tools/perf/util/build-id.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * build-id.c
   4  *
   5  * build-id support
   6  *
   7  * Copyright (C) 2009, 2010 Red Hat Inc.
   8  * Copyright (C) 2009, 2010 Arnaldo Carvalho de Melo <acme@redhat.com>
   9  */
  10 #include "util.h"
  11 #include <dirent.h>
  12 #include <errno.h>
  13 #include <stdio.h>
  14 #include <sys/stat.h>
  15 #include <sys/types.h>
  16 #include "build-id.h"
  17 #include "event.h"
  18 #include "namespaces.h"
  19 #include "map.h"
  20 #include "symbol.h"
  21 #include "thread.h"
  22 #include <linux/kernel.h>
  23 #include "debug.h"
  24 #include "session.h"
  25 #include "tool.h"
  26 #include "header.h"
  27 #include "vdso.h"
  28 #include "path.h"
  29 #include "probe-file.h"
  30 #include "strlist.h"
  31
  32 #include "sane_ctype.h"
  33
  34 static bool no_buildid_cache;
  35
  36 int build_id__mark_dso_hit(struct perf_tool *tool __maybe_unused,
  37                            union perf_event *event,
  38                            struct perf_sample *sample,
  39                            struct perf_evsel *evsel __maybe_unused,
  40                            struct machine *machine)
  41 {
  42         struct addr_location al;
  43         struct thread *thread = machine__findnew_thread(machine, sample->pid,
  44                                                         sample->tid);
  45
  46         if (thread == NULL) {
  47                 pr_err("problem processing %d event, skipping it.\n",
  48                         event->header.type);
  49                 return -1;
  50         }
  51
  52         if (thread__find_map(thread, sample->cpumode, sample->ip, &al))
  53                 al.map->dso->hit = 1;
  54
  55         thread__put(thread);
  56         return 0;
  57 }
  58
  59 static int perf_event__exit_del_thread(struct perf_tool *tool __maybe_unused,
  60                                        union perf_event *event,
  61                                        struct perf_sample *sample
  62                                        __maybe_unused,
  63                                        struct machine *machine)
  64 {
  65         struct thread *thread = machine__findnew_thread(machine,
  66                                                         event->fork.pid,
  67                                                         event->fork.tid);
  68
  69         dump_printf("(%d:%d):(%d:%d)\n", event->fork.pid, event->fork.tid,
  70                     event->fork.ppid, event->fork.ptid);
  71
  72         if (thread) {
  73                 machine__remove_thread(machine, thread);
  74                 thread__put(thread);
  75         }
  76
  77         return 0;
  78 }
  79
  80 struct perf_tool build_id__mark_dso_hit_ops = {
  81         .sample = build_id__mark_dso_hit,
  82         .mmap   = perf_event__process_mmap,
  83         .mmap2  = perf_event__process_mmap2,
  84         .fork   = perf_event__process_fork,
  85         .exit   = perf_event__exit_del_thread,
  86         .attr            = perf_event__process_attr,
  87         .build_id        = perf_event__process_build_id,
  88         .ordered_events  = true,
  89 };
  90
  91 int build_id__sprintf(const u8 *build_id, int len, char *bf)
  92 {
  93         char *bid = bf;
  94         const u8 *raw = build_id;
  95         int i;
  96
  97         for (i = 0; i < len; ++i) {
  98                 sprintf(bid, "%02x", *raw);
  99                 ++raw;
 100                 bid += 2;
 101         }
 102
 103         return (bid - bf) + 1;
 104 }
 105
 106 int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id)
 107 {
 108         char notes[PATH_MAX];
 109         u8 build_id[BUILD_ID_SIZE];
 110         int ret;
 111
 112         if (!root_dir)
 113                 root_dir = "";
 114
 115         scnprintf(notes, sizeof(notes), "%s/sys/kernel/notes", root_dir);
 116
 117         ret = sysfs__read_build_id(notes, build_id, sizeof(build_id));
 118         if (ret < 0)
 119                 return ret;
 120
 121         return build_id__sprintf(build_id, sizeof(build_id), sbuild_id);
 122 }
 123
 124 int filename__sprintf_build_id(const char *pathname, char *sbuild_id)
 125 {
 126         u8 build_id[BUILD_ID_SIZE];
 127         int ret;
 128
 129         ret = filename__read_build_id(pathname, build_id, sizeof(build_id));
 130         if (ret < 0)
 131                 return ret;
 132         else if (ret != sizeof(build_id))
 133                 return -EINVAL;
 134
 135         return build_id__sprintf(build_id, sizeof(build_id), sbuild_id);
 136 }
 137
 138 /* asnprintf consolidates asprintf and snprintf */
 139 static int asnprintf(char **strp, size_t size, const char *fmt, ...)
