xref: /openbmc/u-boot/fs/fat/fat.c (revision e712e545)
1 /*
2  * fat.c
3  *
4  * R/O (V)FAT 12/16/32 filesystem implementation by Marcus Sundberg
5  *
6  * 2002-07-28 - rjones@nexus-tech.net - ported to ppcboot v1.1.6
7  * 2003-03-10 - kharris@nexus-tech.net - ported to uboot
8  *
9  * See file CREDITS for list of people who contributed to this
10  * project.
11  *
12  * This program is free software; you can redistribute it and/or
13  * modify it under the terms of the GNU General Public License as
14  * published by the Free Software Foundation; either version 2 of
15  * the License, or (at your option) any later version.
16  *
17  * This program is distributed in the hope that it will be useful,
18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
20  * GNU General Public License for more details.
21  *
22  * You should have received a copy of the GNU General Public License
23  * along with this program; if not, write to the Free Software
24  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
25  * MA 02111-1307 USA
26  */
27 
28 #include <common.h>
29 #include <config.h>
30 #include <exports.h>
31 #include <fat.h>
32 #include <asm/byteorder.h>
33 #include <part.h>
34 
35 /*
36  * Convert a string to lowercase.
37  */
38 static void downcase (char *str)
39 {
40 	while (*str != '\0') {
41 		TOLOWER(*str);
42 		str++;
43 	}
44 }
45 
46 static block_dev_desc_t *cur_dev;
47 static unsigned int cur_part_nr;
48 static disk_partition_t cur_part_info;
49 
50 #define DOS_BOOT_MAGIC_OFFSET	0x1fe
51 #define DOS_FS_TYPE_OFFSET	0x36
52 #define DOS_FS32_TYPE_OFFSET	0x52
53 
54 static int disk_read(__u32 block, __u32 nr_blocks, void *buf)
55 {
56 	if (!cur_dev || !cur_dev->block_read)
57 		return -1;
58 
59 	return cur_dev->block_read(cur_dev->dev,
60 			cur_part_info.start + block, nr_blocks, buf);
61 }
62 
63 int fat_register_device (block_dev_desc_t * dev_desc, int part_no)
64 {
65 	unsigned char buffer[dev_desc->blksz];
66 
67 	/* First close any currently found FAT filesystem */
68 	cur_dev = NULL;
69 
70 #if (defined(CONFIG_CMD_IDE) || \
71      defined(CONFIG_CMD_MG_DISK) || \
72      defined(CONFIG_CMD_SATA) || \
73      defined(CONFIG_CMD_SCSI) || \
74      defined(CONFIG_CMD_USB) || \
75      defined(CONFIG_MMC) || \
76      defined(CONFIG_SYSTEMACE) )
77 
78 	/* Read the partition table, if present */
79 	if (!get_partition_info(dev_desc, part_no, &cur_part_info)) {
80 		cur_dev = dev_desc;
81 		cur_part_nr = part_no;
82 	}
83 #endif
84 
85 	/* Otherwise it might be a superfloppy (whole-disk FAT filesystem) */
86 	if (!cur_dev) {
87 		if (part_no != 1) {
88 			printf("** Partition %d not valid on device %d **\n",
89 					part_no, dev_desc->dev);
90 			return -1;
91 		}
92 
93 		cur_dev = dev_desc;
94 		cur_part_nr = 1;
95 		cur_part_info.start = 0;
96 		cur_part_info.size = dev_desc->lba;
97 		cur_part_info.blksz = dev_desc->blksz;
98 		memset(cur_part_info.name, 0, sizeof(cur_part_info.name));
99 		memset(cur_part_info.type, 0, sizeof(cur_part_info.type));
100 	}
101 
102 	/* Make sure it has a valid FAT header */
103 	if (disk_read(0, 1, buffer) != 1) {
104 		cur_dev = NULL;
105 		return -1;
106 	}
107 
108 	/* Check if it's actually a DOS volume */
109 	if (memcmp(buffer + DOS_BOOT_MAGIC_OFFSET, "\x55\xAA", 2)) {
110 		cur_dev = NULL;
111 		return -1;
112 	}
113 
114 	/* Check for FAT12/FAT16/FAT32 filesystem */
115 	if (!memcmp(buffer + DOS_FS_TYPE_OFFSET, "FAT", 3))
116 		return 0;
117 	if (!memcmp(buffer + DOS_FS32_TYPE_OFFSET, "FAT32", 5))
118 		return 0;
119 
120 	cur_dev = NULL;
121 	return -1;
122 }
123 
124 
125 /*
126  * Get the first occurence of a directory delimiter ('/' or '\') in a string.
127  * Return index into string if found, -1 otherwise.
128  */
129 static int dirdelim (char *str)
130 {
131 	char *start = str;
132 
133 	while (*str != '\0') {
134 		if (ISDIRDELIM(*str))
135 			return str - start;
136 		str++;
137 	}
138 	return -1;
139 }
140 
141 /*
142  * Extract zero terminated short name from a directory entry.
