1 /*
   2  * Copyright (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "jvm.h"
  27 #include "runtime/interfaceSupport.hpp"
  28 #include "runtime/osThread.hpp"
  29 
  30 #include <signal.h>
  31 
  32 JVM_LEAF(void*, JVM_GetThreadInterruptEvent())
  33   return Thread::current()->osthread()->interrupt_event();
  34 JVM_END
  35 
  36 // sun.misc.Signal ///////////////////////////////////////////////////////////
  37 // Signal code is mostly copied from classic vm, signals_md.c   1.4 98/08/23
  38 /*
  39  * This function is included primarily as a debugging aid. If Java is
  40  * running in a console window, then pressing <CTRL-BREAK> will cause
  41  * the current state of all active threads and monitors to be written
  42  * to the console window.
  43  */
  44 
  45 JVM_ENTRY_NO_ENV(void*, JVM_RegisterSignal(jint sig, void* handler))
  46   // Copied from classic vm
  47   // signals_md.c       1.4 98/08/23
  48   void* newHandler = handler == (void *)2
  49                    ? os::user_handler()
  50                    : handler;
  51   switch (sig) {
  52    case SIGFPE:
  53      return (void *)-1; /* already used by VM */
  54    case SIGBREAK:
  55      if (!ReduceSignalUsage) return (void *)-1;
  56 
  57     /* The following signals are used for Shutdown Hooks support. However, if
  58        ReduceSignalUsage (-Xrs) is set, Shutdown Hooks must be invoked via
  59        System.exit(), Java is not allowed to use these signals, and the the
  60        user is allowed to set his own _native_ handler for these signals and
  61        invoke System.exit() as needed. Terminator.setup() is avoiding
  62        registration of these signals when -Xrs is present. */
  63    case SHUTDOWN1_SIGNAL:
  64    case SHUTDOWN2_SIGNAL:
  65      if (ReduceSignalUsage) return (void*)-1;
  66   }
  67 
  68   void* oldHandler = os::signal(sig, newHandler);
  69   if (oldHandler == os::user_handler()) {
  70       return (void *)2;
  71   } else {
  72       return oldHandler;
  73   }
  74 JVM_END
  75 
  76 
  77 JVM_ENTRY_NO_ENV(jboolean, JVM_RaiseSignal(jint sig))
  78   if (ReduceSignalUsage) {
  79     // do not allow SHUTDOWN1_SIGNAL,SHUTDOWN2_SIGNAL,BREAK_SIGNAL
  80     // to be raised when ReduceSignalUsage is set, since no handler
  81     // for them is actually registered in JVM or via JVM_RegisterSignal.
  82     if (sig == SHUTDOWN1_SIGNAL || sig == SHUTDOWN2_SIGNAL ||
  83         sig == SIGBREAK) {
  84       return JNI_FALSE;
  85     }
  86   }
  87   os::signal_raise(sig);
  88   return JNI_TRUE;
  89 JVM_END
  90 
  91