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 <linux/string.h>
 41#include <asm/bug.h>
 42
 43static bool no_buildid_cache;
 44
 45static int mark_dso_hit_callback(struct callchain_cursor_node *node, void *data __maybe_unused)
 46{
 47	struct map *map = node->ms.map;
 48
 49	if (map)
 50		dso__set_hit(map__dso(map));
 51
 52	return 0;
 53}
 54
 55int build_id__mark_dso_hit(const struct perf_tool *tool __maybe_unused,
 56			   union perf_event *event,
 57			   struct perf_sample *sample,
 58			   struct evsel *evsel,
 59			   struct machine *machine)
 60{
 61	struct addr_location al;
 62	struct thread *thread = machine__findnew_thread(machine, sample->pid,
 63							sample->tid);
 64
 65	if (thread == NULL) {
 66		pr_err("problem processing %d event, skipping it.\n",
 67			event->header.type);
 68		return -1;
 69	}
 70
 71	addr_location__init(&al);
 72	if (thread__find_map(thread, sample->cpumode, sample->ip, &al))
 73		dso__set_hit(map__dso(al.map));
 74
 75	addr_location__exit(&al);
 76
 77	sample__for_each_callchain_node(thread, evsel, sample, PERF_MAX_STACK_DEPTH,
 78					/*symbols=*/false, mark_dso_hit_callback, /*data=*/NULL);
 79
 80
 81	thread__put(thread);
 82	return 0;
 83}
 84
 85int build_id__snprintf(const struct build_id *build_id, char *bf, size_t bf_size)
 86{
 87	size_t offs = 0;
 88
 89	if (build_id->size == 0) {
 90		/* Ensure bf is always \0 terminated. */
 91		if (bf_size > 0)
 92			bf[0] = '\0';
 93		return 0;
 94	}
 95
 96	for (size_t i = 0; i < build_id->size && offs < bf_size; ++i)
 97		offs += snprintf(bf + offs, bf_size - offs, "%02x", build_id->data[i]);
 98
 99	return offs;
100}
101
102int sysfs__snprintf_build_id(const char *root_dir, char *sbuild_id, size_t sbuild_id_size)
103{
104	char notes[PATH_MAX];
105	struct build_id bid = { .size = 0, };
106	int ret;
107
108	if (!root_dir)
109		root_dir = "";
110
111	scnprintf(notes, sizeof(notes), "%s/sys/kernel/notes", root_dir);
112
113	ret = sysfs__read_build_id(notes, &bid);
114	if (ret < 0)
115		return ret;
116
117	return build_id__snprintf(&bid, sbuild_id, sbuild_id_size);
118}
119
120int filename__snprintf_build_id(const char *pathname, char *sbuild_id, size_t sbuild_id_size)
121{
122	struct build_id bid = { .size = 0, };
123	int ret;
124
125	ret = filename__read_build_id(pathname, &bid);
126	if (ret < 0)
127		return ret;
128
129	return build_id__snprintf(&bid, sbuild_id, sbuild_id_size);
130}
131
132/* asnprintf consolidates asprintf and snprintf */
133static int asnprintf(char **strp, size_t size, const char *fmt, ...)
134{
135	va_list ap;
136	int ret;
137
138	if (!strp)
139		return -EINVAL;
140
141	va_start(ap, fmt);
142	if (*strp)
143		ret = vsnprintf(*strp, size, fmt, ap);
144	else
145		ret = vasprintf(strp, fmt, ap);
146	va_end(ap);
147
148	return ret;
149}
150
151char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
152				    size_t size)
153{
154	bool retry_old = true;
155
156	snprintf(bf, size, "%s/%s/%s/kallsyms",
157		 buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
158retry:
159	if (!access(bf, F_OK))
160		return bf;
161	if (retry_old) {
162		/* Try old style kallsyms cache */
163		snprintf(bf, size, "%s/%s/%s",
164			 buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
165		retry_old = false;
166		goto retry;
167	}
168
169	return NULL;
170}
171
172char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size)
173{
174	char *tmp = bf;
175	int ret = asnprintf(&bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
176			    sbuild_id, sbuild_id + 2);
177	if (ret < 0 || (tmp && size < (unsigned int)ret))
178		return NULL;
179	return bf;
180}
181
182/* The caller is responsible to free the returned buffer. */
183char *build_id_cache__origname(const char *sbuild_id)
184{
185	char *linkname;
186	char buf[PATH_MAX];
187	char *ret = NULL, *p;
188	size_t offs = 5;	/* == strlen("../..") */
189	ssize_t len;
190
191	linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
192	if (!linkname)
193		return NULL;
194
195	len = readlink(linkname, buf, sizeof(buf) - 1);
196	if (len <= 0)
197		goto out;
198	buf[len] = '\0';
199
200	/* The link should be "../..<origpath>/<sbuild_id>" */
201	p = strrchr(buf, '/');	/* Cut off the "/<sbuild_id>" */
202	if (p && (p > buf + offs)) {
203		*p = '\0';
204		if (buf[offs + 1] == '[')
205			offs++;	/*
206				 * This is a DSO name, like [kernel.kallsyms].
