xref: /openbmc/u-boot/fs/fat/fat.c (revision 24b852a7a2b8eca71789100983bdb5104cc00696)
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   * SPDX-License-Identifier:	GPL-2.0+
10   */
11  
12  #include <common.h>
13  #include <config.h>
14  #include <exports.h>
15  #include <fat.h>
16  #include <asm/byteorder.h>
17  #include <part.h>
18  #include <malloc.h>
19  #include <memalign.h>
20  #include <linux/compiler.h>
21  #include <linux/ctype.h>
22  
23  #ifdef CONFIG_SUPPORT_VFAT
24  static const int vfat_enabled = 1;
25  #else
26  static const int vfat_enabled = 0;
27  #endif
28  
29  /*
30   * Convert a string to lowercase.
31   */
32  static void downcase(char *str)
33  {
34  	while (*str != '\0') {
35  		*str = tolower(*str);
36  		str++;
37  	}
38  }
39  
40  static block_dev_desc_t *cur_dev;
41  static disk_partition_t cur_part_info;
42  
43  #define DOS_BOOT_MAGIC_OFFSET	0x1fe
44  #define DOS_FS_TYPE_OFFSET	0x36
45  #define DOS_FS32_TYPE_OFFSET	0x52
46  
47  static int disk_read(__u32 block, __u32 nr_blocks, void *buf)
48  {
49  	ulong ret;
50  
51  	if (!cur_dev || !cur_dev->block_read)
52  		return -1;
53  
54  	ret = cur_dev->block_read(cur_dev->dev,
55  				  cur_part_info.start + block, nr_blocks, buf);
56  
57  	if (nr_blocks && ret == 0)
58  		return -1;
59  
60  	return ret;
61  }
62  
63  int fat_set_blk_dev(block_dev_desc_t *dev_desc, disk_partition_t *info)
64  {
65  	ALLOC_CACHE_ALIGN_BUFFER(unsigned char, buffer, dev_desc->blksz);
66  
67  	cur_dev = dev_desc;
68  	cur_part_info = *info;
69  
70  	/* Make sure it has a valid FAT header */
71  	if (disk_read(0, 1, buffer) != 1) {
72  		cur_dev = NULL;
73  		return -1;
74  	}
75  
76  	/* Check if it's actually a DOS volume */
77  	if (memcmp(buffer + DOS_BOOT_MAGIC_OFFSET, "\x55\xAA", 2)) {
78  		cur_dev = NULL;
79  		return -1;
80  	}
81  
82  	/* Check for FAT12/FAT16/FAT32 filesystem */
83  	if (!memcmp(buffer + DOS_FS_TYPE_OFFSET, "FAT", 3))
84  		return 0;
85  	if (!memcmp(buffer + DOS_FS32_TYPE_OFFSET, "FAT32", 5))
86  		return 0;
87  
88  	cur_dev = NULL;
89  	return -1;
90  }
91  
92  int fat_register_device(block_dev_desc_t *dev_desc, int part_no)
93  {
94  	disk_partition_t info;
95  
96  	/* First close any currently found FAT filesystem */
97  	cur_dev = NULL;
98  
99  	/* Read the partition table, if present */
100  	if (get_partition_info(dev_desc, part_no, &info)) {
101  		if (part_no != 0) {
102  			printf("** Partition %d not valid on device %d **\n",
103  					part_no, dev_desc->dev);
104  			return -1;
105  		}
106  
107  		info.start = 0;
108  		info.size = dev_desc->lba;
109  		info.blksz = dev_desc->blksz;
110  		info.name[0] = 0;
111  		info.type[0] = 0;
112  		info.bootable = 0;
113  #ifdef CONFIG_PARTITION_UUIDS
114  		info.uuid[0] = 0;
115  #endif
116  	}
117  
118  	return fat_set_blk_dev(dev_desc, &info);
119  }
120  
121  /*
122   * Get the first occurence of a directory delimiter ('/' or '\') in a string.
123   * Return index into string if found, -1 otherwise.
124   */
125  static int dirdelim(char *str)
126  {
127  	char *start = str;
128  
129  	while (*str != '\0') {
130  		if (ISDIRDELIM(*str))
131  			return str - start;
132  		str++;
133  	}
134  	return -1;
135  }
136  
137  /*
138   * Extract zero terminated short name from a directory entry.
139   */
140  static void get_name(dir_entry *dirent, char *s_name)
141  {
142  	char *ptr;
143  
144  	memcpy(s_name, dirent->name, 8);
145  	s_name[8] = '\0';
146  	ptr = s_name;
147  	while (*ptr && *ptr != ' ')
148  		ptr++;
149  	if (dirent->ext[0] && dirent->ext[0] != ' ') {
150  		*ptr = '.';
151  		ptr++;
152  		memcpy(ptr, dirent->ext, 3);
153  		ptr[3] = '\0';
154  		while (*ptr && *ptr != ' ')
155  			ptr++;
156  	}
157  	*ptr = '\0';
158  	if (*s_name == DELETED_FLAG)
159  		*s_name = '\0';
160  	else if (*s_name == aRING)
161  		*s_name = DELETED_FLAG;
162  	downcase(s_name);
163  }
164  
165  /*
166   * Get the entry at index 'entry' in a FAT (12/16/32) table.
167   * On failure 0x00 is returned.
