1 files changed, 94 insertions, 0 deletions
diff --git a/browser/app/pbproxy/pbproxy.cpp b/browser/app/pbproxy/pbproxy.cpp
new file mode 100644
index 0000000000..841cd654a1
--- /dev/null
+++ b/browser/app/pbproxy/pbproxy.cpp
@@ -0,0 +1,94 @@
+/* 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 <windows.h>
+#include <processthreadsapi.h>
+#include <winbase.h>
+#include <winuser.h>
+#include <shlwapi.h>
+#include <string>
+
+// Max command line length, per CreateProcessW docs
+#define MAX_CMD_LENGTH 32767
+#define EXTRA_ERR_MSG_LENGTH 39
+#define ERR_GET_OUR_PATH L"844fa30e-0860-11ed-898b-373276936058"
+#define ERR_GET_APP_DIR L"811237de-0904-11ed-8745-c7c269742323"
+#define ERR_GET_APP_EXE L"8964fd30-0860-11ed-8374-576505ba4488"
+#define ERR_LAUNCHING_APP L"89d2ca2c-0860-11ed-883c-bf345b8391bc"
+
+void raiseError(DWORD err, std::wstring uuid) {
+  LPWSTR winerr;
+  if (err && ::FormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER |
+                                  FORMAT_MESSAGE_FROM_SYSTEM |
+                                  FORMAT_MESSAGE_IGNORE_INSERTS,
+                              nullptr, err, 0, (LPWSTR)&winerr, 0, nullptr)) {
+    std::wstring errmsg(winerr);
+    errmsg += L"\n\n" + uuid;
+    ::MessageBoxW(nullptr, errmsg.c_str(), MOZ_APP_NAME " private_browsing.exe",
+                  MB_OK | MB_ICONERROR | MB_SETFOREGROUND);
+  } else {
+    ::MessageBoxW(nullptr, uuid.c_str(), MOZ_APP_NAME " private_browsing.exe",
+                  MB_OK | MB_ICONERROR | MB_SETFOREGROUND);
+  }
+}
+
+/*
+ * A very simple wrapper that always launches Firefox in Private Browsing
+ * mode. Any arguments given to this program will be forwarded to Firefox,
+ * as well the information provided by GetStartupInfoW() (the latter is mainly
+ * done to ensure that Firefox's `launch_method` Telemetry works, which
+ * depends on shortcut information).
+ *
+ * Any errors that happen during this process will pop up a MessageBox
+ * with a Windows error (if present) and a unique UUID for debugability --
+ * but these are very unlikely to be seen in practice.
+ */
+int WINAPI wWinMain(HINSTANCE, HINSTANCE, LPWSTR aCmdLine, int) {
+  wchar_t app[MAX_PATH];
+  DWORD ret = GetModuleFileNameW(nullptr, app, MAX_PATH);
+  if (!ret ||
+      (ret == MAX_PATH && ::GetLastError() == ERROR_INSUFFICIENT_BUFFER)) {
+    ret = ::GetLastError();
+    raiseError(ret, ERR_GET_OUR_PATH);
+    return ret;
+  }
+  if (!PathRemoveFileSpecW(app)) {
+    raiseError(0, ERR_GET_APP_DIR);
+    return 1;
+  }
+  if (!PathAppendW(app, MOZ_APP_NAME L".exe")) {
+    raiseError(0, ERR_GET_APP_EXE);
+    return 1;
+  }
+
+  std::wstring cmdLine(L"\"");
+  cmdLine += app;
+  cmdLine += L"\" -private-window";
+  if (wcslen(aCmdLine) > 0) {
+    cmdLine += L" ";
+    cmdLine += aCmdLine;
+  }
+  DWORD creationFlags = CREATE_UNICODE_ENVIRONMENT;
+  // Mainly used to pass along shortcut information to ensure
+  // launch_method Telemetry will be accurate.
+  STARTUPINFOW startupInfo = {0};
+  startupInfo.cb = sizeof(STARTUPINFOW);
+  GetStartupInfoW(&startupInfo);
+  PROCESS_INFORMATION pi;
+
+  bool rv =
+      ::CreateProcessW(app, cmdLine.data(), nullptr, nullptr, FALSE,
+                       creationFlags, nullptr, nullptr, &startupInfo, &pi);
+
+  if (!rv) {
+    ret = ::GetLastError();
+    raiseError(ret, ERR_LAUNCHING_APP);
+    return ret;
+  }
+
+  ::CloseHandle(pi.hProcess);
+  ::CloseHandle(pi.hThread);
+
+  return 0;
+}