1/*
2 * Copyright (c) 1991, 1992 Paul Kranenburg <pk@cs.few.eur.nl>
3 * Copyright (c) 1993 Branko Lankester <branko@hacktic.nl>
4 * Copyright (c) 1993, 1994, 1995, 1996 Rick Sladkey <jrs@world.std.com>
5 * Copyright (c) 1996-1999 Wichert Akkerman <wichert@cistron.nl>
6 * Copyright (c) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
7 *                     Linux for s390 port by D.J. Barrow
8 *                    <barrow_dj@mail.yahoo.com,djbarrow@de.ibm.com>
9 * Copyright (c) 2001-2018 The strace developers.
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 *    notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 *    notice, this list of conditions and the following disclaimer in the
19 *    documentation and/or other materials provided with the distribution.
20 * 3. The name of the author may not be used to endorse or promote products
21 *    derived from this software without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 */
34
35#include "defs.h"
36#include "nsig.h"
37#include "xstring.h"
38
39/* The libc headers do not define this constant since it should only be
40   used by the implementation.  So we define it here.  */
41#ifndef SA_RESTORER
42# ifdef ASM_SA_RESTORER
43#  define SA_RESTORER ASM_SA_RESTORER
44# endif
45#endif
46
47/*
48 * Some architectures define SA_RESTORER in their headers,
49 * but do not actually have sa_restorer.
50 *
51 * Some architectures, otherwise, do not define SA_RESTORER in their headers,
52 * but actually have sa_restorer.
53 */
54#ifdef HAVE_ARCH_SA_RESTORER
55# define HAVE_SA_RESTORER HAVE_ARCH_SA_RESTORER
56#else /* !HAVE_ARCH_SA_RESTORER */
57# ifdef SA_RESTORER
58#  define HAVE_SA_RESTORER 1
59# else
60#  define HAVE_SA_RESTORER 0
61# endif
62#endif /* HAVE_ARCH_SA_RESTORER */
63
64#include "xlat/sa_handler_values.h"
65#include "xlat/sigact_flags.h"
66#include "xlat/sigprocmaskcmds.h"
67
68/* Anonymous realtime signals. */
69#ifndef ASM_SIGRTMIN
70/* Linux kernel >= 3.18 defines SIGRTMIN to 32 on all architectures. */
71# define ASM_SIGRTMIN 32
72#endif
73#ifndef ASM_SIGRTMAX
74/* Under glibc 2.1, SIGRTMAX et al are functions, but __SIGRTMAX is a
75   constant.  This is what we want.  Otherwise, just use SIGRTMAX. */
76# ifdef SIGRTMAX
77#  ifndef __SIGRTMAX
78#   define __SIGRTMAX SIGRTMAX
79#  endif
80# endif
81# ifdef __SIGRTMAX
82#  define ASM_SIGRTMAX __SIGRTMAX
83# endif
84#endif
85
86/* Note on the size of sigset_t:
87 *
88 * In glibc, sigset_t is an array with space for 1024 bits (!),
89 * even though all arches supported by Linux have only 64 signals
90 * except MIPS, which has 128. IOW, it is 128 bytes long.
91 *
92 * In-kernel sigset_t is sized correctly (it is either 64 or 128 bit long).
93 * However, some old syscall return only 32 lower bits (one word).
94 * Example: sys_sigpending vs sys_rt_sigpending.
95 *
96 * Be aware of this fact when you try to
97 *     memcpy(&tcp->u_arg[1], &something, sizeof(sigset_t))
98 * - sizeof(sigset_t) is much bigger than you think,
99 * it may overflow tcp->u_arg[] array, and it may try to copy more data
100 * than is really available in <something>.
101 * Similarly,
102 *     umoven(tcp, addr, sizeof(sigset_t), &sigset)
103 * may be a bad idea: it'll try to read much more data than needed
104 * to fetch a sigset_t.
105 * Use NSIG_BYTES as a size instead.
