On 11/9/20 12:24 AM, Joelle van Dyne wrote:
> macOS 11/iOS 14 added preadv/pwritev APIs. Due to weak linking, configure
> will succeed with CONFIG_PREADV even when targeting a lower OS version. We
> therefore need to check at run time if we can actually use these APIs.
>
> Signed-off-by: Joelle van Dyne <j...@getutm.app>
> ---
> block/file-posix.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/block/file-posix.c b/block/file-posix.c
> index d83219df55..a9d69746a0 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -1394,12 +1394,24 @@ static bool preadv_present = true;
> static ssize_t
> qemu_preadv(int fd, const struct iovec *iov, int nr_iov, off_t offset)
> {
> +#ifdef CONFIG_DARWIN /* preadv introduced in macOS 11 */
> + if (!__builtin_available(macOS 11, iOS 14, watchOS 7, tvOS 14, *)) {
Can we change the CONFIG_PREADV ifdef'ry to run this check once
on macOS 11?
> + preadv_present = false;
> + return -ENOSYS;
> + } else
> +#endif
> return preadv(fd, iov, nr_iov, offset);
> }
>
> static ssize_t
> qemu_pwritev(int fd, const struct iovec *iov, int nr_iov, off_t offset)
> {
> +#ifdef CONFIG_DARWIN /* pwritev introduced in macOS 11 */
> + if (!__builtin_available(macOS 11, iOS 14, watchOS 7, tvOS 14, *)) {
> + preadv_present = false;
> + return -ENOSYS;
> + } else
> +#endif
> return pwritev(fd, iov, nr_iov, offset);
> }
>
>
