OPT), + SEC_DEF("perf_event", PERF_EVENT, 0, SEC_NONE), + SEC_DEF("lwt_in", LWT_IN, 0, SEC_NONE), + SEC_DEF("lwt_out", LWT_OUT, 0, SEC_NONE), + SEC_DEF("lwt_xmit", LWT_XMIT, 0, SEC_NONE), + SEC_DEF("lwt_seg6local", LWT_SEG6LOCAL, 0, SEC_NONE), + SEC_DEF("sockops", SOCK_OPS, BPF_CGROUP_SOCK_OPS, SEC_ATTACHABLE_OPT), + SEC_DEF("sk_skb/stream_parser", SK_SKB, BPF_SK_SKB_STREAM_PARSER, SEC_ATTACHABLE_OPT), + SEC_DEF("sk_skb/stream_verdict",SK_SKB, BPF_SK_SKB_STREAM_VERDICT, SEC_ATTACHABLE_OPT), + SEC_DEF("sk_skb", SK_SKB, 0, SEC_NONE), + SEC_DEF("sk_msg", SK_MSG, BPF_SK_MSG_VERDICT, SEC_ATTACHABLE_OPT), + SEC_DEF("lirc_mode2", LIRC_MODE2, BPF_LIRC_MODE2, SEC_ATTACHABLE_OPT), + SEC_DEF("flow_dissector", FLOW_DISSECTOR, BPF_FLOW_DISSECTOR, SEC_ATTACHABLE_OPT), + SEC_DEF("cgroup_skb/ingress", CGROUP_SKB, BPF_CGROUP_INET_INGRESS, SEC_ATTACHABLE_OPT), + SEC_DEF("cgroup_skb/egress", CGROUP_SKB, BPF_CGROUP_INET_EGRESS, SEC_ATTACHABLE_OPT), + SEC_DEF("cgroup/skb", CGROUP_SKB, 0, SEC_NONE), + SEC_DEF("cgroup/sock_create", CGROUP_SOCK, BPF_CGROUP_INET_SOCK_CREATE, SEC_ATTACHABLE), + SEC_DEF("cgroup/sock_release", CGROUP_SOCK, BPF_CGROUP_INET_SOCK_RELEASE, SEC_ATTACHABLE), + SEC_DEF("cgroup/sock", CGROUP_SOCK, BPF_CGROUP_INET_SOCK_CREATE, SEC_ATTACHABLE_OPT), + SEC_DEF("cgroup/post_bind4", CGROUP_SOCK, BPF_CGROUP_INET4_POST_BIND, SEC_ATTACHABLE), + SEC_DEF("cgroup/post_bind6", CGROUP_SOCK, BPF_CGROUP_INET6_POST_BIND, SEC_ATTACHABLE), + SEC_DEF("cgroup/bind4", CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_BIND, SEC_ATTACHABLE), + SEC_DEF("cgroup/bind6", CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_BIND, SEC_ATTACHABLE), + SEC_DEF("cgroup/connect4", CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_CONNECT, SEC_ATTACHABLE), + SEC_DEF("cgroup/connect6", CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_CONNECT, SEC_ATTACHABLE), + SEC_DEF("cgroup/sendmsg4", CGROUP_SOCK_ADDR, BPF_CGROUP_UDP4_SENDMSG, SEC_ATTACHABLE), + SEC_DEF("cgroup/sendmsg6", CGROUP_SOCK_ADDR, BPF_CGROUP_UDP6_SENDMSG, SEC_ATTACHABLE), + SEC_DEF("cgroup/recvmsg4", CGROUP_SOCK_ADDR, BPF_CGROUP_UDP4_RECVMSG, SEC_ATTACHABLE), + SEC_DEF("cgroup/recvmsg6", CGROUP_SOCK_ADDR, BPF_CGROUP_UDP6_RECVMSG, SEC_ATTACHABLE), + SEC_DEF("cgroup/getpeername4", CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_GETPEERNAME, SEC_ATTACHABLE), + SEC_DEF("cgroup/getpeername6", CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_GETPEERNAME, SEC_ATTACHABLE), + SEC_DEF("cgroup/getsockname4", CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_GETSOCKNAME, SEC_ATTACHABLE), + SEC_DEF("cgroup/getsockname6", CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_GETSOCKNAME, SEC_ATTACHABLE), + SEC_DEF("cgroup/sysctl", CGROUP_SYSCTL, BPF_CGROUP_SYSCTL, SEC_ATTACHABLE), + SEC_DEF("cgroup/getsockopt", CGROUP_SOCKOPT, BPF_CGROUP_GETSOCKOPT, SEC_ATTACHABLE), + SEC_DEF("cgroup/setsockopt", CGROUP_SOCKOPT, BPF_CGROUP_SETSOCKOPT, SEC_ATTACHABLE), + SEC_DEF("cgroup/dev", CGROUP_DEVICE, BPF_CGROUP_DEVICE, SEC_ATTACHABLE_OPT), + SEC_DEF("struct_ops+", STRUCT_OPS, 0, SEC_NONE), + SEC_DEF("sk_lookup", SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE), +}; + +static size_t custom_sec_def_cnt; +static struct bpf_sec_def *custom_sec_defs; +static struct bpf_sec_def custom_fallback_def; +static bool has_custom_fallback_def; + +static int last_custom_sec_def_handler_id; + +int libbpf_register_prog_handler(const char *sec, + enum bpf_prog_type prog_type, + enum bpf_attach_type exp_attach_type, + const struct libbpf_prog_handler_opts *opts) +{ + struct bpf_sec_def *sec_def; + + if (!OPTS_VALID(opts, libbpf_prog_handler_opts)) + return libbpf_err(-EINVAL); + + if (last_custom_sec_def_handler_id == INT_MAX) /* prevent overflow */ + return libbpf_err(-E2BIG); + + if (sec) { + sec_def = libbpf_reallocarray(custom_sec_defs, custom_sec_def_cnt + 1, + sizeof(*sec_def)); + if (!sec_def) + return libbpf_err(-ENOMEM); + + custom_sec_defs = sec_def; + sec_def = &custom_sec_defs[custom_sec_def_cnt]; + } else { + if (has_custom_fallback_def) + return libbpf_err(-EBUSY); + + sec_def = &custom_fallback_def; + } + + sec_def->sec = sec ? strdup(sec) : NULL; + if (sec && !sec_def->sec) + return libbpf_err(-ENOMEM); + + sec_def->prog_type = prog_type; + sec_def->expected_attach_type = exp_attach_type; + sec_def->cookie = OPTS_GET(opts, cookie, 0); + + sec_def->prog_setup_fn = OPTS_GET(opts, prog_setup_fn, NULL); + sec_def->prog_prepare_load_fn = OPTS_GET(opts, prog_prepare_load_fn, NULL); + sec_def->prog_attach_fn = OPTS_GET(opts, prog_attach_fn, NULL); + + sec_def->handler_id = ++last_custom_sec_def_handler_id; + + if (sec) + custom_sec_def_cnt++; + else + has_custom_fallback_def = true; + + return sec_def->handler_id; +} + +int libbpf_unregister_prog_handler(int handler_id) +{ + struct bpf_sec_def *sec_defs; + int i; + + if (handler_id <= 0) + return libbpf_err(-EINVAL); + + if (has_custom_fallback_def && custom_fallback_def.handler_id == handler_id) { + memset(&custom_fallback_def, 0, sizeof(custom_fallback_def)); + has_custom_fallback_def = false; + return 0; + } + + for (i = 0; i < custom_sec_def_cnt; i++) { + if (custom_sec_defs[i].handler_id == handler_id) + break; + } + + if (i == custom_sec_def_cnt) + return libbpf_err(-ENOENT); + + free(custom_sec_defs[i].sec); + for (i = i + 1; i < custom_sec_def_cnt; i++) + custom_sec_defs[i - 1] = custom_sec_defs[i]; + custom_sec_def_cnt--; + + /* try to shrink the array, but it's ok if we couldn't */ + sec_defs = libbpf_reallocarray(custom_sec_defs, custom_sec_def_cnt, sizeof(*sec_defs)); + if (sec_defs) + custom_sec_defs = sec_defs; + + return 0; +} + +static bool sec_def_matches(const struct bpf_sec_def *sec_def, const char *sec_name) +{ + size_t len = strlen(sec_def->sec); + + /* "type/" always has to have proper SEC("type/extras") form */ + if (sec_def->sec[len - 1] == '/') { + if (str_has_pfx(sec_name, sec_def->sec)) + return true; + return false; + } + + /* "type+" means it can be either exact SEC("type") or + * well-formed SEC("type/extras") with proper '/' separator + */ + if (sec_def->sec[len - 1] == '+') { + len--; + /* not even a prefix */ + if (strncmp(sec_name, sec_def->sec, len) != 0) + return false; + /* exact match or has '/' separator */ + if (sec_name[len] == '\0' || sec_name[len] == '/') + return true; + return false; + } + + return strcmp(sec_name, sec_def->sec) == 0; +} + +static const struct bpf_sec_def *find_sec_def(const char *sec_name) +{ + const struct bpf_sec_def *sec_def; + int i, n; + + n = custom_sec_def_cnt; + for (i = 0; i < n; i++) { + sec_def = &custom_sec_defs[i]; + if (sec_def_matches(sec_def, sec_name)) + return sec_def; + } + + n = ARRAY_SIZE(section_defs); + for (i = 0; i < n; i++) { + sec_def = §ion_defs[i]; + if (sec_def_matches(sec_def, sec_name)) + return sec_def; + } + + if (has_custom_fallback_def) + return &custom_fallback_def; + + return NULL; +} + +#define MAX_TYPE_NAME_SIZE 32 + +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++) { + const struct bpf_sec_def *sec_def = §ion_defs[i]; + + if (attach_type) { + if (sec_def->prog_prepare_load_fn != libbpf_prepare_prog_load) + continue; + + if (!(sec_def->cookie & SEC_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 libbpf_err(-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 libbpf_err(-ESRCH); +} + +const char *libbpf_bpf_attach_type_str(enum bpf_attach_type t) +{ + if (t < 0 || t >= ARRAY_SIZE(attach_type_name)) + return NULL; + + return attach_type_name[t]; +} + +const char *libbpf_bpf_link_type_str(enum bpf_link_type t) +{ + if (t < 0 || t >= ARRAY_SIZE(link_type_name)) + return NULL; + + return link_type_name[t]; +} + +const char *libbpf_bpf_map_type_str(enum bpf_map_type t) +{ + if (t < 0 || t >= ARRAY_SIZE(map_type_name)) + return NULL; + + return map_type_name[t]; +} + +const char *libbpf_bpf_prog_type_str(enum bpf_prog_type t) +{ + if (t < 0 || t >= ARRAY_SIZE(prog_type_name)) + return NULL; + + return prog_type_name[t]; +} + +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, + Elf64_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; + unsigned int moff, insn_idx; + const char *name; + __u32 member_idx; + Elf64_Sym *sym; + Elf64_Rel *rel; + int i, nrels; + + btf = obj->btf; + nrels = shdr->sh_size / shdr->sh_entsize; + for (i = 0; i < nrels; i++) { + rel = elf_rel_by_idx(data, i); + if (!rel) { + pr_warn("struct_ops reloc: failed to get %d reloc\n", i); + return -LIBBPF_ERRNO__FORMAT; + } + + sym = elf_sym_by_idx(obj, ELF64_R_SYM(rel->r_info)); + if (!sym) { + pr_warn("struct_ops reloc: symbol %zx not found\n", + (size_t)ELF64_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; + } + + /* prevent the use of BPF prog with invalid type */ + if (prog->type != BPF_PROG_TYPE_STRUCT_OPS) { + pr_warn("struct_ops reloc %s: prog %s is not struct_ops BPF program\n", + map->name, prog->name); + return -EINVAL; + } + + /* if we haven't yet processed this BPF program, record proper + * attach_btf_id and member_idx + */ + if (!prog->attach_btf_id) { + prog->attach_btf_id = st_ops->type_id; + prog->expected_attach_type = member_idx; + } + + /* struct_ops BPF prog can be re-used between multiple + * .struct_ops as long as it's the same struct_ops struct + * definition and the same function pointer field + */ + if (prog->attach_btf_id != st_ops->type_id || + prog->expected_attach_type != member_idx) { + 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; + } + + st_ops->progs[member_idx] = prog; + } + + return 0; +} + +#define BTF_TRACE_PREFIX "btf_trace_" +#define BTF_LSM_PREFIX "bpf_lsm_" +#define BTF_ITER_PREFIX "bpf_iter_" +#define BTF_MAX_NAME_SIZE 128 + +void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type, + const char **prefix, int *kind) +{ + switch (attach_type) { + case BPF_TRACE_RAW_TP: + *prefix = BTF_TRACE_PREFIX; + *kind = BTF_KIND_TYPEDEF; + break; + case BPF_LSM_MAC: + case BPF_LSM_CGROUP: + *prefix = BTF_LSM_PREFIX; + *kind = BTF_KIND_FUNC; + break; + case BPF_TRACE_ITER: + *prefix = BTF_ITER_PREFIX; + *kind = BTF_KIND_FUNC; + break; + default: + *prefix = ""; + *kind = BTF_KIND_FUNC; + } +} + +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 + * 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_attach_btf_id(struct btf *btf, const char *name, + enum bpf_attach_type attach_type) +{ + const char *prefix; + int kind; + + btf_get_kernel_prefix_kind(attach_type, &prefix, &kind); + return find_btf_by_prefix_kind(btf, prefix, name, kind); +} + +int libbpf_find_vmlinux_btf_id(const char *name, + enum bpf_attach_type attach_type) +{ + struct btf *btf; + int err; + + btf = btf__load_vmlinux_btf(); + err = libbpf_get_error(btf); + if (err) { + pr_warn("vmlinux BTF is not found\n"); + return libbpf_err(err); + } + + err = find_attach_btf_id(btf, name, attach_type); + if (err <= 0) + pr_warn("%s is not found in vmlinux BTF\n", name); + + btf__free(btf); + return libbpf_err(err); +} + +static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd) +{ + struct bpf_prog_info info; + __u32 info_len = sizeof(info); + struct btf *btf; + int err; + + memset(&info, 0, info_len); + err = bpf_obj_get_info_by_fd(attach_prog_fd, &info, &info_len); + if (err) { + pr_warn("failed bpf_obj_get_info_by_fd for FD %d: %d\n", + attach_prog_fd, err); + return err; + } + + err = -EINVAL; + if (!info.btf_id) { + pr_warn("The target program doesn't have BTF\n"); + goto out; + } + btf = btf__load_from_kernel_by_id(info.btf_id); + err = libbpf_get_error(btf); + if (err) { + pr_warn("Failed to get BTF %d of the program: %d\n", info.btf_id, err); + 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: + return err; +} + +static int find_kernel_btf_id(struct bpf_object *obj, const char *attach_name, + enum bpf_attach_type attach_type, + int *btf_obj_fd, int *btf_type_id) +{ + int ret, i; + + ret = find_attach_btf_id(obj->btf_vmlinux, attach_name, attach_type); + if (ret > 0) { + *btf_obj_fd = 0; /* vmlinux BTF */ + *btf_type_id = ret; + return 0; + } + if (ret != -ENOENT) + return ret; + + ret = load_module_btfs(obj); + if (ret) + return ret; + + for (i = 0; i < obj->btf_module_cnt; i++) { + const struct module_btf *mod = &obj->btf_modules[i]; + + ret = find_attach_btf_id(mod->btf, attach_name, attach_type); + if (ret > 0) { + *btf_obj_fd = mod->fd; + *btf_type_id = ret; + return 0; + } + if (ret == -ENOENT) + continue; + + return ret; + } + + return -ESRCH; +} + +static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attach_name, + int *btf_obj_fd, int *btf_type_id) +{ + enum bpf_attach_type attach_type = prog->expected_attach_type; + __u32 attach_prog_fd = prog->attach_prog_fd; + int err = 0; + + /* BPF program's BTF ID */ + if (prog->type == BPF_PROG_TYPE_EXT || attach_prog_fd) { + if (!attach_prog_fd) { + pr_warn("prog '%s': attach program FD is not set\n", prog->name); + return -EINVAL; + } + err = libbpf_find_prog_btf_id(attach_name, attach_prog_fd); + if (err < 0) { + pr_warn("prog '%s': failed to find BPF program (FD %d) BTF ID for '%s': %d\n", + prog->name, attach_prog_fd, attach_name, err); + return err; + } + *btf_obj_fd = 0; + *btf_type_id = err; + return 0; + } + + /* kernel/module BTF ID */ + if (prog->obj->gen_loader) { + bpf_gen__record_attach_target(prog->obj->gen_loader, attach_name, attach_type); + *btf_obj_fd = 0; + *btf_type_id = 1; + } else { + err = find_kernel_btf_id(prog->obj, attach_name, attach_type, btf_obj_fd, btf_type_id); + } + if (err) { + pr_warn("prog '%s': failed to find kernel BTF type ID of '%s': %d\n", + prog->name, attach_name, err); + return err; + } + return 0; +} + +int libbpf_attach_type_by_name(const char *name, + enum bpf_attach_type *attach_type) +{ + char *type_names; + const struct bpf_sec_def *sec_def; + + if (!name) + return libbpf_err(-EINVAL); + + sec_def = find_sec_def(name); + if (!sec_def) { + 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 libbpf_err(-EINVAL); + } + + if (sec_def->prog_prepare_load_fn != libbpf_prepare_prog_load) + return libbpf_err(-EINVAL); + if (!(sec_def->cookie & SEC_ATTACHABLE)) + return libbpf_err(-EINVAL); + + *attach_type = sec_def->expected_attach_type; + return 0; +} + +int bpf_map__fd(const struct bpf_map *map) +{ + return map ? map->fd : libbpf_err(-EINVAL); +} + +static bool map_uses_real_name(const struct bpf_map *map) +{ + /* Since libbpf started to support custom .data.* and .rodata.* maps, + * their user-visible name differs from kernel-visible name. Users see + * such map's corresponding ELF section name as a map name. + * This check distinguishes .data/.rodata from .data.* and .rodata.* + * maps to know which name has to be returned to the user. + */ + if (map->libbpf_type == LIBBPF_MAP_DATA && strcmp(map->real_name, DATA_SEC) != 0) + return true; + if (map->libbpf_type == LIBBPF_MAP_RODATA && strcmp(map->real_name, RODATA_SEC) != 0) + return true; + return false; +} + +const char *bpf_map__name(const struct bpf_map *map) +{ + if (!map) + return NULL; + + if (map_uses_real_name(map)) + return map->real_name; + + return map->name; +} + +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 libbpf_err(-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 libbpf_err(-EBUSY); + map->def.map_flags = flags; + return 0; +} + +__u64 bpf_map__map_extra(const struct bpf_map *map) +{ + return map->map_extra; +} + +int bpf_map__set_map_extra(struct bpf_map *map, __u64 map_extra) +{ + if (map->fd >= 0) + return libbpf_err(-EBUSY); + map->map_extra = map_extra; + 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 libbpf_err(-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 libbpf_err(-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 libbpf_err(-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_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 libbpf_err(-EINVAL); + + memcpy(map->mmaped, data, size); + return 0; +} + +const void *bpf_map__initial_value(struct bpf_map *map, size_t *psize) +{ + if (!map->mmaped) + return NULL; + *psize = map->def.value_size; + return map->mmaped; +} + +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 libbpf_err(-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 libbpf_err(-EINVAL); + } + if (map->inner_map_fd != -1) { + pr_warn("error: inner_map_fd already specified\n"); + return libbpf_err(-EINVAL); + } + if (map->inner_map) { + bpf_map__destroy(map->inner_map); + zfree(&map->inner_map); + } + 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 errno = EINVAL, 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 errno = EINVAL, NULL; + } + + idx = (m - obj->maps) + i; + if (idx >= obj->nr_maps || idx < 0) + return NULL; + return &obj->maps[idx]; +} + +struct bpf_map * +bpf_object__next_map(const struct bpf_object *obj, const struct bpf_map *prev) +{ + if (prev == NULL) + return obj->maps; + + return __bpf_map__iter(prev, obj, 1); +} + +struct bpf_map * +bpf_object__prev_map(const struct bpf_object *obj, const struct bpf_map *next) +{ + 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 it's a special internal map name (which always starts + * with dot) then check if that special name matches the + * real map name (ELF section name) + */ + if (name[0] == '.') { + if (pos->real_name && strcmp(pos->real_name, name) == 0) + return pos; + continue; + } + /* otherwise map name has to be an exact match */ + if (map_uses_real_name(pos)) { + if (strcmp(pos->real_name, name) == 0) + return pos; + continue; + } + if (strcmp(pos->name, name) == 0) + return pos; + } + return errno = ENOENT, 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)); +} + +static int validate_map_op(const struct bpf_map *map, size_t key_sz, + size_t value_sz, bool check_value_sz) +{ + if (map->fd <= 0) + return -ENOENT; + + if (map->def.key_size != key_sz) { + pr_warn("map '%s': unexpected key size %zu provided, expected %u\n", + map->name, key_sz, map->def.key_size); + return -EINVAL; + } + + if (!check_value_sz) + return 0; + + switch (map->def.type) { + case BPF_MAP_TYPE_PERCPU_ARRAY: + case BPF_MAP_TYPE_PERCPU_HASH: + case BPF_MAP_TYPE_LRU_PERCPU_HASH: + case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE: { + int num_cpu = libbpf_num_possible_cpus(); + size_t elem_sz = roundup(map->def.value_size, 8); + + if (value_sz != num_cpu * elem_sz) { + pr_warn("map '%s': unexpected value size %zu provided for per-CPU map, expected %d * %zu = %zd\n", + map->name, value_sz, num_cpu, elem_sz, num_cpu * elem_sz); + return -EINVAL; + } + break; + } + default: + if (map->def.value_size != value_sz) { + pr_warn("map '%s': unexpected value size %zu provided, expected %u\n", + map->name, value_sz, map->def.value_size); + return -EINVAL; + } + break; + } + return 0; +} + +int bpf_map__lookup_elem(const struct bpf_map *map, + const void *key, size_t key_sz, + void *value, size_t value_sz, __u64 flags) +{ + int err; + + err = validate_map_op(map, key_sz, value_sz, true); + if (err) + return libbpf_err(err); + + return bpf_map_lookup_elem_flags(map->fd, key, value, flags); +} + +int bpf_map__update_elem(const struct bpf_map *map, + const void *key, size_t key_sz, + const void *value, size_t value_sz, __u64 flags) +{ + int err; + + err = validate_map_op(map, key_sz, value_sz, true); + if (err) + return libbpf_err(err); + + return bpf_map_update_elem(map->fd, key, value, flags); +} + +int bpf_map__delete_elem(const struct bpf_map *map, + const void *key, size_t key_sz, __u64 flags) +{ + int err; + + err = validate_map_op(map, key_sz, 0, false /* check_value_sz */); + if (err) + return libbpf_err(err); + + return bpf_map_delete_elem_flags(map->fd, key, flags); +} + +int bpf_map__lookup_and_delete_elem(const struct bpf_map *map, + const void *key, size_t key_sz, + void *value, size_t value_sz, __u64 flags) +{ + int err; + + err = validate_map_op(map, key_sz, value_sz, true); + if (err) + return libbpf_err(err); + + return bpf_map_lookup_and_delete_elem_flags(map->fd, key, value, flags); +} + +int bpf_map__get_next_key(const struct bpf_map *map, + const void *cur_key, void *next_key, size_t key_sz) +{ + int err; + + err = validate_map_op(map, key_sz, 0, false /* check_value_sz */); + if (err) + return libbpf_err(err); + + return bpf_map_get_next_key(map->fd, cur_key, next_key); +} + +long libbpf_get_error(const void *ptr) +{ + if (!IS_ERR_OR_NULL(ptr)) + return 0; + + if (IS_ERR(ptr)) + errno = -PTR_ERR(ptr); + + /* If ptr == NULL, then errno should be already set by the failing + * API, because libbpf never returns NULL on success and it now always + * sets errno on error. So no extra errno handling for ptr == NULL + * case. + */ + return -errno; +} + +/* Replace link's underlying BPF program with the new one */ +int bpf_link__update_program(struct bpf_link *link, struct bpf_program *prog) +{ + int ret; + + ret = bpf_link_update(bpf_link__fd(link), bpf_program__fd(prog), NULL); + return libbpf_err_errno(ret); +} + +/* 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->pin_path) + free(link->pin_path); + if (link->dealloc) + link->dealloc(link); + else + free(link); + + return libbpf_err(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 libbpf_err_errno(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 libbpf_err_ptr(fd); + } + + link = calloc(1, sizeof(*link)); + if (!link) { + close(fd); + return libbpf_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 libbpf_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 libbpf_err(-EBUSY); + err = make_parent_dir(path); + if (err) + return libbpf_err(err); + err = check_path(path); + if (err) + return libbpf_err(err); + + link->pin_path = strdup(path); + if (!link->pin_path) + return libbpf_err(-ENOMEM); + + if (bpf_obj_pin(link->fd, link->pin_path)) { + err = -errno; + zfree(&link->pin_path); + return libbpf_err(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 libbpf_err(-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; +} + +struct bpf_link_perf { + struct bpf_link link; + int perf_event_fd; + /* legacy kprobe support: keep track of probe identifier and type */ + char *legacy_probe_name; + bool legacy_is_kprobe; + bool legacy_is_retprobe; +}; + +static int remove_kprobe_event_legacy(const char *probe_name, bool retprobe); +static int remove_uprobe_event_legacy(const char *probe_name, bool retprobe); + +static int bpf_link_perf_detach(struct bpf_link *link) +{ + struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link); + int err = 0; + + if (ioctl(perf_link->perf_event_fd, PERF_EVENT_IOC_DISABLE, 0) < 0) + err = -errno; + + if (perf_link->perf_event_fd != link->fd) + close(perf_link->perf_event_fd); + close(link->fd); + + /* legacy uprobe/kprobe needs to be removed after perf event fd closure */ + if (perf_link->legacy_probe_name) { + if (perf_link->legacy_is_kprobe) { + err = remove_kprobe_event_legacy(perf_link->legacy_probe_name, + perf_link->legacy_is_retprobe); + } else { + err = remove_uprobe_event_legacy(perf_link->legacy_probe_name, + perf_link->legacy_is_retprobe); + } + } + + return err; +} + +static void bpf_link_perf_dealloc(struct bpf_link *link) +{ + struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link); + + free(perf_link->legacy_probe_name); + free(perf_link); +} + +struct bpf_link *bpf_program__attach_perf_event_opts(const struct bpf_program *prog, int pfd, + const struct bpf_perf_event_opts *opts) +{ + char errmsg[STRERR_BUFSIZE]; + struct bpf_link_perf *link; + int prog_fd, link_fd = -1, err; + + if (!OPTS_VALID(opts, bpf_perf_event_opts)) + return libbpf_err_ptr(-EINVAL); + + if (pfd < 0) { + pr_warn("prog '%s': invalid perf event FD %d\n", + prog->name, pfd); + return libbpf_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 libbpf_err_ptr(-EINVAL); + } + + link = calloc(1, sizeof(*link)); + if (!link) + return libbpf_err_ptr(-ENOMEM); + link->link.detach = &bpf_link_perf_detach; + link->link.dealloc = &bpf_link_perf_dealloc; + link->perf_event_fd = pfd; + + if (kernel_supports(prog->obj, FEAT_PERF_LINK)) { + DECLARE_LIBBPF_OPTS(bpf_link_create_opts, link_opts, + .perf_event.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0)); + + link_fd = bpf_link_create(prog_fd, pfd, BPF_PERF_EVENT, &link_opts); + if (link_fd < 0) { + err = -errno; + pr_warn("prog '%s': failed to create BPF link for perf_event FD %d: %d (%s)\n", + prog->name, pfd, + err, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + goto err_out; + } + link->link.fd = link_fd; + } else { + if (OPTS_GET(opts, bpf_cookie, 0)) { + pr_warn("prog '%s': user context value is not supported\n", prog->name); + err = -EOPNOTSUPP; + goto err_out; + } + + if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, prog_fd) < 0) { + err = -errno; + pr_warn("prog '%s': failed to attach to perf_event FD %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); + goto err_out; + } + link->link.fd = pfd; + } + if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) { + err = -errno; + pr_warn("prog '%s': failed to enable perf_event FD %d: %s\n", + prog->name, pfd, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + goto err_out; + } + + return &link->link; +err_out: + if (link_fd >= 0) + close(link_fd); + free(link); + return libbpf_err_ptr(err); +} + +struct bpf_link *bpf_program__attach_perf_event(const struct bpf_program *prog, int pfd) +{ + return bpf_program__attach_perf_event_opts(prog, pfd, NULL); +} + +/* + * 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"); +} + +#define PERF_UPROBE_REF_CTR_OFFSET_BITS 32 +#define PERF_UPROBE_REF_CTR_OFFSET_SHIFT 32 + +static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name, + uint64_t offset, int pid, size_t ref_ctr_off) +{ + const size_t attr_sz = sizeof(struct perf_event_attr); + struct perf_event_attr attr; + char errmsg[STRERR_BUFSIZE]; + int type, pfd; + + if ((__u64)ref_ctr_off >= (1ULL << PERF_UPROBE_REF_CTR_OFFSET_BITS)) + return -EINVAL; + + memset(&attr, 0, attr_sz); + + 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 = attr_sz; + attr.type = type; + attr.config |= (__u64)ref_ctr_off << PERF_UPROBE_REF_CTR_OFFSET_SHIFT; + 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); + return pfd >= 0 ? pfd : -errno; +} + +static int append_to_file(const char *file, const char *fmt, ...) +{ + int fd, n, err = 0; + va_list ap; + + fd = open(file, O_WRONLY | O_APPEND | O_CLOEXEC, 0); + if (fd < 0) + return -errno; + + va_start(ap, fmt); + n = vdprintf(fd, fmt, ap); + va_end(ap); + + if (n < 0) + err = -errno; + + close(fd); + return err; +} + +#define DEBUGFS "/sys/kernel/debug/tracing" +#define TRACEFS "/sys/kernel/tracing" + +static bool use_debugfs(void) +{ + static int has_debugfs = -1; + + if (has_debugfs < 0) + has_debugfs = faccessat(AT_FDCWD, DEBUGFS, F_OK, AT_EACCESS) == 0; + + return has_debugfs == 1; +} + +static const char *tracefs_path(void) +{ + return use_debugfs() ? DEBUGFS : TRACEFS; +} + +static const char *tracefs_kprobe_events(void) +{ + return use_debugfs() ? DEBUGFS"/kprobe_events" : TRACEFS"/kprobe_events"; +} + +static const char *tracefs_uprobe_events(void) +{ + return use_debugfs() ? DEBUGFS"/uprobe_events" : TRACEFS"/uprobe_events"; +} + +static void gen_kprobe_legacy_event_name(char *buf, size_t buf_sz, + const char *kfunc_name, size_t offset) +{ + static int index = 0; + + snprintf(buf, buf_sz, "libbpf_%u_%s_0x%zx_%d", getpid(), kfunc_name, offset, + __sync_fetch_and_add(&index, 1)); +} + +static int add_kprobe_event_legacy(const char *probe_name, bool retprobe, + const char *kfunc_name, size_t offset) +{ + return append_to_file(tracefs_kprobe_events(), "%c:%s/%s %s+0x%zx", + retprobe ? 