mono/metadata/file-mmap-posix.c

   1 /*
   2  * file-mmap-posix.c: File mmap internal calls
   3  *
   4  * Author:
   5  *      Rodrigo Kumpera
   6  *
   7  * Copyright 2014 Xamarin Inc (http://www.xamarin.com)
   8  */
   9
  10 #include <config.h>
  11
  12 #ifndef TARGET_WIN32
  13
  14 #include <glib.h>
  15 #include <string.h>
  16 #include <errno.h>
  17 #ifdef HAVE_UNISTD_H
  18 #include <unistd.h>
  19 #endif
  20 #ifdef HAVE_SYS_STAT_H
  21 #include <sys/stat.h>
  22 #endif
  23 #ifdef HAVE_SYS_TYPES_H
  24 #include <sys/types.h>
  25 #endif
  26 #if HAVE_SYS_MMAN_H
  27 #include <sys/mman.h>
  28 #endif
  29
  30 #include <fcntl.h>
  31
  32
  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
  40 enum {
  41         MMAP_KIND_FILE = 1,
  42         MMAP_KIND_MEMORY = 2
  43 };
  44
  45 typedef struct {
  46         int kind;
  47         int ref_count;
  48         gint64 capacity;
  49         char *name;
  50 } Handle;
  51
  52 typedef struct {
  53         Handle handle;
  54         int fd;
  55 } FileHandle;
  56
  57 typedef struct {
  58         Handle handle;
  59         void *address;
  60         size_t length;
  61 } MemoryHandle;
  62
  63 typedef struct {
  64         void *address;
  65         void *free_handle;
  66         int kind;
  67         size_t length;
  68 } MmapHandle;
  69
  70 enum {
  71         BAD_CAPACITY_FOR_FILE_BACKED = 1,
  72         CAPACITY_SMALLER_THAN_FILE_SIZE,
  73         FILE_NOT_FOUND,
  74         FILE_ALREADY_EXISTS,
  75         PATH_TOO_LONG,
  76         COULD_NOT_OPEN,
  77         CAPACITY_MUST_BE_POSITIVE,
  78         INVALID_FILE_MODE,
  79         COULD_NOT_MAP_MEMORY
  80 };
  81
  82 enum {
  83         FILE_MODE_CREATE_NEW = 1,
  84         FILE_MODE_CREATE = 2,
  85         FILE_MODE_OPEN = 3,
  86         FILE_MODE_OPEN_OR_CREATE = 4,
  87         FILE_MODE_TRUNCATE = 5,
  88         FILE_MODE_APPEND = 6,
  89 };
  90
  91 enum {
  92         MMAP_FILE_ACCESS_READ_WRITE = 0,
  93         MMAP_FILE_ACCESS_READ = 1,
  94         MMAP_FILE_ACCESS_WRITE = 2,
  95         MMAP_FILE_ACCESS_COPY_ON_WRITE = 3,
  96         MMAP_FILE_ACCESS_READ_EXECUTE = 4,
  97         MMAP_FILE_ACCESS_READ_WRITE_EXECUTE = 5,
  98 };
  99
 100
 101 static int mmap_init_state;
 102 static mono_mutex_t named_regions_mutex;
 103 static GHashTable *named_regions;
 104
 105
 106 static gint64
 107 align_up_to_page_size (gint64 size)
 108 {
 109         gint64 page_size = mono_pagesize ();
 110         return (size + page_size - 1) & ~(page_size - 1);
 111 }
 112
 113 static gint64
 114 align_down_to_page_size (gint64 size)
 115 {
 116         gint64 page_size = mono_pagesize ();
 117         return size & ~(page_size - 1);
 118 }
 119
 120 static void
 121 file_mmap_init (void)
 122 {
 123 retry:
 124         switch (mmap_init_state) {
 125         case  0:
 126                 if (InterlockedCompareExchange (&mmap_init_state, 1, 0) != 0)
 127                         goto retry;
 128                 named_regions = g_hash_table_new_full (g_str_hash, g_str_equal, NULL, NULL);
 129                 mono_mutex_init (&named_regions_mutex);
 130
 131                 mono_atomic_store_release (&mmap_init_state, 2);
 132                 break;
 133
 134         case 1:
 135                 do {
 136                         g_usleep (1000); /* Been init'd by other threads, this is very rare. */
 137                 } while (mmap_init_state != 2);
 138                 break;
 139         case 2:
 140                 break;
 141         default:
 142                 g_error ("Invalid init state %d", mmap_init_state);
 143         }
 144 }
 145
 146 static void
 147 named_regions_lock (void)
 148 {
 149         file_mmap_init ();
 150         mono_mutex_lock (&named_regions_mutex);
 151 }
 152
 153 static void
 154 named_regions_unlock (void)
 155 {
 156         mono_mutex_unlock (&named_regions_mutex);
 157 }
 158
 159
 160 static int
 161 file_mode_to_unix (int mode)
