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 <dirent.h>
  11 #include <errno.h>
  12 #include <stdio.h>
  13 #include <sys/stat.h>
  14 #include <sys/types.h>
  15 #include "build-id.h"
  16 #include "event.h"
  17 #include "symbol.h"
  18 #include "thread.h"
  19 #include <linux/kernel.h>
  20 #include "debug.h"
  21 #include "session.h"
  22 #include "tool.h"
  23 #include "header.h"
  24 #include "vdso.h"
  25 #include "path.h"
  26 #include "probe-file.h"
  27 #include "strlist.h"
  28
  29 #include "sane_ctype.h"
  30
  31 static bool no_buildid_cache;
  32
  33 int build_id__mark_dso_hit(struct perf_tool *tool __maybe_unused,
  34                            union perf_event *event,
  35                            struct perf_sample *sample,
  36                            struct perf_evsel *evsel __maybe_unused,
  37                            struct machine *machine)
  38 {
  39         struct addr_location al;
  40         struct thread *thread = machine__findnew_thread(machine, sample->pid,
  41                                                         sample->tid);
  42
  43         if (thread == NULL) {
  44                 pr_err("problem processing %d event, skipping it.\n",
  45                         event->header.type);
  46                 return -1;
  47         }
  48
  49         thread__find_addr_map(thread, sample->cpumode, MAP__FUNCTION, sample->ip, &al);
  50
  51         if (al.map != NULL)
  52                 al.map->dso->hit = 1;
  53
  54         thread__put(thread);
  55         return 0;
  56 }
  57
  58 static int perf_event__exit_del_thread(struct perf_tool *tool __maybe_unused,
  59                                        union perf_event *event,
  60                                        struct perf_sample *sample
  61                                        __maybe_unused,
  62                                        struct machine *machine)
  63 {
  64         struct thread *thread = machine__findnew_thread(machine,
  65                                                         event->fork.pid,
  66                                                         event->fork.tid);
  67
  68         dump_printf("(%d:%d):(%d:%d)\n", event->fork.pid, event->fork.tid,
  69                     event->fork.ppid, event->fork.ptid);
  70
  71         if (thread) {
  72                 machine__remove_thread(machine, thread);
  73                 thread__put(thread);
  74         }
  75
  76         return 0;
  77 }
  78
  79 struct perf_tool build_id__mark_dso_hit_ops = {
  80         .sample = build_id__mark_dso_hit,
  81         .mmap   = perf_event__process_mmap,
  82         .mmap2  = perf_event__process_mmap2,
  83         .fork   = perf_event__process_fork,
  84         .exit   = perf_event__exit_del_thread,
  85         .attr            = perf_event__process_attr,
  86         .build_id        = perf_event__process_build_id,
  87         .ordered_events  = true,
  88 };
  89
  90 int build_id__sprintf(const u8 *build_id, int len, char *bf)
  91 {
  92         char *bid = bf;
  93         const u8 *raw = build_id;
  94         int i;
  95
  96         for (i = 0; i < len; ++i) {
  97                 sprintf(bid, "%02x", *raw);
  98                 ++raw;
  99                 bid += 2;
 100         }
 101
 102         return (bid - bf) + 1;
 103 }
 104
 105 int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id)
 106 {
 107         char notes[PATH_MAX];
 108         u8 build_id[BUILD_ID_SIZE];
 109         int ret;
 110
 111         if (!root_dir)
 112                 root_dir = "";
 113
 114         scnprintf(notes, sizeof(notes), "%s/sys/kernel/notes", root_dir);
 115
 116         ret = sysfs__read_build_id(notes, build_id, sizeof(build_id));
 117         if (ret < 0)
 118                 return ret;
 119
 120         return build_id__sprintf(build_id, sizeof(build_id), sbuild_id);
 121 }
 122
 123 int filename__sprintf_build_id(const char *pathname, char *sbuild_id)
 124 {
 125         u8 build_id[BUILD_ID_SIZE];
 126         int ret;
 127
 128         ret = filename__read_build_id(pathname, build_id, sizeof(build_id));
 129         if (ret < 0)
 130                 return ret;
 131         else if (ret != sizeof(build_id))
 132                 return -EINVAL;
 133
 134         return build_id__sprintf(build_id, sizeof(build_id), sbuild_id);
 135 }
 136
 137 /* asnprintf consolidates asprintf and snprintf */
 138 static int asnprintf(char **strp, size_t size, const char *fmt, ...)
