1 /*
2 * Copyright (c) 1999, 2010, 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 * FIXME: This is temporary hack to keep Linux Runtime.exec()
34 * code happy. See $JDK/src/linux/native/java/lang/UnixProcess_md.c
35 */
36 int _JVM_native_threads = 1;
37
38 // sun.misc.Signal ///////////////////////////////////////////////////////////
39 // Signal code is mostly copied from classic vm, signals_md.c 1.4 98/08/23
40 /*
41 * This function is included primarily as a debugging aid. If Java is
42 * running in a console window, then pressing <CTRL-\\> will cause
43 * the current state of all active threads and monitors to be written
44 * to the console window.
45 */
46
47 JVM_ENTRY_NO_ENV(void*, JVM_RegisterSignal(jint sig, void* handler))
48 // Copied from classic vm
49 // signals_md.c 1.4 98/08/23
50 void* newHandler = handler == (void *)2
51 ? os::user_handler()
52 : handler;
53 switch (sig) {
54 /* The following are already used by the VM. */
55 case INTERRUPT_SIGNAL:
56 case SIGFPE:
57 case SIGILL:
58 case SIGSEGV:
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::Linux::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::Linux::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
117 /*
118 All the defined signal names for Linux.
119
120 NOTE that not all of these names are accepted by our Java implementation
121
122 Via an existing claim by the VM, sigaction restrictions, or
123 the "rules of Unix" some of these names will be rejected at runtime.
124 For example the VM sets up to handle USR1, sigaction returns EINVAL for
125 STOP, and Linux simply doesn't allow catching of KILL.
126
127 Here are the names currently accepted by a user of sun.misc.Signal with
128 1.4.1 (ignoring potential interaction with use of chaining, etc):
129
130 HUP, INT, TRAP, ABRT, IOT, BUS, USR2, PIPE, ALRM, TERM, STKFLT,
131 CLD, CHLD, CONT, TSTP, TTIN, TTOU, URG, XCPU, XFSZ, VTALRM, PROF,
132 WINCH, POLL, IO, PWR, SYS
133
134 */
135
136 struct siglabel {
137 const char *name;
138 int number;
139 };
140
141 struct siglabel siglabels[] = {
142 /* derived from /usr/include/bits/signum.h on RH7.2 */
143 "HUP", SIGHUP, /* Hangup (POSIX). */
144 "INT", SIGINT, /* Interrupt (ANSI). */
145 "QUIT", SIGQUIT, /* Quit (POSIX). */
146 "ILL", SIGILL, /* Illegal instruction (ANSI). */
147 "TRAP", SIGTRAP, /* Trace trap (POSIX). */
148 "ABRT", SIGABRT, /* Abort (ANSI). */
149 "IOT", SIGIOT, /* IOT trap (4.2 BSD). */
150 "BUS", SIGBUS, /* BUS error (4.2 BSD). */
151 "FPE", SIGFPE, /* Floating-point exception (ANSI). */
152 "KILL", SIGKILL, /* Kill, unblockable (POSIX). */
153 "USR1", SIGUSR1, /* User-defined signal 1 (POSIX). */
154 "SEGV", SIGSEGV, /* Segmentation violation (ANSI). */
155 "USR2", SIGUSR2, /* User-defined signal 2 (POSIX). */
156 "PIPE", SIGPIPE, /* Broken pipe (POSIX). */
157 "ALRM", SIGALRM, /* Alarm clock (POSIX). */
158 "TERM", SIGTERM, /* Termination (ANSI). */
159 #ifdef SIGSTKFLT
160 "STKFLT", SIGSTKFLT, /* Stack fault. */
161 #endif
162 "CLD", SIGCLD, /* Same as SIGCHLD (System V). */
163 "CHLD", SIGCHLD, /* Child status has changed (POSIX). */
164 "CONT", SIGCONT, /* Continue (POSIX). */
165 "STOP", SIGSTOP, /* Stop, unblockable (POSIX). */
166 "TSTP", SIGTSTP, /* Keyboard stop (POSIX). */
167 "TTIN", SIGTTIN, /* Background read from tty (POSIX). */
168 "TTOU", SIGTTOU, /* Background write to tty (POSIX). */
169 "URG", SIGURG, /* Urgent condition on socket (4.2 BSD). */
170 "XCPU", SIGXCPU, /* CPU limit exceeded (4.2 BSD). */
171 "XFSZ", SIGXFSZ, /* File size limit exceeded (4.2 BSD). */
172 "VTALRM", SIGVTALRM, /* Virtual alarm clock (4.2 BSD). */
173 "PROF", SIGPROF, /* Profiling alarm clock (4.2 BSD). */
174 "WINCH", SIGWINCH, /* Window size change (4.3 BSD, Sun). */
175 "POLL", SIGPOLL, /* Pollable event occurred (System V). */
176 "IO", SIGIO, /* I/O now possible (4.2 BSD). */
177 "PWR", SIGPWR, /* Power failure restart (System V). */
178 #ifdef SIGSYS
179 "SYS", SIGSYS /* Bad system call. Only on some Linuxen! */
180 #endif
181 };
182
183 JVM_ENTRY_NO_ENV(jint, JVM_FindSignal(const char *name))
184
185 /* find and return the named signal's number */
186
187 for(uint i=0; i<ARRAY_SIZE(siglabels); i++)
188 if(!strcmp(name, siglabels[i].name))
189 return siglabels[i].number;
190
191 return -1;
192
193 JVM_END
194
195 // used by os::exception_name()
196 extern bool signal_name(int signo, char* buf, size_t len) {
197 for(uint i = 0; i < ARRAY_SIZE(siglabels); i++) {
198 if (signo == siglabels[i].number) {
199 jio_snprintf(buf, len, "SIG%s", siglabels[i].name);
200 return true;
201 }
202 }
203 return false;
204 }