Re: [gentoo-user] Per package /bin/sh selection

[Mike Gilbert]

On Wed, Apr 8, 2020 at 1:17 PM Joerg Schilling
<Joerg.Schilling@××××××××××××××××.de> wrote:
>
> Mike Gilbert <floppym@g.o> wrote:
>
> > Wikipedia says that dash is a fork of NetBSD's ash, and I do see tests
> > in their CVS repo. That might be worth looking into.
> >
> > http://cvsweb.netbsd.org/bsdweb.cgi/src/tests/bin/sh/
>
> I see this is the variant from Rihard Elz, so it may make sense.
> The original ash is too buggy as a reference.
>
> > > When ever I change something in bosh, I run the unit tests to verify that I did
> > > not introduce a bug. One of the unit tests is to run a configure and compare
> > > the results with the results frm a reference shell.
> > >
> > > BTW: Did you ever think about replacing dash by bosh?
> >
> > We use bash as the default /bin/sh, but users are free to replace it
> > with whatever shell they like, so long as it is reasonably
> > POSIX-compliant. Other shells are obviously less tested in Gentoo.
>
> Well, bosh has been tested to work as /bin/sh on Gentoo.
> BTW: On Solaris, bosh is faster than dash (because Solaris has a fully working
> vfork()). On Linux bosh is "only" of the same speed as dash since vfork() on
> Linux does not borrow the parents address space description but copies it.

Is that also true of clone(CLONE_VM|CLONE_VFORK)? Recent versions of
glibc use this to implement the posix_spawn() function.