summaryrefslogtreecommitdiff
path: root/mysys/my_mmap.c
blob: cde09c4a28ef56c9aabfacc74e4fc4d57abff2d9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
/* Copyright (c) 2000-2006 MySQL AB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#include "mysys_priv.h"

#ifdef HAVE_SYS_MMAN_H

/*
  system msync() only syncs mmap'ed area to fs cache.
  fsync() is required to really sync to disc
*/
int my_msync(int fd, void *addr, size_t len, int flags)
{
  msync(addr, len, flags);
  return my_sync(fd, MYF(0));
}

#elif defined(__WIN__)

static SECURITY_ATTRIBUTES mmap_security_attributes=
  {sizeof(SECURITY_ATTRIBUTES), 0, TRUE};

void *my_mmap(void *addr, size_t len, int prot,
               int flags, int fd, my_off_t offset)
{
  HANDLE hFileMap;
  LPVOID ptr;
  HANDLE hFile= (HANDLE)_get_osfhandle(fd);
  if (hFile == INVALID_HANDLE_VALUE)
    return MAP_FAILED;

  hFileMap=CreateFileMapping(hFile, &mmap_security_attributes,
                             PAGE_READWRITE, 0, (DWORD) len, NULL);
  if (hFileMap == 0)
    return MAP_FAILED;

  ptr=MapViewOfFile(hFileMap,
                    prot & PROT_WRITE ? FILE_MAP_WRITE : FILE_MAP_READ,
                    (DWORD)(offset >> 32), (DWORD)offset, len);

  /*
    MSDN explicitly states that it's possible to close File Mapping Object
    even when a view is not unmapped - then the object will be held open
    implicitly until unmap, as every view stores internally a handler of
    a corresponding File Mapping Object
   */
  CloseHandle(hFileMap);

  if (ptr)
    return ptr;

  return MAP_FAILED;
}

int my_munmap(void *addr, size_t len)
{
  return UnmapViewOfFile(addr) ? 0 : -1;
}

int my_msync(int fd, void *addr, size_t len, int flags)
{
  return FlushViewOfFile(addr, len) ? 0 : -1;
}

#else
#warning "no mmap!"
#endif