24.07.2024 09:51, Greg KH пишет:
What caused this change/regression?
I have absolutely no idea. I've found it by debugging userspace, and wrote a test-case to make sure the problem is not in user-space.
And does any real-world programs rely on this?
dosemu
What exactly are you trying to determine with this ioctl test?
Whether it is a PTS (Pseudo-Tty-Slave), or a real comport with MSR signalling.
Is there a different way to determine that?
I am not aware of any "canonical" way of determining this. Maybe you tell me. :) So far the only fix I know, is to stop checking errno. But you return ENOTTY for a tty-associated fd (isatty(fd)==1), so I believe this is a bug in a kernel.
