1427 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * linux/fs/fat/dir.c4 *5 * directory handling functions for fat-based filesystems6 *7 * Written 1992,1993 by Werner Almesberger8 *9 * Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>10 *11 * VFAT extensions by Gordon Chaffee <chaffee@plateau.cs.berkeley.edu>12 * Merged with msdos fs by Henrik Storner <storner@osiris.ping.dk>13 * Rewritten for constant inumbers. Plugged buffer overrun in readdir(). AV14 * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>15 */16 17#include <linux/slab.h>18#include <linux/compat.h>19#include <linux/uaccess.h>20#include <linux/iversion.h>21#include "fat.h"22 23/*24 * Maximum buffer size of short name.25 * [(MSDOS_NAME + '.') * max one char + nul]26 * For msdos style, ['.' (hidden) + MSDOS_NAME + '.' + nul]27 */28#define FAT_MAX_SHORT_SIZE ((MSDOS_NAME + 1) * NLS_MAX_CHARSET_SIZE + 1)29/*30 * Maximum buffer size of unicode chars from slots.31 * [(max longname slots * 13 (size in a slot) + nul) * sizeof(wchar_t)]32 */33#define FAT_MAX_UNI_CHARS ((MSDOS_SLOTS - 1) * 13 + 1)34#define FAT_MAX_UNI_SIZE (FAT_MAX_UNI_CHARS * sizeof(wchar_t))35 36static inline unsigned char fat_tolower(unsigned char c)37{38 return ((c >= 'A') && (c <= 'Z')) ? c+32 : c;39}40 41static inline loff_t fat_make_i_pos(struct super_block *sb,42 struct buffer_head *bh,43 struct msdos_dir_entry *de)44{45 return ((loff_t)bh->b_blocknr << MSDOS_SB(sb)->dir_per_block_bits)46 | (de - (struct msdos_dir_entry *)bh->b_data);47}48 49static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,50 sector_t phys)51{52 struct super_block *sb = dir->i_sb;53 struct msdos_sb_info *sbi = MSDOS_SB(sb);54 struct buffer_head *bh;55 int sec;56 57 /* This is not a first sector of cluster, or sec_per_clus == 1 */58 if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)59 return;60 /* root dir of FAT12/FAT16 */61 if (!is_fat32(sbi) && (dir->i_ino == MSDOS_ROOT_INO))62 return;63 64 bh = sb_find_get_block(sb, phys);65 if (bh == NULL || !buffer_uptodate(bh)) {66 for (sec = 0; sec < sbi->sec_per_clus; sec++)67 sb_breadahead(sb, phys + sec);68 }69 brelse(bh);70}71 72/* Returns the inode number of the directory entry at offset pos. If bh is73 non-NULL, it is brelse'd before. Pos is incremented. The buffer header is74 returned in bh.75 AV. Most often we do it item-by-item. Makes sense to optimize.76 AV. OK, there we go: if both bh and de are non-NULL we assume that we just77 AV. want the next entry (took one explicit de=NULL in vfat/namei.c).78 AV. It's done in fat_get_entry() (inlined), here the slow case lives.79 AV. Additionally, when we return -1 (i.e. reached the end of directory)80 AV. we make bh NULL.81 */82static int fat__get_entry(struct inode *dir, loff_t *pos,83 struct buffer_head **bh, struct msdos_dir_entry **de)84{85 struct super_block *sb = dir->i_sb;86 sector_t phys, iblock;87 unsigned long mapped_blocks;88 int err, offset;89 90next:91 brelse(*bh);92 *bh = NULL;93 iblock = *pos >> sb->s_blocksize_bits;94 err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0, false);95 if (err || !phys)96 return -1; /* beyond EOF or error */97 98 fat_dir_readahead(dir, iblock, phys);99 100 *bh = sb_bread(sb, phys);101 if (*bh == NULL) {102 fat_msg_ratelimit(sb, KERN_ERR,103 "Directory bread(block %llu) failed", (llu)phys);104 /* skip this block */105 *pos = (iblock + 1) << sb->s_blocksize_bits;106 goto next;107 }108 109 offset = *pos & (sb->s_blocksize - 1);110 *pos += sizeof(struct msdos_dir_entry);111 *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);112 113 return 0;114}115 116static inline int fat_get_entry(struct inode *dir, loff_t *pos,117 struct buffer_head **bh,118 struct msdos_dir_entry **de)119{120 /* Fast stuff first */121 if (*bh && *de &&122 (*de - (struct msdos_dir_entry *)(*bh)->b_data) <123 MSDOS_SB(dir->i_sb)->dir_per_block - 1) {124 *pos += sizeof(struct msdos_dir_entry);125 (*de)++;126 return 0;127 }128 return fat__get_entry(dir, pos, bh, de);129}130 131/*132 * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII.133 * If uni_xlate is enabled and we can't get a 1:1 conversion, use a134 * colon as an escape character since it is normally invalid on the vfat135 * filesystem. The following four characters are the hexadecimal digits136 * of Unicode value. This lets us do a full dump and restore of Unicode137 * filenames. We could get into some trouble with long Unicode names,138 * but ignore that right now.139 * Ahem... Stack smashing in ring 0 isn't fun. Fixed.140 */141static int uni16_to_x8(struct super_block *sb, unsigned char *ascii,142 const wchar_t *uni, int len, struct nls_table *nls)143{144 int uni_xlate = MSDOS_SB(sb)->options.unicode_xlate;145 const wchar_t *ip;146 wchar_t ec;147 unsigned char *op;148 int charlen;149 