--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/unix/native/libjsig/jsig.c Tue Apr 10 19:46:02 2018 +0200
@@ -0,0 +1,326 @@
+/*
+ * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2015 SAP SE. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+/* This is a special library that should be loaded before libc &
+ * libthread to interpose the signal handler installation functions:
+ * sigaction(), signal(), sigset().
+ * Used for signal-chaining. See RFE 4381843.
+ */
+
+#include <dlfcn.h>
+#include <errno.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if (__STDC_VERSION__ >= 199901L)
+ #include <stdbool.h>
+#else
+ #define bool int
+ #define true 1
+ #define false 0
+#endif
+
+#ifdef SOLARIS
+#define MAX_SIGNALS (SIGRTMAX+1)
+
+/* On solaris, MAX_SIGNALS is a macro, not a constant, so we must allocate sact dynamically. */
+static struct sigaction *sact = (struct sigaction *)NULL; /* saved signal handlers */
+#else
+#define MAX_SIGNALS NSIG
+
+static struct sigaction sact[MAX_SIGNALS]; /* saved signal handlers */
+#endif
+
+static sigset_t jvmsigs; /* Signals used by jvm. */
+
+#ifdef MACOSX
+static __thread bool reentry = false; /* prevent reentry deadlock (per-thread) */
+#endif
+
+/* Used to synchronize the installation of signal handlers. */
+static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+static pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
+static pthread_t tid = 0;
+
+typedef void (*sa_handler_t)(int);
+typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
+typedef sa_handler_t (*signal_function_t)(int, sa_handler_t);
+typedef int (*sigaction_t)(int, const struct sigaction *, struct sigaction *);
+
+static signal_function_t os_signal = 0; /* os's version of signal()/sigset() */
+static sigaction_t os_sigaction = 0; /* os's version of sigaction() */
+
+static bool jvm_signal_installing = false;
+static bool jvm_signal_installed = false;
+
+
+/* assume called within signal_lock */
+static void allocate_sact() {
+#ifdef SOLARIS
+ if (sact == NULL) {
+ sact = (struct sigaction *)malloc((MAX_SIGNALS) * (size_t)sizeof(struct sigaction));
+ if (sact == NULL) {
+ printf("%s\n", "libjsig.so unable to allocate memory");
+ exit(0);
+ }
+ memset(sact, 0, (MAX_SIGNALS) * (size_t)sizeof(struct sigaction));
+ }
+#endif
+}
+
+static void signal_lock() {
+ pthread_mutex_lock(&mutex);
+ /* When the jvm is installing its set of signal handlers, threads
+ * other than the jvm thread should wait. */
+ if (jvm_signal_installing) {
+ if (tid != pthread_self()) {
+ pthread_cond_wait(&cond, &mutex);
+ }
+ }
+}
+
+static void signal_unlock() {
+ pthread_mutex_unlock(&mutex);
+}
+
+static sa_handler_t call_os_signal(int sig, sa_handler_t disp,
+ bool is_sigset) {
+ sa_handler_t res;
+
+ if (os_signal == NULL) {
+ if (!is_sigset) {
+ os_signal = (signal_function_t)dlsym(RTLD_NEXT, "signal");
+ } else {
+ os_signal = (signal_function_t)dlsym(RTLD_NEXT, "sigset");
+ }
+ if (os_signal == NULL) {
+ printf("%s\n", dlerror());
+ exit(0);
+ }
+ }
+
+#ifdef MACOSX
+ /* On macosx, the OS implementation of signal calls sigaction.
+ * Make sure we do not deadlock with ourself. (See JDK-8072147). */
+ reentry = true;
+#endif
+
+ res = (*os_signal)(sig, disp);
+
+#ifdef MACOSX
+ reentry = false;
+#endif
+
+ return res;
+}
+
+static void save_signal_handler(int sig, sa_handler_t disp, bool is_sigset) {
+ sigset_t set;
+
+ sact[sig].sa_handler = disp;
+ sigemptyset(&set);
+ sact[sig].sa_mask = set;
+ if (!is_sigset) {
+#ifdef SOLARIS
+ sact[sig].sa_flags = SA_NODEFER;
+ if (sig != SIGILL && sig != SIGTRAP && sig != SIGPWR) {
+ sact[sig].sa_flags |= SA_RESETHAND;
+ }
+#else
+ sact[sig].sa_flags = 0;
+#endif
+ } else {
+ sact[sig].sa_flags = 0;
+ }
+}
+
+static sa_handler_t set_signal(int sig, sa_handler_t disp, bool is_sigset) {
+ sa_handler_t oldhandler;
+ bool sigused;
+ bool sigblocked;
+
+ signal_lock();
+ allocate_sact();
+
+ sigused = sigismember(&jvmsigs, sig);
+ if (jvm_signal_installed && sigused) {
+ /* jvm has installed its signal handler for this signal. */
+ /* Save the handler. Don't really install it. */
+ if (is_sigset) {
+ sigblocked = sigismember(&(sact[sig].sa_mask), sig);
+ }
+ oldhandler = sact[sig].sa_handler;
+ save_signal_handler(sig, disp, is_sigset);
+
+#ifdef SOLARIS
+ if (is_sigset && sigblocked) {
+ /* We won't honor the SIG_HOLD request to change the signal mask */
+ oldhandler = SIG_HOLD;
+ }
+#endif
+
+ signal_unlock();
+ return oldhandler;
+ } else if (jvm_signal_installing) {
+ /* jvm is installing its signal handlers. Install the new
+ * handlers and save the old ones. jvm uses sigaction().
