Re: Proposal for new syscalls: getrusagex and waitx

[David Laight <david%l8s.co.uk@localhost>]

On Sat, Oct 18, 2008 at 06:10:23PM +0000, David Holland wrote:
> On Thu, Oct 16, 2008 at 10:09:39PM -0700, Matt Thomas wrote:
> > I'd to add return some additional data in getrusage or wait4.  Extending 
> > struct rusage seems to be a losing proposition since I will need to version 
> > the syscalls and provide compatiblity shims.  I might as well just add 
> > variants that return proplib dictionaries with the information.
> >
> > int getrusagex(int who, struct plistref *dict)
> > int waitx(pid_t wpid, int *status, int options, struct plistref *rusage);

What is a 'struct plistref' ?
If it contains pointers to other user-space structures it will be a PITA
for the kernel to process.
If the kernel has to write into it how does it know how much space there is?
If the kernel has to modify a complex structure that the app partially
initialises it a a PITA for both the kernel and app.

> That should be wait5, for consistency with the various other forms of
> wait.

Except that posix/SuS might decide to use wait5() for something else!

        David

-- 
David Laight: david%l8s.co.uk@localhost