#!/system/bin/sh
### Rozhuk Ivan 2018-2023
### optstart.sh
### 


# Workaround to find 'dirname' on system, at least at /system/xbin - busybox.
export PATH=/bin:/sbin:/system/bin:/system/xbin
export THIS_SCRIPT_NAME=`readlink -nf "${0}"`
export OPT_BIN_DIR=`dirname "${THIS_SCRIPT_NAME}"`
export OPT_ROOT_DIR=`dirname "${OPT_BIN_DIR}"`
export OPT_ROOT_PARENT_DIR=`dirname "${OPT_ROOT_DIR}"`
# Restore PATH.
export PATH=${OPT_ROOT_DIR}/bin:${OPT_ROOT_DIR}/sbin:/bin:/sbin:/system/bin:/system/xbin
MNT_POINT_LIST='/ /system /system_ext /system/system_ext'


echo "optstart.sh: ${0}: init entware: ${OPT_ROOT_DIR}" > /dev/kmsg


# Sleep for few random seconds to reduce possible concurence.
# Use last digit of shell PID as random.
sleep `echo ${$} | tr -d '\n' | tail -c1`


# Check is we need run.
if [ -f "${OPT_ROOT_DIR}/var/run/entware_init_done" ]; then
	echo "optstart.sh: ${0}: entware already initialized." > /dev/kmsg
	return 0
fi


# Check user/selinux context.
if [ -f '/system/bin/id' ]; then
	__SELINUX_CONTEXT=`/system/bin/id -Z`
	case "${__SELINUX_CONTEXT}" in
	(*'u:r:su:s0'*|*'magisk'*) # 'u:r:su:s0', 'context=u:r:magisk:s0'
		echo "optstart.sh: ${0}: running as ${__SELINUX_CONTEXT}." > /dev/kmsg
		;;
	*)
		# Try to change SeLinux context to magisk.
		echo "optstart.sh: ${0}: need to re run ${THIS_SCRIPT_NAME} as root@magisk." > /dev/kmsg
		if [ -f '/sbin/su' ]; then
			/sbin/su sh -c "${THIS_SCRIPT_NAME}" > /dev/kmsg 2>&1
			return 0
		fi
		if [ -f '/system/bin/su' ]; then
			/system/bin/su sh -c "${THIS_SCRIPT_NAME}" > /dev/kmsg 2>&1
			return 0
		fi
		echo "optstart.sh: ${0}: su not found, expect fail to start." > /dev/kmsg
		;;
	esac
fi


# Prepare rootfs.
if [ ! -e '/opt' ] || [ ! -e '/etc' ] || [ ! -e '/bin' ]; then
	# Unprotect.
	/system/bin/mount -o rw,remount '/' > /dev/kmsg 2>&1
	# Make /opt.
	if [ ! -e '/opt' ]; then
		# Prefer dir+mount by historic reasons with samsung devices.
		mkdir -p '/opt' > /dev/kmsg 2>&1
		if [ -d '/opt' ]; then
			chmod 0755 '/opt' > /dev/kmsg 2>&1
		else
			# Probably not enough space.
			ln -sf "${OPT_ROOT_DIR}" '/' > /dev/kmsg 2>&1
		fi
		/system/bin/chcon 'u:object_r:system_file:s0' '/opt' > /dev/kmsg 2>&1
	fi
	# Make /etc.
	if [ ! -e '/etc' ]; then
		ln -sf '/system/etc' '/' > /dev/kmsg 2>&1
	fi
	# Make /bin and sh.
	if [ ! -e '/bin' ]; then
		ln -sf "/system/bin" '/' > /dev/kmsg 2>&1
	fi
	# Protect again.
	/system/bin/mount -o ro,remount '/' > /dev/kmsg 2>&1
fi


