| /* |
| * 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 <http://www.gnu.org/licenses/>. |
| */ |
| |
| #include "qemu/osdep.h" |
| #include "qemu/log.h" |
| #include "qemu.h" |
| #include "exec/page-protection.h" |
| #include "user/tswap-target.h" |
| #include "gdbstub/user.h" |
| #include "signal-common.h" |
| #include "trace.h" |
| #include "hw/core/tcg-cpu-ops.h" |
| #include "host-signal.h" |
| |
| /* target_siginfo_t must fit in gdbstub's siginfo save area. */ |
| QEMU_BUILD_BUG_ON(sizeof(target_siginfo_t) > MAX_SIGINFO_LENGTH); |
| |
| 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 = get_task_state(thread_cpu); |
| 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 = get_task_state(cpu); |
| 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 |
| * -<signal>. 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 = get_task_state(cpu); |
| |
| 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; |
| target_siginfo_t info = {}; |
| |
| info.si_signo = sig; |
| info.si_errno = 0; |
| info.si_code = code; |
| info.si_addr = addr; |
| queue_signal(cpu_env(cpu), sig, QEMU_SI_FAULT, &info); |
| } |
| |
| static void host_signal_handler(int host_sig, siginfo_t *info, void *puc) |
| { |
| CPUState *cpu = thread_cpu; |
| TaskState *ts = get_task_state(cpu); |
| 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 = get_task_state(thread_cpu); |
| 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 = get_task_state(thread_cpu); |
| 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 = get_task_state(thread_cpu); |
| |
| 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 = get_task_state(thread_cpu); |
| 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 = get_task_state(cpu); |
| 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, NULL, &k->info, sizeof(k->info)); |
| 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 = get_task_state(cpu); |
| |
| 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); |
| } |
