Whipped up some native code to allow signals to be caught and handled from

within Java (on Linux anyway). We dig it the most baby!


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@2360 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/util/keybd/i686-Linux/Makefile

@@ -1,5 +1,5 @@
 #
-# $Id: Makefile,v 1.4 2003/02/18 23:06:54 ray Exp $
+# $Id: Makefile,v 1.5 2003/03/31 02:10:04 mdb Exp $
 
 #
 # Executable definitions
@@ -30,10 +30,12 @@ INSTALL_TARGET=${INSTALL_PATH}/${TARGET}
 all: ${INSTALL_TARGET}
 
 ${INSTALL_TARGET}: com_threerings_util_keybd_Keyboard.c
-	${CC} ${INCLUDES} -c com_threerings_util_keybd_Keyboard.c \
+	@echo Compiling Keyboard.c
+	@${CC} ${INCLUDES} -c com_threerings_util_keybd_Keyboard.c \
 	    -o com_threerings_util_keybd_Keyboard.o
-	${MKDIR} -p ${INSTALL_PATH}
+	@echo Creating libkeybd.so
-	${CC} -o ${INSTALL_TARGET} com_threerings_util_keybd_Keyboard.o \
+	@${MKDIR} -p ${INSTALL_PATH}
+	@${CC} -o ${INSTALL_TARGET} com_threerings_util_keybd_Keyboard.o \
 	    ${LIBRARIES} ${LIBRARIES_PATH} -shared
 
 clean:

src/java/com/threerings/util/signal/SignalManager.java

@@ -0,0 +1,261 @@
+//
+// $Id: SignalManager.java,v 1.1 2003/03/31 02:10:04 mdb Exp $
+
+package com.threerings.util.signal;
+
+import com.samskivert.util.HashIntMap;
+import com.samskivert.util.ObserverList;
+import com.threerings.util.Log;
+
+/**
+ * Uses native code to catch Unix signals and invoke callbacks on a
+ * separate signal handler thread. If the native library cannot be loaded,
+ * signal handlers will be allowed to be registered but will never be
+ * called.
+ */
+public class SignalManager
+{
+    /* Hangup (POSIX). */
+    public static final int SIGHUP = 1;
+
+    /* Interrupt (ANSI). */
+    public static final int SIGINT = 2;
+
+    /* Quit (POSIX). */
+    public static final int SIGQUIT = 3;
+
+    /* Illegal instruction (ANSI). */
+    public static final int SIGILL = 4;
+
+    /* Trace trap (POSIX). */
+    public static final int SIGTRAP = 5;
+
+    /* Abort (ANSI). */
+    public static final int SIGABRT = 6;
+
+    /* IOT trap (4.2 BSD). */
+    public static final int SIGIOT = 6;
+
+    /* BUS error (4.2 BSD). */
+    public static final int SIGBUS = 7;
+
+    /* Floating-point exception (ANSI). */
+    public static final int SIGFPE = 8;
+
+    /* Kill, unblockable (POSIX). */
+    public static final int SIGKILL = 9;
+
+    /* User-defined signal 1 (POSIX). */
+    public static final int SIGUSR1 = 10;
+
+    /* Segmentation violation (ANSI). */
+    public static final int SIGSEGV = 11;
+
+    /* User-defined signal 2 (POSIX). */
+    public static final int SIGUSR2 = 12;
+
+    /* Broken pipe (POSIX). */
+    public static final int SIGPIPE = 13;
+
+    /* Alarm clock (POSIX). */
+    public static final int SIGALRM = 14;
+
+    /* Termination (ANSI). */
+    public static final int SIGTERM = 15;
+
+    /* Stack fault. */
+    public static final int SIGSTKFLT = 16;
+
+    /* Child status has changed (POSIX). */
+    public static final int SIGCHLD = 17;
+
+    /* Continue (POSIX). */
+    public static final int SIGCONT = 18;
+
+    /* Stop, unblockable (POSIX). */
+    public static final int SIGSTOP = 19;
+
+    /* Keyboard stop (POSIX). */
+    public static final int SIGTSTP = 20;
+
+    /* Background read from tty (POSIX). */
+    public static final int SIGTTIN = 21;
+
+    /* Background write to tty (POSIX). */
+    public static final int SIGTTOU = 22;
+
+    /* Urgent condition on socket (4.2 BSD). */
+    public static final int SIGURG = 23;
+
+    /* CPU limit exceeded (4.2 BSD). */
+    public static final int SIGXCPU = 24;
+
+    /* File size limit exceeded (4.2 BSD). */
+    public static final int SIGXFSZ = 25;
+
+    /* Virtual alarm clock (4.2 BSD). */
+    public static final int SIGVTALRM = 26;
+
+    /* Profiling alarm clock (4.2 BSD). */
+    public static final int SIGPROF = 27;
+
+    /* Window size change (4.3 BSD, Sun). */
+    public static final int SIGWINCH = 28;
+
+    /* I/O now possible (4.2 BSD). */
+    public static final int SIGIO = 29;
+
+    /* Pollable event occurred (System V). */
+    public static final int SIGPOLL = SIGIO;
+
+    /* Power failure restart (System V). */
+    public static final int SIGPWR = 30;
+
+     /* Bad system call. */
+    public static final int SIGSYS = 31;
+
+    /** Used to dispatch signal notifications. */
+    public static interface SignalHandler
+    {
+        /**
+         * Called when the specified signal is received.
+         *
+         * @return true if the signal handler should remain registered,
+         * false if it should be removed.
+         */
+        public boolean signalReceived (int signal);
+    }
+
+    /**
+     * Returns true if signal dispatching services are available, false if
+     * we could not load our native library.
+     */
+    public boolean servicesAvailable ()
+    {
+        return _haveLibrary;
+    }
+
+    /**
+     * Registers a signal handler for the specified signal.
+     */
