C Socket: read finish on close in server - c

Question

I have a simply program with server and client that comunicate with AF_STREAM socket.
Client will can send multiple request to server, and the server response with a string but I don't know the lenght. The client stops in reading when read return 0 and restarts after the server stops the comunication. I don't understand why.
//SEVER
int main(void){
int idSockServer, idSockClient, clientLen;
struct sockaddr_in indirizzoClient, indirizzoServer;
unsigned short richiesta = 0;
char nomeFile[L_STRING], buffer[L_BUFFER];
printf("Inizializzaione del server\n");
idSockServer = socket(AF_INET, SOCK_STREAM, 0);
if(idSockServer == -1){
fprintf(stderr, "Errore socket\n");
exit(EXIT_FAILURE);
}
indirizzoServer.sin_addr.s_addr = htonl(INADDR_ANY);
indirizzoServer.sin_port = htons(5566);
indirizzoServer.sin_family = AF_INET;
if(bind(idSockServer, (struct sockaddr *) &indirizzoServer, sizeof(indirizzoServer))){
fprintf(stderr, "Errore bind\n");
exit(EXIT_FAILURE);
}
if(listen(idSockServer, 5) == -1){
fprintf(stderr, "Errore listen\n");
exit(EXIT_FAILURE);
}
while(1){
printf("[SERVER] Pronto!\n");
clientLen = sizeof(indirizzoClient);
idSockClient = accept(idSockServer, (struct sockaddr *) &indirizzoClient, &clientLen);
if(idSockClient == -1){
printf("[SERVER] Errore alla connessione\n");
continue;
}
read(idSockClient, &richiesta, L_BUFFER);
switch(richiesta){
case 1:
printf("[SERVER] Richiesta 1 accetata, invio risposta\n");
//this simulates the variable lenght string
strcpy(buffer, "un file\n");
write(idSockClient, buffer, L_BUFFER);
break;
}
sleep(6);
close(idSockClient);
}
}
Here the client
//CLIENT
int main(void) {
int sockIdClient, clientLen, file, len;
char buffer[L_BUFFER], nomeFile[L_STRING];
struct sockaddr_in indirizzoClient;
unsigned short scelta, risposta = 0;
sockIdClient = socket(AF_INET, SOCK_STREAM, 0);
if (sockIdClient == -1) {
perror("Errore creazione socket");
exit(EXIT_FAILURE);
}//fine if creazione socket
indirizzoClient.sin_addr.s_addr = htonl(INADDR_ANY);
indirizzoClient.sin_family = AF_INET;
indirizzoClient.sin_port = htons(5566);
if (connect(sockIdClient, (struct sockaddr *) &indirizzoClient, sizeof (indirizzoClient)) == -1) {
perror("Errore connessione al server");
exit(EXIT_FAILURE);
}//fine connect
do {
printf("1) File disponibili\n");
printf("2) Scarica file\n");
printf("0) Esci\n");
printf("Scelta --> ");
scanf("%hu", &scelta);
switch (scelta) {
case 1:
write(sockIdClient, &scelta, sizeof (unsigned short));
len = read(sockIdClient, buffer, L_BUFFER);
while (len > 0) {
printf("%s", buffer);
printf("%d\n", len);
len = read(sockIdClient, buffer, len);
}
break;
case 2:
//This part of code is not managed by Server yet
write(sockIdClient, &scelta, sizeof (unsigned short));
read(sockIdClient, &risposta, sizeof (int));
if (risposta) {
printf("Nome file: ");
leggiStringa(nomeFile, L_STRING);
write(file = sockIdClient, nomeFile, L_STRING);
if (open(nomeFile, O_WRONLY | O_CREAT, "0666") == -1) {
perror("Errore apertura del file");
close(sockIdClient);
exit(EXIT_FAILURE);
}//fine open
len = read(sockIdClient, buffer, L_BUFFER);
while (len > 0) {
write(file, buffer, L_BUFFER);
printf("leggo..\n");
len = read(sockIdClient, buffer, len);
}
close(file);
} else printf("Il server non ha accetato la richiesta\n");
break;
default:
printf("Scelta non valida");
}
} while (scelta != 0);
close(sockIdClient);
}