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      1 /*	$NetBSD: uipc_usrreq.c,v 1.212 2026/10/02 01:33:44 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1998, 2000, 2004, 2008, 2009, 2020 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
      9  * NASA Ames Research Center, and by Andrew Doran.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     30  * POSSIBILITY OF SUCH DAMAGE.
     31  */
     32 
     33 /*
     34  * Copyright (c) 1982, 1986, 1989, 1991, 1993
     35  *	The Regents of the University of California.  All rights reserved.
     36  *
     37  * Redistribution and use in source and binary forms, with or without
     38  * modification, are permitted provided that the following conditions
     39  * are met:
     40  * 1. Redistributions of source code must retain the above copyright
     41  *    notice, this list of conditions and the following disclaimer.
     42  * 2. Redistributions in binary form must reproduce the above copyright
     43  *    notice, this list of conditions and the following disclaimer in the
     44  *    documentation and/or other materials provided with the distribution.
     45  * 3. Neither the name of the University nor the names of its contributors
     46  *    may be used to endorse or promote products derived from this software
     47  *    without specific prior written permission.
     48  *
     49  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     50  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     51  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     52  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     53  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     54  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     55  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     56  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     57  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     58  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     59  * SUCH DAMAGE.
     60  *
     61  *	@(#)uipc_usrreq.c	8.9 (Berkeley) 5/14/95
     62  */
     63 
     64 /*
     65  * Copyright (c) 1997 Christopher G. Demetriou.  All rights reserved.
     66  *
     67  * Redistribution and use in source and binary forms, with or without
     68  * modification, are permitted provided that the following conditions
     69  * are met:
     70  * 1. Redistributions of source code must retain the above copyright
     71  *    notice, this list of conditions and the following disclaimer.
     72  * 2. Redistributions in binary form must reproduce the above copyright
     73  *    notice, this list of conditions and the following disclaimer in the
     74  *    documentation and/or other materials provided with the distribution.
     75  * 3. All advertising materials mentioning features or use of this software
     76  *    must display the following acknowledgement:
     77  *	This product includes software developed by the University of
     78  *	California, Berkeley and its contributors.
     79  * 4. Neither the name of the University nor the names of its contributors
     80  *    may be used to endorse or promote products derived from this software
     81  *    without specific prior written permission.
     82  *
     83  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     84  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     85  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     86  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     87  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     88  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     89  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     90  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     91  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     92  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     93  * SUCH DAMAGE.
     94  *
     95  *	@(#)uipc_usrreq.c	8.9 (Berkeley) 5/14/95
     96  */
     97 
     98 #include <sys/cdefs.h>
     99 __KERNEL_RCSID(0, "$NetBSD: uipc_usrreq.c,v 1.212 2026/10/02 01:33:44 riastradh Exp $");
    100 
    101 #ifdef _KERNEL_OPT
    102 #include "opt_compat_netbsd.h"
    103 #endif
    104 
    105 #include <sys/param.h>
    106 #include <sys/types.h>
    107 
    108 #include <sys/atomic.h>
    109 #include <sys/compat_stub.h>
    110 #include <sys/domain.h>
    111 #include <sys/file.h>
    112 #include <sys/filedesc.h>
    113 #include <sys/kauth.h>
    114 #include <sys/kernel.h>
    115 #include <sys/kmem.h>
    116 #include <sys/kthread.h>
    117 #include <sys/mbuf.h>
    118 #include <sys/namei.h>
    119 #include <sys/proc.h>
    120 #include <sys/protosw.h>
    121 #include <sys/sdt.h>
    122 #include <sys/socket.h>
    123 #include <sys/socketvar.h>
    124 #include <sys/stat.h>
    125 #include <sys/systm.h>
    126 #include <sys/uidinfo.h>
    127 #include <sys/un.h>
    128 #include <sys/unpcb.h>
    129 #include <sys/vnode.h>
    130 
    131 #include <compat/net/route_70.h>
    132 #include <compat/sys/socket.h>
    133 
    134 /*
    135  * Unix communications domain.
    136  *
    137  * TODO:
    138  *	RDM
    139  *	rethink name space problems
    140  *	need a proper out-of-band
    141  *
    142  * Notes on locking:
    143  *
    144  * The generic rules noted in uipc_socket2.c apply.  In addition:
    145  *
    146  * o We have a global lock, uipc_lock.
    147  *
    148  * o All datagram sockets are locked by uipc_lock.
    149  *
    150  * o For stream socketpairs, the two endpoints are created sharing the same
    151  *   independent lock.  Sockets presented to PRU_CONNECT2 must already have
    152  *   matching locks.
    153  *
    154  * o Stream sockets created via socket() start life with their own
    155  *   independent lock.
    156  *
    157  * o Stream connections to a named endpoint are slightly more complicated.
    158  *   Sockets that have called listen() have their lock pointer mutated to
    159  *   the global uipc_lock.  When establishing a connection, the connecting
    160  *   socket also has its lock mutated to uipc_lock, which matches the head
    161  *   (listening socket).  We create a new socket for accept() to return, and
    162  *   that also shares the head's lock.  Until the connection is completely
    163  *   done on both ends, all three sockets are locked by uipc_lock.  Once the
    164  *   connection is complete, the association with the head's lock is broken.
    165  *   The connecting socket and the socket returned from accept() have their
    166  *   lock pointers mutated away from uipc_lock, and back to the connecting
    167  *   socket's original, independent lock.  The head continues to be locked
    168  *   by uipc_lock.
    169  *
    170  * o If uipc_lock is determined to be a significant source of contention,
    171  *   it could easily be hashed out.  It is difficult to simply make it an
    172  *   independent lock because of visibility / garbage collection issues:
    173  *   if a socket has been associated with a lock at any point, that lock
    174  *   must remain valid until the socket is no longer visible in the system.
    175  *   The lock must not be freed or otherwise destroyed until any sockets
    176  *   that had referenced it have also been destroyed.
    177  */
    178 const struct sockaddr_un sun_noname = {
    179 	.sun_len = offsetof(struct sockaddr_un, sun_path),
    180 	.sun_family = AF_LOCAL,
    181 };
    182 
    183 /* prototype for fake inode numbers */
    184 #ifdef __HAVE_ATOMIC64_OPS
    185 volatile uint64_t	unp_ino __cacheline_aligned;
    186 #else
    187 struct {
    188 	uint64_t	num;
    189 	kmutex_t	lock;
    190 } unp_ino __cacheline_aligned;
    191 #endif
    192 
    193 static struct mbuf * unp_addsockcred(struct lwp *, struct mbuf *);
    194 static void   unp_discard_later(file_t *);
    195 static void   unp_discard_now(file_t *);
    196 static void   unp_disconnect1(struct unpcb *);
    197 static bool   unp_drop(struct unpcb *, int);
    198 static int    unp_internalize(struct mbuf **);
    199 static void   unp_mark(file_t *);
    200 static void   unp_scan(struct mbuf *, void (*)(file_t *), int);
    201 static void   unp_shutdown1(struct unpcb *);
    202 static void   unp_thread(void *);
    203 static void   unp_thread_kick(void);
    204 
    205 static kmutex_t *uipc_lock;
    206 
    207 static kcondvar_t unp_thread_cv;
    208 static lwp_t *unp_thread_lwp;
    209 static SLIST_HEAD(,file) unp_thread_discard;
    210 static int unp_defer;
    211 static struct sysctllog *usrreq_sysctllog;
    212 static void unp_sysctl_create(void);
    213 
    214 /* Compat interface */
    215 
    216 struct mbuf * stub_compat_70_unp_addsockcred(lwp_t *, struct mbuf *);
    217 
    218 struct mbuf * stub_compat_70_unp_addsockcred(struct lwp *lwp,
    219     struct mbuf *control)
    220 {
    221 
    222 /* just copy our initial argument */
    223 	return control;
    224 }
    225 
    226 bool compat70_ocreds_valid = false;
    227 
    228 /*
    229  * Initialize Unix protocols.
    230  */
    231 void
    232 uipc_init(void)
    233 {
    234 	int error;
    235 
    236 	unp_sysctl_create();
    237 
    238 	uipc_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
    239 	cv_init(&unp_thread_cv, "unpgc");
    240 
    241 	error = kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL, unp_thread,
    242 	    NULL, &unp_thread_lwp, "unpgc");
    243 	if (error != 0)
    244 		panic("uipc_init %d", error);
    245 
    246 #ifndef __HAVE_ATOMIC64_OPS
    247 	mutex_init(&unp_ino.lock, MUTEX_DEFAULT, IPL_NONE);
    248 #endif
    249 }
    250 
    251 static void
    252 unp_connid(struct lwp *l, struct unpcb *unp, int flags)
    253 {
    254 	unp->unp_connid.unp_pid = l->l_proc->p_pid;
    255 	unp->unp_connid.unp_euid = kauth_cred_geteuid(l->l_cred);
    256 	unp->unp_connid.unp_egid = kauth_cred_getegid(l->l_cred);
    257 	unp->unp_flags |= flags;
    258 }
    259 
    260 /*
    261  * A connection succeeded: disassociate both endpoints from the head's
    262  * lock, and make them share their own lock.  There is a race here: for
    263  * a very brief time one endpoint will be locked by a different lock
    264  * than the other end.  However, since the current thread holds the old
    265  * lock (the listening socket's lock, the head) access can still only be
    266  * made to one side of the connection.
    267  */
    268 static void
    269 unp_setpeerlocks(struct socket *so, struct socket *so2)
    270 {
    271 	struct unpcb *unp;
    272 	kmutex_t *lock;
    273 
    274 	KASSERT(solocked2(so, so2));
    275 
    276 	/*
    277 	 * Bail out if either end of the socket is not yet fully
    278 	 * connected or accepted.  We only break the lock association
    279 	 * with the head when the pair of sockets stand completely
    280 	 * on their own.
    281 	 */
    282 	KASSERT(so->so_head == NULL);
    283 	if (so2->so_head != NULL)
    284 		return;
    285 
    286 	/*
    287 	 * Drop references to old lock.  A third reference (from the
    288 	 * queue head) must be held as we still hold its lock.  Bonus:
    289 	 * we don't need to worry about garbage collecting the lock.
