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 <[email protected]>
   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(const 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         addr_location__init(&al);
  62         if (thread__find_map(thread, sample->cpumode, sample->ip, &al))
  63                 dso__set_hit(map__dso(al.map));
  64
  65         addr_location__exit(&al);
  66         thread__put(thread);
  67         return 0;
  68 }
  69
  70 int build_id__sprintf(const struct build_id *build_id, char *bf)
  71 {
  72         char *bid = bf;
  73         const u8 *raw = build_id->data;
  74         size_t i;
  75
  76         bf[0] = 0x0;
  77
  78         for (i = 0; i < build_id->size; ++i) {
  79                 sprintf(bid, "%02x", *raw);
  80                 ++raw;
  81                 bid += 2;
  82         }
  83
  84         return (bid - bf) + 1;
  85 }
  86
  87 int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id)
  88 {
  89         char notes[PATH_MAX];
  90         struct build_id bid;
  91         int ret;
  92
  93         if (!root_dir)
  94                 root_dir = "";
  95
  96         scnprintf(notes, sizeof(notes), "%s/sys/kernel/notes", root_dir);
  97
  98         ret = sysfs__read_build_id(notes, &bid);
  99         if (ret < 0)
 100                 return ret;
 101
 102         return build_id__sprintf(&bid, sbuild_id);
 103 }
 104
 105 int filename__sprintf_build_id(const char *pathname, char *sbuild_id)
 106 {
 107         struct build_id bid;
 108         int ret;
 109
 110         ret = filename__read_build_id(pathname, &bid);
 111         if (ret < 0)
 112                 return ret;
 113
 114         return build_id__sprintf(&bid, sbuild_id);
 115 }
 116
 117 /* asnprintf consolidates asprintf and snprintf */
 118 static int asnprintf(char **strp, size_t size, const char *fmt, ...)
 119 {
 120         va_list ap;
 121         int ret;
 122
 123         if (!strp)
 124                 return -EINVAL;
 125
 126         va_start(ap, fmt);
 127         if (*strp)
 128                 ret = vsnprintf(*strp, size, fmt, ap);
 129         else
 130                 ret = vasprintf(strp, fmt, ap);
 131         va_end(ap);
 132
 133         return ret;
 134 }
 135
 136 char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
 137                                     size_t size)
 138 {
 139         bool retry_old = true;
 140
 141         snprintf(bf, size, "%s/%s/%s/kallsyms",
 142                  buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
 143 retry:
 144         if (!access(bf, F_OK))
 145                 return bf;
 146         if (retry_old) {
 147                 /* Try old style kallsyms cache */
 148                 snprintf(bf, size, "%s/%s/%s",
 149                          buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
 150                 retry_old = false;
 151                 goto retry;
 152         }
 153
 154         return NULL;
 155 }
 156
 157 char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size)
 158 {
 159         char *tmp = bf;
 160         int ret = asnprintf(&bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
 161                             sbuild_id, sbuild_id + 2);
 162         if (ret < 0 || (tmp && size < (unsigned int)ret))
 163                 return NULL;
 164         return bf;
 165 }
 166
 167 /* The caller is responsible to free the returned buffer. */
 168 char *build_id_cache__origname(const char *sbuild_id)
 169 {
 170         char *linkname;
 171         char buf[PATH_MAX];
 172         char *ret = NULL, *p;
 173         size_t offs = 5;        /* == strlen("../..") */
 174         ssize_t len;
 175
 176         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 177         if (!linkname)
 178                 return NULL;
 179
 180         len = readlink(linkname, buf, sizeof(buf) - 1);
 181         if (len <= 0)
 182                 goto out;
 183         buf[len] = '\0';
 184
 185         /* The link should be "../..<origpath>/<sbuild_id>" */
 186         p = strrchr(buf, '/');  /* Cut off the "/<sbuild_id>" */
 187         if (p && (p > buf + offs)) {
 188                 *p = '\0';
 189                 if (buf[offs + 1] == '[')
 190                         offs++; /*
 191                                  * This is a DSO name, like [kernel.kallsyms].
