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-rw-r--r--drivers/mtd/ubi/cdev.c722
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diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
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1/*
2 * Copyright (c) International Business Machines Corp., 2006
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
12 * the GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17 *
18 * Author: Artem Bityutskiy (Битюцкий Артём)
19 */
20
21/*
22 * This file includes implementation of UBI character device operations.
23 *
24 * There are two kinds of character devices in UBI: UBI character devices and
25 * UBI volume character devices. UBI character devices allow users to
26 * manipulate whole volumes: create, remove, and re-size them. Volume character
27 * devices provide volume I/O capabilities.
28 *
29 * Major and minor numbers are assigned dynamically to both UBI and volume
30 * character devices.
31 */
32
33#include <linux/module.h>
34#include <linux/stat.h>
35#include <linux/ioctl.h>
36#include <linux/capability.h>
37#include <mtd/ubi-user.h>
38#include <asm/uaccess.h>
39#include <asm/div64.h>
40#include "ubi.h"
41
42/*
43 * Maximum sequence numbers of UBI and volume character device IOCTLs (direct
44 * logical eraseblock erase is a debug-only feature).
45 */
46#define UBI_CDEV_IOC_MAX_SEQ 2
47#ifndef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO
48#define VOL_CDEV_IOC_MAX_SEQ 1
49#else
50#define VOL_CDEV_IOC_MAX_SEQ 2
51#endif
52
53/**
54 * major_to_device - get UBI device object by character device major number.
55 * @major: major number
56 *
57 * This function returns a pointer to the UBI device object.
58 */
59static struct ubi_device *major_to_device(int major)
60{
61 int i;
62
63 for (i = 0; i < ubi_devices_cnt; i++)
64 if (ubi_devices[i] && ubi_devices[i]->major == major)
65 return ubi_devices[i];
66 BUG();
67}
68
69/**
70 * get_exclusive - get exclusive access to an UBI volume.
71 * @desc: volume descriptor
72 *
73 * This function changes UBI volume open mode to "exclusive". Returns previous
74 * mode value (positive integer) in case of success and a negative error code
75 * in case of failure.
76 */
77static int get_exclusive(struct ubi_volume_desc *desc)
78{
79 int users, err;
80 struct ubi_volume *vol = desc->vol;
81
82 spin_lock(&vol->ubi->volumes_lock);
83 users = vol->readers + vol->writers + vol->exclusive;
84 ubi_assert(users > 0);
85 if (users > 1) {
86 dbg_err("%d users for volume %d", users, vol->vol_id);
87 err = -EBUSY;
88 } else {
89 vol->readers = vol->writers = 0;
90 vol->exclusive = 1;
91 err = desc->mode;
92 desc->mode = UBI_EXCLUSIVE;
93 }
94 spin_unlock(&vol->ubi->volumes_lock);
95
96 return err;
97}
98
99/**
100 * revoke_exclusive - revoke exclusive mode.
101 * @desc: volume descriptor
102 * @mode: new mode to switch to
103 */
104static void revoke_exclusive(struct ubi_volume_desc *desc, int mode)
105{
106 struct ubi_volume *vol = desc->vol;
107
108 spin_lock(&vol->ubi->volumes_lock);
109 ubi_assert(vol->readers == 0 && vol->writers == 0);
110 ubi_assert(vol->exclusive == 1 && desc->mode == UBI_EXCLUSIVE);
111 vol->exclusive = 0;
112 if (mode == UBI_READONLY)
113 vol->readers = 1;
114 else if (mode == UBI_READWRITE)
115 vol->writers = 1;
116 else
117 vol->exclusive = 1;
118 spin_unlock(&vol->ubi->volumes_lock);
119
120 desc->mode = mode;
121}
122
123static int vol_cdev_open(struct inode *inode, struct file *file)
124{
125 struct ubi_volume_desc *desc;
126 const struct ubi_device *ubi = major_to_device(imajor(inode));
127 int vol_id = iminor(inode) - 1;
128 int mode;
129
130 if (file->f_mode & FMODE_WRITE)
131 mode = UBI_READWRITE;
132 else
