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(i: &to, ITER_DEST, kvec: &kvec, nr_segs: 1, count: buffer_size); |
29 | |
30 | attr_fid = p9_client_xattrwalk(file_fid: fid, attr_name: name, attr_size: &attr_size); |
31 | if (IS_ERR(ptr: attr_fid)) { |
32 | retval = PTR_ERR(ptr: 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(i: &to, count: attr_size); |
46 | retval = p9_client_read(fid: attr_fid, offset: 0, to: &to, err: &err); |
47 | if (err) |
48 | retval = err; |
49 | } |
50 | p9_fid_put(fid: 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(ptr: fid)) |
75 | return PTR_ERR(ptr: 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(ptr: fid)) |
102 | return PTR_ERR(ptr: 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(i: &from, ITER_SOURCE, kvec: &kvec, nr_segs: 1, count: 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(ptr: fid)) |
123 | return PTR_ERR(ptr: fid); |
124 | |
125 | /* |
126 | * On success fid points to xattr |
127 | */ |
128 | retval = p9_client_xattrcreate(fid, name, attr_size: 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, offset: 0, from: &from, err: &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, name: "" , 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, name: full_name, buffer, buffer_size: 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, name: full_name, value, value_len: 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 | |