From: Pierre-Marc Fournier <pierre-marc.fournier@polymtl.ca>
Date: Tue, 13 Oct 2009 21:47:24 +0000 (-0400)
Subject: immediately create listener thread on process creation
X-Git-Tag: v1.9.1~865
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=2944a62989b8466e0d551e37a0be0e8e6cd69905;p=lttng-ust.git

immediately create listener thread on process creation

It is complex to create a thread properly inside a signal handler.
Leave this aside for now. This optimization can always be added
later.
---

diff --git a/libust/tracectl.c b/libust/tracectl.c
index 2d4341d3..d4cd5942 100644
--- a/libust/tracectl.c
+++ b/libust/tracectl.c
@@ -798,61 +798,11 @@ void create_listener(void)
 	have_listener = 1;
 }
 
-/* The signal handler itself. Signals must be setup so there cannot be
-   nested signals. */
-
-void sighandler(int sig)
-{
-	DBG("sighandler");
-
-	if(!have_listener) {
-		create_listener();
-	}
-}
-
-/* Called by the app signal handler to chain it to us. */
-
-void chain_signal(void)
-{
-	sighandler(USTSIGNAL);
-}
-
 static int init_socket(void)
 {
 	return ustcomm_init_app(getpid(), &ustcomm_app);
 }
 
-static int init_signal_handler(void)
-{
-	/* Attempt to handler SIGIO. If the main program wants to
-	 * handle it, fine, it'll override us. They it'll have to
-	 * use the chaining function.
-	 */
-
-	int result;
-	struct sigaction act;
-
-	result = sigemptyset(&act.sa_mask);
-	if(result == -1) {
-		PERROR("sigemptyset");
-		return -1;
-	}
-
-	act.sa_handler = sighandler;
-	act.sa_flags = SA_RESTART;
-
-	/* Only defer ourselves. Also, try to restart interrupted
-	 * syscalls to disturb the traced program as little as possible.
-	 */
-	result = sigaction(SIGIO, &act, NULL);
-	if(result == -1) {
-		PERROR("sigaction");
-		return -1;
-	}
-
-	return 0;
-}
-
 #define AUTOPROBE_DISABLED      0
 #define AUTOPROBE_ENABLE_ALL    1
 #define AUTOPROBE_ENABLE_REGEX  2
@@ -916,11 +866,8 @@ static void __attribute__((constructor)) init()
 		ERR("init_socket error");
 		return;
 	}
-	result = init_signal_handler();
-	if(result == -1) {
-		ERR("init_signal_handler error");
-		return;
-	}
+
+	create_listener();
 
 	autoprobe_val = getenv("UST_AUTOPROBE");
 	if(autoprobe_val) {
diff --git a/libustcomm/ustcomm.c b/libustcomm/ustcomm.c
index 6044c271..1b6843bf 100644
--- a/libustcomm/ustcomm.c
+++ b/libustcomm/ustcomm.c
@@ -67,22 +67,11 @@ char *strdup_malloc(const char *s)
 
 static int signal_process(pid_t pid)
 {
-	int result;
-
-	result = kill(pid, UST_SIGNAL);
-	if(result == -1) {
-		PERROR("kill");
-		return -1;
-	}
-
-	/* FIXME: should wait in a better way */
-	//sleep(1);
-
 	return 0;
 }
 
 int pid_is_online(pid_t pid) {
-	return kill(pid, UST_SIGNAL) != -1;
+	return 1;
 }
 
 static int send_message_fd(int fd, const char *msg)