auth:tests: Only enable torture_gnutls_aes_128_cfb() on GnuTLS >= 3.6.11

[Samba.git] / lib / util / time.c

/* 
   Unix SMB/CIFS implementation.
   time handling functions

   Copyright (C) Andrew Tridgell                1992-2004
   Copyright (C) Stefan (metze) Metzmacher      2002   
   Copyright (C) Jeremy Allison                 2007
   Copyright (C) Andrew Bartlett                2011

   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 "replace.h"
#include "system/time.h"
#include "byteorder.h"
#include "time_basic.h"
#include "lib/util/time.h" /* Avoid /usr/include/time.h */

/**
 * @file
 * @brief time handling functions
 */

#if (SIZEOF_LONG == 8)
#define TIME_FIXUP_CONSTANT_INT 11644473600L
#elif (SIZEOF_LONG_LONG == 8)
#define TIME_FIXUP_CONSTANT_INT 11644473600LL
#endif



/**
 External access to time_t_min and time_t_max.
**/
_PUBLIC_ time_t get_time_t_max(void)
{
        return TIME_T_MAX;
}

/**
a wrapper to preferably get the monotonic time
**/
_PUBLIC_ void clock_gettime_mono(struct timespec *tp)
{
/* prefer a suspend aware monotonic CLOCK_BOOTTIME: */
#ifdef CLOCK_BOOTTIME
        if (clock_gettime(CLOCK_BOOTTIME,tp) == 0) {
                return;
        }
#endif
/* then try the  monotonic clock: */
#ifndef CUSTOM_CLOCK_MONOTONIC_IS_REALTIME
        if (clock_gettime(CUSTOM_CLOCK_MONOTONIC,tp) == 0) {
                return;
        }
#endif
        clock_gettime(CLOCK_REALTIME,tp);
}

/**
a wrapper to preferably get the monotonic time in seconds
**/
_PUBLIC_ time_t time_mono(time_t *t)
{
        struct timespec tp;

        clock_gettime_mono(&tp);
        if (t != NULL) {
                *t = tp.tv_sec;
        }
        return tp.tv_sec;
}


#define TIME_FIXUP_CONSTANT 11644473600LL

time_t convert_timespec_to_time_t(struct timespec ts)
{
        /* Ensure tv_nsec is less than 1sec. */
        while (ts.tv_nsec > 1000000000) {
                ts.tv_sec += 1;
                ts.tv_nsec -= 1000000000;
        }

        /* 1 ns == 1,000,000,000 - one thousand millionths of a second.
           increment if it's greater than 500 millionth of a second. */

        if (ts.tv_nsec > 500000000) {
                return ts.tv_sec + 1;
        }
        return ts.tv_sec;
}

struct timespec convert_time_t_to_timespec(time_t t)
{
        struct timespec ts;
        ts.tv_sec = t;
        ts.tv_nsec = 0;
        return ts;
}



/**
 Interpret an 8 byte "filetime" structure to a time_t
 It's originally in "100ns units since jan 1st 1601"

 An 8 byte value of 0xffffffffffffffff will be returned as a timespec of

        tv_sec = 0
        tv_nsec = 0;

 Returns GMT.
**/
time_t nt_time_to_unix(NTTIME nt)
{
        return convert_timespec_to_time_t(nt_time_to_unix_timespec(nt));
}


/**
put a 8 byte filetime from a time_t
This takes GMT as input
**/
_PUBLIC_ void unix_to_nt_time(NTTIME *nt, time_t t)
{
        uint64_t t2; 

        if (t == (time_t)-1) {
                *nt = (NTTIME)-1LL;
                return;
        }       

        if (t == TIME_T_MAX || t == INT64_MAX) {
                *nt = 0x7fffffffffffffffLL;
                return;
        }

        if (t == 0) {
                *nt = 0;
                return;
        }               

        t2 = t;
        t2 += TIME_FIXUP_CONSTANT_INT;
        t2 *= 1000*1000*10;

        *nt = t2;
}


/**
check if it's a null unix time
**/
_PUBLIC_ bool null_time(time_t t)
{
        return t == 0 || 
                t == (time_t)0xFFFFFFFF || 
                t == (time_t)-1;
}


/**
check if it's a null NTTIME
**/
_PUBLIC_ bool null_nttime(NTTIME t)
{
        return t == 0 || t == (NTTIME)-1;
}

/*******************************************************************
  create a 16 bit dos packed date
********************************************************************/
static uint16_t make_dos_date1(struct tm *t)
{
        uint16_t ret=0;
        ret = (((unsigned int)(t->tm_mon+1)) >> 3) | ((t->tm_year-80) << 1);
        ret = ((ret&0xFF)<<8) | (t->tm_mday | (((t->tm_mon+1) & 0x7) << 5));
        return ret;
}

