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(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                 map__dso(al.map)->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, bool is_kallsyms)
 266 {
 267         bool is_vdso = dso__is_vdso((struct dso *)dso);
 268         char sbuild_id[SBUILD_ID_SIZE];
 269         char *linkname;
 270         bool alloc = (bf == NULL);
 271         int ret;
 272
 273         if (!dso->has_build_id)
 274                 return NULL;
 275
 276         build_id__sprintf(&dso->bid, sbuild_id);
 277         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 278         if (!linkname)
 279                 return NULL;
 280
 281         /* Check if old style build_id cache */
 282         if (is_regular_file(linkname))
 283                 ret = asnprintf(&bf, size, "%s", linkname);
 284         else
 285                 ret = asnprintf(&bf, size, "%s/%s", linkname,
 286                          build_id_cache__basename(is_kallsyms, is_vdso,
 287                                                   is_debug));
 288         if (ret < 0 || (!alloc && size < (unsigned int)ret))
 289                 bf = NULL;
 290         free(linkname);
 291
 292         return bf;
 293 }
 294
 295 char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
 296                              bool is_debug)
 297 {
 298         bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
 299
 300         return __dso__build_id_filename(dso, bf, size, is_debug, is_kallsyms);
 301 }
 302
 303 static int write_buildid(const char *name, size_t name_len, struct build_id *bid,
 304                          pid_t pid, u16 misc, struct feat_fd *fd)
 305 {
 306         int err;
 307         struct perf_record_header_build_id b;
 308         size_t len;
 309
 310         len = name_len + 1;
 311         len = PERF_ALIGN(len, NAME_ALIGN);
 312
 313         memset(&b, 0, sizeof(b));
 314         memcpy(&b.data, bid->data, bid->size);
 315         b.size = (u8) bid->size;
 316         misc |= PERF_RECORD_MISC_BUILD_ID_SIZE;
 317         b.pid = pid;
 318         b.header.misc = misc;
 319         b.header.size = sizeof(b) + len;
 320
 321         err = do_write(fd, &b, sizeof(b));
 322         if (err < 0)
 323                 return err;
 324
 325         return write_padded(fd, name, name_len + 1, len);
 326 }
 327
 328 static int machine__write_buildid_table(struct machine *machine,
 329                                         struct feat_fd *fd)
 330 {
 331         int err = 0;
 332         struct dso *pos;
 333         u16 kmisc = PERF_RECORD_MISC_KERNEL,
 334             umisc = PERF_RECORD_MISC_USER;
 335
 336         if (!machine__is_host(machine)) {
 337                 kmisc = PERF_RECORD_MISC_GUEST_KERNEL;
 338                 umisc = PERF_RECORD_MISC_GUEST_USER;
 339         }
 340
 341         dsos__for_each_with_build_id(pos, &machine->dsos.head) {
 342                 const char *name;
 343                 size_t name_len;
 344                 bool in_kernel = false;
 345
 346                 if (!pos->hit && !dso__is_vdso(pos))
 347                         continue;
 348
 349                 if (dso__is_vdso(pos)) {
 350                         name = pos->short_name;
 351                         name_len = pos->short_name_len;
 352                 } else if (dso__is_kcore(pos)) {
 353                         name = machine->mmap_name;
 354                         name_len = strlen(name);
 355                 } else {
 356                         name = pos->long_name;
 357                         name_len = pos->long_name_len;
 358                 }
 359
 360                 in_kernel = pos->kernel ||
 361                                 is_kernel_module(name,
 362                                         PERF_RECORD_MISC_CPUMODE_UNKNOWN);
 363                 err = write_buildid(name, name_len, &pos->bid, machine->pid,
 364                                     in_kernel ? kmisc : umisc, fd);
 365                 if (err)
 366                         break;
 367         }
 368
 369         return err;
 370 }
 371
 372 int perf_session__write_buildid_table(struct perf_session *session,
 373                                       struct feat_fd *fd)
 374 {
 375         struct rb_node *nd;
