tools/perf/util/build-id.c

   1 /*
   2  * build-id.c
   3  *
   4  * build-id support
   5  *
   6  * Copyright (C) 2009, 2010 Red Hat Inc.
   7  * Copyright (C) 2009, 2010 Arnaldo Carvalho de Melo <acme@redhat.com>
   8  */
   9 #include "util.h"
  10 #include <stdio.h>
  11 #include "build-id.h"
  12 #include "event.h"
  13 #include "symbol.h"
  14 #include <linux/kernel.h>
  15 #include "debug.h"
  16 #include "session.h"
  17 #include "tool.h"
  18 #include "header.h"
  19 #include "vdso.h"
  20 #include "probe-file.h"
  21
  22
  23 static bool no_buildid_cache;
  24
  25 int build_id__mark_dso_hit(struct perf_tool *tool __maybe_unused,
  26                            union perf_event *event,
  27                            struct perf_sample *sample,
  28                            struct perf_evsel *evsel __maybe_unused,
  29                            struct machine *machine)
  30 {
  31         struct addr_location al;
  32         struct thread *thread = machine__findnew_thread(machine, sample->pid,
  33                                                         sample->tid);
  34
  35         if (thread == NULL) {
  36                 pr_err("problem processing %d event, skipping it.\n",
  37                         event->header.type);
  38                 return -1;
  39         }
  40
  41         thread__find_addr_map(thread, sample->cpumode, MAP__FUNCTION, sample->ip, &al);
  42
  43         if (al.map != NULL)
  44                 al.map->dso->hit = 1;
  45
  46         thread__put(thread);
  47         return 0;
  48 }
  49
  50 static int perf_event__exit_del_thread(struct perf_tool *tool __maybe_unused,
  51                                        union perf_event *event,
  52                                        struct perf_sample *sample
  53                                        __maybe_unused,
  54                                        struct machine *machine)
  55 {
  56         struct thread *thread = machine__findnew_thread(machine,
  57                                                         event->fork.pid,
  58                                                         event->fork.tid);
  59
  60         dump_printf("(%d:%d):(%d:%d)\n", event->fork.pid, event->fork.tid,
  61                     event->fork.ppid, event->fork.ptid);
  62
  63         if (thread) {
  64                 machine__remove_thread(machine, thread);
  65                 thread__put(thread);
  66         }
  67
  68         return 0;
  69 }
  70
  71 struct perf_tool build_id__mark_dso_hit_ops = {
  72         .sample = build_id__mark_dso_hit,
  73         .mmap   = perf_event__process_mmap,
  74         .mmap2  = perf_event__process_mmap2,
  75         .fork   = perf_event__process_fork,
  76         .exit   = perf_event__exit_del_thread,
  77         .attr            = perf_event__process_attr,
  78         .build_id        = perf_event__process_build_id,
  79         .ordered_events  = true,
  80 };
  81
  82 int build_id__sprintf(const u8 *build_id, int len, char *bf)
  83 {
  84         char *bid = bf;
  85         const u8 *raw = build_id;
  86         int i;
  87
  88         for (i = 0; i < len; ++i) {
  89                 sprintf(bid, "%02x", *raw);
  90                 ++raw;
  91                 bid += 2;
  92         }
  93
  94         return (bid - bf) + 1;
  95 }
  96
  97 int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id)
  98 {
  99         char notes[PATH_MAX];
 100         u8 build_id[BUILD_ID_SIZE];
 101         int ret;
 102
 103         if (!root_dir)
 104                 root_dir = "";
 105
 106         scnprintf(notes, sizeof(notes), "%s/sys/kernel/notes", root_dir);
 107
 108         ret = sysfs__read_build_id(notes, build_id, sizeof(build_id));
 109         if (ret < 0)
 110                 return ret;
 111
 112         return build_id__sprintf(build_id, sizeof(build_id), sbuild_id);
 113 }
 114
 115 int filename__sprintf_build_id(const char *pathname, char *sbuild_id)
 116 {
 117         u8 build_id[BUILD_ID_SIZE];
 118         int ret;
 119
 120         ret = filename__read_build_id(pathname, build_id, sizeof(build_id));
 121         if (ret < 0)
 122                 return ret;
 123         else if (ret != sizeof(build_id))
 124                 return -EINVAL;
 125
 126         return build_id__sprintf(build_id, sizeof(build_id), sbuild_id);
 127 }
 128
 129 /* asnprintf consolidates asprintf and snprintf */
 130 static int asnprintf(char **strp, size_t size, const char *fmt, ...)
