linux: Do not rely on parent ID lookup to work at removal time

It appears that the parent ID lookup may not properly work when devices
are removed. Likely, because corresponding sysfs entries may not exist
anymore.

Fix this by attaching the ID to the stored object, allowing us to remove
it without calling device_parent_id() again.

Fixes: #185

1 files changed, 20 insertions, 13 deletions

diff --git a/src/linux/up-enumerator-udev.c b/src/linux/up-enumerator-udev.c
index a230308..917747a 100644
--- a/src/linux/up-enumerator-udev.c
+++ b/src/linux/up-enumerator-udev.c
@@ -181,15 +181,14 @@ uevent_signal_handler_cb (UpEnumeratorUdev *self,
 			parent_id = device_parent_id (device);
 			g_debug ("device %s has parent id: %s", device_key, parent_id);
 			if (parent_id) {
-				gboolean insert = FALSE;
-				GPtrArray *devices;
+				GPtrArray *devices = NULL;
+				char *parent_id_key = NULL;
 				int i;
 
-				devices = g_hash_table_lookup (self->siblings, parent_id);
-				if (!devices) {
-					insert = TRUE;
+				g_hash_table_lookup_extended (self->siblings, parent_id,
+				                              (gpointer*)&parent_id_key, (gpointer*)&devices);
+				if (!devices)
 					devices = g_ptr_array_new_with_free_func (g_object_unref);
-				}
 
 				for (i = 0; i < devices->len; i++) {
 					GObject *sibling = g_ptr_array_index (devices, i);
@@ -201,8 +200,13 @@ uevent_signal_handler_cb (UpEnumeratorUdev *self,
 				}
 
 				g_ptr_array_add (devices, g_object_ref (obj));
-				if (insert)
-					g_hash_table_insert (self->siblings, g_strdup (parent_id), devices);
+				if (!parent_id_key) {
+					parent_id_key = g_strdup (parent_id);
+					g_hash_table_insert (self->siblings, parent_id_key, devices);
+				}
+
+				/* Just a reference to the hash table key */
+				g_object_set_data (obj, "udev-parent-id", parent_id_key);
 			}
 
 			if (up_dev)
@@ -221,14 +225,17 @@ uevent_signal_handler_cb (UpEnumeratorUdev *self,
 		g_autoptr(GObject) obj = NULL;
 		const char *key = NULL;
 
-		g_debug ("removing device for path %s", g_udev_device_get_sysfs_path (device));
 		g_hash_table_steal_extended (self->known, device_key,
 		                             (gpointer*) &key, (gpointer*) &obj);
 
 		if (obj) {
-			g_autofree char *parent_id = device_parent_id (device);
+			char *parent_id;
+
+			g_debug ("removing device for path %s", g_udev_device_get_sysfs_path (device));
+
+			parent_id = g_object_get_data (obj, "udev-parent-id");
 
-			/* Remove from siblings table */
+			/* Remove from siblings table. */
 			if (parent_id) {
 				GPtrArray *devices;
 
@@ -244,8 +251,8 @@ uevent_signal_handler_cb (UpEnumeratorUdev *self,
 
 		if (obj && UP_IS_DEVICE (obj)) {
 			g_signal_emit_by_name (self, "device-removed", obj);
-		} else
-			g_debug ("ignoring remove event on %s", g_udev_device_get_sysfs_path (device));
+		} else if (!obj)
+			g_debug ("ignored remove event on %s", g_udev_device_get_sysfs_path (device));
 	}
 }