Fetch the name and uniq from udev properties, not sysfs (#708)

Both are set by udev based on the sysattr entries anyway and using
the properties instead of the sysfs attr means we can override both via
udev rules should that become necessary.

libwacom/libwacom.c

@@ -214,11 +214,38 @@ client_query_by_subsystem_and_device_file (GUdevClient *client,
 }
 
 static char *
-get_device_uniq(GUdevDevice *device)
+get_device_prop(GUdevDevice *device, const char *propname)
+{
+	char *value = NULL;
+	GUdevDevice *parent = g_object_ref(device);
+
+	do {
+		GUdevDevice *next;
+		const char *v = g_udev_device_get_property(parent, propname);
+		if (v) {
+			/* NAME and UNIQ properties are enclosed with quotes */
+			size_t offset = v[0] == '"' ? 1 : 0;
+			value = g_strdup(v + offset);
+			if (value[strlen(value)] == '"')
+				value[strlen(value)] = '\0';
+			break;
+		}
+		next = g_udev_device_get_parent (parent);
+		g_object_unref(parent);
+		parent = next;
+	} while (parent);
+
+	if (parent)
+		g_object_unref(parent);
+
+	return value;
+}
+
+static char *
+parse_uniq(char *uniq)
 {
 	GRegex *regex;
 	GMatchInfo *match_info;
-	gchar *uniq = g_strdup (g_udev_device_get_sysfs_attr (device, "uniq"));
 
 	if (!uniq)
 		return NULL;
@@ -319,29 +346,10 @@ get_device_info (const char            *path,
 		g_free (sysfs_path);
 	}
 
-	*name = g_strdup (g_udev_device_get_sysfs_attr (device, "name"));
-	*uniq = get_device_uniq (device);
-	/* Try getting the name/uniq from the parent if that fails */
-	if (*name == NULL || *uniq == NULL) {
-		GUdevDevice *parent = g_udev_device_get_parent (device);
-
-		while (parent && (*name == NULL || *uniq == NULL)) {
-			GUdevDevice *old_parent = parent;
-
-			if (*name == NULL)
-				*name = g_strdup (g_udev_device_get_sysfs_attr (parent, "name"));
-			if (*uniq == NULL)
-				*uniq = get_device_uniq (parent);
-			parent = g_udev_device_get_parent (parent);
-			g_object_unref (old_parent);
-		}
-
-		if (parent)
-			g_object_unref (parent);
-
-		if (*name == NULL)
-			goto out;
-	}
+	*name = get_device_prop (device, "NAME");
+	*uniq = parse_uniq(get_device_prop(device, "UNIQ"));
+	if (*name == NULL)
+		goto out;
 
 	/* Parse the PRODUCT attribute (for Bluetooth, USB, I2C) */
 	retval = get_bus_vid_pid (device, bus, vendor_id, product_id, error);