1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * build-id.c
   4 *
   5 * build-id support
   6 *
   7 * Copyright (C) 2009, 2010 Red Hat Inc.
   8 * Copyright (C) 2009, 2010 Arnaldo Carvalho de Melo <acme@redhat.com>
   9 */
  10#include "util.h" // lsdir(), mkdir_p(), rm_rf()
  11#include <dirent.h>
  12#include <errno.h>
  13#include <stdio.h>
  14#include <sys/stat.h>
  15#include <sys/types.h>
  16#include "util/copyfile.h"
  17#include "dso.h"
  18#include "build-id.h"
  19#include "event.h"
  20#include "namespaces.h"
  21#include "map.h"
  22#include "symbol.h"
  23#include "thread.h"
  24#include <linux/kernel.h>
  25#include "debug.h"
  26#include "session.h"
  27#include "tool.h"
  28#include "header.h"
  29#include "vdso.h"
  30#include "path.h"
  31#include "probe-file.h"
  32#include "strlist.h"
  33
  34#ifdef HAVE_DEBUGINFOD_SUPPORT
  35#include <elfutils/debuginfod.h>
  36#endif
  37
  38#include <linux/ctype.h>
  39#include <linux/zalloc.h>
  40#include <linux/string.h>
  41#include <asm/bug.h>
  42
  43static bool no_buildid_cache;
  44
  45int build_id__mark_dso_hit(struct perf_tool *tool __maybe_unused,
  46			   union perf_event *event,
  47			   struct perf_sample *sample,
  48			   struct evsel *evsel __maybe_unused,
  49			   struct machine *machine)
  50{
  51	struct addr_location al;
 
  52	struct thread *thread = machine__findnew_thread(machine, sample->pid,
  53							sample->tid);
  54
  55	if (thread == NULL) {
  56		pr_err("problem processing %d event, skipping it.\n",
  57			event->header.type);
  58		return -1;
  59	}
  60
  61	if (thread__find_map(thread, sample->cpumode, sample->ip, &al))
 
 
 
  62		al.map->dso->hit = 1;
  63
  64	thread__put(thread);
  65	return 0;
  66}
  67
  68static 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
  89struct 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
 100int 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
 117int 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
 135int 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 */
 148static 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
 166char *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);
 173retry:
 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
 187char *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. */
 198char *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	}
 227out:
 228	free(linkname);
 229	return ret;
 230}
 231
 232/* Check if the given build_id cache is valid on current running system */
 233static 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
 257static 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
 264char *__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
 295char *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
 303static 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
 328static 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
 372int 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
 391static 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
 401static int machine__hit_all_dsos(struct machine *machine)
 402{
 403	return __dsos__hit_all(&machine->dsos.head);
 404}
 405
 406int 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
 427void disable_buildid_cache(void)
 428{
 429	no_buildid_cache = true;
 430}
 431
 432static 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
 439static 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
 449struct 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
 499out_free:
 500	strlist__delete(toplist);
 501out:
 502	free(topdir);
 503
 504	return bidlist;
 505
 506err_out:
 507	strlist__delete(linklist);
 508	zfree(&linkdir);
 509	strlist__delete(bidlist);
 510	bidlist = NULL;
 511	goto out_free;
 512}
 513
 514static 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 */
 526char *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
 557char *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
 578int 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)
 597static 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
 624static 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
 672out:
 673	free(debugfile);
 674	return realname;
 675}
 676
 677int
 678build_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
 792out_free:
 793	free(filename);
 794	free(debugfile);
 795	free(dir_name);
 796	free(linkname);
 797	return err;
 798}
 799
 800int __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);
 818out_free:
 819	if (!is_kallsyms)
 820		free(realname);
 821	return err;
 822}
 823
 824static 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
 838bool 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
 850int 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;
 882out_free:
 883	free(filename);
 884	free(linkname);
 885	return err;
 886}
 887
 888static 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
 902static 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
 916static 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);
 956out_free:
 957	free(allocated_name);
 958	return ret;
 959}
 960
 961static int
 962machines__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
 976int __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
 988int 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
 993static 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
 998bool 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
1012void 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
1019bool build_id__is_defined(const struct build_id *bid)
1020{
1021	return bid && bid->size ? !!memchr_inv(bid->data, 0, bid->size) : false;
1022}