xref: /freebsd/sys/compat/linux/linux.c (revision 675aae732d3dd2ec0f12f39df3a1fbfe693a4ebd)
1 /*-
2  * Copyright (c) 2015 Dmitry Chagin
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <opt_inet6.h>
31 
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/conf.h>
35 #include <sys/ctype.h>
36 #include <sys/jail.h>
37 #include <sys/lock.h>
38 #include <sys/malloc.h>
39 #include <sys/signalvar.h>
40 #include <sys/socket.h>
41 #include <sys/socketvar.h>
42 
43 #include <net/if.h>
44 #include <net/if_var.h>
45 #include <net/if_dl.h>
46 #include <net/if_types.h>
47 
48 #include <sys/un.h>
49 #include <netinet/in.h>
50 
51 #include <compat/linux/linux.h>
52 #include <compat/linux/linux_common.h>
53 #include <compat/linux/linux_util.h>
54 
55 struct futex_list futex_list;
56 struct mtx futex_mtx;			/* protects the futex list */
57 
58 CTASSERT(LINUX_IFNAMSIZ == IFNAMSIZ);
59 
60 static int bsd_to_linux_sigtbl[LINUX_SIGTBLSZ] = {
61 	LINUX_SIGHUP,	/* SIGHUP */
62 	LINUX_SIGINT,	/* SIGINT */
63 	LINUX_SIGQUIT,	/* SIGQUIT */
64 	LINUX_SIGILL,	/* SIGILL */
65 	LINUX_SIGTRAP,	/* SIGTRAP */
66 	LINUX_SIGABRT,	/* SIGABRT */
67 	0,		/* SIGEMT */
68 	LINUX_SIGFPE,	/* SIGFPE */
69 	LINUX_SIGKILL,	/* SIGKILL */
70 	LINUX_SIGBUS,	/* SIGBUS */
71 	LINUX_SIGSEGV,	/* SIGSEGV */
72 	LINUX_SIGSYS,	/* SIGSYS */
73 	LINUX_SIGPIPE,	/* SIGPIPE */
74 	LINUX_SIGALRM,	/* SIGALRM */
75 	LINUX_SIGTERM,	/* SIGTERM */
76 	LINUX_SIGURG,	/* SIGURG */
77 	LINUX_SIGSTOP,	/* SIGSTOP */
78 	LINUX_SIGTSTP,	/* SIGTSTP */
79 	LINUX_SIGCONT,	/* SIGCONT */
80 	LINUX_SIGCHLD,	/* SIGCHLD */
81 	LINUX_SIGTTIN,	/* SIGTTIN */
82 	LINUX_SIGTTOU,	/* SIGTTOU */
83 	LINUX_SIGIO,	/* SIGIO */
84 	LINUX_SIGXCPU,	/* SIGXCPU */
85 	LINUX_SIGXFSZ,	/* SIGXFSZ */
86 	LINUX_SIGVTALRM,/* SIGVTALRM */
87 	LINUX_SIGPROF,	/* SIGPROF */
88 	LINUX_SIGWINCH,	/* SIGWINCH */
89 	0,		/* SIGINFO */
90 	LINUX_SIGUSR1,	/* SIGUSR1 */
91 	LINUX_SIGUSR2	/* SIGUSR2 */
92 };
93 
94 static int linux_to_bsd_sigtbl[LINUX_SIGTBLSZ] = {
95 	SIGHUP,		/* LINUX_SIGHUP */
96 	SIGINT,		/* LINUX_SIGINT */
97 	SIGQUIT,	/* LINUX_SIGQUIT */
98 	SIGILL,		/* LINUX_SIGILL */
99 	SIGTRAP,	/* LINUX_SIGTRAP */
100 	SIGABRT,	/* LINUX_SIGABRT */
101 	SIGBUS,		/* LINUX_SIGBUS */
102 	SIGFPE,		/* LINUX_SIGFPE */
