Merge tag 'fixes-for-v2020.04' of https://gitlab.denx.de/u-boot/custodians/u-boot...
[platform/kernel/u-boot.git] / fs / fat / fat_write.c
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * fat_write.c
4  *
5  * R/W (V)FAT 12/16/32 filesystem implementation by Donggeun Kim
6  */
7
8 #include <common.h>
9 #include <command.h>
10 #include <config.h>
11 #include <fat.h>
12 #include <asm/byteorder.h>
13 #include <part.h>
14 #include <linux/ctype.h>
15 #include <div64.h>
16 #include <linux/math64.h>
17 #include "fat.c"
18
19 static void uppercase(char *str, int len)
20 {
21         int i;
22
23         for (i = 0; i < len; i++) {
24                 *str = toupper(*str);
25                 str++;
26         }
27 }
28
29 static int total_sector;
30 static int disk_write(__u32 block, __u32 nr_blocks, void *buf)
31 {
32         ulong ret;
33
34         if (!cur_dev)
35                 return -1;
36
37         if (cur_part_info.start + block + nr_blocks >
38                 cur_part_info.start + total_sector) {
39                 printf("error: overflow occurs\n");
40                 return -1;
41         }
42
43         ret = blk_dwrite(cur_dev, cur_part_info.start + block, nr_blocks, buf);
44         if (nr_blocks && ret == 0)
45                 return -1;
46
47         return ret;
48 }
49
50 /*
51  * Set short name in directory entry
52  */
53 static void set_name(dir_entry *dirent, const char *filename)
54 {
55         char s_name[VFAT_MAXLEN_BYTES];
56         char *period;
57         int period_location, len, i, ext_num;
58
59         if (filename == NULL)
60                 return;
61
62         len = strlen(filename);
63         if (len == 0)
64                 return;
65
66         strcpy(s_name, filename);
67         uppercase(s_name, len);
68
69         period = strchr(s_name, '.');
70         if (period == NULL) {
71                 period_location = len;
72                 ext_num = 0;
73         } else {
74                 period_location = period - s_name;
75                 ext_num = len - period_location - 1;
76         }
77
78         /* Pad spaces when the length of file name is shorter than eight */
79         if (period_location < 8) {
80                 memcpy(dirent->name, s_name, period_location);
81                 for (i = period_location; i < 8; i++)
82                         dirent->name[i] = ' ';
83         } else if (period_location == 8) {
84                 memcpy(dirent->name, s_name, period_location);
85         } else {
86                 memcpy(dirent->name, s_name, 6);
87                 dirent->name[6] = '~';
88                 dirent->name[7] = '1';
89         }
90
91         if (ext_num < 3) {
92                 memcpy(dirent->ext, s_name + period_location + 1, ext_num);
93                 for (i = ext_num; i < 3; i++)
94                         dirent->ext[i] = ' ';
95         } else
96                 memcpy(dirent->ext, s_name + period_location + 1, 3);
97
98         debug("name : %s\n", dirent->name);
99         debug("ext : %s\n", dirent->ext);
100 }
101
102 /*
103  * Write fat buffer into block device
104  */
105 static int flush_dirty_fat_buffer(fsdata *mydata)
106 {
107         int getsize = FATBUFBLOCKS;
108         __u32 fatlength = mydata->fatlength;
109         __u8 *bufptr = mydata->fatbuf;
110         __u32 startblock = mydata->fatbufnum * FATBUFBLOCKS;
111
112         debug("debug: evicting %d, dirty: %d\n", mydata->fatbufnum,
113               (int)mydata->fat_dirty);
114
115         if ((!mydata->fat_dirty) || (mydata->fatbufnum == -1))
116                 return 0;
117
118         /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
119         if (startblock + getsize > fatlength)
120                 getsize = fatlength - startblock;
121
122         startblock += mydata->fat_sect;
123
124         /* Write FAT buf */
125         if (disk_write(startblock, getsize, bufptr) < 0) {
126                 debug("error: writing FAT blocks\n");
127                 return -1;
128         }
129
130         if (mydata->fats == 2) {
131                 /* Update corresponding second FAT blocks */
132                 startblock += mydata->fatlength;
133                 if (disk_write(startblock, getsize, bufptr) < 0) {
134                         debug("error: writing second FAT blocks\n");
135                         return -1;
136                 }
137         }
138         mydata->fat_dirty = 0;
139
140         return 0;
141 }
142
143 /*
144  * Set the file name information from 'name' into 'slotptr',
145  */
146 static int str2slot(dir_slot *slotptr, const char *name, int *idx)
147 {
148         int j, end_idx = 0;
149
150         for (j = 0; j <= 8; j += 2) {
151                 if (name[*idx] == 0x00) {
152                         slotptr->name0_4[j] = 0;
153                         slotptr->name0_4[j + 1] = 0;
154                         end_idx++;
155                         goto name0_4;
156                 }
157                 slotptr->name0_4[j] = name[*idx];
158                 (*idx)++;
159                 end_idx++;
160         }
161         for (j = 0; j <= 10; j += 2) {
162                 if (name[*idx] == 0x00) {
163                         slotptr->name5_10[j] = 0;
164                         slotptr->name5_10[j + 1] = 0;
165                         end_idx++;
166                         goto name5_10;
167                 }
168                 slotptr->name5_10[j] = name[*idx];
169                 (*idx)++;
170                 end_idx++;
171         }
172         for (j = 0; j <= 2; j += 2) {
173                 if (name[*idx] == 0x00) {
174                         slotptr->name11_12[j] = 0;
175                         slotptr->name11_12[j + 1] = 0;
176                         end_idx++;
177                         goto name11_12;
178                 }
179                 slotptr->name11_12[j] = name[*idx];
180                 (*idx)++;
181                 end_idx++;
182         }
183
184         if (name[*idx] == 0x00)
185                 return 1;
186
187         return 0;
188 /* Not used characters are filled with 0xff 0xff */
189 name0_4:
190         for (; end_idx < 5; end_idx++) {
191                 slotptr->name0_4[end_idx * 2] = 0xff;
192                 slotptr->name0_4[end_idx * 2 + 1] = 0xff;
193         }
194         end_idx = 5;
195 name5_10:
196         end_idx -= 5;
197         for (; end_idx < 6; end_idx++) {
