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 "symbol.h"
  19 #include "thread.h"
  20 #include <linux/kernel.h>
  21 #include "debug.h"
  22 #include "session.h"
  23 #include "tool.h"
  24 #include "header.h"
  25 #include "vdso.h"
  26 #include "path.h"
  27 #include "probe-file.h"
  28 #include "strlist.h"
  29
  30 #include "sane_ctype.h"
  31
  32 static bool no_buildid_cache;
  33
  34 int build_id__mark_dso_hit(struct perf_tool *tool __maybe_unused,
  35                            union perf_event *event,
  36                            struct perf_sample *sample,
  37                            struct perf_evsel *evsel __maybe_unused,
  38                            struct machine *machine)
  39 {
  40         struct addr_location al;
  41         struct thread *thread = machine__findnew_thread(machine, sample->pid,
  42                                                         sample->tid);
  43
  44         if (thread == NULL) {
  45                 pr_err("problem processing %d event, skipping it.\n",
  46                         event->header.type);
  47                 return -1;
  48         }
  49
  50         thread__find_addr_map(thread, sample->cpumode, MAP__FUNCTION, sample->ip, &al);
  51
  52         if (al.map != NULL)
  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 char *build_id_cache__origname(const char *sbuild_id)
 189 {
 190         char *linkname;
 191         char buf[PATH_MAX];
 192         char *ret = NULL, *p;
 193         size_t offs = 5;        /* == strlen("../..") */
 194         ssize_t len;
 195
 196         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 197         if (!linkname)
 198                 return NULL;
 199
 200         len = readlink(linkname, buf, sizeof(buf) - 1);
 201         if (len <= 0)
 202                 goto out;
 203         buf[len] = '\0';
 204
 205         /* The link should be "../..<origpath>/<sbuild_id>" */
 206         p = strrchr(buf, '/');  /* Cut off the "/<sbuild_id>" */
 207         if (p && (p > buf + offs)) {
 208                 *p = '\0';
 209                 if (buf[offs + 1] == '[')
 210                         offs++; /*
 211                                  * This is a DSO name, like [kernel.kallsyms].
 212                                  * Skip the first '/', since this is not the
 213                                  * cache of a regular file.
 214                                  */
 215                 ret = strdup(buf + offs);       /* Skip "../..[/]" */
 216         }
 217 out:
 218         free(linkname);
 219         return ret;
 220 }
 221
 222 /* Check if the given build_id cache is valid on current running system */
 223 static bool build_id_cache__valid_id(char *sbuild_id)
 224 {
 225         char real_sbuild_id[SBUILD_ID_SIZE] = "";
 226         char *pathname;
 227         int ret = 0;
 228         bool result = false;
 229
 230         pathname = build_id_cache__origname(sbuild_id);
 231         if (!pathname)
 232                 return false;
 233
 234         if (!strcmp(pathname, DSO__NAME_KALLSYMS))
 235                 ret = sysfs__sprintf_build_id("/", real_sbuild_id);
 236         else if (pathname[0] == '/')
 237                 ret = filename__sprintf_build_id(pathname, real_sbuild_id);
 238         else
 239                 ret = -EINVAL;  /* Should we support other special DSO cache? */
 240         if (ret >= 0)
 241                 result = (strcmp(sbuild_id, real_sbuild_id) == 0);
 242         free(pathname);
 243
 244         return result;
 245 }
 246
 247 static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso,
 248                                             bool is_debug)
 249 {
 250         return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : (is_debug ?
