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perf: Robustify proc and debugfs file recording
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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: Sonny Rao <sonnyrao@chromium.org>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Link: http://lkml.kernel.org/r/10011.1310614483@neuling.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Sonny Rao authored and Steven Rostedt committed Jul 14, 2011
1 parent 6331c28 commit 259032b
Showing 1 changed file with 29 additions and 91 deletions.
120 changes: 29 additions & 91 deletions tools/perf/util/trace-event-info.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
write_or_die(buf, r);
}
} while (r > 0);

lseek(fd, 0, SEEK_SET);

return size;
}

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);
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)
Expand All @@ -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;
Expand Down Expand Up @@ -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);
}
Expand Down Expand Up @@ -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;
Expand All @@ -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;
Expand All @@ -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);
}
Expand Down

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