Linux sandbox: add basic Yama support

sandbox/linux/services/scoped_process.h

+// Copyright 2014 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 SANDBOX_LINUX_SERVICES_SCOPED_PROCESS_H_
+#define SANDBOX_LINUX_SERVICES_SCOPED_PROCESS_H_
+
+#include "base/basictypes.h"
+#include "base/callback_forward.h"
+#include "base/process/process_handle.h"
+
+namespace sandbox {
+
+// fork() a child process that will run a Closure.
+// After the Closure has run, the child will pause forever. If this object
+// is detroyed, the child will be destroyed, even if the closure did not
+// finish running. It's ok to signal the child from outside of this class to
+// destroy it.
+// This class cannot be instanciated from a multi-threaded process, as it needs
+// to fork().
+class ScopedProcess {
+ public:
+  // A new process will be created and |child_callback| will run in the child
+  // process. This callback is allowed to terminate the process or to simply
+  // return. If the callback returns, the process will wait forever.
+  explicit ScopedProcess(const base::Closure& child_callback);
+  ~ScopedProcess();
+
+  // Wait for the process to exit.
+  // |got_signaled| tells how to interpret the return value: either as an exit
+  // code, or as a signal number.
+  // When this returns, the process will still not have been reaped and will
+  // survive as a zombie for the lifetime of this object. This method can be
+  // called multiple times.
+  int WaitForExit(bool* got_signaled);
+
+  // Wait for the |child_callback| passed at construction to run. Return false
+  // if |child_callback| did not finish running and we know it never will (for
+  // instance the child crashed or used _exit()).
+  bool WaitForClosureToRun();
+  base::ProcessId GetPid() { return child_process_id_; }
+
+ private:
+  bool IsOriginalProcess();
+
+  base::ProcessId child_process_id_;
+  base::ProcessId process_id_;
+  int pipe_fds_[2];
+  DISALLOW_COPY_AND_ASSIGN(ScopedProcess);
+};
+
+}  // namespace sandbox
+
+#endif  // SANDBOX_LINUX_SERVICES_SCOPED_PROCESS_H_