[net-next-2.6.git] / fs / xattr.c

/*
  File: fs/xattr.c

  Extended attribute handling.

  Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org>
  Copyright (C) 2001 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com>
  Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
 */
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/file.h>
#include <linux/xattr.h>
#include <linux/namei.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/module.h>
#include <asm/uaccess.h>

/*
 * Extended attribute SET operations
 */
static long
setxattr(struct dentry *d, char __user *name, void __user *value,
	 size_t size, int flags)
{
	int error;
	void *kvalue = NULL;
	char kname[XATTR_NAME_MAX + 1];

	if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
		return -EINVAL;

	error = strncpy_from_user(kname, name, sizeof(kname));
	if (error == 0 || error == sizeof(kname))
		error = -ERANGE;
	if (error < 0)
		return error;

	if (size) {
		if (size > XATTR_SIZE_MAX)
			return -E2BIG;
		kvalue = kmalloc(size, GFP_KERNEL);
		if (!kvalue)
			return -ENOMEM;
		if (copy_from_user(kvalue, value, size)) {
			kfree(kvalue);
			return -EFAULT;
		}
	}

	error = -EOPNOTSUPP;
	if (d->d_inode->i_op && d->d_inode->i_op->setxattr) {
		down(&d->d_inode->i_sem);
		error = security_inode_setxattr(d, kname, kvalue, size, flags);
		if (error)
			goto out;
		error = d->d_inode->i_op->setxattr(d, kname, kvalue, size, flags);
		if (!error)
			security_inode_post_setxattr(d, kname, kvalue, size, flags);
out:
		up(&d->d_inode->i_sem);
	}
	if (kvalue)
		kfree(kvalue);
	return error;
}

asmlinkage long
sys_setxattr(char __user *path, char __user *name, void __user *value,
	     size_t size, int flags)
{
	struct nameidata nd;
	int error;

	error = user_path_walk(path, &nd);
	if (error)
		return error;
	error = setxattr(nd.dentry, name, value, size, flags);
	path_release(&nd);
	return error;
}

asmlinkage long
sys_lsetxattr(char __user *path, char __user *name, void __user *value,
	      size_t size, int flags)
{
	struct nameidata nd;
	int error;

	error = user_path_walk_link(path, &nd);
	if (error)
		return error;
	error = setxattr(nd.dentry, name, value, size, flags);
	path_release(&nd);
	return error;
}

asmlinkage long
sys_fsetxattr(int fd, char __user *name, void __user *value,
	      size_t size, int flags)
{
	struct file *f;
	int error = -EBADF;

	f = fget(fd);
	if (!f)
		return error;
	error = setxattr(f->f_dentry, name, value, size, flags);
	fput(f);
	return error;
}

/*
 * Extended attribute GET operations
 */
static ssize_t
getxattr(struct dentry *d, char __user *name, void __user *value, size_t size)
{
	ssize_t error;
	void *kvalue = NULL;
	char kname[XATTR_NAME_MAX + 1];

	error = strncpy_from_user(kname, name, sizeof(kname));
	if (error == 0 || error == sizeof(kname))
		error = -ERANGE;
	if (error < 0)
		return error;

	if (size) {
		if (size > XATTR_SIZE_MAX)
			size = XATTR_SIZE_MAX;
		kvalue = kmalloc(size, GFP_KERNEL);
		if (!kvalue)
			return -ENOMEM;
	}

	error = -EOPNOTSUPP;
	if (d->d_inode->i_op && d->d_inode->i_op->getxattr) {
		error = security_inode_getxattr(d, kname);
		if (error)
			goto out;
		error = d->d_inode->i_op->getxattr(d, kname, kvalue, size);
		if (error > 0) {
			if (size && copy_to_user(value, kvalue, error))
				error = -EFAULT;
		} else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
			/* The file system tried to returned a value bigger
			   than XATTR_SIZE_MAX bytes. Not possible. */
			error = -E2BIG;
		}
	}
out:
	if (kvalue)
		kfree(kvalue);
	return error;
}

asmlinkage ssize_t
sys_getxattr(char __user *path, char __user *name, void __user *value,
	     size_t size)
{
	struct nameidata nd;
	ssize_t error;

	error = user_path_walk(path, &nd);
	if (error)
		return error;
	error = getxattr(nd.dentry, name, value, size);
	path_release(&nd);
	return error;
}

asmlinkage ssize_t
sys_lgetxattr(char __user *path, char __user *name, void __user *value,
	      size_t size)
{
	struct nameidata nd;
	ssize_t error;

	error = user_path_walk_link(path, &nd);
	if (error)
		return error;
	error = getxattr(nd.dentry, name, value, size);
	path_release(&nd);
	return error;
}

asmlinkage ssize_t
sys_fgetxattr(int fd, char __user *name, void __user *value, size_t size)
{
	struct file *f;
	ssize_t error = -EBADF;

	f = fget(fd);
	if (!f)
		return error;
	error = getxattr(f->f_dentry, name, value, size);
	fput(f);
	return error;
}

