File: //usr/share/doc/pam/txts/README.pam_exec
pam_exec — PAM module which calls an external command
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DESCRIPTION
pam_exec is a PAM module that can be used to run an external command.
The child's environment is set to the current PAM environment list, as returned
by pam_getenvlist(3) In addition, the following PAM items are exported as
environment variables: PAM_RHOST, PAM_RUSER, PAM_SERVICE, PAM_TTY, PAM_USER and
PAM_TYPE, which contains one of the module types: account, auth, password,
open_session and close_session.
Commands called by pam_exec need to be aware of that the user can have controll
over the environment.
OPTIONS
debug
    Print debug information.
expose_authtok
    During authentication the calling command can read the password from stdin
    (3). Only first PAM_MAX_RESP_SIZE bytes of a password are provided to the
    command.
log=file
    The output of the command is appended to file
type=type
    Only run the command if the module type matches the given type.
stdout
    Per default the output of the executed command is written to /dev/null.
    With this option, the stdout output of the executed command is redirected
    to the calling application. It's in the responsibility of this application
    what happens with the output. The log option is ignored.
quiet
    Per default pam_exec.so will echo the exit status of the external command
    if it fails. Specifying this option will suppress the message.
seteuid
    Per default pam_exec.so will execute the external command with the real
    user ID of the calling process. Specifying this option means the command is
    run with the effective user ID.
EXAMPLES
Add the following line to /etc/pam.d/passwd to rebuild the NIS database after
each local password change:
        password optional pam_exec.so seteuid /usr/bin/make -C /var/yp
This will execute the command
make -C /var/yp
with effective user ID.
AUTHOR
pam_exec was written by Thorsten Kukuk <kukuk@thkukuk.de> and Josh Triplett
<josh@joshtriplett.org>.