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/* RAII class to install a separate handler for a given signal
Copyright (C) 2024 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 SCOPED_SIGNAL_HANDLER_H
#define SCOPED_SIGNAL_HANDLER_H
#include <signal.h>
#undef HAVE_SIGACTION
/* RAII class to set a signal handler for a scope, that will take care of
unsetting the handler when the scope is left.
This class will try to use sigaction whenever available, following the
recommendation on the man page for signal, and only fallback to signal
if necessary. */
template <int SIG>
class scoped_signal_handler
{
public:
scoped_signal_handler (sighandler_t handler)
{
#if defined (HAVE_SIGACTION)
struct sigaction act;
act.sa_handler = handler;
sigemptyset (&act.sa_mask);
act.sa_flags = 0;
sigaction (SIG, &act, &m_prev_handler);
#else
/* The return of the function call is the previous signal handler, or
SIG_ERR if the function doesn't succeed. */
m_prev_handler = signal (SIG, handler);
/* According to the GNU libc manual, the only way signal fails is if
the signum given is invalid, so we should be safe to assert. */
gdb_assert (m_prev_handler != SIG_ERR);
#endif
}
~scoped_signal_handler ()
{
#if defined (HAVE_SIGACTION)
sigaction (SIG, &m_prev_handler, nullptr);
#else
signal (SIG, m_prev_handler);
#endif
}
DISABLE_COPY_AND_ASSIGN (scoped_signal_handler);
private:
#if defined (HAVE_SIGACTION)
struct sigaction m_prev_handler;
#else
sighandler_t m_prev_handler;
#endif
};
#endif /* SCOPED_SIGNAL_HANDLER_H */
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