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	addr_location__init(&al);
62	if (thread__find_map(thread, sample->cpumode, sample->ip, &al))
63		map__dso(al.map)->hit = 1;
64
65	addr_location__exit(&al);
66	thread__put(thread);
67	return 0;
68}
69
70static int perf_event__exit_del_thread(struct perf_tool *tool __maybe_unused,
71				       union perf_event *event,
72				       struct perf_sample *sample
73				       __maybe_unused,
74				       struct machine *machine)
75{
76	struct thread *thread = machine__findnew_thread(machine,
77							event->fork.pid,
78							event->fork.tid);
79
80	dump_printf("(%d:%d):(%d:%d)\n", event->fork.pid, event->fork.tid,
81		    event->fork.ppid, event->fork.ptid);
82
83	if (thread) {
84		machine__remove_thread(machine, thread);
85		thread__put(thread);
86	}
87
88	return 0;
89}
90
91struct perf_tool build_id__mark_dso_hit_ops = {
92	.sample	= build_id__mark_dso_hit,
93	.mmap	= perf_event__process_mmap,
94	.mmap2	= perf_event__process_mmap2,
95	.fork	= perf_event__process_fork,
96	.exit	= perf_event__exit_del_thread,
97	.attr		 = perf_event__process_attr,
98	.build_id	 = perf_event__process_build_id,
99	.ordered_events	 = true,
100};
101
102int build_id__sprintf(const struct build_id *build_id, char *bf)
103{
104	char *bid = bf;
105	const u8 *raw = build_id->data;
106	size_t i;
107
108	bf[0] = 0x0;
109
110	for (i = 0; i < build_id->size; ++i) {
111		sprintf(bid, "%02x", *raw);
112		++raw;
113		bid += 2;
114	}
115
116	return (bid - bf) + 1;
117}
118
119int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id)
120{
121	char notes[PATH_MAX];
122	struct build_id bid;
123	int ret;
124
125	if (!root_dir)
126		root_dir = "";
127
128	scnprintf(notes, sizeof(notes), "%s/sys/kernel/notes", root_dir);
129
130	ret = sysfs__read_build_id(notes, &bid);
131	if (ret < 0)
132		return ret;
133
134	return build_id__sprintf(&bid, sbuild_id);
135}
136
137int filename__sprintf_build_id(const char *pathname, char *sbuild_id)
138{
139	struct build_id bid;
140	int ret;
141
142	ret = filename__read_build_id(pathname, &bid);
143	if (ret < 0)
144		return ret;
145
146	return build_id__sprintf(&bid, sbuild_id);
147}
148
149/* asnprintf consolidates asprintf and snprintf */
150static int asnprintf(char **strp, size_t size, const char *fmt, ...)
151{
152	va_list ap;
153	int ret;
154
155	if (!strp)
156		return -EINVAL;
157
158	va_start(ap, fmt);
159	if (*strp)
160		ret = vsnprintf(*strp, size, fmt, ap);
161	else
162		ret = vasprintf(strp, fmt, ap);
163	va_end(ap);
164
165	return ret;
166}
167
168char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
169				    size_t size)
170{
171	bool retry_old = true;
172
173	snprintf(bf, size, "%s/%s/%s/kallsyms",
174		 buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
175retry:
176	if (!access(bf, F_OK))
177		return bf;
178	if (retry_old) {
179		/* Try old style kallsyms cache */
180		snprintf(bf, size, "%s/%s/%s",
181			 buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
182		retry_old = false;
183		goto retry;
184	}
185
186	return NULL;
187}
188
189char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size)
190{
191	char *tmp = bf;
192	int ret = asnprintf(&bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
193			    sbuild_id, sbuild_id + 2);
194	if (ret < 0 || (tmp && size < (unsigned int)ret))
195		return NULL;
196	return bf;
197}
198
199/* The caller is responsible to free the returned buffer. */
200char *build_id_cache__origname(const char *sbuild_id)
201{
202	char *linkname;
203	char buf[PATH_MAX];
204	char *ret = NULL, *p;
205	size_t offs = 5;	/* == strlen("../..") */
206	ssize_t len;
207
208	linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
209	if (!linkname)
210		return NULL;
211
212	len = readlink(linkname, buf, sizeof(buf) - 1);
213	if (len <= 0)
214		goto out;
215	buf[len] = '\0';
216
217	/* The link should be "../..<origpath>/<sbuild_id>" */
218	p = strrchr(buf, '/');	/* Cut off the "/<sbuild_id>" */
219	if (p && (p > buf + offs)) {
220		*p = '\0';
221		if (buf[offs + 1] == '[')
222			offs++;	/*
223				 * This is a DSO name, like [kernel.kallsyms].
