tools/perf/util/build-id.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * build-id.c
   4  *
   5  * build-id support
   6  *
   7  * Copyright (C) 2009, 2010 Red Hat Inc.
   8  * Copyright (C) 2009, 2010 Arnaldo Carvalho de Melo <acme@redhat.com>
   9  */
  10 #include "util.h" // lsdir(), mkdir_p(), rm_rf()
  11 #include <dirent.h>
  12 #include <errno.h>
  13 #include <stdio.h>
  14 #include <sys/stat.h>
  15 #include <sys/types.h>
  16 #include "util/copyfile.h"
  17 #include "dso.h"
  18 #include "build-id.h"
  19 #include "event.h"
  20 #include "namespaces.h"
  21 #include "map.h"
  22 #include "symbol.h"
  23 #include "thread.h"
  24 #include <linux/kernel.h>
  25 #include "debug.h"
  26 #include "session.h"
  27 #include "tool.h"
  28 #include "header.h"
  29 #include "vdso.h"
  30 #include "path.h"
  31 #include "probe-file.h"
  32 #include "strlist.h"
  33
  34 #ifdef HAVE_DEBUGINFOD_SUPPORT
  35 #include <elfutils/debuginfod.h>
  36 #endif
  37
  38 #include <linux/ctype.h>
  39 #include <linux/zalloc.h>
  40 #include <linux/string.h>
  41 #include <asm/bug.h>
  42
  43 static bool no_buildid_cache;
  44
  45 int build_id__mark_dso_hit(struct perf_tool *tool __maybe_unused,
  46                            union perf_event *event,
  47                            struct perf_sample *sample,
  48                            struct evsel *evsel __maybe_unused,
  49                            struct machine *machine)
  50 {
  51         struct addr_location al;
  52         struct thread *thread = machine__findnew_thread(machine, sample->pid,
  53                                                         sample->tid);
  54
  55         if (thread == NULL) {
  56                 pr_err("problem processing %d event, skipping it.\n",
  57                         event->header.type);
  58                 return -1;
  59         }
  60
  61         if (thread__find_map(thread, sample->cpumode, sample->ip, &al))
  62                 al.map->dso->hit = 1;
  63
  64         thread__put(thread);
  65         return 0;
  66 }
  67
  68 static int perf_event__exit_del_thread(struct perf_tool *tool __maybe_unused,
  69                                        union perf_event *event,
  70                                        struct perf_sample *sample
  71                                        __maybe_unused,
  72                                        struct machine *machine)
  73 {
  74         struct thread *thread = machine__findnew_thread(machine,
  75                                                         event->fork.pid,
  76                                                         event->fork.tid);
  77
  78         dump_printf("(%d:%d):(%d:%d)\n", event->fork.pid, event->fork.tid,
  79                     event->fork.ppid, event->fork.ptid);
  80
  81         if (thread) {
  82                 machine__remove_thread(machine, thread);
  83                 thread__put(thread);
  84         }
  85
  86         return 0;
  87 }
  88
  89 struct perf_tool build_id__mark_dso_hit_ops = {
  90         .sample = build_id__mark_dso_hit,
  91         .mmap   = perf_event__process_mmap,
  92         .mmap2  = perf_event__process_mmap2,
  93         .fork   = perf_event__process_fork,
  94         .exit   = perf_event__exit_del_thread,
  95         .attr            = perf_event__process_attr,
  96         .build_id        = perf_event__process_build_id,
  97         .ordered_events  = true,
  98 };
  99
 100 int build_id__sprintf(const struct build_id *build_id, char *bf)
 101 {
 102         char *bid = bf;
 103         const u8 *raw = build_id->data;
 104         size_t i;
 105
 106         bf[0] = 0x0;
 107
 108         for (i = 0; i < build_id->size; ++i) {
 109                 sprintf(bid, "%02x", *raw);
 110                 ++raw;
 111                 bid += 2;
 112         }
 113
 114         return (bid - bf) + 1;
 115 }
 116
 117 int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id)
 118 {
 119         char notes[PATH_MAX];
 120         struct build_id bid;
 121         int ret;
 122
 123         if (!root_dir)
 124                 root_dir = "";
 125
 126         scnprintf(notes, sizeof(notes), "%s/sys/kernel/notes", root_dir);
 127
 128         ret = sysfs__read_build_id(notes, &bid);
 129         if (ret < 0)
 130                 return ret;
 131
 132         return build_id__sprintf(&bid, sbuild_id);
 133 }
 134
 135 int filename__sprintf_build_id(const char *pathname, char *sbuild_id)
 136 {
 137         struct build_id bid;
 138         int ret;
 139
 140         ret = filename__read_build_id(pathname, &bid);
 141         if (ret < 0)
 142                 return ret;
 143
 144         return build_id__sprintf(&bid, sbuild_id);
 145 }
 146
 147 /* asnprintf consolidates asprintf and snprintf */
 148 static int asnprintf(char **strp, size_t size, const char *fmt, ...)
