Ubuntu Manpage: wdm - WINGs Display Manager

NAME

       wdm - WINGs Display Manager

SYNOPSIS

       wdm [ options ]

DESCRIPTION

       wdm  is  an  X  display  manager based on the original X11 X Display Manager (xdm).  It features numerous
       functionality improvements, including the ability to reboot or halt the machine (once the proper password
       has been supplied) and to select from a list of available X sessions to start.  The  look  of  the  login
       panel is somewhat configurable, too.

OPTIONS

Except for -config, all of these options can be specified as resources.

-config configuration_file
Names the configuration file, which specifies resources to control the behavior of wdm.
#configdir#/wdm-config is the default.

-nodaemon
Specifies ``false'' as the value for the DisplayManager.daemonMode resource. This suppresses the
normal daemon behavior, which is for wdm to close all file descriptors, disassociate itself from
the controlling terminal, and put itself in the background when it first starts up.

-debug debug_level
Specifies the numeric value for the DisplayManager.debugLevel resource. A non-zero value causes
wdm to print lots of debugging statements to the terminal; it also disables the
DisplayManager.daemonMode resource, forcing wdm to run synchronously. To interpret these
debugging messages, a copy of the source code for wdm is almost a necessity. No attempt has been
made to rationalize or standardize the output.

-error error_log_file
Specifies the value for the DisplayManager.errorLogFile resource. This file contains errors from
wdm as well as anything written to stderr by the various scripts and programs run during the
progress of the session.

-syslog facility
Specifies the value for the DisplayManager.syslogFacility resource. This is factility to use with
all messages if log is redirected to syslog.

-usesyslog
Specifies ``true'' as the value for the DisplayManager.useSyslog resource. This will force all
messages go to syslog with facility specified by DisplayManager.syslogFacility resource.

-useerrfile
Specifies ``false'' as the value for the DisplayManager.useSyslog resource. This will force all
messages go to log file specified by DisplayManager.errorLogFile resource.

-resources resource_file
Specifies the value for the DisplayManager*resources resource. This file is loaded using xrdb to
specify configuration parameters for the authentication widget.

-server server_entry
Specifies the value for the DisplayManager.servers resource.

-udpPort port_number
Specifies the value for the DisplayManager.requestPort resource. This sets the port-number which
wdm will monitor for XDMCP requests. As XDMCP uses the registered well-known UDP port 177, this
resource should not be changed except for debugging. If set to 0 wdm will not listen for XDMCP or
Chooser requests.

-session session_program
Specifies the value for the DisplayManager*session resource. This indicates the program to run as
the session after the user has logged in.

-xrm resource_specification
Allows an arbitrary resource to be specified, as in most X Toolkit applications.

RESOURCES

At many stages the actions of wdm can be controlled through the use of its configuration file, which is
in the X resource format. Some resources modify the behavior of wdm on all displays, while others modify
its behavior on a single display. Where actions relate to a specific display, the display name is
inserted into the resource name between ``DisplayManager'' and the final resource name segment.

For local displays, the resource name and class are as read from the Xservers file.

For remote displays, the resource name is what the network address of the display resolves to. See the
removeDomain resource. The name must match exactly; wdm is not aware of all the network aliases that
might reach a given display. If the name resolve fails, the address is used. The resource class is as
sent by the display in the XDMCP Manage request.

Because the resource manager uses colons to separate the name of the resource from its value and dots to
separate resource name parts, wdm substitutes underscores for both dots and colons when generating the
resource name. For example, DisplayManager.expo_x_org_0.startup is the name of the resource which
defines the startup shell file for the ``expo.x.org:0'' display.

DisplayManager.servers
This resource either specifies a file name full of server entries, one per line (if the value
starts with a slash), or a single server entry. See the section Local Server Specification for
the details.

DisplayManager.requestPort
This indicates the UDP port number which wdm uses to listen for incoming XDMCP requests. Unless
you need to debug the system, leave this with its default value of 177.

