1 /* 2 * Common eBPF ELF object loading operations. 3 * 4 * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org> 5 * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com> 6 * Copyright (C) 2015 Huawei Inc. 7 */ 8 9 #include <stdlib.h> 10 #include <stdio.h> 11 #include <stdarg.h> 12 #include <inttypes.h> 13 #include <string.h> 14 #include <unistd.h> 15 #include <fcntl.h> 16 #include <errno.h> 17 #include <asm/unistd.h> 18 #include <linux/kernel.h> 19 #include <linux/bpf.h> 20 #include <linux/list.h> 21 #include <libelf.h> 22 #include <gelf.h> 23 24 #include "libbpf.h" 25 #include "bpf.h" 26 27 #define __printf(a, b) __attribute__((format(printf, a, b))) 28 29 __printf(1, 2) 30 static int __base_pr(const char *format, ...) 31 { 32 va_list args; 33 int err; 34 35 va_start(args, format); 36 err = vfprintf(stderr, format, args); 37 va_end(args); 38 return err; 39 } 40 41 static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr; 42 static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr; 43 static __printf(1, 2) libbpf_print_fn_t __pr_debug; 44 45 #define __pr(func, fmt, ...) \ 46 do { \ 47 if ((func)) \ 48 (func)("libbpf: " fmt, ##__VA_ARGS__); \ 49 } while (0) 50 51 #define pr_warning(fmt, ...) __pr(__pr_warning, fmt, ##__VA_ARGS__) 52 #define pr_info(fmt, ...) __pr(__pr_info, fmt, ##__VA_ARGS__) 53 #define pr_debug(fmt, ...) __pr(__pr_debug, fmt, ##__VA_ARGS__) 54 55 void libbpf_set_print(libbpf_print_fn_t warn, 56 libbpf_print_fn_t info, 57 libbpf_print_fn_t debug) 58 { 59 __pr_warning = warn; 60 __pr_info = info; 61 __pr_debug = debug; 62 } 63 64 /* Copied from tools/perf/util/util.h */ 65 #ifndef zfree 66 # define zfree(ptr) ({ free(*ptr); *ptr = NULL; }) 67 #endif 68 69 #ifndef zclose 70 # define zclose(fd) ({ \ 71 int ___err = 0; \ 72 if ((fd) >= 0) \ 73 ___err = close((fd)); \ 74 fd = -1; \ 75 ___err; }) 76 #endif 77 78 #ifdef HAVE_LIBELF_MMAP_SUPPORT 79 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP 80 #else 81 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ 82 #endif 83 84 /* 85 * bpf_prog should be a better name but it has been used in 86 * linux/filter.h. 87 */ 88 struct bpf_program { 89 /* Index in elf obj file, for relocation use. */ 90 int idx; 91 char *section_name; 92 struct bpf_insn *insns; 93 size_t insns_cnt; 94 95 struct { 96 int insn_idx; 97 int map_idx; 98 } *reloc_desc; 99 int nr_reloc; 100 101 int fd; 102 103 struct bpf_object *obj; 104 void *priv; 105 bpf_program_clear_priv_t clear_priv; 106 }; 107 108 static LIST_HEAD(bpf_objects_list); 109 110 struct bpf_object { 111 char license[64]; 112 u32 kern_version; 113 void *maps_buf; 114 size_t maps_buf_sz; 115 116 struct bpf_program *programs; 117 size_t nr_programs; 118 int *map_fds; 119 /* 120 * This field is required because maps_buf will be freed and 121 * maps_buf_sz will be set to 0 after loaded. 122 */ 123 size_t nr_map_fds; 124 bool loaded; 125 126 /* 127 * Information when doing elf related work. Only valid if fd 128 * is valid. 