subscr: Make db_create_subscriber fail on duplicates

The issue of db_create_subscriber updating an already existing subscr
is that the same subscriber will then have two entries in the active
subscribers list. In general this will break assumptions that a subscr
can be compared by comparing the pointer.

In the case of the VTY this was not an issue as the created subscr
was immediately destroyed again but it is better to avoid this problem.

Change the VTY command to find the subscriber and then call sync to
have the updated time set. The side-effect is we will now have two
queries for the subscriber. Once through subscr_get_by_imsi and once
through db_create_subscriber.

Change the db_create_subscriber to fail if a subscriber already exists,
and add a testcase for this behavior and do not updated the 'updated'
timestamp of an already existing subscriber.

Add a testcase for this behavior.

Related: OS Issue #1657

1 files changed, 11 insertions, 5 deletions

diff --git a/openbsc/src/libmsc/vty_interface_layer3.c b/openbsc/src/libmsc/vty_interface_layer3.c
index f49c53a08..790fedf39 100644
--- a/openbsc/src/libmsc/vty_interface_layer3.c
+++ b/openbsc/src/libmsc/vty_interface_layer3.c
@@ -236,11 +236,17 @@ DEFUN(subscriber_create,
 	struct gsm_network *gsmnet = gsmnet_from_vty(vty);
 	struct gsm_subscriber *subscr;
 
-	subscr = subscr_create_subscriber(gsmnet->subscr_group, argv[0]);
-	if (!subscr) {
-		vty_out(vty, "%% No subscriber created for IMSI %s%s",
-			argv[0], VTY_NEWLINE);
-		return CMD_WARNING;
+	subscr = subscr_get_by_imsi(gsmnet->subscr_group, argv[0]);
+	if (subscr)
+		db_sync_subscriber(subscr);
+	else {
+		subscr = subscr_create_subscriber(gsmnet->subscr_group, argv[0]);
+
+		if (!subscr) {
+			vty_out(vty, "%% No subscriber created for IMSI %s%s",
+				argv[0], VTY_NEWLINE);
+			return CMD_WARNING;
+		}
 	}
 
 	/* Show info about the created subscriber. */