    290 	 */
    291 	lock = so->so_lock;
    292 	KASSERT(lock == uipc_lock);
    293 	mutex_obj_free(lock);
    294 	mutex_obj_free(lock);
    295 
    296 	/*
    297 	 * Grab stream lock from the initiator and share between the two
    298 	 * endpoints.  Issue memory barrier to ensure all modifications
    299 	 * become globally visible before the lock change.  so2 is
    300 	 * assumed not to have a stream lock, because it was created
    301 	 * purely for the server side to accept this connection and
    302 	 * started out life using the domain-wide lock.
    303 	 */
    304 	unp = sotounpcb(so);
    305 	KASSERT(unp->unp_streamlock != NULL);
    306 	KASSERT(sotounpcb(so2)->unp_streamlock == NULL);
    307 	lock = unp->unp_streamlock;
    308 	unp->unp_streamlock = NULL;
    309 	mutex_obj_hold(lock);
    310 	/*
    311 	 * Ensure lock is initialized before publishing it with
    312 	 * solockreset.  Pairs with atomic_load_consume in solock and
    313 	 * various loops to reacquire lock after wakeup.
    314 	 */
    315 	membar_release();
    316 	/*
    317 	 * possible race if lock is not held - see comment in
    318 	 * uipc_usrreq(PRU_ACCEPT).
    319 	 */
    320 	KASSERT(mutex_owned(lock));
    321 	solockreset(so, lock);
    322 	solockreset(so2, lock);
    323 }
    324 
    325 /*
    326  * Reset a socket's lock back to the domain-wide lock.
    327  */
    328 static void
    329 unp_resetlock(struct socket *so)
    330 {
    331 	kmutex_t *olock, *nlock;
    332 	struct unpcb *unp;
    333 
    334 	KASSERT(solocked(so));
    335 
    336 	olock = so->so_lock;
    337 	nlock = uipc_lock;
    338 	if (olock == nlock)
    339 		return;
    340 	unp = sotounpcb(so);
    341 	KASSERT(unp->unp_streamlock == NULL);
    342 	unp->unp_streamlock = olock;
    343 	mutex_obj_hold(nlock);
    344 	mutex_enter(nlock);
    345 	solockreset(so, nlock);
    346 	mutex_exit(olock);
    347 }
    348 
    349 static void
    350 unp_free(struct unpcb *unp)
    351 {
    352 	if (unp->unp_addr)
    353 		free(unp->unp_addr, M_SONAME);
    354 	if (unp->unp_streamlock != NULL)
    355 		mutex_obj_free(unp->unp_streamlock);
    356 	kmem_free(unp, sizeof(*unp));
    357 }
    358 
    359 static int
    360 unp_output(struct mbuf *m, struct mbuf *control, struct unpcb *unp)
    361 {
    362 	struct socket *so2;
    363 	const struct sockaddr_un *sun;
    364 
    365 	/* XXX: server side closed the socket */
    366 	if (unp->unp_conn == NULL)
    367 		return SET_ERROR(ECONNREFUSED);
    368 	so2 = unp->unp_conn->unp_socket;
    369 
    370 	KASSERT(solocked(so2));
    371 
    372 	if (unp->unp_addr)
    373 		sun = unp->unp_addr;
    374 	else
    375 		sun = &sun_noname;
    376 	if (unp->unp_conn->unp_flags & UNP_WANTCRED)
    377 		control = unp_addsockcred(curlwp, control);
    378 	if (unp->unp_conn->unp_flags & UNP_OWANTCRED)
    379 		MODULE_HOOK_CALL(uipc_unp_70_hook, (curlwp, control),
    380 		    stub_compat_70_unp_addsockcred(curlwp, control), control);
    381 	if (sbappendaddr(&so2->so_rcv, (const struct sockaddr *)sun, m,
    382 	    control) == 0) {
    383 		unp_dispose(control);
    384 		m_freem(control);
    385 		m_freem(m);
    386 		/* Don't call soroverflow because we're returning this
    387 		 * error directly to the sender. */
    388 		so2->so_rcv.sb_overflowed++;
    389 		return SET_ERROR(ENOBUFS);
    390 	} else {
    391 		sorwakeup(so2);
    392 		return 0;
    393 	}
    394 }
    395 
    396 static void
    397 unp_setaddr(struct socket *so, struct sockaddr *nam, bool peeraddr)
    398 {
    399 	const struct sockaddr_un *sun = NULL;
    400 	struct unpcb *unp;
    401 
    402 	KASSERT(solocked(so));
    403 	unp = sotounpcb(so);
    404 
    405 	if (peeraddr) {
    406 		if (unp->unp_conn && unp->unp_conn->unp_addr)
    407 			sun = unp->unp_conn->unp_addr;
    408 	} else {
    409 		if (unp->unp_addr)
    410 			sun = unp->unp_addr;
    411 	}
    412 	if (sun == NULL)
    413 		sun = &sun_noname;
    414 
    415 	memcpy(nam, sun, sun->sun_len);
    416 }
    417 
    418 static int
    419 unp_rcvd(struct socket *so, int flags, struct lwp *l)
    420 {
    421 	struct unpcb *unp = sotounpcb(so);
    422 	struct socket *so2;
    423 	u_int newhiwat;
    424 
    425 	KASSERT(solocked(so));
    426 	KASSERT(unp != NULL);
    427 
    428 	switch (so->so_type) {
    429 
    430 	case SOCK_DGRAM:
    431 		panic("uipc 1");
    432 		/*NOTREACHED*/
    433 
    434 	case SOCK_SEQPACKET: /* FALLTHROUGH */
    435 	case SOCK_STREAM:
    436 #define	rcv (&so->so_rcv)
    437 #define snd (&so2->so_snd)
    438 		if (unp->unp_conn == 0)
    439 			break;
    440 		so2 = unp->unp_conn->unp_socket;
    441 		KASSERT(solocked2(so, so2));
    442 		/*
    443 		 * Adjust backpressure on sender
    444 		 * and wakeup any waiting to write.
    445 		 */
    446 		snd->sb_mbmax += unp->unp_mbcnt - rcv->sb_mbcnt;
    447 		unp->unp_mbcnt = rcv->sb_mbcnt;
    448 		newhiwat = snd->sb_hiwat + unp->unp_cc - rcv->sb_cc;
    449 		(void)chgsbsize(so2->so_uidinfo,
    450 		    &snd->sb_hiwat, newhiwat, RLIM_INFINITY);
    451 		unp->unp_cc = rcv->sb_cc;
    452 		sowwakeup(so2);
    453 #undef snd
    454 #undef rcv
    455 		break;
    456 
    457 	default:
    458 		panic("uipc 2");
    459 	}
    460 
    461 	return 0;
    462 }
    463 
    464 static int
    465 unp_recvoob(struct socket *so, struct mbuf *m, int flags)
    466 {
    467 	KASSERT(solocked(so));
    468 
    469 	return SET_ERROR(EOPNOTSUPP);
    470 }
    471 
    472 static int
    473 unp_send(struct socket *so, struct mbuf *m, struct sockaddr *nam,
    474     struct mbuf *control, struct lwp *l)
    475 {
    476 	struct unpcb *unp = sotounpcb(so);
    477 	int error = 0;
    478 	u_int newhiwat;
    479 	struct socket *so2;
    480 
    481 	KASSERT(solocked(so));
    482 	KASSERT(unp != NULL);
    483 	KASSERT(m != NULL);
    484 
    485 	/*
    486 	 * Note: unp_internalize() rejects any control message
    487 	 * other than SCM_RIGHTS, and only allows one.  This
    488 	 * has the side-effect of preventing a caller from
    489 	 * forging SCM_CREDS.
    490 	 */
    491 	if (control) {
    492 		sounlock(so);
    493 		error = unp_internalize(&control);
    494 		solock(so);
    495 		if (error != 0) {
    496 			m_freem(control);
    497 			m_freem(m);
    498 			return error;
    499 		}
    500 	}
    501 
    502 	switch (so->so_type) {
    503 
    504 	case SOCK_DGRAM: {
    505 		KASSERT(so->so_lock == uipc_lock);
    506 		if (nam) {
    507 			if ((so->so_state & SS_ISCONNECTED) != 0)
    508 				error = SET_ERROR(EISCONN);
    509 			else {
    510 				/*
    511 				 * Note: once connected, the
    512 				 * socket's lock must not be
    513 				 * dropped until we have sent
    514 				 * the message and disconnected.
    515 				 * This is necessary to prevent
    516 				 * intervening control ops, like
    517 				 * another connection.
    518 				 */
    519 				error = unp_connect(so, nam, l);
    520 			}
    521 		} else {
    522 			if ((so->so_state & SS_ISCONNECTED) == 0)
    523 				error = SET_ERROR(ENOTCONN);
    524 		}
    525 		if (error) {
    526 			unp_dispose(control);
    527 			m_freem(control);
    528 			m_freem(m);
    529 			return error;
    530 		}
    531 		error = unp_output(m, control, unp);
    532 		if (nam)
    533 			unp_disconnect1(unp);
    534 		break;
    535 	}
    536 
    537 	case SOCK_SEQPACKET: /* FALLTHROUGH */
    538 	case SOCK_STREAM:
    539 #define	rcv (&so2->so_rcv)
    540 #define	snd (&so->so_snd)
    541 		if (unp->unp_conn == NULL) {
    542 			error = SET_ERROR(ENOTCONN);
    543 			break;
    544 		}
    545 		so2 = unp->unp_conn->unp_socket;
    546 		KASSERT(solocked2(so, so2));
    547 		if (unp->unp_conn->unp_flags & UNP_WANTCRED) {
    548 			/*
    549 			 * Credentials are passed only once on
    550 			 * SOCK_STREAM and SOCK_SEQPACKET.
    551 			 */
    552 			unp->unp_conn->unp_flags &= ~UNP_WANTCRED;
    553 			control = unp_addsockcred(l, control);
    554 		}
    555 		if (unp->unp_conn->unp_flags & UNP_OWANTCRED) {
    556 			/*
    557 			 * Credentials are passed only once on
    558 			 * SOCK_STREAM and SOCK_SEQPACKET.
    559 			 */
    560 			unp->unp_conn->unp_flags &= ~UNP_OWANTCRED;
    561 			MODULE_HOOK_CALL(uipc_unp_70_hook, (curlwp, control),
    562 			    stub_compat_70_unp_addsockcred(curlwp, control),
    563 			    control);
    564 		}
    565 		/*
    566 		 * Send to paired receive port, and then reduce
    567 		 * send buffer hiwater marks to maintain backpressure.
