1/*-
2 * Copyright (c) 2014 The FreeBSD Foundation
3 *
4 * This software was developed by Edward Tomasz Napierala under sponsorship
5 * from the FreeBSD Foundation.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 */
29/*-
30 * Copyright (c) 1989, 1991, 1993, 1995
31 *	The Regents of the University of California.  All rights reserved.
32 *
33 * This code is derived from software contributed to Berkeley by
34 * Rick Macklem at The University of Guelph.
35 *
36 * Redistribution and use in source and binary forms, with or without
37 * modification, are permitted provided that the following conditions
38 * are met:
39 * 1. Redistributions of source code must retain the above copyright
40 *    notice, this list of conditions and the following disclaimer.
41 * 2. Redistributions in binary form must reproduce the above copyright
42 *    notice, this list of conditions and the following disclaimer in the
43 *    documentation and/or other materials provided with the distribution.
44 * 3. Neither the name of the University nor the names of its contributors
45 *    may be used to endorse or promote products derived from this software
46 *    without specific prior written permission.
47 *
48 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
49 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
51 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
52 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
53 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
54 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
55 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
56 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
57 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58 * SUCH DAMAGE.
59 *
60 */
61
62#include <sys/cdefs.h>
63__FBSDID("$FreeBSD$");
64
65#include <sys/param.h>
66#include <sys/systm.h>
67#include <sys/buf.h>
68#include <sys/conf.h>
69#include <sys/dirent.h>
70#include <sys/ioccom.h>
71#include <sys/kernel.h>
72#include <sys/module.h>
73#include <sys/mount.h>
74#include <sys/refcount.h>
75#include <sys/sx.h>
76#include <sys/sysctl.h>
77#include <sys/syscallsubr.h>
78#include <sys/taskqueue.h>
79#include <sys/tree.h>
80#include <sys/vnode.h>
81#include <machine/atomic.h>
82#include <vm/uma.h>
83
84#include <fs/autofs/autofs.h>
85#include <fs/autofs/autofs_ioctl.h>
86
87MALLOC_DEFINE(M_AUTOFS, "autofs", "Automounter filesystem");
88
89uma_zone_t autofs_request_zone;
90uma_zone_t autofs_node_zone;
91
92static int	autofs_open(struct cdev *dev, int flags, int fmt,
93		    struct thread *td);
94static int	autofs_close(struct cdev *dev, int flag, int fmt,
95		    struct thread *td);
96static int	autofs_ioctl(struct cdev *dev, u_long cmd, caddr_t arg,
97		    int mode, struct thread *td);
98
99static struct cdevsw autofs_cdevsw = {
100     .d_version = D_VERSION,
101     .d_open   = autofs_open,
102     .d_close   = autofs_close,
103     .d_ioctl   = autofs_ioctl,
104     .d_name    = "autofs",
105};
106
107/*
108 * List of signals that can interrupt an autofs trigger.  Might be a good
109 * idea to keep it synchronised with list in sys/fs/nfs/nfs_commonkrpc.c.
