1 //===- KillTheDoctor - Prevent Dr. Watson from stopping tests ---*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This program provides an extremely hacky way to stop Dr. Watson from starting 10 // due to unhandled exceptions in child processes. 11 // 12 // This simply starts the program named in the first positional argument with 13 // the arguments following it under a debugger. All this debugger does is catch 14 // any unhandled exceptions thrown in the child process and close the program 15 // (and hopefully tells someone about it). 16 // 17 // This also provides another really hacky method to prevent assert dialog boxes 18 // from popping up. When --no-user32 is passed, if any process loads user32.dll, 19 // we assume it is trying to call MessageBoxEx and terminate it. The proper way 20 // to do this would be to actually set a break point, but there's quite a bit 21 // of code involved to get the address of MessageBoxEx in the remote process's 22 // address space due to Address space layout randomization (ASLR). This can be 23 // added if it's ever actually needed. 24 // 25 // If the subprocess exits for any reason other than successful termination, -1 26 // is returned. If the process exits normally the value it returned is returned. 27 // 28 // I hate Windows. 29 // 30 //===----------------------------------------------------------------------===// 31 32 #include "llvm/ADT/STLExtras.h" 33 #include "llvm/ADT/SmallString.h" 34 #include "llvm/ADT/SmallVector.h" 35 #include "llvm/ADT/StringExtras.h" 36 #include "llvm/ADT/StringRef.h" 37 #include "llvm/ADT/Twine.h" 38 #include "llvm/Support/CommandLine.h" 39 #include "llvm/Support/ManagedStatic.h" 40 #include "llvm/Support/Path.h" 41 #include "llvm/Support/PrettyStackTrace.h" 42 #include "llvm/Support/Signals.h" 43 #include "llvm/Support/WindowsError.h" 44 #include "llvm/Support/raw_ostream.h" 45 #include "llvm/Support/type_traits.h" 46 #include <algorithm> 47 #include <cerrno> 48 #include <cstdlib> 49 #include <map> 50 #include <string> 51 #include <system_error> 52 53 // These includes must be last. 54 #include <windows.h> 55 #include <winerror.h> 56 #include <dbghelp.h> 57 #include <psapi.h> 58 59 using namespace llvm; 60 61 #undef max 62 63 namespace { 64 cl::opt<std::string> ProgramToRun(cl::Positional, 65 cl::desc("<program to run>")); 66 cl::list<std::string> Argv(cl::ConsumeAfter, 67 cl::desc("<program arguments>...")); 68 cl::opt<bool> TraceExecution("x", 69 cl::desc("Print detailed output about what is being run to stderr.")); 70 cl::opt<unsigned> Timeout("t", cl::init(0), 71 cl::desc("Set maximum runtime in seconds. Defaults to infinite.")); 72 cl::opt<bool> NoUser32("no-user32", 73 cl::desc("Terminate process if it loads user32.dll.")); 74 75 StringRef ToolName; 76 77 template <typename HandleType> 78 class ScopedHandle { 79 typedef typename HandleType::handle_type handle_type; 80 81 handle_type Handle; 82 83 public: 84 ScopedHandle() 85 : Handle(HandleType::GetInvalidHandle()) {} 86 87 explicit ScopedHandle(handle_type handle) 88 : Handle(handle) {} 89 90 ~ScopedHandle() { 91 HandleType::Destruct(Handle); 92 } 93 94 ScopedHandle& operator=(handle_type handle) { 95 // Cleanup current handle. 