DisplayManager.errorLogFile
Error output is normally directed at the system console. To redirect it, set this resource to a
file name. A method to send these messages to syslog should be developed for systems which
support it; however, the wide variety of interfaces precludes any system-independent
implementation. This file also contains any output directed to stderr by the Xsetup, Xstartup,
Xsession and Xreset files, so it will contain descriptions of problems in those scripts as well.

DisplayManager.debugLevel
If the integer value of this resource is greater than zero, reams of debugging information will be
printed. It also disables daemon mode, which would redirect the information into the bit-bucket,
and allows non-root users to run wdm, which would normally not be useful.

DisplayManager.daemonMode
Normally, wdm attempts to make itself into a daemon process unassociated with any terminal. This
is accomplished by forking and leaving the parent process to exit, then closing file descriptors
and releasing the controlling terminal. In some environments this is not desired (in particular,
when debugging). Setting this resource to ``false'' will disable this feature.

DisplayManager.pidFile
The filename specified will be created to contain an ASCII representation of the process-id of the
main wdm process. Xdm also uses file locking on this file to attempt to eliminate multiple
daemons running on the same machine, which would cause quite a bit of havoc.

DisplayManager.lockPidFile
This is the resource which controls whether wdm uses file locking to keep multiple display
managers from running amok. On System V, this uses the lockf library call, while on BSD it uses
flock.

DisplayManager.authDir
This names a directory under which wdm stores authorization files while initializing the session.
The default value is #configdir#. Can be overridden for specific displays by
DisplayManager.DISPLAY.authFile.

DisplayManager.autoRescan
This boolean controls whether wdm rescans the configuration, servers, access control and
authentication keys files after a session terminates and the files have changed. By default it is
``true.'' You can force wdm to reread these files by sending a SIGHUP to the main process.

DisplayManager.removeDomainname
When computing the display name for XDMCP clients, the name resolver will typically create a fully
qualified host name for the terminal. As this is sometimes confusing, wdm will remove the domain
name portion of the host name if it is the same as the domain name of the local host when this
variable is set. By default the value is ``true.''

DisplayManager.keyFile
XDM-AUTHENTICATION-1 style XDMCP authentication requires that a private key be shared between wdm
and the terminal. This resource specifies the file containing those values. Each entry in the
file consists of a display name and the shared key. By default, wdm does not include support for
XDM-AUTHENTICATION-1, as it requires DES which is not generally distributable because of United
States export restrictions.

DisplayManager.accessFile
To prevent unauthorized XDMCP service and to allow forwarding of XDMCP IndirectQuery requests,
this file contains a database of hostnames which are either allowed direct access to this machine,
or have a list of hosts to which queries should be forwarded to. The format of this file is
described in the section XDMCP Access Control.

DisplayManager.exportList
A list of additional environment variables, separated by white space, to pass on to the Xsetup,
Xstartup, Xsession, and Xreset programs.

DisplayManager.randomFile
A file to checksum to generate the seed of authorization keys. This should be a file that changes
frequently. The default is /dev/urandom.

DisplayManager.greeterLib
On systems that support a dynamically-loadable greeter library, the name of the library. The
default is /usr/lib/X11/xdm/libXdmGreet.so. This not used in Debian.

DisplayManager.choiceTimeout
Number of seconds to wait for display to respond after user has selected a host from the chooser.
If the display sends an XDMCP IndirectQuery within this time, the request is forwarded to the
chosen host. Otherwise, it is assumed to be from a new session and the chooser is offered again.
Default is 15.

DisplayManager.sourceAddress
Use the numeric IP address of the incoming connection on multihomed hosts instead of the host
name. This is to avoid trying to connect on the wrong interface which might be down at this time.

DisplayManager.willing
This specifies a program which is run (as) root when an an XDMCP BroadcastQuery is received and
this host is configured to offer XDMCP display management. The output of this program may be
displayed on a chooser window. If no program is specified, the string Willing to manage is sent.

