1/*
2 * Copyright (c) 1999, 2018, 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.inline.hpp"
28#include "runtime/osThread.hpp"
29
30#include <signal.h>
31
32
33// jdk.internal.misc.Signal ///////////////////////////////////////////////////////////
34// Signal code is mostly copied from classic vm, signals_md.c 1.4 98/08/23
35/*
36 * This function is included primarily as a debugging aid. If Java is
37 * running in a console window, then pressing <CTRL-\\> will cause
38 * the current state of all active threads and monitors to be written
39 * to the console window.
40 */
41
42JVM_ENTRY_NO_ENV(void*, JVM_RegisterSignal(jint sig, void* handler))
43 // Copied from classic vm
44 // signals_md.c 1.4 98/08/23
45 void* newHandler = handler == (void *)2
46 ? os::user_handler()
47 : handler;
48 switch (sig) {
49 /* The following are already used by the VM. */
50 case SIGFPE:
51 case SIGILL:
52 case SIGSEGV:
53
54#if defined(__APPLE__)
55 /* On Darwin, memory access errors commonly results in SIGBUS instead
56 * of SIGSEGV. */
57 case SIGBUS:
58#endif
59
60 /* The following signal is used by the VM to dump thread stacks unless
61 ReduceSignalUsage is set, in which case the user is allowed to set
62 his own _native_ handler for this signal; thus, in either case,
63 we do not allow JVM_RegisterSignal to change the handler. */
64 case BREAK_SIGNAL:
65 return (void *)-1;
66
67 /* The following signals are used for Shutdown Hooks support. However, if
68 ReduceSignalUsage (-Xrs) is set, Shutdown Hooks must be invoked via
69 System.exit(), Java is not allowed to use these signals, and the the
70 user is allowed to set his own _native_ handler for these signals and
71 invoke System.exit() as needed. Terminator.setup() is avoiding
72 registration of these signals when -Xrs is present.
73 - If the HUP signal is ignored (from the nohup) command, then Java
74 is not allowed to use this signal.
75 */
76
77 case SHUTDOWN1_SIGNAL:
78 case SHUTDOWN2_SIGNAL:
79 case SHUTDOWN3_SIGNAL:
80 if (ReduceSignalUsage) return (void*)-1;
81 if (os::Posix::is_sig_ignored(sig)) return (void*)1;
82 }
83
84 void* oldHandler = os::signal(sig, newHandler);
85 if (oldHandler == os::user_handler()) {
86 return (void *)2;
87 } else {
88 return oldHandler;
89 }
90JVM_END
91
92
93JVM_ENTRY_NO_ENV(jboolean, JVM_RaiseSignal(jint sig))
94 if (ReduceSignalUsage) {
95 // do not allow SHUTDOWN1_SIGNAL,SHUTDOWN2_SIGNAL,SHUTDOWN3_SIGNAL,
96 // BREAK_SIGNAL to be raised when ReduceSignalUsage is set, since
97 // no handler for them is actually registered in JVM or via
98 // JVM_RegisterSignal.
99 if (sig == SHUTDOWN1_SIGNAL || sig == SHUTDOWN2_SIGNAL ||
100 sig == SHUTDOWN3_SIGNAL || sig == BREAK_SIGNAL) {
101 return JNI_FALSE;
102 }
103 }
104 else if ((sig == SHUTDOWN1_SIGNAL || sig == SHUTDOWN2_SIGNAL ||
105 sig == SHUTDOWN3_SIGNAL) && os::Posix::is_sig_ignored(sig)) {
106 // do not allow SHUTDOWN1_SIGNAL to be raised when SHUTDOWN1_SIGNAL
107 // is ignored, since no handler for them is actually registered in JVM
108 // or via JVM_RegisterSignal.
109 // This also applies for SHUTDOWN2_SIGNAL and SHUTDOWN3_SIGNAL
110 return JNI_FALSE;
111 }
112
113 os::signal_raise(sig);
114 return JNI_TRUE;
115JVM_END
116
117