/* * Emulation of BSD signals * * Copyright (c) 2003 - 2008 Fabrice Bellard * Copyright (c) 2013 Stacey Son * * 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, see . */ #include "qemu/osdep.h" #include "qemu/log.h" #include "qemu.h" #include "gdbstub/user.h" #include "signal-common.h" #include "trace.h" #include "hw/core/tcg-cpu-ops.h" #include "host-signal.h" static struct target_sigaction sigact_table[TARGET_NSIG]; static void host_signal_handler(int host_sig, siginfo_t *info, void *puc); static void target_to_host_sigset_internal(sigset_t *d, const target_sigset_t *s); static inline int on_sig_stack(TaskState *ts, unsigned long sp) { return sp - ts->sigaltstack_used.ss_sp < ts->sigaltstack_used.ss_size; } static inline int sas_ss_flags(TaskState *ts, unsigned long sp) { return ts->sigaltstack_used.ss_size == 0 ? SS_DISABLE : on_sig_stack(ts, sp) ? SS_ONSTACK : 0; } /* * The BSD ABIs use the same signal numbers across all the CPU architectures, so * (unlike Linux) these functions are just the identity mapping. This might not * be true for XyzBSD running on AbcBSD, which doesn't currently work. */ int host_to_target_signal(int sig) { return sig; } int target_to_host_signal(int sig) { return sig; } static inline void target_sigemptyset(target_sigset_t *set) { memset(set, 0, sizeof(*set)); } static inline void target_sigaddset(target_sigset_t *set, int signum) { signum--; uint32_t mask = (uint32_t)1 << (signum % TARGET_NSIG_BPW); set->__bits[signum / TARGET_NSIG_BPW] |= mask; } static inline int target_sigismember(const target_sigset_t *set, int signum) { signum--; abi_ulong mask = (abi_ulong)1 << (signum % TARGET_NSIG_BPW); return (set->__bits[signum / TARGET_NSIG_BPW] & mask) != 0; } /* Adjust the signal context to rewind out of safe-syscall if we're in it */ static inline void rewind_if_in_safe_syscall(void *puc) { ucontext_t *uc = (ucontext_t *)puc; uintptr_t pcreg = host_signal_pc(uc); if (pcreg > (uintptr_t)safe_syscall_start && pcreg < (uintptr_t)safe_syscall_end) { host_signal_set_pc(uc, (uintptr_t)safe_syscall_start); } } /* * Note: The following take advantage of the BSD signal property that all * signals are available on all architectures. */ static void host_to_target_sigset_internal(target_sigset_t *d, const sigset_t *s) { int i; target_sigemptyset(d); for (i = 1; i <= NSIG; i++) { if (sigismember(s, i)) { target_sigaddset(d, host_to_target_signal(i)); } } } void host_to_target_sigset(target_sigset_t *d, const sigset_t *s) { target_sigset_t d1; int i; host_to_target_sigset_internal(&d1, s); for (i = 0; i < _SIG_WORDS; i++) { d->__bits[i] = tswap32(d1.__bits[i]); } } static void target_to_host_sigset_internal(sigset_t *d, const target_sigset_t *s) { int i; sigemptyset(d); for (i = 1; i <= TARGET_NSIG; i++) { if (target_sigismember(s, i)) { sigaddset(d, target_to_host_signal(i)); } } } void target_to_host_sigset(sigset_t *d, const target_sigset_t *s) { target_sigset_t s1; int i; for (i = 0; i < TARGET_NSIG_WORDS; i++) { s1.