1 /*-
2 * Copyright (c) 1982, 1986, 1989, 1991, 1993
3 * The Regents of the University of California.
4 * Copyright (c) 2004-2007 Robert N. M. Watson
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 4. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * From: @(#)uipc_usrreq.c 8.3 (Berkeley) 1/4/94
32 */
33
34 /*
35 * UNIX Domain (Local) Sockets
36 *
37 * This is an implementation of UNIX (local) domain sockets. Each socket has
38 * an associated struct unpcb (UNIX protocol control block). Stream sockets
39 * may be connected to 0 or 1 other socket. Datagram sockets may be
40 * connected to 0, 1, or many other sockets. Sockets may be created and
41 * connected in pairs (socketpair(2)), or bound/connected to using the file
42 * system name space. For most purposes, only the receive socket buffer is
43 * used, as sending on one socket delivers directly to the receive socket
44 * buffer of a second socket.
45 *
46 * The implementation is substantially complicated by the fact that
47 * "ancillary data", such as file descriptors or credentials, may be passed
48 * across UNIX domain sockets. The potential for passing UNIX domain sockets
49 * over other UNIX domain sockets requires the implementation of a simple
50 * garbage collector to find and tear down cycles of disconnected sockets.
51 *
52 * TODO:
53 * SEQPACKET, RDM
54 * rethink name space problems
55 * need a proper out-of-band
56 * lock pushdown
57 */
58
59 #include <sys/cdefs.h>
60 __FBSDID("$FreeBSD$");
61
62 #include "opt_ddb.h"
63 #include "opt_mac.h"
64
65 #include <sys/param.h>
66 #include <sys/domain.h>
67 #include <sys/fcntl.h>
68 #include <sys/malloc.h> /* XXX must be before <sys/file.h> */
69 #include <sys/eventhandler.h>
70 #include <sys/file.h>
71 #include <sys/filedesc.h>
72 #include <sys/jail.h>
73 #include <sys/kernel.h>
74 #include <sys/lock.h>
75 #include <sys/mbuf.h>
76 #include <sys/mount.h>
77 #include <sys/mutex.h>
78 #include <sys/namei.h>
79 #include <sys/proc.h>
80 #include <sys/protosw.h>
81 #include <sys/resourcevar.h>
82 #include <sys/rwlock.h>
83 #include <sys/socket.h>
84 #include <sys/socketvar.h>
85 #include <sys/signalvar.h>
86 #include <sys/stat.h>
87 #include <sys/sx.h>
88 #include <sys/sysctl.h>
89 #include <sys/systm.h>
90 #include <sys/taskqueue.h>
91 #include <sys/un.h>
92 #include <sys/unpcb.h>
93 #include <sys/vnode.h>
94
95 #ifdef DDB
96 #include <ddb/ddb.h>
97 #endif
98
99 #include <security/mac/mac_framework.h>
100
101 #include <vm/uma.h>
102
103 static uma_zone_t unp_zone;
104 static unp_gen_t unp_gencnt;
105 static u_int unp_count; /* Count of local sockets. */
106 static ino_t unp_ino; /* Prototype for fake inode numbers. */
107 static int unp_rights; /* File descriptors in flight. */
108 static struct unp_head unp_shead; /* List of local stream sockets. */
109 static struct unp_head unp_dhead; /* List of local datagram sockets. */
110
111 static const struct sockaddr sun_noname = { sizeof(sun_noname), AF_LOCAL };
112
113 /*
114 * Garbage collection of cyclic file descriptor/socket references occurs
115 * asynchronously in a taskqueue context in order to avoid recursion and
116 * reentrance in the UNIX domain socket, file descriptor, and socket layer
117 * code. See unp_gc() for a full description.
118 */
119 static struct task unp_gc_task;
120
121 /*
122 * Both send and receive buffers are allocated PIPSIZ bytes of buffering for
123 * stream sockets, although the total for sender and receiver is actually
124 * only PIPSIZ.
125 *
126 * Datagram sockets really use the sendspace as the maximum datagram size,
127 * and don't really want to reserve the sendspace. Their recvspace should be
128 * large enough for at least one max-size datagram plus address.
129 */
130 #ifndef PIPSIZ
131 #define PIPSIZ 8192
132 #endif
133 static u_long unpst_sendspace = PIPSIZ;
134 static u_long unpst_recvspace = PIPSIZ;
135 static u_long unpdg_sendspace = 2*1024; /* really max datagram size */
136 static u_long unpdg_recvspace = 4*1024;
137
138 SYSCTL_NODE(_net, PF_LOCAL, local, CTLFLAG_RW, 0, "Local domain");
139 SYSCTL_NODE(_net_local, SOCK_STREAM, stream, CTLFLAG_RW, 0, "SOCK_STREAM");
140 SYSCTL_NODE(_net_local, SOCK_DGRAM, dgram, CTLFLAG_RW, 0, "SOCK_DGRAM");
141
142 SYSCTL_ULONG(_net_local_stream, OID_AUTO, sendspace, CTLFLAG_RW,
143 &unpst_sendspace, 0, "");
144 SYSCTL_ULONG(_net_local_stream, OID_AUTO, recvspace, CTLFLAG_RW,
145 &unpst_recvspace, 0, "");
146 SYSCTL_ULONG(_net_local_dgram, OID_AUTO, maxdgram, CTLFLAG_RW,
147 &unpdg_sendspace, 0, "");
148 SYSCTL_ULONG(_net_local_dgram, OID_AUTO, recvspace, CTLFLAG_RW,
149 &unpdg_recvspace, 0, "");
150 SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0, "");
151
152 /*-
153 * Locking and synchronization:
154 *
155 * The global UNIX domain socket rwlock (unp_global_rwlock) protects all
156 * global variables, including the linked lists tracking the set of allocated
157 * UNIX domain sockets. The global rwlock also serves to prevent deadlock
158 * when more than one PCB lock is acquired at a time (i.e., during
159 * connect()). Finally, the global rwlock protects uncounted references from
160 * vnodes to sockets bound to those vnodes: to safely dereference the
161 * v_socket pointer, the global rwlock must be held while a full reference is
162 * acquired.
163 *
164 * UNIX domain sockets each have an unpcb hung off of their so_pcb pointer,
165 * allocated in pru_attach() and freed in pru_detach(). The validity of that
166 * pointer is an invariant, so no lock is required to dereference the so_pcb
167 * pointer if a valid socket reference is held by the caller. In practice,
168 * this is always true during operations performed on a socket. Each unpcb
169 * has a back-pointer to its socket, unp_socket, which will be stable under
170 * the same circumstances.
171 *
172 * This pointer may only be safely dereferenced as long as a valid reference
173 * to the unpcb is held. Typically, this reference will be from the socket,
174 * or from another unpcb when the referring unpcb's lock is held (in order
175 * that the reference not be invalidated during use). For example, to follow
176 * unp->unp_conn->unp_socket, you need unlock the lock on unp, not unp_conn,
177 * as unp_socket remains valid as long as the reference to unp_conn is valid.
178 *
179 * Fields of unpcbss are locked using a per-unpcb lock, unp_mtx. Individual
180 * atomic reads without the lock may be performed "lockless", but more
181 * complex reads and read-modify-writes require the mutex to be held. No
182 * lock order is defined between unpcb locks -- multiple unpcb locks may be
183 * acquired at the same time only when holding the global UNIX domain socket
184 * rwlock exclusively, which prevents deadlocks.
185 *
186 * Blocking with UNIX domain sockets is a tricky issue: unlike most network
187 * protocols, bind() is a non-atomic operation, and connect() requires
188 * potential sleeping in the protocol, due to potentially waiting on local or
189 * distributed file systems. We try to separate "lookup" operations, which
190 * may sleep, and the IPC operations themselves, which typically can occur
191 * with relative atomicity as locks can be held over the entire operation.
192 *
193 * Another tricky issue is simultaneous multi-threaded or multi-process
194 * access to a single UNIX domain socket. These are handled by the flags
195 * UNP_CONNECTING and UNP_BINDING, which prevent concurrent connecting or
196 * binding, both of which involve dropping UNIX domain socket locks in order
197 * to perform namei() and other file system operations.
198 */
199 static struct rwlock unp_global_rwlock;
200
201 #define UNP_GLOBAL_LOCK_INIT() rw_init(&unp_global_rwlock, \
202 "unp_global_rwlock")
203
204 #define UNP_GLOBAL_LOCK_ASSERT() rw_assert(&unp_global_rwlock, \
205 RA_LOCKED)
206 #define UNP_GLOBAL_UNLOCK_ASSERT() rw_assert(&unp_global_rwlock, \
207 RA_UNLOCKED)
208
209 #define UNP_GLOBAL_WLOCK() rw_wlock(&unp_global_rwlock)
210 #define UNP_GLOBAL_WUNLOCK() rw_wunlock(&unp_global_rwlock)
211 #define UNP_GLOBAL_WLOCK_ASSERT() rw_assert(&unp_global_rwlock, \
212 RA_WLOCKED)
213 #define UNP_GLOBAL_WOWNED() rw_wowned(&unp_global_rwlock)
214
215 #define UNP_GLOBAL_RLOCK() rw_rlock(&unp_global_rwlock)
216 #define UNP_GLOBAL_RUNLOCK() rw_runlock(&unp_global_rwlock)
217 #define UNP_GLOBAL_RLOCK_ASSERT() rw_assert(&unp_global_rwlock, \
218 RA_RLOCKED)
219
220 #define UNP_PCB_LOCK_INIT(unp) mtx_init(&(unp)->unp_mtx, \
221 "unp_mtx", "unp_mtx", \
222 MTX_DUPOK|MTX_DEF|MTX_RECURSE)
223 #define UNP_PCB_LOCK_DESTROY(unp) mtx_destroy(&(unp)->unp_mtx)
224 #define UNP_PCB_LOCK(unp) mtx_lock(&(unp)->unp_mtx)
225 #define UNP_PCB_UNLOCK(unp) mtx_unlock(&(unp)->unp_mtx)
226 #define UNP_PCB_LOCK_ASSERT(unp) mtx_assert(&(unp)->unp_mtx, MA_OWNED)
227
228 static int unp_connect(struct socket *, struct sockaddr *,
229 struct thread *);
230 static int unp_connect2(struct socket *so, struct socket *so2, int);
231 static void unp_disconnect(struct unpcb *unp, struct unpcb *unp2);
232 static void unp_shutdown(struct unpcb *);
233 static void unp_drop(struct unpcb *, int);
234 static void unp_gc(__unused void *, int);
235 static void unp_scan(struct mbuf *, void (*)(struct file *));
236 static void unp_mark(struct file *);
237 static void unp_discard(struct file *);
238 static void unp_freerights(struct file **, int);
239 static int unp_internalize(struct mbuf **, struct thread *);
240 static struct mbuf *unp_addsockcred(struct thread *, struct mbuf *);
241
242 /*
243 * Definitions of protocols supported in the LOCAL domain.