143  */
144 static void get_name (dir_entry *dirent, char *s_name)
145 {
146 	char *ptr;
147 
148 	memcpy(s_name, dirent->name, 8);
149 	s_name[8] = '\0';
150 	ptr = s_name;
151 	while (*ptr && *ptr != ' ')
152 		ptr++;
153 	if (dirent->ext[0] && dirent->ext[0] != ' ') {
154 		*ptr = '.';
155 		ptr++;
156 		memcpy(ptr, dirent->ext, 3);
157 		ptr[3] = '\0';
158 		while (*ptr && *ptr != ' ')
159 			ptr++;
160 	}
161 	*ptr = '\0';
162 	if (*s_name == DELETED_FLAG)
163 		*s_name = '\0';
164 	else if (*s_name == aRING)
165 		*s_name = DELETED_FLAG;
166 	downcase(s_name);
167 }
168 
169 /*
170  * Get the entry at index 'entry' in a FAT (12/16/32) table.
171  * On failure 0x00 is returned.
172  */
173 static __u32 get_fatent (fsdata *mydata, __u32 entry)
174 {
175 	__u32 bufnum;
176 	__u32 off16, offset;
177 	__u32 ret = 0x00;
178 	__u16 val1, val2;
179 
180 	switch (mydata->fatsize) {
181 	case 32:
182 		bufnum = entry / FAT32BUFSIZE;
183 		offset = entry - bufnum * FAT32BUFSIZE;
184 		break;
185 	case 16:
186 		bufnum = entry / FAT16BUFSIZE;
187 		offset = entry - bufnum * FAT16BUFSIZE;
188 		break;
189 	case 12:
190 		bufnum = entry / FAT12BUFSIZE;
191 		offset = entry - bufnum * FAT12BUFSIZE;
192 		break;
193 
194 	default:
195 		/* Unsupported FAT size */
196 		return ret;
197 	}
198 
199 	debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
200 	       mydata->fatsize, entry, entry, offset, offset);
201 
202 	/* Read a new block of FAT entries into the cache. */
203 	if (bufnum != mydata->fatbufnum) {
204 		__u32 getsize = FATBUFBLOCKS;
205 		__u8 *bufptr = mydata->fatbuf;
206 		__u32 fatlength = mydata->fatlength;
207 		__u32 startblock = bufnum * FATBUFBLOCKS;
208 
209 		if (getsize > fatlength)
210 			getsize = fatlength;
211 
212 		fatlength *= mydata->sect_size;	/* We want it in bytes now */
213 		startblock += mydata->fat_sect;	/* Offset from start of disk */
214 
215 		if (disk_read(startblock, getsize, bufptr) < 0) {
216 			debug("Error reading FAT blocks\n");
217 			return ret;
218 		}
219 		mydata->fatbufnum = bufnum;
220 	}
221 
222 	/* Get the actual entry from the table */
223 	switch (mydata->fatsize) {
224 	case 32:
225 		ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
226 		break;
227 	case 16:
228 		ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
229 		break;
230 	case 12:
231 		off16 = (offset * 3) / 4;
232 
233 		switch (offset & 0x3) {
234 		case 0:
235 			ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[off16]);
236 			ret &= 0xfff;
237 			break;
238 		case 1:
239 			val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
240 			val1 &= 0xf000;
241 			val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
242 			val2 &= 0x00ff;
243 			ret = (val2 << 4) | (val1 >> 12);
244 			break;
245 		case 2:
246 			val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
247 			val1 &= 0xff00;
248 			val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
249 			val2 &= 0x000f;
250 			ret = (val2 << 8) | (val1 >> 8);
251 			break;
252 		case 3:
253 			ret = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
254 			ret = (ret & 0xfff0) >> 4;
255 			break;
256 		default:
257 			break;
258 		}
259 		break;
260 	}
261 	debug("FAT%d: ret: %08x, offset: %04x\n",
262 	       mydata->fatsize, ret, offset);
263 
264 	return ret;
265 }
266 
267 /*
268  * Read at most 'size' bytes from the specified cluster into 'buffer'.
269  * Return 0 on success, -1 otherwise.
270  */
271 static int
272 get_cluster (fsdata *mydata, __u32 clustnum, __u8 *buffer,
273 	     unsigned long size)
274 {
275 	__u32 idx = 0;
276 	__u32 startsect;
277 	__u32 nr_sect;
278 	int ret;
279 
280 	if (clustnum > 0) {
281 		startsect = mydata->data_begin +
282 				clustnum * mydata->clust_size;
283 	} else {
284 		startsect = mydata->rootdir_sect;
285 	}
286 
287 	debug("gc - clustnum: %d, startsect: %d\n", clustnum, startsect);
288 
289 	nr_sect = size / mydata->sect_size;
290 	ret = disk_read(startsect, nr_sect, buffer);
291 	if (ret != nr_sect) {
292 		debug("Error reading data (got %d)\n", ret);
293 		return -1;
294 	}
295 	if (size % mydata->sect_size) {
296 		__u8 tmpbuf[mydata->sect_size];
297 
298 		idx = size / mydata->sect_size;
299 		ret = disk_read(startsect + idx, 1, tmpbuf);
300 		if (ret != 1) {
301 			debug("Error reading data (got %d)\n", ret);
302 			return -1;
303 		}
304 		buffer += idx * mydata->sect_size;
305 
306 		memcpy(buffer, tmpbuf, size % mydata->sect_size);
307 		return 0;
308 	}
309 
310 	return 0;
311 }
312 
313 /*
314  * Read at most 'maxsize' bytes from the file associated with 'dentptr'
315  * into 'buffer'.
