Inter-Process-Communication-IPC-/AF_UNIX/client.c

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

#define SOCKET_NAME "/tmp/DemoSocket"
#define BUFFER_SIZE 128

int
main(int argc, char* argv[]) {

	struct sockaddr_un addr;
	int i;
	int ret;
	int data_socket;
	char buffer[BUFFER_SIZE];

	/* Create data socket */
	/* Client side don't have any concept of Master socket.
	   It directly use data socket to communicate with server. */

	data_socket = socket(AF_UNIX, SOCK_STREAM, 0);

	if (data_socket == -1) {
		perror("socket");
		exit(EXIT_FAILURE);
	}

	/* 
		For portability clear the whole structure, since some implementation
		have additional (nonstandard) fields in the structure.
	*/

	memset(&addr, 0, sizeof(struct sockaddr_un));

	/* Connect socket to socket address. */

	addr.sun_family = AF_UNIX;
	strncpy(addr.sun_path, SOCKET_NAME, sizeof(addr.sun_path) - 1);

	ret = connect(data_socket, (const struct sockaddr*)&addr,
		sizeof(struct sockaddr_un));

	if (ret == -1) {
		fprintf(stderr, "The server is down.\n");
		exit(EXIT_FAILURE);
	}

	/* Send arguments */
	do {

		printf("Enter number to send to server :\n");
		scanf("%d", &i);
		ret = write(data_socket, &i, sizeof(int));
		if (ret == -1) {
			perror("write");
			exit(EXIT_FAILURE);
		}

		printf("No of bytes sent = %d, data sent = %d\n", ret, i);
	} while (i);

	/* Request result */

	memset(buffer, 0, BUFFER_SIZE);
	strncpy(buffer, "RES", strlen("RES"));
	buffer[strlen(buffer)] = '\0';

	ret = read(data_socket, buffer, BUFFER_SIZE);
	if (ret == -1) {
		perror("read");
		exit(EXIT_FAILURE);
	}

	/* Ensure buffer is 0 - terminated */

	buffer[BUFFER_SIZE - 1] = 0;
	printf("%s\n", buffer);

	/* Close socket */

	close(data_socket);
	exit(EXIT_SUCCESS);
	return 0;
}