96 if (!HandleType::isValid(Handle)) 97 HandleType::Destruct(Handle); 98 Handle = handle; 99 return *this; 100 } 101 102 operator bool() const { 103 return HandleType::isValid(Handle); 104 } 105 106 operator handle_type() { 107 return Handle; 108 } 109 }; 110 111 // This implements the most common handle in the Windows API. 112 struct CommonHandle { 113 typedef HANDLE handle_type; 114 115 static handle_type GetInvalidHandle() { 116 return INVALID_HANDLE_VALUE; 117 } 118 119 static void Destruct(handle_type Handle) { 120 ::CloseHandle(Handle); 121 } 122 123 static bool isValid(handle_type Handle) { 124 return Handle != GetInvalidHandle(); 125 } 126 }; 127 128 struct FileMappingHandle { 129 typedef HANDLE handle_type; 130 131 static handle_type GetInvalidHandle() { 132 return NULL; 133 } 134 135 static void Destruct(handle_type Handle) { 136 ::CloseHandle(Handle); 137 } 138 139 static bool isValid(handle_type Handle) { 140 return Handle != GetInvalidHandle(); 141 } 142 }; 143 144 struct MappedViewOfFileHandle { 145 typedef LPVOID handle_type; 146 147 static handle_type GetInvalidHandle() { 148 return NULL; 149 } 150 151 static void Destruct(handle_type Handle) { 152 ::UnmapViewOfFile(Handle); 153 } 154 155 static bool isValid(handle_type Handle) { 156 return Handle != GetInvalidHandle(); 157 } 158 }; 159 160 struct ProcessHandle : CommonHandle {}; 161 struct ThreadHandle : CommonHandle {}; 162 struct TokenHandle : CommonHandle {}; 163 struct FileHandle : CommonHandle {}; 164 165 typedef ScopedHandle<FileMappingHandle> FileMappingScopedHandle; 166 typedef ScopedHandle<MappedViewOfFileHandle> MappedViewOfFileScopedHandle; 167 typedef ScopedHandle<ProcessHandle> ProcessScopedHandle; 168 typedef ScopedHandle<ThreadHandle> ThreadScopedHandle; 169 typedef ScopedHandle<TokenHandle> TokenScopedHandle; 170 typedef ScopedHandle<FileHandle> FileScopedHandle; 171 } 172 173 static std::error_code windows_error(DWORD E) { return mapWindowsError(E); } 174 175 static std::error_code GetFileNameFromHandle(HANDLE FileHandle, 176 std::string &Name) { 177 char Filename[MAX_PATH+1]; 178 bool Success = false; 179 Name.clear(); 180 181 // Get the file size. 182 LARGE_INTEGER FileSize; 183 Success = ::GetFileSizeEx(FileHandle, &FileSize); 184 185 if (!Success) 186 return windows_error(::GetLastError()); 187 188 // Create a file mapping object. 189 FileMappingScopedHandle FileMapping( 190 ::CreateFileMappingA(FileHandle, 191 NULL, 192 PAGE_READONLY, 193 0, 194 1, 195 NULL)); 196 197 if (!FileMapping) 198 return windows_error(::GetLastError()); 199 200 // Create a file mapping to get the file name. 201 MappedViewOfFileScopedHandle MappedFile( 202 ::MapViewOfFile(FileMapping, FILE_MAP_READ, 0, 0, 1)); 203 204 if (!MappedFile) 205 return windows_error(::GetLastError()); 206 207 Success = ::GetMappedFileNameA(::GetCurrentProcess(), MappedFile, Filename, 208 std::size(Filename) - 1); 209 210 if (!Success) 211 return windows_error(::GetLastError()); 212 else { 213 Name = Filename; 214 return std::error_code(); 215 } 216 } 217 218 /// Find program using shell lookup rules. 219 /// @param Program This is either an absolute path, relative path, or simple a 220 /// program name. Look in PATH for any programs that match. If no 221 /// extension is present, try all extensions in PATHEXT. 222 /// @return If ec == errc::success, The absolute path to the program. Otherwise 223 /// the return value is undefined. 224 static std::string FindProgram(const std::string &Program, 225 std::error_code &ec) { 226 char PathName[MAX_PATH + 1]; 227 typedef SmallVector<StringRef, 12> pathext_t; 228 pathext_t pathext; 229 // Check for the program without an extension (in case it already has one). 230 pathext.push_back(""); 231 SplitString(std::getenv("PATHEXT"), pathext, ";"); 232 233 for (pathext_t::iterator i = pathext.begin(), e = pathext.end(); i != e; ++i){ 234 SmallString<5> ext; 235 for (std::size_t ii = 0, e = i->size(); ii != e; ++ii) 236 ext.push_back(::tolower((*i)[ii])); 237 LPCSTR Extension = NULL; 238 if (ext.size() && ext[0] == '.') 