Remove the direct dependency on libpcsclite

Instead, use a go library that communicates with pcscd over a socket.

Also update the changes introduced by @gravityblast since this PR's
inception

vendor/github.com/gballet/go-libpcsclite/msg.go

@@ -0,0 +1,78 @@
+// BSD 3-Clause License
+//
+// Copyright (c) 2019, Guillaume Ballet
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// * Redistributions of source code must retain the above copyright notice, this
+//   list of conditions and the following disclaimer.
+//
+// * Redistributions in binary form must reproduce the above copyright notice,
+//   this list of conditions and the following disclaimer in the documentation
+//   and/or other materials provided with the distribution.
+//
+// * Neither the name of the copyright holder nor the names of its
+//   contributors may be used to endorse or promote products derived from
+//   this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package pcsc
+
+import (
+	"encoding/binary"
+	"net"
+)
+
+/**
+ * @brief Wrapper for the MessageSend() function.
+ *
+ * Called by clients to send messages to the server.
+ * The parameters \p command and \p data are set in the \c sharedSegmentMsg
+ * struct in order to be sent.
+ *
+ * @param[in] command Command to be sent.
+ * @param[in] dwClientID Client socket handle.
+ * @param[in] size Size of the message (\p data).
+ * @param[in] data_void Data to be sent.
+ *
+ * @return Same error codes as MessageSend().
+ */
+func messageSendWithHeader(command uint32, conn net.Conn, data []byte) error {
+	/* Translate header into bytes */
+	msgData := make([]byte, 8+len(data))
+	binary.LittleEndian.PutUint32(msgData[4:], command)
+	binary.LittleEndian.PutUint32(msgData, uint32(len(data)))
+
+	/* Copy payload */
+	copy(msgData[8:], data)
+
+	_, err := conn.Write(msgData)
+	return err
+}
+
+// ClientSetupSession prepares a communication channel for the client to talk to the server.
+// This is called by the application to create a socket for local IPC with the
+// server. The socket is associated to the file \c PCSCLITE_CSOCK_NAME.
+/*
+ * @param[out] pdwClientID Client Connection ID.
+ *
+ * @retval 0 Success.
+ * @retval -1 Can not create the socket.
+ * @retval -1 The socket can not open a connection.
+ * @retval -1 Can not set the socket to non-blocking.
+ */
+func clientSetupSession() (net.Conn, error) {
+	return net.Dial("unix", PCSCDSockName)
+}