Fixing -pthreads (Re: ports and -current)

[Robert Watson]

On Wed, 24 Sep 2003, Dan Nelson wrote:

> Does it really matter if you end up linked to multiple threads
> libraries?  The first library providing a symbol wins, so the other
> shlibs just won't get used at all.  Libraries linked from the executable
> trump libraries linked from libraries, and LD_PRELOAD wins above all. 
> If one threads library exports a symbol not in the others, I'd call that
> an API bug in the first library. 
> 
> This should be no different from explicitly linking in dmalloc to
> override the malloc functions in libc, for example. 

One potential downside to the LD_PRELOAD approach is that it will only
work for applications that aren't setuid/setgid.  While today most of our
privileged and credential-munging applications aren't threaded, I'd like
to avoid precluding that in the future as much as possible.  What
mechanism should be used when LD_PRELOAD is being ignored due to
issetugid() returning true?

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert at fledge.watson.org      Network Associates Laboratories