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1// SPDX-License-Identifier: GPL-2.02/*3 * build-id.c4 *5 * build-id support6 *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_SUPPORT35#include <elfutils/debuginfod.h>36#endif37 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(const 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		dso__set_hit(map__dso(al.map));64 65	addr_location__exit(&al);66	thread__put(thread);67	return 0;68}69 70int build_id__sprintf(const struct build_id *build_id, char *bf)71{72	char *bid = bf;73	const u8 *raw = build_id->data;74	size_t i;75 76	bf[0] = 0x0;77 78	for (i = 0; i < build_id->size; ++i) {79		sprintf(bid, "%02x", *raw);80		++raw;81		bid += 2;82	}83 84	return (bid - bf) + 1;85}86 87int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id)88{89	char notes[PATH_MAX];90	struct build_id bid;91	int ret;92 93	if (!root_dir)94		root_dir = "";95 96	scnprintf(notes, sizeof(notes), "%s/sys/kernel/notes", root_dir);97 98	ret = sysfs__read_build_id(notes, &bid);99	if (ret < 0)100		return ret;101 102	return build_id__sprintf(&bid, sbuild_id);103}104 105int filename__sprintf_build_id(const char *pathname, char *sbuild_id)106{107	struct build_id bid;108	int ret;109 110	ret = filename__read_build_id(pathname, &bid);111	if (ret < 0)112		return ret;113 114	return build_id__sprintf(&bid, sbuild_id);115}116 117/* asnprintf consolidates asprintf and snprintf */118static int asnprintf(char **strp, size_t size, const char *fmt, ...)119{120	va_list ap;121	int ret;122 123	if (!strp)124		return -EINVAL;125 126	va_start(ap, fmt);127	if (*strp)128		ret = vsnprintf(*strp, size, fmt, ap);129	else130		ret = vasprintf(strp, fmt, ap);131	va_end(ap);132 133	return ret;134}135 136char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,137				    size_t size)138{139	bool retry_old = true;140 141	snprintf(bf, size, "%s/%s/%s/kallsyms",142		 buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);143retry:144	if (!access(bf, F_OK))145		return bf;146	if (retry_old) {147		/* Try old style kallsyms cache */148		snprintf(bf, size, "%s/%s/%s",149			 buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);150		retry_old = false;151		goto retry;152	}153 154	return NULL;155}156 157char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size)158{159	char *tmp = bf;160	int ret = asnprintf(&bf, size, "%s/.build-id/%.2s/%s", buildid_dir,161			    sbuild_id, sbuild_id + 2);162	if (ret < 0 || (tmp && size < (unsigned int)ret))163		return NULL;164	return bf;165}166 167/* The caller is responsible to free the returned buffer. */168char *build_id_cache__origname(const char *sbuild_id)169{170	char *linkname;171	char buf[PATH_MAX];172	char *ret = NULL, *p;173	size_t offs = 5;	/* == strlen("../..") */174	ssize_t len;175 176	linkname = build_id_cache__linkname(sbuild_id, NULL, 0);177	if (!linkname)178		return NULL;179 180	len = readlink(linkname, buf, sizeof(buf) - 1);181	if (len <= 0)182		goto out;183	buf[len] = '\0';184 185	/* The link should be "../..<origpath>/<sbuild_id>" */186	p = strrchr(buf, '/');	/* Cut off the "/<sbuild_id>" */187	if (p && (p > buf + offs)) {188		*p = '\0';189		if (buf[offs + 1] == '[')190			offs++;	/*191				 * This is a DSO name, like [kernel.kallsyms].192				 * Skip the first '/', since this is not the193				 * cache of a regular file.194				 */195		ret = strdup(buf + offs);	/* Skip "../..