bsd/sys/sem.h

   1 /*
   2  * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*      $NetBSD: sem.h,v 1.5 1994/06/29 06:45:15 cgd Exp $      */
  29
  30 /*
  31  * SVID compatible sem.h file
  32  *
  33  * Author:  Daniel Boulet
  34  * John Bellardo modified the implementation for Darwin. 12/2000
  35  */
  36
  37 #ifndef _SYS_SEM_H_
  38 #define _SYS_SEM_H_
  39
  40
  41 #include <sys/cdefs.h>
  42 #include <sys/_types.h>
  43
  44 /*
  45  * [XSI]        All of the symbols from <sys/ipc.h> SHALL be defined
  46  *              when this header is included
  47  */
  48 #include <sys/ipc.h>
  49
  50
  51 /*
  52  * [XSI] The pid_t, time_t, key_t, and size_t types shall be defined as
  53  * described in <sys/types.h>.
  54  *
  55  * NOTE:        The definition of the key_t type is implicit from the
  56  *              inclusion of <sys/ipc.h>
  57  */
  58 #ifndef _PID_T
  59 typedef __darwin_pid_t  pid_t;
  60 #define _PID_T
  61 #endif
  62
  63 #ifndef _TIME_T
  64 #define _TIME_T
  65 typedef __darwin_time_t time_t;
  66 #endif
  67
  68 #ifndef _SIZE_T
  69 #define _SIZE_T
  70 typedef __darwin_size_t size_t;
  71 #endif
  72
  73 /*
  74  * Technically, we should force all code references to the new structure
  75  * definition, not in just the standards conformance case, and leave the
  76  * legacy interface there for binary compatibility only.  Currently, we
  77  * are only forcing this for programs requesting standards conformance.
  78  */
  79 #if __DARWIN_UNIX03 || defined(KERNEL)
  80 #pragma pack(4)
  81 /*
  82  * Structure used internally.
  83  *
  84  * This structure is exposed because standards dictate that it is used as
  85  * the semun union member 'buf' as the fourth argment to semctl() when the
  86  * third argument is IPC_STAT or IPC_SET.
  87  *
  88  * Note: only the fields sem_perm, sem_nsems, sem_otime, and sem_ctime
  89  * are meaningful in user space.
  90  */
  91 #if (defined(_POSIX_C_SOURCE) && !defined(_DARWIN_C_SOURCE))
  92 struct semid_ds
  93 #else
  94 #define semid_ds        __semid_ds_new
  95 struct __semid_ds_new
  96 #endif
  97 {
  98         struct __ipc_perm_new sem_perm; /* [XSI] operation permission struct */
  99         __int32_t       sem_base;       /* 32 bit base ptr for semaphore set */
 100         unsigned short  sem_nsems;      /* [XSI] number of sems in set */
 101         time_t          sem_otime;      /* [XSI] last operation time */
 102         __int32_t       sem_pad1;       /* RESERVED: DO NOT USE! */
 103         time_t          sem_ctime;      /* [XSI] last change time */
 104                                         /* Times measured in secs since */
 105                                         /* 00:00:00 GMT, Jan. 1, 1970 */
 106         __int32_t       sem_pad2;       /* RESERVED: DO NOT USE! */
 107         __int32_t       sem_pad3[4];    /* RESERVED: DO NOT USE! */
 108 };
 109 #pragma pack()
 110 #else   /* !__DARWIN_UNIX03 */
 111 #define semid_ds        __semid_ds_old
 112 #endif  /* __DARWIN_UNIX03 */
 113
 114 #if !__DARWIN_UNIX03
 115 struct __semid_ds_old {
 116         struct __ipc_perm_old sem_perm; /* [XSI] operation permission struct */
 117         __int32_t       sem_base;       /* 32 bit base ptr for semaphore set */
 118         unsigned short  sem_nsems;      /* [XSI] number of sems in set */
 119         time_t          sem_otime;      /* [XSI] last operation time */
 120         __int32_t       sem_pad1;       /* RESERVED: DO NOT USE! */
 121         time_t          sem_ctime;      /* [XSI] last change time */
 122                                         /* Times measured in secs since */
 123                                         /* 00:00:00 GMT, Jan. 1, 1970 */
 124         __int32_t       sem_pad2;       /* RESERVED: DO NOT USE! */
 125         __int32_t       sem_pad3[4];    /* RESERVED: DO NOT USE! */
 126 };
 127 #endif  /* !__DARWIN_UNIX03 */
 128
 129 /*
 130  * Possible values for the third argument to semctl()
