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

       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,  it can be an X frame or a TTY frame.  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.

       gnuserv	is  the  server  program  that	is  set  running by XEmacs to handle all incoming and outgoing requests. It is not usually invoked
       directly, but is started from XEmacs by loading the gnuserv package and evaluating the Lisp form (gnuserv-start).

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 Its functionality has been replaced by gnuclient -nw.

OPTIONS

       gnuclient supports as much of the command line options of Emacs as makes sense in this context. In addition it adds a few of its own.
       Options with long names can also be specified using a double hyphen instead of a single one.

       -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.

       -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
	       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.)

	       Note that an internet address may be specified instead of a hostname which can speed up connections to the server by quite  a  bit,
	       especially if the client machine is running YP.

	       Note also that a hostname of unix can be used to specify that the connection to the server should use a Unix-domain socket (if sup-
	       ported) 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 packaged standardly with recent versions of XEmacs.	Therefore, you should be able to start the server simply by evaluating the
       XEmacs Lisp form (gnuserv-start), or equivalently by typing `M-x gnuserv-start'.

CONFIGURATION

       The behavior of this suite of program is mostly controlled on the lisp side in Emacs and its behavior can be customized to a large  extent.
       Type `M-x customize-group RET gnuserv RET' for easy access. More documentation 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 Emacs installation.

SYSV IPC

       SysV IPC is used to communicate between gnuclient and gnuserv if the symbol SYSV_IPC is defined at the top of gnuserv.h. This is incompati-
       ble 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
       A  Unix-domain  socket  is  used  to  communicate  between gnuclient and gnuserv if the symbol UNIX_DOMAIN_SOCKETS is defined at the top of
       gnuserv.h.  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 different values for the server and the client, commu-
       nication 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 used to communicate between gnuclient and gnuserv if the symbol INTERNET_DOMAIN_SOCKETS is defined at  the  top
       of  gnuserv.h.  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, whereas support for MIT-MAGIC-
       COOKIE-1 may or may not have been enabled (via a #define at the top of gnuserv.h) at compile-time.

       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 elisp (e.g., delete all your files).  If this file contains a lot of hostnames then the server may take
       quite a 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 device to put edit frame.

FILES

       /tmp/gsrv???
	       (SYSV_IPC only)

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

       ~/.emacs
	       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)