xref: /freebsd/sys/compat/linux/linux.c (revision 945a7f0d21a0bcbcce3f308e080f54dfb7da54b1)
1 /*-
2  * Copyright (c) 2015 Dmitry Chagin <dchagin@FreeBSD.org>
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23  * SUCH DAMAGE.
24  */
25 
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
28 
29 #include "opt_inet6.h"
30 
31 #include <sys/param.h>
32 #include <sys/conf.h>
33 #include <sys/ctype.h>
34 #include <sys/file.h>
35 #include <sys/filedesc.h>
36 #include <sys/jail.h>
37 #include <sys/lock.h>
38 #include <sys/malloc.h>
39 #include <sys/poll.h>
40 #include <sys/proc.h>
41 #include <sys/signalvar.h>
42 #include <sys/socket.h>
43 #include <sys/socketvar.h>
44 
45 #include <net/if.h>
46 #include <net/if_var.h>
47 #include <net/if_dl.h>
48 #include <net/if_types.h>
49 #include <netlink/netlink.h>
50 
51 #include <sys/un.h>
52 #include <netinet/in.h>
53 
54 #include <compat/linux/linux.h>
55 #include <compat/linux/linux_common.h>
56 #include <compat/linux/linux_mib.h>
57 #include <compat/linux/linux_util.h>
58 
59 _Static_assert(LINUX_IFNAMSIZ == IFNAMSIZ, "Linux IFNAMSIZ");
60 _Static_assert(sizeof(struct sockaddr) == sizeof(struct l_sockaddr),
61     "Linux struct sockaddr size");
62 _Static_assert(offsetof(struct sockaddr, sa_data) ==
63     offsetof(struct l_sockaddr, sa_data), "Linux struct sockaddr layout");
64 
65 static bool use_real_ifnames = false;
66 SYSCTL_BOOL(_compat_linux, OID_AUTO, use_real_ifnames, CTLFLAG_RWTUN,
67     &use_real_ifnames, 0,
68     "Use FreeBSD interface names instead of generating ethN aliases");
69 
70 static int bsd_to_linux_sigtbl[LINUX_SIGTBLSZ] = {
71 	LINUX_SIGHUP,	/* SIGHUP */
72 	LINUX_SIGINT,	/* SIGINT */
73 	LINUX_SIGQUIT,	/* SIGQUIT */
74 	LINUX_SIGILL,	/* SIGILL */
75 	LINUX_SIGTRAP,	/* SIGTRAP */
76 	LINUX_SIGABRT,	/* SIGABRT */
77 	0,		/* SIGEMT */
78 	LINUX_SIGFPE,	/* SIGFPE */
79 	LINUX_SIGKILL,	/* SIGKILL */
80 	LINUX_SIGBUS,	/* SIGBUS */
81 	LINUX_SIGSEGV,	/* SIGSEGV */
82 	LINUX_SIGSYS,	/* SIGSYS */
83 	LINUX_SIGPIPE,	/* SIGPIPE */
84 	LINUX_SIGALRM,	/* SIGALRM */
85 	LINUX_SIGTERM,	/* SIGTERM */
86 	LINUX_SIGURG,	/* SIGURG */
87 	LINUX_SIGSTOP,	/* SIGSTOP */
88 	LINUX_SIGTSTP,	/* SIGTSTP */
89 	LINUX_SIGCONT,	/* SIGCONT */
90 	LINUX_SIGCHLD,	/* SIGCHLD */
91 	LINUX_SIGTTIN,	/* SIGTTIN */
92 	LINUX_SIGTTOU,	/* SIGTTOU */
93 	LINUX_SIGIO,	/* SIGIO */
94 	LINUX_SIGXCPU,	/* SIGXCPU */
95 	LINUX_SIGXFSZ,	/* SIGXFSZ */
96 	LINUX_SIGVTALRM,/* SIGVTALRM */
97 	LINUX_SIGPROF,	/* SIGPROF */
98 	LINUX_SIGWINCH,	/* SIGWINCH */
99 	0,		/* SIGINFO */
100 	LINUX_SIGUSR1,	/* SIGUSR1 */
101 	LINUX_SIGUSR2	/* SIGUSR2 */
102 };
103 