'r' : 'p', + retprobe ? "kretprobes" : "kprobes", + probe_name, kfunc_name, offset); +} + +static int remove_kprobe_event_legacy(const char *probe_name, bool retprobe) +{ + return append_to_file(tracefs_kprobe_events(), "-:%s/%s", + retprobe ? "kretprobes" : "kprobes", probe_name); +} + +static int determine_kprobe_perf_type_legacy(const char *probe_name, bool retprobe) +{ + char file[256]; + + snprintf(file, sizeof(file), "%s/events/%s/%s/id", + tracefs_path(), retprobe ? "kretprobes" : "kprobes", probe_name); + + return parse_uint_from_file(file, "%d\n"); +} + +static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe, + const char *kfunc_name, size_t offset, int pid) +{ + const size_t attr_sz = sizeof(struct perf_event_attr); + struct perf_event_attr attr; + char errmsg[STRERR_BUFSIZE]; + int type, pfd, err; + + err = add_kprobe_event_legacy(probe_name, retprobe, kfunc_name, offset); + if (err < 0) { + pr_warn("failed to add legacy kprobe event for '%s+0x%zx': %s\n", + kfunc_name, offset, + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + return err; + } + type = determine_kprobe_perf_type_legacy(probe_name, retprobe); + if (type < 0) { + err = type; + pr_warn("failed to determine legacy kprobe event id for '%s+0x%zx': %s\n", + kfunc_name, offset, + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + goto err_clean_legacy; + } + + memset(&attr, 0, attr_sz); + attr.size = attr_sz; + attr.config = type; + attr.type = PERF_TYPE_TRACEPOINT; + + 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("legacy kprobe perf_event_open() failed: %s\n", + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + goto err_clean_legacy; + } + return pfd; + +err_clean_legacy: + /* Clear the newly added legacy kprobe_event */ + remove_kprobe_event_legacy(probe_name, retprobe); + return err; +} + +static const char *arch_specific_syscall_pfx(void) +{ +#if defined(__x86_64__) + return "x64"; +#elif defined(__i386__) + return "ia32"; +#elif defined(__s390x__) + return "s390x"; +#elif defined(__s390__) + return "s390"; +#elif defined(__arm__) + return "arm"; +#elif defined(__aarch64__) + return "arm64"; +#elif defined(__mips__) + return "mips"; +#elif defined(__riscv) + return "riscv"; +#elif defined(__powerpc__) + return "powerpc"; +#elif defined(__powerpc64__) + return "powerpc64"; +#else + return NULL; +#endif +} + +static int probe_kern_syscall_wrapper(void) +{ + char syscall_name[64]; + const char *ksys_pfx; + + ksys_pfx = arch_specific_syscall_pfx(); + if (!ksys_pfx) + return 0; + + snprintf(syscall_name, sizeof(syscall_name), "__%s_sys_bpf", ksys_pfx); + + if (determine_kprobe_perf_type() >= 0) { + int pfd; + + pfd = perf_event_open_probe(false, false, syscall_name, 0, getpid(), 0); + if (pfd >= 0) + close(pfd); + + return pfd >= 0 ? 1 : 0; + } else { /* legacy mode */ + char probe_name[128]; + + gen_kprobe_legacy_event_name(probe_name, sizeof(probe_name), syscall_name, 0); + if (add_kprobe_event_legacy(probe_name, false, syscall_name, 0) < 0) + return 0; + + (void)remove_kprobe_event_legacy(probe_name, false); + return 1; + } +} + +struct bpf_link * +bpf_program__attach_kprobe_opts(const struct bpf_program *prog, + const char *func_name, + const struct bpf_kprobe_opts *opts) +{ + DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts); + char errmsg[STRERR_BUFSIZE]; + char *legacy_probe = NULL; + struct bpf_link *link; + size_t offset; + bool retprobe, legacy; + int pfd, err; + + if (!OPTS_VALID(opts, bpf_kprobe_opts)) + return libbpf_err_ptr(-EINVAL); + + retprobe = OPTS_GET(opts, retprobe, false); + offset = OPTS_GET(opts, offset, 0); + pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0); + + legacy = determine_kprobe_perf_type() < 0; + if (!legacy) { + pfd = perf_event_open_probe(false /* uprobe */, retprobe, + func_name, offset, + -1 /* pid */, 0 /* ref_ctr_off */); + } else { + char probe_name[256]; + + gen_kprobe_legacy_event_name(probe_name, sizeof(probe_name), + func_name, offset); + + legacy_probe = strdup(probe_name); + if (!legacy_probe) + return libbpf_err_ptr(-ENOMEM); + + pfd = perf_event_kprobe_open_legacy(legacy_probe, retprobe, func_name, + offset, -1 /* pid */); + } + if (pfd < 0) { + err = -errno; + pr_warn("prog '%s': failed to create %s '%s+0x%zx' perf event: %s\n", + prog->name, retprobe ? "kretprobe" : "kprobe", + func_name, offset, + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + goto err_out; + } + link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts); + err = libbpf_get_error(link); + if (err) { + close(pfd); + pr_warn("prog '%s': failed to attach to %s '%s+0x%zx': %s\n", + prog->name, retprobe ? "kretprobe" : "kprobe", + func_name, offset, + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + goto err_clean_legacy; + } + if (legacy) { + struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link); + + perf_link->legacy_probe_name = legacy_probe; + perf_link->legacy_is_kprobe = true; + perf_link->legacy_is_retprobe = retprobe; + } + + return link; + +err_clean_legacy: + if (legacy) + remove_kprobe_event_legacy(legacy_probe, retprobe); +err_out: + free(legacy_probe); + return libbpf_err_ptr(err); +} + +struct bpf_link *bpf_program__attach_kprobe(const struct bpf_program *prog, + bool retprobe, + const char *func_name) +{ + DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts, + .retprobe = retprobe, + ); + + return bpf_program__attach_kprobe_opts(prog, func_name, &opts); +} + +struct bpf_link *bpf_program__attach_ksyscall(const struct bpf_program *prog, + const char *syscall_name, + const struct bpf_ksyscall_opts *opts) +{ + LIBBPF_OPTS(bpf_kprobe_opts, kprobe_opts); + char func_name[128]; + + if (!OPTS_VALID(opts, bpf_ksyscall_opts)) + return libbpf_err_ptr(-EINVAL); + + if (kernel_supports(prog->obj, FEAT_SYSCALL_WRAPPER)) { + /* arch_specific_syscall_pfx() should never return NULL here + * because it is guarded by kernel_supports(). However, since + * compiler does not know that we have an explicit conditional + * as well. + */ + snprintf(func_name, sizeof(func_name), "__%s_sys_%s", + arch_specific_syscall_pfx() ? : "", syscall_name); + } else { + snprintf(func_name, sizeof(func_name), "__se_sys_%s", syscall_name); + } + + kprobe_opts.retprobe = OPTS_GET(opts, retprobe, false); + kprobe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0); + + return bpf_program__attach_kprobe_opts(prog, func_name, &kprobe_opts); +} + +/* Adapted from perf/util/string.c */ +static bool glob_match(const char *str, const char *pat) +{ + while (*str && *pat && *pat != '*') { + if (*pat == '?') { /* Matches any single character */ + str++; + pat++; + continue; + } + if (*str != *pat) + return false; + str++; + pat++; + } + /* Check wild card */ + if (*pat == '*') { + while (*pat == '*') + pat++; + if (!*pat) /* Tail wild card matches all */ + return true; + while (*str) + if (glob_match(str++, pat)) + return true; + } + return !*str && !*pat; +} + +struct kprobe_multi_resolve { + const char *pattern; + unsigned long *addrs; + size_t cap; + size_t cnt; +}; + +static int +resolve_kprobe_multi_cb(unsigned long long sym_addr, char sym_type, + const char *sym_name, void *ctx) +{ + struct kprobe_multi_resolve *res = ctx; + int err; + + if (!glob_match(sym_name, res->pattern)) + return 0; + + err = libbpf_ensure_mem((void **) &res->addrs, &res->cap, sizeof(unsigned long), + res->cnt + 1); + if (err) + return err; + + res->addrs[res->cnt++] = (unsigned long) sym_addr; + return 0; +} + +struct bpf_link * +bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog, + const char *pattern, + const struct bpf_kprobe_multi_opts *opts) +{ + LIBBPF_OPTS(bpf_link_create_opts, lopts); + struct kprobe_multi_resolve res = { + .pattern = pattern, + }; + struct bpf_link *link = NULL; + char errmsg[STRERR_BUFSIZE]; + const unsigned long *addrs; + int err, link_fd, prog_fd; + const __u64 *cookies; + const char **syms; + bool retprobe; + size_t cnt; + + if (!OPTS_VALID(opts, bpf_kprobe_multi_opts)) + return libbpf_err_ptr(-EINVAL); + + syms = OPTS_GET(opts, syms, false); + addrs = OPTS_GET(opts, addrs, false); + cnt = OPTS_GET(opts, cnt, false); + cookies = OPTS_GET(opts, cookies, false); + + if (!pattern && !addrs && !syms) + return libbpf_err_ptr(-EINVAL); + if (pattern && (addrs || syms || cookies || cnt)) + return libbpf_err_ptr(-EINVAL); + if (!pattern && !cnt) + return libbpf_err_ptr(-EINVAL); + if (addrs && syms) + return libbpf_err_ptr(-EINVAL); + + if (pattern) { + err = libbpf_kallsyms_parse(resolve_kprobe_multi_cb, &res); + if (err) + goto error; + if (!res.cnt) { + err = -ENOENT; + goto