/*

* Copyright (c)2006-2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:  Implementation of semaphore (POSIX Standard).

*

*/

// INCLUDE FILES

#include <stdarg.h>

#include <errno.h>

#include <sys/ipc.h>

#include <sys/sem.h>

#include <unistd.h>

#include "sysreent.h"

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

// Funcation name: semget

// Description: Get semaphore identifier using the IPC key generated by ftok.

// Returns: None zero number (semaphore identifier): On success

//          -1              : On error.

// In case of error, errno value set to

//          EACCES - Semaphore exists but access denied.

//          EEXIST - A semaphore identifier exists for the argument key but

//                   ((semflg&IPC_CREAT)&&(semflg&IPC_EXCL)) is non-zero.

//          EINVAL - The value of nsems is either less than or equal to 0 or

//                   greater than the system-imposed limit, or a semaphore

//                   identifier exists for the argument key, but the number of

//                   semaphores in the set associated with it is less than nsems

//                   and nsems is not equal to 0.

//          ENOENT - A semaphore identifier does not exist for the argument key

//                   and (semflg&IPC_CREAT) is equal to 0.

//          ENOSPC - A semaphore identifier is to be created but the system-imposed

//                   limit on the maximum number of allowed semaphores system-wide

//                   would be exceeded.

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

//

extern "C" {

EXPORT_C int semget(key_t key, int nsems, int semflg)

    {

    return _semget_r( &errno, key, nsems, semflg);

    }

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

// Funcation name: semop

// Description: Perform atomically a user-defined array of semaphore operations

//              on the set of semaphores associated with the semaphore identifier

//              specified by the argument semid.

// Returns: 0  : On success

//          -1 : On error.

// In case of error, errno value set to

//          E2BIG - The value of nsops is greater than the system-imposed maximum.

//          EACCES - Operation permission is denied to the calling process, see IPC.

//          EAGAIN - The operation would result in suspension of the calling process

//                   but (sem_flg&IPC_NOWAIT) is non-zero.

//          EFBIG - The value of sem_num is less than 0 or greater than or equal to

//                   the number of semaphores in the set associated with semid.

//          EIDRM - The semaphore identifier semid is removed from the system.

//          EINTR - The semop() function was interrupted by a signal.

//          EINVAL - The value of semid is not a valid semaphore identifier, or the

//                   number of individual semaphores for which the calling process

//                   requests a SEM_UNDO would exceed the system-imposed limit.

//          ENOSPC - The limit on the number of individual processes requesting a

//                   SEM_UNDO would be exceeded.

//          ERANGE - An operation would cause a semval to overflow the system-imposed

//                   limit, or an operation would cause a semadj value to overflow the

//                   system-imposed limit

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

//

EXPORT_C int semop(int semid, struct sembuf *sops, unsigned nsops)

    {

    return _semop_r(&errno, semid, sops, nsops);

    }

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

// Funcation name: semctl

// Description: Provides a variety of semaphore control operations as specified by cmd.

// Returns:

//          If successful, the value returned by semctl() depends on cmd as follows:

//                 GETVAL - Value of semval.

//                 GETPID - Value of sempid.

//                 GETNCNT - Value of semncnt.

//                 GETZCNT - Value of semzcnt.

//                 All others, it returns 0.

//          -1 : On error.

// In case of error, errno value set to

//          EACCES - Operation permission is denied to the calling process.

//          EINVAL - The value of semid is not a valid semaphore identifier,

//                   or the value of semnum is less than 0 or greater than or

//                   equal to sem_nsems, or the value of cmd is not a valid command.

//          EPERM - The argument cmd is equal to IPC_RMID or IPC_SET and the

//                   effective user ID of the calling process is not equal to

//                   that of a process with appropriate privileges and it is not

//                   equal to the value of sem_perm.cuid or sem_perm.uid in the

//                   data structure associated with semid.

//          ERANGE - The argument cmd is equal to SETVAL or SETALL and the value

//                   to which semval is to be set is greater than the system-imposed maximum

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

//

EXPORT_C int semctl(int semid, int semnum, int cmd, ...)

    {

	va_list ap;

	union semun semun;

	if (cmd == IPC_SET || cmd == IPC_STAT || cmd == GETALL

	    || cmd == SETVAL || cmd == SETALL)

	    {

		va_start(ap, cmd);

		semun = va_arg(ap, union semun);

		va_end(ap);

		return _semctl_r(&errno, semid, semnum, cmd, semun);

	    }

	else

	    {

		return _semctl_r(&errno, semid, semnum, cmd);

	    }

    }

} // extern "C" {

//  End of File