1//===-- sanitizer_symbolizer_win.cpp --------------------------------------===//
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 file is shared between AddressSanitizer and ThreadSanitizer
10// run-time libraries.
11// Windows-specific implementation of symbolizer parts.
12//===----------------------------------------------------------------------===//
13
14#include "sanitizer_platform.h"
15#if SANITIZER_WINDOWS
16
17#  include "sanitizer_dbghelp.h"
18#  include "sanitizer_symbolizer_internal.h"
19
20namespace __sanitizer {
21
22decltype(::StackWalk64) *StackWalk64;
23decltype(::SymCleanup) *SymCleanup;
24decltype(::SymFromAddr) *SymFromAddr;
25decltype(::SymFunctionTableAccess64) *SymFunctionTableAccess64;
26decltype(::SymGetLineFromAddr64) *SymGetLineFromAddr64;
27decltype(::SymGetModuleBase64) *SymGetModuleBase64;
28decltype(::SymGetSearchPathW) *SymGetSearchPathW;
29decltype(::SymInitialize) *SymInitialize;
30decltype(::SymSetOptions) *SymSetOptions;
31decltype(::SymSetSearchPathW) *SymSetSearchPathW;
32decltype(::UnDecorateSymbolName) *UnDecorateSymbolName;
33
34namespace {
35
36class WinSymbolizerTool final : public SymbolizerTool {
37 public:
38  // The constructor is provided to avoid synthesized memsets.
39  WinSymbolizerTool() {}
40
41  bool SymbolizePC(uptr addr, SymbolizedStack *stack) override;
42  bool SymbolizeData(uptr addr, DataInfo *info) override {
43    return false;
44  }
45  const char *Demangle(const char *name) override;
46};
47
48bool is_dbghelp_initialized = false;
49
50bool TrySymInitialize() {
51  SymSetOptions(SYMOPT_DEFERRED_LOADS | SYMOPT_UNDNAME | SYMOPT_LOAD_LINES);
52  return SymInitialize(GetCurrentProcess(), 0, TRUE);
53  // FIXME: We don't call SymCleanup() on exit yet - should we?
54}
55
56}  // namespace
57
58// Initializes DbgHelp library, if it's not yet initialized. Calls to this
59// function should be synchronized with respect to other calls to DbgHelp API
60// (e.g. from WinSymbolizerTool).
61void InitializeDbgHelpIfNeeded() {
62  if (is_dbghelp_initialized)
63    return;
64
65  HMODULE dbghelp = LoadLibraryA("dbghelp.dll");
66  CHECK(dbghelp && "failed to load dbghelp.dll");
67
68#define DBGHELP_IMPORT(name)                                                  \
69  do {                                                                        \
70    name =                                                                    \
71        reinterpret_cast<decltype(::name) *>(GetProcAddress(dbghelp, #name)); \
72    CHECK(name != nullptr);                                                   \
73  } while (0)
74  DBGHELP_IMPORT(StackWalk64);
75  DBGHELP_IMPORT(SymCleanup);
76  DBGHELP_IMPORT(SymFromAddr);
77  DBGHELP_IMPORT(SymFunctionTableAccess64);
78  DBGHELP_IMPORT(SymGetLineFromAddr64);
79  DBGHELP_IMPORT(SymGetModuleBase64);
80  DBGHELP_IMPORT(SymGetSearchPathW);
81  DBGHELP_IMPORT(SymInitialize);
82  DBGHELP_IMPORT(SymSetOptions);
83  DBGHELP_IMPORT(SymSetSearchPathW);
84  DBGHELP_IMPORT(UnDecorateSymbolName);
85#undef DBGHELP_IMPORT
86
87  if (!TrySymInitialize()) {
88    // OK, maybe the client app has called SymInitialize already.
89    // That's a bit unfortunate for us as all the DbgHelp functions are
90    // single-threaded and we can't coordinate with the app.
91    // FIXME: Can we stop the other threads at this point?
92    // Anyways, we have to reconfigure stuff to make sure that SymInitialize
93    // has all the appropriate options set.
94    // Cross our fingers and reinitialize DbgHelp.
95    Report("*** WARNING: Failed to initialize DbgHelp!              ***\n");
96    Report("*** Most likely this means that the app is already      ***\n");
97    Report("*** using DbgHelp, possibly with incompatible flags.    ***\n");
98    Report("*** Due to technical reasons, symbolization might crash ***\n");
99    Report("*** or produce wrong results.                           ***\n");
100    SymCleanup(GetCurrentProcess());
101    TrySymInitialize();
102  }
103  is_dbghelp_initialized = true;
104
105  // When an executable is run from a location different from the one where it
106  // was originally built, we may not see the nearby PDB files.
