xref: /freebsd/sys/kern/uipc_mqueue.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
1 /*-
2  * Copyright (c) 2005 David Xu <davidxu@freebsd.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  */
27 
28 /*
29  * POSIX message queue implementation.
30  *
31  * 1) A mqueue filesystem can be mounted, each message queue appears
32  *    in mounted directory, user can change queue's permission and
33  *    ownership, or remove a queue. Manually creating a file in the
34  *    directory causes a message queue to be created in the kernel with
35  *    default message queue attributes applied and same name used, this
36  *    method is not advocated since mq_open syscall allows user to specify
37  *    different attributes. Also the file system can be mounted multiple
38  *    times at different mount points but shows same contents.
39  *
40  * 2) Standard POSIX message queue API. The syscalls do not use vfs layer,
41  *    but directly operate on internal data structure, this allows user to
42  *    use the IPC facility without having to mount mqueue file system.
43  */
44 
45 #include <sys/cdefs.h>
46 __FBSDID("$FreeBSD$");
47 
48 #include <sys/param.h>
49 #include <sys/kernel.h>
50 #include <sys/systm.h>
51 #include <sys/limits.h>
52 #include <sys/buf.h>
53 #include <sys/dirent.h>
54 #include <sys/event.h>
55 #include <sys/eventhandler.h>
56 #include <sys/fcntl.h>
57 #include <sys/file.h>
58 #include <sys/filedesc.h>
59 #include <sys/lock.h>
60 #include <sys/malloc.h>
61 #include <sys/module.h>
62 #include <sys/mount.h>
63 #include <sys/mqueue.h>
64 #include <sys/mutex.h>
65 #include <sys/namei.h>
66 #include <sys/posix4.h>
67 #include <sys/poll.h>
68 #include <sys/priv.h>
69 #include <sys/proc.h>
70 #include <sys/queue.h>
71 #include <sys/sysproto.h>
72 #include <sys/stat.h>
73 #include <sys/syscall.h>
74 #include <sys/syscallsubr.h>
75 #include <sys/sysent.h>
76 #include <sys/sx.h>
77 #include <sys/sysctl.h>
78 #include <sys/taskqueue.h>
79 #include <sys/unistd.h>
80 #include <sys/vnode.h>
81 #include <machine/atomic.h>
82 
83 /*
84  * Limits and constants
85  */
86 #define	MQFS_NAMELEN		NAME_MAX
87 #define MQFS_DELEN		(8 + MQFS_NAMELEN)
88 
89 /* node types */
90 typedef enum {
91 	mqfstype_none = 0,
92 	mqfstype_root,
93 	mqfstype_dir,
94 	mqfstype_this,
95 	mqfstype_parent,
96 	mqfstype_file,
97 	mqfstype_symlink,
98 } mqfs_type_t;
99 
100 struct mqfs_node;
101 
102 /*
103  * mqfs_info: describes a mqfs instance
104  */
105 struct mqfs_info {
106 	struct sx		mi_lock;
107 	struct mqfs_node	*mi_root;
108 	struct unrhdr		*mi_unrhdr;
109 };
110 
111 struct mqfs_vdata {
112 	LIST_ENTRY(mqfs_vdata)	mv_link;
113 	struct mqfs_node	*mv_node;
114 	struct vnode		*mv_vnode;
115 	struct task		mv_task;
116 };
117 
118 /*
119  * mqfs_node: describes a node (file or directory) within a mqfs
120  */
121 struct mqfs_node {
122 	char			mn_name[MQFS_NAMELEN+1];
123 	struct mqfs_info	*mn_info;
124 	struct mqfs_node	*mn_parent;
125 	LIST_HEAD(,mqfs_node)	mn_children;
126 	LIST_ENTRY(mqfs_node)	mn_sibling;
127 	LIST_HEAD(,mqfs_vdata)	mn_vnodes;
128 	int			mn_refcount;
129 	mqfs_type_t		mn_type;
130 	int			mn_deleted;
131 	u_int32_t		mn_fileno;
132 	void			*mn_data;
133 	struct timespec		mn_birth;
134 	struct timespec		mn_ctime;
135 	struct timespec		mn_atime;
136 	struct timespec		mn_mtime;
137 	uid_t			mn_uid;
138 	gid_t			mn_gid;
139 	int			mn_mode;
140 };
141 
142 #define	VTON(vp)	(((struct mqfs_vdata *)((vp)->v_data))->mv_node)
143 #define VTOMQ(vp) 	((struct mqueue *)(VTON(vp)->mn_data))
144 #define	VFSTOMQFS(m)	((struct mqfs_info *)((m)->mnt_data))
145 #define	FPTOMQ(fp)	((struct mqueue *)(((struct mqfs_node *) \
146 				(fp)->f_data)->mn_data))
147 
148 TAILQ_HEAD(msgq, mqueue_msg);
149 
150 struct mqueue;
151 
152 struct mqueue_notifier {
153 	LIST_ENTRY(mqueue_notifier)	nt_link;
154 	struct sigevent			nt_sigev;
155 	ksiginfo_t			nt_ksi;
156 	struct proc			*nt_proc;
157 };
158 
159 struct mqueue {
160 	struct mtx	mq_mutex;
161 	int		mq_flags;
162 	long		mq_maxmsg;
163 	long		mq_msgsize;
164 	long		mq_curmsgs;
165 	long		mq_totalbytes;
166 	struct msgq	mq_msgq;
167 	int		mq_receivers;
168 	int		mq_senders;
169 	struct selinfo	mq_rsel;
170 	struct selinfo	mq_wsel;
171 	struct mqueue_notifier	*mq_notifier;
172 };
173 
174 #define	MQ_RSEL		0x01
175 #define	MQ_WSEL		0x02
176 
177 struct mqueue_msg {
178 	TAILQ_ENTRY(mqueue_msg)	msg_link;
179 	unsigned int	msg_prio;
180 	unsigned int	msg_size;
181 	/* following real data... */
182 };
183 
184 SYSCTL_NODE(_kern, OID_AUTO, mqueue, CTLFLAG_RW, 0,
185 	"POSIX real time message queue");
186 
187 static int	default_maxmsg  = 10;
188 static int	default_msgsize = 1024;
189 
190 static int	maxmsg = 100;
191 SYSCTL_INT(_kern_mqueue, OID_AUTO, maxmsg, CTLFLAG_RW,
192     &maxmsg, 0, "Default maximum messages in queue");
193 static int	maxmsgsize = 16384;
194 SYSCTL_INT(_kern_mqueue, OID_AUTO, maxmsgsize, CTLFLAG_RW,
195     &maxmsgsize, 0, "Default maximum message size");
196 static int	maxmq = 100;
197 SYSCTL_INT(_kern_mqueue, OID_AUTO, maxmq, CTLFLAG_RW,
198     &maxmq, 0, "maximum message queues");
199 static int	curmq = 0;
200 SYSCTL_INT(_kern_mqueue, OID_AUTO, curmq, CTLFLAG_RW,
201     &curmq, 0, "current message queue number");
202 static int	unloadable = 0;
203 static MALLOC_DEFINE(M_MQUEUEDATA, "mqdata", "mqueue data");
204 
205 static eventhandler_tag exit_tag;
206 
207 /* Only one instance per-system */
208 static struct mqfs_info		mqfs_data;
209 static uma_zone_t		mqnode_zone;
210 static uma_zone_t		mqueue_zone;
211 static uma_zone_t		mvdata_zone;
212 static uma_zone_t		mqnoti_zone;
213 static struct vop_vector	mqfs_vnodeops;
214 static struct fileops		mqueueops;
215 
216 /*
217  * Directory structure construction and manipulation
218  */
219 #ifdef notyet
220 static struct mqfs_node	*mqfs_create_dir(struct mqfs_node *parent,
221 	const char *name, int namelen, struct ucred *cred, int mode);
222 static struct mqfs_node	*mqfs_create_link(struct mqfs_node *parent,
223 	const char *name, int namelen, struct ucred *cred, int mode);
224 #endif
225 
226 static struct mqfs_node	*mqfs_create_file(struct mqfs_node *parent,
227 	const char *name, int namelen, struct ucred *cred, int mode);
228 static int	mqfs_destroy(struct mqfs_node *mn);
229 static void	mqfs_fileno_alloc(struct mqfs_info *mi, struct mqfs_node *mn);
230 static void	mqfs_fileno_free(struct mqfs_info *mi, struct mqfs_node *mn);
231 static int	mqfs_allocv(struct mount *mp, struct vnode **vpp, struct mqfs_node *pn);
232 
233 /*
234  * Message queue construction and maniplation
235  */
236 static struct mqueue	*mqueue_alloc(const struct mq_attr *attr);
237 static void	mqueue_free(struct mqueue *mq);
238 static int	mqueue_send(struct mqueue *mq, const char *msg_ptr,
239 			size_t msg_len, unsigned msg_prio, int waitok,
240 			const struct timespec *abs_timeout);
241 static int	mqueue_receive(struct mqueue *mq, char *msg_ptr,
242 			size_t msg_len, unsigned *msg_prio, int waitok,
243 			const struct timespec *abs_timeout);
244 static int	_mqueue_send(struct mqueue *mq, struct mqueue_msg *msg,
245 			int timo);
246 static int	_mqueue_recv(struct mqueue *mq, struct mqueue_msg **msg,
247 			int timo);
248 static void	mqueue_send_notification(struct mqueue *mq);
249 static void	mqueue_fdclose(struct thread *td, int fd, struct file *fp);
250 static void	mq_proc_exit(void *arg, struct proc *p);
251 
252 /*
253  * kqueue filters
254  */
255 static void	filt_mqdetach(struct knote *kn);
256 static int	filt_mqread(struct knote *kn, long hint);
257 static int	filt_mqwrite(struct knote *kn, long hint);
258 
259 struct filterops mq_rfiltops =
260 	{ 1, NULL, filt_mqdetach, filt_mqread };
261 struct filterops mq_wfiltops =
262 	{ 1, NULL, filt_mqdetach, filt_mqwrite };
263 
264 /*
265  * Initialize fileno bitmap
266  */
267 static void
268 mqfs_fileno_init(struct mqfs_info *mi)
269 {
270 	struct unrhdr *up;
271 
272 	up = new_unrhdr(1, INT_MAX, NULL);
273 	mi->mi_unrhdr = up;
274 }
275 
276 /*
277  * Tear down fileno bitmap
278  */
279 static void
280 mqfs_fileno_uninit(struct mqfs_info *mi)
281 {
282 	struct unrhdr *up;
283 
284 	up = mi->mi_unrhdr;
285 	mi->mi_unrhdr = NULL;
286 	delete_unrhdr(up);
287 }
288 
289 /*
290  * Allocate a file number
291  */
292 static void
293 mqfs_fileno_alloc(struct mqfs_info *mi, struct mqfs_node *mn)
294 {
295 	/* make sure our parent has a file number */
296 	if (mn->mn_parent && !mn->mn_parent->mn_fileno)