198                 slotptr->name5_10[end_idx * 2] = 0xff;
199                 slotptr->name5_10[end_idx * 2 + 1] = 0xff;
200         }
201         end_idx = 11;
202 name11_12:
203         end_idx -= 11;
204         for (; end_idx < 2; end_idx++) {
205                 slotptr->name11_12[end_idx * 2] = 0xff;
206                 slotptr->name11_12[end_idx * 2 + 1] = 0xff;
207         }
208
209         return 1;
210 }
211
212 static int new_dir_table(fat_itr *itr);
213 static int flush_dir(fat_itr *itr);
214
215 /*
216  * Fill dir_slot entries with appropriate name, id, and attr
217  * 'itr' will point to a next entry
218  */
219 static int
220 fill_dir_slot(fat_itr *itr, const char *l_name)
221 {
222         __u8 temp_dir_slot_buffer[MAX_LFN_SLOT * sizeof(dir_slot)];
223         dir_slot *slotptr = (dir_slot *)temp_dir_slot_buffer;
224         __u8 counter = 0, checksum;
225         int idx = 0, ret;
226
227         /* Get short file name checksum value */
228         checksum = mkcksum(itr->dent->name, itr->dent->ext);
229
230         do {
231                 memset(slotptr, 0x00, sizeof(dir_slot));
232                 ret = str2slot(slotptr, l_name, &idx);
233                 slotptr->id = ++counter;
234                 slotptr->attr = ATTR_VFAT;
235                 slotptr->alias_checksum = checksum;
236                 slotptr++;
237         } while (ret == 0);
238
239         slotptr--;
240         slotptr->id |= LAST_LONG_ENTRY_MASK;
241
242         while (counter >= 1) {
243                 memcpy(itr->dent, slotptr, sizeof(dir_slot));
244                 slotptr--;
245                 counter--;
246
247                 if (itr->remaining == 0)
248                         flush_dir(itr);
249
250                 /* allocate a cluster for more entries */
251                 if (!fat_itr_next(itr))
252                         if (!itr->dent &&
253                             (!itr->is_root || itr->fsdata->fatsize == 32) &&
254                             new_dir_table(itr))
255                                 return -1;
256         }
257
258         return 0;
259 }
260
261 /*
262  * Set the entry at index 'entry' in a FAT (12/16/32) table.
263  */
264 static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
265 {
266         __u32 bufnum, offset, off16;
267         __u16 val1, val2;
268
269         switch (mydata->fatsize) {
270         case 32:
271                 bufnum = entry / FAT32BUFSIZE;
272                 offset = entry - bufnum * FAT32BUFSIZE;
273                 break;
274         case 16:
275                 bufnum = entry / FAT16BUFSIZE;
276                 offset = entry - bufnum * FAT16BUFSIZE;
277                 break;
278         case 12:
279                 bufnum = entry / FAT12BUFSIZE;
280                 offset = entry - bufnum * FAT12BUFSIZE;
281                 break;
282         default:
283                 /* Unsupported FAT size */
284                 return -1;
285         }
286
287         /* Read a new block of FAT entries into the cache. */
288         if (bufnum != mydata->fatbufnum) {
289                 int getsize = FATBUFBLOCKS;
290                 __u8 *bufptr = mydata->fatbuf;
291                 __u32 fatlength = mydata->fatlength;
292                 __u32 startblock = bufnum * FATBUFBLOCKS;
293
294                 /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
295                 if (startblock + getsize > fatlength)
296                         getsize = fatlength - startblock;
297
298                 if (flush_dirty_fat_buffer(mydata) < 0)
299                         return -1;
300
301                 startblock += mydata->fat_sect;
302
303                 if (disk_read(startblock, getsize, bufptr) < 0) {
304                         debug("Error reading FAT blocks\n");
305                         return -1;
306                 }
307                 mydata->fatbufnum = bufnum;
308         }
309
310         /* Mark as dirty */
311         mydata->fat_dirty = 1;
312
313         /* Set the actual entry */
314         switch (mydata->fatsize) {
315         case 32:
316                 ((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
317                 break;
318         case 16:
319                 ((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
320                 break;
321         case 12:
322                 off16 = (offset * 3) / 4;
323
324                 switch (offset & 0x3) {
325                 case 0:
326                         val1 = cpu_to_le16(entry_value) & 0xfff;
327                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff;
328                         ((__u16 *)mydata->fatbuf)[off16] |= val1;
329                         break;
330                 case 1:
331                         val1 = cpu_to_le16(entry_value) & 0xf;
332                         val2 = (cpu_to_le16(entry_value) >> 4) & 0xff;
333
334                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xf000;
335                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 12);
336
337                         ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xff;
338                         ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
339                         break;
340                 case 2:
341                         val1 = cpu_to_le16(entry_value) & 0xff;
342                         val2 = (cpu_to_le16(entry_value) >> 8) & 0xf;
343
344                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xff00;
345                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 8);
346
347                         ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xf;
348                         ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
349                         break;
350                 case 3:
351                         val1 = cpu_to_le16(entry_value) & 0xfff;
352                         ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff0;
353                         ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 4);
354                         break;
355                 default:
356                         break;
357                 }
358
359                 break;
360         default:
361                 return -1;
362         }
363
364         return 0;
365 }
366
367 /*
368  * Determine the next free cluster after 'entry' in a FAT (12/16/32) table
369  * and link it to 'entry'. EOC marker is not set on returned entry.
