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_MIN_SIZE - 3) && (i <= SBUILD_ID_SIZE - 3) &&
 452                 (d->d_name[i] == '\0');
 453 }
 454
 455 struct strlist *build_id_cache__list_all(bool validonly)
 456 {
 457         struct strlist *toplist, *linklist = NULL, *bidlist;
 458         struct str_node *nd, *nd2;
 459         char *topdir, *linkdir = NULL;
 460         char sbuild_id[SBUILD_ID_SIZE];
 461
 462         /* for filename__ functions */
 463         if (validonly)
 464                 symbol__init(NULL);
 465
 466         /* Open the top-level directory */
 467         if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
 468                 return NULL;
 469
 470         bidlist = strlist__new(NULL, NULL);
 471         if (!bidlist)
 472                 goto out;
 473
 474         toplist = lsdir(topdir, lsdir_bid_head_filter);
 475         if (!toplist) {
 476                 pr_debug("Error in lsdir(%s): %d\n", topdir, errno);
 477                 /* If there is no buildid cache, return an empty list */
 478                 if (errno == ENOENT)
 479                         goto out;
 480                 goto err_out;
 481         }
 482
 483         strlist__for_each_entry(nd, toplist) {
 484                 if (asprintf(&linkdir, "%s/%s", topdir, nd->s) < 0)
 485                         goto err_out;
 486                 /* Open the lower-level directory */
 487                 linklist = lsdir(linkdir, lsdir_bid_tail_filter);
 488                 if (!linklist) {
 489                         pr_debug("Error in lsdir(%s): %d\n", linkdir, errno);
 490                         goto err_out;
 491                 }
 492                 strlist__for_each_entry(nd2, linklist) {
 493                         if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
 494                                      nd->s, nd2->s) > SBUILD_ID_SIZE - 1)
 495                                 goto err_out;
 496                         if (validonly && !build_id_cache__valid_id(sbuild_id))
 497                                 continue;
 498                         if (strlist__add(bidlist, sbuild_id) < 0)
 499                                 goto err_out;
 500                 }
 501                 strlist__delete(linklist);
 502                 zfree(&linkdir);
 503         }
 504
 505 out_free:
 506         strlist__delete(toplist);
 507 out:
 508         free(topdir);
 509
 510         return bidlist;
 511
 512 err_out:
 513         strlist__delete(linklist);
 514         zfree(&linkdir);
 515         strlist__delete(bidlist);
 516         bidlist = NULL;
 517         goto out_free;
 518 }
 519
 520 static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)
 521 {
 522         size_t i;
 523
 524         for (i = 0; i < len; i++) {
 525                 if (!isxdigit(maybe_sbuild_id[i]))
 526                         return false;
 527         }
 528         return true;
 529 }
 530
 531 /* Return the valid complete build-id */
 532 char *build_id_cache__complement(const char *incomplete_sbuild_id)
 533 {
 534         struct strlist *bidlist;
 535         struct str_node *nd, *cand = NULL;
 536         char *sbuild_id = NULL;
 537         size_t len = strlen(incomplete_sbuild_id);
 538
 539         if (len >= SBUILD_ID_SIZE ||
 540             !str_is_build_id(incomplete_sbuild_id, len))
 541                 return NULL;
 542
 543         bidlist = build_id_cache__list_all(true);
 544         if (!bidlist)
 545                 return NULL;
 546
 547         strlist__for_each_entry(nd, bidlist) {
 548                 if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)
 549                         continue;
 550                 if (cand) {     /* Error: There are more than 2 candidates. */
 551                         cand = NULL;
 552                         break;
 553                 }
 554                 cand = nd;
 555         }
 556         if (cand)
 557                 sbuild_id = strdup(cand->s);
 558         strlist__delete(bidlist);
 559
 560         return sbuild_id;
 561 }
 562
 563 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
 564                                struct nsinfo *nsi, bool is_kallsyms,
 565                                bool is_vdso)
 566 {
 567         char *realname = (char *)name, *filename;
 568         bool slash = is_kallsyms || is_vdso;
 569
 570         if (!slash) {
 571                 realname = nsinfo__realpath(name, nsi);
 572                 if (!realname)
 573                         return NULL;
 574         }
 575
 576         if (asprintf(&filename, "%s%s%s%s%s", buildid_dir, slash ? "/" : "",
 577                      is_vdso ? DSO__NAME_VDSO : realname,
 578                      sbuild_id ? "/" : "", sbuild_id ?: "") < 0)
 579                 filename = NULL;
 580
 581         if (!slash)
 582                 free(realname);
 583
 584         return filename;
 585 }
 586
 587 int build_id_cache__list_build_ids(const char *pathname, struct nsinfo *nsi,
 588                                    struct strlist **result)
 589 {