 139 {
 140         va_list ap;
 141         int ret;
 142
 143         if (!strp)
 144                 return -EINVAL;
 145
 146         va_start(ap, fmt);
 147         if (*strp)
 148                 ret = vsnprintf(*strp, size, fmt, ap);
 149         else
 150                 ret = vasprintf(strp, fmt, ap);
 151         va_end(ap);
 152
 153         return ret;
 154 }
 155
 156 char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
 157                                     size_t size)
 158 {
 159         bool retry_old = true;
 160
 161         snprintf(bf, size, "%s/%s/%s/kallsyms",
 162                  buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
 163 retry:
 164         if (!access(bf, F_OK))
 165                 return bf;
 166         if (retry_old) {
 167                 /* Try old style kallsyms cache */
 168                 snprintf(bf, size, "%s/%s/%s",
 169                          buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
 170                 retry_old = false;
 171                 goto retry;
 172         }
 173
 174         return NULL;
 175 }
 176
 177 char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size)
 178 {
 179         char *tmp = bf;
 180         int ret = asnprintf(&bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
 181                             sbuild_id, sbuild_id + 2);
 182         if (ret < 0 || (tmp && size < (unsigned int)ret))
 183                 return NULL;
 184         return bf;
 185 }
 186
 187 char *build_id_cache__origname(const char *sbuild_id)
 188 {
 189         char *linkname;
 190         char buf[PATH_MAX];
 191         char *ret = NULL, *p;
 192         size_t offs = 5;        /* == strlen("../..") */
 193         ssize_t len;
 194
 195         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 196         if (!linkname)
 197                 return NULL;
 198
 199         len = readlink(linkname, buf, sizeof(buf) - 1);
 200         if (len <= 0)
 201                 goto out;
 202         buf[len] = '\0';
 203
 204         /* The link should be "../..<origpath>/<sbuild_id>" */
 205         p = strrchr(buf, '/');  /* Cut off the "/<sbuild_id>" */
 206         if (p && (p > buf + offs)) {
 207                 *p = '\0';
 208                 if (buf[offs + 1] == '[')
 209                         offs++; /*
 210                                  * This is a DSO name, like [kernel.kallsyms].
 211                                  * Skip the first '/', since this is not the
 212                                  * cache of a regular file.
 213                                  */
 214                 ret = strdup(buf + offs);       /* Skip "../..[/]" */
 215         }
 216 out:
 217         free(linkname);
 218         return ret;
 219 }
 220
 221 /* Check if the given build_id cache is valid on current running system */
 222 static bool build_id_cache__valid_id(char *sbuild_id)
 223 {
 224         char real_sbuild_id[SBUILD_ID_SIZE] = "";
 225         char *pathname;
 226         int ret = 0;
 227         bool result = false;
 228
 229         pathname = build_id_cache__origname(sbuild_id);
 230         if (!pathname)
 231                 return false;
 232
 233         if (!strcmp(pathname, DSO__NAME_KALLSYMS))
 234                 ret = sysfs__sprintf_build_id("/", real_sbuild_id);
 235         else if (pathname[0] == '/')
 236                 ret = filename__sprintf_build_id(pathname, real_sbuild_id);
 237         else
 238                 ret = -EINVAL;  /* Should we support other special DSO cache? */
 239         if (ret >= 0)
 240                 result = (strcmp(sbuild_id, real_sbuild_id) == 0);
 241         free(pathname);
 242
 243         return result;
 244 }
 245
 246 static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso,
 247                                             bool is_debug)
 248 {
 249         return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : (is_debug ?
