From 49bfe8921ca27d5b6e36576bc476306cac86757a Mon Sep 17 00:00:00 2001
From: Joanna Rutkowska <joanna@invisiblethingslab.com>
Date: Tue, 2 Aug 2011 14:12:03 +0200
Subject: [PATCH] dom0: qvm-sync-dom0-clock

---
 dom0/qvm-tools/qvm-sync-dom0-clock | 34 ++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 dom0/qvm-tools/qvm-sync-dom0-clock

diff --git a/dom0/qvm-tools/qvm-sync-dom0-clock b/dom0/qvm-tools/qvm-sync-dom0-clock
new file mode 100644
index 00000000..ab588c05
--- /dev/null
+++ b/dom0/qvm-tools/qvm-sync-dom0-clock
@@ -0,0 +1,34 @@
+#!/bin/sh
+
+UPDATES_VM=`qvm-get-updatevm`
+
+QREXEC_CLIENT=/usr/lib/qubes/qrexec_client
+
+if [ -z "$UPDATES_VM" ]; then
+    echo "UpdateVM not set, exiting!" >&2
+    exit 1
+fi
+
+if ! xl domid "$UPDATES_VM" > /dev/null 2>&1; then
+    echo "UpdateVM not started, exiting!"
+    exit 1
+fi
+
+# dd is supposed to not allow memory exhaustion
+# grep does basic sanity checking
+# there seems to be no way to pass output of date +%s.%N to date,
+# so we use human-readable format
+
+CURRENT_TIME="$($QREXEC_CLIENT -d $UPDATES_VM 'user:date -u' |
+	dd count=1 2>/dev/null |
+	grep '^[A-Za-z]* [A-Za-z]* [ 0-9][0-9] [0-9][0-9]:[0-9][0-9]:[0-9][0-9] [A-Z]* [0-9][0-9][0-9][0-9]$'|
+	head -1)"
+
+if [ -n "$CURRENT_TIME" ] ; then 
+	echo Syncing Dom0 clock: setting time "$CURRENT_TIME"...
+	sudo date -u -s "$CURRENT_TIME" ;
+	echo Done.
+else
+	echo "Error while parsing the time obtained from the UpdateVM ($UPDATES_VM).."
+fi
+