// 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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#include "brillo/process_reaper.h"
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#include <sys/signalfd.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <base/bind.h>
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#include <base/posix/eintr_wrapper.h>
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#include <brillo/asynchronous_signal_handler.h>
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#include <brillo/location_logging.h>
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namespace brillo {
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ProcessReaper::~ProcessReaper() {
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Unregister();
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}
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void ProcessReaper::Register(
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AsynchronousSignalHandlerInterface* async_signal_handler) {
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CHECK(!async_signal_handler_);
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async_signal_handler_ = async_signal_handler;
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async_signal_handler->RegisterHandler(
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SIGCHLD,
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base::Bind(&ProcessReaper::HandleSIGCHLD, base::Unretained(this)));
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}
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void ProcessReaper::Unregister() {
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if (!async_signal_handler_)
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return;
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async_signal_handler_->UnregisterHandler(SIGCHLD);
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async_signal_handler_ = nullptr;
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}
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bool ProcessReaper::WatchForChild(const base::Location& from_here,
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pid_t pid,
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const ChildCallback& callback) {
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if (watched_processes_.find(pid) != watched_processes_.end())
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return false;
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watched_processes_.emplace(pid, WatchedProcess{from_here, callback});
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return true;
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}
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bool ProcessReaper::ForgetChild(pid_t pid) {
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return watched_processes_.erase(pid) != 0;
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}
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bool ProcessReaper::HandleSIGCHLD(
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const struct signalfd_siginfo& /* sigfd_info */) {
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// One SIGCHLD may correspond to multiple terminated children, so ignore
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// sigfd_info and reap any available children.
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while (true) {
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siginfo_t info;
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info.si_pid = 0;
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int rc = HANDLE_EINTR(waitid(P_ALL, 0, &info, WNOHANG | WEXITED));
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if (rc == -1) {
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if (errno != ECHILD) {
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PLOG(ERROR) << "waitid failed";
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}
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break;
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}
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if (info.si_pid == 0) {
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break;
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}
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auto proc = watched_processes_.find(info.si_pid);
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if (proc == watched_processes_.end()) {
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LOG(INFO) << "Untracked process " << info.si_pid
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<< " terminated with status " << info.si_status
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<< " (code = " << info.si_code << ")";
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} else {
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DVLOG_LOC(proc->second.location, 1)
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<< "Process " << info.si_pid << " terminated with status "
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<< info.si_status << " (code = " << info.si_code << ")";
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ChildCallback callback = std::move(proc->second.callback);
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watched_processes_.erase(proc);
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callback.Run(info);
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}
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}
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// Return false to indicate that our handler should not be uninstalled.
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return false;
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}
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} // namespace brillo
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