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" // lsdir(), mkdir_p(), rm_rf()
  11 #include <dirent.h>
  12 #include <errno.h>
  13 #include <stdio.h>
  14 #include <sys/stat.h>
  15 #include <sys/types.h>
  16 #include "util/copyfile.h"
  17 #include "dso.h"
  18 #include "build-id.h"
  19 #include "event.h"
  20 #include "namespaces.h"
  21 #include "map.h"
  22 #include "symbol.h"
  23 #include "thread.h"
  24 #include <linux/kernel.h>
  25 #include "debug.h"
  26 #include "session.h"
  27 #include "tool.h"
  28 #include "header.h"
  29 #include "vdso.h"
  30 #include "path.h"
  31 #include "probe-file.h"
  32 #include "strlist.h"
  33
  34 #ifdef HAVE_DEBUGINFOD_SUPPORT
  35 #include <elfutils/debuginfod.h>
  36 #endif
  37
  38 #include <linux/ctype.h>
  39 #include <linux/zalloc.h>
  40 #include <linux/string.h>
  41 #include <asm/bug.h>
  42
  43 static bool no_buildid_cache;
  44
  45 int build_id__mark_dso_hit(struct perf_tool *tool __maybe_unused,
  46                            union perf_event *event,
  47                            struct perf_sample *sample,
  48                            struct evsel *evsel __maybe_unused,
  49                            struct machine *machine)
  50 {
  51         struct addr_location al;
  52         struct thread *thread = machine__findnew_thread(machine, sample->pid,
  53                                                         sample->tid);
  54
  55         if (thread == NULL) {
  56                 pr_err("problem processing %d event, skipping it.\n",
  57                         event->header.type);
  58                 return -1;
  59         }
  60
  61         if (thread__find_map(thread, sample->cpumode, sample->ip, &al))
  62                 al.map->dso->hit = 1;
  63
  64         thread__put(thread);
  65         return 0;
  66 }
  67
  68 static int perf_event__exit_del_thread(struct perf_tool *tool __maybe_unused,
  69                                        union perf_event *event,
  70                                        struct perf_sample *sample
  71                                        __maybe_unused,
  72                                        struct machine *machine)
  73 {
  74         struct thread *thread = machine__findnew_thread(machine,
  75                                                         event->fork.pid,
  76                                                         event->fork.tid);
  77
  78         dump_printf("(%d:%d):(%d:%d)\n", event->fork.pid, event->fork.tid,
  79                     event->fork.ppid, event->fork.ptid);
  80
  81         if (thread) {
  82                 machine__remove_thread(machine, thread);
  83                 thread__put(thread);
  84         }
  85
  86         return 0;
  87 }
  88
  89 struct perf_tool build_id__mark_dso_hit_ops = {
  90         .sample = build_id__mark_dso_hit,
  91         .mmap   = perf_event__process_mmap,
  92         .mmap2  = perf_event__process_mmap2,
  93         .fork   = perf_event__process_fork,
  94         .exit   = perf_event__exit_del_thread,
  95         .attr            = perf_event__process_attr,
  96         .build_id        = perf_event__process_build_id,
  97         .ordered_events  = true,
  98 };
  99
 100 int build_id__sprintf(const struct build_id *build_id, char *bf)
 101 {
 102         char *bid = bf;
 103         const u8 *raw = build_id->data;
 104         size_t i;
 105
 106         bf[0] = 0x0;
 107
 108         for (i = 0; i < build_id->size; ++i) {
 109                 sprintf(bid, "%02x", *raw);
 110                 ++raw;
 111                 bid += 2;
 112         }
 113
 114         return (bid - bf) + 1;
 115 }
 116
 117 int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id)
 118 {
 119         char notes[PATH_MAX];
 120         struct build_id bid;
 121         int ret;
 122
 123         if (!root_dir)
 124                 root_dir = "";
 125
 126         scnprintf(notes, sizeof(notes), "%s/sys/kernel/notes", root_dir);
 127
 128         ret = sysfs__read_build_id(notes, &bid);
 129         if (ret < 0)
 130                 return ret;
 131
 132         return build_id__sprintf(&bid, sbuild_id);
 133 }
 134
 135 int filename__sprintf_build_id(const char *pathname, char *sbuild_id)
 136 {
 137         struct build_id bid;
 138         int ret;
 139
 140         ret = filename__read_build_id(pathname, &bid);
 141         if (ret < 0)
 142                 return ret;
 143
 144         return build_id__sprintf(&bid, sbuild_id);
 145 }
 146
 147 /* asnprintf consolidates asprintf and snprintf */
 148 static int asnprintf(char **strp, size_t size, const char *fmt, ...)