/*******************************************************************
  create a 16 bit dos packed time
********************************************************************/
static uint16_t make_dos_time1(struct tm *t)
{
        uint16_t ret=0;
        ret = ((((unsigned int)t->tm_min >> 3)&0x7) | (((unsigned int)t->tm_hour) << 3));
        ret = ((ret&0xFF)<<8) | ((t->tm_sec/2) | ((t->tm_min & 0x7) << 5));
        return ret;
}

/*******************************************************************
  create a 32 bit dos packed date/time from some parameters
  This takes a GMT time and returns a packed localtime structure
********************************************************************/
static uint32_t make_dos_date(time_t unixdate, int zone_offset)
{
        struct tm *t;
        uint32_t ret=0;

        if (unixdate == 0) {
                return 0;
        }

        unixdate -= zone_offset;

        t = gmtime(&unixdate);
        if (!t) {
                return 0xFFFFFFFF;
        }

        ret = make_dos_date1(t);
        ret = ((ret&0xFFFF)<<16) | make_dos_time1(t);

        return ret;
}

/**
put a dos date into a buffer (time/date format)
This takes GMT time and puts local time in the buffer
**/
_PUBLIC_ void push_dos_date(uint8_t *buf, int offset, time_t unixdate, int zone_offset)
{
        uint32_t x = make_dos_date(unixdate, zone_offset);
        SIVAL(buf,offset,x);
}

/**
put a dos date into a buffer (date/time format)
This takes GMT time and puts local time in the buffer
**/
_PUBLIC_ void push_dos_date2(uint8_t *buf,int offset,time_t unixdate, int zone_offset)
{
        uint32_t x;
        x = make_dos_date(unixdate, zone_offset);
        x = ((x&0xFFFF)<<16) | ((x&0xFFFF0000)>>16);
        SIVAL(buf,offset,x);
}

/**
put a dos 32 bit "unix like" date into a buffer. This routine takes
GMT and converts it to LOCAL time before putting it (most SMBs assume
localtime for this sort of date)
**/
_PUBLIC_ void push_dos_date3(uint8_t *buf,int offset,time_t unixdate, int zone_offset)
{
        if (!null_time(unixdate)) {
                unixdate -= zone_offset;
        }
        SIVAL(buf,offset,unixdate);
}

/*******************************************************************
  interpret a 32 bit dos packed date/time to some parameters
********************************************************************/
void interpret_dos_date(uint32_t date,int *year,int *month,int *day,int *hour,int *minute,int *second)
{
        uint32_t p0,p1,p2,p3;

        p0=date&0xFF; p1=((date&0xFF00)>>8)&0xFF; 
        p2=((date&0xFF0000)>>16)&0xFF; p3=((date&0xFF000000)>>24)&0xFF;

        *second = 2*(p0 & 0x1F);
        *minute = ((p0>>5)&0xFF) + ((p1&0x7)<<3);
        *hour = (p1>>3)&0xFF;
        *day = (p2&0x1F);
        *month = ((p2>>5)&0xFF) + ((p3&0x1)<<3) - 1;
        *year = ((p3>>1)&0xFF) + 80;
}

/**
  create a unix date (int GMT) from a dos date (which is actually in
  localtime)
**/
_PUBLIC_ time_t pull_dos_date(const uint8_t *date_ptr, int zone_offset)
{
        uint32_t dos_date=0;
        struct tm t;
        time_t ret;

        dos_date = IVAL(date_ptr,0);

        if (dos_date == 0) return (time_t)0;
  
        interpret_dos_date(dos_date,&t.tm_year,&t.tm_mon,
                           &t.tm_mday,&t.tm_hour,&t.tm_min,&t.tm_sec);
        t.tm_isdst = -1;
  
        ret = timegm(&t);

        ret += zone_offset;

        return ret;
}

/**
like make_unix_date() but the words are reversed
**/
_PUBLIC_ time_t pull_dos_date2(const uint8_t *date_ptr, int zone_offset)
{
        uint32_t x,x2;

        x = IVAL(date_ptr,0);
        x2 = ((x&0xFFFF)<<16) | ((x&0xFFFF0000)>>16);
        SIVAL(&x,0,x2);

        return pull_dos_date((const uint8_t *)&x, zone_offset);
}

/**
  create a unix GMT date from a dos date in 32 bit "unix like" format
  these generally arrive as localtimes, with corresponding DST
**/
_PUBLIC_ time_t pull_dos_date3(const uint8_t *date_ptr, int zone_offset)
{
        time_t t = (time_t)IVAL(date_ptr,0);

        if (t == (time_t)0xFFFFFFFF) {
                t = (time_t)-1;
        }

        if (!null_time(t)) {
                t += zone_offset;
        }
        return t;
}

