1 // SPDX-License-Identifier: LGPL-2.1
2 /*
3 * Copyright IBM Corporation, 2010
4 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
5 */
6
7 #include <linux/module.h>
8 #include <linux/fs.h>
9 #include <linux/sched.h>
10 #include <linux/uio.h>
11 #include <linux/posix_acl_xattr.h>
12 #include <net/9p/9p.h>
13 #include <net/9p/client.h>
14
15 #include "fid.h"
16 #include "xattr.h"
17
18 ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name,
19 void *buffer, size_t buffer_size)
20 {
21 ssize_t retval;
22 u64 attr_size;
23 struct p9_fid *attr_fid;
24 struct kvec kvec = {.iov_base = buffer, .iov_len = buffer_size};
25 struct iov_iter to;
26 int err;
27
28 iov_iter_kvec(&to, ITER_DEST, &kvec, 1, buffer_size);
29
30 attr_fid = p9_client_xattrwalk(fid, name, &attr_size);
31 if (IS_ERR(attr_fid)) {
32 retval = PTR_ERR(attr_fid);
33 p9_debug(P9_DEBUG_VFS, "p9_client_attrwalk failed %zd\n",
34 retval);
35 return retval;
36 }
37 if (attr_size > buffer_size) {
38 if (buffer_size)
39 retval = -ERANGE;
40 else if (attr_size > SSIZE_MAX)
41 retval = -EOVERFLOW;
42 else /* request to get the attr_size */
43 retval = attr_size;
44 } else {
45 iov_iter_truncate(&to, attr_size);
46 retval = p9_client_read(attr_fid, 0, &to, &err);
47 if (err)
48 retval = err;
49 }
50 p9_fid_put(attr_fid);
51 return retval;
52 }
53
54
55 /*
56 * v9fs_xattr_get()
57 *
58 * Copy an extended attribute into the buffer
59 * provided, or compute the buffer size required.
60 * Buffer is NULL to compute the size of the buffer required.
61 *
62 * Returns a negative error number on failure, or the number of bytes
63 * used / required on success.
64 */
65 ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name,
66 void *buffer, size_t buffer_size)
67 {
68 struct p9_fid *fid;
69 int ret;
70
71 p9_debug(P9_DEBUG_VFS, "name = '%s' value_len = %zu\n",
72 name, buffer_size);
73 fid = v9fs_fid_lookup(dentry);
74 if (IS_ERR(fid))
75 return PTR_ERR(fid);
76 ret = v9fs_fid_xattr_get(fid, name, buffer, buffer_size);
77 p9_fid_put(fid);
78
79 return ret;
80 }
81
82 /*
83 * v9fs_xattr_set()
84 *
85 * Create, replace or remove an extended attribute for this inode. Buffer
86 * is NULL to remove an existing extended attribute, and non-NULL to
87 * either replace an existing extended attribute, or create a new extended
88 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
89 * specify that an extended attribute must exist and must not exist
90 * previous to the call, respectively.
91 *
92 * Returns 0, or a negative error number on failure.
93 */
94 int v9fs_xattr_set(struct dentry *dentry, const char *name,
95 const void *value, size_t value_len, int flags)
96 {
97 int ret;
98 struct p9_fid *fid;
99
100 fid = v9fs_fid_lookup(dentry);
101 if (IS_ERR(fid))
102 return PTR_ERR(fid);
103 ret = v9fs_fid_xattr_set(fid, name, value, value_len, flags);
104 p9_fid_put(fid);
105 return ret;
106 }
107
108 int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name,
109 const void *value, size_t value_len, int flags)
110 {
111 struct kvec kvec = {.iov_base = (void *)value, .iov_len = value_len};
112 struct iov_iter from;
113 int retval, err;
114
115 iov_iter_kvec(&from, ITER_SOURCE, &kvec, 1, value_len);
116
117 p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu flags = %d\n",
118 name, value_len, flags);
119
120 /* Clone it */
121 fid = clone_fid(fid);
122 if (IS_ERR(fid))
123 return PTR_ERR(fid);
124
125 /*
126 * On success fid points to xattr
127 */
128 retval = p9_client_xattrcreate(fid, name, value_len, flags);
129 if (retval < 0)
130 p9_debug(P9_DEBUG_VFS, "p9_client_xattrcreate failed %d\n",
131 retval);
132 else
133 p9_client_write(fid, 0, &from, &retval);
134 err = p9_fid_put(fid);
135 if (!retval && err)
136 retval = err;
137 return retval;
138 }
139
140 ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
141 {
142 /* Txattrwalk with an empty string lists xattrs instead */
143 return v9fs_xattr_get(dentry, "", buffer, buffer_size);
144 }
145
146 static int v9fs_xattr_handler_get(const struct xattr_handler *handler,
147 struct dentry *dentry, struct inode *inode,
148 const char *name, void *buffer, size_t size)
149 {
150 const char *full_name = xattr_full_name(handler, name);
151
152 return v9fs_xattr_get(dentry, full_name, buffer, size);
153 }
154
155 static int v9fs_xattr_handler_set(const struct xattr_handler *handler,
156 struct mnt_idmap *idmap,
157 struct dentry *dentry, struct inode *inode,
158 const char *name, const void *value,
159 size_t size, int flags)
160 {
161 const char *full_name = xattr_full_name(handler, name);
162
163 return v9fs_xattr_set(dentry, full_name, value, size, flags);
164 }
165
166 static const struct xattr_handler v9fs_xattr_user_handler = {
167 .prefix = XATTR_USER_PREFIX,
168 .get = v9fs_xattr_handler_get,
169 .set = v9fs_xattr_handler_set,
170 };
171
172 static const struct xattr_handler v9fs_xattr_trusted_handler = {
173 .prefix = XATTR_TRUSTED_PREFIX,
174 .get = v9fs_xattr_handler_get,
175 .set = v9fs_xattr_handler_set,
176 };
177
178 #ifdef CONFIG_9P_FS_SECURITY
179 static const struct xattr_handler v9fs_xattr_security_handler = {
180 .prefix = XATTR_SECURITY_PREFIX,
181 .get = v9fs_xattr_handler_get,
182 .set = v9fs_xattr_handler_set,
183 };
184 #endif
185
186 const struct xattr_handler * const v9fs_xattr_handlers[] = {
187 &v9fs_xattr_user_handler,
188 &v9fs_xattr_trusted_handler,
189 #ifdef CONFIG_9P_FS_SECURITY
190 &v9fs_xattr_security_handler,
191 #endif
192 NULL
193 };
194
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