GNUSERV(1)						      General Commands Manual							GNUSERV(1)

NAME

       gnuserv, gnuclient - Server and Clients for XEmacs

SYNOPSIS

       gnuclient  [-nw] [-display display] [-q] [-v] [-l library] [-batch] [-f function] [-eval form] [-h hostname] [-p port] [-r remote-pathname]
       [[+line] file] ...
       gnudoit [-q] form
       gnuserv
       gnuattach Removed as of gnuserv 3.x

DESCRIPTION

       gnuserv is a server program run as a subprocess of XEmacs to handle all incoming and outgoing requests from gnuclient. It  is  not  usually
       invoked directly, but is started from XEmacs by loading the gnuserv package and evaluating the Lisp form (gnuserv-start).

       gnuclient allows the user to request a running XEmacs process to edit the named files or directories and/or evaluate lisp forms.  Depending
       on your environment, TTY, X, GTK, or MS Windows frames, as well as batch (frameless) execution of Lisp may be available.  One  typical  use
       for this is with a dialup connection to a machine on which an XEmacs process is currently running.

       gnudoit	is  a  shell  script  frontend	to  ``gnuclient  -batch -eval form''.  Its use is deprecated. Try to get used to calling gnuclient
       directly.

       gnuattach no longer exists. Its functionality has been replaced by gnuclient -nw.

OPTIONS

       gnuclient supports as many of the command line options of Emacs as make sense in this context. In addition it adds a few of its own.
       For backward compatibility, ``long'' options (.e., with doubled hyphen) may be specified using a single hyphen instead of  a  doubled  one.
       Similarly, the ``-nw'' option is a historical artifact: a multiletter option with no double-hyphen version.

       -nw     This  option  makes  gnuclient  act  as	a frontend such that XEmacs can attach to the current TTY. XEmacs will then open a new TTY
	       frame.  The effect is similar to having started a new XEmacs on this TTY with the ``-nw'' option. It currently only works if XEmacs
	       is running on the same machine as gnuclient. This is the default if the `DISPLAY' environment variable is not set.

       --display display, -display display
	       If  this  option  is given or the `DISPLAY' environment variable is set then gnuclient will tell XEmacs to edit files in a frame on
	       the specified X device.

       -q      This option informs gnuclient to exit once connection has been made with the XEmacs process.  Normally gnuclient waits until all of
	       the  files  on  the  command line have been finished with (their buffers killed) by the XEmacs process, and all the forms have been
	       evaluated.  Note that this is different from XEmacs itself, where this option means to inhibit loading of the user init file.

       -v      When this option is specified gnuclient will request for the specified files to be viewed instead of edited.

       -l library
	       Tell Emacs to load the specified library.

       -batch  Tell Emacs not to open any frames. Just load libraries and evaluate lisp code.  If no files to execute, functions to call or  forms
	       to eval are given using the -l, -f, or -eval options, then forms to eval are read from STDIN.

       -f function,
	       Make Emacs execute the lisp function.

       --eval form, -eval form
	       Make Emacs execute the Lisp form.

       -h hostname
	       Used  only  with Internet-domain sockets, this option specifies the host machine which should be running gnuserv. If this option is
	       not specified then the value of the environment variable GNU_HOST is used if set. If no hostname is  specified,	and  the  GNU_HOST
	       variable  is  not set, an Internet connection will not be attempted. N.B.: gnuserv does NOT allow Internet connections unless XAUTH
	       authentication is used or the GNU_SECURE variable has been specified and points at a file listing all trusted hosts. (See  SECURITY
	       below.)

	       An Internet address (``dotted-quad'') may be specified instead of a hostname.  IPv6 support is not robust.

	       A  hostname  of unix can be used to specify that the connection to the server should use a Unix-domain socket (if supported) rather
	       than an Internet-domain socket.