168   */
169  static __u32 get_fatent(fsdata *mydata, __u32 entry)
170  {
171  	__u32 bufnum;
172  	__u32 off16, offset;
173  	__u32 ret = 0x00;
174  	__u16 val1, val2;
175  
176  	switch (mydata->fatsize) {
177  	case 32:
178  		bufnum = entry / FAT32BUFSIZE;
179  		offset = entry - bufnum * FAT32BUFSIZE;
180  		break;
181  	case 16:
182  		bufnum = entry / FAT16BUFSIZE;
183  		offset = entry - bufnum * FAT16BUFSIZE;
184  		break;
185  	case 12:
186  		bufnum = entry / FAT12BUFSIZE;
187  		offset = entry - bufnum * FAT12BUFSIZE;
188  		break;
189  
190  	default:
191  		/* Unsupported FAT size */
192  		return ret;
193  	}
194  
195  	debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
196  	       mydata->fatsize, entry, entry, offset, offset);
197  
198  	/* Read a new block of FAT entries into the cache. */
199  	if (bufnum != mydata->fatbufnum) {
200  		__u32 getsize = FATBUFBLOCKS;
201  		__u8 *bufptr = mydata->fatbuf;
202  		__u32 fatlength = mydata->fatlength;
203  		__u32 startblock = bufnum * FATBUFBLOCKS;
204  
205  		if (startblock + getsize > fatlength)
206  			getsize = fatlength - startblock;
207  
208  		startblock += mydata->fat_sect;	/* Offset from start of disk */
209  
210  		if (disk_read(startblock, getsize, bufptr) < 0) {
211  			debug("Error reading FAT blocks\n");
212  			return ret;
213  		}
214  		mydata->fatbufnum = bufnum;
215  	}
216  
217  	/* Get the actual entry from the table */
218  	switch (mydata->fatsize) {
219  	case 32:
220  		ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
221  		break;
222  	case 16:
223  		ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
224  		break;
225  	case 12:
226  		off16 = (offset * 3) / 4;
227  
228  		switch (offset & 0x3) {
229  		case 0:
230  			ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[off16]);
231  			ret &= 0xfff;
232  			break;
233  		case 1:
234  			val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
235  			val1 &= 0xf000;
236  			val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
237  			val2 &= 0x00ff;
238  			ret = (val2 << 4) | (val1 >> 12);
239  			break;
240  		case 2:
241  			val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
242  			val1 &= 0xff00;
243  			val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
244  			val2 &= 0x000f;
245  			ret = (val2 << 8) | (val1 >> 8);
246  			break;
247  		case 3:
248  			ret = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
249  			ret = (ret & 0xfff0) >> 4;
250  			break;
251  		default:
252  			break;
253  		}
254  		break;
255  	}
256  	debug("FAT%d: ret: %08x, offset: %04x\n",
257  	       mydata->fatsize, ret, offset);
258  
259  	return ret;
260  }
261  
262  /*
263   * Read at most 'size' bytes from the specified cluster into 'buffer'.
264   * Return 0 on success, -1 otherwise.
265   */
266  static int
267  get_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer, unsigned long size)
268  {
269  	__u32 idx = 0;
270  	__u32 startsect;
271  	int ret;
272  
273  	if (clustnum > 0) {
274  		startsect = mydata->data_begin +
275  				clustnum * mydata->clust_size;
276  	} else {
277  		startsect = mydata->rootdir_sect;
278  	}
279  
280  	debug("gc - clustnum: %d, startsect: %d\n", clustnum, startsect);
281  
282  	if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
283  		ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
284  
285  		printf("FAT: Misaligned buffer address (%p)\n", buffer);
286  
287  		while (size >= mydata->sect_size) {
288  			ret = disk_read(startsect++, 1, tmpbuf);
289  			if (ret != 1) {
290  				debug("Error reading data (got %d)\n", ret);
291  				return -1;
292  			}
293  
294  			memcpy(buffer, tmpbuf, mydata->sect_size);
295  			buffer += mydata->sect_size;
296  			size -= mydata->sect_size;
297  		}
298  	} else {
299  		idx = size / mydata->sect_size;
300  		ret = disk_read(startsect, idx, buffer);
301  		if (ret != idx) {
302  			debug("Error reading data (got %d)\n", ret);
303  			return -1;
304  		}
305  		startsect += idx;
306  		idx *= mydata->sect_size;
307  		buffer += idx;
308  		size -= idx;
309  	}
310  	if (size) {
311  		ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
312  
313  		ret = disk_read(startsect, 1, tmpbuf);
314  		if (ret != 1) {
315  			debug("Error reading data (got %d)\n", ret);
316  			return -1;
317  		}
318  
319  		memcpy(buffer, tmpbuf, size);
320  	}
321  
322  	return 0;
323  }
324  
325  /*
326   * Read at most 'maxsize' bytes from 'pos' in the file associated with 'dentptr'
327   * into 'buffer'.
328   * Update the number of bytes read in *gotsize or return -1 on fatal errors.