 250             "debug" : "elf"));
 251 }
 252
 253 char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
 254                              bool is_debug)
 255 {
 256         bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
 257         bool is_vdso = dso__is_vdso((struct dso *)dso);
 258         char sbuild_id[SBUILD_ID_SIZE];
 259         char *linkname;
 260         bool alloc = (bf == NULL);
 261         int ret;
 262
 263         if (!dso->has_build_id)
 264                 return NULL;
 265
 266         build_id__sprintf(dso->build_id, sizeof(dso->build_id), sbuild_id);
 267         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 268         if (!linkname)
 269                 return NULL;
 270
 271         /* Check if old style build_id cache */
 272         if (is_regular_file(linkname))
 273                 ret = asnprintf(&bf, size, "%s", linkname);
 274         else
 275                 ret = asnprintf(&bf, size, "%s/%s", linkname,
 276                          build_id_cache__basename(is_kallsyms, is_vdso,
 277                                                   is_debug));
 278         if (ret < 0 || (!alloc && size < (unsigned int)ret))
 279                 bf = NULL;
 280         free(linkname);
 281
 282         return bf;
 283 }
 284
 285 #define dsos__for_each_with_build_id(pos, head) \
 286         list_for_each_entry(pos, head, node)    \
 287                 if (!pos->has_build_id)         \
 288                         continue;               \
 289                 else
 290
 291 static int write_buildid(const char *name, size_t name_len, u8 *build_id,
 292                          pid_t pid, u16 misc, struct feat_fd *fd)
 293 {
 294         int err;
 295         struct build_id_event b;
 296         size_t len;
 297
 298         len = name_len + 1;
 299         len = PERF_ALIGN(len, NAME_ALIGN);
 300
 301         memset(&b, 0, sizeof(b));
 302         memcpy(&b.build_id, build_id, BUILD_ID_SIZE);
 303         b.pid = pid;
 304         b.header.misc = misc;
 305         b.header.size = sizeof(b) + len;
 306
 307         err = do_write(fd, &b, sizeof(b));
 308         if (err < 0)
 309                 return err;
 310
 311         return write_padded(fd, name, name_len + 1, len);
 312 }
 313
 314 static int machine__write_buildid_table(struct machine *machine,
 315                                         struct feat_fd *fd)
 316 {
 317         int err = 0;
 318         char nm[PATH_MAX];
 319         struct dso *pos;
 320         u16 kmisc = PERF_RECORD_MISC_KERNEL,
 321             umisc = PERF_RECORD_MISC_USER;
 322
 323         if (!machine__is_host(machine)) {
 324                 kmisc = PERF_RECORD_MISC_GUEST_KERNEL;
 325                 umisc = PERF_RECORD_MISC_GUEST_USER;
 326         }
 327
 328         dsos__for_each_with_build_id(pos, &machine->dsos.head) {
 329                 const char *name;
 330                 size_t name_len;
 331                 bool in_kernel = false;
 332
 333                 if (!pos->hit && !dso__is_vdso(pos))
 334                         continue;
 335
 336                 if (dso__is_vdso(pos)) {
 337                         name = pos->short_name;
 338                         name_len = pos->short_name_len;
 339                 } else if (dso__is_kcore(pos)) {
 340                         machine__mmap_name(machine, nm, sizeof(nm));
 341                         name = nm;
 342                         name_len = strlen(nm);
 343                 } else {
 344                         name = pos->long_name;
 345                         name_len = pos->long_name_len;
 346                 }
 347
 348                 in_kernel = pos->kernel ||
 349                                 is_kernel_module(name,
 350                                         PERF_RECORD_MISC_CPUMODE_UNKNOWN);
 351                 err = write_buildid(name, name_len, pos->build_id, machine->pid,
 352                                     in_kernel ? kmisc : umisc, fd);
 353                 if (err)
 354                         break;
 355         }
 356
 357         return err;
 358 }
 359
 360 int perf_session__write_buildid_table(struct perf_session *session,
 361                                       struct feat_fd *fd)
 362 {
 363         struct rb_node *nd;
 364         int err = machine__write_buildid_table(&session->machines.host, fd);
 365
 366         if (err)
 367                 return err;
 368
 369         for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
 370                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 371                 err = machine__write_buildid_table(pos, fd);