DisplayManager.DISPLAY.resources
This resource specifies the name of the file to be loaded by xrdb as the resource database onto
the root window of screen 0 of the display. The Xsetup program, the Login widget, and chooser
will use the resources set in this file. This resource data base is loaded just before the
authentication procedure is started, so it can control the appearance of the login window. See
the section Authentication Widget, which describes the various resources that are appropriate to
place in this file. There is no default value for this resource, but #configdir#/Xresources is
the conventional name.

DisplayManager.DISPLAY.chooser
Specifies the program run to offer a host menu for Indirect queries redirected to the special host
name CHOOSER. /usr/lib/X11/xdm/chooser is the default. See the sections XDMCP Access Control and
Chooser.

DisplayManager.DISPLAY.xrdb
Specifies the program used to load the resources. By default, wdm uses /usr/bin/xrdb.

DisplayManager.DISPLAY.cpp
This specifies the name of the C preprocessor which is used by xrdb.

DisplayManager.DISPLAY.setup
This specifies a program which is run (as root) before offering the Login window. This may be
used to change the appearance of the screen around the Login window or to put up other windows
(e.g., you may want to run xconsole here). By default, no program is run. The conventional name
for a file used here is Xsetup. See the section Setup Program.

DisplayManager.DISPLAY.startup
This specifies a program which is run (as root) after the authentication process succeeds. By
default, no program is run. The conventional name for a file used here is Xstartup. See the
section Startup Program.

DisplayManager.DISPLAY.session
This specifies the session to be executed (not running as root). By default, /usr/bin/x-terminal-
emulator is run. The conventional name is Xsession. See the section Session Program.

DisplayManager.DISPLAY.reset
This specifies a program which is run (as root) after the session terminates. By default, no
program is run. The conventional name is Xreset. See the section Reset Program.

DisplayManager.DISPLAY.openDelay

DisplayManager.DISPLAY.openRepeat

DisplayManager.DISPLAY.openTimeout

DisplayManager.DISPLAY.startAttempts
These numeric resources control the behavior of wdm when attempting to open intransigent servers.
openDelay is the length of the pause (in seconds) between successive attempts, openRepeat is the
number of attempts to make, openTimeout is the amount of time to wait while actually attempting
the open (i.e., the maximum time spent in the connect(2) system call) and startAttempts is the
number of times this entire process is done before giving up on the server. After openRepeat
attempts have been made, or if openTimeout seconds elapse in any particular attempt, wdm
terminates and restarts the server, attempting to connect again. This process is repeated
startAttempts times, at which point the display is declared dead and disabled. Although this
behavior may seem arbitrary, it has been empirically developed and works quite well on most
systems. The default values are 5 for openDelay, 5 for openRepeat, 30 for openTimeout and 4 for
startAttempts.

DisplayManager.DISPLAY.pingInterval

DisplayManager.DISPLAY.pingTimeout
To discover when remote displays disappear, wdm occasionally pings them, using an X connection and
XSync calls. pingInterval specifies the time (in minutes) between each ping attempt, pingTimeout
specifies the maximum amount of time (in minutes) to wait for the terminal to respond to the
request. If the terminal does not respond, the session is declared dead and terminated. By
default, both are set to 5 minutes. If you frequently use X terminals which can become isolated
from the managing host, you may wish to increase this value. The only worry is that sessions will
continue to exist after the terminal has been accidentally disabled. wdm will not ping local
displays. Although it would seem harmless, it is unpleasant when the workstation session is
terminated as a result of the server hanging for NFS service and not responding to the ping.

DisplayManager.DISPLAY.terminateServer
This boolean resource specifies whether the X server should be terminated when a session
terminates (instead of resetting it). This option can be used when the server tends to grow
without bound over time, in order to limit the amount of time the server is run. The default
value is ``false.''

DisplayManager.DISPLAY.userPath
Xdm sets the PATH environment variable for the session to this value. It should be a colon
separated list of directories; see sh(1) for a full description. ``:/bin:/usr/bin:/usr/games'' is
a common setting. The default value can be specified at build time in the X system configuration
file with DefaultUserPath.

