On Wed, Sep 28, 2016 at 3:03 PM, Kumar Srinivasan
<kumar.x.sriniva...@oracle.com> wrote:
>
> Hello Thomas, Volker,
>
>
> Hi Kumar,
>
>>
>> On 9/16/2016 10:34 AM, Volker Simonis wrote:
>>>
>>> Hi Christoph,
>>>
>>> I think your change is fine as a quick-fix to fix the build. But
>>> you're completely right that this should be reworked in the long term.
>>> I hate to see that we now have the third version of these routines in
>>> the OpenJDK. Unfortunately a clean solution is not trivial.
>>>
>>> libjli is not linked against libjvm because libjli is actually used to
>>> load libjvm. So we can not put the dladdr routines for AIX there. But
>>> I think we should at least consolidate the two versions which will be
>>> in the class library after your change. Initially I intentionally put
>>> porting_aix.{c,h} into jdk/aix/porting with the intent to make it
>>> available to ALL jdk native libraries.
>>>
>>> Unfortunately, with the source code reorganization due to the modular
>>> changes, the common, top-level aix repository had to go away and the
>>> code was moved to src/java.desktop/aix/native/libawt/porting_aix.c.
>>> With the reorganized, modularized source code layout and build system
>>> it is not possible to share code between modules. We somehow have to
>>> fix this although I currently don't know how. IF somebody has an idea,
>>> please let me know :)
>>
>>
>> Why doesn't AIX support a Standard C API that most other
>> *nix based OS'es support ?
>>
>
> dladdr() is not Posix, hence it should not be used in code that wants to be
> portable across Unix systems. Afaik dladdr() is a propietary Solaris API
> that was adapted by the glibc and slowly spread over to some other Unices,
> but by no means all of them.
>
> dladdr makes a number of assumptions about the architecture: e.g. that a C
> function pointer points into the text segment of the binary instead of e.g.
> a PLT, or that a loaded binary is placed continuously in memory (we only
> have one dli_fbase in DL_info). So imho it makes sense to not make this a
> standard Posix API.
>
> We (SAP) implemented dladdr atop of loadquery(), and this kind of works,
> although we had to add some hacks to handle both real code addresses and C
> function pointers. So the code is there, it is "just" a question of where to
> place it.
>
>
> I understand your desire to keep AIX pristine and clean, similarly,
> we should also keep OpenJDK sources clean, having 3 identical
> dladdr implementation, spread across the OpenJDK does not
> bode well.
>
> So, is it possible to park the sources in hotspot repo, and create a
> shared shared object, that can be suitably linked to the launchers,
> awt and hotspot to this library/object ?
I don't think this can be easily done with the current build system.
Remember for example that even such a sensitive part like jni.h is
still duplicated between the hotspot and the jdk repository:
hotspot/src/share/vm/prims/jni.h
jdk/src/java.base/share/native/include/jni.h
So before we envision a solution for the various dladdr
implementations for AIX we should really come up with a general way to
share code between hotspot and jdk. I've cc'ed build-dev because I
think this is to a big part a build/infrastructure issue. If somebody
has a good idea, please let me know :)
Regards,
Volker
>
> Thanks
> Kumar
>
>
>
>
> Kind Regards, Thomas
>
>> Thanks
>>
>> Kumar
>>
>>
>>>
>>> Regarding your change:
>>>
>>> - can you please move
>>>
>>> +#if defined(_AIX)
>>> +#include "java_md_aix.h"
>>> +#endif
>>> +
>>>
>>> from java_md_common.c to the end of
>>> java.base/unix/native/libjli/java_md.h. It will then be automatically
>>> included into java_md_common.c trough java.h which includes java_md.h
>>>
>>> Also, this version of dladdr is inherently not thread safe. I don't
>>> think that's a problem here, but it would be nice if you could quickly
>>> check if that's indeed true.
>>>
>>> Besides that, looks good.
>>>
>>> Thanks for fixing,
>>> Volker
>>>
>>>
>>>
>>>
>>> On Fri, Sep 16, 2016 at 11:58 AM, Langer, Christoph
>>> <christoph.lan...@sap.com> wrote:
>>>>
>>>> Hi,
>>>>
>>>> the fix for https://bugs.openjdk.java.net/browse/JDK-8165524 breaks the
>>>> AIX build as function dladdr is not available on AIX.
>>>>
>>>> There already exist ports of that API in hotspot and awt. With the
>>>> proposed change I duplicate the awt port to libjli. This is maybe only a
>>>> quick fix - eventually we should think about consolidating and using the
>>>> hotspot port in all places by exporting it from libjvm.so for AIX.
>>>>
>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8166189
>>>> Webrev: http://cr.openjdk.java.net/~clanger/webrevs/8166189.0/
>>>>
>>>> Thanks
>>>> Christoph
>>>>
>>>>
>>>>> -----Original Message-----
>>>>> From: core-libs-dev [mailto:core-libs-dev-boun...@openjdk.java.net] On
>>>>> Behalf
>>>>> Of Kumar Srinivasan
>>>>> Sent: Montag, 12. September 2016 22:57
>>>>> To: core-libs-dev <core-libs-...@openjdk.java.net>; Mandy Chung
>>>>> <mandy.ch...@oracle.com>; Chris Bensen <chris.ben...@oracle.com>
>>>>> Subject: RFR: 8165524: Better detect JRE that Linux JLI will be using
>>>>>
>>>>> Hello,
>>>>>
>>>>> I am sponsoring this changeset for Chris Bensen of the java packager
>>>>> team, please review fix for the launcher to better locate java.home.
>>>>>
>>>>> http://cr.openjdk.java.net/~ksrini/8165524/
>>>>>
>>>>> Thanks
>>>>> Kumar
>>
>>
>
>
