tools/perf/util/trace-event-info.c - third_party/linux - Git at Google

 /*
  * Copyright (C) 2008,2009, Steven Rostedt <srostedt@redhat.com>
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; version 2 of the License (not later!)
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  */
 #include "util.h"
 #include <dirent.h>
 #include <mntent.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <stdarg.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/wait.h>
 #include <pthread.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <errno.h>
 #include <stdbool.h>
 #include <linux/list.h>
 #include <linux/kernel.h>

 #include "../perf.h"
 #include "trace-event.h"
 #include <api/fs/tracing_path.h>
 #include "evsel.h"
 #include "debug.h"

 #define VERSION "0.5"

 static int output_fd;


 int bigendian(void)
 {
 	unsigned char str[] = { 0x1, 0x2, 0x3, 0x4, 0x0, 0x0, 0x0, 0x0};
 	unsigned int *ptr;

 	ptr = (unsigned int *)(void *)str;
 	return *ptr == 0x01020304;
 }

 /* unfortunately, you can not stat debugfs or proc files for size */
 static int record_file(const char *file, ssize_t hdr_sz)
 {
 	unsigned long long size = 0;
 	char buf[BUFSIZ], *sizep;
 	off_t hdr_pos = lseek(output_fd, 0, SEEK_CUR);
 	int r, fd;
 	int err = -EIO;

 	fd = open(file, O_RDONLY);
 	if (fd < 0) {
 		pr_debug("Can't read '%s'", file);
 		return -errno;
 	}

 	/* put in zeros for file size, then fill true size later */
 	if (hdr_sz) {
 		if (write(output_fd, &size, hdr_sz) != hdr_sz)
 			goto out;
 	}

 	do {
 		r = read(fd, buf, BUFSIZ);
 		if (r > 0) {
 			size += r;
 			if (write(output_fd, buf, r) != r)
 				goto out;
 		}
 	} while (r > 0);

 	/* ugh, handle big-endian hdr_size == 4 */
 	sizep = (char*)&size;
 	if (bigendian())
 		sizep += sizeof(u64) - hdr_sz;

 	if (hdr_sz && pwrite(output_fd, sizep, hdr_sz, hdr_pos) < 0) {
 		pr_debug("writing file size failed\n");
 		goto out;
 	}

 	err = 0;
 out:
 	close(fd);
 	return err;
 }

 static int record_header_files(void)
 {
 	char *path;
 	struct stat st;
 	int err = -EIO;

 	path = get_tracing_file("events/header_page");
 	if (!path) {
 		pr_debug("can't get tracing/events/header_page");
 		return -ENOMEM;
 	}

 	if (stat(path, &st) < 0) {
 		pr_debug("can't read '%s'", path);
 		goto out;
 	}

 	if (write(output_fd, "header_page", 12) != 12) {
 		pr_debug("can't write header_page\n");
 		goto out;
 	}

 	if (record_file(path, 8) < 0) {
 		pr_debug("can't record header_page file\n");
 		goto out;
 	}

 	put_tracing_file(path);

 	path = get_tracing_file("events/header_event");
 	if (!path) {
 		pr_debug("can't get tracing/events/header_event");
 		err = -ENOMEM;
 		goto out;
 	}

 	if (stat(path, &st) < 0) {
 		pr_debug("can't read '%s'", path);
 		goto out;
 	}

 	if (write(output_fd, "header_event", 13) != 13) {
 		pr_debug("can't write header_event\n");
 		goto out;
 	}

 	if (record_file(path, 8) < 0) {
 		pr_debug("can't record header_event file\n");
 		goto out;
 	}

 	err = 0;
 out:
 	put_tracing_file(path);
 	return err;
 }

 static bool name_in_tp_list(char *sys, struct tracepoint_path *tps)
 {
 	while (tps) {
 		if (!strcmp(sys, tps->name))
 			return true;
 		tps = tps->next;
 	}

 	return false;
 }

 static int copy_event_system(const char *sys, struct tracepoint_path *tps)
 {
 	struct dirent *dent;
 	struct stat st;
 	char *format;
 	DIR *dir;
 	int count = 0;
 	int ret;
 	int err;