DisplayManager.DISPLAY.systemPath
Xdm sets the PATH environment variable for the startup and reset scripts to the value of this
resource. The default for this resource is specified at build time by the DefaultSystemPath entry
in the system configuration file; ``/etc:/bin:/usr/bin'' is a common choice. Note the absence of
``.'' from this entry. This is a good practice to follow for root; it avoids many common Trojan
Horse system penetration schemes.

DisplayManager.DISPLAY.systemShell
Xdm sets the SHELL environment variable for the startup and reset scripts to the value of this
resource. It is /bin/sh by default.

DisplayManager.DISPLAY.failsafeClient
If the default session fails to execute, wdm will fall back to this program. This program is
executed with no arguments, but executes using the same environment variables as the session would
have had (see the section Session Program). By default, /usr/bin/x-terminal-emulator is used.

DisplayManager.DISPLAY.grabServer

DisplayManager.DISPLAY.grabTimeout
To improve security, wdm grabs the server and keyboard while reading the login name and password.
The grabServer resource specifies if the server should be held for the duration of the
name/password reading. When ``false,'' the server is ungrabbed after the keyboard grab succeeds,
otherwise the server is grabbed until just before the session begins. The default is ``false.''
The grabTimeout resource specifies the maximum time wdm will wait for the grab to succeed. The
grab may fail if some other client has the server grabbed, or possibly if the network latencies
are very high. This resource has a default value of 3 seconds; you should be cautious when
raising it, as a user can be spoofed by a look-alike window on the display. If the grab fails,
wdm kills and restarts the server (if possible) and the session.

DisplayManager.DISPLAY.authorize

DisplayManager.DISPLAY.authName
authorize is a boolean resource which controls whether wdm generates and uses authorization for
the local server connections. If authorization is used, authName is a list of authorization
mechanisms to use, separated by white space. XDMCP connections dynamically specify which
authorization mechanisms are supported, so authName is ignored in this case. When authorize is
set for a display and authorization is not available, the user is informed by having a different
message displayed in the login widget. By default, authorize is ``true.'' authName is ``MIT-
MAGIC-COOKIE-1,'' or, if XDM-AUTHORIZATION-1 is available, ``XDM-AUTHORIZATION-1 MIT-MAGIC-
COOKIE-1.''

DisplayManager.DISPLAY.authFile
This file is used to communicate the authorization data from wdm to the server, using the -auth
server command line option. It should be kept in a directory which is not world-writable as it
could easily be removed, disabling the authorization mechanism in the server. If not specified, a
name is generated from DisplayManager.authDir and the name of the display.

DisplayManager.DISPLAY.authComplain
If set to ``false,'' disables the use of the unsecureGreeting in the login window. See the
section Authentication Widget. The default is ``true.''

DisplayManager.DISPLAY.resetSignal
The number of the signal wdm sends to reset the server. See the section Controlling the Server.
The default is 1 (SIGHUP).

DisplayManager.DISPLAY.termSignal
The number of the signal wdm sends to terminate the server. See the section Controlling the
Server. The default is 15 (SIGTERM).

DisplayManager.DISPLAY.resetForAuth
The original implementation of authorization in the sample server reread the authorization file at
server reset time, instead of when checking the initial connection. As wdm generates the
authorization information just before connecting to the display, an old server would not get up-
to-date authorization information. This resource causes wdm to send SIGHUP to the server after
setting up the file, causing an additional server reset to occur, during which time the new
authorization information will be read. The default is ``false,'' which will work for all MIT
servers.

DisplayManager.DISPLAY.userAuthDir
When wdm is unable to write to the usual user authorization file ($HOME/.Xauthority), it creates a
unique file name in this directory and points the environment variable XAUTHORITY at the created
file. It uses /tmp by default.

DisplayManager.wdmLogin
Specifies the path to wdmLogin(1x)

DisplayManager.wdmWm
Is a colon separated list of window managers to use as options in the login panel. Note that if
you include the path to the window manager, it will look ugly. You may set this resource to None
if you want only NoChange to appear.

