1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2
3 /*
4 * Internal libbpf helpers.
5 *
6 * Copyright (c) 2019 Facebook
7 */
8
9 #ifndef __LIBBPF_LIBBPF_INTERNAL_H
10 #define __LIBBPF_LIBBPF_INTERNAL_H
11
12 #include <stdlib.h>
13 #include <limits.h>
14 #include <errno.h>
15 #include <linux/err.h>
16 #include <fcntl.h>
17 #include <unistd.h>
18 #include "relo_core.h"
19
20 /* make sure libbpf doesn't use kernel-only integer typedefs */
21 #pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
22
23 /* prevent accidental re-addition of reallocarray() */
24 #pragma GCC poison reallocarray
25
26 #include "libbpf.h"
27 #include "btf.h"
28
29 #ifndef EM_BPF
30 #define EM_BPF 247
31 #endif
32
33 #ifndef R_BPF_64_64
34 #define R_BPF_64_64 1
35 #endif
36 #ifndef R_BPF_64_ABS64
37 #define R_BPF_64_ABS64 2
38 #endif
39 #ifndef R_BPF_64_ABS32
40 #define R_BPF_64_ABS32 3
41 #endif
42 #ifndef R_BPF_64_32
43 #define R_BPF_64_32 10
44 #endif
45
46 #ifndef SHT_LLVM_ADDRSIG
47 #define SHT_LLVM_ADDRSIG 0x6FFF4C03
48 #endif
49
50 /* if libelf is old and doesn't support mmap(), fall back to read() */
51 #ifndef ELF_C_READ_MMAP
52 #define ELF_C_READ_MMAP ELF_C_READ
53 #endif
54
55 /* Older libelf all end up in this expression, for both 32 and 64 bit */
56 #ifndef ELF64_ST_VISIBILITY
57 #define ELF64_ST_VISIBILITY(o) ((o) & 0x03)
58 #endif
59
60 #define BTF_INFO_ENC(kind, kind_flag, vlen) \
61 ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
62 #define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type)
63 #define BTF_INT_ENC(encoding, bits_offset, nr_bits) \
64 ((encoding) << 24 | (bits_offset) << 16 | (nr_bits))
65 #define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \
66 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \
67 BTF_INT_ENC(encoding, bits_offset, bits)
68 #define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset)
69 #define BTF_PARAM_ENC(name, type) (name), (type)
70 #define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size)
71 #define BTF_TYPE_FLOAT_ENC(name, sz) \
72 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz)
73 #define BTF_TYPE_DECL_TAG_ENC(value, type, component_idx) \
74 BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_DECL_TAG, 0, 0), type), (component_idx)
75 #define BTF_TYPE_TYPE_TAG_ENC(value, type) \
76 BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TYPE_TAG, 0, 0), type)
77
78 #ifndef likely
79 #define likely(x) __builtin_expect(!!(x), 1)
80 #endif
81 #ifndef unlikely
82 #define unlikely(x) __builtin_expect(!!(x), 0)
83 #endif
84 #ifndef min
85 # define min(x, y) ((x) < (y) ? (x) : (y))
86 #endif
87 #ifndef max
88 # define max(x, y) ((x) < (y) ? (y) : (x))
89 #endif
90 #ifndef offsetofend
91 # define offsetofend(TYPE, FIELD) \
92 (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD))
93 #endif
94 #ifndef __alias
95 #define __alias(symbol) __attribute__((alias(#symbol)))
96 #endif
97
98 /* Check whether a string `str` has prefix `pfx`, regardless if `pfx` is
99 * a string literal known at compilation time or char * pointer known only at
100 * runtime.
101 */
102 #define str_has_pfx(str, pfx) \
103 (strncmp(str, pfx, __builtin_constant_p(pfx) ? sizeof(pfx) - 1 : strlen(pfx)) == 0)
104
105 /* suffix check */
str_has_sfx(const char * str,const char * sfx)106 static inline bool str_has_sfx(const char *str, const char *sfx)
107 {
108 size_t str_len = strlen(str);
109 size_t sfx_len = strlen(sfx);
110
111 if (sfx_len > str_len)
112 return false;
113 return strcmp(str + str_len - sfx_len, sfx) == 0;
114 }
115
116 /* Symbol versioning is different between static and shared library.
