// Copyright 2015 The Chromium OS Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef LIBBRILLO_BRILLO_PROCESS_REAPER_H_
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#define LIBBRILLO_BRILLO_PROCESS_REAPER_H_
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#include <sys/wait.h>
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#include <map>
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#include <base/callback.h>
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#include <base/location.h>
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#include <base/macros.h>
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#include <brillo/asynchronous_signal_handler.h>
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namespace brillo {
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class BRILLO_EXPORT ProcessReaper final {
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public:
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// The callback called when a child exits.
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using ChildCallback = base::Callback<void(const siginfo_t&)>;
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ProcessReaper() = default;
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~ProcessReaper();
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// Register the ProcessReaper using either the provided
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// brillo::AsynchronousSignalHandlerInterface. You can call Unregister() to
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// remove this ProcessReapper or it will be called during shutdown.
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// You can only register this ProcessReaper with one signal handler at a time.
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void Register(AsynchronousSignalHandlerInterface* async_signal_handler);
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// Unregisters the ProcessReaper from the
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// brillo::AsynchronousSignalHandlerInterface passed in Register(). It
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// doesn't do anything if not registered.
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void Unregister();
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// Watch for the child process |pid| to finish and call |callback| when the
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// selected process exits or the process terminates for other reason. The
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// |callback| receives the exit status and exit code of the terminated process
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// as a siginfo_t. See wait(2) for details about siginfo_t.
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bool WatchForChild(const base::Location& from_here,
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pid_t pid,
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const ChildCallback& callback);
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// Stop watching child process |pid|. This is useful in situations
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// where the child process may have been reaped outside of the signal
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// handler, or the caller is no longer interested in being notified about
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// this child process anymore. Returns true if a child was removed from
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// the watchlist.
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bool ForgetChild(pid_t pid);
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private:
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// SIGCHLD handler for the AsynchronousSignalHandler. Always returns false
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// (meaning that the signal handler should not be unregistered).
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bool HandleSIGCHLD(const signalfd_siginfo& sigfd_info);
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struct WatchedProcess {
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base::Location location;
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ChildCallback callback;
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};
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std::map<pid_t, WatchedProcess> watched_processes_;
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// The |async_signal_handler_| is owned by the caller and is |nullptr| when
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// not registered.
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AsynchronousSignalHandlerInterface* async_signal_handler_{nullptr};
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DISALLOW_COPY_AND_ASSIGN(ProcessReaper);
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};
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} // namespace brillo
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#endif // LIBBRILLO_BRILLO_PROCESS_REAPER_H_
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