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  * 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 bool section_have_execinstr(struct bpf_object *obj, int idx)
 665 {
 666         Elf_Scn *scn;
 667         GElf_Shdr sh;
 668
 669         scn = elf_getscn(obj->efile.elf, idx);
 670         if (!scn)
 671                 return false;
 672
 673         if (gelf_getshdr(scn, &sh) != &sh)
 674                 return false;
 675
 676         if (sh.sh_flags & SHF_EXECINSTR)
 677                 return true;
 678
 679         return false;
 680 }
 681
 682 static int bpf_object__elf_collect(struct bpf_object *obj)
 683 {
 684         Elf *elf = obj->efile.elf;
 685         GElf_Ehdr *ep = &obj->efile.ehdr;
 686         Elf_Scn *scn = NULL;
 687         int idx = 0, err = 0;
 688
 689         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 690         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
 691                 pr_warning("failed to get e_shstrndx from %s\n",
 692                            obj->path);
 693                 return -LIBBPF_ERRNO__FORMAT;
 694         }
 695
 696         while ((scn = elf_nextscn(elf, scn)) != NULL) {
 697                 char *name;
 698                 GElf_Shdr sh;
 699                 Elf_Data *data;
 700
 701                 idx++;
 702                 if (gelf_getshdr(scn, &sh) != &sh) {
 703                         pr_warning("failed to get section header from %s\n",
 704                                    obj->path);
 705                         err = -LIBBPF_ERRNO__FORMAT;
 706                         goto out;
 707                 }
 708
 709                 name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
 710                 if (!name) {
 711                         pr_warning("failed to get section name from %s\n",
 712                                    obj->path);
 713                         err = -LIBBPF_ERRNO__FORMAT;
 714                         goto out;
 715                 }
 716
 717                 data = elf_getdata(scn, 0);
 718                 if (!data) {
 719                         pr_warning("failed to get section data from %s(%s)\n",
 720                                    name, obj->path);
 721                         err = -LIBBPF_ERRNO__FORMAT;
 722                         goto out;
 723                 }
 724                 pr_debug("section %s, size %ld, link %d, flags %lx, type=%d\n",
 725                          name, (unsigned long)data->d_size,
 726                          (int)sh.sh_link, (unsigned long)sh.sh_flags,
 727                          (int)sh.sh_type);
 728
 729                 if (strcmp(name, "license") == 0)
 730                         err = bpf_object__init_license(obj,
 731                                                        data->d_buf,
 732                                                        data->d_size);
 733                 else if (strcmp(name, "version") == 0)
 734                         err = bpf_object__init_kversion(obj,
 735                                                         data->d_buf,
 736                                                         data->d_size);
 737                 else if (strcmp(name, "maps") == 0)
 738                         obj->efile.maps_shndx = idx;
 739                 else if (sh.sh_type == SHT_SYMTAB) {
 740                         if (obj->efile.symbols) {
 741                                 pr_warning("bpf: multiple SYMTAB in %s\n",
 742                                            obj->path);
 743                                 err = -LIBBPF_ERRNO__FORMAT;
 744                         } else {
 745                                 obj->efile.symbols = data;
 746                                 obj->efile.strtabidx = sh.sh_link;
 747                         }
 748                 } else if ((sh.sh_type == SHT_PROGBITS) &&
 749                            (sh.sh_flags & SHF_EXECINSTR) &&
 750                            (data->d_size > 0)) {
 751                         err = bpf_object__add_program(obj, data->d_buf,
 752                                                       data->d_size, name, idx);
 753                         if (err) {
 754                                 char errmsg[STRERR_BUFSIZE];
 755
 756                                 strerror_r(-err, errmsg, sizeof(errmsg));
 757                                 pr_warning("failed to alloc program %s (%s): %s",
 758                                            name, obj->path, errmsg);
 759                         }
 760                 } else if (sh.sh_type == SHT_REL) {
 761                         void *reloc = obj->efile.reloc;
 762                         int nr_reloc = obj->efile.nr_reloc + 1;
 763                         int sec = sh.sh_info; /* points to other section */
 764
 765                         /* Only do relo for section with exec instructions */
 766                         if (!section_have_execinstr(obj, sec)) {
 767                                 pr_debug("skip relo %s(%d) for section(%d)\n",
 768                                          name, idx, sec);
