On Thu, 21 Dec 2023 10:01:04 GMT, Thomas Stuefe <stu...@openjdk.org> wrote:
>>> > > What happens if we accidentally attempt to load a "real" static >>> > > library, which is also named *.a? Would dlopen() then crash? What would >>> > > happen? >>> >>> > I don't think the problem is with *.a . They would load as the default >>> > behaviour of the dlopen. It is only when the dlopen fails for *.so , we >>> > give another chance to check for .a file with the same name. >>> >>> No, what I meant, and what must be clarified before going forward with this >>> solution, is the following: >>> >>> * is _every_ `*.a` object on AIX loadable with `dlopen`, and will the >>> result be the same as when loading a `*.so` object >>> * or, if we present arbitrary `*.a` files to dlopen, is there a chance for >>> dlopen to crash or misbehave. >>> >>> Reason is that I was under the impression that *.a libraries are static >>> libraries and cannot be loaded dynamically. This is what you now try to do. >>> If we cannot safely answer this question, I would opt for a more narrow >>> solution by hard-wiring known alternative names. So, do the second *.a >>> attempt only for your `ibm_16_am.a` which you know works. That could also >>> be done in a reasonably maintainable manner. >>> >> In AIX, both static and dynamic libraries have *.a extension. And AIX also >> supports *.so files.Bascially shared objects in AIX have both *.a and *.so >> extension. Hence we need to implement this logic. >> If we try loading a static archive specifically ,how the dlopen would behave >> , that is something probably @JoKern65 can answer ? >> >> >>> > > Does this really have to be handled in the OpenJDK? What does J9 on AIX >>> > > do? Could this be done in a simpler way outside OpenJDK, e.g. by >>> > > providing an *.so variant of the library in question? Where does this >>> > > library come from? >>> >>> > I am not sure how J9 handles this. I would have to consult . >>> >>> J9 is Open Source, can't you just look? :) >> >> I did try comparing the file structures, and i do not see a similar file >> structure over there. >> I am unable to find the jvmTiAgent code and also os_aix file. So i am not >> sure which functions over there are doing the same functionality. You have >> any suggestion on how i can check and correlate ? >>> >>> > However as per current observation, this issue does not show up on >>> > Semuru. This issue is only happening on Adoptium. The team that release >>> > these file has always released *.a files which work fine for Semuru. >>> >>> I don't know what Semuru is. What is the context, is that a different VM? >>> Also OpenJDK? J9 derived? >> >> >> Semuru is J9 derived. > >> > > > What happens if we accidentally attempt to load a "real" static >> > > > library, which is also named *.a? Would dlopen() then crash? What >> > > > would happen? >> > >> > >> > > I don't think the problem is with *.a . They would load as the default >> > > behaviour of the dlopen. It is only when the dlopen fails for *.so , we >> > > give another chance to check for .a file with the same name. >> > >> > >> > No, what I meant, and what must be clarified before going forward with >> > this solution, is the following: >> > >> > * is _every_ `*.a` object on AIX loadable with `dlopen`, and will the >> > result be the same as when loading a `*.so` object >> > * or, if we present arbitrary `*.a` files to dlopen, is there a chance for >> > dlopen to crash or misbehave. >> > >> > Reason is that I was under the impression that *.a libraries are static >> > libraries and cannot be loaded dynamically. This is what you now try to do. >> > If we cannot safely answer this question, I would opt for a more narrow >> > solution by hard-wiring known alternative names. So, do the second *.a >> > attempt only for your `ibm_16_am.a` which you know works. That could also >> > be done in a reasonably maintainable manner. >> >> In AIX, both static and dynamic libraries have *.a extension. And AIX also >> supports *.so files.Bascially shared objects in AIX have both *.a and *.so >> extension. Hence we need to implement this logic. If we try loading a static >> archive specifically ,how the dlopen would behave , that is something >> probably @JoKern65 can answer ? > > Rather, this is a question you have to ask your collegues at IBM that develop > the AIX libc. > > Since AIX libc is not open source, we cannot look for ourselves, nor can > Joachim (her works at SAP). > >> >> > > > Does this really have to be handled in the OpenJDK? What does J9 on >> > > > AIX do? Could this be done in a simpler way outside OpenJDK, e.g. by >> > > > providing an *.so variant of the library in question? Where does this >> > > > library come from? >> > >> > >> > > I am not sure how J9 handles this. I would have to consult . >> > >> > >> > J9 is Open Source, can't you just look? :) >> >> I did try comparing the file structures, and i do not see a similar file >> structure over there. I am unable to find the jvmTiAgent code and also >> os_aix file. So i am not sure which functions over there are doing the same >> functionality. You have any suggestion on how i can check and correlate ? > > Someone must implement LoadLibrary. Try looking for places where dlopen() is > called. > >> >> > > However as per current observation, this issue does ... Hi @tstuefe Any further clarifications ,required for this change ? ------------- PR Comment: https://git.openjdk.org/jdk/pull/16604#issuecomment-1905320564
