path: root/tools/perf/util/build-id.c

// SPDX-License-Identifier: GPL-2.0
/*
 * 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" // lsdir(), mkdir_p(), rm_rf()
#include <dirent.h>
#include <errno.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include "util/copyfile.h"
#include "dso.h"
#include "build-id.h"
#include "event.h"
#include "namespaces.h"
#include "map.h"
#include "symbol.h"
#include "thread.h"
#include <linux/kernel.h>
#include "debug.h"
#include "session.h"
#include "tool.h"
#include "header.h"
#include "vdso.h"
#include "path.h"
#include "probe-file.h"
#include "strlist.h"

#ifdef HAVE_DEBUGINFOD_SUPPORT
#include <elfutils/debuginfod.h>
#endif

#include <linux/ctype.h>
#include <linux/zalloc.h>
#include <linux/string.h>
#include <asm/bug.h>

static bool no_buildid_cache;

int build_id__mark_dso_hit(const struct perf_tool *tool __maybe_unused,
			   union perf_event *event,
			   struct perf_sample *sample,
			   struct evsel *evsel __maybe_unused,
			   struct machine *machine)
{
	struct addr_location al;
	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;
	}

	addr_location__init(&al);
	if (thread__find_map(thread, sample->cpumode, sample->ip, &al))
		dso__set_hit(map__dso(al.map));

	addr_location__exit(&al);
	thread__put(thread);
	return 0;
}

int build_id__sprintf(const struct build_id *build_id, char *bf)
{
	char *bid = bf;
	const u8 *raw = build_id->data;
	size_t i;

	bf[0] = 0x0;

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

	return (bid - bf) + 1;
}

int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id)
{
	char notes[PATH_MAX];
	struct build_id bid;
	int ret;

	if (!root_dir)
		root_dir = "";

	scnprintf(notes, sizeof(notes), "%s/sys/kernel/notes", root_dir);

	ret = sysfs__read_build_id(notes, &bid);
	if (ret < 0)
		return ret;

	return build_id__sprintf(&bid, sbuild_id);
}

int filename__sprintf_build_id(const char *pathname, char *sbuild_id)
{
	struct build_id bid;
	int ret;

	ret = filename__read_build_id(pathname, &bid);
	if (ret < 0)
		return ret;

	return build_id__sprintf(&bid, sbuild_id);
}

/* asnprintf consolidates asprintf and snprintf */
static int asnprintf(char **strp, size_t size, const char *fmt, ...)
{
	va_list ap;
	int ret;

	if (!strp)
		return -EINVAL;

	va_start(ap, fmt);
	if (*strp)
		ret = vsnprintf(*strp, size, fmt, ap);
	else
		ret = vasprintf(strp, fmt, ap);
	va_end(ap);

	return ret;
}

char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
				    size_t size)
{
	bool retry_old = true;

	snprintf(bf, size, "%s/%s/%s/kallsyms",
		 buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
retry:
	if (!access(bf, F_OK))
		return bf;
	if (retry_old) {
		/* Try old style kallsyms cache */
		snprintf(bf, size, "%s/%s/%s",
			 buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
		retry_old = false;
		goto retry;
	}

	return NULL;
}

char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size)
{
	char *tmp = bf;
	int ret = asnprintf(&bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
			    sbuild_id, sbuild_id + 2);
	if (ret < 0 || (tmp && size < (unsigned int)ret))
		return NULL;
	return bf;
}

/* The caller is responsible to free the returned buffer. */
char *build_id_cache__origname(const char *sbuild_id)
{
	char *linkname;
	char buf[PATH_MAX];
	char *ret = NULL, *p;
	size_t offs = 5;	/* == strlen("../..") */
	ssize_t len;

	linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
	if (!linkname)
		return NULL;

	len = readlink(linkname, buf, sizeof(buf) - 1);
	if (len <= 0)
		goto out;
	buf[len] = '\0';

	/* The link should be "../..<origpath>/<sbuild_id>" */
	p = strrchr(buf, '/');	/* Cut off the "/<sbuild_id>" */
	if (p && (p > buf + offs)) {
		*p = '\0';
		if (buf[offs + 1] == '[')
			offs++;	/*
				 * This is a DSO name, like [kernel.kallsyms].
				 * Skip the first '/', since this is not the
				 * cache of a regular file.
				 */
		ret = strdup(buf + offs);	/* Skip "../..[/]" */
	}
out:
	free(linkname);
	return ret;
}

/* Check if the given build_id cache is valid on current running system */
static bool build_id_cache__valid_id(char *sbuild_id)
{
	char real_sbuild_id[SBUILD_ID_SIZE] = "";
	char *pathname;
	int ret = 0;
	bool result = false;

	pathname = build_id_cache__origname(sbuild_id);
	if (!