generic command and Makefile

Makefile

@@ -0,0 +1,13 @@
+BIN=bin
+
+all: dirs command
+
+command: command.c
+	gcc -o ${BIN}/command command.c
+
+.PHONY: clean dirs
+clean:
+	rm -rf ${BIN}
+
+dirs:
+	mkdir -p ${BIN}

command.c

@@ -0,0 +1,83 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <sys/socket.h>
+#include <sys/types.h> // BSD compatible
+#include <arpa/inet.h>
+#include <unistd.h>
+
+#include <errno.h>
+#include <netdb.h>
+
+#define SERVER "::1"
+#define PORT 49000
+
+#define COMMAND_BUFFER 256
+
+char* printable(char *str) {
+	char *ret = strdup(str);
+
+	for (int i = strlen(ret); i >= 0; i--) {
+		if (ret[i] == '\r' || ret[i] == '\n') {
+			ret[i] = '\0';
+		}
+	}
+
+	return ret;
+}
+
+void sendCommand(int sock, char *cmd) {
+	char bytesToSend[COMMAND_BUFFER];
+	memset(bytesToSend, 0, COMMAND_BUFFER);
+
+	strcpy(&bytesToSend[0], "CMND");
+	strcpy(&bytesToSend[5], cmd);
+
+	int numBytesSend = send(sock, bytesToSend, 5 + strlen(cmd), 0);
+	if (numBytesSend >= 0) {
+		//printf("Send %d bytes to %s:%d: %s\n", numBytesSend, SERVER, PORT, printable(bytesToSend));
+	} else {
+		fprintf(stderr, "Failed to send message to %s:%d (%d): %s", SERVER, PORT, errno, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+}
+
+int main(int argc, char *argv[]) {
+	int xplaneSocket;
+	struct sockaddr_in6 xplaneAddress;
+
+	int err;
+
+	// check argument
+	if (argc != 2) {
+		fprintf(stderr, "Usage: %s <command>\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	// create socket
+	xplaneSocket = socket(AF_INET6, SOCK_DGRAM, 0);
+	if (xplaneSocket == -1) {
+		fprintf(stderr, "Error creating socket (%d): %s\n", errno, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	// prepare address struct
+	xplaneAddress.sin6_family = AF_INET6;
+	xplaneAddress.sin6_port = htons(PORT);
+	inet_pton(AF_INET6, SERVER, &xplaneAddress.sin6_addr.s6_addr);
+
+	// connect to xplane
+	err = connect(xplaneSocket, (struct sockaddr *)&xplaneAddress, sizeof(xplaneAddress));
+	if (err) {
+		fprintf(stderr, "Error connecting %s:%d (%d): %s\n", SERVER, PORT, err, gai_strerror(err));
+		exit(EXIT_FAILURE);
+	}
+
+	// send payload
+	sendCommand(xplaneSocket, argv[1]);
+
+	// bye bye (and no, I don't care about error anymore; I'll exit anyway?!)
+	close(xplaneSocket);
+	exit(EXIT_SUCCESS);
+}