 251             "debug" : "elf"));
 252 }
 253
 254 char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
 255                              bool is_debug)
 256 {
 257         bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
 258         bool is_vdso = dso__is_vdso((struct dso *)dso);
 259         char sbuild_id[SBUILD_ID_SIZE];
 260         char *linkname;
 261         bool alloc = (bf == NULL);
 262         int ret;
 263
 264         if (!dso->has_build_id)
 265                 return NULL;
 266
 267         build_id__sprintf(dso->build_id, sizeof(dso->build_id), sbuild_id);
 268         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 269         if (!linkname)
 270                 return NULL;
 271
 272         /* Check if old style build_id cache */
 273         if (is_regular_file(linkname))
 274                 ret = asnprintf(&bf, size, "%s", linkname);
 275         else
 276                 ret = asnprintf(&bf, size, "%s/%s", linkname,
 277                          build_id_cache__basename(is_kallsyms, is_vdso,
 278                                                   is_debug));
 279         if (ret < 0 || (!alloc && size < (unsigned int)ret))
 280                 bf = NULL;
 281         free(linkname);
 282
 283         return bf;
 284 }
 285
 286 #define dsos__for_each_with_build_id(pos, head) \
 287         list_for_each_entry(pos, head, node)    \
 288                 if (!pos->has_build_id)         \
 289                         continue;               \
 290                 else
 291
 292 static int write_buildid(const char *name, size_t name_len, u8 *build_id,
 293                          pid_t pid, u16 misc, struct feat_fd *fd)
 294 {
 295         int err;
 296         struct build_id_event b;
 297         size_t len;
 298
 299         len = name_len + 1;
 300         len = PERF_ALIGN(len, NAME_ALIGN);
 301
 302         memset(&b, 0, sizeof(b));
 303         memcpy(&b.build_id, build_id, BUILD_ID_SIZE);
 304         b.pid = pid;
 305         b.header.misc = misc;
 306         b.header.size = sizeof(b) + len;
 307
 308         err = do_write(fd, &b, sizeof(b));
 309         if (err < 0)
 310                 return err;
 311
 312         return write_padded(fd, name, name_len + 1, len);
 313 }
 314
 315 static int machine__write_buildid_table(struct machine *machine,
 316                                         struct feat_fd *fd)
 317 {
 318         int err = 0;
 319         char nm[PATH_MAX];
 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                         machine__mmap_name(machine, nm, sizeof(nm));
 342                         name = nm;
 343                         name_len = strlen(nm);
 344                 } else {
 345                         name = pos->long_name;
 346                         name_len = pos->long_name_len;
 347                 }
 348
 349                 in_kernel = pos->kernel ||
 350                                 is_kernel_module(name,
 351                                         PERF_RECORD_MISC_CPUMODE_UNKNOWN);
 352                 err = write_buildid(name, name_len, pos->build_id, machine->pid,
 353                                     in_kernel ? kmisc : umisc, fd);
 354                 if (err)
 355                         break;
 356         }
 357
 358         return err;
 359 }
 360
 361 int perf_session__write_buildid_table(struct perf_session *session,
 362                                       struct feat_fd *fd)
 363 {
 364         struct rb_node *nd;
 365         int err = machine__write_buildid_table(&session->machines.host, fd);
 366
 367         if (err)
 368                 return err;
 369
 370         for (nd = rb_first(&session->machines.guests); nd; 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(&session->machines.guests); nd; nd = rb_next(nd)) {
 404                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 405
 406                 err = machine__hit_all_dsos(pos);
 407                 if (err)
 408                         return err;
 409         }
 410
 411         return 0;
 412 }
 413
 414 void disable_buildid_cache(void)
 415 {
 416         no_buildid_cache = true;
 417 }
 418
 419 static bool lsdir_bid_head_filter(const char *name __maybe_unused,
 420                                   struct dirent *d)
 421 {
 422         return (strlen(d->d_name) == 2) &&
 423                 isxdigit(d->d_name[0]) && isxdigit(d->d_name[1]);
 424 }
 425
 426 static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
 427                                   struct dirent *d)
 428 {
 429         int i = 0;
 430         while (isxdigit(d->d_name[i]) && i < SBUILD_ID_SIZE - 3)
 431                 i++;
 432         return (i == SBUILD_ID_SIZE - 3) && (d->d_name[i] == '\0');
 433 }
 434
 435 struct strlist *build_id_cache__list_all(bool validonly)
