books/tcpv1/day-time/daytimetcpsrv.c

   1 #include <stdio.h>
   2 #include <time.h>
   3 #include <unistd.h>
   4 #include <stdlib.h>
   5 #include <string.h>
   6 #include <sys/types.h>
   7 #include <sys/socket.h>
   8 #include <arpa/inet.h>
   9
  10 #define MAXLINE 4096
  11
  12 int main(int argc, char *argv[])
  13 {
  14         ssize_t ret;
  15         time_t ticks;
  16         char buf[MAXLINE];
  17         int err, len, listenfd, connfd;
  18         struct sockaddr_in servaddr, cliaddr;
  19
  20         listenfd = socket(AF_INET, SOCK_STREAM, 0);
  21         if (listenfd < 0) {
  22                 perror("socket()");
  23                 exit(1);
  24         }
  25
  26         memset(&servaddr, 0, sizeof(servaddr));
  27         servaddr.sin_family = AF_INET;
  28         servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
  29         servaddr.sin_port = htons(13);
  30
  31         err = bind(listenfd, (struct sockaddr *) &servaddr, sizeof(servaddr));
  32         if (err < 0) {
  33                 perror("bind()");
  34                 exit(1);
  35         }
  36
  37         err = listen(listenfd, 3);
  38         if (err < 0) {
  39                 perror("listen()");
  40                 exit(1);
  41         }
  42
  43         for (;;) {
  44                 len = sizeof(cliaddr);
  45                 connfd = accept(listenfd, (struct sockaddr *) &cliaddr, &len);
  46                 if (connfd < 0) {
  47                         perror("accept()");
  48                         exit(1);
  49                 }
  50                 printf("connection from %s, port %d\n",
  51                        inet_ntop(AF_INET, &cliaddr.sin_addr, buf, sizeof(buf)),
  52                        ntohs(cliaddr.sin_port));
  53
  54                 ticks = time(NULL);
  55                 memset(buf, '\0', sizeof(buf));
  56                 snprintf(buf, sizeof(buf), "%.24s", ctime(&ticks));
  57                 printf("%s: Handling a connection\n", buf);
  58
  59                 memset(buf, '\0', sizeof(buf));
  60                 snprintf(buf, sizeof(buf), "%.24s\r\n", ctime(&ticks));
  61                 ret = write(connfd, buf, strlen(buf));
  62                 if (ret != strlen(buf)) {
  63                         perror("write()");
  64                         exit(1);
  65                 }
  66
  67                 err = close(connfd);
  68                 if (err < 0) {
  69                         perror("close()");
  70                         exit(1);
  71                 }
  72         }
  73
  74         exit(0);
  75 }