150 ip = uni;151 op = ascii;152 153 while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {154 ec = *ip++;155 charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE);156 if (charlen > 0) {157 op += charlen;158 len -= charlen;159 } else {160 if (uni_xlate == 1) {161 *op++ = ':';162 op = hex_byte_pack(op, ec >> 8);163 op = hex_byte_pack(op, ec);164 len -= 5;165 } else {166 *op++ = '?';167 len--;168 }169 }170 }171 172 if (unlikely(*ip)) {173 fat_msg(sb, KERN_WARNING,174 "filename was truncated while converting.");175 }176 177 *op = 0;178 return op - ascii;179}180 181static inline int fat_uni_to_x8(struct super_block *sb, const wchar_t *uni,182 unsigned char *buf, int size)183{184 struct msdos_sb_info *sbi = MSDOS_SB(sb);185 if (sbi->options.utf8)186 return utf16s_to_utf8s(uni, FAT_MAX_UNI_CHARS,187 UTF16_HOST_ENDIAN, buf, size);188 else189 return uni16_to_x8(sb, buf, uni, size, sbi->nls_io);190}191 192static inline int193fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)194{195 int charlen;196 197 charlen = t->char2uni(c, clen, uni);198 if (charlen < 0) {199 *uni = 0x003f; /* a question mark */200 charlen = 1;201 }202 return charlen;203}204 205static inline int206fat_short2lower_uni(struct nls_table *t, unsigned char *c,207 int clen, wchar_t *uni)208{209 int charlen;210 wchar_t wc;211 212 charlen = t->char2uni(c, clen, &wc);213 if (charlen < 0) {214 *uni = 0x003f; /* a question mark */215 charlen = 1;216 } else if (charlen <= 1) {217 unsigned char nc = t->charset2lower[*c];218 219 if (!nc)220 nc = *c;221 222 charlen = t->char2uni(&nc, 1, uni);223 if (charlen < 0) {224 *uni = 0x003f; /* a question mark */225 charlen = 1;226 }227 } else228 *uni = wc;229 230 return charlen;231}232 233static inline int234fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,235 wchar_t *uni_buf, unsigned short opt, int lower)236{237 int len = 0;238 239 if (opt & VFAT_SFN_DISPLAY_LOWER)240 len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);241 else if (opt & VFAT_SFN_DISPLAY_WIN95)242 len = fat_short2uni(nls, buf, buf_size, uni_buf);243 else if (opt & VFAT_SFN_DISPLAY_WINNT) {244 if (lower)245 len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);246 else247 len = fat_short2uni(nls, buf, buf_size, uni_buf);248 } else249 len = fat_short2uni(nls, buf, buf_size, uni_buf);250 251 return len;252}253 254static inline int fat_name_match(struct msdos_sb_info *sbi,255 const unsigned char *a, int a_len,256 const unsigned char *b, int b_len)257{258 if (a_len != b_len)259 return 0;260 261 if (sbi->options.name_check != 's')262 return !nls_strnicmp(sbi->nls_io, a, b, a_len);263 else264 return !memcmp(a, b, a_len);265}266 267enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };268 269/**270 * fat_parse_long - Parse extended directory entry.271 *272 * @dir: Pointer to the inode that represents the directory.273 * @pos: On input, contains the starting position to read from.274 * On output, updated with the new position.275 * @bh: Pointer to the buffer head that may be used for reading directory276 * entries. May be updated.277 * @de: On input, points to the current directory entry.278 * On output, points to the next directory entry.279 * @unicode: Pointer to a buffer where the parsed Unicode long filename will be280 * stored.281 * @nr_slots: Pointer to a variable that will store the number of longname282 * slots found.283 *284 * This function returns zero on success, negative value on error, or one of285 * the following:286 *287 * %PARSE_INVALID - Directory entry is invalid.288 * %PARSE_NOT_LONGNAME - Directory entry does not contain longname.289 * %PARSE_EOF - Directory has no more entries.290 */291static int fat_parse_long(struct inode *dir, loff_t *pos,292 struct buffer_head **bh, struct msdos_dir_entry **de,293 wchar_t **unicode, unsigned char *nr_slots)294{295 struct msdos_dir_slot *ds;296 unsigned char id, slot, slots, alias_checksum;297 298 if (!*unicode) {299 *unicode = __getname();300 if (!*unicode) {301 brelse(*bh);302 return -ENOMEM;303 }304 }305parse_long:306 ds = (struct msdos_dir_slot *)*de;307 id = ds->id;308 if (!