 	dir = opendir(sys);
 	if (!dir) {
 		pr_debug("can't read directory '%s'", sys);
 		return -errno;
 	}

 	while ((dent = readdir(dir))) {
 		if (dent->d_type != DT_DIR ||
 		    strcmp(dent->d_name, ".") == 0 ||
 		    strcmp(dent->d_name, "..") == 0 ||
 		    !name_in_tp_list(dent->d_name, tps))
 			continue;
 		if (asprintf(&format, "%s/%s/format", sys, dent->d_name) < 0) {
 			err = -ENOMEM;
 			goto out;
 		}
 		ret = stat(format, &st);
 		free(format);
 		if (ret < 0)
 			continue;
 		count++;
 	}

 	if (write(output_fd, &count, 4) != 4) {
 		err = -EIO;
 		pr_debug("can't write count\n");
 		goto out;
 	}

 	rewinddir(dir);
 	while ((dent = readdir(dir))) {
 		if (dent->d_type != DT_DIR ||
 		    strcmp(dent->d_name, ".") == 0 ||
 		    strcmp(dent->d_name, "..") == 0 ||
 		    !name_in_tp_list(dent->d_name, tps))
 			continue;
 		if (asprintf(&format, "%s/%s/format", sys, dent->d_name) < 0) {
 			err = -ENOMEM;
 			goto out;
 		}
 		ret = stat(format, &st);

 		if (ret >= 0) {
 			err = record_file(format, 8);
 			if (err) {
 				free(format);
 				goto out;
 			}
 		}
 		free(format);
 	}
 	err = 0;
 out:
 	closedir(dir);
 	return err;
 }

 static int record_ftrace_files(struct tracepoint_path *tps)
 {
 	char *path;
 	int ret;

 	path = get_tracing_file("events/ftrace");
 	if (!path) {
 		pr_debug("can't get tracing/events/ftrace");
 		return -ENOMEM;
 	}

 	ret = copy_event_system(path, tps);

 	put_tracing_file(path);

 	return ret;
 }

 static bool system_in_tp_list(char *sys, struct tracepoint_path *tps)
 {
 	while (tps) {
 		if (!strcmp(sys, tps->system))
 			return true;
 		tps = tps->next;
 	}

 	return false;
 }

 static int record_event_files(struct tracepoint_path *tps)
 {
 	struct dirent *dent;
 	struct stat st;
 	char *path;
 	char *sys;
 	DIR *dir;
 	int count = 0;
 	int ret;
 	int err;

 	path = get_tracing_file("events");
 	if (!path) {
 		pr_debug("can't get tracing/events");
 		return -ENOMEM;
 	}

 	dir = opendir(path);
 	if (!dir) {
 		err = -errno;
 		pr_debug("can't read directory '%s'", path);
 		goto out;
 	}

 	while ((dent = readdir(dir))) {
 		if (dent->d_type != DT_DIR ||
 		    strcmp(dent->d_name, ".") == 0 ||
 		    strcmp(dent->d_name, "..") == 0 ||
 		    strcmp(dent->d_name, "ftrace") == 0 ||
 		    !system_in_tp_list(dent->d_name, tps))
 			continue;
 		count++;
 	}

 	if (write(output_fd, &count, 4) != 4) {
 		err = -EIO;
 		pr_debug("can't write count\n");
 		goto out;
 	}

 	rewinddir(dir);
 	while ((dent = readdir(dir))) {
 		if (dent->d_type != DT_DIR ||
 		    strcmp(dent->d_name, ".") == 0 ||
 		    strcmp(dent->d_name, "..") == 0 ||
 		    strcmp(dent->d_name, "ftrace") == 0 ||
 		    !system_in_tp_list(dent->d_name, tps))
 			continue;
 		if (asprintf(&sys, "%s/%s", path, dent->d_name) < 0) {
 			err = -ENOMEM;
 			goto out;
 		}
 		ret = stat(sys, &st);
 		if (ret >= 0) {
 			ssize_t size = strlen(dent->d_name) + 1;

