Re: In-kernel process exit hooks?

[David Holland <dholland-tech%netbsd.org@localhost>]

On Thu, Jan 07, 2016 at 07:34:33AM +0800, Paul Goyette wrote:
 > Based on internal implementation of filemon(4), there is an ordering
 > requirement imposed on the sequence of events that occur when a process
 > using /dev/filemon exits.  In particular, the file descriptor on which the
 > device is open needs to be closed prior to closing the descriptor to which
 > avent/activity records are being logged.  (Otherwise, because of an extra
 > reference on the log file, fd_close() will hang indefinitely.)

Looking at the filemon code... it is completely wrong. It should not
be using file handles like that, especially not in a device driver.
Rather than adding new hacks to the system to work around it being
silly, it should be redone properly.

For an example of the right way to do this kind of thing, look in
kern_acct.c.

-- 
David A. Holland
dholland%netbsd.org@localhost