 769                                 continue;
 770                         }
 771
 772                         reloc = realloc(reloc,
 773                                         sizeof(*obj->efile.reloc) * nr_reloc);
 774                         if (!reloc) {
 775                                 pr_warning("realloc failed\n");
 776                                 err = -ENOMEM;
 777                         } else {
 778                                 int n = nr_reloc - 1;
 779
 780                                 obj->efile.reloc = reloc;
 781                                 obj->efile.nr_reloc = nr_reloc;
 782
 783                                 obj->efile.reloc[n].shdr = sh;
 784                                 obj->efile.reloc[n].data = data;
 785                         }
 786                 }
 787                 if (err)
 788                         goto out;
 789         }
 790
 791         if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) {
 792                 pr_warning("Corrupted ELF file: index of strtab invalid\n");
 793                 return LIBBPF_ERRNO__FORMAT;
 794         }
 795         if (obj->efile.maps_shndx >= 0)
 796                 err = bpf_object__init_maps(obj);
 797 out:
 798         return err;
 799 }
 800
 801 static struct bpf_program *
 802 bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
 803 {
 804         struct bpf_program *prog;
 805         size_t i;
 806
 807         for (i = 0; i < obj->nr_programs; i++) {
 808                 prog = &obj->programs[i];
 809                 if (prog->idx == idx)
 810                         return prog;
 811         }
 812         return NULL;
 813 }
 814
 815 static int
 816 bpf_program__collect_reloc(struct bpf_program *prog,
 817                            size_t nr_maps, GElf_Shdr *shdr,
 818                            Elf_Data *data, Elf_Data *symbols,
 819                            int maps_shndx, struct bpf_map *maps)
 820 {
 821         int i, nrels;
 822
 823         pr_debug("collecting relocating info for: '%s'\n",
 824                  prog->section_name);
 825         nrels = shdr->sh_size / shdr->sh_entsize;
 826
 827         prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
 828         if (!prog->reloc_desc) {
 829                 pr_warning("failed to alloc memory in relocation\n");
 830                 return -ENOMEM;
 831         }
 832         prog->nr_reloc = nrels;
 833
 834         for (i = 0; i < nrels; i++) {
 835                 GElf_Sym sym;
 836                 GElf_Rel rel;
 837                 unsigned int insn_idx;
 838                 struct bpf_insn *insns = prog->insns;
 839                 size_t map_idx;
 840
 841                 if (!gelf_getrel(data, i, &rel)) {
 842                         pr_warning("relocation: failed to get %d reloc\n", i);
 843                         return -LIBBPF_ERRNO__FORMAT;
 844                 }
 845
 846                 if (!gelf_getsym(symbols,
 847                                  GELF_R_SYM(rel.r_info),
 848                                  &sym)) {
 849                         pr_warning("relocation: symbol %"PRIx64" not found\n",
 850                                    GELF_R_SYM(rel.r_info));
 851                         return -LIBBPF_ERRNO__FORMAT;
 852                 }
 853
 854                 if (sym.st_shndx != maps_shndx) {
 855                         pr_warning("Program '%s' contains non-map related relo data pointing to section %u\n",
 856                                    prog->section_name, sym.st_shndx);
 857                         return -LIBBPF_ERRNO__RELOC;
 858                 }
 859
 860                 insn_idx = rel.r_offset / sizeof(struct bpf_insn);
 861                 pr_debug("relocation: insn_idx=%u\n", insn_idx);
 862
 863                 if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
 864                         pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
 865                                    insn_idx, insns[insn_idx].code);
 866                         return -LIBBPF_ERRNO__RELOC;
 867                 }
 868
 869                 /* TODO: 'maps' is sorted. We can use bsearch to make it faster. */
 870                 for (map_idx = 0; map_idx < nr_maps; map_idx++) {
 871                         if (maps[map_idx].offset == sym.st_value) {
 872                                 pr_debug("relocation: find map %zd (%s) for insn %u\n",
 873                                          map_idx, maps[map_idx].name, insn_idx);
 874                                 break;
 875                         }
 876                 }
 877
 878                 if (map_idx >= nr_maps) {
 879                         pr_warning("bpf relocation: map_idx %d large than %d\n",
 880                                    (int)map_idx, (int)nr_maps - 1);
 881                         return -LIBBPF_ERRNO__RELOC;
 882                 }
 883
 884                 prog->reloc_desc[i].insn_idx = insn_idx;
 885                 prog->reloc_desc[i].map_idx = map_idx;
 886         }
 887         return 0;
 888 }
 889
 890 static int