107  // To work around this, let's append the directory of the main module
108  // to the symbol search path.  All the failures below are not fatal.
109  const size_t kSymPathSize = 2048;
110  static wchar_t path_buffer[kSymPathSize + 1 + MAX_PATH];
111  if (!SymGetSearchPathW(GetCurrentProcess(), path_buffer, kSymPathSize)) {
112    Report("*** WARNING: Failed to SymGetSearchPathW ***\n");
113    return;
114  }
115  size_t sz = wcslen(path_buffer);
116  if (sz) {
117    CHECK_EQ(0, wcscat_s(path_buffer, L";"));
118    sz++;
119  }
120  DWORD res = GetModuleFileNameW(NULL, path_buffer + sz, MAX_PATH);
121  if (res == 0 || res == MAX_PATH) {
122    Report("*** WARNING: Failed to getting the EXE directory ***\n");
123    return;
124  }
125  // Write the zero character in place of the last backslash to get the
126  // directory of the main module at the end of path_buffer.
127  wchar_t *last_bslash = wcsrchr(path_buffer + sz, L'\\');
128  CHECK_NE(last_bslash, 0);
129  *last_bslash = L'\0';
130  if (!SymSetSearchPathW(GetCurrentProcess(), path_buffer)) {
131    Report("*** WARNING: Failed to SymSetSearchPathW\n");
132    return;
133  }
134}
135
136bool WinSymbolizerTool::SymbolizePC(uptr addr, SymbolizedStack *frame) {
137  InitializeDbgHelpIfNeeded();
138
139  // See https://docs.microsoft.com/en-us/windows/win32/debug/retrieving-symbol-information-by-address
140  InternalMmapVector<char> buffer(sizeof(SYMBOL_INFO) +
141                                  MAX_SYM_NAME * sizeof(CHAR));
142  PSYMBOL_INFO symbol = (PSYMBOL_INFO)&buffer[0];
143  symbol->SizeOfStruct = sizeof(SYMBOL_INFO);
144  symbol->MaxNameLen = MAX_SYM_NAME;
145  DWORD64 offset = 0;
146  BOOL got_objname = SymFromAddr(GetCurrentProcess(),
147                                 (DWORD64)addr, &offset, symbol);
148  if (!got_objname)
149    return false;
150
151  DWORD unused;
152  IMAGEHLP_LINE64 line_info;
153  line_info.SizeOfStruct = sizeof(IMAGEHLP_LINE64);
154  BOOL got_fileline = SymGetLineFromAddr64(GetCurrentProcess(), (DWORD64)addr,
155                                           &unused, &line_info);
156  frame->info.function = internal_strdup(symbol->Name);
157  frame->info.function_offset = (uptr)offset;
158  if (got_fileline) {
159    frame->info.file = internal_strdup(line_info.FileName);
160    frame->info.line = line_info.LineNumber;
161  }
162  // Only consider this a successful symbolization attempt if we got file info.
163  // Otherwise, try llvm-symbolizer.
164  return got_fileline;
165}
166
167const char *WinSymbolizerTool::Demangle(const char *name) {
168  CHECK(is_dbghelp_initialized);
169  static char demangle_buffer[1000];
170  if (name[0] == '\01' &&
171      UnDecorateSymbolName(name + 1, demangle_buffer, sizeof(demangle_buffer),
172                           UNDNAME_NAME_ONLY))
173    return demangle_buffer;
174  else
175    return name;
176}
177
178const char *Symbolizer::PlatformDemangle(const char *name) { return nullptr; }
179
180namespace {
181struct ScopedHandle {
182  ScopedHandle() : h_(nullptr) {}
183  explicit ScopedHandle(HANDLE h) : h_(h) {}
184  ~ScopedHandle() {
185    if (h_)
186      ::CloseHandle(h_);
187  }
188  HANDLE get() { return h_; }
189  HANDLE *receive() { return &h_; }
190  HANDLE release() {
191    HANDLE h = h_;
192    h_ = nullptr;
193    return h;
194  }
195  HANDLE h_;
196};
197} // namespace
198
199bool SymbolizerProcess::StartSymbolizerSubprocess() {
200  // Create inherited pipes for stdin and stdout.
201  ScopedHandle stdin_read, stdin_write;
202  ScopedHandle stdout_read, stdout_write;
203  SECURITY_ATTRIBUTES attrs;
204  attrs.nLength = sizeof(SECURITY_ATTRIBUTES);
205  attrs.bInheritHandle = TRUE;
206  attrs.lpSecurityDescriptor = nullptr;
207  if (!::CreatePipe(stdin_read.receive(), stdin_write.receive(), &attrs, 0) ||
208      !::CreatePipe(stdout_read.receive(), stdout_write.receive(), &attrs, 0)) {
209    VReport(2, "WARNING: %s CreatePipe failed (error code: %d)\n",
210            SanitizerToolName, path_, GetLastError());
211    return false;
212  }
213
214  // Don't inherit the writing end of stdin or the reading end of stdout.
