NAME

       xdm.options - configuration options for the X display manager

DESCRIPTION

       /etc/X11/xdm/xdm.options  contains  a  set  of flags that determine some of the behavior of the X display
       manager xdm(1x).  Most of xdm's behavior is customized through other files; consult the xdm  manual  page
       if this manual page does not describe the behavior you want to alter.

       /etc/X11/xdm/xdm.options  may  contain  comments,  which begin with a hash mark (‘#’) and end at the next
       newline, just like comments in shell scripts.  The rest  of  the  file  consists  of  options  which  are
       expressed  as  words  separated by hyphens, with only one option per line.  Options are enabled by simply
       placing them in the file; they are disabled by prefixing the option name with ‘no-’.

       Available options are:

       ignore-nologin
              Normally, if the nologin(5) file exists, its contents will be  displayed  using  xmessage(1x)  (if
              xmessage  is  available),  and the user will be returned to the xdm login screen after xmessage is
              dismissed instead of starting the X session.  If this option is enabled, xdm starts a  session  as
              usual  (after  xmessage is dismissed, if xmessage is available and the nologin file exists).  This
              behavior is disabled by default: nologin is heeded, not ignored.

       restart-on-upgrade
              Enable this option with caution on ‘production’ machines; it causes the daemon to be  stopped  and
              restarted  on  upgrade,  even if the process has children (which means it is managing X sessions).
              Typically when a package that contains a daemon is being installed  or  upgraded,  its  maintainer
              scripts  stop  a running daemon process before installing the new binary, and restart it after the
              new binary is installed.  Stopping xdm causes immediate termination of any sessions it manages; in
              some situations this could be an unwelcome surprise (for instance, for remote xdm users who had no
              idea the administrator was performing system maintenance).  On the other hand, for  machines  that
              stay  up  for  long  periods  of time, leaving the old daemon running can be a bad idea if the new
              version has, for instance, a fix for a security vulnerability (overwriting xdm's executable on the
              file system has no effect on the copy of xdm in memory).  The  xdm  package's  pre-removal  script
              checks  to  see  if  the  xdm  process has any children; if it does, it is possible that someone's
              session would be killed by stopping xdm, so a warning is issued and an opportunity  to  abort  the
              upgrade  of  xdm is provided.  Furthermore, restarting xdm on upgrade can be surprising, because a
              locally-managed X server can change the active VT even while  other  packages  are  continuing  to
              upgrade.   If,  by  intent or accident, the X server does not honor the key sequence to switch VTs
              back to a virtual console, this can be undesirable.  This behavior is  disabled  by  default:  xdm
              will be not be stopped or started during an upgrade of its package; the administrator will have to
              do so by hand (with invoke-rc.d xdm restart or by rebooting the system) before the newly installed
              xdm binary is used.

       start-on-install
              Enable  this  option  with  caution;  it causes the xdm daemon to be started immediately after the
              package is installed.   See  the  above  entry  regarding  restart-on-upgrade  for  other  caveats
              regarding the consequences of starting the xdm daemon during package management.  This behavior is
              disabled  by  default:  xdm  will  not be started when it is installed.  Changing this setting can
              affect future installs if the package is removed,  but  not  purged  (which  removes  ‘conffiles’,
              including xdm.options).

       use-sessreg
              This  option  causes  the /etc/X11/xdm/Xreset script to call the sessreg(1x) program to register X
              sessions managed by xdm in the utmp(5) and wtmp(5) files.  If it is disabled, the  utmp  and  wtmp
              files  will  have no record of xdm sessions.  This behavior is enabled by default; sessreg will be
              used.

       Users of older versions of the Debian system should note that the ‘run-xconsole’ option has been removed.
       The shell script named /etc/X11/xdm/Xreset can be edited to disable or modify the running of xconsole  on
       the xdm greeter screen; see xdm(1x) for more information.

AUTHORS

       Stephen  Early,  Mark Eichin, and Branden Robinson customized xdm's startup and reset scripts and package
       maintainer scripts to implement the functionality described above.   This  manual  page  was  written  by
       Branden Robinson.

SEE ALSO

       sessreg(1x), xmessage(1x), xdm(1x), nologin(5), utmp(5), wtmp(5)

Debian Project                                     2004-10-31                                     xdm.options(5)