 891 bpf_object__create_maps(struct bpf_object *obj)
 892 {
 893         unsigned int i;
 894
 895         for (i = 0; i < obj->nr_maps; i++) {
 896                 struct bpf_map_def *def = &obj->maps[i].def;
 897                 int *pfd = &obj->maps[i].fd;
 898
 899                 *pfd = bpf_create_map(def->type,
 900                                       def->key_size,
 901                                       def->value_size,
 902                                       def->max_entries,
 903                                       0);
 904                 if (*pfd < 0) {
 905                         size_t j;
 906                         int err = *pfd;
 907
 908                         pr_warning("failed to create map (name: '%s'): %s\n",
 909                                    obj->maps[i].name,
 910                                    strerror(errno));
 911                         for (j = 0; j < i; j++)
 912                                 zclose(obj->maps[j].fd);
 913                         return err;
 914                 }
 915                 pr_debug("create map %s: fd=%d\n", obj->maps[i].name, *pfd);
 916         }
 917
 918         return 0;
 919 }
 920
 921 static int
 922 bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
 923 {
 924         int i;
 925
 926         if (!prog || !prog->reloc_desc)
 927                 return 0;
 928
 929         for (i = 0; i < prog->nr_reloc; i++) {
 930                 int insn_idx, map_idx;
 931                 struct bpf_insn *insns = prog->insns;
 932
 933                 insn_idx = prog->reloc_desc[i].insn_idx;
 934                 map_idx = prog->reloc_desc[i].map_idx;
 935
 936                 if (insn_idx >= (int)prog->insns_cnt) {
 937                         pr_warning("relocation out of range: '%s'\n",
 938                                    prog->section_name);
 939                         return -LIBBPF_ERRNO__RELOC;
 940                 }
 941                 insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
 942                 insns[insn_idx].imm = obj->maps[map_idx].fd;
 943         }
 944
 945         zfree(&prog->reloc_desc);
 946         prog->nr_reloc = 0;
 947         return 0;
 948 }
 949
 950
 951 static int
 952 bpf_object__relocate(struct bpf_object *obj)
 953 {
 954         struct bpf_program *prog;
 955         size_t i;
 956         int err;
 957
 958         for (i = 0; i < obj->nr_programs; i++) {
 959                 prog = &obj->programs[i];
 960
 961                 err = bpf_program__relocate(prog, obj);
 962                 if (err) {
 963                         pr_warning("failed to relocate '%s'\n",
 964                                    prog->section_name);
 965                         return err;
 966                 }
 967         }
 968         return 0;
 969 }
 970
 971 static int bpf_object__collect_reloc(struct bpf_object *obj)
 972 {
 973         int i, err;
 974
 975         if (!obj_elf_valid(obj)) {
 976                 pr_warning("Internal error: elf object is closed\n");
 977                 return -LIBBPF_ERRNO__INTERNAL;
 978         }
 979
 980         for (i = 0; i < obj->efile.nr_reloc; i++) {
 981                 GElf_Shdr *shdr = &obj->efile.reloc[i].shdr;
 982                 Elf_Data *data = obj->efile.reloc[i].data;
 983                 int idx = shdr->sh_info;
 984                 struct bpf_program *prog;
 985                 size_t nr_maps = obj->nr_maps;
 986
 987                 if (shdr->sh_type != SHT_REL) {
 988                         pr_warning("internal error at %d\n", __LINE__);
 989                         return -LIBBPF_ERRNO__INTERNAL;
 990                 }
 991
 992                 prog = bpf_object__find_prog_by_idx(obj, idx);
 993                 if (!prog) {
 994                         pr_warning("relocation failed: no %d section\n",
 995                                    idx);
 996                         return -LIBBPF_ERRNO__RELOC;
 997                 }
 998
 999                 err = bpf_program__collect_reloc(prog, nr_maps,
1000                                                  shdr, data,
1001                                                  obj->efile.symbols,
1002                                                  obj->efile.maps_shndx,
1003                                                  obj->maps);
1004                 if (err)
1005                         return err;
1006         }
1007         return 0;
1008 }
1009
1010 static int
1011 load_program(enum bpf_prog_type type, struct bpf_insn *insns,
1012              int insns_cnt, char *license, u32 kern_version, int *pfd)
1013 {
1014         int ret;
1015         char *log_buf;
1016
1017         if (!insns || !insns_cnt)
1018                 return -EINVAL;
1019
1020         log_buf = malloc(BPF_LOG_BUF_SIZE);
1021         if (!log_buf)
1022                 pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
1023
1024         ret = bpf_load_program(type, insns, insns_cnt, license,
1025                                kern_version, log_buf, BPF_LOG_BUF_SIZE);
1026
1027         if (ret >= 0) {
1028                 *pfd = ret;
