[Lldb-commits] [lldb] [lldb][windows] allow longer paths than MAX_PATH in GetFileNameByLoadAddress (PR #200225)

[via lldb-commits]

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@@ -555,11 +556,21 @@ static std::optional<std::string> GetFileNameByLoadAddress(HANDLE hProcess,
   }
 
   // Fallback: ask the kernel for the file backing the mapping at this address.
-  std::array<wchar_t, MAX_PATH + 1> mapped_filename;
-  if (!::GetMappedFileNameW(hProcess, base_addr, mapped_filename.data(),
-                            mapped_filename.size()))
-    return std::nullopt;
-  return ConvertNtDevicePathToDosPath(mapped_filename);
+  std::vector<wchar_t> mapped_filename(MAX_PATH + 1);
+  DWORD mapped_len = 0;
+  while (true) {
+    mapped_len = ::GetMappedFileNameW(
+        hProcess, base_addr, mapped_filename.data(), mapped_filename.size());
+    if (mapped_len > 0)
+      break;
+    if (::GetLastError() != ERROR_INSUFFICIENT_BUFFER ||
+        mapped_filename.size() >= PATHCCH_MAX_CCH)
+      return std::nullopt;
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Nerixyz wrote:

You'll need to check `GetLastError` before `mapped_len`:

> If the buffer is too small to hold the module name, the string is truncated to nSize characters (including the terminating null character), the function returns nSize, and the the last error is set to ERROR_INSUFFICIENT_BUFFER.

https://github.com/llvm/llvm-project/pull/200225