110 */
111int autofs_sig_set[] = {
112	SIGINT,
113	SIGTERM,
114	SIGHUP,
115	SIGKILL,
116	SIGQUIT
117};
118
119struct autofs_softc	*autofs_softc;
120
121SYSCTL_NODE(_vfs, OID_AUTO, autofs, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
122    "Automounter filesystem");
123int autofs_debug = 1;
124TUNABLE_INT("vfs.autofs.debug", &autofs_debug);
125SYSCTL_INT(_vfs_autofs, OID_AUTO, debug, CTLFLAG_RWTUN,
126    &autofs_debug, 1, "Enable debug messages");
127int autofs_mount_on_stat = 0;
128TUNABLE_INT("vfs.autofs.mount_on_stat", &autofs_mount_on_stat);
129SYSCTL_INT(_vfs_autofs, OID_AUTO, mount_on_stat, CTLFLAG_RWTUN,
130    &autofs_mount_on_stat, 0, "Trigger mount on stat(2) on mountpoint");
131int autofs_timeout = 30;
132TUNABLE_INT("vfs.autofs.timeout", &autofs_timeout);
133SYSCTL_INT(_vfs_autofs, OID_AUTO, timeout, CTLFLAG_RWTUN,
134    &autofs_timeout, 30, "Number of seconds to wait for automountd(8)");
135int autofs_cache = 600;
136TUNABLE_INT("vfs.autofs.cache", &autofs_cache);
137SYSCTL_INT(_vfs_autofs, OID_AUTO, cache, CTLFLAG_RWTUN,
138    &autofs_cache, 600, "Number of seconds to wait before reinvoking "
139    "automountd(8) for any given file or directory");
140int autofs_retry_attempts = 3;
141TUNABLE_INT("vfs.autofs.retry_attempts", &autofs_retry_attempts);
142SYSCTL_INT(_vfs_autofs, OID_AUTO, retry_attempts, CTLFLAG_RWTUN,
143    &autofs_retry_attempts, 3, "Number of attempts before failing mount");
144int autofs_retry_delay = 1;
145TUNABLE_INT("vfs.autofs.retry_delay", &autofs_retry_delay);
146SYSCTL_INT(_vfs_autofs, OID_AUTO, retry_delay, CTLFLAG_RWTUN,
147    &autofs_retry_delay, 1, "Number of seconds before retrying");
148int autofs_interruptible = 1;
149TUNABLE_INT("vfs.autofs.interruptible", &autofs_interruptible);
150SYSCTL_INT(_vfs_autofs, OID_AUTO, interruptible, CTLFLAG_RWTUN,
151    &autofs_interruptible, 1, "Allow requests to be interrupted by signal");
152
153static int
154autofs_node_cmp(const struct autofs_node *a, const struct autofs_node *b)
155{
156
157	return (strcmp(a->an_name, b->an_name));
158}
159
160RB_GENERATE(autofs_node_tree, autofs_node, an_link, autofs_node_cmp);
161
162int
163autofs_init(struct vfsconf *vfsp)
164{
165	int error;
166
167	KASSERT(autofs_softc == NULL,
168	    ("softc %p, should be NULL", autofs_softc));
169
170	autofs_softc = malloc(sizeof(*autofs_softc), M_AUTOFS,
171	    M_WAITOK | M_ZERO);
172
173	autofs_request_zone = uma_zcreate("autofs_request",
174	    sizeof(struct autofs_request), NULL, NULL, NULL, NULL,
175	    UMA_ALIGN_PTR, 0);
176	autofs_node_zone = uma_zcreate("autofs_node",
177	    sizeof(struct autofs_node), NULL, NULL, NULL, NULL,
178	    UMA_ALIGN_PTR, 0);
179
180	TAILQ_INIT(&autofs_softc->sc_requests);
181	cv_init(&autofs_softc->sc_cv, "autofscv");
182	sx_init(&autofs_softc->sc_lock, "autofslk");
183
184	error = make_dev_p(MAKEDEV_CHECKNAME, &autofs_softc->sc_cdev,
185	    &autofs_cdevsw, NULL, UID_ROOT, GID_WHEEL, 0600, "autofs");
186	if (error != 0) {
187		AUTOFS_WARN("failed to create device node, error %d", error);
188		uma_zdestroy(autofs_request_zone);
189		uma_zdestroy(autofs_node_zone);
190		free(autofs_softc, M_AUTOFS);
191
192		return (error);
193	}
194	autofs_softc->sc_cdev->si_drv1 = autofs_softc;
195
196	return (0);
197}
198
199int
200autofs_uninit(struct vfsconf *vfsp)
201{
202
203	sx_xlock(&autofs_softc->sc_lock);
204	if (autofs_softc->sc_dev_opened) {
205		sx_xunlock(&autofs_softc->sc_lock);
206		return (EBUSY);
207	}
208	if (autofs_softc->sc_cdev != NULL)
209		destroy_dev(autofs_softc->sc_cdev);
210
211	uma_zdestroy(autofs_request_zone);
212	uma_zdestroy(autofs_node_zone);
213
214	sx_xunlock(&autofs_softc->sc_lock);
215	/*
216	 * XXX: Race with open?