1029                 ret = 0;
1030                 goto out;
1031         }
1032
1033         ret = -LIBBPF_ERRNO__LOAD;
1034         pr_warning("load bpf program failed: %s\n", strerror(errno));
1035
1036         if (log_buf && log_buf[0] != '\0') {
1037                 ret = -LIBBPF_ERRNO__VERIFY;
1038                 pr_warning("-- BEGIN DUMP LOG ---\n");
1039                 pr_warning("\n%s\n", log_buf);
1040                 pr_warning("-- END LOG --\n");
1041         } else if (insns_cnt >= BPF_MAXINSNS) {
1042                 pr_warning("Program too large (%d insns), at most %d insns\n",
1043                            insns_cnt, BPF_MAXINSNS);
1044                 ret = -LIBBPF_ERRNO__PROG2BIG;
1045         } else {
1046                 /* Wrong program type? */
1047                 if (type != BPF_PROG_TYPE_KPROBE) {
1048                         int fd;
1049
1050                         fd = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,
1051                                               insns_cnt, license, kern_version,
1052                                               NULL, 0);
1053                         if (fd >= 0) {
1054                                 close(fd);
1055                                 ret = -LIBBPF_ERRNO__PROGTYPE;
1056                                 goto out;
1057                         }
1058                 }
1059
1060                 if (log_buf)
1061                         ret = -LIBBPF_ERRNO__KVER;
1062         }
1063
1064 out:
1065         free(log_buf);
1066         return ret;
1067 }
1068
1069 static int
1070 bpf_program__load(struct bpf_program *prog,
1071                   char *license, u32 kern_version)
1072 {
1073         int err = 0, fd, i;
1074
1075         if (prog->instances.nr < 0 || !prog->instances.fds) {
1076                 if (prog->preprocessor) {
1077                         pr_warning("Internal error: can't load program '%s'\n",
1078                                    prog->section_name);
1079                         return -LIBBPF_ERRNO__INTERNAL;
1080                 }
1081
1082                 prog->instances.fds = malloc(sizeof(int));
1083                 if (!prog->instances.fds) {
1084                         pr_warning("Not enough memory for BPF fds\n");
1085                         return -ENOMEM;
1086                 }
1087                 prog->instances.nr = 1;
1088                 prog->instances.fds[0] = -1;
1089         }
1090
1091         if (!prog->preprocessor) {
1092                 if (prog->instances.nr != 1) {
1093                         pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n",
1094                                    prog->section_name, prog->instances.nr);
1095                 }
1096                 err = load_program(prog->type, prog->insns, prog->insns_cnt,
1097                                    license, kern_version, &fd);
1098                 if (!err)
1099                         prog->instances.fds[0] = fd;
1100                 goto out;
1101         }
1102
1103         for (i = 0; i < prog->instances.nr; i++) {
1104                 struct bpf_prog_prep_result result;
1105                 bpf_program_prep_t preprocessor = prog->preprocessor;
1106
1107                 bzero(&result, sizeof(result));
1108                 err = preprocessor(prog, i, prog->insns,
1109                                    prog->insns_cnt, &result);
1110                 if (err) {
1111                         pr_warning("Preprocessing the %dth instance of program '%s' failed\n",
1112                                    i, prog->section_name);
1113                         goto out;
1114                 }
1115
1116                 if (!result.new_insn_ptr || !result.new_insn_cnt) {
1117                         pr_debug("Skip loading the %dth instance of program '%s'\n",
1118                                  i, prog->section_name);
1119                         prog->instances.fds[i] = -1;
1120                         if (result.pfd)
1121                                 *result.pfd = -1;
1122                         continue;
1123                 }
1124
1125                 err = load_program(prog->type, result.new_insn_ptr,
1126                                    result.new_insn_cnt,
1127                                    license, kern_version, &fd);
1128
1129                 if (err) {
1130                         pr_warning("Loading the %dth instance of program '%s' failed\n",
1131                                         i, prog->section_name);
1132                         goto out;
1133                 }
1134
1135                 if (result.pfd)
1136                         *result.pfd = fd;
1137                 prog->instances.fds[i] = fd;
1138         }
1139 out:
1140         if (err)
1141                 pr_warning("failed to load program '%s'\n",
1142                            prog->section_name);
1143         zfree(&prog->insns);
1144         prog->insns_cnt = 0;
1145         return err;
1146 }
1147
1148 static int
1149 bpf_object__load_progs(struct bpf_object *obj)
1150 {
1151         size_t i;
1152         int err;
