bsd/sys/sem.h

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