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
Virtualization: qemu.org | libvirt.org
