Added support for greylisting of system calls.

sandbox/linux/seccomp-bpf/die.cc

 // 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.
 
 #include <string>
 
 #include "sandbox/linux/seccomp-bpf/sandbox_bpf.h"
+#include "sandbox/linux/seccomp-bpf/syscall.h"
 
 
 namespace playground2 {
 
 void Die::ExitGroup() {
   // exit_group() should exit our program. After all, it is defined as a
   // function that doesn't return. But things can theoretically go wrong.
   // Especially, since we are dealing with system call filters. Continuing
   // execution would be very bad in most cases where ExitGroup() gets called.
   // So, we'll try a few other strategies too.
-  syscall(__NR_exit_group, 1);
+  Syscall(__NR_exit_group, 1);
 
   // We have no idea what our run-time environment looks like. So, signal
   // handlers might or might not do the right thing. Try to reset settings
   // to a defined state; but we have not way to verify whether we actually
   // succeeded in doing so. Nonetheless, triggering a fatal signal could help
   // us terminate.
   signal(SIGSEGV, SIG_DFL);
-  syscall(__NR_prctl, PR_SET_DUMPABLE, (void *)0, (void *)0, (void *)0);
+  Syscall(__NR_prctl, PR_SET_DUMPABLE, (void *)0, (void *)0, (void *)0);
   if (*(volatile char *)0) { }
 
   // If there is no way for us to ask for the program to exit, the next
   // best thing we can do is to loop indefinitely. Maybe, somebody will notice
   // and file a bug...
   // We in fact retry the system call inside of our loop so that it will
   // stand out when somebody tries to diagnose the problem by using "strace".
   for (;;) {
-    syscall(__NR_exit_group, 1);
+    Syscall(__NR_exit_group, 1);
   }
 }
 
 void Die::SandboxDie(const char *msg, const char *file, int line) {
   if (simple_exit_) {
     LogToStderr(msg, file, line);
   } else {
     #if defined(SECCOMP_BPF_STANDALONE)
       Die::LogToStderr(msg, file, line);
     #else
       logging::LogMessage(file, line, logging::LOG_FATAL).stream() << msg;
     #endif
   }
   ExitGroup();
 }
 
+void Die::SandboxInfo(const char *msg, const char *file, int line) {
+  if (!suppress_info_) {
+  #if defined(SECCOMP_BPF_STANDALONE)
+    Die::LogToStderr(msg, file, line);
+  #else
+    logging::LogMessage(file, line, logging::LOG_INFO).stream() << msg;
+  #endif
+  }
+}
+
 void Die::LogToStderr(const char *msg, const char *file, int line) {
   if (msg) {
     char buf[40];
     snprintf(buf, sizeof(buf), "%d", line);
     std::string s = std::string(file) + ":" + buf + ":" + msg + "\n";
 
     // No need to loop. Short write()s are unlikely and if they happen we
     // probably prefer them over a loop that blocks.
-    if (HANDLE_EINTR(write(2, s.c_str(), s.length()))) { }
+    if (HANDLE_EINTR(Syscall(__NR_write, 2, s.c_str(), s.length()))) { }
   }
 }
 
-bool Die::simple_exit_ = false;
+bool Die::simple_exit_   = false;
+bool Die::suppress_info_ = false;
 
 }  // namespace