2 * file-mmap-posix.c: File mmap internal calls
7 * Copyright 2014 Xamarin Inc (http://www.xamarin.com)
20 #ifdef HAVE_SYS_STAT_H
23 #ifdef HAVE_SYS_TYPES_H
24 #include <sys/types.h>
33 #include <mono/metadata/object.h>
34 #include <mono/metadata/file-io.h>
35 #include <mono/metadata/file-mmap.h>
36 #include <mono/utils/atomic.h>
37 #include <mono/utils/mono-memory-model.h>
38 #include <mono/utils/mono-mmap.h>
55 BAD_CAPACITY_FOR_FILE_BACKED = 1,
56 CAPACITY_SMALLER_THAN_FILE_SIZE,
61 CAPACITY_MUST_BE_POSITIVE,
67 FILE_MODE_CREATE_NEW = 1,
70 FILE_MODE_OPEN_OR_CREATE = 4,
71 FILE_MODE_TRUNCATE = 5,
76 MMAP_FILE_ACCESS_READ_WRITE = 0,
77 MMAP_FILE_ACCESS_READ = 1,
78 MMAP_FILE_ACCESS_WRITE = 2,
79 MMAP_FILE_ACCESS_COPY_ON_WRITE = 3,
80 MMAP_FILE_ACCESS_READ_EXECUTE = 4,
81 MMAP_FILE_ACCESS_READ_WRITE_EXECUTE = 5,
85 #define DEFAULT_FILEMODE DEFFILEMODE
87 #define DEFAULT_FILEMODE 0666
90 static int mmap_init_state;
91 static mono_mutex_t named_regions_mutex;
92 static GHashTable *named_regions;
96 align_up_to_page_size (gint64 size)
98 gint64 page_size = mono_pagesize ();
99 return (size + page_size - 1) & ~(page_size - 1);
103 align_down_to_page_size (gint64 size)
105 gint64 page_size = mono_pagesize ();
106 return size & ~(page_size - 1);
110 file_mmap_init (void)
113 switch (mmap_init_state) {
115 if (InterlockedCompareExchange (&mmap_init_state, 1, 0) != 0)
117 named_regions = g_hash_table_new_full (g_str_hash, g_str_equal, NULL, NULL);
118 mono_mutex_init (&named_regions_mutex);
120 mono_atomic_store_release (&mmap_init_state, 2);
125 g_usleep (1000); /* Been init'd by other threads, this is very rare. */
126 } while (mmap_init_state != 2);
131 g_error ("Invalid init state %d", mmap_init_state);
136 named_regions_lock (void)
139 mono_mutex_lock (&named_regions_mutex);
143 named_regions_unlock (void)
145 mono_mutex_unlock (&named_regions_mutex);
150 file_mode_to_unix (int mode)
153 case FILE_MODE_CREATE_NEW:
154 return O_CREAT | O_EXCL;
155 case FILE_MODE_CREATE:
156 return O_CREAT | O_TRUNC;
159 case FILE_MODE_OPEN_OR_CREATE:
161 case FILE_MODE_TRUNCATE:
163 case FILE_MODE_APPEND:
166 g_error ("unknown FileMode %d", mode);
171 access_mode_to_unix (int access)
174 case MMAP_FILE_ACCESS_READ_WRITE:
175 case MMAP_FILE_ACCESS_COPY_ON_WRITE:
176 case MMAP_FILE_ACCESS_READ_WRITE_EXECUTE:
178 case MMAP_FILE_ACCESS_READ:
179 case MMAP_FILE_ACCESS_READ_EXECUTE:
181 case MMAP_FILE_ACCESS_WRITE:
184 g_error ("unknown MemoryMappedFileAccess %d", access);
189 acess_to_mmap_flags (int access)
192 case MMAP_FILE_ACCESS_READ_WRITE:
193 return MONO_MMAP_WRITE | MONO_MMAP_READ | MONO_MMAP_SHARED;
195 case MMAP_FILE_ACCESS_WRITE:
196 return MONO_MMAP_WRITE | MONO_MMAP_SHARED;
198 case MMAP_FILE_ACCESS_COPY_ON_WRITE:
199 return MONO_MMAP_WRITE | MONO_MMAP_READ | MONO_MMAP_PRIVATE;
201 case MMAP_FILE_ACCESS_READ_EXECUTE:
202 return MONO_MMAP_EXEC | MONO_MMAP_PRIVATE | MONO_MMAP_SHARED;
204 case MMAP_FILE_ACCESS_READ_WRITE_EXECUTE:
205 return MONO_MMAP_WRITE | MONO_MMAP_READ | MONO_MMAP_EXEC | MONO_MMAP_SHARED;
207 case MMAP_FILE_ACCESS_READ:
208 return MONO_MMAP_READ | MONO_MMAP_SHARED;
210 g_error ("unknown MemoryMappedFileAccess %d", access);