244 */
245 static struct domain localdomain;
246 static struct protosw localsw[] = {
247 {
248 .pr_type = SOCK_STREAM,
249 .pr_domain = &localdomain,
250 .pr_flags = PR_CONNREQUIRED|PR_WANTRCVD|PR_RIGHTS,
251 .pr_ctloutput = &uipc_ctloutput,
252 .pr_usrreqs = &uipc_usrreqs
253 },
254 {
255 .pr_type = SOCK_DGRAM,
256 .pr_domain = &localdomain,
257 .pr_flags = PR_ATOMIC|PR_ADDR|PR_RIGHTS,
258 .pr_usrreqs = &uipc_usrreqs
259 },
260 };
261
262 static struct domain localdomain = {
263 .dom_family = AF_LOCAL,
264 .dom_name = "local",
265 .dom_init = unp_init,
266 .dom_externalize = unp_externalize,
267 .dom_dispose = unp_dispose,
268 .dom_protosw = localsw,
269 .dom_protoswNPROTOSW = &localsw[sizeof(localsw)/sizeof(localsw[0])]
270 };
271 DOMAIN_SET(local);
272
273 static void
274 uipc_abort(struct socket *so)
275 {
276 struct unpcb *unp, *unp2;
277
278 unp = sotounpcb(so);
279 KASSERT(unp != NULL, ("uipc_abort: unp == NULL"));
280
281 UNP_GLOBAL_WLOCK();
282 UNP_PCB_LOCK(unp);
283 unp2 = unp->unp_conn;
284 if (unp2 != NULL) {
285 UNP_PCB_LOCK(unp2);
286 unp_drop(unp2, ECONNABORTED);
287 UNP_PCB_UNLOCK(unp2);
288 }
289 UNP_PCB_UNLOCK(unp);
290 UNP_GLOBAL_WUNLOCK();
291 }
292
293 static int
294 uipc_accept(struct socket *so, struct sockaddr **nam)
295 {
296 struct unpcb *unp, *unp2;
297 const struct sockaddr *sa;
298
299 /*
300 * Pass back name of connected socket, if it was bound and we are
301 * still connected (our peer may have closed already!).
302 */
303 unp = sotounpcb(so);
304 KASSERT(unp != NULL, ("uipc_accept: unp == NULL"));
305
306 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
307 UNP_GLOBAL_RLOCK();
308 unp2 = unp->unp_conn;
309 if (unp2 != NULL && unp2->unp_addr != NULL) {
310 UNP_PCB_LOCK(unp2);
311 sa = (struct sockaddr *) unp2->unp_addr;
312 bcopy(sa, *nam, sa->sa_len);
313 UNP_PCB_UNLOCK(unp2);
314 } else {
315 sa = &sun_noname;
316 bcopy(sa, *nam, sa->sa_len);
317 }
318 UNP_GLOBAL_RUNLOCK();
319 return (0);
320 }
321
322 static int
323 uipc_attach(struct socket *so, int proto, struct thread *td)
324 {
325 u_long sendspace, recvspace;
326 struct unpcb *unp;
327 int error, locked;
328
329 KASSERT(so->so_pcb == NULL, ("uipc_attach: so_pcb != NULL"));
330 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
331 switch (so->so_type) {
332 case SOCK_STREAM:
333 sendspace = unpst_sendspace;
334 recvspace = unpst_recvspace;
335 break;
336
337 case SOCK_DGRAM:
338 sendspace = unpdg_sendspace;
339 recvspace = unpdg_recvspace;
340 break;
341
342 default:
343 panic("uipc_attach");
344 }
345 error = soreserve(so, sendspace, recvspace);
346 if (error)
347 return (error);
348 }
349 unp = uma_zalloc(unp_zone, M_NOWAIT | M_ZERO);
350 if (unp == NULL)
351 return (ENOBUFS);
352 LIST_INIT(&unp->unp_refs);
353 UNP_PCB_LOCK_INIT(unp);
354 unp->unp_socket = so;
355 so->so_pcb = unp;
356 unp->unp_refcount = 1;
357
358 /*
359 * uipc_attach() may be called indirectly from within the UNIX domain
360 * socket code via sonewconn() in unp_connect(). Since rwlocks can
361 * not be recursed, we do the closest thing.
362 */
363 locked = 0;
364 if (!UNP_GLOBAL_WOWNED()) {
365 UNP_GLOBAL_WLOCK();
366 locked = 1;
367 }
368 unp->unp_gencnt = ++unp_gencnt;
369 unp_count++;
370 LIST_INSERT_HEAD(so->so_type == SOCK_DGRAM ? &unp_dhead : &unp_shead,
371 unp, unp_link);
372 if (locked)
373 UNP_GLOBAL_WUNLOCK();
374
375 return (0);
376 }
377
378 static int
379 uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
380 {
381 struct sockaddr_un *soun = (struct sockaddr_un *)nam;
382 struct vattr vattr;
383 int error, namelen, vfslocked;
384 struct nameidata nd;
385 struct unpcb *unp;
386 struct vnode *vp;
387 struct mount *mp;
388 char *buf;
389
390 unp = sotounpcb(so);
391 KASSERT(unp != NULL, ("uipc_bind: unp == NULL"));
392
393 namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path);
394 if (namelen <= 0)
395 return (EINVAL);
396
397 /*
398 * We don't allow simultaneous bind() calls on a single UNIX domain
399 * socket, so flag in-progress operations, and return an error if an
400 * operation is already in progress.
401 *
402 * Historically, we have not allowed a socket to be rebound, so this
403 * also returns an error. Not allowing re-binding simplifies the
404 * implementation and avoids a great many possible failure modes.
405 */
406 UNP_PCB_LOCK(unp);
407 if (unp->unp_vnode != NULL) {
408 UNP_PCB_UNLOCK(unp);
409 return (EINVAL);
410 }
411 if (unp->unp_flags & UNP_BINDING) {
412 UNP_PCB_UNLOCK(unp);
413 return (EALREADY);
414 }
415 unp->unp_flags |= UNP_BINDING;
416 UNP_PCB_UNLOCK(unp);
417
418 buf = malloc(namelen + 1, M_TEMP, M_WAITOK);
419 strlcpy(buf, soun->sun_path, namelen + 1);
420
421 restart:
422 vfslocked = 0;
423 NDINIT(&nd, CREATE, MPSAFE | NOFOLLOW | LOCKPARENT | SAVENAME,
424 UIO_SYSSPACE, buf, td);
425 /* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */
426 error = namei(&nd);
427 if (error)
428 goto error;
429 vp = nd.ni_vp;
430 vfslocked = NDHASGIANT(&nd);
431 if (vp != NULL || vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) {
432 NDFREE(&nd, NDF_ONLY_PNBUF);
433 if (nd.ni_dvp == vp)
434 vrele(nd.ni_dvp);
435 else
436 vput(nd.ni_dvp);
437 if (vp != NULL) {
438 vrele(vp);
439 error = EADDRINUSE;
440 goto error;
441 }
442 error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH);
443 if (error)
444 goto error;
445 VFS_UNLOCK_GIANT(vfslocked);
446 goto restart;
447 }
448 VATTR_NULL(&vattr);
449 vattr.va_type = VSOCK;
450 vattr.va_mode = (ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask);
451 #ifdef MAC
452 error = mac_check_vnode_create(td->td_ucred, nd.ni_dvp, &nd.ni_cnd,
453 &vattr);
454 #endif
455 if (error == 0) {
456 VOP_LEASE(nd.ni_dvp, td, td->td_ucred, LEASE_WRITE);
457 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr);
458 }
459 NDFREE(&nd, NDF_ONLY_PNBUF);
460 vput(nd.ni_dvp);
461 if (error) {
462 vn_finished_write(mp);
463 goto error;
464 }
465 vp = nd.ni_vp;
466 ASSERT_VOP_ELOCKED(vp, "uipc_bind");
467 soun = (struct sockaddr_un *)sodupsockaddr(nam, M_WAITOK);
468
469 UNP_GLOBAL_WLOCK();
470 UNP_PCB_LOCK(unp);
471 vp->v_socket = unp->unp_socket;
472 unp->unp_vnode = vp;
473 unp->unp_addr = soun;
474 unp->unp_flags &= ~UNP_BINDING;
475 UNP_PCB_UNLOCK(unp);
476 UNP_GLOBAL_WUNLOCK();
477 VOP_UNLOCK(vp, 0, td);
478 vn_finished_write(mp);
479 VFS_UNLOCK_GIANT(vfslocked);
480 free(buf, M_TEMP);
481 return (0);
482
483 error:
484 VFS_UNLOCK_GIANT(vfslocked);
485 UNP_PCB_LOCK(unp);
486 unp->unp_flags &= ~UNP_BINDING;
487 UNP_PCB_UNLOCK(unp);
488 free(buf, M_TEMP);
489 return (error);
490 }
491
492 static int
493 uipc_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
494 {
495 int error;
496
497 KASSERT(td == curthread, ("uipc_connect: td != curthread"));
498 UNP_GLOBAL_WLOCK();
499 error = unp_connect(so, nam, td);
500 UNP_GLOBAL_WUNLOCK();
501 return (error);
502 }
503
504 static void
505 uipc_close(struct socket *so)
506 {
507 struct unpcb *unp, *unp2;
508
509 unp = sotounpcb(so);
510 KASSERT(unp != NULL, ("uipc_close: unp == NULL"));
511
512 UNP_GLOBAL_WLOCK();
513 UNP_PCB_LOCK(unp);
514 unp2 = unp->unp_conn;
515 if (unp2 != NULL) {
516 UNP_PCB_LOCK(unp2);
517 unp_disconnect(unp, unp2);
518 UNP_PCB_UNLOCK(unp2);
519 }
520 UNP_PCB_UNLOCK(unp);
521 UNP_GLOBAL_WUNLOCK();
522 }
523
524 int
525 uipc_connect2(struct socket *so1, struct socket *so2)
526 {
527 struct unpcb *unp, *unp2;
528 int error;
529
530 UNP_GLOBAL_WLOCK();
531 unp = so1->so_pcb;
532 KASSERT(unp != NULL, ("uipc_connect2: unp == NULL"));
533 UNP_PCB_LOCK(unp);
534 unp2 = so2->so_pcb;
535 KASSERT(unp2 != NULL, ("uipc_connect2: unp2 == NULL"));
536 UNP_PCB_LOCK(unp2);
537 error = unp_connect2(so1, so2, PRU_CONNECT2);
538 UNP_PCB_UNLOCK(unp2);
539 UNP_PCB_UNLOCK(unp);
540 UNP_GLOBAL_WUNLOCK();
541 return (error);
542 }
543
544 /* control is EOPNOTSUPP */
545
546 static void
547 uipc_detach(struct socket *so)
548 {
549 struct unpcb *unp, *unp2;
550 struct sockaddr_un *saved_unp_addr;
551 struct vnode *vp;
552 int freeunp, local_unp_rights;
553
554 unp = sotounpcb(so);
555 KASSERT(unp != NULL, ("uipc_detach: unp == NULL"));
556
557 UNP_GLOBAL_WLOCK();
558 UNP_PCB_LOCK(unp);
559
560 LIST_REMOVE(unp, unp_link);
561 unp->unp_gencnt = ++unp_gencnt;
562 --unp_count;
563
564 /*
565 * XXXRW: Should assert vp->v_socket == so.
