diff options
Diffstat (limited to 'busybox/util-linux/rdate.c')
| -rw-r--r-- | busybox/util-linux/rdate.c | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/busybox/util-linux/rdate.c b/busybox/util-linux/rdate.c new file mode 100644 index 0000000..a73e8ee --- /dev/null +++ b/busybox/util-linux/rdate.c @@ -0,0 +1,121 @@ +/* vi: set sw=4 ts=4: */ +/* + * The Rdate command will ask a time server for the RFC 868 time + * and optionally set the system time. + * + * by Sterling Huxley <sterling@europa.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * +*/ + +#include <sys/time.h> +#include <sys/types.h> +#include <sys/socket.h> +#include <netinet/in.h> +#include <netdb.h> +#include <stdio.h> +#include <getopt.h> +#include <string.h> +#include <time.h> +#include <stdlib.h> +#include <unistd.h> +#include <signal.h> + +#include "busybox.h" + + +static const int RFC_868_BIAS = 2208988800UL; + +static void socket_timeout(int sig) +{ + bb_error_msg_and_die("timeout connecting to time server"); +} + +static time_t askremotedate(const char *host) +{ + unsigned long int nett, localt; + struct sockaddr_in s_in; + int fd; + + bb_lookup_host(&s_in, host); + s_in.sin_port = bb_lookup_port("time", "tcp", 37); + + /* Add a timeout for dead or non accessable servers */ + alarm(10); + signal(SIGALRM, socket_timeout); + + fd = xconnect(&s_in); + + if (safe_read(fd, (void *)&nett, 4) != 4) /* read time from server */ + bb_error_msg_and_die("%s did not send the complete time", host); + + close(fd); + + /* convert from network byte order to local byte order. + * RFC 868 time is the number of seconds + * since 00:00 (midnight) 1 January 1900 GMT + * the RFC 868 time 2,208,988,800 corresponds to 00:00 1 Jan 1970 GMT + * Subtract the RFC 868 time to get Linux epoch + */ + localt= ntohl(nett) - RFC_868_BIAS; + + return(localt); +} + +int rdate_main(int argc, char **argv) +{ + time_t remote_time; + int opt; + int setdate = 1; + int printdate = 1; + + /* Interpret command line args */ + while ((opt = getopt(argc, argv, "sp")) > 0) { + switch (opt) { + case 's': + printdate = 0; + setdate = 1; + break; + case 'p': + printdate = 1; + setdate = 0; + break; + default: + bb_show_usage(); + } + } + + if (optind == argc) + bb_show_usage(); + + remote_time = askremotedate(argv[optind]); + + if (setdate) { + time_t current_time; + + time(¤t_time); + if (current_time == remote_time) + bb_error_msg("Current time matches remote time."); + else + if (stime(&remote_time) < 0) + bb_perror_msg_and_die("Could not set time of day"); + } + + if (printdate) + printf("%s", ctime(&remote_time)); + + return EXIT_SUCCESS; +} |