/*
 * Extended attribute LIST operations
 */
static ssize_t
listxattr(struct dentry *d, char __user *list, size_t size)
{
	ssize_t error;
	char *klist = NULL;

	if (size) {
		if (size > XATTR_LIST_MAX)
			size = XATTR_LIST_MAX;
		klist = kmalloc(size, GFP_KERNEL);
		if (!klist)
			return -ENOMEM;
	}

	error = -EOPNOTSUPP;
	if (d->d_inode->i_op && d->d_inode->i_op->listxattr) {
		error = security_inode_listxattr(d);
		if (error)
			goto out;
		error = d->d_inode->i_op->listxattr(d, klist, size);
		if (error > 0) {
			if (size && copy_to_user(list, klist, error))
				error = -EFAULT;
		} else if (error == -ERANGE && size >= XATTR_LIST_MAX) {
			/* The file system tried to returned a list bigger
			   than XATTR_LIST_MAX bytes. Not possible. */
			error = -E2BIG;
		}
	}
out:
	if (klist)
		kfree(klist);
	return error;
}

asmlinkage ssize_t
sys_listxattr(char __user *path, char __user *list, size_t size)
{
	struct nameidata nd;
	ssize_t error;

	error = user_path_walk(path, &nd);
	if (error)
		return error;
	error = listxattr(nd.dentry, list, size);
	path_release(&nd);
	return error;
}

asmlinkage ssize_t
sys_llistxattr(char __user *path, char __user *list, size_t size)
{
	struct nameidata nd;
	ssize_t error;

	error = user_path_walk_link(path, &nd);
	if (error)
		return error;
	error = listxattr(nd.dentry, list, size);
	path_release(&nd);
	return error;
}

asmlinkage ssize_t
sys_flistxattr(int fd, char __user *list, size_t size)
{
	struct file *f;
	ssize_t error = -EBADF;

	f = fget(fd);
	if (!f)
		return error;
	error = listxattr(f->f_dentry, list, size);
	fput(f);
	return error;
}

/*
 * Extended attribute REMOVE operations
 */
static long
removexattr(struct dentry *d, char __user *name)
{
	int error;
	char kname[XATTR_NAME_MAX + 1];

	error = strncpy_from_user(kname, name, sizeof(kname));
	if (error == 0 || error == sizeof(kname))
		error = -ERANGE;
	if (error < 0)
		return error;

	error = -EOPNOTSUPP;
	if (d->d_inode->i_op && d->d_inode->i_op->removexattr) {
		error = security_inode_removexattr(d, kname);
		if (error)
			goto out;
		down(&d->d_inode->i_sem);
		error = d->d_inode->i_op->removexattr(d, kname);
		up(&d->d_inode->i_sem);
	}
out:
	return error;
}

asmlinkage long
sys_removexattr(char __user *path, char __user *name)
{
	struct nameidata nd;
	int error;

	error = user_path_walk(path, &nd);
	if (error)
		return error;
	error = removexattr(nd.dentry, name);
	path_release(&nd);
	return error;
}

asmlinkage long
sys_lremovexattr(char __user *path, char __user *name)
{
	struct nameidata nd;
	int error;

	error = user_path_walk_link(path, &nd);
	if (error)
		return error;
	error = removexattr(nd.dentry, name);
	path_release(&nd);
	return error;
}

asmlinkage long
sys_fremovexattr(int fd, char __user *name)
{
	struct file *f;
	int error = -EBADF;

	f = fget(fd);
	if (!f)
		return error;
	error = removexattr(f->f_dentry, name);
	fput(f);
	return error;
}


static const char *
strcmp_prefix(const char *a, const char *a_prefix)
{
	while (*a_prefix && *a == *a_prefix) {
		a++;
		a_prefix++;
	}
	return *a_prefix ? NULL : a;
}

