Embedded libiio + libtinyiiod

CMakeLists.txt

@@ -243,6 +243,8 @@ if (ENABLE_IPV6)
 	endif()
 endif()
 
+option(WITH_EXTERNAL_BACKEND "Support external backend provided by the application" OFF)
+
 option(WITH_USB_BACKEND "Enable the libusb backend" ON)
 if (WITH_USB_BACKEND)
 	find_package(PkgConfig)
@@ -325,13 +327,11 @@ else()
 	message(STATUS "GCC ${CMAKE_COMPILER_IS_GNUCC}")
 endif()
 
+option(WITH_LIBTINYIIOD "Build libtinyiiod" OFF)
+
 IF(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
 	option(WITH_IIOD "Build the IIO Daemon" ON)
 	option(WITH_LOCAL_BACKEND "Enable the local backend" ON)
-
-	if (WITH_IIOD AND NOT WITH_LOCAL_BACKEND)
-		message(SEND_ERROR "IIOD can only be enabled if the local backend is enabled")
-	endif()
 endif()
 
 set(DOXYGEN_INPUT "${CMAKE_SOURCE_DIR}")
@@ -374,6 +374,10 @@ set(LIBIIO_VERSION ${VERSION}.g${LIBIIO_VERSION_GIT})
 file(WRITE ${CMAKE_BINARY_DIR}/.version ${LIBIIO_VERSION})
 
 if(WITH_LOCAL_BACKEND)
+	if (NO_THREADS)
+		message(SEND_ERROR "Local backend require threads.")
+	endif()
+
 	target_sources(iio PRIVATE local.c)
 
 	# Link with librt if present
@@ -578,7 +582,10 @@ elseif(NEED_LIBXML2)
 		"If you want to enable the XML backend, set WITH_XML_BACKEND=ON.")
 endif()
 
-if (WIN32)
+option(NO_THREADS "Build a thread-less Libiio library" OFF)
+if (NO_THREADS)
+	target_sources(iio PRIVATE lock-dummy.c)
+elseif (WIN32)
 	target_sources(iio PRIVATE lock-windows.c)
 else ()
 	if (NOT ANDROID)
@@ -594,9 +601,9 @@ else ()
 	target_sources(iio PRIVATE lock.c)
 endif()
 
-if (IIOD_CLIENT OR WITH_IIOD)
+if (IIOD_CLIENT OR WITH_IIOD OR WITH_LIBTINYIIOD)
 	add_library(iiod-responder STATIC iiod-responder.c)
-	target_include_directories(iiod-responder PRIVATE include)
+	target_include_directories(iiod-responder PRIVATE include ${CMAKE_BINARY_DIR})
 	set_target_properties(iiod-responder PROPERTIES POSITION_INDEPENDENT_CODE ON)
 
 	# Link against exported symbols of Libiio and not the
@@ -608,6 +615,10 @@ if (IIOD_CLIENT OR WITH_IIOD)
 endif()
 
 if (IIOD_CLIENT)
+	if (NO_THREADS)
+		message(SEND_ERROR "Backends using iiod-client require threads.")
+	endif()
+
 	target_sources(iio PRIVATE iiod-client.c)
 	target_link_libraries(iio PRIVATE iiod-responder)
 endif()
@@ -627,6 +638,10 @@ if(WITH_EXAMPLES)
 	add_subdirectory(examples)
 endif()
 if (WITH_IIOD)
+	if (NO_THREADS)
+		message(SEND_ERROR "IIOD require threads.")
+	endif()
+
 	if (NOT PTHREAD_LIBRARIES)
 		message(SEND_ERROR "IIOD requires pthread support.\n"
 			"If you want to disable IIOD, set WITH_IIOD=OFF.")
@@ -635,6 +650,10 @@ if (WITH_IIOD)
 	add_subdirectory(iiod)
 endif()
 
+if (WITH_LIBTINYIIOD)
+	add_subdirectory(tinyiiod)
+endif()
+
 if ((WITH_IIOD OR IIOD_CLIENT) AND NOT WITH_ZSTD)
 	message(WARNING "IIOD async. API requires ZSTD support, consider enabling it.\n"
 		"If you want to enable libzstd support, set WITH_ZSTD=ON.")
@@ -674,10 +693,12 @@ string(REPLACE ";" "," LIBIIO_SCAN_BACKENDS "${LIBIIO_SCAN_BACKENDS}")
 
 configure_file(iio-config.h.cmakein ${CMAKE_CURRENT_BINARY_DIR}/iio-config.h @ONLY)
 
