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[mirror_ubuntu-artful-kernel.git] / tools / lib / bpf / libbpf.c
1 /*
2 * Common eBPF ELF object loading operations.
3 *
4 * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
5 * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
6 * Copyright (C) 2015 Huawei Inc.
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation;
11 * version 2.1 of the License (not later!)
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this program; if not, see <http://www.gnu.org/licenses>
20 */
21
22 #include <stdlib.h>
23 #include <stdio.h>
24 #include <stdarg.h>
25 #include <inttypes.h>
26 #include <string.h>
27 #include <unistd.h>
28 #include <fcntl.h>
29 #include <errno.h>
30 #include <asm/unistd.h>
31 #include <linux/kernel.h>
32 #include <linux/bpf.h>
33 #include <linux/list.h>
34 #include <libelf.h>
35 #include <gelf.h>
36
37 #include "libbpf.h"
38 #include "bpf.h"
39
40 #ifndef EM_BPF
41 #define EM_BPF 247
42 #endif
43
44 #define __printf(a, b) __attribute__((format(printf, a, b)))
45
46 __printf(1, 2)
47 static int __base_pr(const char *format, ...)
48 {
49 va_list args;
50 int err;
51
52 va_start(args, format);
53 err = vfprintf(stderr, format, args);
54 va_end(args);
55 return err;
56 }
57
58 static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr;
59 static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr;
60 static __printf(1, 2) libbpf_print_fn_t __pr_debug;
61
62 #define __pr(func, fmt, ...) \
63 do { \
64 if ((func)) \
65 (func)("libbpf: " fmt, ##__VA_ARGS__); \
66 } while (0)
67
68 #define pr_warning(fmt, ...) __pr(__pr_warning, fmt, ##__VA_ARGS__)
69 #define pr_info(fmt, ...) __pr(__pr_info, fmt, ##__VA_ARGS__)
70 #define pr_debug(fmt, ...) __pr(__pr_debug, fmt, ##__VA_ARGS__)
71
72 void libbpf_set_print(libbpf_print_fn_t warn,
73 libbpf_print_fn_t info,
74 libbpf_print_fn_t debug)
75 {
76 __pr_warning = warn;
77 __pr_info = info;
78 __pr_debug = debug;
79 }
80
81 #define STRERR_BUFSIZE 128
82
83 #define ERRNO_OFFSET(e) ((e) - __LIBBPF_ERRNO__START)
84 #define ERRCODE_OFFSET(c) ERRNO_OFFSET(LIBBPF_ERRNO__##c)
85 #define NR_ERRNO (__LIBBPF_ERRNO__END - __LIBBPF_ERRNO__START)
86
87 static const char *libbpf_strerror_table[NR_ERRNO] = {
88 [ERRCODE_OFFSET(LIBELF)] = "Something wrong in libelf",
89 [ERRCODE_OFFSET(FORMAT)] = "BPF object format invalid",
90 [ERRCODE_OFFSET(KVERSION)] = "'version' section incorrect or lost",
91 [ERRCODE_OFFSET(ENDIAN)] = "Endian mismatch",
92 [ERRCODE_OFFSET(INTERNAL)] = "Internal error in libbpf",
93 [ERRCODE_OFFSET(RELOC)] = "Relocation failed",
94 [ERRCODE_OFFSET(VERIFY)] = "Kernel verifier blocks program loading",
95 [ERRCODE_OFFSET(PROG2BIG)] = "Program too big",
96 [ERRCODE_OFFSET(KVER)] = "Incorrect kernel version",
97 [ERRCODE_OFFSET(PROGTYPE)] = "Kernel doesn't support this program type",
98 };
99
100 int libbpf_strerror(int err, char *buf, size_t size)
101 {
102 if (!buf || !size)
103 return -1;
104
105 err = err > 0 ? err : -err;
106
107 if (err < __LIBBPF_ERRNO__START) {
108 int ret;
109
110 ret = strerror_r(err, buf, size);
111 buf[size - 1] = '\0';
112 return ret;
113 }
114
115 if (err < __LIBBPF_ERRNO__END) {
116 const char *msg;
117
118 msg = libbpf_strerror_table[ERRNO_OFFSET(err)];
119 snprintf(buf, size, "%s", msg);
120 buf[size - 1] = '\0';
121 return 0;
122 }
123
124 snprintf(buf, size, "Unknown libbpf error %d", err);
125 buf[size - 1] = '\0';
126 return -1;
127 }
128
129 #define CHECK_ERR(action, err, out) do { \
130 err = action; \
131 if (err) \
132 goto out; \
133 } while(0)
134
135
136 /* Copied from tools/perf/util/util.h */
137 #ifndef zfree
138 # define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
139 #endif
140
141 #ifndef zclose
142 # define zclose(fd) ({ \
143 int ___err = 0; \
144 if ((fd) >= 0) \
145 ___err = close((fd)); \
146 fd = -1; \
147 ___err; })
148 #endif
149
150 #ifdef HAVE_LIBELF_MMAP_SUPPORT
151 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
152 #else
153 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
154 #endif
155
156 /*
157 * bpf_prog should be a better name but it has been used in
158 * linux/filter.h.
159 */
160 struct bpf_program {
161 /* Index in elf obj file, for relocation use. */
162 int idx;
163 char *section_name;
164 struct bpf_insn *insns;
165 size_t insns_cnt;
166 enum bpf_prog_type type;
167
168 struct {
169 int insn_idx;
170 int map_idx;
171 } *reloc_desc;
172 int nr_reloc;
173
174 struct {
175 int nr;
176 int *fds;
177 } instances;
178 bpf_program_prep_t preprocessor;
179
180 struct bpf_object *obj;
181 void *priv;
182 bpf_program_clear_priv_t clear_priv;
183 };
184
185 struct bpf_map {
186 int fd;
187 char *name;
188 size_t offset;
189 struct bpf_map_def def;
190 void *priv;
191 bpf_map_clear_priv_t clear_priv;
192 };
193
194 static LIST_HEAD(bpf_objects_list);
195
196 struct bpf_object {
197 char license[64];
198 u32 kern_version;
199
200 struct bpf_program *programs;
201 size_t nr_programs;
202 struct bpf_map *maps;
203 size_t nr_maps;
204
205 bool loaded;
206
207 /*
208 * Information when doing elf related work. Only valid if fd
209 * is valid.
