xref: /qemu/linux-user/signal.c (revision 66fb9763af9cd743158957e8c9c2559d922b1c22)
1 /*
2  *  Emulation of Linux signals
3  *
4  *  Copyright (c) 2003 Fabrice Bellard
5  *
6  *  This program is free software; you can redistribute it and/or modify
7  *  it under the terms of the GNU General Public License as published by
8  *  the Free Software Foundation; either version 2 of the License, or
9  *  (at your option) any later version.
10  *
11  *  This program is distributed in the hope that it will be useful,
12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *  GNU General Public License for more details.
15  *
16  *  You should have received a copy of the GNU General Public License
17  *  along with this program; if not, write to the Free Software
18  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19  */
20 #include <stdlib.h>
21 #include <stdio.h>
22 #include <string.h>
23 #include <stdarg.h>
24 #include <signal.h>
25 #include <errno.h>
26 #include <sys/ucontext.h>
27 
28 #include "gemu.h"
29 
30 #include "syscall_defs.h"
31 
32 #ifdef TARGET_I386
33 #include "cpu-i386.h"
34 #include "syscall-i386.h"
35 #endif
36 
37 /* signal handling inspired from em86. */
38 
39 //#define DEBUG_SIGNAL
40 
41 #define MAX_SIGQUEUE_SIZE 1024
42 
43 struct sigqueue {
44     struct sigqueue *next;
45     siginfo_t info;
46 };
47 
48 struct emulated_sigaction {
49     struct target_sigaction sa;
50     int pending; /* true if signal is pending */
51     struct sigqueue *first;
52     struct sigqueue info; /* in order to always have memory for the
53                              first signal, we put it here */
54 };
55 
56 static struct emulated_sigaction sigact_table[TARGET_NSIG];
57 static struct sigqueue sigqueue_table[MAX_SIGQUEUE_SIZE]; /* siginfo queue */
58 static struct sigqueue *first_free; /* first free siginfo queue entry */
59 static int signal_pending; /* non zero if a signal may be pending */
60 
61 static void host_signal_handler(int host_signum, siginfo_t *info,
62                                 void *puc);
63 
64 /* XXX: do it properly */
65 static inline int host_to_target_signal(int sig)
66 {
67     return sig;
68 }
69 
70 static inline int target_to_host_signal(int sig)
71 {
72     return sig;
73 }
74 
75 void host_to_target_sigset(target_sigset_t *d, sigset_t *s)
76 {
77     int i;
78     for(i = 0;i < TARGET_NSIG_WORDS; i++) {
79         d->sig[i] = tswapl(((unsigned long *)s)[i]);
80     }
81 }
82 
83 void target_to_host_sigset(sigset_t *d, target_sigset_t *s)
84 {
85     int i;
86     for(i = 0;i < TARGET_NSIG_WORDS; i++) {
87         ((unsigned long *)d)[i] = tswapl(s->sig[i]);
88     }
89 }
90 
91 void host_to_target_old_sigset(target_ulong *old_sigset,
92                                const sigset_t *sigset)
93 {
94     *old_sigset = tswap32(*(unsigned long *)sigset & 0xffffffff);
95 }
96 
97 void target_to_host_old_sigset(sigset_t *sigset,
98                                const target_ulong *old_sigset)
99 {
100     sigemptyset(sigset);
101     *(unsigned long *)sigset = tswapl(*old_sigset);
102 }
103 
104 /* XXX: finish it */
105 void host_to_target_siginfo(target_siginfo_t *tinfo, siginfo_t *info)
106 {
107     tinfo->si_signo = tswap32(info->si_signo);
108     tinfo->si_errno = tswap32(info->si_errno);
109     tinfo->si_code = tswap32(info->si_code);
110 }
111 
112 /* XXX: finish it */
