2 * file-mmap-windows.c: MemoryMappedFile internal calls for Windows
4 * Copyright 2016 Microsoft
5 * Licensed under the MIT license. See LICENSE file in the project root for full license information.
9 * The code in this file has been inspired by the CoreFX MemoryMappedFile Windows implementation contained in the files
11 * https://github.com/dotnet/corefx/blob/master/src/System.IO.MemoryMappedFiles/src/System/IO/MemoryMappedFiles/MemoryMappedFile.Windows.cs
12 * https://github.com/dotnet/corefx/blob/master/src/System.IO.MemoryMappedFiles/src/System/IO/MemoryMappedFiles/MemoryMappedView.Windows.cs
21 #include <mono/metadata/file-mmap.h>
23 // These control the retry behaviour when lock violation errors occur during Flush:
24 #define MAX_FLUSH_WAITS 15 // must be <=30
25 #define MAX_FLUSH_RETIRES_PER_WAIT 20
33 BAD_CAPACITY_FOR_FILE_BACKED = 1,
34 CAPACITY_SMALLER_THAN_FILE_SIZE,
39 CAPACITY_MUST_BE_POSITIVE,
43 CAPACITY_LARGER_THAN_LOGICAL_ADDRESS_SPACE
47 FILE_MODE_CREATE_NEW = 1,
50 FILE_MODE_OPEN_OR_CREATE = 4,
51 FILE_MODE_TRUNCATE = 5,
56 MMAP_FILE_ACCESS_READ_WRITE = 0,
57 MMAP_FILE_ACCESS_READ = 1,
58 MMAP_FILE_ACCESS_WRITE = 2,
59 MMAP_FILE_ACCESS_COPY_ON_WRITE = 3,
60 MMAP_FILE_ACCESS_READ_EXECUTE = 4,
61 MMAP_FILE_ACCESS_READ_WRITE_EXECUTE = 5,
64 static DWORD get_page_access (int access)
67 case MMAP_FILE_ACCESS_READ:
69 case MMAP_FILE_ACCESS_READ_WRITE:
70 return PAGE_READWRITE;
71 case MMAP_FILE_ACCESS_COPY_ON_WRITE:
72 return PAGE_WRITECOPY;
73 case MMAP_FILE_ACCESS_READ_EXECUTE:
74 return PAGE_EXECUTE_READ;
75 case MMAP_FILE_ACCESS_READ_WRITE_EXECUTE:
76 return PAGE_EXECUTE_READWRITE;
78 g_error ("unknown MemoryMappedFileAccess %d", access);
82 static DWORD get_file_access (int access)
85 case MMAP_FILE_ACCESS_READ:
86 case MMAP_FILE_ACCESS_READ_EXECUTE:
88 case MMAP_FILE_ACCESS_READ_WRITE:
89 case MMAP_FILE_ACCESS_COPY_ON_WRITE:
90 case MMAP_FILE_ACCESS_READ_WRITE_EXECUTE:
91 return GENERIC_READ | GENERIC_WRITE;
92 case MMAP_FILE_ACCESS_WRITE:
95 g_error ("unknown MemoryMappedFileAccess %d", access);
99 static int get_file_map_access (int access)
102 case MMAP_FILE_ACCESS_READ:
103 return FILE_MAP_READ;
104 case MMAP_FILE_ACCESS_WRITE:
105 return FILE_MAP_WRITE;
106 case MMAP_FILE_ACCESS_READ_WRITE:
107 return FILE_MAP_READ | FILE_MAP_WRITE;
108 case MMAP_FILE_ACCESS_COPY_ON_WRITE:
109 return FILE_MAP_COPY;
110 case MMAP_FILE_ACCESS_READ_EXECUTE:
111 return FILE_MAP_EXECUTE | FILE_MAP_READ;
112 case MMAP_FILE_ACCESS_READ_WRITE_EXECUTE:
113 return FILE_MAP_EXECUTE | FILE_MAP_READ | FILE_MAP_WRITE;
115 g_error ("unknown MemoryMappedFileAccess %d", access);
119 static int convert_win32_error (int error, int def)
122 case ERROR_FILE_NOT_FOUND:
123 return FILE_NOT_FOUND;
124 case ERROR_FILE_EXISTS:
125 case ERROR_ALREADY_EXISTS:
126 return FILE_ALREADY_EXISTS;
127 case ERROR_ACCESS_DENIED:
128 return ACCESS_DENIED;
133 static void *open_handle (void *handle, MonoString *mapName, int mode, gint64 *capacity, int access, int options, int *error)
135 g_assert (handle != NULL);
137 wchar_t *w_mapName = NULL;
138 HANDLE result = NULL;
140 if (handle == INVALID_HANDLE_VALUE) {
141 if (*capacity <= 0) {
142 *error = CAPACITY_MUST_BE_POSITIVE;
145 #if SIZEOF_VOID_P == 4
146 if (*capacity > UINT32_MAX) {
147 *error = CAPACITY_LARGER_THAN_LOGICAL_ADDRESS_SPACE;
151 if (!(mode == FILE_MODE_CREATE_NEW || mode == FILE_MODE_OPEN_OR_CREATE || mode == FILE_MODE_OPEN)) {
152 *error = INVALID_FILE_MODE;
156 FILE_STANDARD_INFO info;
157 if (!GetFileInformationByHandleEx ((HANDLE) handle, FileStandardInfo, &info, sizeof (FILE_STANDARD_INFO))) {
158 *error = convert_win32_error (GetLastError (), COULD_NOT_OPEN);
161 if (*capacity == 0) {
162 if (info.EndOfFile.QuadPart == 0) {
163 *error = CAPACITY_SMALLER_THAN_FILE_SIZE;
166 } else if (*capacity < info.EndOfFile.QuadPart) {
167 *error = CAPACITY_SMALLER_THAN_FILE_SIZE;
172 w_mapName = mapName ? mono_string_to_utf16 (mapName) : NULL;
174 if (mode == FILE_MODE_CREATE_NEW || handle != INVALID_HANDLE_VALUE) {
175 result = CreateFileMappingW ((HANDLE)handle, NULL, get_page_access (access) | options, (DWORD)(((guint64)*capacity) >> 32), (DWORD)*capacity, w_mapName);
176 if (result && GetLastError () == ERROR_ALREADY_EXISTS) {
177 CloseHandle (result);
179 *error = FILE_ALREADY_EXISTS;
180 } else if (!result && GetLastError () != NO_ERROR) {
181 *error = convert_win32_error (GetLastError (), COULD_NOT_OPEN);
183 } else if (mode == FILE_MODE_OPEN || mode == FILE_MODE_OPEN_OR_CREATE && access == MMAP_FILE_ACCESS_WRITE) {
184 result = OpenFileMappingW (get_file_map_access (access), FALSE, w_mapName);
186 if (mode == FILE_MODE_OPEN_OR_CREATE && GetLastError () == ERROR_FILE_NOT_FOUND) {
187 *error = INVALID_FILE_MODE;
189 *error = convert_win32_error (GetLastError (), COULD_NOT_OPEN);
192 } else if (mode == FILE_MODE_OPEN_OR_CREATE) {
194 // This replicates how CoreFX does MemoryMappedFile.CreateOrOpen ().
196 /// Try to open the file if it exists -- this requires a bit more work. Loop until we can
197 /// either create or open a memory mapped file up to a timeout. CreateFileMapping may fail
198 /// if the file exists and we have non-null security attributes, in which case we need to
199 /// use OpenFileMapping. But, there exists a race condition because the memory mapped file
200 /// may have closed between the two calls -- hence the loop.
202 /// The retry/timeout logic increases the wait time each pass through the loop and times
203 /// out in approximately 1.4 minutes. If after retrying, a MMF handle still hasn't been opened,
204 /// throw an InvalidOperationException.
