tools/perf/util/build-id.c - kernel/bruno - Git at Google

 /*
  * build-id.c
  *
  * build-id support
  *
  * Copyright (C) 2009, 2010 Red Hat Inc.
  * Copyright (C) 2009, 2010 Arnaldo Carvalho de Melo <acme@redhat.com>
  */
 #include "util.h"
 #include <stdio.h>
 #include "build-id.h"
 #include "event.h"
 #include "symbol.h"
 #include <linux/kernel.h>
 #include "debug.h"
 #include "session.h"
 #include "tool.h"
 #include "header.h"
 #include "vdso.h"


 static bool no_buildid_cache;

 int build_id__mark_dso_hit(struct perf_tool *tool __maybe_unused,
 			   union perf_event *event,
 			   struct perf_sample *sample,
 			   struct perf_evsel *evsel __maybe_unused,
 			   struct machine *machine)
 {
 	struct addr_location al;
 	u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
 	struct thread *thread = machine__findnew_thread(machine, sample->pid,
 							sample->tid);

 	if (thread == NULL) {
 		pr_err("problem processing %d event, skipping it.\n",
 			event->header.type);
 		return -1;
 	}

 	thread__find_addr_map(thread, cpumode, MAP__FUNCTION, sample->ip, &al);

 	if (al.map != NULL)
 		al.map->dso->hit = 1;

 	return 0;
 }

 static int perf_event__exit_del_thread(struct perf_tool *tool __maybe_unused,
 				       union perf_event *event,
 				       struct perf_sample *sample
 				       __maybe_unused,
 				       struct machine *machine)
 {
 	struct thread *thread = machine__findnew_thread(machine,
 							event->fork.pid,
 							event->fork.tid);

 	dump_printf("(%d:%d):(%d:%d)\n", event->fork.pid, event->fork.tid,
 		    event->fork.ppid, event->fork.ptid);

 	if (thread) {
 		rb_erase(&thread->rb_node, &machine->threads);
 		machine->last_match = NULL;
 		thread__delete(thread);
 	}

 	return 0;
 }

 struct perf_tool build_id__mark_dso_hit_ops = {
 	.sample	= build_id__mark_dso_hit,
 	.mmap	= perf_event__process_mmap,
 	.mmap2	= perf_event__process_mmap2,
 	.fork	= perf_event__process_fork,
 	.exit	= perf_event__exit_del_thread,
 	.attr		 = perf_event__process_attr,
 	.build_id	 = perf_event__process_build_id,
 };

 int build_id__sprintf(const u8 *build_id, int len, char *bf)
 {
 	char *bid = bf;
 	const u8 *raw = build_id;
 	int i;

 	for (i = 0; i < len; ++i) {
 		sprintf(bid, "%02x", *raw);
 		++raw;
 		bid += 2;
 	}

 	return raw - build_id;
 }

 char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size)
 {
 	char build_id_hex[BUILD_ID_SIZE * 2 + 1];

 	if (!dso->has_build_id)
 		return NULL;

 	build_id__sprintf(dso->build_id, sizeof(dso->build_id), build_id_hex);
 	if (bf == NULL) {
 		if (asprintf(&bf, "%s/.build-id/%.2s/%s", buildid_dir,
 			     build_id_hex, build_id_hex + 2) < 0)
 			return NULL;
 	} else
 		snprintf(bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
 			 build_id_hex, build_id_hex + 2);
 	return bf;
 }

 #define dsos__for_each_with_build_id(pos, head)	\
 	list_for_each_entry(pos, head, node)	\
 		if (!pos->has_build_id)		\
 			continue;		\
 		else

 static int write_buildid(const char *name, size_t name_len, u8 *build_id,
 			 pid_t pid, u16 misc, int fd)
 {
 	int err;
 	struct build_id_event b;
 	size_t len;

 	len = name_len + 1;
 	len = PERF_ALIGN(len, NAME_ALIGN);

 	memset(&b, 0, sizeof(b));
 	memcpy(&b.build_id, build_id, BUILD_ID_SIZE);
 	b.pid = pid;
 	b.header.misc = misc;
 	b.header.size = sizeof(b) + len;

 	err = writen(fd, &b, sizeof(b));
 	if (err < 0)
 		return err;

