jvm_bsd.cpp revision 9302:6e76f1f75b89 
1/*
2 * Copyright (c) 1999, 2015, 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
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    /* The following signal is used by the VM to dump thread stacks unless
55       ReduceSignalUsage is set, in which case the user is allowed to set
56       his own _native_ handler for this signal; thus, in either case,
57       we do not allow JVM_RegisterSignal to change the handler. */
58    case BREAK_SIGNAL:
59      return (void *)-1;
60
61    /* The following signals are used for Shutdown Hooks support. However, if
62       ReduceSignalUsage (-Xrs) is set, Shutdown Hooks must be invoked via
63       System.exit(), Java is not allowed to use these signals, and the the
64       user is allowed to set his own _native_ handler for these signals and
65       invoke System.exit() as needed. Terminator.setup() is avoiding
66       registration of these signals when -Xrs is present.
67       - If the HUP signal is ignored (from the nohup) command, then Java
68         is not allowed to use this signal.
69     */
70
71    case SHUTDOWN1_SIGNAL:
72    case SHUTDOWN2_SIGNAL:
73    case SHUTDOWN3_SIGNAL:
74      if (ReduceSignalUsage) return (void*)-1;
75      if (os::Bsd::is_sig_ignored(sig)) return (void*)1;
76  }
77
78  void* oldHandler = os::signal(sig, newHandler);
79  if (oldHandler == os::user_handler()) {
80      return (void *)2;
81  } else {
82      return oldHandler;
83  }
84JVM_END
85
86
87JVM_ENTRY_NO_ENV(jboolean, JVM_RaiseSignal(jint sig))
88  if (ReduceSignalUsage) {
89    // do not allow SHUTDOWN1_SIGNAL,SHUTDOWN2_SIGNAL,SHUTDOWN3_SIGNAL,
90    // BREAK_SIGNAL to be raised when ReduceSignalUsage is set, since
91    // no handler for them is actually registered in JVM or via
92    // JVM_RegisterSignal.
93    if (sig == SHUTDOWN1_SIGNAL || sig == SHUTDOWN2_SIGNAL ||
94        sig == SHUTDOWN3_SIGNAL || sig == BREAK_SIGNAL) {
95      return JNI_FALSE;
96    }
97  }
98  else if ((sig == SHUTDOWN1_SIGNAL || sig == SHUTDOWN2_SIGNAL ||
99            sig == SHUTDOWN3_SIGNAL) && os::Bsd::is_sig_ignored(sig)) {
100    // do not allow SHUTDOWN1_SIGNAL to be raised when SHUTDOWN1_SIGNAL
101    // is ignored, since no handler for them is actually registered in JVM
102    // or via JVM_RegisterSignal.
103    // This also applies for SHUTDOWN2_SIGNAL and SHUTDOWN3_SIGNAL
104    return JNI_FALSE;
105  }
106
107  os::signal_raise(sig);
108  return JNI_TRUE;
109JVM_END
110
111/*
112  All the defined signal names for Bsd.
113
114  NOTE that not all of these names are accepted by our Java implementation
115
116  Via an existing claim by the VM, sigaction restrictions, or
117  the "rules of Unix" some of these names will be rejected at runtime.
118  For example the VM sets up to handle USR1, sigaction returns EINVAL for
119  STOP, and Bsd simply doesn't allow catching of KILL.
120
121  Here are the names currently accepted by a user of sun.misc.Signal with
122  1.4.1 (ignoring potential interaction with use of chaining, etc):
123
124    HUP, INT, TRAP, ABRT, IOT, BUS, USR2, PIPE, ALRM, TERM, STKFLT,
125    CLD, CHLD, CONT, TSTP, TTIN, TTOU, URG, XCPU, XFSZ, VTALRM, PROF,
126    WINCH, POLL, IO, PWR, SYS
127
128*/
129
130struct siglabel {
131  const char *name;
132  int   number;
133};
134
135struct siglabel siglabels[] = {
136  /* derived from /usr/include/bits/signum.h on RH7.2 */
137   "HUP",       SIGHUP,         /* Hangup (POSIX).  */
138  "INT",        SIGINT,         /* Interrupt (ANSI).  */
139  "QUIT",       SIGQUIT,        /* Quit (POSIX).  */
140  "ILL",        SIGILL,         /* Illegal instruction (ANSI).  */
141  "TRAP",       SIGTRAP,        /* Trace trap (POSIX).  */
142  "ABRT",       SIGABRT,        /* Abort (ANSI).  */
143  "EMT",        SIGEMT,         /* EMT trap  */
144  "FPE",        SIGFPE,         /* Floating-point exception (ANSI).  */
145  "KILL",       SIGKILL,        /* Kill, unblockable (POSIX).  */
146  "BUS",        SIGBUS,         /* BUS error (4.2 BSD).  */
147  "SEGV",       SIGSEGV,        /* Segmentation violation (ANSI).  */
148  "SYS",        SIGSYS,         /* Bad system call. Only on some Bsden! */
149  "PIPE",       SIGPIPE,        /* Broken pipe (POSIX).  */
150  "ALRM",       SIGALRM,        /* Alarm clock (POSIX).  */
151  "TERM",       SIGTERM,        /* Termination (ANSI).  */
152  "URG",        SIGURG,         /* Urgent condition on socket (4.2 BSD).  */
153  "STOP",       SIGSTOP,        /* Stop, unblockable (POSIX).  */
154  "TSTP",       SIGTSTP,        /* Keyboard stop (POSIX).  */
155  "CONT",       SIGCONT,        /* Continue (POSIX).  */
156  "CHLD",       SIGCHLD,        /* Child status has changed (POSIX).  */
157  "TTIN",       SIGTTIN,        /* Background read from tty (POSIX).  */
158  "TTOU",       SIGTTOU,        /* Background write to tty (POSIX).  */
159  "IO",         SIGIO,          /* I/O now possible (4.2 BSD).  */
160  "XCPU",       SIGXCPU,        /* CPU limit exceeded (4.2 BSD).  */
161  "XFSZ",       SIGXFSZ,        /* File size limit exceeded (4.2 BSD).  */
162  "VTALRM",     SIGVTALRM,      /* Virtual alarm clock (4.2 BSD).  */
163  "PROF",       SIGPROF,        /* Profiling alarm clock (4.2 BSD).  */
164  "WINCH",      SIGWINCH,       /* Window size change (4.3 BSD, Sun).  */
165  "INFO",       SIGINFO,        /* Information request.  */
166  "USR1",       SIGUSR1,        /* User-defined signal 1 (POSIX).  */
167  "USR2",       SIGUSR2         /* User-defined signal 2 (POSIX).  */
168  };
169
170JVM_ENTRY_NO_ENV(jint, JVM_FindSignal(const char *name))
171
172  /* find and return the named signal's number */
173
174  for(uint i=0; i<ARRAY_SIZE(siglabels); i++)
175    if(!strcmp(name, siglabels[i].name))
176      return siglabels[i].number;
177
178  return -1;
179
180JVM_END
181
182// used by os::exception_name()
183extern bool signal_name(int signo, char* buf, size_t len) {
184  for(uint i = 0; i < ARRAY_SIZE(siglabels); i++) {
185    if (signo == siglabels[i].number) {
186      jio_snprintf(buf, len, "SIG%s", siglabels[i].name);
187      return true;
188    }
189  }
190  return false;
191}
192