author | hseigel |
Fri, 05 Oct 2018 08:50:49 -0400 | |
changeset 52024 | 257ae7e677c3 |
parent 51677 | ddc976897c75 |
child 52482 | 8a88bbeb1d1c |
permissions | -rw-r--r-- |
49561 | 1 |
/* |
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* Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved. |
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* Copyright (c) 2012, 2015 SAP SE. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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* |
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*/ |
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/* This is a special library that should be loaded before libc & |
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* libthread to interpose the signal handler installation functions: |
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* sigaction(), signal(), sigset(). |
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* Used for signal-chaining. See RFE 4381843. |
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*/ |
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#include "jni.h" |
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#ifdef SOLARIS |
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/* Our redeclarations of the system functions must not have a less |
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* restrictive linker scoping, so we have to declare them as JNIEXPORT |
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* before including signal.h */ |
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#include "sys/signal.h" |
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JNIEXPORT void (*signal(int sig, void (*disp)(int)))(int); |
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JNIEXPORT void (*sigset(int sig, void (*disp)(int)))(int); |
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JNIEXPORT int sigaction(int sig, const struct sigaction *act, struct sigaction *oact); |
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#endif |
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#include <dlfcn.h> |
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#include <errno.h> |
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#include <pthread.h> |
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#include <signal.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#if (__STDC_VERSION__ >= 199901L) |
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#include <stdbool.h> |
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#else |
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#define bool int |
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#define true 1 |
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#define false 0 |
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#endif |
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#ifdef SOLARIS |
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#define MAX_SIGNALS (SIGRTMAX+1) |
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/* On solaris, MAX_SIGNALS is a macro, not a constant, so we must allocate sact dynamically. */ |
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static struct sigaction *sact = (struct sigaction *)NULL; /* saved signal handlers */ |
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#else |
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#define MAX_SIGNALS NSIG |
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static struct sigaction sact[MAX_SIGNALS]; /* saved signal handlers */ |
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#endif |
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static sigset_t jvmsigs; /* Signals used by jvm. */ |
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#ifdef MACOSX |
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static __thread bool reentry = false; /* prevent reentry deadlock (per-thread) */ |
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#endif |
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/* Used to synchronize the installation of signal handlers. */ |
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static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; |
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static pthread_cond_t cond = PTHREAD_COND_INITIALIZER; |
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static pthread_t tid = 0; |
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typedef void (*sa_handler_t)(int); |
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typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); |
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typedef sa_handler_t (*signal_function_t)(int, sa_handler_t); |
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typedef int (*sigaction_t)(int, const struct sigaction *, struct sigaction *); |
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static signal_function_t os_signal = 0; /* os's version of signal()/sigset() */ |
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static sigaction_t os_sigaction = 0; /* os's version of sigaction() */ |
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static bool jvm_signal_installing = false; |
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static bool jvm_signal_installed = false; |
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/* assume called within signal_lock */ |
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static void allocate_sact() { |
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#ifdef SOLARIS |
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if (sact == NULL) { |
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sact = (struct sigaction *)malloc((MAX_SIGNALS) * (size_t)sizeof(struct sigaction)); |
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if (sact == NULL) { |
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printf("%s\n", "libjsig.so unable to allocate memory"); |
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exit(0); |
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} |
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memset(sact, 0, (MAX_SIGNALS) * (size_t)sizeof(struct sigaction)); |
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} |
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#endif |
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} |
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static void signal_lock() { |
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pthread_mutex_lock(&mutex); |
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/* When the jvm is installing its set of signal handlers, threads |
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* other than the jvm thread should wait. */ |
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if (jvm_signal_installing) { |
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if (tid != pthread_self()) { |
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pthread_cond_wait(&cond, &mutex); |
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} |
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} |
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} |
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static void signal_unlock() { |
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pthread_mutex_unlock(&mutex); |
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} |
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static sa_handler_t call_os_signal(int sig, sa_handler_t disp, |
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bool is_sigset) { |
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sa_handler_t res; |
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if (os_signal == NULL) { |
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if (!is_sigset) { |
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os_signal = (signal_function_t)dlsym(RTLD_NEXT, "signal"); |
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} else { |
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os_signal = (signal_function_t)dlsym(RTLD_NEXT, "sigset"); |
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} |
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if (os_signal == NULL) { |
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printf("%s\n", dlerror()); |
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exit(0); |
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} |
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} |
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#ifdef MACOSX |
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/* On macosx, the OS implementation of signal calls sigaction. |
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* Make sure we do not deadlock with ourself. (See JDK-8072147). */ |
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reentry = true; |
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#endif |
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res = (*os_signal)(sig, disp); |
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#ifdef MACOSX |
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reentry = false; |
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#endif |
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return res; |
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} |
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static void save_signal_handler(int sig, sa_handler_t disp, bool is_sigset) { |
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sigset_t set; |
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sact[sig].sa_handler = disp; |
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sigemptyset(&set); |
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sact[sig].sa_mask = set; |
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if (!is_sigset) { |
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#ifdef SOLARIS |
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sact[sig].sa_flags = SA_NODEFER; |
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if (sig != SIGILL && sig != SIGTRAP && sig != SIGPWR) { |
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sact[sig].sa_flags |= SA_RESETHAND; |
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} |
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#else |
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sact[sig].sa_flags = 0; |
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#endif |
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} else { |
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sact[sig].sa_flags = 0; |
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} |
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} |
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static sa_handler_t set_signal(int sig, sa_handler_t disp, bool is_sigset) { |
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sa_handler_t oldhandler; |
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bool sigused; |
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bool sigblocked; |
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signal_lock(); |
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allocate_sact(); |
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sigused = sigismember(&jvmsigs, sig); |
