1/*
2 * Copyright (c) 1998, 2015, 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 "prims/jvm.h"
27#include "runtime/interfaceSupport.hpp"
28#include "runtime/osThread.hpp"
29
30#include <signal.h>
31
32// sun.misc.Signal ///////////////////////////////////////////////////////////
33// Signal code is mostly copied from classic vm, signals_md.c   1.4 98/08/23
34/*
35 * This function is included primarily as a debugging aid. If Java is
36 * running in a console window, then pressing <CTRL-\\> will cause
37 * the current state of all active threads and monitors to be written
38 * to the console window.
39 */
40
41JVM_ENTRY_NO_ENV(void*, JVM_RegisterSignal(jint sig, void* handler))
42  // Copied from classic vm
43  // signals_md.c       1.4 98/08/23
44  void* newHandler = handler == (void *)2
45                   ? os::user_handler()
46                   : handler;
47  switch (sig) {
48    /* The following are already used by the VM. */
49    case SIGFPE:
50    case SIGILL:
51    case SIGSEGV:
52
53    /* The following signal is used by the VM to dump thread stacks unless
54       ReduceSignalUsage is set, in which case the user is allowed to set
55       his own _native_ handler for this signal; thus, in either case,
56       we do not allow JVM_RegisterSignal to change the handler. */
57    case BREAK_SIGNAL:
58      return (void *)-1;
59
60    /* The following signals are used for Shutdown Hooks support. However, if
61       ReduceSignalUsage (-Xrs) is set, Shutdown Hooks must be invoked via
62       System.exit(), Java is not allowed to use these signals, and the the
63       user is allowed to set his own _native_ handler for these signals and
64       invoke System.exit() as needed. Terminator.setup() is avoiding
65       registration of these signals when -Xrs is present.
66       - If the HUP signal is ignored (from the nohup) command, then Java
67         is not allowed to use this signal.
68     */
69    case SHUTDOWN1_SIGNAL:
70    case SHUTDOWN2_SIGNAL:
71    case SHUTDOWN3_SIGNAL:
72      if (ReduceSignalUsage) return (void*)-1;
73      if (os::Solaris::is_sig_ignored(sig)) return (void*)1;
74  }
75
76  void* oldHandler = os::signal(sig, newHandler);
77  if (oldHandler == os::user_handler()) {
78      return (void *)2;
79  } else {
80      return oldHandler;
81  }
82JVM_END
83
84
85JVM_ENTRY_NO_ENV(jboolean, JVM_RaiseSignal(jint sig))
86  if (ReduceSignalUsage) {
87    // do not allow SHUTDOWN1_SIGNAL,SHUTDOWN2_SIGNAL,SHUTDOWN3_SIGNAL,
88    // BREAK_SIGNAL to be raised when ReduceSignalUsage is set, since
89    // no handler for them is actually registered in JVM or via
90    // JVM_RegisterSignal.
91    if (sig == SHUTDOWN1_SIGNAL || sig == SHUTDOWN2_SIGNAL ||
92        sig == SHUTDOWN3_SIGNAL || sig == BREAK_SIGNAL) {
93      return JNI_FALSE;
94    }
95  }
96  else if ((sig == SHUTDOWN1_SIGNAL || sig == SHUTDOWN2_SIGNAL ||
97            sig == SHUTDOWN3_SIGNAL) && os::Solaris::is_sig_ignored(sig)) {
98    // do not allow SHUTDOWN1_SIGNAL to be raised when SHUTDOWN1_SIGNAL
99    // is ignored, since no handler for them is actually registered in JVM
100    // or via JVM_RegisterSignal.
101    // This also applies for SHUTDOWN2_SIGNAL and SHUTDOWN3_SIGNAL
102    return JNI_FALSE;
103  }
104
105  os::signal_raise(sig);
106  return JNI_TRUE;
107JVM_END
108
109