1/*
2 * linux/fs/ceph/acl.c
3 *
4 * Copyright (C) 2013 Guangliang Zhao, <lucienchao@gmail.com>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public
8 * License v2 as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public
16 * License along with this program; if not, write to the
17 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 * Boston, MA 021110-1307, USA.
19 */
20
21#include <linux/ceph/ceph_debug.h>
22#include <linux/fs.h>
23#include <linux/string.h>
24#include <linux/xattr.h>
25#include <linux/posix_acl_xattr.h>
26#include <linux/posix_acl.h>
27#include <linux/sched.h>
28#include <linux/slab.h>
29
30#include "super.h"
31
32static inline void ceph_set_cached_acl(struct inode *inode,
33					int type, struct posix_acl *acl)
34{
35	struct ceph_inode_info *ci = ceph_inode(inode);
36
37	spin_lock(&ci->i_ceph_lock);
38	if (__ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED, 0))
39		set_cached_acl(inode, type, acl);
40	spin_unlock(&ci->i_ceph_lock);
41}
42
43struct posix_acl *ceph_get_acl(struct inode *inode, int type)
44{
45	int size;
46	const char *name;
47	char *value = NULL;
48	struct posix_acl *acl;
49
50	switch (type) {
51	case ACL_TYPE_ACCESS:
52		name = POSIX_ACL_XATTR_ACCESS;
53		break;
54	case ACL_TYPE_DEFAULT:
55		name = POSIX_ACL_XATTR_DEFAULT;
56		break;
57	default:
58		BUG();
59	}
60
61	size = __ceph_getxattr(inode, name, "", 0);
62	if (size > 0) {
63		value = kzalloc(size, GFP_NOFS);
64		if (!value)
65			return ERR_PTR(-ENOMEM);
66		size = __ceph_getxattr(inode, name, value, size);
67	}
68
69	if (size > 0)
70		acl = posix_acl_from_xattr(&init_user_ns, value, size);
71	else if (size == -ERANGE || size == -ENODATA || size == 0)
72		acl = NULL;
73	else
74		acl = ERR_PTR(-EIO);
75
76	kfree(value);
77
78	if (!IS_ERR(acl))
79		ceph_set_cached_acl(inode, type, acl);
80
81	return acl;
82}
83
84int ceph_set_acl(struct inode *inode, struct posix_acl *acl, int type)
85{
86	int ret = 0, size = 0;
87	const char *name = NULL;
88	char *value = NULL;
89	struct iattr newattrs;
90	umode_t new_mode = inode->i_mode, old_mode = inode->i_mode;
91	struct dentry *dentry;
92
93	switch (type) {
94	case ACL_TYPE_ACCESS:
95		name = POSIX_ACL_XATTR_ACCESS;
96		if (acl) {
97			ret = posix_acl_equiv_mode(acl, &new_mode);
98			if (ret < 0)
99				goto out;
100			if (ret == 0)
101				acl = NULL;
102		}
103		break;
104	case ACL_TYPE_DEFAULT:
105		if (!S_ISDIR(inode->i_mode)) {
106			ret = acl ? -EINVAL : 0;
107			goto out;
108		}
109		name = POSIX_ACL_XATTR_DEFAULT;
110		break;
111	default:
112		ret = -EINVAL;
113		goto out;
114	}
115
116	if (acl) {
117		size = posix_acl_xattr_size(acl->a_count);
118		value = kmalloc(size, GFP_NOFS);
119		if (!value) {
120			ret = -ENOMEM;
121			goto out;
122		}
123
124		ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
125		if (ret < 0)
126			goto out_free;
127	}
128
129	dentry = d_find_alias(inode);
130	if (new_mode != old_mode) {
131		newattrs.ia_mode = new_mode;
132		newattrs.ia_valid = ATTR_MODE;
133		ret = ceph_setattr(dentry, &newattrs);
134		if (ret)
135			goto out_dput;
136	}
137
138	ret = __ceph_setxattr(dentry, name, value, size, 0);
139	if (ret) {
140		if (new_mode != old_mode) {
141			newattrs.ia_mode = old_mode;
