NAME

       postlock - lock mail folder and execute command

SYNOPSIS

       postlock [-c config_dir] [-l lock_style]
               [-v] file command...

DESCRIPTION

       The postlock(1) command locks file for exclusive access, and executes command. The locking
       method is compatible with the Postfix UNIX-style local delivery agent.

       Options:

       -c config_dir
              Read the main.cf configuration file in the named directory instead of  the  default
              configuration directory.

       -l lock_style
              Override  the  locking method specified via the mailbox_delivery_lock configuration
              parameter (see below).

       -v     Enable verbose logging  for  debugging  purposes.  Multiple  -v  options  make  the
              software increasingly verbose.

       Arguments:

       file   A mailbox file. The user should have read/write permission.

       command...
              The  command  to execute while file is locked for exclusive access.  The command is
              executed directly, i.e. without interpretation by a shell command interpreter.

DIAGNOSTICS

       The result status is 75 (EX_TEMPFAIL) when postlock(1) could  not  perform  the  requested
       operation.  Otherwise, the exit status is the exit status from the command.

BUGS

       With  remote  file  systems,  the ability to acquire a lock does not necessarily eliminate
       access conflicts. Avoid file access by processes running on different machines.

ENVIRONMENT

       MAIL_CONFIG
              Directory with Postfix configuration files.

       MAIL_VERBOSE
              Enable verbose logging for debugging purposes.

CONFIGURATION PARAMETERS

       The following main.cf parameters are especially relevant to this program.  The text  below
       provides only a parameter summary. See postconf(5) for more details including examples.

LOCKING CONTROLS

       deliver_lock_attempts (20)
              The  maximal  number  of attempts to acquire an exclusive lock on a mailbox file or
              bounce(8) logfile.

       deliver_lock_delay (1s)
              The time between attempts to acquire  an  exclusive  lock  on  a  mailbox  file  or
              bounce(8) logfile.

       stale_lock_time (500s)
              The time after which a stale exclusive mailbox lockfile is removed.

       mailbox_delivery_lock (see 'postconf -d' output)
              How to lock a UNIX-style local(8) mailbox before attempting delivery.

RESOURCE AND RATE CONTROLS

       fork_attempts (5)
              The maximal number of attempts to fork() a child process.

       fork_delay (1s)
              The delay between attempts to fork() a child process.

MISCELLANEOUS CONTROLS

       config_directory (see 'postconf -d' output)
              The default location of the Postfix main.cf and master.cf configuration files.

       import_environment (see 'postconf -d' output)
              The  list  of  environment parameters that a privileged Postfix process will import
              from a non-Postfix parent process, or name=value environment overrides.

SEE ALSO

       postconf(5), configuration parameters

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

       Wietse Venema
       Google, Inc.
       111 8th Avenue
       New York, NY 10011, USA

                                                                                      POSTLOCK(1)