/****************************************************************************
 Return the date and time as a string
****************************************************************************/

char *timeval_string(TALLOC_CTX *ctx, const struct timeval *tp, bool hires)
{
        struct timeval_buf tmp;
        char *result;

        result = talloc_strdup(ctx, timeval_str_buf(tp, false, hires, &tmp));
        if (result == NULL) {
                return NULL;
        }

        /*
         * beautify the talloc_report output
         *
         * This is not just cosmetics. A C compiler might in theory make the
         * talloc_strdup call above a tail call with the tail call
         * optimization. This would render "tmp" invalid while talloc_strdup
         * tries to duplicate it. The talloc_set_name_const call below puts
         * the talloc_strdup call into non-tail position.
         */
        talloc_set_name_const(result, result);
        return result;
}

/****************************************************************************
 Return the date and time as a string
****************************************************************************/

const char *timespec_string_buf(const struct timespec *tp,
                                bool hires,
                                struct timeval_buf *buf)
{
        time_t t;
        struct tm *tm = NULL;
        size_t len;

        if (is_omit_timespec(tp)) {
                strlcpy(buf->buf, "SAMBA_UTIME_OMIT", sizeof(buf->buf));
                return buf->buf;
        }

        t = (time_t)tp->tv_sec;
        tm = localtime(&t);

        if (tm == NULL) {
                if (hires) {
                        len = snprintf(buf->buf, sizeof(buf->buf),
                                       "%ld.%09ld seconds since the Epoch",
                                       (long)tp->tv_sec, (long)tp->tv_nsec);
                } else {
                        len = snprintf(buf->buf, sizeof(buf->buf),
                                       "%ld seconds since the Epoch", (long)t);
                }
        } else if (!hires) {
                len = snprintf(buf->buf, sizeof(buf->buf),
                               "%04d/%02d/%02d %02d:%02d:%02d",
                               1900 + tm->tm_year,
                               tm->tm_mon + 1,
                               tm->tm_mday,
                               tm->tm_hour,
                               tm->tm_min,
                               tm->tm_sec);
        } else {
                len = snprintf(buf->buf, sizeof(buf->buf),
                               "%04d/%02d/%02d %02d:%02d:%02d.%09ld",
                               1900 + tm->tm_year,
                               tm->tm_mon + 1,
                               tm->tm_mday,
                               tm->tm_hour,
                               tm->tm_min,
                               tm->tm_sec,
                               (long)tp->tv_nsec);
        }
        if (len == -1) {
                return "";
        }

        return buf->buf;
}

char *current_timestring(TALLOC_CTX *ctx, bool hires)
{
        struct timeval tv;

        GetTimeOfDay(&tv);
        return timeval_string(ctx, &tv, hires);
}

/*
 * Return date and time as a minimal string avoiding funny characters
 * that may cause trouble in file names. We only use digits and
 * underscore ... or a minus/hyphen if we got negative time.
 */
char *minimal_timeval_string(TALLOC_CTX *ctx, const struct timeval *tp, bool hires)
{
        time_t t;
        struct tm *tm;

        t = (time_t)tp->tv_sec;
        tm = localtime(&t);
        if (!tm) {
                if (hires) {
                        return talloc_asprintf(ctx, "%ld_%06ld",
                                               (long)tp->tv_sec,
                                               (long)tp->tv_usec);
                } else {
                        return talloc_asprintf(ctx, "%ld", (long)t);
                }
        } else {
                if (hires) {
                        return talloc_asprintf(ctx,
                                               "%04d%02d%02d_%02d%02d%02d_%06ld",
                                               tm->tm_year+1900,
                                               tm->tm_mon+1,
                                               tm->tm_mday,
                                               tm->tm_hour,
                                               tm->tm_min,
                                               tm->tm_sec,
                                               (long)tp->tv_usec);
                } else {
                        return talloc_asprintf(ctx,
                                               "%04d%02d%02d_%02d%02d%02d",
                                               tm->tm_year+1900,
                                               tm->tm_mon+1,
                                               tm->tm_mday,
                                               tm->tm_hour,
                                               tm->tm_min,
                                               tm->tm_sec);
                }
        }
}

char *current_minimal_timestring(TALLOC_CTX *ctx, bool hires)
{
        struct timeval tv;