129 */ 130 struct { 131 int fd; 132 void *obj_buf; 133 size_t obj_buf_sz; 134 Elf *elf; 135 GElf_Ehdr ehdr; 136 Elf_Data *symbols; 137 struct { 138 GElf_Shdr shdr; 139 Elf_Data *data; 140 } *reloc; 141 int nr_reloc; 142 } efile; 143 /* 144 * All loaded bpf_object is linked in a list, which is 145 * hidden to caller. bpf_objects__<func> handlers deal with 146 * all objects. 147 */ 148 struct list_head list; 149 char path[]; 150 }; 151 #define obj_elf_valid(o) ((o)->efile.elf) 152 153 static void bpf_program__unload(struct bpf_program *prog) 154 { 155 if (!prog) 156 return; 157 158 zclose(prog->fd); 159 } 160 161 static void bpf_program__exit(struct bpf_program *prog) 162 { 163 if (!prog) 164 return; 165 166 if (prog->clear_priv) 167 prog->clear_priv(prog, prog->priv); 168 169 prog->priv = NULL; 170 prog->clear_priv = NULL; 171 172 bpf_program__unload(prog); 173 zfree(&prog->section_name); 174 zfree(&prog->insns); 175 zfree(&prog->reloc_desc); 176 177 prog->nr_reloc = 0; 178 prog->insns_cnt = 0; 179 prog->idx = -1; 180 } 181 182 static int 183 bpf_program__init(void *data, size_t size, char *name, int idx, 184 struct bpf_program *prog) 185 { 186 if (size < sizeof(struct bpf_insn)) { 187 pr_warning("corrupted section '%s'\n", name); 188 return -EINVAL; 189 } 190 191 bzero(prog, sizeof(*prog)); 192 193 prog->section_name = strdup(name); 194 if (!prog->section_name) { 195 pr_warning("failed to alloc name for prog %s\n", 196 name); 197 goto errout; 198 } 199 200 prog->insns = malloc(size); 201 if (!prog->insns) { 202 pr_warning("failed to alloc insns for %s\n", name); 203 goto errout; 204 } 205 prog->insns_cnt = size / sizeof(struct bpf_insn); 206 memcpy(prog->insns, data, 207 prog->insns_cnt * sizeof(struct bpf_insn)); 208 prog->idx = idx; 209 prog->fd = -1; 210 211 return 0; 212 errout: 213 bpf_program__exit(prog); 214 return -ENOMEM; 215 } 216 217 static int 218 bpf_object__add_program(struct bpf_object *obj, void *data, size_t size, 219 char *name, int idx) 220 { 221 struct bpf_program prog, *progs; 222 int nr_progs, err; 223 224 err = bpf_program__init(data, size, name, idx, &prog); 225 if (err) 226 return err; 227 228 progs = obj->programs; 229 nr_progs = obj->nr_programs; 230 231 progs = realloc(progs, sizeof(progs[0]) * (nr_progs + 1)); 232 if (!progs) { 233 /* 234 * In this case the original obj->programs 235 * is still valid, so don't need special treat for 236 * bpf_close_object(). 237 */ 238 pr_warning("failed to alloc a new program '%s'\n", 239 name); 240 bpf_program__exit(&prog); 241 return -ENOMEM; 242 } 243 244 pr_debug("found program %s\n", prog.section_name); 245 obj->programs = progs; 246 obj->nr_programs = nr_progs + 1; 247 prog.obj = obj; 248 progs[nr_progs] = prog; 249 return 0; 250 } 251 252 static struct bpf_object *bpf_object__new(const char *path, 253 void *obj_buf, 254 size_t obj_buf_sz) 255 { 256 struct bpf_object *obj; 257 258 obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1); 259 if (!obj) { 260 pr_warning("alloc memory failed for %s\n", path); 261 return NULL; 262 } 263 264 strcpy(obj->path, path); 265 obj->efile.fd = -1; 266 267 /* 268 * Caller of this function should also calls 269 * bpf_object__elf_finish() after data collection to return 270 * obj_buf to user. If not, we should duplicate the buffer to 271 * avoid user freeing them before elf finish. 