#!/bin/bash

LOCKDIR="/tmp/snapshotslocks/"

[ ! -d "$LOCKDIR" ] && mkdir -p "$LOCKDIR"

createlock() {
    LOCKNAME=$1
    [ -f "$LOCKDIR/$LOCKNAME.lock" ] && exit 1
    touch "$LOCKDIR/$LOCKNAME.lock"
    exit 0
}

deletelock() {
    LOCKNAME=$1
    [ ! -f "$LOCKDIR/$LOCKNAME.lock" ] && exit 1
    rm "$LOCKDIR/$LOCKNAME.lock"
    exit 0
}

haslock() {
    if ls $LOCKDIR/* 1> /dev/null 2>&1; then
        exit 0
    else
        exit 1
    fi
}

case $1 in
    lock)
        createlock $2
        ;;
    unlock)
        deletelock $2
        ;;
    haslock)
        haslock
        ;;
    show)
        ls $LOCKDIR
        ;;
    *)
        echo "What is $1" >&2
        exit 1
esac