Name: diC59631 Date: 09/04/98


Background:
----------

At Oracle, we have a product which invokes the appletviewer from a C program, with valid HTML file, which in-turn invokes an Applet.

The C program creates a new thread. This thread loads the java library libjava.so (javai.dll on Win32), locates the function java_main. It then executes a call to this function with the following arguments (name testjni.html chosen for simplicity).

'sun.applet.AppletViewer testjni.html'

testjni.html is a generated HTML file which has the information to invoke a custom applet. This applet communicates with the C program using JNI to run the application.


This works fine in win32 environment.


Problem:
-------

 On Solaris, this does not work. The appletviewer exits with a segmentation violation. However, if the java library is linked with the C program it invokes the appletviewer properly and the client applet runs as part of the program.

 Our requirement is to load the JDK dynamically.


Note:
----

  1. JAVAHOME environment variable is set to the local JDK installation, which in my case is '/local/java/solaris/jdk/1_1_4'

  2. I am using green-threads by default

  3. I am not using threads in this example for simplicity

  4. Please forward any work around and alternatives directly to me. Thanks



Information to repeat the bug:
-----------------------------

 I have a created a simple test case with a C program (test.c), Java file (TestJNI.java) and HTML file (testjni.html). These are attached with this bug description.

 Steps to produce the bug:

  1. compile the C file with the following command line

   solaris> cc test.c -DLOAD_DYNAMIC -ldl -o testjni

  2. copy the TestJNI.java file in to the same directory

   solaris> javac TestJNI.java

  3. copy the jnicall.html to the same directory

  4. Execute the C programe

    solaris> testjni

  Result: notice that appletviewer exits with a core dump.


 Files: Total 3
 --------------

 1. test.c
 2. TestJNI.java
 3. jnicall.html

-------------------test.c---------------------------------
 #include <stdio.h>
#include <dlfcn.h>

#define LIBPATH ((const char*)"LD_LIBRARY_PATH")
#define JAVALIB ((const char*)"libjava.so")
#define NUMARGS (3)

int main(int argc, char **argv)
{
 int ldpathlen;
 void *handle;
 void (*javamain)(int , char **);
 char *libpath, *javahome, *ldpath;
 char **jargv;

 printf("Fetching %s...\n", LIBPATH);
 libpath = getenv(LIBPATH);
 printf("%s : %s\n", LIBPATH, libpath);

 printf("Fetching JAVAHOME...\n");
 javahome = getenv("JAVAHOME");
 printf("JAVAHOME : %s\n", javahome);

 ldpathlen = strlen(LIBPATH) + strlen(javahome) + 3 +
             strlen("/lib/sparc/green_threads/") + strlen(":") + strlen(libpath);
 ldpath = (char *)malloc(ldpathlen);
 sprintf(ldpath, "%s=%s:%s/lib/sparc/green_threads", LIBPATH, libpath, javahome);
 if ( putenv(ldpath) != 0 )
 {
  printf("Error in setting %s\n", LIBPATH);
 }
 printf("Setting %s : %s\n", LIBPATH, getenv(LIBPATH));

#ifdef LOAD_DYNAMIC
 printf("Loading the %s...\n", JAVALIB);
 handle = dlopen("libjava.so", RTLD_NOW);
 if ( handle )
 {
  printf("Loaded the libjava.so...\n");
 }
 else
 {
  printf("Error in loading libjava.so...\n");
  printf("Error : %s\n", dlerror());
  free(ldpath);
  return -1;
 }

 printf("Finding the java_main...\n");
 javamain = dlsym( handle, "java_main");
 if ( javamain )
 {
  printf("Found the java_main...\n");
 }
 else
 {
  printf("Error in finding java_main...\n");
  free(ldpath);
  dlclose(handle);
  return -1;
 }
#endif

 printf("Calling java_main...\n");
 jargv = (char **) malloc( sizeof(char *) * NUMARGS);
 jargv[0] = (char *)malloc( strlen("java") + 1);
 strcpy( jargv[0], "java");
 jargv[1] = (char *)malloc( strlen("sun.applet.AppletViewer") + 1);
 strcpy( jargv[1], "sun.applet.AppletViewer");
 jargv[2] = (char *)malloc( strlen("jnicall.html") + 1);
 strcpy( jargv[2], "jnicall.html");

#ifdef LOAD_DYNAMIC
 (*javamain)(NUMARGS, jargv);
#endif

#ifndef LOAD_DYNAMIC
 java_main(NUMARGS, jargv);
#endif

 printf("Returned from java_main...\n");

#ifdef LOAD_DYNAMIC
 free(ldpath);
 dlclose(handle);
#endif
}
 --------------------------------------------------------

 -------------------TestJNI.java---------------------------
import java.applet.Applet;
import java.awt.*;

public class TestJNI extends Applet
{
 public void init()
 {
    System.out.println("Init in the applet");
 }

 public void paint(Graphics g)
 {
   g.drawString("Hello world", 20, 20);
 }
}
 ------------------------------------------------------

 --------------------jnicall.html---------------------------
<applet code=TestJNI width = 200 height = 200>
</applet>
 -----------------------------------------------------------

Error message:
SIGSEGV 11* segmentation violation
    si_signo [11]: SIGSEGV 11* segmentation violation
    si_errno [0]: Error 0
    si_code [1]: SEGV_MAPERR [addr: 0x0]
 
        stackbase=EFFF9858, stackpointer=EFFF9598
 
Full thread dump:
    "Finalizer thread" (TID:0xee300220, sys_thread_t:0xef3a0de0, state:R) prio=1
    "Async Garbage Collector" (TID:0xee3001d8, sys_thread_t:0xef3d0de0, state:R)
 prio=1
    "Idle thread" (TID:0xee300190, sys_thread_t:0xef400de0, state:R) prio=0
    "Clock" (TID:0xee3000d0, sys_thread_t:0xef430de0, state:CW) prio=12
    "main" (TID:0xee3000a8, sys_thread_t:0x379f0, state:R) prio=5 *current threa
d*
        java.io.FileInputStream.<init>(FileInputStream.java)
        java.io.FileInputStream.<init>(FileInputStream.java)
        sun.applet.AppletViewer.init(AppletViewer.java:785)
        sun.applet.AppletViewer.mainInit(AppletViewer.java:1026)
        sun.applet.AppletViewer.main(AppletViewer.java:1039)
Monitor Cache Dump:
Registered Monitor Dump:
    Thread queue lock: <unowned>
    Name and type hash table lock: <unowned>
    String intern lock: <unowned>
    JNI pinning lock: <unowned>
    JNI global reference lock: <unowned>
    BinClass lock: <unowned>
    Class loading lock: <unowned>
    Java stack lock: <unowned>
    Code rewrite lock: <unowned>
    Heap lock: <unowned>
    Has finalization queue lock: <unowned>
    Finalize me queue lock: <unowned>
    Monitor IO lock: owner "main" (0x379f0, 1 entry)
    Child death monitor: <unowned>
    Event monitor: <unowned>
    I/O monitor: <unowned>
    Alarm monitor: <unowned>
        Waiting to be notified:
            "Clock"
    Sbrk lock: <unowned>
    Monitor cache expansion lock: <unowned>
    Monitor registry: owner "main" (0x379f0, 1 entry)
Thread Alarm Q:
Abort (core dumped)
(Review ID: 38061)
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