linux/fs/autofs4/dev-ioctl.c
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   1/*
   2 * Copyright 2008 Red Hat, Inc. All rights reserved.
   3 * Copyright 2008 Ian Kent <raven@themaw.net>
   4 *
   5 * This file is part of the Linux kernel and is made available under
   6 * the terms of the GNU General Public License, version 2, or at your
   7 * option, any later version, incorporated herein by reference.
   8 */
   9
  10#include <linux/module.h>
  11#include <linux/vmalloc.h>
  12#include <linux/miscdevice.h>
  13#include <linux/init.h>
  14#include <linux/wait.h>
  15#include <linux/namei.h>
  16#include <linux/fcntl.h>
  17#include <linux/file.h>
  18#include <linux/fdtable.h>
  19#include <linux/sched.h>
  20#include <linux/compat.h>
  21#include <linux/syscalls.h>
  22#include <linux/magic.h>
  23#include <linux/dcache.h>
  24#include <linux/uaccess.h>
  25#include <linux/slab.h>
  26
  27#include "autofs_i.h"
  28
  29/*
  30 * This module implements an interface for routing autofs ioctl control
  31 * commands via a miscellaneous device file.
  32 *
  33 * The alternate interface is needed because we need to be able open
  34 * an ioctl file descriptor on an autofs mount that may be covered by
  35 * another mount. This situation arises when starting automount(8)
  36 * or other user space daemon which uses direct mounts or offset
  37 * mounts (used for autofs lazy mount/umount of nested mount trees),
  38 * which have been left busy at at service shutdown.
  39 */
  40
  41#define AUTOFS_DEV_IOCTL_SIZE   sizeof(struct autofs_dev_ioctl)
  42
  43typedef int (*ioctl_fn)(struct file *, struct autofs_sb_info *,
  44                        struct autofs_dev_ioctl *);
  45
  46static int check_name(const char *name)
  47{
  48        if (!strchr(name, '/'))
  49                return -EINVAL;
  50        return 0;
  51}
  52
  53/*
  54 * Check a string doesn't overrun the chunk of
  55 * memory we copied from user land.
  56 */
  57static int invalid_str(char *str, size_t size)
  58{
  59        if (memchr(str, 0, size))
  60                return 0;
  61        return -EINVAL;
  62}
  63
  64/*
  65 * Check that the user compiled against correct version of autofs
  66 * misc device code.
  67 *
  68 * As well as checking the version compatibility this always copies
  69 * the kernel interface version out.
  70 */
  71static int check_dev_ioctl_version(int cmd, struct autofs_dev_ioctl *param)
  72{
  73        int err = 0;
  74
  75        if ((AUTOFS_DEV_IOCTL_VERSION_MAJOR != param->ver_major) ||
  76            (AUTOFS_DEV_IOCTL_VERSION_MINOR < param->ver_minor)) {
  77                AUTOFS_WARN("ioctl control interface version mismatch: "
  78                     "kernel(%u.%u), user(%u.%u), cmd(%d)",
  79                     AUTOFS_DEV_IOCTL_VERSION_MAJOR,
  80                     AUTOFS_DEV_IOCTL_VERSION_MINOR,
  81                     param->ver_major, param->ver_minor, cmd);
  82                err = -EINVAL;
  83        }
  84
  85        /* Fill in the kernel version. */
  86        param->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR;
  87        param->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR;
  88
  89        return err;
  90}
  91
  92/*
  93 * Copy parameter control struct, including a possible path allocated
  94 * at the end of the struct.
  95 */
  96static struct autofs_dev_ioctl *copy_dev_ioctl(struct autofs_dev_ioctl __user *in)
  97{
  98        struct autofs_dev_ioctl tmp;
  99
 100        if (copy_from_user(&tmp, in, sizeof(tmp)))
 101                return ERR_PTR(-EFAULT);
 102
 103        if (tmp.size < sizeof(tmp))
 104                return ERR_PTR(-EINVAL);
 105
 106        return memdup_user(in, tmp.size);
 107}
 108
 109static inline void free_dev_ioctl(struct autofs_dev_ioctl *param)
 110{
 111        kfree(param);
 112        return;
 113}
 114
 115/*
 116 * Check sanity of parameter control fields and if a path is present
 117 * check that it is terminated and contains at least one "/".