(id & 0x40))309 return PARSE_INVALID;310 slots = id & ~0x40;311 if (slots > 20 || !slots) /* ceil(256 * 2 / 26) */312 return PARSE_INVALID;313 *nr_slots = slots;314 alias_checksum = ds->alias_checksum;315 316 slot = slots;317 while (1) {318 int offset;319 320 slot--;321 offset = slot * 13;322 fat16_towchar(*unicode + offset, ds->name0_4, 5);323 fat16_towchar(*unicode + offset + 5, ds->name5_10, 6);324 fat16_towchar(*unicode + offset + 11, ds->name11_12, 2);325 326 if (ds->id & 0x40)327 (*unicode)[offset + 13] = 0;328 if (fat_get_entry(dir, pos, bh, de) < 0)329 return PARSE_EOF;330 if (slot == 0)331 break;332 ds = (struct msdos_dir_slot *)*de;333 if (ds->attr != ATTR_EXT)334 return PARSE_NOT_LONGNAME;335 if ((ds->id & ~0x40) != slot)336 goto parse_long;337 if (ds->alias_checksum != alias_checksum)338 goto parse_long;339 }340 if ((*de)->name[0] == DELETED_FLAG)341 return PARSE_INVALID;342 if ((*de)->attr == ATTR_EXT)343 goto parse_long;344 if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))345 return PARSE_INVALID;346 if (fat_checksum((*de)->name) != alias_checksum)347 *nr_slots = 0;348 349 return 0;350}351 352/**353 * fat_parse_short - Parse MS-DOS (short) directory entry.354 * @sb: superblock355 * @de: directory entry to parse356 * @name: FAT_MAX_SHORT_SIZE array in which to place extracted name357 * @dot_hidden: Nonzero == prepend '.' to names with ATTR_HIDDEN358 *359 * Returns the number of characters extracted into 'name'.360 */361static int fat_parse_short(struct super_block *sb,362 const struct msdos_dir_entry *de,363 unsigned char *name, int dot_hidden)364{365 const struct msdos_sb_info *sbi = MSDOS_SB(sb);366 int isvfat = sbi->options.isvfat;367 int nocase = sbi->options.nocase;368 unsigned short opt_shortname = sbi->options.shortname;369 struct nls_table *nls_disk = sbi->nls_disk;370 wchar_t uni_name[14];371 unsigned char c, work[MSDOS_NAME];372 unsigned char *ptname = name;373 int chi, chl, i, j, k;374 int dotoffset = 0;375 int name_len = 0, uni_len = 0;376 377 if (!isvfat && dot_hidden && (de->attr & ATTR_HIDDEN)) {378 *ptname++ = '.';379 dotoffset = 1;380 }381 382 memcpy(work, de->name, sizeof(work));383 /* For an explanation of the special treatment of 0x05 in384 * filenames, see msdos_format_name in namei_msdos.c385 */386 if (work[0] == 0x05)387 work[0] = 0xE5;388 389 /* Filename */390 for (i = 0, j = 0; i < 8;) {391 c = work[i];392 if (!c)393 break;394 chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,395 &uni_name[j++], opt_shortname,396 de->lcase & CASE_LOWER_BASE);397 if (chl <= 1) {398 if (!isvfat)399 ptname[i] = nocase ? c : fat_tolower(c);400 i++;401 if (c != ' ') {402 name_len = i;403 uni_len = j;404 }405 } else {406 uni_len = j;407 if (isvfat)408 i += min(chl, 8-i);409 else {410 for (chi = 0; chi < chl && i < 8; chi++, i++)411 ptname[i] = work[i];412 }413 if (chl)414 name_len = i;415 }416 }417 418 i = name_len;419 j = uni_len;420 fat_short2uni(nls_disk, ".", 1, &uni_name[j++]);421 if (!isvfat)422 ptname[i] = '.';423 i++;424 425 /* Extension */426 for (k = 8; k < MSDOS_NAME;) {427 c = work[k];428 if (!c)429 break;430 chl = fat_shortname2uni(nls_disk, &work[k], MSDOS_NAME - k,431 &uni_name[j++], opt_shortname,432 de->lcase & CASE_LOWER_EXT);433 if (chl <= 1) {434 k++;435 if (!isvfat)436 ptname[i] = nocase ? c : fat_tolower(c);437 i++;438 if (c != ' ') {439 name_len = i;440 uni_len = j;441 }442 } else {443 uni_len = j;444 if (isvfat) {445 int offset = min(chl, MSDOS_NAME-k);446 k += offset;447 i += offset;448 } else {449 for (chi = 0; chi < chl && k < MSDOS_NAME;450 chi++, i++, k++) {451 ptname[i] = work[k];452 }453 }454 if (chl)455 name_len = i;456 }457 }458 459 if (name_len > 0) {460 name_len += dotoffset;461 462 if (sbi->options.isvfat) {463 uni_name[uni_len] = 0x0000;464 name_len = fat_uni_to_x8(sb, uni_name, name,465 FAT_MAX_SHORT_SIZE);466 }467 }468 469 return name_len;470}471 472/*473 * Return values: negative -> error/not found, 0 -> found.474 */475int fat_search_long(struct inode *inode, const unsigned char *name,476 int name_len, struct fat_slot_info *sinfo)477{478 struct super_block *sb = inode->i_sb;479 struct msdos_sb_info *sbi = MSDOS_SB(sb);480 struct buffer_head *bh = NULL;481 struct msdos_dir_entry *de;482 unsigned char nr_slots;483 wchar_t *unicode = NULL;484 unsigned char bufname[FAT_MAX_SHORT_SIZE];485 loff_t cpos = 0;486 int err, len;487 488 err = -ENOENT;489 while (1) {490 if (fat_get_entry(inode, &cpos, &bh, &de) == -1)491 goto end_of_dir;492parse_record:493 nr_slots = 0;494 if (de->name[0] == DELETED_FLAG)495 continue;496 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))497 continue;498 if (de->attr != ATTR_EXT && IS_FREE(de->name))499 continue;500 if (de->attr == ATTR_EXT) {501 int status = fat_parse_long(inode, &cpos, &bh, &de,502 &unicode, &nr_slots);503 if (status < 0) {504 err = status;505 goto end_of_dir;506 } else if (status == PARSE_INVALID)507 continue;508 else if (status == PARSE_NOT_LONGNAME)509 goto parse_record;510 else if (status == PARSE_EOF)511 goto end_of_dir;512 }513 514 /* Never prepend '.' to hidden files here.515 * That is done only for msdos mounts (and only when516 * 'dotsOK=yes'); if we are executing here, it is in the517 * context of a vfat mount.518 */519 len = fat_parse_short(sb, de, bufname, 0);520 if (len == 0)521 continue;522 523 /* Compare shortname */524 if (fat_name_match(sbi, name, name_len, bufname, len))525 goto found;526 527 if (nr_slots) {528 