/* * 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 #include #include #include #include #include #include #include #ifdef __ia64__ #undef uc_mcontext #undef uc_sigmask #undef uc_stack #undef uc_link #endif #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 emulated_sigaction sigact_table[TARGET_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); /* XXX: do it properly */ static inline int host_to_target_signal(int sig) { return sig; } static inline int target_to_host_signal(int sig) { return sig; } void host_to_target_sigset(target_sigset_t *d, sigset_t *s) { int i; for(i = 0;i < TARGET_NSIG_WORDS; i++) { d->sig[i] = tswapl(((unsigned long *)s)[i]); } } void target_to_host_sigset(sigset_t *d, target_sigset_t *s) { int i; for(i = 0;i < TARGET_NSIG_WORDS; i++) { ((unsigned long *)d)[i] = tswapl(s->sig[i]); } } void host_to_target_old_sigset(target_ulong *old_sigset, const sigset_t *sigset) { *old_sigset = tswap32(*(unsigned long *)sigset & 0xffffffff); } void target_to_host_old_sigset(sigset_t *sigset, const target_ulong *old_sigset) { sigemptyset(sigset); *(unsigned long *)sigset = tswapl(*old_sigset); } /* siginfo conversion */ static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo, const siginfo_t *info) { int sig; sig = host_to_target_signal(info->si_signo); tinfo->si_signo = sig; tinfo->si_errno = 0; tinfo->si_code = 0; if (sig == SIGILL || sig == SIGFPE || sig == SIGSEGV || sig == SIGBUS) { /* should never come here, but who knows. The information for the target is irrelevant */ tinfo->_sifields._sigfault._addr = 0; } else if (sig >= TARGET_SIGRTMIN) { tinfo->_sifields._rt._pid = info->si_pid; tinfo->_sifields._rt._uid = info->si_uid; /* XXX: potential problem if 64 bit */ tinfo->_sifields._rt._sigval.sival_ptr = (target_ulong)info->si_value.sival_ptr; } } static void tswap_siginfo(target_siginfo_t *tinfo, const target_siginfo_t *info) { int sig; sig = info->si_signo; tinfo->si_signo = tswap32(sig); tinfo->si_errno = tswap32(info->si_errno); tinfo->si_code = tswap32(info->si_code); if (sig == SIGILL || sig == SIGFPE || sig == SIGSEGV || sig == SIGBUS) { tinfo->_sifields._sigfault._addr = tswapl(info->_sifields._sigfault._addr); } else if (sig >= TARGET_SIGRTMIN) { tinfo->_sifields._rt._pid = tswap32(info->_sifields._rt._pid); tinfo->_sifields._rt._uid = tswap32(info->_sifields._rt._uid); tinfo->_sifields._rt._sigval.sival_ptr = tswapl(info->_sifields._rt._sigval.sival_ptr); } } void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info) { host_to_target_siginfo_noswap(tinfo, info); tswap_siginfo(tinfo, tinfo); } /* XXX: we support only POSIX RT signals are used. */ /* XXX: find a solution for 64 bit (additionnal malloced data is needed) */ void target_to_host_siginfo(siginfo_t *info, const target_siginfo_t *tinfo) { info->si_signo = tswap32(tinfo->si_signo); info->si_errno = tswap32(tinfo->si_errno); info->si_code = tswap32(tinfo->si_code); info->si_pid = tswap32(tinfo->_sifields._rt._pid); info->si_uid = tswap32(tinfo->_sifields._rt._uid); info->si_value.sival_ptr = (void *)tswapl(tinfo->_sifields._rt._sigval.sival_ptr); } 