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