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 | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)
diff --git a/block/file-posix.c b/block/file-posix.c
index 666d3e7504..6473f84db8 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -1386,17 +1386,50 @@ static int handle_aiocb_flush(void *opaque)
#ifdef CONFIG_PREADV
static bool preadv_present = true;
+static bool preadv_checked;
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 (unlikely(!preadv_checked)) {
+ if (__builtin_available(macOS 11, iOS 14, watchOS 7, tvOS 14, *)) {
+ preadv_checked = true;
+ } else {
+ preadv_present = false;
+ return -ENOSYS;
+ }
+ }
+ /* Now we suppress the availability warning since we use the cached check
*/
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wunguarded-availability-new"
+ return preadv(fd, iov, nr_iov, offset);
+#pragma clang diagnostic pop
+#else /* CONFIG_DARWIN */
return preadv(fd, iov, nr_iov, offset);
+#endif
}
static ssize_t
qemu_pwritev(int fd, const struct iovec *iov, int nr_iov, off_t offset)
{
+#ifdef CONFIG_DARWIN /* preadv introduced in macOS 11 */
+ if (unlikely(!preadv_checked)) {
+ if (__builtin_available(macOS 11, iOS 14, watchOS 7, tvOS 14, *)) {
+ preadv_checked = true;
+ } else {
+ preadv_present = false;
+ return -ENOSYS;
+ }
+ }
+ /* Now we suppress the availability warning since we use the cached check
*/
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wunguarded-availability-new"
+ return pwritev(fd, iov, nr_iov, offset);
+#pragma clang diagnostic pop
+#else /* CONFIG_DARWIN */
return pwritev(fd, iov, nr_iov, offset);
+#endif
}
#else
--
2.28.0