 149 {
 150         va_list ap;
 151         int ret;
 152
 153         if (!strp)
 154                 return -EINVAL;
 155
 156         va_start(ap, fmt);
 157         if (*strp)
 158                 ret = vsnprintf(*strp, size, fmt, ap);
 159         else
 160                 ret = vasprintf(strp, fmt, ap);
 161         va_end(ap);
 162
 163         return ret;
 164 }
 165
 166 char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
 167                                     size_t size)
 168 {
 169         bool retry_old = true;
 170
 171         snprintf(bf, size, "%s/%s/%s/kallsyms",
 172                  buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
 173 retry:
 174         if (!access(bf, F_OK))
 175                 return bf;
 176         if (retry_old) {
 177                 /* Try old style kallsyms cache */
 178                 snprintf(bf, size, "%s/%s/%s",
 179                          buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
 180                 retry_old = false;
 181                 goto retry;
 182         }
 183
 184         return NULL;
 185 }
 186
 187 char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size)
 188 {
 189         char *tmp = bf;
 190         int ret = asnprintf(&bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
 191                             sbuild_id, sbuild_id + 2);
 192         if (ret < 0 || (tmp && size < (unsigned int)ret))
 193                 return NULL;
 194         return bf;
 195 }
 196
 197 /* The caller is responsible to free the returned buffer. */
 198 char *build_id_cache__origname(const char *sbuild_id)
 199 {
 200         char *linkname;
 201         char buf[PATH_MAX];
 202         char *ret = NULL, *p;
 203         size_t offs = 5;        /* == strlen("../..") */
 204         ssize_t len;
 205
 206         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 207         if (!linkname)
 208                 return NULL;
 209
 210         len = readlink(linkname, buf, sizeof(buf) - 1);
 211         if (len <= 0)
 212                 goto out;
 213         buf[len] = '\0';
 214
 215         /* The link should be "../..<origpath>/<sbuild_id>" */
 216         p = strrchr(buf, '/');  /* Cut off the "/<sbuild_id>" */
 217         if (p && (p > buf + offs)) {
 218                 *p = '\0';
 219                 if (buf[offs + 1] == '[')
 220                         offs++; /*
 221                                  * This is a DSO name, like [kernel.kallsyms].
 222                                  * Skip the first '/', since this is not the
 223                                  * cache of a regular file.
 224                                  */
 225                 ret = strdup(buf + offs);       /* Skip "../..[/]" */
 226         }
 227 out:
 228         free(linkname);
 229         return ret;
 230 }
 231
 232 /* Check if the given build_id cache is valid on current running system */
 233 static bool build_id_cache__valid_id(char *sbuild_id)
 234 {
 235         char real_sbuild_id[SBUILD_ID_SIZE] = "";
 236         char *pathname;
 237         int ret = 0;
 238         bool result = false;
 239
 240         pathname = build_id_cache__origname(sbuild_id);
 241         if (!pathname)
 242                 return false;
 243
 244         if (!strcmp(pathname, DSO__NAME_KALLSYMS))
 245                 ret = sysfs__sprintf_build_id("/", real_sbuild_id);
 246         else if (pathname[0] == '/')
 247                 ret = filename__sprintf_build_id(pathname, real_sbuild_id);
 248         else
 249                 ret = -EINVAL;  /* Should we support other special DSO cache? */
 250         if (ret >= 0)
 251                 result = (strcmp(sbuild_id, real_sbuild_id) == 0);
 252         free(pathname);
 253
 254         return result;
 255 }
 256
 257 static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso,
 258                                             bool is_debug)
 259 {
 260         return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : (is_debug ?
