xref: /openbmc/u-boot/fs/fat/fat.c (revision 0cb77bfa)
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 <fat.h>
31 #include <asm/byteorder.h>
32 #include <part.h>
33 
34 /*
35  * Convert a string to lowercase.
36  */
37 static void downcase (char *str)
38 {
39 	while (*str != '\0') {
40 		TOLOWER(*str);
41 		str++;
42 	}
43 }
44 
45 static block_dev_desc_t *cur_dev = NULL;
46 
47 static unsigned long part_offset = 0;
48 
49 static int cur_part = 1;
50 
51 #define DOS_PART_TBL_OFFSET	0x1be
52 #define DOS_PART_MAGIC_OFFSET	0x1fe
53 #define DOS_FS_TYPE_OFFSET	0x36
54 #define DOS_FS32_TYPE_OFFSET	0x52
55 
56 static int disk_read (__u32 startblock, __u32 getsize, __u8 * bufptr)
57 {
58 	if (cur_dev == NULL)
59 		return -1;
60 
61 	startblock += part_offset;
62 
63 	if (cur_dev->block_read) {
64 		return cur_dev->block_read(cur_dev->dev, startblock, getsize,
65 					   (unsigned long *) bufptr);
66 	}
67 	return -1;
68 }
69 
70 int fat_register_device (block_dev_desc_t * dev_desc, int part_no)
71 {
72 	unsigned char buffer[SECTOR_SIZE];
73 
74 	disk_partition_t info;
75 
76 	if (!dev_desc->block_read)
77 		return -1;
78 
79 	cur_dev = dev_desc;
80 	/* check if we have a MBR (on floppies we have only a PBR) */
81 	if (dev_desc->block_read(dev_desc->dev, 0, 1, (ulong *)buffer) != 1) {
82 		printf("** Can't read from device %d **\n",
83 			dev_desc->dev);
84 		return -1;
85 	}
86 	if (buffer[DOS_PART_MAGIC_OFFSET] != 0x55 ||
87 	    buffer[DOS_PART_MAGIC_OFFSET + 1] != 0xaa) {
88 		/* no signature found */
89 		return -1;
90 	}
91 #if (defined(CONFIG_CMD_IDE) || \
92      defined(CONFIG_CMD_MG_DISK) || \
93      defined(CONFIG_CMD_SATA) || \
94      defined(CONFIG_CMD_SCSI) || \
95      defined(CONFIG_CMD_USB) || \
96      defined(CONFIG_MMC) || \
97      defined(CONFIG_SYSTEMACE) )
98 	/* First we assume there is a MBR */
99 	if (!get_partition_info(dev_desc, part_no, &info)) {
100 		part_offset = info.start;
101 		cur_part = part_no;
102 	} else if ((strncmp((char *)&buffer[DOS_FS_TYPE_OFFSET], "FAT", 3) == 0) ||
103 		   (strncmp((char *)&buffer[DOS_FS32_TYPE_OFFSET], "FAT32", 5) == 0)) {
104 		/* ok, we assume we are on a PBR only */
105 		cur_part = 1;
106 		part_offset = 0;
107 	} else {
108 		printf("** Partition %d not valid on device %d **\n",
109 			part_no, dev_desc->dev);
110 		return -1;
111 	}
112 
113 #else
114 	if ((strncmp((char *)&buffer[DOS_FS_TYPE_OFFSET], "FAT", 3) == 0) ||
115 	    (strncmp((char *)&buffer[DOS_FS32_TYPE_OFFSET], "FAT32", 5) == 0)) {
116 		/* ok, we assume we are on a PBR only */
117 		cur_part = 1;
118 		part_offset = 0;
119 		info.start = part_offset;
120 	} else {
121 		/* FIXME we need to determine the start block of the
122 		 * partition where the DOS FS resides. This can be done
123 		 * by using the get_partition_info routine. For this
124 		 * purpose the libpart must be included.
125 		 */
126 		part_offset = 32;
127 		cur_part = 1;
128 	}
129 #endif
130 	return 0;
131 }
132 
133 /*
134  * Get the first occurence of a directory delimiter ('/' or '\') in a string.
135  * Return index into string if found, -1 otherwise.
136  */
137 static int dirdelim (char *str)
138 {
139 	char *start = str;
140 
141 	while (*str != '\0') {
142 		if (ISDIRDELIM(*str))
143 			return str - start;
144 		str++;
145 	}
146 	return -1;
147 }
148 
149 /*
150  * Extract zero terminated short name from a directory entry.
