librt and libpthread in alternate prefix
Ethan Grammatikidis
eekee57@fastmail.fm
Fri May 15 23:32:00 GMT 2009
On Thu, 14 May 2009 20:00:36 -0400
Poor Yorick <org.sourceware.libchelp@pooryorick.com> wrote:
> Mike Frysinger wrote:
> > On Tuesday 12 May 2009 10:15:16 Poor Yorick wrote:
> >> Mike Frysinger wrote:
> >> > On Monday 11 May 2009 23:34:16 Poor Yorick wrote:
> >> >> Because my goal is to build a software collection in an alternate
> >> >> library path which uses its own glibc, I'm trying to get the new loader
> >> >> to work from the alternate location without setting --library-path.
> >> >
> >> > so use a wrapper script that builds paths using $0
> >>
> >> That's a kludge that doesn't work well, since wrapper scripts aren't
> >> suitable for the #! line.
> >
> > i dont really know what you're talking about here. #!/bin/sh works just fine.
>
> I mean that I can't wrap binaries compiled against the alternate glibc in a
> script that calls the real binary using the new loader. For example, if I wrap
> awk in a script called awk_new, I can't do this:
>
> !# /path/to/alternate/awk_new
>
> because the !# mechanism requires a binary, not a script.
False, you *can* call a script from the #! line.
I suspected your permission denied error is something else, and recalling that I once got permission denied errors under very wierd, non-obvious circumstances, I eventially remembered it can be caused by a peculiar dynamic-linking problem. :)
/lib/ld.so (actually /lib/ld-<version>.so) handles most of the dynamic linking in a system, but importantly it itself is a dynamically-linked library. It can't load itself, so what happens? It's loaded by a much more primitive kernel-based mechanism. When things go wrong the only error this primitive mechanism can give is permission denied!
I guess that whatever the binary is that finally ends up executing your wrapper scripts, it's somehow finding the wrong ld.so.
--
Ethan Grammatikidis
The lyf so short, the craft so long to lerne. -- Chaucer
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