 261             "debug" : "elf"));
 262 }
 263
 264 char *__dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
 265                                bool is_debug, bool is_kallsyms)
 266 {
 267         bool is_vdso = dso__is_vdso((struct dso *)dso);
 268         char sbuild_id[SBUILD_ID_SIZE];
 269         char *linkname;
 270         bool alloc = (bf == NULL);
 271         int ret;
 272
 273         if (!dso->has_build_id)
 274                 return NULL;
 275
 276         build_id__sprintf(&dso->bid, sbuild_id);
 277         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 278         if (!linkname)
 279                 return NULL;
 280
 281         /* Check if old style build_id cache */
 282         if (is_regular_file(linkname))
 283                 ret = asnprintf(&bf, size, "%s", linkname);
 284         else
 285                 ret = asnprintf(&bf, size, "%s/%s", linkname,
 286                          build_id_cache__basename(is_kallsyms, is_vdso,
 287                                                   is_debug));
 288         if (ret < 0 || (!alloc && size < (unsigned int)ret))
 289                 bf = NULL;
 290         free(linkname);
 291
 292         return bf;
 293 }
 294
 295 char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
 296                              bool is_debug)
 297 {
 298         bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
 299
 300         return __dso__build_id_filename(dso, bf, size, is_debug, is_kallsyms);
 301 }
 302
 303 #define dsos__for_each_with_build_id(pos, head) \
 304         list_for_each_entry(pos, head, node)    \
 305                 if (!pos->has_build_id)         \
 306                         continue;               \
 307                 else
 308
 309 static int write_buildid(const char *name, size_t name_len, struct build_id *bid,
 310                          pid_t pid, u16 misc, struct feat_fd *fd)
 311 {
 312         int err;
 313         struct perf_record_header_build_id b;
 314         size_t len;
 315
 316         len = name_len + 1;
 317         len = PERF_ALIGN(len, NAME_ALIGN);
 318
 319         memset(&b, 0, sizeof(b));
 320         memcpy(&b.data, bid->data, bid->size);
 321         b.size = (u8) bid->size;
 322         misc |= PERF_RECORD_MISC_BUILD_ID_SIZE;
 323         b.pid = pid;
 324         b.header.misc = misc;
 325         b.header.size = sizeof(b) + len;
 326
 327         err = do_write(fd, &b, sizeof(b));
 328         if (err < 0)
 329                 return err;
 330
 331         return write_padded(fd, name, name_len + 1, len);
 332 }
 333
 334 static int machine__write_buildid_table(struct machine *machine,
 335                                         struct feat_fd *fd)
 336 {
 337         int err = 0;
 338         struct dso *pos;
 339         u16 kmisc = PERF_RECORD_MISC_KERNEL,
 340             umisc = PERF_RECORD_MISC_USER;
 341
 342         if (!machine__is_host(machine)) {
 343                 kmisc = PERF_RECORD_MISC_GUEST_KERNEL;
 344                 umisc = PERF_RECORD_MISC_GUEST_USER;
 345         }
 346
 347         dsos__for_each_with_build_id(pos, &machine->dsos.head) {
 348                 const char *name;
 349                 size_t name_len;
 350                 bool in_kernel = false;
 351
 352                 if (!pos->hit && !dso__is_vdso(pos))
 353                         continue;
 354
 355                 if (dso__is_vdso(pos)) {
 356                         name = pos->short_name;
 357                         name_len = pos->short_name_len;
 358                 } else if (dso__is_kcore(pos)) {
 359                         name = machine->mmap_name;
 360                         name_len = strlen(name);
 361                 } else {
 362                         name = pos->long_name;
 363                         name_len = pos->long_name_len;
 364                 }
 365
 366                 in_kernel = pos->kernel ||
 367                                 is_kernel_module(name,
 368                                         PERF_RECORD_MISC_CPUMODE_UNKNOWN);
 369                 err = write_buildid(name, name_len, &pos->bid, machine->pid,
 370                                     in_kernel ? kmisc : umisc, fd);
