internal/poll: advance file position in windows sendfile

Some versions of Windows (Windows 10 1803) do not set file position after TransmitFile completes. So just use Seek to set file position before returning from sendfile. Fixes golang#25722 Change-Id: I7a49be10304b5db19dda707b13ac93d338aeb190 Reviewed-on: https://go-review.googlesource.com/131976 Reviewed-by: Brad Fitzpatrick <[email protected]> Reviewed-by: Ian Lance Taylor <[email protected]> Reviewed-by: Yasuhiro MATSUMOTO <[email protected]> Run-TryBot: Brad Fitzpatrick <[email protected]> TryBot-Result: Gobot Gobot <[email protected]>
fancybits · Sep 19, 2018 · a6bb6be · a6bb6be
1 parent f2113d9
commit a6bb6be
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/src/internal/poll/sendfile_windows.go b/src/internal/poll/sendfile_windows.go
@@ -38,5 +38,11 @@ func SendFile(fd *FD, src syscall.Handle, n int64) (int64, error) {
 	done, err := wsrv.ExecIO(o, func(o *operation) error {
 		return syscall.TransmitFile(o.fd.Sysfd, o.handle, o.qty, 0, &o.o, nil, syscall.TF_WRITE_BEHIND)
 	})
+	if err == nil {
+		// Some versions of Windows (Windows 10 1803) do not set
+		// file position after TransmitFile completes.
+		// So just use Seek to set file position.
+		_, err = syscall.Seek(o.handle, curpos+int64(done), 0)
+	}
 	return int64(done), err
 }