 372                 if (err)
 373                         break;
 374         }
 375         return err;
 376 }
 377
 378 static int __dsos__hit_all(struct list_head *head)
 379 {
 380         struct dso *pos;
 381
 382         list_for_each_entry(pos, head, node)
 383                 pos->hit = true;
 384
 385         return 0;
 386 }
 387
 388 static int machine__hit_all_dsos(struct machine *machine)
 389 {
 390         return __dsos__hit_all(&machine->dsos.head);
 391 }
 392
 393 int dsos__hit_all(struct perf_session *session)
 394 {
 395         struct rb_node *nd;
 396         int err;
 397
 398         err = machine__hit_all_dsos(&session->machines.host);
 399         if (err)
 400                 return err;
 401
 402         for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
 403                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 404
 405                 err = machine__hit_all_dsos(pos);
 406                 if (err)
 407                         return err;
 408         }
 409
 410         return 0;
 411 }
 412
 413 void disable_buildid_cache(void)
 414 {
 415         no_buildid_cache = true;
 416 }
 417
 418 static bool lsdir_bid_head_filter(const char *name __maybe_unused,
 419                                   struct dirent *d)
 420 {
 421         return (strlen(d->d_name) == 2) &&
 422                 isxdigit(d->d_name[0]) && isxdigit(d->d_name[1]);
 423 }
 424
 425 static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
 426                                   struct dirent *d)
 427 {
 428         int i = 0;
 429         while (isxdigit(d->d_name[i]) && i < SBUILD_ID_SIZE - 3)
 430                 i++;
 431         return (i == SBUILD_ID_SIZE - 3) && (d->d_name[i] == '\0');
 432 }
 433
 434 struct strlist *build_id_cache__list_all(bool validonly)
 435 {
 436         struct strlist *toplist, *linklist = NULL, *bidlist;
 437         struct str_node *nd, *nd2;
 438         char *topdir, *linkdir = NULL;
 439         char sbuild_id[SBUILD_ID_SIZE];
 440
 441         /* for filename__ functions */
 442         if (validonly)
 443                 symbol__init(NULL);
 444
 445         /* Open the top-level directory */
 446         if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
 447                 return NULL;
 448
 449         bidlist = strlist__new(NULL, NULL);
 450         if (!bidlist)
 451                 goto out;
 452
 453         toplist = lsdir(topdir, lsdir_bid_head_filter);
 454         if (!toplist) {
 455                 pr_debug("Error in lsdir(%s): %d\n", topdir, errno);
 456                 /* If there is no buildid cache, return an empty list */
 457                 if (errno == ENOENT)
 458                         goto out;
 459                 goto err_out;
 460         }
 461
 462         strlist__for_each_entry(nd, toplist) {
 463                 if (asprintf(&linkdir, "%s/%s", topdir, nd->s) < 0)
 464                         goto err_out;
 465                 /* Open the lower-level directory */
 466                 linklist = lsdir(linkdir, lsdir_bid_tail_filter);
 467                 if (!linklist) {
 468                         pr_debug("Error in lsdir(%s): %d\n", linkdir, errno);
 469                         goto err_out;
 470                 }
 471                 strlist__for_each_entry(nd2, linklist) {
 472                         if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
 473                                      nd->s, nd2->s) != SBUILD_ID_SIZE - 1)
 474                                 goto err_out;
 475                         if (validonly && !build_id_cache__valid_id(sbuild_id))
 476                                 continue;
 477                         if (strlist__add(bidlist, sbuild_id) < 0)
 478                                 goto err_out;
 479                 }
 480                 strlist__delete(linklist);
 481                 zfree(&linkdir);
 482         }
 483
 484 out_free:
 485         strlist__delete(toplist);
 486 out:
 487         free(topdir);
 488
 489         return bidlist;
 490
 491 err_out:
 492         strlist__delete(linklist);
 493         zfree(&linkdir);
 494         strlist__delete(bidlist);
 495         bidlist = NULL;
 496         goto out_free;
 497 }
 498
 499 static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)
 500 {
 501         size_t i;
 502
 503         for (i = 0; i < len; i++) {
 504                 if (!isxdigit(maybe_sbuild_id[i]))
 505                         return false;
