xref: /freebsd/sys/compat/linux/linux.c (revision ee97f198b42d50437f87aa4111d478eca2a5be16)
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 CTASSERT(LINUX_IFNAMSIZ == IFNAMSIZ);
60 
61 static bool use_real_ifnames = false;
62 SYSCTL_BOOL(_compat_linux, OID_AUTO, use_real_ifnames, CTLFLAG_RWTUN,
63     &use_real_ifnames, 0,
64     "Use FreeBSD interface names instead of generating ethN aliases");
65 
66 static int bsd_to_linux_sigtbl[LINUX_SIGTBLSZ] = {
67 	LINUX_SIGHUP,	/* SIGHUP */
68 	LINUX_SIGINT,	/* SIGINT */
69 	LINUX_SIGQUIT,	/* SIGQUIT */
70 	LINUX_SIGILL,	/* SIGILL */
71 	LINUX_SIGTRAP,	/* SIGTRAP */
72 	LINUX_SIGABRT,	/* SIGABRT */
73 	0,		/* SIGEMT */
74 	LINUX_SIGFPE,	/* SIGFPE */
75 	LINUX_SIGKILL,	/* SIGKILL */
76 	LINUX_SIGBUS,	/* SIGBUS */
77 	LINUX_SIGSEGV,	/* SIGSEGV */
78 	LINUX_SIGSYS,	/* SIGSYS */
79 	LINUX_SIGPIPE,	/* SIGPIPE */
80 	LINUX_SIGALRM,	/* SIGALRM */
81 	LINUX_SIGTERM,	/* SIGTERM */
82 	LINUX_SIGURG,	/* SIGURG */
83 	LINUX_SIGSTOP,	/* SIGSTOP */
84 	LINUX_SIGTSTP,	/* SIGTSTP */
85 	LINUX_SIGCONT,	/* SIGCONT */
86 	LINUX_SIGCHLD,	/* SIGCHLD */
87 	LINUX_SIGTTIN,	/* SIGTTIN */
88 	LINUX_SIGTTOU,	/* SIGTTOU */
89 	LINUX_SIGIO,	/* SIGIO */
90 	LINUX_SIGXCPU,	/* SIGXCPU */
91 	LINUX_SIGXFSZ,	/* SIGXFSZ */
92 	LINUX_SIGVTALRM,/* SIGVTALRM */
93 	LINUX_SIGPROF,	/* SIGPROF */
94 	LINUX_SIGWINCH,	/* SIGWINCH */
95 	0,		/* SIGINFO */
96 	LINUX_SIGUSR1,	/* SIGUSR1 */
97 	LINUX_SIGUSR2	/* SIGUSR2 */
98 };
99 
100 #define	LINUX_SIGPWREMU	(SIGRTMIN + (LINUX_SIGRTMAX - LINUX_SIGRTMIN) + 1)
101 
102 static int linux_to_bsd_sigtbl[LINUX_SIGTBLSZ] = {
103 	SIGHUP,		/* LINUX_SIGHUP */
104 	SIGINT,		/* LINUX_SIGINT */
105 	SIGQUIT,	/* LINUX_SIGQUIT */
106 	SIGILL,		/* LINUX_SIGILL */
107 	SIGTRAP,	/* LINUX_SIGTRAP */
108 	SIGABRT,	/* LINUX_SIGABRT */
109 	SIGBUS,		/* LINUX_SIGBUS */
110 	SIGFPE,		/* LINUX_SIGFPE */
111 	SIGKILL,	/* LINUX_SIGKILL */
112 	SIGUSR1,	/* LINUX_SIGUSR1 */
113 	SIGSEGV,	/* LINUX_SIGSEGV */
114 	SIGUSR2,	/* LINUX_SIGUSR2 */
115 	SIGPIPE,	/* LINUX_SIGPIPE */
116 	SIGALRM,	/* LINUX_SIGALRM */
