udev-cache: invalidate on rules.d changes

Presently, the cache is not regenerated if udev rules are modified,
which may cause the cache to preserve an old configuration. To fix,
include the size, mtime, and filename of all udev rules in the system
configuration.

This change requires `stat`. If busybox supplies stat,
CONFIG_FEATURE_STAT_FORMAT must be enabled.

(From OE-Core rev: 8847e33b12171a21b7c7e1241198080ad9ef9284)

Signed-off-by: Richard Tollerton <rich.tollerton@ni.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/meta/recipes-core/udev/udev/udev-cache b/meta/recipes-core/udev/udev/udev-cache
index 4d50876b64..571463fa01 100644
--- a/meta/recipes-core/udev/udev/udev-cache
+++ b/meta/recipes-core/udev/udev/udev-cache
@@ -25,9 +25,14 @@ DEVCACHE_REGEN="/dev/shm/udev-regen" # create to request cache regen
 CMP_FILE_LIST="/proc/version /proc/cmdline /proc/devices"
 [ -f /proc/atags ] && CMP_FILE_LIST="$CMP_FILE_LIST /proc/atags"
 
+# List of files whose metadata (size/mtime/name) will be included in cached
+# system state.
+META_FILE_LIST="lib/udev/rules.d/* etc/udev/rules.d/*"
+
 # Command to compute system configuration.
 sysconf_cmd () {
         cat -- $CMP_FILE_LIST
+        stat -L -c '%s %Y %n' -- $META_FILE_LIST | awk -F/ '{print $1 " " $NF;}'
 }
 
 [ -f /etc/default/udev-cache ] && . /etc/default/udev-cache