 371                 if (err)
 372                         break;
 373         }
 374
 375         return err;
 376 }
 377
 378 int perf_session__write_buildid_table(struct perf_session *session,
 379                                       struct feat_fd *fd)
 380 {
 381         struct rb_node *nd;
 382         int err = machine__write_buildid_table(&session->machines.host, fd);
 383
 384         if (err)
 385                 return err;
 386
 387         for (nd = rb_first_cached(&session->machines.guests); nd;
 388              nd = rb_next(nd)) {
 389                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 390                 err = machine__write_buildid_table(pos, fd);
 391                 if (err)
 392                         break;
 393         }
 394         return err;
 395 }
 396
 397 static int __dsos__hit_all(struct list_head *head)
 398 {
 399         struct dso *pos;
 400
 401         list_for_each_entry(pos, head, node)
 402                 pos->hit = true;
 403
 404         return 0;
 405 }
 406
 407 static int machine__hit_all_dsos(struct machine *machine)
 408 {
 409         return __dsos__hit_all(&machine->dsos.head);
 410 }
 411
 412 int dsos__hit_all(struct perf_session *session)
 413 {
 414         struct rb_node *nd;
 415         int err;
 416
 417         err = machine__hit_all_dsos(&session->machines.host);
 418         if (err)
 419                 return err;
 420
 421         for (nd = rb_first_cached(&session->machines.guests); nd;
 422              nd = rb_next(nd)) {
 423                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 424
 425                 err = machine__hit_all_dsos(pos);
 426                 if (err)
 427                         return err;
 428         }
 429
 430         return 0;
 431 }
 432
 433 void disable_buildid_cache(void)
 434 {
 435         no_buildid_cache = true;
 436 }
 437
 438 static bool lsdir_bid_head_filter(const char *name __maybe_unused,
 439                                   struct dirent *d)
 440 {
 441         return (strlen(d->d_name) == 2) &&
 442                 isxdigit(d->d_name[0]) && isxdigit(d->d_name[1]);
 443 }
 444
 445 static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
 446                                   struct dirent *d)
 447 {
 448         int i = 0;
 449         while (isxdigit(d->d_name[i]) && i < SBUILD_ID_SIZE - 3)
 450                 i++;
 451         return (i == SBUILD_ID_SIZE - 3) && (d->d_name[i] == '\0');
 452 }
 453
 454 struct strlist *build_id_cache__list_all(bool validonly)
 455 {
 456         struct strlist *toplist, *linklist = NULL, *bidlist;
 457         struct str_node *nd, *nd2;
 458         char *topdir, *linkdir = NULL;
 459         char sbuild_id[SBUILD_ID_SIZE];
 460
 461         /* for filename__ functions */
 462         if (validonly)
 463                 symbol__init(NULL);
 464
 465         /* Open the top-level directory */
 466         if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
 467                 return NULL;
 468
 469         bidlist = strlist__new(NULL, NULL);
 470         if (!bidlist)
 471                 goto out;
 472
 473         toplist = lsdir(topdir, lsdir_bid_head_filter);
 474         if (!toplist) {
 475                 pr_debug("Error in lsdir(%s): %d\n", topdir, errno);
 476                 /* If there is no buildid cache, return an empty list */
 477                 if (errno == ENOENT)
 478                         goto out;
 479                 goto err_out;
 480         }
 481
 482         strlist__for_each_entry(nd, toplist) {
 483                 if (asprintf(&linkdir, "%s/%s", topdir, nd->s) < 0)
 484                         goto err_out;
 485                 /* Open the lower-level directory */
 486                 linklist = lsdir(linkdir, lsdir_bid_tail_filter);
 487                 if (!linklist) {
 488                         pr_debug("Error in lsdir(%s): %d\n", linkdir, errno);
 489                         goto err_out;
 490                 }
 491                 strlist__for_each_entry(nd2, linklist) {
 492                         if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
