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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / tools / lib / bpf / libbpf.c
blob5bbbf285af74a0afb01ae4dcaba9a7cdbb3a3e93
1 // SPDX-License-Identifier: LGPL-2.1
2
3 /*
4 * Common eBPF ELF object loading operations.
5 *
6 * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
7 * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
8 * Copyright (C) 2015 Huawei Inc.
9 * Copyright (C) 2017 Nicira, Inc.
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU Lesser General Public
13 * License as published by the Free Software Foundation;
14 * version 2.1 of the License (not later!)
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with this program; if not, see <http://www.gnu.org/licenses>
23 */
24
25 #include <stdlib.h>
26 #include <stdio.h>
27 #include <stdarg.h>
28 #include <libgen.h>
29 #include <inttypes.h>
30 #include <string.h>
31 #include <unistd.h>
32 #include <fcntl.h>
33 #include <errno.h>
34 #include <asm/unistd.h>
35 #include <linux/err.h>
36 #include <linux/kernel.h>
37 #include <linux/bpf.h>
38 #include <linux/list.h>
39 #include <linux/limits.h>
40 #include <sys/stat.h>
41 #include <sys/types.h>
42 #include <sys/vfs.h>
43 #include <libelf.h>
44 #include <gelf.h>
45
46 #include "libbpf.h"
47 #include "bpf.h"
48
49 #ifndef EM_BPF
50 #define EM_BPF 247
51 #endif
52
53 #ifndef BPF_FS_MAGIC
54 #define BPF_FS_MAGIC 0xcafe4a11
55 #endif
56
57 #define __printf(a, b) __attribute__((format(printf, a, b)))
58
59 __printf(1, 2)
60 static int __base_pr(const char *format, ...)
61 {
62 va_list args;
63 int err;
64
65 va_start(args, format);
66 err = vfprintf(stderr, format, args);
67 va_end(args);
68 return err;
69 }
70
71 static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr;
72 static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr;
73 static __printf(1, 2) libbpf_print_fn_t __pr_debug;
74
75 #define __pr(func, fmt, ...) \
76 do { \
77 if ((func)) \
78 (func)("libbpf: " fmt, ##__VA_ARGS__); \
79 } while (0)
80
81 #define pr_warning(fmt, ...) __pr(__pr_warning, fmt, ##__VA_ARGS__)
82 #define pr_info(fmt, ...) __pr(__pr_info, fmt, ##__VA_ARGS__)
83 #define pr_debug(fmt, ...) __pr(__pr_debug, fmt, ##__VA_ARGS__)
84
85 void libbpf_set_print(libbpf_print_fn_t warn,
86 libbpf_print_fn_t info,
87 libbpf_print_fn_t debug)
88 {
89 __pr_warning = warn;
90 __pr_info = info;
91 __pr_debug = debug;
92 }
93
94 #define STRERR_BUFSIZE 128
95
96 #define ERRNO_OFFSET(e) ((e) - __LIBBPF_ERRNO__START)
97 #define ERRCODE_OFFSET(c) ERRNO_OFFSET(LIBBPF_ERRNO__##c)
98 #define NR_ERRNO (__LIBBPF_ERRNO__END - __LIBBPF_ERRNO__START)
99
100 static const char *libbpf_strerror_table[NR_ERRNO] = {
101 [ERRCODE_OFFSET(LIBELF)] = "Something wrong in libelf",
102 [ERRCODE_OFFSET(FORMAT)] = "BPF object format invalid",
103 [ERRCODE_OFFSET(KVERSION)] = "'version' section incorrect or lost",
104 [ERRCODE_OFFSET(ENDIAN)] = "Endian mismatch",
105 [ERRCODE_OFFSET(INTERNAL)] = "Internal error in libbpf",
106 [ERRCODE_OFFSET(RELOC)] = "Relocation failed",
107 [ERRCODE_OFFSET(VERIFY)] = "Kernel verifier blocks program loading",
108 [ERRCODE_OFFSET(PROG2BIG)] = "Program too big",
109 [ERRCODE_OFFSET(KVER)] = "Incorrect kernel version",
110 [ERRCODE_OFFSET(PROGTYPE)] = "Kernel doesn't support this program type",
111 [ERRCODE_OFFSET(WRNGPID)] = "Wrong pid in netlink message",
112 [ERRCODE_OFFSET(INVSEQ)] = "Invalid netlink sequence",
113 };
114
115 int libbpf_strerror(int err, char *buf, size_t size)
116 {
117 if (!buf || !size)
118 return -1;
119
120 err = err > 0 ? err : -err;
121
122 if (err < __LIBBPF_ERRNO__START) {
123 int ret;
124
125 ret = strerror_r(err, buf, size);
126 buf[size - 1] = '\0';
127 return ret;
128 }
129
130 if (err < __LIBBPF_ERRNO__END) {
131 const char *msg;
132
133 msg = libbpf_strerror_table[ERRNO_OFFSET(err)];
134 snprintf(buf, size, "%s", msg);
135 buf[size - 1] = '\0';
136 return 0;
137 }
138
139 snprintf(buf, size, "Unknown libbpf error %d", err);
140 buf[size - 1] = '\0';
141 return -1;
142 }
143
144 #define CHECK_ERR(action, err, out) do { \
145 err = action; \
146 if (err) \
147 goto out; \
148 } while(0)
149
150
151 /* Copied from tools/perf/util/util.h */
152 #ifndef zfree
153 # define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
154 #endif
155
156 #ifndef zclose
157 # define zclose(fd) ({ \
158 int ___err = 0; \
159 if ((fd) >= 0) \
160 ___err = close((fd)); \
161 fd = -1; \
162 ___err; })
163 #endif
164
165 #ifdef HAVE_LIBELF_MMAP_SUPPORT
166 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
167 #else
168 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
169 #endif
170
171 /*
172 * bpf_prog should be a better name but it has been used in
173 * linux/filter.h.
174 */
175 struct bpf_program {
176 /* Index in elf obj file, for relocation use. */
177 int idx;
178 char *name;
179 char *section_name;
180 struct bpf_insn *insns;
181 size_t insns_cnt, main_prog_cnt;
182 enum bpf_prog_type type;
183
184 struct reloc_desc {
185 enum {
186 RELO_LD64,
187 RELO_CALL,
188 } type;
189 int insn_idx;
190 union {
191 int map_idx;
192 int text_off;
193 };
194 } *reloc_desc;
195 int nr_reloc;
196
197 struct {
198 int nr;
199 int *fds;
200 } instances;
201 bpf_program_prep_t preprocessor;
202
203 struct bpf_object *obj;
204 void *priv;
205 bpf_program_clear_priv_t clear_priv;
206 };
207
208 struct bpf_map {
209 int fd;
210 char *name;
211 size_t offset;
212 struct bpf_map_def def;
213 void *priv;
214 bpf_map_clear_priv_t clear_priv;
215 };
216
217 static LIST_HEAD(bpf_objects_list);
218
219 struct bpf_object {
220 char license[64];
221 u32 kern_version;
222
223 struct bpf_program *programs;
224 size_t nr_programs;
225 struct bpf_map *maps;
226 size_t nr_maps;
227
228 bool loaded;
229
230 /*
231 * Information when doing elf related work. Only valid if fd
232 * is valid.
233 */
234 struct {
235 int fd;
236 void *obj_buf;
237 size_t obj_buf_sz;
238 Elf *elf;
239 GElf_Ehdr ehdr;
240 Elf_Data *symbols;
241 size_t strtabidx;
242 struct {
243 GElf_Shdr shdr;
244 Elf_Data *data;
245 } *reloc;
246 int nr_reloc;
247 int maps_shndx;
248 int text_shndx;
249 } efile;
250 /*
251 * All loaded bpf_object is linked in a list, which is
252 * hidden to caller. bpf_objects__<func> handlers deal with
253 * all objects.
254 */
255 struct list_head list;
256
257 void *priv;
258 bpf_object_clear_priv_t clear_priv;
259
260 char path[];
261 };
262 #define obj_elf_valid(o) ((o)->efile.elf)
263
264 static void bpf_program__unload(struct bpf_program *prog)
265 {
266 int i;
267
268 if (!prog)
269 return;
270
271 /*
272 * If the object is opened but the program was never loaded,
273 * it is possible that prog->instances.nr == -1.
