#!/bin/sh

RAM_ROOT=/tmp/root

[ -x /usr/bin/ldd ] || ldd() { LD_TRACE_LOADED_OBJECTS=1 $*; }
libs() { ldd $* 2>/dev/null | sed -r 's/(.* => )?(.*) .*/\2/'; }

install_file() { # <file> [ <file> ... ]
	for file in "$@"; do
		dest="$RAM_ROOT/$file"
		[ -f $file -a ! -f $dest ] && {
			dir="$(dirname $dest)"
			mkdir -p "$dir"
			cp $file $dest
		}
	done
}

install_bin() { # <file> [ <symlink> ... ]
	src=$1
	files=$1
	[ -x "$src" ] && files="$src $(libs $src)"
	install_file $files
	shift
	for link in "$@"; do {
		dest="$RAM_ROOT/$link"
		dir="$(dirname $dest)"
		mkdir -p "$dir"
		[ -f "$dest" ] || ln -s $src $dest
	}; done
}

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
}

run_ramfs() { # <command> [...]
	install_bin /bin/busybox /bin/ash /bin/sh /bin/mount /bin/umount	\
		/sbin/pivot_root /sbin/reboot /bin/sync /bin/dd	/bin/grep       \
		/bin/cp /bin/mv /bin/tar /usr/bin/md5sum "/usr/bin/[" /bin/dd	\
		/bin/vi /bin/ls /bin/cat /usr/bin/awk /usr/bin/hexdump		\
		/bin/sleep /bin/zcat /usr/bin/bzcat /usr/bin/printf /usr/bin/wc \
		/bin/cut /usr/bin/printf /bin/sync /bin/mkdir /bin/rmdir	\
		/bin/rm /usr/bin/basename /bin/kill /bin/chmod /usr/bin/find \
		/bin/mknod

	install_bin /sbin/mtd
	install_bin /sbin/mount_root
	install_bin /sbin/snapshot
	install_bin /sbin/snapshot_tool
	install_bin /usr/sbin/ubiupdatevol
	install_bin /usr/sbin/ubiattach
	install_bin /usr/sbin/ubiblock
	install_bin /usr/sbin/ubiformat
	install_bin /usr/sbin/ubidetach
	install_bin /usr/sbin/ubirsvol
	install_bin /usr/sbin/ubirmvol
	install_bin /usr/sbin/ubimkvol
	install_bin /usr/sbin/partx
	install_bin /usr/sbin/losetup
	install_bin /usr/sbin/mkfs.ext4
	for file in $RAMFS_COPY_BIN; do
		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
	}

	# spawn a new shell from ramdisk to reduce the probability of cache issues
	exec /bin/busybox ash -c "$*"
}

kill_remaining() { # [ <signal> [ <loop> ] ]
	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
	done
	echo ""
}

run_hooks() {
	local arg="$1"; shift
	for func in "$@"; do
		eval "$func $arg"
	done
}

ask_bool() {
	local default="$1"; shift;
	local answer="$default"

	[ "$INTERACTIVE" -eq 1 ] && {
		case "$default" in
			0) echo -n "$* (y/N): ";;
			*) echo -n "$* (Y/n): ";;
		esac
		read answer
		case "$answer" in
			y*) answer=1;;
			n*) answer=0;;
			*) answer="$default";;
		esac
	}
	[ "$answer" -gt 0 ]
}

v() {
	[ "$VERBOSE" -ge 1 ] && echo "$@"
}

json_string() {
	local v="$1"
	v="${v//\\/\\\\}"
	v="${v//\"/\\\"}"
	echo "\"$v\""
}

rootfs_type() {
	/bin/mount | awk '($3 ~ /^\/$/) && ($5 !~ /rootfs/) { print $5 }'
}

get_image() { # <source> [ <command> ]
	local from="$1"
	local cat="$2"

	if [ -z "$cat" ]; then
		local magic="$(dd if="$from" bs=2 count=1 2>/dev/null | hexdump -n 2 -e '1/1 "%02x"')"
		case "$magic" in
			1f8b) cat="zcat";;
			425a) cat="bzcat";;
			*) cat="cat";;
		esac
	fi