370  */
371 static __u32 determine_fatent(fsdata *mydata, __u32 entry)
372 {
373         __u32 next_fat, next_entry = entry + 1;
374
375         while (1) {
376                 next_fat = get_fatent(mydata, next_entry);
377                 if (next_fat == 0) {
378                         /* found free entry, link to entry */
379                         set_fatent_value(mydata, entry, next_entry);
380                         break;
381                 }
382                 next_entry++;
383         }
384         debug("FAT%d: entry: %08x, entry_value: %04x\n",
385                mydata->fatsize, entry, next_entry);
386
387         return next_entry;
388 }
389
390 /**
391  * set_sectors() - write data to sectors
392  *
393  * Write 'size' bytes from 'buffer' into the specified sector.
394  *
395  * @mydata:     data to be written
396  * @startsect:  sector to be written to
397  * @buffer:     data to be written
398  * @size:       bytes to be written (but not more than the size of a cluster)
399  * Return:      0 on success, -1 otherwise
400  */
401 static int
402 set_sectors(fsdata *mydata, u32 startsect, u8 *buffer, u32 size)
403 {
404         u32 nsects = 0;
405         int ret;
406
407         debug("startsect: %d\n", startsect);
408
409         if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
410                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
411
412                 debug("FAT: Misaligned buffer address (%p)\n", buffer);
413
414                 while (size >= mydata->sect_size) {
415                         memcpy(tmpbuf, buffer, mydata->sect_size);
416                         ret = disk_write(startsect++, 1, tmpbuf);
417                         if (ret != 1) {
418                                 debug("Error writing data (got %d)\n", ret);
419                                 return -1;
420                         }
421
422                         buffer += mydata->sect_size;
423                         size -= mydata->sect_size;
424                 }
425         } else if (size >= mydata->sect_size) {
426                 nsects = size / mydata->sect_size;
427                 ret = disk_write(startsect, nsects, buffer);
428                 if (ret != nsects) {
429                         debug("Error writing data (got %d)\n", ret);
430                         return -1;
431                 }
432
433                 startsect += nsects;
434                 buffer += nsects * mydata->sect_size;
435                 size -= nsects * mydata->sect_size;
436         }
437
438         if (size) {
439                 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
440                 /* Do not leak content of stack */
441                 memset(tmpbuf, 0, mydata->sect_size);
442                 memcpy(tmpbuf, buffer, size);
443                 ret = disk_write(startsect, 1, tmpbuf);
444                 if (ret != 1) {
445                         debug("Error writing data (got %d)\n", ret);
446                         return -1;
447                 }
448         }
449
450         return 0;
451 }
452
453 /**
454  * set_cluster() - write data to cluster
455  *
456  * Write 'size' bytes from 'buffer' into the specified cluster.
457  *
458  * @mydata:     data to be written
459  * @clustnum:   cluster to be written to
460  * @buffer:     data to be written
461  * @size:       bytes to be written (but not more than the size of a cluster)
462  * Return:      0 on success, -1 otherwise
463  */
464 static int
465 set_cluster(fsdata *mydata, u32 clustnum, u8 *buffer, u32 size)
466 {
467         return set_sectors(mydata, clust_to_sect(mydata, clustnum),
468                            buffer, size);
469 }
470
471 static int
472 flush_dir(fat_itr *itr)
473 {
474         fsdata *mydata = itr->fsdata;
475         u32 startsect, sect_offset, nsects;
476
477         if (!itr->is_root || mydata->fatsize == 32)
478                 return set_cluster(mydata, itr->clust, itr->block,
479                                    mydata->clust_size * mydata->sect_size);
480
481         sect_offset = itr->clust * mydata->clust_size;
482         startsect = mydata->rootdir_sect + sect_offset;
483         /* do not write past the end of rootdir */
484         nsects = min_t(u32, mydata->clust_size,
485                        mydata->rootdir_size - sect_offset);
486
487         return set_sectors(mydata, startsect, itr->block,
488                            nsects * mydata->sect_size);
489 }
490
491 static __u8 tmpbuf_cluster[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
492
493 /*
494  * Read and modify data on existing and consecutive cluster blocks
495  */
496 static int
497 get_set_cluster(fsdata *mydata, __u32 clustnum, loff_t pos, __u8 *buffer,
498                 loff_t size, loff_t *gotsize)
499 {
500         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
501         __u32 startsect;
502         loff_t wsize;
503         int clustcount, i, ret;
504
505         *gotsize = 0;
506         if (!size)
507                 return 0;
508
509         assert(pos < bytesperclust);
510         startsect = clust_to_sect(mydata, clustnum);
511
512         debug("clustnum: %d, startsect: %d, pos: %lld\n",
513               clustnum, startsect, pos);
514
515         /* partial write at beginning */
516         if (pos) {
517                 wsize = min(bytesperclust - pos, size);
518                 ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
519                 if (ret != mydata->clust_size) {
520                         debug("Error reading data (got %d)\n", ret);
521                         return -1;
522                 }
523
524                 memcpy(tmpbuf_cluster + pos, buffer, wsize);
525                 ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
526                 if (ret != mydata->clust_size) {
527                         debug("Error writing data (got %d)\n", ret);
528                         return -1;
529                 }
530
531                 size -= wsize;
532                 buffer += wsize;
533                 *gotsize += wsize;
534
535                 startsect += mydata->clust_size;
536
537                 if (!size)
538                         return 0;
539         }
540
541         /* full-cluster write */
542         if (size >= bytesperclust) {
