/* helper for find_vm_areas_via_probe() and get_memory_info_from_os()
* returns the passed-in pc if the probe was successful; else, returns
* where the next probe should be (to skip DR memory).
* if the probe was successful, returns in prot the results.
*/
static app_pc
probe_address(dcontext_t *dcontext, app_pc pc_in, byte *our_heap_start,
byte *our_heap_end, OUT uint *prot)
{
app_pc base;
size_t size;
app_pc pc = (app_pc)ALIGN_BACKWARD(pc_in, PAGE_SIZE);
ASSERT(ALIGNED(pc, PAGE_SIZE));
ASSERT(prot != NULL);
*prot = MEMPROT_NONE;
/* skip our own vmheap */
if (pc >= our_heap_start && pc < our_heap_end)
return our_heap_end;
/* if no vmheap and we probe our own stack, the SIGSEGV handler will
* report stack overflow as it checks that prior to handling TRY
*/
if (is_stack_overflow(dcontext, pc))
return pc + PAGE_SIZE;
#ifdef VMX86_SERVER
/* Workaround for PR 380621 */
if (is_vmkernel_addr_in_user_space(pc, &base)) {
LOG(GLOBAL, LOG_VMAREAS, 4, "%s: skipping vmkernel region " PFX "-" PFX "\n",
__func__, pc, base);
return base;
}
#endif
/* Only for find_vm_areas_via_probe(), skip modules added by
* dl_iterate_get_areas_cb. Subsequent probes are about gettting
* info from OS, so do the actual probe. See PR 410907.
*/
if (!dynamo_initialized && get_memory_info(pc, &base, &size, prot))
return base + size;
TRY_EXCEPT(dcontext, /* try */
{
PROBE_READ_PC(pc);
*prot |= MEMPROT_READ;
},
/* except */
{
/* nothing: just continue */
});
/**
* @param classRecord Record for method class.
* @param methodRecord Calle's method record.
* @param retAddr What the PC should be upon return.
* @return true iff the stack frame was pushed.
*/
boolean dispatch_special (MethodRecord *methodRecord, byte *retAddr)
{
#if DEBUG_METHODS
int debug_ctr;
#endif
StackFrame *stackFrame;
byte newStackFrameIndex;
#if DEBUG_BYTECODE
printf ("\n------ dispatch special - %d ------------------\n\n",
methodRecord->signatureId);
#endif
#if DEBUG_METHODS
printf ("dispatch_special: %d, %d\n",
(int) methodRecord, (int) retAddr);
printf ("-- signature id = %d\n", methodRecord->signatureId);
printf ("-- code offset = %d\n", methodRecord->codeOffset);
printf ("-- flags = %d\n", methodRecord->mflags);
printf ("-- num params = %d\n", methodRecord->numParameters);
printf ("-- stack ptr = %d\n", (int) get_stack_ptr());
printf ("-- max stack ptr= %d\n", (int) (currentThread->stackArray + (get_array_size(currentThread->stackArray))*2));
#endif
pop_words (methodRecord->numParameters);
pc = retAddr;
if (is_native (methodRecord))
{
#if DEBUG_METHODS
printf ("-- native\n");
#endif
dispatch_native (methodRecord->signatureId, get_stack_ptr() + 1);
// Stack frame not pushed
return false;
}
newStackFrameIndex = currentThread->stackFrameArraySize;
if (newStackFrameIndex >= get_array_length((Object *) word2ptr (currentThread->stackFrameArray)))
{
#if !FIXED_STACK_SIZE
// int len = get_array_length((Object *) word2ptr (currentThread->stackFrameArray));
int newlen = get_array_length((Object *) word2ptr (currentThread->stackFrameArray)) * 3 / 2;
JINT newStackFrameArray = JNULL;
// Stack frames are indexed by a byte value so limit the size.
if (newlen <= 255)
{
// increase the stack frame size
newStackFrameArray = ptr2word(reallocate_array(word2ptr(currentThread->stackFrameArray), newlen));
}
// If can't allocate new stack, give in!