 	return write_padded(fd, name, name_len + 1, len);
 }

 static int __dsos__write_buildid_table(struct list_head *head,
 				       struct machine *machine,
 				       pid_t pid, u16 misc, int fd)
 {
 	char nm[PATH_MAX];
 	struct dso *pos;

 	dsos__for_each_with_build_id(pos, head) {
 		int err;
 		const char *name;
 		size_t name_len;

 		if (!pos->hit)
 			continue;

 		if (dso__is_vdso(pos)) {
 			name = pos->short_name;
 			name_len = pos->short_name_len + 1;
 		} else if (dso__is_kcore(pos)) {
 			machine__mmap_name(machine, nm, sizeof(nm));
 			name = nm;
 			name_len = strlen(nm) + 1;
 		} else {
 			name = pos->long_name;
 			name_len = pos->long_name_len + 1;
 		}

 		err = write_buildid(name, name_len, pos->build_id,
 				    pid, misc, fd);
 		if (err)
 			return err;
 	}

 	return 0;
 }

 static int machine__write_buildid_table(struct machine *machine, int fd)
 {
 	int err;
 	u16 kmisc = PERF_RECORD_MISC_KERNEL,
 	    umisc = PERF_RECORD_MISC_USER;

 	if (!machine__is_host(machine)) {
 		kmisc = PERF_RECORD_MISC_GUEST_KERNEL;
 		umisc = PERF_RECORD_MISC_GUEST_USER;
 	}

 	err = __dsos__write_buildid_table(&machine->kernel_dsos.head, machine,
 					  machine->pid, kmisc, fd);
 	if (err == 0)
 		err = __dsos__write_buildid_table(&machine->user_dsos.head,
 						  machine, machine->pid, umisc,
 						  fd);
 	return err;
 }

 int perf_session__write_buildid_table(struct perf_session *session, int fd)
 {
 	struct rb_node *nd;
 	int err = machine__write_buildid_table(&session->machines.host, fd);

 	if (err)
 		return err;

 	for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
 		struct machine *pos = rb_entry(nd, struct machine, rb_node);
 		err = machine__write_buildid_table(pos, fd);
 		if (err)
 			break;
 	}
 	return err;
 }

 static int __dsos__hit_all(struct list_head *head)
 {
 	struct dso *pos;

 	list_for_each_entry(pos, head, node)
 		pos->hit = true;

 	return 0;
 }

 static int machine__hit_all_dsos(struct machine *machine)
 {
 	int err;

 	err = __dsos__hit_all(&machine->kernel_dsos.head);
 	if (err)
 		return err;

 	return __dsos__hit_all(&machine->user_dsos.head);
 }

 int dsos__hit_all(struct perf_session *session)
 {
 	struct rb_node *nd;
 	int err;

 	err = machine__hit_all_dsos(&session->machines.host);
 	if (err)
 		return err;

 	for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
 		struct machine *pos = rb_entry(nd, struct machine, rb_node);

 		err = machine__hit_all_dsos(pos);
 		if (err)
 			return err;
 	}

 	return 0;
 }

 void disable_buildid_cache(void)
 {
 	no_buildid_cache = true;
 }

 int build_id_cache__add_s(const char *sbuild_id, const char *debugdir,
 			  const char *name, bool is_kallsyms, bool is_vdso)
 {
 	const size_t size = PATH_MAX;
 	char *realname, *filename = zalloc(size),
 	     *linkname = zalloc(size), *targetname;
 	int len, err = -1;
 	bool slash = is_kallsyms || is_vdso;

 	if (is_kallsyms) {
 		if (symbol_conf.kptr_restrict) {
 			pr_debug("Not caching a kptr_restrict'ed /proc/kallsyms\n");
 			err = 0;
 			goto out_free;
 		}
 		realname = (char *) name;
 	} else
 		realname = realpath(name, NULL);

 	if (realname == NULL || filename == NULL || linkname == NULL)
 		goto out_free;

 	len = scnprintf(filename, size, "%s%s%s",
 		       debugdir, slash ? "/" : "",
 		       is_vdso ? DSO__NAME_VDSO : realname);
 	if (mkdir_p(filename, 0755))
 		goto out_free;

 	snprintf(filename + len, size - len, "/%s", sbuild_id);

 	if (access(filename, F_OK)) {
 		if (is_kallsyms) {
 			 if (copyfile("/proc/kallsyms", filename))
 				goto out_free;
 		} else if (link(realname, filename) && copyfile(name, filename))
 			goto out_free;
 	}

