fs/btrfs/xattr.c - arm/linux - Git at Google

 /*
  * 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 <linux/security.h>
 #include "ctree.h"
 #include "btrfs_inode.h"
 #include "transaction.h"
 #include "xattr.h"
 #include "disk-io.h"


 ssize_t __btrfs_getxattr(struct inode *inode, const char *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;
 	int ret = 0;
 	unsigned long data_ptr;

 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;

 	/* lookup the xattr by name */
 	di = btrfs_lookup_xattr(NULL, root, path, inode->i_ino, name,
 				strlen(name), 0);
 	if (!di) {
 		ret = -ENODATA;
 		goto out;
 	} else if (IS_ERR(di)) {
 		ret = PTR_ERR(di);
 		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;
 	}

 	/*
 	 * The way things are packed into the leaf is like this
 	 * |struct btrfs_dir_item|name|data|
 	 * where name is the xattr name, so security.foo, and data is the
 	 * content of the xattr.  data_ptr points to the location in memory
 	 * where the data starts in the in memory leaf
 	 */
 	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:
 	btrfs_free_path(path);
 	return ret;
 }

 int __btrfs_setxattr(struct inode *inode, const char *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;
 	int ret = 0, mod = 0;

 	path = btrfs_alloc_path();
 	if (!path)
 		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 {
 		btrfs_release_path(root, path);

 		if (flags & XATTR_REPLACE) {
 			/* we couldn't find the attr to replace */
 			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);
 	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;
 	int ret = 0, slot, advance;
 	size_t total_size = 0, size_left = size;
 	unsigned long name_ptr;
 	size_t name_len;
 	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;
 	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);

 		name_len = btrfs_dir_name_len(leaf, di);
 		total_size += name_len + 1;

 		/* we are just looking for how big our buffer needs to be */
 		if (!size)
 			continue;

 		if (!buffer || (name_len + 1) > size_left) {
 			ret = -ERANGE;
 			goto err;
 		}

 		name_ptr = (unsigned long)(di + 1);
 		read_extent_buffer(leaf, buffer, name_ptr, name_len);
 		buffer[name_len] = '\0';

 		size_left -= name_len + 1;
 		buffer += name_len + 1;
 	}
 	ret = total_size;

 err:
 	btrfs_free_path(path);

 	return ret;
 }

 /*
  * List of handlers for synthetic system.* attributes.  All real ondisk
  * attributes are handled directly.
  */
 struct xattr_handler *btrfs_xattr_handlers[] = {
 #ifdef CONFIG_FS_POSIX_ACL
 	&btrfs_xattr_acl_access_handler,
 	&btrfs_xattr_acl_default_handler,
 #endif
 	NULL,
 };

 /*
  * Check if the attribute is in a supported namespace.
  *
  * This applied after the check for the synthetic attributes in the system
  * namespace.
  */
 static bool btrfs_is_valid_xattr(const char *name)
 {
 	return !strncmp(name, XATTR_SECURITY_PREFIX,
 			XATTR_SECURITY_PREFIX_LEN) ||
 	       !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) ||
 	       !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) ||
 	       !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
 }

 ssize_t btrfs_getxattr(struct dentry *dentry, const char *name,
 		       void *buffer, size_t size)
 {
 	/*
 	 * If this is a request for a synthetic attribute in the system.*
 	 * namespace use the generic infrastructure to resolve a handler
 	 * for it via sb->s_xattr.
 	 */
 	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
 		return generic_getxattr(dentry, name, buffer, size);

 	if (!btrfs_is_valid_xattr(name))
 		return -EOPNOTSUPP;
 	return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
 }

 int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 		   size_t size, int flags)
 {
 	/*
 	 * If this is a request for a synthetic attribute in the system.*
 	 * namespace use the generic infrastructure to resolve a handler
 	 * for it via sb->s_xattr.
 	 */
 	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
 		return generic_setxattr(dentry, name, value, size, flags);

 	if (!btrfs_is_valid_xattr(name))
 		return -EOPNOTSUPP;

 	if (size == 0)
 		value = "";  /* empty EA, do not remove */
 	return __btrfs_setxattr(dentry->d_inode, name, value, size, flags);
 }

 int btrfs_removexattr(struct dentry *dentry, const char *name)
 {
 	/*
 	 * If this is a request for a synthetic attribute in the system.*
 	 * namespace use the generic infrastructure to resolve a handler
 	 * for it via sb->s_xattr.
 	 */
 	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
 		return generic_removexattr(dentry, name);

 	if (!btrfs_is_valid_xattr(name))
 		return -EOPNOTSUPP;
 	return __btrfs_setxattr(dentry->d_inode, name, NULL, 0, XATTR_REPLACE);
 }

 int btrfs_xattr_security_init(struct inode *inode, struct inode *dir)
 {
 	int err;
 	size_t len;
 	void *value;
 	char *suffix;
 	char *name;

 	err = security_inode_init_security(inode, dir, &suffix, &value, &len);
 	if (err) {
 		if (err == -EOPNOTSUPP)
 			return 0;
 		return err;
 	}

 	name = kmalloc(XATTR_SECURITY_PREFIX_LEN + strlen(suffix) + 1,
 		       GFP_NOFS);
 	if (!name) {
 		err = -ENOMEM;
 	} else {
 		strcpy(name, XATTR_SECURITY_PREFIX);
 		strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);
 		err = __btrfs_setxattr(inode, name, value, len, 0);
 		kfree(name);
 	}

 	kfree(suffix);
 	kfree(value);
 	return err;
 }
	/*
	* 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 <linux/security.h>
	#include "ctree.h"
	#include "btrfs_inode.h"
	#include "transaction.h"
	#include "xattr.h"
	#include "disk-io.h"


	ssize_t __btrfs_getxattr(struct inode inode, const char 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;
	int ret = 0;
	unsigned long data_ptr;

	path = btrfs_alloc_path();
	if (!path)
	return -ENOMEM;

