linuxkit/pkg/losetup/loopy.sh
Christian Wuerdig 8cd16c4904 Adding losetup utility package to core pkg
Signed-off-by: Christian Wuerdig <christian.wuerdig@gmail.com>
2019-01-14 06:24:00 +13:00

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#!/bin/sh
set -e
help()
{
echo "Usage: $0 [options] <file>"
echo
echo "Options:"
echo " -c, --create Create <file> if not present, default: false"
echo " -s, --size NUM Size of <file> in MiB if it gets created, default: 10"
echo " -d, --dev DEVICE Use DEVICE as loop device, default: /dev/loop0"
echo
}
create=false
size_mib=10
loop_device="/dev/loop0"
O=`getopt -l create,size:,dev:,help -- cs:d:h "$@"` || exit 1
eval set -- "$O"
while true; do
case "$1" in
-c|--create) create=true; shift;;
-s|--size) size_mib=$2; shift 2;;
-d|--dev) loop_device=$2; shift 2;;
-h|--help) help; exit 0;;
--) shift; break;;
*) echo "Unknown option $1"; help; exit 1;;
esac
done
if [ -z "$1" ]; then
echo "Missing argument <file>"
help
exit 1
fi
container_file=$1
if [ ! -b "$loop_device" ]; then
echo "Loop device $loop_device doesn't exist! Did you forget to bind-mount '/dev'?"
exit 2
fi
if [ ! -f "$container_file" ]; then
if [ $create = true ]; then
echo "File $container_file not found, creating new one of size $size_mib MiB"
dd if="/dev/zero" of="$container_file" bs=1M count=$size_mib
else
echo "File $container_file not found. Please specify --create or ensure it's present."
exit 2
fi
fi
echo "Associating file $container_file with loop device $loop_device"
losetup "$loop_device" "$container_file"