/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ /* * Internal libbpf helpers. * * Copyright (c) 2019 Facebook */ #ifndef __LIBBPF_LIBBPF_INTERNAL_H #define __LIBBPF_LIBBPF_INTERNAL_H #include #include #include #include #include #include #include #include #include "relo_core.h" /* Android's libc doesn't support AT_EACCESS in faccessat() implementation * ([0]), and just returns -EINVAL even if file exists and is accessible. * See [1] for issues caused by this. * * So just redefine it to 0 on Android. * * [0] https://android.googlesource.com/platform/bionic/+/refs/heads/android13-release/libc/bionic/faccessat.cpp#50 * [1] https://github.com/libbpf/libbpf-bootstrap/issues/250#issuecomment-1911324250 */ #ifdef __ANDROID__ #undef AT_EACCESS #define AT_EACCESS 0 #endif /* make sure libbpf doesn't use kernel-only integer typedefs */ #pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 /* prevent accidental re-addition of reallocarray() */ #pragma GCC poison reallocarray #include "libbpf.h" #include "btf.h" #ifndef EM_BPF #define EM_BPF 247 #endif #ifndef R_BPF_64_64 #define R_BPF_64_64 1 #endif #ifndef R_BPF_64_ABS64 #define R_BPF_64_ABS64 2 #endif #ifndef R_BPF_64_ABS32 #define R_BPF_64_ABS32 3 #endif #ifndef R_BPF_64_32 #define R_BPF_64_32 10 #endif #ifndef SHT_LLVM_ADDRSIG #define SHT_LLVM_ADDRSIG 0x6FFF4C03 #endif /* if libelf is old and doesn't support mmap(), fall back to read() */ #ifndef ELF_C_READ_MMAP #define ELF_C_READ_MMAP ELF_C_READ #endif /* Older libelf all end up in this expression, for both 32 and 64 bit */ #ifndef ELF64_ST_VISIBILITY #define ELF64_ST_VISIBILITY(o) ((o) & 0x03) #endif #define BTF_INFO_ENC(kind, kind_flag, vlen) \ ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN)) #define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type) #define BTF_INT_ENC(encoding, bits_offset, nr_bits) \ ((encoding) << 24 | (bits_offset) << 16 | (nr_bits)) #define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \ BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \ BTF_INT_ENC(encoding, bits_offset, bits) #define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset) #define BTF_PARAM_ENC(name, type) (name), (type) #define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size) #define BTF_TYPE_FLOAT_ENC(name, sz) \ BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz) #define BTF_TYPE_DECL_TAG_ENC(value, type, component_idx) \ BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_DECL_TAG, 0, 0), type), (component_idx) #define BTF_TYPE_TYPE_TAG_ENC(value, type) \ BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TYPE_TAG, 0, 0), type) #ifndef likely #define likely(x) __builtin_expect(!!(x), 1) #endif #ifndef unlikely #define unlikely(x) __builtin_expect(!!(x), 0) #endif #ifndef min # define min(x, y) ((x) < (y) ? (x) : (y)) #endif #ifndef max # define max(x, y) ((x) < (y) ? (y) : (x)) #endif #ifndef offsetofend # define offsetofend(TYPE, FIELD) \ (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD)) #endif #ifndef __alias #define __alias(symbol) __attribute__((alias(#symbol))) #endif /* Check whether a string `str` has prefix `pfx`, regardless if `pfx` is * a string literal known at compilation time or char * pointer known only at * runtime. */ #define str_has_pfx(str, pfx) \ (strncmp(str, pfx, __builtin_constant_p(pfx) ? sizeof(pfx) - 1 : strlen(pfx)) == 0) /* suffix check */ static inline bool str_has_sfx(const char *str, const char *sfx) { size_t str_len = strlen(str); size_t sfx_len = strlen(sfx); if (sfx_len > str_len) return false; return strcmp(str + str_len - sfx_len, sfx) == 0; } /* Symbol versioning is different between static and shared library. * Properly versioned symbols are needed for shared library, but * only the symbol of the new version is needed for static library. * Starting with GNU C 10, use symver attribute instead of .symver assembler * directive, which works better with GCC LTO builds. */ #if defined(SHARED) && defined(__GNUC__) && __GNUC__ >= 10 #define DEFAULT_VERSION(internal_name, api_name, version) \ __attribute__((symver(#api_name "@@" #version))) #define COMPAT_VERSION(internal_name, api_name, version) \ __attribute__((symver(#api_name "@" #version))) #elif defined(SHARED) #define COMPAT_VERSION(internal_name, api_name, version) \ asm(".symver " #internal_name "," #api_name "@" #version); #define DEFAULT_VERSION(internal_name, api_name, version) \ asm(".symver " #internal_name "," #api_name "@@" #version); #else /* !SHARED */ #define