check strtol/strtoul/strtoull results

check strtol/strtoul/strtoull results

The strto* family of functions may fail if the input string contains
a number which is too large for the designated data type. In such
cases, errno is set to ERANGE. Check for this error condition and if
subsequent casts would truncate the value.

Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Link: https://github.com/kmod-project/kmod/pull/357
Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>