drivers/mtd/ubi/cdev.c

   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  */
  59 static 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         return NULL;
  68 }
  69
  70 /**
  71  * get_exclusive - get exclusive access to an UBI volume.
  72  * @desc: volume descriptor
  73  *
  74  * This function changes UBI volume open mode to "exclusive". Returns previous
  75  * mode value (positive integer) in case of success and a negative error code
  76  * in case of failure.
  77  */
  78 static int get_exclusive(struct ubi_volume_desc *desc)
  79 {
  80         int users, err;
  81         struct ubi_volume *vol = desc->vol;
  82
  83         spin_lock(&vol->ubi->volumes_lock);
  84         users = vol->readers + vol->writers + vol->exclusive;
  85         ubi_assert(users > 0);
  86         if (users > 1) {
  87                 dbg_err("%d users for volume %d", users, vol->vol_id);
  88                 err = -EBUSY;
  89         } else {
  90                 vol->readers = vol->writers = 0;
  91                 vol->exclusive = 1;
  92                 err = desc->mode;
  93                 desc->mode = UBI_EXCLUSIVE;
  94         }
  95         spin_unlock(&vol->ubi->volumes_lock);
  96
  97         return err;
  98 }
  99
 100 /**
 101  * revoke_exclusive - revoke exclusive mode.
 102  * @desc: volume descriptor
 103  * @mode: new mode to switch to
 104  */
 105 static void revoke_exclusive(struct ubi_volume_desc *desc, int mode)
 106 {
 107         struct ubi_volume *vol = desc->vol;
 108
 109         spin_lock(&vol->ubi->volumes_lock);
 110         ubi_assert(vol->readers == 0 && vol->writers == 0);
 111         ubi_assert(vol->exclusive == 1 && desc->mode == UBI_EXCLUSIVE);
 112         vol->exclusive = 0;
 113         if (mode == UBI_READONLY)
 114                 vol->readers = 1;
 115         else if (mode == UBI_READWRITE)
 116                 vol->writers = 1;
 117         else
 118                 vol->exclusive = 1;
 119         spin_unlock(&vol->ubi->volumes_lock);
 120
 121         desc->mode = mode;
 122 }
 123
 124 static int vol_cdev_open(struct inode *inode, struct file *file)
 125 {
 126         struct ubi_volume_desc *desc;
 127         const struct ubi_device *ubi = major_to_device(imajor(inode));
 128         int vol_id = iminor(inode) - 1;
 129         int mode;
 130
 131         if (file->f_mode & FMODE_WRITE)
 132                 mode = UBI_READWRITE;
 133         else
 134                 mode = UBI_READONLY;
 135
 136         dbg_msg("open volume %d, mode %d", vol_id, mode);
 137
 138         desc = ubi_open_volume(ubi->ubi_num, vol_id, mode);
 139         if (IS_ERR(desc))
 140                 return PTR_ERR(desc);
 141
 142         file->private_data = desc;
 143         return 0;
 144 }
 145
 146 static int vol_cdev_release(struct inode *inode, struct file *file)
 147 {
 148         struct ubi_volume_desc *desc = file->private_data;
 149         struct ubi_volume *vol = desc->vol;
 150
 151         dbg_msg("release volume %d, mode %d", vol->vol_id, desc->mode);
 152
 153         if (vol->updating) {
 154                 ubi_warn("update of volume %d not finished, volume is damaged",
 155                          vol->vol_id);
 156                 vol->updating = 0;
 157                 vfree(vol->upd_buf);
 158         }
 159
 160         ubi_close_volume(desc);
 161         return 0;
 162 }
 163
 164 static loff_t vol_cdev_llseek(struct file *file, loff_t offset, int origin)
 165 {
 166         struct ubi_volume_desc *desc = file->private_data;
 167         struct ubi_volume *vol = desc->vol;
 168         loff_t new_offset;
 169
 170         if (vol->updating) {
 171                  /* Update is in progress, seeking is prohibited */
 172                 dbg_err("updating");
 173                 return -EBUSY;