 131 {
 132         va_list ap;
 133         int ret;
 134
 135         if (!strp)
 136                 return -EINVAL;
 137
 138         va_start(ap, fmt);
 139         if (*strp)
 140                 ret = vsnprintf(*strp, size, fmt, ap);
 141         else
 142                 ret = vasprintf(strp, fmt, ap);
 143         va_end(ap);
 144
 145         return ret;
 146 }
 147
 148 char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
 149                                     size_t size)
 150 {
 151         bool retry_old = true;
 152
 153         snprintf(bf, size, "%s/%s/%s/kallsyms",
 154                  buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
 155 retry:
 156         if (!access(bf, F_OK))
 157                 return bf;
 158         if (retry_old) {
 159                 /* Try old style kallsyms cache */
 160                 snprintf(bf, size, "%s/%s/%s",
 161                          buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
 162                 retry_old = false;
 163                 goto retry;
 164         }
 165
 166         return NULL;
 167 }
 168
 169 char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size)
 170 {
 171         char *tmp = bf;
 172         int ret = asnprintf(&bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
 173                             sbuild_id, sbuild_id + 2);
 174         if (ret < 0 || (tmp && size < (unsigned int)ret))
 175                 return NULL;
 176         return bf;
 177 }
 178
 179 char *build_id_cache__origname(const char *sbuild_id)
 180 {
 181         char *linkname;
 182         char buf[PATH_MAX];
 183         char *ret = NULL, *p;
 184         size_t offs = 5;        /* == strlen("../..") */
 185         ssize_t len;
 186
 187         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 188         if (!linkname)
 189                 return NULL;
 190
 191         len = readlink(linkname, buf, sizeof(buf) - 1);
 192         if (len <= 0)
 193                 goto out;
 194         buf[len] = '\0';
 195
 196         /* The link should be "../..<origpath>/<sbuild_id>" */
 197         p = strrchr(buf, '/');  /* Cut off the "/<sbuild_id>" */
 198         if (p && (p > buf + offs)) {
 199                 *p = '\0';
 200                 if (buf[offs + 1] == '[')
 201                         offs++; /*
 202                                  * This is a DSO name, like [kernel.kallsyms].
 203                                  * Skip the first '/', since this is not the
 204                                  * cache of a regular file.
 205                                  */
 206                 ret = strdup(buf + offs);       /* Skip "../..[/]" */
 207         }
 208 out:
 209         free(linkname);
 210         return ret;
 211 }
 212
 213 /* Check if the given build_id cache is valid on current running system */
 214 static bool build_id_cache__valid_id(char *sbuild_id)
 215 {
 216         char real_sbuild_id[SBUILD_ID_SIZE] = "";
 217         char *pathname;
 218         int ret = 0;
 219         bool result = false;
 220
 221         pathname = build_id_cache__origname(sbuild_id);
 222         if (!pathname)
 223                 return false;
 224
 225         if (!strcmp(pathname, DSO__NAME_KALLSYMS))
 226                 ret = sysfs__sprintf_build_id("/", real_sbuild_id);
 227         else if (pathname[0] == '/')
 228                 ret = filename__sprintf_build_id(pathname, real_sbuild_id);
 229         else
 230                 ret = -EINVAL;  /* Should we support other special DSO cache? */
 231         if (ret >= 0)
 232                 result = (strcmp(sbuild_id, real_sbuild_id) == 0);
 233         free(pathname);
 234
 235         return result;
 236 }
 237
 238 static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso)
 239 {
 240         return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : "elf");
 241 }
 242
 243 char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size)
 244 {
 245         bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
 246         bool is_vdso = dso__is_vdso((struct dso *)dso);
