libbusybox is back; "individual" mode is introduced

[Bernhard Fischer]

On Thu, Oct 11, 2007 at 06:49:07PM +0100, Denys Vlasenko wrote:
>On Thursday 11 October 2007 15:23, Bernhard Fischer wrote:
>> >I looked into making libbusybox.so executanle itself, but
>> >it looks like that needs a lot of linker magic for questionable
>> >gain - I can have tiny (less than 3k) "busybox" executable
>> >linked against it providing the same functionality.
>> >
>> >Any specific reasons why do you like to have
>> >PIE busybox-which-is-also-libbusybox?
>> 
>> I don't have a real use-case right now (I used to do this a while back
>> for XXX_main and some helpers from libbb, fwiw)
>> but it could be used to either
>> -) use XXX_main in other progs
>> -) use stuff from {*/,}lib*/*c in other progs
>> -) replace zlib, provided that a compatible interface is exported (not
>> yet implemented, IIRC)
>
>As of today, *all* busybox code goes to libbusybox
>if CONFIG_BUILD_LIBBUSYBOX=y, busybox binary is only
>a really trivial thunk:
>
>   text    data     bss     dec     hex filename
>    988     260       4    1252     4e4 busybox
> 745254   12570   12032  769856   bbf40 libbusybox.so.1.8.0.svn

Ah, i see.
>
>This basically gives you what you want in terms
>of minimizing size of the on-disk files.
>
>PIE approach will combine these two files. Maybe it is
>aesthetically nicer, but no real win in size.

PIE is nicer IMHO, yes.
>
>> The zlib case would be a very, very nice thing to have, IMO
>
>You mean - ability to use zlip (de)compressor from busybox?

yes, exactly. think
$ ln -s busybox libz.so
and export deflate() inflate() and some other "important" funcs that are
exported by zlib.
>
>> (in case you 
>> already drained your TODO list too much :)
>
>My TODO list is
>- have NOMMU test config running in qemu (need help with this)
>- attack "invisible" sources of mem consumption,
>  like stack usage
>- phase out lash in favor of hush
>- improve hush

I hope you reverse the order of the last two points ;) But we already
talked about lash still being smaller than hush (didn't look recently
though).