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