void DebuggerProxy::processInterrupt(CmdInterrupt &cmd) {
TRACE_RB(2, "DebuggerProxy::processInterrupt\n");
// Do the server-side work for this interrupt, which just notifies the client.
if (!cmd.onServer(*this)) {
TRACE_RB(1, "Failed to send CmdInterrupt to client\n");
Debugger::UsageLog("server", getSandboxId(), "ProxyError",
"Send interrupt");
stopAndThrow();
}
Debugger::UsageLogInterrupt("server", getSandboxId(), cmd);
// Wait for commands from the debugger client and process them. We'll stay
// here until we get a command that should cause the thread to continue.
while (true) {
DebuggerCommandPtr res;
while (!DebuggerCommand::Receive(m_thrift, res,
"DebuggerProxy::processInterrupt()")) {
// we will wait forever until DebuggerClient sends us something
checkStop();
}
checkStop();
if (res) {
TRACE_RB(2, "Proxy got cmd type %d\n", res->getType());
Debugger::UsageLog("server", getSandboxId(),
folly::to<std::string>(res->getType()));
// Any control flow command gets installed here and we continue execution.
m_flow = std::dynamic_pointer_cast<CmdFlowControl>(res);
if (m_flow) {
m_flow->onSetup(*this, cmd);
if (!m_flow->complete()) {
TRACE_RB(2, "Incomplete flow command %d remaining on proxy for "
"further processing\n", m_flow->getType());
if (m_threadMode == Normal) {
// We want the flow command to complete on the thread that
// starts it.
switchThreadMode(Sticky);
}
} else {
// The flow cmd has determined that it is done with its work and
// doesn't need to remain for later processing.
TRACE_RB(2, "Flow command %d completed\n", m_flow->getType());
m_flow.reset();
}
return;
}
if (res->is(DebuggerCommand::KindOfQuit)) {
TRACE_RB(2, "Received quit command\n");
res->onServer(*this); // acknowledge receipt so that client can quit.
stopAndThrow();
}
}
bool cmdFailure = false;
try {
// Perform the server-side work for this command.
if (res) {
if (!res->onServer(*this)) {
TRACE_RB(1, "Failed to execute cmd %d from client\n", res->getType());
Debugger::UsageLog("server", getSandboxId(), "ProxyError",
"Command failed");
cmdFailure = true;
}
} else {
TRACE_RB(1, "Failed to receive cmd from client\n");
Debugger::UsageLog("server", getSandboxId(), "ProxyError",
"Command receive failed");
cmdFailure = true;
}
} catch (const DebuggerException &e) {
throw;
} catch (const std::exception& e) {
Logger::Warning(DEBUGGER_LOG_TAG
"Cmd type %d onServer() threw exception %s", res->getType(), e.what());
Debugger::UsageLog("server", getSandboxId(), "ProxyError",
"Command exception");
cmdFailure = true;
} catch (...) {
Logger::Warning(DEBUGGER_LOG_TAG
"Cmd type %d onServer() threw non standard exception", res->getType());
Debugger::UsageLog("server", getSandboxId(), "ProxyError",
"Command exception");
cmdFailure = true;
}
if (cmdFailure) stopAndThrow();
if (res->shouldExitInterrupt()) return;
}
}
// Handle an interrupt from the VM.
void DebuggerProxy::interrupt(CmdInterrupt &cmd) {
TRACE_RB(2, "DebuggerProxy::interrupt\n");
// Make any breakpoints that have passed breakable again.
setBreakableForBreakpointsNotMatching(cmd);
// At this point we have an interrupt, but we don't know if we're on the
// thread the proxy considers "current".
// NB: BreakPointReached really means we've got control of a VM thread from
// the opcode hook. This could be for a breakpoint, stepping, etc.
// Wait until this thread is the one this proxy wants to debug.
if (!blockUntilOwn(cmd, true)) {
return;
}
// We know we're on the "current" thread, so we can process any active flow
// command, stop if we're at a breakpoint, handle other interrupts, etc.
if (checkFlowBreak(cmd)) {
// We've hit a breakpoint and now need to make sure that breakpoints
// wont be hit again for this site until control leaves this site.
// (Breakpoints can still get hit if control reaches this site during
// a call that is part of this site because the flags are stacked.)
unsetBreakableForBreakpointsMatching(cmd);
while (true) {
try {
// We're about to send the client an interrupt and start
// waiting for commands back from it. Disable signal polling
// during this time, since our protocol requires that only one
// thread talk to the client at a time.
disableSignalPolling();
SCOPE_EXIT { enableSignalPolling(); };
processInterrupt(cmd);
} catch (const DebuggerException &e) {
switchThreadMode(Normal);
throw;
} catch (...) {
assert(false); // no other exceptions should be seen here
switchThreadMode(Normal);
throw;
}
if (cmd.getInterruptType() == PSPEnded) {
switchThreadMode(Normal);
return; // we are done with this thread
}
if (!m_newThread) {
break; // we're not switching threads
}
switchThreadMode(Normal, m_newThread->m_id);
blockUntilOwn(cmd, false);
}
}
if (m_threadMode == Normal) {
Lock lock(this);
m_thread = 0;
notify();
} else if (cmd.getInterruptType() == PSPEnded) {
switchThreadMode(Normal); // we are done with this thread
}
}
// Checks whether the cmd has any breakpoints that match the current Site.