566 */
567 if ((vp = unp->unp_vnode) != NULL) {
568 unp->unp_vnode->v_socket = NULL;
569 unp->unp_vnode = NULL;
570 }
571 unp2 = unp->unp_conn;
572 if (unp2 != NULL) {
573 UNP_PCB_LOCK(unp2);
574 unp_disconnect(unp, unp2);
575 UNP_PCB_UNLOCK(unp2);
576 }
577
578 /*
579 * We hold the global lock, so it's OK to acquire multiple pcb locks
580 * at a time.
581 */
582 while (!LIST_EMPTY(&unp->unp_refs)) {
583 struct unpcb *ref = LIST_FIRST(&unp->unp_refs);
584
585 UNP_PCB_LOCK(ref);
586 unp_drop(ref, ECONNRESET);
587 UNP_PCB_UNLOCK(ref);
588 }
589 UNP_GLOBAL_WUNLOCK();
590 unp->unp_socket->so_pcb = NULL;
591 local_unp_rights = unp_rights;
592 saved_unp_addr = unp->unp_addr;
593 unp->unp_addr = NULL;
594 unp->unp_refcount--;
595 freeunp = (unp->unp_refcount == 0);
596 if (saved_unp_addr != NULL)
597 FREE(saved_unp_addr, M_SONAME);
598 if (freeunp) {
599 UNP_PCB_LOCK_DESTROY(unp);
600 uma_zfree(unp_zone, unp);
601 } else
602 UNP_PCB_UNLOCK(unp);
603 if (vp) {
604 int vfslocked;
605
606 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
607 vrele(vp);
608 VFS_UNLOCK_GIANT(vfslocked);
609 }
610 if (local_unp_rights)
611 taskqueue_enqueue(taskqueue_thread, &unp_gc_task);
612 }
613
614 static int
615 uipc_disconnect(struct socket *so)
616 {
617 struct unpcb *unp, *unp2;
618
619 unp = sotounpcb(so);
620 KASSERT(unp != NULL, ("uipc_disconnect: unp == NULL"));
621
622 UNP_GLOBAL_WLOCK();
623 UNP_PCB_LOCK(unp);
624 unp2 = unp->unp_conn;
625 if (unp2 != NULL) {
626 UNP_PCB_LOCK(unp2);
627 unp_disconnect(unp, unp2);
628 UNP_PCB_UNLOCK(unp2);
629 }
630 UNP_PCB_UNLOCK(unp);
631 UNP_GLOBAL_WUNLOCK();
632 return (0);
633 }
634
635 static int
636 uipc_listen(struct socket *so, int backlog, struct thread *td)
637 {
638 struct unpcb *unp;
639 int error;
640
641 unp = sotounpcb(so);
642 KASSERT(unp != NULL, ("uipc_listen: unp == NULL"));
643
644 UNP_PCB_LOCK(unp);
645 if (unp->unp_vnode == NULL) {
646 UNP_PCB_UNLOCK(unp);
647 return (EINVAL);
648 }
649
650 SOCK_LOCK(so);
651 error = solisten_proto_check(so);
652 if (error == 0) {
653 cru2x(td->td_ucred, &unp->unp_peercred);
654 unp->unp_flags |= UNP_HAVEPCCACHED;
655 solisten_proto(so, backlog);
656 }
657 SOCK_UNLOCK(so);
658 UNP_PCB_UNLOCK(unp);
659 return (error);
660 }
661
662 static int
663 uipc_peeraddr(struct socket *so, struct sockaddr **nam)
664 {
665 struct unpcb *unp, *unp2;
666 const struct sockaddr *sa;
667
668 unp = sotounpcb(so);
669 KASSERT(unp != NULL, ("uipc_peeraddr: unp == NULL"));
670
671 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
672 UNP_PCB_LOCK(unp);
673 /*
674 * XXX: It seems that this test always fails even when connection is
675 * established. So, this else clause is added as workaround to
676 * return PF_LOCAL sockaddr.
677 */
678 unp2 = unp->unp_conn;
679 if (unp2 != NULL) {
680 UNP_PCB_LOCK(unp2);
681 if (unp2->unp_addr != NULL)
682 sa = (struct sockaddr *) unp->unp_conn->unp_addr;
683 else
684 sa = &sun_noname;
685 bcopy(sa, *nam, sa->sa_len);
686 UNP_PCB_UNLOCK(unp2);
687 } else {
688 sa = &sun_noname;
689 bcopy(sa, *nam, sa->sa_len);
690 }
691 UNP_PCB_UNLOCK(unp);
692 return (0);
693 }
694
695 static int
696 uipc_rcvd(struct socket *so, int flags)
697 {
698 struct unpcb *unp, *unp2;
699 struct socket *so2;
700 u_int mbcnt, sbcc;
701 u_long newhiwat;
702
703 unp = sotounpcb(so);
704 KASSERT(unp != NULL, ("uipc_rcvd: unp == NULL"));
705
706 if (so->so_type == SOCK_DGRAM)
707 panic("uipc_rcvd DGRAM?");
708
709 if (so->so_type != SOCK_STREAM)
710 panic("uipc_rcvd unknown socktype");
711
712 /*
713 * Adjust backpressure on sender and wakeup any waiting to write.
714 *
715 * The unp lock is acquired to maintain the validity of the unp_conn
716 * pointer; no lock on unp2 is required as unp2->unp_socket will be
717 * static as long as we don't permit unp2 to disconnect from unp,
718 * which is prevented by the lock on unp. We cache values from
719 * so_rcv to avoid holding the so_rcv lock over the entire
720 * transaction on the remote so_snd.
721 */
722 SOCKBUF_LOCK(&so->so_rcv);
723 mbcnt = so->so_rcv.sb_mbcnt;
724 sbcc = so->so_rcv.sb_cc;
725 SOCKBUF_UNLOCK(&so->so_rcv);
726 UNP_PCB_LOCK(unp);
727 unp2 = unp->unp_conn;
728 if (unp2 == NULL) {
729 UNP_PCB_UNLOCK(unp);
730 return (0);
731 }
732 so2 = unp2->unp_socket;
733 SOCKBUF_LOCK(&so2->so_snd);
734 so2->so_snd.sb_mbmax += unp->unp_mbcnt - mbcnt;
735 newhiwat = so2->so_snd.sb_hiwat + unp->unp_cc - sbcc;
736 (void)chgsbsize(so2->so_cred->cr_uidinfo, &so2->so_snd.sb_hiwat,
737 newhiwat, RLIM_INFINITY);
738 sowwakeup_locked(so2);
739 unp->unp_mbcnt = mbcnt;
740 unp->unp_cc = sbcc;
741 UNP_PCB_UNLOCK(unp);
742 return (0);
743 }
744
745 /* pru_rcvoob is EOPNOTSUPP */
746
747 static int
748 uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
749 struct mbuf *control, struct thread *td)
750 {
751 struct unpcb *unp, *unp2;
752 struct socket *so2;
753 u_int mbcnt, sbcc;
754 u_long newhiwat;
755 int error = 0;
756
757 unp = sotounpcb(so);
758 KASSERT(unp != NULL, ("uipc_send: unp == NULL"));
759
760 if (flags & PRUS_OOB) {
761 error = EOPNOTSUPP;
762 goto release;
763 }
764
765 if (control != NULL && (error = unp_internalize(&control, td)))
766 goto release;
767
768 if ((nam != NULL) || (flags & PRUS_EOF))
769 UNP_GLOBAL_WLOCK();
770 else
771 UNP_GLOBAL_RLOCK();
772
773 switch (so->so_type) {
774 case SOCK_DGRAM:
775 {
776 const struct sockaddr *from;
777
778 unp2 = unp->unp_conn;
779 if (nam != NULL) {
780 UNP_GLOBAL_WLOCK_ASSERT();
781 if (unp2 != NULL) {
782 error = EISCONN;
783 break;
784 }
785 error = unp_connect(so, nam, td);
786 if (error)
787 break;
788 unp2 = unp->unp_conn;
789 }
790 /*
791 * Because connect() and send() are non-atomic in a sendto()
792 * with a target address, it's possible that the socket will
793 * have disconnected before the send() can run. In that case
794 * return the slightly counter-intuitive but otherwise
795 * correct error that the socket is not connected.
796 */
797 if (unp2 == NULL) {
798 error = ENOTCONN;
799 break;
800 }
801 /* Lockless read. */
802 if (unp2->unp_flags & UNP_WANTCRED)
803 control = unp_addsockcred(td, control);
804 UNP_PCB_LOCK(unp);
805 if (unp->unp_addr != NULL)
806 from = (struct sockaddr *)unp->unp_addr;
807 else
808 from = &sun_noname;
809 so2 = unp2->unp_socket;
810 SOCKBUF_LOCK(&so2->so_rcv);
811 if (sbappendaddr_locked(&so2->so_rcv, from, m, control)) {
812 sorwakeup_locked(so2);
813 m = NULL;
814 control = NULL;
815 } else {
816 SOCKBUF_UNLOCK(&so2->so_rcv);
817 error = ENOBUFS;
818 }
819 if (nam != NULL) {
820 UNP_GLOBAL_WLOCK_ASSERT();
821 UNP_PCB_LOCK(unp2);
822 unp_disconnect(unp, unp2);
823 UNP_PCB_UNLOCK(unp2);
824 }
825 UNP_PCB_UNLOCK(unp);
826 break;
827 }
828
829 case SOCK_STREAM:
830 /*
831 * Connect if not connected yet.
832 *
833 * Note: A better implementation would complain if not equal
834 * to the peer's address.
