Re: thread rant

From: Alexander Viro (viro@math.psu.edu)
Date: Sat Sep 02 2000 - 10:53:43 EST


On Sat, 2 Sep 2000, Jamie Lokier wrote:

> dean gaudet wrote:
> > an example of brokenness in the traditional fd API is close-on-exec --
> > there's a race between open()/socket()/pipe() and fcntl(FD_CLOEXEC) during
> > which if another thread does a fork() it's possible the child will inherit
> > an fd it shouldn't... working around it is painful. the model which

Really? Like, say it, close() before exec()?

> > NT/OS2 use for creating a new process scales better in the 99.99% case of
> > stdin/out/err -- you only specify those fds you want to keep in the new
> > process.
>
> An obvious solution presents itself. O_CLOEXEC.

Even more obvious solution: close what you need to close if you have
sensitive descriptors around. Close-on-exec is a kludge. If you have
sensitive pieces of descriptor table you want to do some other things too
- e.g. make sure that it gets unshared before exec(). Because new
descriptors of that kind are very likely to follow...

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