 506         }
 507         return true;
 508 }
 509
 510 /* Return the valid complete build-id */
 511 char *build_id_cache__complement(const char *incomplete_sbuild_id)
 512 {
 513         struct strlist *bidlist;
 514         struct str_node *nd, *cand = NULL;
 515         char *sbuild_id = NULL;
 516         size_t len = strlen(incomplete_sbuild_id);
 517
 518         if (len >= SBUILD_ID_SIZE ||
 519             !str_is_build_id(incomplete_sbuild_id, len))
 520                 return NULL;
 521
 522         bidlist = build_id_cache__list_all(true);
 523         if (!bidlist)
 524                 return NULL;
 525
 526         strlist__for_each_entry(nd, bidlist) {
 527                 if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)
 528                         continue;
 529                 if (cand) {     /* Error: There are more than 2 candidates. */
 530                         cand = NULL;
 531                         break;
 532                 }
 533                 cand = nd;
 534         }
 535         if (cand)
 536                 sbuild_id = strdup(cand->s);
 537         strlist__delete(bidlist);
 538
 539         return sbuild_id;
 540 }
 541
 542 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
 543                                struct nsinfo *nsi, bool is_kallsyms,
 544                                bool is_vdso)
 545 {
 546         char *realname = (char *)name, *filename;
 547         bool slash = is_kallsyms || is_vdso;
 548
 549         if (!slash) {
 550                 realname = nsinfo__realpath(name, nsi);
 551                 if (!realname)
 552                         return NULL;
 553         }
 554
 555         if (asprintf(&filename, "%s%s%s%s%s", buildid_dir, slash ? "/" : "",
 556                      is_vdso ? DSO__NAME_VDSO : realname,
 557                      sbuild_id ? "/" : "", sbuild_id ?: "") < 0)
 558                 filename = NULL;
 559
 560         if (!slash)
 561                 free(realname);
 562
 563         return filename;
 564 }
 565
 566 int build_id_cache__list_build_ids(const char *pathname, struct nsinfo *nsi,
 567                                    struct strlist **result)
 568 {
 569         char *dir_name;
 570         int ret = 0;
 571
 572         dir_name = build_id_cache__cachedir(NULL, pathname, nsi, false, false);
 573         if (!dir_name)
 574                 return -ENOMEM;
 575
 576         *result = lsdir(dir_name, lsdir_no_dot_filter);
 577         if (!*result)
 578                 ret = -errno;
 579         free(dir_name);
 580
 581         return ret;
 582 }
 583
 584 #if defined(HAVE_LIBELF_SUPPORT) && defined(HAVE_GELF_GETNOTE_SUPPORT)
 585 static int build_id_cache__add_sdt_cache(const char *sbuild_id,
 586                                           const char *realname,
 587                                           struct nsinfo *nsi)
 588 {
 589         struct probe_cache *cache;
 590         int ret;
 591         struct nscookie nsc;
 592
 593         cache = probe_cache__new(sbuild_id, nsi);
 594         if (!cache)
 595                 return -1;
 596
 597         nsinfo__mountns_enter(nsi, &nsc);
 598         ret = probe_cache__scan_sdt(cache, realname);
 599         nsinfo__mountns_exit(&nsc);
 600         if (ret >= 0) {
 601                 pr_debug4("Found %d SDTs in %s\n", ret, realname);
 602                 if (probe_cache__commit(cache) < 0)
 603                         ret = -1;
 604         }
 605         probe_cache__delete(cache);
 606         return ret;
 607 }
 608 #else
 609 #define build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) (0)
 610 #endif
 611
 612 static char *build_id_cache__find_debug(const char *sbuild_id,
 613                                         struct nsinfo *nsi)
 614 {
 615         char *realname = NULL;
 616         char *debugfile;
 617         struct nscookie nsc;
 618         size_t len = 0;
 619
 620         debugfile = calloc(1, PATH_MAX);
 621         if (!debugfile)
 622                 goto out;
 623
 624         len = __symbol__join_symfs(debugfile, PATH_MAX,
 625                                    "/usr/lib/debug/.build-id/");
 626         snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,
 627                  sbuild_id + 2);
 628
 629         nsinfo__mountns_enter(nsi, &nsc);
 630         realname = realpath(debugfile, NULL);
 631         if (realname && access(realname, R_OK))
 632                 zfree(&realname);
 633         nsinfo__mountns_exit(&nsc);
 634 out:
 635         free(debugfile);
 636         return realname;
