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
 224static void autofs_dev_ioctl_fd_install(unsigned int fd, struct file *file)
 225{
 226        struct files_struct *files = current->files;
 227        struct fdtable *fdt;
 228
 229        spin_lock(&files->file_lock);
 230        fdt = files_fdtable(files);
 231        BUG_ON(fdt->fd[fd] != NULL);
 232        rcu_assign_pointer(fdt->fd[fd], file);
 233        __set_close_on_exec(fd, fdt);
 234        spin_unlock(&files->file_lock);
 235}
 236
 237
 238/*
 239 * Open a file descriptor on the autofs mount point corresponding
 240 * to the given path and device number (aka. new_encode_dev(sb->s_dev)).
 241 */
 242static int autofs_dev_ioctl_open_mountpoint(const char *name, dev_t devid)
 243{
 244        int err, fd;
 245
 246        fd = get_unused_fd();
 247        if (likely(fd >= 0)) {
 248                struct file *filp;
 249                struct path path;
 250
 251                err = find_autofs_mount(name, &path, test_by_dev, &devid);
 252                if (err)
 253                        goto out;
 254
 255                /*
 256                 * Find autofs super block that has the device number
 257                 * corresponding to the autofs fs we want to open.
 258                 */
 259
 260                filp = dentry_open(&path, O_RDONLY, current_cred());
 261                path_put(&path);
 262                if (IS_ERR(filp)) {
 263                        err = PTR_ERR(filp);
 264                        goto out;
 265                }
 266
 267                autofs_dev_ioctl_fd_install(fd, filp);
 268        }
 269
 270        return fd;
 271
 272out:
 273        put_unused_fd(fd);
 274        return err;
 275}
 276
 277/* Open a file descriptor on an autofs mount point */
 278static int autofs_dev_ioctl_openmount(struct file *fp,
 279                                      struct autofs_sb_info *sbi,
 280                                      struct autofs_dev_ioctl *param)
 281{
 282        const char *path;
 283        dev_t devid;
 284        int err, fd;
 285
 286        /* param->path has already been checked */
 287        if (!param->openmount.devid)
 288                return -EINVAL;
 289
 290        param->ioctlfd = -1;
 291
 292        path = param->path;
 293        devid = new_decode_dev(param->openmount.devid);
 294
 295        err = 0;
 296        fd = autofs_dev_ioctl_open_mountpoint(path, devid);
 297        if (unlikely(fd < 0)) {
 298                err = fd;
 299                goto out;
 300        }
 301
 302        param->ioctlfd = fd;
 303out:
 304        return err;
 305}
 306
 307/* Close file descriptor allocated above (user can also use close(2)). */
 308static int autofs_dev_ioctl_closemount(struct file *fp,
 309                                       struct autofs_sb_info *sbi,
 310                                       struct autofs_dev_ioctl *param)
 311{
 312        return sys_close(param->ioctlfd);
 313}
 314
 315/*
 316 * Send "ready" status for an existing wait (either a mount or an expire
 317 * request).
 318 */
 319static int autofs_dev_ioctl_ready(struct file *fp,
 320                                  struct autofs_sb_info *sbi,
 321                                  struct autofs_dev_ioctl *param)
 322{
 323        autofs_wqt_t token;
 324
 325        token = (autofs_wqt_t) param->ready.token;
 326        return autofs4_wait_release(sbi, token, 0);
 327}
 328
 329/*
 330 * Send "fail" status for an existing wait (either a mount or an expire
 331 * request).
 332 */
 333static int autofs_dev_ioctl_fail(struct file *fp,
 334                                 struct autofs_sb_info *sbi,
 335                                 struct autofs_dev_ioctl *param)
 336{
 337        autofs_wqt_t token;
 338        int status;
 339
 340        token = (autofs_wqt_t) param->fail.token;
 341        status = param->fail.status ? param->fail.status : -ENOENT;
 342        return autofs4_wait_release(sbi, token, status);
 343}
 344
 345/*
 346 * Set the pipe fd for kernel communication to the daemon.
 347 *
 348 * Normally this is set at mount using an option but if we
 349 * are reconnecting to a busy mount then we need to use this
 350 * to tell the autofs mount about the new kernel pipe fd. In
 351 * order to protect mounts against incorrectly setting the
 352 * pipefd we also require that the autofs mount be catatonic.
 353 *
 354 * This also sets the process group id used to identify the
 355 * controlling process (eg. the owning automount(8) daemon).