113 void target_to_host_siginfo(siginfo_t *info, target_siginfo_t *tinfo)
114 {
115     info->si_signo = tswap32(tinfo->si_signo);
116     info->si_errno = tswap32(tinfo->si_errno);
117     info->si_code = tswap32(tinfo->si_code);
118 }
119 
120 void signal_init(void)
121 {
122     struct sigaction act;
123     int i;
124 
125     /* set all host signal handlers */
126     sigemptyset(&act.sa_mask);
127     act.sa_flags = SA_SIGINFO;
128     act.sa_sigaction = host_signal_handler;
129     for(i = 1; i < NSIG; i++) {
130 	sigaction(i, &act, NULL);
131     }
132 
133     memset(sigact_table, 0, sizeof(sigact_table));
134 
135     first_free = &sigqueue_table[0];
136     for(i = 0; i < MAX_SIGQUEUE_SIZE - 1; i++)
137         sigqueue_table[i].next = &sigqueue_table[i + 1];
138     sigqueue_table[MAX_SIGQUEUE_SIZE - 1].next = NULL;
139 }
140 
141 /* signal queue handling */
142 
143 static inline struct sigqueue *alloc_sigqueue(void)
144 {
145     struct sigqueue *q = first_free;
146     if (!q)
147         return NULL;
148     first_free = q->next;
149     return q;
150 }
151 
152 static inline void free_sigqueue(struct sigqueue *q)
153 {
154     q->next = first_free;
155     first_free = q;
156 }
157 
158 static int queue_signal(struct emulated_sigaction *k, int sig, siginfo_t *info)
159 {
160     struct sigqueue *q, **pq;
161 
162     pq = &k->first;
163     if (!k->pending || sig < TARGET_SIGRTMIN) {
164         /* first signal or non real time signal */
165         q = &k->info;
166     } else {
167         q = alloc_sigqueue();
168         if (!q)
169             return -EAGAIN;
170         while (*pq != NULL)
171             pq = &(*pq)->next;
172     }
173     *pq = q;
174     q->info = *info;
175     q->next = NULL;
176     k->pending = 1;
177     /* signal that a new signal is pending */
178     signal_pending = 1;
179     return 0;
180 }
181 
182 void force_sig(int sig)
183 {
184     int host_sig;
185     /* abort execution with signal */
186     host_sig = target_to_host_signal(sig);
187     fprintf(stderr, "gemu: uncaught target signal %d (%s) - exiting\n",
188             sig, strsignal(host_sig));
189     _exit(-host_sig);
190 }
191 
192 
193 static void host_signal_handler(int host_signum, siginfo_t *info,
194                                 void *puc)
195 {
196     struct emulated_sigaction *k;
197     int sig;
198     target_ulong handler;
199 
200     /* get target signal number */
201     sig = host_to_target_signal(host_signum);
202     if (sig < 1 || sig > TARGET_NSIG)
203         return;
204     k = &sigact_table[sig - 1];
205 #ifdef DEBUG_SIGNAL
206     fprintf(stderr, "gemu: got signal %d\n", sig);
207 #endif
208     handler = k->sa._sa_handler;
209     if (handler == TARGET_SIG_DFL) {
210         /* default handler : ignore some signal. The other are fatal */
211         if (sig != TARGET_SIGCHLD &&
212             sig != TARGET_SIGURG &&
213             sig != TARGET_SIGWINCH) {
214             force_sig(sig);
215         }
216     } else if (handler == TARGET_SIG_IGN) {
217         /* ignore signal */
218     } else if (handler == TARGET_SIG_ERR) {
219         force_sig(sig);
220     } else {
221         queue_signal(k, sig, info);
222     }
223 }
224 
225 int do_sigaction(int sig, const struct target_sigaction *act,
226                  struct target_sigaction *oact)
227 {
228     struct emulated_sigaction *k;
