/
4_server_select.c
127 lines (122 loc) · 2.94 KB
/
4_server_select.c
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#include <sys/socket.h>
#include <sys/un.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <unistd.h>
#include <pthread.h>
#include <netdb.h>
#include <arpa/inet.h>
int
interact(int client_sock)
{
int buffer = 0;
ssize_t size = recv(client_sock, &buffer, sizeof(buffer), 0);
if (size <= 0)
return (int) size;
printf("Received %d\n", buffer);
buffer++;
size = send(client_sock, &buffer, sizeof(buffer), 0);
if (size > 0)
printf("Sent %d\n", buffer);
return (int) size;
}
int
fill_fdset(fd_set *set, int *clients, int client_count, int server)
{
int max_fd = server;
FD_ZERO(set);
FD_SET(server, set);
for (int i = 0; i < client_count; ++i) {
FD_SET(clients[i], set);
if (clients[i] > max_fd)
max_fd = clients[i];
}
return max_fd;
}
void
remove_client(int **clients, int *client_count, int i)
{
--*client_count;
int *new_clients = malloc(*client_count * sizeof(int));
memcpy(new_clients, *clients, i * sizeof(int));
memcpy(new_clients + i, *clients + i + 1,
(*client_count - i) * sizeof(int));
free(*clients);
*clients = new_clients;
}
int
main(int argc, const char **argv)
{
int server = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (server == -1) {
printf("error = %s\n", strerror(errno));
return -1;
}
struct sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_port = htons(12345);
inet_aton("127.0.0.1", &addr.sin_addr);
if (bind(server, (struct sockaddr *) &addr, sizeof(addr)) != 0) {
printf("bind error = %s\n", strerror(errno));
return -1;
}
if (listen(server, 128) == -1) {
printf("listen error = %s\n", strerror(errno));
return -1;
}
int *clients = NULL;
int client_count = 0;
fd_set readset;
while(1) {
int max_fd = fill_fdset(&readset, clients, client_count,
server);
struct timeval timeval;
timeval.tv_sec = 2;
timeval.tv_usec = 0;
int nfds = select(max_fd + 1, &readset, NULL, NULL, &timeval);
if (nfds == 0) {
printf("Timeout\n");
continue;
}
if (nfds == -1) {
printf("error = %s\n", strerror(errno));
break;
}
if (FD_ISSET(server, &readset)) {
int client_sock = accept(server, NULL, NULL);
if (client_sock == -1) {
printf("error = %s\n", strerror(errno));
break;
}
printf("New client\n");
client_count++;
clients = realloc(clients, client_count * sizeof(int));
clients[client_count - 1] = client_sock;
nfds--;
}
for (int i = 0; i < client_count && nfds > 0; ++i) {
if (! FD_ISSET(clients[i], &readset))
continue;
nfds--;
printf("Interact with fd %d\n", clients[i]);
int rc = interact(clients[i]);
if (rc == -1) {
printf("error = %s\n", strerror(errno));
if (errno != EWOULDBLOCK && errno != EAGAIN)
break;
} else if (rc == 0) {
printf("Client disconnected\n");
remove_client(&clients, &client_count, i);
}
}
}
close(server);
for (int i = 0; i < client_count; ++i)
close(clients[i]);
free(clients);
return 0;
}