Unix domain sockets example

socket_client.cpp

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/types.h>

static const char* socket_path = "/home/mysocket";
static const unsigned int s_recv_len = 200;
static const unsigned int s_send_len = 100;

int main()
{
	int sock = 0;
	int data_len = 0;
	struct sockaddr_un remote;
	char recv_msg[s_recv_len];
	char send_msg[s_send_len];

	memset(recv_msg, 0, s_recv_len*sizeof(char));
	memset(send_msg, 0, s_send_len*sizeof(char));

	if( (sock = socket(AF_UNIX, SOCK_STREAM, 0)) == -1  )
	{
		printf("Client: Error on socket() call \n");
		return 1;
	}

	remote.sun_family = AF_UNIX;
	strcpy( remote.sun_path, socket_path );
	data_len = strlen(remote.sun_path) + sizeof(remote.sun_family);

	printf("Client: Trying to connect... \n");
	if( connect(sock, (struct sockaddr*)&remote, data_len) == -1 )
	{
		printf("Client: Error on connect call \n");
		return 1;
	}

	printf("Client: Connected \n");

	while( printf(">"), fgets(send_msg, s_send_len, stdin), !feof(stdin))
	{
		if( send(sock, send_msg, strlen(send_msg)*sizeof(char), 0 ) == -1 )
		{
			printf("Client: Error on send() call \n");
		}
		memset(send_msg, 0, s_send_len*sizeof(char));
		memset(recv_msg, 0, s_recv_len*sizeof(char));

		if( (data_len = recv(sock, recv_msg, s_recv_len, 0)) > 0 )
		{
			printf("Client: Data received: %s \n", recv_msg);
		}
		else
		{
			if(data_len < 0)
			{
				printf("Client: Error on recv() call \n");
			}
			else
			{
				printf("Client: Server socket closed \n");
				close(sock);
				break;
			}

		}
	}

	printf("Client: bye! \n");

	return 0;
}

socket_server.cpp

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/types.h>

static const char* socket_path = "/home/mysocket";
static const unsigned int nIncomingConnections = 5;

int main()
{
	//create server side
	int s = 0;
	int s2 = 0;
	struct sockaddr_un local, remote;
	int len = 0;

	s = socket(AF_UNIX, SOCK_STREAM, 0);
	if( -1 == s )
	{
		printf("Error on socket() call \n");
		return 1;
	}

	local.sun_family = AF_UNIX;
	strcpy( local.sun_path, socket_path );
	unlink(local.sun_path);
	len = strlen(local.sun_path) + sizeof(local.sun_family);
	if( bind(s, (struct sockaddr*)&local, len) != 0)
	{
		printf("Error on binding socket \n");
		return 1;
	}

	if( listen(s, nIncomingConnections) != 0 )
	{
		printf("Error on listen call \n");
	}

	bool bWaiting = true;
	while (bWaiting)
	{
		unsigned int sock_len = 0;
		printf("Waiting for connection.... \n");
		if( (s2 = accept(s, (struct sockaddr*)&remote, &sock_len)) == -1 )
		{
			printf("Error on accept() call \n");
			return 1;
		}

		printf("Server connected \n");

		int data_recv = 0;
		char recv_buf[100];
		char send_buf[200];
		do{
			memset(recv_buf, 0, 100*sizeof(char));
			memset(send_buf, 0, 200*sizeof(char));
			data_recv = recv(s2, recv_buf, 100, 0);
			if(data_recv > 0)
			{
				printf("Data received: %d : %s \n", data_recv, recv_buf);
				strcpy(send_buf, "Got message: ");
				strcat(send_buf, recv_buf);

				if(strstr(recv_buf, "quit")!=0)
				{
					printf("Exit command received -> quitting \n");
					bWaiting = false;
					break;
				}

				if( send(s2, send_buf, strlen(send_buf)*sizeof(char), 0) == -1 )
				{
					printf("Error on send() call \n");
				}
			}
			else
			{
				printf("Error on recv() call \n");
			}
		}while(data_recv > 0);

		close(s2);
	}


	return 0;
}