103 	SIGKILL,	/* LINUX_SIGKILL */
104 	SIGUSR1,	/* LINUX_SIGUSR1 */
105 	SIGSEGV,	/* LINUX_SIGSEGV */
106 	SIGUSR2,	/* LINUX_SIGUSR2 */
107 	SIGPIPE,	/* LINUX_SIGPIPE */
108 	SIGALRM,	/* LINUX_SIGALRM */
109 	SIGTERM,	/* LINUX_SIGTERM */
110 	SIGBUS,		/* LINUX_SIGSTKFLT */
111 	SIGCHLD,	/* LINUX_SIGCHLD */
112 	SIGCONT,	/* LINUX_SIGCONT */
113 	SIGSTOP,	/* LINUX_SIGSTOP */
114 	SIGTSTP,	/* LINUX_SIGTSTP */
115 	SIGTTIN,	/* LINUX_SIGTTIN */
116 	SIGTTOU,	/* LINUX_SIGTTOU */
117 	SIGURG,		/* LINUX_SIGURG */
118 	SIGXCPU,	/* LINUX_SIGXCPU */
119 	SIGXFSZ,	/* LINUX_SIGXFSZ */
120 	SIGVTALRM,	/* LINUX_SIGVTALARM */
121 	SIGPROF,	/* LINUX_SIGPROF */
122 	SIGWINCH,	/* LINUX_SIGWINCH */
123 	SIGIO,		/* LINUX_SIGIO */
124 	/*
125 	 * FreeBSD does not have SIGPWR signal, map Linux SIGPWR signal
126 	 * to the first unused FreeBSD signal number. Since Linux supports
127 	 * signals from 1 to 64 we are ok here as our SIGRTMIN = 65.
128 	 */
129 	SIGRTMIN,	/* LINUX_SIGPWR */
130 	SIGSYS		/* LINUX_SIGSYS */
131 };
132 
133 static struct cdev *dev_shm_cdev;
134 static struct cdevsw dev_shm_cdevsw = {
135      .d_version = D_VERSION,
136      .d_name    = "dev_shm",
137 };
138 
139 /*
140  * Map Linux RT signals to the FreeBSD RT signals.
141  */
142 static inline int
143 linux_to_bsd_rt_signal(int sig)
144 {
145 
146 	return (SIGRTMIN + 1 + sig - LINUX_SIGRTMIN);
147 }
148 
149 static inline int
150 bsd_to_linux_rt_signal(int sig)
151 {
152 
153 	return (sig - SIGRTMIN - 1 + LINUX_SIGRTMIN);
154 }
155 
156 int
157 linux_to_bsd_signal(int sig)
158 {
159 
160 	KASSERT(sig > 0 && sig <= LINUX_SIGRTMAX, ("invalid Linux signal %d\n", sig));
161 
162 	if (sig < LINUX_SIGRTMIN)
163 		return (linux_to_bsd_sigtbl[_SIG_IDX(sig)]);
164 
165 	return (linux_to_bsd_rt_signal(sig));
166 }
167 
168 int
169 bsd_to_linux_signal(int sig)
170 {
171 
172 	if (sig <= LINUX_SIGTBLSZ)
173 		return (bsd_to_linux_sigtbl[_SIG_IDX(sig)]);
174 	if (sig == SIGRTMIN)
175 		return (LINUX_SIGPWR);
176 
177 	return (bsd_to_linux_rt_signal(sig));
178 }
179 
180 int
181 linux_to_bsd_sigaltstack(int lsa)
182 {
183 	int bsa = 0;
184 
185 	if (lsa & LINUX_SS_DISABLE)
186 		bsa |= SS_DISABLE;
187 	/*
188 	 * Linux ignores SS_ONSTACK flag for ss
189 	 * parameter while FreeBSD prohibits it.
