Create memmap_win32.c for Win32 systems - a mman wrapper

memmap_win32.c

@@ -0,0 +1,173 @@
+#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 */
+    return err;
+}
+
+static DWORD __map_mmap_prot_page(const int prot)
+{
+    DWORD protect = 0;
+    
+    if (prot == PROT_NONE)
+        return 0;
+        
+    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 0;
+        
+    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, off_t off)
+{
+    HANDLE fm, h;
+    
+    void * map = MAP_FAILED;
+    
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable: 4293)
+#endif
+
+    const DWORD dwFileOffsetLow = (sizeof(off_t) <= sizeof(DWORD)) ? 
+                    (DWORD)off : (DWORD)(off & 0xFFFFFFFFL);
+    const DWORD dwFileOffsetHigh = (sizeof(off_t) <= 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 off_t maxSize = off + (off_t)len;
+
+    const DWORD dwMaxSizeLow = (sizeof(off_t) <= sizeof(DWORD)) ? 
+                    (DWORD)maxSize : (DWORD)(maxSize & 0xFFFFFFFFL);
+    const DWORD dwMaxSizeHigh = (sizeof(off_t) <= 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)
+       goto error;
+  
+    map = MapViewOfFile(fm, desiredAccess, dwFileOffsetHigh, dwFileOffsetLow, len);
+
+    CloseHandle(fm);
+  
+    if (!map)
+       goto error;
+
+    return map;
+error:
+    errno = __map_mman_error(GetLastError(), EPERM);
+    return MAP_FAILED;
+}
+
+int munmap(void *addr, size_t len)
+{
+    if (UnmapViewOfFile(addr))
+        return 0;
+        
+    errno =  __map_mman_error(GetLastError(), EPERM);
+    
+    return -1;
+}
+
+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;
+}
+