117 * Properly versioned symbols are needed for shared library, but
118 * only the symbol of the new version is needed for static library.
119 * Starting with GNU C 10, use symver attribute instead of .symver assembler
120 * directive, which works better with GCC LTO builds.
121 */
122 #if defined(SHARED) && defined(__GNUC__) && __GNUC__ >= 10
123
124 #define DEFAULT_VERSION(internal_name, api_name, version) \
125 __attribute__((symver(#api_name "@@" #version)))
126 #define COMPAT_VERSION(internal_name, api_name, version) \
127 __attribute__((symver(#api_name "@" #version)))
128
129 #elif defined(SHARED)
130
131 #define COMPAT_VERSION(internal_name, api_name, version) \
132 asm(".symver " #internal_name "," #api_name "@" #version);
133 #define DEFAULT_VERSION(internal_name, api_name, version) \
134 asm(".symver " #internal_name "," #api_name "@@" #version);
135
136 #else /* !SHARED */
137
138 #define COMPAT_VERSION(internal_name, api_name, version)
139 #define DEFAULT_VERSION(internal_name, api_name, version) \
140 extern typeof(internal_name) api_name \
141 __attribute__((alias(#internal_name)));
142
143 #endif
144
145 extern void libbpf_print(enum libbpf_print_level level,
146 const char *format, ...)
147 __attribute__((format(printf, 2, 3)));
148
149 #define __pr(level, fmt, ...) \
150 do { \
151 libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \
152 } while (0)
153
154 #define pr_warn(fmt, ...) __pr(LIBBPF_WARN, fmt, ##__VA_ARGS__)
155 #define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__)
156 #define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__)
157
158 #ifndef __has_builtin
159 #define __has_builtin(x) 0
160 #endif
161
162 struct bpf_link {
163 int (*detach)(struct bpf_link *link);
164 void (*dealloc)(struct bpf_link *link);
165 char *pin_path; /* NULL, if not pinned */
166 int fd; /* hook FD, -1 if not applicable */
167 bool disconnected;
168 };
169
170 /*
171 * Re-implement glibc's reallocarray() for libbpf internal-only use.
172 * reallocarray(), unfortunately, is not available in all versions of glibc,
173 * so requires extra feature detection and using reallocarray() stub from
174 * <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates
175 * build of libbpf unnecessarily and is just a maintenance burden. Instead,
176 * it's trivial to implement libbpf-specific internal version and use it
177 * throughout libbpf.
178 */
libbpf_reallocarray(void * ptr,size_t nmemb,size_t size)179 static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size)
180 {
181 size_t total;
182
183 #if __has_builtin(__builtin_mul_overflow)
184 if (unlikely(__builtin_mul_overflow(nmemb, size, &total)))
185 return NULL;
186 #else
187 if (size == 0 || nmemb > ULONG_MAX / size)
188 return NULL;
189 total = nmemb * size;
190 #endif
191 return realloc(ptr, total);
192 }
193
194 /* Copy up to sz - 1 bytes from zero-terminated src string and ensure that dst
195 * is zero-terminated string no matter what (unless sz == 0, in which case
196 * it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but differs
197 * in what is returned. Given this is internal helper, it's trivial to extend
198 * this, when necessary. Use this instead of strncpy inside libbpf source code.