    568 		 * Wake up readers.
    569 		 */
    570 		if (control) {
    571 			sbappendcontrol(rcv, m, control);
    572 			control = NULL;
    573 		} else {
    574 			switch(so->so_type) {
    575 			case SOCK_SEQPACKET:
    576 				sbappendrecord(rcv, m);
    577 				break;
    578 			case SOCK_STREAM:
    579 				sbappend(rcv, m);
    580 				break;
    581 			default:
    582 				panic("uipc_usrreq");
    583 				break;
    584 			}
    585 		}
    586 		snd->sb_mbmax -=
    587 		    rcv->sb_mbcnt - unp->unp_conn->unp_mbcnt;
    588 		unp->unp_conn->unp_mbcnt = rcv->sb_mbcnt;
    589 		newhiwat = snd->sb_hiwat -
    590 		    (rcv->sb_cc - unp->unp_conn->unp_cc);
    591 		(void)chgsbsize(so->so_uidinfo,
    592 		    &snd->sb_hiwat, newhiwat, RLIM_INFINITY);
    593 		unp->unp_conn->unp_cc = rcv->sb_cc;
    594 		sorwakeup(so2);
    595 #undef snd
    596 #undef rcv
    597 		if (control != NULL) {
    598 			unp_dispose(control);
    599 			m_freem(control);
    600 		}
    601 		break;
    602 
    603 	default:
    604 		panic("uipc 4");
    605 	}
    606 
    607 	return error;
    608 }
    609 
    610 static int
    611 unp_sendoob(struct socket *so, struct mbuf *m, struct mbuf * control)
    612 {
    613 	KASSERT(solocked(so));
    614 
    615 	m_freem(m);
    616 	m_freem(control);
    617 
    618 	return SET_ERROR(EOPNOTSUPP);
    619 }
    620 
    621 /*
    622  * Unix domain socket option processing.
    623  */
    624 int
    625 uipc_ctloutput(int op, struct socket *so, struct sockopt *sopt)
    626 {
    627 	struct unpcb *unp = sotounpcb(so);
    628 	int optval = 0, error = 0;
    629 
    630 	KASSERT(solocked(so));
    631 
    632 	if (sopt->sopt_level != SOL_LOCAL) {
    633 		error = SET_ERROR(ENOPROTOOPT);
    634 	} else switch (op) {
    635 
    636 	case PRCO_SETOPT:
    637 		switch (sopt->sopt_name) {
    638 		case LOCAL_OCREDS:
    639 			if (!compat70_ocreds_valid)  {
    640 				error = SET_ERROR(ENOPROTOOPT);
    641 				break;
    642 			}
    643 			/* FALLTHROUGH */
    644 		case LOCAL_CREDS:
    645 		case LOCAL_CONNWAIT:
    646 			error = sockopt_getint(sopt, &optval);
    647 			if (error)
    648 				break;
    649 			switch (sopt->sopt_name) {
    650 #define	OPTSET(bit) \
    651 	if (optval) \
    652 		unp->unp_flags |= (bit); \
    653 	else \
    654 		unp->unp_flags &= ~(bit);
    655 
    656 			case LOCAL_CREDS:
    657 				OPTSET(UNP_WANTCRED);
    658 				break;
    659 			case LOCAL_CONNWAIT:
    660 				OPTSET(UNP_CONNWAIT);
    661 				break;
    662 			case LOCAL_OCREDS:
    663 				OPTSET(UNP_OWANTCRED);
    664 				break;
    665 			}
    666 			break;
    667 #undef OPTSET
    668 
    669 		default:
    670 			error = SET_ERROR(ENOPROTOOPT);
    671 			break;
    672 		}
    673 		break;
    674 
    675 	case PRCO_GETOPT:
    676 		sounlock(so);
    677 		switch (sopt->sopt_name) {
    678 		case LOCAL_PEEREID:
    679 			if (unp->unp_flags & UNP_EIDSVALID) {
    680 				error = sockopt_set(sopt, &unp->unp_connid,
    681 				    sizeof(unp->unp_connid));
    682 			} else {
    683 				error = SET_ERROR(EINVAL);
    684 			}
    685 			break;
    686 		case LOCAL_CREDS:
    687 #define	OPTBIT(bit)	(unp->unp_flags & (bit) ? 1 : 0)
    688 
    689 			optval = OPTBIT(UNP_WANTCRED);
    690 			error = sockopt_setint(sopt, optval);
    691 			break;
    692 		case LOCAL_OCREDS:
    693 			if (compat70_ocreds_valid) {
    694 				optval = OPTBIT(UNP_OWANTCRED);
    695 				error = sockopt_setint(sopt, optval);
    696 				break;
    697 			}
    698 #undef OPTBIT
    699 			/* FALLTHROUGH */
    700 		default:
    701 			error = SET_ERROR(ENOPROTOOPT);
    702 			break;
    703 		}
    704 		solock(so);
    705 		break;
    706 	}
    707 	return (error);
    708 }
    709 
    710 /*
    711  * Both send and receive buffers are allocated PIPSIZ bytes of buffering
    712  * for stream sockets, although the total for sender and receiver is
    713  * actually only PIPSIZ.
    714  * Datagram sockets really use the sendspace as the maximum datagram size,
    715  * and don't really want to reserve the sendspace.  Their recvspace should
    716  * be large enough for at least one max-size datagram plus address.
    717  */
    718 #ifndef PIPSIZ
    719 #define	PIPSIZ	8192
    720 #endif
    721 u_long	unpst_sendspace = PIPSIZ;
    722 u_long	unpst_recvspace = PIPSIZ;
    723 u_long	unpdg_sendspace = 2*1024;	/* really max datagram size */
    724 u_long	unpdg_recvspace = 16*1024;
    725 
    726 u_int	unp_rights;			/* files in flight */
    727 u_int	unp_rights_ratio = 2;		/* limit, fraction of maxfiles */
    728 
    729 static int
    730 unp_attach(struct socket *so, int proto)
    731 {
    732 	struct unpcb *unp = sotounpcb(so);
    733 	u_long sndspc, rcvspc;
    734 	int error;
    735 
    736 	KASSERT(unp == NULL);
    737 
    738 	switch (so->so_type) {
    739 	case SOCK_SEQPACKET:
    740 		/* FALLTHROUGH */
    741 	case SOCK_STREAM:
    742 		if (so->so_lock == NULL) {
    743 			so->so_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
    744 			solock(so);
    745 		}
    746 		sndspc = unpst_sendspace;
    747 		rcvspc = unpst_recvspace;
    748 		break;
    749 
    750 	case SOCK_DGRAM:
    751 		if (so->so_lock == NULL) {
    752 			mutex_obj_hold(uipc_lock);
    753 			so->so_lock = uipc_lock;
    754 			solock(so);
    755 		}
    756 		sndspc = unpdg_sendspace;
    757 		rcvspc = unpdg_recvspace;
    758 		break;
    759 
    760 	default:
    761 		panic("unp_attach");
    762 	}
    763 
    764 	if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
    765 		error = soreserve(so, sndspc, rcvspc);
    766 		if (error) {
    767 			return error;
    768 		}
    769 	}
    770 
    771 	unp = kmem_zalloc(sizeof(*unp), KM_SLEEP);
    772 	nanotime(&unp->unp_ctime);
    773 	unp->unp_socket = so;
    774 	so->so_pcb = unp;
    775 
    776 	KASSERT(solocked(so));
    777 	return 0;
    778 }
    779 
    780 static void
    781 unp_detach(struct socket *so)
    782 {
    783 	struct unpcb *unp;
    784 	vnode_t *vp;
    785 
    786 	unp = sotounpcb(so);
    787 	KASSERT(unp != NULL);
    788 	KASSERT(solocked(so));
    789  retry:
    790 	if ((vp = unp->unp_vnode) != NULL) {
    791 		sounlock(so);
    792 		/* Acquire v_interlock to protect against unp_connect(). */
    793 		/* XXXAD racy */
    794 		mutex_enter(vp->v_interlock);
    795 		vp->v_socket = NULL;
    796 		mutex_exit(vp->v_interlock);
    797 		vrele(vp);
    798 		solock(so);
    799 		unp->unp_vnode = NULL;
    800 	}
    801 	if (unp->unp_conn)
    802 		unp_disconnect1(unp);
    803 	while (unp->unp_refs) {
    804 		KASSERT(solocked2(so, unp->unp_refs->unp_socket));
    805 		if (unp_drop(unp->unp_refs, SET_ERROR(ECONNRESET))) {
    806 			solock(so);
    807 			goto retry;
    808 		}
    809 	}
    810 	soisdisconnected(so);
    811 	so->so_pcb = NULL;
    812 	if (unp_rights) {
    813 		/*
    814 		 * Normally the receive buffer is flushed later, in sofree,
    815 		 * but if our receive buffer holds references to files that
    816 		 * are now garbage, we will enqueue those file references to
    817 		 * the garbage collector and kick it into action.
    818 		 */
    819 		sorflush(so);
    820 		unp_free(unp);
    821 		unp_thread_kick();
    822 	} else
    823 		unp_free(unp);
    824 }
    825 
    826 static int
    827 unp_accept(struct socket *so, struct sockaddr *nam)
    828 {
    829 	struct unpcb *unp = sotounpcb(so);
    830 	struct socket *so2;
    831 
    832 	KASSERT(solocked(so));
    833 	KASSERT(nam != NULL);
    834 
    835 	/* XXX code review required to determine if unp can ever be NULL */
    836 	if (unp == NULL)
    837 		return SET_ERROR(EINVAL);
    838 
    839 	KASSERT(so->so_lock == uipc_lock);
    840 	/*
    841 	 * Mark the initiating STREAM socket as connected *ONLY*
    842 	 * after it's been accepted.  This prevents a client from
    843 	 * overrunning a server and receiving ECONNREFUSED.
    844 	 */
    845 	if (unp->unp_conn == NULL) {
    846 		/*
    847 		 * This will use the empty socket and will not
    848 		 * allocate.
