lib/efi_loader/efi_file.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * EFI_FILE_PROTOCOL
   4  *
   5  * Copyright (c) 2017 Rob Clark
   6  */
   7
   8 #include <common.h>
   9 #include <charset.h>
  10 #include <efi_loader.h>
  11 #include <log.h>
  12 #include <malloc.h>
  13 #include <mapmem.h>
  14 #include <fs.h>
  15 #include <part.h>
  16
  17 /* GUID for file system information */
  18 const efi_guid_t efi_file_system_info_guid = EFI_FILE_SYSTEM_INFO_GUID;
  19
  20 /* GUID to obtain the volume label */
  21 const efi_guid_t efi_system_volume_label_id = EFI_FILE_SYSTEM_VOLUME_LABEL_ID;
  22
  23 struct file_system {
  24         struct efi_simple_file_system_protocol base;
  25         struct efi_device_path *dp;
  26         struct blk_desc *desc;
  27         int part;
  28 };
  29 #define to_fs(x) container_of(x, struct file_system, base)
  30
  31 struct file_handle {
  32         struct efi_file_handle base;
  33         struct file_system *fs;
  34         loff_t offset;       /* current file position/cursor */
  35         int isdir;
  36         u64 open_mode;
  37
  38         /* for reading a directory: */
  39         struct fs_dir_stream *dirs;
  40         struct fs_dirent *dent;
  41
  42         char path[0];
  43 };
  44 #define to_fh(x) container_of(x, struct file_handle, base)
  45
  46 static const struct efi_file_handle efi_file_handle_protocol;
  47
  48 static char *basename(struct file_handle *fh)
  49 {
  50         char *s = strrchr(fh->path, '/');
  51         if (s)
  52                 return s + 1;
  53         return fh->path;
  54 }
  55
  56 static int set_blk_dev(struct file_handle *fh)
  57 {
  58         return fs_set_blk_dev_with_part(fh->fs->desc, fh->fs->part);
  59 }
  60
  61 /**
  62  * is_dir() - check if file handle points to directory
  63  *
  64  * We assume that set_blk_dev(fh) has been called already.
  65  *
  66  * @fh:         file handle
  67  * Return:      true if file handle points to a directory
  68  */
  69 static int is_dir(struct file_handle *fh)
  70 {
  71         struct fs_dir_stream *dirs;
  72
  73         dirs = fs_opendir(fh->path);
  74         if (!dirs)
  75                 return 0;
  76
  77         fs_closedir(dirs);
  78
  79         return 1;
  80 }
  81
  82 /*
  83  * Normalize a path which may include either back or fwd slashes,
  84  * double slashes, . or .. entries in the path, etc.
  85  */
  86 static int sanitize_path(char *path)
  87 {
  88         char *p;
  89
  90         /* backslash to slash: */
  91         p = path;
  92         while ((p = strchr(p, '\\')))
  93                 *p++ = '/';
  94
  95         /* handle double-slashes: */
  96         p = path;
  97         while ((p = strstr(p, "//"))) {
  98                 char *src = p + 1;
  99                 memmove(p, src, strlen(src) + 1);
 100         }
 101
 102         /* handle extra /.'s */
 103         p = path;
 104         while ((p = strstr(p, "/."))) {
 105                 /*
 106                  * You'd be tempted to do this *after* handling ".."s
 107                  * below to avoid having to check if "/." is start of
 108                  * a "/..", but that won't have the correct results..
