blob: a16214109d31ef8c7f0897eb6389b16872a2392d [file] [log] [blame]
Ian Kent8d7b48e2008-10-15 22:02:54 -07001/*
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>
Ian Kent8d7b48e2008-10-15 22:02:54 -070022#include <linux/magic.h>
23#include <linux/dcache.h>
24#include <linux/uaccess.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090025#include <linux/slab.h>
Ian Kent8d7b48e2008-10-15 22:02:54 -070026
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 */
Al Viro3eac8772009-04-07 11:12:46 -040057static int invalid_str(char *str, size_t size)
Ian Kent8d7b48e2008-10-15 22:02:54 -070058{
Al Viro3eac8772009-04-07 11:12:46 -040059 if (memchr(str, 0, size))
60 return 0;
Ian Kent8d7b48e2008-10-15 22:02:54 -070061 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{
Julia Lawall7ca5ca62010-05-26 14:42:13 -070098 struct autofs_dev_ioctl tmp;
Ian Kent8d7b48e2008-10-15 22:02:54 -070099
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
Julia Lawall7ca5ca62010-05-26 14:42:13 -0700106 return memdup_user(in, tmp.size);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700107}
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
Ian Kentbae8ec62009-01-06 14:42:09 -0800117 * check that it is terminated and contains at least one "/".
Ian Kent8d7b48e2008-10-15 22:02:54 -0700118 */
119static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param)
120{
Ian Kent96b03172008-11-06 12:53:23 -0800121 int err;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700122
Ian Kent96b03172008-11-06 12:53:23 -0800123 err = check_dev_ioctl_version(cmd, param);
124 if (err) {
Ian Kent8d7b48e2008-10-15 22:02:54 -0700125 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)) {
Al Viro3eac8772009-04-07 11:12:46 -0400131 err = invalid_str(param->path, param->size - sizeof(*param));
Ian Kent8d7b48e2008-10-15 22:02:54 -0700132 if (err) {
Ian Kentbae8ec62009-01-06 14:42:09 -0800133 AUTOFS_WARN(
134 "path string terminator missing for cmd(0x%08x)",
135 cmd);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700136 goto out;
137 }
138
Ian Kentbae8ec62009-01-06 14:42:09 -0800139 err = check_name(param->path);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700140 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{
Ian Kent730c9ee2009-01-06 14:42:06 -0800173 param->protover.version = sbi->version;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700174 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{
Ian Kent730c9ee2009-01-06 14:42:06 -0800182 param->protosubver.sub_version = sbi->sub_version;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700183 return 0;
184}
185
Al Viro4e44b682009-04-07 11:08:56 -0400186static int find_autofs_mount(const char *pathname,
187 struct path *res,
188 int test(struct path *path, void *data),
189 void *data)
Ian Kent8d7b48e2008-10-15 22:02:54 -0700190{
Al Viro4e44b682009-04-07 11:08:56 -0400191 struct path path;
192 int err = kern_path(pathname, 0, &path);
193 if (err)
194 return err;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700195 err = -ENOENT;
Al Viro4e44b682009-04-07 11:08:56 -0400196 while (path.dentry == path.mnt->mnt_root) {
Al Virod8c95842011-12-07 18:16:57 -0500197 if (path.dentry->d_sb->s_magic == AUTOFS_SUPER_MAGIC) {
Al Viro4e44b682009-04-07 11:08:56 -0400198 if (test(&path, data)) {
199 path_get(&path);
200 if (!err) /* already found some */
201 path_put(res);
202 *res = path;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700203 err = 0;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700204 }
205 }
Al Virobab77eb2009-04-18 03:26:48 -0400206 if (!follow_up(&path))
Al Viro4e44b682009-04-07 11:08:56 -0400207 break;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700208 }
Al Viro4e44b682009-04-07 11:08:56 -0400209 path_put(&path);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700210 return err;
211}
212
Al Viro4e44b682009-04-07 11:08:56 -0400213static int test_by_dev(struct path *path, void *p)
Ian Kent8d7b48e2008-10-15 22:02:54 -0700214{
Al Virod8c95842011-12-07 18:16:57 -0500215 return path->dentry->d_sb->s_dev == *(dev_t *)p;
Al Viro4e44b682009-04-07 11:08:56 -0400216}
Ian Kent8d7b48e2008-10-15 22:02:54 -0700217
Al Viro4e44b682009-04-07 11:08:56 -0400218static 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;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700222}
223
Ian Kent8d7b48e2008-10-15 22:02:54 -0700224/*
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 */
Al Viro4e44b682009-04-07 11:08:56 -0400228static int autofs_dev_ioctl_open_mountpoint(const char *name, dev_t devid)
Ian Kent8d7b48e2008-10-15 22:02:54 -0700229{
Ian Kent8d7b48e2008-10-15 22:02:54 -0700230 int err, fd;
231
Al Viroc921b402012-08-12 18:04:37 -0400232 fd = get_unused_fd_flags(O_CLOEXEC);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700233 if (likely(fd >= 0)) {
Al Viro4e44b682009-04-07 11:08:56 -0400234 struct file *filp;
235 struct path path;
236
237 err = find_autofs_mount(name, &path, test_by_dev, &devid);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700238 if (err)
239 goto out;
240
241 /*
Al Viro4e44b682009-04-07 11:08:56 -0400242 * Find autofs super block that has the device number
Ian Kent8d7b48e2008-10-15 22:02:54 -0700243 * corresponding to the autofs fs we want to open.
