tools/perf/util/build-id.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * build-id.c
   4  *
   5  * build-id support
   6  *
   7  * Copyright (C) 2009, 2010 Red Hat Inc.
   8  * Copyright (C) 2009, 2010 Arnaldo Carvalho de Melo <acme@redhat.com>
   9  */
  10 #include "util.h"
  11 #include <dirent.h>
  12 #include <errno.h>
  13 #include <stdio.h>
  14 #include <sys/stat.h>
  15 #include <sys/types.h>
  16 #include "build-id.h"
  17 #include "event.h"
  18 #include "namespaces.h"
  19 #include "map.h"
  20 #include "symbol.h"
  21 #include "thread.h"
  22 #include <linux/kernel.h>
  23 #include "debug.h"
  24 #include "session.h"
  25 #include "tool.h"
  26 #include "header.h"
  27 #include "vdso.h"
  28 #include "path.h"
  29 #include "probe-file.h"
  30 #include "strlist.h"
  31
  32 #include <linux/ctype.h>
  33 #include <linux/zalloc.h>
  34
  35 static bool no_buildid_cache;
  36
  37 int build_id__mark_dso_hit(struct perf_tool *tool __maybe_unused,
  38                            union perf_event *event,
  39                            struct perf_sample *sample,
  40                            struct evsel *evsel __maybe_unused,
  41                            struct machine *machine)
  42 {
  43         struct addr_location al;
  44         struct thread *thread = machine__findnew_thread(machine, sample->pid,
  45                                                         sample->tid);
  46
  47         if (thread == NULL) {
  48                 pr_err("problem processing %d event, skipping it.\n",
  49                         event->header.type);
  50                 return -1;
  51         }
  52
  53         if (thread__find_map(thread, sample->cpumode, sample->ip, &al))
  54                 al.map->dso->hit = 1;
  55
  56         thread__put(thread);
  57         return 0;
  58 }
  59
  60 static int perf_event__exit_del_thread(struct perf_tool *tool __maybe_unused,
  61                                        union perf_event *event,
  62                                        struct perf_sample *sample
  63                                        __maybe_unused,
  64                                        struct machine *machine)
  65 {
  66         struct thread *thread = machine__findnew_thread(machine,
  67                                                         event->fork.pid,
  68                                                         event->fork.tid);
  69
  70         dump_printf("(%d:%d):(%d:%d)\n", event->fork.pid, event->fork.tid,
  71                     event->fork.ppid, event->fork.ptid);
  72
  73         if (thread) {
  74                 machine__remove_thread(machine, thread);
  75                 thread__put(thread);
  76         }
  77
  78         return 0;
  79 }
  80
  81 struct perf_tool build_id__mark_dso_hit_ops = {
  82         .sample = build_id__mark_dso_hit,
  83         .mmap   = perf_event__process_mmap,
  84         .mmap2  = perf_event__process_mmap2,
  85         .fork   = perf_event__process_fork,
  86         .exit   = perf_event__exit_del_thread,
  87         .attr            = perf_event__process_attr,
  88         .build_id        = perf_event__process_build_id,
  89         .ordered_events  = true,
  90 };
  91
  92 int build_id__sprintf(const u8 *build_id, int len, char *bf)
  93 {
  94         char *bid = bf;
  95         const u8 *raw = build_id;
  96         int i;
  97
  98         for (i = 0; i < len; ++i) {
  99                 sprintf(bid, "%02x", *raw);
 100                 ++raw;
 101                 bid += 2;
 102         }
 103
 104         return (bid - bf) + 1;
 105 }
 106
 107 int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id)
 108 {
 109         char notes[PATH_MAX];
 110         u8 build_id[BUILD_ID_SIZE];
 111         int ret;
 112
 113         if (!root_dir)
 114                 root_dir = "";
 115
 116         scnprintf(notes, sizeof(notes), "%s/sys/kernel/notes", root_dir);
 117
 118         ret = sysfs__read_build_id(notes, build_id, sizeof(build_id));
 119         if (ret < 0)
 120                 return ret;
 121
 122         return build_id__sprintf(build_id, sizeof(build_id), sbuild_id);
 123 }
 124
 125 int filename__sprintf_build_id(const char *pathname, char *sbuild_id)
 126 {
 127         u8 build_id[BUILD_ID_SIZE];
 128         int ret;
 129
 130         ret = filename__read_build_id(pathname, build_id, sizeof(build_id));
 131         if (ret < 0)
 132                 return ret;
 133         else if (ret != sizeof(build_id))
 134                 return -EINVAL;
 135
 136         return build_id__sprintf(build_id, sizeof(build_id), sbuild_id);
 137 }
 138
 139 /* asnprintf consolidates asprintf and snprintf */
 140 static int asnprintf(char **strp, size_t size, const char *fmt, ...)