206 guint32 waitRetries = 14; //((2^13)-1)*10ms == approximately 1.4mins
207 guint32 waitSleep = 0;
209 while (waitRetries > 0) {
210 result = CreateFileMappingW ((HANDLE)handle, NULL, get_page_access (access) | options, (DWORD)(((guint64)*capacity) >> 32), (DWORD)*capacity, w_mapName);
213 if (GetLastError() != ERROR_ACCESS_DENIED) {
214 *error = convert_win32_error (GetLastError (), COULD_NOT_OPEN);
217 result = OpenFileMappingW (get_file_map_access (access), FALSE, w_mapName);
220 if (GetLastError () != ERROR_FILE_NOT_FOUND) {
221 *error = convert_win32_error (GetLastError (), COULD_NOT_OPEN);
224 // increase wait time
226 if (waitSleep == 0) {
229 mono_thread_info_sleep (waitSleep, NULL);
235 *error = COULD_NOT_OPEN;
244 void *mono_mmap_open_file (MonoString *path, int mode, MonoString *mapName, gint64 *capacity, int access, int options, int *error)
246 g_assert (path != NULL || mapName != NULL);
248 wchar_t *w_path = NULL;
249 HANDLE hFile = INVALID_HANDLE_VALUE;
250 HANDLE result = NULL;
251 gboolean delete_on_error = FALSE;
254 w_path = mono_string_to_utf16 (path);
255 WIN32_FILE_ATTRIBUTE_DATA file_attrs;
256 gboolean existed = GetFileAttributesExW (w_path, GetFileExInfoStandard, &file_attrs);
257 if (!existed && mode == FILE_MODE_CREATE_NEW && *capacity == 0) {
258 *error = CAPACITY_SMALLER_THAN_FILE_SIZE;
261 hFile = CreateFileW (w_path, get_file_access (access), FILE_SHARE_READ, NULL, mode, FILE_ATTRIBUTE_NORMAL, NULL);
262 if (hFile == INVALID_HANDLE_VALUE) {
263 *error = convert_win32_error (GetLastError (), COULD_NOT_OPEN);
266 delete_on_error = !existed;
269 result = open_handle (hFile, mapName, mode, capacity, access, options, error);
272 if (!result && delete_on_error)
273 DeleteFileW (w_path);
280 void *mono_mmap_open_handle (void *handle, MonoString *mapName, gint64 *capacity, int access, int options, int *error)
282 g_assert (handle != NULL);
284 return open_handle (handle, mapName, FILE_MODE_OPEN, capacity, access, options, error);
287 void mono_mmap_close (void *mmap_handle)
289 g_assert (mmap_handle);
290 CloseHandle ((HANDLE) mmap_handle);
293 void mono_mmap_configure_inheritability (void *mmap_handle, gboolean inheritability)
295 g_assert (mmap_handle);
296 if (!SetHandleInformation ((HANDLE) mmap_handle, HANDLE_FLAG_INHERIT, inheritability ? HANDLE_FLAG_INHERIT : 0)) {
297 g_error ("mono_mmap_configure_inheritability: SetHandleInformation failed with error %d!", GetLastError ());
301 void mono_mmap_flush (void *mmap_handle)
303 g_assert (mmap_handle);
304 MmapInstance *h = (MmapInstance *)mmap_handle;
306 if (FlushViewOfFile (h->address, h->length))
309 // This replicates how CoreFX does MemoryMappedView.Flush ().
311 // It is a known issue within the NTFS transaction log system that
312 // causes FlushViewOfFile to intermittently fail with ERROR_LOCK_VIOLATION
313 // As a workaround, we catch this particular error and retry the flush operation
314 // a few milliseconds later. If it does not work, we give it a few more tries with
315 // increasing intervals. Eventually, however, we need to give up. In ad-hoc tests
316 // this strategy successfully flushed the view after no more than 3 retries.