210 */
211 struct {
212 int fd;
213 void *obj_buf;
214 size_t obj_buf_sz;
215 Elf *elf;
216 GElf_Ehdr ehdr;
217 Elf_Data *symbols;
218 size_t strtabidx;
219 struct {
220 GElf_Shdr shdr;
221 Elf_Data *data;
222 } *reloc;
223 int nr_reloc;
224 int maps_shndx;
225 } efile;
226 /*
227 * All loaded bpf_object is linked in a list, which is
228 * hidden to caller. bpf_objects__<func> handlers deal with
229 * all objects.
230 */
231 struct list_head list;
232
233 void *priv;
234 bpf_object_clear_priv_t clear_priv;
235
236 char path[];
237 };
238 #define obj_elf_valid(o) ((o)->efile.elf)
239
240 static void bpf_program__unload(struct bpf_program *prog)
241 {
242 int i;
243
244 if (!prog)
245 return;
246
247 /*
248 * If the object is opened but the program was never loaded,
249 * it is possible that prog->instances.nr == -1.
250 */
251 if (prog->instances.nr > 0) {
252 for (i = 0; i < prog->instances.nr; i++)
253 zclose(prog->instances.fds[i]);
254 } else if (prog->instances.nr != -1) {
255 pr_warning("Internal error: instances.nr is %d\n",
256 prog->instances.nr);
257 }
258
259 prog->instances.nr = -1;
260 zfree(&prog->instances.fds);
261 }
262
263 static void bpf_program__exit(struct bpf_program *prog)
264 {
265 if (!prog)
266 return;
267
268 if (prog->clear_priv)
269 prog->clear_priv(prog, prog->priv);
270
271 prog->priv = NULL;
272 prog->clear_priv = NULL;
273
274 bpf_program__unload(prog);
275 zfree(&prog->section_name);
276 zfree(&prog->insns);
277 zfree(&prog->reloc_desc);
278
279 prog->nr_reloc = 0;
280 prog->insns_cnt = 0;
281 prog->idx = -1;
282 }
283
284 static int
285 bpf_program__init(void *data, size_t size, char *name, int idx,
286 struct bpf_program *prog)
287 {
288 if (size < sizeof(struct bpf_insn)) {
289 pr_warning("corrupted section '%s'\n", name);
290 return -EINVAL;
291 }
292
293 bzero(prog, sizeof(*prog));
294
295 prog->section_name = strdup(name);
296 if (!prog->section_name) {
297 pr_warning("failed to alloc name for prog %s\n",
298 name);
299 goto errout;
300 }
301
302 prog->insns = malloc(size);
303 if (!prog->insns) {
304 pr_warning("failed to alloc insns for %s\n", name);
305 goto errout;
306 }
307 prog->insns_cnt = size / sizeof(struct bpf_insn);
308 memcpy(prog->insns, data,
309 prog->insns_cnt * sizeof(struct bpf_insn));
310 prog->idx = idx;
311 prog->instances.fds = NULL;
312 prog->instances.nr = -1;
313 prog->type = BPF_PROG_TYPE_KPROBE;
314
315 return 0;
316 errout:
317 bpf_program__exit(prog);
318 return -ENOMEM;
319 }
320
321 static int
322 bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
323 char *name, int idx)
324 {
325 struct bpf_program prog, *progs;
326 int nr_progs, err;
327
328 err = bpf_program__init(data, size, name, idx, &prog);
329 if (err)
330 return err;
331
332 progs = obj->programs;
333 nr_progs = obj->nr_programs;
334
335 progs = realloc(progs, sizeof(progs[0]) * (nr_progs + 1));
336 if (!progs) {
337 /*
338 * In this case the original obj->programs
339 * is still valid, so don't need special treat for
340 * bpf_close_object().
341 */
342 pr_warning("failed to alloc a new program '%s'\n",
343 name);
344 bpf_program__exit(&prog);
345 return -ENOMEM;
346 }
347
348 pr_debug("found program %s\n", prog.section_name);
349 obj->programs = progs;
350 obj->nr_programs = nr_progs + 1;
351 prog.obj = obj;
352 progs[nr_progs] = prog;
353 return 0;
354 }
355
356 static struct bpf_object *bpf_object__new(const char *path,
357 void *obj_buf,
358 size_t obj_buf_sz)
359 {
360 struct bpf_object *obj;
361
362 obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
363 if (!obj) {
364 pr_warning("alloc memory failed for %s\n", path);
365 return ERR_PTR(-ENOMEM);
366 }
367
368 strcpy(obj->path, path);
369 obj->efile.fd = -1;
370
371 /*
372 * Caller of this function should also calls
373 * bpf_object__elf_finish() after data collection to return
374 * obj_buf to user. If not, we should duplicate the buffer to
375 * avoid user freeing them before elf finish.
376 */
377 obj->efile.obj_buf = obj_buf;
378 obj->efile.obj_buf_sz = obj_buf_sz;
379 obj->efile.maps_shndx = -1;
380
381 obj->loaded = false;
382
383 INIT_LIST_HEAD(&obj->list);
384 list_add(&obj->list, &bpf_objects_list);
385 return obj;
386 }
387
388 static void bpf_object__elf_finish(struct bpf_object *obj)
389 {
390 if (!obj_elf_valid(obj))
391 return;
392
393 if (obj->efile.elf) {
394 elf_end(obj->efile.elf);
395 obj->efile.elf = NULL;
396 }
397 obj->efile.symbols = NULL;
398
399 zfree(&obj->efile.reloc);
400 obj->efile.nr_reloc = 0;
401 zclose(obj->efile.fd);
402 obj->efile.obj_buf = NULL;
403 obj->efile.obj_buf_sz = 0;
404 }
405
406 static int bpf_object__elf_init(struct bpf_object *obj)
407 {
408 int err = 0;
409 GElf_Ehdr *ep;
410
411 if (obj_elf_valid(obj)) {
412 pr_warning("elf init: internal error\n");
413 return -LIBBPF_ERRNO__LIBELF;
414 }
415
416 if (obj->efile.obj_buf_sz > 0) {
417 /*
418 * obj_buf should have been validated by
419 * bpf_object__open_buffer().