 356 */
 357static int autofs_dev_ioctl_setpipefd(struct file *fp,
 358                                      struct autofs_sb_info *sbi,
 359                                      struct autofs_dev_ioctl *param)
 360{
 361        int pipefd;
 362        int err = 0;
 363
 364        if (param->setpipefd.pipefd == -1)
 365                return -EINVAL;
 366
 367        pipefd = param->setpipefd.pipefd;
 368
 369        mutex_lock(&sbi->wq_mutex);
 370        if (!sbi->catatonic) {
 371                mutex_unlock(&sbi->wq_mutex);
 372                return -EBUSY;
 373        } else {
 374                struct file *pipe = fget(pipefd);
 375                if (!pipe) {
 376                        err = -EBADF;
 377                        goto out;
 378                }
 379                if (autofs_prepare_pipe(pipe) < 0) {
 380                        err = -EPIPE;
 381                        fput(pipe);
 382                        goto out;
 383                }
 384                sbi->oz_pgrp = task_pgrp_nr(current);
 385                sbi->pipefd = pipefd;
 386                sbi->pipe = pipe;
 387                sbi->catatonic = 0;
 388        }
 389out:
 390        mutex_unlock(&sbi->wq_mutex);
 391        return err;
 392}
 393
 394/*
 395 * Make the autofs mount point catatonic, no longer responsive to
 396 * mount requests. Also closes the kernel pipe file descriptor.
 397 */
 398static int autofs_dev_ioctl_catatonic(struct file *fp,
 399                                      struct autofs_sb_info *sbi,
 400                                      struct autofs_dev_ioctl *param)
 401{
 402        autofs4_catatonic_mode(sbi);
 403        return 0;
 404}
 405
 406/* Set the autofs mount timeout */
 407static int autofs_dev_ioctl_timeout(struct file *fp,
 408                                    struct autofs_sb_info *sbi,
 409                                    struct autofs_dev_ioctl *param)
 410{
 411        unsigned long timeout;
 412
 413        timeout = param->timeout.timeout;
 414        param->timeout.timeout = sbi->exp_timeout / HZ;
 415        sbi->exp_timeout = timeout * HZ;
 416        return 0;
 417}
 418
 419/*
 420 * Return the uid and gid of the last request for the mount
 421 *
 422 * When reconstructing an autofs mount tree with active mounts
 423 * we need to re-connect to mounts that may have used the original
 424 * process uid and gid (or string variations of them) for mount
 425 * lookups within the map entry.
 426 */
 427static int autofs_dev_ioctl_requester(struct file *fp,
 428                                      struct autofs_sb_info *sbi,
 429                                      struct autofs_dev_ioctl *param)
 430{
 431        struct autofs_info *ino;
 432        struct path path;
 433        dev_t devid;
 434        int err = -ENOENT;
 435
 436        if (param->size <= sizeof(*param)) {
 437                err = -EINVAL;
 438                goto out;
 439        }
 440
 441        devid = sbi->sb->s_dev;
 442
 443        param->requester.uid = param->requester.gid = -1;
 444
 445        err = find_autofs_mount(param->path, &path, test_by_dev, &devid);
 446        if (err)
 447                goto out;
 448
 449        ino = autofs4_dentry_ino(path.dentry);
 450        if (ino) {
 451                err = 0;
 452                autofs4_expire_wait(path.dentry);
 453                spin_lock(&sbi->fs_lock);
 454                param->requester.uid = ino->uid;
 455                param->requester.gid = ino->gid;
 456                spin_unlock(&sbi->fs_lock);
 457        }
 458        path_put(&path);
 459out:
 460        return err;
 461}
 462
 463/*
 464 * Call repeatedly until it returns -EAGAIN, meaning there's nothing
 465 * more that can be done.
 466 */
 467static int autofs_dev_ioctl_expire(struct file *fp,
 468                                   struct autofs_sb_info *sbi,
 469                                   struct autofs_dev_ioctl *param)
 470{
 471        struct vfsmount *mnt;
 472        int how;
 473
 474        how = param->expire.how;
 475        mnt = fp->f_path.mnt;
 476
 477        return autofs4_do_expire_multi(sbi->sb, mnt, sbi, how);
 478}
 479
 480/* Check if autofs mount point is in use */
 481static int autofs_dev_ioctl_askumount(struct file *fp,
 482                                      struct autofs_sb_info *sbi,
 483                                      struct autofs_dev_ioctl *param)
 484{
 485        param->askumount.may_umount = 0;
 486        if (may_umount(fp->f_path.mnt))
 487                param->askumount.may_umount = 1;
 488        return 0;
 489}
 490
 491/*
 492 * Check if the given path is a mountpoint.
 493 *
 494 * If we are supplied with the file descriptor of an autofs
 495 * mount we're looking for a specific mount. In this case
 496 * the path is considered a mountpoint if it is itself a
 497 * mountpoint or contains a mount, such as a multi-mount
 498 * without a root mount. In this case we return 1 if the
 499 * path is a mount point and the super magic of the covering
 500 * mount if there is one or 0 if it isn't a mountpoint.