 174         }
 175
 176         switch (origin) {
 177         case 0: /* SEEK_SET */
 178                 new_offset = offset;
 179                 break;
 180         case 1: /* SEEK_CUR */
 181                 new_offset = file->f_pos + offset;
 182                 break;
 183         case 2: /* SEEK_END */
 184                 new_offset = vol->used_bytes + offset;
 185                 break;
 186         default:
 187                 return -EINVAL;
 188         }
 189
 190         if (new_offset < 0 || new_offset > vol->used_bytes) {
 191                 dbg_err("bad seek %lld", new_offset);
 192                 return -EINVAL;
 193         }
 194
 195         dbg_msg("seek volume %d, offset %lld, origin %d, new offset %lld",
 196                 vol->vol_id, offset, origin, new_offset);
 197
 198         file->f_pos = new_offset;
 199         return new_offset;
 200 }
 201
 202 static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
 203                              loff_t *offp)
 204 {
 205         struct ubi_volume_desc *desc = file->private_data;
 206         struct ubi_volume *vol = desc->vol;
 207         struct ubi_device *ubi = vol->ubi;
 208         int err, lnum, off, len,  vol_id = desc->vol->vol_id, tbuf_size;
 209         size_t count_save = count;
 210         void *tbuf;
 211         uint64_t tmp;
 212
 213         dbg_msg("read %zd bytes from offset %lld of volume %d",
 214                 count, *offp, vol_id);
 215
 216         if (vol->updating) {
 217                 dbg_err("updating");
 218                 return -EBUSY;
 219         }
 220         if (vol->upd_marker) {
 221                 dbg_err("damaged volume, update marker is set");
 222                 return -EBADF;
 223         }
 224         if (*offp == vol->used_bytes || count == 0)
 225                 return 0;
 226
 227         if (vol->corrupted)
 228                 dbg_msg("read from corrupted volume %d", vol_id);
 229
 230         if (*offp + count > vol->used_bytes)
 231                 count_save = count = vol->used_bytes - *offp;
 232
 233         tbuf_size = vol->usable_leb_size;
 234         if (count < tbuf_size)
 235                 tbuf_size = ALIGN(count, ubi->min_io_size);
 236         tbuf = vmalloc(tbuf_size);
 237         if (!tbuf)
 238                 return -ENOMEM;
 239
 240         len = count > tbuf_size ? tbuf_size : count;
 241
 242         tmp = *offp;
 243         off = do_div(tmp, vol->usable_leb_size);
 244         lnum = tmp;
 245
 246         do {
 247                 cond_resched();
 248
 249                 if (off + len >= vol->usable_leb_size)
 250                         len = vol->usable_leb_size - off;
 251
 252                 err = ubi_eba_read_leb(ubi, vol_id, lnum, tbuf, off, len, 0);
 253                 if (err)
 254                         break;
 255
 256                 off += len;
 257                 if (off == vol->usable_leb_size) {
 258                         lnum += 1;
 259                         off -= vol->usable_leb_size;
 260                 }
 261
 262                 count -= len;
 263                 *offp += len;
 264
 265                 err = copy_to_user(buf, tbuf, len);
 266                 if (err) {
 267                         err = -EFAULT;
 268                         break;
 269                 }
 270
 271                 buf += len;
 272                 len = count > tbuf_size ? tbuf_size : count;
 273         } while (count);
 274
 275         vfree(tbuf);
 276         return err ? err : count_save - count;
 277 }
 278
 279 #ifdef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO
 280
 281 /*
 282  * This function allows to directly write to dynamic UBI volumes, without
 283  * issuing the volume update operation. Available only as a debugging feature.
 284  * Very useful for testing UBI.
