Alex Deymo | 471776d | 2015-07-21 16:12:27 -0700 | [diff] [blame^] | 1 | // Copyright 2015 The Chromium OS Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #ifndef LIBCHROMEOS_CHROMEOS_PROCESS_REAPER_H_ |
| 6 | #define LIBCHROMEOS_CHROMEOS_PROCESS_REAPER_H_ |
| 7 | |
| 8 | #include <sys/wait.h> |
| 9 | |
| 10 | #include <map> |
| 11 | |
| 12 | #include <base/callback.h> |
| 13 | #include <base/location.h> |
| 14 | #include <base/macros.h> |
| 15 | #include <chromeos/asynchronous_signal_handler.h> |
| 16 | #include <chromeos/daemons/daemon.h> |
| 17 | |
| 18 | namespace chromeos { |
| 19 | |
| 20 | class CHROMEOS_EXPORT ProcessReaper final { |
| 21 | public: |
| 22 | // The callback called when a child exits. |
| 23 | using ChildCallback = base::Callback<void(const siginfo_t&)>; |
| 24 | |
| 25 | ProcessReaper() = default; |
| 26 | ~ProcessReaper(); |
| 27 | |
| 28 | // Register the ProcessReaper using either the provided chromeos::Daemon or |
| 29 | // chromeos::AsynchronousSignalHandler. You can call Unregister() to remove |
| 30 | // this ProcessReapper or it will be called during shutdown. |
| 31 | void RegisterWithAsynchronousSignalHandler( |
| 32 | AsynchronousSignalHandler* async_signal_handler); |
| 33 | void RegisterWithDaemon(Daemon* daemon); |
| 34 | |
| 35 | // Unregisters the ProcessReaper from the chromeos::Daemon or |
| 36 | // chromeos::AsynchronousSignalHandler passed in RegisterWith*(). It doesn't |
| 37 | // do anything if not registered. |
| 38 | void Unregister(); |
| 39 | |
| 40 | // Watch for the child process |pid| to finish and call |callback| when the |
| 41 | // selected process exits or the process terminates for other reason. The |
| 42 | // |callback| receives the exit status and exit code of the terminated process |
| 43 | // as a siginfo_t. See wait(2) for details about siginfo_t. |
| 44 | bool WatchForChild(const tracked_objects::Location& from_here, |
| 45 | pid_t pid, |
| 46 | const ChildCallback& callback); |
| 47 | |
| 48 | private: |
| 49 | // SIGCHLD handler for the AsynchronousSignalHandler. Always returns false |
| 50 | // (meaning that the signal handler should not be unregistered). |
| 51 | bool HandleSIGCHLD(const signalfd_siginfo& sigfd_info); |
| 52 | |
| 53 | struct WatchedProcess { |
| 54 | tracked_objects::Location location; |
| 55 | ChildCallback callback; |
| 56 | }; |
| 57 | std::map<pid_t, WatchedProcess> watched_processes_; |
| 58 | |
| 59 | // Whether the ProcessReaper already registered a signal. |
| 60 | bool registered_{false}; |
| 61 | |
| 62 | // The |async_signal_handler_| and |daemon_| are owned by the caller and only |
| 63 | // one of them is not nullptr. |
| 64 | AsynchronousSignalHandler* async_signal_handler_{nullptr}; |
| 65 | Daemon* daemon_{nullptr}; |
| 66 | |
| 67 | DISALLOW_COPY_AND_ASSIGN(ProcessReaper); |
| 68 | }; |
| 69 | |
| 70 | } // namespace chromeos |
| 71 | |
| 72 | #endif // LIBCHROMEOS_CHROMEOS_PROCESS_REAPER_H_ |