//===- KillTheDoctor - Prevent Dr. Watson from stopping tests ---*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This program provides an extremely hacky way to stop Dr. Watson from starting
// due to unhandled exceptions in child processes.
//
// This simply starts the program named in the first positional argument with
// the arguments following it under a debugger. All this debugger does is catch
// any unhandled exceptions thrown in the child process and close the program
// (and hopefully tells someone about it).
//
// This also provides another really hacky method to prevent assert dialog boxes
// from popping up. When --no-user32 is passed, if any process loads user32.dll,
// we assume it is trying to call MessageBoxEx and terminate it. The proper way
// to do this would be to actually set a break point, but there's quite a bit
// of code involved to get the address of MessageBoxEx in the remote process's
// address space due to Address space layout randomization (ASLR). This can be
// added if it's ever actually needed.
//
// If the subprocess exits for any reason other than successful termination, -1
// is returned. If the process exits normally the value it returned is returned.
//
// I hate Windows.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/PrettyStackTrace.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/WindowsError.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/type_traits.h"
#include <algorithm>
#include <cerrno>
#include <cstdlib>
#include <map>
#include <string>
#include <system_error>
// These includes must be last.
#include <windows.h>
#include <winerror.h>
#include <dbghelp.h>
#include <psapi.h>
using namespace llvm;
#undef max
namespace {
cl::opt<std::string> ProgramToRun(cl::Positional,
cl::desc("<program to run>"));
cl::list<std::string> Argv(cl::ConsumeAfter,
cl::desc("<program arguments>..."));
cl::opt<bool> TraceExecution("x",
cl::desc("Print detailed output about what is being run to stderr."));
cl::opt<unsigned> Timeout("t", cl::init(0),
cl::desc("Set maximum runtime in seconds. Defaults to infinite."));
cl::opt<bool> NoUser32("no-user32",
cl::desc("Terminate process if it loads user32.dll."));
StringRef ToolName;
template <typename HandleType>
class ScopedHandle {
typedef typename HandleType::handle_type handle_type;
handle_type Handle;
public:
ScopedHandle()
: Handle(HandleType::GetInvalidHandle()) {}
explicit ScopedHandle(handle_type handle)
: Handle(handle) {}
~ScopedHandle() {
HandleType::Destruct(Handle);
}
ScopedHandle& operator=(handle_type handle) {
// Cleanup current handle.
if (!HandleType::isValid(Handle))
HandleType::Destruct(Handle);
Handle = handle;
return *this;
}
operator bool() const {
return HandleType::isValid(Handle);
}
operator handle_type() {
return Handle;
}
};
// This implements the most common handle in the Windows API.
struct CommonHandle {
typedef HANDLE handle_type;
static handle_type GetInvalidHandle() {
return INVALID_HANDLE_VALUE;
}
static void Destruct(handle_type Handle) {
::CloseHandle(Handle);
}
static bool isValid(handle_type Handle) {
return Handle != GetInvalidHandle();
}
};
struct FileMappingHandle {
typedef HANDLE handle_type;
static handle_type GetInvalidHandle() {
return NULL;
}
static void Destruct(handle_type Handle) {
::CloseHandle(Handle);
}
static bool isValid(handle_type Handle) {
return Handle != GetInvalidHandle();
}
};
struct MappedViewOfFileHandle {
typedef LPVOID handle_type;
static handle_type GetInvalidHandle() {
return NULL;
}
static void Destruct(handle_type Handle) {
::UnmapViewOfFile(Handle);
}
static bool isValid(handle_type Handle) {
return Handle != GetInvalidHandle();
}
};
struct ProcessHandle : CommonHandle {};
struct ThreadHandle : CommonHandle {};
struct TokenHandle : CommonHandle {};
struct FileHandle : CommonHandle {};
typedef ScopedHandle<FileMappingHandle> FileMappingScopedHandle;
typedef ScopedHandle<MappedViewOfFileHandle> MappedViewOfFileScopedHandle;
typedef ScopedHandle<ProcessHandle> ProcessScopedHandle;
typedef ScopedHandle<ThreadHandle> ThreadScopedHandle;
typedef ScopedHandle<TokenHandle> TokenScopedHandle;
typedef ScopedHandle<FileHandle> FileScopedHandle;
}
static std::error_code windows_error(DWORD E) { return mapWindowsError(E); }
static std::error_code GetFileNameFromHandle(HANDLE FileHandle,
std::string &Name) {
char Filename[MAX_PATH+1];
bool Success = false;
Name.clear();
// Get the file size.
LARGE_INTEGER FileSize;
Success = ::GetFileSizeEx(FileHandle, &FileSize);
if (!Success)
return windows_error(::GetLastError());
// Create a file mapping object.
