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:
ScopedHandle()84 ScopedHandle()
85 : Handle(HandleType::GetInvalidHandle()) {}
86
ScopedHandle(handle_type handle)87 explicit ScopedHandle(handle_type handle)
88 : Handle(handle) {}
89
~ScopedHandle()90 ~ScopedHandle() {
91 HandleType::Destruct(Handle);
92 }
93
operator =(handle_type handle)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
operator bool() const102 operator bool() const {
103 return HandleType::isValid(Handle);
104 }
105
operator handle_type()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
GetInvalidHandle__anon41724efc0111::CommonHandle115 static handle_type GetInvalidHandle() {
116 return INVALID_HANDLE_VALUE;
117 }
118
Destruct__anon41724efc0111::CommonHandle119 static void Destruct(handle_type Handle) {
120 ::CloseHandle(Handle);
121 }
122
isValid__anon41724efc0111::CommonHandle123 static bool isValid(handle_type Handle) {
124 return Handle != GetInvalidHandle();
125 }
126 };
127
128 struct FileMappingHandle {
129 typedef HANDLE handle_type;
130
GetInvalidHandle__anon41724efc0111::FileMappingHandle131 static handle_type GetInvalidHandle() {
132 return NULL;
133 }
134
Destruct__anon41724efc0111::FileMappingHandle135 static void Destruct(handle_type Handle) {
136 ::CloseHandle(Handle);
137 }
138
isValid__anon41724efc0111::FileMappingHandle139 static bool isValid(handle_type Handle) {
140 return Handle != GetInvalidHandle();
141 }
142 };
143
144 struct MappedViewOfFileHandle {
145 typedef LPVOID handle_type;
146
GetInvalidHandle__anon41724efc0111::MappedViewOfFileHandle147 static handle_type GetInvalidHandle() {
148 return NULL;
149 }
150
Destruct__anon41724efc0111::MappedViewOfFileHandle151 static void Destruct(handle_type Handle) {
152 ::UnmapViewOfFile(Handle);
153 }
154
isValid__anon41724efc0111::MappedViewOfFileHandle155 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
windows_error(DWORD E)173 static std::error_code windows_error(DWORD E) { return mapWindowsError(E); }
174
GetFileNameFromHandle(HANDLE FileHandle,std::string & Name)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.
FindProgram(const std::string & Program,std::error_code & ec)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
ExceptionCodeToString(DWORD ExceptionCode)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
main(int argc,char ** argv)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