 	len = scnprintf(linkname, size, "%s/.build-id/%.2s",
 		       debugdir, sbuild_id);

 	if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
 		goto out_free;

 	snprintf(linkname + len, size - len, "/%s", sbuild_id + 2);
 	targetname = filename + strlen(debugdir) - 5;
 	memcpy(targetname, "../..", 5);

 	if (symlink(targetname, linkname) == 0)
 		err = 0;
 out_free:
 	if (!is_kallsyms)
 		free(realname);
 	free(filename);
 	free(linkname);
 	return err;
 }

 static int build_id_cache__add_b(const u8 *build_id, size_t build_id_size,
 				 const char *name, const char *debugdir,
 				 bool is_kallsyms, bool is_vdso)
 {
 	char sbuild_id[BUILD_ID_SIZE * 2 + 1];

 	build_id__sprintf(build_id, build_id_size, sbuild_id);

 	return build_id_cache__add_s(sbuild_id, debugdir, name,
 				     is_kallsyms, is_vdso);
 }

 int build_id_cache__remove_s(const char *sbuild_id, const char *debugdir)
 {
 	const size_t size = PATH_MAX;
 	char *filename = zalloc(size),
 	     *linkname = zalloc(size);
 	int err = -1;

 	if (filename == NULL || linkname == NULL)
 		goto out_free;

 	snprintf(linkname, size, "%s/.build-id/%.2s/%s",
 		 debugdir, sbuild_id, sbuild_id + 2);

 	if (access(linkname, F_OK))
 		goto out_free;

 	if (readlink(linkname, filename, size - 1) < 0)
 		goto out_free;

 	if (unlink(linkname))
 		goto out_free;

 	/*
 	 * Since the link is relative, we must make it absolute:
 	 */
 	snprintf(linkname, size, "%s/.build-id/%.2s/%s",
 		 debugdir, sbuild_id, filename);

 	if (unlink(linkname))
 		goto out_free;

 	err = 0;
 out_free:
 	free(filename);
 	free(linkname);
 	return err;
 }

 static int dso__cache_build_id(struct dso *dso, struct machine *machine,
 			       const char *debugdir)
 {
 	bool is_kallsyms = dso->kernel && dso->long_name[0] != '/';
 	bool is_vdso = dso__is_vdso(dso);
 	const char *name = dso->long_name;
 	char nm[PATH_MAX];

 	if (dso__is_kcore(dso)) {
 		is_kallsyms = true;
 		machine__mmap_name(machine, nm, sizeof(nm));
 		name = nm;
 	}
 	return build_id_cache__add_b(dso->build_id, sizeof(dso->build_id), name,
 				     debugdir, is_kallsyms, is_vdso);
 }

 static int __dsos__cache_build_ids(struct list_head *head,
 				   struct machine *machine, const char *debugdir)
 {
 	struct dso *pos;
 	int err = 0;

 	dsos__for_each_with_build_id(pos, head)
 		if (dso__cache_build_id(pos, machine, debugdir))
 			err = -1;

 	return err;
 }

 static int machine__cache_build_ids(struct machine *machine, const char *debugdir)
 {
 	int ret = __dsos__cache_build_ids(&machine->kernel_dsos.head, machine,
 					  debugdir);
 	ret |= __dsos__cache_build_ids(&machine->user_dsos.head, machine,
 				       debugdir);
 	return ret;
 }

 int perf_session__cache_build_ids(struct perf_session *session)
 {
 	struct rb_node *nd;
 	int ret;

 	if (no_buildid_cache)
 		return 0;

 	if (mkdir(buildid_dir, 0755) != 0 && errno != EEXIST)
 		return -1;

 	ret = machine__cache_build_ids(&session->machines.host, buildid_dir);

 	for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
 		struct machine *pos = rb_entry(nd, struct machine, rb_node);
 		ret |= machine__cache_build_ids(pos, buildid_dir);
 	}
 	return ret ? -1 : 0;
 }

 static bool machine__read_build_ids(struct machine *machine, bool with_hits)
 {
 	bool ret;

 	ret  = __dsos__read_build_ids(&machine->kernel_dsos.head, with_hits);
 	ret |= __dsos__read_build_ids(&machine->user_dsos.head, with_hits);
 	return ret;
 }