+toggle_iio_feature("${NO_THREADS}" threadless)
 toggle_iio_feature("${LIBIIO_COMPAT}" compat)
 toggle_iio_feature("${WITH_XML_BACKEND}" xml)
 toggle_iio_feature("${WITH_ZSTD}" zstd)
 toggle_iio_feature("${WITH_NETWORK_BACKEND}" network)
+toggle_iio_feature("${WITH_EXTERNAL_BACKEND}" external)
 toggle_iio_feature("${HAVE_DNS_SD}" dns-sd)
 toggle_iio_feature("${HAVE_AVAHI}" avahi)
 toggle_iio_feature("${HAVE_BONJOUR}" bonjour)
@@ -690,6 +711,7 @@ toggle_iio_feature("${WITH_HWMON}" hwmon)
 toggle_iio_feature("${WITH_USB_BACKEND}" usb)
 toggle_iio_feature("${WITH_UTILS}" utils)
 toggle_iio_feature("${WITH_EXAMPLES}" examples)
+toggle_iio_feature("${WITH_LIBTINYIIOD}" libtinyiiod)
 toggle_iio_feature("${WITH_IIOD}" iiod)
 toggle_iio_feature("${WITH_MODULES}" modules)
 toggle_iio_feature("${WITH_USB_BACKEND_DYNAMIC}" usb-dynamic)

README_BUILD.md

@@ -72,6 +72,7 @@ Cmake Options          | Default | Depends on    | Description
 `WITH_SERIAL_BACKEND_DYNAMIC` |  ON | Modules + serial backend | Compile the serial backend as a module |
 `WITH_NETWORK_BACKEND` |  ON |               | Supports TCP/IP                  |
 `WITH_NETWORK_BACKEND_DYNAMIC` |  ON | Modules + network backend | Compile the network backend as a module |
+`WITH_EXTERNAL_BACKEND` | OFF | | Support external backend provided by the application |
 `HAVE_DNS_SD`          |  ON | Networking    | Enable DNS-SD (ZeroConf) support |
 `ENABLE_IPV6`          |  ON | Networking    | Define if you want to enable IPv6 support |
 `WITH_LOCAL_BACKEND`   |  ON | Linux         | Enables local support with iiod  |
@@ -109,6 +110,7 @@ Cmake Options       | Default | Description                                    |
 `WITH_IIOD_SERIAL`  |  ON | Add serial (UART) support                            |
 `WITH_IIOD_USBD`    |  ON | Add support for USB through FunctionFS within IIOD   |
 `WITH_IIOD_V0_COMPAT` |  ON | Add support for Libiio v0.x protocol and clients |
+`WITH_LIBTINYIIOD`  | OFF | Build libtinyiiod                                    |
 `WITH_AIO`          |  ON | Build IIOD with async. I/O support                   |
 `WITH_SYSTEMD`      | OFF | Enable installation of systemd service file for iiod |
 `SYSTEMD_UNIT_INSTALL_DIR`  | /lib/systemd/system | default install path for systemd unit files |

context.c

@@ -396,6 +396,7 @@ const struct iio_backend * const iio_backends[] = {
 	IF_ENABLED(WITH_USB_BACKEND && !WITH_USB_BACKEND_DYNAMIC,
 		   &iio_usb_backend),
 	IF_ENABLED(WITH_XML_BACKEND, &iio_xml_backend),
+	IF_ENABLED(WITH_EXTERNAL_BACKEND, &iio_external_backend),
 };
 const unsigned int iio_backends_size = ARRAY_SIZE(iio_backends);
 

dns_sd.h

@@ -24,7 +24,6 @@
 
 /* IPv6 Max = 4*8 + 7 + 1 for '%' + interface length */
 #define DNS_SD_ADDRESS_STR_MAX (40 + IF_NAMESIZE)
-#define FQDN_LEN (255)              /* RFC 1035 */
 
 /* MacOS doesn't include ENOMEDIUM (No medium found) like Linux does */
 #ifndef ENOMEDIUM

dns_sd_bonjour.c

@@ -8,6 +8,7 @@
  */
 
 #include "dns_sd.h"
+#include "network.h" // for FQDN_LEN
 
 #include <arpa/inet.h>
 #include <netinet/in.h>

iio-config.h.cmakein

@@ -21,6 +21,7 @@
 #cmakedefine01 WITH_NETWORK_BACKEND
 #cmakedefine01 WITH_USB_BACKEND
 #cmakedefine01 WITH_SERIAL_BACKEND
+#cmakedefine01 WITH_EXTERNAL_BACKEND
 
 #cmakedefine01 WITH_MODULES
 #cmakedefine01 WITH_NETWORK_BACKEND_DYNAMIC
@@ -40,6 +41,7 @@
 #cmakedefine01 HAVE_DNS_SD
 #cmakedefine01 HAVE_AVAHI
 #cmakedefine01 WITH_ZSTD
+#cmakedefine01 NO_THREADS
 
