internal/poll: don't add non-sockets to runtime poller

Updates #21172

Change-Id: I0fec6e645328bbc85f3e47f4f71dd8d1d68c75ab
Reviewed-on: https://go-review.googlesource.com/52551
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

diff --git a/src/internal/poll/fd_windows.go b/src/internal/poll/fd_windows.go
index 9f40886d08b074ba47cd9f15c466547a891455d3..655f9348c62236f534a2c67aaff68548800b8b87 100644 (file)
--- a/src/internal/poll/fd_windows.go
+++ b/src/internal/poll/fd_windows.go
@@ -154,6 +154,10 @@ func (s *ioSrv) ProcessRemoteIO() {
 // is available. Alternatively, it passes the request onto
 // runtime netpoll and waits for completion or cancels request.
 func (s *ioSrv) ExecIO(o *operation, submit func(o *operation) error) (int, error) {
+       if o.fd.pd.runtimeCtx == 0 {
+               return 0, errors.New("internal error: polling on unsupported descriptor type")
+       }
+
        if !canCancelIO {
                onceStartServer.Do(startServer)
        }
@@ -315,8 +319,21 @@ func (fd *FD) Init(net string) (string, error) {
                return "", errors.New("internal error: unknown network type " + net)
        }
 
-       if err := fd.pd.init(fd); err != nil {
-               return "", err
+       if !fd.isFile && !fd.isConsole && !fd.isDir {
+               // Only call init for a network socket.
+               // This means that we don't add files to the runtime poller.
+               // Adding files to the runtime poller can confuse matters
+               // if the user is doing their own overlapped I/O.
+               // See issue #21172.
+               //
+               // In general the code below avoids calling the ExecIO
+               // method for non-network sockets. If some method does
+               // somehow call ExecIO, then ExecIO, and therefore the
+               // calling method, will return an error, because
+               // fd.pd.runtimeCtx will be 0.
+               if err := fd.pd.init(fd); err != nil {
+                       return "", err
+               }
        }
        if hasLoadSetFileCompletionNotificationModes {
                // We do not use events, so we can skip them always.