1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/os/solaris/vm/jsig.c Sat Dec 01 00:00:00 2007 +0000
1.3 @@ -0,0 +1,273 @@
1.4 +/*
1.5 + * Copyright 2001-2003 Sun Microsystems, Inc. All Rights Reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
1.23 + * CA 95054 USA or visit www.sun.com if you need additional information or
1.24 + * have any questions.
1.25 + *
1.26 + */
1.27 +
1.28 +/* CopyrightVersion 1.2 */
1.29 +
1.30 +/* This is a special library that should be loaded before libc &
1.31 + * libthread to interpose the signal handler installation functions:
1.32 + * sigaction(), signal(), sigset().
1.33 + * Used for signal-chaining. See RFE 4381843.
1.34 + */
1.35 +
1.36 +#include <stdlib.h>
1.37 +#include <stdio.h>
1.38 +#include <string.h>
1.39 +#include <signal.h>
1.40 +#include <dlfcn.h>
1.41 +#include <thread.h>
1.42 +#include <synch.h>
1.43 +#include "jvm_solaris.h"
1.44 +
1.45 +#define bool int
1.46 +#define true 1
1.47 +#define false 0
1.48 +
1.49 +static struct sigaction *sact = (struct sigaction *)NULL; /* saved signal handlers */
1.50 +static sigset_t jvmsigs;
1.51 +
1.52 +/* used to synchronize the installation of signal handlers */
1.53 +static mutex_t mutex = DEFAULTMUTEX;
1.54 +static cond_t cond = DEFAULTCV;
1.55 +static thread_t tid = 0;
1.56 +
1.57 +typedef void (*sa_handler_t)(int);
1.58 +typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
1.59 +typedef sa_handler_t (*signal_t)(int, sa_handler_t);
1.60 +typedef int (*sigaction_t)(int, const struct sigaction *, struct sigaction *);
1.61 +
1.62 +static signal_t os_signal = 0; /* os's version of signal()/sigset() */
1.63 +static sigaction_t os_sigaction = 0; /* os's version of sigaction() */
1.64 +
1.65 +static bool jvm_signal_installing = false;
1.66 +static bool jvm_signal_installed = false;
1.67 +
1.68 +
1.69 +/* assume called within signal_lock */
1.70 +static void allocate_sact() {
1.71 + size_t maxsignum;
1.72 + maxsignum = SIGRTMAX;
1.73 + if (sact == NULL) {
1.74 + sact = (struct sigaction *)malloc((maxsignum+1) * (size_t)sizeof(struct sigaction));
1.75 + memset(sact, 0, (maxsignum+1) * (size_t)sizeof(struct sigaction));
1.76 + }
1.77 +
1.78 + if (sact == NULL) {
1.79 + printf("%s\n", "libjsig.so unable to allocate memory");
1.80 + exit(0);
1.81 + }
1.82 +
1.83 + sigemptyset(&jvmsigs);
1.84 +}
1.85 +
1.86 +static void signal_lock() {
1.87 + mutex_lock(&mutex);
1.88 + /* When the jvm is installing its set of signal handlers, threads
1.89 + * other than the jvm thread should wait */
1.90 + if (jvm_signal_installing) {
1.91 + if (tid != thr_self()) {
1.92 + cond_wait(&cond, &mutex);
1.93 + }
1.94 + }
1.95 +}
1.96 +
1.97 +static void signal_unlock() {
1.98 + mutex_unlock(&mutex);
1.99 +}
1.100 +
1.101 +static sa_handler_t call_os_signal(int sig, sa_handler_t disp,
1.102 + bool is_sigset) {
1.103 + if (os_signal == NULL) {
1.104 + if (!is_sigset) {
1.105 + os_signal = (signal_t)dlsym(RTLD_NEXT, "signal");
1.106 + } else {
1.107 + os_signal = (signal_t)dlsym(RTLD_NEXT, "sigset");
1.108 + }
1.109 + if (os_signal == NULL) {
1.110 + printf("%s\n", dlerror());
1.111 + exit(0);
1.112 + }
1.113 + }
1.114 + return (*os_signal)(sig, disp);
1.115 +}
1.116 +
1.117 +static void save_signal_handler(int sig, sa_handler_t disp, bool is_sigset) {
1.118 + sigset_t set;
1.119 + if (sact == NULL) {
1.120 + allocate_sact();
1.121 + }
1.122 + sact[sig].sa_handler = disp;
1.123 + sigemptyset(&set);
1.124 + sact[sig].sa_mask = set;
1.125 + if (!is_sigset) {
1.126 + sact[sig].sa_flags = SA_NODEFER;
1.127 + if (sig != SIGILL && sig != SIGTRAP && sig != SIGPWR) {
1.128 + sact[sig].sa_flags |= SA_RESETHAND;
1.129 + }
1.130 + } else {
1.131 + sact[sig].sa_flags = 0;
1.132 + }
1.133 +}
1.134 +
1.135 +static sa_handler_t set_signal(int sig, sa_handler_t disp, bool is_sigset) {
1.136 + sa_handler_t oldhandler;
1.137 + bool sigblocked;
1.138 +
1.139 + signal_lock();
1.140 + if (sact == NULL) {
1.141 + allocate_sact();
1.142 + }
1.143 +
1.144 + if (jvm_signal_installed && sigismember(&jvmsigs, sig)) {
1.145 + /* jvm has installed its signal handler for this signal. */
1.146 + /* Save the handler. Don't really install it. */
1.147 + if (is_sigset) {
1.148 + /* We won't honor the SIG_HOLD request to change the signal mask */
1.149 + sigblocked = sigismember(&(sact[sig].sa_mask), sig);
1.150 + }
1.151 + oldhandler = sact[sig].sa_handler;
1.152 + save_signal_handler(sig, disp, is_sigset);
1.153 +
1.154 + if (is_sigset && sigblocked) {
1.155 + oldhandler = SIG_HOLD;
1.156 + }
1.157 +
1.158 + signal_unlock();
1.159 + return oldhandler;
1.160 + } else if (jvm_signal_installing) {
1.161 + /* jvm is installing its signal handlers. Install the new
1.162 + * handlers and save the old ones. jvm uses sigaction().
