initial

NumberServer/Makefile

@@ -0,0 +1,14 @@
+CC=gcc
+CFLAGS=-std=gnu99
+LDFLAGS=-lpthread
+
+lfs:	lfs.o
+	$(CC) -o $@ $(LDFLAGS) $^
+
+.c.o:
+	$(CC) $(CFLAGS) -c $<
+
+.PHONY: clean
+clean:
+	-rm -f *.o lfs
+

NumberServer/lfs.c

@@ -0,0 +1,123 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <unistd.h>
+#include <pthread.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <string.h>
+#include <errno.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+
+
+pthread_mutex_t lock;
+volatile uint64_t value;
+
+static void *linearFeedbackShiftRegisterHandler(void *v) {
+	static uint64_t reg = 0x1;
+
+	while(1) {
+		pthread_mutex_lock(&lock);
+		value = reg;
+		pthread_mutex_unlock(&lock);
+		
+		uint8_t z = ((reg >> 64-1) & 1) ^ ((reg >> 63-1) & 1) ^
+			    ((reg >> 61-1) & 1) ^ ((reg >> 60-1) & 1);
+		reg <<= 1;
+		reg |= z;
+
+		sleep(1);
+	}
+}
+
+static void *readerHandler(void *v) {
+	while(1) {
+		uint64_t reg;
+
+		pthread_mutex_lock(&lock);
+		reg = value;
+		pthread_mutex_unlock(&lock);
+
+		printf("%" PRIx64 "\n", reg);
+
+		sleep(5);
+	}
+}
+
+static void *listenerHandler(void *v) {
+	int serverSocket = socket(AF_INET, SOCK_STREAM, 0);
+	if (serverSocket == -1) {
+		printf("Unable to create socket: %d\n", errno);
+		exit(3);
+	}
+	
+	struct sockaddr_in serverAddress;
+	serverAddress.sin_family = AF_INET;
+	serverAddress.sin_addr.s_addr = INADDR_ANY;
+	serverAddress.sin_port = htons(15000);
+	if (-1 == bind(serverSocket, 
+                       (struct sockaddr*) &serverAddress,
+		       sizeof(serverAddress))) {
+		printf("Unable to bind: %d\n", errno);
+	}
+	if (-1 == listen(serverSocket, 5)) {
+		printf("Unable to listen: %d\n", errno);
+		exit(4);
+	}
+
+	while (1) {
+		struct sockaddr_in *clientAddr;
+		socklen_t clientAddrLen;
+		int clientSocket = accept(serverSocket, 
+					  (struct sockaddr *) clientAddr, 
+					  &clientAddrLen);
+		if (clientSocket == -1) {
+			printf("Failure when accepting: %d\n", errno);
+		} else {
+			uint64_t reg;
+			pthread_mutex_lock(&lock);
+			reg = value;
+			pthread_mutex_unlock(&lock);
+			char buf[128];
+			sprintf(buf, "%" PRIx64 "\n", reg);
+			write(clientSocket, buf, strlen(buf)+1);	
+		}
+		close(clientSocket);
+	}
+}
+
+
+int main(void) {
+	pthread_mutex_init(&lock, NULL);
+
+	pthread_t linearFeedbackShiftRegister;
+	int rc = pthread_create(&linearFeedbackShiftRegister, NULL, 
+				&linearFeedbackShiftRegisterHandler, NULL);
+	if (rc != 0) {
+		printf("Unable to start shifter thread\n");
+		exit(1);
+	}
+
+	pthread_t reader;
+	rc = pthread_create(&reader, NULL, 
+				&readerHandler, NULL);
+	if (rc != 0) {
+		printf("Unable to start reader thread\n");
+		exit(2);
+	}
+
+	pthread_t listener;
+	rc = pthread_create(&listener, NULL, 
+				&listenerHandler, NULL);
+	if (rc != 0) {
+		printf("Unable to start listener thread\n");
+		exit(6);
+	}
+
+	pthread_join(linearFeedbackShiftRegister, NULL);
+	pthread_join(reader, NULL);
+	pthread_join(listener, NULL);
+}
+