85 lines
2.1 KiB
C
85 lines
2.1 KiB
C
/* mmap() replacement for Windows
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*
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* Author: Mike Frysinger <vapier@gentoo.org>
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* Placed into the public domain
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*/
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/* References:
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* CreateFileMapping: http://msdn.microsoft.com/en-us/library/aa366537(VS.85).aspx
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* CloseHandle: http://msdn.microsoft.com/en-us/library/ms724211(VS.85).aspx
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* MapViewOfFile: http://msdn.microsoft.com/en-us/library/aa366761(VS.85).aspx
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* UnmapViewOfFile: http://msdn.microsoft.com/en-us/library/aa366882(VS.85).aspx
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*/
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#include <io.h>
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#include <windows.h>
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#include "mmap.h"
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#ifdef __USE_FILE_OFFSET64
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# define DWORD_HI(x) (x >> 32)
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# define DWORD_LO(x) ((x) & 0xffffffff)
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#else
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# define DWORD_HI(x) (0)
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# define DWORD_LO(x) (x)
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#endif
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void* mmap(void* start, size_t length, int prot, int flags, int fd, off_t offset)
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{
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if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC))
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return MAP_FAILED;
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if (fd == -1) {
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if (!(flags & MAP_ANON) || offset)
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return MAP_FAILED;
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} else if (flags & MAP_ANON)
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return MAP_FAILED;
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DWORD flProtect;
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if (prot & PROT_WRITE) {
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if (prot & PROT_EXEC)
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flProtect = PAGE_EXECUTE_READWRITE;
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else
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flProtect = PAGE_READWRITE;
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} else if (prot & PROT_EXEC) {
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if (prot & PROT_READ)
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flProtect = PAGE_EXECUTE_READ;
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else if (prot & PROT_EXEC)
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flProtect = PAGE_EXECUTE;
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} else
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flProtect = PAGE_READONLY;
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off_t end = length + offset;
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HANDLE mmap_fd, h;
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if (fd == -1)
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mmap_fd = INVALID_HANDLE_VALUE;
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else
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mmap_fd = (HANDLE)_get_osfhandle(fd);
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h = CreateFileMapping(mmap_fd, NULL, flProtect, DWORD_HI(end), DWORD_LO(end), NULL);
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if (h == NULL)
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return MAP_FAILED;
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DWORD dwDesiredAccess;
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if (prot & PROT_WRITE)
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dwDesiredAccess = FILE_MAP_WRITE;
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else
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dwDesiredAccess = FILE_MAP_READ;
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if (prot & PROT_EXEC)
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dwDesiredAccess |= FILE_MAP_EXECUTE;
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if (flags & MAP_PRIVATE)
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dwDesiredAccess |= FILE_MAP_COPY;
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void *ret = MapViewOfFile(h, dwDesiredAccess, DWORD_HI(offset), DWORD_LO(offset), length);
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if (ret == NULL) {
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ret = MAP_FAILED;
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}
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// since we are handling the file ourselves with fd, close the Windows Handle here
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CloseHandle(h);
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return ret;
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}
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void munmap(void* addr, size_t length)
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{
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UnmapViewOfFile(addr);
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}
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#undef DWORD_HI
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#undef DWORD_LO
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