297 		mqfs_fileno_alloc(mi, mn->mn_parent);
298 
299 	switch (mn->mn_type) {
300 	case mqfstype_root:
301 	case mqfstype_dir:
302 	case mqfstype_file:
303 	case mqfstype_symlink:
304 		mn->mn_fileno = alloc_unr(mi->mi_unrhdr);
305 		break;
306 	case mqfstype_this:
307 		KASSERT(mn->mn_parent != NULL,
308 		    ("mqfstype_this node has no parent"));
309 		mn->mn_fileno = mn->mn_parent->mn_fileno;
310 		break;
311 	case mqfstype_parent:
312 		KASSERT(mn->mn_parent != NULL,
313 		    ("mqfstype_parent node has no parent"));
314 		if (mn->mn_parent == mi->mi_root) {
315 			mn->mn_fileno = mn->mn_parent->mn_fileno;
316 			break;
317 		}
318 		KASSERT(mn->mn_parent->mn_parent != NULL,
319 		    ("mqfstype_parent node has no grandparent"));
320 		mn->mn_fileno = mn->mn_parent->mn_parent->mn_fileno;
321 		break;
322 	default:
323 		KASSERT(0,
324 		    ("mqfs_fileno_alloc() called for unknown type node: %d",
325 			mn->mn_type));
326 		break;
327 	}
328 }
329 
330 /*
331  * Release a file number
332  */
333 static void
334 mqfs_fileno_free(struct mqfs_info *mi, struct mqfs_node *mn)
335 {
336 	switch (mn->mn_type) {
337 	case mqfstype_root:
338 	case mqfstype_dir:
339 	case mqfstype_file:
340 	case mqfstype_symlink:
341 		free_unr(mi->mi_unrhdr, mn->mn_fileno);
342 		break;
343 	case mqfstype_this:
344 	case mqfstype_parent:
345 		/* ignore these, as they don't "own" their file number */
346 		break;
347 	default:
348 		KASSERT(0,
349 		    ("mqfs_fileno_free() called for unknown type node: %d",
350 			mn->mn_type));
351 		break;
352 	}
353 }
354 
355 static __inline struct mqfs_node *
356 mqnode_alloc(void)
357 {
358 	return uma_zalloc(mqnode_zone, M_WAITOK | M_ZERO);
359 }
360 
361 static __inline void
362 mqnode_free(struct mqfs_node *node)
363 {
364 	uma_zfree(mqnode_zone, node);
365 }
366 
367 static __inline void
368 mqnode_addref(struct mqfs_node *node)
369 {
370 	atomic_fetchadd_int(&node->mn_refcount, 1);
371 }
372 
373 static __inline void
374 mqnode_release(struct mqfs_node *node)
375 {
376 	int old, exp;
377 
378 	old = atomic_fetchadd_int(&node->mn_refcount, -1);
379 	if (node->mn_type == mqfstype_dir ||
380 	    node->mn_type == mqfstype_root)
381 		exp = 3; /* include . and .. */
382 	else
383 		exp = 1;
384 	if (old == exp)
385 		mqfs_destroy(node);
386 }
387 
388 /*
389  * Add a node to a directory
390  */
391 static int
392 mqfs_add_node(struct mqfs_node *parent, struct mqfs_node *node)
393 {
394 	KASSERT(parent != NULL, ("%s(): parent is NULL", __func__));
395 	KASSERT(parent->mn_info != NULL,
396 	    ("%s(): parent has no mn_info", __func__));
397 	KASSERT(parent->mn_type == mqfstype_dir ||
398 	    parent->mn_type == mqfstype_root,
399 	    ("%s(): parent is not a directory", __func__));
400 
401 	node->mn_info = parent->mn_info;
402 	node->mn_parent = parent;
403 	LIST_INIT(&node->mn_children);
404 	LIST_INIT(&node->mn_vnodes);
405 	LIST_INSERT_HEAD(&parent->mn_children, node, mn_sibling);
406 	mqnode_addref(parent);
407 	return (0);
408 }
409 
410 static struct mqfs_node *
411 mqfs_create_node(const char *name, int namelen, struct ucred *cred, int mode,
412 	int nodetype)
413 {
414 	struct mqfs_node *node;
415 
416 	node = mqnode_alloc();
417 	strncpy(node->mn_name, name, namelen);
418 	node->mn_type = nodetype;
419 	node->mn_refcount = 1;
420 	getnanotime(&node->mn_birth);
421 	node->mn_ctime = node->mn_atime = node->mn_mtime
422 		= node->mn_birth;
423 	node->mn_uid = cred->cr_uid;
424 	node->mn_gid = cred->cr_gid;
425 	node->mn_mode = mode;
426 	return (node);
427 }
428 
429 /*
430  * Create a file
431  */
432 static struct mqfs_node *
433 mqfs_create_file(struct mqfs_node *parent, const char *name, int namelen,
434 	struct ucred *cred, int mode)
435 {
436 	struct mqfs_node *node;
437 
438 	node = mqfs_create_node(name, namelen, cred, mode, mqfstype_file);
439 	if (mqfs_add_node(parent, node) != 0) {
440 		mqnode_free(node);
441 		return (NULL);
442 	}
443 	return (node);
444 }
445 
446 /*
447  * Add . and .. to a directory
448  */
449 static int
450 mqfs_fixup_dir(struct mqfs_node *parent)
451 {
452 	struct mqfs_node *dir;
453 
454 	dir = mqnode_alloc();
455 	dir->mn_name[0] = '.';
456 	dir->mn_type = mqfstype_this;
457 	dir->mn_refcount = 1;
458 	if (mqfs_add_node(parent, dir) != 0) {
459 		mqnode_free(dir);
460 		return (-1);
461 	}
462 
463 	dir = mqnode_alloc();
464 	dir->mn_name[0] = dir->mn_name[1] = '.';
465 	dir->mn_type = mqfstype_parent;
466 	dir->mn_refcount = 1;
467 
468 	if (mqfs_add_node(parent, dir) != 0) {
469 		mqnode_free(dir);
470 		return (-1);
471 	}
472 
473 	return (0);
474 }
475 
476 #ifdef notyet
477 
478 /*
479  * Create a directory
480  */
481 static struct mqfs_node *
482 mqfs_create_dir(struct mqfs_node *parent, const char *name, int namelen,
483 	struct ucred *cred, int mode)
484 {
485 	struct mqfs_node *node;
486 
487 	node = mqfs_create_node(name, namelen, cred, mode, mqfstype_dir);
488 	if (mqfs_add_node(parent, node) != 0) {
489 		mqnode_free(node);
490 		return (NULL);
491 	}
492 
493 	if (mqfs_fixup_dir(node) != 0) {
494 		mqfs_destroy(node);
495 		return (NULL);
496 	}
497 	return (node);
498 }
499 
500 /*
501  * Create a symlink
502  */
503 static struct mqfs_node *
504 mqfs_create_link(struct mqfs_node *parent, const char *name, int namelen,
505 	struct ucred *cred, int mode)
506 {
507 	struct mqfs_node *node;
508 
509 	node = mqfs_create_node(name, namelen, cred, mode, mqfstype_symlink);
510 	if (mqfs_add_node(parent, node) != 0) {
511 		mqnode_free(node);
512 		return (NULL);
513 	}
514 	return (node);
515 }
516 
517 #endif
518 
519 /*
520  * Destroy a node or a tree of nodes
521  */
522 static int
523 mqfs_destroy(struct mqfs_node *node)
524 {
525 	struct mqfs_node *parent;
526 
527 	KASSERT(node != NULL,
528 	    ("%s(): node is NULL", __func__));
529 	KASSERT(node->mn_info != NULL,
530 	    ("%s(): node has no mn_info", __func__));
531 
532 	/* destroy children */
533 	if (node->mn_type == mqfstype_dir || node->mn_type == mqfstype_root)
534 		while (! LIST_EMPTY(&node->mn_children))
535 			mqfs_destroy(LIST_FIRST(&node->mn_children));
536 
537 	/* unlink from parent */
538 	if ((parent = node->mn_parent) != NULL) {
539 		KASSERT(parent->mn_info == node->mn_info,
540 		    ("%s(): parent has different mn_info", __func__));
541 		LIST_REMOVE(node, mn_sibling);
542 	}
543 
544 	if (node->mn_fileno != 0)
545 		mqfs_fileno_free(node->mn_info, node);
546 	if (node->mn_data != NULL)
547 		mqueue_free(node->mn_data);
548 	mqnode_free(node);
549 	return (0);
550 }
551 
552 /*
553  * Mount a mqfs instance
554  */
555 static int
556 mqfs_mount(struct mount *mp, struct thread *td)
557 {
558 	struct statfs *sbp;
559 
560 	if (mp->mnt_flag & MNT_UPDATE)
561 		return (EOPNOTSUPP);
562 
563 	mp->mnt_data = &mqfs_data;
564 	MNT_ILOCK(mp);
565 	mp->mnt_flag |= MNT_LOCAL;
566 	mp->mnt_kern_flag |= MNTK_MPSAFE;
567 	MNT_IUNLOCK(mp);
568 	vfs_getnewfsid(mp);
569 
570 	sbp = &mp->mnt_stat;
571 	vfs_mountedfrom(mp, "mqueue");
572 	sbp->f_bsize = PAGE_SIZE;
573 	sbp->f_iosize = PAGE_SIZE;
574 	sbp->f_blocks = 1;
575 	sbp->f_bfree = 0;
576 	sbp->f_bavail = 0;
577 	sbp->f_files = 1;
578 	sbp->f_ffree = 0;
579 	return (0);
580 }
581 
582 /*
583  * Unmount a mqfs instance
584  */
585 static int
586 mqfs_unmount(struct mount *mp, int mntflags, struct thread *td)
587 {
588 	int error;
589 
590 	error = vflush(mp, 0, (mntflags & MNT_FORCE) ?  FORCECLOSE : 0, td);
591 	return (error);
592 }
593 
594 /*
595  * Return a root vnode
596  */
597 static int
598 mqfs_root(struct mount *mp, int flags, struct vnode **vpp, struct thread *td)
599 {
600 	struct mqfs_info *mqfs;
601 	int ret;
602 
603 	mqfs = VFSTOMQFS(mp);
604 	sx_xlock(&mqfs->mi_lock);
605 	ret = mqfs_allocv(mp, vpp, mqfs->mi_root);
606 	sx_xunlock(&mqfs->mi_lock);
607 	return (ret);
608 }
609 
610 /*
611  * Return filesystem stats
612  */
613 static int
614 mqfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td)
615 {
616 	/* XXX update statistics */
617 	return (0);
618 }
619 
620 /*
621  * Initialize a mqfs instance
622  */
623 static int
624 mqfs_init(struct vfsconf *vfc)
625 {
626 	struct mqfs_node *root;
627 	struct mqfs_info *mi;
628 
629 	mqnode_zone = uma_zcreate("mqnode", sizeof(struct mqfs_node),
630 		NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
631 	mqueue_zone = uma_zcreate("mqueue", sizeof(struct mqueue),
632 		NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