543                 clustcount = lldiv(size, bytesperclust);
544
545                 if (!((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1))) {
546                         wsize = clustcount * bytesperclust;
547                         ret = disk_write(startsect,
548                                          clustcount * mydata->clust_size,
549                                          buffer);
550                         if (ret != clustcount * mydata->clust_size) {
551                                 debug("Error writing data (got %d)\n", ret);
552                                 return -1;
553                         }
554
555                         size -= wsize;
556                         buffer += wsize;
557                         *gotsize += wsize;
558
559                         startsect += clustcount * mydata->clust_size;
560                 } else {
561                         for (i = 0; i < clustcount; i++) {
562                                 memcpy(tmpbuf_cluster, buffer, bytesperclust);
563                                 ret = disk_write(startsect,
564                                                  mydata->clust_size,
565                                                  tmpbuf_cluster);
566                                 if (ret != mydata->clust_size) {
567                                         debug("Error writing data (got %d)\n",
568                                               ret);
569                                         return -1;
570                                 }
571
572                                 size -= bytesperclust;
573                                 buffer += bytesperclust;
574                                 *gotsize += bytesperclust;
575
576                                 startsect += mydata->clust_size;
577                         }
578                 }
579         }
580
581         /* partial write at end */
582         if (size) {
583                 wsize = size;
584                 ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
585                 if (ret != mydata->clust_size) {
586                         debug("Error reading data (got %d)\n", ret);
587                         return -1;
588                 }
589                 memcpy(tmpbuf_cluster, buffer, wsize);
590                 ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
591                 if (ret != mydata->clust_size) {
592                         debug("Error writing data (got %d)\n", ret);
593                         return -1;
594                 }
595
596                 size -= wsize;
597                 buffer += wsize;
598                 *gotsize += wsize;
599         }
600
601         assert(!size);
602
603         return 0;
604 }
605
606 /*
607  * Find the first empty cluster
608  */
609 static int find_empty_cluster(fsdata *mydata)
610 {
611         __u32 fat_val, entry = 3;
612
613         while (1) {
614                 fat_val = get_fatent(mydata, entry);
615                 if (fat_val == 0)
616                         break;
617                 entry++;
618         }
619
620         return entry;
621 }
622
623 /*
624  * Allocate a cluster for additional directory entries
625  */
626 static int new_dir_table(fat_itr *itr)
627 {
628         fsdata *mydata = itr->fsdata;
629         int dir_newclust = 0;
630         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
631
632         dir_newclust = find_empty_cluster(mydata);
633         set_fatent_value(mydata, itr->clust, dir_newclust);
634         if (mydata->fatsize == 32)
635                 set_fatent_value(mydata, dir_newclust, 0xffffff8);
636         else if (mydata->fatsize == 16)
637                 set_fatent_value(mydata, dir_newclust, 0xfff8);
638         else if (mydata->fatsize == 12)
639                 set_fatent_value(mydata, dir_newclust, 0xff8);
640
641         itr->clust = dir_newclust;
642         itr->next_clust = dir_newclust;
643
644         if (flush_dirty_fat_buffer(mydata) < 0)
645                 return -1;
646
647         memset(itr->block, 0x00, bytesperclust);
648
649         itr->dent = (dir_entry *)itr->block;
650         itr->last_cluster = 1;
651         itr->remaining = bytesperclust / sizeof(dir_entry) - 1;
652
653         return 0;
654 }
655
656 /*
657  * Set empty cluster from 'entry' to the end of a file
658  */
659 static int clear_fatent(fsdata *mydata, __u32 entry)
660 {
661         __u32 fat_val;
662
663         while (!CHECK_CLUST(entry, mydata->fatsize)) {
664                 fat_val = get_fatent(mydata, entry);
665                 if (fat_val != 0)
666                         set_fatent_value(mydata, entry, 0);
667                 else
668                         break;
669
670                 entry = fat_val;
671         }
672
673         /* Flush fat buffer */
674         if (flush_dirty_fat_buffer(mydata) < 0)
675                 return -1;
676
677         return 0;
678 }
679
680 /*
681  * Set start cluster in directory entry
682  */
683 static void set_start_cluster(const fsdata *mydata, dir_entry *dentptr,
684                               __u32 start_cluster)
685 {
686         if (mydata->fatsize == 32)
687                 dentptr->starthi =
688                         cpu_to_le16((start_cluster & 0xffff0000) >> 16);
689         dentptr->start = cpu_to_le16(start_cluster & 0xffff);
690 }
691
692 /*
693  * Check whether adding a file makes the file system to
694  * exceed the size of the block device
695  * Return -1 when overflow occurs, otherwise return 0
696  */
697 static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size)
698 {
699         __u32 startsect, sect_num, offset;
700
701         if (clustnum > 0)
702                 startsect = clust_to_sect(mydata, clustnum);
703         else
704                 startsect = mydata->rootdir_sect;
705
706         sect_num = div_u64_rem(size, mydata->sect_size, &offset);
707
708         if (offset != 0)
709                 sect_num++;
710
711         if (startsect + sect_num > total_sector)
712                 return -1;
713         return 0;
714 }
715
716 /*
717  * Write at most 'maxsize' bytes from 'buffer' into
718  * the file associated with 'dentptr'
719  * Update the number of bytes written in *gotsize and return 0
720  * or return -1 on fatal errors.
