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