 109                  * for example, "/foo/./../bar" would get resolved to
 110                  * "/foo/bar" if you did these two passes in the other
 111                  * order
 112                  */
 113                 if (p[2] == '.') {
 114                         p += 2;
 115                         continue;
 116                 }
 117                 char *src = p + 2;
 118                 memmove(p, src, strlen(src) + 1);
 119         }
 120
 121         /* handle extra /..'s: */
 122         p = path;
 123         while ((p = strstr(p, "/.."))) {
 124                 char *src = p + 3;
 125
 126                 p--;
 127
 128                 /* find beginning of previous path entry: */
 129                 while (true) {
 130                         if (p < path)
 131                                 return -1;
 132                         if (*p == '/')
 133                                 break;
 134                         p--;
 135                 }
 136
 137                 memmove(p, src, strlen(src) + 1);
 138         }
 139
 140         return 0;
 141 }
 142
 143 /**
 144  * efi_create_file() - create file or directory
 145  *
 146  * @fh:                 file handle
 147  * @attributes:         attributes for newly created file
 148  * Returns:             0 for success
 149  */
 150 static int efi_create_file(struct file_handle *fh, u64 attributes)
 151 {
 152         loff_t actwrite;
 153         void *buffer = &actwrite;
 154
 155         if (attributes & EFI_FILE_DIRECTORY)
 156                 return fs_mkdir(fh->path);
 157         else
 158                 return fs_write(fh->path, map_to_sysmem(buffer), 0, 0,
 159                                 &actwrite);
 160 }
 161
 162 /**
 163  * file_open() - open a file handle
 164  *
 165  * @fs:                 file system
 166  * @parent:             directory relative to which the file is to be opened
 167  * @file_name:          path of the file to be opened. '\', '.', or '..' may
 168  *                      be used as modifiers. A leading backslash indicates an
 169  *                      absolute path.
 170  * @open_mode:          bit mask indicating the access mode (read, write,
 171  *                      create)
 172  * @attributes:         attributes for newly created file
 173  * Returns:             handle to the opened file or NULL
 174  */
 175 static struct efi_file_handle *file_open(struct file_system *fs,
 176                 struct file_handle *parent, u16 *file_name, u64 open_mode,
 177                 u64 attributes)
 178 {
 179         struct file_handle *fh;
 180         char f0[MAX_UTF8_PER_UTF16] = {0};
 181         int plen = 0;
 182         int flen = 0;
 183
 184         if (file_name) {
 185                 utf16_to_utf8((u8 *)f0, file_name, 1);
 186                 flen = u16_strlen(file_name);
 187         }
 188
 189         /* we could have a parent, but also an absolute path: */
 190         if (f0[0] == '\\') {
 191                 plen = 0;
 192         } else if (parent) {
 193                 plen = strlen(parent->path) + 1;
 194         }
 195
 196         /* +2 is for null and '/' */
 197         fh = calloc(1, sizeof(*fh) + plen + (flen * MAX_UTF8_PER_UTF16) + 2);
 198
 199         fh->open_mode = open_mode;
 200         fh->base = efi_file_handle_protocol;
 201         fh->fs = fs;
 202
 203         if (parent) {
 204                 char *p = fh->path;
 205                 int exists;
 206
 207                 if (plen > 0) {
 208                         strcpy(p, parent->path);
 209                         p += plen - 1;
 210                         *p++ = '/';
 211                 }
 212
 213                 utf16_to_utf8((u8 *)p, file_name, flen);
 214
 215                 if (sanitize_path(fh->path))
 216                         goto error;
 217
 218                 /* check if file exists: */
 219                 if (set_blk_dev(fh))
 220                         goto error;
 221
 222                 exists = fs_exists(fh->path);
 223                 /* fs_exists() calls fs_close(), so open file system again */
 224                 if (set_blk_dev(fh))
 225                         goto error;
 226
 227                 if (!exists) {
 228                         if (!(open_mode & EFI_FILE_MODE_CREATE) ||
 229                             efi_create_file(fh, attributes))
 230                                 goto error;
 231                         if (set_blk_dev(fh))
 232                                 goto error;
 233                 }
 234
 235                 /* figure out if file is a directory: */
 236                 fh->isdir = is_dir(fh);
 237         } else {
 238                 fh->isdir = 1;
 239                 strcpy(fh->path, "");
 240         }
 241
 242         return &fh->base;
 243
 244 error:
 245         free(fh);
 246         return NULL;
 247 }
 248
 249 static efi_status_t EFIAPI efi_file_open(struct efi_file_handle *file,
 250                 struct efi_file_handle **new_handle,
 251                 u16 *file_name, u64 open_mode, u64 attributes)
 252 {
 253         struct file_handle *fh = to_fh(file);
 254         efi_status_t ret;
 255
 256         EFI_ENTRY("%p, %p, \"%ls\", %llx, %llu", file, new_handle,
 257                   file_name, open_mode, attributes);
 258
 259         /* Check parameters */
 260         if (!file || !new_handle || !file_name) {
 261                 ret = EFI_INVALID_PARAMETER;
 262                 goto out;
 263         }
 264         if (open_mode != EFI_FILE_MODE_READ &&
 265             open_mode != (EFI_FILE_MODE_READ | EFI_FILE_MODE_WRITE) &&
 266             open_mode != (EFI_FILE_MODE_READ | EFI_FILE_MODE_WRITE |
 267                          EFI_FILE_MODE_CREATE)) {
 268                 ret = EFI_INVALID_PARAMETER;
 269                 goto out;
 270         }
 271         /*
 272          * The UEFI spec requires that attributes are only set in create mode.
