I tried to duplicate the c example for dnotify.c here: http://souptonuts.sourceforge.net/code/dnotify.c.html

The attached is what I came up with. It works... somewhat. - I get segmentation faults if I do anything other than touch or rm a file,
(opening a file with vi or 'echo foo > foo.txt' causes the fault) - I don't get modified events. - In spite of setting the flag for the calling the 3 arg callback, it still only
calls the single arg callback.

I'm running: - Ubuntu Gutsy, Linux xxxxx 2.6.24-23-generic #1 SMP Thu Nov 27 18:44:42 UTC
2008 i686 GNU/Linux - java version "1.6.0_07" - jna-3.0.7

I've tried to get a memory dump using the instructions here:
https://jna.dev.java.net/#struct_debug (the "-Djna.dump_memory=true" prop) but
I the output just show this: sigaction: DNotify$SigAction(allocated@0x81155f0 (144 bytes)) { DNotify$__sighandler_t
sa_sighandler@0=com.sun.jna.examples.linux.DNotify$1@1cd8669 DNotify$__sigaction_t
sa_sigaction@4=com.sun.jna.examples.linux.DNotify$2@337838 DNotify$__sigset_t sa_mask@8=DNotify$__sigset_t(allocated@0x8158810 (128
bytes)) { int __val[32]@0=[I@119cca4 } int sa_flags@88=4 DNotify$__sigrestorer_t
sa_restorer@8c=com.sun.jna.examples.linux.DNotify$3@ca2dce } memory dump [00000000] [00000000] [00000000] .... (just keeps repeating the zeros)

sometimes I get a core dump, that's also attached.

Any thoughts?

/* * To change this template, choose Tools | Templates * and open the template in the editor. */

package com.sun.jna.examples.linux;

import com.sun.jna.Callback; import com.sun.jna.Library; import com.sun.jna.Native; import com.sun.jna.Pointer; import com.sun.jna.Structure; import java.io.File;

/** * * @author eearle */ public class DNotify {

public static final int SA_SIGINFO = 4; public static final int O_RDONLY = 0; public static final int F_SETSIG = 10; /* Set number of signal to be sent.
*/ public static final int F_NOTIFY = 1026; /* Request notfications on a
directory. */ public static final int DN_ACCESS = 0x00000001; /* File accessed. */ public static final int DN_MODIFY = 0x00000002; /* File modified. */ public static final int DN_CREATE = 0x00000004; /* File created. */ public static final int DN_DELETE = 0x00000008; /* File removed. */ public static final int DN_RENAME = 0x00000010; /* File renamed. */ public static final int DN_ATTRIB = 0x00000020; /* File changed attibutes.
*/ public static final int DN_MULTISHOT = 0x80000000; /* Don't remove notifier.
*/

public static class __sigset_t extends Structure { private static final int SIGSET_NWORDS = 1024 / (8 * 4); // 32 bit public int[] __val = new int[SIGSET_NWORDS]; }

public interface __sighandler_t extends Callback { // void handler(int sig, siginfo_t *si, void *data) public void callback(int sig); }

public interface __sigaction_t extends Callback { // void handler(int sig, siginfo_t *si, void *data) // public void callback(int sig, Pointer si, Pointer data); public void callback(int sig, siginfo_t si, Pointer data); }

public interface __sigrestorer_t extends Callback { // void handler(int sig, siginfo_t *si, void *data) public void callback(); }

public static class SigAction extends Structure { public __sighandler_t sa_sighandler; public __sigaction_t sa_sigaction; public __sigset_t sa_mask; public int sa_flags; public __sigrestorer_t sa_restorer; }

public static class siginfo_t extends Structure { public int si_signo; // Signal number. public int si_errno; // If non-zero, an errno value associated with
this signal, as defined in <errno.h>. public int si_code; // Signal code. public int si_fd; }

public interface CLibrary extends Library { public void sigemptyset(__sigset_t set);

// SigAction(SIGRTMIN + 1, &act, NULL); public int sigaction(int sig, SigAction action, SigAction oldAction);

//open(".", O_RDONLY); public int open(String path, int mode);

// fcntl(fd, F_SETSIG, SIGRTMIN + 1); public int fcntl(int __fd, int __cmd, int sig);

// pause(); public int pause ();

public int __libc_current_sigrtmin(); }

static volatile int event_fd; static volatile int event_sig;

public static void main(String[] args) {

System.out.println("RUNNING IN: "+new File(".").getAbsolutePath());

Native.setProtected(true); if(!Native.isProtected()) { System.out.println("\nVM CRASH PROTECTION IS NOT SUPPORTED\n"); } else { System.out.println("\nVM CRASH PROTECTION ENABLED\n"); }

CLibrary INSTANCE = (CLibrary)Native.loadLibrary("c", CLibrary.class);

int SIGRTMIN = INSTANCE.__libc_current_sigrtmin();

System.out.println("SIGRTMIN: "+SIGRTMIN);

SigAction sigaction = new SigAction();

sigaction.sa_sighandler = new __sighandler_t() { public void callback(int sig) { System.out.println("SIG HANDLER CALLBACK"); event_sig = sig; } };

sigaction.sa_sigaction = new __sigaction_t() { // public void callback(int sig, Pointer si, Pointer data) { public void callback(int sig, siginfo_t si, Pointer data) { System.out.println("SIG ACTION CALLBACK"); // System.out.println("Got event on fd="+si.si_fd+" sig="+sig); event_fd = si.si_fd; event_sig = sig; } };

sigaction.sa_restorer = new __sigrestorer_t() {

public void callback() { System.out.println("SIG RESTORER CALLBACK"); } };

INSTANCE.sigemptyset(sigaction.sa_mask); sigaction.sa_flags = SA_SIGINFO;

System.out.println("sigaction:\n"+sigaction.toString());

INSTANCE.sigaction(SIGRTMIN + 1, sigaction, null); int fd = INSTANCE.open(".", O_RDONLY);

INSTANCE.fcntl(fd, F_SETSIG, SIGRTMIN + 1); //INSTANCE.fcntl(fd, F_NOTIFY,
DN_ACCESS|DN_MODIFY|DN_CREATE|DN_RENAME|DN_DELETE|DN_ATTRIB|DN_MULTISHOT); INSTANCE.fcntl(fd, F_NOTIFY, DN_MODIFY | DN_CREATE | DN_RENAME |
DN_DELETE | DN_MULTISHOT); /* we will now be notified if any of the files in "." is modified or new files are created */ while (true) { INSTANCE.pause(); System.out.println("Got event on fd="+event_fd+" sig="+event_sig); } } }