usbredir: Check for existing usb channels after libusb init

Currently trying to view a usbredir enabled vm from virt-manager causes
virt-manager to crash. This crash is caused by the following happening:

-virt-manager sets up the session, including connecting all the channels
-a spice-gtk internal code path calls spice_usb_device_manager_get()
-spice_usb_device_manager_get calls channel_new on all already connected
 usb channels
-channel_new does:
 spice_usbredir_channel_set_context(SPICE_USBREDIR_CHANNEL(channel),
                                    self->priv->context);
-But self->priv->context has not been set yet (so is NULL) -> segfault!

This patch fixes this by moving the iterating over already connected
usb channels to after the setting of self->priv->context. Note this means
that the channels will no longer get checked when there is no USB_REDIR
support. That is not a problem since spice_usb_device_manager_initable_init
will return FALSE in that case anyways.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 21 insertions, 24 deletions

diff --git a/gtk/usb-device-manager.c b/gtk/usb-device-manager.c
index 29e9b4c..14b60c9 100644
--- a/gtk/usb-device-manager.c
+++ b/gtk/usb-device-manager.c
@@ -64,9 +64,2 @@
 /* ------------------------------------------------------------------ */
-/* Prototypes for private functions */
-static void channel_new(SpiceSession *session, SpiceChannel *channel,
-                        gpointer user_data);
-static void channel_destroy(SpiceSession *session, SpiceChannel *channel,
-                            gpointer user_data);
-
-/* ------------------------------------------------------------------ */
 /* gobject glue                                                       */
@@ -111,2 +104,6 @@ struct _SpiceUsbDeviceManagerPrivate {
 #ifdef USE_USBREDIR
+static void channel_new(SpiceSession *session, SpiceChannel *channel,
+                        gpointer user_data);
+static void channel_destroy(SpiceSession *session, SpiceChannel *channel,
+                            gpointer user_data);
 static void spice_usb_device_manager_uevent_cb(GUdevClient     *client,
@@ -150,4 +147,2 @@ static gboolean spice_usb_device_manager_initable_init(GInitable  *initable,
 {
-    GList *list;
-    GList *it;
     SpiceUsbDeviceManager *self;
@@ -155,2 +150,4 @@ static gboolean spice_usb_device_manager_initable_init(GInitable  *initable,
 #ifdef USE_USBREDIR
+    GList *list;
+    GList *it;
     int rc;
@@ -177,13 +174,4 @@ static gboolean spice_usb_device_manager_initable_init(GInitable  *initable,
 
-    g_signal_connect(priv->session, "channel-new",
-                     G_CALLBACK(channel_new), self);
-    g_signal_connect(priv->session, "channel-destroy",
-                     G_CALLBACK(channel_destroy), self);
-    list = spice_session_get_channels(priv->session);
-    for (it = g_list_first(list); it != NULL; it = g_list_next(it)) {
-        channel_new(priv->session, it->data, (gpointer*)self);
-    }
-    g_list_free(list);
-
 #ifdef USE_USBREDIR
+    /* Initialize libusb */
     rc = libusb_init(&priv->context);
@@ -197,2 +185,14 @@ static gboolean spice_usb_device_manager_initable_init(GInitable  *initable,
 
+    /* Start listening for usb channels connect/disconnect */
+    g_signal_connect(priv->session, "channel-new",
+                     G_CALLBACK(channel_new), self);
+    g_signal_connect(priv->session, "channel-destroy",
+                     G_CALLBACK(channel_destroy), self);
+    list = spice_session_get_channels(priv->session);
+    for (it = g_list_first(list); it != NULL; it = g_list_next(it)) {
+        channel_new(priv->session, it->data, (gpointer*)self);
+    }
+    g_list_free(list);
+
+    /* Start listening for usb devices plug / unplug */
     priv->udev = g_udev_client_new(subsystems);
@@ -462,2 +462,4 @@ static void spice_usb_device_manager_class_init(SpiceUsbDeviceManagerClass *klas
 
+#ifdef USE_USBREDIR
+
 /* ------------------------------------------------------------------ */
@@ -465,3 +467,2 @@ static void spice_usb_device_manager_class_init(SpiceUsbDeviceManagerClass *klas
 
-#ifdef USE_USBREDIR
 static gboolean spice_usb_device_manager_get_udev_bus_n_address(
@@ -482,3 +483,2 @@ static gboolean spice_usb_device_manager_get_udev_bus_n_address(
 }
-#endif
 
@@ -493,3 +493,2 @@ static void channel_new(SpiceSession *session, SpiceChannel *channel,
     if (SPICE_IS_USBREDIR_CHANNEL(channel)) {
-#ifdef USE_USBREDIR
         spice_usbredir_channel_set_context(SPICE_USBREDIR_CHANNEL(channel),
@@ -497,3 +496,2 @@ static void channel_new(SpiceSession *session, SpiceChannel *channel,
         spice_channel_connect(channel);
-#endif
         g_ptr_array_add(self->priv->channels, channel);
@@ -511,3 +509,2 @@ static void channel_destroy(SpiceSession *session, SpiceChannel *channel,
 
-#ifdef USE_USBREDIR
 static void spice_usb_device_manager_auto_connect_cb(GObject      *gobject,