/*
 * In order to implement different sets of xattr operations for each xattr
 * prefix with the generic xattr API, a filesystem should create a
 * null-terminated array of struct xattr_handler (one for each prefix) and
 * hang a pointer to it off of the s_xattr field of the superblock.
 *
 * The generic_fooxattr() functions will use this list to dispatch xattr
 * operations to the correct xattr_handler.
 */
#define for_each_xattr_handler(handlers, handler)		\
		for ((handler) = *(handlers)++;			\
			(handler) != NULL;			\
			(handler) = *(handlers)++)

/*
 * Find the xattr_handler with the matching prefix.
 */
static struct xattr_handler *
xattr_resolve_name(struct xattr_handler **handlers, const char **name)
{
	struct xattr_handler *handler;

	if (!*name)
		return NULL;

	for_each_xattr_handler(handlers, handler) {
		const char *n = strcmp_prefix(*name, handler->prefix);
		if (n) {
			*name = n;
			break;
		}
	}
	return handler;
}

/*
 * Find the handler for the prefix and dispatch its get() operation.
 */
ssize_t
generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size)
{
	struct xattr_handler *handler;
	struct inode *inode = dentry->d_inode;

	handler = xattr_resolve_name(inode->i_sb->s_xattr, &name);
	if (!handler)
		return -EOPNOTSUPP;
	return handler->get(inode, name, buffer, size);
}

/*
 * Combine the results of the list() operation from every xattr_handler in the
 * list.
 */
ssize_t
generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
{
	struct inode *inode = dentry->d_inode;
	struct xattr_handler *handler, **handlers = inode->i_sb->s_xattr;
	unsigned int size = 0;

	if (!buffer) {
		for_each_xattr_handler(handlers, handler)
			size += handler->list(inode, NULL, 0, NULL, 0);
	} else {
		char *buf = buffer;

		for_each_xattr_handler(handlers, handler) {
			size = handler->list(inode, buf, buffer_size, NULL, 0);
			if (size > buffer_size)
				return -ERANGE;
			buf += size;
			buffer_size -= size;
		}
		size = buf - buffer;
	}
	return size;
}

/*
 * Find the handler for the prefix and dispatch its set() operation.
 */
int
generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags)
{
	struct xattr_handler *handler;
	struct inode *inode = dentry->d_inode;

	if (size == 0)
		value = "";  /* empty EA, do not remove */
	handler = xattr_resolve_name(inode->i_sb->s_xattr, &name);
	if (!handler)
		return -EOPNOTSUPP;
	return handler->set(inode, name, value, size, flags);
}

/*
 * Find the handler for the prefix and dispatch its set() operation to remove
 * any associated extended attribute.
 */
int
generic_removexattr(struct dentry *dentry, const char *name)
{
	struct xattr_handler *handler;
	struct inode *inode = dentry->d_inode;

	handler = xattr_resolve_name(inode->i_sb->s_xattr, &name);
	if (!handler)
		return -EOPNOTSUPP;
	return handler->set(inode, name, NULL, 0, XATTR_REPLACE);
}