 141 {
 142         va_list ap;
 143         int ret;
 144
 145         if (!strp)
 146                 return -EINVAL;
 147
 148         va_start(ap, fmt);
 149         if (*strp)
 150                 ret = vsnprintf(*strp, size, fmt, ap);
 151         else
 152                 ret = vasprintf(strp, fmt, ap);
 153         va_end(ap);
 154
 155         return ret;
 156 }
 157
 158 char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
 159                                     size_t size)
 160 {
 161         bool retry_old = true;
 162
 163         snprintf(bf, size, "%s/%s/%s/kallsyms",
 164                  buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
 165 retry:
 166         if (!access(bf, F_OK))
 167                 return bf;
 168         if (retry_old) {
 169                 /* Try old style kallsyms cache */
 170                 snprintf(bf, size, "%s/%s/%s",
 171                          buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
 172                 retry_old = false;
 173                 goto retry;
 174         }
 175
 176         return NULL;
 177 }
 178
 179 char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size)
 180 {
 181         char *tmp = bf;
 182         int ret = asnprintf(&bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
 183                             sbuild_id, sbuild_id + 2);
 184         if (ret < 0 || (tmp && size < (unsigned int)ret))
 185                 return NULL;
 186         return bf;
 187 }
 188
 189 /* The caller is responsible to free the returned buffer. */
 190 char *build_id_cache__origname(const char *sbuild_id)
 191 {
 192         char *linkname;
 193         char buf[PATH_MAX];
 194         char *ret = NULL, *p;
 195         size_t offs = 5;        /* == strlen("../..") */
 196         ssize_t len;
 197
 198         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 199         if (!linkname)
 200                 return NULL;
 201
 202         len = readlink(linkname, buf, sizeof(buf) - 1);
 203         if (len <= 0)
 204                 goto out;
 205         buf[len] = '\0';
 206
 207         /* The link should be "../..<origpath>/<sbuild_id>" */
 208         p = strrchr(buf, '/');  /* Cut off the "/<sbuild_id>" */
 209         if (p && (p > buf + offs)) {
 210                 *p = '\0';
 211                 if (buf[offs + 1] == '[')
 212                         offs++; /*
 213                                  * This is a DSO name, like [kernel.kallsyms].
 214                                  * Skip the first '/', since this is not the
 215                                  * cache of a regular file.
 216                                  */
 217                 ret = strdup(buf + offs);       /* Skip "../..[/]" */
 218         }
 219 out:
 220         free(linkname);
 221         return ret;
 222 }
 223
 224 /* Check if the given build_id cache is valid on current running system */
 225 static bool build_id_cache__valid_id(char *sbuild_id)
 226 {
 227         char real_sbuild_id[SBUILD_ID_SIZE] = "";
 228         char *pathname;
 229         int ret = 0;
 230         bool result = false;
 231
 232         pathname = build_id_cache__origname(sbuild_id);
 233         if (!pathname)
 234                 return false;
 235
 236         if (!strcmp(pathname, DSO__NAME_KALLSYMS))
 237                 ret = sysfs__sprintf_build_id("/", real_sbuild_id);
 238         else if (pathname[0] == '/')
 239                 ret = filename__sprintf_build_id(pathname, real_sbuild_id);
 240         else
 241                 ret = -EINVAL;  /* Should we support other special DSO cache? */
 242         if (ret >= 0)
 243                 result = (strcmp(sbuild_id, real_sbuild_id) == 0);
 244         free(pathname);
 245
 246         return result;
 247 }
 248
 249 static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso,
 250                                             bool is_debug)
 251 {
 252         return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : (is_debug ?