633 	mvdata_zone = uma_zcreate("mvdata",
634 		sizeof(struct mqfs_vdata), NULL, NULL, NULL,
635 		NULL, UMA_ALIGN_PTR, 0);
636 	mqnoti_zone = uma_zcreate("mqnotifier", sizeof(struct mqueue_notifier),
637 		NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
638 	mi = &mqfs_data;
639 	sx_init(&mi->mi_lock, "mqfs lock");
640 	/* set up the root diretory */
641 	root = mqfs_create_node("/", 1, curthread->td_ucred, 01777,
642 		mqfstype_root);
643 	root->mn_info = mi;
644 	LIST_INIT(&root->mn_children);
645 	LIST_INIT(&root->mn_vnodes);
646 	mi->mi_root = root;
647 	mqfs_fileno_init(mi);
648 	mqfs_fileno_alloc(mi, root);
649 	mqfs_fixup_dir(root);
650 	exit_tag = EVENTHANDLER_REGISTER(process_exit, mq_proc_exit, NULL,
651 	    EVENTHANDLER_PRI_ANY);
652 	mq_fdclose = mqueue_fdclose;
653 	p31b_setcfg(CTL_P1003_1B_MESSAGE_PASSING, _POSIX_MESSAGE_PASSING);
654 	return (0);
655 }
656 
657 /*
658  * Destroy a mqfs instance
659  */
660 static int
661 mqfs_uninit(struct vfsconf *vfc)
662 {
663 	struct mqfs_info *mi;
664 
665 	if (!unloadable)
666 		return (EOPNOTSUPP);
667 	EVENTHANDLER_DEREGISTER(process_exit, exit_tag);
668 	mi = &mqfs_data;
669 	mqfs_destroy(mi->mi_root);
670 	mi->mi_root = NULL;
671 	mqfs_fileno_uninit(mi);
672 	sx_destroy(&mi->mi_lock);
673 	uma_zdestroy(mqnode_zone);
674 	uma_zdestroy(mqueue_zone);
675 	uma_zdestroy(mvdata_zone);
676 	uma_zdestroy(mqnoti_zone);
677 	return (0);
678 }
679 
680 /*
681  * task routine
682  */
683 static void
684 do_recycle(void *context, int pending __unused)
685 {
686 	struct vnode *vp = (struct vnode *)context;
687 
688 	vrecycle(vp, curthread);
689 	vdrop(vp);
690 }
691 
692 /*
693  * Allocate a vnode
694  */
695 static int
696 mqfs_allocv(struct mount *mp, struct vnode **vpp, struct mqfs_node *pn)
697 {
698 	struct mqfs_vdata *vd;
699 	int error;
700 
701 	LIST_FOREACH(vd, &pn->mn_vnodes, mv_link) {
702 		if (vd->mv_vnode->v_mount == mp)
703 			break;
704 	}
705 
706 	if (vd != NULL) {
707 		if (vget(vd->mv_vnode, 0, curthread) == 0) {
708 			*vpp = vd->mv_vnode;
709 			vn_lock(*vpp, LK_RETRY | LK_EXCLUSIVE);
710 			return (0);
711 		}
712 		/* XXX if this can happen, we're in trouble */
713 	}
714 
715 	error = getnewvnode("mqueue", mp, &mqfs_vnodeops, vpp);
716 	if (error)
717 		return (error);
718 	vn_lock(*vpp, LK_EXCLUSIVE | LK_RETRY);
719 	error = insmntque(*vpp, mp);
720 	if (error != 0) {
721 		*vpp = NULLVP;
722 		return (error);
723 	}
724 	vd = uma_zalloc(mvdata_zone, M_WAITOK);
725 	(*vpp)->v_data = vd;
726 	vd->mv_vnode = *vpp;
727 	vd->mv_node = pn;
728 	TASK_INIT(&vd->mv_task, 0, do_recycle, *vpp);
729 	LIST_INSERT_HEAD(&pn->mn_vnodes, vd, mv_link);
730 	mqnode_addref(pn);
731 	switch (pn->mn_type) {
732 	case mqfstype_root:
733 		(*vpp)->v_vflag = VV_ROOT;
734 		/* fall through */
735 	case mqfstype_dir:
736 	case mqfstype_this:
737 	case mqfstype_parent:
738 		(*vpp)->v_type = VDIR;
739 		break;
740 	case mqfstype_file:
741 		(*vpp)->v_type = VREG;
742 		break;
743 	case mqfstype_symlink:
744 		(*vpp)->v_type = VLNK;
745 		break;
746 	case mqfstype_none:
747 		KASSERT(0, ("mqfs_allocf called for null node\n"));
748 	default:
749 		panic("%s has unexpected type: %d", pn->mn_name, pn->mn_type);
750 	}
751 	return (0);
752 }
753 
754 /*
755  * Search a directory entry
756  */
757 static struct mqfs_node *
758 mqfs_search(struct mqfs_node *pd, const char *name, int len)
759 {
760 	struct mqfs_node *pn;
761 
762 	LIST_FOREACH(pn, &pd->mn_children, mn_sibling) {
763 		if (strncmp(pn->mn_name, name, len) == 0)
764 			return (pn);
765 	}
766 	return (NULL);
767 }
768 
769 /*
770  * Look up a file or directory.
771  */
772 static int
773 mqfs_lookupx(struct vop_cachedlookup_args *ap)
774 {
775 	struct componentname *cnp;
776 	struct vnode *dvp, **vpp;
777 	struct mqfs_node *pd;
778 	struct mqfs_node *pn;
779 	int nameiop, flags, error, namelen;
780 	char *pname;
781 	struct thread *td;
782 
783 	cnp = ap->a_cnp;
784 	vpp = ap->a_vpp;
785 	dvp = ap->a_dvp;
786 	pname = cnp->cn_nameptr;
787 	namelen = cnp->cn_namelen;
788 	td = cnp->cn_thread;
789 	flags = cnp->cn_flags;
790 	nameiop = cnp->cn_nameiop;
791 	pd = VTON(dvp);
792 	pn = NULL;
793 	*vpp = NULLVP;
794 
795 	if (dvp->v_type != VDIR)
796 		return (ENOTDIR);
797 
798 	error = VOP_ACCESS(dvp, VEXEC, cnp->cn_cred, cnp->cn_thread);
799 	if (error)
800 		return (error);
801 
802 	/* shortcut: check if the name is too long */
803 	if (cnp->cn_namelen >= MQFS_NAMELEN)
804 		return (ENOENT);
805 
806 	/* self */
807 	if (namelen == 1 && pname[0] == '.') {
808 		if ((flags & ISLASTCN) && nameiop != LOOKUP)
809 			return (EINVAL);
810 		pn = pd;
811 		*vpp = dvp;
812 		VREF(dvp);
813 		return (0);
814 	}
815 
816 	/* parent */
817 	if (cnp->cn_flags & ISDOTDOT) {
818 		if (dvp->v_vflag & VV_ROOT)
819 			return (EIO);
820 		if ((flags & ISLASTCN) && nameiop != LOOKUP)
821 			return (EINVAL);
822 		VOP_UNLOCK(dvp, 0);
823 		KASSERT(pd->mn_parent, ("non-root directory has no parent"));
824 		pn = pd->mn_parent;
825 		error = mqfs_allocv(dvp->v_mount, vpp, pn);
826 		vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
827 		return (error);
828 	}
829 
830 	/* named node */
831 	pn = mqfs_search(pd, pname, namelen);
832 
833 	/* found */
834 	if (pn != NULL) {
835 		/* DELETE */
836 		if (nameiop == DELETE && (flags & ISLASTCN)) {
837 			error = VOP_ACCESS(dvp, VWRITE, cnp->cn_cred, td);
838 			if (error)
839 				return (error);
840 			if (*vpp == dvp) {
841 				VREF(dvp);
842 				*vpp = dvp;
843 				return (0);
844 			}
845 		}
846 
847 		/* allocate vnode */
848 		error = mqfs_allocv(dvp->v_mount, vpp, pn);
849 		if (error == 0 && cnp->cn_flags & MAKEENTRY)
850 			cache_enter(dvp, *vpp, cnp);
851 		return (error);
852 	}
853 
854 	/* not found */
855 
856 	/* will create a new entry in the directory ? */
857 	if ((nameiop == CREATE || nameiop == RENAME) && (flags & LOCKPARENT)
858 	    && (flags & ISLASTCN)) {
859 		error = VOP_ACCESS(dvp, VWRITE, cnp->cn_cred, td);
860 		if (error)
861 			return (error);
862 		cnp->cn_flags |= SAVENAME;
863 		return (EJUSTRETURN);
864 	}
865 	return (ENOENT);
866 }
867 
868 #if 0
869 struct vop_lookup_args {
870 	struct vop_generic_args a_gen;
871 	struct vnode *a_dvp;
872 	struct vnode **a_vpp;
873 	struct componentname *a_cnp;
874 };
875 #endif
876 
877 /*
878  * vnode lookup operation
879  */
880 static int
881 mqfs_lookup(struct vop_cachedlookup_args *ap)
882 {
883 	struct mqfs_info *mqfs = VFSTOMQFS(ap->a_dvp->v_mount);
884 	int rc;
885 
886 	sx_xlock(&mqfs->mi_lock);
887 	rc = mqfs_lookupx(ap);
888 	sx_xunlock(&mqfs->mi_lock);
889 	return (rc);
890 }
891 
892 #if 0
893 struct vop_create_args {
894 	struct vnode *a_dvp;
895 	struct vnode **a_vpp;
896 	struct componentname *a_cnp;
897 	struct vattr *a_vap;
898 };
899 #endif
900 
901 /*
902  * vnode creation operation
903  */
904 static int
905 mqfs_create(struct vop_create_args *ap)
906 {
907 	struct mqfs_info *mqfs = VFSTOMQFS(ap->a_dvp->v_mount);
908 	struct componentname *cnp = ap->a_cnp;
909 	struct mqfs_node *pd;
910 	struct mqfs_node *pn;
911 	struct mqueue *mq;
912 	int error;
913 
914 	pd = VTON(ap->a_dvp);
915 	if (pd->mn_type != mqfstype_root && pd->mn_type != mqfstype_dir)
916 		return (ENOTDIR);
917 	mq = mqueue_alloc(NULL);
918 	if (mq == NULL)
919 		return (EAGAIN);
920 	sx_xlock(&mqfs->mi_lock);
921 #if 0
922 	/* named node */
923 	pn = mqfs_search(pd, cnp->cn_nameptr, cnp->cn_namelen);
924 	if (pn != NULL) {
925 		mqueue_free(mq);
926 		sx_xunlock(&mqfs->mi_lock);
927 		return (EEXIST);
928 	}
929 #else
930 	if ((cnp->cn_flags & HASBUF) == 0)
931 		panic("%s: no name", __func__);
932 #endif
933 	pn = mqfs_create_file(pd, cnp->cn_nameptr, cnp->cn_namelen,
934 		cnp->cn_cred, ap->a_vap->va_mode);
935 	if (pn == NULL)
936 		error = ENOSPC;
937 	else {
938 		error = mqfs_allocv(ap->a_dvp->v_mount, ap->a_vpp, pn);
939 		if (error)
940 			mqfs_destroy(pn);
941 		else
942 			pn->mn_data = mq;
943 	}
944 	sx_xunlock(&mqfs->mi_lock);
945 	if (error)
946 		mqueue_free(mq);
947 	return (error);
948 }
949 
950 /*
951  * Remove an entry
952  */
953 static
954 int do_unlink(struct mqfs_node *pn, struct ucred *ucred)
955 {
956 	struct mqfs_node *parent;
957 	struct mqfs_vdata *vd;
958 	int error = 0;
959 
960 	sx_assert(&pn->mn_info->mi_lock, SX_LOCKED);
961 
962 	if (ucred->cr_uid != pn->mn_uid &&
963 	    (error = priv_check_cred(ucred, PRIV_MQ_ADMIN, 0)) != 0)
964 		error = EACCES;
965 	else if (!pn->mn_deleted) {
