/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
/*
* Internal libbpf helpers.
*
* Copyright (c) 2019 Facebook
*/
#ifndef __LIBBPF_LIBBPF_INTERNAL_H
#define __LIBBPF_LIBBPF_INTERNAL_H
#include <stdlib.h>
#include <limits.h>
#include <errno.h>
#include <linux/err.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <libelf.h>
#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
* <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates
* build of libbpf unnecessarily and is just a maintenance burden. Instead,
* it's trivial to implement libbpf-specific internal version and use it
* throughout libbpf.
*/
static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size)
{
size_t total;
#if __has_builtin(__builtin_mul_overflow)
if (unlikely(__builtin_mul_overflow(nmemb, size, &total)))
return NULL;
#else
if (size == 0 || nmemb > ULONG_MAX / size)
return NULL;
total = nmemb * size;
#endif
return realloc(ptr, total);
}
/* 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);
const struct btf_header *btf_header(const struct btf *btf);
void btf_set_base_btf(struct btf *btf, const struct btf *base_btf);
int btf_relocate(struct btf *btf, const struct btf *base_btf, __u32 **id_map);
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;
};
enum btf_field_iter_kind {
BTF_FIELD_ITER_IDS,
BTF_FIELD_ITER_STRS,
};
struct btf_field_desc {
/* once-per-type offsets */
int t_off_cnt, t_offs[2];
/* member struct size, or zero, if no members */
int m_sz;
/* repeated per-member offsets */
int m_off_cnt, m_offs[1];
};
struct btf_field_iter {
struct btf_field_desc desc;
void *p;
int m_idx;
int off_idx;
int vlen;
};
int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t, enum btf_field_iter_kind iter_kind);
__u32 *btf_field_iter_next(struct btf_field_iter *it);
typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx);
typedef int (*str_off_visit_fn)(__u32 *str_off, 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 */
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