最終更新:2015-07-18 (土) 03:41:06 (1784d)  

initramfs/init
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メモ

mkinitramfsのソース

  • Linux/usr/share/initramfs-tools/init?

Ubuntu

  • #!/bin/sh
    
    [ -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
    # Some things don't work properly without /etc/mtab.
    ln -sf /proc/mounts /etc/mtab
    
    grep -q '\<quiet\>' /proc/cmdline || echo "Loading, please wait..."
    
    # 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
    if ! mount -t devtmpfs -o mode=0755 udev /dev; then
    	echo "W: devtmpfs not available, falling back to tmpfs for /dev"
    	mount -t tmpfs -o 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 /run/initramfs
    # compatibility symlink for the pre-oneiric locations
    ln -s /run/initramfs /dev/.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=
    export recovery=
    
    # mdadm needs hostname to be set. This has to be done before the udev rules are called!
    if [ -f "/etc/hostname" ]; then
            /bin/hostname -b -F /etc/hostname 2>&1 1>/dev/null
    fi
    
    # 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 ${ROOTDELAY} in
    		*[![:digit:].]*)
    			ROOTDELAY=
    			;;
    		esac
    		;;
    	resumedelay=*)
    		RESUMEDELAY="${x#resumedelay=}"
    		;;
    	loop=*)
    		LOOP="${x#loop=}"
    		;;
    	loopflags=*)
    		LOOPFLAGS="-o ${x#loopflags=}"
    		;;
    	loopfstype=*)
    		LOOPFSTYPE="${x#loopfstype=}"
    		;;
    	cryptopts=*)
    		cryptopts="${x#cryptopts=}"
    		;;
    	nfsroot=*)
    		NFSROOT="${x#nfsroot=}"
    		;;
    	netboot=*)
    		NETBOOT="${x#netboot=}"
    		;;
    	ip=*)
    		IP="${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=${x#BOOTIF=}
    		;;
    	hwaddr=*)
    		BOOTIF=${x#BOOTIF=}
    		;;
    	recovery)
    		recovery=y
    		;;
    	esac
    done
    
    if [ -n "${noresume}" ]; then
    	export noresume
    	unset resume
    else
    	resume=${RESUME:-}
    fi
    
    maybe_break top
    
    # export BOOT variable value for compcache,
    # so we know if we run from casper
    export BOOT
    
    # 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
    
    # Move virtual filesystems over to the real filesystem
    mount -n -o move /sys ${rootmnt}/sys
    mount -n -o move /proc ${rootmnt}/proc
    
    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
    
    # Chain to real filesystem
    exec run-init ${rootmnt} ${init} "$@" ${recovery:+--startup-event=recovery} <${rootmnt}/dev/console >${rootmnt}/dev/console 2>&1
    panic "Could not execute run-init."

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