 162 {
 163         switch (mode) {
 164         case FILE_MODE_CREATE_NEW:
 165         return O_CREAT | O_EXCL;
 166         case FILE_MODE_CREATE:
 167         return O_CREAT | O_TRUNC;
 168         case FILE_MODE_OPEN:
 169                 return 0;
 170         case FILE_MODE_OPEN_OR_CREATE:
 171         return O_CREAT;
 172         case FILE_MODE_TRUNCATE:
 173         return O_TRUNC;
 174         case FILE_MODE_APPEND:
 175                 return O_APPEND;
 176         default:
 177                 g_error ("unknown FileMode %d", mode);
 178         }
 179 }
 180
 181 static int
 182 access_mode_to_unix (int access)
 183 {
 184         switch (access) {
 185         case MMAP_FILE_ACCESS_READ_WRITE:
 186         case MMAP_FILE_ACCESS_COPY_ON_WRITE:
 187         case MMAP_FILE_ACCESS_READ_WRITE_EXECUTE:
 188                 return O_RDWR;
 189         case MMAP_FILE_ACCESS_READ:
 190         case MMAP_FILE_ACCESS_READ_EXECUTE:
 191                 return O_RDONLY;
 192         case MMAP_FILE_ACCESS_WRITE:
 193                 return O_WRONLY;
 194         default:
 195                 g_error ("unknown MemoryMappedFileAccess %d", access);
 196         }
 197 }
 198
 199 static int
 200 acess_to_mmap_flags (int access)
 201 {
 202         switch (access) {
 203         case MMAP_FILE_ACCESS_READ_WRITE:
 204         return MONO_MMAP_WRITE | MONO_MMAP_READ | MONO_MMAP_SHARED;
 205
 206         case MMAP_FILE_ACCESS_WRITE:
 207         return MONO_MMAP_WRITE | MONO_MMAP_SHARED;
 208
 209         case MMAP_FILE_ACCESS_COPY_ON_WRITE:
 210         return MONO_MMAP_WRITE | MONO_MMAP_READ | MONO_MMAP_PRIVATE;
 211
 212         case MMAP_FILE_ACCESS_READ_EXECUTE:
 213         return MONO_MMAP_EXEC | MONO_MMAP_PRIVATE | MONO_MMAP_SHARED;
 214
 215         case MMAP_FILE_ACCESS_READ_WRITE_EXECUTE:
 216         return MONO_MMAP_WRITE | MONO_MMAP_READ | MONO_MMAP_EXEC | MONO_MMAP_SHARED;
 217
 218         case MMAP_FILE_ACCESS_READ:
 219         return MONO_MMAP_READ | MONO_MMAP_SHARED;
 220         default:
 221                 g_error ("unknown MemoryMappedFileAccess %d", access);
 222         }
 223 }
 224
 225 /*
 226 XXX implement options
 227 */
 228 static void*
 229 open_file_map (MonoString *path, int input_fd, int mode, gint64 *capacity, int access, int options, int *error)
 230 {
 231         struct stat buf;
 232         char *c_path = path ? mono_string_to_utf8 (path) : NULL;
 233         FileHandle *handle = NULL;
 234         int result, fd;
 235
 236         if (path)
 237                 result = stat (c_path, &buf);
 238         else
 239                 result = fstat (input_fd, &buf);
 240
 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;
 244                         goto done;
 245                 }
 246         }
 247
 248         if (mode == FILE_MODE_CREATE_NEW && result == 0) {
 249                 *error = FILE_ALREADY_EXISTS;
 250                 goto done;
 251         }
 252
 253         if (result == 0) {
 254                 if (*capacity == 0) {
 255                         /**
 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.
 258                          */
 259                         if (buf.st_size == 0 && (buf.st_mode & (S_IFCHR | S_IFBLK | S_IFIFO | S_IFSOCK)) == 0) {
 260                                 *error = CAPACITY_SMALLER_THAN_FILE_SIZE;
 261                                 goto done;
 262                         }
 263                         *capacity = buf.st_size;
 264                 } else if (*capacity < buf.st_size) {
 265                         *error = CAPACITY_SMALLER_THAN_FILE_SIZE;
 266                         goto done;
 267                 }
 268         } else {
 269                 if (mode == FILE_MODE_CREATE_NEW && *capacity == 0) {
 270                         *error = CAPACITY_SMALLER_THAN_FILE_SIZE;
 271                         goto done;
 272                 }
 273         }
 274
 275         if (path) //FIXME use io portability?
