From 05b0d8c81b59c077b49f1b9215edba154d4f015a Mon Sep 17 00:00:00 2001
From: CyberLeo <cyberleo@cyberleo.net>
Date: Sat, 13 Feb 2010 09:42:46 -0600
Subject: [PATCH] overlay/sbin/saveconfig: Stage config in temp area, for
 atomic swap

---
 overlay/sbin/saveconfig | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/overlay/sbin/saveconfig b/overlay/sbin/saveconfig
index fc3cab3..3770956 100755
--- a/overlay/sbin/saveconfig
+++ b/overlay/sbin/saveconfig
@@ -8,14 +8,22 @@ then
     exit 1
 fi
 
+# Find all files newer than /etc/diskless and print them out
 find_newer_files() {
   [ -d "${1}" ] || return 1
   find "${1}" -type f -not -regex '.*/tmp/*.' -newer /etc/diskless -print
 }
 
-archive() {
+# Archive all newer files into a gzipped cpio archive
+archive_cpio() {
   [ -d "${1}" ] || return 1
-  find_newer_files "${1}" | cpio -o | gzip -9 > "/conf/default/${1}.cpio.gz"
+  [ -f "${2}" ] && return 1
+  find_newer_files "${1}" | cpio -o | gzip -9 > "${2}"
+}
+
+# Archive specified files to named target
+archive() {
+  archive_cpio "${1}" "${2}.cpio.gz"
 }
 
 # Mount /conf read-write, and remount if it already is.
@@ -30,19 +38,18 @@ then
         fi
 fi
 
+# Store config in temp staging area
+mkdir -p /conf/tmp || exit 1
+archive /etc /conf/tmp/etc || exit 1
+archive /var /conf/tmp/var || exit 1
 
+# Rotate current config to dated backup
 # Unlimited history method: (make sure you have provisions for removing the old backups, or this can get HUGE!
 dest="$(date -r "$(stat -f '%c' "/conf/default")" "+%Y-%m-%dT%H-%M-%S")"
-mv /conf/default "/conf/backup/${dest}"
-
-mkdir /conf/default
+mv /conf/default "/conf/backup/${dest}" || exit 1
 
-cd /
-# Copy changed config files to /conf/default (anything younger than /etc/diskless)
-#find etc var -type f -not -regex '.*/tmp/.*' -newer /etc/diskless -print0 | cpio -p /conf/default/
-# This can be changed to allow compressed configuration here as well:
-archive etc
-archive var
+# Move temp config to current
+mv /conf/tmp /conf/default || mv "/conf/backup/${dest}" "/conf/default"
 
 # Umount /conf afterwards, if it wasn't mounted
 if [ -z "${_was_mounted}" -a "$(mount |grep -c "/conf")" -gt 0 ]
-- 
2.42.0