117 	SIGTERM,	/* LINUX_SIGTERM */
118 	SIGBUS,		/* LINUX_SIGSTKFLT */
119 	SIGCHLD,	/* LINUX_SIGCHLD */
120 	SIGCONT,	/* LINUX_SIGCONT */
121 	SIGSTOP,	/* LINUX_SIGSTOP */
122 	SIGTSTP,	/* LINUX_SIGTSTP */
123 	SIGTTIN,	/* LINUX_SIGTTIN */
124 	SIGTTOU,	/* LINUX_SIGTTOU */
125 	SIGURG,		/* LINUX_SIGURG */
126 	SIGXCPU,	/* LINUX_SIGXCPU */
127 	SIGXFSZ,	/* LINUX_SIGXFSZ */
128 	SIGVTALRM,	/* LINUX_SIGVTALARM */
129 	SIGPROF,	/* LINUX_SIGPROF */
130 	SIGWINCH,	/* LINUX_SIGWINCH */
131 	SIGIO,		/* LINUX_SIGIO */
132 	/*
133 	 * FreeBSD does not have SIGPWR signal, map Linux SIGPWR signal
134 	 * to the first unused FreeBSD signal number. Since Linux supports
135 	 * signals from 1 to 64 we are ok here as our SIGRTMIN = 65.
136 	 */
137 	LINUX_SIGPWREMU,/* LINUX_SIGPWR */
138 	SIGSYS		/* LINUX_SIGSYS */
139 };
140 
141 static struct cdev *dev_shm_cdev;
142 static struct cdevsw dev_shm_cdevsw = {
143      .d_version = D_VERSION,
144      .d_name    = "dev_shm",
145 };
146 
147 /*
148  * Map Linux RT signals to the FreeBSD RT signals.
149  */
150 static inline int
151 linux_to_bsd_rt_signal(int sig)
152 {
153 
154 	return (SIGRTMIN + sig - LINUX_SIGRTMIN);
155 }
156 
157 static inline int
158 bsd_to_linux_rt_signal(int sig)
159 {
160 
161 	return (sig - SIGRTMIN + LINUX_SIGRTMIN);
162 }
163 
164 int
165 linux_to_bsd_signal(int sig)
166 {
167 
168 	KASSERT(sig > 0 && sig <= LINUX_SIGRTMAX, ("invalid Linux signal %d\n", sig));
169 
170 	if (sig < LINUX_SIGRTMIN)
171 		return (linux_to_bsd_sigtbl[_SIG_IDX(sig)]);
172 
173 	return (linux_to_bsd_rt_signal(sig));
174 }
175 
176 int
177 bsd_to_linux_signal(int sig)
178 {
179 
180 	if (sig <= LINUX_SIGTBLSZ)
181 		return (bsd_to_linux_sigtbl[_SIG_IDX(sig)]);
182 	if (sig == LINUX_SIGPWREMU)
183 		return (LINUX_SIGPWR);
184 
185 	return (bsd_to_linux_rt_signal(sig));
186 }
187 
188 int
189 linux_to_bsd_sigaltstack(int lsa)
190 {
191 	int bsa = 0;
192 
193 	if (lsa & LINUX_SS_DISABLE)
194 		bsa |= SS_DISABLE;
195 	/*
196 	 * Linux ignores SS_ONSTACK flag for ss
197 	 * parameter while FreeBSD prohibits it.