420 */
421 obj->efile.elf = elf_memory(obj->efile.obj_buf,
422 obj->efile.obj_buf_sz);
423 } else {
424 obj->efile.fd = open(obj->path, O_RDONLY);
425 if (obj->efile.fd < 0) {
426 pr_warning("failed to open %s: %s\n", obj->path,
427 strerror(errno));
428 return -errno;
429 }
430
431 obj->efile.elf = elf_begin(obj->efile.fd,
432 LIBBPF_ELF_C_READ_MMAP,
433 NULL);
434 }
435
436 if (!obj->efile.elf) {
437 pr_warning("failed to open %s as ELF file\n",
438 obj->path);
439 err = -LIBBPF_ERRNO__LIBELF;
440 goto errout;
441 }
442
443 if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
444 pr_warning("failed to get EHDR from %s\n",
445 obj->path);
446 err = -LIBBPF_ERRNO__FORMAT;
447 goto errout;
448 }
449 ep = &obj->efile.ehdr;
450
451 /* Old LLVM set e_machine to EM_NONE */
452 if ((ep->e_type != ET_REL) || (ep->e_machine && (ep->e_machine != EM_BPF))) {
453 pr_warning("%s is not an eBPF object file\n",
454 obj->path);
455 err = -LIBBPF_ERRNO__FORMAT;
456 goto errout;
457 }
458
459 return 0;
460 errout:
461 bpf_object__elf_finish(obj);
462 return err;
463 }
464
465 static int
466 bpf_object__check_endianness(struct bpf_object *obj)
467 {
468 static unsigned int const endian = 1;
469
470 switch (obj->efile.ehdr.e_ident[EI_DATA]) {
471 case ELFDATA2LSB:
472 /* We are big endian, BPF obj is little endian. */
473 if (*(unsigned char const *)&endian != 1)
474 goto mismatch;
475 break;
476
477 case ELFDATA2MSB:
478 /* We are little endian, BPF obj is big endian. */
479 if (*(unsigned char const *)&endian != 0)
480 goto mismatch;
481 break;
482 default:
483 return -LIBBPF_ERRNO__ENDIAN;
484 }
485
486 return 0;
487
488 mismatch:
489 pr_warning("Error: endianness mismatch.\n");
490 return -LIBBPF_ERRNO__ENDIAN;
491 }
492
493 static int
494 bpf_object__init_license(struct bpf_object *obj,
495 void *data, size_t size)
496 {
497 memcpy(obj->license, data,
498 min(size, sizeof(obj->license) - 1));
499 pr_debug("license of %s is %s\n", obj->path, obj->license);
500 return 0;
501 }
502
503 static int
504 bpf_object__init_kversion(struct bpf_object *obj,
505 void *data, size_t size)
506 {
507 u32 kver;
508
509 if (size != sizeof(kver)) {
510 pr_warning("invalid kver section in %s\n", obj->path);
511 return -LIBBPF_ERRNO__FORMAT;
512 }
513 memcpy(&kver, data, sizeof(kver));
514 obj->kern_version = kver;
515 pr_debug("kernel version of %s is %x\n", obj->path,
516 obj->kern_version);
517 return 0;
518 }
519
520 static int
521 bpf_object__validate_maps(struct bpf_object *obj)
522 {
523 int i;
524
525 /*
526 * If there's only 1 map, the only error case should have been
527 * catched in bpf_object__init_maps().
528 */
529 if (!obj->maps || !obj->nr_maps || (obj->nr_maps == 1))
530 return 0;
531
532 for (i = 1; i < obj->nr_maps; i++) {
533 const struct bpf_map *a = &obj->maps[i - 1];
534 const struct bpf_map *b = &obj->maps[i];
535
536 if (b->offset - a->offset < sizeof(struct bpf_map_def)) {
537 pr_warning("corrupted map section in %s: map \"%s\" too small\n",
538 obj->path, a->name);
539 return -EINVAL;
540 }
541 }
542 return 0;
543 }
544
545 static int compare_bpf_map(const void *_a, const void *_b)
546 {
547 const struct bpf_map *a = _a;
548 const struct bpf_map *b = _b;
549
550 return a->offset - b->offset;
551 }
552
553 static int
554 bpf_object__init_maps(struct bpf_object *obj)
555 {
556 int i, map_idx, nr_maps = 0;
557 Elf_Scn *scn;
558 Elf_Data *data;
559 Elf_Data *symbols = obj->efile.symbols;
560
561 if (obj->efile.maps_shndx < 0)
562 return -EINVAL;
563 if (!symbols)
564 return -EINVAL;
565
566 scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx);
567 if (scn)
568 data = elf_getdata(scn, NULL);
569 if (!scn || !data) {
570 pr_warning("failed to get Elf_Data from map section %d\n",
571 obj->efile.maps_shndx);
572 return -EINVAL;
573 }
574
575 /*
576 * Count number of maps. Each map has a name.
577 * Array of maps is not supported: only the first element is
578 * considered.
579 *
580 * TODO: Detect array of map and report error.
581 */
582 for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
583 GElf_Sym sym;
584
585 if (!gelf_getsym(symbols, i, &sym))
586 continue;
587 if (sym.st_shndx != obj->efile.maps_shndx)
588 continue;
589 nr_maps++;
590 }
591
592 /* Alloc obj->maps and fill nr_maps. */
593 pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path,
594 nr_maps, data->d_size);
595
596 if (!nr_maps)
597 return 0;
598
599 obj->maps = calloc(nr_maps, sizeof(obj->maps[0]));
600 if (!obj->maps) {
601 pr_warning("alloc maps for object failed\n");
602 return -ENOMEM;
603 }
604 obj->nr_maps = nr_maps;
605
606 /*
607 * fill all fd with -1 so won't close incorrect
608 * fd (fd=0 is stdin) when failure (zclose won't close
609 * negative fd)).
