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// Copyright 2017 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef SRC_MAIN_TOOLS_PROCESS_WRAPPER_LEGACY_H_
#define SRC_MAIN_TOOLS_PROCESS_WRAPPER_LEGACY_H_
#include <signal.h>
#include <vector>
// The process-wrapper implementation that was used until and including Bazel
// 0.4.5. Waits for the wrapped process to exit and then kills its process
// group. Works on all POSIX operating systems (tested on Linux, macOS,
// FreeBSD, and OpenBSD).
//
// Caveats:
// - Killing just the process group of the spawned child means that daemons or
// other processes spawned by the child may not be killed if they change their
// process group.
// - Does not wait for grandchildren to exit, thus processes spawned by the
// child that could not be killed will linger around in the background.
// - Has a PID reuse race condition, because the kill() to the process group is
// sent after waitpid() was called on the main child.
class LegacyProcessWrapper {
public:
// Run the command specified in the `opt.args` array and kill it after
// `opt.timeout_secs` seconds.
static void RunCommand();
private:
static void SpawnChild();
static void SetupSignalHandlers();
static void WaitForChild();
static void OnAbruptSignal(int sig);
static void OnGracefulSignal(int sig);
static pid_t child_pid;
static volatile sig_atomic_t last_signal;
};
#endif