 192                                  * Skip the first '/', since this is not the
 193                                  * cache of a regular file.
 194                                  */
 195                 ret = strdup(buf + offs);       /* Skip "../..[/]" */
 196         }
 197 out:
 198         free(linkname);
 199         return ret;
 200 }
 201
 202 /* Check if the given build_id cache is valid on current running system */
 203 static bool build_id_cache__valid_id(char *sbuild_id)
 204 {
 205         char real_sbuild_id[SBUILD_ID_SIZE] = "";
 206         char *pathname;
 207         int ret = 0;
 208         bool result = false;
 209
 210         pathname = build_id_cache__origname(sbuild_id);
 211         if (!pathname)
 212                 return false;
 213
 214         if (!strcmp(pathname, DSO__NAME_KALLSYMS))
 215                 ret = sysfs__sprintf_build_id("/", real_sbuild_id);
 216         else if (pathname[0] == '/')
 217                 ret = filename__sprintf_build_id(pathname, real_sbuild_id);
 218         else
 219                 ret = -EINVAL;  /* Should we support other special DSO cache? */
 220         if (ret >= 0)
 221                 result = (strcmp(sbuild_id, real_sbuild_id) == 0);
 222         free(pathname);
 223
 224         return result;
 225 }
 226
 227 static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso,
 228                                             bool is_debug)
 229 {
 230         return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : (is_debug ?
 231             "debug" : "elf"));
 232 }
 233
 234 char *__dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
 235                                bool is_debug, bool is_kallsyms)
 236 {
 237         bool is_vdso = dso__is_vdso((struct dso *)dso);
 238         char sbuild_id[SBUILD_ID_SIZE];
 239         char *linkname;
 240         bool alloc = (bf == NULL);
 241         int ret;
 242
 243         if (!dso__has_build_id(dso))
 244                 return NULL;
 245
 246         build_id__sprintf(dso__bid_const(dso), sbuild_id);
 247         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 248         if (!linkname)
 249                 return NULL;
 250
 251         /* Check if old style build_id cache */
 252         if (is_regular_file(linkname))
 253                 ret = asnprintf(&bf, size, "%s", linkname);
 254         else
 255                 ret = asnprintf(&bf, size, "%s/%s", linkname,
 256                          build_id_cache__basename(is_kallsyms, is_vdso,
 257                                                   is_debug));
 258         if (ret < 0 || (!alloc && size < (unsigned int)ret))
 259                 bf = NULL;
 260         free(linkname);
 261
 262         return bf;
 263 }
 264
 265 char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
 266                              bool is_debug)
 267 {
 268         bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
 269
 270         return __dso__build_id_filename(dso, bf, size, is_debug, is_kallsyms);
 271 }
 272
 273 static int write_buildid(const char *name, size_t name_len, struct build_id *bid,
 274                          pid_t pid, u16 misc, struct feat_fd *fd)
 275 {
 276         int err;
 277         struct perf_record_header_build_id b;
 278         size_t len;
 279
 280         len = name_len + 1;
 281         len = PERF_ALIGN(len, sizeof(u64));
 282
 283         memset(&b, 0, sizeof(b));
 284         memcpy(&b.data, bid->data, bid->size);
 285         b.size = (u8) bid->size;
 286         misc |= PERF_RECORD_MISC_BUILD_ID_SIZE;
 287         b.pid = pid;
 288         b.header.misc = misc;
 289         b.header.size = sizeof(b) + len;
 290
 291         err = do_write(fd, &b, sizeof(b));
 292         if (err < 0)
 293                 return err;
 294
 295         return write_padded(fd, name, name_len + 1, len);
 296 }
 297
 298 struct machine__write_buildid_table_cb_args {
 299         struct machine *machine;
 300         struct feat_fd *fd;
 301         u16 kmisc, umisc;
 302 };
 303
