base-files: sysupgrade: do not rely on opkg to list changed conffiles

Many packages use the opkg conffiles field to list configuration files that
are to be retained on upgrades. Make this work on systems without opkg.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>

1 files changed, 20 insertions, 1 deletions

diff --git a/package/base-files/files/sbin/sysupgrade b/package/base-files/files/sbin/sysupgrade
index c747c4eaad..bf5428af25 100755
--- a/package/base-files/files/sbin/sysupgrade
+++ b/package/base-files/files/sbin/sysupgrade
@@ -96,12 +96,31 @@ EOF
 # prevent messages from clobbering the tarball when using stdout
 [ "$CONF_BACKUP" = "-" ] && export VERBOSE=0
 
+
+list_conffiles() {
+	awk '
+		BEGIN { conffiles = 0 }
+		/^Conffiles:/ { conffiles = 1; next }
+		!/^ / { conffiles = 0; next }
+		conffiles == 1 { print }
+	' /usr/lib/opkg/status
+}
+
+list_changed_conffiles() {
+	# Cannot handle spaces in filenames - but opkg cannot either...
+	list_conffiles | while read file csum; do
+		[ -r "$file" ] || continue
+
+		echo "${csum}  ${file}" | sha256sum -sc - || echo "$file"
+	done
+}
+
 add_uci_conffiles() {
 	local file="$1"
 	( find $(sed -ne '/^[[:space:]]*$/d; /^#/d; p' \
 		/etc/sysupgrade.conf /lib/upgrade/keep.d/* 2>/dev/null) \
 		-type f -o -type l 2>/dev/null;
-	  opkg list-changed-conffiles ) | sort -u > "$file"
+	  list_changed_conffiles ) | sort -u > "$file"
 	return 0
 }