316  * Return the number of bytes read or -1 on fatal errors.
317  */
318 static long
319 get_contents (fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
320 	      unsigned long maxsize)
321 {
322 	unsigned long filesize = FAT2CPU32(dentptr->size), gotsize = 0;
323 	unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
324 	__u32 curclust = START(dentptr);
325 	__u32 endclust, newclust;
326 	unsigned long actsize;
327 
328 	debug("Filesize: %ld bytes\n", filesize);
329 
330 	if (maxsize > 0 && filesize > maxsize)
331 		filesize = maxsize;
332 
333 	debug("%ld bytes\n", filesize);
334 
335 	actsize = bytesperclust;
336 	endclust = curclust;
337 
338 	do {
339 		/* search for consecutive clusters */
340 		while (actsize < filesize) {
341 			newclust = get_fatent(mydata, endclust);
342 			if ((newclust - 1) != endclust)
343 				goto getit;
344 			if (CHECK_CLUST(newclust, mydata->fatsize)) {
345 				debug("curclust: 0x%x\n", newclust);
346 				debug("Invalid FAT entry\n");
347 				return gotsize;
348 			}
349 			endclust = newclust;
350 			actsize += bytesperclust;
351 		}
352 
353 		/* actsize >= file size */
354 		actsize -= bytesperclust;
355 
356 		/* get remaining clusters */
357 		if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
358 			printf("Error reading cluster\n");
359 			return -1;
360 		}
361 
362 		/* get remaining bytes */
363 		gotsize += (int)actsize;
364 		filesize -= actsize;
365 		buffer += actsize;
366 		actsize = filesize;
367 		if (get_cluster(mydata, endclust, buffer, (int)actsize) != 0) {
368 			printf("Error reading cluster\n");
369 			return -1;
370 		}
371 		gotsize += actsize;
372 		return gotsize;
373 getit:
374 		if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
375 			printf("Error reading cluster\n");
376 			return -1;
377 		}
378 		gotsize += (int)actsize;
379 		filesize -= actsize;
380 		buffer += actsize;
381 
382 		curclust = get_fatent(mydata, endclust);
383 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
384 			debug("curclust: 0x%x\n", curclust);
385 			printf("Invalid FAT entry\n");
386 			return gotsize;
387 		}
388 		actsize = bytesperclust;
389 		endclust = curclust;
390 	} while (1);
391 }
392 
393 #ifdef CONFIG_SUPPORT_VFAT
394 /*
395  * Extract the file name information from 'slotptr' into 'l_name',
396  * starting at l_name[*idx].
397  * Return 1 if terminator (zero byte) is found, 0 otherwise.
398  */
399 static int slot2str (dir_slot *slotptr, char *l_name, int *idx)
400 {
401 	int j;
402 
403 	for (j = 0; j <= 8; j += 2) {
404 		l_name[*idx] = slotptr->name0_4[j];
405 		if (l_name[*idx] == 0x00)
406 			return 1;
407 		(*idx)++;
408 	}
409 	for (j = 0; j <= 10; j += 2) {
410 		l_name[*idx] = slotptr->name5_10[j];
411 		if (l_name[*idx] == 0x00)
412 			return 1;
413 		(*idx)++;
414 	}
415 	for (j = 0; j <= 2; j += 2) {
416 		l_name[*idx] = slotptr->name11_12[j];
417 		if (l_name[*idx] == 0x00)
418 			return 1;
419 		(*idx)++;
420 	}
421 
422 	return 0;
423 }
424 
425 /*
426  * Extract the full long filename starting at 'retdent' (which is really
427  * a slot) into 'l_name'. If successful also copy the real directory entry
428  * into 'retdent'
429  * Return 0 on success, -1 otherwise.
