gpg-agent-helpers

gpg-helpers.sh

#!/bin/sh

# The current agent term is managed through the TTY_SET_FILE which only 
# contains the name of the term currently responsible for handling all gpg
# UI stuff.

# Prior to setting up a term to function as the front-end to GPG-Agent one 
# needs to get the agent started first

# The tty currently active as GPG-Agent front-end
TTY_SET_FILE=/tmp/.gpg-tty-set

# The GPG-Agent info file
AGENT_INFO_FILE=/tmp/.gpg-agent-info

# Make the current terminal the agent terminal if the GPG-Agent is running and
# there is no terminal currently configured as the agent front-end
make-gpg-tty() {
  if [ -f "$AGENT_INFO_FILE" ]; then
    if [ -f "$TTY_SET_FILE" ]; then
      if [[ $(tty) == $(cat $TTY_SET_FILE) ]]; then
        echo "I already am: $(cat $TTY_SET_FILE)"
      else
        echo "there already is a tty set to handle gpg interactions: $(cat $TTY_SET_FILE)"
      fi
    else
      GPG_TTY=$(tty);
      export GPG_TTY
      echo "tty is currenty $(tty)"

      . "$AGENT_INFO_FILE"
      export GPG_AGENT_INFO
      export SSH_AUTH_SOCK
      echo $(tty) > "$TTY_SET_FILE"
    fi
  else
    echo "No gpg agent info file found. Run start-gpg-agent first.";
  fi
}

# Unmake the current terminal the agent term
unmake-gpg-tty() {
  unset GPG_AGENT_INFO
  unset SSH_AUTH_SOCK
  unset SSH_AGENT_PID
  unset GPG_TTY
  if [ -f "$TTY_SET_FILE" ]; then
    if [[ $(tty) == $(cat $TTY_SET_FILE) ]]; then
      rm $TTY_SET_FILE
      echo "this tty is no longer the gpg term"
    fi
  fi
}

# Display some interesting information. Especially if executed in the GPG-Agent
# frontend term
view-gpg-tty() {
  echo "info: $GPG_AGENT_INFO"
  echo "sock: $SSH_AUTH_SOCK"
  echo "pid: $SSH_AGENT_PID"
  echo "tty: $GPG_TTY"
}

# Start the GPG-Agent and keep track of the agent details in a publically 
# accessible file
start-gpg-agent() {
  if [ -f "$AGENT_INFO_FILE" ]; then
    echo "agent info already exist";
  else
    echo "agent info does not exist";
    gpg-agent --daemon --enable-ssh-support --write-env-file "$AGENT_INFO_FILE"
  fi
}

# Stop the GPG-Agent
stop-gpg-agent() {
  if [ -f "$AGENT_INFO_FILE" ]; then
    source $AGENT_INFO_FILE
    echo "agent is $SSH_AGENT_PID"
    kill -9 $SSH_AGENT_PID
    rm $AGENT_INFO_FILE
  else
  fi
}