#!/bin/sh
# Copyright © 2005-2009  Roger Leigh <rleigh@debian.org>
# Copyright © 2009       Jan-Marek Glogowski <glogow@fbihome.de>
#
# schroot is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# schroot is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see
# <http://www.gnu.org/licenses/>.
#
#####################################################################

set -e

. "$SETUP_DATA_DIR/common-data"
. "$SETUP_DATA_DIR/common-functions"

if [ -f "$CHROOT_SCRIPT_CONFIG" ]; then
    . "$CHROOT_SCRIPT_CONFIG"
elif [ "$STATUS" = "ok" ]; then
    fatal "script-config file '$CHROOT_SCRIPT_CONFIG' does not exist"
fi

# Mount a filesystem
# $1: mount options
# $2: mount device
# $3: mount location
do_mount()
{
    info "Mounting $2 on $3"

    if [ ! -d "$3" ]; then
	mkdir -p "$3"
    fi
    if [ ! -d "$3" ]; then
	fatal "$3 does not exist, and could not be created"
    fi

    info "$MOUNT_VERBOSE $1 $2 $3"
    mount $MOUNT_VERBOSE $1 "$2" "$3"
}

# Unmount all filesystems under specified location
# $1: mount base location
do_umount_all()
{
    if [ -d "$1" ]; then
	# Note that flock is used here to prevent races reading
	# /proc/mounts, which on current (Linux 2.6.32) kernels is
	# racy.  If other processes are mounting or unmounting
	# filesystems as we read it, we can miss mount entries due to
	# the file changing as we read it.  This needs fixing in the
	# kernel, but an exclusive lock surrounding the
	# schroot-listmounts invocation is a partial fix.  This
	# prevents racing when multiple schroot processes are running.
	# Note that this does not prevent the problem when programs
	# other than schroot mount and unmount filesystems (since they
	# don't create the lock).
	( flock 9
	    mounts="$("$LIBEXEC_DIR/schroot-listmounts" -m "$1")"
	    if [ "x$mounts" != 'x' ]; then
		echo "$mounts" |
		while read mountloc; do
                    info "Unmounting $mountloc"
		    umount "$mountloc" || exit 1
		done || exit 1
	    fi
	) 9>"/var/lock/schroot-umount"
    else
	warn "Mount location $1 no longer exists; skipping unmount"
    fi
}

# Mount a filesystem union
# $1: the mount location
do_mount_fs_union()
{
    # Prepare mount options (branch config) for union type
    if [ -z "$CHROOT_UNION_MOUNT_OPTIONS" ]; then
	case $CHROOT_UNION_TYPE in
	    unionfs)
		CHROOT_UNION_MOUNT_OPTIONS="dirs=${CHROOT_UNION_OVERLAY_DIRECTORY}=rw,${CHROOT_UNION_UNDERLAY_DIRECTORY}=ro"
		;;
	    aufs)
		CHROOT_UNION_MOUNT_OPTIONS="br:${CHROOT_UNION_OVERLAY_DIRECTORY}:${CHROOT_UNION_UNDERLAY_DIRECTORY}=ro"
		;;
	esac
    fi

    info "Using '$CHROOT_UNION_TYPE' for filesystem union"

    # Try mounting fs
    mount -t "$CHROOT_UNION_TYPE" -o "$CHROOT_UNION_MOUNT_OPTIONS" "$CHROOT_NAME" "$1"
}

if [ "$VERBOSE" = "verbose" ]; then
    MOUNT_VERBOSE="-v"
#  FSCK_VERBOSE="-V"
fi

if [ "$CHROOT_TYPE" = "directory" ] \
    || [ "$CHROOT_TYPE" = "file" ] \
    || [ "$CHROOT_TYPE" = "loopback" ] \
    || [ "$CHROOT_TYPE" = "block-device" ] \
    || [ "$CHROOT_TYPE" = "lvm-snapshot" ] \
    || [ "$CHROOT_TYPE" = "btrfs-snapshot" ]; then

    if [ "${CHROOT_UNION_TYPE:-none}" != "none" ]; then
	CREATE_UNION="yes"
    else
	CREATE_UNION="no"
    fi

    if [ $STAGE = "setup-start" ] || [ $STAGE = "setup-recover" ]; then

	case "$HOST_OS" in
	    freebsd* | k*bsd*-gnu) :
		BINDOPT="-t nullfs"
		;;
	    *):
		BINDOPT="--bind"
		;;
	esac

