[Pkg-nagios-devel] Bug#698137: destroys icinga.cfg on postinst when it's a symlink

[Peter Palfrader]

Package: icinga-common
Version: 1.7.1-4
Severity: serious
Tags: patch

icinga-common's postinst has the following construct:

| cp -a -f "$conffile" "$conffile".tmp
| sed -e ... < "$conffile" > "$conffile.tmp"

In my case, $conffile is a symlink:
} lrwxrwxrwx 1 root root 26 Nov  1 15:11 /etc/icinga/icinga.cfg -> from-git/static/icinga.cfg

so the postinst does effectively sed < $file > $file, and we all know
that this doesn't work and results in $file being empty at the end.

I propose to use sed's -i instead:

(untested)
--- ./icinga-common.postinst	2012-10-01 06:20:10.000000000 +0000
+++ /root/icinga-common.postinst	2013-01-14 10:57:43.751049610 +0000
@@ -65,25 +65,20 @@
 
 		false)
 			check_external_commands=0
 			;;
 	esac
 
-	cp -a -f "$conffile" "$conffile".tmp
-
 	# If the admin deleted or commented some variables but then set
 	# them via debconf, (re-)add them to the config file.
 
 	test -z "$check_external_commands" || \
 	grep -Eq '^ *check_external_commands=' "$conffile" || \
 	echo "check_external_commands=" >> "$conffile"
 
-	sed -e "s|^ *check_external_commands=.*|check_external_commands=$check_external_commands|" \
-	< "$conffile" > "$conffile.tmp"
-
-	mv -f "$conffile".tmp "$conffile"
+	sed -i -e "s|^ *check_external_commands=.*|check_external_commands=$check_external_commands|" "$conffile"
 
 	# Stop a not already stopped icinga instance,
 	# debhelper will start it again automatically at the bottom
 	status="$(/etc/init.d/icinga status >/dev/null 2>&1; echo $?)"
 
 	if [ "$status" -ne 3 ]; then

Cheers,
weasel