 590         char *dir_name;
 591         int ret = 0;
 592
 593         dir_name = build_id_cache__cachedir(NULL, pathname, nsi, false, false);
 594         if (!dir_name)
 595                 return -ENOMEM;
 596
 597         *result = lsdir(dir_name, lsdir_no_dot_filter);
 598         if (!*result)
 599                 ret = -errno;
 600         free(dir_name);
 601
 602         return ret;
 603 }
 604
 605 #if defined(HAVE_LIBELF_SUPPORT) && defined(HAVE_GELF_GETNOTE_SUPPORT)
 606 static int build_id_cache__add_sdt_cache(const char *sbuild_id,
 607                                           const char *realname,
 608                                           struct nsinfo *nsi)
 609 {
 610         struct probe_cache *cache;
 611         int ret;
 612         struct nscookie nsc;
 613
 614         cache = probe_cache__new(sbuild_id, nsi);
 615         if (!cache)
 616                 return -1;
 617
 618         nsinfo__mountns_enter(nsi, &nsc);
 619         ret = probe_cache__scan_sdt(cache, realname);
 620         nsinfo__mountns_exit(&nsc);
 621         if (ret >= 0) {
 622                 pr_debug4("Found %d SDTs in %s\n", ret, realname);
 623                 if (probe_cache__commit(cache) < 0)
 624                         ret = -1;
 625         }
 626         probe_cache__delete(cache);
 627         return ret;
 628 }
 629 #else
 630 #define build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) (0)
 631 #endif
 632
 633 static char *build_id_cache__find_debug(const char *sbuild_id,
 634                                         struct nsinfo *nsi)
 635 {
 636         char *realname = NULL;
 637         char *debugfile;
 638         struct nscookie nsc;
 639         size_t len = 0;
 640
 641         debugfile = calloc(1, PATH_MAX);
 642         if (!debugfile)
 643                 goto out;
 644
 645         len = __symbol__join_symfs(debugfile, PATH_MAX,
 646                                    "/usr/lib/debug/.build-id/");
 647         snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,
 648                  sbuild_id + 2);
 649
 650         nsinfo__mountns_enter(nsi, &nsc);
 651         realname = realpath(debugfile, NULL);
 652         if (realname && access(realname, R_OK))
 653                 zfree(&realname);
 654         nsinfo__mountns_exit(&nsc);
 655
 656 #ifdef HAVE_DEBUGINFOD_SUPPORT
 657         if (realname == NULL) {
 658                 debuginfod_client* c = debuginfod_begin();
 659                 if (c != NULL) {
 660                         int fd = debuginfod_find_debuginfo(c,
 661                                                            (const unsigned char*)sbuild_id, 0,
 662                                                            &realname);
 663                         if (fd >= 0)
 664                                 close(fd); /* retaining reference by realname */
 665                         debuginfod_end(c);
 666                 }
 667         }
 668 #endif
 669
 670 out:
 671         free(debugfile);
 672         return realname;
 673 }
 674
 675 int
 676 build_id_cache__add(const char *sbuild_id, const char *name, const char *realname,
 677                     struct nsinfo *nsi, bool is_kallsyms, bool is_vdso)
 678 {
 679         const size_t size = PATH_MAX;
 680         char *filename = NULL, *dir_name = NULL, *linkname = zalloc(size), *tmp;
 681         char *debugfile = NULL;
 682         int err = -1;
 683
 684         dir_name = build_id_cache__cachedir(sbuild_id, name, nsi, is_kallsyms,
 685                                             is_vdso);
 686         if (!dir_name)
 687                 goto out_free;
 688
 689         /* Remove old style build-id cache */
 690         if (is_regular_file(dir_name))
 691                 if (unlink(dir_name))
 692                         goto out_free;
 693
 694         if (mkdir_p(dir_name, 0755))
 695                 goto out_free;
 696
 697         /* Save the allocated buildid dirname */
 698         if (asprintf(&filename, "%s/%s", dir_name,
 699                      build_id_cache__basename(is_kallsyms, is_vdso,
 700                      false)) < 0) {
 701                 filename = NULL;
 702                 goto out_free;
 703         }
 704
 705         if (access(filename, F_OK)) {
 706                 if (is_kallsyms) {
 707                         if (copyfile("/proc/kallsyms", filename))
 708                                 goto out_free;
 709                 } else if (nsi && nsi->need_setns) {
 710                         if (copyfile_ns(name, filename, nsi))
 711                                 goto out_free;
 712                 } else if (link(realname, filename) && errno != EEXIST &&
 713                                 copyfile(name, filename))
 714                         goto out_free;
 715         }
 716
 717         /* Some binaries are stripped, but have .debug files with their symbol
 718          * table.  Check to see if we can locate one of those, since the elf
 719          * file itself may not be very useful to users of our tools without a
 720          * symtab.