229 
230     if (sig < 1 || sig > TARGET_NSIG)
231         return -EINVAL;
232     k = &sigact_table[sig - 1];
233 #if defined(DEBUG_SIGNAL) && 0
234     fprintf(stderr, "sigaction sig=%d act=0x%08x, oact=0x%08x\n",
235             sig, (int)act, (int)oact);
236 #endif
237     if (oact) {
238         oact->_sa_handler = tswapl(k->sa._sa_handler);
239         oact->sa_flags = tswapl(k->sa.sa_flags);
240         oact->sa_restorer = tswapl(k->sa.sa_restorer);
241         oact->sa_mask = k->sa.sa_mask;
242     }
243     if (act) {
244         k->sa._sa_handler = tswapl(act->_sa_handler);
245         k->sa.sa_flags = tswapl(act->sa_flags);
246         k->sa.sa_restorer = tswapl(act->sa_restorer);
247         k->sa.sa_mask = act->sa_mask;
248     }
249     return 0;
250 }
251 
252 #ifdef TARGET_I386
253 
254 /* from the Linux kernel */
255 
256 struct target_fpreg {
257 	uint16_t significand[4];
258 	uint16_t exponent;
259 };
260 
261 struct target_fpxreg {
262 	uint16_t significand[4];
263 	uint16_t exponent;
264 	uint16_t padding[3];
265 };
266 
267 struct target_xmmreg {
268 	target_ulong element[4];
269 };
270 
271 struct target_fpstate {
272 	/* Regular FPU environment */
273 	target_ulong 	cw;
274 	target_ulong	sw;
275 	target_ulong	tag;
276 	target_ulong	ipoff;
277 	target_ulong	cssel;
278 	target_ulong	dataoff;
279 	target_ulong	datasel;
280 	struct target_fpreg	_st[8];
281 	uint16_t	status;
282 	uint16_t	magic;		/* 0xffff = regular FPU data only */
283 
284 	/* FXSR FPU environment */
285 	target_ulong	_fxsr_env[6];	/* FXSR FPU env is ignored */
286 	target_ulong	mxcsr;
287 	target_ulong	reserved;
288 	struct target_fpxreg	_fxsr_st[8];	/* FXSR FPU reg data is ignored */
289 	struct target_xmmreg	_xmm[8];
290 	target_ulong	padding[56];
291 };
292 
293 #define X86_FXSR_MAGIC		0x0000
294 
295 struct target_sigcontext {
296 	uint16_t gs, __gsh;
297 	uint16_t fs, __fsh;
298 	uint16_t es, __esh;
299 	uint16_t ds, __dsh;
300 	target_ulong edi;
301 	target_ulong esi;
302 	target_ulong ebp;
303 	target_ulong esp;
304 	target_ulong ebx;
305 	target_ulong edx;
306 	target_ulong ecx;
307 	target_ulong eax;
308 	target_ulong trapno;
309 	target_ulong err;
310 	target_ulong eip;
311 	uint16_t cs, __csh;
312 	target_ulong eflags;
313 	target_ulong esp_at_signal;
314 	uint16_t ss, __ssh;
315         target_ulong fpstate; /* pointer */
316 	target_ulong oldmask;
317 	target_ulong cr2;
318 };
319 
320 typedef struct target_sigaltstack {
321 	target_ulong ss_sp;
322 	int ss_flags;
323 	target_ulong ss_size;
324 } target_stack_t;
325 
326 struct target_ucontext {
327         target_ulong	  uc_flags;
328 	target_ulong      uc_link;
329 	target_stack_t	  uc_stack;
330 	struct target_sigcontext uc_mcontext;
331 	target_sigset_t	  uc_sigmask;	/* mask last for extensibility */
332 };
333 
334 struct sigframe
335 {
336     target_ulong pretcode;
337     int sig;
338     struct target_sigcontext sc;
339     struct target_fpstate fpstate;
340     target_ulong extramask[TARGET_NSIG_WORDS-1];
341     char retcode[8];
342 };
343 
344 struct rt_sigframe
345 {
346     target_ulong pretcode;
347     int sig;
348     target_ulong pinfo;
349     target_ulong puc;
350     struct target_siginfo info;
351     struct target_ucontext uc;
352     struct target_fpstate fpstate;
353     char retcode[8];
354 };
355 
356 /*
357  * Set up a signal frame.
