Root/fs/generic_acl.c

1/*
2 * fs/generic_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/sched.h>
10#include <linux/fs.h>
11#include <linux/generic_acl.h>
12
13/**
14 * generic_acl_list - Generic xattr_handler->list() operation
15 * @ops: Filesystem specific getacl and setacl callbacks
16 */
17size_t
18generic_acl_list(struct inode *inode, struct generic_acl_operations *ops,
19         int type, char *list, size_t list_size)
20{
21    struct posix_acl *acl;
22    const char *name;
23    size_t size;
24
25    acl = ops->getacl(inode, type);
26    if (!acl)
27        return 0;
28    posix_acl_release(acl);
29
30    switch(type) {
31        case ACL_TYPE_ACCESS:
32            name = POSIX_ACL_XATTR_ACCESS;
33            break;
34
35        case ACL_TYPE_DEFAULT:
36            name = POSIX_ACL_XATTR_DEFAULT;
37            break;
38
39        default:
40            return 0;
41    }
42    size = strlen(name) + 1;
43    if (list && size <= list_size)
44        memcpy(list, name, size);
45    return size;
46}
47
48/**
49 * generic_acl_get - Generic xattr_handler->get() operation
50 * @ops: Filesystem specific getacl and setacl callbacks
51 */
52int
53generic_acl_get(struct inode *inode, struct generic_acl_operations *ops,
54        int type, void *buffer, size_t size)
55{
56    struct posix_acl *acl;
57    int error;
58
59    acl = ops->getacl(inode, type);
60    if (!acl)
61        return -ENODATA;
62    error = posix_acl_to_xattr(acl, buffer, size);
63    posix_acl_release(acl);
64
65    return error;
66}
67
68/**
69 * generic_acl_set - Generic xattr_handler->set() operation
70 * @ops: Filesystem specific getacl and setacl callbacks
71 */
72int
73generic_acl_set(struct inode *inode, struct generic_acl_operations *ops,
74        int type, const void *value, size_t size)
75{
76    struct posix_acl *acl = NULL;
77    int error;
78
79    if (S_ISLNK(inode->i_mode))
80        return -EOPNOTSUPP;
81    if (!is_owner_or_cap(inode))
82        return -EPERM;
83    if (value) {
84        acl = posix_acl_from_xattr(value, size);
85        if (IS_ERR(acl))
86            return PTR_ERR(acl);
87    }
88    if (acl) {
89        mode_t mode;
90
91        error = posix_acl_valid(acl);
92        if (error)
93            goto failed;
94        switch(type) {
95            case ACL_TYPE_ACCESS:
96                mode = inode->i_mode;
97                error = posix_acl_equiv_mode(acl, &mode);
98                if (error < 0)
99                    goto failed;
100                inode->i_mode = mode;
101                if (error == 0) {
102                    posix_acl_release(acl);
103                    acl = NULL;
104                }
105                break;
106
107            case ACL_TYPE_DEFAULT:
108                if (!S_ISDIR(inode->i_mode)) {
109                    error = -EINVAL;
110                    goto failed;
111                }
112                break;
113        }
114    }
115    ops->setacl(inode, type, acl);
116    error = 0;
117failed:
118    posix_acl_release(acl);
119    return error;
120}
121
122/**
123 * generic_acl_init - Take care of acl inheritance at @inode create time
124 * @ops: Filesystem specific getacl and setacl callbacks
125 *
126 * Files created inside a directory with a default ACL inherit the
127 * directory's default ACL.
128 */
129int
130generic_acl_init(struct inode *inode, struct inode *dir,
131         struct generic_acl_operations *ops)
132{
133    struct posix_acl *acl = NULL;
134    mode_t mode = inode->i_mode;
135    int error;
136
137    inode->i_mode = mode & ~current_umask();
138    if (!S_ISLNK(inode->i_mode))
139        acl = ops->getacl(dir, ACL_TYPE_DEFAULT);
140    if (acl) {
141        struct posix_acl *clone;
142
143        if (S_ISDIR(inode->i_mode)) {
144            clone = posix_acl_clone(acl, GFP_KERNEL);
145            error = -ENOMEM;
146            if (!clone)
147                goto cleanup;
148            ops->setacl(inode, ACL_TYPE_DEFAULT, clone);
149            posix_acl_release(clone);
150        }
151        clone = posix_acl_clone(acl, GFP_KERNEL);
152        error = -ENOMEM;
153        if (!clone)
154            goto cleanup;
155        error = posix_acl_create_masq(clone, &mode);
156        if (error >= 0) {
157            inode->i_mode = mode;
158            if (error > 0)
159                ops->setacl(inode, ACL_TYPE_ACCESS, clone);
160        }
161        posix_acl_release(clone);
162    }
163    error = 0;
164
165cleanup:
166    posix_acl_release(acl);
167    return error;
168}
169
170/**
171 * generic_acl_chmod - change the access acl of @inode upon chmod()
172 * @ops: FIlesystem specific getacl and setacl callbacks
173 *
174 * A chmod also changes the permissions of the owner, group/mask, and
175 * other ACL entries.
176 */
177int
178generic_acl_chmod(struct inode *inode, struct generic_acl_operations *ops)
179{
180    struct posix_acl *acl, *clone;
181    int error = 0;
182
183    if (S_ISLNK(inode->i_mode))
184        return -EOPNOTSUPP;
185    acl = ops->getacl(inode, ACL_TYPE_ACCESS);
186    if (acl) {
187        clone = posix_acl_clone(acl, GFP_KERNEL);
188        posix_acl_release(acl);
189        if (!clone)
190            return -ENOMEM;
191        error = posix_acl_chmod_masq(clone, inode->i_mode);
192        if (!error)
193            ops->setacl(inode, ACL_TYPE_ACCESS, clone);
194        posix_acl_release(clone);
195    }
196    return error;
197}
198

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