104 #define	LINUX_SIGPWREMU	(SIGRTMIN + (LINUX_SIGRTMAX - LINUX_SIGRTMIN) + 1)
105 
106 static int linux_to_bsd_sigtbl[LINUX_SIGTBLSZ] = {
107 	SIGHUP,		/* LINUX_SIGHUP */
108 	SIGINT,		/* LINUX_SIGINT */
109 	SIGQUIT,	/* LINUX_SIGQUIT */
110 	SIGILL,		/* LINUX_SIGILL */
111 	SIGTRAP,	/* LINUX_SIGTRAP */
112 	SIGABRT,	/* LINUX_SIGABRT */
113 	SIGBUS,		/* LINUX_SIGBUS */
114 	SIGFPE,		/* LINUX_SIGFPE */
115 	SIGKILL,	/* LINUX_SIGKILL */
116 	SIGUSR1,	/* LINUX_SIGUSR1 */
117 	SIGSEGV,	/* LINUX_SIGSEGV */
118 	SIGUSR2,	/* LINUX_SIGUSR2 */
119 	SIGPIPE,	/* LINUX_SIGPIPE */
120 	SIGALRM,	/* LINUX_SIGALRM */
121 	SIGTERM,	/* LINUX_SIGTERM */
122 	SIGBUS,		/* LINUX_SIGSTKFLT */
123 	SIGCHLD,	/* LINUX_SIGCHLD */
124 	SIGCONT,	/* LINUX_SIGCONT */
125 	SIGSTOP,	/* LINUX_SIGSTOP */
126 	SIGTSTP,	/* LINUX_SIGTSTP */
127 	SIGTTIN,	/* LINUX_SIGTTIN */
128 	SIGTTOU,	/* LINUX_SIGTTOU */
129 	SIGURG,		/* LINUX_SIGURG */
130 	SIGXCPU,	/* LINUX_SIGXCPU */
131 	SIGXFSZ,	/* LINUX_SIGXFSZ */
132 	SIGVTALRM,	/* LINUX_SIGVTALARM */
133 	SIGPROF,	/* LINUX_SIGPROF */
134 	SIGWINCH,	/* LINUX_SIGWINCH */
135 	SIGIO,		/* LINUX_SIGIO */
136 	/*
137 	 * FreeBSD does not have SIGPWR signal, map Linux SIGPWR signal
138 	 * to the first unused FreeBSD signal number. Since Linux supports
139 	 * signals from 1 to 64 we are ok here as our SIGRTMIN = 65.
140 	 */
141 	LINUX_SIGPWREMU,/* LINUX_SIGPWR */
142 	SIGSYS		/* LINUX_SIGSYS */
143 };
144 
145 static struct cdev *dev_shm_cdev;
146 static struct cdevsw dev_shm_cdevsw = {
147      .d_version = D_VERSION,
148      .d_name    = "dev_shm",
149 };
150 
151 /*
152  * Map Linux RT signals to the FreeBSD RT signals.
153  */
154 static inline int
155 linux_to_bsd_rt_signal(int sig)
156 {
157 
158 	return (SIGRTMIN + sig - LINUX_SIGRTMIN);
159 }
160 
161 static inline int
162 bsd_to_linux_rt_signal(int sig)
163 {
164 
165 	return (sig - SIGRTMIN + LINUX_SIGRTMIN);
166 }
167 
168 int
169 linux_to_bsd_signal(int sig)
170 {
171 
172 	KASSERT(sig > 0 && sig <= LINUX_SIGRTMAX, ("invalid Linux signal %d\n", sig));
173 
174 	if (sig < LINUX_SIGRTMIN)
175 		return (linux_to_bsd_sigtbl[_SIG_IDX(sig)]);
176 
177 	return (linux_to_bsd_rt_signal(sig));
178 }
179 
180 int
181 bsd_to_linux_signal(int sig)
182 {
183 
184 	if (sig <= LINUX_SIGTBLSZ)
185 		return (bsd_to_linux_sigtbl[_SIG_IDX(sig)]);
186 	if (sig == LINUX_SIGPWREMU)
187 		return (LINUX_SIGPWR);
188 
189 	return (bsd_to_linux_rt_signal(sig));
190 }
191 
192 int
193 linux_to_bsd_sigaltstack(int lsa)
194 {
195 	int bsa = 0;
196 
197 	if (lsa & LINUX_SS_DISABLE)
198 		bsa |= SS_DISABLE;
199 	/*
200 	 * Linux ignores SS_ONSTACK flag for ss
201 	 * parameter while FreeBSD prohibits it.
