// 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 // won't 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) { TRACE(2, "DebuggerException from processInterrupt!\n"); switchThreadMode(Normal); throw; } catch (...) { TRACE(2, "Unknown exception from processInterrupt!\n"); assertx(false); // no other exceptions should be seen here switchThreadMode(Normal); throw; } if (cmd.getInterruptType() == PSPEnded) break; if (!m_newThread) break; // we're not switching threads switchThreadMode(Normal, m_newThread->m_id); m_newThread.reset(); blockUntilOwn(cmd, false); } } if ((m_threadMode == Normal) || (cmd.getInterruptType() == PSPEnded)) { // If the thread mode is Normal we let other threads with // interrupts go ahead and process them. We also do this when the // thread is at PSPEnded because the thread is done. switchThreadMode(Normal); } }
std::string DebuggerProxy::requestAuthToken() { Lock lock(m_signalMutex); TRACE_RB(2, "DebuggerProxy::requestauthToken: sending auth request\n"); // Try to use the current sandbox's path, defaulting to the path from // DebuggerDefaultSandboxPath if the current sandbox path is empty. auto sandboxPath = getSandbox().m_path; if (sandboxPath.empty()) { sandboxPath = RuntimeOption::DebuggerDefaultSandboxPath; } CmdAuth cmd; cmd.setSandboxPath(sandboxPath); if (!cmd.onServer(*this)) { TRACE_RB(2, "DebuggerProxy::requestAuthToken: " "Failed to send CmdAuth to client\n"); return ""; } DebuggerCommandPtr res; while (!DebuggerCommand::Receive(m_thrift, res, "DebuggerProxy::requestAuthToken()")) { checkStop(); } if (!res) { TRACE_RB(2, "DebuggerProxy::requestAuthToken: " "Failed to get CmdAuth back from client\n"); return ""; } auto token = std::dynamic_pointer_cast<CmdAuth>(res); if (!token) { TRACE_RB(2, "DebuggerProxy::requestAuthToken: " "bad response from token request: %d", res->getType()); return ""; } return token->getToken(); }
// Primary entrypoint for the debugger from the VM. Called in response to a host // of VM events that the debugger is interested in. The debugger will execute // any logic needed to handle the event, and will block below this to wait for // and process more commands from the debugger client. This function will only // return when the debugger is letting the thread continue execution, e.g., for // flow control command like continue, next, etc. void Debugger::Interrupt(int type, const char *program, InterruptSite *site /* = NULL */, const char *error /* = NULL */) { assert(RuntimeOption::EnableDebugger); TRACE_RB(2, "Debugger::Interrupt type %d\n", type); DebuggerProxyPtr proxy = GetProxy(); if (proxy) { TRACE(3, "proxy != null\n"); RequestInjectionData &rjdata = ThreadInfo::s_threadInfo->m_reqInjectionData; // The proxy will only service an interrupt if we've previously setup some // form of flow control command (steps, breakpoints, etc.) or if it's // an interrupt related to something like the session or request. if (proxy->needInterrupt() || type != BreakPointReached) { // Interrupts may execute some PHP code, causing another interruption. std::stack<void *> &interrupts = rjdata.interrupts; CmdInterrupt cmd((InterruptType)type, program, site, error); interrupts.push(&cmd); proxy->interrupt(cmd); interrupts.pop(); } // Some cmds require us to interpret all instructions until the cmd // completes. Setting this will ensure we stay out of JIT code and in the // interpreter so phpDebuggerOpcodeHook has a chance to work. rjdata.setDebuggerIntr(proxy->needVMInterrupts()); } else { TRACE(3, "proxy == null\n"); // Debugger clients are disconnected abnormally, or this sandbox is not // being debugged. if (type == SessionStarted || type == SessionEnded) { // For command line programs, we need this exception to exit from // the infinite execution loop. throw DebuggerClientExitException(); } } }
