diff options
Diffstat (limited to 'fs/fat/dir.c')
| -rw-r--r-- | fs/fat/dir.c | 1414 |
1 files changed, 1414 insertions, 0 deletions
diff --git a/fs/fat/dir.c b/fs/fat/dir.c new file mode 100644 index 0000000000..00235b8a18 --- /dev/null +++ b/fs/fat/dir.c @@ -0,0 +1,1414 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/fs/fat/dir.c + * + * directory handling functions for fat-based filesystems + * + * Written 1992,1993 by Werner Almesberger + * + * Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu> + * + * VFAT extensions by Gordon Chaffee <chaffee@plateau.cs.berkeley.edu> + * Merged with msdos fs by Henrik Storner <storner@osiris.ping.dk> + * Rewritten for constant inumbers. Plugged buffer overrun in readdir(). AV + * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de> + */ + +#include <linux/slab.h> +#include <linux/compat.h> +#include <linux/uaccess.h> +#include <linux/iversion.h> +#include "fat.h" + +/* + * Maximum buffer size of short name. + * [(MSDOS_NAME + '.') * max one char + nul] + * For msdos style, ['.' (hidden) + MSDOS_NAME + '.' + nul] + */ +#define FAT_MAX_SHORT_SIZE ((MSDOS_NAME + 1) * NLS_MAX_CHARSET_SIZE + 1) +/* + * Maximum buffer size of unicode chars from slots. + * [(max longname slots * 13 (size in a slot) + nul) * sizeof(wchar_t)] + */ +#define FAT_MAX_UNI_CHARS ((MSDOS_SLOTS - 1) * 13 + 1) +#define FAT_MAX_UNI_SIZE (FAT_MAX_UNI_CHARS * sizeof(wchar_t)) + +static inline unsigned char fat_tolower(unsigned char c) +{ + return ((c >= 'A') && (c <= 'Z')) ? c+32 : c; +} + +static inline loff_t fat_make_i_pos(struct super_block *sb, + struct buffer_head *bh, + struct msdos_dir_entry *de) +{ + return ((loff_t)bh->b_blocknr << MSDOS_SB(sb)->dir_per_block_bits) + | (de - (struct msdos_dir_entry *)bh->b_data); +} + +static inline void fat_dir_readahead(struct inode *dir, sector_t iblock, + sector_t phys) +{ + struct super_block *sb = dir->i_sb; + struct msdos_sb_info *sbi = MSDOS_SB(sb); + struct buffer_head *bh; + int sec; + + /* This is not a first sector of cluster, or sec_per_clus == 1 */ + if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1) + return; + /* root dir of FAT12/FAT16 */ + if (!is_fat32(sbi) && (dir->i_ino == MSDOS_ROOT_INO)) + return; + + bh = sb_find_get_block(sb, phys); + if (bh == NULL || !buffer_uptodate(bh)) { + for (sec = 0; sec < sbi->sec_per_clus; sec++) + sb_breadahead(sb, phys + sec); + } + brelse(bh); +} + +/* Returns the inode number of the directory entry at offset pos. If bh is + non-NULL, it is brelse'd before. Pos is incremented. The buffer header is + returned in bh. + AV. Most often we do it item-by-item. Makes sense to optimize. + AV. OK, there we go: if both bh and de are non-NULL we assume that we just + AV. want the next entry (took one explicit de=NULL in vfat/namei.c). + AV. It's done in fat_get_entry() (inlined), here the slow case lives. + AV. Additionally, when we return -1 (i.e. reached the end of directory) + AV. we make bh NULL. + */ +static int fat__get_entry(struct inode *dir, loff_t *pos, + struct buffer_head **bh, struct msdos_dir_entry **de) +{ + struct super_block *sb = dir->i_sb; + sector_t phys, iblock; + unsigned long mapped_blocks; + int err, offset; + +next: + brelse(*bh); + *bh = NULL; + iblock = *pos >> sb->s_blocksize_bits; + err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0, false); + if (err || !phys) + return -1; /* beyond EOF or error */ + + fat_dir_readahead(dir, iblock, phys); + + *bh = sb_bread(sb, phys); + if (*bh == NULL) { + fat_msg_ratelimit(sb, KERN_ERR, + "Directory bread(block %llu) failed", (llu)phys); + /* skip this block */ + *pos = (iblock + 1) << sb->s_blocksize_bits; + goto next; + } + + offset = *pos & (sb->s_blocksize - 1); + *pos += sizeof(struct msdos_dir_entry); + *de = (struct msdos_dir_entry *)((*bh)->b_data + offset); + + return 0; +} + +static inline int fat_get_entry(struct inode *dir, loff_t *pos, + struct buffer_head **bh, + struct msdos_dir_entry **de) +{ + /* Fast stuff first */ + if (*bh && *de && + (*de - (struct msdos_dir_entry *)(*bh)->b_data) < + MSDOS_SB(dir->i_sb)->dir_per_block - 1) { + *pos += sizeof(struct msdos_dir_entry); + (*de)++; + return 0; + } + return fat__get_entry(dir, pos, bh, de); +} + +/* + * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII. + * If uni_xlate is enabled and we can't get a 1:1 conversion, use a + * colon as an escape character since it is normally invalid on the vfat + * filesystem. The following four characters are the hexadecimal digits + * of Unicode value. This lets us do a full dump and restore of Unicode + * filenames. We could get into some trouble with long Unicode names, + * but ignore that right now. + * Ahem... Stack smashing in ring 0 isn't fun. Fixed. + */ +static int uni16_to_x8(struct super_block *sb, unsigned char *ascii, + const wchar_t *uni, int len, struct nls_table *nls) +{ + int uni_xlate = MSDOS_SB(sb)->options.unicode_xlate; + const wchar_t *ip; + wchar_t ec; + unsigned char *op; + int charlen; + + ip = uni; + op = ascii; + + while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) { + ec = *ip++; + charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE); + if (charlen > 0) { + op += charlen; + len -= charlen; + } else { + if (uni_xlate == 1) { + *op++ = ':'; + op = hex_byte_pack(op, ec >> 8); + op = hex_byte_pack(op, ec); + len -= 5; + } else { + *op++ = '?'; + len--; + } + } + } + + if (unlikely(*ip)) { + fat_msg(sb, KERN_WARNING, + "filename was truncated while converting."); + } + + *op = 0; + return op - ascii; +} + +static inline int fat_uni_to_x8(struct super_block *sb, const wchar_t *uni, + unsigned char *buf, int size) +{ + struct msdos_sb_info *sbi = MSDOS_SB(sb); + if (sbi->options.utf8) + return utf16s_to_utf8s(uni, FAT_MAX_UNI_CHARS, + UTF16_HOST_ENDIAN, buf, size); + else + return uni16_to_x8(sb, buf, uni, size, sbi->nls_io); +} + +static inline int +fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni) +{ + int charlen; + + charlen = t->char2uni(c, clen, uni); + if (charlen < 0) { + *uni = 0x003f; /* a question mark */ + charlen = 1; + } + return charlen; +} + +static inline int +fat_short2lower_uni(struct nls_table *t, unsigned char *c, + int clen, wchar_t *uni) +{ + int charlen; + wchar_t wc; + + charlen = t->char2uni(c, clen, &wc); + if (charlen < 0) { + *uni = 0x003f; /* a question mark */ + charlen = 1; + } else if (charlen <= 1) { + unsigned char nc = t->charset2lower[*c]; + + if (!nc) + nc = *c; + + charlen = t->char2uni(&nc, 1, uni); + if (charlen < 0) { + *uni = 0x003f; /* a question mark */ + charlen = 1; + } + } else + *uni = wc; + + return charlen; +} + +static inline int +fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size, + wchar_t *uni_buf, unsigned short opt, int lower) +{ + int len = 0; + + if (opt & VFAT_SFN_DISPLAY_LOWER) + len = fat_short2lower_uni(nls, buf, buf_size, uni_buf); + else if (opt & VFAT_SFN_DISPLAY_WIN95) + len = fat_short2uni(nls, buf, buf_size, uni_buf); + else if (opt & VFAT_SFN_DISPLAY_WINNT) { + if (lower) + len = fat_short2lower_uni(nls, buf, buf_size, uni_buf); + else + len = fat_short2uni(nls, buf, buf_size, uni_buf); + } else + len = fat_short2uni(nls, buf, buf_size, uni_buf); + + return len; +} + +static inline int fat_name_match(struct msdos_sb_info *sbi, + const unsigned char *a, int a_len, + const unsigned char *b, int b_len) +{ + if (a_len != b_len) + return 0; + + if (sbi->options.name_check != 's') + return !nls_strnicmp(sbi->nls_io, a, b, a_len); + else + return !memcmp(a, b, a_len); +} + +enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, }; + +/** + * fat_parse_long - Parse extended directory entry. + * + * This function returns zero on success, negative value on error, or one of + * the following: + * + * %PARSE_INVALID - Directory entry is invalid. + * %PARSE_NOT_LONGNAME - Directory entry does not contain longname. + * %PARSE_EOF - Directory has no more entries. + */ +static int fat_parse_long(struct inode *dir, loff_t *pos, + struct buffer_head **bh, struct msdos_dir_entry **de, + wchar_t **unicode, unsigned char *nr_slots) +{ + struct msdos_dir_slot *ds; + unsigned char id, slot, slots, alias_checksum; + + if (!*unicode) { + *unicode = __getname(); + if (!*unicode) { + brelse(*bh); + return -ENOMEM; + } + } +parse_long: + ds = (struct msdos_dir_slot *)*de; + id = ds->id; + if (!