1//===- KillTheDoctor - Prevent Dr. Watson from stopping tests ---*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This program provides an extremely hacky way to stop Dr. Watson from starting
11// due to unhandled exceptions in child processes.
12//
13// This simply starts the program named in the first positional argument with
14// the arguments following it under a debugger. All this debugger does is catch
15// any unhandled exceptions thrown in the child process and close the program
16// (and hopefully tells someone about it).
17//
18// This also provides another really hacky method to prevent assert dialog boxes
19// from popping up. When --no-user32 is passed, if any process loads user32.dll,
20// we assume it is trying to call MessageBoxEx and terminate it. The proper way
21// to do this would be to actually set a break point, but there's quite a bit
22// of code involved to get the address of MessageBoxEx in the remote process's
23// address space due to Address space layout randomization (ASLR). This can be
24// added if it's ever actually needed.
25//
26// If the subprocess exits for any reason other than successful termination, -1
27// is returned. If the process exits normally the value it returned is returned.
28//
29// I hate Windows.
30//
31//===----------------------------------------------------------------------===//
32
33#include "llvm/ADT/STLExtras.h"
34#include "llvm/ADT/SmallString.h"
35#include "llvm/ADT/SmallVector.h"
36#include "llvm/ADT/StringExtras.h"
37#include "llvm/ADT/StringRef.h"
38#include "llvm/ADT/Twine.h"
39#include "llvm/Support/CommandLine.h"
40#include "llvm/Support/ManagedStatic.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
59using namespace llvm;
60
61#undef max
62
63namespace {
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
173static std::error_code windows_error(DWORD E) { return mapWindowsError(E); }
174
175static 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(),
208                                MappedFile,
209                                Filename,
210                                array_lengthof(Filename) - 1);
211
212  if (!Success)
213    return windows_error(::GetLastError());
214  else {
215    Name = Filename;
216    return std::error_code();
217  }
218}
219
220/// @brief Find program using shell lookup rules.
221/// @param Program This is either an absolute path, relative path, or simple a
222///        program name. Look in PATH for any programs that match. If no
223///        extension is present, try all extensions in PATHEXT.
224/// @return If ec == errc::success, The absolute path to the program. Otherwise
225///         the return value is undefined.
226static std::string FindProgram(const std::string &Program,
227                               std::error_code &ec) {
228  char PathName[MAX_PATH + 1];
229  typedef SmallVector<StringRef, 12> pathext_t;
230  pathext_t pathext;
231  // Check for the program without an extension (in case it already has one).
232  pathext.push_back("");
233  SplitString(std::getenv("PATHEXT"), pathext, ";");
234
235  for (pathext_t::iterator i = pathext.begin(), e = pathext.end(); i != e; ++i){
236    SmallString<5> ext;
237    for (std::size_t ii = 0, e = i->size(); ii != e; ++ii)
238      ext.push_back(::tolower((*i)[ii]));
239    LPCSTR Extension = NULL;
240    if (ext.size() && ext[0] == '.')
241      Extension = ext.c_str();
242    DWORD length = ::SearchPathA(NULL,
243                                 Program.c_str(),
244                                 Extension,
245                                 array_lengthof(PathName),
246                                 PathName,
247                                 NULL);
248    if (length == 0)
249      ec = windows_error(::GetLastError());
250    else if (length > array_lengthof(PathName)) {
251      // This may have been the file, return with error.
252      ec = windows_error(ERROR_BUFFER_OVERFLOW);
253      break;
254    } else {
255      // We found the path! Return it.
256      ec = std::error_code();
257      break;
258    }
259  }
260
261  // Make sure PathName is valid.