430  */
431 __attribute__ ((__aligned__ (__alignof__ (dir_entry))))
432 __u8 get_vfatname_block[MAX_CLUSTSIZE];
433 
434 static int
435 get_vfatname (fsdata *mydata, int curclust, __u8 *cluster,
436 	      dir_entry *retdent, char *l_name)
437 {
438 	dir_entry *realdent;
439 	dir_slot *slotptr = (dir_slot *)retdent;
440 	__u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
441 							PREFETCH_BLOCKS :
442 							mydata->clust_size);
443 	__u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
444 	int idx = 0;
445 
446 	if (counter > VFAT_MAXSEQ) {
447 		debug("Error: VFAT name is too long\n");
448 		return -1;
449 	}
450 
451 	while ((__u8 *)slotptr < buflimit) {
452 		if (counter == 0)
453 			break;
454 		if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
455 			return -1;
456 		slotptr++;
457 		counter--;
458 	}
459 
460 	if ((__u8 *)slotptr >= buflimit) {
461 		dir_slot *slotptr2;
462 
463 		if (curclust == 0)
464 			return -1;
465 		curclust = get_fatent(mydata, curclust);
466 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
467 			debug("curclust: 0x%x\n", curclust);
468 			printf("Invalid FAT entry\n");
469 			return -1;
470 		}
471 
472 		if (get_cluster(mydata, curclust, get_vfatname_block,
473 				mydata->clust_size * mydata->sect_size) != 0) {
474 			debug("Error: reading directory block\n");
475 			return -1;
476 		}
477 
478 		slotptr2 = (dir_slot *)get_vfatname_block;
479 		while (counter > 0) {
480 			if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
481 			    & 0xff) != counter)
482 				return -1;
483 			slotptr2++;
484 			counter--;
485 		}
486 
487 		/* Save the real directory entry */
488 		realdent = (dir_entry *)slotptr2;
489 		while ((__u8 *)slotptr2 > get_vfatname_block) {
490 			slotptr2--;
491 			slot2str(slotptr2, l_name, &idx);
492 		}
493 	} else {
494 		/* Save the real directory entry */
495 		realdent = (dir_entry *)slotptr;
496 	}
497 
498 	do {
499 		slotptr--;
500 		if (slot2str(slotptr, l_name, &idx))
501 			break;
502 	} while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
503 
504 	l_name[idx] = '\0';
505 	if (*l_name == DELETED_FLAG)
506 		*l_name = '\0';
507 	else if (*l_name == aRING)
508 		*l_name = DELETED_FLAG;
509 	downcase(l_name);
510 
511 	/* Return the real directory entry */
512 	memcpy(retdent, realdent, sizeof(dir_entry));
513 
514 	return 0;
515 }
516 
517 /* Calculate short name checksum */
518 static __u8 mkcksum (const char *str)
519 {
520 	int i;
521 
522 	__u8 ret = 0;
523 
524 	for (i = 0; i < 11; i++) {
525 		ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + str[i];
526 	}
527 
528 	return ret;
529 }
530 #endif	/* CONFIG_SUPPORT_VFAT */
531 
532 /*
533  * Get the directory entry associated with 'filename' from the directory
534  * starting at 'startsect'
535  */
536 __attribute__ ((__aligned__ (__alignof__ (dir_entry))))
537 __u8 get_dentfromdir_block[MAX_CLUSTSIZE];
538 
539 static dir_entry *get_dentfromdir (fsdata *mydata, int startsect,
540 				   char *filename, dir_entry *retdent,
541 				   int dols)
542 {
543 	__u16 prevcksum = 0xffff;
544 	__u32 curclust = START(retdent);
545 	int files = 0, dirs = 0;
546 
547 	debug("get_dentfromdir: %s\n", filename);
548 
549 	while (1) {
550 		dir_entry *dentptr;
551 
552 		int i;
553 
554 		if (get_cluster(mydata, curclust, get_dentfromdir_block,
555 				mydata->clust_size * mydata->sect_size) != 0) {
556 			debug("Error: reading directory block\n");
557 			return NULL;
558 		}
559 
560 		dentptr = (dir_entry *)get_dentfromdir_block;
561 
562 		for (i = 0; i < DIRENTSPERCLUST; i++) {
563 			char s_name[14], l_name[VFAT_MAXLEN_BYTES];
564 
565 			l_name[0] = '\0';
566 			if (dentptr->name[0] == DELETED_FLAG) {
567 				dentptr++;
568 				continue;
569 			}
570 			if ((dentptr->attr & ATTR_VOLUME)) {
571 #ifdef CONFIG_SUPPORT_VFAT
572 				if ((dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
573 				    (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
574 					prevcksum = ((dir_slot *)dentptr)->alias_checksum;
