Re: Lost O_NONBLOCK (Bug?)

[Philippe Troin <phil@fifi.org>]

Jason Gunthorpe <jgg@debian.org> writes:

> On 12 Apr 2001, Philippe Troin wrote:
> 
> > Apt I guess ? It has a very strange behavior when backgrounded...
> 
> Not really, just want it tries to run dpkg it hangs.
> 
> > > The last read was after the process was forgrounded. The read waits
> > > forever, the non-block flag seems to have gone missing. It is also a
> > > little odd I think that it repeated to get SIGTTIN which was never
> > > actually delivered to the program.. Shouldn't SIGTTIN suspend the process?
>  
> > Strace can perturbate signal delivery, especially for terminal-related
> > signals, I wouldn't trust it...
> 
> I know, the problem still happens without strace.

Do you have a snippet that can reproduce the problem ? Does this
happens only with 2.4, or both 2.2 and 2.4 have the problem ?

> > O_NONBLOCK is not lost... Attempting to read from the controlling tty
> > even from a O_NONBLOCK descriptor will trigger SIGTTIN.
> 
> I don't really care about the SIGTTIN, what bugs me is that the read that
> happens after the process has been foregrounded blocks - and that should
> not be.

True.

8< snip >8

Phil.