 436 {
 437         struct strlist *toplist, *linklist = NULL, *bidlist;
 438         struct str_node *nd, *nd2;
 439         char *topdir, *linkdir = NULL;
 440         char sbuild_id[SBUILD_ID_SIZE];
 441
 442         /* for filename__ functions */
 443         if (validonly)
 444                 symbol__init(NULL);
 445
 446         /* Open the top-level directory */
 447         if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
 448                 return NULL;
 449
 450         bidlist = strlist__new(NULL, NULL);
 451         if (!bidlist)
 452                 goto out;
 453
 454         toplist = lsdir(topdir, lsdir_bid_head_filter);
 455         if (!toplist) {
 456                 pr_debug("Error in lsdir(%s): %d\n", topdir, errno);
 457                 /* If there is no buildid cache, return an empty list */
 458                 if (errno == ENOENT)
 459                         goto out;
 460                 goto err_out;
 461         }
 462
 463         strlist__for_each_entry(nd, toplist) {
 464                 if (asprintf(&linkdir, "%s/%s", topdir, nd->s) < 0)
 465                         goto err_out;
 466                 /* Open the lower-level directory */
 467                 linklist = lsdir(linkdir, lsdir_bid_tail_filter);
 468                 if (!linklist) {
 469                         pr_debug("Error in lsdir(%s): %d\n", linkdir, errno);
 470                         goto err_out;
 471                 }
 472                 strlist__for_each_entry(nd2, linklist) {
 473                         if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
 474                                      nd->s, nd2->s) != SBUILD_ID_SIZE - 1)
 475                                 goto err_out;
 476                         if (validonly && !build_id_cache__valid_id(sbuild_id))
 477                                 continue;
 478                         if (strlist__add(bidlist, sbuild_id) < 0)
 479                                 goto err_out;
 480                 }
 481                 strlist__delete(linklist);
 482                 zfree(&linkdir);
 483         }
 484
 485 out_free:
 486         strlist__delete(toplist);
 487 out:
 488         free(topdir);
 489
 490         return bidlist;
 491
 492 err_out:
 493         strlist__delete(linklist);
 494         zfree(&linkdir);
 495         strlist__delete(bidlist);
 496         bidlist = NULL;
 497         goto out_free;
 498 }
 499
 500 static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)
 501 {
 502         size_t i;
 503
 504         for (i = 0; i < len; i++) {
 505                 if (!isxdigit(maybe_sbuild_id[i]))
 506                         return false;
 507         }
 508         return true;
 509 }
 510
 511 /* Return the valid complete build-id */
 512 char *build_id_cache__complement(const char *incomplete_sbuild_id)
 513 {
 514         struct strlist *bidlist;
 515         struct str_node *nd, *cand = NULL;
 516         char *sbuild_id = NULL;
 517         size_t len = strlen(incomplete_sbuild_id);
 518
 519         if (len >= SBUILD_ID_SIZE ||
 520             !str_is_build_id(incomplete_sbuild_id, len))
 521                 return NULL;
 522
 523         bidlist = build_id_cache__list_all(true);
 524         if (!bidlist)
 525                 return NULL;
 526
 527         strlist__for_each_entry(nd, bidlist) {
 528                 if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)
 529                         continue;
 530                 if (cand) {     /* Error: There are more than 2 candidates. */
 531                         cand = NULL;
 532                         break;
 533                 }
 534                 cand = nd;
 535         }
 536         if (cand)
 537                 sbuild_id = strdup(cand->s);
 538         strlist__delete(bidlist);
 539
 540         return sbuild_id;
 541 }
 542
 543 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
 544                                struct nsinfo *nsi, bool is_kallsyms,
 545                                bool is_vdso)
 546 {
 547         char *realname = (char *)name, *filename;
 548         bool slash = is_kallsyms || is_vdso;
 549
 550         if (!slash) {
 551                 realname = nsinfo__realpath(name, nsi);
 552                 if (!realname)
 553                         return NULL;
 554         }
 555
 556         if (asprintf(&filename, "%s%s%s%s%s", buildid_dir, slash ? "/" : "",
 557                      is_vdso ? DSO__NAME_VDSO : realname,
 558                      sbuild_id ? "/" : "", sbuild_id ?: "") < 0)
 559                 filename = NULL;
 560
 561         if (!slash)
 562                 free(realname);
 563
 564         return filename;
 565 }
 566
 567 int build_id_cache__list_build_ids(const char *pathname, struct nsinfo *nsi,