133 mode = UBI_READONLY;
134
135 dbg_msg("open volume %d, mode %d", vol_id, mode);
136
137 desc = ubi_open_volume(ubi->ubi_num, vol_id, mode);
138 if (IS_ERR(desc))
139 return PTR_ERR(desc);
140
141 file->private_data = desc;
142 return 0;
143}
144
145static int vol_cdev_release(struct inode *inode, struct file *file)
146{
147 struct ubi_volume_desc *desc = file->private_data;
148 struct ubi_volume *vol = desc->vol;
149
150 dbg_msg("release volume %d, mode %d", vol->vol_id, desc->mode);
151
152 if (vol->updating) {
153 ubi_warn("update of volume %d not finished, volume is damaged",
154 vol->vol_id);
155 vol->updating = 0;
156 kfree(vol->upd_buf);
157 }
158
159 ubi_close_volume(desc);
160 return 0;
161}
162
163static loff_t vol_cdev_llseek(struct file *file, loff_t offset, int origin)
164{
165 struct ubi_volume_desc *desc = file->private_data;
166 struct ubi_volume *vol = desc->vol;
167 loff_t new_offset;
168
169 if (vol->updating) {
170 /* Update is in progress, seeking is prohibited */
171 dbg_err("updating");
172 return -EBUSY;
173 }
174
175 switch (origin) {
176 case 0: /* SEEK_SET */
177 new_offset = offset;
178 break;
179 case 1: /* SEEK_CUR */
180 new_offset = file->f_pos + offset;
181 break;
182 case 2: /* SEEK_END */
183 new_offset = vol->used_bytes + offset;
184 break;
185 default:
186 return -EINVAL;
187 }
188
189 if (new_offset < 0 || new_offset > vol->used_bytes) {
190 dbg_err("bad seek %lld", new_offset);
191 return -EINVAL;
192 }
193
194 dbg_msg("seek volume %d, offset %lld, origin %d, new offset %lld",
195 vol->vol_id, offset, origin, new_offset);
196
197 file->f_pos = new_offset;
198 return new_offset;
199}
200
201static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
202 loff_t *offp)
203{
204 struct ubi_volume_desc *desc = file->private_data;
205 struct ubi_volume *vol = desc->vol;
206 struct ubi_device *ubi = vol->ubi;
207 int err, lnum, off, len, vol_id = desc->vol->vol_id, tbuf_size;
208 size_t count_save = count;
209 void *tbuf;
210 uint64_t tmp;
211
212 dbg_msg("read %zd bytes from offset %lld of volume %d",
213 count, *offp, vol_id);
214
215 if (vol->updating) {
216 dbg_err("updating");
217 return -EBUSY;
218 }
219 if (vol->upd_marker) {
220 dbg_err("damaged volume, update marker is set");
221 return -EBADF;
222 }
223 if (*offp == vol->used_bytes || count == 0)
224 return 0;
225
226 if (vol->corrupted)
227 dbg_msg("read from corrupted volume %d", vol_id);
228
229 if (*offp + count > vol->used_bytes)
230 count_save = count = vol->used_bytes - *offp;
231
232 tbuf_size = vol->usable_leb_size;
233 if (count < tbuf_size)
234 tbuf_size = ALIGN(count, ubi->min_io_size);
235 tbuf = kmalloc(tbuf_size, GFP_KERNEL);
236 if (!tbuf)
237 return -ENOMEM;
238
239 len = count > tbuf_size ? tbuf_size : count;
240
241 tmp = *offp;
242 off = do_div(tmp, vol->usable_leb_size);
243 lnum = tmp;
244
245 do {
246 cond_resched();
247
248 if (off + len >= vol->usable_leb_size)
249 len = vol->usable_leb_size - off;
250
251 err = ubi_eba_read_leb(ubi, vol_id, lnum, tbuf, off, len, 0);
252 if (err)
253 break;
254
255 off += len;
256 if (off == vol->usable_leb_size) {
257 lnum += 1;
258 off -= vol->usable_leb_size;
259 }
260
261 count -= len;
262 *offp += len;
263
264 err = copy_to_user(buf, tbuf, len);
265 if (err) {
266 err = -EFAULT;
267 break;
268 }
269
270 buf += len;
271 len = count > tbuf_size ? tbuf_size : count;
272 } while (count);
273
274 kfree(tbuf);
275 return err ? err : count_save - count;
276}
277
278#ifdef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO
279
280/*
281 * This function allows to directly write to dynamic UBI volumes, without
282 * issuing the volume update operation. Available only as a debugging feature.