        GetTimeOfDay(&tv);
        return minimal_timeval_string(ctx, &tv, hires);
}

/**
return a HTTP/1.0 time string
**/
_PUBLIC_ char *http_timestring(TALLOC_CTX *mem_ctx, time_t t)
{
        char *buf;
        char tempTime[60];
        struct tm *tm = localtime(&t);

        if (t == TIME_T_MAX) {
                return talloc_strdup(mem_ctx, "never");
        }

        if (!tm) {
                return talloc_asprintf(mem_ctx,"%ld seconds since the Epoch",(long)t);
        }

#ifndef HAVE_STRFTIME
        buf = talloc_strdup(mem_ctx, asctime(tm));
        if (buf[strlen(buf)-1] == '\n') {
                buf[strlen(buf)-1] = 0;
        }
#else
        strftime(tempTime, sizeof(tempTime)-1, "%a, %d %b %Y %H:%M:%S %Z", tm);
        buf = talloc_strdup(mem_ctx, tempTime);
#endif /* !HAVE_STRFTIME */

        return buf;
}

/**
 Return the date and time as a string
**/
_PUBLIC_ char *timestring(TALLOC_CTX *mem_ctx, time_t t)
{
        char *TimeBuf;
        char tempTime[80];
        struct tm *tm;

        tm = localtime(&t);
        if (!tm) {
                return talloc_asprintf(mem_ctx,
                                       "%ld seconds since the Epoch",
                                       (long)t);
        }

#ifdef HAVE_STRFTIME
        /* Some versions of gcc complain about using some special format
         * specifiers. This is a bug in gcc, not a bug in this code. See a
         * recent strftime() manual page for details. */
        strftime(tempTime,sizeof(tempTime)-1,"%a %b %e %X %Y %Z",tm);
        TimeBuf = talloc_strdup(mem_ctx, tempTime);
#else
        TimeBuf = talloc_strdup(mem_ctx, asctime(tm));
        if (TimeBuf == NULL) {
                return NULL;
        }
        if (TimeBuf[0] != '\0') {
                size_t len = strlen(TimeBuf);
                if (TimeBuf[len - 1] == '\n') {
                        TimeBuf[len - 1] = '\0';
                }
        }
#endif

        return TimeBuf;
}

/**
  return a talloced string representing a NTTIME for human consumption
*/
_PUBLIC_ const char *nt_time_string(TALLOC_CTX *mem_ctx, NTTIME nt)
{
        time_t t;
        if (nt == 0) {
                return "NTTIME(0)";
        }
        t = nt_time_to_full_time_t(nt);
        return timestring(mem_ctx, t);
}


/**
  put a NTTIME into a packet
*/
_PUBLIC_ void push_nttime(uint8_t *base, uint16_t offset, NTTIME t)
{
        SBVAL(base, offset,   t);
}

/**
  pull a NTTIME from a packet
*/
_PUBLIC_ NTTIME pull_nttime(uint8_t *base, uint16_t offset)
{
        NTTIME ret = BVAL(base, offset);
        return ret;
}

/**
  return (tv1 - tv2) in microseconds
*/
_PUBLIC_ int64_t usec_time_diff(const struct timeval *tv1, const struct timeval *tv2)
{
        int64_t sec_diff = tv1->tv_sec - tv2->tv_sec;
        return (sec_diff * 1000000) + (int64_t)(tv1->tv_usec - tv2->tv_usec);
}

/**
  return (tp1 - tp2) in nanoseconds
*/
_PUBLIC_ int64_t nsec_time_diff(const struct timespec *tp1, const struct timespec *tp2)
{
        int64_t sec_diff = tp1->tv_sec - tp2->tv_sec;
        return (sec_diff * 1000000000) + (int64_t)(tp1->tv_nsec - tp2->tv_nsec);
}


/**
  return a zero timeval
*/
_PUBLIC_ struct timeval timeval_zero(void)
{
        struct timeval tv;
        tv.tv_sec = 0;
        tv.tv_usec = 0;
        return tv;
}

/**
  return true if a timeval is zero
*/
_PUBLIC_ bool timeval_is_zero(const struct timeval *tv)
{
        return tv->tv_sec == 0 && tv->tv_usec == 0;
}

/**
  return a timeval for the current time
*/
_PUBLIC_ struct timeval timeval_current(void)
{
        struct timeval tv;
        GetTimeOfDay(&tv);
        return tv;
}

/**
  return a timeval struct with the given elements
*/
_PUBLIC_ struct timeval timeval_set(uint32_t secs, uint32_t usecs)
{
        struct timeval tv;
        tv.tv_sec = secs;
        tv.tv_usec = usecs;
        return tv;
}


