sys/semctl.c

   1 /*
   2  * Copyright (c) 2004 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 #include <unistd.h>
  24 #include <stdarg.h>
  25 #include <sys/sem.h>
  26
  27 #include <errno.h>
  28 /*
  29  * Because KERNEL is defined, including errno.h doesn't define errno, so
  30  * we have to do it ourselves.
  31  */
  32 extern int * __error(void);
  33 #define errno (*__error())
  34
  35 /*
  36  * Legacy stub to account for the differences in the ipc_perm structure,
  37  * while maintaining binary backward compatibility.
  38  */
  39 extern int __semctl(int semid, int semnum, int cmd, void *);
  40
  41 int
  42 semctl(int semid, int semnum, int cmd, ...)
  43 {
  44         va_list                 ap;
  45         int                     rv;
  46         int                     val = 0;
  47         struct __semid_ds_new   ds;
  48         struct __semid_ds_new   *ds_new = &ds;
  49         struct __semid_ds_old   *ds_old = NULL;
  50
  51         va_start(ap, cmd);
  52         if (cmd == SETVAL)
  53                 val = va_arg(ap, int);
  54         else
  55                 ds_old = va_arg(ap, struct __semid_ds_old *);
  56         va_end(ap);
  57
  58 #define _UP_CVT(x)      ds_new-> x = ds_old-> x
  59 #define _DN_CVT(x)      ds_old-> x = ds_new-> x
  60
  61         if ((cmd == IPC_SET || cmd == IPC_STAT) && ds_old == NULL) {
  62                 /* Return EFAULT if ds_old is NULL (like the kernel would do) */
  63                 errno = EFAULT;
  64                 return -1;
  65         }
  66         if (cmd == IPC_SET) {
  67                 /* convert before call */
  68                 _UP_CVT(sem_perm.uid);
  69                 _UP_CVT(sem_perm.gid);
  70                 _UP_CVT(sem_perm.cuid);
  71                 _UP_CVT(sem_perm.cgid);
  72                 _UP_CVT(sem_perm.mode);
  73                 ds_new->sem_perm._seq = ds_old->sem_perm.seq;
  74                 ds_new->sem_perm._key = ds_old->sem_perm.key;
  75                 _UP_CVT(sem_base);
  76                 _UP_CVT(sem_nsems);
  77                 _UP_CVT(sem_otime);
  78                 _UP_CVT(sem_pad1);      /* binary compatibility */
  79                 _UP_CVT(sem_ctime);
  80                 _UP_CVT(sem_pad2);      /* binary compatibility */
  81                 _UP_CVT(sem_pad3[0]);   /* binary compatibility */
  82                 _UP_CVT(sem_pad3[1]);   /* binary compatibility */
  83                 _UP_CVT(sem_pad3[2]);   /* binary compatibility */
  84                 _UP_CVT(sem_pad3[3]);   /* binary compatibility */
  85         }
  86         switch (cmd) {
  87         case SETVAL:
  88                 /* syscall must use LP64 quantities */
  89                 rv = __semctl(semid, semnum, cmd, (void *)val);
  90                 break;
  91         case IPC_SET:
  92         case IPC_STAT:
  93                 rv = __semctl(semid, semnum, cmd, ds_new);
  94                 break;
  95         default:
  96                 rv = __semctl(semid, semnum, cmd, ds_old);
  97                 break;
  98         }
  99
 100         if (cmd == IPC_STAT) {
 101                 /* convert after call */
 102                 _DN_CVT(sem_perm.uid);  /* warning!  precision loss! */
 103                 _DN_CVT(sem_perm.gid);  /* warning!  precision loss! */
 104                 _DN_CVT(sem_perm.cuid); /* warning!  precision loss! */
 105                 _DN_CVT(sem_perm.cgid); /* warning!  precision loss! */
 106                 _DN_CVT(sem_perm.mode);
 107                 ds_old->sem_perm.seq = ds_new->sem_perm._seq;
 108                 ds_old->sem_perm.key = ds_new->sem_perm._key;
 109                 _DN_CVT(sem_base);
 110                 _DN_CVT(sem_nsems);
 111                 _DN_CVT(sem_otime);
 112                 _DN_CVT(sem_pad1);      /* binary compatibility */
 113                 _DN_CVT(sem_ctime);
 114                 _DN_CVT(sem_pad2);      /* binary compatibility */
 115                 _DN_CVT(sem_pad3[0]);   /* binary compatibility */
 116                 _DN_CVT(sem_pad3[1]);   /* binary compatibility */
 117                 _DN_CVT(sem_pad3[2]);   /* binary compatibility */
 118                 _DN_CVT(sem_pad3[3]);   /* binary compatibility */
 119         }
 120
 121         return (rv);
 122 }