198 	 */
199 	return (bsa);
200 }
201 
202 int
203 bsd_to_linux_sigaltstack(int bsa)
204 {
205 	int lsa = 0;
206 
207 	if (bsa & SS_DISABLE)
208 		lsa |= LINUX_SS_DISABLE;
209 	if (bsa & SS_ONSTACK)
210 		lsa |= LINUX_SS_ONSTACK;
211 	return (lsa);
212 }
213 
214 void
215 linux_to_bsd_sigset(l_sigset_t *lss, sigset_t *bss)
216 {
217 	int b, l;
218 
219 	SIGEMPTYSET(*bss);
220 	for (l = 1; l <= LINUX_SIGRTMAX; l++) {
221 		if (LINUX_SIGISMEMBER(*lss, l)) {
222 			b = linux_to_bsd_signal(l);
223 			if (b)
224 				SIGADDSET(*bss, b);
225 		}
226 	}
227 }
228 
229 void
230 bsd_to_linux_sigset(sigset_t *bss, l_sigset_t *lss)
231 {
232 	int b, l;
233 
234 	LINUX_SIGEMPTYSET(*lss);
235 	for (b = 1; b <= SIGRTMAX; b++) {
236 		if (SIGISMEMBER(*bss, b)) {
237 			l = bsd_to_linux_signal(b);
238 			if (l)
239 				LINUX_SIGADDSET(*lss, l);
240 		}
241 	}
242 }
243 
244 /*
245  * Translate a Linux interface name to a FreeBSD interface name,
246  * and return the associated ifnet structure
247  * bsdname and lxname need to be least IFNAMSIZ bytes long, but
248  * can point to the same buffer.
249  */
250 struct ifnet *
251 ifname_linux_to_bsd(struct thread *td, const char *lxname, char *bsdname)
252 {
253 	struct ifnet *ifp;
254 	int len, unit;
255 	char *ep;
256 	int index;
257 	bool is_eth, is_lo;
258 
259 	for (len = 0; len < LINUX_IFNAMSIZ; ++len)
260 		if (!isalpha(lxname[len]) || lxname[len] == '\0')
261 			break;
262 	if (len == 0 || len == LINUX_IFNAMSIZ)
263 		return (NULL);
264 	/* Linux loopback interface name is lo (not lo0) */
265 	is_lo = (len == 2 && strncmp(lxname, "lo", len) == 0);
266 	unit = (int)strtoul(lxname + len, &ep, 10);
267 	if ((ep == NULL || ep == lxname + len || ep >= lxname + LINUX_IFNAMSIZ) &&
268 	    is_lo == 0)
269 		return (NULL);
270 	index = 0;
271 	is_eth = (len == 3 && strncmp(lxname, "eth", len) == 0);
272 
273 	CURVNET_SET(TD_TO_VNET(td));
274 	IFNET_RLOCK();
275 	CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
276 		/*
277 		 * Allow Linux programs to use FreeBSD names. Don't presume
278 		 * we never have an interface named "eth", so don't make
279 		 * the test optional based on is_eth.
280 		 */
281 		if (strncmp(ifp->if_xname, lxname, LINUX_IFNAMSIZ) == 0)
282 			break;
283 		if (is_eth && IFP_IS_ETH(ifp) && unit == index++)
284 			break;
285 		if (is_lo && IFP_IS_LOOP(ifp))
286 			break;
287 	}
288 	IFNET_RUNLOCK();
289 	CURVNET_RESTORE();
290 	if (ifp != NULL && bsdname != NULL)
291 		strlcpy(bsdname, ifp->if_xname, IFNAMSIZ);
292 	return (ifp);
293 }
294 
295 void
296 linux_ifflags(struct ifnet *ifp, short *flags)
297 {
298 	unsigned short fl;
299 
300 	fl = (ifp->if_flags | ifp->if_drv_flags) & 0xffff;
