1 /*
2 * Copyright (c) 1999, 2011, 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
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 INTERRUPT_SIGNAL:
51 case SIGFPE:
52 case SIGILL:
53 case SIGSEGV:
54
55 /* The following signal is used by the VM to dump thread stacks unless
56 ReduceSignalUsage is set, in which case the user is allowed to set
57 his own _native_ handler for this signal; thus, in either case,
58 we do not allow JVM_RegisterSignal to change the handler. */
59 case BREAK_SIGNAL:
60 return (void *)-1;
61
62 /* The following signals are used for Shutdown Hooks support. However, if
63 ReduceSignalUsage (-Xrs) is set, Shutdown Hooks must be invoked via
64 System.exit(), Java is not allowed to use these signals, and the the
65 user is allowed to set his own _native_ handler for these signals and
66 invoke System.exit() as needed. Terminator.setup() is avoiding
67 registration of these signals when -Xrs is present.
68 - If the HUP signal is ignored (from the nohup) command, then Java
69 is not allowed to use this signal.
70 */
71
72 case SHUTDOWN1_SIGNAL:
73 case SHUTDOWN2_SIGNAL:
74 case SHUTDOWN3_SIGNAL:
75 if (ReduceSignalUsage) return (void*)-1;
76 if (os::Linux::is_sig_ignored(sig)) return (void*)1;
77 }
78
79 void* oldHandler = os::signal(sig, newHandler);
80 if (oldHandler == os::user_handler()) {
81 return (void *)2;
82 } else {
83 return oldHandler;
84 }
85 JVM_END
86
87
88 JVM_ENTRY_NO_ENV(jboolean, JVM_RaiseSignal(jint sig))
89 if (ReduceSignalUsage) {
90 // do not allow SHUTDOWN1_SIGNAL,SHUTDOWN2_SIGNAL,SHUTDOWN3_SIGNAL,
91 // BREAK_SIGNAL to be raised when ReduceSignalUsage is set, since
92 // no handler for them is actually registered in JVM or via
93 // JVM_RegisterSignal.
94 if (sig == SHUTDOWN1_SIGNAL || sig == SHUTDOWN2_SIGNAL ||
95 sig == SHUTDOWN3_SIGNAL || sig == BREAK_SIGNAL) {
96 return JNI_FALSE;
97 }
98 }
99 else if ((sig == SHUTDOWN1_SIGNAL || sig == SHUTDOWN2_SIGNAL ||
100 sig == SHUTDOWN3_SIGNAL) && os::Linux::is_sig_ignored(sig)) {
101 // do not allow SHUTDOWN1_SIGNAL to be raised when SHUTDOWN1_SIGNAL
102 // is ignored, since no handler for them is actually registered in JVM
103 // or via JVM_RegisterSignal.
104 // This also applies for SHUTDOWN2_SIGNAL and SHUTDOWN3_SIGNAL
105 return JNI_FALSE;
106 }
107
108 os::signal_raise(sig);
109 return JNI_TRUE;
110 JVM_END
111
112 /*
113 All the defined signal names for Linux.
114
115 NOTE that not all of these names are accepted by our Java implementation
116
117 Via an existing claim by the VM, sigaction restrictions, or
118 the "rules of Unix" some of these names will be rejected at runtime.
119 For example the VM sets up to handle USR1, sigaction returns EINVAL for
120 STOP, and Linux simply doesn't allow catching of KILL.
121
122 Here are the names currently accepted by a user of sun.misc.Signal with
123 1.4.1 (ignoring potential interaction with use of chaining, etc):
124
125 HUP, INT, TRAP, ABRT, IOT, BUS, USR2, PIPE, ALRM, TERM, STKFLT,
126 CLD, CHLD, CONT, TSTP, TTIN, TTOU, URG, XCPU, XFSZ, VTALRM, PROF,
127 WINCH, POLL, IO, PWR, SYS
128
129 */
130
131 struct siglabel {
132 const char *name;
133 int number;
134 };
135
136 struct siglabel siglabels[] = {
137 /* derived from /usr/include/bits/signum.h on RH7.2 */
138 "HUP", SIGHUP, /* Hangup (POSIX). */
139 "INT", SIGINT, /* Interrupt (ANSI). */
140 "QUIT", SIGQUIT, /* Quit (POSIX). */
141 "ILL", SIGILL, /* Illegal instruction (ANSI). */
142 "TRAP", SIGTRAP, /* Trace trap (POSIX). */
143 "ABRT", SIGABRT, /* Abort (ANSI). */
144 "IOT", SIGIOT, /* IOT trap (4.2 BSD). */
145 "BUS", SIGBUS, /* BUS error (4.2 BSD). */
146 "FPE", SIGFPE, /* Floating-point exception (ANSI). */
147 "KILL", SIGKILL, /* Kill, unblockable (POSIX). */
148 "USR1", SIGUSR1, /* User-defined signal 1 (POSIX). */
149 "SEGV", SIGSEGV, /* Segmentation violation (ANSI). */
150 "USR2", SIGUSR2, /* User-defined signal 2 (POSIX). */
151 "PIPE", SIGPIPE, /* Broken pipe (POSIX). */
152 "ALRM", SIGALRM, /* Alarm clock (POSIX). */
153 "TERM", SIGTERM, /* Termination (ANSI). */
154 #ifdef SIGSTKFLT
155 "STKFLT", SIGSTKFLT, /* Stack fault. */
156 #endif
157 "CLD", SIGCLD, /* Same as SIGCHLD (System V). */
158 "CHLD", SIGCHLD, /* Child status has changed (POSIX). */
159 "CONT", SIGCONT, /* Continue (POSIX). */
160 "STOP", SIGSTOP, /* Stop, unblockable (POSIX). */
161 "TSTP", SIGTSTP, /* Keyboard stop (POSIX). */
162 "TTIN", SIGTTIN, /* Background read from tty (POSIX). */
163 "TTOU", SIGTTOU, /* Background write to tty (POSIX). */
164 "URG", SIGURG, /* Urgent condition on socket (4.2 BSD). */
165 "XCPU", SIGXCPU, /* CPU limit exceeded (4.2 BSD). */
166 "XFSZ", SIGXFSZ, /* File size limit exceeded (4.2 BSD). */
167 "VTALRM", SIGVTALRM, /* Virtual alarm clock (4.2 BSD). */
168 "PROF", SIGPROF, /* Profiling alarm clock (4.2 BSD). */
169 "WINCH", SIGWINCH, /* Window size change (4.3 BSD, Sun). */
170 "POLL", SIGPOLL, /* Pollable event occurred (System V). */
171 "IO", SIGIO, /* I/O now possible (4.2 BSD). */
172 "PWR", SIGPWR, /* Power failure restart (System V). */
173 #ifdef SIGSYS
174 "SYS", SIGSYS /* Bad system call. Only on some Linuxen! */
175 #endif
176 };
177
178 JVM_ENTRY_NO_ENV(jint, JVM_FindSignal(const char *name))
179
180 /* find and return the named signal's number */
181
182 for(uint i=0; i<ARRAY_SIZE(siglabels); i++)
183 if(!strcmp(name, siglabels[i].name))
184 return siglabels[i].number;
185
186 return -1;
187
188 JVM_END
189
190 // used by os::exception_name()
191 extern bool signal_name(int signo, char* buf, size_t len) {
192 for(uint i = 0; i < ARRAY_SIZE(siglabels); i++) {
193 if (signo == siglabels[i].number) {
194 jio_snprintf(buf, len, "SIG%s", siglabels[i].name);
195 return true;
196 }
197 }
198 return false;
199 }