217	 */
218	free(autofs_softc, M_AUTOFS);
219
220	return (0);
221}
222
223bool
224autofs_ignore_thread(const struct thread *td)
225{
226	struct proc *p;
227
228	p = td->td_proc;
229
230	if (autofs_softc->sc_dev_opened == false)
231		return (false);
232
233	PROC_LOCK(p);
234	if (p->p_session->s_sid == autofs_softc->sc_dev_sid) {
235		PROC_UNLOCK(p);
236		return (true);
237	}
238	PROC_UNLOCK(p);
239
240	return (false);
241}
242
243static char *
244autofs_path(struct autofs_node *anp)
245{
246	struct autofs_mount *amp;
247	char *path, *tmp;
248
249	amp = anp->an_mount;
250
251	path = strdup("", M_AUTOFS);
252	for (; anp->an_parent != NULL; anp = anp->an_parent) {
253		tmp = malloc(strlen(anp->an_name) + strlen(path) + 2,
254		    M_AUTOFS, M_WAITOK);
255		strcpy(tmp, anp->an_name);
256		strcat(tmp, "/");
257		strcat(tmp, path);
258		free(path, M_AUTOFS);
259		path = tmp;
260	}
261
262	tmp = malloc(strlen(amp->am_mountpoint) + strlen(path) + 2,
263	    M_AUTOFS, M_WAITOK);
264	strcpy(tmp, amp->am_mountpoint);
265	strcat(tmp, "/");
266	strcat(tmp, path);
267	free(path, M_AUTOFS);
268	path = tmp;
269
270	return (path);
271}
272
273static void
274autofs_task(void *context, int pending)
275{
276	struct autofs_request *ar;
277
278	ar = context;
279
280	sx_xlock(&autofs_softc->sc_lock);
281	AUTOFS_WARN("request %d for %s timed out after %d seconds",
282	    ar->ar_id, ar->ar_path, autofs_timeout);
283	/*
284	 * XXX: EIO perhaps?
285	 */
286	ar->ar_error = ETIMEDOUT;
287	ar->ar_wildcards = true;
288	ar->ar_done = true;
289	ar->ar_in_progress = false;
290	cv_broadcast(&autofs_softc->sc_cv);
291	sx_xunlock(&autofs_softc->sc_lock);
292}
293
294bool
295autofs_cached(struct autofs_node *anp, const char *component, int componentlen)
296{
297	int error;
298	struct autofs_mount *amp;
299
300	amp = anp->an_mount;
301
302	AUTOFS_ASSERT_UNLOCKED(amp);
303
304	/*
305	 * For root node we need to request automountd(8) assistance even
306	 * if the node is marked as cached, but the requested top-level
307	 * directory does not exist.  This is necessary for wildcard indirect
308	 * map keys to work.  We don't do this if we know that there are
309	 * no wildcards.
310	 */
311	if (anp->an_parent == NULL && componentlen != 0 && anp->an_wildcards) {
312		AUTOFS_SLOCK(amp);
313		error = autofs_node_find(anp, component, componentlen, NULL);
314		AUTOFS_SUNLOCK(amp);
315		if (error != 0)
316			return (false);
317	}
318
319	return (anp->an_cached);
320}
321
322static void
323autofs_cache_callout(void *context)
324{
325	struct autofs_node *anp;
326
327	anp = context;
328	anp->an_cached = false;
329}
330
331void
332autofs_flush(struct autofs_mount *amp)
333{
334
335	/*
336	 * XXX: This will do for now, but ideally we should iterate
337	 * 	over all the nodes.
338	 */
339	amp->am_root->an_cached = false;
340	AUTOFS_DEBUG("%s flushed", amp->am_mountpoint);
341}
342
343/*
344 * The set/restore sigmask functions are used to (temporarily) overwrite
345 * the thread td_sigmask during triggering.
346 */
347static void
348autofs_set_sigmask(sigset_t *oldset)
349{
350	sigset_t newset;
351	int i;
352
353	SIGFILLSET(newset);
354	/* Remove the autofs set of signals from newset */
355	PROC_LOCK(curproc);
356	mtx_lock(&curproc->p_sigacts->ps_mtx);
357	for (i = 0 ; i < nitems(autofs_sig_set); i++) {
358		/*
359		 * But make sure we leave the ones already masked
360		 * by the process, i.e. remove the signal from the
361		 * temporary signalmask only if it wasn't already
362		 * in p_sigmask.
