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/mem.
- 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/X11R6/bin/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/X11R6/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/X11R6/bin/xterm 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/X11R6/bin:/usr/ucb'' 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:/usr/X11R6/bin:/usr/ucb'' 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/X11R6/bin/xterm 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/X11R6/lib/X11/xdm/Xservers
DisplayManager.errorLogFile: /usr/X11R6/lib/X11/xdm/xdm-errors
DisplayManager*resources: /usr/X11R6/lib/X11/xdm/Xresources
DisplayManager*startup: /usr/X11R6/lib/X11/xdm/Xstartup
DisplayManager*session: /usr/X11R6/lib/X11/xdm/Xsession
DisplayManager.pidFile: /usr/X11R6/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/X11R6/lib/monitors/alex.0
xconsole -geometry 480x130-0-0 -notify -verbose -exitOnFail &
BACKGROUND IMAGE SPECIFICATION¶
There are several possible ways of specifing 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 backgroud, 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.
SEE ALSO¶
wdmLogin(1x)
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.