genkernel_fork/generic/linuxrc

#!/bin/sh
# Daniel Robbins <drobbins@gentoo.org>
# Copyright 2003 Gentoo Technologies, Inc.
# Distributed under the GPL

. /etc/initrd.defaults
. /etc/initrd.scripts

USE_DEVFS_NORMAL=1

mount -o remount,rw /
mount /proc

[ -n "$QUIET" ] && echo "0" > /proc/sys/kernel/printk

echo "${GOOD} Gentoo initrd startup..."
echo "STEP 1: Command-line parsing"
CMDLINE=`cat /proc/cmdline`
# Scan CMDLINE for any specified real_root= or cdroot arguments
for x in ${CMDLINE}
do
	case "${x}" in
		real_root\=*)
			REAL_ROOT=`parse_opt "${x}"`
		;;
		cdroot)
			CDROOT=1
			REAL_ROOT=""
		;;
		devfs)
			USE_DEVFS_NORMAL=1
		;;
		nodevfs)
			USE_DEVFS_NORMAL=0
		;;
		loop\=*)
			LOOP=`parse_opt "${x}"`
		;;
		looptype\=*)
			LOOPTYPE=`parse_opt "${x}"`
		;;
		*)
		;;
	esac
done

# Scan CMDLINE for any "doscsi" or "noscsi"-type arguments
for x in $HWOPTS
do
	for y in $CMDLINE
	do
		if [ "$y" = "do${x}" ] 
		then
			MY_HWOPTS="${MY_HWOPTS} $x"
		elif [ "$y" = "no${x}" ] 
		then
			MY_HWOPTS="`echo ${MY_HWOPTS} | sed -e 's/${x}//g' -`"
		fi
	done
done

if [ -d "/lib/modules" ]
then
	echo "STEP 2: Module loading"
	# Load appropriate kernel modules
	for x in $MY_HWOPTS
	do
		modules_scan $x
	done
else
	echo "STEP 2: Skipping module load. No modules in initrd"
fi

echo "STEP 3: Mounting necessary filesystems per boot options"

mkdir /newroot
if [ "${CDROOT}" -eq "1" ]
then
	mount -t tmpfs tmpfs /newroot
	mkdir /newroot/dev /newroot/mnt /newroot/mnt/cdrom /newroot/mnt/livecd /newroot/tmp /newroot/tmp/.initrd /newroot/mnt/gentoo
	[ ! -e /newroot/dev/.devfsd ] && mount -t devfs devfs /newroot/dev
	devfsd /newroot/dev -np
	sleep 1

	findcdmount /newroot/dev/cdroms/*
	# not in /dev/cdroms try /dev/ide/cd
	if [ "${REAL_ROOT}" = "" ]
	then
		findcdmount /newroot/dev/ide/cd/*
	fi


	if [ "${REAL_ROOT}" = "" ]
	then
		echo "Dropping to shell so you can fix your shit"
		exec /bin/ash

		# Undo stuff		
		# kill_devfsd # We run devfsd with -np now
		sleep 1
		umount /newroot/dev/
		sleep 1
		umount /newroot
		# shouldn't be anything in here b/c it was on tmpfs
		rm -rf /newroot/*
		CDROOT=0
		echo "Could not find CD to boot, gonna need something else"
	fi
fi

# Don't do else b/c we set CDROOT=0 if it fails to detect
if [ "${CDROOT}" -eq "0" -a "${USE_DEVFS_NORMAL}" -eq "1" ]
then
	[ ! -e /dev/.devfsd ] && mount -t devfs devfs /dev
	devfsd /dev -np
fi

echo "STEP 4: Determining root device"

while true
do
	while [ "${got_good_root}" != "1" ]
	do
		
		if [ "${REAL_ROOT}" = "shell" ]
		then
			/bin/ash

			#set REAL_ROOT to "" so we get a prompt for the real root after the shell exits.
			REAL_ROOT=""
			got_good_root=0
			continue
		elif [ "${REAL_ROOT}" = "" ]
		then
			#no REAL_ROOT determined/specified. Prompt user for root block device.
			echo "Root block device unspecified or not detected."
			echo "Please specify a device to boot, or \"shell\" for a shell."
			echo -n ": "
			read REAL_ROOT
			got_good_root=0
		elif [ -b "${REAL_ROOT}" ]
		then
			got_good_root=1
		else
			REAL_ROOT=""
			got_good_root=0
		fi
	done


	if [ "${CDROOT}" -eq "1" -a "${got_good_root}" = "1" ]
	then
		break
	else
		echo "STEP 4a: Mounting root"

		mount -o rw ${REAL_ROOT} /newroot
		if [ "$?" = "0" ]
		then
			break
		else
			echo "Could not mount specified ROOT, try again"
			got_good_root=0
			REAL_ROOT=""
		fi
	fi
done

[ -n "$QUIET" ] && echo "6" > /proc/sys/kernel/printk
echo "STEP 5: Finishing up"

check_loop() {
	if [ "${LOOP}" = "" -o ! -e "mnt/cdrom/${LOOP}" ]
	then
		echo "Invalid loop location: ${LOOP}"
		echo "please export LOOP with a valid location, or reboot and pass a proper loop="
		echo "kernel command line"
		/bin/ash
	fi
}

if [ "${CDROOT}" = "1" ]
then
	echo "STEP 5a: filling tmpfs filesystem"
	cd /newroot

