lib: posix: Implement generic file descriptor table

The table allows to wrap read/write (i.e. POSIX-compatible) semantics
of any I/O object in POSIX-compatible fd (file descriptor) handling.
Intended I/O objects include files, sockets, special devices, etc.

The table table itself consists of (underlying obj*, function table*)
pairs, where function table provides entries for read(), write, and
generalized ioctl(), where generalized ioctl handles all other
operations, up to and including closing of the underlying I/O object.

Fixes: #7405

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
4 files changed