 #cmakedefine HAS_PIPE2
 #cmakedefine HAS_STRDUP
@@ -49,7 +51,6 @@
 #cmakedefine HAS_NEWLOCALE
 #cmakedefine HAS_PTHREAD_SETNAME_NP
 #cmakedefine HAVE_IPV6
-#cmakedefine NO_THREADS
 
 #define IF_ENABLED(cfg, ptr) ((cfg) ? (ptr) : NULL)
 

iiod-client.c

@@ -440,25 +440,6 @@ int iiod_client_set_trigger(struct iiod_client *client,
 	return ret;
 }
 
-int iiod_client_set_kernel_buffers_count(struct iiod_client *client,
-					 const struct iio_device *dev,
-					 unsigned int nb_blocks)
-{
-	int ret;
-	char buf[1024];
-
-	if (iiod_client_uses_binary_interface(client))
-		return -ENOSYS;
-
-	iio_snprintf(buf, sizeof(buf), "SET %s BUFFERS_COUNT %u\r\n",
-			iio_device_get_id(dev), nb_blocks);
-
-	iio_mutex_lock(client->lock);
-	ret = iiod_client_exec_command(client, buf);
-	iio_mutex_unlock(client->lock);
-	return ret;
-}
-
 static unsigned int calculate_remote_timeout(unsigned int timeout_ms)
 {
 	/* XXX(pcercuei): We currently hardcode timeout / 2 for the backend used
@@ -963,13 +944,16 @@ iiod_client_create_context_private_new(struct iiod_client *client,
 	struct iio_context *ctx = NULL;
 	unsigned long long len;
 	char *xml_zstd, *xml;
+	bool is_zstd;
 	int ret;
 
-	xml = malloc(xml_len);
+	xml = malloc(xml_len + uri_len);
 	if (!xml)
 		return iio_ptr(-ENOMEM);
 
-	ret = iiod_client_send_print(client, xml, xml_len);
+	memcpy(xml, "xml:", uri_len);
+
+	ret = iiod_client_send_print(client, &xml[uri_len], xml_len);
 	if (ret < 0) {
 		prm_perror(client->params, -ret,
 			   "Unable to send PRINT command");
@@ -978,37 +962,42 @@ iiod_client_create_context_private_new(struct iiod_client *client,
 
 	xml_len = ret;
 
+	is_zstd = strncmp(xml, "xml:<?xml", sizeof("xml:<?xml") - 1) != 0;
+	if (is_zstd)
+		prm_dbg(client->params, "Received ZSTD-compressed XML string.\n");
+	else
+		prm_dbg(client->params, "Received uncompressed XML string.\n");
 
-	prm_dbg(client->params, "Received ZSTD-compressed XML string.\n");
-
-	len = ZSTD_getFrameContentSize(xml, xml_len);
-	if (len == ZSTD_CONTENTSIZE_UNKNOWN ||
-	    len == ZSTD_CONTENTSIZE_ERROR) {
-		ret = -EIO;
-		goto out_free_xml;
-	}
+	if (is_zstd) {
+		len = ZSTD_getFrameContentSize(&xml[uri_len], xml_len);
+		if (len == ZSTD_CONTENTSIZE_UNKNOWN ||
+		    len == ZSTD_CONTENTSIZE_ERROR) {
+			ret = -EIO;
+			goto out_free_xml;
+		}
 
-	xml_zstd = malloc(uri_len + len + 1);
-	if (!xml_zstd) {
-		ret = -ENOMEM;
-		goto out_free_xml;
-	}
+		xml_zstd = malloc(uri_len + len + 1);
+		if (!xml_zstd) {
+			ret = -ENOMEM;
+			goto out_free_xml;
+		}
 
-	xml_len = ZSTD_decompress(xml_zstd + uri_len, len, xml, xml_len);
-	if (ZSTD_isError(xml_len)) {
-		prm_err(client->params, "Unable to decompress ZSTD data: %s\n",
-			ZSTD_getErrorName(xml_len));
-		ret = -EIO;
-		free(xml_zstd);
-		goto out_free_xml;
-	}
+		xml_len = ZSTD_decompress(&xml_zstd[uri_len], len, &xml[uri_len], xml_len);
+		if (ZSTD_isError(xml_len)) {
+			prm_err(client->params, "Unable to decompress ZSTD data: %s\n",
+				ZSTD_getErrorName(xml_len));
+			ret = -EIO;
+			free(xml_zstd);
+			goto out_free_xml;
+		}
 
