XSERVER(1) USER COMMANDS XSERVER(1) NAME Xserver - X Window System server SYNOPSIS X [:displaynumber] [-option ...] [ttyname] DESCRIPTION _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. STARTING THE SERVER The server is usually started from the X Display Manager program _x_d_m. 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). Installations that run more than one window system will still need to use the _x_i_n_i_t utility. However, _x_i_n_i_t 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 _x_d_m, or build other interfaces for novice users. When the X 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. NETWORK CONNECTIONS The X server supports connections made using the following reliable byte-streams: _T_C_P/_I_P The server listens on port 6000+_n, where _n is the display number. _U_n_i_x _D_o_m_a_i_n The X server uses /_t_m_p/._X_1_1-_u_n_i_x/_Xn as the filename for the socket, where _n is the display number. _D_E_C_n_e_t The server responds to connections to object _X$_Xn, where _n is the display number. This is not supported in all environments. X Version 11 Last change: Release 5 1 XSERVER(1) USER COMMANDS XSERVER(1) OPTIONS All of the X servers accept the following command line options: -a _n_u_m_b_e_r sets pointer acceleration (i.e. the ratio of how much is reported to how much the user actually moved the pointer). -auth _a_u_t_h_o_r_i_z_a_t_i_o_n-_f_i_l_e Specifies a file which contains a collection of authorization records used to authenticate access. See also the _x_d_m and _X_s_e_c_u_r_i_t_y manual pages. 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. -bs disables backing store support on all screens. -c turns off key-click. c _v_o_l_u_m_e sets key-click volume (allowable range: 0-100). -cc _c_l_a_s_s 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. -co _f_i_l_e_n_a_m_e sets name of RGB color database. -dpi _r_e_s_o_l_u_t_i_o_n sets the resolution of the screen, in dots per inch. To be used when the server cannot determine the screen size from the hardware. -f _v_o_l_u_m_e sets feep (bell) volume (allowable range: 0-100). -fc _c_u_r_s_o_r_F_o_n_t sets default cursor font. -fn _f_o_n_t sets the default font. -fp _f_o_n_t_P_a_t_h sets the search path for fonts. This path is a comma separated list of directories which the X server searches for font databases. X Version 11 Last change: Release 5 2 XSERVER(1) USER COMMANDS XSERVER(1) -help prints a usage message. -I causes all remaining command line arguments to be ignored. -ld _k_i_l_o_b_y_t_e_s 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. This option is not available in all operating systems. -lf _f_i_l_e_s sets the number-of-open-files limit of the server to the specified number. A value is zero makes the limit as large as possible. The default value of -1 leaves the limit unchanged. This option is not available in all operating systems. -ls _k_i_l_o_b_y_t_e_s 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. This option is not available in all operating systems. -logo turns on the X Window System logo display in the screen-saver. There is currently no way to change this from a client. nologo turns off the X Window System logo display in the screen-saver. There is currently no way to change this from a client. -p _m_i_n_u_t_e_s sets screen-saver pattern cycle time in minutes. -r turns off auto-repeat. r turns on auto-repeat. -s _m_i_n_u_t_e_s sets screen-saver timeout time in minutes. -su disables save under support on all screens. -t _n_u_m_b_e_r sets pointer acceleration threshold in pixels (i.e. after how many pixels pointer acceleration should take effect). X Version 11 Last change: Release 5 3 XSERVER(1) USER COMMANDS XSERVER(1) -to _s_e_c_o_n_d_s sets default connection timeout in seconds. tty_x_x 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; a cheap trick way of getting backing-store to apply to all windows. -x _e_x_t_e_n_s_i_o_n loads the specified extension at init. Not sup- ported in most implementations. You can also have the X server connect to _x_d_m using XDMCP. Although this is not typically useful as it does not allow _x_d_m to manage the server process, it can be used to debug XDMCP