358  */
359 
360 #define __put_user(x,ptr)\
361 ({\
362     int size = sizeof(*ptr);\
363     switch(size) {\
364     case 1:\
365         stb(ptr, (typeof(*ptr))(x));\
366         break;\
367     case 2:\
368         stw(ptr, (typeof(*ptr))(x));\
369         break;\
370     case 4:\
371         stl(ptr, (typeof(*ptr))(x));\
372         break;\
373     case 8:\
374         stq(ptr, (typeof(*ptr))(x));\
375         break;\
376     default:\
377         abort();\
378     }\
379     0;\
380 })
381 
382 #define get_user(val, ptr) (typeof(*ptr))(*(ptr))
383 
384 
385 #define __copy_to_user(dst, src, size)\
386 ({\
387     memcpy(dst, src, size);\
388     0;\
389 })
390 
391 static inline int copy_siginfo_to_user(target_siginfo_t *tinfo, siginfo_t *info)
392 {
393     host_to_target_siginfo(tinfo, info);
394     return 0;
395 }
396 
397 /* XXX: save x87 state */
398 static int
399 setup_sigcontext(struct target_sigcontext *sc, struct target_fpstate *fpstate,
400 		 CPUX86State *env, unsigned long mask)
401 {
402 	int err = 0;
403 
404 	err |= __put_user(env->segs[R_GS], (unsigned int *)&sc->gs);
405 	err |= __put_user(env->segs[R_FS], (unsigned int *)&sc->fs);
406 	err |= __put_user(env->segs[R_ES], (unsigned int *)&sc->es);
407 	err |= __put_user(env->segs[R_DS], (unsigned int *)&sc->ds);
408 	err |= __put_user(env->regs[R_EDI], &sc->edi);
409 	err |= __put_user(env->regs[R_ESI], &sc->esi);
410 	err |= __put_user(env->regs[R_EBP], &sc->ebp);
411 	err |= __put_user(env->regs[R_ESP], &sc->esp);
412 	err |= __put_user(env->regs[R_EBX], &sc->ebx);
413 	err |= __put_user(env->regs[R_EDX], &sc->edx);
414 	err |= __put_user(env->regs[R_ECX], &sc->ecx);
415 	err |= __put_user(env->regs[R_EAX], &sc->eax);
416 	err |= __put_user(/*current->thread.trap_no*/ 0, &sc->trapno);
417 	err |= __put_user(/*current->thread.error_code*/ 0, &sc->err);
418 	err |= __put_user(env->eip, &sc->eip);
419 	err |= __put_user(env->segs[R_CS], (unsigned int *)&sc->cs);
420 	err |= __put_user(env->eflags, &sc->eflags);
421 	err |= __put_user(env->regs[R_ESP], &sc->esp_at_signal);
422 	err |= __put_user(env->segs[R_SS], (unsigned int *)&sc->ss);
423 #if 0
424 	tmp = save_i387(fpstate);
425 	if (tmp < 0)
426 	  err = 1;
427 	else
428 	  err |= __put_user(tmp ? fpstate : NULL, &sc->fpstate);
429 #else
430         err |= __put_user(0, &sc->fpstate);
431 #endif
432 	/* non-iBCS2 extensions.. */
433 	err |= __put_user(mask, &sc->oldmask);
434 	err |= __put_user(/*current->thread.cr2*/ 0, &sc->cr2);
435 
436 	return err;
437 }
438 
439 /*
440  * Determine which stack to use..