 376         int err = machine__write_buildid_table(&session->machines.host, fd);
 377
 378         if (err)
 379                 return err;
 380
 381         for (nd = rb_first_cached(&session->machines.guests); nd;
 382              nd = rb_next(nd)) {
 383                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 384                 err = machine__write_buildid_table(pos, fd);
 385                 if (err)
 386                         break;
 387         }
 388         return err;
 389 }
 390
 391 static int __dsos__hit_all(struct list_head *head)
 392 {
 393         struct dso *pos;
 394
 395         list_for_each_entry(pos, head, node)
 396                 pos->hit = true;
 397
 398         return 0;
 399 }
 400
 401 static int machine__hit_all_dsos(struct machine *machine)
 402 {
 403         return __dsos__hit_all(&machine->dsos.head);
 404 }
 405
 406 int dsos__hit_all(struct perf_session *session)
 407 {
 408         struct rb_node *nd;
 409         int err;
 410
 411         err = machine__hit_all_dsos(&session->machines.host);
 412         if (err)
 413                 return err;
 414
 415         for (nd = rb_first_cached(&session->machines.guests); nd;
 416              nd = rb_next(nd)) {
 417                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 418
 419                 err = machine__hit_all_dsos(pos);
 420                 if (err)
 421                         return err;
 422         }
 423
 424         return 0;
 425 }
 426
 427 void disable_buildid_cache(void)
 428 {
 429         no_buildid_cache = true;
 430 }
 431
 432 static bool lsdir_bid_head_filter(const char *name __maybe_unused,
 433                                   struct dirent *d)
 434 {
 435         return (strlen(d->d_name) == 2) &&
 436                 isxdigit(d->d_name[0]) && isxdigit(d->d_name[1]);
 437 }
 438
 439 static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
 440                                   struct dirent *d)
 441 {
 442         int i = 0;
 443         while (isxdigit(d->d_name[i]) && i < SBUILD_ID_SIZE - 3)
 444                 i++;
 445         return (i >= SBUILD_ID_MIN_SIZE - 3) && (i <= SBUILD_ID_SIZE - 3) &&
 446                 (d->d_name[i] == '\0');
 447 }
 448
 449 struct strlist *build_id_cache__list_all(bool validonly)
 450 {
 451         struct strlist *toplist, *linklist = NULL, *bidlist;
 452         struct str_node *nd, *nd2;
 453         char *topdir, *linkdir = NULL;
 454         char sbuild_id[SBUILD_ID_SIZE];
 455
 456         /* for filename__ functions */
 457         if (validonly)
 458                 symbol__init(NULL);
 459
 460         /* Open the top-level directory */
 461         if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
 462                 return NULL;
 463
 464         bidlist = strlist__new(NULL, NULL);
 465         if (!bidlist)
 466                 goto out;
 467
 468         toplist = lsdir(topdir, lsdir_bid_head_filter);
 469         if (!toplist) {
 470                 pr_debug("Error in lsdir(%s): %d\n", topdir, errno);
 471                 /* If there is no buildid cache, return an empty list */
 472                 if (errno == ENOENT)
 473                         goto out;
 474                 goto err_out;
 475         }
 476
 477         strlist__for_each_entry(nd, toplist) {
 478                 if (asprintf(&linkdir, "%s/%s", topdir, nd->s) < 0)
 479                         goto err_out;
 480                 /* Open the lower-level directory */
 481                 linklist = lsdir(linkdir, lsdir_bid_tail_filter);
 482                 if (!linklist) {
 483                         pr_debug("Error in lsdir(%s): %d\n", linkdir, errno);
 484                         goto err_out;
 485                 }
 486                 strlist__for_each_entry(nd2, linklist) {
 487                         if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
 488                                      nd->s, nd2->s) > SBUILD_ID_SIZE - 1)
 489                                 goto err_out;
 490                         if (validonly && !build_id_cache__valid_id(sbuild_id))
 491                                 continue;
 492                         if (strlist__add(bidlist, sbuild_id) < 0)
 493                                 goto err_out;