835 */
836 if ((so->so_state & SS_ISCONNECTED) == 0) {
837 if (nam != NULL) {
838 UNP_GLOBAL_WLOCK_ASSERT();
839 error = unp_connect(so, nam, td);
840 if (error)
841 break; /* XXX */
842 } else {
843 error = ENOTCONN;
844 break;
845 }
846 }
847
848 /* Lockless read. */
849 if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
850 error = EPIPE;
851 break;
852 }
853 /*
854 * Because connect() and send() are non-atomic in a sendto()
855 * with a target address, it's possible that the socket will
856 * have disconnected before the send() can run. In that case
857 * return the slightly counter-intuitive but otherwise
858 * correct error that the socket is not connected.
859 *
860 * Locking here must be done carefully: the global lock
861 * prevents interconnections between unpcbs from changing, so
862 * we can traverse from unp to unp2 without acquiring unp's
863 * lock. Socket buffer locks follow unpcb locks, so we can
864 * acquire both remote and lock socket buffer locks.
865 */
866 unp2 = unp->unp_conn;
867 if (unp2 == NULL) {
868 error = ENOTCONN;
869 break;
870 }
871 so2 = unp2->unp_socket;
872 UNP_PCB_LOCK(unp2);
873 SOCKBUF_LOCK(&so2->so_rcv);
874 if (unp2->unp_flags & UNP_WANTCRED) {
875 /*
876 * Credentials are passed only once on SOCK_STREAM.
877 */
878 unp2->unp_flags &= ~UNP_WANTCRED;
879 control = unp_addsockcred(td, control);
880 }
881 /*
882 * Send to paired receive port, and then reduce send buffer
883 * hiwater marks to maintain backpressure. Wake up readers.
884 */
885 if (control != NULL) {
886 if (sbappendcontrol_locked(&so2->so_rcv, m, control))
887 control = NULL;
888 } else
889 sbappend_locked(&so2->so_rcv, m);
890 mbcnt = so2->so_rcv.sb_mbcnt - unp2->unp_mbcnt;
891 unp2->unp_mbcnt = so2->so_rcv.sb_mbcnt;
892 sbcc = so2->so_rcv.sb_cc;
893 sorwakeup_locked(so2);
894
895 SOCKBUF_LOCK(&so->so_snd);
896 newhiwat = so->so_snd.sb_hiwat - (sbcc - unp2->unp_cc);
897 (void)chgsbsize(so->so_cred->cr_uidinfo, &so->so_snd.sb_hiwat,
898 newhiwat, RLIM_INFINITY);
899 so->so_snd.sb_mbmax -= mbcnt;
900 SOCKBUF_UNLOCK(&so->so_snd);
901 unp2->unp_cc = sbcc;
902 UNP_PCB_UNLOCK(unp2);
903 m = NULL;
904 break;
905
906 default:
907 panic("uipc_send unknown socktype");
908 }
909
910 /*
911 * SEND_EOF is equivalent to a SEND followed by a SHUTDOWN.
912 */
913 if (flags & PRUS_EOF) {
914 UNP_PCB_LOCK(unp);
915 socantsendmore(so);
916 unp_shutdown(unp);
917 UNP_PCB_UNLOCK(unp);
918 }
919
920 if ((nam != NULL) || (flags & PRUS_EOF))
921 UNP_GLOBAL_WUNLOCK();
922 else
923 UNP_GLOBAL_RUNLOCK();
924
925 if (control != NULL && error != 0)
926 unp_dispose(control);
927
928 release:
929 if (control != NULL)
930 m_freem(control);
931 if (m != NULL)
932 m_freem(m);
933 return (error);
934 }
935
936 static int
937 uipc_sense(struct socket *so, struct stat *sb)
938 {
939 struct unpcb *unp, *unp2;
940 struct socket *so2;
941
942 unp = sotounpcb(so);
943 KASSERT(unp != NULL, ("uipc_sense: unp == NULL"));
944
945 sb->st_blksize = so->so_snd.sb_hiwat;
946 UNP_GLOBAL_RLOCK();
947 UNP_PCB_LOCK(unp);
948 unp2 = unp->unp_conn;
949 if (so->so_type == SOCK_STREAM && unp2 != NULL) {
950 so2 = unp2->unp_socket;
951 sb->st_blksize += so2->so_rcv.sb_cc;
952 }
953 sb->st_dev = NODEV;
954 if (unp->unp_ino == 0)
955 unp->unp_ino = (++unp_ino == 0) ? ++unp_ino : unp_ino;
956 sb->st_ino = unp->unp_ino;
957 UNP_PCB_UNLOCK(unp);
958 UNP_GLOBAL_RUNLOCK();
959 return (0);
960 }
961
962 static int
963 uipc_shutdown(struct socket *so)
964 {
965 struct unpcb *unp;
966
967 unp = sotounpcb(so);
968 KASSERT(unp != NULL, ("uipc_shutdown: unp == NULL"));
969
970 UNP_GLOBAL_WLOCK();
971 UNP_PCB_LOCK(unp);
972 socantsendmore(so);
973 unp_shutdown(unp);
974 UNP_PCB_UNLOCK(unp);
975 UNP_GLOBAL_WUNLOCK();
976 return (0);
977 }
978
979 static int
980 uipc_sockaddr(struct socket *so, struct sockaddr **nam)
981 {
982 struct unpcb *unp;
983 const struct sockaddr *sa;
984
985 unp = sotounpcb(so);
986 KASSERT(unp != NULL, ("uipc_sockaddr: unp == NULL"));
987
988 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
989 UNP_PCB_LOCK(unp);
990 if (unp->unp_addr != NULL)
991 sa = (struct sockaddr *) unp->unp_addr;
992 else
993 sa = &sun_noname;
994 bcopy(sa, *nam, sa->sa_len);
995 UNP_PCB_UNLOCK(unp);
996 return (0);
997 }
998
999 struct pr_usrreqs uipc_usrreqs = {
1000 .pru_abort = uipc_abort,
1001 .pru_accept = uipc_accept,
1002 .pru_attach = uipc_attach,
1003 .pru_bind = uipc_bind,
1004 .pru_connect = uipc_connect,
1005 .pru_connect2 = uipc_connect2,
1006 .pru_detach = uipc_detach,
1007 .pru_disconnect = uipc_disconnect,
1008 .pru_listen = uipc_listen,
1009 .pru_peeraddr = uipc_peeraddr,
1010 .pru_rcvd = uipc_rcvd,
1011 .pru_send = uipc_send,
1012 .pru_sense = uipc_sense,
1013 .pru_shutdown = uipc_shutdown,
1014 .pru_sockaddr = uipc_sockaddr,
1015 .pru_close = uipc_close,
1016 };
1017
1018 int
1019 uipc_ctloutput(struct socket *so, struct sockopt *sopt)
1020 {
1021 struct unpcb *unp;
1022 struct xucred xu;
1023 int error, optval;
1024
1025 if (sopt->sopt_level != 0)
1026 return (EINVAL);
1027
1028 unp = sotounpcb(so);
1029 KASSERT(unp != NULL, ("uipc_ctloutput: unp == NULL"));
1030 error = 0;
1031 switch (sopt->sopt_dir) {
1032 case SOPT_GET:
1033 switch (sopt->sopt_name) {
1034 case LOCAL_PEERCRED:
1035 UNP_PCB_LOCK(unp);
1036 if (unp->unp_flags & UNP_HAVEPC)
1037 xu = unp->unp_peercred;
1038 else {
1039 if (so->so_type == SOCK_STREAM)
1040 error = ENOTCONN;
1041 else
1042 error = EINVAL;
1043 }
1044 UNP_PCB_UNLOCK(unp);
1045 if (error == 0)
1046 error = sooptcopyout(sopt, &xu, sizeof(xu));
1047 break;
1048
1049 case LOCAL_CREDS:
1050 /* Unocked read. */
1051 optval = unp->unp_flags & UNP_WANTCRED ? 1 : 0;
1052 error = sooptcopyout(sopt, &optval, sizeof(optval));
1053 break;
1054
1055 case LOCAL_CONNWAIT:
1056 /* Unocked read. */
1057 optval = unp->unp_flags & UNP_CONNWAIT ? 1 : 0;
1058 error = sooptcopyout(sopt, &optval, sizeof(optval));
1059 break;
1060
1061 default:
1062 error = EOPNOTSUPP;
1063 break;
1064 }
1065 break;
1066
1067 case SOPT_SET:
1068 switch (sopt->sopt_name) {
1069 case LOCAL_CREDS:
1070 case LOCAL_CONNWAIT:
1071 error = sooptcopyin(sopt, &optval, sizeof(optval),
1072 sizeof(optval));
1073 if (error)
1074 break;
1075
1076 #define OPTSET(bit) do { \
1077 UNP_PCB_LOCK(unp); \
1078 if (optval) \
1079 unp->unp_flags |= bit; \
1080 else \
1081 unp->unp_flags &= ~bit; \
1082 UNP_PCB_UNLOCK(unp); \
1083 } while (0)
1084
1085 switch (sopt->sopt_name) {
1086 case LOCAL_CREDS:
1087 OPTSET(UNP_WANTCRED);
1088 break;
1089
1090 case LOCAL_CONNWAIT:
1091 OPTSET(UNP_CONNWAIT);
1092 break;
1093
1094 default:
1095 break;
1096 }
1097 break;
1098 #undef OPTSET
1099 default:
1100 error = ENOPROTOOPT;
1101 break;
1102 }
1103 break;
1104
1105 default:
1106 error = EOPNOTSUPP;
1107 break;
1108 }
1109 return (error);
1110 }
1111
1112 static int
1113 unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
1114 {
1115 struct sockaddr_un *soun = (struct sockaddr_un *)nam;
1116 struct vnode *vp;
1117 struct socket *so2, *so3;
1118 struct unpcb *unp, *unp2, *unp3;
1119 int error, len, vfslocked;
1120 struct nameidata nd;
1121 char buf[SOCK_MAXADDRLEN];
1122 struct sockaddr *sa;
1123
1124 UNP_GLOBAL_WLOCK_ASSERT();
1125
1126 unp = sotounpcb(so);
1127 KASSERT(unp != NULL, ("unp_connect: unp == NULL"));
1128
1129 len = nam->sa_len - offsetof(struct sockaddr_un, sun_path);
1130 if (len <= 0)
1131 return (EINVAL);
1132 strlcpy(buf, soun->sun_path, len + 1);
1133
1134 UNP_PCB_LOCK(unp);
1135 if (unp->unp_flags & UNP_CONNECTING) {
1136 UNP_PCB_UNLOCK(unp);
1137 return (EALREADY);
1138 }
1139 UNP_GLOBAL_WUNLOCK();
1140 unp->unp_flags |= UNP_CONNECTING;
1141 UNP_PCB_UNLOCK(unp);
1142
1143 sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
1144 NDINIT(&nd, LOOKUP, MPSAFE | FOLLOW | LOCKLEAF, UIO_SYSSPACE, buf,
1145 td);
1146 error = namei(&nd);
1147 if (error)
1148 vp = NULL;
1149 else
1150 vp = nd.ni_vp;
1151 ASSERT_VOP_LOCKED(vp, "unp_connect");
1152 vfslocked = NDHASGIANT(&nd);
1153 NDFREE(&nd, NDF_ONLY_PNBUF);
1154 if (error)
1155 goto bad;
1156
1157 if (vp->v_type != VSOCK) {
1158 error = ENOTSOCK;
1159 goto bad;
1160 }
1161 #ifdef MAC
1162 error = mac_check_vnode_open(td->td_ucred, vp, VWRITE | VREAD);
1163 if (error)
1164 goto bad;
1165 #endif
1166 error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td);
1167 if (error)
1168 goto bad;
1169 VFS_UNLOCK_GIANT(vfslocked);
1170
1171 unp = sotounpcb(so);
1172 KASSERT(unp != NULL, ("unp_connect: unp == NULL"));
1173
1174 /*
1175 * Lock global lock for two reasons: make sure v_socket is stable,
1176 * and to protect simultaneous locking of multiple pcbs.