610 */
611 for (i = 0; i < nr_maps; i++)
612 obj->maps[i].fd = -1;
613
614 /*
615 * Fill obj->maps using data in "maps" section.
616 */
617 for (i = 0, map_idx = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
618 GElf_Sym sym;
619 const char *map_name;
620 struct bpf_map_def *def;
621
622 if (!gelf_getsym(symbols, i, &sym))
623 continue;
624 if (sym.st_shndx != obj->efile.maps_shndx)
625 continue;
626
627 map_name = elf_strptr(obj->efile.elf,
628 obj->efile.strtabidx,
629 sym.st_name);
630 obj->maps[map_idx].offset = sym.st_value;
631 if (sym.st_value + sizeof(struct bpf_map_def) > data->d_size) {
632 pr_warning("corrupted maps section in %s: last map \"%s\" too small\n",
633 obj->path, map_name);
634 return -EINVAL;
635 }
636
637 obj->maps[map_idx].name = strdup(map_name);
638 if (!obj->maps[map_idx].name) {
639 pr_warning("failed to alloc map name\n");
640 return -ENOMEM;
641 }
642 pr_debug("map %d is \"%s\"\n", map_idx,
643 obj->maps[map_idx].name);
644 def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
645 obj->maps[map_idx].def = *def;
646 map_idx++;
647 }
648
649 qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]), compare_bpf_map);
650 return bpf_object__validate_maps(obj);
651 }
652
653 static int bpf_object__elf_collect(struct bpf_object *obj)
654 {
655 Elf *elf = obj->efile.elf;
656 GElf_Ehdr *ep = &obj->efile.ehdr;
657 Elf_Scn *scn = NULL;
658 int idx = 0, err = 0;
659
660 /* Elf is corrupted/truncated, avoid calling elf_strptr. */
661 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
662 pr_warning("failed to get e_shstrndx from %s\n",
663 obj->path);
664 return -LIBBPF_ERRNO__FORMAT;
665 }
666
667 while ((scn = elf_nextscn(elf, scn)) != NULL) {
668 char *name;
669 GElf_Shdr sh;
670 Elf_Data *data;
671
672 idx++;
673 if (gelf_getshdr(scn, &sh) != &sh) {
674 pr_warning("failed to get section header from %s\n",
675 obj->path);
676 err = -LIBBPF_ERRNO__FORMAT;
677 goto out;
678 }
679
680 name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
681 if (!name) {
682 pr_warning("failed to get section name from %s\n",
683 obj->path);
684 err = -LIBBPF_ERRNO__FORMAT;
685 goto out;
686 }
687
688 data = elf_getdata(scn, 0);
689 if (!data) {
690 pr_warning("failed to get section data from %s(%s)\n",
691 name, obj->path);
692 err = -LIBBPF_ERRNO__FORMAT;
693 goto out;
694 }
695 pr_debug("section %s, size %ld, link %d, flags %lx, type=%d\n",
696 name, (unsigned long)data->d_size,
697 (int)sh.sh_link, (unsigned long)sh.sh_flags,
698 (int)sh.sh_type);
699
700 if (strcmp(name, "license") == 0)
701 err = bpf_object__init_license(obj,
702 data->d_buf,
703 data->d_size);
704 else if (strcmp(name, "version") == 0)
705 err = bpf_object__init_kversion(obj,
706 data->d_buf,
707 data->d_size);
708 else if (strcmp(name, "maps") == 0)
709 obj->efile.maps_shndx = idx;
710 else if (sh.sh_type == SHT_SYMTAB) {
711 if (obj->efile.symbols) {
712 pr_warning("bpf: multiple SYMTAB in %s\n",
713 obj->path);
714 err = -LIBBPF_ERRNO__FORMAT;
715 } else {
716 obj->efile.symbols = data;
717 obj->efile.strtabidx = sh.sh_link;
718 }
719 } else if ((sh.sh_type == SHT_PROGBITS) &&
720 (sh.sh_flags & SHF_EXECINSTR) &&
721 (data->d_size > 0)) {
722 err = bpf_object__add_program(obj, data->d_buf,
723 data->d_size, name, idx);
724 if (err) {
725 char errmsg[STRERR_BUFSIZE];
726
727 strerror_r(-err, errmsg, sizeof(errmsg));
728 pr_warning("failed to alloc program %s (%s): %s",
729 name, obj->path, errmsg);
730 }
731 } else if (sh.sh_type == SHT_REL) {
732 void *reloc = obj->efile.reloc;
733 int nr_reloc = obj->efile.nr_reloc + 1;
734
735 reloc = realloc(reloc,
736 sizeof(*obj->efile.reloc) * nr_reloc);
737 if (!reloc) {
738 pr_warning("realloc failed\n");
739 err = -ENOMEM;
740 } else {
741 int n = nr_reloc - 1;
742
743 obj->efile.reloc = reloc;
744 obj->efile.nr_reloc = nr_reloc;
745
746 obj->efile.reloc[n].shdr = sh;
747 obj->efile.reloc[n].data = data;
748 }
749 }
750 if (err)
751 goto out;
752 }
753
754 if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) {
755 pr_warning("Corrupted ELF file: index of strtab invalid\n");
756 return LIBBPF_ERRNO__FORMAT;
757 }
758 if (obj->efile.maps_shndx >= 0)
759 err = bpf_object__init_maps(obj);
760 out:
761 return err;
762 }
763
764 static struct bpf_program *
765 bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
766 {
767 struct bpf_program *prog;
768 size_t i;
769
770 for (i = 0; i < obj->nr_programs; i++) {
771 prog = &obj->programs[i];
772 if (prog->idx == idx)
773 return prog;
774 }
775 return NULL;
776 }
777
778 static int
779 bpf_program__collect_reloc(struct bpf_program *prog,
780 size_t nr_maps, GElf_Shdr *shdr,
