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qemu / qemu / d5e2f3d03c38db716b3f18927626facc8233830c / . / bsd-user / signal.c
blob: e5a773dddeeffb375ce08ac7ede4c8e5aca00871 [file] [log] [blame]
/*
* Emulation of BSD signals
*
* Copyright (c) 2003 - 2008 Fabrice Bellard
* Copyright (c) 2013 Stacey Son
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qemu/log.h"
#include "qemu.h"
#include "gdbstub/user.h"
#include "signal-common.h"
#include "trace.h"
#include "hw/core/tcg-cpu-ops.h"
#include "host-signal.h"
/* target_siginfo_t must fit in gdbstub's siginfo save area. */
QEMU_BUILD_BUG_ON(sizeof(target_siginfo_t) > MAX_SIGINFO_LENGTH);
static struct target_sigaction sigact_table[TARGET_NSIG];
static void host_signal_handler(int host_sig, siginfo_t *info, void *puc);
static void target_to_host_sigset_internal(sigset_t *d,
const target_sigset_t *s);
static inline int on_sig_stack(TaskState *ts, unsigned long sp)
{
return sp - ts->sigaltstack_used.ss_sp < ts->sigaltstack_used.ss_size;
}
static inline int sas_ss_flags(TaskState *ts, unsigned long sp)
{
return ts->sigaltstack_used.ss_size == 0 ? SS_DISABLE :
on_sig_stack(ts, sp) ? SS_ONSTACK : 0;
}
/*
* The BSD ABIs use the same signal numbers across all the CPU architectures, so
* (unlike Linux) these functions are just the identity mapping. This might not
* be true for XyzBSD running on AbcBSD, which doesn't currently work.
*/
int host_to_target_signal(int sig)
{
return sig;
}
int target_to_host_signal(int sig)
{
return sig;
}
static inline void target_sigemptyset(target_sigset_t *set)
{
memset(set, 0, sizeof(*set));
}
static inline void target_sigaddset(target_sigset_t *set, int signum)
{
signum--;
uint32_t mask = (uint32_t)1 << (signum % TARGET_NSIG_BPW);
set->__bits[signum / TARGET_NSIG_BPW] |= mask;
}
static inline int target_sigismember(const target_sigset_t *set, int signum)
{
signum--;
abi_ulong mask = (abi_ulong)1 << (signum % TARGET_NSIG_BPW);
return (set->__bits[signum / TARGET_NSIG_BPW] & mask) != 0;
}
/* Adjust the signal context to rewind out of safe-syscall if we're in it */
static inline void rewind_if_in_safe_syscall(void *puc)
{
ucontext_t *uc = (ucontext_t *)puc;
uintptr_t pcreg = host_signal_pc(uc);
if (pcreg > (uintptr_t)safe_syscall_start
&& pcreg < (uintptr_t)safe_syscall_end) {
host_signal_set_pc(uc, (uintptr_t)safe_syscall_start);
}
}
/*
* Note: The following take advantage of the BSD signal property that all
* signals are available on all architectures.
*/
static void host_to_target_sigset_internal(target_sigset_t *d,
const sigset_t *s)
{
int i;
target_sigemptyset(d);
for (i = 1; i <= NSIG; i++) {
if (sigismember(s, i)) {
target_sigaddset(d, host_to_target_signal(i));
}
}
}
void host_to_target_sigset(target_sigset_t *d, const sigset_t *s)
{
target_sigset_t d1;
int i;
host_to_target_sigset_internal(&d1, s);
for (i = 0; i < _SIG_WORDS; i++) {
d->__bits[i] = tswap32(d1.__bits[i]);
}
}
static void target_to_host_sigset_internal(sigset_t *d,
const target_sigset_t *s)
{
int i;
sigemptyset(d);
for (i = 1; i <= TARGET_NSIG; i++) {
if (target_sigismember(s, i)) {
sigaddset(d, target_to_host_signal(i));
}
}
}
void target_to_host_sigset(sigset_t *d, const target_sigset_t *s)
{
target_sigset_t s1;
int i;
for (i = 0; i < TARGET_NSIG_WORDS; i++) {
s1.__bits[i] = tswap32(s->__bits[i]);
}
target_to_host_sigset_internal(d, &s1);
}
static bool has_trapno(int tsig)
{
return tsig == TARGET_SIGILL ||
tsig == TARGET_SIGFPE ||
tsig == TARGET_SIGSEGV ||
tsig == TARGET_SIGBUS ||
tsig == TARGET_SIGTRAP;
}
/* Siginfo conversion. */
/*
* Populate tinfo w/o swapping based on guessing which fields are valid.