[/]" */196	}197out:198	free(linkname);199	return ret;200}201 202/* Check if the given build_id cache is valid on current running system */203static bool build_id_cache__valid_id(char *sbuild_id)204{205	char real_sbuild_id[SBUILD_ID_SIZE] = "";206	char *pathname;207	int ret = 0;208	bool result = false;209 210	pathname = build_id_cache__origname(sbuild_id);211	if (!pathname)212		return false;213 214	if (!strcmp(pathname, DSO__NAME_KALLSYMS))215		ret = sysfs__sprintf_build_id("/", real_sbuild_id);216	else if (pathname[0] == '/')217		ret = filename__sprintf_build_id(pathname, real_sbuild_id);218	else219		ret = -EINVAL;	/* Should we support other special DSO cache? */220	if (ret >= 0)221		result = (strcmp(sbuild_id, real_sbuild_id) == 0);222	free(pathname);223 224	return result;225}226 227static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso,228					    bool is_debug)229{230	return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : (is_debug ?231	    "debug" : "elf"));232}233 234char *__dso__build_id_filename(const struct dso *dso, char *bf, size_t size,235			       bool is_debug, bool is_kallsyms)236{237	bool is_vdso = dso__is_vdso((struct dso *)dso);238	char sbuild_id[SBUILD_ID_SIZE];239	char *linkname;240	bool alloc = (bf == NULL);241	int ret;242 243	if (!dso__has_build_id(dso))244		return NULL;245 246	build_id__sprintf(dso__bid_const(dso), sbuild_id);247	linkname = build_id_cache__linkname(sbuild_id, NULL, 0);248	if (!linkname)249		return NULL;250 251	/* Check if old style build_id cache */252	if (is_regular_file(linkname))253		ret = asnprintf(&bf, size, "%s", linkname);254	else255		ret = asnprintf(&bf, size, "%s/%s", linkname,256			 build_id_cache__basename(is_kallsyms, is_vdso,257						  is_debug));258	if (ret < 0 || (!alloc && size < (unsigned int)ret))259		bf = NULL;260	free(linkname);261 262	return bf;263}264 265char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,266			     bool is_debug)267{268	bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);269 270	return __dso__build_id_filename(dso, bf, size, is_debug, is_kallsyms);271}272 273static int write_buildid(const char *name, size_t name_len, struct build_id *bid,274			 pid_t pid, u16 misc, struct feat_fd *fd)275{276	int err;277	struct perf_record_header_build_id b;278	size_t len;279 280	len = sizeof(b) + name_len + 1;281	len = PERF_ALIGN(len, sizeof(u64));282 283	memset(&b, 0, sizeof(b));284	memcpy(&b.data, bid->data, bid->size);285	b.size = (u8) bid->size;286	misc |= PERF_RECORD_MISC_BUILD_ID_SIZE;287	b.pid = pid;288	b.header.misc = misc;289	b.header.size = len;290 291	err = do_write(fd, &b, sizeof(b));292	if (err < 0)293		return err;294 295	return write_padded(fd, name, name_len + 1, len);296}297 298struct machine__write_buildid_table_cb_args {299	struct machine *machine;300	struct feat_fd *fd;301	u16 kmisc, umisc;302};303 304static int machine__write_buildid_table_cb(struct dso *dso, void *data)305{306	struct machine__write_buildid_table_cb_args *args = data;307	const char *name;308	size_t name_len;309	bool in_kernel = false;310 311	if (!dso__has_build_id(dso))312		return 0;313 314	if (!dso__hit(dso) && !dso__is_vdso(dso))315		return 0;316 317	if (dso__is_vdso(dso)) {318		name = dso__short_name(dso);319		name_len = dso__short_name_len(dso);320	} else if (dso__is_kcore(dso)) {321		name = args->machine->mmap_name;322		name_len = strlen(name);323	} else {324		name = dso__long_name(dso);325		name_len = dso__long_name_len(dso);326	}327 328	in_kernel = dso__kernel(dso) || is_kernel_module(name, PERF_RECORD_MISC_CPUMODE_UNKNOWN);329	return write_buildid(name, name_len, dso__bid(dso), args->machine->pid,330			     in_kernel ? args->kmisc : args->umisc, args->fd);331}332 333static int machine__write_buildid_table(struct machine *machine, struct feat_fd *fd)334{335	struct machine__write_buildid_table_cb_args args = {336		.machine = machine,337		.fd = fd,338		.kmisc = PERF_RECORD_MISC_KERNEL,339		.umisc = PERF_RECORD_MISC_USER,340	};341 342	if (!machine__is_host(machine)) {343		args.kmisc = PERF_RECORD_MISC_GUEST_KERNEL;344		args.umisc = PERF_RECORD_MISC_GUEST_USER;345	}346 347	return dsos__for_each_dso(&machine->dsos, machine__write_buildid_table_cb, &args);348}349 350int perf_session__write_buildid_table(struct perf_session *session,351				      struct feat_fd *fd)352{353	struct rb_node *nd;354	int err = machine__write_buildid_table(&session->machines.host, fd);355 356	if (err)357		return