drivers: net: nsos: update unwatched file descriptor with poll()

zsock_poll_internal() iterates through all fds to call
ZFD_IOCTL_POLL_UPDATE on them. In cases when -EAGAIN is returned from one
of such syscalls (which happens for example for TLS sockets when in the
middle of a TLS handshake) whole fds array is iterated once again. This
means that ZFD_IOCTL_POLL_UPDATE can be called more than once for a single
preceding ZFD_IOCTL_POLL_PREPARE operation. This resulted in error in
nsos_adapt_poll_remove() call, which was not intended to be called twice.

In case ZFD_IOCTL_POLL_UPDATE is called second time, update 'revents' just
by calling poll() syscall on the host (Linux) side with 0 timeout.

Signed-off-by: Marcin Niestroj <m.niestroj@emb.dev>
3 files changed