106 */
107
108static const char *
109get_sa_handler_str(kernel_ulong_t handler)
110{
111	return xlookup(sa_handler_values, handler);
112}
113
114static void
115print_sa_handler(kernel_ulong_t handler)
116{
117	const char *sa_handler_str = get_sa_handler_str(handler);
118
119	if (sa_handler_str)
120		tprints(sa_handler_str);
121	else
122		printaddr(handler);
123}
124
125const char *
126signame(const int sig)
127{
128	static char buf[sizeof("SIGRT_%u") + sizeof(int)*3];
129
130	if (sig >= 0) {
131		const unsigned int s = sig;
132
133		if (s < nsignals)
134			return signalent[s];
135#ifdef ASM_SIGRTMAX
136		if (s >= ASM_SIGRTMIN && s <= (unsigned int) ASM_SIGRTMAX) {
137			xsprintf(buf, "SIGRT_%u", s - ASM_SIGRTMIN);
138			return buf;
139		}
140#endif
141	}
142	xsprintf(buf, "%d", sig);
143	return buf;
144}
145
146static unsigned int
147popcount32(const uint32_t *a, unsigned int size)
148{
149	unsigned int count = 0;
150
151	for (; size; ++a, --size) {
152		uint32_t x = *a;
153
154#ifdef HAVE___BUILTIN_POPCOUNT
155		count += __builtin_popcount(x);
156#else
157		for (; x; ++count)
158			x &= x - 1;
159#endif
160	}
161
162	return count;
163}
164
165const char *
166sprintsigmask_n(const char *prefix, const void *sig_mask, unsigned int bytes)
167{
168	/*
169	 * The maximum number of signal names to be printed
170	 * is NSIG_BYTES * 8 * 2 / 3.
171	 * Most of signal names have length 7,
172	 * average length of signal names is less than 7.
173	 * The length of prefix string does not exceed 16.
174	 */
175	static char outstr[128 + 8 * (NSIG_BYTES * 8 * 2 / 3)];
176
177	char *s;
178	const uint32_t *mask;
179	uint32_t inverted_mask[NSIG_BYTES / 4];
180	unsigned int size;
181	int i;
182	char sep;
183
184	s = stpcpy(outstr, prefix);
185
186	mask = sig_mask;
187	/* length of signal mask in 4-byte words */
188	size = (bytes >= NSIG_BYTES) ? NSIG_BYTES / 4 : (bytes + 3) / 4;
189
190	/* check whether 2/3 or more bits are set */
191	if (popcount32(mask, size) >= size * (4 * 8) * 2 / 3) {
192		/* show those signals that are NOT in the mask */
193		unsigned int j;
194		for (j = 0; j < size; ++j)
195			inverted_mask[j] = ~mask[j];
196		mask = inverted_mask;
197		*s++ = '~';
198	}
199
200	sep = '[';
201	for (i = 0; (i = next_set_bit(mask, i, size * (4 * 8))) >= 0; ) {
202		++i;
203		*s++ = sep;
204		if ((unsigned) i < nsignals) {
205			s = stpcpy(s, signalent[i] + 3);
206		}
207#ifdef ASM_SIGRTMAX
208		else if (i >= ASM_SIGRTMIN && i <= ASM_SIGRTMAX) {
209			s = xappendstr(outstr, s, "RT_%u", i - ASM_SIGRTMIN);
210		}
211#endif
212		else {
213			s = xappendstr(outstr, s, "%u", i);
214		}
215		sep = ' ';
216	}
217	if (sep == '[')
218		*s++ = sep;
219	*s++ = ']';
220	*s = '\0';
221	return outstr;
222}
223
224#define sprintsigmask_val(prefix, mask) \
225	sprintsigmask_n((prefix), &(mask), sizeof(mask))
226
227#define tprintsigmask_val(prefix, mask) \
228	tprints(sprintsigmask_n((prefix), &(mask), sizeof(mask)))
229
230static const char *
231sprint_old_sigmask_val(const char *const prefix, const unsigned long mask)
232{
233#if defined(current_wordsize) || !defined(WORDS_BIGENDIAN)
234	return sprintsigmask_n(prefix, &mask, current_wordsize);
235#else /* !current_wordsize && WORDS_BIGENDIAN */
236	if (current_wordsize == sizeof(mask)) {
237		return sprintsigmask_val(prefix, mask);
238	} else {
239		uint32_t mask32 = mask;
240		return sprintsigmask_val(prefix, mask32);
241	}
242#endif
243}
244
245#define tprint_old_sigmask_val(prefix, mask) \
246	tprints(sprint_old_sigmask_val((prefix), (mask)))
247
248void
249printsignal(int nr)
250{
251	tprints(signame(nr));
252}
253
254static void
255print_sigset_addr_len_limit(struct tcb *const tcp, const kernel_ulong_t addr,
256			    const kernel_ulong_t len, const unsigned int min_len)
257{
258	/*
259	 * Here len is usually equal to NSIG_BYTES or current_wordsize.
