[PATCH] hotplug: update xencommons script to run only when needed

[Olaf Hering <olaf@aepfle.de>]

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1313133097 -7200
# Node ID 0e95f2c754bf526a89bb8a097959e6c970e9b5b7
# Parent  1f08b380d4386cdd6714786a9163e5f51aecab5d
hotplug: update xencommons script to run only when needed

Currently xencommons prints an error if /proc/xen/capabilities does not
exist when started on a non-xen kernel.

Update the xencommons script to run only when needed:
- do not run if /proc/xen does not exist
- check if /proc/xen/capabilities exists before doing the grep for dom0
- use variable for /proc/xen/capabilities
- use grep -q instead of stdout redirection when looking for xenfs,
  its already used later

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r 1f08b380d438 -r 0e95f2c754bf tools/hotplug/Linux/init.d/xencommons
--- a/tools/hotplug/Linux/init.d/xencommons
+++ b/tools/hotplug/Linux/init.d/xencommons
@@ -27,17 +27,29 @@ fi
 test -f $xencommons_config/xencommons && . $xencommons_config/xencommons
 
 XENCONSOLED_PIDFILE=/var/run/xenconsoled.pid
+XEN_CAPABILITIES=/proc/xen/capabilities
 shopt -s extglob
 
+# not running in Xen dom0 or domU
+if ! test -d /proc/xen ; then
+	exit 0
+fi
+
+# mount xenfs in dom0 or domU with a pv_ops kernel
 if test "x$1" = xstart && \
-     test -d /proc/xen && \
-   ! test -f /proc/xen/capabilities && \
-   ! grep '^xenfs ' /proc/mounts >/dev/null;
+   ! test -f $XEN_CAPABILITIES && \
+   ! grep -q '^xenfs ' /proc/mounts ;
 then
 	mount -t xenfs xenfs /proc/xen
 fi
 
-if ! grep -q "control_d" /proc/xen/capabilities ; then
+# run this script only in dom0:
+# no capabilities file in xenlinux kernel
+if ! test -f $XEN_CAPABILITIES ; then
+	exit 0
+fi
+# empty capabilities file in pv_ops kernel
+if ! grep -q "control_d" $XEN_CAPABILITIES ; then
 	exit 0
 fi