error; + } + addrs = res.addrs; + cnt = res.cnt; + } + + retprobe = OPTS_GET(opts, retprobe, false); + + lopts.kprobe_multi.syms = syms; + lopts.kprobe_multi.addrs = addrs; + lopts.kprobe_multi.cookies = cookies; + lopts.kprobe_multi.cnt = cnt; + lopts.kprobe_multi.flags = retprobe ? BPF_F_KPROBE_MULTI_RETURN : 0; + + link = calloc(1, sizeof(*link)); + if (!link) { + err = -ENOMEM; + goto error; + } + link->detach = &bpf_link__detach_fd; + + prog_fd = bpf_program__fd(prog); + link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_KPROBE_MULTI, &lopts); + if (link_fd < 0) { + err = -errno; + pr_warn("prog '%s': failed to attach: %s\n", + prog->name, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + goto error; + } + link->fd = link_fd; + free(res.addrs); + return link; + +error: + free(link); + free(res.addrs); + return libbpf_err_ptr(err); +} + +static int attach_kprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link) +{ + DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts); + unsigned long offset = 0; + const char *func_name; + char *func; + int n; + + *link = NULL; + + /* no auto-attach for SEC("kprobe") and SEC("kretprobe") */ + if (strcmp(prog->sec_name, "kprobe") == 0 || strcmp(prog->sec_name, "kretprobe") == 0) + return 0; + + opts.retprobe = str_has_pfx(prog->sec_name, "kretprobe/"); + if (opts.retprobe) + func_name = prog->sec_name + sizeof("kretprobe/") - 1; + else + func_name = prog->sec_name + sizeof("kprobe/") - 1; + + n = sscanf(func_name, "%m[a-zA-Z0-9_.]+%li", &func, &offset); + if (n < 1) { + pr_warn("kprobe name is invalid: %s\n", func_name); + return -EINVAL; + } + if (opts.retprobe && offset != 0) { + free(func); + pr_warn("kretprobes do not support offset specification\n"); + return -EINVAL; + } + + opts.offset = offset; + *link = bpf_program__attach_kprobe_opts(prog, func, &opts); + free(func); + return libbpf_get_error(*link); +} + +static int attach_ksyscall(const struct bpf_program *prog, long cookie, struct bpf_link **link) +{ + LIBBPF_OPTS(bpf_ksyscall_opts, opts); + const char *syscall_name; + + *link = NULL; + + /* no auto-attach for SEC("ksyscall") and SEC("kretsyscall") */ + if (strcmp(prog->sec_name, "ksyscall") == 0 || strcmp(prog->sec_name, "kretsyscall") == 0) + return 0; + + opts.retprobe = str_has_pfx(prog->sec_name, "kretsyscall/"); + if (opts.retprobe) + syscall_name = prog->sec_name + sizeof("kretsyscall/") - 1; + else + syscall_name = prog->sec_name + sizeof("ksyscall/") - 1; + + *link = bpf_program__attach_ksyscall(prog, syscall_name, &opts); + return *link ? 0 : -errno; +} + +static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link) +{ + LIBBPF_OPTS(bpf_kprobe_multi_opts, opts); + const char *spec; + char *pattern; + int n; + + *link = NULL; + + /* no auto-attach for SEC("kprobe.multi") and SEC("kretprobe.multi") */ + if (strcmp(prog->sec_name, "kprobe.multi") == 0 || + strcmp(prog->sec_name, "kretprobe.multi") == 0) + return 0; + + opts.retprobe = str_has_pfx(prog->sec_name, "kretprobe.multi/"); + if (opts.retprobe) + spec = prog->sec_name + sizeof("kretprobe.multi/") - 1; + else + spec = prog->sec_name + sizeof("kprobe.multi/") - 1; + + n = sscanf(spec, "%m[a-zA-Z0-9_.*?]", &pattern); + if (n < 1) { + pr_warn("kprobe multi pattern is invalid: %s\n", pattern); + return -EINVAL; + } + + *link = bpf_program__attach_kprobe_multi_opts(prog, pattern, &opts); + free(pattern); + return libbpf_get_error(*link); +} + +static void gen_uprobe_legacy_event_name(char *buf, size_t buf_sz, + const char *binary_path, uint64_t offset) +{ + int i; + + snprintf(buf, buf_sz, "libbpf_%u_%s_0x%zx", getpid(), binary_path, (size_t)offset); + + /* sanitize binary_path in the probe name */ + for (i = 0; buf[i]; i++) { + if (!isalnum(buf[i])) + buf[i] = '_'; + } +} + +static inline int add_uprobe_event_legacy(const char *probe_name, bool retprobe, + const char *binary_path, size_t offset) +{ + return append_to_file(tracefs_uprobe_events(), "%c:%s/%s %s:0x%zx", + retprobe ? 'r' : 'p', + retprobe ? "uretprobes" : "uprobes", + probe_name, binary_path, offset); +} + +static inline int remove_uprobe_event_legacy(const char *probe_name, bool retprobe) +{ + return append_to_file(tracefs_uprobe_events(), "-:%s/%s", + retprobe ? "uretprobes" : "uprobes", probe_name); +} + +static int determine_uprobe_perf_type_legacy(const char *probe_name, bool retprobe) +{ + char file[512]; + + snprintf(file, sizeof(file), "%s/events/%s/%s/id", + tracefs_path(), retprobe ? "uretprobes" : "uprobes", probe_name); + + return parse_uint_from_file(file, "%d\n"); +} + +static int perf_event_uprobe_open_legacy(const char *probe_name, bool retprobe, + const char *binary_path, size_t offset, int pid) +{ + const size_t attr_sz = sizeof(struct perf_event_attr); + struct perf_event_attr attr; + int type, pfd, err; + + err = add_uprobe_event_legacy(probe_name, retprobe, binary_path, offset); + if (err < 0) { + pr_warn("failed to add legacy uprobe event for %s:0x%zx: %d\n", + binary_path, (size_t)offset, err); + return err; + } + type = determine_uprobe_perf_type_legacy(probe_name, retprobe); + if (type < 0) { + err = type; + pr_warn("failed to determine legacy uprobe event id for %s:0x%zx: %d\n", + binary_path, offset, err); + goto err_clean_legacy; + } + + memset(&attr, 0, attr_sz); + attr.size = attr_sz; + attr.config = type; + attr.type = PERF_TYPE_TRACEPOINT; + + 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("legacy uprobe perf_event_open() failed: %d\n", err); + goto err_clean_legacy; + } + return pfd; + +err_clean_legacy: + /* Clear the newly added legacy uprobe_event */ + remove_uprobe_event_legacy(probe_name, retprobe); + return err; +} + +/* Return next ELF section of sh_type after scn, or first of that type if scn is NULL. */ +static Elf_Scn *elf_find_next_scn_by_type(Elf *elf, int sh_type, Elf_Scn *scn) +{ + while ((scn = elf_nextscn(elf, scn)) != NULL) { + GElf_Shdr sh; + + if (!gelf_getshdr(scn, &sh)) + continue; + if (sh.sh_type == sh_type) + return scn; + } + return NULL; +} + +/* Find offset of function name in object specified by path. "name" matches + * symbol name or name@@LIB for library functions. + */ +static long elf_find_func_offset(const char *binary_path, const char *name) +{ + int fd, i, sh_types[2] = { SHT_DYNSYM, SHT_SYMTAB }; + bool is_shared_lib, is_name_qualified; + char errmsg[STRERR_BUFSIZE]; + long ret = -ENOENT; + size_t name_len; + GElf_Ehdr ehdr; + Elf *elf; + + fd = open(binary_path, O_RDONLY | O_CLOEXEC); + if (fd < 0) { + ret = -errno; + pr_warn("failed to open %s: %s\n", binary_path, + libbpf_strerror_r(ret, errmsg, sizeof(errmsg))); + return ret; + } + elf = elf_begin(fd, ELF_C_READ_MMAP, NULL); + if (!elf) { + pr_warn("elf: could not read elf from %s: %s\n", binary_path, elf_errmsg(-1)); + close(fd); + return -LIBBPF_ERRNO__FORMAT; + } + if (!gelf_getehdr(elf, &ehdr)) { + pr_warn("elf: failed to get ehdr from %s: %s\n", binary_path, elf_errmsg(-1)); + ret = -LIBBPF_ERRNO__FORMAT; + goto out; + } + /* for shared lib case, we do not need to calculate relative offset */ + is_shared_lib = ehdr.e_type == ET_DYN; + + name_len = strlen(name); + /* Does name specify "@@LIB"? */ + is_name_qualified = strstr(name, "@@") != NULL; + + /* Search SHT_DYNSYM, SHT_SYMTAB for symbol. This search order is used because if + * a binary is stripped, it may only have SHT_DYNSYM, and a fully-statically + * linked binary may not have SHT_DYMSYM, so absence of a section should not be + * reported as a warning/error. + */ + for (i = 0; i < ARRAY_SIZE(sh_types); i++) { + size_t nr_syms, strtabidx, idx; + Elf_Data *symbols = NULL; + Elf_Scn *scn = NULL; + int last_bind = -1; + const char *sname; + GElf_Shdr sh; + + scn = elf_find_next_scn_by_type(elf, sh_types[i], NULL); + if (!scn) { + pr_debug("elf: failed to find symbol table ELF sections in '%s'\n", + binary_path); + continue; + } + if (!gelf_getshdr(scn, &sh)) + continue; + strtabidx = sh.sh_link; + symbols = elf_getdata(scn, 0); + if (!symbols) { + pr_warn("elf: failed to get symbols for symtab section in '%s': %s\n", + binary_path, elf_errmsg(-1)); + ret = -LIBBPF_ERRNO__FORMAT; + goto out; + } + nr_syms = symbols->d_size / sh.sh_entsize; + + for (idx = 0; idx < nr_syms; idx++) { + int curr_bind; + GElf_Sym sym; + Elf_Scn *sym_scn; + GElf_Shdr sym_sh; + + if (!gelf_getsym(symbols, idx, &sym)) + continue; + + if (GELF_ST_TYPE(sym.st_info) != STT_FUNC) + continue; + + sname = elf_strptr(elf, strtabidx, sym.st_name); + if (!sname) + continue; + + curr_bind = GELF_ST_BIND(sym.st_info); + + /* User can specify func, func@@LIB or func@@LIB_VERSION. */ + if (strncmp(sname, name, name_len) != 0) + continue; + /* ...but we don't want a search for "foo" to match 'foo2" also, so any + * additional characters in sname should be of the form "@@LIB". + */ + if (!is_name_qualified && sname[name_len] != '\0' && sname[name_len] != '@') + continue; + + if (ret >= 0) { + /* handle multiple matches */ + if (last_bind != STB_WEAK && curr_bind != STB_WEAK) { + /* Only accept one