err;358 359	for (nd = rb_first_cached(&session->machines.guests); nd;360	     nd = rb_next(nd)) {361		struct machine *pos = rb_entry(nd, struct machine, rb_node);362		err = machine__write_buildid_table(pos, fd);363		if (err)364			break;365	}366	return err;367}368 369void disable_buildid_cache(void)370{371	no_buildid_cache = true;372}373 374static bool lsdir_bid_head_filter(const char *name __maybe_unused,375				  struct dirent *d)376{377	return (strlen(d->d_name) == 2) &&378		isxdigit(d->d_name[0]) && isxdigit(d->d_name[1]);379}380 381static bool lsdir_bid_tail_filter(const char *name __maybe_unused,382				  struct dirent *d)383{384	int i = 0;385	while (isxdigit(d->d_name[i]) && i < SBUILD_ID_SIZE - 3)386		i++;387	return (i >= SBUILD_ID_MIN_SIZE - 3) && (i <= SBUILD_ID_SIZE - 3) &&388		(d->d_name[i] == '\0');389}390 391struct strlist *build_id_cache__list_all(bool validonly)392{393	struct strlist *toplist, *linklist = NULL, *bidlist;394	struct str_node *nd, *nd2;395	char *topdir, *linkdir = NULL;396	char sbuild_id[SBUILD_ID_SIZE];397 398	/* for filename__ functions */399	if (validonly)400		symbol__init(NULL);401 402	/* Open the top-level directory */403	if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)404		return NULL;405 406	bidlist = strlist__new(NULL, NULL);407	if (!bidlist)408		goto out;409 410	toplist = lsdir(topdir, lsdir_bid_head_filter);411	if (!toplist) {412		pr_debug("Error in lsdir(%s): %d\n", topdir, errno);413		/* If there is no buildid cache, return an empty list */414		if (errno == ENOENT)415			goto out;416		goto err_out;417	}418 419	strlist__for_each_entry(nd, toplist) {420		if (asprintf(&linkdir, "%s/%s", topdir, nd->s) < 0)421			goto err_out;422		/* Open the lower-level directory */423		linklist = lsdir(linkdir, lsdir_bid_tail_filter);424		if (!linklist) {425			pr_debug("Error in lsdir(%s): %d\n", linkdir, errno);426			goto err_out;427		}428		strlist__for_each_entry(nd2, linklist) {429			if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",430				     nd->s, nd2->s) > SBUILD_ID_SIZE - 1)431				goto err_out;432			if (validonly && !build_id_cache__valid_id(sbuild_id))433				continue;434			if (strlist__add(bidlist, sbuild_id) < 0)435				goto err_out;436		}437		strlist__delete(linklist);438		zfree(&linkdir);439	}440 441out_free:442	strlist__delete(toplist);443out:444	free(topdir);445 446	return bidlist;447 448err_out:449	strlist__delete(linklist);450	zfree(&linkdir);451	strlist__delete(bidlist);452	bidlist = NULL;453	goto out_free;454}455 456static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)457{458	size_t i;459 460	for (i = 0; i < len; i++) {461		if (!isxdigit(maybe_sbuild_id[i]))462			return false;463	}464	return true;465}466 467/* Return the valid complete build-id */468char *build_id_cache__complement(const char *incomplete_sbuild_id)469{470	struct strlist *bidlist;471	struct str_node *nd, *cand = NULL;472	char *sbuild_id = NULL;473	size_t len = strlen(incomplete_sbuild_id);474 475	if (len >= SBUILD_ID_SIZE ||476	    !str_is_build_id(incomplete_sbuild_id, len))477		return NULL;478 479	bidlist = build_id_cache__list_all(true);480	if (!bidlist)481		return NULL;482 483	strlist__for_each_entry(nd, bidlist) {484		if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)485			continue;486		if (cand) {	/* Error: There are more than 2 candidates. */487			cand = NULL;488			break;489		}490		cand = nd;491	}492	if (cand)493		sbuild_id = strdup(cand->s);494	strlist__delete(bidlist);495 496	return sbuild_id;497}498 499char *build_id_cache__cachedir(const char *sbuild_id, const char *name,500			       struct nsinfo *nsi, bool is_kallsyms,501			       bool is_vdso)502{503	char *realname = NULL, *filename;504	bool slash = is_kallsyms || is_vdso;505 506	if (!slash)507		realname = nsinfo__realpath(name, nsi);508 509	if (asprintf(&filename, "%s%s%s%s%s", buildid_dir, slash ? "/" : "",510		     is_vdso ? DSO__NAME_VDSO : (realname ? realname : name),511		     sbuild_id ? "/" : "", sbuild_id ?: "") < 0)512		filename = NULL;513 514	free(realname);515	return filename;516}517 518int build_id_cache__list_build_ids(const char *pathname, struct nsinfo *nsi,519				   struct strlist **result)520{521	char *dir_name;522	int ret = 0;523 524	dir_name = build_id_cache__cachedir(NULL, pathname, nsi, false, false);525	if (!dir_name)526		return -ENOMEM;527 528	*result = lsdir(dir_name, lsdir_no_dot_filter);529	if (!