 bool perf_session__read_build_ids(struct perf_session *session, bool with_hits)
 {
 	struct rb_node *nd;
 	bool ret = machine__read_build_ids(&session->machines.host, with_hits);

 	for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
 		struct machine *pos = rb_entry(nd, struct machine, rb_node);
 		ret |= machine__read_build_ids(pos, with_hits);
 	}

 	return ret;
 }
	/*
	* build-id.c
	*
	* build-id support
	*
	* Copyright (C) 2009, 2010 Red Hat Inc.
	* Copyright (C) 2009, 2010 Arnaldo Carvalho de Melo <acme@redhat.com>
	*/
	#include "util.h"
	#include <stdio.h>
	#include "build-id.h"
	#include "event.h"
	#include "symbol.h"
	#include <linux/kernel.h>
	#include "debug.h"
	#include "session.h"
	#include "tool.h"
	#include "header.h"
	#include "vdso.h"


	static bool no_buildid_cache;

	int build_id__mark_dso_hit(struct perf_tool *tool __maybe_unused,
	union perf_event *event,
	struct perf_sample *sample,
	struct perf_evsel *evsel __maybe_unused,
	struct machine *machine)
	{
	struct addr_location al;
	u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
	struct thread *thread = machine__findnew_thread(machine, sample->pid,
	sample->tid);

	if (thread == NULL) {
	pr_err("problem processing %d event, skipping it.\n",
	event->header.type);
	return -1;
	}

	thread__find_addr_map(thread, cpumode, MAP__FUNCTION, sample->ip, &al);

	if (al.map != NULL)
	al.map->dso->hit = 1;

	return 0;
	}

	static int perf_event__exit_del_thread(struct perf_tool *tool __maybe_unused,
	union perf_event *event,
	struct perf_sample *sample
	__maybe_unused,
	struct machine *machine)
	{
	struct thread *thread = machine__findnew_thread(machine,
	event->fork.pid,
	event->fork.tid);

	dump_printf("(%d:%d):(%d:%d)\n", event->fork.pid, event->fork.tid,
	event->fork.ppid, event->fork.ptid);

	if (thread) {
	rb_erase(&thread->rb_node, &machine->threads);
	machine->last_match = NULL;
	thread__delete(thread);
	}

	return 0;
	}

	struct perf_tool build_id__mark_dso_hit_ops = {
	.sample = build_id__mark_dso_hit,
	.mmap = perf_event__process_mmap,
	.mmap2 = perf_event__process_mmap2,
	.fork = perf_event__process_fork,
	.exit = perf_event__exit_del_thread,
	.attr = perf_event__process_attr,
	.build_id = perf_event__process_build_id,
	};

	int build_id__sprintf(const u8 build_id, int len, char bf)
	{
	char *bid = bf;
	const u8 *raw = build_id;
	int i;

	for (i = 0; i < len; ++i) {
	sprintf(bid, "%02x", *raw);
	++raw;
	bid += 2;
	}

	return raw - build_id;
	}

	char dso__build_id_filename(const struct dso dso, char *bf, size_t size)
	{
	char build_id_hex[BUILD_ID_SIZE * 2 + 1];

	if (!dso->has_build_id)
	return NULL;

	build_id__sprintf(dso->build_id, sizeof(dso->build_id), build_id_hex);
	if (bf == NULL) {
	if (asprintf(&bf, "%s/.build-id/%.2s/%s", buildid_dir,
	build_id_hex, build_id_hex + 2) < 0)
	return NULL;
	} else
	snprintf(bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
	build_id_hex, build_id_hex + 2);
	return bf;
	}

	#define dsos__for_each_with_build_id(pos, head) \
	list_for_each_entry(pos, head, node) \
	if (!pos->has_build_id) \
	continue; \
	else

	static int write_buildid(const char name, size_t name_len, u8 build_id,
	pid_t pid, u16 misc, int fd)
	{
	int err;
	struct build_id_event b;
	size_t len;

	len = name_len + 1;
	len = PERF_ALIGN(len, NAME_ALIGN);

	memset(&b, 0, sizeof(b));
	memcpy(&b.build_id, build_id, BUILD_ID_SIZE);
	b.pid = pid;
	b.header.misc = misc;
	b.header.size = sizeof(b) + len;

