[systemd-devel] Please proof-read: systemd’s dependencies and installation footprint

[Kay Sievers]

On Tue, Jun 11, 2013 at 5:18 AM, Cristian Rodríguez
<crrodriguez at opensuse.org> wrote:
> El 10/06/13 15:25, Kay Sievers escribió:
>
>> On Mon, Jun 10, 2013 at 7:26 PM, Cristian Rodríguez
>> <crrodriguez at opensuse.org> wrote:
>>>
>>> El 10/06/13 06:17, Lennart Poettering escribió:
>>
>>
>>>> Hmm, you list that our daemons would require pcre? That's weird, we
>>>> don't really do that. That sounds like a bug,
>>
>>
>>> Sounds more like something in the dependency chain is not linked with
>>> as-needed causing a mess.
>>
>>
>> Seems selinux does add that dependency, and which cannot be eliminated
>> with as-needed as soon as any selinux things are used:
>>
>>    $ echo 'int main(int argc, char *argv[]) { return 0; }' > main.c;
>> gcc main.c -o main -lselinux; ldd main
>>         linux-vdso.so.1 =>  (0x00007ffff33fe000)
>>         libselinux.so.1 => /lib64/libselinux.so.1 (0x00007fd2232b1000)
>>         libc.so.6 => /lib64/libc.so.6 (0x00007fd222ef1000)
>>         libdl.so.2 => /lib64/libdl.so.2 (0x00007fd222cec000)
>>         libpcre.so.1 => /lib64/libpcre.so.1 (0x00007fd222a88000)
>>         libpthread.so.0 => /lib64/libpthread.so.0 (0x00007fd22286c000)
>>         /lib64/ld-linux-x86-64.so.2 (0x00007fd2234ef000)
>>
>> Kay
>
>
> hrmmm..
>
>
> echo 'int main(int argc, char *argv[]) { return 0; }' > main.c;
>  gcc -Wl,--as-needed main.c -o main -lselinux; ldd main
>         linux-vdso.so.1 (0x00007fff3f9fe000)
>         libc.so.6 => /lib64/libc.so.6 (0x00007f6b3364a000)
>         /lib64/ld-linux-x86-64.so.2 (0x00007f6b339f7000)
>
> no linkage with selinux, as expected since our little main.c does not use
> selinux.

That's right, it does not pull-in selinux and as-needed can still get rid of it.

But as soon as selinux is needed, pcre is also pulled-in into the main
binary by this:
  $ nm -D /usr/lib64/libselinux.so.1 | grep pcre
                 U pcre_compile
                 U pcre_exec
                 U pcre_free
                 U pcre_free_study
                 U pcre_study

Kay