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 <asm/bug.h>
  41
  42 static bool no_buildid_cache;
  43
  44 int build_id__mark_dso_hit(struct perf_tool *tool __maybe_unused,
  45                            union perf_event *event,
  46                            struct perf_sample *sample,
  47                            struct evsel *evsel __maybe_unused,
  48                            struct machine *machine)
  49 {
  50         struct addr_location al;
  51         struct thread *thread = machine__findnew_thread(machine, sample->pid,
  52                                                         sample->tid);
  53
  54         if (thread == NULL) {
  55                 pr_err("problem processing %d event, skipping it.\n",
  56                         event->header.type);
  57                 return -1;
  58         }
  59
  60         if (thread__find_map(thread, sample->cpumode, sample->ip, &al))
  61                 al.map->dso->hit = 1;
  62
  63         thread__put(thread);
  64         return 0;
  65 }
  66
  67 static int perf_event__exit_del_thread(struct perf_tool *tool __maybe_unused,
  68                                        union perf_event *event,
  69                                        struct perf_sample *sample
  70                                        __maybe_unused,
  71                                        struct machine *machine)
  72 {
  73         struct thread *thread = machine__findnew_thread(machine,
  74                                                         event->fork.pid,
  75                                                         event->fork.tid);
  76
  77         dump_printf("(%d:%d):(%d:%d)\n", event->fork.pid, event->fork.tid,
  78                     event->fork.ppid, event->fork.ptid);
  79
  80         if (thread) {
  81                 machine__remove_thread(machine, thread);
  82                 thread__put(thread);
  83         }
  84
  85         return 0;
  86 }
  87
  88 struct perf_tool build_id__mark_dso_hit_ops = {
  89         .sample = build_id__mark_dso_hit,
  90         .mmap   = perf_event__process_mmap,
  91         .mmap2  = perf_event__process_mmap2,
  92         .fork   = perf_event__process_fork,
  93         .exit   = perf_event__exit_del_thread,
  94         .attr            = perf_event__process_attr,
  95         .build_id        = perf_event__process_build_id,
  96         .ordered_events  = true,
  97 };
  98
  99 int build_id__sprintf(const struct build_id *build_id, char *bf)
 100 {
 101         char *bid = bf;
 102         const u8 *raw = build_id->data;
 103         size_t i;
 104
 105         for (i = 0; i < build_id->size; ++i) {
 106                 sprintf(bid, "%02x", *raw);
 107                 ++raw;
 108                 bid += 2;
 109         }
 110
 111         return (bid - bf) + 1;
 112 }
 113
 114 int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id)
 115 {
 116         char notes[PATH_MAX];
 117         struct build_id bid;
 118         int ret;
 119
 120         if (!root_dir)
 121                 root_dir = "";
 122
 123         scnprintf(notes, sizeof(notes), "%s/sys/kernel/notes", root_dir);
 124
 125         ret = sysfs__read_build_id(notes, &bid);
 126         if (ret < 0)
 127                 return ret;
 128
 129         return build_id__sprintf(&bid, sbuild_id);
 130 }
 131
 132 int filename__sprintf_build_id(const char *pathname, char *sbuild_id)
 133 {
 134         struct build_id bid;
 135         int ret;
 136
 137         ret = filename__read_build_id(pathname, &bid);
 138         if (ret < 0)
 139                 return ret;
 140
 141         return build_id__sprintf(&bid, sbuild_id);
 142 }
 143
 144 /* asnprintf consolidates asprintf and snprintf */
 145 static int asnprintf(char **strp, size_t size, const char *fmt, ...)