966 		parent = pn->mn_parent;
967 		pn->mn_parent = NULL;
968 		pn->mn_deleted = 1;
969 		LIST_REMOVE(pn, mn_sibling);
970 		LIST_FOREACH(vd, &pn->mn_vnodes, mv_link) {
971 			cache_purge(vd->mv_vnode);
972 			vhold(vd->mv_vnode);
973 			taskqueue_enqueue(taskqueue_thread, &vd->mv_task);
974 		}
975 		mqnode_release(pn);
976 		mqnode_release(parent);
977 	} else
978 		error = ENOENT;
979 	return (error);
980 }
981 
982 #if 0
983 struct vop_remove_args {
984 	struct vnode *a_dvp;
985 	struct vnode *a_vp;
986 	struct componentname *a_cnp;
987 };
988 #endif
989 
990 /*
991  * vnode removal operation
992  */
993 static int
994 mqfs_remove(struct vop_remove_args *ap)
995 {
996 	struct mqfs_info *mqfs = VFSTOMQFS(ap->a_dvp->v_mount);
997 	struct mqfs_node *pn;
998 	int error;
999 
1000 	if (ap->a_vp->v_type == VDIR)
1001                 return (EPERM);
1002 	pn = VTON(ap->a_vp);
1003 	sx_xlock(&mqfs->mi_lock);
1004 	error = do_unlink(pn, ap->a_cnp->cn_cred);
1005 	sx_xunlock(&mqfs->mi_lock);
1006 	return (error);
1007 }
1008 
1009 #if 0
1010 struct vop_inactive_args {
1011 	struct vnode *a_vp;
1012 	struct thread *a_td;
1013 };
1014 #endif
1015 
1016 static int
1017 mqfs_inactive(struct vop_inactive_args *ap)
1018 {
1019 	struct mqfs_node *pn = VTON(ap->a_vp);
1020 
1021 	if (pn->mn_deleted)
1022 		vrecycle(ap->a_vp, ap->a_td);
1023 	return (0);
1024 }
1025 
1026 #if 0
1027 struct vop_reclaim_args {
1028 	struct vop_generic_args a_gen;
1029 	struct vnode *a_vp;
1030 	struct thread *a_td;
1031 };
1032 #endif
1033 
1034 static int
1035 mqfs_reclaim(struct vop_reclaim_args *ap)
1036 {
1037 	struct mqfs_info *mqfs = VFSTOMQFS(ap->a_vp->v_mount);
1038 	struct vnode *vp = ap->a_vp;
1039 	struct mqfs_node *pn;
1040 	struct mqfs_vdata *vd;
1041 
1042 	vd = vp->v_data;
1043 	pn = vd->mv_node;
1044 	sx_xlock(&mqfs->mi_lock);
1045 	vp->v_data = NULL;
1046 	LIST_REMOVE(vd, mv_link);
1047 	uma_zfree(mvdata_zone, vd);
1048 	mqnode_release(pn);
1049 	sx_xunlock(&mqfs->mi_lock);
1050 	return (0);
1051 }
1052 
1053 #if 0
1054 struct vop_open_args {
1055 	struct vop_generic_args a_gen;
1056 	struct vnode *a_vp;
1057 	int a_mode;
1058 	struct ucred *a_cred;
1059 	struct thread *a_td;
1060 	int a_fdidx;
1061 };
1062 #endif
1063 
1064 static int
1065 mqfs_open(struct vop_open_args *ap)
1066 {
1067 	return (0);
1068 }
1069 
1070 #if 0
1071 struct vop_close_args {
1072 	struct vop_generic_args a_gen;
1073 	struct vnode *a_vp;
1074 	int a_fflag;
1075 	struct ucred *a_cred;
1076 	struct thread *a_td;
1077 };
1078 #endif
1079 
1080 static int
1081 mqfs_close(struct vop_close_args *ap)
1082 {
1083 	return (0);
1084 }
1085 
1086 #if 0
1087 struct vop_access_args {
1088 	struct vop_generic_args a_gen;
1089 	struct vnode *a_vp;
1090 	int a_mode;
1091 	struct ucred *a_cred;
1092 	struct thread *a_td;
1093 };
1094 #endif
1095 
1096 /*
1097  * Verify permissions
1098  */
1099 static int
1100 mqfs_access(struct vop_access_args *ap)
1101 {
1102 	struct vnode *vp = ap->a_vp;
1103 	struct vattr vattr;
1104 	int error;
1105 
1106 	error = VOP_GETATTR(vp, &vattr, ap->a_cred, ap->a_td);
1107 	if (error)
1108 		return (error);
1109 	error = vaccess(vp->v_type, vattr.va_mode, vattr.va_uid,
1110 	    vattr.va_gid, ap->a_mode, ap->a_cred, NULL);
1111 	return (error);
1112 }
1113 
1114 #if 0
1115 struct vop_getattr_args {
1116 	struct vop_generic_args a_gen;
1117 	struct vnode *a_vp;
1118 	struct vattr *a_vap;
1119 	struct ucred *a_cred;
1120 	struct thread *a_td;
1121 };
1122 #endif
1123 
1124 /*
1125  * Get file attributes
1126  */
1127 static int
1128 mqfs_getattr(struct vop_getattr_args *ap)
1129 {
1130 	struct vnode *vp = ap->a_vp;
1131 	struct mqfs_node *pn = VTON(vp);
1132 	struct vattr *vap = ap->a_vap;
1133 	int error = 0;
1134 
1135 	VATTR_NULL(vap);
1136 	vap->va_type = vp->v_type;
1137 	vap->va_mode = pn->mn_mode;
1138 	vap->va_nlink = 1;
1139 	vap->va_uid = pn->mn_uid;
1140 	vap->va_gid = pn->mn_gid;
1141 	vap->va_fsid = vp->v_mount->mnt_stat.f_fsid.val[0];
1142 	vap->va_fileid = pn->mn_fileno;
1143 	vap->va_size = 0;
1144 	vap->va_blocksize = PAGE_SIZE;
1145 	vap->va_bytes = vap->va_size = 0;
1146 	vap->va_atime = pn->mn_atime;
1147 	vap->va_mtime = pn->mn_mtime;
1148 	vap->va_ctime = pn->mn_ctime;
1149 	vap->va_birthtime = pn->mn_birth;
1150 	vap->va_gen = 0;
1151 	vap->va_flags = 0;
1152 	vap->va_rdev = 0;
1153 	vap->va_bytes = 0;
1154 	vap->va_filerev = 0;
1155 	vap->va_vaflags = 0;
1156 	return (error);
1157 }
1158 
1159 #if 0
1160 struct vop_setattr_args {
1161 	struct vop_generic_args a_gen;
1162 	struct vnode *a_vp;
1163 	struct vattr *a_vap;
1164 	struct ucred *a_cred;
1165 	struct thread *a_td;
1166 };
1167 #endif
1168 /*
1169  * Set attributes
1170  */
1171 static int
1172 mqfs_setattr(struct vop_setattr_args *ap)
1173 {
1174 	struct mqfs_node *pn;
1175 	struct vattr *vap;
1176 	struct vnode *vp;
1177 	int c, error;
1178 	uid_t uid;
1179 	gid_t gid;
1180 
1181 	vap = ap->a_vap;
1182 	vp = ap->a_vp;
1183 	if ((vap->va_type != VNON) ||
1184 	    (vap->va_nlink != VNOVAL) ||
1185 	    (vap->va_fsid != VNOVAL) ||
1186 	    (vap->va_fileid != VNOVAL) ||
1187 	    (vap->va_blocksize != VNOVAL) ||
1188 	    (vap->va_flags != VNOVAL && vap->va_flags != 0) ||
1189 	    (vap->va_rdev != VNOVAL) ||
1190 	    ((int)vap->va_bytes != VNOVAL) ||
1191 	    (vap->va_gen != VNOVAL)) {
1192 		return (EINVAL);
1193 	}
1194 
1195 	pn = VTON(vp);
1196 
1197 	error = c = 0;
1198 	if (vap->va_uid == (uid_t)VNOVAL)
1199 		uid = pn->mn_uid;
1200 	else
1201 		uid = vap->va_uid;
1202 	if (vap->va_gid == (gid_t)VNOVAL)
1203 		gid = pn->mn_gid;
1204 	else
1205 		gid = vap->va_gid;
1206 
1207 	if (uid != pn->mn_uid || gid != pn->mn_gid) {
1208 		/*
1209 		 * To modify the ownership of a file, must possess VADMIN
1210 		 * for that file.
1211 		 */
1212 		if ((error = VOP_ACCESS(vp, VADMIN, ap->a_cred, ap->a_td)))
1213 			return (error);
1214 
1215 		/*
1216 		 * XXXRW: Why is there a privilege check here: shouldn't the
1217 		 * check in VOP_ACCESS() be enough?  Also, are the group bits
1218 		 * below definitely right?
1219 		 */
1220 		if (((ap->a_cred->cr_uid != pn->mn_uid) || uid != pn->mn_uid ||
1221 		    (gid != pn->mn_gid && !groupmember(gid, ap->a_cred))) &&
1222 		    (error = priv_check(ap->a_td, PRIV_MQ_ADMIN)) != 0)
1223 			return (error);
1224 		pn->mn_uid = uid;
1225 		pn->mn_gid = gid;
1226 		c = 1;
1227 	}
1228 
1229 	if (vap->va_mode != (mode_t)VNOVAL) {
1230 		if ((ap->a_cred->cr_uid != pn->mn_uid) &&
1231 		    (error = priv_check(ap->a_td, PRIV_MQ_ADMIN)))
1232 			return (error);
1233 		pn->mn_mode = vap->va_mode;
1234 		c = 1;
1235 	}
1236 
1237 	if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) {
1238 		/* See the comment in ufs_vnops::ufs_setattr(). */
1239 		if ((error = VOP_ACCESS(vp, VADMIN, ap->a_cred, ap->a_td)) &&
1240 		    ((vap->va_vaflags & VA_UTIMES_NULL) == 0 ||
1241 		    (error = VOP_ACCESS(vp, VWRITE, ap->a_cred, ap->a_td))))
1242 			return (error);
1243 		if (vap->va_atime.tv_sec != VNOVAL) {
1244 			pn->mn_atime = vap->va_atime;
1245 		}
1246 		if (vap->va_mtime.tv_sec != VNOVAL) {
1247 			pn->mn_mtime = vap->va_mtime;
1248 		}
1249 		c = 1;
1250 	}
1251 	if (c) {
1252 		vfs_timestamp(&pn->mn_ctime);
1253 	}
1254 	return (0);
1255 }
1256 
1257 #if 0
1258 struct vop_read_args {
1259 	struct vop_generic_args a_gen;
1260 	struct vnode *a_vp;
1261 	struct uio *a_uio;
1262 	int a_ioflag;
1263 	struct ucred *a_cred;
1264 };
1265 #endif
1266 
1267 /*
1268  * Read from a file
1269  */
1270 static int
1271 mqfs_read(struct vop_read_args *ap)
1272 {
1273 	char buf[80];
1274 	struct vnode *vp = ap->a_vp;
1275 	struct uio *uio = ap->a_uio;
1276 	struct mqfs_node *pn;
1277 	struct mqueue *mq;
1278 	int len, error;
1279 
1280 	if (vp->v_type != VREG)
1281 		return (EINVAL);
1282 
1283 	pn = VTON(vp);
1284 	mq = VTOMQ(vp);
1285 	snprintf(buf, sizeof(buf),
1286 		"QSIZE:%-10ld MAXMSG:%-10ld CURMSG:%-10ld MSGSIZE:%-10ld\n",
1287 		mq->mq_totalbytes,
1288 		mq->mq_maxmsg,
1289 		mq->mq_curmsgs,
1290 		mq->mq_msgsize);
1291 	buf[sizeof(buf)-1] = '\0';
1292 	len = strlen(buf);
1293 	error = uiomove_frombuf(buf, len, uio);
1294 	return (error);
1295 }
1296 
1297 #if 0
1298 struct vop_readdir_args {
1299 	struct vop_generic_args a_gen;
1300 	struct vnode *a_vp;
1301 	struct uio *a_uio;
1302 	struct ucred *a_cred;
1303 	int *a_eofflag;
1304 	int *a_ncookies;
1305 	u_long **a_cookies;
1306 };
1307 #endif
1308 
1309 /*
1310  * Return directory entries.
