/* * linux/fs/msdos/namei.c * * Written 1992,1993 by Werner Almesberger * Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu> * Rewritten for constant inumbers 1999 by Al Viro */ #include <linux/module.h> #include <linux/time.h> #include <linux/buffer_head.h> #include <linux/msdos_fs.h> #include <linux/smp_lock.h> /* MS-DOS "device special files" */ static const unsigned char *reserved_names[] = { "CON ", "PRN ", "NUL ", "AUX ", "LPT1 ", "LPT2 ", "LPT3 ", "LPT4 ", "COM1 ", "COM2 ", "COM3 ", "COM4 ", NULL }; /* Characters that are undesirable in an MS-DOS file name */ static unsigned char bad_chars[] = "*?<>|\""; static unsigned char bad_if_strict_pc[] = "+=,; "; /* GEMDOS is less restrictive */ static unsigned char bad_if_strict_atari[] = " "; #define bad_if_strict(opts) \ ((opts)->atari ? bad_if_strict_atari : bad_if_strict_pc) /***** Formats an MS-DOS file name. Rejects invalid names. */ static int msdos_format_name(const unsigned char *name, int len, unsigned char *res, struct fat_mount_options *opts) /* * name is the proposed name, len is its length, res is * the resulting name, opts->name_check is either (r)elaxed, * (n)ormal or (s)trict, opts->dotsOK allows dots at the * beginning of name (for hidden files) */ { unsigned char *walk; const unsigned char **reserved; unsigned char c; int space; if (name[0] == '.') { /* dotfile because . and .. already done */ if (opts->dotsOK) { /* Get rid of dot - test for it elsewhere */ name++; len--; } else if (!opts->atari) return -EINVAL; } /* * disallow names that _really_ start with a dot for MS-DOS, * GEMDOS does not care */ space = !opts->atari; c = 0; for (walk = res; len && walk - res < 8; walk++) { c = *name++; len--; if (opts->name_check != 'r' && strchr(bad_chars, c)) return -EINVAL; if (opts->name_check == 's' && strchr(bad_if_strict(opts), c)) return -EINVAL; if (c >= 'A' && c <= 'Z' && opts->name_check == 's') return -EINVAL; if (c < ' ' || c == ':' || c == '\\') return -EINVAL; /* * 0xE5 is legal as a first character, but we must substitute * 0x05 because 0xE5 marks deleted files. Yes, DOS really * does this. * It seems that Microsoft hacked DOS to support non-US * characters after the 0xE5 character was already in use to * mark deleted files. */ if ((res == walk) && (c == 0xE5)) c = 0x05; if (c == '.') break; space = (c == ' '); *walk = (!opts->nocase && c >= 'a' && c <= 'z') ? c - 32 : c; } if (space) return -EINVAL; if (opts->name_check == 's' && len && c != '.') { c = *name++; len--; if (c != '.') return -EINVAL; } while (c != '.' && len--) c = *name++; if (c == '.') { while (walk - res < 8) *walk++ = ' '; while (len > 0 && walk - res < MSDOS_NAME) { c = *name++; len--; if (opts->name_check != 'r' && strchr(bad_chars, c)) return -EINVAL; if (opts->name_check == 's' && strchr(bad_if_strict(opts), c)) return -EINVAL; if (c < ' ' || c == ':' || c == '\\') return -EINVAL; if (c == '.') { if (opts->name_check == 's') return -EINVAL; break; } if (c >= 'A' && c <= 'Z' && opts->name_check == 's') return -EINVAL; space = c == ' '; if (!opts->nocase && c >= 'a' && c <= 'z') *walk++ = c - 32; else *walk++ = c; } if (space) return -EINVAL; if (opts->name_check == 's' && len) return -EINVAL; } while (walk - res < MSDOS_NAME) *walk++ = ' '; if (!opts->atari) /* GEMDOS is less stupid and has no reserved names */ for (reserved = reserved_names; *reserved; reserved++) if (!strncmp(res, *reserved, 8)) return -EINVAL; return 0; } /***** Locates a directory entry. Uses unformatted name. */ static int msdos_find(struct inode *dir, const unsigned char *name, int len, struct fat_slot_info *sinfo) { struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb); unsigned char msdos_name[MSDOS_NAME]; int err; err = msdos_format_name(name, len, msdos_name, &sbi->options); if (err) return -ENOENT; err = fat_scan(dir, msdos_name, sinfo); if (!err && sbi->options.dotsOK) { if (name[0] == '.') { if (!