274 */
275 if (prog->instances.nr > 0) {
276 for (i = 0; i < prog->instances.nr; i++)
277 zclose(prog->instances.fds[i]);
278 } else if (prog->instances.nr != -1) {
279 pr_warning("Internal error: instances.nr is %d\n",
280 prog->instances.nr);
281 }
282
283 prog->instances.nr = -1;
284 zfree(&prog->instances.fds);
285 }
286
287 static void bpf_program__exit(struct bpf_program *prog)
288 {
289 if (!prog)
290 return;
291
292 if (prog->clear_priv)
293 prog->clear_priv(prog, prog->priv);
294
295 prog->priv = NULL;
296 prog->clear_priv = NULL;
297
298 bpf_program__unload(prog);
299 zfree(&prog->name);
300 zfree(&prog->section_name);
301 zfree(&prog->insns);
302 zfree(&prog->reloc_desc);
303
304 prog->nr_reloc = 0;
305 prog->insns_cnt = 0;
306 prog->idx = -1;
307 }
308
309 static int
310 bpf_program__init(void *data, size_t size, char *section_name, int idx,
311 struct bpf_program *prog)
312 {
313 if (size < sizeof(struct bpf_insn)) {
314 pr_warning("corrupted section '%s'\n", section_name);
315 return -EINVAL;
316 }
317
318 bzero(prog, sizeof(*prog));
319
320 prog->section_name = strdup(section_name);
321 if (!prog->section_name) {
322 pr_warning("failed to alloc name for prog under section(%d) %s\n",
323 idx, section_name);
324 goto errout;
325 }
326
327 prog->insns = malloc(size);
328 if (!prog->insns) {
329 pr_warning("failed to alloc insns for prog under section %s\n",
330 section_name);
331 goto errout;
332 }
333 prog->insns_cnt = size / sizeof(struct bpf_insn);
334 memcpy(prog->insns, data,
335 prog->insns_cnt * sizeof(struct bpf_insn));
336 prog->idx = idx;
337 prog->instances.fds = NULL;
338 prog->instances.nr = -1;
339 prog->type = BPF_PROG_TYPE_KPROBE;
340
341 return 0;
342 errout:
343 bpf_program__exit(prog);
344 return -ENOMEM;
345 }
346
347 static int
348 bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
349 char *section_name, int idx)
350 {
351 struct bpf_program prog, *progs;
352 int nr_progs, err;
353
354 err = bpf_program__init(data, size, section_name, idx, &prog);
355 if (err)
356 return err;
357
358 progs = obj->programs;
359 nr_progs = obj->nr_programs;
360
361 progs = realloc(progs, sizeof(progs[0]) * (nr_progs + 1));
362 if (!progs) {
363 /*
364 * In this case the original obj->programs
365 * is still valid, so don't need special treat for
366 * bpf_close_object().
367 */
368 pr_warning("failed to alloc a new program under section '%s'\n",
369 section_name);
370 bpf_program__exit(&prog);
371 return -ENOMEM;
372 }
373
374 pr_debug("found program %s\n", prog.section_name);
375 obj->programs = progs;
376 obj->nr_programs = nr_progs + 1;
377 prog.obj = obj;
378 progs[nr_progs] = prog;
379 return 0;
380 }
381
382 static int
383 bpf_object__init_prog_names(struct bpf_object *obj)
384 {
385 Elf_Data *symbols = obj->efile.symbols;
386 struct bpf_program *prog;
387 size_t pi, si;
388
389 for (pi = 0; pi < obj->nr_programs; pi++) {
390 const char *name = NULL;
391
392 prog = &obj->programs[pi];
393 if (prog->idx == obj->efile.text_shndx) {
394 name = ".text";
395 goto skip_search;
396 }
397
398 for (si = 0; si < symbols->d_size / sizeof(GElf_Sym) && !name;
399 si++) {
400 GElf_Sym sym;
401
402 if (!gelf_getsym(symbols, si, &sym))
403 continue;
404 if (sym.st_shndx != prog->idx)
405 continue;
406 if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL)
407 continue;
408
409 name = elf_strptr(obj->efile.elf,
410 obj->efile.strtabidx,
411 sym.st_name);
412 if (!name) {
413 pr_warning("failed to get sym name string for prog %s\n",
414 prog->section_name);
415 return -LIBBPF_ERRNO__LIBELF;
416 }
417 }
418
419 if (!name) {
420 pr_warning("failed to find sym for prog %s\n",
421 prog->section_name);
422 return -EINVAL;
423 }
424 skip_search:
425 prog->name = strdup(name);
426 if (!prog->name) {
427 pr_warning("failed to allocate memory for prog sym %s\n",
428 name);
429 return -ENOMEM;
430 }
431 }
432
433 return 0;
434 }
435
436 static struct bpf_object *bpf_object__new(const char *path,
437 void *obj_buf,
438 size_t obj_buf_sz)
439 {
440 struct bpf_object *obj;
441
442 obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
443 if (!obj) {
444 pr_warning("alloc memory failed for %s\n", path);
445 return ERR_PTR(-ENOMEM);
446 }
447
448 strcpy(obj->path, path);
449 obj->efile.fd = -1;
450
451 /*
452 * Caller of this function should also calls
453 * bpf_object__elf_finish() after data collection to return
454 * obj_buf to user. If not, we should duplicate the buffer to
455 * avoid user freeing them before elf finish.
456 */
457 obj->efile.obj_buf = obj_buf;
458 obj->efile.obj_buf_sz = obj_buf_sz;
459 obj->efile.maps_shndx = -1;
460
461 obj->loaded = false;
462
463 INIT_LIST_HEAD(&obj->list);
464 list_add(&obj->list, &bpf_objects_list);
465 return obj;
466 }
467
468 static void bpf_object__elf_finish(struct bpf_object *obj)
469 {
470 if (!obj_elf_valid(obj))
471 return;
472
473 if (obj->efile.elf) {
474 elf_end(obj->efile.elf);
475 obj->efile.elf = NULL;
476 }
477 obj->efile.symbols = NULL;
478
479 zfree(&obj->efile.reloc);
480 obj->efile.nr_reloc = 0;
481 zclose(obj->efile.fd);
482 obj->efile.obj_buf = NULL;
483 obj->efile.obj_buf_sz = 0;
484 }
485
486 static int bpf_object__elf_init(struct bpf_object *obj)
487 {
488 int err = 0;
489 GElf_Ehdr *ep;
490
491 if (obj_elf_valid(obj)) {
492 pr_warning("elf init: internal error\n");
493 return -LIBBPF_ERRNO__LIBELF;
494 }
495
496 if (obj->efile.obj_buf_sz > 0) {
497 /*
498 * obj_buf should have been validated by
499 * bpf_object__open_buffer().