       -p port Used only with Internet-domain sockets, this option specifies the service port used to communicate between server and clients.	If
	       this  option  is  not  specified,  then	the value of the environment variable GNU_PORT is used, if set, otherwise a service called
	       ``gnuserv'' is looked up in the services database.  Finally, if no other value can be found for the port, then a  default  port	is
	       used which is usually 21490 + uid.
	       Note  that  since  gnuserv doesn't allow command-line options, the port for it will have to be specified via one of the alternative
	       methods.

       -r pathname
	       Used only with Internet-domain sockets, the pathname argument may be needed to inform XEmacs how to reach the root directory  of  a
	       remote  machine.   gnuclient prepends this string to each path argument given.  For example, if you were trying to edit a file on a
	       client machine called otter, whose root directory was accessible from the server machine via the path /net/otter, then  this  argu-
	       ment  should be set to '/net/otter'.  If this option is omitted, then the value is taken from the environment variable GNU_NODE, if
	       set, or the empty string otherwise.

       [+n] file
	       This is the path of the file to be edited.  If the file is a directory, then the directory browsers dired  or  monkey  are  usually
	       invoked instead.  The cursor is put at line number 'n' if specified.

SETUP

       gnuserv	is included with recent versions of XEmacs; no installation is required.  The server must be started before clients may attempt to
       connect.  Start the server by evaluating the Lisp form (gnuserv-start), or interactively by typing `M-x gnuserv-start'.

CONFIGURATION

       The behavior of this suite of programs can be customized to a large extent.  Type `M-x customize-group RET gnuserv RET'.   More	documenta-
       tion can be found in the file `gnuserv.el'

EXAMPLE

	   gnuclient -q -f mh-smail
	   gnuclient -h cuckoo -r /ange@otter: /tmp/*
	   gnuclient -nw ../src/listproc.c

       More examples and sample wrapper scripts are provided in the etc/gnuserv directory of the XEmacs installation.

SYSV IPC

       SysV  IPC  is a build-time option, enabled by defining the symbol SYSV_IPC at the top of gnuserv.h.  It is used to communicate between gnu-
       client and gnuserv.  It is incompatible with both Unix-domain and Internet-domain socket communication as described below.  A  file  called
       /tmp/gsrv??? is created as a key for the message queue, and if removed will cause the communication between server and client to fail until
       the server is restarted.

UNIX-DOMAIN SOCKETS
       Unix-domain sockets are a build-time option, enabled by defining the symbol UNIX_DOMAIN_SOCKETS at the top  of  gnuserv.h.   A  Unix-domain
       socket  is  used  to  communicate between gnuclient and gnuserv.  A file called /tmp/gsrvdir????/gsrv is created for communication.  If the
       symbol USE_TMPDIR is set at the top of gnuserv.h, $TMPDIR, when set, is used instead of /tmp.  If that file is deleted, or TMPDIR has  dif-
       ferent values for the server and the client, communication between server and client will fail.	Only the user running gnuserv will be able
       to connect to the socket.

INTERNET-DOMAIN SOCKETS
       Internet-domain sockets are a build-time option, enabled by defining the symbol INTERNET_DOMAIN_SOCKETS at the top of gnuserv.h.  Internet-
       domain sockets are used to communicate between gnuclient and gnuserv.  Both Internet-domain and Unix-domain sockets can be used at the same
       time.  If a hostname is specified via -h or via the GNU_HOST environment variable, gnuclient establish connections using an Internet domain
       socket. If not, a local connection is attempted via either a Unix-domain socket or SYSV IPC.

