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 (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
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->fs->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