ctdb-common: Add async version of shutdown in sock_daemon

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

Autobuild-User(master): Martin Schwenke <martins@samba.org>
Autobuild-Date(master): Tue Nov 21 08:58:45 CET 2017 on sn-devel-144

3 files changed, 110 insertions, 9 deletions

diff --git a/ctdb/common/sock_daemon.c b/ctdb/common/sock_daemon.c
index ce6f9230a6d..7554cd6da07 100644
--- a/ctdb/common/sock_daemon.c
+++ b/ctdb/common/sock_daemon.c
@@ -524,6 +524,7 @@ struct sock_daemon_run_state {
 	pid_t pid_watch;
 
 	int fd;
+	int exit_code;
 };
 
 static void sock_daemon_run_started(struct tevent_req *subreq);
@@ -535,6 +536,8 @@ static void sock_daemon_run_signal_handler(struct tevent_context *ev,
 static void sock_daemon_run_reconfigure(struct tevent_req *req);
 static void sock_daemon_run_reconfigure_done(struct tevent_req *subreq);
 static void sock_daemon_run_shutdown(struct tevent_req *req);
+static void sock_daemon_run_shutdown_done(struct tevent_req *subreq);
+static void sock_daemon_run_exit(struct tevent_req *req);
 static bool sock_daemon_run_socket_listen(struct tevent_req *req);
 static void sock_daemon_run_socket_fail(struct tevent_req *subreq);
 static void sock_daemon_run_watch_pid(struct tevent_req *subreq);
@@ -702,6 +705,8 @@ static void sock_daemon_run_signal_handler(struct tevent_context *ev,
 {
 	struct tevent_req *req = talloc_get_type_abort(
 		private_data, struct tevent_req);
+	struct sock_daemon_run_state *state = tevent_req_data(
+		req, struct sock_daemon_run_state);
 
 	D_NOTICE("Received signal %d\n", signum);
 
@@ -711,8 +716,8 @@ static void sock_daemon_run_signal_handler(struct tevent_context *ev,
 	}
 
 	if (signum == SIGINT || signum == SIGTERM) {
+		state->exit_code = EINTR;
 		sock_daemon_run_shutdown(req);
-		tevent_req_error(req, EINTR);
 	}
 }
 
@@ -770,6 +775,7 @@ static void sock_daemon_run_reconfigure_done(struct tevent_req *subreq)
 
 static void sock_daemon_run_shutdown(struct tevent_req *req)
 {
+	struct tevent_req *subreq;
 	struct sock_daemon_run_state *state = tevent_req_data(
 		req, struct sock_daemon_run_state);
 	struct sock_daemon_context *sockd = state->sockd;
@@ -782,11 +788,53 @@ static void sock_daemon_run_shutdown(struct tevent_req *req)
 		TALLOC_FREE(sock);
 	}
 
+	if (sockd->funcs != NULL && sockd->funcs->shutdown_send != NULL &&
+	    sockd->funcs->shutdown_recv != NULL) {
+		subreq = sockd->funcs->shutdown_send(state, state->ev,
+						     sockd->private_data);
+		if (subreq == NULL) {
+			sock_daemon_run_exit(req);
+			return;
+		}
+		tevent_req_set_callback(subreq, sock_daemon_run_shutdown_done,
+						req);
+		return;
+	}
+
 	if (sockd->funcs != NULL && sockd->funcs->shutdown != NULL) {
 		sockd->funcs->shutdown(sockd->private_data);
 	}
 
+	sock_daemon_run_exit(req);
+}
+
+static void sock_daemon_run_shutdown_done(struct tevent_req *subreq)
+{
+	struct tevent_req *req = tevent_req_callback_data(
+		subreq, struct tevent_req);
+	struct sock_daemon_run_state *state = tevent_req_data(
+		req, struct sock_daemon_run_state);
+	struct sock_daemon_context *sockd = state->sockd;
+
+	sockd->funcs->shutdown_recv(subreq);
+	TALLOC_FREE(subreq);
+
+	sock_daemon_run_exit(req);
+}
+
+static void sock_daemon_run_exit(struct tevent_req *req)
+{
+	struct sock_daemon_run_state *state = tevent_req_data(
+		req, struct sock_daemon_run_state);
+	struct sock_daemon_context *sockd = state->sockd;
+
 	TALLOC_FREE(sockd->pid_ctx);
+
+	if (state->exit_code == 0) {
+		tevent_req_done(req);
+	} else {
+		tevent_req_error(req, state->exit_code);
+	}
 }
 
 static bool sock_daemon_run_socket_listen(struct tevent_req *req)
@@ -826,13 +874,14 @@ static void sock_daemon_run_socket_fail(struct tevent_req *subreq)
 
 	status = sock_socket_start_recv(subreq, &ret, state, &sockpath);
 	TALLOC_FREE(subreq);
-	sock_daemon_run_shutdown(req);
 	if (! status) {
 		D_ERR("socket %s closed unexpectedly\n", sockpath);
-		tevent_req_error(req, ret);
+		state->exit_code = ret;
 	} else {
-		tevent_req_done(req);
+		state->exit_code = 0;
 	}
+
+	sock_daemon_run_shutdown(req);
 }
 
