.TH XSERVER 1 "26 October 1988" "X Version 11" .SH NAME X - X Window System server .SH SYNOPSIS .B X [:displaynumber] [-option ...] [ttyname] .SH DESCRIPTION .I X is the generic name for the X Window System 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. The sample server from MIT supports the following platforms: .sp .ta 1.25in .in +4 .nf Xqvss Digital monochrome vaxstationII or II Xqdss Digital color vaxstationII or II Xsun Sun monochrome or color Sun 2, 3, or 4 Xhp HP Topcat 9000s300 Xapollo Apollo monochrome or color (Domain/OS SR10.1 or SR10.2) Xibm IBM APA and megapel PC/RT XmacII Apple monochrome Macintosh II Xplx Parallax color and video graphics controller .fi .in -4 .SH "STARTING THE SERVER" The server is usually started from the X Display Manager program \fIxdm\fP. 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. It is easily configured for sites that wish to provide nice, consistent interfaces for novice users (loading convenient sets of resources, starting up a window manager, clock, and nice selection of terminal emulator windows). .PP Since \fIxdm\fP now handles automatic starting of the server in a portable way, the \fI-L\fP option to \fIxterm\fP is now considered obsolete. Support for starting a login window from 4.3bsd-derived \fI/etc/ttys\fP files may not be included in future releases. .PP Installations that run more than one window system will still need to use the \fIxinit\fP utility. However, \fIxinit\fP is to be considered a tool for building startup scripts and is not intended for use by end users. Site adminstrators are \fBstrongly\fP urged to build nicer interfaces for novice users. .PP When the sample server starts up, it takes over the display. If you are running on a workstation whose console is the display, you cannot log into the console while the server is running. .SH "NETWORK CONNECTIONS" The sample server supports connections made using the following reliable byte-streams: .TP 4 .I TCP\/IP .br The server listens on port htons(6000+\fIn\fP), where \fIn\fP is the display number. .TP 4 .I "Unix Domain" The sample server uses \fI/tmp/.X11-unix/X\fBn\fR as the filename for the socket, where \fIn\fP is the display number. .TP 4 .I "DECnet" .br The server responds to connections to object \fIX$X\fBn\fR, where \fIn\fP is the display number. .SH OPTIONS All of the sample servers accept the following command line options: .TP 8 .B \-a \fInumber\fP sets pointer acceleration (i.e. the ratio of how much is reported to how much the user actually moved the pointer). .TP 8 .B \-auth \fIauthorization-file\fP Specifies a file which contains a collection of authorization records used to authenticate access. .TP 8 .B bc disables certain kinds of error checking, for bug compatibility with previous releases (e.g., to work around bugs in R2 and R3 xterms and toolkits). Deprecated. .TP 8 .B \-bs disables backing store support on all screens. .TP 8 .B \-c turns off key-click. .TP 8 .B c \fIvolume\fP sets key-click volume (allowable range: 0-100). .TP 8 .B -cc \fIclass\fP 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. .TP 8 .B \-co \fIfilename\fP sets name of RGB color database. .TP 8 .B \-dpi \fIresolution\fP sets the resolution of the screen, in dots per inch. To be used when the server cannot determine the screen size from the hardware. .TP 8 .B \-f \fIvolume\fP sets feep (bell) volume (allowable range: 0-100). .TP 8 .B \-fc \fIcursorFont\fP sets default cursor font. .TP 8 .B \-fn \fIfont\fP sets the default font. .TP 8 .B \-fp \fIfontPath sets the search path for fonts. .TP 8 .B \-help prints a usage message. .TP 8 .B \-I causes all remaining command line arguments to be ignored. .TP 8 .B \-ld \fIkilobytes\fP sets the data space limit of the server to the specified number of kilobytes. The default value is zero, making the data size as large as possible. A value of -1 leaves the data space limit unchanged. This option is not available in all operating systems. .TP 8 .B \-ls \fIkilobytes\fP sets the stack space limit of the server to the specified number of kilobytes. The default value is zero, making the stack size as large as possible. A value of -1 leaves the stack space limit unchanged. This option is not available in all operating systems. .TP 8 .B \-logo turns on the X Window System logo display in the screen-saver. There is currently no way to change this from a client. .TP 8 .B nologo turns off the X Window System logo display in the screen-saver. There is currently no way to change this from a client. .TP 8 .B \-p \fIminutes\fP sets screen-saver pattern cycle time in minutes. .TP 8 .B \-r turns off auto-repeat. .TP 8 .B r turns on auto-repeat. .TP 8 .B \-s \fIminutes\fP sets screen-saver timeout time in minutes. .TP 8 .B \-su disables save under support on all screens. .TP 8 .B \-t \fInumbers\fP sets pointer acceleration threshold in pixels (i.e. after how many pixels pointer acceleration should take effect). .TP 8 .B \-to \fIseconds\fP sets default connection timeout in seconds. .TP 8 .B tty\fIxx\fP ignored, for servers started the ancient way (from init). .TP 8 .B v sets video-on screen-saver preference. .TP 8 .B \-v sets video-off screen-saver preference. .TP 8 .B \-wm forces the default backing-store of all windows to be WhenMapped; a cheap trick way of getting backing-store to apply to all windows. .TP 8 .B \-x \fIextension\fP loads the specified extension at init. Not supported in most implementations. .PP Many servers also have device-specific command line options. See the manual pages for the individual servers for more details. .SH "SECURITY" .PP The sample server implements a simplistic authorization protocol which uses data private to authorized clients and the server. The authorzation data is passed to the server in a private file named with the \fB-auth\fP command line option. 