Re: RFC: import of posix_spawn GSoC results

[Joerg Sonnenberger <joerg%britannica.bec.de@localhost>]

On Wed, Jan 25, 2012 at 01:14:18PM +0000, YAMAMOTO Takashi wrote:
> hi,
> 
> > On Wed, Jan 25, 2012 at 12:50:12PM +0100, Martin Husemann wrote:
> >> A working alternative aproach to this patch is to use a vfork based 
> >> emulation
> >> in userland only (FreeBSD is doing that). It is less kernel code, but to
> >> me sounds a bit hackish and/or fragile - maybe a matter of personal taste.
> > 
> > As said earlier, this can fail pretty badly when libraries (think pth)
> > overwrite system calls to do "transparent" operations behind the back.
> > Our mutexes for example are process specific.
> 
> i don't understand.  can you explain?
> 
> posix_spawn, if implemented in userland, is supposed to be in libc
> and thus can use the raw versions of system calls without being fooled
> by such libraries.

There is for example this "rump" thing that likes to mess with them even
on the raw level. I feel quite a bit more comfortable with a kernel
implementation. The issues Martin run into are bad refactoring and
fragile kernel code -- which should be cleaned up in any case.

Joerg