224				 * Skip the first '/', since this is not the
225				 * cache of a regular file.
226				 */
227		ret = strdup(buf + offs);	/* Skip "../..[/]" */
228	}
229out:
230	free(linkname);
231	return ret;
232}
233
234/* Check if the given build_id cache is valid on current running system */
235static bool build_id_cache__valid_id(char *sbuild_id)
236{
237	char real_sbuild_id[SBUILD_ID_SIZE] = "";
238	char *pathname;
239	int ret = 0;
240	bool result = false;
241
242	pathname = build_id_cache__origname(sbuild_id);
243	if (!pathname)
244		return false;
245
246	if (!strcmp(pathname, DSO__NAME_KALLSYMS))
247		ret = sysfs__sprintf_build_id("/", real_sbuild_id);
248	else if (pathname[0] == '/')
249		ret = filename__sprintf_build_id(pathname, real_sbuild_id);
250	else
251		ret = -EINVAL;	/* Should we support other special DSO cache? */
252	if (ret >= 0)
253		result = (strcmp(sbuild_id, real_sbuild_id) == 0);
254	free(pathname);
255
256	return result;
257}
258
259static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso,
260					    bool is_debug)
261{
262	return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : (is_debug ?
263	    "debug" : "elf"));
264}
265
266char *__dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
267			       bool is_debug, bool is_kallsyms)
268{
269	bool is_vdso = dso__is_vdso((struct dso *)dso);
270	char sbuild_id[SBUILD_ID_SIZE];
271	char *linkname;
272	bool alloc = (bf == NULL);
273	int ret;
274
275	if (!dso->has_build_id)
276		return NULL;
277
278	build_id__sprintf(&dso->bid, sbuild_id);
279	linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
280	if (!linkname)
281		return NULL;
282
283	/* Check if old style build_id cache */
284	if (is_regular_file(linkname))
285		ret = asnprintf(&bf, size, "%s", linkname);
286	else
287		ret = asnprintf(&bf, size, "%s/%s", linkname,
288			 build_id_cache__basename(is_kallsyms, is_vdso,
289						  is_debug));
290	if (ret < 0 || (!alloc && size < (unsigned int)ret))
291		bf = NULL;
292	free(linkname);
293
294	return bf;
295}
296
297char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
298			     bool is_debug)
299{
300	bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
301
302	return __dso__build_id_filename(dso, bf, size, is_debug, is_kallsyms);
303}
304
305static int write_buildid(const char *name, size_t name_len, struct build_id *bid,
306			 pid_t pid, u16 misc, struct feat_fd *fd)
307{
308	int err;
309	struct perf_record_header_build_id b;
310	size_t len;
311
312	len = name_len + 1;
313	len = PERF_ALIGN(len, NAME_ALIGN);
314
315	memset(&b, 0, sizeof(b));
316	memcpy(&b.data, bid->data, bid->size);
317	b.size = (u8) bid->size;
318	misc |= PERF_RECORD_MISC_BUILD_ID_SIZE;
319	b.pid = pid;
320	b.header.misc = misc;
321	b.header.size = sizeof(b) + len;
322
323	err = do_write(fd, &b, sizeof(b));
324	if (err < 0)
325		return err;
326
327	return write_padded(fd, name, name_len + 1, len);
328}
329
330static int machine__write_buildid_table(struct machine *machine,
331					struct feat_fd *fd)
332{
333	int err = 0;
334	struct dso *pos;
335	u16 kmisc = PERF_RECORD_MISC_KERNEL,
