PIPE(8) PIPE(8)
NAME
pipe - Postfix delivery to external command
SYNOPSIS
pipe [generic Postfix daemon options] command_attributes...
DESCRIPTION
The pipe daemon processes requests from the Postfix queue
manager to deliver messages to external commands. Each
delivery request specifies a queue file, a sender address,
a domain or host to deliver to, and one or more recipi-
ents. This program expects to be run from the master(8)
process manager.
The pipe daemon updates queue files and marks recipients
as finished, or it informs the queue manager that delivery
should be tried again at a later time. Delivery problem
reports are sent to the bounce(8) or defer(8) daemon as
appropriate.
COMMAND ATTRIBUTE SYNTAX
The external command attributes are given in the master.cf
file at the end of a service definition. The syntax is as
follows:
flags=FR> (optional)
Optional message processing flags. By default, a
message is copied unchanged.
F Prepend a "From sender time_stamp" envelope
header to the message content. This is
expected by, for example, UUCP software. The
F flag also causes an empty line to be
appended to the message.
R Prepend a Return-Path: message header with
the envelope sender address.
> Prepend > to lines starting with "From ".
This is expected by, for example, UUCP soft-
ware.
user=username (required)
user=username:groupname
The external command is executed with the rights of
the specified username. The software refuses to
execute commands with root privileges, or with the
privileges of the mail system owner. If groupname
is specified, the corresponding group ID is used
instead of the group ID of of username.
argv=command... (required)
The command to be executed. This must be specified
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PIPE(8) PIPE(8)
as the last command attribute. The command is exe-
cuted directly, i.e. without interpretation of
shell meta characters by a shell command inter-
preter.
In the command argument vector, the following
macros are recognized and replaced with correspond-
ing information from the Postfix queue manager
delivery request:
${extension}
This macro expands to the extension part of
a recipient address. For example, with an
address user+foo@domain the extension is
foo. A command-line argument that contains
${extension} expands into as many command-
line arguments as there are recipients.
${mailbox}
This macro expands to the complete local
part of a recipient address. For example,
with an address user+foo@domain the mailbox
is user+foo. A command-line argument that
contains ${mailbox} expands into as many
command-line arguments as there are recipi-
ents.
${nexthop}
This macro expands to the next-hop hostname.
${recipient}
This macro expands to the complete recipient
address. A command-line argument that con-
tains ${recipient} expands into as many com-
mand-line arguments as there are recipients.
${sender}
This macro expands to the envelope sender
address.
${user}
This macro expands to the username part of a
recipient address. For example, with an
address user+foo@domain the username part is
user. A command-line argument that contains
${user} expands into as many command-line
arguments as there are recipients.
In addition to the form ${name}, the forms $name and
$(name) are also recognized. Specify $$ where a single $
is wanted.
DIAGNOSTICS
Command exit status codes are expected to follow the
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PIPE(8) PIPE(8)
conventions defined in <sysexits.h>.
Problems and transactions are logged to syslogd(8). Cor-
rupted message files are marked so that the queue manager
can move them to the corrupt queue for further inspection.
SECURITY
This program needs a dual personality 1) to access the
private Postfix queue and IPC mechanisms, and 2) to exe-
cute external commands as the specified user. It is there-
fore security sensitive.
CONFIGURATION PARAMETERS
The following main.cf parameters are especially relevant
to this program. See the Postfix main.cf file for syntax
details and for default values. Use the postfix reload
command after a configuration change.
Miscellaneous
mail_owner
The process privileges used while not running an
external command.
Resource controls
In the text below, transport is the first field in a mas-
ter.cf entry.
transport_destination_concurrency_limit
Limit the number of parallel deliveries to the same
destination, for delivery via the named transport.
The default limit is taken from the default_desti-
nation_concurrency_limit parameter. The limit is
enforced by the Postfix queue manager.
transport_destination_recipient_limit
Limit the number of recipients per message deliv-
ery, for delivery via the named transport. The
default limit is taken from the default_destina-
tion_recipient_limit parameter. The limit is
enforced by the Postfix queue manager.
transport_time_limit
Limit the time for delivery to external command,
for delivery via the named transport. The default
limit is taken from the command_time_limit parame-
ter. The limit is enforced by the Postfix queue
manager.
SEE ALSO
bounce(8) non-delivery status reports
master(8) process manager
qmgr(8) queue manager
syslogd(8) system logging
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PIPE(8) PIPE(8)
LICENSE
The Secure Mailer license must be distributed with this
software.
AUTHOR(S)
Wietse Venema
IBM T.J. Watson Research
P.O. Box 704
Yorktown Heights, NY 10598, USA
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