Re: Finding ld.so dynamic loader

Michael Eager
2008-01-30T16:53:02Z

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?