Synchronize tests execution with fifo pipe

tests/run.sh

@@ -23,6 +23,10 @@ BOLD='\033[1m'
 NOFMT='\033[0m'
 
 TEST_CNT=0
+TEST_PIPE=./test-pipe
+
+# remove stale test pipe (if any)
+rm $TEST_PIPE
 
 do_memcr_test()
 {
@@ -32,12 +36,15 @@ do_memcr_test()
 	TEST_CNT=$((TEST_CNT + 1))
 	echo "${WHITE}[test $TEST_CNT] $MEMCR_CMD for $TEST${NOFMT}"
 
+	mkfifo $TEST_PIPE
+
 	# start the test
-	./$TEST &
+	./$TEST $TEST_PIPE &
 	TPID=$!
 
-	# wait
-	sleep 0.05
+	# wait for test to be ready
+	cat $TEST_PIPE
+	rm $TEST_PIPE
 
 	# memcr
 	$MEMCR_CMD -p $TPID

tests/test-malloc.c

@@ -21,11 +21,30 @@ static void sighandler(int num)
 	signalled = num;
 }
 
+static void notify_ready(const char *pipe)
+{
+	int ret;
+	int fd;
+	char msg[64];
+
+	fd = open(pipe, O_WRONLY);
+	assert(fd >= 0);
+
+	snprintf(msg, sizeof(msg), PFX "pid %d ready\n", getpid());
+	ret = write(fd, msg, strlen(msg));
+	assert(ret == strlen(msg));
+
+	close(fd);
+}
+
 int main(int argc, char *argv[])
 {
 	int ret;
 	void *memb;
 
+	if (argc < 2)
+		return 1;
+
 	signal(SIGUSR1, sighandler);
 
 	printf(PFX "pid %d\n", getpid());
@@ -46,6 +65,8 @@ int main(int argc, char *argv[])
 
 	printf(PFX "waiting for SIGUSR1\n");
 
+	notify_ready(argv[1]);
+
 	while (!signalled)
 		usleep(10 * 1000);