*result)530		ret = -errno;531	free(dir_name);532 533	return ret;534}535 536#if defined(HAVE_LIBELF_SUPPORT) && defined(HAVE_GELF_GETNOTE_SUPPORT)537static int build_id_cache__add_sdt_cache(const char *sbuild_id,538					  const char *realname,539					  struct nsinfo *nsi)540{541	struct probe_cache *cache;542	int ret;543	struct nscookie nsc;544 545	cache = probe_cache__new(sbuild_id, nsi);546	if (!cache)547		return -1;548 549	nsinfo__mountns_enter(nsi, &nsc);550	ret = probe_cache__scan_sdt(cache, realname);551	nsinfo__mountns_exit(&nsc);552	if (ret >= 0) {553		pr_debug4("Found %d SDTs in %s\n", ret, realname);554		if (probe_cache__commit(cache) < 0)555			ret = -1;556	}557	probe_cache__delete(cache);558	return ret;559}560#else561#define build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) (0)562#endif563 564static char *build_id_cache__find_debug(const char *sbuild_id,565					struct nsinfo *nsi,566					const char *root_dir)567{568	const char *dirname = "/usr/lib/debug/.build-id/";569	char *realname = NULL;570	char dirbuf[PATH_MAX];571	char *debugfile;572	struct nscookie nsc;573	size_t len = 0;574 575	debugfile = calloc(1, PATH_MAX);576	if (!debugfile)577		goto out;578 579	if (root_dir) {580		path__join(dirbuf, PATH_MAX, root_dir, dirname);581		dirname = dirbuf;582	}583 584	len = __symbol__join_symfs(debugfile, PATH_MAX, dirname);585	snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,586		 sbuild_id + 2);587 588	nsinfo__mountns_enter(nsi, &nsc);589	realname = realpath(debugfile, NULL);590	if (realname && access(realname, R_OK))591		zfree(&realname);592	nsinfo__mountns_exit(&nsc);593 594#ifdef HAVE_DEBUGINFOD_SUPPORT595	if (realname == NULL) {596		debuginfod_client* c;597 598		pr_debug("Downloading debug info with build id %s\n", sbuild_id);599 600		c = debuginfod_begin();601		if (c != NULL) {602			int fd = debuginfod_find_debuginfo(c,603					(const unsigned char*)sbuild_id, 0,604					&realname);605			if (fd >= 0)606				close(fd); /* retaining reference by realname */607			debuginfod_end(c);608		}609	}610#endif611 612out:613	free(debugfile);614	return realname;615}616 617int618build_id_cache__add(const char *sbuild_id, const char *name, const char *realname,619		    struct nsinfo *nsi, bool is_kallsyms, bool is_vdso,620		    const char *proper_name, const char *root_dir)621{622	const size_t size = PATH_MAX;623	char *filename = NULL, *dir_name = NULL, *linkname = zalloc(size), *tmp;624	char *debugfile = NULL;625	int err = -1;626 627	if (!proper_name)628		proper_name = name;629 630	dir_name = build_id_cache__cachedir(sbuild_id, proper_name, nsi, is_kallsyms,631					    is_vdso);632	if (!dir_name)633		goto out_free;634 635	/* Remove old style build-id cache */636	if (is_regular_file(dir_name))637		if (unlink(dir_name))638			goto out_free;639 640	if (mkdir_p(dir_name, 0755))641		goto out_free;642 643	/* Save the allocated buildid dirname */644	if (asprintf(&filename, "%s/%s", dir_name,645		     build_id_cache__basename(is_kallsyms, is_vdso,646		     false)) < 0) {647		filename = NULL;648		goto out_free;649	}650 651	if (access(filename, F_OK)) {652		if (is_kallsyms) {653			if (copyfile("/proc/kallsyms", filename))654				goto out_free;655		} else if (nsi && nsinfo__need_setns(nsi)) {656			if (copyfile_ns(name, filename, nsi))657				goto out_free;658		} else if (link(realname, filename) && errno != EEXIST) {659			struct stat f_stat;660 661			if (!