src/external/heimdal/roken/flock.c

   1 /*
   2  * Copyright (c) 1995, 1996, 1997 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <config.h>
  35
  36 #ifndef HAVE_FLOCK
  37
  38 #include "roken.h"
  39
  40 #define OP_MASK (LOCK_SH | LOCK_EX | LOCK_UN)
  41
  42
  43 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
  44 rk_flock(int fd, int operation)
  45 {
  46 #if defined(HAVE_FCNTL) && defined(F_SETLK)
  47   struct flock arg;
  48   int code, cmd;
  49
  50   arg.l_whence = SEEK_SET;
  51   arg.l_start = 0;
  52   arg.l_len = 0;                /* means to EOF */
  53
  54   if (operation & LOCK_NB)
  55     cmd = F_SETLK;
  56   else
  57     cmd = F_SETLKW;             /* Blocking */
  58
  59   switch (operation & OP_MASK) {
  60   case LOCK_UN:
  61     arg.l_type = F_UNLCK;
  62     code = fcntl(fd, F_SETLK, &arg);
  63     break;
  64   case LOCK_SH:
  65     arg.l_type = F_RDLCK;
  66     code = fcntl(fd, cmd, &arg);
  67     break;
  68   case LOCK_EX:
  69     arg.l_type = F_WRLCK;
  70     code = fcntl(fd, cmd, &arg);
  71     break;
  72   default:
  73     errno = EINVAL;
  74     code = -1;
  75     break;
  76   }
  77   return code;
  78
  79 #elif defined(_WIN32)
  80   /* Windows */
  81
  82 #define FLOCK_OFFSET_LOW  0
  83 #define FLOCK_OFFSET_HIGH 0
  84 #define FLOCK_LENGTH_LOW  0x00000000
  85 #define FLOCK_LENGTH_HIGH 0x80000000
  86
  87   HANDLE hFile;
  88   OVERLAPPED ov;
  89   BOOL rv = FALSE;
  90   DWORD f = 0;
  91
  92   hFile = (HANDLE) _get_osfhandle(fd);
  93   if (hFile == NULL || hFile == INVALID_HANDLE_VALUE) {
  94       _set_errno(EBADF);
  95       return -1;
  96   }
  97
  98   ZeroMemory(&ov, sizeof(ov));
  99   ov.hEvent = NULL;
 100   ov.Offset = FLOCK_OFFSET_LOW;
 101   ov.OffsetHigh = FLOCK_OFFSET_HIGH;
 102
 103   if (operation & LOCK_NB)
 104       f = LOCKFILE_FAIL_IMMEDIATELY;
 105
 106   switch (operation & OP_MASK) {
 107   case LOCK_UN:                 /* Unlock */
 108       rv = UnlockFileEx(hFile, 0,
 109                         FLOCK_LENGTH_LOW, FLOCK_LENGTH_HIGH, &ov);
 110       break;
 111
 112   case LOCK_SH:                 /* Shared lock */
 113       rv = LockFileEx(hFile, f, 0,
 114                       FLOCK_LENGTH_LOW, FLOCK_LENGTH_HIGH, &ov);
 115       break;
 116
 117   case LOCK_EX:                 /* Exclusive lock */
 118       rv = LockFileEx(hFile, f|LOCKFILE_EXCLUSIVE_LOCK, 0,
 119                       FLOCK_LENGTH_LOW, FLOCK_LENGTH_HIGH,
 120                       &ov);
 121       break;
 122
 123   default:
 124       _set_errno(EINVAL);
 125       return -1;
 126   }
 127
 128   if (!rv) {
 129       switch (GetLastError()) {
 130       case ERROR_SHARING_VIOLATION:
 131       case ERROR_LOCK_VIOLATION:
 132       case ERROR_IO_PENDING:
 133           _set_errno(EWOULDBLOCK);
 134           break;
 135
 136       case ERROR_ACCESS_DENIED:
 137           _set_errno(EACCES);
 138           break;
 139
 140       default:
 141           _set_errno(ENOLCK);
 142       }
 143       return -1;
 144   }
 145
 146   return 0;
 147
 148 #else
 149   return -1;
 150 #endif
 151 }
 152
 153 #endif