C - Sockets. client: connect: No such file or directory - c

Question

I'm trying to set up a socket connection between a client and server where server creates socket and reads from it and client writes data to a server. Here is my code:
//server.c
/* a server in the unix domain.*/
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/un.h>
#include <stdio.h>
#define SOCKETNAME "mynewsocket"
int main(void){
char buffer[1024];
int n, sock , nsock;
socklen_t len;
struct sockaddr_un name;
if((sock = socket(AF_UNIX, SOCK_STREAM, 0))<0){
perror("server: socket");
exit(1);
}
memset(&name, 0, sizeof(struct sockaddr_un));
name.sun_family = AF_UNIX;
strcpy(name.sun_path, SOCKETNAME);
len = sizeof(name.sun_family) + strlen(name.sun_path);
unlink ( name.sun_path ) ;
if (bind(sock, (struct sockaddr *) &name, SUN_LEN(&name)) < 0) {
perror("server: bind");
exit(1);
}
if (listen(sock, 5) < 0) {
perror("server: listen");
exit(1);
}
if ((nsock = accept(sock, (struct sockaddr *) &name, &len)) < 0) {
perror("server: accept");
exit(1);
}
n=read(nsock,buffer,80);
printf("A connection has been established\n");
write(1,buffer,n);
write(nsock,"I got your message\n",19);
close(nsock);
close(sock);
exit(0);
}
and client...
//client.c
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/un.h>
#include <stdio.h>
#define SOCKETNAME "mynewsocket"
int main(void){
char buffer [1024];
int n, sock, len;
struct sockaddr_un name;
if((sock = socket(AF_UNIX, SOCK_STREAM, 0))<0){
perror("client: socket");
exit(1);
}
memset(&name, 0, sizeof(struct sockaddr_un));
name. sun_family = AF_UNIX;
strcpy(name.sun_path, SOCKETNAME);
len = sizeof(name.sun_family) + strlen(name.sun_path);
unlink ( name.sun_path ) ;
if (connect(sock, (struct sockaddr *) &name, SUN_LEN(&name)) < 0) {
perror("client: connect");
exit(1);
}
printf("Please enter your message: ");
bzero(buffer,82);
fgets(buffer,80,stdin);
write(sock,buffer,strlen(buffer));
n=read(sock,buffer,80);
printf("The return message was\n");
write(1,buffer,n);
close(sock);
exit(0);
}
To run the two programs, compile first and run it like this:
./server &
./client
When I run the two programs, the server executes fine but the client executes with an error saying No such file or directory
Why is that? What is wrong with my code?

Answer 1

unlink ( name.sun_path ) ;
Why do you unlink? This is the rendez-vous point for client&server! The server could create this file on the file system once it starts running , and unlink it when it exits. (but that is not needed)
The client uses the file to find the server. (te "secret" they share is the location and name of the socket-file.
AF_UNIX uses the file system as a namespace(filenames instead of ip-addresses+portnumbers) Internally, (most probably) the {dev_id,inodenumber} are used as "key" to identify the socket/file-descriptor