329   */
330  __u8 get_contents_vfatname_block[MAX_CLUSTSIZE]
331  	__aligned(ARCH_DMA_MINALIGN);
332  
333  static int get_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos,
334  			__u8 *buffer, loff_t maxsize, loff_t *gotsize)
335  {
336  	loff_t filesize = FAT2CPU32(dentptr->size);
337  	unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
338  	__u32 curclust = START(dentptr);
339  	__u32 endclust, newclust;
340  	loff_t actsize;
341  
342  	*gotsize = 0;
343  	debug("Filesize: %llu bytes\n", filesize);
344  
345  	if (pos >= filesize) {
346  		debug("Read position past EOF: %llu\n", pos);
347  		return 0;
348  	}
349  
350  	if (maxsize > 0 && filesize > pos + maxsize)
351  		filesize = pos + maxsize;
352  
353  	debug("%llu bytes\n", filesize);
354  
355  	actsize = bytesperclust;
356  
357  	/* go to cluster at pos */
358  	while (actsize <= pos) {
359  		curclust = get_fatent(mydata, curclust);
360  		if (CHECK_CLUST(curclust, mydata->fatsize)) {
361  			debug("curclust: 0x%x\n", curclust);
362  			debug("Invalid FAT entry\n");
363  			return 0;
364  		}
365  		actsize += bytesperclust;
366  	}
367  
368  	/* actsize > pos */
369  	actsize -= bytesperclust;
370  	filesize -= actsize;
371  	pos -= actsize;
372  
373  	/* align to beginning of next cluster if any */
374  	if (pos) {
375  		actsize = min(filesize, (loff_t)bytesperclust);
376  		if (get_cluster(mydata, curclust, get_contents_vfatname_block,
377  				(int)actsize) != 0) {
378  			printf("Error reading cluster\n");
379  			return -1;
380  		}
381  		filesize -= actsize;
382  		actsize -= pos;
383  		memcpy(buffer, get_contents_vfatname_block + pos, actsize);
384  		*gotsize += actsize;
385  		if (!filesize)
386  			return 0;
387  		buffer += actsize;
388  
389  		curclust = get_fatent(mydata, curclust);
390  		if (CHECK_CLUST(curclust, mydata->fatsize)) {
391  			debug("curclust: 0x%x\n", curclust);
392  			debug("Invalid FAT entry\n");
393  			return 0;
394  		}
395  	}
396  
397  	actsize = bytesperclust;
398  	endclust = curclust;
399  
400  	do {
401  		/* search for consecutive clusters */
402  		while (actsize < filesize) {
403  			newclust = get_fatent(mydata, endclust);
404  			if ((newclust - 1) != endclust)
405  				goto getit;
406  			if (CHECK_CLUST(newclust, mydata->fatsize)) {
407  				debug("curclust: 0x%x\n", newclust);
408  				debug("Invalid FAT entry\n");
409  				return 0;
410  			}
411  			endclust = newclust;
412  			actsize += bytesperclust;
413  		}
414  
415  		/* get remaining bytes */
416  		actsize = filesize;
417  		if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
418  			printf("Error reading cluster\n");
419  			return -1;
420  		}
421  		*gotsize += actsize;
422  		return 0;
423  getit:
424  		if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
425  			printf("Error reading cluster\n");
426  			return -1;
427  		}
428  		*gotsize += (int)actsize;
429  		filesize -= actsize;
430  		buffer += actsize;
431  
432  		curclust = get_fatent(mydata, endclust);
433  		if (CHECK_CLUST(curclust, mydata->fatsize)) {
434  			debug("curclust: 0x%x\n", curclust);
435  			printf("Invalid FAT entry\n");
436  			return 0;
437  		}
438  		actsize = bytesperclust;
439  		endclust = curclust;
440  	} while (1);
441  }
442  
443  /*
444   * Extract the file name information from 'slotptr' into 'l_name',
445   * starting at l_name[*idx].
446   * Return 1 if terminator (zero byte) is found, 0 otherwise.
447   */
448  static int slot2str(dir_slot *slotptr, char *l_name, int *idx)
449  {
450  	int j;
451  
452  	for (j = 0; j <= 8; j += 2) {
453  		l_name[*idx] = slotptr->name0_4[j];
454  		if (l_name[*idx] == 0x00)
455  			return 1;
456  		(*idx)++;
457  	}
458  	for (j = 0; j <= 10; j += 2) {
459  		l_name[*idx] = slotptr->name5_10[j];
460  		if (l_name[*idx] == 0x00)
461  			return 1;
462  		(*idx)++;
463  	}
464  	for (j = 0; j <= 2; j += 2) {
465  		l_name[*idx] = slotptr->name11_12[j];
466  		if (l_name[*idx] == 0x00)
467  			return 1;
468  		(*idx)++;
469  	}
470  
471  	return 0;
472  }
473  
474  /*
475   * Extract the full long filename starting at 'retdent' (which is really
476   * a slot) into 'l_name'. If successful also copy the real directory entry
477   * into 'retdent'
478   * Return 0 on success, -1 otherwise.
479   */
480  static int
481  get_vfatname(fsdata *mydata, int curclust, __u8 *cluster,
482  	     dir_entry *retdent, char *l_name)
483  {
484  	dir_entry *realdent;
485  	dir_slot *slotptr = (dir_slot *)retdent;
486  	__u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
487  							PREFETCH_BLOCKS :
488  							mydata->clust_size);
489  	__u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
490  	int idx = 0;
491  
492  	if (counter > VFAT_MAXSEQ) {
493  		debug("Error: VFAT name is too long\n");
494  		return -1;
495  	}
496  
497  	while ((__u8 *)slotptr < buflimit) {
498  		if (counter == 0)
499  			break;
