Linux Kernel Module Cheat

The ioctl system call is the best way to pass an arbitrary number of parameters to the kernel in a single go:

./ioctl.sh
echo $?

Outcome: the test passes:

Sources:

ioctl is one of the most important methods of communication with real device drivers, which often take several fields as input.

ioctl takes as input:

an integer request : it usually identifies what type of operation we want to do on this call
an untyped pointer to memory: can be anything, but is typically a pointer to a struct

The type of the struct often depends on the request input

This struct is defined on a uapi-style C header that is used both to compile the kernel module and the userland executable.

The fields of this struct can be thought of as arbitrary input parameters.

And the output is:

an integer return value. man ioctl documents:

Usually, on success zero is returned. A few ioctl() requests use the return value as an output parameter and return a nonnegative value on success. On error, -1 is returned, and errno is set appropriately.
the input pointer data may be overwritten to contain arbitrary output

Bibliography: