POSTLOCK 1

### 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.

### 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