Remove ssmtp support and add From overwrite option

defaults/main.yml

@@ -1,5 +1,8 @@
 mail:
+  from: "noreply@example.com"
+  overwrite_from_envelope: no
+  overwrite_from_header: no
+  overwrite_from_header_except_users: []
   root: "root@example.com"
   server: "mail.example.com"
   domain: "example.com"
-  backend: nullmailer

tasks/main.yml

@@ -1,6 +1,37 @@
-- include_tasks: ssmtp.yml
-  when:
-  - ansible_distribution_release == "stretch"
-  - mail.backend == "ssmtp"
-- include_tasks: nullmailer.yml
-  when: (ansible_distribution_release != "stretch" or mail.backend != "ssmtp")
+- name: install nullmailer
+  apt:
+    pkg: nullmailer
+
+- name: divert nullmailer-inject
+  community.general.dpkg_divert:
+    path: /usr/bin/nullmailer-inject
+    divert: /usr/bin/nullmailer-inject-bin
+    rename: yes
+
+- name: create nullmailer-inject wrapper script
+  template:
+    src: nullmailer-inject.j2
+    dest: /usr/bin/nullmailer-inject
+    mode: 0755
+
+- name: setup nullmailer envelope from overwrite
+  copy:
+    dest: "/etc/nullmailer/allmailfrom"
+    mode: "0644"
+    owner: root
+    group: root
+    content: "{{ mail.from if mail.overwrite_from_envelope else '' }}"
+
+- name: setup nullmailer
+  notify: restart nullmailer
+  copy:
+    dest: "{{ item.dest }}"
+    content: "{{ item.content }}"
+    owner: "{{ item.owner }}"
+    group: "{{ item.group }}"
+    mode: "{{ item.mode }}"
+  with_items:
+  - {dest: "/etc/nullmailer/adminaddr",     mode: "0644", owner: root, group: root, content: "{{ mail.root }}"}
+  - {dest: "/etc/nullmailer/remotes",       mode: "0600", owner: mail, group: mail, content: "{{ mail.server }}"}
+  - {dest: "/etc/nullmailer/defaultdomain", mode: "0644", owner: root, group: root, content: "{{ mail.domain }}"}
+  - {dest: "/etc/mailname", mode: "0644", owner: root, group: root, content: "{{ inventory_hostname }}\n"}

tasks/nullmailer.yml

@@ -1,27 +0,0 @@
-- name: install nullmailer
-  apt:
-    pkg: nullmailer
-
-- name: remove ssmtp
-  apt:
-    pkg: ssmtp
-    state: absent
-
-- name: remove ssmtp config
-  file:
-    path: /etc/ssmtp/ssmtp.conf
-    state: absent
-
-- name: setup nullmailer
-  notify: restart nullmailer
-  copy:
-    dest: "{{ item.dest }}"
-    content: "{{ item.content }}"
-    owner: "{{ item.owner }}"
-    group: "{{ item.group }}"
-    mode: "{{ item.mode }}"
-  with_items:
-  - {dest: "/etc/nullmailer/adminaddr",     mode: "0644", owner: root, group: root, content: "{{ mail.root }}"}
-  - {dest: "/etc/nullmailer/remotes",       mode: "0600", owner: mail, group: mail, content: "{{ mail.server }}"}
-  - {dest: "/etc/nullmailer/defaultdomain", mode: "0644", owner: root, group: root, content: "{{ mail.domain }}"}
-  - {dest: "/etc/mailname", mode: "0644", owner: root, group: root, content: "{{ inventory_hostname }}\n"}

tasks/ssmtp.yml

@@ -1,9 +0,0 @@
-- name: install ssmtp
-  apt:
-    pkg: ssmtp
-
-- name: setup ssmtp
-  template:
-    src: smtp.conf.j2
-    dest: /etc/ssmtp/ssmtp.conf
-    mode: 0600

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