500 */
501 obj->efile.elf = elf_memory(obj->efile.obj_buf,
502 obj->efile.obj_buf_sz);
503 } else {
504 obj->efile.fd = open(obj->path, O_RDONLY);
505 if (obj->efile.fd < 0) {
506 pr_warning("failed to open %s: %s\n", obj->path,
507 strerror(errno));
508 return -errno;
509 }
510
511 obj->efile.elf = elf_begin(obj->efile.fd,
512 LIBBPF_ELF_C_READ_MMAP,
513 NULL);
514 }
515
516 if (!obj->efile.elf) {
517 pr_warning("failed to open %s as ELF file\n",
518 obj->path);
519 err = -LIBBPF_ERRNO__LIBELF;
520 goto errout;
521 }
522
523 if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
524 pr_warning("failed to get EHDR from %s\n",
525 obj->path);
526 err = -LIBBPF_ERRNO__FORMAT;
527 goto errout;
528 }
529 ep = &obj->efile.ehdr;
530
531 /* Old LLVM set e_machine to EM_NONE */
532 if ((ep->e_type != ET_REL) || (ep->e_machine && (ep->e_machine != EM_BPF))) {
533 pr_warning("%s is not an eBPF object file\n",
534 obj->path);
535 err = -LIBBPF_ERRNO__FORMAT;
536 goto errout;
537 }
538
539 return 0;
540 errout:
541 bpf_object__elf_finish(obj);
542 return err;
543 }
544
545 static int
546 bpf_object__check_endianness(struct bpf_object *obj)
547 {
548 static unsigned int const endian = 1;
549
550 switch (obj->efile.ehdr.e_ident[EI_DATA]) {
551 case ELFDATA2LSB:
552 /* We are big endian, BPF obj is little endian. */
553 if (*(unsigned char const *)&endian != 1)
554 goto mismatch;
555 break;
556
557 case ELFDATA2MSB:
558 /* We are little endian, BPF obj is big endian. */
559 if (*(unsigned char const *)&endian != 0)
560 goto mismatch;
561 break;
562 default:
563 return -LIBBPF_ERRNO__ENDIAN;
564 }
565
566 return 0;
567
568 mismatch:
569 pr_warning("Error: endianness mismatch.\n");
570 return -LIBBPF_ERRNO__ENDIAN;
571 }
572
573 static int
574 bpf_object__init_license(struct bpf_object *obj,
575 void *data, size_t size)
576 {
577 memcpy(obj->license, data,
578 min(size, sizeof(obj->license) - 1));
579 pr_debug("license of %s is %s\n", obj->path, obj->license);
580 return 0;
581 }
582
583 static int
584 bpf_object__init_kversion(struct bpf_object *obj,
585 void *data, size_t size)
586 {
587 u32 kver;
588
589 if (size != sizeof(kver)) {
590 pr_warning("invalid kver section in %s\n", obj->path);
591 return -LIBBPF_ERRNO__FORMAT;
592 }
593 memcpy(&kver, data, sizeof(kver));
594 obj->kern_version = kver;
595 pr_debug("kernel version of %s is %x\n", obj->path,
596 obj->kern_version);
597 return 0;
598 }
599
600 static int compare_bpf_map(const void *_a, const void *_b)
601 {
602 const struct bpf_map *a = _a;
603 const struct bpf_map *b = _b;
604
605 return a->offset - b->offset;
606 }
607
608 static int
609 bpf_object__init_maps(struct bpf_object *obj)
610 {
611 int i, map_idx, map_def_sz, nr_maps = 0;
612 Elf_Scn *scn;
613 Elf_Data *data;
614 Elf_Data *symbols = obj->efile.symbols;
615
616 if (obj->efile.maps_shndx < 0)
617 return -EINVAL;
618 if (!symbols)
619 return -EINVAL;
620
621 scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx);
622 if (scn)
623 data = elf_getdata(scn, NULL);
624 if (!scn || !data) {
625 pr_warning("failed to get Elf_Data from map section %d\n",
626 obj->efile.maps_shndx);
627 return -EINVAL;
628 }
629
630 /*
631 * Count number of maps. Each map has a name.
632 * Array of maps is not supported: only the first element is
633 * considered.
634 *
635 * TODO: Detect array of map and report error.
636 */
637 for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
638 GElf_Sym sym;
639
640 if (!gelf_getsym(symbols, i, &sym))
641 continue;
642 if (sym.st_shndx != obj->efile.maps_shndx)
643 continue;
644 nr_maps++;
645 }
646
647 /* Alloc obj->maps and fill nr_maps. */
648 pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path,
649 nr_maps, data->d_size);
650
651 if (!nr_maps)
652 return 0;
653
654 /* Assume equally sized map definitions */
655 map_def_sz = data->d_size / nr_maps;
656 if (!data->d_size || (data->d_size % nr_maps) != 0) {
657 pr_warning("unable to determine map definition size "
658 "section %s, %d maps in %zd bytes\n",
659 obj->path, nr_maps, data->d_size);
660 return -EINVAL;
661 }
662
663 obj->maps = calloc(nr_maps, sizeof(obj->maps[0]));
664 if (!obj->maps) {
665 pr_warning("alloc maps for object failed\n");
666 return -ENOMEM;
667 }
668 obj->nr_maps = nr_maps;
669
670 /*
671 * fill all fd with -1 so won't close incorrect
672 * fd (fd=0 is stdin) when failure (zclose won't close
673 * negative fd)).
674 */
675 for (i = 0; i < nr_maps; i++)
676 obj->maps[i].fd = -1;
677
678 /*
679 * Fill obj->maps using data in "maps" section.
680 */
681 for (i = 0, map_idx = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
682 GElf_Sym sym;
683 const char *map_name;
684 struct bpf_map_def *def;
685
686 if (!gelf_getsym(symbols, i, &sym))
687 continue;
688 if (sym.st_shndx != obj->efile.maps_shndx)
689 continue;
690
691 map_name = elf_strptr(obj->efile.elf,
692 obj->efile.strtabidx,
693 sym.st_name);
694 obj->maps[map_idx].offset = sym.st_value;
695 if (sym.st_value + map_def_sz > data->d_size) {
696 pr_warning("corrupted maps section in %s: last map \"%s\" too small\n",
697 obj->path, map_name);
698 return -EINVAL;
699 }
700
701 obj->maps[map_idx].name = strdup(map_name);
702 if (!obj->maps[map_idx].name) {
703 pr_warning("failed to alloc map name\n");
704 return -ENOMEM;
705 }
706 pr_debug("map %d is \"%s\"\n", map_idx,
707 obj->maps[map_idx].name);
708 def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
709 /*
710 * If the definition of the map in the object file fits in
711 * bpf_map_def, copy it. Any extra fields in our version
712 * of bpf_map_def will default to zero as a result of the
713 * calloc above.
714 */
715 if (map_def_sz <= sizeof(struct bpf_map_def)) {
716 memcpy(&obj->maps[map_idx].def, def, map_def_sz);
717 } else {
718 /*
719 * Here the map structure being read is bigger than what
720 * we expect, truncate if the excess bits are all zero.
721 * If they are not zero, reject this map as
722 * incompatible.
