[tracker] libtracker-common: Fix use-after-free memory error in tracker-dbus

[Jürg Billeter <juergbi src gnome org>]

commit 5724eed7cadf2906bfee381393da8b669b0fc60d
Author: Jürg Billeter <j bitron ch>
Date:   Mon Jan 17 14:42:40 2011 +0100

    libtracker-common: Fix use-after-free memory error in tracker-dbus
    
    If a single request was taking longer than 5 minutes, client data was
    freed but still used later on.

 src/libtracker-common/tracker-dbus.c |   16 ++++++++++++++--
 1 files changed, 14 insertions(+), 2 deletions(-)
---
diff --git a/src/libtracker-common/tracker-dbus.c b/src/libtracker-common/tracker-dbus.c
index f949d18..47371bb 100644
--- a/src/libtracker-common/tracker-dbus.c
+++ b/src/libtracker-common/tracker-dbus.c
@@ -38,6 +38,7 @@ typedef struct {
 	gchar *binary;
 	gulong pid;
 	guint clean_up_id;
+	gint n_active_requests;
 } ClientData;
 
 struct _TrackerDBusRequest {
@@ -241,11 +242,14 @@ client_get_for_sender (const gchar *sender)
 		sender_dup = g_strdup (sender);
 		cd = client_data_new (sender_dup);
 		g_hash_table_insert (clients, sender_dup, cd);
-	} else {
+	}
+
+	if (cd->clean_up_id) {
 		g_source_remove (cd->clean_up_id);
+		cd->clean_up_id = 0;
 	}
 
-	cd->clean_up_id = g_timeout_add_seconds (CLIENT_CLEAN_UP_TIME, client_clean_up_cb, cd);
+	cd->n_active_requests++;
 
 	return cd;
 }
@@ -336,6 +340,14 @@ tracker_dbus_request_end (TrackerDBusRequest *request,
 			   error->message);
 	}
 
+	if (request->cd) {
+		request->cd->n_active_requests--;
+
+		if (request->cd->n_active_requests == 0) {
+			request->cd->clean_up_id = g_timeout_add_seconds (CLIENT_CLEAN_UP_TIME, client_clean_up_cb, request->cd);
+		}
+	}
+
 	g_slice_free (TrackerDBusRequest, request);
 }