Re: [Gaim-devel] Binary relocatability patch

[Mike H. <mi...@th...>]

On Sat, 2004-01-03 at 00:17, Ethan Blanton wrote:
> We cannot depend on ELF binaries, for starters.

This patch only changes Gaims behaviour on Linux, and all Linux distros
that it's interesting for Gaim to run on use ELF.

> Likewise, we cannot
> depend on dlopen() and family to either exist or work consistenly.

Systems with broken or non-existant dladdr() are not Linux so the patch
code would not be used or enabled.

> Similarly, /proc may or may not exist and may or may not contain the
> information you are looking for.

This would be the case on very few systems - on these systems the prefix
detection can simply be disabled by recompiling.

> As you say, some of this can be detected at runtime (such as the lack
> of /proc); the rest of it can likewise be detected at compile time
> (binary format, dl*) ... but that's even uglier than the problem
> you're trying to "fix", in my opinion.

Detecting the presence of features at runtime is done all the time and
is not ugly - Gaim already does this for MSN/SSL support, for instance.

> I remain an advocate of a --prefix runtime argument-type solution to
> this problem.

This simply shifts responsibility for determining the prefix to a
wrapper script, which requires even more ugly hacks like scanning the
path. The ELF base address approach is 100% reliable on Linux systems
and can be cleanly implemented in C.

thanks -mike