 140 {
 141         va_list ap;
 142         int ret;
 143
 144         if (!strp)
 145                 return -EINVAL;
 146
 147         va_start(ap, fmt);
 148         if (*strp)
 149                 ret = vsnprintf(*strp, size, fmt, ap);
 150         else
 151                 ret = vasprintf(strp, fmt, ap);
 152         va_end(ap);
 153
 154         return ret;
 155 }
 156
 157 char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
 158                                     size_t size)
 159 {
 160         bool retry_old = true;
 161
 162         snprintf(bf, size, "%s/%s/%s/kallsyms",
 163                  buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
 164 retry:
 165         if (!access(bf, F_OK))
 166                 return bf;
 167         if (retry_old) {
 168                 /* Try old style kallsyms cache */
 169                 snprintf(bf, size, "%s/%s/%s",
 170                          buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
 171                 retry_old = false;
 172                 goto retry;
 173         }
 174
 175         return NULL;
 176 }
 177
 178 char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size)
 179 {
 180         char *tmp = bf;
 181         int ret = asnprintf(&bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
 182                             sbuild_id, sbuild_id + 2);
 183         if (ret < 0 || (tmp && size < (unsigned int)ret))
 184                 return NULL;
 185         return bf;
 186 }
 187
 188 /* The caller is responsible to free the returned buffer. */
 189 char *build_id_cache__origname(const char *sbuild_id)
 190 {
 191         char *linkname;
 192         char buf[PATH_MAX];
 193         char *ret = NULL, *p;
 194         size_t offs = 5;        /* == strlen("../..") */
 195         ssize_t len;
 196
 197         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 198         if (!linkname)
 199                 return NULL;
 200
 201         len = readlink(linkname, buf, sizeof(buf) - 1);
 202         if (len <= 0)
 203                 goto out;
 204         buf[len] = '\0';
 205
 206         /* The link should be "../..<origpath>/<sbuild_id>" */
 207         p = strrchr(buf, '/');  /* Cut off the "/<sbuild_id>" */
 208         if (p && (p > buf + offs)) {
 209                 *p = '\0';
 210                 if (buf[offs + 1] == '[')
 211                         offs++; /*
 212                                  * This is a DSO name, like [kernel.kallsyms].
 213                                  * Skip the first '/', since this is not the
 214                                  * cache of a regular file.
 215                                  */
 216                 ret = strdup(buf + offs);       /* Skip "../..[/]" */
 217         }
 218 out:
 219         free(linkname);
 220         return ret;
 221 }
 222
 223 /* Check if the given build_id cache is valid on current running system */
 224 static bool build_id_cache__valid_id(char *sbuild_id)
 225 {
 226         char real_sbuild_id[SBUILD_ID_SIZE] = "";
 227         char *pathname;
 228         int ret = 0;
 229         bool result = false;
 230
 231         pathname = build_id_cache__origname(sbuild_id);
 232         if (!pathname)
 233                 return false;
 234
 235         if (!strcmp(pathname, DSO__NAME_KALLSYMS))
 236                 ret = sysfs__sprintf_build_id("/", real_sbuild_id);
 237         else if (pathname[0] == '/')
 238                 ret = filename__sprintf_build_id(pathname, real_sbuild_id);
 239         else
 240                 ret = -EINVAL;  /* Should we support other special DSO cache? */
 241         if (ret >= 0)
 242                 result = (strcmp(sbuild_id, real_sbuild_id) == 0);
 243         free(pathname);
 244
 245         return result;
 246 }
 247
 248 static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso,
 249                                             bool is_debug)
 250 {
 251         return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : (is_debug ?
