# Hey, Emacs, this is -*- sh -*- code
#       Copyright (c) 1999 Tim Barbour. All Rights Reserved.
#       This script may be used and distributed under the terms
#       of the GNU GPL, as published by the Free Software Foundation.

# these functions provide low-level services to cdpio

# Common functions for backup purposes

# not very low-level, but needed by dump-cdr-image, temporarily at least
ask_user_action() {
    cat /dev/null > $volume_change_mail_spool
    echo "$2" \
       | mail  -a "From: $volume_change_user" -a "Reply-To: $volume_change_user" -s "$1" $backup_operator
    until [ -n "`cat $volume_change_mail_spool`" ]; do
        sleep 10
    done
}

is_mounted() {
   if(mount | grep $1 > /dev/null); then
      true
   else
      false
   fi
}

make_unmounted() {
   if(is_mounted $1); then
       umount $1
   fi
}

# find the image or device for the supplied filesystem ($1)
# if the filesystem_image variable is set, use that
# otherwise work it out from /etc/fstab
find_fs_image() {
    if [ -n "$image" ]; then
	echo $image
    elif !(grep -v '^#' /etc/fstab | grep $1 - > /dev/null); then
	exit -1
    else
	grep -v '^#' /etc/fstab | grep $1 - | awk '{print $1;}'
    fi
}

find_free_loop_device() {
    for x in `ls /dev/loop/*`; do
	if(losetup $x 2>&1 | grep -i "no such device" > /dev/null); then
	    # this loop device is free
	    echo $x
	    return
	fi
    done
    # no free loop devices, give up
    exit -1
}

is_device() {
   if(echo $1 | egrep "^/dev/.+" > /dev/null); then
      true
   else
      false
   fi
}

# init_backup_fs image blocks mount_point label compression
init_backup_fs() {
    make_unmounted $3
    device=""
    should_release=""
    if(is_device $1); then
        device=$1
    else
	# must be an image file, so we need to use a loop device
	device=`find_free_loop_device`
	losetup $device $1
	should_release="yes"
    fi
    /sbin/mke2fs -m 0 -q -L $4 $device $2
    if [ -n "$should_release" ]; then
	losetup -d $device
    fi
    mount $3
    if [ -n "$5" ]; then
        # turn on ext2 compression
	chattr -m $5 $3
	chattr +c $3
    fi
}