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529 lines
15 KiB
529 lines
15 KiB
/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ |
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/* |
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* Internal libbpf helpers. |
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* |
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* Copyright (c) 2019 Facebook |
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*/ |
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#ifndef __LIBBPF_LIBBPF_INTERNAL_H |
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#define __LIBBPF_LIBBPF_INTERNAL_H |
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#include <stdlib.h> |
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#include <limits.h> |
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#include <errno.h> |
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#include <linux/err.h> |
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#include <fcntl.h> |
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#include <unistd.h> |
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#include "libbpf_legacy.h" |
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#include "relo_core.h" |
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/* make sure libbpf doesn't use kernel-only integer typedefs */ |
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#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 |
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/* prevent accidental re-addition of reallocarray() */ |
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#pragma GCC poison reallocarray |
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#include "libbpf.h" |
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#include "btf.h" |
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#ifndef EM_BPF |
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#define EM_BPF 247 |
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#endif |
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#ifndef R_BPF_64_64 |
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#define R_BPF_64_64 1 |
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#endif |
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#ifndef R_BPF_64_ABS64 |
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#define R_BPF_64_ABS64 2 |
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#endif |
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#ifndef R_BPF_64_ABS32 |
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#define R_BPF_64_ABS32 3 |
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#endif |
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#ifndef R_BPF_64_32 |
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#define R_BPF_64_32 10 |
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#endif |
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#ifndef SHT_LLVM_ADDRSIG |
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#define SHT_LLVM_ADDRSIG 0x6FFF4C03 |
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#endif |
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/* if libelf is old and doesn't support mmap(), fall back to read() */ |
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#ifndef ELF_C_READ_MMAP |
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#define ELF_C_READ_MMAP ELF_C_READ |
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#endif |
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/* Older libelf all end up in this expression, for both 32 and 64 bit */ |
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#ifndef ELF64_ST_VISIBILITY |
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#define ELF64_ST_VISIBILITY(o) ((o) & 0x03) |
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#endif |
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#define BTF_INFO_ENC(kind, kind_flag, vlen) \ |
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((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN)) |
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#define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type) |
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#define BTF_INT_ENC(encoding, bits_offset, nr_bits) \ |
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((encoding) << 24 | (bits_offset) << 16 | (nr_bits)) |
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#define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \ |
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BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \ |
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BTF_INT_ENC(encoding, bits_offset, bits) |
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#define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset) |
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#define BTF_PARAM_ENC(name, type) (name), (type) |
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#define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size) |
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#define BTF_TYPE_FLOAT_ENC(name, sz) \ |
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BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz) |
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#define BTF_TYPE_DECL_TAG_ENC(value, type, component_idx) \ |
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BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_DECL_TAG, 0, 0), type), (component_idx) |
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#define BTF_TYPE_TYPE_TAG_ENC(value, type) \ |
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BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TYPE_TAG, 0, 0), type) |
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#ifndef likely |
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#define likely(x) __builtin_expect(!!(x), 1) |
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#endif |
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#ifndef unlikely |
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#define unlikely(x) __builtin_expect(!!(x), 0) |
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#endif |
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#ifndef min |
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# define min(x, y) ((x) < (y) ? (x) : (y)) |
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#endif |
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#ifndef max |
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# define max(x, y) ((x) < (y) ? (y) : (x)) |
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#endif |
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#ifndef offsetofend |
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# define offsetofend(TYPE, FIELD) \ |
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(offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD)) |
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#endif |
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/* Check whether a string `str` has prefix `pfx`, regardless if `pfx` is |
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* a string literal known at compilation time or char * pointer known only at |
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* runtime. |
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*/ |
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#define str_has_pfx(str, pfx) \ |
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(strncmp(str, pfx, __builtin_constant_p(pfx) ? sizeof(pfx) - 1 : strlen(pfx)) == 0) |
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/* Symbol versioning is different between static and shared library. |
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* Properly versioned symbols are needed for shared library, but |
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* only the symbol of the new version is needed for static library. |
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* Starting with GNU C 10, use symver attribute instead of .symver assembler |
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* directive, which works better with GCC LTO builds. |
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*/ |
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#if defined(SHARED) && defined(__GNUC__) && __GNUC__ >= 10 |
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#define DEFAULT_VERSION(internal_name, api_name, version) \ |
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__attribute__((symver(#api_name "@@" #version))) |
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#define COMPAT_VERSION(internal_name, api_name, version) \ |
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__attribute__((symver(#api_name "@" #version))) |
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#elif defined(SHARED) |
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#define COMPAT_VERSION(internal_name, api_name, version) \ |
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asm(".symver " #internal_name "," #api_name "@" #version); |
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#define DEFAULT_VERSION(internal_name, api_name, version) \ |
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asm(".symver " #internal_name "," #api_name "@@" #version); |
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#else /* !SHARED */ |
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#define COMPAT_VERSION(internal_name, api_name, version) |
