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linux_signal.c revision 1.31.2.7
      1 /*	$NetBSD: linux_signal.c,v 1.31.2.7 2002/07/12 01:40:02 nathanw Exp $	*/
      2 /*-
      3  * Copyright (c) 1995, 1998 The NetBSD Foundation, Inc.
      4  * All rights reserved.
      5  *
      6  * This code is derived from software contributed to The NetBSD Foundation
      7  * by Frank van der Linden and Eric Haszlakiewicz.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  * 3. All advertising materials mentioning features or use of this software
     18  *    must display the following acknowledgement:
     19  *	This product includes software developed by the NetBSD
     20  *	Foundation, Inc. and its contributors.
     21  * 4. Neither the name of The NetBSD Foundation nor the names of its
     22  *    contributors may be used to endorse or promote products derived
     23  *    from this software without specific prior written permission.
     24  *
     25  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     26  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     35  * POSSIBILITY OF SUCH DAMAGE.
     36  */
     37 /*
     38  * heavily from: svr4_signal.c,v 1.7 1995/01/09 01:04:21 christos Exp
     39  */
     40 
     41 /*
     42  *   Functions in multiarch:
     43  *	linux_sys_signal	: linux_sig_notalpha.c
     44  *	linux_sys_siggetmask	: linux_sig_notalpha.c
     45  *	linux_sys_sigsetmask	: linux_sig_notalpha.c
     46  *	linux_sys_pause		: linux_sig_notalpha.c
     47  *	linux_sys_sigaction	: linux_sigaction.c
     48  *
     49  */
     50 
     51 /*
     52  *   Unimplemented:
     53  *	linux_sys_rt_sigtimedwait	: sigsuspend w/timeout.
     54  */
     55 
     56 #include <sys/cdefs.h>
     57 __KERNEL_RCSID(0, "$NetBSD: linux_signal.c,v 1.31.2.7 2002/07/12 01:40:02 nathanw Exp $");
     58 
     59 #define COMPAT_LINUX 1
     60 
     61 #include <sys/param.h>
     62 #include <sys/systm.h>
     63 #include <sys/namei.h>
     64 #include <sys/proc.h>
     65 #include <sys/filedesc.h>
     66 #include <sys/ioctl.h>
     67 #include <sys/mount.h>
     68 #include <sys/kernel.h>
     69 #include <sys/signal.h>
     70 #include <sys/signalvar.h>
     71 #include <sys/malloc.h>
     72 
     73 #include <sys/sa.h>
     74 #include <sys/syscallargs.h>
     75 
     76 #include <compat/linux/common/linux_types.h>
     77 #include <compat/linux/common/linux_signal.h>
     78 #include <compat/linux/common/linux_siginfo.h>
     79 #include <compat/linux/common/linux_util.h>
     80 
     81 #include <compat/linux/linux_syscallargs.h>
     82 
     83 /* Locally used defines (in bsd<->linux conversion functions): */
     84 #define	linux_sigemptyset(s)	memset((s), 0, sizeof(*(s)))
     85 #define	linux_sigismember(s, n)	((s)->sig[((n) - 1) / LINUX__NSIG_BPW]	\
     86 					& (1 << ((n) - 1) % LINUX__NSIG_BPW))
     87 #define	linux_sigaddset(s, n)	((s)->sig[((n) - 1) / LINUX__NSIG_BPW]	\
     88 					|= (1 << ((n) - 1) % LINUX__NSIG_BPW))
     89 
     90 #ifdef DEBUG_LINUX
     91 #define DPRINTF(a)	uprintf a
     92 #else
     93 #define DPRINTF(a)
     94 #endif
     95 
     96 extern const int native_to_linux_signo[];
     97 extern const int linux_to_native_signo[];
     98 
     99 /*
    100  * Convert between Linux and BSD signal sets.
