4 * directory handling functions for fat-based filesystems
6 * Written 1992,1993 by Werner Almesberger
8 * Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
10 * VFAT extensions by Gordon Chaffee <chaffee@plateau.cs.berkeley.edu>
11 * Merged with msdos fs by Henrik Storner <storner@osiris.ping.dk>
12 * Rewritten for constant inumbers. Plugged buffer overrun in readdir(). AV
13 * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
16 #include <linux/slab.h>
17 #include <linux/time.h>
18 #include <linux/msdos_fs.h>
19 #include <linux/dirent.h>
20 #include <linux/smp_lock.h>
21 #include <linux/buffer_head.h>
23 #include <asm/uaccess.h>
25 struct file_operations fat_dir_operations = {
26 .read = generic_read_dir,
27 .readdir = fat_readdir,
28 .ioctl = fat_dir_ioctl,
33 * Convert Unicode 16 to UTF8, translated Unicode, or ASCII.
34 * If uni_xlate is enabled and we can't get a 1:1 conversion, use a
35 * colon as an escape character since it is normally invalid on the vfat
36 * filesystem. The following four characters are the hexadecimal digits
37 * of Unicode value. This lets us do a full dump and restore of Unicode
38 * filenames. We could get into some trouble with long Unicode names,
39 * but ignore that right now.
40 * Ahem... Stack smashing in ring 0 isn't fun. Fixed.
43 uni16_to_x8(unsigned char *ascii, wchar_t *uni, int uni_xlate,
44 struct nls_table *nls)
47 unsigned char *op, nc;
56 if ( (charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE)) > 0) {
61 for (k = 4; k > 0; k--) {
63 op[k] = nc > 9 ? nc + ('a' - 10)
72 /* We have some slack there, so it's OK */
83 static void dump_de(struct msdos_dir_entry *de)
86 unsigned char *p = (unsigned char *) de;
89 for (i = 0; i < 32; i++, p++) {
97 fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
101 charlen = t->char2uni(c, clen, uni);
103 *uni = 0x003f; /* a question mark */
110 fat_short2lower_uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
115 charlen = t->char2uni(c, clen, &wc);
117 *uni = 0x003f; /* a question mark */
119 } else if (charlen <= 1) {
120 unsigned char nc = t->charset2lower[*c];
125 if ( (charlen = t->char2uni(&nc, 1, uni)) < 0) {
126 *uni = 0x003f; /* a question mark */
136 fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,
137 wchar_t *uni_buf, unsigned short opt, int lower)
141 if (opt & VFAT_SFN_DISPLAY_LOWER)
142 len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
143 else if (opt & VFAT_SFN_DISPLAY_WIN95)
144 len = fat_short2uni(nls, buf, buf_size, uni_buf);
145 else if (opt & VFAT_SFN_DISPLAY_WINNT) {
147 len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
149 len = fat_short2uni(nls, buf, buf_size, uni_buf);
151 len = fat_short2uni(nls, buf, buf_size, uni_buf);
157 * Return values: negative -> error, 0 -> not found, positive -> found,
158 * value is the total amount of slots, including the shortname entry.
160 int fat_search_long(struct inode *inode, const unsigned char *name,
161 int name_len, int anycase, loff_t *spos, loff_t *lpos)
163 struct super_block *sb = inode->i_sb;
164 struct buffer_head *bh = NULL;
165 struct msdos_dir_entry *de;
166 struct nls_table *nls_io = MSDOS_SB(sb)->nls_io;
167 struct nls_table *nls_disk = MSDOS_SB(sb)->nls_disk;
168 wchar_t bufuname[14];
169 unsigned char xlate_len, long_slots;
170 wchar_t *unicode = NULL;
171 unsigned char work[8], bufname[260]; /* 256 + 4 */
172 int uni_xlate = MSDOS_SB(sb)->options.unicode_xlate;
173 int utf8 = MSDOS_SB(sb)->options.utf8;
174 unsigned short opt_shortname = MSDOS_SB(sb)->options.shortname;
175 int chl, i, j, last_u, res = 0;
176 loff_t i_pos, cpos = 0;
179 if (fat_get_entry(inode,&cpos,&bh,&de,&i_pos) == -1)
183 if (de->name[0] == DELETED_FLAG)
185 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
187 if (de->attr != ATTR_EXT && IS_FREE(de->name))
189 if (de->attr == ATTR_EXT) {
190 struct msdos_dir_slot *ds;
195 unsigned char alias_checksum;
198 unicode = (wchar_t *)
199 __get_free_page(GFP_KERNEL);
