Re: [microblaze-uclinux] Shared vs Static libraries?

[John Williams <jwilliams@xxxxxxxxxxxxxx>]

Hi John,

John McGrath wrote:

> I just sucessfully compiled the kernel / image for the current uClinux 
> distribution. I wanted to have a pertty minimal setup, but after 
> compilation I discovered the image.bin was 8.8 Mb!! I looked and saw the 
> kernel was about 1.2Mb, while the user applications took up the rest. On 
> looking in the romfs/bin directory I saw all the executable files there 
> were about 200-500K! for example cat was 159K while the cat on my linux 
> machine is 19K !! so clearly there is something going wrong. 

A few comments here.  You will see that many of the utilities in the 
romfs/bin directory are exactly the same size - these are links to the 
busybox executable, which is intended to combat exactly the issue you 
are raising.  In the actual romgfs image, there is (or should be) only a 
single instance of busybox, with a bunch of links to it to represents 
that various applets that it implements.

That said, if your final image.bin file is over 8mb in size, you must 
have a pretty serious collection of applications installed, or else some 
large data in the home/httpd directory or something.  This shouldn't 
happen in a "minimal setup" - my typical baseline build is normally 
around 2-2.5MB kernel included.  It seems likely that you've enabled 
something that yuo've forgotten, or there's something else going on.

Feel free to post the full directory listing of the romfs/bin directory 
on your host, it might tell us something.

> My guess it 
> is is statically linking the programs. I did not do anything (to my 
> knowledfge) to turn this on - but I assume it would not be the default, 
> as space is a premium! Anyone got any ideas on what this could be?

Yep - it's all statically linked.  Dynamic linking is possible on 
uClinux, but needs some software hackery and also support from the 
compiler for position independent code (I think).  As far as I know, 
m68k-nommu is the only arch to support dynamic libraries on uClinux.

Regards,
John

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