    849 		 */
    850 		unp_setaddr(so, nam, true);
    851 		return 0;
    852 	}
    853 	so2 = unp->unp_conn->unp_socket;
    854 	if (so2->so_state & SS_ISCONNECTING) {
    855 		KASSERT(so->so_head == NULL || solocked2(so, so->so_head));
    856 		KASSERT(so->so_head == NULL || solocked2(so2, so->so_head));
    857 		soisconnected(so2);
    858 	}
    859 	/*
    860 	 * If the connection is fully established, break the
    861 	 * association with uipc_lock and give the connected
    862 	 * pair a separate lock to share.
    863 	 * There is a race here: sotounpcb(so2)->unp_streamlock
    864 	 * is not locked, so when changing so2->so_lock
    865 	 * another thread can grab it while so->so_lock is still
    866 	 * pointing to the (locked) uipc_lock.
    867 	 * this should be harmless, except that this makes
    868 	 * solocked2() and solocked() unreliable.
    869 	 * Another problem is that unp_setaddr() expects the
    870 	 * the socket locked. Grabbing sotounpcb(so2)->unp_streamlock
    871 	 * fixes both issues.
    872 	 */
    873 	mutex_enter(sotounpcb(so2)->unp_streamlock);
    874 	unp_setpeerlocks(so2, so);
    875 	/*
    876 	 * Only now return peer's address, as we may need to
    877 	 * block in order to allocate memory.
    878 	 *
    879 	 * XXX Minor race: connection can be broken while
    880 	 * lock is dropped in unp_setaddr().  We will return
    881 	 * error == 0 and sun_noname as the peer address.
    882 	 */
    883 	unp_setaddr(so, nam, true);
    884 	/* so_lock now points to unp_streamlock */
    885 	mutex_exit(so2->so_lock);
    886 	return 0;
    887 }
    888 
    889 static int
    890 unp_ioctl(struct socket *so, u_long cmd, void *nam, struct ifnet *ifp)
    891 {
    892 	return SET_ERROR(EOPNOTSUPP);
    893 }
    894 
    895 static int
    896 unp_stat(struct socket *so, struct stat *ub)
    897 {
    898 	struct unpcb *unp;
    899 	struct socket *so2;
    900 
    901 	KASSERT(solocked(so));
    902 
    903 	unp = sotounpcb(so);
    904 	if (unp == NULL)
    905 		return SET_ERROR(EINVAL);
    906 
    907 	ub->st_blksize = so->so_snd.sb_hiwat;
    908 	switch (so->so_type) {
    909 	case SOCK_SEQPACKET: /* FALLTHROUGH */
    910 	case SOCK_STREAM:
    911 		if (unp->unp_conn == 0)
    912 			break;
    913 
    914 		so2 = unp->unp_conn->unp_socket;
    915 		KASSERT(solocked2(so, so2));
    916 		ub->st_blksize += so2->so_rcv.sb_cc;
    917 		break;
    918 	default:
    919 		break;
    920 	}
    921 	ub->st_dev = NODEV;
    922 	if (unp->unp_ino == 0) {
    923 #ifdef __HAVE_ATOMIC64_OPS
    924 		unp->unp_ino = atomic_inc_64_nv(&unp_ino);
    925 #else
    926 		mutex_enter(&unp_ino.lock);
    927 		unp->unp_ino = ++unp_ino.num;
    928 		mutex_exit(&unp_ino.lock);
    929 #endif
    930 	}
    931 	ub->st_atimespec = ub->st_mtimespec = ub->st_ctimespec = unp->unp_ctime;
    932 	ub->st_ino = unp->unp_ino;
    933 	ub->st_uid = so->so_uidinfo->ui_uid;
    934 	ub->st_gid = so->so_egid;
    935 	return (0);
    936 }
    937 
    938 static int
    939 unp_peeraddr(struct socket *so, struct sockaddr *nam)
    940 {
    941 	KASSERT(solocked(so));
    942 	KASSERT(sotounpcb(so) != NULL);
    943 	KASSERT(nam != NULL);
    944 
    945 	unp_setaddr(so, nam, true);
    946 	return 0;
    947 }
    948 
    949 static int
    950 unp_sockaddr(struct socket *so, struct sockaddr *nam)
    951 {
    952 	KASSERT(solocked(so));
    953 	KASSERT(sotounpcb(so) != NULL);
    954 	KASSERT(nam != NULL);
    955 
    956 	unp_setaddr(so, nam, false);
    957 	return 0;
    958 }
    959 
    960 /*
    961  * we only need to perform this allocation until syscalls other than
    962  * bind are adjusted to use sockaddr_big.
    963  */
    964 static struct sockaddr_un *
    965 makeun_sb(struct sockaddr *nam, size_t *addrlen)
    966 {
    967 	struct sockaddr_un *sun;
    968 
    969 	*addrlen = nam->sa_len + 1;
    970 	sun = malloc(*addrlen, M_SONAME, M_WAITOK);
    971 	memcpy(sun, nam, nam->sa_len);
    972 	*(((char *)sun) + nam->sa_len) = '\0';
    973 	return sun;
    974 }
    975 
    976 static int
    977 unp_bind(struct socket *so, struct sockaddr *nam, struct lwp *l)
    978 {
    979 	struct sockaddr_un *sun;
    980 	struct unpcb *unp;
    981 	vnode_t *vp;
    982 	struct vattr vattr;
    983 	size_t addrlen;
    984 	int error;
    985 	struct pathbuf *pb;
    986 	struct nameidata nd;
    987 	proc_t *p;
    988 
    989 	unp = sotounpcb(so);
    990 
    991 	KASSERT(solocked(so));
    992 	KASSERT(unp != NULL);
    993 	KASSERT(nam != NULL);
    994 
    995 	if (unp->unp_vnode != NULL)
    996 		return SET_ERROR(EINVAL);
    997 	if ((unp->unp_flags & UNP_BUSY) != 0) {
    998 		/*
    999 		 * EALREADY may not be strictly accurate, but since this
   1000 		 * is a major application error it's hardly a big deal.
   1001 		 */
   1002 		return SET_ERROR(EALREADY);
   1003 	}
   1004 	unp->unp_flags |= UNP_BUSY;
   1005 	sounlock(so);
   1006 
   1007 	p = l->l_proc;
   1008 	sun = makeun_sb(nam, &addrlen);
   1009 
   1010 	pb = pathbuf_create(sun->sun_path);
   1011 	if (pb == NULL) {
   1012 		error = SET_ERROR(ENOMEM);
   1013 		goto bad;
   1014 	}
   1015 	NDINIT(&nd, CREATE, FOLLOW | LOCKPARENT | TRYEMULROOT, pb);
   1016 
   1017 /* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */
   1018 	if ((error = namei(&nd)) != 0) {
   1019 		pathbuf_destroy(pb);
   1020 		goto bad;
   1021 	}
   1022 	vp = nd.ni_vp;
   1023 	if (vp != NULL) {
   1024 		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
   1025 		if (nd.ni_dvp == vp)
   1026 			vrele(nd.ni_dvp);
   1027 		else
   1028 			vput(nd.ni_dvp);
   1029 		vrele(vp);
   1030 		pathbuf_destroy(pb);
   1031 		error = SET_ERROR(EADDRINUSE);
   1032 		goto bad;
   1033 	}
   1034 	vattr_null(&vattr);
   1035 	vattr.va_type = VSOCK;
   1036 	vattr.va_mode = ACCESSPERMS & ~(p->p_cwdi->cwdi_cmask);
   1037 	error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr);
   1038 	if (error) {
   1039 		vput(nd.ni_dvp);
   1040 		pathbuf_destroy(pb);
   1041 		goto bad;
   1042 	}
   1043 	vp = nd.ni_vp;
   1044 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
   1045 	solock(so);
   1046 	vp->v_socket = unp->unp_socket;
   1047 	unp->unp_vnode = vp;
   1048 	unp->unp_addrlen = addrlen;
   1049 	unp->unp_addr = sun;
   1050 	VOP_UNLOCK(vp);
   1051 	vput(nd.ni_dvp);
   1052 	unp->unp_flags &= ~UNP_BUSY;
   1053 	pathbuf_destroy(pb);
   1054 	return (0);
   1055 
   1056  bad:
   1057 	free(sun, M_SONAME);
   1058 	solock(so);
   1059 	unp->unp_flags &= ~UNP_BUSY;
   1060 	return (error);
   1061 }
   1062 
   1063 static int
   1064 unp_listen(struct socket *so, struct lwp *l)
   1065 {
   1066 	struct unpcb *unp = sotounpcb(so);
   1067 
   1068 	KASSERT(solocked(so));
   1069 	KASSERT(unp != NULL);
   1070 
   1071 	/*
   1072 	 * If the socket can accept a connection, it must be
   1073 	 * locked by uipc_lock.
   1074 	 */
   1075 	unp_resetlock(so);
   1076 	if (unp->unp_vnode == NULL)
   1077 		return SET_ERROR(EINVAL);
   1078 
   1079 	unp_connid(l, unp, UNP_EIDSBIND);
   1080 	return 0;
   1081 }
   1082 
   1083 static int
   1084 unp_disconnect(struct socket *so)
   1085 {
   1086 	KASSERT(solocked(so));
   1087 	KASSERT(sotounpcb(so) != NULL);
   1088 
   1089 	unp_disconnect1(sotounpcb(so));
   1090 	return 0;
   1091 }
   1092 
   1093 static int
   1094 unp_shutdown(struct socket *so)
   1095 {
   1096 	KASSERT(solocked(so));
   1097 	KASSERT(sotounpcb(so) != NULL);
   1098 
   1099 	socantsendmore(so);
   1100 	unp_shutdown1(sotounpcb(so));
   1101 	return 0;
   1102 }
   1103 
   1104 static int
   1105 unp_abort(struct socket *so)
   1106 {
   1107 	KASSERT(solocked(so));
   1108 	KASSERT(sotounpcb(so) != NULL);
   1109 
   1110 	(void)unp_drop(sotounpcb(so), SET_ERROR(ECONNABORTED));
   1111 	KASSERT(so->so_head == NULL);
   1112 	KASSERT(so->so_pcb != NULL);
   1113 	unp_detach(so);
   1114 	return 0;
   1115 }
   1116 
   1117 static int
   1118 unp_connect1(struct socket *so, struct socket *so2, struct lwp *l)
   1119 {
   1120 	struct unpcb *unp = sotounpcb(so);
   1121 	struct unpcb *unp2;
   1122 
   1123 	if (so2->so_type != so->so_type)
   1124 		return SET_ERROR(EPROTOTYPE);
   1125 
   1126 	/*
   1127 	 * All three sockets involved must be locked by same lock:
   1128 	 *
   1129 	 * local endpoint (so)
   1130 	 * remote endpoint (so2)
   1131 	 * queue head (so2->so_head, only if PR_CONNREQUIRED)
   1132 	 */
   1133 	KASSERT(solocked2(so, so2));
   1134 	KASSERT(so->so_head == NULL);
   1135 	if (so2->so_head != NULL) {
   1136 		KASSERT(so2->so_lock == uipc_lock);
   1137 		KASSERT(solocked2(so2, so2->so_head));
   1138 	}
   1139 
   1140 	unp2 = sotounpcb(so2);
   1141 	unp->unp_conn = unp2;
   1142 
   1143 	switch (so->so_type) {
   1144 
   1145 	case SOCK_DGRAM:
   1146 		unp->unp_nextref = unp2->unp_refs;
   1147 		unp2->unp_refs = unp;
   1148 		soisconnected(so);
   1149 		break;
   1150 
   1151 	case SOCK_SEQPACKET: /* FALLTHROUGH */
   1152 	case SOCK_STREAM:
   1153 
   1154 		/*
   1155 		 * SOCK_SEQPACKET and SOCK_STREAM cases are handled by callers
   1156 		 * which are unp_connect() or unp_connect2().
