1061 lines
34 KiB
C
1061 lines
34 KiB
C
/*
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* Emulation of Linux signals
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*
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* Copyright (c) 2003 Fabrice Bellard
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "qemu/osdep.h"
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#include "qemu/bitops.h"
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#include <sys/ucontext.h>
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#include <sys/resource.h>
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#include "qemu.h"
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#include "trace.h"
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#include "signal-common.h"
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static struct target_sigaction sigact_table[TARGET_NSIG];
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static void host_signal_handler(int host_signum, siginfo_t *info,
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void *puc);
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/*
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* System includes define _NSIG as SIGRTMAX + 1,
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* but qemu (like the kernel) defines TARGET_NSIG as TARGET_SIGRTMAX
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* and the first signal is SIGHUP defined as 1
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* Signal number 0 is reserved for use as kill(pid, 0), to test whether
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* a process exists without sending it a signal.
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*/
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QEMU_BUILD_BUG_ON(__SIGRTMAX + 1 != _NSIG);
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static uint8_t host_to_target_signal_table[_NSIG] = {
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[SIGHUP] = TARGET_SIGHUP,
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[SIGINT] = TARGET_SIGINT,
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[SIGQUIT] = TARGET_SIGQUIT,
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[SIGILL] = TARGET_SIGILL,
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[SIGTRAP] = TARGET_SIGTRAP,
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[SIGABRT] = TARGET_SIGABRT,
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/* [SIGIOT] = TARGET_SIGIOT,*/
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[SIGBUS] = TARGET_SIGBUS,
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[SIGFPE] = TARGET_SIGFPE,
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[SIGKILL] = TARGET_SIGKILL,
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[SIGUSR1] = TARGET_SIGUSR1,
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[SIGSEGV] = TARGET_SIGSEGV,
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[SIGUSR2] = TARGET_SIGUSR2,
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[SIGPIPE] = TARGET_SIGPIPE,
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[SIGALRM] = TARGET_SIGALRM,
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[SIGTERM] = TARGET_SIGTERM,
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#ifdef SIGSTKFLT
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[SIGSTKFLT] = TARGET_SIGSTKFLT,
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#endif
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[SIGCHLD] = TARGET_SIGCHLD,
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[SIGCONT] = TARGET_SIGCONT,
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[SIGSTOP] = TARGET_SIGSTOP,
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[SIGTSTP] = TARGET_SIGTSTP,
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[SIGTTIN] = TARGET_SIGTTIN,
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[SIGTTOU] = TARGET_SIGTTOU,
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[SIGURG] = TARGET_SIGURG,
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[SIGXCPU] = TARGET_SIGXCPU,
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[SIGXFSZ] = TARGET_SIGXFSZ,
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[SIGVTALRM] = TARGET_SIGVTALRM,
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[SIGPROF] = TARGET_SIGPROF,
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[SIGWINCH] = TARGET_SIGWINCH,
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[SIGIO] = TARGET_SIGIO,
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[SIGPWR] = TARGET_SIGPWR,
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[SIGSYS] = TARGET_SIGSYS,
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/* next signals stay the same */
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};
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static uint8_t target_to_host_signal_table[TARGET_NSIG + 1];
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/* valid sig is between 1 and _NSIG - 1 */
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int host_to_target_signal(int sig)
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{
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if (sig < 1 || sig >= _NSIG) {
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return sig;
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}
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return host_to_target_signal_table[sig];
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}
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/* valid sig is between 1 and TARGET_NSIG */
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int target_to_host_signal(int sig)
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{
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if (sig < 1 || sig > TARGET_NSIG) {
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return sig;
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}
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return target_to_host_signal_table[sig];
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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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abi_ulong mask = (abi_ulong)1 << (signum % TARGET_NSIG_BPW);
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set->sig[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->sig[signum / TARGET_NSIG_BPW] & mask) != 0);
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}
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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 host_sig, target_sig;
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target_sigemptyset(d);
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for (host_sig = 1; host_sig < _NSIG; host_sig++) {
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target_sig = host_to_target_signal(host_sig);
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if (target_sig < 1 || target_sig > TARGET_NSIG) {
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continue;
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}
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if (sigismember(s, host_sig)) {
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target_sigaddset(d, target_sig);
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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 < TARGET_NSIG_WORDS; i++)
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d->sig[i] = tswapal(d1.sig[i]);
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}
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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 host_sig, target_sig;
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sigemptyset(d);
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for (target_sig = 1; target_sig <= TARGET_NSIG; target_sig++) {
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host_sig = target_to_host_signal(target_sig);