 247         char sbuild_id[SBUILD_ID_SIZE];
 248         char *linkname;
 249         bool alloc = (bf == NULL);
 250         int ret;
 251
 252         if (!dso->has_build_id)
 253                 return NULL;
 254
 255         build_id__sprintf(dso->build_id, sizeof(dso->build_id), sbuild_id);
 256         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 257         if (!linkname)
 258                 return NULL;
 259
 260         /* Check if old style build_id cache */
 261         if (is_regular_file(linkname))
 262                 ret = asnprintf(&bf, size, "%s", linkname);
 263         else
 264                 ret = asnprintf(&bf, size, "%s/%s", linkname,
 265                          build_id_cache__basename(is_kallsyms, is_vdso));
 266         if (ret < 0 || (!alloc && size < (unsigned int)ret))
 267                 bf = NULL;
 268         free(linkname);
 269
 270         return bf;
 271 }
 272
 273 bool dso__build_id_is_kmod(const struct dso *dso, char *bf, size_t size)
 274 {
 275         char *id_name = NULL, *ch;
 276         struct stat sb;
 277         char sbuild_id[SBUILD_ID_SIZE];
 278
 279         if (!dso->has_build_id)
 280                 goto err;
 281
 282         build_id__sprintf(dso->build_id, sizeof(dso->build_id), sbuild_id);
 283         id_name = build_id_cache__linkname(sbuild_id, NULL, 0);
 284         if (!id_name)
 285                 goto err;
 286         if (access(id_name, F_OK))
 287                 goto err;
 288         if (lstat(id_name, &sb) == -1)
 289                 goto err;
 290         if ((size_t)sb.st_size > size - 1)
 291                 goto err;
 292         if (readlink(id_name, bf, size - 1) < 0)
 293                 goto err;
 294
 295         bf[sb.st_size] = '\0';
 296
 297         /*
 298          * link should be:
 299          * ../../lib/modules/4.4.0-rc4/kernel/net/ipv4/netfilter/nf_nat_ipv4.ko/a09fe3eb3147dafa4e3b31dbd6257e4d696bdc92
 300          */
 301         ch = strrchr(bf, '/');
 302         if (!ch)
 303                 goto err;
 304         if (ch - 3 < bf)
 305                 goto err;
 306
 307         free(id_name);
 308         return strncmp(".ko", ch - 3, 3) == 0;
 309 err:
 310         pr_err("Invalid build id: %s\n", id_name ? :
 311                                          dso->long_name ? :
 312                                          dso->short_name ? :
 313                                          "[unknown]");
 314         free(id_name);
 315         return false;
 316 }
 317
 318 #define dsos__for_each_with_build_id(pos, head) \
 319         list_for_each_entry(pos, head, node)    \
 320                 if (!pos->has_build_id)         \
 321                         continue;               \
 322                 else
 323
 324 static int write_buildid(const char *name, size_t name_len, u8 *build_id,
 325                          pid_t pid, u16 misc, int fd)
 326 {
 327         int err;
 328         struct build_id_event b;
 329         size_t len;
 330
 331         len = name_len + 1;
 332         len = PERF_ALIGN(len, NAME_ALIGN);
 333
 334         memset(&b, 0, sizeof(b));
 335         memcpy(&b.build_id, build_id, BUILD_ID_SIZE);
 336         b.pid = pid;
 337         b.header.misc = misc;
 338         b.header.size = sizeof(b) + len;
 339
 340         err = writen(fd, &b, sizeof(b));
 341         if (err < 0)
 342                 return err;
 343
 344         return write_padded(fd, name, name_len + 1, len);
 345 }
 346
 347 static int machine__write_buildid_table(struct machine *machine, int fd)
 348 {
 349         int err = 0;
 350         char nm[PATH_MAX];
 351         struct dso *pos;
 352         u16 kmisc = PERF_RECORD_MISC_KERNEL,
 353             umisc = PERF_RECORD_MISC_USER;
 354
 355         if (!machine__is_host(machine)) {
 356                 kmisc = PERF_RECORD_MISC_GUEST_KERNEL;
 357                 umisc = PERF_RECORD_MISC_GUEST_USER;
 358         }
 359
 360         dsos__for_each_with_build_id(pos, &machine->dsos.head) {
 361                 const char *name;
 362                 size_t name_len;
 363                 bool in_kernel = false;
 364