 118 */
 119static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param)
 120{
 121        int err;
 122
 123        err = check_dev_ioctl_version(cmd, param);
 124        if (err) {
 125                AUTOFS_WARN("invalid device control module version "
 126                     "supplied for cmd(0x%08x)", cmd);
 127                goto out;
 128        }
 129
 130        if (param->size > sizeof(*param)) {
 131                err = invalid_str(param->path, param->size - sizeof(*param));
 132                if (err) {
 133                        AUTOFS_WARN(
 134                          "path string terminator missing for cmd(0x%08x)",
 135                          cmd);
 136                        goto out;
 137                }
 138
 139                err = check_name(param->path);
 140                if (err) {
 141                        AUTOFS_WARN("invalid path supplied for cmd(0x%08x)",
 142                                    cmd);
 143                        goto out;
 144                }
 145        }
 146
 147        err = 0;
 148out:
 149        return err;
 150}
 151
 152/*
 153 * Get the autofs super block info struct from the file opened on
 154 * the autofs mount point.
 155 */
 156static struct autofs_sb_info *autofs_dev_ioctl_sbi(struct file *f)
 157{
 158        struct autofs_sb_info *sbi = NULL;
 159        struct inode *inode;
 160
 161        if (f) {
 162                inode = f->f_path.dentry->d_inode;
 163                sbi = autofs4_sbi(inode->i_sb);
 164        }
 165        return sbi;
 166}
 167
 168/* Return autofs module protocol version */
 169static int autofs_dev_ioctl_protover(struct file *fp,
 170                                     struct autofs_sb_info *sbi,
 171                                     struct autofs_dev_ioctl *param)
 172{
 173        param->protover.version = sbi->version;
 174        return 0;
 175}
 176
 177/* Return autofs module protocol sub version */
 178static int autofs_dev_ioctl_protosubver(struct file *fp,
 179                                        struct autofs_sb_info *sbi,
 180                                        struct autofs_dev_ioctl *param)
 181{
 182        param->protosubver.sub_version = sbi->sub_version;
 183        return 0;
 184}
 185
 186static int find_autofs_mount(const char *pathname,
 187                             struct path *res,
 188                             int test(struct path *path, void *data),
 189                             void *data)
 190{
 191        struct path path;
 192        int err = kern_path(pathname, 0, &path);
 193        if (err)
 194                return err;
 195        err = -ENOENT;
 196        while (path.dentry == path.mnt->mnt_root) {
 197                if (path.dentry->d_sb->s_magic == AUTOFS_SUPER_MAGIC) {
 198                        if (test(&path, data)) {
 199                                path_get(&path);
 200                                if (!err) /* already found some */
 201                                        path_put(res);
 202                                *res = path;
 203                                err = 0;
 204                        }
 205                }
 206                if (!follow_up(&path))
 207                        break;
 208        }
 209        path_put(&path);
 210        return err;
 211}
 212
 213static int test_by_dev(struct path *path, void *p)
 214{
 215        return path->dentry->d_sb->s_dev == *(dev_t *)p;
 216}
 217
 218static int test_by_type(struct path *path, void *p)
 219{
 220        struct autofs_info *ino = autofs4_dentry_ino(path->dentry);
 221        return ino && ino->sbi->type & *(unsigned *)p;
 222}
 223
 224/*
 225 * Open a file descriptor on the autofs mount point corresponding
 226 * to the given path and device number (aka. new_encode_dev(sb->s_dev)).
 227 */
 228static int autofs_dev_ioctl_open_mountpoint(const char *name, dev_t devid)
 229{
 230        int err, fd;
 231
 232        fd = get_unused_fd_flags(O_CLOEXEC);
 233        if (likely(fd >= 0)) {
 234                struct file *filp;
 235                struct path path;
 236
 237                err = find_autofs_mount(name, &path, test_by_dev, &devid);
 238                if (err)
 239                        goto out;
 240
 241                /*
 242                 * Find autofs super block that has the device number
 243                 * corresponding to the autofs fs we want to open.
