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 // sun.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 42 JVM_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 } 90 JVM_END 91 92 93 JVM_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; 115 JVM_END 116