 273          * The SCT does not care about this and sets EFI_FILE_DIRECTORY in
 274          * read mode. EDK2 does not check that attributes are zero if not in
 275          * create mode.
 276          *
 277          * So here we only check attributes in create mode and do not check
 278          * that they are zero otherwise.
 279          */
 280         if ((open_mode & EFI_FILE_MODE_CREATE) &&
 281             (attributes & (EFI_FILE_READ_ONLY | ~EFI_FILE_VALID_ATTR))) {
 282                 ret = EFI_INVALID_PARAMETER;
 283                 goto out;
 284         }
 285
 286         /* Open file */
 287         *new_handle = file_open(fh->fs, fh, file_name, open_mode, attributes);
 288         if (*new_handle) {
 289                 EFI_PRINT("file handle %p\n", *new_handle);
 290                 ret = EFI_SUCCESS;
 291         } else {
 292                 ret = EFI_NOT_FOUND;
 293         }
 294 out:
 295         return EFI_EXIT(ret);
 296 }
 297
 298 static efi_status_t file_close(struct file_handle *fh)
 299 {
 300         fs_closedir(fh->dirs);
 301         free(fh);
 302         return EFI_SUCCESS;
 303 }
 304
 305 static efi_status_t EFIAPI efi_file_close(struct efi_file_handle *file)
 306 {
 307         struct file_handle *fh = to_fh(file);
 308         EFI_ENTRY("%p", file);
 309         return EFI_EXIT(file_close(fh));
 310 }
 311
 312 static efi_status_t EFIAPI efi_file_delete(struct efi_file_handle *file)
 313 {
 314         struct file_handle *fh = to_fh(file);
 315         efi_status_t ret = EFI_SUCCESS;
 316
 317         EFI_ENTRY("%p", file);
 318
 319         if (set_blk_dev(fh) || fs_unlink(fh->path))
 320                 ret = EFI_WARN_DELETE_FAILURE;
 321
 322         file_close(fh);
 323         return EFI_EXIT(ret);
 324 }
 325
 326 /**
 327  * efi_get_file_size() - determine the size of a file
 328  *
 329  * @fh:         file handle
 330  * @file_size:  pointer to receive file size
 331  * Return:      status code
 332  */
 333 static efi_status_t efi_get_file_size(struct file_handle *fh,
 334                                       loff_t *file_size)
 335 {
 336         if (set_blk_dev(fh))
 337                 return EFI_DEVICE_ERROR;
 338
 339         if (fs_size(fh->path, file_size))
 340                 return EFI_DEVICE_ERROR;
 341
 342         return EFI_SUCCESS;
 343 }
 344
 345 static efi_status_t file_read(struct file_handle *fh, u64 *buffer_size,
 346                 void *buffer)
 347 {
 348         loff_t actread;
 349         efi_status_t ret;
 350         loff_t file_size;
 351
 352         ret = efi_get_file_size(fh, &file_size);
 353         if (ret != EFI_SUCCESS)
 354                 return ret;
 355         if (file_size < fh->offset) {
 356                 ret = EFI_DEVICE_ERROR;
 357                 return ret;
 358         }
 359
 360         if (set_blk_dev(fh))
 361                 return EFI_DEVICE_ERROR;
 362         if (fs_read(fh->path, map_to_sysmem(buffer), fh->offset,
 363                     *buffer_size, &actread))
 364                 return EFI_DEVICE_ERROR;
 365
 366         *buffer_size = actread;
 367         fh->offset += actread;
 368
 369         return EFI_SUCCESS;
 370 }
 371