 244                 */
 245
 246                filp = dentry_open(&path, O_RDONLY, current_cred());
 247                path_put(&path);
 248                if (IS_ERR(filp)) {
 249                        err = PTR_ERR(filp);
 250                        goto out;
 251                }
 252
 253                fd_install(fd, filp);
 254        }
 255
 256        return fd;
 257
 258out:
 259        put_unused_fd(fd);
 260        return err;
 261}
 262
 263/* Open a file descriptor on an autofs mount point */
 264static int autofs_dev_ioctl_openmount(struct file *fp,
 265                                      struct autofs_sb_info *sbi,
 266                                      struct autofs_dev_ioctl *param)
 267{
 268        const char *path;
 269        dev_t devid;
 270        int err, fd;
 271
 272        /* param->path has already been checked */
 273        if (!param->openmount.devid)
 274                return -EINVAL;
 275
 276        param->ioctlfd = -1;
 277
 278        path = param->path;
 279        devid = new_decode_dev(param->openmount.devid);
 280
 281        err = 0;
 282        fd = autofs_dev_ioctl_open_mountpoint(path, devid);
 283        if (unlikely(fd < 0)) {
 284                err = fd;
 285                goto out;
 286        }
 287
 288        param->ioctlfd = fd;
 289out:
 290        return err;
 291}
 292
 293/* Close file descriptor allocated above (user can also use close(2)). */
 294static int autofs_dev_ioctl_closemount(struct file *fp,
 295                                       struct autofs_sb_info *sbi,
 296                                       struct autofs_dev_ioctl *param)
 297{
 298        return sys_close(param->ioctlfd);
 299}
 300
 301/*
 302 * Send "ready" status for an existing wait (either a mount or an expire
 303 * request).
 304 */
 305static int autofs_dev_ioctl_ready(struct file *fp,
 306                                  struct autofs_sb_info *sbi,
 307                                  struct autofs_dev_ioctl *param)
 308{
 309        autofs_wqt_t token;
 310
 311        token = (autofs_wqt_t) param->ready.token;
 312        return autofs4_wait_release(sbi, token, 0);
 313}
 314
 315/*
 316 * Send "fail" status for an existing wait (either a mount or an expire
 317 * request).
 318 */
 319static int autofs_dev_ioctl_fail(struct file *fp,
 320                                 struct autofs_sb_info *sbi,
 321                                 struct autofs_dev_ioctl *param)
 322{
 323        autofs_wqt_t token;
 324        int status;
 325
 326        token = (autofs_wqt_t) param->fail.token;
 327        status = param->fail.status ? param->fail.status : -ENOENT;
 328        return autofs4_wait_release(sbi, token, status);
 329}
 330
 331/*
 332 * Set the pipe fd for kernel communication to the daemon.
 333 *
 334 * Normally this is set at mount using an option but if we
 335 * are reconnecting to a busy mount then we need to use this
 336 * to tell the autofs mount about the new kernel pipe fd. In
 337 * order to protect mounts against incorrectly setting the
 338 * pipefd we also require that the autofs mount be catatonic.
 339 *
 340 * This also sets the process group id used to identify the
 341 * controlling process (eg. the owning automount(8) daemon).
 342 */
 343static int autofs_dev_ioctl_setpipefd(struct file *fp,
 344                                      struct autofs_sb_info *sbi,
 345                                      struct autofs_dev_ioctl *param)
 346{
 347        int pipefd;
 348        int err = 0;
 349
 350        if (param->setpipefd.pipefd == -1)
 351                return -EINVAL;
 352
 353        pipefd = param->setpipefd.pipefd;
 354
 355        mutex_lock(&sbi->wq_mutex);
 356        if (!sbi->catatonic) {
 357                mutex_unlock(&sbi->wq_mutex);
 358                return -EBUSY;
 359        } else {
 360                struct file *pipe = fget(pipefd);
 361                if (!pipe) {
 362                        err = -EBADF;
 363                        goto out;
 364                }
 365                if (autofs_prepare_pipe(pipe) < 0) {
 366                        err = -EPIPE;
 367                        fput(pipe);
 368                        goto out;
 369                }
 370                sbi->oz_pgrp = task_pgrp_nr(current);
 371                sbi->pipefd = pipefd;
 372                sbi->pipe = pipe;
 373                sbi->catatonic = 0;
 374        }
 375out:
 376        mutex_unlock(&sbi->wq_mutex);
 377        return err;
 378}
 379
 380/*
 381 * Make the autofs mount point catatonic, no longer responsive to
 382 * mount requests. Also closes the kernel pipe file descriptor.