// Also returns true for cmds that should always break, like SessionStarted,
// and returns true when we have special modes setup for, say, breaking on
// RequestEnded, PSPEnded, etc.
bool DebuggerProxy::checkBreakPoints(CmdInterrupt &cmd) {
TRACE(2, "DebuggerProxy::checkBreakPoints\n");
ReadLock lock(m_breakMutex);
return cmd.shouldBreak(*this, m_breakpoints, getRealStackDepth());
}
void CmdNext::onBeginInterrupt(DebuggerProxy& proxy, CmdInterrupt& interrupt) {
TRACE(2, "CmdNext::onBeginInterrupt\n");
assert(!m_complete); // Complete cmds should not be asked to do work.
ActRec *fp = g_context->getFP();
if (!fp) {
// If we have no frame just wait for the next instruction to be interpreted.
m_needsVMInterrupt = true;
return;
}
PC pc = g_context->getPC();
Unit* unit = fp->m_func->unit();
Offset offset = unit->offsetOf(pc);
TRACE(2, "CmdNext: pc %p, opcode %s at '%s' offset %d\n",
pc,
opcodeToName(*reinterpret_cast<const Op*>(pc)),
fp->m_func->fullName()->data(),
offset);
int currentVMDepth = g_context->m_nesting;
int currentStackDepth = proxy.getStackDepth();
TRACE(2, "CmdNext: original depth %d:%d, current depth %d:%d\n",
m_vmDepth, m_stackDepth, currentVMDepth, currentStackDepth);
// Where are we on the stack now vs. when we started? Breaking the answer down
// into distinct variables helps the clarity of the algorithm below.
bool deeper = false;
bool originalDepth = false;
if ((currentVMDepth == m_vmDepth) && (currentStackDepth == m_stackDepth)) {
originalDepth = true;
} else if ((currentVMDepth > m_vmDepth) ||
((currentVMDepth == m_vmDepth) &&
(currentStackDepth > m_stackDepth))) {
deeper = true;
}
m_needsVMInterrupt = false; // Will be set again below if still needed.
// First consider if we've got internal breakpoints setup. These are used when
// we can make an accurate prediction of where execution should flow,
// eventually, and when we want to let the program run normally until we get
// there.
if (hasStepOuts() || hasStepCont()) {
TRACE(2, "CmdNext: checking internal breakpoint(s)\n");
if (atStepOutOffset(unit, offset)) {
if (deeper) return; // Recursion
TRACE(2, "CmdNext: hit step-out\n");
} else if (atStepContOffset(unit, offset)) {
if (m_stepContTag != getResumableTag(fp)) return;
TRACE(2, "CmdNext: hit step-cont\n");
// We're in the continuation we expect. This may be at a
// different stack depth, though, especially if we've moved from
// the original function to the continuation. Update the depth
// accordingly.
if (!originalDepth) {
m_vmDepth = currentVMDepth;
m_stackDepth = currentStackDepth;
deeper = false;
originalDepth = true;
}
} else if (interrupt.getInterruptType() == ExceptionHandler) {
// Entering an exception handler may take us someplace we weren't
// expecting. Adjust internal breakpoints accordingly. First case is easy.
if (deeper) {
TRACE(2, "CmdNext: exception handler, deeper\n");
return;
}
// For step-conts, we ignore handlers at the original level if we're not
// in the original continuation. We don't care about exception handlers
// in continuations being driven at the same level.
if (hasStepCont() && originalDepth &&
(m_stepContTag != getResumableTag(fp))) {
TRACE(2, "CmdNext: exception handler, original depth, wrong cont\n");
return;
}
// Sometimes we have handlers in generated code, i.e., Continuation::next.
// These just help propagate exceptions so ignore those.
if (fp->m_func->line1() == 0) {
TRACE(2, "CmdNext: exception handler, ignoring func with no source\n");
return;
}
TRACE(2, "CmdNext: exception handler altering expected flow\n");
} else {
// We have internal breakpoints setup, but we haven't hit one yet. Keep
// running until we reach one.
TRACE(2, "CmdNext: waiting to hit internal breakpoint...\n");
return;
}
// We've hit one internal breakpoint at a useful place, or decided we don't,
// need them, so we can remove them all now.
cleanupStepOuts();
cleanupStepCont();
}
if (interrupt.getInterruptType() == ExceptionHandler) {
// If we're about to enter an exception handler we turn interrupts on to
// ensure we stop when control reaches the handler. The normal logic below
// will decide if we're done at that point or not.
