xvc_server: don't stop when connection close, rework read to return code for error and for disconnect

src/xvc_server.cpp

@@ -6,6 +6,7 @@
 #include "xvc_server.hpp"
 
 #include <arpa/inet.h>
+#include <errno.h>
 #include <netinet/tcp.h>
 #include <unistd.h>
 
@@ -185,12 +186,14 @@ void XVC_server::thread_listen()
 					}
 				} else {
 					int ret = handle_data(fd);
+					if (ret != 0) {
 						printInfo("connection closed - fd " + std::to_string(fd));
 						close(fd);
 						FD_CLR(fd, &conn);
-					if (ret == 1)
+						if (ret == 3)
 							throw std::runtime_error("communication failure");
 					}
+				}
 			} else if (FD_ISSET(fd, &except)) {
 				printWarn("connection aborted - fd " + std::to_string(fd));
 				close(fd);
@@ -223,30 +226,39 @@ int XVC_server::sread(int fd, void *target, int len)
 	unsigned char *t = (unsigned char *)target;
 	while (len) {
 		int r = read(fd, t, len);
-        if (r <= 0)
+		if (r == 0) // connection closed
-            return r;
+			return 2;
+		else if (r < 0) {
+			char err[256];
+			snprintf(err, 256, "Read error (%d) %d %s\n", r,
+				errno, strerror(errno));
+			printError(err);
+			return 3;
+		}
+
 		t += r;
 		len -= r;
 	}
 	return 1;
 }
 
-
 int XVC_server::handle_data(int fd)
 {
 	char xvcInfo[32];
+	int ret;
 
 	do {
 		char cmd[16];
 		memset(cmd, 0, 16);
 
-		if (sread(fd, cmd, 2) != 1)
+		if ((ret = sread(fd, cmd, 2)) != 1) {
-			return 1;
+			return ret;
+		}
 
 		/* getinfo */
 		if (memcmp(cmd, "ge", 2) == 0) {
-			if (sread(fd, cmd, 6) != 1)
+			if ((ret = sread(fd, cmd, 6)) != 1)
-				return 1;
+				return ret;
 			snprintf(xvcInfo, sizeof(xvcInfo),
 				"xvcServer_v1.0:%u\n", _buffer_size);
 			if (send(fd, xvcInfo, strlen(xvcInfo), 0) !=
@@ -262,8 +274,8 @@ int XVC_server::handle_data(int fd)
 			break;
 		/* settck */
 		} else if (memcmp(cmd, "se", 2) == 0) {
-			if (sread(fd, cmd, 9) != 1)
+			if ((ret = sread(fd, cmd, 9)) != 1)
-				return 1;
+				return ret;
 			memcpy(_result, cmd + 5, 4);
 			if (write(fd, _result, 4) != 4) {
 				printError("write");
@@ -285,20 +297,20 @@ int XVC_server::handle_data(int fd)
 			}
 			break;
 		} else if (memcmp(cmd, "de", 2) == 0) {	 // DEBUG CODE
-			if (sread(fd, cmd, 3) != 1)
+			if ((ret = sread(fd, cmd, 3)) != 1)
-				return 1;
+				return ret;
 			printf("%u : Received command: 'debug'\n",
 				   (int)time(NULL));
 			break;
 		} else if (memcmp(cmd, "of", 2) == 0) {	 // DEBUG CODE
-			if (sread(fd, cmd, 1) != 1)
+			if ((ret = sread(fd, cmd, 1)) != 1)
-				return 1;
+				return ret;
 			printf("%u : Received command: 'off'\n",
 				   (int)time(NULL));
 			break;
 		} else if (memcmp(cmd, "sh", 2) == 0) {
-			if (sread(fd, cmd, 4) != 1)
+			if ((ret = sread(fd, cmd, 4)) != 1)
-				return 1;
+				return ret;
 			if (_verbose) {
 				printInfo(std::to_string((int)time(NULL)) +
 						" : Received command: 'shift'");
@@ -311,9 +323,9 @@ int XVC_server::handle_data(int fd)
 		/* Handling for -> "shift:<num bits><tms vector><tdi vector>" */
 		uint32_t len, nr_bytes;
 		/* 1. len */
-		if (sread(fd, &len, 4) != 1) {
+		if ((ret = sread(fd, &len, 4)) != 1) {
 			printError("reading length failed");
-			return 1;
+			return ret;
 		}
 
 		/* 2. convert len (in bits) to nr_bytes (in bytes) */
@@ -326,9 +338,9 @@ int XVC_server::handle_data(int fd)
 
 		/* 3. receive 2 x nr_bytes (TMS + TDI) */
 		memset(_tmstdi, 0, _buffer_size);
-		if (sread(fd, _tmstdi, nr_bytes * 2) != 1) {
+		if ((ret = sread(fd, _tmstdi, nr_bytes * 2)) != 1) {
 			printError("reading data failed");
-			return 1;
+			return ret;
 		}
 		memset(_result, 0, _buffer_size/2);
 

src/xvc_server.hpp

@@ -50,7 +50,8 @@ class XVC_server {
 		void thread_listen();
 		/*!
 		 * \brief parser and dispatcher for XVC transactions
-		 * \return 1 when transactions fails, 0 otherwise
+		 * \return 2 when connection is closed, 1 when transactions fails,
+		 *         0 otherwise
 		 */
 		int handle_data(int fd);
 		/*!
@@ -58,7 +59,7 @@ class XVC_server {
 		 * \param fd: socket descriptor
 		 * \param target: buffer
 		 * \param len: number of bytes to read
-		 * \return <= 0 when failure, 1 otherwise
+		 * \return 3 when failure, 2 when connection closed, 1 otherwise
 		 */
 		int sread(int fd, void *target, int len);
 	    int _verbose;          /*!< verbose level */