262  PathName[MAX_PATH] = 0;
263  return PathName;
264}
265
266static StringRef ExceptionCodeToString(DWORD ExceptionCode) {
267  switch(ExceptionCode) {
268  case EXCEPTION_ACCESS_VIOLATION: return "EXCEPTION_ACCESS_VIOLATION";
269  case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
270    return "EXCEPTION_ARRAY_BOUNDS_EXCEEDED";
271  case EXCEPTION_BREAKPOINT: return "EXCEPTION_BREAKPOINT";
272  case EXCEPTION_DATATYPE_MISALIGNMENT:
273    return "EXCEPTION_DATATYPE_MISALIGNMENT";
274  case EXCEPTION_FLT_DENORMAL_OPERAND: return "EXCEPTION_FLT_DENORMAL_OPERAND";
275  case EXCEPTION_FLT_DIVIDE_BY_ZERO: return "EXCEPTION_FLT_DIVIDE_BY_ZERO";
276  case EXCEPTION_FLT_INEXACT_RESULT: return "EXCEPTION_FLT_INEXACT_RESULT";
277  case EXCEPTION_FLT_INVALID_OPERATION:
278    return "EXCEPTION_FLT_INVALID_OPERATION";
279  case EXCEPTION_FLT_OVERFLOW: return "EXCEPTION_FLT_OVERFLOW";
280  case EXCEPTION_FLT_STACK_CHECK: return "EXCEPTION_FLT_STACK_CHECK";
281  case EXCEPTION_FLT_UNDERFLOW: return "EXCEPTION_FLT_UNDERFLOW";
282  case EXCEPTION_ILLEGAL_INSTRUCTION: return "EXCEPTION_ILLEGAL_INSTRUCTION";
283  case EXCEPTION_IN_PAGE_ERROR: return "EXCEPTION_IN_PAGE_ERROR";
284  case EXCEPTION_INT_DIVIDE_BY_ZERO: return "EXCEPTION_INT_DIVIDE_BY_ZERO";
285  case EXCEPTION_INT_OVERFLOW: return "EXCEPTION_INT_OVERFLOW";
286  case EXCEPTION_INVALID_DISPOSITION: return "EXCEPTION_INVALID_DISPOSITION";
287  case EXCEPTION_NONCONTINUABLE_EXCEPTION:
288    return "EXCEPTION_NONCONTINUABLE_EXCEPTION";
289  case EXCEPTION_PRIV_INSTRUCTION: return "EXCEPTION_PRIV_INSTRUCTION";
290  case EXCEPTION_SINGLE_STEP: return "EXCEPTION_SINGLE_STEP";
291  case EXCEPTION_STACK_OVERFLOW: return "EXCEPTION_STACK_OVERFLOW";
292  default: return "<unknown>";
293  }
294}
295
296int main(int argc, char **argv) {
297  // Print a stack trace if we signal out.
298  sys::PrintStackTraceOnErrorSignal();
299  PrettyStackTraceProgram X(argc, argv);
300  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
301
302  ToolName = argv[0];
303
304  cl::ParseCommandLineOptions(argc, argv, "Dr. Watson Assassin.\n");
305  if (ProgramToRun.size() == 0) {
306    cl::PrintHelpMessage();
307    return -1;
308  }
309
310  if (Timeout > std::numeric_limits<uint32_t>::max() / 1000) {
311    errs() << ToolName << ": Timeout value too large, must be less than: "
312                       << std::numeric_limits<uint32_t>::max() / 1000
313                       << '\n';
314    return -1;
315  }
316
317  std::string CommandLine(ProgramToRun);
318
319  std::error_code ec;
320  ProgramToRun = FindProgram(ProgramToRun, ec);
321  if (ec) {
322    errs() << ToolName << ": Failed to find program: '" << CommandLine
323           << "': " << ec.message() << '\n';
324    return -1;
325  }
326
327  if (TraceExecution)
328    errs() << ToolName << ": Found Program: " << ProgramToRun << '\n';
329
330  for (std::vector<std::string>::iterator i = Argv.begin(),
331                                          e = Argv.end();
332                                          i != e; ++i) {
333    CommandLine.push_back(' ');
334    CommandLine.append(*i);
335  }
336
337  if (TraceExecution)
338    errs() << ToolName << ": Program Image Path: " << ProgramToRun << '\n'
339           << ToolName << ": Command Line: " << CommandLine << '\n';
340
341  STARTUPINFO StartupInfo;
342  PROCESS_INFORMATION ProcessInfo;
343  std::memset(&StartupInfo, 0, sizeof(StartupInfo));
344  StartupInfo.cb = sizeof(StartupInfo);
345  std::memset(&ProcessInfo, 0, sizeof(ProcessInfo));
346
347  // Set error mode to not display any message boxes. The child process inherits
348  // this.