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if (host_sig < 1 || host_sig >= _NSIG) {
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continue;
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}
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if (target_sigismember(s, target_sig)) {
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sigaddset(d, host_sig);
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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.sig[i] = tswapal(s->sig[i]);
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target_to_host_sigset_internal(d, &s1);
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}
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void host_to_target_old_sigset(abi_ulong *old_sigset,
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const sigset_t *sigset)
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{
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target_sigset_t d;
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host_to_target_sigset(&d, sigset);
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*old_sigset = d.sig[0];
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}
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void target_to_host_old_sigset(sigset_t *sigset,
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const abi_ulong *old_sigset)
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{
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target_sigset_t d;
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int i;
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d.sig[0] = *old_sigset;
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for(i = 1;i < TARGET_NSIG_WORDS; i++)
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d.sig[i] = 0;
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target_to_host_sigset(sigset, &d);
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}
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int block_signals(void)
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{
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TaskState *ts = (TaskState *)thread_cpu->opaque;
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sigset_t set;
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/* It's OK to block everything including SIGSEGV, because we won't
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* run any further guest code before unblocking signals in
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* process_pending_signals().
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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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/* Wrapper for sigprocmask function
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* Emulates a sigprocmask in a safe way for the guest. Note that set and oldset
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* are host signal set, not guest ones. Returns -TARGET_ERESTARTSYS if
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* a signal was already pending and the syscall must be restarted, or
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* 0 on success.
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* If set is NULL, this is guaranteed not to fail.
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*/
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int do_sigprocmask(int how, const sigset_t *set, sigset_t *oldset)
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{
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TaskState *ts = (TaskState *)thread_cpu->opaque;
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if (oldset) {
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*oldset = ts->signal_mask;
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}
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if (set) {
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int i;
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if (block_signals()) {
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return -TARGET_ERESTARTSYS;
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}
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switch (how) {
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case SIG_BLOCK:
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sigorset(&ts->signal_mask, &ts->signal_mask, set);
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break;
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case SIG_UNBLOCK:
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for (i = 1; i <= NSIG; ++i) {
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if (sigismember(set, i)) {
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sigdelset(&ts->signal_mask, i);
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}
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}
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break;
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case SIG_SETMASK:
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ts->signal_mask = *set;
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break;
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default:
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g_assert_not_reached();
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}
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/* Silently ignore attempts to change blocking status of KILL or STOP */
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sigdelset(&ts->signal_mask, SIGKILL);
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sigdelset(&ts->signal_mask, SIGSTOP);
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}
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return 0;
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}
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#if !defined(TARGET_NIOS2)
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/* Just set the guest's signal mask to the specified value; the
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* caller is assumed to have called block_signals() already.
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*/
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void set_sigmask(const sigset_t *set)
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{
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TaskState *ts = (TaskState *)thread_cpu->opaque;
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ts->signal_mask = *set;
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}
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#endif
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/* sigaltstack management */
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int on_sig_stack(unsigned long sp)
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{
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TaskState *ts = (TaskState *)thread_cpu->opaque;
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return (sp - ts->sigaltstack_used.ss_sp
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< ts->sigaltstack_used.ss_size);
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}
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int sas_ss_flags(unsigned long sp)
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{
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TaskState *ts = (TaskState *)thread_cpu->opaque;
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return (ts->sigaltstack_used.ss_size == 0 ? SS_DISABLE
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: on_sig_stack(sp) ? SS_ONSTACK : 0);
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}
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abi_ulong target_sigsp(abi_ulong sp, struct target_sigaction *ka)
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{
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/*
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* This is the X/Open sanctioned signal stack switching.
