База знаний » GNU/Linux

h1. Initramfs

/init

<pre>

#!/bin/busybox sh

# Mount the /proc and /sys filesystems.

mount -t proc none /proc

mount -t sysfs none /sys

# Do your stuff here.

echo "This script mounts rootfs and boots it up, nothing more!"

rescue_shell() {

    echo "Something went wrong. Dropping you to a shell."

    busybox --install -s

    exec /bin/sh

}

mini_udev() {

    ln -s ../bin/busybox /sbin/mdev

    echo /sbin/mdev > /proc/sys/kernel/hotplug

    /sbin/mdev -s

}

# Use devtmpfs if possible

if grep -qs devtmpfs /proc/filesystems; then

    mount -n -t devtmpfs -o "exec,nosuid,mode=0755,size=10M" udev /dev

    devtmpfs=true

else    

    mini_udev

    devtmpfs=false

fi

uuidlabel_root() {

    for cmd in $(cat /proc/cmdline) ; do

        case $cmd in

        root=*)

	    mkdir -p /etc/lvm

	    echo 'devices { filter = [ "a|/dev/md[0-9]+$|", "a|/dev/[hsv]d[a-z][0-9]*$|", "r/.*/" ] }' > /etc/lvm/lvm.conf

	    echo 'activation { udev_rules = 0 }' >> /etc/lvm/lvm.conf

	    /sbin/lvm vgscan

	    /sbin/lvm vgchange -ay --sysinit

            type=$(echo $cmd | cut -d= -f2)

            if [ $type == "LABEL" ] || [ $type == "UUID" ] ; then

                uuid=$(echo $cmd | cut -d= -f3)

                mount -o ro $(blkid |grep "$type=\"$uuid\"" | cut -d: -f1 | grep -v '/dev/dm-[0-9]*$\|-real$' | sort | head -n1 ) /mnt/root || rescue_shell

            else

                mount -o ro $(echo $cmd | cut -d= -f2) /mnt/root || rescue_shell

            fi

            ;;

	rescue)

	    rescue_shell

	    ;;

        esac

    done

}

uuidlabel_root || rescue_shell

# Remount /dev if devtmpfs

$devtmpfs && mount -n --move /dev /mnt/root/dev

# Clean up.

umount /proc

umount /sys

# Boot the real thing.

exec switch_root /mnt/root /sbin/init

</pre>

<pre>

cd initramfs

find | cpio -o -H newc | gzip -9 > ../initramfs-2012-04-03.igz

</pre>