500  		if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
501  			return -1;
502  		slotptr++;
503  		counter--;
504  	}
505  
506  	if ((__u8 *)slotptr >= buflimit) {
507  		dir_slot *slotptr2;
508  
509  		if (curclust == 0)
510  			return -1;
511  		curclust = get_fatent(mydata, curclust);
512  		if (CHECK_CLUST(curclust, mydata->fatsize)) {
513  			debug("curclust: 0x%x\n", curclust);
514  			printf("Invalid FAT entry\n");
515  			return -1;
516  		}
517  
518  		if (get_cluster(mydata, curclust, get_contents_vfatname_block,
519  				mydata->clust_size * mydata->sect_size) != 0) {
520  			debug("Error: reading directory block\n");
521  			return -1;
522  		}
523  
524  		slotptr2 = (dir_slot *)get_contents_vfatname_block;
525  		while (counter > 0) {
526  			if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
527  			    & 0xff) != counter)
528  				return -1;
529  			slotptr2++;
530  			counter--;
531  		}
532  
533  		/* Save the real directory entry */
534  		realdent = (dir_entry *)slotptr2;
535  		while ((__u8 *)slotptr2 > get_contents_vfatname_block) {
536  			slotptr2--;
537  			slot2str(slotptr2, l_name, &idx);
538  		}
539  	} else {
540  		/* Save the real directory entry */
541  		realdent = (dir_entry *)slotptr;
542  	}
543  
544  	do {
545  		slotptr--;
546  		if (slot2str(slotptr, l_name, &idx))
547  			break;
548  	} while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
549  
550  	l_name[idx] = '\0';
551  	if (*l_name == DELETED_FLAG)
552  		*l_name = '\0';
553  	else if (*l_name == aRING)
554  		*l_name = DELETED_FLAG;
555  	downcase(l_name);
556  
557  	/* Return the real directory entry */
558  	memcpy(retdent, realdent, sizeof(dir_entry));
559  
560  	return 0;
561  }
562  
563  /* Calculate short name checksum */
564  static __u8 mkcksum(const char name[8], const char ext[3])
565  {
566  	int i;
567  
568  	__u8 ret = 0;
569  
570  	for (i = 0; i < 8; i++)
571  		ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + name[i];
572  	for (i = 0; i < 3; i++)
573  		ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + ext[i];
574  
575  	return ret;
576  }
577  
578  /*
579   * Get the directory entry associated with 'filename' from the directory
580   * starting at 'startsect'
581   */
582  __u8 get_dentfromdir_block[MAX_CLUSTSIZE]
583  	__aligned(ARCH_DMA_MINALIGN);
584  
585  static dir_entry *get_dentfromdir(fsdata *mydata, int startsect,
586  				  char *filename, dir_entry *retdent,
587  				  int dols)
588  {
589  	__u16 prevcksum = 0xffff;
590  	__u32 curclust = START(retdent);
591  	int files = 0, dirs = 0;
592  
593  	debug("get_dentfromdir: %s\n", filename);
594  
595  	while (1) {
596  		dir_entry *dentptr;
597  
598  		int i;
599  
600  		if (get_cluster(mydata, curclust, get_dentfromdir_block,
601  				mydata->clust_size * mydata->sect_size) != 0) {
602  			debug("Error: reading directory block\n");
603  			return NULL;
604  		}
605  
606  		dentptr = (dir_entry *)get_dentfromdir_block;
607  
608  		for (i = 0; i < DIRENTSPERCLUST; i++) {
609  			char s_name[14], l_name[VFAT_MAXLEN_BYTES];
610  
611  			l_name[0] = '\0';
612  			if (dentptr->name[0] == DELETED_FLAG) {
613  				dentptr++;
614  				continue;
615  			}
616  			if ((dentptr->attr & ATTR_VOLUME)) {
617  				if (vfat_enabled &&
618  				    (dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
619  				    (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
620  					prevcksum = ((dir_slot *)dentptr)->alias_checksum;
621  					get_vfatname(mydata, curclust,
622  						     get_dentfromdir_block,
623  						     dentptr, l_name);
624  					if (dols) {
625  						int isdir;
626  						char dirc;
627  						int doit = 0;
628  
629  						isdir = (dentptr->attr & ATTR_DIR);
630  
631  						if (isdir) {
632  							dirs++;
633  							dirc = '/';
634  							doit = 1;
635  						} else {
636  							dirc = ' ';
637  							if (l_name[0] != 0) {
638  								files++;
639  								doit = 1;
640  							}
641  						}
642  						if (doit) {
643  							if (dirc == ' ') {
644  								printf(" %8u   %s%c\n",
645  								       FAT2CPU32(dentptr->size),
646  									l_name,
647  									dirc);
648  							} else {
649  								printf("            %s%c\n",
650  									l_name,
651  									dirc);
652  							}
653  						}
654  						dentptr++;
655  						continue;
656  					}
657  					debug("vfatname: |%s|\n", l_name);
658  				} else {
659  					/* Volume label or VFAT entry */
660  					dentptr++;
661  					continue;
662  				}
663  			}
664  			if (dentptr->name[0] == 0) {
665  				if (dols) {
666  					printf("\n%d file(s), %d dir(s)\n\n",
667  						files, dirs);
668  				}
669  				debug("Dentname == NULL - %d\n", i);
670  				return NULL;
671  			}
672  			if (vfat_enabled) {
673  				__u8 csum = mkcksum(dentptr->name, dentptr->ext);
674  				if (dols && csum == prevcksum) {
675  					prevcksum = 0xffff;
676  					dentptr++;
677  					continue;
678  				}