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 Object &o) { Logger::Warning(DEBUGGER_LOG_TAG "Cmd type %d onServer() threw a php exception %s", res->getType(), o->getVMClass()->name()->data()); Debugger::UsageLog("server", getSandboxId(), "ProxyError", "Command exception"); cmdFailure = true; } 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; } }
// This gets it's own thread, and polls the client once per second to see if // there is a signal, i.e., if the user has pressed Ctrl-C, etc. If there is a // signal, it is passed as an interrupt to the proxy in an attempt to get other // threads in the sandbox to stop. // // If another thread in the sandbox fails to stop and consume the signal then // it will be passed to the dummy sandbox instead. void DebuggerProxy::pollSignal() { TRACE_RB(2, "DebuggerProxy::pollSignal: starting\n"); int signalTimeout = RuntimeOption::DebuggerSignalTimeout; while (!m_stopped) { sleep(1); // Block any threads that might be interrupting from communicating with the // client until we're done with this poll. Lock lock(m_signalMutex); // After DebuggerSignalTimeout seconds that no active thread picks // up the signal, we send it to dummy sandbox. if ((m_signum != CmdSignal::SignalNone) && m_dummySandbox && (--signalTimeout <= 0)) { TRACE_RB(2, "DebuggerProxy::pollSignal: sending to dummy sandbox\n"); m_dummySandbox->notifySignal(m_signum); m_signum = CmdSignal::SignalNone; } // Don't actually poll if another thread is already in a command // processing loop with the client. if (!m_okayToPoll) continue; // Send CmdSignal over to the client and wait for a response. CmdSignal cmd; if (!cmd.onServer(*this)) { TRACE_RB(2, "DebuggerProxy::pollSignal: " "Failed to send CmdSignal to client\n"); break; } // We've sent the client a command, and we expect an immediate // response. Wait 10 times to give it a chance on especially // overloaded computers. DebuggerCommandPtr res; for (int i = 0; i < 10; i++) { if (DebuggerCommand::Receive(m_thrift, res, "DebuggerProxy::pollSignal()")) break; if (m_stopped) { TRACE_RB(2, "DebuggerProxy::pollSignal: " "signal thread asked to stop while waiting " "for CmdSignal back from the client\n"); break; } } if (!res) { if (!m_stopped) { TRACE_RB(2, "DebuggerProxy::pollSignal: " "Failed to get CmdSignal back from client\n"); } break; } auto sig = std::dynamic_pointer_cast<CmdSignal>(res); if (!sig) { TRACE_RB(2, "DebuggerProxy::pollSignal: " "bad response from signal polling: %d", res->getType()); break; } auto newSignum = sig->getSignal(); if (newSignum != CmdSignal::SignalNone) { TRACE_RB(2, "DebuggerProxy::pollSignal: " "got interrupt signal from client\n"); m_signum = newSignum; signalTimeout = RuntimeOption::DebuggerSignalTimeout; Debugger::RequestInterrupt(shared_from_this()); } } if (!m_stopped) { // We've noticed that the socket has closed. Stop and destory this proxy. TRACE_RB(2, "DebuggerProxy::pollSignal: " "lost communication with the client, stopping proxy\n"); Debugger::UsageLog("server", getSandboxId(), "ProxyError", "Signal poll"); stop(); } TRACE_RB(2, "DebuggerProxy::pollSignal: ended\n"); }