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*/
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TaskState *ts = (TaskState *)thread_cpu->opaque;
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if ((ka->sa_flags & TARGET_SA_ONSTACK) && !sas_ss_flags(sp)) {
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return ts->sigaltstack_used.ss_sp + ts->sigaltstack_used.ss_size;
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}
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return sp;
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}
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void target_save_altstack(target_stack_t *uss, CPUArchState *env)
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{
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TaskState *ts = (TaskState *)thread_cpu->opaque;
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__put_user(ts->sigaltstack_used.ss_sp, &uss->ss_sp);
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__put_user(sas_ss_flags(get_sp_from_cpustate(env)), &uss->ss_flags);
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__put_user(ts->sigaltstack_used.ss_size, &uss->ss_size);
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}
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/* siginfo conversion */
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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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tinfo->si_signo = sig;
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tinfo->si_errno = 0;
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tinfo->si_code = info->si_code;
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/* This memset serves two purposes:
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* (1) ensure we don't leak random junk to the guest later
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* (2) placate false positives from gcc about fields
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* being used uninitialized if it chooses to inline both this
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* function and tswap_siginfo() into host_to_target_siginfo().
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*/
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memset(tinfo->_sifields._pad, 0, sizeof(tinfo->_sifields._pad));
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/* This is awkward, because we have to use a combination of
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* the si_code and si_signo to figure out which of the union's
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* members are valid. (Within the host kernel it is always possible
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* to tell, but the kernel carefully avoids giving userspace the
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* high 16 bits of si_code, so we don't have the information to
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* do this the easy way...) We therefore make our best guess,
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* bearing in mind that a guest can spoof most of the si_codes
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* via rt_sigqueueinfo() if it likes.
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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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switch (si_code) {
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case SI_USER:
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case SI_TKILL:
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case SI_KERNEL:
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/* Sent via kill(), tkill() or tgkill(), or direct from the kernel.
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* These are the only unspoofable si_code values.
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*/
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tinfo->_sifields._kill._pid = info->si_pid;
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tinfo->_sifields._kill._uid = info->si_uid;
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si_type = QEMU_SI_KILL;
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break;
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default:
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/* Everything else is spoofable. Make best guess based on signal */
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switch (sig) {
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case TARGET_SIGCHLD:
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tinfo->_sifields._sigchld._pid = info->si_pid;
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tinfo->_sifields._sigchld._uid = info->si_uid;
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tinfo->_sifields._sigchld._status
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= host_to_target_waitstatus(info->si_status);
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tinfo->_sifields._sigchld._utime = info->si_utime;
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tinfo->_sifields._sigchld._stime = info->si_stime;
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si_type = QEMU_SI_CHLD;
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break;
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case TARGET_SIGIO:
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tinfo->_sifields._sigpoll._band = info->si_band;
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tinfo->_sifields._sigpoll._fd = info->si_fd;
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si_type = QEMU_SI_POLL;
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break;
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default:
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/* Assume a sigqueue()/mq_notify()/rt_sigqueueinfo() source. */
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tinfo->_sifields._rt._pid = info->si_pid;
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tinfo->_sifields._rt._uid = info->si_uid;
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/* XXX: potential problem if 64 bit */
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tinfo->_sifields._rt._sigval.sival_ptr
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= (abi_ulong)(unsigned long)info->si_value.sival_ptr;
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si_type = QEMU_SI_RT;
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break;
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}
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break;
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}
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tinfo->si_code = deposit32(si_code, 16, 16, si_type);
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}
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void tswap_siginfo(target_siginfo_t *tinfo,