207				 * Skip the first '/', since this is not the
208				 * cache of a regular file.
209				 */
210		ret = strdup(buf + offs);	/* Skip "../..[/]" */
211	}
212out:
213	free(linkname);
214	return ret;
215}
216
217/* Check if the given build_id cache is valid on current running system */
218static bool build_id_cache__valid_id(char *sbuild_id)
219{
220	char real_sbuild_id[SBUILD_ID_SIZE] = "";
221	char *pathname;
222	int ret = 0;
223	bool result = false;
224
225	pathname = build_id_cache__origname(sbuild_id);
226	if (!pathname)
227		return false;
228
229	if (!strcmp(pathname, DSO__NAME_KALLSYMS))
230		ret = sysfs__snprintf_build_id("/", real_sbuild_id, sizeof(real_sbuild_id));
231	else if (pathname[0] == '/')
232		ret = filename__snprintf_build_id(pathname, real_sbuild_id, sizeof(real_sbuild_id));
233	else
234		ret = -EINVAL;	/* Should we support other special DSO cache? */
235	if (ret >= 0)
236		result = (strcmp(sbuild_id, real_sbuild_id) == 0);
237	free(pathname);
238
239	return result;
240}
241
242static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso,
243					    bool is_debug)
244{
245	return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : (is_debug ?
246	    "debug" : "elf"));
247}
248
249char *__dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
250			       bool is_debug, bool is_kallsyms)
251{
252	bool is_vdso = dso__is_vdso((struct dso *)dso);
253	char sbuild_id[SBUILD_ID_SIZE];
254	char *linkname;
255	bool alloc = (bf == NULL);
256	int ret;
257
258	if (!dso__has_build_id(dso))
259		return NULL;
260
261	build_id__snprintf(dso__bid(dso), sbuild_id, sizeof(sbuild_id));
262	linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
263	if (!linkname)
264		return NULL;
265
266	/* Check if old style build_id cache */
267	if (is_regular_file(linkname))
268		ret = asnprintf(&bf, size, "%s", linkname);
269	else
270		ret = asnprintf(&bf, size, "%s/%s", linkname,
271			 build_id_cache__basename(is_kallsyms, is_vdso,
272						  is_debug));
273	if (ret < 0 || (!alloc && size < (unsigned int)ret))
274		bf = NULL;
275	free(linkname);
276
277	return bf;
278}
279
280char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
281			     bool is_debug)
282{
283	bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
284
285	return __dso__build_id_filename(dso, bf, size, is_debug, is_kallsyms);
286}
287
288static int write_buildid(const char *name, size_t name_len, struct build_id *bid,
289			 pid_t pid, u16 misc, struct feat_fd *fd)
290{
291	int err;
292	struct perf_record_header_build_id b;
293	size_t len;
294
295	len = name_len + 1;
296	len = PERF_ALIGN(len, sizeof(u64));
297
298	memset(&b, 0, sizeof(b));
299	memcpy(&b.data, bid->data, bid->size);
300	b.size = (u8) bid->size;
301	misc |= PERF_RECORD_MISC_BUILD_ID_SIZE;
302	b.pid = pid;
303	b.header.misc = misc;
304	b.header.size = sizeof(b) + len;
305
306	err = do_write(fd, &b, sizeof(b));
307	if (err < 0)
308		return err;
309
310	return write_padded(fd, name, name_len + 1, len);
311}
312
313struct machine__write_buildid_table_cb_args {
314	struct machine *machine;
315	struct feat_fd *fd;
316	u16 kmisc, umisc;
317};
318
319static int machine__write_buildid_table_cb(struct dso *dso, void *data)
320{
321	struct machine__write_buildid_table_cb_args *args = data;
322	const char *name;
