1 /*
2 * Copyright (c) 1999, 2007, 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 "incls/_precompiled.incl"
26 #include "incls/_jvm_linux.cpp.incl"
27
28 #include <signal.h>
29
30 /*
31 * FIXME: This is temporary hack to keep Linux Runtime.exec()
32 * code happy. See $JDK/src/linux/native/java/lang/UnixProcess_md.c
33 */
34 int _JVM_native_threads = 1;
35
36 // sun.misc.Signal ///////////////////////////////////////////////////////////
37 // Signal code is mostly copied from classic vm, signals_md.c 1.4 98/08/23
38 /*
39 * This function is included primarily as a debugging aid. If Java is
40 * running in a console window, then pressing <CTRL-\\> will cause
41 * the current state of all active threads and monitors to be written
42 * to the console window.
43 */
44
45 JVM_ENTRY_NO_ENV(void*, JVM_RegisterSignal(jint sig, void* handler))
46 // Copied from classic vm
47 // signals_md.c 1.4 98/08/23
48 void* newHandler = handler == (void *)2
49 ? os::user_handler()
50 : handler;
51 switch (sig) {
52 /* The following are already used by the VM. */
53 case INTERRUPT_SIGNAL:
54 case SIGFPE:
55 case SIGILL:
56 case SIGSEGV:
57
58 /* The following signal is used by the VM to dump thread stacks unless
59 ReduceSignalUsage is set, in which case the user is allowed to set
60 his own _native_ handler for this signal; thus, in either case,
61 we do not allow JVM_RegisterSignal to change the handler. */
62 case BREAK_SIGNAL:
63 return (void *)-1;
64
65 /* The following signals are used for Shutdown Hooks support. However, if
66 ReduceSignalUsage (-Xrs) is set, Shutdown Hooks must be invoked via
67 System.exit(), Java is not allowed to use these signals, and the the
68 user is allowed to set his own _native_ handler for these signals and
69 invoke System.exit() as needed. Terminator.setup() is avoiding
70 registration of these signals when -Xrs is present.
71 - If the HUP signal is ignored (from the nohup) command, then Java
72 is not allowed to use this signal.
73 */
74
75 case SHUTDOWN1_SIGNAL:
76 case SHUTDOWN2_SIGNAL:
77 case SHUTDOWN3_SIGNAL:
78 if (ReduceSignalUsage) return (void*)-1;
79 if (os::Linux::is_sig_ignored(sig)) return (void*)1;
80 }
81
82 void* oldHandler = os::signal(sig, newHandler);
83 if (oldHandler == os::user_handler()) {
84 return (void *)2;
85 } else {
86 return oldHandler;
87 }
88 JVM_END
89
90
91 JVM_ENTRY_NO_ENV(jboolean, JVM_RaiseSignal(jint sig))
92 if (ReduceSignalUsage) {
93 // do not allow SHUTDOWN1_SIGNAL,SHUTDOWN2_SIGNAL,SHUTDOWN3_SIGNAL,
94 // BREAK_SIGNAL to be raised when ReduceSignalUsage is set, since
95 // no handler for them is actually registered in JVM or via
96 // JVM_RegisterSignal.
97 if (sig == SHUTDOWN1_SIGNAL || sig == SHUTDOWN2_SIGNAL ||
98 sig == SHUTDOWN3_SIGNAL || sig == BREAK_SIGNAL) {
99 return JNI_FALSE;
100 }
101 }
102 else if ((sig == SHUTDOWN1_SIGNAL || sig == SHUTDOWN2_SIGNAL ||
103 sig == SHUTDOWN3_SIGNAL) && os::Linux::is_sig_ignored(sig)) {
104 // do not allow SHUTDOWN1_SIGNAL to be raised when SHUTDOWN1_SIGNAL
105 // is ignored, since no handler for them is actually registered in JVM
106 // or via JVM_RegisterSignal.
107 // This also applies for SHUTDOWN2_SIGNAL and SHUTDOWN3_SIGNAL
108 return JNI_FALSE;
109 }
110
111 os::signal_raise(sig);
112 return JNI_TRUE;
113 JVM_END
114
115 /*
116 All the defined signal names for Linux.
117
118 NOTE that not all of these names are accepted by our Java implementation
119
120 Via an existing claim by the VM, sigaction restrictions, or
121 the "rules of Unix" some of these names will be rejected at runtime.
