xref: /openbmc/linux/tools/perf/util/build-id.c (revision e0a45cda)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * build-id.c
4  *
5  * build-id support
6  *
7  * Copyright (C) 2009, 2010 Red Hat Inc.
8  * Copyright (C) 2009, 2010 Arnaldo Carvalho de Melo <acme@redhat.com>
9  */
10 #include "util.h" // lsdir(), mkdir_p(), rm_rf()
11 #include <dirent.h>
12 #include <errno.h>
13 #include <stdio.h>
14 #include <sys/stat.h>
15 #include <sys/types.h>
16 #include "util/copyfile.h"
17 #include "dso.h"
18 #include "build-id.h"
19 #include "event.h"
20 #include "namespaces.h"
21 #include "map.h"
22 #include "symbol.h"
23 #include "thread.h"
24 #include <linux/kernel.h>
25 #include "debug.h"
26 #include "session.h"
27 #include "tool.h"
28 #include "header.h"
29 #include "vdso.h"
30 #include "path.h"
31 #include "probe-file.h"
32 #include "strlist.h"
33 
34 #ifdef HAVE_DEBUGINFOD_SUPPORT
35 #include <elfutils/debuginfod.h>
36 #endif
37 
38 #include <linux/ctype.h>
39 #include <linux/zalloc.h>
40 #include <asm/bug.h>
41 
42 static bool no_buildid_cache;
43 
44 int build_id__mark_dso_hit(struct perf_tool *tool __maybe_unused,
45 			   union perf_event *event,
46 			   struct perf_sample *sample,
47 			   struct evsel *evsel __maybe_unused,
48 			   struct machine *machine)
49 {
50 	struct addr_location al;
51 	struct thread *thread = machine__findnew_thread(machine, sample->pid,
52 							sample->tid);
53 
54 	if (thread == NULL) {
55 		pr_err("problem processing %d event, skipping it.\n",
56 			event->header.type);
57 		return -1;
58 	}
59 
60 	if (thread__find_map(thread, sample->cpumode, sample->ip, &al))
61 		al.map->dso->hit = 1;
62 
63 	thread__put(thread);
64 	return 0;
65 }
66 
67 static int perf_event__exit_del_thread(struct perf_tool *tool __maybe_unused,
68 				       union perf_event *event,
69 				       struct perf_sample *sample
70 				       __maybe_unused,
71 				       struct machine *machine)
72 {
73 	struct thread *thread = machine__findnew_thread(machine,
74 							event->fork.pid,
75 							event->fork.tid);
76 
77 	dump_printf("(%d:%d):(%d:%d)\n", event->fork.pid, event->fork.tid,
78 		    event->fork.ppid, event->fork.ptid);
79 
80 	if (thread) {
81 		machine__remove_thread(machine, thread);
82 		thread__put(thread);
83 	}
84 
85 	return 0;
86 }
87 
88 struct perf_tool build_id__mark_dso_hit_ops = {
89 	.sample	= build_id__mark_dso_hit,
90 	.mmap	= perf_event__process_mmap,
91 	.mmap2	= perf_event__process_mmap2,
92 	.fork	= perf_event__process_fork,
93 	.exit	= perf_event__exit_del_thread,
94 	.attr		 = perf_event__process_attr,
95 	.build_id	 = perf_event__process_build_id,
96 	.ordered_events	 = true,
97 };
98 
99 int build_id__sprintf(const struct build_id *build_id, char *bf)
100 {
101 	char *bid = bf;
102 	const u8 *raw = build_id->data;
103 	size_t i;
104 
105 	bf[0] = 0x0;
106 
107 	for (i = 0; i < build_id->size; ++i) {
108 		sprintf(bid, "%02x", *raw);
109 		++raw;
110 		bid += 2;
111 	}
112 
113 	return (bid - bf) + 1;
114 }
115 
116 int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id)
117 {
118 	char notes[PATH_MAX];
119 	struct build_id bid;
120 	int ret;
121 
122 	if (!root_dir)
123 		root_dir = "";
124 
125 	scnprintf(notes, sizeof(notes), "%s/sys/kernel/notes", root_dir);
126 
127 	ret = sysfs__read_build_id(notes, &bid);
128 	if (ret < 0)
129 		return ret;
130 
131 	return build_id__sprintf(&bid, sbuild_id);
132 }
133 
134 int filename__sprintf_build_id(const char *pathname, char *sbuild_id)
135 {
136 	struct build_id bid;
137 	int ret;
138 
139 	ret = filename__read_build_id(pathname, &bid);
140 	if (ret < 0)
141 		return ret;
142 
143 	return build_id__sprintf(&bid, sbuild_id);
144 }
145 
146 /* asnprintf consolidates asprintf and snprintf */
147 static int asnprintf(char **strp, size_t size, const char *fmt, ...)
