bsd/sys/sem.h

   1 /*
   2  * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*      $NetBSD: sem.h,v 1.5 1994/06/29 06:45:15 cgd Exp $      */
  23
  24 /*
  25  * SVID compatible sem.h file
  26  *
  27  * Author:  Daniel Boulet
  28  * John Bellardo modified the implementation for Darwin. 12/2000
  29  */
  30
  31 #ifndef _SYS_SEM_H_
  32 #define _SYS_SEM_H_
  33
  34
  35 #include <sys/cdefs.h>
  36 #include <sys/_types.h>
  37
  38 /*
  39  * [XSI]        All of the symbols from <sys/ipc.h> SHALL be defined
  40  *              when this header is included
  41  */
  42 #include <sys/ipc.h>
  43
  44
  45 /*
  46  * [XSI] The pid_t, time_t, key_t, and size_t types shall be defined as
  47  * described in <sys/types.h>.
  48  *
  49  * NOTE:        The definition of the key_t type is implicit from the
  50  *              inclusion of <sys/ipc.h>
  51  */
  52 #ifndef _PID_T
  53 typedef __darwin_pid_t  pid_t;
  54 #define _PID_T
  55 #endif
  56
  57 #ifndef _TIME_T
  58 #define _TIME_T
  59 typedef __darwin_time_t time_t;
  60 #endif
  61
  62 #ifndef _SIZE_T
  63 #define _SIZE_T
  64 typedef __darwin_size_t size_t;
  65 #endif
  66
  67 /*
  68  * Technically, we should force all code references to the new structure
  69  * definition, not in just the standards conformance case, and leave the
  70  * legacy interface there for binary compatibility only.  Currently, we
  71  * are only forcing this for programs requesting standards conformance.
  72  */
  73 #if defined(__POSIX_C_SOURCE) || defined(kernel) || defined(__LP64__)
  74 /*
  75  * Structure used internally.
  76  *
  77  * This structure is exposed because standards dictate that it is used as
  78  * the semun union member 'buf' as the fourth argment to semctl() when the
  79  * third argument is IPC_STAT or IPC_SET.
  80  *
  81  * Note: only the fields sem_perm, sem_nsems, sem_otime, and sem_ctime
  82  * are meaningful in user space.
  83  */
  84 struct __semid_ds_new {
  85         struct __ipc_perm_new sem_perm; /* [XSI] operation permission struct */
  86         __int32_t       sem_base;       /* 32 bit base ptr for semaphore set */
  87         unsigned short  sem_nsems;      /* [XSI] number of sems in set */
  88         time_t          sem_otime;      /* [XSI] last operation time */
  89         __int32_t       sem_pad1;       /* RESERVED: DO NOT USE! */
  90         time_t          sem_ctime;      /* [XSI] last change time */
  91                                         /* Times measured in secs since */
  92                                         /* 00:00:00 GMT, Jan. 1, 1970 */
  93         __int32_t       sem_pad2;       /* RESERVED: DO NOT USE! */
  94         __int32_t       sem_pad3[4];    /* RESERVED: DO NOT USE! */
  95 };
  96 #define semid_ds        __semid_ds_new
  97 #else   /* !_POSIX_C_SOURCE */
  98 #define semid_ds        __semid_ds_old
  99 #endif  /* !_POSIX_C_SOURCE */
 100
 101 #if !defined(__POSIX_C_SOURCE) && !defined(__LP64__)
 102 struct __semid_ds_old {
 103         struct __ipc_perm_old sem_perm; /* [XSI] operation permission struct */
 104         __int32_t       sem_base;       /* 32 bit base ptr for semaphore set */
 105         unsigned short  sem_nsems;      /* [XSI] number of sems in set */
 106         time_t          sem_otime;      /* [XSI] last operation time */
 107         __int32_t       sem_pad1;       /* RESERVED: DO NOT USE! */
 108         time_t          sem_ctime;      /* [XSI] last change time */
 109                                         /* Times measured in secs since */
 110                                         /* 00:00:00 GMT, Jan. 1, 1970 */
 111         __int32_t       sem_pad2;       /* RESERVED: DO NOT USE! */
 112         __int32_t       sem_pad3[4];    /* RESERVED: DO NOT USE! */
 113 };
 114 #endif  /* !_POSIX_C_SOURCE */
 115
 116 /*