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)); #if 1 _exit(-host_sig); #else { struct sigaction act; sigemptyset(&act.sa_mask); act.sa_flags = SA_SIGINFO; act.sa_sigaction = SIG_DFL; sigaction(SIGABRT, &act, NULL); abort(); } #endif } /* 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 = k->sa._sa_handler; if (handler == TARGET_SIG_DFL) { /* default handler : ignore some signal. The other are fatal */ if (sig != TARGET_SIGCHLD && sig != TARGET_SIGURG && sig != TARGET_SIGWINCH) { force_sig(sig); } else { return 0; /* indicate ignored */ } } else if (handler == TARGET_SIG_IGN) { /* ignore signal */ return 0; } else if (handler == TARGET_SIG_ERR) { force_sig(sig); } else { pq = &k->first; if (sig < TARGET_SIGRTMIN) { /* if non real time signal, we queue exactly one signal */ if (!k->pending) q = &k->info; else return 0; } else { 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 */ } } #if defined(DEBUG_SIGNAL) #ifdef __i386__ static void dump_regs(struct ucontext *uc) { fprintf(stderr, "EAX=%08x EBX=%08x ECX=%08x EDX=%08x\n" "ESI=%08x EDI=%08x EBP=%08x ESP=%08x\n" "EFL=%08x EIP=%08x\n", uc->uc_mcontext.gregs[EAX], uc->uc_mcontext.gregs[EBX], uc->uc_mcontext.gregs[ECX], uc->uc_mcontext.gregs[EDX], uc->uc_mcontext.gregs[ESI], uc->uc_mcontext.gregs[EDI], uc->uc_mcontext.gregs[EBP], uc->uc_mcontext.gregs[ESP], uc->uc_mcontext.gregs[EFL], uc->uc_mcontext.gregs[EIP]); } #else static void dump_regs(struct ucontext *uc) { } #endif #endif 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_x86_signal_handler(host_signum, info, puc)) return; } /* get target signal number */ sig = host_to_target_signal(host_signum); if (sig < 1 || sig > TARGET_NSIG) return; #if defined(DEBUG_SIGNAL) fprintf(stderr, "qemu: got signal %d\n", sig); dump_regs(puc); #endif host_to_target_siginfo_noswap(&tinfo, info); if (queue_signal(sig, &tinfo) == 1) { /* interrupt the virtual CPU as soon as possible */ cpu_x86_interrupt(global_env); } } int do_sigaction(int sig, const struct target_sigaction *act, struct target_sigaction *oact) { struct emulated_sigaction *k; if (sig < 1 || sig > TARGET_NSIG) return -EINVAL; k = &sigact_table[sig - 1]; #if defined(DEBUG_SIGNAL) && 0 fprintf(stderr, "sigaction sig=%d act=0x%08x, oact=0x%08x\n", sig, (int)act, (int)oact); #endif if (oact) { oact->_sa_handler = tswapl(k->sa._sa_handler); oact->sa_flags = tswapl(k->sa.sa_flags); oact->sa_restorer = tswapl(k->sa.sa_restorer); oact->sa_mask = k->sa.sa_mask; } if (act) { k->sa._sa_handler = tswapl(act->_sa_handler); k->sa.sa_flags = tswapl(act->sa_flags); k->sa.sa_restorer = tswapl(act->sa_restorer); k->sa.sa_mask = act->sa_mask; } return 0; } #ifdef TARGET_I386 /* from the Linux kernel */ struct target_fpreg { uint16_t significand[4]; uint16_t exponent; }; struct target_fpxreg { uint16_t significand[4]; uint16_t exponent; uint16_t padding[3]; }; struct target_xmmreg { target_ulong element[4]; }; struct target_fpstate { /* Regular FPU environment */ target_ulong cw; target_ulong sw; target_ulong tag; target_ulong ipoff; target_ulong cssel; target_ulong dataoff; target_ulong datasel; struct