 149 {
 150         va_list ap;
 151         int ret;
 152
 153         if (!strp)
 154                 return -EINVAL;
 155
 156         va_start(ap, fmt);
 157         if (*strp)
 158                 ret = vsnprintf(*strp, size, fmt, ap);
 159         else
 160                 ret = vasprintf(strp, fmt, ap);
 161         va_end(ap);
 162
 163         return ret;
 164 }
 165
 166 char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
 167                                     size_t size)
 168 {
 169         bool retry_old = true;
 170
 171         snprintf(bf, size, "%s/%s/%s/kallsyms",
 172                  buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
 173 retry:
 174         if (!access(bf, F_OK))
 175                 return bf;
 176         if (retry_old) {
 177                 /* Try old style kallsyms cache */
 178                 snprintf(bf, size, "%s/%s/%s",
 179                          buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
 180                 retry_old = false;
 181                 goto retry;
 182         }
 183
 184         return NULL;
 185 }
 186
 187 char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size)
 188 {
 189         char *tmp = bf;
 190         int ret = asnprintf(&bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
 191                             sbuild_id, sbuild_id + 2);
 192         if (ret < 0 || (tmp && size < (unsigned int)ret))
 193                 return NULL;
 194         return bf;
 195 }
 196
 197 /* The caller is responsible to free the returned buffer. */
 198 char *build_id_cache__origname(const char *sbuild_id)
 199 {
 200         char *linkname;
 201         char buf[PATH_MAX];
 202         char *ret = NULL, *p;
 203         size_t offs = 5;        /* == strlen("../..") */
 204         ssize_t len;
 205
 206         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 207         if (!linkname)
 208                 return NULL;
 209
 210         len = readlink(linkname, buf, sizeof(buf) - 1);
 211         if (len <= 0)
 212                 goto out;
 213         buf[len] = '\0';
 214
 215         /* The link should be "../..<origpath>/<sbuild_id>" */
 216         p = strrchr(buf, '/');  /* Cut off the "/<sbuild_id>" */
 217         if (p && (p > buf + offs)) {
 218                 *p = '\0';
 219                 if (buf[offs + 1] == '[')
 220                         offs++; /*
 221                                  * This is a DSO name, like [kernel.kallsyms].
 222                                  * Skip the first '/', since this is not the
 223                                  * cache of a regular file.