679  			}
680  
681  			get_name(dentptr, s_name);
682  			if (dols) {
683  				int isdir = (dentptr->attr & ATTR_DIR);
684  				char dirc;
685  				int doit = 0;
686  
687  				if (isdir) {
688  					dirs++;
689  					dirc = '/';
690  					doit = 1;
691  				} else {
692  					dirc = ' ';
693  					if (s_name[0] != 0) {
694  						files++;
695  						doit = 1;
696  					}
697  				}
698  
699  				if (doit) {
700  					if (dirc == ' ') {
701  						printf(" %8u   %s%c\n",
702  						       FAT2CPU32(dentptr->size),
703  							s_name, dirc);
704  					} else {
705  						printf("            %s%c\n",
706  							s_name, dirc);
707  					}
708  				}
709  
710  				dentptr++;
711  				continue;
712  			}
713  
714  			if (strcmp(filename, s_name)
715  			    && strcmp(filename, l_name)) {
716  				debug("Mismatch: |%s|%s|\n", s_name, l_name);
717  				dentptr++;
718  				continue;
719  			}
720  
721  			memcpy(retdent, dentptr, sizeof(dir_entry));
722  
723  			debug("DentName: %s", s_name);
724  			debug(", start: 0x%x", START(dentptr));
725  			debug(", size:  0x%x %s\n",
726  			      FAT2CPU32(dentptr->size),
727  			      (dentptr->attr & ATTR_DIR) ? "(DIR)" : "");
728  
729  			return retdent;
730  		}
731  
732  		curclust = get_fatent(mydata, curclust);
733  		if (CHECK_CLUST(curclust, mydata->fatsize)) {
734  			debug("curclust: 0x%x\n", curclust);
735  			printf("Invalid FAT entry\n");
736  			return NULL;
737  		}
738  	}
739  
740  	return NULL;
741  }
742  
743  /*
744   * Read boot sector and volume info from a FAT filesystem
745   */
746  static int
747  read_bootsectandvi(boot_sector *bs, volume_info *volinfo, int *fatsize)
748  {
749  	__u8 *block;
750  	volume_info *vistart;
751  	int ret = 0;
752  
753  	if (cur_dev == NULL) {
754  		debug("Error: no device selected\n");
755  		return -1;
756  	}
757  
758  	block = memalign(ARCH_DMA_MINALIGN, cur_dev->blksz);
759  	if (block == NULL) {
760  		debug("Error: allocating block\n");
761  		return -1;
762  	}
763  
764  	if (disk_read(0, 1, block) < 0) {
765  		debug("Error: reading block\n");
766  		goto fail;
767  	}
768  
769  	memcpy(bs, block, sizeof(boot_sector));
770  	bs->reserved = FAT2CPU16(bs->reserved);
771  	bs->fat_length = FAT2CPU16(bs->fat_length);
772  	bs->secs_track = FAT2CPU16(bs->secs_track);
773  	bs->heads = FAT2CPU16(bs->heads);
774  	bs->total_sect = FAT2CPU32(bs->total_sect);
775  
776  	/* FAT32 entries */
777  	if (bs->fat_length == 0) {
778  		/* Assume FAT32 */
779  		bs->fat32_length = FAT2CPU32(bs->fat32_length);
780  		bs->flags = FAT2CPU16(bs->flags);
781  		bs->root_cluster = FAT2CPU32(bs->root_cluster);
782  		bs->info_sector = FAT2CPU16(bs->info_sector);
783  		bs->backup_boot = FAT2CPU16(bs->backup_boot);
784  		vistart = (volume_info *)(block + sizeof(boot_sector));
785  		*fatsize = 32;
786  	} else {
787  		vistart = (volume_info *)&(bs->fat32_length);
788  		*fatsize = 0;
789  	}
790  	memcpy(volinfo, vistart, sizeof(volume_info));
791  
792  	if (*fatsize == 32) {
793  		if (strncmp(FAT32_SIGN, vistart->fs_type, SIGNLEN) == 0)
794  			goto exit;
795  	} else {
796  		if (strncmp(FAT12_SIGN, vistart->fs_type, SIGNLEN) == 0) {
797  			*fatsize = 12;
798  			goto exit;
799  		}
800  		if (strncmp(FAT16_SIGN, vistart->fs_type, SIGNLEN) == 0) {
801  			*fatsize = 16;
802  			goto exit;
803  		}
804  	}
805  
806  	debug("Error: broken fs_type sign\n");
807  fail:
808  	ret = -1;
809  exit:
810  	free(block);
811  	return ret;
812  }
813  
814  __u8 do_fat_read_at_block[MAX_CLUSTSIZE]
815  	__aligned(ARCH_DMA_MINALIGN);
816  
817  int do_fat_read_at(const char *filename, loff_t pos, void *buffer,
818  		   loff_t maxsize, int dols, int dogetsize, loff_t *size)
819  {
820  	char fnamecopy[2048];
821  	boot_sector bs;
822  	volume_info volinfo;
823  	fsdata datablock;
824  	fsdata *mydata = &datablock;
825  	dir_entry *dentptr = NULL;
826  	__u16 prevcksum = 0xffff;
827  	char *subname = "";
828  	__u32 cursect;
829  	int idx, isdir = 0;
830  	int files = 0, dirs = 0;
831  	int ret = -1;
832  	int firsttime;
833  	__u32 root_cluster = 0;
834  	__u32 read_blk;
835  	int rootdir_size = 0;
836  	int buffer_blk_cnt;
837  	int do_read;
838  	__u8 *dir_ptr;
839  
840  	if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
841  		debug("Error: reading boot sector\n");
842  		return -1;
843  	}
844  
845  	if (mydata->fatsize == 32) {
846  		root_cluster = bs.root_cluster;
847  		mydata->fatlength = bs.fat32_length;
848  	} else {
849  		mydata->fatlength = bs.fat_length;
850  	}
851  
852  	mydata->fat_sect = bs.reserved;
853  
854  	cursect = mydata->rootdir_sect
855  		= mydata->fat_sect + mydata->fatlength * bs.fats;
856  
857  	mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
858  	mydata->clust_size = bs.cluster_size;
859  	if (mydata->sect_size != cur_part_info.blksz) {
860  		printf("Error: FAT sector size mismatch (fs=%hu, dev=%lu)\n",