575 					get_vfatname(mydata, curclust,
576 						     get_dentfromdir_block,
577 						     dentptr, l_name);
578 					if (dols) {
579 						int isdir;
580 						char dirc;
581 						int doit = 0;
582 
583 						isdir = (dentptr->attr & ATTR_DIR);
584 
585 						if (isdir) {
586 							dirs++;
587 							dirc = '/';
588 							doit = 1;
589 						} else {
590 							dirc = ' ';
591 							if (l_name[0] != 0) {
592 								files++;
593 								doit = 1;
594 							}
595 						}
596 						if (doit) {
597 							if (dirc == ' ') {
598 								printf(" %8ld   %s%c\n",
599 									(long)FAT2CPU32(dentptr->size),
600 									l_name,
601 									dirc);
602 							} else {
603 								printf("            %s%c\n",
604 									l_name,
605 									dirc);
606 							}
607 						}
608 						dentptr++;
609 						continue;
610 					}
611 					debug("vfatname: |%s|\n", l_name);
612 				} else
613 #endif
614 				{
615 					/* Volume label or VFAT entry */
616 					dentptr++;
617 					continue;
618 				}
619 			}
620 			if (dentptr->name[0] == 0) {
621 				if (dols) {
622 					printf("\n%d file(s), %d dir(s)\n\n",
623 						files, dirs);
624 				}
625 				debug("Dentname == NULL - %d\n", i);
626 				return NULL;
627 			}
628 #ifdef CONFIG_SUPPORT_VFAT
629 			if (dols && mkcksum(dentptr->name) == prevcksum) {
630 				prevcksum = 0xffff;
631 				dentptr++;
632 				continue;
633 			}
634 #endif
635 			get_name(dentptr, s_name);
636 			if (dols) {
637 				int isdir = (dentptr->attr & ATTR_DIR);
638 				char dirc;
639 				int doit = 0;
640 
641 				if (isdir) {
642 					dirs++;
643 					dirc = '/';
644 					doit = 1;
645 				} else {
646 					dirc = ' ';
647 					if (s_name[0] != 0) {
648 						files++;
649 						doit = 1;
650 					}
651 				}
652 
653 				if (doit) {
654 					if (dirc == ' ') {
655 						printf(" %8ld   %s%c\n",
656 							(long)FAT2CPU32(dentptr->size),
657 							s_name, dirc);
658 					} else {
659 						printf("            %s%c\n",
660 							s_name, dirc);
661 					}
662 				}
663 
664 				dentptr++;
665 				continue;
666 			}
667 
668 			if (strcmp(filename, s_name)
669 			    && strcmp(filename, l_name)) {
670 				debug("Mismatch: |%s|%s|\n", s_name, l_name);
671 				dentptr++;
672 				continue;
673 			}
674 
675 			memcpy(retdent, dentptr, sizeof(dir_entry));
676 
677 			debug("DentName: %s", s_name);
678 			debug(", start: 0x%x", START(dentptr));
679 			debug(", size:  0x%x %s\n",
680 			      FAT2CPU32(dentptr->size),
681 			      (dentptr->attr & ATTR_DIR) ? "(DIR)" : "");
682 
683 			return retdent;
684 		}
685 
686 		curclust = get_fatent(mydata, curclust);
687 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
688 			debug("curclust: 0x%x\n", curclust);
689 			printf("Invalid FAT entry\n");
690 			return NULL;
691 		}
692 	}
693 
694 	return NULL;
695 }
696 
697 /*
698  * Read boot sector and volume info from a FAT filesystem
699  */
700 static int
701 read_bootsectandvi (boot_sector *bs, volume_info *volinfo, int *fatsize)
702 {
703 	__u8 *block;
704 	volume_info *vistart;
705 	int ret = 0;
706 
707 	if (cur_dev == NULL) {
708 		debug("Error: no device selected\n");
709 		return -1;
710 	}
711 
712 	block = malloc(cur_dev->blksz);
713 	if (block == NULL) {
714 		debug("Error: allocating block\n");
715 		return -1;
716 	}
717 
718 	if (disk_read (0, 1, block) < 0) {
719 		debug("Error: reading block\n");
720 		goto fail;
721 	}
722 
723 	memcpy(bs, block, sizeof(boot_sector));
724 	bs->reserved = FAT2CPU16(bs->reserved);
725 	bs->fat_length = FAT2CPU16(bs->fat_length);
726 	bs->secs_track = FAT2CPU16(bs->secs_track);
727 	bs->heads = FAT2CPU16(bs->heads);
728 	bs->total_sect = FAT2CPU32(bs->total_sect);
729 
730 	/* FAT32 entries */
731 	if (bs->fat_length == 0) {
732 		/* Assume FAT32 */
733 		bs->fat32_length = FAT2CPU32(bs->fat32_length);
734 		bs->flags = FAT2CPU16(bs->flags);
735 		bs->root_cluster = FAT2CPU32(bs->root_cluster);
736 		bs->info_sector = FAT2CPU16(bs->info_sector);
737 		bs->backup_boot = FAT2CPU16(bs->backup_boot);
