The Files &tdm; Uses for ConfigurationThis chapter documents the files that control &tdm;'s behavior.
Some of this can be also controlled from the &kcontrol; module, but
not all.&tdmrc; - The &tdm; master configuration fileThe basic format of the file is INI-like.
Options are key/value pairs, placed in sections.
Everything in the file is case sensitive.
Syntactic errors and unrecognized key/section identifiers cause &tdm; to
issue non-fatal error messages.Lines beginning with # are comments; empty lines
are ignored as well.Sections are denoted by
[Name of Section].
You can configure every X-display individually.Every display has a display name, which consists of a host name
(which is empty for local displays specified in
or ), a colon, and a display number.
Additionally, a display belongs to a
display class (which can be ignored in most cases).Sections with display-specific settings have the formal syntax
[X-host [ :number [ _class ] ] -sub-section]All sections with the same sub-section
make up a section class.You can use the wildcard * (match any) for
host, number,
and class. You may omit trailing components;
they are assumed to be * then. The host part may be a
domain specification like .inf.tu-dresden.de
or the wildcard + (match non-empty).From which section a setting is actually taken is determined by
these rules:An exact match takes precedence over a partial match (for the
host part), which in turn takes precedence over a wildcard
(+ taking precendence over *).Precedence decreases from left to right for equally exact matches.
Example: display name myhost.foo:0, class dpy[X-myhost.foo:0_dpy] precedes[X-myhost.foo:0_*] (same as [X-myhost.foo:0]) precedes[X-myhost.foo:*_dpy] precedes[X-myhost.foo:*_*] (same as [X-myhost.foo]) precedes[X-.foo:*_*] (same as [X-.foo]) precedes[X-+:0_dpy] precedes[X-*:0_dpy] precedes[X-*:0_*] (same as [X-*:0]) precedes[X-*:*_*] (same as [X-*]).These sections do not match this display:[X-hishost], [X-myhost.foo:0_dec], [X-*:1], [X-:*]Common sections are [X-*] (all displays), [X-:*] (all local displays)
and [X-:0] (the first local display).The format for all keys is
=value.
Keys are only valid in the section class they are defined for.
Some keys do not apply to particular displays, in which case they are ignored.
If a setting is not found in any matching section, the default
is used.Special characters need to be backslash-escaped (leading and trailing
spaces (\s), tab (\t), linefeed
(\n), carriage return (\r) and the
backslash itself (\\)).In lists, fields are separated with commas without whitespace in between.
Some command strings are subject to simplified sh-style word splitting:
single quotes (') and double quotes (")
have the usual meaning; the backslash quotes everything (not only special
characters). Note that the backslashes need to be doubled because of the
two levels of quoting.A pristine &tdmrc; is very thoroughly commented.
All comments will be lost if you change this file with the
kcontrol frontend.The [General] section of &tdmrc;
This section contains global options that do not fit into any specific section.
This option exists solely for the purpose of clean automatic upgrades.
Do not change it, you may interfere with future
upgrades and this could result in &tdm; failing to run.
List of displays (&X-Server;s) permanently managed by &tdm;. Displays with a
hostname are foreign displays which are expected to be already running,
the others are local displays for which &tdm; starts an own &X-Server;;
see . Each display may belong to a display class;
append it to the display name separated by an underscore.
See for the details.
The default is :0.
List of on-demand displays. See for syntax.
Empty by default.
List of Virtual Terminals to allocate to &X-Server;s. For negative numbers the
absolute value is used, and the VT will be allocated only
if the kernel says it is free. If &tdm; exhausts this list, it will allocate
free VTs greater than the absolute value of the last entry
in this list.
Currently Linux only.
Empty by default.
This option is for operating systems (OSs) with support
for virtual terminals (VTs), by both &tdm; and the
OSs itself.
Currently this applies only to Linux.
When &tdm; switches to console mode, it starts monitoring all
TTY lines listed here (without the leading
/dev/).
If none of them is active for some time, &tdm; switches back to the X login.
Empty by default.
The filename specified will be created to contain an ASCII representation
of the process ID of the main &tdm; process; the PID will not be stored
if the filename is empty.
Empty by default.
This option controls whether &tdm; uses file locking to keep multiple
display managers from running onto each other.
The default is true.
This names a directory under which &tdm; stores &X-Server; authorization
files while initializing the session. &tdm; expects the system to clean up
this directory from stale files on reboot.
