/* * Copyright (C) 2007 Red Hat. All rights reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public * License v2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public * License along with this program; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 021110-1307, USA. */ #include <linux/init.h> #include <linux/fs.h> #include <linux/slab.h> #include <linux/rwsem.h> #include <linux/xattr.h> #include "ctree.h" #include "btrfs_inode.h" #include "transaction.h" #include "xattr.h" #include "disk-io.h" static struct xattr_handler *btrfs_xattr_handler_map[] = { [BTRFS_XATTR_INDEX_USER] = &btrfs_xattr_user_handler, #ifdef CONFIG_FS_POSIX_ACL // [BTRFS_XATTR_INDEX_POSIX_ACL_ACCESS] = &btrfs_xattr_acl_access_handler, // [BTRFS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &btrfs_xattr_acl_default_handler, #endif [BTRFS_XATTR_INDEX_TRUSTED] = &btrfs_xattr_trusted_handler, [BTRFS_XATTR_INDEX_SECURITY] = &btrfs_xattr_security_handler, // [BTRFS_XATTR_INDEX_SYSTEM] = &btrfs_xattr_system_handler, }; struct xattr_handler *btrfs_xattr_handlers[] = { &btrfs_xattr_user_handler, #ifdef CONFIG_FS_POSIX_ACL // &btrfs_xattr_acl_access_handler, // &btrfs_xattr_acl_default_handler, #endif &btrfs_xattr_trusted_handler, &btrfs_xattr_security_handler, // &btrfs_xattr_system_handler, NULL, }; /* * @param name - the xattr name * @return - the xattr_handler for the xattr, NULL if its not found * * use this with listxattr where we don't already know the type of xattr we * have */ static struct xattr_handler *find_btrfs_xattr_handler(struct extent_buffer *l, unsigned long name_ptr, u16 name_len) { struct xattr_handler *handler = NULL; int i = 0; for (handler = btrfs_xattr_handlers[i]; handler != NULL; i++, handler = btrfs_xattr_handlers[i]) { u16 prefix_len = strlen(handler->prefix); if (name_len < prefix_len) continue; if (memcmp_extent_buffer(l, handler->prefix, name_ptr, prefix_len) == 0) break; } return handler; } /* * @param name_index - the index for the xattr handler * @return the xattr_handler if we found it, NULL otherwise * * use this if we know the type of the xattr already */ static struct xattr_handler *btrfs_xattr_handler(int name_index) { struct xattr_handler *handler = NULL; if (name_index >= 0 && name_index < ARRAY_SIZE(btrfs_xattr_handler_map)) handler = btrfs_xattr_handler_map[name_index]; return handler; } static inline char *get_name(const char *name, int name_index) { char *ret = NULL; struct xattr_handler *handler = btrfs_xattr_handler(name_index); int prefix_len; if (!handler) return ret; prefix_len = strlen(handler->prefix); ret = kmalloc(strlen(name) + prefix_len + 1, GFP_KERNEL); if (!ret) return ret; memcpy(ret, handler->prefix, prefix_len); memcpy(ret+prefix_len, name, strlen(name)); ret[prefix_len + strlen(name)] = '\0'; return ret; } size_t btrfs_xattr_generic_list(struct inode *inode, char *list, size_t list_size, const char *name, size_t name_len) { if (list && (name_len+1) <= list_size) { memcpy(list, name, name_len); list[name_len] = '\0'; } else return -ERANGE; return name_len+1; } ssize_t btrfs_xattr_get(struct inode *inode, int name_index, const char *attr_name, void *buffer, size_t size) { struct btrfs_dir_item *di; struct btrfs_root *root = BTRFS_I(inode)->root; struct btrfs_path *path; struct extent_buffer *leaf; struct xattr_handler *handler = btrfs_xattr_handler(name_index); int ret = 0; unsigned long data_ptr; char *name; if (!handler) return -EOPNOTSUPP; name = get_name(attr_name, name_index); if (!name) return -ENOMEM; path = btrfs_alloc_path(); if (!path) { kfree(name); return -ENOMEM; } /* lookup the xattr by name */ di = btrfs_lookup_xattr(NULL, root, path, inode->i_ino, name, strlen(name), 0); if (!di || IS_ERR(di)) { ret = -ENODATA; goto out; } leaf = path->nodes[0]; /* if size is 0, that means we want the size of the attr */ if (!size) { ret = btrfs_dir_data_len(leaf, di); goto out; } /* now get the data out of our dir_item */ if (btrfs_dir_data_len(leaf, di) > size) { ret = -ERANGE; goto out; } data_ptr = (unsigned long)((char *)(di + 1) + btrfs_dir_name_len(leaf, di)); read_extent_buffer(leaf, buffer, data_ptr, btrfs_dir_data_len(leaf, di)); ret = btrfs_dir_data_len(leaf, di); out: kfree(name); btrfs_free_path(path); return ret; } int btrfs_xattr_set(struct inode *inode, int name_index, const char *attr_name, const void *value, size_t size, int flags) { struct btrfs_dir_item *di; struct btrfs_root *root = BTRFS_I(inode)->root; struct btrfs_trans_handle *trans; struct btrfs_path *path; struct xattr_handler *handler = btrfs_xattr_handler(name_index); char *name; int ret = 0, mod = 0; if (!handler) return -EOPNOTSUPP; name = get_name(attr_name, name_index); if (!name) return -ENOMEM; path = btrfs_alloc_path(); if (!path) { kfree(name); return -ENOMEM; } trans = btrfs_start_transaction(root, 1); btrfs_set_trans_block_group(trans, inode); /* first lets see if we already have this xattr */ di = btrfs_lookup_xattr(trans, root, path, inode->i_ino, name, strlen(name), -1); if (IS_ERR(di)) { ret = PTR_ERR(di); goto out; } /* ok we already have this xattr, lets remove it */ if (di) { /* if we want create only exit */ if (flags & XATTR_CREATE) { ret = -EEXIST; goto out; } ret = btrfs_delete_one_dir_name(trans, root, path, di); if (ret) goto out; btrfs_release_path(root, path); /* if we don't have a value then we are removing the xattr */ if (!value) { mod = 1; goto out; } } else if (flags & XATTR_REPLACE) { /* we couldn't find the attr to replace, so error out */ ret = -ENODATA; goto out; } /* ok we have to create a completely new xattr */ ret = btrfs_insert_xattr_item(trans, root, name, strlen(name), value, size, inode->i_ino); if (ret) goto out; mod = 1; out: if (mod) { inode->i_ctime = CURRENT_TIME; ret = btrfs_update_inode(trans, root, inode); } btrfs_end_transaction(trans, root); kfree(name); btrfs_free_path(path); return ret; } ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size) { struct btrfs_key key, found_key; struct inode *inode = dentry->d_inode; struct btrfs_root *root = BTRFS_I(inode)->root; struct btrfs_path *path; struct btrfs_item *item; struct extent_buffer *leaf; struct btrfs_dir_item *di; struct xattr_handler *handler; int ret = 0, slot, advance; size_t total_size = 0, size_left = size, written; unsigned long name_ptr; char *name; u32 nritems; /* * ok we want all objects associated with this id. * NOTE: we set key.offset = 0; because we want to start with the * first xattr that we find and walk forward */ key.objectid = inode->i_ino; btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY); key.offset = 0; path = btrfs_alloc_path(); if (!path) return -ENOMEM; path->reada = 2; /* search for our xattrs */ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto err; ret = 0; advance = 0; while (1) { leaf = path->nodes[0]; nritems = btrfs_header_nritems(leaf); slot = path->slots[0]; /* this is where we start walking through the path */ if (advance || slot >= nritems) { /* * if we've reached the last slot in this leaf we need * to go to the next leaf and reset everything */ if (slot >= nritems-1) { ret = btrfs_next_leaf(root, path); if (ret) break; leaf = path->nodes[0]; nritems = btrfs_header_nritems(leaf); slot = path->slots[0]; } else { /* * just walking through the slots on this leaf */ slot++; path->slots[0]++; } } advance = 1; item = btrfs_item_nr(leaf, slot); btrfs_item_key_to_cpu(leaf, &found_key, slot); /* check to make sure this item is what we want */ if (found_key.objectid != key.objectid) break; if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY) break; di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); total_size += btrfs_dir_name_len(leaf, di)+1; /* we are just looking for how big our buffer needs to be */ if (!size) continue; /* find our handler for this xattr */ name_ptr = (unsigned long)(di + 1); handler = find_btrfs_xattr_handler(leaf, name_ptr, btrfs_dir_name_len(leaf, di)); if (!handler) { printk(KERN_ERR "btrfs: unsupported xattr found\n"); continue; } name = kmalloc(btrfs_dir_name_len(leaf, di), GFP_KERNEL); read_extent_buffer(leaf, name, name_ptr, btrfs_dir_name_len(leaf, di)); /* call the list function associated with this xattr */ written = handler->list(inode, buffer, size_left, name, btrfs_dir_name_len(leaf, di)); kfree(name); if (written < 0) { ret = -ERANGE; break; } size_left -= written; buffer += written; } ret = total_size; err: btrfs_free_path(path); return ret; } /* * Handler functions */ #define BTRFS_XATTR_SETGET_FUNCS(name, index) \ static int btrfs_xattr_##name##_get(struct inode *inode, \ const char *name, void *value, \ size_t size) \ { \ if (*name == '\0') \ return -EINVAL; \ return btrfs_xattr_get(inode, index, name, value, size); \ } \ static int btrfs_xattr_##name##_set(struct inode *inode, \ const char *name, const void *value,\ size_t size, int flags) \ { \ if (*name == '\0') \ return -EINVAL; \ return btrfs_xattr_set(inode, index, name, value, size, flags); \ } BTRFS_XATTR_SETGET_FUNCS(security, BTRFS_XATTR_INDEX_SECURITY); BTRFS_XATTR_SETGET_FUNCS(system, BTRFS_XATTR_INDEX_SYSTEM); BTRFS_XATTR_SETGET_FUNCS(user, BTRFS_XATTR_INDEX_USER); BTRFS_XATTR_SETGET_FUNCS(trusted, BTRFS_XATTR_INDEX_TRUSTED); struct xattr_handler btrfs_xattr_security_handler = { .prefix = XATTR_SECURITY_PREFIX, .list = btrfs_xattr_generic_list, .get = btrfs_xattr_security_get, .set = btrfs_xattr_security_set, }; struct xattr_handler btrfs_xattr_system_handler = { .prefix = XATTR_SYSTEM_PREFIX, .list = btrfs_xattr_generic_list, .get = btrfs_xattr_system_get, .set = btrfs_xattr_system_set, }; struct xattr_handler btrfs_xattr_user_handler = { .prefix = XATTR_USER_PREFIX, .list = btrfs_xattr_generic_list, .get = btrfs_xattr_user_get, .set = btrfs_xattr_user_set, }; struct xattr_handler btrfs_xattr_trusted_handler = { .prefix = XATTR_TRUSTED_PREFIX, .list = btrfs_xattr_generic_list, .get = btrfs_xattr_trusted_get, .set = btrfs_xattr_trusted_set, };