darwin-user/signal.c - qemu - Git at Google

 /*
  *  Emulation of Linux signals
  *
  *  Copyright (c) 2003 Fabrice Bellard
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License, or
  *  (at your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdarg.h>
 #include <unistd.h>
 #include <signal.h>
 #include <errno.h>
 #include <sys/ucontext.h>

 #ifdef __ia64__
 #undef uc_mcontext
 #undef uc_sigmask
 #undef uc_stack
 #undef uc_link
 #endif

 #include <signal.h>

 #include "qemu.h"

 #define DEBUG_SIGNAL

 #define MAX_SIGQUEUE_SIZE 1024

 struct sigqueue {
     struct sigqueue *next;
     target_siginfo_t info;
 };

 struct emulated_sigaction {
     struct target_sigaction sa;
     int pending; /* true if signal is pending */
     struct sigqueue *first;
     struct sigqueue info; /* in order to always have memory for the
                              first signal, we put it here */
 };

 static struct sigaltstack target_sigaltstack_used = {
     0, 0, SA_DISABLE
 };

 static struct emulated_sigaction sigact_table[NSIG];
 static struct sigqueue sigqueue_table[MAX_SIGQUEUE_SIZE]; /* siginfo queue */
 static struct sigqueue *first_free; /* first free siginfo queue entry */
 static int signal_pending; /* non zero if a signal may be pending */

 static void host_signal_handler(int host_signum, siginfo_t *info,
                                 void *puc);


 static inline int host_to_target_signal(int sig)
 {
     return sig;
 }

 static inline int target_to_host_signal(int sig)
 {
     return sig;
 }

 /* siginfo conversion */


 void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info)
 {

 }

 void target_to_host_siginfo(siginfo_t *info, const target_siginfo_t *tinfo)
 {

 }

 void signal_init(void)
 {
     struct sigaction act;
     int i;

     /* set all host signal handlers. ALL signals are blocked during
        the handlers to serialize them. */
     sigfillset(&act.sa_mask);
     act.sa_flags = SA_SIGINFO;
     act.sa_sigaction = host_signal_handler;
     for(i = 1; i < NSIG; i++) {
         sigaction(i, &act, NULL);
     }

     memset(sigact_table, 0, sizeof(sigact_table));

     first_free = &sigqueue_table[0];
     for(i = 0; i < MAX_SIGQUEUE_SIZE - 1; i++)
         sigqueue_table[i].next = &sigqueue_table[i + 1];
     sigqueue_table[MAX_SIGQUEUE_SIZE - 1].next = NULL;
 }

 /* signal queue handling */

 static inline struct sigqueue *alloc_sigqueue(void)
 {
     struct sigqueue *q = first_free;
     if (!q)
         return NULL;
     first_free = q->next;
     return q;
 }

 static inline void free_sigqueue(struct sigqueue *q)
 {
     q->next = first_free;
     first_free = q;
 }

 /* abort execution with signal */
 void __attribute((noreturn)) force_sig(int sig)
 {
     int host_sig;
     host_sig = target_to_host_signal(sig);
     fprintf(stderr, "qemu: uncaught target signal %d (%s) - exiting\n",
             sig, strsignal(host_sig));
     _exit(-host_sig);
 }

 /* queue a signal so that it will be send to the virtual CPU as soon
    as possible */
 int queue_signal(int sig, target_siginfo_t *info)
 {
     struct emulated_sigaction *k;
     struct sigqueue *q, **pq;
     target_ulong handler;

 #if defined(DEBUG_SIGNAL)
     fprintf(stderr, "queue_signal: sig=%d\n",
             sig);
 #endif
     k = &sigact_table[sig - 1];
     handler = (target_ulong)k->sa.sa_handler;
     if (handler == SIG_DFL) {
         /* default handler : ignore some signal. The other are fatal */
         if (sig != SIGCHLD &&
             sig != SIGURG &&
             sig != SIGWINCH) {
             force_sig(sig);
         } else {
             return 0; /* indicate ignored */
         }
     } else if (handler == host_to_target_signal(SIG_IGN)) {
         /* ignore signal */
         return 0;
     } else if (handler == host_to_target_signal(SIG_ERR)) {
         force_sig(sig);
     } else {
         pq = &k->first;
         if (!k->pending) {
             /* first signal */
             q = &k->info;
         } else {
             q = alloc_sigqueue();
             if (!q)
                 return -EAGAIN;
             while (*pq != NULL)
                 pq = &(*pq)->next;
         }
         *pq = q;
         q->info = *info;
         q->next = NULL;
         k->pending = 1;
         /* signal that a new signal is pending */
         signal_pending = 1;
         return 1; /* indicates that the signal was queued */
     }
 }