215 This allow us to special case zero size files that can be arbitrarily mapped.
218 is_special_zero_size_file (struct stat *buf)
220 return buf->st_size == 0 && (buf->st_mode & (S_IFCHR | S_IFBLK | S_IFIFO | S_IFSOCK)) != 0;
224 XXX implement options
227 open_file_map (MonoString *path, int input_fd, int mode, gint64 *capacity, int access, int options, int *error)
230 char *c_path = path ? mono_string_to_utf8 (path) : NULL;
231 MmapHandle *handle = NULL;
235 result = stat (c_path, &buf);
237 result = fstat (input_fd, &buf);
239 if (mode == FILE_MODE_TRUNCATE || mode == FILE_MODE_APPEND || mode == FILE_MODE_OPEN) {
240 if (result == -1) { //XXX translate errno?
241 *error = FILE_NOT_FOUND;
246 if (mode == FILE_MODE_CREATE_NEW && result == 0) {
247 *error = FILE_ALREADY_EXISTS;
252 if (*capacity == 0) {
254 * Special files such as FIFOs, sockets, and devices can have a size of 0. Specifying a capacity for these
255 * also makes little sense, so don't do the check if th file is one of these.
257 if (buf.st_size == 0 && !is_special_zero_size_file (&buf)) {
258 *error = CAPACITY_SMALLER_THAN_FILE_SIZE;
261 *capacity = buf.st_size;
262 } else if (*capacity < buf.st_size) {
263 *error = CAPACITY_SMALLER_THAN_FILE_SIZE;
267 if (mode == FILE_MODE_CREATE_NEW && *capacity == 0) {
268 *error = CAPACITY_SMALLER_THAN_FILE_SIZE;
273 if (path) //FIXME use io portability?
274 fd = open (c_path, file_mode_to_unix (mode) | access_mode_to_unix (access), DEFAULT_FILEMODE);
278 if (fd == -1) { //XXX translate errno?
279 *error = COULD_NOT_OPEN;
283 if (result != 0 || *capacity > buf.st_size) {
284 int unused G_GNUC_UNUSED = ftruncate (fd, (off_t)*capacity);
287 handle = g_new0 (MmapHandle, 1);
288 handle->ref_count = 1;
289 handle->capacity = *capacity;
294 return (void*)handle;
297 #define MONO_ANON_FILE_TEMPLATE "/mono.anonmap.XXXXXXXXX"
299 open_memory_map (MonoString *mapName, int mode, gint64 *capacity, int access, int options, int *error)
303 if (*capacity <= 1) {
304 *error = CAPACITY_MUST_BE_POSITIVE;
308 if (!(mode == FILE_MODE_CREATE_NEW || mode == FILE_MODE_OPEN_OR_CREATE || mode == FILE_MODE_OPEN)) {
309 *error = INVALID_FILE_MODE;
313 c_mapName = mono_string_to_utf8 (mapName);
315 named_regions_lock ();
316 handle = (MmapHandle*)g_hash_table_lookup (named_regions, c_mapName);
318 if (mode == FILE_MODE_CREATE_NEW) {
319 *error = FILE_ALREADY_EXISTS;
324 //XXX should we ftruncate if the file is smaller than capacity?
