I've thinked solution like this (similar to the one
taha has suggested):
static ssize_t read(struct file *file, char __user
*buf, size_t count,
loff_t *pos){
int element_size = sizeof(char)/ sizeof(pid_t) /*
To get the
array size for pids*/
int char_array_size = count / element_size;
char *char_array = (char*) pid_array;
/* .... This is your array ... fill what ever you
want to fill in
*/
}
but I've a doubt.
the array i had to pass to the user space is a array
of string, therefore of char pointers. So the solution
i've wrote above is sufficient?
thanks.
Vincenzo MAllozzi
--- taha hafeez <tawushafeez@xxxxxxxxx> ha scritto:
> On Mon, 2006-04-03 at 00:26 +0200, Vincenzo Mallozzi
> wrote:
> > --- taha siddiqi <tawushafeez@xxxxxxxxx> wrote:
> >
> > > Hi
> > >
> > > Same answer, "please explain the situation !!"
> > >
> > > taha
> > >
> > > Thanks.
> >
> > The array I want to pass from kernel space to user
> > space contains pid_t elements.
> > First, I pass the length of the array from user
> space
> > to kernel space.
> > Then, I build the array with the given length
> filling
> > it with the pid of processes I need to monitor.
> > Finally, I've to pass this array of pids to the
> user
> > space.
> > I hope I've well explained the situation.
> > Thanks all.
> > Vincenzo Mallozzi.
> >
>
> Well, I think I get you now....
>
> Correct me if I am wrong...
>
>
> data buffer
> USER_SPACE ------------> KERNEL SPACE [fill data
> with pid_t]
> ^ |
> | |
> *------<----------------*
> data buffer
>
> Why do we need to pass the data buffer to kernel ?
> Does it contain any information that kernel needs ?
> if not, then that step can be avoided ?
>
> Then you just need a read call implementation of
> struct file_operations {}.
>
> taha
>
>
>
>
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