    101  */
    102 #if LINUX__NSIG_WORDS > 1
    103 void
    104 linux_old_extra_to_native_sigset(bss, lss, extra)
    105 	sigset_t *bss;
    106 	const linux_old_sigset_t *lss;
    107 	const unsigned long *extra;
    108 {
    109 	linux_sigset_t lsnew;
    110 
    111 	/* convert old sigset to new sigset */
    112 	linux_sigemptyset(&lsnew);
    113 	lsnew.sig[0] = *lss;
    114 	if (extra)
    115 		memcpy(&lsnew.sig[1], extra,
    116 		    sizeof(linux_sigset_t) - sizeof(linux_old_sigset_t));
    117 
    118 	linux_to_native_sigset(bss, &lsnew);
    119 }
    120 
    121 void
    122 native_to_linux_old_extra_sigset(lss, extra, bss)
    123 	linux_old_sigset_t *lss;
    124 	unsigned long *extra;
    125 	const sigset_t *bss;
    126 {
    127 	linux_sigset_t lsnew;
    128 
    129 	native_to_linux_sigset(&lsnew, bss);
    130 
    131 	/* convert new sigset to old sigset */
    132 	*lss = lsnew.sig[0];
    133 	if (extra)
    134 		memcpy(extra, &lsnew.sig[1],
    135 		    sizeof(linux_sigset_t) - sizeof(linux_old_sigset_t));
    136 }
    137 #endif
    138 
    139 void
    140 linux_to_native_sigset(bss, lss)
    141 	sigset_t *bss;
    142 	const linux_sigset_t *lss;
    143 {
    144 	int i, newsig;
    145 
    146 	sigemptyset(bss);
    147 	for (i = 1; i < LINUX__NSIG; i++) {
    148 		if (linux_sigismember(lss, i)) {
    149 			newsig = linux_to_native_signo[i];
    150 			if (newsig)
    151 				sigaddset(bss, newsig);
    152 		}
    153 	}
    154 }
    155 
    156 void
    157 native_to_linux_sigset(lss, bss)
    158 	linux_sigset_t *lss;
    159 	const sigset_t *bss;
    160 {
    161 	int i, newsig;
    162 
    163 	linux_sigemptyset(lss);
    164 	for (i = 1; i < NSIG; i++) {
    165 		if (sigismember(bss, i)) {
    166 			newsig = native_to_linux_signo[i];
    167 			if (newsig)
    168 				linux_sigaddset(lss, newsig);
    169 		}
    170 	}
    171 }
    172 
    173 unsigned int
    174 native_to_linux_sigflags(bsf)
    175 	const int bsf;
    176 {
    177 	unsigned int lsf = 0;
    178 	if ((bsf & SA_NOCLDSTOP) != 0)
    179 		lsf |= LINUX_SA_NOCLDSTOP;
    180 	if ((bsf & SA_NOCLDWAIT) != 0)
    181 		lsf |= LINUX_SA_NOCLDWAIT;
    182 	if ((bsf & SA_ONSTACK) != 0)
    183 		lsf |= LINUX_SA_ONSTACK;
    184 	if ((bsf & SA_RESTART) != 0)
    185 		lsf |= LINUX_SA_RESTART;
    186 	if ((bsf & SA_NODEFER) != 0)
    187 		lsf |= LINUX_SA_NOMASK;
    188 	if ((bsf & SA_RESETHAND) != 0)
    189 		lsf |= LINUX_SA_ONESHOT;
    190 	if ((bsf & SA_SIGINFO) != 0)
    191 		lsf |= LINUX_SA_SIGINFO;
    192 	return lsf;
    193 }
    194 
    195 int
    196 linux_to_native_sigflags(lsf)
    197 	const unsigned long lsf;
    198 {
    199 	int bsf = 0;
    200 	if ((lsf & LINUX_SA_NOCLDSTOP) != 0)
    201 		bsf |= SA_NOCLDSTOP;
    202 	if ((lsf & LINUX_SA_NOCLDWAIT) != 0)
    203 		bsf |= SA_NOCLDWAIT;
    204 	if ((lsf & LINUX_SA_ONSTACK) != 0)
    205 		bsf |= SA_ONSTACK;
    206 	if ((lsf & LINUX_SA_RESTART) != 0)
    207 		bsf |= SA_RESTART;
    208 	if ((lsf & LINUX_SA_ONESHOT) != 0)
    209 		bsf |= SA_RESETHAND;
    210 	if ((lsf & LINUX_SA_NOMASK) != 0)
    211 		bsf |= SA_NODEFER;
    212 	if ((lsf & LINUX_SA_SIGINFO) != 0)
    213 		bsf |= SA_SIGINFO;
    214 	if ((lsf & ~LINUX_SA_ALLBITS) != 0)
    215 		DPRINTF(("linux_old_to_native_sigflags: "
    216 		    "%lx extra bits ignored\n", lsf));
    217 	return bsf;
    218 }
    219 
    220 /*
    221  * Convert between Linux and BSD sigaction structures. Linux sometimes
    222  * has one extra field (sa_restorer) which we don't support.
