commands/rdate/rdate.c

   1 /*      rdate 1.0 - Set time&date from remote host      Author: Kees J. Bot
   2  *                                                              12 Oct 1995
   3  */
   4 #define nil 0
   5 #include <sys/types.h>
   6 #include <stdio.h>
   7 #include <time.h>
   8 #include <string.h>
   9 #include <fcntl.h>
  10 #include <errno.h>
  11 #include <stdlib.h>
  12 #include <unistd.h>
  13 #include <sys/ioctl.h>
  14 #include <net/hton.h>
  15 #include <net/netlib.h>
  16 #include <net/gen/in.h>
  17 #include <net/gen/netdb.h>
  18 #include <net/gen/tcp.h>
  19 #include <net/gen/tcp_io.h>
  20
  21 void report(const char *label)
  22 {
  23         fprintf(stderr, "rdate: %s: %s\n", label, strerror(errno));
  24 }
  25
  26 void fatal(const char *label)
  27 {
  28         report(label);
  29         exit(1);
  30 }
  31
  32 int main(int argc, char **argv)
  33 {
  34         char *tcp_device;
  35         int fd;
  36         int i;
  37         struct servent *servent;
  38         struct hostent *hostent;
  39         u16_t time_port;
  40         nwio_tcpconf_t tcpconf;
  41         nwio_tcpcl_t tcpcl;
  42         u32_t net_time;
  43         time_t unix_time;
  44
  45         if (argc <= 1) {
  46                 fprintf(stderr, "Usage: rdate host ...\n");
  47                 exit(1);
  48         }
  49
  50         /* Look up the port number of the TCP service "time". */
  51         if ((servent= getservbyname("time", "tcp")) == nil) {
  52                 fprintf(stderr, "rdate: \"time\": unknown service\n");
  53                 exit(1);
  54         }
  55         time_port= servent->s_port;
  56
  57         if ((tcp_device= getenv("TCP_DEVICE")) == nil) tcp_device= TCP_DEVICE;
  58
  59         if ((fd= open(tcp_device, O_RDWR)) < 0) fatal(tcp_device);
  60
  61         /* Try each host on the command line. */
  62         for (i= 1; i < argc; i++) {
  63                 if ((hostent= gethostbyname(argv[i])) == nil) {
  64                         fprintf(stderr, "rdate: %s: unknown host\n", argv[i]);
  65                         continue;
  66                 }
  67
  68                 /* Configure a TCP channel and connect to the remote host. */
  69
  70                 tcpconf.nwtc_flags= NWTC_LP_SEL | NWTC_SET_RA | NWTC_SET_RP;
  71                 memcpy(&tcpconf.nwtc_remaddr, hostent->h_addr, 4);
  72                 tcpconf.nwtc_remport= time_port;
  73                 if (ioctl(fd, NWIOSTCPCONF, &tcpconf) == -1) fatal(tcp_device);
  74
  75                 tcpcl.nwtcl_flags= 0;
  76                 if (ioctl(fd, NWIOTCPCONN, &tcpcl) < 0) {
  77                         report(argv[i]);
  78                         continue;
  79                 }
  80
  81                 /* Read four bytes to obtain the time. */
  82                 switch (read(fd, &net_time, sizeof(net_time))) {
  83                 case -1:
  84                         report(argv[i]);
  85                         continue;
  86                 default:
  87                         fprintf(stderr, "rdate: %s: short read\n", argv[i]);
  88                         continue;
  89                 case sizeof(net_time):
  90                         break;
  91                 }
  92                 break;
  93         }
  94         if (i == argc) exit(1);
  95
  96         /* Internet time is in seconds since 1900, UNIX time is in seconds
  97          * since 1970.
  98          */
  99         unix_time= ntohl(net_time) - 2208988800;
 100
 101         /* Try to set the time and tell us about it. */
 102         if (stime(&unix_time) < 0) {
 103                 printf("time on ");
 104         } else {
 105                 printf("time set to ");
 106         }
 107         printf("%s: %s", argv[i], ctime(&unix_time));
 108         exit(0);
 109 }