   1157 		 */
   1158 
   1159 		break;
   1160 
   1161 	default:
   1162 		panic("unp_connect1");
   1163 	}
   1164 
   1165 	return 0;
   1166 }
   1167 
   1168 int
   1169 unp_connect(struct socket *so, struct sockaddr *nam, struct lwp *l)
   1170 {
   1171 	struct sockaddr_un *sun;
   1172 	vnode_t *vp;
   1173 	struct socket *so2, *so3;
   1174 	struct unpcb *unp, *unp2, *unp3;
   1175 	size_t addrlen;
   1176 	int error;
   1177 	struct pathbuf *pb;
   1178 	struct nameidata nd;
   1179 
   1180 	unp = sotounpcb(so);
   1181 	if ((unp->unp_flags & UNP_BUSY) != 0) {
   1182 		/*
   1183 		 * EALREADY may not be strictly accurate, but since this
   1184 		 * is a major application error it's hardly a big deal.
   1185 		 */
   1186 		return SET_ERROR(EALREADY);
   1187 	}
   1188 	unp->unp_flags |= UNP_BUSY;
   1189 	sounlock(so);
   1190 
   1191 	sun = makeun_sb(nam, &addrlen);
   1192 	pb = pathbuf_create(sun->sun_path);
   1193 	if (pb == NULL) {
   1194 		error = SET_ERROR(ENOMEM);
   1195 		goto bad2;
   1196 	}
   1197 
   1198 	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | TRYEMULROOT, pb);
   1199 
   1200 	if ((error = namei(&nd)) != 0) {
   1201 		pathbuf_destroy(pb);
   1202 		goto bad2;
   1203 	}
   1204 	vp = nd.ni_vp;
   1205 	pathbuf_destroy(pb);
   1206 	if (vp->v_type != VSOCK) {
   1207 		error = SET_ERROR(ENOTSOCK);
   1208 		goto bad;
   1209 	}
   1210 	if ((error = VOP_ACCESS(vp, VWRITE, l->l_cred)) != 0)
   1211 		goto bad;
   1212 	/* Acquire v_interlock to protect against unp_detach(). */
   1213 	mutex_enter(vp->v_interlock);
   1214 	so2 = vp->v_socket;
   1215 	if (so2 == NULL) {
   1216 		mutex_exit(vp->v_interlock);
   1217 		error = SET_ERROR(ECONNREFUSED);
   1218 		goto bad;
   1219 	}
   1220 	if (so->so_type != so2->so_type) {
   1221 		mutex_exit(vp->v_interlock);
   1222 		error = SET_ERROR(EPROTOTYPE);
   1223 		goto bad;
   1224 	}
   1225 	solock(so);
   1226 	unp_resetlock(so);
   1227 	mutex_exit(vp->v_interlock);
   1228 	if ((so->so_proto->pr_flags & PR_CONNREQUIRED) != 0) {
   1229 		/*
   1230 		 * This may seem somewhat fragile but is OK: if we can
   1231 		 * see SO_ACCEPTCONN set on the endpoint, then it must
   1232 		 * be locked by the domain-wide uipc_lock.
   1233 		 */
   1234 		KASSERT((so2->so_options & SO_ACCEPTCONN) == 0 ||
   1235 		    so2->so_lock == uipc_lock);
   1236 		if ((so2->so_options & SO_ACCEPTCONN) == 0 ||
   1237 		    (so3 = sonewconn(so2, false)) == NULL) {
   1238 			error = SET_ERROR(ECONNREFUSED);
   1239 			sounlock(so);
   1240 			goto bad;
   1241 		}
   1242 		unp2 = sotounpcb(so2);
   1243 		unp3 = sotounpcb(so3);
   1244 		if (unp2->unp_addr) {
   1245 			unp3->unp_addr = malloc(unp2->unp_addrlen,
   1246 			    M_SONAME, M_WAITOK);
   1247 			memcpy(unp3->unp_addr, unp2->unp_addr,
   1248 			    unp2->unp_addrlen);
   1249 			unp3->unp_addrlen = unp2->unp_addrlen;
   1250 		}
   1251 		unp3->unp_flags = unp2->unp_flags;
   1252 		so2 = so3;
   1253 		/*
   1254 		 * The connector's (client's) credentials are copied from its
   1255 		 * process structure at the time of connect() (which is now).
   1256 		 */
   1257 		unp_connid(l, unp3, UNP_EIDSVALID);
   1258 		 /*
   1259 		  * The receiver's (server's) credentials are copied from the
   1260 		  * unp_peercred member of socket on which the former called
   1261 		  * listen(); unp_listen() cached that process's credentials
   1262 		  * at that time so we can use them now.
   1263 		  */
   1264 		if (unp2->unp_flags & UNP_EIDSBIND) {
   1265 			memcpy(&unp->unp_connid, &unp2->unp_connid,
   1266 			    sizeof(unp->unp_connid));
   1267 			unp->unp_flags |= UNP_EIDSVALID;
   1268 		}
   1269 	}
   1270 	error = unp_connect1(so, so2, l);
   1271 	if (error) {
   1272 		sounlock(so);
   1273 		goto bad;
   1274 	}
   1275 	unp2 = sotounpcb(so2);
   1276 	switch (so->so_type) {
   1277 
   1278 	/*
   1279 	 * SOCK_DGRAM and default cases are handled in prior call to
   1280 	 * unp_connect1(), do not add a default case without fixing
   1281 	 * unp_connect1().
   1282 	 */
   1283 
   1284 	case SOCK_SEQPACKET: /* FALLTHROUGH */
   1285 	case SOCK_STREAM:
   1286 		unp2->unp_conn = unp;
   1287 		if ((unp->unp_flags | unp2->unp_flags) & UNP_CONNWAIT)
   1288 			soisconnecting(so);
   1289 		else
   1290 			soisconnected(so);
   1291 		soisconnected(so2);
   1292 		/*
   1293 		 * If the connection is fully established, break the
   1294 		 * association with uipc_lock and give the connected
   1295 		 * pair a separate lock to share.
   1296 		 */
   1297 		KASSERT(so2->so_head != NULL);
   1298 		unp_setpeerlocks(so, so2);
   1299 		break;
   1300 
   1301 	}
   1302 	sounlock(so);
   1303  bad:
   1304 	vput(vp);
   1305  bad2:
   1306 	free(sun, M_SONAME);
   1307 	solock(so);
   1308 	unp->unp_flags &= ~UNP_BUSY;
   1309 	return (error);
   1310 }
   1311 
   1312 int
   1313 unp_connect2(struct socket *so, struct socket *so2)
   1314 {
   1315 	struct unpcb *unp = sotounpcb(so);
   1316 	struct unpcb *unp2;
   1317 	int error = 0;
   1318 
   1319 	KASSERT(solocked2(so, so2));
   1320 
   1321 	error = unp_connect1(so, so2, curlwp);
   1322 	if (error)
   1323 		return error;
   1324 
   1325 	unp2 = sotounpcb(so2);
   1326 	switch (so->so_type) {
   1327 
   1328 	/*
   1329 	 * SOCK_DGRAM and default cases are handled in prior call to
   1330 	 * unp_connect1(), do not add a default case without fixing
   1331 	 * unp_connect1().