 276                 fd = open (c_path, file_mode_to_unix (mode) | access_mode_to_unix (access), DEFFILEMODE);
 277         else
 278                 fd = dup (input_fd);
 279
 280         if (fd == -1) { //XXX translate errno?
 281                 *error = COULD_NOT_OPEN;
 282                 goto done;
 283         }
 284
 285         *capacity = align_up_to_page_size ((size_t)*capacity);
 286
 287         if (*capacity > buf.st_size)
 288                 ftruncate (fd, (off_t)*capacity);
 289
 290         handle = g_new0 (FileHandle, 1);
 291         handle->handle.kind = MMAP_KIND_FILE;
 292         handle->handle.ref_count = 1;
 293         handle->handle.capacity = *capacity;
 294         handle->fd = fd;
 295
 296 done:
 297         g_free (c_path);
 298         return (void*)handle;
 299 }
 300
 301 static void*
 302 open_memory_map (MonoString *mapName, int mode, gint64 *capacity, int access, int options, int *error)
 303 {
 304         char *c_mapName;
 305         MemoryHandle *handle;
 306         if (*capacity <= 1) {
 307                 *error = CAPACITY_MUST_BE_POSITIVE;
 308                 return NULL;
 309         }
 310
 311         if (!(mode == FILE_MODE_CREATE_NEW || mode == FILE_MODE_OPEN_OR_CREATE || mode == FILE_MODE_OPEN)) {
 312                 *error = INVALID_FILE_MODE;
 313                 return NULL;
 314         }
 315
 316         c_mapName = mono_string_to_utf8 (mapName);
 317
 318         named_regions_lock ();
 319         handle = (MemoryHandle*)g_hash_table_lookup (named_regions, c_mapName);
 320         if (handle) {
 321                 if (mode == FILE_MODE_CREATE_NEW)
 322                         *error = FILE_ALREADY_EXISTS;
 323
 324                 handle->handle.ref_count++;
 325                 //XXX should we ftruncate if the file is smaller than capacity?
 326         } else {
 327                 if (mode == FILE_MODE_OPEN)
 328                         *error = FILE_NOT_FOUND;
 329
 330                 *capacity = align_up_to_page_size (*capacity);
 331
 332                 handle = g_new0 (MemoryHandle, 1);
 333                 handle->handle.kind = MMAP_KIND_MEMORY;
 334                 handle->handle.ref_count = 1;
 335                 handle->handle.capacity = *capacity;
 336                 handle->handle.name = g_strdup (c_mapName);
 337
 338                 //FIXME compute RWX from access
 339                 handle->address = mono_valloc (NULL, (size_t)*capacity, MONO_MMAP_READ | MONO_MMAP_WRITE | MONO_MMAP_PRIVATE | MONO_MMAP_ANON);
 340                 handle->length = (size_t)*capacity;
 341                 g_hash_table_insert (named_regions, handle->handle.name, handle);
 342         }
 343
 344         named_regions_unlock ();
 345
 346         g_free (c_mapName);
 347         return handle;
 348 }
 349
 350
 351 void *
 352 mono_mmap_open_file (MonoString *path, int mode, MonoString *mapName, gint64 *capacity, int access, int options, int *error)
 353 {
 354         g_assert (path || mapName);
 355
 356         if (!mapName)
 357                 return open_file_map (path, -1, mode, capacity, access, options, error);
 358
 359         if (path) {
 360                 FileHandle *file_handle;
 361                 char *c_mapName = mono_string_to_utf8 (mapName);
 362
 363                 named_regions_lock ();
 364                 file_handle = (FileHandle*)g_hash_table_lookup (named_regions, c_mapName);
 365                 if (file_handle) {
 366                         *error = FILE_ALREADY_EXISTS;
 367                         file_handle = NULL;
 368                 } else {
 369                         file_handle = open_file_map (path, -1, mode, capacity, access, options, error);
 370                         if (file_handle) {
 371                                 file_handle->handle.name = g_strdup (c_mapName);
 372                                 g_hash_table_insert (named_regions, file_handle->handle.name, file_handle);
 373                         }
 374                 }
 375                 named_regions_unlock ();
 376
 377                 g_free (c_mapName);
 378                 return file_handle;
 379         }
 380
 381         return open_memory_map (mapName, mode, capacity, access, options, error);
 382 }
 383
 384 void *
 385 mono_mmap_open_handle (void *handle, MonoString *mapName, gint64 *capacity, int access, int options, int *error)
 386 {
 387         FileHandle *file_handle;
 388         char *c_mapName = mono_string_to_utf8 (mapName);
 389
 390         named_regions_lock ();
