gdbserver(1) GNU Development Tools gdbserver(1)
gdbserver - Remote Server for the GNU Debugger
tty prog [args...]
gdbserver tty --attach PID
GDBSERVER is a program that allows you to run GDB on a different machine than the one
which is running the program being debugged.
Usage (server (target) side):
First, you need to have a copy of the program you want to debug put onto the target sys-
tem. 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 com-
municate 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.
On some targets, gdbserver can also attach to running programs. This is accomplished via
the --attach argument. The syntax is:
target> gdbserver COMM --attach PID
PID is the process ID of a currently running process. It isn't necessary to point gdb-
server at a binary for the running process.
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 TAR-
GET-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'.
You have to supply the name of the program to debug and the tty to communicate on; the
remote GDB will do everything else. Any remaining arguments will be passed to the program
`gdb' entry in info; Using GDB: A Guide to the GNU Source-Level Debugger, Richard M.
Stallman and Roland H. Pesch, July 1991.
Copyright (c) 1993 Free Software Foundation, Inc.
Permission is granted to make and distribute verbatim copies of this manual provided the
copyright notice and this permission notice are preserved on all copies.
Permission is granted to copy and distribute modified versions of this manual under the
conditions for verbatim copying, provided that the entire resulting derived work is dis-
tributed under the terms of a permission notice identical to this one.
Permission is granted to copy and distribute translations of this manual into another lan-
guage, under the above conditions for modified versions, except that this permission
notice may be included in translations approved by the Free Software Foundation instead of
in the original English.
Cygnus Support 2 November 1993 gdbserver(1)