260	 * But we code this defensively:
261	 */
262	if (len < min_len || len > NSIG_BYTES) {
263		printaddr(addr);
264		return;
265	}
266	int mask[NSIG_BYTES / sizeof(int)] = {};
267	if (umoven_or_printaddr(tcp, addr, len, mask))
268		return;
269	tprints(sprintsigmask_n("", mask, len));
270}
271
272void
273print_sigset_addr_len(struct tcb *const tcp, const kernel_ulong_t addr,
274		      const kernel_ulong_t len)
275{
276	print_sigset_addr_len_limit(tcp, addr, len, current_wordsize);
277}
278
279void
280print_sigset_addr(struct tcb *const tcp, const kernel_ulong_t addr)
281{
282	print_sigset_addr_len_limit(tcp, addr, NSIG_BYTES, NSIG_BYTES);
283}
284
285SYS_FUNC(ssetmask)
286{
287	if (entering(tcp)) {
288		tprint_old_sigmask_val("", (unsigned) tcp->u_arg[0]);
289	} else if (!syserror(tcp)) {
290		tcp->auxstr = sprint_old_sigmask_val("old mask ",
291						     (unsigned) tcp->u_rval);
292		return RVAL_HEX | RVAL_STR;
293	}
294	return 0;
295}
296
297struct old_sigaction {
298	/* sa_handler may be a libc #define, need to use other name: */
299#if defined MIPS
300	unsigned int sa_flags;
301	unsigned long sa_handler__;
302	unsigned long sa_mask;
303#elif defined ALPHA
304	unsigned long sa_handler__;
305	unsigned long sa_mask;
306	unsigned int sa_flags;
307#else
308	unsigned long sa_handler__;
309	unsigned long sa_mask;
310	unsigned long sa_flags;
311	unsigned long sa_restorer;
312#endif
313}
314#ifdef ALPHA
315	ATTRIBUTE_PACKED
316#endif
317;
318
319static void
320decode_old_sigaction(struct tcb *const tcp, const kernel_ulong_t addr)
321{
322	struct old_sigaction sa;
323
324#ifndef current_wordsize
325	if (current_wordsize < sizeof(sa.sa_handler__)) {
326		struct old_sigaction32 {
327			uint32_t sa_handler__;
328			uint32_t sa_mask;
329			uint32_t sa_flags;
330			uint32_t sa_restorer;
331		} sa32;
332
333		if (umove_or_printaddr(tcp, addr, &sa32))
334			return;
335
336		memset(&sa, 0, sizeof(sa));
337		sa.sa_handler__ = sa32.sa_handler__;
338		sa.sa_flags = sa32.sa_flags;
339		sa.sa_restorer = sa32.sa_restorer;
340		sa.sa_mask = sa32.sa_mask;
341	} else
342#endif
343	if (umove_or_printaddr(tcp, addr, &sa))
344		return;
345
346	tprints("{sa_handler=");
347	print_sa_handler(sa.sa_handler__);
348	tprints(", sa_mask=");
349	tprint_old_sigmask_val("", sa.sa_mask);
350	tprints(", sa_flags=");
351	printflags(sigact_flags, sa.sa_flags, "SA_???");
352#if !(defined ALPHA || defined MIPS)
353	if (sa.sa_flags & 0x04000000U) {
354		tprints(", sa_restorer=");
355		printaddr(sa.sa_restorer);
356	}
357#endif
358	tprints("}");
359}
360
361SYS_FUNC(sigaction)
362{
363	if (entering(tcp)) {
364		int signo = tcp->u_arg[0];
365#if defined SPARC || defined SPARC64