__bits[i] = tswap32(s->__bits[i]); } target_to_host_sigset_internal(d, &s1); } static bool has_trapno(int tsig) { return tsig == TARGET_SIGILL || tsig == TARGET_SIGFPE || tsig == TARGET_SIGSEGV || tsig == TARGET_SIGBUS || tsig == TARGET_SIGTRAP; } /* Siginfo conversion. */ /* * Populate tinfo w/o swapping based on guessing which fields are valid. */ static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo, const siginfo_t *info) { int sig = host_to_target_signal(info->si_signo); int si_code = info->si_code; int si_type; /* * Make sure we that the variable portion of the target siginfo is zeroed * out so we don't leak anything into that. */ memset(&tinfo->_reason, 0, sizeof(tinfo->_reason)); /* * This is awkward, because we have to use a combination of the si_code and * si_signo to figure out which of the union's members are valid.o We * therefore make our best guess. * * Once we have made our guess, we record it in the top 16 bits of * the si_code, so that tswap_siginfo() later can use it. * tswap_siginfo() will strip these top bits out before writing * si_code to the guest (sign-extending the lower bits). */ tinfo->si_signo = sig; tinfo->si_errno = info->si_errno; tinfo->si_code = info->si_code; tinfo->si_pid = info->si_pid; tinfo->si_uid = info->si_uid; tinfo->si_status = info->si_status; tinfo->si_addr = (abi_ulong)(unsigned long)info->si_addr; /* * si_value is opaque to kernel. On all FreeBSD platforms, * sizeof(sival_ptr) >= sizeof(sival_int) so the following * always will copy the larger element. */ tinfo->si_value.sival_ptr = (abi_ulong)(unsigned long)info->si_value.sival_ptr; switch (si_code) { /* * All the SI_xxx codes that are defined here are global to * all the signals (they have values that none of the other, * more specific signal info will set). */ case SI_USER: case SI_LWP: case SI_KERNEL: case SI_QUEUE: case SI_ASYNCIO: /* * Only the fixed parts are valid (though FreeBSD doesn't always * set all the fields to non-zero values. */ si_type = QEMU_SI_NOINFO; break; case SI_TIMER: tinfo->_reason._timer._timerid = info->_reason._timer._timerid; tinfo->_reason._timer._overrun = info->_reason._timer._overrun; si_type = QEMU_SI_TIMER; break; case SI_MESGQ: tinfo->_reason._mesgq._mqd = info->_reason._mesgq._mqd; si_type = QEMU_SI_MESGQ; break; default: /* * We have to go based on the signal number now to figure out * what's valid. */ si_type = QEMU_SI_NOINFO; if (has_trapno(sig)) { tinfo->_reason._fault._trapno = info->_reason._fault._trapno; si_type = QEMU_SI_FAULT; } #ifdef TARGET_SIGPOLL /* * FreeBSD never had SIGPOLL, but emulates it for Linux so there's * a chance it may popup in the future. */ if (sig == TARGET_SIGPOLL) { tinfo->_reason._poll._band = info->_reason._poll._band; si_type = QEMU_SI_POLL; } #endif /* * Unsure that this can actually be generated, and our support for * capsicum is somewhere between weak and non-existent, but if we get * one, then we know what to save. */ #ifdef QEMU_SI_CAPSICUM if (sig == TARGET_SIGTRAP) { tinfo->_reason._capsicum._syscall = info->_reason._capsicum._syscall; si_type = QEMU_SI_CAPSICUM; } #endif break; } tinfo->si_code = deposit32(si_code, 24, 8, si_type); } static void tswap_siginfo(target_siginfo_t *tinfo, const target_siginfo_t *info) { int si_type = extract32(info->si_code, 24, 8); int si_code = sextract32(info->si_code, 0, 24); __put_user(info->si_signo, &tinfo->si_signo); __put_user(info->si_errno, &tinfo->si_errno); __put_user(si_code, &tinfo->si_code); /* Zero out si_type, it's internal */ __put_user(info->si_pid, &tinfo->si_pid); __put_user(info->si_uid, &tinfo->si_uid); __put_user(info->si_status, &tinfo->si_status); __put_user(info->si_addr, &tinfo->si_addr); /* * Unswapped, because we passed it through mostly untouched. si_value is * opaque to the kernel, so we didn't bother with potentially wasting cycles * to swap it into host byte order. */ tinfo->si_value.sival_ptr = info->si_value.sival_ptr; /* * We can use our internal marker of which fields in the structure * are valid, rather than duplicating the guesswork of * host_to_target_siginfo_noswap() here. */ switch (si_type) { case QEMU_SI_NOINFO: /* No additional info */ break; case QEMU_SI_FAULT: __put_user(info->_reason._fault._trapno, &tinfo->_reason._fault._trapno); break; case QEMU_SI_TIMER: __put_user(info->_reason._timer._timerid, &tinfo->_reason._timer._timerid); __put_user(info->_reason._timer._overrun, &tinfo->_reason._timer._overrun); break; case QEMU_SI_MESGQ: __put_user(info->_reason._mesgq._mqd, &tinfo->_reason._mesgq._mqd); break; case QEMU_SI_POLL: /* Note: Not generated on FreeBSD */ __put_user(info->_reason._poll._band, &tinfo->_reason._poll._band); break; #ifdef QEMU_SI_CAPSICUM case QEMU_SI_CAPSICUM: __put_user(info->_reason._capsicum._syscall, &tinfo->_reason._capsicum._syscall); break; #endif default: g_assert_not_reached(); } } void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info) { host_to_target_siginfo_noswap(tinfo, info); tswap_siginfo(tinfo, tinfo); } int block_signals(void) { TaskState *ts = (TaskState *)thread_cpu->opaque; sigset_t set; /* * It's OK to block everything including SIGSEGV, because we won't run any * further guest code before unblocking signals in * process_pending_signals(). We depend on the FreeBSD behavior here where * this will only affect this thread's signal mask. We don't use * pthread_sigmask which might seem more correct because that routine also * does odd things with SIGCANCEL to implement pthread_cancel(). */ sigfillset(&set); sigprocmask(SIG_SETMASK, &set, 0); return qatomic_xchg(&ts->signal_pending, 1); } /* Returns 1 if given signal should dump core if not handled. */ static int core_dump_signal(int sig) { switch (sig) { case TARGET_SIGABRT: case TARGET_SIGFPE: case TARGET_SIGILL: case TARGET_SIGQUIT: case TARGET_SIGSEGV: case TARGET_SIGTRAP: case TARGET_SIGBUS: return 1; default: return 0; } } /* Abort execution with signal. */ static G_NORETURN void dump_core_and_abort(int target_sig) { CPUState *cpu = thread_cpu; CPUArchState *env = cpu_env(cpu); TaskState *ts = cpu->opaque; int core_dumped = 0; int host_sig; struct sigaction act; host_sig = target_to_host_signal(target_sig); gdb_signalled(env, target_sig); /* Dump core if supported by target binary format */ if (core_dump_signal(target_sig) && (ts->bprm->core_dump != NULL)) { stop_all_tasks(); core_dumped = ((*ts->bprm->core_dump)(target_sig, env) == 0); } if (core_dumped) { struct rlimit nodump; /* * We already dumped the core of target process, we don't want * a coredump of qemu itself. */ getrlimit(RLIMIT_CORE, &nodump); nodump.rlim_cur = 0; setrlimit(RLIMIT_CORE, &nodump); (void) fprintf(stderr, "qemu: uncaught target signal %d (%s) " "- %s\n", target_sig, strsignal(host_sig), "core dumped"); } /* * The proper exit code for dying from an uncaught signal is * -. The kernel doesn't allow exit() or _exit() to pass * a negative value. To get the proper exit code we need to * actually die from an uncaught signal. Here the default signal * handler is installed, we send ourself a signal and we wait for * it to arrive. */ memset(&act, 0, sizeof(act)); sigfillset(&act.sa_mask); act.sa_handler = SIG_DFL; sigaction(host_sig, &act, NULL); kill(getpid(), host_sig); /* * Make sure the signal isn't masked (just reuse the mask inside * of act). */ sigdelset(&act.sa_mask, host_sig); sigsuspend(&act.sa_mask); /* unreachable */ abort(); } /* * Queue a signal so that it will be send to the virtual CPU as soon as * possible. */ void queue_signal(CPUArchState *env, int sig, int si_type, target_siginfo_t *info) { CPUState *cpu = env_cpu(env); TaskState *ts = cpu->opaque; trace_user_queue_signal(env, sig); info->si_code = deposit32(info->si_code, 24, 8, si_type); ts->sync_signal.info = *info; ts->sync_signal.pending = sig; /* Signal that a new signal is pending. */ qatomic_set(&ts->signal_pending, 1); return; } static int fatal_signal(int sig) { switch (sig) { case TARGET_SIGCHLD: case TARGET_SIGURG: case TARGET_SIGWINCH: case TARGET_SIGINFO: /* Ignored by default. */ return 0; case TARGET_SIGCONT: case TARGET_SIGSTOP: case TARGET_SIGTSTP: case TARGET_SIGTTIN: case TARGET_SIGTTOU: /* Job control signals. */ return 0; default: return 1; } } /* * Force a synchronously taken QEMU_SI_FAULT signal. For QEMU the * 'force' part is handled in process_pending_signals(). */ void force_sig_fault(int sig, int code, abi_ulong addr) { CPUState *cpu = thread_cpu; CPUArchState *env = cpu_env(cpu); target_siginfo_t info = {}; info.si_signo = sig; info.si_errno = 0; info.si_code = code; info.si_addr = addr; queue_signal(env, sig, QEMU_SI_FAULT, &info); } static void host_signal_handler(int host_sig, siginfo_t *info, void *puc) { CPUState *cpu = thread_cpu; TaskState *ts = cpu->opaque; target_siginfo_t tinfo; ucontext_t *uc = puc; struct emulated_sigtable *k; int guest_sig; uintptr_t pc = 0; bool sync_sig = false; /* * Non-spoofed SIGSEGV and SIGBUS are synchronous, and need special * handling wrt signal blocking and unwinding. */ if ((host_sig == SIGSEGV || host_sig == SIGBUS) && info->si_code > 0) { MMUAccessType access_type; uintptr_t host_addr; abi_ptr guest_addr; bool is_write; host_addr = (uintptr_t)info->si_addr; /* * Convert forcefully to guest address space: addresses outside * reserved_va are still valid to report via SEGV_MAPERR. */ guest_addr = h2g_nocheck(host_addr); pc = host_signal_pc(uc); is_write = host_signal_write(info, uc); access_type = adjust_signal_pc(&pc, is_write); if (host_sig == SIGSEGV) { bool maperr = true; if (info->si_code == SEGV_ACCERR && h2g_valid(host_addr)) { /* If this was a write to a TB protected page, restart. */ if (is_write && handle_sigsegv_accerr_write(cpu, &uc->uc_sigmask, pc, guest_addr)) { return; } /* * With reserved_va, the whole address space is PROT_NONE, * which means that we may get ACCERR when we want MAPERR. */ if (page_get_flags(guest_addr) & PAGE_VALID) { maperr = false; } else { info->si_code = SEGV_MAPERR; } } sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL); cpu_loop_exit_sigsegv(cpu, guest_addr, access_type, maperr, pc); } else { sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL); if (info->si_code == BUS_ADRALN) { cpu_loop_exit_sigbus(cpu, guest_addr, access_type, pc); } } sync_sig = true; } /* Get the target signal number. */ guest_sig = host_to_target_signal(host_sig); if (guest_sig < 1 || guest_sig > TARGET_NSIG) { return; } trace_user_host_signal(cpu, host_sig, guest_sig); host_to_target_siginfo_noswap(&tinfo, info); k = &ts->sigtab[guest_sig - 1]; k->info = tinfo; k->pending = guest_sig; ts->signal_pending = 1; /* * For synchronous signals, unwind the cpu state to the faulting * insn and then exit back to the main loop so that the signal * is delivered immediately. */ if (sync_sig) { cpu->exception_index = EXCP_INTERRUPT; cpu_loop_exit_restore(cpu, pc); } rewind_if_in_safe_syscall(puc); /* * Block host signals until target signal handler entered. We * can't block SIGSEGV or SIGBUS while we're executing guest * code in case the guest code provokes one in the window between * now and it getting out to the main loop. Signals will be * unblocked again in process_pending_signals(). */ sigfillset(&uc->uc_sigmask); sigdelset(&uc->uc_sigmask, SIGSEGV); sigdelset(&uc->uc_sigmask, SIGBUS); /* Interrupt the virtual CPU as soon as possible. */ cpu_exit(thread_cpu); } /* do_sigaltstack() returns target values and errnos. */ /* compare to kern/kern_sig.c sys_sigaltstack() and kern_sigaltstack() */ abi_long do_sigaltstack(abi_ulong uss_addr, abi_ulong uoss_addr, abi_ulong sp) { TaskState *ts = (TaskState *)thread_cpu->opaque; int ret; target_stack_t oss; if (uoss_addr) { /* Save current signal stack params */ oss.ss_sp = tswapl(ts->sigaltstack_used.ss_sp); oss.ss_size = tswapl(ts->sigaltstack_used.ss_size); oss.ss_flags = tswapl(sas_ss_flags(ts, sp)); } if (uss_addr) { target_stack_t *uss; target_stack_t ss; size_t minstacksize = TARGET_MINSIGSTKSZ; ret = -TARGET_EFAULT; if (!lock_user_struct(VERIFY_READ, uss, uss_addr, 1)) { goto out; } __get_user(ss.ss_sp, &uss->ss_sp); __get_user(ss.ss_size, &uss->ss_size); __get_user(ss.ss_flags, &uss->ss_flags); unlock_user_struct(uss, uss_addr, 0); ret = -TARGET_EPERM; if (on_sig_stack(ts, sp)) { goto out; } ret = -TARGET_EINVAL; if (ss.ss_flags != TARGET_SS_DISABLE && ss.ss_flags != TARGET_SS_ONSTACK && ss.ss_flags != 0) { goto out; } if (ss.ss_flags == TARGET_SS_DISABLE) { ss.ss_size = 0; ss.ss_sp = 0; } else { ret = -TARGET_ENOMEM; if (ss.ss_size < minstacksize) { goto out; } } ts->sigaltstack_used.ss_sp = ss.ss_sp; ts->sigaltstack_used.ss_size = ss.ss_size; } if (uoss_addr) { ret = -TARGET_EFAULT; if (copy_to_user(uoss_addr, &oss, sizeof(oss))) { goto out; } } ret = 0; out: return ret; } /* do_sigaction() return host values and errnos */ int do_sigaction(int sig, const struct target_sigaction *act, struct target_sigaction *oact) { struct target_sigaction *k; struct sigaction act1; int host_sig; int ret = 0; if (sig < 1 || sig > TARGET_NSIG) { return -TARGET_EINVAL; } if ((sig == TARGET_SIGKILL || sig == TARGET_SIGSTOP) && act != NULL && act->_sa_handler != TARGET_SIG_DFL) { return -TARGET_EINVAL; } if (block_signals()) { return -TARGET_ERESTART; } k = &sigact_table[sig - 1]; if (oact) { oact->_sa_handler = tswapal(k->_sa_handler); oact->sa_flags = tswap32(k->sa_flags); oact->sa_mask = k->sa_mask; } if (act) { k->_sa_handler = tswapal(act->_sa_handler); k->sa_flags = tswap32(act->sa_flags); k->sa_mask = act->sa_mask; /* Update the host signal state. */ host_sig = target_to_host_signal(sig); if (host_sig != SIGSEGV && host_sig != SIGBUS) { memset(&act1, 0, sizeof(struct sigaction)); sigfillset(&act1.sa_mask); act1.sa_flags = SA_SIGINFO; if (k->sa_flags & TARGET_SA_RESTART) { act1.sa_flags |= SA_RESTART; } /* * Note: It is important to update the host kernel signal mask to * avoid getting unexpected interrupted system calls. */ if (k->_sa_handler == TARGET_SIG_IGN) { act1.sa_sigaction = (void *)SIG_IGN; } else if (k->_sa_handler == TARGET_SIG_DFL) { if (fatal_signal(sig)) { act1.sa_sigaction = host_signal_handler; } else { act1.sa_sigaction = (void *)SIG_DFL; } } else { act1.sa_sigaction = host_signal_handler; } ret = sigaction(host_sig, &act1, NULL); } } return ret; } static inline abi_ulong get_sigframe(struct target_sigaction *ka, CPUArchState *env, size_t frame_size) { TaskState *ts = (TaskState *)thread_cpu->opaque; abi_ulong sp; /* Use default user stack */ sp = get_sp_from_cpustate(env); if ((ka->sa_flags & TARGET_SA_ONSTACK) && sas_ss_flags(ts, sp) == 0) { sp = ts->sigaltstack_used.ss_sp + ts->sigaltstack_used.ss_size; } /* TODO: make this a target_arch function / define */ #if defined(TARGET_ARM) return (sp - frame_size) & ~7; #elif defined(TARGET_AARCH64) return (sp - frame_size) & ~15; #else return sp - frame_size; #endif } /* compare to $M/$M/exec_machdep.c sendsig and sys/kern/kern_sig.c sigexit */ static void setup_frame(int sig, int code, struct target_sigaction *ka, target_sigset_t *set, target_siginfo_t *tinfo, CPUArchState *env) { struct target_sigframe *frame; abi_ulong frame_addr; int i; frame_addr = get_sigframe(ka, env, sizeof(*frame)); trace_user_setup_frame(env, frame_addr); if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) { unlock_user_struct(frame, frame_addr, 1); dump_core_and_abort(TARGET_SIGILL); return; } memset(frame, 0, sizeof(*frame)); setup_sigframe_arch(env, frame_addr, frame, 0); for (i = 0; i < TARGET_NSIG_WORDS; i++) { __put_user(set->__bits[i], &frame->sf_uc.uc_sigmask.__bits[i]); } if (tinfo) { frame->sf_si.si_signo = tinfo->si_signo; frame->sf_si.si_errno = tinfo->si_errno; frame->sf_si.si_code = tinfo->si_code; frame->sf_si.si_pid = tinfo->si_pid; frame->sf_si.si_uid = tinfo->si_uid; frame->sf_si.si_status = tinfo->si_status; frame->sf_si.si_addr = tinfo->si_addr; /* see host_to_target_siginfo_noswap() for more details */ frame->sf_si.si_value.sival_ptr = tinfo->si_value.sival_ptr; /* * At this point, whatever is in the _reason union is complete * and in target order, so just copy the whole thing over, even * if it's too large for this specific signal. * host_to_target_siginfo_noswap() and tswap_siginfo() have ensured * that's so. */ memcpy(&frame->sf_si._reason, &tinfo->_reason, sizeof(tinfo->_reason)); } set_sigtramp_args(env, sig, frame, frame_addr, ka); unlock_user_struct(frame, frame_addr, 1); } static int reset_signal_mask(target_ucontext_t *ucontext) { int i; sigset_t blocked; target_sigset_t target_set; TaskState *ts = (TaskState *)thread_cpu->opaque; for (i = 0; i < TARGET_NSIG_WORDS; i++) { __get_user(target_set.__bits[i], &ucontext->uc_sigmask.