Re: [RFA] Introduce solib_loaded observer

[Mark Kettenis <mark dot kettenis at xs4all dot nl>]

   Date: Sun, 9 Jan 2005 17:37:33 -0500
   From: Daniel Jacobowitz <drow@false.org>

   On Sun, Jan 09, 2005 at 02:05:15PM +0100, Mark Kettenis wrote:
   >
   > Calling the observer after loading the symbols isn't possible.  You
   > can set "auto-solib-add" to 0, and then the symbols will never be
   > loaded at all.  So you'll always have to force loading the symbols
   > from within your observer anyway (but you only have to do so for the
   > threads library).  From a code perspective the point where the
   > notification is called is the most logical.  And that way it's less
   > likely that we see "auto-solib-add" related bugs ;-).

   At the same time, I worry that it's going to be confusingly
   inconsistent - for instance, I would have expected turning off
   auto-solib-add to prevent loading symbols for libpthread!  Or at least,
   loading of full symbols (all libthread_db on GNU/Linux really needs are
   a couple of minsyms).

We should try to be as consistent as possible.  The current situation
is very inconsistent too: if you turn off auto-solib-add, you won't
get thread debugging support.  It's true that for debugging support
you usually only need a few minimal symbols.  I considered rolling my
own BFD-based lookup function, but I suspect that would result in a
serious performance hit because I'd lose the benefit of caching.

   I don't think "isn't possible" is accurate; there are only two callers
   of update_solib_list, and one of them wants to read the symbols.  That
   could be pushed down into an argument to update_solib_list.  Would that
   be better?

Because of the auto-solib-add issue I don't think it is, but given the
right arguments I think you can make me think differently.  What to
the others think of this?

Mark