(id & 0x40)) + return PARSE_INVALID; + slots = id & ~0x40; + if (slots > 20 || !slots) /* ceil(256 * 2 / 26) */ + return PARSE_INVALID; + *nr_slots = slots; + alias_checksum = ds->alias_checksum; + + slot = slots; + while (1) { + int offset; + + slot--; + offset = slot * 13; + fat16_towchar(*unicode + offset, ds->name0_4, 5); + fat16_towchar(*unicode + offset + 5, ds->name5_10, 6); + fat16_towchar(*unicode + offset + 11, ds->name11_12, 2); + + if (ds->id & 0x40) + (*unicode)[offset + 13] = 0; + if (fat_get_entry(dir, pos, bh, de) < 0) + return PARSE_EOF; + if (slot == 0) + break; + ds = (struct msdos_dir_slot *)*de; + if (ds->attr != ATTR_EXT) + return PARSE_NOT_LONGNAME; + if ((ds->id & ~0x40) != slot) + goto parse_long; + if (ds->alias_checksum != alias_checksum) + goto parse_long; + } + if ((*de)->name[0] == DELETED_FLAG) + return PARSE_INVALID; + if ((*de)->attr == ATTR_EXT) + goto parse_long; + if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME)) + return PARSE_INVALID; + if (fat_checksum((*de)->name) != alias_checksum) + *nr_slots = 0; + + return 0; +} + +/** + * fat_parse_short - Parse MS-DOS (short) directory entry. + * @sb: superblock + * @de: directory entry to parse + * @name: FAT_MAX_SHORT_SIZE array in which to place extracted name + * @dot_hidden: Nonzero == prepend '.' to names with ATTR_HIDDEN + * + * Returns the number of characters extracted into 'name'. + */ +static int fat_parse_short(struct super_block *sb, + const struct msdos_dir_entry *de, + unsigned char *name, int dot_hidden) +{ + const struct msdos_sb_info *sbi = MSDOS_SB(sb); + int isvfat = sbi->options.isvfat; + int nocase = sbi->options.nocase; + unsigned short opt_shortname = sbi->options.shortname; + struct nls_table *nls_disk = sbi->nls_disk; + wchar_t uni_name[14]; + unsigned char c, work[MSDOS_NAME]; + unsigned char *ptname = name; + int chi, chl, i, j, k; + int dotoffset = 0; + int name_len = 0, uni_len = 0; + + if (!isvfat && dot_hidden && (de->attr & ATTR_HIDDEN)) { + *ptname++ = '.'; + dotoffset = 1; + } + + memcpy(work, de->name, sizeof(work)); + /* For an explanation of the special treatment of 0x05 in + * filenames, see msdos_format_name in namei_msdos.c + */ + if (work[0] == 0x05) + work[0] = 0xE5; + + /* Filename */ + for (i = 0, j = 0; i < 8;) { + c = work[i]; + if (!c) + break; + chl = fat_shortname2uni(nls_disk, &work[i], 8 - i, + &uni_name[j++], opt_shortname, + de->lcase & CASE_LOWER_BASE); + if (chl <= 1) { + if (!isvfat) + ptname[i] = nocase ? c : fat_tolower(c); + i++; + if (c != ' ') { + name_len = i; + uni_len = j; + } + } else { + uni_len = j; + if (isvfat) + i += min(chl, 8-i); + else { + for (chi = 0; chi < chl && i < 8; chi++, i++) + ptname[i] = work[i]; + } + if (chl) + name_len = i; + } + } + + i = name_len; + j = uni_len; + fat_short2uni(nls_disk, ".", 1, &uni_name[j++]); + if (!isvfat) + ptname[i] = '.'; + i++; + + /* Extension */ + for (k = 8; k < MSDOS_NAME;) { + c = work[k]; + if (!c) + break; + chl = fat_shortname2uni(nls_disk, &work[k], MSDOS_NAME - k, + &uni_name[j++], opt_shortname, + de->lcase & CASE_LOWER_EXT); + if (chl <= 1) { + k++; + if (!isvfat) + ptname[i] = nocase ? c : fat_tolower(c); + i++; + if (c != ' ') { + name_len = i; + uni_len = j; + } + } else { + uni_len = j; + if (isvfat) { + int offset = min(chl, MSDOS_NAME-k); + k += offset; + i += offset; + } else { + for (chi = 0; chi < chl && k < MSDOS_NAME; + chi++, i++, k++) { + ptname[i] = work[k]; + } + } + if (chl) + name_len = i; + } + } + + if (name_len > 0) { + name_len += dotoffset; + + if (sbi->options.isvfat) { + uni_name[uni_len] = 0x0000; + name_len = fat_uni_to_x8(sb, uni_name, name, + FAT_MAX_SHORT_SIZE); + } + } + + return name_len; +} + +/* + * Return values: negative -> error/not found, 0 -> found. + */ +int fat_search_long(struct inode *inode, const unsigned char *name, + int name_len, struct fat_slot_info *sinfo) +{ + struct super_block *sb = inode->i_sb; + struct msdos_sb_info *sbi = MSDOS_SB(sb); + struct buffer_head *bh = NULL; + struct msdos_dir_entry *de; + unsigned char nr_slots; + wchar_t *unicode = NULL; + unsigned char bufname[FAT_MAX_SHORT_SIZE]; + loff_t cpos = 0; + int err, len; + + err = -ENOENT; + while (1) { + if (fat_get_entry(inode, &cpos, &bh, &de) == -1) + goto end_of_dir; +parse_record: + nr_slots = 0; + if (de->name[0] == DELETED_FLAG) + continue; + if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME)) + continue; + if (de->attr != ATTR_EXT && IS_FREE(de->name)) + continue; + if (de->attr == ATTR_EXT) { + int status = fat_parse_long(inode, &cpos, &bh, &de, + &unicode, &nr_slots); + if (status < 0) { + err = status; + goto end_of_dir; + } else if (status == PARSE_INVALID) + continue; + else if (status == PARSE_NOT_LONGNAME) + goto parse_record; + else if (status == PARSE_EOF) + goto end_of_dir; + } + + /* Never prepend '.' to hidden files here. + * That is done only for msdos mounts (and only when + * 'dotsOK=yes'); if we are executing here, it is in the + * context of a vfat mount. + */ + len = fat_parse_short(sb, de, bufname, 0); + if (len == 0) + continue; + + /* Compare shortname */ + if (fat_name_match(sbi, name, name_len, bufname, len)) + goto