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https://gitlab.com/qemu-project/qemu.git
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5fa2a10ba6
Most (all?) targets require stacks to be properly aligned. Rather than a series of ifdefs in bsd-user/signal.h, instead use a manditory #define for all architectures. Signed-off-by: Warner Losh <imp@bsdimp.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
1048 lines
32 KiB
C
1048 lines
32 KiB
C
/*
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* Emulation of BSD signals
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*
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* Copyright (c) 2003 - 2008 Fabrice Bellard
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* Copyright (c) 2013 Stacey Son
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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 "qemu/osdep.h"
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#include "qemu/log.h"
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#include "qemu.h"
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#include "exec/page-protection.h"
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#include "user/tswap-target.h"
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#include "gdbstub/user.h"
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#include "signal-common.h"
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#include "trace.h"
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#include "hw/core/tcg-cpu-ops.h"
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#include "host-signal.h"
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/* target_siginfo_t must fit in gdbstub's siginfo save area. */
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QEMU_BUILD_BUG_ON(sizeof(target_siginfo_t) > MAX_SIGINFO_LENGTH);
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static struct target_sigaction sigact_table[TARGET_NSIG];
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static void host_signal_handler(int host_sig, siginfo_t *info, void *puc);
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static void target_to_host_sigset_internal(sigset_t *d,
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const target_sigset_t *s);
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static inline int on_sig_stack(TaskState *ts, unsigned long sp)
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{
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return sp - ts->sigaltstack_used.ss_sp < ts->sigaltstack_used.ss_size;
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}
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static inline int sas_ss_flags(TaskState *ts, unsigned long sp)
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{
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return ts->sigaltstack_used.ss_size == 0 ? SS_DISABLE :
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on_sig_stack(ts, sp) ? SS_ONSTACK : 0;
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}
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/*
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* The BSD ABIs use the same signal numbers across all the CPU architectures, so
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* (unlike Linux) these functions are just the identity mapping. This might not
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* be true for XyzBSD running on AbcBSD, which doesn't currently work.
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*/
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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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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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static inline void target_sigemptyset(target_sigset_t *set)
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{
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memset(set, 0, sizeof(*set));
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}
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static inline void target_sigaddset(target_sigset_t *set, int signum)
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{
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signum--;
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uint32_t mask = (uint32_t)1 << (signum % TARGET_NSIG_BPW);
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set->__bits[signum / TARGET_NSIG_BPW] |= mask;
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}
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static inline int target_sigismember(const target_sigset_t *set, int signum)
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{
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signum--;
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abi_ulong mask = (abi_ulong)1 << (signum % TARGET_NSIG_BPW);
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return (set->__bits[signum / TARGET_NSIG_BPW] & mask) != 0;
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}
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/* Adjust the signal context to rewind out of safe-syscall if we're in it */
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static inline void rewind_if_in_safe_syscall(void *puc)
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{
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ucontext_t *uc = (ucontext_t *)puc;
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uintptr_t pcreg = host_signal_pc(uc);
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if (pcreg > (uintptr_t)safe_syscall_start
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&& pcreg < (uintptr_t)safe_syscall_end) {
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host_signal_set_pc(uc, (uintptr_t)safe_syscall_start);
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}
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}
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/*
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* Note: The following take advantage of the BSD signal property that all
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* signals are available on all architectures.