 253             "debug" : "elf"));
 254 }
 255
 256 char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
 257                              bool is_debug)
 258 {
 259         bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
 260         bool is_vdso = dso__is_vdso((struct dso *)dso);
 261         char sbuild_id[SBUILD_ID_SIZE];
 262         char *linkname;
 263         bool alloc = (bf == NULL);
 264         int ret;
 265
 266         if (!dso->has_build_id)
 267                 return NULL;
 268
 269         build_id__sprintf(dso->build_id, sizeof(dso->build_id), sbuild_id);
 270         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 271         if (!linkname)
 272                 return NULL;
 273
 274         /* Check if old style build_id cache */
 275         if (is_regular_file(linkname))
 276                 ret = asnprintf(&bf, size, "%s", linkname);
 277         else
 278                 ret = asnprintf(&bf, size, "%s/%s", linkname,
 279                          build_id_cache__basename(is_kallsyms, is_vdso,
 280                                                   is_debug));
 281         if (ret < 0 || (!alloc && size < (unsigned int)ret))
 282                 bf = NULL;
 283         free(linkname);
 284
 285         return bf;
 286 }
 287
 288 #define dsos__for_each_with_build_id(pos, head) \
 289         list_for_each_entry(pos, head, node)    \
 290                 if (!pos->has_build_id)         \
 291                         continue;               \
 292                 else
 293
 294 static int write_buildid(const char *name, size_t name_len, u8 *build_id,
 295                          pid_t pid, u16 misc, struct feat_fd *fd)
 296 {
 297         int err;
 298         struct build_id_event b;
 299         size_t len;
 300
 301         len = name_len + 1;
 302         len = PERF_ALIGN(len, NAME_ALIGN);
 303
 304         memset(&b, 0, sizeof(b));
 305         memcpy(&b.build_id, build_id, BUILD_ID_SIZE);
 306         b.pid = pid;
 307         b.header.misc = misc;
 308         b.header.size = sizeof(b) + len;
 309
 310         err = do_write(fd, &b, sizeof(b));
 311         if (err < 0)
 312                 return err;
 313
 314         return write_padded(fd, name, name_len + 1, len);
 315 }
 316
 317 static int machine__write_buildid_table(struct machine *machine,
 318                                         struct feat_fd *fd)
 319 {
 320         int err = 0;
 321         struct dso *pos;
 322         u16 kmisc = PERF_RECORD_MISC_KERNEL,
 323             umisc = PERF_RECORD_MISC_USER;
 324
 325         if (!machine__is_host(machine)) {
 326                 kmisc = PERF_RECORD_MISC_GUEST_KERNEL;
 327                 umisc = PERF_RECORD_MISC_GUEST_USER;
 328         }
 329
 330         dsos__for_each_with_build_id(pos, &machine->dsos.head) {
 331                 const char *name;
 332                 size_t name_len;
 333                 bool in_kernel = false;
 334
 335                 if (!pos->hit && !dso__is_vdso(pos))
 336                         continue;
 337
 338                 if (dso__is_vdso(pos)) {
 339                         name = pos->short_name;
 340                         name_len = pos->short_name_len;
 341                 } else if (dso__is_kcore(pos)) {
 342                         name = machine->mmap_name;
 343                         name_len = strlen(name);
 344                 } else {
 345                         name = pos->long_name;
 346                         name_len = pos->long_name_len;
 347                 }
 348
 349                 in_kernel = pos->kernel ||
 350                                 is_kernel_module(name,
 351                                         PERF_RECORD_MISC_CPUMODE_UNKNOWN);
 352                 err = write_buildid(name, name_len, pos->build_id, machine->pid,
 353                                     in_kernel ? kmisc : umisc, fd);
 354                 if (err)
 355                         break;
 356         }
 357
 358         return err;
 359 }
 360
 361 int perf_session__write_buildid_table(struct perf_session *session,
 362                                       struct feat_fd *fd)
 363 {
 364         struct rb_node *nd;
 365         int err = machine__write_buildid_table(&session->machines.host, fd);
 366
 367         if (err)
 368                 return err;
 369
 370         for (nd = rb_first_cached(&session->machines.guests); nd;
 371              nd = rb_next(nd)) {
 372                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 373                 err = machine__write_buildid_table(pos, fd);
