1 /*
2 * mm/shmem_acl.c
3 *
4 * (C) 2005 Andreas Gruenbacher <agruen@suse.de>
5 *
6 * This file is released under the GPL.
7 */
8
9 #include <linux/fs.h>
10 #include <linux/shmem_fs.h>
11 #include <linux/xattr.h>
12 #include <linux/generic_acl.h>
13
14 /**
15 * shmem_get_acl - generic_acl_operations->getacl() operation
16 */
17 static struct posix_acl *
shmem_get_acl(struct inode * inode,int type)18 shmem_get_acl(struct inode *inode, int type)
19 {
20 struct posix_acl *acl = NULL;
21
22 spin_lock(&inode->i_lock);
23 switch(type) {
24 case ACL_TYPE_ACCESS:
25 acl = posix_acl_dup(SHMEM_I(inode)->i_acl);
26 break;
27
28 case ACL_TYPE_DEFAULT:
29 acl = posix_acl_dup(SHMEM_I(inode)->i_default_acl);
30 break;
31 }
32 spin_unlock(&inode->i_lock);
33
34 return acl;
35 }
36
37 /**
38 * shmem_set_acl - generic_acl_operations->setacl() operation
39 */
40 static void
shmem_set_acl(struct inode * inode,int type,struct posix_acl * acl)41 shmem_set_acl(struct inode *inode, int type, struct posix_acl *acl)
42 {
43 struct posix_acl *free = NULL;
44
45 spin_lock(&inode->i_lock);
46 switch(type) {
47 case ACL_TYPE_ACCESS:
48 free = SHMEM_I(inode)->i_acl;
49 SHMEM_I(inode)->i_acl = posix_acl_dup(acl);
50 break;
51
52 case ACL_TYPE_DEFAULT:
53 free = SHMEM_I(inode)->i_default_acl;
54 SHMEM_I(inode)->i_default_acl = posix_acl_dup(acl);
55 break;
56 }
57 spin_unlock(&inode->i_lock);
58 posix_acl_release(free);
59 }
60
61 struct generic_acl_operations shmem_acl_ops = {
62 .getacl = shmem_get_acl,
63 .setacl = shmem_set_acl,
64 };
65
66 /**
67 * shmem_list_acl_access, shmem_get_acl_access, shmem_set_acl_access,
68 * shmem_xattr_acl_access_handler - plumbing code to implement the
69 * system.posix_acl_access xattr using the generic acl functions.
70 */
71
72 static size_t
shmem_list_acl_access(struct inode * inode,char * list,size_t list_size,const char * name,size_t name_len)73 shmem_list_acl_access(struct inode *inode, char *list, size_t list_size,
74 const char *name, size_t name_len)
75 {
76 return generic_acl_list(inode, &shmem_acl_ops, ACL_TYPE_ACCESS,
77 list, list_size);
78 }
79
80 static int
shmem_get_acl_access(struct inode * inode,const char * name,void * buffer,size_t size)81 shmem_get_acl_access(struct inode *inode, const char *name, void *buffer,
82 size_t size)
83 {
84 if (strcmp(name, "") != 0)
85 return -EINVAL;
86 return generic_acl_get(inode, &shmem_acl_ops, ACL_TYPE_ACCESS, buffer,
87 size);
88 }
89
90 static int
shmem_set_acl_access(struct inode * inode,const char * name,const void * value,size_t size,int flags)91 shmem_set_acl_access(struct inode *inode, const char *name, const void *value,
92 size_t size, int flags)
93 {
94 if (strcmp(name, "") != 0)
95 return -EINVAL;
96 return generic_acl_set(inode, &shmem_acl_ops, ACL_TYPE_ACCESS, value,
97 size);
98 }
99
100 struct xattr_handler shmem_xattr_acl_access_handler = {
101 .prefix = POSIX_ACL_XATTR_ACCESS,
102 .list = shmem_list_acl_access,
103 .get = shmem_get_acl_access,
104 .set = shmem_set_acl_access,
105 };
106
107 /**
108 * shmem_list_acl_default, shmem_get_acl_default, shmem_set_acl_default,
109 * shmem_xattr_acl_default_handler - plumbing code to implement the
110 * system.posix_acl_default xattr using the generic acl functions.
111 */
112
113 static size_t
shmem_list_acl_default(struct inode * inode,char * list,size_t list_size,const char * name,size_t name_len)114 shmem_list_acl_default(struct inode *inode, char *list, size_t list_size,
115 const char *name, size_t name_len)
116 {
117 return generic_acl_list(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT,
118 list, list_size);
119 }
120
121 static int
shmem_get_acl_default(struct inode * inode,const char * name,void * buffer,size_t size)122 shmem_get_acl_default(struct inode *inode, const char *name, void *buffer,
123 size_t size)
124 {
125 if (strcmp(name, "") != 0)
126 return -EINVAL;
127 return generic_acl_get(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT, buffer,
128 size);
129 }
130
131 static int
shmem_set_acl_default(struct inode * inode,const char * name,const void * value,size_t size,int flags)132 shmem_set_acl_default(struct inode *inode, const char *name, const void *value,
133 size_t size, int flags)
134 {
135 if (strcmp(name, "") != 0)
136 return -EINVAL;
137 return generic_acl_set(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT, value,
138 size);
139 }
140
141 struct xattr_handler shmem_xattr_acl_default_handler = {
142 .prefix = POSIX_ACL_XATTR_DEFAULT,
143 .list = shmem_list_acl_default,
144 .get = shmem_get_acl_default,
145 .set = shmem_set_acl_default,
146 };
147
148 /**
149 * shmem_acl_init - Inizialize the acl(s) of a new inode
150 */
151 int
shmem_acl_init(struct inode * inode,struct inode * dir)152 shmem_acl_init(struct inode *inode, struct inode *dir)
153 {
154 return generic_acl_init(inode, dir, &shmem_acl_ops);
155 }
156
157 /**
158 * shmem_acl_destroy_inode - destroy acls hanging off the in-memory inode
159 *
160 * This is done before destroying the actual inode.
161 */
162
163 void
shmem_acl_destroy_inode(struct inode * inode)164 shmem_acl_destroy_inode(struct inode *inode)
165 {
166 if (SHMEM_I(inode)->i_acl)
167 posix_acl_release(SHMEM_I(inode)->i_acl);
168 SHMEM_I(inode)->i_acl = NULL;
169 if (SHMEM_I(inode)->i_default_acl)
170 posix_acl_release(SHMEM_I(inode)->i_default_acl);
171 SHMEM_I(inode)->i_default_acl = NULL;
172 }
173
174 /**
175 * shmem_check_acl - check_acl() callback for generic_permission()
176 */
177 static int
shmem_check_acl(struct inode * inode,int mask)178 shmem_check_acl(struct inode *inode, int mask)
179 {
180 struct posix_acl *acl = shmem_get_acl(inode, ACL_TYPE_ACCESS);
181
182 if (acl) {
183 int error = posix_acl_permission(inode, acl, mask);
184 posix_acl_release(acl);
185 return error;
186 }
187 return -EAGAIN;
188 }
189
190 /**
191 * shmem_permission - permission() inode operation
192 */
193 int
shmem_permission(struct inode * inode,int mask)194 shmem_permission(struct inode *inode, int mask)
195 {
196 return generic_permission(inode, mask, shmem_check_acl);
197 }
198