151  */
152 static void get_name (dir_entry *dirent, char *s_name)
153 {
154 	char *ptr;
155 
156 	memcpy(s_name, dirent->name, 8);
157 	s_name[8] = '\0';
158 	ptr = s_name;
159 	while (*ptr && *ptr != ' ')
160 		ptr++;
161 	if (dirent->ext[0] && dirent->ext[0] != ' ') {
162 		*ptr = '.';
163 		ptr++;
164 		memcpy(ptr, dirent->ext, 3);
165 		ptr[3] = '\0';
166 		while (*ptr && *ptr != ' ')
167 			ptr++;
168 	}
169 	*ptr = '\0';
170 	if (*s_name == DELETED_FLAG)
171 		*s_name = '\0';
172 	else if (*s_name == aRING)
173 		*s_name = DELETED_FLAG;
174 	downcase(s_name);
175 }
176 
177 /*
178  * Get the entry at index 'entry' in a FAT (12/16/32) table.
179  * On failure 0x00 is returned.
180  */
181 static __u32 get_fatent (fsdata *mydata, __u32 entry)
182 {
183 	__u32 bufnum;
184 	__u32 off16, offset;
185 	__u32 ret = 0x00;
186 	__u16 val1, val2;
187 
188 	switch (mydata->fatsize) {
189 	case 32:
190 		bufnum = entry / FAT32BUFSIZE;
191 		offset = entry - bufnum * FAT32BUFSIZE;
192 		break;
193 	case 16:
194 		bufnum = entry / FAT16BUFSIZE;
195 		offset = entry - bufnum * FAT16BUFSIZE;
196 		break;
197 	case 12:
198 		bufnum = entry / FAT12BUFSIZE;
199 		offset = entry - bufnum * FAT12BUFSIZE;
200 		break;
201 
202 	default:
203 		/* Unsupported FAT size */
204 		return ret;
205 	}
206 
207 	debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
208 	       mydata->fatsize, entry, entry, offset, offset);
209 
210 	/* Read a new block of FAT entries into the cache. */
211 	if (bufnum != mydata->fatbufnum) {
212 		__u32 getsize = FATBUFSIZE / FS_BLOCK_SIZE;
213 		__u8 *bufptr = mydata->fatbuf;
214 		__u32 fatlength = mydata->fatlength;
215 		__u32 startblock = bufnum * FATBUFBLOCKS;
216 
217 		fatlength *= SECTOR_SIZE;	/* We want it in bytes now */
218 		startblock += mydata->fat_sect;	/* Offset from start of disk */
219 
220 		if (getsize > fatlength)
221 			getsize = fatlength;
222 		if (disk_read(startblock, getsize, bufptr) < 0) {
223 			debug("Error reading FAT blocks\n");
224 			return ret;
225 		}
226 		mydata->fatbufnum = bufnum;
227 	}
228 
229 	/* Get the actual entry from the table */
230 	switch (mydata->fatsize) {
231 	case 32:
232 		ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
233 		break;
234 	case 16:
235 		ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
236 		break;
237 	case 12:
238 		off16 = (offset * 3) / 4;
239 
240 		switch (offset & 0x3) {
241 		case 0:
242 			ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[off16]);
243 			ret &= 0xfff;
244 			break;
245 		case 1:
246 			val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
247 			val1 &= 0xf000;
248 			val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
249 			val2 &= 0x00ff;
250 			ret = (val2 << 4) | (val1 >> 12);
251 			break;
252 		case 2:
253 			val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
254 			val1 &= 0xff00;
255 			val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
256 			val2 &= 0x000f;
257 			ret = (val2 << 8) | (val1 >> 8);
258 			break;
259 		case 3:
260 			ret = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
261 			ret = (ret & 0xfff0) >> 4;
262 			break;
263 		default:
264 			break;
265 		}
266 		break;
267 	}
268 	debug("FAT%d: ret: %08x, offset: %04x\n",
269 	       mydata->fatsize, ret, offset);
270 
271 	return ret;
272 }
273 
274 /*
275  * Read at most 'size' bytes from the specified cluster into 'buffer'.
276  * Return 0 on success, -1 otherwise.
277  */
278 static int
279 get_cluster (fsdata *mydata, __u32 clustnum, __u8 *buffer,
280 	     unsigned long size)
281 {
282 	__u32 idx = 0;
283 	__u32 startsect;
284 
285 	if (clustnum > 0) {
286 		startsect = mydata->data_begin +
287 				clustnum * mydata->clust_size;
288 	} else {
289 		startsect = mydata->rootdir_sect;
290 	}
291 
292 	debug("gc - clustnum: %d, startsect: %d\n", clustnum, startsect);
293 
294 	if (disk_read(startsect, size / FS_BLOCK_SIZE, buffer) < 0) {
295 		debug("Error reading data\n");
296 		return -1;
297 	}
298 	if (size % FS_BLOCK_SIZE) {
299 		__u8 tmpbuf[FS_BLOCK_SIZE];
300 
301 		idx = size / FS_BLOCK_SIZE;
302 		if (disk_read(startsect + idx, 1, tmpbuf) < 0) {
303 			debug("Error reading data\n");
304 			return -1;
305 		}
306 		buffer += idx * FS_BLOCK_SIZE;
307 
308 		memcpy(buffer, tmpbuf, size % FS_BLOCK_SIZE);
309 		return 0;
310 	}
311 
312 	return 0;
313 }
314 
315 /*
316  * Read at most 'maxsize' bytes from the file associated with 'dentptr'
317  * into 'buffer'.