 224                                  */
 225                 ret = strdup(buf + offs);       /* Skip "../..[/]" */
 226         }
 227 out:
 228         free(linkname);
 229         return ret;
 230 }
 231
 232 /* Check if the given build_id cache is valid on current running system */
 233 static bool build_id_cache__valid_id(char *sbuild_id)
 234 {
 235         char real_sbuild_id[SBUILD_ID_SIZE] = "";
 236         char *pathname;
 237         int ret = 0;
 238         bool result = false;
 239
 240         pathname = build_id_cache__origname(sbuild_id);
 241         if (!pathname)
 242                 return false;
 243
 244         if (!strcmp(pathname, DSO__NAME_KALLSYMS))
 245                 ret = sysfs__sprintf_build_id("/", real_sbuild_id);
 246         else if (pathname[0] == '/')
 247                 ret = filename__sprintf_build_id(pathname, real_sbuild_id);
 248         else
 249                 ret = -EINVAL;  /* Should we support other special DSO cache? */
 250         if (ret >= 0)
 251                 result = (strcmp(sbuild_id, real_sbuild_id) == 0);
 252         free(pathname);
 253
 254         return result;
 255 }
 256
 257 static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso,
 258                                             bool is_debug)
 259 {
 260         return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : (is_debug ?
 261             "debug" : "elf"));
 262 }
 263
 264 char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
 265                              bool is_debug)
 266 {
 267         bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
 268         bool is_vdso = dso__is_vdso((struct dso *)dso);
 269         char sbuild_id[SBUILD_ID_SIZE];
 270         char *linkname;
 271         bool alloc = (bf == NULL);
 272         int ret;
 273
 274         if (!dso->has_build_id)
 275                 return NULL;
 276
 277         build_id__sprintf(&dso->bid, sbuild_id);
 278         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 279         if (!linkname)
 280                 return NULL;
 281
 282         /* Check if old style build_id cache */
 283         if (is_regular_file(linkname))
 284                 ret = asnprintf(&bf, size, "%s", linkname);
 285         else
 286                 ret = asnprintf(&bf, size, "%s/%s", linkname,
 287                          build_id_cache__basename(is_kallsyms, is_vdso,
 288                                                   is_debug));
 289         if (ret < 0 || (!alloc && size < (unsigned int)ret))
 290                 bf = NULL;
 291         free(linkname);
 292
 293         return bf;
 294 }
 295
 296 #define dsos__for_each_with_build_id(pos, head) \
 297         list_for_each_entry(pos, head, node)    \
 298                 if (!pos->has_build_id)         \
 299                         continue;               \
 300                 else
 301
 302 static int write_buildid(const char *name, size_t name_len, struct build_id *bid,
 303                          pid_t pid, u16 misc, struct feat_fd *fd)
 304 {
 305         int err;
 306         struct perf_record_header_build_id b;
 307         size_t len;
 308
 309         len = name_len + 1;
 310         len = PERF_ALIGN(len, NAME_ALIGN);
 311
 312         memset(&b, 0, sizeof(b));
 313         memcpy(&b.data, bid->data, bid->size);
 314         b.size = (u8) bid->size;
 315         misc |= PERF_RECORD_MISC_BUILD_ID_SIZE;
 316         b.pid = pid;
 317         b.header.misc = misc;
 318         b.header.size = sizeof(b) + len;
 319
 320         err = do_write(fd, &b, sizeof(b));
 321         if (err < 0)
 322                 return err;
 323
 324         return write_padded(fd, name, name_len + 1, len);
 325 }
 326
 327 static int machine__write_buildid_table(struct machine *machine,
 328                                         struct feat_fd *fd)
 329 {
 330         int err = 0;
 331         struct dso *pos;
 332         u16 kmisc = PERF_RECORD_MISC_KERNEL,
 333             umisc = PERF_RECORD_MISC_USER;
 334
 335         if (!machine__is_host(machine)) {
 336                 kmisc = PERF_RECORD_MISC_GUEST_KERNEL;
 337                 umisc = PERF_RECORD_MISC_GUEST_USER;
 338         }
 339
 340         dsos__for_each_with_build_id(pos, &machine->dsos.head) {
 341                 const char *name;
 342                 size_t name_len;
 343                 bool in_kernel = false;
 344
 345                 if (!pos->hit && !dso__is_vdso(pos))
 346                         continue;
 347
 348                 if (dso__is_vdso(pos)) {
