fetchnews_check_date.c

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/* (C) Copyright 2003 - 2010 Matthias Andree. See COPYING for license. */
 
#include "leafnode.h"
 
#include <string.h>
 
#include "fetchnews.h"
#include "system.h"
#include "ln_log.h"
 
/* send DATE command to upstream server and complain if the clocks are
 * more than 15 minutes apart.
 */
void
check_date(const struct server *current_server)
{
    int reply;
    struct tm tm;
    time_t t, to;
    const int tolerate = 10;
    const char *lastline;
 
    strcpy(lineout, "DATE\r\n");
    putaline();
    reply = nntpreply(current_server);
    if (reply != 111) {
    /* upstream does not support the DATE command, so ignore */
    if (debugmode) {
        syslog(LOG_DEBUG, "check_date: %s: does not support DATE, "
            "reply %d, expected 111", current_server->name, reply);
    }
    return;
    }
 
    lastline = lastreply();
    if (lastline == NULL) {
    ln_log(LNLOG_SWARNING, LNLOG_CTOP,
        "%s: warning: server disconnect or timeout in response to DATE command",
        current_server->name);
    return;
    }
 
    /* upstream supports the DATE command */
    if (sscanf(lastline, "%*d %4d%2d%2d%2d%2d%2d",
        &tm.tm_year, &tm.tm_mon, &tm.tm_mday,
        &tm.tm_hour, &tm.tm_min, &tm.tm_sec) < 6) {
    /* too few fields */
    ln_log(LNLOG_SINFO, LNLOG_CSERVER, "%s: check_date: too few fields in successful DATE reply "
        "\"%s\"", current_server->name, lastline);
    return;
    }
 
    /* we can match 6 fields, parse date */
    tm.tm_year -= 1900;
    tm.tm_mon -= 1;
    tm.tm_isdst = -1; /* let libc figure time zone offset */
    t = timegm(&tm);
    if (t == (time_t) -1) {
    /* error, ignore */
    ln_log(LNLOG_SINFO, LNLOG_CSERVER, "%s: check_date: upstream sent unparsable reply "
        "to DATE, mktime failed. \"%s\"", current_server->name, lastline);
    return;
    }
 
    if (labs((long)(t - time(&to))) > tolerate * 60
#if SIZEOF_TIME_T >= SIZEOF_LONG
            || t - to > LONG_MAX || to - t > LONG_MAX
#endif
            ) {
    syslog(LOG_WARNING, "check_date: %s: clocks of upstream and this computer are more than %d minutes apart. Check your system clock.", current_server->name, tolerate);
    printf("check_date: %s: clocks of upstream and this computer are more than\n%d minutes apart. Check your system clock.\n", current_server->name, tolerate);
    } else {
    if (debugmode) {
        syslog(LOG_DEBUG, "check_date: %s: server time %ld, our time %ld",
            current_server->name, (long)t, (long)to);
    }
    }
}