142			newattrs.ia_valid = ATTR_MODE;
143			ceph_setattr(dentry, &newattrs);
144		}
145		goto out_dput;
146	}
147
148	ceph_set_cached_acl(inode, type, acl);
149
150out_dput:
151	dput(dentry);
152out_free:
153	kfree(value);
154out:
155	return ret;
156}
157
158int ceph_pre_init_acls(struct inode *dir, umode_t *mode,
159		       struct ceph_acls_info *info)
160{
161	struct posix_acl *acl, *default_acl;
162	size_t val_size1 = 0, val_size2 = 0;
163	struct ceph_pagelist *pagelist = NULL;
164	void *tmp_buf = NULL;
165	int err;
166
167	err = posix_acl_create(dir, mode, &default_acl, &acl);
168	if (err)
169		return err;
170
171	if (acl) {
172		int ret = posix_acl_equiv_mode(acl, mode);
173		if (ret < 0)
174			goto out_err;
175		if (ret == 0) {
176			posix_acl_release(acl);
177			acl = NULL;
178		}
179	}
180
181	if (!default_acl && !acl)
182		return 0;
183
184	if (acl)
185		val_size1 = posix_acl_xattr_size(acl->a_count);
186	if (default_acl)
187		val_size2 = posix_acl_xattr_size(default_acl->a_count);
188
189	err = -ENOMEM;
190	tmp_buf = kmalloc(max(val_size1, val_size2), GFP_KERNEL);
191	if (!tmp_buf)
192		goto out_err;
193	pagelist = kmalloc(sizeof(struct ceph_pagelist), GFP_KERNEL);
194	if (!pagelist)
195		goto out_err;
196	ceph_pagelist_init(pagelist);
197
198	err = ceph_pagelist_reserve(pagelist, PAGE_SIZE);
199	if (err)
200		goto out_err;
201
202	ceph_pagelist_encode_32(pagelist, acl && default_acl ? 2 : 1);
203
204	if (acl) {
205		size_t len = strlen(POSIX_ACL_XATTR_ACCESS);
206		err = ceph_pagelist_reserve(pagelist, len + val_size1 + 8);
207		if (err)
208			goto out_err;
209		ceph_pagelist_encode_string(pagelist, POSIX_ACL_XATTR_ACCESS,
210					    len);
211		err = posix_acl_to_xattr(&init_user_ns, acl,
212					 tmp_buf, val_size1);
213		if (err < 0)
214			goto out_err;
215		ceph_pagelist_encode_32(pagelist, val_size1);
216		ceph_pagelist_append(pagelist, tmp_buf, val_size1);
217	}
218	if (default_acl) {
219		size_t len = strlen(POSIX_ACL_XATTR_DEFAULT);
220		err = ceph_pagelist_reserve(pagelist, len + val_size2 + 8);
221		if (err)
222			goto out_err;
223		err = ceph_pagelist_encode_string(pagelist,
224						  POSIX_ACL_XATTR_DEFAULT, len);
225		err = posix_acl_to_xattr(&init_user_ns, default_acl,
226					 tmp_buf, val_size2);
227		if (err < 0)
228			goto out_err;
229		ceph_pagelist_encode_32(pagelist, val_size2);
230		ceph_pagelist_append(pagelist, tmp_buf, val_size2);
231	}
232
233	kfree(tmp_buf);
234
235	info->acl = acl;
236	info->default_acl = default_acl;
237	info->pagelist = pagelist;
238	return 0;
239
240out_err:
241	posix_acl_release(acl);
242	posix_acl_release(default_acl);
243	kfree(tmp_buf);
244	if (pagelist)
245		ceph_pagelist_release(pagelist);
246	return err;
247}
248
249void ceph_init_inode_acls(struct inode* inode, struct ceph_acls_info *info)
250{
251	if (!inode)
252		return;
253	ceph_set_cached_acl(inode, ACL_TYPE_ACCESS, info->acl);
254	ceph_set_cached_acl(inode, ACL_TYPE_DEFAULT, info->default_acl);
255}
256
257void ceph_release_acls_info(struct ceph_acls_info *info)
258{
259	posix_acl_release(info->acl);
260	posix_acl_release(info->default_acl);
261	if (info->pagelist)
262		ceph_pagelist_release(info->pagelist);
263}
264