723 */
724 char *b;
725 for (b = ((char *)def) + sizeof(struct bpf_map_def);
726 b < ((char *)def) + map_def_sz; b++) {
727 if (*b != 0) {
728 pr_warning("maps section in %s: \"%s\" "
729 "has unrecognized, non-zero "
730 "options\n",
731 obj->path, map_name);
732 return -EINVAL;
733 }
734 }
735 memcpy(&obj->maps[map_idx].def, def,
736 sizeof(struct bpf_map_def));
737 }
738 map_idx++;
739 }
740
741 qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]), compare_bpf_map);
742 return 0;
743 }
744
745 static bool section_have_execinstr(struct bpf_object *obj, int idx)
746 {
747 Elf_Scn *scn;
748 GElf_Shdr sh;
749
750 scn = elf_getscn(obj->efile.elf, idx);
751 if (!scn)
752 return false;
753
754 if (gelf_getshdr(scn, &sh) != &sh)
755 return false;
756
757 if (sh.sh_flags & SHF_EXECINSTR)
758 return true;
759
760 return false;
761 }
762
763 static int bpf_object__elf_collect(struct bpf_object *obj)
764 {
765 Elf *elf = obj->efile.elf;
766 GElf_Ehdr *ep = &obj->efile.ehdr;
767 Elf_Scn *scn = NULL;
768 int idx = 0, err = 0;
769
770 /* Elf is corrupted/truncated, avoid calling elf_strptr. */
771 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
772 pr_warning("failed to get e_shstrndx from %s\n",
773 obj->path);
774 return -LIBBPF_ERRNO__FORMAT;
775 }
776
777 while ((scn = elf_nextscn(elf, scn)) != NULL) {
778 char *name;
779 GElf_Shdr sh;
780 Elf_Data *data;
781
782 idx++;
783 if (gelf_getshdr(scn, &sh) != &sh) {
784 pr_warning("failed to get section(%d) header from %s\n",
785 idx, obj->path);
786 err = -LIBBPF_ERRNO__FORMAT;
787 goto out;
788 }
789
790 name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
791 if (!name) {
792 pr_warning("failed to get section(%d) name from %s\n",
793 idx, obj->path);
794 err = -LIBBPF_ERRNO__FORMAT;
795 goto out;
796 }
797
798 data = elf_getdata(scn, 0);
799 if (!data) {
800 pr_warning("failed to get section(%d) data from %s(%s)\n",
801 idx, name, obj->path);
802 err = -LIBBPF_ERRNO__FORMAT;
803 goto out;
804 }
805 pr_debug("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
806 idx, name, (unsigned long)data->d_size,
807 (int)sh.sh_link, (unsigned long)sh.sh_flags,
808 (int)sh.sh_type);
809
810 if (strcmp(name, "license") == 0)
811 err = bpf_object__init_license(obj,
812 data->d_buf,
813 data->d_size);
814 else if (strcmp(name, "version") == 0)
815 err = bpf_object__init_kversion(obj,
816 data->d_buf,
817 data->d_size);
818 else if (strcmp(name, "maps") == 0)
819 obj->efile.maps_shndx = idx;
820 else if (sh.sh_type == SHT_SYMTAB) {
821 if (obj->efile.symbols) {
822 pr_warning("bpf: multiple SYMTAB in %s\n",
823 obj->path);
824 err = -LIBBPF_ERRNO__FORMAT;
825 } else {
826 obj->efile.symbols = data;
827 obj->efile.strtabidx = sh.sh_link;
828 }
829 } else if ((sh.sh_type == SHT_PROGBITS) &&
830 (sh.sh_flags & SHF_EXECINSTR) &&
831 (data->d_size > 0)) {
832 if (strcmp(name, ".text") == 0)
833 obj->efile.text_shndx = idx;
834 err = bpf_object__add_program(obj, data->d_buf,
835 data->d_size, name, idx);
836 if (err) {
837 char errmsg[STRERR_BUFSIZE];
838
839 strerror_r(-err, errmsg, sizeof(errmsg));
840 pr_warning("failed to alloc program %s (%s): %s",
841 name, obj->path, errmsg);
842 }
843 } else if (sh.sh_type == SHT_REL) {
844 void *reloc = obj->efile.reloc;
845 int nr_reloc = obj->efile.nr_reloc + 1;
846 int sec = sh.sh_info; /* points to other section */
847
848 /* Only do relo for section with exec instructions */
849 if (!section_have_execinstr(obj, sec)) {
850 pr_debug("skip relo %s(%d) for section(%d)\n",
851 name, idx, sec);
852 continue;
853 }
854
855 reloc = realloc(reloc,
856 sizeof(*obj->efile.reloc) * nr_reloc);
857 if (!reloc) {
858 pr_warning("realloc failed\n");
859 err = -ENOMEM;
860 } else {
861 int n = nr_reloc - 1;
862
863 obj->efile.reloc = reloc;
864 obj->efile.nr_reloc = nr_reloc;
865
866 obj->efile.reloc[n].shdr = sh;
867 obj->efile.reloc[n].data = data;
868 }
869 } else {
870 pr_debug("skip section(%d) %s\n", idx, name);
871 }
872 if (err)
873 goto out;
874 }
875
876 if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) {
877 pr_warning("Corrupted ELF file: index of strtab invalid\n");
878 return LIBBPF_ERRNO__FORMAT;
879 }
880 if (obj->efile.maps_shndx >= 0) {
881 err = bpf_object__init_maps(obj);
882 if (err)
883 goto out;
884 }
885 err = bpf_object__init_prog_names(obj);
886 out:
887 return err;
888 }
889
890 static struct bpf_program *
891 bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
892 {
893 struct bpf_program *prog;
894 size_t i;
895
896 for (i = 0; i < obj->nr_programs; i++) {
897 prog = &obj->programs[i];
898 if (prog->idx == idx)
899 return prog;
900 }
901 return NULL;
902 }
903
904 static int
905 bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
906 Elf_Data *data, struct bpf_object *obj)
907 {
908 Elf_Data *symbols = obj->efile.symbols;
909 int text_shndx = obj->efile.text_shndx;
910 int maps_shndx = obj->efile.maps_shndx;
911 struct bpf_map *maps = obj->maps;
912 size_t nr_maps = obj->nr_maps;
913 int i, nrels;
914
915 pr_debug("collecting relocating info for: '%s'\n",
916 prog->section_name);
917 nrels = shdr->sh_size / shdr->sh_entsize;
918
919 prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
920 if (!prog->reloc_desc) {
921 pr_warning("failed to alloc memory in relocation\n");
922 return -ENOMEM;
923 }
924 prog->nr_reloc = nrels;
925
926 for (i = 0; i < nrels; i++) {
927 GElf_Sym sym;
928 GElf_Rel rel;
929 unsigned int insn_idx;
930 struct bpf_insn *insns = prog->insns;
931 size_t map_idx;
932
933 if (!gelf_getrel(data, i, &rel)) {
934 pr_warning("relocation: failed to get %d reloc\n", i);
935 return -LIBBPF_ERRNO__FORMAT;
936 }
937
938 if (!gelf_getsym(symbols,
939 GELF_R_SYM(rel.r_info),
940 &sym)) {
941 pr_warning("relocation: symbol %"PRIx64" not found\n",
942 GELF_R_SYM(rel.r_info));
943 return -LIBBPF_ERRNO__FORMAT;
944 }
945 pr_debug("relo for %lld value %lld name %d\n",
946 (long long) (rel.r_info >> 32),
947 (long long) sym.st_value, sym.st_name);
948
949 if (sym.st_shndx != maps_shndx && sym.st_shndx != text_shndx) {
950 pr_warning("Program '%s' contains non-map related relo data pointing to section %u\n",
951 prog->section_name, sym.st_shndx);
952 return -LIBBPF_ERRNO__RELOC;
953 }
954
955 insn_idx = rel.r_offset / sizeof(struct bpf_insn);
956 pr_debug("relocation: insn_idx=%u\n", insn_idx);
957
958 if (insns[insn_idx].code == (BPF_JMP | BPF_CALL)) {
959 if (insns[insn_idx].src_reg != BPF_PSEUDO_CALL) {
960 pr_warning("incorrect bpf_call opcode\n");
961 return -LIBBPF_ERRNO__RELOC;
962 }
963 prog->reloc_desc[i].type = RELO_CALL;
964 prog->reloc_desc[i].insn_idx = insn_idx;
