/usr/include/ola/thread/SignalThread.h is in libola-dev 0.10.5.nojsmin-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* SignalThread.h
* A thread to handle signals.
* Copyright (C) 2013 Simon Newton
*/
#ifndef INCLUDE_OLA_THREAD_SIGNALTHREAD_H_
#define INCLUDE_OLA_THREAD_SIGNALTHREAD_H_
#include <signal.h>
#include <ola/Callback.h>
#include <ola/base/Macro.h>
#include <ola/thread/Thread.h>
#include <map>
namespace ola {
namespace thread {
/**
* Signals and threads don't play nicely together. Consider the following:
* - thread1, acquires mutex M
* - signal triggers
* - thread1 runs the signal handler
* - signal handler attempts to aqcuire mutex M
* - deadlock...
*
* The recommended way to deal with this is to run a separate thread, whose
* sole purpose is to wait for signals. See section 12.8 of APUE.
*
* To avoid this we do the following:
* - mask all signals that we define custom handlers for
* - spawn a thread which uses sigwait() to capture signals
*/
class SignalThread : public ola::thread::Thread {
public:
typedef ola::Callback0<void> SignalHandler;
SignalThread();
~SignalThread();
// This has to be called before Start(). You can't add signal handlers once
// the thread is running.
bool InstallSignalHandler(int signal, SignalHandler *handler);
protected:
void* Run();
private:
typedef std::map<int, SignalHandler*> SignalMap;
SignalMap m_signal_handlers;
bool AddSignals(sigset_t *signals);
bool BlockSignal(int signal);
DISALLOW_COPY_AND_ASSIGN(SignalThread);
};
} // namespace thread
} // namespace ola
#endif // INCLUDE_OLA_THREAD_SIGNALTHREAD_H_
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