found; + + if (nr_slots) { + void *longname = unicode + FAT_MAX_UNI_CHARS; + int size = PATH_MAX - FAT_MAX_UNI_SIZE; + + /* Compare longname */ + len = fat_uni_to_x8(sb, unicode, longname, size); + if (fat_name_match(sbi, name, name_len, longname, len)) + goto found; + } + } + +found: + nr_slots++; /* include the de */ + sinfo->slot_off = cpos - nr_slots * sizeof(*de); + sinfo->nr_slots = nr_slots; + sinfo->de = de; + sinfo->bh = bh; + sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de); + err = 0; +end_of_dir: + if (unicode) + __putname(unicode); + + return err; +} +EXPORT_SYMBOL_GPL(fat_search_long); + +struct fat_ioctl_filldir_callback { + struct dir_context ctx; + void __user *dirent; + int result; + /* for dir ioctl */ + const char *longname; + int long_len; + const char *shortname; + int short_len; +}; + +static int __fat_readdir(struct inode *inode, struct file *file, + struct dir_context *ctx, int short_only, + struct fat_ioctl_filldir_callback *both) +{ + struct super_block *sb = inode->i_sb; + struct msdos_sb_info *sbi = MSDOS_SB(sb); + struct buffer_head *bh; + struct msdos_dir_entry *de; + unsigned char nr_slots; + wchar_t *unicode = NULL; + unsigned char bufname[FAT_MAX_SHORT_SIZE]; + int isvfat = sbi->options.isvfat; + const char *fill_name = NULL; + int fake_offset = 0; + loff_t cpos; + int short_len = 0, fill_len = 0; + int ret = 0; + + mutex_lock(&sbi->s_lock); + + cpos = ctx->pos; + /* Fake . and .. for the root directory. */ + if (inode->i_ino == MSDOS_ROOT_INO) { + if (!dir_emit_dots(file, ctx)) + goto out; + if (ctx->pos == 2) { + fake_offset = 1; + cpos = 0; + } + } + if (cpos & (sizeof(struct msdos_dir_entry) - 1)) { + ret = -ENOENT; + goto out; + } + + bh = NULL; +get_new: + if (fat_get_entry(inode, &cpos, &bh, &de) == -1) + goto end_of_dir; +parse_record: + nr_slots = 0; + /* + * Check for long filename entry, but if short_only, we don't + * need to parse long filename. + */ + if (isvfat && !short_only) { + if (de->name[0] == DELETED_FLAG) + goto record_end; + if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME)) + goto record_end; + if (de->attr != ATTR_EXT && IS_FREE(de->name)) + goto record_end; + } else { + if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name)) + goto record_end; + } + + if (isvfat && de->attr == ATTR_EXT) { + int status = fat_parse_long(inode, &cpos, &bh, &de, + &unicode, &nr_slots); + if (status < 0) { + bh = NULL; + ret = status; + goto end_of_dir; + } else if (status == PARSE_INVALID) + goto record_end; + else if (status == PARSE_NOT_LONGNAME) + goto parse_record; + else if (status == PARSE_EOF) + goto end_of_dir; + + if (nr_slots) { + void *longname = unicode + FAT_MAX_UNI_CHARS; + int size = PATH_MAX - FAT_MAX_UNI_SIZE; + int len = fat_uni_to_x8(sb, unicode, longname, size); + + fill_name = longname; + fill_len = len; + /* !both && !short_only, so we don't need shortname. */ + if (!both) + goto start_filldir; + + short_len = fat_parse_short(sb, de, bufname, + sbi->options.dotsOK); + if (short_len == 0) + goto record_end; + /* hack for fat_ioctl_filldir() */ + both->longname = fill_name; + both->long_len = fill_len; + both->shortname = bufname; + both->short_len = short_len; + fill_name = NULL; + fill_len = 0; + goto start_filldir; + } + } + + short_len = fat_parse_short(sb, de, bufname, sbi->options.dotsOK); + if (short_len == 0) + goto record_end; + + fill_name = bufname; + fill_len = short_len; + +start_filldir: + ctx->pos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry); + if (fake_offset && ctx->pos < 2) + ctx->pos = 2; + + if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME)) { + if (!dir_emit_dot(file, ctx)) + goto fill_failed; + } else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) { + if (!dir_emit_dotdot(file, ctx)) + goto fill_failed; + } else { + unsigned long inum; + loff_t i_pos = fat_make_i_pos(sb, bh, de); + struct inode *tmp = fat_iget(sb, i_pos); + if (tmp) { + inum = tmp->i_ino; + iput(tmp); + } else + inum = iunique(sb, MSDOS_ROOT_INO); + if (!dir_emit(ctx, fill_name, fill_len, inum, + (de->attr & ATTR_DIR) ? DT_DIR : DT_REG)) + goto fill_failed; + } + +record_end: + fake_offset = 0; + ctx->pos = cpos; + goto get_new; + +end_of_dir: + if (fake_offset && cpos < 2) + ctx->pos = 2; + else + ctx->pos = cpos; +fill_failed: + brelse(bh); + if (unicode) + __putname(unicode); +out: + mutex_unlock(&sbi->s_lock); + + return ret; +} + +static int fat_readdir(struct file *file, struct dir_context *ctx) +{ + return __fat_readdir(file_inode(file), file, ctx, 0, NULL); +} + +#define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type) \ +static bool func(struct dir_context *ctx, const char *name, int name_len, \ + loff_t offset, u64 ino, unsigned int d_type) \ +{ \ + struct fat_ioctl_filldir_callback *buf = \ + container_of(ctx, struct fat_ioctl_filldir_callback, ctx); \ + struct dirent_type __user *d1 = buf->dirent; \ + struct dirent_type __user *d2 = d1 + 1; \ + \ + if (buf->result) \ + return false; \ + buf->result++; \ + \ + if (name != NULL) { \ + /* dirent has only short name */ \ + if (name_len >= sizeof(d1->d_name)) \ + name_len = sizeof(d1->d_name) - 1; \ + \ + if (put_user(0, &d2->d_name[0]) || \ + put_user(0, &d2->d_reclen) || \ + copy_to_user(d1->d_name, name, name_len) || \ + put_user(0, d1->d_name + name_len) || \ + put_user(name_len, &d1->d_reclen)) \ + goto efault; \ + } else { \ + /* dirent has short and long name */ \ + const char *longname = buf->longname; \ + int long_len = buf->long_len; \ + const char *shortname = buf->shortname; \ + int short_len = buf->short_len; \ + \ + if (long_len >= sizeof(d1->d_name)) \ + long_len = sizeof(d1->d_name) - 1; \ + if (short_len >= sizeof(d1->d_name)) \ + short_len = sizeof(d1->d_name) - 1; \ + \ + if (copy_to_user(d2->d_name, longname, long_len) || \ + put_user(0, d2->d_name + long_len) || \ + put_user(long_len, &d2->d_reclen) || \ + put_user(ino, &d2->d_ino) || \ + put_user(offset, &d2->d_off) || \ + copy_to_user(d1->d_name, shortname, short_len) || \ + put_user(0, d1->d_name + short_len) || \ + put_user(short_len, &d1->d_reclen)) \ + goto efault; \ + } \ + return true; \ +efault: \ + buf->result = -EFAULT; \ + return false; \ +} + +FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent) + +static int fat_ioctl_readdir(struct inode *inode, struct file *file, + void __user *dirent, filldir_t filldir, + int short_only, int both) +{ + struct fat_ioctl_filldir_callback buf = { + .ctx.actor = filldir, + .dirent = dirent + }; + int ret; + + buf.dirent = dirent; + buf.result = 0; + inode_lock_shared(inode); + buf.ctx.pos = file->f_pos; + ret = -ENOENT; + if (!IS_DEADDIR(inode)) { + ret = __fat_readdir(inode, file, &buf.ctx, + short_only, both ? &buf : NULL); + file->f_pos = buf.ctx.pos; + } + inode_unlock_shared(inode); + if (ret >= 0) + ret = buf.result; + return ret; +} + +static long fat_dir_ioctl(struct file *filp, unsigned int cmd, + unsigned long arg) +{ + struct inode *inode = file_inode(filp); + struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg; + int short_only, both; + + switch (cmd) { + case VFAT_IOCTL_READDIR_SHORT: + short_only = 1; + both = 0; + break; + case VFAT_IOCTL_READDIR_BOTH: + short_only = 0; + both = 1; + break; + default: + return fat_generic_ioctl(filp, cmd, arg); + } + + /* + * Yes, we don't need this put_user() absolutely. However old + * code didn't return the right value. So, app use this value, + * in order to check whether it is EOF. + */ + if (put_user(0, &d1->d_reclen)) + return -EFAULT; + + return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir, + short_only, both); +} + +#ifdef CONFIG_COMPAT +#define VFAT_IOCTL_READDIR_BOTH32 _IOR('r', 1, struct compat_dirent[2]) +#define VFAT_IOCTL_READDIR_SHORT32 _IOR('r', 2, struct compat_dirent[2]) + +FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent) + +static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd, + unsigned long arg) +{ + struct inode *inode = file_inode(filp); + struct compat_dirent __user *d1 = compat_ptr(arg); + int short_only, both; + + switch (cmd) { + case VFAT_IOCTL_READDIR_SHORT32: + short_only = 1; + both = 0; + break; + case VFAT_IOCTL_READDIR_BOTH32: + short_only = 0; + both = 1; + break; + default: + return fat_generic_ioctl(filp, cmd, (unsigned long)arg); + } + + /* + * Yes, we don't need this put_user() absolutely. However old + * code didn't return the right value. So, app use this value, + * in order to check whether it is EOF. + */ + if (put_user(0, &d1->d_reclen)) + return -EFAULT; + + return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir, + short_only, both); +} +#endif /* CONFIG_COMPAT */ + +const struct file_operations fat_dir_operations = { + .llseek = generic_file_llseek, + .read = generic_read_dir, + .iterate_shared = fat_readdir, + .unlocked_ioctl = fat_dir_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = fat_compat_dir_ioctl, +#endif + .fsync = fat_file_fsync, +}; + +static int fat_get_short_entry(struct