[PATCH] [msan] Intercept *getxattr and *listxattr.

[Sergey Matveev]

  > In that case we need to write max(size, res), or something like that.

  This would attempt to unpoison more memory than we actually have.

  I think the wording is clear: if a buffer of zero size is passed, then the desired size is returned. Nothing is written to the buffer, it just tells us what kind of buffer is wanted. So no need to unpoison anything in this case.

http://llvm-reviews.chandlerc.com/D2642