318  * Return the number of bytes read or -1 on fatal errors.
319  */
320 static long
321 get_contents (fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
322 	      unsigned long maxsize)
323 {
324 	unsigned long filesize = FAT2CPU32(dentptr->size), gotsize = 0;
325 	unsigned int bytesperclust = mydata->clust_size * SECTOR_SIZE;
326 	__u32 curclust = START(dentptr);
327 	__u32 endclust, newclust;
328 	unsigned long actsize;
329 
330 	debug("Filesize: %ld bytes\n", filesize);
331 
332 	if (maxsize > 0 && filesize > maxsize)
333 		filesize = maxsize;
334 
335 	debug("%ld bytes\n", filesize);
336 
337 	actsize = bytesperclust;
338 	endclust = curclust;
339 
340 	do {
341 		/* search for consecutive clusters */
342 		while (actsize < filesize) {
343 			newclust = get_fatent(mydata, endclust);
344 			if ((newclust - 1) != endclust)
345 				goto getit;
346 			if (CHECK_CLUST(newclust, mydata->fatsize)) {
347 				debug("curclust: 0x%x\n", newclust);
348 				debug("Invalid FAT entry\n");
349 				return gotsize;
350 			}
351 			endclust = newclust;
352 			actsize += bytesperclust;
353 		}
354 
355 		/* actsize >= file size */
356 		actsize -= bytesperclust;
357 
358 		/* get remaining clusters */
359 		if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
360 			printf("Error reading cluster\n");
361 			return -1;
362 		}
363 
364 		/* get remaining bytes */
365 		gotsize += (int)actsize;
366 		filesize -= actsize;
367 		buffer += actsize;
368 		actsize = filesize;
369 		if (get_cluster(mydata, endclust, buffer, (int)actsize) != 0) {
370 			printf("Error reading cluster\n");
371 			return -1;
372 		}
373 		gotsize += actsize;
374 		return gotsize;
375 getit:
376 		if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
377 			printf("Error reading cluster\n");
378 			return -1;
379 		}
380 		gotsize += (int)actsize;
381 		filesize -= actsize;
382 		buffer += actsize;
383 
384 		curclust = get_fatent(mydata, endclust);
385 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
386 			debug("curclust: 0x%x\n", curclust);
387 			printf("Invalid FAT entry\n");
388 			return gotsize;
389 		}
390 		actsize = bytesperclust;
391 		endclust = curclust;
392 	} while (1);
393 }
394 
395 #ifdef CONFIG_SUPPORT_VFAT
396 /*
397  * Extract the file name information from 'slotptr' into 'l_name',
398  * starting at l_name[*idx].
399  * Return 1 if terminator (zero byte) is found, 0 otherwise.
400  */
401 static int slot2str (dir_slot *slotptr, char *l_name, int *idx)
402 {
403 	int j;
404 
405 	for (j = 0; j <= 8; j += 2) {
406 		l_name[*idx] = slotptr->name0_4[j];
407 		if (l_name[*idx] == 0x00)
408 			return 1;
409 		(*idx)++;
410 	}
411 	for (j = 0; j <= 10; j += 2) {
412 		l_name[*idx] = slotptr->name5_10[j];
413 		if (l_name[*idx] == 0x00)
414 			return 1;
415 		(*idx)++;
416 	}
417 	for (j = 0; j <= 2; j += 2) {
418 		l_name[*idx] = slotptr->name11_12[j];
419 		if (l_name[*idx] == 0x00)
420 			return 1;
421 		(*idx)++;
422 	}
423 
424 	return 0;
425 }
426 
427 /*
428  * Extract the full long filename starting at 'retdent' (which is really
429  * a slot) into 'l_name'. If successful also copy the real directory entry
430  * into 'retdent'
431  * Return 0 on success, -1 otherwise.
432  */
433 __attribute__ ((__aligned__ (__alignof__ (dir_entry))))
434 __u8 get_vfatname_block[MAX_CLUSTSIZE];
435 
436 static int
437 get_vfatname (fsdata *mydata, int curclust, __u8 *cluster,
438 	      dir_entry *retdent, char *l_name)
439 {
440 	dir_entry *realdent;
441 	dir_slot *slotptr = (dir_slot *)retdent;
442 	__u8 *buflimit = cluster + ((curclust == 0) ?