148 {
149 	va_list ap;
150 	int ret;
151 
152 	if (!strp)
153 		return -EINVAL;
154 
155 	va_start(ap, fmt);
156 	if (*strp)
157 		ret = vsnprintf(*strp, size, fmt, ap);
158 	else
159 		ret = vasprintf(strp, fmt, ap);
160 	va_end(ap);
161 
162 	return ret;
163 }
164 
165 char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
166 				    size_t size)
167 {
168 	bool retry_old = true;
169 
170 	snprintf(bf, size, "%s/%s/%s/kallsyms",
171 		 buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
172 retry:
173 	if (!access(bf, F_OK))
174 		return bf;
175 	if (retry_old) {
176 		/* Try old style kallsyms cache */
177 		snprintf(bf, size, "%s/%s/%s",
178 			 buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
179 		retry_old = false;
180 		goto retry;
181 	}
182 
183 	return NULL;
184 }
185 
186 char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size)
187 {
188 	char *tmp = bf;
189 	int ret = asnprintf(&bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
190 			    sbuild_id, sbuild_id + 2);
191 	if (ret < 0 || (tmp && size < (unsigned int)ret))
192 		return NULL;
193 	return bf;
194 }
195 
196 /* The caller is responsible to free the returned buffer. */
197 char *build_id_cache__origname(const char *sbuild_id)
198 {
199 	char *linkname;
200 	char buf[PATH_MAX];
201 	char *ret = NULL, *p;
202 	size_t offs = 5;	/* == strlen("../..") */
203 	ssize_t len;
204 
205 	linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
206 	if (!linkname)
207 		return NULL;
208 
209 	len = readlink(linkname, buf, sizeof(buf) - 1);
210 	if (len <= 0)
211 		goto out;
212 	buf[len] = '\0';
213 
214 	/* The link should be "../..<origpath>/<sbuild_id>" */
215 	p = strrchr(buf, '/');	/* Cut off the "/<sbuild_id>" */
216 	if (p && (p > buf + offs)) {
217 		*p = '\0';
218 		if (buf[offs + 1] == '[')
219 			offs++;	/*
220 				 * This is a DSO name, like [kernel.kallsyms].
221 				 * Skip the first '/', since this is not the
222 				 * cache of a regular file.
223 				 */
224 		ret = strdup(buf + offs);	/* Skip "../..[/]" */
225 	}
226 out:
227 	free(linkname);
228 	return ret;
229 }
230 
231 /* Check if the given build_id cache is valid on current running system */
232 static bool build_id_cache__valid_id(char *sbuild_id)
233 {
234 	char real_sbuild_id[SBUILD_ID_SIZE] = "";
235 	char *pathname;
236 	int ret = 0;
237 	bool result = false;
238 
239 	pathname = build_id_cache__origname(sbuild_id);
240 	if (!pathname)
241 		return false;
242 
243 	if (!strcmp(pathname, DSO__NAME_KALLSYMS))
244 		ret = sysfs__sprintf_build_id("/", real_sbuild_id);
245 	else if (pathname[0] == '/')
246 		ret = filename__sprintf_build_id(pathname, real_sbuild_id);
247 	else
248 		ret = -EINVAL;	/* Should we support other special DSO cache? */
249 	if (ret >= 0)
250 		result = (strcmp(sbuild_id, real_sbuild_id) == 0);
251 	free(pathname);
252 
253 	return result;
254 }
255 
256 static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso,
257 					    bool is_debug)
258 {
259 	return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : (is_debug ?