 494                 }
 495                 strlist__delete(linklist);
 496                 zfree(&linkdir);
 497         }
 498
 499 out_free:
 500         strlist__delete(toplist);
 501 out:
 502         free(topdir);
 503
 504         return bidlist;
 505
 506 err_out:
 507         strlist__delete(linklist);
 508         zfree(&linkdir);
 509         strlist__delete(bidlist);
 510         bidlist = NULL;
 511         goto out_free;
 512 }
 513
 514 static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)
 515 {
 516         size_t i;
 517
 518         for (i = 0; i < len; i++) {
 519                 if (!isxdigit(maybe_sbuild_id[i]))
 520                         return false;
 521         }
 522         return true;
 523 }
 524
 525 /* Return the valid complete build-id */
 526 char *build_id_cache__complement(const char *incomplete_sbuild_id)
 527 {
 528         struct strlist *bidlist;
 529         struct str_node *nd, *cand = NULL;
 530         char *sbuild_id = NULL;
 531         size_t len = strlen(incomplete_sbuild_id);
 532
 533         if (len >= SBUILD_ID_SIZE ||
 534             !str_is_build_id(incomplete_sbuild_id, len))
 535                 return NULL;
 536
 537         bidlist = build_id_cache__list_all(true);
 538         if (!bidlist)
 539                 return NULL;
 540
 541         strlist__for_each_entry(nd, bidlist) {
 542                 if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)
 543                         continue;
 544                 if (cand) {     /* Error: There are more than 2 candidates. */
 545                         cand = NULL;
 546                         break;
 547                 }
 548                 cand = nd;
 549         }
 550         if (cand)
 551                 sbuild_id = strdup(cand->s);
 552         strlist__delete(bidlist);
 553
 554         return sbuild_id;
 555 }
 556
 557 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
 558                                struct nsinfo *nsi, bool is_kallsyms,
 559                                bool is_vdso)
 560 {
 561         char *realname = (char *)name, *filename;
 562         bool slash = is_kallsyms || is_vdso;
 563
 564         if (!slash)
 565                 realname = nsinfo__realpath(name, nsi);
 566
 567         if (asprintf(&filename, "%s%s%s%s%s", buildid_dir, slash ? "/" : "",
 568                      is_vdso ? DSO__NAME_VDSO : (realname ? realname : name),
 569                      sbuild_id ? "/" : "", sbuild_id ?: "") < 0)
 570                 filename = NULL;
 571
 572         if (!slash)
 573                 free(realname);
 574
 575         return filename;
 576 }
 577
 578 int build_id_cache__list_build_ids(const char *pathname, struct nsinfo *nsi,
 579                                    struct strlist **result)
 580 {
 581         char *dir_name;
 582         int ret = 0;
 583
 584         dir_name = build_id_cache__cachedir(NULL, pathname, nsi, false, false);
 585         if (!dir_name)
 586                 return -ENOMEM;
 587
 588         *result = lsdir(dir_name, lsdir_no_dot_filter);
 589         if (!*result)
 590                 ret = -errno;
 591         free(dir_name);
 592
 593         return ret;
 594 }
 595
 596 #if defined(HAVE_LIBELF_SUPPORT) && defined(HAVE_GELF_GETNOTE_SUPPORT)
 597 static int build_id_cache__add_sdt_cache(const char *sbuild_id,
 598                                           const char *realname,
 599                                           struct nsinfo *nsi)
 600 {
 601         struct probe_cache *cache;
 602         int ret;
 603         struct nscookie nsc;
 604
 605         cache = probe_cache__new(sbuild_id, nsi);
 606         if (!cache)
 607                 return -1;
 608
 609         nsinfo__mountns_enter(nsi, &nsc);
 610         ret = probe_cache__scan_sdt(cache, realname);
 611         nsinfo__mountns_exit(&nsc);
 612         if (ret >= 0) {
 613                 pr_debug4("Found %d SDTs in %s\n", ret, realname);
 614                 if (probe_cache__commit(cache) < 0)
 615                         ret = -1;
 616         }
 617         probe_cache__delete(cache);
 618         return ret;
 619 }
 620 #else
 621 #define build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) (0)
 622 #endif
 623
