Pseudo-device driver & select ??

[Aziz Kezzou]

> 
> Aziz Kezzou wrote:
> > Hi all,
> > I am trying to implement a small kld pseudo-device driver on FreeBSD 5.3 that
> > behaves just like a socket with regards to the select system call.
> >
> > Currently, I am using the sample echo pseudo-device driver from
> > http://www.freebsd.org/doc/en_US.ISO8859-1/books/arch-handbook/driverbasics-char.html
> >  as an example. However, whenever  I call select on the file
> > descriptor of "/dev/echo" it always returns even when there is no data
> > to be read.
> >
> > I looked at the socket code and it looks like I need to provide my own
> > "fo_select" function in the fileops data structure. Am i right ? How
> > do I do that ? The sample echo pseudo-device driver above uses
> > "struct cdevsw"  instead...
> >
> > Thanks
> > -aziz
> > _______________________________________________
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> >
> >
> look at spec_poll()
> I beleive that when your device is opened the fileops{} will
> point to the spec ops and you're code will be entered via
> spec_poll() - now you just need to implement the poll/select notion
> for your device.
>  

Thanks, 
Actually, il turned out to be very simple.
I needed only to provide a "d_poll" function as part of the structure
cdevsw, as follows :

/* Character device entry points */
static struct cdevsw echo_cdevsw = {
    .d_version = D_VERSION,
    .d_open = echo_open,
    .d_close = echo_close,
    .d_read = echo_read,
    .d_write = echo_write,
    .d_poll = echo_poll,
    .d_name = "echo",
};

with echo_poll :
static	int
echo_poll(struct cdev *dev, int events, struct thread *td)
{

  uprintf( "echo_poll called : data_available = %d!\n", data_available );
  if(data_available == 0)     
    return 0;  
  data_available = 0;  
  return 1;
}