fileno() Does Not Check for NULL

[Joel Sherrill]

Hi

In looking at Coverity issues, we are seeing that calls to fileno() are
getting flagged as potential NULL dereferences. Looking at the POSIX
definition, it seems that it should return an -1/EBADF because NULL isn't a
valid stream.

https://pubs.opengroup.org/onlinepubs/9699919799/functions/fileno.html

I know there is a pattern of not having NULL checks assuming that the
environment would catch the fault. But in the embedded environments newlib
is used in, there isn't anything to catch the fault.

I don't want to add application code to check for a NULL before calling a
standard method that isn't robustly checking its arguments.

I don't know if it would address the Coverity issue but would adding the
nonnull attribute on more methods be acceptable and help? It is defined and
used in a few places now.

What's the right approach to addressing this?

Thanks.

--joel