/*

 * Copyright (c) 1999, 2015, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "jvm.h"

#include "runtime/osThread.hpp"

#include <signal.h>

// sun.misc.Signal ///////////////////////////////////////////////////////////

// Signal code is mostly copied from classic vm, signals_md.c   1.4 98/08/23

/*

 * This function is included primarily as a debugging aid. If Java is

 * running in a console window, then pressing <CTRL-\\> will cause

 * the current state of all active threads and monitors to be written

 * to the console window.

 */

JVM_ENTRY_NO_ENV(void*, JVM_RegisterSignal(jint sig, void* handler))

  // Copied from classic vm

  // signals_md.c       1.4 98/08/23

  void* newHandler = handler == (void *)2

                   ? os::user_handler()

                   : handler;

  switch (sig) {

    /* The following are already used by the VM. */

    case SIGFPE:

    case SIGILL:

    case SIGSEGV:

    /* The following signal is used by the VM to dump thread stacks unless

       ReduceSignalUsage is set, in which case the user is allowed to set

       his own _native_ handler for this signal; thus, in either case,

       we do not allow JVM_RegisterSignal to change the handler. */

    case BREAK_SIGNAL:

      return (void *)-1;

    /* The following signals are used for Shutdown Hooks support. However, if

       ReduceSignalUsage (-Xrs) is set, Shutdown Hooks must be invoked via

       System.exit(), Java is not allowed to use these signals, and the the

       user is allowed to set his own _native_ handler for these signals and

       invoke System.exit() as needed. Terminator.setup() is avoiding

       registration of these signals when -Xrs is present.

       - If the HUP signal is ignored (from the nohup) command, then Java

         is not allowed to use this signal.

     */

    case SHUTDOWN1_SIGNAL:

    case SHUTDOWN2_SIGNAL:

    case SHUTDOWN3_SIGNAL:

      if (ReduceSignalUsage) return (void*)-1;

      if (os::Linux::is_sig_ignored(sig)) return (void*)1;

  }

  void* oldHandler = os::signal(sig, newHandler);

  if (oldHandler == os::user_handler()) {

      return (void *)2;

  } else {

      return oldHandler;

  }

JVM_END

JVM_ENTRY_NO_ENV(jboolean, JVM_RaiseSignal(jint sig))

  if (ReduceSignalUsage) {

    // do not allow SHUTDOWN1_SIGNAL,SHUTDOWN2_SIGNAL,SHUTDOWN3_SIGNAL,

    // BREAK_SIGNAL to be raised when ReduceSignalUsage is set, since

    // no handler for them is actually registered in JVM or via

    // JVM_RegisterSignal.

    if (sig == SHUTDOWN1_SIGNAL || sig == SHUTDOWN2_SIGNAL ||

        sig == SHUTDOWN3_SIGNAL || sig == BREAK_SIGNAL) {

      return JNI_FALSE;

    }

  }

  else if ((sig == SHUTDOWN1_SIGNAL || sig == SHUTDOWN2_SIGNAL ||

            sig == SHUTDOWN3_SIGNAL) && os::Linux::is_sig_ignored(sig)) {

    // do not allow SHUTDOWN1_SIGNAL to be raised when SHUTDOWN1_SIGNAL

    // is ignored, since no handler for them is actually registered in JVM

    // or via JVM_RegisterSignal.

    // This also applies for SHUTDOWN2_SIGNAL and SHUTDOWN3_SIGNAL

    return JNI_FALSE;

  }

  os::signal_raise(sig);

  return JNI_TRUE;

JVM_END