tools/lib/bpf/libbpf.c

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