781 Elf_Data *data, Elf_Data *symbols,
782 int maps_shndx)
783 {
784 int i, nrels;
785
786 pr_debug("collecting relocating info for: '%s'\n",
787 prog->section_name);
788 nrels = shdr->sh_size / shdr->sh_entsize;
789
790 prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
791 if (!prog->reloc_desc) {
792 pr_warning("failed to alloc memory in relocation\n");
793 return -ENOMEM;
794 }
795 prog->nr_reloc = nrels;
796
797 for (i = 0; i < nrels; i++) {
798 GElf_Sym sym;
799 GElf_Rel rel;
800 unsigned int insn_idx;
801 struct bpf_insn *insns = prog->insns;
802 size_t map_idx;
803
804 if (!gelf_getrel(data, i, &rel)) {
805 pr_warning("relocation: failed to get %d reloc\n", i);
806 return -LIBBPF_ERRNO__FORMAT;
807 }
808
809 if (!gelf_getsym(symbols,
810 GELF_R_SYM(rel.r_info),
811 &sym)) {
812 pr_warning("relocation: symbol %"PRIx64" not found\n",
813 GELF_R_SYM(rel.r_info));
814 return -LIBBPF_ERRNO__FORMAT;
815 }
816
817 if (sym.st_shndx != maps_shndx) {
818 pr_warning("Program '%s' contains non-map related relo data pointing to section %u\n",
819 prog->section_name, sym.st_shndx);
820 return -LIBBPF_ERRNO__RELOC;
821 }
822
823 insn_idx = rel.r_offset / sizeof(struct bpf_insn);
824 pr_debug("relocation: insn_idx=%u\n", insn_idx);
825
826 if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
827 pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
828 insn_idx, insns[insn_idx].code);
829 return -LIBBPF_ERRNO__RELOC;
830 }
831
832 map_idx = sym.st_value / sizeof(struct bpf_map_def);
833 if (map_idx >= nr_maps) {
834 pr_warning("bpf relocation: map_idx %d large than %d\n",
835 (int)map_idx, (int)nr_maps - 1);
836 return -LIBBPF_ERRNO__RELOC;
837 }
838
839 prog->reloc_desc[i].insn_idx = insn_idx;
840 prog->reloc_desc[i].map_idx = map_idx;
841 }
842 return 0;
843 }
844
845 static int
846 bpf_object__create_maps(struct bpf_object *obj)
847 {
848 unsigned int i;
849
850 for (i = 0; i < obj->nr_maps; i++) {
851 struct bpf_map_def *def = &obj->maps[i].def;
852 int *pfd = &obj->maps[i].fd;
853
854 *pfd = bpf_create_map(def->type,
855 def->key_size,
856 def->value_size,
857 def->max_entries);
858 if (*pfd < 0) {
859 size_t j;
860 int err = *pfd;
861
862 pr_warning("failed to create map: %s\n",
863 strerror(errno));
864 for (j = 0; j < i; j++)
865 zclose(obj->maps[j].fd);
866 return err;
867 }
868 pr_debug("create map %s: fd=%d\n", obj->maps[i].name, *pfd);
869 }
870
871 return 0;
872 }
873
874 static int
875 bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
876 {
877 int i;
878
879 if (!prog || !prog->reloc_desc)
880 return 0;
881
882 for (i = 0; i < prog->nr_reloc; i++) {
883 int insn_idx, map_idx;
884 struct bpf_insn *insns = prog->insns;
885
886 insn_idx = prog->reloc_desc[i].insn_idx;
887 map_idx = prog->reloc_desc[i].map_idx;
888
889 if (insn_idx >= (int)prog->insns_cnt) {
890 pr_warning("relocation out of range: '%s'\n",
891 prog->section_name);
892 return -LIBBPF_ERRNO__RELOC;
893 }
894 insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
895 insns[insn_idx].imm = obj->maps[map_idx].fd;
896 }
897
898 zfree(&prog->reloc_desc);
899 prog->nr_reloc = 0;
900 return 0;
901 }
902
903
904 static int
905 bpf_object__relocate(struct bpf_object *obj)
906 {
907 struct bpf_program *prog;
908 size_t i;
909 int err;
910
911 for (i = 0; i < obj->nr_programs; i++) {
912 prog = &obj->programs[i];
913
914 err = bpf_program__relocate(prog, obj);
915 if (err) {
916 pr_warning("failed to relocate '%s'\n",
917 prog->section_name);
918 return err;
919 }
920 }
921 return 0;
922 }
923
924 static int bpf_object__collect_reloc(struct bpf_object *obj)
925 {
926 int i, err;
927
928 if (!obj_elf_valid(obj)) {
929 pr_warning("Internal error: elf object is closed\n");
930 return -LIBBPF_ERRNO__INTERNAL;
931 }
932
933 for (i = 0; i < obj->efile.nr_reloc; i++) {
934 GElf_Shdr *shdr = &obj->efile.reloc[i].shdr;
935 Elf_Data *data = obj->efile.reloc[i].data;
936 int idx = shdr->sh_info;
937 struct bpf_program *prog;
938 size_t nr_maps = obj->nr_maps;
939
940 if (shdr->sh_type != SHT_REL) {
941 pr_warning("internal error at %d\n", __LINE__);
942 return -LIBBPF_ERRNO__INTERNAL;
943 }
944
945 prog = bpf_object__find_prog_by_idx(obj, idx);
946 if (!prog) {
947 pr_warning("relocation failed: no %d section\n",
948 idx);
949 return -LIBBPF_ERRNO__RELOC;
950 }
951
952 err = bpf_program__collect_reloc(prog, nr_maps,
953 shdr, data,
954 obj->efile.symbols,
955 obj->efile.maps_shndx);
956 if (err)
957 return err;
958 }
959 return 0;
960 }
961
962 static int
963 load_program(enum bpf_prog_type type, struct bpf_insn *insns,
964 int insns_cnt, char *license, u32 kern_version, int *pfd)
965 {
966 int ret;
967 char *log_buf;