*/
static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo,
const siginfo_t *info)
{
int sig = host_to_target_signal(info->si_signo);
int si_code = info->si_code;
int si_type;
/*
* Make sure we that the variable portion of the target siginfo is zeroed
* out so we don't leak anything into that.
*/
memset(&tinfo->_reason, 0, sizeof(tinfo->_reason));
/*
* This is awkward, because we have to use a combination of the si_code and
* si_signo to figure out which of the union's members are valid.o We
* therefore make our best guess.
*
* Once we have made our guess, we record it in the top 16 bits of
* the si_code, so that tswap_siginfo() later can use it.
* tswap_siginfo() will strip these top bits out before writing
* si_code to the guest (sign-extending the lower bits).
*/
tinfo->si_signo = sig;
tinfo->si_errno = info->si_errno;
tinfo->si_code = info->si_code;
tinfo->si_pid = info->si_pid;
tinfo->si_uid = info->si_uid;
tinfo->si_status = info->si_status;
tinfo->si_addr = (abi_ulong)(unsigned long)info->si_addr;
/*
* si_value is opaque to kernel. On all FreeBSD platforms,
* sizeof(sival_ptr) >= sizeof(sival_int) so the following
* always will copy the larger element.
*/
tinfo->si_value.sival_ptr =
(abi_ulong)(unsigned long)info->si_value.sival_ptr;
switch (si_code) {
/*
* All the SI_xxx codes that are defined here are global to
* all the signals (they have values that none of the other,
* more specific signal info will set).
*/
case SI_USER:
case SI_LWP:
case SI_KERNEL:
case SI_QUEUE:
case SI_ASYNCIO:
/*
* Only the fixed parts are valid (though FreeBSD doesn't always
* set all the fields to non-zero values.
*/
si_type = QEMU_SI_NOINFO;
break;
case SI_TIMER:
tinfo->_reason._timer._timerid = info->_reason._timer._timerid;
tinfo->_reason._timer._overrun = info->_reason._timer._overrun;
si_type = QEMU_SI_TIMER;
break;
case SI_MESGQ:
tinfo->_reason._mesgq._mqd = info->_reason._mesgq._mqd;
si_type = QEMU_SI_MESGQ;
break;
default:
/*
* We have to go based on the signal number now to figure out
* what's valid.
*/
si_type = QEMU_SI_NOINFO;
if (has_trapno(sig)) {
tinfo->_reason._fault._trapno = info->_reason._fault._trapno;
si_type = QEMU_SI_FAULT;
}
#ifdef TARGET_SIGPOLL
/*
* FreeBSD never had SIGPOLL, but emulates it for Linux so there's
* a chance it may popup in the future.
*/
if (sig == TARGET_SIGPOLL) {
tinfo->_reason._poll._band = info->_reason._poll._band;
si_type = QEMU_SI_POLL;
}
#endif
/*
* Unsure that this can actually be generated, and our support for
* capsicum is somewhere between weak and non-existent, but if we get
* one, then we know what to save.
*/
#ifdef QEMU_SI_CAPSICUM
if (sig == TARGET_SIGTRAP) {
tinfo->_reason._capsicum._syscall =
info->_reason._capsicum._syscall;
si_type = QEMU_SI_CAPSICUM;
}
#endif
break;
}
tinfo->si_code = deposit32(si_code, 24, 8, si_type);
}
static void tswap_siginfo(target_siginfo_t *tinfo, const target_siginfo_t *info)
{
int si_type = extract32(info->si_code, 24, 8);
int si_code = sextract32(info->si_code, 0, 24);
__put_user(info->si_signo, &tinfo->si_signo);
__put_user(info->si_errno, &tinfo->si_errno);
__put_user(si_code, &tinfo->si_code); /* Zero out si_type, it's internal */
__put_user(info->si_pid, &tinfo->si_pid);
__put_user(info->si_uid, &tinfo->si_uid);
__put_user(info->si_status, &tinfo->si_status);
__put_user(info->si_addr, &tinfo->si_addr);
/*
* Unswapped, because we passed it through mostly untouched. si_value is
* opaque to the kernel, so we didn't bother with potentially wasting cycles
* to swap it into host byte order.
