binutils-gdb/gdb/gdbsupport/gdb-sigmask.h
Tom Tromey 21987b9c06 Add RAII class for blocking gdb signals
This adds configury support and an RAII class that can be used to
temporarily block signals that are used by gdb.  (This class is not
used in this patch, but it split out for easier review.)

The idea of this patch is that these signals should only be delivered
to the main thread.  So, when creating a background thread, they are
temporarily blocked; the blocked state is inherited by the new thread.

The sigprocmask man page says:

    The use of sigprocmask() is unspecified in a multithreaded
    process; see pthread_sigmask(3).

This patch changes gdb to use pthread_sigmask when appropriate, by
introducing a convenience define.

I've updated gdbserver as well, because I had to touch gdbsupport, and
because the threading patches will make it link against the thread
library.

I chose not to touch the NTO code, because I don't know anything about
that platform and because I cannot test it.

Finally, this modifies an existing spot in the Guile layer to use the
new facility.

gdb/ChangeLog
2019-11-26  Tom Tromey  <tom@tromey.com>

	* gdbsupport/signals-state-save-restore.c (original_signal_mask):
	Remove comment.
	(save_original_signals_state, restore_original_signals_state): Use
	gdb_sigmask.
	* linux-nat.c (block_child_signals, restore_child_signals_mask)
	(_initialize_linux_nat): Use gdb_sigmask.
	* guile/guile.c (_initialize_guile): Use block_signals.
	* Makefile.in (HFILES_NO_SRCDIR): Add gdb-sigmask.h.
	* gdbsupport/gdb-sigmask.h: New file.
	* event-top.c (async_sigtstp_handler): Use gdb_sigmask.
	* cp-support.c (gdb_demangle): Use gdb_sigmask.
	* gdbsupport/common.m4 (GDB_AC_COMMON): Check for
	pthread_sigmask.
	* configure, config.in: Rebuild.
	* gdbsupport/block-signals.h: New file.

gdb/gdbserver/ChangeLog
2019-11-26  Tom Tromey  <tom@tromey.com>

	* remote-utils.c (block_unblock_async_io): Use gdb_sigmask.
	* linux-low.c (linux_wait_for_event_filtered, linux_async): Use
	gdb_sigmask.
	* configure, config.in: Rebuild.

Change-Id: If3f37dc57dd859c226e9e4d79458a0514746e8c6
2019-11-26 14:02:57 -07:00

46 lines
1.3 KiB
C

/* sigprocmask wrapper for gdb
Copyright (C) 2019 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef GDBSUPPORT_GDB_SIGMASK_H
#define GDBSUPPORT_GDB_SIGMASK_H
#include <signal.h>
#ifdef HAVE_SIGPROCMASK
#ifdef HAVE_PTHREAD_SIGMASK
#define gdb_sigmask pthread_sigmask
#else
#define gdb_sigmask sigprocmask
#endif
#else /* HAVE_SIGPROCMASK */
/* Other code checks HAVE_SIGPROCMASK, but if there happened to be a
system that only had pthread_sigmask, we could still use it with
some extra changes. */
#ifdef HAVE_PTHREAD_SIGMASK
#error pthead_sigmask available without sigprocmask - please report
#endif
#endif /* HAVE_SIGPROCMASK */
#endif /* GDBSUPPORT_GDB_SIGMASK_H */