318 if (GetLastError () != ERROR_LOCK_VIOLATION)
319 // TODO: Propagate error to caller
322 for (int w = 0; w < MAX_FLUSH_WAITS; w++) {
323 int pause = (1 << w); // MaxFlushRetries should never be over 30
324 mono_thread_info_sleep (pause, NULL);
326 for (int r = 0; r < MAX_FLUSH_RETIRES_PER_WAIT; r++) {
327 if (FlushViewOfFile (h->address, h->length))
330 if (GetLastError () != ERROR_LOCK_VIOLATION)
331 // TODO: Propagate error to caller
334 mono_thread_info_yield ();
338 // We got to here, so there was no success:
339 // TODO: Propagate error to caller
342 int mono_mmap_map (void *handle, gint64 offset, gint64 *size, int access, void **mmap_handle, void **base_address)
344 static DWORD allocationGranularity = 0;
345 if (allocationGranularity == 0) {
347 GetSystemInfo (&info);
348 allocationGranularity = info.dwAllocationGranularity;
351 gint64 extraMemNeeded = offset % allocationGranularity;
352 guint64 newOffset = offset - extraMemNeeded;
353 gint64 nativeSize = (*size != 0) ? *size + extraMemNeeded : 0;
355 #if SIZEOF_VOID_P == 4
356 if (nativeSize > UINT32_MAX)
357 return CAPACITY_LARGER_THAN_LOGICAL_ADDRESS_SPACE;
360 void *address = MapViewOfFile ((HANDLE) handle, get_file_map_access (access), (DWORD) (newOffset >> 32), (DWORD) newOffset, (SIZE_T) nativeSize);
362 return convert_win32_error (GetLastError (), COULD_NOT_MAP_MEMORY);
364 // Query the view for its size and allocation type
365 MEMORY_BASIC_INFORMATION viewInfo;
366 VirtualQuery (address, &viewInfo, sizeof (MEMORY_BASIC_INFORMATION));
367 guint64 viewSize = (guint64) viewInfo.RegionSize;
369 // Allocate the pages if we were using the MemoryMappedFileOptions.DelayAllocatePages option
370 // OR check if the allocated view size is smaller than the expected native size
371 // If multiple overlapping views are created over the file mapping object, the pages in a given region
372 // could have different attributes(MEM_RESERVE OR MEM_COMMIT) as MapViewOfFile preserves coherence between
373 // views created on a mapping object backed by same file.
374 // In which case, the viewSize will be smaller than nativeSize required and viewState could be MEM_COMMIT
375 // but more pages may need to be committed in the region.
376 // This is because, VirtualQuery function(that internally invokes VirtualQueryEx function) returns the attributes
377 // and size of the region of pages with matching attributes starting from base address.
378 // VirtualQueryEx: http://msdn.microsoft.com/en-us/library/windows/desktop/aa366907(v=vs.85).aspx
379 if (((viewInfo.State & MEM_RESERVE) != 0) || viewSize < (guint64) nativeSize) {
380 void *tempAddress = VirtualAlloc (address, nativeSize != 0 ? nativeSize : viewSize, MEM_COMMIT, get_page_access (access));
382 return convert_win32_error (GetLastError (), COULD_NOT_MAP_MEMORY);
384 // again query the view for its new size
385 VirtualQuery (address, &viewInfo, sizeof (MEMORY_BASIC_INFORMATION));
386 viewSize = (guint64) viewInfo.RegionSize;
390 *size = viewSize - extraMemNeeded;
392 MmapInstance *h = g_malloc0 (sizeof (MmapInstance));
393 h->address = address;
394 h->length = *size + extraMemNeeded;
396 *base_address = (char*) address + (offset - newOffset);
401 gboolean mono_mmap_unmap (void *mmap_handle)
403 g_assert (mmap_handle);
405 MmapInstance *h = (MmapInstance *) mmap_handle;
407 gboolean result = UnmapViewOfFile (h->address);