 624 static char *build_id_cache__find_debug(const char *sbuild_id,
 625                                         struct nsinfo *nsi,
 626                                         const char *root_dir)
 627 {
 628         const char *dirname = "/usr/lib/debug/.build-id/";
 629         char *realname = NULL;
 630         char dirbuf[PATH_MAX];
 631         char *debugfile;
 632         struct nscookie nsc;
 633         size_t len = 0;
 634
 635         debugfile = calloc(1, PATH_MAX);
 636         if (!debugfile)
 637                 goto out;
 638
 639         if (root_dir) {
 640                 path__join(dirbuf, PATH_MAX, root_dir, dirname);
 641                 dirname = dirbuf;
 642         }
 643
 644         len = __symbol__join_symfs(debugfile, PATH_MAX, dirname);
 645         snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,
 646                  sbuild_id + 2);
 647
 648         nsinfo__mountns_enter(nsi, &nsc);
 649         realname = realpath(debugfile, NULL);
 650         if (realname && access(realname, R_OK))
 651                 zfree(&realname);
 652         nsinfo__mountns_exit(&nsc);
 653
 654 #ifdef HAVE_DEBUGINFOD_SUPPORT
 655         if (realname == NULL) {
 656                 debuginfod_client* c;
 657
 658                 pr_debug("Downloading debug info with build id %s\n", sbuild_id);
 659
 660                 c = debuginfod_begin();
 661                 if (c != NULL) {
 662                         int fd = debuginfod_find_debuginfo(c,
 663                                         (const unsigned char*)sbuild_id, 0,
 664                                         &realname);
 665                         if (fd >= 0)
 666                                 close(fd); /* retaining reference by realname */
 667                         debuginfod_end(c);
 668                 }
 669         }
 670 #endif
 671
 672 out:
 673         free(debugfile);
 674         return realname;
 675 }
 676
 677 int
 678 build_id_cache__add(const char *sbuild_id, const char *name, const char *realname,
 679                     struct nsinfo *nsi, bool is_kallsyms, bool is_vdso,
 680                     const char *proper_name, const char *root_dir)
 681 {
 682         const size_t size = PATH_MAX;
 683         char *filename = NULL, *dir_name = NULL, *linkname = zalloc(size), *tmp;
 684         char *debugfile = NULL;
 685         int err = -1;
 686
 687         if (!proper_name)
 688                 proper_name = name;
 689
 690         dir_name = build_id_cache__cachedir(sbuild_id, proper_name, nsi, is_kallsyms,
 691                                             is_vdso);
 692         if (!dir_name)
 693                 goto out_free;
 694
 695         /* Remove old style build-id cache */
 696         if (is_regular_file(dir_name))
 697                 if (unlink(dir_name))
 698                         goto out_free;
 699
 700         if (mkdir_p(dir_name, 0755))
 701                 goto out_free;
 702
 703         /* Save the allocated buildid dirname */
 704         if (asprintf(&filename, "%s/%s", dir_name,
 705                      build_id_cache__basename(is_kallsyms, is_vdso,
 706                      false)) < 0) {
 707                 filename = NULL;
 708                 goto out_free;
 709         }
 710
 711         if (access(filename, F_OK)) {
 712                 if (is_kallsyms) {
 713                         if (copyfile("/proc/kallsyms", filename))
 714                                 goto out_free;
 715                 } else if (nsi && nsinfo__need_setns(nsi)) {
 716                         if (copyfile_ns(name, filename, nsi))
 717                                 goto out_free;
 718                 } else if (link(realname, filename) && errno != EEXIST) {
 719                         struct stat f_stat;
 720
 721                         if (!(stat(name, &f_stat) < 0) &&
 722                                         copyfile_mode(name, filename, f_stat.st_mode))
 723                                 goto out_free;
 724                 }
 725         }
 726
 727         /* Some binaries are stripped, but have .debug files with their symbol
 728          * table.  Check to see if we can locate one of those, since the elf
 729          * file itself may not be very useful to users of our tools without a
 730          * symtab.