 493                                      nd->s, nd2->s) != SBUILD_ID_SIZE - 1)
 494                                 goto err_out;
 495                         if (validonly && !build_id_cache__valid_id(sbuild_id))
 496                                 continue;
 497                         if (strlist__add(bidlist, sbuild_id) < 0)
 498                                 goto err_out;
 499                 }
 500                 strlist__delete(linklist);
 501                 zfree(&linkdir);
 502         }
 503
 504 out_free:
 505         strlist__delete(toplist);
 506 out:
 507         free(topdir);
 508
 509         return bidlist;
 510
 511 err_out:
 512         strlist__delete(linklist);
 513         zfree(&linkdir);
 514         strlist__delete(bidlist);
 515         bidlist = NULL;
 516         goto out_free;
 517 }
 518
 519 static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)
 520 {
 521         size_t i;
 522
 523         for (i = 0; i < len; i++) {
 524                 if (!isxdigit(maybe_sbuild_id[i]))
 525                         return false;
 526         }
 527         return true;
 528 }
 529
 530 /* Return the valid complete build-id */
 531 char *build_id_cache__complement(const char *incomplete_sbuild_id)
 532 {
 533         struct strlist *bidlist;
 534         struct str_node *nd, *cand = NULL;
 535         char *sbuild_id = NULL;
 536         size_t len = strlen(incomplete_sbuild_id);
 537
 538         if (len >= SBUILD_ID_SIZE ||
 539             !str_is_build_id(incomplete_sbuild_id, len))
 540                 return NULL;
 541
 542         bidlist = build_id_cache__list_all(true);
 543         if (!bidlist)
 544                 return NULL;
 545
 546         strlist__for_each_entry(nd, bidlist) {
 547                 if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)
 548                         continue;
 549                 if (cand) {     /* Error: There are more than 2 candidates. */
 550                         cand = NULL;
 551                         break;
 552                 }
 553                 cand = nd;
 554         }
 555         if (cand)
 556                 sbuild_id = strdup(cand->s);
 557         strlist__delete(bidlist);
 558
 559         return sbuild_id;
 560 }
 561
 562 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
 563                                struct nsinfo *nsi, bool is_kallsyms,
 564                                bool is_vdso)
 565 {
 566         char *realname = (char *)name, *filename;
 567         bool slash = is_kallsyms || is_vdso;
 568
 569         if (!slash) {
 570                 realname = nsinfo__realpath(name, nsi);
 571                 if (!realname)
 572                         return NULL;
 573         }
 574
 575         if (asprintf(&filename, "%s%s%s%s%s", buildid_dir, slash ? "/" : "",
 576                      is_vdso ? DSO__NAME_VDSO : realname,
 577                      sbuild_id ? "/" : "", sbuild_id ?: "") < 0)
 578                 filename = NULL;
 579
 580         if (!slash)
 581                 free(realname);
 582
 583         return filename;
 584 }
 585
 586 int build_id_cache__list_build_ids(const char *pathname, struct nsinfo *nsi,
 587                                    struct strlist **result)
 588 {
 589         char *dir_name;
 590         int ret = 0;
 591
 592         dir_name = build_id_cache__cachedir(NULL, pathname, nsi, false, false);
 593         if (!dir_name)
 594                 return -ENOMEM;
 595
 596         *result = lsdir(dir_name, lsdir_no_dot_filter);
 597         if (!*result)
 598                 ret = -errno;
 599         free(dir_name);
 600
 601         return ret;
 602 }
 603
 604 #if defined(HAVE_LIBELF_SUPPORT) && defined(HAVE_GELF_GETNOTE_SUPPORT)
 605 static int build_id_cache__add_sdt_cache(const char *sbuild_id,
 606                                           const char *realname,
 607                                           struct nsinfo *nsi)
 608 {
 609         struct probe_cache *cache;
 610         int ret;
 611         struct nscookie nsc;
 612
 613         cache = probe_cache__new(sbuild_id, nsi);
 614         if (!cache)
 615                 return -1;