 static void host_signal_handler(int host_signum, siginfo_t *info,
                                 void *puc)
 {
     int sig;
     target_siginfo_t tinfo;

     /* the CPU emulator uses some host signals to detect exceptions,
        we we forward to it some signals */
     if (host_signum == SIGSEGV || host_signum == SIGBUS) {
         if (cpu_signal_handler(host_signum, (void*)info, puc))
             return;
     }

     /* get target signal number */
     sig = host_to_target_signal(host_signum);
     if (sig < 1 || sig > NSIG)
         return;

 #if defined(DEBUG_SIGNAL)
 	fprintf(stderr, "qemu: got signal %d\n", sig);
 #endif
     if (queue_signal(sig, &tinfo) == 1) {
         /* interrupt the virtual CPU as soon as possible */
         cpu_interrupt(global_env, CPU_INTERRUPT_EXIT);
     }
 }

 int do_sigaltstack(const struct sigaltstack *ss, struct sigaltstack *oss)
 {
     /* XXX: test errors */
     if(oss)
     {
         oss->ss_sp = tswap32(target_sigaltstack_used.ss_sp);
         oss->ss_size = tswap32(target_sigaltstack_used.ss_size);
         oss->ss_flags = tswap32(target_sigaltstack_used.ss_flags);
     }
     if(ss)
     {
         target_sigaltstack_used.ss_sp = tswap32(ss->ss_sp);
         target_sigaltstack_used.ss_size = tswap32(ss->ss_size);
         target_sigaltstack_used.ss_flags = tswap32(ss->ss_flags);
     }
     return 0;
 }

 int do_sigaction(int sig, const struct sigaction *act,
                  struct sigaction *oact)
 {
     struct emulated_sigaction *k;
     struct sigaction act1;
     int host_sig;

     if (sig < 1 || sig > NSIG)
         return -EINVAL;

     k = &sigact_table[sig - 1];
 #if defined(DEBUG_SIGNAL)
     fprintf(stderr, "sigaction 1 sig=%d act=0x%08x, oact=0x%08x\n",
             sig, (int)act, (int)oact);
 #endif
     if (oact) {
 #if defined(DEBUG_SIGNAL)
     fprintf(stderr, "sigaction 1 sig=%d act=0x%08x, oact=0x%08x\n",
             sig, (int)act, (int)oact);
 #endif

         oact->sa_handler = tswapl(k->sa.sa_handler);
         oact->sa_flags = tswapl(k->sa.sa_flags);
         oact->sa_mask = tswapl(k->sa.sa_mask);
     }
     if (act) {
 #if defined(DEBUG_SIGNAL)
     fprintf(stderr, "sigaction handler 0x%x flag 0x%x mask 0x%x\n",
             act->sa_handler, act->sa_flags, act->sa_mask);
 #endif

         k->sa.sa_handler = tswapl(act->sa_handler);
         k->sa.sa_flags = tswapl(act->sa_flags);
         k->sa.sa_mask = tswapl(act->sa_mask);
         /* we update the host signal state */
         host_sig = target_to_host_signal(sig);
         if (host_sig != SIGSEGV && host_sig != SIGBUS) {
 #if defined(DEBUG_SIGNAL)
     fprintf(stderr, "sigaction handler going to call sigaction\n",
             act->sa_handler, act->sa_flags, act->sa_mask);
 #endif

             sigfillset(&act1.sa_mask);
             act1.sa_flags = SA_SIGINFO;
             if (k->sa.sa_flags & SA_RESTART)
                 act1.sa_flags |= SA_RESTART;
             /* NOTE: it is important to update the host kernel signal
                ignore state to avoid getting unexpected interrupted
                syscalls */
             if (k->sa.sa_handler == SIG_IGN) {
                 act1.sa_sigaction = (void *)SIG_IGN;
             } else if (k->sa.sa_handler == SIG_DFL) {
                 act1.sa_sigaction = (void *)SIG_DFL;
             } else {
                 act1.sa_sigaction = host_signal_handler;
             }
             sigaction(host_sig, &act1, NULL);
         }
     }
     return 0;
 }