861  				mydata->sect_size, cur_part_info.blksz);
862  		return -1;
863  	}
864  
865  	if (mydata->fatsize == 32) {
866  		mydata->data_begin = mydata->rootdir_sect -
867  					(mydata->clust_size * 2);
868  	} else {
869  		rootdir_size = ((bs.dir_entries[1]  * (int)256 +
870  				 bs.dir_entries[0]) *
871  				 sizeof(dir_entry)) /
872  				 mydata->sect_size;
873  		mydata->data_begin = mydata->rootdir_sect +
874  					rootdir_size -
875  					(mydata->clust_size * 2);
876  	}
877  
878  	mydata->fatbufnum = -1;
879  	mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
880  	if (mydata->fatbuf == NULL) {
881  		debug("Error: allocating memory\n");
882  		return -1;
883  	}
884  
885  	if (vfat_enabled)
886  		debug("VFAT Support enabled\n");
887  
888  	debug("FAT%d, fat_sect: %d, fatlength: %d\n",
889  	       mydata->fatsize, mydata->fat_sect, mydata->fatlength);
890  	debug("Rootdir begins at cluster: %d, sector: %d, offset: %x\n"
891  	       "Data begins at: %d\n",
892  	       root_cluster,
893  	       mydata->rootdir_sect,
894  	       mydata->rootdir_sect * mydata->sect_size, mydata->data_begin);
895  	debug("Sector size: %d, cluster size: %d\n", mydata->sect_size,
896  	      mydata->clust_size);
897  
898  	/* "cwd" is always the root... */
899  	while (ISDIRDELIM(*filename))
900  		filename++;
901  
902  	/* Make a copy of the filename and convert it to lowercase */
903  	strcpy(fnamecopy, filename);
904  	downcase(fnamecopy);
905  
906  root_reparse:
907  	if (*fnamecopy == '\0') {
908  		if (!dols)
909  			goto exit;
910  
911  		dols = LS_ROOT;
912  	} else if ((idx = dirdelim(fnamecopy)) >= 0) {
913  		isdir = 1;
914  		fnamecopy[idx] = '\0';
915  		subname = fnamecopy + idx + 1;
916  
917  		/* Handle multiple delimiters */
918  		while (ISDIRDELIM(*subname))
919  			subname++;
920  	} else if (dols) {
921  		isdir = 1;
922  	}
923  
924  	buffer_blk_cnt = 0;
925  	firsttime = 1;
926  	while (1) {
927  		int i;
928  
929  		if (mydata->fatsize == 32 || firsttime) {
930  			dir_ptr = do_fat_read_at_block;
931  			firsttime = 0;
932  		} else {
933  			/**
934  			 * FAT16 sector buffer modification:
935  			 * Each loop, the second buffered block is moved to
936  			 * the buffer begin, and two next sectors are read
937  			 * next to the previously moved one. So the sector
938  			 * buffer keeps always 3 sectors for fat16.
939  			 * And the current sector is the buffer second sector
940  			 * beside the "firsttime" read, when it is the first one.
941  			 *
942  			 * PREFETCH_BLOCKS is 2 for FAT16 == loop[0:1]
943  			 * n = computed root dir sector
944  			 * loop |  cursect-1  | cursect    | cursect+1  |
945  			 *   0  |  sector n+0 | sector n+1 | none       |
946  			 *   1  |  none       | sector n+0 | sector n+1 |
947  			 *   0  |  sector n+1 | sector n+2 | sector n+3 |
948  			 *   1  |  sector n+3 | ...
949  			*/
950  			dir_ptr = (do_fat_read_at_block + mydata->sect_size);
951  			memcpy(do_fat_read_at_block, dir_ptr, mydata->sect_size);
952  		}
953  
954  		do_read = 1;
955  
956  		if (mydata->fatsize == 32 && buffer_blk_cnt)
957  			do_read = 0;
958  
959  		if (do_read) {
960  			read_blk = (mydata->fatsize == 32) ?
961  				    mydata->clust_size : PREFETCH_BLOCKS;
962  
963  			debug("FAT read(sect=%d, cnt:%d), clust_size=%d, DIRENTSPERBLOCK=%zd\n",
964  				cursect, read_blk, mydata->clust_size, DIRENTSPERBLOCK);
965  
966  			if (disk_read(cursect, read_blk, dir_ptr) < 0) {
967  				debug("Error: reading rootdir block\n");
968  				goto exit;
969  			}
970  
971  			dentptr = (dir_entry *)dir_ptr;
972  		}
973  
974  		for (i = 0; i < DIRENTSPERBLOCK; i++) {
975  			char s_name[14], l_name[VFAT_MAXLEN_BYTES];
976  			__u8 csum;
977  
978  			l_name[0] = '\0';
979  			if (dentptr->name[0] == DELETED_FLAG) {
980  				dentptr++;
981  				continue;
982  			}
983  
984  			if (vfat_enabled)
985  				csum = mkcksum(dentptr->name, dentptr->ext);
986  
987  			if (dentptr->attr & ATTR_VOLUME) {
988  				if (vfat_enabled &&
989  				    (dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
990  				    (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
991  					prevcksum =
992  						((dir_slot *)dentptr)->alias_checksum;
993  
994  					get_vfatname(mydata,
995  						     root_cluster,
996  						     dir_ptr,
997  						     dentptr, l_name);
998  
999  					if (dols == LS_ROOT) {
1000  						char dirc;
1001  						int doit = 0;
1002  						int isdir =
1003  							(dentptr->attr & ATTR_DIR);
1004  
1005  						if (isdir) {
1006  							dirs++;
1007  							dirc = '/';
1008  							doit = 1;
1009  						} else {
1010  							dirc = ' ';
1011  							if (l_name[0] != 0) {
1012  								files++;
1013  								doit = 1;
1014  							}
1015  						}
1016  						if (doit) {
1017  							if (dirc == ' ') {
1018  								printf(" %8u   %s%c\n",
1019  								       FAT2CPU32(dentptr->size),
1020  									l_name,
1021  									dirc);