 349                         name = pos->short_name;
 350                         name_len = pos->short_name_len;
 351                 } else if (dso__is_kcore(pos)) {
 352                         name = machine->mmap_name;
 353                         name_len = strlen(name);
 354                 } else {
 355                         name = pos->long_name;
 356                         name_len = pos->long_name_len;
 357                 }
 358
 359                 in_kernel = pos->kernel ||
 360                                 is_kernel_module(name,
 361                                         PERF_RECORD_MISC_CPUMODE_UNKNOWN);
 362                 err = write_buildid(name, name_len, &pos->bid, machine->pid,
 363                                     in_kernel ? kmisc : umisc, fd);
 364                 if (err)
 365                         break;
 366         }
 367
 368         return err;
 369 }
 370
 371 int perf_session__write_buildid_table(struct perf_session *session,
 372                                       struct feat_fd *fd)
 373 {
 374         struct rb_node *nd;
 375         int err = machine__write_buildid_table(&session->machines.host, fd);
 376
 377         if (err)
 378                 return err;
 379
 380         for (nd = rb_first_cached(&session->machines.guests); nd;
 381              nd = rb_next(nd)) {
 382                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 383                 err = machine__write_buildid_table(pos, fd);
 384                 if (err)
 385                         break;
 386         }
 387         return err;
 388 }
 389
 390 static int __dsos__hit_all(struct list_head *head)
 391 {
 392         struct dso *pos;
 393
 394         list_for_each_entry(pos, head, node)
 395                 pos->hit = true;
 396
 397         return 0;
 398 }
 399
 400 static int machine__hit_all_dsos(struct machine *machine)
 401 {
 402         return __dsos__hit_all(&machine->dsos.head);
 403 }
 404
 405 int dsos__hit_all(struct perf_session *session)
 406 {
 407         struct rb_node *nd;
 408         int err;
 409
 410         err = machine__hit_all_dsos(&session->machines.host);
 411         if (err)
 412                 return err;
 413
 414         for (nd = rb_first_cached(&session->machines.guests); nd;
 415              nd = rb_next(nd)) {
 416                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 417
 418                 err = machine__hit_all_dsos(pos);
 419                 if (err)
 420                         return err;
 421         }
 422
 423         return 0;
 424 }
 425
 426 void disable_buildid_cache(void)
 427 {
 428         no_buildid_cache = true;
 429 }
 430
 431 static bool lsdir_bid_head_filter(const char *name __maybe_unused,
 432                                   struct dirent *d)
 433 {
 434         return (strlen(d->d_name) == 2) &&
 435                 isxdigit(d->d_name[0]) && isxdigit(d->d_name[1]);
 436 }
 437
 438 static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
 439                                   struct dirent *d)
 440 {
 441         int i = 0;
 442         while (isxdigit(d->d_name[i]) && i < SBUILD_ID_SIZE - 3)
 443                 i++;
 444         return (i == SBUILD_ID_SIZE - 3) && (d->d_name[i] == '\0');
 445 }
 446
 447 struct strlist *build_id_cache__list_all(bool validonly)
 448 {
 449         struct strlist *toplist, *linklist = NULL, *bidlist;
 450         struct str_node *nd, *nd2;
 451         char *topdir, *linkdir = NULL;
 452         char sbuild_id[SBUILD_ID_SIZE];
 453
 454         /* for filename__ functions */
 455         if (validonly)
 456                 symbol__init(NULL);
 457
 458         /* Open the top-level directory */
 459         if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
 460                 return NULL;
 461
 462         bidlist = strlist__new(NULL, NULL);
 463         if (!bidlist)
 464                 goto out;
 465
 466         toplist = lsdir(topdir, lsdir_bid_head_filter);
 467         if (!toplist) {
 468                 pr_debug("Error in lsdir(%s): %d\n", topdir, errno);
 469                 /* If there is no buildid cache, return an empty list */
 470                 if (errno == ENOENT)
 471                         goto out;
 472                 goto err_out;
 473         }
 474
 475         strlist__for_each_entry(nd, toplist) {
 476                 if (asprintf(&linkdir, "%s/%s", topdir, nd->s) < 0)
 477                         goto err_out;
 478                 /* Open the lower-level directory */
