* 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
* 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 "qemu/osdep.h"
+#include "qemu/log.h"
#include "qemu.h"
-#include "target_signal.h"
+#include "gdbstub/user.h"
+#include "signal-common.h"
+#include "trace.h"
+#include "hw/core/tcg-cpu-ops.h"
+#include "host-signal.h"
-//#define DEBUG_SIGNAL
+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 = (TaskState *)thread_cpu->opaque;
+ 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)
+{
+ CPUArchState *env = thread_cpu->env_ptr;
+ CPUState *cpu = env_cpu(env);
+ TaskState *ts = cpu->opaque;
+ 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 = cpu->opaque;
+
+ 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;
+ CPUArchState *env = cpu->env_ptr;
+ target_siginfo_t info = {};
+
+ info.si_signo = sig;
+ info.si_errno = 0;
+ info.si_code = code;
+ info.si_addr = addr;
+ queue_signal(env, sig, QEMU_SI_FAULT, &info);
+}
+
+static void host_signal_handler(int host_sig, siginfo_t *info, void *puc)
+{
+ CPUArchState *env = thread_cpu->env_ptr;
+ CPUState *cpu = env_cpu(env);
+ TaskState *ts = cpu->opaque;
+ 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 = (TaskState *)thread_cpu->opaque;
+ 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 = (TaskState *)thread_cpu->opaque;
+ 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 = (TaskState *)thread_cpu->opaque;
+
+ 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 = (TaskState *)thread_cpu->opaque;
+ 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++) {
+#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);
+ }
+ }
}
-void process_pending_signals(CPUArchState *cpu_env)
+static void handle_pending_signal(CPUArchState *env, int sig,
+ struct emulated_sigtable *k)
{
+ CPUState *cpu = env_cpu(env);
+ TaskState *ts = cpu->opaque;
+ 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);
+ 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 = cpu->opaque;
+
+ 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 struct 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 struct 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);
}
projects / mirror_qemu.git / blobdiff