// 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/filelock.h>#include <linux/hex.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);} /* * Like fat_get_entry(), but honour the FAT end-of-directory marker: * a dirent whose first name byte is NUL terminates iteration per the * spec, which also guarantees that every following slot is zeroed. * Skip straight to the end of the directory so the next call returns * -1 from fat_bmap() without re-reading the trailing zero slots, and * so callers that persist *pos across invocations (e.g. readdir's * ctx->pos) keep reporting EOD. Release *bh and set it to NULL to * match fat_get_entry()'s contract that *bh is NULL on the -1 return. */static int fat_get_entry_eod(struct inode *dir, loff_t *pos, struct buffer_head **bh, struct msdos_dir_entry **de){ int err = fat_get_entry(dir, pos, bh, de); if (err == 0 && (*de)->name[0] == 0) { brelse(*bh); *bh = NULL; *pos = dir->i_size; return -1; } return err;} /* * 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 intfat_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 intfat_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 intfat_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. * * @dir: Pointer to the inode that represents the directory. * @pos: On input, contains the starting position to read from. * On output, updated with the new position. * @bh: Pointer to the buffer head that may be used for reading directory * entries. May be updated. * @de: On input, points to the current directory entry. * On output, points to the next directory entry. * @unicode: Pointer to a buffer where the parsed Unicode long filename will be * stored. * @nr_slots: Pointer to a variable that will store the number of longname * slots found. * * 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_eod(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.Lines 1–500 of 1467. 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// 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/filelock.h> #include <linux/hex.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); } /* * Like fat_get_entry(), but honour the FAT end-of-directory marker: * a dirent whose first name byte is NUL terminates iteration per the * spec, which also guarantees that every following slot is zeroed. * Skip straight to the end of the directory so the next call returns * -1 from fat_bmap() without re-reading the trailing zero slots, and * so callers that persist *pos across invocations (e.g. readdir's * ctx->pos) keep reporting EOD. Release *bh and set it to NULL to * match fat_get_entry()'s contract that *bh is NULL on the -1 return. */ static int fat_get_entry_eod(struct inode *dir, loff_t *pos, struct buffer_head **bh, struct msdos_dir_entry **de) { int err = fat_get_entry(dir, pos, bh, de); if (err == 0 && (*de)->name[0] == 0) { brelse(*bh); *bh = NULL; *pos = dir->i_size; return -1; } return err; } /* * 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. * * @dir: Pointer to the inode that represents the directory. * @pos: On input, contains the starting position to read from. * On output, updated with the new position. * @bh: Pointer to the buffer head that may be used for reading directory * entries. May be updated. * @de: On input, points to the current directory entry. * On output, points to the next directory entry. * @unicode: Pointer to a buffer where the parsed Unicode long filename will be * stored. * @nr_slots: Pointer to a variable that will store the number of longname * slots found. * * 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_eod(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.