    223  */
    224 void
    225 linux_old_to_native_sigaction(bsa, lsa)
    226 	struct sigaction *bsa;
    227 	const struct linux_old_sigaction *lsa;
    228 {
    229 	bsa->sa_handler = lsa->sa_handler;
    230 	linux_old_to_native_sigset(&bsa->sa_mask, &lsa->sa_mask);
    231 	bsa->sa_flags = linux_to_native_sigflags(lsa->sa_flags);
    232 #ifndef __alpha__
    233 /*
    234  * XXX: On the alpha sa_restorer is elsewhere.
    235  */
    236 	if (lsa->sa_restorer != NULL)
    237 		DPRINTF(("linux_old_to_native_sigaction: "
    238 		    "sa_restorer ignored\n"));
    239 #endif
    240 }
    241 
    242 void
    243 native_to_linux_old_sigaction(lsa, bsa)
    244 	struct linux_old_sigaction *lsa;
    245 	const struct sigaction *bsa;
    246 {
    247 	lsa->sa_handler = bsa->sa_handler;
    248 	native_to_linux_old_sigset(&lsa->sa_mask, &bsa->sa_mask);
    249 	lsa->sa_flags = native_to_linux_sigflags(bsa->sa_flags);
    250 #ifndef __alpha__
    251 	lsa->sa_restorer = NULL;
    252 #endif
    253 }
    254 
    255 /* ...and the new sigaction conversion funcs. */
    256 void
    257 linux_to_native_sigaction(bsa, lsa)
    258 	struct sigaction *bsa;
    259 	const struct linux_sigaction *lsa;
    260 {
    261 	bsa->sa_handler = lsa->sa_handler;
    262 	linux_to_native_sigset(&bsa->sa_mask, &lsa->sa_mask);
    263 	bsa->sa_flags = linux_to_native_sigflags(lsa->sa_flags);
    264 #ifndef __alpha__
    265 	if (lsa->sa_restorer != 0)
    266 		DPRINTF(("linux_to_native_sigaction: sa_restorer ignored\n"));
    267 #endif
    268 }
    269 
    270 void
    271 native_to_linux_sigaction(lsa, bsa)
    272 	struct linux_sigaction *lsa;
    273 	const struct sigaction *bsa;
    274 {
    275 	lsa->sa_handler = bsa->sa_handler;
    276 	native_to_linux_sigset(&lsa->sa_mask, &bsa->sa_mask);
    277 	lsa->sa_flags = native_to_linux_sigflags(bsa->sa_flags);
    278 #ifndef __alpha__
    279 	lsa->sa_restorer = NULL;
    280 #endif
    281 }
    282 
    283 /* ----------------------------------------------------------------------- */
    284 
    285 /*
    286  * The Linux sigaction() system call. Do the usual conversions,
    287  * and just call sigaction(). Some flags and values are silently
    288  * ignored (see above).
