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