search for: xstdopen

...uring they are open means we don't have to worry about other fd creation events accidentally colliding). We also want to ensure that nothing opens into the slot for stderr, as any error message we produce might then corrupt the wrong file. https://git.savannah.gnu.org/cgit/gnulib.git/tree/doc/xstdopen.texi is an interesting read on the matters of dealing with closed fds; but as we are unable to use gnulib for licensing reasons, we'll just roll our own solution. Note that checking that we have valid fds on entry covers most cases, but there is still one more situation to worry about (in fact...