190 	 */
191 	return (bsa);
192 }
193 
194 int
195 bsd_to_linux_sigaltstack(int bsa)
196 {
197 	int lsa = 0;
198 
199 	if (bsa & SS_DISABLE)
200 		lsa |= LINUX_SS_DISABLE;
201 	if (bsa & SS_ONSTACK)
202 		lsa |= LINUX_SS_ONSTACK;
203 	return (lsa);
204 }
205 
206 void
207 linux_to_bsd_sigset(l_sigset_t *lss, sigset_t *bss)
208 {
209 	int b, l;
210 
211 	SIGEMPTYSET(*bss);
212 	for (l = 1; l <= LINUX_SIGRTMAX; l++) {
213 		if (LINUX_SIGISMEMBER(*lss, l)) {
214 			b = linux_to_bsd_signal(l);
215 			if (b)
216 				SIGADDSET(*bss, b);
217 		}
218 	}
219 }
220 
221 void
222 bsd_to_linux_sigset(sigset_t *bss, l_sigset_t *lss)
223 {
224 	int b, l;
225 
226 	LINUX_SIGEMPTYSET(*lss);
227 	for (b = 1; b <= SIGRTMAX; b++) {
228 		if (SIGISMEMBER(*bss, b)) {
229 			l = bsd_to_linux_signal(b);
230 			if (l)
231 				LINUX_SIGADDSET(*lss, l);
232 		}
233 	}
234 }
235 
236 /*
237  * Translate a Linux interface name to a FreeBSD interface name,
238  * and return the associated ifnet structure
239  * bsdname and lxname need to be least IFNAMSIZ bytes long, but
240  * can point to the same buffer.
241  */
242 struct ifnet *
243 ifname_linux_to_bsd(struct thread *td, const char *lxname, char *bsdname)
244 {
245 	struct ifnet *ifp;
246 	int len, unit;
247 	char *ep;
248 	int index;
249 	bool is_eth, is_lo;
250 
251 	for (len = 0; len < LINUX_IFNAMSIZ; ++len)
252 		if (!isalpha(lxname[len]) || lxname[len] == '\0')
253 			break;
254 	if (len == 0 || len == LINUX_IFNAMSIZ)
255 		return (NULL);
256 	/* Linux loopback interface name is lo (not lo0) */
257 	is_lo = (len == 2 && strncmp(lxname, "lo", len) == 0);
258 	unit = (int)strtoul(lxname + len, &ep, 10);
259 	if ((ep == NULL || ep == lxname + len || ep >= lxname + LINUX_IFNAMSIZ) &&
260 	    is_lo == 0)
261 		return (NULL);
262 	index = 0;
263 	is_eth = (len == 3 && strncmp(lxname, "eth", len) == 0);
264 
265 	CURVNET_SET(TD_TO_VNET(td));
266 	IFNET_RLOCK();
267 	CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
268 		/*
269 		 * Allow Linux programs to use FreeBSD names. Don't presume
270 		 * we never have an interface named "eth", so don't make
271 		 * the test optional based on is_eth.