implementations, and serves as a sample implementation of the server side of XDMCP. For more information on this protocol, see the _X _D_i_s_p_l_a_y _M_a_n_a_g_e_r _C_o_n_t_r_o_l _P_r_o_t_o_c_o_l specif- ication. The following options control the behavior of XDMCP. -query _h_o_s_t-_n_a_m_e Enable XDMCP and send Query packets to the specified host. -broadcast Enable XDMCP and broadcast BroadcastQuery packets to the network. The first responding display manager will be chosen for the session. -indirect _h_o_s_t-_n_a_m_e Enable XDMCP and send IndirectQuery packets to the specified host. -port _p_o_r_t-_n_u_m Use an alternate port number for XDMCP packets. Must be specified before any -query, -broadcast or -indirect options. -once Normally, the server keeps starting sessions, one after the other. This option makes the server exit after the first session is over. -class _d_i_s_p_l_a_y-_c_l_a_s_s XDMCP has an additional display qualifier used in resource lookup for display-specific options. This X Version 11 Last change: Release 5 4 XSERVER(1) USER COMMANDS XSERVER(1) option sets that value, by default it is "MIT- Unspecified" (not a very useful value). -cookie _x_d_m-_a_u_t_h-_b_i_t_s 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 _d_i_s_p_l_a_y-_i_d Yet another XDMCP specific value, this one allows the display manager to identify each display so that it can locate the shared key. Many servers also have device-specific command line options. See the manual pages for the individual servers for more details. SECURITY The X server implements a simplistic authorization protocol, MIT-MAGIC-COOKIE-1 which uses data private to authorized clients and the server. This is a rather trivial scheme; if the client passes authorization data which is the same as the server has, it is allowed access. This scheme is worse than the host-based access control mechanisms in environ- ments with unsecure networks as it allows any host to con- nect, given that it has discovered the private key. But in many environments, this level of security is better than the host-based scheme as it allows access control per-user instead of per-host. In addition, the server provides support for a DES-based authorization scheme, XDM-AUTHORIZATION-1, which is more secure (given a secure key distribution mechanism). This authorization scheme can be used in conjunction with XDMCP's authentication scheme (XDM-AUTHENTICATION-1) or in isola- tion. The authorization data 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 _X_a_u manual page for a description of the binary format of this file. Maintenance of this file, and distribution of its contents to remote sites for use there is left as an exercise for the reader. X Version 11 Last change: Release 5 5 XSERVER(1) USER COMMANDS XSERVER(1) The server also provides support for SUN-DES-1, using Sun's Secure RPC. It involves encrypting data with the X server's public key. See the _X_s_e_c_u_r_i_t_y manual page for more informa- tion. 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 mechan- ism 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 /_e_t_c/_Xn._h_o_s_t_s, 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 DECnet hostname in double colon format (e.g. hydra::). There should be no leading or trailing spaces on any lines. For example: joesworkstation corporate.company.com star:: bigcpu:: Users can add or remove hosts from this list and enable or disable access control using the _x_h_o_s_t command from the same machine as the server. 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. 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. SIGNALS The X server attaches special meaning to the following sig- nals: _S_I_G_H_U_P This signal causes the server to close all existing connections, free all resources, and restore all defaults. It is sent by the display manager when- ever the main user's main application (usually an _x_t_e_r_m or window manager) exits to force the server to clean up and prepare for the next user. _S_I_G_T_E_R_M This signal causes the server to exit cleanly. _S_I_G_U_S_R_1 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 X Version 11 Last change: Release 5 6 XSERVER(1) USER COMMANDS XSERVER(1) the various connection schemes. _X_d_m uses this feature to recognize when connecting to the server is possible. FONTS Fonts are usually stored as individual files in directories. 