Re: [patch 7/8] fdmap v2 - implement sys_socket2

From: Davide Libenzi
Date: Wed Jun 06 2007 - 18:52:44 EST


On Wed, 6 Jun 2007, David Miller wrote:

> From: Davide Libenzi <davidel@xxxxxxxxxxxxxxx>
> Date: Wed, 06 Jun 2007 15:30:31 -0700
>
> > This patch implement a new syscall sys_socket2(), that accepts an
> > extra "flags" parameter:
> >
> > int socket2(int domain, int type, int protocol, int flags);
> >
> > The flags parameter is used to pass extra flags to the kernel, and is
> > at the moment used to select the file descriptor allocations inside
> > the non-sequential area (O_NONSEQFD). The remaining parameters are
> > exactly the same as the ones of sys_socket().
> > The sys_accept() system call has been modified to return a file
> > descriptor inside the non-sequential area, if the listening fd is.
> > The sys_socketcall() system call has been also changed to support
> > a new SYS_SOCKET2 indentifier.
> >
> > Signed-off-by: Davide Libenzi <davidel@xxxxxxxxxxxxxxx>
>
> Since the valid range of "domain" values is quite small,
> we could avoid the new system call by cribbing some of the
> upper bits of the 'domain' argument.
>
> Valid existing programs pass in valid 'domain' values and
> thus will not set any of the new flags.
>
> Just an idea.

I have no huge preferences. If not the slight one of using the same flags
for open() and socket{2}() (O_NONSEQFD). If we overload socket() we may
need to fight with existing O_* flags. OTOH the current free ones are
pretty high in bits, so it may be OK too.



- Davide


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