target_fpreg _st[8]; uint16_t status; uint16_t magic; /* 0xffff = regular FPU data only */ /* FXSR FPU environment */ target_ulong _fxsr_env[6]; /* FXSR FPU env is ignored */ target_ulong mxcsr; target_ulong reserved; struct target_fpxreg _fxsr_st[8]; /* FXSR FPU reg data is ignored */ struct target_xmmreg _xmm[8]; target_ulong padding[56]; }; #define X86_FXSR_MAGIC 0x0000 struct target_sigcontext { uint16_t gs, __gsh; uint16_t fs, __fsh; uint16_t es, __esh; uint16_t ds, __dsh; target_ulong edi; target_ulong esi; target_ulong ebp; target_ulong esp; target_ulong ebx; target_ulong edx; target_ulong ecx; target_ulong eax; target_ulong trapno; target_ulong err; target_ulong eip; uint16_t cs, __csh; target_ulong eflags; target_ulong esp_at_signal; uint16_t ss, __ssh; target_ulong fpstate; /* pointer */ target_ulong oldmask; target_ulong cr2; }; typedef struct target_sigaltstack { target_ulong ss_sp; int ss_flags; target_ulong ss_size; } target_stack_t; struct target_ucontext { target_ulong uc_flags; target_ulong uc_link; target_stack_t uc_stack; struct target_sigcontext uc_mcontext; target_sigset_t uc_sigmask; /* mask last for extensibility */ }; struct sigframe { target_ulong pretcode; int sig; struct target_sigcontext sc; struct target_fpstate fpstate; target_ulong extramask[TARGET_NSIG_WORDS-1]; char retcode[8]; }; struct rt_sigframe { target_ulong pretcode; int sig; target_ulong pinfo; target_ulong puc; struct target_siginfo info; struct target_ucontext uc; struct target_fpstate fpstate; char retcode[8]; }; /* * Set up a signal frame. */ #define __put_user(x,ptr)\ ({\ int size = sizeof(*ptr);\ switch(size) {\ case 1:\ stb(ptr, (typeof(*ptr))(x));\ break;\ case 2:\ stw(ptr, (typeof(*ptr))(x));\ break;\ case 4:\ stl(ptr, (typeof(*ptr))(x));\ break;\ case 8:\ stq(ptr, (typeof(*ptr))(x));\ break;\ default:\ abort();\ }\ 0;\ }) #define get_user(val, ptr) (typeof(*ptr))(*(ptr)) #define __copy_to_user(dst, src, size)\ ({\ memcpy(dst, src, size);\ 0;\ }) static inline int copy_siginfo_to_user(target_siginfo_t *tinfo, const target_siginfo_t *info) { tswap_siginfo(tinfo, info); return 0; } /* XXX: save x87 state */ static int setup_sigcontext(struct target_sigcontext *sc, struct target_fpstate *fpstate, CPUX86State *env, unsigned long mask) { int err = 0; err |= __put_user(env->segs[R_GS], (unsigned int *)&sc->gs); err |= __put_user(env->segs[R_FS], (unsigned int *)&sc->fs); err |= __put_user(env->segs[R_ES], (unsigned int *)&sc->es); err |= __put_user(env->segs[R_DS], (unsigned int *)&sc->ds); err |= __put_user(env->regs[R_EDI], &sc->edi); err |= __put_user(env->regs[R_ESI], &sc->esi); err |= __put_user(env->regs[R_EBP], &sc->ebp); err |= __put_user(env->regs[R_ESP], &sc->esp); err |= __put_user(env->regs[R_EBX], &sc->ebx); err |= __put_user(env->regs[R_EDX], &sc->edx); err |= __put_user(env->regs[R_ECX], &sc->ecx); err |= __put_user(env->regs[R_EAX], &sc->eax); err |= __put_user(env->exception_index, &sc->trapno); err |= __put_user(env->error_code, &sc->err); err |= __put_user(env->eip, &sc->eip); err |= __put_user(env->segs[R_CS], (unsigned int *)&sc->cs); err |= __put_user(env->eflags, &sc->eflags); err |= __put_user(env->regs[R_ESP], &sc->esp_at_signal); err |= __put_user(env->segs[R_SS], (unsigned int *)&sc->ss); #if 0 tmp = save_i387(fpstate); if (tmp < 0) err = 1; else err |= __put_user(tmp ? fpstate : NULL, &sc->fpstate); #else err |= __put_user(0, &sc->fpstate); #endif /* non-iBCS2 extensions.. */ err |= __put_user(mask, &sc->oldmask); err |= __put_user(/*current->thread.cr2*/ 0, &sc->cr2); return err; } /* * Determine which stack to use.. */ static inline void * get_sigframe(struct emulated_sigaction *ka, CPUX86State *env, size_t frame_size) { unsigned long esp; /* Default to using normal stack */ esp = env->regs[R_ESP]; #if 0 /* This is the X/Open sanctioned signal stack switching. */ if (ka->sa.sa_flags & SA_ONSTACK) { if (sas_ss_flags(esp) == 0) esp = current->sas_ss_sp + current->sas_ss_size; } /* This is the legacy signal stack switching. */ else if ((regs->xss & 0xffff) != __USER_DS && !(ka->sa.sa_flags & SA_RESTORER) && ka->sa.sa_restorer) { esp = (unsigned long) ka->sa.sa_restorer; } #endif return (void *)((esp - frame_size) & -8ul); } static void setup_frame(int sig, struct emulated_sigaction *ka, target_sigset_t *set, CPUX86State *env) { struct sigframe *frame; int err = 0; frame = get_sigframe(ka, env, sizeof(*frame)); #if 0 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) goto give_sigsegv; #endif err |= __put_user((/*current->exec_domain && current->exec_domain->signal_invmap && sig < 32 ? current->exec_domain->signal_invmap[sig] : */ sig), &frame->sig); if (err) goto give_sigsegv; setup_sigcontext(&frame->sc, &frame->fpstate, env, set->sig[0]); if (err) goto give_sigsegv; if (TARGET_NSIG_WORDS > 1) { err |= __copy_to_user(frame->extramask, &set->sig[1], sizeof(frame->extramask)); } if (err) goto give_sigsegv; /* Set up to return from userspace. If provided, use a stub already in userspace. */ if (ka->sa.sa_flags & TARGET_SA_RESTORER) { err |= __put_user(ka->sa.sa_restorer, &frame->pretcode); } else { err |= __put_user(frame->retcode, &frame->pretcode); /* This is popl %eax ; movl $,%eax ; int $0x80 */ err |= __put_user(0xb858, (short *)(frame->retcode+0)); err |= __put_user(TARGET_NR_sigreturn, (int *)(frame->retcode+2)); err |= __put_user(0x80cd, (short *)(frame->retcode+6)); } if (err) goto give_sigsegv; /* Set up registers for signal handler */ env->regs[R_ESP] = (unsigned long) frame; env->eip = (unsigned long) ka->sa._sa_handler; cpu_x86_load_seg(env, R_DS, __USER_DS); cpu_x86_load_seg(env, R_ES, __USER_DS); cpu_x86_load_seg(env, R_SS, __USER_DS); cpu_x86_load_seg(env, R_CS, __USER_CS); env->eflags &= ~TF_MASK; return; give_sigsegv: if (sig == TARGET_SIGSEGV) ka->sa._sa_handler = TARGET_SIG_DFL; force_sig(TARGET_SIGSEGV /* , current */); } static void setup_rt_frame(int sig, struct emulated_sigaction *ka, target_siginfo_t *info, target_sigset_t *set, CPUX86State *env) { struct rt_sigframe *frame; int err = 0; frame = get_sigframe(ka, env, sizeof(*frame)); #if 0 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) goto give_sigsegv; #endif err |= __put_user((/*current->exec_domain && current->exec_domain->signal_invmap && sig < 32 ? current->exec_domain->signal_invmap[sig] : */sig), &frame->sig); err |= __put_user((target_ulong)&frame->info, &frame->pinfo); err |= __put_user((target_ulong)&frame->uc, &frame->puc); err |= copy_siginfo_to_user(&frame->info, info); if (err) goto give_sigsegv; /* Create the ucontext. */ err |= __put_user(0, &frame->uc.uc_flags); err |= __put_user(0, &frame->uc.uc_link); err |= __put_user(/*current->sas_ss_sp*/ 0, &frame->uc.uc_stack.ss_sp); err |= __put_user(/* sas_ss_flags(regs->esp) */ 0, &frame->uc.uc_stack.ss_flags); err |= __put_user(/* current->sas_ss_size */ 0, &frame->uc.uc_stack.ss_size); err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->fpstate, env, set->sig[0]); err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); if (err) goto give_sigsegv; /* Set up to return from userspace. If provided, use a stub already in userspace. */ if (ka->sa.sa_flags & TARGET_SA_RESTORER) { err |= __put_user(ka->sa.sa_restorer, &frame->pretcode); } else { err |= __put_user(frame->retcode, &frame->pretcode); /* This is movl $,%eax ; int $0x80 */ err |= __put_user(0xb8, (char *)(frame->retcode+0)); err |= __put_user(TARGET_NR_rt_sigreturn, (int *)(frame->retcode+1)); err |= __put_user(0x80cd, (short *)(frame->retcode+5)); } if (err) goto give_sigsegv; /* Set up registers for signal handler */ env->regs[R_ESP] = (unsigned long) frame; env->eip = (unsigned long) ka->sa._sa_handler; cpu_x86_load_seg(env, R_DS, __USER_DS); cpu_x86_load_seg(env, R_ES, __USER_DS); cpu_x86_load_seg(env, R_SS, __USER_DS); cpu_x86_load_seg(env, R_CS, __USER_CS); env->eflags &= ~TF_MASK; return; give_sigsegv: if (sig == TARGET_SIGSEGV) ka->sa._sa_handler = TARGET_SIG_DFL; force_sig(TARGET_SIGSEGV /* , current */); } static int restore_sigcontext(CPUX86State *env, struct target_sigcontext *sc, int *peax) { unsigned int err = 0; #define COPY(x) err |= __get_user(regs->x, &sc->x) #define COPY_SEG(seg) \ { unsigned short tmp; \ err |= __get_user(tmp, &sc->seg); \ regs->x##seg = tmp; } #define COPY_SEG_STRICT(seg) \ { unsigned short tmp; \ err |= __get_user(tmp, &sc->seg); \ regs->x##seg = tmp|3; } #define GET_SEG(seg) \ { unsigned short tmp; \ err |= __get_user(tmp, &sc->seg); \ loadsegment(seg,tmp); } cpu_x86_load_seg(env, R_GS, lduw(&sc->gs)); cpu_x86_load_seg(env, R_FS, lduw(&sc->fs)); cpu_x86_load_seg(env, R_ES, lduw(&sc->es)); cpu_x86_load_seg(env, R_DS, lduw(&sc->ds)); env->regs[R_EDI] = ldl(&sc->edi); env->regs[R_ESI] = ldl(&sc->esi); env->regs[R_EBP] = ldl(&sc->ebp); env->regs[R_ESP] = ldl(&sc->esp); env->regs[R_EBX] = ldl(&sc->ebx); env->regs[R_EDX] = ldl(&sc->edx); env->regs[R_ECX] = ldl(&sc->ecx); env->eip = ldl(&sc->eip); cpu_x86_load_seg(env, R_CS, lduw(&sc->cs) | 3); cpu_x86_load_seg(env, R_SS, lduw(&sc->ss) | 3); { unsigned int tmpflags; tmpflags = ldl(&sc->eflags); env->eflags = (env->eflags & ~0x40DD5) | (tmpflags & 0x40DD5); // regs->orig_eax = -1; /* disable syscall checks */ } #if 0 { struct _fpstate * buf; err |= __get_user(buf, &sc->fpstate); if (buf) { if (verify_area(VERIFY_READ, buf, sizeof(*buf))) goto