301 	*flags = 0;
302 	if (fl & IFF_UP)
303 		*flags |= LINUX_IFF_UP;
304 	if (fl & IFF_BROADCAST)
305 		*flags |= LINUX_IFF_BROADCAST;
306 	if (fl & IFF_DEBUG)
307 		*flags |= LINUX_IFF_DEBUG;
308 	if (fl & IFF_LOOPBACK)
309 		*flags |= LINUX_IFF_LOOPBACK;
310 	if (fl & IFF_POINTOPOINT)
311 		*flags |= LINUX_IFF_POINTOPOINT;
312 	if (fl & IFF_DRV_RUNNING)
313 		*flags |= LINUX_IFF_RUNNING;
314 	if (fl & IFF_NOARP)
315 		*flags |= LINUX_IFF_NOARP;
316 	if (fl & IFF_PROMISC)
317 		*flags |= LINUX_IFF_PROMISC;
318 	if (fl & IFF_ALLMULTI)
319 		*flags |= LINUX_IFF_ALLMULTI;
320 	if (fl & IFF_MULTICAST)
321 		*flags |= LINUX_IFF_MULTICAST;
322 }
323 
324 int
325 linux_ifhwaddr(struct ifnet *ifp, struct l_sockaddr *lsa)
326 {
327 	struct ifaddr *ifa;
328 	struct sockaddr_dl *sdl;
329 
330 	if (IFP_IS_LOOP(ifp)) {
331 		bzero(lsa, sizeof(*lsa));
332 		lsa->sa_family = LINUX_ARPHRD_LOOPBACK;
333 		return (0);
334 	}
335 
336 	if (!IFP_IS_ETH(ifp))
337 		return (ENOENT);
338 
339 	CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
340 		sdl = (struct sockaddr_dl*)ifa->ifa_addr;
341 		if (sdl != NULL && (sdl->sdl_family == AF_LINK) &&
342 		    (sdl->sdl_type == IFT_ETHER)) {
343 			bzero(lsa, sizeof(*lsa));
344 			lsa->sa_family = LINUX_ARPHRD_ETHER;
345 			bcopy(LLADDR(sdl), lsa->sa_data, LINUX_IFHWADDRLEN);
346 			return (0);
347 		}
348 	}
349 
350 	return (ENOENT);
351 }
352 
353 int
354 linux_to_bsd_domain(int domain)
355 {
356 
357 	switch (domain) {
358 	case LINUX_AF_UNSPEC:
359 		return (AF_UNSPEC);
360 	case LINUX_AF_UNIX:
361 		return (AF_LOCAL);
362 	case LINUX_AF_INET:
363 		return (AF_INET);
364 	case LINUX_AF_INET6:
365 		return (AF_INET6);
366 	case LINUX_AF_AX25:
367 		return (AF_CCITT);
368 	case LINUX_AF_IPX:
369 		return (AF_IPX);
370 	case LINUX_AF_APPLETALK:
371 		return (AF_APPLETALK);
372 	case LINUX_AF_NETLINK:
373 		return (AF_NETLINK);
374 	}
375 	return (-1);
376 }
377 
378 int
379 bsd_to_linux_domain(int domain)
380 {
381 
382 	switch (domain) {
383 	case AF_UNSPEC:
384 		return (LINUX_AF_UNSPEC);
385 	case AF_LOCAL:
386 		return (LINUX_AF_UNIX);
387 	case AF_INET:
388 		return (LINUX_AF_INET);
389 	case AF_INET6:
390 		return (LINUX_AF_INET6);
391 	case AF_CCITT:
392 		return (LINUX_AF_AX25);
393 	case AF_IPX:
394 		return (LINUX_AF_IPX);
395 	case AF_APPLETALK:
396 		return (LINUX_AF_APPLETALK);
397 	case AF_NETLINK:
398 		return (LINUX_AF_NETLINK);
399 	}
400 	return (-1);
401 }
402 
403 /*
404  * Based on the fact that:
405  * 1. Native and Linux storage of struct sockaddr
406  * and struct sockaddr_in6 are equal.
407  * 2. On Linux sa_family is the first member of all struct sockaddr.