__bits[i]); } target_to_host_sigset_internal(&blocked, &target_set); ts->signal_mask = blocked; return 0; } /* See sys/$M/$M/exec_machdep.c sigreturn() */ long do_sigreturn(CPUArchState *env, abi_ulong addr) { long ret; abi_ulong target_ucontext; target_ucontext_t *ucontext = NULL; /* Get the target ucontext address from the stack frame */ ret = get_ucontext_sigreturn(env, addr, &target_ucontext); if (is_error(ret)) { return ret; } trace_user_do_sigreturn(env, addr); if (!lock_user_struct(VERIFY_READ, ucontext, target_ucontext, 0)) { goto badframe; } /* Set the register state back to before the signal. */ if (set_mcontext(env, &ucontext->uc_mcontext, 1)) { goto badframe; } /* And reset the signal mask. */ if (reset_signal_mask(ucontext)) { goto badframe; } unlock_user_struct(ucontext, target_ucontext, 0); return -TARGET_EJUSTRETURN; badframe: if (ucontext != NULL) { unlock_user_struct(ucontext, target_ucontext, 0); } return -TARGET_EFAULT; } void signal_init(void) { TaskState *ts = (TaskState *)thread_cpu->opaque; struct sigaction act; struct sigaction oact; int i; int host_sig; /* Set the signal mask from the host mask. */ sigprocmask(0, 0, &ts->signal_mask); sigfillset(&act.sa_mask); act.sa_sigaction = host_signal_handler; act.sa_flags = SA_SIGINFO; for (i = 1; i <= TARGET_NSIG; i++) { host_sig = target_to_host_signal(i); sigaction(host_sig, NULL, &oact); if (oact.sa_sigaction == (void *)SIG_IGN) { sigact_table[i - 1]._sa_handler = TARGET_SIG_IGN; } else if (oact.sa_sigaction == (void *)SIG_DFL) { sigact_table[i - 1]._sa_handler = TARGET_SIG_DFL; } /* * If there's already a handler installed then something has * gone horribly wrong, so don't even try to handle that case. * Install some handlers for our own use. We need at least * SIGSEGV and SIGBUS, to detect exceptions. We can not just * trap all signals because it affects syscall interrupt * behavior. But do trap all default-fatal signals. */ if (fatal_signal(i)) { sigaction(host_sig, &act, NULL); } } } static void handle_pending_signal(CPUArchState *env, int sig, struct emulated_sigtable *k) { CPUState *cpu = env_cpu(env); TaskState *ts = cpu->opaque; struct target_sigaction *sa; int code; sigset_t set; abi_ulong handler; target_siginfo_t tinfo; target_sigset_t target_old_set; trace_user_handle_signal(env, sig); k->pending = 0; sig = gdb_handlesig(cpu, sig); if (!sig) { sa = NULL; handler = TARGET_SIG_IGN; } else { sa = &sigact_table[sig - 1]; handler = sa->_sa_handler; } if (do_strace) { print_taken_signal(sig, &k->info); } if (handler == TARGET_SIG_DFL) { /* * default handler : ignore some signal. The other are job * control or fatal. */ if (sig == TARGET_SIGTSTP || sig == TARGET_SIGTTIN || sig == TARGET_SIGTTOU) { kill(getpid(), SIGSTOP); } else if (sig != TARGET_SIGCHLD && sig != TARGET_SIGURG && sig != TARGET_SIGINFO && sig != TARGET_SIGWINCH && sig != TARGET_SIGCONT) { dump_core_and_abort(sig); } } else if (handler == TARGET_SIG_IGN) { /* ignore sig */ } else if (handler == TARGET_SIG_ERR) { dump_core_and_abort(sig); } else { /* compute the blocked signals during the handler execution */ sigset_t *blocked_set; target_to_host_sigset(&set, &sa->sa_mask); /* * SA_NODEFER indicates that the current signal should not be * blocked during the handler. */ if (!