inode *dir, loff_t *pos, + struct buffer_head **bh, + struct msdos_dir_entry **de) +{ + while (fat_get_entry(dir, pos, bh, de) >= 0) { + /* free entry or long name entry or volume label */ + if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME)) + return 0; + } + return -ENOENT; +} + +/* + * The ".." entry can not provide the "struct fat_slot_info" information + * for inode, nor a usable i_pos. So, this function provides some information + * only. + * + * Since this function walks through the on-disk inodes within a directory, + * callers are responsible for taking any locks necessary to prevent the + * directory from changing. + */ +int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh, + struct msdos_dir_entry **de) +{ + loff_t offset = 0; + + *de = NULL; + while (fat_get_short_entry(dir, &offset, bh, de) >= 0) { + if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME)) + return 0; + } + return -ENOENT; +} +EXPORT_SYMBOL_GPL(fat_get_dotdot_entry); + +/* See if directory is empty */ +int fat_dir_empty(struct inode *dir) +{ + struct buffer_head *bh; + struct msdos_dir_entry *de; + loff_t cpos; + int result = 0; + + bh = NULL; + cpos = 0; + while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) { + if (strncmp(de->name, MSDOS_DOT , MSDOS_NAME) && + strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) { + result = -ENOTEMPTY; + break; + } + } + brelse(bh); + return result; +} +EXPORT_SYMBOL_GPL(fat_dir_empty); + +/* + * fat_subdirs counts the number of sub-directories of dir. It can be run + * on directories being created. + */ +int fat_subdirs(struct inode *dir) +{ + struct buffer_head *bh; + struct msdos_dir_entry *de; + loff_t cpos; + int count = 0; + + bh = NULL; + cpos = 0; + while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) { + if (de->attr & ATTR_DIR) + count++; + } + brelse(bh); + return count; +} + +/* + * Scans a directory for a given file (name points to its formatted name). + * Returns an error code or zero. + */ +int fat_scan(struct inode *dir, const unsigned char *name, + struct fat_slot_info *sinfo) +{ + struct super_block *sb = dir->i_sb; + + sinfo->slot_off = 0; + sinfo->bh = NULL; + while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh, + &sinfo->de) >= 0) { + if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) { + sinfo->slot_off -= sizeof(*sinfo->de); + sinfo->nr_slots = 1; + sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de); + return 0; + } + } + return -ENOENT; +} +EXPORT_SYMBOL_GPL(fat_scan); + +/* + * Scans a directory for a given logstart. + * Returns an error code or zero. + */ +int fat_scan_logstart(struct inode *dir, int i_logstart, + struct fat_slot_info *sinfo) +{ + struct super_block *sb = dir->i_sb; + + sinfo->slot_off = 0; + sinfo->bh = NULL; + while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh, + &sinfo->de) >= 0) { + if (fat_get_start(MSDOS_SB(sb), sinfo->de) == i_logstart) { + sinfo->slot_off -= sizeof(*sinfo->de); + sinfo->nr_slots = 1; + sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de); + return 0; + } + } + return -ENOENT; +} + +static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots) +{ + struct super_block *sb = dir->i_sb; + struct buffer_head *bh; + struct msdos_dir_entry *de, *endp; + int err = 0, orig_slots; + + while (nr_slots) { + bh = NULL; + if (fat_get_entry(dir, &pos, &bh, &de) < 0) { + err = -EIO; + break; + } + + orig_slots = nr_slots; + endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize); + while (nr_slots && de < endp) { + de->name[0] = DELETED_FLAG; + de++; + nr_slots--; + } + mark_buffer_dirty_inode(bh, dir); + if (IS_DIRSYNC(dir)) + err = sync_dirty_buffer(bh); + brelse(bh); + if (err) + break; + + /* pos is *next* de's position, so this does `- sizeof(de)' */ + pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de); + } + + return err; +} + +int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo) +{ + struct super_block *sb = dir->i_sb; + struct msdos_dir_entry *de; + struct buffer_head *bh; + int err = 0, nr_slots; + + /* + * First stage: Remove the shortname. By this, the directory + * entry is removed. + */ + nr_slots = sinfo->nr_slots; + de = sinfo->de; + sinfo->de = NULL; + bh = sinfo->bh; + sinfo->bh = NULL; + while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) { + de->name[0] = DELETED_FLAG; + de--; + nr_slots--; + } + mark_buffer_dirty_inode(bh, dir); + if (IS_DIRSYNC(dir)) + err = sync_dirty_buffer(bh); + brelse(bh); + if (err) + return