244 */
Ian Kent8d7b48e2008-10-15 22:02:54 -0700245
Al Viro765927b2012-06-26 21:58:53 +0400246 filp = dentry_open(&path, O_RDONLY, current_cred());
247 path_put(&path);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700248 if (IS_ERR(filp)) {
249 err = PTR_ERR(filp);
250 goto out;
251 }
252
Al Viroc921b402012-08-12 18:04:37 -0400253 fd_install(fd, filp);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700254 }
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 */
Ian Kent730c9ee2009-01-06 14:42:06 -0800273 if (!param->openmount.devid)
Ian Kent8d7b48e2008-10-15 22:02:54 -0700274 return -EINVAL;
275
276 param->ioctlfd = -1;
277
278 path = param->path;
Al Viro4e44b682009-04-07 11:08:56 -0400279 devid = new_decode_dev(param->openmount.devid);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700280
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
Ian Kent730c9ee2009-01-06 14:42:06 -0800311 token = (autofs_wqt_t) param->ready.token;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700312 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
Ian Kent730c9ee2009-01-06 14:42:06 -0800326 token = (autofs_wqt_t) param->fail.token;
327 status = param->fail.status ? param->fail.status : -ENOENT;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700328 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
Ian Kent730c9ee2009-01-06 14:42:06 -0800350 if (param->setpipefd.pipefd == -1)
Ian Kent8d7b48e2008-10-15 22:02:54 -0700351 return -EINVAL;
352
Ian Kent730c9ee2009-01-06 14:42:06 -0800353 pipefd = param->setpipefd.pipefd;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700354
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);
Jesper Juhl3dc8fe42011-03-25 01:51:37 +0800361 if (!pipe) {
362 err = -EBADF;
363 goto out;
364 }
Linus Torvalds64f371b2012-04-29 13:30:08 -0700365 if (autofs_prepare_pipe(pipe) < 0) {
Ian Kent8d7b48e2008-10-15 22:02:54 -0700366 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
Ian Kent730c9ee2009-01-06 14:42:06 -0800399 timeout = param->timeout.timeout;
400 param->timeout.timeout = sbi->exp_timeout / HZ;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700401 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;
Al Viro4e44b682009-04-07 11:08:56 -0400418 struct path path;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700419 dev_t devid;
420 int err = -ENOENT;
421
422 if (param->size <= sizeof(*param)) {
423 err = -EINVAL;
424 goto out;
425 }
426
Al Viro4e44b682009-04-07 11:08:56 -0400427 devid = sbi->sb->s_dev;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700428
Ian Kent730c9ee2009-01-06 14:42:06 -0800429 param->requester.uid = param->requester.gid = -1;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700430
Al Viro4e44b682009-04-07 11:08:56 -0400431 err = find_autofs_mount(param->path, &path, test_by_dev, &devid);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700432 if (err)
433 goto out;
434
Al Viro4e44b682009-04-07 11:08:56 -0400435 ino = autofs4_dentry_ino(path.dentry);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700436 if (ino) {
437 err = 0;
Al Viro4e44b682009-04-07 11:08:56 -0400438 autofs4_expire_wait(path.dentry);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700439 spin_lock(&sbi->fs_lock);
Ian Kent730c9ee2009-01-06 14:42:06 -0800440 param->requester.uid = ino->uid;
441 param->requester.gid = ino->gid;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700442 spin_unlock(&sbi->fs_lock);
443 }
Al Viro4e44b682009-04-07 11:08:56 -0400444 path_put(&path);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700445out:
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{
Ian Kent8d7b48e2008-10-15 22:02:54 -0700457 struct vfsmount *mnt;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700458 int how;
459