	err = writen(fd, &b, sizeof(b));
	if (err < 0)
	return err;

	return write_padded(fd, name, name_len + 1, len);
	}

	static int __dsos__write_buildid_table(struct list_head *head,
	struct machine *machine,
	pid_t pid, u16 misc, int fd)
	{
	char nm[PATH_MAX];
	struct dso *pos;

	dsos__for_each_with_build_id(pos, head) {
	int err;
	const char *name;
	size_t name_len;

	if (!pos->hit)
	continue;

	if (dso__is_vdso(pos)) {
	name = pos->short_name;
	name_len = pos->short_name_len + 1;
	} else if (dso__is_kcore(pos)) {
	machine__mmap_name(machine, nm, sizeof(nm));
	name = nm;
	name_len = strlen(nm) + 1;
	} else {
	name = pos->long_name;
	name_len = pos->long_name_len + 1;
	}

	err = write_buildid(name, name_len, pos->build_id,
	pid, misc, fd);
	if (err)
	return err;
	}

	return 0;
	}

	static int machine__write_buildid_table(struct machine *machine, int fd)
	{
	int err;
	u16 kmisc = PERF_RECORD_MISC_KERNEL,
	umisc = PERF_RECORD_MISC_USER;

	if (!machine__is_host(machine)) {
	kmisc = PERF_RECORD_MISC_GUEST_KERNEL;
	umisc = PERF_RECORD_MISC_GUEST_USER;
	}

	err = __dsos__write_buildid_table(&machine->kernel_dsos.head, machine,
	machine->pid, kmisc, fd);
	if (err == 0)
	err = __dsos__write_buildid_table(&machine->user_dsos.head,
	machine, machine->pid, umisc,
	fd);
	return err;
	}

	int perf_session__write_buildid_table(struct perf_session *session, int fd)
	{
	struct rb_node *nd;
	int err = machine__write_buildid_table(&session->machines.host, fd);

	if (err)
	return err;

	for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
	struct machine *pos = rb_entry(nd, struct machine, rb_node);
	err = machine__write_buildid_table(pos, fd);
	if (err)
	break;
	}
	return err;
	}

	static int __dsos__hit_all(struct list_head *head)
	{
	struct dso *pos;

	list_for_each_entry(pos, head, node)
	pos->hit = true;

	return 0;
	}

	static int machine__hit_all_dsos(struct machine *machine)
	{
	int err;

	err = __dsos__hit_all(&machine->kernel_dsos.head);
	if (err)
	return err;

	return __dsos__hit_all(&machine->user_dsos.head);
	}

	int dsos__hit_all(struct perf_session *session)
	{
	struct rb_node *nd;
	int err;

	err = machine__hit_all_dsos(&session->machines.host);
	if (err)
	return err;

	for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
	struct machine *pos = rb_entry(nd, struct machine, rb_node);

	err = machine__hit_all_dsos(pos);
	if (err)
	return err;
	}

	return 0;
	}

	void disable_buildid_cache(void)
	{
	no_buildid_cache = true;
	}

	int build_id_cache__add_s(const char sbuild_id, const char debugdir,
	const char *name, bool is_kallsyms, bool is_vdso)
	{
	const size_t size = PATH_MAX;
	char realname, filename = zalloc(size),
	linkname = zalloc(size), targetname;
	int len, err = -1;
	bool slash = is_kallsyms \|\| is_vdso;

	if (is_kallsyms) {
	if (symbol_conf.kptr_restrict) {
	pr_debug("Not caching a kptr_restrict'ed /proc/kallsyms\n");
	err = 0;
	goto out_free;
	}
	realname = (char *) name;
	} else
	realname = realpath(name, NULL);

	if (realname == NULL \|\| filename == NULL \|\| linkname == NULL)
	goto out_free;

	len = scnprintf(filename, size, "%s%s%s",
	debugdir, slash ? "/" : "",
	is_vdso ? DSO__NAME_VDSO : realname);
	if (mkdir_p(filename, 0755))
	goto out_free;

	snprintf(filename + len, size - len, "/%s", sbuild_id);

	if (access(filename, F_OK)) {
	if (is_kallsyms) {
	if (copyfile("/proc/kallsyms", filename))
	goto out_free;
	} else if (link(realname, filename) && copyfile(name, filename))
	goto out_free;
	}