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const target_siginfo_t *info)
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{
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int si_type = extract32(info->si_code, 16, 16);
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int si_code = sextract32(info->si_code, 0, 16);
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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);
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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_KILL:
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__put_user(info->_sifields._kill._pid, &tinfo->_sifields._kill._pid);
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__put_user(info->_sifields._kill._uid, &tinfo->_sifields._kill._uid);
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break;
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case QEMU_SI_TIMER:
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__put_user(info->_sifields._timer._timer1,
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&tinfo->_sifields._timer._timer1);
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__put_user(info->_sifields._timer._timer2,
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&tinfo->_sifields._timer._timer2);
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break;
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case QEMU_SI_POLL:
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__put_user(info->_sifields._sigpoll._band,
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&tinfo->_sifields._sigpoll._band);
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__put_user(info->_sifields._sigpoll._fd,
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&tinfo->_sifields._sigpoll._fd);
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break;
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case QEMU_SI_FAULT:
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__put_user(info->_sifields._sigfault._addr,
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&tinfo->_sifields._sigfault._addr);
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break;
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case QEMU_SI_CHLD:
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__put_user(info->_sifields._sigchld._pid,
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&tinfo->_sifields._sigchld._pid);
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__put_user(info->_sifields._sigchld._uid,
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&tinfo->_sifields._sigchld._uid);
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__put_user(info->_sifields._sigchld._status,
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&tinfo->_sifields._sigchld._status);
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__put_user(info->_sifields._sigchld._utime,
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&tinfo->_sifields._sigchld._utime);
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__put_user(info->_sifields._sigchld._stime,
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&tinfo->_sifields._sigchld._stime);
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break;
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case QEMU_SI_RT:
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__put_user(info->_sifields._rt._pid, &tinfo->_sifields._rt._pid);
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__put_user(info->_sifields._rt._uid, &tinfo->_sifields._rt._uid);
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__put_user(info->_sifields._rt._sigval.sival_ptr,
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&tinfo->_sifields._rt._sigval.sival_ptr);
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break;
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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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target_siginfo_t tgt_tmp;
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host_to_target_siginfo_noswap(&tgt_tmp, info);
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tswap_siginfo(tinfo, &tgt_tmp);
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}
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/* XXX: we support only POSIX RT signals are used. */
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/* XXX: find a solution for 64 bit (additional malloced data is needed) */
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void target_to_host_siginfo(siginfo_t *info, const target_siginfo_t *tinfo)
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{
|
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/* This conversion is used only for the rt_sigqueueinfo syscall,
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* and so we know that the _rt fields are the valid ones.
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*/
|
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abi_ulong sival_ptr;
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__get_user(info->si_signo, &tinfo->si_signo);
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__get_user(info->si_errno, &tinfo->si_errno);
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__get_user(info->si_code, &tinfo->si_code);
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__get_user(info->si_pid, &tinfo->_sifields._rt._pid);
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__get_user(info->si_uid, &tinfo->_sifields._rt._uid);
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__get_user(sival_ptr, &tinfo->_sifields._rt._sigval.sival_ptr);
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info->si_value.sival_ptr = (void *)(long)sival_ptr;
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}
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|
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static int fatal_signal (int sig)
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{
|
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switch (sig) {
|
|
case TARGET_SIGCHLD:
|
|
case TARGET_SIGURG:
|
|
case TARGET_SIGWINCH:
|
|
/* 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;
|
|
}
|
|
}
|
|
|
|
/* 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);
|
|
}
|
|
}
|
|
|
|
static void signal_table_init(void)
|
|
{
|
|
int host_sig, target_sig, count;
|
|
|
|
/*
|
|
* Signals are supported starting from TARGET_SIGRTMIN and going up
|
|
* until we run out of host realtime signals.
|
|
* glibc at least uses only the lower 2 rt signals and probably
|
|
* nobody's using the upper ones.
|
|
* it's why SIGRTMIN (34) is generally greater than __SIGRTMIN (32)
|
|
* To fix this properly we need to do manual signal delivery multiplexed
|
|
* over a single host signal.
|
|
* Attempts for configure "missing" signals via sigaction will be
|
|
* silently ignored.