408  */
409 int
410 bsd_to_linux_sockaddr(const struct sockaddr *sa, struct l_sockaddr **lsa,
411     socklen_t len)
412 {
413 	struct l_sockaddr *kosa;
414 	int bdom;
415 
416 	*lsa = NULL;
417 	if (len < 2 || len > UCHAR_MAX)
418 		return (EINVAL);
419 	bdom = bsd_to_linux_domain(sa->sa_family);
420 	if (bdom == -1)
421 		return (EAFNOSUPPORT);
422 
423 	kosa = malloc(len, M_LINUX, M_WAITOK);
424 	bcopy(sa, kosa, len);
425 	kosa->sa_family = bdom;
426 	*lsa = kosa;
427 	return (0);
428 }
429 
430 int
431 linux_to_bsd_sockaddr(const struct l_sockaddr *osa, struct sockaddr **sap,
432     socklen_t *len)
433 {
434 	struct sockaddr *sa;
435 	struct l_sockaddr *kosa;
436 #ifdef INET6
437 	struct sockaddr_in6 *sin6;
438 	bool  oldv6size;
439 #endif
440 	char *name;
441 	int salen, bdom, error, hdrlen, namelen;
442 
443 	if (*len < 2 || *len > UCHAR_MAX)
444 		return (EINVAL);
445 
446 	salen = *len;
447 
448 #ifdef INET6
449 	oldv6size = false;
450 	/*
451 	 * Check for old (pre-RFC2553) sockaddr_in6. We may accept it
452 	 * if it's a v4-mapped address, so reserve the proper space
453 	 * for it.
454 	 */
455 	if (salen == sizeof(struct sockaddr_in6) - sizeof(uint32_t)) {
456 		salen += sizeof(uint32_t);
457 		oldv6size = true;
458 	}
459 #endif
460 
461 	kosa = malloc(salen, M_SONAME, M_WAITOK);
462 
463 	if ((error = copyin(osa, kosa, *len)))
464 		goto out;
465 
466 	bdom = linux_to_bsd_domain(kosa->sa_family);
467 	if (bdom == -1) {
468 		error = EAFNOSUPPORT;
469 		goto out;
470 	}
471 
472 #ifdef INET6
473 	/*
474 	 * Older Linux IPv6 code uses obsolete RFC2133 struct sockaddr_in6,
475 	 * which lacks the scope id compared with RFC2553 one. If we detect
476 	 * the situation, reject the address and write a message to system log.
477 	 *
478 	 * Still accept addresses for which the scope id is not used.
479 	 */
480 	if (oldv6size) {
481 		if (bdom == AF_INET6) {
482 			sin6 = (struct sockaddr_in6 *)kosa;
483 			if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr) ||
484 			    (!IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr) &&
485 			     !IN6_IS_ADDR_SITELOCAL(&sin6->sin6_addr) &&
486 			     !IN6_IS_ADDR_V4COMPAT(&sin6->sin6_addr) &&
487 			     !IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr) &&
488 			     !IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))) {
489 				sin6->sin6_scope_id = 0;
490 			} else {
491 				linux_msg(curthread,
492 				    "obsolete pre-RFC2553 sockaddr_in6 rejected");
493 				error = EINVAL;
494 				goto out;
495 			}
496 		} else
497 			salen -= sizeof(uint32_t);
498 	}
499 #endif
500 	if (bdom == AF_INET) {
501 		if (salen < sizeof(struct sockaddr_in)) {
502 			error = EINVAL;
503 			goto out;
504 		}
505 		salen = sizeof(struct sockaddr_in);
506 	}
507 
508 	if (bdom == AF_LOCAL && salen > sizeof(struct sockaddr_un)) {
509 		hdrlen = offsetof(struct sockaddr_un, sun_path);
510 		name = ((struct sockaddr_un *)kosa)->sun_path;
511 		if (*name == '\0') {
512 			/*
513 			 * Linux abstract namespace starts with a NULL byte.
514 			 * XXX We do not support abstract namespace yet.