    289  */
    290 int
    291 linux_sys_rt_sigaction(l, v, retval)
    292 	struct lwp *l;
    293 	void *v;
    294 	register_t *retval;
    295 {
    296 	struct linux_sys_rt_sigaction_args /* {
    297 		syscallarg(int) signum;
    298 		syscallarg(const struct linux_sigaction *) nsa;
    299 		syscallarg(struct linux_sigaction *) osa;
    300 		syscallarg(size_t) sigsetsize;
    301 	} */ *uap = v;
    302 	struct proc *p = l->l_proc;
    303 	struct linux_sigaction nlsa, olsa;
    304 	struct sigaction nbsa, obsa;
    305 	int error, sig;
    306 
    307 	if (SCARG(uap, sigsetsize) != sizeof(linux_sigset_t))
    308 		return (EINVAL);
    309 
    310 	if (SCARG(uap, nsa)) {
    311 		error = copyin(SCARG(uap, nsa), &nlsa, sizeof(nlsa));
    312 		if (error)
    313 			return (error);
    314 		linux_to_native_sigaction(&nbsa, &nlsa);
    315 	}
    316 	sig = SCARG(uap, signum);
    317 	if (sig < 0 || sig >= LINUX__NSIG)
    318 		return (EINVAL);
    319 	if (sig > 0 && !linux_to_native_signo[sig]) {
    320 		/* Pretend that we did something useful for unknown signals. */
    321 		obsa.sa_handler = SIG_IGN;
    322 		sigemptyset(&obsa.sa_mask);
    323 		obsa.sa_flags = 0;
    324 	} else {
    325 		error = sigaction1(p, linux_to_native_signo[sig],
    326 		    SCARG(uap, nsa) ? &nbsa : NULL, SCARG(uap, osa) ? &obsa : NULL);
    327 		if (error)
    328 			return (error);
    329 	}
    330 	if (SCARG(uap, osa)) {
    331 		native_to_linux_sigaction(&olsa, &obsa);
    332 		error = copyout(&olsa, SCARG(uap, osa), sizeof(olsa));
    333 		if (error)
    334 			return (error);
    335 	}
    336 	return (0);
    337 }
    338 
    339 int
    340 linux_sigprocmask1(p, how, set, oset)
    341 	struct proc *p;
    342 	int how;
    343 	const linux_old_sigset_t *set;
    344 	linux_old_sigset_t *oset;
    345 {
    346 	linux_old_sigset_t nlss, olss;
    347 	sigset_t nbss, obss;
    348 	int error;
    349 
    350 	switch (how) {
    351 	case LINUX_SIG_BLOCK:
    352 		how = SIG_BLOCK;
    353 		break;
    354 	case LINUX_SIG_UNBLOCK:
    355 		how = SIG_UNBLOCK;
    356 		break;
    357 	case LINUX_SIG_SETMASK:
    358 		how = SIG_SETMASK;
    359 		break;
    360 	default:
    361 		return (EINVAL);
    362 	}
    363 
    364 	if (set) {
    365 		error = copyin(set, &nlss, sizeof(nlss));
    366 		if (error)
    367 			return (error);
    368 		linux_old_to_native_sigset(&nbss, &nlss);
    369 	}
    370 	error = sigprocmask1(p, how,
    371 	    set ? &nbss : NULL, oset ? &obss : NULL);
    372 	if (error)
    373 		return (error);
    374 	if (oset) {
    375 		native_to_linux_old_sigset(&olss, &obss);
    376 		error = copyout(&olss, oset, sizeof(olss));
    377 		if (error)
    378 			return (error);
    379 	}
    380 	return (error);
    381 }
    382 
    383 int
    384 linux_sys_rt_sigprocmask(l, v, retval)
    385 	struct lwp *l;
    386 	void *v;
    387 	register_t *retval;
    388 {
    389 	struct linux_sys_rt_sigprocmask_args /* {
    390 		syscallarg(int) how;
    391 		syscallarg(const linux_sigset_t *) set;
    392 		syscallarg(linux_sigset_t *) oset;
    393 		syscallarg(size_t) sigsetsize;
    394 	} */ *uap = v;
    395 	struct proc *p = l->l_proc;
    396 	linux_sigset_t nlss, olss, *oset;
    397 	const linux_sigset_t *set;
    398 	sigset_t nbss, obss;
    399 	int error, how;
    400 
    401 	if (SCARG(uap, sigsetsize) != sizeof(linux_sigset_t))
    402 		return (EINVAL);
    403 
