/* $FreeBSD: src/sys/kern/sysv_sem.c,v 1.69 2004/03/17 09:37:13 cperciva Exp $ */

/*
 * Implementation of SVID semaphores
 *
 * Author:  Daniel Boulet
 * Copyright (c) 2013 Larisa Grigore <larisagrigore@gmail.com>
 *
 * This software is provided ``AS IS'' without any warranties of any kind.
 */

#ifndef _SYSVIPC_SEM_H_
#define _SYSVIPC_SEM_H_

#include <sys/sem.h>

#include "sysvipc_lock.h"
#include "sysvipc_lock_generic.h"

//#define SYSV_SEMS
                /* Used to define if each semaphore in the
                 * set is protected by a mutex, the entire
                 * group being protected by a read lock.
                 * If SYSV_SEMS is not defined, then the entire
                 * group is protected only by a write lock.
                 */
struct sem {
        u_short semval;         /* semaphore value */
        pid_t   sempid;         /* pid of last operation */
        u_short semncnt;        /* # awaiting semval > cval */
        u_short semzcnt;        /* # awaiting semval = 0 */
#ifdef SYSV_SEMS
        struct sysv_mutex sem_mutex;
#endif
};

/* Used internally. The struct semid_ds is used only
 * by caller, as argument to semctl.
 */
struct semid_ds_internal {
        struct  ipc_perm sem_perm;      /* operation permission struct */
        u_short sem_nsems;      /* number of sems in set */
        time_t  sem_otime;      /* last operation time */
        time_t  sem_ctime;      /* last change time */
                                /* Times measured in secs since */
                                /* 00:00:00 GMT, Jan. 1, 1970 */
        struct  sem sem_base[0];        /* pointer to first semaphore in set */
};

struct semid_pool {
#ifdef SYSV_RWLOCK
        struct sysv_rwlock rwlock;
#else
        struct sysv_mutex mutex;
#endif
        struct semid_ds_internal ds;
        char gen;
};

/*
 * Undo structure (one per process)
 */
struct sem_undo {
//      pthread_rwlock_t un_lock;
        int     un_pages;
        short   un_cnt;                 /* # of active entries */
        short   un_unused;
        struct undo {
                short   un_adjval;      /* adjust on exit values */
                short   un_num;         /* semaphore # */
                int     un_id;          /* semid */
        } un_ent[0];                    /* undo entries */
};

int sysvipc___semctl(int, int, int, union semun *);
int sysvipc_semget(key_t, int, int);
int sysvipc_semop(int, struct sembuf *, unsigned);

#endif /* !_SYSVIPC_SEM_H_ */