 479                 linklist = lsdir(linkdir, lsdir_bid_tail_filter);
 480                 if (!linklist) {
 481                         pr_debug("Error in lsdir(%s): %d\n", linkdir, errno);
 482                         goto err_out;
 483                 }
 484                 strlist__for_each_entry(nd2, linklist) {
 485                         if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
 486                                      nd->s, nd2->s) != SBUILD_ID_SIZE - 1)
 487                                 goto err_out;
 488                         if (validonly && !build_id_cache__valid_id(sbuild_id))
 489                                 continue;
 490                         if (strlist__add(bidlist, sbuild_id) < 0)
 491                                 goto err_out;
 492                 }
 493                 strlist__delete(linklist);
 494                 zfree(&linkdir);
 495         }
 496
 497 out_free:
 498         strlist__delete(toplist);
 499 out:
 500         free(topdir);
 501
 502         return bidlist;
 503
 504 err_out:
 505         strlist__delete(linklist);
 506         zfree(&linkdir);
 507         strlist__delete(bidlist);
 508         bidlist = NULL;
 509         goto out_free;
 510 }
 511
 512 static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)
 513 {
 514         size_t i;
 515
 516         for (i = 0; i < len; i++) {
 517                 if (!isxdigit(maybe_sbuild_id[i]))
 518                         return false;
 519         }
 520         return true;
 521 }
 522
 523 /* Return the valid complete build-id */
 524 char *build_id_cache__complement(const char *incomplete_sbuild_id)
 525 {
 526         struct strlist *bidlist;
 527         struct str_node *nd, *cand = NULL;
 528         char *sbuild_id = NULL;
 529         size_t len = strlen(incomplete_sbuild_id);
 530
 531         if (len >= SBUILD_ID_SIZE ||
 532             !str_is_build_id(incomplete_sbuild_id, len))
 533                 return NULL;
 534
 535         bidlist = build_id_cache__list_all(true);
 536         if (!bidlist)
 537                 return NULL;
 538
 539         strlist__for_each_entry(nd, bidlist) {
 540                 if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)
 541                         continue;
 542                 if (cand) {     /* Error: There are more than 2 candidates. */
 543                         cand = NULL;
 544                         break;
 545                 }
 546                 cand = nd;
 547         }
 548         if (cand)
 549                 sbuild_id = strdup(cand->s);
 550         strlist__delete(bidlist);
 551
 552         return sbuild_id;
 553 }
 554
 555 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
 556                                struct nsinfo *nsi, bool is_kallsyms,
 557                                bool is_vdso)
 558 {
 559         char *realname = (char *)name, *filename;
 560         bool slash = is_kallsyms || is_vdso;
 561
 562         if (!slash) {
 563                 realname = nsinfo__realpath(name, nsi);
 564                 if (!realname)
 565                         return NULL;
 566         }
 567
 568         if (asprintf(&filename, "%s%s%s%s%s", buildid_dir, slash ? "/" : "",
 569                      is_vdso ? DSO__NAME_VDSO : realname,
 570                      sbuild_id ? "/" : "", sbuild_id ?: "") < 0)
 571                 filename = NULL;
 572
 573         if (!slash)
 574                 free(realname);
 575
 576         return filename;
 577 }
 578
 579 int build_id_cache__list_build_ids(const char *pathname, struct nsinfo *nsi,
 580                                    struct strlist **result)
 581 {
 582         char *dir_name;
 583         int ret = 0;
 584
 585         dir_name = build_id_cache__cachedir(NULL, pathname, nsi, false, false);
 586         if (!dir_name)
 587                 return -ENOMEM;
 588
 589         *result = lsdir(dir_name, lsdir_no_dot_filter);
 590         if (!*result)
 591                 ret = -errno;
 592         free(dir_name);
 593
 594         return ret;
 595 }
 596
 597 #if defined(HAVE_LIBELF_SUPPORT) && defined(HAVE_GELF_GETNOTE_SUPPORT)
 598 static int build_id_cache__add_sdt_cache(const char *sbuild_id,
 599                                           const char *realname,
 600                                           struct nsinfo *nsi)
 601 {
 602         struct probe_cache *cache;
 603         int ret;
 604         struct nscookie nsc;
 605
 606         cache = probe_cache__new(sbuild_id, nsi);
 607         if (!cache)
