diff --git a/subprocess.h b/subprocess.h
new file mode 100644
index 0000000..92064a6
--- /dev/null
+++ b/subprocess.h
@@ -0,0 +1,79 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_SUBPROCESS_H__
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_SUBPROCESS_H__
+
+#include <map>
+#include <string>
+#include <vector>
+#include <glib.h>
+#include "chromeos/obsolete_logging.h"
+#include "base/basictypes.h"
+
+// The Subprocess class is a singleton. It's used to spawn off a subprocess
+// and get notified when the subprocess exits. The result of Exec() can
+// be saved and used to cancel the callback request. If you know you won't
+// call CancelExec(), you may safely lose the return value from Exec().
+
+namespace chromeos_update_engine {
+
+class Subprocess {
+ public:
+  static void Init() {
+    CHECK(!subprocess_singleton_);
+    subprocess_singleton_ = new Subprocess;
+  }
+   
+  typedef void(*ExecCallback)(int return_code, void *p);
+
+  // Returns a tag > 0 on success.
+  uint32 Exec(const std::vector<std::string>& cmd,
+              ExecCallback callback,
+              void* p);
+
+  // Used to cancel the callback. The process will still run to completion.
+  void CancelExec(uint32 tag);
+
+  // Executes a command synchronously. Returns true on success.
+  static bool SynchronousExec(const std::vector<std::string>& cmd,
+                              int* return_code);
+
+  // Gets the one instance
+  static Subprocess& Get() {
+    return *subprocess_singleton_;
+  }
+  
+  // Returns true iff there is at least one subprocess we're waiting on.
+  bool SubprocessInFlight() {
+    for (std::map<int, SubprocessCallbackRecord>::iterator it =
+             callback_records_.begin();
+         it != callback_records_.end(); ++it) {
+      if (it->second.callback)
+        return true;
+    }
+    return false;
+  }
+ private:
+  // The global instance
+  static Subprocess* subprocess_singleton_;
+
+  // Callback for when any subprocess terminates. This calls the user
+  // requested callback.
+  static void GChildExitedCallback(GPid pid, gint status, gpointer data);
+
+  struct SubprocessCallbackRecord {
+    ExecCallback callback;
+    void* callback_data;
+  };
+
+  std::map<int, SubprocessCallbackRecord> callback_records_;
+
+  Subprocess() {}
+  DISALLOW_COPY_AND_ASSIGN(Subprocess);
+};
+
+}  // namespace chromeos_update_engine
+
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_SUBPROCESS_H__