 252             "debug" : "elf"));
 253 }
 254
 255 char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
 256                              bool is_debug)
 257 {
 258         bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
 259         bool is_vdso = dso__is_vdso((struct dso *)dso);
 260         char sbuild_id[SBUILD_ID_SIZE];
 261         char *linkname;
 262         bool alloc = (bf == NULL);
 263         int ret;
 264
 265         if (!dso->has_build_id)
 266                 return NULL;
 267
 268         build_id__sprintf(dso->build_id, sizeof(dso->build_id), sbuild_id);
 269         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 270         if (!linkname)
 271                 return NULL;
 272
 273         /* Check if old style build_id cache */
 274         if (is_regular_file(linkname))
 275                 ret = asnprintf(&bf, size, "%s", linkname);
 276         else
 277                 ret = asnprintf(&bf, size, "%s/%s", linkname,
 278                          build_id_cache__basename(is_kallsyms, is_vdso,
 279                                                   is_debug));
 280         if (ret < 0 || (!alloc && size < (unsigned int)ret))
 281                 bf = NULL;
 282         free(linkname);
 283
 284         return bf;
 285 }
 286
 287 #define dsos__for_each_with_build_id(pos, head) \
 288         list_for_each_entry(pos, head, node)    \
 289                 if (!pos->has_build_id)         \
 290                         continue;               \
 291                 else
 292
 293 static int write_buildid(const char *name, size_t name_len, u8 *build_id,
 294                          pid_t pid, u16 misc, struct feat_fd *fd)
 295 {
 296         int err;
 297         struct build_id_event b;
 298         size_t len;
 299
 300         len = name_len + 1;
 301         len = PERF_ALIGN(len, NAME_ALIGN);
 302
 303         memset(&b, 0, sizeof(b));
 304         memcpy(&b.build_id, build_id, BUILD_ID_SIZE);
 305         b.pid = pid;
 306         b.header.misc = misc;
 307         b.header.size = sizeof(b) + len;
 308
 309         err = do_write(fd, &b, sizeof(b));
 310         if (err < 0)
 311                 return err;
 312
 313         return write_padded(fd, name, name_len + 1, len);
 314 }
 315
 316 static int machine__write_buildid_table(struct machine *machine,
 317                                         struct feat_fd *fd)
 318 {
 319         int err = 0;
 320         struct dso *pos;
 321         u16 kmisc = PERF_RECORD_MISC_KERNEL,
 322             umisc = PERF_RECORD_MISC_USER;
 323
 324         if (!machine__is_host(machine)) {
 325                 kmisc = PERF_RECORD_MISC_GUEST_KERNEL;
 326                 umisc = PERF_RECORD_MISC_GUEST_USER;
 327         }
 328
 329         dsos__for_each_with_build_id(pos, &machine->dsos.head) {
 330                 const char *name;
 331                 size_t name_len;
 332                 bool in_kernel = false;
 333
 334                 if (!pos->hit && !dso__is_vdso(pos))
 335                         continue;
 336
 337                 if (dso__is_vdso(pos)) {
 338                         name = pos->short_name;
 339                         name_len = pos->short_name_len;
 340                 } else if (dso__is_kcore(pos)) {
 341                         name = machine->mmap_name;
 342                         name_len = strlen(name);
 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_cached(&session->machines.guests); nd;
 370              nd = rb_next(nd)) {
 371                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 372                 err = machine__write_buildid_table(pos, fd);
 373                 if (err)
 374                         break;
 375         }
 376         return err;
 377 }
 378
