453 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			453 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			C
		
	
	
	
| /*
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|  *  Emulation of Linux signals
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|  *
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|  *  Copyright (c) 2003 Fabrice Bellard
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|  *
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|  *  This program is free software; you can redistribute it and/or modify
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|  *  it under the terms of the GNU General Public License as published by
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|  *  the Free Software Foundation; either version 2 of the License, or
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|  *  (at your option) any later version.
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|  *
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|  *  This program is distributed in the hope that it will be useful,
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|  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
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|  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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|  *  GNU General Public License for more details.
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|  *
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|  *  You should have received a copy of the GNU General Public License
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|  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
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|  */
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| #include <stdlib.h>
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| #include <stdio.h>
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| #include <string.h>
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| #include <stdarg.h>
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| #include <unistd.h>
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| #include <errno.h>
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| #include <sys/ucontext.h>
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| 
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| #ifdef __ia64__
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| #undef uc_mcontext
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| #undef uc_sigmask
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| #undef uc_stack
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| #undef uc_link
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| #endif
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| 
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| #include "qemu.h"
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| #include "qemu-common.h"
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| 
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| #define DEBUG_SIGNAL
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| 
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| #define MAX_SIGQUEUE_SIZE 1024
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| 
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| struct sigqueue {
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|     struct sigqueue *next;
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|     target_siginfo_t info;
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| };
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| 
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| struct emulated_sigaction {
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|     struct target_sigaction sa;
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|     int pending; /* true if signal is pending */
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|     struct sigqueue *first;
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|     struct sigqueue info; /* in order to always have memory for the
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|                              first signal, we put it here */
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| };
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| 
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| static struct sigaltstack target_sigaltstack_used = {
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|     0, 0, SA_DISABLE
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| };
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| 
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| static struct emulated_sigaction sigact_table[NSIG];
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| static struct sigqueue sigqueue_table[MAX_SIGQUEUE_SIZE]; /* siginfo queue */
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| static struct sigqueue *first_free; /* first free siginfo queue entry */
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| static int signal_pending; /* non zero if a signal may be pending */
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| 
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| static void host_signal_handler(int host_signum, siginfo_t *info,
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|                                 void *puc);
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| 
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| 
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| static inline int host_to_target_signal(int sig)
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| {
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|     return sig;
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| }
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| 
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| static inline int target_to_host_signal(int sig)
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| {
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|     return sig;
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| }
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| 
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| /* siginfo conversion */
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| 
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| 
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| 
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| void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info)
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| {
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| 
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| }
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| 
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| void target_to_host_siginfo(siginfo_t *info, const target_siginfo_t *tinfo)
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| {
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| 
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| }
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| 
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| void signal_init(void)
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| {
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|     struct sigaction act;
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|     int i;
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| 
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|     /* set all host signal handlers. ALL signals are blocked during
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|        the handlers to serialize them. */
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|     sigfillset(&act.sa_mask);
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|     act.sa_flags = SA_SIGINFO;
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|     act.sa_sigaction = host_signal_handler;
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|     for(i = 1; i < NSIG; i++) {
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|         sigaction(i, &act, NULL);
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|     }
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| 
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|     memset(sigact_table, 0, sizeof(sigact_table));
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| 
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|     first_free = &sigqueue_table[0];
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|     for(i = 0; i < MAX_SIGQUEUE_SIZE - 1; i++)
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|         sigqueue_table[i].next = &sigqueue_table[i + 1];
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|     sigqueue_table[MAX_SIGQUEUE_SIZE - 1].next = NULL;
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| }
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| 
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| /* signal queue handling */
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| 
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| static inline struct sigqueue *alloc_sigqueue(void)
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| {
