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[/] [test_project/] [trunk/] [linux_sd_driver/] [fs/] [ext3/] [acl.c] - Blame information for rev 62

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1 62 marcus.erl
/*
2
 * linux/fs/ext3/acl.c
3
 *
4
 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5
 */
6
 
7
#include <linux/init.h>
8
#include <linux/sched.h>
9
#include <linux/slab.h>
10
#include <linux/capability.h>
11
#include <linux/fs.h>
12
#include <linux/ext3_jbd.h>
13
#include <linux/ext3_fs.h>
14
#include "xattr.h"
15
#include "acl.h"
16
 
17
/*
18
 * Convert from filesystem to in-memory representation.
19
 */
20
static struct posix_acl *
21
ext3_acl_from_disk(const void *value, size_t size)
22
{
23
        const char *end = (char *)value + size;
24
        int n, count;
25
        struct posix_acl *acl;
26
 
27
        if (!value)
28
                return NULL;
29
        if (size < sizeof(ext3_acl_header))
30
                 return ERR_PTR(-EINVAL);
31
        if (((ext3_acl_header *)value)->a_version !=
32
            cpu_to_le32(EXT3_ACL_VERSION))
33
                return ERR_PTR(-EINVAL);
34
        value = (char *)value + sizeof(ext3_acl_header);
35
        count = ext3_acl_count(size);
36
        if (count < 0)
37
                return ERR_PTR(-EINVAL);
38
        if (count == 0)
39
                return NULL;
40
        acl = posix_acl_alloc(count, GFP_KERNEL);
41
        if (!acl)
42
                return ERR_PTR(-ENOMEM);
43
        for (n=0; n < count; n++) {
44
                ext3_acl_entry *entry =
45
                        (ext3_acl_entry *)value;
46
                if ((char *)value + sizeof(ext3_acl_entry_short) > end)
47
                        goto fail;
48
                acl->a_entries[n].e_tag  = le16_to_cpu(entry->e_tag);
49
                acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
50
                switch(acl->a_entries[n].e_tag) {
51
                        case ACL_USER_OBJ:
52
                        case ACL_GROUP_OBJ:
53
                        case ACL_MASK:
54
                        case ACL_OTHER:
55
                                value = (char *)value +
56
                                        sizeof(ext3_acl_entry_short);
57
                                acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
58
                                break;
59
 
60
                        case ACL_USER:
61
                        case ACL_GROUP:
62
                                value = (char *)value + sizeof(ext3_acl_entry);
63
                                if ((char *)value > end)
64
                                        goto fail;
65
                                acl->a_entries[n].e_id =
66
                                        le32_to_cpu(entry->e_id);
67
                                break;
68
 
69
                        default:
70
                                goto fail;
71
                }
72
        }
73
        if (value != end)
74
                goto fail;
75
        return acl;
76
 
77
fail:
78
        posix_acl_release(acl);
79
        return ERR_PTR(-EINVAL);
80
}
81
 
82
/*
83
 * Convert from in-memory to filesystem representation.
84
 */
85
static void *
86
ext3_acl_to_disk(const struct posix_acl *acl, size_t *size)
87
{
88
        ext3_acl_header *ext_acl;
89
        char *e;
90
        size_t n;
91
 
92
        *size = ext3_acl_size(acl->a_count);
93
        ext_acl = kmalloc(sizeof(ext3_acl_header) + acl->a_count *
94
                        sizeof(ext3_acl_entry), GFP_KERNEL);
95
        if (!ext_acl)
96
                return ERR_PTR(-ENOMEM);
97
        ext_acl->a_version = cpu_to_le32(EXT3_ACL_VERSION);
98
        e = (char *)ext_acl + sizeof(ext3_acl_header);
99
        for (n=0; n < acl->a_count; n++) {
100
                ext3_acl_entry *entry = (ext3_acl_entry *)e;
101
                entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
102
                entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
103
                switch(acl->a_entries[n].e_tag) {
104
                        case ACL_USER:
105
                        case ACL_GROUP:
106
                                entry->e_id =
107
                                        cpu_to_le32(acl->a_entries[n].e_id);
108
                                e += sizeof(ext3_acl_entry);
109
                                break;
110
 
111
                        case ACL_USER_OBJ:
112
                        case ACL_GROUP_OBJ:
113
                        case ACL_MASK:
114
                        case ACL_OTHER:
115
                                e += sizeof(ext3_acl_entry_short);
116
                                break;
117
 
118
                        default:
119
                                goto fail;
120
                }
121
        }
122
        return (char *)ext_acl;
123
 
124
fail:
125
        kfree(ext_acl);
126
        return ERR_PTR(-EINVAL);
127
}
128
 
