Re: large overhead in libmount

[Karel Zak]

On Thu, Apr 02, 2015 at 12:36:33PM +0100, Pádraig Brady wrote:
> >> $ ldd src/du
> >> linux-vdso.so.1 =>  (0x00007fff76ca8000)
> >> libc.so.6 => /lib64/libc.so.6 (0x00007f2a1f742000)
> >> /lib64/ld-linux-x86-64.so.2 (0x00007f2a1fd61000)
> >>  libmount.so.1 => /lib64/libmount.so.1 (0x00007f2a1faff000)
> >>   libblkid.so.1 => /lib64/libblkid.so.1 (0x00007f2a1f501000)
> >>   libuuid.so.1 => /lib64/libuuid.so.1 (0x00007f2a1f2fc000)
> >>   libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f2a1f0d7000)
> >>   libpcre.so.1 => /lib64/libpcre.so.1 (0x00007f2a1ee69000)
> >>   liblzma.so.5 => /lib64/liblzma.so.5 (0x00007f2a1ec44000)
> >>   libdl.so.2 => /lib64/libdl.so.2 (0x00007f2a1ea40000)
> >>   libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f2a1e823000)
> > 
> > The problem is libselinux, but on selinux based system you have all the
> > libraries already in memory for many another tools...
> 
> Indeed.
> 
> I see libmount links with libselinux to use selinux_trans_to_raw_context()
> for the context= mount options etc.

The ideal solution would be to avoid this selinux context translation
at all. It would be nice to make it possible to send context= to kernel 
as specified on command line. Dan, any comment? (dwalsh added to CC:)

It's also painful that so generic (often used) library like selinux
has so many additional dependencies.

> I suppose one could split libmount
> to avoid that dependency, though it's probably not worth it for this case at 
> least?

Well, I can create a fallback for this stuff and move the translation code to
mount(8) only... then libmount will be without the dependence.

    Karel

-- 
 Karel Zak  <address@hidden>
 http://karelzak.blogspot.com