738 		vistart = (volume_info *)(block + sizeof(boot_sector));
739 		*fatsize = 32;
740 	} else {
741 		vistart = (volume_info *)&(bs->fat32_length);
742 		*fatsize = 0;
743 	}
744 	memcpy(volinfo, vistart, sizeof(volume_info));
745 
746 	if (*fatsize == 32) {
747 		if (strncmp(FAT32_SIGN, vistart->fs_type, SIGNLEN) == 0)
748 			goto exit;
749 	} else {
750 		if (strncmp(FAT12_SIGN, vistart->fs_type, SIGNLEN) == 0) {
751 			*fatsize = 12;
752 			goto exit;
753 		}
754 		if (strncmp(FAT16_SIGN, vistart->fs_type, SIGNLEN) == 0) {
755 			*fatsize = 16;
756 			goto exit;
757 		}
758 	}
759 
760 	debug("Error: broken fs_type sign\n");
761 fail:
762 	ret = -1;
763 exit:
764 	free(block);
765 	return ret;
766 }
767 
768 __attribute__ ((__aligned__ (__alignof__ (dir_entry))))
769 __u8 do_fat_read_block[MAX_CLUSTSIZE];
770 
771 long
772 do_fat_read (const char *filename, void *buffer, unsigned long maxsize,
773 	     int dols)
774 {
775 	char fnamecopy[2048];
776 	boot_sector bs;
777 	volume_info volinfo;
778 	fsdata datablock;
779 	fsdata *mydata = &datablock;
780 	dir_entry *dentptr;
781 	__u16 prevcksum = 0xffff;
782 	char *subname = "";
783 	__u32 cursect;
784 	int idx, isdir = 0;
785 	int files = 0, dirs = 0;
786 	long ret = -1;
787 	int firsttime;
788 	__u32 root_cluster = 0;
789 	int rootdir_size = 0;
790 	int j;
791 
792 	if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
793 		debug("Error: reading boot sector\n");
794 		return -1;
795 	}
796 
797 	if (mydata->fatsize == 32) {
798 		root_cluster = bs.root_cluster;
799 		mydata->fatlength = bs.fat32_length;
800 	} else {
801 		mydata->fatlength = bs.fat_length;
802 	}
803 
804 	mydata->fat_sect = bs.reserved;
805 
806 	cursect = mydata->rootdir_sect
807 		= mydata->fat_sect + mydata->fatlength * bs.fats;
808 
809 	mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
810 	mydata->clust_size = bs.cluster_size;
811 	if (mydata->sect_size != cur_part_info.blksz) {
812 		printf("Error: FAT sector size mismatch (fs=%hu, dev=%lu)\n",
813 				mydata->sect_size, cur_part_info.blksz);
814 		return -1;
815 	}
816 
817 	if (mydata->fatsize == 32) {
818 		mydata->data_begin = mydata->rootdir_sect -
819 					(mydata->clust_size * 2);
820 	} else {
821 		rootdir_size = ((bs.dir_entries[1]  * (int)256 +
822 				 bs.dir_entries[0]) *
823 				 sizeof(dir_entry)) /
824 				 mydata->sect_size;
825 		mydata->data_begin = mydata->rootdir_sect +
826 					rootdir_size -
827 					(mydata->clust_size * 2);
828 	}
829 
830 	mydata->fatbufnum = -1;
831 	mydata->fatbuf = malloc(FATBUFSIZE);
832 	if (mydata->fatbuf == NULL) {
833 		debug("Error: allocating memory\n");
834 		return -1;
835 	}
836 
837 #ifdef CONFIG_SUPPORT_VFAT
838 	debug("VFAT Support enabled\n");
839 #endif
840 	debug("FAT%d, fat_sect: %d, fatlength: %d\n",
841 	       mydata->fatsize, mydata->fat_sect, mydata->fatlength);
842 	debug("Rootdir begins at cluster: %d, sector: %d, offset: %x\n"
843 	       "Data begins at: %d\n",
844 	       root_cluster,
845 	       mydata->rootdir_sect,
846 	       mydata->rootdir_sect * mydata->sect_size, mydata->data_begin);
847 	debug("Sector size: %d, cluster size: %d\n", mydata->sect_size,
848 	      mydata->clust_size);
849 
850 	/* "cwd" is always the root... */
851 	while (ISDIRDELIM(*filename))
852 		filename++;
853 
854 	/* Make a copy of the filename and convert it to lowercase */
855 	strcpy(fnamecopy, filename);
856 	downcase(fnamecopy);
857 
858 	if (*fnamecopy == '\0') {
859 		if (!dols)
860 			goto exit;
861 
862 		dols = LS_ROOT;
863 	} else if ((idx = dirdelim(fnamecopy)) >= 0) {
864 		isdir = 1;
865 		fnamecopy[idx] = '\0';
866 		subname = fnamecopy + idx + 1;
867 
868 		/* Handle multiple delimiters */
869 		while (ISDIRDELIM(*subname))
870 			subname++;
871 	} else if (dols) {
872 		isdir = 1;
873 	}
874 
875 	j = 0;
876 	while (1) {
877 		int i;
878 
879 		debug("FAT read sect=%d, clust_size=%d, DIRENTSPERBLOCK=%zd\n",
880 			cursect, mydata->clust_size, DIRENTSPERBLOCK);
881 
882 		if (disk_read(cursect,
883 				(mydata->fatsize == 32) ?
