diff --git a/cmd/faucet/faucet.go b/cmd/faucet/faucet.go index 79a84fd24e..a0fc28c0d4 100644 --- a/cmd/faucet/faucet.go +++ b/cmd/faucet/faucet.go @@ -213,7 +213,7 @@ type faucet struct { nonce uint64 // Current pending nonce of the faucet price *big.Int // Current gas price to issue funds with - conns []*websocket.Conn // Currently live websocket connections + conns []*wsConn // Currently live websocket connections timeouts map[string]time.Time // History of users and their funding timeouts reqs []*request // Currently pending funding requests update chan struct{} // Channel to signal request updates @@ -221,6 +221,13 @@ type faucet struct { lock sync.RWMutex // Lock protecting the faucet's internals } +// wsConn wraps a websocket connection with a write mutex as the underlying +// websocket library does not synchronize access to the stream. +type wsConn struct { + conn *websocket.Conn + wlock sync.Mutex +} + func newFaucet(genesis *core.Genesis, port int, enodes []*discv5.Node, network uint64, stats string, ks *keystore.KeyStore, index []byte) (*faucet, error) { // Assemble the raw devp2p protocol stack stack, err := node.New(&node.Config{ @@ -321,13 +328,14 @@ func (f *faucet) apiHandler(w http.ResponseWriter, r *http.Request) { defer conn.Close() f.lock.Lock() - f.conns = append(f.conns, conn) + wsconn := &wsConn{conn: conn} + f.conns = append(f.conns, wsconn) f.lock.Unlock() defer func() { f.lock.Lock() for i, c := range f.conns { - if c == conn { + if c.conn == conn { f.conns = append(f.conns[:i], f.conns[i+1:]...) break } @@ -355,7 +363,7 @@ func (f *faucet) apiHandler(w http.ResponseWriter, r *http.Request) { if head == nil || balance == nil { // Report the faucet offline until initial stats are ready //lint:ignore ST1005 This error is to be displayed in the browser - if err = sendError(conn, errors.New("Faucet offline")); err != nil { + if err = sendError(wsconn, errors.New("Faucet offline")); err != nil { log.Warn("Failed to send faucet error to client", "err", err) return } @@ -366,7 +374,7 @@ func (f *faucet) apiHandler(w http.ResponseWriter, r *http.Request) { f.lock.RLock() reqs := f.reqs f.lock.RUnlock() - if err = send(conn, map[string]interface{}{ + if err = send(wsconn, map[string]interface{}{ "funds": new(big.Int).Div(balance, ether), "funded": nonce, "peers": f.stack.Server().PeerCount(), @@ -375,7 +383,7 @@ func (f *faucet) apiHandler(w http.ResponseWriter, r *http.Request) { log.Warn("Failed to send initial stats to client", "err", err) return } - if err = send(conn, head, 3*time.Second); err != nil { + if err = send(wsconn, head, 3*time.Second); err != nil { log.Warn("Failed to send initial header to client", "err", err) return } @@ -391,7 +399,7 @@ func (f *faucet) apiHandler(w http.ResponseWriter, r *http.Request) { return } if !*noauthFlag && !strings.HasPrefix(msg.URL, "https://twitter.com/") && !strings.HasPrefix(msg.URL, "https://www.facebook.com/") { - if err = sendError(conn, errors.New("URL doesn't link to supported services")); err != nil { + if err = sendError(wsconn, errors.New("URL doesn't link to supported services")); err != nil { log.Warn("Failed to send URL error to client", "err", err) return } @@ -399,7 +407,7 @@ func (f *faucet) apiHandler(w http.ResponseWriter, r *http.Request) { } if msg.Tier >= uint(*tiersFlag) { //lint:ignore ST1005 This error is to be displayed in the browser - if err = sendError(conn, errors.New("Invalid funding tier requested")); err != nil { + if err = sendError(wsconn, errors.New("Invalid funding tier requested")); err != nil { log.Warn("Failed to send tier error to client", "err", err) return } @@ -415,7 +423,7 @@ func (f *faucet) apiHandler(w http.ResponseWriter, r *http.Request) { res, err := http.PostForm("https://www.google.com/recaptcha/api/siteverify", form) if err != nil { - if err = sendError(conn, err); err != nil { + if err = sendError(wsconn, err); err != nil { log.Warn("Failed to send captcha post error to client", "err", err) return } @@ -428,7 +436,7 @@ func (f *faucet) apiHandler(w http.ResponseWriter, r *http.Request) { err = json.NewDecoder(res.Body).Decode(&result) res.Body.Close() if err != nil { - if err = sendError(conn, err); err != nil { + if err = sendError(wsconn, err); err != nil { log.Warn("Failed to send captcha decode error to client", "err", err) return } @@ -437,7 +445,7 @@ func (f *faucet) apiHandler(w http.ResponseWriter, r *http.Request) { if !result.Success { log.Warn("Captcha verification failed", "err", string(result.Errors)) //lint:ignore ST1005 it's funny and the robot won't mind - if err = sendError(conn, errors.New("Beep-bop, you're a robot!")); err != nil { + if err = sendError(wsconn, errors.New("Beep-bop, you're a robot!")); err != nil { log.Warn("Failed to send captcha failure to client", "err", err) return } @@ -465,7 +473,7 @@ func (f *faucet) apiHandler(w http.ResponseWriter, r *http.Request) { err = errors.New("Something funky happened, please open an issue at https://github.com/ethereum/go-ethereum/issues") } if err != nil { - if err = sendError(conn, err); err != nil { + if err = sendError(wsconn, err); err != nil { log.Warn("Failed to send prefix error to client", "err", err) return } @@ -489,7 +497,7 @@ func (f *faucet) apiHandler(w http.ResponseWriter, r *http.Request) { signed, err := f.keystore.SignTx(f.account, tx, f.config.ChainID) if err != nil { f.lock.Unlock() - if err = sendError(conn, err); err != nil { + if err = sendError(wsconn, err); err != nil { log.Warn("Failed to send transaction creation error to client", "err", err) return } @@ -498,7 +506,7 @@ func (f *faucet) apiHandler(w http.ResponseWriter, r *http.Request) { // Submit the transaction and mark as funded if successful if err := f.client.SendTransaction(context.Background(), signed); err != nil { f.lock.Unlock() - if err = sendError(conn, err); err != nil { + if err = sendError(wsconn, err); err != nil { log.Warn("Failed to send transaction transmission error to client", "err", err) return } @@ -520,13 +528,13 @@ func (f *faucet) apiHandler(w http.ResponseWriter, r *http.Request) { // Send an error if too frequent funding, othewise a success if !fund { - if err = sendError(conn, fmt.Errorf("%s left until next allowance", common.PrettyDuration(time.Until(timeout)))); err != nil { // nolint: gosimple + if err = sendError(wsconn, fmt.Errorf("%s left until next allowance", common.PrettyDuration(time.Until(timeout)))); err != nil { // nolint: gosimple log.Warn("Failed to send funding error to client", "err", err) return } continue } - if err = sendSuccess(conn, fmt.Sprintf("Funding request accepted for %s into %s", username, address.Hex())); err != nil { + if err = sendSuccess(wsconn, fmt.Sprintf("Funding request accepted for %s into %s", username, address.Hex())); err != nil { log.Warn("Failed to send funding success to client", "err", err) return } @@ -619,12 +627,12 @@ func (f *faucet) loop() { "requests": f.reqs, }, time.Second); err != nil { log.Warn("Failed to send stats to client", "err", err) - conn.Close() + conn.conn.Close() continue } if err := send(conn, head, time.Second); err != nil { log.Warn("Failed to send header to client", "err", err) - conn.Close() + conn.conn.Close() } } f.lock.RUnlock() @@ -646,7 +654,7 @@ func (f *faucet) loop() { for _, conn := range f.conns { if err := send(conn, map[string]interface{}{"requests": f.reqs}, time.Second); err != nil { log.Warn("Failed to send requests to client", "err", err) - conn.Close() + conn.conn.Close() } } f.lock.RUnlock() @@ -656,23 +664,26 @@ func (f *faucet) loop() { // sends transmits a data packet to the remote end of the websocket, but also // setting a write deadline to prevent waiting forever on the node. -func send(conn *websocket.Conn, value interface{}, timeout time.Duration) error { +func send(conn *wsConn, value interface{}, timeout time.Duration) error { if timeout == 0 { timeout = 60 * time.Second } - conn.SetWriteDeadline(time.Now().Add(timeout)) - return conn.WriteJSON(value) + conn.wlock.Lock() + defer conn.wlock.Unlock() + + conn.conn.SetWriteDeadline(time.Now().Add(timeout)) + return conn.conn.WriteJSON(value) } // sendError transmits an error to the remote end of the websocket, also setting // the write deadline to 1 second to prevent waiting forever. -func sendError(conn *websocket.Conn, err error) error { +func sendError(conn *wsConn, err error) error { return send(conn, map[string]string{"error": err.Error()}, time.Second) } // sendSuccess transmits a success message to the remote end of the websocket, also // setting the write deadline to 1 second to prevent waiting forever. -func sendSuccess(conn *websocket.Conn, msg string) error { +func sendSuccess(conn *wsConn, msg string) error { return send(conn, map[string]string{"success": msg}, time.Second) }