From 138ef72fbc2264a341873c1cf8c771c1c143922a Mon Sep 17 00:00:00 2001
From: Kay Sievers <kay@vrfy.org>
Date: Wed, 4 Sep 2013 17:59:14 +0200
Subject: [PATCH] libudev: enumerate - do not try to match against an empty
 subsystem

---
 src/libudev/libudev-enumerate.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/libudev/libudev-enumerate.c b/src/libudev/libudev-enumerate.c
index 385829d..bc1e37d 100644
--- a/src/libudev/libudev-enumerate.c
+++ b/src/libudev/libudev-enumerate.c
@@ -721,12 +721,14 @@ static bool match_subsystem(struct udev_enumerate *udev_enumerate, const char *s
 {
         struct udev_list_entry *list_entry;
 
-        subsystem = subsystem ? : "";
+        if (!subsystem)
+                return false;
 
         udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->subsystem_nomatch_list)) {
                 if (fnmatch(udev_list_entry_get_name(list_entry), subsystem, 0) == 0)
                         return false;
         }
+
         if (udev_list_get_entry(&udev_enumerate->subsystem_match_list) != NULL) {
                 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->subsystem_match_list)) {
                         if (fnmatch(udev_list_entry_get_name(list_entry), subsystem, 0) == 0)
@@ -734,6 +736,7 @@ static bool match_subsystem(struct udev_enumerate *udev_enumerate, const char *s
                 }
                 return false;
         }
+
         return true;
 }