1153
1154         for (i = 0; i < obj->nr_programs; i++) {
1155                 err = bpf_program__load(&obj->programs[i],
1156                                         obj->license,
1157                                         obj->kern_version);
1158                 if (err)
1159                         return err;
1160         }
1161         return 0;
1162 }
1163
1164 static int bpf_object__validate(struct bpf_object *obj)
1165 {
1166         if (obj->kern_version == 0) {
1167                 pr_warning("%s doesn't provide kernel version\n",
1168                            obj->path);
1169                 return -LIBBPF_ERRNO__KVERSION;
1170         }
1171         return 0;
1172 }
1173
1174 static struct bpf_object *
1175 __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz)
1176 {
1177         struct bpf_object *obj;
1178         int err;
1179
1180         if (elf_version(EV_CURRENT) == EV_NONE) {
1181                 pr_warning("failed to init libelf for %s\n", path);
1182                 return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
1183         }
1184
1185         obj = bpf_object__new(path, obj_buf, obj_buf_sz);
1186         if (IS_ERR(obj))
1187                 return obj;
1188
1189         CHECK_ERR(bpf_object__elf_init(obj), err, out);
1190         CHECK_ERR(bpf_object__check_endianness(obj), err, out);
1191         CHECK_ERR(bpf_object__elf_collect(obj), err, out);
1192         CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
1193         CHECK_ERR(bpf_object__validate(obj), err, out);
1194
1195         bpf_object__elf_finish(obj);
1196         return obj;
1197 out:
1198         bpf_object__close(obj);
1199         return ERR_PTR(err);
1200 }
1201
1202 struct bpf_object *bpf_object__open(const char *path)
1203 {
1204         /* param validation */
1205         if (!path)
1206                 return NULL;
1207
1208         pr_debug("loading %s\n", path);
1209
1210         return __bpf_object__open(path, NULL, 0);
1211 }
1212
1213 struct bpf_object *bpf_object__open_buffer(void *obj_buf,
1214                                            size_t obj_buf_sz,
1215                                            const char *name)
1216 {
1217         char tmp_name[64];
1218
1219         /* param validation */
1220         if (!obj_buf || obj_buf_sz <= 0)
1221                 return NULL;
1222
1223         if (!name) {
1224                 snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
1225                          (unsigned long)obj_buf,
1226                          (unsigned long)obj_buf_sz);
1227                 tmp_name[sizeof(tmp_name) - 1] = '\0';
1228                 name = tmp_name;
1229         }
1230         pr_debug("loading object '%s' from buffer\n",
1231                  name);
1232
1233         return __bpf_object__open(name, obj_buf, obj_buf_sz);
1234 }
1235
1236 int bpf_object__unload(struct bpf_object *obj)
1237 {
1238         size_t i;
1239
1240         if (!obj)
1241                 return -EINVAL;
1242
1243         for (i = 0; i < obj->nr_maps; i++)
1244                 zclose(obj->maps[i].fd);
1245
1246         for (i = 0; i < obj->nr_programs; i++)
1247                 bpf_program__unload(&obj->programs[i]);
1248
1249         return 0;
1250 }
1251
1252 int bpf_object__load(struct bpf_object *obj)
1253 {
1254         int err;
1255
1256         if (!obj)
1257                 return -EINVAL;
1258
1259         if (obj->loaded) {
1260                 pr_warning("object should not be loaded twice\n");
1261                 return -EINVAL;
1262         }
1263
1264         obj->loaded = true;
1265
1266         CHECK_ERR(bpf_object__create_maps(obj), err, out);
1267         CHECK_ERR(bpf_object__relocate(obj), err, out);
1268         CHECK_ERR(bpf_object__load_progs(obj), err, out);
1269
1270         return 0;
1271 out:
1272         bpf_object__unload(obj);
1273         pr_warning("failed to load object '%s'\n", obj->path);
1274         return err;
1275 }
1276
1277 static int check_path(const char *path)
1278 {
1279         struct statfs st_fs;
1280         char *dname, *dir;
1281         int err = 0;
1282
1283         if (path == NULL)
1284                 return -EINVAL;
1285
1286         dname = strdup(path);
1287         if (dname == NULL)
1288                 return -ENOMEM;
1289
1290         dir = dirname(dname);
1291         if (statfs(dir, &st_fs)) {
1292                 pr_warning("failed to statfs %s: %s\n", dir, strerror(errno));
1293                 err = -errno;
1294         }
1295         free(dname);
1296
1297         if (!err && st_fs.f_type != BPF_FS_MAGIC) {
1298                 pr_warning("specified path %s is not on BPF FS\n", path);
1299                 err = -EINVAL;
1300         }
1301
1302         return err;
1303 }
1304
1305 int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
1306                               int instance)
1307 {
1308         int err;
1309
1310         err = check_path(path);
1311         if (err)
1312                 return err;
1313
1314         if (prog == NULL) {
1315                 pr_warning("invalid program pointer\n");