(stat(name, &f_stat) < 0) &&662					copyfile_mode(name, filename, f_stat.st_mode))663				goto out_free;664		}665	}666 667	/* Some binaries are stripped, but have .debug files with their symbol668	 * table.  Check to see if we can locate one of those, since the elf669	 * file itself may not be very useful to users of our tools without a670	 * symtab.671	 */672	if (!is_kallsyms && !is_vdso &&673	    strncmp(".ko", name + strlen(name) - 3, 3)) {674		debugfile = build_id_cache__find_debug(sbuild_id, nsi, root_dir);675		if (debugfile) {676			zfree(&filename);677			if (asprintf(&filename, "%s/%s", dir_name,678			    build_id_cache__basename(false, false, true)) < 0) {679				filename = NULL;680				goto out_free;681			}682			if (access(filename, F_OK)) {683				if (nsi && nsinfo__need_setns(nsi)) {684					if (copyfile_ns(debugfile, filename,685							nsi))686						goto out_free;687				} else if (link(debugfile, filename) &&688						errno != EEXIST &&689						copyfile(debugfile, filename))690					goto out_free;691			}692		}693	}694 695	if (!build_id_cache__linkname(sbuild_id, linkname, size))696		goto out_free;697	tmp = strrchr(linkname, '/');698	*tmp = '\0';699 700	if (access(linkname, X_OK) && mkdir_p(linkname, 0755))701		goto out_free;702 703	*tmp = '/';704	tmp = dir_name + strlen(buildid_dir) - 5;705	memcpy(tmp, "../..", 5);706 707	if (symlink(tmp, linkname) == 0) {708		err = 0;709	} else if (errno == EEXIST) {710		char path[PATH_MAX];711		ssize_t len;712 713		len = readlink(linkname, path, sizeof(path) - 1);714		if (len <= 0) {715			pr_err("Can't read link: %s\n", linkname);716			goto out_free;717		}718		path[len] = '\0';719 720		if (strcmp(tmp, path)) {721			pr_debug("build <%s> already linked to %s\n",722				 sbuild_id, linkname);723		}724		err = 0;725	}726 727	/* Update SDT cache : error is just warned */728	if (realname &&729	    build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) < 0)730		pr_debug4("Failed to update/scan SDT cache for %s\n", realname);731 732out_free:733	free(filename);734	free(debugfile);735	free(dir_name);736	free(linkname);737	return err;738}739 740int __build_id_cache__add_s(const char *sbuild_id, const char *name,741			    struct nsinfo *nsi, bool is_kallsyms, bool is_vdso,742			    const char *proper_name, const char *root_dir)743{744	char *realname = NULL;745	int err = -1;746 747	if (!is_kallsyms) {748		if (!is_vdso)749			realname = nsinfo__realpath(name, nsi);750		else751			realname = realpath(name, NULL);752		if (!realname)753			goto out_free;754	}755 756	err = build_id_cache__add(sbuild_id, name, realname, nsi,757				  is_kallsyms, is_vdso, proper_name, root_dir);758out_free:759	if (!is_kallsyms)760		free(realname);761	return err;762}763 764static int build_id_cache__add_b(const struct build_id *bid,765				 const char *name, struct nsinfo *nsi,766				 bool is_kallsyms, bool is_vdso,767				 const char *proper_name,768				 const char *root_dir)769{770	char sbuild_id[SBUILD_ID_SIZE];771 772	build_id__sprintf(bid, sbuild_id);773 774	return __build_id_cache__add_s(sbuild_id, name, nsi, is_kallsyms,775				       is_vdso, proper_name, root_dir);776}777 778bool build_id_cache__cached(const char *sbuild_id)779{780	bool ret = false;781	char *filename = build_id_cache__linkname(sbuild_id, NULL, 0);782 783	if (filename && !access(filename, F_OK))784		ret = true;785	free(filename);786 787	return ret;788}789 790int build_id_cache__remove_s(const char *sbuild_id)791{792	const size_t size = PATH_MAX;793	char *filename = zalloc(size),794	     *linkname = zalloc(size), *tmp;795	int err = -1;796 797	if (filename == NULL || linkname == NULL)798		goto out_free;799 800	if (!build_id_cache__linkname(sbuild_id, linkname, size))801		goto out_free;802 803	if (access(linkname, F_OK))804		goto out_free;805 806	if (readlink(linkname, filename, size - 1) < 0)807		goto out_free;808 809	if (unlink(linkname))810		goto out_free;811 812	/*813	 * Since