COMPAT_VERSION(internal_name, api_name, version) #define DEFAULT_VERSION(internal_name, api_name, version) \ extern typeof(internal_name) api_name \ __attribute__((alias(#internal_name))); #endif extern void libbpf_print(enum libbpf_print_level level, const char *format, ...) __attribute__((format(printf, 2, 3))); #define __pr(level, fmt, ...) \ do { \ libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \ } while (0) #define pr_warn(fmt, ...) __pr(LIBBPF_WARN, fmt, ##__VA_ARGS__) #define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__) #define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__) #ifndef __has_builtin #define __has_builtin(x) 0 #endif struct bpf_link { int (*detach)(struct bpf_link *link); void (*dealloc)(struct bpf_link *link); char *pin_path; /* NULL, if not pinned */ int fd; /* hook FD, -1 if not applicable */ bool disconnected; }; /* * Re-implement glibc's reallocarray() for libbpf internal-only use. * reallocarray(), unfortunately, is not available in all versions of glibc, * so requires extra feature detection and using reallocarray() stub from * and COMPAT_NEED_REALLOCARRAY. All this complicates * build of libbpf unnecessarily and is just a maintenance burden. Instead, * it's trivial to implement libbpf-specific internal version and use it * throughout libbpf. */ static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size) { size_t total; #if __has_builtin(__builtin_mul_overflow) if (unlikely(__builtin_mul_overflow(nmemb, size, &total))) return NULL; #else if (size == 0 || nmemb > ULONG_MAX / size) return NULL; total = nmemb * size; #endif return realloc(ptr, total); } /* Copy up to sz - 1 bytes from zero-terminated src string and ensure that dst * is zero-terminated string no matter what (unless sz == 0, in which case * it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but differs * in what is returned. Given this is internal helper, it's trivial to extend * this, when necessary. Use this instead of strncpy inside libbpf source code. */ static inline void libbpf_strlcpy(char *dst, const char *src, size_t sz) { size_t i; if (sz == 0) return; sz--; for (i = 0; i < sz && src[i]; i++) dst[i] = src[i]; dst[i] = '\0'; } __u32 get_kernel_version(void); struct btf; struct btf_type; struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id); const char *btf_kind_str(const struct btf_type *t); const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id); static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t) { return (enum btf_func_linkage)(int)btf_vlen(t); } static inline __u32 btf_type_info(int kind, int vlen, int kflag) { return (kflag << 31) | (kind << 24) | vlen; } enum map_def_parts { MAP_DEF_MAP_TYPE = 0x001, MAP_DEF_KEY_TYPE = 0x002, MAP_DEF_KEY_SIZE = 0x004, MAP_DEF_VALUE_TYPE = 0x008, MAP_DEF_VALUE_SIZE = 0x010, MAP_DEF_MAX_ENTRIES = 0x020, MAP_DEF_MAP_FLAGS = 0x040, MAP_DEF_NUMA_NODE = 0x080, MAP_DEF_PINNING = 0x100, MAP_DEF_INNER_MAP = 0x200, MAP_DEF_MAP_EXTRA = 0x400, MAP_DEF_ALL = 0x7ff, /* combination of all above */ }; struct btf_map_def { enum map_def_parts parts; __u32 map_type; __u32 key_type_id; __u32 key_size; __u32 value_type_id; __u32 value_size; __u32 max_entries; __u32 map_flags; __u32 numa_node; __u32 pinning; __u64 map_extra; }; 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); void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t cur_cnt, size_t max_cnt, size_t add_cnt); int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt); static inline bool libbpf_is_mem_zeroed(const char *p, ssize_t len) { while (len > 0) { if (*p) return false; p++; len--; } return true; } static inline bool libbpf_validate_opts(const char *opts, size_t opts_sz, size_t user_sz, const char *type_name) { if (user_sz < sizeof(size_t)) { pr_warn("%s size (%zu) is too small\n", type_name, user_sz); return false; } if (!libbpf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) { pr_warn("%s has non-zero extra bytes\n", type_name); return false; } return true; } #define OPTS_VALID(opts, type) \ (!(opts) || libbpf_validate_opts((const char *)opts, \ offsetofend(struct type, \ type##__last_field), \ (opts)->sz, #type)) #define OPTS_HAS(opts, field) \ ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field)) #define OPTS_GET(opts, field, fallback_value) \ (OPTS_HAS(opts, field) ? (opts)->field : fallback_value) #define OPTS_SET(opts, field, value) \ do { \ if (OPTS_HAS(opts, field)) \ (opts)->field = value; \ } while (0) #define OPTS_ZEROED(opts, last_nonzero_field) \ ({ \ ssize_t __off = offsetofend(typeof(*(opts)), last_nonzero_field); \ !