 374                 if (err)
 375                         break;
 376         }
 377         return err;
 378 }
 379
 380 static int __dsos__hit_all(struct list_head *head)
 381 {
 382         struct dso *pos;
 383
 384         list_for_each_entry(pos, head, node)
 385                 pos->hit = true;
 386
 387         return 0;
 388 }
 389
 390 static int machine__hit_all_dsos(struct machine *machine)
 391 {
 392         return __dsos__hit_all(&machine->dsos.head);
 393 }
 394
 395 int dsos__hit_all(struct perf_session *session)
 396 {
 397         struct rb_node *nd;
 398         int err;
 399
 400         err = machine__hit_all_dsos(&session->machines.host);
 401         if (err)
 402                 return err;
 403
 404         for (nd = rb_first_cached(&session->machines.guests); nd;
 405              nd = rb_next(nd)) {
 406                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 407
 408                 err = machine__hit_all_dsos(pos);
 409                 if (err)
 410                         return err;
 411         }
 412
 413         return 0;
 414 }
 415
 416 void disable_buildid_cache(void)
 417 {
 418         no_buildid_cache = true;
 419 }
 420
 421 static bool lsdir_bid_head_filter(const char *name __maybe_unused,
 422                                   struct dirent *d)
 423 {
 424         return (strlen(d->d_name) == 2) &&
 425                 isxdigit(d->d_name[0]) && isxdigit(d->d_name[1]);
 426 }
 427
 428 static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
 429                                   struct dirent *d)
 430 {
 431         int i = 0;
 432         while (isxdigit(d->d_name[i]) && i < SBUILD_ID_SIZE - 3)
 433                 i++;
 434         return (i == SBUILD_ID_SIZE - 3) && (d->d_name[i] == '\0');
 435 }
 436
 437 struct strlist *build_id_cache__list_all(bool validonly)
 438 {
 439         struct strlist *toplist, *linklist = NULL, *bidlist;
 440         struct str_node *nd, *nd2;
 441         char *topdir, *linkdir = NULL;
 442         char sbuild_id[SBUILD_ID_SIZE];
 443
 444         /* for filename__ functions */
 445         if (validonly)
 446                 symbol__init(NULL);
 447
 448         /* Open the top-level directory */
 449         if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
 450                 return NULL;
 451
 452         bidlist = strlist__new(NULL, NULL);
 453         if (!bidlist)
 454                 goto out;
 455
 456         toplist = lsdir(topdir, lsdir_bid_head_filter);
 457         if (!toplist) {
 458                 pr_debug("Error in lsdir(%s): %d\n", topdir, errno);
 459                 /* If there is no buildid cache, return an empty list */
 460                 if (errno == ENOENT)
 461                         goto out;
 462                 goto err_out;
 463         }
 464
 465         strlist__for_each_entry(nd, toplist) {
 466                 if (asprintf(&linkdir, "%s/%s", topdir, nd->s) < 0)
 467                         goto err_out;
 468                 /* Open the lower-level directory */
 469                 linklist = lsdir(linkdir, lsdir_bid_tail_filter);
 470                 if (!linklist) {
 471                         pr_debug("Error in lsdir(%s): %d\n", linkdir, errno);
 472                         goto err_out;
 473                 }
 474                 strlist__for_each_entry(nd2, linklist) {
 475                         if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
 476                                      nd->s, nd2->s) != SBUILD_ID_SIZE - 1)
 477                                 goto err_out;
 478                         if (validonly && !build_id_cache__valid_id(sbuild_id))
 479                                 continue;
 480                         if (strlist__add(bidlist, sbuild_id) < 0)
 481                                 goto err_out;
 482                 }
 483                 strlist__delete(linklist);
 484                 zfree(&linkdir);
 485         }
 486
 487 out_free:
 488         strlist__delete(toplist);
 489 out:
 490         free(topdir);
 491
 492         return bidlist;
 493
 494 err_out:
 495         strlist__delete(linklist);
 496         zfree(&linkdir);
 497         strlist__delete(bidlist);
 498         bidlist = NULL;
 499         goto out_free;
 500 }
 501
 502 static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)
 503 {
 504         size_t i;
 505
 506         for (i = 0; i < len; i++) {
 507                 if (!isxdigit(maybe_sbuild_id[i]))
 508                         return false;