+    public synchronized static void registerSignalHandler (
+        int signal, SignalHandler handler)
+    {
+        ObserverList list =  (ObserverList)_handlers.get(signal);
+        if (list == null) {
+            _handlers.put(signal, list = new ObserverList(
+                              ObserverList.SAFE_IN_ORDER_NOTIFY));
+            if (_haveLibrary) {
+                activateHandler(signal);
+            }
+        }
+        list.add(handler);
+
+        // make sure the signal dispatcher thread is started
+        if (_haveLibrary && _sigdis == null) {
+            _sigdis = new Thread() {
+                public void run () {
+                    Log.info("Dispatching signals...");
+                    dispatchSignals();
+                }
+            };
+            _sigdis.setDaemon(true);
+            _sigdis.start();
+        }
+    }
+
+    /**
+     * Removes the registration for the specified signal handler.
+     */
+    public synchronized static void removeSignalHandler (
+        int signal, SignalHandler handler)
+    {
+        ObserverList list = (ObserverList)_handlers.get(signal);
+        if (list == null || !list.contains(handler)) {
+            Log.warning("Requested to remove non-registered handler " +
+                        "[signal=" + signal + ", handler=" + handler + "].");
+            return;
+        }
+        list.remove(handler);
+        checkEmpty(signal);
+    }
+
+    /**
+     * Called by native code when a signal is received.
+     */
+    protected synchronized static void signalReceived (final int signal)
+    {
+        // this is hack, but we seem to get a call to our signal handler
+        // for each thread if the user presses ctrl-c in the terminal, so
+        // we "collapse" those into one call back
+        long now = System.currentTimeMillis();
+        if (signal == SIGINT) {
+            if (_lastINTed == now) {
+                return;
+            } else {
+                _lastINTed = now;
+            }
+        }
+        ObserverList list = (ObserverList)_handlers.get(signal);
+        if (list != null) {
+            list.apply(new ObserverList.ObserverOp() {
+                public boolean apply (Object obs) {
+                    return ((SignalHandler)obs).signalReceived(signal);
+                }
+            });
+        }
+        checkEmpty(signal);
+    }
+
+    /**
+     * Called when a signal handler is removed.
+     */
+    protected static void checkEmpty (int signal)
+    {
+        ObserverList list = (ObserverList)_handlers.get(signal);
+        if (list != null && list.size() == 0) {
+            _handlers.remove(signal);
+            if (_haveLibrary) {
+                deactivateHandler(signal);
+            }
+        }
+    }
+
+    /**
+     * Activates the signal handler for the specified signal.
+     */
+    protected static native void activateHandler (int signal);
+
+    /**
+     * Deactivates the signal handler for the specified signal.
+     */
+    protected static native void deactivateHandler (int signal);
+
+    /**
+     * Consigns a Java thread to the task of dispatching signal handler
+     * callbacks.
+     */
+    protected static native void dispatchSignals ();
+
+    /** A mapping from signal number to a list of handlers. */
+    protected static HashIntMap _handlers = new HashIntMap();
+
+    /** Our signal dispatcher thread. */
+    protected static Thread _sigdis;
+
+    /** Set to true if we successfully load our native library. */
+    protected static boolean _haveLibrary;
+
+    /** Used to collapse bogus multiple delivery of SIGINT when the user
+     * pressed ctrl-c in the console. */
+    protected static long _lastINTed = 0L;
+
+    static {
+        try {
+            System.loadLibrary("signal");
+            _haveLibrary = true;
+        } catch (Throwable t) {
+            Log.info("Could not load libsignal.so; signal handling disabled.");
+        }
+    }
+}

