#!/bin/sh
#
# mutt/sendmail – sendmail wrapper to enforce some checks on outgoing mails
#
# The script basically just creates a temporary file and then invokes any
# executable scripts in ~/.mutt/sendmail-checks.d in run-parts style. They
# receive the filename of a temporary file holding the message to be sent as
# $1, followed by all recipients as determined by mutt.
#
# Copyright © 2010 martin f. krafft <madduck@madduck.net>
# Released under the terms of the Artistic Licence 2.0
#
set -eu

CHECKSDIR="$HOME/.mutt/sendmail-checks.d"
SENDMAIL="/usr/sbin/sendmail -oem -oi"

TMPFILE=$(tempfile -p mutt-sendmail -s .msg)
settrap () { trap "$@" 0 1 2 3 4 5 6 7 8 10 11 12 13 14 15; }
cleanup () { rm -f "$TMPFILE"; settrap -; }
settrap cleanup

argtype=s
args= sendmail_args=
for i in "$@"; do
  case "$argtype/$i" in
    (s/--) argtype=r;;
    (s/*) sendmail_args="${sendmail_args} $i";;
    (r/*) args="${args} --arg=$i";;
  esac
done

cat > $TMPFILE
run-parts --umask=0077 --arg="$TMPFILE" $args -- "$CHECKSDIR"
$SENDMAIL "$sendmail_args" < "$TMPFILE"

cleanup