|
|
*/
|
|
for (host_sig = SIGRTMIN; host_sig <= SIGRTMAX; host_sig++) {
|
|
target_sig = host_sig - SIGRTMIN + TARGET_SIGRTMIN;
|
|
if (target_sig <= TARGET_NSIG) {
|
|
host_to_target_signal_table[host_sig] = target_sig;
|
|
}
|
|
}
|
|
|
|
/* generate signal conversion tables */
|
|
for (target_sig = 1; target_sig <= TARGET_NSIG; target_sig++) {
|
|
target_to_host_signal_table[target_sig] = _NSIG; /* poison */
|
|
}
|
|
for (host_sig = 1; host_sig < _NSIG; host_sig++) {
|
|
if (host_to_target_signal_table[host_sig] == 0) {
|
|
host_to_target_signal_table[host_sig] = host_sig;
|
|
}
|
|
target_sig = host_to_target_signal_table[host_sig];
|
|
if (target_sig <= TARGET_NSIG) {
|
|
target_to_host_signal_table[target_sig] = host_sig;
|
|
}
|
|
}
|
|
|
|
if (trace_event_get_state_backends(TRACE_SIGNAL_TABLE_INIT)) {
|
|
for (target_sig = 1, count = 0; target_sig <= TARGET_NSIG; target_sig++) {
|
|
if (target_to_host_signal_table[target_sig] == _NSIG) {
|
|
count++;
|
|
}
|
|
}
|
|
trace_signal_table_init(count);
|
|
}
|
|
}
|
|
|
|
void signal_init(void)
|
|
{
|
|
TaskState *ts = (TaskState *)thread_cpu->opaque;
|
|
struct sigaction act;
|
|
struct sigaction oact;
|
|
int i;
|
|
int host_sig;
|
|
|
|
/* initialize signal conversion tables */
|
|
signal_table_init();
|
|
|
|
/* Set the signal mask from the host mask. */
|
|
sigprocmask(0, 0, &ts->signal_mask);
|
|
|
|
sigfillset(&act.sa_mask);
|
|
act.sa_flags = SA_SIGINFO;
|
|
act.sa_sigaction = host_signal_handler;
|
|
for(i = 1; i <= TARGET_NSIG; i++) {
|
|
#ifdef CONFIG_GPROF
|
|
if (i == TARGET_SIGPROF) {
|
|
continue;
|
|
}
|
|
#endif
|
|
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);
|
|
}
|
|
}
|
|
|
|
/* Force a synchronously taken signal. The kernel force_sig() function
|
|
* also forces the signal to "not blocked, not ignored", but for QEMU
|
|
* that work is done in process_pending_signals().
|
|
*/
|
|
void force_sig(int sig)
|
|
{
|
|
CPUState *cpu = thread_cpu;
|
|
CPUArchState *env = cpu->env_ptr;
|
|
target_siginfo_t info;
|
|
|
|
info.si_signo = sig;
|
|
info.si_errno = 0;
|
|
info.si_code = TARGET_SI_KERNEL;
|
|
info._sifields._kill._pid = 0;
|
|
info._sifields._kill._uid = 0;
|
|
queue_signal(env, info.si_signo, QEMU_SI_KILL, &info);
|
|
}
|
|
|
|
/* Force a SIGSEGV if we couldn't write to memory trying to set
|
|
* up the signal frame. oldsig is the signal we were trying to handle
|
|
* at the point of failure.
|
|
*/
|
|
#if !defined(TARGET_RISCV)
|
|
void force_sigsegv(int oldsig)
|
|
{
|
|
if (oldsig == SIGSEGV) {
|
|
/* Make sure we don't try to deliver the signal again; this will
|
|
* end up with handle_pending_signal() calling dump_core_and_abort().