src/java/com/threerings/util/signal/com_threerings_util_signal_SignalManager.h

@@ -0,0 +1,104 @@
+/* DO NOT EDIT THIS FILE - it is machine generated */
+#include <jni.h>
+/* Header for class com_threerings_util_signal_SignalManager */
+
+#ifndef _Included_com_threerings_util_signal_SignalManager
+#define _Included_com_threerings_util_signal_SignalManager
+#ifdef __cplusplus
+extern "C" {
+#endif
+#undef com_threerings_util_signal_SignalManager_SIGHUP
+#define com_threerings_util_signal_SignalManager_SIGHUP 1L
+#undef com_threerings_util_signal_SignalManager_SIGINT
+#define com_threerings_util_signal_SignalManager_SIGINT 2L
+#undef com_threerings_util_signal_SignalManager_SIGQUIT
+#define com_threerings_util_signal_SignalManager_SIGQUIT 3L
+#undef com_threerings_util_signal_SignalManager_SIGILL
+#define com_threerings_util_signal_SignalManager_SIGILL 4L
+#undef com_threerings_util_signal_SignalManager_SIGTRAP
+#define com_threerings_util_signal_SignalManager_SIGTRAP 5L
+#undef com_threerings_util_signal_SignalManager_SIGABRT
+#define com_threerings_util_signal_SignalManager_SIGABRT 6L
+#undef com_threerings_util_signal_SignalManager_SIGIOT
+#define com_threerings_util_signal_SignalManager_SIGIOT 6L
+#undef com_threerings_util_signal_SignalManager_SIGBUS
+#define com_threerings_util_signal_SignalManager_SIGBUS 7L
+#undef com_threerings_util_signal_SignalManager_SIGFPE
+#define com_threerings_util_signal_SignalManager_SIGFPE 8L
+#undef com_threerings_util_signal_SignalManager_SIGKILL
+#define com_threerings_util_signal_SignalManager_SIGKILL 9L
+#undef com_threerings_util_signal_SignalManager_SIGUSR1
+#define com_threerings_util_signal_SignalManager_SIGUSR1 10L
+#undef com_threerings_util_signal_SignalManager_SIGSEGV
+#define com_threerings_util_signal_SignalManager_SIGSEGV 11L
+#undef com_threerings_util_signal_SignalManager_SIGUSR2
+#define com_threerings_util_signal_SignalManager_SIGUSR2 12L
+#undef com_threerings_util_signal_SignalManager_SIGPIPE
+#define com_threerings_util_signal_SignalManager_SIGPIPE 13L
+#undef com_threerings_util_signal_SignalManager_SIGALRM
+#define com_threerings_util_signal_SignalManager_SIGALRM 14L
+#undef com_threerings_util_signal_SignalManager_SIGTERM
+#define com_threerings_util_signal_SignalManager_SIGTERM 15L
+#undef com_threerings_util_signal_SignalManager_SIGSTKFLT
+#define com_threerings_util_signal_SignalManager_SIGSTKFLT 16L
+#undef com_threerings_util_signal_SignalManager_SIGCHLD
+#define com_threerings_util_signal_SignalManager_SIGCHLD 17L
+#undef com_threerings_util_signal_SignalManager_SIGCONT
+#define com_threerings_util_signal_SignalManager_SIGCONT 18L
+#undef com_threerings_util_signal_SignalManager_SIGSTOP
+#define com_threerings_util_signal_SignalManager_SIGSTOP 19L
+#undef com_threerings_util_signal_SignalManager_SIGTSTP
+#define com_threerings_util_signal_SignalManager_SIGTSTP 20L
+#undef com_threerings_util_signal_SignalManager_SIGTTIN
+#define com_threerings_util_signal_SignalManager_SIGTTIN 21L
+#undef com_threerings_util_signal_SignalManager_SIGTTOU
+#define com_threerings_util_signal_SignalManager_SIGTTOU 22L
+#undef com_threerings_util_signal_SignalManager_SIGURG
+#define com_threerings_util_signal_SignalManager_SIGURG 23L
+#undef com_threerings_util_signal_SignalManager_SIGXCPU
+#define com_threerings_util_signal_SignalManager_SIGXCPU 24L
+#undef com_threerings_util_signal_SignalManager_SIGXFSZ
+#define com_threerings_util_signal_SignalManager_SIGXFSZ 25L
+#undef com_threerings_util_signal_SignalManager_SIGVTALRM
+#define com_threerings_util_signal_SignalManager_SIGVTALRM 26L
+#undef com_threerings_util_signal_SignalManager_SIGPROF
+#define com_threerings_util_signal_SignalManager_SIGPROF 27L
+#undef com_threerings_util_signal_SignalManager_SIGWINCH
+#define com_threerings_util_signal_SignalManager_SIGWINCH 28L
+#undef com_threerings_util_signal_SignalManager_SIGIO
+#define com_threerings_util_signal_SignalManager_SIGIO 29L
+#undef com_threerings_util_signal_SignalManager_SIGPOLL
+#define com_threerings_util_signal_SignalManager_SIGPOLL 29L
+#undef com_threerings_util_signal_SignalManager_SIGPWR
+#define com_threerings_util_signal_SignalManager_SIGPWR 30L
+#undef com_threerings_util_signal_SignalManager_SIGSYS
+#define com_threerings_util_signal_SignalManager_SIGSYS 31L
+/* Inaccessible static: _handlers */
+/*
+ * Class:     com_threerings_util_signal_SignalManager
+ * Method:    activateHandler
+ * Signature: (I)V
+ */
+JNIEXPORT void JNICALL Java_com_threerings_util_signal_SignalManager_activateHandler
+  (JNIEnv *, jclass, jint);
+
+/*
+ * Class:     com_threerings_util_signal_SignalManager
+ * Method:    deactivateHandler
+ * Signature: (I)V
+ */
+JNIEXPORT void JNICALL Java_com_threerings_util_signal_SignalManager_deactivateHandler
+  (JNIEnv *, jclass, jint);
+
+/*
+ * Class:     com_threerings_util_signal_SignalManager
+ * Method:    dispatchSignals
+ * Signature: ()V
+ */
+JNIEXPORT void JNICALL Java_com_threerings_util_signal_SignalManager_dispatchSignals
+  (JNIEnv *, jclass);
+
+#ifdef __cplusplus
+}
+#endif
+#endif