965 prog->reloc_desc[i].text_off = sym.st_value;
966 continue;
967 }
968
969 if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
970 pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
971 insn_idx, insns[insn_idx].code);
972 return -LIBBPF_ERRNO__RELOC;
973 }
974
975 /* TODO: 'maps' is sorted. We can use bsearch to make it faster. */
976 for (map_idx = 0; map_idx < nr_maps; map_idx++) {
977 if (maps[map_idx].offset == sym.st_value) {
978 pr_debug("relocation: find map %zd (%s) for insn %u\n",
979 map_idx, maps[map_idx].name, insn_idx);
980 break;
981 }
982 }
983
984 if (map_idx >= nr_maps) {
985 pr_warning("bpf relocation: map_idx %d large than %d\n",
986 (int)map_idx, (int)nr_maps - 1);
987 return -LIBBPF_ERRNO__RELOC;
988 }
989
990 prog->reloc_desc[i].type = RELO_LD64;
991 prog->reloc_desc[i].insn_idx = insn_idx;
992 prog->reloc_desc[i].map_idx = map_idx;
993 }
994 return 0;
995 }
996
997 static int
998 bpf_object__create_maps(struct bpf_object *obj)
999 {
1000 unsigned int i;
1001
1002 for (i = 0; i < obj->nr_maps; i++) {
1003 struct bpf_map_def *def = &obj->maps[i].def;
1004 int *pfd = &obj->maps[i].fd;
1005
1006 *pfd = bpf_create_map_name(def->type,
1007 obj->maps[i].name,
1008 def->key_size,
1009 def->value_size,
1010 def->max_entries,
1011 def->map_flags);
1012 if (*pfd < 0) {
1013 size_t j;
1014 int err = *pfd;
1015
1016 pr_warning("failed to create map (name: '%s'): %s\n",
1017 obj->maps[i].name,
1018 strerror(errno));
1019 for (j = 0; j < i; j++)
1020 zclose(obj->maps[j].fd);
1021 return err;
1022 }
1023 pr_debug("create map %s: fd=%d\n", obj->maps[i].name, *pfd);
1024 }
1025
1026 return 0;
1027 }
1028
1029 static int
1030 bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj,
1031 struct reloc_desc *relo)
1032 {
1033 struct bpf_insn *insn, *new_insn;
1034 struct bpf_program *text;
1035 size_t new_cnt;
1036
1037 if (relo->type != RELO_CALL)
1038 return -LIBBPF_ERRNO__RELOC;
1039
1040 if (prog->idx == obj->efile.text_shndx) {
1041 pr_warning("relo in .text insn %d into off %d\n",
1042 relo->insn_idx, relo->text_off);
1043 return -LIBBPF_ERRNO__RELOC;
1044 }
1045
1046 if (prog->main_prog_cnt == 0) {
1047 text = bpf_object__find_prog_by_idx(obj, obj->efile.text_shndx);
1048 if (!text) {
1049 pr_warning("no .text section found yet relo into text exist\n");
1050 return -LIBBPF_ERRNO__RELOC;
1051 }
1052 new_cnt = prog->insns_cnt + text->insns_cnt;
1053 new_insn = realloc(prog->insns, new_cnt * sizeof(*insn));
1054 if (!new_insn) {
1055 pr_warning("oom in prog realloc\n");
1056 return -ENOMEM;
1057 }
1058 memcpy(new_insn + prog->insns_cnt, text->insns,
1059 text->insns_cnt * sizeof(*insn));
1060 prog->insns = new_insn;
1061 prog->main_prog_cnt = prog->insns_cnt;
1062 prog->insns_cnt = new_cnt;
1063 pr_debug("added %zd insn from %s to prog %s\n",
1064 text->insns_cnt, text->section_name,
1065 prog->section_name);
1066 }
1067 insn = &prog->insns[relo->insn_idx];
1068 insn->imm += prog->main_prog_cnt - relo->insn_idx;
1069 return 0;
1070 }
1071
1072 static int
1073 bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
1074 {
1075 int i, err;
1076
1077 if (!prog || !prog->reloc_desc)
1078 return 0;
1079
1080 for (i = 0; i < prog->nr_reloc; i++) {
1081 if (prog->reloc_desc[i].type == RELO_LD64) {
1082 struct bpf_insn *insns = prog->insns;
1083 int insn_idx, map_idx;
1084
1085 insn_idx = prog->reloc_desc[i].insn_idx;
1086 map_idx = prog->reloc_desc[i].map_idx;
1087
1088 if (insn_idx >= (int)prog->insns_cnt) {
1089 pr_warning("relocation out of range: '%s'\n",
1090 prog->section_name);
1091 return -LIBBPF_ERRNO__RELOC;
1092 }
1093 insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
1094 insns[insn_idx].imm = obj->maps[map_idx].fd;
1095 } else {
1096 err = bpf_program__reloc_text(prog, obj,
1097 &prog->reloc_desc[i]);
1098 if (err)
1099 return err;
1100 }
1101 }
1102
1103 zfree(&prog->reloc_desc);
1104 prog->nr_reloc = 0;
1105 return 0;
1106 }
1107
1108
1109 static int
1110 bpf_object__relocate(struct bpf_object *obj)
1111 {
1112 struct bpf_program *prog;
1113 size_t i;
1114 int err;
1115
1116 for (i = 0; i < obj->nr_programs; i++) {
1117 prog = &obj->programs[i];
1118
1119 err = bpf_program__relocate(prog, obj);
1120 if (err) {
1121 pr_warning("failed to relocate '%s'\n",
1122 prog->section_name);
1123 return err;
1124 }
1125 }
1126 return 0;
1127 }
1128
1129 static int bpf_object__collect_reloc(struct bpf_object *obj)
1130 {
1131 int i, err;
1132
1133 if (!obj_elf_valid(obj)) {
1134 pr_warning("Internal error: elf object is closed\n");
1135 return -LIBBPF_ERRNO__INTERNAL;
1136 }
1137
1138 for (i = 0; i < obj->efile.nr_reloc; i++) {
1139 GElf_Shdr *shdr = &obj->efile.reloc[i].shdr;
1140 Elf_Data *data = obj->efile.reloc[i].data;
1141 int idx = shdr->sh_info;
1142 struct bpf_program *prog;
1143
1144 if (shdr->sh_type != SHT_REL) {
1145 pr_warning("internal error at %d\n", __LINE__);
1146 return -LIBBPF_ERRNO__INTERNAL;
1147 }
1148
1149 prog = bpf_object__find_prog_by_idx(obj, idx);
1150 if (!prog) {
1151 pr_warning("relocation failed: no section(%d)\n", idx);
1152 return -LIBBPF_ERRNO__RELOC;
1153 }
1154
1155 err = bpf_program__collect_reloc(prog,
1156 shdr, data,
1157 obj);
1158 if (err)
1159 return err;
1160 }
1161 return 0;
1162 }
1163
1164 static int
1165 load_program(enum bpf_prog_type type, const char *name, struct bpf_insn *insns,
1166 int insns_cnt, char *license, u32 kern_version, int *pfd)
1167 {
1168 int ret;
1169 char *log_buf;
1170
1171 if (!insns || !insns_cnt)
1172 return -EINVAL;
1173
1174 log_buf = malloc(BPF_LOG_BUF_SIZE);
1175 if (!log_buf)
1176 pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
1177
1178 ret = bpf_load_program_name(type, name, insns, insns_cnt, license,
1179 kern_version, log_buf, BPF_LOG_BUF_SIZE);
1180
1181 if (ret >= 0) {
1182 *pfd = ret;
1183 ret = 0;
1184 goto out;
1185 }
1186
1187 ret = -LIBBPF_ERRNO__LOAD;
1188 pr_warning("load bpf program failed: %s\n", strerror(errno));
1189
1190 if (log_buf && log_buf[0] != '\0') {
1191 ret = -LIBBPF_ERRNO__VERIFY;
1192 pr_warning("-- BEGIN DUMP LOG ---\n");
1193 pr_warning("\n%s\n", log_buf);
1194 pr_warning("-- END LOG --\n");
1195 } else if (insns_cnt >= BPF_MAXINSNS) {
1196 pr_warning("Program too large (%d insns), at most %d insns\n",
1197 insns_cnt, BPF_MAXINSNS);
1198 ret = -LIBBPF_ERRNO__PROG2BIG;
1199 } else {
1200 /* Wrong program type? */
1201 if (type != BPF_PROG_TYPE_KPROBE) {
1202 int fd;
1203
1204 fd = bpf_load_program_name(BPF_PROG_TYPE_KPROBE, name,
1205 insns, insns_cnt, license,
1206 kern_version, NULL, 0);
1207 if (fd >= 0) {
1208 close(fd);
1209 ret = -LIBBPF_ERRNO__PROGTYPE;