441  */
442 
443 static inline void *
444 get_sigframe(struct emulated_sigaction *ka, CPUX86State *env, size_t frame_size)
445 {
446 	unsigned long esp;
447 
448 	/* Default to using normal stack */
449 	esp = env->regs[R_ESP];
450 #if 0
451 	/* This is the X/Open sanctioned signal stack switching.  */
452 	if (ka->sa.sa_flags & SA_ONSTACK) {
453 		if (sas_ss_flags(esp) == 0)
454 			esp = current->sas_ss_sp + current->sas_ss_size;
455 	}
456 
457 	/* This is the legacy signal stack switching. */
458 	else if ((regs->xss & 0xffff) != __USER_DS &&
459 		 !(ka->sa.sa_flags & SA_RESTORER) &&
460 		 ka->sa.sa_restorer) {
461 		esp = (unsigned long) ka->sa.sa_restorer;
462 	}
463 #endif
464 	return (void *)((esp - frame_size) & -8ul);
465 }
466 
467 #define TF_MASK TRAP_FLAG
468 
469 static void setup_frame(int sig, struct emulated_sigaction *ka,
470 			target_sigset_t *set, CPUX86State *env)
471 {
472 	struct sigframe *frame;
473 	int err = 0;
474 
475 	frame = get_sigframe(ka, env, sizeof(*frame));
476 
477 #if 0
478 	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
479 		goto give_sigsegv;
480 #endif
481 	err |= __put_user((/*current->exec_domain
482 		           && current->exec_domain->signal_invmap
483 		           && sig < 32
484 		           ? current->exec_domain->signal_invmap[sig]
485 		           : */ sig),
486 		          &frame->sig);
487 	if (err)
488 		goto give_sigsegv;
489 
490 	setup_sigcontext(&frame->sc, &frame->fpstate, env, set->sig[0]);
491 	if (err)
492 		goto give_sigsegv;
493 
494 	if (TARGET_NSIG_WORDS > 1) {
495 		err |= __copy_to_user(frame->extramask, &set->sig[1],
496 				      sizeof(frame->extramask));
497 	}
498 	if (err)
499 		goto give_sigsegv;
500 
501 	/* Set up to return from userspace.  If provided, use a stub
502 	   already in userspace.  */
503 	if (ka->sa.sa_flags & TARGET_SA_RESTORER) {
504 		err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
505 	} else {
506 		err |= __put_user(frame->retcode, &frame->pretcode);
507 		/* This is popl %eax ; movl $,%eax ; int $0x80 */
508 		err |= __put_user(0xb858, (short *)(frame->retcode+0));
509 		err |= __put_user(TARGET_NR_sigreturn, (int *)(frame->retcode+2));
510 		err |= __put_user(0x80cd, (short *)(frame->retcode+6));
511 	}
512 
513 	if (err)
514 		goto give_sigsegv;
515 
516 	/* Set up registers for signal handler */
517 	env->regs[R_ESP] = (unsigned long) frame;
518 	env->eip = (unsigned long) ka->sa._sa_handler;
519 
520         cpu_x86_load_seg(env, R_DS, __USER_DS);
521         cpu_x86_load_seg(env, R_ES, __USER_DS);
522         cpu_x86_load_seg(env, R_SS, __USER_DS);
523         cpu_x86_load_seg(env, R_CS, __USER_CS);
524 	env->eflags &= ~TF_MASK;
525 
526 	return;
527 
528 give_sigsegv:
529 	if (sig == TARGET_SIGSEGV)
530 		ka->sa._sa_handler = TARGET_SIG_DFL;
531 	force_sig(TARGET_SIGSEGV /* , current */);
532 }
533 
534 static void setup_rt_frame(int sig, struct emulated_sigaction *ka, siginfo_t *info,
535 			   target_sigset_t *set, CPUX86State *env)
536 {
537 	struct rt_sigframe *frame;
538 	int err = 0;
539 
540 	frame = get_sigframe(ka, env, sizeof(*frame));
541 
542 #if 0
543 	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
544 		goto give_sigsegv;
545 #endif
546 
547 	err |= __put_user((/*current->exec_domain
548 		    	   && current->exec_domain->signal_invmap
549 		    	   && sig < 32
550 		    	   ? current->exec_domain->signal_invmap[sig]
551 			   : */sig),
552 			  &frame->sig);
553 	err |= __put_user((target_ulong)&frame->info, &frame->pinfo);
554 	err |= __put_user((target_ulong)&frame->uc, &frame->puc);
