On Sun, 30 Jul 2006, Hubert Feyrer wrote:
> I think /etc/security's backup_and_diff() invoked on every time
> /etc/rc.d/dmesg gets ran (with secibd arument set to "no" to not print
> the diff) sounds pretty easy. The function needs to get migrated to
> rc.subr, though.

My /etc/rc.d/dmesg has been backing up to RCS for several years (using
backup_file from /etc/rc.subr).  Last time I mentioned this, people
thought that it was pointless.  If that opinion has changed, I'd be
happy to get my patches into a state where they can be committed.

Working but ugly patch appended.

--apb (Alan Barrett)

--- rc.d/dmesg	(NetBSD: dmesg,v 1.9 2004/08/13 18:08:03)
+++ rc.d/dmesg	2005-08-08 13:10:58.000000000 +0200
@@ -12,13 +12,49 @@
 name="dmesg"
 rcvar=$name
 dmesg_file="/var/run/dmesg.boot"
+backup_dir="${backup_dir:-/var/backups}"
+#work_dir="${backup_dir}/work"
+work_dir="${backup_dir}/${dmesg_file%/*}"
 start_cmd="do_dmesg"
 stop_cmd=":"
 
 do_dmesg()
 {
+	set -x
+	mkdir -p ${work_dir}
+	BASE=${dmesg_file##*/}
+	CUR=${work_dir}/${BASE}.current
+	BACK=${work_dir}/${BASE}.backup
+	#echo "start"
+	#ls -ld ${dmesg_file} ${CUR} ${CUR},v
+	# Backup the old file left over from the previous boot,
+	# if it was not already backed up.
+	if [ -f ${dmesg_file} ]; then
+		if [ -f $CUR ] && cmp -s ${dmesg_file} $CUR; then
+		    : OK
+		else
+		    echo "Backing up old ${dmesg_file} from previous boot."
+		    backup_file update ${dmesg_file} $CUR $BACK
+		fi
+	fi
+	#echo "saved old"
+	#ls -ld ${dmesg_file} ${CUR} ${CUR},v
+	# Create the new file.
 	rm -f ${dmesg_file}
 	( umask 022 ; /sbin/dmesg $rc_flags > ${dmesg_file} )
+	#echo "new"
+	#ls -ld ${dmesg_file} ${CUR} ${CUR},v
+	# Backup the new file, if it has changed.
+	if [ -f $CUR ] && cmp -s ${dmesg_file} $CUR; then
+	    : No changes
+	    echo "Not backing up unchanged ${dmesg_file}"
+	else
+	    #diff -u2 ${CUR} ${dmesg_file}
+	    echo "Backing up new ${dmesg_file}"
+	    backup_file update ${dmesg_file} $CUR $BACK
+	fi
+	#echo "end"
+	#ls -ld ${dmesg_file} ${CUR} ${CUR},v
 }
 
 load_rc_config $name