Updated recovery scripts for recovery 19.07.8

The recovery scripts have been rewritten for the new recovery 19.07.8.
Besides the capability to mount/unmount the main firmware image, it is now
possible to reset the main to defaults.
To facilitate the unlocking of the MTD partitions a new script was also
included as the interface to the mtd-rw kernel module.

Signed-off-by: Bruno Pena <[email protected]>

mount-firmware

@@ -0,0 +1,79 @@
+#!/bin/sh
+
+# check if firmware is already mounted
+if egrep -qs "^overlayfs:/firmware " /proc/mounts; then
+ echo "firmware is already mounted">&2
+ exit 1
+fi
+
+# find firmware mtd partition
+firmware=$(grep '"firmware"' /proc/mtd | cut -d: -f1)
+firmware_size=$(cat /sys/class/mtd/${firmware}/size)
+firmware_blocksize=$(cat /sys/class/mtd/${firmware}/erasesize)
+
+# setup filesystem markers (rootfs: squashfs, rootfs_data: jffs2)
+rootfs_marker="6873"
+rootfsdata_marker="(deadc0de|1985)"
+
+# search for the rootfs filesystem offset within the firmware mtd partition
+rootfs_offset=0
+while [ ${rootfs_offset} -lt ${firmware_size} ]; do
+ # dump four bytes at offset (as hexadecimal string) and check if matches the marker pattern
+ if hexdump -e '"%x"' -n 4 -s ${rootfs_offset} /dev/${firmware} | egrep -qs "^${rootfs_marker}"; then
+ # marker found, break loop
+ break
+ fi
+ # continue searching, move to the next mtd block
+ rootfs_offset=$((rootfs_offset + firmware_blocksize))
+done
+
+# search for the rootfs_data filesystem offset within the firmware mtd partition
+rootfsdata_offset=$((rootfs_offset + firmware_blocksize))
+while [ ${rootfsdata_offset} -lt ${firmware_size} ]; do
+ # dump four bytes at offset (as hexadecimal string) and check if matches the marker pattern
+ if hexdump -e '"%x"' -n 4 -s ${rootfsdata_offset} /dev/${firmware} | egrep -qs "^${rootfsdata_marker}"; then
+ # marker found, break loop
+ break
+ fi
+ # continue searching, move to the next mtd block
+ rootfsdata_offset=$((rootfsdata_offset + firmware_blocksize))
+done
+
+# calculate filesystem sizes
+rootfs_size=$((rootfsdata_offset - rootfs_offset))
+rootfsdata_size=$((firmware_size - rootfsdata_offset))
+
+# create loop device for each filesystem (virtual "partition" delimited by offset and size)
+rootfs_loop=$(losetup --offset ${rootfs_offset} --sizelimit ${rootfs_size} -f --show /dev/mtdblock${firmware:3})
+rootfsdata_loop=$(losetup --offset ${rootfsdata_offset} --sizelimit ${rootfsdata_size} -f --show /dev/mtdblock${firmware:3})
+
+# create virtual mtd for the loop devices
+modprobe -q block2mtd
+echo "${rootfs_loop},${firmware_blocksize}" > /sys/module/block2mtd/parameters/block2mtd
+echo "${rootfsdata_loop},${firmware_blocksize}" > /sys/module/block2mtd/parameters/block2mtd
+
+# search for the newly created mtd names
+rootfs=$(grep '"'${rootfs_loop}'"' /proc/mtd | cut -d: -f1)
+rootfsdata=$(grep '"'${rootfsdata_loop}'"' /proc/mtd | cut -d: -f1)
+
+# create mountpoint if needed
+[ ! -d /firmware ] && mkdir /firmware
+
+# mount filesystems (rootfs and rootfs_data)
+mount -t squashfs /dev/mtdblock${rootfs:3} /firmware
+mount -t jffs2 -o noatime /dev/mtdblock${rootfsdata:3} /firmware/overlay
+
+# initialize rootfs_data
+[ ! -d /firmware/overlay/upper ] && mkdir /firmware/overlay/upper
+[ ! -d /firmware/overlay/work ] && mkdir /firmware/overlay/work
+[ ! -h /firmware/overlay/.fs_state ] && ln -s 2 /firmware/overlay/.fs_state
+
+# create rootfs_data overlay at /mnt
+mount -t overlay -o noatime,lowerdir=/firmware,upperdir=/firmware/overlay/upper,workdir=/firmware/overlay/work overlayfs:/firmware /mnt
+
+# combine all mountpoints on /mnt
+mount --move /firmware/overlay /mnt/overlay
+mount --move /firmware /mnt/rom
+
+# finally, move the result to /firmware
+mount --move /mnt /firmware

mtd-rw

@@ -0,0 +1,25 @@
+#!/bin/sh
+
+case "$1" in
+ lock) # lock all mtd partitions
+ "$0" unlocked && rmmod mtd-rw
+ ;;
+
+ unlock) # unlock all mtd partitions
+ "$0" locked && insmod "$(find /lib/modules/ -name mtd-rw.ko)" i_want_a_brick=1
+ ;;
+
+ locked) # check if mtd partitions are locked
+ ! "$0" unlocked
+ ;;
+
+ unlocked) # check if mtd partitions are unlocked
+ lsmod | egrep -qs "^mtd_rw "
+ ;;
+
+ *) # usage help message
+ echo "Usage: $(basename $0) <lock|unlock|locked|unlocked>"
+ ;;
+esac
+
+exit $?

