RFR: 8220095: Assertion failure when symlink (with different name) is used for lib/modules file

[Harold Seigel]

Hi Jiangli,

The change looks good.  Could you change the call to strdup() at line 
710 in classLoader.cpp to os::strdup() ?

Also, I'm not sure about  the copyright for your new test.  I'll ask 
internally if you are using the right one.

Thanks! Harold

On 3/6/2019 6:20 PM, Jiangli Zhou wrote:
> Please review the following fix for 8220095.
>
> webrev: http://cr.openjdk.java.net/~jiangli/8220095/webrev.00/
> bug: https://bugs.openjdk.java.net/browse/JDK-8220095
>
> Symbolic links may be used commonly in some cloud environments. The target
> files might have different names than the linked names. The VM crashes when
> 'lib/modules' links to a target file with a different name, for example,
> lib/modules -> lib/0.
>
> The usage of the hard-coded MODULES_IMAGE_NAME (used by
> ClassLoader::is_modules_image(const char*)) can become problematic in this
> case and leads to assertion failures and crashes in this case. The
> is_modules_image()
> checks always fail even the actual file is the runtime image because the
> canonical paths (which might not end with 'modules') are passed in for the
> check. The fix is to obtain the real name from the canonical path early
> during initialization and use that for the is_modules_image() check.
>
> Tested with submit repo testing, tier1, tier2, and hotspot runtime tests
> locally.
>
> Thanks!
> Jiangli