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src/java.base/unix/native/libjsig/jsig.c

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@@ -1,7 +1,8 @@
 /*
- * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
+ * 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.

@@ -20,116 +21,180 @@
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 
-/* CopyrightVersion 1.2 */
-
 /* 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 <signal.h>
 #include <dlfcn.h>
-#include <pthread.h>
+#include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <stdint.h>
 
-#define bool int
-#define true 1
-#define false 0
-
-#define MASK(sig) ((uint64_t)1 << (sig-1))  // 0 is not a signal.
-// Check whether all signals fit into jvmsigs. -1 as MASK shifts by -1.
-#if (64 < NSIG-1)
-#error "Not all signals can be encoded in jvmsigs. Adapt its type!"
+#ifdef SOLARIS
+  #include <synch.h>
+  #include <thread.h>
+#else
+  #include <pthread.h>
+#endif
+
+#if (__STDC_VERSION__ >= 199901L)
+  #include <stdbool.h>
+#else
+  #define bool int
+  #define true 1
+  #define false 0
 #endif
+
+#ifndef NSIG
+  #define NSIG SIGRTMAX
+#endif
+
 static struct sigaction sact[NSIG]; /* saved signal handlers */
-static uint64_t jvmsigs = 0; /* signals used by jvm */
+static sigset_t jvmsigs; /* Signals used by jvm. */
+static __thread bool reentry = false; /* prevent reentry deadlock (per-thread) */
 
-/* used to synchronize the installation of signal handlers */
+/* Used to synchronize the installation of signal handlers. */
+#ifdef SOLARIS
+static mutex_t mutex = DEFAULTMUTEX;
+static cond_t cond = DEFAULTCV;
+static thread_t tid = 0;
+#else
 static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
 static pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
 static pthread_t tid = 0;
+#endif
 
 typedef void (*sa_handler_t)(int);
 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
-typedef sa_handler_t (*signal_t)(int, sa_handler_t);
+typedef sa_handler_t (*signal_function_t)(int, sa_handler_t);
 typedef int (*sigaction_t)(int, const struct sigaction *, struct sigaction *);
 
-static signal_t os_signal = 0; /* os's version of signal()/sigset() */
+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;
 
 static void signal_lock() {
+#ifdef SOLARIS
+  mutex_lock(&mutex);
+#else
   pthread_mutex_lock(&mutex);
+#endif
   /* When the jvm is installing its set of signal handlers, threads
-   * other than the jvm thread should wait */
+   * other than the jvm thread should wait. */
   if (jvm_signal_installing) {
+#ifdef SOLARIS
+    if (tid != thr_self()) {
+      cond_wait(&cond, &mutex);
+    }
+#else
     if (tid != pthread_self()) {
       pthread_cond_wait(&cond, &mutex);
     }
+#endif
   }
 }
 
 static void signal_unlock() {
+#ifdef SOLARIS
+  mutex_unlock(&mutex);
+#else
   pthread_mutex_unlock(&mutex);
+#endif
 }
 
 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_t)dlsym(RTLD_NEXT, "signal");
+#ifdef AIX
+      os_signal = signal;
+#else
+      os_signal = (signal_function_t)dlsym(RTLD_NEXT, "signal");
+#endif
     } else {
-      os_signal = (signal_t)dlsym(RTLD_NEXT, "sigset");
+#ifdef AIX
+      os_signal = sigset;
+#else
+      os_signal = (signal_function_t)dlsym(RTLD_NEXT, "sigset");
+#endif
     }
     if (os_signal == NULL) {
       printf("%s\n", dlerror());
       exit(0);
     }
   }
-  return (*os_signal)(sig, disp);
+  /* On some OSes like macosx, the OS implementation of signal calls sigaction.
+   * Make sure we do not deadlock with ourself. (See JDK-8072147). */
+  reentry = true;
+  res = (*os_signal)(sig, disp);
+  reentry = false;
+  return res;
 }
 
-static void save_signal_handler(int sig, sa_handler_t disp) {
+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();
 
-  sigused = (sig < NSIG) && ((MASK(sig) & jvmsigs) != 0);
+  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);
+    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 (sig < NSIG && jvm_signal_installing) {
+  } 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);
+    save_signal_handler(sig, oldhandler, is_sigset);
 
     /* Record the signals used by jvm */
-    jvmsigs |= MASK(sig);
+    sigaddset(&jvmsigs, sig);
 
     signal_unlock();
     return oldhandler;
   } else {
     /* jvm has no relation with this signal (yet). Install the

@@ -144,17 +209,26 @@
 sa_handler_t signal(int sig, sa_handler_t disp) {
   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
   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) {
+#ifdef AIX
+    os_sigaction = sigaction;
+#else
     os_sigaction = (sigaction_t)dlsym(RTLD_NEXT, "sigaction");
+#endif
     if (os_sigaction == NULL) {
       printf("%s\n", dlerror());
       exit(0);
     }
   }

@@ -164,13 +238,17 @@
 int sigaction(int sig, const struct sigaction *act, struct sigaction *oact) {
   int res;
   bool sigused;
   struct sigaction oldAct;
 
+  if (reentry) {
+    return call_os_sigaction(sig, act, oact);
+  }
+
   signal_lock();
 
-  sigused = (sig < NSIG) && ((MASK(sig) & jvmsigs) != 0);
+  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];

@@ -179,21 +257,21 @@
       sact[sig] = *act;
     }
 
     signal_unlock();
     return 0;
-  } else if (sig < NSIG && jvm_signal_installing) {
+  } 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 */
-    jvmsigs |= MASK(sig);
+    /* Record the signals used by jvm. */
+    sigaddset(&jvmsigs, sig);
 
     signal_unlock();
     return res;
   } else {
     /* jvm has no relation with this signal (yet). Install the

@@ -203,28 +281,37 @@
     signal_unlock();
     return res;
   }
 }
 
-/* The three functions for the jvm to call into */
+/* The three functions for the jvm to call into. */
 void JVM_begin_signal_setting() {
   signal_lock();
+  sigemptyset(&jvmsigs);
   jvm_signal_installing = true;
+#ifdef SOLARIS
+  tid = thr_self();
+#else
   tid = pthread_self();
+#endif
   signal_unlock();
 }
 
 void JVM_end_signal_setting() {
   signal_lock();
   jvm_signal_installed = true;
   jvm_signal_installing = false;
+#ifdef SOLARIS
+  cond_broadcast(&cond);
+#else
   pthread_cond_broadcast(&cond);
+#endif
   signal_unlock();
 }
 
 struct sigaction *JVM_get_signal_action(int sig) {
   /* Does race condition make sense here? */
-  if ((MASK(sig) & jvmsigs) != 0) {
+  if (sigismember(&jvmsigs, sig)) {
     return &sact[sig];
   }
   return NULL;
 }
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