443 					LINEAR_PREFETCH_SIZE :
444 					(mydata->clust_size * SECTOR_SIZE)
445 				   );
446 	__u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
447 	int idx = 0;
448 
449 	if (counter > VFAT_MAXSEQ) {
450 		debug("Error: VFAT name is too long\n");
451 		return -1;
452 	}
453 
454 	while ((__u8 *)slotptr < buflimit) {
455 		if (counter == 0)
456 			break;
457 		if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
458 			return -1;
459 		slotptr++;
460 		counter--;
461 	}
462 
463 	if ((__u8 *)slotptr >= buflimit) {
464 		dir_slot *slotptr2;
465 
466 		if (curclust == 0)
467 			return -1;
468 		curclust = get_fatent(mydata, curclust);
469 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
470 			debug("curclust: 0x%x\n", curclust);
471 			printf("Invalid FAT entry\n");
472 			return -1;
473 		}
474 
475 		if (get_cluster(mydata, curclust, get_vfatname_block,
476 				mydata->clust_size * SECTOR_SIZE) != 0) {
477 			debug("Error: reading directory block\n");
478 			return -1;
479 		}
480 
481 		slotptr2 = (dir_slot *)get_vfatname_block;
482 		while (counter > 0) {
483 			if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
484 			    & 0xff) != counter)
485 				return -1;
486 			slotptr2++;
487 			counter--;
488 		}
489 
490 		/* Save the real directory entry */
491 		realdent = (dir_entry *)slotptr2;
492 		while ((__u8 *)slotptr2 > get_vfatname_block) {
493 			slotptr2--;
494 			slot2str(slotptr2, l_name, &idx);
495 		}
496 	} else {
497 		/* Save the real directory entry */
498 		realdent = (dir_entry *)slotptr;
499 	}
500 
501 	do {
502 		slotptr--;
503 		if (slot2str(slotptr, l_name, &idx))
504 			break;
505 	} while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
506 
507 	l_name[idx] = '\0';
508 	if (*l_name == DELETED_FLAG)
509 		*l_name = '\0';
510 	else if (*l_name == aRING)
511 		*l_name = DELETED_FLAG;
512 	downcase(l_name);
513 
514 	/* Return the real directory entry */
515 	memcpy(retdent, realdent, sizeof(dir_entry));
516 
517 	return 0;
518 }
519 
520 /* Calculate short name checksum */
521 static __u8 mkcksum (const char *str)
522 {
523 	int i;
524 
525 	__u8 ret = 0;
526 
527 	for (i = 0; i < 11; i++) {
528 		ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + str[i];
529 	}
530 
531 	return ret;
532 }
533 #endif	/* CONFIG_SUPPORT_VFAT */
534 
535 /*
536  * Get the directory entry associated with 'filename' from the directory
537  * starting at 'startsect'
538  */
539 __attribute__ ((__aligned__ (__alignof__ (dir_entry))))
540 __u8 get_dentfromdir_block[MAX_CLUSTSIZE];
541 
542 static dir_entry *get_dentfromdir (fsdata *mydata, int startsect,
543 				   char *filename, dir_entry *retdent,
544 				   int dols)
545 {
546 	__u16 prevcksum = 0xffff;
547 	__u32 curclust = START(retdent);
548 	int files = 0, dirs = 0;
549 
550 	debug("get_dentfromdir: %s\n", filename);
551 
552 	while (1) {
553 		dir_entry *dentptr;
554 
555 		int i;
556 
557 		if (get_cluster(mydata, curclust, get_dentfromdir_block,
558 				mydata->clust_size * SECTOR_SIZE) != 0) {
559 			debug("Error: reading directory block\n");
560 			return NULL;
561 		}
562 
563 		dentptr = (dir_entry *)get_dentfromdir_block;
564 
565 		for (i = 0; i < DIRENTSPERCLUST; i++) {
566 			char s_name[14], l_name[VFAT_MAXLEN_BYTES];
567 
568 			l_name[0] = '\0';
569 			if (dentptr->name[0] == DELETED_FLAG) {
570 				dentptr++;
571 				continue;
572 			}
573 			if ((dentptr->attr & ATTR_VOLUME)) {
574 #ifdef CONFIG_SUPPORT_VFAT
575 				if ((dentptr->attr & ATTR_VFAT) &&
576 				    (dentptr-> name[0] & LAST_LONG_ENTRY_MASK)) {
577 					prevcksum = ((dir_slot *)dentptr)->alias_checksum;
