udev: fix uevent-helper disable

Make sure that /proc/sys/kernel/hotplug exists before trying to disable the uevent-helper mechanism.

Since kernel commit 86d56134f1b6 ("kobject: Make support for uevent_helper optional.") the kernel can be built without uevent-helper support. In this case /proc/sys/kernel/hotplug does not exist and the current sysvinit script fails with

/etc/rcS.d/S04udev: line 132: can't create /proc/sys/kernel/hotplug: nonexistent directory

when trying to disable the uevent-helper mechanism during boot.

Note that a single NULL-character has always been sufficient to disable.

---

Patch is against daisy-11.0.1 but should apply fine to master. All branches affected.

Thanks,
Johan

 meta/recipes-core/udev/udev/init | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 410a650bd192..63e59d3950c9 100644
@@ -97,7 +97,7 @@ case "$1" in
     kill_udevd > "/dev/null" 2>&1
 
     # trigger the sorted events
-    echo -e '\000\000\000\000' > /proc/sys/kernel/hotplug
+    [ -e /proc/sys/kernel/hotplug ] && echo -e '\000' >/proc/sys/kernel/hotplug
     @UDEVD@ -d
 
     udevadm control --env=STARTUP=1

2.0.4