usr/src/lib/libc/port/stdio/flockf.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) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
  28 /* All Rights Reserved */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 #include "lint.h"
  33 #include "mtlib.h"
  34 #include "file64.h"
  35 #include <stdio.h>
  36 #include <thread.h>
  37 #include <synch.h>
  38 #include <stdlib.h>
  39 #include <errno.h>
  40 #include <stdio_ext.h>
  41 #include "stdiom.h"
  42
  43 #define _iob    __iob
  44
  45 /*
  46  * _flockget and _flockrel are only called by the
  47  * FLOCKFILE/FUNLOCKFILE macros in mtlib.h.
  48  */
  49
  50 /*
  51  * compute the lock's position, acquire it and return its pointer
  52  */
  53
  54 rmutex_t *
  55 _flockget(FILE *iop)
  56 {
  57         rmutex_t *rl = IOB_LCK(iop);
  58
  59         if (rl != NULL)
  60                 cancel_safe_mutex_lock(rl);
  61         return (rl);
  62 }
  63
  64 int
  65 ftrylockfile(FILE *iop)
  66 {
  67         rmutex_t *rl = IOB_LCK(iop);
  68
  69         if (rl != NULL)
  70                 return (mutex_trylock(rl));
  71         return (0);     /* can't happen? */
  72 }
  73
  74 void
  75 flockfile(FILE *iop)
  76 {
  77         rmutex_t *rl = IOB_LCK(iop);
  78
  79         if (rl != NULL)
  80                 (void) mutex_lock(rl);
  81 }
  82
  83 void
  84 funlockfile(FILE *iop)
  85 {
  86         rmutex_t *rl = IOB_LCK(iop);
  87
  88         if (rl != NULL)
  89                 (void) mutex_unlock(rl);
  90 }
  91
  92 int
  93 __fsetlocking(FILE *iop, int type)
  94 {
  95         int     ret = 0;
  96
  97         ret = GET_IONOLOCK(iop) ? FSETLOCKING_BYCALLER : FSETLOCKING_INTERNAL;
  98
  99         switch (type) {
 100
 101         case FSETLOCKING_QUERY:
 102                 break;
 103
 104         case FSETLOCKING_INTERNAL:
 105                 CLEAR_IONOLOCK(iop);
 106                 break;
 107
 108         case FSETLOCKING_BYCALLER:
 109                 SET_IONOLOCK(iop);
 110                 break;
 111
 112         default:
 113                 errno = EINVAL;
 114                 return (-1);
 115         }
 116
 117         return (ret);
 118 }