/**
  return a timeval ofs microseconds after tv
*/
_PUBLIC_ struct timeval timeval_add(const struct timeval *tv,
                           uint32_t secs, uint32_t usecs)
{
        struct timeval tv2 = *tv;
        const unsigned int million = 1000000;
        tv2.tv_sec += secs;
        tv2.tv_usec += usecs;
        tv2.tv_sec += tv2.tv_usec / million;
        tv2.tv_usec = tv2.tv_usec % million;
        return tv2;
}

/**
  return the sum of two timeval structures
*/
struct timeval timeval_sum(const struct timeval *tv1,
                           const struct timeval *tv2)
{
        return timeval_add(tv1, tv2->tv_sec, tv2->tv_usec);
}

/**
  return a timeval secs/usecs into the future
*/
_PUBLIC_ struct timeval timeval_current_ofs(uint32_t secs, uint32_t usecs)
{
        struct timeval tv = timeval_current();
        return timeval_add(&tv, secs, usecs);
}

/**
  return a timeval milliseconds into the future
*/
_PUBLIC_ struct timeval timeval_current_ofs_msec(uint32_t msecs)
{
        struct timeval tv = timeval_current();
        return timeval_add(&tv, msecs / 1000, (msecs % 1000) * 1000);
}

/**
  return a timeval microseconds into the future
*/
_PUBLIC_ struct timeval timeval_current_ofs_usec(uint32_t usecs)
{
        struct timeval tv = timeval_current();
        return timeval_add(&tv, usecs / 1000000, usecs % 1000000);
}

/**
  compare two timeval structures. 
  Return -1 if tv1 < tv2
  Return 0 if tv1 == tv2
  Return 1 if tv1 > tv2
*/
_PUBLIC_ int timeval_compare(const struct timeval *tv1, const struct timeval *tv2)
{
        if (tv1->tv_sec  > tv2->tv_sec)  return 1;
        if (tv1->tv_sec  < tv2->tv_sec)  return -1;
        if (tv1->tv_usec > tv2->tv_usec) return 1;
        if (tv1->tv_usec < tv2->tv_usec) return -1;
        return 0;
}

/**
  return true if a timer is in the past
*/
_PUBLIC_ bool timeval_expired(const struct timeval *tv)
{
        struct timeval tv2 = timeval_current();
        if (tv2.tv_sec > tv->tv_sec) return true;
        if (tv2.tv_sec < tv->tv_sec) return false;
        return (tv2.tv_usec >= tv->tv_usec);
}

/**
  return the number of seconds elapsed between two times
*/
_PUBLIC_ double timeval_elapsed2(const struct timeval *tv1, const struct timeval *tv2)
{
        return (tv2->tv_sec - tv1->tv_sec) + 
               (tv2->tv_usec - tv1->tv_usec)*1.0e-6;
}

/**
  return the number of seconds elapsed since a given time
*/
_PUBLIC_ double timeval_elapsed(const struct timeval *tv)
{
        struct timeval tv2 = timeval_current();
        return timeval_elapsed2(tv, &tv2);
}
/**
 *   return the number of seconds elapsed between two times
 **/
_PUBLIC_ double timespec_elapsed2(const struct timespec *ts1,
                                const struct timespec *ts2)
{
        return (ts2->tv_sec - ts1->tv_sec) +
               (ts2->tv_nsec - ts1->tv_nsec)*1.0e-9;
}

/**
 *   return the number of seconds elapsed since a given time
 */
_PUBLIC_ double timespec_elapsed(const struct timespec *ts)
{
        struct timespec ts2 = timespec_current();
        return timespec_elapsed2(ts, &ts2);
}

/**
  return the lesser of two timevals
*/
_PUBLIC_ struct timeval timeval_min(const struct timeval *tv1,
                           const struct timeval *tv2)
{
        if (tv1->tv_sec < tv2->tv_sec) return *tv1;
        if (tv1->tv_sec > tv2->tv_sec) return *tv2;
        if (tv1->tv_usec < tv2->tv_usec) return *tv1;
        return *tv2;
}

/**
  return the greater of two timevals
*/
_PUBLIC_ struct timeval timeval_max(const struct timeval *tv1,
                           const struct timeval *tv2)
{
        if (tv1->tv_sec > tv2->tv_sec) return *tv1;
        if (tv1->tv_sec < tv2->tv_sec) return *tv2;
        if (tv1->tv_usec > tv2->tv_usec) return *tv1;
        return *tv2;
}