 383 */
 384static int autofs_dev_ioctl_catatonic(struct file *fp,
 385                                      struct autofs_sb_info *sbi,
 386                                      struct autofs_dev_ioctl *param)
 387{
 388        autofs4_catatonic_mode(sbi);
 389        return 0;
 390}
 391
 392/* Set the autofs mount timeout */
 393static int autofs_dev_ioctl_timeout(struct file *fp,
 394                                    struct autofs_sb_info *sbi,
 395                                    struct autofs_dev_ioctl *param)
 396{
 397        unsigned long timeout;
 398
 399        timeout = param->timeout.timeout;
 400        param->timeout.timeout = sbi->exp_timeout / HZ;
 401        sbi->exp_timeout = timeout * HZ;
 402        return 0;
 403}
 404
 405/*
 406 * Return the uid and gid of the last request for the mount
 407 *
 408 * When reconstructing an autofs mount tree with active mounts
 409 * we need to re-connect to mounts that may have used the original
 410 * process uid and gid (or string variations of them) for mount
 411 * lookups within the map entry.
 412 */
 413static int autofs_dev_ioctl_requester(struct file *fp,
 414                                      struct autofs_sb_info *sbi,
 415                                      struct autofs_dev_ioctl *param)
 416{
 417        struct autofs_info *ino;
 418        struct path path;
 419        dev_t devid;
 420        int err = -ENOENT;
 421
 422        if (param->size <= sizeof(*param)) {
 423                err = -EINVAL;
 424                goto out;
 425        }
 426
 427        devid = sbi->sb->s_dev;
 428
 429        param->requester.uid = param->requester.gid = -1;
 430
 431        err = find_autofs_mount(param->path, &path, test_by_dev, &devid);
 432        if (err)
 433                goto out;
 434
 435        ino = autofs4_dentry_ino(path.dentry);
 436        if (ino) {
 437                err = 0;
 438                autofs4_expire_wait(path.dentry);
 439                spin_lock(&sbi->fs_lock);
 440                param->requester.uid = ino->uid;
 441                param->requester.gid = ino->gid;
 442                spin_unlock(&sbi->fs_lock);
 443        }
 444        path_put(&path);
 445out:
 446        return err;
 447}
 448
 449/*
 450 * Call repeatedly until it returns -EAGAIN, meaning there's nothing
 451 * more that can be done.
 452 */
 453static int autofs_dev_ioctl_expire(struct file *fp,
 454                                   struct autofs_sb_info *sbi,
 455                                   struct autofs_dev_ioctl *param)
 456{
 457        struct vfsmount *mnt;
 458        int how;
 459
 460        how = param->expire.how;
 461        mnt = fp->f_path.mnt;
 462
 463        return autofs4_do_expire_multi(sbi->sb, mnt, sbi, how);
 464}
 465
 466/* Check if autofs mount point is in use */
 467static int autofs_dev_ioctl_askumount(struct file *fp,
 468                                      struct autofs_sb_info *sbi,
 469                                      struct autofs_dev_ioctl *param)
 470{
 471        param->askumount.may_umount = 0;
 472        if (may_umount(fp->f_path.mnt))
 473                param->askumount.may_umount = 1;
 474        return 0;
 475}
 476
 477/*
 478 * Check if the given path is a mountpoint.
 479 *
 480 * If we are supplied with the file descriptor of an autofs
 481 * mount we're looking for a specific mount. In this case
 482 * the path is considered a mountpoint if it is itself a
 483 * mountpoint or contains a mount, such as a multi-mount
 484 * without a root mount. In this case we return 1 if the
 485 * path is a mount point and the super magic of the covering
 486 * mount if there is one or 0 if it isn't a mountpoint.
 487 *
 488 * If we aren't supplied with a file descriptor then we
 489 * lookup the nameidata of the path and check if it is the
 490 * root of a mount. If a type is given we are looking for
 491 * a particular autofs mount and if we don't find a match
 492 * we return fail. If the located nameidata path is the
 493 * root of a mount we return 1 along with the super magic
 494 * of the mount or 0 otherwise.
 495 *
 496 * In both cases the the device number (as returned by
 497 * new_encode_dev()) is also returned.