884 				(mydata->clust_size) :
885 				PREFETCH_BLOCKS,
886 				do_fat_read_block) < 0) {
887 			debug("Error: reading rootdir block\n");
888 			goto exit;
889 		}
890 
891 		dentptr = (dir_entry *) do_fat_read_block;
892 
893 		for (i = 0; i < DIRENTSPERBLOCK; i++) {
894 			char s_name[14], l_name[VFAT_MAXLEN_BYTES];
895 
896 			l_name[0] = '\0';
897 			if (dentptr->name[0] == DELETED_FLAG) {
898 				dentptr++;
899 				continue;
900 			}
901 			if ((dentptr->attr & ATTR_VOLUME)) {
902 #ifdef CONFIG_SUPPORT_VFAT
903 				if ((dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
904 				    (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
905 					prevcksum =
906 						((dir_slot *)dentptr)->alias_checksum;
907 
908 					get_vfatname(mydata,
909 						     root_cluster,
910 						     do_fat_read_block,
911 						     dentptr, l_name);
912 
913 					if (dols == LS_ROOT) {
914 						char dirc;
915 						int doit = 0;
916 						int isdir =
917 							(dentptr->attr & ATTR_DIR);
918 
919 						if (isdir) {
920 							dirs++;
921 							dirc = '/';
922 							doit = 1;
923 						} else {
924 							dirc = ' ';
925 							if (l_name[0] != 0) {
926 								files++;
927 								doit = 1;
928 							}
929 						}
930 						if (doit) {
931 							if (dirc == ' ') {
932 								printf(" %8ld   %s%c\n",
933 									(long)FAT2CPU32(dentptr->size),
934 									l_name,
935 									dirc);
936 							} else {
937 								printf("            %s%c\n",
938 									l_name,
939 									dirc);
940 							}
941 						}
942 						dentptr++;
943 						continue;
944 					}
945 					debug("Rootvfatname: |%s|\n",
946 					       l_name);
947 				} else
948 #endif
949 				{
950 					/* Volume label or VFAT entry */
951 					dentptr++;
952 					continue;
953 				}
954 			} else if (dentptr->name[0] == 0) {
955 				debug("RootDentname == NULL - %d\n", i);
956 				if (dols == LS_ROOT) {
957 					printf("\n%d file(s), %d dir(s)\n\n",
958 						files, dirs);
959 					ret = 0;
960 				}
961 				goto exit;
962 			}
963 #ifdef CONFIG_SUPPORT_VFAT
964 			else if (dols == LS_ROOT &&
965 				 mkcksum(dentptr->name) == prevcksum) {
966 				prevcksum = 0xffff;
967 				dentptr++;
968 				continue;
969 			}
970 #endif
971 			get_name(dentptr, s_name);
972 
973 			if (dols == LS_ROOT) {
974 				int isdir = (dentptr->attr & ATTR_DIR);
975 				char dirc;
976 				int doit = 0;
977 
978 				if (isdir) {
979 					dirc = '/';
980 					if (s_name[0] != 0) {
981 						dirs++;
982 						doit = 1;
983 					}
984 				} else {
985 					dirc = ' ';
986 					if (s_name[0] != 0) {
987 						files++;
988 						doit = 1;
989 					}
990 				}
991 				if (doit) {
992 					if (dirc == ' ') {
993 						printf(" %8ld   %s%c\n",
994 							(long)FAT2CPU32(dentptr->size),
995 							s_name, dirc);
996 					} else {
997 						printf("            %s%c\n",
998 							s_name, dirc);
999 					}
1000 				}
1001 				dentptr++;
1002 				continue;
1003 			}
1004 
1005 			if (strcmp(fnamecopy, s_name)
1006 			    && strcmp(fnamecopy, l_name)) {
1007 				debug("RootMismatch: |%s|%s|\n", s_name,
1008 				       l_name);
1009 				dentptr++;
1010 				continue;
1011 			}
1012 
1013 			if (isdir && !(dentptr->attr & ATTR_DIR))
1014 				goto exit;
1015 
1016 			debug("RootName: %s", s_name);
1017 			debug(", start: 0x%x", START(dentptr));
1018 			debug(", size:  0x%x %s\n",
1019 			       FAT2CPU32(dentptr->size),
1020 			       isdir ? "(DIR)" : "");
1021 
1022 			goto rootdir_done;	/* We got a match */
1023 		}
1024 		debug("END LOOP: j=%d   clust_size=%d\n", j,
1025 		       mydata->clust_size);
1026 
1027 		/*
1028 		 * On FAT32 we must fetch the FAT entries for the next
1029 		 * root directory clusters when a cluster has been
1030 		 * completely processed.
