initramfs-tools/init

#!/bin/sh

echo "Loading, please wait..."

[ -d /dev ] || mkdir -m 0755 /dev
[ -d /root ] || mkdir -m 0700 /root
[ -d /sys ] || mkdir /sys
[ -d /proc ] || mkdir /proc
[ -d /tmp ] || mkdir /tmp
mkdir -p /var/lock
mount -t sysfs -o nodev,noexec,nosuid sysfs /sys
mount -t proc -o nodev,noexec,nosuid proc /proc

# Note that this only becomes /dev on the real filesystem if udev's scripts
# are used; which they will be, but it's worth pointing out
tmpfs_size="10M"
if [ -e /etc/udev/udev.conf ]; then
	. /etc/udev/udev.conf
fi
if ! mount -t devtmpfs -o size=$tmpfs_size,mode=0755 udev /dev; then
	echo "W: devtmpfs not available, falling back to tmpfs for /dev"
	mount -t tmpfs -o size=$tmpfs_size,mode=0755 udev /dev
	[ -e /dev/console ] || mknod -m 0600 /dev/console c 5 1
	[ -e /dev/null ] || mknod /dev/null c 1 3
fi
mkdir /dev/pts
mount -t devpts -o noexec,nosuid,gid=5,mode=0620 devpts /dev/pts || true
mount -t tmpfs -o "nosuid,size=20%,mode=0755" tmpfs /run
mkdir -m 0755 /run/initramfs

# Export the dpkg architecture
export DPKG_ARCH=
. /conf/arch.conf

# Set modprobe env
export MODPROBE_OPTIONS="-qb"

# Export relevant variables
export ROOT=
export ROOTDELAY=
export ROOTFLAGS=
export ROOTFSTYPE=
export IP=
export BOOT=
export BOOTIF=
export UBIMTD=
export break=
export init=/sbin/init
export quiet=n
export readonly=y
export rootmnt=/root
export debug=
export panic=
export blacklist=
export resume=
export resume_offset=

# Bring in the main config
. /conf/initramfs.conf
for conf in conf/conf.d/*; do
	[ -f ${conf} ] && . ${conf}
done
. /scripts/functions

# Parse command line options
for x in $(cat /proc/cmdline); do
	case $x in
	init=*)
		init=${x#init=}
		;;
	root=*)
		ROOT=${x#root=}
		case $ROOT in
		LABEL=*)
			ROOT="${ROOT#LABEL=}"

			# support any / in LABEL= path (escape to \x2f)
			case "${ROOT}" in
			*/*)
			if command -v sed >/dev/null 2>&1; then
				ROOT="$(echo ${ROOT} | sed 's,/,\\x2f,g')"
			else
				if [ "${ROOT}" != "${ROOT#/}" ]; then
					ROOT="\x2f${ROOT#/}"
				fi
				if [ "${ROOT}" != "${ROOT%/}" ]; then
					ROOT="${ROOT%/}\x2f"
				fi
				IFS='/'
				newroot=
				for s in $ROOT; do
					newroot="${newroot:+${newroot}\\x2f}${s}"
				done
				unset IFS
				ROOT="${newroot}"
			fi
			esac
			ROOT="/dev/disk/by-label/${ROOT}"
			;;
		UUID=*)
			ROOT="/dev/disk/by-uuid/${ROOT#UUID=}"
			;;
		/dev/nfs)
			[ -z "${BOOT}" ] && BOOT=nfs
			;;
		esac
		;;
	rootflags=*)
		ROOTFLAGS="-o ${x#rootflags=}"
		;;
	rootfstype=*)
		ROOTFSTYPE="${x#rootfstype=}"
		;;
	rootdelay=*)
		ROOTDELAY="${x#rootdelay=}"
		case ${ROOTDELAY} in
		*[![:digit:].]*)
			ROOTDELAY=
			;;
		esac
		;;
	nfsroot=*)
		NFSROOT="${x#nfsroot=}"
		;;
	ip=*)
		IP="${x#ip=}"
		;;
	boot=*)
		BOOT=${x#boot=}
		;;
	ubi.mtd=*)
		UBIMTD=${x#ubi.mtd=}
		;;
	resume=*)
		RESUME="${x#resume=}"
		;;
	resume_offset=*)
		resume_offset="${x#resume_offset=}"
		;;
	noresume)
		noresume=y
		;;
	panic=*)
		panic="${x#panic=}"
		case ${panic} in
		*[![:digit:].]*)
			panic=
			;;
		esac
		;;
	quiet)
		quiet=y
		;;
	ro)
		readonly=y
		;;
	rw)
		readonly=n
		;;
	debug)
		debug=y
		quiet=n
		exec >/run/initramfs/initramfs.debug 2>&1
		set -x
		;;
	debug=*)
		debug=y
		quiet=n
		set -x
		;;
	break=*)
		break=${x#break=}
		;;
	break)
		break=premount
		;;
	blacklist=*)
		blacklist=${x#blacklist=}
		;;
	netconsole=*)
		netconsole=${x#netconsole=}
		;;
	BOOTIF=*)
		BOOTIF=${x#BOOTIF=}
		;;
	esac
done