122 For example the VM sets up to handle USR1, sigaction returns EINVAL for
123 STOP, and Linux simply doesn't allow catching of KILL.
124
125 Here are the names currently accepted by a user of sun.misc.Signal with
126 1.4.1 (ignoring potential interaction with use of chaining, etc):
127
128 HUP, INT, TRAP, ABRT, IOT, BUS, USR2, PIPE, ALRM, TERM, STKFLT,
129 CLD, CHLD, CONT, TSTP, TTIN, TTOU, URG, XCPU, XFSZ, VTALRM, PROF,
130 WINCH, POLL, IO, PWR, SYS
131
132 */
133
134 struct siglabel {
135 const char *name;
136 int number;
137 };
138
139 struct siglabel siglabels[] = {
140 /* derived from /usr/include/bits/signum.h on RH7.2 */
141 "HUP", SIGHUP, /* Hangup (POSIX). */
142 "INT", SIGINT, /* Interrupt (ANSI). */
143 "QUIT", SIGQUIT, /* Quit (POSIX). */
144 "ILL", SIGILL, /* Illegal instruction (ANSI). */
145 "TRAP", SIGTRAP, /* Trace trap (POSIX). */
146 "ABRT", SIGABRT, /* Abort (ANSI). */
147 "IOT", SIGIOT, /* IOT trap (4.2 BSD). */
148 "BUS", SIGBUS, /* BUS error (4.2 BSD). */
149 "FPE", SIGFPE, /* Floating-point exception (ANSI). */
150 "KILL", SIGKILL, /* Kill, unblockable (POSIX). */
151 "USR1", SIGUSR1, /* User-defined signal 1 (POSIX). */
152 "SEGV", SIGSEGV, /* Segmentation violation (ANSI). */
153 "USR2", SIGUSR2, /* User-defined signal 2 (POSIX). */
154 "PIPE", SIGPIPE, /* Broken pipe (POSIX). */
155 "ALRM", SIGALRM, /* Alarm clock (POSIX). */
156 "TERM", SIGTERM, /* Termination (ANSI). */
157 #ifdef SIGSTKFLT
158 "STKFLT", SIGSTKFLT, /* Stack fault. */
159 #endif
160 "CLD", SIGCLD, /* Same as SIGCHLD (System V). */
161 "CHLD", SIGCHLD, /* Child status has changed (POSIX). */
162 "CONT", SIGCONT, /* Continue (POSIX). */
163 "STOP", SIGSTOP, /* Stop, unblockable (POSIX). */
164 "TSTP", SIGTSTP, /* Keyboard stop (POSIX). */
165 "TTIN", SIGTTIN, /* Background read from tty (POSIX). */
166 "TTOU", SIGTTOU, /* Background write to tty (POSIX). */
167 "URG", SIGURG, /* Urgent condition on socket (4.2 BSD). */
168 "XCPU", SIGXCPU, /* CPU limit exceeded (4.2 BSD). */
169 "XFSZ", SIGXFSZ, /* File size limit exceeded (4.2 BSD). */
170 "VTALRM", SIGVTALRM, /* Virtual alarm clock (4.2 BSD). */
171 "PROF", SIGPROF, /* Profiling alarm clock (4.2 BSD). */
172 "WINCH", SIGWINCH, /* Window size change (4.3 BSD, Sun). */
173 "POLL", SIGPOLL, /* Pollable event occurred (System V). */
174 "IO", SIGIO, /* I/O now possible (4.2 BSD). */
175 "PWR", SIGPWR, /* Power failure restart (System V). */
176 #ifdef SIGSYS
177 "SYS", SIGSYS /* Bad system call. Only on some Linuxen! */
178 #endif
179 };
180
181 JVM_ENTRY_NO_ENV(jint, JVM_FindSignal(const char *name))
182
183 /* find and return the named signal's number */
184
185 for(uint i=0; i<ARRAY_SIZE(siglabels); i++)
186 if(!strcmp(name, siglabels[i].name))
187 return siglabels[i].number;
188
189 return -1;
190
191 JVM_END
192
193 // used by os::exception_name()
194 extern bool signal_name(int signo, char* buf, size_t len) {
195 for(uint i = 0; i < ARRAY_SIZE(siglabels); i++) {
196 if (signo == siglabels[i].number) {
197 jio_snprintf(buf, len, "SIG%s", siglabels[i].name);
198 return true;
199 }
200 }
201 return false;
202 }