|
|
*/
|
|
sigact_table[oldsig - 1]._sa_handler = TARGET_SIG_DFL;
|
|
}
|
|
force_sig(TARGET_SIGSEGV);
|
|
}
|
|
|
|
#endif
|
|
|
|
/* abort execution with signal */
|
|
static void QEMU_NORETURN dump_core_and_abort(int target_sig)
|
|
{
|
|
CPUState *cpu = thread_cpu;
|
|
CPUArchState *env = cpu->env_ptr;
|
|
TaskState *ts = (TaskState *)cpu->opaque;
|
|
int host_sig, core_dumped = 0;
|
|
struct sigaction act;
|
|
|
|
host_sig = target_to_host_signal(target_sig);
|
|
trace_user_force_sig(env, target_sig, host_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) {
|
|
/* we already dumped the core of target process, we don't want
|
|
* a coredump of qemu itself */
|
|
struct rlimit nodump;
|
|
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. */
|
|
sigfillset(&act.sa_mask);
|
|
act.sa_handler = SIG_DFL;
|
|
act.sa_flags = 0;
|
|
sigaction(host_sig, &act, NULL);
|
|
|
|
/* For some reason raise(host_sig) doesn't send the signal when
|
|
* statically linked on x86-64. */
|
|
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 */
|
|
int 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, 16, 16, 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 1; /* indicates that the signal was queued */
|
|
}
|
|
|
|
#ifndef HAVE_SAFE_SYSCALL
|
|
static inline void rewind_if_in_safe_syscall(void *puc)
|
|
{
|
|
/* Default version: never rewind */
|
|
}
|
|
#endif
|
|
|
|
static void host_signal_handler(int host_signum, siginfo_t *info,
|
|
void *puc)
|
|
{
|
|
CPUArchState *env = thread_cpu->env_ptr;
|
|
CPUState *cpu = env_cpu(env);
|
|
TaskState *ts = cpu->opaque;
|
|
|
|
int sig;
|
|
target_siginfo_t tinfo;
|
|
ucontext_t *uc = puc;
|
|
struct emulated_sigtable *k;
|
|
|
|
/* the CPU emulator uses some host signals to detect exceptions,
|
|
we forward to it some signals */
|
|
if ((host_signum == SIGSEGV || host_signum == SIGBUS)
|
|
&& info->si_code > 0) {
|
|
if (cpu_signal_handler(host_signum, info, puc))
|
|
return;
|
|
}
|
|
|
|
/* get target signal number */
|
|
sig = host_to_target_signal(host_signum);
|
|
if (sig < 1 || sig > TARGET_NSIG)
|
|
return;
|
|
trace_user_host_signal(env, host_signum, sig);
|
|
|
|
rewind_if_in_safe_syscall(puc);
|
|
|
|
host_to_target_siginfo_noswap(&tinfo, info);
|
|
k = &ts->sigtab[sig - 1];
|
|
k->info = tinfo;
|
|
k->pending = sig;
|
|
ts->signal_pending = 1;
|
|
|
|
/* 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().
|
|
*
|
|
* WARNING: we cannot use sigfillset() here because the uc_sigmask
|
|
* field is a kernel sigset_t, which is much smaller than the
|
|
* libc sigset_t which sigfillset() operates on. Using sigfillset()
|
|
* would write 0xff bytes off the end of the structure and trash
|
|
* data on the struct.
|
|
* We can't use sizeof(uc->uc_sigmask) either, because the libc
|
|
* headers define the struct field with the wrong (too large) type.
