|
 |
2b72d0 |
From 1db09d30138c54de64f8e197eb6d60b8a04d31c8 Mon Sep 17 00:00:00 2001
|
|
|
2b72d0 |
From: Mikel Astiz <mikel.astiz@bmw-carit.de>
|
|
|
2b72d0 |
Date: Wed, 30 Jan 2013 09:30:31 +0100
|
|
|
2b72d0 |
Subject: [PATCH 7/7] reserve: Fix leaking NameLost signals after
|
|
|
2b72d0 |
release+acquire
|
|
|
2b72d0 |
|
|
|
2b72d0 |
The use of the pseudo-blocking D-Bus calls leads to the problem that
|
|
|
2b72d0 |
NameLost signals are received after the reply to ReleaseName().
|
|
|
2b72d0 |
|
|
|
2b72d0 |
The problem with this is that a later acquisition of the same audio
|
|
|
2b72d0 |
device can potentially receive the NameLost signal corresponding to
|
|
|
2b72d0 |
the previous instance, due to the fact that the signal hasn't been
|
|
|
2b72d0 |
popped from the D-Bus message queue.
|
|
|
2b72d0 |
|
|
|
2b72d0 |
The simplest approach to solve this problem is to poll the actual name
|
|
|
2b72d0 |
owner from the D-Bus daemon, in order to make sure that we did really
|
|
|
2b72d0 |
lose the name.
|
|
|
2b72d0 |
|
|
|
2b72d0 |
The proposal uses a blocking call to GetNameOwner to avoid incosistent
|
|
|
2b72d0 |
states in the internal APIs: it would otherwise be possible to have a
|
|
|
2b72d0 |
"busy" device before the reservation has been lost, in the unlikely
|
|
|
2b72d0 |
case if some other process acquires the name before we got the
|
|
|
2b72d0 |
confirmation that the NameLost was actually true.
|
|
|
2b72d0 |
---
|
|
|
2b72d0 |
src/modules/reserve.c | 17 +++++++++++++++++
|
|
|
2b72d0 |
1 file changed, 17 insertions(+)
|
|
|
2b72d0 |
|
|
|
2b72d0 |
diff --git a/src/modules/reserve.c b/src/modules/reserve.c
|
|
|
2b72d0 |
index bbb6773..f78805e 100644
|
|
|
2b72d0 |
--- a/src/modules/reserve.c
|
|
|
2b72d0 |
+++ b/src/modules/reserve.c
|
|
|
2b72d0 |
@@ -293,6 +293,7 @@ static DBusHandlerResult filter_handler(
|
|
|
2b72d0 |
|
|
|
2b72d0 |
rd_device *d;
|
|
|
2b72d0 |
DBusError error;
|
|
|
2b72d0 |
+ char *name_owner = NULL;
|
|
|
2b72d0 |
|
|
|
2b72d0 |
dbus_error_init(&error);
|
|
|
2b72d0 |
|
|
|
2b72d0 |
@@ -310,6 +311,21 @@ static DBusHandlerResult filter_handler(
|
|
|
2b72d0 |
goto invalid;
|
|
|
2b72d0 |
|
|
|
2b72d0 |
if (strcmp(name, d->service_name) == 0 && d->owning) {
|
|
|
2b72d0 |
+ /* Verify the actual owner of the name to avoid leaked NameLost
|
|
|
2b72d0 |
+ * signals from previous reservations. The D-Bus daemon will send
|
|
|
2b72d0 |
+ * all messages asynchronously in the correct order, but we could
|
|
|
2b72d0 |
+ * potentially process them too late due to the pseudo-blocking
|
|
|
2b72d0 |
+ * call mechanism used during both acquisition and release. This
|
|
|
2b72d0 |
+ * can happen if we release the device and immediately after
|
|
|
2b72d0 |
+ * reacquire it before NameLost is processed. */
|
|
|
2b72d0 |
+ if (!d->gave_up) {
|
|
|
2b72d0 |
+ const char *un;
|
|
|
2b72d0 |
+
|
|
|
2b72d0 |
+ if ((un = dbus_bus_get_unique_name(c)) && rd_dbus_get_name_owner(c, d->service_name, &name_owner, &error) == 0)
|
|
|
2b72d0 |
+ if (strcmp(name_owner, un) == 0)
|
|
|
2b72d0 |
+ goto invalid; /* Name still owned by us */
|
|
|
2b72d0 |
+ }
|
|
|
2b72d0 |
+
|
|
|
2b72d0 |
d->owning = 0;
|
|
|
2b72d0 |
|
|
|
2b72d0 |
if (!d->gave_up) {
|
|
|
2b72d0 |
@@ -326,6 +342,7 @@ static DBusHandlerResult filter_handler(
|
|
|
2b72d0 |
}
|
|
|
2b72d0 |
|
|
|
2b72d0 |
invalid:
|
|
|
2b72d0 |
+ free(name_owner);
|
|
|
2b72d0 |
dbus_error_free(&error);
|
|
|
2b72d0 |
|
|
|
2b72d0 |
return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
|
|
|
2b72d0 |
--
|
|
|
2b72d0 |
1.8.1.4
|
|
|
2b72d0 |
|