202 	 */
203 	return (bsa);
204 }
205 
206 int
207 bsd_to_linux_sigaltstack(int bsa)
208 {
209 	int lsa = 0;
210 
211 	if (bsa & SS_DISABLE)
212 		lsa |= LINUX_SS_DISABLE;
213 	if (bsa & SS_ONSTACK)
214 		lsa |= LINUX_SS_ONSTACK;
215 	return (lsa);
216 }
217 
218 void
219 linux_to_bsd_sigset(l_sigset_t *lss, sigset_t *bss)
220 {
221 	int b, l;
222 
223 	SIGEMPTYSET(*bss);
224 	for (l = 1; l <= LINUX_SIGRTMAX; l++) {
225 		if (LINUX_SIGISMEMBER(*lss, l)) {
226 			b = linux_to_bsd_signal(l);
227 			if (b)
228 				SIGADDSET(*bss, b);
229 		}
230 	}
231 }
232 
233 void
234 bsd_to_linux_sigset(sigset_t *bss, l_sigset_t *lss)
235 {
236 	int b, l;
237 
238 	LINUX_SIGEMPTYSET(*lss);
239 	for (b = 1; b <= SIGRTMAX; b++) {
240 		if (SIGISMEMBER(*bss, b)) {
241 			l = bsd_to_linux_signal(b);
242 			if (l)
243 				LINUX_SIGADDSET(*lss, l);
244 		}
245 	}
246 }
247 
248 /*
249  * Translate a FreeBSD interface name to a Linux interface name
250  * by interface name, and return the number of bytes copied to lxname.
251  */
252 int
253 ifname_bsd_to_linux_name(const char *bsdname, char *lxname, size_t len)
254 {
255 	struct epoch_tracker et;
256 	struct ifnet *ifp;
257 	int ret;
258 
259 	ret = 0;
260 	CURVNET_SET(TD_TO_VNET(curthread));
261 	NET_EPOCH_ENTER(et);
262 	ifp = ifunit(bsdname);
263 	if (ifp != NULL)
264 		ret = ifname_bsd_to_linux_ifp(ifp, lxname, len);
265 	NET_EPOCH_EXIT(et);
266 	CURVNET_RESTORE();
267 	return (ret);
268 }
269 
270 /*
271  * Translate a FreeBSD interface name to a Linux interface name
272  * by interface index, and return the number of bytes copied to lxname.
273  */
274 int
275 ifname_bsd_to_linux_idx(u_int idx, char *lxname, size_t len)
276 {
277 	struct epoch_tracker et;
278 	struct ifnet *ifp;
279 	int ret;
280 
281 	ret = 0;
282 	CURVNET_SET(TD_TO_VNET(curthread));
283 	NET_EPOCH_ENTER(et);
284 	ifp = ifnet_byindex(idx);
285 	if (ifp != NULL)
286 		ret = ifname_bsd_to_linux_ifp(ifp, lxname, len);
287 	NET_EPOCH_EXIT(et);
288 	CURVNET_RESTORE();
289 	return (ret);
290 }
291 
292 /*
293  * Translate a FreeBSD interface name to a Linux interface name,
294  * and return the number of bytes copied to lxname, 0 if interface
295  * not found, -1 on error.
296  */
297 struct ifname_bsd_to_linux_ifp_cb_s {
298 	struct ifnet	*ifp;
299 	int		ethno;
300 	char		*lxname;
301 	size_t		len;
302 };
303 
304 static int
305 ifname_bsd_to_linux_ifp_cb(if_t ifp, void *arg)
306 {
307 	struct ifname_bsd_to_linux_ifp_cb_s *cbs = arg;
308 
309 	if (ifp == cbs->ifp)
310 		return (snprintf(cbs->lxname, cbs->len, "eth%d", cbs->ethno));
311 	if (IFP_IS_ETH(ifp))
312 		cbs->ethno++;
313 	return (0);
314 }
315 
316 int
317 ifname_bsd_to_linux_ifp(struct ifnet *ifp, char *lxname, size_t len)
318 {
319 	struct ifname_bsd_to_linux_ifp_cb_s arg = {
320 		.ifp = ifp,
321 		.ethno = 0,
322 		.lxname = lxname,
323 		.len = len,
324 	};
325 
326 	NET_EPOCH_ASSERT();
327 
328 	/*
329 	 * Linux loopback interface name is lo (not lo0),
330 	 * we translate lo to lo0, loX to loX.