1.163 + * Leave the piece here just in case. */
1.164 + oldhandler = call_os_signal(sig, disp, is_sigset);
1.165 + save_signal_handler(sig, oldhandler, is_sigset);
1.166 +
1.167 + /* Record the signals used by jvm */
1.168 + sigaddset(&jvmsigs, sig);
1.169 +
1.170 + signal_unlock();
1.171 + return oldhandler;
1.172 + } else {
1.173 + /* jvm has no relation with this signal (yet). Install the
1.174 + * the handler. */
1.175 + oldhandler = call_os_signal(sig, disp, is_sigset);
1.176 +
1.177 + signal_unlock();
1.178 + return oldhandler;
1.179 + }
1.180 +}
1.181 +
1.182 +sa_handler_t signal(int sig, sa_handler_t disp) {
1.183 + return set_signal(sig, disp, false);
1.184 +}
1.185 +
1.186 +sa_handler_t sigset(int sig, sa_handler_t disp) {
1.187 + return set_signal(sig, disp, true);
1.188 +}
1.189 +
1.190 +static int call_os_sigaction(int sig, const struct sigaction *act,
1.191 + struct sigaction *oact) {
1.192 + if (os_sigaction == NULL) {
1.193 + os_sigaction = (sigaction_t)dlsym(RTLD_NEXT, "sigaction");
1.194 + if (os_sigaction == NULL) {
1.195 + printf("%s\n", dlerror());
1.196 + exit(0);
1.197 + }
1.198 + }
1.199 + return (*os_sigaction)(sig, act, oact);
1.200 +}
1.201 +
1.202 +int sigaction(int sig, const struct sigaction *act, struct sigaction *oact) {
1.203 + int res;
1.204 + struct sigaction oldAct;
1.205 +
1.206 + signal_lock();
1.207 +
1.208 + if (sact == NULL ) {
1.209 + allocate_sact();
1.210 + }
1.211 + if (jvm_signal_installed && sigismember(&jvmsigs, sig)) {
1.212 + /* jvm has installed its signal handler for this signal. */
1.213 + /* Save the handler. Don't really install it. */
1.214 + if (oact != NULL) {
1.215 + *oact = sact[sig];
1.216 + }
1.217 + if (act != NULL) {
1.218 + sact[sig] = *act;
1.219 + }
1.220 +
1.221 + signal_unlock();
1.222 + return 0;
1.223 + } else if (jvm_signal_installing) {
1.224 + /* jvm is installing its signal handlers. Install the new
1.225 + * handlers and save the old ones. */
1.226 + res = call_os_sigaction(sig, act, &oldAct);
1.227 + sact[sig] = oldAct;
1.228 + if (oact != NULL) {
1.229 + *oact = oldAct;
1.230 + }
1.231 +
1.232 + /* Record the signals used by jvm */
1.233 + sigaddset(&jvmsigs, sig);
1.234 +
1.235 + signal_unlock();
1.236 + return res;
1.237 + } else {
1.238 + /* jvm has no relation with this signal (yet). Install the
1.239 + * the handler. */
1.240 + res = call_os_sigaction(sig, act, oact);
1.241 +
1.242 + signal_unlock();
1.243 + return res;
1.244 + }
1.245 +}
1.246 +
1.247 +/* The four functions for the jvm to call into */
1.248 +void JVM_begin_signal_setting() {
1.249 + signal_lock();
1.250 + jvm_signal_installing = true;
1.251 + tid = thr_self();
1.252 + signal_unlock();
1.253 +}
1.254 +
1.255 +void JVM_end_signal_setting() {
1.256 + signal_lock();
1.257 + jvm_signal_installed = true;
1.258 + jvm_signal_installing = false;
1.259 + cond_broadcast(&cond);
1.260 + signal_unlock();
1.261 +}
1.262 +
1.263 +struct sigaction *JVM_get_signal_action(int sig) {
1.264 + if (sact == NULL) {
1.265 + allocate_sact();
1.266 + }
1.267 + /* Does race condition make sense here? */
1.268 + if (sigismember(&jvmsigs, sig)) {
1.269 + return &sact[sig];
1.270 + }
1.271 + return NULL;
1.272 +}
1.273 +
1.274 +int JVM_get_libjsig_version() {
1.275 + return JSIG_VERSION_1_4_1;
1.276 +}