 721          */
 722         if (!is_kallsyms && !is_vdso &&
 723             strncmp(".ko", name + strlen(name) - 3, 3)) {
 724                 debugfile = build_id_cache__find_debug(sbuild_id, nsi);
 725                 if (debugfile) {
 726                         zfree(&filename);
 727                         if (asprintf(&filename, "%s/%s", dir_name,
 728                             build_id_cache__basename(false, false, true)) < 0) {
 729                                 filename = NULL;
 730                                 goto out_free;
 731                         }
 732                         if (access(filename, F_OK)) {
 733                                 if (nsi && nsi->need_setns) {
 734                                         if (copyfile_ns(debugfile, filename,
 735                                                         nsi))
 736                                                 goto out_free;
 737                                 } else if (link(debugfile, filename) &&
 738                                                 errno != EEXIST &&
 739                                                 copyfile(debugfile, filename))
 740                                         goto out_free;
 741                         }
 742                 }
 743         }
 744
 745         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 746                 goto out_free;
 747         tmp = strrchr(linkname, '/');
 748         *tmp = '\0';
 749
 750         if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
 751                 goto out_free;
 752
 753         *tmp = '/';
 754         tmp = dir_name + strlen(buildid_dir) - 5;
 755         memcpy(tmp, "../..", 5);
 756
 757         if (symlink(tmp, linkname) == 0) {
 758                 err = 0;
 759         } else if (errno == EEXIST) {
 760                 char path[PATH_MAX];
 761                 ssize_t len;
 762
 763                 len = readlink(linkname, path, sizeof(path) - 1);
 764                 if (len <= 0) {
 765                         pr_err("Cant read link: %s\n", linkname);
 766                         goto out_free;
 767                 }
 768                 path[len] = '\0';
 769
 770                 if (strcmp(tmp, path)) {
 771                         pr_debug("build <%s> already linked to %s\n",
 772                                  sbuild_id, linkname);
 773                 }
 774                 err = 0;
 775         }
 776
 777         /* Update SDT cache : error is just warned */
 778         if (realname &&
 779             build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) < 0)
 780                 pr_debug4("Failed to update/scan SDT cache for %s\n", realname);
 781
 782 out_free:
 783         free(filename);
 784         free(debugfile);
 785         free(dir_name);
 786         free(linkname);
 787         return err;
 788 }
 789
 790 int build_id_cache__add_s(const char *sbuild_id, const char *name,
 791                           struct nsinfo *nsi, bool is_kallsyms, bool is_vdso)
 792 {
 793         char *realname = NULL;
 794         int err = -1;
 795
 796         if (!is_kallsyms) {
 797                 if (!is_vdso)
 798                         realname = nsinfo__realpath(name, nsi);
 799                 else
 800                         realname = realpath(name, NULL);
 801                 if (!realname)
 802                         goto out_free;
 803         }
 804
 805         err = build_id_cache__add(sbuild_id, name, realname, nsi, is_kallsyms, is_vdso);
 806
 807 out_free:
 808         if (!is_kallsyms)
 809                 free(realname);
 810         return err;
 811 }
 812
 813 static int build_id_cache__add_b(const struct build_id *bid,
 814                                  const char *name, struct nsinfo *nsi,
 815                                  bool is_kallsyms, bool is_vdso)
 816 {
 817         char sbuild_id[SBUILD_ID_SIZE];
 818
 819         build_id__sprintf(bid, sbuild_id);
 820
 821         return build_id_cache__add_s(sbuild_id, name, nsi, is_kallsyms,
 822                                      is_vdso);
 823 }
 824
 825 bool build_id_cache__cached(const char *sbuild_id)
 826 {
 827         bool ret = false;