err; + inode_inc_iversion(dir); + + if (nr_slots) { + /* + * Second stage: remove the remaining longname slots. + * (This directory entry is already removed, and so return + * the success) + */ + err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots); + if (err) { + fat_msg(sb, KERN_WARNING, + "Couldn't remove the long name slots"); + } + } + + fat_truncate_time(dir, NULL, S_ATIME|S_MTIME); + if (IS_DIRSYNC(dir)) + (void)fat_sync_inode(dir); + else + mark_inode_dirty(dir); + + return 0; +} +EXPORT_SYMBOL_GPL(fat_remove_entries); + +static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used, + struct buffer_head **bhs, int nr_bhs) +{ + struct super_block *sb = dir->i_sb; + sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus; + int err, i, n; + + /* Zeroing the unused blocks on this cluster */ + blknr += nr_used; + n = nr_used; + while (blknr < last_blknr) { + bhs[n] = sb_getblk(sb, blknr); + if (!bhs[n]) { + err = -ENOMEM; + goto error; + } + /* Avoid race with userspace read via bdev */ + lock_buffer(bhs[n]); + memset(bhs[n]->b_data, 0, sb->s_blocksize); + set_buffer_uptodate(bhs[n]); + unlock_buffer(bhs[n]); + mark_buffer_dirty_inode(bhs[n], dir); + + n++; + blknr++; + if (n == nr_bhs) { + if (IS_DIRSYNC(dir)) { + err = fat_sync_bhs(bhs, n); + if (err) + goto error; + } + for (i = 0; i < n; i++) + brelse(bhs[i]); + n = 0; + } + } + if (IS_DIRSYNC(dir)) { + err = fat_sync_bhs(bhs, n); + if (err) + goto error; + } + for (i = 0; i < n; i++) + brelse(bhs[i]); + + return 0; + +error: + for (i = 0; i < n; i++) + bforget(bhs[i]); + return err; +} + +int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts) +{ + struct super_block *sb = dir->i_sb; + struct msdos_sb_info *sbi = MSDOS_SB(sb); + struct buffer_head *bhs[MAX_BUF_PER_PAGE]; + struct msdos_dir_entry *de; + sector_t blknr; + __le16 date, time; + u8 time_cs; + int err, cluster; + + err = fat_alloc_clusters(dir, &cluster, 1); + if (err) + goto error; + + blknr = fat_clus_to_blknr(sbi, cluster); + bhs[0] = sb_getblk(sb, blknr); + if (!bhs[0]) { + err = -ENOMEM; + goto error_free; + } + + fat_time_unix2fat(sbi, ts, &time, &date, &time_cs); + + de = (struct msdos_dir_entry *)bhs[0]->b_data; + /* Avoid race with userspace read via bdev */ + lock_buffer(bhs[0]); + /* filling the new directory slots ("." and ".." entries) */ + memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME); + memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME); + de->attr = de[1].attr = ATTR_DIR; + de[0].lcase = de[1].lcase = 0; + de[0].time = de[1].time = time; + de[0].date = de[1].date = date; + if (sbi->options.isvfat) { + /* extra timestamps */ + de[0].ctime = de[1].ctime = time; + de[0].ctime_cs = de[1].ctime_cs = time_cs; + de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date; + } else { + de[0].ctime = de[1].ctime = 0; + de[0].ctime_cs = de[1].ctime_cs = 0; + de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0; + } + fat_set_start(&de[0], cluster); + fat_set_start(&de[1], MSDOS_I(dir)->i_logstart); + de[0].size = de[1].size = 0; + memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de)); + set_buffer_uptodate(bhs[0]); + unlock_buffer(bhs[0]); + mark_buffer_dirty_inode(bhs[0], dir); + + err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE); + if (err) + goto error_free; + + return cluster; + +error_free: + fat_free_clusters(dir, cluster); +error: + return err; +} +EXPORT_SYMBOL_GPL(fat_alloc_new_dir); + +static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots, + int *nr_cluster, struct msdos_dir_entry **de, + struct buffer_head **bh, loff_t *i_pos) +{ + struct super_block *sb = dir->i_sb; + struct msdos_sb_info *sbi = MSDOS_SB(sb); + struct buffer_head *bhs[MAX_BUF_PER_PAGE]; + sector_t blknr, start_blknr, last_blknr; + unsigned long size, copy; + int err, i, n, offset, cluster[2]; + + /* + * The minimum cluster size is 512bytes, and maximum entry + * size is 32*slots (672bytes). So, iff the cluster size is + * 512bytes, we may need two clusters. + */ + size = nr_slots * sizeof(struct msdos_dir_entry); + *nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits; + BUG_ON(*nr_cluster > 2); + + err = fat_alloc_clusters(dir, cluster, *nr_cluster); + if (err) + goto error; + + /* + * First stage: Fill the directory entry. NOTE: This cluster + * is not referenced from any inode yet, so updates order is + * not important. + */ + i = n = copy = 0; + do { + start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]); + last_blknr = start_blknr + sbi->sec_per_clus; + while (blknr < last_blknr) { + bhs[n] = sb_getblk(sb, blknr); + if (!bhs[n]) { + err = -ENOMEM; + goto error_nomem; + } + + /* fill the directory entry */ + copy = min(size, sb->s_blocksize); + /* Avoid race with userspace read via bdev */ + lock_buffer(bhs[n]); + memcpy(bhs[n]->b_data, slots, copy); + set_buffer_uptodate(bhs[n]); + unlock_buffer(bhs[n]); + mark_buffer_dirty_inode(bhs[n], dir); + slots += copy; + size -= copy; + if (!size) + break; + n++; + blknr++; + } + } while (++i < *nr_cluster); + + memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy); + offset = copy - sizeof(struct msdos_dir_entry); + get_bh(bhs[n]); + *bh = bhs[n]; + *de = (struct msdos_dir_entry *)((*bh)->b_data + offset); + *i_pos = fat_make_i_pos(sb, *bh, *de); + + /* Second stage: clear the rest of cluster, and write outs */ + err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE); + if (err) + goto error_free; + + return cluster[0]; + +error_free: + brelse(*bh); + *bh = NULL; + n = 0; +error_nomem: + for (i = 0; i < n; i++) + bforget(bhs[i]); + fat_free_clusters(dir, cluster[0]); +error: + return err; +} + +int fat_add_entries(struct inode *dir, void *slots, int nr_slots, + struct fat_slot_info *sinfo) +{ + struct super_block *sb = dir->i_sb; + struct msdos_sb_info *sbi = MSDOS_SB(sb); + struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */ + struct msdos_dir_entry *de; + int err, free_slots, i, nr_bhs; + loff_t pos, i_pos; + + sinfo->nr_slots = nr_slots; + + /* First stage: search free directory entries */ + free_slots = nr_bhs = 0; + bh = prev = NULL; + pos = 0; + err = -ENOSPC; + while (fat_get_entry(dir, &pos, &bh, &de) > -1) { + /* check the maximum size of directory */ + if (pos >= FAT_MAX_DIR_SIZE) + goto error; + + if (IS_FREE(de->name)) { + if (prev != bh) { + get_bh(bh); + bhs[nr_bhs] = prev = bh; + nr_bhs++; + } + free_slots++; + if (free_slots == nr_slots) + goto found; + } else { + for (i = 0; i < nr_bhs; i++) + brelse(bhs[i]); + prev = NULL; + free_slots = nr_bhs = 0; + } + } + if (dir->i_ino == MSDOS_ROOT_INO) { + if (!is_fat32(sbi)) + goto error; + } else if (MSDOS_I(dir)->i_start == 0) { + fat_msg(sb, KERN_ERR, "Corrupted directory (i_pos %lld)", + MSDOS_I(dir)->i_pos); + err = -EIO; + goto error; + } + +found: + err = 0; + pos -= free_slots * sizeof(*de); + nr_slots -= free_slots; + if (free_slots) { + /* + * Second stage: filling the free entries with new entries. + * NOTE: If this slots has shortname, first, we write + * the long name slots, then write the short name. + */ + int size = free_slots * sizeof(*de); + int offset = pos & (sb->s_blocksize - 1); + int long_bhs = nr_bhs - (nr_slots == 0); + + /* Fill the long name slots. */ + for (i = 0; i < long_bhs; i++) { + int copy = min_t(int, sb->s_blocksize - offset, size); + memcpy(bhs[i]->b_data + offset, slots, copy); + mark_buffer_dirty_inode(bhs[i], dir); + offset = 0; + slots += copy; + size -= copy; + } + if (long_bhs && IS_DIRSYNC(dir)) + err = fat_sync_bhs(bhs, long_bhs); + if (!err && i < nr_bhs) { + /* Fill the short name slot. */ + int copy = min_t(int, sb->s_blocksize - offset, size); + memcpy(bhs[i]->b_data + offset, slots, copy); + mark_buffer_dirty_inode(bhs[i], dir); + if (IS_DIRSYNC(dir)) + err = sync_dirty_buffer(bhs[i]); + } + for (i = 0; i < nr_bhs; i++) + brelse(bhs[i]); + if (err) + goto error_remove; + } + + if (nr_slots) { + int cluster, nr_cluster; + + /* + * Third stage: allocate the cluster for new entries. + * And initialize the cluster with new entries, then + * add the cluster to dir. + */ + cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster, + &de, &bh, &i_pos); + if (cluster < 0) { + err = cluster; + goto error_remove; + } + err = fat_chain_add(dir, cluster, nr_cluster); + if (err) { + fat_free_clusters(dir, cluster); + goto error_remove; + } + if (dir->i_size & (sbi->cluster_size - 1)) { + fat_fs_error(sb, "Odd directory size"); + dir->i_size = (dir->i_size + sbi->cluster_size - 1) + & ~((loff_t)sbi->cluster_size - 1); + } + dir->i_size += nr_cluster << sbi->cluster_bits; + MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits; + } + sinfo->slot_off = pos; + sinfo->de = de; + sinfo->bh = bh; + sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de); + + return 0; + +error: + brelse(bh); + for (i = 0; i < nr_bhs; i++) + brelse(bhs[i]); + return err; + +error_remove: + brelse(bh); + if (free_slots) + __fat_remove_entries(dir, pos, free_slots); + return err; +} +EXPORT_SYMBOL_GPL(fat_add_entries); |