Re: Introduce posix_spawn

[Eric Blake]

On 09/07/2018 09:44 AM, Eric Blake wrote:
> Adding gnulib:
>
> On 09/06/2018 11:37 PM, Barath Aron wrote:
> > On 9/7/18 4:54 AM, Dale R. Worley wrote:
> > > Couldn't you change the w.d. to the correct target, spawn, and then
> > > change the w.d. back?
> > Yes, one could do this.

Although it gets prohibitively expensive in a multi-threaded process to 
ensure proper locking between all threads that might want to use 
posix_spawn, since fchdir() affects global process state.

> > Actually, this particular problem can be easily solved on Threos, 
> > because the posix_spawn() API offers a function for this:
> > int posix_spawn_file_actions_addchdir_np(posix_spawn_file_actions_t* 
> > __restrict file_actions, const char* __restrict path);
> >
> > Note the "np" at the end, it means "non portable". I also found 
> > references on Oracle's webpage [1].
>
> It's useful enough that we may want to add support for this in gnulib, 
> whether or not other systems pick up on it.  (gnulib is already able to 
> overcome a lot of shortcomings in various platforms' posix_spawn)
In fact, it's so useful that I just proposed that POSIX standardize it, 
as well as fchdir:

http://austingroupbugs.net/view.php?id=1208

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
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