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);
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);
83	if (!ret && !size)
84		ret = min_t(ssize_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(list, 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(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(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);
145	if (!ret && !size)
146		ret = min_t(ssize_t, outarg.size, XATTR_LIST_MAX);
147	if (ret > 0 && size)
148		ret = fuse_verify_xattr_list(list, 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 = 1;
168	args.in_args[0].size = strlen(name) + 1;
169	args.in_args[0].value = name;
170	err = fuse_simple_request(fm, &args);
171	if (err == -ENOSYS) {
172		fm->fc->no_removexattr = 1;
173		err = -EOPNOTSUPP;
174	}
175	if (!err)
176		fuse_update_ctime(inode);
177
178	return err;
179}
180
181static int fuse_xattr_get(const struct xattr_handler *handler,
182			 struct dentry *dentry, struct inode *inode,
183			 const char *name, void *value, size_t size)
184{
185	if (fuse_is_bad(inode))
186		return -EIO;
187
188	return fuse_getxattr(inode, name, value, size);
189}
190
191static int fuse_xattr_set(const struct xattr_handler *handler,
192			  struct mnt_idmap *idmap,
193			  struct dentry *dentry, struct inode *inode,
194			  const char *name, const void *value, size_t size,
195			  int flags)
196{
197	if (fuse_is_bad(inode))
198		return -EIO;
199
200	if (!value)
201		return fuse_removexattr(inode, name);
202
203	return fuse_setxattr(inode, name, value, size, flags, 0);
204}
205
206static const struct xattr_handler fuse_xattr_handler = {
207	.prefix = "",
208	.get    = fuse_xattr_get,
209	.set    = fuse_xattr_set,
210};
211
212const struct xattr_handler * const fuse_xattr_handlers[] = {
213	&fuse_xattr_handler,
214	NULL
215};
216