if (newStackFrameArray == JNULL)
{
#endif
throw_exception (stackOverflowError);
return false;
#if !FIXED_STACK_SIZE
}
// Assign new array
currentThread->stackFrameArray = newStackFrameArray;
#endif
}
if (newStackFrameIndex == 0)
{
// Assign NEW stack frame
stackFrame = stackframe_array();
}
else
{
#if DEBUG_METHODS
for (debug_ctr = 0; debug_ctr < methodRecord->numParameters; debug_ctr++)
printf ("-- param[%d] = %ld\n", debug_ctr, (long) get_stack_ptr()[debug_ctr+1]);
#endif
// Save OLD stackFrame state
stackFrame = stackframe_array() + (newStackFrameIndex - 1);
update_stack_frame (stackFrame);
// Push NEW stack frame
stackFrame++;
}
// Increment size of stack frame array
currentThread->stackFrameArraySize++;
// Initialize rest of new stack frame
stackFrame->methodRecord = methodRecord;
stackFrame->monitor = null;
stackFrame->localsBase = get_stack_ptr() + 1;
// Initialize auxiliary global variables (registers)
pc = get_code_ptr(methodRecord);
#if DEBUG_METHODS
printf ("pc set to 0x%X\n", (int) pc);
#endif
init_sp (stackFrame, methodRecord);
update_constant_registers (stackFrame);
//printf ("m %d stack = %d\n", (int) methodRecord->signatureId, (int) (localsBase - stack_array()));
// Check for stack overflow
// (stackTop + methodRecord->maxOperands) >= (stack_array() + STACK_SIZE);
if (is_stack_overflow (methodRecord))
{
#if !FIXED_STACK_SIZE
StackFrame *stackBase;
int i;
// Need at least this many bytes
// int len = (int)(stackTop + methodRecord->maxOperands) - (int)(stack_array()) - HEADER_SIZE;
// Need to compute new array size (as distinct from number of bytes in array).
int newlen = (((int)(stackTop + methodRecord->maxOperands) - (int)(stack_array()) - HEADER_SIZE + 1) / 4) * 3 / 2;
JINT newStackArray = ptr2word(reallocate_array(word2ptr(currentThread->stackArray), newlen));
// If can't allocate new stack, give in!
if (newStackArray == JNULL)
{
#endif
throw_exception (stackOverflowError);
return false;
#if !FIXED_STACK_SIZE
}
// Adjust pointers.
newlen = newStackArray - currentThread->stackArray;
stackBase = stackframe_array();
stackTop = word2ptr(ptr2word(stackTop) + newlen);
localsBase = word2ptr(ptr2word(localsBase) + newlen);
#if DEBUG_MEMORY
printf("thread=%d, stackTop(%d), localsBase(%d)=%d\n", currentThread->threadId, (int)stackTop, (int)localsBase, (int)(*localsBase));
#endif
for (i=currentThread->stackFrameArraySize-1;
i >= 0;
i--)
{
stackBase[i].localsBase = word2ptr(ptr2word(stackBase[i].localsBase) + newlen);
stackBase[i].stackTop = word2ptr(ptr2word(stackBase[i].stackTop) + newlen);
#if DEBUG_MEMORY
printf("stackBase[%d].localsBase(%d) = %d\n", i, (int)stackBase[i].localsBase, (int)(*stackBase[i].localsBase));
#endif
}
// Assign new array
currentThread->stackArray = newStackArray;
#endif
}
return true;
}
/**
* @param classRecord Record for method class.
* @param methodRecord Calle's method record.
* @param retAddr What the PC should be upon return.
* @return true iff the stack frame was pushed.
*/
boolean dispatch_special (MethodRecord *methodRecord, byte *retAddr)
{
/**
* Note: This code is a little tricky, particularly when used with
* a garbage collector. It manipulates the stack frame and in some cases
* may need to perform memory allocation. In all cases we must take care
* to ensure that if an allocation can be made then any live objects
* on the stack must be below the current stack pointer.
* In addition to the above we take great care so that this function can
* be restarted (to allow us to wait for available memory). To enable this
* we avoid making any commitments to changes to global state until both
* stacks have been commited.
