LONG NTAPI vectored_exception_handler_internal(LPEXCEPTION_POINTERS nt_exception)
{
DWORD code = nt_exception->ExceptionRecord->ExceptionCode;
void* fault_addr = nt_exception->ExceptionRecord->ExceptionAddress;
Registers regs;
// Convert NT context to Registers
port_thread_context_to_regs(®s, nt_exception->ContextRecord);
// Check if TLS structure is set - probably we should produce minidump
port_tls_data_t* tlsdata = get_private_tls_data();
if (!tlsdata) // Tread is not attached - attach thread temporarily
{
int res;
tlsdata = (port_tls_data_t*)STD_MALLOC(sizeof(port_tls_data_t));
if (tlsdata) // Try to attach the thread
res = port_thread_attach_local(tlsdata, TRUE, TRUE, 0);
if (!tlsdata || res != 0)
{ // Can't process correctly; perform default actions
if (FLAG_CORE)
create_minidump(nt_exception);
if (FLAG_DBG)
{
show_debugger_dialog(); // Workaround; EXCEPTION_CONTINUE_SEARCH does not work
_exit(-1);
return EXCEPTION_CONTINUE_SEARCH; // Assert dialog
}
_exit(-1);
}
// SO for alien thread can't be processed out of VEH
if (code == STATUS_STACK_OVERFLOW &&
sd_is_handler_registered(PORT_SIGNAL_STACK_OVERFLOW))
{
int result;
size_t alt_stack_size = ALT_PAGES_COUNT*tlsdata->guard_page_size;
void* alt_stack = map_alt_stack(alt_stack_size);
void* stack_bottom = (void*)((POINTER_SIZE_INT)alt_stack + alt_stack_size);
if (alt_stack)
result = (int)(POINTER_SIZE_INT)port_call_alt_stack(
port_process_signal, stack_bottom, 4,
PORT_SIGNAL_STACK_OVERFLOW, ®s, fault_addr, FALSE);
else
result = port_process_signal(PORT_SIGNAL_STACK_OVERFLOW, ®s, fault_addr, FALSE);
if (result == 0)
{
if (port_thread_detach_temporary() == 0)
STD_FREE(tlsdata);
if (alt_stack)
unmap_alt_stack(alt_stack, alt_stack_size);
return EXCEPTION_CONTINUE_EXECUTION;
}
if (FLAG_CORE)
{
if (alt_stack)
port_call_alt_stack(create_minidump, stack_bottom, 1, nt_exception);
else
create_minidump(nt_exception);
}
if (alt_stack)
unmap_alt_stack(alt_stack, alt_stack_size);
if (result > 0)
{
show_debugger_dialog(); // Workaround; EXCEPTION_CONTINUE_SEARCH does not work
_exit(-1);
shutdown_signals();
return EXCEPTION_CONTINUE_SEARCH; // Assert dialog
}
_exit(-1);
}
}
if (tlsdata->produce_core)
{
create_minidump(nt_exception);
if (!tlsdata->debugger)
_exit(-1);
}
if (tlsdata->debugger)
{
show_debugger_dialog(); // Workaround
_exit(-1);
// Go to handler to restore CRT/VEH settings and crash once again
// port_set_longjump_regs(&prepare_assert_dialog, ®s, 1, ®s);
// port_thread_regs_to_context(nt_exception->ContextRecord, ®s);
// return EXCEPTION_CONTINUE_EXECUTION;
}
switch (code)
{
case STATUS_STACK_OVERFLOW:
if (!sd_is_handler_registered(PORT_SIGNAL_STACK_OVERFLOW))
return EXCEPTION_CONTINUE_SEARCH;
break;
case STATUS_ACCESS_VIOLATION:
if (!sd_is_handler_registered(PORT_SIGNAL_GPF))
return EXCEPTION_CONTINUE_SEARCH;
break;
case JVMTI_EXCEPTION_STATUS:
if (!sd_is_handler_registered(PORT_SIGNAL_BREAKPOINT))
return EXCEPTION_CONTINUE_SEARCH;
break;
case STATUS_INTEGER_DIVIDE_BY_ZERO:
case EXCEPTION_FLT_DIVIDE_BY_ZERO:
case EXCEPTION_FLT_OVERFLOW:
case EXCEPTION_FLT_UNDERFLOW:
case EXCEPTION_INT_OVERFLOW:
if (!sd_is_handler_registered(PORT_SIGNAL_ARITHMETIC))
return EXCEPTION_CONTINUE_SEARCH;
break;
default:
return EXCEPTION_CONTINUE_SEARCH;
}
if (code == STATUS_STACK_OVERFLOW)
{
tlsdata->guard_page_set = FALSE; // GUARD_PAGE was cleared by OS
