pty/tty or signal strangeness, or grep/bsdgrep bug?

[Ed Schouten]

Hi all,

2012/10/23 Ed Schouten <ed at 80386.nl>:
> Will try to come up with a decent patch tomorrow evening.

Ahem; the day after tomorrow. Jeremy, could you please try the following patch?

http://80386.nl/pub/tty-bg-read.txt

I decomposed the TTY read routine into four separate functions to
improve clarity. While this was initially true, I think it's a pity
the four functions are constantly becoming a bit more complex.

The same issue is also present on the output path, but I have no idea
how realistic/hard it is to fix this issue. Also, it might not really
be an issue in practice. If you do a large write and become a
non-foreground process group, you might be able to circumvent TOSTOP
while the write() is in transit.

Fixing this might be tedious, because we currently enforce that writes
to a TTY are serialized. Blocking inside the write() might then cause
a deadlock. But in my opinion, I would prefer the serialization over
the enforcing of TOSTOP.

Thanks again for reporting the issue!

-- 
Ed Schouten <ed at 80386.nl>