From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Wed, 27 Nov 2019 05:32:24 +0000 (-0500)
Subject: relayd: track stdio output file descriptors
X-Git-Tag: v2.12.0-rc1~54
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=9c256b0146b021962e93fda7400c61ceb2b0d45f;p=lttng-tools.git

relayd: track stdio output file descriptors

Track the stdout and stderr file descriptors through the fd
tracker. These file descriptors are considered unsuspendable
since they can't be re-opened.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: Ibd80fb1ba1b21ee152bae6047a5dd176d1d2c051
---

diff --git a/src/bin/lttng-relayd/main.c b/src/bin/lttng-relayd/main.c
index 6318f8308..16bfccbfa 100644
--- a/src/bin/lttng-relayd/main.c
+++ b/src/bin/lttng-relayd/main.c
@@ -677,6 +677,11 @@ static void relayd_cleanup(void)
 				sessiond_trace_chunk_registry);
 	}
 	if (the_fd_tracker) {
+		untrack_stdio();
+		/*
+		 * fd_tracker_destroy() will log the contents of the fd-tracker
+		 * if a leak is detected.
+		 */
 		fd_tracker_destroy(the_fd_tracker);
 	}
 
@@ -687,7 +692,6 @@ static void relayd_cleanup(void)
 	if (tracing_group_name_override) {
 		free((void *) tracing_group_name);
 	}
-	fd_tracker_log(the_fd_tracker);
 }
 
 /*
@@ -3987,6 +3991,39 @@ static int create_relay_conn_pipe(void)
 			"Relayd connection pipe", relay_conn_pipe);
 }
 
+static int stdio_open(void *data, int *fds)
+{
+	fds[0] = fileno(stdout);
+	fds[1] = fileno(stderr);
+	return 0;
+}
+
+static int noop_close(void *data, int *fds)
+{
+	return 0;
+}
+
+static int track_stdio(void)
+{
+	int fds[2];
+	const char *names[] = { "stdout", "stderr" };
+
+	return fd_tracker_open_unsuspendable_fd(the_fd_tracker, fds,
+			names, 2, stdio_open, NULL);
+}
+
+static void untrack_stdio(void)
+{
+	int fds[] = { fileno(stdout), fileno(stderr) };
+
+	/*
+	 * noop_close is used since we don't really want to close
+	 * the stdio output fds; we merely want to stop tracking them.
+	 */
+	(void) fd_tracker_close_unsuspendable_fd(the_fd_tracker,
+			fds, 2, noop_close, NULL);
+}
+
 /*
  * main
  */
@@ -4091,6 +4128,12 @@ int main(int argc, char **argv)
 		goto exit_options;
 	}
 
+	ret = track_stdio();
+	if (ret) {
+		retval = -1;
+		goto exit_options;
+	}
+
 	/* Initialize thread health monitoring */
 	health_relayd = health_app_create(NR_HEALTH_RELAYD_TYPES);
 	if (!health_relayd) {