*/
tinfo->si_value.sival_ptr = info->si_value.sival_ptr;
/*
* We can use our internal marker of which fields in the structure
* are valid, rather than duplicating the guesswork of
* host_to_target_siginfo_noswap() here.
*/
switch (si_type) {
case QEMU_SI_NOINFO: /* No additional info */
break;
case QEMU_SI_FAULT:
__put_user(info->_reason._fault._trapno,
&tinfo->_reason._fault._trapno);
break;
case QEMU_SI_TIMER:
__put_user(info->_reason._timer._timerid,
&tinfo->_reason._timer._timerid);
__put_user(info->_reason._timer._overrun,
&tinfo->_reason._timer._overrun);
break;
case QEMU_SI_MESGQ:
__put_user(info->_reason._mesgq._mqd, &tinfo->_reason._mesgq._mqd);
break;
case QEMU_SI_POLL:
/* Note: Not generated on FreeBSD */
__put_user(info->_reason._poll._band, &tinfo->_reason._poll._band);
break;
#ifdef QEMU_SI_CAPSICUM
case QEMU_SI_CAPSICUM:
__put_user(info->_reason._capsicum._syscall,
&tinfo->_reason._capsicum._syscall);
break;
#endif
default:
g_assert_not_reached();
}
}
void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info)
{
host_to_target_siginfo_noswap(tinfo, info);
tswap_siginfo(tinfo, tinfo);
}
int block_signals(void)
{
TaskState *ts = get_task_state(thread_cpu);
sigset_t set;
/*
* It's OK to block everything including SIGSEGV, because we won't run any
* further guest code before unblocking signals in
* process_pending_signals(). We depend on the FreeBSD behavior here where
* this will only affect this thread's signal mask. We don't use
* pthread_sigmask which might seem more correct because that routine also
* does odd things with SIGCANCEL to implement pthread_cancel().
*/
sigfillset(&set);
sigprocmask(SIG_SETMASK, &set, 0);
return qatomic_xchg(&ts->signal_pending, 1);
}
/* Returns 1 if given signal should dump core if not handled. */
static int core_dump_signal(int sig)
{
switch (sig) {
case TARGET_SIGABRT:
case TARGET_SIGFPE:
case TARGET_SIGILL:
case TARGET_SIGQUIT:
case TARGET_SIGSEGV:
case TARGET_SIGTRAP:
case TARGET_SIGBUS:
return 1;
default:
return 0;
}
}
/* Abort execution with signal. */
static G_NORETURN
void dump_core_and_abort(int target_sig)
{
CPUState *cpu = thread_cpu;
CPUArchState *env = cpu_env(cpu);
TaskState *ts = get_task_state(cpu);
int core_dumped = 0;
int host_sig;
struct sigaction act;
host_sig = target_to_host_signal(target_sig);
gdb_signalled(env, target_sig);
/* Dump core if supported by target binary format */
if (core_dump_signal(target_sig) && (ts->bprm->core_dump != NULL)) {
stop_all_tasks();
core_dumped =
((*ts->bprm->core_dump)(target_sig, env) == 0);
}
if (core_dumped) {
struct rlimit nodump;
/*
* We already dumped the core of target process, we don't want
* a coredump of qemu itself.
*/
getrlimit(RLIMIT_CORE, &nodump);
nodump.rlim_cur = 0;
setrlimit(RLIMIT_CORE, &nodump);
(void) fprintf(stderr, "qemu: uncaught target signal %d (%s) "
"- %s\n", target_sig, strsignal(host_sig), "core dumped");
}
/*
* The proper exit code for dying from an uncaught signal is
* -<signal>. The kernel doesn't allow exit() or _exit() to pass
* a negative value. To get the proper exit code we need to
* actually die from an uncaught signal. Here the default signal
* handler is installed, we send ourself a signal and we wait for
* it to arrive.