void *longname = unicode + FAT_MAX_UNI_CHARS;529 int size = PATH_MAX - FAT_MAX_UNI_SIZE;530 531 /* Compare longname */532 len = fat_uni_to_x8(sb, unicode, longname, size);533 if (fat_name_match(sbi, name, name_len, longname, len))534 goto found;535 }536 }537 538found:539 nr_slots++; /* include the de */540 sinfo->slot_off = cpos - nr_slots * sizeof(*de);541 sinfo->nr_slots = nr_slots;542 sinfo->de = de;543 sinfo->bh = bh;544 sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);545 err = 0;546end_of_dir:547 if (unicode)548 __putname(unicode);549 550 return err;551}552EXPORT_SYMBOL_GPL(fat_search_long);553 554struct fat_ioctl_filldir_callback {555 struct dir_context ctx;556 void __user *dirent;557 int result;558 /* for dir ioctl */559 const char *longname;560 int long_len;561 const char *shortname;562 int short_len;563};564 565static int __fat_readdir(struct inode *inode, struct file *file,566 struct dir_context *ctx, int short_only,567 struct fat_ioctl_filldir_callback *both)568{569 struct super_block *sb = inode->i_sb;570 struct msdos_sb_info *sbi = MSDOS_SB(sb);571 struct buffer_head *bh;572 struct msdos_dir_entry *de;573 unsigned char nr_slots;574 wchar_t *unicode = NULL;575 unsigned char bufname[FAT_MAX_SHORT_SIZE];576 int isvfat = sbi->options.isvfat;577 const char *fill_name = NULL;578 int fake_offset = 0;579 loff_t cpos;580 int short_len = 0, fill_len = 0;581 int ret = 0;582 583 mutex_lock(&sbi->s_lock);584 585 cpos = ctx->pos;586 /* Fake . and .. for the root directory. */587 if (inode->i_ino == MSDOS_ROOT_INO) {588 if (!dir_emit_dots(file, ctx))589 goto out;590 if (ctx->pos == 2) {591 fake_offset = 1;592 cpos = 0;593 }594 }595 if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {596 ret = -ENOENT;597 goto out;598 }599 600 bh = NULL;601get_new:602 if (fat_get_entry(inode, &cpos, &bh, &de) == -1)603 goto end_of_dir;604parse_record:605 nr_slots = 0;606 /*607 * Check for long filename entry, but if short_only, we don't608 * need to parse long filename.609 */610 if (isvfat && !short_only) {611 if (de->name[0] == DELETED_FLAG)612 goto record_end;613 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))614 goto record_end;615 if (de->attr != ATTR_EXT && IS_FREE(de->name))616 goto record_end;617 } else {618 if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))619 goto record_end;620 }621 622 if (isvfat && de->attr == ATTR_EXT) {623 int status = fat_parse_long(inode, &cpos, &bh, &de,624 &unicode, &nr_slots);625 if (status < 0) {626 bh = NULL;627 ret = status;628 goto end_of_dir;629 } else if (status == PARSE_INVALID)630 goto record_end;631 else if (status == PARSE_NOT_LONGNAME)632 goto parse_record;633 else if (status == PARSE_EOF)634 goto end_of_dir;635 636 if (nr_slots) {637 void *longname = unicode + FAT_MAX_UNI_CHARS;638 int size = PATH_MAX - FAT_MAX_UNI_SIZE;639 int len = fat_uni_to_x8(sb, unicode, longname, size);640 641 fill_name = longname;642 fill_len = len;643 /* !both && !short_only, so we don't need shortname. */644 if (!both)645 goto start_filldir;646 647 short_len = fat_parse_short(sb, de, bufname,648 sbi->options.dotsOK);649 if (short_len == 0)650 goto record_end;651 /* hack for fat_ioctl_filldir() */652 both->longname = fill_name;653 both->long_len = fill_len;654 both->shortname = bufname;655 both->short_len = short_len;656 fill_name = NULL;657 fill_len = 0;658 goto start_filldir;659 }660 }661 662 short_len = fat_parse_short(sb, de, bufname, sbi->options.dotsOK);663 if (short_len == 0)664 goto record_end;665 666 fill_name = bufname;667 fill_len = short_len;668 669start_filldir:670 ctx->pos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);671 if (fake_offset && ctx->pos < 2)672 ctx->pos = 2;673 674 if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME)) {675 if (!dir_emit_dot(file, ctx))676 goto fill_failed;677 } else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {678 if (!dir_emit_dotdot(file, ctx))679 goto fill_failed;680 } else {681 unsigned long inum;682 loff_t i_pos = fat_make_i_pos(sb, bh, de);683 struct inode *tmp = fat_iget(sb, i_pos);684 if (tmp) {685 inum = tmp->i_ino;686 iput(tmp);687 } else688 inum = iunique(sb, MSDOS_ROOT_INO);689 if (!dir_emit(ctx, fill_name, fill_len, inum,690 (de->attr & ATTR_DIR) ? DT_DIR : DT_REG))691 goto fill_failed;692 }693 694record_end:695 fake_offset = 0;696 ctx->pos = cpos;697 goto get_new;698 699end_of_dir:700 if (fake_offset && cpos < 2)701 ctx->pos = 2;702 else703 ctx->pos = cpos;704fill_failed:705 brelse(bh);706 if (unicode)707 __putname(unicode);708out:709 mutex_unlock(&sbi->s_lock);710 711 return ret;712}713 714static int fat_readdir(struct file *file, struct dir_context *ctx)715{716 return __fat_readdir(file_inode(file), file, ctx, 0, NULL);717}718 