Xserver

XSERVER(1)                   General Commands Manual                  XSERVER(1)



NAME
       Xserver - X Window System display server

SYNOPSIS
       X [option ...]

DESCRIPTION
       X is the generic name for the X Window System display server.  It is
       frequently a link or a copy of the appropriate server binary for driving
       the most frequently used server on a given machine.

STARTING THE SERVER
       The X server is usually started from the X Display Manager program xdm(1)
       or a similar display manager program.  This utility is run from the
       system boot files and takes care of keeping the server running, prompting
       for usernames and passwords, and starting up the user sessions.

       Installations that run more than one window system may need to use the
       xinit(1) utility instead of a display manager.  However, xinit is to be
       considered a tool for building startup scripts and is not intended for
       use by end users.  Site administrators are strongly urged to use a
       display manager, or build other interfaces for novice users.

       The X server may also be started directly by the user, though this method
       is usually reserved for testing and is not recommended for normal
       operation.  On some platforms, the user must have special permission to
       start the X server, often because access to certain devices (e.g.
       /dev/mouse) is restricted.

       When the X server starts up, it typically takes over the display.  If you
       are running on a workstation whose console is the display, you may not be
       able to log into the console while the server is running.

OPTIONS
       Many X servers have device-specific command line options.  See the manual
       pages for the individual servers for more details; a list of server-
       specific manual pages is provided in the SEE ALSO section below.

       All of the X servers accept the command line options described below.
       Some X servers may have alternative ways of providing the parameters
       described here, but the values provided via the command line options
       should override values specified via other mechanisms.

       :displaynumber
               The X server runs as the given displaynumber, which by default is
               0.  If multiple X servers are to run simultaneously on a host,
               each must have a unique display number.  See the DISPLAY NAMES
               section of the X(7) manual page to learn how to specify which
               display number clients should try to use.

       -a number
               sets pointer acceleration (i.e. the ratio of how much is reported
               to how much the user actually moved the pointer).

       -ac     disables host-based access control mechanisms.  Enables access by
               any host, and permits any host to modify the access control list.
               Use with extreme caution.  This option exists primarily for
               running test suites remotely.

       -audit level
               sets the audit trail level.  The default level is 1, meaning only
               connection rejections are reported.  Level 2 additionally reports
               all successful connections and disconnects.  Level 4 enables
               messages from the SECURITY extension, if present, including
               generation and revocation of authorizations and violations of the
               security policy.  Level 0 turns off the audit trail.  Audit lines
               are sent as standard error output.

       -auth authorization-file
               specifies a file which contains a collection of authorization
               records used to authenticate access.  See also the xdm(1) and
               Xsecurity(7) manual pages.

       -background none
               Asks the driver not to clear the background on startup, if the
               driver supports that.  May be useful for smooth transition with
               eg. fbdev driver.  For security reasons this is not the default
               as the screen contents might show a previous user session.

       -br     sets the default root window to solid black instead of the
               standard root weave pattern.   This is the default unless -retro
               or -wr is specified.

       -bs     disables backing store support on all screens.

       -c      turns off key-click.

       c volume
               sets key-click volume (allowable range: 0-100).

       -cc class
               sets the visual class for the root window of color screens.  The
               class numbers are as specified in the X protocol.  Not obeyed by
               all servers.

       -core   causes the server to generate a core dump on fatal errors.

       -displayfd fd
               specifies a file descriptor in the launching process.  Rather
               than specify a display number, the X server will attempt to
               listen on successively higher display numbers, and upon finding a
               free one, will write the display number back on this file
               descriptor as a newline-terminated string.  The -pn option is
               ignored when using -displayfd.

       -deferglyphs whichfonts
               specifies the types of fonts for which the server should attempt
               to use deferred glyph loading.  whichfonts can be all (all
               fonts), none (no fonts), or 16 (16 bit fonts only).

       -dpi resolution
               sets the resolution for all screens, in dots per inch.  To be
               used when the server cannot determine the screen size(s) from the
               hardware.

       dpms    enables DPMS (display power management services), where
               supported.  The default state is platform and configuration
               specific.