 608                 return -1;
 609
 610         nsinfo__mountns_enter(nsi, &nsc);
 611         ret = probe_cache__scan_sdt(cache, realname);
 612         nsinfo__mountns_exit(&nsc);
 613         if (ret >= 0) {
 614                 pr_debug4("Found %d SDTs in %s\n", ret, realname);
 615                 if (probe_cache__commit(cache) < 0)
 616                         ret = -1;
 617         }
 618         probe_cache__delete(cache);
 619         return ret;
 620 }
 621 #else
 622 #define build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) (0)
 623 #endif
 624
 625 static char *build_id_cache__find_debug(const char *sbuild_id,
 626                                         struct nsinfo *nsi)
 627 {
 628         char *realname = NULL;
 629         char *debugfile;
 630         struct nscookie nsc;
 631         size_t len = 0;
 632
 633         debugfile = calloc(1, PATH_MAX);
 634         if (!debugfile)
 635                 goto out;
 636
 637         len = __symbol__join_symfs(debugfile, PATH_MAX,
 638                                    "/usr/lib/debug/.build-id/");
 639         snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,
 640                  sbuild_id + 2);
 641
 642         nsinfo__mountns_enter(nsi, &nsc);
 643         realname = realpath(debugfile, NULL);
 644         if (realname && access(realname, R_OK))
 645                 zfree(&realname);
 646         nsinfo__mountns_exit(&nsc);
 647
 648 #ifdef HAVE_DEBUGINFOD_SUPPORT
 649         if (realname == NULL) {
 650                 debuginfod_client* c = debuginfod_begin();
 651                 if (c != NULL) {
 652                         int fd = debuginfod_find_debuginfo(c,
 653                                                            (const unsigned char*)sbuild_id, 0,
 654                                                            &realname);
 655                         if (fd >= 0)
 656                                 close(fd); /* retaining reference by realname */
 657                         debuginfod_end(c);
 658                 }
 659         }
 660 #endif
 661
 662 out:
 663         free(debugfile);
 664         return realname;
 665 }
 666
 667 int build_id_cache__add_s(const char *sbuild_id, const char *name,
 668                           struct nsinfo *nsi, bool is_kallsyms, bool is_vdso)
 669 {
 670         const size_t size = PATH_MAX;
 671         char *realname = NULL, *filename = NULL, *dir_name = NULL,
 672              *linkname = zalloc(size), *tmp;
 673         char *debugfile = NULL;
 674         int err = -1;
 675
 676         if (!is_kallsyms) {
 677                 if (!is_vdso)
 678                         realname = nsinfo__realpath(name, nsi);
 679                 else
 680                         realname = realpath(name, NULL);
 681                 if (!realname)
 682                         goto out_free;
 683         }
 684
 685         dir_name = build_id_cache__cachedir(sbuild_id, name, nsi, is_kallsyms,
 686                                             is_vdso);
 687         if (!dir_name)
 688                 goto out_free;
 689
 690         /* Remove old style build-id cache */
 691         if (is_regular_file(dir_name))
 692                 if (unlink(dir_name))
 693                         goto out_free;
 694
 695         if (mkdir_p(dir_name, 0755))
 696                 goto out_free;
 697
 698         /* Save the allocated buildid dirname */
 699         if (asprintf(&filename, "%s/%s", dir_name,
 700                      build_id_cache__basename(is_kallsyms, is_vdso,
 701                      false)) < 0) {
 702                 filename = NULL;
 703                 goto out_free;
 704         }
 705
 706         if (access(filename, F_OK)) {
 707                 if (is_kallsyms) {
 708                         if (copyfile("/proc/kallsyms", filename))
 709                                 goto out_free;
 710                 } else if (nsi && nsi->need_setns) {
 711                         if (copyfile_ns(name, filename, nsi))
 712                                 goto out_free;
 713                 } else if (link(realname, filename) && errno != EEXIST &&
 714                                 copyfile(name, filename))
 715                         goto out_free;
 716         }
 717
 718         /* Some binaries are stripped, but have .debug files with their symbol
 719          * table.  Check to see if we can locate one of those, since the elf
 720          * file itself may not be very useful to users of our tools without a
 721          * symtab.