// Returns false on timeout, true when data has been read even if that data // didn't form a usable command. Is there is no usable command, cmd is null. bool DebuggerCommand::Receive(DebuggerThriftBuffer &thrift, DebuggerCommandPtr &cmd, const char *caller) { TRACE(5, "DebuggerCommand::Receive\n"); cmd.reset(); struct pollfd fds[1]; fds[0].fd = thrift.getSocket()->fd(); fds[0].events = POLLIN|POLLERR|POLLHUP; int ret = poll(fds, 1, POLLING_SECONDS * 1000); if (ret == 0) return false; // Timeout if (ret == -1) { auto errorNumber = errno; // Just in case TRACE_RB changes errno TRACE_RB(1, "DebuggerCommand::Receive: error %d\n", errorNumber); return errorNumber != EINTR; // Treat signals as timeouts } // If we don't have any data to read (POLLIN) then we're done. If we // do have data we'll attempt to read and decode it below, even if // there are other error bits set. if (!(fds[0].revents & POLLIN)) { TRACE_RB(1, "DebuggerCommand::Receive: revents %d\n", fds[0].revents); return true; } int32_t type; std::string clsname; try { thrift.reset(true); thrift.read(type); thrift.read(clsname); } catch (...) { // Note: this error case is difficult to test. But, it's exactly the same // as the error noted below. Make sure to keep handling of both of these // errors in sync. TRACE_RB(1, "%s: socket error receiving command", caller); return true; } TRACE(1, "DebuggerCommand::Receive: got cmd of type %d\n", type); // not all commands are here, as not all commands need to be sent over wire switch (type) { case KindOfBreak : cmd = DebuggerCommandPtr(new CmdBreak ()); break; case KindOfContinue : cmd = DebuggerCommandPtr(new CmdContinue ()); break; case KindOfDown : cmd = DebuggerCommandPtr(new CmdDown ()); break; case KindOfException: cmd = DebuggerCommandPtr(new CmdException()); break; case KindOfFrame : cmd = DebuggerCommandPtr(new CmdFrame ()); break; case KindOfGlobal : cmd = DebuggerCommandPtr(new CmdGlobal ()); break; case KindOfInfo : cmd = DebuggerCommandPtr(new CmdInfo ()); break; case KindOfConstant : cmd = DebuggerCommandPtr(new CmdConstant ()); break; case KindOfList : cmd = DebuggerCommandPtr(new CmdList ()); break; case KindOfMachine : cmd = DebuggerCommandPtr(new CmdMachine ()); break; case KindOfNext : cmd = DebuggerCommandPtr(new CmdNext ()); break; case KindOfOut : cmd = DebuggerCommandPtr(new CmdOut ()); break; case KindOfPrint : cmd = DebuggerCommandPtr(new CmdPrint ()); break; case KindOfQuit : cmd = DebuggerCommandPtr(new CmdQuit ()); break; case KindOfRun : cmd = DebuggerCommandPtr(new CmdRun ()); break; case KindOfStep : cmd = DebuggerCommandPtr(new CmdStep ()); break; case KindOfThread : cmd = DebuggerCommandPtr(new CmdThread ()); break; case KindOfUp : cmd = DebuggerCommandPtr(new CmdUp ()); break; case KindOfVariable : cmd = DebuggerCommandPtr(new CmdVariable ()); break; case KindOfVariableAsync : cmd = DebuggerCommandPtr(new CmdVariable (KindOfVariableAsync)); break; case KindOfWhere : cmd = DebuggerCommandPtr(new CmdWhere ()); break; case KindOfWhereAsync: cmd = DebuggerCommandPtr(new CmdWhere(KindOfWhereAsync)); break; case KindOfEval : cmd = DebuggerCommandPtr(new CmdEval ()); break; case KindOfInterrupt: cmd = DebuggerCommandPtr(new CmdInterrupt()); break; case KindOfSignal : cmd = DebuggerCommandPtr(new CmdSignal ()); break; case KindOfShell : cmd = DebuggerCommandPtr(new CmdShell ()); break; case KindOfInternalTesting : cmd = DebuggerCommandPtr(new CmdInternalTesting()); break; case KindOfExtended: { assert(!clsname.empty()); cmd = CmdExtended::CreateExtendedCommand(clsname); assert(cmd); break; } default: TRACE_RB(1, "%s: received bad cmd type: %d", caller, type); cmd.reset(); return true; } if (!cmd->recv(thrift)) { // Note: this error case is easily tested, and we have a test for it. But // the error case noted above is quite difficult to test. Keep these two // in sync. TRACE_RB(1, "%s: socket error receiving command", caller); cmd.reset(); } return true; }