 616
 617         nsinfo__mountns_enter(nsi, &nsc);
 618         ret = probe_cache__scan_sdt(cache, realname);
 619         nsinfo__mountns_exit(&nsc);
 620         if (ret >= 0) {
 621                 pr_debug4("Found %d SDTs in %s\n", ret, realname);
 622                 if (probe_cache__commit(cache) < 0)
 623                         ret = -1;
 624         }
 625         probe_cache__delete(cache);
 626         return ret;
 627 }
 628 #else
 629 #define build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) (0)
 630 #endif
 631
 632 static char *build_id_cache__find_debug(const char *sbuild_id,
 633                                         struct nsinfo *nsi)
 634 {
 635         char *realname = NULL;
 636         char *debugfile;
 637         struct nscookie nsc;
 638         size_t len = 0;
 639
 640         debugfile = calloc(1, PATH_MAX);
 641         if (!debugfile)
 642                 goto out;
 643
 644         len = __symbol__join_symfs(debugfile, PATH_MAX,
 645                                    "/usr/lib/debug/.build-id/");
 646         snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,
 647                  sbuild_id + 2);
 648
 649         nsinfo__mountns_enter(nsi, &nsc);
 650         realname = realpath(debugfile, NULL);
 651         if (realname && access(realname, R_OK))
 652                 zfree(&realname);
 653         nsinfo__mountns_exit(&nsc);
 654
 655 #ifdef HAVE_DEBUGINFOD_SUPPORT
 656         if (realname == NULL) {
 657                 debuginfod_client* c = debuginfod_begin();
 658                 if (c != NULL) {
 659                         int fd = debuginfod_find_debuginfo(c,
 660                                                            (const unsigned char*)sbuild_id, 0,
 661                                                            &realname);
 662                         if (fd >= 0)
 663                                 close(fd); /* retaining reference by realname */
 664                         debuginfod_end(c);
 665                 }
 666         }
 667 #endif
 668
 669 out:
 670         free(debugfile);
 671         return realname;
 672 }
 673
 674 int
 675 build_id_cache__add(const char *sbuild_id, const char *name, const char *realname,
 676                     struct nsinfo *nsi, bool is_kallsyms, bool is_vdso)
 677 {
 678         const size_t size = PATH_MAX;
 679         char *filename = NULL, *dir_name = NULL, *linkname = zalloc(size), *tmp;
 680         char *debugfile = NULL;
 681         int err = -1;
 682
 683         dir_name = build_id_cache__cachedir(sbuild_id, name, nsi, is_kallsyms,
 684                                             is_vdso);
 685         if (!dir_name)
 686                 goto out_free;
 687
 688         /* Remove old style build-id cache */
 689         if (is_regular_file(dir_name))
 690                 if (unlink(dir_name))
 691                         goto out_free;
 692
 693         if (mkdir_p(dir_name, 0755))
 694                 goto out_free;
 695
 696         /* Save the allocated buildid dirname */
 697         if (asprintf(&filename, "%s/%s", dir_name,
 698                      build_id_cache__basename(is_kallsyms, is_vdso,
 699                      false)) < 0) {
 700                 filename = NULL;
 701                 goto out_free;
 702         }
 703
 704         if (access(filename, F_OK)) {
 705                 if (is_kallsyms) {
 706                         if (copyfile("/proc/kallsyms", filename))
 707                                 goto out_free;
 708                 } else if (nsi && nsi->need_setns) {
 709                         if (copyfile_ns(name, filename, nsi))
 710                                 goto out_free;
 711                 } else if (link(realname, filename) && errno != EEXIST &&
 712                                 copyfile(name, filename))
 713                         goto out_free;
 714         }
 715
 716         /* Some binaries are stripped, but have .debug files with their symbol
 717          * table.  Check to see if we can locate one of those, since the elf
 718          * file itself may not be very useful to users of our tools without a
 719          * symtab.