719#define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type) \720static bool func(struct dir_context *ctx, const char *name, int name_len, \721 loff_t offset, u64 ino, unsigned int d_type) \722{ \723 struct fat_ioctl_filldir_callback *buf = \724 container_of(ctx, struct fat_ioctl_filldir_callback, ctx); \725 struct dirent_type __user *d1 = buf->dirent; \726 struct dirent_type __user *d2 = d1 + 1; \727 \728 if (buf->result) \729 return false; \730 buf->result++; \731 \732 if (name != NULL) { \733 /* dirent has only short name */ \734 if (name_len >= sizeof(d1->d_name)) \735 name_len = sizeof(d1->d_name) - 1; \736 \737 if (put_user(0, &d2->d_name[0]) || \738 put_user(0, &d2->d_reclen) || \739 copy_to_user(d1->d_name, name, name_len) || \740 put_user(0, d1->d_name + name_len) || \741 put_user(name_len, &d1->d_reclen)) \742 goto efault; \743 } else { \744 /* dirent has short and long name */ \745 const char *longname = buf->longname; \746 int long_len = buf->long_len; \747 const char *shortname = buf->shortname; \748 int short_len = buf->short_len; \749 \750 if (long_len >= sizeof(d1->d_name)) \751 long_len = sizeof(d1->d_name) - 1; \752 if (short_len >= sizeof(d1->d_name)) \753 short_len = sizeof(d1->d_name) - 1; \754 \755 if (copy_to_user(d2->d_name, longname, long_len) || \756 put_user(0, d2->d_name + long_len) || \757 put_user(long_len, &d2->d_reclen) || \758 put_user(ino, &d2->d_ino) || \759 put_user(offset, &d2->d_off) || \760 copy_to_user(d1->d_name, shortname, short_len) || \761 put_user(0, d1->d_name + short_len) || \762 put_user(short_len, &d1->d_reclen)) \763 goto efault; \764 } \765 return true; \766efault: \767 buf->result = -EFAULT; \768 return false; \769}770 771FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)772 773static int fat_ioctl_readdir(struct inode *inode, struct file *file,774 void __user *dirent, filldir_t filldir,775 int short_only, int both)776{777 struct fat_ioctl_filldir_callback buf = {778 .ctx.actor = filldir,779 .dirent = dirent780 };781 int ret;782 783 buf.dirent = dirent;784 buf.result = 0;785 inode_lock_shared(inode);786 buf.ctx.pos = file->f_pos;787 ret = -ENOENT;788 if (!IS_DEADDIR(inode)) {789 ret = __fat_readdir(inode, file, &buf.ctx,790 short_only, both ? &buf : NULL);791 file->f_pos = buf.ctx.pos;792 }793 inode_unlock_shared(inode);794 if (ret >= 0)795 ret = buf.result;796 return ret;797}798 799static long fat_dir_ioctl(struct file *filp, unsigned int cmd,800 unsigned long arg)801{802 struct inode *inode = file_inode(filp);803 struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;804 int short_only, both;805 806 switch (cmd) {807 case VFAT_IOCTL_READDIR_SHORT:808 short_only = 1;809 both = 0;810 break;811 case VFAT_IOCTL_READDIR_BOTH:812 short_only = 0;813 both = 1;814 break;815 default:816 return fat_generic_ioctl(filp, cmd, arg);817 }818 819 /*820 * Yes, we don't need this put_user() absolutely. However old821 * code didn't return the right value. So, app use this value,822 * in order to check whether it is EOF.823 */824 if (put_user(0, &d1->d_reclen))825 return -EFAULT;826 827 return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,828 short_only, both);829}830 831#ifdef CONFIG_COMPAT832#define VFAT_IOCTL_READDIR_BOTH32 _IOR('r', 1, struct compat_dirent[2])833#define VFAT_IOCTL_READDIR_SHORT32 _IOR('r', 2, struct compat_dirent[2])834 835FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)836 837static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,838 unsigned long arg)839{840 struct inode *inode = file_inode(filp);841 struct compat_dirent __user *d1 = compat_ptr(arg);842 int short_only, both;843 844 switch (cmd) {845 case VFAT_IOCTL_READDIR_SHORT32:846 short_only = 1;847 both = 0;848 break;849 case VFAT_IOCTL_READDIR_BOTH32:850 short_only = 0;851 both = 1;852 break;853 default:854 return fat_generic_ioctl(filp, cmd, (unsigned long)arg);855 }856 857 /*858 * Yes, we don't need this put_user() absolutely. However old859 * code didn't return the right value. So, app use this value,860 * in order to check whether it is EOF.861 */862 if (put_user(0, &d1->d_reclen))863 return -EFAULT;864 865 return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,866 short_only, both);867}868#endif /* CONFIG_COMPAT */869 870const struct file_operations fat_dir_operations = {871 .llseek = generic_file_llseek,872 .read = generic_read_dir,873 .iterate_shared = fat_readdir,874 .unlocked_ioctl = fat_dir_ioctl,875#ifdef CONFIG_COMPAT876 .compat_ioctl = fat_compat_dir_ioctl,877#endif878 .fsync = fat_file_fsync,879};880 881static int fat_get_short_entry(struct inode *dir, loff_t *pos,882 struct buffer_head **bh,883 struct msdos_dir_entry **de)884{885 while (fat_get_entry(dir, pos, bh, de) >= 0) {886 /* free entry or long name entry or volume label */887 