 828         char *filename = build_id_cache__linkname(sbuild_id, NULL, 0);
 829
 830         if (filename && !access(filename, F_OK))
 831                 ret = true;
 832         free(filename);
 833
 834         return ret;
 835 }
 836
 837 int build_id_cache__remove_s(const char *sbuild_id)
 838 {
 839         const size_t size = PATH_MAX;
 840         char *filename = zalloc(size),
 841              *linkname = zalloc(size), *tmp;
 842         int err = -1;
 843
 844         if (filename == NULL || linkname == NULL)
 845                 goto out_free;
 846
 847         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 848                 goto out_free;
 849
 850         if (access(linkname, F_OK))
 851                 goto out_free;
 852
 853         if (readlink(linkname, filename, size - 1) < 0)
 854                 goto out_free;
 855
 856         if (unlink(linkname))
 857                 goto out_free;
 858
 859         /*
 860          * Since the link is relative, we must make it absolute:
 861          */
 862         tmp = strrchr(linkname, '/') + 1;
 863         snprintf(tmp, size - (tmp - linkname), "%s", filename);
 864
 865         if (rm_rf(linkname))
 866                 goto out_free;
 867
 868         err = 0;
 869 out_free:
 870         free(filename);
 871         free(linkname);
 872         return err;
 873 }
 874
 875 static int dso__cache_build_id(struct dso *dso, struct machine *machine,
 876                                void *priv __maybe_unused)
 877 {
 878         bool is_kallsyms = dso__is_kallsyms(dso);
 879         bool is_vdso = dso__is_vdso(dso);
 880         const char *name = dso->long_name;
 881
 882         if (!dso->has_build_id)
 883                 return 0;
 884
 885         if (dso__is_kcore(dso)) {
 886                 is_kallsyms = true;
 887                 name = machine->mmap_name;
 888         }
 889         return build_id_cache__add_b(&dso->bid, name, dso->nsinfo,
 890                                      is_kallsyms, is_vdso);
 891 }
 892
 893 static int
 894 machines__for_each_dso(struct machines *machines, machine__dso_t fn, void *priv)
 895 {
 896         int ret = machine__for_each_dso(&machines->host, fn, priv);
 897         struct rb_node *nd;
 898
 899         for (nd = rb_first_cached(&machines->guests); nd;
 900              nd = rb_next(nd)) {
 901                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 902
 903                 ret |= machine__for_each_dso(pos, fn, priv);
 904         }
 905         return ret ? -1 : 0;
 906 }
 907
 908 int __perf_session__cache_build_ids(struct perf_session *session,
 909                                     machine__dso_t fn, void *priv)
 910 {
 911         if (no_buildid_cache)
 912                 return 0;
 913
 914         if (mkdir(buildid_dir, 0755) != 0 && errno != EEXIST)
 915                 return -1;
 916
 917         return machines__for_each_dso(&session->machines, fn, priv) ?  -1 : 0;
 918 }
 919
 920 int perf_session__cache_build_ids(struct perf_session *session)
 921 {
 922         return __perf_session__cache_build_ids(session, dso__cache_build_id, NULL);
 923 }
 924
 925 static bool machine__read_build_ids(struct machine *machine, bool with_hits)
 926 {
 927         return __dsos__read_build_ids(&machine->dsos.head, with_hits);
 928 }
 929
 930 bool perf_session__read_build_ids(struct perf_session *session, bool with_hits)
 931 {
 932         struct rb_node *nd;
 933         bool ret = machine__read_build_ids(&session->machines.host, with_hits);
 934
 935         for (nd = rb_first_cached(&session->machines.guests); nd;
 936              nd = rb_next(nd)) {
 937                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 938                 ret |= machine__read_build_ids(pos, with_hits);
 939         }
 940
 941         return ret;
 942 }
 943
 944 void build_id__init(struct build_id *bid, const u8 *data, size_t size)
 945 {
 946         WARN_ON(size > BUILD_ID_SIZE);
 947         memcpy(bid->data, data, size);
 948         bid->size = size;
 949 }
 950
 951 bool build_id__is_defined(const struct build_id *bid)
 952 {
 953         return bid && bid->size ? !!memchr_inv(bid->data, 0, bid->size) : false;
 954 }