1177 */
1178 UNP_GLOBAL_WLOCK();
1179 so2 = vp->v_socket;
1180 if (so2 == NULL) {
1181 error = ECONNREFUSED;
1182 goto bad2;
1183 }
1184 if (so->so_type != so2->so_type) {
1185 error = EPROTOTYPE;
1186 goto bad2;
1187 }
1188 if (so->so_proto->pr_flags & PR_CONNREQUIRED) {
1189 if (so2->so_options & SO_ACCEPTCONN) {
1190 /*
1191 * We can't drop the global lock here or 'so2' may
1192 * become invalid. As a result, we need to handle
1193 * possibly lock recursion in uipc_attach.
1194 */
1195 so3 = sonewconn(so2, 0);
1196 } else
1197 so3 = NULL;
1198 if (so3 == NULL) {
1199 error = ECONNREFUSED;
1200 goto bad2;
1201 }
1202 unp = sotounpcb(so);
1203 unp2 = sotounpcb(so2);
1204 unp3 = sotounpcb(so3);
1205 UNP_PCB_LOCK(unp);
1206 UNP_PCB_LOCK(unp2);
1207 UNP_PCB_LOCK(unp3);
1208 if (unp2->unp_addr != NULL) {
1209 bcopy(unp2->unp_addr, sa, unp2->unp_addr->sun_len);
1210 unp3->unp_addr = (struct sockaddr_un *) sa;
1211 sa = NULL;
1212 }
1213 /*
1214 * unp_peercred management:
1215 *
1216 * The connecter's (client's) credentials are copied from its
1217 * process structure at the time of connect() (which is now).
1218 */
1219 cru2x(td->td_ucred, &unp3->unp_peercred);
1220 unp3->unp_flags |= UNP_HAVEPC;
1221 /*
1222 * The receiver's (server's) credentials are copied from the
1223 * unp_peercred member of socket on which the former called
1224 * listen(); uipc_listen() cached that process's credentials
1225 * at that time so we can use them now.
1226 */
1227 KASSERT(unp2->unp_flags & UNP_HAVEPCCACHED,
1228 ("unp_connect: listener without cached peercred"));
1229 memcpy(&unp->unp_peercred, &unp2->unp_peercred,
1230 sizeof(unp->unp_peercred));
1231 unp->unp_flags |= UNP_HAVEPC;
1232 if (unp2->unp_flags & UNP_WANTCRED)
1233 unp3->unp_flags |= UNP_WANTCRED;
1234 UNP_PCB_UNLOCK(unp3);
1235 UNP_PCB_UNLOCK(unp2);
1236 UNP_PCB_UNLOCK(unp);
1237 #ifdef MAC
1238 SOCK_LOCK(so);
1239 mac_set_socket_peer_from_socket(so, so3);
1240 mac_set_socket_peer_from_socket(so3, so);
1241 SOCK_UNLOCK(so);
1242 #endif
1243
1244 so2 = so3;
1245 }
1246 unp = sotounpcb(so);
1247 KASSERT(unp != NULL, ("unp_connect: unp == NULL"));
1248 unp2 = sotounpcb(so2);
1249 KASSERT(unp2 != NULL, ("unp_connect: unp2 == NULL"));
1250 UNP_PCB_LOCK(unp);
1251 UNP_PCB_LOCK(unp2);
1252 error = unp_connect2(so, so2, PRU_CONNECT);
1253 UNP_PCB_UNLOCK(unp2);
1254 UNP_PCB_UNLOCK(unp);
1255 bad2:
1256 UNP_GLOBAL_WUNLOCK();
1257 if (vfslocked)
1258 /*
1259 * Giant has been previously acquired. This means filesystem
1260 * isn't MPSAFE. Do it once again.
1261 */
1262 mtx_lock(&Giant);
1263 bad:
1264 if (vp != NULL)
1265 vput(vp);
1266 VFS_UNLOCK_GIANT(vfslocked);
1267 free(sa, M_SONAME);
1268 UNP_GLOBAL_WLOCK();
1269 UNP_PCB_LOCK(unp);
1270 unp->unp_flags &= ~UNP_CONNECTING;
1271 UNP_PCB_UNLOCK(unp);
1272 return (error);
1273 }
1274
1275 static int
1276 unp_connect2(struct socket *so, struct socket *so2, int req)
1277 {
1278 struct unpcb *unp;
1279 struct unpcb *unp2;
1280
1281 unp = sotounpcb(so);
1282 KASSERT(unp != NULL, ("unp_connect2: unp == NULL"));
1283 unp2 = sotounpcb(so2);
1284 KASSERT(unp2 != NULL, ("unp_connect2: unp2 == NULL"));
1285
1286 UNP_GLOBAL_WLOCK_ASSERT();
1287 UNP_PCB_LOCK_ASSERT(unp);
1288 UNP_PCB_LOCK_ASSERT(unp2);
1289
1290 if (so2->so_type != so->so_type)
1291 return (EPROTOTYPE);
1292 unp->unp_conn = unp2;
1293
1294 switch (so->so_type) {
1295 case SOCK_DGRAM:
1296 LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink);
1297 soisconnected(so);
1298 break;
1299
1300 case SOCK_STREAM:
1301 unp2->unp_conn = unp;
1302 if (req == PRU_CONNECT &&
1303 ((unp->unp_flags | unp2->unp_flags) & UNP_CONNWAIT))
1304 soisconnecting(so);
1305 else
1306 soisconnected(so);
1307 soisconnected(so2);
1308 break;
1309
1310 default:
1311 panic("unp_connect2");
1312 }
1313 return (0);
1314 }
1315
1316 static void
1317 unp_disconnect(struct unpcb *unp, struct unpcb *unp2)
1318 {
1319 struct socket *so;
1320
1321 KASSERT(unp2 != NULL, ("unp_disconnect: unp2 == NULL"));
1322
1323 UNP_GLOBAL_WLOCK_ASSERT();
1324 UNP_PCB_LOCK_ASSERT(unp);
1325 UNP_PCB_LOCK_ASSERT(unp2);
1326
1327 unp->unp_conn = NULL;
1328 switch (unp->unp_socket->so_type) {
1329 case SOCK_DGRAM:
1330 LIST_REMOVE(unp, unp_reflink);
1331 so = unp->unp_socket;
1332 SOCK_LOCK(so);
1333 so->so_state &= ~SS_ISCONNECTED;
1334 SOCK_UNLOCK(so);
1335 break;
1336
1337 case SOCK_STREAM:
1338 soisdisconnected(unp->unp_socket);
1339 unp2->unp_conn = NULL;
1340 soisdisconnected(unp2->unp_socket);
1341 break;
1342 }
1343 }
1344
1345 /*
1346 * unp_pcblist() walks the global list of struct unpcb's to generate a
1347 * pointer list, bumping the refcount on each unpcb. It then copies them out
1348 * sequentially, validating the generation number on each to see if it has
1349 * been detached. All of this is necessary because copyout() may sleep on
1350 * disk I/O.
1351 */
1352 static int
1353 unp_pcblist(SYSCTL_HANDLER_ARGS)
1354 {
1355 int error, i, n;
1356 int freeunp;
1357 struct unpcb *unp, **unp_list;
1358 unp_gen_t gencnt;
1359 struct xunpgen *xug;
1360 struct unp_head *head;
1361 struct xunpcb *xu;
1362
1363 head = ((intptr_t)arg1 == SOCK_DGRAM ? &unp_dhead : &unp_shead);
1364
1365 /*
1366 * The process of preparing the PCB list is too time-consuming and
1367 * resource-intensive to repeat twice on every request.
1368 */
1369 if (req->oldptr == NULL) {
1370 n = unp_count;
1371 req->oldidx = 2 * (sizeof *xug)
1372 + (n + n/8) * sizeof(struct xunpcb);
1373 return (0);
1374 }
1375
1376 if (req->newptr != NULL)
1377 return (EPERM);
1378
1379 /*
1380 * OK, now we're committed to doing something.
1381 */
1382 xug = malloc(sizeof(*xug), M_TEMP, M_WAITOK);
1383 UNP_GLOBAL_RLOCK();
1384 gencnt = unp_gencnt;
1385 n = unp_count;
1386 UNP_GLOBAL_RUNLOCK();
1387
1388 xug->xug_len = sizeof *xug;
1389 xug->xug_count = n;
1390 xug->xug_gen = gencnt;
1391 xug->xug_sogen = so_gencnt;
1392 error = SYSCTL_OUT(req, xug, sizeof *xug);
1393 if (error) {
1394 free(xug, M_TEMP);
1395 return (error);
1396 }
1397
1398 unp_list = malloc(n * sizeof *unp_list, M_TEMP, M_WAITOK);
1399
1400 UNP_GLOBAL_RLOCK();
1401 for (unp = LIST_FIRST(head), i = 0; unp && i < n;
1402 unp = LIST_NEXT(unp, unp_link)) {
1403 UNP_PCB_LOCK(unp);
1404 if (unp->unp_gencnt <= gencnt) {
1405 if (cr_cansee(req->td->td_ucred,
1406 unp->unp_socket->so_cred)) {
1407 UNP_PCB_UNLOCK(unp);
1408 continue;
1409 }
1410 unp_list[i++] = unp;
1411 unp->unp_refcount++;
1412 }
1413 UNP_PCB_UNLOCK(unp);
1414 }
1415 UNP_GLOBAL_RUNLOCK();
1416 n = i; /* In case we lost some during malloc. */
1417
1418 error = 0;
1419 xu = malloc(sizeof(*xu), M_TEMP, M_WAITOK | M_ZERO);
1420 for (i = 0; i < n; i++) {
1421 unp = unp_list[i];
1422 UNP_PCB_LOCK(unp);
1423 unp->unp_refcount--;
1424 if (unp->unp_refcount != 0 && unp->unp_gencnt <= gencnt) {
1425 xu->xu_len = sizeof *xu;
1426 xu->xu_unpp = unp;
1427 /*
1428 * XXX - need more locking here to protect against
1429 * connect/disconnect races for SMP.
