vfs/samba/lib/time.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    time handling functions
   5    Copyright (C) Andrew Tridgell 1992-1998
   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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 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 HAVE_GETTIMEOFDAY_TZ
  55         gettimeofday(tval,NULL);
  56 #else
  57         gettimeofday(tval);
  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
  78   return seconds;
  79 }
  80
  81 /*******************************************************************
  82   return the UTC offset in seconds west of UTC, or 0 if it cannot be determined
  83   ******************************************************************/
  84 static int TimeZone(time_t t)
  85 {
  86   struct tm *tm = gmtime(&t);
  87   struct tm tm_utc;
  88   if (!tm)
  89     return 0;
  90   tm_utc = *tm;
  91   tm = localtime(&t);
  92   if (!tm)
  93     return 0;
  94   return tm_diff(&tm_utc,tm);
  95
  96 }
  97
  98
  99 /*******************************************************************
 100 init the time differences
 101 ********************************************************************/
 102 void TimeInit(void)
 103 {
 104   serverzone = TimeZone(time(NULL));
 105
 106   if ((serverzone % 60) != 0) {
 107           DEBUG(1,("WARNING: Your timezone is not a multiple of 1 minute.\n"));
 108   }
 109
 110   DEBUG(4,("Serverzone is %d\n",serverzone));
 111 }
 112
 113
 114 /*******************************************************************
 115 return the same value as TimeZone, but it should be more efficient.
 116
 117 We keep a table of DST offsets to prevent calling localtime() on each
 118 call of this function. This saves a LOT of time on many unixes.
 119
 120 Updated by Paul Eggert <eggert@twinsun.com>
 121 ********************************************************************/
 122 static int TimeZoneFaster(time_t t)
 123 {
 124   static struct dst_table {time_t start,end; int zone;} *dst_table = NULL;
 125   static int table_size = 0;
 126   int i;
 127   int zone = 0;
 128
 129   if (t == 0) t = time(NULL);
 130
 131   /* Tunis has a 8 day DST region, we need to be careful ... */
 132 #define MAX_DST_WIDTH (365*24*60*60)
 133 #define MAX_DST_SKIP (7*24*60*60)
 134
 135   for (i=0;i<table_size;i++)
 136     if (t >= dst_table[i].start && t <= dst_table[i].end) break;
 137
 138   if (i<table_size) {
 139     zone = dst_table[i].zone;
 140   } else {
 141     time_t low,high;
 142
 143     zone = TimeZone(t);
 144     dst_table = (struct dst_table *)Realloc(dst_table,
 145                                               sizeof(dst_table[0])*(i+1));
 146     if (!dst_table) {
 147       table_size = 0;
 148     } else {
 149       table_size++;
 150
 151       dst_table[i].zone = zone;
 152       dst_table[i].start = dst_table[i].end = t;
 153
 154       /* no entry will cover more than 6 months */
 155       low = t - MAX_DST_WIDTH/2;
 156       if (t < low)
 157         low = TIME_T_MIN;
 158
 159       high = t + MAX_DST_WIDTH/2;
 160       if (high < t)
 161         high = TIME_T_MAX;
 162
 163       /* widen the new entry using two bisection searches */
 164       while (low+60*60 < dst_table[i].start) {
 165         if (dst_table[i].start - low > MAX_DST_SKIP*2)
 166           t = dst_table[i].start - MAX_DST_SKIP;
 167         else
 168           t = low + (dst_table[i].start-low)/2;
 169         if (TimeZone(t) == zone)
 170           dst_table[i].start = t;
 171         else
 172           low = t;
 173       }
 174
 175       while (high-60*60 > dst_table[i].end) {
 176         if (high - dst_table[i].end > MAX_DST_SKIP*2)
 177           t = dst_table[i].end + MAX_DST_SKIP;
 178         else
 179           t = high - (high-dst_table[i].end)/2;
 180         if (TimeZone(t) == zone)
 181           dst_table[i].end = t;
 182         else
 183           high = t;
 184       }
 185 #if 0
 186       DEBUG(1,("Added DST entry from %s ",
 187                asctime(localtime(&dst_table[i].start))));
 188       DEBUG(1,("to %s (%d)\n",asctime(localtime(&dst_table[i].end)),
 189                dst_table[i].zone));
 190 #endif
 191     }
 192   }
 193   return zone;
 194 }
 195
 196 /****************************************************************************
 197   return the UTC offset in seconds west of UTC, adjusted for extra time offset
 198   **************************************************************************/
 199 int TimeDiff(time_t t)
 200 {
 201   return TimeZoneFaster(t) + 60*extra_time_offset;
 202 }
 203
 204
 205 /****************************************************************************
 206   return the UTC offset in seconds west of UTC, adjusted for extra time
 207   offset, for a local time value.  If ut = lt + LocTimeDiff(lt), then
 208   lt = ut - TimeDiff(ut), but the converse does not necessarily hold near
 209   daylight savings transitions because some local times are ambiguous.
