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// Copyright 2015 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef LIBCHROMEOS_BRILLO_ASYNCHRONOUS_SIGNAL_HANDLER_INTERFACE_H_
#define LIBCHROMEOS_BRILLO_ASYNCHRONOUS_SIGNAL_HANDLER_INTERFACE_H_
#include <sys/signalfd.h>
#include <base/callback.h>
#include <brillo/brillo_export.h>
namespace brillo {
// Sets up signal handlers for registered signals, and converts signal receipt
// into a write on a pipe. Watches that pipe for data and, when some appears,
// execute the associated callback.
class BRILLO_EXPORT AsynchronousSignalHandlerInterface {
public:
virtual ~AsynchronousSignalHandlerInterface() = default;
// The callback called when a signal is received.
using SignalHandler = base::Callback<bool(const struct signalfd_siginfo&)>;
// Register a new handler for the given |signal|, replacing any previously
// registered handler. |callback| will be called on the thread the
// |AsynchronousSignalHandlerInterface| implementation is bound to when a
// signal is received. The received |signalfd_siginfo| will be passed to
// |callback|. |callback| must returns |true| if the signal handler must be
// unregistered, and |false| otherwise. Due to an implementation detail, you
// cannot set any sigaction flags you might be accustomed to using. This might
// matter if you hoped to use SA_NOCLDSTOP to avoid getting a SIGCHLD when a
// child process receives a SIGSTOP.
virtual void RegisterHandler(int signal, const SignalHandler& callback) = 0;
// Unregister a previously registered handler for the given |signal|.
virtual void UnregisterHandler(int signal) = 0;
};
} // namespace brillo
#endif // LIBCHROMEOS_BRILLO_ASYNCHRONOUS_SIGNAL_HANDLER_INTERFACE_H_