base-files: add sysupgrade -u to skip unchanged files

With '-u', for a file /aaa/bbb/ccc enlisted for backup,
it will only get into backup if /rom/aaa/bbb/ccc does not
exist or /aaa/bbb/ccc is different from /rom/aaa/bbb/ccc.

It also works with '-c', but only effective for files touched
but not modified.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>

diff --git a/package/base-files/files/sbin/sysupgrade b/package/base-files/files/sbin/sysupgrade
index 4ea8be518a70e3583b0179d81cc5eec684f3b264..d4bb7a164fe3b139e8a6481011990cab1ffbc40a 100755 (executable)
--- a/package/base-files/files/sbin/sysupgrade
+++ b/package/base-files/files/sbin/sysupgrade
@@ -10,6 +10,7 @@ export VERBOSE=1
 export SAVE_CONFIG=1
 export SAVE_OVERLAY=0
 export SAVE_PARTITIONS=1
+export SKIP_UNCHANGED=0
 export CONF_IMAGE=
 export CONF_BACKUP_LIST=0
 export CONF_BACKUP=
@@ -28,6 +29,7 @@ while [ -n "$1" ]; do
                -n) export SAVE_CONFIG=0;;
                -c) export SAVE_OVERLAY=1;;
                -p) export SAVE_PARTITIONS=0;;
+               -u) export SKIP_UNCHANGED=1;;
                -b|--create-backup) export CONF_BACKUP="$2" NEED_IMAGE=1; shift;;
                -r|--restore-backup) export CONF_RESTORE="$2" NEED_IMAGE=1; shift;;
                -l|--list-backup) export CONF_BACKUP_LIST=1;;
@@ -52,12 +54,13 @@ IMAGE="$1"
 [ -z "$IMAGE" -a -z "$NEED_IMAGE" -a $CONF_BACKUP_LIST -eq 0 -o $HELP -gt 0 ] && {
        cat <<EOF
 Usage: $0 [<upgrade-option>...] <image file or URL>
-       $0 [-q] [-i] [-c] <backup-command> <file>
+       $0 [-q] [-i] [-c] [-u] <backup-command> <file>
 
 upgrade-option:
        -f <config>  restore configuration from .tar.gz (file or url)
        -i           interactive mode
        -c           attempt to preserve all changed files in /etc/
+       -u           skip from backup files that are equal to those in /rom
        -n           do not save configuration over reflash
        -p           do not attempt to restore the partition table after flash.
        -T | --test
@@ -119,20 +122,19 @@ add_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;
+               \( -type f -o -type l \) $find_filter 2>/dev/null;
          list_changed_conffiles ) | sort -u > "$file"
        return 0
 }
 
 add_overlayfiles() {
        local file="$1"
-       find /overlay/upper/etc/ -type f -o -type l | sed \
-               -e 's,^/overlay\/upper/,/,' \
-               -e '\,/META_[a-zA-Z0-9]*$,d' \
-               -e '\,/functions.sh$,d' \
+       ( cd /overlay/upper/; find ./etc \( -type f -o -type l \) $find_filter | sed \
+               -e 's,^\.,,' \
+               -e '\,^/etc/board.json$,d' \
                -e '\,/[^/]*-opkg$,d' \
-               -e '\,/etc/urandom.seed$,d' \
-       > "$file"
+               -e '\,^/etc/urandom.seed$,d' \
+       )> "$file"
        return 0
 }
 
@@ -149,6 +151,15 @@ else
        sysupgrade_init_conffiles="add_conffiles"
 fi
 
+find_filter=""
+if [ $SKIP_UNCHANGED = 1 ]; then
+       [ ! -d /rom/ ] && {
+               echo "'/rom/' is required by '-u'"
+               exit 1
+       }
+       find_filter='( ( -exec test -e /rom/{} ; -exec cmp -s /{} /rom/{} ; ) -o -print )'
+fi
+
 include /lib/upgrade
 
 do_save_conffiles() {