 372 static efi_status_t dir_read(struct file_handle *fh, u64 *buffer_size,
 373                 void *buffer)
 374 {
 375         struct efi_file_info *info = buffer;
 376         struct fs_dirent *dent;
 377         u64 required_size;
 378         u16 *dst;
 379
 380         if (set_blk_dev(fh))
 381                 return EFI_DEVICE_ERROR;
 382
 383         if (!fh->dirs) {
 384                 assert(fh->offset == 0);
 385                 fh->dirs = fs_opendir(fh->path);
 386                 if (!fh->dirs)
 387                         return EFI_DEVICE_ERROR;
 388                 fh->dent = NULL;
 389         }
 390
 391         /*
 392          * So this is a bit awkward.  Since fs layer is stateful and we
 393          * can't rewind an entry, in the EFI_BUFFER_TOO_SMALL case below
 394          * we might have to return without consuming the dent.. so we
 395          * have to stash it for next call.
 396          */
 397         if (fh->dent) {
 398                 dent = fh->dent;
 399         } else {
 400                 dent = fs_readdir(fh->dirs);
 401         }
 402
 403         if (!dent) {
 404                 /* no more files in directory */
 405                 *buffer_size = 0;
 406                 return EFI_SUCCESS;
 407         }
 408
 409         /* check buffer size: */
 410         required_size = sizeof(*info) +
 411                         2 * (utf8_utf16_strlen(dent->name) + 1);
 412         if (*buffer_size < required_size) {
 413                 *buffer_size = required_size;
 414                 fh->dent = dent;
 415                 return EFI_BUFFER_TOO_SMALL;
 416         }
 417         fh->dent = NULL;
 418
 419         *buffer_size = required_size;
 420         memset(info, 0, required_size);
 421
 422         info->size = required_size;
 423         info->file_size = dent->size;
 424         info->physical_size = dent->size;
 425
 426         if (dent->type == FS_DT_DIR)
 427                 info->attribute |= EFI_FILE_DIRECTORY;
 428
 429         dst = info->file_name;
 430         utf8_utf16_strcpy(&dst, dent->name);
 431
 432         fh->offset++;
 433
 434         return EFI_SUCCESS;
 435 }
 436
 437 static efi_status_t EFIAPI efi_file_read(struct efi_file_handle *file,
 438                                          efi_uintn_t *buffer_size, void *buffer)
 439 {
 440         struct file_handle *fh = to_fh(file);
 441         efi_status_t ret = EFI_SUCCESS;
 442         u64 bs;
 443
 444         EFI_ENTRY("%p, %p, %p", file, buffer_size, buffer);
 445
 446         if (!buffer_size || !buffer) {
 447                 ret = EFI_INVALID_PARAMETER;
 448                 goto error;
 449         }
 450
 451         bs = *buffer_size;
 452         if (fh->isdir)
 453                 ret = dir_read(fh, &bs, buffer);
 454         else
 455                 ret = file_read(fh, &bs, buffer);
 456         if (bs <= SIZE_MAX)
 457                 *buffer_size = bs;
 458         else
 459                 *buffer_size = SIZE_MAX;
 460
 461 error:
 462         return EFI_EXIT(ret);
 463 }
 464
 465 /**
 466  * efi_file_write() - write to file
 467  *
 468  * This function implements the Write() service of the EFI_FILE_PROTOCOL.
