Serial backend fixes

compat.c

@@ -410,6 +410,14 @@ struct iio_context * iio_context_clone(const struct iio_context *old_ctx)
 	uri = IIO_CALL(iio_attr_get_static_value)(attr);
 	params = IIO_CALL(iio_context_get_params)(old_ctx);
 
+	if (strncmp(uri, "local:", sizeof("local:") - 1)
+	    && strncmp(uri, "ip:", sizeof("ip:") - 1)) {
+		/* The .clone callback was only implemented by the local
+		 * and network backends in Libiio <= v0.25. */
+		err = -ENOSYS;
+		goto err_set_errno;
+	}
+
 	ctx = IIO_CALL(iio_create_context)(params, uri);
 	err = iio_err(ctx);
 	if (err)

iiod-responder.c

@@ -240,12 +240,14 @@ static int iiod_responder_reader_thrd(void *d)
 {
 	struct iiod_responder *priv = d;
 	struct iiod_command cmd;
-	struct iiod_buf cmd_buf;
+	struct iiod_buf cmd_buf, ok_buf;
 	struct iiod_io *io;
 	ssize_t ret = 0;
 
 	cmd_buf.ptr = &cmd;
 	cmd_buf.size = sizeof(cmd);
+	ok_buf.ptr = "0\r\n";
+	ok_buf.size = 3;
 
 	iio_mutex_lock(priv->lock);
 
@@ -254,6 +256,18 @@ static int iiod_responder_reader_thrd(void *d)
 
 		ret = iiod_rw_all(priv, NULL, &cmd_buf, 1, sizeof(cmd), true);
 
+		if (!strncmp((char *)&cmd, "BINARY\r\n", 8)) {
+			/* If we receive again the "BINARY\r\n" string, send a
+			 * return code of zero and continue as usual.
+			 * This can happen with the serial backend when the
+			 * client disconnects and a new client appears.
+			 * Conveniently, the string is exactly 8 bytes, which is
+			 * the size of a iio_command. */
+
+			iiod_rw_all(priv, NULL, &ok_buf, 1, ok_buf.size, false);
+			continue;
+		}
+
 		iio_mutex_lock(priv->lock);
 		if (ret <= 0)
 			break;

serial.c

@@ -13,18 +13,25 @@
 #include <iio/iio-lock.h>
 #include <iio/iiod-client.h>
 
+#include <ctype.h>
 #include <errno.h>
 #include <libserialport.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <ctype.h>
+#ifdef _WIN32
+#include <Windows.h>
+#else
+#include <time.h>
+#endif
 
 struct iio_context_pdata {
 	struct sp_port *port;
 	struct iiod_client *iiod_client;
 
 	struct iio_context_params params;
+
+	bool shutdown;
 };
 
 struct iio_buffer_pdata {
@@ -145,21 +152,44 @@ static ssize_t serial_write_data(struct iiod_client_pdata *io_data,
 	return ret;
 }
 
+void sleep_one_ms(void)
+{
+#ifdef _WIN32
+	Sleep(1);
+#else
+	const struct timespec ts = {
+		/* One millisecond */
+		.tv_nsec = 1 * 1000 * 1000,
+	};
+
+	nanosleep(&ts, NULL);
+#endif
+}
+
 static ssize_t serial_read_data(struct iiod_client_pdata *io_data,
 				char *buf, size_t len, unsigned int timeout_ms)
 {
 	struct iio_context_pdata *pdata = (struct iio_context_pdata *) io_data;
+	long long time_left_ms = (long long)timeout_ms;
 	enum sp_return sp_ret;
-	ssize_t ret;
+	ssize_t ret = 0;
 
-	sp_ret = sp_blocking_read_next(pdata->port, buf, len, timeout_ms);
-	ret = (ssize_t) libserialport_to_errno(sp_ret);
+	while (true) {
+		if (timeout_ms && time_left_ms <= 0)
+			break;
+
+		sp_ret = sp_nonblocking_read(pdata->port, buf, len);
+		ret = (ssize_t) libserialport_to_errno(sp_ret);
+		if (ret || pdata->shutdown)
+			break;
 
-	prm_dbg(&pdata->params, "Read returned %li: %.*s\n",
-		(long) ret, (int) ret, buf);
+		sleep_one_ms();
+		time_left_ms--;
+	}
 
 	if (ret == 0) {
-		prm_err(&pdata->params, "sp_blocking_read_next has timed out\n");
+		if (!pdata->shutdown)
+			prm_err(&pdata->params, "serial_read_data has timed out\n");
 		return -ETIMEDOUT;
 	}
 
@@ -170,6 +200,8 @@ static void serial_shutdown(struct iio_context *ctx)
 {
 	struct iio_context_pdata *ctx_pdata = iio_context_get_pdata(ctx);
 
+	ctx_pdata->shutdown = true;
+
 	iiod_client_destroy(ctx_pdata->iiod_client);
 	sp_close(ctx_pdata->port);
 	sp_free_port(ctx_pdata->port);
@@ -230,6 +262,18 @@ static int serial_enable_buffer(struct iio_buffer_pdata *buf,
 	return iiod_client_enable_buffer(buf->pdata, nb_samples, enable);
 }
 
+static ssize_t
+serial_readbuf(struct iio_buffer_pdata *buf, void *dst, size_t len)
+{
+	return iiod_client_readbuf(buf->pdata, dst, len);
+}
+
+static ssize_t
+serial_writebuf(struct iio_buffer_pdata *buf, const void *src, size_t len)
+{
+	return iiod_client_writebuf(buf->pdata, src, len);
+}
+
 static struct iio_block_pdata *
 serial_create_block(struct iio_buffer_pdata *buf, size_t size, void **data)
 {
@@ -257,6 +301,9 @@ static const struct iio_backend_ops serial_ops = {
 	.free_buffer = serial_free_buffer,
 	.enable_buffer = serial_enable_buffer,
 
+	.readbuf = serial_readbuf,
+	.writebuf = serial_writebuf,
+
 	.create_block = serial_create_block,
 	.free_block = iiod_client_free_block,
 	.enqueue_block = iiod_client_enqueue_block,