The authorization file to be used for a particular display can be
specified with the option in [X-*-Core].
The default is /var/run/xauth.
This boolean controls whether &tdm; automatically re-reads its
configuration files if it finds them to have changed.
The default is true.
Additional environment variables &tdm; should pass on to all programs it runs.
LD_LIBRARY_PATH and XCURSOR_THEME are good candidates;
otherwise, it should not be necessary very often.
Empty by default.
If the system has no native entropy source like /dev/urandom (see
) and no entropy daemon like EGD (see
and ) is running,
&tdm; will fall back to its own pseudo-random number generator
that will, among other things, successively checksum parts of this file
(which, obviously, should change frequently).
This option does not exist on Linux and various BSDs.
The default is /dev/mem.
If the system has no native entropy source like /dev/urandom (see
), read random data from a Pseudo-Random
Number Generator Daemon,
like EGD (http://egd.sourceforge.net) via this UNIX domain socket.
This option does not exist on Linux and various BSDs.
Empty by default.
Same as , only use a TCP socket on localhost.
The path to a character device which &tdm; should read random data from.
Empty means to use the system's preferred entropy device if there is one.
This option does not exist on OpenBSD, as it uses the arc4_random
function instead.
Empty by default.
The directory in which the command FiFos should
be created; make it empty to disable them.
The default is /var/run/xdmctl.
The group to which the global command FiFo should belong;
can be either a name or a numerical ID.
The directory in which &tdm; should store persistent working data; such data
is, for example, the previous user that logged in on a particular display.
The default is /var/lib/tdm.
The directory in which &tdm; should store users' .dmrc files. This is only
needed if the home directories are not readable before actually logging in
(like with AFS).
Empty by default.The [Xdmcp] section of &tdmrc;
This section contains options that control &tdm;'s handling of
&XDMCP; requests.
Whether &tdm; should listen to incoming &XDMCP; requests.
The default is true.
This indicates the UDP port number which &tdm; uses to listen for incoming
&XDMCP; requests. Unless you need to debug the system, leave this with its
default value.
The default is 177.
XDM-AUTHENTICATION-1 style &XDMCP; authentication requires a private
key to be shared between &tdm; and the terminal. This option specifies
the file containing those values. Each entry in the file consists of a
display name and the shared key.
Empty by default.
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 default is ${kde_confdir}/tdm/Xaccess.
Number of seconds to wait for the display to respond after the 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.
The default is 15.
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, &tdm; 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 option
is enabled.
The default is true.
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.
The default is false.
This specifies a program which is run (as
root) when an &XDMCP;
DirectQuery or BroadcastQuery is received and this host is configured
to offer &XDMCP; display management. The output of this program may be
displayed in a chooser window. If no program is specified, the string
Willing to manage is sent.
Empty by default.The [Shutdown] section of &tdmrc;
This section contains global options concerning system shutdown.
The command (subject to word splitting) to run to halt/poweroff the system.
The default is something reasonable for the system on which &tdm; was built, like
/sbin/shutdown now.
The command (subject to word splitting) to run to reboot the system.
The default is something reasonable for the system &tdm; on which was built, like
/sbin/shutdown now.
Whether it is allowed to shut down the system via the global command FiFo.
The default is false.
Whether it is allowed to abort active sessions when shutting down the
system via the global command FiFo.
This will have no effect unless is enabled.
The default is true.
The boot manager &tdm; should use for offering boot options in the
shutdown dialog.
Noneno boot managerGrubGrub boot managerLiloLilo boot manager (Linux on i386 & x86-64 only)The default is None.The [X-*-Core] section class of &tdmrc;
This section class contains options concerning the configuration
of the &tdm; backend (core).
See .
The default is 15.
See .
The default is 120.
These options control the behavior of &tdm; when attempting to open a
connection to an &X-Server;. is the length
of the pause (in seconds) between successive attempts,
is the number of attempts to make and
is the amount of time to spend on a
connection attempt. After attempts have been
made, or if seconds elapse in any particular
connection attempt, the start attempt is considered failed.
The default is 5.
How many times &tdm; should attempt to start a foreign
display listed in before giving up
and disabling it.
Local displays are attempted only once, and &XDMCP; displays are retried
indefinitely by the client (unless the option
was given to the &X-Server;).