       -dpms   disables DPMS (display power management services).  The default
               state is platform and configuration specific.

       -extensionextensionName
               disables named extension.   If an unknown extension name is
               specified, a list of accepted extension names is printed.

       +extensionextensionName
               enables named extension.   If an unknown extension name is
               specified, a list of accepted extension names is printed.

       -f volume
               sets beep (bell) volume (allowable range: 0-100).

       -fc cursorFont
               sets default cursor font.

       -fn font
               sets the default font.

       -fp fontPath
               sets the search path for fonts.  This path is a comma separated
               list of directories which the X server searches for font
               databases.  See the FONTS section of this manual page for more
               information and the default list.

       -help   prints a usage message.

       -I      causes all remaining command line arguments to be ignored.

       -iglx   Prohibit creating indirect GLX contexts.  Indirect GLX is of
               limited use, since it lacks support for many modern OpenGL
               features and extensions; it's slower than direct contexts; and it
               opens a large attack surface for protocol parsing errors.  This
               is the default unless +iglx is specified.

       +iglx   Allow creating indirect GLX contexts.

       -maxbigreqsize size
               sets the maximum big request to size MB.

       -nocursor
               disable the display of the pointer cursor.

       -nolisten trans-type
               disables a transport type.  For example, TCP/IP connections can
               be disabled with -nolisten tcp.  This option may be issued
               multiple times to disable listening to different transport types.
               Supported transport types are platform dependent, but commonly
               include:

               tcp     TCP over IPv4 or IPv6
               inet    TCP over IPv4 only
               inet6   TCP over IPv6 only
               unix    UNIX Domain Sockets
               local   Platform preferred local connection method

       -listen trans-type
               enables a transport type.  For example, TCP/IP connections can be
               enabled with -listen tcp.  This option may be issued multiple
               times to enable listening to different transport types.

       -noreset
               prevents a server reset when the last client connection is
               closed.  This overrides a previous -terminate command line
               option.

       -p minutes
               sets screen-saver pattern cycle time in minutes.

       -pn     permits the server to continue running if it fails to establish
               all of its well-known sockets (connection points for clients),
               but establishes at least one.  This option is set by default.

       -nopn   causes the server to exit if it fails to establish all of its
               well-known sockets (connection points for clients).

       -r      turns off auto-repeat.

       r       turns on auto-repeat.

       -retro  starts the server with the classic stipple and cursor visible.
               The default is to start with a black root window, and to suppress
               display of the cursor until the first time an application calls
               XDefineCursor(). For kdrive servers, this implies -zap.

       -s minutes
               sets screen-saver timeout time in minutes.

       -su     disables save under support on all screens.

       -seat seat
               seat to run on. Takes a string identifying a seat in a platform
               specific syntax. On platforms which support this feature this may
               be used to limit the server to expose only a specific subset of
               devices connected to the system.

       -t number
               sets pointer acceleration threshold in pixels (i.e. after how
               many pixels pointer acceleration should take effect).

       -terminate
               causes the server to terminate at server reset, instead of
               continuing to run.  This overrides a previous -noreset command
               line option.

       -to seconds
               sets default connection timeout in seconds.

       -tst    disables all testing extensions (e.g., XTEST, XTrap,
               XTestExtension1, RECORD).

       ttyxx   ignored, for servers started the ancient way (from init).

       v       sets video-off screen-saver preference.

       -v      sets video-on screen-saver preference.

       -wm     forces the default backing-store of all windows to be WhenMapped.
               This is a backdoor way of getting backing-store to apply to all
               windows.  Although all mapped windows will have backing store,
               the backing store attribute value reported by the server for a
               window will be the last value established by a client.  If it has
               never been set by a client, the server will report the default
               value, NotUseful.  This behavior is required by the X protocol,
               which allows the server to exceed the client's backing store
               expectations but does not provide a way to tell the client that
               it is doing so.

       -wr     sets the default root window to solid white instead of the
               standard root weave pattern.

