bsd/sys/sem.h

   1 /*
   2  * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_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
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /*      $NetBSD: sem.h,v 1.5 1994/06/29 06:45:15 cgd Exp $      */
  31
  32 /*
  33  * SVID compatible sem.h file
  34  *
  35  * Author:  Daniel Boulet
  36  * John Bellardo modified the implementation for Darwin. 12/2000
  37  */
  38
  39 #ifndef _SYS_SEM_H_
  40 #define _SYS_SEM_H_
  41
  42
  43 #include <sys/cdefs.h>
  44 #include <sys/_types.h>
  45
  46 /*
  47  * [XSI]        All of the symbols from <sys/ipc.h> SHALL be defined
  48  *              when this header is included
  49  */
  50 #include <sys/ipc.h>
  51
  52
  53 /*
  54  * [XSI] The pid_t, time_t, key_t, and size_t types shall be defined as
  55  * described in <sys/types.h>.
  56  *
  57  * NOTE:        The definition of the key_t type is implicit from the
  58  *              inclusion of <sys/ipc.h>
  59  */
  60 #ifndef _PID_T
  61 typedef __darwin_pid_t  pid_t;
  62 #define _PID_T
  63 #endif
  64
  65 #ifndef _TIME_T
  66 #define _TIME_T
  67 typedef __darwin_time_t time_t;
  68 #endif
  69
  70 #ifndef _SIZE_T
  71 #define _SIZE_T
  72 typedef __darwin_size_t size_t;
  73 #endif
  74
  75 /*
  76  * Technically, we should force all code references to the new structure
  77  * definition, not in just the standards conformance case, and leave the
  78  * legacy interface there for binary compatibility only.  Currently, we
  79  * are only forcing this for programs requesting standards conformance.
  80  */
  81 #if defined(__POSIX_C_SOURCE) || defined(kernel) || defined(__LP64__)
  82 /*
  83  * Structure used internally.
  84  *
  85  * This structure is exposed because standards dictate that it is used as
  86  * the semun union member 'buf' as the fourth argment to semctl() when the
  87  * third argument is IPC_STAT or IPC_SET.
  88  *
  89  * Note: only the fields sem_perm, sem_nsems, sem_otime, and sem_ctime
  90  * are meaningful in user space.
  91  */
  92 struct __semid_ds_new {
  93         struct __ipc_perm_new sem_perm; /* [XSI] operation permission struct */
  94         __int32_t       sem_base;       /* 32 bit base ptr for semaphore set */
  95         unsigned short  sem_nsems;      /* [XSI] number of sems in set */
  96         time_t          sem_otime;      /* [XSI] last operation time */
  97         __int32_t       sem_pad1;       /* RESERVED: DO NOT USE! */
  98         time_t          sem_ctime;      /* [XSI] last change time */
  99                                         /* Times measured in secs since */
 100                                         /* 00:00:00 GMT, Jan. 1, 1970 */
 101         __int32_t       sem_pad2;       /* RESERVED: DO NOT USE! */
 102         __int32_t       sem_pad3[4];    /* RESERVED: DO NOT USE! */
 103 };
 104 #define semid_ds        __semid_ds_new
 105 #else   /* !_POSIX_C_SOURCE */
 106 #define semid_ds        __semid_ds_old
 107 #endif  /* !_POSIX_C_SOURCE */
 108
 109 #if !defined(__POSIX_C_SOURCE) && !defined(__LP64__)
 110 struct __semid_ds_old {
 111         struct __ipc_perm_old sem_perm; /* [XSI] operation permission struct */
 112         __int32_t       sem_base;       /* 32 bit base ptr for semaphore set */
 113         unsigned short  sem_nsems;      /* [XSI] number of sems in set */
 114         time_t          sem_otime;      /* [XSI] last operation time */
 115         __int32_t       sem_pad1;       /* RESERVED: DO NOT USE! */
 116         time_t          sem_ctime;      /* [XSI] last change time */
 117                                         /* Times measured in secs since */
 118                                         /* 00:00:00 GMT, Jan. 1, 1970 */
 119         __int32_t       sem_pad2;       /* RESERVED: DO NOT USE! */
 120         __int32_t       sem_pad3[4];    /* RESERVED: DO NOT USE! */
 121 };