The default is 4.
How many times &tdm; should attempt to start up a local &X-Server;.
Starting up includes executing it and waiting for it to come up.
The default is 1.
How many seconds &tdm; should wait for a local &X-Server; to come up.
The default is 15.
The command line to start the &X-Server;, without display number and VT spec.
This string is subject to word splitting.
The default is something reasonable for the system on which &tdm; was built,
like /usr/X11R6/bin/X.
Additional arguments for the &X-Server;s for local sessions.
This string is subject to word splitting.
Empty by default.
Additional arguments for the &X-Server;s for remote sessions.
This string is subject to word splitting.
Empty by default.
The VT the &X-Server; should run on.
should be used instead of this option.
Leave it zero to let &tdm; assign a VT automatically.
Set it to -1 to avoid assigning a VT
alltogether - this is required for setups with multiple physical consoles.
Currently Linux only.
This option is for OSs without support for
VTs, either by &tdm; or the OS itself.
Currently this applies to all OSs but Linux.
When &tdm; switches to console mode, it starts monitoring this
TTY line (specified without the leading
/dev/) for activity. If the line is not used for some time,
&tdm; switches back to the X login.
Empty by default.
See .
The default is 5.
To discover when remote displays disappear, &tdm;
regularly pings them.
specifies the time (in minutes) between the
pings and 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.
If you frequently use X terminals which can become isolated from
the managing host, you may wish to increase the timeout. The only worry
is that sessions will continue to exist after the terminal has been
accidentally disabled.
The default is 5.
Whether &tdm; should restart the local &X-Server; after session exit instead
of resetting it. Use this if the &X-Server; leaks memory or crashes the system
on reset attempts.
The default is false.
The signal number to use to reset the local &X-Server;.
The default is 1 (SIGHUP).
The signal number to use to terminate the local &X-Server;.
The default is 15 (SIGTERM).
Controls whether &tdm; generates and uses authorization for
local &X-Server; connections.
For &XDMCP; displays the authorization requested by the display is used;
foreign non-&XDMCP; displays do not support authorization at all.
The default is true.
If is true, use the authorization mechanisms
listed herein. The MIT-MAGIC-COOKIE-1 authorization is always available;
XDM-AUTHORIZATION-1, SUN-DES-1 and MIT-KERBEROS-5 might be available as well,
depending on the build configuration.
The default is DEF_AUTH_NAME.
Some old &X-Server;s re-read the authorization file
at &X-Server; reset time, instead of when checking the initial connection.
As &tdm; generates the authorization information just before connecting to
the display, an old &X-Server; would not get up-to-date authorization
information. This option causes &tdm; to send SIGHUP to the &X-Server;
after setting up the file, causing an additional &X-Server; reset to occur,
during which time the new authorization information will be read.
The default is false.
This file is used to communicate the authorization data from &tdm; to
the &X-Server;, using the &X-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 &X-Server;. If not specified, a random name is generated from
and the name of the display.
Empty by default.
This option 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. KDE programs generally do not use
X-resources, so this option is only needed if the
program needs some X-resources.
Empty by default.
The xrdb program to use to read the X-resources file
specified in .
The command is subject to word splitting.
The default is ${x_bindir}/xrdb.
This string is subject to word splitting.
It specifies a program which is run (as
root) before offering the
greeter window. This may be used to change the appearance of the screen
around the greeter window or to put up other windows (e.g., you may want
to run xconsole here).
The conventional name for a program used here is Xsetup.
See .
Empty by default.
This string is subject to word splitting.
It specifies a program which is run (as
root) after the user
authentication process succeeds.
The conventional name for a program used here is Xstartup.
See .
Empty by default.
This string is subject to word splitting.
It specifies a program which is run (as
root) after the session
terminates.
The conventional name for a program used here is Xreset.
See .
Empty by default.
This string is subject to word splitting.
It specifies the session program to be executed (as the user owning
the session).
The conventional name for a program used here is Xsession.
See .
The default is ${x_bindir}/xterm -ls -T.
If the program fails to execute, &tdm; 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 default is ${x_bindir}/xterm.
The PATH environment variable for
non-root s.
The default depends on the system &tdm; was built on.
The PATH environment variable for all programs but
non-root
s. Note that it is good practice not to include
. (the current directory) into this entry.
The default depends on the system &tdm; was built on.