 304 static int machine__write_buildid_table_cb(struct dso *dso, void *data)
 305 {
 306         struct machine__write_buildid_table_cb_args *args = data;
 307         const char *name;
 308         size_t name_len;
 309         bool in_kernel = false;
 310
 311         if (!dso__has_build_id(dso))
 312                 return 0;
 313
 314         if (!dso__hit(dso) && !dso__is_vdso(dso))
 315                 return 0;
 316
 317         if (dso__is_vdso(dso)) {
 318                 name = dso__short_name(dso);
 319                 name_len = dso__short_name_len(dso);
 320         } else if (dso__is_kcore(dso)) {
 321                 name = args->machine->mmap_name;
 322                 name_len = strlen(name);
 323         } else {
 324                 name = dso__long_name(dso);
 325                 name_len = dso__long_name_len(dso);
 326         }
 327
 328         in_kernel = dso__kernel(dso) || is_kernel_module(name, PERF_RECORD_MISC_CPUMODE_UNKNOWN);
 329         return write_buildid(name, name_len, dso__bid(dso), args->machine->pid,
 330                              in_kernel ? args->kmisc : args->umisc, args->fd);
 331 }
 332
 333 static int machine__write_buildid_table(struct machine *machine, struct feat_fd *fd)
 334 {
 335         struct machine__write_buildid_table_cb_args args = {
 336                 .machine = machine,
 337                 .fd = fd,
 338                 .kmisc = PERF_RECORD_MISC_KERNEL,
 339                 .umisc = PERF_RECORD_MISC_USER,
 340         };
 341
 342         if (!machine__is_host(machine)) {
 343                 args.kmisc = PERF_RECORD_MISC_GUEST_KERNEL;
 344                 args.umisc = PERF_RECORD_MISC_GUEST_USER;
 345         }
 346
 347         return dsos__for_each_dso(&machine->dsos, machine__write_buildid_table_cb, &args);
 348 }
 349
 350 int perf_session__write_buildid_table(struct perf_session *session,
 351                                       struct feat_fd *fd)
 352 {
 353         struct rb_node *nd;
 354         int err = machine__write_buildid_table(&session->machines.host, fd);
 355
 356         if (err)
 357                 return err;
 358
 359         for (nd = rb_first_cached(&session->machines.guests); nd;
 360              nd = rb_next(nd)) {
 361                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 362                 err = machine__write_buildid_table(pos, fd);
 363                 if (err)
 364                         break;
 365         }
 366         return err;
 367 }
 368
 369 void disable_buildid_cache(void)
 370 {
 371         no_buildid_cache = true;
 372 }
 373
 374 static bool lsdir_bid_head_filter(const char *name __maybe_unused,
 375                                   struct dirent *d)
 376 {
 377         return (strlen(d->d_name) == 2) &&
 378                 isxdigit(d->d_name[0]) && isxdigit(d->d_name[1]);
 379 }
 380
 381 static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
 382                                   struct dirent *d)
 383 {
 384         int i = 0;
 385         while (isxdigit(d->d_name[i]) && i < SBUILD_ID_SIZE - 3)
 386                 i++;
 387         return (i >= SBUILD_ID_MIN_SIZE - 3) && (i <= SBUILD_ID_SIZE - 3) &&
 388                 (d->d_name[i] == '\0');
 389 }
 390
 391 struct strlist *build_id_cache__list_all(bool validonly)
 392 {
 393         struct strlist *toplist, *linklist = NULL, *bidlist;
 394         struct str_node *nd, *nd2;
 395         char *topdir, *linkdir = NULL;
 396         char sbuild_id[SBUILD_ID_SIZE];
 397
 398         /* for filename__ functions */
 399         if (validonly)
 400                 symbol__init(NULL);
 401
 402         /* Open the top-level directory */
 403         if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
 404                 return NULL;
 405
 406         bidlist = strlist__new(NULL, NULL);
 407         if (!bidlist)
 408                 goto out;
 409
 410         toplist = lsdir(topdir, lsdir_bid_head_filter);
 411         if (!toplist) {
 412                 pr_debug("Error in lsdir(%s): %d\n", topdir, errno);
 413                 /* If there is no buildid cache, return an empty list */
