Hell all

I am new to kernel programming and I have done some application
programs interacting to drivers (storage driver's hda, hdb)
Now that I am involved in a driver module where the module has to pass
commands to these drivers to check if they are attached to my device

I used the same method that I use to do it on an application open,
ioctl, close functions
But I get an error saying
Implicit declaration of function 'open'
Implicit declaration of function 'ioctl'
Implicit declaration of function 'close'
In what headers are they put-up?

I am using kernel 2.4 so I found no prototype for sys_open, sys_ioctl,
and sys_close

Suggest me as to what are the methods to access to other driver and
which is the best path.

Thanks

Mahesh