721  */
722 static int
723 set_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos, __u8 *buffer,
724              loff_t maxsize, loff_t *gotsize)
725 {
726         unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
727         __u32 curclust = START(dentptr);
728         __u32 endclust = 0, newclust = 0;
729         u64 cur_pos, filesize;
730         loff_t offset, actsize, wsize;
731
732         *gotsize = 0;
733         filesize = pos + maxsize;
734
735         debug("%llu bytes\n", filesize);
736
737         if (!filesize) {
738                 if (!curclust)
739                         return 0;
740                 if (!CHECK_CLUST(curclust, mydata->fatsize) ||
741                     IS_LAST_CLUST(curclust, mydata->fatsize)) {
742                         clear_fatent(mydata, curclust);
743                         set_start_cluster(mydata, dentptr, 0);
744                         return 0;
745                 }
746                 debug("curclust: 0x%x\n", curclust);
747                 debug("Invalid FAT entry\n");
748                 return -1;
749         }
750
751         if (!curclust) {
752                 assert(pos == 0);
753                 goto set_clusters;
754         }
755
756         /* go to cluster at pos */
757         cur_pos = bytesperclust;
758         while (1) {
759                 if (pos <= cur_pos)
760                         break;
761                 if (IS_LAST_CLUST(curclust, mydata->fatsize))
762                         break;
763
764                 newclust = get_fatent(mydata, curclust);
765                 if (!IS_LAST_CLUST(newclust, mydata->fatsize) &&
766                     CHECK_CLUST(newclust, mydata->fatsize)) {
767                         debug("curclust: 0x%x\n", curclust);
768                         debug("Invalid FAT entry\n");
769                         return -1;
770                 }
771
772                 cur_pos += bytesperclust;
773                 curclust = newclust;
774         }
775         if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
776                 assert(pos == cur_pos);
777                 goto set_clusters;
778         }
779
780         assert(pos < cur_pos);
781         cur_pos -= bytesperclust;
782
783         /* overwrite */
784         assert(IS_LAST_CLUST(curclust, mydata->fatsize) ||
785                !CHECK_CLUST(curclust, mydata->fatsize));
786
787         while (1) {
788                 /* search for allocated consecutive clusters */
789                 actsize = bytesperclust;
790                 endclust = curclust;
791                 while (1) {
792                         if (filesize <= (cur_pos + actsize))
793                                 break;
794
795                         newclust = get_fatent(mydata, endclust);
796
797                         if (newclust != endclust + 1)
798                                 break;
799                         if (IS_LAST_CLUST(newclust, mydata->fatsize))
800                                 break;
801                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
802                                 debug("curclust: 0x%x\n", curclust);
803                                 debug("Invalid FAT entry\n");
804                                 return -1;
805                         }
806
807                         actsize += bytesperclust;
808                         endclust = newclust;
809                 }
810
811                 /* overwrite to <curclust..endclust> */
812                 if (pos < cur_pos)
813                         offset = 0;
814                 else
815                         offset = pos - cur_pos;
816                 wsize = min_t(unsigned long long, actsize, filesize - cur_pos);
817                 wsize -= offset;
818
819                 if (get_set_cluster(mydata, curclust, offset,
820                                     buffer, wsize, &actsize)) {
821                         printf("Error get-and-setting cluster\n");
822                         return -1;
823                 }
824                 buffer += wsize;
825                 *gotsize += wsize;
826                 cur_pos += offset + wsize;
827
828                 if (filesize <= cur_pos)
829                         break;
830
831                 if (IS_LAST_CLUST(newclust, mydata->fatsize))
832                         /* no more clusters */
833                         break;
834
835                 curclust = newclust;
836         }
837
838         if (filesize <= cur_pos) {
839                 /* no more write */
840                 newclust = get_fatent(mydata, endclust);
841                 if (!IS_LAST_CLUST(newclust, mydata->fatsize)) {
842                         /* truncate the rest */
843                         clear_fatent(mydata, newclust);
844
845                         /* Mark end of file in FAT */
846                         if (mydata->fatsize == 12)
847                                 newclust = 0xfff;
848                         else if (mydata->fatsize == 16)
849                                 newclust = 0xffff;
850                         else if (mydata->fatsize == 32)
851                                 newclust = 0xfffffff;
852                         set_fatent_value(mydata, endclust, newclust);
853                 }
854
855                 return 0;
856         }
857
858         curclust = endclust;
859         filesize -= cur_pos;
860         assert(!do_div(cur_pos, bytesperclust));
861
862 set_clusters:
863         /* allocate and write */
864         assert(!pos);
865
866         /* Assure that curclust is valid */
867         if (!curclust) {
868                 curclust = find_empty_cluster(mydata);
869                 set_start_cluster(mydata, dentptr, curclust);
870         } else {
871                 newclust = get_fatent(mydata, curclust);
872
873                 if (IS_LAST_CLUST(newclust, mydata->fatsize)) {
874                         newclust = determine_fatent(mydata, curclust);
875                         set_fatent_value(mydata, curclust, newclust);
876                         curclust = newclust;
877                 } else {
878                         debug("error: something wrong\n");
879                         return -1;
880                 }
881         }
882
883         /* TODO: already partially written */
884         if (check_overflow(mydata, curclust, filesize)) {
885                 printf("Error: no space left: %llu\n", filesize);
886                 return -1;
887         }
888
889         actsize = bytesperclust;
890         endclust = curclust;
891         do {
892                 /* search for consecutive clusters */
893                 while (actsize < filesize) {
894                         newclust = determine_fatent(mydata, endclust);
895
896                         if ((newclust - 1) != endclust)