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if (jvm_signal_installed && sigused) { |
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/* jvm has installed its signal handler for this signal. */ |
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/* Save the handler. Don't really install it. */ |
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if (is_sigset) { |
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sigblocked = sigismember(&(sact[sig].sa_mask), sig); |
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} |
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oldhandler = sact[sig].sa_handler; |
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save_signal_handler(sig, disp, is_sigset); |
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#ifdef SOLARIS |
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if (is_sigset && sigblocked) { |
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/* We won't honor the SIG_HOLD request to change the signal mask */ |
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oldhandler = SIG_HOLD; |
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} |
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#endif |
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signal_unlock(); |
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return oldhandler; |
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} else if (jvm_signal_installing) { |
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/* jvm is installing its signal handlers. Install the new |
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* handlers and save the old ones. jvm uses sigaction(). |
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* Leave the piece here just in case. */ |
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oldhandler = call_os_signal(sig, disp, is_sigset); |
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save_signal_handler(sig, oldhandler, is_sigset); |
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/* Record the signals used by jvm */ |
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sigaddset(&jvmsigs, sig); |
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signal_unlock(); |
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return oldhandler; |
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} else { |
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/* jvm has no relation with this signal (yet). Install the |
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* the handler. */ |
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oldhandler = call_os_signal(sig, disp, is_sigset); |
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signal_unlock(); |
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return oldhandler; |
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} |
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} |
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JNIEXPORT sa_handler_t signal(int sig, sa_handler_t disp) { |
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if (sig < 0 || sig >= MAX_SIGNALS) { |
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errno = EINVAL; |
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return SIG_ERR; |
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} |
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return set_signal(sig, disp, false); |
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} |
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JNIEXPORT sa_handler_t sigset(int sig, sa_handler_t disp) { |
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#ifdef _ALLBSD_SOURCE |
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printf("sigset() is not supported by BSD"); |
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exit(0); |
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#else |
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if (sig < 0 || sig >= MAX_SIGNALS) { |
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errno = EINVAL; |
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return (sa_handler_t)-1; |
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} |
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return set_signal(sig, disp, true); |
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#endif |
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} |
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static int call_os_sigaction(int sig, const struct sigaction *act, |
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struct sigaction *oact) { |
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if (os_sigaction == NULL) { |
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os_sigaction = (sigaction_t)dlsym(RTLD_NEXT, "sigaction"); |
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if (os_sigaction == NULL) { |
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printf("%s\n", dlerror()); |
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exit(0); |
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} |
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} |
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return (*os_sigaction)(sig, act, oact); |
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} |
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JNIEXPORT int sigaction(int sig, const struct sigaction *act, struct sigaction *oact) { |
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int res; |
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bool sigused; |
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struct sigaction oldAct; |
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if (sig < 0 || sig >= MAX_SIGNALS) { |
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errno = EINVAL; |
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return -1; |
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} |
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#ifdef MACOSX |
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if (reentry) { |
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return call_os_sigaction(sig, act, oact); |
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} |
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#endif |
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signal_lock(); |
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allocate_sact(); |
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sigused = sigismember(&jvmsigs, sig); |
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if (jvm_signal_installed && sigused) { |
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/* jvm has installed its signal handler for this signal. */ |
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/* Save the handler. Don't really install it. */ |
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if (oact != NULL) { |
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*oact = sact[sig]; |
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} |
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if (act != NULL) { |
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sact[sig] = *act; |
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} |
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signal_unlock(); |
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return 0; |
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} else if (jvm_signal_installing) { |
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/* jvm is installing its signal handlers. Install the new |
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* handlers and save the old ones. */ |
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res = call_os_sigaction(sig, act, &oldAct); |
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sact[sig] = oldAct; |
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if (oact != NULL) { |
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*oact = oldAct; |
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} |
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/* Record the signals used by jvm. */ |
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sigaddset(&jvmsigs, sig); |
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signal_unlock(); |
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return res; |
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} else { |
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/* jvm has no relation with this signal (yet). Install the |
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* the handler. */ |
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res = call_os_sigaction(sig, act, oact); |
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signal_unlock(); |
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return res; |
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} |
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} |
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/* The three functions for the jvm to call into. */ |
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52024
257ae7e677c3
8211438: [Testbug] runtime/XCheckJniJsig/XCheckJSig.java looks for libjsig in wrong location
hseigel
parents:
51677
diff
changeset
|
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JNIEXPORT void JVM_begin_signal_setting() { |
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signal_lock(); |
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sigemptyset(&jvmsigs); |
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jvm_signal_installing = true; |
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tid = pthread_self(); |
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signal_unlock(); |
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} |
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||
52024
257ae7e677c3
8211438: [Testbug] runtime/XCheckJniJsig/XCheckJSig.java looks for libjsig in wrong location
hseigel
parents:
51677
diff
changeset
|
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JNIEXPORT void JVM_end_signal_setting() { |
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signal_lock(); |
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jvm_signal_installed = true; |
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jvm_signal_installing = false; |
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pthread_cond_broadcast(&cond); |
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signal_unlock(); |
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} |
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||
52024
257ae7e677c3
8211438: [Testbug] runtime/XCheckJniJsig/XCheckJSig.java looks for libjsig in wrong location
hseigel
parents:
51677
diff
changeset
|
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JNIEXPORT struct sigaction *JVM_get_signal_action(int sig) { |
49561 | 332 |
allocate_sact(); |
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/* Does race condition make sense here? */ |
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if (sigismember(&jvmsigs, sig)) { |
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return &sact[sig]; |
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} |
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return NULL; |
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} |