	$cat "$from" 2>/dev/null
}

get_magic_word() {
	(get_image "$@" | dd bs=2 count=1 | hexdump -v -n 2 -e '1/1 "%02x"') 2>/dev/null
}

get_magic_long() {
	(get_image "$@" | dd bs=4 count=1 | hexdump -v -n 4 -e '1/1 "%02x"') 2>/dev/null
}

export_bootdevice() {
	local cmdline uuid disk uevent
	local MAJOR MINOR DEVNAME DEVTYPE

	if read cmdline < /proc/cmdline; then
		case "$cmdline" in
			*block2mtd=*)
				disk="${cmdline##*block2mtd=}"
				disk="${disk%%,*}"
			;;
			*root=*)
				disk="${cmdline##*root=}"
				disk="${disk%% *}"
			;;
		esac

		case "$disk" in
			PARTUUID=[a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9]-02)
				uuid="${disk#PARTUUID=}"
				uuid="${uuid%-02}"
				for disk in $(find /dev -type b); do
					set -- $(dd if=$disk bs=1 skip=440 count=4 2>/dev/null | hexdump -v -e '4/1 "%02x "')
					if [ "$4$3$2$1" = "$uuid" ]; then
						uevent="/sys/class/block/${disk##*/}/uevent"
						break
					fi
				done
			;;
			/dev/*)
				uevent="/sys/class/block/${disk##*/}/uevent"
			;;
		esac

		if [ -e "$uevent" ]; then
			. "$uevent"

			export BOOTDEV_MAJOR=$MAJOR
			export BOOTDEV_MINOR=$MINOR
			return 0
		fi
	fi

	return 1
}

export_partdevice() {
	local var="$1" offset="$2"
	local uevent MAJOR MINOR DEVNAME DEVTYPE

	for uevent in /sys/class/block/*/uevent; do
		. "$uevent"
		if [ $BOOTDEV_MAJOR = $MAJOR -a $(($BOOTDEV_MINOR + $offset)) = $MINOR -a -b "/dev/$DEVNAME" ]; then
			export "$var=$DEVNAME"
			return 0
		fi
	done

	return 1
}

get_partitions() { # <device> <filename>
	local disk="$1"
	local filename="$2"

	if [ -b "$disk" -o -f "$disk" ]; then
		v "Reading partition table from $filename..."

		local magic="$(hexdump -v -n 2 -s 0x1FE -e '1/2 "0x%04X"' "$disk")"
		if [ "$magic" != 0xAA55 ]; then
			v "Invalid partition table on $disk"
			exit
		fi

		rm -f "/tmp/partmap.$filename"

		local part
		for part in 1 2 3 4; do
			set -- $(hexdump -v -n 12 -s "$((0x1B2 + $part * 16))" -e '3/4 "0x%08X "' "$disk")

			local type="$(($1 % 256))"
			local lba="$(($2))"
			local num="$(($3))"

			[ $type -gt 0 ] || continue

			printf "%2d %5d %7d\n" $part $lba $num >> "/tmp/partmap.$filename"
		done
	fi
}

jffs2_copy_config() {
	if grep rootfs_data /proc/mtd >/dev/null; then
		# squashfs+jffs2
		mtd -e rootfs_data jffs2write "$CONF_TAR" rootfs_data
	else
		# jffs2
		mtd jffs2write "$CONF_TAR" rootfs
	fi
}

# Flash firmware to MTD partition
#
# $(1): path to image
# $(2): (optional) pipe command to extract firmware, e.g. dd bs=n skip=m
default_do_upgrade() {
	sync
	if [ "$SAVE_CONFIG" -eq 1 ]; then
		get_image "$1" "$2" | mtd $MTD_CONFIG_ARGS -j "$CONF_TAR" write - "${PART_NAME:-image}"
	else
		get_image "$1" "$2" | mtd write - "${PART_NAME:-image}"
	fi
}

do_upgrade_stage2() {
	v "Performing system upgrade..."
	if [ -n "$do_upgrade" ]; then
		$do_upgrade "$IMAGE"
	elif type 'platform_do_upgrade' >/dev/null 2>/dev/null; then
		platform_do_upgrade "$IMAGE"
	else
		default_do_upgrade "$IMAGE"
	fi

	if [ "$SAVE_CONFIG" -eq 1 ] && type 'platform_copy_config' >/dev/null 2>/dev/null; then
		platform_copy_config
	fi

	v "Upgrade completed"
	sleep 1

	v "Rebooting system..."
	umount -a
	reboot -f
	sleep 5
	echo b 2>/dev/null >/proc/sysrq-trigger
}