Process.hpp

/* This file is part of Raul.
 * Copyright (C) 2007-2009 David Robillard <http://drobilla.net>
 *
 * Raul is free software; you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * Raul is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef RAUL_PROCESS_HPP
#define RAUL_PROCESS_HPP

#include <sys/resource.h>
#include <sys/time.h>
#include <unistd.h>

#include <iostream>
#include <string>

#include <boost/utility.hpp>

#include "raul/log.hpp"

namespace Raul {


class Process : boost::noncopyable
{
public:

    static bool launch(const std::string& command) {
        const std::string executable = (command.find(" ") != std::string::npos)
            ? command.substr(0, command.find(" "))
            : command;

        const std::string arguments = command.substr((command.find(" ") + 1));

        info << "Launching child process '" << executable << "' with arguments '"
            << arguments << "'" << std::endl;

        // Use the same double fork() trick as JACK to prevent zombie children
        const int err = fork();

        if (err == 0) {
            // (child)

            // close all nonstandard file descriptors
            struct rlimit max_fds;
            getrlimit(RLIMIT_NOFILE, &max_fds);

            for (rlim_t fd = 3; fd < max_fds.rlim_cur; ++fd)
                close(fd);

            switch (fork()) {
                case 0:
                    // (grandchild)
                    setsid();
                    execlp(executable.c_str(), arguments.c_str(), NULL);
                    _exit(-1);

                case -1:
                    // (second) fork failed, there is no grandchild
                    _exit (-1);

                    /* exit the child process here */
                default:
                    _exit (0);
            }
        }

        return (err > 0);
    }

private:
    Process() {}
};


} // namespace Raul

#endif // RAUL_PROCESS_HPP