1/*
2 * FUSE: Filesystem in Userspace
3 * Copyright (C) 2001-2016 Miklos Szeredi <miklos@szeredi.hu>
4 *
5 * This program can be distributed under the terms of the GNU GPL.
6 * See the file COPYING.
7 */
8
9#include "fuse_i.h"
10
11#include <linux/xattr.h>
12#include <linux/posix_acl_xattr.h>
13
14int fuse_setxattr(struct inode *inode, const char *name, const void *value,
15 size_t size, int flags, unsigned int extra_flags)
16{
17 struct fuse_mount *fm = get_fuse_mount(inode);
18 FUSE_ARGS(args);
19 struct fuse_setxattr_in inarg;
20 int err;
21
22 if (fm->fc->no_setxattr)
23 return -EOPNOTSUPP;
24
25 memset(&inarg, 0, sizeof(inarg));
26 inarg.size = size;
27 inarg.flags = flags;
28 inarg.setxattr_flags = extra_flags;
29
30 args.opcode = FUSE_SETXATTR;
31 args.nodeid = get_node_id(inode);
32 args.in_numargs = 3;
33 args.in_args[0].size = fm->fc->setxattr_ext ?
34 sizeof(inarg) : FUSE_COMPAT_SETXATTR_IN_SIZE;
35 args.in_args[0].value = &inarg;
36 args.in_args[1].size = strlen(name) + 1;
37 args.in_args[1].value = name;
38 args.in_args[2].size = size;
39 args.in_args[2].value = value;
40 err = fuse_simple_request(fm, args: &args);
41 if (err == -ENOSYS) {
42 fm->fc->no_setxattr = 1;
43 err = -EOPNOTSUPP;
44 }
45 if (!err)
46 fuse_update_ctime(inode);
47
48 return err;
49}
50
51ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
52 size_t size)
53{
54 struct fuse_mount *fm = get_fuse_mount(inode);
55 FUSE_ARGS(args);
56 struct fuse_getxattr_in inarg;
57 struct fuse_getxattr_out outarg;
58 ssize_t ret;
59
60 if (fm->fc->no_getxattr)
61 return -EOPNOTSUPP;
62
63 memset(&inarg, 0, sizeof(inarg));
64 inarg.size = size;
65 args.opcode = FUSE_GETXATTR;
66 args.nodeid = get_node_id(inode);
67 args.in_numargs = 2;
68 args.in_args[0].size = sizeof(inarg);
69 args.in_args[0].value = &inarg;
70 args.in_args[1].size = strlen(name) + 1;
71 args.in_args[1].value = name;
72 /* This is really two different operations rolled into one */
73 args.out_numargs = 1;
74 if (size) {
75 args.out_argvar = true;
76 args.out_args[0].size = size;
77 args.out_args[0].value = value;
78 } else {
79 args.out_args[0].size = sizeof(outarg);
80 args.out_args[0].value = &outarg;
81 }
82 ret = fuse_simple_request(fm, args: &args);
83 if (!ret && !size)
84 ret = min_t(size_t, outarg.size, XATTR_SIZE_MAX);
85 if (ret == -ENOSYS) {
86 fm->fc->no_getxattr = 1;
87 ret = -EOPNOTSUPP;
88 }
89 return ret;
90}
91
92static int fuse_verify_xattr_list(char *list, size_t size)
93{
94 size_t origsize = size;
95
96 while (size) {
97 size_t thislen = strnlen(p: list, maxlen: size);
98
99 if (!thislen || thislen == size)
100 return -EIO;
101
102 size -= thislen + 1;
103 list += thislen + 1;
104 }
105
106 return origsize;
107}
108
109ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
110{
111 struct inode *inode = d_inode(dentry: entry);
112 struct fuse_mount *fm = get_fuse_mount(inode);
113 FUSE_ARGS(args);
114 struct fuse_getxattr_in inarg;
115 struct fuse_getxattr_out outarg;
116 ssize_t ret;
117
118 if (fuse_is_bad(inode))
119 return -EIO;
120
121 if (!fuse_allow_current_process(fc: fm->fc))
122 return -EACCES;
123
124 if (fm->fc->no_listxattr)
125 return -EOPNOTSUPP;
126
127 memset(&inarg, 0, sizeof(inarg));
128 inarg.size = size;
129 args.opcode = FUSE_LISTXATTR;
130 args.nodeid = get_node_id(inode);
131 args.in_numargs = 1;
132 args.in_args[0].size = sizeof(inarg);
133 args.in_args[0].value = &inarg;
134 /* This is really two different operations rolled into one */
135 args.out_numargs = 1;
136 if (size) {
137 args.out_argvar = true;
138 args.out_args[0].size = size;
139 args.out_args[0].value = list;
140 } else {
141 args.out_args[0].size = sizeof(outarg);
142 args.out_args[0].value = &outarg;
143 }
144 ret = fuse_simple_request(fm, args: &args);
145 if (!ret && !size)
146 ret = min_t(size_t, outarg.size, XATTR_LIST_MAX);
147 if (ret > 0 && size)
148 ret = fuse_verify_xattr_list(list, size: ret);
149 if (ret == -ENOSYS) {
150 fm->fc->no_listxattr = 1;
151 ret = -EOPNOTSUPP;
152 }
153 return ret;
154}
155
156int fuse_removexattr(struct inode *inode, const char *name)
157{
158 struct fuse_mount *fm = get_fuse_mount(inode);
159 FUSE_ARGS(args);
160 int err;
161
162 if (fm->fc->no_removexattr)
163 return -EOPNOTSUPP;
164
165 args.opcode = FUSE_REMOVEXATTR;
166 args.nodeid = get_node_id(inode);
167 args.in_numargs = 2;
168 fuse_set_zero_arg0(args: &args);
169 args.in_args[1].size = strlen(name) + 1;
170 args.in_args[1].value = name;
171 err = fuse_simple_request(fm, args: &args);
172 if (err == -ENOSYS) {
173 fm->fc->no_removexattr = 1;
174 err = -EOPNOTSUPP;
175 }
176 if (!err)
177 fuse_update_ctime(inode);
178
179 return err;
180}
181
182static int fuse_xattr_get(const struct xattr_handler *handler,
183 struct dentry *dentry, struct inode *inode,
184 const char *name, void *value, size_t size)
185{
186 if (fuse_is_bad(inode))
187 return -EIO;
188
189 return fuse_getxattr(inode, name, value, size);
190}
191
192static int fuse_xattr_set(const struct xattr_handler *handler,
193 struct mnt_idmap *idmap,
194 struct dentry *dentry, struct inode *inode,
195 const char *name, const void *value, size_t size,
196 int flags)
197{
198 if (fuse_is_bad(inode))
199 return -EIO;
200
201 if (!value)
202 return fuse_removexattr(inode, name);
203
204 return fuse_setxattr(inode, name, value, size, flags, extra_flags: 0);
205}
206
207static const struct xattr_handler fuse_xattr_handler = {
208 .prefix = "",
209 .get = fuse_xattr_get,
210 .set = fuse_xattr_set,
211};
212
213const struct xattr_handler * const fuse_xattr_handlers[] = {
214 &fuse_xattr_handler,
215 NULL
216};
217

source code of linux/fs/fuse/xattr.c