aboutsummaryrefslogtreecommitdiff
path: root/drivers/mtd/ubi/cdev.c
blob: 22c15a388f28947dab4a56a1f2991aa36a3b8270 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
/*
 * Copyright (c) International Business Machines Corp., 2006
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
 * the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Author: Artem Bityutskiy (Битюцкий Артём)
 */

/*
 * This file includes implementation of UBI character device operations.
 *
 * There are two kinds of character devices in UBI: UBI character devices and
 * UBI volume character devices. UBI character devices allow users to
 * manipulate whole volumes: create, remove, and re-size them. Volume character
 * devices provide volume I/O capabilities.
 *
 * Major and minor numbers are assigned dynamically to both UBI and volume
 * character devices.
 */

#include <linux/module.h>
#include <linux/stat.h>
#include <linux/ioctl.h>
#include <linux/capability.h>
#include <mtd/ubi-user.h>
#include <asm/uaccess.h>
#include <asm/div64.h>
#include "ubi.h"

/*
 * Maximum sequence numbers of UBI and volume character device IOCTLs (direct
 * logical eraseblock erase is a debug-only feature).
 */
#define UBI_CDEV_IOC_MAX_SEQ 2
#ifndef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO
#define VOL_CDEV_IOC_MAX_SEQ 1
#else
#define VOL_CDEV_IOC_MAX_SEQ 2
#endif

/**
 * major_to_device - get UBI device object by character device major number.
 * @major: major number
 *
 * This function returns a pointer to the UBI device object.
 */
static struct ubi_device *major_to_device(int major)
{
	int i;

	for (i = 0; i < UBI_MAX_DEVICES; i++)
		if (ubi_devices[i] && MAJOR(ubi_devices[i]->cdev.dev) == major)
			return ubi_devices[i];
	BUG();
	return NULL;
}

/**
 * get_exclusive - get exclusive access to an UBI volume.
 * @desc: volume descriptor
 *
 * This function changes UBI volume open mode to "exclusive". Returns previous
 * mode value (positive integer) in case of success and a negative error code
 * in case of failure.
 */
static int get_exclusive(struct ubi_volume_desc *desc)
{
	int users, err;
	struct ubi_volume *vol = desc->vol;

	spin_lock(&vol->ubi->volumes_lock);
	users = vol->readers + vol->writers + vol->exclusive;
	ubi_assert(users > 0);
	if (users > 1) {
		dbg_err("%d users for volume %d", users, vol->vol_id);
		err = -EBUSY;
	} else {
		vol->readers = vol->writers = 0;
		vol->exclusive = 1;
		err = desc->mode;
		desc->mode = UBI_EXCLUSIVE;
	}
	spin_unlock(&vol->ubi->volumes_lock);

	return err;
}

/**
 * revoke_exclusive - revoke exclusive mode.
 * @desc: volume descriptor
 * @mode: new mode to switch to
 */
static void revoke_exclusive(struct ubi_volume_desc *desc, int mode)
{
	struct ubi_volume *vol = desc->vol;

	spin_lock(&vol->ubi->volumes_lock);
	ubi_assert(vol->readers == 0 && vol->writers == 0);
	ubi_assert(vol->exclusive == 1 && desc->mode == UBI_EXCLUSIVE);
	vol->exclusive = 0;
	if (mode == UBI_READONLY)
		vol->readers = 1;
	else if (mode == UBI_READWRITE)
		vol->writers = 1;
	else
		vol->exclusive = 1;
	spin_unlock(&vol->ubi->volumes_lock);

	desc->mode = mode;
}

static int vol_cdev_open(struct inode *inode, struct file *file)
{
	struct ubi_volume_desc *desc;
	const struct ubi_device *ubi = major_to_device(imajor(inode));
	int vol_id = iminor(inode) - 1;
	int mode;

	if (file->f_mode & FMODE_WRITE)
		mode = UBI_READWRITE;
	else
		mode = UBI_READONLY;

	dbg_msg("open volume %d, mode %d", vol_id, mode);

	desc = ubi_open_volume(ubi->ubi_num, vol_id, mode);
	if (IS_ERR(desc))
		return PTR_ERR(desc);

	file->private_data = desc;
	return 0;
}

static int vol_cdev_release(struct inode *inode, struct file *file)
{
	struct ubi_volume_desc *desc = file->private_data;
	struct ubi_volume *vol = desc->vol;

	dbg_msg("release volume %d, mode %d", vol->vol_id, desc->mode);

	if (vol->updating) {
		ubi_warn("update of volume %d not finished, volume is damaged",
			 vol->vol_id);
		vol->updating = 0;
		vfree(vol->upd_buf);
	}