 365                 if (!pos->hit && !dso__is_vdso(pos))
 366                         continue;
 367
 368                 if (dso__is_vdso(pos)) {
 369                         name = pos->short_name;
 370                         name_len = pos->short_name_len;
 371                 } else if (dso__is_kcore(pos)) {
 372                         machine__mmap_name(machine, nm, sizeof(nm));
 373                         name = nm;
 374                         name_len = strlen(nm);
 375                 } else {
 376                         name = pos->long_name;
 377                         name_len = pos->long_name_len;
 378                 }
 379
 380                 in_kernel = pos->kernel ||
 381                                 is_kernel_module(name,
 382                                         PERF_RECORD_MISC_CPUMODE_UNKNOWN);
 383                 err = write_buildid(name, name_len, pos->build_id, machine->pid,
 384                                     in_kernel ? kmisc : umisc, fd);
 385                 if (err)
 386                         break;
 387         }
 388
 389         return err;
 390 }
 391
 392 int perf_session__write_buildid_table(struct perf_session *session, int fd)
 393 {
 394         struct rb_node *nd;
 395         int err = machine__write_buildid_table(&session->machines.host, fd);
 396
 397         if (err)
 398                 return err;
 399
 400         for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
 401                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 402                 err = machine__write_buildid_table(pos, fd);
 403                 if (err)
 404                         break;
 405         }
 406         return err;
 407 }
 408
 409 static int __dsos__hit_all(struct list_head *head)
 410 {
 411         struct dso *pos;
 412
 413         list_for_each_entry(pos, head, node)
 414                 pos->hit = true;
 415
 416         return 0;
 417 }
 418
 419 static int machine__hit_all_dsos(struct machine *machine)
 420 {
 421         return __dsos__hit_all(&machine->dsos.head);
 422 }
 423
 424 int dsos__hit_all(struct perf_session *session)
 425 {
 426         struct rb_node *nd;
 427         int err;
 428
 429         err = machine__hit_all_dsos(&session->machines.host);
 430         if (err)
 431                 return err;
 432
 433         for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
 434                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 435
 436                 err = machine__hit_all_dsos(pos);
 437                 if (err)
 438                         return err;
 439         }
 440
 441         return 0;
 442 }
 443
 444 void disable_buildid_cache(void)
 445 {
 446         no_buildid_cache = true;
 447 }
 448
 449 static bool lsdir_bid_head_filter(const char *name __maybe_unused,
 450                                   struct dirent *d __maybe_unused)
 451 {
 452         return (strlen(d->d_name) == 2) &&
 453                 isxdigit(d->d_name[0]) && isxdigit(d->d_name[1]);
 454 }
 455
 456 static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
 457                                   struct dirent *d __maybe_unused)
 458 {
 459         int i = 0;
 460         while (isxdigit(d->d_name[i]) && i < SBUILD_ID_SIZE - 3)
 461                 i++;
 462         return (i == SBUILD_ID_SIZE - 3) && (d->d_name[i] == '\0');
 463 }
 464
 465 struct strlist *build_id_cache__list_all(bool validonly)
 466 {
 467         struct strlist *toplist, *linklist = NULL, *bidlist;
 468         struct str_node *nd, *nd2;
 469         char *topdir, *linkdir = NULL;
 470         char sbuild_id[SBUILD_ID_SIZE];
 471
 472         /* for filename__ functions */
 473         if (validonly)
 474                 symbol__init(NULL);
 475
 476         /* Open the top-level directory */
 477         if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
 478                 return NULL;
 479
 480         bidlist = strlist__new(NULL, NULL);
 481         if (!bidlist)
 482                 goto out;
 483
 484         toplist = lsdir(topdir, lsdir_bid_head_filter);
 485         if (!toplist) {