366		if (signo < 0) {
367			tprints("-");
368			signo = -signo;
369		}
370#endif
371		printsignal(signo);
372		tprints(", ");
373		decode_old_sigaction(tcp, tcp->u_arg[1]);
374		tprints(", ");
375	} else
376		decode_old_sigaction(tcp, tcp->u_arg[2]);
377	return 0;
378}
379
380SYS_FUNC(signal)
381{
382	if (entering(tcp)) {
383		printsignal(tcp->u_arg[0]);
384		tprints(", ");
385		print_sa_handler(tcp->u_arg[1]);
386		return 0;
387	} else if (!syserror(tcp)) {
388		tcp->auxstr = get_sa_handler_str(tcp->u_rval);
389		return RVAL_HEX | RVAL_STR;
390	}
391	return 0;
392}
393
394SYS_FUNC(sgetmask)
395{
396	if (exiting(tcp) && !syserror(tcp)) {
397		tcp->auxstr = sprint_old_sigmask_val("mask ", tcp->u_rval);
398		return RVAL_HEX | RVAL_STR;
399	}
400	return 0;
401}
402
403SYS_FUNC(sigsuspend)
404{
405#ifdef MIPS
406	print_sigset_addr_len(tcp, tcp->u_arg[tcp->s_ent->nargs - 1],
407			      current_wordsize);
408#else
409	tprint_old_sigmask_val("", tcp->u_arg[tcp->s_ent->nargs - 1]);
410#endif
411
412	return RVAL_DECODED;
413}
414
415#ifdef ALPHA
416/*
417 * The OSF/1 sigprocmask is different: it doesn't pass in two pointers,
418 * but rather passes in the new bitmask as an argument and then returns
419 * the old bitmask.  This "works" because we only have 64 signals to worry
420 * about.  If you want more, use of the rt_sigprocmask syscall is required.
421 *
422 * Alpha:
423 *	old = osf_sigprocmask(how, new);
424 * Everyone else:
425 *	ret = sigprocmask(how, &new, &old, ...);
426 */
427SYS_FUNC(osf_sigprocmask)
428{
429	if (entering(tcp)) {
430		printxval(sigprocmaskcmds, tcp->u_arg[0], "SIG_???");
431		tprintsigmask_val(", ", tcp->u_arg[1]);
432	} else if (!syserror(tcp)) {
433		tcp->auxstr = sprintsigmask_val("old mask ", tcp->u_rval);
434		return RVAL_HEX | RVAL_STR;
435	}
436	return 0;
437}
438
439#else /* !ALPHA */
440
441/* "Old" sigprocmask, which operates with word-sized signal masks */
442SYS_FUNC(sigprocmask)
443{
444	if (entering(tcp)) {
445		printxval(sigprocmaskcmds, tcp->u_arg[0], "SIG_???");
446		tprints(", ");
447		print_sigset_addr_len(tcp, tcp->u_arg[1], current_wordsize);
448		tprints(", ");
449	} else {
450		print_sigset_addr_len(tcp, tcp->u_arg[2], current_wordsize);
451	}
452	return 0;
453}
454#endif /* !ALPHA */
455
456SYS_FUNC(kill)
457{
458	tprintf("%d, %s",
459		(int) tcp->u_arg[0],
460		signame(tcp->u_arg[1]));
461
462	return RVAL_DECODED;
463}
464
465SYS_FUNC(tgkill)
466{
467	tprintf("%d, %d, %s",
468		(int) tcp->u_arg[0],
469		(int) tcp->u_arg[1],
470		signame(tcp->u_arg[2]));
471
472	return RVAL_DECODED;
473}
474
475SYS_FUNC(sigpending)
476{
477	if (exiting(tcp))