SECURITY

       Using  Internet-domain sockets, a more robust form of security is needed that wasn't necessary with either Unix-domain sockets or SysV IPC.
       Currently, two authentication protocols are supported to provide this: MIT-MAGIC-COOKIE-1 (based on the X11 xauth(1) program) and a  simple
       host-based  access  control  mechanism,	hereafter  called  GNUSERV-1.  The GNUSERV-1 protocol is always available.  Support for MIT-MAGIC-
       COOKIE-1 is enabled (by defining AUTH_MAGIC_COOKIE at the top of gnuserv.h.

       gnuserv, using GNUSERV-1, performs a limited form of access control at the machine level. By default no Internet-domain socket  is  opened.
       If the variable GNU_SECURE can be found in gnuserv's environment, and it names a readable filename, then this file is opened and assumed to
       be a list of hosts, one per line, from which the server will allow requests. Connections from any other host will  be  rejected.  Even  the
       machine	on  which gnuserv is running is not permitted to make connections via the Internet socket unless its hostname is explicitly speci-
       fied in this file.  Note that a host may be either a numeric IP address or a hostname, and that any user on an approved host may connect to
       your  gnuserv  and execute arbitrary Lisp (e.g., delete all your files).  If this file contains a lot of hostnames then the server may take
       quite a long time to start up.

       When the MIT-MAGIC-COOKIE-1 protocol is enabled, an Internet socket is opened by default. gnuserv will accept a connection from	any  host,
       and will wait for a "magic cookie" (essentially, a password) to be presented by the client. If the client doesn't present the cookie, or if
       the cookie is wrong, the authentication of the client is considered to have failed. At this point. gnuserv falls back to the GNUSERV-1 pro-
       tocol; If the client is calling from a host listed in the GNU_SECURE file, the connection will be accepted, otherwise it will be rejected.

       Using MIT-MAGIC-COOKIE-1 authentication
	   When  the gnuserv server is started, it looks for a cookie defined for display 999 on the machine where it is running. If the cookie is
	   found, it will be stored for use as the authentication cookie. These cookies are defined in an authorization file (usually  ~/.Xauthor-
	   ity)  that  is  manipulated	by the X11 xauth(1) program. For example, a machine "kali" which runs an emacs that invokes gnuserv should
	   respond as follows (at the shell prompt) when set up correctly.

	       kali% xauth list
	       GS65.SP.CS.CMU.EDU:0  MIT-MAGIC-COOKIE-1  11223344
	       KALI.FTM.CS.CMU.EDU:999	MIT-MAGIC-COOKIE-1  1234

	   In the above case, the authorization file defines two cookies. The second one, defined for screen 999 on the server	machine,  is  used
	   for gnuserv authentication.

	   On the client machine's side, the authorization file must contain an identical line, specifying the server's cookie. In other words, on
	   a machine "foobar" which wishes to connect to "kali,"  the `xauth list' output should contain the line:

	       KALI.FTM.CS.CMU.EDU:999	MIT-MAGIC-COOKIE-1  1234

	   For more information on authorization files, take a look at the xauth(1X11) man page, or invoke xauth interactively (without any  argu-
	   ments)  and	type "help" at the prompt. Remember that case in the name of the authorization protocol (i.e.`MIT-MAGIC-COOKIE-1') is sig-
	   nificant!

ENVIRONMENT

       DISPLAY Default X (or GTK) device for display of edit frame.

FILES

       /tmp/gsrv???
	       (SYSV_IPC only)

       /tmp/gsrvdir???/gsrv
	       (unix domain sockets only)

       ~/.xemacs/init.el
	       XEmacs customization file, see xemacs(1).

SEE ALSO

       xauth(1X11), Xsecurity(1X11), gnuserv.el

BUGS

       NULs occurring in result strings don't get passed back to gnudoit properly.

AUTHOR.
       Andy Norman (ange@hplb.hpl.hp.com), based heavily upon etc/emacsclient.c, etc/server.c and lisp/server.el from the GNU Emacs 18.52  distri-
       bution.	 Various  modifications  from  Bob Weiner (weiner@mot.com), Darrell Kindred (dkindred@cmu.edu), Arup Mukherjee (arup@cmu.edu), Ben
       Wing (ben@xemacs.org) and Hrvoje Niksic (hniksic@xemacs.org).

4th Berkeley Distribution														GNUSERV(1)