1210 goto out;
1211 }
1212 }
1213
1214 if (log_buf)
1215 ret = -LIBBPF_ERRNO__KVER;
1216 }
1217
1218 out:
1219 free(log_buf);
1220 return ret;
1221 }
1222
1223 static int
1224 bpf_program__load(struct bpf_program *prog,
1225 char *license, u32 kern_version)
1226 {
1227 int err = 0, fd, i;
1228
1229 if (prog->instances.nr < 0 || !prog->instances.fds) {
1230 if (prog->preprocessor) {
1231 pr_warning("Internal error: can't load program '%s'\n",
1232 prog->section_name);
1233 return -LIBBPF_ERRNO__INTERNAL;
1234 }
1235
1236 prog->instances.fds = malloc(sizeof(int));
1237 if (!prog->instances.fds) {
1238 pr_warning("Not enough memory for BPF fds\n");
1239 return -ENOMEM;
1240 }
1241 prog->instances.nr = 1;
1242 prog->instances.fds[0] = -1;
1243 }
1244
1245 if (!prog->preprocessor) {
1246 if (prog->instances.nr != 1) {
1247 pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n",
1248 prog->section_name, prog->instances.nr);
1249 }
1250 err = load_program(prog->type, prog->name, prog->insns,
1251 prog->insns_cnt, license, kern_version, &fd);
1252 if (!err)
1253 prog->instances.fds[0] = fd;
1254 goto out;
1255 }
1256
1257 for (i = 0; i < prog->instances.nr; i++) {
1258 struct bpf_prog_prep_result result;
1259 bpf_program_prep_t preprocessor = prog->preprocessor;
1260
1261 bzero(&result, sizeof(result));
1262 err = preprocessor(prog, i, prog->insns,
1263 prog->insns_cnt, &result);
1264 if (err) {
1265 pr_warning("Preprocessing the %dth instance of program '%s' failed\n",
1266 i, prog->section_name);
1267 goto out;
1268 }
1269
1270 if (!result.new_insn_ptr || !result.new_insn_cnt) {
1271 pr_debug("Skip loading the %dth instance of program '%s'\n",
1272 i, prog->section_name);
1273 prog->instances.fds[i] = -1;
1274 if (result.pfd)
1275 *result.pfd = -1;
1276 continue;
1277 }
1278
1279 err = load_program(prog->type, prog->name,
1280 result.new_insn_ptr,
1281 result.new_insn_cnt,
1282 license, kern_version, &fd);
1283
1284 if (err) {
1285 pr_warning("Loading the %dth instance of program '%s' failed\n",
1286 i, prog->section_name);
1287 goto out;
1288 }
1289
1290 if (result.pfd)
1291 *result.pfd = fd;
1292 prog->instances.fds[i] = fd;
1293 }
1294 out:
1295 if (err)
1296 pr_warning("failed to load program '%s'\n",
1297 prog->section_name);
1298 zfree(&prog->insns);
1299 prog->insns_cnt = 0;
1300 return err;
1301 }
1302
1303 static int
1304 bpf_object__load_progs(struct bpf_object *obj)
1305 {
1306 size_t i;
1307 int err;
1308
1309 for (i = 0; i < obj->nr_programs; i++) {
1310 if (obj->programs[i].idx == obj->efile.text_shndx)
1311 continue;
1312 err = bpf_program__load(&obj->programs[i],
1313 obj->license,
1314 obj->kern_version);
1315 if (err)
1316 return err;
1317 }
1318 return 0;
1319 }
1320
1321 static int bpf_object__validate(struct bpf_object *obj)
1322 {
1323 if (obj->kern_version == 0) {
1324 pr_warning("%s doesn't provide kernel version\n",
1325 obj->path);
1326 return -LIBBPF_ERRNO__KVERSION;
1327 }
1328 return 0;
1329 }
1330
1331 static struct bpf_object *
1332 __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz)
1333 {
1334 struct bpf_object *obj;
1335 int err;
1336
1337 if (elf_version(EV_CURRENT) == EV_NONE) {
1338 pr_warning("failed to init libelf for %s\n", path);
1339 return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
1340 }
1341
1342 obj = bpf_object__new(path, obj_buf, obj_buf_sz);
1343 if (IS_ERR(obj))
1344 return obj;
1345
1346 CHECK_ERR(bpf_object__elf_init(obj), err, out);
1347 CHECK_ERR(bpf_object__check_endianness(obj), err, out);
1348 CHECK_ERR(bpf_object__elf_collect(obj), err, out);
1349 CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
1350 CHECK_ERR(bpf_object__validate(obj), err, out);
1351
1352 bpf_object__elf_finish(obj);
1353 return obj;
1354 out:
1355 bpf_object__close(obj);
1356 return ERR_PTR(err);
1357 }
1358
1359 struct bpf_object *bpf_object__open(const char *path)
1360 {
1361 /* param validation */
1362 if (!path)
1363 return NULL;
1364
1365 pr_debug("loading %s\n", path);
1366
1367 return __bpf_object__open(path, NULL, 0);
1368 }
1369
1370 struct bpf_object *bpf_object__open_buffer(void *obj_buf,
1371 size_t obj_buf_sz,
1372 const char *name)
1373 {
1374 char tmp_name[64];
1375
1376 /* param validation */
1377 if (!obj_buf || obj_buf_sz <= 0)
1378 return NULL;
1379
1380 if (!name) {
1381 snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
1382 (unsigned long)obj_buf,
1383 (unsigned long)obj_buf_sz);
1384 tmp_name[sizeof(tmp_name) - 1] = '\0';
1385 name = tmp_name;
1386 }
1387 pr_debug("loading object '%s' from buffer\n",
1388 name);
1389
1390 return __bpf_object__open(name, obj_buf, obj_buf_sz);
1391 }
1392
1393 int bpf_object__unload(struct bpf_object *obj)
1394 {
1395 size_t i;
1396
1397 if (!obj)
1398 return -EINVAL;
1399
1400 for (i = 0; i < obj->nr_maps; i++)
1401 zclose(obj->maps[i].fd);
1402
1403 for (i = 0; i < obj->nr_programs; i++)
1404 bpf_program__unload(&obj->programs[i]);
1405
1406 return 0;
1407 }
1408
1409 int bpf_object__load(struct bpf_object *obj)
1410 {
1411 int err;
1412
1413 if (!obj)
1414 return -EINVAL;
1415
1416 if (obj->loaded) {
1417 pr_warning("object should not be loaded twice\n");
1418 return -EINVAL;
1419 }
1420
1421 obj->loaded = true;
1422
1423 CHECK_ERR(bpf_object__create_maps(obj), err, out);
1424 CHECK_ERR(bpf_object__relocate(obj), err, out);
1425 CHECK_ERR(bpf_object__load_progs(obj), err, out);
1426
1427 return 0;
1428 out:
1429 bpf_object__unload(obj);
1430 pr_warning("failed to load object '%s'\n", obj->path);
1431 return err;
1432 }
1433
1434 static int check_path(const char *path)
1435 {
1436 struct statfs st_fs;
1437 char *dname, *dir;
1438 int err = 0;
1439
1440 if (path == NULL)
1441 return -EINVAL;
1442
1443 dname = strdup(path);
1444 if (dname == NULL)
1445 return -ENOMEM;
1446
1447 dir = dirname(dname);
1448 if (statfs(dir, &st_fs)) {
1449 pr_warning("failed to statfs %s: %s\n", dir, strerror(errno));
1450 err = -errno;
1451 }
1452 free(dname);
1453
1454 if (!err && st_fs.f_type != BPF_FS_MAGIC) {
1455 pr_warning("specified path %s is not on BPF FS\n", path);
1456 err = -EINVAL;
1457 }
1458
1459 return err;
1460 }
1461
1462 int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
1463 int instance)
1464 {
1465 int err;
1466
1467 err = check_path(path);
1468 if (err)
1469 return err;
1470
1471 if (prog == NULL) {
1472 pr_warning("invalid program pointer\n");
1473 return -EINVAL;
1474 }
1475
1476 if (instance < 0 || instance >= prog->instances.nr) {
1477 pr_warning("invalid prog instance %d of prog %s (max %d)\n",
1478 instance, prog->section_name, prog->instances.nr);
1479 return -EINVAL;