1311  */
1312 static int
1313 mqfs_readdir(struct vop_readdir_args *ap)
1314 {
1315 	struct vnode *vp;
1316 	struct mqfs_info *mi;
1317 	struct mqfs_node *pd;
1318 	struct mqfs_node *pn;
1319 	struct dirent entry;
1320 	struct uio *uio;
1321 	int *tmp_ncookies = NULL;
1322 	off_t offset;
1323 	int error, i;
1324 
1325 	vp = ap->a_vp;
1326 	mi = VFSTOMQFS(vp->v_mount);
1327 	pd = VTON(vp);
1328 	uio = ap->a_uio;
1329 
1330 	if (vp->v_type != VDIR)
1331 		return (ENOTDIR);
1332 
1333 	if (uio->uio_offset < 0)
1334 		return (EINVAL);
1335 
1336 	if (ap->a_ncookies != NULL) {
1337 		tmp_ncookies = ap->a_ncookies;
1338 		*ap->a_ncookies = 0;
1339 		ap->a_ncookies = NULL;
1340         }
1341 
1342 	error = 0;
1343 	offset = 0;
1344 
1345 	sx_xlock(&mi->mi_lock);
1346 
1347 	LIST_FOREACH(pn, &pd->mn_children, mn_sibling) {
1348 		entry.d_reclen = sizeof(entry);
1349 		if (!pn->mn_fileno)
1350 			mqfs_fileno_alloc(mi, pn);
1351 		entry.d_fileno = pn->mn_fileno;
1352 		for (i = 0; i < MQFS_NAMELEN - 1 && pn->mn_name[i] != '\0'; ++i)
1353 			entry.d_name[i] = pn->mn_name[i];
1354 		entry.d_name[i] = 0;
1355 		entry.d_namlen = i;
1356 		switch (pn->mn_type) {
1357 		case mqfstype_root:
1358 		case mqfstype_dir:
1359 		case mqfstype_this:
1360 		case mqfstype_parent:
1361 			entry.d_type = DT_DIR;
1362 			break;
1363 		case mqfstype_file:
1364 			entry.d_type = DT_REG;
1365 			break;
1366 		case mqfstype_symlink:
1367 			entry.d_type = DT_LNK;
1368 			break;
1369 		default:
1370 			panic("%s has unexpected node type: %d", pn->mn_name,
1371 				pn->mn_type);
1372 		}
1373 		if (entry.d_reclen > uio->uio_resid)
1374                         break;
1375 		if (offset >= uio->uio_offset) {
1376 			error = vfs_read_dirent(ap, &entry, offset);
1377                         if (error)
1378                                 break;
1379                 }
1380                 offset += entry.d_reclen;
1381 	}
1382 	sx_xunlock(&mi->mi_lock);
1383 
1384 	uio->uio_offset = offset;
1385 
1386 	if (tmp_ncookies != NULL)
1387 		ap->a_ncookies = tmp_ncookies;
1388 
1389 	return (error);
1390 }
1391 
1392 #ifdef notyet
1393 
1394 #if 0
1395 struct vop_mkdir_args {
1396 	struct vnode *a_dvp;
1397 	struvt vnode **a_vpp;
1398 	struvt componentname *a_cnp;
1399 	struct vattr *a_vap;
1400 };
1401 #endif
1402 
1403 /*
1404  * Create a directory.
1405  */
1406 static int
1407 mqfs_mkdir(struct vop_mkdir_args *ap)
1408 {
1409 	struct mqfs_info *mqfs = VFSTOMQFS(ap->a_dvp->v_mount);
1410 	struct componentname *cnp = ap->a_cnp;
1411 	struct mqfs_node *pd = VTON(ap->a_dvp);
1412 	struct mqfs_node *pn;
1413 	int error;
1414 
1415 	if (pd->mn_type != mqfstype_root && pd->mn_type != mqfstype_dir)
1416 		return (ENOTDIR);
1417 	sx_xlock(&mqfs->mi_lock);
1418 #if 0
1419 	/* named node */
1420 	pn = mqfs_search(pd, cnp->cn_nameptr, cnp->cn_namelen);
1421 	if (pn != NULL) {
1422 		sx_xunlock(&mqfs->mi_lock);
1423 		return (EEXIST);
1424 	}
1425 #else
1426 	if ((cnp->cn_flags & HASBUF) == 0)
1427 		panic("%s: no name", __func__);
1428 #endif
1429 	pn = mqfs_create_dir(pd, cnp->cn_nameptr, cnp->cn_namelen,
1430 		ap->a_vap->cn_cred, ap->a_vap->va_mode);
1431 	if (pn == NULL)
1432 		error = ENOSPC;
1433 	else
1434 		error = mqfs_allocv(ap->a_dvp->v_mount, ap->a_vpp, pn);
1435 	sx_xunlock(&mqfs->mi_lock);
1436 	return (error);
1437 }
1438 
1439 #if 0
1440 struct vop_rmdir_args {
1441 	struct vnode *a_dvp;
1442 	struct vnode *a_vp;
1443 	struct componentname *a_cnp;
1444 };
1445 #endif
1446 
1447 /*
1448  * Remove a directory.
1449  */
1450 static int
1451 mqfs_rmdir(struct vop_rmdir_args *ap)
1452 {
1453 	struct mqfs_info *mqfs = VFSTOMQFS(ap->a_dvp->v_mount);
1454 	struct mqfs_node *pn = VTON(ap->a_vp);
1455 	struct mqfs_node *pt;
1456 
1457 	if (pn->mn_type != mqfstype_dir)
1458 		return (ENOTDIR);
1459 
1460 	sx_xlock(&mqfs->mi_lock);
1461 	if (pn->mn_deleted) {
1462 		sx_xunlock(&mqfs->mi_lock);
1463 		return (ENOENT);
1464 	}
1465 
1466 	pt = LIST_FIRST(&pn->mn_children);
1467 	pt = LIST_NEXT(pt, mn_sibling);
1468 	pt = LIST_NEXT(pt, mn_sibling);
1469 	if (pt != NULL) {
1470 		sx_xunlock(&mqfs->mi_lock);
1471 		return (ENOTEMPTY);
1472 	}
1473 	pt = pn->mn_parent;
1474 	pn->mn_parent = NULL;
1475 	pn->mn_deleted = 1;
1476 	LIST_REMOVE(pn, mn_sibling);
1477 	mqnode_release(pn);
1478 	mqnode_release(pt);
1479 	sx_xunlock(&mqfs->mi_lock);
1480 	cache_purge(ap->a_vp);
1481 	return (0);
1482 }
1483 
1484 #endif /* notyet */
1485 
1486 /*
1487  * Allocate a message queue
1488  */
1489 static struct mqueue *
1490 mqueue_alloc(const struct mq_attr *attr)
1491 {
1492 	struct mqueue *mq;
1493 
1494 	if (curmq >= maxmq)
1495 		return (NULL);
1496 	mq = uma_zalloc(mqueue_zone, M_WAITOK | M_ZERO);
1497 	TAILQ_INIT(&mq->mq_msgq);
1498 	if (attr != NULL) {
1499 		mq->mq_maxmsg = attr->mq_maxmsg;
1500 		mq->mq_msgsize = attr->mq_msgsize;
1501 	} else {
1502 		mq->mq_maxmsg = default_maxmsg;
1503 		mq->mq_msgsize = default_msgsize;
1504 	}
1505 	mtx_init(&mq->mq_mutex, "mqueue", NULL, MTX_DEF);
1506 	knlist_init(&mq->mq_rsel.si_note, &mq->mq_mutex, NULL, NULL, NULL);
1507 	knlist_init(&mq->mq_wsel.si_note, &mq->mq_mutex, NULL, NULL, NULL);
1508 	atomic_add_int(&curmq, 1);
1509 	return (mq);
1510 }
1511 
1512 /*
1513  * Destroy a message queue
1514  */
1515 static void
1516 mqueue_free(struct mqueue *mq)
1517 {
1518 	struct mqueue_msg *msg;
1519 
1520 	while ((msg = TAILQ_FIRST(&mq->mq_msgq)) != NULL) {
1521 		TAILQ_REMOVE(&mq->mq_msgq, msg, msg_link);
1522 		FREE(msg, M_MQUEUEDATA);
1523 	}
1524 
1525 	mtx_destroy(&mq->mq_mutex);
1526 	knlist_destroy(&mq->mq_rsel.si_note);
1527 	knlist_destroy(&mq->mq_wsel.si_note);
1528 	uma_zfree(mqueue_zone, mq);
1529 	atomic_add_int(&curmq, -1);
1530 }
1531 
1532 /*
1533  * Load a message from user space
1534  */
1535 static struct mqueue_msg *
1536 mqueue_loadmsg(const char *msg_ptr, size_t msg_size, int msg_prio)
1537 {
1538 	struct mqueue_msg *msg;
1539 	size_t len;
1540 	int error;
1541 
1542 	len = sizeof(struct mqueue_msg) + msg_size;
1543 	MALLOC(msg, struct mqueue_msg *, len, M_MQUEUEDATA, M_WAITOK);
1544 	error = copyin(msg_ptr, ((char *)msg) + sizeof(struct mqueue_msg),
1545 	    msg_size);
1546 	if (error) {
1547 		FREE(msg, M_MQUEUEDATA);
1548 		msg = NULL;
1549 	} else {
1550 		msg->msg_size = msg_size;
1551 		msg->msg_prio = msg_prio;
1552 	}
1553 	return (msg);
1554 }
1555 
1556 /*
1557  * Save a message to user space
1558  */
1559 static int
1560 mqueue_savemsg(struct mqueue_msg *msg, char *msg_ptr, int *msg_prio)
1561 {
1562 	int error;
1563 
1564 	error = copyout(((char *)msg) + sizeof(*msg), msg_ptr,
1565 		msg->msg_size);
1566 	if (error == 0 && msg_prio != NULL)
1567 		error = copyout(&msg->msg_prio, msg_prio, sizeof(int));
1568 	return (error);
1569 }
1570 
1571 /*
1572  * Free a message's memory
1573  */
1574 static __inline void
1575 mqueue_freemsg(struct mqueue_msg *msg)
1576 {
1577 	FREE(msg, M_MQUEUEDATA);
1578 }
1579 
1580 /*
1581  * Send a message. if waitok is false, thread will not be
1582  * blocked if there is no data in queue, otherwise, absolute
1583  * time will be checked.
