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(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(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(size_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};