 720          */
 721         if (!is_kallsyms && !is_vdso &&
 722             strncmp(".ko", name + strlen(name) - 3, 3)) {
 723                 debugfile = build_id_cache__find_debug(sbuild_id, nsi);
 724                 if (debugfile) {
 725                         zfree(&filename);
 726                         if (asprintf(&filename, "%s/%s", dir_name,
 727                             build_id_cache__basename(false, false, true)) < 0) {
 728                                 filename = NULL;
 729                                 goto out_free;
 730                         }
 731                         if (access(filename, F_OK)) {
 732                                 if (nsi && nsi->need_setns) {
 733                                         if (copyfile_ns(debugfile, filename,
 734                                                         nsi))
 735                                                 goto out_free;
 736                                 } else if (link(debugfile, filename) &&
 737                                                 errno != EEXIST &&
 738                                                 copyfile(debugfile, filename))
 739                                         goto out_free;
 740                         }
 741                 }
 742         }
 743
 744         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 745                 goto out_free;
 746         tmp = strrchr(linkname, '/');
 747         *tmp = '\0';
 748
 749         if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
 750                 goto out_free;
 751
 752         *tmp = '/';
 753         tmp = dir_name + strlen(buildid_dir) - 5;
 754         memcpy(tmp, "../..", 5);
 755
 756         if (symlink(tmp, linkname) == 0) {
 757                 err = 0;
 758         } else if (errno == EEXIST) {
 759                 char path[PATH_MAX];
 760                 ssize_t len;
 761
 762                 len = readlink(linkname, path, sizeof(path) - 1);
 763                 if (len <= 0) {
 764                         pr_err("Cant read link: %s\n", linkname);
 765                         goto out_free;
 766                 }
 767                 path[len] = '\0';
 768
 769                 if (strcmp(tmp, path)) {
 770                         pr_debug("build <%s> already linked to %s\n",
 771                                  sbuild_id, linkname);
 772                 }
 773                 err = 0;
 774         }
 775
 776         /* Update SDT cache : error is just warned */
 777         if (realname &&
 778             build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) < 0)
 779                 pr_debug4("Failed to update/scan SDT cache for %s\n", realname);
 780
 781 out_free:
 782         free(filename);
 783         free(debugfile);
 784         free(dir_name);
 785         free(linkname);
 786         return err;
 787 }
 788
 789 int build_id_cache__add_s(const char *sbuild_id, const char *name,
 790                           struct nsinfo *nsi, bool is_kallsyms, bool is_vdso)
 791 {
 792         char *realname = NULL;
 793         int err = -1;
 794
 795         if (!is_kallsyms) {
 796                 if (!is_vdso)
 797                         realname = nsinfo__realpath(name, nsi);
 798                 else
 799                         realname = realpath(name, NULL);
 800                 if (!realname)
 801                         goto out_free;
 802         }
 803
 804         err = build_id_cache__add(sbuild_id, name, realname, nsi, is_kallsyms, is_vdso);
 805
 806 out_free:
 807         if (!is_kallsyms)
 808                 free(realname);
 809         return err;
 810 }
 811
 812 static int build_id_cache__add_b(const struct build_id *bid,
 813                                  const char *name, struct nsinfo *nsi,
 814                                  bool is_kallsyms, bool is_vdso)
 815 {
 816         char sbuild_id[SBUILD_ID_SIZE];
 817
 818         build_id__sprintf(bid, sbuild_id);
 819
 820         return build_id_cache__add_s(sbuild_id, name, nsi, is_kallsyms,
 821                                      is_vdso);
 822 }
 823
 824 bool build_id_cache__cached(const char *sbuild_id)
 825 {
 826         bool ret = false;