 146 {
 147         va_list ap;
 148         int ret;
 149
 150         if (!strp)
 151                 return -EINVAL;
 152
 153         va_start(ap, fmt);
 154         if (*strp)
 155                 ret = vsnprintf(*strp, size, fmt, ap);
 156         else
 157                 ret = vasprintf(strp, fmt, ap);
 158         va_end(ap);
 159
 160         return ret;
 161 }
 162
 163 char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
 164                                     size_t size)
 165 {
 166         bool retry_old = true;
 167
 168         snprintf(bf, size, "%s/%s/%s/kallsyms",
 169                  buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
 170 retry:
 171         if (!access(bf, F_OK))
 172                 return bf;
 173         if (retry_old) {
 174                 /* Try old style kallsyms cache */
 175                 snprintf(bf, size, "%s/%s/%s",
 176                          buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
 177                 retry_old = false;
 178                 goto retry;
 179         }
 180
 181         return NULL;
 182 }
 183
 184 char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size)
 185 {
 186         char *tmp = bf;
 187         int ret = asnprintf(&bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
 188                             sbuild_id, sbuild_id + 2);
 189         if (ret < 0 || (tmp && size < (unsigned int)ret))
 190                 return NULL;
 191         return bf;
 192 }
 193
 194 /* The caller is responsible to free the returned buffer. */
 195 char *build_id_cache__origname(const char *sbuild_id)
 196 {
 197         char *linkname;
 198         char buf[PATH_MAX];
 199         char *ret = NULL, *p;
 200         size_t offs = 5;        /* == strlen("../..") */
 201         ssize_t len;
 202
 203         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 204         if (!linkname)
 205                 return NULL;
 206
 207         len = readlink(linkname, buf, sizeof(buf) - 1);
 208         if (len <= 0)
 209                 goto out;
 210         buf[len] = '\0';
 211
 212         /* The link should be "../..<origpath>/<sbuild_id>" */
 213         p = strrchr(buf, '/');  /* Cut off the "/<sbuild_id>" */
 214         if (p && (p > buf + offs)) {
 215                 *p = '\0';
 216                 if (buf[offs + 1] == '[')
 217                         offs++; /*
 218                                  * This is a DSO name, like [kernel.kallsyms].
 219                                  * Skip the first '/', since this is not the
 220                                  * cache of a regular file.
 221                                  */
 222                 ret = strdup(buf + offs);       /* Skip "../..[/]" */
 223         }
 224 out:
 225         free(linkname);
 226         return ret;
 227 }
 228
 229 /* Check if the given build_id cache is valid on current running system */
 230 static bool build_id_cache__valid_id(char *sbuild_id)
 231 {
 232         char real_sbuild_id[SBUILD_ID_SIZE] = "";
 233         char *pathname;
 234         int ret = 0;
 235         bool result = false;
 236
 237         pathname = build_id_cache__origname(sbuild_id);
 238         if (!pathname)
 239                 return false;
 240
 241         if (!strcmp(pathname, DSO__NAME_KALLSYMS))
 242                 ret = sysfs__sprintf_build_id("/", real_sbuild_id);
 243         else if (pathname[0] == '/')
 244                 ret = filename__sprintf_build_id(pathname, real_sbuild_id);
 245         else
 246                 ret = -EINVAL;  /* Should we support other special DSO cache? */
 247         if (ret >= 0)
 248                 result = (strcmp(sbuild_id, real_sbuild_id) == 0);
 249         free(pathname);
 250
 251         return result;
 252 }
 253
 254 static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso,
 255                                             bool is_debug)
 256 {
 257         return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : (is_debug ?