272 */ 273 obj->efile.obj_buf = obj_buf; 274 obj->efile.obj_buf_sz = obj_buf_sz; 275 276 obj->loaded = false; 277 278 INIT_LIST_HEAD(&obj->list); 279 list_add(&obj->list, &bpf_objects_list); 280 return obj; 281 } 282 283 static void bpf_object__elf_finish(struct bpf_object *obj) 284 { 285 if (!obj_elf_valid(obj)) 286 return; 287 288 if (obj->efile.elf) { 289 elf_end(obj->efile.elf); 290 obj->efile.elf = NULL; 291 } 292 obj->efile.symbols = NULL; 293 294 zfree(&obj->efile.reloc); 295 obj->efile.nr_reloc = 0; 296 zclose(obj->efile.fd); 297 obj->efile.obj_buf = NULL; 298 obj->efile.obj_buf_sz = 0; 299 } 300 301 static int bpf_object__elf_init(struct bpf_object *obj) 302 { 303 int err = 0; 304 GElf_Ehdr *ep; 305 306 if (obj_elf_valid(obj)) { 307 pr_warning("elf init: internal error\n"); 308 return -EEXIST; 309 } 310 311 if (obj->efile.obj_buf_sz > 0) { 312 /* 313 * obj_buf should have been validated by 314 * bpf_object__open_buffer(). 315 */ 316 obj->efile.elf = elf_memory(obj->efile.obj_buf, 317 obj->efile.obj_buf_sz); 318 } else { 319 obj->efile.fd = open(obj->path, O_RDONLY); 320 if (obj->efile.fd < 0) { 321 pr_warning("failed to open %s: %s\n", obj->path, 322 strerror(errno)); 323 return -errno; 324 } 325 326 obj->efile.elf = elf_begin(obj->efile.fd, 327 LIBBPF_ELF_C_READ_MMAP, 328 NULL); 329 } 330 331 if (!obj->efile.elf) { 332 pr_warning("failed to open %s as ELF file\n", 333 obj->path); 334 err = -EINVAL; 335 goto errout; 336 } 337 338 if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) { 339 pr_warning("failed to get EHDR from %s\n", 340 obj->path); 341 err = -EINVAL; 342 goto errout; 343 } 344 ep = &obj->efile.ehdr; 345 346 if ((ep->e_type != ET_REL) || (ep->e_machine != 0)) { 347 pr_warning("%s is not an eBPF object file\n", 348 obj->path); 349 err = -EINVAL; 350 goto errout; 351 } 352 353 return 0; 354 errout: 355 bpf_object__elf_finish(obj); 356 return err; 357 } 358 359 static int 360 bpf_object__check_endianness(struct bpf_object *obj) 361 { 362 static unsigned int const endian = 1; 363 364 switch (obj->efile.ehdr.e_ident[EI_DATA]) { 365 case ELFDATA2LSB: 366 /* We are big endian, BPF obj is little endian. */ 367 if (*(unsigned char const *)&endian != 1) 368 goto mismatch; 369 break; 370 371 case ELFDATA2MSB: 372 /* We are little endian, BPF obj is big endian. */ 373 if (*(unsigned char const *)&endian != 0) 374 goto mismatch; 375 break; 376 default: 377 return -EINVAL; 378 } 379 380 return 0; 381 382 mismatch: 383 pr_warning("Error: endianness mismatch.