Szabolcs:

On 06/23/2016 11:15 PM, Szabolcs Nagy wrote:
> * Andrei Pozolotin <andrei.pozolotin@gmail.com> [2016-06-23 19:42:44 +0000]:
>> b) while at the same time musl ldd reporting that library dependency
>> tree is resolved with no error:
>>
>> lddtree /usr/lib/libswt-atk-gtk-4530.so
> that's not musl's ldd, but scanelf from pax-utils
thank you for pointing out.
> when debugging such a complicated setup the output
> of tools that may use subtly different library paths
> and symbol resolution logic is not very helpful.
ok, got it.
> ldd /usr/lib/libswt-gtk-4530.so
ldd /usr/lib/libswt-gtk-4530.so
        ldd (0x55e333e6c000)
        libc.musl-x86_64.so.1 => ldd (0x55e333e6c000)
> ldd /usr/lib/libswt-atk-gtk-4530.so
ldd /usr/lib/libswt-atk-gtk-4530.so
        ldd (0x55edc6edc000)
        libatk-1.0.so.0 => /usr/lib/libatk-1.0.so.0 (0x7fc763298000)
        libc.musl-x86_64.so.1 => ldd (0x55edc6edc000)
        libgobject-2.0.so.0 => /usr/lib/libgobject-2.0.so.0 (0x7fc763058000)
        libglib-2.0.so.0 => /usr/lib/libglib-2.0.so.0 (0x7fc762d6d000)
        libintl.so.8 => /usr/lib/libintl.so.8 (0x7fc762b5f000)
        libffi.so.6 => /usr/lib/libffi.so.6 (0x7fc762957000)
        libpcre.so.1 => /usr/lib/libpcre.so.1 (0x7fc7626fe000)
> would be more interesting..
>
> but even then we don't know what's going on
> (if libswt-gtk-4530.so is dlopened with RTLD_LOCAL
> then its libgobject dependency might not be visible
> to libswt-atk-gtk-4530)
OK. here is the story:

* java native interface: NativeLibrary.load()
http://hg.openjdk.java.net/jdk8u/jdk8u/jdk/file/74e5fc94c77b/src/share/classes/java/lang/ClassLoader.java#l1726

* java JNI implementation:
Java_java_lang_ClassLoader_00024NativeLibrary_load
http://hg.openjdk.java.net/jdk8u/jdk8u/jdk/file/74e5fc94c77b/src/share/native/java/lang/ClassLoader.c#l369

* libjvm.so entry point: os::dll_load
http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/file/tip/src/share/vm/prims/jvm.cpp#l3959

* libjvm.so linux implementation
http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/file/4529ee76d3f9/src/share/vm/runtime/os.hpp#l564
http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/file/4529ee76d3f9/src/os/linux/vm/os_linux.cpp#l1773
http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/file/4529ee76d3f9/src/os/linux/vm/os_linux.cpp#l1767
http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/file/4529ee76d3f9/src/os/linux/vm/os_linux.cpp#l1997
http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/file/4529ee76d3f9/src/os/linux/vm/os_linux.cpp#l1988

* and finally: it says: dlopen RTLD_LAZY:
http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/file/4529ee76d3f9/src/os/linux/vm/os_linux.cpp#l1988
void * result = ::dlopen(filename, RTLD_LAZY);

http://linux.die.net/man/3/dlopen
RTLD_LAZY: Perform lazy binding. Only resolve symbols as the code that
references them is executed.
If the symbol is never referenced, then it is never resolved.
(Lazy binding is only performed for function references;
references to variables are always immediately bound when the library is
loaded.)

RTLD_LAZY is good, right? :-)