283 * Very useful for testing UBI.
284 */
285static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
286 size_t count, loff_t *offp)
287{
288 struct ubi_volume_desc *desc = file->private_data;
289 struct ubi_volume *vol = desc->vol;
290 struct ubi_device *ubi = vol->ubi;
291 int lnum, off, len, tbuf_size, vol_id = vol->vol_id, err = 0;
292 size_t count_save = count;
293 char *tbuf;
294 uint64_t tmp;
295
296 dbg_msg("requested: write %zd bytes to offset %lld of volume %u",
297 count, *offp, desc->vol->vol_id);
298
299 if (vol->vol_type == UBI_STATIC_VOLUME)
300 return -EROFS;
301
302 tmp = *offp;
303 off = do_div(tmp, vol->usable_leb_size);
304 lnum = tmp;
305
306 if (off % ubi->min_io_size) {
307 dbg_err("unaligned position");
308 return -EINVAL;
309 }
310
311 if (*offp + count > vol->used_bytes)
312 count_save = count = vol->used_bytes - *offp;
313
314 /* We can write only in fractions of the minimum I/O unit */
315 if (count % ubi->min_io_size) {
316 dbg_err("unaligned write length");
317 return -EINVAL;
318 }
319
320 tbuf_size = vol->usable_leb_size;
321 if (count < tbuf_size)
322 tbuf_size = ALIGN(count, ubi->min_io_size);
323 tbuf = kmalloc(tbuf_size, GFP_KERNEL);
324 if (!tbuf)
325 return -ENOMEM;
326
327 len = count > tbuf_size ? tbuf_size : count;
328
329 while (count) {
330 cond_resched();
331
332 if (off + len >= vol->usable_leb_size)
333 len = vol->usable_leb_size - off;
334
335 err = copy_from_user(tbuf, buf, len);
336 if (err) {
337 err = -EFAULT;
338 break;
339 }
340
341 err = ubi_eba_write_leb(ubi, vol_id, lnum, tbuf, off, len,
342 UBI_UNKNOWN);
343 if (err)
344 break;
345
346 off += len;
347 if (off == vol->usable_leb_size) {
348 lnum += 1;
349 off -= vol->usable_leb_size;
350 }
351
352 count -= len;
353 *offp += len;
354 buf += len;
355 len = count > tbuf_size ? tbuf_size : count;
356 }
357
358 kfree(tbuf);
359 return err ? err : count_save - count;
360}
361
362#else
363#define vol_cdev_direct_write(file, buf, count, offp) -EPERM
364#endif /* CONFIG_MTD_UBI_DEBUG_USERSPACE_IO */
365
366static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
367 size_t count, loff_t *offp)
368{
369 int err = 0;
370 struct ubi_volume_desc *desc = file->private_data;
371 struct ubi_volume *vol = desc->vol;
372 struct ubi_device *ubi = vol->ubi;
373
374 if (!vol->updating)
375 return vol_cdev_direct_write(file, buf, count, offp);
376
377 err = ubi_more_update_data(ubi, vol->vol_id, buf, count);
378 if (err < 0) {
379 ubi_err("cannot write %zd bytes of update data", count);
380 return err;
381 }
382
383 if (err) {
384 /*
385 * Update is finished, @err contains number of actually written
386 * bytes now.