 414                 if (errno == ENOENT)
 415                         goto out;
 416                 goto err_out;
 417         }
 418
 419         strlist__for_each_entry(nd, toplist) {
 420                 if (asprintf(&linkdir, "%s/%s", topdir, nd->s) < 0)
 421                         goto err_out;
 422                 /* Open the lower-level directory */
 423                 linklist = lsdir(linkdir, lsdir_bid_tail_filter);
 424                 if (!linklist) {
 425                         pr_debug("Error in lsdir(%s): %d\n", linkdir, errno);
 426                         goto err_out;
 427                 }
 428                 strlist__for_each_entry(nd2, linklist) {
 429                         if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
 430                                      nd->s, nd2->s) > SBUILD_ID_SIZE - 1)
 431                                 goto err_out;
 432                         if (validonly && !build_id_cache__valid_id(sbuild_id))
 433                                 continue;
 434                         if (strlist__add(bidlist, sbuild_id) < 0)
 435                                 goto err_out;
 436                 }
 437                 strlist__delete(linklist);
 438                 zfree(&linkdir);
 439         }
 440
 441 out_free:
 442         strlist__delete(toplist);
 443 out:
 444         free(topdir);
 445
 446         return bidlist;
 447
 448 err_out:
 449         strlist__delete(linklist);
 450         zfree(&linkdir);
 451         strlist__delete(bidlist);
 452         bidlist = NULL;
 453         goto out_free;
 454 }
 455
 456 static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)
 457 {
 458         size_t i;
 459
 460         for (i = 0; i < len; i++) {
 461                 if (!isxdigit(maybe_sbuild_id[i]))
 462                         return false;
 463         }
 464         return true;
 465 }
 466
 467 /* Return the valid complete build-id */
 468 char *build_id_cache__complement(const char *incomplete_sbuild_id)
 469 {
 470         struct strlist *bidlist;
 471         struct str_node *nd, *cand = NULL;
 472         char *sbuild_id = NULL;
 473         size_t len = strlen(incomplete_sbuild_id);
 474
 475         if (len >= SBUILD_ID_SIZE ||
 476             !str_is_build_id(incomplete_sbuild_id, len))
 477                 return NULL;
 478
 479         bidlist = build_id_cache__list_all(true);
 480         if (!bidlist)
 481                 return NULL;
 482
 483         strlist__for_each_entry(nd, bidlist) {
 484                 if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)
 485                         continue;
 486                 if (cand) {     /* Error: There are more than 2 candidates. */
 487                         cand = NULL;
 488                         break;
 489                 }
 490                 cand = nd;
 491         }
 492         if (cand)
 493                 sbuild_id = strdup(cand->s);
 494         strlist__delete(bidlist);
 495
 496         return sbuild_id;
 497 }
 498
 499 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
 500                                struct nsinfo *nsi, bool is_kallsyms,
 501                                bool is_vdso)
 502 {
 503         char *realname = NULL, *filename;
 504         bool slash = is_kallsyms || is_vdso;
 505
 506         if (!slash)
 507                 realname = nsinfo__realpath(name, nsi);
 508
 509         if (asprintf(&filename, "%s%s%s%s%s", buildid_dir, slash ? "/" : "",
 510                      is_vdso ? DSO__NAME_VDSO : (realname ? realname : name),
 511                      sbuild_id ? "/" : "", sbuild_id ?: "") < 0)
 512                 filename = NULL;
 513
 514         free(realname);
 515         return filename;
 516 }
 517
 518 int build_id_cache__list_build_ids(const char *pathname, struct nsinfo *nsi,
 519                                    struct strlist **result)
 520 {
 521         char *dir_name;
 522         int ret = 0;
 523
 524         dir_name = build_id_cache__cachedir(NULL, pathname, nsi, false, false);
