ioctl

hi!

in a new "driver" i'm processing ioctl requests like in do_ioctl from
tty.c:
------------------
PRIVATE int dm_ioctl(dp, m_ptr, safe)
struct driver *dp; /* pointer to driver structure */
message *m_ptr; /* pointer to control message */
int safe;
{
struct dm_ioctl *dmi;
int r;
int size = sizeof(struct dm_ioctl);

/* printf("dmtest: ioctl request 0x%x\n", m_ptr->REQUEST); */

switch (m_ptr->REQUEST) {
case DM_CREATE:

.....
}

....
}
--------------------

this works fine.
the problem is, I can't access the submitted struct.

I tried:
----------------
r = sys_safecopyfrom(m_ptr->IO_ENDPT, (vir_bytes) m_ptr-[color=blue]
>ADDRESS, 0,[/color]
(vir_bytes) &dmi, (vir_bytes) size, D);
----------------
but this always results in

EFAULT /* bad address */

on client side I do:
----
struct dm_ioctl *dmi = something_valid;
ioctl(fd, command, dmi);
----

what i'm doing wrong here?

m.

i'm still trying to access the ioctl request parameter.
from the message i have:

m_source = 1 (vfs)
IO_ENDPT = m_source
ADDRESS = 8 (increments on driver restart)
IO_GRANT = ADDRESS
POSITION = 122345 (changes on each ioctl)
COUNT = -237632658745 (changes on driver restart)

r = sys_safecopyfrom(m_ptr->IO_ENDPT, (vir_bytes) m_ptr->IO_GRANT, 0,
(vir_bytes) &dmi, (vir_bytes) size, D);

r = sys_vircopy( m_ptr->IO_ENDPT, D, (vir_bytes) m_ptr->ADDRESS,
SELF, D, (vir_bytes) &dmi, (vir_bytes) size);

both keep on failing with -14 (EFAULT) bad address


"memory", "tty" do it that way. is there something in between client
and driver? what's the meaning of the character for encoding the ioctl
requests?
i used:

#define DM_CREATE _IORW('X', 1, struct dm_ioctl)

shame on me.

solution:
i fuzzed up the datastructure on driver-side:
it has to be:

struct dm_ioctl dmi;

instead of a pointer to that struct.

now everything works like a charm.