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>
39 #include <mono/utils/mono-coop-mutex.h>
40 #include <mono/utils/mono-threads.h>
57 BAD_CAPACITY_FOR_FILE_BACKED = 1,
58 CAPACITY_SMALLER_THAN_FILE_SIZE,
63 CAPACITY_MUST_BE_POSITIVE,
69 FILE_MODE_CREATE_NEW = 1,
72 FILE_MODE_OPEN_OR_CREATE = 4,
73 FILE_MODE_TRUNCATE = 5,
78 MMAP_FILE_ACCESS_READ_WRITE = 0,
79 MMAP_FILE_ACCESS_READ = 1,
80 MMAP_FILE_ACCESS_WRITE = 2,
81 MMAP_FILE_ACCESS_COPY_ON_WRITE = 3,
82 MMAP_FILE_ACCESS_READ_EXECUTE = 4,
83 MMAP_FILE_ACCESS_READ_WRITE_EXECUTE = 5,
87 #define DEFAULT_FILEMODE DEFFILEMODE
89 #define DEFAULT_FILEMODE 0666
92 static int mmap_init_state;
93 static MonoCoopMutex named_regions_mutex;
94 static GHashTable *named_regions;
98 align_up_to_page_size (gint64 size)
100 gint64 page_size = mono_pagesize ();
101 return (size + page_size - 1) & ~(page_size - 1);
105 align_down_to_page_size (gint64 size)
107 gint64 page_size = mono_pagesize ();
108 return size & ~(page_size - 1);
112 file_mmap_init (void)
115 switch (mmap_init_state) {
117 if (InterlockedCompareExchange (&mmap_init_state, 1, 0) != 0)
119 named_regions = g_hash_table_new_full (g_str_hash, g_str_equal, NULL, NULL);
120 mono_coop_mutex_init (&named_regions_mutex);
122 mono_atomic_store_release (&mmap_init_state, 2);
127 mono_thread_info_sleep (1, NULL); /* Been init'd by other threads, this is very rare. */
128 } while (mmap_init_state != 2);
133 g_error ("Invalid init state %d", mmap_init_state);
138 named_regions_lock (void)
141 mono_coop_mutex_lock (&named_regions_mutex);
145 named_regions_unlock (void)
147 mono_coop_mutex_unlock (&named_regions_mutex);
152 file_mode_to_unix (int mode)
155 case FILE_MODE_CREATE_NEW:
156 return O_CREAT | O_EXCL;
157 case FILE_MODE_CREATE:
158 return O_CREAT | O_TRUNC;
161 case FILE_MODE_OPEN_OR_CREATE:
163 case FILE_MODE_TRUNCATE:
165 case FILE_MODE_APPEND:
168 g_error ("unknown FileMode %d", mode);
173 access_mode_to_unix (int access)
176 case MMAP_FILE_ACCESS_READ_WRITE:
177 case MMAP_FILE_ACCESS_COPY_ON_WRITE:
178 case MMAP_FILE_ACCESS_READ_WRITE_EXECUTE:
180 case MMAP_FILE_ACCESS_READ:
181 case MMAP_FILE_ACCESS_READ_EXECUTE:
183 case MMAP_FILE_ACCESS_WRITE:
186 g_error ("unknown MemoryMappedFileAccess %d", access);
191 acess_to_mmap_flags (int access)
194 case MMAP_FILE_ACCESS_READ_WRITE:
195 return MONO_MMAP_WRITE | MONO_MMAP_READ | MONO_MMAP_SHARED;
197 case MMAP_FILE_ACCESS_WRITE:
198 return MONO_MMAP_WRITE | MONO_MMAP_SHARED;
200 case MMAP_FILE_ACCESS_COPY_ON_WRITE:
201 return MONO_MMAP_WRITE | MONO_MMAP_READ | MONO_MMAP_PRIVATE;
203 case MMAP_FILE_ACCESS_READ_EXECUTE:
204 return MONO_MMAP_EXEC | MONO_MMAP_PRIVATE | MONO_MMAP_SHARED;
206 case MMAP_FILE_ACCESS_READ_WRITE_EXECUTE:
207 return MONO_MMAP_WRITE | MONO_MMAP_READ | MONO_MMAP_EXEC | MONO_MMAP_SHARED;
209 case MMAP_FILE_ACCESS_READ:
210 return MONO_MMAP_READ | MONO_MMAP_SHARED;
212 g_error ("unknown MemoryMappedFileAccess %d", access);