 486                 pr_debug("Error in lsdir(%s): %d\n", topdir, errno);
 487                 /* If there is no buildid cache, return an empty list */
 488                 if (errno == ENOENT)
 489                         goto out;
 490                 goto err_out;
 491         }
 492
 493         strlist__for_each_entry(nd, toplist) {
 494                 if (asprintf(&linkdir, "%s/%s", topdir, nd->s) < 0)
 495                         goto err_out;
 496                 /* Open the lower-level directory */
 497                 linklist = lsdir(linkdir, lsdir_bid_tail_filter);
 498                 if (!linklist) {
 499                         pr_debug("Error in lsdir(%s): %d\n", linkdir, errno);
 500                         goto err_out;
 501                 }
 502                 strlist__for_each_entry(nd2, linklist) {
 503                         if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
 504                                      nd->s, nd2->s) != SBUILD_ID_SIZE - 1)
 505                                 goto err_out;
 506                         if (validonly && !build_id_cache__valid_id(sbuild_id))
 507                                 continue;
 508                         if (strlist__add(bidlist, sbuild_id) < 0)
 509                                 goto err_out;
 510                 }
 511                 strlist__delete(linklist);
 512                 zfree(&linkdir);
 513         }
 514
 515 out_free:
 516         strlist__delete(toplist);
 517 out:
 518         free(topdir);
 519
 520         return bidlist;
 521
 522 err_out:
 523         strlist__delete(linklist);
 524         zfree(&linkdir);
 525         strlist__delete(bidlist);
 526         bidlist = NULL;
 527         goto out_free;
 528 }
 529
 530 static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)
 531 {
 532         size_t i;
 533
 534         for (i = 0; i < len; i++) {
 535                 if (!isxdigit(maybe_sbuild_id[i]))
 536                         return false;
 537         }
 538         return true;
 539 }
 540
 541 /* Return the valid complete build-id */
 542 char *build_id_cache__complement(const char *incomplete_sbuild_id)
 543 {
 544         struct strlist *bidlist;
 545         struct str_node *nd, *cand = NULL;
 546         char *sbuild_id = NULL;
 547         size_t len = strlen(incomplete_sbuild_id);
 548
 549         if (len >= SBUILD_ID_SIZE ||
 550             !str_is_build_id(incomplete_sbuild_id, len))
 551                 return NULL;
 552
 553         bidlist = build_id_cache__list_all(true);
 554         if (!bidlist)
 555                 return NULL;
 556
 557         strlist__for_each_entry(nd, bidlist) {
 558                 if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)
 559                         continue;
 560                 if (cand) {     /* Error: There are more than 2 candidates. */
 561                         cand = NULL;
 562                         break;
 563                 }
 564                 cand = nd;
 565         }
 566         if (cand)
 567                 sbuild_id = strdup(cand->s);
 568         strlist__delete(bidlist);
 569
 570         return sbuild_id;
 571 }
 572
 573 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
 574                                bool is_kallsyms, bool is_vdso)
 575 {
 576         char *realname = (char *)name, *filename;
 577         bool slash = is_kallsyms || is_vdso;
 578
 579         if (!slash) {
 580                 realname = realpath(name, NULL);
 581                 if (!realname)
 582                         return NULL;
 583         }
 584
 585         if (asprintf(&filename, "%s%s%s%s%s", buildid_dir, slash ? "/" : "",
 586                      is_vdso ? DSO__NAME_VDSO : realname,
 587                      sbuild_id ? "/" : "", sbuild_id ?: "") < 0)
 588                 filename = NULL;
 589
 590         if (!slash)
 591                 free(realname);
 592
 593         return filename;
 594 }
 595
 596 int build_id_cache__list_build_ids(const char *pathname,
 597                                    struct strlist **result)
 598 {
