Linux Kernel  3.7.1
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generic_acl.c
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1 /*
2  * (C) 2005 Andreas Gruenbacher <[email protected]>
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:
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(&init_user_ns, 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 (!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;
109 failed:
110  posix_acl_release(acl);
111  return error;
112 }
113 
120 int
121 generic_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 
151 int
152 generic_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 
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 
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 };