 469  *
 470  * See the Unified Extensible Firmware Interface (UEFI) specification for
 471  * details.
 472  *
 473  * @file:               file handle
 474  * @buffer_size:        number of bytes to write
 475  * @buffer:             buffer with the bytes to write
 476  * Return:              status code
 477  */
 478 static efi_status_t EFIAPI efi_file_write(struct efi_file_handle *file,
 479                                           efi_uintn_t *buffer_size,
 480                                           void *buffer)
 481 {
 482         struct file_handle *fh = to_fh(file);
 483         efi_status_t ret = EFI_SUCCESS;
 484         loff_t actwrite;
 485
 486         EFI_ENTRY("%p, %p, %p", file, buffer_size, buffer);
 487
 488         if (!file || !buffer_size || !buffer) {
 489                 ret = EFI_INVALID_PARAMETER;
 490                 goto out;
 491         }
 492         if (fh->isdir) {
 493                 ret = EFI_UNSUPPORTED;
 494                 goto out;
 495         }
 496         if (!(fh->open_mode & EFI_FILE_MODE_WRITE)) {
 497                 ret = EFI_ACCESS_DENIED;
 498                 goto out;
 499         }
 500
 501         if (!*buffer_size)
 502                 goto out;
 503
 504         if (set_blk_dev(fh)) {
 505                 ret = EFI_DEVICE_ERROR;
 506                 goto out;
 507         }
 508         if (fs_write(fh->path, map_to_sysmem(buffer), fh->offset, *buffer_size,
 509                      &actwrite)) {
 510                 ret = EFI_DEVICE_ERROR;
 511                 goto out;
 512         }
 513         *buffer_size = actwrite;
 514         fh->offset += actwrite;
 515
 516 out:
 517         return EFI_EXIT(ret);
 518 }
 519
 520 /**
 521  * efi_file_getpos() - get current position in file
 522  *
 523  * This function implements the GetPosition service of the EFI file protocol.
 524  * See the UEFI spec for details.
 525  *
 526  * @file:       file handle
 527  * @pos:        pointer to file position
 528  * Return:      status code
 529  */
 530 static efi_status_t EFIAPI efi_file_getpos(struct efi_file_handle *file,
 531                                            u64 *pos)
 532 {
 533         efi_status_t ret = EFI_SUCCESS;
 534         struct file_handle *fh = to_fh(file);
 535
 536         EFI_ENTRY("%p, %p", file, pos);
 537
 538         if (fh->isdir) {
 539                 ret = EFI_UNSUPPORTED;
 540                 goto out;
 541         }
 542
 543         *pos = fh->offset;
 544 out:
 545         return EFI_EXIT(ret);
 546 }
 547
 548 /**
 549  * efi_file_setpos() - set current position in file
 550  *
 551  * This function implements the SetPosition service of the EFI file protocol.
 552  * See the UEFI spec for details.