/**
  return the difference between two timevals as a timeval
  if tv1 comes after tv2, then return a zero timeval
  (this is *tv2 - *tv1)
*/
_PUBLIC_ struct timeval timeval_until(const struct timeval *tv1,
                             const struct timeval *tv2)
{
        struct timeval t;
        if (timeval_compare(tv1, tv2) >= 0) {
                return timeval_zero();
        }
        t.tv_sec = tv2->tv_sec - tv1->tv_sec;
        if (tv1->tv_usec > tv2->tv_usec) {
                t.tv_sec--;
                t.tv_usec = 1000000 - (tv1->tv_usec - tv2->tv_usec);
        } else {
                t.tv_usec = tv2->tv_usec - tv1->tv_usec;
        }
        return t;
}


/**
  convert a timeval to a NTTIME
*/
_PUBLIC_ NTTIME timeval_to_nttime(const struct timeval *tv)
{
        return 10*(tv->tv_usec + 
                  ((TIME_FIXUP_CONSTANT + (uint64_t)tv->tv_sec) * 1000000));
}

/**
  convert a NTTIME to a timeval
*/
_PUBLIC_ void nttime_to_timeval(struct timeval *tv, NTTIME t)
{
        if (tv == NULL) return;

        t += 10/2;
        t /= 10;
        t -= TIME_FIXUP_CONSTANT*1000*1000;

        tv->tv_sec  = t / 1000000;

        if (TIME_T_MIN > tv->tv_sec || tv->tv_sec > TIME_T_MAX) {
                tv->tv_sec  = 0;
                tv->tv_usec = 0;
                return;
        }
        
        tv->tv_usec = t - tv->tv_sec*1000000;
}

/*******************************************************************
yield the difference between *A and *B, in seconds, ignoring leap seconds
********************************************************************/
static int tm_diff(struct tm *a, struct tm *b)
{
        int ay = a->tm_year + (1900 - 1);
        int by = b->tm_year + (1900 - 1);
        int intervening_leap_days =
                (ay/4 - by/4) - (ay/100 - by/100) + (ay/400 - by/400);
        int years = ay - by;
        int days = 365*years + intervening_leap_days + (a->tm_yday - b->tm_yday);
        int hours = 24*days + (a->tm_hour - b->tm_hour);
        int minutes = 60*hours + (a->tm_min - b->tm_min);
        int seconds = 60*minutes + (a->tm_sec - b->tm_sec);

        return seconds;
}


/**
  return the UTC offset in seconds west of UTC, or 0 if it cannot be determined
 */
_PUBLIC_ int get_time_zone(time_t t)
{
        struct tm *tm = gmtime(&t);
        struct tm tm_utc;
        if (!tm)
                return 0;
        tm_utc = *tm;
        tm = localtime(&t);
        if (!tm)
                return 0;
        return tm_diff(&tm_utc,tm);
}

struct timespec nt_time_to_unix_timespec(NTTIME nt)
{
        int64_t d;
        struct timespec ret;

        if (nt == 0 || nt == (int64_t)-1) {
                ret.tv_sec = 0;
                ret.tv_nsec = 0;
                return ret;
        }

        d = (int64_t)nt;
        /* d is now in 100ns units, since jan 1st 1601".
           Save off the ns fraction. */

        /*
         * Take the last seven decimal digits and multiply by 100.
         * to convert from 100ns units to 1ns units.
         */
        ret.tv_nsec = (long) ((d % (1000 * 1000 * 10)) * 100);

        /* Convert to seconds */
        d /= 1000*1000*10;

        /* Now adjust by 369 years to make the secs since 1970 */
        d -= TIME_FIXUP_CONSTANT_INT;

        if (d <= (int64_t)TIME_T_MIN) {
                ret.tv_sec = TIME_T_MIN;
                ret.tv_nsec = 0;
                return ret;
        }

        if (d >= (int64_t)TIME_T_MAX) {
                ret.tv_sec = TIME_T_MAX;
                ret.tv_nsec = 0;
                return ret;
        }

        ret.tv_sec = (time_t)d;
        return ret;
}


/**
  check if 2 NTTIMEs are equal.
*/
bool nt_time_equal(NTTIME *t1, NTTIME *t2)
{
        return *t1 == *t2;
}

/**
 Check if it's a null timespec.
**/

bool null_timespec(struct timespec ts)
{
        return ts.tv_sec == 0 || 
                ts.tv_sec == (time_t)0xFFFFFFFF || 
                ts.tv_sec == (time_t)-1;
}