363		 */
364		if (!SIGISMEMBER(curthread->td_sigmask, autofs_sig_set[i]) &&
365		    !SIGISMEMBER(curproc->p_sigacts->ps_sigignore,
366		    autofs_sig_set[i])) {
367			SIGDELSET(newset, autofs_sig_set[i]);
368		}
369	}
370	mtx_unlock(&curproc->p_sigacts->ps_mtx);
371	kern_sigprocmask(curthread, SIG_SETMASK, &newset, oldset,
372	    SIGPROCMASK_PROC_LOCKED);
373	PROC_UNLOCK(curproc);
374}
375
376static void
377autofs_restore_sigmask(sigset_t *set)
378{
379
380	kern_sigprocmask(curthread, SIG_SETMASK, set, NULL, 0);
381}
382
383static int
384autofs_trigger_one(struct autofs_node *anp,
385    const char *component, int componentlen)
386{
387	sigset_t oldset;
388	struct autofs_mount *amp;
389	struct autofs_node *firstanp;
390	struct autofs_request *ar;
391	char *key, *path;
392	int error = 0, request_error, last;
393	bool wildcards;
394
395	amp = anp->an_mount;
396
397	sx_assert(&autofs_softc->sc_lock, SA_XLOCKED);
398
399	if (anp->an_parent == NULL) {
400		key = strndup(component, componentlen, M_AUTOFS);
401	} else {
402		for (firstanp = anp; firstanp->an_parent->an_parent != NULL;
403		    firstanp = firstanp->an_parent)
404			continue;
405		key = strdup(firstanp->an_name, M_AUTOFS);
406	}
407
408	path = autofs_path(anp);
409
410	TAILQ_FOREACH(ar, &autofs_softc->sc_requests, ar_next) {
411		if (strcmp(ar->ar_path, path) != 0)
412			continue;
413		if (strcmp(ar->ar_key, key) != 0)
414			continue;
415
416		KASSERT(strcmp(ar->ar_from, amp->am_from) == 0,
417		    ("from changed; %s != %s", ar->ar_from, amp->am_from));
418		KASSERT(strcmp(ar->ar_prefix, amp->am_prefix) == 0,
419		    ("prefix changed; %s != %s",
420		     ar->ar_prefix, amp->am_prefix));
421		KASSERT(strcmp(ar->ar_options, amp->am_options) == 0,
422		    ("options changed; %s != %s",
423		     ar->ar_options, amp->am_options));
424
425		break;
426	}
427
428	if (ar != NULL) {
429		refcount_acquire(&ar->ar_refcount);
430	} else {
431		ar = uma_zalloc(autofs_request_zone, M_WAITOK | M_ZERO);
432		ar->ar_mount = amp;
433
434		ar->ar_id =
435		    atomic_fetchadd_int(&autofs_softc->sc_last_request_id, 1);
436		strlcpy(ar->ar_from, amp->am_from, sizeof(ar->ar_from));
437		strlcpy(ar->ar_path, path, sizeof(ar->ar_path));
438		strlcpy(ar->ar_prefix, amp->am_prefix, sizeof(ar->ar_prefix));
439		strlcpy(ar->ar_key, key, sizeof(ar->ar_key));
440		strlcpy(ar->ar_options,
441		    amp->am_options, sizeof(ar->ar_options));
442
443		TIMEOUT_TASK_INIT(taskqueue_thread, &ar->ar_task, 0,
444		    autofs_task, ar);
445		taskqueue_enqueue_timeout(taskqueue_thread, &ar->ar_task,
446		    autofs_timeout * hz);
447		refcount_init(&ar->ar_refcount, 1);
448		TAILQ_INSERT_TAIL(&autofs_softc->sc_requests, ar, ar_next);
449	}
450
451	cv_broadcast(&autofs_softc->sc_cv);
452	while (ar->ar_done == false) {
453		if (autofs_interruptible != 0) {
454			autofs_set_sigmask(&oldset);
455			error = cv_wait_sig(&autofs_softc->sc_cv,
456			    &autofs_softc->sc_lock);
457			autofs_restore_sigmask(&oldset);
458			if (error != 0) {
459				AUTOFS_WARN("cv_wait_sig for %s failed "
460				    "with error %d", ar->ar_path, error);
461				break;
462			}
463		} else {
464			cv_wait(&autofs_softc->sc_cv, &autofs_softc->sc_lock);
465		}
466	}
467
468	request_error = ar->ar_error;
469	if (request_error != 0) {
470		AUTOFS_WARN("request for %s completed with error %d, "
471		    "pid %d (%s)", ar->ar_path, request_error,
472		    curproc->p_pid, curproc->p_comm);
473	}
474
475	wildcards = ar->ar_wildcards;
476
477	last = refcount_release(&ar->ar_refcount);
478	if (last) {
479		TAILQ_REMOVE(&autofs_softc->sc_requests, ar, ar_next);
480		/*
481		 * Unlock the sc_lock, so that autofs_task() can complete.