 501 *
 502 * If we aren't supplied with a file descriptor then we
 503 * lookup the nameidata of the path and check if it is the
 504 * root of a mount. If a type is given we are looking for
 505 * a particular autofs mount and if we don't find a match
 506 * we return fail. If the located nameidata path is the
 507 * root of a mount we return 1 along with the super magic
 508 * of the mount or 0 otherwise.
 509 *
 510 * In both cases the the device number (as returned by
 511 * new_encode_dev()) is also returned.
 512 */
 513static int autofs_dev_ioctl_ismountpoint(struct file *fp,
 514                                         struct autofs_sb_info *sbi,
 515                                         struct autofs_dev_ioctl *param)
 516{
 517        struct path path;
 518        const char *name;
 519        unsigned int type;
 520        unsigned int devid, magic;
 521        int err = -ENOENT;
 522
 523        if (param->size <= sizeof(*param)) {
 524                err = -EINVAL;
 525                goto out;
 526        }
 527
 528        name = param->path;
 529        type = param->ismountpoint.in.type;
 530
 531        param->ismountpoint.out.devid = devid = 0;
 532        param->ismountpoint.out.magic = magic = 0;
 533
 534        if (!fp || param->ioctlfd == -1) {
 535                if (autofs_type_any(type))
 536                        err = kern_path(name, LOOKUP_FOLLOW, &path);
 537                else
 538                        err = find_autofs_mount(name, &path, test_by_type, &type);
 539                if (err)
 540                        goto out;
 541                devid = new_encode_dev(path.dentry->d_sb->s_dev);
 542                err = 0;
 543                if (path.mnt->mnt_root == path.dentry) {
 544                        err = 1;
 545                        magic = path.dentry->d_sb->s_magic;
 546                }
 547        } else {
 548                dev_t dev = sbi->sb->s_dev;
 549
 550                err = find_autofs_mount(name, &path, test_by_dev, &dev);
 551                if (err)
 552                        goto out;
 553
 554                devid = new_encode_dev(dev);
 555
 556                err = have_submounts(path.dentry);
 557
 558                if (follow_down_one(&path))
 559                        magic = path.dentry->d_sb->s_magic;
 560        }
 561
 562        param->ismountpoint.out.devid = devid;
 563        param->ismountpoint.out.magic = magic;
 564        path_put(&path);
 565out:
 566        return err;
 567}
 568
 569/*
 570 * Our range of ioctl numbers isn't 0 based so we need to shift
 571 * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table
 572 * lookup.
 573 */
 574#define cmd_idx(cmd)    (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST))
 575
 576static ioctl_fn lookup_dev_ioctl(unsigned int cmd)
 577{
 578        static struct {
 579                int cmd;
 580                ioctl_fn fn;
 581        } _ioctls[] = {
 582                {cmd_idx(AUTOFS_DEV_IOCTL_VERSION_CMD), NULL},
 583                {cmd_idx(AUTOFS_DEV_IOCTL_PROTOVER_CMD),
 584                         autofs_dev_ioctl_protover},
 585                {cmd_idx(AUTOFS_DEV_IOCTL_PROTOSUBVER_CMD),
 586                         autofs_dev_ioctl_protosubver},
 587                {cmd_idx(AUTOFS_DEV_IOCTL_OPENMOUNT_CMD),
 588                         autofs_dev_ioctl_openmount},
 589                {cmd_idx(AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD),
 590                         autofs_dev_ioctl_closemount},
 591                {cmd_idx(AUTOFS_DEV_IOCTL_READY_CMD),
 592                         autofs_dev_ioctl_ready},
 593                {cmd_idx(AUTOFS_DEV_IOCTL_FAIL_CMD),
 594                         autofs_dev_ioctl_fail},
 595                {cmd_idx(AUTOFS_DEV_IOCTL_SETPIPEFD_CMD),
 596                         autofs_dev_ioctl_setpipefd},
 597                {cmd_idx(AUTOFS_DEV_IOCTL_CATATONIC_CMD),
 598                         autofs_dev_ioctl_catatonic},
 599                {cmd_idx(AUTOFS_DEV_IOCTL_TIMEOUT_CMD),
 600                         autofs_dev_ioctl_timeout},
 601                {cmd_idx(AUTOFS_DEV_IOCTL_REQUESTER_CMD),
 602                         autofs_dev_ioctl_requester},
 603                {cmd_idx(AUTOFS_DEV_IOCTL_EXPIRE_CMD),
 604                         autofs_dev_ioctl_expire},
 605                {cmd_idx(AUTOFS_DEV_IOCTL_ASKUMOUNT_CMD),
 606                         autofs_dev_ioctl_askumount},
 607                {cmd_idx(AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD),
 608                         autofs_dev_ioctl_ismountpoint}
 609        };
 610        unsigned int idx = cmd_idx(cmd);
 611
 612        return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx].fn;
 613}
 614
 615/* ioctl dispatcher */
 616static int _autofs_dev_ioctl(unsigned int command, struct autofs_dev_ioctl __user *user)