387 */
388 count = err;
389
390 err = ubi_check_volume(ubi, vol->vol_id);
391 if (err < 0)
392 return err;
393
394 if (err) {
395 ubi_warn("volume %d on UBI device %d is corrupted",
396 vol->vol_id, ubi->ubi_num);
397 vol->corrupted = 1;
398 }
399 vol->checked = 1;
400 revoke_exclusive(desc, UBI_READWRITE);
401 }
402
403 *offp += count;
404 return count;
405}
406
407static int vol_cdev_ioctl(struct inode *inode, struct file *file,
408 unsigned int cmd, unsigned long arg)
409{
410 int err = 0;
411 struct ubi_volume_desc *desc = file->private_data;
412 struct ubi_volume *vol = desc->vol;
413 struct ubi_device *ubi = vol->ubi;
414 void __user *argp = (void __user *)arg;
415
416 if (_IOC_NR(cmd) > VOL_CDEV_IOC_MAX_SEQ ||
417 _IOC_TYPE(cmd) != UBI_VOL_IOC_MAGIC)
418 return -ENOTTY;
419
420 if (_IOC_DIR(cmd) && _IOC_READ)
421 err = !access_ok(VERIFY_WRITE, argp, _IOC_SIZE(cmd));
422 else if (_IOC_DIR(cmd) && _IOC_WRITE)
423 err = !access_ok(VERIFY_READ, argp, _IOC_SIZE(cmd));
424 if (err)
425 return -EFAULT;
426
427 switch (cmd) {
428
429 /* Volume update command */
430 case UBI_IOCVOLUP:
431 {
432 int64_t bytes, rsvd_bytes;
433
434 if (!capable(CAP_SYS_RESOURCE)) {
435 err = -EPERM;
436 break;
437 }
438
439 err = copy_from_user(&bytes, argp, sizeof(int64_t));
440 if (err) {
441 err = -EFAULT;
442 break;
443 }
444
445 if (desc->mode == UBI_READONLY) {
446 err = -EROFS;
447 break;
448 }
449
450 rsvd_bytes = vol->reserved_pebs * (ubi->leb_size-vol->data_pad);
451 if (bytes < 0 || bytes > rsvd_bytes) {
452 err = -EINVAL;
453 break;
454 }
455
456 err = get_exclusive(desc);
457 if (err < 0)
458 break;
459
460 err = ubi_start_update(ubi, vol->vol_id, bytes);
461 if (bytes == 0)
462 revoke_exclusive(desc, UBI_READWRITE);
463
464 file->f_pos = 0;
465 break;
466 }
467
468#ifdef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO
469 /* Logical eraseblock erasure command */
470 case UBI_IOCEBER:
471 {
472 int32_t lnum;
473
474 err = __get_user(lnum, (__user int32_t *)argp);
475 if (err) {
476 err = -EFAULT;
477 break;
478 }
479
480 if (desc->mode == UBI_READONLY) {
481 err = -EROFS;
482 break;
483 }
484
485 if (lnum < 0 || lnum >= vol->reserved_pebs) {
486 err = -EINVAL;
487 break;
488 }
489
490 if (vol->vol_type != UBI_DYNAMIC_VOLUME) {
491 err = -EROFS;
492 break;
493 }
494
495 dbg_msg("erase LEB %d:%d", vol->vol_id, lnum);
496 err = ubi_eba_unmap_leb(ubi, vol->vol_id, lnum);
497 if (err)
498 break;
499
500 err = ubi_wl_flush(ubi);
501 break;
502 }
503#endif
504
505 default:
506 err = -ENOTTY;
507 break;
508 }
509
510 return err;
511}
512
513/**
514 * verify_mkvol_req - verify volume creation request.
515 * @ubi: UBI device description object
516 * @req: the request to check
517 *
518 * This function zero if the request is correct, and %-EINVAL if not.
519 */
520static int verify_mkvol_req(const struct ubi_device *ubi,
521 const struct ubi_mkvol_req *req)
522{
523 int n, err = -EINVAL;
524
525 if (req->bytes < 0 || req->alignment < 0 || req->vol_type < 0 ||
526 req->name_len < 0)
527 goto bad;
528
529 if ((req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) &&
530 req->vol_id != UBI_VOL_NUM_AUTO)
531 goto bad;
532
533 if (req->alignment == 0)
534 goto bad;
535
536 if (req->bytes == 0)
537 goto bad;
538
539 if (req->vol_type != UBI_DYNAMIC_VOLUME &&
540 req->vol_type != UBI_STATIC_VOLUME)
541 goto bad;
542
543 if (req->alignment > ubi->leb_size)
544 goto bad;
545
546 n = req->alignment % ubi->min_io_size;
547 if (req->alignment != 1 && n)
548 goto bad;
549
550 if (req->name_len > UBI_VOL_NAME_MAX) {
551 err = -ENAMETOOLONG;
552 goto bad;
553 }
554
555 return 0;
556
557bad:
558 dbg_err("bad volume creation request");
559 ubi_dbg_dump_mkvol_req(req);
560 return err;
561}
562
563/**
564 * verify_rsvol_req - verify volume re-size request.
565 * @ubi: UBI device description object
566 * @req: the request to check
567 *
568 * This function returns zero if the request is correct, and %-EINVAL if not.