*/
memset(&act, 0, sizeof(act));
sigfillset(&act.sa_mask);
act.sa_handler = SIG_DFL;
sigaction(host_sig, &act, NULL);
kill(getpid(), host_sig);
/*
* Make sure the signal isn't masked (just reuse the mask inside
* of act).
*/
sigdelset(&act.sa_mask, host_sig);
sigsuspend(&act.sa_mask);
/* unreachable */
abort();
}
/*
* Queue a signal so that it will be send to the virtual CPU as soon as
* possible.
*/
void queue_signal(CPUArchState *env, int sig, int si_type,
target_siginfo_t *info)
{
CPUState *cpu = env_cpu(env);
TaskState *ts = get_task_state(cpu);
trace_user_queue_signal(env, sig);
info->si_code = deposit32(info->si_code, 24, 8, si_type);
ts->sync_signal.info = *info;
ts->sync_signal.pending = sig;
/* Signal that a new signal is pending. */
qatomic_set(&ts->signal_pending, 1);
return;
}
static int fatal_signal(int sig)
{
switch (sig) {
case TARGET_SIGCHLD:
case TARGET_SIGURG:
case TARGET_SIGWINCH:
case TARGET_SIGINFO:
/* Ignored by default. */
return 0;
case TARGET_SIGCONT:
case TARGET_SIGSTOP:
case TARGET_SIGTSTP:
case TARGET_SIGTTIN:
case TARGET_SIGTTOU:
/* Job control signals. */
return 0;
default:
return 1;
}
}
/*
* Force a synchronously taken QEMU_SI_FAULT signal. For QEMU the
* 'force' part is handled in process_pending_signals().
*/
void force_sig_fault(int sig, int code, abi_ulong addr)
{
CPUState *cpu = thread_cpu;
target_siginfo_t info = {};
info.si_signo = sig;
info.si_errno = 0;
info.si_code = code;
info.si_addr = addr;
queue_signal(cpu_env(cpu), sig, QEMU_SI_FAULT, &info);
}
static void host_signal_handler(int host_sig, siginfo_t *info, void *puc)
{
CPUState *cpu = thread_cpu;
TaskState *ts = get_task_state(cpu);
target_siginfo_t tinfo;
ucontext_t *uc = puc;
struct emulated_sigtable *k;
int guest_sig;
uintptr_t pc = 0;
bool sync_sig = false;
/*
* Non-spoofed SIGSEGV and SIGBUS are synchronous, and need special
* handling wrt signal blocking and unwinding.
*/
if ((host_sig == SIGSEGV || host_sig == SIGBUS) && info->si_code > 0) {
MMUAccessType access_type;
uintptr_t host_addr;
abi_ptr guest_addr;
bool is_write;
host_addr = (uintptr_t)info->si_addr;
/*
* Convert forcefully to guest address space: addresses outside
* reserved_va are still valid to report via SEGV_MAPERR.
*/
guest_addr = h2g_nocheck(host_addr);
pc = host_signal_pc(uc);
is_write = host_signal_write(info, uc);
access_type = adjust_signal_pc(&pc, is_write);
if (host_sig == SIGSEGV) {
bool maperr = true;
if (info->si_code == SEGV_ACCERR && h2g_valid(host_addr)) {
/* If this was a write to a TB protected page, restart. */
if (is_write &&
handle_sigsegv_accerr_write(cpu, &uc->uc_sigmask,
pc, guest_addr)) {
return;
}
/*
* With reserved_va, the whole address space is PROT_NONE,
* which means that we may get ACCERR when we want MAPERR.
*/
if (page_get_flags(guest_addr) & PAGE_VALID) {
maperr = false;
} else {
info->si_code = SEGV_MAPERR;
}
}
sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL);
cpu_loop_exit_sigsegv(cpu, guest_addr, access_type, maperr, pc);
} else {
sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL);
if (info->si_code == BUS_ADRALN) {
cpu_loop_exit_sigbus(cpu, guest_addr, access_type, pc);
}
}
sync_sig = true;
}
/* Get the target signal number. */
guest_sig = host_to_target_signal(host_sig);
if (guest_sig < 1 || guest_sig > TARGET_NSIG) {
return;
}
trace_user_host_signal(cpu, host_sig, guest_sig);
host_to_target_siginfo_noswap(&tinfo, info);
k = &ts->sigtab[guest_sig - 1];
k->info = tinfo;
k->pending = guest_sig;
ts->signal_pending = 1;
/*
* For synchronous signals, unwind the cpu state to the faulting
* insn and then exit back to the main loop so that the signal
* is delivered immediately.