       -x extension
               loads the specified extension at init.  This is a no-op for most
               implementations.

       [+-]xinerama
               enables(+) or disables(-) the XINERAMA extension.  The default
               state is platform and configuration specific.

SERVER DEPENDENT OPTIONS
       Some X servers accept the following options:

       -ld kilobytes
               sets the data space limit of the server to the specified number
               of kilobytes.  A value of zero makes the data size as large as
               possible.  The default value of -1 leaves the data space limit
               unchanged.

       -lf files
               sets the number-of-open-files limit of the server to the
               specified number.  A value of zero makes the limit as large as
               possible.  The default value of -1 leaves the limit unchanged.

       -ls kilobytes
               sets the stack space limit of the server to the specified number
               of kilobytes.  A value of zero makes the stack size as large as
               possible.  The default value of -1 leaves the stack space limit
               unchanged.

       -maxclients
               64|128|256|512 Set the maximum number of clients allowed to
               connect to the X server.  Acceptable values are 64, 128, 256 or
               512.

       -render default|mono|gray|color sets the color allocation policy that
               will be used by the render extension.

               default selects the default policy defined for the display depth
                       of the X server.

               mono    don't use any color cell.

               gray    use a gray map of 13 color cells for the X render
                       extension.

               color   use a color cube of at most 4*4*4 colors (that is 64
                       color cells).

       -dumbSched
               disables smart scheduling on platforms that support the smart
               scheduler.

       -schedInterval interval
               sets the smart scheduler's scheduling interval to interval
               milliseconds.

XDMCP OPTIONS
       X servers that support XDMCP have the following options.  See the X
       Display Manager Control Protocol specification for more information.

       -query hostname
               enables XDMCP and sends Query packets to the specified hostname.

       -broadcast
               enable XDMCP and broadcasts BroadcastQuery packets to the
               network.  The first responding display manager will be chosen for
               the session.

       -multicast [address [hop count]]
               Enable XDMCP and multicast BroadcastQuery packets to the
               network.  The first responding display manager is chosen for the
               session.  If an address is specified, the multicast is sent to
               that address.  If no address is specified, the multicast is sent
               to the default XDMCP IPv6 multicast group.  If a hop count is
               specified, it is used as the maximum hop count for the multicast.
               If no hop count is specified, the multicast is set to a maximum
               of 1 hop, to prevent the multicast from being routed beyond the
               local network.

       -indirect hostname
               enables XDMCP and send IndirectQuery packets to the specified
               hostname.

       -port port-number
               uses the specified port-number for XDMCP packets, instead of the
               default.  This option must be specified before any -query,
               -broadcast, -multicast, or -indirect options.

       -from local-address
               specifies the local address to connect from (useful if the
               connecting host has multiple network interfaces).  The local-
               address may be expressed in any form acceptable to the host
               platform's gethostbyname(3) implementation.

       -once   causes the server to terminate (rather than reset) when the XDMCP
               session ends.

       -class display-class
               XDMCP has an additional display qualifier used in resource lookup
               for display-specific options.  This option sets that value, by
               default it is "MIT-unspecified" (not a very useful value).

       -cookie xdm-auth-bits
               When testing XDM-AUTHENTICATION-1, a private key is shared
               between the server and the manager.  This option sets the value
               of that private data (not that it is very private, being on the
               command line!).

       -displayID display-id
               Yet another XDMCP specific value, this one allows the display
               manager to identify each display so that it can locate the shared
               key.

XKEYBOARD OPTIONS
       X servers that support the XKEYBOARD (a.k.a. "XKB") extension accept the
       following options.  All layout files specified on the command line must
       be located in the XKB base directory or a subdirectory, and specified as
       the relative path from the XKB base directory.  The default XKB base
       directory is /usr/lib/X11/xkb.

       [+-]accessx [ timeout [ timeout_mask [ feedback [ options_mask ] ] ] ]
               enables(+) or disables(-) AccessX key sequences.

       -xkbdir directory
               base directory for keyboard layout files.  This option is not
               available for setuid X servers (i.e., when the X server's real
               and effective uids are different).