1316                 return -EINVAL;
1317         }
1318
1319         if (instance < 0 || instance >= prog->instances.nr) {
1320                 pr_warning("invalid prog instance %d of prog %s (max %d)\n",
1321                            instance, prog->section_name, prog->instances.nr);
1322                 return -EINVAL;
1323         }
1324
1325         if (bpf_obj_pin(prog->instances.fds[instance], path)) {
1326                 pr_warning("failed to pin program: %s\n", strerror(errno));
1327                 return -errno;
1328         }
1329         pr_debug("pinned program '%s'\n", path);
1330
1331         return 0;
1332 }
1333
1334 static int make_dir(const char *path)
1335 {
1336         int err = 0;
1337
1338         if (mkdir(path, 0700) && errno != EEXIST)
1339                 err = -errno;
1340
1341         if (err)
1342                 pr_warning("failed to mkdir %s: %s\n", path, strerror(-err));
1343         return err;
1344 }
1345
1346 int bpf_program__pin(struct bpf_program *prog, const char *path)
1347 {
1348         int i, err;
1349
1350         err = check_path(path);
1351         if (err)
1352                 return err;
1353
1354         if (prog == NULL) {
1355                 pr_warning("invalid program pointer\n");
1356                 return -EINVAL;
1357         }
1358
1359         if (prog->instances.nr <= 0) {
1360                 pr_warning("no instances of prog %s to pin\n",
1361                            prog->section_name);
1362                 return -EINVAL;
1363         }
1364
1365         err = make_dir(path);
1366         if (err)
1367                 return err;
1368
1369         for (i = 0; i < prog->instances.nr; i++) {
1370                 char buf[PATH_MAX];
1371                 int len;
1372
1373                 len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
1374                 if (len < 0)
1375                         return -EINVAL;
1376                 else if (len >= PATH_MAX)
1377                         return -ENAMETOOLONG;
1378
1379                 err = bpf_program__pin_instance(prog, buf, i);
1380                 if (err)
1381                         return err;
1382         }
1383
1384         return 0;
1385 }
1386
1387 int bpf_map__pin(struct bpf_map *map, const char *path)
1388 {
1389         int err;
1390
1391         err = check_path(path);
1392         if (err)
1393                 return err;
1394
1395         if (map == NULL) {
1396                 pr_warning("invalid map pointer\n");
1397                 return -EINVAL;
1398         }
1399
1400         if (bpf_obj_pin(map->fd, path)) {
1401                 pr_warning("failed to pin map: %s\n", strerror(errno));
1402                 return -errno;
1403         }
1404
1405         pr_debug("pinned map '%s'\n", path);
1406         return 0;
1407 }
1408
1409 int bpf_object__pin(struct bpf_object *obj, const char *path)
1410 {
1411         struct bpf_program *prog;
1412         struct bpf_map *map;
1413         int err;
1414
1415         if (!obj)
1416                 return -ENOENT;
1417
1418         if (!obj->loaded) {
1419                 pr_warning("object not yet loaded; load it first\n");
1420                 return -ENOENT;
1421         }
1422
1423         err = make_dir(path);
1424         if (err)
1425                 return err;
1426
1427         bpf_map__for_each(map, obj) {
1428                 char buf[PATH_MAX];
1429                 int len;
1430
1431                 len = snprintf(buf, PATH_MAX, "%s/%s", path,
1432                                bpf_map__name(map));
1433                 if (len < 0)
1434                         return -EINVAL;
1435                 else if (len >= PATH_MAX)
1436                         return -ENAMETOOLONG;
1437
1438                 err = bpf_map__pin(map, buf);
1439                 if (err)
1440                         return err;
1441         }
1442
1443         bpf_object__for_each_program(prog, obj) {
1444                 char buf[PATH_MAX];
1445                 int len;
1446
1447                 len = snprintf(buf, PATH_MAX, "%s/%s", path,
1448                                prog->section_name);
1449                 if (len < 0)
1450                         return -EINVAL;
1451                 else if (len >= PATH_MAX)
1452                         return -ENAMETOOLONG;
1453
1454                 err = bpf_program__pin(prog, buf);
1455                 if (err)
1456                         return err;
1457         }
1458
1459         return 0;
1460 }
1461
1462 void bpf_object__close(struct bpf_object *obj)
1463 {
1464         size_t i;
1465
1466         if (!obj)
1467                 return;
1468
1469         if (obj->clear_priv)
1470                 obj->clear_priv(obj, obj->priv);
1471
1472         bpf_object__elf_finish(obj);
1473         bpf_object__unload(obj);
1474
1475         for (i = 0; i < obj->nr_maps; i++) {
1476                 zfree(&obj->maps[i].name);
1477                 if (obj->maps[i].clear_priv)
1478                         obj->maps[i].clear_priv(&obj->maps[i],
1479                                                 obj->maps[i].priv);