 258             "debug" : "elf"));
 259 }
 260
 261 char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
 262                              bool is_debug)
 263 {
 264         bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
 265         bool is_vdso = dso__is_vdso((struct dso *)dso);
 266         char sbuild_id[SBUILD_ID_SIZE];
 267         char *linkname;
 268         bool alloc = (bf == NULL);
 269         int ret;
 270
 271         if (!dso->has_build_id)
 272                 return NULL;
 273
 274         build_id__sprintf(&dso->bid, sbuild_id);
 275         linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
 276         if (!linkname)
 277                 return NULL;
 278
 279         /* Check if old style build_id cache */
 280         if (is_regular_file(linkname))
 281                 ret = asnprintf(&bf, size, "%s", linkname);
 282         else
 283                 ret = asnprintf(&bf, size, "%s/%s", linkname,
 284                          build_id_cache__basename(is_kallsyms, is_vdso,
 285                                                   is_debug));
 286         if (ret < 0 || (!alloc && size < (unsigned int)ret))
 287                 bf = NULL;
 288         free(linkname);
 289
 290         return bf;
 291 }
 292
 293 #define dsos__for_each_with_build_id(pos, head) \
 294         list_for_each_entry(pos, head, node)    \
 295                 if (!pos->has_build_id)         \
 296                         continue;               \
 297                 else
 298
 299 static int write_buildid(const char *name, size_t name_len, struct build_id *bid,
 300                          pid_t pid, u16 misc, struct feat_fd *fd)
 301 {
 302         int err;
 303         struct perf_record_header_build_id b;
 304         size_t len;
 305
 306         len = name_len + 1;
 307         len = PERF_ALIGN(len, NAME_ALIGN);
 308
 309         memset(&b, 0, sizeof(b));
 310         memcpy(&b.data, bid->data, bid->size);
 311         b.size = (u8) bid->size;
 312         misc |= PERF_RECORD_MISC_BUILD_ID_SIZE;
 313         b.pid = pid;
 314         b.header.misc = misc;
 315         b.header.size = sizeof(b) + len;
 316
 317         err = do_write(fd, &b, sizeof(b));
 318         if (err < 0)
 319                 return err;
 320
 321         return write_padded(fd, name, name_len + 1, len);
 322 }
 323
 324 static int machine__write_buildid_table(struct machine *machine,
 325                                         struct feat_fd *fd)
 326 {
 327         int err = 0;
 328         struct dso *pos;
 329         u16 kmisc = PERF_RECORD_MISC_KERNEL,
 330             umisc = PERF_RECORD_MISC_USER;
 331
 332         if (!machine__is_host(machine)) {
 333                 kmisc = PERF_RECORD_MISC_GUEST_KERNEL;
 334                 umisc = PERF_RECORD_MISC_GUEST_USER;
 335         }
 336
 337         dsos__for_each_with_build_id(pos, &machine->dsos.head) {
 338                 const char *name;
 339                 size_t name_len;
 340                 bool in_kernel = false;
 341
 342                 if (!pos->hit && !dso__is_vdso(pos))
 343                         continue;
 344
 345                 if (dso__is_vdso(pos)) {
 346                         name = pos->short_name;
 347                         name_len = pos->short_name_len;
 348                 } else if (dso__is_kcore(pos)) {
 349                         name = machine->mmap_name;
 350                         name_len = strlen(name);
 351                 } else {
 352                         name = pos->long_name;
 353                         name_len = pos->long_name_len;
 354                 }
 355
 356                 in_kernel = pos->kernel ||
 357                                 is_kernel_module(name,
 358                                         PERF_RECORD_MISC_CPUMODE_UNKNOWN);
 359                 err = write_buildid(name, name_len, &pos->bid, machine->pid,
 360                                     in_kernel ? kmisc : umisc, fd);
 361                 if (err)
 362                         break;
 363         }
 364
 365         return err;
 366 }
 367
 368 int perf_session__write_buildid_table(struct perf_session *session,
 369                                       struct feat_fd *fd)
 370 {
 371         struct rb_node *nd;
 372         int err = machine__write_buildid_table(&session->machines.host, fd);
 373
 374         if (err)
 375                 return err;
 376
 377         for (nd = rb_first_cached(&session->machines.guests); nd;
 378              nd = rb_next(nd)) {
 379                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 380                 err = machine__write_buildid_table(pos, fd);
 381                 if (err)
 382                         break;
 383         }