897                                 /* write to <curclust..endclust> */
898                                 goto getit;
899
900                         if (CHECK_CLUST(newclust, mydata->fatsize)) {
901                                 debug("newclust: 0x%x\n", newclust);
902                                 debug("Invalid FAT entry\n");
903                                 return 0;
904                         }
905                         endclust = newclust;
906                         actsize += bytesperclust;
907                 }
908
909                 /* set remaining bytes */
910                 actsize = filesize;
911                 if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) {
912                         debug("error: writing cluster\n");
913                         return -1;
914                 }
915                 *gotsize += actsize;
916
917                 /* Mark end of file in FAT */
918                 if (mydata->fatsize == 12)
919                         newclust = 0xfff;
920                 else if (mydata->fatsize == 16)
921                         newclust = 0xffff;
922                 else if (mydata->fatsize == 32)
923                         newclust = 0xfffffff;
924                 set_fatent_value(mydata, endclust, newclust);
925
926                 return 0;
927 getit:
928                 if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) {
929                         debug("error: writing cluster\n");
930                         return -1;
931                 }
932                 *gotsize += actsize;
933                 filesize -= actsize;
934                 buffer += actsize;
935
936                 if (CHECK_CLUST(newclust, mydata->fatsize)) {
937                         debug("newclust: 0x%x\n", newclust);
938                         debug("Invalid FAT entry\n");
939                         return 0;
940                 }
941                 actsize = bytesperclust;
942                 curclust = endclust = newclust;
943         } while (1);
944
945         return 0;
946 }
947
948 /*
949  * Fill dir_entry
950  */
951 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
952         const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
953 {
954         set_start_cluster(mydata, dentptr, start_cluster);
955         dentptr->size = cpu_to_le32(size);
956
957         dentptr->attr = attr;
958
959         set_name(dentptr, filename);
960 }
961
962 /*
963  * Find a directory entry based on filename or start cluster number
964  * If the directory entry is not found,
965  * the new position for writing a directory entry will be returned
966  */
967 static dir_entry *find_directory_entry(fat_itr *itr, char *filename)
968 {
969         int match = 0;
970
971         while (fat_itr_next(itr)) {
972                 /* check both long and short name: */
973                 if (!strcasecmp(filename, itr->name))
974                         match = 1;
975                 else if (itr->name != itr->s_name &&
976                          !strcasecmp(filename, itr->s_name))
977                         match = 1;
978
979                 if (!match)
980                         continue;
981
982                 if (itr->dent->name[0] == '\0')
983                         return NULL;
984                 else
985                         return itr->dent;
986         }
987
988         /* allocate a cluster for more entries */
989         if (!itr->dent &&
990             (!itr->is_root || itr->fsdata->fatsize == 32) &&
991             new_dir_table(itr))
992                 /* indicate that allocating dent failed */
993                 itr->dent = NULL;
994
995         return NULL;
996 }
997
998 static int split_filename(char *filename, char **dirname, char **basename)
999 {
1000         char *p, *last_slash, *last_slash_cont;
1001
1002 again:
1003         p = filename;
1004         last_slash = NULL;
1005         last_slash_cont = NULL;
1006         while (*p) {
1007                 if (ISDIRDELIM(*p)) {
1008                         last_slash = p;
1009                         last_slash_cont = p;
1010                         /* continuous slashes */
1011                         while (ISDIRDELIM(*p))
1012                                 last_slash_cont = p++;
1013                         if (!*p)
1014                                 break;
1015                 }
1016                 p++;
1017         }
1018
1019         if (last_slash) {
1020                 if (last_slash_cont == (filename + strlen(filename) - 1)) {
1021                         /* remove trailing slashes */
1022                         *last_slash = '\0';
1023                         goto again;
1024                 }
1025
1026                 if (last_slash == filename) {
1027                         /* avoid ""(null) directory */
1028                         *dirname = "/";
1029                 } else {
1030                         *last_slash = '\0';
1031                         *dirname = filename;
1032                 }
1033
1034                 *last_slash_cont = '\0';
1035                 *basename = last_slash_cont + 1;
1036         } else {
1037                 *dirname = "/"; /* root by default */
1038                 *basename = filename;
1039         }
1040
1041         return 0;
1042 }
1043
1044 /**
1045  * normalize_longname() - check long file name and convert to lower case
1046  *
1047  * We assume here that the FAT file system is using an 8bit code page.
1048  * Linux typically uses CP437, EDK2 assumes CP1250.
1049  *
1050  * @l_filename: preallocated buffer receiving the normalized name
1051  * @filename:   filename to normalize
1052  * Return:      0 on success, -1 on failure
1053  */
1054 static int normalize_longname(char *l_filename, const char *filename)
1055 {
1056         const char *p, illegal[] = "<>:\"/\\|?*";
1057
1058         if (strlen(filename) >= VFAT_MAXLEN_BYTES)
1059                 return -1;
1060
1061         for (p = filename; *p; ++p) {
1062                 if ((unsigned char)*p < 0x20)
1063                         return -1;
1064                 if (strchr(illegal, *p))
1065                         return -1;
1066         }
1067
1068         strcpy(l_filename, filename);
1069         downcase(l_filename, VFAT_MAXLEN_BYTES);
1070
1071         return 0;
1072 }
1073
1074 int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
1075                       loff_t size, loff_t *actwrite)
1076 {
1077         dir_entry *retdent;
1078         fsdata datablock = { .fatbuf = NULL, };
1079         fsdata *mydata = &datablock;
1080         fat_itr *itr = NULL;
1081         int ret = -1;
1082         char *filename_copy, *parent, *basename;
1083         char l_filename[VFAT_MAXLEN_BYTES];
1084
1085         debug("writing %s\n", filename);
1086
1087         filename_copy = strdup(filename);