 			if (write(output_fd, dent->d_name, size) != size ||
 			    copy_event_system(sys, tps) < 0) {
 				err = -EIO;
 				free(sys);
 				goto out;
 			}
 		}
 		free(sys);
 	}
 	err = 0;
 out:
 	closedir(dir);
 	put_tracing_file(path);

 	return err;
 }

 static int record_proc_kallsyms(void)
 {
 	unsigned long long size = 0;
 	/*
 	 * Just to keep older perf.data file parsers happy, record a zero
 	 * sized kallsyms file, i.e. do the same thing that was done when
 	 * /proc/kallsyms (or something specified via --kallsyms, in a
 	 * different path) couldn't be read.
 	 */
 	return write(output_fd, &size, 4) != 4 ? -EIO : 0;
 }

 static int record_ftrace_printk(void)
 {
 	unsigned int size;
 	char *path;
 	struct stat st;
 	int ret, err = 0;

 	path = get_tracing_file("printk_formats");
 	if (!path) {
 		pr_debug("can't get tracing/printk_formats");
 		return -ENOMEM;
 	}

 	ret = stat(path, &st);
 	if (ret < 0) {
 		/* not found */
 		size = 0;
 		if (write(output_fd, &size, 4) != 4)
 			err = -EIO;
 		goto out;
 	}
 	err = record_file(path, 4);

 out:
 	put_tracing_file(path);
 	return err;
 }

 static void
 put_tracepoints_path(struct tracepoint_path *tps)
 {
 	while (tps) {
 		struct tracepoint_path *t = tps;

 		tps = tps->next;
 		zfree(&t->name);
 		zfree(&t->system);
 		free(t);
 	}
 }

 static struct tracepoint_path *
 get_tracepoints_path(struct list_head *pattrs)
 {
 	struct tracepoint_path path, *ppath = &path;
 	struct perf_evsel *pos;
 	int nr_tracepoints = 0;

 	list_for_each_entry(pos, pattrs, node) {
 		if (pos->attr.type != PERF_TYPE_TRACEPOINT)
 			continue;
 		++nr_tracepoints;

 		if (pos->name) {
 			ppath->next = tracepoint_name_to_path(pos->name);
 			if (ppath->next)
 				goto next;

 			if (strchr(pos->name, ':') == NULL)
 				goto try_id;

 			goto error;
 		}

 try_id:
 		ppath->next = tracepoint_id_to_path(pos->attr.config);
 		if (!ppath->next) {
 error:
 			pr_debug("No memory to alloc tracepoints list\n");
 			put_tracepoints_path(&path);
 			return NULL;
 		}
 next:
 		ppath = ppath->next;
 	}

 	return nr_tracepoints > 0 ? path.next : NULL;
 }

 bool have_tracepoints(struct list_head *pattrs)
 {
 	struct perf_evsel *pos;

 	list_for_each_entry(pos, pattrs, node)
 		if (pos->attr.type == PERF_TYPE_TRACEPOINT)
 			return true;

 	return false;
 }

 static int tracing_data_header(void)
 {
 	char buf[20];
 	ssize_t size;

 	/* just guessing this is someone's birthday.. ;) */
 	buf[0] = 23;
 	buf[1] = 8;
 	buf[2] = 68;
 	memcpy(buf + 3, "tracing", 7);

 	if (write(output_fd, buf, 10) != 10)
 		return -1;

 	size = strlen(VERSION) + 1;
 	if (write(output_fd, VERSION, size) != size)
 		return -1;

 	/* save endian */
 	if (bigendian())
 		buf[0] = 1;
 	else
 		buf[0] = 0;

 	if (write(output_fd, buf, 1) != 1)
 		return -1;

 	/* save size of long */
 	buf[0] = sizeof(long);
 	if (write(output_fd, buf, 1) != 1)
 		return -1;