 525         if (!dir_name)
 526                 return -ENOMEM;
 527
 528         *result = lsdir(dir_name, lsdir_no_dot_filter);
 529         if (!*result)
 530                 ret = -errno;
 531         free(dir_name);
 532
 533         return ret;
 534 }
 535
 536 #if defined(HAVE_LIBELF_SUPPORT) && defined(HAVE_GELF_GETNOTE_SUPPORT)
 537 static int build_id_cache__add_sdt_cache(const char *sbuild_id,
 538                                           const char *realname,
 539                                           struct nsinfo *nsi)
 540 {
 541         struct probe_cache *cache;
 542         int ret;
 543         struct nscookie nsc;
 544
 545         cache = probe_cache__new(sbuild_id, nsi);
 546         if (!cache)
 547                 return -1;
 548
 549         nsinfo__mountns_enter(nsi, &nsc);
 550         ret = probe_cache__scan_sdt(cache, realname);
 551         nsinfo__mountns_exit(&nsc);
 552         if (ret >= 0) {
 553                 pr_debug4("Found %d SDTs in %s\n", ret, realname);
 554                 if (probe_cache__commit(cache) < 0)
 555                         ret = -1;
 556         }
 557         probe_cache__delete(cache);
 558         return ret;
 559 }
 560 #else
 561 #define build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) (0)
 562 #endif
 563
 564 static char *build_id_cache__find_debug(const char *sbuild_id,
 565                                         struct nsinfo *nsi,
 566                                         const char *root_dir)
 567 {
 568         const char *dirname = "/usr/lib/debug/.build-id/";
 569         char *realname = NULL;
 570         char dirbuf[PATH_MAX];
 571         char *debugfile;
 572         struct nscookie nsc;
 573         size_t len = 0;
 574
 575         debugfile = calloc(1, PATH_MAX);
 576         if (!debugfile)
 577                 goto out;
 578
 579         if (root_dir) {
 580                 path__join(dirbuf, PATH_MAX, root_dir, dirname);
 581                 dirname = dirbuf;
 582         }
 583
 584         len = __symbol__join_symfs(debugfile, PATH_MAX, dirname);
 585         snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,
 586                  sbuild_id + 2);
 587
 588         nsinfo__mountns_enter(nsi, &nsc);
 589         realname = realpath(debugfile, NULL);
 590         if (realname && access(realname, R_OK))
 591                 zfree(&realname);
 592         nsinfo__mountns_exit(&nsc);
 593
 594 #ifdef HAVE_DEBUGINFOD_SUPPORT
 595         if (realname == NULL) {
 596                 debuginfod_client* c;
 597
 598                 pr_debug("Downloading debug info with build id %s\n", sbuild_id);
 599
 600                 c = debuginfod_begin();
 601                 if (c != NULL) {
 602                         int fd = debuginfod_find_debuginfo(c,
 603                                         (const unsigned char*)sbuild_id, 0,
 604                                         &realname);
 605                         if (fd >= 0)
 606                                 close(fd); /* retaining reference by realname */
 607                         debuginfod_end(c);
 608                 }
 609         }
 610 #endif
 611
 612 out:
 613         free(debugfile);
 614         return realname;
 615 }
 616
 617 int
 618 build_id_cache__add(const char *sbuild_id, const char *name, const char *realname,
 619                     struct nsinfo *nsi, bool is_kallsyms, bool is_vdso,
 620                     const char *proper_name, const char *root_dir)
 621 {
 622         const size_t size = PATH_MAX;
 623         char *filename = NULL, *dir_name = NULL, *linkname = zalloc(size), *tmp;
 624         char *debugfile = NULL;
 625         int err = -1;
 626
 627         if (!proper_name)
 628                 proper_name = name;
 629
 630         dir_name = build_id_cache__cachedir(sbuild_id, proper_name, nsi, is_kallsyms,
 631                                             is_vdso);
 632         if (!dir_name)
 633                 goto out_free;
 634
 635         /* Remove old style build-id cache */
 636         if (is_regular_file(dir_name))
