[Jamvm-general] Implement JVM_FindClassFromCaller OpenJDK: 8015256: Better class accessibility

[Xerxes R. <xe...@gu...>]

The latest OpenJDK secuity update broke all alternative JVM support by
introducing a new symbol JVM_FindClassFromCaller

java -jamvm -version
java: relocation error:
/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/libjava.so: symbol
JVM_FindClassFromCaller, version SUNWprivate_1.1 not defined in file
libjvm.so with link time reference


The OpenJDK source tree revealed the following information:

8015256: Better class accessibility

Summary: Improve protection domain check in forName()

http://hg.openjdk.java.net/jdk7u/jdk7u/hotspot/rev/61d1e75e0a58
http://hg.openjdk.java.net/jdk7u/jdk7u/jdk/rev/16cd2826a58f


JVM_FindClassFromCaller appears to work quite similar to
JVM_FindClassFromClassLoader with the twist that the protection domain that
belongs to the caller class argument shall be used during the lookup of the
class.

The attached patch implements JVM_FindClassFromCaller for JamVM with this
obvious TODO:
/* XXX The caller's protection domain should be used during   the
findClassFromClassLoader but there is no specification or   unit-test in
OpenJDK documenting the desired effect */

java -jamvm -version
java version "1.7.0_65"
OpenJDK Runtime Environment (IcedTea 2.5.3) (7u71-2.5.3-0ubuntu0.14.04.1)
JamVM (build 2.0.1-devel, inline-threaded interpreter)


Cheers
Xerxes