	len = scnprintf(linkname, size, "%s/.build-id/%.2s",
	debugdir, sbuild_id);

	if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
	goto out_free;

	snprintf(linkname + len, size - len, "/%s", sbuild_id + 2);
	targetname = filename + strlen(debugdir) - 5;
	memcpy(targetname, "../..", 5);

	if (symlink(targetname, linkname) == 0)
	err = 0;
	out_free:
	if (!is_kallsyms)
	free(realname);
	free(filename);
	free(linkname);
	return err;
	}

	static int build_id_cache__add_b(const u8 *build_id, size_t build_id_size,
	const char name, const char debugdir,
	bool is_kallsyms, bool is_vdso)
	{
	char sbuild_id[BUILD_ID_SIZE * 2 + 1];

	build_id__sprintf(build_id, build_id_size, sbuild_id);

	return build_id_cache__add_s(sbuild_id, debugdir, name,
	is_kallsyms, is_vdso);
	}

	int build_id_cache__remove_s(const char sbuild_id, const char debugdir)
	{
	const size_t size = PATH_MAX;
	char *filename = zalloc(size),
	*linkname = zalloc(size);
	int err = -1;

	if (filename == NULL \|\| linkname == NULL)
	goto out_free;

	snprintf(linkname, size, "%s/.build-id/%.2s/%s",
	debugdir, sbuild_id, sbuild_id + 2);

	if (access(linkname, F_OK))
	goto out_free;

	if (readlink(linkname, filename, size - 1) < 0)
	goto out_free;

	if (unlink(linkname))
	goto out_free;

	/*
	* Since the link is relative, we must make it absolute:
	*/
	snprintf(linkname, size, "%s/.build-id/%.2s/%s",
	debugdir, sbuild_id, filename);

	if (unlink(linkname))
	goto out_free;

	err = 0;
	out_free:
	free(filename);
	free(linkname);
	return err;
	}

	static int dso__cache_build_id(struct dso dso, struct machine machine,
	const char *debugdir)
	{
	bool is_kallsyms = dso->kernel && dso->long_name[0] != '/';
	bool is_vdso = dso__is_vdso(dso);
	const char *name = dso->long_name;
	char nm[PATH_MAX];

	if (dso__is_kcore(dso)) {
	is_kallsyms = true;
	machine__mmap_name(machine, nm, sizeof(nm));
	name = nm;
	}
	return build_id_cache__add_b(dso->build_id, sizeof(dso->build_id), name,
	debugdir, is_kallsyms, is_vdso);
	}

	static int __dsos__cache_build_ids(struct list_head *head,
	struct machine machine, const char debugdir)
	{
	struct dso *pos;
	int err = 0;

	dsos__for_each_with_build_id(pos, head)
	if (dso__cache_build_id(pos, machine, debugdir))
	err = -1;

	return err;
	}

	static int machine__cache_build_ids(struct machine machine, const char debugdir)
	{
	int ret = __dsos__cache_build_ids(&machine->kernel_dsos.head, machine,
	debugdir);
	ret \|= __dsos__cache_build_ids(&machine->user_dsos.head, machine,
	debugdir);
	return ret;
	}

	int perf_session__cache_build_ids(struct perf_session *session)
	{
	struct rb_node *nd;
	int ret;

	if (no_buildid_cache)
	return 0;

	if (mkdir(buildid_dir, 0755) != 0 && errno != EEXIST)
	return -1;

	ret = machine__cache_build_ids(&session->machines.host, buildid_dir);

	for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
	struct machine *pos = rb_entry(nd, struct machine, rb_node);
	ret \|= machine__cache_build_ids(pos, buildid_dir);
	}
	return ret ? -1 : 0;
	}

	static bool machine__read_build_ids(struct machine *machine, bool with_hits)
	{
	bool ret;

	ret = __dsos__read_build_ids(&machine->kernel_dsos.head, with_hits);
	ret \|= __dsos__read_build_ids(&machine->user_dsos.head, with_hits);
	return ret;
	}

	bool perf_session__read_build_ids(struct perf_session *session, bool with_hits)
	{
	struct rb_node *nd;
	bool ret = machine__read_build_ids(&session->machines.host, with_hits);

	for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
	struct machine *pos = rb_entry(nd, struct machine, rb_node);
	ret \|= machine__read_build_ids(pos, with_hits);
	}

	return ret;
	}