    404 	switch (SCARG(uap, how)) {
    405 	case LINUX_SIG_BLOCK:
    406 		how = SIG_BLOCK;
    407 		break;
    408 	case LINUX_SIG_UNBLOCK:
    409 		how = SIG_UNBLOCK;
    410 		break;
    411 	case LINUX_SIG_SETMASK:
    412 		how = SIG_SETMASK;
    413 		break;
    414 	default:
    415 		return (EINVAL);
    416 	}
    417 
    418 	set = SCARG(uap, set);
    419 	oset = SCARG(uap, oset);
    420 
    421 	if (set) {
    422 		error = copyin(set, &nlss, sizeof(nlss));
    423 		if (error)
    424 			return (error);
    425 		linux_to_native_sigset(&nbss, &nlss);
    426 	}
    427 	error = sigprocmask1(p, how,
    428 	    set ? &nbss : NULL, oset ? &obss : NULL);
    429 	if (!error && oset) {
    430 		native_to_linux_sigset(&olss, &obss);
    431 		error = copyout(&olss, oset, sizeof(olss));
    432 	}
    433 	return (error);
    434 }
    435 
    436 int
    437 linux_sys_rt_sigpending(l, v, retval)
    438 	struct lwp *l;
    439 	void *v;
    440 	register_t *retval;
    441 {
    442 	struct linux_sys_rt_sigpending_args /* {
    443 		syscallarg(linux_sigset_t *) set;
    444 		syscallarg(size_t) sigsetsize;
    445 	} */ *uap = v;
    446 	struct proc *p = l->l_proc;
    447 	sigset_t bss;
    448 	linux_sigset_t lss;
    449 
    450 	if (SCARG(uap, sigsetsize) != sizeof(linux_sigset_t))
    451 		return (EINVAL);
    452 
    453 	sigpending1(p, &bss);
    454 	native_to_linux_sigset(&lss, &bss);
    455 	return copyout(&lss, SCARG(uap, set), sizeof(lss));
    456 }
    457 
    458 int
    459 linux_sys_sigpending(l, v, retval)
    460 	struct lwp *l;
    461 	void *v;
    462 	register_t *retval;
    463 {
    464 	struct linux_sys_sigpending_args /* {
    465 		syscallarg(linux_old_sigset_t *) mask;
    466 	} */ *uap = v;
    467 	struct proc *p = l->l_proc;
    468 	sigset_t bss;
    469 	linux_old_sigset_t lss;
    470 
    471 	sigpending1(p, &bss);
    472 	native_to_linux_old_sigset(&lss, &bss);
    473 	return copyout(&lss, SCARG(uap, set), sizeof(lss));
    474 }
    475 
    476 int
    477 linux_sys_sigsuspend(l, v, retval)
    478 	struct lwp *l;
    479 	void *v;
    480 	register_t *retval;
    481 {
    482 	struct linux_sys_sigsuspend_args /* {
    483 		syscallarg(caddr_t) restart;
    484 		syscallarg(int) oldmask;
    485 		syscallarg(int) mask;
    486 	} */ *uap = v;
    487 	struct proc *p = l->l_proc;
    488 	linux_old_sigset_t lss;
    489 	sigset_t bss;
    490 
    491 	lss = SCARG(uap, mask);
    492 	linux_old_to_native_sigset(&bss, &lss);
    493 	return (sigsuspend1(p, &bss));
    494 }
    495 int
    496 linux_sys_rt_sigsuspend(l, v, retval)
    497 	struct lwp *l;
    498 	void *v;
    499 	register_t *retval;
    500 {
    501 	struct linux_sys_rt_sigsuspend_args /* {
    502 		syscallarg(linux_sigset_t *) unewset;
    503 		syscallarg(size_t) sigsetsize;
    504 	} */ *uap = v;
    505 	struct proc *p = l->l_proc;
    506 	linux_sigset_t lss;
    507 	sigset_t bss;
    508 	int error;
    509 
    510 	if (SCARG(uap, sigsetsize) != sizeof(linux_sigset_t))
    511 		return (EINVAL);
    512 
    513 	error = copyin(SCARG(uap, unewset), &lss, sizeof(linux_sigset_t));
    514 	if (error)
    515 		return (error);
    516 
    517 	linux_to_native_sigset(&bss, &lss);
    518 
    519 	return (sigsuspend1(p, &bss));
    520 }
    521 
    522 /*
    523  * Once more: only a signal conversion is needed.
    524  * Note: also used as sys_rt_queueinfo.  The info field is ignored.