TRACE(2, "CmdNext: exception handler\n");
removeLocationFilter();
m_needsVMInterrupt = true;
return;
}
if (m_skippingAsyncSuspend) {
m_skippingAsyncSuspend = false;
stepAfterAsyncSuspend();
return;
}
if (deeper) {
TRACE(2, "CmdNext: deeper, setup step out to get back to original line\n");
setupStepOuts();
// We can nuke the entire location filter here since we'll re-install it
// when we get back to the old level. Keeping it installed may be more
// efficient if we were on a large line, but there is a penalty for every
// opcode executed while it's installed and that's bad if there's a lot of
// code called from that line.
removeLocationFilter();
return;
}
if (originalDepth && (m_loc == interrupt.getFileLine())) {
TRACE(2, "CmdNext: not complete, still on same line\n");
stepCurrentLine(interrupt, fp, pc);
return;
}
TRACE(2, "CmdNext: operation complete.\n");
m_complete = (decCount() == 0);
if (!m_complete) {
TRACE(2, "CmdNext: repeat count > 0, start fresh.\n");
onSetup(proxy, interrupt);
}
}
void CmdStep::onSetup(DebuggerProxy &proxy, CmdInterrupt &interrupt) {
assert(!m_complete); // Complete cmds should not be asked to do work.
installLocationFilterForLine(interrupt.getSite());
m_needsVMInterrupt = true;
}
// Checks whether the cmd has any breakpoints that match the current Site.
// Also returns true for cmds that have should always break.
bool DebuggerProxy::checkBreakPoints(CmdInterrupt &cmd) {
TRACE(2, "DebuggerProxy::checkBreakPoints\n");
ReadLock lock(m_breakMutex);
return cmd.shouldBreak(m_breakpoints);
}
// Handle an interrupt from the VM.
void DebuggerProxy::interrupt(CmdInterrupt &cmd) {
TRACE(2, "DebuggerProxy::interrupt\n");
changeBreakPointDepth(cmd);
if (cmd.getInterruptType() == BreakPointReached) {
if (!needInterrupt()) return;
// NB: stepping is represented as a BreakPointReached interrupt.
// Modify m_lastLocFilter to save current location. This will short-circuit
// the work done up in phpDebuggerOpcodeHook() and ensure we don't break on
// this line until we're completely off of it.
InterruptSite *site = cmd.getSite();
if (g_vmContext->m_lastLocFilter) {
g_vmContext->m_lastLocFilter->clear();
} else {
g_vmContext->m_lastLocFilter = new VM::PCFilter();
}
if (debug && Trace::moduleEnabled(Trace::bcinterp, 5)) {
Trace::trace("prepare source loc filter\n");
const VM::OffsetRangeVec& offsets = site->getCurOffsetRange();
for (VM::OffsetRangeVec::const_iterator it = offsets.begin();
it != offsets.end(); ++it) {
Trace::trace("block source loc in %s:%d: unit %p offset [%d, %d)\n",
site->getFile(), site->getLine0(),
site->getUnit(), it->m_base, it->m_past);
}
}
g_vmContext->m_lastLocFilter->addRanges(site->getUnit(),
site->getCurOffsetRange());
// If the breakpoint is not to be processed, we should continue execution.
BreakPointInfoPtr bp = getBreakPointAtCmd(cmd);
if (bp) {
if (!bp->breakable(getRealStackDepth())) {
return;
} else {
bp->unsetBreakable(getRealStackDepth());
}
}
}
// Wait until this thread is the thread this proxy wants to debug.
// NB: breakpoints and control flow checks happen here, too, and return false
// if we're not done with the flow, or not at a breakpoint, etc.
if (!blockUntilOwn(cmd, true)) {
return;
}
if (processFlowBreak(cmd)) {
while (true) {
try {
Lock lock(m_signalMutex);
m_signum = CmdSignal::SignalNone;
processInterrupt(cmd);
} catch (const DebuggerException &e) {
switchThreadMode(Normal);
throw;
} catch (...) {
assert(false); // no other exceptions should be seen here
switchThreadMode(Normal);
throw;
}
if (cmd.getInterruptType() == PSPEnded) {
switchThreadMode(Normal);
return; // we are done with this thread
}
if (!m_newThread) {
break; // we're not switching threads
}
switchThreadMode(Normal, m_newThread->m_id);
blockUntilOwn(cmd, false);
}
}
if (m_threadMode == Normal) {
Lock lock(this);
m_thread = 0;
notify();
} else if (cmd.getInterruptType() == PSPEnded) {
switchThreadMode(Normal); // we are done with this thread
}
}
