ignore duplicated rules file names

2 files changed, 24 insertions, 7 deletions

diff --git a/udev/udev.xml b/udev/udev.xml
index c740c0d807..51e2fdc84e 100644
--- a/udev/udev.xml
+++ b/udev/udev.xml
@@ -74,8 +74,15 @@
           the custom rules directory <filename>/etc/udev/rules.d/</filename>
           and the temporary rules directory <filename>/dev/.udev/rules.d/</filename>.
           All rule files are sorted and processed in lexical order, regardless
-          in which of these directories they live. Every line in the rules file contains at least
-          one key value pair. There are two kind of keys, match and assignment keys.
+          in which of these directories they live.</para>
+
+          <para>Rule files are required to have a unique name, duplicate file names
+          are ignored. Files in <filename>/etc/udev/rules.d/</filename> have precedence
+          over files with the same name in <filename>/lib/udev/rules.d/</filename>. This
+          can be used to ignore a default rules file if needed.</para>
+
+          <para>Every line in the rules file contains at least one key value pair.
+          There are two kind of keys, match and assignment keys.
           If all match keys are matching against its value, the rule gets applied and the
           assign keys get the specified value assigned.</para>
 
diff --git a/udev/udev_rules_parse.c b/udev/udev_rules_parse.c
index 273f92f486..bf833bae54 100644
--- a/udev/udev_rules_parse.c
+++ b/udev/udev_rules_parse.c
@@ -741,11 +741,8 @@ int udev_rules_init(struct udev_rules *rules, int resolve_names)
 		/* custom rules location for testing */
 		add_matching_files(&name_list, udev_rules_dir, ".rules");
 	} else {
-		/* read default rules */
-		add_matching_files(&name_list, UDEV_PREFIX "/lib/udev/rules.d", ".rules");
-
 		/* read user/custom rules */
-		add_matching_files(&sort_list, SYSCONFDIR "/udev/rules.d", ".rules");
+		add_matching_files(&name_list, SYSCONFDIR "/udev/rules.d", ".rules");
 
 		/* read dynamic/temporary rules */
 		strlcpy(filename, udev_root, sizeof(filename));
@@ -758,6 +755,9 @@ int udev_rules_init(struct udev_rules *rules, int resolve_names)
 		}
 		add_matching_files(&sort_list, filename, ".rules");
 
+		/* read default rules */
+		add_matching_files(&sort_list, UDEV_PREFIX "/lib/udev/rules.d", ".rules");
+
 		/* sort all rules files by basename into list of files */
 		list_for_each_entry_safe(sort_loop, sort_tmp, &sort_list, node) {
 			const char *sort_base = strrchr(sort_loop->name, '/');
@@ -771,10 +771,20 @@ int udev_rules_init(struct udev_rules *rules, int resolve_names)
 				if (name_base == NULL)
 					continue;
 
+				if (strcmp(name_base, sort_base) == 0) {
+					info("rule file '%s' already added, ignoring '%s'\n",
+					     name_loop->name, sort_loop->name);
+					list_del(&sort_loop->node);
+					free(sort_loop);
+					sort_loop = NULL;
+					continue;
+				}
+
 				if (strcmp(name_base, sort_base) > 0)
 					break;
 			}
-			list_move_tail(&sort_loop->node, &name_loop->node);
+			if (sort_loop != NULL)
+				list_move_tail(&sort_loop->node, &name_loop->node);
 		}
 	}