trace-cmd: Add debug option to tell msg protocol not to timeout

In order to debug the message protocol, we do not want to time out, as we
need to run gdb on the client and server, and timeouts kill the connections
we want to debug.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

4 files changed, 26 insertions, 1 deletions

diff --git a/trace-cmd.h b/trace-cmd.h
index 451771a8..cef2458a 100644
--- a/trace-cmd.h
+++ b/trace-cmd.h
@@ -285,6 +285,9 @@ int tracecmd_msg_initial_setting(int fd, int *cpus, int *pagesize);
 int tracecmd_msg_send_port_array(int fd, int total_cpus, int *ports);
 int tracecmd_msg_collect_metadata(int ifd, int ofd);
 
+/* msg debugging */
+void tracecmd_msg_set_debug(int debug);
+
 /* --- Plugin handling --- */
 extern struct pevent_plugin_option trace_ftrace_options[];
 
diff --git a/trace-listen.c b/trace-listen.c
index 16375f82..420b68d4 100644
--- a/trace-listen.c
+++ b/trace-listen.c
@@ -936,6 +936,9 @@ void trace_listen(int argc, char **argv)
 	signal_setup(SIGINT, finish);
 	signal_setup(SIGTERM, finish);
 
+	if (debug)
+		tracecmd_msg_set_debug(debug);
+
 	do_listen(port);
 
 	return;
diff --git a/trace-msg.c b/trace-msg.c
index cacdc1c9..98c330aa 100644
--- a/trace-msg.c
+++ b/trace-msg.c
@@ -411,6 +411,15 @@ error:
 }
 
 #define MSG_WAIT_MSEC	5000
+static int msg_wait_to = MSG_WAIT_MSEC;
+
+void tracecmd_msg_set_debug(int debug)
+{
+	if (debug)
+		msg_wait_to = -1;
+	else
+		msg_wait_to = MSG_WAIT_MSEC;
+}
 
 /*
  * A return value of 0 indicates time-out
@@ -422,7 +431,7 @@ static int tracecmd_msg_recv_wait(int fd, struct tracecmd_msg *msg)
 
 	pfd.fd = fd;
 	pfd.events = POLLIN;
-	ret = poll(&pfd, 1, MSG_WAIT_MSEC);
+	ret = poll(&pfd, 1, msg_wait_to);
 	if (ret < 0)
 		return -errno;
 	else if (ret == 0)
diff --git a/trace-record.c b/trace-record.c
index 4706f90e..e4839943 100644
--- a/trace-record.c
+++ b/trace-record.c
@@ -4103,6 +4103,7 @@ void update_first_instance(struct buffer_instance *instance, int topt)
 }
 
 enum {
+	OPT_debug	= 247,
 	OPT_tsoffset	= 249,
 	OPT_bycomm	= 250,
 	OPT_stderr	= 251,
@@ -4142,6 +4143,7 @@ void trace_record (int argc, char **argv)
 	int topt = 0;
 	int do_child = 0;
 	int data_flags = 0;
+	int debug = 0;
 
 	int c;
 
@@ -4309,6 +4311,7 @@ void trace_record (int argc, char **argv)
 			{"stderr", no_argument, NULL, OPT_stderr},
 			{"by-comm", no_argument, NULL, OPT_bycomm},
 			{"ts-offset", required_argument, NULL, OPT_tsoffset},
+			{"debug", no_argument, NULL, OPT_debug},
 			{"help", no_argument, NULL, '?'},
 			{NULL, 0, NULL, 0}
 		};
@@ -4571,6 +4574,9 @@ void trace_record (int argc, char **argv)
 				die("Can not use both --date and --ts-offset");
 			data_flags |= DATA_FL_OFFSET;
 			break;
+		case OPT_debug:
+			debug = 1;
+			break;
 		default:
 			usage(argv);
 		}
@@ -4598,6 +4604,10 @@ void trace_record (int argc, char **argv)
 	if (profile && !buffer_instances)
 		top_instance.profile = 1;
 
+	/* Let msg protocol know if we are debugging */
+	if (debug)
+		tracecmd_msg_set_debug(debug);
+
 	/*
 	 * If top_instance doesn't have any plugins or events, then
 	 * remove it from being processed.