Re: [PATCH v2 3/3] posix: Use posix_spawn on system

[Florian Weimer <fweimer at redhat dot com>]

* Adhemerval Zanella:

> Although POSIX does not require, glibc system implementation aims to be
> thread and cancellation safe.  While reentracy handling does not require
> any direct change of current strategy, cancellation requires a posix_spawn
> to be cancellable.

I don't think this is actually true.  My understanding is that
posix_spawn does not block indefinitely in the parent, beyond things
that are not cancellation points anyway (resource allocation).  I/O
happens in the child process.  A posix_spawn that is a cancellation
point will lead to marginally faster reaction to a cancellation request.
But I think in practice, making the subsequent waitpid cancellable is
sufficient, and it should help to reduce the size of the patch.

Thanks,
Florian