src/java/com/threerings/util/signal/i686-Linux/Makefile

@@ -0,0 +1,43 @@
+#
+# $Id: Makefile,v 1.1 2003/03/31 02:10:04 mdb Exp $
+
+#
+# Executable definitions
+
+CC=gcc
+RM=rm
+CP=cp
+MKDIR=mkdir
+
+#
+# Directory definitions
+
+ROOT=../../../../../../..
+LIBRARIES_PATH=
+INSTALL_PATH=${ROOT}/dist/lib/i686-Linux
+
+#
+# Parameter and file definitions
+
+INCLUDES=-I.. -I${JAVA_HOME}/include -I${JAVA_HOME}/include/linux
+LIBRARIES=
+TARGET=libsignal.so
+INSTALL_TARGET=${INSTALL_PATH}/${TARGET}
+
+#
+# Target definitions
+
+all: ${INSTALL_TARGET}
+
+${INSTALL_TARGET}: com_threerings_util_signal_SignalManager.c
+	@echo Compiling SignalManager.c
+	@${CC} ${INCLUDES} -c com_threerings_util_signal_SignalManager.c \
+	    -o com_threerings_util_signal_SignalManager.o
+	@echo Creating libsignal.so
+	@${MKDIR} -p ${INSTALL_PATH}
+	@${CC} -o ${INSTALL_TARGET} com_threerings_util_signal_SignalManager.o \
+	    ${LIBRARIES} ${LIBRARIES_PATH} -shared
+
+clean:
+	-${RM} *.o
+	-${RM} ${INSTALL_TARGET}

src/java/com/threerings/util/signal/i686-Linux/com_threerings_util_signal_SignalManager.c

@@ -0,0 +1,96 @@
+/**
+ * $Id: com_threerings_util_signal_SignalManager.c,v 1.1 2003/03/31 02:10:04 mdb Exp $
+ */
+
+#include <signal.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+
+#include <jni.h>
+#include "com_threerings_util_signal_SignalManager.h"
+
+static int writefd;
+
+typedef void (*sighandler_t)(int);
+static sighandler_t old_handlers[64];
+static sighandler_t handlers[64];
+
+static void
+signal_handler (int signo)
+{
+    write(writefd, &signo, sizeof(signo));
+    signal(SIGINT, signal_handler);
+}
+
+/**
+ * Class:     com_threerings_util_signal_SignalManager
+ * Method:    activateHandler
+ * Signature: (I)V
+ */
+JNIEXPORT void JNICALL
+Java_com_threerings_util_signal_SignalManager_activateHandler (
+    JNIEnv* env, jclass clazz, jint signo)
+{
+    old_handlers[signo] = signal(signo, signal_handler);
+    if (old_handlers[signo] == SIG_ERR) {
+        fprintf(stderr, "Error setting signal handler (%d): %s\n",
+                signo, strerror(errno));
+        old_handlers[signo] = 0;
+    } else {
+        handlers[signo] = signal_handler;
+    }
+}
+
+/**
+ * Class:     com_threerings_util_signal_SignalManager
+ * Method:    deactivateHandler
+ * Signature: (I)V
+ */
+JNIEXPORT void JNICALL
+Java_com_threerings_util_signal_SignalManager_deactivateHandler (
+    JNIEnv* env, jclass clazz, jint signo)
+{
+    if (old_handlers[signo] != 0) {
+        signal(signo, old_handlers[signo]);
+        old_handlers[signo] = 0;
+        handlers[signo] = 0;
+    }
+}
+
+/**
+ * Class:     com_threerings_util_signal_SignalManager
+ * Method:    dispatchSignals
+ * Signature: ()V
+ */
+JNIEXPORT void JNICALL
+Java_com_threerings_util_signal_SignalManager_dispatchSignals (
+    JNIEnv* env, jclass clazz)
+{
+    int filedes[2], readfd;
+    jint signo;
+    jmethodID mid = (*env)->GetStaticMethodID(
+        env, clazz, "signalReceived", "(I)V");
+
+    if (pipe(filedes) < 0) {
+        fprintf(stderr, "Failed to create signal pipe: %s\n", strerror(errno));
+        return;
+    }
+    readfd = filedes[0];
+    writefd = filedes[1];
+
+    while (1) {
+        int got = read(readfd, &signo, sizeof(int));
+        if (got < 0) {
+            fprintf(stderr, "Signal pipe read failed: %s\n", strerror(errno));
+        } else if (got == 0) {
+            fprintf(stderr, "Signal pipe read returned zero bytes.\n");
+        } else {
+            if (signo < 0 || signo >= 64 || handlers[signo] == 0) {
+                fprintf(stderr, "Received bogus signal (%d).\n", signo);
+            } else {
+                (*env)->CallStaticVoidMethod(env, clazz, mid, signo);
+            }
+        }
+    }
+}