 	/* save page_size */
 	if (write(output_fd, &page_size, 4) != 4)
 		return -1;

 	return 0;
 }

 struct tracing_data *tracing_data_get(struct list_head *pattrs,
 				      int fd, bool temp)
 {
 	struct tracepoint_path *tps;
 	struct tracing_data *tdata;
 	int err;

 	output_fd = fd;

 	tps = get_tracepoints_path(pattrs);
 	if (!tps)
 		return NULL;

 	tdata = malloc(sizeof(*tdata));
 	if (!tdata)
 		return NULL;

 	tdata->temp = temp;
 	tdata->size = 0;

 	if (temp) {
 		int temp_fd;

 		snprintf(tdata->temp_file, sizeof(tdata->temp_file),
 			 "/tmp/perf-XXXXXX");
 		if (!mkstemp(tdata->temp_file)) {
 			pr_debug("Can't make temp file");
 			free(tdata);
 			return NULL;
 		}

 		temp_fd = open(tdata->temp_file, O_RDWR);
 		if (temp_fd < 0) {
 			pr_debug("Can't read '%s'", tdata->temp_file);
 			free(tdata);
 			return NULL;
 		}

 		/*
 		 * Set the temp file the default output, so all the
 		 * tracing data are stored into it.
 		 */
 		output_fd = temp_fd;
 	}

 	err = tracing_data_header();
 	if (err)
 		goto out;
 	err = record_header_files();
 	if (err)
 		goto out;
 	err = record_ftrace_files(tps);
 	if (err)
 		goto out;
 	err = record_event_files(tps);
 	if (err)
 		goto out;
 	err = record_proc_kallsyms();
 	if (err)
 		goto out;
 	err = record_ftrace_printk();

 out:
 	/*
 	 * All tracing data are stored by now, we can restore
 	 * the default output file in case we used temp file.
 	 */
 	if (temp) {
 		tdata->size = lseek(output_fd, 0, SEEK_CUR);
 		close(output_fd);
 		output_fd = fd;
 	}

 	if (err)
 		zfree(&tdata);

 	put_tracepoints_path(tps);
 	return tdata;
 }

 int tracing_data_put(struct tracing_data *tdata)
 {
 	int err = 0;

 	if (tdata->temp) {
 		err = record_file(tdata->temp_file, 0);
 		unlink(tdata->temp_file);
 	}

 	free(tdata);
 	return err;
 }

 int read_tracing_data(int fd, struct list_head *pattrs)
 {
 	int err;
 	struct tracing_data *tdata;

 	/*
 	 * We work over the real file, so we can write data
 	 * directly, no temp file is needed.
 	 */
 	tdata = tracing_data_get(pattrs, fd, false);
 	if (!tdata)
 		return -ENOMEM;

 	err = tracing_data_put(tdata);
 	return err;
 }
	/*
	* Copyright (C) 2008,2009, Steven Rostedt <srostedt@redhat.com>
	*
	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; version 2 of the License (not later!)
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*
	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	*/
	#include "util.h"
	#include <dirent.h>
	#include <mntent.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <stdarg.h>
	#include <sys/types.h>
	#include <sys/stat.h>
	#include <sys/wait.h>
	#include <pthread.h>
	#include <fcntl.h>
	#include <unistd.h>
	#include <errno.h>
	#include <stdbool.h>
	#include <linux/list.h>
	#include <linux/kernel.h>

	#include "../perf.h"
	#include "trace-event.h"
	#include <api/fs/tracing_path.h>
	#include "evsel.h"
	#include "debug.h"

	#define VERSION "0.5"

	static int output_fd;


	int bigendian(void)
	{
	unsigned char str[] = { 0x1, 0x2, 0x3, 0x4, 0x0, 0x0, 0x0, 0x0};
	unsigned int *ptr;

	ptr = (unsigned int )(void )str;
	return *ptr == 0x01020304;
	}

	/* unfortunately, you can not stat debugfs or proc files for size */
	static int record_file(const char *file, ssize_t hdr_sz)
	{
	unsigned long long size = 0;
	char buf[BUFSIZ], *sizep;
	off_t hdr_pos = lseek(output_fd, 0, SEEK_CUR);
	int r, fd;
	int err = -EIO;

	fd = open(file, O_RDONLY);
	if (fd < 0) {
	pr_debug("Can't read '%s'", file);
	return -errno;
	}

