source/lib/time.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    time handling functions
   5    Copyright (C) Andrew Tridgell 1992-1997
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 #include "includes.h"
  23
  24 /*
  25   This stuff was largely rewritten by Paul Eggert <eggert@twinsun.com>
  26   in May 1996
  27   */
  28
  29
  30 int serverzone=0;
  31 int extra_time_offset = 0;
  32
  33 extern int DEBUGLEVEL;
  34
  35 #ifndef CHAR_BIT
  36 #define CHAR_BIT 8
  37 #endif
  38
  39 #ifndef TIME_T_MIN
  40 #define TIME_T_MIN ((time_t)0 < (time_t) -1 ? (time_t) 0 \
  41                     : ~ (time_t) 0 << (sizeof (time_t) * CHAR_BIT - 1))
  42 #endif
  43 #ifndef TIME_T_MAX
  44 #define TIME_T_MAX (~ (time_t) 0 - TIME_T_MIN)
  45 #endif
  46
  47
  48
  49 /*******************************************************************
  50 a gettimeofday wrapper
  51 ********************************************************************/
  52 void GetTimeOfDay(struct timeval *tval)
  53 {
  54 #ifdef GETTIMEOFDAY1
  55   gettimeofday(tval);
  56 #else
  57   gettimeofday(tval,NULL);
  58 #endif
  59 }
  60
  61 #define TM_YEAR_BASE 1900
  62
  63 /*******************************************************************
  64 yield the difference between *A and *B, in seconds, ignoring leap seconds
  65 ********************************************************************/
  66 static int tm_diff(struct tm *a, struct tm *b)
  67 {
  68   int ay = a->tm_year + (TM_YEAR_BASE - 1);
  69   int by = b->tm_year + (TM_YEAR_BASE - 1);
  70   int intervening_leap_days =
  71     (ay/4 - by/4) - (ay/100 - by/100) + (ay/400 - by/400);
  72   int years = ay - by;
  73   int days = 365*years + intervening_leap_days + (a->tm_yday - b->tm_yday);
  74   int hours = 24*days + (a->tm_hour - b->tm_hour);
  75   int minutes = 60*hours + (a->tm_min - b->tm_min);
  76   int seconds = 60*minutes + (a->tm_sec - b->tm_sec);
  77   return seconds;
  78 }
  79
  80 /*******************************************************************
  81   return the UTC offset in seconds west of UTC
  82   ******************************************************************/
  83 static int TimeZone(time_t t)
  84 {
  85   struct tm tm_utc = *(gmtime(&t));
  86   return tm_diff(&tm_utc,localtime(&t));
  87 }
  88
  89
  90 /*******************************************************************
  91 init the time differences
  92 ********************************************************************/
  93 void TimeInit(void)
  94 {
  95   serverzone = TimeZone(time(NULL));
  96   DEBUG(4,("Serverzone is %d\n",serverzone));
  97 }
  98
  99
 100 /*******************************************************************
 101 return the same value as TimeZone, but it should be more efficient.
 102
 103 We keep a table of DST offsets to prevent calling localtime() on each
 104 call of this function. This saves a LOT of time on many unixes.