 568                                    struct strlist **result)
 569 {
 570         char *dir_name;
 571         int ret = 0;
 572
 573         dir_name = build_id_cache__cachedir(NULL, pathname, nsi, false, false);
 574         if (!dir_name)
 575                 return -ENOMEM;
 576
 577         *result = lsdir(dir_name, lsdir_no_dot_filter);
 578         if (!*result)
 579                 ret = -errno;
 580         free(dir_name);
 581
 582         return ret;
 583 }
 584
 585 #if defined(HAVE_LIBELF_SUPPORT) && defined(HAVE_GELF_GETNOTE_SUPPORT)
 586 static int build_id_cache__add_sdt_cache(const char *sbuild_id,
 587                                           const char *realname,
 588                                           struct nsinfo *nsi)
 589 {
 590         struct probe_cache *cache;
 591         int ret;
 592         struct nscookie nsc;
 593
 594         cache = probe_cache__new(sbuild_id, nsi);
 595         if (!cache)
 596                 return -1;
 597
 598         nsinfo__mountns_enter(nsi, &nsc);
 599         ret = probe_cache__scan_sdt(cache, realname);
 600         nsinfo__mountns_exit(&nsc);
 601         if (ret >= 0) {
 602                 pr_debug4("Found %d SDTs in %s\n", ret, realname);
 603                 if (probe_cache__commit(cache) < 0)
 604                         ret = -1;
 605         }
 606         probe_cache__delete(cache);
 607         return ret;
 608 }
 609 #else
 610 #define build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) (0)
 611 #endif
 612
 613 static char *build_id_cache__find_debug(const char *sbuild_id,
 614                                         struct nsinfo *nsi)
 615 {
 616         char *realname = NULL;
 617         char *debugfile;
 618         struct nscookie nsc;
 619         size_t len = 0;
 620
 621         debugfile = calloc(1, PATH_MAX);
 622         if (!debugfile)
 623                 goto out;
 624
 625         len = __symbol__join_symfs(debugfile, PATH_MAX,
 626                                    "/usr/lib/debug/.build-id/");
 627         snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,
 628                  sbuild_id + 2);
 629
 630         nsinfo__mountns_enter(nsi, &nsc);
 631         realname = realpath(debugfile, NULL);
 632         if (realname && access(realname, R_OK))
 633                 zfree(&realname);
 634         nsinfo__mountns_exit(&nsc);
 635 out:
 636         free(debugfile);
 637         return realname;
 638 }
 639
 640 int build_id_cache__add_s(const char *sbuild_id, const char *name,
 641                           struct nsinfo *nsi, bool is_kallsyms, bool is_vdso)
 642 {
 643         const size_t size = PATH_MAX;
 644         char *realname = NULL, *filename = NULL, *dir_name = NULL,
 645              *linkname = zalloc(size), *tmp;
 646         char *debugfile = NULL;
 647         int err = -1;
 648
 649         if (!is_kallsyms) {
 650                 if (!is_vdso)
 651                         realname = nsinfo__realpath(name, nsi);
 652                 else
 653                         realname = realpath(name, NULL);
 654                 if (!realname)
 655                         goto out_free;
 656         }
 657
 658         dir_name = build_id_cache__cachedir(sbuild_id, name, nsi, is_kallsyms,
 659                                             is_vdso);
 660         if (!dir_name)
 661                 goto out_free;
 662
 663         /* Remove old style build-id cache */
 664         if (is_regular_file(dir_name))
 665                 if (unlink(dir_name))
 666                         goto out_free;
 667
 668         if (mkdir_p(dir_name, 0755))
 669                 goto out_free;
 670
 671         /* Save the allocated buildid dirname */
 672         if (asprintf(&filename, "%s/%s", dir_name,
 673                      build_id_cache__basename(is_kallsyms, is_vdso,
 674                      false)) < 0) {
 675                 filename = NULL;
 676                 goto out_free;
 677         }
 678
 679         if (access(filename, F_OK)) {
 680                 if (is_kallsyms) {
 681                         if (copyfile("/proc/kallsyms", filename))
 682                                 goto out_free;
 683                 } else if (nsi && nsi->need_setns) {
 684                         if (copyfile_ns(name, filename, nsi))
 685                                 goto out_free;
 686                 } else if (link(realname, filename) && errno != EEXIST &&
 687                                 copyfile(name, filename))
 688                         goto out_free;
 689         }
 690
 691         /* Some binaries are stripped, but have .debug files with their symbol
 692          * table.  Check to see if we can locate one of those, since the elf
 693          * file itself may not be very useful to users of our tools without a
 694          * symtab.