329 int unused G_GNUC_UNUSED, alloc_size;
331 if (mode == FILE_MODE_OPEN) {
332 *error = FILE_NOT_FOUND;
335 *capacity = align_up_to_page_size (*capacity);
337 tmp_dir = g_get_tmp_dir ();
338 alloc_size = strlen (tmp_dir) + strlen (MONO_ANON_FILE_TEMPLATE) + 1;
339 if (alloc_size > 1024) {//rather fail that stack overflow
340 *error = COULD_NOT_MAP_MEMORY;
343 file_name = alloca (alloc_size);
344 strcpy (file_name, tmp_dir);
345 strcat (file_name, MONO_ANON_FILE_TEMPLATE);
347 fd = mkstemp (file_name);
349 *error = COULD_NOT_MAP_MEMORY;
354 unused = ftruncate (fd, (off_t)*capacity);
356 handle = g_new0 (MmapHandle, 1);
357 handle->ref_count = 1;
358 handle->capacity = *capacity;
360 handle->name = g_strdup (c_mapName);
362 g_hash_table_insert (named_regions, handle->name, handle);
367 named_regions_unlock ();
375 mono_mmap_open_file (MonoString *path, int mode, MonoString *mapName, gint64 *capacity, int access, int options, int *error)
377 g_assert (path || mapName);
380 return open_file_map (path, -1, mode, capacity, access, options, error);
384 char *c_mapName = mono_string_to_utf8 (mapName);
386 named_regions_lock ();
387 handle = (MmapHandle*)g_hash_table_lookup (named_regions, c_mapName);
389 *error = FILE_ALREADY_EXISTS;
392 handle = open_file_map (path, -1, mode, capacity, access, options, error);
394 handle->name = g_strdup (c_mapName);
395 g_hash_table_insert (named_regions, handle->name, handle);
398 named_regions_unlock ();
404 return open_memory_map (mapName, mode, capacity, access, options, error);
408 mono_mmap_open_handle (void *input_fd, MonoString *mapName, gint64 *capacity, int access, int options, int *error)
411 char *c_mapName = mono_string_to_utf8 (mapName);
413 named_regions_lock ();
414 handle = (MmapHandle*)g_hash_table_lookup (named_regions, c_mapName);
416 *error = FILE_ALREADY_EXISTS;
419 //XXX we're exploiting wapi HANDLE == FD equivalence. THIS IS FRAGILE, create a _wapi_handle_to_fd call
420 handle = open_file_map (NULL, GPOINTER_TO_INT (input_fd), FILE_MODE_OPEN, capacity, access, options, error);
421 handle->name = g_strdup (c_mapName);
422 g_hash_table_insert (named_regions, handle->name, handle);
424 named_regions_unlock ();
431 mono_mmap_close (void *mmap_handle)
433 MmapHandle *handle = mmap_handle;
435 named_regions_lock ();
437 if (handle->ref_count == 0) {
439 g_hash_table_remove (named_regions, handle->name);
441 g_free (handle->name);
445 named_regions_unlock ();
449 mono_mmap_configure_inheritability (void *mmap_handle, gboolean inheritability)
451 MmapHandle *h = mmap_handle;
455 flags = fcntl (fd, F_GETFD, 0);
457 flags &= ~FD_CLOEXEC;
460 fcntl (fd, F_SETFD, flags);
464 mono_mmap_flush (void *mmap_handle)
466 MmapInstance *h = mmap_handle;
469 msync (h->address, h->length, MS_SYNC);
473 mono_mmap_map (void *handle, gint64 offset, gint64 *size, int access, void **mmap_handle, void **base_address)
475 gint64 mmap_offset = 0;
476 MmapHandle *fh = handle;
477 MmapInstance res = { 0 };
478 size_t eff_size = *size;
479 struct stat buf = { 0 };
480 fstat (fh->fd, &buf); //FIXME error handling
482 if (offset > buf.st_size || ((eff_size + offset) > buf.st_size && !is_special_zero_size_file (&buf)))
485 * We use the file size if one of the following conditions is true:
486 * -input size is zero
487 * -input size is bigger than the file and the file is not a magical zero size file such as /dev/mem.
490 eff_size = align_up_to_page_size (buf.st_size) - offset;
493 mmap_offset = align_down_to_page_size (offset);
494 eff_size += (offset - mmap_offset);
495 //FIXME translate some interesting errno values
496 res.address = mono_file_map ((size_t)eff_size, acess_to_mmap_flags (access), fh->fd, mmap_offset, &res.free_handle);
497 res.length = eff_size;
500 *mmap_handle = g_memdup (&res, sizeof (MmapInstance));
501 *base_address = (char*)res.address + (offset - mmap_offset);
507 *base_address = NULL;
508 return COULD_NOT_MAP_MEMORY;
512 mono_mmap_unmap (void *mmap_handle)
515 MmapInstance *h = mmap_handle;
517 res = mono_file_unmap (h->address, h->free_handle);