 384         return err;
 385 }
 386
 387 static int __dsos__hit_all(struct list_head *head)
 388 {
 389         struct dso *pos;
 390
 391         list_for_each_entry(pos, head, node)
 392                 pos->hit = true;
 393
 394         return 0;
 395 }
 396
 397 static int machine__hit_all_dsos(struct machine *machine)
 398 {
 399         return __dsos__hit_all(&machine->dsos.head);
 400 }
 401
 402 int dsos__hit_all(struct perf_session *session)
 403 {
 404         struct rb_node *nd;
 405         int err;
 406
 407         err = machine__hit_all_dsos(&session->machines.host);
 408         if (err)
 409                 return err;
 410
 411         for (nd = rb_first_cached(&session->machines.guests); nd;
 412              nd = rb_next(nd)) {
 413                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 414
 415                 err = machine__hit_all_dsos(pos);
 416                 if (err)
 417                         return err;
 418         }
 419
 420         return 0;
 421 }
 422
 423 void disable_buildid_cache(void)
 424 {
 425         no_buildid_cache = true;
 426 }
 427
 428 static bool lsdir_bid_head_filter(const char *name __maybe_unused,
 429                                   struct dirent *d)
 430 {
 431         return (strlen(d->d_name) == 2) &&
 432                 isxdigit(d->d_name[0]) && isxdigit(d->d_name[1]);
 433 }
 434
 435 static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
 436                                   struct dirent *d)
 437 {
 438         int i = 0;
 439         while (isxdigit(d->d_name[i]) && i < SBUILD_ID_SIZE - 3)
 440                 i++;
 441         return (i == SBUILD_ID_SIZE - 3) && (d->d_name[i] == '\0');
 442 }
 443
 444 struct strlist *build_id_cache__list_all(bool validonly)
 445 {
 446         struct strlist *toplist, *linklist = NULL, *bidlist;
 447         struct str_node *nd, *nd2;
 448         char *topdir, *linkdir = NULL;
 449         char sbuild_id[SBUILD_ID_SIZE];
 450
 451         /* for filename__ functions */
 452         if (validonly)
 453                 symbol__init(NULL);
 454
 455         /* Open the top-level directory */
 456         if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
 457                 return NULL;
 458
 459         bidlist = strlist__new(NULL, NULL);
 460         if (!bidlist)
 461                 goto out;
 462
 463         toplist = lsdir(topdir, lsdir_bid_head_filter);
 464         if (!toplist) {
 465                 pr_debug("Error in lsdir(%s): %d\n", topdir, errno);
 466                 /* If there is no buildid cache, return an empty list */
 467                 if (errno == ENOENT)
 468                         goto out;
 469                 goto err_out;
 470         }
 471
 472         strlist__for_each_entry(nd, toplist) {
 473                 if (asprintf(&linkdir, "%s/%s", topdir, nd->s) < 0)
 474                         goto err_out;
 475                 /* Open the lower-level directory */
 476                 linklist = lsdir(linkdir, lsdir_bid_tail_filter);
 477                 if (!linklist) {
 478                         pr_debug("Error in lsdir(%s): %d\n", linkdir, errno);
 479                         goto err_out;
 480                 }
 481                 strlist__for_each_entry(nd2, linklist) {
 482                         if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
 483                                      nd->s, nd2->s) != SBUILD_ID_SIZE - 1)
 484                                 goto err_out;
 485                         if (validonly && !build_id_cache__valid_id(sbuild_id))
 486                                 continue;
 487                         if (strlist__add(bidlist, sbuild_id) < 0)
 488                                 goto err_out;
 489                 }
 490                 strlist__delete(linklist);
 491                 zfree(&linkdir);
 492         }
 493
 494 out_free:
 495         strlist__delete(toplist);
 496 out:
 497         free(topdir);
 498
 499         return bidlist;
 500
 501 err_out:
 502         strlist__delete(linklist);
 503         zfree(&linkdir);
 504         strlist__delete(bidlist);
 505         bidlist = NULL;
 506         goto out_free;
 507 }
 508
 509 static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)
 510 {
 511         size_t i;
 512
 513         for (i = 0; i < len; i++) {
 514                 if (!isxdigit(maybe_sbuild_id[i]))
 515                         return false;
 516         }
 517         return true;
 518 }
 519
 520 /* Return the valid complete build-id */
 521 char *build_id_cache__complement(const char *incomplete_sbuild_id)
 522 {
 523         struct strlist *bidlist;
 524         struct str_node *nd, *cand = NULL;
 525         char *sbuild_id = NULL;
