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/raw_ostream.h"
43#include "llvm/Support/type_traits.h"
44#include "llvm/Support/Signals.h"
45#include "llvm/Support/system_error.h"
46#include <algorithm>
47#include <cerrno>
48#include <cstdlib>
49#include <map>
50#include <string>
51#include <Windows.h>
52#include <WinError.h>
53#include <Dbghelp.h>
54#include <psapi.h>
55using namespace llvm;
56
57#undef max
58
59namespace {
60  cl::opt<std::string> ProgramToRun(cl::Positional,
61    cl::desc("<program to run>"));
62  cl::list<std::string>  Argv(cl::ConsumeAfter,
63    cl::desc("<program arguments>..."));
64  cl::opt<bool> TraceExecution("x",
65    cl::desc("Print detailed output about what is being run to stderr."));
66  cl::opt<unsigned> Timeout("t", cl::init(0),
67    cl::desc("Set maximum runtime in seconds. Defaults to infinite."));
68  cl::opt<bool> NoUser32("no-user32",
69    cl::desc("Terminate process if it loads user32.dll."));
70
71  StringRef ToolName;
72
73  template <typename HandleType>
74  class ScopedHandle {
75    typedef typename HandleType::handle_type handle_type;
76
77    handle_type Handle;
78
79  public:
80    ScopedHandle()
81      : Handle(HandleType::GetInvalidHandle()) {}
82
83    explicit ScopedHandle(handle_type handle)
84      : Handle(handle) {}
85
86    ~ScopedHandle() {
87      HandleType::Destruct(Handle);
88    }
89
90    ScopedHandle& operator=(handle_type handle) {
91      // Cleanup current handle.
92      if (!HandleType::isValid(Handle))
93        HandleType::Destruct(Handle);
94      Handle = handle;
95      return *this;
96    }
97
98    operator bool() const {
99      return HandleType::isValid(Handle);
100    }
101
102    operator handle_type() {
103      return Handle;
104    }
105  };
106
107  // This implements the most common handle in the Windows API.
108  struct CommonHandle {
109    typedef HANDLE handle_type;
110
111    static handle_type GetInvalidHandle() {
112      return INVALID_HANDLE_VALUE;
113    }
114
115    static void Destruct(handle_type Handle) {
116      ::CloseHandle(Handle);
117    }
118
119    static bool isValid(handle_type Handle) {
120      return Handle != GetInvalidHandle();
121    }
122  };
123
124  struct FileMappingHandle {
125    typedef HANDLE handle_type;
126
127    static handle_type GetInvalidHandle() {
128      return NULL;
129    }
130
131    static void Destruct(handle_type Handle) {
132      ::CloseHandle(Handle);
133    }
134
135    static bool isValid(handle_type Handle) {
136      return Handle != GetInvalidHandle();
137    }
138  };
139
140  struct MappedViewOfFileHandle {
141    typedef LPVOID handle_type;
142
143    static handle_type GetInvalidHandle() {
144      return NULL;
145    }
146
147    static void Destruct(handle_type Handle) {
148      ::UnmapViewOfFile(Handle);
149    }
150
151    static bool isValid(handle_type Handle) {
152      return Handle != GetInvalidHandle();
153    }
154  };
155
156  struct ProcessHandle : CommonHandle {};
157  struct ThreadHandle  : CommonHandle {};
158  struct TokenHandle   : CommonHandle {};
159  struct FileHandle    : CommonHandle {};
160
161  typedef ScopedHandle<FileMappingHandle>       FileMappingScopedHandle;
162  typedef ScopedHandle<MappedViewOfFileHandle>  MappedViewOfFileScopedHandle;
163  typedef ScopedHandle<ProcessHandle>           ProcessScopedHandle;
164  typedef ScopedHandle<ThreadHandle>            ThreadScopedHandle;
165  typedef ScopedHandle<TokenHandle>             TokenScopedHandle;
166  typedef ScopedHandle<FileHandle>              FileScopedHandle;
167}
168
169static error_code GetFileNameFromHandle(HANDLE FileHandle,
170                                        std::string& Name) {
171  char Filename[MAX_PATH+1];
172  bool Success = false;
173  Name.clear();
174
175  // Get the file size.
176  LARGE_INTEGER FileSize;
177  Success = ::GetFileSizeEx(FileHandle, &FileSize);
178
179  if (!Success)
180    return windows_error(::GetLastError());
181
182  // Create a file mapping object.
183  FileMappingScopedHandle FileMapping(
184    ::CreateFileMappingA(FileHandle,
185                         NULL,
186                         PAGE_READONLY,
187                         0,
188                         1,
189                         NULL));
190
191  if (!FileMapping)
192    return windows_error(::GetLastError());
193
194  // Create a file mapping to get the file name.