	/* put in zeros for file size, then fill true size later */
	if (hdr_sz) {
	if (write(output_fd, &size, hdr_sz) != hdr_sz)
	goto out;
	}

	do {
	r = read(fd, buf, BUFSIZ);
	if (r > 0) {
	size += r;
	if (write(output_fd, buf, r) != r)
	goto out;
	}
	} while (r > 0);

	/* ugh, handle big-endian hdr_size == 4 */
	sizep = (char*)&size;
	if (bigendian())
	sizep += sizeof(u64) - hdr_sz;

	if (hdr_sz && pwrite(output_fd, sizep, hdr_sz, hdr_pos) < 0) {
	pr_debug("writing file size failed\n");
	goto out;
	}

	err = 0;
	out:
	close(fd);
	return err;
	}

	static int record_header_files(void)
	{
	char *path;
	struct stat st;
	int err = -EIO;

	path = get_tracing_file("events/header_page");
	if (!path) {
	pr_debug("can't get tracing/events/header_page");
	return -ENOMEM;
	}

	if (stat(path, &st) < 0) {
	pr_debug("can't read '%s'", path);
	goto out;
	}

	if (write(output_fd, "header_page", 12) != 12) {
	pr_debug("can't write header_page\n");
	goto out;
	}

	if (record_file(path, 8) < 0) {
	pr_debug("can't record header_page file\n");
	goto out;
	}

	put_tracing_file(path);

	path = get_tracing_file("events/header_event");
	if (!path) {
	pr_debug("can't get tracing/events/header_event");
	err = -ENOMEM;
	goto out;
	}

	if (stat(path, &st) < 0) {
	pr_debug("can't read '%s'", path);
	goto out;
	}

	if (write(output_fd, "header_event", 13) != 13) {
	pr_debug("can't write header_event\n");
	goto out;
	}

	if (record_file(path, 8) < 0) {
	pr_debug("can't record header_event file\n");
	goto out;
	}

	err = 0;
	out:
	put_tracing_file(path);
	return err;
	}

	static bool name_in_tp_list(char sys, struct tracepoint_path tps)
	{
	while (tps) {
	if (!strcmp(sys, tps->name))
	return true;
	tps = tps->next;
	}

	return false;
	}

	static int copy_event_system(const char sys, struct tracepoint_path tps)
	{
	struct dirent *dent;
	struct stat st;
	char *format;
	DIR *dir;
	int count = 0;
	int ret;
	int err;

	dir = opendir(sys);
	if (!dir) {
	pr_debug("can't read directory '%s'", sys);
	return -errno;
	}

	while ((dent = readdir(dir))) {
	if (dent->d_type != DT_DIR \|\|
	strcmp(dent->d_name, ".") == 0 \|\|
	strcmp(dent->d_name, "..") == 0 \|\|
	!name_in_tp_list(dent->d_name, tps))
	continue;
	if (asprintf(&format, "%s/%s/format", sys, dent->d_name) < 0) {
	err = -ENOMEM;
	goto out;
	}
	ret = stat(format, &st);
	free(format);
	if (ret < 0)
	continue;
	count++;
	}

	if (write(output_fd, &count, 4) != 4) {
	err = -EIO;
	pr_debug("can't write count\n");
	goto out;
	}

	rewinddir(dir);
	while ((dent = readdir(dir))) {
	if (dent->d_type != DT_DIR \|\|
	strcmp(dent->d_name, ".") == 0 \|\|
	strcmp(dent->d_name, "..") == 0 \|\|
	!name_in_tp_list(dent->d_name, tps))
	continue;
	if (asprintf(&format, "%s/%s/format", sys, dent->d_name) < 0) {
	err = -ENOMEM;
	goto out;
	}
	ret = stat(format, &st);

	if (ret >= 0) {
	err = record_file(format, 8);
	if (err) {
	free(format);
	goto out;
	}
	}
	free(format);
	}
	err = 0;
	out:
	closedir(dir);
	return err;
	}

	static int record_ftrace_files(struct tracepoint_path *tps)
	{
	char *path;
	int ret;