555 	err |= copy_siginfo_to_user(&frame->info, info);
556 	if (err)
557 		goto give_sigsegv;
558 
559 	/* Create the ucontext.  */
560 	err |= __put_user(0, &frame->uc.uc_flags);
561 	err |= __put_user(0, &frame->uc.uc_link);
562 	err |= __put_user(/*current->sas_ss_sp*/ 0, &frame->uc.uc_stack.ss_sp);
563 	err |= __put_user(/* sas_ss_flags(regs->esp) */ 0,
564 			  &frame->uc.uc_stack.ss_flags);
565 	err |= __put_user(/* current->sas_ss_size */ 0, &frame->uc.uc_stack.ss_size);
566 	err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->fpstate,
567 			        env, set->sig[0]);
568 	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
569 	if (err)
570 		goto give_sigsegv;
571 
572 	/* Set up to return from userspace.  If provided, use a stub
573 	   already in userspace.  */
574 	if (ka->sa.sa_flags & TARGET_SA_RESTORER) {
575 		err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
576 	} else {
577 		err |= __put_user(frame->retcode, &frame->pretcode);
578 		/* This is movl $,%eax ; int $0x80 */
579 		err |= __put_user(0xb8, (char *)(frame->retcode+0));
580 		err |= __put_user(TARGET_NR_rt_sigreturn, (int *)(frame->retcode+1));
581 		err |= __put_user(0x80cd, (short *)(frame->retcode+5));
582 	}
583 
584 	if (err)
585 		goto give_sigsegv;
586 
587 	/* Set up registers for signal handler */
588 	env->regs[R_ESP] = (unsigned long) frame;
589 	env->eip = (unsigned long) ka->sa._sa_handler;
590 
591         cpu_x86_load_seg(env, R_DS, __USER_DS);
592         cpu_x86_load_seg(env, R_ES, __USER_DS);
593         cpu_x86_load_seg(env, R_SS, __USER_DS);
594         cpu_x86_load_seg(env, R_CS, __USER_CS);
595 	env->eflags &= ~TF_MASK;
596 
597 	return;
598 
599 give_sigsegv:
600 	if (sig == TARGET_SIGSEGV)
601 		ka->sa._sa_handler = TARGET_SIG_DFL;
602 	force_sig(TARGET_SIGSEGV /* , current */);
603 }
604 
605 static int
606 restore_sigcontext(CPUX86State *env, struct target_sigcontext *sc, int *peax)
607 {
608 	unsigned int err = 0;
609 
610 
611 
612 #define COPY(x)		err |= __get_user(regs->x, &sc->x)
613 
614 #define COPY_SEG(seg)							\
615 	{ unsigned short tmp;						\
616 	  err |= __get_user(tmp, &sc->seg);				\
617 	  regs->x##seg = tmp; }
618 
619 #define COPY_SEG_STRICT(seg)						\
620 	{ unsigned short tmp;						\
621 	  err |= __get_user(tmp, &sc->seg);				\
622 	  regs->x##seg = tmp|3; }
623 
624 #define GET_SEG(seg)							\
625 	{ unsigned short tmp;						\
626 	  err |= __get_user(tmp, &sc->seg);				\
627 	  loadsegment(seg,tmp); }
628 
629         cpu_x86_load_seg(env, R_GS, lduw(&sc->gs));
630         cpu_x86_load_seg(env, R_FS, lduw(&sc->fs));
631         cpu_x86_load_seg(env, R_ES, lduw(&sc->es));
632         cpu_x86_load_seg(env, R_DS, lduw(&sc->ds));
633 
634         env->regs[R_EDI] = ldl(&sc->edi);
635         env->regs[R_ESI] = ldl(&sc->esi);
636         env->regs[R_EBP] = ldl(&sc->ebp);
637         env->regs[R_ESP] = ldl(&sc->esp);
638         env->regs[R_EBX] = ldl(&sc->ebx);
639         env->regs[R_EDX] = ldl(&sc->edx);
640         env->regs[R_ECX] = ldl(&sc->ecx);
641         env->eip = ldl(&sc->eip);
642 
643         cpu_x86_load_seg(env, R_CS, lduw(&sc->cs) | 3);
644         cpu_x86_load_seg(env, R_SS, lduw(&sc->ss) | 3);
645 
646 	{
647 		unsigned int tmpflags;
648                 tmpflags = ldl(&sc->eflags);
649 		env->eflags = (env->eflags & ~0x40DD5) | (tmpflags & 0x40DD5);
650                 //		regs->orig_eax = -1;		/* disable syscall checks */
651 	}
652 
653 #if 0
654 	{
655 		struct _fpstate * buf;
656 		err |= __get_user(buf, &sc->fpstate);
657 		if (buf) {
658 			if (verify_area(VERIFY_READ, buf, sizeof(*buf)))
