ipc.h

Go to the documentation of this file.

/*
 *              ipc.h
 *
 *      Copyright 2007 - 2016 Brenton Ross
 *
 *      This file is part of VICI.
 *
 *   VICI 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 3 of the License, or
 *   (at your option) any later version.
 *
 *   VICI 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 more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with VICI.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef CFI_IPC_H
#define CFI_IPC_H

#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include "stringy.h"

namespace VICI
{


namespace cfi
{

// -----------------------------------------------------------------


class Semaphore
{
private:
        int semid;
        static const Path & getKeyFile();
        static bool useIPC;
        static struct sembuf Pexclusive[1];
        static struct sembuf Vexclusive[1];
        static struct sembuf Presource[1];
        static struct sembuf Vresource[1];
        static const int NSEMS = 2;

        // as specified in the man page for semctl
    union semun {
        int              val;    /* Value for SETVAL */
        struct semid_ds *buf;    /* Buffer for IPC_STAT, IPC_SET */
        unsigned short  *array;  /* Array for GETALL, SETALL */
        struct seminfo  *__buf;  /* Buffer for IPC_INFO
                                    (Linux-specific) */
    };


public:

        Semaphore( char id ); // id is a single character that identifies this usage.

        ~Semaphore();

        void acquire();

        void release();
};

// -----------------------------------------------------------------


class SemaphoreLock
{
        Semaphore &sem;
public:

        explicit SemaphoreLock( Semaphore & s);

        ~SemaphoreLock();
};

} // namespace cfi
} // namespace VICI

#endif /* LOCK_H_ */

// -------------------------------- end ---------------------------------