(opts) || libbpf_is_mem_zeroed((const void *)opts + __off, \ (opts)->sz - __off); \ }) enum kern_feature_id { /* v4.14: kernel support for program & map names. */ FEAT_PROG_NAME, /* v5.2: kernel support for global data sections. */ FEAT_GLOBAL_DATA, /* BTF support */ FEAT_BTF, /* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */ FEAT_BTF_FUNC, /* BTF_KIND_VAR and BTF_KIND_DATASEC support */ FEAT_BTF_DATASEC, /* BTF_FUNC_GLOBAL is supported */ FEAT_BTF_GLOBAL_FUNC, /* BPF_F_MMAPABLE is supported for arrays */ FEAT_ARRAY_MMAP, /* kernel support for expected_attach_type in BPF_PROG_LOAD */ FEAT_EXP_ATTACH_TYPE, /* bpf_probe_read_{kernel,user}[_str] helpers */ FEAT_PROBE_READ_KERN, /* BPF_PROG_BIND_MAP is supported */ FEAT_PROG_BIND_MAP, /* Kernel support for module BTFs */ FEAT_MODULE_BTF, /* BTF_KIND_FLOAT support */ FEAT_BTF_FLOAT, /* BPF perf link support */ FEAT_PERF_LINK, /* BTF_KIND_DECL_TAG support */ FEAT_BTF_DECL_TAG, /* BTF_KIND_TYPE_TAG support */ FEAT_BTF_TYPE_TAG, /* memcg-based accounting for BPF maps and progs */ FEAT_MEMCG_ACCOUNT, /* BPF cookie (bpf_get_attach_cookie() BPF helper) support */ FEAT_BPF_COOKIE, /* BTF_KIND_ENUM64 support and BTF_KIND_ENUM kflag support */ FEAT_BTF_ENUM64, /* Kernel uses syscall wrapper (CONFIG_ARCH_HAS_SYSCALL_WRAPPER) */ FEAT_SYSCALL_WRAPPER, /* BPF multi-uprobe link support */ FEAT_UPROBE_MULTI_LINK, /* Kernel supports arg:ctx tag (__arg_ctx) for global subprogs natively */ FEAT_ARG_CTX_TAG, /* Kernel supports '?' at the front of datasec names */ FEAT_BTF_QMARK_DATASEC, __FEAT_CNT, }; enum kern_feature_result { FEAT_UNKNOWN = 0, FEAT_SUPPORTED = 1, FEAT_MISSING = 2, }; struct kern_feature_cache { enum kern_feature_result res[__FEAT_CNT]; int token_fd; }; bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id); bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id); int probe_kern_syscall_wrapper(int token_fd); int probe_memcg_account(int token_fd); int bump_rlimit_memlock(void); int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz); int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz); int libbpf__load_raw_btf(const char *raw_types, size_t types_len, const char *str_sec, size_t str_len, int token_fd); int btf_load_into_kernel(struct btf *btf, char *log_buf, size_t log_sz, __u32 log_level, int token_fd); struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf); void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type, const char **prefix, int *kind); struct btf_ext_info { /* * info points to the individual info section (e.g. func_info and * line_info) from the .BTF.ext. It does not include the __u32 rec_size. */ void *info; __u32 rec_size; __u32 len; /* optional (maintained internally by libbpf) mapping between .BTF.ext * section and corresponding ELF section. This is used to join * information like CO-RE relocation records with corresponding BPF * programs defined in ELF sections */ __u32 *sec_idxs; int sec_cnt; }; #define for_each_btf_ext_sec(seg, sec) \ for (sec = (seg)->info; \ (void *)sec < (seg)->info + (seg)->len; \ sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \ (seg)->rec_size * sec->num_info) #define for_each_btf_ext_rec(seg, sec, i, rec) \ for (i = 0, rec = (void *)&(sec)->data; \ i < (sec)->num_info; \ i++, rec = (void *)rec + (seg)->rec_size) /* * The .BTF.ext ELF section layout defined as * struct btf_ext_header * func_info subsection * * The func_info subsection layout: * record size for struct bpf_func_info in the func_info subsection * struct btf_sec_func_info for section #1 * a list of bpf_func_info records for section #1 * where struct bpf_func_info mimics one in include/uapi/linux/bpf.h * but may not be identical * struct btf_sec_func_info for section #2 * a list of bpf_func_info records for section #2 * ...... * * Note that the bpf_func_info record size in .BTF.ext may not * be the same as the one defined in include/uapi/linux/bpf.h. * The loader should ensure that record_size meets minimum * requirement and pass the record as is to the kernel. The * kernel will handle the func_info properly based on its contents. */ struct btf_ext_header { __u16 magic; __u8 version; __u8 flags; __u32 hdr_len; /* All offsets are in bytes relative to the end of this header */ __u32 func_info_off; __u32 func_info_len; __u32 line_info_off; __u32 line_info_len; /* optional part of .BTF.ext header */ __u32 core_relo_off; __u32 core_relo_len; }; struct btf_ext { union { struct btf_ext_header *hdr; void *data; }; struct btf_ext_info func_info; struct btf_ext_info line_info; struct btf_ext_info core_relo_info; __u32 data_size; }; struct btf_ext_info_sec { __u32 sec_name_off; __u32 num_info; /* Followed by num_info * record_size number of bytes */ __u8 data[]; }; /* The minimum bpf_func_info checked by the loader */ struct bpf_func_info_min { __u32 insn_off; __u32 type_id; }; /* The minimum bpf_line_info checked by the loader */ struct bpf_line_info_min { __u32 insn_off; __u32 file_name_off; __u32 line_off; __u32 line_col; }; typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx); typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx); int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ctx); int btf_type_visit_str_offs(struct btf_type *t, str_off_visit_fn visit, void *ctx); int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx); int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx); __s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name, __u32 kind); /* handle direct returned errors */ static inline int libbpf_err(int ret) { if (ret < 0) errno = -ret; return ret; } /* handle errno-based (e.g., syscall or libc) errors according to libbpf's * strict mode settings */ static inline int libbpf_err_errno(int ret) { /* errno is already assumed to be set on error */ return ret < 0 ? -errno : ret; } /* handle error for pointer-returning APIs, err is assumed to be < 0 always */ static inline void *libbpf_err_ptr(int err) { /* set errno on error, this doesn't break anything */ errno = -err; return NULL; } /* handle pointer-returning APIs' error handling */ static inline void *libbpf_ptr(void *ret) { /* set errno on error, this doesn't break anything */ if (IS_ERR(ret)) errno = -PTR_ERR(ret); return IS_ERR(ret) ? NULL : ret; } static inline bool str_is_empty(const char *s) { return !s || !s[0]; } static inline bool is_ldimm64_insn(struct bpf_insn *insn) { return insn->code == (BPF_LD | BPF_IMM | BPF_DW); } /* Unconditionally dup FD, ensuring it doesn't use [0, 2] range. * Original FD is not closed or altered in any other way. * Preserves original FD value, if it's invalid (negative). */ static inline int dup_good_fd(int fd) { if (fd < 0) return fd; return fcntl(fd, F_DUPFD_CLOEXEC, 3); } /* if fd is stdin, stdout, or stderr, dup to a fd greater than 2 * Takes ownership of the fd passed in, and closes it if calling * fcntl(fd, F_DUPFD_CLOEXEC, 3). */ static inline int ensure_good_fd(int fd) { int old_fd = fd, saved_errno; if (fd < 0) return fd; if (fd < 3) { fd = dup_good_fd(fd); saved_errno = errno; close(old_fd); errno = saved_errno; if (fd < 0) { pr_warn("failed to dup FD %d to FD > 2: %d\n", old_fd, -saved_errno); errno = saved_errno; } } return fd; } static inline int sys_dup3(int oldfd, int newfd, int flags) { return syscall(__NR_dup3, oldfd, newfd, flags); } /* Point *fixed_fd* to the same file that *tmp_fd* points to. * Regardless of success, *tmp_fd* is closed. * Whatever *fixed_fd* pointed to is closed silently. */ static inline int reuse_fd(int fixed_fd, int tmp_fd) { int err; err = sys_dup3(tmp_fd, fixed_fd, O_CLOEXEC); err = err < 0 ? -errno : 0; close(tmp_fd); /* clean up temporary FD */ return err; } /* The following two functions are exposed to bpftool */ 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); void bpf_core_free_cands(struct bpf_core_cand_list *cands); struct usdt_manager *usdt_manager_new(struct bpf_object *obj); void usdt_manager_free(struct usdt_manager *man); struct bpf_link * usdt_manager_attach_usdt(struct usdt_manager *man, const struct bpf_program *prog, pid_t pid, const char *path, const char *usdt_provider, const char *usdt_name, __u64 usdt_cookie); static inline bool is_pow_of_2(size_t x) { return x && (x & (x - 1)) == 0; } #define PROG_LOAD_ATTEMPTS 5 int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size, int attempts); bool glob_match(const char *str, const char *pat); long elf_find_func_offset(Elf *elf, const char *binary_path, const char *name); long elf_find_func_offset_from_file(const char *binary_path, const char *name); struct elf_fd { Elf *elf; int fd; }; int elf_open(const char *binary_path, struct elf_fd *elf_fd); void elf_close(struct elf_fd *elf_fd); int elf_resolve_syms_offsets(const char *binary_path, int cnt, const char **syms, unsigned long **poffsets, int st_type); int elf_resolve_pattern_offsets(const char *binary_path, const char *pattern, unsigned long **poffsets, size_t *pcnt); int probe_fd(int fd); #endif /* __LIBBPF_LIBBPF_INTERNAL_H */