 509         }
 510         return true;
 511 }
 512
 513 /* Return the valid complete build-id */
 514 char *build_id_cache__complement(const char *incomplete_sbuild_id)
 515 {
 516         struct strlist *bidlist;
 517         struct str_node *nd, *cand = NULL;
 518         char *sbuild_id = NULL;
 519         size_t len = strlen(incomplete_sbuild_id);
 520
 521         if (len >= SBUILD_ID_SIZE ||
 522             !str_is_build_id(incomplete_sbuild_id, len))
 523                 return NULL;
 524
 525         bidlist = build_id_cache__list_all(true);
 526         if (!bidlist)
 527                 return NULL;
 528
 529         strlist__for_each_entry(nd, bidlist) {
 530                 if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)
 531                         continue;
 532                 if (cand) {     /* Error: There are more than 2 candidates. */
 533                         cand = NULL;
 534                         break;
 535                 }
 536                 cand = nd;
 537         }
 538         if (cand)
 539                 sbuild_id = strdup(cand->s);
 540         strlist__delete(bidlist);
 541
 542         return sbuild_id;
 543 }
 544
 545 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
 546                                struct nsinfo *nsi, bool is_kallsyms,
 547                                bool is_vdso)
 548 {
 549         char *realname = (char *)name, *filename;
 550         bool slash = is_kallsyms || is_vdso;
 551
 552         if (!slash) {
 553                 realname = nsinfo__realpath(name, nsi);
 554                 if (!realname)
 555                         return NULL;
 556         }
 557
 558         if (asprintf(&filename, "%s%s%s%s%s", buildid_dir, slash ? "/" : "",
 559                      is_vdso ? DSO__NAME_VDSO : realname,
 560                      sbuild_id ? "/" : "", sbuild_id ?: "") < 0)
 561                 filename = NULL;
 562
 563         if (!slash)
 564                 free(realname);
 565
 566         return filename;
 567 }
 568
 569 int build_id_cache__list_build_ids(const char *pathname, struct nsinfo *nsi,
 570                                    struct strlist **result)
 571 {
 572         char *dir_name;
 573         int ret = 0;
 574
 575         dir_name = build_id_cache__cachedir(NULL, pathname, nsi, false, false);
 576         if (!dir_name)
 577                 return -ENOMEM;
 578
 579         *result = lsdir(dir_name, lsdir_no_dot_filter);
 580         if (!*result)
 581                 ret = -errno;
 582         free(dir_name);
 583
 584         return ret;
 585 }
 586
 587 #if defined(HAVE_LIBELF_SUPPORT) && defined(HAVE_GELF_GETNOTE_SUPPORT)
 588 static int build_id_cache__add_sdt_cache(const char *sbuild_id,
 589                                           const char *realname,
 590                                           struct nsinfo *nsi)
 591 {
 592         struct probe_cache *cache;
 593         int ret;
 594         struct nscookie nsc;
 595
 596         cache = probe_cache__new(sbuild_id, nsi);
 597         if (!cache)
 598                 return -1;
 599
 600         nsinfo__mountns_enter(nsi, &nsc);
 601         ret = probe_cache__scan_sdt(cache, realname);
 602         nsinfo__mountns_exit(&nsc);
 603         if (ret >= 0) {
 604                 pr_debug4("Found %d SDTs in %s\n", ret, realname);
 605                 if (probe_cache__commit(cache) < 0)
 606                         ret = -1;
 607         }
 608         probe_cache__delete(cache);
 609         return ret;
 610 }
 611 #else
 612 #define build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) (0)
 613 #endif
 614
 615 static char *build_id_cache__find_debug(const char *sbuild_id,
 616                                         struct nsinfo *nsi)
 617 {
 618         char *realname = NULL;
 619         char *debugfile;
 620         struct nscookie nsc;
 621         size_t len = 0;
 622
 623         debugfile = calloc(1, PATH_MAX);
 624         if (!debugfile)
 625                 goto out;
 626
 627         len = __symbol__join_symfs(debugfile, PATH_MAX,
 628                                    "/usr/lib/debug/.build-id/");
 629         snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,
 630                  sbuild_id + 2);
 631
 632         nsinfo__mountns_enter(nsi, &nsc);
 633         realname = realpath(debugfile, NULL);
 634         if (realname && access(realname, R_OK))
 635                 zfree(&realname);
 636         nsinfo__mountns_exit(&nsc);
 637 out:
 638         free(debugfile);
 639         return realname;
