How to mount a Truecrypt container with a timeout from the command line?

Question

I'm mounting a truecrypt container via the command line (i.e. truecrypt file dir). Is there any way to have truecrypt automatically unmount the container after a given amount of inactivity in dir?

Answer 1

Truecrypt can't do this but something like the following would accomplish what you are trying to do:

#!/bin/bash
TIMEOUT_PERIOD_IN_MINUTES=60

cd /
sleep ${TIMEOUT_PERIOD_IN_MINUTES}m
echo "$0: Proceeding with dismount in 5 minutes." > /dev/console
# or something else to notify user that the volume will be unmounted
sleep 4.5m
echo "$0: Proceeding with dismount in 30 seconds." > /dev/console
sleep 30s
sync; truecrypt $@

The cd / would be to ensure that the current directory is never within the mounted truecrypt volume, just in case you invoked it under different circumstances.

Save this somewhere, chmod +x it, and call it something like truecrypt-auto-dismount, and then

truecrypt {mount-options}; truecrypt-auto-dismount {dismount-options}

I would definitely incorporate some type of notification so you have a chance to close open files. Of course you could get rather elaborate and try to incorporate a loop that kills with SIGTERM (and then does SIGKILL if it doesn't respond in a timeframe) all processes listed by lsof | grep /mnt/your-truecrypt-volume if you wanted.