// Copyright 2015 The Crashpad Authors
//
// 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 CRASHPAD_TEST_WIN_WIN_CHILD_PROCESS_H_
#define CRASHPAD_TEST_WIN_WIN_CHILD_PROCESS_H_
#include <memory>
#include "util/file/file_io.h"
#include "util/win/scoped_handle.h"
namespace crashpad {
namespace test {
//! \brief Facilitates the launching of child processes from unit tests.
class WinChildProcess {
public:
//! \brief Groups handles used to communicate with, observe, and manage a
//! child process.
struct Handles {
//! \brief A handle to read from an anonymous pipe shared with the child
//! process.
ScopedFileHANDLE read;
//! \brief A handle to write to an anonymous pipe shared with the child
//! process.
ScopedFileHANDLE write;
//! \brief A handle to the child process.
ScopedKernelHANDLE process;
};
WinChildProcess();
WinChildProcess(const WinChildProcess&) = delete;
WinChildProcess& operator=(const WinChildProcess&) = delete;
virtual ~WinChildProcess() {}
//! \brief Returns true if the current process is a child process.
static bool IsChildProcess();
//! \brief Runs the child process defined by T if the current process is a
//! child process; does not return in that case. Otherwise, returns.
template <class T>
static void EntryPoint() {
if (IsChildProcess()) {
// The static_cast here will cause a compiler failure if T is not a
// subclass of WinChildProcess. It's the constructor of WinChildProcess
// that performs the pipe handshake with the parent process (without which
// we would have a hang).
T child_process;
int result = static_cast<WinChildProcess*>(&child_process)->Run();
exit(result);
}
}
//! \brief Launches a child process and returns the Handles for that process.
//! The process is guaranteed to be executing by the time this method
//! returns. Returns `nullptr` and logs a Google Test failure in case of
//! failure.
static std::unique_ptr<Handles> Launch();
protected:
//! \brief Returns a handle to read from an anonymous pipe shared with the
//! parent process.
//!
//! It is an error to call this after CloseReadPipe() has been called.
//!
//! \return The read pipe's file handle.
FileHandle ReadPipeHandle() const;
//! \brief Returns a handle to write to an anonymous pipe shared with the
//! parent process.
//!
//! It is an error to call this after CloseWritePipe() has been called.
//!
//! \return The write pipe's file handle.
FileHandle WritePipeHandle() const;
//! \brief Closes the read pipe.
//!
//! ReadPipeHandle() must not be called after this.
void CloseReadPipe();
//! \brief Closes the write pipe.
//!
//! An attempt to read from the read pipe in the parent process will indicate
//! end-of-file. WritePipeHandle() must not be called after this.
void CloseWritePipe();
private:
//! \brief The subclass-provided child routine.
//!
//! Subclasses must implement this method to define how the child operates.
//! Subclasses may exit with a failure status by using `LOG(FATAL)`,
//! `abort()`, or similar. They may also exit by returning their exit code
//! from this method. It is up to the client to observe and interpret the
//! child's exit code.
//!
//! \return The child process exit code.
virtual int Run() = 0;
ScopedFileHANDLE pipe_read_;
ScopedFileHANDLE pipe_write_;
};
} // namespace test
} // namespace crashpad
#endif // CRASHPAD_TEST_WIN_WIN_CHILD_PROCESS_H_