	# Failsafe if some idiot didn't set loop type
	if [ "${LOOPTYPE}" = "" ]
	then
		echo "YOU FORGOT TO SPECIFY LOOPTYPE TRYING TO AUTODETECT"
		if [ "${LOOP}" = "/livecd.loop" ]
		then
			LOOPTYPE="normal"
		elif [ "${LOOP}" = "/zisofs" ]
		then
			LOOPTYPE="zisofs"
		elif [ "${LOOP}" = "/livecd.squashfs" ]
		then
			LOOPTYPE="squashfs"
		elif [ "${LOOP}" = "/livecd.gcloop" ]
		then
			LOOPTYPE="gcloop"
		else
			LOOPTYPE="noloop"
		fi
		echo "DETECTED LOOPTYPE: $LOOPTYPE"
	fi

	if [ "${LOOPTYPE}" = "normal" ]
	then
		check_loop
		
		# bind-mount /dev/ so that loop devices can be found
		mount -o bind /newroot/dev /dev

		echo "STEP 5a1: mounting loop filesystem"
		mount -t ext2 -o loop,ro /newroot/mnt/cdrom/${LOOP} /newroot/mnt/livecd
		if [ "$?" != "0" ]
		then
			echo "FAILED TO MOUNT LOOP FILESYSTEM, barfing out to shell"
			/bin/ash
		fi
		FS_LOCATION="mnt/livecd"
		umount /dev
	elif [ "${LOOPTYPE}" = "squashfs" ]
	then
		check_loop
		mount -o bind /newroot/dev /dev
		echo "STEP 5a1: mounting squashfs filesystem"
		mount -t squashfs -o loop,ro /newroot/mnt/cdrom/${LOOP} /newroot/mnt/livecd
		if [ "$?" != "0" ]
		then
			echo "FAILED TO MOUNT LOOP FILESYSTEM, barfing out to shell"
			/bin/ash
		fi
		FS_LOCATION="mnt/livecd"
		umount /dev
	elif [ "${LOOPTYPE}" = "gcloop" ]
	then
		check_loop
		mount -o bind /newroot/dev /dev
		echo "STEP 5a1: mounting gcloop (ext2) filesystem"
		echo " " | losetup -E 19 -e ucl-0 -p0 /newroot/dev/loop0 /newroot/mnt/cdrom/${LOOP}
		if [ "$?" != "0" ]
		then
			echo "FAILED TO losetup THE LOOP DEVICE"
			/bin/ash
		fi
		mount -t ext2 -o ro /newroot/dev/loop0 /newroot/mnt/livecd
		FS_LOCATION="mnt/livecd"
		umount /dev
	elif [ "${LOOPTYPE}" = "zisofs" ]
	then
		check_loop
		FS_LOCATION="mnt/cdrom/${LOOP}"
	elif [ "${LOOPTYPE}" = "noloop" ]
	then
		FS_LOCATION="mnt/cdrom"
	fi

	echo "STEP 5a2: filling filesystem"
	for x in ${ROOT_LINKS}
	do
		ln -s "${FS_LOCATION}/${x}" "${x}"
	done
	mkdir initrd proc tmp sys
	chmod 1777 tmp
	(cd /newroot/${FS_LOCATION}; cp -a ${ROOT_TREES} /newroot)
else
	echo "STEP 5b: setting up stuff for pivot_root"
	mkdir -p /newroot/tmp/.initrd
fi

echo "STEP 5c: redirect console"
console=/newroot/dev/console
[ ! -e "$console" ] && mknod $console c 5 1
exec < $console > $console 2>&1 || echo "CONSOLE REDIRECTION FAILED, /dev ON ROOT DOES NOT CONTAIN console !!!"

echo "STEP 6: pivot_root and exec/chroot real init"


cd /newroot
pivot_root . tmp/.initrd

if [ "${USE_DEVFS_NORMAL}" -eq "1" -a "${CDROOT}" -eq "0" ]
then
	# must mount a new devfs before we can
	# umount the old one for some reason
	mount -t proc proc /proc
	mount -t devfs devfs /dev
	umount /tmp/.initrd/proc || echo "COULD NOT UMOUNT tmp/.initrd/proc !!!"
	umount /tmp/.initrd/dev || echo "COULD NOT UMOUNT tmp/.initrd/dev !!!"

	# at this point it lets us umount the new
	# devfs, don't know why, just does, stop
	# asking questions!
	umount /dev
	umount /proc
	cp -f /etc/mtab /etc/mtab.initrd-here > /dev/null 2>&1

elif [ "${CDROOT}" -eq "1" ]
then
	# If automount at boot was on with devfs, we'll want to umount it
	# also umount proc
	echo "STEP 6a: clean up mounts"
	mount -t proc proc /proc
	umount /tmp/.initrd/proc > /dev/null 2>&1 || echo "COULD NOT UMOUNT /tmp/.initrd/proc !!!"
	umount /dev > /dev/null 2>&1
	umount /proc > /dev/null 2>&1
fi

# /usr/src/linux/Documentation/initrd.txt 
# here's the line it says we should do:
#       exec chroot . /sbin/init </dev/console >/dev/console 2>&1

exec chroot . /bin/sh <<- EOF
	umount /tmp/.initrd || echo "UMOUNT of /tmp/.initrd FAILED!!!" && /sbin/blockdev --flushbufs /dev/ram0
	echo "INIT: starting /sbin/init ${CMDLINE}"
	exec /sbin/init ${CMDLINE}
EOF

# exec chroot . /sbin/init ${CMDLINE} < /dev/console > /dev/console 2>&1
echo "IF YOU ARE SEEING THIS MESSAGE, A FATAL ERROR HAS OCCURRED"
echo "MOST LIKELY /sbin/init DOES NOT EXIST, ATTEMPTING TO DROP"
echo "YOU TO A SHELL"

exec /bin/bash
exec /bin/sh
exec /bin/ash
exec sh