DisplayManager.wdmLogo
Path to the logo pixmap, several formats are accepted, read wdmLogin(1x) to find out more.

DisplayManager.wdmHelpFile
Path to a text file which will be displayed in the help panel, read wdmLogin(1x) to find out more.

DisplayManager.wdmDefaultUser
a default username which will be used if no username is typed.

DisplayManager.wdmDefaultPasswd
the clear text password of the default user above. BE VERY CAREFUL when using this two resources,
and don't forget to do: chmod 600 wdm-config ; chown root.root wdm-config

DisplayManager.wdmBg
Background specification. Read the BACKGROUND IMAGE SPECIFICATION section to find out about the
format. If this is not specified, then the background is not set.

DisplayManager.wdmReboot
Reboot command.

DisplayManager.wdmHalt
Halt command.

DisplayManager.wdmVerify
If true, verify user's identity for reboot/halt/exit.

DisplayManager.wdmRoot
If true, user must be root to exit.

DisplayManager.wdmAnimations
If true, enable animations consisting of shaking the panel (if an error) and rolling up the panel
(when closing it). If false, animations are disabled.

DisplayManager.wdmLocale
LANG environment variable will be set to value of this resource before starting wdmLogin.

DisplayManger.wdmCursorTheme
If you have recent version of XFree with support for transparent cursors you can select cursor
theme to use on login panel. XCURSOR_THEME environment variable will be set to value of this
resource before starting wdmLogin.

CONFIGURATION FILE

       The default location of the wdm configuration file is #configdir#/wdm-config

       Here is a reasonable configuration file, which could be named wdm-config:

            DisplayManager.servers:            /usr/lib/X11/xdm/Xservers
            DisplayManager.errorLogFile:       /usr/lib/X11/xdm/xdm-errors
            DisplayManager*resources:          /usr/lib/X11/xdm/Xresources
            DisplayManager*startup:            /usr/lib/X11/xdm/Xstartup
            DisplayManager*session:            /usr/lib/X11/xdm/Xsession
            DisplayManager.pidFile:            /usr/lib/X11/xdm/xdm-pid
            DisplayManager._0.authorize:       true
            DisplayManager*authorize:          false

       Note  that this file mostly contains references to other files.  Note also that some of the resources are
       specified with ``*'' separating the components.  These resources can be made unique  for  each  different
       display,  by  replacing  the  ``*'' with the display-name, but normally this is not very useful.  See the
       Resources section for a complete discussion.  If the entry is a host name, all comparisons are done using
       network addresses, so any name which converts to the correct network address may be used.  For  patterns,
       only canonical host names are used in the comparison, so ensure that you do not attempt to match aliases.
       Preceding  either a host name or a pattern with a `!' character causes hosts which match that entry to be
       excluded.

       To only respond to  Direct  queries  for  a  host  or  pattern,  it  can  be  followed  by  the  optional
       ``NOBROADCAST''  keyword.   This  can  be  used to prevent an wdm server from appearing on menus based on
       Broadcast queries.

       An Indirect entry also contains a host name or pattern, but follows it with  a  list  of  host  names  or
       macros to which indirect queries should be sent.

       A macro definition contains a macro name and a list of host names and other macros that the macro expands
       to.  To distinguish macros from hostnames, macro names start with a `%' character.  Macros may be nested.

       Indirect  entries  may  also specify to have wdm run chooser to offer a menu of hosts to connect to.  See
       the section Chooser.

       When checking access for a particular display host, each entry is scanned in turn and the first  matching
       entry  determines  the  response.  Direct and Broadcast entries are ignored when scanning for an Indirect
       entry and vice-versa.

       Blank lines are ignored, `#' is treated as a comment delimiter causing  the  rest  of  that  line  to  be
       ignored,  and  `\newline' causes the newline to be ignored, allowing indirect host lists to span multiple
       lines.

