[PATCH] upower: Handle Linux power supplies not exporting a present property

[Heiko Stübner]

According to Anton Vorontsov (Linux power supply maintainer) power
supplies should not export a present property when they are not
hotpluggable and users of the properties should handle supplies
without present-property as always present.

This patch implements this feature using an additional
sysfs_file_exists call before sysfs_get_bool.
---
 src/linux/up-device-supply.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/src/linux/up-device-supply.c b/src/linux/up-device-supply.c
index d272e36..9da4861 100644
--- a/src/linux/up-device-supply.c
+++ b/src/linux/up-device-supply.c
@@ -516,7 +516,11 @@ up_device_supply_refresh_battery (UpDeviceSupply *supply)
 	native_path = g_udev_device_get_sysfs_path (native);
 
 	/* have we just been removed? */
-	is_present = sysfs_get_bool (native_path, "present");
+	if (sysfs_file_exists (native_path, "present"))
+		is_present = sysfs_get_bool (native_path, "present");
+	else
+		/* when no present property exists, handle as present */
+		is_present = 1;
 	g_object_set (device, "is-present", is_present, NULL);
 	if (!is_present) {
 		up_device_supply_reset_values (supply);
-- 
1.7.2.3