Added support for greylisting of system calls.

sandbox/linux/seccomp-bpf/die.h

 // Copyright (c) 2012 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_SECCOMP_BPF_DIE_H__
 #define SANDBOX_LINUX_SECCOMP_BPF_DIE_H__
 
 namespace playground2 {
 
 class Die {
  public:
   // This is the main API for using this file. Prints a error message and
   // exits with a fatal error.
   #define SANDBOX_DIE(m) Die::SandboxDie(m, __FILE__, __LINE__)
 
+  // Adds an informational message to the log file or stderr as appropriate.
+  #define SANDBOX_INFO(m) Die::SandboxInfo(m, __FILE__, __LINE__)
+
   // Terminate the program, even if the current sandbox policy prevents some
   // of the more commonly used functions used for exiting.
   // Most users would want to call SANDBOX_DIE() instead, as it logs extra
   // information. But calling ExitGroup() is correct and in some rare cases
   // preferable. So, we make it part of the public API.
   static void ExitGroup() __attribute__((noreturn));
 
   // This method gets called by SANDBOX_DIE(). There is normally no reason
   // to call it directly unless you are defining your own exiting macro.
   static void SandboxDie(const char *msg, const char *file, int line)
     __attribute__((noreturn));
 
+  // This method gets called by SANDBOX_INFO(). There is normally no reason
+  // to call it directly unless you are defining your own logging macro.
+  static void SandboxInfo(const char *msg, const char *file, int line);
+
   // Writes a message to stderr. Used as a fall-back choice, if we don't have
   // any other way to report an error.
   static void LogToStderr(const char *msg, const char *file, int line);
 
   // We generally want to run all exit handlers. This means, on SANDBOX_DIE()
   // we should be calling LOG(FATAL). But there are some situations where
   // we just need to print a message and then terminate. This would typically
   // happen in cases where we consume the error message internally (e.g. in
   // unit tests or in the supportsSeccompSandbox() method).
   static void EnableSimpleExit() { simple_exit_ = true; }
 
+  // Sometimes we need to disable all informational messages (e.g. from within
+  // unittests).
+  static void SuppressInfoMessages(bool flag) { suppress_info_ = flag; }
+
  private:
   static bool simple_exit_;
+  static bool suppress_info_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(Die);
 };
 
 }  // namespace
 
 #endif  // SANDBOX_LINUX_SECCOMP_BPF_DIE_H__