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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1996, 1997
* Sleepycat Software. All rights reserved.
*/
#include "config.h"
#ifndef lint
static const char sccsid[] = "@(#)db_os_mmap.c 10.4 (Sleepycat) 6/28/97";
#endif /* not lint */
#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>
#include <sys/mman.h>
#include <errno.h>
#endif
#include "db_int.h"
#include "os_ext.h"
/*
* __db_mmap --
* Map in some shared memory backed by a file descriptor.
*
* PUBLIC: int __db_mmap __P((int, size_t, int, int, void *));
*/
int
__db_mmap(fd, len, is_private, rdonly, addr)
int fd, is_private, rdonly;
size_t len;
void *addr;
{
#ifdef _WIN32
/* We have not implemented copy-on-write here */
void * pMemory = 0;
HANDLE hFile = (HANDLE)_get_osfhandle(fd);
HANDLE hMemory = CreateFileMapping(
hFile,
0,
(rdonly ? PAGE_READONLY : PAGE_READWRITE),
0,
len, /* This code fails if the library is ever compiled on a 64-bit machine */
0
);
if (NULL == hMemory)
{
return errno;
}
pMemory = MapViewOfFile(
hMemory,
(rdonly ? FILE_MAP_READ : FILE_MAP_ALL_ACCESS),
0,
0,
len
);
CloseHandle(hMemory);
*(void **)addr = pMemory;
return 0;
#else /* !_WIN32 */
void *p;
int flags, prot;
flags = is_private ? MAP_PRIVATE : MAP_SHARED;
#ifdef MAP_HASSEMAPHORE
flags += MAP_HASSEMAPHORE;
#endif
prot = PROT_READ | (rdonly ? 0 : PROT_WRITE);
#ifndef MAP_FAILED /* XXX: Mmap(2) failure return. */
#define MAP_FAILED -1
#endif
if ((p =
mmap(NULL, len, prot, flags, fd, (off_t)0)) == (void *)MAP_FAILED)
return (errno);
*(void **)addr = p;
return (0);
#endif /* _WIN32 */
}
/*
* __db_unmap --
* Release the specified shared memory.
*
* PUBLIC: int __db_munmap __P((void *, size_t));
*/
int
__db_munmap(addr, len)
void *addr;
size_t len;
{
/*
* !!!
* The argument len is always the same length as was mapped.
*/
#ifdef _WIN32
return (!UnmapViewOfFile(addr) ? errno : 0);
#else
return (munmap(addr, len) ? errno : 0);
#endif
}
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