Path: utzoo!attcan!uunet!husc6!yale!cmcl2!esquire!yost
From: yost@DPW.COM (David A. Yost)
Newsgroups: comp.windows.x
Subject: Re: I'm looking for code to invoke a slave xterm
Message-ID: <2712@esquire.dpw.com>
Date: 27 Sep 90 14:45:10 GMT
References: <2247@esquire.UUCP>
Organization: DP&W, New York, NY
Lines: 74

In article <2247@esquire.UUCP> I wrote:
>I'd like to fork and exec an xterm that has no shell
>running in it and whose stdin and stdout are hooked up
>to two file descriptors in my process.  Anyone done this?

Here's a way to do it:

   xterm -e sockio -il xtermsocket &

This runs sockio in the xterm window instead of a
shell.  The -i option tells sockio to run in interactive
(bidirectional copy) mode, and the l option tells it to
listen and accept a connection on "xtermsocket", which
is a unix domain socket.  Then to talk to the xterm
window, you do this:

   sockio -i xtermsocket

I will post sockio to comp.unix.sources sometime soon.
Here's what it does:

Usage: sockio <options> [ -l [ -c ] ] <name>
or:    sockio <options> -d inet <socket> [ <host> ]
or:    sockio <options> -d inet -l [ -c ] [ <socket> ]

Options: [ -k ] [ -i ] or [ -r [ -a ] ] [ -v ] [ -s <size> ]

Copies between unix or inet stream socket
and standard input and/or output in one of three modes:
By default, copies from stdin to socket (write mode).
-r Read mode: copies from socket to stdout.
-i Interactive mode: copies from socket to stdout and from stdin to socket.
-l Sockio listens on the socket and accepts a connection.  If unix
   domain, removes the socket file when it exits or is killed.
-c Sockio continually listens for and accepts new connections.
   Otherwise, when the other end closes the connection, sockio exits.
-k When the -l option is not given, by default sockio expects the socket
   to already exist, and exits with status 1 if it doesn't exist.
   If the -k option is given, it keeps trying to connect.
-s <size>
   How many bytes or lines to copy.  A numeric size is a number of bytes,
   a number followed by an 'l' is a number of lines.
-a Used only with -r, the -a option tells sockio to read all it can
   (up to the given size, if any) until the socket becomes empty, then exit.
-v Verbosity: notify on connects and accepts.
-d inet
   Additional arguments:
   A <host> name or numeric address in dot notation, default is this host.
   A <socket> argument which can be a number or a service name.
	In the -l case, <socket> can be unspecified, in which case a socket
	number is assigned by the system, and the number reported to stderr.

If no -d option is given, then the <name> given is taken
as a filename representing a unix domain socket.

Examples:
   sockio -rlc logs | tee logfile &
   date | sockio logs
   date | sockio logs
or:
   awk < /dev/null 'BEGIN { for (;;) print ++n }' | sockio -lc -s 1l numbers &
   sockio -r numbers
   sockio -r numbers
or:
   xterm -e sockio -il xtermsocket &
   sockio -i xtermsocket

Bug: if the writer is invoked with -l and -c, output data stranded in the
socket when the reader closes the socket is lost.

 --dave yost
   yost@dpw.com or uunet!esquire!yost
   Please don't use other mangled forms you may see
   in the From, Reply-To, or CC fields above.