323	size_t name_len;
324	bool in_kernel = false;
325
326	if (!dso__has_build_id(dso))
327		return 0;
328
329	if (!dso__hit(dso) && !dso__is_vdso(dso))
330		return 0;
331
332	if (dso__is_vdso(dso)) {
333		name = dso__short_name(dso);
334		name_len = dso__short_name_len(dso);
335	} else if (dso__is_kcore(dso)) {
336		name = args->machine->mmap_name;
337		name_len = strlen(name);
338	} else {
339		name = dso__long_name(dso);
340		name_len = dso__long_name_len(dso);
341	}
342
343	in_kernel = dso__kernel(dso) || is_kernel_module(name, PERF_RECORD_MISC_CPUMODE_UNKNOWN);
344	return write_buildid(name, name_len, &dso__id(dso)->build_id, args->machine->pid,
345			     in_kernel ? args->kmisc : args->umisc, args->fd);
346}
347
348static int machine__write_buildid_table(struct machine *machine, struct feat_fd *fd)
349{
350	struct machine__write_buildid_table_cb_args args = {
351		.machine = machine,
352		.fd = fd,
353		.kmisc = PERF_RECORD_MISC_KERNEL,
354		.umisc = PERF_RECORD_MISC_USER,
355	};
356
357	if (!machine__is_host(machine)) {
358		args.kmisc = PERF_RECORD_MISC_GUEST_KERNEL;
359		args.umisc = PERF_RECORD_MISC_GUEST_USER;
360	}
361
362	return dsos__for_each_dso(&machine->dsos, machine__write_buildid_table_cb, &args);
363}
364
365int perf_session__write_buildid_table(struct perf_session *session,
366				      struct feat_fd *fd)
367{
368	struct rb_node *nd;
369	int err = machine__write_buildid_table(&session->machines.host, fd);
370
371	if (err)
372		return err;
373
374	for (nd = rb_first_cached(&session->machines.guests); nd;
375	     nd = rb_next(nd)) {
376		struct machine *pos = rb_entry(nd, struct machine, rb_node);
377		err = machine__write_buildid_table(pos, fd);
378		if (err)
379			break;
380	}
381	return err;
382}
383
384void disable_buildid_cache(void)
385{
386	no_buildid_cache = true;
387}
388
389static bool lsdir_bid_head_filter(const char *name __maybe_unused,
390				  struct dirent *d)
391{
392	return (strlen(d->d_name) == 2) &&
393		isxdigit(d->d_name[0]) && isxdigit(d->d_name[1]);
394}
395
396static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
397				  struct dirent *d)
398{
399	int i = 0;
400	while (isxdigit(d->d_name[i]) && i < SBUILD_ID_SIZE - 3)
401		i++;
402	return (i >= SBUILD_ID_MIN_SIZE - 3) && (i <= SBUILD_ID_SIZE - 3) &&
403		(d->d_name[i] == '\0');
404}
405
406struct strlist *build_id_cache__list_all(bool validonly)
407{
408	struct strlist *toplist, *linklist = NULL, *bidlist;
409	struct str_node *nd, *nd2;
410	char *topdir, *linkdir = NULL;
411	char sbuild_id[SBUILD_ID_SIZE];
412
413	/* for filename__ functions */
414	if (validonly)
415		symbol__init(NULL);
416
417	/* Open the top-level directory */
418	if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
419		return NULL;
420
421	bidlist = strlist__new(NULL, NULL);
422	if (!bidlist)
423		goto out;
424
425	toplist = lsdir(topdir, lsdir_bid_head_filter);
426	if (!toplist) {
427		pr_debug("Error in lsdir(%s): %d\n", topdir, errno);
428		/* If there is no buildid cache, return an empty list */
429		if (errno == ENOENT)
430			goto out;
431		goto err_out;
432	}
433
434	strlist__for_each_entry(nd, toplist) {
435		if (asprintf(&linkdir, "%s/%s", topdir, nd->s) < 0)
436			goto err_out;
437		/* Open the lower-level directory */