129
static inline struct posix_acl *
130
ext3_iget_acl(struct inode *inode, struct posix_acl **i_acl)
131
{
132
        struct posix_acl *acl = EXT3_ACL_NOT_CACHED;
133
 
134
        spin_lock(&inode->i_lock);
135
        if (*i_acl != EXT3_ACL_NOT_CACHED)
136
                acl = posix_acl_dup(*i_acl);
137
        spin_unlock(&inode->i_lock);
138
 
139
        return acl;
140
}
141
 
142
static inline void
143
ext3_iset_acl(struct inode *inode, struct posix_acl **i_acl,
144
                  struct posix_acl *acl)
145
{
146
        spin_lock(&inode->i_lock);
147
        if (*i_acl != EXT3_ACL_NOT_CACHED)
148
                posix_acl_release(*i_acl);
149
        *i_acl = posix_acl_dup(acl);
150
        spin_unlock(&inode->i_lock);
151
}
152
 
153
/*
154
 * Inode operation get_posix_acl().
155
 *
156
 * inode->i_mutex: don't care
157
 */
158
static struct posix_acl *
159
ext3_get_acl(struct inode *inode, int type)
160
{
161
        struct ext3_inode_info *ei = EXT3_I(inode);
162
        int name_index;
163
        char *value = NULL;
164
        struct posix_acl *acl;
165
        int retval;
166
 
167
        if (!test_opt(inode->i_sb, POSIX_ACL))
168
                return NULL;
169
 
170
        switch(type) {
171
                case ACL_TYPE_ACCESS:
172
                        acl = ext3_iget_acl(inode, &ei->i_acl);
173
                        if (acl != EXT3_ACL_NOT_CACHED)
174
                                return acl;
175
                        name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
176
                        break;
177
 
178
                case ACL_TYPE_DEFAULT:
179
                        acl = ext3_iget_acl(inode, &ei->i_default_acl);
180
                        if (acl != EXT3_ACL_NOT_CACHED)
181
                                return acl;
182
                        name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
183
                        break;
184
 
185
                default:
186
                        return ERR_PTR(-EINVAL);
187
        }
188
        retval = ext3_xattr_get(inode, name_index, "", NULL, 0);
189
        if (retval > 0) {
190
                value = kmalloc(retval, GFP_KERNEL);
191
                if (!value)
192
                        return ERR_PTR(-ENOMEM);
193
                retval = ext3_xattr_get(inode, name_index, "", value, retval);
194
        }
195
        if (retval > 0)
196
                acl = ext3_acl_from_disk(value, retval);
197
        else if (retval == -ENODATA || retval == -ENOSYS)
198
                acl = NULL;
199
        else
200
                acl = ERR_PTR(retval);
201
        kfree(value);
202
 
203
        if (!IS_ERR(acl)) {
204
                switch(type) {
205
                        case ACL_TYPE_ACCESS:
206
                                ext3_iset_acl(inode, &ei->i_acl, acl);
207
                                break;
208
 
209
                        case ACL_TYPE_DEFAULT:
210
                                ext3_iset_acl(inode, &ei->i_default_acl, acl);
211
                                break;
212
                }
213
        }
214
        return acl;
215
}
216
 
217
/*
218
 * Set the access or default ACL of an inode.
219
 *
220
 * inode->i_mutex: down unless called from ext3_new_inode
221
 */
222
static int
223
ext3_set_acl(handle_t *handle, struct inode *inode, int type,
224
             struct posix_acl *acl)
225
{
226
        struct ext3_inode_info *ei = EXT3_I(inode);
227
        int name_index;
228
        void *value = NULL;
229
        size_t size = 0;
230
        int error;
231
 
232
        if (S_ISLNK(inode->i_mode))
233
                return -EOPNOTSUPP;
234
 
235
        switch(type) {
236
                case ACL_TYPE_ACCESS:
237
                        name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
238
                        if (acl) {
239
                                mode_t mode = inode->i_mode;
240
                                error = posix_acl_equiv_mode(acl, &mode);
241
                                if (error < 0)
242
                                        return error;
243
                                else {
244
                                        inode->i_mode = mode;
245
                                        ext3_mark_inode_dirty(handle, inode);
246
                                        if (error == 0)
247
                                                acl = NULL;
248
                                }
249
                        }
250
                        break;
251
 
252
                case ACL_TYPE_DEFAULT:
253
                        name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
254
                        if (!S_ISDIR(inode->i_mode))
255
                                return acl ? -EACCES : 0;
256
                        break;
257
 
258
                default:
259
                        return -EINVAL;
260
        }
261
        if (acl) {
262
                value = ext3_acl_to_disk(acl, &size);
263
                if (IS_ERR(value))
264
                        return (int)PTR_ERR(value);
265
        }
266
 
