poco/Foundation/include/Poco/Process_UNIX.h
Mike Gelfand 0425866486 Allow for process termination when polling with isRunning
On *NIX, one needs to call `waitpid()` in order for process to exit the
zombie state. If one uses `Process::isRunning()` to emulate non-blocking
wait for child process termination, process will stay zombie and function
will always return true.

This commit changes `Process::isRunning()` to call `waitpid()` with
`WNOHANG` instead of using `kill()` when checking for child process (i.e.
the one we have ProcessHandle for), which allows for process termination.
Additional trickery with mutex and event is needed to prevent exceptions
when `Process::isRunning()` and/or `Process::wait()` is called concurrently
on the same handle from different threads.

Fixes #1097.
2016-01-09 02:36:55 +03:00

96 lines
1.9 KiB
C++

//
// Process_UNIX.h
//
// $Id: //poco/1.4/Foundation/include/Poco/Process_UNIX.h#3 $
//
// Library: Foundation
// Package: Processes
// Module: Process
//
// Definition of the ProcessImpl class for Unix.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_Process_UNIX_INCLUDED
#define Foundation_Process_UNIX_INCLUDED
#include "Poco/Foundation.h"
#include "Poco/Event.h"
#include "Poco/Mutex.h"
#include "Poco/Optional.h"
#include "Poco/RefCountedObject.h"
#include <unistd.h>
#include <vector>
#include <map>
namespace Poco {
class Pipe;
class Foundation_API ProcessHandleImpl: public RefCountedObject
{
public:
ProcessHandleImpl(pid_t pid);
~ProcessHandleImpl();
pid_t id() const;
int wait() const;
int wait(int options) const;
private:
const pid_t _pid;
mutable FastMutex _mutex;
mutable Event _event;
mutable Optional<int> _status;
};
class Foundation_API ProcessImpl
{
public:
typedef pid_t PIDImpl;
typedef std::vector<std::string> ArgsImpl;
typedef std::map<std::string, std::string> EnvImpl;
static PIDImpl idImpl();
static void timesImpl(long& userTime, long& kernelTime);
static ProcessHandleImpl* launchImpl(
const std::string& command,
const ArgsImpl& args,
const std::string& initialDirectory,
Pipe* inPipe,
Pipe* outPipe,
Pipe* errPipe,
const EnvImpl& env);
static void killImpl(ProcessHandleImpl& handle);
static void killImpl(PIDImpl pid);
static bool isRunningImpl(const ProcessHandleImpl& handle);
static bool isRunningImpl(PIDImpl pid);
static void requestTerminationImpl(PIDImpl pid);
private:
static ProcessHandleImpl* launchByForkExecImpl(
const std::string& command,
const ArgsImpl& args,
const std::string& initialDirectory,
Pipe* inPipe,
Pipe* outPipe,
Pipe* errPipe,
const EnvImpl& env);
};
} // namespace Poco
#endif // Foundation_Process_UNIX_INCLUDED