Commit 88adb119 authored by Jiri Olsa's avatar Jiri Olsa Committed by Arnaldo Carvalho de Melo
Browse files

perf daemon: Add background support 



Add support to put the daemon process in the background.

It's now enabled by default and -f option is added to keep the daemon
process on the console for debugging.

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Budankov <abudankov@huawei.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lore.kernel.org/r/20210208200908.1019149-9-jolsa@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 3cda0625

tools/perf/Documentation/perf-daemon.txt

+4 −0
Original line number Diff line number Diff line
@@ -56,6 +56,10 @@ START COMMAND 
-------------

The start command creates the daemon process.



-f::

--foreground::

	Do not put the process in background.





CONFIG FILE

-----------

tools/perf/builtin-daemon.c

+62 −0
Original line number Diff line number Diff line
@@ -675,10 +675,61 @@ static int setup_config(struct daemon *daemon) 
	return daemon->config_real ? 0 : -1;

}



static int go_background(struct daemon *daemon)

{

	int pid, fd;



	pid = fork();

	if (pid < 0)

		return -1;



	if (pid > 0)

		return 1;



	if (setsid() < 0)

		return -1;



	umask(0);



	if (chdir(daemon->base)) {

		perror("failed: chdir");

		return -1;

	}



	fd = open("output", O_RDWR|O_CREAT|O_TRUNC, 0644);

	if (fd < 0) {

		perror("failed: open");

		return -1;

	}



	if (fcntl(fd, F_SETFD, FD_CLOEXEC)) {

		perror("failed: fcntl FD_CLOEXEC");

		close(fd);

		return -1;

	}



	close(0);

	dup2(fd, 1);

	dup2(fd, 2);

	close(fd);



	daemon->out = fdopen(1, "w");

	if (!daemon->out) {

		close(1);

		close(2);

		return -1;

	}



	setbuf(daemon->out, NULL);

	return 0;

}



static int __cmd_start(struct daemon *daemon, struct option parent_options[],

		       int argc, const char **argv)

{

	bool foreground = false;

	struct option start_options[] = {

		OPT_BOOLEAN('f', "foreground", &foreground, "stay on console"),

		OPT_PARENT(parent_options),

		OPT_END()

	};
@@ -699,6 +750,17 @@ static int __cmd_start(struct daemon *daemon, struct option parent_options[], 
	if (setup_server_config(daemon))

		return -1;



	if (!foreground) {

		err = go_background(daemon);

		if (err) {

			/* original process, exit normally */

			if (err == 1)

				err = 0;

			daemon__exit(daemon);

			return err;

		}

	}



	debug_set_file(daemon->out);

	debug_set_display_time(true);