|
|
*/
|
|
memset(&uc->uc_sigmask, 0xff, SIGSET_T_SIZE);
|
|
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 linux/kernel/signal.c:do_sigaltstack() */
|
|
abi_long do_sigaltstack(abi_ulong uss_addr, abi_ulong uoss_addr, abi_ulong sp)
|
|
{
|
|
int ret;
|
|
struct target_sigaltstack oss;
|
|
TaskState *ts = (TaskState *)thread_cpu->opaque;
|
|
|
|
/* XXX: test errors */
|
|
if(uoss_addr)
|
|
{
|
|
__put_user(ts->sigaltstack_used.ss_sp, &oss.ss_sp);
|
|
__put_user(ts->sigaltstack_used.ss_size, &oss.ss_size);
|
|
__put_user(sas_ss_flags(sp), &oss.ss_flags);
|
|
}
|
|
|
|
if(uss_addr)
|
|
{
|
|
struct target_sigaltstack *uss;
|
|
struct target_sigaltstack ss;
|
|
size_t minstacksize = TARGET_MINSIGSTKSZ;
|
|
|
|
#if defined(TARGET_PPC64)
|
|
/* ELF V2 for PPC64 has a 4K minimum stack size for signal handlers */
|
|
struct image_info *image = ((TaskState *)thread_cpu->opaque)->info;
|
|
if (get_ppc64_abi(image) > 1) {
|
|
minstacksize = 4096;
|
|
}
|
|
#endif
|
|
|
|
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(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 target values and host 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;
|
|
|
|
trace_signal_do_sigaction_guest(sig, TARGET_NSIG);
|
|
|
|
if (sig < 1 || sig > TARGET_NSIG || sig == TARGET_SIGKILL || sig == TARGET_SIGSTOP) {
|
|
return -TARGET_EINVAL;
|
|
}
|
|
|
|
if (block_signals()) {
|
|
return -TARGET_ERESTARTSYS;
|
|
}
|
|
|
|
k = &sigact_table[sig - 1];
|
|
if (oact) {
|
|
__put_user(k->_sa_handler, &oact->_sa_handler);
|
|
__put_user(k->sa_flags, &oact->sa_flags);
|
|
#ifdef TARGET_ARCH_HAS_SA_RESTORER
|
|
__put_user(k->sa_restorer, &oact->sa_restorer);
|
|
#endif
|
|
/* Not swapped. */
|
|
oact->sa_mask = k->sa_mask;
|
|
}
|
|
if (act) {
|
|
/* FIXME: This is not threadsafe. */
|
|
__get_user(k->_sa_handler, &act->_sa_handler);
|
|
__get_user(k->sa_flags, &act->sa_flags);
|
|
#ifdef TARGET_ARCH_HAS_SA_RESTORER
|
|
__get_user(k->sa_restorer, &act->sa_restorer);
|
|
#endif
|
|
/* To be swapped in target_to_host_sigset. */
|
|
k->sa_mask = act->sa_mask;
|
|
|
|
/* we update the host linux signal state */
|
|
host_sig = target_to_host_signal(sig);
|
|
trace_signal_do_sigaction_host(host_sig, TARGET_NSIG);
|
|
if (host_sig > SIGRTMAX) {
|
|
/* we don't have enough host signals to map all target signals */
|
|
qemu_log_mask(LOG_UNIMP, "Unsupported target signal #%d, ignored\n",
|
|
sig);
|
|
/*
|
|
* we don't return an error here because some programs try to
|
|
* register an handler for all possible rt signals even if they
|
|
* don't need it.
|
|
* An error here can abort them whereas there can be no problem
|
|
* to not have the signal available later.
|
|
* This is the case for golang,
|
|
* See https://github.com/golang/go/issues/33746
|
|
* So we silently ignore the error.
|
|
*/
|
|
return 0;
|
|
}
|
|
if (host_sig != SIGSEGV && host_sig != SIGBUS) {
|
|
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
|
|
ignore state to avoid getting unexpected interrupted
|
|
syscalls */
|
|
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 void handle_pending_signal(CPUArchState *cpu_env, int sig,
|
|
struct emulated_sigtable *k)
|
|
{
|
|
CPUState *cpu = env_cpu(cpu_env);
|
|
abi_ulong handler;
|
|
sigset_t set;
|
|
target_sigset_t target_old_set;
|
|
struct target_sigaction *sa;
|
|
TaskState *ts = cpu->opaque;
|
|
|
|
trace_user_handle_signal(cpu_env, sig);
|
|
/* dequeue signal */
|
|
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 (unlikely(qemu_loglevel_mask(LOG_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_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);
|
|
|
|
/* block signals in the handler */
|
|
blocked_set = ts->in_sigsuspend ?