207 ds = (struct msdos_dir_slot *) de;
212 if (slots > 20 || !slots) /* ceil(256 * 2 / 26) */
215 alias_checksum = ds->alias_checksum;
223 fat16_towchar(unicode + offset, ds->name0_4, 5);
224 fat16_towchar(unicode + offset + 5, ds->name5_10, 6);
225 fat16_towchar(unicode + offset + 11, ds->name11_12, 2);
228 unicode[offset + 13] = 0;
230 if (fat_get_entry(inode,&cpos,&bh,&de,&i_pos)<0)
234 ds = (struct msdos_dir_slot *) de;
235 if (ds->attr != ATTR_EXT)
237 if ((ds->id & ~0x40) != slot)
239 if (ds->alias_checksum != alias_checksum)
242 if (de->name[0] == DELETED_FLAG)
244 if (de->attr == ATTR_EXT)
246 if (IS_FREE(de->name) || (de->attr & ATTR_VOLUME))
248 for (sum = 0, i = 0; i < 11; i++)
249 sum = (((sum&1)<<7)|((sum&0xfe)>>1)) + de->name[i];
250 if (sum != alias_checksum)
254 memcpy(work, de->name, sizeof(de->name));
255 /* see namei.c, msdos_format_name */
258 for (i = 0, j = 0, last_u = 0; i < 8;) {
260 chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
261 &bufuname[j++], opt_shortname,
262 de->lcase & CASE_LOWER_BASE);
272 fat_short2uni(nls_disk, ".", 1, &bufuname[j++]);
273 for (i = 0; i < 3;) {
274 if (!de->ext[i]) break;
275 chl = fat_shortname2uni(nls_disk, &de->ext[i], 3 - i,
276 &bufuname[j++], opt_shortname,
277 de->lcase & CASE_LOWER_EXT);
279 if (de->ext[i] != ' ')
289 bufuname[last_u] = 0x0000;
291 ?utf8_wcstombs(bufname, bufuname, sizeof(bufname))
292 :uni16_to_x8(bufname, bufuname, uni_xlate, nls_io);
293 if (xlate_len == name_len)
294 if ((!anycase && !memcmp(name, bufname, xlate_len)) ||
295 (anycase && !nls_strnicmp(nls_io, name, bufname,
301 ?utf8_wcstombs(bufname, unicode, sizeof(bufname))
302 :uni16_to_x8(bufname, unicode, uni_xlate, nls_io);
303 if (xlate_len != name_len)
305 if ((!anycase && !memcmp(name, bufname, xlate_len)) ||
306 (anycase && !nls_strnicmp(nls_io, name, bufname,
313 res = long_slots + 1;
314 *spos = cpos - sizeof(struct msdos_dir_entry);
315 *lpos = cpos - res*sizeof(struct msdos_dir_entry);
319 free_page((unsigned long) unicode);
324 static int fat_readdirx(struct inode *inode, struct file *filp, void *dirent,
325 filldir_t filldir, int shortnames, int both)
327 struct super_block *sb = inode->i_sb;
328 struct buffer_head *bh;
329 struct msdos_dir_entry *de;
330 struct nls_table *nls_io = MSDOS_SB(sb)->nls_io;
331 struct nls_table *nls_disk = MSDOS_SB(sb)->nls_disk;
332 wchar_t bufuname[14];
333 unsigned char long_slots;
334 wchar_t *unicode = NULL;
335 unsigned char c, work[8], bufname[56], *ptname = bufname;
336 unsigned long lpos, dummy, *furrfu = &lpos;
337 int uni_xlate = MSDOS_SB(sb)->options.unicode_xlate;
338 int isvfat = MSDOS_SB(sb)->options.isvfat;
339 int utf8 = MSDOS_SB(sb)->options.utf8;
340 int nocase = MSDOS_SB(sb)->options.nocase;
341 unsigned short opt_shortname = MSDOS_SB(sb)->options.shortname;
343 int chi, chl, i, i2, j, last, last_u, dotoffset = 0;
350 /* Fake . and .. for the root directory. */
351 if (inode->i_ino == MSDOS_ROOT_INO) {
353 if (filldir(dirent, "..", cpos+1, cpos, MSDOS_ROOT_INO, DT_DIR) < 0)
364 if (cpos & (sizeof(struct msdos_dir_entry)-1)) {
372 if (fat_get_entry(inode,&cpos,&bh,&de,&i_pos) == -1)
374 /* Check for long filename entry */
376 if (de->name[0] == DELETED_FLAG)
378 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
380 if (de->attr != ATTR_EXT && IS_FREE(de->name))
383 if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))
387 if (isvfat && de->attr == ATTR_EXT) {
388 struct msdos_dir_slot *ds;
393 unsigned char alias_checksum;
396 unicode = (wchar_t *)
397 __get_free_page(GFP_KERNEL);
407 ds = (struct msdos_dir_slot *) de;
412 if (slots > 20 || !slots) /* ceil(256 * 2 / 26) */
415 alias_checksum = ds->alias_checksum;
423 fat16_towchar(unicode + offset, ds->name0_4, 5);
424 fat16_towchar(unicode + offset + 5, ds->name5_10, 6);
425 fat16_towchar(unicode + offset + 11, ds->name11_12, 2);
428 unicode[offset + 13] = 0;
430 if (fat_get_entry(inode,&cpos,&bh,&de,&i_pos) == -1)
