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tag: 20121227
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/*
* Emulation of Linux signals
*
* Copyright (c) 2003 Fabrice Bellard
*
* 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 <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <unistd.h>
#include <signal.h>
#include <errno.h>
#include <sys/ucontext.h>
#ifdef __ia64__
#undef uc_mcontext
#undef uc_sigmask
#undef uc_stack
#undef uc_link
#endif
#include <signal.h>
#include "qemu.h"
#include "qemu-common.h"
#define DEBUG_SIGNAL
#define MAX_SIGQUEUE_SIZE 1024
struct sigqueue {
struct sigqueue *next;
target_siginfo_t info;
};
struct emulated_sigaction {
struct target_sigaction sa;
int pending; /* true if signal is pending */
struct sigqueue *first;
struct sigqueue info; /* in order to always have memory for the
first signal, we put it here */
};
static struct sigaltstack target_sigaltstack_used = {
0, 0, SA_DISABLE
};
static struct emulated_sigaction sigact_table[NSIG];
static struct sigqueue sigqueue_table[MAX_SIGQUEUE_SIZE]; /* siginfo queue */
static struct sigqueue *first_free; /* first free siginfo queue entry */
static int signal_pending; /* non zero if a signal may be pending */
static void host_signal_handler(int host_signum, siginfo_t *info,
void *puc);
static inline int host_to_target_signal(int sig)
{
return sig;
}
static inline int target_to_host_signal(int sig)
{
return sig;
}
/* siginfo conversion */
void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info)
{
}
void target_to_host_siginfo(siginfo_t *info, const target_siginfo_t *tinfo)
{
}
void signal_init(void)
{
struct sigaction act;
int i;
/* set all host signal handlers. ALL signals are blocked during
the handlers to serialize them. */
sigfillset(&act.sa_mask);
act.sa_flags = SA_SIGINFO;
act.sa_sigaction = host_signal_handler;
for(i = 1; i < NSIG; i++) {
sigaction(i, &act, NULL);
}
memset(sigact_table, 0, sizeof(sigact_table));
first_free = &sigqueue_table[0];
for(i = 0; i < MAX_SIGQUEUE_SIZE - 1; i++)
sigqueue_table[i].next = &sigqueue_table[i + 1];
sigqueue_table[MAX_SIGQUEUE_SIZE - 1].next = NULL;
}
/* signal queue handling */
static inline struct sigqueue *alloc_sigqueue(void)
{
struct sigqueue *q = first_free;
if (!q)
return NULL;
first_free = q->next;
return q;
}
static inline void free_sigqueue(struct sigqueue *q)
{
q->next = first_free;
first_free = q;
}
/* abort execution with signal */
void QEMU_NORETURN force_sig(int sig)
{
int host_sig;
host_sig = target_to_host_signal(sig);
fprintf(stderr, "qemu: uncaught target signal %d (%s) - exiting\n",
sig, strsignal(host_sig));
_exit(-host_sig);
}
/* queue a signal so that it will be send to the virtual CPU as soon
as possible */
int queue_signal(int sig, target_siginfo_t *info)
{
struct emulated_sigaction *k;
struct sigqueue *q, **pq;
target_ulong handler;
#if defined(DEBUG_SIGNAL)
fprintf(stderr, "queue_signal: sig=%d\n",
sig);
#endif
k = &sigact_table[sig - 1];
handler = (target_ulong)k->sa.sa_handler;
if (handler == SIG_DFL) {
/* default handler : ignore some signal. The other are fatal */
if (sig != SIGCHLD &&
sig != SIGURG &&
sig != SIGWINCH) {
force_sig(sig);
} else {
return 0; /* indicate ignored */
}
} else if (handler == host_to_target_signal(SIG_IGN)) {
/* ignore signal */
return 0;
} else if (handler == host_to_target_signal(SIG_ERR)) {
force_sig(sig);