|
|
&ts->sigsuspend_mask : &ts->signal_mask;
|
|
sigorset(&ts->signal_mask, blocked_set, &set);
|
|
ts->in_sigsuspend = 0;
|
|
|
|
/* if the CPU is in VM86 mode, we restore the 32 bit values */
|
|
#if defined(TARGET_I386) && !defined(TARGET_X86_64)
|
|
{
|
|
CPUX86State *env = cpu_env;
|
|
if (env->eflags & VM_MASK)
|
|
save_v86_state(env);
|
|
}
|
|
#endif
|
|
/* prepare the stack frame of the virtual CPU */
|
|
#if defined(TARGET_ARCH_HAS_SETUP_FRAME)
|
|
if (sa->sa_flags & TARGET_SA_SIGINFO) {
|
|
setup_rt_frame(sig, sa, &k->info, &target_old_set, cpu_env);
|
|
} else {
|
|
setup_frame(sig, sa, &target_old_set, cpu_env);
|
|
}
|
|
#else
|
|
/* These targets do not have traditional signals. */
|
|
setup_rt_frame(sig, sa, &k->info, &target_old_set, cpu_env);
|
|
#endif
|
|
if (sa->sa_flags & TARGET_SA_RESETHAND) {
|
|
sa->_sa_handler = TARGET_SIG_DFL;
|
|
}
|
|
}
|
|
}
|
|
|
|
void process_pending_signals(CPUArchState *cpu_env)
|
|
{
|
|
CPUState *cpu = env_cpu(cpu_env);
|
|
int sig;
|
|
TaskState *ts = cpu->opaque;
|
|
sigset_t set;
|
|
sigset_t *blocked_set;
|
|
|
|
while (qatomic_read(&ts->signal_pending)) {
|
|
/* FIXME: This is not threadsafe. */
|
|
sigfillset(&set);
|
|
sigprocmask(SIG_SETMASK, &set, 0);
|
|
|
|
restart_scan:
|
|
sig = ts->sync_signal.pending;
|
|
if (sig) {
|
|
/* Synchronous signals are forced,
|
|
* see force_sig_info() and callers in Linux
|
|
* Note that not all of our queue_signal() calls in QEMU correspond
|
|
* to force_sig_info() calls in Linux (some are send_sig_info()).
|
|
* However it seems like a kernel bug to me to allow the process
|
|
* to block a synchronous signal since it could then just end up
|
|
* looping round and round indefinitely.
|
|
*/
|
|
if (sigismember(&ts->signal_mask, target_to_host_signal_table[sig])
|
|
|| sigact_table[sig - 1]._sa_handler == TARGET_SIG_IGN) {
|
|
sigdelset(&ts->signal_mask, target_to_host_signal_table[sig]);
|
|
sigact_table[sig - 1]._sa_handler = TARGET_SIG_DFL;
|
|
}
|
|
|
|
handle_pending_signal(cpu_env, sig, &ts->sync_signal);
|
|
}
|
|
|
|
for (sig = 1; sig <= TARGET_NSIG; sig++) {
|
|
blocked_set = ts->in_sigsuspend ?
|
|
&ts->sigsuspend_mask : &ts->signal_mask;
|
|
|
|
if (ts->sigtab[sig - 1].pending &&
|
|
(!sigismember(blocked_set,
|
|
target_to_host_signal_table[sig]))) {
|
|
handle_pending_signal(cpu_env, sig, &ts->sigtab[sig - 1]);
|
|
/* Restart scan from the beginning, as handle_pending_signal
|
|
* might have resulted in a new synchronous signal (eg SIGSEGV).
|
|
*/
|
|
goto restart_scan;
|
|
}
|
|
}
|
|
|
|
/* if no signal is pending, unblock signals and recheck (the act
|
|
* of unblocking might cause us to take another host signal which
|
|
* will set signal_pending again).
|
|
*/
|
|
qatomic_set(&ts->signal_pending, 0);
|
|
ts->in_sigsuspend = 0;
|
|
set = ts->signal_mask;
|
|
sigdelset(&set, SIGSEGV);
|
|
sigdelset(&set, SIGBUS);
|
|
sigprocmask(SIG_SETMASK, &set, 0);
|
|
}
|
|
ts->in_sigsuspend = 0;
|
|
}
|