 637                 if (unlink(dir_name))
 638                         goto out_free;
 639
 640         if (mkdir_p(dir_name, 0755))
 641                 goto out_free;
 642
 643         /* Save the allocated buildid dirname */
 644         if (asprintf(&filename, "%s/%s", dir_name,
 645                      build_id_cache__basename(is_kallsyms, is_vdso,
 646                      false)) < 0) {
 647                 filename = NULL;
 648                 goto out_free;
 649         }
 650
 651         if (access(filename, F_OK)) {
 652                 if (is_kallsyms) {
 653                         if (copyfile("/proc/kallsyms", filename))
 654                                 goto out_free;
 655                 } else if (nsi && nsinfo__need_setns(nsi)) {
 656                         if (copyfile_ns(name, filename, nsi))
 657                                 goto out_free;
 658                 } else if (link(realname, filename) && errno != EEXIST) {
 659                         struct stat f_stat;
 660
 661                         if (!(stat(name, &f_stat) < 0) &&
 662                                         copyfile_mode(name, filename, f_stat.st_mode))
 663                                 goto out_free;
 664                 }
 665         }
 666
 667         /* Some binaries are stripped, but have .debug files with their symbol
 668          * table.  Check to see if we can locate one of those, since the elf
 669          * file itself may not be very useful to users of our tools without a
 670          * symtab.
 671          */
 672         if (!is_kallsyms && !is_vdso &&
 673             strncmp(".ko", name + strlen(name) - 3, 3)) {
 674                 debugfile = build_id_cache__find_debug(sbuild_id, nsi, root_dir);
 675                 if (debugfile) {
 676                         zfree(&filename);
 677                         if (asprintf(&filename, "%s/%s", dir_name,
 678                             build_id_cache__basename(false, false, true)) < 0) {
 679                                 filename = NULL;
 680                                 goto out_free;
 681                         }
 682                         if (access(filename, F_OK)) {
 683                                 if (nsi && nsinfo__need_setns(nsi)) {
 684                                         if (copyfile_ns(debugfile, filename,
 685                                                         nsi))
 686                                                 goto out_free;
 687                                 } else if (link(debugfile, filename) &&
 688                                                 errno != EEXIST &&
 689                                                 copyfile(debugfile, filename))
 690                                         goto out_free;
 691                         }
 692                 }
 693         }
 694
 695         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 696                 goto out_free;
 697         tmp = strrchr(linkname, '/');
 698         *tmp = '\0';
 699
 700         if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
 701                 goto out_free;
 702
 703         *tmp = '/';
 704         tmp = dir_name + strlen(buildid_dir) - 5;
 705         memcpy(tmp, "../..", 5);
 706
 707         if (symlink(tmp, linkname) == 0) {
 708                 err = 0;
 709         } else if (errno == EEXIST) {
 710                 char path[PATH_MAX];
 711                 ssize_t len;
 712
 713                 len = readlink(linkname, path, sizeof(path) - 1);
 714                 if (len <= 0) {
 715                         pr_err("Can't read link: %s\n", linkname);
 716                         goto out_free;
 717                 }
 718                 path[len] = '\0';
 719
 720                 if (strcmp(tmp, path)) {
 721                         pr_debug("build <%s> already linked to %s\n",
 722                                  sbuild_id, linkname);
 723                 }
 724                 err = 0;
 725         }
 726
 727         /* Update SDT cache : error is just warned */
