On 07/11/16 at 04:19pm, AKASHI Takahiro wrote:
> On Fri, Jul 08, 2016 at 11:48:44AM -0300, Thiago Jung Bauermann wrote:
> > Am Donnerstag, 07 Juli 2016, 14:12:45 schrieb Dave Young:
> > > If so maybe change a bit from your precious mentioned 7 args proposal like
> > > below?
> > >
> > > struct kexec_file_fd {
> > > enum kexec_file_type;
> > > int fd;
> > > }
> > >
> > > struct kexec_fdset {
> > > int nr_fd;
> > > struct kexec_file_fd fd[0];
> > > }
> > >
> > > int kexec_file_load(int kernel_fd, int initrd_fd,
> > > unsigned long cmdline_len, const char *cmdline_ptr,
> > > unsigned long flags, struct kexec_fdset *extra_fds);
> >
> >
> > Is there a way for the kernel to distinguish whether the process passed 5 or
> > 6 arguments? How can it know whether extra_fds is a valid argument or just
> > garbage? I think we have to define a new flag KEXEC_FILE_EXTRA_FDS so that
> > the process can signal that it is using the new interface.
>
> Good point. What I had in my mind is "open" system call.
> Glibc's implementation of open() checks for the second argument, flags,
> to determine whether or not the third argument, mode, is required.
>
> So our current consensus is that, for the time being, we will extend
> the existing system call interface to allow extra file descriptors,
> and *if* we really need a different type of parameters in the future,
> we will add another system call.
Sounds good to me.
>
> If we all agree, I can post a kernel patch for this change as a RFC.
> (I've already verified it with my prototype of kexec_file_load support
> on arm64.)
>
> Thanks,
> -Takahiro AKASHI
>
> > --
> > []'s
> > Thiago Jung Bauermann
> > IBM Linux Technology Center
> >
Thanks
Dave