the link is relative, we must make it absolute:814	 */815	tmp = strrchr(linkname, '/') + 1;816	snprintf(tmp, size - (tmp - linkname), "%s", filename);817 818	if (rm_rf(linkname))819		goto out_free;820 821	err = 0;822out_free:823	free(filename);824	free(linkname);825	return err;826}827 828static int filename__read_build_id_ns(const char *filename,829				      struct build_id *bid,830				      struct nsinfo *nsi)831{832	struct nscookie nsc;833	int ret;834 835	nsinfo__mountns_enter(nsi, &nsc);836	ret = filename__read_build_id(filename, bid);837	nsinfo__mountns_exit(&nsc);838 839	return ret;840}841 842static bool dso__build_id_mismatch(struct dso *dso, const char *name)843{844	struct build_id bid;845	bool ret = false;846 847	mutex_lock(dso__lock(dso));848	if (filename__read_build_id_ns(name, &bid, dso__nsinfo(dso)) >= 0)849		ret = !dso__build_id_equal(dso, &bid);850 851	mutex_unlock(dso__lock(dso));852 853	return ret;854}855 856static int dso__cache_build_id(struct dso *dso, struct machine *machine,857			       void *priv __maybe_unused)858{859	bool is_kallsyms = dso__is_kallsyms(dso);860	bool is_vdso = dso__is_vdso(dso);861	const char *name = dso__long_name(dso);862	const char *proper_name = NULL;863	const char *root_dir = NULL;864	char *allocated_name = NULL;865	int ret = 0;866 867	if (!dso__has_build_id(dso))868		return 0;869 870	if (dso__is_kcore(dso)) {871		is_kallsyms = true;872		name = machine->mmap_name;873	}874 875	if (!machine__is_host(machine)) {876		if (*machine->root_dir) {877			root_dir = machine->root_dir;878			ret = asprintf(&allocated_name, "%s/%s", root_dir, name);879			if (ret < 0)880				return ret;881			proper_name = name;882			name = allocated_name;883		} else if (is_kallsyms) {884			/* Cannot get guest kallsyms */885			return 0;886		}887	}888 889	if (!is_kallsyms && dso__build_id_mismatch(dso, name))890		goto out_free;891 892	mutex_lock(dso__lock(dso));893	ret = build_id_cache__add_b(dso__bid(dso), name, dso__nsinfo(dso),894				    is_kallsyms, is_vdso, proper_name, root_dir);895	mutex_unlock(dso__lock(dso));896out_free:897	free(allocated_name);898	return ret;899}900 901static int902machines__for_each_dso(struct machines *machines, machine__dso_t fn, void *priv)903{904	int ret = machine__for_each_dso(&machines->host, fn, priv);905	struct rb_node *nd;906 907	for (nd = rb_first_cached(&machines->guests); nd;908	     nd = rb_next(nd)) {909		struct machine *pos = rb_entry(nd, struct machine, rb_node);910 911		ret |= machine__for_each_dso(pos, fn, priv);912	}913	return ret ? -1 : 0;914}915 916int __perf_session__cache_build_ids(struct perf_session *session,917				    machine__dso_t fn, void *priv)918{919	if (no_buildid_cache)920		return 0;921 922	if (mkdir(buildid_dir, 0755) != 0 && errno != EEXIST)923		return -1;924 925	return machines__for_each_dso(&session->machines, fn, priv) ?  -1 : 0;926}927 928int perf_session__cache_build_ids(struct perf_session *session)929{930	return __perf_session__cache_build_ids(session, dso__cache_build_id, NULL);931}932 933static bool machine__read_build_ids(struct machine *machine, bool with_hits)934{935	return dsos__read_build_ids(&machine->dsos, with_hits);936}937 938bool perf_session__read_build_ids(struct perf_session *session, bool with_hits)939{940	struct rb_node *nd;941	bool ret = machine__read_build_ids(&session->machines.host, with_hits);942 943	for (nd = rb_first_cached(&session->machines.guests); nd;944	     nd = rb_next(nd)) {945		struct machine *pos = rb_entry(nd, struct machine, rb_node);946		ret |= machine__read_build_ids(pos, with_hits);947	}948 949	return ret;950}951 952void build_id__init(struct build_id *bid, const u8 *data, size_t size)953{954	WARN_ON(size > BUILD_ID_SIZE);955	memcpy(bid->data, data, size);956	bid->size = size;957}958 959bool build_id__is_defined(const struct build_id *bid)960{961	return bid && bid->size ? !!memchr_inv(bid->data, 0, bid->size) : false;962}963