non-weak bind. */ + pr_warn("elf: ambiguous match for '%s', '%s' in '%s'\n", + sname, name, binary_path); + ret = -LIBBPF_ERRNO__FORMAT; + goto out; + } else if (curr_bind == STB_WEAK) { + /* already have a non-weak bind, and + * this is a weak bind, so ignore. + */ + continue; + } + } + + /* Transform symbol's virtual address (absolute for + * binaries and relative for shared libs) into file + * offset, which is what kernel is expecting for + * uprobe/uretprobe attachment. + * See Documentation/trace/uprobetracer.rst for more + * details. + * This is done by looking up symbol's containing + * section's header and using it's virtual address + * (sh_addr) and corresponding file offset (sh_offset) + * to transform sym.st_value (virtual address) into + * desired final file offset. + */ + sym_scn = elf_getscn(elf, sym.st_shndx); + if (!sym_scn) + continue; + if (!gelf_getshdr(sym_scn, &sym_sh)) + continue; + + ret = sym.st_value - sym_sh.sh_addr + sym_sh.sh_offset; + last_bind = curr_bind; + } + if (ret > 0) + break; + } + + if (ret > 0) { + pr_debug("elf: symbol address match for '%s' in '%s': 0x%lx\n", name, binary_path, + ret); + } else { + if (ret == 0) { + pr_warn("elf: '%s' is 0 in symtab for '%s': %s\n", name, binary_path, + is_shared_lib ? "should not be 0 in a shared library" : + "try using shared library path instead"); + ret = -ENOENT; + } else { + pr_warn("elf: failed to find symbol '%s' in '%s'\n", name, binary_path); + } + } +out: + elf_end(elf); + close(fd); + return ret; +} + +static const char *arch_specific_lib_paths(void) +{ + /* + * Based on https://packages.debian.org/sid/libc6. + * + * Assume that the traced program is built for the same architecture + * as libbpf, which should cover the vast majority of cases. + */ +#if defined(__x86_64__) + return "/lib/x86_64-linux-gnu"; +#elif defined(__i386__) + return "/lib/i386-linux-gnu"; +#elif defined(__s390x__) + return "/lib/s390x-linux-gnu"; +#elif defined(__s390__) + return "/lib/s390-linux-gnu"; +#elif defined(__arm__) && defined(__SOFTFP__) + return "/lib/arm-linux-gnueabi"; +#elif defined(__arm__) && !defined(__SOFTFP__) + return "/lib/arm-linux-gnueabihf"; +#elif defined(__aarch64__) + return "/lib/aarch64-linux-gnu"; +#elif defined(__mips__) && defined(__MIPSEL__) && _MIPS_SZLONG == 64 + return "/lib/mips64el-linux-gnuabi64"; +#elif defined(__mips__) && defined(__MIPSEL__) && _MIPS_SZLONG == 32 + return "/lib/mipsel-linux-gnu"; +#elif defined(__powerpc64__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + return "/lib/powerpc64le-linux-gnu"; +#elif defined(__sparc__) && defined(__arch64__) + return "/lib/sparc64-linux-gnu"; +#elif defined(__riscv) && __riscv_xlen == 64 + return "/lib/riscv64-linux-gnu"; +#else + return NULL; +#endif +} + +/* Get full path to program/shared library. */ +static int resolve_full_path(const char *file, char *result, size_t result_sz) +{ + const char *search_paths[3] = {}; + int i, perm; + + if (str_has_sfx(file, ".so") || strstr(file, ".so.")) { + search_paths[0] = getenv("LD_LIBRARY_PATH"); + search_paths[1] = "/usr/lib64:/usr/lib"; + search_paths[2] = arch_specific_lib_paths(); + perm = R_OK; + } else { + search_paths[0] = getenv("PATH"); + search_paths[1] = "/usr/bin:/usr/sbin"; + perm = R_OK | X_OK; + } + + for (i = 0; i < ARRAY_SIZE(search_paths); i++) { + const char *s; + + if (!search_paths[i]) + continue; + for (s = search_paths[i]; s != NULL; s = strchr(s, ':')) { + char *next_path; + int seg_len; + + if (s[0] == ':') + s++; + next_path = strchr(s, ':'); + seg_len = next_path ? next_path - s : strlen(s); + if (!seg_len) + continue; + snprintf(result, result_sz, "%.*s/%s", seg_len, s, file); + /* ensure it has required permissions */ + if (faccessat(AT_FDCWD, result, perm, AT_EACCESS) < 0) + continue; + pr_debug("resolved '%s' to '%s'\n", file, result); + return 0; + } + } + return -ENOENT; +} + +LIBBPF_API struct bpf_link * +bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid, + const char *binary_path, size_t func_offset, + const struct bpf_uprobe_opts *opts) +{ + DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts); + char errmsg[STRERR_BUFSIZE], *legacy_probe = NULL; + char full_binary_path[PATH_MAX]; + struct bpf_link *link; + size_t ref_ctr_off; + int pfd, err; + bool retprobe, legacy; + const char *func_name; + + if (!OPTS_VALID(opts, bpf_uprobe_opts)) + return libbpf_err_ptr(-EINVAL); + + retprobe = OPTS_GET(opts, retprobe, false); + ref_ctr_off = OPTS_GET(opts, ref_ctr_offset, 0); + pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0); + + if (!binary_path) + return libbpf_err_ptr(-EINVAL); + + if (!strchr(binary_path, '/')) { + err = resolve_full_path(binary_path, full_binary_path, + sizeof(full_binary_path)); + if (err) { + pr_warn("prog '%s': failed to resolve full path for '%s': %d\n", + prog->name, binary_path, err); + return libbpf_err_ptr(err); + } + binary_path = full_binary_path; + } + func_name = OPTS_GET(opts, func_name, NULL); + if (func_name) { + long sym_off; + + sym_off = elf_find_func_offset(binary_path, func_name); + if (sym_off < 0) + return libbpf_err_ptr(sym_off); + func_offset += sym_off; + } + + legacy = determine_uprobe_perf_type() < 0; + if (!legacy) { + pfd = perf_event_open_probe(true /* uprobe */, retprobe, binary_path, + func_offset, pid, ref_ctr_off); + } else { + char probe_name[PATH_MAX + 64]; + + if (ref_ctr_off) + return libbpf_err_ptr(-EINVAL); + + gen_uprobe_legacy_event_name(probe_name, sizeof(probe_name), + binary_path, func_offset); + + legacy_probe = strdup(probe_name); + if (!legacy_probe) + return libbpf_err_ptr(-ENOMEM); + + pfd = perf_event_uprobe_open_legacy(legacy_probe, retprobe, + binary_path, func_offset, pid); + } + if (pfd < 0) { + err = -errno; + 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(err, errmsg, sizeof(errmsg))); + goto err_out; + } + + link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts); + err = libbpf_get_error(link); + if (err) { + close(pfd); + 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))); + goto err_clean_legacy; + } + if (legacy) { + struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link); + + perf_link->legacy_probe_name = legacy_probe; + perf_link->legacy_is_kprobe = false; + perf_link->legacy_is_retprobe = retprobe; + } + return link; + +err_clean_legacy: + if (legacy) + remove_uprobe_event_legacy(legacy_probe, retprobe); +err_out: + free(legacy_probe); + return libbpf_err_ptr(err); +} + +/* Format of u[ret]probe section definition supporting auto-attach: + * u[ret]probe/binary:function[+offset] + * + * binary can be an absolute/relative path or a filename; the latter is resolved to a + * full binary path via bpf_program__attach_uprobe_opts. + * + * Specifying uprobe+ ensures we carry out strict matching; either "uprobe" must be + * specified (and auto-attach is not possible) or the above format is specified for + * auto-attach. + */ +static int attach_uprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link) +{ + DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, opts); + char *probe_type = NULL, *binary_path = NULL, *func_name = NULL; + int n, ret = -EINVAL; + long offset = 0; + + *link = NULL; + + n = sscanf(prog->sec_name, "%m[^/]/%m[^:]:%m[a-zA-Z0-9_.]+%li", + &probe_type, &binary_path, &func_name, &offset); + switch (n) { + case 1: + /* handle SEC("u[ret]probe") - format is valid, but auto-attach is impossible. */ + ret = 0; + break; + case 2: + pr_warn("prog '%s': section '%s' missing ':function[+offset]' specification\n", + prog->name, prog->sec_name); + break; + case 3: + case 4: + opts.retprobe = strcmp(probe_type, "uretprobe") == 0 || + strcmp(probe_type, "uretprobe.s") == 0; + if (opts.retprobe && offset != 0) { + pr_warn("prog '%s': uretprobes do not support offset specification\n", + prog->name); + break; + } + opts.func_name = func_name; + *link = bpf_program__attach_uprobe_opts(prog, -1, binary_path, offset, &opts); + ret = libbpf_get_error(*link); + break; + default: + pr_warn("prog '%s': invalid format of section definition '%s'\n", prog->name, + prog->sec_name); + break; + } + free(probe_type); + free(binary_path); + free(func_name); + + return ret; +} + +struct bpf_link *bpf_program__attach_uprobe(const struct bpf_program *prog, + bool retprobe, pid_t pid, + const char *binary_path, + size_t func_offset) +{ + DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, opts, .retprobe = retprobe); + + return bpf_program__attach_uprobe_opts(prog, pid, binary_path, func_offset, &opts); +} + +struct bpf_link *bpf_program__attach_usdt(const struct bpf_program *prog, + pid_t pid, const char *binary_path, + const char *usdt_provider, const char *usdt_name, + const struct bpf_usdt_opts *opts) +{ + char resolved_path[512]; + struct bpf_object *obj = prog->obj; + struct bpf_link *link; + __u64 usdt_cookie; + int err; + + if (!OPTS_VALID(opts, bpf_uprobe_opts)) + return libbpf_err_ptr(-EINVAL); + + if (bpf_program__fd(prog) < 0) { + pr_warn("prog '%s': can't attach BPF program w/o FD (did you load it?)