438		linklist = lsdir(linkdir, lsdir_bid_tail_filter);
439		if (!linklist) {
440			pr_debug("Error in lsdir(%s): %d\n", linkdir, errno);
441			goto err_out;
442		}
443		strlist__for_each_entry(nd2, linklist) {
444			if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
445				     nd->s, nd2->s) > SBUILD_ID_SIZE - 1)
446				goto err_out;
447			if (validonly && !build_id_cache__valid_id(sbuild_id))
448				continue;
449			if (strlist__add(bidlist, sbuild_id) < 0)
450				goto err_out;
451		}
452		strlist__delete(linklist);
453		zfree(&linkdir);
454	}
455
456out_free:
457	strlist__delete(toplist);
458out:
459	free(topdir);
460
461	return bidlist;
462
463err_out:
464	strlist__delete(linklist);
465	zfree(&linkdir);
466	strlist__delete(bidlist);
467	bidlist = NULL;
468	goto out_free;
469}
470
471static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)
472{
473	size_t i;
474
475	for (i = 0; i < len; i++) {
476		if (!isxdigit(maybe_sbuild_id[i]))
477			return false;
478	}
479	return true;
480}
481
482/* Return the valid complete build-id */
483char *build_id_cache__complement(const char *incomplete_sbuild_id)
484{
485	struct strlist *bidlist;
486	struct str_node *nd, *cand = NULL;
487	char *sbuild_id = NULL;
488	size_t len = strlen(incomplete_sbuild_id);
489
490	if (len >= SBUILD_ID_SIZE ||
491	    !str_is_build_id(incomplete_sbuild_id, len))
492		return NULL;
493
494	bidlist = build_id_cache__list_all(true);
495	if (!bidlist)
496		return NULL;
497
498	strlist__for_each_entry(nd, bidlist) {
499		if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)
500			continue;
501		if (cand) {	/* Error: There are more than 2 candidates. */
502			cand = NULL;
503			break;
504		}
505		cand = nd;
506	}
507	if (cand)
508		sbuild_id = strdup(cand->s);
509	strlist__delete(bidlist);
510
511	return sbuild_id;
512}
513
514char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
515			       struct nsinfo *nsi, bool is_kallsyms,
516			       bool is_vdso)
517{
518	char *realname = NULL, *filename;
519	bool slash = is_kallsyms || is_vdso;
520
521	if (!slash)
522		realname = nsinfo__realpath(name, nsi);
523
524	if (asprintf(&filename, "%s%s%s%s%s", buildid_dir, slash ? "/" : "",
525		     is_vdso ? DSO__NAME_VDSO : (realname ? realname : name),
526		     sbuild_id ? "/" : "", sbuild_id ?: "") < 0)
527		filename = NULL;
528
529	free(realname);
530	return filename;
531}
532
533int build_id_cache__list_build_ids(const char *pathname, struct nsinfo *nsi,
534				   struct strlist **result)
535{
536	char *dir_name;
537	int ret = 0;
538
539	dir_name = build_id_cache__cachedir(NULL, pathname, nsi, false, false);
540	if (!dir_name)
541		return -ENOMEM;
542
543	*result = lsdir(dir_name, lsdir_no_dot_filter);
544	if (!*result)
545		ret = -errno;
546	free(dir_name);
547
548	return ret;
549}
550
551#if defined(HAVE_LIBELF_SUPPORT) && defined(HAVE_GELF_GETNOTE_SUPPORT)
552static int build_id_cache__add_sdt_cache(const char *sbuild_id,
553					  const char *realname,
554					  struct nsinfo *nsi)
555{
556	struct probe_cache *cache;
557	int ret;
558	struct nscookie nsc;
559
560	cache = probe_cache__new(sbuild_id, nsi);
561	if (!cache)
562		return -1;
563
564	nsinfo__mountns_enter(nsi, &nsc);
565	ret = probe_cache__scan_sdt(cache, realname);
566	nsinfo__mountns_exit(&nsc);
567	if (ret >= 0) {
