[Valgrind-users] Syscall/ioctl wrappers

[Subhashish P. <sp...@gm...>]

Hello!

I posted this on valgrind-devel mailing list but got no reply so i'm
posting it here.

I have some new questions that I'd like to understand about
unimplemented system calls.

The eject.c example provided here at http://leapster.org/linux/cdrom/
will compile successfuly
with a #include <stdlib.h>. Then when run it under as "valgrind
./eject', it still reports:

==6212== Command: ./eject
==6212==
==6212== Warning: noted but unhandled ioctl 0x5309 with no size/direction hints
==6212==    This could cause spurious value errors to appear.
==6212==    See README_MISSING_SYSCALL_OR_IOCTL for guidance on
writing a proper wrapper.

Why would that be? (since ioctls are wrapped in
coregrind/m_syswrap/syswrap-linux.c)

What is this "ioctl 0x5309 with no size/redirection hints" and how
could that be solved
by PRE or POST functions?

Or specifically, I couldn't understand the 0x5309 operation code
context as explained in this post on this mailing list below:
<http://valgrind.10908.n7.nabble.com/noted-but-unhandled-ioctl-0xae03-with-no-size-direction-hints-tp38957p38959.html>

How can we use that opcode to write wrappers?

Regards,
Subhashish Pradhan