-	memcpy(xml_zstd, "xml:", uri_len);
-	xml_zstd[uri_len + xml_len] = '\0';
+		memcpy(xml_zstd, "xml:", uri_len);
+		xml_zstd[uri_len + xml_len] = '\0';
 
-	/* Free compressed data, make "xml" point to uncompressed data */
-	free(xml);
-	xml = xml_zstd;
+		/* Free compressed data, make "xml" point to uncompressed data */
+		free(xml);
+		xml = xml_zstd;
+	}
 
 	prm_dbg(client->params, "Creating context\n");
 

iiod-responder.c

@@ -7,6 +7,7 @@
  */
 
 #include "iiod-responder.h"
+#include "iio-config.h"
 
 #include <errno.h>
 #include <iio/iio.h>
@@ -74,7 +75,6 @@ struct iiod_responder {
 	struct iio_mutex *lock;
 	struct iio_thrd *read_thrd;
 	struct iio_task *write_task;
-	struct iio_thrd *write_thrd;
 
 	bool thrd_stop;
 	int thrd_err_code;
@@ -237,9 +237,8 @@ static void iiod_responder_cancel_responses(struct iiod_responder *priv)
 	}
 }
 
-static int iiod_responder_reader_thrd(void *d)
+static int iiod_responder_reader_worker(struct iiod_responder *priv)
 {
-	struct iiod_responder *priv = d;
 	struct iiod_command cmd;
 	struct iiod_buf cmd_buf, ok_buf;
 	struct iiod_io *io;
@@ -342,6 +341,11 @@ static int iiod_responder_reader_thrd(void *d)
 	return (int) ret;
 }
 
+static int iiod_responder_reader_thrd(void *d)
+{
+	return iiod_responder_reader_worker(d);
+}
+
 static int iiod_responder_write(void *p, void *elm)
 {
 	struct iiod_responder *priv = p;
@@ -668,11 +672,13 @@ iiod_responder_create(const struct iiod_responder_ops *ops, void *d)
 	if (err)
 		goto err_free_io;
 
-	priv->read_thrd = iio_thrd_create(iiod_responder_reader_thrd, priv,
-					  "iiod-responder-reader-thd");
-	err = iio_err(priv->read_thrd);
-	if (err)
-		goto err_free_write_task;
+	if (!NO_THREADS) {
+		priv->read_thrd = iio_thrd_create(iiod_responder_reader_thrd, priv,
+						  "iiod-responder-reader-thd");
+		err = iio_err(priv->read_thrd);
+		if (err)
+			goto err_free_write_task;
+	}
 
 	iio_task_start(priv->write_task);
 
@@ -689,9 +695,14 @@ iiod_responder_create(const struct iiod_responder_ops *ops, void *d)
 	return iio_ptr(err);
 }
 
-void iiod_responder_destroy(struct iiod_responder *priv)
+void iiod_responder_stop(struct iiod_responder *priv)
 {
 	priv->thrd_stop = true;
+}
+
+void iiod_responder_destroy(struct iiod_responder *priv)
+{
+	iiod_responder_stop(priv);
 	iiod_responder_wait_done(priv);
 
 	iio_task_destroy(priv->write_task);
@@ -703,9 +714,12 @@ void iiod_responder_destroy(struct iiod_responder *priv)
 
 void iiod_responder_wait_done(struct iiod_responder *priv)
 {
-	if (priv->read_thrd) {
-		iio_thrd_join_and_destroy(priv->read_thrd);
+	if (!NO_THREADS) {
+		if (priv->read_thrd)
+			iio_thrd_join_and_destroy(priv->read_thrd);
 		priv->read_thrd = NULL;
+	} else if (!priv->thrd_stop) {
+		iiod_responder_reader_worker(priv);
 	}
 }
 

iiod-responder.h

@@ -91,6 +91,9 @@ void iiod_io_set_timeout(struct iiod_io *io, unsigned int timeout_ms);
 /* Read the current value of the micro-second counter */
 uint64_t iiod_responder_read_counter_us(void);
 
+/* Stop the iiod_responder. */
+void iiod_responder_stop(struct iiod_responder *responder);
+
 /* Wait until the iiod_responder stops. */
 void iiod_responder_wait_done(struct iiod_responder *responder);
 

iiod/CMakeLists.txt

@@ -12,7 +12,7 @@ set(CMAKE_REQUIRED_LIBRARIES)
 set(CMAKE_REQUIRED_DEFINITIONS)
 
 add_executable(iiod
-	iiod.c interpreter.c responder.c thread-pool.c
+	iiod.c interpreter.c responder.c rw.c thread-pool.c
 )
 set_target_properties(iiod PROPERTIES
 	C_STANDARD 99