 391         file_handle = (FileHandle*)g_hash_table_lookup (named_regions, c_mapName);
 392         if (file_handle) {
 393                 *error = FILE_ALREADY_EXISTS;
 394                 file_handle = NULL;
 395         } else {
 396                 //XXX we're exploiting wapi HANDLE == FD equivalence. THIS IS FRAGILE, create a _wapi_handle_to_fd call
 397                 file_handle = open_file_map (NULL, GPOINTER_TO_INT (handle), FILE_MODE_OPEN, capacity, access, options, error);
 398                 file_handle->handle.name = g_strdup (c_mapName);
 399                 g_hash_table_insert (named_regions, file_handle->handle.name, file_handle);
 400         }
 401         named_regions_unlock ();
 402
 403         g_free (c_mapName);
 404         return file_handle;
 405 }
 406
 407 void
 408 mono_mmap_close (void *mmap_handle)
 409 {
 410         Handle *handle = mmap_handle;
 411
 412         named_regions_lock ();
 413         --handle->ref_count;
 414         if (handle->ref_count == 0) {
 415                 if (handle->name)
 416                         g_hash_table_remove (named_regions, handle->name);
 417
 418                 g_free (handle->name);
 419                 if (handle->kind == MMAP_KIND_MEMORY)
 420                         mono_vfree (((MemoryHandle*)handle)->address, ((MemoryHandle*)handle)->length);
 421                 else
 422                         close (((FileHandle*)handle)->fd);
 423                 g_free (handle);
 424         }
 425         named_regions_unlock ();
 426 }
 427
 428 void
 429 mono_mmap_configure_inheritability (void *mmap_handle, gboolean inheritability)
 430 {
 431         FileHandle *h = mmap_handle;
 432         int fd, flags;
 433
 434         if (h->handle.kind != MMAP_KIND_FILE)
 435                 return;
 436
 437         fd = h->fd;
 438         flags = fcntl (fd, F_GETFD, 0);
 439         if (inheritability)
 440                 flags &= ~FD_CLOEXEC;
 441         else
 442                 flags |= FD_CLOEXEC;
 443         fcntl (fd, F_SETFD, flags);
 444 }
 445
 446 void
 447 mono_mmap_flush (void *mmap_handle)
 448 {
 449         MmapHandle *h = mmap_handle;
 450
 451         if (h)
 452                 msync (h->address, h->length, MS_SYNC);
 453 }
 454
 455 int
 456 mono_mmap_map (void *handle, gint64 offset, gint64 *size, int access, void **mmap_handle, void **base_address)
 457 {
 458         gint64 mmap_offset = 0;
 459         Handle *h = handle;
 460         MmapHandle res = { 0 };
 461         if (h->kind == MMAP_KIND_FILE) {
 462                 FileHandle *fh = (FileHandle*)h;
 463                 size_t eff_size = *size;
 464                 struct stat buf = { 0 };
 465                 fstat (fh->fd, &buf); //FIXME error handling
 466
 467                 if (eff_size == 0 || eff_size > buf.st_size)
 468                         eff_size = buf.st_size;
 469                 *size = eff_size;
 470
 471                 mmap_offset = align_down_to_page_size (offset);
 472                 eff_size += (offset - mmap_offset);
 473                 //FIXME translate some interesting errno values
 474                 res.address = mono_file_map ((size_t)eff_size, acess_to_mmap_flags (access), fh->fd, mmap_offset, &res.free_handle);
 475                 res.length = eff_size;
 476                 res.kind = MMAP_KIND_FILE;
 477
 478         } else {
 479                 MemoryHandle *mh = (MemoryHandle*)h;
 480                 size_t eff_size = *size;
 481
 482                 if (!eff_size)
 483                         eff_size = *size = mh->length;
 484                 mmap_offset = (size_t)mmap_offset;
 485                 res.address = (char*)mh->address + offset;
 486                 res.length = (size_t)size;
 487                 res.kind = MMAP_KIND_MEMORY;
 488         }
 489
 490         if (res.address) {
 491                 *mmap_handle = g_memdup (&res, sizeof (MmapHandle));
 492                 *base_address = (char*)res.address + (offset - mmap_offset);
 493                 return 0;
 494         }
 495
 496         *mmap_handle = NULL;
 497         *base_address = NULL;
 498         return COULD_NOT_MAP_MEMORY;
 499 }
 500
 501 gboolean
 502 mono_mmap_unmap (void *mmap_handle)
 503 {
 504         int res = 0;
 505         MmapHandle *h = mmap_handle;
 506
 507         if (h->kind == MMAP_KIND_FILE)
 508                 res = mono_file_unmap (h->address, h->free_handle);
 509
 510         g_free (h);
 511         return res == 0;
 512 }
 513
 514 #endif