349  ::SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOGPFAULTERRORBOX);
350  ::_set_error_mode(_OUT_TO_STDERR);
351
352  BOOL success = ::CreateProcessA(ProgramToRun.c_str(),
353                            LPSTR(CommandLine.c_str()),
354                                  NULL,
355                                  NULL,
356                                  FALSE,
357                                  DEBUG_PROCESS,
358                                  NULL,
359                                  NULL,
360                                  &StartupInfo,
361                                  &ProcessInfo);
362  if (!success) {
363    errs() << ToolName << ": Failed to run program: '" << ProgramToRun << "': "
364           << std::error_code(windows_error(::GetLastError())).message()
365           << '\n';
366    return -1;
367  }
368
369  // Make sure ::CloseHandle is called on exit.
370  std::map<DWORD, HANDLE> ProcessIDToHandle;
371
372  DEBUG_EVENT DebugEvent;
373  std::memset(&DebugEvent, 0, sizeof(DebugEvent));
374  DWORD dwContinueStatus = DBG_CONTINUE;
375
376  // Run the program under the debugger until either it exits, or throws an
377  // exception.
378  if (TraceExecution)
379    errs() << ToolName << ": Debugging...\n";
380
381  while(true) {
382    DWORD TimeLeft = INFINITE;
383    if (Timeout > 0) {
384      FILETIME CreationTime, ExitTime, KernelTime, UserTime;
385      ULARGE_INTEGER a, b;
386      success = ::GetProcessTimes(ProcessInfo.hProcess,
387                                  &CreationTime,
388                                  &ExitTime,
389                                  &KernelTime,
390                                  &UserTime);
391      if (!success) {
392        ec = windows_error(::GetLastError());
393
394        errs() << ToolName << ": Failed to get process times: "
395               << ec.message() << '\n';
396        return -1;
397      }
398      a.LowPart = KernelTime.dwLowDateTime;
399      a.HighPart = KernelTime.dwHighDateTime;
400      b.LowPart = UserTime.dwLowDateTime;
401      b.HighPart = UserTime.dwHighDateTime;
402      // Convert 100-nanosecond units to milliseconds.
403      uint64_t TotalTimeMiliseconds = (a.QuadPart + b.QuadPart) / 10000;
404      // Handle the case where the process has been running for more than 49
405      // days.
406      if (TotalTimeMiliseconds > std::numeric_limits<uint32_t>::max()) {
407        errs() << ToolName << ": Timeout Failed: Process has been running for"
408                              "more than 49 days.\n";
409        return -1;
410      }
411
412      // We check with > instead of using Timeleft because if
413      // TotalTimeMiliseconds is greater than Timeout * 1000, TimeLeft would
414      // underflow.
415      if (TotalTimeMiliseconds > (Timeout * 1000)) {
416        errs() << ToolName << ": Process timed out.\n";
417        ::TerminateProcess(ProcessInfo.hProcess, -1);
418        // Otherwise other stuff starts failing...
419        return -1;
420      }
421
422      TimeLeft = (Timeout * 1000) - static_cast<uint32_t>(TotalTimeMiliseconds);
423    }
424    success = WaitForDebugEvent(&DebugEvent, TimeLeft);
425
426    if (!success) {
427      DWORD LastError = ::GetLastError();
428      ec = windows_error(LastError);
429
430      if (LastError == ERROR_SEM_TIMEOUT || LastError == WSAETIMEDOUT) {
431        errs() << ToolName << ": Process timed out.\n";
432        ::TerminateProcess(ProcessInfo.hProcess, -1);
433        // Otherwise other stuff starts failing...
434        return -1;
435      }
436
437      errs() << ToolName << ": Failed to wait for debug event in program: '"
438             << ProgramToRun << "': " << ec.message() << '\n';
439      return -1;
440    }
441
442    switch(DebugEvent.dwDebugEventCode) {
443    case CREATE_PROCESS_DEBUG_EVENT:
444      // Make sure we remove the handle on exit.
445      if (TraceExecution)
446        errs() << ToolName << ": Debug Event: CREATE_PROCESS_DEBUG_EVENT\n";
447      ProcessIDToHandle[DebugEvent.dwProcessId] =
448        DebugEvent.u.CreateProcessInfo.hProcess;
449      ::CloseHandle(DebugEvent.u.CreateProcessInfo.hFile);
450      break;
451    case EXIT_PROCESS_DEBUG_EVENT: {
452        if (TraceExecution)
453          errs() << ToolName << ": Debug Event: EXIT_PROCESS_DEBUG_EVENT\n";
454
455        // If this is the process we originally created, exit with its exit
456        // code.
457        if (DebugEvent.dwProcessId == ProcessInfo.dwProcessId)
458          return DebugEvent.u.ExitProcess.dwExitCode;
459
460        // Otherwise cleanup any resources we have for it.