 285  */
 286 static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
 287                                      size_t count, loff_t *offp)
 288 {
 289         struct ubi_volume_desc *desc = file->private_data;
 290         struct ubi_volume *vol = desc->vol;
 291         struct ubi_device *ubi = vol->ubi;
 292         int lnum, off, len, tbuf_size, vol_id = vol->vol_id, err = 0;
 293         size_t count_save = count;
 294         char *tbuf;
 295         uint64_t tmp;
 296
 297         dbg_msg("requested: write %zd bytes to offset %lld of volume %u",
 298                 count, *offp, desc->vol->vol_id);
 299
 300         if (vol->vol_type == UBI_STATIC_VOLUME)
 301                 return -EROFS;
 302
 303         tmp = *offp;
 304         off = do_div(tmp, vol->usable_leb_size);
 305         lnum = tmp;
 306
 307         if (off % ubi->min_io_size) {
 308                 dbg_err("unaligned position");
 309                 return -EINVAL;
 310         }
 311
 312         if (*offp + count > vol->used_bytes)
 313                 count_save = count = vol->used_bytes - *offp;
 314
 315         /* We can write only in fractions of the minimum I/O unit */
 316         if (count % ubi->min_io_size) {
 317                 dbg_err("unaligned write length");
 318                 return -EINVAL;
 319         }
 320
 321         tbuf_size = vol->usable_leb_size;
 322         if (count < tbuf_size)
 323                 tbuf_size = ALIGN(count, ubi->min_io_size);
 324         tbuf = vmalloc(tbuf_size);
 325         if (!tbuf)
 326                 return -ENOMEM;
 327
 328         len = count > tbuf_size ? tbuf_size : count;
 329
 330         while (count) {
 331                 cond_resched();
 332
 333                 if (off + len >= vol->usable_leb_size)
 334                         len = vol->usable_leb_size - off;
 335
 336                 err = copy_from_user(tbuf, buf, len);
 337                 if (err) {
 338                         err = -EFAULT;
 339                         break;
 340                 }
 341
 342                 err = ubi_eba_write_leb(ubi, vol_id, lnum, tbuf, off, len,
 343                                         UBI_UNKNOWN);
 344                 if (err)
 345                         break;
 346
 347                 off += len;
 348                 if (off == vol->usable_leb_size) {
 349                         lnum += 1;
 350                         off -= vol->usable_leb_size;
 351                 }
 352
 353                 count -= len;
 354                 *offp += len;
 355                 buf += len;
 356                 len = count > tbuf_size ? tbuf_size : count;
 357         }
 358
 359         vfree(tbuf);
 360         return err ? err : count_save - count;
 361 }
 362
 363 #else
 364 #define vol_cdev_direct_write(file, buf, count, offp) -EPERM
 365 #endif /* CONFIG_MTD_UBI_DEBUG_USERSPACE_IO */
 366
 367 static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
 368                               size_t count, loff_t *offp)
 369 {
 370         int err = 0;
 371         struct ubi_volume_desc *desc = file->private_data;
 372         struct ubi_volume *vol = desc->vol;
 373         struct ubi_device *ubi = vol->ubi;
 374
 375         if (!vol->updating)
 376                 return vol_cdev_direct_write(file, buf, count, offp);
 377
 378         err = ubi_more_update_data(ubi, vol->vol_id, buf, count);
 379         if (err < 0) {
 380                 ubi_err("cannot write %zd bytes of update data", count);
 381                 return err;
 382         }
 383
 384         if (err) {
 385                 /*
 386                  * Update is finished, @err contains number of actually written
 387                  * bytes now.
 388                  */
 389                 count = err;
 390
 391                 err = ubi_check_volume(ubi, vol->vol_id);
 392                 if (err < 0)
 393                         return err;
 394
 395                 if (err) {
 396                         ubi_warn("volume %d on UBI device %d is corrupted",
 397                                  vol->vol_id, ubi->ubi_num);
 398                         vol->corrupted = 1;
 399                 }
 400                 vol->checked = 1;
 401                 ubi_gluebi_updated(vol);
 402                 revoke_exclusive(desc, UBI_READWRITE);
 403         }
 404
 405         *offp += count;
 406         return count;
 407 }
 408
 409 static int vol_cdev_ioctl(struct inode *inode, struct file *file,
 410                           unsigned int cmd, unsigned long arg)
 411 {
 412         int err = 0;
 413         struct ubi_volume_desc *desc = file->private_data;