 static void sock_daemon_run_watch_pid(struct tevent_req *subreq)
@@ -855,8 +904,8 @@ static void sock_daemon_run_watch_pid(struct tevent_req *subreq)
 	if (ret == -1) {
 		if (errno == ESRCH) {
 			D_ERR("PID %d gone away, exiting\n", state->pid_watch);
+			state->exit_code = ESRCH;
 			sock_daemon_run_shutdown(req);
-			tevent_req_error(req, ESRCH);
 			return;
 		} else {
 			D_ERR("Failed to check PID status %d, ret=%d\n",
@@ -898,17 +947,18 @@ static void sock_daemon_run_wait_done(struct tevent_req *subreq)
 	struct sock_daemon_run_state *state = tevent_req_data(
 		req, struct sock_daemon_run_state);
 	struct sock_daemon_context *sockd = state->sockd;
-	int ret;
+	int ret = 0;
 	bool status;
 
 	status = sockd->funcs->wait_recv(subreq, &ret);
 	TALLOC_FREE(subreq);
-	sock_daemon_run_shutdown(req);
 	if (! status) {
-		tevent_req_error(req, ret);
+		state->exit_code = ret;
 	} else {
-		tevent_req_done(req);
+		state->exit_code = 0;
 	}
+
+	sock_daemon_run_shutdown(req);
 }
 
 bool sock_daemon_run_recv(struct tevent_req *req, int *perr)
diff --git a/ctdb/common/sock_daemon.h b/ctdb/common/sock_daemon.h
index 2cc94c6bf5d..a071833c2f3 100644
--- a/ctdb/common/sock_daemon.h
+++ b/ctdb/common/sock_daemon.h
@@ -63,6 +63,12 @@ struct sock_client_context;
  * shutdown() is called when process receives SIGINT or SIGTERM or
  *             when wait computation has finished
  *
+ * shutdown_send()/shutdown_recv() is the async version of shutdown()
+ *
+ * Please note that only one (sync or async) version of these functions
+ * will be called.  If both versions are defined, then only async function
+ * will be called.
+ *
  * wait_send() starts the async computation to keep running the daemon
  * wait_recv() ends the async computation to keep running the daemon
  *
@@ -86,6 +92,11 @@ struct sock_daemon_funcs {
 
 	void (*shutdown)(void *private_data);
 
+	struct tevent_req * (*shutdown_send)(TALLOC_CTX *mem_ctx,
+					     struct tevent_context *ev,
+					     void *private_data);
+	void (*shutdown_recv)(struct tevent_req *req);
+
 	struct tevent_req * (*wait_send)(TALLOC_CTX *mem_ctx,
 					 struct tevent_context *ev,
 					 void *private_data);
diff --git a/ctdb/tests/src/sock_daemon_test.c b/ctdb/tests/src/sock_daemon_test.c
index 05a5748fa6d..505ff78e768 100644
--- a/ctdb/tests/src/sock_daemon_test.c
+++ b/ctdb/tests/src/sock_daemon_test.c
@@ -297,6 +297,40 @@ static void test2_shutdown(void *private_data)
 	assert(nwritten == sizeof(ret));
 }
 
+struct test2_shutdown_state {
+	int fd;
+};
+
+static struct tevent_req *test2_shutdown_send(TALLOC_CTX *mem_ctx,
+					      struct tevent_context *ev,
+					      void *private_data)
+{
+	struct tevent_req *req;
+	struct test2_shutdown_state *state;
+
+	req = tevent_req_create(mem_ctx, &state,
+				struct test2_shutdown_state);
+	if (req == NULL) {
+		return NULL;
+	}
+
+	state->fd = *(int *)private_data;
+
+	tevent_req_done(req);
+	return tevent_req_post(req, ev);
+}
+
+static void test2_shutdown_recv(struct tevent_req *req)
+{
+	struct test2_shutdown_state *state = tevent_req_data(
+		req, struct test2_shutdown_state);
+	int ret = 3;
+	ssize_t nwritten;
+
+	nwritten = write(state->fd, &ret, sizeof(ret));
+	assert(nwritten == sizeof(ret));
+}
+
 static void test2(TALLOC_CTX *mem_ctx, const char *pidfile,
 		  const char *sockpath)
 {
@@ -405,6 +439,8 @@ static void test2(TALLOC_CTX *mem_ctx, const char *pidfile,
 			.startup = test2_startup,
 			.reconfigure_send = test2_reconfigure_send,
 			.reconfigure_recv = test2_reconfigure_recv,
+			.shutdown_send = test2_shutdown_send,
+			.shutdown_recv = test2_shutdown_recv,
 		};
 
 		close(fd[0]);
@@ -449,6 +485,10 @@ static void test2(TALLOC_CTX *mem_ctx, const char *pidfile,
 	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);