Accepting Input With Non-Interactive Shell

scorchgeek · 11-21-2011, 09:47 PM

Here's an interesting problem, and I have a feeling the solution will be changing the way I'm going about things.

I have a flash drive. When I plug in this drive, I want:
* My KeePass password database to be synchronized to it.
* The computer to mount my TrueCrypt volume using the password AND the keyfile which is stored on the flash drive. (The actual volume is stored on my hard drive.)

I have created a script that mounts the flash drive and synchronizes the password database, and set it to be triggered via udev. That part works great--plug in flash drive, database synchronized.

What doesn't work so well is the TrueCrypt part. TC has great command-line support, but the password prompt can't accept my password because when udev runs the script, it's in a non-interactive shell. (I could put the password on the command line in the script, but then that would circumvent the whole point of having a memorized password in the first place.)

So my first question is, is there any way I can possibly execute a command interactively, when the command is started automatically from a non-interactive shell? My second question is, is there another way I could accomplish all this that would let me do that (short of double-clicking the script when I plugged in the drive)? The only way I could think of is using cron or such to check if the drive is plugged in every so often, which would still suffer from the same problem.

EDIT: I'm using Ubuntu 11.04, if that matters at all.

scorchgeek · 11-21-2011, 10:03 PM

Funnily enough, I found something applicable in the very next forum thread:
http://www.linuxquestions.org/questi...essage-914621/

After looking at zenity for a little while, this seems perfect. Bizarrely, however, it fails to work in my script.

Code:

export DISPLAY=:0.0
zenity --question

This does nothing. Running the same two lines in an at job works fine, though. The entry in my /etc/udev/rules.d/10-local.rules is:

Code:

ACTION=="add", KERNEL=="sd?1", ATTRS(idVendor)=="058f", ATTRS{idProduct}=="6387", RUN+="[path]/syncflash.sh"

The script runs fine. I just can't get that darned message box to appear.

scorchgeek · 11-21-2011, 10:37 PM

And now I have the following:

Code:

export DISPLAY=:0.0
sudo -u [username] zenity --info --text="hello"
password=$(sudo -u [username] zenity --password)
truecrypt --mount [ARCHIVE_LOCATION] /media/truecrypt1 -k [KEYFILE_LOCATION] -p="$password"

Here the info box appears as it should, the password box appears as it should, but for some reason TrueCrypt refuses to mount the volume. The script is being run as root (truecrypt needs to be run as root), and the password is correct. (Also tried putting the zenity password in the -p with $(); that didn't work either.)

Is there something obvious I'm missing?