272 		 */
273 		if (strncmp(ifp->if_xname, lxname, LINUX_IFNAMSIZ) == 0)
274 			break;
275 		if (is_eth && IFP_IS_ETH(ifp) && unit == index++)
276 			break;
277 		if (is_lo && IFP_IS_LOOP(ifp))
278 			break;
279 	}
280 	IFNET_RUNLOCK();
281 	CURVNET_RESTORE();
282 	if (ifp != NULL && bsdname != NULL)
283 		strlcpy(bsdname, ifp->if_xname, IFNAMSIZ);
284 	return (ifp);
285 }
286 
287 void
288 linux_ifflags(struct ifnet *ifp, short *flags)
289 {
290 	unsigned short fl;
291 
292 	fl = (ifp->if_flags | ifp->if_drv_flags) & 0xffff;
293 	*flags = 0;
294 	if (fl & IFF_UP)
295 		*flags |= LINUX_IFF_UP;
296 	if (fl & IFF_BROADCAST)
297 		*flags |= LINUX_IFF_BROADCAST;
298 	if (fl & IFF_DEBUG)
299 		*flags |= LINUX_IFF_DEBUG;
300 	if (fl & IFF_LOOPBACK)
301 		*flags |= LINUX_IFF_LOOPBACK;
302 	if (fl & IFF_POINTOPOINT)
303 		*flags |= LINUX_IFF_POINTOPOINT;
304 	if (fl & IFF_DRV_RUNNING)
305 		*flags |= LINUX_IFF_RUNNING;
306 	if (fl & IFF_NOARP)
307 		*flags |= LINUX_IFF_NOARP;
308 	if (fl & IFF_PROMISC)
309 		*flags |= LINUX_IFF_PROMISC;
310 	if (fl & IFF_ALLMULTI)
311 		*flags |= LINUX_IFF_ALLMULTI;
312 	if (fl & IFF_MULTICAST)
313 		*flags |= LINUX_IFF_MULTICAST;
314 }
315 
316 int
317 linux_ifhwaddr(struct ifnet *ifp, struct l_sockaddr *lsa)
318 {
319 	struct ifaddr *ifa;
320 	struct sockaddr_dl *sdl;
321 
322 	if (IFP_IS_LOOP(ifp)) {
323 		bzero(lsa, sizeof(*lsa));
324 		lsa->sa_family = LINUX_ARPHRD_LOOPBACK;
325 		return (0);
326 	}
327 
328 	if (!IFP_IS_ETH(ifp))
329 		return (ENOENT);
330 
331 	CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
332 		sdl = (struct sockaddr_dl*)ifa->ifa_addr;
333 		if (sdl != NULL && (sdl->sdl_family == AF_LINK) &&
334 		    (sdl->sdl_type == IFT_ETHER)) {
335 			bzero(lsa, sizeof(*lsa));
336 			lsa->sa_family = LINUX_ARPHRD_ETHER;
337 			bcopy(LLADDR(sdl), lsa->sa_data, LINUX_IFHWADDRLEN);
338 			return (0);
339 		}
340 	}
341 
342 	return (ENOENT);
343 }
344 
345 int
346 linux_to_bsd_domain(int domain)
347 {
348 
349 	switch (domain) {
350 	case LINUX_AF_UNSPEC:
351 		return (AF_UNSPEC);
352 	case LINUX_AF_UNIX:
353 		return (AF_LOCAL);
354 	case LINUX_AF_INET:
355 		return (AF_INET);
356 	case LINUX_AF_INET6:
357 		return (AF_INET6);
358 	case LINUX_AF_AX25:
359 		return (AF_CCITT);
360 	case LINUX_AF_IPX:
361 		return (AF_IPX);
362 	case LINUX_AF_APPLETALK:
363 		return (AF_APPLETALK);
364 	}
365 	return (-1);
366 }
367 
368 int
369 bsd_to_linux_domain(int domain)
370 {
371 
372 	switch (domain) {
373 	case AF_UNSPEC:
374 		return (LINUX_AF_UNSPEC);
375 	case AF_LOCAL:
376 		return (LINUX_AF_UNIX);
377 	case AF_INET:
378 		return (LINUX_AF_INET);
379 	case AF_INET6:
380 		return (LINUX_AF_INET6);
381 	case AF_CCITT:
382 		return (LINUX_AF_AX25);
383 	case AF_IPX:
384 		return (LINUX_AF_IPX);
385 	case AF_APPLETALK:
386 		return (LINUX_AF_APPLETALK);
387 	}
388 	return (-1);
389 }
390 
391 /*
392  * Based on the fact that:
393  * 1. Native and Linux storage of struct sockaddr
394  * and struct sockaddr_in6 are equal.
395  * 2. On Linux sa_family is the first member of all struct sockaddr.
