| // Copyright (c) 2009 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "chrome/common/process_watcher.h" |
| |
| #include <errno.h> |
| #include <signal.h> |
| #include <sys/types.h> |
| #include <sys/wait.h> |
| |
| #include "base/eintr_wrapper.h" |
| #include "base/platform_thread.h" |
| |
| // Return true if the given child is dead. This will also reap the process. |
| // Doesn't block. |
| static bool IsChildDead(pid_t child) { |
| const pid_t result = HANDLE_EINTR(waitpid(child, NULL, WNOHANG)); |
| if (result == -1) { |
| PLOG(ERROR) << "waitpid(" << child << ")"; |
| NOTREACHED(); |
| } else if (result > 0) { |
| // The child has died. |
| return true; |
| } |
| |
| return false; |
| } |
| |
| // A thread class which waits for the given child to exit and reaps it. |
| // If the child doesn't exit within a couple of seconds, kill it. |
| class BackgroundReaper : public PlatformThread::Delegate { |
| public: |
| explicit BackgroundReaper(pid_t child, unsigned timeout) |
| : child_(child), |
| timeout_(timeout) { |
| } |
| |
| void ThreadMain() { |
| WaitForChildToDie(); |
| delete this; |
| } |
| |
| void WaitForChildToDie() { |
| // Wait forever case. |
| if (timeout_ == 0) { |
| pid_t r = HANDLE_EINTR(waitpid(child_, NULL, 0)); |
| if (r != child_) { |
| LOG(ERROR) << "While waiting for " << child_ |
| << " to terminate, we got the following result: " << r; |
| } |
| return; |
| } |
| |
| // There's no good way to wait for a specific child to exit in a timed |
| // fashion. (No kqueue on Linux), so we just loop and sleep. |
| |
| // Wait for 2 * timeout_ 500 milliseconds intervals. |
| for (unsigned i = 0; i < 2 * timeout_; ++i) { |
| PlatformThread::Sleep(500); // 0.5 seconds |
| if (IsChildDead(child_)) |
| return; |
| } |
| |
| if (kill(child_, SIGKILL) == 0) { |
| // SIGKILL is uncatchable. Since the signal was delivered, we can |
| // just wait for the process to die now in a blocking manner. |
| HANDLE_EINTR(waitpid(child_, NULL, 0)); |
| } else { |
| LOG(ERROR) << "While waiting for " << child_ << " to terminate we" |
| << " failed to deliver a SIGKILL signal (" << errno << ")."; |
| } |
| } |
| |
| private: |
| const pid_t child_; |
| // Number of seconds to wait, if 0 then wait forever and do not attempt to |
| // kill |child_|. |
| const unsigned timeout_; |
| |
| DISALLOW_COPY_AND_ASSIGN(BackgroundReaper); |
| }; |
| |
| // static |
| void ProcessWatcher::EnsureProcessTerminated(base::ProcessHandle process) { |
| // If the child is already dead, then there's nothing to do |
| if (IsChildDead(process)) |
| return; |
| |
| const unsigned timeout = 2; // seconds |
| BackgroundReaper* reaper = new BackgroundReaper(process, timeout); |
| PlatformThread::CreateNonJoinable(0, reaper); |
| } |
| |
| // static |
| void ProcessWatcher::EnsureProcessGetsReaped(base::ProcessHandle process) { |
| // If the child is already dead, then there's nothing to do |
| if (IsChildDead(process)) |
| return; |
| |
| BackgroundReaper* reaper = new BackgroundReaper(process, 0); |
| PlatformThread::CreateNonJoinable(0, reaper); |
| } |