 728         if (realname &&
 729             build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) < 0)
 730                 pr_debug4("Failed to update/scan SDT cache for %s\n", realname);
 731
 732 out_free:
 733         free(filename);
 734         free(debugfile);
 735         free(dir_name);
 736         free(linkname);
 737         return err;
 738 }
 739
 740 int __build_id_cache__add_s(const char *sbuild_id, const char *name,
 741                             struct nsinfo *nsi, bool is_kallsyms, bool is_vdso,
 742                             const char *proper_name, const char *root_dir)
 743 {
 744         char *realname = NULL;
 745         int err = -1;
 746
 747         if (!is_kallsyms) {
 748                 if (!is_vdso)
 749                         realname = nsinfo__realpath(name, nsi);
 750                 else
 751                         realname = realpath(name, NULL);
 752                 if (!realname)
 753                         goto out_free;
 754         }
 755
 756         err = build_id_cache__add(sbuild_id, name, realname, nsi,
 757                                   is_kallsyms, is_vdso, proper_name, root_dir);
 758 out_free:
 759         if (!is_kallsyms)
 760                 free(realname);
 761         return err;
 762 }
 763
 764 static int build_id_cache__add_b(const struct build_id *bid,
 765                                  const char *name, struct nsinfo *nsi,
 766                                  bool is_kallsyms, bool is_vdso,
 767                                  const char *proper_name,
 768                                  const char *root_dir)
 769 {
 770         char sbuild_id[SBUILD_ID_SIZE];
 771
 772         build_id__sprintf(bid, sbuild_id);
 773
 774         return __build_id_cache__add_s(sbuild_id, name, nsi, is_kallsyms,
 775                                        is_vdso, proper_name, root_dir);
 776 }
 777
 778 bool build_id_cache__cached(const char *sbuild_id)
 779 {
 780         bool ret = false;
 781         char *filename = build_id_cache__linkname(sbuild_id, NULL, 0);
 782
 783         if (filename && !access(filename, F_OK))
 784                 ret = true;
 785         free(filename);
 786
 787         return ret;
 788 }
 789
 790 int build_id_cache__remove_s(const char *sbuild_id)
 791 {
 792         const size_t size = PATH_MAX;
 793         char *filename = zalloc(size),
 794              *linkname = zalloc(size), *tmp;
 795         int err = -1;
 796
 797         if (filename == NULL || linkname == NULL)
 798                 goto out_free;
 799
 800         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 801                 goto out_free;
 802
 803         if (access(linkname, F_OK))
 804                 goto out_free;
 805
 806         if (readlink(linkname, filename, size - 1) < 0)
 807                 goto out_free;
 808
 809         if (unlink(linkname))
 810                 goto out_free;
 811
 812         /*
 813          * Since the link is relative, we must make it absolute:
 814          */
 815         tmp = strrchr(linkname, '/') + 1;
 816         snprintf(tmp, size - (tmp - linkname), "%s", filename);
 817
 818         if (rm_rf(linkname))
 819                 goto out_free;
 820
 821         err = 0;
 822 out_free:
 823         free(filename);
 824         free(linkname);
 825         return err;
 826 }
 827
 828 static int filename__read_build_id_ns(const char *filename,
 829                                       struct build_id *bid,
 830                                       struct nsinfo *nsi)
 831 {
 832         struct nscookie nsc;
 833         int ret;
 834
 835         nsinfo__mountns_enter(nsi, &nsc);
 836         ret = filename__read_build_id(filename, bid);
 837         nsinfo__mountns_exit(&nsc);
 838
 839         return ret;
 840 }
 841
 842 static bool dso__build_id_mismatch(struct dso *dso, const char *name)
 843 {
 844         struct build_id bid;
 845         bool ret = false;
 846
 847         mutex_lock(dso__lock(dso));
 848         if (filename__read_build_id_ns(name, &bid, dso__nsinfo(dso)) >= 0)