569 */
570static int verify_rsvol_req(const struct ubi_device *ubi,
571 const struct ubi_rsvol_req *req)
572{
573 if (req->bytes <= 0)
574 return -EINVAL;
575
576 if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots)
577 return -EINVAL;
578
579 return 0;
580}
581
582static int ubi_cdev_ioctl(struct inode *inode, struct file *file,
583 unsigned int cmd, unsigned long arg)
584{
585 int err = 0;
586 struct ubi_device *ubi;
587 struct ubi_volume_desc *desc;
588 void __user *argp = (void __user *)arg;
589
590 if (_IOC_NR(cmd) > UBI_CDEV_IOC_MAX_SEQ ||
591 _IOC_TYPE(cmd) != UBI_IOC_MAGIC)
592 return -ENOTTY;
593
594 if (_IOC_DIR(cmd) && _IOC_READ)
595 err = !access_ok(VERIFY_WRITE, argp, _IOC_SIZE(cmd));
596 else if (_IOC_DIR(cmd) && _IOC_WRITE)
597 err = !access_ok(VERIFY_READ, argp, _IOC_SIZE(cmd));
598 if (err)
599 return -EFAULT;
600
601 if (!capable(CAP_SYS_RESOURCE))
602 return -EPERM;
603
604 ubi = major_to_device(imajor(inode));
605 if (IS_ERR(ubi))
606 return PTR_ERR(ubi);
607
608 switch (cmd) {
609 /* Create volume command */
610 case UBI_IOCMKVOL:
611 {
612 struct ubi_mkvol_req req;
613
614 dbg_msg("create volume");
615 err = __copy_from_user(&req, argp,
616 sizeof(struct ubi_mkvol_req));
617 if (err) {
618 err = -EFAULT;
619 break;
620 }
621
622 err = verify_mkvol_req(ubi, &req);
623 if (err)
624 break;
625
626 req.name[req.name_len] = '\0';
627
628 err = ubi_create_volume(ubi, &req);
629 if (err)
630 break;
631
632 err = __put_user(req.vol_id, (__user int32_t *)argp);
633 if (err)
634 err = -EFAULT;
635
636 break;
637 }
638
639 /* Remove volume command */
640 case UBI_IOCRMVOL:
641 {
642 int vol_id;
643
644 dbg_msg("remove volume");
645 err = __get_user(vol_id, (__user int32_t *)argp);
646 if (err) {
647 err = -EFAULT;
648 break;
649 }
650
651 desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
652 if (IS_ERR(desc)) {
653 err = PTR_ERR(desc);
654 break;
655 }
656
657 err = ubi_remove_volume(desc);
658 if (err)
659 ubi_close_volume(desc);
660
661 break;
662 }
663
664 /* Re-size volume command */
665 case UBI_IOCRSVOL:
666 {
667 int pebs;
668 uint64_t tmp;
669 struct ubi_rsvol_req req;
670
671 dbg_msg("re-size volume");
672 err = __copy_from_user(&req, argp,
673 sizeof(struct ubi_rsvol_req));
674 if (err) {
675 err = -EFAULT;
676 break;
677 }
678
679 err = verify_rsvol_req(ubi, &req);
680 if (err)
681 break;
682
683 desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
684 if (IS_ERR(desc)) {
685 err = PTR_ERR(desc);
686 break;
687 }
688
689 tmp = req.bytes;
690 pebs = !!do_div(tmp, desc->vol->usable_leb_size);
691 pebs += tmp;
692
693 err = ubi_resize_volume(desc, pebs);
694 ubi_close_volume(desc);
695 break;
696 }
697
698 default:
699 err = -ENOTTY;
700 break;
701 }
702
703 return err;
704}
705
706/* UBI character device operations */
707struct file_operations ubi_cdev_operations = {
708 .owner = THIS_MODULE,
709 .ioctl = ubi_cdev_ioctl,
710 .llseek = no_llseek
711};
712
713/* UBI volume character device operations */
714struct file_operations ubi_vol_cdev_operations = {
715 .owner = THIS_MODULE,
716 .open = vol_cdev_open,
717 .release = vol_cdev_release,
718 .llseek = vol_cdev_llseek,
719 .read = vol_cdev_read,
720 .write = vol_cdev_write,
721 .ioctl = vol_cdev_ioctl
722};