 #ifdef TARGET_I386

 static inline void *
 get_sigframe(struct emulated_sigaction *ka, CPUX86State *env, size_t frame_size)
 {
     /* XXX Fix that */
     if(target_sigaltstack_used.ss_flags & SA_DISABLE)
     {
         int esp;
         /* Default to using normal stack */
         esp = env->regs[R_ESP];

         return (void *)((esp - frame_size) & -8ul);
     }
     else
     {
         return target_sigaltstack_used.ss_sp;
     }
 }

 static void setup_frame(int sig, struct emulated_sigaction *ka,
 			void *set, CPUState *env)
 {
 	void *frame;
 	int i, err = 0;

     fprintf(stderr, "setup_frame %d\n", sig);
 	frame = get_sigframe(ka, env, sizeof(*frame));

 	/* Set up registers for signal handler */
 	env->regs[R_ESP] = (unsigned long) frame;
 	env->eip = (unsigned long) ka->sa.sa_handler;

 	env->eflags &= ~TF_MASK;

 	return;

 give_sigsegv:
 	if (sig == SIGSEGV)
 		ka->sa.sa_handler = SIG_DFL;
 	force_sig(SIGSEGV /* , current */);
 }

 long do_sigreturn(CPUState *env, int num)
 {
     int i = 0;
     struct target_sigcontext *scp = get_int_arg(&i, env);
     /* XXX Get current signal number */
     /* XXX Adjust accordin to sc_onstack, sc_mask */
     if(tswapl(scp->sc_onstack) & 0x1)
         target_sigaltstack_used.ss_flags |= ~SA_DISABLE;
     else
         target_sigaltstack_used.ss_flags &=  SA_DISABLE;
     int set = tswapl(scp->sc_eax);
     sigprocmask(SIG_SETMASK, &set, NULL);

     fprintf(stderr, "do_sigreturn: partially implemented %x EAX:%x EBX:%x\n", scp->sc_mask, tswapl(scp->sc_eax), tswapl(scp->sc_ebx));
     fprintf(stderr, "ECX:%x EDX:%x EDI:%x\n", scp->sc_ecx, tswapl(scp->sc_edx), tswapl(scp->sc_edi));
     fprintf(stderr, "EIP:%x\n", tswapl(scp->sc_eip));

     env->regs[R_EAX] = tswapl(scp->sc_eax);
     env->regs[R_EBX] = tswapl(scp->sc_ebx);
     env->regs[R_ECX] = tswapl(scp->sc_ecx);
     env->regs[R_EDX] = tswapl(scp->sc_edx);
     env->regs[R_EDI] = tswapl(scp->sc_edi);
     env->regs[R_ESI] = tswapl(scp->sc_esi);
     env->regs[R_EBP] = tswapl(scp->sc_ebp);
     env->regs[R_ESP] = tswapl(scp->sc_esp);
     env->segs[R_SS].selector = (void*)tswapl(scp->sc_ss);
     env->eflags = tswapl(scp->sc_eflags);
     env->eip = tswapl(scp->sc_eip);
     env->segs[R_CS].selector = (void*)tswapl(scp->sc_cs);
     env->segs[R_DS].selector = (void*)tswapl(scp->sc_ds);
     env->segs[R_ES].selector = (void*)tswapl(scp->sc_es);
     env->segs[R_FS].selector = (void*)tswapl(scp->sc_fs);
     env->segs[R_GS].selector = (void*)tswapl(scp->sc_gs);