659 				goto badframe;
660 			err |= restore_i387(buf);
661 		}
662 	}
663 #endif
664         *peax = ldl(&sc->eax);
665 	return err;
666 #if 0
667 badframe:
668 	return 1;
669 #endif
670 }
671 
672 long do_sigreturn(CPUX86State *env)
673 {
674     struct sigframe *frame = (struct sigframe *)(env->regs[R_ESP] - 8);
675     target_sigset_t target_set;
676     sigset_t set;
677     int eax, i;
678 
679     /* set blocked signals */
680     target_set.sig[0] = frame->sc.oldmask;
681     for(i = 1; i < TARGET_NSIG_WORDS; i++)
682         target_set.sig[i] = frame->extramask[i - 1];
683 
684     target_to_host_sigset(&set, &target_set);
685     sigprocmask(SIG_SETMASK, &set, NULL);
686 
687     /* restore registers */
688     if (restore_sigcontext(env, &frame->sc, &eax))
689         goto badframe;
690     return eax;
691 
692 badframe:
693     force_sig(TARGET_SIGSEGV);
694     return 0;
695 }
696 
697 long do_rt_sigreturn(CPUX86State *env)
698 {
699 	struct rt_sigframe *frame = (struct rt_sigframe *)(env->regs[R_ESP] - 4);
700 	target_sigset_t target_set;
701         sigset_t set;
702         //	stack_t st;
703 	int eax;
704 
705 #if 0
706 	if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
707 		goto badframe;
708 #endif
709         memcpy(&target_set, &frame->uc.uc_sigmask, sizeof(target_sigset_t));
710 
711         target_to_host_sigset(&set, &target_set);
712         sigprocmask(SIG_SETMASK, &set, NULL);
713 
714 	if (restore_sigcontext(env, &frame->uc.uc_mcontext, &eax))
715 		goto badframe;
716 
717 #if 0
718 	if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st)))
719 		goto badframe;
720 	/* It is more difficult to avoid calling this function than to
721 	   call it and ignore errors.  */
722 	do_sigaltstack(&st, NULL, regs->esp);
723 #endif
724 	return eax;
725 
726 badframe:
727 	force_sig(TARGET_SIGSEGV);
728 	return 0;
729 }
730 
731 #endif
732 
733 void process_pending_signals(void *cpu_env)
734 {
735     int sig;
736     target_ulong handler;
737     target_sigset_t set;
738     struct emulated_sigaction *k;
739     struct sigqueue *q;
740 
741     if (!signal_pending)
742         return;
743 
744     k = sigact_table;
745     for(sig = 1; sig <= TARGET_NSIG; sig++) {
746         if (k->pending)
747             goto handle_signal;
748         k++;
749     }
750     /* if no signal is pending, just return */
751     signal_pending = 0;
752     return;
753 
754  handle_signal:
755 #ifdef DEBUG_SIGNAL
756     fprintf(stderr, "gemu: process signal %d\n", sig);
757 #endif
758     /* dequeue signal */
759     q = k->first;
760     k->first = q->next;
761     if (!k->first)
762         k->pending = 0;
763 
764     handler = k->sa._sa_handler;
765     if (handler == TARGET_SIG_DFL) {
766         /* default handler : ignore some signal. The other are fatal */
767         if (sig != TARGET_SIGCHLD &&
768             sig != TARGET_SIGURG &&
769             sig != TARGET_SIGWINCH) {
770             force_sig(sig);
771         }
772     } else if (handler == TARGET_SIG_IGN) {
773         /* ignore sig */
774     } else if (handler == TARGET_SIG_ERR) {
775         force_sig(sig);
776     } else {
777         set = k->sa.sa_mask;
778         /* send the signal to the CPU */
779         if (k->sa.sa_flags & TARGET_SA_SIGINFO)
780             setup_rt_frame(sig, k, &q->info, &set, cpu_env);
781         else
782             setup_frame(sig, k, &set, cpu_env);
783 	if (k->sa.sa_flags & TARGET_SA_RESETHAND)
784             k->sa._sa_handler = TARGET_SIG_DFL;
785     }
786     if (q != &k->info)
787         free_sigqueue(q);
788 }
789 
790 
791