if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))888 return 0;889 }890 return -ENOENT;891}892 893/*894 * The ".." entry can not provide the "struct fat_slot_info" information895 * for inode, nor a usable i_pos. So, this function provides some information896 * only.897 *898 * Since this function walks through the on-disk inodes within a directory,899 * callers are responsible for taking any locks necessary to prevent the900 * directory from changing.901 */902int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,903 struct msdos_dir_entry **de)904{905 loff_t offset = 0;906 907 *de = NULL;908 while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {909 if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME))910 return 0;911 }912 return -ENOENT;913}914EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);915 916/* See if directory is empty */917int fat_dir_empty(struct inode *dir)918{919 struct buffer_head *bh;920 struct msdos_dir_entry *de;921 loff_t cpos;922 int result = 0;923 924 bh = NULL;925 cpos = 0;926 while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {927 if (strncmp(de->name, MSDOS_DOT , MSDOS_NAME) &&928 strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {929 result = -ENOTEMPTY;930 break;931 }932 }933 brelse(bh);934 return result;935}936EXPORT_SYMBOL_GPL(fat_dir_empty);937 938/*939 * fat_subdirs counts the number of sub-directories of dir. It can be run940 * on directories being created.941 */942int fat_subdirs(struct inode *dir)943{944 struct buffer_head *bh;945 struct msdos_dir_entry *de;946 loff_t cpos;947 int count = 0;948 949 bh = NULL;950 cpos = 0;951 while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {952 if (de->attr & ATTR_DIR)953 count++;954 }955 brelse(bh);956 return count;957}958 959/*960 * Scans a directory for a given file (name points to its formatted name).961 * Returns an error code or zero.962 */963int fat_scan(struct inode *dir, const unsigned char *name,964 struct fat_slot_info *sinfo)965{966 struct super_block *sb = dir->i_sb;967 968 sinfo->slot_off = 0;969 sinfo->bh = NULL;970 while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,971 &sinfo->de) >= 0) {972 if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) {973 sinfo->slot_off -= sizeof(*sinfo->de);974 sinfo->nr_slots = 1;975 sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);976 return 0;977 }978 }979 return -ENOENT;980}981EXPORT_SYMBOL_GPL(fat_scan);982 983/*984 * Scans a directory for a given logstart.985 * Returns an error code or zero.986 */987int fat_scan_logstart(struct inode *dir, int i_logstart,988 struct fat_slot_info *sinfo)989{990 struct super_block *sb = dir->i_sb;991 992 sinfo->slot_off = 0;993 sinfo->bh = NULL;994 while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,995 &sinfo->de) >= 0) {996 if (fat_get_start(MSDOS_SB(sb), sinfo->de) == i_logstart) {997 sinfo->slot_off -= sizeof(*sinfo->de);998 sinfo->nr_slots = 1;999 sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);1000 return 0;1001 }1002 }1003 return -ENOENT;1004}1005 1006static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)1007{1008 struct super_block *sb = dir->i_sb;1009 struct buffer_head *bh;1010 struct msdos_dir_entry *de, *endp;1011 int err = 0, orig_slots;1012 1013 while (nr_slots) {1014 bh = NULL;1015 if (fat_get_entry(dir, &pos, &bh, &de) < 0) {1016 err = -EIO;1017 break;1018 }1019 1020 orig_slots = nr_slots;1021 endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize);1022 while (nr_slots && de < endp) {1023 de->name[0] = DELETED_FLAG;1024 de++;1025 nr_slots--;1026 }1027 mark_buffer_dirty_inode(bh, dir);1028 if (IS_DIRSYNC(dir))1029 err = sync_dirty_buffer(bh);1030 brelse(bh);1031 if (err)1032 break;1033 1034 /* pos is *next* de's position, so this does `- sizeof(de)' */1035 pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de);1036 }1037 1038 return err;1039}1040 1041int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)1042{1043 struct super_block *sb = dir->i_sb;1044 struct msdos_dir_entry *de;1045 struct buffer_head *bh;1046 int err = 0, nr_slots;1047 1048 /*1049 * First stage: Remove the shortname. By this, the directory1050 * entry is removed.1051 */1052 nr_slots = sinfo->nr_slots;1053 de = sinfo->de;1054 sinfo->de = NULL;1055 bh = sinfo->bh;1056 sinfo->bh = NULL;1057 while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) {1058 de->name[0] = DELETED_FLAG;1059 de--;1060 nr_slots--;1061 }1062 mark_buffer_dirty_inode(bh, dir);1063 if (IS_DIRSYNC(dir))1064 err = sync_dirty_buffer(bh);1065 brelse(bh);1066 if (err)1067 return err;1068 inode_inc_iversion(dir);1069 1070 if (nr_slots) {1071 /*1072 * Second stage: remove the remaining longname slots.1073 * (This directory entry is already removed, and so return1074 * the success)1075 */1076 