260 	    "debug" : "elf"));
261 }
262 
263 char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
264 			     bool is_debug)
265 {
266 	bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
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 
295 #define dsos__for_each_with_build_id(pos, head)	\
296 	list_for_each_entry(pos, head, node)	\
297 		if (!pos->has_build_id)		\
298 			continue;		\
299 		else
300 
301 static int write_buildid(const char *name, size_t name_len, struct build_id *bid,
302 			 pid_t pid, u16 misc, struct feat_fd *fd)
303 {
304 	int err;
305 	struct perf_record_header_build_id b;
306 	size_t len;
307 
308 	len = name_len + 1;
309 	len = PERF_ALIGN(len, NAME_ALIGN);
310 
311 	memset(&b, 0, sizeof(b));
312 	memcpy(&b.data, bid->data, bid->size);
313 	b.size = (u8) bid->size;
314 	misc |= PERF_RECORD_MISC_BUILD_ID_SIZE;
315 	b.pid = pid;
316 	b.header.misc = misc;
317 	b.header.size = sizeof(b) + len;
318 
319 	err = do_write(fd, &b, sizeof(b));
320 	if (err < 0)
321 		return err;
322 
323 	return write_padded(fd, name, name_len + 1, len);
324 }
325 
326 static int machine__write_buildid_table(struct machine *machine,
327 					struct feat_fd *fd)
328 {
329 	int err = 0;
330 	struct dso *pos;
331 	u16 kmisc = PERF_RECORD_MISC_KERNEL,
332 	    umisc = PERF_RECORD_MISC_USER;
333 
334 	if (!machine__is_host(machine)) {
335 		kmisc = PERF_RECORD_MISC_GUEST_KERNEL;
336 		umisc = PERF_RECORD_MISC_GUEST_USER;
337 	}
338 
339 	dsos__for_each_with_build_id(pos, &machine->dsos.head) {
340 		const char *name;
341 		size_t name_len;
342 		bool in_kernel = false;
343 
344 		if (!pos->hit && !dso__is_vdso(pos))
345 			continue;
346 
347 		if (dso__is_vdso(pos)) {
348 			name = pos->short_name;
349 			name_len = pos->short_name_len;
350 		} else if (dso__is_kcore(pos)) {
351 			name = machine->mmap_name;
352 			name_len = strlen(name);
353 		} else {
354 			name = pos->long_name;
355 			name_len = pos->long_name_len;
356 		}
357 
358 		in_kernel = pos->kernel ||
359 				is_kernel_module(name,
360 					PERF_RECORD_MISC_CPUMODE_UNKNOWN);
361 		err = write_buildid(name, name_len, &pos->bid, machine->pid,
362 				    in_kernel ? kmisc : umisc, fd);
363 		if (err)
364 			break;
365 	}
366 
367 	return err;
368 }
369 
370 int perf_session__write_buildid_table(struct perf_session *session,
371 				      struct feat_fd *fd)
372 {
373 	struct rb_node *nd;
374 	int err = machine__write_buildid_table(&session->machines.host, fd);
375 
376 	if (err)
377 		return err;
378 
379 	for (nd = rb_first_cached(&session->machines.guests); nd;
380 	     nd = rb_next(nd)) {
381 		struct machine *pos = rb_entry(nd, struct machine, rb_node);
382 		err = machine__write_buildid_table(pos, fd);
383 		if (err)
384 			break;
385 	}
386 	return err;
387 }
388 
389 static int __dsos__hit_all(struct list_head *head)
390 {
391 	struct dso *pos;
392 
393 	list_for_each_entry(pos, head, node)
394 		pos->hit = true;
395 
396 	return 0;
397 }
398 
399 static int machine__hit_all_dsos(struct machine *machine)
400 {
401 	return __dsos__hit_all(&machine->dsos.head);
402 }
403 
404 int dsos__hit_all(struct perf_session *session)
405 {
406 	struct rb_node *nd;
407 	int err;
408 