 414         struct ubi_volume *vol = desc->vol;
 415         struct ubi_device *ubi = vol->ubi;
 416         void __user *argp = (void __user *)arg;
 417
 418         switch (cmd) {
 419         /* Volume update command */
 420         case UBI_IOCVOLUP:
 421         {
 422                 int64_t bytes, rsvd_bytes;
 423
 424                 if (!capable(CAP_SYS_RESOURCE)) {
 425                         err = -EPERM;
 426                         break;
 427                 }
 428
 429                 err = copy_from_user(&bytes, argp, sizeof(int64_t));
 430                 if (err) {
 431                         err = -EFAULT;
 432                         break;
 433                 }
 434
 435                 if (desc->mode == UBI_READONLY) {
 436                         err = -EROFS;
 437                         break;
 438                 }
 439
 440                 rsvd_bytes = vol->reserved_pebs * (ubi->leb_size-vol->data_pad);
 441                 if (bytes < 0 || bytes > rsvd_bytes) {
 442                         err = -EINVAL;
 443                         break;
 444                 }
 445
 446                 err = get_exclusive(desc);
 447                 if (err < 0)
 448                         break;
 449
 450                 err = ubi_start_update(ubi, vol->vol_id, bytes);
 451                 if (bytes == 0)
 452                         revoke_exclusive(desc, UBI_READWRITE);
 453
 454                 file->f_pos = 0;
 455                 break;
 456         }
 457
 458 #ifdef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO
 459         /* Logical eraseblock erasure command */
 460         case UBI_IOCEBER:
 461         {
 462                 int32_t lnum;
 463
 464                 err = get_user(lnum, (__user int32_t *)argp);
 465                 if (err) {
 466                         err = -EFAULT;
 467                         break;
 468                 }
 469
 470                 if (desc->mode == UBI_READONLY) {
 471                         err = -EROFS;
 472                         break;
 473                 }
 474
 475                 if (lnum < 0 || lnum >= vol->reserved_pebs) {
 476                         err = -EINVAL;
 477                         break;
 478                 }
 479
 480                 if (vol->vol_type != UBI_DYNAMIC_VOLUME) {
 481                         err = -EROFS;
 482                         break;
 483                 }
 484
 485                 dbg_msg("erase LEB %d:%d", vol->vol_id, lnum);
 486                 err = ubi_eba_unmap_leb(ubi, vol->vol_id, lnum);
 487                 if (err)
 488                         break;
 489
 490                 err = ubi_wl_flush(ubi);
 491                 break;
 492         }
 493 #endif
 494
 495         default:
 496                 err = -ENOTTY;
 497                 break;
 498         }
 499
 500         return err;
 501 }
 502
 503 /**
 504  * verify_mkvol_req - verify volume creation request.
 505  * @ubi: UBI device description object
 506  * @req: the request to check
 507  *
 508  * This function zero if the request is correct, and %-EINVAL if not.
 509  */
 510 static int verify_mkvol_req(const struct ubi_device *ubi,
 511                             const struct ubi_mkvol_req *req)
 512 {
 513         int n, err = -EINVAL;
 514
 515         if (req->bytes < 0 || req->alignment < 0 || req->vol_type < 0 ||
 516             req->name_len < 0)
 517                 goto bad;
 518
 519         if ((req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) &&
 520             req->vol_id != UBI_VOL_NUM_AUTO)
 521                 goto bad;
 522
 523         if (req->alignment == 0)
 524                 goto bad;
 525
 526         if (req->bytes == 0)
 527                 goto bad;
 528
 529         if (req->vol_type != UBI_DYNAMIC_VOLUME &&
 530             req->vol_type != UBI_STATIC_VOLUME)
 531                 goto bad;
 532
 533         if (req->alignment > ubi->leb_size)
 534                 goto bad;
 535
 536         n = req->alignment % ubi->min_io_size;
 537         if (req->alignment != 1 && n)
 538                 goto bad;
 539
 540         if (req->name_len > UBI_VOL_NAME_MAX) {
 541                 err = -ENAMETOOLONG;
 542                 goto bad;
 543         }
 544
 545         return 0;
 546
 547 bad:
 548         dbg_err("bad volume creation request");
 549         ubi_dbg_dump_mkvol_req(req);
 550         return err;
 551 }
 552
 553 /**
 554  * verify_rsvol_req - verify volume re-size request.
 555  * @ubi: UBI device description object
 556  * @req: the request to check
 557  *
 558  * This function returns zero if the request is correct, and %-EINVAL if not.