434 ds = (struct msdos_dir_slot *) de;
435 if (ds->attr != ATTR_EXT)
436 goto RecEnd; /* XXX */
437 if ((ds->id & ~0x40) != slot)
439 if (ds->alias_checksum != alias_checksum)
442 if (de->name[0] == DELETED_FLAG)
444 if (de->attr == ATTR_EXT)
446 if (IS_FREE(de->name) || (de->attr & ATTR_VOLUME))
448 for (sum = 0, i = 0; i < 11; i++)
449 sum = (((sum&1)<<7)|((sum&0xfe)>>1)) + de->name[i];
450 if (sum != alias_checksum)
454 if ((de->attr & ATTR_HIDDEN) && MSDOS_SB(sb)->options.dotsOK) {
459 memcpy(work, de->name, sizeof(de->name));
460 /* see namei.c, msdos_format_name */
463 for (i = 0, j = 0, last = 0, last_u = 0; i < 8;) {
464 if (!(c = work[i])) break;
465 chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
466 &bufuname[j++], opt_shortname,
467 de->lcase & CASE_LOWER_BASE);
469 ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
476 for (chi = 0; chi < chl && i < 8; chi++) {
484 fat_short2uni(nls_disk, ".", 1, &bufuname[j++]);
486 for (i2 = 0; i2 < 3;) {
487 if (!(c = de->ext[i2])) break;
488 chl = fat_shortname2uni(nls_disk, &de->ext[i2], 3 - i2,
489 &bufuname[j++], opt_shortname,
490 de->lcase & CASE_LOWER_EXT);
493 ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
500 for (chi = 0; chi < chl && i2 < 3; chi++) {
501 ptname[i++] = de->ext[i2++];
509 i = last + dotoffset;
512 lpos = cpos - (long_slots+1)*sizeof(struct msdos_dir_entry);
513 if (!memcmp(de->name,MSDOS_DOT,11))
515 else if (!memcmp(de->name,MSDOS_DOTDOT,11)) {
516 inum = parent_ino(filp->f_dentry);
518 struct inode *tmp = fat_iget(sb, i_pos);
523 inum = iunique(sb, MSDOS_ROOT_INO);
527 bufuname[j] = 0x0000;
528 i = utf8 ? utf8_wcstombs(bufname, bufuname, sizeof(bufname))
529 : uni16_to_x8(bufname, bufuname, uni_xlate, nls_io);
532 if (!long_slots||shortnames) {
535 if (filldir(dirent, bufname, i, *furrfu, inum,
536 (de->attr & ATTR_DIR) ? DT_DIR : DT_REG) < 0)
539 unsigned char longname[275];
541 ? utf8_wcstombs(longname, unicode, sizeof(longname))
542 : uni16_to_x8(longname, unicode, uni_xlate,
545 memcpy(&longname[long_len+1], bufname, i);
548 if (filldir(dirent, longname, long_len, *furrfu, inum,
549 (de->attr & ATTR_DIR) ? DT_DIR : DT_REG) < 0)
563 free_page((unsigned long) unicode);
570 int fat_readdir(struct file *filp, void *dirent, filldir_t filldir)
572 struct inode *inode = filp->f_dentry->d_inode;
573 return fat_readdirx(inode, filp, dirent, filldir, 0, 0);
576 struct fat_ioctl_filldir_callback {
577 struct dirent __user *dirent;
581 static int fat_ioctl_filldir(void *__buf, const char * name, int name_len,
582 loff_t offset, ino_t ino, unsigned int d_type)
584 struct fat_ioctl_filldir_callback *buf = __buf;
585 struct dirent __user *d1 = buf->dirent;
586 struct dirent __user *d2 = d1 + 1;
594 if ((name_len == 1 && name[0] == '.') ||
595 (name_len == 2 && name[0] == '.' && name[1] == '.')) {
602 if (len != name_len) {
603 slen = name_len - len;
604 if (copy_to_user(d2->d_name, name, len) ||
605 put_user(0, d2->d_name + len) ||
606 put_user(len, &d2->d_reclen) ||
607 put_user(ino, &d2->d_ino) ||
608 put_user(offset, &d2->d_off) ||
609 copy_to_user(d1->d_name, name+len+1, slen) ||
610 put_user(0, d1->d_name+slen) ||
611 put_user(slen, &d1->d_reclen))
614 if (put_user(0, d2->d_name) ||
615 put_user(0, &d2->d_reclen) ||
616 copy_to_user(d1->d_name, name, len) ||
617 put_user(0, d1->d_name+len) ||
618 put_user(len, &d1->d_reclen))
623 buf->result = -EFAULT;
627 int fat_dir_ioctl(struct inode * inode, struct file * filp,
628 unsigned int cmd, unsigned long arg)
630 struct fat_ioctl_filldir_callback buf;
631 struct dirent __user *d1;
632 int ret, shortname, both;
635 case VFAT_IOCTL_READDIR_SHORT:
639 case VFAT_IOCTL_READDIR_BOTH:
647 d1 = (struct dirent __user *)arg;
648 if (!access_ok(VERIFY_WRITE, d1, sizeof(struct dirent[2])))
651 * Yes, we don't need this put_user() absolutely. However old
652 * code didn't return the right value. So, app use this value,
653 * in order to check whether it is EOF.
