usr/src/lib/libc/port/sys/lockf.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1988 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 #include <sys/feature_tests.h>
  33
  34 #if !defined(_LP64) && _FILE_OFFSET_BITS == 64
  35 #define __lockf         __lockf64
  36 #endif
  37
  38 #include "lint.h"
  39 #include <sys/types.h>
  40 #include <unistd.h>
  41 #include <errno.h>
  42 #include <fcntl.h>
  43
  44 int
  45 __lockf(int fildes, int function, off_t size)
  46 {
  47         struct flock l;
  48         int rv;
  49
  50         l.l_whence = 1;
  51         if (size < 0) {
  52                 l.l_start = size;
  53                 l.l_len = -size;
  54         } else {
  55                 l.l_start = (off_t)0;
  56                 l.l_len = size;
  57         }
  58         switch (function) {
  59         case F_ULOCK:
  60                 l.l_type = F_UNLCK;
  61                 rv = fcntl(fildes, F_SETLK, &l);
  62                 break;
  63         case F_LOCK:
  64                 l.l_type = F_WRLCK;
  65                 rv = fcntl(fildes, F_SETLKW, &l);
  66                 break;
  67         case F_TLOCK:
  68                 l.l_type = F_WRLCK;
  69                 rv = fcntl(fildes, F_SETLK, &l);
  70                 break;
  71         case F_TEST:
  72                 l.l_type = F_WRLCK;
  73                 rv = fcntl(fildes, F_GETLK, &l);
  74                 if (rv != -1) {
  75                         if (l.l_type == F_UNLCK)
  76                                 return (0);
  77                         else {
  78                                 errno = EAGAIN;
  79                                 return (-1);
  80                         }
  81                 }
  82                 break;
  83         default:
  84                 errno = EINVAL;
  85                 return (-1);
  86         }
  87         if (rv < 0) {
  88                 switch (errno) {
  89                 case EMFILE:
  90                 case ENOSPC:
  91                 case ENOLCK:
  92                         /*
  93                          * A deadlock error is given if we run out of resources,
  94                          * in compliance with /usr/group standards.
  95                          */
  96                         errno = EDEADLK;
  97                         break;
  98                 default:
  99                         break;
 100                 }
 101         }
 102         return (rv);
 103 }