409 	err = machine__hit_all_dsos(&session->machines.host);
410 	if (err)
411 		return err;
412 
413 	for (nd = rb_first_cached(&session->machines.guests); nd;
414 	     nd = rb_next(nd)) {
415 		struct machine *pos = rb_entry(nd, struct machine, rb_node);
416 
417 		err = machine__hit_all_dsos(pos);
418 		if (err)
419 			return err;
420 	}
421 
422 	return 0;
423 }
424 
425 void disable_buildid_cache(void)
426 {
427 	no_buildid_cache = true;
428 }
429 
430 static bool lsdir_bid_head_filter(const char *name __maybe_unused,
431 				  struct dirent *d)
432 {
433 	return (strlen(d->d_name) == 2) &&
434 		isxdigit(d->d_name[0]) && isxdigit(d->d_name[1]);
435 }
436 
437 static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
438 				  struct dirent *d)
439 {
440 	int i = 0;
441 	while (isxdigit(d->d_name[i]) && i < SBUILD_ID_SIZE - 3)
442 		i++;
443 	return (i == SBUILD_ID_SIZE - 3) && (d->d_name[i] == '\0');
444 }
445 
446 struct strlist *build_id_cache__list_all(bool validonly)
447 {
448 	struct strlist *toplist, *linklist = NULL, *bidlist;
449 	struct str_node *nd, *nd2;
450 	char *topdir, *linkdir = NULL;
451 	char sbuild_id[SBUILD_ID_SIZE];
452 
453 	/* for filename__ functions */
454 	if (validonly)
455 		symbol__init(NULL);
456 
457 	/* Open the top-level directory */
458 	if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
459 		return NULL;
460 
461 	bidlist = strlist__new(NULL, NULL);
462 	if (!bidlist)
463 		goto out;
464 
465 	toplist = lsdir(topdir, lsdir_bid_head_filter);
466 	if (!toplist) {
467 		pr_debug("Error in lsdir(%s): %d\n", topdir, errno);
468 		/* If there is no buildid cache, return an empty list */
469 		if (errno == ENOENT)
470 			goto out;
471 		goto err_out;
472 	}
473 
474 	strlist__for_each_entry(nd, toplist) {
475 		if (asprintf(&linkdir, "%s/%s", topdir, nd->s) < 0)
476 			goto err_out;
477 		/* Open the lower-level directory */
478 		linklist = lsdir(linkdir, lsdir_bid_tail_filter);
479 		if (!linklist) {
480 			pr_debug("Error in lsdir(%s): %d\n", linkdir, errno);
481 			goto err_out;
482 		}
483 		strlist__for_each_entry(nd2, linklist) {
484 			if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
485 				     nd->s, nd2->s) != SBUILD_ID_SIZE - 1)
486 				goto err_out;
487 			if (validonly && !build_id_cache__valid_id(sbuild_id))
488 				continue;
489 			if (strlist__add(bidlist, sbuild_id) < 0)
490 				goto err_out;
491 		}
492 		strlist__delete(linklist);
493 		zfree(&linkdir);
494 	}
495 
496 out_free:
497 	strlist__delete(toplist);
498 out:
499 	free(topdir);
500 
501 	return bidlist;
502 
503 err_out:
504 	strlist__delete(linklist);
505 	zfree(&linkdir);
506 	strlist__delete(bidlist);
507 	bidlist = NULL;
508 	goto out_free;
509 }
510 
511 static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)
512 {
513 	size_t i;
514 
515 	for (i = 0; i < len; i++) {
516 		if (!isxdigit(maybe_sbuild_id[i]))
517 			return false;
518 	}
519 	return true;
520 }
521 
522 /* Return the valid complete build-id */
523 char *build_id_cache__complement(const char *incomplete_sbuild_id)
524 {
525 	struct strlist *bidlist;
526 	struct str_node *nd, *cand = NULL;
527 	char *sbuild_id = NULL;
528 	size_t len = strlen(incomplete_sbuild_id);
529 