331 	 */
332 	if (IFP_IS_LOOP(ifp) && strncmp(ifp->if_xname, "lo0", IFNAMSIZ) == 0)
333 		return (strlcpy(lxname, "lo", len));
334 
335 	/* Short-circuit non ethernet interfaces. */
336 	if (!IFP_IS_ETH(ifp) || linux_use_real_ifname(ifp))
337 		return (strlcpy(lxname, if_name(ifp), len));
338 
339  	/* Determine the (relative) unit number for ethernet interfaces. */
340 	return (if_foreach(ifname_bsd_to_linux_ifp_cb, &arg));
341 }
342 
343 /*
344  * Translate a Linux interface name to a FreeBSD interface name,
345  * and return the associated ifnet structure
346  * bsdname and lxname need to be least IFNAMSIZ bytes long, but
347  * can point to the same buffer.
348  */
349 struct ifname_linux_to_ifp_cb_s {
350 	bool		is_lo;
351 	bool		is_eth;
352 	int		ethno;
353 	int		unit;
354 	const char	*lxname;
355 	if_t		ifp;
356 };
357 
358 static int
359 ifname_linux_to_ifp_cb(if_t ifp, void *arg)
360 {
361 	struct ifname_linux_to_ifp_cb_s *cbs = arg;
362 
363 	NET_EPOCH_ASSERT();
364 
365 	/*
366 	 * Allow Linux programs to use FreeBSD names. Don't presume
367 	 * we never have an interface named "eth", so don't make
368 	 * the test optional based on is_eth.
369 	 */
370 	if (strncmp(if_name(ifp), cbs->lxname, LINUX_IFNAMSIZ) == 0)
371 		goto out;
372 	if (cbs->is_eth && IFP_IS_ETH(ifp) && cbs->unit == cbs->ethno)
373 		goto out;
374 	if (cbs->is_lo && IFP_IS_LOOP(ifp))
375 		goto out;
376 	if (IFP_IS_ETH(ifp))
377 		cbs->ethno++;
378 	return (0);
379 
380 out:
381 	cbs->ifp = ifp;
382 	return (1);
383 }
384 
385 struct ifnet *
386 ifname_linux_to_ifp(struct thread *td, const char *lxname)
387 {
388 	struct ifname_linux_to_ifp_cb_s arg = {
389 		.ethno = 0,
390 		.lxname = lxname,
391 		.ifp = NULL,
392 	};
393 	int len;
394 	char *ep;
395 
396 	NET_EPOCH_ASSERT();
397 
398 	for (len = 0; len < LINUX_IFNAMSIZ; ++len)
399 		if (!isalpha(lxname[len]) || lxname[len] == '\0')
400 			break;
401 	if (len == 0 || len == LINUX_IFNAMSIZ)
402 		return (NULL);
403 	/*
404 	 * Linux loopback interface name is lo (not lo0),
405 	 * we translate lo to lo0, loX to loX.