 731          */
 732         if (!is_kallsyms && !is_vdso &&
 733             strncmp(".ko", name + strlen(name) - 3, 3)) {
 734                 debugfile = build_id_cache__find_debug(sbuild_id, nsi, root_dir);
 735                 if (debugfile) {
 736                         zfree(&filename);
 737                         if (asprintf(&filename, "%s/%s", dir_name,
 738                             build_id_cache__basename(false, false, true)) < 0) {
 739                                 filename = NULL;
 740                                 goto out_free;
 741                         }
 742                         if (access(filename, F_OK)) {
 743                                 if (nsi && nsinfo__need_setns(nsi)) {
 744                                         if (copyfile_ns(debugfile, filename,
 745                                                         nsi))
 746                                                 goto out_free;
 747                                 } else if (link(debugfile, filename) &&
 748                                                 errno != EEXIST &&
 749                                                 copyfile(debugfile, filename))
 750                                         goto out_free;
 751                         }
 752                 }
 753         }
 754
 755         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 756                 goto out_free;
 757         tmp = strrchr(linkname, '/');
 758         *tmp = '\0';
 759
 760         if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
 761                 goto out_free;
 762
 763         *tmp = '/';
 764         tmp = dir_name + strlen(buildid_dir) - 5;
 765         memcpy(tmp, "../..", 5);
 766
 767         if (symlink(tmp, linkname) == 0) {
 768                 err = 0;
 769         } else if (errno == EEXIST) {
 770                 char path[PATH_MAX];
 771                 ssize_t len;
 772
 773                 len = readlink(linkname, path, sizeof(path) - 1);
 774                 if (len <= 0) {
 775                         pr_err("Can't read link: %s\n", linkname);
 776                         goto out_free;
 777                 }
 778                 path[len] = '\0';
 779
 780                 if (strcmp(tmp, path)) {
 781                         pr_debug("build <%s> already linked to %s\n",
 782                                  sbuild_id, linkname);
 783                 }
 784                 err = 0;
 785         }
 786
 787         /* Update SDT cache : error is just warned */
 788         if (realname &&
 789             build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) < 0)
 790                 pr_debug4("Failed to update/scan SDT cache for %s\n", realname);
 791
 792 out_free:
 793         free(filename);
 794         free(debugfile);
 795         free(dir_name);
 796         free(linkname);
 797         return err;
 798 }
 799
 800 int __build_id_cache__add_s(const char *sbuild_id, const char *name,
 801                             struct nsinfo *nsi, bool is_kallsyms, bool is_vdso,
 802                             const char *proper_name, const char *root_dir)
 803 {
 804         char *realname = NULL;
 805         int err = -1;
 806
 807         if (!is_kallsyms) {
 808                 if (!is_vdso)
 809                         realname = nsinfo__realpath(name, nsi);
 810                 else
 811                         realname = realpath(name, NULL);
 812                 if (!realname)
 813                         goto out_free;
 814         }
 815
 816         err = build_id_cache__add(sbuild_id, name, realname, nsi,
 817                                   is_kallsyms, is_vdso, proper_name, root_dir);
 818 out_free:
 819         if (!is_kallsyms)
 820                 free(realname);
 821         return err;
 822 }
 823
 824 static int build_id_cache__add_b(const struct build_id *bid,
 825                                  const char *name, struct nsinfo *nsi,
 826                                  bool is_kallsyms, bool is_vdso,
 827                                  const char *proper_name,
 828                                  const char *root_dir)
 829 {
 830         char sbuild_id[SBUILD_ID_SIZE];
 831
 832         build_id__sprintf(bid, sbuild_id);
 833
 834         return __build_id_cache__add_s(sbuild_id, name, nsi, is_kallsyms,
 835                                        is_vdso, proper_name, root_dir);
 836 }
 837
 838 bool build_id_cache__cached(const char *sbuild_id)
 839 {
 840         bool ret = false;
 841         char *filename = build_id_cache__linkname(sbuild_id, NULL, 0);
 842
 843         if (filename && !access(filename, F_OK))
 844                 ret = true;
 845         free(filename);
 846
 847         return ret;
 848 }
 849
 850 int build_id_cache__remove_s(const char *sbuild_id)
 851 {
 852         const size_t size = PATH_MAX;
 853         char *filename = zalloc(size),
 854              *linkname = zalloc(size), *tmp;
 855         int err = -1;
 856
 857         if (filename == NULL || linkname == NULL)
 858                 goto out_free;
 859
 860         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 861                 goto out_free;
 862
 863         if (access(linkname, F_OK))
 864                 goto out_free;
 865
 866         if (readlink(linkname, filename, size - 1) < 0)