(sa->sa_flags & TARGET_SA_NODEFER)) { sigaddset(&set, target_to_host_signal(sig)); } /* * Save the previous blocked signal state to restore it at the * end of the signal execution (see do_sigreturn). */ host_to_target_sigset_internal(&target_old_set, &ts->signal_mask); blocked_set = ts->in_sigsuspend ? &ts->sigsuspend_mask : &ts->signal_mask; sigorset(&ts->signal_mask, blocked_set, &set); ts->in_sigsuspend = false; sigprocmask(SIG_SETMASK, &ts->signal_mask, NULL); /* XXX VM86 on x86 ??? */ code = k->info.si_code; /* From host, so no si_type */ /* prepare the stack frame of the virtual CPU */ if (sa->sa_flags & TARGET_SA_SIGINFO) { tswap_siginfo(&tinfo, &k->info); setup_frame(sig, code, sa, &target_old_set, &tinfo, env); } else { setup_frame(sig, code, sa, &target_old_set, NULL, env); } if (sa->sa_flags & TARGET_SA_RESETHAND) { sa->_sa_handler = TARGET_SIG_DFL; } } } void process_pending_signals(CPUArchState *env) { CPUState *cpu = env_cpu(env); int sig; sigset_t *blocked_set, set; struct emulated_sigtable *k; TaskState *ts = cpu->opaque; while (qatomic_read(&ts->signal_pending)) { sigfillset(&set); sigprocmask(SIG_SETMASK, &set, 0); restart_scan: sig = ts->sync_signal.pending; if (sig) { /* * Synchronous signals are forced by the emulated CPU in some way. * If they are set to ignore, restore the default handler (see * sys/kern_sig.c trapsignal() and execsigs() for this behavior) * though maybe this is done only when forcing exit for non SIGCHLD. */ if (sigismember(&ts->signal_mask, target_to_host_signal(sig)) || sigact_table[sig - 1]._sa_handler == TARGET_SIG_IGN) { sigdelset(&ts->signal_mask, target_to_host_signal(sig)); sigact_table[sig - 1]._sa_handler = TARGET_SIG_DFL; } handle_pending_signal(env, sig, &ts->sync_signal); } k = ts->sigtab; for (sig = 1; sig <= TARGET_NSIG; sig++, k++) { blocked_set = ts->in_sigsuspend ? &ts->sigsuspend_mask : &ts->signal_mask; if (k->pending && !sigismember(blocked_set, target_to_host_signal(sig))) { handle_pending_signal(env, sig, k); /* * Restart scan from the beginning, as handle_pending_signal * might have resulted in a new synchronous signal (eg SIGSEGV). */ goto restart_scan; } } /* * Unblock signals and check one more time. Unblocking signals may cause * us to take another host signal, which will set signal_pending again. */ qatomic_set(&ts->signal_pending, 0); ts->in_sigsuspend = false; set = ts->signal_mask; sigdelset(&set, SIGSEGV); sigdelset(&set, SIGBUS); sigprocmask(SIG_SETMASK, &set, 0); } ts->in_sigsuspend = false; } void cpu_loop_exit_sigsegv(CPUState *cpu, target_ulong addr, MMUAccessType access_type, bool maperr, uintptr_t ra) { const TCGCPUOps *tcg_ops = CPU_GET_CLASS(cpu)->tcg_ops; if (tcg_ops->record_sigsegv) { tcg_ops->record_sigsegv(cpu, addr, access_type, maperr, ra); } force_sig_fault(TARGET_SIGSEGV, maperr ? TARGET_SEGV_MAPERR : TARGET_SEGV_ACCERR, addr); cpu->exception_index = EXCP_INTERRUPT; cpu_loop_exit_restore(cpu, ra); } void cpu_loop_exit_sigbus(CPUState *cpu, target_ulong addr, MMUAccessType access_type, uintptr_t ra) { const TCGCPUOps *tcg_ops = CPU_GET_CLASS(cpu)->tcg_ops; if (tcg_ops->record_sigbus) { tcg_ops->record_sigbus(cpu, addr, access_type, ra); } force_sig_fault(TARGET_SIGBUS, TARGET_BUS_ADRALN, addr); cpu->exception_index = EXCP_INTERRUPT; cpu_loop_exit_restore(cpu, ra); }