 379 static int __dsos__hit_all(struct list_head *head)
 380 {
 381         struct dso *pos;
 382
 383         list_for_each_entry(pos, head, node)
 384                 pos->hit = true;
 385
 386         return 0;
 387 }
 388
 389 static int machine__hit_all_dsos(struct machine *machine)
 390 {
 391         return __dsos__hit_all(&machine->dsos.head);
 392 }
 393
 394 int dsos__hit_all(struct perf_session *session)
 395 {
 396         struct rb_node *nd;
 397         int err;
 398
 399         err = machine__hit_all_dsos(&session->machines.host);
 400         if (err)
 401                 return err;
 402
 403         for (nd = rb_first_cached(&session->machines.guests); nd;
 404              nd = rb_next(nd)) {
 405                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 406
 407                 err = machine__hit_all_dsos(pos);
 408                 if (err)
 409                         return err;
 410         }
 411
 412         return 0;
 413 }
 414
 415 void disable_buildid_cache(void)
 416 {
 417         no_buildid_cache = true;
 418 }
 419
 420 static bool lsdir_bid_head_filter(const char *name __maybe_unused,
 421                                   struct dirent *d)
 422 {
 423         return (strlen(d->d_name) == 2) &&
 424                 isxdigit(d->d_name[0]) && isxdigit(d->d_name[1]);
 425 }
 426
 427 static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
 428                                   struct dirent *d)
 429 {
 430         int i = 0;
 431         while (isxdigit(d->d_name[i]) && i < SBUILD_ID_SIZE - 3)
 432                 i++;
 433         return (i == SBUILD_ID_SIZE - 3) && (d->d_name[i] == '\0');
 434 }
 435
 436 struct strlist *build_id_cache__list_all(bool validonly)
 437 {
 438         struct strlist *toplist, *linklist = NULL, *bidlist;
 439         struct str_node *nd, *nd2;
 440         char *topdir, *linkdir = NULL;
 441         char sbuild_id[SBUILD_ID_SIZE];
 442
 443         /* for filename__ functions */
 444         if (validonly)
 445                 symbol__init(NULL);
 446
 447         /* Open the top-level directory */
 448         if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
 449                 return NULL;
 450
 451         bidlist = strlist__new(NULL, NULL);
 452         if (!bidlist)
 453                 goto out;
 454
 455         toplist = lsdir(topdir, lsdir_bid_head_filter);
 456         if (!toplist) {
 457                 pr_debug("Error in lsdir(%s): %d\n", topdir, errno);
 458                 /* If there is no buildid cache, return an empty list */
 459                 if (errno == ENOENT)
 460                         goto out;
 461                 goto err_out;
 462         }
 463
 464         strlist__for_each_entry(nd, toplist) {
 465                 if (asprintf(&linkdir, "%s/%s", topdir, nd->s) < 0)
 466                         goto err_out;
 467                 /* Open the lower-level directory */
 468                 linklist = lsdir(linkdir, lsdir_bid_tail_filter);
 469                 if (!linklist) {
 470                         pr_debug("Error in lsdir(%s): %d\n", linkdir, errno);
 471                         goto err_out;
 472                 }
 473                 strlist__for_each_entry(nd2, linklist) {
 474                         if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
 475                                      nd->s, nd2->s) != SBUILD_ID_SIZE - 1)
 476                                 goto err_out;
 477                         if (validonly && !build_id_cache__valid_id(sbuild_id))
 478                                 continue;
 479                         if (strlist__add(bidlist, sbuild_id) < 0)
 480                                 goto err_out;
 481                 }
 482                 strlist__delete(linklist);
