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