 640 }
 641
 642 int build_id_cache__add_s(const char *sbuild_id, const char *name,
 643                           struct nsinfo *nsi, bool is_kallsyms, bool is_vdso)
 644 {
 645         const size_t size = PATH_MAX;
 646         char *realname = NULL, *filename = NULL, *dir_name = NULL,
 647              *linkname = zalloc(size), *tmp;
 648         char *debugfile = NULL;
 649         int err = -1;
 650
 651         if (!is_kallsyms) {
 652                 if (!is_vdso)
 653                         realname = nsinfo__realpath(name, nsi);
 654                 else
 655                         realname = realpath(name, NULL);
 656                 if (!realname)
 657                         goto out_free;
 658         }
 659
 660         dir_name = build_id_cache__cachedir(sbuild_id, name, nsi, is_kallsyms,
 661                                             is_vdso);
 662         if (!dir_name)
 663                 goto out_free;
 664
 665         /* Remove old style build-id cache */
 666         if (is_regular_file(dir_name))
 667                 if (unlink(dir_name))
 668                         goto out_free;
 669
 670         if (mkdir_p(dir_name, 0755))
 671                 goto out_free;
 672
 673         /* Save the allocated buildid dirname */
 674         if (asprintf(&filename, "%s/%s", dir_name,
 675                      build_id_cache__basename(is_kallsyms, is_vdso,
 676                      false)) < 0) {
 677                 filename = NULL;
 678                 goto out_free;
 679         }
 680
 681         if (access(filename, F_OK)) {
 682                 if (is_kallsyms) {
 683                         if (copyfile("/proc/kallsyms", filename))
 684                                 goto out_free;
 685                 } else if (nsi && nsi->need_setns) {
 686                         if (copyfile_ns(name, filename, nsi))
 687                                 goto out_free;
 688                 } else if (link(realname, filename) && errno != EEXIST &&
 689                                 copyfile(name, filename))
 690                         goto out_free;
 691         }
 692
 693         /* Some binaries are stripped, but have .debug files with their symbol
 694          * table.  Check to see if we can locate one of those, since the elf
 695          * file itself may not be very useful to users of our tools without a
 696          * symtab.
 697          */
 698         if (!is_kallsyms && !is_vdso &&
 699             strncmp(".ko", name + strlen(name) - 3, 3)) {
 700                 debugfile = build_id_cache__find_debug(sbuild_id, nsi);
 701                 if (debugfile) {
 702                         zfree(&filename);
 703                         if (asprintf(&filename, "%s/%s", dir_name,
 704                             build_id_cache__basename(false, false, true)) < 0) {
 705                                 filename = NULL;
 706                                 goto out_free;
 707                         }
 708                         if (access(filename, F_OK)) {
 709                                 if (nsi && nsi->need_setns) {
 710                                         if (copyfile_ns(debugfile, filename,
 711                                                         nsi))
 712                                                 goto out_free;
 713                                 } else if (link(debugfile, filename) &&
 714                                                 errno != EEXIST &&
 715                                                 copyfile(debugfile, filename))
 716                                         goto out_free;
 717                         }
 718                 }
 719         }
 720
 721         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 722                 goto out_free;
 723         tmp = strrchr(linkname, '/');
 724         *tmp = '\0';
 725
 726         if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
 727                 goto out_free;
 728
 729         *tmp = '/';
 730         tmp = dir_name + strlen(buildid_dir) - 5;
 731         memcpy(tmp, "../..", 5);
 732
 733         if (symlink(tmp, linkname) == 0)
 734                 err = 0;
 735
 736         /* Update SDT cache : error is just warned */
 737         if (realname &&
 738             build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) < 0)
 739                 pr_debug4("Failed to update/scan SDT cache for %s\n", realname);
 740
 741 out_free:
 742         if (!is_kallsyms)
 743                 free(realname);
 744         free(filename);
