El Mon, Apr 09, 2007 at 01:10:36AM -0500 Neo Jia ha dit:
> I understand that the system call will use $eax to pass the return
> value to user space application. But if we have more information
> (data) to pass, are we going to pass a pointer stored in $eax also
> instead of a simple value?
>
> Is there any other ways to pass information from kernel space to user
> space application?
the syscall interface can have a pointer as parameter that represents
a buffer to be filled in kernel space (the read() syscall is an
example). to copy data between kernel and userspace one would use the
functions copy_from_user(), copy_to_user(), get_user() and put_user().
--
Matthias Kaehlcke
Linux Application Developer
Barcelona
Anyone who has never made a mistake has never tried anything new
(Albert Einstein)
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