	if [ "$CHROOT_TYPE" = "directory" ]; then
	    CHROOT_MOUNT_OPTIONS="$BINDOPT $CHROOT_MOUNT_OPTIONS"
	    CHROOT_MOUNT_DEVICE="$CHROOT_DIRECTORY"
	    if [ ! -d "$CHROOT_DIRECTORY" ]; then
		fatal "Directory '$CHROOT_DIRECTORY' does not exist"
	    fi
	elif [ "$CHROOT_TYPE" = "file" ]; then
	    CHROOT_MOUNT_OPTIONS="$BINDOPT $CHROOT_MOUNT_OPTIONS"
	    CHROOT_MOUNT_DEVICE="${CHROOT_FILE_UNPACK_DIR}/${SESSION_ID}"
	elif [ "$CHROOT_TYPE" = "block-device" ]; then
	    if [ ! "$DEVTYPE" "$CHROOT_DEVICE" ]; then
		fatal "Device '$CHROOT_DEVICE' does not exist"
	    fi
	elif [ "$CHROOT_TYPE" = "btrfs-snapshot" ]; then
	    CHROOT_MOUNT_OPTIONS="$BINDOPT $CHROOT_MOUNT_OPTIONS"
	    CHROOT_MOUNT_DEVICE="$CHROOT_BTRFS_SNAPSHOT_NAME"
	elif [ "$CHROOT_TYPE" = "loopback" ]; then
	    if [ ! -f "$CHROOT_FILE" ]; then
	    	fatal "File '$CHROOT_FILE' does not exist"
	    fi

	    case "$HOST_OS" in
		freebsd* | k*bsd*-gnu):
		    LOOP_DEVICE="/dev/$(/sbin/mdconfig -a -t vnode -f "$CHROOT_FILE")"
		    CHROOT_MOUNT_DEVICE="$LOOP_DEVICE"
		    ;;
		*):
		    LOOP_DEVICE="$(/sbin/losetup -j "$CHROOT_FILE" | sed -e 's/:.*$//')"
		    if [ -z "$LOOP_DEVICE" ]; then
			CHROOT_MOUNT_DEVICE="$CHROOT_FILE"
			CHROOT_MOUNT_OPTIONS="-o loop $CHROOT_MOUNT_OPTIONS"
		    else
			CHROOT_MOUNT_DEVICE="$LOOP_DEVICE"
		    fi
		    ;;
	    esac
	fi

        if [ ! -d "$CHROOT_MOUNT_LOCATION" ]; then
	    mkdir -p "$CHROOT_MOUNT_LOCATION"
        fi
	if [ ! -d "$CHROOT_MOUNT_LOCATION" ]; then
	    fatal "$CHROOT_MOUNT_LOCATION does not exist, and could not be created"
	fi

	# If recovering, we want to remount all filesystems to ensure
	# a sane state.
	if [ $STAGE = "setup-recover" ]; then
	    if [ "$CREATE_UNION" = "yes" ]; then
		do_umount_all "$CHROOT_UNION_UNDERLAY_DIRECTORY"
	    fi
	    do_umount_all "$CHROOT_MOUNT_LOCATION"
	fi

	if [ "$CREATE_UNION" = "yes" ]; then
	    do_mount "$CHROOT_MOUNT_OPTIONS" "$CHROOT_MOUNT_DEVICE" "$CHROOT_UNION_UNDERLAY_DIRECTORY"
	    do_mount_fs_union "$CHROOT_MOUNT_LOCATION"
	else
	    do_mount "$CHROOT_MOUNT_OPTIONS" "$CHROOT_MOUNT_DEVICE" "$CHROOT_MOUNT_LOCATION"
	fi

	if [ -n "$FSTAB" ]; then
	    if [ -f "$FSTAB" ]; then
		"$LIBEXEC_DIR/schroot-mount" $MOUNT_VERBOSE \
		    -f "$FSTAB" -m "$CHROOT_PATH"
	    else
		fatal "fstab file '$FSTAB' does not exist"
	    fi
	fi

    elif [ $STAGE = "setup-stop" ]; then

	do_umount_all "$CHROOT_MOUNT_LOCATION"
	if [ "$CREATE_UNION" = "yes" ]; then
	    do_umount_all "$CHROOT_UNION_UNDERLAY_DIRECTORY"
	fi

	# Purge mount location.
	# The contents of file chroots are purged separately, because
	# we might want to repack the contents.
	if echo "$CHROOT_MOUNT_LOCATION" | grep -q "^$MOUNT_DIR/"; then
	    if [ -d "$CHROOT_MOUNT_LOCATION" ]; then
		rmdir "$CHROOT_MOUNT_LOCATION"
	    fi
	fi

    fi

fi