217 This allow us to special case zero size files that can be arbitrarily mapped.
220 is_special_zero_size_file (struct stat *buf)
222 return buf->st_size == 0 && (buf->st_mode & (S_IFCHR | S_IFBLK | S_IFIFO | S_IFSOCK)) != 0;
226 XXX implement options
229 open_file_map (MonoString *path, int input_fd, int mode, gint64 *capacity, int access, int options, int *error)
232 char *c_path = path ? mono_string_to_utf8 (path) : NULL;
233 MmapHandle *handle = NULL;
237 result = stat (c_path, &buf);
239 result = fstat (input_fd, &buf);
241 if (mode == FILE_MODE_TRUNCATE || mode == FILE_MODE_APPEND || mode == FILE_MODE_OPEN) {
242 if (result == -1) { //XXX translate errno?
243 *error = FILE_NOT_FOUND;
248 if (mode == FILE_MODE_CREATE_NEW && result == 0) {
249 *error = FILE_ALREADY_EXISTS;
254 if (*capacity == 0) {
256 * Special files such as FIFOs, sockets, and devices can have a size of 0. Specifying a capacity for these
257 * also makes little sense, so don't do the check if th file is one of these.
259 if (buf.st_size == 0 && !is_special_zero_size_file (&buf)) {
260 *error = CAPACITY_SMALLER_THAN_FILE_SIZE;
263 *capacity = buf.st_size;
264 } else if (*capacity < buf.st_size) {
265 *error = CAPACITY_SMALLER_THAN_FILE_SIZE;
269 if (mode == FILE_MODE_CREATE_NEW && *capacity == 0) {
270 *error = CAPACITY_SMALLER_THAN_FILE_SIZE;
275 if (path) //FIXME use io portability?
276 fd = open (c_path, file_mode_to_unix (mode) | access_mode_to_unix (access), DEFAULT_FILEMODE);
280 if (fd == -1) { //XXX translate errno?
281 *error = COULD_NOT_OPEN;
285 if (result != 0 || *capacity > buf.st_size) {
286 int unused G_GNUC_UNUSED = ftruncate (fd, (off_t)*capacity);
289 handle = g_new0 (MmapHandle, 1);
290 handle->ref_count = 1;
291 handle->capacity = *capacity;
296 return (void*)handle;
299 #define MONO_ANON_FILE_TEMPLATE "/mono.anonmap.XXXXXXXXX"
301 open_memory_map (MonoString *mapName, int mode, gint64 *capacity, int access, int options, int *error)
305 if (*capacity <= 1) {
306 *error = CAPACITY_MUST_BE_POSITIVE;
310 if (!(mode == FILE_MODE_CREATE_NEW || mode == FILE_MODE_OPEN_OR_CREATE || mode == FILE_MODE_OPEN)) {
311 *error = INVALID_FILE_MODE;
315 c_mapName = mono_string_to_utf8 (mapName);
317 named_regions_lock ();
318 handle = (MmapHandle*)g_hash_table_lookup (named_regions, c_mapName);
320 if (mode == FILE_MODE_CREATE_NEW) {
321 *error = FILE_ALREADY_EXISTS;
326 //XXX should we ftruncate if the file is smaller than capacity?