\n"); 384 return -EINVAL; 385 } 386 387 static int 388 bpf_object__init_license(struct bpf_object *obj, 389 void *data, size_t size) 390 { 391 memcpy(obj->license, data, 392 min(size, sizeof(obj->license) - 1)); 393 pr_debug("license of %s is %s\n", obj->path, obj->license); 394 return 0; 395 } 396 397 static int 398 bpf_object__init_kversion(struct bpf_object *obj, 399 void *data, size_t size) 400 { 401 u32 kver; 402 403 if (size != sizeof(kver)) { 404 pr_warning("invalid kver section in %s\n", obj->path); 405 return -EINVAL; 406 } 407 memcpy(&kver, data, sizeof(kver)); 408 obj->kern_version = kver; 409 pr_debug("kernel version of %s is %x\n", obj->path, 410 obj->kern_version); 411 return 0; 412 } 413 414 static int 415 bpf_object__init_maps(struct bpf_object *obj, void *data, 416 size_t size) 417 { 418 if (size == 0) { 419 pr_debug("%s doesn't need map definition\n", 420 obj->path); 421 return 0; 422 } 423 424 obj->maps_buf = malloc(size); 425 if (!obj->maps_buf) { 426 pr_warning("malloc maps failed: %s\n", obj->path); 427 return -ENOMEM; 428 } 429 430 obj->maps_buf_sz = size; 431 memcpy(obj->maps_buf, data, size); 432 pr_debug("maps in %s: %ld bytes\n", obj->path, (long)size); 433 return 0; 434 } 435 436 static int bpf_object__elf_collect(struct bpf_object *obj) 437 { 438 Elf *elf = obj->efile.elf; 439 GElf_Ehdr *ep = &obj->efile.ehdr; 440 Elf_Scn *scn = NULL; 441 int idx = 0, err = 0; 442 443 /* Elf is corrupted/truncated, avoid calling elf_strptr. */ 444 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) { 445 pr_warning("failed to get e_shstrndx from %s\n", 446 obj->path); 447 return -EINVAL; 448 } 449 450 while ((scn = elf_nextscn(elf, scn)) != NULL) { 451 char *name; 452 GElf_Shdr sh; 453 Elf_Data *data; 454 455 idx++; 456 if (gelf_getshdr(scn, &sh) != &sh) { 457 pr_warning("failed to get section header from %s\n", 458 obj->path); 459 err = -EINVAL; 460 goto out; 461 } 462 463 name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name); 464 if (!name) { 465 pr_warning("failed to get section name from %s\n", 466 obj->path); 467 err = -EINVAL; 468 goto out; 469 } 470 471 data = elf_getdata(scn, 0); 472 if (!data) { 473 pr_warning("failed to get section data from %s(%s)\n", 474 name, obj->path); 475 err = -EINVAL; 476 goto out; 477 } 478 pr_debug("section %s, size %ld, link %d, flags %lx, type=%d\n", 479 name, (unsigned long)data->d_size, 480 (int)sh.sh_link, (unsigned long)sh.sh_flags, 481 (int)sh.sh_type); 482 483 if (strcmp(name, "license") == 0) 484 err = bpf_object__init_license(obj, 485 data->d_buf, 486 data->d_size); 487 else if (strcmp(name, "version") == 0) 488 err = bpf_object__init_kversion(obj, 489 data->d_buf, 490 data->d_size); 491 else if (strcmp(name, "maps") == 0) 492 err = bpf_object__init_maps(obj, data->d_buf, 493 data->d_size); 494 else if (sh.sh_type == SHT_SYMTAB) { 495 if (obj->efile.symbols) { 496 pr_warning("bpf: multiple SYMTAB in %s\n", 497 obj->path); 498 err = -EEXIST; 499 } else 500 obj->efile.symbols = data; 501 } else if ((sh.sh_type == SHT_PROGBITS) && 502 (sh.sh_flags & SHF_EXECINSTR) && 503 (data->d_size > 0)) { 504 err = bpf_object__add_program(obj, data->d_buf, 505 data->d_size, name, idx); 506 if (err) { 507 char errmsg[128]; 508 strerror_r(-err, errmsg, sizeof(errmsg)); 509 pr_warning("failed to alloc program %s (%s): %s", 510 name, obj->path, errmsg); 511 } 512 } else if (sh.sh_type == SHT_REL) { 513 void *reloc = obj->efile.reloc; 514 int nr_reloc = obj->efile.nr_reloc + 1; 515 516 reloc = realloc(reloc, 517 sizeof(*obj->efile.reloc) * nr_reloc); 518 if (!reloc) { 519 pr_warning("realloc failed\n"); 520 err = -ENOMEM; 521 } else { 522 int n = nr_reloc - 1; 523 524 obj->efile.reloc = reloc; 525 obj->efile.nr_reloc = nr_reloc; 526 527 obj->efile.reloc[n].shdr = sh; 528 obj->efile.reloc[n].data = data; 529 } 530 } 531 if (err) 532 goto out; 533 } 534 out: 535 return err; 536 } 537 538 static struct bpf_program * 539 bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx) 540 { 541 struct bpf_program *prog; 542 size_t i; 543 544 for (i = 0; i < obj->nr_programs; i++) { 545 prog = &obj->programs[i]; 546 if (prog->idx == idx) 547 return prog; 548 } 549 return NULL; 550 } 551 552 static int 553 bpf_program__collect_reloc(struct bpf_program *prog, 554 size_t nr_maps, GElf_Shdr *shdr, 555 Elf_Data *data, Elf_Data *symbols) 556 { 557 int i, nrels; 558 559 pr_debug("collecting relocating info for: '%s'\n", 560 prog->section_name); 561 nrels = shdr->sh_size / shdr->sh_entsize; 562 563 prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels); 564 if (!prog->reloc_desc) { 565 pr_warning("failed to alloc memory in relocation\n"); 566 return -ENOMEM; 567 } 568 prog->nr_reloc = nrels; 569 570 for (i = 0; i < nrels; i++) { 571 GElf_Sym sym; 572 GElf_Rel rel; 573 unsigned int insn_idx; 574 struct bpf_insn *insns = prog->insns; 575 size_t map_idx; 576 577 if (!gelf_getrel(data, i, &rel)) { 578 pr_warning("relocation: failed to get %d reloc\n", i); 579 return -EINVAL; 580 } 581 582 insn_idx = rel.r_offset / sizeof(struct bpf_insn); 583 pr_debug("relocation: insn_idx=%u\n", insn_idx); 584 585 if (!gelf_getsym(symbols, 586 GELF_R_SYM(rel.r_info), 587 &sym)) { 588 pr_warning("relocation: symbol %"PRIx64" not found\n", 589 GELF_R_SYM(rel.r_info)); 590 return -EINVAL; 591 } 592 593 if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) { 594 pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n", 595 insn_idx, insns[insn_idx].code); 596 return -EINVAL; 597 } 598 599 map_idx = sym.st_value / sizeof(struct bpf_map_def); 600 if (map_idx >= nr_maps) { 601 pr_warning("bpf relocation: map_idx %d large than %d\n", 602 (int)map_idx, (int)nr_maps - 1); 603 return -EINVAL; 604 } 605 606 prog->reloc_desc[i].insn_idx = insn_idx; 607 prog->reloc_desc[i].map_idx = map_idx; 608 } 609 return 0; 610 } 611 612 static int 613 bpf_object__create_maps(struct bpf_object *obj) 614 { 615 unsigned int i; 616 size_t nr_maps; 617 int *pfd; 618 619 nr_maps = obj->maps_buf_sz / sizeof(struct bpf_map_def); 620 if (!obj->maps_buf || !nr_maps) { 621 pr_debug("don't need create maps for %s\n", 622 obj->path); 623 return 0; 624 } 625 626 obj->map_fds = malloc(sizeof(int) * nr_maps); 627 if (!obj->map_fds) { 628 pr_warning("realloc perf_bpf_map_fds failed\n"); 629 return -ENOMEM; 630 } 631 obj->nr_map_fds = nr_maps; 632 633 /* fill all fd with -1 */ 634 memset(obj->map_fds, -1, sizeof(int) * nr_maps); 635 636 pfd = obj->map_fds; 637 for (i = 0; i < nr_maps; i++) { 638 struct bpf_map_def def; 639 640 def = *(struct bpf_map_def *)(obj->maps_buf + 641 i * sizeof(struct bpf_map_def)); 642 643 *pfd = bpf_create_map(def.type, 644 def.key_size, 645 def.value_size, 646 def.max_entries); 647 if (*pfd < 0) { 648 size_t j; 649 int err = *pfd; 650 651 pr_warning("failed to create map: %s\n", 652 strerror(errno)); 653 for (j = 0; j < i; j++) 654 zclose(obj->map_fds[j]); 655 obj->nr_map_fds = 0; 656 zfree(&obj->map_fds); 657 return err; 658 } 659 pr_debug("create map: fd=%d\n", *pfd); 660 pfd++; 661 } 662 663 zfree(&obj->maps_buf); 664 obj->maps_buf_sz = 0; 665 return 0; 666 } 667 668 static int 669 bpf_program__relocate(struct bpf_program *prog, int *map_fds) 670 { 671 int i; 672 673 if (!prog || !prog->reloc_desc) 674 return 0; 675 676 for (i = 0; i < prog->nr_reloc; i++) { 677 int insn_idx, map_idx; 678 struct bpf_insn *insns = prog->insns; 679 680 insn_idx = prog->reloc_desc[i].insn_idx; 681 map_idx = prog->reloc_desc[i].map_idx; 682 683 if (insn_idx >= (int)prog->insns_cnt) { 684 pr_warning("relocation out of range: '%s'\n", 685 prog->section_name); 686 return -ERANGE; 687 } 688 insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD; 689 insns[insn_idx].imm = map_fds[map_idx]; 690 } 691 692 zfree(&prog->reloc_desc); 693 prog->nr_reloc = 0; 694 return 0; 695 } 696 697 698 static int 699 bpf_object__relocate(struct bpf_object *obj) 700 { 701 struct bpf_program *prog; 702 size_t i; 703 int err; 704 705 for (i = 0; i < obj->nr_programs; i++) { 706 prog = &obj->programs[i]; 707 708 err = bpf_program__relocate(prog, obj->map_fds); 709 if (err) { 710 pr_warning("failed to relocate '%s'\n", 711 prog->section_name); 712 return err; 713 } 714 } 715 return 0; 716 } 717 718 static int bpf_object__collect_reloc(struct bpf_object *obj) 719 { 720 int i, err; 721 722 if (!obj_elf_valid(obj)) { 723 pr_warning("Internal error: elf object is closed\n"); 724 return -EINVAL; 725 } 726 727 for (i = 0; i < obj->efile.nr_reloc; i++) { 728 GElf_Shdr *shdr = &obj->efile.reloc[i].shdr; 729 Elf_Data *data = obj->efile.reloc[i].data; 730 int idx = shdr->sh_info; 731 struct bpf_program *prog; 732 size_t nr_maps = obj->maps_buf_sz / 733 sizeof(struct bpf_map_def); 734 735 if (shdr->sh_type != SHT_REL) { 736 pr_warning("internal error at %d\n", __LINE__); 737 return -EINVAL; 738 } 739 740 prog = bpf_object__find_prog_by_idx(obj, idx); 741 if (!prog) { 742 pr_warning("relocation failed: no %d section\n", 743 idx); 744 return -ENOENT; 745 } 746 747 err = bpf_program__collect_reloc(prog, nr_maps, 748 shdr, data, 749 obj->efile.symbols); 750 if (err) 751 return -EINVAL; 752 } 753 return 0; 754 } 755 756 static int 757 load_program(struct bpf_insn *insns, int insns_cnt, 758 char *license, u32 kern_version, int *pfd) 759 { 760 int ret; 761 char *log_buf; 762 763 if (!insns || !insns_cnt) 764 return -EINVAL; 765 766 log_buf = malloc(BPF_LOG_BUF_SIZE); 767 if (!log_buf) 768 pr_warning("Alloc log buffer for bpf loader error, continue without log\n"); 769 770 ret = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns, 771 insns_cnt, license, kern_version, 772 log_buf, BPF_LOG_BUF_SIZE); 773 774 if (ret >= 0) { 775 *pfd = ret; 776 ret = 0; 777 goto out; 778 } 779 780 ret = -EINVAL; 781 pr_warning("load bpf program failed: %s\n", strerror(errno)); 782 783 if (log_buf) { 784 pr_warning("-- BEGIN DUMP LOG ---\n"); 785 pr_warning("\n%s\n", log_buf); 786 pr_warning("-- END LOG --\n"); 787 } 788 789 out: 790 free(log_buf); 791 return ret; 792 } 793 794 static int 795 bpf_program__load(struct bpf_program *prog, 796 char *license, u32 kern_version) 797 { 798 int err, fd; 799 800 err = load_program(prog->insns, prog->insns_cnt, 801 license, kern_version, &fd); 802 if (!err) 803 prog->fd = fd; 804 805 if (err) 806 pr_warning("failed to load program '%s'\n", 807 prog->section_name); 808 zfree(&prog->insns); 809 prog->insns_cnt = 0; 810 return err; 811 } 812 813 static int 814 bpf_object__load_progs(struct bpf_object *obj) 815 { 816 size_t i; 817 int err; 818 819 for (i = 0; i < obj->nr_programs; i++) { 820 err = bpf_program__load(&obj->programs[i], 821 obj->license, 822 obj->kern_version); 823 if (err) 824 return err; 825 } 826 return 0; 827 } 828 829 static int bpf_object__validate(struct bpf_object *obj) 830 { 831 if (obj->kern_version == 0) { 832 pr_warning("%s doesn't provide kernel version\n", 833 obj->path); 834 return -EINVAL; 835 } 836 return 0; 837 } 838 839 static struct bpf_object * 840 __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz) 841 { 842 struct bpf_object *obj; 843 844 if (elf_version(EV_CURRENT) == EV_NONE) { 845 pr_warning("failed to init libelf for %s\n", path); 846 return NULL; 847 } 848 849 obj = bpf_object__new(path, obj_buf, obj_buf_sz); 850 if (!obj) 851 return NULL; 852 853 if (bpf_object__elf_init(obj)) 854 goto out; 855 if (bpf_object__check_endianness(obj)) 856 goto out; 857 if (bpf_object__elf_collect(obj)) 858 goto out; 859 if (bpf_object__collect_reloc(obj)) 860 goto out; 861 if (bpf_object__validate(obj)) 862 goto out; 863 864 bpf_object__elf_finish(obj); 865 return obj; 866 out: 867 bpf_object__close(obj); 868 return NULL; 869 } 870 871 struct bpf_object *bpf_object__open(const char *path) 872 { 873 /* param validation */ 874 if (!path) 875 return NULL; 876 877 pr_debug("loading %s\n", path); 878 879 return __bpf_object__open(path, NULL, 0); 880 } 881 882 struct bpf_object *bpf_object__open_buffer(void *obj_buf, 883 size_t obj_buf_sz, 884 const char *name) 885 { 886 char tmp_name[64]; 887 888 /* param validation */ 889 if (!obj_buf || obj_buf_sz <= 0) 890 return NULL; 891 892 if (!name) { 893 snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx", 894 (unsigned long)obj_buf, 895 (unsigned long)obj_buf_sz); 896 tmp_name[sizeof(tmp_name) - 1] = '\0'; 897 name = tmp_name; 898 } 899 pr_debug("loading object '%s' from buffer\n", 900 name); 901 902 return __bpf_object__open(name, obj_buf, obj_buf_sz); 903 } 904 905 int bpf_object__unload(struct bpf_object *obj) 906 { 907 size_t i; 908 909 if (!obj) 910 return -EINVAL; 911 912 for (i = 0; i < obj->nr_map_fds; i++) 