       -ardelay milliseconds
               sets the autorepeat delay (length of time in milliseconds that a
               key must be depressed before autorepeat starts).

       -arinterval milliseconds
               sets the autorepeat interval (length of time in milliseconds that
               should elapse between autorepeat-generated keystrokes).

       -xkbmap filename
               loads keyboard description in filename on server startup.

NETWORK CONNECTIONS
       The X server supports client connections via a platform-dependent subset
       of the following transport types: TCP/IP, Unix Domain sockets, and
       several varieties of SVR4 local connections.  See the DISPLAY NAMES
       section of the X(7) manual page to learn how to specify which transport
       type clients should try to use.

GRANTING ACCESS
       The X server implements a platform-dependent subset of the following
       authorization protocols: MIT-MAGIC-COOKIE-1, XDM-AUTHORIZATION-1, XDM-
       AUTHORIZATION-2, SUN-DES-1, and MIT-KERBEROS-5.  See the Xsecurity(7)
       manual page for information on the operation of these protocols.

       Authorization data required by the above protocols is passed to the
       server in a private file named with the -auth command line option.  Each
       time the server is about to accept the first connection after a reset (or
       when the server is starting), it reads this file.  If this file contains
       any authorization records, the local host is not automatically allowed
       access to the server, and only clients which send one of the
       authorization records contained in the file in the connection setup
       information will be allowed access.  See the Xau manual page for a
       description of the binary format of this file.  See xauth(1) for
       maintenance of this file, and distribution of its contents to remote
       hosts.

       The X server also uses a host-based access control list for deciding
       whether or not to accept connections from clients on a particular
       machine.  If no other authorization mechanism is being used, this list
       initially consists of the host on which the server is running as well as
       any machines listed in the file /etc/Xn.hosts, where n is the display
       number of the server.  Each line of the file should contain either an
       Internet hostname (e.g. expo.lcs.mit.edu) or a complete name in the
       format family:name as described in the xhost(1) manual page.  There
       should be no leading or trailing spaces on any lines.  For example:

               joesworkstation
               corporate.company.com
               inet:bigcpu
               local:

       Users can add or remove hosts from this list and enable or disable access
       control using the xhost command from the same machine as the server.

       If the X FireWall Proxy (xfwp) is being used without a sitepolicy, host-
       based authorization must be turned on for clients to be able to connect
       to the X server via the xfwp.  If xfwp is run without a configuration
       file and thus no sitepolicy is defined, if xfwp is using an X server
       where xhost + has been run to turn off host-based authorization checks,
       when a client tries to connect to this X server via xfwp, the X server
       will deny the connection.  See xfwp(1) for more information about this
       proxy.

       The X protocol intrinsically does not have any notion of window operation
       permissions or place any restrictions on what a client can do; if a
       program can connect to a display, it has full run of the screen.  X
       servers that support the SECURITY extension fare better because clients
       can be designated untrusted via the authorization they use to connect;
       see the xauth(1) manual page for details.  Restrictions are imposed on
       untrusted clients that curtail the mischief they can do.  See the
       SECURITY extension specification for a complete list of these
       restrictions.

       Sites that have better authentication and authorization systems might
       wish to make use of the hooks in the libraries and the server to provide
       additional security models.

SIGNALS
       The X server attaches special meaning to the following signals:

       SIGHUP  This signal causes the server to close all existing connections,
               free all resources, and restore all defaults.  It is sent by the
               display manager whenever the main user's main application
               (usually an xterm or window manager) exits to force the server to
               clean up and prepare for the next user.

       SIGTERM This signal causes the server to exit cleanly.

       SIGUSR1 This signal is used quite differently from either of the above.
               When the server starts, it checks to see if it has inherited
               SIGUSR1 as SIG_IGN instead of the usual SIG_DFL.  In this case,
               the server sends a SIGUSR1 to its parent process after it has set
               up the various connection schemes.  Xdm uses this feature to
               recognize when connecting to the server is possible.

