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(&init_user_ns, 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 (!inode_owner_or_capable(inode))
78 return -EPERM;
79 if (value) {
80 acl = posix_acl_from_xattr(&init_user_ns, value, size);
81 if (IS_ERR(acl))
82 return PTR_ERR(acl);
83 }
84 if (acl) {
85 error = posix_acl_valid(acl);
86 if (error)
87 goto failed;
88 switch (type) {
89 case ACL_TYPE_ACCESS:
90 error = posix_acl_equiv_mode(acl, &inode->i_mode);
91 if (error < 0)
92 goto failed;
93 inode->i_ctime = CURRENT_TIME;
94 if (error == 0) {
95 posix_acl_release(acl);
96 acl = NULL;
97 }
98 break;
99 case ACL_TYPE_DEFAULT:
100 if (!S_ISDIR(inode->i_mode)) {
101 error = -EINVAL;
102 goto failed;
103 }
104 break;
105 }
106 }
107 set_cached_acl(inode, type, acl);
108 error = 0;
109failed:
110 posix_acl_release(acl);
111 return error;
112}
113
114/**
115 * generic_acl_init - Take care of acl inheritance at @inode create time
116 *
117 * Files created inside a directory with a default ACL inherit the
118 * directory's default ACL.
119 */
120int
121generic_acl_init(struct inode *inode, struct inode *dir)
122{
123 struct posix_acl *acl = NULL;
124 int error;
125
126 if (!S_ISLNK(inode->i_mode))
127 acl = get_cached_acl(dir, ACL_TYPE_DEFAULT);
128 if (acl) {
129 if (S_ISDIR(inode->i_mode))
130 set_cached_acl(inode, ACL_TYPE_DEFAULT, acl);
131 error = posix_acl_create(&acl, GFP_KERNEL, &inode->i_mode);
132 if (error < 0)
133 return error;
134 if (error > 0)
135 set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
136 } else {
137 inode->i_mode &= ~current_umask();
138 }
139 error = 0;
140
141 posix_acl_release(acl);
142 return error;
143}
144
145/**
146 * generic_acl_chmod - change the access acl of @inode upon chmod()
147 *
148 * A chmod also changes the permissions of the owner, group/mask, and
149 * other ACL entries.
150 */
151int
152generic_acl_chmod(struct inode *inode)
153{
154 struct posix_acl *acl;
155 int error = 0;
156
157 if (S_ISLNK(inode->i_mode))
158 return -EOPNOTSUPP;
159 acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
160 if (acl) {
161 error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
162 if (error)
163 return error;
164 set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
165 posix_acl_release(acl);
166 }
167 return error;
168}
169
170const struct xattr_handler generic_acl_access_handler = {
171 .prefix = POSIX_ACL_XATTR_ACCESS,
172 .flags = ACL_TYPE_ACCESS,
173 .list = generic_acl_list,
174 .get = generic_acl_get,
175 .set = generic_acl_set,
176};
177
178const struct xattr_handler generic_acl_default_handler = {
179 .prefix = POSIX_ACL_XATTR_DEFAULT,
180 .flags = ACL_TYPE_DEFAULT,
181 .list = generic_acl_list,
182 .get = generic_acl_get,
183 .set = generic_acl_set,
184};