   1332 	 */
   1333 
   1334 	case SOCK_SEQPACKET: /* FALLTHROUGH */
   1335 	case SOCK_STREAM:
   1336 		unp2->unp_conn = unp;
   1337 		soisconnected(so);
   1338 		soisconnected(so2);
   1339 		break;
   1340 
   1341 	}
   1342 	return error;
   1343 }
   1344 
   1345 static void
   1346 unp_disconnect1(struct unpcb *unp)
   1347 {
   1348 	struct unpcb *unp2 = unp->unp_conn;
   1349 	struct socket *so;
   1350 
   1351 	if (unp2 == 0)
   1352 		return;
   1353 	unp->unp_conn = 0;
   1354 	so = unp->unp_socket;
   1355 	switch (so->so_type) {
   1356 	case SOCK_DGRAM:
   1357 		if (unp2->unp_refs == unp)
   1358 			unp2->unp_refs = unp->unp_nextref;
   1359 		else {
   1360 			unp2 = unp2->unp_refs;
   1361 			for (;;) {
   1362 				KASSERT(solocked2(so, unp2->unp_socket));
   1363 				if (unp2 == 0)
   1364 					panic("unp_disconnect1");
   1365 				if (unp2->unp_nextref == unp)
   1366 					break;
   1367 				unp2 = unp2->unp_nextref;
   1368 			}
   1369 			unp2->unp_nextref = unp->unp_nextref;
   1370 		}
   1371 		unp->unp_nextref = 0;
   1372 		so->so_state &= ~SS_ISCONNECTED;
   1373 		break;
   1374 
   1375 	case SOCK_SEQPACKET: /* FALLTHROUGH */
   1376 	case SOCK_STREAM:
   1377 		KASSERT(solocked2(so, unp2->unp_socket));
   1378 		soisdisconnected(so);
   1379 		unp2->unp_conn = 0;
   1380 		soisdisconnected(unp2->unp_socket);
   1381 		break;
   1382 	}
   1383 }
   1384 
   1385 static void
   1386 unp_shutdown1(struct unpcb *unp)
   1387 {
   1388 	struct socket *so;
   1389 
   1390 	switch(unp->unp_socket->so_type) {
   1391 	case SOCK_SEQPACKET: /* FALLTHROUGH */
   1392 	case SOCK_STREAM:
   1393 		if (unp->unp_conn && (so = unp->unp_conn->unp_socket))
   1394 			socantrcvmore(so);
   1395 		break;
   1396 	default:
   1397 		break;
   1398 	}
   1399 }
   1400 
   1401 static bool
   1402 unp_drop(struct unpcb *unp, int errno)
   1403 {
   1404 	struct socket *so = unp->unp_socket;
   1405 
   1406 	KASSERT(solocked(so));
   1407 
   1408 	so->so_error = errno;
   1409 	unp_disconnect1(unp);
   1410 	if (so->so_head) {
   1411 		so->so_pcb = NULL;
   1412 		/* sofree() drops the socket lock */
   1413 		sofree(so);
   1414 		unp_free(unp);
   1415 		return true;
   1416 	}
   1417 	return false;
   1418 }
   1419 
   1420 #ifdef notdef
   1421 unp_drain(void)
   1422 {
   1423 
   1424 }
   1425 #endif
   1426 
   1427 int
   1428 unp_externalize(struct mbuf *rights, struct lwp *l, int flags)
   1429 {
   1430 	struct cmsghdr * const cm = mtod(rights, struct cmsghdr *);
   1431 	struct proc * const p = l->l_proc;
   1432 	file_t **rp;
   1433 	int error = 0;
   1434 
   1435 	const size_t nfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm))) /
   1436 	    sizeof(file_t *);
   1437 	if (nfds == 0)
   1438 		goto noop;
   1439 
   1440 	int * const fdp = kmem_alloc(nfds * sizeof(int), KM_SLEEP);
   1441 	rw_enter(&p->p_cwdi->cwdi_lock, RW_READER);
   1442 
   1443 	/* Make sure the recipient should be able to see the files.. */
   1444 	rp = (file_t **)CMSG_DATA(cm);
   1445 	for (size_t i = 0; i < nfds; i++) {
   1446 		file_t * const fp = *rp++;
   1447 		if (fp == NULL) {
   1448 			error = SET_ERROR(EINVAL);
   1449 			goto out;
   1450 		}
   1451 		/*
   1452 		 * If we are in a chroot'ed directory, and
   1453 		 * someone wants to pass us a directory, make
   1454 		 * sure it's inside the subtree we're allowed
   1455 		 * to access.
   1456 		 */
   1457 		if (p->p_cwdi->cwdi_rdir != NULL && fp->f_type == DTYPE_VNODE) {
   1458 			vnode_t *vp = fp->f_vnode;
   1459 			if ((vp->v_type == VDIR) &&
   1460 			    !vn_isunder(vp, p->p_cwdi->cwdi_rdir, l)) {
   1461 				error = SET_ERROR(EPERM);
   1462 				goto out;
   1463 			}
   1464 		}
   1465 	}
   1466 
   1467  restart:
   1468 	/*
   1469 	 * First loop -- allocate file descriptor table slots for the
   1470 	 * new files.
   1471 	 */
   1472 	for (size_t i = 0; i < nfds; i++) {
   1473 		if ((error = fd_alloc(p, 0, &fdp[i])) != 0) {
   1474 			/*
   1475 			 * Back out what we've done so far.
   1476 			 */
   1477 			while (i-- > 0) {
   1478 				fd_abort(p, NULL, fdp[i]);
   1479 			}
   1480 			if (error == ENOSPC) {
   1481 				fd_tryexpand(p);
   1482 				error = 0;
   1483 				goto restart;
   1484 			}
   1485 			/*
   1486 			 * This is the error that has historically
   1487 			 * been returned, and some callers may
   1488 			 * expect it.
   1489 			 */
   1490 			error = SET_ERROR(EMSGSIZE);
   1491 			goto out;
   1492 		}
   1493 	}
   1494 
   1495 	/*
   1496 	 * Now that adding them has succeeded, update all of the
   1497 	 * file passing state and affix the descriptors.
   1498 	 */
   1499 	rp = (file_t **)CMSG_DATA(cm);
   1500 	int *ofdp = (int *)CMSG_DATA(cm);
   1501 	for (size_t i = 0; i < nfds; i++) {
   1502 		file_t * const fp = *rp++;
   1503 		const int fd = fdp[i];
   1504 		atomic_dec_uint(&unp_rights);
   1505 		fd_set_exclose(l, fd, (flags & O_CLOEXEC) != 0);
   1506 		fd_set_foclose(l, fd, (flags & O_CLOFORK) != 0);
   1507 		fd_affix(p, fp, fd);
   1508 		/*
   1509 		 * Done with this file pointer, replace it with a fd;
   1510 		 */
   1511 		*ofdp++ = fd;
   1512 		mutex_enter(&fp->f_lock);
   1513 		fp->f_msgcount--;
   1514 		mutex_exit(&fp->f_lock);
   1515 		/*
   1516 		 * Note that fd_affix() adds a reference to the file.
   1517 		 * The file may already have been closed by another
   1518 		 * LWP in the process, so we must drop the reference
   1519 		 * added by unp_internalize() with closef().
   1520 		 */
   1521 		closef(fp);
   1522 	}
   1523 
   1524 	/*
   1525 	 * Adjust length, in case of transition from large file_t
   1526 	 * pointers to ints.
   1527 	 */
   1528 	if (sizeof(file_t *) != sizeof(int)) {
   1529 		cm->cmsg_len = CMSG_LEN(nfds * sizeof(int));
   1530 		rights->m_len = CMSG_SPACE(nfds * sizeof(int));
   1531 	}
   1532  out:
   1533 	if (__predict_false(error != 0)) {
   1534 		file_t **const fpp = (file_t **)CMSG_DATA(cm);
   1535 		for (size_t i = 0; i < nfds; i++)
   1536 			unp_discard_now(fpp[i]);
   1537 		/*
   1538 		 * Truncate the array so that nobody will try to interpret
   1539 		 * what is now garbage in it.
   1540 		 */
   1541 		cm->cmsg_len = CMSG_LEN(0);
   1542 		rights->m_len = CMSG_SPACE(0);
   1543 	}
   1544 	rw_exit(&p->p_cwdi->cwdi_lock);
   1545 	kmem_free(fdp, nfds * sizeof(int));
   1546 
   1547  noop:
   1548 	/*
   1549 	 * Don't disclose kernel memory in the alignment space.
   1550 	 */
   1551 	KASSERT(cm->cmsg_len <= rights->m_len);
   1552 	memset(&mtod(rights, char *)[cm->cmsg_len], 0, rights->m_len -
   1553 	    cm->cmsg_len);
   1554 	return error;
   1555 }
   1556 
   1557 static int
   1558 unp_internalize(struct mbuf **controlp)
   1559 {
   1560 	filedesc_t *fdescp = curlwp->l_fd;
   1561 	fdtab_t *dt;
   1562 	struct mbuf *control = *controlp;
   1563 	struct cmsghdr *newcm, *cm = mtod(control, struct cmsghdr *);
   1564 	file_t **rp, **files;
   1565 	file_t *fp;
   1566 	int i, fd, *fdp;
   1567 	int nfds, error;
   1568 	u_int maxmsg;
   1569 
   1570 	error = 0;
   1571 	newcm = NULL;
   1572 
   1573 	/* Sanity check the control message header. */
   1574 	if (cm->cmsg_type != SCM_RIGHTS || cm->cmsg_level != SOL_SOCKET ||
   1575 	    cm->cmsg_len > control->m_len ||
   1576 	    cm->cmsg_len < CMSG_ALIGN(sizeof(*cm)))
   1577 		return SET_ERROR(EINVAL);
   1578 
   1579 	/*
   1580 	 * Verify that the file descriptors are valid, and acquire
   1581 	 * a reference to each.
   1582 	 */
   1583 	nfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm))) / sizeof(int);
   1584 	fdp = (int *)CMSG_DATA(cm);
   1585 	maxmsg = maxfiles / unp_rights_ratio;
   1586 	for (i = 0; i < nfds; i++) {
   1587 		fd = *fdp++;
   1588 		if (atomic_inc_uint_nv(&unp_rights) > maxmsg) {
   1589 			atomic_dec_uint(&unp_rights);
   1590 			nfds = i;
   1591 			error = SET_ERROR(EAGAIN);
   1592 			goto out;
   1593 		}
   1594 		if ((fp = fd_getfile(fd)) == NULL
   1595 		    || fp->f_type == DTYPE_KQUEUE) {
   1596 			if (fp)
   1597 				fd_putfile(fd);
   1598 			atomic_dec_uint(&unp_rights);
   1599 			nfds = i;
   1600 			error = SET_ERROR(EBADF);
   1601 			goto out;
   1602 		}
   1603 	}
   1604 
   1605 	/* Allocate new space and copy header into it. */
   1606 	newcm = malloc(CMSG_SPACE(nfds * sizeof(file_t *)), M_MBUF, M_WAITOK);
   1607 	if (newcm == NULL) {
   1608 		error = SET_ERROR(E2BIG);
   1609 		goto out;
   1610 	}
   1611 	memcpy(newcm, cm, sizeof(struct cmsghdr));
   1612 	memset(newcm + 1, 0, CMSG_LEN(0) - sizeof(struct cmsghdr));
   1613 	files = (file_t **)CMSG_DATA(newcm);
   1614 
   1615 	/*
   1616 	 * Transform the file descriptors into file_t pointers, in
   1617 	 * reverse order so that if pointers are bigger than ints, the
   1618 	 * int won't get until we're done.  No need to lock, as we have
   1619 	 * already validated the descriptors with fd_getfile().