239 Extension = ext.c_str(); 240 DWORD length = ::SearchPathA(NULL, Program.c_str(), Extension, 241 std::size(PathName), PathName, NULL); 242 if (length == 0) 243 ec = windows_error(::GetLastError()); 244 else if (length > std::size(PathName)) { 245 // This may have been the file, return with error. 246 ec = windows_error(ERROR_BUFFER_OVERFLOW); 247 break; 248 } else { 249 // We found the path! Return it. 250 ec = std::error_code(); 251 break; 252 } 253 } 254 255 // Make sure PathName is valid. 256 PathName[MAX_PATH] = 0; 257 return PathName; 258 } 259 260 static StringRef ExceptionCodeToString(DWORD ExceptionCode) { 261 switch(ExceptionCode) { 262 case EXCEPTION_ACCESS_VIOLATION: return "EXCEPTION_ACCESS_VIOLATION"; 263 case EXCEPTION_ARRAY_BOUNDS_EXCEEDED: 264 return "EXCEPTION_ARRAY_BOUNDS_EXCEEDED"; 265 case EXCEPTION_BREAKPOINT: return "EXCEPTION_BREAKPOINT"; 266 case EXCEPTION_DATATYPE_MISALIGNMENT: 267 return "EXCEPTION_DATATYPE_MISALIGNMENT"; 268 case EXCEPTION_FLT_DENORMAL_OPERAND: return "EXCEPTION_FLT_DENORMAL_OPERAND"; 269 case EXCEPTION_FLT_DIVIDE_BY_ZERO: return "EXCEPTION_FLT_DIVIDE_BY_ZERO"; 270 case EXCEPTION_FLT_INEXACT_RESULT: return "EXCEPTION_FLT_INEXACT_RESULT"; 271 case EXCEPTION_FLT_INVALID_OPERATION: 272 return "EXCEPTION_FLT_INVALID_OPERATION"; 273 case EXCEPTION_FLT_OVERFLOW: return "EXCEPTION_FLT_OVERFLOW"; 274 case EXCEPTION_FLT_STACK_CHECK: return "EXCEPTION_FLT_STACK_CHECK"; 275 case EXCEPTION_FLT_UNDERFLOW: return "EXCEPTION_FLT_UNDERFLOW"; 276 case EXCEPTION_ILLEGAL_INSTRUCTION: return "EXCEPTION_ILLEGAL_INSTRUCTION"; 277 case EXCEPTION_IN_PAGE_ERROR: return "EXCEPTION_IN_PAGE_ERROR"; 278 case EXCEPTION_INT_DIVIDE_BY_ZERO: return "EXCEPTION_INT_DIVIDE_BY_ZERO"; 279 case EXCEPTION_INT_OVERFLOW: return "EXCEPTION_INT_OVERFLOW"; 280 case EXCEPTION_INVALID_DISPOSITION: return "EXCEPTION_INVALID_DISPOSITION"; 281 case EXCEPTION_NONCONTINUABLE_EXCEPTION: 282 return "EXCEPTION_NONCONTINUABLE_EXCEPTION"; 283 case EXCEPTION_PRIV_INSTRUCTION: return "EXCEPTION_PRIV_INSTRUCTION"; 284 case EXCEPTION_SINGLE_STEP: return "EXCEPTION_SINGLE_STEP"; 285 case EXCEPTION_STACK_OVERFLOW: return "EXCEPTION_STACK_OVERFLOW"; 286 default: return "<unknown>"; 287 } 288 } 289 290 int main(int argc, char **argv) { 291 // Print a stack trace if we signal out. 292 sys::PrintStackTraceOnErrorSignal(argv[0]); 293 PrettyStackTraceProgram X(argc, argv); 294 llvm_shutdown_obj Y; // Call llvm_shutdown() on exit. 295 296 ToolName = argv[0]; 297 298 cl::ParseCommandLineOptions(argc, argv, "Dr. Watson Assassin.\n"); 299 if (ProgramToRun.size() == 0) { 300 cl::PrintHelpMessage(); 301 return -1; 302 } 303 304 if (Timeout > std::numeric_limits<uint32_t>::max() / 1000) { 305 errs() << ToolName << ": Timeout value too large, must be less than: " 306 << std::numeric_limits<uint32_t>::max() / 1000 307 << '\n'; 308 return -1; 309 } 310 311 std::string CommandLine(ProgramToRun); 312 313 std::error_code ec; 314 ProgramToRun = FindProgram(ProgramToRun, ec); 315 if (ec) { 316 errs() << ToolName << ": Failed to find program: '" << CommandLine 317 << "': " << ec.message() << '\n'; 318 return -1; 319 } 320 321 if (TraceExecution) 322 errs() << ToolName << ": Found Program: " << ProgramToRun << '\n'; 323 324 for (const std::string &Arg : Argv) { 325 CommandLine.push_back(' '); 326 CommandLine.append(Arg); 327 } 328 329 if (TraceExecution) 330 errs() << ToolName << ": Program Image Path: " << ProgramToRun << '\n' 331 << ToolName << ": Command Line: " << CommandLine << '\n'; 332 333 STARTUPINFOA StartupInfo; 334 PROCESS_INFORMATION ProcessInfo; 335 std::memset(&StartupInfo, 0, sizeof(StartupInfo)); 336 StartupInfo.cb = sizeof(StartupInfo); 