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 _f_o_n_t _p_a_t_h. Although most sites will choose to have the X server start up with the appropriate font path (using the -_f_p option mentioned above), it can be overridden using the _x_s_e_t program. The default font path for the X server contains four direc- tories: /_u_s_r/_l_i_b/_X_1_1/_f_o_n_t_s/_m_i_s_c This directory contains many miscellaneous bitmap fonts that are useful on all systems. It contains a family of fixed-width fonts, a family of fixed-width fonts from Dale Schumacher, several Kana fonts from Sony Corporation, two JIS Kanji fonts, two Hangul fonts from Daewoo Electronics, two Hebrew fonts from Joseph Friedman, the standard cursor font, two cur- sor fonts from Digital Equipment Corporation, and cursor and glyph fonts from Sun Microsystems. It also has various font name aliases for the fonts, including fixed and variable. /_u_s_r/_l_i_b/_X_1_1/_f_o_n_t_s/_S_p_e_e_d_o This directory contains outline fonts for Bitstream's Speedo rasterizer. A single font face, in normal, bold, italic, and bold italic, is pro- vided, contributed by Bitstream, Inc. /_u_s_r/_l_i_b/_X_1_1/_f_o_n_t_s/_7_5_d_p_i This directory contains bitmap fonts contributed by Adobe Systems, Inc., Digital Equipment Corporation, Bitstream, Inc., Bigelow and Holmes, and Sun Microsystems, Inc. for 75 dots per inch displays. An integrated selection of sizes, styles, and weights are provided for each family. /_u_s_r/_l_i_b/_X_1_1/_f_o_n_t_s/_1_0_0_d_p_i This directory contains 100 dots per inch versions of some of the fonts in the _7_5_d_p_i directory. Font databases are created by running the _m_k_f_o_n_t_d_i_r program in the directory containing the compiled versions of the fonts (the ._p_c_f files). Whenever fonts are added to a directory, _m_k_f_o_n_t_d_i_r should be rerun so that the server can X Version 11 Last change: Release 5 7 XSERVER(1) USER COMMANDS XSERVER(1) find the new fonts. If _m_k_f_o_n_t_d_i_r is not run, the server will not be able to find any fonts in the directory. DIAGNOSTICS Too numerous to list them all. If run from _i_n_i_t(_8), errors are typically logged in the file /_u_s_r/_a_d_m/_X*_m_s_g_s, FILES /etc/X*.hosts Initial access control list /usr/lib/X11/fonts/100dpi /usr/lib/X11/fonts/misc, /usr/lib/X11/fonts/75dpi, Bitmap font directories /usr/lib/X11/fonts/Speedo Outline font directories /usr/lib/X11/fonts/PEX PEX font directories /usr/lib/X11/rgb.txt Color database /tmp/.X11-unix/X* Unix domain socket /usr/adm/X*msgs Error log file SEE ALSO X(1), bdftopcf(1), mkfontdir(1), fs(1), xauth(1), xdm(1), xhost(1), xinit(1), xset(1), xsetroot(1), xterm(1), Xdec(1), Xibm(1), XmacII(1), Xmips(1), Xqdss(1), Xqvss(1), Xsun(1), Xtek(1), X386(1) _X _W_i_n_d_o_w _S_y_s_t_e_m _P_r_o_t_o_c_o_l, _D_e_f_i_n_i_t_i_o_n _o_f _t_h_e _P_o_r_t_i_n_g _L_a_y_e_r _f_o_r _t_h_e _X _v_1_1 _S_a_m_p_l_e _S_e_r_v_e_r, _S_t_r_a_t_e_g_i_e_s _f_o_r _P_o_r_t_i_n_g _t_h_e _X _v_1_1 _S_a_m_p_l_e _S_e_r_v_e_r, _G_o_d_z_i_l_l_a'_s _G_u_i_d_e _t_o _P_o_r_t_i_n_g _t_h_e _X _V_1_1 _S_a_m_p_l_e _S_e_r_v_e_r BUGS The option syntax is inconsistent with itself and _x_s_e_t(_1). The acceleration option should take a numerator and a denom- inator like the protocol. If _X dies before its clients, new clients won't be able to connect until all existing connections have their TCP TIME_WAIT timers expire. The color database is missing a large number of colors. COPYRIGHT Copyright 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991 Massachusetts Institute of Technology. See _X(_1) for a full statement of rights and permissions. AUTHORS The sample server was originally written by Susan X Version 11 Last change: Release 5 8 XSERVER(1) USER COMMANDS XSERVER(1) Angebranndt, Raymond Drewry, Philip Karlton, and Todd New- man, from Digital Equipment Corporation, with support from a large cast. It has since been extensively rewritten by Keith Packard and Bob Scheifler, from MIT. X Version 11 Last change: Release 5 9