 122 #endif  /* !_POSIX_C_SOURCE */
 123
 124 /*
 125  * Possible values for the third argument to semctl()
 126  */
 127 #define GETNCNT 3       /* [XSI] Return the value of semncnt {READ} */
 128 #define GETPID  4       /* [XSI] Return the value of sempid {READ} */
 129 #define GETVAL  5       /* [XSI] Return the value of semval {READ} */
 130 #define GETALL  6       /* [XSI] Return semvals into arg.array {READ} */
 131 #define GETZCNT 7       /* [XSI] Return the value of semzcnt {READ} */
 132 #define SETVAL  8       /* [XSI] Set the value of semval to arg.val {ALTER} */
 133 #define SETALL  9       /* [XSI] Set semvals from arg.array {ALTER} */
 134
 135
 136 /* A semaphore; this is an anonymous structure, not for external use */
 137 struct sem {
 138         unsigned short  semval;         /* semaphore value */
 139         pid_t           sempid;         /* pid of last operation */
 140         unsigned short  semncnt;        /* # awaiting semval > cval */
 141         unsigned short  semzcnt;        /* # awaiting semval == 0 */
 142 };
 143
 144
 145 /*
 146  * Structure of array element for second argument to semop()
 147  */
 148 struct sembuf {
 149         unsigned short  sem_num;        /* [XSI] semaphore # */
 150         short           sem_op;         /* [XSI] semaphore operation */
 151         short           sem_flg;        /* [XSI] operation flags */
 152 };
 153
 154 /*
 155  * Possible flag values for sem_flg
 156  */
 157 #define SEM_UNDO        010000          /* [XSI] Set up adjust on exit entry */
 158
 159
 160 #ifndef _POSIX_C_SOURCE
 161
 162 /*
 163  * System imposed limit on the value of the third parameter to semop().
 164  * This is arbitrary, and the standards unfortunately do not provide a
 165  * way for user applications to retrieve this value (e.g. via sysconf()
 166  * or from a manifest value in <unistd.h>).  The value shown here is
 167  * informational, and subject to change in future revisions.
 168  */
 169 #define MAX_SOPS        5       /* maximum # of sembuf's per semop call */
 170
 171
 172 /*
 173  * Union used as the fourth argment to semctl() in all cases.  Specific
 174  * member values are used for different values of the third parameter:
 175  *
 176  * Command                                      Member
 177  * -------------------------------------------  ------
 178  * GETALL, SETALL                               array
 179  * SETVAL                                       val
 180  * IPC_STAT, IPC_SET                            buf
 181  *
 182  * The union definition is intended to be defined by the user application
 183  * in conforming applications; it is provided here for two reasons:
 184  *
 185  * 1)   Historical source compatability for non-conforming applications
 186  *      expecting this header to declare the union type on their behalf
 187  *
 188  * 2)   Documentation; specifically, 64 bit applications that do not pass
 189  *      this structure for 'val', or, alternately, a 64 bit type, will
 190  *      not function correctly
 191  */
 192 union semun {
 193         int             val;            /* value for SETVAL */
 194         struct semid_ds *buf;           /* buffer for IPC_STAT & IPC_SET */
 195         unsigned short  *array;         /* array for GETALL & SETALL */
 196 };
 197 typedef union semun semun_t;
 198
 199
 200 /*
 201  * Permissions
 202  */
 203 #define SEM_A           0200    /* alter permission */
 204 #define SEM_R           0400    /* read permission */
 205
 206 #endif  /* !_POSIX_C_SOURCE */
 207
 208
 209
 210 #ifndef KERNEL
 211
 212 __BEGIN_DECLS
 213 #ifndef _POSIX_C_SOURCE
 214 int     semsys(int, ...);
 215 #endif /* !_POSIX_C_SOURCE */
 216 int     semctl(int, int, int, ...) __DARWIN_ALIAS(semctl);
 217 int     semget(key_t, int, int);
 218 int     semop(int, struct sembuf *, size_t);
 219 __END_DECLS
 220
 221 #endif /* !KERNEL */
 222
 223 #endif /* !_SEM_H_ */