 526         size_t len = strlen(incomplete_sbuild_id);
 527
 528         if (len >= SBUILD_ID_SIZE ||
 529             !str_is_build_id(incomplete_sbuild_id, len))
 530                 return NULL;
 531
 532         bidlist = build_id_cache__list_all(true);
 533         if (!bidlist)
 534                 return NULL;
 535
 536         strlist__for_each_entry(nd, bidlist) {
 537                 if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)
 538                         continue;
 539                 if (cand) {     /* Error: There are more than 2 candidates. */
 540                         cand = NULL;
 541                         break;
 542                 }
 543                 cand = nd;
 544         }
 545         if (cand)
 546                 sbuild_id = strdup(cand->s);
 547         strlist__delete(bidlist);
 548
 549         return sbuild_id;
 550 }
 551
 552 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
 553                                struct nsinfo *nsi, bool is_kallsyms,
 554                                bool is_vdso)
 555 {
 556         char *realname = (char *)name, *filename;
 557         bool slash = is_kallsyms || is_vdso;
 558
 559         if (!slash) {
 560                 realname = nsinfo__realpath(name, nsi);
 561                 if (!realname)
 562                         return NULL;
 563         }
 564
 565         if (asprintf(&filename, "%s%s%s%s%s", buildid_dir, slash ? "/" : "",
 566                      is_vdso ? DSO__NAME_VDSO : realname,
 567                      sbuild_id ? "/" : "", sbuild_id ?: "") < 0)
 568                 filename = NULL;
 569
 570         if (!slash)
 571                 free(realname);
 572
 573         return filename;
 574 }
 575
 576 int build_id_cache__list_build_ids(const char *pathname, struct nsinfo *nsi,
 577                                    struct strlist **result)
 578 {
 579         char *dir_name;
 580         int ret = 0;
 581
 582         dir_name = build_id_cache__cachedir(NULL, pathname, nsi, false, false);
 583         if (!dir_name)
 584                 return -ENOMEM;
 585
 586         *result = lsdir(dir_name, lsdir_no_dot_filter);
 587         if (!*result)
 588                 ret = -errno;
 589         free(dir_name);
 590
 591         return ret;
 592 }
 593
 594 #if defined(HAVE_LIBELF_SUPPORT) && defined(HAVE_GELF_GETNOTE_SUPPORT)
 595 static int build_id_cache__add_sdt_cache(const char *sbuild_id,
 596                                           const char *realname,
 597                                           struct nsinfo *nsi)
 598 {
 599         struct probe_cache *cache;
 600         int ret;
 601         struct nscookie nsc;
 602
 603         cache = probe_cache__new(sbuild_id, nsi);
 604         if (!cache)
 605                 return -1;
 606
 607         nsinfo__mountns_enter(nsi, &nsc);
 608         ret = probe_cache__scan_sdt(cache, realname);
 609         nsinfo__mountns_exit(&nsc);
 610         if (ret >= 0) {
 611                 pr_debug4("Found %d SDTs in %s\n", ret, realname);
 612                 if (probe_cache__commit(cache) < 0)
 613                         ret = -1;
 614         }
 615         probe_cache__delete(cache);
 616         return ret;
 617 }
 618 #else
 619 #define build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) (0)
 620 #endif
 621
 622 static char *build_id_cache__find_debug(const char *sbuild_id,
 623                                         struct nsinfo *nsi)
 624 {
 625         char *realname = NULL;
 626         char *debugfile;
 627         struct nscookie nsc;
 628         size_t len = 0;
 629
 630         debugfile = calloc(1, PATH_MAX);
 631         if (!debugfile)
 632                 goto out;
 633
 634         len = __symbol__join_symfs(debugfile, PATH_MAX,
 635                                    "/usr/lib/debug/.build-id/");
 636         snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,
 637                  sbuild_id + 2);
 638
 639         nsinfo__mountns_enter(nsi, &nsc);
 640         realname = realpath(debugfile, NULL);
 641         if (realname && access(realname, R_OK))
 642                 zfree(&realname);
 643         nsinfo__mountns_exit(&nsc);
 644
 645 #ifdef HAVE_DEBUGINFOD_SUPPORT
 646         if (realname == NULL) {
 647                 debuginfod_client* c = debuginfod_begin();
 648                 if (c != NULL) {
 649                         int fd = debuginfod_find_debuginfo(c,
 650                                                            (const unsigned char*)sbuild_id, 0,
 651                                                            &realname);
 652                         if (fd >= 0)
 653                                 close(fd); /* retaining reference by realname */
