1/*
2 * Copyright IBM Corporation, 2010
3 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of version 2.1 of the GNU Lesser General Public License
7 * as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it would be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
12 *
13 */
14
15#include <linux/module.h>
16#include <linux/fs.h>
17#include <linux/sched.h>
18#include <linux/uio.h>
19#include <net/9p/9p.h>
20#include <net/9p/client.h>
21
22#include "fid.h"
23#include "xattr.h"
24
25ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name,
26			   void *buffer, size_t buffer_size)
27{
28	ssize_t retval;
29	u64 attr_size;
30	struct p9_fid *attr_fid;
31	struct kvec kvec = {.iov_base = buffer, .iov_len = buffer_size};
32	struct iov_iter to;
33	int err;
34
35	iov_iter_kvec(&to, READ | ITER_KVEC, &kvec, 1, buffer_size);
36
37	attr_fid = p9_client_xattrwalk(fid, name, &attr_size);
38	if (IS_ERR(attr_fid)) {
39		retval = PTR_ERR(attr_fid);
40		p9_debug(P9_DEBUG_VFS, "p9_client_attrwalk failed %zd\n",
41			 retval);
42		return retval;
43	}
44	if (attr_size > buffer_size) {
45		if (!buffer_size) /* request to get the attr_size */
46			retval = attr_size;
47		else
48			retval = -ERANGE;
49	} else {
50		iov_iter_truncate(&to, attr_size);
51		retval = p9_client_read(attr_fid, 0, &to, &err);
52		if (err)
53			retval = err;
54	}
55	p9_client_clunk(attr_fid);
56	return retval;
57}
58
59
60/*
61 * v9fs_xattr_get()
62 *
63 * Copy an extended attribute into the buffer
64 * provided, or compute the buffer size required.
65 * Buffer is NULL to compute the size of the buffer required.
66 *
67 * Returns a negative error number on failure, or the number of bytes
68 * used / required on success.
69 */
70ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name,
71		       void *buffer, size_t buffer_size)
72{
73	struct p9_fid *fid;
74
75	p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu\n",
76		 name, buffer_size);
77	fid = v9fs_fid_lookup(dentry);
78	if (IS_ERR(fid))
79		return PTR_ERR(fid);
80
81	return v9fs_fid_xattr_get(fid, name, buffer, buffer_size);
82}
83
84/*
85 * v9fs_xattr_set()
86 *
87 * Create, replace or remove an extended attribute for this inode. Buffer
88 * is NULL to remove an existing extended attribute, and non-NULL to
89 * either replace an existing extended attribute, or create a new extended
90 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
91 * specify that an extended attribute must exist and must not exist
92 * previous to the call, respectively.
93 *
94 * Returns 0, or a negative error number on failure.
95 */
96int v9fs_xattr_set(struct dentry *dentry, const char *name,
97		   const void *value, size_t value_len, int flags)
98{
99	struct p9_fid *fid = v9fs_fid_lookup(dentry);
100	if (IS_ERR(fid))
101		return PTR_ERR(fid);
102	return v9fs_fid_xattr_set(fid, name, value, value_len, flags);
103}
104
105int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name,
106		   const void *value, size_t value_len, int flags)
107{
108	struct kvec kvec = {.iov_base = (void *)value, .iov_len = value_len};
109	struct iov_iter from;
110	int retval;
111
112	iov_iter_kvec(&from, WRITE | ITER_KVEC, &kvec, 1, value_len);
113
114	p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu flags = %d\n",
115		 name, value_len, flags);
116
117	/* Clone it */
118	fid = p9_client_walk(fid, 0, NULL, 1);
119	if (IS_ERR(fid))
120		return PTR_ERR(fid);
121
122	/*
123	 * On success fid points to xattr
124	 */
125	retval = p9_client_xattrcreate(fid, name, value_len, flags);
126	if (retval < 0)
127		p9_debug(P9_DEBUG_VFS, "p9_client_xattrcreate failed %d\n",
128			 retval);
129	else
130		p9_client_write(fid, 0, &from, &retval);
131	p9_client_clunk(fid);
132	return retval;
133}
134
135ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
136{
137	return v9fs_xattr_get(dentry, NULL, buffer, buffer_size);
138}
139
140static int v9fs_xattr_handler_get(const struct xattr_handler *handler,
141				  struct dentry *dentry, const char *name,
142				  void *buffer, size_t size)
143{
144	const char *full_name = xattr_full_name(handler, name);
145
146	if (strcmp(name, "") == 0)
147		return -EINVAL;
148	return v9fs_xattr_get(dentry, full_name, buffer, size);
149}
150
151static int v9fs_xattr_handler_set(const struct xattr_handler *handler,
152				  struct dentry *dentry, const char *name,
153				  const void *value, size_t size, int flags)
154{
155	const char *full_name = xattr_full_name(handler, name);
156
157	if (strcmp(name, "") == 0)
158		return -EINVAL;
159	return v9fs_xattr_set(dentry, full_name, value, size, flags);
160}
161
162static struct xattr_handler v9fs_xattr_user_handler = {
163	.prefix	= XATTR_USER_PREFIX,
164	.get	= v9fs_xattr_handler_get,
165	.set	= v9fs_xattr_handler_set,
166};
167
168static struct xattr_handler v9fs_xattr_trusted_handler = {
169	.prefix	= XATTR_TRUSTED_PREFIX,
170	.get	= v9fs_xattr_handler_get,
171	.set	= v9fs_xattr_handler_set,
172};
173
174#ifdef CONFIG_9P_FS_SECURITY
175static struct xattr_handler v9fs_xattr_security_handler = {
176	.prefix	= XATTR_SECURITY_PREFIX,
177	.get	= v9fs_xattr_handler_get,
178	.set	= v9fs_xattr_handler_set,
179};
180#endif
181
182const struct xattr_handler *v9fs_xattr_handlers[] = {
183	&v9fs_xattr_user_handler,
184	&v9fs_xattr_trusted_handler,
185#ifdef CONFIG_9P_FS_POSIX_ACL
186	&v9fs_xattr_acl_access_handler,
187	&v9fs_xattr_acl_default_handler,
188#endif
189#ifdef CONFIG_9P_FS_SECURITY
190	&v9fs_xattr_security_handler,
191#endif
192	NULL
193};
194