udev: use the usual set of load paths for udev rules

This adds /usr/local/lib/udev/rules.d to the search path on non-split-usr systems.
On split-usr systems, the paths with /usr/-prefixes are added too.
In the past, on split-usr systems, it made sense to only load rules from
/lib/udev/rules.d, because /usr could be mounted late. But we don't support running
without /usr since 80758717a63, so in practice it doesn't matter whether the
rules files are in /lib/udev/rules.d or /usr/lib/udev/rules.d. Distributions
that maintain the illusion of functional split-usr are welcome to simply not put any
files in /usr/lib/udev/rules.d/.

In practice this doesn't change much, but it makes udev more consistent with the
rest of the systemd suite.

diff --git a/man/udev.xml b/man/udev.xml
index 74aab8e..c82a399 100644 (file)
--- a/man/udev.xml
+++ b/man/udev.xml
@@ -45,20 +45,18 @@
   </refsect1>
 
   <refsect1><title>Rules Files</title>
-      <para>The udev rules are read from the files located in the
-      system rules directory <filename>/usr/lib/udev/rules.d</filename>,
-      the volatile runtime directory <filename>/run/udev/rules.d</filename>
-      and the local administration directory <filename>/etc/udev/rules.d</filename>.
-      All rules files are collectively sorted and processed in lexical order,
-      regardless of the directories in which they live. However, files with
-      identical filenames replace each other. Files in <filename>/etc</filename>
-      have the highest priority, files in <filename>/run</filename> take precedence
-      over files with the same name in <filename>/usr/lib</filename>. This can be
-      used to override a system-supplied rules file with a local file if needed;
-      a symlink in <filename>/etc</filename> with the same name as a rules file in
-      <filename>/usr/lib</filename>, pointing to <filename>/dev/null</filename>,
-      disables the rules file entirely. Rule files must have the extension
-      <filename>.rules</filename>; other extensions are ignored.</para>
+      <para>The udev rules are read from the files located in the system rules directories
+      <filename>/usr/lib/udev/rules.d</filename> and <filename>/usr/local/lib/udev/rules.d</filename>, the
+      volatile runtime directory <filename>/run/udev/rules.d</filename> and the local administration
+      directory <filename>/etc/udev/rules.d</filename>.  All rules files are collectively sorted and
+      processed in lexical order, regardless of the directories in which they live. However, files with
+      identical filenames replace each other. Files in <filename>/etc</filename> have the highest priority,
+      files in <filename>/run</filename> take precedence over files with the same name under
+      <filename>/usr</filename>. This can be used to override a system-supplied rules file with a local
+      file if needed; a symlink in <filename>/etc</filename> with the same name as a rules file in
+      <filename>/usr/lib</filename>, pointing to <filename>/dev/null</filename>, disables the rules file
+      entirely. Rule files must have the extension <filename>.rules</filename>; other extensions are
+      ignored.</para>
 
       <para>Every line in the rules file contains at least one key-value pair.
       Except for empty lines or lines beginning with <literal>#</literal>, which are ignored.

diff --git a/src/udev/udev-rules.c b/src/udev/udev-rules.c
index 8603c75..a38853d 100644 (file)
--- a/src/udev/udev-rules.c
+++ b/src/udev/udev-rules.c
@@ -15,6 +15,7 @@
 
 #include "alloc-util.h"
 #include "conf-files.h"
+#include "def.h"
 #include "device-private.h"
 #include "device-util.h"
 #include "dirent-util.h"
@@ -41,6 +42,7 @@
 #include "util.h"
 
 #define PREALLOC_TOKEN          2048
+#define RULES_DIRS (const char* const*) CONF_PATHS_STRV("udev/rules.d")
 
 struct uid_gid {
         unsigned name_off;
@@ -50,13 +52,6 @@ struct uid_gid {
         };
 };
 
-static const char* const rules_dirs[] = {
-        "/etc/udev/rules.d",
-        "/run/udev/rules.d",
-        UDEVLIBEXECDIR "/rules.d",
-        NULL
-};
-
 struct UdevRules {
         usec_t dirs_ts_usec;
         ResolveNameTiming resolve_name_timing;
@@ -1609,7 +1604,7 @@ int udev_rules_new(UdevRules **ret_rules, ResolveNameTiming resolve_name_timing)
 
         udev_rules_check_timestamp(rules);
 
-        r = conf_files_list_strv(&files, ".rules", NULL, 0, rules_dirs);
+        r = conf_files_list_strv(&files, ".rules", NULL, 0, RULES_DIRS);
         if (r < 0)
                 return log_error_errno(r, "Failed to enumerate rules files: %m");
 
@@ -1661,7 +1656,7 @@ bool udev_rules_check_timestamp(UdevRules *rules) {
         if (!rules)
                 return false;
 
-        return paths_check_timestamp(rules_dirs, &rules->dirs_ts_usec, true);
+        return paths_check_timestamp(RULES_DIRS, &rules->dirs_ts_usec, true);
 }
 
 static bool match_key(UdevRules *rules, struct token *token, const char *val) {