remail: Add remail_pipe script

Add a handle pipe function to the remailer and a pipe script for handling
mail in a MTA delivery path.

Requested-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Documentation/index.rst

@@ -70,6 +70,7 @@ Usage guidelines (man pages)
    :maxdepth: 3
 
    man1/remail_daemon.rst
+   man1/remail_pipe.rst
    man1/remail_chkcfg.rst
    man5/remail.config.rst
   

Documentation/man1/remail_daemon.rst

@@ -14,7 +14,7 @@ Description
 -----------
 
 :program:`remail_daemon`, The daemon for running an encrypted mailing
-list. It reads the configuration file from the command line.
+list. The configuration file name is handed in as command line argument.
 
 
 Options
@@ -36,8 +36,8 @@ Options
 Configuration file
 ------------------
 
-remail_daemon reads the configuration file which was handed in on the
-command line.  The configuration file is a simple yaml file. Non-mandatory
+remail_daemon reads the configuration file which was handed in as command
+line argument.  The configuration file is a simple yaml file. Non-mandatory
 configuration options which are not in the configuration file are set to
 the default values.
 

Documentation/man1/remail_pipe.rst

@@ -0,0 +1,74 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+.. _remail_pipe_man:
+
+remail_pipe manual page
+=========================
+
+Synopsis
+--------
+
+**remail_pipe** [*options*] config_file
+
+Description
+-----------
+
+:program:`remail_pipe`, The pipe script for decrypting incoming mail and
+sending it re-encrypted to the subscribers of an encrypted mailing
+list. The incoming mail is read from stdin.
+
+
+Options
+-------
+
+-h, --help
+   Show this help message and exit
+
+-s syslog, --syslog
+   Use syslog for logging. Default is stderr
+
+-v, --verbose
+   Enable verbose logging.
+
+-V, --version
+   Display version information
+
+
+Configuration file
+------------------
+
+remail_pipe reads the configuration file which was handed in as command
+line argument.  The configuration file is a simple yaml file. Non-mandatory
+configuration options which are not in the configuration file are set to
+the default values.
+
+See the configuration file man page for detailed information.
+
+
+Work directory
+--------------
+
+remail pipe assumes that the configuration file is in the work directory
+which has a defined layout and content. The directory structure is
+documented in the full remail documentation along with hints how to manage
+encrypted mailing lists.
+
+Exit codes
+----------
+
+.. list-table::
+
+   * - 0
+     - Mail was successfully delivered
+   * - 1
+     - No enabled mailinglist found for delivery
+   * - 2
+     - Mail processing incomplete. See log output
+   * - 11
+     - Configuration error
+   * - 12
+     - Fatal exception
+
+See also
+--------
+:manpage:`remail.config(5)`

Documentation/man5/remail.config.rst

@@ -38,7 +38,7 @@ Configuration directory structure
 
 The configuration directory structure is fixed and looks like this::
 
-    ├── .certs
+  ├── .certs
   │   ├── cacert.pem
   │   ├── list1@your.domain.key
   │   ├── list2@your.domain.key
@@ -427,4 +427,5 @@ See also
 --------
 :manpage:`remail_daemon(1)`
 :manpage:`remail_chkcfg(1)`
+:manpage:`remail_pipe(1)`
 

remail/remaild.py

@@ -7,7 +7,7 @@ from remail.config import RemailConfigException
 from remail.config import main_config
 from remail.maillist import maillist
 
-from email import message_from_binary_file
+from email import message_from_binary_file, message_from_file
 from email.policy import EmailPolicy
 from ruamel.yaml import YAML
 import pyinotify
@@ -15,6 +15,7 @@ import mailbox
 import pathlib
 import signal
 import fcntl
+import sys
 import os
 
 class EventHandler(pyinotify.ProcessEvent):
@@ -173,6 +174,25 @@ class remaild(object):
         except:
             pass
 
+
+    def process_msg(self, msg):
+        # Check whether one of the lists will take it
+        for ml in self.mailinglists:
+            if not ml.enabled:
+                continue
+            dest = ml.get_destination(msg)
+            if not dest:
+                continue
+            try:
+                if ml.process_mail(msg, dest):
+                    return 0
+                return 2
+            except Exception as ex:
+                txt = 'Failed to process mail file %s\n' %(mailfile)
+                self.logger.log_exception(txt, ex)
+                break
+        return 1
+
     # The actual mail processing
     def process_mail(self, queue):
         '''
@@ -193,24 +213,9 @@ class remaild(object):
                 self.logger.log_exception(txt, ex)
                 continue
 
-            # Check whether one of the lists will take it
-            processed = False
-            for ml in self.mailinglists:
-                if not ml.enabled:
-                    continue
-                dest = ml.get_destination(msg)
-                if not dest:
-                    continue
-                try:
-                    processed = ml.process_mail(msg, dest)
-                    break
-                except Exception as ex:
-                    self.failedmails.append(mailfile)
-                    txt = 'Failed to process mail file %s\n' %(mailfile)
-                    self.logger.log_exception(txt, ex)
-                    break
+            res = self.process_msg(msg)
 
-            if processed:
+            if res == 0:
                 os.unlink(mailfile)
             else:
                 self.move_frozen(mailfile)
@@ -360,6 +365,17 @@ class remaild(object):
 
         return self.should_stop()
 
+    # The pipe handling interface
+    def handle_pipe(self):
+        self._should_reload = True
+        self.reconfigure()
+
+        if not self.enabled:
+            return 1
+
+        msg = message_from_file(sys.stdin)
+        return self.process_msg(msg)
+
     # The runner
     def run(self):
 

remail_pipe

@@ -0,0 +1,57 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0-only
+# Copyright Thomas Gleixner <tglx@linutronix.de>
+#
+
+from remail.utils import logger
+from remail.version import __version__
+from remail.remaild import remaild
+
+from argparse import ArgumentParser
+
+import sys
+import os
+
+def exit_daemon(logger, res):
+    logger.log('Stopped\n')
+    sys.exit(res)
+
+if __name__ == '__main__':
+    parser = ArgumentParser(description='remail pipe')
+    parser.add_argument('config', help='Config file')
+    parser.add_argument('--syslog', '-s', dest='syslog', action='store_true',
+                        help='Use syslog for logging. Default is stderr')
+    parser.add_argument('--verbose', '-v', dest='verbose', action='store_true',
+                        help='Verbose logging')
+    parser.add_argument('--version', '-V', action='version',
+                        version='%(prog)s {version}'.format(version=__version__))
+    args = parser.parse_args()
+
+    logger = logger(use_syslog=args.syslog, verbose=args.verbose)
+    logger.log("Started\n")
+
+    # Change into the directory in which the config file resides
+    wdir = os.path.dirname(args.config)
+    if len(wdir):
+        os.chdir(wdir)
+        args.config = os.path.basename(args.config)
+
+    try:
+        rd = remaild(args.config, logger)
+    except Exception as ex:
+        '''
+        Exceptions which reach here are fatal
+        '''
+        logger.log_exception('', ex, verbose=True)
+        exit_daemon(logger, 11)
+
+    try:
+        res = rd.handle_pipe()
+    except Exception as ex:
+        '''
+        Exceptions which reach here are fatal
+        '''
+        logger.log_exception('', ex, verbose=True)
+        res = 12
+
+    exit_daemon(logger, res)