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|     struct sigqueue *q = first_free;
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|     if (!q)
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|         return NULL;
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|     first_free = q->next;
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|     return q;
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| }
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| 
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| static inline void free_sigqueue(struct sigqueue *q)
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| {
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|     q->next = first_free;
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|     first_free = q;
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| }
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| 
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| /* abort execution with signal */
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| void QEMU_NORETURN force_sig(int sig)
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| {
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|     int host_sig;
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|     host_sig = target_to_host_signal(sig);
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|     fprintf(stderr, "qemu: uncaught target signal %d (%s) - exiting\n",
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|             sig, strsignal(host_sig));
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|     _exit(-host_sig);
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| }
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| 
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| /* queue a signal so that it will be send to the virtual CPU as soon
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|    as possible */
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| int queue_signal(int sig, target_siginfo_t *info)
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| {
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|     struct emulated_sigaction *k;
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|     struct sigqueue *q, **pq;
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|     target_ulong handler;
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| 
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| #if defined(DEBUG_SIGNAL)
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|     fprintf(stderr, "queue_signal: sig=%d\n",
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|             sig);
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| #endif
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|     k = &sigact_table[sig - 1];
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|     handler = (target_ulong)k->sa.sa_handler;
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|     if (handler == SIG_DFL) {
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|         /* default handler : ignore some signal. The other are fatal */
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|         if (sig != SIGCHLD &&
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|             sig != SIGURG &&
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|             sig != SIGWINCH) {
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|             force_sig(sig);
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|         } else {
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|             return 0; /* indicate ignored */
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|         }
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|     } else if (handler == host_to_target_signal(SIG_IGN)) {
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|         /* ignore signal */
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|         return 0;
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|     } else if (handler == host_to_target_signal(SIG_ERR)) {
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|         force_sig(sig);
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|     } else {
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|         pq = &k->first;
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|         if (!k->pending) {
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|             /* first signal */
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|             q = &k->info;
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|         } else {
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|             q = alloc_sigqueue();
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|             if (!q)
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|                 return -EAGAIN;
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|             while (*pq != NULL)
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|                 pq = &(*pq)->next;
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|         }
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|         *pq = q;
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|         q->info = *info;
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|         q->next = NULL;
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|         k->pending = 1;
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|         /* signal that a new signal is pending */
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|         signal_pending = 1;
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|         return 1; /* indicates that the signal was queued */
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|     }
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| }
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| 
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| static void host_signal_handler(int host_signum, siginfo_t *info,
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|                                 void *puc)
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| {
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|     int sig;
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|     target_siginfo_t tinfo;
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| 
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|     /* the CPU emulator uses some host signals to detect exceptions,
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|        we we forward to it some signals */
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|     if (host_signum == SIGSEGV || host_signum == SIGBUS) {
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|         if (cpu_signal_handler(host_signum, (void*)info, puc))
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|             return;
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|     }
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| 
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|     /* get target signal number */
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|     sig = host_to_target_signal(host_signum);
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|     if (sig < 1 || sig > NSIG)
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|         return;
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| 
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| #if defined(DEBUG_SIGNAL)
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| 	fprintf(stderr, "qemu: got signal %d\n", sig);
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| #endif
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|     if (queue_signal(sig, &tinfo) == 1) {
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|         /* interrupt the virtual CPU as soon as possible */
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|         cpu_exit(global_env);
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|     }
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| }
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| 
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| int do_sigaltstack(const struct sigaltstack *ss, struct sigaltstack *oss)
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| {
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|     /* XXX: test errors */
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|     if(oss)
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|     {
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|         oss->ss_sp = tswap32(target_sigaltstack_used.ss_sp);
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|         oss->ss_size = tswap32(target_sigaltstack_used.ss_size);
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|         oss->ss_flags = tswap32(target_sigaltstack_used.ss_flags);
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|     }
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|     if(ss)
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|     {
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|         target_sigaltstack_used.ss_sp = tswap32(ss->ss_sp);
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|         target_sigaltstack_used.ss_size = tswap32(ss->ss_size);
