1 files changed, 127 insertions, 0 deletions
diff --git a/xpcom/io/FileUtilsWin.cpp b/xpcom/io/FileUtilsWin.cpp
new file mode 100644
index 0000000000..5bf7e4c968
--- /dev/null
+++ b/xpcom/io/FileUtilsWin.cpp
@@ -0,0 +1,127 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "FileUtilsWin.h"
+
+#include <windows.h>
+#include <psapi.h>
+
+#include "base/process_util.h"
+#include "mozilla/ProfilerLabels.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/Unused.h"
+#include "nsWindowsHelpers.h"
+
+namespace mozilla {
+
+bool HandleToFilename(HANDLE aHandle, const LARGE_INTEGER& aOffset,
+                      nsAString& aFilename) {
+  AUTO_PROFILER_LABEL("HandletoFilename", OTHER);
+
+  aFilename.Truncate();
+  // This implementation is nice because it uses fully documented APIs that
+  // are available on all Windows versions that we support.
+  nsAutoHandle fileMapping(
+      CreateFileMapping(aHandle, nullptr, PAGE_READONLY, 0, 1, nullptr));
+  if (!fileMapping) {
+    return false;
+  }
+  const auto view = MapViewOfFile(fileMapping, FILE_MAP_READ, aOffset.HighPart,
+                                  aOffset.LowPart, 1);
+  if (!view) {
+    return false;
+  }
+  const auto cleanup =
+      MakeScopeExit([&]() { mozilla::Unused << UnmapViewOfFile(view); });
+
+  nsAutoString mappedFilename;
+  DWORD len = 0;
+  SetLastError(ERROR_SUCCESS);
+  do {
+    mappedFilename.SetLength(mappedFilename.Length() + MAX_PATH);
+    len = GetMappedFileNameW(GetCurrentProcess(), view, mappedFilename.get(),
+                             mappedFilename.Length());
+  } while (!len && GetLastError() == ERROR_INSUFFICIENT_BUFFER);
+  if (!len) {
+    return false;
+  }
+  mappedFilename.Truncate(len);
+  return NtPathToDosPath(mappedFilename, aFilename);
+}
+
+template <class T>
+struct RVAMap {
+  RVAMap(HANDLE map, DWORD offset) {
+    SYSTEM_INFO info;
+    GetSystemInfo(&info);
+
+    DWORD alignedOffset =
+        (offset / info.dwAllocationGranularity) * info.dwAllocationGranularity;
+
+    MOZ_ASSERT(offset - alignedOffset < info.dwAllocationGranularity, "Wtf");
+
+    mRealView = ::MapViewOfFile(map, FILE_MAP_READ, 0, alignedOffset,
+                                sizeof(T) + (offset - alignedOffset));
+
+    mMappedView =
+        mRealView
+            ? reinterpret_cast<T*>((char*)mRealView + (offset - alignedOffset))
+            : nullptr;
+  }
+  ~RVAMap() {
+    if (mRealView) {
+      ::UnmapViewOfFile(mRealView);
+    }
+  }
+  operator const T*() const { return mMappedView; }
+  const T* operator->() const { return mMappedView; }
+
+ private:
+  const T* mMappedView;
+  void* mRealView;
+};
+
+uint32_t GetExecutableArchitecture(const wchar_t* aPath) {
+  nsAutoHandle file(::CreateFileW(aPath, GENERIC_READ, FILE_SHARE_READ, nullptr,
+                                  OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL,
+                                  nullptr));
+  if (!file) {
+    return base::PROCESS_ARCH_INVALID;
+  }
+
+  nsAutoHandle map(
+      ::CreateFileMappingW(file, nullptr, PAGE_READONLY, 0, 0, nullptr));
+  if (!map) {
+    return base::PROCESS_ARCH_INVALID;
+  }
+
+  RVAMap<IMAGE_DOS_HEADER> peHeader(map, 0);
+  if (!peHeader) {
+    return base::PROCESS_ARCH_INVALID;
+  }
+
+  RVAMap<IMAGE_NT_HEADERS> ntHeader(map, peHeader->e_lfanew);
+  if (!ntHeader) {
+    return base::PROCESS_ARCH_INVALID;
+  }
+
+  switch (ntHeader->FileHeader.Machine) {
+    case IMAGE_FILE_MACHINE_I386:
+      return base::PROCESS_ARCH_I386;
+    case IMAGE_FILE_MACHINE_AMD64:
+      return base::PROCESS_ARCH_X86_64;
+    case IMAGE_FILE_MACHINE_ARM64:
+      return base::PROCESS_ARCH_ARM_64;
+    case IMAGE_FILE_MACHINE_ARM:
+    case IMAGE_FILE_MACHINE_ARMNT:
+    case IMAGE_FILE_MACHINE_THUMB:
+      return base::PROCESS_ARCH_ARM;
+    default:
+      return base::PROCESS_ARCH_INVALID;
+  }
+}
+
+}  // namespace mozilla