EXPORT_SYMBOL(generic_getxattr);
EXPORT_SYMBOL(generic_listxattr);
EXPORT_SYMBOL(generic_setxattr);
EXPORT_SYMBOL(generic_removexattr);
Commit	Line	Data
1da177e4 LT	1	/*
	2	File: fs/xattr.c
	3
	4	Extended attribute handling.
	5
	6	Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org>
	7	Copyright (C) 2001 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com>
	8	Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
	9	*/
	10	#include <linux/fs.h>
	11	#include <linux/slab.h>
	12	#include <linux/smp_lock.h>
	13	#include <linux/file.h>
	14	#include <linux/xattr.h>
	15	#include <linux/namei.h>
	16	#include <linux/security.h>
	17	#include <linux/syscalls.h>
	18	#include <linux/module.h>
	19	#include <asm/uaccess.h>
	20
	21	/*
	22	* Extended attribute SET operations
	23	*/
	24	static long
	25	setxattr(struct dentry d, char __user name, void __user *value,
	26	size_t size, int flags)
	27	{
	28	int error;
	29	void *kvalue = NULL;
	30	char kname[XATTR_NAME_MAX + 1];
	31
	32	if (flags & ~(XATTR_CREATE\|XATTR_REPLACE))
	33	return -EINVAL;
	34
	35	error = strncpy_from_user(kname, name, sizeof(kname));
	36	if (error == 0 \|\| error == sizeof(kname))
	37	error = -ERANGE;
	38	if (error < 0)
	39	return error;
	40
	41	if (size) {
	42	if (size > XATTR_SIZE_MAX)
	43	return -E2BIG;
	44	kvalue = kmalloc(size, GFP_KERNEL);
	45	if (!kvalue)
	46	return -ENOMEM;
	47	if (copy_from_user(kvalue, value, size)) {
	48	kfree(kvalue);
	49	return -EFAULT;
	50	}
	51	}
	52
	53	error = -EOPNOTSUPP;
	54	if (d->d_inode->i_op && d->d_inode->i_op->setxattr) {
	55	down(&d->d_inode->i_sem);
	56	error = security_inode_setxattr(d, kname, kvalue, size, flags);
	57	if (error)
	58	goto out;
	59	error = d->d_inode->i_op->setxattr(d, kname, kvalue, size, flags);
	60	if (!error)
	61	security_inode_post_setxattr(d, kname, kvalue, size, flags);
	62	out:
	63	up(&d->d_inode->i_sem);
	64	}
65	if (kvalue)
66	kfree(kvalue);
67	return error;
68	}
69
70	asmlinkage long
71	sys_setxattr(char __user path, char __user name, void __user *value,
72	size_t size, int flags)
73	{
74	struct nameidata nd;
75	int error;
76
77	error = user_path_walk(path, &nd);
78	if (error)
79	return error;
80	error = setxattr(nd.dentry, name, value, size, flags);
81	path_release(&nd);
82	return error;
83	}
84
85	asmlinkage long
86	sys_lsetxattr(char __user path, char __user name, void __user *value,
87	size_t size, int flags)
88	{
89	struct nameidata nd;
90	int error;
91
92	error = user_path_walk_link(path, &nd);
93	if (error)
94	return error;
95	error = setxattr(nd.dentry, name, value, size, flags);
96	path_release(&nd);
97	return error;
98	}
99
100	asmlinkage long
101	sys_fsetxattr(int fd, char __user name, void __user value,
102	size_t size, int flags)
103	{
104	struct file *f;
105	int error = -EBADF;
106
107	f = fget(fd);
108	if (!f)
109	return error;
110	error = setxattr(f->f_dentry, name, value, size, flags);
111	fput(f);
112	return error;
113	}
114
115	/*
116	* Extended attribute GET operations
117	*/
118	static ssize_t
119	getxattr(struct dentry d, char __user name, void __user *value, size_t size)
120	{
121	ssize_t error;
122	void *kvalue = NULL;
123	char kname[XATTR_NAME_MAX + 1];
124
125	error = strncpy_from_user(kname, name, sizeof(kname));
126	if (error == 0 \|\| error == sizeof(kname))
127	error = -ERANGE;
128	if (error < 0)
129	return error;
130
131	if (size) {
132	if (size > XATTR_SIZE_MAX)
133	size = XATTR_SIZE_MAX;
134	kvalue = kmalloc(size, GFP_KERNEL);
135	if (!kvalue)
136	return -ENOMEM;
137	}
138
139	error = -EOPNOTSUPP;
140	if (d->d_inode->i_op && d->d_inode->i_op->getxattr) {
141	error = security_inode_getxattr(d, kname);
142	if (error)
143	goto out;
144	error = d->d_inode->i_op->getxattr(d, kname, kvalue, size);
145	if (error > 0) {
146	if (size && copy_to_user(value, kvalue, error))
147	error = -EFAULT;
148	} else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
149	/* The file system tried to returned a value bigger
150	than XATTR_SIZE_MAX bytes. Not possible. */
151	error = -E2BIG;
