• Pigeonhole
• Sieve
• Plugins
• Pipe

Pigeonhole Sieve Pipe Plugin

The sieve_pipe plugin adds the vnd.dovecot.pipe extension to the Sieve language. The extension adds a new action command for piping messages to a pre-defined set of external programs. To mitigate the security concerns, the external programs cannot be chosen arbitrarily; the available programs are restricted through administrator configuration.

This plugin is available for Pigeonhole v0.2. This plugin is superseded by the Extprograms plugin for Pigeonhole v0.3 and beyond.

Getting the sources

Currently, the sources of the sieve_pipe plugin are not released, but you can get them from the the Mercurial repository:

hg clone  http://hg.rename-it.nl/pigeonhole-0.2-sieve-pipe/

Compiling

If you downloaded the sources of this plugin using Mercurial, you will need to execute ./autogen.sh first to build the automake structure in your source tree. This process requires autotools and libtool to be installed.

If you installed Dovecot from sources, the plugin's configure script should be able to find the installed dovecot-config automatically, along with the Pigeonhole development headers:

./configure
make
sudo make install

If this doesn't work, you can use --with-dovecot=<path> configure option, where the path points to a directory containing dovecot-config file. This can point to an installed file:

./configure --with-dovecot=/usr/local/lib/dovecot
make
sudo make install

The above example should also find the necessary Pigeonhole development headers implicitly. You can also compile by pointing to compiled Dovecot and Pigeonhole source trees:

./configure --with-dovecot=../dovecot-2.0.0/ --with-pigeonhole=../dovecot-2.0-pigeonhole-0.2.0
make
sudo make install

Configuration

This package builds and installs the sieve_pipe plugin for Pigeonhole Sieve. The plugin is activated by adding it to the sieve_plugins setting:

sieve_plugins = sieve_pipe

The plugin can directly pipe a message to an external program (typically a shell script) by forking a new process. Alternatively, it can connect to a Unix socket behind which a Dovecot script service is listening to start the external program, e.g. to execute as a different user or for added security.

The program name specified for the Sieve "pipe" command is used to find the program or socket in a configured directory. Separate directories are specified for the sockets and the directly executed binaries. The socket directory is searched first. Since the Sieve "pipe" command refuses "/" in program names, it is not possible to build a hierarchical structure.

Directly forked programs are executed with a limited set of environment variables: HOME, USER, SENDER, RECIPIENT and ORIG_RECIPIENT. Programs executed through the script-pipe socket service currently have no environment set at all.

The following configuration settings are used by the sieve_pipe plugin:

sieve_pipe_socket_dir =

Points to a directory relative to the Dovecot base_dir where the sieve_pipe plugin looks for the sockets.

sieve_pipe_bin_dir =

Points to a directory where the sieve_pipe plugin looks for programs (shell scripts) to execute directly and pipe messages to.

Example of socket service

plugin {
  sieve = ~/.dovecot.sieve

  sieve_plugins = sieve_pipe

  sieve_pipe_socket_dir = sieve-pipe
}

service sieve-custom-action {
  executable = script-pipe /usr/lib/dovecot/sieve-pipe/sieve-custom-action.sh

  # use some unprivileged user for execution
  user = dovenull

  # socket name is program-name in Sieve (without sieve-pipe/ prefix)
  unix_listener sieve-pipe/sieve-custom-action {
  }
}

Example of direct execution

plugin {
  sieve = ~/.dovecot.sieve

  sieve_plugins = sieve_pipe

  # This directory contains the scripts that are available.
  sieve_pipe_bin_dir = /usr/lib/dovecot/sieve-pipe
}

Usage

Sieve scripts can use the new vnd.dovecot.pipe extension as follows:

require ["vnd.dovecot.pipe"];

pipe "external-program";

Read the full specification for more information.

Examples

Example of a jabber notification notify.sieve:

require [ "vnd.dovecot.pipe", "copy", "variables" ];
if header :matches "subject" "*" { set "subject" "${1}"; }
if header :matches "from" "*" { set "from" "${1}"; }
pipe :args [ "USER@DOMAIN.TLD", "${from}", "${subject}" ] :copy :try "jabber_notify.sh" ;

The jabber_notify.sh:

USER="$1"
FROM="$2"
SUBJECT="$3"
# clix accepts this as a config search directory
# you can use clix - lua based
# http://code.matthewwild.co.uk/clix/summary
# or use any other jabber cmd line client that can send things
export XDG_CONFIG_HOME=/srv/mail
/srv/mail/clix.bin send -q --account=default --to="$USER" "New mail from ${FROM} about ${SUBJECT}" 
# we don't care about the exit status in this case
exit 0

The $XDG_CONFIG_HOME/.clixrc:

[default]
jid=USER@DOMAIN.TLD
password=PASSWORD