530 	if (len >= SBUILD_ID_SIZE ||
531 	    !str_is_build_id(incomplete_sbuild_id, len))
532 		return NULL;
533 
534 	bidlist = build_id_cache__list_all(true);
535 	if (!bidlist)
536 		return NULL;
537 
538 	strlist__for_each_entry(nd, bidlist) {
539 		if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)
540 			continue;
541 		if (cand) {	/* Error: There are more than 2 candidates. */
542 			cand = NULL;
543 			break;
544 		}
545 		cand = nd;
546 	}
547 	if (cand)
548 		sbuild_id = strdup(cand->s);
549 	strlist__delete(bidlist);
550 
551 	return sbuild_id;
552 }
553 
554 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
555 			       struct nsinfo *nsi, bool is_kallsyms,
556 			       bool is_vdso)
557 {
558 	char *realname = (char *)name, *filename;
559 	bool slash = is_kallsyms || is_vdso;
560 
561 	if (!slash) {
562 		realname = nsinfo__realpath(name, nsi);
563 		if (!realname)
564 			return NULL;
565 	}
566 
567 	if (asprintf(&filename, "%s%s%s%s%s", buildid_dir, slash ? "/" : "",
568 		     is_vdso ? DSO__NAME_VDSO : realname,
569 		     sbuild_id ? "/" : "", sbuild_id ?: "") < 0)
570 		filename = NULL;
571 
572 	if (!slash)
573 		free(realname);
574 
575 	return filename;
576 }
577 
578 int 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)
597 static 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 
624 static char *build_id_cache__find_debug(const char *sbuild_id,
625 					struct nsinfo *nsi)
626 {
627 	char *realname = NULL;
628 	char *debugfile;
629 	struct nscookie nsc;
630 	size_t len = 0;
631 
632 	debugfile = calloc(1, PATH_MAX);
633 	if (!debugfile)
634 		goto out;
635 
636 	len = __symbol__join_symfs(debugfile, PATH_MAX,
637 				   "/usr/lib/debug/.build-id/");
638 	snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,
639 		 sbuild_id + 2);
640 
641 	nsinfo__mountns_enter(nsi, &nsc);
642 	realname = realpath(debugfile, NULL);
643 	if (realname && access(realname, R_OK))
644 		zfree(&realname);
645 	nsinfo__mountns_exit(&nsc);
646 
647 #ifdef HAVE_DEBUGINFOD_SUPPORT
648         if (realname == NULL) {
649                 debuginfod_client* c = debuginfod_begin();
650                 if (c != NULL) {
651                         int fd = debuginfod_find_debuginfo(c,
652                                                            (const unsigned char*)sbuild_id, 0,
653                                                            &realname);
654                         if (fd >= 0)
655                                 close(fd); /* retaining reference by realname */
656                         debuginfod_end(c);
657                 }
658         }
659 #endif
660 
661 out:
662 	free(debugfile);
663 	return realname;
664 }
665 
666 int build_id_cache__add_s(const char *sbuild_id, const char *name,
667 			  struct nsinfo *nsi, bool is_kallsyms, bool is_vdso)
668 {
669 	const size_t size = PATH_MAX;
670 	char *realname = NULL, *filename = NULL, *dir_name = NULL,
671 	     *linkname = zalloc(size), *tmp;
672 	char *debugfile = NULL;
673 	int err = -1;
674 
675 	if (!is_kallsyms) {
676 		if (!is_vdso)
677 			realname = nsinfo__realpath(name, nsi);
678 		else
679 			realname = realpath(name, NULL);
680 		if (!realname)
681 			goto out_free;