568		pr_debug4("Found %d SDTs in %s\n", ret, realname);
569		if (probe_cache__commit(cache) < 0)
570			ret = -1;
571	}
572	probe_cache__delete(cache);
573	return ret;
574}
575#else
576#define build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) (0)
577#endif
578
579static char *build_id_cache__find_debug(const char *sbuild_id,
580					struct nsinfo *nsi,
581					const char *root_dir)
582{
583	const char *dirname = "/usr/lib/debug/.build-id/";
584	char *realname = NULL;
585	char dirbuf[PATH_MAX];
586	char *debugfile;
587	struct nscookie nsc;
588	size_t len = 0;
589
590	debugfile = calloc(1, PATH_MAX);
591	if (!debugfile)
592		goto out;
593
594	if (root_dir) {
595		path__join(dirbuf, PATH_MAX, root_dir, dirname);
596		dirname = dirbuf;
597	}
598
599	len = __symbol__join_symfs(debugfile, PATH_MAX, dirname);
600	snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,
601		 sbuild_id + 2);
602
603	nsinfo__mountns_enter(nsi, &nsc);
604	realname = realpath(debugfile, NULL);
605	if (realname && access(realname, R_OK))
606		zfree(&realname);
607	nsinfo__mountns_exit(&nsc);
608
609#ifdef HAVE_DEBUGINFOD_SUPPORT
610	if (realname == NULL) {
611		debuginfod_client* c;
612
613		pr_debug("Downloading debug info with build id %s\n", sbuild_id);
614
615		c = debuginfod_begin();
616		if (c != NULL) {
617			int fd = debuginfod_find_debuginfo(c,
618					(const unsigned char*)sbuild_id, 0,
619					&realname);
620			if (fd >= 0)
621				close(fd); /* retaining reference by realname */
622			debuginfod_end(c);
623		}
624	}
625#endif
626
627out:
628	free(debugfile);
629	return realname;
630}
631
632int
633build_id_cache__add(const char *sbuild_id, const char *name, const char *realname,
634		    struct nsinfo *nsi, bool is_kallsyms, bool is_vdso,
635		    const char *proper_name, const char *root_dir)
636{
637	const size_t size = PATH_MAX;
638	char *filename = NULL, *dir_name = NULL, *linkname = zalloc(size), *tmp;
639	char *debugfile = NULL;
640	int err = -1;
641
642	if (!proper_name)
643		proper_name = name;
644
645	dir_name = build_id_cache__cachedir(sbuild_id, proper_name, nsi, is_kallsyms,
646					    is_vdso);
647	if (!dir_name)
648		goto out_free;
649
650	/* Remove old style build-id cache */
651	if (is_regular_file(dir_name))
652		if (unlink(dir_name))
653			goto out_free;
654
655	if (mkdir_p(dir_name, 0755))
656		goto out_free;
657
658	/* Save the allocated buildid dirname */
659	if (asprintf(&filename, "%s/%s", dir_name,
660		     build_id_cache__basename(is_kallsyms, is_vdso,
661		     false)) < 0) {
662		filename = NULL;
663		goto out_free;
664	}
665
666	if (access(filename, F_OK)) {
667		if (is_kallsyms) {
668			if (copyfile("/proc/kallsyms", filename))
669				goto out_free;
670		} else if (nsi && nsinfo__need_setns(nsi)) {
671			if (copyfile_ns(name, filename, nsi))
672				goto out_free;
673		} else if (link(realname, filename) && errno != EEXIST) {
674			struct stat f_stat;
675
676			if (!(stat(name, &f_stat) < 0) &&
677					copyfile_mode(name, filename, f_stat.st_mode))
678				goto out_free;
679		}
680	}
681
682	/* Some binaries are stripped, but have .debug files with their symbol
683	 * table.  Check to see if we can locate one of those, since the elf
684	 * file itself may not be very useful to users of our tools without a
685	 * symtab.