1480                 obj->maps[i].priv = NULL;
1481                 obj->maps[i].clear_priv = NULL;
1482         }
1483         zfree(&obj->maps);
1484         obj->nr_maps = 0;
1485
1486         if (obj->programs && obj->nr_programs) {
1487                 for (i = 0; i < obj->nr_programs; i++)
1488                         bpf_program__exit(&obj->programs[i]);
1489         }
1490         zfree(&obj->programs);
1491
1492         list_del(&obj->list);
1493         free(obj);
1494 }
1495
1496 struct bpf_object *
1497 bpf_object__next(struct bpf_object *prev)
1498 {
1499         struct bpf_object *next;
1500
1501         if (!prev)
1502                 next = list_first_entry(&bpf_objects_list,
1503                                         struct bpf_object,
1504                                         list);
1505         else
1506                 next = list_next_entry(prev, list);
1507
1508         /* Empty list is noticed here so don't need checking on entry. */
1509         if (&next->list == &bpf_objects_list)
1510                 return NULL;
1511
1512         return next;
1513 }
1514
1515 const char *bpf_object__name(struct bpf_object *obj)
1516 {
1517         return obj ? obj->path : ERR_PTR(-EINVAL);
1518 }
1519
1520 unsigned int bpf_object__kversion(struct bpf_object *obj)
1521 {
1522         return obj ? obj->kern_version : 0;
1523 }
1524
1525 int bpf_object__set_priv(struct bpf_object *obj, void *priv,
1526                          bpf_object_clear_priv_t clear_priv)
1527 {
1528         if (obj->priv && obj->clear_priv)
1529                 obj->clear_priv(obj, obj->priv);
1530
1531         obj->priv = priv;
1532         obj->clear_priv = clear_priv;
1533         return 0;
1534 }
1535
1536 void *bpf_object__priv(struct bpf_object *obj)
1537 {
1538         return obj ? obj->priv : ERR_PTR(-EINVAL);
1539 }
1540
1541 struct bpf_program *
1542 bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
1543 {
1544         size_t idx;
1545
1546         if (!obj->programs)
1547                 return NULL;
1548         /* First handler */
1549         if (prev == NULL)
1550                 return &obj->programs[0];
1551
1552         if (prev->obj != obj) {
1553                 pr_warning("error: program handler doesn't match object\n");
1554                 return NULL;
1555         }
1556
1557         idx = (prev - obj->programs) + 1;
1558         if (idx >= obj->nr_programs)
1559                 return NULL;
1560         return &obj->programs[idx];
1561 }
1562
1563 int bpf_program__set_priv(struct bpf_program *prog, void *priv,
1564                           bpf_program_clear_priv_t clear_priv)
1565 {
1566         if (prog->priv && prog->clear_priv)
1567                 prog->clear_priv(prog, prog->priv);
1568
1569         prog->priv = priv;
1570         prog->clear_priv = clear_priv;
1571         return 0;
1572 }
1573
1574 void *bpf_program__priv(struct bpf_program *prog)
1575 {
1576         return prog ? prog->priv : ERR_PTR(-EINVAL);
1577 }
1578
1579 const char *bpf_program__title(struct bpf_program *prog, bool needs_copy)
1580 {
1581         const char *title;
1582
1583         title = prog->section_name;
1584         if (needs_copy) {
1585                 title = strdup(title);
1586                 if (!title) {
1587                         pr_warning("failed to strdup program title\n");
1588                         return ERR_PTR(-ENOMEM);
1589                 }
1590         }
1591
1592         return title;
1593 }
1594
1595 int bpf_program__fd(struct bpf_program *prog)
1596 {
1597         return bpf_program__nth_fd(prog, 0);
1598 }
1599
1600 int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
1601                           bpf_program_prep_t prep)
1602 {
1603         int *instances_fds;
1604
1605         if (nr_instances <= 0 || !prep)
1606                 return -EINVAL;
1607
1608         if (prog->instances.nr > 0 || prog->instances.fds) {
1609                 pr_warning("Can't set pre-processor after loading\n");
1610                 return -EINVAL;
1611         }
1612
1613         instances_fds = malloc(sizeof(int) * nr_instances);
1614         if (!instances_fds) {
1615                 pr_warning("alloc memory failed for fds\n");
1616                 return -ENOMEM;
1617         }
1618
1619         /* fill all fd with -1 */
1620         memset(instances_fds, -1, sizeof(int) * nr_instances);
1621
1622         prog->instances.nr = nr_instances;
1623         prog->instances.fds = instances_fds;
1624         prog->preprocessor = prep;
1625         return 0;
1626 }
1627
1628 int bpf_program__nth_fd(struct bpf_program *prog, int n)
1629 {
1630         int fd;
1631
1632         if (n >= prog->instances.nr || n < 0) {
1633                 pr_warning("Can't get the %dth fd from program %s: only %d instances\n",
1634                            n, prog->section_name, prog->instances.nr);
1635                 return -EINVAL;
1636         }
1637
1638         fd = prog->instances.fds[n];
1639         if (fd < 0) {
1640                 pr_warning("%dth instance of program '%s' is invalid\n",
