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