Getting 'getty' to hangup dialup lines.

[chris at umcp-cs.UUCP]

I've been thinking about changing the vhangup system call to switch the
file descriptor over to an inode to /dev/null.  Here's my idea:  have
init call vhangup with a file descriptor that is open on /dev/null.
Have vhangup switch the inode given by the file pointer connected to
the terminal in question and the inode given by the file pointer given
to the vhangup system call.  Some fiddling with f_counts would need to
be done, of course, if multiple instances of the hung-up terminal are
lying around.  Finally, when the vhangup returns, init can just close()
the file descriptor, which will either point to /dev/null (no instances
of the hung-up terminal found) or to the terminal being hung-up.

Does anyone know of any potential problems with this (aside from init
compatibility issues)?
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci (301) 454-7690
UUCP:	{seismo,allegra,brl-bmd}!umcp-cs!chris
CSNet:	chris at umcp-cs		ARPA:	chris at maryland