	/* lookup the xattr by name */
	di = btrfs_lookup_xattr(NULL, root, path, inode->i_ino, name,
	strlen(name), 0);
	if (!di) {
	ret = -ENODATA;
	goto out;
	} else if (IS_ERR(di)) {
	ret = PTR_ERR(di);
	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;
	}

	/*
	* The way things are packed into the leaf is like this
	* \|struct btrfs_dir_item\|name\|data\|
	* where name is the xattr name, so security.foo, and data is the
	* content of the xattr. data_ptr points to the location in memory
	* where the data starts in the in memory leaf
	*/
	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:
	btrfs_free_path(path);
	return ret;
	}

	int __btrfs_setxattr(struct inode inode, const char 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;
	int ret = 0, mod = 0;

	path = btrfs_alloc_path();
	if (!path)
	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 {
	btrfs_release_path(root, path);

	if (flags & XATTR_REPLACE) {
	/* we couldn't find the attr to replace */
	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);
	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;
	int ret = 0, slot, advance;
	size_t total_size = 0, size_left = size;
	unsigned long name_ptr;
	size_t name_len;
	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;
	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);

	name_len = btrfs_dir_name_len(leaf, di);
	total_size += name_len + 1;

	/* we are just looking for how big our buffer needs to be */
	if (!size)
	continue;

	if (!buffer \|\| (name_len + 1) > size_left) {
	ret = -ERANGE;
	goto err;
	}

	name_ptr = (unsigned long)(di + 1);
	read_extent_buffer(leaf, buffer, name_ptr, name_len);
	buffer[name_len] = '\0';

	size_left -= name_len + 1;
	buffer += name_len + 1;
	}
	ret = total_size;

	err:
	btrfs_free_path(path);

	return ret;
	}

	/*
	* List of handlers for synthetic system.* attributes. All real ondisk
	* attributes are handled directly.
	*/
	struct xattr_handler *btrfs_xattr_handlers[] = {
	#ifdef CONFIG_FS_POSIX_ACL
	&btrfs_xattr_acl_access_handler,
	&btrfs_xattr_acl_default_handler,
	#endif
	NULL,
	};

	/*
	* Check if the attribute is in a supported namespace.
	*
	* This applied after the check for the synthetic attributes in the system
	* namespace.
	*/
	static bool btrfs_is_valid_xattr(const char *name)
	{
	return !strncmp(name, XATTR_SECURITY_PREFIX,
	XATTR_SECURITY_PREFIX_LEN) \|\|
	!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) \|\|
	!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) \|\|
	!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
	}

	ssize_t btrfs_getxattr(struct dentry dentry, const char name,
	void *buffer, size_t size)
	{
	/*
	* If this is a request for a synthetic attribute in the system.*
	* namespace use the generic infrastructure to resolve a handler
	* for it via sb->s_xattr.
	*/
	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	return generic_getxattr(dentry, name, buffer, size);

	if (!btrfs_is_valid_xattr(name))
	return -EOPNOTSUPP;
	return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
	}

	int btrfs_setxattr(struct dentry dentry, const char name, const void *value,
	size_t size, int flags)
	{
	/*
	* If this is a request for a synthetic attribute in the system.*
	* namespace use the generic infrastructure to resolve a handler
	* for it via sb->s_xattr.
	*/
	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	return generic_setxattr(dentry, name, value, size, flags);

	if (!btrfs_is_valid_xattr(name))
	return -EOPNOTSUPP;

	if (size == 0)
	value = ""; /* empty EA, do not remove */
	return __btrfs_setxattr(dentry->d_inode, name, value, size, flags);
	}

	int btrfs_removexattr(struct dentry dentry, const char name)
	{
	/*
	* If this is a request for a synthetic attribute in the system.*
	* namespace use the generic infrastructure to resolve a handler
	* for it via sb->s_xattr.
	*/
	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
	return generic_removexattr(dentry, name);

	if (!btrfs_is_valid_xattr(name))
	return -EOPNOTSUPP;
	return __btrfs_setxattr(dentry->d_inode, name, NULL, 0, XATTR_REPLACE);
	}

	int btrfs_xattr_security_init(struct inode inode, struct inode dir)
	{
	int err;
	size_t len;
	void *value;
	char *suffix;
	char *name;

	err = security_inode_init_security(inode, dir, &suffix, &value, &len);
	if (err) {
	if (err == -EOPNOTSUPP)
	return 0;
	return err;
	}

	name = kmalloc(XATTR_SECURITY_PREFIX_LEN + strlen(suffix) + 1,
	GFP_NOFS);
	if (!name) {
	err = -ENOMEM;
	} else {
	strcpy(name, XATTR_SECURITY_PREFIX);
	strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);
	err = __btrfs_setxattr(inode, name, value, len, 0);
	kfree(name);
	}

	kfree(suffix);
	kfree(value);
	return err;
	}