Re: [Sablevm-developer] native libs

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I was able to fix it.  I was confused for quite some time by a pointer
getting "magically" the value NULL.

From my understanding there is a bootstrap class loader and
"application" class loader(s).  The native library list in the applicatio=
n
class loader is initially NULL.  The code in
java_lang_Runtime_nativeLoad does not check if the list is initially
NULL.  The bootstrap class loader library happened not to be initially
null since is
it is initialized early with sablevm itself elsewhere.

I will clean up my code and send a patch via the bug tack system.

David

On Mon, Jan 20, 2003 at 04:21:01PM -0500, Prof. Etienne M. Gagnon wrote:
> OK.  I'm back!  :-)
>=20
> I'll look at this tomorrow.  You're on Debian/x86, right?
>=20
> Etienne
>=20
> David Paul BELANGER wrote:
> >Hi,
> >
> >I'm getting a segmentation fault when trying to load a native library.
> >The system native library (libjava-lang, libjava-io) get properly load=
ed
> >but when it comes to mine, it seems that the pointer passed to the
> >memory allocator is null.  My library seems to get properly loaded (th=
e
> >handle is non-null).
> >
> >I have included some gdb output and a simple Hello program that cause
> >the error.
> >
> >Thanks,
> >David
> >
> >
> >---
> >
> >David B=E9langer
> >Graduate Student
> >School of Computer Science
> >McGill University
> >Office: MC226
> >
> >Web page:   http://www.cs.mcgill.ca/~dbelan2/
> >Public key: http://www.cs.mcgill.ca/~dbelan2/public_key.txt
> >
> >
> >
> >----------------------------------------------------------------------=
--
> >
> >Program received signal SIGSEGV, Segmentation fault.
> >[Switching to Thread 1024 (LWP 10068)]
> >0x40029cbe in _svmf_cl_alloc (env=3D0x804d548, class_loader_info=3D0x8=
0636b8,=20
> >    size=3D12, ptr=3D0x0) at class_loader_memory_manager.c:139
> >139     class_loader_memory_manager.c: No such file or directory.
> >        in class_loader_memory_manager.c
> >(gdb) backtrace
> >#0  0x40029cbe in _svmf_cl_alloc (env=3D0x804d548,=20
> >class_loader_info=3D0x80636b8, size=3D12, ptr=3D0x0) at=20
> >    class_loader_memory_manager.c:139
> >#1  0x40029dd4 in _svmf_cl_zalloc (env=3D0x804d548,=20
> >class_loader_info=3D0x80636b8, size=3D12, ptr=3D0x0) at=20
> >    class_loader_memory_manager.c:181
> >#2  0x4002aab2 in _svmh_cl_zalloc_native_library (env=3D0x804d548,=20
> >    class_loader_info=3D0x80636b8, ptr=3D0x0) at cl_alloc.c:585
> >#3  0x400890ea in Java_java_lang_Runtime_nativeLoad (_env=3D0x804d548,=
=20
> >    this=3D0x8060028, _filename=3D0x8060610) at java_lang_Runtime.c:24=
6
> >#4  0x400df6ff in ffi_call_SYSV () from /usr/lib/libffi.so.2
> >#5  0x400df41a in ffi_call () from /usr/lib/libffi.so.2
> >#6  0x400334f8 in _svmf_invoke_native_nonstatic (env=3D0x804d548) at=20
> >native.c:1171
> >#7  0x40071b53 in _svmf_interpreter (_env=3D0x804d548)
> >    at instructions_switch.c:9839
> >#8  0x40027270 in _svmh_invoke_specific_static_clinit (env=3D0x804d548=
,=20
> >    method=3D0x4145046c) at method_invoke.c:5061
> >#9  0x40088c9e in Java_java_lang_Class_step8 (_env=3D0x804d548,=20