   1620 	 */
   1621 	fdp = (int *)CMSG_DATA(cm) + nfds;
   1622 	rp = files + nfds;
   1623 	for (i = 0; i < nfds; i++) {
   1624 		dt = atomic_load_consume(&fdescp->fd_dt);
   1625 		fp = atomic_load_consume(&dt->dt_ff[*--fdp]->ff_file);
   1626 		KASSERT(fp != NULL);
   1627 		mutex_enter(&fp->f_lock);
   1628 		*--rp = fp;
   1629 		fp->f_count++;
   1630 		fp->f_msgcount++;
   1631 		mutex_exit(&fp->f_lock);
   1632 	}
   1633 
   1634  out:
   1635 	/* Release descriptor references. */
   1636 	fdp = (int *)CMSG_DATA(cm);
   1637 	for (i = 0; i < nfds; i++) {
   1638 		fd_putfile(*fdp++);
   1639 		if (error != 0) {
   1640 			atomic_dec_uint(&unp_rights);
   1641 		}
   1642 	}
   1643 
   1644 	if (error == 0) {
   1645 		if (control->m_flags & M_EXT) {
   1646 			m_freem(control);
   1647 			*controlp = control = m_get(M_WAIT, MT_CONTROL);
   1648 		}
   1649 		MEXTADD(control, newcm, CMSG_SPACE(nfds * sizeof(file_t *)),
   1650 		    M_MBUF, NULL, NULL);
   1651 		cm = newcm;
   1652 		/*
   1653 		 * Adjust message & mbuf to note amount of space
   1654 		 * actually used.
   1655 		 */
   1656 		cm->cmsg_len = CMSG_LEN(nfds * sizeof(file_t *));
   1657 		control->m_len = CMSG_SPACE(nfds * sizeof(file_t *));
   1658 	}
   1659 
   1660 	return error;
   1661 }
   1662 
   1663 struct mbuf *
   1664 unp_addsockcred(struct lwp *l, struct mbuf *control)
   1665 {
   1666 	struct sockcred *sc;
   1667 	struct mbuf *m;
   1668 	void *p;
   1669 
   1670 	m = sbcreatecontrol1(&p, SOCKCREDSIZE(kauth_cred_ngroups(l->l_cred)),
   1671 		SCM_CREDS, SOL_SOCKET, M_WAITOK);
   1672 	if (m == NULL)
   1673 		return control;
   1674 
   1675 	sc = p;
   1676 	sc->sc_pid = l->l_proc->p_pid;
   1677 	sc->sc_uid = kauth_cred_getuid(l->l_cred);
   1678 	sc->sc_euid = kauth_cred_geteuid(l->l_cred);
   1679 	sc->sc_gid = kauth_cred_getgid(l->l_cred);
   1680 	sc->sc_egid = kauth_cred_getegid(l->l_cred);
   1681 	sc->sc_ngroups = kauth_cred_ngroups(l->l_cred);
   1682 
   1683 	for (int i = 0; i < sc->sc_ngroups; i++)
   1684 		sc->sc_groups[i] = kauth_cred_group(l->l_cred, i);
   1685 
   1686 	return m_add(control, m);
   1687 }
   1688 
   1689 /*
   1690  * Do a mark-sweep GC of files in the system, to free up any which are
   1691  * caught in flight to an about-to-be-closed socket.  Additionally,
   1692  * process deferred file closures.
   1693  */
   1694 static void
   1695 unp_gc(file_t *dp)
   1696 {
   1697 	extern	struct domain unixdomain;
   1698 	file_t *fp, *np;
   1699 	struct socket *so, *so1;
   1700 	u_int i, oflags, rflags;
   1701 	bool didwork;
   1702 
   1703 	KASSERT(curlwp == unp_thread_lwp);
   1704 	KASSERT(mutex_owned(&filelist_lock));
   1705 
   1706 	/*
   1707 	 * First, process deferred file closures.
   1708 	 */
   1709 	while (!SLIST_EMPTY(&unp_thread_discard)) {
   1710 		fp = SLIST_FIRST(&unp_thread_discard);
   1711 		KASSERT(fp->f_unpcount > 0);
   1712 		KASSERT(fp->f_count > 0);
   1713 		KASSERT(fp->f_msgcount > 0);
   1714 		KASSERT(fp->f_count >= fp->f_unpcount);
   1715 		KASSERT(fp->f_count >= fp->f_msgcount);
   1716 		KASSERT(fp->f_msgcount >= fp->f_unpcount);
   1717 		SLIST_REMOVE_HEAD(&unp_thread_discard, f_unplist);
   1718 		i = fp->f_unpcount;
   1719 		fp->f_unpcount = 0;
   1720 		mutex_exit(&filelist_lock);
   1721 		for (; i != 0; i--) {
   1722 			unp_discard_now(fp);
   1723 		}
   1724 		mutex_enter(&filelist_lock);
   1725 	}
   1726 
   1727 	/*
   1728 	 * Clear mark bits.  Ensure that we don't consider new files
   1729 	 * entering the file table during this loop (they will not have
   1730 	 * FSCAN set).
   1731 	 */
   1732 	unp_defer = 0;
   1733 	LIST_FOREACH(fp, &filehead, f_list) {
   1734 		for (oflags = fp->f_flag;; oflags = rflags) {
   1735 			rflags = atomic_cas_uint(&fp->f_flag, oflags,
   1736 			    (oflags | FSCAN) & ~(FMARK|FDEFER));
   1737 			if (__predict_true(oflags == rflags)) {
   1738 				break;
   1739 			}
   1740 		}
   1741 	}
   1742 
   1743 	/*
   1744 	 * Iterate over the set of sockets, marking ones believed (based on
   1745 	 * refcount) to be referenced from a process, and marking for rescan
   1746 	 * sockets which are queued on a socket.  Recan continues descending
   1747 	 * and searching for sockets referenced by sockets (FDEFER), until
   1748 	 * there are no more socket->socket references to be discovered.
   1749 	 */
   1750 	do {
   1751 		didwork = false;
   1752 		for (fp = LIST_FIRST(&filehead); fp != NULL; fp = np) {
   1753 			KASSERT(mutex_owned(&filelist_lock));
   1754 			np = LIST_NEXT(fp, f_list);
   1755 			mutex_enter(&fp->f_lock);
   1756 			if ((fp->f_flag & FDEFER) != 0) {
   1757 				atomic_and_uint(&fp->f_flag, ~FDEFER);
   1758 				unp_defer--;
   1759 				if (fp->f_count == 0) {
   1760 					/*
   1761 					 * XXX: closef() doesn't pay attention
   1762 					 * to FDEFER
   1763 					 */
   1764 					mutex_exit(&fp->f_lock);
   1765 					continue;
   1766 				}
   1767 			} else {
   1768 				if (fp->f_count == 0 ||
   1769 				    (fp->f_flag & FMARK) != 0 ||
   1770 				    fp->f_count == fp->f_msgcount ||
   1771 				    fp->f_unpcount != 0) {
   1772 					mutex_exit(&fp->f_lock);
   1773 					continue;
   1774 				}
   1775 			}
   1776 			atomic_or_uint(&fp->f_flag, FMARK);
   1777 
   1778 			if (fp->f_type != DTYPE_SOCKET ||
   1779 			    (so = fp->f_socket) == NULL ||
   1780 			    so->so_proto->pr_domain != &unixdomain ||
   1781 			    (so->so_proto->pr_flags & PR_RIGHTS) == 0) {
   1782 				mutex_exit(&fp->f_lock);
   1783 				continue;
   1784 			}
   1785 
   1786 			/* Gain file ref, mark our position, and unlock. */
   1787 			didwork = true;
   1788 			LIST_INSERT_AFTER(fp, dp, f_list);
   1789 			fp->f_count++;
   1790 			mutex_exit(&fp->f_lock);
   1791 			mutex_exit(&filelist_lock);
   1792 
   1793 			/*
   1794 			 * Mark files referenced from sockets queued on the
   1795 			 * accept queue as well.
   1796 			 */
   1797 			solock(so);
   1798 			unp_scan(so->so_rcv.sb_mb, unp_mark, 0);
   1799 			if ((so->so_options & SO_ACCEPTCONN) != 0) {
   1800 				TAILQ_FOREACH(so1, &so->so_q0, so_qe) {
   1801 					unp_scan(so1->so_rcv.sb_mb, unp_mark, 0);
   1802 				}
   1803 				TAILQ_FOREACH(so1, &so->so_q, so_qe) {
   1804 					unp_scan(so1->so_rcv.sb_mb, unp_mark, 0);
   1805 				}
   1806 			}
   1807 			sounlock(so);
   1808 
   1809 			/* Re-lock and restart from where we left off. */
   1810 			closef(fp);
   1811 			mutex_enter(&filelist_lock);
   1812 			np = LIST_NEXT(dp, f_list);
   1813 			LIST_REMOVE(dp, f_list);
   1814 		}
   1815 		/*
   1816 		 * Bail early if we did nothing in the loop above.  Could
   1817 		 * happen because of concurrent activity causing unp_defer
   1818 		 * to get out of sync.
   1819 		 */
   1820 	} while (unp_defer != 0 && didwork);
   1821 
   1822 	/*
   1823 	 * Sweep pass.
   1824 	 *
   1825 	 * We grab an extra reference to each of the files that are
   1826 	 * not otherwise accessible and then free the rights that are
   1827 	 * stored in messages on them.
   1828 	 */
   1829 	for (fp = LIST_FIRST(&filehead); fp != NULL; fp = np) {
   1830 		KASSERT(mutex_owned(&filelist_lock));
   1831 		np = LIST_NEXT(fp, f_list);
   1832 		mutex_enter(&fp->f_lock);
   1833 
   1834 		/*
   1835 		 * Ignore non-sockets.
   1836 		 * Ignore dead sockets, or sockets with pending close.
   1837 		 * Ignore sockets obviously referenced elsewhere.
   1838 		 * Ignore sockets marked as referenced by our scan.
   1839 		 * Ignore new sockets that did not exist during the scan.
