Comment by duskwuff
4 days ago
As an aside:
> ... copy the binaries uucp, uuname, uustat, and uux from /usr/bin to /usr/local/bin and the binaries uucico and uuxqt from /usr/sbin to /usr/local/bin ...
This should be your hint that UNIX certification is more of a box-checking exercise than a real test of functionality. UUCP has been functionally obsolete since at least the mid-1990s; it's surprising that macOS even bothers shipping its binaries, and it's exceptionally silly that UNIX certification requires it to be present and installed in /usr/local.
It doesn't look like the certification requires those UUCP binaries to be in /usr/local, that's just where you have to put them on macOS to be able to `chmod +s` them, which is what the certification actually requires. Less arbitrary, but even more clearly obsolete and bad practice for a modern OS.
Oh, that makes more sense. I'm still not sure why you couldn't give the binaries setuid in their default locations, given that compliance testing also requires SIP to be disabled - but, in any case, at least they aren't setuid by default.
Anyways, "real UNIX systems must implement UUCP" is still extremely silly.
Disabling SIP still leaves the root filesystem as read-only and signature-checked (this is referred to as SSV, 'signed system volume'). There is a separate command to disable SSV, but it breaks the ability to install OS updates and is rarely used. /usr/local is one of the paths that's redirected to the read-write data volume.