Add protection around save, don't go backwards unless forced

Closes: #763589

diff --git a/debian/changelog b/debian/changelog
index ebf72ec..922b294 100644 (file)
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+fake-hwclock (0.8) UNRELEASED; urgency=medium
+
+  * Add protection around save, don't go backwards unless forced.
+    Closes: #763589
+
+ -- Steve McIntyre <93sam@debian.org>  Wed, 01 Oct 2014 12:34:30 +0100
+
 fake-hwclock (0.7) unstable; urgency=medium
 
   * Tweak the systemd bits again.

diff --git a/fake-hwclock b/fake-hwclock
index e9ba7f1..5c34775 100755 (executable)
--- a/fake-hwclock
+++ b/fake-hwclock
@@ -26,7 +26,20 @@ fi
 
 case $COMMAND in
     save)
-        date -u '+%Y-%m-%d %H:%M:%S' > $FILE
+        if [ -e $FILE ] ; then
+            SAVED="$(cat $FILE)"
+            SAVED_SEC=$(date -u -d "$SAVED" '+%s')
+            NOW_SEC=$(date -u '+%s')
+            if $FORCE || [ $NOW_SEC -ge $SAVED_SEC ] ; then
+                date -u '+%Y-%m-%d %H:%M:%S' > $FILE
+            else
+                echo "Current system time: $(date -u '+%Y-%m-%d %H:%M:%S')"
+                echo "fake-hwclock saved clock information is in the future: $SAVED"
+                echo "To force the saved system clock backwards anyway, use \"force\""
+            fi
+        else
+            date -u '+%Y-%m-%d %H:%M:%S' > $FILE
+        fi
         ;;
     load)
         if [ -e $FILE ] ; then

diff --git a/fake-hwclock.8 b/fake-hwclock.8
index b3f14ba..4bafb50 100644 (file)
--- a/fake-hwclock.8
+++ b/fake-hwclock.8
@@ -1,4 +1,4 @@
-.TH FAKE-HWCLOCK 8 "5 April 2012" Debian
+.TH FAKE-HWCLOCK 8 "1 October 2014" Debian
 .SH NAME
 fake-hwclock \- Control fake hardware clock
 .SH SYNOPSIS
@@ -25,7 +25,9 @@ If no command is given then fake-hwclock acts as if the save command was used.
 .SS
 .TP
 \fBsave\fP
-Save the time to the file.
+Save the time to the file. If force is specified fake-hwclock will move the
+saved clock either backwards or forwards. Otherwise it will only move
+it forwards.
 .TP
 \fBload\fP
 Load the time from the file. If force is specified fake-hwclock will move the