if (!tlsdata->restore_guard_page)
tlsdata->restore_guard_page = TRUE;
}
// Prepare to transfering control out of VEH handler
port_set_longjump_regs(&c_handler, ®s, 4, ®s,
nt_exception->ExceptionRecord->ExceptionAddress,
(void*)(size_t)nt_exception->ExceptionRecord->ExceptionCode,
(void*)(size_t)nt_exception->ExceptionRecord->ExceptionFlags);
// Convert prepared Registers back to NT context
port_thread_regs_to_context(nt_exception->ContextRecord, ®s);
// Return from VEH - presumably continue execution
return EXCEPTION_CONTINUE_EXECUTION;
}
static void general_signal_handler(int signum, siginfo_t* info, void* context)
{
Registers regs;
if (!context)
return;
// Convert OS context to Registers
port_thread_context_to_regs(®s, (ucontext_t*)context);
void* fault_addr = info ? info->si_addr : NULL;
// Check if SIGSEGV is produced by port_read/write_memory
port_tls_data_t* tlsdata = get_private_tls_data();
if (tlsdata && tlsdata->violation_flag)
{
tlsdata->violation_flag = 0;
regs.set_ip(tlsdata->restart_address);
return;
}
if (!tlsdata) // Tread is not attached - attach thread temporarily
{
int res;
tlsdata = (port_tls_data_t*)STD_MALLOC(sizeof(port_tls_data_t));
if (tlsdata) // Try to attach the thread
res = port_thread_attach_local(tlsdata, TRUE, TRUE, 0);
if (!tlsdata || res != 0)
{ // Can't process correctly; perform default actions
if (FLAG_DBG)
{
bool result = gdb_crash_handler(®s);
_exit(-1); // Exit process if not sucessful...
}
if (FLAG_CORE &&
signum != SIGABRT) // SIGABRT can't be rethrown
{
signal(signum, SIG_DFL); // setup default handler
return;
}
_exit(-1);
}
// SIGSEGV can represent SO which can't be processed out of signal handler
if (signum == SIGSEGV && // This can occur only when a user set an alternative stack
is_stack_overflow(tlsdata, fault_addr))
{
int result = port_process_signal(PORT_SIGNAL_STACK_OVERFLOW, ®s, fault_addr, FALSE);
if (result == 0)
{
if (port_thread_detach_temporary() == 0)
STD_FREE(tlsdata);
return;
}
if (result > 0)
tlsdata->debugger = TRUE;
else
{
if (FLAG_CORE)
{ // Rethrow crash to generate core
signal(signum, SIG_DFL); // setup default handler
return;
}
_exit(-1);
}
}
}
if (tlsdata->debugger)
{
bool result = gdb_crash_handler(®s);
_exit(-1); // Exit process if not sucessful...
}
if (signum == SIGABRT && // SIGABRT can't be trown again from c_handler
FLAG_DBG)
{ // So attaching GDB right here
bool result = gdb_crash_handler(®s);
_exit(-1); // Exit process if not sucessful...
}
if (signum == SIGSEGV &&
is_stack_overflow(tlsdata, fault_addr))
{
// Second SO while previous SO is not processed yet - is GPF
if (tlsdata->restore_guard_page)
tlsdata->restore_guard_page = FALSE;
else
{ // To process signal on protected stack area
port_thread_clear_guard_page();
// Note: the call above does not disable alternative stack
// It can't be made while we are on alternative stack
// Alt stack will be disabled explicitly in c_handler()
tlsdata->restore_guard_page = TRUE;
}
}
// Prepare registers for transfering control out of signal handler
void* callback = (void*)&c_handler;
port_set_longjump_regs(callback, ®s, 3,
®s, (void*)(size_t)signum, fault_addr);
// Convert prepared Registers back to OS context
port_thread_regs_to_context((ucontext_t*)context, ®s);
// Return from signal handler to go to C handler
}