*/
if (sync_sig) {
cpu->exception_index = EXCP_INTERRUPT;
cpu_loop_exit_restore(cpu, pc);
}
rewind_if_in_safe_syscall(puc);
/*
* Block host signals until target signal handler entered. We
* can't block SIGSEGV or SIGBUS while we're executing guest
* code in case the guest code provokes one in the window between
* now and it getting out to the main loop. Signals will be
* unblocked again in process_pending_signals().
*/
sigfillset(&uc->uc_sigmask);
sigdelset(&uc->uc_sigmask, SIGSEGV);
sigdelset(&uc->uc_sigmask, SIGBUS);
/* Interrupt the virtual CPU as soon as possible. */
cpu_exit(thread_cpu);
}
/* do_sigaltstack() returns target values and errnos. */
/* compare to kern/kern_sig.c sys_sigaltstack() and kern_sigaltstack() */
abi_long do_sigaltstack(abi_ulong uss_addr, abi_ulong uoss_addr, abi_ulong sp)
{
TaskState *ts = get_task_state(thread_cpu);
int ret;
target_stack_t oss;
if (uoss_addr) {
/* Save current signal stack params */
oss.ss_sp = tswapl(ts->sigaltstack_used.ss_sp);
oss.ss_size = tswapl(ts->sigaltstack_used.ss_size);
oss.ss_flags = tswapl(sas_ss_flags(ts, sp));
}
if (uss_addr) {
target_stack_t *uss;
target_stack_t ss;
size_t minstacksize = TARGET_MINSIGSTKSZ;
ret = -TARGET_EFAULT;
if (!lock_user_struct(VERIFY_READ, uss, uss_addr, 1)) {
goto out;
}
__get_user(ss.ss_sp, &uss->ss_sp);
__get_user(ss.ss_size, &uss->ss_size);
__get_user(ss.ss_flags, &uss->ss_flags);
unlock_user_struct(uss, uss_addr, 0);
ret = -TARGET_EPERM;
if (on_sig_stack(ts, sp)) {
goto out;
}
ret = -TARGET_EINVAL;
if (ss.ss_flags != TARGET_SS_DISABLE
&& ss.ss_flags != TARGET_SS_ONSTACK
&& ss.ss_flags != 0) {
goto out;
}
if (ss.ss_flags == TARGET_SS_DISABLE) {
ss.ss_size = 0;
ss.ss_sp = 0;
} else {
ret = -TARGET_ENOMEM;
if (ss.ss_size < minstacksize) {
goto out;
}
}
ts->sigaltstack_used.ss_sp = ss.ss_sp;
ts->sigaltstack_used.ss_size = ss.ss_size;
}
if (uoss_addr) {
ret = -TARGET_EFAULT;
if (copy_to_user(uoss_addr, &oss, sizeof(oss))) {
goto out;
}
}
ret = 0;
out:
return ret;
}
/* do_sigaction() return host values and errnos */
int do_sigaction(int sig, const struct target_sigaction *act,
struct target_sigaction *oact)
{
struct target_sigaction *k;
struct sigaction act1;
int host_sig;
int ret = 0;
if (sig < 1 || sig > TARGET_NSIG) {
return -TARGET_EINVAL;
}
if ((sig == TARGET_SIGKILL || sig == TARGET_SIGSTOP) &&
act != NULL && act->_sa_handler != TARGET_SIG_DFL) {
return -TARGET_EINVAL;
}
if (block_signals()) {
return -TARGET_ERESTART;
}
k = &sigact_table[sig - 1];
if (oact) {
oact->_sa_handler = tswapal(k->_sa_handler);
oact->sa_flags = tswap32(k->sa_flags);
oact->sa_mask = k->sa_mask;
}
if (act) {
k->_sa_handler = tswapal(act->_sa_handler);
k->sa_flags = tswap32(act->sa_flags);
k->sa_mask = act->sa_mask;
/* Update the host signal state. */
host_sig = target_to_host_signal(sig);
if (host_sig != SIGSEGV && host_sig != SIGBUS) {
memset(&act1, 0, sizeof(struct sigaction));
sigfillset(&act1.sa_mask);
act1.sa_flags = SA_SIGINFO;
if (k->sa_flags & TARGET_SA_RESTART) {
act1.sa_flags |= SA_RESTART;
}
/*
* Note: It is important to update the host kernel signal mask to
* avoid getting unexpected interrupted system calls.