   1840 		 */
   1841 		if (fp->f_type != DTYPE_SOCKET ||
   1842 		    fp->f_count == 0 || fp->f_unpcount != 0 ||
   1843 		    fp->f_count != fp->f_msgcount ||
   1844 		    (fp->f_flag & (FMARK | FSCAN)) != FSCAN) {
   1845 			mutex_exit(&fp->f_lock);
   1846 			continue;
   1847 		}
   1848 
   1849 		/* Gain file ref, mark our position, and unlock. */
   1850 		LIST_INSERT_AFTER(fp, dp, f_list);
   1851 		fp->f_count++;
   1852 		mutex_exit(&fp->f_lock);
   1853 		mutex_exit(&filelist_lock);
   1854 
   1855 		/*
   1856 		 * Flush all data from the socket's receive buffer.
   1857 		 * This will cause files referenced only by the
   1858 		 * socket to be queued for close.
   1859 		 */
   1860 		so = fp->f_socket;
   1861 		solock(so);
   1862 		sorflush(so);
   1863 		sounlock(so);
   1864 
   1865 		/* Re-lock and restart from where we left off. */
   1866 		closef(fp);
   1867 		mutex_enter(&filelist_lock);
   1868 		np = LIST_NEXT(dp, f_list);
   1869 		LIST_REMOVE(dp, f_list);
   1870 	}
   1871 }
   1872 
   1873 /*
   1874  * Garbage collector thread.  While SCM_RIGHTS messages are in transit,
   1875  * wake once per second to garbage collect.  Run continually while we
   1876  * have deferred closes to process.
   1877  */
   1878 static void
   1879 unp_thread(void *cookie)
   1880 {
   1881 	file_t *dp;
   1882 
   1883 	/* Allocate a dummy file for our scans. */
   1884 	if ((dp = fgetdummy()) == NULL) {
   1885 		panic("unp_thread");
   1886 	}
   1887 
   1888 	mutex_enter(&filelist_lock);
   1889 	for (;;) {
   1890 		KASSERT(mutex_owned(&filelist_lock));
   1891 		if (SLIST_EMPTY(&unp_thread_discard)) {
   1892 			if (unp_rights != 0) {
   1893 				(void)cv_timedwait(&unp_thread_cv,
   1894 				    &filelist_lock, hz);
   1895 			} else {
   1896 				cv_wait(&unp_thread_cv, &filelist_lock);
   1897 			}
   1898 		}
   1899 		unp_gc(dp);
   1900 	}
   1901 	/* NOTREACHED */
   1902 }
   1903 
   1904 /*
   1905  * Kick the garbage collector into action if there is something for
   1906  * it to process.
   1907  */
   1908 static void
   1909 unp_thread_kick(void)
   1910 {
   1911 
   1912 	if (!SLIST_EMPTY(&unp_thread_discard) || unp_rights != 0) {
   1913 		mutex_enter(&filelist_lock);
   1914 		cv_signal(&unp_thread_cv);
   1915 		mutex_exit(&filelist_lock);
   1916 	}
   1917 }
   1918 
   1919 void
   1920 unp_dispose(struct mbuf *m)
   1921 {
   1922 
   1923 	if (m)
   1924 		unp_scan(m, unp_discard_later, 1);
   1925 }
   1926 
   1927 void
   1928 unp_scan(struct mbuf *m0, void (*op)(file_t *), int discard)
   1929 {
   1930 	struct mbuf *m;
   1931 	file_t **rp, *fp;
   1932 	struct cmsghdr *cm;
   1933 	int i, qfds;
   1934 
   1935 	while (m0) {
   1936 		for (m = m0; m; m = m->m_next) {
   1937 			if (m->m_type != MT_CONTROL ||
   1938 			    m->m_len < sizeof(*cm)) {
   1939 				continue;
   1940 			}
   1941 			cm = mtod(m, struct cmsghdr *);
   1942 			if (cm->cmsg_level != SOL_SOCKET ||
   1943 			    cm->cmsg_type != SCM_RIGHTS)
   1944 				continue;
   1945 			qfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm)))
   1946 			    / sizeof(file_t *);
   1947 			rp = (file_t **)CMSG_DATA(cm);
   1948 			for (i = 0; i < qfds; i++) {
   1949 				fp = *rp;
   1950 				if (discard) {
   1951 					*rp = 0;
   1952 				}
   1953 				(*op)(fp);
   1954 				rp++;
   1955 			}
   1956 		}
   1957 		m0 = m0->m_nextpkt;
   1958 	}
   1959 }
   1960 
   1961 void
   1962 unp_mark(file_t *fp)
   1963 {
   1964 
   1965 	if (fp == NULL)
   1966 		return;
   1967 
   1968 	/* If we're already deferred, don't screw up the defer count */
   1969 	mutex_enter(&fp->f_lock);
   1970 	if (fp->f_flag & (FMARK | FDEFER)) {
   1971 		mutex_exit(&fp->f_lock);
   1972 		return;
   1973 	}
   1974 
   1975 	/*
   1976 	 * Minimize the number of deferrals...  Sockets are the only type of
   1977 	 * file which can hold references to another file, so just mark
   1978 	 * other files, and defer unmarked sockets for the next pass.
   1979 	 */
   1980 	if (fp->f_type == DTYPE_SOCKET) {
   1981 		unp_defer++;
   1982 		KASSERT(fp->f_count != 0);
   1983 		atomic_or_uint(&fp->f_flag, FDEFER);
   1984 	} else {
   1985 		atomic_or_uint(&fp->f_flag, FMARK);
   1986 	}
   1987 	mutex_exit(&fp->f_lock);
   1988 }
   1989 
   1990 static void
   1991 unp_discard_now(file_t *fp)
   1992 {
   1993 
   1994 	if (fp == NULL)
   1995 		return;
   1996 
   1997 	KASSERT(fp->f_count > 0);
   1998 	KASSERT(fp->f_msgcount > 0);
   1999 
   2000 	mutex_enter(&fp->f_lock);
   2001 	fp->f_msgcount--;
   2002 	mutex_exit(&fp->f_lock);
   2003 	atomic_dec_uint(&unp_rights);
   2004 	(void)closef(fp);
   2005 }
   2006 
   2007 static void
   2008 unp_discard_later(file_t *fp)
   2009 {
   2010 
   2011 	if (fp == NULL)
   2012 		return;
   2013 
   2014 	KASSERT(fp->f_count > 0);
   2015 	KASSERT(fp->f_msgcount > 0);
   2016 
   2017 	mutex_enter(&filelist_lock);
   2018 	if (fp->f_unpcount++ == 0) {
   2019 		SLIST_INSERT_HEAD(&unp_thread_discard, fp, f_unplist);
   2020 	}
   2021 	mutex_exit(&filelist_lock);
   2022 }
   2023 
   2024 static void
   2025 unp_sysctl_create(void)
   2026 {
   2027 
   2028 	KASSERT(usrreq_sysctllog == NULL);
   2029 	sysctl_createv(&usrreq_sysctllog, 0, NULL, NULL,
   2030 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2031 		       CTLTYPE_LONG, "sendspace",
   2032 		       SYSCTL_DESCR("Default stream send space"),
   2033 		       NULL, 0, &unpst_sendspace, 0,
   2034 		       CTL_NET, PF_LOCAL, SOCK_STREAM, CTL_CREATE, CTL_EOL);
   2035 	sysctl_createv(&usrreq_sysctllog, 0, NULL, NULL,
   2036 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2037 		       CTLTYPE_LONG, "recvspace",
   2038 		       SYSCTL_DESCR("Default stream recv space"),
   2039 		       NULL, 0, &unpst_recvspace, 0,
   2040 		       CTL_NET, PF_LOCAL, SOCK_STREAM, CTL_CREATE, CTL_EOL);
   2041 	sysctl_createv(&usrreq_sysctllog, 0, NULL, NULL,
   2042 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2043 		       CTLTYPE_LONG, "sendspace",
   2044 		       SYSCTL_DESCR("Default datagram send space"),
   2045 		       NULL, 0, &unpdg_sendspace, 0,
   2046 		       CTL_NET, PF_LOCAL, SOCK_DGRAM, CTL_CREATE, CTL_EOL);
   2047 	sysctl_createv(&usrreq_sysctllog, 0, NULL, NULL,
   2048 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2049 		       CTLTYPE_LONG, "recvspace",
   2050 		       SYSCTL_DESCR("Default datagram recv space"),
   2051 		       NULL, 0, &unpdg_recvspace, 0,
   2052 		       CTL_NET, PF_LOCAL, SOCK_DGRAM, CTL_CREATE, CTL_EOL);
   2053 	sysctl_createv(&usrreq_sysctllog, 0, NULL, NULL,
   2054 		       CTLFLAG_PERMANENT|CTLFLAG_READONLY,
   2055 		       CTLTYPE_INT, "inflight",
   2056 		       SYSCTL_DESCR("File descriptors in flight"),
   2057 		       NULL, 0, &unp_rights, 0,
   2058 		       CTL_NET, PF_LOCAL, CTL_CREATE, CTL_EOL);
   2059 	sysctl_createv(&usrreq_sysctllog, 0, NULL, NULL,
   2060 		       CTLFLAG_PERMANENT|CTLFLAG_READONLY,
   2061 		       CTLTYPE_INT, "deferred",
   2062 		       SYSCTL_DESCR("File descriptors deferred for close"),
   2063 		       NULL, 0, &unp_defer, 0,
   2064 		       CTL_NET, PF_LOCAL, CTL_CREATE, CTL_EOL);
   2065 }
   2066 
   2067 const struct pr_usrreqs unp_usrreqs = {
   2068 	.pr_attach	= unp_attach,
   2069 	.pr_detach	= unp_detach,
   2070 	.pr_accept	= unp_accept,
   2071 	.pr_bind	= unp_bind,
   2072 	.pr_listen	= unp_listen,
   2073 	.pr_connect	= unp_connect,
   2074 	.pr_connect2	= unp_connect2,
   2075 	.pr_disconnect	= unp_disconnect,
   2076 	.pr_shutdown	= unp_shutdown,
   2077 	.pr_abort	= unp_abort,
   2078 	.pr_ioctl	= unp_ioctl,
   2079 	.pr_stat	= unp_stat,
   2080 	.pr_peeraddr	= unp_peeraddr,
   2081 	.pr_sockaddr	= unp_sockaddr,
   2082 	.pr_rcvd	= unp_rcvd,
   2083 	.pr_recvoob	= unp_recvoob,
   2084 	.pr_send	= unp_send,
   2085 	.pr_sendoob	= unp_sendoob,
   2086 };
   2087