old-cross-binutils/gdb/gdbserver
Pedro Alves 3e74e146f2 Linux: No need to set ptrace event options in fork/clone children.
Oleg Nesterov told me that the Linux kernel copies the parent's ptrace
options to fork/clone children, so there's no need for GDB to do that
manually.

I was actually a bit surprised, since I thought the ptracer had to
always set the ptrace options itself, and GDB is indeed calling
PTRACE_SETOPTIONS for each new fork child, if it'll stay attached.

Looking at the history of that code, I found that is was actually I
who added that set-ptrace-options-in-children bit, back in
http://sourceware.org/ml/gdb-patches/2009-05/msg00656.html.  But,
honestly, I don't recall why I needed that.  I think I may have just
blindly believed it was necessary.

I then looked back at the history of all the PTRACE_SETOPTIONS code we
have, and found that gdb never did copy the ptrace options before my
patch.  But, when gdbserver learnt to use PTRACE_EVENT_CLONE, at
http://sourceware.org/ml/gdb-patches/2007-10/msg00547.html, it was
made to do 'ptrace (PTRACE_SETOPTIONS, new_pid, 0,
PTRACE_O_TRACECLONE)' for all new clones.  Hmmm.  But, GDB itself
never did that, so it can't really ever have been necessary, I
believe, otherwise GDB should have been doing it too.

(GDBserver doesn't support following forks, and so naturally doesn't
do any PTRACE_SETOPTIONS on fork children.)

So this patch removes the -I believe- unnecessary ptrace syscalls.

Tested on x86_64 Fedora 17, native/gdbserver, and on x86_64 RHEL5
native/gdbserver (Linux 2.6.18, I think a ptrace-on-utrace kernel).
No regressions.

gdb/
2013-03-22  Pedro Alves  <palves@redhat.com>

	* linux-nat.c (linux_child_follow_fork): Don't call
	linux_enable_event_reporting.
	(linux_handle_extended_wait): Don't call
	linux_enable_event_reporting.

gdb/gdbserver/
2013-03-22  Pedro Alves  <palves@redhat.com>

	* linux-low.c (handle_extended_wait): Don't call
	linux_enable_event_reporting.
2013-03-22 14:52:26 +00:00
..
.gitignore
acinclude.m4 * Makefile.in (DEPMODE, DEPDIR, depcomp, COMPILE.pre) 2012-12-10 20:16:14 +00:00
aclocal.m4 2012-04-19 Pedro Alves <palves@redhat.com> 2012-04-19 19:34:52 +00:00
ax.c * ada-lang.c (ada_read_renaming_var_value): Pass const 2013-03-12 17:39:45 +00:00
ax.h gdb/gdbserver: 2013-01-18 06:40:58 +00:00
ChangeLog Linux: No need to set ptrace event options in fork/clone children. 2013-03-22 14:52:26 +00:00
config.in Add the gdb remote target operations for branch tracing. 2013-03-11 08:35:11 +00:00
configure Add the gdb remote target operations for branch tracing. 2013-03-11 08:35:11 +00:00
configure.ac Add the gdb remote target operations for branch tracing. 2013-03-11 08:35:11 +00:00
configure.srv Add the gdb remote target operations for branch tracing. 2013-03-11 08:35:11 +00:00
dll.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
event-loop.c gdb/gdbserver 2013-01-25 14:12:02 +00:00
gdb_proc_service.h Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
gdbreplay.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
gdbserver.1 Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
gdbthread.h Add the gdb remote target operations for branch tracing. 2013-03-11 08:35:11 +00:00
hostio-errno.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
hostio.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
i386-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
i386-low.h Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
i387-fp.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
i387-fp.h Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
inferiors.c Add the gdb remote target operations for branch tracing. 2013-03-11 08:35:11 +00:00
linux-aarch64-low.c 2013-02-07 Marcus Shawcroft <marcus.shawcroft@arm.com> 2013-02-07 17:32:29 +00:00
linux-amd64-ipa.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
linux-arm-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
linux-bfin-low.c gdb/gdbserver 2013-02-18 14:54:57 +00:00
linux-cris-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
linux-crisv32-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
linux-i386-ipa.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
linux-ia64-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
linux-low.c Linux: No need to set ptrace event options in fork/clone children. 2013-03-22 14:52:26 +00:00
linux-low.h Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
linux-m32r-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
linux-m68k-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
linux-mips-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
linux-ppc-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
linux-s390-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
linux-sh-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
linux-sparc-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
linux-tic6x-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
linux-tile-low.c gdb/ 2013-02-27 14:58:18 +00:00
linux-x86-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
linux-xtensa-low.c Consistent use of (C) after "Copyright". 2013-02-12 19:03:57 +00:00
lynx-i386-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
lynx-low.c Simplifly ptrace_request_to_str's implementation... 2013-01-07 11:43:42 +00:00
lynx-low.h Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
lynx-ppc-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
Makefile.in 2013-03-15 Tony Theodore <tonyt@logyst.com> 2013-03-15 17:30:27 +00:00
mem-break.c gdb/gdbserver: 2013-01-18 06:40:58 +00:00
mem-break.h Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
notif.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
notif.h Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
nto-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
nto-low.h Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
nto-x86-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
proc-service.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
proc-service.list Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
README
regcache.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
regcache.h Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
remote-utils.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
server.c Add the gdb remote target operations for branch tracing. 2013-03-11 08:35:11 +00:00
server.h gdb/gdbserver 2013-01-25 14:12:02 +00:00
spu-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
target.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
target.h Add the gdb remote target operations for branch tracing. 2013-03-11 08:35:11 +00:00
terminal.h Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
thread-db.c From: Sanimir Agovic <sanimir.agovic@intel.com> 2013-02-12 15:03:12 +00:00
tracepoint.c 2013-03-14 Sergio Durigan Junior <sergiodj@redhat.com> 2013-03-14 11:40:08 +00:00
utils.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
win32-arm-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
win32-i386-low.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
win32-low.c * win32-low.c: Throughout, fix format strings and casts of 2013-02-28 09:09:02 +00:00
win32-low.h Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
wincecompat.c Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
wincecompat.h Update years in copyright notice for the GDB files. 2013-01-01 06:33:28 +00:00
xtensa-xtregs.c Consistent use of (C) after "Copyright". 2013-02-12 19:03:57 +00:00

