#!/bin/sh

. /lib/functions.sh
. /lib/functions/system.sh

export IMAGE="$1"
COMMAND="$2"

export ARGV="$IMAGE"
export ARGC=1

export SAVE_CONFIG=1
export SAVE_PARTITIONS=1

export INTERACTIVE=0
export VERBOSE=1
export CONFFILES=/tmp/sysupgrade.conffiles
export CONF_TAR=/tmp/sysupgrade.tgz

RAMFS_COPY_BIN=		# extra programs for temporary ramfs root
RAMFS_COPY_DATA=	# extra data files


[ -f "$CONF_TAR" ] || export SAVE_CONFIG=0
[ -f /tmp/sysupgrade.always.overwrite.bootdisk.partmap ] && export SAVE_PARTITIONS=0

include /lib/upgrade


supivot() { # <new_root> <old_root>
	/bin/mount | grep "on $1 type" 2>&- 1>&- || /bin/mount -o bind $1 $1
	mkdir -p $1$2 $1/proc $1/sys $1/dev $1/tmp $1/overlay && \
	/bin/mount -o noatime,move /proc $1/proc && \
	pivot_root $1 $1$2 || {
		/bin/umount -l $1 $1
		return 1
	}

	/bin/mount -o noatime,move $2/sys /sys
	/bin/mount -o noatime,move $2/dev /dev
	/bin/mount -o noatime,move $2/tmp /tmp
	/bin/mount -o noatime,move $2/overlay /overlay 2>&-
	return 0
}

switch_to_ramfs() {
	for binary in \
		/bin/busybox /bin/ash /bin/sh /bin/mount /bin/umount	\
		pivot_root mount_root reboot sync kill sleep		\
		md5sum hexdump cat zcat bzcat dd tar			\
		ls basename find cp mv rm mkdir rmdir mknod touch chmod \
		'[' printf wc grep awk sed cut				\
		mtd partx losetup mkfs.ext4				\
		ubiupdatevol ubiattach ubiblock ubiformat		\
		ubidetach ubirsvol ubirmvol ubimkvol			\
		snapshot snapshot_tool					\
		$RAMFS_COPY_BIN
	do
		local file="$(which "$binary" 2>/dev/null)"
		[ -n "$file" ] && install_bin "$file"
	done
	install_file /etc/resolv.conf /lib/*.sh /lib/functions/*.sh /lib/upgrade/*.sh $RAMFS_COPY_DATA

	[ -L "/lib64" ] && ln -s /lib $RAM_ROOT/lib64

	supivot $RAM_ROOT /mnt || {
		echo "Failed to switch over to ramfs. Please reboot."
		exit 1
	}

	/bin/mount -o remount,ro /mnt
	/bin/umount -l /mnt

	grep /overlay /proc/mounts > /dev/null && {
		/bin/mount -o noatime,remount,ro /overlay
		/bin/umount -l /overlay
	}
}

kill_remaining() { # [ <signal> [ <loop> ] ]
	local loop_limit=10

	local sig="${1:-TERM}"
	local loop="${2:-0}"
	local run=true
	local stat

	echo -n "Sending $sig to remaining processes ... "

	while $run; do
		run=false
		for stat in /proc/[0-9]*/stat; do
			[ -f "$stat" ] || continue

			local pid name state ppid rest
			read pid name state ppid rest < $stat
			name="${name#(}"; name="${name%)}"

			# Skip PID1, ourself and our children
			[ $pid -ne 1 -a $pid -ne $$ -a $ppid -ne $$ ] || continue

			local cmdline
			read cmdline < /proc/$pid/cmdline

			# Skip kernel threads
			[ -n "$cmdline" ] || continue

			echo -n "$name "
			kill -$sig $pid 2>/dev/null

			[ $loop -eq 1 ] && run=true
		done

		let loop_limit--
		[ $loop_limit -eq 0 ] && {
			echo
			echo "Failed to kill all processes."
			exit 1
		}
	done
	echo
}


killall -9 telnetd
killall -9 dropbear
killall -9 ash

kill_remaining TERM
sleep 3
kill_remaining KILL 1

sleep 1


if [ -n "$IMAGE" ] && type 'platform_pre_upgrade' >/dev/null 2>/dev/null; then
	IS_PRE_UPGRADE=1 platform_pre_upgrade "$IMAGE"

	# Needs to be unset again because of busybox weirdness ...
	IS_PRE_UPGRADE=
fi

if [ -n "$(rootfs_type)" ]; then
	echo "Switching to ramdisk..."
	switch_to_ramfs
fi

# Exec new shell from ramfs
exec /bin/busybox ash -c "$COMMAND"