515 			 */
516 			namelen = strnlen(name + 1, salen - hdrlen - 1) + 1;
517 		} else
518 			namelen = strnlen(name, salen - hdrlen);
519 		salen = hdrlen + namelen;
520 		if (salen > sizeof(struct sockaddr_un)) {
521 			error = ENAMETOOLONG;
522 			goto out;
523 		}
524 	}
525 
526 	if (bdom == AF_NETLINK) {
527 		if (salen < sizeof(struct sockaddr_nl)) {
528 			error = EINVAL;
529 			goto out;
530 		}
531 		salen = sizeof(struct sockaddr_nl);
532 	}
533 
534 	sa = (struct sockaddr *)kosa;
535 	sa->sa_family = bdom;
536 	sa->sa_len = salen;
537 
538 	*sap = sa;
539 	*len = salen;
540 	return (0);
541 
542 out:
543 	free(kosa, M_SONAME);
544 	return (error);
545 }
546 
547 void
548 linux_dev_shm_create(void)
549 {
550 	int error;
551 
552 	error = make_dev_p(MAKEDEV_CHECKNAME | MAKEDEV_WAITOK, &dev_shm_cdev,
553 	    &dev_shm_cdevsw, NULL, UID_ROOT, GID_WHEEL, 0, "shm/.mountpoint");
554 	if (error != 0) {
555 		printf("%s: failed to create device node, error %d\n",
556 		    __func__, error);
557 	}
558 }
559 
560 void
561 linux_dev_shm_destroy(void)
562 {
563 
564 	destroy_dev(dev_shm_cdev);
565 }
566 
567 int
568 bsd_to_linux_bits_(int value, struct bsd_to_linux_bitmap *bitmap,
569     size_t mapcnt, int no_value)
570 {
571 	int bsd_mask, bsd_value, linux_mask, linux_value;
572 	int linux_ret;
573 	size_t i;
574 	bool applied;
575 
576 	applied = false;
577 	linux_ret = 0;
578 	for (i = 0; i < mapcnt; ++i) {
579 		bsd_mask = bitmap[i].bsd_mask;
580 		bsd_value = bitmap[i].bsd_value;
581 		if (bsd_mask == 0)
582 			bsd_mask = bsd_value;
583 
584 		linux_mask = bitmap[i].linux_mask;
585 		linux_value = bitmap[i].linux_value;
586 		if (linux_mask == 0)
587 			linux_mask = linux_value;
588 
589 		/*
590 		 * If a mask larger than just the value is set, we explicitly
591 		 * want to make sure that only this bit we mapped within that
592 		 * mask is set.
593 		 */
594 		if ((value & bsd_mask) == bsd_value) {
595 			linux_ret = (linux_ret & ~linux_mask) | linux_value;
596 			applied = true;
597 		}
598 	}
599 
600 	if (!applied)
601 		return (no_value);
602 	return (linux_ret);
603 }
604 
605 int
606 linux_to_bsd_bits_(int value, struct bsd_to_linux_bitmap *bitmap,
607     size_t mapcnt, int no_value)
608 {
609 	int bsd_mask, bsd_value, linux_mask, linux_value;
610 	int bsd_ret;
611 	size_t i;
612 	bool applied;
613 
614 	applied = false;
615 	bsd_ret = 0;
616 	for (i = 0; i < mapcnt; ++i) {
617 		bsd_mask = bitmap[i].bsd_mask;
618 		bsd_value = bitmap[i].bsd_value;
619 		if (bsd_mask == 0)
620 			bsd_mask = bsd_value;
621 
622 		linux_mask = bitmap[i].linux_mask;
623 		linux_value = bitmap[i].linux_value;
624 		if (linux_mask == 0)
625 			linux_mask = linux_value;
626 
627 		/*
628 		 * If a mask larger than just the value is set, we explicitly
629 		 * want to make sure that only this bit we mapped within that
630 		 * mask is set.