 117  * Possible values for the third argument to semctl()
 118  */
 119 #define GETNCNT 3       /* [XSI] Return the value of semncnt {READ} */
 120 #define GETPID  4       /* [XSI] Return the value of sempid {READ} */
 121 #define GETVAL  5       /* [XSI] Return the value of semval {READ} */
 122 #define GETALL  6       /* [XSI] Return semvals into arg.array {READ} */
 123 #define GETZCNT 7       /* [XSI] Return the value of semzcnt {READ} */
 124 #define SETVAL  8       /* [XSI] Set the value of semval to arg.val {ALTER} */
 125 #define SETALL  9       /* [XSI] Set semvals from arg.array {ALTER} */
 126
 127
 128 /* A semaphore; this is an anonymous structure, not for external use */
 129 struct sem {
 130         unsigned short  semval;         /* semaphore value */
 131         pid_t           sempid;         /* pid of last operation */
 132         unsigned short  semncnt;        /* # awaiting semval > cval */
 133         unsigned short  semzcnt;        /* # awaiting semval == 0 */
 134 };
 135
 136
 137 /*
 138  * Structure of array element for second argument to semop()
 139  */
 140 struct sembuf {
 141         unsigned short  sem_num;        /* [XSI] semaphore # */
 142         short           sem_op;         /* [XSI] semaphore operation */
 143         short           sem_flg;        /* [XSI] operation flags */
 144 };
 145
 146 /*
 147  * Possible flag values for sem_flg
 148  */
 149 #define SEM_UNDO        010000          /* [XSI] Set up adjust on exit entry */
 150
 151
 152 #ifndef _POSIX_C_SOURCE
 153
 154 /*
 155  * System imposed limit on the value of the third parameter to semop().
 156  * This is arbitrary, and the standards unfortunately do not provide a
 157  * way for user applications to retrieve this value (e.g. via sysconf()
 158  * or from a manifest value in <unistd.h>).  The value shown here is
 159  * informational, and subject to change in future revisions.
 160  */
 161 #define MAX_SOPS        5       /* maximum # of sembuf's per semop call */
 162
 163
 164 /*
 165  * Union used as the fourth argment to semctl() in all cases.  Specific
 166  * member values are used for different values of the third parameter:
 167  *
 168  * Command                                      Member
 169  * -------------------------------------------  ------
 170  * GETALL, SETALL                               array
 171  * SETVAL                                       val
 172  * IPC_STAT, IPC_SET                            buf
 173  *
 174  * The union definition is intended to be defined by the user application
 175  * in conforming applications; it is provided here for two reasons:
 176  *
 177  * 1)   Historical source compatability for non-conforming applications
 178  *      expecting this header to declare the union type on their behalf
 179  *
 180  * 2)   Documentation; specifically, 64 bit applications that do not pass
 181  *      this structure for 'val', or, alternately, a 64 bit type, will
 182  *      not function correctly
 183  */
 184 union semun {
 185         int             val;            /* value for SETVAL */
 186         struct semid_ds *buf;           /* buffer for IPC_STAT & IPC_SET */
 187         unsigned short  *array;         /* array for GETALL & SETALL */
 188 };
 189 typedef union semun semun_t;
 190
 191
 192 /*
 193  * Permissions
 194  */
 195 #define SEM_A           0200    /* alter permission */
 196 #define SEM_R           0400    /* read permission */
 197
 198 #endif  /* !_POSIX_C_SOURCE */
 199
 200
 201
 202 #ifndef KERNEL
 203
 204 __BEGIN_DECLS
 205 #ifndef _POSIX_C_SOURCE
 206 int     semsys(int, ...);
 207 #endif /* !_POSIX_C_SOURCE */
 208 int     semctl(int, int, int, ...) __DARWIN_ALIAS(semctl);
 209 int     semget(key_t, int, int);
 210 int     semop(int, struct sembuf *, size_t);
 211 __END_DECLS
 212
 213 #endif /* !KERNEL */
 214
 215 #endif /* !_SEM_H_ */