> >_class=3D0x805fd98, vmData=3D0x80607a0) at java_lang_Class.c:741
> >#10 0x400df6ff in ffi_call_SYSV () from /usr/lib/libffi.so.2
> >#11 0x400df41a in ffi_call () from /usr/lib/libffi.so.2
> >#12 0x40032bf8 in _svmf_invoke_native_static (env=3D0x804d548) at=20
> >native.c:834
> >#13 0x40071aa4 in _svmf_interpreter (_env=3D0x804d548)
> >    at instructions_switch.c:9791
> >#14 0x4001fbaa in _svmh_invoke_nonvirtual_jlclass_initialize=20
> >(env=3D0x804d548, this=3D0x8065b08, param_1=3D1) at method_invoke.c:35=
2
> >#15 0x4003dcaa in _svmf_class_initialization (env=3D0x804d548,=20
> >class=3D0x41450008)
> >    at initialization.c:24
> >#16 0x4008c6d5 in Java_java_lang_VirtualMachine_invokeMain=20
> >(_env=3D0x804d548, _class=3D0x805fda8, mainClass=3D0x805fdb8, args=3D0=
x805fdc8)
> >    at java_lang_VirtualMachine.c:47
> >#17 0x400df6ff in ffi_call_SYSV () from /usr/lib/libffi.so.2
> >#18 0x400df41a in ffi_call () from /usr/lib/libffi.so.2
> >#19 0x40032bf8 in _svmf_invoke_native_static (env=3D0x804d548) at=20
> >native.c:834
> >#20 0x40071aa4 in _svmf_interpreter (_env=3D0x804d548)
> >    at instructions_switch.c:9791
> >#21 0x40057a60 in CallStaticVoidMethod (_env=3D0x804d548, cls=3D0x805f=
198,=20
> >    methodID=3D0x41250818) at native_interface.c:14894
> >#22 0x0804aa4d in main (argc=3D2, argv=3D0xbffff8e4) at sablevm.c:1434
> >(gdb)=20
> >
> >
> >----------------------------------------------------------------------=
--
> >
> >
> >public class Hello {
> >
> >  static {
> >    System.loadLibrary("hello");
> >  }
> >
> >  private static native void printHello();
> >
> >
> >  public static void main(String[] args) {
> >    printHello();
> >  }
> >
> >}
> >
> >
> >----------------------------------------------------------------------=
--
> >
> >#include "Hello.h"
> >
> >#include <stdio.h>
> >
> >JNIEXPORT void JNICALL Java_Hello_printHello
> >(JNIEnv *env, jclass c) {
> >  printf("Hello!\n");
> >}
> >
> >
> >
> >----------------------------------------------------------------------=
--
> >
> >/* DO NOT EDIT THIS FILE - it is machine generated */
> >#include <jni.h>
> >/* Header for class Hello */
> >
> >#ifndef _Included_Hello
> >#define _Included_Hello
> >#ifdef __cplusplus
> >extern "C" {
> >#endif
> >/*
> > * Class:     Hello
> > * Method:    printHello
> > * Signature: ()V
> > */
> >JNIEXPORT void JNICALL Java_Hello_printHello
> >  (JNIEnv *, jclass);
> >
> >#ifdef __cplusplus
> >}
> >#endif
> >#endif
> >
> >
> >----------------------------------------------------------------------=
--
> >
> >all:
> >	libtool gcc -c -g -o hello.lo -I../../../../include Hello.c
> >	libtool gcc -o libhello.la -g hello.lo -rpath `pwd`
> >	libtool install -c libhello.la `pwd`/libhello.la
>=20
> --=20
> Etienne M. Gagnon, Ph.D.             http://www.info.uqam.ca/~egagnon/
> SableVM:                                       http://www.sablevm.org/
> SableCC:                                       http://www.sablecc.org/

--=20

---

David B=E9langer
Graduate Student
School of Computer Science
McGill University
Office: MC226

Web page:   http://www.cs.mcgill.ca/~dbelan2/
Public key: http://www.cs.mcgill.ca/~dbelan2/public_key.txt