source: vendor/3.5.0/source3/utils/net_time.c

/*
   Samba Unix/Linux SMB client library
   net time command
   Copyright (C) 2001 Andrew Tridgell (tridge@samba.org)

   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 3 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, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "utils/net.h"

/*
  return the time on a server. This does not require any authentication
*/
static time_t cli_servertime(const char *host, struct sockaddr_storage *pss, int *zone)
{
        struct nmb_name calling, called;
        time_t ret = 0;
        struct cli_state *cli = NULL;
        NTSTATUS status;

        cli = cli_initialise();
        if (!cli) {
                goto done;
        }

        status = cli_connect(cli, host, pss);
        if (!NT_STATUS_IS_OK(status)) {
                fprintf(stderr, _("Can't contact server %s. Error %s\n"),
                        host, nt_errstr(status));
                goto done;
        }

        make_nmb_name(&calling, global_myname(), 0x0);
        if (host) {
                make_nmb_name(&called, host, 0x20);
        } else {
                make_nmb_name(&called, "*SMBSERVER", 0x20);
        }

        if (!cli_session_request(cli, &calling, &called)) {
                fprintf(stderr, _("Session request failed\n"));
                goto done;
        }
        status = cli_negprot(cli);
        if (!NT_STATUS_IS_OK(status)) {
                fprintf(stderr, _("Protocol negotiation failed: %s\n"),
                        nt_errstr(status));
                goto done;
        }

        ret = cli->servertime;
        if (zone) *zone = cli->serverzone;

done:
        if (cli) {
                cli_shutdown(cli);
        }
        return ret;
}

/* find the servers time on the opt_host host */
static time_t nettime(struct net_context *c, int *zone)
{
        return cli_servertime(c->opt_host,
                              c->opt_have_ip? &c->opt_dest_ip : NULL, zone);
}

/* return a time as a string ready to be passed to /bin/date */
static const char *systime(time_t t)
{
        struct tm *tm;

        tm = localtime(&t);
        if (!tm) {
                return "unknown";
        }

        return talloc_asprintf(talloc_tos(), "%02d%02d%02d%02d%04d.%02d",
                               tm->tm_mon+1, tm->tm_mday, tm->tm_hour,
                               tm->tm_min, tm->tm_year + 1900, tm->tm_sec);
}

int net_time_usage(struct net_context *c, int argc, const char **argv)
{
        d_printf(_(
"net time\n\tdisplays time on a server\n\n"
"net time system\n\tdisplays time on a server in a format ready for /bin/date\n\n"
"net time set\n\truns /bin/date with the time from the server\n\n"
"net time zone\n\tdisplays the timezone in hours from GMT on the remote computer\n\n"
"\n"));
        net_common_flags_usage(c, argc, argv);
        return -1;
}

/* try to set the system clock using /bin/date */
static int net_time_set(struct net_context *c, int argc, const char **argv)
{
        time_t t = nettime(c, NULL);
        char *cmd;
        int result;

        if (t == 0) return -1;

        /* yes, I know this is cheesy. Use "net time system" if you want to
           roll your own. I'm putting this in as it works on a large number
           of systems and the user has a choice in whether its used or not */
        if (asprintf(&cmd, "/bin/date %s", systime(t)) == -1) {
                return -1;
        }
        result = system(cmd);
        if (result)
                d_fprintf(stderr, _("%s failed.  Error was (%s)\n"),
                        cmd, strerror(errno));
        free(cmd);

        return result;
}

/* display the time on a remote box in a format ready for /bin/date */
static int net_time_system(struct net_context *c, int argc, const char **argv)
{
        time_t t;

        if (c->display_usage) {
                d_printf(  "%s\n"
                           "net time system\n"
                           "    %s\n",
                         _("Usage:"),
                         _("Output remote time server time in a format "
                           "ready for /bin/date"));
                return 0;
        }

        t = nettime(c, NULL);
        if (t == 0) return -1;

        printf("%s\n", systime(t));

        return 0;
}

/* display the remote time server's offset to UTC */
static int net_time_zone(struct net_context *c, int argc, const char **argv)
{
        int zone = 0;
        int hours, mins;
        char zsign;
        time_t t;

        if (c->display_usage) {
                d_printf(  "%s\n"
                           "net time zone\n"
                           "   %s\n",
                         _("Usage:"),
                         _("Display the remote time server's offset to "
                           "UTC"));
                return 0;
        }

        t = nettime(c, &zone);

        if (t == 0) return -1;

        zsign = (zone > 0) ? '-' : '+';
        if (zone < 0) zone = -zone;

        zone /= 60;
        hours = zone / 60;
        mins = zone % 60;

        printf("%c%02d%02d\n", zsign, hours, mins);

        return 0;
}

/* display or set the time on a host */
int net_time(struct net_context *c, int argc, const char **argv)
{
        time_t t;
        struct functable func[] = {
                {
                        "system",
                        net_time_system,
                        NET_TRANSPORT_LOCAL,
                        N_("Display time ready for /bin/date"),
                        N_("net time system\n"
                           "    Display time ready for /bin/date")
                },
                {
                        "set",
                        net_time_set,
                        NET_TRANSPORT_LOCAL,
                        N_("Set the system time from time server"),
                        N_("net time set\n"
                           "    Set the system time from time server")
                },
                {
                        "zone",
                        net_time_zone,
                        NET_TRANSPORT_LOCAL,
                        N_("Display timezone offset from UTC"),
                        N_("net time zone\n"
                           "    Display timezone offset from UTC")
                },
                {NULL, NULL, 0, NULL, NULL}
        };

        if (argc != 0) {
                return net_run_function(c, argc, argv, "net time", func);
        }

        if (c->display_usage) {
                d_printf(  "%s\n"
                           "net time\n"
                           "    %s\n",
                         _("Usage:"),
                         _("Display the remote time server's time"));
                net_display_usage_from_functable(func);
                return 0;
        }

        if (!c->opt_host && !c->opt_have_ip &&
            !find_master_ip(c->opt_target_workgroup, &c->opt_dest_ip)) {
                d_fprintf(stderr, _("Could not locate a time server.  Try "
                                    "specifying a target host.\n"));
                net_time_usage(c, argc,argv);
                return -1;
        }

        /* default - print the time */
        t = cli_servertime(c->opt_host, c->opt_have_ip? &c->opt_dest_ip : NULL,
                           NULL);
        if (t == 0) return -1;

        d_printf("%s", ctime(&t));
        return 0;
}