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[apple/xnu.git] / bsd / sys / sem.h

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 * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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/*	$NetBSD: sem.h,v 1.5 1994/06/29 06:45:15 cgd Exp $	*/

/*
 * SVID compatible sem.h file
 *
 * Author:  Daniel Boulet
 * John Bellardo modified the implementation for Darwin. 12/2000
 */

#ifndef _SYS_SEM_H_
#define _SYS_SEM_H_


#include <sys/cdefs.h>
#include <sys/_types.h>
#include <machine/types.h> /* __int32_t */

/*
 * [XSI]	All of the symbols from <sys/ipc.h> SHALL be defined
 *		when this header is included
 */
#include <sys/ipc.h>


/*
 * [XSI] The pid_t, time_t, key_t, and size_t types shall be defined as
 * described in <sys/types.h>.
 *
 * NOTE:	The definition of the key_t type is implicit from the
 *		inclusion of <sys/ipc.h>
 */
#include <sys/_types/_pid_t.h>
#include <sys/_types/_time_t.h>
#include <sys/_types/_size_t.h>

/*
 * Technically, we should force all code references to the new structure
 * definition, not in just the standards conformance case, and leave the
 * legacy interface there for binary compatibility only.  Currently, we
 * are only forcing this for programs requesting standards conformance.
 */
#if __DARWIN_UNIX03 || defined(KERNEL)
#pragma pack(4)
/*
 * Structure used internally.
 *
 * This structure is exposed because standards dictate that it is used as
 * the semun union member 'buf' as the fourth argment to semctl() when the
 * third argument is IPC_STAT or IPC_SET.
 *
 * Note: only the fields sem_perm, sem_nsems, sem_otime, and sem_ctime
 * are meaningful in user space.
 */
#if (defined(_POSIX_C_SOURCE) && !defined(_DARWIN_C_SOURCE))
struct semid_ds
#else
#define semid_ds        __semid_ds_new
struct __semid_ds_new
#endif
{
	struct __ipc_perm_new sem_perm; /* [XSI] operation permission struct */
	__int32_t       sem_base;       /* 32 bit base ptr for semaphore set */
	unsigned short  sem_nsems;      /* [XSI] number of sems in set */
	time_t          sem_otime;      /* [XSI] last operation time */
	__int32_t       sem_pad1;       /* RESERVED: DO NOT USE! */
	time_t          sem_ctime;      /* [XSI] last change time */
	                                /* Times measured in secs since */
	                                /* 00:00:00 GMT, Jan. 1, 1970 */
	__int32_t       sem_pad2;       /* RESERVED: DO NOT USE! */
	__int32_t       sem_pad3[4];    /* RESERVED: DO NOT USE! */
};
#pragma pack()
#else   /* !__DARWIN_UNIX03 */
#define semid_ds        __semid_ds_old
#endif  /* __DARWIN_UNIX03 */

#if !__DARWIN_UNIX03
struct __semid_ds_old {
	struct __ipc_perm_old sem_perm; /* [XSI] operation permission struct */
	__int32_t       sem_base;       /* 32 bit base ptr for semaphore set */
	unsigned short  sem_nsems;      /* [XSI] number of sems in set */
	time_t          sem_otime;      /* [XSI] last operation time */
	__int32_t       sem_pad1;       /* RESERVED: DO NOT USE! */
	time_t          sem_ctime;      /* [XSI] last change time */
	                                /* Times measured in secs since */
	                                /* 00:00:00 GMT, Jan. 1, 1970 */
	__int32_t       sem_pad2;       /* RESERVED: DO NOT USE! */
	__int32_t       sem_pad3[4];    /* RESERVED: DO NOT USE! */
};
#endif  /* !__DARWIN_UNIX03 */

/*
 * Possible values for the third argument to semctl()
 */
#define GETNCNT 3       /* [XSI] Return the value of semncnt {READ} */
#define GETPID  4       /* [XSI] Return the value of sempid {READ} */
#define GETVAL  5       /* [XSI] Return the value of semval {READ} */
#define GETALL  6       /* [XSI] Return semvals into arg.array {READ} */
#define GETZCNT 7       /* [XSI] Return the value of semzcnt {READ} */
#define SETVAL  8       /* [XSI] Set the value of semval to arg.val {ALTER} */
#define SETALL  9       /* [XSI] Set semvals from arg.array {ALTER} */


/* A semaphore; this is an anonymous structure, not for external use */
struct sem {
	unsigned short  semval;         /* semaphore value */
	pid_t           sempid;         /* pid of last operation */
	unsigned short  semncnt;        /* # awaiting semval > cval */
	unsigned short  semzcnt;        /* # awaiting semval == 0 */
};


/*
 * Structure of array element for second argument to semop()
 */
struct sembuf {
	unsigned short  sem_num;        /* [XSI] semaphore # */
	short           sem_op;         /* [XSI] semaphore operation */
	short           sem_flg;        /* [XSI] operation flags */
};

/*
 * Possible flag values for sem_flg
 */
#define SEM_UNDO        010000          /* [XSI] Set up adjust on exit entry */


#if !defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE)

/*
 * Union used as the fourth argment to semctl() in all cases.  Specific
 * member values are used for different values of the third parameter:
 *
 * Command					Member
 * -------------------------------------------	------
 * GETALL, SETALL				array
 * SETVAL					val
 * IPC_STAT, IPC_SET				buf
 *
 * The union definition is intended to be defined by the user application
 * in conforming applications; it is provided here for two reasons:
 *
 * 1)	Historical source compatability for non-conforming applications
 *	expecting this header to declare the union type on their behalf
 *
 * 2)	Documentation; specifically, 64 bit applications that do not pass
 *	this structure for 'val', or, alternately, a 64 bit type, will
 *	not function correctly
 */
union semun {
	int             val;            /* value for SETVAL */
	struct semid_ds *buf;           /* buffer for IPC_STAT & IPC_SET */
	unsigned short  *array;         /* array for GETALL & SETALL */
};
typedef union semun semun_t;


/*
 * Permissions
 */
#define SEM_A           0200    /* alter permission */
#define SEM_R           0400    /* read permission */

#endif  /* (!_POSIX_C_SOURCE || _DARWIN_C_SOURCE) */



#ifndef KERNEL

__BEGIN_DECLS
#if !defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE)
int     semsys(int, ...);
#endif /* (!_POSIX_C_SOURCE || _DARWIN_C_SOURCE) */
int     semctl(int, int, int, ...) __DARWIN_ALIAS(semctl);
int     semget(key_t, int, int);
int     semop(int, struct sembuf *, size_t);
__END_DECLS

#endif /* !KERNEL */

#endif /* !_SEM_H_ */