ctdb-tests: Add a sock_daemon test for PID file contention

Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>

ctdb/tests/cunit/sock_daemon_test_001.sh

@@ -65,3 +65,10 @@ test6[PID]: daemon started, pid=PID
 test6[PID]: Shutting down
 EOF
 unit_test sock_daemon_test "$pidfile" "$sockpath" 6
+
+ok <<EOF
+test7[PID]: daemon started, pid=PID
+test7[PID]: Received signal 15
+test7[PID]: Shutting down
+EOF
+unit_test sock_daemon_test "$pidfile" "$sockpath" 7

ctdb/tests/src/sock_daemon_test.c

@@ -990,6 +990,81 @@ static void test6(TALLOC_CTX *mem_ctx, const char *pidfile,
 	assert(pid != -1);
 }
 
+/*
+ * test7
+ *
+ * Start daemon twice, confirm PID file contention
+ */
+
+static void test7(TALLOC_CTX *mem_ctx, const char *pidfile,
+		  const char *sockpath)
+{
+	struct stat st;
+	int fd[2];
+	pid_t pid, pid2;
+	int ret;
+	struct tevent_context *ev;
+	struct sock_daemon_context *sockd;
+	ssize_t n;
+
+	ret = pipe(fd);
+	assert(ret == 0);
+
+	pid = fork();
+	assert(pid != -1);
+
+	if (pid == 0) {
+		close(fd[0]);
+
+		ev = tevent_context_init(mem_ctx);
+		assert(ev != NULL);
+
+		/* Reuse test2 funcs for the startup synchronisation */
+		ret = sock_daemon_setup(mem_ctx, "test7", "file:", "NOTICE",
+					&test2_funcs, &fd[1], &sockd);
+		assert(ret == 0);
+
+		ret = sock_daemon_run(ev, sockd, pidfile, -1);
+		assert(ret == EINTR);
+
+		exit(0);
+	}
+
+	close(fd[1]);
+
+	n = read(fd[0], &ret, sizeof(ret));
+	assert(n == sizeof(ret));
+	assert(ret == 1);
+
+	ret = stat(pidfile, &st);
+	assert(ret == 0);
+	assert(S_ISREG(st.st_mode));
+
+	ev = tevent_context_init(mem_ctx);
+	assert(ev != NULL);
+
+	/* Reuse test2 funcs for the startup synchronisation */
+	ret = sock_daemon_setup(mem_ctx, "test7-parent", "file:", "NOTICE",
+				&test2_funcs, &fd[1], &sockd);
+	assert(ret == 0);
+
+	ret = sock_daemon_run(ev, sockd, pidfile, -1);
+	assert(ret == EEXIST);
+
+	ret = kill(pid, SIGTERM);
+	assert(ret == 0);
+
+	n = read(fd[0], &ret, sizeof(ret));
+	assert(n == sizeof(ret));
+	assert(ret == 3);
+
+	pid2 = waitpid(pid, &ret, 0);
+	assert(pid2 == pid);
+	assert(WEXITSTATUS(ret) == 0);
+
+	close(fd[0]);
+}
+
 int main(int argc, const char **argv)
 {
 	TALLOC_CTX *mem_ctx;
@@ -1033,6 +1108,10 @@ int main(int argc, const char **argv)
 		test6(mem_ctx, pidfile, sockpath);
 		break;
 
+	case 7:
+		test7(mem_ctx, pidfile, sockpath);
+		break;
+
 	default:
 		fprintf(stderr, "Unknown test number %d\n", num);
 	}