152	}
153	}
154	out:
155	if (kvalue)
156	kfree(kvalue);
157	return error;
158	}
159
160	asmlinkage ssize_t
161	sys_getxattr(char __user path, char __user name, void __user *value,
162	size_t size)
163	{
164	struct nameidata nd;
165	ssize_t error;
166
167	error = user_path_walk(path, &nd);
168	if (error)
169	return error;
170	error = getxattr(nd.dentry, name, value, size);
171	path_release(&nd);
172	return error;
173	}
174
175	asmlinkage ssize_t
176	sys_lgetxattr(char __user path, char __user name, void __user *value,
177	size_t size)
178	{
179	struct nameidata nd;
180	ssize_t error;
181
182	error = user_path_walk_link(path, &nd);
183	if (error)
184	return error;
185	error = getxattr(nd.dentry, name, value, size);
186	path_release(&nd);
187	return error;
188	}
189
190	asmlinkage ssize_t
191	sys_fgetxattr(int fd, char __user name, void __user value, size_t size)
192	{
193	struct file *f;
194	ssize_t error = -EBADF;
195
196	f = fget(fd);
197	if (!f)
198	return error;
199	error = getxattr(f->f_dentry, name, value, size);
200	fput(f);
201	return error;
202	}
203
204	/*
205	* Extended attribute LIST operations
206	*/
207	static ssize_t
208	listxattr(struct dentry d, char __user list, size_t size)
209	{
210	ssize_t error;
211	char *klist = NULL;
212
213	if (size) {
214	if (size > XATTR_LIST_MAX)
215	size = XATTR_LIST_MAX;
216	klist = kmalloc(size, GFP_KERNEL);
217	if (!klist)
218	return -ENOMEM;
219	}
220
221	error = -EOPNOTSUPP;
222	if (d->d_inode->i_op && d->d_inode->i_op->listxattr) {
223	error = security_inode_listxattr(d);
224	if (error)
225	goto out;
226	error = d->d_inode->i_op->listxattr(d, klist, size);
227	if (error > 0) {
228	if (size && copy_to_user(list, klist, error))
229	error = -EFAULT;
230	} else if (error == -ERANGE && size >= XATTR_LIST_MAX) {
231	/* The file system tried to returned a list bigger
232	than XATTR_LIST_MAX bytes. Not possible. */
233	error = -E2BIG;
234	}
235	}
236	out:
237	if (klist)
238	kfree(klist);
239	return error;
240	}
241
242	asmlinkage ssize_t
243	sys_listxattr(char __user path, char __user list, size_t size)
244	{
245	struct nameidata nd;
246	ssize_t error;
247
248	error = user_path_walk(path, &nd);
249	if (error)
250	return error;
251	error = listxattr(nd.dentry, list, size);
252	path_release(&nd);
253	return error;
254	}
255
256	asmlinkage ssize_t
257	sys_llistxattr(char __user path, char __user list, size_t size)
258	{
259	struct nameidata nd;
260	ssize_t error;
261
262	error = user_path_walk_link(path, &nd);
263	if (error)
264	return error;
265	error = listxattr(nd.dentry, list, size);
266	path_release(&nd);
267	return error;
268	}
269
270	asmlinkage ssize_t
271	sys_flistxattr(int fd, char __user *list, size_t size)
272	{
273	struct file *f;
274	ssize_t error = -EBADF;
275
276	f = fget(fd);
277	if (!f)
278	return error;
279	error = listxattr(f->f_dentry, list, size);
280	fput(f);
281	return error;
282	}
283
284	/*
285	* Extended attribute REMOVE operations
286	*/
287	static long
288	removexattr(struct dentry d, char __user name)
289	{
290	int error;
291	char kname[XATTR_NAME_MAX + 1];
292
293	error = strncpy_from_user(kname, name, sizeof(kname));
294	if (error == 0 \|\| error == sizeof(kname))
295	error = -ERANGE;
296	if (error < 0)
297	return error;
298
299	error = -EOPNOTSUPP;
300	if (d->d_inode->i_op && d->d_inode->i_op->removexattr) {
301	error = security_inode_removexattr(d, kname);
302	if (error)
303	goto out;
304	down(&d->d_inode->i_sem);
305	error = d->d_inode->i_op->removexattr(d, kname);
306	up(&d->d_inode->i_sem);
307	}
308	out:
309	return error;
310	}
311
312	asmlinkage long
313	sys_removexattr(char __user path, char __user name)
314	{
315	struct nameidata nd;
316	int error;
317
318	error = user_path_walk(path, &nd);
319	if (error)
320	return error;
321	error = removexattr(nd.dentry, name);
322	path_release(&nd);
323	return error;
324	}
325
326	asmlinkage long
327	sys_lremovexattr(char __user path, char __user name)
328	{
329	struct nameidata nd;
330	int error;
331