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|         target_sigaltstack_used.ss_flags = tswap32(ss->ss_flags);
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|     }
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|     return 0;
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| }
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| 
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| int do_sigaction(int sig, const struct sigaction *act,
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|                  struct sigaction *oact)
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| {
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|     struct emulated_sigaction *k;
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|     struct sigaction act1;
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|     int host_sig;
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| 
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|     if (sig < 1 || sig > NSIG)
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|         return -EINVAL;
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| 
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|     k = &sigact_table[sig - 1];
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| #if defined(DEBUG_SIGNAL)
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|     fprintf(stderr, "sigaction 1 sig=%d act=0x%08x, oact=0x%08x\n",
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|             sig, (int)act, (int)oact);
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| #endif
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|     if (oact) {
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| #if defined(DEBUG_SIGNAL)
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|     fprintf(stderr, "sigaction 1 sig=%d act=0x%08x, oact=0x%08x\n",
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|             sig, (int)act, (int)oact);
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| #endif
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| 
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|         oact->sa_handler = tswapl(k->sa.sa_handler);
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|         oact->sa_flags = tswapl(k->sa.sa_flags);
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|         oact->sa_mask = tswapl(k->sa.sa_mask);
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|     }
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|     if (act) {
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| #if defined(DEBUG_SIGNAL)
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|     fprintf(stderr, "sigaction handler 0x%x flag 0x%x mask 0x%x\n",
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|             act->sa_handler, act->sa_flags, act->sa_mask);
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| #endif
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| 
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|         k->sa.sa_handler = tswapl(act->sa_handler);
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|         k->sa.sa_flags = tswapl(act->sa_flags);
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|         k->sa.sa_mask = tswapl(act->sa_mask);
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|         /* we update the host signal state */
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|         host_sig = target_to_host_signal(sig);
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|         if (host_sig != SIGSEGV && host_sig != SIGBUS) {
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| #if defined(DEBUG_SIGNAL)
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|             fprintf(stderr, "sigaction handler going to call sigaction\n");
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| #endif
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| 
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|             sigfillset(&act1.sa_mask);
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|             act1.sa_flags = SA_SIGINFO;
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|             if (k->sa.sa_flags & SA_RESTART)
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|                 act1.sa_flags |= SA_RESTART;
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|             /* NOTE: it is important to update the host kernel signal
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|                ignore state to avoid getting unexpected interrupted
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|                syscalls */
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|             if (k->sa.sa_handler == SIG_IGN) {
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|                 act1.sa_sigaction = (void *)SIG_IGN;
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|             } else if (k->sa.sa_handler == SIG_DFL) {
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|                 act1.sa_sigaction = (void *)SIG_DFL;
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|             } else {
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|                 act1.sa_sigaction = host_signal_handler;
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|             }
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|             sigaction(host_sig, &act1, NULL);
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|         }
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|     }
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|     return 0;
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| }
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| 
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| 
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| #ifdef TARGET_I386
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| 
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| static inline void *
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| get_sigframe(struct emulated_sigaction *ka, CPUX86State *env, size_t frame_size)
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| {
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|     /* XXX Fix that */
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|     if(target_sigaltstack_used.ss_flags & SA_DISABLE)
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|     {
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|         int esp;
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|         /* Default to using normal stack */
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|         esp = env->regs[R_ESP];
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| 
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|         return (void *)((esp - frame_size) & -8ul);
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|     }
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|     else
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|     {
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|         return target_sigaltstack_used.ss_sp;
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|     }
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| }
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| 
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| static void setup_frame(int sig, struct emulated_sigaction *ka,
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| 			void *set, CPUState *env)
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| {
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| 	void *frame;
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| 
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|     fprintf(stderr, "setup_frame %d\n", sig);
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| 	frame = get_sigframe(ka, env, sizeof(*frame));
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| 
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| 	/* Set up registers for signal handler */
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| 	env->regs[R_ESP] = (unsigned long) frame;
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| 	env->eip = (unsigned long) ka->sa.sa_handler;
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| 
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| 	env->eflags &= ~TF_MASK;
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| 
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| 	return;
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| 
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| give_sigsegv:
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| 	if (sig == SIGSEGV)
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| 		ka->sa.sa_handler = SIG_DFL;
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| 	force_sig(SIGSEGV /* , current */);
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| }
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| 
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| long do_sigreturn(CPUState *env, int num)
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| {
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|     int i = 0;
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|     struct target_sigcontext *scp = get_int_arg(&i, env);
