inline static bool checkPrefetch(sigcontext* uc, address pc) {
if (pc == (address) Fetch32PFI) {
set_cont_address(uc, address(Fetch32Resume));
return true;
}
if (pc == (address) FetchNPFI) {
set_cont_address(uc, address(FetchNResume));
return true;
}
return false;
}
inline static bool checkPrefetch(sigcontext* uc, address pc) {
if (StubRoutines::is_safefetch_fault(pc)) {
set_cont_address(uc, address(StubRoutines::continuation_for_safefetch_fault(pc)));
return true;
}
return false;
}
extern "C" JNIEXPORT int
JVM_handle_linux_signal(int sig,
siginfo_t* info,
void* ucVoid,
int abort_if_unrecognized) {
// in fact this isn't ucontext_t* at all, but struct sigcontext*
// but Linux porting layer uses ucontext_t, so to minimize code change
// we cast as needed
ucontext_t* ucFake = (ucontext_t*) ucVoid;
sigcontext* uc = (sigcontext*)ucVoid;
Thread* t = ThreadLocalStorage::get_thread_slow();
SignalHandlerMark shm(t);
// Note: it's not uncommon that JNI code uses signal/sigset to install
// then restore certain signal handler (e.g. to temporarily block SIGPIPE,
// or have a SIGILL handler when detecting CPU type). When that happens,
// JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
// avoid unnecessary crash when libjsig is not preloaded, try handle signals
// that do not require siginfo/ucontext first.
if (sig == SIGPIPE || sig == SIGXFSZ) {
// allow chained handler to go first
if (os::Linux::chained_handler(sig, info, ucVoid)) {
return true;
} else {
if (PrintMiscellaneous && (WizardMode || Verbose)) {
char buf[64];
warning("Ignoring %s - see bugs 4229104 or 646499219",
os::exception_name(sig, buf, sizeof(buf)));
}
return true;
}
}
JavaThread* thread = NULL;
VMThread* vmthread = NULL;
if (os::Linux::signal_handlers_are_installed) {
if (t != NULL ){
if(t->is_Java_thread()) {
thread = (JavaThread*)t;
}
else if(t->is_VM_thread()){
vmthread = (VMThread *)t;
}
}
}
// decide if this trap can be handled by a stub
address stub = NULL;
address pc = NULL;
address npc = NULL;
//%note os_trap_1
if (info != NULL && uc != NULL && thread != NULL) {
pc = address(SIG_PC(uc));
npc = address(SIG_NPC(uc));
// Check to see if we caught the safepoint code in the
// process of write protecting the memory serialization page.
// It write enables the page immediately after protecting it
// so we can just return to retry the write.
if ((sig == SIGSEGV) && checkSerializePage(thread, (address)info->si_addr)) {
// Block current thread until the memory serialize page permission restored.
os::block_on_serialize_page_trap();
return 1;
}
if (checkPrefetch(uc, pc)) {
return 1;
}
// Handle ALL stack overflow variations here
if (sig == SIGSEGV) {
if (checkOverflow(uc, pc, (address)info->si_addr, thread, &stub)) {
return 1;
}
}
if (sig == SIGBUS &&
thread->thread_state() == _thread_in_vm &&
thread->doing_unsafe_access()) {
stub = StubRoutines::handler_for_unsafe_access();
}
if (thread->thread_state() == _thread_in_Java) {
do {
// Java thread running in Java code => find exception handler if any
// a fault inside compiled code, the interpreter, or a stub
if ((sig == SIGSEGV) && checkPollingPage(pc, (address)info->si_addr, &stub)) {
break;
}
if ((sig == SIGBUS) && checkByteBuffer(pc, &stub)) {
break;
}
if ((sig == SIGSEGV || sig == SIGBUS) &&
checkVerifyOops(pc, (address)info->si_addr, &stub)) {
break;
}
if ((sig == SIGSEGV) && checkZombie(uc, &pc, &stub)) {
break;
}
if ((sig == SIGILL) && checkICMiss(uc, &pc, &stub)) {
break;
}
if ((sig == SIGFPE) && checkFPFault(pc, info->si_code, thread, &stub)) {
break;
}
if ((sig == SIGSEGV) &&
checkNullPointer(pc, (intptr_t)info->si_addr, thread, &stub)) {
break;
}
} while (0);
// jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
// and the heap gets shrunk before the field access.
if ((sig == SIGSEGV) || (sig == SIGBUS)) {
checkFastJNIAccess(pc, &stub);
}
}
if (stub != NULL) {
// save all thread context in case we need to restore it
thread->set_saved_exception_pc(pc);
thread->set_saved_exception_npc(npc);
set_cont_address(uc, stub);
return true;
}
}
// signal-chaining
if (os::Linux::chained_handler(sig, info, ucVoid)) {
return true;
}
if (!abort_if_unrecognized) {
// caller wants another chance, so give it to him
return false;
}
if (pc == NULL && uc != NULL) {
pc = os::Linux::ucontext_get_pc((ucontext_t*)uc);
}
// unmask current signal
sigset_t newset;
sigemptyset(&newset);
sigaddset(&newset, sig);
sigprocmask(SIG_UNBLOCK, &newset, NULL);
VMError err(t, sig, pc, info, ucVoid);
err.report_and_die();
ShouldNotReachHere();
}