 849                 ret = !dso__build_id_equal(dso, &bid);
 850
 851         mutex_unlock(dso__lock(dso));
 852
 853         return ret;
 854 }
 855
 856 static int dso__cache_build_id(struct dso *dso, struct machine *machine,
 857                                void *priv __maybe_unused)
 858 {
 859         bool is_kallsyms = dso__is_kallsyms(dso);
 860         bool is_vdso = dso__is_vdso(dso);
 861         const char *name = dso__long_name(dso);
 862         const char *proper_name = NULL;
 863         const char *root_dir = NULL;
 864         char *allocated_name = NULL;
 865         int ret = 0;
 866
 867         if (!dso__has_build_id(dso))
 868                 return 0;
 869
 870         if (dso__is_kcore(dso)) {
 871                 is_kallsyms = true;
 872                 name = machine->mmap_name;
 873         }
 874
 875         if (!machine__is_host(machine)) {
 876                 if (*machine->root_dir) {
 877                         root_dir = machine->root_dir;
 878                         ret = asprintf(&allocated_name, "%s/%s", root_dir, name);
 879                         if (ret < 0)
 880                                 return ret;
 881                         proper_name = name;
 882                         name = allocated_name;
 883                 } else if (is_kallsyms) {
 884                         /* Cannot get guest kallsyms */
 885                         return 0;
 886                 }
 887         }
 888
 889         if (!is_kallsyms && dso__build_id_mismatch(dso, name))
 890                 goto out_free;
 891
 892         mutex_lock(dso__lock(dso));
 893         ret = build_id_cache__add_b(dso__bid(dso), name, dso__nsinfo(dso),
 894                                     is_kallsyms, is_vdso, proper_name, root_dir);
 895         mutex_unlock(dso__lock(dso));
 896 out_free:
 897         free(allocated_name);
 898         return ret;
 899 }
 900
 901 static int
 902 machines__for_each_dso(struct machines *machines, machine__dso_t fn, void *priv)
 903 {
 904         int ret = machine__for_each_dso(&machines->host, fn, priv);
 905         struct rb_node *nd;
 906
 907         for (nd = rb_first_cached(&machines->guests); nd;
 908              nd = rb_next(nd)) {
 909                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 910
 911                 ret |= machine__for_each_dso(pos, fn, priv);
 912         }
 913         return ret ? -1 : 0;
 914 }
 915
 916 int __perf_session__cache_build_ids(struct perf_session *session,
 917                                     machine__dso_t fn, void *priv)
 918 {
 919         if (no_buildid_cache)
 920                 return 0;
 921
 922         if (mkdir(buildid_dir, 0755) != 0 && errno != EEXIST)
 923                 return -1;
 924
 925         return machines__for_each_dso(&session->machines, fn, priv) ?  -1 : 0;
 926 }
 927
 928 int perf_session__cache_build_ids(struct perf_session *session)
 929 {
 930         return __perf_session__cache_build_ids(session, dso__cache_build_id, NULL);
 931 }
 932
 933 static bool machine__read_build_ids(struct machine *machine, bool with_hits)
 934 {
 935         return dsos__read_build_ids(&machine->dsos, with_hits);
 936 }
 937
 938 bool perf_session__read_build_ids(struct perf_session *session, bool with_hits)
 939 {
 940         struct rb_node *nd;
 941         bool ret = machine__read_build_ids(&session->machines.host, with_hits);
 942
 943         for (nd = rb_first_cached(&session->machines.guests); nd;
 944              nd = rb_next(nd)) {
 945                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 946                 ret |= machine__read_build_ids(pos, with_hits);
 947         }
 948
 949         return ret;
 950 }
 951
 952 void build_id__init(struct build_id *bid, const u8 *data, size_t size)
 953 {
 954         WARN_ON(size > BUILD_ID_SIZE);
 955         memcpy(bid->data, data, size);
 956         bid->size = size;
 957 }
 958
 959 bool build_id__is_defined(const struct build_id *bid)
 960 {
 961         return bid && bid->size ? !!memchr_inv(bid->data, 0, bid->size) : false;
 962 }