 483                 zfree(&linkdir);
 484         }
 485
 486 out_free:
 487         strlist__delete(toplist);
 488 out:
 489         free(topdir);
 490
 491         return bidlist;
 492
 493 err_out:
 494         strlist__delete(linklist);
 495         zfree(&linkdir);
 496         strlist__delete(bidlist);
 497         bidlist = NULL;
 498         goto out_free;
 499 }
 500
 501 static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)
 502 {
 503         size_t i;
 504
 505         for (i = 0; i < len; i++) {
 506                 if (!isxdigit(maybe_sbuild_id[i]))
 507                         return false;
 508         }
 509         return true;
 510 }
 511
 512 /* Return the valid complete build-id */
 513 char *build_id_cache__complement(const char *incomplete_sbuild_id)
 514 {
 515         struct strlist *bidlist;
 516         struct str_node *nd, *cand = NULL;
 517         char *sbuild_id = NULL;
 518         size_t len = strlen(incomplete_sbuild_id);
 519
 520         if (len >= SBUILD_ID_SIZE ||
 521             !str_is_build_id(incomplete_sbuild_id, len))
 522                 return NULL;
 523
 524         bidlist = build_id_cache__list_all(true);
 525         if (!bidlist)
 526                 return NULL;
 527
 528         strlist__for_each_entry(nd, bidlist) {
 529                 if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)
 530                         continue;
 531                 if (cand) {     /* Error: There are more than 2 candidates. */
 532                         cand = NULL;
 533                         break;
 534                 }
 535                 cand = nd;
 536         }
 537         if (cand)
 538                 sbuild_id = strdup(cand->s);
 539         strlist__delete(bidlist);
 540
 541         return sbuild_id;
 542 }
 543
 544 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
 545                                struct nsinfo *nsi, bool is_kallsyms,
 546                                bool is_vdso)
 547 {
 548         char *realname = (char *)name, *filename;
 549         bool slash = is_kallsyms || is_vdso;
 550
 551         if (!slash) {
 552                 realname = nsinfo__realpath(name, nsi);
 553                 if (!realname)
 554                         return NULL;
 555         }
 556
 557         if (asprintf(&filename, "%s%s%s%s%s", buildid_dir, slash ? "/" : "",
 558                      is_vdso ? DSO__NAME_VDSO : realname,
 559                      sbuild_id ? "/" : "", sbuild_id ?: "") < 0)
 560                 filename = NULL;
 561
 562         if (!slash)
 563                 free(realname);
 564
 565         return filename;
 566 }
 567
 568 int build_id_cache__list_build_ids(const char *pathname, struct nsinfo *nsi,
 569                                    struct strlist **result)
 570 {
 571         char *dir_name;
 572         int ret = 0;
 573
 574         dir_name = build_id_cache__cachedir(NULL, pathname, nsi, false, false);
 575         if (!dir_name)
 576                 return -ENOMEM;
 577
 578         *result = lsdir(dir_name, lsdir_no_dot_filter);
 579         if (!*result)
 580                 ret = -errno;
 581         free(dir_name);
 582
 583         return ret;
 584 }
 585
 586 #if defined(HAVE_LIBELF_SUPPORT) && defined(HAVE_GELF_GETNOTE_SUPPORT)
 587 static int build_id_cache__add_sdt_cache(const char *sbuild_id,
 588                                           const char *realname,
 589                                           struct nsinfo *nsi)
 590 {
 591         struct probe_cache *cache;
 592         int ret;
 593         struct nscookie nsc;
 594
 595         cache = probe_cache__new(sbuild_id, nsi);
 596         if (!cache)
 597                 return -1;
 598
 599         nsinfo__mountns_enter(nsi, &nsc);
