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|
#!/bin/sh
PATH=/sbin:/bin:/usr/sbin:/usr/bin
ROOT_MOUNT="/rootfs/"
ROOT_IMAGE="rootfs.img"
MOUNT="/bin/mount"
UMOUNT="/bin/umount"
ISOLINUX=""
ROOT_DISK=""
# Copied from initramfs-framework. The core of this script probably should be
# turned into initramfs-framework modules to reduce duplication.
udev_daemon() {
OPTIONS="/sbin/udev/udevd /sbin/udevd /lib/udev/udevd /lib/systemd/systemd-udevd"
for o in $OPTIONS; do
if [ -x "$o" ]; then
echo $o
return 0
fi
done
return 1
}
_UDEV_DAEMON=`udev_daemon`
early_setup() {
mkdir -p /proc
mkdir -p /sys
mount -t proc proc /proc
mount -t sysfs sysfs /sys
mount -t devtmpfs none /dev
# support modular kernel
modprobe isofs 2> /dev/null
mkdir -p /run
mkdir -p /var/run
$_UDEV_DAEMON --daemon
udevadm trigger --action=add
}
read_args() {
[ -z "$CMDLINE" ] && CMDLINE=`cat /proc/cmdline`
for arg in $CMDLINE; do
optarg=`expr "x$arg" : 'x[^=]*=\(.*\)'`
case $arg in
root=*)
ROOT_DEVICE=$optarg ;;
rootimage=*)
ROOT_IMAGE=$optarg ;;
rootfstype=*)
modprobe $optarg 2> /dev/null ;;
LABEL=*)
label=$optarg ;;
video=*)
video_mode=$arg ;;
vga=*)
vga_mode=$arg ;;
console=*)
if [ -z "${console_params}" ]; then
console_params=$arg
else
console_params="$console_params $arg"
fi ;;
debugshell*)
if [ -z "$optarg" ]; then
shelltimeout=30
else
shelltimeout=$optarg
fi
esac
done
}
boot_live_root() {
# Watches the udev event queue, and exits if all current events are handled
udevadm settle --timeout=3 --quiet
killall "${_UDEV_DAEMON##*/}" 2>/dev/null
# Allow for identification of the real root even after boot
mkdir -p ${ROOT_MOUNT}/media/realroot
mount -n --move "/run/media/${ROOT_DISK}" ${ROOT_MOUNT}/media/realroot
# Move the mount points of some filesystems over to
# the corresponding directories under the real root filesystem.
for dir in `awk '/\/dev.* \/run\/media/{print $2}' /proc/mounts`; do
mkdir -p ${ROOT_MOUNT}/media/${dir##*/}
mount -n --move $dir ${ROOT_MOUNT}/media/${dir##*/}
done
mount -n --move /proc ${ROOT_MOUNT}/proc
mount -n --move /sys ${ROOT_MOUNT}/sys
mount -n --move /dev ${ROOT_MOUNT}/dev
cd $ROOT_MOUNT
# busybox switch_root supports -c option
exec switch_root -c /dev/console $ROOT_MOUNT /sbin/init $CMDLINE ||
fatal "Couldn't switch_root, dropping to shell"
}
fatal() {
echo $1 >$CONSOLE
echo >$CONSOLE
exec sh
}
early_setup
[ -z "$CONSOLE" ] && CONSOLE="/dev/console"
read_args
echo "Waiting for removable media..."
C=0
while true
do
for i in `ls /run/media 2>/dev/null`; do
if [ -f /run/media/$i/$ROOT_IMAGE ] ; then
found="yes"
ROOT_DISK="$i"
break
elif [ -f /run/media/$i/isolinux/$ROOT_IMAGE ]; then
found="yes"
ISOLINUX="isolinux"
ROOT_DISK="$i"
break
fi
done
if [ "$found" = "yes" ]; then
break;
fi
# don't wait for more than $shelltimeout seconds, if it's set
if [ -n "$shelltimeout" ]; then
echo -n " " $(( $shelltimeout - $C ))
if [ $C -ge $shelltimeout ]; then
echo "..."
echo "Mounted filesystems"
mount | grep media
echo "Available block devices"
cat /proc/partitions
fatal "Cannot find $ROOT_IMAGE file in /run/media/* , dropping to a shell "
fi
C=$(( C + 1 ))
fi
sleep 1
done
# Try to mount the root image read-write and then boot it up.
# This function distinguishes between a read-only image and a read-write image.
# In the former case (typically an iso), it tries to make a union mount if possible.
# In the latter case, the root image could be mounted and then directly booted up.
mount_and_boot() {
mkdir $ROOT_MOUNT
mknod /dev/loop0 b 7 0 2>/dev/null
if ! mount -o rw,loop,noatime,nodiratime /run/media/$ROOT_DISK/$ISOLINUX/$ROOT_IMAGE $ROOT_MOUNT ; then
fatal "Could not mount rootfs image"
fi
if touch $ROOT_MOUNT/bin 2>/dev/null; then
# The root image is read-write, directly boot it up.
boot_live_root
fi
# determine which unification filesystem to use
union_fs_type=""
if grep -q -w "overlayfs" /proc/filesystems; then
union_fs_type="overlayfs"
elif grep -q -w "aufs" /proc/filesystems; then
union_fs_type="aufs"
else
union_fs_type=""
fi
# make a union mount if possible
case $union_fs_type in
"overlayfs")
mkdir -p /rootfs.ro /rootfs.rw
if ! mount -n --move $ROOT_MOUNT /rootfs.ro; then
rm -rf /rootfs.ro /rootfs.rw
fatal "Could not move rootfs mount point"
else
mount -t tmpfs -o rw,noatime,mode=755 tmpfs /rootfs.rw
mount -t overlayfs -o "lowerdir=/rootfs.ro,upperdir=/rootfs.rw" overlayfs $ROOT_MOUNT
mkdir -p $ROOT_MOUNT/rootfs.ro $ROOT_MOUNT/rootfs.rw
mount --move /rootfs.ro $ROOT_MOUNT/rootfs.ro
mount --move /rootfs.rw $ROOT_MOUNT/rootfs.rw
fi
;;
"aufs")
mkdir -p /rootfs.ro /rootfs.rw
if ! mount -n --move $ROOT_MOUNT /rootfs.ro; then
rm -rf /rootfs.ro /rootfs.rw
fatal "Could not move rootfs mount point"
else
mount -t tmpfs -o rw,noatime,mode=755 tmpfs /rootfs.rw
mount -t aufs -o "dirs=/rootfs.rw=rw:/rootfs.ro=ro" aufs $ROOT_MOUNT
mkdir -p $ROOT_MOUNT/rootfs.ro $ROOT_MOUNT/rootfs.rw
mount --move /rootfs.ro $ROOT_MOUNT/rootfs.ro
mount --move /rootfs.rw $ROOT_MOUNT/rootfs.rw
fi
;;
"")
mount -t tmpfs -o rw,noatime,mode=755 tmpfs $ROOT_MOUNT/media
;;
esac
# boot the image
boot_live_root
}
case $label in
boot)
mount_and_boot
;;
install|install-efi)
if [ -f /run/media/$i/$ISOLINUX/$ROOT_IMAGE ] ; then
./$label.sh $i/$ISOLINUX $ROOT_IMAGE $video_mode $vga_mode $console_params
else
fatal "Could not find $label script"
fi
# If we're getting here, we failed...
fatal "Installation image failed"
;;
*)
# Not sure what boot label is provided. Try to boot to avoid locking up.
mount_and_boot
;;
esac
|
