Workaround for go unix package not wrapping pselect() on darwin

tools/utils/select_posix.go

@@ -0,0 +1,29 @@
+//go:build !darwin
+
+package utils
+
+import (
+	"os"
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+func Select(nfd int, r *unix.FdSet, w *unix.FdSet, e *unix.FdSet, timeout time.Duration) (n int, err error) {
+	deadline := time.Now().Add(timeout)
+	for {
+		t := deadline.Sub(time.Now())
+		if t < 0 {
+			t = 0
+		}
+		ts := NsecToTimespec(t)
+		q, qerr := unix.Pselect(nfd, r, w, w, &ts, nil)
+		if qerr == unix.EINTR {
+			if time.Now().After(deadline) {
+				return 0, os.ErrDeadlineExceeded
+			}
+			continue
+		}
+		return q, qerr
+	}
+}

tools/utils/select_without_pselect.go

@@ -0,0 +1,31 @@
+//go:build darwin
+
+package utils
+
+import (
+	"os"
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+// Go unix does not wrap pselect on darwin
+
+func Select(nfd int, r *unix.FdSet, w *unix.FdSet, e *unix.FdSet, timeout time.Duration) (n int, err error) {
+	deadline := time.Now().Add(timeout)
+	for {
+		t := deadline.Sub(time.Now())
+		if t < 0 {
+			t = 0
+		}
+		ts := NsecToTimeval(t)
+		q, qerr := unix.Select(nfd, r, w, w, &ts)
+		if qerr == unix.EINTR {
+			if time.Now().After(deadline) {
+				return 0, os.ErrDeadlineExceeded
+			}
+			continue
+		}
+		return q, qerr
+	}
+}