 617{
 618        struct autofs_dev_ioctl *param;
 619        struct file *fp;
 620        struct autofs_sb_info *sbi;
 621        unsigned int cmd_first, cmd;
 622        ioctl_fn fn = NULL;
 623        int err = 0;
 624
 625        /* only root can play with this */
 626        if (!capable(CAP_SYS_ADMIN))
 627                return -EPERM;
 628
 629        cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST);
 630        cmd = _IOC_NR(command);
 631
 632        if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) ||
 633            cmd - cmd_first >= AUTOFS_DEV_IOCTL_IOC_COUNT) {
 634                return -ENOTTY;
 635        }
 636
 637        /* Copy the parameters into kernel space. */
 638        param = copy_dev_ioctl(user);
 639        if (IS_ERR(param))
 640                return PTR_ERR(param);
 641
 642        err = validate_dev_ioctl(command, param);
 643        if (err)
 644                goto out;
 645
 646        /* The validate routine above always sets the version */
 647        if (cmd == AUTOFS_DEV_IOCTL_VERSION_CMD)
 648                goto done;
 649
 650        fn = lookup_dev_ioctl(cmd);
 651        if (!fn) {
 652                AUTOFS_WARN("unknown command 0x%08x", command);
 653                return -ENOTTY;
 654        }
 655
 656        fp = NULL;
 657        sbi = NULL;
 658
 659        /*
 660         * For obvious reasons the openmount can't have a file
 661         * descriptor yet. We don't take a reference to the
 662         * file during close to allow for immediate release.
 663         */
 664        if (cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD &&
 665            cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) {
 666                fp = fget(param->ioctlfd);
 667                if (!fp) {
 668                        if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD)
 669                                goto cont;
 670                        err = -EBADF;
 671                        goto out;
 672                }
 673
 674                if (!fp->f_op) {
 675                        err = -ENOTTY;
 676                        fput(fp);
 677                        goto out;
 678                }
 679
 680                sbi = autofs_dev_ioctl_sbi(fp);
 681                if (!sbi || sbi->magic != AUTOFS_SBI_MAGIC) {
 682                        err = -EINVAL;
 683                        fput(fp);
 684                        goto out;
 685                }
 686
 687                /*
 688                 * Admin needs to be able to set the mount catatonic in
 689                 * order to be able to perform the re-open.
 690                 */
 691                if (!autofs4_oz_mode(sbi) &&
 692                    cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) {
 693                        err = -EACCES;
 694                        fput(fp);
 695                        goto out;
 696                }
 697        }
 698cont:
 699        err = fn(fp, sbi, param);
 700
 701        if (fp)
 702                fput(fp);
 703done:
 704        if (err >= 0 && copy_to_user(user, param, AUTOFS_DEV_IOCTL_SIZE))
 705                err = -EFAULT;
 706out:
 707        free_dev_ioctl(param);
 708        return err;
 709}
 710
 711static long autofs_dev_ioctl(struct file *file, uint command, ulong u)
 712{
 713        int err;
 714        err = _autofs_dev_ioctl(command, (struct autofs_dev_ioctl __user *) u);
 715        return (long) err;
 716}
 717
 718#ifdef CONFIG_COMPAT
 719static long autofs_dev_ioctl_compat(struct file *file, uint command, ulong u)
 720{
 721        return (long) autofs_dev_ioctl(file, command, (ulong) compat_ptr(u));
 722}
 723#else
 724#define autofs_dev_ioctl_compat NULL
 725#endif
 726
 727static const struct file_operations _dev_ioctl_fops = {
 728        .unlocked_ioctl  = autofs_dev_ioctl,
 729        .compat_ioctl = autofs_dev_ioctl_compat,
 730        .owner   = THIS_MODULE,
 731        .llseek = noop_llseek,
 732};
 733
 734static struct miscdevice _autofs_dev_ioctl_misc = {
 735        .minor          = AUTOFS_MINOR,
 736        .name           = AUTOFS_DEVICE_NAME,
 737        .fops           = &_dev_ioctl_fops
 738};
 739
 740MODULE_ALIAS_MISCDEV(AUTOFS_MINOR);
 741MODULE_ALIAS("devname:autofs");
 742
 743/* Register/deregister misc character device */
 744int autofs_dev_ioctl_init(void)
 745{
 746        int r;
 747
 748        r = misc_register(&_autofs_dev_ioctl_misc);
 749        if (r) {
 750                AUTOFS_ERROR("misc_register failed for control device");
 751                return r;
 752        }
 753
 754        return 0;
 755}
 756
 757void autofs_dev_ioctl_exit(void)
 758{
 759        misc_deregister(&_autofs_dev_ioctl_misc);
 760        return;
 761}
 762
 763
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