 600         ret = probe_cache__scan_sdt(cache, realname);
 601         nsinfo__mountns_exit(&nsc);
 602         if (ret >= 0) {
 603                 pr_debug4("Found %d SDTs in %s\n", ret, realname);
 604                 if (probe_cache__commit(cache) < 0)
 605                         ret = -1;
 606         }
 607         probe_cache__delete(cache);
 608         return ret;
 609 }
 610 #else
 611 #define build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) (0)
 612 #endif
 613
 614 static char *build_id_cache__find_debug(const char *sbuild_id,
 615                                         struct nsinfo *nsi)
 616 {
 617         char *realname = NULL;
 618         char *debugfile;
 619         struct nscookie nsc;
 620         size_t len = 0;
 621
 622         debugfile = calloc(1, PATH_MAX);
 623         if (!debugfile)
 624                 goto out;
 625
 626         len = __symbol__join_symfs(debugfile, PATH_MAX,
 627                                    "/usr/lib/debug/.build-id/");
 628         snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,
 629                  sbuild_id + 2);
 630
 631         nsinfo__mountns_enter(nsi, &nsc);
 632         realname = realpath(debugfile, NULL);
 633         if (realname && access(realname, R_OK))
 634                 zfree(&realname);
 635         nsinfo__mountns_exit(&nsc);
 636 out:
 637         free(debugfile);
 638         return realname;
 639 }
 640
 641 int build_id_cache__add_s(const char *sbuild_id, const char *name,
 642                           struct nsinfo *nsi, bool is_kallsyms, bool is_vdso)
 643 {
 644         const size_t size = PATH_MAX;
 645         char *realname = NULL, *filename = NULL, *dir_name = NULL,
 646              *linkname = zalloc(size), *tmp;
 647         char *debugfile = NULL;
 648         int err = -1;
 649
 650         if (!is_kallsyms) {
 651                 if (!is_vdso)
 652                         realname = nsinfo__realpath(name, nsi);
 653                 else
 654                         realname = realpath(name, NULL);
 655                 if (!realname)
 656                         goto out_free;
 657         }
 658
 659         dir_name = build_id_cache__cachedir(sbuild_id, name, nsi, is_kallsyms,
 660                                             is_vdso);
 661         if (!dir_name)
 662                 goto out_free;
 663
 664         /* Remove old style build-id cache */
 665         if (is_regular_file(dir_name))
 666                 if (unlink(dir_name))
 667                         goto out_free;
 668
 669         if (mkdir_p(dir_name, 0755))
 670                 goto out_free;
 671
 672         /* Save the allocated buildid dirname */
 673         if (asprintf(&filename, "%s/%s", dir_name,
 674                      build_id_cache__basename(is_kallsyms, is_vdso,
 675                      false)) < 0) {
 676                 filename = NULL;
 677                 goto out_free;
 678         }
 679
 680         if (access(filename, F_OK)) {
 681                 if (is_kallsyms) {
 682                         if (copyfile("/proc/kallsyms", filename))
 683                                 goto out_free;
 684                 } else if (nsi && nsi->need_setns) {
 685                         if (copyfile_ns(name, filename, nsi))
 686                                 goto out_free;
 687                 } else if (link(realname, filename) && errno != EEXIST &&
 688                                 copyfile(name, filename))
 689                         goto out_free;
 690         }
 691
 692         /* Some binaries are stripped, but have .debug files with their symbol
 693          * table.  Check to see if we can locate one of those, since the elf
 694          * file itself may not be very useful to users of our tools without a
 695          * symtab.
