move management into a daemon service running as root

* Created a new Python/flask-based management daemon.
* Moved the mail user management core code from tools/mail.py to the new daemon.
* tools/mail.py is a wrapper around the daemon and can be run as a non-root user.
* Adding a new initscript for the management daemon.
* Moving dns_update.sh to the management daemon, called via curl'ing the daemon's API.

This also now runs the DNS update after mail users and aliases are added/removed,
which sets up new domains' DNS as needed.

management/mailconfig.py

@@ -0,0 +1,111 @@
+import subprocess, shutil, os, sqlite3, re
+
+def open_database(env, with_connection=False):
+	conn = sqlite3.connect(env["STORAGE_ROOT"] + "/mail/users.sqlite")
+	if not with_connection:
+		return conn.cursor()
+	else:
+		return conn, conn.cursor()
+
+def get_mail_users(env):
+	c = open_database(env)
+	c.execute('SELECT email FROM users')
+	return [row[0] for row in c.fetchall()]
+
+def get_mail_aliases(env):
+	c = open_database(env)
+	c.execute('SELECT source, destination FROM aliases')
+	return [(row[0], row[1]) for row in c.fetchall()]
+
+def get_mail_domains(env):
+	def get_domain(emailaddr):
+		return emailaddr.split('@', 1)[1]
+	return set([get_domain(addr) for addr in get_mail_users(env)] + [get_domain(addr1) for addr1, addr2 in get_mail_aliases(env)])
+
+def add_mail_user(email, pw, env):
+	if not re.match("\w[\w\.]+@\w[\w\.]+$", email):
+		return ("Invalid email address.", 400)
+
+	# get the database
+	conn, c = open_database(env, with_connection=True)
+
+	# hash the password
+	pw = subprocess.check_output(["/usr/bin/doveadm", "pw", "-s", "SHA512-CRYPT", "-p", pw]).strip()
+
+	# add the user to the database
+	try:
+		c.execute("INSERT INTO users (email, password) VALUES (?, ?)", (email, pw))
+	except sqlite3.IntegrityError:
+		return ("User already exists.", 400)
+		
+	# write databasebefore next step
+	conn.commit()
+
+	# Create the user's INBOX and Spam folders and subscribe them.
+
+	# Check if the mailboxes exist before creating them. When creating a user that had previously
+	# been deleted, the mailboxes will still exist because they are still on disk.
+	existing_mboxes = subprocess.check_output(["doveadm", "mailbox", "list", "-u", email, "-8"]).decode("utf8").split("\n")
+
+	if "INBOX" not in existing_mboxes: subprocess.check_call(["doveadm", "mailbox", "create", "-u", email, "-s", "INBOX"])
+	if "Spam" not in existing_mboxes: subprocess.check_call(["doveadm", "mailbox", "create", "-u", email, "-s", "Spam"])
+
+	# Create the user's sieve script to move spam into the Spam folder, and make it owned by mail.
+	maildirstat = os.stat(env["STORAGE_ROOT"] + "/mail/mailboxes")
+	(em_user, em_domain) = email.split("@", 1)
+	user_mail_dir = env["STORAGE_ROOT"] + ("/mail/mailboxes/%s/%s" % (em_domain, em_user))
+	if not os.path.exists(user_mail_dir):
+		os.makedirs(user_mail_dir)
+		os.chown(user_mail_dir, maildirstat.st_uid, maildirstat.st_gid)
+	shutil.copyfile(env["CONF_DIR"] + "/dovecot_sieve.txt", user_mail_dir + "/.dovecot.sieve")
+	os.chown(user_mail_dir + "/.dovecot.sieve", maildirstat.st_uid, maildirstat.st_gid)
+
+	# Update DNS in case any new domains are added.
+	from dns_update import do_dns_update
+	return do_dns_update(env)
+
+def set_mail_password(email, pw, env):
+	# hash the password
+	pw = subprocess.check_output(["/usr/bin/doveadm", "pw", "-s", "SHA512-CRYPT", "-p", pw]).strip()
+
+	# update the database
+	conn, c = open_database(env, with_connection=True)
+	c.execute("UPDATE users SET password=? WHERE email=?", (pw, email))
+	if c.rowcount != 1:
+		return ("That's not a user (%s)." % email, 400)
+	conn.commit()
+	return "OK"
+
+def remove_mail_user(email, env):
+	conn, c = open_database(env, with_connection=True)
+	c.execute("DELETE FROM users WHERE email=?", (email,))
+	if c.rowcount != 1:
+		return ("That's not a user (%s)." % email, 400)
+	conn.commit()
+
+	# Update DNS in case any domains are removed.
+	from dns_update import do_dns_update
+	return do_dns_update(env)
+
+def add_mail_alias(source, destination, env):
+	conn, c = open_database(env, with_connection=True)
+	try:
+		c.execute("INSERT INTO aliases (source, destination) VALUES (?, ?)", (source, destination))
+	except sqlite3.IntegrityError:
+		return ("Alias already exists (%s)." % source, 400)
+	conn.commit()
+
+	# Update DNS in case any new domains are added.
+	from dns_update import do_dns_update
+	return do_dns_update(env)
+
+def remove_mail_alias(source, env):
+	conn, c = open_database(env, with_connection=True)
+	c.execute("DELETE FROM aliases WHERE source=?", (source,))
+	if c.rowcount != 1:
+		return ("That's not an alias (%s)." % source, 400)
+	conn.commit()
+
+	# Update DNS in case any domains are removed.
+	from dns_update import do_dns_update
+	return do_dns_update(env)