The SHELL environment variable for all programs but the
.
The default is /bin/sh.
When &tdm; is unable to write to the usual user authorization file
($HOME/.Xauthority), it creates a unique file name in this
directory and points the environment variable XAUTHORITY
at the created file.
The default is /tmp.
If enabled, &tdm; will automatically restart a session after an &X-Server;
crash (or if it is killed by Alt-Ctrl-BackSpace). Note that enabling this
feature opens a security hole: a secured display lock can be circumvented
(unless &tde;'s built-in screen locker is used).
The default is false.
If disabled, do not allow root
(and any other user with UID = 0) to log in directly.
The default is true.
If disabled, only users that have passwords assigned can log in.
The default is true.
Who is allowed to shut down the system. This applies both to the
greeter and to the command FiFo.
Noneno Shutdown... menu entry is shown at allRootthe root password must be entered to shut downAlleverybody can shut down the machineThe default is All.
Who is allowed to abort active sessions when shutting down.
Noneno forced shutdown is allowed at allRootthe root password must be entered to shut down forciblyAlleverybody can shut down the machine forciblyThe default is All.
The default choice for the shutdown condition/timing.
Scheduleshut down after all active sessions exit (possibly at once)TryNowshut down, if no active sessions are open; otherwise, do nothingForceNowshut down unconditionallyThe default is Schedule.
How to offer shutdown scheduling options:
Nevernot at allOptionalas a button in the simple shutdown dialogsAlwaysinstead of the simple shutdown dialogsThe default is Never.
Enable password-less logins on this display. Use with extreme care!The default is false.
The users that do not need to provide a password to log in.
Items which are prefixed with @ represent all users in the
user group named by that item.
* means all users but
root
(and any other user with UID = 0).
Never list root.
Empty by default.
Enable automatic login. Use with extreme care!The default is false.
If true, auto-login after logout. If false, auto-login is performed only
when a display session starts up.
The default is false.
The delay in seconds before automatic login kicks in. This is also known as
Timed Login.
The user to log in automatically. Never specify root!
Empty by default.
The password for the user to log in automatically. This is not required
unless the user is logged into a NIS or Kerberos domain. If you use this
option, you should chmod tdmrc for obvious reasons.
Empty by default.
Immediately lock the automatically started session. This works only with
KDE sessions.
The default is false.
A list of directories containing session type definitions.
The default is ${kde_datadir}/tdm/sessions.
The file (relative to the user's home directory) to redirect the session
output to. One occurrence of %s in this string will be
substituted with the display name. Use %% to obtain a
literal %.
The default is .xsession-errors.
Specify whether &tdm;'s built-in utmp/wtmp/lastlog registration should
be used. If it is not, the tool sessreg should be used
in the and scripts, or,
alternatively, the pam_lastlog module should be used on
PAM-enabled systems.
The default is true.The [X-*-Greeter] section class of &tdmrc;
This section class contains options concerning the configuration
of the &tdm; frontend (greeter).
Specify the widget style for the greeter. Empty means to use the
built-in default which currently is Plastik.
Empty by default.
Specify the widget color scheme for the greeter. Empty means to use
the built-in default which currently is yellowish grey with some light
blue and yellow elements.
Empty by default.
What should be shown in the greeter righthand of the input lines (if
is disabled) or above them (if
is enabled):
NonenothingLogothe image specified by Clocka neat analog clockThe default is Clock.
The image to show in the greeter if is
Logo.
Empty by default.
The relative coordinates (percentages of the screen size; X,Y) at which
the center of the greeter is put. &tdm; aligns the greeter to the edges
of the screen it would cross otherwise.
The default is 50,50.
The screen the greeter should be displayed on in multi-headed and Xinerama
setups. The numbering starts with 0. For Xinerama, it corresponds to the
listing order in the active ServerLayout section of XF86Config; -1 means
to use the upper-left screen, -2 means to use the upper-right screen.
The headline in the greeter. An empty greeting means none at all.
The following character pairs are replaced by their value:
%dname of the current display%hlocal host name, possibly with the
domain name%nlocal node name, most probably the host name without the
domain name%soperating system%roperating system version%mmachine (hardware) type%%a single %The default is Welcome to %s at %n.
Whether the fonts used in the greeter should be antialiased.
The default is false.
The font for the greeter headline.
The default is Serif,20,bold.
The normal font used in the greeter.