578 					get_vfatname(mydata, curclust,
579 						     get_dentfromdir_block,
580 						     dentptr, l_name);
581 					if (dols) {
582 						int isdir;
583 						char dirc;
584 						int doit = 0;
585 
586 						isdir = (dentptr->attr & ATTR_DIR);
587 
588 						if (isdir) {
589 							dirs++;
590 							dirc = '/';
591 							doit = 1;
592 						} else {
593 							dirc = ' ';
594 							if (l_name[0] != 0) {
595 								files++;
596 								doit = 1;
597 							}
598 						}
599 						if (doit) {
600 							if (dirc == ' ') {
601 								printf(" %8ld   %s%c\n",
602 									(long)FAT2CPU32(dentptr->size),
603 									l_name,
604 									dirc);
605 							} else {
606 								printf("            %s%c\n",
607 									l_name,
608 									dirc);
609 							}
610 						}
611 						dentptr++;
612 						continue;
613 					}
614 					debug("vfatname: |%s|\n", l_name);
615 				} else
616 #endif
617 				{
618 					/* Volume label or VFAT entry */
619 					dentptr++;
620 					continue;
621 				}
622 			}
623 			if (dentptr->name[0] == 0) {
624 				if (dols) {
625 					printf("\n%d file(s), %d dir(s)\n\n",
626 						files, dirs);
627 				}
628 				debug("Dentname == NULL - %d\n", i);
629 				return NULL;
630 			}
631 #ifdef CONFIG_SUPPORT_VFAT
632 			if (dols && mkcksum(dentptr->name) == prevcksum) {
633 				dentptr++;
634 				continue;
635 			}
636 #endif
637 			get_name(dentptr, s_name);
638 			if (dols) {
639 				int isdir = (dentptr->attr & ATTR_DIR);
640 				char dirc;
641 				int doit = 0;
642 
643 				if (isdir) {
644 					dirs++;
645 					dirc = '/';
646 					doit = 1;
647 				} else {
648 					dirc = ' ';
649 					if (s_name[0] != 0) {
650 						files++;
651 						doit = 1;
652 					}
653 				}
654 
655 				if (doit) {
656 					if (dirc == ' ') {
657 						printf(" %8ld   %s%c\n",
658 							(long)FAT2CPU32(dentptr->size),
659 							s_name, dirc);
660 					} else {
661 						printf("            %s%c\n",
662 							s_name, dirc);
663 					}
664 				}
665 
666 				dentptr++;
667 				continue;
668 			}
669 
670 			if (strcmp(filename, s_name)
671 			    && strcmp(filename, l_name)) {
672 				debug("Mismatch: |%s|%s|\n", s_name, l_name);
673 				dentptr++;
674 				continue;
675 			}
676 
677 			memcpy(retdent, dentptr, sizeof(dir_entry));
678 
679 			debug("DentName: %s", s_name);
680 			debug(", start: 0x%x", START(dentptr));
681 			debug(", size:  0x%x %s\n",
682 			      FAT2CPU32(dentptr->size),
683 			      (dentptr->attr & ATTR_DIR) ? "(DIR)" : "");
684 
685 			return retdent;
686 		}
687 
688 		curclust = get_fatent(mydata, curclust);
689 		if (CHECK_CLUST(curclust, mydata->fatsize)) {
690 			debug("curclust: 0x%x\n", curclust);
691 			printf("Invalid FAT entry\n");
692 			return NULL;
693 		}
694 	}
695 
696 	return NULL;
697 }
698 
699 /*
700  * Read boot sector and volume info from a FAT filesystem
701  */
702 static int
703 read_bootsectandvi (boot_sector *bs, volume_info *volinfo, int *fatsize)
704 {
705 	__u8 block[FS_BLOCK_SIZE];
706 
707 	volume_info *vistart;
708 
709 	if (disk_read (0, 1, block) < 0) {
710 		debug("Error: reading block\n");
711 		return -1;
712 	}
713 
714 	memcpy(bs, block, sizeof(boot_sector));
715 	bs->reserved = FAT2CPU16(bs->reserved);
716 	bs->fat_length = FAT2CPU16(bs->fat_length);
717 	bs->secs_track = FAT2CPU16(bs->secs_track);
718 	bs->heads = FAT2CPU16(bs->heads);
719 	bs->total_sect = FAT2CPU32(bs->total_sect);
720 
721 	/* FAT32 entries */
722 	if (bs->fat_length == 0) {
723 		/* Assume FAT32 */
724 		bs->fat32_length = FAT2CPU32(bs->fat32_length);
725 		bs->flags = FAT2CPU16(bs->flags);
726 		bs->root_cluster = FAT2CPU32(bs->root_cluster);