1022  							} else {
1023  								printf("            %s%c\n",
1024  									l_name,
1025  									dirc);
1026  							}
1027  						}
1028  						dentptr++;
1029  						continue;
1030  					}
1031  					debug("Rootvfatname: |%s|\n",
1032  					       l_name);
1033  				} else {
1034  					/* Volume label or VFAT entry */
1035  					dentptr++;
1036  					continue;
1037  				}
1038  			} else if (dentptr->name[0] == 0) {
1039  				debug("RootDentname == NULL - %d\n", i);
1040  				if (dols == LS_ROOT) {
1041  					printf("\n%d file(s), %d dir(s)\n\n",
1042  						files, dirs);
1043  					ret = 0;
1044  				}
1045  				goto exit;
1046  			}
1047  			else if (vfat_enabled &&
1048  				 dols == LS_ROOT && csum == prevcksum) {
1049  				prevcksum = 0xffff;
1050  				dentptr++;
1051  				continue;
1052  			}
1053  
1054  			get_name(dentptr, s_name);
1055  
1056  			if (dols == LS_ROOT) {
1057  				int isdir = (dentptr->attr & ATTR_DIR);
1058  				char dirc;
1059  				int doit = 0;
1060  
1061  				if (isdir) {
1062  					dirc = '/';
1063  					if (s_name[0] != 0) {
1064  						dirs++;
1065  						doit = 1;
1066  					}
1067  				} else {
1068  					dirc = ' ';
1069  					if (s_name[0] != 0) {
1070  						files++;
1071  						doit = 1;
1072  					}
1073  				}
1074  				if (doit) {
1075  					if (dirc == ' ') {
1076  						printf(" %8u   %s%c\n",
1077  						       FAT2CPU32(dentptr->size),
1078  							s_name, dirc);
1079  					} else {
1080  						printf("            %s%c\n",
1081  							s_name, dirc);
1082  					}
1083  				}
1084  				dentptr++;
1085  				continue;
1086  			}
1087  
1088  			if (strcmp(fnamecopy, s_name)
1089  			    && strcmp(fnamecopy, l_name)) {
1090  				debug("RootMismatch: |%s|%s|\n", s_name,
1091  				       l_name);
1092  				dentptr++;
1093  				continue;
1094  			}
1095  
1096  			if (isdir && !(dentptr->attr & ATTR_DIR))
1097  				goto exit;
1098  
1099  			debug("RootName: %s", s_name);
1100  			debug(", start: 0x%x", START(dentptr));
1101  			debug(", size:  0x%x %s\n",
1102  			       FAT2CPU32(dentptr->size),
1103  			       isdir ? "(DIR)" : "");
1104  
1105  			goto rootdir_done;	/* We got a match */
1106  		}
1107  		debug("END LOOP: buffer_blk_cnt=%d   clust_size=%d\n", buffer_blk_cnt,
1108  		       mydata->clust_size);
1109  
1110  		/*
1111  		 * On FAT32 we must fetch the FAT entries for the next
1112  		 * root directory clusters when a cluster has been
1113  		 * completely processed.
1114  		 */
1115  		++buffer_blk_cnt;
1116  		int rootdir_end = 0;
1117  		if (mydata->fatsize == 32) {
1118  			if (buffer_blk_cnt == mydata->clust_size) {
1119  				int nxtsect = 0;
1120  				int nxt_clust = 0;
1121  
1122  				nxt_clust = get_fatent(mydata, root_cluster);
1123  				rootdir_end = CHECK_CLUST(nxt_clust, 32);
1124  
1125  				nxtsect = mydata->data_begin +
1126  					(nxt_clust * mydata->clust_size);
1127  
1128  				root_cluster = nxt_clust;
1129  
1130  				cursect = nxtsect;
1131  				buffer_blk_cnt = 0;
1132  			}
1133  		} else {
1134  			if (buffer_blk_cnt == PREFETCH_BLOCKS)
1135  				buffer_blk_cnt = 0;
1136  
1137  			rootdir_end = (++cursect - mydata->rootdir_sect >=
1138  				       rootdir_size);
1139  		}
1140  
1141  		/* If end of rootdir reached */
1142  		if (rootdir_end) {
1143  			if (dols == LS_ROOT) {
1144  				printf("\n%d file(s), %d dir(s)\n\n",
1145  				       files, dirs);
1146  				*size = 0;
1147  			}
1148  			goto exit;
1149  		}
1150  	}
1151  rootdir_done:
1152  
1153  	firsttime = 1;
1154  
1155  	while (isdir) {
1156  		int startsect = mydata->data_begin
1157  			+ START(dentptr) * mydata->clust_size;
1158  		dir_entry dent;
1159  		char *nextname = NULL;
1160  
1161  		dent = *dentptr;
1162  		dentptr = &dent;
1163  
1164  		idx = dirdelim(subname);
1165  
1166  		if (idx >= 0) {
1167  			subname[idx] = '\0';
1168  			nextname = subname + idx + 1;
1169  			/* Handle multiple delimiters */
1170  			while (ISDIRDELIM(*nextname))
1171  				nextname++;
1172  			if (dols && *nextname == '\0')
1173  				firsttime = 0;
1174  		} else {
1175  			if (dols && firsttime) {
1176  				firsttime = 0;
1177  			} else {
1178  				isdir = 0;
1179  			}
1180  		}
1181  
1182  		if (get_dentfromdir(mydata, startsect, subname, dentptr,
1183  				     isdir ? 0 : dols) == NULL) {
1184  			if (dols && !isdir)
1185  				*size = 0;
1186  			goto exit;
1187  		}
1188  
1189  		if (isdir && !(dentptr->attr & ATTR_DIR))
1190  			goto exit;
1191  
1192  		/*
1193  		 * If we are looking for a directory, and found a directory
1194  		 * type entry, and the entry is for the root directory (as
1195  		 * denoted by a cluster number of 0), jump back to the start
1196  		 * of the function, since at least on FAT12/16, the root dir
1197  		 * lives in a hard-coded location and needs special handling
1198  		 * to parse, rather than simply following the cluster linked
1199  		 * list in the FAT, like other directories.
