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| -rw-r--r-- | man/man8/spawn.8 | 156 |
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diff --git a/man/man8/spawn.8 b/man/man8/spawn.8 new file mode 100644 index 0000000..8baa440 --- /dev/null +++ b/man/man8/spawn.8 @@ -0,0 +1,156 @@ +.TH SPAWN 8 +.ad +.fi +.SH NAME +spawn +\- +Postfix external command spawner +.SH "SYNOPSIS" +.na +.nf +\fBspawn\fR [generic Postfix daemon options] command_attributes... +.SH DESCRIPTION +.ad +.fi +The \fBspawn\fR(8) daemon provides the Postfix equivalent +of \fBinetd\fR. +It listens on a port as specified in the Postfix \fBmaster.cf\fR file +and spawns an external command whenever a connection is established. +The connection can be made over local IPC (such as UNIX\-domain +sockets) or over non\-local IPC (such as TCP sockets). +The command's standard input, output and error streams are connected +directly to the communication endpoint. + +This daemon expects to be run from the \fBmaster\fR(8) process +manager. +.SH "COMMAND ATTRIBUTE SYNTAX" +.na +.nf +.ad +.fi +The external command attributes are given in the \fBmaster.cf\fR +file at the end of a service definition. The syntax is as follows: +.IP "\fBuser\fR=\fIusername\fR (required)" +.IP "\fBuser\fR=\fIusername\fR:\fIgroupname\fR" +The external command is executed with the rights of the +specified \fIusername\fR. The software refuses to execute +commands with root privileges, or with the privileges of the +mail system owner. If \fIgroupname\fR is specified, the +corresponding group ID is used instead of the group ID +of \fIusername\fR. +.IP "\fBargv\fR=\fIcommand\fR... (required)" +The command to be executed. This must be specified as the +last command attribute. +The command is executed directly, i.e. without interpretation of +shell meta characters by a shell command interpreter. +.SH BUGS +.ad +.fi +In order to enforce standard Postfix process resource controls, +the \fBspawn\fR(8) daemon runs only one external command at a time. +As such, it presents a noticeable overhead by wasting precious +process resources. The \fBspawn\fR(8) daemon is expected to be +replaced by a more structural solution. +.SH DIAGNOSTICS +.ad +.fi +The \fBspawn\fR(8) daemon reports abnormal child exits. +Problems are logged to \fBsyslogd\fR(8) or \fBpostlogd\fR(8). +.SH "SECURITY" +.na +.nf +.fi +.ad +This program needs root privilege in order to execute external +commands as the specified user. It is therefore security sensitive. +However the \fBspawn\fR(8) daemon does not talk to the external command +and thus is not vulnerable to data\-driven attacks. +.SH "CONFIGURATION PARAMETERS" +.na +.nf +.ad +.fi +Changes to \fBmain.cf\fR are picked up automatically as \fBspawn\fR(8) +processes run for only a limited amount of time. Use the command +"\fBpostfix reload\fR" to speed up a change. + +The text below provides only a parameter summary. See +\fBpostconf\fR(5) for more details including examples. + +In the text below, \fItransport\fR is the first field of the entry +in the \fBmaster.cf\fR file. +.SH "RESOURCE AND RATE CONTROL" +.na +.nf +.ad +.fi +.IP "\fBtransport_time_limit ($command_time_limit)\fR" +A transport\-specific override for the command_time_limit parameter +value, where \fItransport\fR is the master.cf name of the message +delivery transport. +.SH "MISCELLANEOUS" +.na +.nf +.ad +.fi +.IP "\fBconfig_directory (see 'postconf -d' output)\fR" +The default location of the Postfix main.cf and master.cf +configuration files. +.IP "\fBdaemon_timeout (18000s)\fR" +How much time a Postfix daemon process may take to handle a +request before it is terminated by a built\-in watchdog timer. +.IP "\fBexport_environment (see 'postconf -d' output)\fR" +The list of environment variables that a Postfix process will export +to non\-Postfix processes. +.IP "\fBipc_timeout (3600s)\fR" +The time limit for sending or receiving information over an internal +communication channel. +.IP "\fBmail_owner (postfix)\fR" +The UNIX system account that owns the Postfix queue and most Postfix +daemon processes. +.IP "\fBmax_idle (100s)\fR" +The maximum amount of time that an idle Postfix daemon process waits +for an incoming connection before terminating voluntarily. +.IP "\fBmax_use (100)\fR" +The maximal number of incoming connections that a Postfix daemon +process will service before terminating voluntarily. +.IP "\fBprocess_id (read\-only)\fR" +The process ID of a Postfix command or daemon process. +.IP "\fBprocess_name (read\-only)\fR" +The process name of a Postfix command or daemon process. +.IP "\fBqueue_directory (see 'postconf -d' output)\fR" +The location of the Postfix top\-level queue directory. +.IP "\fBsyslog_facility (mail)\fR" +The syslog facility of Postfix logging. +.IP "\fBsyslog_name (see 'postconf -d' output)\fR" +A prefix that is prepended to the process name in syslog +records, so that, for example, "smtpd" becomes "prefix/smtpd". +.PP +Available in Postfix 3.3 and later: +.IP "\fBservice_name (read\-only)\fR" +The master.cf service name of a Postfix daemon process. +.SH "SEE ALSO" +.na +.nf +postconf(5), configuration parameters +master(8), process manager +postlogd(8), Postfix logging +syslogd(8), system logging +.SH "LICENSE" +.na +.nf +.ad +.fi +The Secure Mailer license must be distributed with this software. +.SH "AUTHOR(S)" +.na +.nf +Wietse Venema +IBM T.J. Watson Research +P.O. Box 704 +Yorktown Heights, NY 10598, USA + +Wietse Venema +Google, Inc. +111 8th Avenue +New York, NY 10011, USA |