 553  *
 554  * @file:       file handle
 555  * @pos:        new file position
 556  * Return:      status code
 557  */
 558 static efi_status_t EFIAPI efi_file_setpos(struct efi_file_handle *file,
 559                                            u64 pos)
 560 {
 561         struct file_handle *fh = to_fh(file);
 562         efi_status_t ret = EFI_SUCCESS;
 563
 564         EFI_ENTRY("%p, %llu", file, pos);
 565
 566         if (fh->isdir) {
 567                 if (pos != 0) {
 568                         ret = EFI_UNSUPPORTED;
 569                         goto error;
 570                 }
 571                 fs_closedir(fh->dirs);
 572                 fh->dirs = NULL;
 573         }
 574
 575         if (pos == ~0ULL) {
 576                 loff_t file_size;
 577
 578                 ret = efi_get_file_size(fh, &file_size);
 579                 if (ret != EFI_SUCCESS)
 580                         goto error;
 581                 pos = file_size;
 582         }
 583
 584         fh->offset = pos;
 585
 586 error:
 587         return EFI_EXIT(ret);
 588 }
 589
 590 static efi_status_t EFIAPI efi_file_getinfo(struct efi_file_handle *file,
 591                                             const efi_guid_t *info_type,
 592                                             efi_uintn_t *buffer_size,
 593                                             void *buffer)
 594 {
 595         struct file_handle *fh = to_fh(file);
 596         efi_status_t ret = EFI_SUCCESS;
 597         u16 *dst;
 598
 599         EFI_ENTRY("%p, %pUl, %p, %p", file, info_type, buffer_size, buffer);
 600
 601         if (!file || !info_type || !buffer_size ||
 602             (*buffer_size && !buffer)) {
 603                 ret = EFI_INVALID_PARAMETER;
 604                 goto error;
 605         }
 606
 607         if (!guidcmp(info_type, &efi_file_info_guid)) {
 608                 struct efi_file_info *info = buffer;
 609                 char *filename = basename(fh);
 610                 unsigned int required_size;
 611                 loff_t file_size;
 612
 613                 /* check buffer size: */
 614                 required_size = sizeof(*info) +
 615                                 2 * (utf8_utf16_strlen(filename) + 1);
 616                 if (*buffer_size < required_size) {
 617                         *buffer_size = required_size;
 618                         ret = EFI_BUFFER_TOO_SMALL;
 619                         goto error;
 620                 }
 621
 622                 ret = efi_get_file_size(fh, &file_size);
 623                 if (ret != EFI_SUCCESS)
 624                         goto error;
 625
 626                 memset(info, 0, required_size);
 627
 628                 info->size = required_size;
 629                 info->file_size = file_size;
 630                 info->physical_size = file_size;
 631
 632                 if (fh->isdir)
 633                         info->attribute |= EFI_FILE_DIRECTORY;
 634
 635                 dst = info->file_name;
 636                 utf8_utf16_strcpy(&dst, filename);
 637         } else if (!guidcmp(info_type, &efi_file_system_info_guid)) {
 638                 struct efi_file_system_info *info = buffer;
 639                 struct disk_partition part;
 640                 efi_uintn_t required_size;
 641                 int r;
 642
 643                 if (fh->fs->part >= 1)
 644                         r = part_get_info(fh->fs->desc, fh->fs->part, &part);
 645                 else
 646                         r = part_get_info_whole_disk(fh->fs->desc, &part);
 647                 if (r < 0) {
 648                         ret = EFI_DEVICE_ERROR;
 649                         goto error;
 650                 }
 651                 required_size = sizeof(*info) + 2;
 652                 if (*buffer_size < required_size) {
 653                         *buffer_size = required_size;
 654                         ret = EFI_BUFFER_TOO_SMALL;
 655                         goto error;
 656                 }
 657
 658                 memset(info, 0, required_size);
 659
 660                 info->size = required_size;
 661                 /*
 662                  * TODO: We cannot determine if the volume can be written to.
 663                  */
 664                 info->read_only = false;
 665                 info->volume_size = part.size * part.blksz;
 666                 /*
 667                  * TODO: We currently have no function to determine the free
 668                  * space. The volume size is the best upper bound we have.
 669                  */
 670                 info->free_space = info->volume_size;
 671                 info->block_size = part.blksz;
 672                 /*
 673                  * TODO: The volume label is not available in U-Boot.