968
969 if (!insns || !insns_cnt)
970 return -EINVAL;
971
972 log_buf = malloc(BPF_LOG_BUF_SIZE);
973 if (!log_buf)
974 pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
975
976 ret = bpf_load_program(type, insns, insns_cnt, license,
977 kern_version, log_buf, BPF_LOG_BUF_SIZE);
978
979 if (ret >= 0) {
980 *pfd = ret;
981 ret = 0;
982 goto out;
983 }
984
985 ret = -LIBBPF_ERRNO__LOAD;
986 pr_warning("load bpf program failed: %s\n", strerror(errno));
987
988 if (log_buf && log_buf[0] != '\0') {
989 ret = -LIBBPF_ERRNO__VERIFY;
990 pr_warning("-- BEGIN DUMP LOG ---\n");
991 pr_warning("\n%s\n", log_buf);
992 pr_warning("-- END LOG --\n");
993 } else if (insns_cnt >= BPF_MAXINSNS) {
994 pr_warning("Program too large (%d insns), at most %d insns\n",
995 insns_cnt, BPF_MAXINSNS);
996 ret = -LIBBPF_ERRNO__PROG2BIG;
997 } else {
998 /* Wrong program type? */
999 if (type != BPF_PROG_TYPE_KPROBE) {
1000 int fd;
1001
1002 fd = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,
1003 insns_cnt, license, kern_version,
1004 NULL, 0);
1005 if (fd >= 0) {
1006 close(fd);
1007 ret = -LIBBPF_ERRNO__PROGTYPE;
1008 goto out;
1009 }
1010 }
1011
1012 if (log_buf)
1013 ret = -LIBBPF_ERRNO__KVER;
1014 }
1015
1016 out:
1017 free(log_buf);
1018 return ret;
1019 }
1020
1021 static int
1022 bpf_program__load(struct bpf_program *prog,
1023 char *license, u32 kern_version)
1024 {
1025 int err = 0, fd, i;
1026
1027 if (prog->instances.nr < 0 || !prog->instances.fds) {
1028 if (prog->preprocessor) {
1029 pr_warning("Internal error: can't load program '%s'\n",
1030 prog->section_name);
1031 return -LIBBPF_ERRNO__INTERNAL;
1032 }
1033
1034 prog->instances.fds = malloc(sizeof(int));
1035 if (!prog->instances.fds) {
1036 pr_warning("Not enough memory for BPF fds\n");
1037 return -ENOMEM;
1038 }
1039 prog->instances.nr = 1;
1040 prog->instances.fds[0] = -1;
1041 }
1042
1043 if (!prog->preprocessor) {
1044 if (prog->instances.nr != 1) {
1045 pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n",
1046 prog->section_name, prog->instances.nr);
1047 }
1048 err = load_program(prog->type, prog->insns, prog->insns_cnt,
1049 license, kern_version, &fd);
1050 if (!err)
1051 prog->instances.fds[0] = fd;
1052 goto out;
1053 }
1054
1055 for (i = 0; i < prog->instances.nr; i++) {
1056 struct bpf_prog_prep_result result;
1057 bpf_program_prep_t preprocessor = prog->preprocessor;
1058
1059 bzero(&result, sizeof(result));
1060 err = preprocessor(prog, i, prog->insns,
1061 prog->insns_cnt, &result);
1062 if (err) {
1063 pr_warning("Preprocessing the %dth instance of program '%s' failed\n",
1064 i, prog->section_name);
1065 goto out;
1066 }
1067
1068 if (!result.new_insn_ptr || !result.new_insn_cnt) {
1069 pr_debug("Skip loading the %dth instance of program '%s'\n",
1070 i, prog->section_name);
1071 prog->instances.fds[i] = -1;
1072 if (result.pfd)
1073 *result.pfd = -1;
1074 continue;
1075 }
1076
1077 err = load_program(prog->type, result.new_insn_ptr,
1078 result.new_insn_cnt,
1079 license, kern_version, &fd);
1080
1081 if (err) {
1082 pr_warning("Loading the %dth instance of program '%s' failed\n",
1083 i, prog->section_name);
1084 goto out;
1085 }
1086
1087 if (result.pfd)
1088 *result.pfd = fd;
1089 prog->instances.fds[i] = fd;
1090 }
1091 out:
1092 if (err)
1093 pr_warning("failed to load program '%s'\n",
1094 prog->section_name);
1095 zfree(&prog->insns);
1096 prog->insns_cnt = 0;
1097 return err;
1098 }
1099
1100 static int
1101 bpf_object__load_progs(struct bpf_object *obj)
1102 {
1103 size_t i;
1104 int err;
1105
1106 for (i = 0; i < obj->nr_programs; i++) {
1107 err = bpf_program__load(&obj->programs[i],
1108 obj->license,
1109 obj->kern_version);
1110 if (err)
1111 return err;
1112 }
1113 return 0;
1114 }
1115
1116 static int bpf_object__validate(struct bpf_object *obj)
1117 {
1118 if (obj->kern_version == 0) {
1119 pr_warning("%s doesn't provide kernel version\n",
1120 obj->path);
1121 return -LIBBPF_ERRNO__KVERSION;
1122 }
1123 return 0;
1124 }
1125
1126 static struct bpf_object *
1127 __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz)
1128 {
1129 struct bpf_object *obj;
1130 int err;
1131
1132 if (elf_version(EV_CURRENT) == EV_NONE) {
1133 pr_warning("failed to init libelf for %s\n", path);
1134 return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
1135 }
1136
1137 obj = bpf_object__new(path, obj_buf, obj_buf_sz);
1138 if (IS_ERR(obj))
1139 return obj;
1140
1141 CHECK_ERR(bpf_object__elf_init(obj), err, out);
1142 CHECK_ERR(bpf_object__check_endianness(obj), err, out);
1143 CHECK_ERR(bpf_object__elf_collect(obj), err, out);
1144 CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