 654                         debuginfod_end(c);
 655                 }
 656         }
 657 #endif
 658
 659 out:
 660         free(debugfile);
 661         return realname;
 662 }
 663
 664 int build_id_cache__add_s(const char *sbuild_id, const char *name,
 665                           struct nsinfo *nsi, bool is_kallsyms, bool is_vdso)
 666 {
 667         const size_t size = PATH_MAX;
 668         char *realname = NULL, *filename = NULL, *dir_name = NULL,
 669              *linkname = zalloc(size), *tmp;
 670         char *debugfile = NULL;
 671         int err = -1;
 672
 673         if (!is_kallsyms) {
 674                 if (!is_vdso)
 675                         realname = nsinfo__realpath(name, nsi);
 676                 else
 677                         realname = realpath(name, NULL);
 678                 if (!realname)
 679                         goto out_free;
 680         }
 681
 682         dir_name = build_id_cache__cachedir(sbuild_id, name, nsi, is_kallsyms,
 683                                             is_vdso);
 684         if (!dir_name)
 685                 goto out_free;
 686
 687         /* Remove old style build-id cache */
 688         if (is_regular_file(dir_name))
 689                 if (unlink(dir_name))
 690                         goto out_free;
 691
 692         if (mkdir_p(dir_name, 0755))
 693                 goto out_free;
 694
 695         /* Save the allocated buildid dirname */
 696         if (asprintf(&filename, "%s/%s", dir_name,
 697                      build_id_cache__basename(is_kallsyms, is_vdso,
 698                      false)) < 0) {
 699                 filename = NULL;
 700                 goto out_free;
 701         }
 702
 703         if (access(filename, F_OK)) {
 704                 if (is_kallsyms) {
 705                         if (copyfile("/proc/kallsyms", filename))
 706                                 goto out_free;
 707                 } else if (nsi && nsi->need_setns) {
 708                         if (copyfile_ns(name, filename, nsi))
 709                                 goto out_free;
 710                 } else if (link(realname, filename) && errno != EEXIST &&
 711                                 copyfile(name, filename))
 712                         goto out_free;
 713         }
 714
 715         /* Some binaries are stripped, but have .debug files with their symbol
 716          * table.  Check to see if we can locate one of those, since the elf
 717          * file itself may not be very useful to users of our tools without a
 718          * symtab.
 719          */
 720         if (!is_kallsyms && !is_vdso &&
 721             strncmp(".ko", name + strlen(name) - 3, 3)) {
 722                 debugfile = build_id_cache__find_debug(sbuild_id, nsi);
 723                 if (debugfile) {
 724                         zfree(&filename);
 725                         if (asprintf(&filename, "%s/%s", dir_name,
 726                             build_id_cache__basename(false, false, true)) < 0) {
 727                                 filename = NULL;
 728                                 goto out_free;
 729                         }
 730                         if (access(filename, F_OK)) {
 731                                 if (nsi && nsi->need_setns) {
 732                                         if (copyfile_ns(debugfile, filename,
 733                                                         nsi))
 734                                                 goto out_free;
 735                                 } else if (link(debugfile, filename) &&
 736                                                 errno != EEXIST &&
 737                                                 copyfile(debugfile, filename))
 738                                         goto out_free;
 739                         }
 740                 }
 741         }
 742
 743         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 744                 goto out_free;
 745         tmp = strrchr(linkname, '/');
 746         *tmp = '\0';
 747
 748         if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
 749                 goto out_free;
 750
 751         *tmp = '/';
 752         tmp = dir_name + strlen(buildid_dir) - 5;
 753         memcpy(tmp, "../..", 5);
 754
 755         if (symlink(tmp, linkname) == 0)
 756                 err = 0;
 757
 758         /* Update SDT cache : error is just warned */
 759         if (realname &&
 760             build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) < 0)
 761                 pr_debug4("Failed to update/scan SDT cache for %s\n", realname);
 762
 763 out_free:
 764         if (!is_kallsyms)
 765                 free(realname);
 766         free(filename);