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. The authorization name supported is "MIT-MAGIC-COOKIE-1". See the \fIXau\fP manual page for a description of the binary format of this file. Maintenence of this file, and distribution of its contents to remote sites for use there is left as an exercise for the reader. .PP The sample server also uses a host-based access control list for deciding whether or not to accept connections from clients on a particular machine. This list initially consists of the host on which the server is running as well as any machines listed in the file \fI/etc/X\fBn\fI.hosts\fR, where \fBn\fP 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 DECnet hostname in double colon format (e.g. hydra::). There should be no leading or trailing spaces on any lines. For example: .sp .in +8 .nf joesworkstation corporate.company.com star:: bigcpu:: .fi .in -8 .PP Users can add or remove hosts from this list and enable or disable access control using the \fIxhost\fP command from the same machine as the server. For example: .sp .in +8 .nf % xhost +janesworkstation janesworkstation being added to access control list % xhost -star:: public:: being removed from access control list % xhost + all hosts being allowed (access control disabled) % xhost - all hosts being restricted (access control enabled) % xhost access control enabled (only the following hosts are allowed) joesworkstation janesworkstation corporate.company.com bigcpu:: .fi .in -8 .PP Unlike some window systems, X 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. Sites that have better authentication and authorization systems (such as Kerberos) might wish to make use of the hooks in the libraries and the server to provide additional security models. .SH "SIGNALS" The sample server attaches special meaning to the following signals: .TP 8 .I 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 \fIxterm\fP or window manager) exits to force the server to clean up and prepare for the next user. .TP 8 .I SIGTERM This signal causes the server to exit cleanly. .SH "FONTS" Fonts are usually stored as individual files in directories. The list of directories in which the server looks when trying to open a font is controlled by the \fIfont path\fP. Although most sites will choose to have the server start up with the appropriate font path (using the \fI-fp\fP option mentioned above), it can be overridden using the \fIxset\fP program. .PP The default font path for the sample server contains three directories: .TP 8 .I /usr/lib/X11/fonts/misc This directory contains several miscellaneous fonts that are useful on all systems. It contains a very small family of fixed-width fonts (\fB6x10\fP, \fB6x12\fP, \fB6x13\fP, \fB8x13\fP, \fB8x13bold\fP, and \fB9x15\fP) and the cursor font. It also has font name aliases for the commonly used fonts \fBfixed\fP and \fBvariable\fP. .TP 8 .I /usr/lib/X11/fonts/75dpi This directory contains fonts contributed by Adobe Systems, Inc. and Digital Equipment Corporation and by Bitstream, Inc. for 75 dots per inch displays. An integrated selection of sizes, styles, and weights are provided for each family. .TP 8 .I /usr/lib/X11/fonts/100dpi This directory contains versions of some of the fonts in the \fI75dpi\fP directory for 100 dots per inch displays. .PP Font databases are created by running the \fImkfontdir\fP program in the directory containing the compiled versions of the fonts (the \fI.snf\fP files). Whenever fonts are added to a directory, \fImkfontdir\fP should be rerun so that the server can find the new fonts. \fBIf \fImkfontdir\fP is not run, the server will not be able to find any fonts in the directory.\fR .SH DIAGNOSTICS Too numerous to list them all. If run from \fIinit(8)\fP, errors are logged in the file \fI/usr/adm/X*msgs\fP, .SH FILES .TP 30 /etc/X*.hosts Initial access control list .TP 30 /usr/lib/X11/fonts/misc, /usr/lib/X11/fonts/75dpi, /usr/lib/X11/fonts/100dpi Font directories .TP 30 /usr/lib/X11/rgb.txt Color database .TP 30 /tmp/.X11-unix/X* Unix domain socket .TP 30 /usr/adm/X*msgs Error log file .SH "SEE ALSO" X(1), xdm(1), mkfontdir(1), xinit(1), xterm(1), twm(1), xhost(1), xset(1), xsetroot(1), ttys(5), init(8), Xqdss(1), Xqvss(1), Xsun(1), Xapollo(1), XmacII(1) .I "X Window System Protocol," .I "Definition of the Porting Layer for the X v11 Sample Server," .I "Strategies for Porting the X v11 Sample Server," .I "Godzilla's Guide to Porting the X V11 Sample Server" .SH BUGS The option syntax is inconsistent with itself and \fIxset(1)\fP. .PP The acceleration option should take a numerator and a denominator like the protocol. .PP If .I X dies before its clients, new clients won't be able to connect until all existing connections have their TCP TIME_WAIT timers expire. .PP The color database is missing a large number of colors. However, there doesn't seem to be a better one available that can generate RGB values tailorable to particular displays. .PP The \fIxterm -L\fP method for starting an initial window from \fI/etc/ttys\fP is completely inadequate and should be removed. People should use \fIxdm\fP instead. .SH COPYRIGHT Copyright 1984, 1985, 1986, 1987, 1988, Massachusetts Institute of Technology. .br See \fIX(1)\fP for a full statement of rights and permissions. .SH AUTHORS The sample server was originally written by Susan Angebranndt, Raymond Drewry, Philip Karlton, and Todd Newman, with support from a cast of thouands. See also the file \fIdoc/contributors\fP in the sample distribution for a more complete list.