# Mount staff.
_bind_file_opt2sys() { # filename
	local __SRC="${OPT_ROOT_DIR}/etc/${1}"
	local __DST="/system/etc/${1}"
	# Is source file exist?
	[ ! -f "${__SRC}" ] && return 0
	# Is target file exist and it is not symlink?
	if [ ! -f "${__DST}" ] || [ -L "${__DST}" ]; then
		# Remount as RW.
		for __MNT_POINT in ${MNT_POINT_LIST}; do
			[ ! -r "${__MNT_POINT}" ] && continue
			/system/bin/mount -o rw,remount "${__MNT_POINT}" > /dev/null 2>&1
		done
		# Create empty file.
		rm -f "${__DST}" > /dev/kmsg 2>&1
		touch "${__DST}" > /dev/kmsg 2>&1
		chmod 0644 "${__DST}" > /dev/kmsg 2>&1
		chown 0:0 "${__DST}" > /dev/kmsg 2>&1
		/system/bin/chcon 'u:object_r:system_file:s0' "${__DST}" > /dev/kmsg 2>&1
		# Remount as RO.
		for __MNT_POINT in ${MNT_POINT_LIST}; do
			[ ! -r "${__MNT_POINT}" ] && continue
			/system/bin/mount -o ro,remount "${__MNT_POINT}" > /dev/null 2>&1
		done
	fi
	# Mount bind.
	/system/bin/mount -o ro,bind "${__SRC}" "${__DST}" > /dev/kmsg 2>&1
}
_link_file_opt2sys() { # filename
	local __SRC="${OPT_ROOT_DIR}/etc/${1}"
	local __DST="/system/etc/${1}"
	# Is source file exist?
	[ ! -f "${__SRC}" ] && return 0
	# Is target file exist and point to proper location?
	[ "${__SRC}" == `readlink -nf "${__DST}"` ] && return 0
	# Remount as RW.
	for __MNT_POINT in ${MNT_POINT_LIST}; do
		[ ! -r "${__MNT_POINT}" ] && continue
		/system/bin/mount -o rw,remount "${__MNT_POINT}" > /dev/null 2>&1
	done
	# Create symlink.
	rm -f "${__DST}" > /dev/kmsg 2>&1
	ln -sfv "${__SRC}" '/system/etc/' > /dev/kmsg 2>&1
	chmod 0644 "${__DST}" > /dev/kmsg 2>&1
	chown 0:0 "${__DST}" > /dev/kmsg 2>&1
	/system/bin/chcon 'u:object_r:system_file:s0' "${__DST}" > /dev/kmsg 2>&1
	# Remount as RO.
	for __MNT_POINT in ${MNT_POINT_LIST}; do
		[ ! -r "${__MNT_POINT}" ] && continue
		/system/bin/mount -o ro,remount "${__MNT_POINT}" > /dev/null 2>&1
	done
}
# Mount /opt root, if not symlinked.
if [ -d '/opt' ] && [ ! -L '/opt' ]; then
	/system/bin/mount -o rw,bind "${OPT_ROOT_DIR}" '/opt' > /dev/kmsg 2>&1
fi
# Mount tmpfs.
/system/bin/mount -t tmpfs -o rw,nosuid,nodev,size=32m tmpfs "${OPT_ROOT_DIR}/tmp" > /dev/kmsg 2>&1
/system/bin/mount -t tmpfs -o rw,nosuid,nodev,size=8m tmpfs "${OPT_ROOT_DIR}/var/log" > /dev/kmsg 2>&1
/system/bin/mount -t tmpfs -o rw,nosuid,nodev,size=2m tmpfs "${OPT_ROOT_DIR}/var/run" > /dev/kmsg 2>&1
# Bind files.
# Hosts file not work on Android 12+ if it symlink.
_bind_file_opt2sys 'hosts'
# Link files.
# entware build busybox with glibc, it requires /etc/resolv.conf and
# /etc/nsswitch.conf to resolve domain names.
for __FILE2SYS in 'group' 'passwd' 'nsswitch.conf' 'resolv.conf'; do
	_link_file_opt2sys "${__FILE2SYS}"
done


# Mark here as started, service init may take long time.
touch "${OPT_ROOT_DIR}/var/run/entware_init_done"


# Start services.
# Make sure tha SSH bootstrap done.
if [ ! -s "${OPT_ROOT_DIR}/etc/ssh/ssh_host_rsa_key" ] || \
   [ ! -s "${OPT_ROOT_DIR}/etc/ssh/ssh_host_ecdsa_key" ] || \
   [ ! -s "${OPT_ROOT_DIR}/etc/ssh/ssh_host_ed25519_key" ]; then
	# Remount as RW.
	for __MNT_POINT in ${OPT_ROOT_PARENT_DIR} ${OPT_ROOT_DIR} '/opt'; do
		[ ! -r "${__MNT_POINT}" ] && continue
		/system/bin/mount -o rw,remount "${__MNT_POINT}" > /dev/null 2>&1
	done
	# Generating SSH host keys.
	${OPT_ROOT_DIR}/bin/ssh-keygen -A
	# Remount as RO.
	for __MNT_POINT in ${OPT_ROOT_PARENT_DIR} ${OPT_ROOT_DIR} '/opt'; do
		[ ! -r "${__MNT_POINT}" ] && continue
		/system/bin/mount -o ro,remount "${__MNT_POINT}" > /dev/null 2>&1
	done
fi
unset LD_LIBRARY_PATH
unset LD_PRELOAD
${OPT_ROOT_DIR}/etc/init.d/rc.unslung start > /dev/kmsg 2>&1


echo "optstart.sh: ${0}: entware init done." > /dev/kmsg


# Workaround: after this process exit init system may kill all child
# zombie processes to cleanup resources.
# Loop forever.
while true; do
        sleep 60000;
done