RE: [PATCH 2.6.9] fork: add a hook in do_fork()

[Guillaume Thouvenin]

On Tue, 2004-11-23 at 01:59 -0800, Hua Zhong wrote:
> > +	static int fork_hook_id = 0;
> > +
> > +	/* We can set the hook if it's not already used */
> > +	if ((func != NULL) && (fork_hook_id == 0)) {
> > +		fork_hook = func;
> > +		fork_hook_id = id;
> > +		return 0;
> > +	}
> 
> What happens if two modules are calling the same function at the same time?

You are right there is a problem. I need to add a lock.
 
> > +
> > +	if (fork_hook != NULL)
> > +		fork_hook(current->pid, pid);
> > +
> >  	return pid;
> 
> What happens if the module is unloaded between the test and the call to
> fork_hook?

Again you are right and I need to protect that. 

In fact, Greg suggests to use LSM hook and it seams that it does what I
need. So my patch is obsolete now. 

Thank you to everybody for your help,
Best Regards,

Guillaume

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