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Commit 259032bf authored by Sonny Rao's avatar Sonny Rao Committed by Steven Rostedt
Browse files

perf: Robustify proc and debugfs file recording 



While attempting to create a timechart of boot up I found perf didn't
tolerate modules being loaded/unloaded.  This patch fixes this by
reading the file once and then writing the size read at the correct
point in the file.  It also simplifies the code somewhat.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: default avatarSonny Rao <sonnyrao@chromium.org>
Signed-off-by: default avatarMichael Neuling <mikey@neuling.org>
Link: http://lkml.kernel.org/r/10011.1310614483@neuling.org


Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 6331c28c

tools/perf/util/trace-event-info.c

+29 −91
Original line number Diff line number Diff line
@@ -183,106 +183,59 @@ int bigendian(void) 
	return *ptr == 0x01020304;

}



static unsigned long long copy_file_fd(int fd)

/* unfortunately, you can not stat debugfs or proc files for size */

static void record_file(const char *file, size_t hdr_sz)

{

	unsigned long long size = 0;

	char buf[BUFSIZ];

	int r;



	do {

		r = read(fd, buf, BUFSIZ);

		if (r > 0) {

			size += r;

			write_or_die(buf, r);

		}

	} while (r > 0);



	return size;

}



static unsigned long long copy_file(const char *file)

{

	unsigned long long size = 0;

	int fd;

	char buf[BUFSIZ], *sizep;

	off_t hdr_pos = lseek(output_fd, 0, SEEK_CUR);

	int r, fd;



	fd = open(file, O_RDONLY);

	if (fd < 0)

		die("Can't read '%s'", file);

	size = copy_file_fd(fd);

	close(fd);



	return size;

}



static unsigned long get_size_fd(int fd)

{

	unsigned long long size = 0;

	char buf[BUFSIZ];

	int r;

	/* put in zeros for file size, then fill true size later */

	write_or_die(&size, hdr_sz);



	do {

		r = read(fd, buf, BUFSIZ);

		if (r > 0)

		if (r > 0) {

			size += r;

	} while (r > 0);



	lseek(fd, 0, SEEK_SET);



	return size;

			write_or_die(buf, r);

		}



static unsigned long get_size(const char *file)

{

	unsigned long long size = 0;

	int fd;



	fd = open(file, O_RDONLY);

	if (fd < 0)

		die("Can't read '%s'", file);

	size = get_size_fd(fd);

	} while (r > 0);

	close(fd);



	return size;

	/* ugh, handle big-endian hdr_size == 4 */

	sizep = (char*)&size;

	if (bigendian())

		sizep += sizeof(u64) - hdr_sz;



	if (pwrite(output_fd, sizep, hdr_sz, hdr_pos) < 0)

		die("writing to %s", output_file);

}



static void read_header_files(void)

{

	unsigned long long size, check_size;

	char *path;

	int fd;

	struct stat st;



	path = get_tracing_file("events/header_page");

	fd = open(path, O_RDONLY);

	if (fd < 0)

	if (stat(path, &st) < 0)

		die("can't read '%s'", path);



	/* unfortunately, you can not stat debugfs files for size */

	size = get_size_fd(fd);



	write_or_die("header_page", 12);

	write_or_die(&size, 8);

	check_size = copy_file_fd(fd);

	close(fd);



	if (size != check_size)

		die("wrong size for '%s' size=%lld read=%lld",

		    path, size, check_size);

	record_file(path, 8);

	put_tracing_file(path);



	path = get_tracing_file("events/header_event");

	fd = open(path, O_RDONLY);

	if (fd < 0)

	if (stat(path, &st) < 0)

		die("can't read '%s'", path);



	size = get_size_fd(fd);



	write_or_die("header_event", 13);

	write_or_die(&size, 8);

	check_size = copy_file_fd(fd);

	if (size != check_size)

		die("wrong size for '%s'", path);

	record_file(path, 8);

	put_tracing_file(path);

	close(fd);

}



static bool name_in_tp_list(char *sys, struct tracepoint_path *tps)
@@ -298,7 +251,6 @@ static bool name_in_tp_list(char *sys, struct tracepoint_path *tps) 


static void copy_event_system(const char *sys, struct tracepoint_path *tps)

{

	unsigned long long size, check_size;

	struct dirent *dent;

	struct stat st;

	char *format;
@@ -338,14 +290,8 @@ static void copy_event_system(const char *sys, struct tracepoint_path *tps) 
		sprintf(format, "%s/%s/format", sys, dent->d_name);

		ret = stat(format, &st);



		if (ret >= 0) {

			/* unfortunately, you can not stat debugfs files for size */

			size = get_size(format);

			write_or_die(&size, 8);

			check_size = copy_file(format);

			if (size != check_size)

				die("error in size of file '%s'", format);

		}

		if (ret >= 0)

			record_file(format, 8);



		free(format);

	}
@@ -426,7 +372,7 @@ static void read_event_files(struct tracepoint_path *tps) 


static void read_proc_kallsyms(void)

{

	unsigned int size, check_size;

	unsigned int size;

	const char *path = "/proc/kallsyms";

	struct stat st;

	int ret;
@@ -438,17 +384,12 @@ static void read_proc_kallsyms(void) 
		write_or_die(&size, 4);

		return;

	}

	size = get_size(path);

	write_or_die(&size, 4);

	check_size = copy_file(path);

	if (size != check_size)

		die("error in size of file '%s'", path);



	record_file(path, 4);

}



static void read_ftrace_printk(void)

{

	unsigned int size, check_size;

	unsigned int size;

	char *path;

	struct stat st;

	int ret;
@@ -461,11 +402,8 @@ static void read_ftrace_printk(void) 
		write_or_die(&size, 4);

		goto out;

	}

	size = get_size(path);

	write_or_die(&size, 4);

	check_size = copy_file(path);

	if (size != check_size)

		die("error in size of file '%s'", path);

	record_file(path, 4);



out:

	put_tracing_file(path);

}