ctdb-client: Add a disconnect callback for ctdb client

This allows the client code to optionally clean up and/or re-connect to
CTDB daemon when it the daemon goes away.  If no disconnect callback is
registered and CTDB daemon goes away, then the client will terminate.

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

3 files changed, 25 insertions, 1 deletions

diff --git a/ctdb/client/client.h b/ctdb/client/client.h
index 3a160697536..bce0c6b39b9 100644
--- a/ctdb/client/client.h
+++ b/ctdb/client/client.h
@@ -30,11 +30,17 @@ struct ctdb_client_context;
 struct ctdb_db_context;
 struct ctdb_record_handle;
 
+typedef void (*ctdb_client_callback_func_t)(void *private_data);
+
 /* from client/client_connect.c */
 
 int ctdb_client_init(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
 		     const char *sockpath, struct ctdb_client_context **ret);
 
+void ctdb_client_set_disconnect_callback(struct ctdb_client_context *client,
+					 ctdb_client_callback_func_t func,
+					 void *private_data);
+
 uint32_t ctdb_client_pnn(struct ctdb_client_context *client);
 
 void ctdb_client_wait(struct tevent_context *ev, bool *done);
diff --git a/ctdb/client/client_connect.c b/ctdb/client/client_connect.c
index 8cff21307db..d433f7ddc3f 100644
--- a/ctdb/client/client_connect.c
+++ b/ctdb/client/client_connect.c
@@ -206,12 +206,27 @@ static void client_dead_handler(void *private_data)
 {
 	struct ctdb_client_context *client = talloc_get_type_abort(
 		private_data, struct ctdb_client_context);
+	ctdb_client_callback_func_t callback = client->callback;
+	void *callback_data = client->private_data;
 
-	DEBUG(DEBUG_NOTICE, ("connection to daemon closed, exiting\n"));
 	talloc_free(client);
+	if (callback != NULL) {
+		callback(callback_data);
+		return;
+	}
+
+	DEBUG(DEBUG_NOTICE, ("connection to daemon closed, exiting\n"));
 	exit(1);
 }
 
+void ctdb_client_set_disconnect_callback(struct ctdb_client_context *client,
+					 ctdb_client_callback_func_t callback,
+					 void *private_data)
+{
+	client->callback = callback;
+	client->private_data = private_data;
+}
+
 uint32_t ctdb_client_pnn(struct ctdb_client_context *client)
 {
 	return client->pnn;
diff --git a/ctdb/client/client_private.h b/ctdb/client/client_private.h
index b1d8d4b8c5b..7ea9b129202 100644
--- a/ctdb/client/client_private.h
+++ b/ctdb/client/client_private.h
@@ -21,6 +21,7 @@
 #define __CTDB_CLIENT_PRIVATE_H__
 
 #include "protocol/protocol.h"
+#include "client/client.h"
 
 struct ctdb_db_context {
 	struct ctdb_db_context *prev, *next;
@@ -35,6 +36,8 @@ struct ctdb_client_context {
 	struct reqid_context *idr;
 	struct srvid_context *srv;
 	struct comm_context *comm;
+	ctdb_client_callback_func_t callback;
+	void *private_data;
 	int fd;
 	uint32_t pnn;
 	struct ctdb_db_context *db;