FileMappingScopedHandle FileMapping(
::CreateFileMappingA(FileHandle,
NULL,
PAGE_READONLY,
0,
1,
NULL));
if (!FileMapping)
return windows_error(::GetLastError());
// Create a file mapping to get the file name.
MappedViewOfFileScopedHandle MappedFile(
::MapViewOfFile(FileMapping, FILE_MAP_READ, 0, 0, 1));
if (!MappedFile)
return windows_error(::GetLastError());
Success = ::GetMappedFileNameA(::GetCurrentProcess(), MappedFile, Filename,
std::size(Filename) - 1);
if (!Success)
return windows_error(::GetLastError());
else {
Name = Filename;
return std::error_code();
}
}
/// Find program using shell lookup rules.
/// @param Program This is either an absolute path, relative path, or simple a
/// program name. Look in PATH for any programs that match. If no
/// extension is present, try all extensions in PATHEXT.
/// @return If ec == errc::success, The absolute path to the program. Otherwise
/// the return value is undefined.
static std::string FindProgram(const std::string &Program,
std::error_code &ec) {
char PathName[MAX_PATH + 1];
typedef SmallVector<StringRef, 12> pathext_t;
pathext_t pathext;
// Check for the program without an extension (in case it already has one).
pathext.push_back("");
SplitString(std::getenv("PATHEXT"), pathext, ";");
for (pathext_t::iterator i = pathext.begin(), e = pathext.end(); i != e; ++i){
SmallString<5> ext;
for (std::size_t ii = 0, e = i->size(); ii != e; ++ii)
ext.push_back(::tolower((*i)[ii]));
LPCSTR Extension = NULL;
if (ext.size() && ext[0] == '.')
Extension = ext.c_str();
DWORD length = ::SearchPathA(NULL, Program.c_str(), Extension,
std::size(PathName), PathName, NULL);
if (length == 0)
ec = windows_error(::GetLastError());
else if (length > std::size(PathName)) {
// This may have been the file, return with error.
ec = windows_error(ERROR_BUFFER_OVERFLOW);
break;
} else {
// We found the path! Return it.
ec = std::error_code();
break;
}
}
// Make sure PathName is valid.
PathName[MAX_PATH] = 0;
return PathName;
}
static StringRef ExceptionCodeToString(DWORD ExceptionCode) {
switch(ExceptionCode) {
case EXCEPTION_ACCESS_VIOLATION: return "EXCEPTION_ACCESS_VIOLATION";
case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
return "EXCEPTION_ARRAY_BOUNDS_EXCEEDED";
case EXCEPTION_BREAKPOINT: return "EXCEPTION_BREAKPOINT";
case EXCEPTION_DATATYPE_MISALIGNMENT:
return "EXCEPTION_DATATYPE_MISALIGNMENT";
case EXCEPTION_FLT_DENORMAL_OPERAND: return "EXCEPTION_FLT_DENORMAL_OPERAND";
case EXCEPTION_FLT_DIVIDE_BY_ZERO: return "EXCEPTION_FLT_DIVIDE_BY_ZERO";
case EXCEPTION_FLT_INEXACT_RESULT: return "EXCEPTION_FLT_INEXACT_RESULT";
case EXCEPTION_FLT_INVALID_OPERATION:
return "EXCEPTION_FLT_INVALID_OPERATION";
case EXCEPTION_FLT_OVERFLOW: return "EXCEPTION_FLT_OVERFLOW";
case EXCEPTION_FLT_STACK_CHECK: return "EXCEPTION_FLT_STACK_CHECK";
case EXCEPTION_FLT_UNDERFLOW: return "EXCEPTION_FLT_UNDERFLOW";
case EXCEPTION_ILLEGAL_INSTRUCTION: return "EXCEPTION_ILLEGAL_INSTRUCTION";
case EXCEPTION_IN_PAGE_ERROR: return "EXCEPTION_IN_PAGE_ERROR";
case EXCEPTION_INT_DIVIDE_BY_ZERO: return "EXCEPTION_INT_DIVIDE_BY_ZERO";
case EXCEPTION_INT_OVERFLOW: return "EXCEPTION_INT_OVERFLOW";
case EXCEPTION_INVALID_DISPOSITION: return "EXCEPTION_INVALID_DISPOSITION";
case EXCEPTION_NONCONTINUABLE_EXCEPTION:
return "EXCEPTION_NONCONTINUABLE_EXCEPTION";
case EXCEPTION_PRIV_INSTRUCTION: return "EXCEPTION_PRIV_INSTRUCTION";
case EXCEPTION_SINGLE_STEP: return "EXCEPTION_SINGLE_STEP";
case EXCEPTION_STACK_OVERFLOW: return "EXCEPTION_STACK_OVERFLOW";
default: return "<unknown>";
}
}
int main(int argc, char **argv) {
// Print a stack trace if we signal out.
