Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1/*
2 * (C) 2005 Andreas Gruenbacher <agruen@suse.de>
3 *
4 * This file is released under the GPL.
5 *
6 * Generic ACL support for in-memory filesystems.
7 */
8
9#include <linux/sched.h>
10#include <linux/gfp.h>
11#include <linux/fs.h>
12#include <linux/generic_acl.h>
13#include <linux/posix_acl.h>
14#include <linux/posix_acl_xattr.h>
15
16
17static size_t
18generic_acl_list(struct dentry *dentry, char *list, size_t list_size,
19 const char *name, size_t name_len, int type)
20{
21 struct posix_acl *acl;
22 const char *xname;
23 size_t size;
24
25 acl = get_cached_acl(dentry->d_inode, type);
26 if (!acl)
27 return 0;
28 posix_acl_release(acl);
29
30 switch (type) {
31 case ACL_TYPE_ACCESS:
32 xname = POSIX_ACL_XATTR_ACCESS;
33 break;
34 case ACL_TYPE_DEFAULT:
35 xname = POSIX_ACL_XATTR_DEFAULT;
36 break;
37 default:
38 return 0;
39 }
40 size = strlen(xname) + 1;
41 if (list && size <= list_size)
42 memcpy(list, xname, size);
43 return size;
44}
45
46static int
47generic_acl_get(struct dentry *dentry, const char *name, void *buffer,
48 size_t size, int type)
49{
50 struct posix_acl *acl;
51 int error;
52
53 if (strcmp(name, "") != 0)
54 return -EINVAL;
55
56 acl = get_cached_acl(dentry->d_inode, type);
57 if (!acl)
58 return -ENODATA;
59 error = posix_acl_to_xattr(acl, buffer, size);
60 posix_acl_release(acl);
61
62 return error;
63}
64
65static int
66generic_acl_set(struct dentry *dentry, const char *name, const void *value,
67 size_t size, int flags, int type)
68{
69 struct inode *inode = dentry->d_inode;
70 struct posix_acl *acl = NULL;
71 int error;
72
73 if (strcmp(name, "") != 0)
74 return -EINVAL;
75 if (S_ISLNK(inode->i_mode))
76 return -EOPNOTSUPP;
77 if (!is_owner_or_cap(inode))
78 return -EPERM;
79 if (value) {
80 acl = posix_acl_from_xattr(value, size);
81 if (IS_ERR(acl))
82 return PTR_ERR(acl);
83 }
84 if (acl) {
85 mode_t mode;
86
87 error = posix_acl_valid(acl);
88 if (error)
89 goto failed;
90 switch (type) {
91 case ACL_TYPE_ACCESS:
92 mode = inode->i_mode;
93 error = posix_acl_equiv_mode(acl, &mode);
94 if (error < 0)
95 goto failed;
96 inode->i_mode = mode;
97 if (error == 0) {
98 posix_acl_release(acl);
99 acl = NULL;
100 }
101 break;
102 case ACL_TYPE_DEFAULT:
103 if (!S_ISDIR(inode->i_mode)) {
104 error = -EINVAL;
105 goto failed;
106 }
107 break;
108 }
109 }
110 set_cached_acl(inode, type, acl);
111 error = 0;
112failed:
113 posix_acl_release(acl);
114 return error;
115}
116
117/**
118 * generic_acl_init - Take care of acl inheritance at @inode create time
119 *
120 * Files created inside a directory with a default ACL inherit the
121 * directory's default ACL.
122 */
123int
124generic_acl_init(struct inode *inode, struct inode *dir)
125{
126 struct posix_acl *acl = NULL;
127 mode_t mode = inode->i_mode;
128 int error;
129
130 inode->i_mode = mode & ~current_umask();
131 if (!S_ISLNK(inode->i_mode))
132 acl = get_cached_acl(dir, ACL_TYPE_DEFAULT);
133 if (acl) {
134 struct posix_acl *clone;
135
136 if (S_ISDIR(inode->i_mode)) {
137 clone = posix_acl_clone(acl, GFP_KERNEL);
138 error = -ENOMEM;
139 if (!clone)
140 goto cleanup;
141 set_cached_acl(inode, ACL_TYPE_DEFAULT, clone);
142 posix_acl_release(clone);
143 }
144 clone = posix_acl_clone(acl, GFP_KERNEL);
145 error = -ENOMEM;
146 if (!clone)
147 goto cleanup;
148 error = posix_acl_create_masq(clone, &mode);
149 if (error >= 0) {
150 inode->i_mode = mode;
151 if (error > 0)
152 set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
153 }
154 posix_acl_release(clone);
155 }
156 error = 0;
157
158cleanup:
159 posix_acl_release(acl);
160 return error;
161}
162
163/**
164 * generic_acl_chmod - change the access acl of @inode upon chmod()
165 *
166 * A chmod also changes the permissions of the owner, group/mask, and
167 * other ACL entries.
168 */
169int
170generic_acl_chmod(struct inode *inode)
171{
172 struct posix_acl *acl, *clone;
173 int error = 0;
174
175 if (S_ISLNK(inode->i_mode))
176 return -EOPNOTSUPP;
177 acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
178 if (acl) {
179 clone = posix_acl_clone(acl, GFP_KERNEL);
180 posix_acl_release(acl);
181 if (!clone)
182 return -ENOMEM;
183 error = posix_acl_chmod_masq(clone, inode->i_mode);
184 if (!error)
185 set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
186 posix_acl_release(clone);
187 }
188 return error;
189}
190
191int
192generic_check_acl(struct inode *inode, int mask)
193{
194 struct posix_acl *acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
195
196 if (acl) {
197 int error = posix_acl_permission(inode, acl, mask);
198 posix_acl_release(acl);
199 return error;
200 }
201 return -EAGAIN;
202}
203
204struct xattr_handler generic_acl_access_handler = {
205 .prefix = POSIX_ACL_XATTR_ACCESS,
206 .flags = ACL_TYPE_ACCESS,
207 .list = generic_acl_list,
208 .get = generic_acl_get,
209 .set = generic_acl_set,
210};
211
212struct xattr_handler generic_acl_default_handler = {
213 .prefix = POSIX_ACL_XATTR_DEFAULT,
214 .flags = ACL_TYPE_DEFAULT,
215 .list = generic_acl_list,
216 .get = generic_acl_get,
217 .set = generic_acl_set,
218};