} else {
pq = &k->first;
if (!k->pending) {
/* first signal */
q = &k->info;
} else {
q = alloc_sigqueue();
if (!q)
return -EAGAIN;
while (*pq != NULL)
pq = &(*pq)->next;
}
*pq = q;
q->info = *info;
q->next = NULL;
k->pending = 1;
/* signal that a new signal is pending */
signal_pending = 1;
return 1; /* indicates that the signal was queued */
}
}
static void host_signal_handler(int host_signum, siginfo_t *info,
void *puc)
{
int sig;
target_siginfo_t tinfo;
/* the CPU emulator uses some host signals to detect exceptions,
we we forward to it some signals */
if (host_signum == SIGSEGV || host_signum == SIGBUS) {
if (cpu_signal_handler(host_signum, (void*)info, puc))
return;
}
/* get target signal number */
sig = host_to_target_signal(host_signum);
if (sig < 1 || sig > NSIG)
return;
#if defined(DEBUG_SIGNAL)
fprintf(stderr, "qemu: got signal %d\n", sig);
#endif
if (queue_signal(sig, &tinfo) == 1) {
/* interrupt the virtual CPU as soon as possible */
cpu_exit(global_env);
}
}
int do_sigaltstack(const struct sigaltstack *ss, struct sigaltstack *oss)
{
/* XXX: test errors */
if(oss)
{
oss->ss_sp = tswap32(target_sigaltstack_used.ss_sp);
oss->ss_size = tswap32(target_sigaltstack_used.ss_size);
oss->ss_flags = tswap32(target_sigaltstack_used.ss_flags);
}
if(ss)
{
target_sigaltstack_used.ss_sp = tswap32(ss->ss_sp);
target_sigaltstack_used.ss_size = tswap32(ss->ss_size);
target_sigaltstack_used.ss_flags = tswap32(ss->ss_flags);
}
return 0;
}
int do_sigaction(int sig, const struct sigaction *act,
struct sigaction *oact)
{
struct emulated_sigaction *k;
struct sigaction act1;
int host_sig;
if (sig < 1 || sig > NSIG)
return -EINVAL;
k = &sigact_table[sig - 1];
#if defined(DEBUG_SIGNAL)
fprintf(stderr, "sigaction 1 sig=%d act=0x%08x, oact=0x%08x\n",
sig, (int)act, (int)oact);
#endif
if (oact) {
#if defined(DEBUG_SIGNAL)
fprintf(stderr, "sigaction 1 sig=%d act=0x%08x, oact=0x%08x\n",
sig, (int)act, (int)oact);
#endif
oact->sa_handler = tswapl(k->sa.sa_handler);
oact->sa_flags = tswapl(k->sa.sa_flags);
oact->sa_mask = tswapl(k->sa.sa_mask);
}
if (act) {
#if defined(DEBUG_SIGNAL)
fprintf(stderr, "sigaction handler 0x%x flag 0x%x mask 0x%x\n",
act->sa_handler, act->sa_flags, act->sa_mask);
#endif
k->sa.sa_handler = tswapl(act->sa_handler);
k->sa.sa_flags = tswapl(act->sa_flags);
k->sa.sa_mask = tswapl(act->sa_mask);
/* we update the host signal state */
host_sig = target_to_host_signal(sig);
if (host_sig != SIGSEGV && host_sig != SIGBUS) {
#if defined(DEBUG_SIGNAL)
fprintf(stderr, "sigaction handler going to call sigaction\n",
act->sa_handler, act->sa_flags, act->sa_mask);
#endif
sigfillset(&act1.sa_mask);
act1.sa_flags = SA_SIGINFO;
if (k->sa.sa_flags & 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.sa_handler == SIG_IGN) {
act1.sa_sigaction = (void *)SIG_IGN;
} else if (k->sa.sa_handler == SIG_DFL) {
act1.sa_sigaction = (void *)SIG_DFL;
} else {
act1.sa_sigaction = host_signal_handler;
}
sigaction(host_sig, &act1, NULL);
}
}
return 0;
}
#ifdef TARGET_I386
static inline void *
get_sigframe(struct emulated_sigaction *ka, CPUX86State *env, size_t frame_size)
{
/* XXX Fix that */
if(target_sigaltstack_used.ss_flags & SA_DISABLE)
{
int esp;
/* Default to using normal stack */
esp = env->regs[R_ESP];
return (void *)((esp - frame_size) & -8ul);
}
else
{
return target_sigaltstack_used.ss_sp;
}
}