sys::PrintStackTraceOnErrorSignal(argv[0]);
PrettyStackTraceProgram X(argc, argv);
llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
ToolName = argv[0];
cl::ParseCommandLineOptions(argc, argv, "Dr. Watson Assassin.\n");
if (ProgramToRun.size() == 0) {
cl::PrintHelpMessage();
return -1;
}
if (Timeout > std::numeric_limits<uint32_t>::max() / 1000) {
errs() << ToolName << ": Timeout value too large, must be less than: "
<< std::numeric_limits<uint32_t>::max() / 1000
<< '\n';
return -1;
}
std::string CommandLine(ProgramToRun);
std::error_code ec;
ProgramToRun = FindProgram(ProgramToRun, ec);
if (ec) {
errs() << ToolName << ": Failed to find program: '" << CommandLine
<< "': " << ec.message() << '\n';
return -1;
}
if (TraceExecution)
errs() << ToolName << ": Found Program: " << ProgramToRun << '\n';
for (const std::string &Arg : Argv) {
CommandLine.push_back(' ');
CommandLine.append(Arg);
}
if (TraceExecution)
errs() << ToolName << ": Program Image Path: " << ProgramToRun << '\n'
<< ToolName << ": Command Line: " << CommandLine << '\n';
STARTUPINFOA StartupInfo;
PROCESS_INFORMATION ProcessInfo;
std::memset(&StartupInfo, 0, sizeof(StartupInfo));
StartupInfo.cb = sizeof(StartupInfo);
std::memset(&ProcessInfo, 0, sizeof(ProcessInfo));
// Set error mode to not display any message boxes. The child process inherits
// this.
::SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOGPFAULTERRORBOX);
::_set_error_mode(_OUT_TO_STDERR);
BOOL success = ::CreateProcessA(ProgramToRun.c_str(),
const_cast<LPSTR>(CommandLine.c_str()),
NULL,
NULL,
FALSE,
DEBUG_PROCESS,
NULL,
NULL,
&StartupInfo,
&ProcessInfo);
if (!success) {
errs() << ToolName << ": Failed to run program: '" << ProgramToRun << "': "
<< std::error_code(windows_error(::GetLastError())).message()
<< '\n';
return -1;
}
// Make sure ::CloseHandle is called on exit.
std::map<DWORD, HANDLE> ProcessIDToHandle;
DEBUG_EVENT DebugEvent;
std::memset(&DebugEvent, 0, sizeof(DebugEvent));
DWORD dwContinueStatus = DBG_CONTINUE;
// Run the program under the debugger until either it exits, or throws an
// exception.
if (TraceExecution)
errs() << ToolName << ": Debugging...\n";
while(true) {
DWORD TimeLeft = INFINITE;
if (Timeout > 0) {
FILETIME CreationTime, ExitTime, KernelTime, UserTime;
ULARGE_INTEGER a, b;
success = ::GetProcessTimes(ProcessInfo.hProcess,
&CreationTime,
&ExitTime,
&KernelTime,
&UserTime);
if (!success) {
ec = windows_error(::GetLastError());
errs() << ToolName << ": Failed to get process times: "
<< ec.message() << '\n';
return -1;
}
a.LowPart = KernelTime.dwLowDateTime;
a.HighPart = KernelTime.dwHighDateTime;
b.LowPart = UserTime.dwLowDateTime;
b.HighPart = UserTime.dwHighDateTime;
// Convert 100-nanosecond units to milliseconds.
uint64_t TotalTimeMiliseconds = (a.QuadPart + b.QuadPart) / 10000;
// Handle the case where the process has been running for more than 49
// days.
if (TotalTimeMiliseconds > std::numeric_limits<uint32_t>::max()) {
errs() << ToolName << ": Timeout Failed: Process has been running for"
"more than 49 days.\n";
return -1;
}
// We check with > instead of using Timeleft because if
// TotalTimeMiliseconds is greater than Timeout * 1000, TimeLeft would
// underflow.
if (TotalTimeMiliseconds > (Timeout * 1000)) {
errs() << ToolName << ": Process timed out.\n";
::TerminateProcess(ProcessInfo.hProcess, -1);
// Otherwise other stuff starts failing...
return -1;
}
TimeLeft = (Timeout * 1000) - static_cast<uint32_t>(TotalTimeMiliseconds);
}
success = WaitForDebugEvent(&DebugEvent, TimeLeft);
if (!success) {
DWORD LastError = ::GetLastError();
ec = windows_error(LastError);
if (LastError == ERROR_SEM_TIMEOUT || LastError == WSAETIMEDOUT) {
errs() << ToolName << ": Process timed out.\n";
::TerminateProcess(ProcessInfo.hProcess, -1);
// Otherwise other stuff starts failing...