337 std::memset(&ProcessInfo, 0, sizeof(ProcessInfo)); 338 339 // Set error mode to not display any message boxes. The child process inherits 340 // this. 341 ::SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOGPFAULTERRORBOX); 342 ::_set_error_mode(_OUT_TO_STDERR); 343 344 BOOL success = ::CreateProcessA(ProgramToRun.c_str(), 345 const_cast<LPSTR>(CommandLine.c_str()), 346 NULL, 347 NULL, 348 FALSE, 349 DEBUG_PROCESS, 350 NULL, 351 NULL, 352 &StartupInfo, 353 &ProcessInfo); 354 if (!success) { 355 errs() << ToolName << ": Failed to run program: '" << ProgramToRun << "': " 356 << std::error_code(windows_error(::GetLastError())).message() 357 << '\n'; 358 return -1; 359 } 360 361 // Make sure ::CloseHandle is called on exit. 362 std::map<DWORD, HANDLE> ProcessIDToHandle; 363 364 DEBUG_EVENT DebugEvent; 365 std::memset(&DebugEvent, 0, sizeof(DebugEvent)); 366 DWORD dwContinueStatus = DBG_CONTINUE; 367 368 // Run the program under the debugger until either it exits, or throws an 369 // exception. 370 if (TraceExecution) 371 errs() << ToolName << ": Debugging...\n"; 372 373 while(true) { 374 DWORD TimeLeft = INFINITE; 375 if (Timeout > 0) { 376 FILETIME CreationTime, ExitTime, KernelTime, UserTime; 377 ULARGE_INTEGER a, b; 378 success = ::GetProcessTimes(ProcessInfo.hProcess, 379 &CreationTime, 380 &ExitTime, 381 &KernelTime, 382 &UserTime); 383 if (!success) { 384 ec = windows_error(::GetLastError()); 385 386 errs() << ToolName << ": Failed to get process times: " 387 << ec.message() << '\n'; 388 return -1; 389 } 390 a.LowPart = KernelTime.dwLowDateTime; 391 a.HighPart = KernelTime.dwHighDateTime; 392 b.LowPart = UserTime.dwLowDateTime; 393 b.HighPart = UserTime.dwHighDateTime; 394 // Convert 100-nanosecond units to milliseconds. 395 uint64_t TotalTimeMiliseconds = (a.QuadPart + b.QuadPart) / 10000; 396 // Handle the case where the process has been running for more than 49 397 // days. 398 if (TotalTimeMiliseconds > std::numeric_limits<uint32_t>::max()) { 399 errs() << ToolName << ": Timeout Failed: Process has been running for" 400 "more than 49 days.\n"; 401 return -1; 402 } 403 404 // We check with > instead of using Timeleft because if 405 // TotalTimeMiliseconds is greater than Timeout * 1000, TimeLeft would 406 // underflow. 407 if (TotalTimeMiliseconds > (Timeout * 1000)) { 408 errs() << ToolName << ": Process timed out.\n"; 409 ::TerminateProcess(ProcessInfo.hProcess, -1); 410 // Otherwise other stuff starts failing... 411 return -1; 412 } 413 414 TimeLeft = (Timeout * 1000) - static_cast<uint32_t>(TotalTimeMiliseconds); 415 } 416 success = WaitForDebugEvent(&DebugEvent, TimeLeft); 417 418 if (!success) { 419 DWORD LastError = ::GetLastError(); 420 ec = windows_error(LastError); 421 422 if (LastError == ERROR_SEM_TIMEOUT || LastError == WSAETIMEDOUT) { 423 errs() << ToolName << ": Process timed out.\n"; 424 ::TerminateProcess(ProcessInfo.hProcess, -1); 425 // Otherwise other stuff starts failing... 426 return -1; 427 } 428 429 errs() << ToolName << ": Failed to wait for debug event in program: '" 430 << ProgramToRun << "': " << ec.message() << '\n'; 431 return -1; 432 } 433 434 switch(DebugEvent.dwDebugEventCode) { 435 case CREATE_PROCESS_DEBUG_EVENT: 436 // Make sure we remove the handle on exit. 437 if (TraceExecution) 438 errs() << ToolName << ": Debug Event: CREATE_PROCESS_DEBUG_EVENT\n"; 439 ProcessIDToHandle[DebugEvent.dwProcessId] = 440 DebugEvent.u.CreateProcessInfo.hProcess; 441 ::CloseHandle(DebugEvent.u.CreateProcessInfo.hFile); 442 break; 443 case EXIT_PROCESS_DEBUG_EVENT: { 444 if (TraceExecution) 445 errs() << ToolName << ": Debug Event: EXIT_PROCESS_DEBUG_EVENT\n"; 446 447 // If this is the process we originally created, exit with its exit 448 // code. 449 if (DebugEvent.dwProcessId == ProcessInfo.dwProcessId) 450 return DebugEvent.u.ExitProcess.dwExitCode; 451 452 // Otherwise cleanup any resources we have for it. 453 std::map<DWORD, HANDLE>::iterator ExitingProcess = 454 ProcessIDToHandle.find(DebugEvent.dwProcessId); 455 if (ExitingProcess == ProcessIDToHandle.end()) { 456 errs() << ToolName << ": Got unknown process id!