/*
* 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