Messages in this thread |  | | Date | Tue, 7 May 1996 12:47:10 -0400 | From | "Theodore Ts'o" <> | Subject | Re: Bug in serial line hangup code ? |
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Date: Tue, 7 May 96 07:44 BST From: Peter Fox <fox@roestock.demon.co.uk>
On the other hand, it seems to have fixed all those annoying little messages from pppd: tcgetattr: I/O error, because my monitor process prevents the port being shutdown on hangup. (pppd-2.2.0c)
That's a bug in pppd; it shouldn't be logging that error in the first place.
Obviously, it is meaningless for two processes to have the same port open for I/O, which is why there are lockfiles etc, but I've certainly found the ability to monitor the port useful, so if there is a way to let a process do ioctls etc, immune from hangups etc, then please do revisit the hangup code.
Once a hangup occurs, the process doesn't have the port open for I/O. That's the way it is for security reasons. What would be useful for your port monitoring program will also be useful to an attacker who wishes to run a port monitoring program....
- Ted
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