336	    umisc = PERF_RECORD_MISC_USER;
337
338	if (!machine__is_host(machine)) {
339		kmisc = PERF_RECORD_MISC_GUEST_KERNEL;
340		umisc = PERF_RECORD_MISC_GUEST_USER;
341	}
342
343	dsos__for_each_with_build_id(pos, &machine->dsos.head) {
344		const char *name;
345		size_t name_len;
346		bool in_kernel = false;
347
348		if (!pos->hit && !dso__is_vdso(pos))
349			continue;
350
351		if (dso__is_vdso(pos)) {
352			name = pos->short_name;
353			name_len = pos->short_name_len;
354		} else if (dso__is_kcore(pos)) {
355			name = machine->mmap_name;
356			name_len = strlen(name);
357		} else {
358			name = pos->long_name;
359			name_len = pos->long_name_len;
360		}
361
362		in_kernel = pos->kernel ||
363				is_kernel_module(name,
364					PERF_RECORD_MISC_CPUMODE_UNKNOWN);
365		err = write_buildid(name, name_len, &pos->bid, machine->pid,
366				    in_kernel ? kmisc : umisc, fd);
367		if (err)
368			break;
369	}
370
371	return err;
372}
373
374int perf_session__write_buildid_table(struct perf_session *session,
375				      struct feat_fd *fd)
376{
377	struct rb_node *nd;
378	int err = machine__write_buildid_table(&session->machines.host, fd);
379
380	if (err)
381		return err;
382
383	for (nd = rb_first_cached(&session->machines.guests); nd;
384	     nd = rb_next(nd)) {
385		struct machine *pos = rb_entry(nd, struct machine, rb_node);
386		err = machine__write_buildid_table(pos, fd);
387		if (err)
388			break;
389	}
390	return err;
391}
392
393static int __dsos__hit_all(struct list_head *head)
394{
395	struct dso *pos;
396
397	list_for_each_entry(pos, head, node)
398		pos->hit = true;
399
400	return 0;
401}
402
403static int machine__hit_all_dsos(struct machine *machine)
404{
405	return __dsos__hit_all(&machine->dsos.head);
406}
407
408int dsos__hit_all(struct perf_session *session)
409{
410	struct rb_node *nd;
411	int err;
412
413	err = machine__hit_all_dsos(&session->machines.host);
414	if (err)
415		return err;
416
417	for (nd = rb_first_cached(&session->machines.guests); nd;
418	     nd = rb_next(nd)) {
419		struct machine *pos = rb_entry(nd, struct machine, rb_node);
420
421		err = machine__hit_all_dsos(pos);
422		if (err)
423			return err;
424	}
425
426	return 0;
427}
428
429void disable_buildid_cache(void)
430{
431	no_buildid_cache = true;
432}
433
434static bool lsdir_bid_head_filter(const char *name __maybe_unused,
435				  struct dirent *d)
436{
437	return (strlen(d->d_name) == 2) &&
438		isxdigit(d->d_name[0]) && isxdigit(d->d_name[1]);
439}
440
441static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
442				  struct dirent *d)
443{
444	int i = 0;
445	while (isxdigit(d->d_name[i]) && i < SBUILD_ID_SIZE - 3)
446		i++;
447	return (i >= SBUILD_ID_MIN_SIZE - 3) && (i <= SBUILD_ID_SIZE - 3) &&
448		(d->d_name[i] == '\0');
449}
450
451struct strlist *build_id_cache__list_all(bool validonly)
452{
453	struct strlist *toplist, *linklist = NULL, *bidlist;
454	struct str_node *nd, *nd2;
455	char *topdir, *linkdir = NULL;
456	char sbuild_id[SBUILD_ID_SIZE];
457
458	/* for filename__ functions */
459	if (validonly)