1145 CHECK_ERR(bpf_object__validate(obj), err, out);
1146
1147 bpf_object__elf_finish(obj);
1148 return obj;
1149 out:
1150 bpf_object__close(obj);
1151 return ERR_PTR(err);
1152 }
1153
1154 struct bpf_object *bpf_object__open(const char *path)
1155 {
1156 /* param validation */
1157 if (!path)
1158 return NULL;
1159
1160 pr_debug("loading %s\n", path);
1161
1162 return __bpf_object__open(path, NULL, 0);
1163 }
1164
1165 struct bpf_object *bpf_object__open_buffer(void *obj_buf,
1166 size_t obj_buf_sz,
1167 const char *name)
1168 {
1169 char tmp_name[64];
1170
1171 /* param validation */
1172 if (!obj_buf || obj_buf_sz <= 0)
1173 return NULL;
1174
1175 if (!name) {
1176 snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
1177 (unsigned long)obj_buf,
1178 (unsigned long)obj_buf_sz);
1179 tmp_name[sizeof(tmp_name) - 1] = '\0';
1180 name = tmp_name;
1181 }
1182 pr_debug("loading object '%s' from buffer\n",
1183 name);
1184
1185 return __bpf_object__open(name, obj_buf, obj_buf_sz);
1186 }
1187
1188 int bpf_object__unload(struct bpf_object *obj)
1189 {
1190 size_t i;
1191
1192 if (!obj)
1193 return -EINVAL;
1194
1195 for (i = 0; i < obj->nr_maps; i++)
1196 zclose(obj->maps[i].fd);
1197
1198 for (i = 0; i < obj->nr_programs; i++)
1199 bpf_program__unload(&obj->programs[i]);
1200
1201 return 0;
1202 }
1203
1204 int bpf_object__load(struct bpf_object *obj)
1205 {
1206 int err;
1207
1208 if (!obj)
1209 return -EINVAL;
1210
1211 if (obj->loaded) {
1212 pr_warning("object should not be loaded twice\n");
1213 return -EINVAL;
1214 }
1215
1216 obj->loaded = true;
1217
1218 CHECK_ERR(bpf_object__create_maps(obj), err, out);
1219 CHECK_ERR(bpf_object__relocate(obj), err, out);
1220 CHECK_ERR(bpf_object__load_progs(obj), err, out);
1221
1222 return 0;
1223 out:
1224 bpf_object__unload(obj);
1225 pr_warning("failed to load object '%s'\n", obj->path);
1226 return err;
1227 }
1228
1229 void bpf_object__close(struct bpf_object *obj)
1230 {
1231 size_t i;
1232
1233 if (!obj)
1234 return;
1235
1236 if (obj->clear_priv)
1237 obj->clear_priv(obj, obj->priv);
1238
1239 bpf_object__elf_finish(obj);
1240 bpf_object__unload(obj);
1241
1242 for (i = 0; i < obj->nr_maps; i++) {
1243 zfree(&obj->maps[i].name);
1244 if (obj->maps[i].clear_priv)
1245 obj->maps[i].clear_priv(&obj->maps[i],
1246 obj->maps[i].priv);
1247 obj->maps[i].priv = NULL;
1248 obj->maps[i].clear_priv = NULL;
1249 }
1250 zfree(&obj->maps);
1251 obj->nr_maps = 0;
1252
1253 if (obj->programs && obj->nr_programs) {
1254 for (i = 0; i < obj->nr_programs; i++)
1255 bpf_program__exit(&obj->programs[i]);
1256 }
1257 zfree(&obj->programs);
1258
1259 list_del(&obj->list);
1260 free(obj);
1261 }
1262
1263 struct bpf_object *
1264 bpf_object__next(struct bpf_object *prev)
1265 {
1266 struct bpf_object *next;
1267
1268 if (!prev)
1269 next = list_first_entry(&bpf_objects_list,
1270 struct bpf_object,
1271 list);
1272 else
1273 next = list_next_entry(prev, list);
1274
1275 /* Empty list is noticed here so don't need checking on entry. */
1276 if (&next->list == &bpf_objects_list)
1277 return NULL;
1278
1279 return next;
1280 }
1281
1282 const char *bpf_object__name(struct bpf_object *obj)
1283 {
1284 return obj ? obj->path : ERR_PTR(-EINVAL);
1285 }
1286
1287 unsigned int bpf_object__kversion(struct bpf_object *obj)
1288 {
1289 return obj ? obj->kern_version : 0;
1290 }
1291
1292 int bpf_object__set_priv(struct bpf_object *obj, void *priv,
1293 bpf_object_clear_priv_t clear_priv)
1294 {
1295 if (obj->priv && obj->clear_priv)
1296 obj->clear_priv(obj, obj->priv);
1297
1298 obj->priv = priv;
1299 obj->clear_priv = clear_priv;
1300 return 0;
1301 }
1302
1303 void *bpf_object__priv(struct bpf_object *obj)
1304 {
1305 return obj ? obj->priv : ERR_PTR(-EINVAL);
1306 }
1307
1308 struct bpf_program *
1309 bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
1310 {
1311 size_t idx;
1312
1313 if (!obj->programs)
1314 return NULL;
1315 /* First handler */
1316 if (prev == NULL)
1317 return &obj->programs[0];
1318
1319 if (prev->obj != obj) {
1320 pr_warning("error: program handler doesn't match object\n");
1321 return NULL;
1322 }
1323
1324 idx = (prev - obj->programs) + 1;
1325 if (idx >= obj->nr_programs)
1326 return NULL;
1327 return &obj->programs[idx];
1328 }
1329
1330 int bpf_program__set_priv(struct bpf_program *prog, void *priv,
1331 bpf_program_clear_priv_t clear_priv)
1332 {
1333 if (prog->priv && prog->clear_priv)
1334 prog->clear_priv(prog, prog->priv);
1335
1336 prog->priv = priv;
1337 prog->clear_priv = clear_priv;
1338 return 0;
1339 }
1340
1341 void *bpf_program__priv(struct bpf_program *prog)
1342 {