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|     /* XXX Get current signal number */
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|     /* XXX Adjust accordin to sc_onstack, sc_mask */
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|     if(tswapl(scp->sc_onstack) & 0x1)
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|         target_sigaltstack_used.ss_flags |= ~SA_DISABLE;
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|     else
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|         target_sigaltstack_used.ss_flags &=  SA_DISABLE;
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|     int set = tswapl(scp->sc_eax);
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|     sigprocmask(SIG_SETMASK, &set, NULL);
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| 
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|     fprintf(stderr, "do_sigreturn: partially implemented %x EAX:%x EBX:%x\n", scp->sc_mask, tswapl(scp->sc_eax), tswapl(scp->sc_ebx));
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|     fprintf(stderr, "ECX:%x EDX:%x EDI:%x\n", scp->sc_ecx, tswapl(scp->sc_edx), tswapl(scp->sc_edi));
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|     fprintf(stderr, "EIP:%x\n", tswapl(scp->sc_eip));
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| 
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|     env->regs[R_EAX] = tswapl(scp->sc_eax);
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|     env->regs[R_EBX] = tswapl(scp->sc_ebx);
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|     env->regs[R_ECX] = tswapl(scp->sc_ecx);
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|     env->regs[R_EDX] = tswapl(scp->sc_edx);
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|     env->regs[R_EDI] = tswapl(scp->sc_edi);
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|     env->regs[R_ESI] = tswapl(scp->sc_esi);
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|     env->regs[R_EBP] = tswapl(scp->sc_ebp);
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|     env->regs[R_ESP] = tswapl(scp->sc_esp);
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|     env->segs[R_SS].selector = (void*)tswapl(scp->sc_ss);
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|     env->eflags = tswapl(scp->sc_eflags);
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|     env->eip = tswapl(scp->sc_eip);
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|     env->segs[R_CS].selector = (void*)tswapl(scp->sc_cs);
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|     env->segs[R_DS].selector = (void*)tswapl(scp->sc_ds);
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|     env->segs[R_ES].selector = (void*)tswapl(scp->sc_es);
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|     env->segs[R_FS].selector = (void*)tswapl(scp->sc_fs);
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|     env->segs[R_GS].selector = (void*)tswapl(scp->sc_gs);
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| 
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|     /* Again, because our caller's caller will reset EAX */
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|     return env->regs[R_EAX];
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| }
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| 
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| #else
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| 
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| static void setup_frame(int sig, struct emulated_sigaction *ka,
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| 			void *set, CPUState *env)
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| {
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|     fprintf(stderr, "setup_frame: not implemented\n");
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| }
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| 
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| long do_sigreturn(CPUState *env, int num)
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| {
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|     int i = 0;
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|     struct target_sigcontext *scp = get_int_arg(&i, env);
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|     fprintf(stderr, "do_sigreturn: not implemented\n");
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|     return -ENOSYS;
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| }
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| 
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| #endif
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| 
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| void process_pending_signals(void *cpu_env)
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| {
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|     struct emulated_sigaction *k;
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|     struct sigqueue *q;
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|     target_ulong handler;
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|     int sig;
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| 
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|     if (!signal_pending)
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|         return;
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| 
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|     k = sigact_table;
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| 
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|     for(sig = 1; sig <= NSIG; sig++) {
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|         if (k->pending)
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|             goto handle_signal;
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|         k++;
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|     }
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| 
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|     /* if no signal is pending, just return */
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|     signal_pending = 0;
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|     return;
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| handle_signal:
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|     #ifdef DEBUG_SIGNAL
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|     fprintf(stderr, "qemu: process signal %d\n", sig);
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|     #endif
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|     /* dequeue signal */
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|     q = k->first;
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|     k->first = q->next;
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|     if (!k->first)
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|         k->pending = 0;
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| 
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|     sig = gdb_handlesig (cpu_env, sig);
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|     if (!sig) {
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|         fprintf (stderr, "Lost signal\n");
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|         abort();
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|     }
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| 
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|     handler = k->sa.sa_handler;
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|     if (handler == SIG_DFL) {
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|         /* default handler : ignore some signal. The other are fatal */
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|         if (sig != SIGCHLD &&
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|             sig != SIGURG &&
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|             sig != SIGWINCH) {
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|             force_sig(sig);
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|         }
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|     } else if (handler == SIG_IGN) {
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|         /* ignore sig */
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|     } else if (handler == SIG_ERR) {
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|         force_sig(sig);
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|     } else {
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| 
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|         setup_frame(sig, k, 0, cpu_env);
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| 	if (k->sa.sa_flags & SA_RESETHAND)
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|             k->sa.sa_handler = SIG_DFL;
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|     }
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|     if (q != &k->info)
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|         free_sigqueue(q);
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| }
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