1088         if (!filename_copy)
1089                 return -ENOMEM;
1090
1091         split_filename(filename_copy, &parent, &basename);
1092         if (!strlen(basename)) {
1093                 ret = -EINVAL;
1094                 goto exit;
1095         }
1096
1097         filename = basename;
1098         if (normalize_longname(l_filename, filename)) {
1099                 printf("FAT: illegal filename (%s)\n", filename);
1100                 ret = -EINVAL;
1101                 goto exit;
1102         }
1103
1104         itr = malloc_cache_aligned(sizeof(fat_itr));
1105         if (!itr) {
1106                 ret = -ENOMEM;
1107                 goto exit;
1108         }
1109
1110         ret = fat_itr_root(itr, &datablock);
1111         if (ret)
1112                 goto exit;
1113
1114         total_sector = datablock.total_sect;
1115
1116         ret = fat_itr_resolve(itr, parent, TYPE_DIR);
1117         if (ret) {
1118                 printf("%s: doesn't exist (%d)\n", parent, ret);
1119                 goto exit;
1120         }
1121
1122         retdent = find_directory_entry(itr, l_filename);
1123
1124         if (retdent) {
1125                 if (fat_itr_isdir(itr)) {
1126                         ret = -EISDIR;
1127                         goto exit;
1128                 }
1129
1130                 /* A file exists */
1131                 if (pos == -1)
1132                         /* Append to the end */
1133                         pos = FAT2CPU32(retdent->size);
1134                 if (pos > retdent->size) {
1135                         /* No hole allowed */
1136                         ret = -EINVAL;
1137                         goto exit;
1138                 }
1139
1140                 /* Update file size in a directory entry */
1141                 retdent->size = cpu_to_le32(pos + size);
1142         } else {
1143                 /* Create a new file */
1144
1145                 if (itr->is_root) {
1146                         /* root dir cannot have "." or ".." */
1147                         if (!strcmp(l_filename, ".") ||
1148                             !strcmp(l_filename, "..")) {
1149                                 ret = -EINVAL;
1150                                 goto exit;
1151                         }
1152                 }
1153
1154                 if (!itr->dent) {
1155                         printf("Error: allocating new dir entry\n");
1156                         ret = -EIO;
1157                         goto exit;
1158                 }
1159
1160                 if (pos) {
1161                         /* No hole allowed */
1162                         ret = -EINVAL;
1163                         goto exit;
1164                 }
1165
1166                 memset(itr->dent, 0, sizeof(*itr->dent));
1167
1168                 /* Calculate checksum for short name */
1169                 set_name(itr->dent, filename);
1170
1171                 /* Set long name entries */
1172                 if (fill_dir_slot(itr, filename)) {
1173                         ret = -EIO;
1174                         goto exit;
1175                 }
1176
1177                 /* Set short name entry */
1178                 fill_dentry(itr->fsdata, itr->dent, filename, 0, size, 0x20);
1179
1180                 retdent = itr->dent;
1181         }
1182
1183         ret = set_contents(mydata, retdent, pos, buffer, size, actwrite);
1184         if (ret < 0) {
1185                 printf("Error: writing contents\n");
1186                 ret = -EIO;
1187                 goto exit;
1188         }
1189         debug("attempt to write 0x%llx bytes\n", *actwrite);
1190
1191         /* Flush fat buffer */
1192         ret = flush_dirty_fat_buffer(mydata);
1193         if (ret) {
1194                 printf("Error: flush fat buffer\n");
1195                 ret = -EIO;
1196                 goto exit;
1197         }
1198
1199         /* Write directory table to device */
1200         ret = flush_dir(itr);
1201         if (ret) {
1202                 printf("Error: writing directory entry\n");
1203                 ret = -EIO;
1204         }
1205
1206 exit:
1207         free(filename_copy);
1208         free(mydata->fatbuf);
1209         free(itr);
1210         return ret;
1211 }
1212
1213 int file_fat_write(const char *filename, void *buffer, loff_t offset,
1214                    loff_t maxsize, loff_t *actwrite)
1215 {
1216         return file_fat_write_at(filename, offset, buffer, maxsize, actwrite);
1217 }
1218
1219 static int fat_dir_entries(fat_itr *itr)
1220 {
1221         fat_itr *dirs;
1222         fsdata fsdata = { .fatbuf = NULL, }, *mydata = &fsdata;
1223                                                 /* for FATBUFSIZE */
1224         int count;
1225
1226         dirs = malloc_cache_aligned(sizeof(fat_itr));
1227         if (!dirs) {
1228                 debug("Error: allocating memory\n");
1229                 count = -ENOMEM;
1230                 goto exit;
1231         }
1232
1233         /* duplicate fsdata */
1234         fat_itr_child(dirs, itr);
1235         fsdata = *dirs->fsdata;
1236
1237         /* allocate local fat buffer */
1238         fsdata.fatbuf = malloc_cache_aligned(FATBUFSIZE);
1239         if (!fsdata.fatbuf) {
1240                 debug("Error: allocating memory\n");
1241                 count = -ENOMEM;
1242                 goto exit;
1243         }
1244         fsdata.fatbufnum = -1;
1245         dirs->fsdata = &fsdata;
1246
1247         for (count = 0; fat_itr_next(dirs); count++)
1248                 ;
1249
1250 exit:
1251         free(fsdata.fatbuf);
1252         free(dirs);
1253         return count;
1254 }
1255
1256 static int delete_dentry(fat_itr *itr)
1257 {
1258         fsdata *mydata = itr->fsdata;
1259         dir_entry *dentptr = itr->dent;
1260
1261         /* free cluster blocks */
1262         clear_fatent(mydata, START(dentptr));
1263         if (flush_dirty_fat_buffer(mydata) < 0) {
1264                 printf("Error: flush fat buffer\n");
1265                 return -EIO;
1266         }
1267
1268         /*
1269          * update a directory entry
1270          * TODO:
1271          *  - long file name support
1272          *  - find and mark the "new" first invalid entry as name[0]=0x00
1273          */
1274         memset(dentptr, 0, sizeof(*dentptr));
1275         dentptr->name[0] = 0xe5;
1276
1277         if (flush_dir(itr)) {
1278                 printf("error: writing directory entry\n");
1279                 return -EIO;
1280         }
1281
1282         return 0;
1283 }
1284
1285 int fat_unlink(const char *filename)
1286 {
1287         fsdata fsdata = { .fatbuf = NULL, };
1288         fat_itr *itr = NULL;
1289         int n_entries, ret;
1290         char *filename_copy, *dirname, *basename;
1291
1292         filename_copy = strdup(filename);