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#define DEFAULT_VERSION(internal_name, api_name, version) \ |
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extern typeof(internal_name) api_name \ |
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__attribute__((alias(#internal_name))); |
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#endif |
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extern void libbpf_print(enum libbpf_print_level level, |
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const char *format, ...) |
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__attribute__((format(printf, 2, 3))); |
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#define __pr(level, fmt, ...) \ |
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do { \ |
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libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \ |
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} while (0) |
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#define pr_warn(fmt, ...) __pr(LIBBPF_WARN, fmt, ##__VA_ARGS__) |
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#define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__) |
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#define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__) |
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#ifndef __has_builtin |
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#define __has_builtin(x) 0 |
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#endif |
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/* |
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* Re-implement glibc's reallocarray() for libbpf internal-only use. |
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* reallocarray(), unfortunately, is not available in all versions of glibc, |
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* so requires extra feature detection and using reallocarray() stub from |
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* <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates |
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* build of libbpf unnecessarily and is just a maintenance burden. Instead, |
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* it's trivial to implement libbpf-specific internal version and use it |
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* throughout libbpf. |
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*/ |
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static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size) |
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{ |
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size_t total; |
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#if __has_builtin(__builtin_mul_overflow) |
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if (unlikely(__builtin_mul_overflow(nmemb, size, &total))) |
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return NULL; |
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#else |
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if (size == 0 || nmemb > ULONG_MAX / size) |
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return NULL; |
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total = nmemb * size; |
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#endif |
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return realloc(ptr, total); |
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} |
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/* Copy up to sz - 1 bytes from zero-terminated src string and ensure that dst |
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* is zero-terminated string no matter what (unless sz == 0, in which case |
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* it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but differs |
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* in what is returned. Given this is internal helper, it's trivial to extend |
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* this, when necessary. Use this instead of strncpy inside libbpf source code. |
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*/ |
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static inline void libbpf_strlcpy(char *dst, const char *src, size_t sz) |
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{ |
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size_t i; |
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if (sz == 0) |
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return; |
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sz--; |
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for (i = 0; i < sz && src[i]; i++) |
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dst[i] = src[i]; |
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dst[i] = '\0'; |
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} |
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__u32 get_kernel_version(void); |
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struct btf; |
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struct btf_type; |
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struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id); |
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const char *btf_kind_str(const struct btf_type *t); |
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const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id); |
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static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t) |
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{ |
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return (enum btf_func_linkage)(int)btf_vlen(t); |
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} |
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static inline __u32 btf_type_info(int kind, int vlen, int kflag) |
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{ |
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return (kflag << 31) | (kind << 24) | vlen; |
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} |
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enum map_def_parts { |
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MAP_DEF_MAP_TYPE = 0x001, |
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MAP_DEF_KEY_TYPE = 0x002, |
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MAP_DEF_KEY_SIZE = 0x004, |
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MAP_DEF_VALUE_TYPE = 0x008, |
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MAP_DEF_VALUE_SIZE = 0x010, |
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MAP_DEF_MAX_ENTRIES = 0x020, |
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MAP_DEF_MAP_FLAGS = 0x040, |
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MAP_DEF_NUMA_NODE = 0x080, |
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MAP_DEF_PINNING = 0x100, |
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MAP_DEF_INNER_MAP = 0x200, |
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MAP_DEF_MAP_EXTRA = 0x400, |
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MAP_DEF_ALL = 0x7ff, /* combination of all above */ |
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}; |
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struct btf_map_def { |
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enum map_def_parts parts; |
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__u32 map_type; |
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__u32 key_type_id; |
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__u32 key_size; |
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__u32 value_type_id; |
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__u32 value_size; |
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__u32 max_entries; |
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__u32 map_flags; |
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__u32 numa_node; |
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__u32 pinning; |
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__u64 map_extra; |
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}; |
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int parse_btf_map_def(const char *map_name, struct btf *btf, |
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const struct btf_type *def_t, bool strict, |
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struct btf_map_def *map_def, struct btf_map_def *inner_def); |
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void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, |
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size_t cur_cnt, size_t max_cnt, size_t add_cnt); |
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int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt); |
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static inline bool libbpf_is_mem_zeroed(const char *p, ssize_t len) |
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{ |
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while (len > 0) { |
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if (*p) |
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return false; |
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p++; |
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len--; |
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} |
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return true; |
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} |
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static inline bool libbpf_validate_opts(const char *opts, |