 674                  */
 675                 info->volume_label[0] = 0;
 676         } else if (!guidcmp(info_type, &efi_system_volume_label_id)) {
 677                 if (*buffer_size < 2) {
 678                         *buffer_size = 2;
 679                         ret = EFI_BUFFER_TOO_SMALL;
 680                         goto error;
 681                 }
 682                 *(u16 *)buffer = 0;
 683         } else {
 684                 ret = EFI_UNSUPPORTED;
 685         }
 686
 687 error:
 688         return EFI_EXIT(ret);
 689 }
 690
 691 static efi_status_t EFIAPI efi_file_setinfo(struct efi_file_handle *file,
 692                                             const efi_guid_t *info_type,
 693                                             efi_uintn_t buffer_size,
 694                                             void *buffer)
 695 {
 696         struct file_handle *fh = to_fh(file);
 697         efi_status_t ret = EFI_UNSUPPORTED;
 698
 699         EFI_ENTRY("%p, %pUl, %zu, %p", file, info_type, buffer_size, buffer);
 700
 701         if (!guidcmp(info_type, &efi_file_info_guid)) {
 702                 struct efi_file_info *info = (struct efi_file_info *)buffer;
 703                 char *filename = basename(fh);
 704                 char *new_file_name, *pos;
 705                 loff_t file_size;
 706
 707                 /* The buffer will always contain a file name. */
 708                 if (buffer_size < sizeof(struct efi_file_info) + 2 ||
 709                     buffer_size < info->size) {
 710                         ret = EFI_BAD_BUFFER_SIZE;
 711                         goto out;
 712                 }
 713                 /* We cannot change the directory attribute */
 714                 if (!fh->isdir != !(info->attribute & EFI_FILE_DIRECTORY)) {
 715                         ret = EFI_ACCESS_DENIED;
 716                         goto out;
 717                 }
 718                 /* Check for renaming */
 719                 new_file_name = malloc(utf16_utf8_strlen(info->file_name));
 720                 if (!new_file_name) {
 721                         ret = EFI_OUT_OF_RESOURCES;
 722                         goto out;
 723                 }
 724                 pos = new_file_name;
 725                 utf16_utf8_strcpy(&pos, info->file_name);
 726                 if (strcmp(new_file_name, filename)) {
 727                         /* TODO: we do not support renaming */
 728                         EFI_PRINT("Renaming not supported\n");
 729                         free(new_file_name);
 730                         ret = EFI_ACCESS_DENIED;
 731                         goto out;
 732                 }
 733                 free(new_file_name);
 734                 /* Check for truncation */
 735                 ret = efi_get_file_size(fh, &file_size);
 736                 if (ret != EFI_SUCCESS)
 737                         goto out;
 738                 if (file_size != info->file_size) {
 739                         /* TODO: we do not support truncation */
 740                         EFI_PRINT("Truncation not supported\n");
 741                         ret = EFI_ACCESS_DENIED;
 742                         goto out;
 743                 }
 744                 /*
 745                  * We do not care for the other attributes
 746                  * TODO: Support read only
 747                  */
 748                 ret = EFI_SUCCESS;
 749         } else {
 750                 /* TODO: We do not support changing the volume label */
 751                 ret = EFI_UNSUPPORTED;
 752         }
 753 out:
 754         return EFI_EXIT(ret);
 755 }
 756
 757 static efi_status_t EFIAPI efi_file_flush(struct efi_file_handle *file)
 758 {
 759         EFI_ENTRY("%p", file);
 760         return EFI_EXIT(EFI_SUCCESS);
 761 }
 762
 763 static efi_status_t EFIAPI efi_file_open_ex(struct efi_file_handle *file,
 764                         struct efi_file_handle **new_handle,
 765                         u16 *file_name, u64 open_mode, u64 attributes,
 766                         struct efi_file_io_token *token)
 767 {
 768         return EFI_UNSUPPORTED;
 769 }
 770
 771 static efi_status_t EFIAPI efi_file_read_ex(struct efi_file_handle *file,
 772                         struct efi_file_io_token *token)
 773 {
 774         return EFI_UNSUPPORTED;
 775 }
 776
 777 static efi_status_t EFIAPI efi_file_write_ex(struct efi_file_handle *file,
 778                         struct efi_file_io_token *token)
 779 {
 780         return EFI_UNSUPPORTED;
 781 }
 782
 783 static efi_status_t EFIAPI efi_file_flush_ex(struct efi_file_handle *file,
 784                         struct efi_file_io_token *token)
 785 {
 786         return EFI_UNSUPPORTED;
 787 }
 788
 789 static const struct efi_file_handle efi_file_handle_protocol = {
 790         .rev = EFI_FILE_PROTOCOL_REVISION2,
 791         .open = efi_file_open,
 792         .close = efi_file_close,
 793         .delete = efi_file_delete,
 794         .read = efi_file_read,
 795         .write = efi_file_write,
 796         .getpos = efi_file_getpos,
 797         .setpos = efi_file_setpos,
 798         .getinfo = efi_file_getinfo,
 799         .setinfo = efi_file_setinfo,
 800         .flush = efi_file_flush,
 801         .open_ex = efi_file_open_ex,
 802         .read_ex = efi_file_read_ex,
 803         .write_ex = efi_file_write_ex,
 804         .flush_ex = efi_file_flush_ex,
 805 };
 806
 807 /**
 808  * efi_file_from_path() - open file via device path
 809  *
 810  * @fp:         device path
 811  * @return:     EFI_FILE_PROTOCOL for the file or NULL
 812  */
 813 struct efi_file_handle *efi_file_from_path(struct efi_device_path *fp)
 814 {
 815         struct efi_simple_file_system_protocol *v;
 816         struct efi_file_handle *f;
 817         efi_status_t ret;
 818
 819         v = efi_fs_from_path(fp);
 820         if (!v)
 821                 return NULL;
 822
 823         EFI_CALL(ret = v->open_volume(v, &f));
 824         if (ret != EFI_SUCCESS)
 825                 return NULL;
 826
 827         /* Skip over device-path nodes before the file path. */
 828         while (fp && !EFI_DP_TYPE(fp, MEDIA_DEVICE, FILE_PATH))
 829                 fp = efi_dp_next(fp);
 830
 831         /*
 832          * Step through the nodes of the directory path until the actual file
 833          * node is reached which is the final node in the device path.
 834          */
 835         while (fp) {
 836                 struct efi_device_path_file_path *fdp =
 837                         container_of(fp, struct efi_device_path_file_path, dp);
 838                 struct efi_file_handle *f2;
 839                 u16 *filename;
 840
 841                 if (!EFI_DP_TYPE(fp, MEDIA_DEVICE, FILE_PATH)) {
 842                         printf("bad file path!\n");
 843                         f->close(f);
 844                         return NULL;
 845                 }
 846
 847                 filename = u16_strdup(fdp->str);
 848                 if (!filename)
 849                         return NULL;
 850                 EFI_CALL(ret = f->open(f, &f2, filename,
 851                                        EFI_FILE_MODE_READ, 0));
 852                 free(filename);
 853                 if (ret != EFI_SUCCESS)
 854                         return NULL;
 855
 856                 fp = efi_dp_next(fp);
 857
 858                 EFI_CALL(f->close(f));
 859                 f = f2;
 860         }
 861
 862         return f;
 863 }
 864
 865 static efi_status_t EFIAPI
 866 efi_open_volume(struct efi_simple_file_system_protocol *this,
 867                 struct efi_file_handle **root)
 868 {
 869         struct file_system *fs = to_fs(this);
 870
 871         EFI_ENTRY("%p, %p", this, root);
 872
 873         *root = file_open(fs, NULL, NULL, 0, 0);
 874
 875         return EFI_EXIT(EFI_SUCCESS);
 876 }
 877
 878 struct efi_simple_file_system_protocol *
 879 efi_simple_file_system(struct blk_desc *desc, int part,
 880                        struct efi_device_path *dp)
 881 {
 882         struct file_system *fs;
 883
 884         fs = calloc(1, sizeof(*fs));
 885         fs->base.rev = EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_REVISION;
 886         fs->base.open_volume = efi_open_volume;
 887         fs->desc = desc;
 888         fs->part = part;
 889         fs->dp = dp;
 890
 891         return &fs->base;
 892 }