Code Review 7110017: is_headless_jre should be updated to reflect the new,location of awt toolkit libraries

[David Holmes]

Hi Dmitry,

On 15/11/2011 10:17 PM, Dmitry Samersoff wrote:
> 1.  What is the goal of renaming xawtstr to new_xawtstr?

It isn't renamed. We added new_xawtstr to refer to the new library name, 
while keeping xawtstr to refer to the old library name - this code has 
to work for JDK 8 and JDK 7 and the library renaming is only in 8. We 
removed the (as of JDK7) unused motifstr.

> 2.  (Not to your code but as far as you touch it) "libawt_xawt" is
> longer than "libjvm" but we are copying it to static buffer without a
> boundary check - it can cause buffer overflow in some marginal case and
> clearly exploitable.
>
> I would prefer to add extra 5 bytes to libmawtpath
> ( sizeof("libawt_xawt.so") - sizeof("libjvm.so") )
>
>   char libmawtpath[MAXPATHLEN + 5];

Note that we are replacing either

client/libjvm.so  (16 chars)

or

server/libjvm.so (16 chars)

with either:

xawt/libmawt.so (15 chars)

or

libawt_xawt.so  (14 chars)

so there is no danger of overflow.

> 3. I don't see Windows changes - is it OK ?

Yes. is_headless_jre() is always false on Windows as there is no 
headless JRE there.

Thanks,
David
-----

>
>
>
> On 2011-11-15 06:05, David Holmes wrote:
>> Pinging runtime! One more Reviewer please.
>>
>> Thanks,
>> David
>>
>> On 11/11/2011 9:11 PM, David Holmes wrote:
>>> Chris,
>>>
>>> Thanks for contributing the changes. I've applied them and tested them
>>> so it is a Thumbs Up from me.
>>>
>>> We need one further Reviewer from runtime.
>>>
>>> Thanks,
>>> David
>>>
>>> On 11/11/2011 9:12 PM, Chris Hegarty wrote:
>>>>
>>>> With the changes proposed by CR 7110002: "Rename xawt/libmawt.so and
>>>> headless/libmawt.so so they can be colocated with libawt",
>>>> os::is_headless_jre() will have to be updated to look for the renamed
>>>> awt toolkit libraries. See the discussion on awt-dev for further
>>>> information:
>>>> http://mail.openjdk.java.net/pipermail/awt-dev/2011-November/002026.html
>>>>
>>>> The check for the motif toolkit can also be removed as the motif based
>>>> toolkit has been removed in JDK7.
>>>>
>>>> Since is_headless_jre is checking is for headless and short circuits
>>>> and returns false ( headed ) if it finds any headed library we can
>>>> just check for the existence of either the new or old library, without
>>>> JDK version specific code. If either exists then it is a headed
>>>> environment.
>>>>
>>>> Webrev:
>>>> http://cr.openjdk.java.net/~dholmes/7110017/webrev/
>>>>
>>>> -Chris.
>>>>
>>>> P.S. Thanks to David Holmes for helping drive this on the vm side.
>
>