return -1;
}
errs() << ToolName << ": Failed to wait for debug event in program: '"
<< ProgramToRun << "': " << ec.message() << '\n';
return -1;
}
switch(DebugEvent.dwDebugEventCode) {
case CREATE_PROCESS_DEBUG_EVENT:
// Make sure we remove the handle on exit.
if (TraceExecution)
errs() << ToolName << ": Debug Event: CREATE_PROCESS_DEBUG_EVENT\n";
ProcessIDToHandle[DebugEvent.dwProcessId] =
DebugEvent.u.CreateProcessInfo.hProcess;
::CloseHandle(DebugEvent.u.CreateProcessInfo.hFile);
break;
case EXIT_PROCESS_DEBUG_EVENT: {
if (TraceExecution)
errs() << ToolName << ": Debug Event: EXIT_PROCESS_DEBUG_EVENT\n";
// If this is the process we originally created, exit with its exit
// code.
if (DebugEvent.dwProcessId == ProcessInfo.dwProcessId)
return DebugEvent.u.ExitProcess.dwExitCode;
// Otherwise cleanup any resources we have for it.
std::map<DWORD, HANDLE>::iterator ExitingProcess =
ProcessIDToHandle.find(DebugEvent.dwProcessId);
if (ExitingProcess == ProcessIDToHandle.end()) {
errs() << ToolName << ": Got unknown process id!\n";
return -1;
}
::CloseHandle(ExitingProcess->second);
ProcessIDToHandle.erase(ExitingProcess);
}
break;
case CREATE_THREAD_DEBUG_EVENT:
::CloseHandle(DebugEvent.u.CreateThread.hThread);
break;
case LOAD_DLL_DEBUG_EVENT: {
// Cleanup the file handle.
FileScopedHandle DLLFile(DebugEvent.u.LoadDll.hFile);
std::string DLLName;
ec = GetFileNameFromHandle(DLLFile, DLLName);
if (ec) {
DLLName = "<failed to get file name from file handle> : ";
DLLName += ec.message();
}
if (TraceExecution) {
errs() << ToolName << ": Debug Event: LOAD_DLL_DEBUG_EVENT\n";
errs().indent(ToolName.size()) << ": DLL Name : " << DLLName << '\n';
}
if (NoUser32 && sys::path::stem(DLLName) == "user32") {
// Program is loading user32.dll, in the applications we are testing,
// this only happens if an assert has fired. By now the message has
// already been printed, so simply close the program.
errs() << ToolName << ": user32.dll loaded!\n";
errs().indent(ToolName.size())
<< ": This probably means that assert was called. Closing "
"program to prevent message box from popping up.\n";
dwContinueStatus = DBG_CONTINUE;
::TerminateProcess(ProcessIDToHandle[DebugEvent.dwProcessId], -1);
return -1;
}
}
break;
case EXCEPTION_DEBUG_EVENT: {
// Close the application if this exception will not be handled by the
// child application.
if (TraceExecution)
errs() << ToolName << ": Debug Event: EXCEPTION_DEBUG_EVENT\n";
EXCEPTION_DEBUG_INFO &Exception = DebugEvent.u.Exception;
if (Exception.dwFirstChance > 0) {
if (TraceExecution) {
errs().indent(ToolName.size()) << ": Debug Info : ";
errs() << "First chance exception at "
<< Exception.ExceptionRecord.ExceptionAddress
<< ", exception code: "
<< ExceptionCodeToString(
Exception.ExceptionRecord.ExceptionCode)
<< " (" << Exception.ExceptionRecord.ExceptionCode << ")\n";
}
dwContinueStatus = DBG_EXCEPTION_NOT_HANDLED;
} else {
errs() << ToolName << ": Unhandled exception in: " << ProgramToRun
<< "!\n";
errs().indent(ToolName.size()) << ": location: ";
errs() << Exception.ExceptionRecord.ExceptionAddress
<< ", exception code: "
<< ExceptionCodeToString(
Exception.ExceptionRecord.ExceptionCode)
<< " (" << Exception.ExceptionRecord.ExceptionCode
<< ")\n";
dwContinueStatus = DBG_CONTINUE;
::TerminateProcess(ProcessIDToHandle[DebugEvent.dwProcessId], -1);
return -1;
}
}
break;
default:
// Do nothing.
if (TraceExecution)
errs() << ToolName << ": Debug Event: <unknown>\n";
break;
}
success = ContinueDebugEvent(DebugEvent.dwProcessId,
DebugEvent.dwThreadId,
dwContinueStatus);
if (!success) {
ec = windows_error(::GetLastError());
errs() << ToolName << ": Failed to continue debugging program: '"
<< ProgramToRun << "': " << ec.message() << '\n';
return -1;
}
dwContinueStatus = DBG_CONTINUE;
}
assert(0 && "Fell out of debug loop. This shouldn't be possible!");
return -1;
}
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