Subject: Re: RFC: migration to a fully dynamically linked system
To: None <email@example.com>
From: None <firstname.lastname@example.org>
Date: 12/21/2001 10:59:41
At Fri, 21 Dec 2001 17:43:15 +0000 (UTC), "Jason R Thorpe" wrote:
> On Fri, Dec 21, 2001 at 08:36:44AM -0800, Greywolf wrote:
> > Why does nsswitch need to be part of a dynamic library? Why can we not
> > just do the lookup in the nsswitch.conf and behave accordingly?
> Because then for every possible auth type you want to provide, you
> have to have it included in libc.
It's actually worse than that. it gets included in libc... and
because of the inherent nature of the nsswitch code, the generic
e.g. passwd routines have to reference _all_ of the back-end passwd
routines. Thinking about it, since those need to do nsswitch parsing
etc., probably all of the _other_ stuff understood by nsswitch has to
get pulled in as well.
It's a fairly huge amount of code. For a good time, compare the size
of fsck_ffs compiled with and without -DSMALL.
text data bss dec hex filename
278495 3416 19772 301683 49a73 fsck_ffs.LARGE
112113 1536 7324 120973 1d88d fsck_ffs.SMALL
If you look at the code #ifdef'd by SMALL, you'll note that it's
if ((pw = getpwuid((int)iswap32(dp->di_uid))) != 0)
printf("%s ", pw->pw_name);
That 'getpwuid()' call more than doubles the size of fsck (which isn't
a tiny/trivial program to begin with).