(sinfo->de->attr & ATTR_HIDDEN)) err = -ENOENT; } else { if (sinfo->de->attr & ATTR_HIDDEN) err = -ENOENT; } if (err) brelse(sinfo->bh); } return err; } /* * Compute the hash for the msdos name corresponding to the dentry. * Note: if the name is invalid, we leave the hash code unchanged so * that the existing dentry can be used. The msdos fs routines will * return ENOENT or EINVAL as appropriate. */ static int msdos_hash(struct dentry *dentry, struct qstr *qstr) { struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options; unsigned char msdos_name[MSDOS_NAME]; int error; error = msdos_format_name(qstr->name, qstr->len, msdos_name, options); if (!error) qstr->hash = full_name_hash(msdos_name, MSDOS_NAME); return 0; } /* * Compare two msdos names. If either of the names are invalid, * we fall back to doing the standard name comparison. */ static int msdos_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b) { struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options; unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME]; int error; error = msdos_format_name(a->name, a->len, a_msdos_name, options); if (error) goto old_compare; error = msdos_format_name(b->name, b->len, b_msdos_name, options); if (error) goto old_compare; error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME); out: return error; old_compare: error = 1; if (a->len == b->len) error = memcmp(a->name, b->name, a->len); goto out; } static struct dentry_operations msdos_dentry_operations = { .d_hash = msdos_hash, .d_compare = msdos_cmp, }; /* * AV. Wrappers for FAT sb operations. Is it wise? */ /***** Get inode using directory and name */ static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) { struct super_block *sb = dir->i_sb; struct fat_slot_info sinfo; struct inode *inode = NULL; int res; dentry->d_op = &msdos_dentry_operations; lock_kernel(); res = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo); if (res == -ENOENT) goto add; if (res < 0) goto out; inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); brelse(sinfo.bh); if (IS_ERR(inode)) { res = PTR_ERR(inode); goto out; } add: res = 0; dentry = d_splice_alias(inode, dentry); if (dentry) dentry->d_op = &msdos_dentry_operations; out: unlock_kernel(); if (!res) return dentry; return ERR_PTR(res); } /***** Creates a directory entry (name is already formatted). */ static int msdos_add_entry(struct inode *dir, const unsigned char *name, int is_dir, int is_hid, int cluster, struct timespec *ts, struct fat_slot_info *sinfo) { struct msdos_dir_entry de; __le16 time, date; int err; memcpy(de.name, name, MSDOS_NAME); de.attr = is_dir ? ATTR_DIR : ATTR_ARCH; if (is_hid) de.attr |= ATTR_HIDDEN; de.lcase = 0; fat_date_unix2dos(ts->tv_sec, &time, &date); de.cdate = de.adate = 0; de.ctime = 0; de.ctime_cs = 0; de.time = time; de.date = date; de.start = cpu_to_le16(cluster); de.starthi = cpu_to_le16(cluster >> 16); de.size = 0; err = fat_add_entries(dir, &de, 1, sinfo); if (err) return err; dir->i_ctime = dir->i_mtime = *ts; if (IS_DIRSYNC(dir)) (void)fat_sync_inode(dir); else mark_inode_dirty(dir); return 0; } /***** Create a file */ static int msdos_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd) { struct super_block *sb = dir->i_sb; struct inode *inode; struct fat_slot_info sinfo; struct timespec ts; unsigned char msdos_name[MSDOS_NAME]; int err, is_hid; lock_kernel(); err = msdos_format_name(dentry->d_name.name, dentry->d_name.len, msdos_name, &MSDOS_SB(sb)->options); if (err) goto out; is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.'); /* Have to do it due to foo vs. .foo conflicts */ if (!fat_scan(dir, msdos_name, &sinfo)) { brelse(sinfo.bh); err = -EINVAL; goto out; } ts = CURRENT_TIME_SEC; err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo); if (err) goto out; inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); brelse(sinfo.bh); if (IS_ERR(inode)) { err = PTR_ERR(inode); goto out; } inode->i_mtime = inode->i_atime = inode->i_ctime = ts; /* timestamp is already written, so mark_inode_dirty() is unneeded. */ d_instantiate(dentry, inode); out: unlock_kernel(); return err; } /***** Remove a