1584  */
1585 int
1586 mqueue_send(struct mqueue *mq, const char *msg_ptr,
1587 	size_t msg_len, unsigned msg_prio, int waitok,
1588 	const struct timespec *abs_timeout)
1589 {
1590 	struct mqueue_msg *msg;
1591 	struct timespec ets, ts, ts2;
1592 	struct timeval tv;
1593 	int error;
1594 
1595 	if (msg_prio >= MQ_PRIO_MAX)
1596 		return (EINVAL);
1597 	if (msg_len > mq->mq_msgsize)
1598 		return (EMSGSIZE);
1599 	msg = mqueue_loadmsg(msg_ptr, msg_len, msg_prio);
1600 	if (msg == NULL)
1601 		return (EFAULT);
1602 
1603 	/* O_NONBLOCK case */
1604 	if (!waitok) {
1605 		error = _mqueue_send(mq, msg, -1);
1606 		if (error)
1607 			goto bad;
1608 		return (0);
1609 	}
1610 
1611 	/* we allow a null timeout (wait forever) */
1612 	if (abs_timeout == NULL) {
1613 		error = _mqueue_send(mq, msg, 0);
1614 		if (error)
1615 			goto bad;
1616 		return (0);
1617 	}
1618 
1619 	/* send it before checking time */
1620 	error = _mqueue_send(mq, msg, -1);
1621 	if (error == 0)
1622 		return (0);
1623 
1624 	if (error != EAGAIN)
1625 		goto bad;
1626 
1627 	error = copyin(abs_timeout, &ets, sizeof(ets));
1628 	if (error != 0)
1629 		goto bad;
1630 	if (ets.tv_nsec >= 1000000000 || ets.tv_nsec < 0) {
1631 		error = EINVAL;
1632 		goto bad;
1633 	}
1634 	for (;;) {
1635 		ts2 = ets;
1636 		getnanotime(&ts);
1637 		timespecsub(&ts2, &ts);
1638 		if (ts2.tv_sec < 0 || (ts2.tv_sec == 0 && ts2.tv_nsec <= 0)) {
1639 			error = ETIMEDOUT;
1640 			break;
1641 		}
1642 		TIMESPEC_TO_TIMEVAL(&tv, &ts2);
1643 		error = _mqueue_send(mq, msg, tvtohz(&tv));
1644 		if (error != ETIMEDOUT)
1645 			break;
1646 	}
1647 	if (error == 0)
1648 		return (0);
1649 bad:
1650 	mqueue_freemsg(msg);
1651 	return (error);
1652 }
1653 
1654 /*
1655  * Common routine to send a message
1656  */
1657 static int
1658 _mqueue_send(struct mqueue *mq, struct mqueue_msg *msg, int timo)
1659 {
1660 	struct mqueue_msg *msg2;
1661 	int error = 0;
1662 
1663 	mtx_lock(&mq->mq_mutex);
1664 	while (mq->mq_curmsgs >= mq->mq_maxmsg && error == 0) {
1665 		if (timo < 0) {
1666 			mtx_unlock(&mq->mq_mutex);
1667 			return (EAGAIN);
1668 		}
1669 		mq->mq_senders++;
1670 		error = msleep(&mq->mq_senders, &mq->mq_mutex,
1671 			    PCATCH, "mqsend", timo);
1672 		mq->mq_senders--;
1673 		if (error == EAGAIN)
1674 			error = ETIMEDOUT;
1675 	}
1676 	if (mq->mq_curmsgs >= mq->mq_maxmsg) {
1677 		mtx_unlock(&mq->mq_mutex);
1678 		return (error);
1679 	}
1680 	error = 0;
1681 	if (TAILQ_EMPTY(&mq->mq_msgq)) {
1682 		TAILQ_INSERT_HEAD(&mq->mq_msgq, msg, msg_link);
1683 	} else {
1684 		if (msg->msg_prio <= TAILQ_LAST(&mq->mq_msgq, msgq)->msg_prio) {
1685 			TAILQ_INSERT_TAIL(&mq->mq_msgq, msg, msg_link);
1686 		} else {
1687 			TAILQ_FOREACH(msg2, &mq->mq_msgq, msg_link) {
1688 				if (msg2->msg_prio < msg->msg_prio)
1689 					break;
1690 			}
1691 			TAILQ_INSERT_BEFORE(msg2, msg, msg_link);
1692 		}
1693 	}
1694 	mq->mq_curmsgs++;
1695 	mq->mq_totalbytes += msg->msg_size;
1696 	if (mq->mq_receivers)
1697 		wakeup_one(&mq->mq_receivers);
1698 	else if (mq->mq_notifier != NULL)
1699 		mqueue_send_notification(mq);
1700 	if (mq->mq_flags & MQ_RSEL) {
1701 		mq->mq_flags &= ~MQ_RSEL;
1702 		selwakeup(&mq->mq_rsel);
1703 	}
1704 	KNOTE_LOCKED(&mq->mq_rsel.si_note, 0);
1705 	mtx_unlock(&mq->mq_mutex);
1706 	return (0);
1707 }
1708 
1709 /*
1710  * Send realtime a signal to process which registered itself
1711  * successfully by mq_notify.
1712  */
1713 static void
1714 mqueue_send_notification(struct mqueue *mq)
1715 {
1716 	struct mqueue_notifier *nt;
1717 	struct proc *p;
1718 
1719 	mtx_assert(&mq->mq_mutex, MA_OWNED);
1720 	nt = mq->mq_notifier;
1721 	if (nt->nt_sigev.sigev_notify != SIGEV_NONE) {
1722 		p = nt->nt_proc;
1723 		PROC_LOCK(p);
1724 		if (!KSI_ONQ(&nt->nt_ksi))
1725 			psignal_event(p, &nt->nt_sigev, &nt->nt_ksi);
1726 		PROC_UNLOCK(p);
1727 	}
1728 	mq->mq_notifier = NULL;
1729 }
1730 
1731 /*
1732  * Get a message. if waitok is false, thread will not be
1733  * blocked if there is no data in queue, otherwise, absolute
1734  * time will be checked.
1735  */
1736 int
1737 mqueue_receive(struct mqueue *mq, char *msg_ptr,
1738 	size_t msg_len, unsigned *msg_prio, int waitok,
1739 	const struct timespec *abs_timeout)
1740 {
1741 	struct mqueue_msg *msg;
1742 	struct timespec ets, ts, ts2;
1743 	struct timeval tv;
1744 	int error;
1745 
1746 	if (msg_len < mq->mq_msgsize)
1747 		return (EMSGSIZE);
1748 
1749 	/* O_NONBLOCK case */
1750 	if (!waitok) {
1751 		error = _mqueue_recv(mq, &msg, -1);
1752 		if (error)
1753 			return (error);
1754 		goto received;
1755 	}
1756 
1757 	/* we allow a null timeout (wait forever). */
1758 	if (abs_timeout == NULL) {
1759 		error = _mqueue_recv(mq, &msg, 0);
1760 		if (error)
1761 			return (error);
1762 		goto received;
1763 	}
1764 
1765 	/* try to get a message before checking time */
1766 	error = _mqueue_recv(mq, &msg, -1);
1767 	if (error == 0)
1768 		goto received;
1769 
1770 	if (error != EAGAIN)
1771 		return (error);
1772 
1773 	error = copyin(abs_timeout, &ets, sizeof(ets));
1774 	if (error != 0)
1775 		return (error);
1776 	if (ets.tv_nsec >= 1000000000 || ets.tv_nsec < 0) {
1777 		error = EINVAL;
1778 		return (error);
1779 	}
1780 
1781 	for (;;) {
1782 		ts2 = ets;
1783 		getnanotime(&ts);
1784 		timespecsub(&ts2, &ts);
1785 		if (ts2.tv_sec < 0 || (ts2.tv_sec == 0 && ts2.tv_nsec <= 0)) {
1786 			error = ETIMEDOUT;
1787 			return (error);
1788 		}
1789 		TIMESPEC_TO_TIMEVAL(&tv, &ts2);
1790 		error = _mqueue_recv(mq, &msg, tvtohz(&tv));
1791 		if (error == 0)
1792 			break;
1793 		if (error != ETIMEDOUT)
1794 			return (error);
1795 	}
1796 
1797 received:
1798 	error = mqueue_savemsg(msg, msg_ptr, msg_prio);
1799 	if (error == 0) {
1800 		curthread->td_retval[0] = msg->msg_size;
1801 		curthread->td_retval[1] = 0;
1802 	}
1803 	mqueue_freemsg(msg);
1804 	return (error);
1805 }
1806 
1807 /*
1808  * Common routine to receive a message
1809  */
1810 static int
1811 _mqueue_recv(struct mqueue *mq, struct mqueue_msg **msg, int timo)
1812 {
1813 	int error = 0;
1814 
1815 	mtx_lock(&mq->mq_mutex);
1816 	while ((*msg = TAILQ_FIRST(&mq->mq_msgq)) == NULL && error == 0) {
1817 		if (timo < 0) {
1818 			mtx_unlock(&mq->mq_mutex);
1819 			return (EAGAIN);
1820 		}
1821 		mq->mq_receivers++;
1822 		error = msleep(&mq->mq_receivers, &mq->mq_mutex,
1823 			    PCATCH, "mqrecv", timo);
1824 		mq->mq_receivers--;
1825 		if (error == EAGAIN)
1826 			error = ETIMEDOUT;
1827 	}
1828 	if (*msg != NULL) {
1829 		error = 0;
1830 		TAILQ_REMOVE(&mq->mq_msgq, *msg, msg_link);
1831 		mq->mq_curmsgs--;
1832 		mq->mq_totalbytes -= (*msg)->msg_size;
1833 		if (mq->mq_senders)
1834 			wakeup_one(&mq->mq_senders);
1835 		if (mq->mq_flags & MQ_WSEL) {
1836 			mq->mq_flags &= ~MQ_WSEL;
1837 			selwakeup(&mq->mq_wsel);
1838 		}
1839 		KNOTE_LOCKED(&mq->mq_wsel.si_note, 0);
1840 	}
1841 	if (mq->mq_notifier != NULL && mq->mq_receivers == 0 &&
1842 	    !TAILQ_EMPTY(&mq->mq_msgq)) {
1843 		mqueue_send_notification(mq);
1844 	}
1845 	mtx_unlock(&mq->mq_mutex);
1846 	return (error);
1847 }
1848 
1849 static __inline struct mqueue_notifier *
1850 notifier_alloc(void)
1851 {
1852 	return (uma_zalloc(mqnoti_zone, M_WAITOK | M_ZERO));
1853 }
1854 
1855 static __inline void
1856 notifier_free(struct mqueue_notifier *p)
1857 {
1858 	uma_zfree(mqnoti_zone, p);
1859 }
1860 
1861 static struct mqueue_notifier *
1862 notifier_search(struct proc *p, int fd)
1863 {
1864 	struct mqueue_notifier *nt;
1865 
1866 	LIST_FOREACH(nt, &p->p_mqnotifier, nt_link) {
1867 		if (nt->nt_ksi.ksi_mqd == fd)
1868 			break;
1869 	}
1870 	return (nt);
1871 }
1872 
1873 static __inline void
1874 notifier_insert(struct proc *p, struct mqueue_notifier *nt)
1875 {
1876 	LIST_INSERT_HEAD(&p->p_mqnotifier, nt, nt_link);
1877 }
1878 
1879 static __inline void
1880 notifier_delete(struct proc *p, struct mqueue_notifier *nt)
1881 {
1882 	LIST_REMOVE(nt, nt_link);
1883 	notifier_free(nt);
1884 }
1885 
1886 static void
1887 notifier_remove(struct proc *p, struct mqueue *mq, int fd)
1888 {
1889 	struct mqueue_notifier *nt;
1890 
1891 	mtx_assert(&mq->mq_mutex, MA_OWNED);
1892 	PROC_LOCK(p);
1893 	nt = notifier_search(p, fd);
1894 	if (nt != NULL) {
1895 		if (mq->mq_notifier == nt)
1896 			mq->mq_notifier = NULL;
1897 		sigqueue_take(&nt->nt_ksi);
1898 		notifier_delete(p, nt);
1899 	}
1900 	PROC_UNLOCK(p);
1901 }
1902 
1903 /*
1904  * Syscall to open a message queue.
