Remove ssmtp support and add From overwrite option

templates/nullmailer-inject.j2

@@ -0,0 +1,23 @@
+#!/bin/sh
+
+{% if mail.overwrite_from_header %}
+username="$(id -un 2> /dev/null || echo nobody)"
+
+excepted=0
+
+for excepted_user in {% for item in mail.overwrite_from_header_except_users %} {{ item|quote }} {% endfor %}; do
+	if [ "$username" = "$excepted_user" ]; then
+		excepted=1
+		break
+	fi
+done
+
+if [ "$excepted" = "0" ]; then
+	export NULLMAILER_NAME="${username} on $(hostname -f)"
+	export NULLMAILER_USER={{ mail.from.split('@')[0]|quote }}
+	export NULLMAILER_HOST={{ mail.from.split('@', 1)[1]|quote }}
+	export NULLMAILER_FLAGS=f
+fi
+{% endif %}
+
+exec /usr/bin/nullmailer-inject-bin "$@"

templates/smtp.conf.j2

@@ -1,21 +0,0 @@
-#
-# Config file for sSMTP sendmail
-#
-# The person who gets all mail for userids < 1000
-# Make this empty to disable rewriting.
-root={{ mail['root'] }}
-
-# The place where the mail goes. The actual machine name is required no
-# MX records are consulted. Commonly mailhosts are named mail.domain.com
-mailhub={{ mail['server'] }}
-
-# Where will the mail seem to come from?
-rewriteDomain={{ mail['domain'] }}
-
-# The full hostname
-hostname={{ inventory_hostname }}
-
-# Are users allowed to set their own From: address?
-# YES - Allow the user to specify their own From: address
-# NO - Use the system generated From: address
-FromLineOverride=YES