482		 */
483		sx_xunlock(&autofs_softc->sc_lock);
484		taskqueue_cancel_timeout(taskqueue_thread, &ar->ar_task, NULL);
485		taskqueue_drain_timeout(taskqueue_thread, &ar->ar_task);
486		uma_zfree(autofs_request_zone, ar);
487		sx_xlock(&autofs_softc->sc_lock);
488	}
489
490	/*
491	 * Note that we do not do negative caching on purpose.  This
492	 * way the user can retry access at any time, e.g. after fixing
493	 * the failure reason, without waiting for cache timer to expire.
494	 */
495	if (error == 0 && request_error == 0 && autofs_cache > 0) {
496		anp->an_cached = true;
497		anp->an_wildcards = wildcards;
498		callout_reset(&anp->an_callout, autofs_cache * hz,
499		    autofs_cache_callout, anp);
500	}
501
502	free(key, M_AUTOFS);
503	free(path, M_AUTOFS);
504
505	if (error != 0)
506		return (error);
507	return (request_error);
508}
509
510/*
511 * Send request to automountd(8) and wait for completion.
512 */
513int
514autofs_trigger(struct autofs_node *anp,
515    const char *component, int componentlen)
516{
517	int error;
518
519	for (;;) {
520		error = autofs_trigger_one(anp, component, componentlen);
521		if (error == 0) {
522			anp->an_retries = 0;
523			return (0);
524		}
525		if (error == EINTR || error == ERESTART) {
526			AUTOFS_DEBUG("trigger interrupted by signal, "
527			    "not retrying");
528			anp->an_retries = 0;
529			return (error);
530		}
531		anp->an_retries++;
532		if (anp->an_retries >= autofs_retry_attempts) {
533			AUTOFS_DEBUG("trigger failed %d times; returning "
534			    "error %d", anp->an_retries, error);
535			anp->an_retries = 0;
536			return (error);
537		}
538		AUTOFS_DEBUG("trigger failed with error %d; will retry in "
539		    "%d seconds, %d attempts left", error, autofs_retry_delay,
540		    autofs_retry_attempts - anp->an_retries);
541		sx_xunlock(&autofs_softc->sc_lock);
542		pause("autofs_retry", autofs_retry_delay * hz);
543		sx_xlock(&autofs_softc->sc_lock);
544	}
545}
546
547static int
548autofs_ioctl_request(struct autofs_daemon_request *adr)
549{
550	struct autofs_request *ar;
551	int error;
552
553	sx_xlock(&autofs_softc->sc_lock);
554	for (;;) {
555		TAILQ_FOREACH(ar, &autofs_softc->sc_requests, ar_next) {
556			if (ar->ar_done)
557				continue;
558			if (ar->ar_in_progress)
559				continue;
560
561			break;
562		}
563
564		if (ar != NULL)
565			break;
566
567		error = cv_wait_sig(&autofs_softc->sc_cv,
568		    &autofs_softc->sc_lock);
569		if (error != 0) {
570			sx_xunlock(&autofs_softc->sc_lock);
571			return (error);
572		}
573	}
574
575	ar->ar_in_progress = true;
576	sx_xunlock(&autofs_softc->sc_lock);
577
578	adr->adr_id = ar->ar_id;
579	strlcpy(adr->adr_from, ar->ar_from, sizeof(adr->adr_from));
580	strlcpy(adr->adr_path, ar->ar_path, sizeof(adr->adr_path));
581	strlcpy(adr->adr_prefix, ar->ar_prefix, sizeof(adr->adr_prefix));
582	strlcpy(adr->adr_key, ar->ar_key, sizeof(adr->adr_key));
583	strlcpy(adr->adr_options, ar->ar_options, sizeof(adr->adr_options));
584
585	PROC_LOCK(curproc);
586	autofs_softc->sc_dev_sid = curproc->p_session->s_sid;