	ubi_close_volume(desc);
	return 0;
}

static loff_t vol_cdev_llseek(struct file *file, loff_t offset, int origin)
{
	struct ubi_volume_desc *desc = file->private_data;
	struct ubi_volume *vol = desc->vol;
	loff_t new_offset;

	if (vol->updating) {
		 /* Update is in progress, seeking is prohibited */
		dbg_err("updating");
		return -EBUSY;
	}

	switch (origin) {
	case 0: /* SEEK_SET */
		new_offset = offset;
		break;
	case 1: /* SEEK_CUR */
		new_offset = file->f_pos + offset;
		break;
	case 2: /* SEEK_END */
		new_offset = vol->used_bytes + offset;
		break;
	default:
		return -EINVAL;
	}

	if (new_offset < 0 || new_offset > vol->used_bytes) {
		dbg_err("bad seek %lld", new_offset);
		return -EINVAL;
	}

	dbg_msg("seek volume %d, offset %lld, origin %d, new offset %lld",
		vol->vol_id, offset, origin, new_offset);

	file->f_pos = new_offset;
	return new_offset;
}

static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
			     loff_t *offp)
{
	struct ubi_volume_desc *desc = file->private_data;
	struct ubi_volume *vol = desc->vol;
	struct ubi_device *ubi = vol->ubi;
	int err, lnum, off, len,  vol_id = desc->vol->vol_id, tbuf_size;
	size_t count_save = count;
	void *tbuf;
	uint64_t tmp;

	dbg_msg("read %zd bytes from offset %lld of volume %d",
		count, *offp, vol_id);

	if (vol->updating) {
		dbg_err("updating");
		return -EBUSY;
	}
	if (vol->upd_marker) {
		dbg_err("damaged volume, update marker is set");
		return -EBADF;
	}
	if (*offp == vol->used_bytes || count == 0)
		return 0;

	if (vol->corrupted)
		dbg_msg("read from corrupted volume %d", vol_id);

	if (*offp + count > vol->used_bytes)
		count_save = count = vol->used_bytes - *offp;

	tbuf_size = vol->usable_leb_size;
	if (count < tbuf_size)
		tbuf_size = ALIGN(count, ubi->min_io_size);
	tbuf = vmalloc(tbuf_size);
	if (!tbuf)
		return -ENOMEM;

	len = count > tbuf_size ? tbuf_size : count;

	tmp = *offp;
	off = do_div(tmp, vol->usable_leb_size);
	lnum = tmp;

	do {
		cond_resched();

		if (off + len >= vol->usable_leb_size)
			len = vol->usable_leb_size - off;

		err = ubi_eba_read_leb(ubi, vol, lnum, tbuf, off, len, 0);
		if (err)
			break;

		off += len;
		if (off == vol->usable_leb_size) {
			lnum += 1;
			off -= vol->usable_leb_size;
		}

		count -= len;
		*offp += len;

		err = copy_to_user(buf, tbuf, len);
		if (err) {
			err = -EFAULT;
			break;
		}

		buf += len;
		len = count > tbuf_size ? tbuf_size : count;
	} while (count);

	vfree(tbuf);
	return err ? err : count_save - count;
}

#ifdef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO

/*
 * This function allows to directly write to dynamic UBI volumes, without
 * issuing the volume update operation. Available only as a debugging feature.
 * Very useful for testing UBI.
 */
static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
				     size_t count, loff_t *offp)
{
	struct ubi_volume_desc *desc = file->private_data;
	struct ubi_volume *vol = desc->vol;
	struct ubi_device *ubi = vol->ubi;
	int lnum, off, len, tbuf_size, vol_id = vol->vol_id, err = 0;
	size_t count_save = count;
	char *tbuf;
	uint64_t tmp;

	dbg_msg("requested: write %zd bytes to offset %lld of volume %u",
		count, *offp, desc->vol->vol_id);

	if (vol->vol_type == UBI_STATIC_VOLUME)
		return -EROFS;

	tmp = *offp;
	off = do_div(tmp, vol->usable_leb_size);
	lnum = tmp;

	if (off % ubi->min_io_size) {
		dbg_err("unaligned position");
		return -EINVAL;
	}

	if (*offp + count > vol->used_bytes)
		count_save = count = vol->used_bytes - *offp;