1200  		 */
1201  		if (isdir && (dentptr->attr & ATTR_DIR) && !START(dentptr)) {
1202  			/*
1203  			 * Modify the filename to remove the prefix that gets
1204  			 * back to the root directory, so the initial root dir
1205  			 * parsing code can continue from where we are without
1206  			 * confusion.
1207  			 */
1208  			strcpy(fnamecopy, nextname ?: "");
1209  			/*
1210  			 * Set up state the same way as the function does when
1211  			 * first started. This is required for the root dir
1212  			 * parsing code operates in its expected environment.
1213  			 */
1214  			subname = "";
1215  			cursect = mydata->rootdir_sect;
1216  			isdir = 0;
1217  			goto root_reparse;
1218  		}
1219  
1220  		if (idx >= 0)
1221  			subname = nextname;
1222  	}
1223  
1224  	if (dogetsize) {
1225  		*size = FAT2CPU32(dentptr->size);
1226  		ret = 0;
1227  	} else {
1228  		ret = get_contents(mydata, dentptr, pos, buffer, maxsize, size);
1229  	}
1230  	debug("Size: %u, got: %llu\n", FAT2CPU32(dentptr->size), *size);
1231  
1232  exit:
1233  	free(mydata->fatbuf);
1234  	return ret;
1235  }
1236  
1237  int do_fat_read(const char *filename, void *buffer, loff_t maxsize, int dols,
1238  		loff_t *actread)
1239  {
1240  	return do_fat_read_at(filename, 0, buffer, maxsize, dols, 0, actread);
1241  }
1242  
1243  int file_fat_detectfs(void)
1244  {
1245  	boot_sector bs;
1246  	volume_info volinfo;
1247  	int fatsize;
1248  	char vol_label[12];
1249  
1250  	if (cur_dev == NULL) {
1251  		printf("No current device\n");
1252  		return 1;
1253  	}
1254  
1255  #if defined(CONFIG_CMD_IDE) || \
1256      defined(CONFIG_CMD_SATA) || \
1257      defined(CONFIG_CMD_SCSI) || \
1258      defined(CONFIG_CMD_USB) || \
1259      defined(CONFIG_MMC)
1260  	printf("Interface:  ");
1261  	switch (cur_dev->if_type) {
1262  	case IF_TYPE_IDE:
1263  		printf("IDE");
1264  		break;
1265  	case IF_TYPE_SATA:
1266  		printf("SATA");
1267  		break;
1268  	case IF_TYPE_SCSI:
1269  		printf("SCSI");
1270  		break;
1271  	case IF_TYPE_ATAPI:
1272  		printf("ATAPI");
1273  		break;
1274  	case IF_TYPE_USB:
1275  		printf("USB");
1276  		break;
1277  	case IF_TYPE_DOC:
1278  		printf("DOC");
1279  		break;
1280  	case IF_TYPE_MMC:
1281  		printf("MMC");
1282  		break;
1283  	default:
1284  		printf("Unknown");
1285  	}
1286  
1287  	printf("\n  Device %d: ", cur_dev->dev);
1288  	dev_print(cur_dev);
1289  #endif
1290  
1291  	if (read_bootsectandvi(&bs, &volinfo, &fatsize)) {
1292  		printf("\nNo valid FAT fs found\n");
1293  		return 1;
1294  	}
1295  
1296  	memcpy(vol_label, volinfo.volume_label, 11);
1297  	vol_label[11] = '\0';
1298  	volinfo.fs_type[5] = '\0';
1299  
1300  	printf("Filesystem: %s \"%s\"\n", volinfo.fs_type, vol_label);
1301  
1302  	return 0;
1303  }
1304  
1305  int file_fat_ls(const char *dir)
1306  {
1307  	loff_t size;
1308  
1309  	return do_fat_read(dir, NULL, 0, LS_YES, &size);
1310  }
1311  
1312  int fat_exists(const char *filename)
1313  {
1314  	int ret;
1315  	loff_t size;
1316  
1317  	ret = do_fat_read_at(filename, 0, NULL, 0, LS_NO, 1, &size);
1318  	return ret == 0;
1319  }
1320  
1321  int fat_size(const char *filename, loff_t *size)
1322  {
1323  	return do_fat_read_at(filename, 0, NULL, 0, LS_NO, 1, size);
1324  }
1325  
1326  int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
1327  		     loff_t maxsize, loff_t *actread)
1328  {
1329  	printf("reading %s\n", filename);
1330  	return do_fat_read_at(filename, pos, buffer, maxsize, LS_NO, 0,
1331  			      actread);
1332  }
1333  
1334  int file_fat_read(const char *filename, void *buffer, int maxsize)
1335  {
1336  	loff_t actread;
1337  	int ret;
1338  
1339  	ret =  file_fat_read_at(filename, 0, buffer, maxsize, &actread);
1340  	if (ret)
1341  		return ret;
1342  	else
1343  		return actread;
1344  }
1345  
1346  int fat_read_file(const char *filename, void *buf, loff_t offset, loff_t len,
1347  		  loff_t *actread)
1348  {
1349  	int ret;
1350  
1351  	ret = file_fat_read_at(filename, offset, buf, len, actread);
1352  	if (ret)
1353  		printf("** Unable to read file %s **\n", filename);
1354  
1355  	return ret;
1356  }
1357  
1358  void fat_close(void)
1359  {
1360  }
1361