 696          */
 697         if (!is_kallsyms && !is_vdso &&
 698             strncmp(".ko", name + strlen(name) - 3, 3)) {
 699                 debugfile = build_id_cache__find_debug(sbuild_id, nsi);
 700                 if (debugfile) {
 701                         zfree(&filename);
 702                         if (asprintf(&filename, "%s/%s", dir_name,
 703                             build_id_cache__basename(false, false, true)) < 0) {
 704                                 filename = NULL;
 705                                 goto out_free;
 706                         }
 707                         if (access(filename, F_OK)) {
 708                                 if (nsi && nsi->need_setns) {
 709                                         if (copyfile_ns(debugfile, filename,
 710                                                         nsi))
 711                                                 goto out_free;
 712                                 } else if (link(debugfile, filename) &&
 713                                                 errno != EEXIST &&
 714                                                 copyfile(debugfile, filename))
 715                                         goto out_free;
 716                         }
 717                 }
 718         }
 719
 720         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 721                 goto out_free;
 722         tmp = strrchr(linkname, '/');
 723         *tmp = '\0';
 724
 725         if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
 726                 goto out_free;
 727
 728         *tmp = '/';
 729         tmp = dir_name + strlen(buildid_dir) - 5;
 730         memcpy(tmp, "../..", 5);
 731
 732         if (symlink(tmp, linkname) == 0)
 733                 err = 0;
 734
 735         /* Update SDT cache : error is just warned */
 736         if (realname &&
 737             build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) < 0)
 738                 pr_debug4("Failed to update/scan SDT cache for %s\n", realname);
 739
 740 out_free:
 741         if (!is_kallsyms)
 742                 free(realname);
 743         free(filename);
 744         free(debugfile);
 745         free(dir_name);
 746         free(linkname);
 747         return err;
 748 }
 749
 750 static int build_id_cache__add_b(const u8 *build_id, size_t build_id_size,
 751                                  const char *name, struct nsinfo *nsi,
 752                                  bool is_kallsyms, bool is_vdso)
 753 {
 754         char sbuild_id[SBUILD_ID_SIZE];
 755
 756         build_id__sprintf(build_id, build_id_size, sbuild_id);
 757
 758         return build_id_cache__add_s(sbuild_id, name, nsi, is_kallsyms,
 759                                      is_vdso);
 760 }
 761
 762 bool build_id_cache__cached(const char *sbuild_id)
 763 {
 764         bool ret = false;
 765         char *filename = build_id_cache__linkname(sbuild_id, NULL, 0);
 766
 767         if (filename && !access(filename, F_OK))
 768                 ret = true;
 769         free(filename);
 770
 771         return ret;
 772 }
 773
 774 int build_id_cache__remove_s(const char *sbuild_id)
 775 {
 776         const size_t size = PATH_MAX;
 777         char *filename = zalloc(size),
 778              *linkname = zalloc(size), *tmp;
 779         int err = -1;
 780
 781         if (filename == NULL || linkname == NULL)
 782                 goto out_free;
 783
 784         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 785                 goto out_free;
 786
 787         if (access(linkname, F_OK))
 788                 goto out_free;
 789
 790         if (readlink(linkname, filename, size - 1) < 0)
 791                 goto out_free;
 792
 793         if (unlink(linkname))
 794                 goto out_free;
 795
 796         /*
 797          * Since the link is relative, we must make it absolute:
 798          */
 799         tmp = strrchr(linkname, '/') + 1;
 800         snprintf(tmp, size - (tmp - linkname), "%s", filename);
 801
 802         if (rm_rf(linkname))
 803                 goto out_free;
 804
 805         err = 0;
 806 out_free:
 807         free(filename);
 808         free(linkname);
 809         return err;
 810 }
 811
 812 static int dso__cache_build_id(struct dso *dso, struct machine *machine)
 813 {
 814         bool is_kallsyms = dso__is_kallsyms(dso);
 815         bool is_vdso = dso__is_vdso(dso);
 816         const char *name = dso->long_name;
 817
 818         if (dso__is_kcore(dso)) {
 819                 is_kallsyms = true;
 820                 name = machine->mmap_name;
 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_cached(&session->machines.guests); nd;
 858              nd = rb_next(nd)) {
 859                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 860                 ret |= machine__cache_build_ids(pos);
 861         }
 862         return ret ? -1 : 0;
 863 }
 864
 865 static bool machine__read_build_ids(struct machine *machine, bool with_hits)
 866 {
 867         return __dsos__read_build_ids(&machine->dsos.head, with_hits);
 868 }
 869
 870 bool perf_session__read_build_ids(struct perf_session *session, bool with_hits)
 871 {
 872         struct rb_node *nd;
 873         bool ret = machine__read_build_ids(&session->machines.host, with_hits);
 874
 875         for (nd = rb_first_cached(&session->machines.guests); nd;
 876              nd = rb_next(nd)) {
 877                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 878                 ret |= machine__read_build_ids(pos, with_hits);
 879         }
 880
 881         return ret;
 882 }