199 */
libbpf_strlcpy(char * dst,const char * src,size_t sz)200 static inline void libbpf_strlcpy(char *dst, const char *src, size_t sz)
201 {
202 size_t i;
203
204 if (sz == 0)
205 return;
206
207 sz--;
208 for (i = 0; i < sz && src[i]; i++)
209 dst[i] = src[i];
210 dst[i] = '\0';
211 }
212
213 __u32 get_kernel_version(void);
214
215 struct btf;
216 struct btf_type;
217
218 struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id);
219 const char *btf_kind_str(const struct btf_type *t);
220 const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id);
221
btf_func_linkage(const struct btf_type * t)222 static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t)
223 {
224 return (enum btf_func_linkage)(int)btf_vlen(t);
225 }
226
btf_type_info(int kind,int vlen,int kflag)227 static inline __u32 btf_type_info(int kind, int vlen, int kflag)
228 {
229 return (kflag << 31) | (kind << 24) | vlen;
230 }
231
232 enum map_def_parts {
233 MAP_DEF_MAP_TYPE = 0x001,
234 MAP_DEF_KEY_TYPE = 0x002,
235 MAP_DEF_KEY_SIZE = 0x004,
236 MAP_DEF_VALUE_TYPE = 0x008,
237 MAP_DEF_VALUE_SIZE = 0x010,
238 MAP_DEF_MAX_ENTRIES = 0x020,
239 MAP_DEF_MAP_FLAGS = 0x040,
240 MAP_DEF_NUMA_NODE = 0x080,
241 MAP_DEF_PINNING = 0x100,
242 MAP_DEF_INNER_MAP = 0x200,
243 MAP_DEF_MAP_EXTRA = 0x400,
244
245 MAP_DEF_ALL = 0x7ff, /* combination of all above */
246 };
247
248 struct btf_map_def {
249 enum map_def_parts parts;
250 __u32 map_type;
251 __u32 key_type_id;
252 __u32 key_size;
253 __u32 value_type_id;
254 __u32 value_size;
255 __u32 max_entries;
256 __u32 map_flags;
257 __u32 numa_node;
258 __u32 pinning;
259 __u64 map_extra;
260 };
261
262 int parse_btf_map_def(const char *map_name, struct btf *btf,
263 const struct btf_type *def_t, bool strict,
264 struct btf_map_def *map_def, struct btf_map_def *inner_def);
265
266 void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz,
267 size_t cur_cnt, size_t max_cnt, size_t add_cnt);
268 int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt);
269
libbpf_is_mem_zeroed(const char * p,ssize_t len)270 static inline bool libbpf_is_mem_zeroed(const char *p, ssize_t len)
271 {
272 while (len > 0) {
273 if (*p)
274 return false;
275 p++;
276 len--;
277 }
278 return true;
279 }
280
libbpf_validate_opts(const char * opts,size_t opts_sz,size_t user_sz,const char * type_name)281 static inline bool libbpf_validate_opts(const char *opts,
282 size_t opts_sz, size_t user_sz,
283 const char *type_name)
284 {
285 if (user_sz < sizeof(size_t)) {
286 pr_warn("%s size (%zu) is too small\n", type_name, user_sz);
287 return false;
288 }
289 if (!libbpf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) {
290 pr_warn("%s has non-zero extra bytes\n", type_name);
291 return false;
292 }
293 return true;
294 }
295
296 #define OPTS_VALID(opts, type) \
297 (!(opts) || libbpf_validate_opts((const char *)opts, \
298 offsetofend(struct type, \
299 type##__last_field), \
300 (opts)->sz, #type))
301 #define OPTS_HAS(opts, field) \
302 ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field))
303 #define OPTS_GET(opts, field, fallback_value) \
304 (OPTS_HAS(opts, field) ? (opts)->field : fallback_value)
305 #define OPTS_SET(opts, field, value) \
306 do { \
307 if (OPTS_HAS(opts, field)) \
308 (opts)->field = value; \
309 } while (0)
310
311 #define OPTS_ZEROED(opts, last_nonzero_field) \
312 ({ \
313 ssize_t __off = offsetofend(typeof(*(opts)), last_nonzero_field); \
314 !(opts) || libbpf_is_mem_zeroed((const void *)opts + __off, \
315 (opts)->sz - __off); \
316 })
317
318 enum kern_feature_id {
319 /* v4.14: kernel support for program & map names. */
320 FEAT_PROG_NAME,
321 /* v5.2: kernel support for global data sections. */