recovery-config

@@ -0,0 +1,37 @@
+#!/bin/sh
+
+# check if script arguments are valid
+if [ "$1" != "save" -a "$1" != "reset" ]; then
+ # display usage message in case of insufficient or invalid arguments
+ echo "Usage: $(basename $0) <save|reset>"
+ exit 1
+fi
+
+# check mtd state and unlock if needed
+if mtd-rw locked; then
+ mtd-rw unlock
+ relock=1
+fi
+
+# check whether to save or reset the current configuration
+if [ "$1" == "save" ]; then
+ # create archive of the current configuration
+ tar czf /tmp/config.tar.gz -C /volatile/upper $(ls /volatile/upper/)
+else
+ # create an empty configuration archive
+ dd if=/dev/zero bs=10240 count=1 2>/dev/null | gzip > /tmp/config.tar.gz
+fi
+
+# store the configuration archive to mtd
+snapshot_tool config_write &>/dev/null
+if [ "$?" != "0" ]; then
+ echo "operation failed"
+fi
+
+# clean up configuration archive
+rm -f /tmp/config.tar.gz
+
+# lock mtd if it was unlocked by this script
+if [ "${relock}" == "1" ]; then
+ mtd-rw lock
+fi

reset-firmware

@@ -0,0 +1,42 @@
+#!/bin/sh
+
+# display warn message, wait for user confirmation before continuing
+echo -n "erase all settings and remove any installed packages? [N/y] ">&2 && read
+[ "${REPLY}" != "y" ] && exit 1
+
+# check firmware mount state to then delete data accordingly
+if egrep -qs "^overlayfs:/firmware " /proc/mounts; then
+ # inform user about firmware mount state and action taken to reset rootfs_data
+ echo "firmware is mounted, only erasing files">&2
+
+ # erase all files (including "dot" and "dot-dot" files)
+ rm -rf /firmware/overlay/upper/*
+ rm -rf /firmware/overlay/upper/.[^.]*
+ rm -rf /firmware/overlay/upper/..?*
+else
+ # inform user about firmware mount state and action taken to reset rootfs_data
+ echo "firmware not mounted, marking it to be erased on next mount">&2
+
+ # find firmware mtd partition
+ firmware=$(grep '"firmware"' /proc/mtd | cut -d: -f1)
+ firmware_size=$(cat /sys/class/mtd/${firmware}/size)
+ firmware_blocksize=$(cat /sys/class/mtd/${firmware}/erasesize)
+
+ # initialize rootfs_data search variables
+ rootfsdata_marker="(deadc0de|1985)"
+ rootfsdata_offset=0
+
+ # search for rootfs_data inside firmware mtd partition
+ while [ ${rootfsdata_offset} -lt ${firmware_size} ]; do
+ # dump four bytes at offset (as hexadecimal string) and check if matches the marker pattern
+ if hexdump -e '"%x"' -n 4 -s ${rootfsdata_offset} /dev/${firmware} | egrep -qs "^${rootfsdata_marker}"; then
+ # marker found, break loop
+ break
+ fi
+ # continue searching, move to the next mtd block
+ rootfsdata_offset=$((rootfsdata_offset + firmware_blocksize))
+ done
+
+ # write jffs2 marker (0xdeadc0de) to force initialization of rootfs_data on the next mount
+ echo -ne "\xde\xad\xc0\xde" | dd of=/dev/mtdblock${firmware:3} bs=${firmware_blocksize} seek=$((rootfsdata_offset / firmware_blocksize)) count=1 conv=sync &>/dev/null
+fi

umount-firmware

@@ -0,0 +1,27 @@
+#!/bin/sh
+
+# check if firmware is mounted
+if ! egrep -qs "^overlayfs:/firmware " /proc/mounts; then
+ echo "firmware is not mounted">&2
+ exit 1
+fi
+
+# search /proc/mounts for firmware's virtual mtd devices
+rootfs=$(grep " /firmware/rom " /proc/mounts | cut -d" " -f1 | cut -d/ -f3 | sed 's/block//')
+rootfsdata=$(grep " /firmware/overlay " /proc/mounts | cut -d" " -f1 | cut -d/ -f3 | sed 's/block//')
+
+# map the virtual mtd devices to the corresponding loop devices
+rootfs_loop=$(egrep "^${rootfs}:" /proc/mtd | cut -d\" -f2)
+rootfsdata_loop=$(egrep "^${rootfsdata}:" /proc/mtd | cut -d\" -f2)
+
+# umount all mountpoints
+umount /firmware/overlay
+umount /firmware/rom
+umount /firmware
+
+# remove virtual mtd devices (only possible by unloading the block2mtd kernel module)
+rmmod block2mtd
+
+# remove the corresponding loop devices
+losetup -d ${rootfs_loop}
+losetup -d ${rootfsdata_loop}