*/
#if DEBUG_METHODS
int debug_ctr;
#endif
Object *stackFrameArray;
StackFrame *stackFrame;
StackFrame *stackBase;
int newStackFrameIndex;
STACKWORD *newStackTop;
#if DEBUG_BYTECODE
printf("call method %d ret %x\n", methodRecord - get_method_table(get_class_record(0)), retAddr);
printf ("\n------ dispatch special - %d ------------------\n\n",
methodRecord->signatureId);
#endif
#if DEBUG_METHODS
printf ("dispatch_special: %d, %d\n",
(int) methodRecord, (int) retAddr);
printf ("-- signature id = %d\n", methodRecord->signatureId);
printf ("-- code offset = %d\n", methodRecord->codeOffset);
printf ("-- flags = %d\n", methodRecord->mflags);
printf ("-- num params = %d\n", methodRecord->numParameters);
//printf ("-- stack ptr = %d\n", (int) get_stack_ptr());
//printf ("-- max stack ptr= %d\n", (int) (currentThread->stackArray + (get_array_size(currentThread->stackArray))*2));
#endif
// First deal with the easy case of a native call...
if (is_native (methodRecord))
{
#if DEBUG_METHODS
printf ("-- native\n");
#endif
// WARNING: Once the instruction below has been executed we may have
// references on the stack that are above the stack pointer. If a GC
// gets run when in this state the reference may get collected as
// grabage. This means that any native functions that take a reference
// parameter and that may end up allocating memory *MUST* protect that
// reference before calling the allocator...
pop_words_cur (methodRecord->numParameters);
switch(dispatch_native (methodRecord->signatureId, get_stack_ptr_cur() + 1))
{
case EXEC_RETRY:
// Need to re-start the instruction, so reset the state of the stack
curStackTop += methodRecord->numParameters;
break;
case EXEC_CONTINUE:
// Normal completion return to the requested point.
curPc = retAddr;
break;
case EXEC_RUN:
// We are running new code, curPc will be set. Nothing to do.
break;
case EXEC_EXCEPTION:
// An exception has been thrown. The PC will be set correctly and
// the stack may have been adjusted...
break;
}
// Stack frame not pushed
return false;
}
// Now start to build the new stack frames. We start by placing the
// the new stack pointer below any params. The params will become locals
// in the new frame.
newStackTop = get_stack_ptr_cur() - methodRecord->numParameters;
newStackFrameIndex = (int)(byte)currentThread->stackFrameIndex;
if (newStackFrameIndex >= 255)
{
throw_new_exception (JAVA_LANG_STACKOVERFLOWERROR);
return false;
}
#if DEBUG_METHODS
//for (debug_ctr = 0; debug_ctr < methodRecord->numParameters; debug_ctr++)
// printf ("-- param[%d] = %ld\n", debug_ctr, (long) get_stack_ptr()[debug_ctr+1]);
#endif
stackFrameArray = ref2obj(currentThread->stackFrameArray);
stackBase = (StackFrame *)array_start(stackFrameArray);
// Setup OLD stackframe ready for return
stackFrame = stackBase + (newStackFrameIndex);
stackFrame->stackTop = newStackTop;
stackFrame->pc = retAddr;
// Push NEW stack frame
// Increment size of stack frame array but do not commit to it until we have
// completely built both new stacks.
newStackFrameIndex++;
stackFrame++;
if (((byte *)stackFrame - (byte *)stackBase) >= get_array_length(stackFrameArray))
{
#if FIXED_STACK_SIZE
throw_new_exception (JAVA_LANG_STACKOVERFLOWERROR);
return false;
#else
if (expand_call_stack(currentThread) < 0)
return false;
stackFrame = (StackFrame *)array_start(currentThread->stackFrameArray) + newStackFrameIndex;
#endif
}
// Initialize rest of new stack frame
stackFrame->methodRecord = methodRecord;
stackFrame->monitor = null;
stackFrame->localsBase = newStackTop + 1;
// Allocate space for locals etc.
newStackTop = init_sp(stackFrame, methodRecord);
stackFrame->stackTop = newStackTop;
currentThread->stackFrameIndex = newStackFrameIndex;
// Check for stack overflow
if (is_stack_overflow (newStackTop, methodRecord))
{
#if FIXED_STACK_SIZE
throw_new_exception (JAVA_LANG_STACKOVERFLOWERROR);
return false;
#else
if (expand_value_stack(currentThread, methodRecord->maxOperands+methodRecord->numLocals) < 0)
{
currentThread->stackFrameIndex--;
return false;
}
// NOTE at this point newStackTop is no longer valid!
newStackTop = stackFrame->stackTop;
#endif
}
// All set. So now we can finally commit to the new stack frames
update_constant_registers (stackFrame);
curStackTop = newStackTop;
// and jump to the start of the new code
curPc = get_code_ptr(methodRecord);
return true;
}
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
}