727 		bs->info_sector = FAT2CPU16(bs->info_sector);
728 		bs->backup_boot = FAT2CPU16(bs->backup_boot);
729 		vistart = (volume_info *)(block + sizeof(boot_sector));
730 		*fatsize = 32;
731 	} else {
732 		vistart = (volume_info *)&(bs->fat32_length);
733 		*fatsize = 0;
734 	}
735 	memcpy(volinfo, vistart, sizeof(volume_info));
736 
737 	if (*fatsize == 32) {
738 		if (strncmp(FAT32_SIGN, vistart->fs_type, SIGNLEN) == 0)
739 			return 0;
740 	} else {
741 		if (strncmp(FAT12_SIGN, vistart->fs_type, SIGNLEN) == 0) {
742 			*fatsize = 12;
743 			return 0;
744 		}
745 		if (strncmp(FAT16_SIGN, vistart->fs_type, SIGNLEN) == 0) {
746 			*fatsize = 16;
747 			return 0;
748 		}
749 	}
750 
751 	debug("Error: broken fs_type sign\n");
752 	return -1;
753 }
754 
755 __attribute__ ((__aligned__ (__alignof__ (dir_entry))))
756 __u8 do_fat_read_block[MAX_CLUSTSIZE];
757 
758 long
759 do_fat_read (const char *filename, void *buffer, unsigned long maxsize,
760 	     int dols)
761 {
762 	char fnamecopy[2048];
763 	boot_sector bs;
764 	volume_info volinfo;
765 	fsdata datablock;
766 	fsdata *mydata = &datablock;
767 	dir_entry *dentptr;
768 	__u16 prevcksum = 0xffff;
769 	char *subname = "";
770 	__u32 cursect;
771 	int idx, isdir = 0;
772 	int files = 0, dirs = 0;
773 	long ret = 0;
774 	int firsttime;
775 	__u32 root_cluster;
776 	int rootdir_size = 0;
777 	int j;
778 
779 	if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
780 		debug("Error: reading boot sector\n");
781 		return -1;
782 	}
783 
784 	root_cluster = bs.root_cluster;
785 
786 	if (mydata->fatsize == 32)
787 		mydata->fatlength = bs.fat32_length;
788 	else
789 		mydata->fatlength = bs.fat_length;
790 
791 	mydata->fat_sect = bs.reserved;
792 
793 	cursect = mydata->rootdir_sect
794 		= mydata->fat_sect + mydata->fatlength * bs.fats;
795 
796 	mydata->clust_size = bs.cluster_size;
797 
798 	if (mydata->fatsize == 32) {
799 		mydata->data_begin = mydata->rootdir_sect -
800 					(mydata->clust_size * 2);
801 	} else {
802 		rootdir_size = ((bs.dir_entries[1]  * (int)256 +
803 				 bs.dir_entries[0]) *
804 				 sizeof(dir_entry)) /
805 				 SECTOR_SIZE;
806 		mydata->data_begin = mydata->rootdir_sect +
807 					rootdir_size -
808 					(mydata->clust_size * 2);
809 	}
810 
811 	mydata->fatbufnum = -1;
812 
813 #ifdef CONFIG_SUPPORT_VFAT
814 	debug("VFAT Support enabled\n");
815 #endif
816 	debug("FAT%d, fat_sect: %d, fatlength: %d\n",
817 	       mydata->fatsize, mydata->fat_sect, mydata->fatlength);
818 	debug("Rootdir begins at cluster: %d, sector: %d, offset: %x\n"
819 	       "Data begins at: %d\n",
820 	       root_cluster,
821 	       mydata->rootdir_sect,
822 	       mydata->rootdir_sect * SECTOR_SIZE, mydata->data_begin);
823 	debug("Cluster size: %d\n", mydata->clust_size);
824 
825 	/* "cwd" is always the root... */
826 	while (ISDIRDELIM(*filename))
827 		filename++;
828 
829 	/* Make a copy of the filename and convert it to lowercase */
830 	strcpy(fnamecopy, filename);
831 	downcase(fnamecopy);
832 
833 	if (*fnamecopy == '\0') {
834 		if (!dols)
835 			return -1;
836 
837 		dols = LS_ROOT;
838 	} else if ((idx = dirdelim(fnamecopy)) >= 0) {
839 		isdir = 1;
840 		fnamecopy[idx] = '\0';
841 		subname = fnamecopy + idx + 1;
842 
843 		/* Handle multiple delimiters */
844 		while (ISDIRDELIM(*subname))
845 			subname++;
846 	} else if (dols) {
847 		isdir = 1;
848 	}
849 
850 	j = 0;
851 	while (1) {
852 		int i;
853 
854 		debug("FAT read sect=%d, clust_size=%d, DIRENTSPERBLOCK=%d\n",
855 			cursect, mydata->clust_size, DIRENTSPERBLOCK);
856 
857 		if (disk_read(cursect,
858 				(mydata->fatsize == 32) ?