		   README for GDBserver & GDBreplay
		    by Stu Grossman and Fred Fish

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.

For more information about GDBserver, see the GDB manual.

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.

On some targets, GDBserver can also attach to running programs.  This is
accomplished via the --attach argument.  The syntax is:

	target> gdbserver --attach COMM PID

PID is the process ID of a currently running process.  It isn't necessary
to point GDBserver 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 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 GDBserver:

The supported targets as of November 2006 are:
	arm-*-linux*
	bfin-*-uclinux
	bfin-*-linux-uclibc
	crisv32-*-linux*
	cris-*-linux*
	i[34567]86-*-cygwin*
	i[34567]86-*-linux*
	i[34567]86-*-mingw*
	ia64-*-linux*
	m32r*-*-linux*
	m68*-*-linux*
	m68*-*-uclinux*
	mips*64*-*-linux*
	mips*-*-linux*
	powerpc[64]-*-linux*
	s390[x]-*-linux*
	sh-*-linux*
	spu*-*-*
	x86_64-*-linux*

Configuring GDBserver you should specify the same machine for host and
target (which are the machine that GDBserver is going to run on.  This
is not the same as the machine that GDB is going to run on; building
GDBserver automatically as part of building a whole tree of tools does
not currently work if cross-compilation is involved (we don't get the
right CC in the Makefile, to start with)).

Building GDBserver for your target is very straightforward.  If you build
GDB natively on a target which GDBserver supports, it will be built
automatically when you build GDB.  You can also build just GDBserver:

	% mkdir obj
	% cd obj
	% path-to-gdbserver-sources/configure
	% make

If you prefer to cross-compile to your target, then you can also build
GDBserver that way.  In a Bourne shell, for example:

	% export CC=your-cross-compiler
	% path-to-gdbserver-sources/configure your-target-name
	% make

Using GDBreplay:

A special hacked down version of GDBserver can be used to replay remote
debug log files created by GDB.  Before using the GDB "target" command to
initiate a remote debug session, use "set remotelogfile <filename>" to tell
GDB that you want to make a recording of the serial or tcp session.  Note
that when replaying the session, GDB communicates with GDBreplay via tcp,
regardless of whether the original session was via a serial link or tcp.

Once you are done with the remote debug session, start GDBreplay and
tell it the name of the log file and the host and port number that GDB
should connect to (typically the same as the host running GDB):

	$ gdbreplay logfile host:port

Then start GDB (preferably in a different screen or window) and use the
"target" command to connect to GDBreplay:

	(gdb) target remote host:port

Repeat the same sequence of user commands to GDB that you gave in the
original debug session.  GDB should not be able to tell that it is talking
to GDBreplay rather than a real target, all other things being equal.  Note
that GDBreplay echos the command lines to stderr, as well as the contents of
the packets it sends and receives.  The last command echoed by GDBreplay is
the next command that needs to be typed to GDB to continue the session in
sync with the original session.