587	PROC_UNLOCK(curproc);
588
589	return (0);
590}
591
592static int
593autofs_ioctl_done_101(struct autofs_daemon_done_101 *add)
594{
595	struct autofs_request *ar;
596
597	sx_xlock(&autofs_softc->sc_lock);
598	TAILQ_FOREACH(ar, &autofs_softc->sc_requests, ar_next) {
599		if (ar->ar_id == add->add_id)
600			break;
601	}
602
603	if (ar == NULL) {
604		sx_xunlock(&autofs_softc->sc_lock);
605		AUTOFS_DEBUG("id %d not found", add->add_id);
606		return (ESRCH);
607	}
608
609	ar->ar_error = add->add_error;
610	ar->ar_wildcards = true;
611	ar->ar_done = true;
612	ar->ar_in_progress = false;
613	cv_broadcast(&autofs_softc->sc_cv);
614
615	sx_xunlock(&autofs_softc->sc_lock);
616
617	return (0);
618}
619
620static int
621autofs_ioctl_done(struct autofs_daemon_done *add)
622{
623	struct autofs_request *ar;
624
625	sx_xlock(&autofs_softc->sc_lock);
626	TAILQ_FOREACH(ar, &autofs_softc->sc_requests, ar_next) {
627		if (ar->ar_id == add->add_id)
628			break;
629	}
630
631	if (ar == NULL) {
632		sx_xunlock(&autofs_softc->sc_lock);
633		AUTOFS_DEBUG("id %d not found", add->add_id);
634		return (ESRCH);
635	}
636
637	ar->ar_error = add->add_error;
638	ar->ar_wildcards = add->add_wildcards;
639	ar->ar_done = true;
640	ar->ar_in_progress = false;
641	cv_broadcast(&autofs_softc->sc_cv);
642
643	sx_xunlock(&autofs_softc->sc_lock);
644
645	return (0);
646}
647
648static int
649autofs_open(struct cdev *dev, int flags, int fmt, struct thread *td)
650{
651
652	sx_xlock(&autofs_softc->sc_lock);
653	/*
654	 * We must never block automountd(8) and its descendants, and we use
655	 * session ID to determine that: we store session id of the process
656	 * that opened the device, and then compare it with session ids
657	 * of triggering processes.  This means running a second automountd(8)
658	 * instance would break the previous one.  The check below prevents
659	 * it from happening.
660	 */
661	if (autofs_softc->sc_dev_opened) {
662		sx_xunlock(&autofs_softc->sc_lock);
663		return (EBUSY);
664	}
665
666	autofs_softc->sc_dev_opened = true;
667	sx_xunlock(&autofs_softc->sc_lock);
668
669	return (0);
670}
671
672static int
673autofs_close(struct cdev *dev, int flag, int fmt, struct thread *td)
674{
675
676	sx_xlock(&autofs_softc->sc_lock);
677	KASSERT(autofs_softc->sc_dev_opened, ("not opened?"));
678	autofs_softc->sc_dev_opened = false;
679	sx_xunlock(&autofs_softc->sc_lock);
680
681	return (0);
682}
683
684static int
685autofs_ioctl(struct cdev *dev, u_long cmd, caddr_t arg, int mode,
686    struct thread *td)
687{
688
689	KASSERT(autofs_softc->sc_dev_opened, ("not opened?"));
690
691	switch (cmd) {
692	case AUTOFSREQUEST:
693		return (autofs_ioctl_request(
694		    (struct autofs_daemon_request *)arg));
695	case AUTOFSDONE101:
696		return (autofs_ioctl_done_101(
697		    (struct autofs_daemon_done_101 *)arg));
698	case AUTOFSDONE:
699		return (autofs_ioctl_done(
700		    (struct autofs_daemon_done *)arg));
701	default:
702		AUTOFS_DEBUG("invalid cmd %lx", cmd);
703		return (EINVAL);
704	}
705}
706