*/
if (k->_sa_handler == TARGET_SIG_IGN) {
act1.sa_sigaction = (void *)SIG_IGN;
} else if (k->_sa_handler == TARGET_SIG_DFL) {
if (fatal_signal(sig)) {
act1.sa_sigaction = host_signal_handler;
} else {
act1.sa_sigaction = (void *)SIG_DFL;
}
} else {
act1.sa_sigaction = host_signal_handler;
}
ret = sigaction(host_sig, &act1, NULL);
}
}
return ret;
}
static inline abi_ulong get_sigframe(struct target_sigaction *ka,
CPUArchState *env, size_t frame_size)
{
TaskState *ts = get_task_state(thread_cpu);
abi_ulong sp;
/* Use default user stack */
sp = get_sp_from_cpustate(env);
if ((ka->sa_flags & TARGET_SA_ONSTACK) && sas_ss_flags(ts, sp) == 0) {
sp = ts->sigaltstack_used.ss_sp + ts->sigaltstack_used.ss_size;
}
/* TODO: make this a target_arch function / define */
#if defined(TARGET_ARM)
return (sp - frame_size) & ~7;
#elif defined(TARGET_AARCH64)
return (sp - frame_size) & ~15;
#else
return sp - frame_size;
#endif
}
/* compare to $M/$M/exec_machdep.c sendsig and sys/kern/kern_sig.c sigexit */
static void setup_frame(int sig, int code, struct target_sigaction *ka,
target_sigset_t *set, target_siginfo_t *tinfo, CPUArchState *env)
{
struct target_sigframe *frame;
abi_ulong frame_addr;
int i;
frame_addr = get_sigframe(ka, env, sizeof(*frame));
trace_user_setup_frame(env, frame_addr);
if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
unlock_user_struct(frame, frame_addr, 1);
dump_core_and_abort(TARGET_SIGILL);
return;
}
memset(frame, 0, sizeof(*frame));
setup_sigframe_arch(env, frame_addr, frame, 0);
for (i = 0; i < TARGET_NSIG_WORDS; i++) {
__put_user(set->__bits[i], &frame->sf_uc.uc_sigmask.__bits[i]);
}
if (tinfo) {
frame->sf_si.si_signo = tinfo->si_signo;
frame->sf_si.si_errno = tinfo->si_errno;
frame->sf_si.si_code = tinfo->si_code;
frame->sf_si.si_pid = tinfo->si_pid;
frame->sf_si.si_uid = tinfo->si_uid;
frame->sf_si.si_status = tinfo->si_status;
frame->sf_si.si_addr = tinfo->si_addr;
/* see host_to_target_siginfo_noswap() for more details */
frame->sf_si.si_value.sival_ptr = tinfo->si_value.sival_ptr;
/*
* At this point, whatever is in the _reason union is complete
* and in target order, so just copy the whole thing over, even
* if it's too large for this specific signal.
* host_to_target_siginfo_noswap() and tswap_siginfo() have ensured
* that's so.