The default is Sans Serif,10.
The font used for the Login Failed message.
The default is Sans Serif,10,bold.
What to do with the Num Lock modifier for the time the greeter is running:
Offturn offOnturn onKeepdo not change the stateThe default is Keep.
Language and locale to use in the greeter, encoded like $LC_LANG.
The default is en_US.
Enable autocompletion in the username line edit.
The default is false.
Show a user list with login names, real names, and images in the greeter.
The default is true.
This option controls which users will be shown in the user view
() and/or offered for autocompletion
().
If it is Selected, contains
the final list of users.
If it is NotHidden, the initial user list contains all users
found on the system. Users contained in are
removed from the list, just like all users with a UID greater than specified
in and users with a non-zero UID less than
specified in .
Items in and
which are prefixed with @ represent all users in the
user group named by that item.
Finally, the user list will be sorted alphabetically, if
is enabled.
The default is NotHidden.
See .
Empty by default.
See .
Empty by default.
See .
See .
The default is 65535.
See .
The default is true.
If is enabled, this specifies where &tdm; gets the
images from:
AdminOnlyfrom <>/$USER.face[.icon]PreferAdminprefer <>, fallback on $HOMEPreferUser... and the other way roundUserOnlyfrom the user's $HOME/.face[.icon]
The images can be in any format Qt recognizes, but the filename
must match &tdm;'s expectations: .face.icon should be a
48x48 icon, while .face should be a 300x300 image.
Currently the big image is used only as a fallback and is scaled down,
but in the future it might be displayed full-size in the logo area or a
tooltip.
The default is AdminOnly.
See .
The default is ${kde_datadir}/tdm/faces.
Specify, if/which user should be preselected for log in:
Nonedo not preselect any userPreviousthe user which successfully logged in last timeDefaultthe user specified in the option
If is enabled and a user was preselected,
the cursor is placed in the password input field automatically.
Enabling user preselection can be considered a security hole,
as it presents a valid login name to a potential attacker, so he
only needs to guess the password. On the other hand,
one could set to a fake login name.The default is None.
See .
Empty by default.
See .
The default is false.
The password input fields cloak the typed in text. Specify, how to do it:
OneStar* is shown for every typed
characterThreeStars*** is shown for every typed
characterNoEchonothing is shown at all, the cursor does not moveThe default is OneStar.
If enabled, &tdm; will automatically start the krootimage
program to set up the background; otherwise, the
program is responsible for the background.
The default is true.
The configuration file to be used by krootimage.
It contains a section named [Desktop0] like
kdesktoprc does. Its options are not described
herein; guess their meanings or use the control center.
The default is ${kde_confdir}/tdm/backgroundrc.
To improve security, the greeter grabs the &X-Server; and then the keyboard
when it starts up. This option specifies if the &X-Server; grab should be held
for the duration of the name/password reading. When disabled, the &X-Server;
is ungrabbed after the keyboard grab succeeds; otherwise, the &X-Server; is
grabbed until just before the session begins.
Enabling this option disables and
.The default is false.
This option specifies the maximum time &tdm; will wait for the grabs to
succeed. A grab may fail if some other X-client has the &X-Server; or the
keyboard grabbed, or possibly if the network latencies are very high. You
should be cautious when raising the timeout, as a user can be spoofed by
a look-alike window on the display. If a grab fails, &tdm; kills and
restarts the &X-Server; (if possible) and the session.
The default is 3.
Warn, if a display has no X-authorization. This will be the case if
the authorization file for a local &X-Server; could not be created,
a remote display from &XDMCP; did not request any authorization or
the display is a foreign display specified in
.
The default is true.
Specify whether the greeter of local displays should start up in host chooser
(remote) or login (local) mode and whether it is allowed to switch to the
other mode.
LocalOnlyonly local login possibleDefaultLocalstart up in local mode, but allow switching to remote modeDefaultRemote... and the other way roundRemoteOnlyonly choice of remote host possibleThe default is LocalOnly.
A list of hosts to be automatically added to the remote login menu.
The special name * means broadcast.
Has no effect if is LocalOnly.
The default is *.
Use this number as a random seed when forging saved session types, etc. of
unknown users. This is used to avoid telling an attacker about existing users
by reverse conclusion. This value should be random but constant across the
login domain.
Enable &tdm;'s built-in xconsole.