406 	 */
407 	arg.is_lo = (len == 2 && strncmp(lxname, "lo", LINUX_IFNAMSIZ) == 0);
408 	arg.unit = (int)strtoul(lxname + len, &ep, 10);
409 	if ((ep == NULL || ep == lxname + len || ep >= lxname + LINUX_IFNAMSIZ) &&
410 	    arg.is_lo == 0)
411 		return (NULL);
412 	arg.is_eth = (len == 3 && strncmp(lxname, "eth", len) == 0);
413 
414 	if_foreach(ifname_linux_to_ifp_cb, &arg);
415 	return (arg.ifp);
416 }
417 
418 int
419 ifname_linux_to_bsd(struct thread *td, const char *lxname, char *bsdname)
420 {
421 	struct epoch_tracker et;
422 	struct ifnet *ifp;
423 
424 	CURVNET_SET(TD_TO_VNET(td));
425 	NET_EPOCH_ENTER(et);
426 	ifp = ifname_linux_to_ifp(td, lxname);
427 	if (ifp != NULL && bsdname != NULL)
428 		strlcpy(bsdname, if_name(ifp), IFNAMSIZ);
429 	NET_EPOCH_EXIT(et);
430 	CURVNET_RESTORE();
431 	return (ifp != NULL ? 0 : EINVAL);
432 }
433 
434 unsigned short
435 linux_ifflags(struct ifnet *ifp)
436 {
437 	unsigned short fl, flags;
438 
439 	fl = (if_getflags(ifp) | if_getdrvflags(ifp)) & 0xffff;
440 	flags = 0;
441 	if (fl & IFF_UP)
442 		flags |= LINUX_IFF_UP;
443 	if (fl & IFF_BROADCAST)
444 		flags |= LINUX_IFF_BROADCAST;
445 	if (fl & IFF_DEBUG)
446 		flags |= LINUX_IFF_DEBUG;
447 	if (fl & IFF_LOOPBACK)
448 		flags |= LINUX_IFF_LOOPBACK;
449 	if (fl & IFF_POINTOPOINT)
450 		flags |= LINUX_IFF_POINTOPOINT;
451 	if (fl & IFF_DRV_RUNNING)
452 		flags |= LINUX_IFF_RUNNING;
453 	if (fl & IFF_NOARP)
454 		flags |= LINUX_IFF_NOARP;
455 	if (fl & IFF_PROMISC)
456 		flags |= LINUX_IFF_PROMISC;
457 	if (fl & IFF_ALLMULTI)
458 		flags |= LINUX_IFF_ALLMULTI;
459 	if (fl & IFF_MULTICAST)
460 		flags |= LINUX_IFF_MULTICAST;
461 	return (flags);
462 }
463 
464 static u_int
465 linux_ifhwaddr_cb(void *arg, struct ifaddr *ifa, u_int count)
466 {
467 	struct sockaddr_dl *sdl = (struct sockaddr_dl *)ifa->ifa_addr;
468 	struct l_sockaddr *lsa = arg;
469 
470 	if (count > 0)
471 		return (0);
472 	if (sdl->sdl_type != IFT_ETHER)
473 		return (0);
474 	bzero(lsa, sizeof(*lsa));
475 	lsa->sa_family = LINUX_ARPHRD_ETHER;
476 	bcopy(LLADDR(sdl), lsa->sa_data, LINUX_IFHWADDRLEN);
477 	return (1);
478 }
479 
480 int
481 linux_ifhwaddr(struct ifnet *ifp, struct l_sockaddr *lsa)
482 {
483 
484 	NET_EPOCH_ASSERT();
485 
486 	if (IFP_IS_LOOP(ifp)) {
487 		bzero(lsa, sizeof(*lsa));
488 		lsa->sa_family = LINUX_ARPHRD_LOOPBACK;
489 		return (0);
490 	}
491 	if (!IFP_IS_ETH(ifp))
492 		return (ENOENT);
493 	if (if_foreach_addr_type(ifp, AF_LINK, linux_ifhwaddr_cb, lsa) > 0)
494 		return (0);
495 	return (ENOENT);
496 }
497 
498 int
499 linux_to_bsd_domain(int domain)
500 {
501 
502 	switch (domain) {
503 	case LINUX_AF_UNSPEC:
504 		return (AF_UNSPEC);
505 	case LINUX_AF_UNIX:
506 		return (AF_LOCAL);
507 	case LINUX_AF_INET:
508 		return (AF_INET);
509 	case LINUX_AF_INET6:
510 		return (AF_INET6);
511 	case LINUX_AF_AX25:
512 		return (AF_CCITT);
513 	case LINUX_AF_IPX:
514 		return (AF_IPX);
515 	case LINUX_AF_APPLETALK:
516 		return (AF_APPLETALK);
517 	case LINUX_AF_NETLINK:
518 		return (AF_NETLINK);
519 	}
520 	return (-1);
521 }
522 
523 int
524 bsd_to_linux_domain(int domain)
525 {
526 
527 	switch (domain) {
528 	case AF_UNSPEC:
529 		return (LINUX_AF_UNSPEC);
530 	case AF_LOCAL:
531 		return (LINUX_AF_UNIX);
532 	case AF_INET:
533 		return (LINUX_AF_INET);
534 	case AF_INET6:
535 		return (LINUX_AF_INET6);
536 	case AF_CCITT:
537 		return (LINUX_AF_AX25);
538 	case AF_IPX:
539 		return (LINUX_AF_IPX);
540 	case AF_APPLETALK:
541 		return (LINUX_AF_APPLETALK);
542 	case AF_NETLINK:
543 		return (LINUX_AF_NETLINK);
544 	}
545 	return (-1);
546 }
547 
548 /*
549  * Based on the fact that:
550  * 1. Native and Linux storage of struct sockaddr
551  * and struct sockaddr_in6 are equal.