 105
 106 Updated by Paul Eggert <eggert@twinsun.com>
 107 ********************************************************************/
 108 static int TimeZoneFaster(time_t t)
 109 {
 110   static struct dst_table {time_t start,end; int zone;} *dst_table = NULL;
 111   static int table_size = 0;
 112   int i;
 113   int zone = 0;
 114
 115   if (t == 0) t = time(NULL);
 116
 117   /* Tunis has a 8 day DST region, we need to be careful ... */
 118 #define MAX_DST_WIDTH (365*24*60*60)
 119 #define MAX_DST_SKIP (7*24*60*60)
 120
 121   for (i=0;i<table_size;i++)
 122     if (t >= dst_table[i].start && t <= dst_table[i].end) break;
 123
 124   if (i<table_size) {
 125     zone = dst_table[i].zone;
 126   } else {
 127     time_t low,high;
 128
 129     zone = TimeZone(t);
 130     dst_table = (struct dst_table *)Realloc(dst_table,
 131                                               sizeof(dst_table[0])*(i+1));
 132     if (!dst_table) {
 133       table_size = 0;
 134     } else {
 135       table_size++;
 136
 137       dst_table[i].zone = zone;
 138       dst_table[i].start = dst_table[i].end = t;
 139
 140       /* no entry will cover more than 6 months */
 141       low = t - MAX_DST_WIDTH/2;
 142       if (t < low)
 143         low = TIME_T_MIN;
 144
 145       high = t + MAX_DST_WIDTH/2;
 146       if (high < t)
 147         high = TIME_T_MAX;
 148
 149       /* widen the new entry using two bisection searches */
 150       while (low+60*60 < dst_table[i].start) {
 151         if (dst_table[i].start - low > MAX_DST_SKIP*2)
 152           t = dst_table[i].start - MAX_DST_SKIP;
 153         else
 154           t = low + (dst_table[i].start-low)/2;
 155         if (TimeZone(t) == zone)
 156           dst_table[i].start = t;
 157         else
 158           low = t;
 159       }
 160
 161       while (high-60*60 > dst_table[i].end) {
 162         if (high - dst_table[i].end > MAX_DST_SKIP*2)
 163           t = dst_table[i].end + MAX_DST_SKIP;
 164         else
 165           t = high - (high-dst_table[i].end)/2;
 166         if (TimeZone(t) == zone)
 167           dst_table[i].end = t;
 168         else
 169           high = t;
 170       }
 171 #if 0
 172       DEBUG(1,("Added DST entry from %s ",
 173                asctime(localtime(&dst_table[i].start))));
 174       DEBUG(1,("to %s (%d)\n",asctime(localtime(&dst_table[i].end)),
 175                dst_table[i].zone));
 176 #endif
 177     }
 178   }
 179   return zone;
 180 }
 181
 182 /****************************************************************************
 183   return the UTC offset in seconds west of UTC, adjusted for extra time offset
 184   **************************************************************************/
 185 int TimeDiff(time_t t)
 186 {
 187   return TimeZoneFaster(t) + 60*extra_time_offset;
 188 }
 189
 190
 191 /****************************************************************************
 192   return the UTC offset in seconds west of UTC, adjusted for extra time
 193   offset, for a local time value.  If ut = lt + LocTimeDiff(lt), then
 194   lt = ut - TimeDiff(ut), but the converse does not necessarily hold near
 195   daylight savings transitions because some local times are ambiguous.
 196   LocTimeDiff(t) equals TimeDiff(t) except near daylight savings transitions.
 197   +**************************************************************************/
 198 static int LocTimeDiff(time_t lte)
 199 {
 200   time_t lt = lte - 60*extra_time_offset;
 201   int d = TimeZoneFaster(lt);
 202   time_t t = lt + d;
 203
 204   /* if overflow occurred, ignore all the adjustments so far */
 205   if (((lte < lt) ^ (extra_time_offset < 0))  |  ((t < lt) ^ (d < 0)))
 206     t = lte;
 207
 208   /* now t should be close enough to the true UTC to yield the right answer */
 209   return TimeDiff(t);
 210 }
 211
 212
 213 /****************************************************************************
 214 try to optimise the localtime call, it can be quite expenive on some machines
 215 ****************************************************************************/
 216 struct tm *LocalTime(time_t *t)
 217 {
 218   time_t t2 = *t;
 219
 220   t2 -= TimeDiff(t2);
 221
 222   return(gmtime(&t2));
 223 }
 224
 225
 226 #define TIME_FIXUP_CONSTANT (369.0*365.25*24*60*60-(3.0*24*60*60+6.0*60*60))
 227
 228 /****************************************************************************
 229 interpret an 8 byte "filetime" structure to a time_t
 230 It's originally in "100ns units since jan 1st 1601"
 231
 232 It appears to be kludge-GMT (at least for file listings). This means
 233 its the GMT you get by taking a localtime and adding the
 234 serverzone. This is NOT the same as GMT in some cases. This routine
 235 converts this to real GMT.