322 FEAT_GLOBAL_DATA,
323 /* BTF support */
324 FEAT_BTF,
325 /* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
326 FEAT_BTF_FUNC,
327 /* BTF_KIND_VAR and BTF_KIND_DATASEC support */
328 FEAT_BTF_DATASEC,
329 /* BTF_FUNC_GLOBAL is supported */
330 FEAT_BTF_GLOBAL_FUNC,
331 /* BPF_F_MMAPABLE is supported for arrays */
332 FEAT_ARRAY_MMAP,
333 /* kernel support for expected_attach_type in BPF_PROG_LOAD */
334 FEAT_EXP_ATTACH_TYPE,
335 /* bpf_probe_read_{kernel,user}[_str] helpers */
336 FEAT_PROBE_READ_KERN,
337 /* BPF_PROG_BIND_MAP is supported */
338 FEAT_PROG_BIND_MAP,
339 /* Kernel support for module BTFs */
340 FEAT_MODULE_BTF,
341 /* BTF_KIND_FLOAT support */
342 FEAT_BTF_FLOAT,
343 /* BPF perf link support */
344 FEAT_PERF_LINK,
345 /* BTF_KIND_DECL_TAG support */
346 FEAT_BTF_DECL_TAG,
347 /* BTF_KIND_TYPE_TAG support */
348 FEAT_BTF_TYPE_TAG,
349 /* memcg-based accounting for BPF maps and progs */
350 FEAT_MEMCG_ACCOUNT,
351 /* BPF cookie (bpf_get_attach_cookie() BPF helper) support */
352 FEAT_BPF_COOKIE,
353 /* BTF_KIND_ENUM64 support and BTF_KIND_ENUM kflag support */
354 FEAT_BTF_ENUM64,
355 /* Kernel uses syscall wrapper (CONFIG_ARCH_HAS_SYSCALL_WRAPPER) */
356 FEAT_SYSCALL_WRAPPER,
357 __FEAT_CNT,
358 };
359
360 int probe_memcg_account(void);
361 bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id);
362 int bump_rlimit_memlock(void);
363
364 int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz);
365 int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz);
366 int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
367 const char *str_sec, size_t str_len);
368 int btf_load_into_kernel(struct btf *btf, char *log_buf, size_t log_sz, __u32 log_level);
369
370 struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf);
371 void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type,
372 const char **prefix, int *kind);
373
374 struct btf_ext_info {
375 /*
376 * info points to the individual info section (e.g. func_info and
377 * line_info) from the .BTF.ext. It does not include the __u32 rec_size.
378 */
379 void *info;
380 __u32 rec_size;
381 __u32 len;
382 /* optional (maintained internally by libbpf) mapping between .BTF.ext
383 * section and corresponding ELF section. This is used to join
384 * information like CO-RE relocation records with corresponding BPF
385 * programs defined in ELF sections
386 */
387 __u32 *sec_idxs;
388 int sec_cnt;
389 };
390
391 #define for_each_btf_ext_sec(seg, sec) \
392 for (sec = (seg)->info; \
393 (void *)sec < (seg)->info + (seg)->len; \
394 sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \
395 (seg)->rec_size * sec->num_info)
396
397 #define for_each_btf_ext_rec(seg, sec, i, rec) \
398 for (i = 0, rec = (void *)&(sec)->data; \
399 i < (sec)->num_info; \
400 i++, rec = (void *)rec + (seg)->rec_size)
401
402 /*
403 * The .BTF.ext ELF section layout defined as
404 * struct btf_ext_header
405 * func_info subsection
406 *
407 * The func_info subsection layout:
408 * record size for struct bpf_func_info in the func_info subsection
409 * struct btf_sec_func_info for section #1
410 * a list of bpf_func_info records for section #1
411 * where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
412 * but may not be identical
413 * struct btf_sec_func_info for section #2
414 * a list of bpf_func_info records for section #2
415 * ......
416 *
417 * Note that the bpf_func_info record size in .BTF.ext may not
418 * be the same as the one defined in include/uapi/linux/bpf.h.
419 * The loader should ensure that record_size meets minimum
420 * requirement and pass the record as is to the kernel. The
421 * kernel will handle the func_info properly based on its contents.
