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