1343 return prog ? prog->priv : ERR_PTR(-EINVAL);
1344 }
1345
1346 const char *bpf_program__title(struct bpf_program *prog, bool needs_copy)
1347 {
1348 const char *title;
1349
1350 title = prog->section_name;
1351 if (needs_copy) {
1352 title = strdup(title);
1353 if (!title) {
1354 pr_warning("failed to strdup program title\n");
1355 return ERR_PTR(-ENOMEM);
1356 }
1357 }
1358
1359 return title;
1360 }
1361
1362 int bpf_program__fd(struct bpf_program *prog)
1363 {
1364 return bpf_program__nth_fd(prog, 0);
1365 }
1366
1367 int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
1368 bpf_program_prep_t prep)
1369 {
1370 int *instances_fds;
1371
1372 if (nr_instances <= 0 || !prep)
1373 return -EINVAL;
1374
1375 if (prog->instances.nr > 0 || prog->instances.fds) {
1376 pr_warning("Can't set pre-processor after loading\n");
1377 return -EINVAL;
1378 }
1379
1380 instances_fds = malloc(sizeof(int) * nr_instances);
1381 if (!instances_fds) {
1382 pr_warning("alloc memory failed for fds\n");
1383 return -ENOMEM;
1384 }
1385
1386 /* fill all fd with -1 */
1387 memset(instances_fds, -1, sizeof(int) * nr_instances);
1388
1389 prog->instances.nr = nr_instances;
1390 prog->instances.fds = instances_fds;
1391 prog->preprocessor = prep;
1392 return 0;
1393 }
1394
1395 int bpf_program__nth_fd(struct bpf_program *prog, int n)
1396 {
1397 int fd;
1398
1399 if (n >= prog->instances.nr || n < 0) {
1400 pr_warning("Can't get the %dth fd from program %s: only %d instances\n",
1401 n, prog->section_name, prog->instances.nr);
1402 return -EINVAL;
1403 }
1404
1405 fd = prog->instances.fds[n];
1406 if (fd < 0) {
1407 pr_warning("%dth instance of program '%s' is invalid\n",
1408 n, prog->section_name);
1409 return -ENOENT;
1410 }
1411
1412 return fd;
1413 }
1414
1415 static void bpf_program__set_type(struct bpf_program *prog,
1416 enum bpf_prog_type type)
1417 {
1418 prog->type = type;
1419 }
1420
1421 int bpf_program__set_tracepoint(struct bpf_program *prog)
1422 {
1423 if (!prog)
1424 return -EINVAL;
1425 bpf_program__set_type(prog, BPF_PROG_TYPE_TRACEPOINT);
1426 return 0;
1427 }
1428
1429 int bpf_program__set_kprobe(struct bpf_program *prog)
1430 {
1431 if (!prog)
1432 return -EINVAL;
1433 bpf_program__set_type(prog, BPF_PROG_TYPE_KPROBE);
1434 return 0;
1435 }
1436
1437 static bool bpf_program__is_type(struct bpf_program *prog,
1438 enum bpf_prog_type type)
1439 {
1440 return prog ? (prog->type == type) : false;
1441 }
1442
1443 bool bpf_program__is_tracepoint(struct bpf_program *prog)
1444 {
1445 return bpf_program__is_type(prog, BPF_PROG_TYPE_TRACEPOINT);
1446 }
1447
1448 bool bpf_program__is_kprobe(struct bpf_program *prog)
1449 {
1450 return bpf_program__is_type(prog, BPF_PROG_TYPE_KPROBE);
1451 }
1452
1453 int bpf_map__fd(struct bpf_map *map)
1454 {
1455 return map ? map->fd : -EINVAL;
1456 }
1457
1458 const struct bpf_map_def *bpf_map__def(struct bpf_map *map)
1459 {
1460 return map ? &map->def : ERR_PTR(-EINVAL);
1461 }
1462
1463 const char *bpf_map__name(struct bpf_map *map)
1464 {
1465 return map ? map->name : NULL;
1466 }
1467
1468 int bpf_map__set_priv(struct bpf_map *map, void *priv,
1469 bpf_map_clear_priv_t clear_priv)
1470 {
1471 if (!map)
1472 return -EINVAL;
1473
1474 if (map->priv) {
1475 if (map->clear_priv)
1476 map->clear_priv(map, map->priv);
1477 }
1478
1479 map->priv = priv;
1480 map->clear_priv = clear_priv;
1481 return 0;
1482 }
1483
1484 void *bpf_map__priv(struct bpf_map *map)
1485 {
1486 return map ? map->priv : ERR_PTR(-EINVAL);
1487 }
1488
1489 struct bpf_map *
1490 bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)
1491 {
1492 size_t idx;
1493 struct bpf_map *s, *e;
1494
1495 if (!obj || !obj->maps)
1496 return NULL;
1497
1498 s = obj->maps;
1499 e = obj->maps + obj->nr_maps;
1500
1501 if (prev == NULL)
1502 return s;
1503
1504 if ((prev < s) || (prev >= e)) {
1505 pr_warning("error in %s: map handler doesn't belong to object\n",
1506 __func__);
1507 return NULL;
1508 }
1509
1510 idx = (prev - obj->maps) + 1;
1511 if (idx >= obj->nr_maps)
1512 return NULL;
1513 return &obj->maps[idx];
1514 }
1515
1516 struct bpf_map *
1517 bpf_object__find_map_by_name(struct bpf_object *obj, const char *name)
1518 {
1519 struct bpf_map *pos;
1520
1521 bpf_map__for_each(pos, obj) {
1522 if (pos->name && !strcmp(pos->name, name))
1523 return pos;
1524 }
1525 return NULL;
1526 }
1527
1528 struct bpf_map *
1529 bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
1530 {
1531 int i;
1532
1533 for (i = 0; i < obj->nr_maps; i++) {
1534 if (obj->maps[i].offset == offset)
1535 return &obj->maps[i];
1536 }
1537 return ERR_PTR(-ENOENT);
1538 }
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