Ian Kent730c9ee2009-01-06 14:42:06 -0800460 how = param->expire.how;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700461 mnt = fp->f_path.mnt;
462
Ian Kent56fcef72009-03-31 15:24:43 -0700463 return autofs4_do_expire_multi(sbi->sb, mnt, sbi, how);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700464}
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{
Ian Kent730c9ee2009-01-06 14:42:06 -0800471 param->askumount.may_umount = 0;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700472 if (may_umount(fp->f_path.mnt))
Ian Kent730c9ee2009-01-06 14:42:06 -0800473 param->askumount.may_umount = 1;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700474 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{
Al Viro4e44b682009-04-07 11:08:56 -0400503 struct path path;
504 const char *name;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700505 unsigned int type;
Ian Kent730c9ee2009-01-06 14:42:06 -0800506 unsigned int devid, magic;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700507 int err = -ENOENT;
508
509 if (param->size <= sizeof(*param)) {
510 err = -EINVAL;
511 goto out;
512 }
513
Al Viro4e44b682009-04-07 11:08:56 -0400514 name = param->path;
Ian Kent730c9ee2009-01-06 14:42:06 -0800515 type = param->ismountpoint.in.type;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700516
Ian Kent730c9ee2009-01-06 14:42:06 -0800517 param->ismountpoint.out.devid = devid = 0;
518 param->ismountpoint.out.magic = magic = 0;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700519
520 if (!fp || param->ioctlfd == -1) {
Al Viro4e44b682009-04-07 11:08:56 -0400521 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;
Al Virod8c95842011-12-07 18:16:57 -0500527 devid = new_encode_dev(path.dentry->d_sb->s_dev);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700528 err = 0;
Al Virof598f9f2010-01-23 20:08:53 -0500529 if (path.mnt->mnt_root == path.dentry) {
Ian Kent8d7b48e2008-10-15 22:02:54 -0700530 err = 1;
Al Virod8c95842011-12-07 18:16:57 -0500531 magic = path.dentry->d_sb->s_magic;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700532 }
533 } else {
Al Viro4e44b682009-04-07 11:08:56 -0400534 dev_t dev = sbi->sb->s_dev;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700535
Al Viro4e44b682009-04-07 11:08:56 -0400536 err = find_autofs_mount(name, &path, test_by_dev, &dev);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700537 if (err)
538 goto out;
539
Al Viro4e44b682009-04-07 11:08:56 -0400540 devid = new_encode_dev(dev);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700541
Al Viro4e44b682009-04-07 11:08:56 -0400542 err = have_submounts(path.dentry);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700543
David Howellscc53ce52011-01-14 18:45:26 +0000544 if (follow_down_one(&path))
Al Virod8c95842011-12-07 18:16:57 -0500545 magic = path.dentry->d_sb->s_magic;
Ian Kent8d7b48e2008-10-15 22:02:54 -0700546 }
547
Ian Kent730c9ee2009-01-06 14:42:06 -0800548 param->ismountpoint.out.devid = devid;
549 param->ismountpoint.out.magic = magic;
Al Viro4e44b682009-04-07 11:08:56 -0400550 path_put(&path);
Ian Kent8d7b48e2008-10-15 22:02:54 -0700551out:
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,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200717 .llseek = noop_llseek,
Ian Kent8d7b48e2008-10-15 22:02:54 -0700718};
719
720static struct miscdevice _autofs_dev_ioctl_misc = {
Kay Sievers578454f2010-05-20 18:07:20 +0200721 .minor = AUTOFS_MINOR,
Ian Kent8d7b48e2008-10-15 22:02:54 -0700722 .name = AUTOFS_DEVICE_NAME,
723 .fops = &_dev_ioctl_fops
724};
725
Kay Sievers578454f2010-05-20 18:07:20 +0200726MODULE_ALIAS_MISCDEV(AUTOFS_MINOR);
727MODULE_ALIAS("devname:autofs");
728
Ian Kent8d7b48e2008-10-15 22:02:54 -0700729/* 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