X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Fbin%2Flttng%2Flttng.c;h=aeaad1469725db898871c6a644f1b2a00119d8a7;hb=5a532b6873b6d619381c0188b91e48106e639808;hp=64f3efa446530ed61663c9434eb77251cc923c91;hpb=679b4943c3b0f451e7f4fbcd804dd8a7a679e253;p=lttng-tools.git

diff --git a/src/bin/lttng/lttng.c b/src/bin/lttng/lttng.c
index 64f3efa44..aeaad1469 100644
--- a/src/bin/lttng/lttng.c
+++ b/src/bin/lttng/lttng.c
@@ -40,6 +40,7 @@ int opt_verbose;
 static int opt_no_sessiond;
 static char *opt_sessiond_path;
 static pid_t sessiond_pid;
+static volatile int recv_child_signal;
 
 enum {
 	OPT_SESSION_PATH,
@@ -181,12 +182,14 @@ static void sighandler(int sig)
 		case SIGCHLD:
 			DBG("SIGCHLD caugth");
 			waitpid(sessiond_pid, &status, 0);
+			recv_child_signal = 1;
 			/* Indicate that the session daemon died */
 			sessiond_pid = 0;
 			ERR("Session daemon died (exit status %d)", WEXITSTATUS(status));
 			break;
 		case SIGUSR1:
 			/* Notify is done */
+			recv_child_signal = 1;
 			DBG("SIGUSR1 caugth");
 			break;
 		default:
@@ -294,6 +297,7 @@ static int spawn_sessiond(char *pathname)
 	pid_t pid;
 
 	MSG("Spawning a session daemon");
+	recv_child_signal = 0;
 	pid = fork();
 	if (pid == 0) {
 		/*
@@ -307,12 +311,24 @@ static int spawn_sessiond(char *pathname)
 		} else {
 			perror("execlp");
 		}
-		kill(getppid(), SIGTERM);	/* unpause parent */
+		kill(getppid(), SIGTERM);	/* wake parent */
 		exit(EXIT_FAILURE);
 	} else if (pid > 0) {
 		sessiond_pid = pid;
-		/* Wait for lttng-sessiond to start */
-		pause();
+		/*
+		 * Wait for lttng-sessiond to start. We need to use a
+		 * flag to check if the signal has been sent to us,
+		 * because the child can be scheduled before the parent,
+		 * and thus send the signal before this check. In the
+		 * signal handler, we set the recv_child_signal flag, so
+		 * anytime we check it after the fork is fine. Note that
+		 * sleep() is interrupted before the 1 second delay as
+		 * soon as the signal is received, so it will not cause
+		 * visible delay for the user.
+		 */
+		while (!recv_child_signal) {
+			sleep(1);
+		}
 		if (!sessiond_pid) {
 			exit(EXIT_FAILURE);
 		}
@@ -351,7 +367,7 @@ static int check_sessiond(void)
 			pathname = opt_sessiond_path;
 		} else {
 			/* Try LTTNG_SESSIOND_PATH env variable */
-			pathname = getenv(LTTNG_SESSIOND_PATH_ENV);
+			pathname = getenv(DEFAULT_SESSIOND_PATH_ENV);
 		}
 
 		/* Let's rock and roll */
@@ -387,9 +403,9 @@ static int check_args_no_sessiond(int argc, char **argv)
 	int i;
 
 	for (i = 0; i < argc; i++) {
-		if ((strncmp(argv[i], "-h", 2) == 0) ||
-				strncmp(argv[i], "--h", 3) == 0 ||
-				strncmp(argv[i], "--list-options", 14)) {
+		if ((strncmp(argv[i], "-h", sizeof("-h")) == 0) ||
+				strncmp(argv[i], "--h", sizeof("--h")) == 0 ||
+				strncmp(argv[i], "--list-options", sizeof("--list-options")) == 0) {
 			return 1;
 		}
 	}
@@ -494,8 +510,9 @@ int main(int argc, char *argv[])
 	progname = argv[0] ? argv[0] : "lttng";
 
 	/* For Mathieu Desnoyers aka Dr Tracing */
-	if (strncmp(progname, "drtrace", 7) == 0) {
-		MSG("%c[%d;%dmWelcome back Dr Tracing!%c[%dm\n\n", 27,1,33,27,0);
+	if (strncmp(progname, "drtrace", 7) == 0 ||
+			strncmp("compudj", getenv("USER"), 7) == 0) {
+		MSG("%c[%d;%dmWelcome back Dr Tracing!%c[%dm\n", 27,1,33,27,0);
 	}
 
 	ret = set_signal_handler();