461        std::map<DWORD, HANDLE>::iterator ExitingProcess =
462          ProcessIDToHandle.find(DebugEvent.dwProcessId);
463        if (ExitingProcess == ProcessIDToHandle.end()) {
464          errs() << ToolName << ": Got unknown process id!\n";
465          return -1;
466        }
467        ::CloseHandle(ExitingProcess->second);
468        ProcessIDToHandle.erase(ExitingProcess);
469      }
470      break;
471    case CREATE_THREAD_DEBUG_EVENT:
472      ::CloseHandle(DebugEvent.u.CreateThread.hThread);
473      break;
474    case LOAD_DLL_DEBUG_EVENT: {
475        // Cleanup the file handle.
476        FileScopedHandle DLLFile(DebugEvent.u.LoadDll.hFile);
477        std::string DLLName;
478        ec = GetFileNameFromHandle(DLLFile, DLLName);
479        if (ec) {
480          DLLName = "<failed to get file name from file handle> : ";
481          DLLName += ec.message();
482        }
483        if (TraceExecution) {
484          errs() << ToolName << ": Debug Event: LOAD_DLL_DEBUG_EVENT\n";
485          errs().indent(ToolName.size()) << ": DLL Name : " << DLLName << '\n';
486        }
487
488        if (NoUser32 && sys::path::stem(DLLName) == "user32") {
489          // Program is loading user32.dll, in the applications we are testing,
490          // this only happens if an assert has fired. By now the message has
491          // already been printed, so simply close the program.
492          errs() << ToolName << ": user32.dll loaded!\n";
493          errs().indent(ToolName.size())
494                 << ": This probably means that assert was called. Closing "
495                    "program to prevent message box from popping up.\n";
496          dwContinueStatus = DBG_CONTINUE;
497          ::TerminateProcess(ProcessIDToHandle[DebugEvent.dwProcessId], -1);
498          return -1;
499        }
500      }
501      break;
502    case EXCEPTION_DEBUG_EVENT: {
503        // Close the application if this exception will not be handled by the
504        // child application.
505        if (TraceExecution)
506          errs() << ToolName << ": Debug Event: EXCEPTION_DEBUG_EVENT\n";
507
508        EXCEPTION_DEBUG_INFO  &Exception = DebugEvent.u.Exception;
509        if (Exception.dwFirstChance > 0) {
510          if (TraceExecution) {
511            errs().indent(ToolName.size()) << ": Debug Info : ";
512            errs() << "First chance exception at "
513                   << Exception.ExceptionRecord.ExceptionAddress
514                   << ", exception code: "
515                   << ExceptionCodeToString(
516                        Exception.ExceptionRecord.ExceptionCode)
517                   << " (" << Exception.ExceptionRecord.ExceptionCode << ")\n";
518          }
519          dwContinueStatus = DBG_EXCEPTION_NOT_HANDLED;
520        } else {
521          errs() << ToolName << ": Unhandled exception in: " << ProgramToRun
522                 << "!\n";
523                 errs().indent(ToolName.size()) << ": location: ";
524                 errs() << Exception.ExceptionRecord.ExceptionAddress
525                        << ", exception code: "
526                        << ExceptionCodeToString(
527                            Exception.ExceptionRecord.ExceptionCode)
528                        << " (" << Exception.ExceptionRecord.ExceptionCode
529                        << ")\n";
530          dwContinueStatus = DBG_CONTINUE;
531          ::TerminateProcess(ProcessIDToHandle[DebugEvent.dwProcessId], -1);
532          return -1;
533        }
534      }
535      break;
536    default:
537      // Do nothing.
538      if (TraceExecution)
539        errs() << ToolName << ": Debug Event: <unknown>\n";
540      break;
541    }
542
543    success = ContinueDebugEvent(DebugEvent.dwProcessId,
544                                 DebugEvent.dwThreadId,
545                                 dwContinueStatus);
546    if (!success) {
547      ec = windows_error(::GetLastError());
548      errs() << ToolName << ": Failed to continue debugging program: '"
549             << ProgramToRun << "': " << ec.message() << '\n';
550      return -1;
551    }
552
553    dwContinueStatus = DBG_CONTINUE;
554  }
555
556  assert(0 && "Fell out of debug loop. This shouldn't be possible!");
557  return -1;
558}
559