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 <net/9p/9p.h>
12 #include <net/9p/client.h>
13
14 #include "fid.h"
15 #include "xattr.h"
16
v9fs_fid_xattr_get(struct p9_fid * fid,const char * name,void * buffer,size_t buffer_size)17 ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name,
18 void *buffer, size_t buffer_size)
19 {
20 ssize_t retval;
21 u64 attr_size;
22 struct p9_fid *attr_fid;
23 struct kvec kvec = {.iov_base = buffer, .iov_len = buffer_size};
24 struct iov_iter to;
25 int err;
26
27 iov_iter_kvec(&to, READ, &kvec, 1, buffer_size);
28
29 attr_fid = p9_client_xattrwalk(fid, name, &attr_size);
30 if (IS_ERR(attr_fid)) {
31 retval = PTR_ERR(attr_fid);
32 p9_debug(P9_DEBUG_VFS, "p9_client_attrwalk failed %zd\n",
33 retval);
34 return retval;
35 }
36 if (attr_size > buffer_size) {
37 if (!buffer_size) /* request to get the attr_size */
38 retval = attr_size;
39 else
40 retval = -ERANGE;
41 } else {
42 iov_iter_truncate(&to, attr_size);
43 retval = p9_client_read(attr_fid, 0, &to, &err);
44 if (err)
45 retval = err;
46 }
47 p9_fid_put(attr_fid);
48 return retval;
49 }
50
51
52 /*
53 * v9fs_xattr_get()
54 *
55 * Copy an extended attribute into the buffer
56 * provided, or compute the buffer size required.
57 * Buffer is NULL to compute the size of the buffer required.
58 *
59 * Returns a negative error number on failure, or the number of bytes
60 * used / required on success.
61 */
v9fs_xattr_get(struct dentry * dentry,const char * name,void * buffer,size_t buffer_size)62 ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name,
63 void *buffer, size_t buffer_size)
64 {
65 struct p9_fid *fid;
66 int ret;
67
68 p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu\n",
69 name, buffer_size);
70 fid = v9fs_fid_lookup(dentry);
71 if (IS_ERR(fid))
72 return PTR_ERR(fid);
73 ret = v9fs_fid_xattr_get(fid, name, buffer, buffer_size);
74 p9_fid_put(fid);
75
76 return ret;
77 }
78
79 /*
80 * v9fs_xattr_set()
81 *
82 * Create, replace or remove an extended attribute for this inode. Buffer
83 * is NULL to remove an existing extended attribute, and non-NULL to
84 * either replace an existing extended attribute, or create a new extended
85 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
86 * specify that an extended attribute must exist and must not exist
87 * previous to the call, respectively.
88 *
89 * Returns 0, or a negative error number on failure.
90 */
v9fs_xattr_set(struct dentry * dentry,const char * name,const void * value,size_t value_len,int flags)91 int v9fs_xattr_set(struct dentry *dentry, const char *name,
92 const void *value, size_t value_len, int flags)
93 {
94 int ret;
95 struct p9_fid *fid;
96
97 fid = v9fs_fid_lookup(dentry);
98 if (IS_ERR(fid))
99 return PTR_ERR(fid);
100 ret = v9fs_fid_xattr_set(fid, name, value, value_len, flags);
101 p9_fid_put(fid);
102 return ret;
103 }
104
v9fs_fid_xattr_set(struct p9_fid * fid,const char * name,const void * value,size_t value_len,int flags)105 int 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, err;
111
112 iov_iter_kvec(&from, WRITE, &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 = clone_fid(fid);
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 err = p9_fid_put(fid);
132 if (!retval && err)
133 retval = err;
134 return retval;
135 }
136
v9fs_listxattr(struct dentry * dentry,char * buffer,size_t buffer_size)137 ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
138 {
139 return v9fs_xattr_get(dentry, NULL, buffer, buffer_size);
140 }
141
v9fs_xattr_handler_get(const struct xattr_handler * handler,struct dentry * dentry,struct inode * inode,const char * name,void * buffer,size_t size)142 static int v9fs_xattr_handler_get(const struct xattr_handler *handler,
143 struct dentry *dentry, struct inode *inode,
144 const char *name, void *buffer, size_t size)
145 {
146 const char *full_name = xattr_full_name(handler, name);
147
148 return v9fs_xattr_get(dentry, full_name, buffer, size);
149 }
150
v9fs_xattr_handler_set(const struct xattr_handler * handler,struct user_namespace * mnt_userns,struct dentry * dentry,struct inode * inode,const char * name,const void * value,size_t size,int flags)151 static int v9fs_xattr_handler_set(const struct xattr_handler *handler,
152 struct user_namespace *mnt_userns,
153 struct dentry *dentry, struct inode *inode,
154 const char *name, const void *value,
155 size_t size, int flags)
156 {
157 const char *full_name = xattr_full_name(handler, name);
158
159 return v9fs_xattr_set(dentry, full_name, value, size, flags);
160 }
161
162 static 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
168 static 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
175 static 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
182 const 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