Note that this can be enabled for only one display at a time.
This option is available only if &tdm; was configured
with .
The default is false.
The data source for &tdm;'s built-in xconsole.
If empty, a console log redirection is requested from
/dev/console.
Has no effect if is disabled.
Empty by default.
Specify conversation plugins for the login dialog; the first in the list
is selected initially.
Each plugin can be specified as a base name (which expands to
$kde_modulesdir/kgreet_base)
or as a full pathname.
Conversation plugins are modules for the greeter which obtain authentication
data from the user. Currently only the classic plugin is
shipped with &tde;; it presents the well-known username and password form.
The default is classic.
Same as , but for the shutdown dialog.
The default is classic.
A list of options of the form
Key=Value.
The conversation plugins can query these settings; it is up to them what
possible keys are.
Empty by default.
Show the Console Login action in the greeter (if /
is configured).
The default is true.
Show the Restart X Server/Close Connection action in the greeter.
The default is true.
A program to run while the greeter is visible. It is supposed to preload
as much as possible of the session that is going to be started (most
probably).
Empty by default.
Whether the greeter should be themed.
The default is false.
The theme to use for the greeter. Can point to either a directory or an XML
file.
Empty by default.Specifying permanent &X-Server;sEach entry in the list indicates a
display which should constantly be
managed and which is not using &XDMCP;. This method is typically used only for
local &X-Server;s that are started by &tdm;, but &tdm; can manage externally
started (foreign) &X-Server;s as well, may they run on the
local machine or rather remotely.The formal syntax of a specification is
display name [_display class]
for all &X-Server;s. Foreign displays differ in having
a host name in the display name, may it be localhost.The display name must be something that can
be passed in the option to an X program. This string
is used to generate the display-specific section names, so be careful to match
the names.
The display name of &XDMCP; displays is derived from the display's address by
reverse host name resolution. For configuration purposes, the
localhost prefix from locally running &XDMCP; displays is
not stripped to make them distinguishable from local
&X-Server;s started by &tdm;.The display class portion is also used in the
display-specific sections. This is useful if you have a large collection of
similar displays (such as a corral of X terminals) and would like to set
options for groups of them.
When using &XDMCP;, the display is required to specify the display class,
so the manual for your particular X terminal should document the display
class string for your device. If it does not, you can run &tdm; in debug
mode and grep the log for class.The displays specified in will not be
started when &tdm; starts up, but when it is explicitly requested via
the command socket (or FiFo).
If reserve displays are specified, the &tde; menu will have a
Start New Session item near the bottom; use that to
activate a reserve display with a new login session. The monitor will switch
to the new display, and you will have a minute to login. If there are no more
reserve displays available, the menu item will be disabled.When &tdm; starts a session, it sets up authorization data for the
&X-Server;. For local servers, &tdm; passes
filename
on the &X-Server;'s command line to point it at its authorization data.
For &XDMCP; displays, &tdm; passes the authorization data to the &X-Server;
via the Accept &XDMCP; message.&XDMCP; access controlThe file specified by the option provides
information which &tdm; uses to control access from displays requesting service
via &XDMCP;.
The file contains four types of entries: entries which control the response
to Direct and Broadcast queries, entries which
control the response to Indirect queries, macro definitions for
Indirect entries, and entries which control on which network
interfaces &tdm; listens for &XDMCP; queries.
Blank lines are ignored, # is treated as a comment
delimiter causing the rest of that line to be ignored, and \
causes an immediately following newline to be ignored, allowing indirect host
lists to span multiple lines.
The format of the Direct entries is simple, either a
host name or a pattern, which is compared against the host name of the display
device.
Patterns are distinguished from host names by the inclusion of one or more
meta characters; * matches any sequence of 0 or more
characters, and ? matches any single character.
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. Note
that only the first network address returned for a host name is used.
For patterns, only canonical host names are used in the comparison, so ensure
that you do not attempt to match aliases.
Host names from &XDMCP; queries always contain the local domain name
even if the reverse lookup returns a short name, so you can use
patterns for the local domain.
Preceding the entry 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 a &tdm; 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 the queries
should be forwarded. Indirect entries can be excluding as well,
in which case a (valid) dummy host name must be supplied to make the entry
distinguishable from a Direct entry.
If compiled with IPv6 support, multicast address groups may also be included
in the list of addresses the queries are forwarded to.