*/
memcpy(&frame->sf_si._reason, &tinfo->_reason,
sizeof(tinfo->_reason));
}
set_sigtramp_args(env, sig, frame, frame_addr, ka);
unlock_user_struct(frame, frame_addr, 1);
}
static int reset_signal_mask(target_ucontext_t *ucontext)
{
int i;
sigset_t blocked;
target_sigset_t target_set;
TaskState *ts = get_task_state(thread_cpu);
for (i = 0; i < TARGET_NSIG_WORDS; i++) {
__get_user(target_set.__bits[i], &ucontext->uc_sigmask.__bits[i]);
}
target_to_host_sigset_internal(&blocked, &target_set);
ts->signal_mask = blocked;
return 0;
}
/* See sys/$M/$M/exec_machdep.c sigreturn() */
long do_sigreturn(CPUArchState *env, abi_ulong addr)
{
long ret;
abi_ulong target_ucontext;
target_ucontext_t *ucontext = NULL;
/* Get the target ucontext address from the stack frame */
ret = get_ucontext_sigreturn(env, addr, &target_ucontext);
if (is_error(ret)) {
return ret;
}
trace_user_do_sigreturn(env, addr);
if (!lock_user_struct(VERIFY_READ, ucontext, target_ucontext, 0)) {
goto badframe;
}
/* Set the register state back to before the signal. */
if (set_mcontext(env, &ucontext->uc_mcontext, 1)) {
goto badframe;
}
/* And reset the signal mask. */
if (reset_signal_mask(ucontext)) {
goto badframe;
}
unlock_user_struct(ucontext, target_ucontext, 0);
return -TARGET_EJUSTRETURN;
badframe:
if (ucontext != NULL) {
unlock_user_struct(ucontext, target_ucontext, 0);
}
return -TARGET_EFAULT;
}
void signal_init(void)
{
TaskState *ts = get_task_state(thread_cpu);
struct sigaction act;
struct sigaction oact;
int i;
int host_sig;
/* Set the signal mask from the host mask. */
sigprocmask(0, 0, &ts->signal_mask);
sigfillset(&act.sa_mask);
act.sa_sigaction = host_signal_handler;
act.sa_flags = SA_SIGINFO;
for (i = 1; i <= TARGET_NSIG; i++) {
host_sig = target_to_host_signal(i);
sigaction(host_sig, NULL, &oact);
if (oact.sa_sigaction == (void *)SIG_IGN) {
sigact_table[i - 1]._sa_handler = TARGET_SIG_IGN;
} else if (oact.sa_sigaction == (void *)SIG_DFL) {
sigact_table[i - 1]._sa_handler = TARGET_SIG_DFL;
}
/*
* If there's already a handler installed then something has
* gone horribly wrong, so don't even try to handle that case.
* Install some handlers for our own use. We need at least
* SIGSEGV and SIGBUS, to detect exceptions. We can not just
* trap all signals because it affects syscall interrupt
* behavior. But do trap all default-fatal signals.
*/
if (fatal_signal(i)) {
sigaction(host_sig, &act, NULL);
}
}
}
static void handle_pending_signal(CPUArchState *env, int sig,
struct emulated_sigtable *k)
{
CPUState *cpu = env_cpu(env);
TaskState *ts = get_task_state(cpu);
struct target_sigaction *sa;
int code;
sigset_t set;
abi_ulong handler;
target_siginfo_t tinfo;
target_sigset_t target_old_set;
trace_user_handle_signal(env, sig);
k->pending = 0;
sig = gdb_handlesig(cpu, sig, NULL, &k->info, sizeof(k->info));
if (!sig) {
sa = NULL;
handler = TARGET_SIG_IGN;
} else {
sa = &sigact_table[sig - 1];
handler = sa->_sa_handler;
}
if (do_strace) {
print_taken_signal(sig, &k->info);
}
if (handler == TARGET_SIG_DFL) {
/*
* default handler : ignore some signal. The other are job
* control or fatal.
*/
if (sig == TARGET_SIGTSTP || sig == TARGET_SIGTTIN ||
sig == TARGET_SIGTTOU) {
kill(getpid(), SIGSTOP);
} else if (sig != TARGET_SIGCHLD && sig != TARGET_SIGURG &&
sig != TARGET_SIGINFO && sig != TARGET_SIGWINCH &&
sig != TARGET_SIGCONT) {
dump_core_and_abort(sig);
}
} else if (handler == TARGET_SIG_IGN) {
/* ignore sig */
} else if (handler == TARGET_SIG_ERR) {
dump_core_and_abort(sig);
} else {
/* compute the blocked signals during the handler execution */
sigset_t *blocked_set;
target_to_host_sigset(&set, &sa->sa_mask);
/*
* SA_NODEFER indicates that the current signal should not be
* blocked during the handler.
*/
if (!(sa->sa_flags & TARGET_SA_NODEFER)) {
sigaddset(&set, target_to_host_signal(sig));
}
/*
* Save the previous blocked signal state to restore it at the
* end of the signal execution (see do_sigreturn).