478		print_sigset_addr_len(tcp, tcp->u_arg[0], current_wordsize);
479	return 0;
480}
481
482SYS_FUNC(rt_sigprocmask)
483{
484	/* Note: arg[3] is the length of the sigset. Kernel requires NSIG_BYTES */
485	if (entering(tcp)) {
486		printxval(sigprocmaskcmds, tcp->u_arg[0], "SIG_???");
487		tprints(", ");
488		print_sigset_addr_len(tcp, tcp->u_arg[1], tcp->u_arg[3]);
489		tprints(", ");
490	} else {
491		print_sigset_addr_len(tcp, tcp->u_arg[2], tcp->u_arg[3]);
492		tprintf(", %" PRI_klu, tcp->u_arg[3]);
493	}
494	return 0;
495}
496
497/* Structure describing the action to be taken when a signal arrives.  */
498struct new_sigaction {
499	/* sa_handler may be a libc #define, need to use other name: */
500#ifdef MIPS
501	unsigned int sa_flags;
502	unsigned long sa_handler__;
503#else
504	unsigned long sa_handler__;
505	unsigned long sa_flags;
506#endif /* !MIPS */
507#if HAVE_SA_RESTORER
508	unsigned long sa_restorer;
509#endif
510	/* Kernel treats sa_mask as an array of longs. */
511	unsigned long sa_mask[NSIG / sizeof(long)];
512};
513/* Same for i386-on-x86_64 and similar cases */
514struct new_sigaction32 {
515	uint32_t sa_handler__;
516	uint32_t sa_flags;
517#if HAVE_SA_RESTORER
518	uint32_t sa_restorer;
519#endif
520	uint32_t sa_mask[2 * (NSIG / sizeof(long))];
521};
522
523static void
524decode_new_sigaction(struct tcb *const tcp, const kernel_ulong_t addr)
525{
526	struct new_sigaction sa;
527
528#ifndef current_wordsize
529	if (current_wordsize < sizeof(sa.sa_handler__)) {
530		struct new_sigaction32 sa32;
531
532		if (umove_or_printaddr(tcp, addr, &sa32))
533			return;
534
535		memset(&sa, 0, sizeof(sa));
536		sa.sa_handler__ = sa32.sa_handler__;
537		sa.sa_flags     = sa32.sa_flags;
538#if HAVE_SA_RESTORER && defined SA_RESTORER
539		sa.sa_restorer  = sa32.sa_restorer;
540#endif
541		/* Kernel treats sa_mask as an array of longs.
542		 * For 32-bit process, "long" is uint32_t, thus, for example,
543		 * 32th bit in sa_mask will end up as bit 0 in sa_mask[1].
544		 * But for (64-bit) kernel, 32th bit in sa_mask is
545		 * 32th bit in 0th (64-bit) long!
546		 * For little-endian, it's the same.
547		 * For big-endian, we swap 32-bit words.
548		 */
549		sa.sa_mask[0] = ULONG_LONG(sa32.sa_mask[0], sa32.sa_mask[1]);
550	} else
551#endif
552	if (umove_or_printaddr(tcp, addr, &sa))
553		return;
554
555	tprints("{sa_handler=");
556	print_sa_handler(sa.sa_handler__);
557	tprints(", sa_mask=");
558	/*
559	 * Sigset size is in tcp->u_arg[4] (SPARC)
560	 * or in tcp->u_arg[3] (all other),
561	 * but kernel won't handle sys_rt_sigaction
562	 * with wrong sigset size (just returns EINVAL instead).
563	 * We just fetch the right size, which is NSIG_BYTES.