331 int unused G_GNUC_UNUSED, alloc_size;
333 if (mode == FILE_MODE_OPEN) {
334 *error = FILE_NOT_FOUND;
337 *capacity = align_up_to_page_size (*capacity);
339 tmp_dir = g_get_tmp_dir ();
340 alloc_size = strlen (tmp_dir) + strlen (MONO_ANON_FILE_TEMPLATE) + 1;
341 if (alloc_size > 1024) {//rather fail that stack overflow
342 *error = COULD_NOT_MAP_MEMORY;
345 file_name = (char *)alloca (alloc_size);
346 strcpy (file_name, tmp_dir);
347 strcat (file_name, MONO_ANON_FILE_TEMPLATE);
349 fd = mkstemp (file_name);
351 *error = COULD_NOT_MAP_MEMORY;
356 unused = ftruncate (fd, (off_t)*capacity);
358 handle = g_new0 (MmapHandle, 1);
359 handle->ref_count = 1;
360 handle->capacity = *capacity;
362 handle->name = g_strdup (c_mapName);
364 g_hash_table_insert (named_regions, handle->name, handle);
369 named_regions_unlock ();
377 mono_mmap_open_file (MonoString *path, int mode, MonoString *mapName, gint64 *capacity, int access, int options, int *error)
379 g_assert (path || mapName);
382 return open_file_map (path, -1, mode, capacity, access, options, error);
386 char *c_mapName = mono_string_to_utf8 (mapName);
388 named_regions_lock ();
389 handle = (MmapHandle*)g_hash_table_lookup (named_regions, c_mapName);
391 *error = FILE_ALREADY_EXISTS;
394 handle = (MmapHandle *)open_file_map (path, -1, mode, capacity, access, options, error);
396 handle->name = g_strdup (c_mapName);
397 g_hash_table_insert (named_regions, handle->name, handle);
400 named_regions_unlock ();
406 return open_memory_map (mapName, mode, capacity, access, options, error);
410 mono_mmap_open_handle (void *input_fd, MonoString *mapName, gint64 *capacity, int access, int options, int *error)
414 handle = (MmapHandle *)open_file_map (NULL, GPOINTER_TO_INT (input_fd), FILE_MODE_OPEN, capacity, access, options, error);
416 char *c_mapName = mono_string_to_utf8 (mapName);
418 named_regions_lock ();
419 handle = (MmapHandle*)g_hash_table_lookup (named_regions, c_mapName);
421 *error = FILE_ALREADY_EXISTS;
424 //XXX we're exploiting wapi HANDLE == FD equivalence. THIS IS FRAGILE, create a _wapi_handle_to_fd call
425 handle = (MmapHandle *)open_file_map (NULL, GPOINTER_TO_INT (input_fd), FILE_MODE_OPEN, capacity, access, options, error);
426 handle->name = g_strdup (c_mapName);
427 g_hash_table_insert (named_regions, handle->name, handle);
429 named_regions_unlock ();
437 mono_mmap_close (void *mmap_handle)
439 MmapHandle *handle = (MmapHandle *)mmap_handle;
441 named_regions_lock ();
443 if (handle->ref_count == 0) {
445 g_hash_table_remove (named_regions, handle->name);
447 g_free (handle->name);
451 named_regions_unlock ();
455 mono_mmap_configure_inheritability (void *mmap_handle, gboolean inheritability)
457 MmapHandle *h = (MmapHandle *)mmap_handle;
461 flags = fcntl (fd, F_GETFD, 0);
463 flags &= ~FD_CLOEXEC;
466 fcntl (fd, F_SETFD, flags);
470 mono_mmap_flush (void *mmap_handle)
472 MmapInstance *h = (MmapInstance *)mmap_handle;
475 msync (h->address, h->length, MS_SYNC);
479 mono_mmap_map (void *handle, gint64 offset, gint64 *size, int access, void **mmap_handle, void **base_address)
481 gint64 mmap_offset = 0;
482 MmapHandle *fh = (MmapHandle *)handle;
483 MmapInstance res = { 0 };
484 size_t eff_size = *size;
485 struct stat buf = { 0 };
486 fstat (fh->fd, &buf); //FIXME error handling
488 if (offset > buf.st_size || ((eff_size + offset) > buf.st_size && !is_special_zero_size_file (&buf)))
491 * We use the file size if one of the following conditions is true:
492 * -input size is zero
493 * -input size is bigger than the file and the file is not a magical zero size file such as /dev/mem.
496 eff_size = align_up_to_page_size (buf.st_size) - offset;
499 mmap_offset = align_down_to_page_size (offset);
500 eff_size += (offset - mmap_offset);
501 //FIXME translate some interesting errno values
502 res.address = mono_file_map ((size_t)eff_size, acess_to_mmap_flags (access), fh->fd, mmap_offset, &res.free_handle);
503 res.length = eff_size;
506 *mmap_handle = g_memdup (&res, sizeof (MmapInstance));
507 *base_address = (char*)res.address + (offset - mmap_offset);
513 *base_address = NULL;
514 return COULD_NOT_MAP_MEMORY;
518 mono_mmap_unmap (void *mmap_handle)
521 MmapInstance *h = (MmapInstance *)mmap_handle;
523 res = mono_file_unmap (h->address, h->free_handle);