859 				(mydata->clust_size) :
860 				LINEAR_PREFETCH_SIZE / SECTOR_SIZE,
861 				do_fat_read_block) < 0) {
862 			debug("Error: reading rootdir block\n");
863 			return -1;
864 		}
865 
866 		dentptr = (dir_entry *) do_fat_read_block;
867 
868 		for (i = 0; i < DIRENTSPERBLOCK; i++) {
869 			char s_name[14], l_name[VFAT_MAXLEN_BYTES];
870 
871 			l_name[0] = '\0';
872 			if (dentptr->name[0] == DELETED_FLAG) {
873 				dentptr++;
874 				continue;
875 			}
876 			if ((dentptr->attr & ATTR_VOLUME)) {
877 #ifdef CONFIG_SUPPORT_VFAT
878 				if ((dentptr->attr & ATTR_VFAT) &&
879 				    (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
880 					prevcksum =
881 						((dir_slot *)dentptr)->alias_checksum;
882 
883 					get_vfatname(mydata,
884 						     (mydata->fatsize == 32) ?
885 						     root_cluster :
886 						     0,
887 						     do_fat_read_block,
888 						     dentptr, l_name);
889 
890 					if (dols == LS_ROOT) {
891 						char dirc;
892 						int doit = 0;
893 						int isdir =
894 							(dentptr->attr & ATTR_DIR);
895 
896 						if (isdir) {
897 							dirs++;
898 							dirc = '/';
899 							doit = 1;
900 						} else {
901 							dirc = ' ';
902 							if (l_name[0] != 0) {
903 								files++;
904 								doit = 1;
905 							}
906 						}
907 						if (doit) {
908 							if (dirc == ' ') {
909 								printf(" %8ld   %s%c\n",
910 									(long)FAT2CPU32(dentptr->size),
911 									l_name,
912 									dirc);
913 							} else {
914 								printf("            %s%c\n",
915 									l_name,
916 									dirc);
917 							}
918 						}
919 						dentptr++;
920 						continue;
921 					}
922 					debug("Rootvfatname: |%s|\n",
923 					       l_name);
924 				} else
925 #endif
926 				{
927 					/* Volume label or VFAT entry */
928 					dentptr++;
929 					continue;
930 				}
931 			} else if (dentptr->name[0] == 0) {
932 				debug("RootDentname == NULL - %d\n", i);
933 				if (dols == LS_ROOT) {
934 					printf("\n%d file(s), %d dir(s)\n\n",
935 						files, dirs);
936 					return 0;
937 				}
938 				return -1;
939 			}
940 #ifdef CONFIG_SUPPORT_VFAT
941 			else if (dols == LS_ROOT &&
942 				 mkcksum(dentptr->name) == prevcksum) {
943 				dentptr++;
944 				continue;
945 			}
946 #endif
947 			get_name(dentptr, s_name);
948 
949 			if (dols == LS_ROOT) {
950 				int isdir = (dentptr->attr & ATTR_DIR);
951 				char dirc;
952 				int doit = 0;
953 
954 				if (isdir) {
955 					dirc = '/';
956 					if (s_name[0] != 0) {
957 						dirs++;
958 						doit = 1;
959 					}
960 				} else {
961 					dirc = ' ';
962 					if (s_name[0] != 0) {
963 						files++;
964 						doit = 1;
965 					}
966 				}
967 				if (doit) {
968 					if (dirc == ' ') {
969 						printf(" %8ld   %s%c\n",
970 							(long)FAT2CPU32(dentptr->size),
971 							s_name, dirc);
972 					} else {
973 						printf("            %s%c\n",
974 							s_name, dirc);
975 					}
976 				}
977 				dentptr++;
978 				continue;
979 			}
980 
981 			if (strcmp(fnamecopy, s_name)
982 			    && strcmp(fnamecopy, l_name)) {
983 				debug("RootMismatch: |%s|%s|\n", s_name,
984 				       l_name);
985 				dentptr++;
986 				continue;
987 			}
988 
989 			if (isdir && !(dentptr->attr & ATTR_DIR))
990 				return -1;
991 
992 			debug("RootName: %s", s_name);
993 			debug(", start: 0x%x", START(dentptr));
994 			debug(", size:  0x%x %s\n",
995 			       FAT2CPU32(dentptr->size),
996 			       isdir ? "(DIR)" : "");
997 
998 			goto rootdir_done;	/* We got a match */
999 		}
1000 		debug("END LOOP: j=%d   clust_size=%d\n", j,
1001 		       mydata->clust_size);
1002 
1003 		/*
1004 		 * On FAT32 we must fetch the FAT entries for the next
1005 		 * root directory clusters when a cluster has been
1006 		 * completely processed.