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*/
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static void host_to_target_sigset_internal(target_sigset_t *d,
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const sigset_t *s)
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{
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int i;
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target_sigemptyset(d);
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for (i = 1; i <= NSIG; i++) {
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if (sigismember(s, i)) {
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target_sigaddset(d, host_to_target_signal(i));
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}
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}
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}
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void host_to_target_sigset(target_sigset_t *d, const sigset_t *s)
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{
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target_sigset_t d1;
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int i;
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host_to_target_sigset_internal(&d1, s);
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for (i = 0; i < _SIG_WORDS; i++) {
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d->__bits[i] = tswap32(d1.__bits[i]);
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}
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}
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static void target_to_host_sigset_internal(sigset_t *d,
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const target_sigset_t *s)
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{
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int i;
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sigemptyset(d);
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for (i = 1; i <= TARGET_NSIG; i++) {
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if (target_sigismember(s, i)) {
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sigaddset(d, target_to_host_signal(i));
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}
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}
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}
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void target_to_host_sigset(sigset_t *d, const target_sigset_t *s)
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{
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target_sigset_t s1;
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int i;
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for (i = 0; i < TARGET_NSIG_WORDS; i++) {
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s1.__bits[i] = tswap32(s->__bits[i]);
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}
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target_to_host_sigset_internal(d, &s1);
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}
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static bool has_trapno(int tsig)
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{
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return tsig == TARGET_SIGILL ||
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tsig == TARGET_SIGFPE ||
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tsig == TARGET_SIGSEGV ||
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tsig == TARGET_SIGBUS ||
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tsig == TARGET_SIGTRAP;
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}
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/* Siginfo conversion. */
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/*
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* Populate tinfo w/o swapping based on guessing which fields are valid.
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*/
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static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo,
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const siginfo_t *info)
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{
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int sig = host_to_target_signal(info->si_signo);
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int si_code = info->si_code;
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int si_type;
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/*
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* Make sure we that the variable portion of the target siginfo is zeroed
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* out so we don't leak anything into that.
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*/
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memset(&tinfo->_reason, 0, sizeof(tinfo->_reason));
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/*
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* This is awkward, because we have to use a combination of the si_code and
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* si_signo to figure out which of the union's members are valid.o We
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* therefore make our best guess.
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*
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* Once we have made our guess, we record it in the top 16 bits of
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* the si_code, so that tswap_siginfo() later can use it.
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* tswap_siginfo() will strip these top bits out before writing
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* si_code to the guest (sign-extending the lower bits).
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*/
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tinfo->si_signo = sig;
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tinfo->si_errno = info->si_errno;
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tinfo->si_code = info->si_code;
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tinfo->si_pid = info->si_pid;
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tinfo->si_uid = info->si_uid;
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tinfo->si_status = info->si_status;
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tinfo->si_addr = (abi_ulong)(unsigned long)info->si_addr;
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/*
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* si_value is opaque to kernel. On all FreeBSD platforms,
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* sizeof(sival_ptr) >= sizeof(sival_int) so the following
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* always will copy the larger element.
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*/
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tinfo->si_value.sival_ptr =
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(abi_ulong)(unsigned long)info->si_value.sival_ptr;
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switch (si_code) {
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/*
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* All the SI_xxx codes that are defined here are global to
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* all the signals (they have values that none of the other,
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* more specific signal info will set).
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*/
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case SI_USER:
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case SI_LWP:
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case SI_KERNEL:
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case SI_QUEUE:
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case SI_ASYNCIO:
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/*
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* Only the fixed parts are valid (though FreeBSD doesn't always
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* set all the fields to non-zero values.
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*/
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si_type = QEMU_SI_NOINFO;
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break;
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case SI_TIMER:
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tinfo->_reason._timer._timerid = info->_reason._timer._timerid;
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tinfo->_reason._timer._overrun = info->_reason._timer._overrun;
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si_type = QEMU_SI_TIMER;
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break;
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case SI_MESGQ:
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tinfo->_reason._mesgq._mqd = info->_reason._mesgq._mqd;
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si_type = QEMU_SI_MESGQ;
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break;
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default:
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/*
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* We have to go based on the signal number now to figure out
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* what's valid.
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*/
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si_type = QEMU_SI_NOINFO;
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if (has_trapno(sig)) {
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tinfo->_reason._fault._trapno = info->_reason._fault._trapno;
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si_type = QEMU_SI_FAULT;
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}
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#ifdef TARGET_SIGPOLL
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/*
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* FreeBSD never had SIGPOLL, but emulates it for Linux so there's
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* a chance it may popup in the future.
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*/
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if (sig == TARGET_SIGPOLL) {
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tinfo->_reason._poll._band = info->_reason._poll._band;
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si_type = QEMU_SI_POLL;
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}
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#endif
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/*
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* Unsure that this can actually be generated, and our support for
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* capsicum is somewhere between weak and non-existent, but if we get
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* one, then we know what to save.
