Root/fs/jfs/acl.c

1/*
2 * Copyright (C) International Business Machines Corp., 2002-2004
3 * Copyright (C) Andreas Gruenbacher, 2001
4 * Copyright (C) Linus Torvalds, 1991, 1992
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
14 * the GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 */
20
21#include <linux/sched.h>
22#include <linux/slab.h>
23#include <linux/fs.h>
24#include <linux/posix_acl_xattr.h>
25#include "jfs_incore.h"
26#include "jfs_txnmgr.h"
27#include "jfs_xattr.h"
28#include "jfs_acl.h"
29
30static struct posix_acl *jfs_get_acl(struct inode *inode, int type)
31{
32    struct posix_acl *acl;
33    char *ea_name;
34    int size;
35    char *value = NULL;
36
37    acl = get_cached_acl(inode, type);
38    if (acl != ACL_NOT_CACHED)
39        return acl;
40
41    switch(type) {
42        case ACL_TYPE_ACCESS:
43            ea_name = POSIX_ACL_XATTR_ACCESS;
44            break;
45        case ACL_TYPE_DEFAULT:
46            ea_name = POSIX_ACL_XATTR_DEFAULT;
47            break;
48        default:
49            return ERR_PTR(-EINVAL);
50    }
51
52    size = __jfs_getxattr(inode, ea_name, NULL, 0);
53
54    if (size > 0) {
55        value = kmalloc(size, GFP_KERNEL);
56        if (!value)
57            return ERR_PTR(-ENOMEM);
58        size = __jfs_getxattr(inode, ea_name, value, size);
59    }
60
61    if (size < 0) {
62        if (size == -ENODATA)
63            acl = NULL;
64        else
65            acl = ERR_PTR(size);
66    } else {
67        acl = posix_acl_from_xattr(value, size);
68    }
69    kfree(value);
70    if (!IS_ERR(acl))
71        set_cached_acl(inode, type, acl);
72    return acl;
73}
74
75static int jfs_set_acl(tid_t tid, struct inode *inode, int type,
76               struct posix_acl *acl)
77{
78    char *ea_name;
79    int rc;
80    int size = 0;
81    char *value = NULL;
82
83    if (S_ISLNK(inode->i_mode))
84        return -EOPNOTSUPP;
85
86    switch(type) {
87        case ACL_TYPE_ACCESS:
88            ea_name = POSIX_ACL_XATTR_ACCESS;
89            break;
90        case ACL_TYPE_DEFAULT:
91            ea_name = POSIX_ACL_XATTR_DEFAULT;
92            if (!S_ISDIR(inode->i_mode))
93                return acl ? -EACCES : 0;
94            break;
95        default:
96            return -EINVAL;
97    }
98    if (acl) {
99        size = posix_acl_xattr_size(acl->a_count);
100        value = kmalloc(size, GFP_KERNEL);
101        if (!value)
102            return -ENOMEM;
103        rc = posix_acl_to_xattr(acl, value, size);
104        if (rc < 0)
105            goto out;
106    }
107    rc = __jfs_setxattr(tid, inode, ea_name, value, size, 0);
108out:
109    kfree(value);
110
111    if (!rc)
112        set_cached_acl(inode, type, acl);
113
114    return rc;
115}
116
117int jfs_check_acl(struct inode *inode, int mask, unsigned int flags)
118{
119    struct posix_acl *acl;
120
121    if (flags & IPERM_FLAG_RCU)
122        return -ECHILD;
123
124    acl = jfs_get_acl(inode, ACL_TYPE_ACCESS);
125    if (IS_ERR(acl))
126        return PTR_ERR(acl);
127    if (acl) {
128        int error = posix_acl_permission(inode, acl, mask);
129        posix_acl_release(acl);
130        return error;
131    }
132
133    return -EAGAIN;
134}
135
136int jfs_init_acl(tid_t tid, struct inode *inode, struct inode *dir)
137{
138    struct posix_acl *acl = NULL;
139    struct posix_acl *clone;
140    mode_t mode;
141    int rc = 0;
142
143    if (S_ISLNK(inode->i_mode))
144        return 0;
145
146    acl = jfs_get_acl(dir, ACL_TYPE_DEFAULT);
147    if (IS_ERR(acl))
148        return PTR_ERR(acl);
149
150    if (acl) {
151        if (S_ISDIR(inode->i_mode)) {
152            rc = jfs_set_acl(tid, inode, ACL_TYPE_DEFAULT, acl);
153            if (rc)
154                goto cleanup;
155        }
156        clone = posix_acl_clone(acl, GFP_KERNEL);
157        if (!clone) {
158            rc = -ENOMEM;
159            goto cleanup;
160        }
161        mode = inode->i_mode;
162        rc = posix_acl_create_masq(clone, &mode);
163        if (rc >= 0) {
164            inode->i_mode = mode;
165            if (rc > 0)
166                rc = jfs_set_acl(tid, inode, ACL_TYPE_ACCESS,
167                         clone);
168        }
169        posix_acl_release(clone);
170cleanup:
171        posix_acl_release(acl);
172    } else
173        inode->i_mode &= ~current_umask();
174
175    JFS_IP(inode)->mode2 = (JFS_IP(inode)->mode2 & 0xffff0000) |
176                   inode->i_mode;
177
178    return rc;
179}
180
181int jfs_acl_chmod(struct inode *inode)
182{
183    struct posix_acl *acl, *clone;
184    int rc;
185
186    if (S_ISLNK(inode->i_mode))
187        return -EOPNOTSUPP;
188
189    acl = jfs_get_acl(inode, ACL_TYPE_ACCESS);
190    if (IS_ERR(acl) || !acl)
191        return PTR_ERR(acl);
192
193    clone = posix_acl_clone(acl, GFP_KERNEL);
194    posix_acl_release(acl);
195    if (!clone)
196        return -ENOMEM;
197
198    rc = posix_acl_chmod_masq(clone, inode->i_mode);
199    if (!rc) {
200        tid_t tid = txBegin(inode->i_sb, 0);
201        mutex_lock(&JFS_IP(inode)->commit_mutex);
202        rc = jfs_set_acl(tid, inode, ACL_TYPE_ACCESS, clone);
203        if (!rc)
204            rc = txCommit(tid, 1, &inode, 0);
205        txEnd(tid);
206        mutex_unlock(&JFS_IP(inode)->commit_mutex);
207    }
208
209    posix_acl_release(clone);
210    return rc;
211}
212

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