schema: fix bug when og_dbi_open cannot open a connection

When og_dbi_open cannot open a connection during schema update, then
ogServer crashes.

og_dbi_open returns NULL when it cannot open a DB connection.

Do not use dbi variable if og_dbi_open is unable to open a DB
connection.

Add syslog message when database schema couldn't be updated.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/main.c b/src/main.c
index c4148a5..d8453de 100644
--- a/src/main.c
+++ b/src/main.c
@@ -92,8 +92,10 @@ int main(int argc, char *argv[])
 	ev_io_init(&ev_io_agent_rest, og_server_accept_cb, socket_agent_rest, EV_READ);
 	ev_io_start(og_loop, &ev_io_agent_rest);
 
-	if (og_dbi_schema_update() < 0)
+	if (og_dbi_schema_update() < 0) {
+		syslog(LOG_ERR, "Cannot update the database schema\n");
 		exit(EXIT_FAILURE);
+	}
 
 	if (og_dbi_schedule_get() < 0) {
 		syslog(LOG_ERR, "Cannot connect to database\n");