	/* We can write only in fractions of the minimum I/O unit */
	if (count % ubi->min_io_size) {
		dbg_err("unaligned write length");
		return -EINVAL;
	}

	tbuf_size = vol->usable_leb_size;
	if (count < tbuf_size)
		tbuf_size = ALIGN(count, ubi->min_io_size);
	tbuf = vmalloc(tbuf_size);
	if (!tbuf)
		return -ENOMEM;

	len = count > tbuf_size ? tbuf_size : count;

	while (count) {
		cond_resched();

		if (off + len >= vol->usable_leb_size)
			len = vol->usable_leb_size - off;

		err = copy_from_user(tbuf, buf, len);
		if (err) {
			err = -EFAULT;
			break;
		}

		err = ubi_eba_write_leb(ubi, vol, lnum, tbuf, off, len,
					UBI_UNKNOWN);
		if (err)
			break;

		off += len;
		if (off == vol->usable_leb_size) {
			lnum += 1;
			off -= vol->usable_leb_size;
		}

		count -= len;
		*offp += len;
		buf += len;
		len = count > tbuf_size ? tbuf_size : count;
	}

	vfree(tbuf);
	return err ? err : count_save - count;
}

#else
#define vol_cdev_direct_write(file, buf, count, offp) -EPERM
#endif /* CONFIG_MTD_UBI_DEBUG_USERSPACE_IO */

static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
			      size_t count, loff_t *offp)
{
	int err = 0;
	struct ubi_volume_desc *desc = file->private_data;
	struct ubi_volume *vol = desc->vol;
	struct ubi_device *ubi = vol->ubi;

	if (!vol->updating)
		return vol_cdev_direct_write(file, buf, count, offp);

	err = ubi_more_update_data(ubi, vol->vol_id, buf, count);
	if (err < 0) {
		ubi_err("cannot write %zd bytes of update data, error %d",
			count, err);
		return err;
	}

	if (err) {
		/*
		 * Update is finished, @err contains number of actually written
		 * bytes now.
		 */
		count = err;

		err = ubi_check_volume(ubi, vol->vol_id);
		if (err < 0)
			return err;

		if (err) {
			ubi_warn("volume %d on UBI device %d is corrupted",
				 vol->vol_id, ubi->ubi_num);
			vol->corrupted = 1;
		}
		vol->checked = 1;
		ubi_gluebi_updated(vol);
		revoke_exclusive(desc, UBI_READWRITE);
	}

	*offp += count;
	return count;
}

static int vol_cdev_ioctl(struct inode *inode, struct file *file,
			  unsigned int cmd, unsigned long arg)
{
	int err = 0;
	struct ubi_volume_desc *desc = file->private_data;
	struct ubi_volume *vol = desc->vol;
	struct ubi_device *ubi = vol->ubi;
	void __user *argp = (void __user *)arg;

	switch (cmd) {
	/* Volume update command */
	case UBI_IOCVOLUP:
	{
		int64_t bytes, rsvd_bytes;

		if (!capable(CAP_SYS_RESOURCE)) {
			err = -EPERM;
			break;
		}

		err = copy_from_user(&bytes, argp, sizeof(int64_t));
		if (err) {
			err = -EFAULT;
			break;
		}

		if (desc->mode == UBI_READONLY) {
			err = -EROFS;
			break;
		}

		rsvd_bytes = vol->reserved_pebs * (ubi->leb_size-vol->data_pad);
		if (bytes < 0 || bytes > rsvd_bytes) {
			err = -EINVAL;
			break;
		}

		err = get_exclusive(desc);
		if (err < 0)
			break;

		err = ubi_start_update(ubi, vol->vol_id, bytes);
		if (bytes == 0)
			revoke_exclusive(desc, UBI_READWRITE);

		file->f_pos = 0;
		break;
	}

#ifdef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO
	/* Logical eraseblock erasure command */
	case UBI_IOCEBER:
	{
		int32_t lnum;

		err = get_user(lnum, (__user int32_t *)argp);
		if (err) {
			err = -EFAULT;
			break;
		}

		if (desc->mode == UBI_READONLY) {
			err = -EROFS;
			break;
		}

		if (lnum < 0 || lnum >= vol->reserved_pebs) {
			err = -EINVAL;
			break;
		}

		if (vol->vol_type != UBI_DYNAMIC_VOLUME) {
			err = -EROFS;
			break;
		}

		dbg_msg("erase LEB %d:%d", vol->vol_id, lnum);
		err = ubi_eba_unmap_leb(ubi, vol, lnum);
		if (err)
			break;

		err = ubi_wl_flush(ubi);
		break;
	}
#endif

	default:
		err = -ENOTTY;
		break;
	}

	return err;
}

/**
 * verify_mkvol_req - verify volume creation request.
 * @ubi: UBI device description object
 * @req: the request to check
 *
 * This function zero if the request is correct, and %-EINVAL if not.
 */
static int verify_mkvol_req(const struct ubi_device *ubi,
			    const struct ubi_mkvol_req *req)
{
	int n, err = -EINVAL;

	if (req->bytes < 0 || req->alignment < 0 || req->vol_type < 0 ||
	    req->name_len < 0)
		goto bad;

	if ((req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) &&
	    req->vol_id != UBI_VOL_NUM_AUTO)
		goto bad;