564	 */
565	tprintsigmask_val("", sa.sa_mask);
566	tprints(", sa_flags=");
567
568	printflags(sigact_flags, sa.sa_flags, "SA_???");
569#if HAVE_SA_RESTORER && defined SA_RESTORER
570	if (sa.sa_flags & SA_RESTORER) {
571		tprints(", sa_restorer=");
572		printaddr(sa.sa_restorer);
573	}
574#endif
575	tprints("}");
576}
577
578SYS_FUNC(rt_sigaction)
579{
580	if (entering(tcp)) {
581		printsignal(tcp->u_arg[0]);
582		tprints(", ");
583		decode_new_sigaction(tcp, tcp->u_arg[1]);
584		tprints(", ");
585	} else {
586		decode_new_sigaction(tcp, tcp->u_arg[2]);
587#if defined(SPARC) || defined(SPARC64)
588		tprintf(", %#" PRI_klx ", %" PRI_klu, tcp->u_arg[3], tcp->u_arg[4]);
589#elif defined(ALPHA)
590		tprintf(", %" PRI_klu ", %#" PRI_klx, tcp->u_arg[3], tcp->u_arg[4]);
591#else
592		tprintf(", %" PRI_klu, tcp->u_arg[3]);
593#endif
594	}
595	return 0;
596}
597
598SYS_FUNC(rt_sigpending)
599{
600	if (exiting(tcp)) {
601		/*
602		 * One of the few syscalls where sigset size (arg[1])
603		 * is allowed to be <= NSIG_BYTES, not strictly ==.
604		 * This allows non-rt sigpending() syscall
605		 * to reuse rt_sigpending() code in kernel.
606		 */
607		print_sigset_addr_len_limit(tcp, tcp->u_arg[0],
608					    tcp->u_arg[1], 1);
609		tprintf(", %" PRI_klu, tcp->u_arg[1]);
610	}
611	return 0;
612}
613
614SYS_FUNC(rt_sigsuspend)
615{
616	/* NB: kernel requires arg[1] == NSIG_BYTES */
617	print_sigset_addr_len(tcp, tcp->u_arg[0], tcp->u_arg[1]);
618	tprintf(", %" PRI_klu, tcp->u_arg[1]);
619
620	return RVAL_DECODED;
621}
622
623static void
624print_sigqueueinfo(struct tcb *const tcp, const int sig,
625		   const kernel_ulong_t addr)
626{
627	printsignal(sig);
628	tprints(", ");
629	printsiginfo_at(tcp, addr);
630}
631
632SYS_FUNC(rt_sigqueueinfo)
633{
634	tprintf("%d, ", (int) tcp->u_arg[0]);
635	print_sigqueueinfo(tcp, tcp->u_arg[1], tcp->u_arg[2]);
636
637	return RVAL_DECODED;
638}
639
640SYS_FUNC(rt_tgsigqueueinfo)
641{
642	tprintf("%d, %d, ", (int) tcp->u_arg[0], (int) tcp->u_arg[1]);
643	print_sigqueueinfo(tcp, tcp->u_arg[2], tcp->u_arg[3]);
644
645	return RVAL_DECODED;
646}
647
648SYS_FUNC(rt_sigtimedwait)
649{
650	/* NB: kernel requires arg[3] == NSIG_BYTES */
651	if (entering(tcp)) {
652		print_sigset_addr_len(tcp, tcp->u_arg[0], tcp->u_arg[3]);
653		tprints(", ");
654		if (!(tcp->u_arg[1] && verbose(tcp))) {
655			/*
656			 * This is the only "return" parameter,
657			 * if we are not going to fetch it on exit,
658			 * decode all parameters on entry.
659			 */
660			printaddr(tcp->u_arg[1]);
661			tprints(", ");
662			print_timespec(tcp, tcp->u_arg[2]);
663			tprintf(", %" PRI_klu, tcp->u_arg[3]);
664		} else {
665			char *sts = xstrdup(sprint_timespec(tcp, tcp->u_arg[2]));
666			set_tcb_priv_data(tcp, sts, free);
667		}
668	} else {
669		if (tcp->u_arg[1] && verbose(tcp)) {
670			printsiginfo_at(tcp, tcp->u_arg[1]);
671			tprints(", ");
672			tprints(get_tcb_priv_data(tcp));
673			tprintf(", %" PRI_klu, tcp->u_arg[3]);
674		}
675
676		if (!syserror(tcp) && tcp->u_rval) {
677			tcp->auxstr = signame(tcp->u_rval);
678			return RVAL_STR;
679		}
680	}
681	return 0;
682}
683
684SYS_FUNC(restart_syscall)
685{
686	tprintf("<... resuming interrupted %s ...>",
687		tcp->s_prev_ent ? tcp->s_prev_ent->sys_name : "system call");
688
689	return RVAL_DECODED;
690}
691