directory */ static int msdos_rmdir(struct inode *dir, struct dentry *dentry) { struct inode *inode = dentry->d_inode; struct fat_slot_info sinfo; int err; lock_kernel(); /* * Check whether the directory is not in use, then check * whether it is empty. */ err = fat_dir_empty(inode); if (err) goto out; err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo); if (err) goto out; err = fat_remove_entries(dir, &sinfo); /* and releases bh */ if (err) goto out; dir->i_nlink--; inode->i_nlink = 0; inode->i_ctime = CURRENT_TIME_SEC; fat_detach(inode); out: unlock_kernel(); return err; } /***** Make a directory */ static int msdos_mkdir(struct inode *dir, struct dentry *dentry, int mode) { struct super_block *sb = dir->i_sb; struct fat_slot_info sinfo; struct inode *inode; unsigned char msdos_name[MSDOS_NAME]; struct timespec ts; int err, is_hid, cluster; lock_kernel(); err = msdos_format_name(dentry->d_name.name, dentry->d_name.len, msdos_name, &MSDOS_SB(sb)->options); if (err) goto out; is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.'); /* foo vs .foo situation */ if (!fat_scan(dir, msdos_name, &sinfo)) { brelse(sinfo.bh); err = -EINVAL; goto out; } ts = CURRENT_TIME_SEC; cluster = fat_alloc_new_dir(dir, &ts); if (cluster < 0) { err = cluster; goto out; } err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo); if (err) goto out_free; dir->i_nlink++; inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); brelse(sinfo.bh); if (IS_ERR(inode)) { err = PTR_ERR(inode); /* the directory was completed, just return a error */ goto out; } inode->i_nlink = 2; inode->i_mtime = inode->i_atime = inode->i_ctime = ts; /* timestamp is already written, so mark_inode_dirty() is unneeded. */ d_instantiate(dentry, inode); unlock_kernel(); return 0; out_free: fat_free_clusters(dir, cluster); out: unlock_kernel(); return err; } /***** Unlink a file */ static int msdos_unlink(struct inode *dir, struct dentry *dentry) { struct inode *inode = dentry->d_inode; struct fat_slot_info sinfo; int err; lock_kernel(); err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo); if (err) goto out; err = fat_remove_entries(dir, &sinfo); /* and releases bh */ if (err) goto out; inode->i_nlink = 0; inode->i_ctime = CURRENT_TIME_SEC; fat_detach(inode); out: unlock_kernel(); return err; } static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name, struct dentry *old_dentry, struct inode *new_dir, unsigned char *new_name, struct dentry *new_dentry, int is_hid) { struct buffer_head *dotdot_bh; struct msdos_dir_entry *dotdot_de; loff_t dotdot_i_pos; struct inode *old_inode, *new_inode; struct fat_slot_info old_sinfo, sinfo; struct timespec ts; int err, old_attrs, is_dir, update_dotdot, corrupt = 0; old_sinfo.bh = sinfo.bh = dotdot_bh = NULL; old_inode = old_dentry->d_inode; new_inode = new_dentry->d_inode; err = fat_scan(old_dir, old_name, &old_sinfo); if (err) { err = -EIO; goto out; } is_dir = S_ISDIR(old_inode->i_mode); update_dotdot = (is_dir && old_dir != new_dir); if (update_dotdot) { if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de, &dotdot_i_pos) < 0) { err = -EIO; goto out; } } old_attrs = MSDOS_I(old_inode)->i_attrs; err = fat_scan(new_dir, new_name, &sinfo); if (!err) { if (!new_inode) { /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */ if (sinfo.de != old_sinfo.de) { err = -EINVAL; goto out; } if (is_hid) MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN; else MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN; if (IS_DIRSYNC(old_dir)) { err = fat_sync_inode(old_inode); if (err) { MSDOS_I(old_inode)->i_attrs = old_attrs; goto out; } } else mark_inode_dirty(old_inode); old_dir->i_version++; old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC; if (IS_DIRSYNC(old_dir)) (void)fat_sync_inode(old_dir); else mark_inode_dirty(old_dir); goto out; } } ts = CURRENT_TIME_SEC; if (new_inode) { if (err) goto out; if (MSDOS_I(new_inode)->i_pos != sinfo.i_pos) { /* WTF??? Cry and fail. */ printk(KERN_WARNING "msdos_rename: fs corrupted\n"); goto out; } if (is_dir) { err = fat_dir_empty(new_inode); if (err) goto out; } fat_detach(new_inode); } else { err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0, &ts, &sinfo); if (err) goto out; } new_dir->i_version++; fat_detach(old_inode); fat_attach(old_inode, sinfo.i_pos); if (is_hid) MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN; else MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN; if (IS_DIRSYNC(new_dir)) { err = fat_sync_inode(old_inode); if (err) goto error_inode; } else mark_inode_dirty(old_inode); if (update_dotdot) { int start = MSDOS_I(new_dir)->i_logstart; dotdot_de->start = cpu_to_le16(start); dotdot_de->starthi = cpu_to_le16(start >> 16); mark_buffer_dirty(dotdot_bh); if (IS_DIRSYNC(new_dir)) { err = sync_dirty_buffer(dotdot_bh); if (err) goto error_dotdot; } old_dir->i_nlink--; if (!new_inode) new_dir->i_nlink++; } err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */ old_sinfo.bh = NULL; if (err) goto error_dotdot; old_dir->i_version++; old_dir->i_ctime = old_dir->i_mtime = ts; if (IS_DIRSYNC(old_dir)) (void)fat_sync_inode(old_dir); else mark_inode_dirty(old_dir); if (new_inode) { if (is_dir) new_inode->i_nlink -= 2; else new_inode->i_nlink--; new_inode->i_ctime = ts; } out: brelse(sinfo.bh); brelse(dotdot_bh); brelse(old_sinfo.bh); return err; error_dotdot: /* data cluster is shared, serious corruption */ corrupt = 1; if (update_dotdot) { int start = MSDOS_I(old_dir)->i_logstart; dotdot_de->start = cpu_to_le16(start); dotdot_de->starthi = cpu_to_le16(start >> 16); mark_buffer_dirty(dotdot_bh); corrupt |= sync_dirty_buffer(dotdot_bh); } error_inode: fat_detach(old_inode); fat_attach(old_inode, old_sinfo.i_pos); MSDOS_I(old_inode)->i_attrs = old_attrs; if (new_inode) { fat_attach(new_inode, sinfo.i_pos); if (corrupt) corrupt |= fat_sync_inode(new_inode); } else { /* * If new entry was not sharing the data cluster, it * shouldn't be serious corruption. */ int err2 = fat_remove_entries(new_dir, &sinfo); if (corrupt) corrupt |= err2; sinfo.bh = NULL; } if (corrupt < 0) { fat_fs_panic(new_dir->i_sb, "%s: Filesystem corrupted (i_pos %lld)", __FUNCTION__, sinfo.i_pos); } goto out; } /***** Rename, a wrapper for rename_same_dir & rename_diff_dir */ static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) { unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME]; int err, is_hid; lock_kernel(); err = msdos_format_name(old_dentry->d_name.name, old_dentry->d_name.len, old_msdos_name, &MSDOS_SB(old_dir->i_sb)->options); if (err) goto out; err = msdos_format_name(new_dentry->d_name.name, new_dentry->d_name.len, new_msdos_name, &MSDOS_SB(new_dir->i_sb)->options); if (err) goto out; is_hid = (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.'); err = do_msdos_rename(old_dir, old_msdos_name, old_dentry, new_dir, new_msdos_name, new_dentry, is_hid); out: unlock_kernel(); return err; } static struct inode_operations msdos_dir_inode_operations = { .create = msdos_create, .lookup = msdos_lookup, .unlink = msdos_unlink, .mkdir = msdos_mkdir, .rmdir = msdos_rmdir, .rename = msdos_rename, .setattr = fat_notify_change, }; static int msdos_fill_super(struct super_block *sb, void *data, int silent) { int res; res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0); if (res) return res; sb->s_flags |= MS_NOATIME; sb->s_root->d_op = &msdos_dentry_operations; return 0; } static struct super_block *msdos_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data) { return get_sb_bdev(fs_type, flags, dev_name, data, msdos_fill_super); } static struct file_system_type msdos_fs_type = { .owner = THIS_MODULE, .name = "msdos", .get_sb = msdos_get_sb, .kill_sb = kill_block_super, .fs_flags = FS_REQUIRES_DEV, }; static int __init init_msdos_fs(void) { return register_filesystem(&msdos_fs_type); } static void __exit exit_msdos_fs(void) { unregister_filesystem(&msdos_fs_type); } MODULE_LICENSE("GPL"); MODULE_AUTHOR("Werner Almesberger"); MODULE_DESCRIPTION("MS-DOS filesystem support"); module_init(init_msdos_fs) module_exit(exit_msdos_fs)