	if (req->alignment == 0)
		goto bad;

	if (req->bytes == 0)
		goto bad;

	if (req->vol_type != UBI_DYNAMIC_VOLUME &&
	    req->vol_type != UBI_STATIC_VOLUME)
		goto bad;

	if (req->alignment > ubi->leb_size)
		goto bad;

	n = req->alignment % ubi->min_io_size;
	if (req->alignment != 1 && n)
		goto bad;

	if (req->name_len > UBI_VOL_NAME_MAX) {
		err = -ENAMETOOLONG;
		goto bad;
	}

	return 0;

bad:
	dbg_err("bad volume creation request");
	ubi_dbg_dump_mkvol_req(req);
	return err;
}

/**
 * verify_rsvol_req - verify volume re-size request.
 * @ubi: UBI device description object
 * @req: the request to check
 *
 * This function returns zero if the request is correct, and %-EINVAL if not.
 */
static int verify_rsvol_req(const struct ubi_device *ubi,
			    const struct ubi_rsvol_req *req)
{
	if (req->bytes <= 0)
		return -EINVAL;

	if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots)
		return -EINVAL;

	return 0;
}

static int ubi_cdev_ioctl(struct inode *inode, struct file *file,
			  unsigned int cmd, unsigned long arg)
{
	int err = 0;
	struct ubi_device *ubi;
	struct ubi_volume_desc *desc;
	void __user *argp = (void __user *)arg;

	if (!capable(CAP_SYS_RESOURCE))
		return -EPERM;

	ubi = major_to_device(imajor(inode));
	if (IS_ERR(ubi))
		return PTR_ERR(ubi);

	switch (cmd) {
	/* Create volume command */
	case UBI_IOCMKVOL:
	{
		struct ubi_mkvol_req req;

		dbg_msg("create volume");
		err = copy_from_user(&req, argp,
				       sizeof(struct ubi_mkvol_req));
		if (err) {
			err = -EFAULT;
			break;
		}

		err = verify_mkvol_req(ubi, &req);
		if (err)
			break;

		req.name[req.name_len] = '\0';

		mutex_lock(&ubi->volumes_mutex);
		err = ubi_create_volume(ubi, &req);
		mutex_unlock(&ubi->volumes_mutex);
		if (err)
			break;

		err = put_user(req.vol_id, (__user int32_t *)argp);
		if (err)
			err = -EFAULT;

		break;
	}

	/* Remove volume command */
	case UBI_IOCRMVOL:
	{
		int vol_id;

		dbg_msg("remove volume");
		err = get_user(vol_id, (__user int32_t *)argp);
		if (err) {
			err = -EFAULT;
			break;
		}

		desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
		if (IS_ERR(desc)) {
			err = PTR_ERR(desc);
			break;
		}

		mutex_lock(&ubi->volumes_mutex);
		err = ubi_remove_volume(desc);
		mutex_unlock(&ubi->volumes_mutex);

		/*
		 * The volume is deleted (unless an error occurred), and the
		 * 'struct ubi_volume' object will be freed when
		 * 'ubi_close_volume()' will call 'put_device()'.
		 */
		ubi_close_volume(desc);
		break;
	}

	/* Re-size volume command */
	case UBI_IOCRSVOL:
	{
		int pebs;
		uint64_t tmp;
		struct ubi_rsvol_req req;

		dbg_msg("re-size volume");
		err = copy_from_user(&req, argp,
				       sizeof(struct ubi_rsvol_req));
		if (err) {
			err = -EFAULT;
			break;
		}

		err = verify_rsvol_req(ubi, &req);
		if (err)
			break;

		desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
		if (IS_ERR(desc)) {
			err = PTR_ERR(desc);
			break;
		}

		tmp = req.bytes;
		pebs = !!do_div(tmp, desc->vol->usable_leb_size);
		pebs += tmp;

		mutex_lock(&ubi->volumes_mutex);
		err = ubi_resize_volume(desc, pebs);
		mutex_unlock(&ubi->volumes_mutex);
		ubi_close_volume(desc);
		break;
	}

	default:
		err = -ENOTTY;
		break;
	}

	return err;
}

/* UBI character device operations */
struct file_operations ubi_cdev_operations = {
	.owner = THIS_MODULE,
	.ioctl = ubi_cdev_ioctl,
	.llseek = no_llseek,
};

/* UBI volume character device operations */
struct file_operations ubi_vol_cdev_operations = {
	.owner   = THIS_MODULE,
	.open    = vol_cdev_open,
	.release = vol_cdev_release,
	.llseek  = vol_cdev_llseek,
	.read    = vol_cdev_read,
	.write   = vol_cdev_write,
	.ioctl   = vol_cdev_ioctl,
};