mod.std.unix P1003 job control proposal (Brett Galloway)
Guest Moderator, John B. Chambers
std-unix at ut-sally.UUCP
Tue Nov 18 04:50:09 AEST 1986
References:
>From nsc!hplabs!hpda!hpisoa1!davel at pyramid.UUCP Wed Nov 12 16:57:34 1986
Cc: gorodish!guy at sun.UUCP
Date: Wed, 12 Nov 86 10:42:53 -0800
> guy at sun.com (Guy Harris) writes:
> > vhangup() is indeed desirable. It is not required in POSIX because it is
> > not supported on System V and, indeed, breaks System V compatiblity.
>
> Only if you define "System V compatibility" as "behaves exactly the same as
> some particular implementation of System V".
It is true that vhangup() does not break any documented behavior in
System V or the SVID. However, the System V implementations I am familiar
with (mainly ATT VAX releases) allow access to open login tty file
descriptors after logout (/dev/tty is the exception).
Again, vhangup() is, in my opinion, preferable for security reasons. I
do not consider the alternate behavior present in at least some System V
ports worth requiring.
> "vhangup" does two things; it
> sends a SIGHUP to the process group of the terminal in question (which is,
> in fact, similar to what S5 does automatically) and it invalidates file
> descriptors that refer to the terminal.
>
> Some System V implementations do not do this, ...
I'm curious; could you list some of the System V implementations which
disallow access to the login tty (via, e.g., stdout, not /dev/tty) after
logout? I.e., System V's that have vhangup()-like behavior?
-Dave Lennert HP ihnp4!hplabs!hpda!davel
Volume-Number: Volume 8, Number 55
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