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Date: Sun, 24 Aug 2008 23:16:58 -0700 (PDT)
From: Matthew Dillon <dillon@apollo.backplane.com>
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Subject: Re: Magic symlinks redux
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    The only issue we hit with per-process varsyms is that to really
    be useful the shells need built-ins to set the process-space variables,
    since doing so as an exec'd subprocess will not effect the shell or its
    children.  We have no plans to allow one process to modify another
    process's varsyms as that would cause significant security issues.

    In fact, even the per-user variables might have security issues
    (e.g. common-run 'nobody' user utilities, and so forth, for which
    a pseudo-userid has not been created).  I'm kinda thinking of removing
    per-user variables despite the usefulness.

    There have been various circumstances where we've thought varsyms
    would be useful, but ended up not needing to use them.

    Right now we are looking at possibly using them to point /usr/lib and
    friends to select 32 or 64 bit ABI library paths, and have the kernel
    automatically set a varsym when exec'ing an ELF program to the
    program's ABI.  Doing this would allow 32 and 64 bit program, library,
    and package sets to be run and maintained side-by-side.

					    -Matt