/****************************************************************************
 Convert a normalized timeval to a timespec.
****************************************************************************/

struct timespec convert_timeval_to_timespec(const struct timeval tv)
{
        struct timespec ts;
        ts.tv_sec = tv.tv_sec;
        ts.tv_nsec = tv.tv_usec * 1000;
        return ts;
}

/****************************************************************************
 Convert a normalized timespec to a timeval.
****************************************************************************/

struct timeval convert_timespec_to_timeval(const struct timespec ts)
{
        struct timeval tv;
        tv.tv_sec = ts.tv_sec;
        tv.tv_usec = ts.tv_nsec / 1000;
        return tv;
}

/****************************************************************************
 Return a timespec for the current time
****************************************************************************/

_PUBLIC_ struct timespec timespec_current(void)
{
        struct timespec ts;
        clock_gettime(CLOCK_REALTIME, &ts);
        return ts;
}

/****************************************************************************
 Return the lesser of two timespecs.
****************************************************************************/

struct timespec timespec_min(const struct timespec *ts1,
                           const struct timespec *ts2)
{
        if (ts1->tv_sec < ts2->tv_sec) return *ts1;
        if (ts1->tv_sec > ts2->tv_sec) return *ts2;
        if (ts1->tv_nsec < ts2->tv_nsec) return *ts1;
        return *ts2;
}

/****************************************************************************
  compare two timespec structures. 
  Return -1 if ts1 < ts2
  Return 0 if ts1 == ts2
  Return 1 if ts1 > ts2
****************************************************************************/

_PUBLIC_ int timespec_compare(const struct timespec *ts1, const struct timespec *ts2)
{
        if (ts1->tv_sec  > ts2->tv_sec)  return 1;
        if (ts1->tv_sec  < ts2->tv_sec)  return -1;
        if (ts1->tv_nsec > ts2->tv_nsec) return 1;
        if (ts1->tv_nsec < ts2->tv_nsec) return -1;
        return 0;
}

/****************************************************************************
 Round up a timespec if nsec > 500000000, round down if lower,
 then zero nsec.
****************************************************************************/

void round_timespec_to_sec(struct timespec *ts)
{
        ts->tv_sec = convert_timespec_to_time_t(*ts);
        ts->tv_nsec = 0;
}

/****************************************************************************
 Round a timespec to usec value.
****************************************************************************/

void round_timespec_to_usec(struct timespec *ts)
{
        struct timeval tv = convert_timespec_to_timeval(*ts);
        *ts = convert_timeval_to_timespec(tv);
        while (ts->tv_nsec > 1000000000) {
                ts->tv_sec += 1;
                ts->tv_nsec -= 1000000000;
        }
}

/****************************************************************************
 Round a timespec to NTTIME resolution.
****************************************************************************/

void round_timespec_to_nttime(struct timespec *ts)
{
        ts->tv_nsec = (ts->tv_nsec / 100) * 100;
}

/****************************************************************************
 Put a 8 byte filetime from a struct timespec. Uses GMT.
****************************************************************************/

_PUBLIC_ NTTIME unix_timespec_to_nt_time(struct timespec ts)
{
        uint64_t d;

        if (ts.tv_sec ==0 && ts.tv_nsec == 0) {
                return 0;
        }
        if (ts.tv_sec == TIME_T_MAX) {
                return 0x7fffffffffffffffLL;
        }
        if (ts.tv_sec == (time_t)-1) {
                return (uint64_t)-1;
        }

        d = ts.tv_sec;
        d += TIME_FIXUP_CONSTANT_INT;
        d *= 1000*1000*10;
        /* d is now in 100ns units. */
        d += (ts.tv_nsec / 100);

        return d;
}

/*
 * Functions supporting the full range of time_t and struct timespec values,
 * including 0, -1 and all other negative values. These functions don't use 0 or
 * -1 values as sentinel to denote "unset" variables, but use the POSIX 2008
 * define UTIME_OMIT from utimensat(2).
 */

/**
 * Check if it's a to be omitted timespec.
 **/
bool is_omit_timespec(const struct timespec *ts)
{
        return ts->tv_nsec == SAMBA_UTIME_OMIT;
}

/**
 * Return a to be omitted timespec.
 **/
struct timespec make_omit_timespec(void)
{
        return (struct timespec){.tv_nsec = SAMBA_UTIME_OMIT};
}