 867                 goto out_free;
 868
 869         if (unlink(linkname))
 870                 goto out_free;
 871
 872         /*
 873          * Since the link is relative, we must make it absolute:
 874          */
 875         tmp = strrchr(linkname, '/') + 1;
 876         snprintf(tmp, size - (tmp - linkname), "%s", filename);
 877
 878         if (rm_rf(linkname))
 879                 goto out_free;
 880
 881         err = 0;
 882 out_free:
 883         free(filename);
 884         free(linkname);
 885         return err;
 886 }
 887
 888 static int filename__read_build_id_ns(const char *filename,
 889                                       struct build_id *bid,
 890                                       struct nsinfo *nsi)
 891 {
 892         struct nscookie nsc;
 893         int ret;
 894
 895         nsinfo__mountns_enter(nsi, &nsc);
 896         ret = filename__read_build_id(filename, bid);
 897         nsinfo__mountns_exit(&nsc);
 898
 899         return ret;
 900 }
 901
 902 static bool dso__build_id_mismatch(struct dso *dso, const char *name)
 903 {
 904         struct build_id bid;
 905         bool ret = false;
 906
 907         mutex_lock(&dso->lock);
 908         if (filename__read_build_id_ns(name, &bid, dso->nsinfo) >= 0)
 909                 ret = !dso__build_id_equal(dso, &bid);
 910
 911         mutex_unlock(&dso->lock);
 912
 913         return ret;
 914 }
 915
 916 static int dso__cache_build_id(struct dso *dso, struct machine *machine,
 917                                void *priv __maybe_unused)
 918 {
 919         bool is_kallsyms = dso__is_kallsyms(dso);
 920         bool is_vdso = dso__is_vdso(dso);
 921         const char *name = dso->long_name;
 922         const char *proper_name = NULL;
 923         const char *root_dir = NULL;
 924         char *allocated_name = NULL;
 925         int ret = 0;
 926
 927         if (!dso->has_build_id)
 928                 return 0;
 929
 930         if (dso__is_kcore(dso)) {
 931                 is_kallsyms = true;
 932                 name = machine->mmap_name;
 933         }
 934
 935         if (!machine__is_host(machine)) {
 936                 if (*machine->root_dir) {
 937                         root_dir = machine->root_dir;
 938                         ret = asprintf(&allocated_name, "%s/%s", root_dir, name);
 939                         if (ret < 0)
 940                                 return ret;
 941                         proper_name = name;
 942                         name = allocated_name;
 943                 } else if (is_kallsyms) {
 944                         /* Cannot get guest kallsyms */
 945                         return 0;
 946                 }
 947         }
 948
 949         if (!is_kallsyms && dso__build_id_mismatch(dso, name))
 950                 goto out_free;
 951
 952         mutex_lock(&dso->lock);
 953         ret = build_id_cache__add_b(&dso->bid, name, dso->nsinfo,
 954                                     is_kallsyms, is_vdso, proper_name, root_dir);
 955         mutex_unlock(&dso->lock);
 956 out_free:
 957         free(allocated_name);
 958         return ret;
 959 }
 960
 961 static int
 962 machines__for_each_dso(struct machines *machines, machine__dso_t fn, void *priv)
 963 {
 964         int ret = machine__for_each_dso(&machines->host, fn, priv);
 965         struct rb_node *nd;
 966
 967         for (nd = rb_first_cached(&machines->guests); nd;
 968              nd = rb_next(nd)) {
 969                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 970
 971                 ret |= machine__for_each_dso(pos, fn, priv);
 972         }
 973         return ret ? -1 : 0;
 974 }
 975
 976 int __perf_session__cache_build_ids(struct perf_session *session,
 977                                     machine__dso_t fn, void *priv)
 978 {
 979         if (no_buildid_cache)
 980                 return 0;
 981
 982         if (mkdir(buildid_dir, 0755) != 0 && errno != EEXIST)
 983                 return -1;
 984
 985         return machines__for_each_dso(&session->machines, fn, priv) ?  -1 : 0;
 986 }
 987
 988 int perf_session__cache_build_ids(struct perf_session *session)
 989 {
 990         return __perf_session__cache_build_ids(session, dso__cache_build_id, NULL);
 991 }
 992
 993 static bool machine__read_build_ids(struct machine *machine, bool with_hits)
 994 {
 995         return __dsos__read_build_ids(&machine->dsos.head, with_hits);
 996 }
 997
 998 bool perf_session__read_build_ids(struct perf_session *session, bool with_hits)
 999 {
1000         struct rb_node *nd;
1001         bool ret = machine__read_build_ids(&session->machines.host, with_hits);
1002
1003         for (nd = rb_first_cached(&session->machines.guests); nd;
1004              nd = rb_next(nd)) {
1005                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
1006                 ret |= machine__read_build_ids(pos, with_hits);
1007         }
1008
1009         return ret;
1010 }
1011
1012 void build_id__init(struct build_id *bid, const u8 *data, size_t size)
1013 {
1014         WARN_ON(size > BUILD_ID_SIZE);
1015         memcpy(bid->data, data, size);
1016         bid->size = size;
1017 }
1018
1019 bool build_id__is_defined(const struct build_id *bid)
1020 {
1021         return bid && bid->size ? !!memchr_inv(bid->data, 0, bid->size) : false;
1022 }