631 		 */
632 		if ((value & linux_mask) == linux_value) {
633 			bsd_ret = (bsd_ret & ~bsd_mask) | bsd_value;
634 			applied = true;
635 		}
636 	}
637 
638 	if (!applied)
639 		return (no_value);
640 	return (bsd_ret);
641 }
642 
643 void
644 linux_to_bsd_poll_events(struct thread *td, int fd, short lev,
645     short *bev)
646 {
647 	struct file *fp;
648 	int error;
649 	short bits = 0;
650 
651 	if (lev & LINUX_POLLIN)
652 		bits |= POLLIN;
653 	if (lev & LINUX_POLLPRI)
654 		bits |=	POLLPRI;
655 	if (lev & LINUX_POLLOUT)
656 		bits |= POLLOUT;
657 	if (lev & LINUX_POLLERR)
658 		bits |= POLLERR;
659 	if (lev & LINUX_POLLHUP)
660 		bits |= POLLHUP;
661 	if (lev & LINUX_POLLNVAL)
662 		bits |= POLLNVAL;
663 	if (lev & LINUX_POLLRDNORM)
664 		bits |= POLLRDNORM;
665 	if (lev & LINUX_POLLRDBAND)
666 		bits |= POLLRDBAND;
667 	if (lev & LINUX_POLLWRBAND)
668 		bits |= POLLWRBAND;
669 	if (lev & LINUX_POLLWRNORM)
670 		bits |= POLLWRNORM;
671 
672 	if (lev & LINUX_POLLRDHUP) {
673 		/*
674 		 * It seems that the Linux silencly ignores POLLRDHUP
675 		 * on non-socket file descriptors unlike FreeBSD, where
676 		 * events bits is more strictly checked (POLLSTANDARD).
677 		 */
678 		error = fget_unlocked(td, fd, &cap_no_rights, &fp);
679 		if (error == 0) {
680 			/*
681 			 * XXX. On FreeBSD POLLRDHUP applies only to
682 			 * stream sockets.
683 			 */
684 			if (fp->f_type == DTYPE_SOCKET)
685 				bits |= POLLRDHUP;
686 			fdrop(fp, td);
687 		}
688 	}
689 
690 	if (lev & LINUX_POLLMSG)
691 		LINUX_RATELIMIT_MSG_OPT1("unsupported POLLMSG, events(%d)", lev);
692 	if (lev & LINUX_POLLREMOVE)
693 		LINUX_RATELIMIT_MSG_OPT1("unsupported POLLREMOVE, events(%d)", lev);
694 
695 	*bev = bits;
696 }
697 
698 void
699 bsd_to_linux_poll_events(short bev, short *lev)
700 {
701 	short bits = 0;
702 
703 	if (bev & POLLIN)
704 		bits |= LINUX_POLLIN;
705 	if (bev & POLLPRI)
706 		bits |=	LINUX_POLLPRI;
707 	if (bev & (POLLOUT | POLLWRNORM))
708 		/*
709 		 * POLLWRNORM is equal to POLLOUT on FreeBSD,
710 		 * but not on Linux
711 		 */
712 		bits |= LINUX_POLLOUT;
713 	if (bev & POLLERR)
714 		bits |= LINUX_POLLERR;
715 	if (bev & POLLHUP)
716 		bits |= LINUX_POLLHUP;
717 	if (bev & POLLNVAL)
718 		bits |= LINUX_POLLNVAL;
719 	if (bev & POLLRDNORM)
720 		bits |= LINUX_POLLRDNORM;
721 	if (bev & POLLRDBAND)
722 		bits |= LINUX_POLLRDBAND;
723 	if (bev & POLLWRBAND)
724 		bits |= LINUX_POLLWRBAND;
725 	if (bev & POLLRDHUP)
726 		bits |= LINUX_POLLRDHUP;
727 
728 	*lev = bits;
729 }
730 
731 bool
732 linux_use_real_ifname(const struct ifnet *ifp)
733 {
734 
735 	return (use_real_ifnames || !IFP_IS_ETH(ifp));
736 }
737