 827         char *filename = build_id_cache__linkname(sbuild_id, NULL, 0);
 828
 829         if (filename && !access(filename, F_OK))
 830                 ret = true;
 831         free(filename);
 832
 833         return ret;
 834 }
 835
 836 int build_id_cache__remove_s(const char *sbuild_id)
 837 {
 838         const size_t size = PATH_MAX;
 839         char *filename = zalloc(size),
 840              *linkname = zalloc(size), *tmp;
 841         int err = -1;
 842
 843         if (filename == NULL || linkname == NULL)
 844                 goto out_free;
 845
 846         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 847                 goto out_free;
 848
 849         if (access(linkname, F_OK))
 850                 goto out_free;
 851
 852         if (readlink(linkname, filename, size - 1) < 0)
 853                 goto out_free;
 854
 855         if (unlink(linkname))
 856                 goto out_free;
 857
 858         /*
 859          * Since the link is relative, we must make it absolute:
 860          */
 861         tmp = strrchr(linkname, '/') + 1;
 862         snprintf(tmp, size - (tmp - linkname), "%s", filename);
 863
 864         if (rm_rf(linkname))
 865                 goto out_free;
 866
 867         err = 0;
 868 out_free:
 869         free(filename);
 870         free(linkname);
 871         return err;
 872 }
 873
 874 static int dso__cache_build_id(struct dso *dso, struct machine *machine,
 875                                void *priv __maybe_unused)
 876 {
 877         bool is_kallsyms = dso__is_kallsyms(dso);
 878         bool is_vdso = dso__is_vdso(dso);
 879         const char *name = dso->long_name;
 880
 881         if (!dso->has_build_id)
 882                 return 0;
 883
 884         if (dso__is_kcore(dso)) {
 885                 is_kallsyms = true;
 886                 name = machine->mmap_name;
 887         }
 888         return build_id_cache__add_b(&dso->bid, name, dso->nsinfo,
 889                                      is_kallsyms, is_vdso);
 890 }
 891
 892 static int
 893 machines__for_each_dso(struct machines *machines, machine__dso_t fn, void *priv)
 894 {
 895         int ret = machine__for_each_dso(&machines->host, fn, priv);
 896         struct rb_node *nd;
 897
 898         for (nd = rb_first_cached(&machines->guests); nd;
 899              nd = rb_next(nd)) {
 900                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 901
 902                 ret |= machine__for_each_dso(pos, fn, priv);
 903         }
 904         return ret ? -1 : 0;
 905 }
 906
 907 int __perf_session__cache_build_ids(struct perf_session *session,
 908                                     machine__dso_t fn, void *priv)
 909 {
 910         if (no_buildid_cache)
 911                 return 0;
 912
 913         if (mkdir(buildid_dir, 0755) != 0 && errno != EEXIST)
 914                 return -1;
 915
 916         return machines__for_each_dso(&session->machines, fn, priv) ?  -1 : 0;
 917 }
 918
 919 int perf_session__cache_build_ids(struct perf_session *session)
 920 {
 921         return __perf_session__cache_build_ids(session, dso__cache_build_id, NULL);
 922 }
 923
 924 static bool machine__read_build_ids(struct machine *machine, bool with_hits)
 925 {
 926         return __dsos__read_build_ids(&machine->dsos.head, with_hits);
 927 }
 928
 929 bool perf_session__read_build_ids(struct perf_session *session, bool with_hits)
 930 {
 931         struct rb_node *nd;
 932         bool ret = machine__read_build_ids(&session->machines.host, with_hits);
 933
 934         for (nd = rb_first_cached(&session->machines.guests); nd;
 935              nd = rb_next(nd)) {
 936                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 937                 ret |= machine__read_build_ids(pos, with_hits);
 938         }
 939
 940         return ret;
 941 }
 942
 943 void build_id__init(struct build_id *bid, const u8 *data, size_t size)
 944 {
 945         WARN_ON(size > BUILD_ID_SIZE);
 946         memcpy(bid->data, data, size);
 947         bid->size = size;
 948 }
 949
 950 bool build_id__is_defined(const struct build_id *bid)
 951 {
 952         return bid && bid->size ? !!memchr_inv(bid->data, 0, bid->size) : false;
 953 }