C select() issue in client server application - c

Question

I am working on a client/server c project in which I have a server and multiple clients sending requests to it. The application uses sockets for communication (AF_UNIX) and the whole connection part is fine (to say, using other methods rather than the select() one makes everything work just fine).
However, I am willing to use select() in order to notify the server of new events on the file descriptors in the set, which are the server socket fd and the single clients ones.
I have cleared the code from the parts which are not relevant to the issue I'm facing and now I only have the following:
The server, that initializes the socket communication and created a thread which has to perform the select() and accept() functions:
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include <pthread.h>
#include <sys/types.h>
#include <errno.h>
#include <sys/un.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <string.h>
#include <utility.h>
void* handConn(void* address){
int fd_cli;
while(1){
printf("HANDLER: in handler\n");
if (select(max_fd+1, &rdset,NULL, NULL,NULL) == -1) {
perror("select");
exit(EXIT_FAILURE);
}
for(int i=0; i<=max_fd; i++){
if(FD_ISSET(i,&rdset) && i==sfd){
printf("new incoming connection to accept\n");
fd_cli=accept(sfd,NULL,NULL);
FD_SET(fd_cli,&rdset);
if(fd_cli>max_fd) max_fd=fd_cli;
}
else if(FD_ISSET(i,&rdset) && i!=sfd){
printf("event on old connection\n");
}
}
FD_ZERO(&rdset);
}
return (void*) NULL;
}
int main(void){
int i, fd_cli, tid;
max_fd=0;
struct sockaddr_un sa;
sa.sun_family=AF_UNIX;
strncpy(sa.sun_path,"tmp/sock", sizeof(sa.sun_path));
if((sfd=socket(AF_UNIX,SOCK_STREAM,0))<0){
perror("Server socket");
exit(EXIT_FAILURE);
}
if ( bind(sfd,(struct sockaddr *)&sa, sizeof(sa))<0){
perror("bind");
exit(EXIT_FAILURE);
}
listen(sfd,10); //10 is just for example purpose only
/* Init fd_set */
FD_ZERO(&rdset);
FD_SET(sfd, &rdset);
max_fd=sfd;
/*Handler thread creation */
if( pthread_create(&tid, NULL, handConn, (void*) &sa)<0){
perror("Handler thread creation");
exit(EXIT_FAILURE);
}
pthread_join(tid, NULL);
return 0;
}
The client, which performs the following (I removed the wrote-bytes control from the code because it is not relevant in this case):
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <errno.h>
#include <utility.h>
int main(){
int fd_cli;
struct sockaddr_un sa;
sa.sun_family=AF_UNIX;
strncpy(sa.sun_path,"tmp/sock", sizeof(sa.sun_path));
if( (fd_cli = socket(AF_UNIX, SOCK_STREAM, 0))==-1){
perror("Client socket connection");
return -1;
}
while( (connect(fd_cli,(struct sockaddr*)&sa, sizeof(struct sockaddr_un))) == -1 ) {
if ( errno == ENOENT ) { sleep(1); }
else{
perror("Connect");
exit(EXIT_FAILURE);
}
}
printf("connected to server\n");
/*write something to server*/
int retvalue = write(sfd, writePointer, bytesLeft);
if(retvalue=0) /*handle...*/
if(retvalue==-1){
perror("writing");
return -1;
}
close(fd_cli);
return 0;
}
Last, the library in which are defined the variables used in the codes above:
#ifndef utility_h
#define utility_h
#include <stdio.h>
#include <stdlib.h>
#include <sys/select.h>
fd_set reset;
int sfd; //server fd
int max_fd;
The issue I am facing is that by executing even just one client, the select does not see the incoming connection.
What I would expect is the handler to print the following:
new incoming connection to accept
event on old connection
the first before doing the accept and the second when it intercepts the write.
The program, as it is don't print neither of those, so the handler can't even intercept a new incoming connection.
It just does nothing but getting stuck on select().
What might the issue be?