913 zclose(obj->map_fds[i]); 914 zfree(&obj->map_fds); 915 obj->nr_map_fds = 0; 916 917 for (i = 0; i < obj->nr_programs; i++) 918 bpf_program__unload(&obj->programs[i]); 919 920 return 0; 921 } 922 923 int bpf_object__load(struct bpf_object *obj) 924 { 925 if (!obj) 926 return -EINVAL; 927 928 if (obj->loaded) { 929 pr_warning("object should not be loaded twice\n"); 930 return -EINVAL; 931 } 932 933 obj->loaded = true; 934 if (bpf_object__create_maps(obj)) 935 goto out; 936 if (bpf_object__relocate(obj)) 937 goto out; 938 if (bpf_object__load_progs(obj)) 939 goto out; 940 941 return 0; 942 out: 943 bpf_object__unload(obj); 944 pr_warning("failed to load object '%s'\n", obj->path); 945 return -EINVAL; 946 } 947 948 void bpf_object__close(struct bpf_object *obj) 949 { 950 size_t i; 951 952 if (!obj) 953 return; 954 955 bpf_object__elf_finish(obj); 956 bpf_object__unload(obj); 957 958 zfree(&obj->maps_buf); 959 960 if (obj->programs && obj->nr_programs) { 961 for (i = 0; i < obj->nr_programs; i++) 962 bpf_program__exit(&obj->programs[i]); 963 } 964 zfree(&obj->programs); 965 966 list_del(&obj->list); 967 free(obj); 968 } 969 970 struct bpf_object * 971 bpf_object__next(struct bpf_object *prev) 972 { 973 struct bpf_object *next; 974 975 if (!prev) 976 next = list_first_entry(&bpf_objects_list, 977 struct bpf_object, 978 list); 979 else 980 next = list_next_entry(prev, list); 981 982 /* Empty list is noticed here so don't need checking on entry. */ 983 if (&next->list == &bpf_objects_list) 984 return NULL; 985 986 return next; 987 } 988 989 const char * 990 bpf_object__get_name(struct bpf_object *obj) 991 { 992 if (!obj) 993 return NULL; 994 return obj->path; 995 } 996 997 struct bpf_program * 998 bpf_program__next(struct bpf_program *prev, struct bpf_object *obj) 999 { 1000 size_t idx; 1001 1002 if (!obj->programs) 1003 return NULL; 1004 /* First handler */ 1005 if (prev == NULL) 1006 return &obj->programs[0]; 1007 1008 if (prev->obj != obj) { 1009 pr_warning("error: program handler doesn't match object\n"); 1010 return NULL; 1011 } 1012 1013 idx = (prev - obj->programs) + 1; 1014 if (idx >= obj->nr_programs) 1015 return NULL; 1016 return &obj->programs[idx]; 1017 } 1018 1019 int bpf_program__set_private(struct bpf_program *prog, 1020 void *priv, 1021 bpf_program_clear_priv_t clear_priv) 1022 { 1023 if (prog->priv && prog->clear_priv) 1024 prog->clear_priv(prog, prog->priv); 1025 1026 prog->priv = priv; 1027 prog->clear_priv = clear_priv; 1028 return 0; 1029 } 1030 1031 int bpf_program__get_private(struct bpf_program *prog, void **ppriv) 1032 { 1033 *ppriv = prog->priv; 1034 return 0; 1035 } 1036 1037 const char *bpf_program__title(struct bpf_program *prog, bool dup) 1038 { 1039 const char *title; 1040 1041 title = prog->section_name; 1042 if (dup) { 1043 title = strdup(title); 1044 if (!title) { 1045 pr_warning("failed to strdup program title\n"); 1046 return NULL; 1047 } 1048 } 1049 1050 return title; 1051 } 1052 1053 int bpf_program__fd(struct bpf_program *prog) 1054 { 1055 return prog->fd; 1056 } 1057