1430 */
1431 if (unp->unp_addr != NULL)
1432 bcopy(unp->unp_addr, &xu->xu_addr,
1433 unp->unp_addr->sun_len);
1434 if (unp->unp_conn != NULL &&
1435 unp->unp_conn->unp_addr != NULL)
1436 bcopy(unp->unp_conn->unp_addr,
1437 &xu->xu_caddr,
1438 unp->unp_conn->unp_addr->sun_len);
1439 bcopy(unp, &xu->xu_unp, sizeof *unp);
1440 sotoxsocket(unp->unp_socket, &xu->xu_socket);
1441 UNP_PCB_UNLOCK(unp);
1442 error = SYSCTL_OUT(req, xu, sizeof *xu);
1443 } else {
1444 freeunp = (unp->unp_refcount == 0);
1445 UNP_PCB_UNLOCK(unp);
1446 if (freeunp) {
1447 UNP_PCB_LOCK_DESTROY(unp);
1448 uma_zfree(unp_zone, unp);
1449 }
1450 }
1451 }
1452 free(xu, M_TEMP);
1453 if (!error) {
1454 /*
1455 * Give the user an updated idea of our state. If the
1456 * generation differs from what we told her before, she knows
1457 * that something happened while we were processing this
1458 * request, and it might be necessary to retry.
1459 */
1460 xug->xug_gen = unp_gencnt;
1461 xug->xug_sogen = so_gencnt;
1462 xug->xug_count = unp_count;
1463 error = SYSCTL_OUT(req, xug, sizeof *xug);
1464 }
1465 free(unp_list, M_TEMP);
1466 free(xug, M_TEMP);
1467 return (error);
1468 }
1469
1470 SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLFLAG_RD,
1471 (caddr_t)(long)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb",
1472 "List of active local datagram sockets");
1473 SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLFLAG_RD,
1474 (caddr_t)(long)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb",
1475 "List of active local stream sockets");
1476
1477 static void
1478 unp_shutdown(struct unpcb *unp)
1479 {
1480 struct unpcb *unp2;
1481 struct socket *so;
1482
1483 UNP_GLOBAL_WLOCK_ASSERT();
1484 UNP_PCB_LOCK_ASSERT(unp);
1485
1486 unp2 = unp->unp_conn;
1487 if (unp->unp_socket->so_type == SOCK_STREAM && unp2 != NULL) {
1488 so = unp2->unp_socket;
1489 if (so != NULL)
1490 socantrcvmore(so);
1491 }
1492 }
1493
1494 static void
1495 unp_drop(struct unpcb *unp, int errno)
1496 {
1497 struct socket *so = unp->unp_socket;
1498 struct unpcb *unp2;
1499
1500 UNP_GLOBAL_WLOCK_ASSERT();
1501 UNP_PCB_LOCK_ASSERT(unp);
1502
1503 so->so_error = errno;
1504 unp2 = unp->unp_conn;
1505 if (unp2 == NULL)
1506 return;
1507
1508 UNP_PCB_LOCK(unp2);
1509 unp_disconnect(unp, unp2);
1510 UNP_PCB_UNLOCK(unp2);
1511 }
1512
1513 static void
1514 unp_freerights(struct file **rp, int fdcount)
1515 {
1516 int i;
1517 struct file *fp;
1518
1519 for (i = 0; i < fdcount; i++) {
1520 /*
1521 * Zero the pointer before calling unp_discard since it may
1522 * end up in unp_gc()..
1523 *
1524 * XXXRW: This is less true than it used to be.
1525 */
1526 fp = *rp;
1527 *rp++ = NULL;
1528 unp_discard(fp);
1529 }
1530 }
1531
1532 int
1533 unp_externalize(struct mbuf *control, struct mbuf **controlp)
1534 {
1535 struct thread *td = curthread; /* XXX */
1536 struct cmsghdr *cm = mtod(control, struct cmsghdr *);
1537 int i;
1538 int *fdp;
1539 struct file **rp;
1540 struct file *fp;
1541 void *data;
1542 socklen_t clen = control->m_len, datalen;
1543 int error, newfds;
1544 int f;
1545 u_int newlen;
1546
1547 UNP_GLOBAL_UNLOCK_ASSERT();
1548
1549 error = 0;
1550 if (controlp != NULL) /* controlp == NULL => free control messages */
1551 *controlp = NULL;
1552
1553 while (cm != NULL) {
1554 if (sizeof(*cm) > clen || cm->cmsg_len > clen) {
1555 error = EINVAL;
1556 break;
1557 }
1558
1559 data = CMSG_DATA(cm);
1560 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data;
1561
1562 if (cm->cmsg_level == SOL_SOCKET
1563 && cm->cmsg_type == SCM_RIGHTS) {
1564 newfds = datalen / sizeof(struct file *);
1565 rp = data;
1566
1567 /* If we're not outputting the descriptors free them. */
1568 if (error || controlp == NULL) {
1569 unp_freerights(rp, newfds);
1570 goto next;
1571 }
1572 FILEDESC_XLOCK(td->td_proc->p_fd);
1573 /* if the new FD's will not fit free them. */
1574 if (!fdavail(td, newfds)) {
1575 FILEDESC_XUNLOCK(td->td_proc->p_fd);
1576 error = EMSGSIZE;
1577 unp_freerights(rp, newfds);
1578 goto next;
1579 }
1580 /*
1581 * Now change each pointer to an fd in the global
1582 * table to an integer that is the index to the local
1583 * fd table entry that we set up to point to the
1584 * global one we are transferring.
1585 */
1586 newlen = newfds * sizeof(int);
1587 *controlp = sbcreatecontrol(NULL, newlen,
1588 SCM_RIGHTS, SOL_SOCKET);
1589 if (*controlp == NULL) {
1590 FILEDESC_XUNLOCK(td->td_proc->p_fd);
1591 error = E2BIG;
1592 unp_freerights(rp, newfds);
1593 goto next;
1594 }
1595
1596 fdp = (int *)
1597 CMSG_DATA(mtod(*controlp, struct cmsghdr *));
1598 for (i = 0; i < newfds; i++) {
1599 if (fdalloc(td, 0, &f))
1600 panic("unp_externalize fdalloc failed");
1601 fp = *rp++;
1602 td->td_proc->p_fd->fd_ofiles[f] = fp;
1603 FILE_LOCK(fp);
1604 fp->f_msgcount--;
1605 FILE_UNLOCK(fp);
1606 unp_rights--;
1607 *fdp++ = f;
1608 }
1609 FILEDESC_XUNLOCK(td->td_proc->p_fd);
1610 } else {
1611 /* We can just copy anything else across. */
1612 if (error || controlp == NULL)
1613 goto next;
1614 *controlp = sbcreatecontrol(NULL, datalen,
1615 cm->cmsg_type, cm->cmsg_level);
1616 if (*controlp == NULL) {
1617 error = ENOBUFS;
1618 goto next;
1619 }
1620 bcopy(data,
1621 CMSG_DATA(mtod(*controlp, struct cmsghdr *)),
1622 datalen);
1623 }
1624
1625 controlp = &(*controlp)->m_next;
1626
1627 next:
1628 if (CMSG_SPACE(datalen) < clen) {
1629 clen -= CMSG_SPACE(datalen);
1630 cm = (struct cmsghdr *)
1631 ((caddr_t)cm + CMSG_SPACE(datalen));
1632 } else {
1633 clen = 0;
1634 cm = NULL;
1635 }
1636 }
1637
1638 m_freem(control);
1639
1640 return (error);
1641 }
1642
1643 static void
1644 unp_zone_change(void *tag)
1645 {
1646
1647 uma_zone_set_max(unp_zone, maxsockets);
1648 }
1649
1650 void
1651 unp_init(void)
1652 {
1653
1654 unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, NULL,
1655 NULL, NULL, UMA_ALIGN_PTR, 0);
1656 if (unp_zone == NULL)
1657 panic("unp_init");
1658 uma_zone_set_max(unp_zone, maxsockets);
1659 EVENTHANDLER_REGISTER(maxsockets_change, unp_zone_change,
1660 NULL, EVENTHANDLER_PRI_ANY);
1661 LIST_INIT(&unp_dhead);
1662 LIST_INIT(&unp_shead);
1663 TASK_INIT(&unp_gc_task, 0, unp_gc, NULL);
1664 UNP_GLOBAL_LOCK_INIT();
1665 }
1666
1667 static int
1668 unp_internalize(struct mbuf **controlp, struct thread *td)
1669 {
1670 struct mbuf *control = *controlp;
1671 struct proc *p = td->td_proc;
1672 struct filedesc *fdescp = p->p_fd;
1673 struct cmsghdr *cm = mtod(control, struct cmsghdr *);
1674 struct cmsgcred *cmcred;
1675 struct file **rp;
1676 struct file *fp;
1677 struct timeval *tv;
1678 int i, fd, *fdp;
1679 void *data;
1680 socklen_t clen = control->m_len, datalen;
1681 int error, oldfds;
1682 u_int newlen;
1683
1684 UNP_GLOBAL_UNLOCK_ASSERT();
1685
1686 error = 0;
1687 *controlp = NULL;
1688
1689 while (cm != NULL) {
1690 if (sizeof(*cm) > clen || cm->cmsg_level != SOL_SOCKET
1691 || cm->cmsg_len > clen) {
1692 error = EINVAL;
1693 goto out;
1694 }
1695
1696 data = CMSG_DATA(cm);
1697 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data;
1698
1699 switch (cm->cmsg_type) {
1700 /*
1701 * Fill in credential information.