552  * 2. On Linux sa_family is the first member of all struct sockaddr.
553  */
554 int
555 bsd_to_linux_sockaddr(const struct sockaddr *sa, struct l_sockaddr **lsa,
556     socklen_t len)
557 {
558 	struct l_sockaddr *kosa;
559 	int bdom;
560 
561 	*lsa = NULL;
562 	if (len < 2 || len > UCHAR_MAX)
563 		return (EINVAL);
564 	bdom = bsd_to_linux_domain(sa->sa_family);
565 	if (bdom == -1)
566 		return (EAFNOSUPPORT);
567 
568 	kosa = malloc(len, M_LINUX, M_WAITOK);
569 	bcopy(sa, kosa, len);
570 	kosa->sa_family = bdom;
571 	*lsa = kosa;
572 	return (0);
573 }
574 
575 int
576 linux_to_bsd_sockaddr(const struct l_sockaddr *osa, struct sockaddr **sap,
577     socklen_t *len)
578 {
579 	struct sockaddr *sa;
580 	struct l_sockaddr *kosa;
581 #ifdef INET6
582 	struct sockaddr_in6 *sin6;
583 	bool  oldv6size;
584 #endif
585 	char *name;
586 	int salen, bdom, error, hdrlen, namelen;
587 
588 	if (*len < 2 || *len > UCHAR_MAX)
589 		return (EINVAL);
590 
591 	salen = *len;
592 
593 #ifdef INET6
594 	oldv6size = false;
595 	/*
596 	 * Check for old (pre-RFC2553) sockaddr_in6. We may accept it
597 	 * if it's a v4-mapped address, so reserve the proper space
598 	 * for it.
599 	 */
600 	if (salen == sizeof(struct sockaddr_in6) - sizeof(uint32_t)) {
601 		salen += sizeof(uint32_t);
602 		oldv6size = true;
603 	}
604 #endif
605 
606 	kosa = malloc(salen, M_SONAME, M_WAITOK);
607 
608 	if ((error = copyin(osa, kosa, *len)))
609 		goto out;
610 
611 	bdom = linux_to_bsd_domain(kosa->sa_family);
612 	if (bdom == -1) {
613 		error = EAFNOSUPPORT;
614 		goto out;
615 	}
616 
617 #ifdef INET6
618 	/*
619 	 * Older Linux IPv6 code uses obsolete RFC2133 struct sockaddr_in6,
620 	 * which lacks the scope id compared with RFC2553 one. If we detect
621 	 * the situation, reject the address and write a message to system log.
622 	 *
623 	 * Still accept addresses for which the scope id is not used.
624 	 */
625 	if (oldv6size) {
626 		if (bdom == AF_INET6) {
627 			sin6 = (struct sockaddr_in6 *)kosa;
628 			if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr) ||
629 			    (!IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr) &&
630 			     !IN6_IS_ADDR_SITELOCAL(&sin6->sin6_addr) &&
631 			     !IN6_IS_ADDR_V4COMPAT(&sin6->sin6_addr) &&
632 			     !IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr) &&
633 			     !IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))) {
634 				sin6->sin6_scope_id = 0;
635 			} else {
636 				linux_msg(curthread,
637 				    "obsolete pre-RFC2553 sockaddr_in6 rejected");
638 				error = EINVAL;
639 				goto out;
640 			}
641 		} else
642 			salen -= sizeof(uint32_t);
643 	}
644 #endif
645 	if (bdom == AF_INET) {
646 		if (salen < sizeof(struct sockaddr_in)) {
647 			error = EINVAL;
648 			goto out;
649 		}
650 		salen = sizeof(struct sockaddr_in);
651 	}
652 
653 	if (bdom == AF_LOCAL && salen > sizeof(struct sockaddr_un)) {
654 		hdrlen = offsetof(struct sockaddr_un, sun_path);
655 		name = ((struct sockaddr_un *)kosa)->sun_path;
656 		if (*name == '\0') {
657 			/*
658 			 * Linux abstract namespace starts with a NULL byte.