 599         char *dir_name;
 600         int ret = 0;
 601
 602         dir_name = build_id_cache__cachedir(NULL, pathname, false, false);
 603         if (!dir_name)
 604                 return -ENOMEM;
 605
 606         *result = lsdir(dir_name, lsdir_no_dot_filter);
 607         if (!*result)
 608                 ret = -errno;
 609         free(dir_name);
 610
 611         return ret;
 612 }
 613
 614 #if defined(HAVE_LIBELF_SUPPORT) && defined(HAVE_GELF_GETNOTE_SUPPORT)
 615 static int build_id_cache__add_sdt_cache(const char *sbuild_id,
 616                                           const char *realname)
 617 {
 618         struct probe_cache *cache;
 619         int ret;
 620
 621         cache = probe_cache__new(sbuild_id);
 622         if (!cache)
 623                 return -1;
 624
 625         ret = probe_cache__scan_sdt(cache, realname);
 626         if (ret >= 0) {
 627                 pr_debug4("Found %d SDTs in %s\n", ret, realname);
 628                 if (probe_cache__commit(cache) < 0)
 629                         ret = -1;
 630         }
 631         probe_cache__delete(cache);
 632         return ret;
 633 }
 634 #else
 635 #define build_id_cache__add_sdt_cache(sbuild_id, realname) (0)
 636 #endif
 637
 638 int build_id_cache__add_s(const char *sbuild_id, const char *name,
 639                           bool is_kallsyms, bool is_vdso)
 640 {
 641         const size_t size = PATH_MAX;
 642         char *realname = NULL, *filename = NULL, *dir_name = NULL,
 643              *linkname = zalloc(size), *tmp;
 644         int err = -1;
 645
 646         if (!is_kallsyms) {
 647                 realname = realpath(name, NULL);
 648                 if (!realname)
 649                         goto out_free;
 650         }
 651
 652         dir_name = build_id_cache__cachedir(sbuild_id, name,
 653                                             is_kallsyms, is_vdso);
 654         if (!dir_name)
 655                 goto out_free;
 656
 657         /* Remove old style build-id cache */
 658         if (is_regular_file(dir_name))
 659                 if (unlink(dir_name))
 660                         goto out_free;
 661
 662         if (mkdir_p(dir_name, 0755))
 663                 goto out_free;
 664
 665         /* Save the allocated buildid dirname */
 666         if (asprintf(&filename, "%s/%s", dir_name,
 667                      build_id_cache__basename(is_kallsyms, is_vdso)) < 0) {
 668                 filename = NULL;
 669                 goto out_free;
 670         }
 671
 672         if (access(filename, F_OK)) {
 673                 if (is_kallsyms) {
 674                          if (copyfile("/proc/kallsyms", filename))
 675                                 goto out_free;
 676                 } else if (link(realname, filename) && errno != EEXIST &&
 677                                 copyfile(name, filename))
 678                         goto out_free;
 679         }
 680
 681         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 682                 goto out_free;
 683         tmp = strrchr(linkname, '/');
 684         *tmp = '\0';
 685
 686         if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
 687                 goto out_free;
 688
 689         *tmp = '/';
 690         tmp = dir_name + strlen(buildid_dir) - 5;
 691         memcpy(tmp, "../..", 5);
 692
 693         if (symlink(tmp, linkname) == 0)
 694                 err = 0;
 695
 696         /* Update SDT cache : error is just warned */
 697         if (realname && build_id_cache__add_sdt_cache(sbuild_id, realname) < 0)
 698                 pr_debug4("Failed to update/scan SDT cache for %s\n", realname);
 699
 700 out_free:
 701         if (!is_kallsyms)
 702                 free(realname);
 703         free(filename);
 704         free(dir_name);
 705         free(linkname);
 706         return err;
 707 }
 708
 709 static int build_id_cache__add_b(const u8 *build_id, size_t build_id_size,
 710                                  const char *name, bool is_kallsyms,
 711                                  bool is_vdso)
 712 {
 713         char sbuild_id[SBUILD_ID_SIZE];
