blob: f7fd3944d46d3e8e87eab66c239eed06e5bea81a [file] [log] [blame]
/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
* Internal libbpf helpers.
* Copyright (c) 2019 Facebook
#include <stdlib.h>
#include <limits.h>
#include <errno.h>
#include <linux/err.h>
#include "libbpf_legacy.h"
#include "relo_core.h"
/* make sure libbpf doesn't use kernel-only integer typedefs */
#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
/* prevent accidental re-addition of reallocarray() */
#pragma GCC poison reallocarray
#include "libbpf.h"
#include "btf.h"
#ifndef EM_BPF
#define EM_BPF 247
#ifndef R_BPF_64_64
#define R_BPF_64_64 1
#ifndef R_BPF_64_ABS64
#define R_BPF_64_ABS64 2
#ifndef R_BPF_64_ABS32
#define R_BPF_64_ABS32 3
#ifndef R_BPF_64_32
#define R_BPF_64_32 10
/* if libelf is old and doesn't support mmap(), fall back to read() */
/* Older libelf all end up in this expression, for both 32 and 64 bit */
#define GELF_ST_VISIBILITY(o) ((o) & 0x03)
#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_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) \
#define BTF_TYPE_TAG_ENC(value, type, component_idx) \
BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TAG, 0, 0), type), (component_idx)
#ifndef likely
#define likely(x) __builtin_expect(!!(x), 1)
#ifndef unlikely
#define unlikely(x) __builtin_expect(!!(x), 0)
#ifndef min
# define min(x, y) ((x) < (y) ? (x) : (y))
#ifndef max
# define max(x, y) ((x) < (y) ? (y) : (x))
#ifndef offsetofend
# define offsetofend(TYPE, FIELD) \
(offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD))
/* 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)
/* 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 \
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
* Re-implement glibc's reallocarray() for libbpf internal-only use.
* reallocarray(), unfortunately, is not available in all versions of glibc,
* so requires extra feature detection and using reallocarray() stub from
* <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates
* build of libbpf unnecessarily and is just a maintenance burden. Instead,
* it's trivial to implement libbpf-specific internal version and use it
* throughout libbpf.
static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size)
size_t total;
#if __has_builtin(__builtin_mul_overflow)
if (unlikely(__builtin_mul_overflow(nmemb, size, &total)))
return NULL;
if (size == 0 || nmemb > ULONG_MAX / size)
return NULL;
total = nmemb * size;
return realloc(ptr, total);
struct btf;
struct btf_type;
struct btf_type *btf_type_by_id(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_ALL = 0x3ff, /* 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;
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;
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); \
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);
struct bpf_prog_load_params {
enum bpf_prog_type prog_type;
enum bpf_attach_type expected_attach_type;
const char *name;
const struct bpf_insn *insns;
size_t insn_cnt;
const char *license;
__u32 kern_version;
__u32 attach_prog_fd;
__u32 attach_btf_obj_fd;
__u32 attach_btf_id;
__u32 prog_ifindex;
__u32 prog_btf_fd;
__u32 prog_flags;
__u32 func_info_rec_size;
const void *func_info;
__u32 func_info_cnt;
__u32 line_info_rec_size;
const void *line_info;
__u32 line_info_cnt;
__u32 log_level;
char *log_buf;
size_t log_buf_sz;
int *fd_array;
int libbpf__bpf_prog_load(const struct bpf_prog_load_params *load_attr);
int bpf_object__section_size(const struct bpf_object *obj, const char *name,
__u32 *size);
int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
__u32 *off);
struct btf *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;
#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);
extern enum libbpf_strict_mode libbpf_mode;
/* 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)
if (libbpf_mode & LIBBPF_STRICT_DIRECT_ERRS)
/* errno is already assumed to be set on error */
return ret < 0 ? -errno : ret;
/* legacy: on error return -1 directly and don't touch errno */
return 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;
if (libbpf_mode & LIBBPF_STRICT_CLEAN_PTRS)
return NULL;
/* legacy: encode err as ptr */
return ERR_PTR(err);
/* 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);
if (libbpf_mode & LIBBPF_STRICT_CLEAN_PTRS)
return IS_ERR(ret) ? NULL : ret;
/* legacy: pass-through original pointer */
return 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);