     /* Again, because our caller's caller will reset EAX */
     return env->regs[R_EAX];
 }

 #else

 static void setup_frame(int sig, struct emulated_sigaction *ka,
 			void *set, CPUState *env)
 {
     fprintf(stderr, "setup_frame: not implemented\n");
 }

 long do_sigreturn(CPUState *env, int num)
 {
     int i = 0;
     struct target_sigcontext *scp = get_int_arg(&i, env);
     fprintf(stderr, "do_sigreturn: not implemented\n");
     return -ENOSYS;
 }

 #endif

 void process_pending_signals(void *cpu_env)
 {
     struct emulated_sigaction *k;
     struct sigqueue *q;
     target_ulong handler;
     int sig;

     if (!signal_pending)
         return;

     k = sigact_table;

     for(sig = 1; sig <= NSIG; sig++) {
         if (k->pending)
             goto handle_signal;
         k++;
     }

     /* if no signal is pending, just return */
     signal_pending = 0;
     return;
 handle_signal:
     #ifdef DEBUG_SIGNAL
     fprintf(stderr, "qemu: process signal %d\n", sig);
     #endif
     /* dequeue signal */
     q = k->first;
     k->first = q->next;
     if (!k->first)
         k->pending = 0;

     sig = gdb_handlesig (cpu_env, sig);
     if (!sig) {
         fprintf (stderr, "Lost signal\n");
         abort();
     }

     handler = k->sa.sa_handler;
     if (handler == SIG_DFL) {
         /* default handler : ignore some signal. The other are fatal */
         if (sig != SIGCHLD &&
             sig != SIGURG &&
             sig != SIGWINCH) {
             force_sig(sig);
         }
     } else if (handler == SIG_IGN) {
         /* ignore sig */
     } else if (handler == SIG_ERR) {
         force_sig(sig);
     } else {

         setup_frame(sig, k, 0, cpu_env);
 	if (k->sa.sa_flags & SA_RESETHAND)
             k->sa.sa_handler = SIG_DFL;
     }
     if (q != &k->info)
         free_sigqueue(q);
 }
	/*
	* Emulation of Linux signals
	*
	* Copyright (c) 2003 Fabrice Bellard
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	*/
	#include <stdlib.h>
	#include <stdio.h>
	#include <string.h>
	#include <stdarg.h>
	#include <unistd.h>
	#include <signal.h>
	#include <errno.h>
	#include <sys/ucontext.h>

	#ifdef __ia64__
	#undef uc_mcontext
	#undef uc_sigmask
	#undef uc_stack
	#undef uc_link
	#endif

	#include <signal.h>

	#include "qemu.h"

	#define DEBUG_SIGNAL

	#define MAX_SIGQUEUE_SIZE 1024

	struct sigqueue {
	struct sigqueue *next;
	target_siginfo_t info;
	};

	struct emulated_sigaction {
	struct target_sigaction sa;
	int pending; /* true if signal is pending */
	struct sigqueue *first;
	struct sigqueue info; /* in order to always have memory for the
	first signal, we put it here */
	};

	static struct sigaltstack target_sigaltstack_used = {
	0, 0, SA_DISABLE
	};

	static struct emulated_sigaction sigact_table[NSIG];
	static struct sigqueue sigqueue_table[MAX_SIGQUEUE_SIZE]; /* siginfo queue */
	static struct sigqueue first_free; / first free siginfo queue entry */
	static int signal_pending; /* non zero if a signal may be pending */

	static void host_signal_handler(int host_signum, siginfo_t *info,
	void *puc);


	static inline int host_to_target_signal(int sig)
	{
	return sig;
	}

	static inline int target_to_host_signal(int sig)
	{
	return sig;
	}

	/* siginfo conversion */



	void host_to_target_siginfo(target_siginfo_t tinfo, const siginfo_t info)
	{

	}

	void target_to_host_siginfo(siginfo_t info, const target_siginfo_t tinfo)
	{

	}

	void signal_init(void)
	{
	struct sigaction act;
	int i;