460		symbol__init(NULL);
461
462	/* Open the top-level directory */
463	if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
464		return NULL;
465
466	bidlist = strlist__new(NULL, NULL);
467	if (!bidlist)
468		goto out;
469
470	toplist = lsdir(topdir, lsdir_bid_head_filter);
471	if (!toplist) {
472		pr_debug("Error in lsdir(%s): %d\n", topdir, errno);
473		/* If there is no buildid cache, return an empty list */
474		if (errno == ENOENT)
475			goto out;
476		goto err_out;
477	}
478
479	strlist__for_each_entry(nd, toplist) {
480		if (asprintf(&linkdir, "%s/%s", topdir, nd->s) < 0)
481			goto err_out;
482		/* Open the lower-level directory */
483		linklist = lsdir(linkdir, lsdir_bid_tail_filter);
484		if (!linklist) {
485			pr_debug("Error in lsdir(%s): %d\n", linkdir, errno);
486			goto err_out;
487		}
488		strlist__for_each_entry(nd2, linklist) {
489			if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
490				     nd->s, nd2->s) > SBUILD_ID_SIZE - 1)
491				goto err_out;
492			if (validonly && !build_id_cache__valid_id(sbuild_id))
493				continue;
494			if (strlist__add(bidlist, sbuild_id) < 0)
495				goto err_out;
496		}
497		strlist__delete(linklist);
498		zfree(&linkdir);
499	}
500
501out_free:
502	strlist__delete(toplist);
503out:
504	free(topdir);
505
506	return bidlist;
507
508err_out:
509	strlist__delete(linklist);
510	zfree(&linkdir);
511	strlist__delete(bidlist);
512	bidlist = NULL;
513	goto out_free;
514}
515
516static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)
517{
518	size_t i;
519
520	for (i = 0; i < len; i++) {
521		if (!isxdigit(maybe_sbuild_id[i]))
522			return false;
523	}
524	return true;
525}
526
527/* Return the valid complete build-id */
528char *build_id_cache__complement(const char *incomplete_sbuild_id)
529{
530	struct strlist *bidlist;
531	struct str_node *nd, *cand = NULL;
532	char *sbuild_id = NULL;
533	size_t len = strlen(incomplete_sbuild_id);
534
535	if (len >= SBUILD_ID_SIZE ||
536	    !str_is_build_id(incomplete_sbuild_id, len))
537		return NULL;
538
539	bidlist = build_id_cache__list_all(true);
540	if (!bidlist)
541		return NULL;
542
543	strlist__for_each_entry(nd, bidlist) {
544		if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)
545			continue;
546		if (cand) {	/* Error: There are more than 2 candidates. */
547			cand = NULL;
548			break;
549		}
550		cand = nd;
551	}
552	if (cand)
553		sbuild_id = strdup(cand->s);
554	strlist__delete(bidlist);
555
556	return sbuild_id;
557}
558
559char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
560			       struct nsinfo *nsi, bool is_kallsyms,
561			       bool is_vdso)
562{
563	char *realname = NULL, *filename;
564	bool slash = is_kallsyms || is_vdso;
565
566	if (!slash)
567		realname = nsinfo__realpath(name, nsi);
568
569	if (asprintf(&filename, "%s%s%s%s%s", buildid_dir, slash ? "/" : "",
570		     is_vdso ? DSO__NAME_VDSO : (realname ? realname : name),
571		     sbuild_id ? "/" : "", sbuild_id ?: "") < 0)
572		filename = NULL;
573
574	free(realname);
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}
1023