1702 */
1703 case SCM_CREDS:
1704 *controlp = sbcreatecontrol(NULL, sizeof(*cmcred),
1705 SCM_CREDS, SOL_SOCKET);
1706 if (*controlp == NULL) {
1707 error = ENOBUFS;
1708 goto out;
1709 }
1710
1711 cmcred = (struct cmsgcred *)
1712 CMSG_DATA(mtod(*controlp, struct cmsghdr *));
1713 cmcred->cmcred_pid = p->p_pid;
1714 cmcred->cmcred_uid = td->td_ucred->cr_ruid;
1715 cmcred->cmcred_gid = td->td_ucred->cr_rgid;
1716 cmcred->cmcred_euid = td->td_ucred->cr_uid;
1717 cmcred->cmcred_ngroups = MIN(td->td_ucred->cr_ngroups,
1718 CMGROUP_MAX);
1719 for (i = 0; i < cmcred->cmcred_ngroups; i++)
1720 cmcred->cmcred_groups[i] =
1721 td->td_ucred->cr_groups[i];
1722 break;
1723
1724 case SCM_RIGHTS:
1725 oldfds = datalen / sizeof (int);
1726 /*
1727 * Check that all the FDs passed in refer to legal
1728 * files. If not, reject the entire operation.
1729 */
1730 fdp = data;
1731 FILEDESC_SLOCK(fdescp);
1732 for (i = 0; i < oldfds; i++) {
1733 fd = *fdp++;
1734 if ((unsigned)fd >= fdescp->fd_nfiles ||
1735 fdescp->fd_ofiles[fd] == NULL) {
1736 FILEDESC_SUNLOCK(fdescp);
1737 error = EBADF;
1738 goto out;
1739 }
1740 fp = fdescp->fd_ofiles[fd];
1741 if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) {
1742 FILEDESC_SUNLOCK(fdescp);
1743 error = EOPNOTSUPP;
1744 goto out;
1745 }
1746
1747 }
1748
1749 /*
1750 * Now replace the integer FDs with pointers to
1751 * the associated global file table entry..
1752 */
1753 newlen = oldfds * sizeof(struct file *);
1754 *controlp = sbcreatecontrol(NULL, newlen,
1755 SCM_RIGHTS, SOL_SOCKET);
1756 if (*controlp == NULL) {
1757 FILEDESC_SUNLOCK(fdescp);
1758 error = E2BIG;
1759 goto out;
1760 }
1761
1762 fdp = data;
1763 rp = (struct file **)
1764 CMSG_DATA(mtod(*controlp, struct cmsghdr *));
1765 for (i = 0; i < oldfds; i++) {
1766 fp = fdescp->fd_ofiles[*fdp++];
1767 *rp++ = fp;
1768 FILE_LOCK(fp);
1769 fp->f_count++;
1770 fp->f_msgcount++;
1771 FILE_UNLOCK(fp);
1772 unp_rights++;
1773 }
1774 FILEDESC_SUNLOCK(fdescp);
1775 break;
1776
1777 case SCM_TIMESTAMP:
1778 *controlp = sbcreatecontrol(NULL, sizeof(*tv),
1779 SCM_TIMESTAMP, SOL_SOCKET);
1780 if (*controlp == NULL) {
1781 error = ENOBUFS;
1782 goto out;
1783 }
1784 tv = (struct timeval *)
1785 CMSG_DATA(mtod(*controlp, struct cmsghdr *));
1786 microtime(tv);
1787 break;
1788
1789 default:
1790 error = EINVAL;
1791 goto out;
1792 }
1793
1794 controlp = &(*controlp)->m_next;
1795
1796 if (CMSG_SPACE(datalen) < clen) {
1797 clen -= CMSG_SPACE(datalen);
1798 cm = (struct cmsghdr *)
1799 ((caddr_t)cm + CMSG_SPACE(datalen));
1800 } else {
1801 clen = 0;
1802 cm = NULL;
1803 }
1804 }
1805
1806 out:
1807 m_freem(control);
1808
1809 return (error);
1810 }
1811
1812 static struct mbuf *
1813 unp_addsockcred(struct thread *td, struct mbuf *control)
1814 {
1815 struct mbuf *m, *n, *n_prev;
1816 struct sockcred *sc;
1817 const struct cmsghdr *cm;
1818 int ngroups;
1819 int i;
1820
1821 ngroups = MIN(td->td_ucred->cr_ngroups, CMGROUP_MAX);
1822
1823 m = sbcreatecontrol(NULL, SOCKCREDSIZE(ngroups), SCM_CREDS, SOL_SOCKET);
1824 if (m == NULL)
1825 return (control);
1826
1827 sc = (struct sockcred *) CMSG_DATA(mtod(m, struct cmsghdr *));
1828 sc->sc_uid = td->td_ucred->cr_ruid;
1829 sc->sc_euid = td->td_ucred->cr_uid;
1830 sc->sc_gid = td->td_ucred->cr_rgid;
1831 sc->sc_egid = td->td_ucred->cr_gid;
1832 sc->sc_ngroups = ngroups;
1833 for (i = 0; i < sc->sc_ngroups; i++)
1834 sc->sc_groups[i] = td->td_ucred->cr_groups[i];
1835
1836 /*
1837 * Unlink SCM_CREDS control messages (struct cmsgcred), since just
1838 * created SCM_CREDS control message (struct sockcred) has another
1839 * format.
1840 */
1841 if (control != NULL)
1842 for (n = control, n_prev = NULL; n != NULL;) {
1843 cm = mtod(n, struct cmsghdr *);
1844 if (cm->cmsg_level == SOL_SOCKET &&
1845 cm->cmsg_type == SCM_CREDS) {
1846 if (n_prev == NULL)
1847 control = n->m_next;
1848 else
1849 n_prev->m_next = n->m_next;
1850 n = m_free(n);
1851 } else {
1852 n_prev = n;
1853 n = n->m_next;
1854 }
1855 }
1856
1857 /* Prepend it to the head. */
1858 m->m_next = control;
1859
1860 return (m);
1861 }
1862
1863 /*
1864 * unp_defer indicates whether additional work has been defered for a future
1865 * pass through unp_gc(). It is thread local and does not require explicit
1866 * synchronization.
1867 */
1868 static int unp_defer;
1869
1870 static int unp_taskcount;
1871 SYSCTL_INT(_net_local, OID_AUTO, taskcount, CTLFLAG_RD, &unp_taskcount, 0, "");
1872
1873 static int unp_recycled;
1874 SYSCTL_INT(_net_local, OID_AUTO, recycled, CTLFLAG_RD, &unp_recycled, 0, "");
1875
1876 static void
1877 unp_gc(__unused void *arg, int pending)
1878 {
1879 struct file *fp, *nextfp;
1880 struct socket *so;
1881 struct file **extra_ref, **fpp;
1882 int nunref, i;
1883 int nfiles_snap;
1884 int nfiles_slack = 20;
1885
1886 unp_taskcount++;
1887 unp_defer = 0;
1888 /*
1889 * Before going through all this, set all FDs to be NOT deferred and
1890 * NOT externally accessible.
1891 */
1892 sx_slock(&filelist_lock);
1893 LIST_FOREACH(fp, &filehead, f_list)
1894 fp->f_gcflag &= ~(FMARK|FDEFER);
1895 do {
1896 KASSERT(unp_defer >= 0, ("unp_gc: unp_defer %d", unp_defer));
1897 LIST_FOREACH(fp, &filehead, f_list) {
1898 FILE_LOCK(fp);
1899 /*
1900 * If the file is not open, skip it -- could be a
1901 * file in the process of being opened, or in the
1902 * process of being closed. If the file is
1903 * "closing", it may have been marked for deferred
1904 * consideration. Clear the flag now if so.
1905 */
1906 if (fp->f_count == 0) {
1907 if (fp->f_gcflag & FDEFER)
1908 unp_defer--;
1909 fp->f_gcflag &= ~(FMARK|FDEFER);
1910 FILE_UNLOCK(fp);
1911 continue;
1912 }
1913 /*
1914 * If we already marked it as 'defer' in a
1915 * previous pass, then try to process it this
1916 * time and un-mark it.
1917 */
1918 if (fp->f_gcflag & FDEFER) {
1919 fp->f_gcflag &= ~FDEFER;
1920 unp_defer--;
1921 } else {
1922 /*
1923 * If it's not deferred, then check if it's
1924 * already marked.. if so skip it
1925 */
1926 if (fp->f_gcflag & FMARK) {
1927 FILE_UNLOCK(fp);
1928 continue;
1929 }
1930 /*
1931 * If all references are from messages in
1932 * transit, then skip it. it's not externally
1933 * accessible.
1934 */
1935 if (fp->f_count == fp->f_msgcount) {
1936 FILE_UNLOCK(fp);
1937 continue;
1938 }
1939 /*
1940 * If it got this far then it must be
1941 * externally accessible.
1942 */
1943 fp->f_gcflag |= FMARK;
1944 }
1945 /*
1946 * Either it was deferred, or it is externally
1947 * accessible and not already marked so. Now check
1948 * if it is possibly one of OUR sockets.
1949 */
1950 if (fp->f_type != DTYPE_SOCKET ||
1951 (so = fp->f_data) == NULL) {
1952 FILE_UNLOCK(fp);
1953 continue;
1954 }
1955 if (so->so_proto->pr_domain != &localdomain ||
1956 (so->so_proto->pr_flags & PR_RIGHTS) == 0) {
1957 FILE_UNLOCK(fp);
1958 continue;
1959 }
1960
1961 /*
1962 * Tell any other threads that do a subsequent
1963 * fdrop() that we are scanning the message
1964 * buffers.
1965 */
1966 fp->f_gcflag |= FWAIT;
1967 FILE_UNLOCK(fp);
1968
1969 /*
1970 * So, Ok, it's one of our sockets and it IS
1971 * externally accessible (or was deferred). Now we
1972 * look to see if we hold any file descriptors in its
1973 * message buffers. Follow those links and mark them
1974 * as accessible too.
1975 */
1976 SOCKBUF_LOCK(&so->so_rcv);
1977 unp_scan(so->so_rcv.sb_mb, unp_mark);
1978 SOCKBUF_UNLOCK(&so->so_rcv);
1979
1980 /*
1981 * Wake up any threads waiting in fdrop().
1982 */
1983 FILE_LOCK(fp);
1984 fp->f_gcflag &= ~FWAIT;
1985 wakeup(&fp->f_gcflag);
1986 FILE_UNLOCK(fp);
1987 }
1988 } while (unp_defer);
1989 sx_sunlock(&filelist_lock);
1990 /*
1991 * XXXRW: The following comments need updating for a post-SMPng and
1992 * deferred unp_gc() world, but are still generally accurate.