	/* set all host signal handlers. ALL signals are blocked during
	the handlers to serialize them. */
	sigfillset(&act.sa_mask);
	act.sa_flags = SA_SIGINFO;
	act.sa_sigaction = host_signal_handler;
	for(i = 1; i < NSIG; i++) {
	sigaction(i, &act, NULL);
	}

	memset(sigact_table, 0, sizeof(sigact_table));

	first_free = &sigqueue_table[0];
	for(i = 0; i < MAX_SIGQUEUE_SIZE - 1; i++)
	sigqueue_table[i].next = &sigqueue_table[i + 1];
	sigqueue_table[MAX_SIGQUEUE_SIZE - 1].next = NULL;
	}

	/* signal queue handling */

	static inline struct sigqueue *alloc_sigqueue(void)
	{
	struct sigqueue *q = first_free;
	if (!q)
	return NULL;
	first_free = q->next;
	return q;
	}

	static inline void free_sigqueue(struct sigqueue *q)
	{
	q->next = first_free;
	first_free = q;
	}

	/* abort execution with signal */
	void __attribute((noreturn)) force_sig(int sig)
	{
	int host_sig;
	host_sig = target_to_host_signal(sig);
	fprintf(stderr, "qemu: uncaught target signal %d (%s) - exiting\n",
	sig, strsignal(host_sig));
	_exit(-host_sig);
	}

	/* queue a signal so that it will be send to the virtual CPU as soon
	as possible */
	int queue_signal(int sig, target_siginfo_t *info)
	{
	struct emulated_sigaction *k;
	struct sigqueue q, *pq;
	target_ulong handler;

	#if defined(DEBUG_SIGNAL)
	fprintf(stderr, "queue_signal: sig=%d\n",
	sig);
	#endif
	k = &sigact_table[sig - 1];
	handler = (target_ulong)k->sa.sa_handler;
	if (handler == SIG_DFL) {
	/* default handler : ignore some signal. The other are fatal */
	if (sig != SIGCHLD &&
	sig != SIGURG &&
	sig != SIGWINCH) {
	force_sig(sig);
	} else {
	return 0; /* indicate ignored */
	}
	} else if (handler == host_to_target_signal(SIG_IGN)) {
	/* ignore signal */
	return 0;
	} else if (handler == host_to_target_signal(SIG_ERR)) {
	force_sig(sig);
	} else {
	pq = &k->first;
	if (!k->pending) {
	/* first signal */
	q = &k->info;
	} else {
	q = alloc_sigqueue();
	if (!q)
	return -EAGAIN;
	while (*pq != NULL)
	pq = &(*pq)->next;
	}
	*pq = q;
	q->info = *info;
	q->next = NULL;
	k->pending = 1;
	/* signal that a new signal is pending */
	signal_pending = 1;
	return 1; /* indicates that the signal was queued */
	}
	}

	static void host_signal_handler(int host_signum, siginfo_t *info,
	void *puc)
	{
	int sig;
	target_siginfo_t tinfo;

	/* the CPU emulator uses some host signals to detect exceptions,
	we we forward to it some signals */
	if (host_signum == SIGSEGV \|\| host_signum == SIGBUS) {
	if (cpu_signal_handler(host_signum, (void*)info, puc))
	return;
	}

	/* get target signal number */
	sig = host_to_target_signal(host_signum);
	if (sig < 1 \|\| sig > NSIG)
	return;

	#if defined(DEBUG_SIGNAL)
	fprintf(stderr, "qemu: got signal %d\n", sig);
	#endif
	if (queue_signal(sig, &tinfo) == 1) {
	/* interrupt the virtual CPU as soon as possible */
	cpu_interrupt(global_env, CPU_INTERRUPT_EXIT);
	}
	}

	int do_sigaltstack(const struct sigaltstack ss, struct sigaltstack oss)
	{
	/* XXX: test errors */
	if(oss)
	{
	oss->ss_sp = tswap32(target_sigaltstack_used.ss_sp);
	oss->ss_size = tswap32(target_sigaltstack_used.ss_size);
	oss->ss_flags = tswap32(target_sigaltstack_used.ss_flags);
	}
	if(ss)
	{
	target_sigaltstack_used.ss_sp = tswap32(ss->ss_sp);
	target_sigaltstack_used.ss_size = tswap32(ss->ss_size);
	target_sigaltstack_used.ss_flags = tswap32(ss->ss_flags);
	}
	return 0;
	}

