perf record: auto detect when stdout is a pipe

This patch gives the ability to 'perf record' to detect when its stdout
has been redirected to a pipe. There's now no more need to add '-o -'
switch in this case.

However '-o <path>' option has always precedence, that is if specified
and stdout has been connected via a pipe then the output will go into
the specified output.

LKML-Reference: <m3ipxo966i.fsf@gmail.com>
Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Franck Bui-Huu 2011-01-16 17:14:45 +01:00 committed by Arnaldo Carvalho de Melo
parent e80711ca85
commit d7065adb9b

View File

@ -48,7 +48,7 @@ static unsigned int user_freq = UINT_MAX;
static int freq = 1000;
static int output;
static int pipe_output = 0;
static const char *output_name = "perf.data";
static const char *output_name = NULL;
static int group = 0;
static int realtime_prio = 0;
static bool nodelay = false;
@ -497,18 +497,26 @@ static int __cmd_record(int argc, const char **argv)
exit(-1);
}
if (!strcmp(output_name, "-"))
pipe_output = 1;
else if (!stat(output_name, &st) && st.st_size) {
if (write_mode == WRITE_FORCE) {
char oldname[PATH_MAX];
snprintf(oldname, sizeof(oldname), "%s.old",
output_name);
unlink(oldname);
rename(output_name, oldname);
if (!output_name) {
if (!fstat(STDOUT_FILENO, &st) && S_ISFIFO(st.st_mode))
pipe_output = 1;
else
output_name = "perf.data";
}
if (output_name) {
if (!strcmp(output_name, "-"))
pipe_output = 1;
else if (!stat(output_name, &st) && st.st_size) {
if (write_mode == WRITE_FORCE) {
char oldname[PATH_MAX];
snprintf(oldname, sizeof(oldname), "%s.old",
output_name);
unlink(oldname);
rename(output_name, oldname);
}
} else if (write_mode == WRITE_APPEND) {
write_mode = WRITE_FORCE;
}
} else if (write_mode == WRITE_APPEND) {
write_mode = WRITE_FORCE;
}
flags = O_CREAT|O_RDWR;