    525  */
    526 int
    527 linux_sys_rt_queueinfo(l, v, retval)
    528 	struct lwp *l;
    529 	void *v;
    530 	register_t *retval;
    531 {
    532 	/* XXX XAX This isn't this really int, int, siginfo_t *, is it? */
    533 #if 0
    534 	struct linux_sys_rt_queueinfo_args /* {
    535 		syscallarg(int) pid;
    536 		syscallarg(int) signum;
    537 		syscallarg(siginfo_t *) uinfo;
    538 	} */ *uap = v;
    539 #endif
    540 
    541 	/* XXX To really implement this we need to	*/
    542 	/* XXX keep a list of queued signals somewhere.	*/
    543 	return (linux_sys_kill(l, v, retval));
    544 }
    545 
    546 int
    547 linux_sys_kill(l, v, retval)
    548 	struct lwp *l;
    549 	void *v;
    550 	register_t *retval;
    551 {
    552 	struct linux_sys_kill_args /* {
    553 		syscallarg(int) pid;
    554 		syscallarg(int) signum;
    555 	} */ *uap = v;
    556 
    557 	struct sys_kill_args ka;
    558 	int sig;
    559 
    560 	SCARG(&ka, pid) = SCARG(uap, pid);
    561 	sig = SCARG(uap, signum);
    562 	if (sig < 0 || sig >= LINUX__NSIG)
    563 		return (EINVAL);
    564 	SCARG(&ka, signum) = linux_to_native_signo[sig];
    565 	return sys_kill(l, &ka, retval);
    566 }
    567 
    568 #ifdef LINUX_SS_ONSTACK
    569 static void linux_to_native_sigaltstack __P((struct sigaltstack *,
    570     const struct linux_sigaltstack *));
    571 static void native_to_linux_sigaltstack __P((struct linux_sigaltstack *,
    572     const struct sigaltstack *));
    573 
    574 static void
    575 linux_to_native_sigaltstack(bss, lss)
    576 	struct sigaltstack *bss;
    577 	const struct linux_sigaltstack *lss;
    578 {
    579 	bss->ss_sp = lss->ss_sp;
    580 	bss->ss_size = lss->ss_size;
    581 	if (lss->ss_flags & LINUX_SS_ONSTACK)
    582 	    bss->ss_flags = SS_ONSTACK;
    583 	else if (lss->ss_flags & LINUX_SS_DISABLE)
    584 	    bss->ss_flags = SS_DISABLE;
    585 	else
    586 	    bss->ss_flags = 0;
    587 }
    588 
    589 static void
    590 native_to_linux_sigaltstack(lss, bss)
    591 	struct linux_sigaltstack *lss;
    592 	const struct sigaltstack *bss;
    593 {
    594 	lss->ss_sp = bss->ss_sp;
    595 	lss->ss_size = bss->ss_size;
    596 	if (bss->ss_flags & SS_ONSTACK)
    597 	    lss->ss_flags = LINUX_SS_ONSTACK;
    598 	else if (bss->ss_flags & SS_DISABLE)
    599 	    lss->ss_flags = LINUX_SS_DISABLE;
    600 	else
    601 	    lss->ss_flags = 0;
    602 }
    603 
    604 int
    605 linux_sys_sigaltstack(l, v, retval)
    606 	struct lwp *l;
    607 	void *v;
    608 	register_t *retval;
    609 {
    610 	struct linux_sys_sigaltstack_args /* {
    611 		syscallarg(const struct linux_sigaltstack *) ss;
    612 		syscallarg(struct linux_sigaltstack *) oss;
    613 	} */ *uap = v;
    614 	struct proc *p = l->l_proc;
    615 	struct linux_sigaltstack ss;
    616 	struct sigaltstack nss, oss;
    617 	int error;
    618 
    619 	if (SCARG(uap, ss) != NULL) {
    620 		if ((error = copyin(SCARG(uap, ss), &ss, sizeof(ss))) != 0)
    621 			return error;
    622 		linux_to_native_sigaltstack(&nss, &ss);
    623 	}
    624 
    625 	error = sigaltstack1(p,
    626 	    SCARG(uap, ss) ? &nss : NULL, SCARG(uap, oss) ? &oss : NULL);
    627 	if (error)
    628 		return error;
    629 
    630 	if (SCARG(uap, oss) != NULL) {
    631 		native_to_linux_sigaltstack(&ss, &oss);
    632 		if ((error = copyout(&ss, SCARG(uap, oss), sizeof(ss))) != 0)
    633 			return error;
    634 	}
    635 	return 0;
    636 }
    637 #endif
    638