	path = get_tracing_file("events/ftrace");
	if (!path) {
	pr_debug("can't get tracing/events/ftrace");
	return -ENOMEM;
	}

	ret = copy_event_system(path, tps);

	put_tracing_file(path);

	return ret;
	}

	static bool system_in_tp_list(char sys, struct tracepoint_path tps)
	{
	while (tps) {
	if (!strcmp(sys, tps->system))
	return true;
	tps = tps->next;
	}

	return false;
	}

	static int record_event_files(struct tracepoint_path *tps)
	{
	struct dirent *dent;
	struct stat st;
	char *path;
	char *sys;
	DIR *dir;
	int count = 0;
	int ret;
	int err;

	path = get_tracing_file("events");
	if (!path) {
	pr_debug("can't get tracing/events");
	return -ENOMEM;
	}

	dir = opendir(path);
	if (!dir) {
	err = -errno;
	pr_debug("can't read directory '%s'", path);
	goto out;
	}

	while ((dent = readdir(dir))) {
	if (dent->d_type != DT_DIR \|\|
	strcmp(dent->d_name, ".") == 0 \|\|
	strcmp(dent->d_name, "..") == 0 \|\|
	strcmp(dent->d_name, "ftrace") == 0 \|\|
	!system_in_tp_list(dent->d_name, tps))
	continue;
	count++;
	}

	if (write(output_fd, &count, 4) != 4) {
	err = -EIO;
	pr_debug("can't write count\n");
	goto out;
	}

	rewinddir(dir);
	while ((dent = readdir(dir))) {
	if (dent->d_type != DT_DIR \|\|
	strcmp(dent->d_name, ".") == 0 \|\|
	strcmp(dent->d_name, "..") == 0 \|\|
	strcmp(dent->d_name, "ftrace") == 0 \|\|
	!system_in_tp_list(dent->d_name, tps))
	continue;
	if (asprintf(&sys, "%s/%s", path, dent->d_name) < 0) {
	err = -ENOMEM;
	goto out;
	}
	ret = stat(sys, &st);
	if (ret >= 0) {
	ssize_t size = strlen(dent->d_name) + 1;

	if (write(output_fd, dent->d_name, size) != size \|\|
	copy_event_system(sys, tps) < 0) {
	err = -EIO;
	free(sys);
	goto out;
	}
	}
	free(sys);
	}
	err = 0;
	out:
	closedir(dir);
	put_tracing_file(path);

	return err;
	}

	static int record_proc_kallsyms(void)
	{
	unsigned long long size = 0;
	/*
	* Just to keep older perf.data file parsers happy, record a zero
	* sized kallsyms file, i.e. do the same thing that was done when
	* /proc/kallsyms (or something specified via --kallsyms, in a
	* different path) couldn't be read.
	*/
	return write(output_fd, &size, 4) != 4 ? -EIO : 0;
	}

	static int record_ftrace_printk(void)
	{
	unsigned int size;
	char *path;
	struct stat st;
	int ret, err = 0;

	path = get_tracing_file("printk_formats");
	if (!path) {
	pr_debug("can't get tracing/printk_formats");
	return -ENOMEM;
	}

	ret = stat(path, &st);
	if (ret < 0) {
	/* not found */
	size = 0;
	if (write(output_fd, &size, 4) != 4)
	err = -EIO;
	goto out;
	}
	err = record_file(path, 4);

	out:
	put_tracing_file(path);
	return err;
	}

	static void
	put_tracepoints_path(struct tracepoint_path *tps)
	{
	while (tps) {
	struct tracepoint_path *t = tps;

	tps = tps->next;
	zfree(&t->name);
	zfree(&t->system);
	free(t);
	}
	}

	static struct tracepoint_path *
	get_tracepoints_path(struct list_head *pattrs)
	{
	struct tracepoint_path path, *ppath = &path;
	struct perf_evsel *pos;
	int nr_tracepoints = 0;

	list_for_each_entry(pos, pattrs, node) {
	if (pos->attr.type != PERF_TYPE_TRACEPOINT)
	continue;
	++nr_tracepoints;

	if (pos->name) {
	ppath->next = tracepoint_name_to_path(pos->name);
	if (ppath->next)
	goto next;