215  if (!SetHandleInformation(stdin_write.get(), HANDLE_FLAG_INHERIT, 0) ||
216      !SetHandleInformation(stdout_read.get(), HANDLE_FLAG_INHERIT, 0)) {
217    VReport(2, "WARNING: %s SetHandleInformation failed (error code: %d)\n",
218            SanitizerToolName, path_, GetLastError());
219    return false;
220  }
221
222  // Compute the command line. Wrap double quotes around everything.
223  const char *argv[kArgVMax];
224  GetArgV(path_, argv);
225  InternalScopedString command_line;
226  for (int i = 0; argv[i]; i++) {
227    const char *arg = argv[i];
228    int arglen = internal_strlen(arg);
229    // Check that tool command lines are simple and that complete escaping is
230    // unnecessary.
231    CHECK(!internal_strchr(arg, '"') && "quotes in args unsupported");
232    CHECK(arglen > 0 && arg[arglen - 1] != '\\' &&
233          "args ending in backslash and empty args unsupported");
234    command_line.AppendF("\"%s\" ", arg);
235  }
236  VReport(3, "Launching symbolizer command: %s\n", command_line.data());
237
238  // Launch llvm-symbolizer with stdin and stdout redirected.
239  STARTUPINFOA si;
240  memset(&si, 0, sizeof(si));
241  si.cb = sizeof(si);
242  si.dwFlags |= STARTF_USESTDHANDLES;
243  si.hStdInput = stdin_read.get();
244  si.hStdOutput = stdout_write.get();
245  PROCESS_INFORMATION pi;
246  memset(&pi, 0, sizeof(pi));
247  if (!CreateProcessA(path_,               // Executable
248                      command_line.data(), // Command line
249                      nullptr,             // Process handle not inheritable
250                      nullptr,             // Thread handle not inheritable
251                      TRUE,                // Set handle inheritance to TRUE
252                      0,                   // Creation flags
253                      nullptr,             // Use parent's environment block
254                      nullptr,             // Use parent's starting directory
255                      &si, &pi)) {
256    VReport(2, "WARNING: %s failed to create process for %s (error code: %d)\n",
257            SanitizerToolName, path_, GetLastError());
258    return false;
259  }
260
261  // Process creation succeeded, so transfer handle ownership into the fields.
262  input_fd_ = stdout_read.release();
263  output_fd_ = stdin_write.release();
264
265  // The llvm-symbolizer process is responsible for quitting itself when the
266  // stdin pipe is closed, so we don't need these handles. Close them to prevent
267  // leaks. If we ever want to try to kill the symbolizer process from the
268  // parent, we'll want to hang on to these handles.
269  CloseHandle(pi.hProcess);
270  CloseHandle(pi.hThread);
271  return true;
272}
273
274static void ChooseSymbolizerTools(IntrusiveList<SymbolizerTool> *list,
275                                  LowLevelAllocator *allocator) {
276  if (!common_flags()->symbolize) {
277    VReport(2, "Symbolizer is disabled.\n");
278    return;
279  }
280
281  // Add llvm-symbolizer.
282  const char *user_path = common_flags()->external_symbolizer_path;
283
284  if (user_path && internal_strchr(user_path, '%')) {
285    char *new_path = (char *)InternalAlloc(kMaxPathLength);
286    SubstituteForFlagValue(user_path, new_path, kMaxPathLength);
287    user_path = new_path;
288  }
289
290  const char *path =
291      user_path ? user_path : FindPathToBinary("llvm-symbolizer.exe");
292  if (path) {
293    if (user_path && user_path[0] == '\0') {
294      VReport(2, "External symbolizer is explicitly disabled.\n");
295    } else {
296      VReport(2, "Using llvm-symbolizer at %spath: %s\n",
297              user_path ? "user-specified " : "", path);
298      list->push_back(new (*allocator) LLVMSymbolizer(path, allocator));
299    }
300  } else {
301    VReport(2, "External symbolizer is not present.\n");
302  }
303
304  // Add the dbghelp based symbolizer.
305  list->push_back(new(*allocator) WinSymbolizerTool());
306}
307
308Symbolizer *Symbolizer::PlatformInit() {
309  IntrusiveList<SymbolizerTool> list;
310  list.clear();
311  ChooseSymbolizerTools(&list, &symbolizer_allocator_);
312
313  return new(symbolizer_allocator_) Symbolizer(list);
314}
315
316void Symbolizer::LateInitialize() {
317  Symbolizer::GetOrInit();
318}
319
320}  // namespace __sanitizer
321
322#endif  // _WIN32
323