	int do_sigaction(int sig, const struct sigaction *act,
	struct sigaction *oact)
	{
	struct emulated_sigaction *k;
	struct sigaction act1;
	int host_sig;

	if (sig < 1 \|\| sig > NSIG)
	return -EINVAL;

	k = &sigact_table[sig - 1];
	#if defined(DEBUG_SIGNAL)
	fprintf(stderr, "sigaction 1 sig=%d act=0x%08x, oact=0x%08x\n",
	sig, (int)act, (int)oact);
	#endif
	if (oact) {
	#if defined(DEBUG_SIGNAL)
	fprintf(stderr, "sigaction 1 sig=%d act=0x%08x, oact=0x%08x\n",
	sig, (int)act, (int)oact);
	#endif

	oact->sa_handler = tswapl(k->sa.sa_handler);
	oact->sa_flags = tswapl(k->sa.sa_flags);
	oact->sa_mask = tswapl(k->sa.sa_mask);
	}
	if (act) {
	#if defined(DEBUG_SIGNAL)
	fprintf(stderr, "sigaction handler 0x%x flag 0x%x mask 0x%x\n",
	act->sa_handler, act->sa_flags, act->sa_mask);
	#endif

	k->sa.sa_handler = tswapl(act->sa_handler);
	k->sa.sa_flags = tswapl(act->sa_flags);
	k->sa.sa_mask = tswapl(act->sa_mask);
	/* we update the host signal state */
	host_sig = target_to_host_signal(sig);
	if (host_sig != SIGSEGV && host_sig != SIGBUS) {
	#if defined(DEBUG_SIGNAL)
	fprintf(stderr, "sigaction handler going to call sigaction\n",
	act->sa_handler, act->sa_flags, act->sa_mask);
	#endif

	sigfillset(&act1.sa_mask);
	act1.sa_flags = SA_SIGINFO;
	if (k->sa.sa_flags & SA_RESTART)
	act1.sa_flags \|= SA_RESTART;
	/* NOTE: it is important to update the host kernel signal
	ignore state to avoid getting unexpected interrupted
	syscalls */
	if (k->sa.sa_handler == SIG_IGN) {
	act1.sa_sigaction = (void *)SIG_IGN;
	} else if (k->sa.sa_handler == SIG_DFL) {
	act1.sa_sigaction = (void *)SIG_DFL;
	} else {
	act1.sa_sigaction = host_signal_handler;
	}
	sigaction(host_sig, &act1, NULL);
	}
	}
	return 0;
	}


	#ifdef TARGET_I386

	static inline void *
	get_sigframe(struct emulated_sigaction ka, CPUX86State env, size_t frame_size)
	{
	/* XXX Fix that */
	if(target_sigaltstack_used.ss_flags & SA_DISABLE)
	{
	int esp;
	/* Default to using normal stack */
	esp = env->regs[R_ESP];

	return (void *)((esp - frame_size) & -8ul);
	}
	else
	{
	return target_sigaltstack_used.ss_sp;
	}
	}

	static void setup_frame(int sig, struct emulated_sigaction *ka,
	void set, CPUState env)
	{
	void *frame;
	int i, err = 0;

	fprintf(stderr, "setup_frame %d\n", sig);
	frame = get_sigframe(ka, env, sizeof(*frame));