686	 */
687	if (!is_kallsyms && !is_vdso &&
688	    strncmp(".ko", name + strlen(name) - 3, 3)) {
689		debugfile = build_id_cache__find_debug(sbuild_id, nsi, root_dir);
690		if (debugfile) {
691			zfree(&filename);
692			if (asprintf(&filename, "%s/%s", dir_name,
693			    build_id_cache__basename(false, false, true)) < 0) {
694				filename = NULL;
695				goto out_free;
696			}
697			if (access(filename, F_OK)) {
698				if (nsi && nsinfo__need_setns(nsi)) {
699					if (copyfile_ns(debugfile, filename,
700							nsi))
701						goto out_free;
702				} else if (link(debugfile, filename) &&
703						errno != EEXIST &&
704						copyfile(debugfile, filename))
705					goto out_free;
706			}
707		}
708	}
709
710	if (!build_id_cache__linkname(sbuild_id, linkname, size))
711		goto out_free;
712	tmp = strrchr(linkname, '/');
713	*tmp = '\0';
714
715	if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
716		goto out_free;
717
718	*tmp = '/';
719	tmp = dir_name + strlen(buildid_dir) - 5;
720	memcpy(tmp, "../..", 5);
721
722	if (symlink(tmp, linkname) == 0) {
723		err = 0;
724	} else if (errno == EEXIST) {
725		char path[PATH_MAX];
726		ssize_t len;
727
728		len = readlink(linkname, path, sizeof(path) - 1);
729		if (len <= 0) {
730			pr_err("Can't read link: %s\n", linkname);
731			goto out_free;
732		}
733		path[len] = '\0';
734
735		if (strcmp(tmp, path)) {
736			pr_debug("build <%s> already linked to %s\n",
737				 sbuild_id, linkname);
738		}
739		err = 0;
740	}
741
742	/* Update SDT cache : error is just warned */
743	if (realname &&
744	    build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) < 0)
745		pr_debug4("Failed to update/scan SDT cache for %s\n", realname);
746
747out_free:
748	free(filename);
749	free(debugfile);
750	free(dir_name);
751	free(linkname);
752	return err;
753}
754
755int __build_id_cache__add_s(const char *sbuild_id, const char *name,
756			    struct nsinfo *nsi, bool is_kallsyms, bool is_vdso,
757			    const char *proper_name, const char *root_dir)
758{
759	char *realname = NULL;
760	int err = -1;
761
762	if (!is_kallsyms) {
763		if (!is_vdso)
764			realname = nsinfo__realpath(name, nsi);
765		else
766			realname = realpath(name, NULL);
767		if (!realname)
768			goto out_free;
769	}
770
771	err = build_id_cache__add(sbuild_id, name, realname, nsi,
772				  is_kallsyms, is_vdso, proper_name, root_dir);
773out_free:
774	if (!is_kallsyms)
775		free(realname);
776	return err;
777}
778
779static int build_id_cache__add_b(const struct build_id *bid,
780				 const char *name, struct nsinfo *nsi,
781				 bool is_kallsyms, bool is_vdso,
782				 const char *proper_name,
783				 const char *root_dir)
784{
785	char sbuild_id[SBUILD_ID_SIZE];
786
787	build_id__snprintf(bid, sbuild_id, sizeof(sbuild_id));
788
789	return __build_id_cache__add_s(sbuild_id, name, nsi, is_kallsyms,
790				       is_vdso, proper_name, root_dir);
791}
792
793bool build_id_cache__cached(const char *sbuild_id)
794{
795	bool ret = false;
796	char *filename = build_id_cache__linkname(sbuild_id, NULL, 0);
797
798	if (filename && !access(filename, F_OK))
799		ret = true;
800	free(filename);
801
802	return ret;
803}
804
805int build_id_cache__remove_s(const char *sbuild_id)
806{
807	const size_t size = PATH_MAX;
808	char *filename = zalloc(size),
809	     *linkname = zalloc(size), *tmp;
810	int err = -1;
811
812	if (filename == NULL || linkname == NULL)
813		goto out_free;
814
815	if (!build_id_cache__linkname(sbuild_id, linkname, size))
816		goto out_free;
817
818	if (access(linkname, F_OK))
819		goto out_free;
820
821	if (readlink(linkname, filename, size - 1) < 0)
822		goto out_free;
823
824	if (unlink(linkname))
825		goto out_free;
826
827	/*
828	 * Since the link is relative, we must make it absolute:
829	 */
830	tmp = strrchr(linkname, '/') + 1;
831	snprintf(tmp, size - (tmp - linkname), "%s", filename);
832
833	if (rm_rf(linkname))
834		goto out_free;
835
836	err = 0;