422 */
423 struct btf_ext_header {
424 __u16 magic;
425 __u8 version;
426 __u8 flags;
427 __u32 hdr_len;
428
429 /* All offsets are in bytes relative to the end of this header */
430 __u32 func_info_off;
431 __u32 func_info_len;
432 __u32 line_info_off;
433 __u32 line_info_len;
434
435 /* optional part of .BTF.ext header */
436 __u32 core_relo_off;
437 __u32 core_relo_len;
438 };
439
440 struct btf_ext {
441 union {
442 struct btf_ext_header *hdr;
443 void *data;
444 };
445 struct btf_ext_info func_info;
446 struct btf_ext_info line_info;
447 struct btf_ext_info core_relo_info;
448 __u32 data_size;
449 };
450
451 struct btf_ext_info_sec {
452 __u32 sec_name_off;
453 __u32 num_info;
454 /* Followed by num_info * record_size number of bytes */
455 __u8 data[];
456 };
457
458 /* The minimum bpf_func_info checked by the loader */
459 struct bpf_func_info_min {
460 __u32 insn_off;
461 __u32 type_id;
462 };
463
464 /* The minimum bpf_line_info checked by the loader */
465 struct bpf_line_info_min {
466 __u32 insn_off;
467 __u32 file_name_off;
468 __u32 line_off;
469 __u32 line_col;
470 };
471
472
473 typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx);
474 typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx);
475 int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ctx);
476 int btf_type_visit_str_offs(struct btf_type *t, str_off_visit_fn visit, void *ctx);
477 int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx);
478 int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx);
479 __s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name,
480 __u32 kind);
481
482 typedef int (*kallsyms_cb_t)(unsigned long long sym_addr, char sym_type,
483 const char *sym_name, void *ctx);
484
485 int libbpf_kallsyms_parse(kallsyms_cb_t cb, void *arg);
486
487 /* handle direct returned errors */
libbpf_err(int ret)488 static inline int libbpf_err(int ret)
489 {
490 if (ret < 0)
491 errno = -ret;
492 return ret;
493 }
494
495 /* handle errno-based (e.g., syscall or libc) errors according to libbpf's
496 * strict mode settings
497 */
libbpf_err_errno(int ret)498 static inline int libbpf_err_errno(int ret)
499 {
500 /* errno is already assumed to be set on error */
501 return ret < 0 ? -errno : ret;
502 }
503
504 /* handle error for pointer-returning APIs, err is assumed to be < 0 always */
libbpf_err_ptr(int err)505 static inline void *libbpf_err_ptr(int err)
506 {
507 /* set errno on error, this doesn't break anything */
508 errno = -err;
509 return NULL;
510 }
511
512 /* handle pointer-returning APIs' error handling */
libbpf_ptr(void * ret)513 static inline void *libbpf_ptr(void *ret)
514 {
515 /* set errno on error, this doesn't break anything */
516 if (IS_ERR(ret))
517 errno = -PTR_ERR(ret);
518
519 return IS_ERR(ret) ? NULL : ret;
520 }
521
str_is_empty(const char * s)522 static inline bool str_is_empty(const char *s)
523 {
524 return !s || !s[0];
525 }
526
is_ldimm64_insn(struct bpf_insn * insn)527 static inline bool is_ldimm64_insn(struct bpf_insn *insn)
528 {
529 return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
530 }
531
532 /* if fd is stdin, stdout, or stderr, dup to a fd greater than 2
533 * Takes ownership of the fd passed in, and closes it if calling
534 * fcntl(fd, F_DUPFD_CLOEXEC, 3).
535 */
ensure_good_fd(int fd)536 static inline int ensure_good_fd(int fd)
537 {
538 int old_fd = fd, saved_errno;
539
540 if (fd < 0)
541 return fd;
542 if (fd < 3) {
543 fd = fcntl(fd, F_DUPFD_CLOEXEC, 3);
544 saved_errno = errno;
545 close(old_fd);
546 if (fd < 0) {
547 pr_warn("failed to dup FD %d to FD > 2: %d\n", old_fd, -saved_errno);
548 errno = saved_errno;
549 }
550 }
551 return fd;
552 }
553
554 /* The following two functions are exposed to bpftool */
555 int bpf_core_add_cands(struct bpf_core_cand *local_cand,
556 size_t local_essent_len,
557 const struct btf *targ_btf,
558 const char *targ_btf_name,
559 int targ_start_id,
560 struct bpf_core_cand_list *cands);
561 void bpf_core_free_cands(struct bpf_core_cand_list *cands);
562
563 struct usdt_manager *usdt_manager_new(struct bpf_object *obj);
564 void usdt_manager_free(struct usdt_manager *man);
565 struct bpf_link * usdt_manager_attach_usdt(struct usdt_manager *man,
566 const struct bpf_program *prog,
567 pid_t pid, const char *path,
568 const char *usdt_provider, const char *usdt_name,
569 __u64 usdt_cookie);
570
is_pow_of_2(size_t x)571 static inline bool is_pow_of_2(size_t x)
572 {
573 return x && (x & (x - 1)) == 0;
574 }
575
576 #define PROG_LOAD_ATTEMPTS 5
577 int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size, int attempts);
578
579 #endif /* __LIBBPF_LIBBPF_INTERNAL_H */
580