+ * Leave the piece here just in case. */
+ oldhandler = call_os_signal(sig, disp, is_sigset);
+ save_signal_handler(sig, oldhandler, is_sigset);
+
+ /* Record the signals used by jvm */
+ sigaddset(&jvmsigs, sig);
+
+ signal_unlock();
+ return oldhandler;
+ } else {
+ /* jvm has no relation with this signal (yet). Install the
+ * the handler. */
+ oldhandler = call_os_signal(sig, disp, is_sigset);
+
+ signal_unlock();
+ return oldhandler;
+ }
+}
+
+sa_handler_t signal(int sig, sa_handler_t disp) {
+ if (sig < 0 || sig >= MAX_SIGNALS) {
+ errno = EINVAL;
+ return SIG_ERR;
+ }
+
+ return set_signal(sig, disp, false);
+}
+
+sa_handler_t sigset(int sig, sa_handler_t disp) {
+#ifdef _ALLBSD_SOURCE
+ printf("sigset() is not supported by BSD");
+ exit(0);
+#else
+ if (sig < 0 || sig >= MAX_SIGNALS) {
+ errno = EINVAL;
+ return (sa_handler_t)-1;
+ }
+
+ return set_signal(sig, disp, true);
+#endif
+}
+
+static int call_os_sigaction(int sig, const struct sigaction *act,
+ struct sigaction *oact) {
+ if (os_sigaction == NULL) {
+ os_sigaction = (sigaction_t)dlsym(RTLD_NEXT, "sigaction");
+ if (os_sigaction == NULL) {
+ printf("%s\n", dlerror());
+ exit(0);
+ }
+ }
+ return (*os_sigaction)(sig, act, oact);
+}
+
+int sigaction(int sig, const struct sigaction *act, struct sigaction *oact) {
+ int res;
+ bool sigused;
+ struct sigaction oldAct;
+
+ if (sig < 0 || sig >= MAX_SIGNALS) {
+ errno = EINVAL;
+ return -1;
+ }
+
+#ifdef MACOSX
+ if (reentry) {
+ return call_os_sigaction(sig, act, oact);
+ }
+#endif
+
+ signal_lock();
+
+ allocate_sact();
+ sigused = sigismember(&jvmsigs, sig);
+ if (jvm_signal_installed && sigused) {
+ /* jvm has installed its signal handler for this signal. */
+ /* Save the handler. Don't really install it. */
+ if (oact != NULL) {
+ *oact = sact[sig];
+ }
+ if (act != NULL) {
+ sact[sig] = *act;
+ }
+
+ signal_unlock();
+ return 0;
+ } else if (jvm_signal_installing) {
+ /* jvm is installing its signal handlers. Install the new
+ * handlers and save the old ones. */
+ res = call_os_sigaction(sig, act, &oldAct);
+ sact[sig] = oldAct;
+ if (oact != NULL) {
+ *oact = oldAct;
+ }
+
+ /* Record the signals used by jvm. */
+ sigaddset(&jvmsigs, sig);
+
+ signal_unlock();
+ return res;
+ } else {
+ /* jvm has no relation with this signal (yet). Install the
+ * the handler. */
+ res = call_os_sigaction(sig, act, oact);
+
+ signal_unlock();
+ return res;
+ }
+}
+
+/* The three functions for the jvm to call into. */
+void JVM_begin_signal_setting() {
+ signal_lock();
+ sigemptyset(&jvmsigs);
+ jvm_signal_installing = true;
+ tid = pthread_self();
+ signal_unlock();
+}
+
+void JVM_end_signal_setting() {
+ signal_lock();
+ jvm_signal_installed = true;
+ jvm_signal_installing = false;
+ pthread_cond_broadcast(&cond);
+ signal_unlock();
+}
+
+struct sigaction *JVM_get_signal_action(int sig) {
+ allocate_sact();
+ /* Does race condition make sense here? */
+ if (sigismember(&jvmsigs, sig)) {
+ return &sact[sig];
+ }
+ return NULL;
+}