655 if (put_user(0, &d1->d_reclen))
662 if (!IS_DEADDIR(inode)) {
663 ret = fat_readdirx(inode, filp, &buf, fat_ioctl_filldir,
672 /* This assumes that size of cluster is above the 32*slots */
674 int fat_add_entries(struct inode *dir,int slots, struct buffer_head **bh,
675 struct msdos_dir_entry **de, loff_t *i_pos)
677 struct super_block *sb = dir->i_sb;
680 struct buffer_head *new_bh;
685 while (fat_get_entry(dir, &curr, bh, de, i_pos) > -1) {
686 /* check the maximum size of directory */
687 if (curr >= FAT_MAX_DIR_SIZE) {
692 if (IS_FREE((*de)->name)) {
700 if ((dir->i_ino == MSDOS_ROOT_INO) && (MSDOS_SB(sb)->fat_bits != 32))
702 new_bh = fat_extend_dir(dir);
704 return PTR_ERR(new_bh);
707 fat_get_entry(dir, &curr, bh, de, i_pos);
708 } while (++row < slots);
713 int fat_new_dir(struct inode *dir, struct inode *parent, int is_vfat)
715 struct buffer_head *bh;
716 struct msdos_dir_entry *de;
719 bh = fat_extend_dir(dir);
723 /* zeroed out, so... */
724 fat_date_unix2dos(dir->i_mtime.tv_sec,&time,&date);
725 de = (struct msdos_dir_entry*)&bh->b_data[0];
726 memcpy(de[0].name,MSDOS_DOT,MSDOS_NAME);
727 memcpy(de[1].name,MSDOS_DOTDOT,MSDOS_NAME);
728 de[0].attr = de[1].attr = ATTR_DIR;
729 de[0].time = de[1].time = time;
730 de[0].date = de[1].date = date;
731 if (is_vfat) { /* extra timestamps */
732 de[0].ctime = de[1].ctime = time;
733 de[0].adate = de[0].cdate =
734 de[1].adate = de[1].cdate = date;
736 de[0].start = CT_LE_W(MSDOS_I(dir)->i_logstart);
737 de[0].starthi = CT_LE_W(MSDOS_I(dir)->i_logstart>>16);
738 de[1].start = CT_LE_W(MSDOS_I(parent)->i_logstart);
739 de[1].starthi = CT_LE_W(MSDOS_I(parent)->i_logstart>>16);
740 mark_buffer_dirty(bh);
742 dir->i_atime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
743 mark_inode_dirty(dir);
748 static int fat_get_short_entry(struct inode *dir, loff_t *pos,
749 struct buffer_head **bh,
750 struct msdos_dir_entry **de, loff_t *i_pos)
752 while (fat_get_entry(dir, pos, bh, de, i_pos) >= 0) {
753 /* free entry or long name entry or volume label */
754 if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
760 /* See if directory is empty */
761 int fat_dir_empty(struct inode *dir)
763 struct buffer_head *bh;
764 struct msdos_dir_entry *de;
770 while (fat_get_short_entry(dir, &cpos, &bh, &de, &i_pos) >= 0) {
771 if (strncmp(de->name, MSDOS_DOT , MSDOS_NAME) &&
772 strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
782 * fat_subdirs counts the number of sub-directories of dir. It can be run
783 * on directories being created.
785 int fat_subdirs(struct inode *dir)
787 struct buffer_head *bh;
788 struct msdos_dir_entry *de;
794 while (fat_get_short_entry(dir, &cpos, &bh, &de, &i_pos) >= 0) {
795 if (de->attr & ATTR_DIR)
803 * Scans a directory for a given file (name points to its formatted name).
804 * Returns an error code or zero.
806 int fat_scan(struct inode *dir, const unsigned char *name,
807 struct buffer_head **bh, struct msdos_dir_entry **de,
814 while (fat_get_short_entry(dir, &cpos, bh, de, i_pos) >= 0) {
815 if (!strncmp((*de)->name, name, MSDOS_NAME))