If the indirect host list contains the keyword CHOOSER,
Indirect queries are not forwarded, but instead a host chooser
dialog is displayed by &tdm;. The chooser will send a Direct
query to each of the remaining host names in the list and offer a menu of
all the hosts that respond. The host list may contain the keyword
BROADCAST, to make the chooser send a
Broadcast query as well; note that on some operating systems,
UDP packets cannot be broadcast, so this feature will not work.
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.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.The last entry type is the LISTEN directive.
The formal syntax is
LISTEN [interface [multicast list]]
If one or more LISTEN lines are specified, &tdm; listens
for &XDMCP; requests only on the specified interfaces.
interface may be a hostname or IP address
representing a network interface on this machine, or the wildcard
* to represent all available network interfaces.
If multicast group addresses are listed on a LISTEN line,
&tdm; joins the multicast groups on the given interface. For IPv6 multicasts,
the IANA has assigned ff0X:0:0:0:0:0:0:12b as the
permanently assigned range of multicast addresses for &XDMCP;. The
X in the prefix may be replaced by any valid scope
identifier, such as 1 for Node-Local, 2 for Link-Local, 5 for Site-Local, and
so on (see IETF RFC 2373 or its replacement for further details and scope
definitions). &tdm; defaults to listening on the Link-Local scope address
ff02:0:0:0:0:0:0:12b to most closely match the IPv4 subnet broadcast behavior.
If no LISTEN lines are given, &tdm; listens on all
interfaces and joins the default &XDMCP; IPv6 multicast group (when
compiled with IPv6 support).
To disable listening for &XDMCP; requests altogether, a
LISTEN line with no addresses may be specified, but using
the [Xdmcp] option is preferred.
Supplementary programs
The following programs are run by &tdm; at various stages of a session.
They typically are shell scripts.
The Setup, Startup and Reset programs are run as
root, so they should be careful
about security.
Their first argument is auto if the session results
from an automatic login; otherwise, no arguments are passed to them.
Setup program
The Xsetup program is run after the &X-Server; is
started or reset, but before the greeter is offered.
This is the place to change the root background (if
is disabled) or bring up other windows that
should appear on the screen along with the greeter.
In addition to any specified by ,
the following environment variables are passed:DISPLAYthe associated display namePATHthe value of SHELLthe value of XAUTHORITYmay be set to an authority fileDM_CONTROLthe value of Note that since &tdm; 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
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
.
Startup programThe Xstartup program is run as
root when the user logs in.
This is the place to put commands which add entries to
utmp (the sessreg program
may be useful here), mount users' home directories from file servers,
or abort the session if some requirements are not met (but note that on
modern systems, many of these tasks are already taken care of by
PAM modules).In addition to any specified by ,
the following environment variables are passed:DISPLAYthe associated display nameHOMEthe initial working directory of the userLOGNAMEthe usernameUSERthe usernamePATHthe value of SHELLthe value of XAUTHORITYmay be set to an authority fileDM_CONTROLthe value of &tdm; waits until this program exits before starting the user session.
If the exit value of this program is non-zero, &tdm; discontinues the session
and starts another authentication cycle.Session programThe Xsession program is the command which is run
as the user's session. It is run with the permissions of the authorized user.
One of the keywords failsafe, default
or custom, or a string to eval by a
Bourne-compatible shell is passed as the first argument.In addition to any specified by ,
the following environment variables are passed:DISPLAYthe associated display nameHOMEthe initial working directory of the userLOGNAMEthe usernameUSERthe usernamePATHthe value of
(or for
root user sessions)SHELLthe user's default shellXAUTHORITYmay be set to a non-standard authority fileKRBTTDEFILEmay be set to a Kerberos4 credentials cache nameKRB5CCNAMEmay be set to a Kerberos5 credentials cache nameDM_CONTROLthe value of XDM_MANAGEDwill contain a comma-separated list of parameters the
session might find interesting, like the location of the command
FiFo and its capabilities, and which conversation
plugin was used for the loginDESKTOP_SESSIONthe name of the session the user has chosen to runReset programSymmetrical with Xstartup, the
Xreset program is run after the user session has
terminated. Run as root, it should
contain commands that undo the effects of commands in
Xstartup, removing entries from utmp
or unmounting directories from file servers.The environment variables that were passed to
Xstartup are also passed to Xreset.