195  MappedViewOfFileScopedHandle MappedFile(
196    ::MapViewOfFile(FileMapping, FILE_MAP_READ, 0, 0, 1));
197
198  if (!MappedFile)
199    return windows_error(::GetLastError());
200
201  Success = ::GetMappedFileNameA(::GetCurrentProcess(),
202                                MappedFile,
203                                Filename,
204                                array_lengthof(Filename) - 1);
205
206  if (!Success)
207    return windows_error(::GetLastError());
208  else {
209    Name = Filename;
210    return windows_error::success;
211  }
212}
213
214/// @brief Find program using shell lookup rules.
215/// @param Program This is either an absolute path, relative path, or simple a
216///        program name. Look in PATH for any programs that match. If no
217///        extension is present, try all extensions in PATHEXT.
218/// @return If ec == errc::success, The absolute path to the program. Otherwise
219///         the return value is undefined.
220static std::string FindProgram(const std::string &Program, error_code &ec) {
221  char PathName[MAX_PATH + 1];
222  typedef SmallVector<StringRef, 12> pathext_t;
223  pathext_t pathext;
224  // Check for the program without an extension (in case it already has one).
225  pathext.push_back("");
226  SplitString(std::getenv("PATHEXT"), pathext, ";");
227
228  for (pathext_t::iterator i = pathext.begin(), e = pathext.end(); i != e; ++i){
229    SmallString<5> ext;
230    for (std::size_t ii = 0, e = i->size(); ii != e; ++ii)
231      ext.push_back(::tolower((*i)[ii]));
232    LPCSTR Extension = NULL;
233    if (ext.size() && ext[0] == '.')
234      Extension = ext.c_str();
235    DWORD length = ::SearchPathA(NULL,
236                                 Program.c_str(),
237                                 Extension,
238                                 array_lengthof(PathName),
239                                 PathName,
240                                 NULL);
241    if (length == 0)
242      ec = windows_error(::GetLastError());
243    else if (length > array_lengthof(PathName)) {
244      // This may have been the file, return with error.
245      ec = windows_error::buffer_overflow;
246      break;
247    } else {
248      // We found the path! Return it.
249      ec = windows_error::success;
250      break;
251    }
252  }
253
254  // Make sure PathName is valid.
255  PathName[MAX_PATH] = 0;
256  return PathName;
257}
258
259static StringRef ExceptionCodeToString(DWORD ExceptionCode) {
260  switch(ExceptionCode) {
261  case EXCEPTION_ACCESS_VIOLATION: return "EXCEPTION_ACCESS_VIOLATION";
262  case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
263    return "EXCEPTION_ARRAY_BOUNDS_EXCEEDED";
264  case EXCEPTION_BREAKPOINT: return "EXCEPTION_BREAKPOINT";
265  case EXCEPTION_DATATYPE_MISALIGNMENT:
266    return "EXCEPTION_DATATYPE_MISALIGNMENT";
267  case EXCEPTION_FLT_DENORMAL_OPERAND: return "EXCEPTION_FLT_DENORMAL_OPERAND";
268  case EXCEPTION_FLT_DIVIDE_BY_ZERO: return "EXCEPTION_FLT_DIVIDE_BY_ZERO";
269  case EXCEPTION_FLT_INEXACT_RESULT: return "EXCEPTION_FLT_INEXACT_RESULT";
270  case EXCEPTION_FLT_INVALID_OPERATION:
271    return "EXCEPTION_FLT_INVALID_OPERATION";
272  case EXCEPTION_FLT_OVERFLOW: return "EXCEPTION_FLT_OVERFLOW";
273  case EXCEPTION_FLT_STACK_CHECK: return "EXCEPTION_FLT_STACK_CHECK";
274  case EXCEPTION_FLT_UNDERFLOW: return "EXCEPTION_FLT_UNDERFLOW";
275  case EXCEPTION_ILLEGAL_INSTRUCTION: return "EXCEPTION_ILLEGAL_INSTRUCTION";
276  case EXCEPTION_IN_PAGE_ERROR: return "EXCEPTION_IN_PAGE_ERROR";
277  case EXCEPTION_INT_DIVIDE_BY_ZERO: return "EXCEPTION_INT_DIVIDE_BY_ZERO";
278  case EXCEPTION_INT_OVERFLOW: return "EXCEPTION_INT_OVERFLOW";
279  case EXCEPTION_INVALID_DISPOSITION: return "EXCEPTION_INVALID_DISPOSITION";
280  case EXCEPTION_NONCONTINUABLE_EXCEPTION:
281    return "EXCEPTION_NONCONTINUABLE_EXCEPTION";
282  case EXCEPTION_PRIV_INSTRUCTION: return "EXCEPTION_PRIV_INSTRUCTION";
283  case EXCEPTION_SINGLE_STEP: return "EXCEPTION_SINGLE_STEP";
284  case EXCEPTION_STACK_OVERFLOW: return "EXCEPTION_STACK_OVERFLOW";
285  default: return "<unknown>";
286  }
287}
288
289int main(int argc, char **argv) {
290  // Print a stack trace if we signal out.