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*/
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#ifdef QEMU_SI_CAPSICUM
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if (sig == TARGET_SIGTRAP) {
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tinfo->_reason._capsicum._syscall =
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info->_reason._capsicum._syscall;
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si_type = QEMU_SI_CAPSICUM;
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}
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#endif
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break;
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}
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tinfo->si_code = deposit32(si_code, 24, 8, si_type);
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}
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static void tswap_siginfo(target_siginfo_t *tinfo, const target_siginfo_t *info)
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{
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int si_type = extract32(info->si_code, 24, 8);
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int si_code = sextract32(info->si_code, 0, 24);
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__put_user(info->si_signo, &tinfo->si_signo);
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__put_user(info->si_errno, &tinfo->si_errno);
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__put_user(si_code, &tinfo->si_code); /* Zero out si_type, it's internal */
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__put_user(info->si_pid, &tinfo->si_pid);
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__put_user(info->si_uid, &tinfo->si_uid);
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__put_user(info->si_status, &tinfo->si_status);
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__put_user(info->si_addr, &tinfo->si_addr);
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/*
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* Unswapped, because we passed it through mostly untouched. si_value is
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* opaque to the kernel, so we didn't bother with potentially wasting cycles
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* to swap it into host byte order.
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*/
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tinfo->si_value.sival_ptr = info->si_value.sival_ptr;
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/*
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* We can use our internal marker of which fields in the structure
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* are valid, rather than duplicating the guesswork of
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* host_to_target_siginfo_noswap() here.
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*/
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switch (si_type) {
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case QEMU_SI_NOINFO: /* No additional info */
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break;
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case QEMU_SI_FAULT:
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__put_user(info->_reason._fault._trapno,
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&tinfo->_reason._fault._trapno);
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break;
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case QEMU_SI_TIMER:
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__put_user(info->_reason._timer._timerid,
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&tinfo->_reason._timer._timerid);
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__put_user(info->_reason._timer._overrun,
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&tinfo->_reason._timer._overrun);
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break;
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case QEMU_SI_MESGQ:
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__put_user(info->_reason._mesgq._mqd, &tinfo->_reason._mesgq._mqd);
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break;
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case QEMU_SI_POLL:
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/* Note: Not generated on FreeBSD */
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__put_user(info->_reason._poll._band, &tinfo->_reason._poll._band);
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break;
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#ifdef QEMU_SI_CAPSICUM
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case QEMU_SI_CAPSICUM:
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__put_user(info->_reason._capsicum._syscall,
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&tinfo->_reason._capsicum._syscall);
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break;
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#endif
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default:
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g_assert_not_reached();
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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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host_to_target_siginfo_noswap(tinfo, info);
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tswap_siginfo(tinfo, tinfo);
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}
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int block_signals(void)
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{
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TaskState *ts = get_task_state(thread_cpu);
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sigset_t set;
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/*
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* It's OK to block everything including SIGSEGV, because we won't run any
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* further guest code before unblocking signals in
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* process_pending_signals(). We depend on the FreeBSD behavior here where
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* this will only affect this thread's signal mask. We don't use
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* pthread_sigmask which might seem more correct because that routine also
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* does odd things with SIGCANCEL to implement pthread_cancel().
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*/
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sigfillset(&set);
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sigprocmask(SIG_SETMASK, &set, 0);
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return qatomic_xchg(&ts->signal_pending, 1);
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}
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/* Returns 1 if given signal should dump core if not handled. */
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static int core_dump_signal(int sig)
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{
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switch (sig) {
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case TARGET_SIGABRT:
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case TARGET_SIGFPE:
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case TARGET_SIGILL:
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case TARGET_SIGQUIT:
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case TARGET_SIGSEGV:
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case TARGET_SIGTRAP:
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case TARGET_SIGBUS:
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return 1;
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default:
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return 0;
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}
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}
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/* Abort execution with signal. */
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static G_NORETURN
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void dump_core_and_abort(int target_sig)
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{
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CPUState *cpu = thread_cpu;
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CPUArchState *env = cpu_env(cpu);
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TaskState *ts = get_task_state(cpu);
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int core_dumped = 0;
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int host_sig;
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struct sigaction act;
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host_sig = target_to_host_signal(target_sig);
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gdb_signalled(env, target_sig);
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/* Dump core if supported by target binary format */
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if (core_dump_signal(target_sig) && (ts->bprm->core_dump != NULL)) {
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stop_all_tasks();
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core_dumped =
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((*ts->bprm->core_dump)(target_sig, env) == 0);
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}
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if (core_dumped) {
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struct rlimit nodump;
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/*
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* We already dumped the core of target process, we don't want
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* a coredump of qemu itself.