\n", + prog->name); + return libbpf_err_ptr(-EINVAL); + } + + if (!binary_path) + return libbpf_err_ptr(-EINVAL); + + if (!strchr(binary_path, '/')) { + err = resolve_full_path(binary_path, resolved_path, sizeof(resolved_path)); + if (err) { + pr_warn("prog '%s': failed to resolve full path for '%s': %d\n", + prog->name, binary_path, err); + return libbpf_err_ptr(err); + } + binary_path = resolved_path; + } + + /* USDT manager is instantiated lazily on first USDT attach. It will + * be destroyed together with BPF object in bpf_object__close(). + */ + if (IS_ERR(obj->usdt_man)) + return libbpf_ptr(obj->usdt_man); + if (!obj->usdt_man) { + obj->usdt_man = usdt_manager_new(obj); + if (IS_ERR(obj->usdt_man)) + return libbpf_ptr(obj->usdt_man); + } + + usdt_cookie = OPTS_GET(opts, usdt_cookie, 0); + link = usdt_manager_attach_usdt(obj->usdt_man, prog, pid, binary_path, + usdt_provider, usdt_name, usdt_cookie); + err = libbpf_get_error(link); + if (err) + return libbpf_err_ptr(err); + return link; +} + +static int attach_usdt(const struct bpf_program *prog, long cookie, struct bpf_link **link) +{ + char *path = NULL, *provider = NULL, *name = NULL; + const char *sec_name; + int n, err; + + sec_name = bpf_program__section_name(prog); + if (strcmp(sec_name, "usdt") == 0) { + /* no auto-attach for just SEC("usdt") */ + *link = NULL; + return 0; + } + + n = sscanf(sec_name, "usdt/%m[^:]:%m[^:]:%m[^:]", &path, &provider, &name); + if (n != 3) { + pr_warn("invalid section '%s', expected SEC(\"usdt/<path>:<provider>:<name>\")\n", + sec_name); + err = -EINVAL; + } else { + *link = bpf_program__attach_usdt(prog, -1 /* any process */, path, + provider, name, NULL); + err = libbpf_get_error(*link); + } + free(path); + free(provider); + free(name); + return err; +} + +static int determine_tracepoint_id(const char *tp_category, + const char *tp_name) +{ + char file[PATH_MAX]; + int ret; + + ret = snprintf(file, sizeof(file), "%s/events/%s/%s/id", + tracefs_path(), 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) +{ + const size_t attr_sz = sizeof(struct perf_event_attr); + 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; + } + + memset(&attr, 0, attr_sz); + attr.type = PERF_TYPE_TRACEPOINT; + attr.size = attr_sz; + 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_opts(const struct bpf_program *prog, + const char *tp_category, + const char *tp_name, + const struct bpf_tracepoint_opts *opts) +{ + DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts); + char errmsg[STRERR_BUFSIZE]; + struct bpf_link *link; + int pfd, err; + + if (!OPTS_VALID(opts, bpf_tracepoint_opts)) + return libbpf_err_ptr(-EINVAL); + + pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0); + + 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 libbpf_err_ptr(pfd); + } + link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts); + err = libbpf_get_error(link); + if (err) { + close(pfd); + 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 libbpf_err_ptr(err); + } + return link; +} + +struct bpf_link *bpf_program__attach_tracepoint(const struct bpf_program *prog, + const char *tp_category, + const char *tp_name) +{ + return bpf_program__attach_tracepoint_opts(prog, tp_category, tp_name, NULL); +} + +static int attach_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link) +{ + char *sec_name, *tp_cat, *tp_name; + + *link = NULL; + + /* no auto-attach for SEC("tp") or SEC("tracepoint") */ + if (strcmp(prog->sec_name, "tp") == 0 || strcmp(prog->sec_name, "tracepoint") == 0) + return 0; + + sec_name = strdup(prog->sec_name); + if (!sec_name) + return -ENOMEM; + + /* extract "tp/<category>/<name>" or "tracepoint/<category>/<name>" */ + if (str_has_pfx(prog->sec_name, "tp/")) + tp_cat = sec_name + sizeof("tp/") - 1; + else + tp_cat = sec_name + sizeof("tracepoint/") - 1; + tp_name = strchr(tp_cat, '/'); + if (!tp_name) { + free(sec_name); + return -EINVAL; + } + *tp_name = '\0'; + tp_name++; + + *link = bpf_program__attach_tracepoint(prog, tp_cat, tp_name); + free(sec_name); + return libbpf_get_error(*link); +} + +struct bpf_link *bpf_program__attach_raw_tracepoint(const 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 libbpf_err_ptr(-EINVAL); + } + + link = calloc(1, sizeof(*link)); + if (!link) + return libbpf_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 libbpf_err_ptr(pfd); + } + link->fd = pfd; + return link; +} + +static int attach_raw_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link) +{ + static const char *const prefixes[] = { + "raw_tp", + "raw_tracepoint", + "raw_tp.w", + "raw_tracepoint.w", + }; + size_t i; + const char *tp_name = NULL; + + *link = NULL; + + for (i = 0; i < ARRAY_SIZE(prefixes); i++) { + size_t pfx_len; + + if (!str_has_pfx(prog->sec_name, prefixes[i])) + continue; + + pfx_len = strlen(prefixes[i]); + /* no auto-attach case of, e.g., SEC("raw_tp") */ + if (prog->sec_name[pfx_len] == '\0') + return 0; + + if (prog->sec_name[pfx_len] != '/') + continue; + + tp_name = prog->sec_name + pfx_len + 1; + break; + } + + if (!tp_name) { + pr_warn("prog '%s': invalid section name '%s'\n", + prog->name, prog->sec_name); + return -EINVAL; + } + + *link = bpf_program__attach_raw_tracepoint(prog, tp_name); + return libbpf_get_error(*link); +} + +/* Common logic for all BPF program types that attach to a btf_id */ +static struct bpf_link *bpf_program__attach_btf_id(const struct bpf_program *prog, + const struct bpf_trace_opts *opts) +{ + LIBBPF_OPTS(bpf_link_create_opts, link_opts); + char errmsg[STRERR_BUFSIZE]; + struct bpf_link *link; + int prog_fd, pfd; + + if (!OPTS_VALID(opts, bpf_trace_opts)) + return libbpf_err_ptr(-EINVAL); + + prog_fd = bpf_program__fd(prog); + if (prog_fd < 0) { + pr_warn("prog '%s': can't attach before loaded\n", prog->name); + return libbpf_err_ptr(-EINVAL); + } + + link = calloc(1, sizeof(*link)); + if (!link) + return libbpf_err_ptr(-ENOMEM); + link->detach = &bpf_link__detach_fd; + + /* libbpf is smart enough to redirect to BPF_RAW_TRACEPOINT_OPEN on old kernels */ + link_opts.tracing.cookie = OPTS_GET(opts, cookie, 0); + pfd = bpf_link_create(prog_fd, 0, bpf_program__expected_attach_type(prog), &link_opts); + 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 libbpf_err_ptr(pfd); + } + link->fd = pfd; + return link; +} + +struct bpf_link *bpf_program__attach_trace(const struct bpf_program *prog) +{ + return bpf_program__attach_btf_id(prog, NULL); +} + +struct bpf_link *bpf_program__attach_trace_opts(const struct bpf_program *prog, + const struct bpf_trace_opts *opts) +{ + return bpf_program__attach_btf_id(prog, opts); +} + +struct bpf_link *bpf_program__attach_lsm(const struct bpf_program *prog) +{ + return bpf_program__attach_btf_id(prog, NULL); +} + +static int attach_trace(const struct bpf_program *prog, long cookie, struct bpf_link **link) +{ + *link = bpf_program__attach_trace(prog); + return libbpf_get_error(*link); +} + +static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_link **link) +{ + *link = bpf_program__attach_lsm(prog); + return libbpf_get_error(*link); +} + +static struct bpf_link * +bpf_program__attach_fd(const 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 libbpf_err_ptr(-EINVAL); + } + + link = calloc(1, sizeof(*link)); + if (!link) + return libbpf_err_ptr(-ENOMEM); + link->detach = &bpf_link__detach_fd; + + attach_type = bpf_program__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 libbpf_err_ptr(link_fd); + } + link->fd = link_fd; + return link; +} + +struct bpf_link * +bpf_program__attach_cgroup(const struct bpf_program *prog, int cgroup_fd) +{ + return bpf_program__attach_fd(prog, cgroup_fd, 0, "cgroup"); +} + +struct bpf_link * +bpf_program__attach_netns(const struct bpf_program *prog, int netns_fd) +{ + return bpf_program__attach_fd(prog, netns_fd, 0, "netns"); +} + +struct bpf_link *bpf_program__attach_xdp(const 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(const 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 libbpf_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 libbpf_err_ptr(-EINVAL); + } + + if (target_fd) { + btf_id = libbpf_find_prog_btf_id(attach_func_name, target_fd); + if (btf_id < 0) + return libbpf_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(const 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 libbpf_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 libbpf_err_ptr(-EINVAL); + } + + link = calloc(1, sizeof(*link)); + if (!link) + return libbpf_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 libbpf_err_ptr(link_fd); + } + link->fd = link_fd; + return link; +} + +static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_link **link) +{ + *link = bpf_program__attach_iter(prog, NULL); + return libbpf_get_error(*link); +} + +struct bpf_link *bpf_program__attach(const struct bpf_program *prog) +{ + struct bpf_link *link = NULL; + int err; + + if (!prog->sec_def || !prog->sec_def->prog_attach_fn) + return libbpf_err_ptr(-EOPNOTSUPP); + + err = prog->sec_def->prog_attach_fn(prog, prog->sec_def->cookie, &link); + if (err) + return libbpf_err_ptr(err); + + /* When calling bpf_program__attach() explicitly, auto-attach support + * is expected to work, so NULL returned link is considered an error. + * This is different for skeleton's attach, see comment in + * bpf_object__attach_skeleton(). + */ + if (!link) + return libbpf_err_ptr(-EOPNOTSUPP); + + return link; +} + +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(const 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 libbpf_err_ptr(-EINVAL); + + link = calloc(1, sizeof(*link)); + if (!link) + return libbpf_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 libbpf_err_ptr(err); + } + + link->detach = bpf_link__detach_struct_ops; + link->fd = map->fd; + + return link; +} + +typedef enum bpf_perf_event_ret (*bpf_perf_event_print_t)(struct perf_event_header *hdr, + void *private_data); + +static enum bpf_perf_event_ret +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 libbpf_err(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, + perf_buffer_sample_fn sample_cb, + perf_buffer_lost_fn lost_cb, + void *ctx, + const struct perf_buffer_opts *opts) +{ + const size_t attr_sz = sizeof(struct perf_event_attr); + struct perf_buffer_params p = {}; + struct perf_event_attr attr; + + if (!OPTS_VALID(opts, perf_buffer_opts)) + return libbpf_err_ptr(-EINVAL); + + memset(&attr, 0, attr_sz); + attr.size = attr_sz; + 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 = sample_cb; + p.lost_cb = lost_cb; + p.ctx = ctx; + + return libbpf_ptr(__perf_buffer__new(map_fd, page_cnt, &p)); +} + +struct perf_buffer *perf_buffer__new_raw(int map_fd, size_t page_cnt, + struct perf_event_attr *attr, + perf_buffer_event_fn event_cb, void *ctx, + const struct perf_buffer_raw_opts *opts) +{ + struct perf_buffer_params p = {}; + + if (!attr) + return libbpf_err_ptr(-EINVAL); + + if (!OPTS_VALID(opts, perf_buffer_raw_opts)) + return libbpf_err_ptr(-EINVAL); + + p.attr = attr; + p.event_cb = event_cb; + p.ctx = ctx; + p.cpu_cnt = OPTS_GET(opts, cpu_cnt, 0); + p.cpus = OPTS_GET(opts, cpus, NULL); + p.map_keys = OPTS_GET(opts, map_keys, NULL); + + return libbpf_ptr(__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 == 0 || (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 = 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); + if (cnt < 0) + return -errno; + + 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 libbpf_err(err); + } + } + return 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 libbpf_err(-EINVAL); + + cpu_buf = pb->cpu_bufs[buf_idx]; + if (!cpu_buf) + return libbpf_err(-ENOENT); + + return cpu_buf->fd; +} + +int perf_buffer__buffer(struct perf_buffer *pb, int buf_idx, void **buf, size_t *buf_size) +{ + struct perf_cpu_buf *cpu_buf; + + if (buf_idx >= pb->cpu_cnt) + return libbpf_err(-EINVAL); + + cpu_buf = pb->cpu_bufs[buf_idx]; + if (!cpu_buf) + return libbpf_err(-ENOENT); + + *buf = cpu_buf->base; + *buf_size = pb->mmap_size; + return 0; +} + +/* + * 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 libbpf_err(-EINVAL); + + cpu_buf = pb->cpu_bufs[buf_idx]; + if (!cpu_buf) + return libbpf_err(-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 libbpf_err(err); + } + } + return 0; +} + +int bpf_program__set_attach_target(struct bpf_program *prog, + int attach_prog_fd, + const char *attach_func_name) +{ + int btf_obj_fd = 0, btf_id = 0, err; + + if (!prog || attach_prog_fd < 0) + return libbpf_err(-EINVAL); + + if (prog->obj->loaded) + return libbpf_err(-EINVAL); + + if (attach_prog_fd && !attach_func_name) { + /* remember attach_prog_fd and let bpf_program__load() find + * BTF ID during the program load + */ + prog->attach_prog_fd = attach_prog_fd; + return 0; + } + + if (attach_prog_fd) { + btf_id = libbpf_find_prog_btf_id(attach_func_name, + attach_prog_fd); + if (btf_id < 0) + return libbpf_err(btf_id); + } else { + if (!attach_func_name) + return libbpf_err(-EINVAL); + + /* load btf_vmlinux, if not yet */ + err = bpf_object__load_vmlinux_btf(prog->obj, true); + if (err) + return libbpf_err(err); + err = find_kernel_btf_id(prog->obj, attach_func_name, + prog->expected_attach_type, + &btf_obj_fd, &btf_id); + if (err) + return libbpf_err(err); + } + + prog->attach_btf_id = btf_id; + prog->attach_btf_obj_fd = btf_obj_fd; + 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 | O_CLOEXEC); + 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 libbpf_err(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; +} + +static int populate_skeleton_maps(const struct bpf_object *obj, + struct bpf_map_skeleton *maps, + size_t map_cnt) +{ + int i; + + for (i = 0; i < map_cnt; i++) { + struct bpf_map **map = maps[i].map; + const char *name = maps[i].name; + void **mmaped = 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; + } + return 0; +} + +static int populate_skeleton_progs(const struct bpf_object *obj, + struct bpf_prog_skeleton *progs, + size_t prog_cnt) +{ + int i; + + for (i = 0; i < prog_cnt; i++) { + struct bpf_program **prog = progs[i].prog; + const char *name = 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__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 err; + + /* 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); + err = libbpf_get_error(obj); + if (err) { + pr_warn("failed to initialize skeleton BPF object '%s': %d\n", + s->name, err); + return libbpf_err(err); + } + + *s->obj = obj; + err = populate_skeleton_maps(obj, s->maps, s->map_cnt); + if (err) { + pr_warn("failed to populate skeleton maps for '%s': %d\n", s->name, err); + return libbpf_err(err); + } + + err = populate_skeleton_progs(obj, s->progs, s->prog_cnt); + if (err) { + pr_warn("failed to populate skeleton progs for '%s': %d\n", s->name, err); + return libbpf_err(err); + } + + return 0; +} + +int bpf_object__open_subskeleton(struct bpf_object_subskeleton *s) +{ + int err, len, var_idx, i; + const char *var_name; + const struct bpf_map *map; + struct btf *btf; + __u32 map_type_id; + const struct btf_type *map_type, *var_type; + const struct bpf_var_skeleton *var_skel; + struct btf_var_secinfo *var; + + if (!s->obj) + return libbpf_err(-EINVAL); + + btf = bpf_object__btf(s->obj); + if (!btf) { + pr_warn("subskeletons require BTF at runtime (object %s)\n", + bpf_object__name(s->obj)); + return libbpf_err(-errno); + } + + err = populate_skeleton_maps(s->obj, s->maps, s->map_cnt); + if (err) { + pr_warn("failed to populate subskeleton maps: %d\n", err); + return libbpf_err(err); + } + + err = populate_skeleton_progs(s->obj, s->progs, s->prog_cnt); + if (err) { + pr_warn("failed to populate subskeleton maps: %d\n", err); + return libbpf_err(err); + } + + for (var_idx = 0; var_idx < s->var_cnt; var_idx++) { + var_skel = &s->vars[var_idx]; + map = *var_skel->map; + map_type_id = bpf_map__btf_value_type_id(map); + map_type = btf__type_by_id(btf, map_type_id); + + if (!btf_is_datasec(map_type)) { + pr_warn("type for map '%1$s' is not a datasec: %2$s", + bpf_map__name(map), + __btf_kind_str(btf_kind(map_type))); + return libbpf_err(-EINVAL); + } + + len = btf_vlen(map_type); + var = btf_var_secinfos(map_type); + for (i = 0; i < len; i++, var++) { + var_type = btf__type_by_id(btf, var->type); + var_name = btf__name_by_offset(btf, var_type->name_off); + if (strcmp(var_name, var_skel->name) == 0) { + *var_skel->addr = map->mmaped + var->offset; + break; + } + } + } + return 0; +} + +void bpf_object__destroy_subskeleton(struct bpf_object_subskeleton *s) +{ + if (!s) + return; + free(s->maps); + free(s->progs); + free(s->vars); + free(s); +} + +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 libbpf_err(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 libbpf_err(err); + } + } + + return 0; +} + +int bpf_object__attach_skeleton(struct bpf_object_skeleton *s) +{ + int i, err; + + for (i = 0; i < s->prog_cnt; i++) { + struct bpf_program *prog = *s->progs[i].prog; + struct bpf_link **link = s->progs[i].link; + + if (!prog->autoload || !prog->autoattach) + continue; + + /* auto-attaching not supported for this program */ + if (!prog->sec_def || !prog->sec_def->prog_attach_fn) + continue; + + /* if user already set the link manually, don't attempt auto-attach */ + if (*link) + continue; + + err = prog->sec_def->prog_attach_fn(prog, prog->sec_def->cookie, link); + if (err) { + pr_warn("prog '%s': failed to auto-attach: %d\n", + bpf_program__name(prog), err); + return libbpf_err(err); + } + + /* It's possible that for some SEC() definitions auto-attach + * is supported in some cases (e.g., if definition completely + * specifies target information), but is not in other cases. + * SEC("uprobe") is one such case. If user specified target + * binary and function name, such BPF program can be + * auto-attached. But if not, it shouldn't trigger skeleton's + * attach to fail. It should just be skipped. + * attach_fn signals such case with returning 0 (no error) and + * setting link to NULL. + */ + } + + 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); +} |