/**
 * Like unix_timespec_to_nt_time() but without the special casing of tv_sec=0
 * and -1. Also dealing with SAMBA_UTIME_OMIT.
 **/
NTTIME full_timespec_to_nt_time(const struct timespec *_ts)
{
        struct timespec ts = *_ts;
        uint64_t d;

        if (is_omit_timespec(_ts)) {
                return NTTIME_OMIT;
        }

        /* Ensure tv_nsec is less than 1 sec. */
        while (ts.tv_nsec > 1000000000) {
                if (ts.tv_sec > TIME_T_MAX) {
                        return NTTIME_MAX;
                }
                ts.tv_sec += 1;
                ts.tv_nsec -= 1000000000;
        }

        if (ts.tv_sec >= TIME_T_MAX) {
                return NTTIME_MAX;
        }
        if ((ts.tv_sec + TIME_FIXUP_CONSTANT_INT) <= 0) {
                return NTTIME_MIN;
        }

        d = TIME_FIXUP_CONSTANT_INT;
        d += ts.tv_sec;

        d *= 1000*1000*10;
        /* d is now in 100ns units. */
        d += (ts.tv_nsec / 100);

        return d;
}

/**
 * Like nt_time_to_unix_timespec() but allowing negative tv_sec values and
 * returning NTTIME=0 and -1 as struct timespec {.tv_nsec = SAMBA_UTIME_OMIT}.
 *
 * See also: is_omit_timespec().
 **/
struct timespec nt_time_to_full_timespec(NTTIME nt)
{
        int64_t d;
        struct timespec ret;

        if (nt == NTTIME_OMIT) {
                return make_omit_timespec();
        }
        if (nt == NTTIME_FREEZE) {
                /*
                 * This should be returned as SAMBA_UTIME_FREEZE in the
                 * future.
                 */
                return make_omit_timespec();
        }
        if (nt > NTTIME_MAX) {
                nt = NTTIME_MAX;
        }

        d = (int64_t)nt;
        /* d is now in 100ns units, since jan 1st 1601".
           Save off the ns fraction. */

        /*
         * Take the last seven decimal digits and multiply by 100.
         * to convert from 100ns units to 1ns units.
         */
        ret.tv_nsec = (long) ((d % (1000 * 1000 * 10)) * 100);

        /* Convert to seconds */
        d /= 1000*1000*10;

        /* Now adjust by 369 years to make the secs since 1970 */
        d -= TIME_FIXUP_CONSTANT_INT;

        if (d >= (int64_t)TIME_T_MAX) {
                ret.tv_sec = TIME_T_MAX;
                ret.tv_nsec = 0;
                return ret;
        }

        ret.tv_sec = (time_t)d;
        return ret;
}

/**
 * Note: this function uses the full time_t range as valid date values including
 * (time_t)0 and -1. That means that struct timespec sentinel values (cf
 * is_omit_timespec()) can't be converted to sentinel values in a time_t
 * representation. Callers should therefor check the NTTIME value with
 * null_nttime() before calling this function.
 **/
time_t full_timespec_to_time_t(const struct timespec *_ts)
{
        struct timespec ts = *_ts;

        if (is_omit_timespec(_ts)) {
                /*
                 * Unfortunately there's no sensible sentinel value in the
                 * time_t range that is not conflicting with a valid time value
                 * ((time_t)0 and -1 are valid time values). Bite the bullit and
                 * return 0.
                 */
                return 0;
        }

        /* Ensure tv_nsec is less than 1sec. */
        while (ts.tv_nsec > 1000000000) {
                ts.tv_sec += 1;
                ts.tv_nsec -= 1000000000;
        }

        /* 1 ns == 1,000,000,000 - one thousand millionths of a second.
           increment if it's greater than 500 millionth of a second. */

        if (ts.tv_nsec > 500000000) {
                return ts.tv_sec + 1;
        }
        return ts.tv_sec;
}

/**
 * Like nt_time_to_unix() but supports negative time_t values.
 *
 * Note: this function uses the full time_t range as valid date values including
 * (time_t)0 and -1. That means that NTTIME sentinel values of 0 and -1 which
 * represent a "not-set" value, can't be converted to sentinel values in a
 * time_t representation. Callers should therefor check the NTTIME value with
 * null_nttime() before calling this function.
 **/
time_t nt_time_to_full_time_t(NTTIME nt)
{
        struct timespec ts;

        ts = nt_time_to_full_timespec(nt);
        return full_timespec_to_time_t(&ts);
}

/**
 * Like time_t_to_unix_timespec() but supports negative time_t values.
 *
 * This version converts (time_t)0 and -1 to an is_omit_timespec(), so 0 and -1
 * can't be used as valid date values. The function supports values < -1 though.
 **/
struct timespec time_t_to_full_timespec(time_t t)
{
        if (null_time(t)) {
                return (struct timespec){.tv_nsec = SAMBA_UTIME_OMIT};
        }
        return (struct timespec){.tv_sec = t};
}