       Here is an example Xaccess file:

       #
       # Xaccess - XDMCP access control file
       #

       #
       # Direct/Broadcast query entries
       #

       !xtra.lcs.mit.edu   # disallow direct/broadcast service for xtra
       bambi.ogi.edu       # allow access from this particular display
       *.lcs.mit.edu       # allow access from any display in LCS

       *.deshaw.com        NOBROADCAST         # allow only direct access
       *.gw.com                                # allow direct and broadcast

       #
       # Indirect query entries
       #

       %HOSTS              expo.lcs.mit.edu xenon.lcs.mit.edu \
                           excess.lcs.mit.edu kanga.lcs.mit.edu

       extract.lcs.mit.edu xenon.lcs.mit.edu   #force extract to contact xenon
       !xtra.lcs.mit.edu   dummy               #disallow indirect access
       *.lcs.mit.edu       %HOSTS              #all others get to choose

RESOURCES FILE

       The Xresources file is loaded onto the display as a resource database using xrdb.  As the  authentication
       widget reads this database before starting up, it usually contains parameters for that widget:

            xlogin*login.translations: #override\
                 Ctrl<Key>R: abort-display()\n\
                 <Key>F1: set-session-argument(failsafe) finish-field()\n\
                 <Key>Return: set-session-argument() finish-field()
            xlogin*borderWidth: 3
            xlogin*greeting: CLIENTHOST
            #ifdef COLOR
            xlogin*greetColor: CadetBlue
            xlogin*failColor: red
            #endif

       Please  note the translations entry; it specifies a few new translations for the widget which allow users
       to escape from the default session (and avoid troubles that may occur in it).  Note that if #override  is
       not  specified,  the  default  translations  are removed and replaced by the new value, not a very useful
       result as some of the default translations are quite useful (such  as  ``<Key>:  insert-char  ()''  which
       responds to normal typing).

       This file may also contain resources for the setup program and chooser.

SETUP PROGRAM

       The  Xsetup  file  is run after the server is reset, but before the Login window is offered.  The file is
       typically a shell script.  It is run as root, so should be careful about security.  This is the place  to
       change  the  root  background  or  bring up other windows that should appear on the screen along with the
       Login widget.

       In addition to any specified  by  DisplayManager.exportList,  the  following  environment  variables  are
       passed:

            DISPLAY        the associated display name
            PATH           the value of DisplayManager.DISPLAY.systemPath
            SHELL          the value of DisplayManager.DISPLAY.systemShell
            XAUTHORITY     may be set to an authority file

       Note  that  since  wdm  grabs the keyboard, any other windows will not be able to receive keyboard input.
       They will be able to interact with the mouse, however; beware  of  potential  security  holes  here.   If
       DisplayManager.DISPLAY.grabServer  is  set,  Xsetup  will  not  be able to connect to the display at all.
       Resources for this program can be put into the file named by DisplayManager.DISPLAY.resources.

       Here is a sample Xsetup script:

            #!/bin/sh
            # Xsetup_0 - setup script for one workstation
            xcmsdb < /usr/local/lib/monitors/alex.0
            xconsole -geometry 480x130-0-0 -notify -verbose -exitOnFail &

BACKGROUND IMAGE SPECIFICATION

       There are several possible ways of specifying a background image. The generic format is type:image.  type
       can be any of:

       none   The backgound is not set.

       solid  it renders a solid background, and image is a color name

       hgradient, vgradient, dgradient
              a gradient (either horizontal, vertical or diagonal) will be rendered. image is comma separated of
              color names, and any number of colors can be specified.

       pixmap a pixmap will be used for the background. image is the full path to an image file (tiff, png, jpeg
              and xpm allowed) and it will be scaled to use the full screen.

AUTHOR

       wdm  was written by Gene Czarcinski <genec@mindspring.com>. wdm is based on work by Tom Rothamel and xdm,
       (c) 1988 X Consortium

       This man page was written by Marcelo Magallon <mmagallo@debian.org>  and  extensively  modified  by  Noah
       Meyerhans <noahm@debian.org>.  Much of the content was taken from xdm's manual page.

                                                    July 2002                                            wdm(1x)