291  sys::PrintStackTraceOnErrorSignal();
292  PrettyStackTraceProgram X(argc, argv);
293  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
294
295  ToolName = argv[0];
296
297  cl::ParseCommandLineOptions(argc, argv, "Dr. Watson Assassin.\n");
298  if (ProgramToRun.size() == 0) {
299    cl::PrintHelpMessage();
300    return -1;
301  }
302
303  if (Timeout > std::numeric_limits<uint32_t>::max() / 1000) {
304    errs() << ToolName << ": Timeout value too large, must be less than: "
305                       << std::numeric_limits<uint32_t>::max() / 1000
306                       << '\n';
307    return -1;
308  }
309
310  std::string CommandLine(ProgramToRun);
311
312  error_code ec;
313  ProgramToRun = FindProgram(ProgramToRun, ec);
314  if (ec) {
315    errs() << ToolName << ": Failed to find program: '" << CommandLine
316           << "': " << ec.message() << '\n';
317    return -1;
318  }
319
320  if (TraceExecution)
321    errs() << ToolName << ": Found Program: " << ProgramToRun << '\n';
322
323  for (std::vector<std::string>::iterator i = Argv.begin(),
324                                          e = Argv.end();
325                                          i != e; ++i) {
326    CommandLine.push_back(' ');
327    CommandLine.append(*i);
328  }
329
330  if (TraceExecution)
331    errs() << ToolName << ": Program Image Path: " << ProgramToRun << '\n'
332           << ToolName << ": Command Line: " << CommandLine << '\n';
333
334  STARTUPINFO StartupInfo;
335  PROCESS_INFORMATION ProcessInfo;
336  std::memset(&StartupInfo, 0, sizeof(StartupInfo));
337  StartupInfo.cb = sizeof(StartupInfo);
338  std::memset(&ProcessInfo, 0, sizeof(ProcessInfo));
339
340  // Set error mode to not display any message boxes. The child process inherits
341  // this.
342  ::SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOGPFAULTERRORBOX);
343  ::_set_error_mode(_OUT_TO_STDERR);
344
345  BOOL success = ::CreateProcessA(ProgramToRun.c_str(),
346                            LPSTR(CommandLine.c_str()),
347                                  NULL,
348                                  NULL,
349                                  FALSE,
350                                  DEBUG_PROCESS,
351                                  NULL,
352                                  NULL,
353                                  &StartupInfo,
354                                  &ProcessInfo);
355  if (!success) {
356    errs() << ToolName << ": Failed to run program: '" << ProgramToRun
357           << "': " << error_code(windows_error(::GetLastError())).message()
358           << '\n';
359    return -1;
360  }
361
362  // Make sure ::CloseHandle is called on exit.
363  std::map<DWORD, HANDLE> ProcessIDToHandle;
364
365  DEBUG_EVENT DebugEvent;
366  std::memset(&DebugEvent, 0, sizeof(DebugEvent));
367  DWORD dwContinueStatus = DBG_CONTINUE;
368
369  // Run the program under the debugger until either it exits, or throws an
370  // exception.
371  if (TraceExecution)
372    errs() << ToolName << ": Debugging...\n";
373
374  while(true) {
375    DWORD TimeLeft = INFINITE;
376    if (Timeout > 0) {
377      FILETIME CreationTime, ExitTime, KernelTime, UserTime;
378      ULARGE_INTEGER a, b;
379      success = ::GetProcessTimes(ProcessInfo.hProcess,
380                                  &CreationTime,
381                                  &ExitTime,
382                                  &KernelTime,
383                                  &UserTime);
384      if (!success) {
385        ec = windows_error(::GetLastError());
386
387        errs() << ToolName << ": Failed to get process times: "
388               << ec.message() << '\n';
389        return -1;
390      }
391      a.LowPart = KernelTime.dwLowDateTime;
392      a.HighPart = KernelTime.dwHighDateTime;
393      b.LowPart = UserTime.dwLowDateTime;
394      b.HighPart = UserTime.dwHighDateTime;
395      // Convert 100-nanosecond units to milliseconds.
396      uint64_t TotalTimeMiliseconds = (a.QuadPart + b.QuadPart) / 10000;
397      // Handle the case where the process has been running for more than 49
398      // days.
399      if (TotalTimeMiliseconds > std::numeric_limits<uint32_t>::max()) {
400        errs() << ToolName << ": Timeout Failed: Process has been running for"
401                              "more than 49 days.\n";
402        return -1;
403      }
404
405      // We check with > instead of using Timeleft because if
406      // TotalTimeMiliseconds is greater than Timeout * 1000, TimeLeft would
407      // underflow.
408      if (TotalTimeMiliseconds > (Timeout * 1000)) {
409        errs() << ToolName << ": Process timed out.\n";
410        ::TerminateProcess(ProcessInfo.hProcess, -1);
411        // Otherwise other stuff starts failing...
412        return -1;
413      }
414
415      TimeLeft = (Timeout * 1000) - static_cast<uint32_t>(TotalTimeMiliseconds);
416    }
417    success = WaitForDebugEvent(&DebugEvent, TimeLeft);
418
419    if (!success) {
420      ec = windows_error(::GetLastError());
421
422      if (ec == errc::timed_out) {
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