[PATCH 2/3] subscr: Make db_create_subscriber fail on duplicates

[Holger Freyther]

From: Holger Hans Peter Freyther <holger at moiji-mobile.com>

The issue of db_create_subscriber updating an already existing subcr
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.

Related: OS Issue #1657
---
 openbsc/src/libmsc/db.c                   | 10 ++--------
 openbsc/src/libmsc/vty_interface_layer3.c | 16 +++++++++++-----
 openbsc/tests/db/db_test.c                |  6 +++++-
 3 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/openbsc/src/libmsc/db.c b/openbsc/src/libmsc/db.c
index 0935fc5..17bea24 100644
--- a/openbsc/src/libmsc/db.c
+++ b/openbsc/src/libmsc/db.c
@@ -508,14 +508,8 @@ struct gsm_subscriber *db_create_subscriber(const char *imsi)
 	/* Is this subscriber known in the db? */
 	subscr = db_get_subscriber(GSM_SUBSCRIBER_IMSI, imsi);
 	if (subscr) {
-		result = dbi_conn_queryf(conn,
-                         "UPDATE Subscriber set updated = datetime('now') "
-                         "WHERE imsi = %s " , imsi);
-		if (!result)
-			LOGP(DDB, LOGL_ERROR, "failed to update timestamp\n");
-		else
-			dbi_result_free(result);
-		return subscr;
+		subscr_put(subscr);
+		return NULL;
 	}
 
 	subscr = subscr_alloc();
diff --git a/openbsc/src/libmsc/vty_interface_layer3.c b/openbsc/src/libmsc/vty_interface_layer3.c
index f49c53a..790fedf 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. */
diff --git a/openbsc/tests/db/db_test.c b/openbsc/tests/db/db_test.c
index a02d1f8..fb159a5 100644
--- a/openbsc/tests/db/db_test.c
+++ b/openbsc/tests/db/db_test.c
@@ -1,5 +1,5 @@
 /* (C) 2008 by Jan Luebbe <jluebbe at debian.org>
- * (C) 2009 by Holger Hans Peter Freyther <zecke at selfish.org>
+ * (C) 2009-2016 by Holger Hans Peter Freyther <zecke at selfish.org>
  * (C) 2014 by Alexander Chemeris <Alexander.Chemeris at fairwaves.co>
  * All Rights Reserved
  *
@@ -246,6 +246,10 @@ int main()
 	SUBSCR_PUT(alice_db);
 	SUBSCR_PUT(alice);
 
+	/* create it again and see it fails */
+	alice = db_create_subscriber(alice_imsi);
+	OSMO_ASSERT(!alice);
+
 	test_sms();
 	test_sms_migrate();
 
-- 
2.6.3