/**************************************************************/ /* This program uses the Select function to control sockets */ /**************************************************************/ #include <stdio.h> #include <stdlib.h> #include <errno.h> #include <string.h> #include <sys/types.h> #include <netinet/in.h> #include <sys/socket.h> #include <sys/wait.h> #define MYPORT 3456 /* the port users will be connecting to */ #define BACKLOG 10 /* how many pending connections queue will hold */ main() { int sockfd, new_fd; /* listen on sock_fd, new connection on new_fd */ struct sockaddr_in my_addr; /* my address information */ struct sockaddr_in their_addr; /* connector's address information */ int sin_size; struct timeval tv; /*The time wait for socket to be changed */ fd_set readfds, writefds, exceptfds; /*File descriptors for read, write and exceptions */ FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds); if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) { perror("socket"); exit(1); } my_addr.sin_family = AF_INET; /* host byte order */ my_addr.sin_port = htons(MYPORT); /* short, network byte order */ my_addr.sin_addr.s_addr = INADDR_ANY; /* auto-fill with my IP */ bzero(&(my_addr.sin_zero), 8); /* zero the rest of the struct */ if (bind(sockfd, (struct sockaddr *)&my_addr, sizeof(struct sockaddr)) \ == -1) { perror("bind"); exit(1); } if (listen(sockfd, BACKLOG) == -1) { perror("listen"); exit(1); } while(1) { /* main accept() loop */ FD_SET(sock_fd, &readfds); /*Add sock_fd to the set of file descriptors to read from */ tv.sec = 30; /*Initiate time to wait for fd to change */ if (select(sock_fd + 1, &readfds, 0, 0, &tv) < 0) { perror("select"); continue; } sin_size = sizeof(struct sockaddr_in); if ((new_fd = accept(sockfd, (struct sockaddr *)&their_addr, \ &sin_size)) == -1) { perror("accept"); continue; } printf("server: got connection from %s\n", \ inet_ntoa(their_addr.sin_addr)); if (send(new_fd, "Hello, world!\n", 14, 0) == -1) perror("send"); close(new_fd); } }