 695          */
 696         if (!is_kallsyms && !is_vdso &&
 697             strncmp(".ko", name + strlen(name) - 3, 3)) {
 698                 debugfile = build_id_cache__find_debug(sbuild_id, nsi);
 699                 if (debugfile) {
 700                         zfree(&filename);
 701                         if (asprintf(&filename, "%s/%s", dir_name,
 702                             build_id_cache__basename(false, false, true)) < 0) {
 703                                 filename = NULL;
 704                                 goto out_free;
 705                         }
 706                         if (access(filename, F_OK)) {
 707                                 if (nsi && nsi->need_setns) {
 708                                         if (copyfile_ns(debugfile, filename,
 709                                                         nsi))
 710                                                 goto out_free;
 711                                 } else if (link(debugfile, filename) &&
 712                                                 errno != EEXIST &&
 713                                                 copyfile(debugfile, filename))
 714                                         goto out_free;
 715                         }
 716                 }
 717         }
 718
 719         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 720                 goto out_free;
 721         tmp = strrchr(linkname, '/');
 722         *tmp = '\0';
 723
 724         if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
 725                 goto out_free;
 726
 727         *tmp = '/';
 728         tmp = dir_name + strlen(buildid_dir) - 5;
 729         memcpy(tmp, "../..", 5);
 730
 731         if (symlink(tmp, linkname) == 0)
 732                 err = 0;
 733
 734         /* Update SDT cache : error is just warned */
 735         if (realname &&
 736             build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) < 0)
 737                 pr_debug4("Failed to update/scan SDT cache for %s\n", realname);
 738
 739 out_free:
 740         if (!is_kallsyms)
 741                 free(realname);
 742         free(filename);
 743         free(debugfile);
 744         free(dir_name);
 745         free(linkname);
 746         return err;
 747 }
 748
 749 static int build_id_cache__add_b(const u8 *build_id, size_t build_id_size,
 750                                  const char *name, struct nsinfo *nsi,
 751                                  bool is_kallsyms, bool is_vdso)
 752 {
 753         char sbuild_id[SBUILD_ID_SIZE];
 754
 755         build_id__sprintf(build_id, build_id_size, sbuild_id);
 756
 757         return build_id_cache__add_s(sbuild_id, name, nsi, is_kallsyms,
 758                                      is_vdso);
 759 }
 760
 761 bool build_id_cache__cached(const char *sbuild_id)
 762 {
 763         bool ret = false;
 764         char *filename = build_id_cache__linkname(sbuild_id, NULL, 0);
 765
 766         if (filename && !access(filename, F_OK))
 767                 ret = true;
 768         free(filename);
 769
 770         return ret;
 771 }
 772
 773 int build_id_cache__remove_s(const char *sbuild_id)
 774 {
 775         const size_t size = PATH_MAX;
 776         char *filename = zalloc(size),
 777              *linkname = zalloc(size), *tmp;
 778         int err = -1;
 779
 780         if (filename == NULL || linkname == NULL)
 781                 goto out_free;
 782
 783         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 784                 goto out_free;
 785
 786         if (access(linkname, F_OK))
 787                 goto out_free;
 788
 789         if (readlink(linkname, filename, size - 1) < 0)
 790                 goto out_free;
 791
 792         if (unlink(linkname))
 793                 goto out_free;
 794
 795         /*
 796          * Since the link is relative, we must make it absolute:
 797          */
 798         tmp = strrchr(linkname, '/') + 1;
 799         snprintf(tmp, size - (tmp - linkname), "%s", filename);
 800
 801         if (rm_rf(linkname))
 802                 goto out_free;
 803
 804         err = 0;
 805 out_free:
 806         free(filename);
 807         free(linkname);
 808         return err;
 809 }
 810
 811 static int dso__cache_build_id(struct dso *dso, struct machine *machine)
 812 {
 813         bool is_kallsyms = dso__is_kallsyms(dso);
 814         bool is_vdso = dso__is_vdso(dso);
 815         const char *name = dso->long_name;
 816         char nm[PATH_MAX];
 817
 818         if (dso__is_kcore(dso)) {
 819                 is_kallsyms = true;
 820                 machine__mmap_name(machine, nm, sizeof(nm));
 821                 name = nm;
 822         }
 823         return build_id_cache__add_b(dso->build_id, sizeof(dso->build_id), name,
 824                                      dso->nsinfo, is_kallsyms, is_vdso);
 825 }
 826
 827 static int __dsos__cache_build_ids(struct list_head *head,
 828                                    struct machine *machine)
 829 {
 830         struct dso *pos;
 831         int err = 0;
 832
 833         dsos__for_each_with_build_id(pos, head)
 834                 if (dso__cache_build_id(pos, machine))
 835                         err = -1;
 836
 837         return err;
 838 }
 839
 840 static int machine__cache_build_ids(struct machine *machine)
 841 {
 842         return __dsos__cache_build_ids(&machine->dsos.head, machine);
 843 }
 844
 845 int perf_session__cache_build_ids(struct perf_session *session)
 846 {
 847         struct rb_node *nd;
 848         int ret;
 849
 850         if (no_buildid_cache)
 851                 return 0;
 852
 853         if (mkdir(buildid_dir, 0755) != 0 && errno != EEXIST)
 854                 return -1;
 855
 856         ret = machine__cache_build_ids(&session->machines.host);
 857
 858         for (nd = rb_first(&session->machines.guests); nd; 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(&session->machines.guests); nd; nd = rb_next(nd)) {
 876                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 877                 ret |= machine__read_build_ids(pos, with_hits);
 878         }
 879
 880         return ret;
 881 }