 637 }
 638
 639 int build_id_cache__add_s(const char *sbuild_id, const char *name,
 640                           struct nsinfo *nsi, bool is_kallsyms, bool is_vdso)
 641 {
 642         const size_t size = PATH_MAX;
 643         char *realname = NULL, *filename = NULL, *dir_name = NULL,
 644              *linkname = zalloc(size), *tmp;
 645         char *debugfile = NULL;
 646         int err = -1;
 647
 648         if (!is_kallsyms) {
 649                 if (!is_vdso)
 650                         realname = nsinfo__realpath(name, nsi);
 651                 else
 652                         realname = realpath(name, NULL);
 653                 if (!realname)
 654                         goto out_free;
 655         }
 656
 657         dir_name = build_id_cache__cachedir(sbuild_id, name, nsi, is_kallsyms,
 658                                             is_vdso);
 659         if (!dir_name)
 660                 goto out_free;
 661
 662         /* Remove old style build-id cache */
 663         if (is_regular_file(dir_name))
 664                 if (unlink(dir_name))
 665                         goto out_free;
 666
 667         if (mkdir_p(dir_name, 0755))
 668                 goto out_free;
 669
 670         /* Save the allocated buildid dirname */
 671         if (asprintf(&filename, "%s/%s", dir_name,
 672                      build_id_cache__basename(is_kallsyms, is_vdso,
 673                      false)) < 0) {
 674                 filename = NULL;
 675                 goto out_free;
 676         }
 677
 678         if (access(filename, F_OK)) {
 679                 if (is_kallsyms) {
 680                         if (copyfile("/proc/kallsyms", filename))
 681                                 goto out_free;
 682                 } else if (nsi && nsi->need_setns) {
 683                         if (copyfile_ns(name, filename, nsi))
 684                                 goto out_free;
 685                 } else if (link(realname, filename) && errno != EEXIST &&
 686                                 copyfile(name, filename))
 687                         goto out_free;
 688         }
 689
 690         /* Some binaries are stripped, but have .debug files with their symbol
 691          * table.  Check to see if we can locate one of those, since the elf
 692          * file itself may not be very useful to users of our tools without a
 693          * symtab.
 694          */
 695         if (!is_kallsyms && !is_vdso &&
 696             strncmp(".ko", name + strlen(name) - 3, 3)) {
 697                 debugfile = build_id_cache__find_debug(sbuild_id, nsi);
 698                 if (debugfile) {
 699                         zfree(&filename);
 700                         if (asprintf(&filename, "%s/%s", dir_name,
 701                             build_id_cache__basename(false, false, true)) < 0) {
 702                                 filename = NULL;
 703                                 goto out_free;
 704                         }
 705                         if (access(filename, F_OK)) {
 706                                 if (nsi && nsi->need_setns) {
 707                                         if (copyfile_ns(debugfile, filename,
 708                                                         nsi))
 709                                                 goto out_free;
 710                                 } else if (link(debugfile, filename) &&
 711                                                 errno != EEXIST &&
 712                                                 copyfile(debugfile, filename))
 713                                         goto out_free;
 714                         }
 715                 }
 716         }
 717
 718         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 719                 goto out_free;
 720         tmp = strrchr(linkname, '/');
 721         *tmp = '\0';
 722
 723         if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
 724                 goto out_free;
 725
 726         *tmp = '/';
 727         tmp = dir_name + strlen(buildid_dir) - 5;
 728         memcpy(tmp, "../..", 5);
 729
 730         if (symlink(tmp, linkname) == 0)
 731                 err = 0;
 732
 733         /* Update SDT cache : error is just warned */
 734         if (realname &&
 735             build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) < 0)
 736                 pr_debug4("Failed to update/scan SDT cache for %s\n", realname);
 737
 738 out_free:
 739         if (!is_kallsyms)
 740                 free(realname);
 741         free(filename);
