[Bug classpath/40769] New: A JNI memory leak in the Java_java_lang_VMSystem_getenv native method

[lineonking at gmail dot com]

The Java_java_lang_VMSystem_getenv native method may leak a memory when the
"envname" is NULL and the JVM returns a new memory for GetStringUTFChars. The
memory cell pointed by the "cname" is a JVM resource that must be deallocated
by calling ReleaseStringUTFChars.

-------------------------
JNIEXPORT jstring JNICALL
Java_java_lang_VMSystem_getenv (JNIEnv * env,
                                jclass klass __attribute__ ((__unused__)),
                                jstring jname)
{
  const char *cname;
  const char *envname;

  cname = JCL_jstring_to_cstring (env, jname);
  if (cname == NULL)
    return NULL;

  envname = getenv (cname);
  if (envname == NULL)
    return NULL;

  JCL_free_cstring (env, jname, cname);
  return (*env)->NewStringUTF (env, envname);
}
-------------------------

I propose the following patch of freeing the JVM resource as early as possible:

Index: java_lang_VMSystem.c
===================================================================
RCS file:
/sources/classpath/classpath/native/jni/java-lang/java_lang_VMSystem.c,v
retrieving revision 1.15
diff -r1.15 java_lang_VMSystem.c
151a152
>   JCL_free_cstring (env, jname, cname);
155d155
<   JCL_free_cstring (env, jname, cname);


-- 
           Summary: A JNI memory leak in the Java_java_lang_VMSystem_getenv
                    native method
           Product: classpath
           Version: 0.98
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: classpath
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: lineonking at gmail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40769