 722          */
 723         if (!is_kallsyms && !is_vdso &&
 724             strncmp(".ko", name + strlen(name) - 3, 3)) {
 725                 debugfile = build_id_cache__find_debug(sbuild_id, nsi);
 726                 if (debugfile) {
 727                         zfree(&filename);
 728                         if (asprintf(&filename, "%s/%s", dir_name,
 729                             build_id_cache__basename(false, false, true)) < 0) {
 730                                 filename = NULL;
 731                                 goto out_free;
 732                         }
 733                         if (access(filename, F_OK)) {
 734                                 if (nsi && nsi->need_setns) {
 735                                         if (copyfile_ns(debugfile, filename,
 736                                                         nsi))
 737                                                 goto out_free;
 738                                 } else if (link(debugfile, filename) &&
 739                                                 errno != EEXIST &&
 740                                                 copyfile(debugfile, filename))
 741                                         goto out_free;
 742                         }
 743                 }
 744         }
 745
 746         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 747                 goto out_free;
 748         tmp = strrchr(linkname, '/');
 749         *tmp = '\0';
 750
 751         if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
 752                 goto out_free;
 753
 754         *tmp = '/';
 755         tmp = dir_name + strlen(buildid_dir) - 5;
 756         memcpy(tmp, "../..", 5);
 757
 758         if (symlink(tmp, linkname) == 0) {
 759                 err = 0;
 760         } else if (errno == EEXIST) {
 761                 char path[PATH_MAX];
 762                 ssize_t len;
 763
 764                 len = readlink(linkname, path, sizeof(path) - 1);
 765                 if (len <= 0) {
 766                         pr_err("Cant read link: %s\n", linkname);
 767                         goto out_free;
 768                 }
 769                 path[len] = '\0';
 770
 771                 if (strcmp(tmp, path)) {
 772                         pr_debug("build <%s> already linked to %s\n",
 773                                  sbuild_id, linkname);
 774                 }
 775                 err = 0;
 776         }
 777
 778         /* Update SDT cache : error is just warned */
 779         if (realname &&
 780             build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) < 0)
 781                 pr_debug4("Failed to update/scan SDT cache for %s\n", realname);
 782
 783 out_free:
 784         if (!is_kallsyms)
 785                 free(realname);
 786         free(filename);
 787         free(debugfile);
 788         free(dir_name);
 789         free(linkname);
 790         return err;
 791 }
 792
 793 static int build_id_cache__add_b(const struct build_id *bid,
 794                                  const char *name, struct nsinfo *nsi,
 795                                  bool is_kallsyms, bool is_vdso)
 796 {
 797         char sbuild_id[SBUILD_ID_SIZE];
 798
 799         build_id__sprintf(bid, sbuild_id);
 800
 801         return build_id_cache__add_s(sbuild_id, name, nsi, is_kallsyms,
 802                                      is_vdso);
 803 }
 804
 805 bool build_id_cache__cached(const char *sbuild_id)
 806 {
 807         bool ret = false;
 808         char *filename = build_id_cache__linkname(sbuild_id, NULL, 0);
 809
 810         if (filename && !access(filename, F_OK))
 811                 ret = true;
 812         free(filename);
 813
 814         return ret;
 815 }
 816
 817 int build_id_cache__remove_s(const char *sbuild_id)