*/
host_to_target_sigset_internal(&target_old_set, &ts->signal_mask);
blocked_set = ts->in_sigsuspend ?
&ts->sigsuspend_mask : &ts->signal_mask;
sigorset(&ts->signal_mask, blocked_set, &set);
ts->in_sigsuspend = false;
sigprocmask(SIG_SETMASK, &ts->signal_mask, NULL);
/* XXX VM86 on x86 ??? */
code = k->info.si_code; /* From host, so no si_type */
/* prepare the stack frame of the virtual CPU */
if (sa->sa_flags & TARGET_SA_SIGINFO) {
tswap_siginfo(&tinfo, &k->info);
setup_frame(sig, code, sa, &target_old_set, &tinfo, env);
} else {
setup_frame(sig, code, sa, &target_old_set, NULL, env);
}
if (sa->sa_flags & TARGET_SA_RESETHAND) {
sa->_sa_handler = TARGET_SIG_DFL;
}
}
}
void process_pending_signals(CPUArchState *env)
{
CPUState *cpu = env_cpu(env);
int sig;
sigset_t *blocked_set, set;
struct emulated_sigtable *k;
TaskState *ts = get_task_state(cpu);
while (qatomic_read(&ts->signal_pending)) {
sigfillset(&set);
sigprocmask(SIG_SETMASK, &set, 0);
restart_scan:
sig = ts->sync_signal.pending;
if (sig) {
/*
* Synchronous signals are forced by the emulated CPU in some way.
* If they are set to ignore, restore the default handler (see
* sys/kern_sig.c trapsignal() and execsigs() for this behavior)
* though maybe this is done only when forcing exit for non SIGCHLD.
*/
if (sigismember(&ts->signal_mask, target_to_host_signal(sig)) ||
sigact_table[sig - 1]._sa_handler == TARGET_SIG_IGN) {
sigdelset(&ts->signal_mask, target_to_host_signal(sig));
sigact_table[sig - 1]._sa_handler = TARGET_SIG_DFL;
}
handle_pending_signal(env, sig, &ts->sync_signal);
}
k = ts->sigtab;
for (sig = 1; sig <= TARGET_NSIG; sig++, k++) {
blocked_set = ts->in_sigsuspend ?
&ts->sigsuspend_mask : &ts->signal_mask;
if (k->pending &&
!sigismember(blocked_set, target_to_host_signal(sig))) {
handle_pending_signal(env, sig, k);
/*
* Restart scan from the beginning, as handle_pending_signal
* might have resulted in a new synchronous signal (eg SIGSEGV).
*/
goto restart_scan;
}
}
/*
* Unblock signals and check one more time. Unblocking signals may cause
* us to take another host signal, which will set signal_pending again.
*/
qatomic_set(&ts->signal_pending, 0);
ts->in_sigsuspend = false;
set = ts->signal_mask;
sigdelset(&set, SIGSEGV);
sigdelset(&set, SIGBUS);
sigprocmask(SIG_SETMASK, &set, 0);
}
ts->in_sigsuspend = false;
}
void cpu_loop_exit_sigsegv(CPUState *cpu, target_ulong addr,
MMUAccessType access_type, bool maperr, uintptr_t ra)
{
const TCGCPUOps *tcg_ops = CPU_GET_CLASS(cpu)->tcg_ops;
if (tcg_ops->record_sigsegv) {
tcg_ops->record_sigsegv(cpu, addr, access_type, maperr, ra);
}
force_sig_fault(TARGET_SIGSEGV,
maperr ? TARGET_SEGV_MAPERR : TARGET_SEGV_ACCERR,
addr);
cpu->exception_index = EXCP_INTERRUPT;
cpu_loop_exit_restore(cpu, ra);
}
void cpu_loop_exit_sigbus(CPUState *cpu, target_ulong addr,
MMUAccessType access_type, uintptr_t ra)
{
const TCGCPUOps *tcg_ops = CPU_GET_CLASS(cpu)->tcg_ops;
if (tcg_ops->record_sigbus) {
tcg_ops->record_sigbus(cpu, addr, access_type, ra);
}
force_sig_fault(TARGET_SIGBUS, TARGET_BUS_ADRALN, addr);
cpu->exception_index = EXCP_INTERRUPT;
cpu_loop_exit_restore(cpu, ra);
}