396  */
397 int
398 bsd_to_linux_sockaddr(const struct sockaddr *sa, struct l_sockaddr **lsa,
399     socklen_t len)
400 {
401 	struct l_sockaddr *kosa;
402 	int error, bdom;
403 
404 	*lsa = NULL;
405 	if (len < 2 || len > UCHAR_MAX)
406 		return (EINVAL);
407 
408 	kosa = malloc(len, M_SONAME, M_WAITOK);
409 	bcopy(sa, kosa, len);
410 
411 	bdom = bsd_to_linux_domain(sa->sa_family);
412 	if (bdom == -1) {
413 		error = EAFNOSUPPORT;
414 		goto out;
415 	}
416 
417 	kosa->sa_family = bdom;
418 	*lsa = kosa;
419 	return (0);
420 
421 out:
422 	free(kosa, M_SONAME);
423 	return (error);
424 }
425 
426 int
427 linux_to_bsd_sockaddr(const struct l_sockaddr *osa, struct sockaddr **sap,
428     socklen_t *len)
429 {
430 	struct sockaddr *sa;
431 	struct l_sockaddr *kosa;
432 #ifdef INET6
433 	struct sockaddr_in6 *sin6;
434 	bool  oldv6size;
435 #endif
436 	char *name;
437 	int salen, bdom, error, hdrlen, namelen;
438 
439 	if (*len < 2 || *len > UCHAR_MAX)
440 		return (EINVAL);
441 
442 	salen = *len;
443 
444 #ifdef INET6
445 	oldv6size = false;
446 	/*
447 	 * Check for old (pre-RFC2553) sockaddr_in6. We may accept it
448 	 * if it's a v4-mapped address, so reserve the proper space
449 	 * for it.
450 	 */
451 	if (salen == sizeof(struct sockaddr_in6) - sizeof(uint32_t)) {
452 		salen += sizeof(uint32_t);
453 		oldv6size = true;
454 	}
455 #endif
456 
457 	kosa = malloc(salen, M_SONAME, M_WAITOK);
458 
459 	if ((error = copyin(osa, kosa, *len)))
460 		goto out;
461 
462 	bdom = linux_to_bsd_domain(kosa->sa_family);
463 	if (bdom == -1) {
464 		error = EAFNOSUPPORT;
465 		goto out;
466 	}
467 
468 #ifdef INET6
469 	/*
470 	 * Older Linux IPv6 code uses obsolete RFC2133 struct sockaddr_in6,
471 	 * which lacks the scope id compared with RFC2553 one. If we detect
472 	 * the situation, reject the address and write a message to system log.
473 	 *
474 	 * Still accept addresses for which the scope id is not used.
475 	 */
476 	if (oldv6size) {
477 		if (bdom == AF_INET6) {
478 			sin6 = (struct sockaddr_in6 *)kosa;
479 			if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr) ||
480 			    (!IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr) &&
481 			     !IN6_IS_ADDR_SITELOCAL(&sin6->sin6_addr) &&
482 			     !IN6_IS_ADDR_V4COMPAT(&sin6->sin6_addr) &&
483 			     !IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr) &&
484 			     !IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))) {
485 				sin6->sin6_scope_id = 0;
486 			} else {
487 				linux_msg(curthread,
488 				    "obsolete pre-RFC2553 sockaddr_in6 rejected");
489 				error = EINVAL;
490 				goto out;
491 			}
492 		} else
493 			salen -= sizeof(uint32_t);
494 	}
495 #endif
496 	if (bdom == AF_INET) {
497 		if (salen < sizeof(struct sockaddr_in)) {
498 			error = EINVAL;
499 			goto out;
500 		}
501 		salen = sizeof(struct sockaddr_in);
502 	}
503 
504 	if (bdom == AF_LOCAL && salen > sizeof(struct sockaddr_un)) {
505 		hdrlen = offsetof(struct sockaddr_un, sun_path);
506 		name = ((struct sockaddr_un *)kosa)->sun_path;
507 		if (*name == '\0') {
508 			/*
509 			 * Linux abstract namespace starts with a NULL byte.
510 			 * XXX We do not support abstract namespace yet.