badframe; err |= restore_i387(buf); } } #endif *peax = ldl(&sc->eax); return err; #if 0 badframe: return 1; #endif } long do_sigreturn(CPUX86State *env) { struct sigframe *frame = (struct sigframe *)(env->regs[R_ESP] - 8); target_sigset_t target_set; sigset_t set; int eax, i; /* set blocked signals */ target_set.sig[0] = frame->sc.oldmask; for(i = 1; i < TARGET_NSIG_WORDS; i++) target_set.sig[i] = frame->extramask[i - 1]; target_to_host_sigset(&set, &target_set); sigprocmask(SIG_SETMASK, &set, NULL); /* restore registers */ if (restore_sigcontext(env, &frame->sc, &eax)) goto badframe; return eax; badframe: force_sig(TARGET_SIGSEGV); return 0; } long do_rt_sigreturn(CPUX86State *env) { struct rt_sigframe *frame = (struct rt_sigframe *)(env->regs[R_ESP] - 4); target_sigset_t target_set; sigset_t set; // stack_t st; int eax; #if 0 if (verify_area(VERIFY_READ, frame, sizeof(*frame))) goto badframe; #endif memcpy(&target_set, &frame->uc.uc_sigmask, sizeof(target_sigset_t)); target_to_host_sigset(&set, &target_set); sigprocmask(SIG_SETMASK, &set, NULL); if (restore_sigcontext(env, &frame->uc.uc_mcontext, &eax)) goto badframe; #if 0 if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st))) goto badframe; /* It is more difficult to avoid calling this function than to call it and ignore errors. */ do_sigaltstack(&st, NULL, regs->esp); #endif return eax; badframe: force_sig(TARGET_SIGSEGV); return 0; } #endif void process_pending_signals(void *cpu_env) { int sig; target_ulong handler; sigset_t set, old_set; target_sigset_t target_old_set; struct emulated_sigaction *k; struct sigqueue *q; if (!signal_pending) return; k = sigact_table; for(sig = 1; sig <= TARGET_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; handler = k->sa._sa_handler; if (handler == TARGET_SIG_DFL) { /* default handler : ignore some signal. The other are fatal */ if (sig != TARGET_SIGCHLD && sig != TARGET_SIGURG && sig != TARGET_SIGWINCH) { force_sig(sig); } } else if (handler == TARGET_SIG_IGN) { /* ignore sig */ } else if (handler == TARGET_SIG_ERR) { force_sig(sig); } else { /* compute the blocked signals during the handler execution */ target_to_host_sigset(&set, &k->sa.sa_mask); /* SA_NODEFER indicates that the current signal should not be blocked during the handler */ if (!(k->sa.sa_flags & TARGET_SA_NODEFER)) sigaddset(&set, target_to_host_signal(sig)); /* block signals in the handler using Linux */ sigprocmask(SIG_BLOCK, &set, &old_set); /* save the previous blocked signal state to restore it at the end of the signal execution (see do_sigreturn) */ host_to_target_sigset(&target_old_set, &old_set); /* if the CPU is in VM86 mode, we restore the 32 bit values */ #ifdef TARGET_I386 { CPUX86State *env = cpu_env; if (env->eflags & VM_MASK) save_v86_state(env); } #endif /* prepare the stack frame of the virtual CPU */ if (k->sa.sa_flags & TARGET_SA_SIGINFO) setup_rt_frame(sig, k, &q->info, &target_old_set, cpu_env); else setup_frame(sig, k, &target_old_set, cpu_env); if (k->sa.sa_flags & TARGET_SA_RESETHAND) k->sa._sa_handler = TARGET_SIG_DFL; } if (q != &k->info) free_sigqueue(q); }