FONTS
       The X server can obtain fonts from directories and/or from font servers.
       The list of directories and font servers the X server uses when trying to
       open a font is controlled by the font path.

       The default font path is
       /usr/share/fonts/misc,/usr/share/fonts/TTF,/usr/share/fonts/OTF,/usr/share/fonts/Type1,/usr/share/fonts/100dpi,/usr/share/fonts/75dpi
       .

       A special kind of directory can be specified using the catalogue: prefix.
       Directories specified this way can contain symlinks pointing to the real
       font directories. See the FONTPATH.D section for details.

       The font path can be set with the -fp option or by xset(1) after the
       server has started.

FONTPATH.D
       You can specify a special kind of font path in the form catalogue:<dir>.
       The directory specified after the catalogue: prefix will be scanned for
       symlinks and each symlink destination will be added as a local fontfile
       FPE.

       The symlink can be suffixed by attributes such as 'unscaled', which will
       be passed through to the underlying fontfile FPE. The only exception is
       the newly introduced 'pri' attribute, which will be used for ordering the
       font paths specified by the symlinks.

       An example configuration:

           75dpi:unscaled:pri=20 -> /usr/share/X11/fonts/75dpi
           ghostscript:pri=60 -> /usr/share/fonts/default/ghostscript
           misc:unscaled:pri=10 -> /usr/share/X11/fonts/misc
           type1:pri=40 -> /usr/share/X11/fonts/Type1
           type1:pri=50 -> /usr/share/fonts/default/Type1

       This will add /usr/share/X11/fonts/misc as the first FPE with the
       attribute 'unscaled', second FPE will be /usr/share/X11/fonts/75dpi, also
       with the attribute 'unscaled' etc. This is functionally equivalent to
       setting the following font path:

           /usr/share/X11/fonts/misc:unscaled,
           /usr/share/X11/fonts/75dpi:unscaled,
           /usr/share/X11/fonts/Type1,
           /usr/share/fonts/default/Type1,
           /usr/share/fonts/default/ghostscript


FILES
       /etc/Xn.hosts                 Initial access control list for display
                                     number n

       /usr/share/fonts/X11/misc,/usr/share/fonts/X11/75dpi,/usr/share/fonts/X11/100dpi
                                     Bitmap font directories

       /usr/share/fonts/X11/TTF,/usr/share/fonts/X11/Type1
                                     Outline font directories

       /tmp/.X11-unix/Xn             Unix domain socket for display number n

       /usr/adm/Xnmsgs               Error log file for display number n if run
                                     from init(8)

       /usr/lib/X11/xdm/xdm-errors   Default error log file if the server is run
                                     from xdm(1)

SEE ALSO
       General information: X(7)

       Protocols: X Window System Protocol, The X Font Service Protocol, X
       Display Manager Control Protocol

       Fonts: bdftopcf(1), mkfontdir(1), mkfontscale(1), xfs(1), xlsfonts(1),
       xfontsel(1), xfd(1), X Logical Font Description Conventions

       Keyboards: xkeyboard-config(7)

       Security: Xsecurity(7), xauth(1), Xau(1), xdm(1), xhost(1), xfwp(1),
       Security Extension Specification

       Starting the server: startx(1), xdm(1), xinit(1)

       Controlling the server once started: xset(1), xsetroot(1), xhost(1),
       xinput(1), xrandr(1)

       Server-specific man pages: Xorg(1), Xdmx(1), Xephyr(1), Xnest(1),
       Xvfb(1), Xquartz(1), XWin(1).

       Server internal documentation: Definition of the Porting Layer for the X
       v11 Sample Server

AUTHORS
       The sample server was originally written by Susan Angebranndt, Raymond
       Drewry, Philip Karlton, and Todd Newman, from Digital Equipment
       Corporation, with support from a large cast.  It has since been
       extensively rewritten by Keith Packard and Bob Scheifler, from MIT.  Dave
       Wiggins took over post-R5 and made substantial improvements.



X Version 11                   xorg-server 1.20.10                    XSERVER(1)