511 			 */
512 			namelen = strnlen(name + 1, salen - hdrlen - 1) + 1;
513 		} else
514 			namelen = strnlen(name, salen - hdrlen);
515 		salen = hdrlen + namelen;
516 		if (salen > sizeof(struct sockaddr_un)) {
517 			error = ENAMETOOLONG;
518 			goto out;
519 		}
520 	}
521 
522 	sa = (struct sockaddr *)kosa;
523 	sa->sa_family = bdom;
524 	sa->sa_len = salen;
525 
526 	*sap = sa;
527 	*len = salen;
528 	return (0);
529 
530 out:
531 	free(kosa, M_SONAME);
532 	return (error);
533 }
534 
535 void
536 linux_dev_shm_create(void)
537 {
538 	int error;
539 
540 	error = make_dev_p(MAKEDEV_CHECKNAME | MAKEDEV_WAITOK, &dev_shm_cdev,
541 	    &dev_shm_cdevsw, NULL, UID_ROOT, GID_WHEEL, 0, "shm/.mountpoint");
542 	if (error != 0) {
543 		printf("%s: failed to create device node, error %d\n",
544 		    __func__, error);
545 	}
546 }
547 
548 void
549 linux_dev_shm_destroy(void)
550 {
551 
552 	destroy_dev(dev_shm_cdev);
553 }
554 
555 int
556 bsd_to_linux_bits_(int value, struct bsd_to_linux_bitmap *bitmap,
557     size_t mapcnt, int no_value)
558 {
559 	int bsd_mask, bsd_value, linux_mask, linux_value;
560 	int linux_ret;
561 	size_t i;
562 	bool applied;
563 
564 	applied = false;
565 	linux_ret = 0;
566 	for (i = 0; i < mapcnt; ++i) {
567 		bsd_mask = bitmap[i].bsd_mask;
568 		bsd_value = bitmap[i].bsd_value;
569 		if (bsd_mask == 0)
570 			bsd_mask = bsd_value;
571 
572 		linux_mask = bitmap[i].linux_mask;
573 		linux_value = bitmap[i].linux_value;
574 		if (linux_mask == 0)
575 			linux_mask = linux_value;
576 
577 		/*
578 		 * If a mask larger than just the value is set, we explicitly
579 		 * want to make sure that only this bit we mapped within that
580 		 * mask is set.
581 		 */
582 		if ((value & bsd_mask) == bsd_value) {
583 			linux_ret = (linux_ret & ~linux_mask) | linux_value;
584 			applied = true;
585 		}
586 	}
587 
588 	if (!applied)
589 		return (no_value);
590 	return (linux_ret);
591 }
592 
593 int
594 linux_to_bsd_bits_(int value, struct bsd_to_linux_bitmap *bitmap,
595     size_t mapcnt, int no_value)
596 {
597 	int bsd_mask, bsd_value, linux_mask, linux_value;
598 	int bsd_ret;
599 	size_t i;
600 	bool applied;
601 
602 	applied = false;
603 	bsd_ret = 0;
604 	for (i = 0; i < mapcnt; ++i) {
605 		bsd_mask = bitmap[i].bsd_mask;
606 		bsd_value = bitmap[i].bsd_value;
607 		if (bsd_mask == 0)
608 			bsd_mask = bsd_value;
609 
610 		linux_mask = bitmap[i].linux_mask;
611 		linux_value = bitmap[i].linux_value;
612 		if (linux_mask == 0)
613 			linux_mask = linux_value;
614 
615 		/*
616 		 * If a mask larger than just the value is set, we explicitly
617 		 * want to make sure that only this bit we mapped within that
618 		 * mask is set.
619 		 */
620 		if ((value & linux_mask) == linux_value) {
621 			bsd_ret = (bsd_ret & ~bsd_mask) | bsd_value;
622 			applied = true;
623 		}
624 	}
625 
626 	if (!applied)
627 		return (no_value);
628 	return (bsd_ret);
629 }
630