binutils-gdb/gdb/common/signals-state-save-restore.h

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/* Copyright (C) 2016-2017 Free Software Foundation, Inc.
Fix PR gdb/18653: gdb disturbs inferior's inherited signal dispositions gdb's (or gdbserver's) own signal handling should not interfere with the signal dispositions their spawned children inherit. However, it currently does. For example, some paths in gdb cause SIGPIPE to be set to SIG_IGN, and as consequence, the child starts with SIGPIPE to set to SIG_IGN too, even though gdb was started with SIGPIPE set to SIG_DFL. This is because the exec family of functions does not reset the signal disposition of signals that are set to SIG_IGN: http://pubs.opengroup.org/onlinepubs/7908799/xsh/execve.html Signals set to the default action (SIG_DFL) in the calling process image are set to the default action in the new process image. Signals set to be ignored (SIG_IGN) by the calling process image are set to be ignored by the new process image. Signals set to be caught by the calling process image are set to the default action in the new process image (see <signal.h>). And neither does it reset signal masks or flags. In order to be transparent, when spawning new child processes to debug (with "run", etc.), reset signal actions and mask back to what was originally inherited from gdb/gdbserver's parent, just before execing the target program to debug. gdb/ChangeLog: 2016-08-09 Pedro Alves <palves@redhat.com> PR gdb/18653 * Makefile.in (SFILES): Add common/signals-state-save-restore.c. (HFILES_NO_SRCDIR): Add common/signals-state-save-restore.h. (COMMON_OBS): Add signals-state-save-restore.o. (signals-state-save-restore.o): New rule. * configure: Regenerate. * fork-child.c: Include "signals-state-save-restore.h". (fork_inferior): Call restore_original_signals_state. * main.c: Include "signals-state-save-restore.h". (captured_main): Call save_original_signals_state. * common/common.m4: Add sigaction to AC_CHECK_FUNCS checks. * common/signals-state-save-restore.c: New file. * common/signals-state-save-restore.h: New file. gdb/gdbserver/ChangeLog: 2016-08-09 Pedro Alves <palves@redhat.com> PR gdb/18653 * Makefile.in (OBS): Add signals-state-save-restore.o. (signals-state-save-restore.o): New rule. * config.in: Regenerate. * configure: Regenerate. * linux-low.c: Include "signals-state-save-restore.h". (linux_create_inferior): Call restore_original_signals_state. * server.c: Include "dispositions-save-restore.h". (captured_main): Call save_original_signals_state. gdb/testsuite/ChangeLog: 2016-08-09 Pedro Alves <palves@redhat.com> PR gdb/18653 * gdb.base/signals-state-child.c: New file. * gdb.base/signals-state-child.exp: New file. * gdb.gdb/selftest.exp (do_steps_and_nexts): Add new pattern.
2016-08-09 21:16:20 +02:00
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 COMMON_SIGNALS_STATE_SAVE_RESTORE_H
#define COMMON_SIGNALS_STATE_SAVE_RESTORE_H
/* Save/restore the signal actions of all signals, and the signal
mask.
Since the exec family of functions does not reset the signal
disposition of signals set to SIG_IGN, nor does it reset the signal
mask, in order to be transparent, when spawning new child processes
to debug (with "run", etc.), we must reset signal actions and mask
back to what was originally inherited from gdb/gdbserver's parent,
just before execing the target program to debug. */
/* Save the signal state of all signals. */
extern void save_original_signals_state (void);
/* Restore the signal state of all signals. */
extern void restore_original_signals_state (void);
#endif /* COMMON_SIGNALS_STATE_SAVE_RESTORE_H */