Added support for sigreturn() and rt_sigreturn(). On x86-32, this is...

sandbox/linux/seccomp/ioctl.cc

 // Copyright (c) 2010 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 "debug.h"
 #include "sandbox_impl.h"
 
 namespace playground {
 
 long Sandbox::sandbox_ioctl(int d, int req, void *arg) {
@@ skipping 30 matching lines @@
     die("Failed to read parameters for ioctl() [process]");
   }
   int rc = -EINVAL;
   switch (ioctl_req.req) {
     case TCGETS:
     case TIOCGWINSZ:
       SecureMem::sendSystemCall(threadFdPub, false, -1, mem, __NR_ioctl,
                                 ioctl_req.d, ioctl_req.req, ioctl_req.arg);
       return true;
     default:
-      std::cerr << "Unsupported ioctl: 0x" << std::hex << ioctl_req.req <<
-          std::endl;
+      if (Debug::isEnabled()) {
+        char buf[80];
+        sprintf(buf, "Unsupported ioctl: 0x%04X\n", ioctl_req.req);
+        Debug::message(buf);
+      }
       SecureMem::abandonSystemCall(threadFd, rc);
       return false;
   }
 }
 
 } // namespace