1031 		 */
1032 		++j;
1033 		int fat32_end = 0;
1034 		if ((mydata->fatsize == 32) && (j == mydata->clust_size)) {
1035 			int nxtsect = 0;
1036 			int nxt_clust = 0;
1037 
1038 			nxt_clust = get_fatent(mydata, root_cluster);
1039 			fat32_end = CHECK_CLUST(nxt_clust, 32);
1040 
1041 			nxtsect = mydata->data_begin +
1042 				(nxt_clust * mydata->clust_size);
1043 
1044 			root_cluster = nxt_clust;
1045 
1046 			cursect = nxtsect;
1047 			j = 0;
1048 		} else {
1049 			cursect++;
1050 		}
1051 
1052 		/* If end of rootdir reached */
1053 		if ((mydata->fatsize == 32 && fat32_end) ||
1054 		    (mydata->fatsize != 32 && j == rootdir_size)) {
1055 			if (dols == LS_ROOT) {
1056 				printf("\n%d file(s), %d dir(s)\n\n",
1057 				       files, dirs);
1058 				ret = 0;
1059 			}
1060 			goto exit;
1061 		}
1062 	}
1063 rootdir_done:
1064 
1065 	firsttime = 1;
1066 
1067 	while (isdir) {
1068 		int startsect = mydata->data_begin
1069 			+ START(dentptr) * mydata->clust_size;
1070 		dir_entry dent;
1071 		char *nextname = NULL;
1072 
1073 		dent = *dentptr;
1074 		dentptr = &dent;
1075 
1076 		idx = dirdelim(subname);
1077 
1078 		if (idx >= 0) {
1079 			subname[idx] = '\0';
1080 			nextname = subname + idx + 1;
1081 			/* Handle multiple delimiters */
1082 			while (ISDIRDELIM(*nextname))
1083 				nextname++;
1084 			if (dols && *nextname == '\0')
1085 				firsttime = 0;
1086 		} else {
1087 			if (dols && firsttime) {
1088 				firsttime = 0;
1089 			} else {
1090 				isdir = 0;
1091 			}
1092 		}
1093 
1094 		if (get_dentfromdir(mydata, startsect, subname, dentptr,
1095 				     isdir ? 0 : dols) == NULL) {
1096 			if (dols && !isdir)
1097 				ret = 0;
1098 			goto exit;
1099 		}
1100 
1101 		if (idx >= 0) {
1102 			if (!(dentptr->attr & ATTR_DIR))
1103 				goto exit;
1104 			subname = nextname;
1105 		}
1106 	}
1107 
1108 	ret = get_contents(mydata, dentptr, buffer, maxsize);
1109 	debug("Size: %d, got: %ld\n", FAT2CPU32(dentptr->size), ret);
1110 
1111 exit:
1112 	free(mydata->fatbuf);
1113 	return ret;
1114 }
1115 
1116 int file_fat_detectfs (void)
1117 {
1118 	boot_sector bs;
1119 	volume_info volinfo;
1120 	int fatsize;
1121 	char vol_label[12];
1122 
1123 	if (cur_dev == NULL) {
1124 		printf("No current device\n");
1125 		return 1;
1126 	}
1127 
1128 #if defined(CONFIG_CMD_IDE) || \
1129     defined(CONFIG_CMD_MG_DISK) || \
1130     defined(CONFIG_CMD_SATA) || \
1131     defined(CONFIG_CMD_SCSI) || \
1132     defined(CONFIG_CMD_USB) || \
1133     defined(CONFIG_MMC)
1134 	printf("Interface:  ");
1135 	switch (cur_dev->if_type) {
1136 	case IF_TYPE_IDE:
1137 		printf("IDE");
1138 		break;
1139 	case IF_TYPE_SATA:
1140 		printf("SATA");
1141 		break;
1142 	case IF_TYPE_SCSI:
1143 		printf("SCSI");
1144 		break;
1145 	case IF_TYPE_ATAPI:
1146 		printf("ATAPI");
1147 		break;
1148 	case IF_TYPE_USB:
1149 		printf("USB");
1150 		break;
1151 	case IF_TYPE_DOC:
1152 		printf("DOC");
1153 		break;
1154 	case IF_TYPE_MMC:
1155 		printf("MMC");
1156 		break;
1157 	default:
1158 		printf("Unknown");
1159 	}
1160 
1161 	printf("\n  Device %d: ", cur_dev->dev);
1162 	dev_print(cur_dev);
1163 #endif
1164 
1165 	if (read_bootsectandvi(&bs, &volinfo, &fatsize)) {
1166 		printf("\nNo valid FAT fs found\n");
1167 		return 1;
1168 	}
1169 
1170 	memcpy(vol_label, volinfo.volume_label, 11);
1171 	vol_label[11] = '\0';
1172 	volinfo.fs_type[5] = '\0';
1173 
1174 	printf("Partition %d: Filesystem: %s \"%s\"\n", cur_part_nr,
1175 		volinfo.fs_type, vol_label);
1176 
1177 	return 0;
1178 }
1179 
1180 int file_fat_ls (const char *dir)
1181 {
1182 	return do_fat_read(dir, NULL, 0, LS_YES);
1183 }
1184 
1185 long file_fat_read (const char *filename, void *buffer, unsigned long maxsize)
1186 {
1187 	printf("reading %s\n", filename);
1188 	return do_fat_read(filename, buffer, maxsize, LS_NO);
1189 }
1190