# Default to BOOT=local if no boot script defined.
if [ -z "${BOOT}" ]; then
	BOOT=local
fi

if [ -n "${noresume}" ]; then
	export noresume
	unset resume
else
	resume=${RESUME:-}
fi

maybe_break top

# Don't do log messages here to avoid confusing graphical boots
run_scripts /scripts/init-top

maybe_break modules
[ "$quiet" != "y" ] && log_begin_msg "Loading essential drivers"
load_modules
[ "$quiet" != "y" ] && log_end_msg

[ -n "${netconsole}" ] && modprobe netconsole netconsole="${netconsole}"

maybe_break premount
[ "$quiet" != "y" ] && log_begin_msg "Running /scripts/init-premount"
run_scripts /scripts/init-premount
[ "$quiet" != "y" ] && log_end_msg

maybe_break mount
log_begin_msg "Mounting root file system"
. /scripts/${BOOT}
parse_numeric ${ROOT}
maybe_break mountroot
mountroot
log_end_msg

maybe_break bottom
[ "$quiet" != "y" ] && log_begin_msg "Running /scripts/init-bottom"
run_scripts /scripts/init-bottom
[ "$quiet" != "y" ] && log_end_msg

# Preserve information on old systems without /run on the rootfs
if [ -d ${rootmnt}/run ]; then
	mount -n -o move /run ${rootmnt}/run
else
	# The initramfs udev database must be migrated:
	if [ -d /run/udev ] && [ ! -d /dev/.udev ]; then
		mv /run/udev /dev/.udev
	fi
	# The initramfs debug info must be migrated:
	if [ -d /run/initramfs ] && [ ! -d /dev/.initramfs ]; then
		mv /run/initramfs /dev/.initramfs
	fi
	umount /run
fi

validate_init() {
	checktarget="${1}"

	# Work around absolute symlinks
	if [ -d "${rootmnt}" ] && [ -h "${rootmnt}${checktarget}" ]; then
		case $(readlink "${rootmnt}${checktarget}") in /*)
			checktarget="$(chroot ${rootmnt} readlink ${checktarget})"
			;;
		esac
	fi

	# Make sure the specified init can be executed
	if [ ! -x "${rootmnt}${checktarget}" ]; then
		return 1
	fi

	# Upstart uses /etc/init as configuration directory :-/
	if [ -d "${rootmnt}${checktarget}" ]; then
		return 1
	fi
}

# Check init bootarg
if [ -n "${init}" ]; then
	if ! validate_init "$init"; then
		echo "Target filesystem doesn't have requested ${init}."
		init=
	fi
fi

# Common case: /sbin/init is present
if [ ! -x "${rootmnt}/sbin/init" ]; then
	# ... if it's not available search for valid init
	if [ -z "${init}" ] ; then
		for inittest in /sbin/init /etc/init /bin/init /bin/sh; do
			if validate_init "${inittest}"; then
				init="$inittest"
				break
			fi
		done
	fi

	# No init on rootmount
	if ! validate_init "${init}" ; then
		panic "No init found. Try passing init= bootarg."
	fi
fi

maybe_break init

# don't leak too much of env - some init(8) don't clear it
# (keep init, rootmnt)
unset debug
unset MODPROBE_OPTIONS
unset DPKG_ARCH
unset ROOTFLAGS
unset ROOTFSTYPE
unset ROOTDELAY
unset ROOT
unset IP
unset BOOT
unset BOOTIF
unset UBIMTD
unset blacklist
unset break
unset noresume
unset panic
unset quiet
unset readonly
unset resume
unset resume_offset

# Move virtual filesystems over to the real filesystem
mount -n -o move /sys ${rootmnt}/sys
mount -n -o move /proc ${rootmnt}/proc

# Chain to real filesystem
if command -v switch_root >/dev/null 2>&1; then
	exec switch_root ${rootmnt} ${init} "$@" <${rootmnt}/dev/console >${rootmnt}/dev/console
elif command -v run-init >/dev/null 2>&1; then
	exec run-init ${rootmnt} ${init} "$@" <${rootmnt}/dev/console >${rootmnt}/dev/console
fi
echo "Something went badly wrong in the initramfs."
panic "Please file a bug on initramfs-tools."