static void setup_frame(int sig, struct emulated_sigaction *ka,
void *set, CPUState *env)
{
void *frame;
int i, err = 0;
fprintf(stderr, "setup_frame %d\n", sig);
frame = get_sigframe(ka, env, sizeof(*frame));
/* Set up registers for signal handler */
env->regs[R_ESP] = (unsigned long) frame;
env->eip = (unsigned long) ka->sa.sa_handler;
env->eflags &= ~TF_MASK;
return;
give_sigsegv:
if (sig == SIGSEGV)
ka->sa.sa_handler = SIG_DFL;
force_sig(SIGSEGV /* , current */);
}
long do_sigreturn(CPUState *env, int num)
{
int i = 0;
struct target_sigcontext *scp = get_int_arg(&i, env);
/* XXX Get current signal number */
/* XXX Adjust accordin to sc_onstack, sc_mask */
if(tswapl(scp->sc_onstack) & 0x1)
target_sigaltstack_used.ss_flags |= ~SA_DISABLE;
else
target_sigaltstack_used.ss_flags &= SA_DISABLE;
int set = tswapl(scp->sc_eax);
sigprocmask(SIG_SETMASK, &set, NULL);
fprintf(stderr, "do_sigreturn: partially implemented %x EAX:%x EBX:%x\n", scp->sc_mask, tswapl(scp->sc_eax), tswapl(scp->sc_ebx));
fprintf(stderr, "ECX:%x EDX:%x EDI:%x\n", scp->sc_ecx, tswapl(scp->sc_edx), tswapl(scp->sc_edi));
fprintf(stderr, "EIP:%x\n", tswapl(scp->sc_eip));
env->regs[R_EAX] = tswapl(scp->sc_eax);
env->regs[R_EBX] = tswapl(scp->sc_ebx);
env->regs[R_ECX] = tswapl(scp->sc_ecx);
env->regs[R_EDX] = tswapl(scp->sc_edx);
env->regs[R_EDI] = tswapl(scp->sc_edi);
env->regs[R_ESI] = tswapl(scp->sc_esi);
env->regs[R_EBP] = tswapl(scp->sc_ebp);
env->regs[R_ESP] = tswapl(scp->sc_esp);
env->segs[R_SS].selector = (void*)tswapl(scp->sc_ss);
env->eflags = tswapl(scp->sc_eflags);
env->eip = tswapl(scp->sc_eip);
env->segs[R_CS].selector = (void*)tswapl(scp->sc_cs);
env->segs[R_DS].selector = (void*)tswapl(scp->sc_ds);
env->segs[R_ES].selector = (void*)tswapl(scp->sc_es);
env->segs[R_FS].selector = (void*)tswapl(scp->sc_fs);
env->segs[R_GS].selector = (void*)tswapl(scp->sc_gs);
/* Again, because our caller's caller will reset EAX */
return env->regs[R_EAX];
}
#else
static void setup_frame(int sig, struct emulated_sigaction *ka,
void *set, CPUState *env)
{
fprintf(stderr, "setup_frame: not implemented\n");
}
long do_sigreturn(CPUState *env, int num)
{
int i = 0;
struct target_sigcontext *scp = get_int_arg(&i, env);
fprintf(stderr, "do_sigreturn: not implemented\n");
return -ENOSYS;
}
#endif
void process_pending_signals(void *cpu_env)
{
struct emulated_sigaction *k;
struct sigqueue *q;
target_ulong handler;
int sig;
if (!signal_pending)
return;
k = sigact_table;
for(sig = 1; sig <= NSIG; sig++) {
if (k->pending)
goto handle_signal;
k++;
}
/* if no signal is pending, just return */
signal_pending = 0;
return;
handle_signal:
#ifdef DEBUG_SIGNAL
fprintf(stderr, "qemu: process signal %d\n", sig);
#endif
/* dequeue signal */
q = k->first;
k->first = q->next;
if (!k->first)
k->pending = 0;
sig = gdb_handlesig (cpu_env, sig);
if (!sig) {
fprintf (stderr, "Lost signal\n");
abort();
}
handler = k->sa.sa_handler;
if (handler == SIG_DFL) {
/* default handler : ignore some signal. The other are fatal */
if (sig != SIGCHLD &&
sig != SIGURG &&
sig != SIGWINCH) {
force_sig(sig);
}
} else if (handler == SIG_IGN) {
/* ignore sig */
} else if (handler == SIG_ERR) {
force_sig(sig);
} else {
setup_frame(sig, k, 0, cpu_env);
if (k->sa.sa_flags & SA_RESETHAND)
k->sa.sa_handler = SIG_DFL;
}
if (q != &k->info)
free_sigqueue(q);
}
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