\n"; 457 return -1; 458 } 459 ::CloseHandle(ExitingProcess->second); 460 ProcessIDToHandle.erase(ExitingProcess); 461 } 462 break; 463 case CREATE_THREAD_DEBUG_EVENT: 464 ::CloseHandle(DebugEvent.u.CreateThread.hThread); 465 break; 466 case LOAD_DLL_DEBUG_EVENT: { 467 // Cleanup the file handle. 468 FileScopedHandle DLLFile(DebugEvent.u.LoadDll.hFile); 469 std::string DLLName; 470 ec = GetFileNameFromHandle(DLLFile, DLLName); 471 if (ec) { 472 DLLName = "<failed to get file name from file handle> : "; 473 DLLName += ec.message(); 474 } 475 if (TraceExecution) { 476 errs() << ToolName << ": Debug Event: LOAD_DLL_DEBUG_EVENT\n"; 477 errs().indent(ToolName.size()) << ": DLL Name : " << DLLName << '\n'; 478 } 479 480 if (NoUser32 && sys::path::stem(DLLName) == "user32") { 481 // Program is loading user32.dll, in the applications we are testing, 482 // this only happens if an assert has fired. By now the message has 483 // already been printed, so simply close the program. 484 errs() << ToolName << ": user32.dll loaded!\n"; 485 errs().indent(ToolName.size()) 486 << ": This probably means that assert was called. Closing " 487 "program to prevent message box from popping up.\n"; 488 dwContinueStatus = DBG_CONTINUE; 489 ::TerminateProcess(ProcessIDToHandle[DebugEvent.dwProcessId], -1); 490 return -1; 491 } 492 } 493 break; 494 case EXCEPTION_DEBUG_EVENT: { 495 // Close the application if this exception will not be handled by the 496 // child application. 497 if (TraceExecution) 498 errs() << ToolName << ": Debug Event: EXCEPTION_DEBUG_EVENT\n"; 499 500 EXCEPTION_DEBUG_INFO &Exception = DebugEvent.u.Exception; 501 if (Exception.dwFirstChance > 0) { 502 if (TraceExecution) { 503 errs().indent(ToolName.size()) << ": Debug Info : "; 504 errs() << "First chance exception at " 505 << Exception.ExceptionRecord.ExceptionAddress 506 << ", exception code: " 507 << ExceptionCodeToString( 508 Exception.ExceptionRecord.ExceptionCode) 509 << " (" << Exception.ExceptionRecord.ExceptionCode << ")\n"; 510 } 511 dwContinueStatus = DBG_EXCEPTION_NOT_HANDLED; 512 } else { 513 errs() << ToolName << ": Unhandled exception in: " << ProgramToRun 514 << "!\n"; 515 errs().indent(ToolName.size()) << ": location: "; 516 errs() << Exception.ExceptionRecord.ExceptionAddress 517 << ", exception code: " 518 << ExceptionCodeToString( 519 Exception.ExceptionRecord.ExceptionCode) 520 << " (" << Exception.ExceptionRecord.ExceptionCode 521 << ")\n"; 522 dwContinueStatus = DBG_CONTINUE; 523 ::TerminateProcess(ProcessIDToHandle[DebugEvent.dwProcessId], -1); 524 return -1; 525 } 526 } 527 break; 528 default: 529 // Do nothing. 530 if (TraceExecution) 531 errs() << ToolName << ": Debug Event: <unknown>\n"; 532 break; 533 } 534 535 success = ContinueDebugEvent(DebugEvent.dwProcessId, 536 DebugEvent.dwThreadId, 537 dwContinueStatus); 538 if (!success) { 539 ec = windows_error(::GetLastError()); 540 errs() << ToolName << ": Failed to continue debugging program: '" 541 << ProgramToRun << "': " << ec.message() << '\n'; 542 return -1; 543 } 544 545 dwContinueStatus = DBG_CONTINUE; 546 } 547 548 assert(0 && "Fell out of debug loop. This shouldn't be possible!"); 549 return -1; 550 } 551