1905  */
1906 int
1907 kmq_open(struct thread *td, struct kmq_open_args *uap)
1908 {
1909 	char path[MQFS_NAMELEN + 1];
1910 	struct mq_attr attr, *pattr;
1911 	struct mqfs_node *pn;
1912 	struct filedesc *fdp;
1913 	struct file *fp;
1914 	struct mqueue *mq;
1915 	int fd, error, len, flags, cmode;
1916 
1917 	if ((uap->flags & O_ACCMODE) == O_ACCMODE)
1918 		return (EINVAL);
1919 
1920 	fdp = td->td_proc->p_fd;
1921 	flags = FFLAGS(uap->flags);
1922 	cmode = (((uap->mode & ~fdp->fd_cmask) & ALLPERMS) & ~S_ISTXT);
1923 	mq = NULL;
1924 	if ((flags & O_CREAT) && (uap->attr != NULL)) {
1925 		error = copyin(uap->attr, &attr, sizeof(attr));
1926 		if (error)
1927 			return (error);
1928 		if (attr.mq_maxmsg <= 0 || attr.mq_maxmsg > maxmsg)
1929 			return (EINVAL);
1930 		if (attr.mq_msgsize <= 0 || attr.mq_msgsize > maxmsgsize)
1931 			return (EINVAL);
1932 		pattr = &attr;
1933 	} else
1934 		pattr = NULL;
1935 
1936 	error = copyinstr(uap->path, path, MQFS_NAMELEN + 1, NULL);
1937         if (error)
1938 		return (error);
1939 
1940 	/*
1941 	 * The first character of name must be a slash  (/) character
1942 	 * and the remaining characters of name cannot include any slash
1943 	 * characters.
1944 	 */
1945 	len = strlen(path);
1946 	if (len < 2  || path[0] != '/' || index(path + 1, '/') != NULL)
1947 		return (EINVAL);
1948 
1949 	error = falloc(td, &fp, &fd);
1950 	if (error)
1951 		return (error);
1952 
1953 	sx_xlock(&mqfs_data.mi_lock);
1954 	pn = mqfs_search(mqfs_data.mi_root, path + 1, len - 1);
1955 	if (pn == NULL) {
1956 		if (!(flags & O_CREAT)) {
1957 			error = ENOENT;
1958 		} else {
1959 			mq = mqueue_alloc(pattr);
1960 			if (mq == NULL) {
1961 				error = ENFILE;
1962 			} else {
1963 				pn = mqfs_create_file(mqfs_data.mi_root,
1964 				         path + 1, len - 1, td->td_ucred,
1965 					 cmode);
1966 				if (pn == NULL) {
1967 					error = ENOSPC;
1968 					mqueue_free(mq);
1969 				}
1970 			}
1971 		}
1972 
1973 		if (error == 0) {
1974 			pn->mn_data = mq;
1975 		}
1976 	} else {
1977 		if ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL)) {
1978 			error = EEXIST;
1979 		} else {
1980 			int acc_mode = 0;
1981 
1982 			if (flags & FREAD)
1983 				acc_mode |= VREAD;
1984 			if (flags & FWRITE)
1985 				acc_mode |= VWRITE;
1986 			error = vaccess(VREG, pn->mn_mode, pn->mn_uid,
1987 				    pn->mn_gid, acc_mode, td->td_ucred, NULL);
1988 		}
1989 	}
1990 
1991 	if (error) {
1992 		sx_xunlock(&mqfs_data.mi_lock);
1993 		fdclose(fdp, fp, fd, td);
1994 		fdrop(fp, td);
1995 		return (error);
1996 	}
1997 
1998 	mqnode_addref(pn);
1999 	sx_xunlock(&mqfs_data.mi_lock);
2000 
2001 	finit(fp, flags & (FREAD | FWRITE | O_NONBLOCK), DTYPE_MQUEUE, pn,
2002 	    &mqueueops);
2003 
2004 	FILEDESC_XLOCK(fdp);
2005 	if (fdp->fd_ofiles[fd] == fp)
2006 		fdp->fd_ofileflags[fd] |= UF_EXCLOSE;
2007 	FILEDESC_XUNLOCK(fdp);
2008 	td->td_retval[0] = fd;
2009 	fdrop(fp, td);
2010 	return (0);
2011 }
2012 
2013 /*
2014  * Syscall to unlink a message queue.
2015  */
2016 int
2017 kmq_unlink(struct thread *td, struct kmq_unlink_args *uap)
2018 {
2019 	char path[MQFS_NAMELEN+1];
2020 	struct mqfs_node *pn;
2021 	int error, len;
2022 
2023 	error = copyinstr(uap->path, path, MQFS_NAMELEN + 1, NULL);
2024         if (error)
2025 		return (error);
2026 
2027 	len = strlen(path);
2028 	if (len < 2  || path[0] != '/' || index(path + 1, '/') != NULL)
2029 		return (EINVAL);
2030 
2031 	sx_xlock(&mqfs_data.mi_lock);
2032 	pn = mqfs_search(mqfs_data.mi_root, path + 1, len - 1);
2033 	if (pn != NULL)
2034 		error = do_unlink(pn, td->td_ucred);
2035 	else
2036 		error = ENOENT;
2037 	sx_xunlock(&mqfs_data.mi_lock);
2038 	return (error);
2039 }
2040 
2041 typedef int (*_fgetf)(struct thread *, int, struct file **);
2042 
2043 /*
2044  * Get message queue by giving file slot
2045  */
2046 static int
2047 _getmq(struct thread *td, int fd, _fgetf func,
2048        struct file **fpp, struct mqfs_node **ppn, struct mqueue **pmq)
2049 {
2050 	struct mqfs_node *pn;
2051 	int error;
2052 
2053 	error = func(td, fd, fpp);
2054 	if (error)
2055 		return (error);
2056 	if (&mqueueops != (*fpp)->f_ops) {
2057 		fdrop(*fpp, td);
2058 		return (EBADF);
2059 	}
2060 	pn = (*fpp)->f_data;
2061 	if (ppn)
2062 		*ppn = pn;
2063 	if (pmq)
2064 		*pmq = pn->mn_data;
2065 	return (0);
2066 }
2067 
2068 static __inline int
2069 getmq(struct thread *td, int fd, struct file **fpp, struct mqfs_node **ppn,
2070 	struct mqueue **pmq)
2071 {
2072 	return _getmq(td, fd, fget, fpp, ppn, pmq);
2073 }
2074 
2075 static __inline int
2076 getmq_read(struct thread *td, int fd, struct file **fpp,
2077 	 struct mqfs_node **ppn, struct mqueue **pmq)
2078 {
2079 	return _getmq(td, fd, fget_read, fpp, ppn, pmq);
2080 }
2081 
2082 static __inline int
2083 getmq_write(struct thread *td, int fd, struct file **fpp,
2084 	struct mqfs_node **ppn, struct mqueue **pmq)
2085 {
2086 	return _getmq(td, fd, fget_write, fpp, ppn, pmq);
2087 }
2088 
2089 int
2090 kmq_setattr(struct thread *td, struct kmq_setattr_args *uap)
2091 {
2092 	struct mqueue *mq;
2093 	struct file *fp;
2094 	struct mq_attr attr, oattr;
2095 	u_int oflag, flag;
2096 	int error;
2097 
2098 	if (uap->attr) {
2099 		error = copyin(uap->attr, &attr, sizeof(attr));
2100 		if (error)
2101 			return (error);
2102 		if (attr.mq_flags & ~O_NONBLOCK)
2103 			return (EINVAL);
2104 	}
2105 	error = getmq(td, uap->mqd, &fp, NULL, &mq);
2106 	if (error)
2107 		return (error);
2108 	oattr.mq_maxmsg  = mq->mq_maxmsg;
2109 	oattr.mq_msgsize = mq->mq_msgsize;
2110 	oattr.mq_curmsgs = mq->mq_curmsgs;
2111 	if (uap->attr) {
2112 		do {
2113 			oflag = flag = fp->f_flag;
2114 			flag &= ~O_NONBLOCK;
2115 			flag |= (attr.mq_flags & O_NONBLOCK);
2116 		} while (atomic_cmpset_int(&fp->f_flag, oflag, flag) == 0);
2117 	} else
2118 		oflag = fp->f_flag;
2119 	oattr.mq_flags = (O_NONBLOCK & oflag);
2120 	fdrop(fp, td);
2121 	if (uap->oattr)
2122 		error = copyout(&oattr, uap->oattr, sizeof(oattr));
2123 	return (error);
2124 }
2125 
2126 int
2127 kmq_timedreceive(struct thread *td, struct kmq_timedreceive_args *uap)
2128 {
2129 	struct mqueue *mq;
2130 	struct file *fp;
2131 	int error;
2132 	int waitok;
2133 
2134 	error = getmq_read(td, uap->mqd, &fp, NULL, &mq);
2135 	if (error)
2136 		return (error);
2137 	waitok = !(fp->f_flag & O_NONBLOCK);
2138 	error = mqueue_receive(mq, uap->msg_ptr, uap->msg_len,
2139 		uap->msg_prio, waitok, uap->abs_timeout);
2140 	fdrop(fp, td);
2141 	return (error);
2142 }
2143 
2144 int
2145 kmq_timedsend(struct thread *td, struct kmq_timedsend_args *uap)
2146 {
2147 	struct mqueue *mq;
2148 	struct file *fp;
2149 	int error, waitok;
2150 
2151 	error = getmq_write(td, uap->mqd, &fp, NULL, &mq);
2152 	if (error)
2153 		return (error);
2154 	waitok = !(fp->f_flag & O_NONBLOCK);
2155 	error = mqueue_send(mq, uap->msg_ptr, uap->msg_len,
2156 		uap->msg_prio, waitok, uap->abs_timeout);
2157 	fdrop(fp, td);
2158 	return (error);
2159 }
2160 
2161 int
2162 kmq_notify(struct thread *td, struct kmq_notify_args *uap)
2163 {
2164 	struct sigevent ev;
2165 	struct filedesc *fdp;
2166 	struct proc *p;
2167 	struct mqueue *mq;
2168 	struct file *fp;
2169 	struct mqueue_notifier *nt, *newnt = NULL;
2170 	int error;
2171 
2172 	p = td->td_proc;
2173 	fdp = td->td_proc->p_fd;
2174 	if (uap->sigev) {
2175 		error = copyin(uap->sigev, &ev, sizeof(ev));
2176 		if (error)
2177 			return (error);
2178 		if (ev.sigev_notify != SIGEV_SIGNAL &&
2179 		    ev.sigev_notify != SIGEV_THREAD_ID &&
2180 		    ev.sigev_notify != SIGEV_NONE)
2181 			return (EINVAL);
2182 		if ((ev.sigev_notify == SIGEV_SIGNAL ||
2183 		     ev.sigev_notify == SIGEV_THREAD_ID) &&
2184 			!_SIG_VALID(ev.sigev_signo))
2185 			return (EINVAL);
2186 	}
2187 	error = getmq(td, uap->mqd, &fp, NULL, &mq);
2188 	if (error)
2189 		return (error);
2190 again:
2191 	FILEDESC_SLOCK(fdp);
2192 	if (fget_locked(fdp, uap->mqd) != fp) {
2193 		FILEDESC_SUNLOCK(fdp);
2194 		error = EBADF;
2195 		goto out;
2196 	}
2197 	mtx_lock(&mq->mq_mutex);
2198 	FILEDESC_SUNLOCK(fdp);
2199 	if (uap->sigev != NULL) {
2200 		if (mq->mq_notifier != NULL) {
2201 			error = EBUSY;
2202 		} else {
2203 			PROC_LOCK(p);
2204 			nt = notifier_search(p, uap->mqd);
2205 			if (nt == NULL) {
2206 				if (newnt == NULL) {
2207 					PROC_UNLOCK(p);
2208 					mtx_unlock(&mq->mq_mutex);
2209 					newnt = notifier_alloc();
2210 					goto again;
2211 				}
2212 			}
2213 
2214 			if (nt != NULL) {
2215 				sigqueue_take(&nt->nt_ksi);
2216 				if (newnt != NULL) {
2217 					notifier_free(newnt);
2218 					newnt = NULL;
2219 				}
2220 			} else {
2221 				nt = newnt;
2222 				newnt = NULL;
2223 				ksiginfo_init(&nt->nt_ksi);
2224 				nt->nt_ksi.ksi_flags |= KSI_INS | KSI_EXT;
2225 				nt->nt_ksi.ksi_code = SI_MESGQ;
2226 				nt->nt_proc = p;
2227 				nt->nt_ksi.ksi_mqd = uap->mqd;
2228 				notifier_insert(p, nt);
2229 			}
2230 			nt->nt_sigev = ev;
2231 			mq->mq_notifier = nt;
2232 			PROC_UNLOCK(p);
2233 			/*
2234 			 * if there is no receivers and message queue
2235 			 * is not empty, we should send notification
2236 			 * as soon as possible.
