Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wirel...
[pandora-kernel.git] / fs / generic_acl.c
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
17 static size_t
18 generic_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
46 static int
47 generic_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
65 static int
66 generic_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;
112 failed:
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  */
123 int
124 generic_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
158 cleanup:
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  */
169 int
170 generic_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
191 int
192 generic_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
204 const struct 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
212 const struct 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 };