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[onus]

Hi,
I am reading and understanding code from a book.
I am copy pasting the exact code which I have.
Following program is for client.c

#include<sys/types.h>

#include<sys/socket.h>

#include <stdio.h>

#include <sys/un.h>

#include <unistd.h>

#include <stdlib.h>

int main() {

int sockfd;

int len;

struct sockaddr_un address;

int result;

char ch = 'A';

        sockfd = socket(AF_UNIX, SOCK_STREAM, 0);

        address.sun_family = AF_UNIX;

        strcpy(address.sun_path, "server_socket");

I was not able to understand the use of server_socket in above strcpy function.
Where does this come to picture

        len = sizeof(address);

        result = connect(sockfd, (struct sockaddr *)&address, len);

        if(result == -1) {

        perror("oops: client1");

        exit(1);

        }


write(sockfd, &ch, 1);

read(sockfd, &ch, 1);

printf("char from server = %c\n", ch);

close(sockfd);

exit(0);

}

When I run the code as

gcc client.c -o client.o

then on terminal I see each time letter B why is that happening.


and following program is for server.c

#include<sys/types.h>

#include<sys/socket.h>

#include<stdio.h>

#include <sys/un.h>

#include <unistd.h>

#include<stdlib.h>

int main()

{

        int server_sockfd, client_sockfd;

        int server_len, client_len;

        struct sockaddr_un server_address;

        struct sockaddr_un client_address;

        unlink("server_socket");

        server_sockfd = socket(AF_UNIX, SOCK_STREAM, 0);

        server_address.sun_family = AF_UNIX;

        strcpy(server_address.sun_path, "server_socket");

I am not clear with use of server_address.sun_path
I understand that server_address is a struct of type sockaddr_un
but what is sun_path I had seen the file linux/un.h
but could not understand.

        server_len = sizeof(server_address);

        bind(server_sockfd, (struct sockaddr *)&server_address, server_len);

        listen(server_sockfd, 5);

        while (1) {

                char ch;

                printf("server waiting\n");

                client_len = sizeof(client_address);

                client_sockfd = accept(server_sockfd,

                                       (struct sockaddr *)&client_address,

                                       &client_len);

                read(client_sockfd, &ch, 1);

                ch++;

                write(client_sockfd, &ch, 1);

                close(client_sockfd);

        }

}