682 	}
683 
684 	dir_name = build_id_cache__cachedir(sbuild_id, name, nsi, is_kallsyms,
685 					    is_vdso);
686 	if (!dir_name)
687 		goto out_free;
688 
689 	/* Remove old style build-id cache */
690 	if (is_regular_file(dir_name))
691 		if (unlink(dir_name))
692 			goto out_free;
693 
694 	if (mkdir_p(dir_name, 0755))
695 		goto out_free;
696 
697 	/* Save the allocated buildid dirname */
698 	if (asprintf(&filename, "%s/%s", dir_name,
699 		     build_id_cache__basename(is_kallsyms, is_vdso,
700 		     false)) < 0) {
701 		filename = NULL;
702 		goto out_free;
703 	}
704 
705 	if (access(filename, F_OK)) {
706 		if (is_kallsyms) {
707 			if (copyfile("/proc/kallsyms", filename))
708 				goto out_free;
709 		} else if (nsi && nsi->need_setns) {
710 			if (copyfile_ns(name, filename, nsi))
711 				goto out_free;
712 		} else if (link(realname, filename) && errno != EEXIST &&
713 				copyfile(name, filename))
714 			goto out_free;
715 	}
716 
717 	/* Some binaries are stripped, but have .debug files with their symbol
718 	 * table.  Check to see if we can locate one of those, since the elf
719 	 * file itself may not be very useful to users of our tools without a
720 	 * symtab.
721 	 */
722 	if (!is_kallsyms && !is_vdso &&
723 	    strncmp(".ko", name + strlen(name) - 3, 3)) {
724 		debugfile = build_id_cache__find_debug(sbuild_id, nsi);
725 		if (debugfile) {
726 			zfree(&filename);
727 			if (asprintf(&filename, "%s/%s", dir_name,
728 			    build_id_cache__basename(false, false, true)) < 0) {
729 				filename = NULL;
730 				goto out_free;
731 			}
732 			if (access(filename, F_OK)) {
733 				if (nsi && nsi->need_setns) {
734 					if (copyfile_ns(debugfile, filename,
735 							nsi))
736 						goto out_free;
737 				} else if (link(debugfile, filename) &&
738 						errno != EEXIST &&
739 						copyfile(debugfile, filename))
740 					goto out_free;
741 			}
742 		}
743 	}
744 
745 	if (!build_id_cache__linkname(sbuild_id, linkname, size))
746 		goto out_free;
747 	tmp = strrchr(linkname, '/');
748 	*tmp = '\0';
749 
750 	if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
751 		goto out_free;
752 
753 	*tmp = '/';
754 	tmp = dir_name + strlen(buildid_dir) - 5;
755 	memcpy(tmp, "../..", 5);
756 
757 	if (symlink(tmp, linkname) == 0)
758 		err = 0;
759 
760 	/* Update SDT cache : error is just warned */
761 	if (realname &&
762 	    build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) < 0)
763 		pr_debug4("Failed to update/scan SDT cache for %s\n", realname);
764 
765 out_free:
766 	if (!is_kallsyms)
767 		free(realname);
768 	free(filename);
769 	free(debugfile);
770 	free(dir_name);
771 	free(linkname);
772 	return err;
773 }
774 
775 static int build_id_cache__add_b(const struct build_id *bid,
776 				 const char *name, struct nsinfo *nsi,
777 				 bool is_kallsyms, bool is_vdso)
778 {
779 	char sbuild_id[SBUILD_ID_SIZE];
780 
781 	build_id__sprintf(bid, sbuild_id);
782 
783 	return build_id_cache__add_s(sbuild_id, name, nsi, is_kallsyms,
784 				     is_vdso);
785 }
786 
787 bool build_id_cache__cached(const char *sbuild_id)
788 {
789 	bool ret = false;
790 	char *filename = build_id_cache__linkname(sbuild_id, NULL, 0);
791 
