			README for GDBserver
			  by Stu Grossman

Introduction:

This is GDBserver, a remote server for Un*x-like systems.  It can be used to
control the execution of a program on a target system from a GDB on a different
host.  GDB and GDBserver communicate using the standard remote serial protocol
implemented in remote.c, and various *-stub.c files.  They communicate via
either a serial line or a TCP connection.

Usage (server (target) side):

First, you need to have a copy of the program you want to debug put onto
the target system.  The program can be stripped to save space if needed, as
GDBserver doesn't care about symbols.  All symbol handling is taken care of by
the GDB running on the host system.

To use the server, you log on to the target system, and run the `gdbserver'
program.  You must tell it (a) how to communicate with GDB, (b) the name of
your program, and (c) its arguments.  The general syntax is:

	target> gdbserver COMM PROGRAM [ARGS ...]

For example, using a serial port, you might say:

	target> gdbserver /dev/com1 emacs foo.txt

This tells gdbserver to debug emacs with an argument of foo.txt, and to
communicate with GDB via /dev/com1.  Gdbserver now waits patiently for the
host GDB to communicate with it.

To use a TCP connection, you could say:

	target> gdbserver host:2345 emacs foo.txt

This says pretty much the same thing as the last example, except that we are
going to communicate with the host GDB via TCP.  The `host:2345' argument means
that we are expecting to see a TCP connection from `host' to local TCP port
2345.  (Currently, the `host' part is ignored.)  You can choose any number you
want for the port number as long as it does not conflict with any existing TCP
ports on the target system.  This same port number must be used in the host
GDBs `target remote' command, which will be described shortly.  Note that if
you chose a port number that conflicts with another service, gdbserver will
print an error message and exit.

Usage (host side):

You need an unstripped copy of the target program on your host system, since
GDB needs to examine it's symbol tables and such.  Start up GDB as you normally
would, with the target program as the first argument.  (You may need to use the
--baud option if the serial line is running at anything except 9600 baud.)
Ie: `gdb TARGET-PROG', or `gdb --baud BAUD TARGET-PROG'.  After that, the only
new command you need to know about is `target remote'.  It's argument is either
a device name (usually a serial device, like `/dev/ttyb'), or a HOST:PORT
descriptor.  For example:

	(gdb) target remote /dev/ttyb

communicates with the server via serial line /dev/ttyb, and:

	(gdb) target remote the-target:2345

communicates via a TCP connection to port 2345 on host `the-target', where
you previously started up gdbserver with the same port number.  Note that for
TCP connections, you must start up gdbserver prior to using the `target remote'
command, otherwise you may get an error that looks something like
`Connection refused'.

Building:

Currently, the only target system supported by the server is Lynx.  To build
the server for Lynx, make a new copy of the distribution onto a disk that is
NFS shared with the Lynx system.  Lets say that's in a directory called xyzzy.
Then, follow these steps under the host system:

	1) cd xyzzy/gdb/gdbserver
	2) ../../configure --target i386-none-lynx

When that completes, do the following on the Lynx system:

	3) cd xyzzy/gdb/gdbserver
	4) make CC=gcc

It should build with only a minor complaint about NULL being redefined.  That's
a LynxOS problem, and can be ignored.

It's also possible that you may have a cross-compiler to Lynx.  In that case,
you can skip the stuff about NFS.  You would replace steps 3 & 4 with:

	make CC=lynx-target-compiler...