332	error = user_path_walk_link(path, &nd);
333	if (error)
334	return error;
335	error = removexattr(nd.dentry, name);
336	path_release(&nd);
337	return error;
338	}
339
340	asmlinkage long
341	sys_fremovexattr(int fd, char __user *name)
342	{
343	struct file *f;
344	int error = -EBADF;
345
346	f = fget(fd);
347	if (!f)
348	return error;
349	error = removexattr(f->f_dentry, name);
350	fput(f);
351	return error;
352	}
353
354
355	static const char *
356	strcmp_prefix(const char a, const char a_prefix)
357	{
358	while (a_prefix && a == *a_prefix) {
359	a++;
360	a_prefix++;
361	}
362	return *a_prefix ? NULL : a;
363	}
364
365	/*
366	* In order to implement different sets of xattr operations for each xattr
367	* prefix with the generic xattr API, a filesystem should create a
368	* null-terminated array of struct xattr_handler (one for each prefix) and
369	* hang a pointer to it off of the s_xattr field of the superblock.
370	*
371	* The generic_fooxattr() functions will use this list to dispatch xattr
372	* operations to the correct xattr_handler.
373	*/
374	#define for_each_xattr_handler(handlers, handler) \
375	for ((handler) = *(handlers)++; \
376	(handler) != NULL; \
377	(handler) = *(handlers)++)
378
379	/*
380	* Find the xattr_handler with the matching prefix.
381	*/
382	static struct xattr_handler *
383	xattr_resolve_name(struct xattr_handler handlers, const char name)
384	{
385	struct xattr_handler *handler;
386
387	if (!*name)
388	return NULL;
389
390	for_each_xattr_handler(handlers, handler) {
391	const char n = strcmp_prefix(name, handler->prefix);
392	if (n) {
393	*name = n;
394	break;
395	}
396	}
397	return handler;
398	}
399
400	/*
401	* Find the handler for the prefix and dispatch its get() operation.
402	*/
403	ssize_t
404	generic_getxattr(struct dentry dentry, const char name, void *buffer, size_t size)
405	{
406	struct xattr_handler *handler;
407	struct inode *inode = dentry->d_inode;
408
409	handler = xattr_resolve_name(inode->i_sb->s_xattr, &name);
410	if (!handler)
411	return -EOPNOTSUPP;
412	return handler->get(inode, name, buffer, size);
413	}
414
415	/*
416	* Combine the results of the list() operation from every xattr_handler in the
417	* list.
418	*/
419	ssize_t
420	generic_listxattr(struct dentry dentry, char buffer, size_t buffer_size)
421	{
422	struct inode *inode = dentry->d_inode;
423	struct xattr_handler handler, *handlers = inode->i_sb->s_xattr;
424	unsigned int size = 0;
425
426	if (!buffer) {
427	for_each_xattr_handler(handlers, handler)
428	size += handler->list(inode, NULL, 0, NULL, 0);
429	} else {
430	char *buf = buffer;
431
432	for_each_xattr_handler(handlers, handler) {
433	size = handler->list(inode, buf, buffer_size, NULL, 0);
434	if (size > buffer_size)
435	return -ERANGE;
436	buf += size;
437	buffer_size -= size;
438	}
439	size = buf - buffer;
440	}
441	return size;
442	}
443
444	/*
445	* Find the handler for the prefix and dispatch its set() operation.
446	*/
447	int
448	generic_setxattr(struct dentry dentry, const char name, const void *value, size_t size, int flags)
449	{
450	struct xattr_handler *handler;
451	struct inode *inode = dentry->d_inode;
452
453	if (size == 0)
454	value = ""; /* empty EA, do not remove */
455	handler = xattr_resolve_name(inode->i_sb->s_xattr, &name);
456	if (!handler)
457	return -EOPNOTSUPP;
458	return handler->set(inode, name, value, size, flags);
459	}
460
461	/*
462	* Find the handler for the prefix and dispatch its set() operation to remove
463	* any associated extended attribute.
464	*/
465	int
466	generic_removexattr(struct dentry dentry, const char name)
467	{
468	struct xattr_handler *handler;
469	struct inode *inode = dentry->d_inode;
470
471	handler = xattr_resolve_name(inode->i_sb->s_xattr, &name);
472	if (!handler)
473	return -EOPNOTSUPP;
474	return handler->set(inode, name, NULL, 0, XATTR_REPLACE);
475	}
476
477	EXPORT_SYMBOL(generic_getxattr);
478	EXPORT_SYMBOL(generic_listxattr);
479	EXPORT_SYMBOL(generic_setxattr);
480	EXPORT_SYMBOL(generic_removexattr);