err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots);1077 if (err) {1078 fat_msg(sb, KERN_WARNING,1079 "Couldn't remove the long name slots");1080 }1081 }1082 1083 fat_truncate_time(dir, NULL, S_ATIME|S_MTIME);1084 if (IS_DIRSYNC(dir))1085 (void)fat_sync_inode(dir);1086 else1087 mark_inode_dirty(dir);1088 1089 return 0;1090}1091EXPORT_SYMBOL_GPL(fat_remove_entries);1092 1093static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,1094 struct buffer_head **bhs, int nr_bhs)1095{1096 struct super_block *sb = dir->i_sb;1097 sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus;1098 int err, i, n;1099 1100 /* Zeroing the unused blocks on this cluster */1101 blknr += nr_used;1102 n = nr_used;1103 while (blknr < last_blknr) {1104 bhs[n] = sb_getblk(sb, blknr);1105 if (!bhs[n]) {1106 err = -ENOMEM;1107 goto error;1108 }1109 /* Avoid race with userspace read via bdev */1110 lock_buffer(bhs[n]);1111 memset(bhs[n]->b_data, 0, sb->s_blocksize);1112 set_buffer_uptodate(bhs[n]);1113 unlock_buffer(bhs[n]);1114 mark_buffer_dirty_inode(bhs[n], dir);1115 1116 n++;1117 blknr++;1118 if (n == nr_bhs) {1119 if (IS_DIRSYNC(dir)) {1120 err = fat_sync_bhs(bhs, n);1121 if (err)1122 goto error;1123 }1124 for (i = 0; i < n; i++)1125 brelse(bhs[i]);1126 n = 0;1127 }1128 }1129 if (IS_DIRSYNC(dir)) {1130 err = fat_sync_bhs(bhs, n);1131 if (err)1132 goto error;1133 }1134 for (i = 0; i < n; i++)1135 brelse(bhs[i]);1136 1137 return 0;1138 1139error:1140 for (i = 0; i < n; i++)1141 bforget(bhs[i]);1142 return err;1143}1144 1145int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts)1146{1147 struct super_block *sb = dir->i_sb;1148 struct msdos_sb_info *sbi = MSDOS_SB(sb);1149 struct buffer_head *bhs[MAX_BUF_PER_PAGE];1150 struct msdos_dir_entry *de;1151 sector_t blknr;1152 __le16 date, time;1153 u8 time_cs;1154 int err, cluster;1155 1156 err = fat_alloc_clusters(dir, &cluster, 1);1157 if (err)1158 goto error;1159 1160 blknr = fat_clus_to_blknr(sbi, cluster);1161 bhs[0] = sb_getblk(sb, blknr);1162 if (!bhs[0]) {1163 err = -ENOMEM;1164 goto error_free;1165 }1166 1167 fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);1168 1169 de = (struct msdos_dir_entry *)bhs[0]->b_data;1170 /* Avoid race with userspace read via bdev */1171 lock_buffer(bhs[0]);1172 /* filling the new directory slots ("." and ".." entries) */1173 memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME);1174 memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME);1175 de->attr = de[1].attr = ATTR_DIR;1176 de[0].lcase = de[1].lcase = 0;1177 de[0].time = de[1].time = time;1178 de[0].date = de[1].date = date;1179 if (sbi->options.isvfat) {1180 /* extra timestamps */1181 de[0].ctime = de[1].ctime = time;1182 de[0].ctime_cs = de[1].ctime_cs = time_cs;1183 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date;1184 } else {1185 de[0].ctime = de[1].ctime = 0;1186 de[0].ctime_cs = de[1].ctime_cs = 0;1187 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;1188 }1189 fat_set_start(&de[0], cluster);1190 fat_set_start(&de[1], MSDOS_I(dir)->i_logstart);1191 de[0].size = de[1].size = 0;1192 memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));1193 set_buffer_uptodate(bhs[0]);1194 unlock_buffer(bhs[0]);1195 mark_buffer_dirty_inode(bhs[0], dir);1196 1197 err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);1198 if (err)1199 goto error_free;1200 1201 return cluster;1202 1203error_free:1204 fat_free_clusters(dir, cluster);1205error:1206 return err;1207}1208EXPORT_SYMBOL_GPL(fat_alloc_new_dir);1209 1210static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,1211 int *nr_cluster, struct msdos_dir_entry **de,1212 struct buffer_head **bh, loff_t *i_pos)1213{1214 struct super_block *sb = dir->i_sb;1215 struct msdos_sb_info *sbi = MSDOS_SB(sb);1216 struct buffer_head *bhs[MAX_BUF_PER_PAGE];1217 sector_t blknr, start_blknr, last_blknr;1218 unsigned long size, copy;1219 int err, i, n, offset, cluster[2];1220 1221 /*1222 * The minimum cluster size is 512bytes, and maximum entry1223 * size is 32*slots (672bytes). So, iff the cluster size is1224 * 512bytes, we may need two clusters.1225 */1226 size = nr_slots * sizeof(struct msdos_dir_entry);1227 *nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits;1228 BUG_ON(*nr_cluster > 2);1229 1230 err = fat_alloc_clusters(dir, cluster, *nr_cluster);1231 if (err)1232 goto error;1233 1234 /*1235 * First stage: Fill the directory entry. NOTE: This cluster1236 * is not referenced from any inode yet, so updates order is1237 * not important.1238 */1239 i = n = copy = 0;1240 do {1241 start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]);1242 last_blknr = start_blknr + sbi->sec_per_clus;1243 while (blknr < last_blknr) {1244 bhs[n] = sb_getblk(sb, blknr);1245 if (!bhs[n]) {1246 err = -ENOMEM;1247 