 131  */
 132 #define GETNCNT 3       /* [XSI] Return the value of semncnt {READ} */
 133 #define GETPID  4       /* [XSI] Return the value of sempid {READ} */
 134 #define GETVAL  5       /* [XSI] Return the value of semval {READ} */
 135 #define GETALL  6       /* [XSI] Return semvals into arg.array {READ} */
 136 #define GETZCNT 7       /* [XSI] Return the value of semzcnt {READ} */
 137 #define SETVAL  8       /* [XSI] Set the value of semval to arg.val {ALTER} */
 138 #define SETALL  9       /* [XSI] Set semvals from arg.array {ALTER} */
 139
 140
 141 /* A semaphore; this is an anonymous structure, not for external use */
 142 struct sem {
 143         unsigned short  semval;         /* semaphore value */
 144         pid_t           sempid;         /* pid of last operation */
 145         unsigned short  semncnt;        /* # awaiting semval > cval */
 146         unsigned short  semzcnt;        /* # awaiting semval == 0 */
 147 };
 148
 149
 150 /*
 151  * Structure of array element for second argument to semop()
 152  */
 153 struct sembuf {
 154         unsigned short  sem_num;        /* [XSI] semaphore # */
 155         short           sem_op;         /* [XSI] semaphore operation */
 156         short           sem_flg;        /* [XSI] operation flags */
 157 };
 158
 159 /*
 160  * Possible flag values for sem_flg
 161  */
 162 #define SEM_UNDO        010000          /* [XSI] Set up adjust on exit entry */
 163
 164
 165 #if !defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE)
 166
 167 /*
 168  * System imposed limit on the value of the third parameter to semop().
 169  * This is arbitrary, and the standards unfortunately do not provide a
 170  * way for user applications to retrieve this value (e.g. via sysconf()
 171  * or from a manifest value in <unistd.h>).  The value shown here is
 172  * informational, and subject to change in future revisions.
 173  */
 174 #define MAX_SOPS        5       /* maximum # of sembuf's per semop call */
 175
 176
 177 /*
 178  * Union used as the fourth argment to semctl() in all cases.  Specific
 179  * member values are used for different values of the third parameter:
 180  *
 181  * Command                                      Member
 182  * -------------------------------------------  ------
 183  * GETALL, SETALL                               array
 184  * SETVAL                                       val
 185  * IPC_STAT, IPC_SET                            buf
 186  *
 187  * The union definition is intended to be defined by the user application
 188  * in conforming applications; it is provided here for two reasons:
 189  *
 190  * 1)   Historical source compatability for non-conforming applications
 191  *      expecting this header to declare the union type on their behalf
 192  *
 193  * 2)   Documentation; specifically, 64 bit applications that do not pass
 194  *      this structure for 'val', or, alternately, a 64 bit type, will
 195  *      not function correctly
 196  */
 197 union semun {
 198         int             val;            /* value for SETVAL */
 199         struct semid_ds *buf;           /* buffer for IPC_STAT & IPC_SET */
 200         unsigned short  *array;         /* array for GETALL & SETALL */
 201 };
 202 typedef union semun semun_t;
 203
 204
 205 /*
 206  * Permissions
 207  */
 208 #define SEM_A           0200    /* alter permission */
 209 #define SEM_R           0400    /* read permission */
 210
 211 #endif  /* (!_POSIX_C_SOURCE || _DARWIN_C_SOURCE) */
 212
 213
 214
 215 #ifndef KERNEL
 216
 217 __BEGIN_DECLS
 218 #if !defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE)
 219 int     semsys(int, ...);
 220 #endif /* (!_POSIX_C_SOURCE || _DARWIN_C_SOURCE) */
 221 int     semctl(int, int, int, ...) __DARWIN_ALIAS(semctl);
 222 int     semget(key_t, int, int);
 223 int     semop(int, struct sembuf *, size_t);
 224 __END_DECLS
 225
 226 #endif /* !KERNEL */
 227
 228 #endif /* !_SEM_H_ */