1641                            n, prog->section_name);
1642                 return -ENOENT;
1643         }
1644
1645         return fd;
1646 }
1647
1648 void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
1649 {
1650         prog->type = type;
1651 }
1652
1653 static bool bpf_program__is_type(struct bpf_program *prog,
1654                                  enum bpf_prog_type type)
1655 {
1656         return prog ? (prog->type == type) : false;
1657 }
1658
1659 #define BPF_PROG_TYPE_FNS(NAME, TYPE)                   \
1660 int bpf_program__set_##NAME(struct bpf_program *prog)   \
1661 {                                                       \
1662         if (!prog)                                      \
1663                 return -EINVAL;                         \
1664         bpf_program__set_type(prog, TYPE);              \
1665         return 0;                                       \
1666 }                                                       \
1667                                                         \
1668 bool bpf_program__is_##NAME(struct bpf_program *prog)   \
1669 {                                                       \
1670         return bpf_program__is_type(prog, TYPE);        \
1671 }                                                       \
1672
1673 BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
1674 BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
1675 BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
1676 BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
1677 BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
1678 BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
1679 BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
1680
1681 int bpf_map__fd(struct bpf_map *map)
1682 {
1683         return map ? map->fd : -EINVAL;
1684 }
1685
1686 const struct bpf_map_def *bpf_map__def(struct bpf_map *map)
1687 {
1688         return map ? &map->def : ERR_PTR(-EINVAL);
1689 }
1690
1691 const char *bpf_map__name(struct bpf_map *map)
1692 {
1693         return map ? map->name : NULL;
1694 }
1695
1696 int bpf_map__set_priv(struct bpf_map *map, void *priv,
1697                      bpf_map_clear_priv_t clear_priv)
1698 {
1699         if (!map)
1700                 return -EINVAL;
1701
1702         if (map->priv) {
1703                 if (map->clear_priv)
1704                         map->clear_priv(map, map->priv);
1705         }
1706
1707         map->priv = priv;
1708         map->clear_priv = clear_priv;
1709         return 0;
1710 }
1711
1712 void *bpf_map__priv(struct bpf_map *map)
1713 {
1714         return map ? map->priv : ERR_PTR(-EINVAL);
1715 }
1716
1717 struct bpf_map *
1718 bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)
1719 {
1720         size_t idx;
1721         struct bpf_map *s, *e;
1722
1723         if (!obj || !obj->maps)
1724                 return NULL;
1725
1726         s = obj->maps;
1727         e = obj->maps + obj->nr_maps;
1728
1729         if (prev == NULL)
1730                 return s;
1731
1732         if ((prev < s) || (prev >= e)) {
1733                 pr_warning("error in %s: map handler doesn't belong to object\n",
1734                            __func__);
1735                 return NULL;
1736         }
1737
1738         idx = (prev - obj->maps) + 1;
1739         if (idx >= obj->nr_maps)
1740                 return NULL;
1741         return &obj->maps[idx];
1742 }
1743
1744 struct bpf_map *
1745 bpf_object__find_map_by_name(struct bpf_object *obj, const char *name)
1746 {
1747         struct bpf_map *pos;
1748
1749         bpf_map__for_each(pos, obj) {
1750                 if (pos->name && !strcmp(pos->name, name))
1751                         return pos;
1752         }
1753         return NULL;
1754 }
1755
1756 struct bpf_map *
1757 bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
1758 {
1759         int i;
1760
1761         for (i = 0; i < obj->nr_maps; i++) {
1762                 if (obj->maps[i].offset == offset)
1763                         return &obj->maps[i];
1764         }
1765         return ERR_PTR(-ENOENT);
1766 }
1767
1768 long libbpf_get_error(const void *ptr)
1769 {
1770         if (IS_ERR(ptr))
1771                 return PTR_ERR(ptr);
1772         return 0;
1773 }
1774
1775 int bpf_prog_load(const char *file, enum bpf_prog_type type,
1776                   struct bpf_object **pobj, int *prog_fd)
1777 {
1778         struct bpf_program *prog;
1779         struct bpf_object *obj;
1780         int err;
1781
1782         obj = bpf_object__open(file);
1783         if (IS_ERR(obj))
1784                 return -ENOENT;
1785
1786         prog = bpf_program__next(NULL, obj);
1787         if (!prog) {
1788                 bpf_object__close(obj);
1789                 return -ENOENT;
1790         }
1791
1792         bpf_program__set_type(prog, type);
1793         err = bpf_object__load(obj);
1794         if (err) {
1795                 bpf_object__close(obj);
1796                 return -EINVAL;
1797         }
1798
1799         *pobj = obj;
1800         *prog_fd = bpf_program__fd(prog);
1801         return 0;
1802 }