 236 ****************************************************************************/
 237 time_t interpret_long_date(char *p)
 238 {
 239   double d;
 240   time_t ret;
 241   uint32 tlow,thigh;
 242   tlow = IVAL(p,0);
 243   thigh = IVAL(p,4);
 244
 245   if (thigh == 0) return(0);
 246
 247   d = ((double)thigh)*4.0*(double)(1<<30);
 248   d += (tlow&0xFFF00000);
 249   d *= 1.0e-7;
 250
 251   /* now adjust by 369 years to make the secs since 1970 */
 252   d -= TIME_FIXUP_CONSTANT;
 253
 254   if (!(TIME_T_MIN <= d && d <= TIME_T_MAX))
 255     return(0);
 256
 257   ret = (time_t)(d+0.5);
 258
 259   /* this takes us from kludge-GMT to real GMT */
 260   ret -= serverzone;
 261   ret += LocTimeDiff(ret);
 262
 263   return(ret);
 264 }
 265
 266
 267 /****************************************************************************
 268 put a 8 byte filetime from a time_t
 269 This takes real GMT as input and converts to kludge-GMT
 270 ****************************************************************************/
 271 void put_long_date(char *p,time_t t)
 272 {
 273   uint32 tlow,thigh;
 274   double d;
 275
 276   if (t==0) {
 277     SIVAL(p,0,0); SIVAL(p,4,0);
 278     return;
 279   }
 280
 281   /* this converts GMT to kludge-GMT */
 282   t -= TimeDiff(t) - serverzone;
 283
 284   d = (double) (t);
 285
 286   d += TIME_FIXUP_CONSTANT;
 287
 288   d *= 1.0e7;
 289
 290   thigh = (uint32)(d * (1.0/(4.0*(double)(1<<30))));
 291   tlow = (uint32)(d - ((double)thigh)*4.0*(double)(1<<30));
 292
 293   SIVAL(p,0,tlow);
 294   SIVAL(p,4,thigh);
 295 }
 296
 297
 298 /****************************************************************************
 299 check if it's a null mtime
 300 ****************************************************************************/
 301 BOOL null_mtime(time_t mtime)
 302 {
 303   if (mtime == 0 || mtime == 0xFFFFFFFF || mtime == (time_t)-1)
 304     return(True);
 305   return(False);
 306 }
 307
 308 /*******************************************************************
 309   create a 16 bit dos packed date
 310 ********************************************************************/
 311 static uint16 make_dos_date1(time_t unixdate,struct tm *t)
 312 {
 313   uint16 ret=0;
 314   ret = (((unsigned)(t->tm_mon+1)) >> 3) | ((t->tm_year-80) << 1);
 315   ret = ((ret&0xFF)<<8) | (t->tm_mday | (((t->tm_mon+1) & 0x7) << 5));
 316   return(ret);
 317 }
 318
 319 /*******************************************************************
 320   create a 16 bit dos packed time
 321 ********************************************************************/
 322 static uint16 make_dos_time1(time_t unixdate,struct tm *t)
 323 {
 324   uint16 ret=0;
 325   ret = ((((unsigned)t->tm_min >> 3)&0x7) | (((unsigned)t->tm_hour) << 3));
 326   ret = ((ret&0xFF)<<8) | ((t->tm_sec/2) | ((t->tm_min & 0x7) << 5));
 327   return(ret);
 328 }
 329
 330 /*******************************************************************
 331   create a 32 bit dos packed date/time from some parameters
 332   This takes a GMT time and returns a packed localtime structure
 333 ********************************************************************/
 334 static uint32 make_dos_date(time_t unixdate)
 335 {
 336   struct tm *t;
 337   uint32 ret=0;
 338
 339   t = LocalTime(&unixdate);
 340
 341   ret = make_dos_date1(unixdate,t);
 342   ret = ((ret&0xFFFF)<<16) | make_dos_time1(unixdate,t);
 343
 344   return(ret);
 345 }
 346
 347 /*******************************************************************
 348 put a dos date into a buffer (time/date format)
 349 This takes GMT time and puts local time in the buffer
 350 ********************************************************************/
 351 void put_dos_date(char *buf,int offset,time_t unixdate)
 352 {
 353   uint32 x = make_dos_date(unixdate);
 354   SIVAL(buf,offset,x);
 355 }
 356
 357 /*******************************************************************
 358 put a dos date into a buffer (date/time format)
 359 This takes GMT time and puts local time in the buffer
 360 ********************************************************************/