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size_t opts_sz, size_t user_sz, |
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const char *type_name) |
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{ |
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if (user_sz < sizeof(size_t)) { |
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pr_warn("%s size (%zu) is too small\n", type_name, user_sz); |
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return false; |
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} |
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if (!libbpf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) { |
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pr_warn("%s has non-zero extra bytes\n", type_name); |
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return false; |
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} |
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return true; |
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} |
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#define OPTS_VALID(opts, type) \ |
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(!(opts) || libbpf_validate_opts((const char *)opts, \ |
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offsetofend(struct type, \ |
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type##__last_field), \ |
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(opts)->sz, #type)) |
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#define OPTS_HAS(opts, field) \ |
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((opts) && opts->sz >= offsetofend(typeof(*(opts)), field)) |
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#define OPTS_GET(opts, field, fallback_value) \ |
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(OPTS_HAS(opts, field) ? (opts)->field : fallback_value) |
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#define OPTS_SET(opts, field, value) \ |
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do { \ |
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if (OPTS_HAS(opts, field)) \ |
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(opts)->field = value; \ |
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} while (0) |
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#define OPTS_ZEROED(opts, last_nonzero_field) \ |
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({ \ |
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ssize_t __off = offsetofend(typeof(*(opts)), last_nonzero_field); \ |
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!(opts) || libbpf_is_mem_zeroed((const void *)opts + __off, \ |
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(opts)->sz - __off); \ |
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}) |
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enum kern_feature_id { |
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/* v4.14: kernel support for program & map names. */ |
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FEAT_PROG_NAME, |
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/* v5.2: kernel support for global data sections. */ |
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FEAT_GLOBAL_DATA, |
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/* BTF support */ |
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FEAT_BTF, |
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/* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */ |
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FEAT_BTF_FUNC, |
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/* BTF_KIND_VAR and BTF_KIND_DATASEC support */ |
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FEAT_BTF_DATASEC, |
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/* BTF_FUNC_GLOBAL is supported */ |
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FEAT_BTF_GLOBAL_FUNC, |
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/* BPF_F_MMAPABLE is supported for arrays */ |
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FEAT_ARRAY_MMAP, |
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/* kernel support for expected_attach_type in BPF_PROG_LOAD */ |
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FEAT_EXP_ATTACH_TYPE, |
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/* bpf_probe_read_{kernel,user}[_str] helpers */ |
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FEAT_PROBE_READ_KERN, |
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/* BPF_PROG_BIND_MAP is supported */ |
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FEAT_PROG_BIND_MAP, |
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/* Kernel support for module BTFs */ |
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FEAT_MODULE_BTF, |
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/* BTF_KIND_FLOAT support */ |
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FEAT_BTF_FLOAT, |
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/* BPF perf link support */ |
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FEAT_PERF_LINK, |
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/* BTF_KIND_DECL_TAG support */ |
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FEAT_BTF_DECL_TAG, |
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/* BTF_KIND_TYPE_TAG support */ |
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FEAT_BTF_TYPE_TAG, |
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/* memcg-based accounting for BPF maps and progs */ |
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FEAT_MEMCG_ACCOUNT, |
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__FEAT_CNT, |
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}; |
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int probe_memcg_account(void); |
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bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id); |
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int bump_rlimit_memlock(void); |
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int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz); |
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int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz); |
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int libbpf__load_raw_btf(const char *raw_types, size_t types_len, |
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const char *str_sec, size_t str_len); |
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int btf_load_into_kernel(struct btf *btf, char *log_buf, size_t log_sz, __u32 log_level); |
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struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf); |
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void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type, |
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const char **prefix, int *kind); |
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struct btf_ext_info { |
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/* |
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* info points to the individual info section (e.g. func_info and |
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* line_info) from the .BTF.ext. It does not include the __u32 rec_size. |
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*/ |
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void *info; |
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__u32 rec_size; |
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__u32 len; |
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}; |
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#define for_each_btf_ext_sec(seg, sec) \ |
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for (sec = (seg)->info; \ |
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(void *)sec < (seg)->info + (seg)->len; \ |
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sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \ |
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(seg)->rec_size * sec->num_info) |
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#define for_each_btf_ext_rec(seg, sec, i, rec) \ |
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for (i = 0, rec = (void *)&(sec)->data; \ |
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i < (sec)->num_info; \ |
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i++, rec = (void *)rec + (seg)->rec_size) |
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/* |
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* The .BTF.ext ELF section layout defined as |
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* struct btf_ext_header |
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* func_info subsection |
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* |
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* The func_info subsection layout: |
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* record size for struct bpf_func_info in the func_info subsection |
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* struct btf_sec_func_info for section #1 |
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* a list of bpf_func_info records for section #1 |
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* where struct bpf_func_info mimics one in include/uapi/linux/bpf.h |
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* but may not be identical |
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* struct btf_sec_func_info for section #2 |
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* a list of bpf_func_info records for section #2 |