goto error_nomem;1248 }1249 1250 /* fill the directory entry */1251 copy = min(size, sb->s_blocksize);1252 /* Avoid race with userspace read via bdev */1253 lock_buffer(bhs[n]);1254 memcpy(bhs[n]->b_data, slots, copy);1255 set_buffer_uptodate(bhs[n]);1256 unlock_buffer(bhs[n]);1257 mark_buffer_dirty_inode(bhs[n], dir);1258 slots += copy;1259 size -= copy;1260 if (!size)1261 break;1262 n++;1263 blknr++;1264 }1265 } while (++i < *nr_cluster);1266 1267 memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy);1268 offset = copy - sizeof(struct msdos_dir_entry);1269 get_bh(bhs[n]);1270 *bh = bhs[n];1271 *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);1272 *i_pos = fat_make_i_pos(sb, *bh, *de);1273 1274 /* Second stage: clear the rest of cluster, and write outs */1275 err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE);1276 if (err)1277 goto error_free;1278 1279 return cluster[0];1280 1281error_free:1282 brelse(*bh);1283 *bh = NULL;1284 n = 0;1285error_nomem:1286 for (i = 0; i < n; i++)1287 bforget(bhs[i]);1288 fat_free_clusters(dir, cluster[0]);1289error:1290 return err;1291}1292 1293int fat_add_entries(struct inode *dir, void *slots, int nr_slots,1294 struct fat_slot_info *sinfo)1295{1296 struct super_block *sb = dir->i_sb;1297 struct msdos_sb_info *sbi = MSDOS_SB(sb);1298 struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */1299 struct msdos_dir_entry *de;1300 int err, free_slots, i, nr_bhs;1301 loff_t pos, i_pos;1302 1303 sinfo->nr_slots = nr_slots;1304 1305 /* First stage: search free directory entries */1306 free_slots = nr_bhs = 0;1307 bh = prev = NULL;1308 pos = 0;1309 err = -ENOSPC;1310 while (fat_get_entry(dir, &pos, &bh, &de) > -1) {1311 /* check the maximum size of directory */1312 if (pos >= FAT_MAX_DIR_SIZE)1313 goto error;1314 1315 if (IS_FREE(de->name)) {1316 if (prev != bh) {1317 get_bh(bh);1318 bhs[nr_bhs] = prev = bh;1319 nr_bhs++;1320 }1321 free_slots++;1322 if (free_slots == nr_slots)1323 goto found;1324 } else {1325 for (i = 0; i < nr_bhs; i++)1326 brelse(bhs[i]);1327 prev = NULL;1328 free_slots = nr_bhs = 0;1329 }1330 }1331 if (dir->i_ino == MSDOS_ROOT_INO) {1332 if (!is_fat32(sbi))1333 goto error;1334 } else if (MSDOS_I(dir)->i_start == 0) {1335 fat_msg(sb, KERN_ERR, "Corrupted directory (i_pos %lld)",1336 MSDOS_I(dir)->i_pos);1337 err = -EIO;1338 goto error;1339 }1340 1341found:1342 err = 0;1343 pos -= free_slots * sizeof(*de);1344 nr_slots -= free_slots;1345 if (free_slots) {1346 /*1347 * Second stage: filling the free entries with new entries.1348 * NOTE: If this slots has shortname, first, we write1349 * the long name slots, then write the short name.1350 */1351 int size = free_slots * sizeof(*de);1352 int offset = pos & (sb->s_blocksize - 1);1353 int long_bhs = nr_bhs - (nr_slots == 0);1354 1355 /* Fill the long name slots. */1356 for (i = 0; i < long_bhs; i++) {1357 int copy = min_t(int, sb->s_blocksize - offset, size);1358 memcpy(bhs[i]->b_data + offset, slots, copy);1359 mark_buffer_dirty_inode(bhs[i], dir);1360 offset = 0;1361 slots += copy;1362 size -= copy;1363 }1364 if (long_bhs && IS_DIRSYNC(dir))1365 err = fat_sync_bhs(bhs, long_bhs);1366 if (!err && i < nr_bhs) {1367 /* Fill the short name slot. */1368 int copy = min_t(int, sb->s_blocksize - offset, size);1369 memcpy(bhs[i]->b_data + offset, slots, copy);1370 mark_buffer_dirty_inode(bhs[i], dir);1371 if (IS_DIRSYNC(dir))1372 err = sync_dirty_buffer(bhs[i]);1373 }1374 for (i = 0; i < nr_bhs; i++)1375 brelse(bhs[i]);1376 if (err)1377 goto error_remove;1378 }1379 1380 if (nr_slots) {1381 int cluster, nr_cluster;1382 1383 /*1384 * Third stage: allocate the cluster for new entries.1385 * And initialize the cluster with new entries, then1386 * add the cluster to dir.1387 */1388 cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster,1389 &de, &bh, &i_pos);1390 if (cluster < 0) {1391 err = cluster;1392 goto error_remove;1393 }1394 err = fat_chain_add(dir, cluster, nr_cluster);1395 if (err) {1396 fat_free_clusters(dir, cluster);1397 goto error_remove;1398 }1399 if (dir->i_size & (sbi->cluster_size - 1)) {1400 fat_fs_error(sb, "Odd directory size");1401 dir->i_size = (dir->i_size + sbi->cluster_size - 1)1402 & ~((loff_t)sbi->cluster_size - 1);1403 }1404 dir->i_size += nr_cluster << sbi->cluster_bits;1405 MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits;1406 }1407 sinfo->slot_off = pos;1408 sinfo->de = de;1409 sinfo->bh = bh;1410 sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);1411 1412 return 0;1413 1414error:1415 brelse(bh);1416 for (i = 0; i < nr_bhs; i++)1417 brelse(bhs[i]);1418 return err;1419 1420error_remove:1421 brelse(bh);1422 if (free_slots)1423 __fat_remove_entries(dir, pos, free_slots);1424 return err;1425}1426EXPORT_SYMBOL_GPL(fat_add_entries);1427