 742         free(debugfile);
 743         free(dir_name);
 744         free(linkname);
 745         return err;
 746 }
 747
 748 static int build_id_cache__add_b(const u8 *build_id, size_t build_id_size,
 749                                  const char *name, struct nsinfo *nsi,
 750                                  bool is_kallsyms, bool is_vdso)
 751 {
 752         char sbuild_id[SBUILD_ID_SIZE];
 753
 754         build_id__sprintf(build_id, build_id_size, sbuild_id);
 755
 756         return build_id_cache__add_s(sbuild_id, name, nsi, is_kallsyms,
 757                                      is_vdso);
 758 }
 759
 760 bool build_id_cache__cached(const char *sbuild_id)
 761 {
 762         bool ret = false;
 763         char *filename = build_id_cache__linkname(sbuild_id, NULL, 0);
 764
 765         if (filename && !access(filename, F_OK))
 766                 ret = true;
 767         free(filename);
 768
 769         return ret;
 770 }
 771
 772 int build_id_cache__remove_s(const char *sbuild_id)
 773 {
 774         const size_t size = PATH_MAX;
 775         char *filename = zalloc(size),
 776              *linkname = zalloc(size), *tmp;
 777         int err = -1;
 778
 779         if (filename == NULL || linkname == NULL)
 780                 goto out_free;
 781
 782         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 783                 goto out_free;
 784
 785         if (access(linkname, F_OK))
 786                 goto out_free;
 787
 788         if (readlink(linkname, filename, size - 1) < 0)
 789                 goto out_free;
 790
 791         if (unlink(linkname))
 792                 goto out_free;
 793
 794         /*
 795          * Since the link is relative, we must make it absolute:
 796          */
 797         tmp = strrchr(linkname, '/') + 1;
 798         snprintf(tmp, size - (tmp - linkname), "%s", filename);
 799
 800         if (rm_rf(linkname))
 801                 goto out_free;
 802
 803         err = 0;
 804 out_free:
 805         free(filename);
 806         free(linkname);
 807         return err;
 808 }
 809
 810 static int dso__cache_build_id(struct dso *dso, struct machine *machine)
 811 {
 812         bool is_kallsyms = dso__is_kallsyms(dso);
 813         bool is_vdso = dso__is_vdso(dso);
 814         const char *name = dso->long_name;
 815         char nm[PATH_MAX];
 816
 817         if (dso__is_kcore(dso)) {
 818                 is_kallsyms = true;
 819                 machine__mmap_name(machine, nm, sizeof(nm));
 820                 name = nm;
 821         }
 822         return build_id_cache__add_b(dso->build_id, sizeof(dso->build_id), name,
 823                                      dso->nsinfo, is_kallsyms, is_vdso);
 824 }
 825
 826 static int __dsos__cache_build_ids(struct list_head *head,
 827                                    struct machine *machine)
 828 {
 829         struct dso *pos;
 830         int err = 0;
 831
 832         dsos__for_each_with_build_id(pos, head)
 833                 if (dso__cache_build_id(pos, machine))
 834                         err = -1;
 835
 836         return err;
 837 }
 838
 839 static int machine__cache_build_ids(struct machine *machine)
 840 {
 841         return __dsos__cache_build_ids(&machine->dsos.head, machine);
 842 }
 843
 844 int perf_session__cache_build_ids(struct perf_session *session)
 845 {
 846         struct rb_node *nd;
 847         int ret;
 848
 849         if (no_buildid_cache)
 850                 return 0;
 851
 852         if (mkdir(buildid_dir, 0755) != 0 && errno != EEXIST)
 853                 return -1;
 854
 855         ret = machine__cache_build_ids(&session->machines.host);
 856
 857         for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
 858                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 859                 ret |= machine__cache_build_ids(pos);
 860         }
 861         return ret ? -1 : 0;
 862 }
 863
 864 static bool machine__read_build_ids(struct machine *machine, bool with_hits)
 865 {
 866         return __dsos__read_build_ids(&machine->dsos.head, with_hits);
 867 }
 868
 869 bool perf_session__read_build_ids(struct perf_session *session, bool with_hits)
 870 {
 871         struct rb_node *nd;
 872         bool ret = machine__read_build_ids(&session->machines.host, with_hits);
 873
 874         for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
 875                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 876                 ret |= machine__read_build_ids(pos, with_hits);
 877         }
 878
 879         return ret;
 880 }