RFR: 8166189: Fix for Bug 8165524 breaks AIX build
Kumar Srinivasan
kumar.x.srinivasan at oracle.com
Wed Sep 28 17:13:51 UTC 2016
One thing I missed to mention, the fix for 8165524
is primarily to assist the packager tool, which deploys client
side/JavaFX based applications.
If this tool is not relevant and does not exist on AIX. Then at
a minimum the dladdr call can either be dynamically located/invoked
using dlsym, or simply have the AIX version of dladdr return JNI_FALSE
always, only for the launcher of course.
Thanks
Kumar
>
> 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 ?
>
> 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.langer at sap.com <mailto:christoph.langer at sap.com>>
>> wrote:
>>
>> Hi,
>>
>> the fix for
>> https://bugs.openjdk.java.net/browse/JDK-8165524
>> <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
>> <https://bugs.openjdk.java.net/browse/JDK-8166189>
>> Webrev:
>> http://cr.openjdk.java.net/~clanger/webrevs/8166189.0/
>> <http://cr.openjdk.java.net/%7Eclanger/webrevs/8166189.0/>
>>
>> Thanks
>> Christoph
>>
>>
>> -----Original Message-----
>> From: core-libs-dev
>> [mailto:core-libs-dev-bounces at openjdk.java.net
>> <mailto:core-libs-dev-bounces at openjdk.java.net>] On Behalf
>> Of Kumar Srinivasan
>> Sent: Montag, 12. September 2016 22:57
>> To: core-libs-dev <core-libs-dev at openjdk.java.net
>> <mailto:core-libs-dev at openjdk.java.net>>; Mandy Chung
>> <mandy.chung at oracle.com
>> <mailto:mandy.chung at oracle.com>>; Chris Bensen
>> <chris.bensen at oracle.com
>> <mailto:chris.bensen at 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/
>> <http://cr.openjdk.java.net/%7Eksrini/8165524/>
>>
>> Thanks
>> Kumar
>>
>>
>>
>
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