 818 {
 819         const size_t size = PATH_MAX;
 820         char *filename = zalloc(size),
 821              *linkname = zalloc(size), *tmp;
 822         int err = -1;
 823
 824         if (filename == NULL || linkname == NULL)
 825                 goto out_free;
 826
 827         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 828                 goto out_free;
 829
 830         if (access(linkname, F_OK))
 831                 goto out_free;
 832
 833         if (readlink(linkname, filename, size - 1) < 0)
 834                 goto out_free;
 835
 836         if (unlink(linkname))
 837                 goto out_free;
 838
 839         /*
 840          * Since the link is relative, we must make it absolute:
 841          */
 842         tmp = strrchr(linkname, '/') + 1;
 843         snprintf(tmp, size - (tmp - linkname), "%s", filename);
 844
 845         if (rm_rf(linkname))
 846                 goto out_free;
 847
 848         err = 0;
 849 out_free:
 850         free(filename);
 851         free(linkname);
 852         return err;
 853 }
 854
 855 static int dso__cache_build_id(struct dso *dso, struct machine *machine)
 856 {
 857         bool is_kallsyms = dso__is_kallsyms(dso);
 858         bool is_vdso = dso__is_vdso(dso);
 859         const char *name = dso->long_name;
 860
 861         if (dso__is_kcore(dso)) {
 862                 is_kallsyms = true;
 863                 name = machine->mmap_name;
 864         }
 865         return build_id_cache__add_b(&dso->bid, name, dso->nsinfo,
 866                                      is_kallsyms, is_vdso);
 867 }
 868
 869 static int __dsos__cache_build_ids(struct list_head *head,
 870                                    struct machine *machine)
 871 {
 872         struct dso *pos;
 873         int err = 0;
 874
 875         dsos__for_each_with_build_id(pos, head)
 876                 if (dso__cache_build_id(pos, machine))
 877                         err = -1;
 878
 879         return err;
 880 }
 881
 882 static int machine__cache_build_ids(struct machine *machine)
 883 {
 884         return __dsos__cache_build_ids(&machine->dsos.head, machine);
 885 }
 886
 887 int perf_session__cache_build_ids(struct perf_session *session)
 888 {
 889         struct rb_node *nd;
 890         int ret;
 891
 892         if (no_buildid_cache)
 893                 return 0;
 894
 895         if (mkdir(buildid_dir, 0755) != 0 && errno != EEXIST)
 896                 return -1;
 897
 898         ret = machine__cache_build_ids(&session->machines.host);
 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__cache_build_ids(pos);
 904         }
 905         return ret ? -1 : 0;
 906 }
 907
 908 static bool machine__read_build_ids(struct machine *machine, bool with_hits)
 909 {
 910         return __dsos__read_build_ids(&machine->dsos.head, with_hits);
 911 }
 912
 913 bool perf_session__read_build_ids(struct perf_session *session, bool with_hits)
 914 {
 915         struct rb_node *nd;
 916         bool ret = machine__read_build_ids(&session->machines.host, with_hits);
 917
 918         for (nd = rb_first_cached(&session->machines.guests); nd;
 919              nd = rb_next(nd)) {
 920                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 921                 ret |= machine__read_build_ids(pos, with_hits);
 922         }
 923
 924         return ret;
 925 }
 926
 927 void build_id__init(struct build_id *bid, const u8 *data, size_t size)
 928 {
 929         WARN_ON(size > BUILD_ID_SIZE);
 930         memcpy(bid->data, data, size);
 931         bid->size = size;
 932 }
 933
 934 bool build_id__is_defined(const struct build_id *bid)
 935 {
 936         return bid && bid->size ? !!memchr_inv(bid->data, 0, bid->size) : false;
 937 }