PING: RFR: 8241439: jdk.NativeLibraryEvent hooks all opened regular files

[Yasumasa Suenaga]

PING: Could you review it?

   JBS: https://bugs.openjdk.java.net/browse/JDK-8241439
   webrev: http://cr.openjdk.java.net/~ysuenaga/JDK-8241439/webrev.01/


Yasumasa


On 2020/04/09 16:00, Yasumasa Suenaga wrote:
> Hi all,
> 
> Please review this change:
> 
>    JBS: https://bugs.openjdk.java.net/browse/JDK-8241439
>    webrev: http://cr.openjdk.java.net/~ysuenaga/JDK-8241439/webrev.00/
> 
> HotSpot has os::get_loaded_modules_info() to get all loaded native libraries, however it would call callback in twice on same library on Linux. Also it would call callback even if the file is not a library.
> 
> We can see this problem in jdk.NativeLibrary JFR event as below:
> 
> 
> ```
> jdk.NativeLibrary {
>     startTime = 16:59:06.621
>     name = "/usr/lib64/libc-2.30.so"
>     baseAddress = 0x7FDB06ACC000
>     topAddress = 0x7FDB06AF1000
> }
> 
> jdk.NativeLibrary {
>     startTime = 16:59:06.621
>     name = "/usr/lib64/libc-2.30.so"
>     baseAddress = 0x7FDB06AF1000
>     topAddress = 0x7FDB06C40000
> }
> 
>      :
> 
> ```
> 
> ```
> jdk.NativeLibrary {
>     startTime = 16:59:06.621
>     name = "/home/ysuenaga/OpenJDK/jdk/build/linux-x86_64-server-fastdebug/images/jdk/lib/server/classes.jsa"
>     baseAddress = 0x800000000
>     topAddress = 0x800007000
> }
> ```
> 
> This change uses dl_iterate_phdr() to get them, so these problem has gone.
> 
> 
> Thanks,
> 
> Yasumasa