On 12.08.2012 01:24, Peter Maydell wrote:
> POSIX allows sendmsg() and recvmsg() to fail EMSGSIZE if passed a zero
> msg.msg_iovlen (in particular the MacOS X implementation will do this).
> Handle the case where iov_send_recv() is passed a zero byte count
> explicitly, to avoid accidentally depending on the OS to treat zero
> msg_iovlen as a no-op.
>
> Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
> ---
> This is what was causing 'make check' to fail on MacOS X.
> The other option was to declare that a zero bytecount was illegal, I guess.
Acked-by: Michael Tokarev <m...@tls.msk.ru>
Kevin, does this fix the test-iov failure you're seeing on one of
the build bots?
Thank you!
/mjt
> iov.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/iov.c b/iov.c
> index b333061..60705c7 100644
> --- a/iov.c
> +++ b/iov.c
> @@ -146,6 +146,13 @@ ssize_t iov_send_recv(int sockfd, struct iovec *iov,
> unsigned iov_cnt,
> {
> ssize_t ret;
> unsigned si, ei; /* start and end indexes */
> + if (bytes == 0) {
> + /* Catch the do-nothing case early, as otherwise we will pass an
> + * empty iovec to sendmsg/recvmsg(), and not all implementations
> + * accept this.
> + */
> + return 0;
> + }
>
> /* Find the start position, skipping `offset' bytes:
> * first, skip all full-sized vector elements, */