 559  */
 560 static int verify_rsvol_req(const struct ubi_device *ubi,
 561                             const struct ubi_rsvol_req *req)
 562 {
 563         if (req->bytes <= 0)
 564                 return -EINVAL;
 565
 566         if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots)
 567                 return -EINVAL;
 568
 569         return 0;
 570 }
 571
 572 static int ubi_cdev_ioctl(struct inode *inode, struct file *file,
 573                           unsigned int cmd, unsigned long arg)
 574 {
 575         int err = 0;
 576         struct ubi_device *ubi;
 577         struct ubi_volume_desc *desc;
 578         void __user *argp = (void __user *)arg;
 579
 580         if (!capable(CAP_SYS_RESOURCE))
 581                 return -EPERM;
 582
 583         ubi = major_to_device(imajor(inode));
 584         if (IS_ERR(ubi))
 585                 return PTR_ERR(ubi);
 586
 587         switch (cmd) {
 588         /* Create volume command */
 589         case UBI_IOCMKVOL:
 590         {
 591                 struct ubi_mkvol_req req;
 592
 593                 dbg_msg("create volume");
 594                 err = copy_from_user(&req, argp,
 595                                        sizeof(struct ubi_mkvol_req));
 596                 if (err) {
 597                         err = -EFAULT;
 598                         break;
 599                 }
 600
 601                 err = verify_mkvol_req(ubi, &req);
 602                 if (err)
 603                         break;
 604
 605                 req.name[req.name_len] = '\0';
 606
 607                 err = ubi_create_volume(ubi, &req);
 608                 if (err)
 609                         break;
 610
 611                 err = put_user(req.vol_id, (__user int32_t *)argp);
 612                 if (err)
 613                         err = -EFAULT;
 614
 615                 break;
 616         }
 617
 618         /* Remove volume command */
 619         case UBI_IOCRMVOL:
 620         {
 621                 int vol_id;
 622
 623                 dbg_msg("remove volume");
 624                 err = get_user(vol_id, (__user int32_t *)argp);
 625                 if (err) {
 626                         err = -EFAULT;
 627                         break;
 628                 }
 629
 630                 desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
 631                 if (IS_ERR(desc)) {
 632                         err = PTR_ERR(desc);
 633                         break;
 634                 }
 635
 636                 err = ubi_remove_volume(desc);
 637                 if (err)
 638                         ubi_close_volume(desc);
 639
 640                 break;
 641         }
 642
 643         /* Re-size volume command */
 644         case UBI_IOCRSVOL:
 645         {
 646                 int pebs;
 647                 uint64_t tmp;
 648                 struct ubi_rsvol_req req;
 649
 650                 dbg_msg("re-size volume");
 651                 err = copy_from_user(&req, argp,
 652                                        sizeof(struct ubi_rsvol_req));
 653                 if (err) {
 654                         err = -EFAULT;
 655                         break;
 656                 }
 657
 658                 err = verify_rsvol_req(ubi, &req);
 659                 if (err)
 660                         break;
 661
 662                 desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
 663                 if (IS_ERR(desc)) {
 664                         err = PTR_ERR(desc);
 665                         break;
 666                 }
 667
 668                 tmp = req.bytes;
 669                 pebs = !!do_div(tmp, desc->vol->usable_leb_size);
 670                 pebs += tmp;
 671
 672                 err = ubi_resize_volume(desc, pebs);
 673                 ubi_close_volume(desc);
 674                 break;
 675         }
 676
 677         default:
 678                 err = -ENOTTY;
 679                 break;
 680         }
 681
 682         return err;
 683 }
 684
 685 /* UBI character device operations */
 686 struct file_operations ubi_cdev_operations = {
 687         .owner = THIS_MODULE,
 688         .ioctl = ubi_cdev_ioctl,
 689         .llseek = no_llseek,
 690 };
 691
 692 /* UBI volume character device operations */
 693 struct file_operations ubi_vol_cdev_operations = {
 694         .owner   = THIS_MODULE,
 695         .open    = vol_cdev_open,
 696         .release = vol_cdev_release,
 697         .llseek  = vol_cdev_llseek,
 698         .read    = vol_cdev_read,
 699         .write   = vol_cdev_write,
 700         .ioctl   = vol_cdev_ioctl,
 701 };