 767         free(debugfile);
 768         free(dir_name);
 769         free(linkname);
 770         return err;
 771 }
 772
 773 static int build_id_cache__add_b(const struct build_id *bid,
 774                                  const char *name, struct nsinfo *nsi,
 775                                  bool is_kallsyms, bool is_vdso)
 776 {
 777         char sbuild_id[SBUILD_ID_SIZE];
 778
 779         build_id__sprintf(bid, sbuild_id);
 780
 781         return build_id_cache__add_s(sbuild_id, name, nsi, is_kallsyms,
 782                                      is_vdso);
 783 }
 784
 785 bool build_id_cache__cached(const char *sbuild_id)
 786 {
 787         bool ret = false;
 788         char *filename = build_id_cache__linkname(sbuild_id, NULL, 0);
 789
 790         if (filename && !access(filename, F_OK))
 791                 ret = true;
 792         free(filename);
 793
 794         return ret;
 795 }
 796
 797 int build_id_cache__remove_s(const char *sbuild_id)
 798 {
 799         const size_t size = PATH_MAX;
 800         char *filename = zalloc(size),
 801              *linkname = zalloc(size), *tmp;
 802         int err = -1;
 803
 804         if (filename == NULL || linkname == NULL)
 805                 goto out_free;
 806
 807         if (!build_id_cache__linkname(sbuild_id, linkname, size))
 808                 goto out_free;
 809
 810         if (access(linkname, F_OK))
 811                 goto out_free;
 812
 813         if (readlink(linkname, filename, size - 1) < 0)
 814                 goto out_free;
 815
 816         if (unlink(linkname))
 817                 goto out_free;
 818
 819         /*
 820          * Since the link is relative, we must make it absolute:
 821          */
 822         tmp = strrchr(linkname, '/') + 1;
 823         snprintf(tmp, size - (tmp - linkname), "%s", filename);
 824
 825         if (rm_rf(linkname))
 826                 goto out_free;
 827
 828         err = 0;
 829 out_free:
 830         free(filename);
 831         free(linkname);
 832         return err;
 833 }
 834
 835 static int dso__cache_build_id(struct dso *dso, struct machine *machine)
 836 {
 837         bool is_kallsyms = dso__is_kallsyms(dso);
 838         bool is_vdso = dso__is_vdso(dso);
 839         const char *name = dso->long_name;
 840
 841         if (dso__is_kcore(dso)) {
 842                 is_kallsyms = true;
 843                 name = machine->mmap_name;
 844         }
 845         return build_id_cache__add_b(&dso->bid, name, dso->nsinfo,
 846                                      is_kallsyms, is_vdso);
 847 }
 848
 849 static int __dsos__cache_build_ids(struct list_head *head,
 850                                    struct machine *machine)
 851 {
 852         struct dso *pos;
 853         int err = 0;
 854
 855         dsos__for_each_with_build_id(pos, head)
 856                 if (dso__cache_build_id(pos, machine))
 857                         err = -1;
 858
 859         return err;
 860 }
 861
 862 static int machine__cache_build_ids(struct machine *machine)
 863 {
 864         return __dsos__cache_build_ids(&machine->dsos.head, machine);
 865 }
 866
 867 int perf_session__cache_build_ids(struct perf_session *session)
 868 {
 869         struct rb_node *nd;
 870         int ret;
 871
 872         if (no_buildid_cache)
 873                 return 0;
 874
 875         if (mkdir(buildid_dir, 0755) != 0 && errno != EEXIST)
 876                 return -1;
 877
 878         ret = machine__cache_build_ids(&session->machines.host);
 879
 880         for (nd = rb_first_cached(&session->machines.guests); nd;
 881              nd = rb_next(nd)) {
 882                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 883                 ret |= machine__cache_build_ids(pos);
 884         }
 885         return ret ? -1 : 0;
 886 }
 887
 888 static bool machine__read_build_ids(struct machine *machine, bool with_hits)
 889 {
 890         return __dsos__read_build_ids(&machine->dsos.head, with_hits);
 891 }
 892
 893 bool perf_session__read_build_ids(struct perf_session *session, bool with_hits)
 894 {
 895         struct rb_node *nd;
 896         bool ret = machine__read_build_ids(&session->machines.host, with_hits);
 897
 898         for (nd = rb_first_cached(&session->machines.guests); nd;
 899              nd = rb_next(nd)) {
 900                 struct machine *pos = rb_entry(nd, struct machine, rb_node);
 901                 ret |= machine__read_build_ids(pos, with_hits);
 902         }
 903
 904         return ret;
 905 }
 906
 907 void build_id__init(struct build_id *bid, const u8 *data, size_t size)
 908 {
 909         WARN_ON(size > BUILD_ID_SIZE);
 910         memcpy(bid->data, data, size);
 911         bid->size = size;
 912 }