Re: Finding ld.so dynamic loader

[Michael Eager <eager@eagercon.com>]

It seems that as soon as I ask a question, the answer drops into
my lap.  There's a "set solib-absolute-prefix" command which
sets the prefix to use to find the shared libraries.

Michael Eager wrote:
> I've been reading through solib_open() in solib.c and the way
> that the code searches for the dynamic loader doesn't make sense
> to me, especially when using gdbserver to debug a program on
> a remote system.  Perhaps someone can explain to me why it is correct.
> 
> solib_open() is called by enable_break() with the name of
> the dynamic loader, say, "/lib/ld.so.1".  The comments at
> the top of solib_open() say:
> 
>  125    * If there is a solib_absolute_prefix and path is absolute:
>  126    *   Search for solib_absolute_prefix/path.
>  127    * else
>  128    *   Look for it literally (unmodified).
>  129    * Look in SOLIB_SEARCH_PATH.
>  130    * If available, use target defined search function.
>  131    * If solib_absolute_prefix is NOT set, perform the following two 
> searches:
>  132    *   Look in inferior's $PATH.
>  133    *   Look in inferior's $LD_LIBRARY_PATH.
> 
> If solib_absolute_prefix is empty (true for almost all targets) and
> /lib/ld.so.1 exists on the host system, this will be opened in
> preference to either one specified on the SOLIB_SEARCH_PATH or using a
> target search path.
> 
> This seems incorrect.  The dynamic loader on the host system
> may not be the same as on the target system, and in the case
> of cross development, may not even have the same architecture.
> Shouldn't the search using the unmodified name be the last choice,
> not the first?
> 
> Can someone explain to me how gdb is supposed to find the correct
> ld.so or why I'm looking at this incorrectly?
> 


-- 
Michael Eager	 eager@eagercon.com
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