267
        error = ext3_xattr_set_handle(handle, inode, name_index, "",
268
                                      value, size, 0);
269
 
270
        kfree(value);
271
        if (!error) {
272
                switch(type) {
273
                        case ACL_TYPE_ACCESS:
274
                                ext3_iset_acl(inode, &ei->i_acl, acl);
275
                                break;
276
 
277
                        case ACL_TYPE_DEFAULT:
278
                                ext3_iset_acl(inode, &ei->i_default_acl, acl);
279
                                break;
280
                }
281
        }
282
        return error;
283
}
284
 
285
static int
286
ext3_check_acl(struct inode *inode, int mask)
287
{
288
        struct posix_acl *acl = ext3_get_acl(inode, ACL_TYPE_ACCESS);
289
 
290
        if (IS_ERR(acl))
291
                return PTR_ERR(acl);
292
        if (acl) {
293
                int error = posix_acl_permission(inode, acl, mask);
294
                posix_acl_release(acl);
295
                return error;
296
        }
297
 
298
        return -EAGAIN;
299
}
300
 
301
int
302
ext3_permission(struct inode *inode, int mask, struct nameidata *nd)
303
{
304
        return generic_permission(inode, mask, ext3_check_acl);
305
}
306
 
307
/*
308
 * Initialize the ACLs of a new inode. Called from ext3_new_inode.
309
 *
310
 * dir->i_mutex: down
311
 * inode->i_mutex: up (access to inode is still exclusive)
312
 */
313
int
314
ext3_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
315
{
316
        struct posix_acl *acl = NULL;
317
        int error = 0;
318
 
319
        if (!S_ISLNK(inode->i_mode)) {
320
                if (test_opt(dir->i_sb, POSIX_ACL)) {
321
                        acl = ext3_get_acl(dir, ACL_TYPE_DEFAULT);
322
                        if (IS_ERR(acl))
323
                                return PTR_ERR(acl);
324
                }
325
                if (!acl)
326
                        inode->i_mode &= ~current->fs->umask;
327
        }
328
        if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
329
                struct posix_acl *clone;
330
                mode_t mode;
331
 
332
                if (S_ISDIR(inode->i_mode)) {
333
                        error = ext3_set_acl(handle, inode,
334
                                             ACL_TYPE_DEFAULT, acl);
335
                        if (error)
336
                                goto cleanup;
337
                }
338
                clone = posix_acl_clone(acl, GFP_KERNEL);
339
                error = -ENOMEM;
340
                if (!clone)
341
                        goto cleanup;
342
 
343
                mode = inode->i_mode;
344
                error = posix_acl_create_masq(clone, &mode);
345
                if (error >= 0) {
346
                        inode->i_mode = mode;
347
                        if (error > 0) {
348
                                /* This is an extended ACL */
349
                                error = ext3_set_acl(handle, inode,
350
                                                     ACL_TYPE_ACCESS, clone);
351
                        }
352
                }
353
                posix_acl_release(clone);
354
        }
355
cleanup:
356
        posix_acl_release(acl);
357
        return error;
358
}
359
 
360
/*
361
 * Does chmod for an inode that may have an Access Control List. The
362
 * inode->i_mode field must be updated to the desired value by the caller
363
 * before calling this function.
364
 * Returns 0 on success, or a negative error number.
365
 *
366
 * We change the ACL rather than storing some ACL entries in the file
367
 * mode permission bits (which would be more efficient), because that
368
 * would break once additional permissions (like  ACL_APPEND, ACL_DELETE
369
 * for directories) are added. There are no more bits available in the
370
 * file mode.
371
 *
372
 * inode->i_mutex: down
373
 */
374
int
375
ext3_acl_chmod(struct inode *inode)
376
{
377
        struct posix_acl *acl, *clone;
378
        int error;
379
 
380
        if (S_ISLNK(inode->i_mode))
381
                return -EOPNOTSUPP;
382
        if (!test_opt(inode->i_sb, POSIX_ACL))
383
                return 0;
384
        acl = ext3_get_acl(inode, ACL_TYPE_ACCESS);
385
        if (IS_ERR(acl) || !acl)
386
                return PTR_ERR(acl);
387
        clone = posix_acl_clone(acl, GFP_KERNEL);
388
        posix_acl_release(acl);
389
        if (!clone)
390
                return -ENOMEM;
391
        error = posix_acl_chmod_masq(clone, inode->i_mode);
392
        if (!error) {
393
                handle_t *handle;
394
                int retries = 0;
395
 
