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mman.cpp
/*
* NOLINT(legal/copyright) - the original authors did not slap a (C) notice in here,
* for whatever reason, and I'm in no position to do that for them.
*
* This file has been included as a part of IsoSpec project, under a MIT licence. It
* comes from the repository:
*
* https://github.com/witwall/mman-win32
*
* which itself is a mirror of:
*
* https://code.google.com/archive/p/mman-win32/
*/
#include "platform.h"
#if ISOSPEC_GOT_MMAN && !ISOSPEC_GOT_SYSTEM_MMAN
#define NOMINMAX
#include <windows.h>
#include <errno.h>
#include <io.h>
#include "mman.h"
#ifndef FILE_MAP_EXECUTE
#define FILE_MAP_EXECUTE 0x0020
#endif /* FILE_MAP_EXECUTE */
static int __map_mman_error(const DWORD err, const int /* deferr */)
{
if (err == 0)
return 0;
// TODO: implement NOLINT(readability/todo) - well, should be assigned to the original authors
return err;
}
static DWORD __map_mmap_prot_page(const int prot)
{
DWORD protect = 0;
if (prot == PROT_NONE)
return protect;
if ((prot & PROT_EXEC) != 0)
{
protect = ((prot & PROT_WRITE) != 0) ?
PAGE_EXECUTE_READWRITE : PAGE_EXECUTE_READ;
}
else
{
protect = ((prot & PROT_WRITE) != 0) ?
PAGE_READWRITE : PAGE_READONLY;
}
return protect;
}
static DWORD __map_mmap_prot_file(const int prot)
{
DWORD desiredAccess = 0;
if (prot == PROT_NONE)
return desiredAccess;
if ((prot & PROT_READ) != 0)
desiredAccess |= FILE_MAP_READ;
if ((prot & PROT_WRITE) != 0)
desiredAccess |= FILE_MAP_WRITE;
if ((prot & PROT_EXEC) != 0)
desiredAccess |= FILE_MAP_EXECUTE;
return desiredAccess;
}
void* mmap(void * /* addr */, size_t len, int prot, int flags, int fildes, OffsetType off)
{
HANDLE fm, h;
void * map = MAP_FAILED;
#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable: 4293)
#endif
const DWORD dwFileOffsetLow = (sizeof(OffsetType) <= sizeof(DWORD)) ?
(DWORD)off : (DWORD)(off & 0xFFFFFFFFL);
const DWORD dwFileOffsetHigh = (sizeof(OffsetType) <= sizeof(DWORD)) ?
(DWORD)0 : (DWORD)((off >> 32) & 0xFFFFFFFFL);
const DWORD protect = __map_mmap_prot_page(prot);
const DWORD desiredAccess = __map_mmap_prot_file(prot);
const OffsetType maxSize = off + (OffsetType)len;
const DWORD dwMaxSizeLow = (sizeof(OffsetType) <= sizeof(DWORD)) ?
(DWORD)maxSize : (DWORD)(maxSize & 0xFFFFFFFFL);
const DWORD dwMaxSizeHigh = (sizeof(OffsetType) <= sizeof(DWORD)) ?
(DWORD)0 : (DWORD)((maxSize >> 32) & 0xFFFFFFFFL);
#ifdef _MSC_VER
#pragma warning(pop)
#endif
errno = 0;
if (len == 0
/* Unsupported flag combinations */
|| (flags & MAP_FIXED) != 0
/* Usupported protection combinations */
|| prot == PROT_EXEC)
{
errno = EINVAL;
return MAP_FAILED;
}
h = ((flags & MAP_ANONYMOUS) == 0) ?
(HANDLE)_get_osfhandle(fildes) : INVALID_HANDLE_VALUE;
if ((flags & MAP_ANONYMOUS) == 0 && h == INVALID_HANDLE_VALUE)
{
errno = EBADF;
return MAP_FAILED;
}
fm = CreateFileMapping(h, NULL, protect, dwMaxSizeHigh, dwMaxSizeLow, NULL);
if (fm == NULL)
{
errno = __map_mman_error(GetLastError(), EPERM);
return MAP_FAILED;
}
map = MapViewOfFile(fm, desiredAccess, dwFileOffsetHigh, dwFileOffsetLow, len);
CloseHandle(fm);
if (map == NULL)
{
errno = __map_mman_error(GetLastError(), EPERM);
return MAP_FAILED;
}
return map;
}
int munmap(void *addr, size_t /* len */)
{
if (UnmapViewOfFile(addr))
return 0;
errno = __map_mman_error(GetLastError(), EPERM);
return -1;
}
#if 0
// Unused by IsoSpec
int _mprotect(void *addr, size_t len, int prot)
{
DWORD newProtect = __map_mmap_prot_page(prot);
DWORD oldProtect = 0;
if (VirtualProtect(addr, len, newProtect, &oldProtect))
return 0;
errno = __map_mman_error(GetLastError(), EPERM);
return -1;
}
int msync(void *addr, size_t len, int /* flags */)
{
if (FlushViewOfFile(addr, len))
return 0;
errno = __map_mman_error(GetLastError(), EPERM);
return -1;
}
int mlock(const void *addr, size_t len)
{
if (VirtualLock((LPVOID)addr, len))
return 0;
errno = __map_mman_error(GetLastError(), EPERM);
return -1;
}
int munlock(const void *addr, size_t len)
{
if (VirtualUnlock((LPVOID)addr, len))
return 0;
errno = __map_mman_error(GetLastError(), EPERM);
return -1;
}
#endif
#endif