1293         if (!filename_copy) {
1294                 printf("Error: allocating memory\n");
1295                 ret = -ENOMEM;
1296                 goto exit;
1297         }
1298         split_filename(filename_copy, &dirname, &basename);
1299
1300         if (!strcmp(dirname, "/") && !strcmp(basename, "")) {
1301                 printf("Error: cannot remove root\n");
1302                 ret = -EINVAL;
1303                 goto exit;
1304         }
1305
1306         itr = malloc_cache_aligned(sizeof(fat_itr));
1307         if (!itr) {
1308                 printf("Error: allocating memory\n");
1309                 ret = -ENOMEM;
1310                 goto exit;
1311         }
1312
1313         ret = fat_itr_root(itr, &fsdata);
1314         if (ret)
1315                 goto exit;
1316
1317         total_sector = fsdata.total_sect;
1318
1319         ret = fat_itr_resolve(itr, dirname, TYPE_DIR);
1320         if (ret) {
1321                 printf("%s: doesn't exist (%d)\n", dirname, ret);
1322                 ret = -ENOENT;
1323                 goto exit;
1324         }
1325
1326         if (!find_directory_entry(itr, basename)) {
1327                 printf("%s: doesn't exist\n", basename);
1328                 ret = -ENOENT;
1329                 goto exit;
1330         }
1331
1332         if (fat_itr_isdir(itr)) {
1333                 n_entries = fat_dir_entries(itr);
1334                 if (n_entries < 0) {
1335                         ret = n_entries;
1336                         goto exit;
1337                 }
1338                 if (n_entries > 2) {
1339                         printf("Error: directory is not empty: %d\n",
1340                                n_entries);
1341                         ret = -EINVAL;
1342                         goto exit;
1343                 }
1344         }
1345
1346         ret = delete_dentry(itr);
1347
1348 exit:
1349         free(fsdata.fatbuf);
1350         free(itr);
1351         free(filename_copy);
1352
1353         return ret;
1354 }
1355
1356 int fat_mkdir(const char *new_dirname)
1357 {
1358         dir_entry *retdent;
1359         fsdata datablock = { .fatbuf = NULL, };
1360         fsdata *mydata = &datablock;
1361         fat_itr *itr = NULL;
1362         char *dirname_copy, *parent, *dirname;
1363         char l_dirname[VFAT_MAXLEN_BYTES];
1364         int ret = -1;
1365         loff_t actwrite;
1366         unsigned int bytesperclust;
1367         dir_entry *dotdent = NULL;
1368
1369         dirname_copy = strdup(new_dirname);
1370         if (!dirname_copy)
1371                 goto exit;
1372
1373         split_filename(dirname_copy, &parent, &dirname);
1374         if (!strlen(dirname)) {
1375                 ret = -EINVAL;
1376                 goto exit;
1377         }
1378
1379         if (normalize_longname(l_dirname, dirname)) {
1380                 printf("FAT: illegal filename (%s)\n", dirname);
1381                 ret = -EINVAL;
1382                 goto exit;
1383         }
1384
1385         itr = malloc_cache_aligned(sizeof(fat_itr));
1386         if (!itr) {
1387                 ret = -ENOMEM;
1388                 goto exit;
1389         }
1390
1391         ret = fat_itr_root(itr, &datablock);
1392         if (ret)
1393                 goto exit;
1394
1395         total_sector = datablock.total_sect;
1396
1397         ret = fat_itr_resolve(itr, parent, TYPE_DIR);
1398         if (ret) {
1399                 printf("%s: doesn't exist (%d)\n", parent, ret);
1400                 goto exit;
1401         }
1402
1403         retdent = find_directory_entry(itr, l_dirname);
1404
1405         if (retdent) {
1406                 printf("%s: already exists\n", l_dirname);
1407                 ret = -EEXIST;
1408                 goto exit;
1409         } else {
1410                 if (itr->is_root) {
1411                         /* root dir cannot have "." or ".." */
1412                         if (!strcmp(l_dirname, ".") ||
1413                             !strcmp(l_dirname, "..")) {
1414                                 ret = -EINVAL;
1415                                 goto exit;
1416                         }
1417                 }
1418
1419                 if (!itr->dent) {
1420                         printf("Error: allocating new dir entry\n");
1421                         ret = -EIO;
1422                         goto exit;
1423                 }
1424
1425                 memset(itr->dent, 0, sizeof(*itr->dent));
1426
1427                 /* Set short name to set alias checksum field in dir_slot */
1428                 set_name(itr->dent, dirname);
1429                 fill_dir_slot(itr, dirname);
1430
1431                 /* Set attribute as archive for regular file */
1432                 fill_dentry(itr->fsdata, itr->dent, dirname, 0, 0,
1433                             ATTR_DIR | ATTR_ARCH);
1434
1435                 retdent = itr->dent;
1436         }
1437
1438         /* Default entries */
1439         bytesperclust = mydata->clust_size * mydata->sect_size;
1440         dotdent = malloc_cache_aligned(bytesperclust);
1441         if (!dotdent) {
1442                 ret = -ENOMEM;
1443                 goto exit;
1444         }
1445         memset(dotdent, 0, bytesperclust);
1446
1447         memcpy(dotdent[0].name, ".       ", 8);
1448         memcpy(dotdent[0].ext, "   ", 3);
1449         dotdent[0].attr = ATTR_DIR | ATTR_ARCH;
1450
1451         memcpy(dotdent[1].name, "..      ", 8);
1452         memcpy(dotdent[1].ext, "   ", 3);
1453         dotdent[1].attr = ATTR_DIR | ATTR_ARCH;
1454         set_start_cluster(mydata, &dotdent[1], itr->start_clust);
1455
1456         ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent,
1457                            bytesperclust, &actwrite);
1458         if (ret < 0) {
1459                 printf("Error: writing contents\n");
1460                 goto exit;
1461         }
1462         /* Write twice for "." */
1463         set_start_cluster(mydata, &dotdent[0], START(retdent));
1464         ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent,
1465                            bytesperclust, &actwrite);
1466         if (ret < 0) {
1467                 printf("Error: writing contents\n");
1468                 goto exit;
1469         }
1470
1471         /* Flush fat buffer */
1472         ret = flush_dirty_fat_buffer(mydata);
1473         if (ret) {
1474                 printf("Error: flush fat buffer\n");
1475                 goto exit;
1476         }
1477
1478         /* Write directory table to device */
1479         ret = flush_dir(itr);
1480         if (ret)
1481                 printf("Error: writing directory entry\n");
1482
1483 exit:
1484         free(dirname_copy);
1485         free(mydata->fatbuf);
1486         free(itr);
1487         free(dotdent);
1488         return ret;
1489 }