396
        retry:
397
                handle = ext3_journal_start(inode,
398
                                EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
399
                if (IS_ERR(handle)) {
400
                        error = PTR_ERR(handle);
401
                        ext3_std_error(inode->i_sb, error);
402
                        goto out;
403
                }
404
                error = ext3_set_acl(handle, inode, ACL_TYPE_ACCESS, clone);
405
                ext3_journal_stop(handle);
406
                if (error == -ENOSPC &&
407
                    ext3_should_retry_alloc(inode->i_sb, &retries))
408
                        goto retry;
409
        }
410
out:
411
        posix_acl_release(clone);
412
        return error;
413
}
414
 
415
/*
416
 * Extended attribute handlers
417
 */
418
static size_t
419
ext3_xattr_list_acl_access(struct inode *inode, char *list, size_t list_len,
420
                           const char *name, size_t name_len)
421
{
422
        const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
423
 
424
        if (!test_opt(inode->i_sb, POSIX_ACL))
425
                return 0;
426
        if (list && size <= list_len)
427
                memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
428
        return size;
429
}
430
 
431
static size_t
432
ext3_xattr_list_acl_default(struct inode *inode, char *list, size_t list_len,
433
                            const char *name, size_t name_len)
434
{
435
        const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
436
 
437
        if (!test_opt(inode->i_sb, POSIX_ACL))
438
                return 0;
439
        if (list && size <= list_len)
440
                memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
441
        return size;
442
}
443
 
444
static int
445
ext3_xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
446
{
447
        struct posix_acl *acl;
448
        int error;
449
 
450
        if (!test_opt(inode->i_sb, POSIX_ACL))
451
                return -EOPNOTSUPP;
452
 
453
        acl = ext3_get_acl(inode, type);
454
        if (IS_ERR(acl))
455
                return PTR_ERR(acl);
456
        if (acl == NULL)
457
                return -ENODATA;
458
        error = posix_acl_to_xattr(acl, buffer, size);
459
        posix_acl_release(acl);
460
 
461
        return error;
462
}
463
 
464
static int
465
ext3_xattr_get_acl_access(struct inode *inode, const char *name,
466
                          void *buffer, size_t size)
467
{
468
        if (strcmp(name, "") != 0)
469
                return -EINVAL;
470
        return ext3_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
471
}
472
 
473
static int
474
ext3_xattr_get_acl_default(struct inode *inode, const char *name,
475
                           void *buffer, size_t size)
476
{
477
        if (strcmp(name, "") != 0)
478
                return -EINVAL;
479
        return ext3_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
480
}
481
 
482
static int
483
ext3_xattr_set_acl(struct inode *inode, int type, const void *value,
484
                   size_t size)
485
{
486
        handle_t *handle;
487
        struct posix_acl *acl;
488
        int error, retries = 0;
489
 
490
        if (!test_opt(inode->i_sb, POSIX_ACL))
491
                return -EOPNOTSUPP;
492
        if (!is_owner_or_cap(inode))
493
                return -EPERM;
494
 
495
        if (value) {
496
                acl = posix_acl_from_xattr(value, size);
497
                if (IS_ERR(acl))
498
                        return PTR_ERR(acl);
499
                else if (acl) {
500
                        error = posix_acl_valid(acl);
501
                        if (error)
502
                                goto release_and_out;
503
                }
504
        } else
505
                acl = NULL;
506
 
507
retry:
508
        handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
509
        if (IS_ERR(handle))
510
                return PTR_ERR(handle);
511
        error = ext3_set_acl(handle, inode, type, acl);
512
        ext3_journal_stop(handle);
513
        if (error == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
514
                goto retry;
515
 
516
release_and_out:
517
        posix_acl_release(acl);
518
        return error;
519
}
520
 
521
static int
522
ext3_xattr_set_acl_access(struct inode *inode, const char *name,
523
                          const void *value, size_t size, int flags)
524
{
525
        if (strcmp(name, "") != 0)
526
                return -EINVAL;
527
        return ext3_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
528
}
529
 
530
static int
531
ext3_xattr_set_acl_default(struct inode *inode, const char *name,
532
                           const void *value, size_t size, int flags)
533
{
534
        if (strcmp(name, "") != 0)
535
                return -EINVAL;
536
        return ext3_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
537
}
538
 
539
struct xattr_handler ext3_xattr_acl_access_handler = {
540
        .prefix = POSIX_ACL_XATTR_ACCESS,
541
        .list   = ext3_xattr_list_acl_access,
542
        .get    = ext3_xattr_get_acl_access,
543
        .set    = ext3_xattr_set_acl_access,
544
};
545
 
546
struct xattr_handler ext3_xattr_acl_default_handler = {
547
        .prefix = POSIX_ACL_XATTR_DEFAULT,
548
        .list   = ext3_xattr_list_acl_default,
549
        .get    = ext3_xattr_get_acl_default,
550
        .set    = ext3_xattr_set_acl_default,
551
};

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