 361 void put_dos_date2(char *buf,int offset,time_t unixdate)
 362 {
 363   uint32 x = make_dos_date(unixdate);
 364   x = ((x&0xFFFF)<<16) | ((x&0xFFFF0000)>>16);
 365   SIVAL(buf,offset,x);
 366 }
 367
 368 /*******************************************************************
 369 put a dos 32 bit "unix like" date into a buffer. This routine takes
 370 GMT and converts it to LOCAL time before putting it (most SMBs assume
 371 localtime for this sort of date)
 372 ********************************************************************/
 373 void put_dos_date3(char *buf,int offset,time_t unixdate)
 374 {
 375   if (!null_mtime(unixdate))
 376     unixdate -= TimeDiff(unixdate);
 377   SIVAL(buf,offset,unixdate);
 378 }
 379
 380 /*******************************************************************
 381   interpret a 32 bit dos packed date/time to some parameters
 382 ********************************************************************/
 383 static void interpret_dos_date(uint32 date,int *year,int *month,int *day,int *hour,int *minute,int *second)
 384 {
 385   uint32 p0,p1,p2,p3;
 386
 387   p0=date&0xFF; p1=((date&0xFF00)>>8)&0xFF;
 388   p2=((date&0xFF0000)>>16)&0xFF; p3=((date&0xFF000000)>>24)&0xFF;
 389
 390   *second = 2*(p0 & 0x1F);
 391   *minute = ((p0>>5)&0xFF) + ((p1&0x7)<<3);
 392   *hour = (p1>>3)&0xFF;
 393   *day = (p2&0x1F);
 394   *month = ((p2>>5)&0xFF) + ((p3&0x1)<<3) - 1;
 395   *year = ((p3>>1)&0xFF) + 80;
 396 }
 397
 398 /*******************************************************************
 399   create a unix date (int GMT) from a dos date (which is actually in
 400   localtime)
 401 ********************************************************************/
 402 time_t make_unix_date(void *date_ptr)
 403 {
 404   uint32 dos_date=0;
 405   struct tm t;
 406   time_t ret;
 407
 408   dos_date = IVAL(date_ptr,0);
 409
 410   if (dos_date == 0) return(0);
 411
 412   interpret_dos_date(dos_date,&t.tm_year,&t.tm_mon,
 413                      &t.tm_mday,&t.tm_hour,&t.tm_min,&t.tm_sec);
 414   t.tm_isdst = -1;
 415
 416   /* mktime() also does the local to GMT time conversion for us */
 417   ret = mktime(&t);
 418
 419   return(ret);
 420 }
 421
 422 /*******************************************************************
 423 like make_unix_date() but the words are reversed
 424 ********************************************************************/
 425 time_t make_unix_date2(void *date_ptr)
 426 {
 427   uint32 x,x2;
 428
 429   x = IVAL(date_ptr,0);
 430   x2 = ((x&0xFFFF)<<16) | ((x&0xFFFF0000)>>16);
 431   SIVAL(&x,0,x2);
 432
 433   return(make_unix_date((void *)&x));
 434 }
 435
 436 /*******************************************************************
 437   create a unix GMT date from a dos date in 32 bit "unix like" format
 438   these generally arrive as localtimes, with corresponding DST
 439   ******************************************************************/
 440 time_t make_unix_date3(void *date_ptr)
 441 {
 442   time_t t = IVAL(date_ptr,0);
 443   if (!null_mtime(t))
 444     t += LocTimeDiff(t);
 445   return(t);
 446 }
 447
 448 /****************************************************************************
 449   return the date and time as a string
 450 ****************************************************************************/
 451 char *timestring(void )
 452 {
 453   static fstring TimeBuf;
 454   time_t t = time(NULL);
 455   struct tm *tm = LocalTime(&t);
 456
 457 #ifdef NO_STRFTIME
 458   fstrcpy(TimeBuf, asctime(tm));
 459 #elif defined(CLIX) || defined(CONVEX)
 460   strftime(TimeBuf,100,"%m/%d/%Y %I:%M:%S %p",tm);
 461 #elif defined(AMPM)
 462   strftime(TimeBuf,100,"%m/%d/%Y %r",tm);
 463 #elif defined(TZ_TIME)
 464   {
 465     int zone = TimeDiff(t);
 466     int absZoneMinutes = (zone<0 ? -zone : zone) / 60;
 467     size_t len = strftime(TimeBuf,sizeof(TimeBuf)-6,"%m/%d/%Y %T",tm);
 468     sprintf(TimeBuf+len," %c%02d%02d",
 469             zone<0?'+':'-',absZoneMinutes/60,absZoneMinutes%60);
 470   }
 471 #else
 472   strftime(TimeBuf,100,"%m/%d/%Y %T",tm);
 473 #endif
 474   return(TimeBuf);
 475 }
 476