837out_free:
838	free(filename);
839	free(linkname);
840	return err;
841}
842
843static int filename__read_build_id_ns(const char *filename,
844				      struct build_id *bid,
845				      struct nsinfo *nsi)
846{
847	struct nscookie nsc;
848	int ret;
849
850	nsinfo__mountns_enter(nsi, &nsc);
851	ret = filename__read_build_id(filename, bid);
852	nsinfo__mountns_exit(&nsc);
853
854	return ret;
855}
856
857static bool dso__build_id_mismatch(struct dso *dso, const char *name)
858{
859	struct build_id bid = { .size = 0, };
860	bool ret = false;
861
862	mutex_lock(dso__lock(dso));
863	if (filename__read_build_id_ns(name, &bid, dso__nsinfo(dso)) >= 0)
864		ret = !dso__build_id_equal(dso, &bid);
865
866	mutex_unlock(dso__lock(dso));
867
868	return ret;
869}
870
871static int dso__cache_build_id(struct dso *dso, struct machine *machine,
872			       void *priv __maybe_unused)
873{
874	bool is_kallsyms = dso__is_kallsyms(dso);
875	bool is_vdso = dso__is_vdso(dso);
876	const char *name = dso__long_name(dso);
877	const char *proper_name = NULL;
878	const char *root_dir = NULL;
879	char *allocated_name = NULL;
880	int ret = 0;
881
882	if (!dso__has_build_id(dso) || !dso__hit(dso))
883		return 0;
884
885	if (dso__is_kcore(dso)) {
886		is_kallsyms = true;
887		name = machine->mmap_name;
888	}
889
890	if (!machine__is_host(machine)) {
891		if (*machine->root_dir) {
892			root_dir = machine->root_dir;
893			ret = asprintf(&allocated_name, "%s/%s", root_dir, name);
894			if (ret < 0)
895				return ret;
896			proper_name = name;
897			name = allocated_name;
898		} else if (is_kallsyms) {
899			/* Cannot get guest kallsyms */
900			return 0;
901		}
902	}
903
904	if (!is_kallsyms && dso__build_id_mismatch(dso, name))
905		goto out_free;
906
907	mutex_lock(dso__lock(dso));
908	ret = build_id_cache__add_b(dso__bid(dso), name, dso__nsinfo(dso),
909				    is_kallsyms, is_vdso, proper_name, root_dir);
910	mutex_unlock(dso__lock(dso));
911out_free:
912	free(allocated_name);
913	return ret;
914}
915
916static int
917machines__for_each_dso(struct machines *machines, machine__dso_t fn, void *priv)
918{
919	int ret = machine__for_each_dso(&machines->host, fn, priv);
920	struct rb_node *nd;
921
922	for (nd = rb_first_cached(&machines->guests); nd;
923	     nd = rb_next(nd)) {
924		struct machine *pos = rb_entry(nd, struct machine, rb_node);
925
926		ret |= machine__for_each_dso(pos, fn, priv);
927	}
928	return ret ? -1 : 0;
929}
930
931int __perf_session__cache_build_ids(struct perf_session *session,
932				    machine__dso_t fn, void *priv)
933{
934	if (no_buildid_cache)
935		return 0;
936
937	if (mkdir(buildid_dir, 0755) != 0 && errno != EEXIST)
938		return -1;
939
940	return machines__for_each_dso(&session->machines, fn, priv) ?  -1 : 0;
941}
942
943int perf_session__cache_build_ids(struct perf_session *session)
944{
945	return __perf_session__cache_build_ids(session, dso__cache_build_id, NULL);
946}
947
948static bool machine__read_build_ids(struct machine *machine, bool with_hits)
949{
950	return dsos__read_build_ids(&machine->dsos, with_hits);
951}
952
953bool perf_session__read_build_ids(struct perf_session *session, bool with_hits)
954{
955	struct rb_node *nd;
956	bool ret = machine__read_build_ids(&session->machines.host, with_hits);
957
958	for (nd = rb_first_cached(&session->machines.guests); nd;
959	     nd = rb_next(nd)) {
960		struct machine *pos = rb_entry(nd, struct machine, rb_node);
961		ret |= machine__read_build_ids(pos, with_hits);
962	}
963
964	return ret;
965}
966
967void build_id__init(struct build_id *bid, const u8 *data, size_t size)
968{
969	if (size > BUILD_ID_SIZE) {
970		pr_debug("Truncating build_id size from %zd\n", size);
971		size = BUILD_ID_SIZE;
972	}
973	memcpy(bid->data, data, size);
974	bid->size = size;
975}
976
977bool build_id__is_defined(const struct build_id *bid)
978{
979	return bid && bid->size ? !!memchr_inv(bid->data, 0, bid->size) : false;
980}