1480 }
1481
1482 if (bpf_obj_pin(prog->instances.fds[instance], path)) {
1483 pr_warning("failed to pin program: %s\n", strerror(errno));
1484 return -errno;
1485 }
1486 pr_debug("pinned program '%s'\n", path);
1487
1488 return 0;
1489 }
1490
1491 static int make_dir(const char *path)
1492 {
1493 int err = 0;
1494
1495 if (mkdir(path, 0700) && errno != EEXIST)
1496 err = -errno;
1497
1498 if (err)
1499 pr_warning("failed to mkdir %s: %s\n", path, strerror(-err));
1500 return err;
1501 }
1502
1503 int bpf_program__pin(struct bpf_program *prog, const char *path)
1504 {
1505 int i, err;
1506
1507 err = check_path(path);
1508 if (err)
1509 return err;
1510
1511 if (prog == NULL) {
1512 pr_warning("invalid program pointer\n");
1513 return -EINVAL;
1514 }
1515
1516 if (prog->instances.nr <= 0) {
1517 pr_warning("no instances of prog %s to pin\n",
1518 prog->section_name);
1519 return -EINVAL;
1520 }
1521
1522 err = make_dir(path);
1523 if (err)
1524 return err;
1525
1526 for (i = 0; i < prog->instances.nr; i++) {
1527 char buf[PATH_MAX];
1528 int len;
1529
1530 len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
1531 if (len < 0)
1532 return -EINVAL;
1533 else if (len >= PATH_MAX)
1534 return -ENAMETOOLONG;
1535
1536 err = bpf_program__pin_instance(prog, buf, i);
1537 if (err)
1538 return err;
1539 }
1540
1541 return 0;
1542 }
1543
1544 int bpf_map__pin(struct bpf_map *map, const char *path)
1545 {
1546 int err;
1547
1548 err = check_path(path);
1549 if (err)
1550 return err;
1551
1552 if (map == NULL) {
1553 pr_warning("invalid map pointer\n");
1554 return -EINVAL;
1555 }
1556
1557 if (bpf_obj_pin(map->fd, path)) {
1558 pr_warning("failed to pin map: %s\n", strerror(errno));
1559 return -errno;
1560 }
1561
1562 pr_debug("pinned map '%s'\n", path);
1563 return 0;
1564 }
1565
1566 int bpf_object__pin(struct bpf_object *obj, const char *path)
1567 {
1568 struct bpf_program *prog;
1569 struct bpf_map *map;
1570 int err;
1571
1572 if (!obj)
1573 return -ENOENT;
1574
1575 if (!obj->loaded) {
1576 pr_warning("object not yet loaded; load it first\n");
1577 return -ENOENT;
1578 }
1579
1580 err = make_dir(path);
1581 if (err)
1582 return err;
1583
1584 bpf_map__for_each(map, obj) {
1585 char buf[PATH_MAX];
1586 int len;
1587
1588 len = snprintf(buf, PATH_MAX, "%s/%s", path,
1589 bpf_map__name(map));
1590 if (len < 0)
1591 return -EINVAL;
1592 else if (len >= PATH_MAX)
1593 return -ENAMETOOLONG;
1594
1595 err = bpf_map__pin(map, buf);
1596 if (err)
1597 return err;
1598 }
1599
1600 bpf_object__for_each_program(prog, obj) {
1601 char buf[PATH_MAX];
1602 int len;
1603
1604 len = snprintf(buf, PATH_MAX, "%s/%s", path,
1605 prog->section_name);
1606 if (len < 0)
1607 return -EINVAL;
1608 else if (len >= PATH_MAX)
1609 return -ENAMETOOLONG;
1610
1611 err = bpf_program__pin(prog, buf);
1612 if (err)
1613 return err;
1614 }
1615
1616 return 0;
1617 }
1618
1619 void bpf_object__close(struct bpf_object *obj)
1620 {
1621 size_t i;
1622
1623 if (!obj)
1624 return;
1625
1626 if (obj->clear_priv)
1627 obj->clear_priv(obj, obj->priv);
1628
1629 bpf_object__elf_finish(obj);
1630 bpf_object__unload(obj);
1631
1632 for (i = 0; i < obj->nr_maps; i++) {
1633 zfree(&obj->maps[i].name);
1634 if (obj->maps[i].clear_priv)
1635 obj->maps[i].clear_priv(&obj->maps[i],
1636 obj->maps[i].priv);
1637 obj->maps[i].priv = NULL;
1638 obj->maps[i].clear_priv = NULL;
1639 }
1640 zfree(&obj->maps);
1641 obj->nr_maps = 0;
1642
1643 if (obj->programs && obj->nr_programs) {
1644 for (i = 0; i < obj->nr_programs; i++)
1645 bpf_program__exit(&obj->programs[i]);
1646 }
1647 zfree(&obj->programs);
1648
1649 list_del(&obj->list);
1650 free(obj);
1651 }
1652
1653 struct bpf_object *
1654 bpf_object__next(struct bpf_object *prev)
1655 {
1656 struct bpf_object *next;
1657
1658 if (!prev)
1659 next = list_first_entry(&bpf_objects_list,
1660 struct bpf_object,
1661 list);
1662 else
1663 next = list_next_entry(prev, list);
1664
1665 /* Empty list is noticed here so don't need checking on entry. */
1666 if (&next->list == &bpf_objects_list)
1667 return NULL;
1668
1669 return next;
1670 }
1671
1672 const char *bpf_object__name(struct bpf_object *obj)
1673 {
1674 return obj ? obj->path : ERR_PTR(-EINVAL);
1675 }
1676
1677 unsigned int bpf_object__kversion(struct bpf_object *obj)
1678 {
1679 return obj ? obj->kern_version : 0;
1680 }
1681
1682 int bpf_object__set_priv(struct bpf_object *obj, void *priv,
1683 bpf_object_clear_priv_t clear_priv)
1684 {
1685 if (obj->priv && obj->clear_priv)
1686 obj->clear_priv(obj, obj->priv);
1687
1688 obj->priv = priv;
1689 obj->clear_priv = clear_priv;
1690 return 0;
1691 }
1692
1693 void *bpf_object__priv(struct bpf_object *obj)
1694 {
1695 return obj ? obj->priv : ERR_PTR(-EINVAL);
1696 }
1697
1698 struct bpf_program *
1699 bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
1700 {
1701 size_t idx;
1702
1703 if (!obj->programs)
1704 return NULL;
1705 /* First handler */
1706 if (prev == NULL)
1707 return &obj->programs[0];
1708
1709 if (prev->obj != obj) {
1710 pr_warning("error: program handler doesn't match object\n");
1711 return NULL;
1712 }
1713
1714 idx = (prev - obj->programs) + 1;
1715 if (idx >= obj->nr_programs)
1716 return NULL;
1717 return &obj->programs[idx];
1718 }
1719
1720 int bpf_program__set_priv(struct bpf_program *prog, void *priv,
1721 bpf_program_clear_priv_t clear_priv)
1722 {
1723 if (prog->priv && prog->clear_priv)
1724 prog->clear_priv(prog, prog->priv);
1725
1726 prog->priv = priv;
1727 prog->clear_priv = clear_priv;
1728 return 0;
1729 }
1730
1731 void *bpf_program__priv(struct bpf_program *prog)
1732 {
1733 return prog ? prog->priv : ERR_PTR(-EINVAL);
1734 }
1735
1736 const char *bpf_program__title(struct bpf_program *prog, bool needs_copy)
1737 {
1738 const char *title;
1739
1740 title = prog->section_name;
1741 if (needs_copy) {
1742 title = strdup(title);
1743 if (!title) {
1744 pr_warning("failed to strdup program title\n");
1745 return ERR_PTR(-ENOMEM);
1746 }
1747 }
1748
1749 return title;
1750 }
1751
1752 int bpf_program__fd(struct bpf_program *prog)
1753 {
1754 return bpf_program__nth_fd(prog, 0);
1755 }
1756
1757 int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
1758 bpf_program_prep_t prep)
1759 {
1760 int *instances_fds;
1761
1762 if (nr_instances <= 0 || !prep)
1763 return -EINVAL;
1764
1765 if (prog->instances.nr > 0 || prog->instances.fds) {
1766 pr_warning("Can't set pre-processor after loading\n");
1767 return -EINVAL;
1768 }
1769
1770 instances_fds = malloc(sizeof(int) * nr_instances);
1771 if (!instances_fds) {
1772 pr_warning("alloc memory failed for fds\n");