	/* Set up registers for signal handler */
	env->regs[R_ESP] = (unsigned long) frame;
	env->eip = (unsigned long) ka->sa.sa_handler;

	env->eflags &= ~TF_MASK;

	return;

	give_sigsegv:
	if (sig == SIGSEGV)
	ka->sa.sa_handler = SIG_DFL;
	force_sig(SIGSEGV /* , current */);
	}

	long do_sigreturn(CPUState *env, int num)
	{
	int i = 0;
	struct target_sigcontext *scp = get_int_arg(&i, env);
	/* XXX Get current signal number */
	/* XXX Adjust accordin to sc_onstack, sc_mask */
	if(tswapl(scp->sc_onstack) & 0x1)
	target_sigaltstack_used.ss_flags \|= ~SA_DISABLE;
	else
	target_sigaltstack_used.ss_flags &= SA_DISABLE;
	int set = tswapl(scp->sc_eax);
	sigprocmask(SIG_SETMASK, &set, NULL);

	fprintf(stderr, "do_sigreturn: partially implemented %x EAX:%x EBX:%x\n", scp->sc_mask, tswapl(scp->sc_eax), tswapl(scp->sc_ebx));
	fprintf(stderr, "ECX:%x EDX:%x EDI:%x\n", scp->sc_ecx, tswapl(scp->sc_edx), tswapl(scp->sc_edi));
	fprintf(stderr, "EIP:%x\n", tswapl(scp->sc_eip));

	env->regs[R_EAX] = tswapl(scp->sc_eax);
	env->regs[R_EBX] = tswapl(scp->sc_ebx);
	env->regs[R_ECX] = tswapl(scp->sc_ecx);
	env->regs[R_EDX] = tswapl(scp->sc_edx);
	env->regs[R_EDI] = tswapl(scp->sc_edi);
	env->regs[R_ESI] = tswapl(scp->sc_esi);
	env->regs[R_EBP] = tswapl(scp->sc_ebp);
	env->regs[R_ESP] = tswapl(scp->sc_esp);
	env->segs[R_SS].selector = (void*)tswapl(scp->sc_ss);
	env->eflags = tswapl(scp->sc_eflags);
	env->eip = tswapl(scp->sc_eip);
	env->segs[R_CS].selector = (void*)tswapl(scp->sc_cs);
	env->segs[R_DS].selector = (void*)tswapl(scp->sc_ds);
	env->segs[R_ES].selector = (void*)tswapl(scp->sc_es);
	env->segs[R_FS].selector = (void*)tswapl(scp->sc_fs);
	env->segs[R_GS].selector = (void*)tswapl(scp->sc_gs);

	/* Again, because our caller's caller will reset EAX */
	return env->regs[R_EAX];
	}

	#else

	static void setup_frame(int sig, struct emulated_sigaction *ka,
	void set, CPUState env)
	{
	fprintf(stderr, "setup_frame: not implemented\n");
	}

	long do_sigreturn(CPUState *env, int num)
	{
	int i = 0;
	struct target_sigcontext *scp = get_int_arg(&i, env);
	fprintf(stderr, "do_sigreturn: not implemented\n");
	return -ENOSYS;
	}

	#endif

	void process_pending_signals(void *cpu_env)
	{
	struct emulated_sigaction *k;
	struct sigqueue *q;
	target_ulong handler;
	int sig;

	if (!signal_pending)
	return;

	k = sigact_table;

	for(sig = 1; sig <= NSIG; sig++) {
	if (k->pending)
	goto handle_signal;
	k++;
	}

	/* if no signal is pending, just return */
	signal_pending = 0;
	return;
	handle_signal:
	#ifdef DEBUG_SIGNAL
	fprintf(stderr, "qemu: process signal %d\n", sig);
	#endif
	/* dequeue signal */
	q = k->first;
	k->first = q->next;
	if (!k->first)
	k->pending = 0;

	sig = gdb_handlesig (cpu_env, sig);
	if (!sig) {
	fprintf (stderr, "Lost signal\n");
	abort();
	}

	handler = k->sa.sa_handler;
	if (handler == SIG_DFL) {
	/* default handler : ignore some signal. The other are fatal */
	if (sig != SIGCHLD &&
	sig != SIGURG &&
	sig != SIGWINCH) {
	force_sig(sig);
	}
	} else if (handler == SIG_IGN) {
	/* ignore sig */
	} else if (handler == SIG_ERR) {
	force_sig(sig);
	} else {

	setup_frame(sig, k, 0, cpu_env);
	if (k->sa.sa_flags & SA_RESETHAND)
	k->sa.sa_handler = SIG_DFL;
	}
	if (q != &k->info)
	free_sigqueue(q);
	}