1993 *
1994 * We grab an extra reference to each of the file table entries that
1995 * are not otherwise accessible and then free the rights that are
1996 * stored in messages on them.
1997 *
1998 * The bug in the orginal code is a little tricky, so I'll describe
1999 * what's wrong with it here.
2000 *
2001 * It is incorrect to simply unp_discard each entry for f_msgcount
2002 * times -- consider the case of sockets A and B that contain
2003 * references to each other. On a last close of some other socket,
2004 * we trigger a gc since the number of outstanding rights (unp_rights)
2005 * is non-zero. If during the sweep phase the gc code unp_discards,
2006 * we end up doing a (full) closef on the descriptor. A closef on A
2007 * results in the following chain. Closef calls soo_close, which
2008 * calls soclose. Soclose calls first (through the switch
2009 * uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply
2010 * returns because the previous instance had set unp_gcing, and we
2011 * return all the way back to soclose, which marks the socket with
2012 * SS_NOFDREF, and then calls sofree. Sofree calls sorflush to free
2013 * up the rights that are queued in messages on the socket A, i.e.,
2014 * the reference on B. The sorflush calls via the dom_dispose switch
2015 * unp_dispose, which unp_scans with unp_discard. This second
2016 * instance of unp_discard just calls closef on B.
2017 *
2018 * Well, a similar chain occurs on B, resulting in a sorflush on B,
2019 * which results in another closef on A. Unfortunately, A is already
2020 * being closed, and the descriptor has already been marked with
2021 * SS_NOFDREF, and soclose panics at this point.
2022 *
2023 * Here, we first take an extra reference to each inaccessible
2024 * descriptor. Then, we call sorflush ourself, since we know it is a
2025 * Unix domain socket anyhow. After we destroy all the rights
2026 * carried in messages, we do a last closef to get rid of our extra
2027 * reference. This is the last close, and the unp_detach etc will
2028 * shut down the socket.
2029 *
2030 * 91/09/19, bsy@cs.cmu.edu
2031 */
2032 again:
2033 nfiles_snap = openfiles + nfiles_slack; /* some slack */
2034 extra_ref = malloc(nfiles_snap * sizeof(struct file *), M_TEMP,
2035 M_WAITOK);
2036 sx_slock(&filelist_lock);
2037 if (nfiles_snap < openfiles) {
2038 sx_sunlock(&filelist_lock);
2039 free(extra_ref, M_TEMP);
2040 nfiles_slack += 20;
2041 goto again;
2042 }
2043 for (nunref = 0, fp = LIST_FIRST(&filehead), fpp = extra_ref;
2044 fp != NULL; fp = nextfp) {
2045 nextfp = LIST_NEXT(fp, f_list);
2046 FILE_LOCK(fp);
2047 /*
2048 * If it's not open, skip it
2049 */
2050 if (fp->f_count == 0) {
2051 FILE_UNLOCK(fp);
2052 continue;
2053 }
2054 /*
2055 * If all refs are from msgs, and it's not marked accessible
2056 * then it must be referenced from some unreachable cycle of
2057 * (shut-down) FDs, so include it in our list of FDs to
2058 * remove.
2059 */
2060 if (fp->f_count == fp->f_msgcount && !(fp->f_gcflag & FMARK)) {
2061 *fpp++ = fp;
2062 nunref++;
2063 fp->f_count++;
2064 }
2065 FILE_UNLOCK(fp);
2066 }
2067 sx_sunlock(&filelist_lock);
2068 /*
2069 * For each FD on our hit list, do the following two things:
2070 */
2071 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) {
2072 struct file *tfp = *fpp;
2073 FILE_LOCK(tfp);
2074 if (tfp->f_type == DTYPE_SOCKET &&
2075 tfp->f_data != NULL) {
2076 FILE_UNLOCK(tfp);
2077 sorflush(tfp->f_data);
2078 } else {
2079 FILE_UNLOCK(tfp);
2080 }
2081 }
2082 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) {
2083 closef(*fpp, (struct thread *) NULL);
2084 unp_recycled++;
2085 }
2086 free(extra_ref, M_TEMP);
2087 }
2088
2089 void
2090 unp_dispose(struct mbuf *m)
2091 {
2092
2093 if (m)
2094 unp_scan(m, unp_discard);
2095 }
2096
2097 static void
2098 unp_scan(struct mbuf *m0, void (*op)(struct file *))
2099 {
2100 struct mbuf *m;
2101 struct file **rp;
2102 struct cmsghdr *cm;
2103 void *data;
2104 int i;
2105 socklen_t clen, datalen;
2106 int qfds;
2107
2108 while (m0 != NULL) {
2109 for (m = m0; m; m = m->m_next) {
2110 if (m->m_type != MT_CONTROL)
2111 continue;
2112
2113 cm = mtod(m, struct cmsghdr *);
2114 clen = m->m_len;
2115
2116 while (cm != NULL) {
2117 if (sizeof(*cm) > clen || cm->cmsg_len > clen)
2118 break;
2119
2120 data = CMSG_DATA(cm);
2121 datalen = (caddr_t)cm + cm->cmsg_len
2122 - (caddr_t)data;
2123
2124 if (cm->cmsg_level == SOL_SOCKET &&
2125 cm->cmsg_type == SCM_RIGHTS) {
2126 qfds = datalen / sizeof (struct file *);
2127 rp = data;
2128 for (i = 0; i < qfds; i++)
2129 (*op)(*rp++);
2130 }
2131
2132 if (CMSG_SPACE(datalen) < clen) {
2133 clen -= CMSG_SPACE(datalen);
2134 cm = (struct cmsghdr *)
2135 ((caddr_t)cm + CMSG_SPACE(datalen));
2136 } else {
2137 clen = 0;
2138 cm = NULL;
2139 }
2140 }
2141 }
2142 m0 = m0->m_act;
2143 }
2144 }
2145
2146 static void
2147 unp_mark(struct file *fp)
2148 {
2149
2150 /* XXXRW: Should probably assert file list lock here. */
2151
2152 if (fp->f_gcflag & FMARK)
2153 return;
2154 unp_defer++;
2155 fp->f_gcflag |= (FMARK|FDEFER);
2156 }
2157
2158 static void
2159 unp_discard(struct file *fp)
2160 {
2161
2162 UNP_GLOBAL_WLOCK();
2163 FILE_LOCK(fp);
2164 fp->f_msgcount--;
2165 unp_rights--;
2166 FILE_UNLOCK(fp);
2167 UNP_GLOBAL_WUNLOCK();
2168 (void) closef(fp, (struct thread *)NULL);
2169 }
2170
2171 #ifdef DDB
2172 static void
2173 db_print_indent(int indent)
2174 {
2175 int i;
2176
2177 for (i = 0; i < indent; i++)
2178 db_printf(" ");
2179 }
2180
2181 static void
2182 db_print_unpflags(int unp_flags)
2183 {
2184 int comma;
2185
2186 comma = 0;
2187 if (unp_flags & UNP_HAVEPC) {
2188 db_printf("%sUNP_HAVEPC", comma ? ", " : "");
2189 comma = 1;
2190 }
2191 if (unp_flags & UNP_HAVEPCCACHED) {
2192 db_printf("%sUNP_HAVEPCCACHED", comma ? ", " : "");
2193 comma = 1;
2194 }
2195 if (unp_flags & UNP_WANTCRED) {
2196 db_printf("%sUNP_WANTCRED", comma ? ", " : "");
2197 comma = 1;
2198 }
2199 if (unp_flags & UNP_CONNWAIT) {
2200 db_printf("%sUNP_CONNWAIT", comma ? ", " : "");
2201 comma = 1;
2202 }
2203 if (unp_flags & UNP_CONNECTING) {
2204 db_printf("%sUNP_CONNECTING", comma ? ", " : "");
2205 comma = 1;
2206 }
2207 if (unp_flags & UNP_BINDING) {
2208 db_printf("%sUNP_BINDING", comma ? ", " : "");
2209 comma = 1;
2210 }
2211 }
2212
2213 static void
2214 db_print_xucred(int indent, struct xucred *xu)
2215 {
2216 int comma, i;
2217
2218 db_print_indent(indent);
2219 db_printf("cr_version: %u cr_uid: %u cr_ngroups: %d\n",
2220 xu->cr_version, xu->cr_uid, xu->cr_ngroups);
2221 db_print_indent(indent);
2222 db_printf("cr_groups: ");
2223 comma = 0;
2224 for (i = 0; i < xu->cr_ngroups; i++) {
2225 db_printf("%s%u", comma ? ", " : "", xu->cr_groups[i]);
2226 comma = 1;
2227 }
2228 db_printf("\n");
2229 }
2230
2231 static void
2232 db_print_unprefs(int indent, struct unp_head *uh)
2233 {
2234 struct unpcb *unp;
2235 int counter;
2236
2237 counter = 0;
2238 LIST_FOREACH(unp, uh, unp_reflink) {
2239 if (counter % 4 == 0)
2240 db_print_indent(indent);
2241 db_printf("%p ", unp);
2242 if (counter % 4 == 3)
2243 db_printf("\n");
2244 counter++;
2245 }
2246 if (counter != 0 && counter % 4 != 0)
2247 db_printf("\n");
2248 }
2249
2250 DB_SHOW_COMMAND(unpcb, db_show_unpcb)
2251 {
2252 struct unpcb *unp;
2253
2254 if (!have_addr) {
2255 db_printf("usage: show unpcb <addr>\n");
2256 return;
2257 }
2258 unp = (struct unpcb *)addr;
2259
2260 db_printf("unp_socket: %p unp_vnode: %p\n", unp->unp_socket,
2261 unp->unp_vnode);
2262
2263 db_printf("unp_ino: %d unp_conn: %p\n", unp->unp_ino,
2264 unp->unp_conn);
2265
2266 db_printf("unp_refs:\n");
2267 db_print_unprefs(2, &unp->unp_refs);
2268
2269 /* XXXRW: Would be nice to print the full address, if any. */
2270 db_printf("unp_addr: %p\n", unp->unp_addr);
2271
2272 db_printf("unp_cc: %d unp_mbcnt: %d unp_gencnt: %llu\n",
2273 unp->unp_cc, unp->unp_mbcnt,
2274 (unsigned long long)unp->unp_gencnt);
2275
2276 db_printf("unp_flags: %x (", unp->unp_flags);
2277 db_print_unpflags(unp->unp_flags);
2278 db_printf(")\n");
2279
2280 db_printf("unp_peercred:\n");
2281 db_print_xucred(2, &unp->unp_peercred);
2282
2283 db_printf("unp_refcount: %u\n", unp->unp_refcount);
2284 }
2285 #endif
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