3_server.c

#include <sys/socket.h>
#include <sys/un.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <unistd.h>
#include <pthread.h>
#include <netdb.h>
#include <arpa/inet.h>

void *
worker_f(void *arg)
{
	printf("New client created\n");
	int client_sock = (int)(uintptr_t)arg;
	while(1) {
		int buffer = 0;
		ssize_t size = recv(client_sock, &buffer, sizeof(buffer), 0);
		if (size == -1) {
			printf("error = %s\n", strerror(errno));
			continue;
		}
		if (size == 0) {
			printf("Closed connection\n");
			break;
		}
		printf("Received %d\n", buffer);
		buffer++;
		if (send(client_sock, &buffer, sizeof(buffer), 0) == -1)
			printf("error = %s\n", strerror(errno));
		else
			printf("Sent %d\n", buffer);
	}
	close(client_sock);
	return NULL;
}

int
main(int argc, const char **argv)
{
	int sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if (sock == -1) {
		printf("error = %s\n", strerror(errno));
		return -1;
	}
	struct sockaddr_in addr;
	addr.sin_family = AF_INET;
	addr.sin_port = htons(12345);
	inet_aton("127.0.0.1", &addr.sin_addr);

	if (bind(sock, (struct sockaddr *) &addr, sizeof(addr)) != 0) {
		printf("bind error = %s\n", strerror(errno));
		return -1;
	}
	if (listen(sock, 128) == -1) {
		printf("listen error = %s\n", strerror(errno));
		return -1;
	}
	pthread_attr_t attr;
	pthread_attr_init(&attr);
	pthread_attr_setdetachstate(&attr, 1);
	while(1) {
		pthread_t worker_thread;
		int client_sock = accept(sock, NULL, NULL);
		if (client_sock == -1) {
			printf("error = %s\n", strerror(errno));
			continue;
		}
		int rc = pthread_create(&worker_thread, &attr, worker_f,
					(void *)(uintptr_t)client_sock);
		if (rc != 0) {
			printf("error = %s\n", strerror(rc));
			close(client_sock);
		}
	}
	pthread_attr_destroy(&attr);
	close(sock);
	return 0;
}