1007 		 */
1008 		++j;
1009 		int fat32_end = 0;
1010 		if ((mydata->fatsize == 32) && (j == mydata->clust_size)) {
1011 			int nxtsect = 0;
1012 			int nxt_clust = 0;
1013 
1014 			nxt_clust = get_fatent(mydata, root_cluster);
1015 			fat32_end = CHECK_CLUST(nxt_clust, 32);
1016 
1017 			nxtsect = mydata->data_begin +
1018 				(nxt_clust * mydata->clust_size);
1019 
1020 			root_cluster = nxt_clust;
1021 
1022 			cursect = nxtsect;
1023 			j = 0;
1024 		} else {
1025 			cursect++;
1026 		}
1027 
1028 		/* If end of rootdir reached */
1029 		if ((mydata->fatsize == 32 && fat32_end) ||
1030 		    (mydata->fatsize != 32 && j == rootdir_size)) {
1031 			if (dols == LS_ROOT) {
1032 				printf("\n%d file(s), %d dir(s)\n\n",
1033 				       files, dirs);
1034 				return 0;
1035 			} else {
1036 				return -1;
1037 			}
1038 		}
1039 	}
1040 rootdir_done:
1041 
1042 	firsttime = 1;
1043 
1044 	while (isdir) {
1045 		int startsect = mydata->data_begin
1046 			+ START(dentptr) * mydata->clust_size;
1047 		dir_entry dent;
1048 		char *nextname = NULL;
1049 
1050 		dent = *dentptr;
1051 		dentptr = &dent;
1052 
1053 		idx = dirdelim(subname);
1054 
1055 		if (idx >= 0) {
1056 			subname[idx] = '\0';
1057 			nextname = subname + idx + 1;
1058 			/* Handle multiple delimiters */
1059 			while (ISDIRDELIM(*nextname))
1060 				nextname++;
1061 			if (dols && *nextname == '\0')
1062 				firsttime = 0;
1063 		} else {
1064 			if (dols && firsttime) {
1065 				firsttime = 0;
1066 			} else {
1067 				isdir = 0;
1068 			}
1069 		}
1070 
1071 		if (get_dentfromdir(mydata, startsect, subname, dentptr,
1072 				     isdir ? 0 : dols) == NULL) {
1073 			if (dols && !isdir)
1074 				return 0;
1075 			return -1;
1076 		}
1077 
1078 		if (idx >= 0) {
1079 			if (!(dentptr->attr & ATTR_DIR))
1080 				return -1;
1081 			subname = nextname;
1082 		}
1083 	}
1084 
1085 	ret = get_contents(mydata, dentptr, buffer, maxsize);
1086 	debug("Size: %d, got: %ld\n", FAT2CPU32(dentptr->size), ret);
1087 
1088 	return ret;
1089 }
1090 
1091 int file_fat_detectfs (void)
1092 {
1093 	boot_sector bs;
1094 	volume_info volinfo;
1095 	int fatsize;
1096 	char vol_label[12];
1097 
1098 	if (cur_dev == NULL) {
1099 		printf("No current device\n");
1100 		return 1;
1101 	}
1102 
1103 #if defined(CONFIG_CMD_IDE) || \
1104     defined(CONFIG_CMD_MG_DISK) || \
1105     defined(CONFIG_CMD_SATA) || \
1106     defined(CONFIG_CMD_SCSI) || \
1107     defined(CONFIG_CMD_USB) || \
1108     defined(CONFIG_MMC)
1109 	printf("Interface:  ");
1110 	switch (cur_dev->if_type) {
1111 	case IF_TYPE_IDE:
1112 		printf("IDE");
1113 		break;
1114 	case IF_TYPE_SATA:
1115 		printf("SATA");
1116 		break;
1117 	case IF_TYPE_SCSI:
1118 		printf("SCSI");
1119 		break;
1120 	case IF_TYPE_ATAPI:
1121 		printf("ATAPI");
1122 		break;
1123 	case IF_TYPE_USB:
1124 		printf("USB");
1125 		break;
1126 	case IF_TYPE_DOC:
1127 		printf("DOC");
1128 		break;
1129 	case IF_TYPE_MMC:
1130 		printf("MMC");
1131 		break;
1132 	default:
1133 		printf("Unknown");
1134 	}
1135 
1136 	printf("\n  Device %d: ", cur_dev->dev);
1137 	dev_print(cur_dev);
1138 #endif
1139 
1140 	if (read_bootsectandvi(&bs, &volinfo, &fatsize)) {
1141 		printf("\nNo valid FAT fs found\n");
1142 		return 1;
1143 	}
1144 
1145 	memcpy(vol_label, volinfo.volume_label, 11);
1146 	vol_label[11] = '\0';
1147 	volinfo.fs_type[5] = '\0';
1148 
1149 	printf("Partition %d: Filesystem: %s \"%s\"\n", cur_part,
1150 		volinfo.fs_type, vol_label);
1151 
1152 	return 0;
1153 }
1154 
1155 int file_fat_ls (const char *dir)
1156 {
1157 	return do_fat_read(dir, NULL, 0, LS_YES);
1158 }
1159 
1160 long file_fat_read (const char *filename, void *buffer, unsigned long maxsize)
1161 {
1162 	printf("reading %s\n", filename);
1163 	return do_fat_read(filename, buffer, maxsize, LS_NO);
1164 }
1165