 498 */
 499static int autofs_dev_ioctl_ismountpoint(struct file *fp,
 500                                         struct autofs_sb_info *sbi,
 501                                         struct autofs_dev_ioctl *param)
 502{
 503        struct path path;
 504        const char *name;
 505        unsigned int type;
 506        unsigned int devid, magic;
 507        int err = -ENOENT;
 508
 509        if (param->size <= sizeof(*param)) {
 510                err = -EINVAL;
 511                goto out;
 512        }
 513
 514        name = param->path;
 515        type = param->ismountpoint.in.type;
 516
 517        param->ismountpoint.out.devid = devid = 0;
 518        param->ismountpoint.out.magic = magic = 0;
 519
 520        if (!fp || param->ioctlfd == -1) {
 521                if (autofs_type_any(type))
 522                        err = kern_path(name, LOOKUP_FOLLOW, &path);
 523                else
 524                        err = find_autofs_mount(name, &path, test_by_type, &type);
 525                if (err)
 526                        goto out;
 527                devid = new_encode_dev(path.dentry->d_sb->s_dev);
 528                err = 0;
 529                if (path.mnt->mnt_root == path.dentry) {
 530                        err = 1;
 531                        magic = path.dentry->d_sb->s_magic;
 532                }
 533        } else {
 534                dev_t dev = sbi->sb->s_dev;
 535
 536                err = find_autofs_mount(name, &path, test_by_dev, &dev);
 537                if (err)
 538                        goto out;
 539
 540                devid = new_encode_dev(dev);
 541
 542                err = have_submounts(path.dentry);
 543
 544                if (follow_down_one(&path))
 545                        magic = path.dentry->d_sb->s_magic;
 546        }
 547
 548        param->ismountpoint.out.devid = devid;
 549        param->ismountpoint.out.magic = magic;
 550        path_put(&path);
 551out:
 552        return err;
 553}
 554
 555/*
 556 * Our range of ioctl numbers isn't 0 based so we need to shift
 557 * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table
 558 * lookup.
 559 */
 560#define cmd_idx(cmd)    (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST))
 561
 562static ioctl_fn lookup_dev_ioctl(unsigned int cmd)
 563{
 564        static struct {
 565                int cmd;
 566                ioctl_fn fn;
 567        } _ioctls[] = {
 568                {cmd_idx(AUTOFS_DEV_IOCTL_VERSION_CMD), NULL},
 569                {cmd_idx(AUTOFS_DEV_IOCTL_PROTOVER_CMD),
 570                         autofs_dev_ioctl_protover},
 571                {cmd_idx(AUTOFS_DEV_IOCTL_PROTOSUBVER_CMD),
 572                         autofs_dev_ioctl_protosubver},
 573                {cmd_idx(AUTOFS_DEV_IOCTL_OPENMOUNT_CMD),
 574                         autofs_dev_ioctl_openmount},
 575                {cmd_idx(AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD),
 576                         autofs_dev_ioctl_closemount},
 577                {cmd_idx(AUTOFS_DEV_IOCTL_READY_CMD),
 578                         autofs_dev_ioctl_ready},
 579                {cmd_idx(AUTOFS_DEV_IOCTL_FAIL_CMD),
 580                         autofs_dev_ioctl_fail},
 581                {cmd_idx(AUTOFS_DEV_IOCTL_SETPIPEFD_CMD),
 582                         autofs_dev_ioctl_setpipefd},
 583                {cmd_idx(AUTOFS_DEV_IOCTL_CATATONIC_CMD),
 584                         autofs_dev_ioctl_catatonic},
 585                {cmd_idx(AUTOFS_DEV_IOCTL_TIMEOUT_CMD),
 586                         autofs_dev_ioctl_timeout},
 587                {cmd_idx(AUTOFS_DEV_IOCTL_REQUESTER_CMD),
 588                         autofs_dev_ioctl_requester},
 589                {cmd_idx(AUTOFS_DEV_IOCTL_EXPIRE_CMD),
 590                         autofs_dev_ioctl_expire},
 591                {cmd_idx(AUTOFS_DEV_IOCTL_ASKUMOUNT_CMD),
 592                         autofs_dev_ioctl_askumount},
 593                {cmd_idx(AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD),
 594                         autofs_dev_ioctl_ismountpoint}
 595        };
 596        unsigned int idx = cmd_idx(cmd);
 597
 598        return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx].fn;
 599}
 600
 601/* ioctl dispatcher */
 602static int _autofs_dev_ioctl(unsigned int command, struct autofs_dev_ioctl __user *user)
 603{
 604        struct autofs_dev_ioctl *param;
 605        struct file *fp;
 606        struct autofs_sb_info *sbi;
 607        unsigned int cmd_first, cmd;
 608        ioctl_fn fn = NULL;
 609        int err = 0;
 610
 611        /* only root can play with this */
 612        if (!capable(CAP_SYS_ADMIN))
 613                return -EPERM;
 614
 615        cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST);
 616        cmd = _IOC_NR(command);
 617
 618        if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) ||
 619            cmd - cmd_first >= AUTOFS_DEV_IOCTL_IOC_COUNT) {
 620                return -ENOTTY;
 621        }
 622
 623        /* Copy the parameters into kernel space. */
 624        param = copy_dev_ioctl(user);
 625        if (IS_ERR(param))
 626                return PTR_ERR(param);
 627
 628        err = validate_dev_ioctl(command, param);
 629        if (err)
 630                goto out;
 631
 632        /* The validate routine above always sets the version */
 633        if (cmd == AUTOFS_DEV_IOCTL_VERSION_CMD)
 634                goto done;
 635
 636        fn = lookup_dev_ioctl(cmd);
 637        if (!fn) {
 638                AUTOFS_WARN("unknown command 0x%08x", command);
 639                return -ENOTTY;
 640        }
 641
 642        fp = NULL;
 643        sbi = NULL;
 644
 645        /*
 646         * For obvious reasons the openmount can't have a file
 647         * descriptor yet. We don't take a reference to the
 648         * file during close to allow for immediate release.