 745         free(debugfile);
 746         free(dir_name);
 747         free(linkname);
 748         return err;
 749 }
 750
 751 static int build_id_cache__add_b(const u8 *build_id, size_t build_id_size,
 752                                  const char *name, struct nsinfo *nsi,
 753                                  bool is_kallsyms, bool is_vdso)
 754 {
 755         char sbuild_id[SBUILD_ID_SIZE];
 756
 757         build_id__sprintf(build_id, build_id_size, sbuild_id);
 758
 759         return build_id_cache__add_s(sbuild_id, name, nsi, is_kallsyms,
 760                                      is_vdso);
 761 }
 762
 763 bool build_id_cache__cached(const char *sbuild_id)
 764 {
 765         bool ret = false;
 766         char *filename = build_id_cache__linkname(sbuild_id, NULL, 0);
 767
 768         if (filename && !access(filename, F_OK))
 769                 ret = true;
 770         free(filename);
 771
 772         return ret;
 773 }
 774
 775 int build_id_cache__remove_s(const char *sbuild_id)
 776 {
 777         const size_t size = PATH_MAX;
 778         char *filename = zalloc(size),
 779              *linkname = zalloc(size), *tmp;
 780         int err = -1;
 781
 782         if (filename == NULL || linkname == NULL)
 783                 goto out_free;
 784
 785         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 786                 goto out_free;
 787
 788         if (access(linkname, F_OK))
 789                 goto out_free;
 790
 791         if (readlink(linkname, filename, size - 1) < 0)
 792                 goto out_free;
 793
 794         if (unlink(linkname))
 795                 goto out_free;
 796
 797         /*
 798          * Since the link is relative, we must make it absolute:
 799          */
 800         tmp = strrchr(linkname, '/') + 1;
 801         snprintf(tmp, size - (tmp - linkname), "%s", filename);
 802
 803         if (rm_rf(linkname))
 804                 goto out_free;
 805
 806         err = 0;
 807 out_free:
 808         free(filename);
 809         free(linkname);
 810         return err;
 811 }
 812
 813 static int dso__cache_build_id(struct dso *dso, struct machine *machine)
 814 {
 815         bool is_kallsyms = dso__is_kallsyms(dso);
 816         bool is_vdso = dso__is_vdso(dso);
 817         const char *name = dso->long_name;
 818
 819         if (dso__is_kcore(dso)) {
 820                 is_kallsyms = true;
 821                 name = machine->mmap_name;
 822         }
 823         return build_id_cache__add_b(dso->build_id, sizeof(dso->build_id), name,
 824                                      dso->nsinfo, is_kallsyms, is_vdso);
 825 }
 826
 827 static int __dsos__cache_build_ids(struct list_head *head,
 828                                    struct machine *machine)
 829 {
 830         struct dso *pos;
 831         int err = 0;
 832
 833         dsos__for_each_with_build_id(pos, head)
 834                 if (dso__cache_build_id(pos, machine))
 835                         err = -1;
 836
 837         return err;
 838 }
 839
 840 static int machine__cache_build_ids(struct machine *machine)
 841 {
 842         return __dsos__cache_build_ids(&machine->dsos.head, machine);
 843 }
 844
 845 int perf_session__cache_build_ids(struct perf_session *session)
 846 {
 847         struct rb_node *nd;
 848         int ret;
 849
 850         if (no_buildid_cache)
 851                 return 0;
 852
 853         if (mkdir(buildid_dir, 0755) != 0 && errno != EEXIST)
 854                 return -1;
 855
 856         ret = machine__cache_build_ids(&session->machines.host);
 857
 858         for (nd = rb_first_cached(&session->machines.guests); nd;
 859              nd = rb_next(nd)) {
 860                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 861                 ret |= machine__cache_build_ids(pos);
 862         }
 863         return ret ? -1 : 0;
 864 }
 865
 866 static bool machine__read_build_ids(struct machine *machine, bool with_hits)
 867 {
 868         return __dsos__read_build_ids(&machine->dsos.head, with_hits);
 869 }
 870
 871 bool perf_session__read_build_ids(struct perf_session *session, bool with_hits)
 872 {
 873         struct rb_node *nd;
 874         bool ret = machine__read_build_ids(&session->machines.host, with_hits);
 875
 876         for (nd = rb_first_cached(&session->machines.guests); nd;
 877              nd = rb_next(nd)) {
 878                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 879                 ret |= machine__read_build_ids(pos, with_hits);
 880         }
 881
 882         return ret;
 883 }