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*/
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getrlimit(RLIMIT_CORE, &nodump);
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nodump.rlim_cur = 0;
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setrlimit(RLIMIT_CORE, &nodump);
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(void) fprintf(stderr, "qemu: uncaught target signal %d (%s) "
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"- %s\n", target_sig, strsignal(host_sig), "core dumped");
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}
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/*
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* The proper exit code for dying from an uncaught signal is
|
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* -<signal>. The kernel doesn't allow exit() or _exit() to pass
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* a negative value. To get the proper exit code we need to
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* actually die from an uncaught signal. Here the default signal
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* handler is installed, we send ourself a signal and we wait for
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* it to arrive.
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*/
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memset(&act, 0, sizeof(act));
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sigfillset(&act.sa_mask);
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act.sa_handler = SIG_DFL;
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sigaction(host_sig, &act, NULL);
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kill(getpid(), host_sig);
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/*
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* Make sure the signal isn't masked (just reuse the mask inside
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* of act).
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*/
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sigdelset(&act.sa_mask, host_sig);
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sigsuspend(&act.sa_mask);
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/* unreachable */
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abort();
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}
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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 as
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* possible.
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*/
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void queue_signal(CPUArchState *env, int sig, int si_type,
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target_siginfo_t *info)
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{
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CPUState *cpu = env_cpu(env);
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TaskState *ts = get_task_state(cpu);
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trace_user_queue_signal(env, sig);
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info->si_code = deposit32(info->si_code, 24, 8, si_type);
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ts->sync_signal.info = *info;
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ts->sync_signal.pending = sig;
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/* Signal that a new signal is pending. */
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qatomic_set(&ts->signal_pending, 1);
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return;
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}
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static int fatal_signal(int sig)
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{
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|
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switch (sig) {
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case TARGET_SIGCHLD:
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case TARGET_SIGURG:
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case TARGET_SIGWINCH:
|
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case TARGET_SIGINFO:
|
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/* Ignored by default. */
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return 0;
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case TARGET_SIGCONT:
|
|
case TARGET_SIGSTOP:
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case TARGET_SIGTSTP:
|
|
case TARGET_SIGTTIN:
|
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case TARGET_SIGTTOU:
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/* Job control signals. */
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return 0;
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default:
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return 1;
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}
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}
|
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|
|
/*
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|
* Force a synchronously taken QEMU_SI_FAULT signal. For QEMU the
|
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* 'force' part is handled in process_pending_signals().
|
|
*/
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void force_sig_fault(int sig, int code, abi_ulong addr)
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{
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CPUState *cpu = thread_cpu;
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target_siginfo_t info = {};
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info.si_signo = sig;
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info.si_errno = 0;
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info.si_code = code;
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info.si_addr = addr;
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queue_signal(cpu_env(cpu), sig, QEMU_SI_FAULT, &info);
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}
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|
|
static void host_signal_handler(int host_sig, siginfo_t *info, void *puc)
|
|
{
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CPUState *cpu = thread_cpu;
|
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TaskState *ts = get_task_state(cpu);
|
|
target_siginfo_t tinfo;
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ucontext_t *uc = puc;
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struct emulated_sigtable *k;
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|
int guest_sig;
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uintptr_t pc = 0;
|
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bool sync_sig = false;
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|
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/*
|
|
* 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;
|
|
}
|
|
|
|
return ROUND_DOWN(sp - frame_size, TARGET_SIGSTACK_ALIGN);
|
|
}
|
|
|
|
/* 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);
|
|
}
|