 649         */
 650        if (cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD &&
 651            cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) {
 652                fp = fget(param->ioctlfd);
 653                if (!fp) {
 654                        if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD)
 655                                goto cont;
 656                        err = -EBADF;
 657                        goto out;
 658                }
 659
 660                if (!fp->f_op) {
 661                        err = -ENOTTY;
 662                        fput(fp);
 663                        goto out;
 664                }
 665
 666                sbi = autofs_dev_ioctl_sbi(fp);
 667                if (!sbi || sbi->magic != AUTOFS_SBI_MAGIC) {
 668                        err = -EINVAL;
 669                        fput(fp);
 670                        goto out;
 671                }
 672
 673                /*
 674                 * Admin needs to be able to set the mount catatonic in
 675                 * order to be able to perform the re-open.
 676                 */
 677                if (!autofs4_oz_mode(sbi) &&
 678                    cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) {
 679                        err = -EACCES;
 680                        fput(fp);
 681                        goto out;
 682                }
 683        }
 684cont:
 685        err = fn(fp, sbi, param);
 686
 687        if (fp)
 688                fput(fp);
 689done:
 690        if (err >= 0 && copy_to_user(user, param, AUTOFS_DEV_IOCTL_SIZE))
 691                err = -EFAULT;
 692out:
 693        free_dev_ioctl(param);
 694        return err;
 695}
 696
 697static long autofs_dev_ioctl(struct file *file, uint command, ulong u)
 698{
 699        int err;
 700        err = _autofs_dev_ioctl(command, (struct autofs_dev_ioctl __user *) u);
 701        return (long) err;
 702}
 703
 704#ifdef CONFIG_COMPAT
 705static long autofs_dev_ioctl_compat(struct file *file, uint command, ulong u)
 706{
 707        return (long) autofs_dev_ioctl(file, command, (ulong) compat_ptr(u));
 708}
 709#else
 710#define autofs_dev_ioctl_compat NULL
 711#endif
 712
 713static const struct file_operations _dev_ioctl_fops = {
 714        .unlocked_ioctl  = autofs_dev_ioctl,
 715        .compat_ioctl = autofs_dev_ioctl_compat,
 716        .owner   = THIS_MODULE,
 717        .llseek = noop_llseek,
 718};
 719
 720static struct miscdevice _autofs_dev_ioctl_misc = {
 721        .minor          = AUTOFS_MINOR,
 722        .name           = AUTOFS_DEVICE_NAME,
 723        .fops           = &_dev_ioctl_fops
 724};
 725
 726MODULE_ALIAS_MISCDEV(AUTOFS_MINOR);
 727MODULE_ALIAS("devname:autofs");
 728
 729/* Register/deregister misc character device */
 730int autofs_dev_ioctl_init(void)
 731{
 732        int r;
 733
 734        r = misc_register(&_autofs_dev_ioctl_misc);
 735        if (r) {
 736                AUTOFS_ERROR("misc_register failed for control device");
 737                return r;
 738        }
 739
 740        return 0;
 741}
 742
 743void autofs_dev_ioctl_exit(void)
 744{
 745        misc_deregister(&_autofs_dev_ioctl_misc);
 746        return;
 747}
 748
 749
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