792 	if (filename && !access(filename, F_OK))
793 		ret = true;
794 	free(filename);
795 
796 	return ret;
797 }
798 
799 int build_id_cache__remove_s(const char *sbuild_id)
800 {
801 	const size_t size = PATH_MAX;
802 	char *filename = zalloc(size),
803 	     *linkname = zalloc(size), *tmp;
804 	int err = -1;
805 
806 	if (filename == NULL || linkname == NULL)
807 		goto out_free;
808 
809 	if (!build_id_cache__linkname(sbuild_id, linkname, size))
810 		goto out_free;
811 
812 	if (access(linkname, F_OK))
813 		goto out_free;
814 
815 	if (readlink(linkname, filename, size - 1) < 0)
816 		goto out_free;
817 
818 	if (unlink(linkname))
819 		goto out_free;
820 
821 	/*
822 	 * Since the link is relative, we must make it absolute:
823 	 */
824 	tmp = strrchr(linkname, '/') + 1;
825 	snprintf(tmp, size - (tmp - linkname), "%s", filename);
826 
827 	if (rm_rf(linkname))
828 		goto out_free;
829 
830 	err = 0;
831 out_free:
832 	free(filename);
833 	free(linkname);
834 	return err;
835 }
836 
837 static int dso__cache_build_id(struct dso *dso, struct machine *machine)
838 {
839 	bool is_kallsyms = dso__is_kallsyms(dso);
840 	bool is_vdso = dso__is_vdso(dso);
841 	const char *name = dso->long_name;
842 
843 	if (dso__is_kcore(dso)) {
844 		is_kallsyms = true;
845 		name = machine->mmap_name;
846 	}
847 	return build_id_cache__add_b(&dso->bid, name, dso->nsinfo,
848 				     is_kallsyms, is_vdso);
849 }
850 
851 static int __dsos__cache_build_ids(struct list_head *head,
852 				   struct machine *machine)
853 {
854 	struct dso *pos;
855 	int err = 0;
856 
857 	dsos__for_each_with_build_id(pos, head)
858 		if (dso__cache_build_id(pos, machine))
859 			err = -1;
860 
861 	return err;
862 }
863 
864 static int machine__cache_build_ids(struct machine *machine)
865 {
866 	return __dsos__cache_build_ids(&machine->dsos.head, machine);
867 }
868 
869 int perf_session__cache_build_ids(struct perf_session *session)
870 {
871 	struct rb_node *nd;
872 	int ret;
873 
874 	if (no_buildid_cache)
875 		return 0;
876 
877 	if (mkdir(buildid_dir, 0755) != 0 && errno != EEXIST)
878 		return -1;
879 
880 	ret = machine__cache_build_ids(&session->machines.host);
881 
882 	for (nd = rb_first_cached(&session->machines.guests); nd;
883 	     nd = rb_next(nd)) {
884 		struct machine *pos = rb_entry(nd, struct machine, rb_node);
885 		ret |= machine__cache_build_ids(pos);
886 	}
887 	return ret ? -1 : 0;
888 }
889 
890 static bool machine__read_build_ids(struct machine *machine, bool with_hits)
891 {
892 	return __dsos__read_build_ids(&machine->dsos.head, with_hits);
893 }
894 
895 bool perf_session__read_build_ids(struct perf_session *session, bool with_hits)
896 {
897 	struct rb_node *nd;
898 	bool ret = machine__read_build_ids(&session->machines.host, with_hits);
899 
900 	for (nd = rb_first_cached(&session->machines.guests); nd;
901 	     nd = rb_next(nd)) {
902 		struct machine *pos = rb_entry(nd, struct machine, rb_node);
903 		ret |= machine__read_build_ids(pos, with_hits);
904 	}
905 
906 	return ret;
907 }
908 
909 void build_id__init(struct build_id *bid, const u8 *data, size_t size)
910 {
911 	WARN_ON(size > BUILD_ID_SIZE);
912 	memcpy(bid->data, data, size);
913 	bid->size = size;
914 }
915