	if (strchr(pos->name, ':') == NULL)
	goto try_id;

	goto error;
	}

	try_id:
	ppath->next = tracepoint_id_to_path(pos->attr.config);
	if (!ppath->next) {
	error:
	pr_debug("No memory to alloc tracepoints list\n");
	put_tracepoints_path(&path);
	return NULL;
	}
	next:
	ppath = ppath->next;
	}

	return nr_tracepoints > 0 ? path.next : NULL;
	}

	bool have_tracepoints(struct list_head *pattrs)
	{
	struct perf_evsel *pos;

	list_for_each_entry(pos, pattrs, node)
	if (pos->attr.type == PERF_TYPE_TRACEPOINT)
	return true;

	return false;
	}

	static int tracing_data_header(void)
	{
	char buf[20];
	ssize_t size;

	/* just guessing this is someone's birthday.. ;) */
	buf[0] = 23;
	buf[1] = 8;
	buf[2] = 68;
	memcpy(buf + 3, "tracing", 7);

	if (write(output_fd, buf, 10) != 10)
	return -1;

	size = strlen(VERSION) + 1;
	if (write(output_fd, VERSION, size) != size)
	return -1;

	/* save endian */
	if (bigendian())
	buf[0] = 1;
	else
	buf[0] = 0;

	if (write(output_fd, buf, 1) != 1)
	return -1;

	/* save size of long */
	buf[0] = sizeof(long);
	if (write(output_fd, buf, 1) != 1)
	return -1;

	/* save page_size */
	if (write(output_fd, &page_size, 4) != 4)
	return -1;

	return 0;
	}

	struct tracing_data tracing_data_get(struct list_head pattrs,
	int fd, bool temp)
	{
	struct tracepoint_path *tps;
	struct tracing_data *tdata;
	int err;

	output_fd = fd;

	tps = get_tracepoints_path(pattrs);
	if (!tps)
	return NULL;

	tdata = malloc(sizeof(*tdata));
	if (!tdata)
	return NULL;

	tdata->temp = temp;
	tdata->size = 0;

	if (temp) {
	int temp_fd;

	snprintf(tdata->temp_file, sizeof(tdata->temp_file),
	"/tmp/perf-XXXXXX");
	if (!mkstemp(tdata->temp_file)) {
	pr_debug("Can't make temp file");
	free(tdata);
	return NULL;
	}

	temp_fd = open(tdata->temp_file, O_RDWR);
	if (temp_fd < 0) {
	pr_debug("Can't read '%s'", tdata->temp_file);
	free(tdata);
	return NULL;
	}

	/*
	* Set the temp file the default output, so all the
	* tracing data are stored into it.
	*/
	output_fd = temp_fd;
	}

	err = tracing_data_header();
	if (err)
	goto out;
	err = record_header_files();
	if (err)
	goto out;
	err = record_ftrace_files(tps);
	if (err)
	goto out;
	err = record_event_files(tps);
	if (err)
	goto out;
	err = record_proc_kallsyms();
	if (err)
	goto out;
	err = record_ftrace_printk();

	out:
	/*
	* All tracing data are stored by now, we can restore
	* the default output file in case we used temp file.
	*/
	if (temp) {
	tdata->size = lseek(output_fd, 0, SEEK_CUR);
	close(output_fd);
	output_fd = fd;
	}

	if (err)
	zfree(&tdata);

	put_tracepoints_path(tps);
	return tdata;
	}

	int tracing_data_put(struct tracing_data *tdata)
	{
	int err = 0;

	if (tdata->temp) {
	err = record_file(tdata->temp_file, 0);
	unlink(tdata->temp_file);
	}

	free(tdata);
	return err;
	}

	int read_tracing_data(int fd, struct list_head *pattrs)
	{
	int err;
	struct tracing_data *tdata;

	/*
	* We work over the real file, so we can write data
	* directly, no temp file is needed.
	*/
	tdata = tracing_data_get(pattrs, fd, false);
	if (!tdata)
	return -ENOMEM;

	err = tracing_data_put(tdata);
	return err;
	}