 714
 715         build_id__sprintf(build_id, build_id_size, sbuild_id);
 716
 717         return build_id_cache__add_s(sbuild_id, name, is_kallsyms, is_vdso);
 718 }
 719
 720 bool build_id_cache__cached(const char *sbuild_id)
 721 {
 722         bool ret = false;
 723         char *filename = build_id_cache__linkname(sbuild_id, NULL, 0);
 724
 725         if (filename && !access(filename, F_OK))
 726                 ret = true;
 727         free(filename);
 728
 729         return ret;
 730 }
 731
 732 int build_id_cache__remove_s(const char *sbuild_id)
 733 {
 734         const size_t size = PATH_MAX;
 735         char *filename = zalloc(size),
 736              *linkname = zalloc(size), *tmp;
 737         int err = -1;
 738
 739         if (filename == NULL || linkname == NULL)
 740                 goto out_free;
 741
 742         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 743                 goto out_free;
 744
 745         if (access(linkname, F_OK))
 746                 goto out_free;
 747
 748         if (readlink(linkname, filename, size - 1) < 0)
 749                 goto out_free;
 750
 751         if (unlink(linkname))
 752                 goto out_free;
 753
 754         /*
 755          * Since the link is relative, we must make it absolute:
 756          */
 757         tmp = strrchr(linkname, '/') + 1;
 758         snprintf(tmp, size - (tmp - linkname), "%s", filename);
 759
 760         if (rm_rf(linkname))
 761                 goto out_free;
 762
 763         err = 0;
 764 out_free:
 765         free(filename);
 766         free(linkname);
 767         return err;
 768 }
 769
 770 static int dso__cache_build_id(struct dso *dso, struct machine *machine)
 771 {
 772         bool is_kallsyms = dso__is_kallsyms(dso);
 773         bool is_vdso = dso__is_vdso(dso);
 774         const char *name = dso->long_name;
 775         char nm[PATH_MAX];
 776
 777         if (dso__is_kcore(dso)) {
 778                 is_kallsyms = true;
 779                 machine__mmap_name(machine, nm, sizeof(nm));
 780                 name = nm;
 781         }
 782         return build_id_cache__add_b(dso->build_id, sizeof(dso->build_id), name,
 783                                      is_kallsyms, is_vdso);
 784 }
 785
 786 static int __dsos__cache_build_ids(struct list_head *head,
 787                                    struct machine *machine)
 788 {
 789         struct dso *pos;
 790         int err = 0;
 791
 792         dsos__for_each_with_build_id(pos, head)
 793                 if (dso__cache_build_id(pos, machine))
 794                         err = -1;
 795
 796         return err;
 797 }
 798
 799 static int machine__cache_build_ids(struct machine *machine)
 800 {
 801         return __dsos__cache_build_ids(&machine->dsos.head, machine);
 802 }
 803
 804 int perf_session__cache_build_ids(struct perf_session *session)
 805 {
 806         struct rb_node *nd;
 807         int ret;
 808
 809         if (no_buildid_cache)
 810                 return 0;
 811
 812         if (mkdir(buildid_dir, 0755) != 0 && errno != EEXIST)
 813                 return -1;
 814
 815         ret = machine__cache_build_ids(&session->machines.host);
 816
 817         for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
 818                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 819                 ret |= machine__cache_build_ids(pos);
 820         }
 821         return ret ? -1 : 0;
 822 }
 823
 824 static bool machine__read_build_ids(struct machine *machine, bool with_hits)
 825 {
 826         return __dsos__read_build_ids(&machine->dsos.head, with_hits);
 827 }
 828
 829 bool perf_session__read_build_ids(struct perf_session *session, bool with_hits)
 830 {
 831         struct rb_node *nd;
 832         bool ret = machine__read_build_ids(&session->machines.host, with_hits);
 833
 834         for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
 835                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 836                 ret |= machine__read_build_ids(pos, with_hits);
 837         }
 838
 839         return ret;
 840 }