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* ...... |
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* |
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* Note that the bpf_func_info record size in .BTF.ext may not |
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* be the same as the one defined in include/uapi/linux/bpf.h. |
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* The loader should ensure that record_size meets minimum |
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* requirement and pass the record as is to the kernel. The |
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* kernel will handle the func_info properly based on its contents. |
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*/ |
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struct btf_ext_header { |
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__u16 magic; |
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__u8 version; |
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__u8 flags; |
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__u32 hdr_len; |
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/* All offsets are in bytes relative to the end of this header */ |
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__u32 func_info_off; |
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__u32 func_info_len; |
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__u32 line_info_off; |
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__u32 line_info_len; |
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/* optional part of .BTF.ext header */ |
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__u32 core_relo_off; |
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__u32 core_relo_len; |
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}; |
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struct btf_ext { |
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union { |
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struct btf_ext_header *hdr; |
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void *data; |
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}; |
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struct btf_ext_info func_info; |
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struct btf_ext_info line_info; |
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struct btf_ext_info core_relo_info; |
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__u32 data_size; |
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}; |
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struct btf_ext_info_sec { |
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__u32 sec_name_off; |
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__u32 num_info; |
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/* Followed by num_info * record_size number of bytes */ |
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__u8 data[]; |
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}; |
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/* The minimum bpf_func_info checked by the loader */ |
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struct bpf_func_info_min { |
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__u32 insn_off; |
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__u32 type_id; |
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}; |
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/* The minimum bpf_line_info checked by the loader */ |
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struct bpf_line_info_min { |
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__u32 insn_off; |
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__u32 file_name_off; |
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__u32 line_off; |
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__u32 line_col; |
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}; |
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typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx); |
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typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx); |
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int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ctx); |
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int btf_type_visit_str_offs(struct btf_type *t, str_off_visit_fn visit, void *ctx); |
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int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx); |
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int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx); |
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__s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name, |
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__u32 kind); |
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extern enum libbpf_strict_mode libbpf_mode; |
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/* handle direct returned errors */ |
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static inline int libbpf_err(int ret) |
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{ |
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if (ret < 0) |
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errno = -ret; |
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return ret; |
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} |
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/* handle errno-based (e.g., syscall or libc) errors according to libbpf's |
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* strict mode settings |
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*/ |
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static inline int libbpf_err_errno(int ret) |
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{ |
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if (libbpf_mode & LIBBPF_STRICT_DIRECT_ERRS) |
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/* errno is already assumed to be set on error */ |
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return ret < 0 ? -errno : ret; |
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/* legacy: on error return -1 directly and don't touch errno */ |
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return ret; |
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} |
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/* handle error for pointer-returning APIs, err is assumed to be < 0 always */ |
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static inline void *libbpf_err_ptr(int err) |
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{ |
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/* set errno on error, this doesn't break anything */ |
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errno = -err; |
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if (libbpf_mode & LIBBPF_STRICT_CLEAN_PTRS) |
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return NULL; |
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/* legacy: encode err as ptr */ |
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return ERR_PTR(err); |
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} |
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/* handle pointer-returning APIs' error handling */ |
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static inline void *libbpf_ptr(void *ret) |
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{ |
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/* set errno on error, this doesn't break anything */ |
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if (IS_ERR(ret)) |
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errno = -PTR_ERR(ret); |
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if (libbpf_mode & LIBBPF_STRICT_CLEAN_PTRS) |
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return IS_ERR(ret) ? NULL : ret; |
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/* legacy: pass-through original pointer */ |
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return ret; |
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} |
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static inline bool str_is_empty(const char *s) |
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{ |
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return !s || !s[0]; |
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} |
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static inline bool is_ldimm64_insn(struct bpf_insn *insn) |
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{ |
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return insn->code == (BPF_LD | BPF_IMM | BPF_DW); |
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} |
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/* if fd is stdin, stdout, or stderr, dup to a fd greater than 2 |
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* Takes ownership of the fd passed in, and closes it if calling |
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* fcntl(fd, F_DUPFD_CLOEXEC, 3). |
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*/ |
|
static inline int ensure_good_fd(int fd) |
|
{ |
|
int old_fd = fd, saved_errno; |
|
|
|
if (fd < 0) |
|
return fd; |
|
if (fd < 3) { |
|
fd = fcntl(fd, F_DUPFD_CLOEXEC, 3); |
|
saved_errno = errno; |
|
close(old_fd); |
|
if (fd < 0) { |
|
pr_warn("failed to dup FD %d to FD > 2: %d\n", old_fd, -saved_errno); |
|
errno = saved_errno; |
|
} |
|
} |
|
return fd; |
|
} |
|
|
|
#endif /* __LIBBPF_LIBBPF_INTERNAL_H */
|
|
|