1773 return -ENOMEM;
1774 }
1775
1776 /* fill all fd with -1 */
1777 memset(instances_fds, -1, sizeof(int) * nr_instances);
1778
1779 prog->instances.nr = nr_instances;
1780 prog->instances.fds = instances_fds;
1781 prog->preprocessor = prep;
1782 return 0;
1783 }
1784
1785 int bpf_program__nth_fd(struct bpf_program *prog, int n)
1786 {
1787 int fd;
1788
1789 if (n >= prog->instances.nr || n < 0) {
1790 pr_warning("Can't get the %dth fd from program %s: only %d instances\n",
1791 n, prog->section_name, prog->instances.nr);
1792 return -EINVAL;
1793 }
1794
1795 fd = prog->instances.fds[n];
1796 if (fd < 0) {
1797 pr_warning("%dth instance of program '%s' is invalid\n",
1798 n, prog->section_name);
1799 return -ENOENT;
1800 }
1801
1802 return fd;
1803 }
1804
1805 void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
1806 {
1807 prog->type = type;
1808 }
1809
1810 static bool bpf_program__is_type(struct bpf_program *prog,
1811 enum bpf_prog_type type)
1812 {
1813 return prog ? (prog->type == type) : false;
1814 }
1815
1816 #define BPF_PROG_TYPE_FNS(NAME, TYPE) \
1817 int bpf_program__set_##NAME(struct bpf_program *prog) \
1818 { \
1819 if (!prog) \
1820 return -EINVAL; \
1821 bpf_program__set_type(prog, TYPE); \
1822 return 0; \
1823 } \
1824 \
1825 bool bpf_program__is_##NAME(struct bpf_program *prog) \
1826 { \
1827 return bpf_program__is_type(prog, TYPE); \
1828 } \
1829
1830 BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
1831 BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
1832 BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
1833 BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
1834 BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
1835 BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
1836 BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
1837
1838 #define BPF_PROG_SEC(string, type) { string, sizeof(string) - 1, type }
1839 static const struct {
1840 const char *sec;
1841 size_t len;
1842 enum bpf_prog_type prog_type;
1843 } section_names[] = {
1844 BPF_PROG_SEC("socket", BPF_PROG_TYPE_SOCKET_FILTER),
1845 BPF_PROG_SEC("kprobe/", BPF_PROG_TYPE_KPROBE),
1846 BPF_PROG_SEC("kretprobe/", BPF_PROG_TYPE_KPROBE),
1847 BPF_PROG_SEC("classifier", BPF_PROG_TYPE_SCHED_CLS),
1848 BPF_PROG_SEC("action", BPF_PROG_TYPE_SCHED_ACT),
1849 BPF_PROG_SEC("tracepoint/", BPF_PROG_TYPE_TRACEPOINT),
1850 BPF_PROG_SEC("xdp", BPF_PROG_TYPE_XDP),
1851 BPF_PROG_SEC("perf_event", BPF_PROG_TYPE_PERF_EVENT),
1852 BPF_PROG_SEC("cgroup/skb", BPF_PROG_TYPE_CGROUP_SKB),
1853 BPF_PROG_SEC("cgroup/sock", BPF_PROG_TYPE_CGROUP_SOCK),
1854 BPF_PROG_SEC("cgroup/dev", BPF_PROG_TYPE_CGROUP_DEVICE),
1855 BPF_PROG_SEC("lwt_in", BPF_PROG_TYPE_LWT_IN),
1856 BPF_PROG_SEC("lwt_out", BPF_PROG_TYPE_LWT_OUT),
1857 BPF_PROG_SEC("lwt_xmit", BPF_PROG_TYPE_LWT_XMIT),
1858 BPF_PROG_SEC("sockops", BPF_PROG_TYPE_SOCK_OPS),
1859 BPF_PROG_SEC("sk_skb", BPF_PROG_TYPE_SK_SKB),
1860 };
1861 #undef BPF_PROG_SEC
1862
1863 static enum bpf_prog_type bpf_program__guess_type(struct bpf_program *prog)
1864 {
1865 int i;
1866
1867 if (!prog->section_name)
1868 goto err;
1869
1870 for (i = 0; i < ARRAY_SIZE(section_names); i++)
1871 if (strncmp(prog->section_name, section_names[i].sec,
1872 section_names[i].len) == 0)
1873 return section_names[i].prog_type;
1874
1875 err:
1876 pr_warning("failed to guess program type based on section name %s\n",
1877 prog->section_name);
1878
1879 return BPF_PROG_TYPE_UNSPEC;
1880 }
1881
1882 int bpf_map__fd(struct bpf_map *map)
1883 {
1884 return map ? map->fd : -EINVAL;
1885 }
1886
1887 const struct bpf_map_def *bpf_map__def(struct bpf_map *map)
1888 {
1889 return map ? &map->def : ERR_PTR(-EINVAL);
1890 }
1891
1892 const char *bpf_map__name(struct bpf_map *map)
1893 {
1894 return map ? map->name : NULL;
1895 }
1896
1897 int bpf_map__set_priv(struct bpf_map *map, void *priv,
1898 bpf_map_clear_priv_t clear_priv)
1899 {
1900 if (!map)
1901 return -EINVAL;
1902
1903 if (map->priv) {
1904 if (map->clear_priv)
1905 map->clear_priv(map, map->priv);
1906 }
1907
1908 map->priv = priv;
1909 map->clear_priv = clear_priv;
1910 return 0;
1911 }
1912
1913 void *bpf_map__priv(struct bpf_map *map)
1914 {
1915 return map ? map->priv : ERR_PTR(-EINVAL);
1916 }
1917
1918 struct bpf_map *
1919 bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)
1920 {
1921 size_t idx;
1922 struct bpf_map *s, *e;
1923
1924 if (!obj || !obj->maps)
1925 return NULL;
1926
1927 s = obj->maps;
1928 e = obj->maps + obj->nr_maps;
1929
1930 if (prev == NULL)
1931 return s;
1932
1933 if ((prev < s) || (prev >= e)) {
1934 pr_warning("error in %s: map handler doesn't belong to object\n",
1935 __func__);
1936 return NULL;
1937 }
1938
1939 idx = (prev - obj->maps) + 1;
1940 if (idx >= obj->nr_maps)
1941 return NULL;
1942 return &obj->maps[idx];
1943 }
1944
1945 struct bpf_map *
1946 bpf_object__find_map_by_name(struct bpf_object *obj, const char *name)
1947 {
1948 struct bpf_map *pos;
1949
1950 bpf_map__for_each(pos, obj) {
1951 if (pos->name && !strcmp(pos->name, name))
1952 return pos;
1953 }
1954 return NULL;
1955 }
1956
1957 struct bpf_map *
1958 bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
1959 {
1960 int i;
1961
1962 for (i = 0; i < obj->nr_maps; i++) {
1963 if (obj->maps[i].offset == offset)
1964 return &obj->maps[i];
1965 }
1966 return ERR_PTR(-ENOENT);
1967 }
1968
1969 long libbpf_get_error(const void *ptr)
1970 {
1971 if (IS_ERR(ptr))
1972 return PTR_ERR(ptr);
1973 return 0;
1974 }
1975
1976 int bpf_prog_load(const char *file, enum bpf_prog_type type,
1977 struct bpf_object **pobj, int *prog_fd)
1978 {
1979 struct bpf_program *prog, *first_prog = NULL;
1980 struct bpf_object *obj;
1981 int err;
1982
1983 obj = bpf_object__open(file);
1984 if (IS_ERR(obj))
1985 return -ENOENT;
1986
1987 bpf_object__for_each_program(prog, obj) {
1988 /*
1989 * If type is not specified, try to guess it based on
1990 * section name.
1991 */
1992 if (type == BPF_PROG_TYPE_UNSPEC) {
1993 type = bpf_program__guess_type(prog);
1994 if (type == BPF_PROG_TYPE_UNSPEC) {
1995 bpf_object__close(obj);
1996 return -EINVAL;
1997 }
1998 }
1999
2000 bpf_program__set_type(prog, type);
2001 if (prog->idx != obj->efile.text_shndx && !first_prog)
2002 first_prog = prog;
2003 }
2004
2005 if (!first_prog) {
2006 pr_warning("object file doesn't contain bpf program\n");
2007 bpf_object__close(obj);
2008 return -ENOENT;
2009 }
2010
2011 err = bpf_object__load(obj);
2012 if (err) {
2013 bpf_object__close(obj);
2014 return -EINVAL;
2015 }
2016
2017 *pobj = obj;
2018 *prog_fd = bpf_program__fd(first_prog);
2019 return 0;
2020 }
CRIS linux kernel tree