659 			 * XXX We do not support abstract namespace yet.
660 			 */
661 			namelen = strnlen(name + 1, salen - hdrlen - 1) + 1;
662 		} else
663 			namelen = strnlen(name, salen - hdrlen);
664 		salen = hdrlen + namelen;
665 		if (salen > sizeof(struct sockaddr_un)) {
666 			error = ENAMETOOLONG;
667 			goto out;
668 		}
669 	}
670 
671 	if (bdom == AF_NETLINK) {
672 		if (salen < sizeof(struct sockaddr_nl)) {
673 			error = EINVAL;
674 			goto out;
675 		}
676 		salen = sizeof(struct sockaddr_nl);
677 	}
678 
679 	sa = (struct sockaddr *)kosa;
680 	sa->sa_family = bdom;
681 	sa->sa_len = salen;
682 
683 	*sap = sa;
684 	*len = salen;
685 	return (0);
686 
687 out:
688 	free(kosa, M_SONAME);
689 	return (error);
690 }
691 
692 void
693 linux_dev_shm_create(void)
694 {
695 	int error;
696 
697 	error = make_dev_p(MAKEDEV_CHECKNAME | MAKEDEV_WAITOK, &dev_shm_cdev,
698 	    &dev_shm_cdevsw, NULL, UID_ROOT, GID_WHEEL, 0, "shm/.mountpoint");
699 	if (error != 0) {
700 		printf("%s: failed to create device node, error %d\n",
701 		    __func__, error);
702 	}
703 }
704 
705 void
706 linux_dev_shm_destroy(void)
707 {
708 
709 	destroy_dev(dev_shm_cdev);
710 }
711 
712 int
713 bsd_to_linux_bits_(int value, struct bsd_to_linux_bitmap *bitmap,
714     size_t mapcnt, int no_value)
715 {
716 	int bsd_mask, bsd_value, linux_mask, linux_value;
717 	int linux_ret;
718 	size_t i;
719 	bool applied;
720 
721 	applied = false;
722 	linux_ret = 0;
723 	for (i = 0; i < mapcnt; ++i) {
724 		bsd_mask = bitmap[i].bsd_mask;
725 		bsd_value = bitmap[i].bsd_value;
726 		if (bsd_mask == 0)
727 			bsd_mask = bsd_value;
728 
729 		linux_mask = bitmap[i].linux_mask;
730 		linux_value = bitmap[i].linux_value;
731 		if (linux_mask == 0)
732 			linux_mask = linux_value;
733 
734 		/*
735 		 * If a mask larger than just the value is set, we explicitly
736 		 * want to make sure that only this bit we mapped within that
737 		 * mask is set.
738 		 */
739 		if ((value & bsd_mask) == bsd_value) {
740 			linux_ret = (linux_ret & ~linux_mask) | linux_value;
741 			applied = true;
742 		}
743 	}
744 
745 	if (!applied)
746 		return (no_value);
747 	return (linux_ret);
748 }
749 
750 int
751 linux_to_bsd_bits_(int value, struct bsd_to_linux_bitmap *bitmap,
752     size_t mapcnt, int no_value)
753 {
754 	int bsd_mask, bsd_value, linux_mask, linux_value;
755 	int bsd_ret;
756 	size_t i;
757 	bool applied;
758 
759 	applied = false;
760 	bsd_ret = 0;
761 	for (i = 0; i < mapcnt; ++i) {
762 		bsd_mask = bitmap[i].bsd_mask;
763 		bsd_value = bitmap[i].bsd_value;
764 		if (bsd_mask == 0)
765 			bsd_mask = bsd_value;
766 
767 		linux_mask = bitmap[i].linux_mask;
768 		linux_value = bitmap[i].linux_value;
769 		if (linux_mask == 0)
770 			linux_mask = linux_value;
771 
772 		/*
773 		 * If a mask larger than just the value is set, we explicitly
774 		 * want to make sure that only this bit we mapped within that
775 		 * mask is set.