2237 			 */
2238 			if (mq->mq_receivers == 0 &&
2239 			    !TAILQ_EMPTY(&mq->mq_msgq))
2240 				mqueue_send_notification(mq);
2241 		}
2242 	} else {
2243 		notifier_remove(p, mq, uap->mqd);
2244 	}
2245 	mtx_unlock(&mq->mq_mutex);
2246 
2247 out:
2248 	fdrop(fp, td);
2249 	if (newnt != NULL)
2250 		notifier_free(newnt);
2251 	return (error);
2252 }
2253 
2254 static void
2255 mqueue_fdclose(struct thread *td, int fd, struct file *fp)
2256 {
2257 	struct filedesc *fdp;
2258 	struct mqueue *mq;
2259 
2260 	fdp = td->td_proc->p_fd;
2261 	FILEDESC_LOCK_ASSERT(fdp);
2262 
2263 	if (fp->f_ops == &mqueueops) {
2264 		mq = FPTOMQ(fp);
2265 		mtx_lock(&mq->mq_mutex);
2266 		notifier_remove(td->td_proc, mq, fd);
2267 
2268 		/* have to wakeup thread in same process */
2269 		if (mq->mq_flags & MQ_RSEL) {
2270 			mq->mq_flags &= ~MQ_RSEL;
2271 			selwakeup(&mq->mq_rsel);
2272 		}
2273 		if (mq->mq_flags & MQ_WSEL) {
2274 			mq->mq_flags &= ~MQ_WSEL;
2275 			selwakeup(&mq->mq_wsel);
2276 		}
2277 		mtx_unlock(&mq->mq_mutex);
2278 	}
2279 }
2280 
2281 static void
2282 mq_proc_exit(void *arg __unused, struct proc *p)
2283 {
2284 	struct filedesc *fdp;
2285 	struct file *fp;
2286 	struct mqueue *mq;
2287 	int i;
2288 
2289 	fdp = p->p_fd;
2290 	FILEDESC_SLOCK(fdp);
2291 	for (i = 0; i < fdp->fd_nfiles; ++i) {
2292 		fp = fget_locked(fdp, i);
2293 		if (fp != NULL && fp->f_ops == &mqueueops) {
2294 			mq = FPTOMQ(fp);
2295 			mtx_lock(&mq->mq_mutex);
2296 			notifier_remove(p, FPTOMQ(fp), i);
2297 			mtx_unlock(&mq->mq_mutex);
2298 		}
2299 	}
2300 	FILEDESC_SUNLOCK(fdp);
2301 	KASSERT(LIST_EMPTY(&p->p_mqnotifier), ("mq notifiers left"));
2302 }
2303 
2304 static int
2305 mqf_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
2306 	int flags, struct thread *td)
2307 {
2308 	return (EOPNOTSUPP);
2309 }
2310 
2311 static int
2312 mqf_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
2313 	int flags, struct thread *td)
2314 {
2315 	return (EOPNOTSUPP);
2316 }
2317 
2318 static int
2319 mqf_truncate(struct file *fp, off_t length, struct ucred *active_cred,
2320     struct thread *td)
2321 {
2322 
2323 	return (EINVAL);
2324 }
2325 
2326 static int
2327 mqf_ioctl(struct file *fp, u_long cmd, void *data,
2328 	struct ucred *active_cred, struct thread *td)
2329 {
2330 	return (ENOTTY);
2331 }
2332 
2333 static int
2334 mqf_poll(struct file *fp, int events, struct ucred *active_cred,
2335 	struct thread *td)
2336 {
2337 	struct mqueue *mq = FPTOMQ(fp);
2338 	int revents = 0;
2339 
2340 	mtx_lock(&mq->mq_mutex);
2341 	if (events & (POLLIN | POLLRDNORM)) {
2342 		if (mq->mq_curmsgs) {
2343 			revents |= events & (POLLIN | POLLRDNORM);
2344 		} else {
2345 			mq->mq_flags |= MQ_RSEL;
2346 			selrecord(td, &mq->mq_rsel);
2347  		}
2348 	}
2349 	if (events & POLLOUT) {
2350 		if (mq->mq_curmsgs < mq->mq_maxmsg)
2351 			revents |= POLLOUT;
2352 		else {
2353 			mq->mq_flags |= MQ_WSEL;
2354 			selrecord(td, &mq->mq_wsel);
2355 		}
2356 	}
2357 	mtx_unlock(&mq->mq_mutex);
2358 	return (revents);
2359 }
2360 
2361 static int
2362 mqf_close(struct file *fp, struct thread *td)
2363 {
2364 	struct mqfs_node *pn;
2365 
2366 	fp->f_ops = &badfileops;
2367 	pn = fp->f_data;
2368 	fp->f_data = NULL;
2369 	sx_xlock(&mqfs_data.mi_lock);
2370 	mqnode_release(pn);
2371 	sx_xunlock(&mqfs_data.mi_lock);
2372 	return (0);
2373 }
2374 
2375 static int
2376 mqf_stat(struct file *fp, struct stat *st, struct ucred *active_cred,
2377 	struct thread *td)
2378 {
2379 	struct mqfs_node *pn = fp->f_data;
2380 
2381 	bzero(st, sizeof *st);
2382 	st->st_atimespec = pn->mn_atime;
2383 	st->st_mtimespec = pn->mn_mtime;
2384 	st->st_ctimespec = pn->mn_ctime;
2385 	st->st_birthtimespec = pn->mn_birth;
2386 	st->st_uid = pn->mn_uid;
2387 	st->st_gid = pn->mn_gid;
2388 	st->st_mode = S_IFIFO | pn->mn_mode;
2389 	return (0);
2390 }
2391 
2392 static int
2393 mqf_kqfilter(struct file *fp, struct knote *kn)
2394 {
2395 	struct mqueue *mq = FPTOMQ(fp);
2396 	int error = 0;
2397 
2398 	if (kn->kn_filter == EVFILT_READ) {
2399 		kn->kn_fop = &mq_rfiltops;
2400 		knlist_add(&mq->mq_rsel.si_note, kn, 0);
2401 	} else if (kn->kn_filter == EVFILT_WRITE) {
2402 		kn->kn_fop = &mq_wfiltops;
2403 		knlist_add(&mq->mq_wsel.si_note, kn, 0);
2404 	} else
2405 		error = EINVAL;
2406 	return (error);
2407 }
2408 
2409 static void
2410 filt_mqdetach(struct knote *kn)
2411 {
2412 	struct mqueue *mq = FPTOMQ(kn->kn_fp);
2413 
2414 	if (kn->kn_filter == EVFILT_READ)
2415 		knlist_remove(&mq->mq_rsel.si_note, kn, 0);
2416 	else if (kn->kn_filter == EVFILT_WRITE)
2417 		knlist_remove(&mq->mq_wsel.si_note, kn, 0);
2418 	else
2419 		panic("filt_mqdetach");
2420 }
2421 
2422 static int
2423 filt_mqread(struct knote *kn, long hint)
2424 {
2425 	struct mqueue *mq = FPTOMQ(kn->kn_fp);
2426 
2427 	mtx_assert(&mq->mq_mutex, MA_OWNED);
2428 	return (mq->mq_curmsgs != 0);
2429 }
2430 
2431 static int
2432 filt_mqwrite(struct knote *kn, long hint)
2433 {
2434 	struct mqueue *mq = FPTOMQ(kn->kn_fp);
2435 
2436 	mtx_assert(&mq->mq_mutex, MA_OWNED);
2437 	return (mq->mq_curmsgs < mq->mq_maxmsg);
2438 }
2439 
2440 static struct fileops mqueueops = {
2441 	.fo_read		= mqf_read,
2442 	.fo_write		= mqf_write,
2443 	.fo_truncate		= mqf_truncate,
2444 	.fo_ioctl		= mqf_ioctl,
2445 	.fo_poll		= mqf_poll,
2446 	.fo_kqfilter		= mqf_kqfilter,
2447 	.fo_stat		= mqf_stat,
2448 	.fo_close		= mqf_close
2449 };
2450 
2451 static struct vop_vector mqfs_vnodeops = {
2452 	.vop_default 		= &default_vnodeops,
2453 	.vop_access		= mqfs_access,
2454 	.vop_cachedlookup	= mqfs_lookup,
2455 	.vop_lookup		= vfs_cache_lookup,
2456 	.vop_reclaim		= mqfs_reclaim,
2457 	.vop_create		= mqfs_create,
2458 	.vop_remove		= mqfs_remove,
2459 	.vop_inactive		= mqfs_inactive,
2460 	.vop_open		= mqfs_open,
2461 	.vop_close		= mqfs_close,
2462 	.vop_getattr		= mqfs_getattr,
2463 	.vop_setattr		= mqfs_setattr,
2464 	.vop_read		= mqfs_read,
2465 	.vop_write		= VOP_EOPNOTSUPP,
2466 	.vop_readdir		= mqfs_readdir,
2467 	.vop_mkdir		= VOP_EOPNOTSUPP,
2468 	.vop_rmdir		= VOP_EOPNOTSUPP
2469 };
2470 
2471 static struct vfsops mqfs_vfsops = {
2472 	.vfs_init 		= mqfs_init,
2473 	.vfs_uninit		= mqfs_uninit,
2474 	.vfs_mount		= mqfs_mount,
2475 	.vfs_unmount		= mqfs_unmount,
2476 	.vfs_root		= mqfs_root,
2477 	.vfs_statfs		= mqfs_statfs,
2478 };
2479 
2480 SYSCALL_MODULE_HELPER(kmq_open);
2481 SYSCALL_MODULE_HELPER(kmq_setattr);
2482 SYSCALL_MODULE_HELPER(kmq_timedsend);
2483 SYSCALL_MODULE_HELPER(kmq_timedreceive);
2484 SYSCALL_MODULE_HELPER(kmq_notify);
2485 SYSCALL_MODULE_HELPER(kmq_unlink);
2486 
2487 VFS_SET(mqfs_vfsops, mqueuefs, VFCF_SYNTHETIC);
2488 MODULE_VERSION(mqueuefs, 1);
2489