776 		 */
777 		if ((value & linux_mask) == linux_value) {
778 			bsd_ret = (bsd_ret & ~bsd_mask) | bsd_value;
779 			applied = true;
780 		}
781 	}
782 
783 	if (!applied)
784 		return (no_value);
785 	return (bsd_ret);
786 }
787 
788 void
789 linux_to_bsd_poll_events(struct thread *td, int fd, short lev,
790     short *bev)
791 {
792 	struct file *fp;
793 	int error;
794 	short bits = 0;
795 
796 	if (lev & LINUX_POLLIN)
797 		bits |= POLLIN;
798 	if (lev & LINUX_POLLPRI)
799 		bits |=	POLLPRI;
800 	if (lev & LINUX_POLLOUT)
801 		bits |= POLLOUT;
802 	if (lev & LINUX_POLLERR)
803 		bits |= POLLERR;
804 	if (lev & LINUX_POLLHUP)
805 		bits |= POLLHUP;
806 	if (lev & LINUX_POLLNVAL)
807 		bits |= POLLNVAL;
808 	if (lev & LINUX_POLLRDNORM)
809 		bits |= POLLRDNORM;
810 	if (lev & LINUX_POLLRDBAND)
811 		bits |= POLLRDBAND;
812 	if (lev & LINUX_POLLWRBAND)
813 		bits |= POLLWRBAND;
814 	if (lev & LINUX_POLLWRNORM)
815 		bits |= POLLWRNORM;
816 
817 	if (lev & LINUX_POLLRDHUP) {
818 		/*
819 		 * It seems that the Linux silencly ignores POLLRDHUP
820 		 * on non-socket file descriptors unlike FreeBSD, where
821 		 * events bits is more strictly checked (POLLSTANDARD).
822 		 */
823 		error = fget_unlocked(td, fd, &cap_no_rights, &fp);
824 		if (error == 0) {
825 			/*
826 			 * XXX. On FreeBSD POLLRDHUP applies only to
827 			 * stream sockets.
828 			 */
829 			if (fp->f_type == DTYPE_SOCKET)
830 				bits |= POLLRDHUP;
831 			fdrop(fp, td);
832 		}
833 	}
834 
835 	if (lev & LINUX_POLLMSG)
836 		LINUX_RATELIMIT_MSG_OPT1("unsupported POLLMSG, events(%d)", lev);
837 	if (lev & LINUX_POLLREMOVE)
838 		LINUX_RATELIMIT_MSG_OPT1("unsupported POLLREMOVE, events(%d)", lev);
839 
840 	*bev = bits;
841 }
842 
843 void
844 bsd_to_linux_poll_events(short bev, short *lev)
845 {
846 	short bits = 0;
847 
848 	if (bev & POLLIN)
849 		bits |= LINUX_POLLIN;
850 	if (bev & POLLPRI)
851 		bits |=	LINUX_POLLPRI;
852 	if (bev & (POLLOUT | POLLWRNORM))
853 		/*
854 		 * POLLWRNORM is equal to POLLOUT on FreeBSD,
855 		 * but not on Linux
856 		 */
857 		bits |= LINUX_POLLOUT;
858 	if (bev & POLLERR)
859 		bits |= LINUX_POLLERR;
860 	if (bev & POLLHUP)
861 		bits |= LINUX_POLLHUP;
862 	if (bev & POLLNVAL)
863 		bits |= LINUX_POLLNVAL;
864 	if (bev & POLLRDNORM)
865 		bits |= LINUX_POLLRDNORM;
866 	if (bev & POLLRDBAND)
867 		bits |= LINUX_POLLRDBAND;
868 	if (bev & POLLWRBAND)
869 		bits |= LINUX_POLLWRBAND;
870 	if (bev & POLLRDHUP)
871 		bits |= LINUX_POLLRDHUP;
872 
873 	*lev = bits;
874 }
875 
876 bool
877 linux_use_real_ifname(const struct ifnet *ifp)
878 {
879 
880 	return (use_real_ifnames);
881 }
882