 210   LocTimeDiff(t) equals TimeDiff(t) except near daylight savings transitions.
 211   +**************************************************************************/
 212 static int LocTimeDiff(time_t lte)
 213 {
 214   time_t lt = lte - 60*extra_time_offset;
 215   int d = TimeZoneFaster(lt);
 216   time_t t = lt + d;
 217
 218   /* if overflow occurred, ignore all the adjustments so far */
 219   if (((lte < lt) ^ (extra_time_offset < 0))  |  ((t < lt) ^ (d < 0)))
 220     t = lte;
 221
 222   /* now t should be close enough to the true UTC to yield the right answer */
 223   return TimeDiff(t);
 224 }
 225
 226
 227 /****************************************************************************
 228 try to optimise the localtime call, it can be quite expensive on some machines
 229 ****************************************************************************/
 230 struct tm *LocalTime(time_t *t)
 231 {
 232   time_t t2 = *t;
 233
 234   t2 -= TimeDiff(t2);
 235
 236   return(gmtime(&t2));
 237 }
 238
 239 #define TIME_FIXUP_CONSTANT (369.0*365.25*24*60*60-(3.0*24*60*60+6.0*60*60))
 240
 241 /****************************************************************************
 242 interpret an 8 byte "filetime" structure to a time_t
 243 It's originally in "100ns units since jan 1st 1601"
 244
 245 It appears to be kludge-GMT (at least for file listings). This means
 246 its the GMT you get by taking a localtime and adding the
 247 serverzone. This is NOT the same as GMT in some cases. This routine
 248 converts this to real GMT.
 249 ****************************************************************************/
 250 time_t nt_time_to_unix(NTTIME *nt)
 251 {
 252   double d;
 253   time_t ret;
 254   /* The next two lines are a fix needed for the
 255      broken SCO compiler. JRA. */
 256   time_t l_time_min = TIME_T_MIN;
 257   time_t l_time_max = TIME_T_MAX;
 258
 259   if (nt->high == 0) return(0);
 260
 261   d = ((double)nt->high)*4.0*(double)(1<<30);
 262   d += (nt->low&0xFFF00000);
 263   d *= 1.0e-7;
 264
 265   /* now adjust by 369 years to make the secs since 1970 */
 266   d -= TIME_FIXUP_CONSTANT;
 267
 268   if (!(l_time_min <= d && d <= l_time_max))
 269     return(0);
 270
 271   ret = (time_t)(d+0.5);
 272
 273   /* this takes us from kludge-GMT to real GMT */
 274   ret -= serverzone;
 275   ret += LocTimeDiff(ret);
 276
 277   return(ret);
 278 }
 279
 280
 281
 282 /****************************************************************************
 283 interprets an nt time into a unix time_t
 284 ****************************************************************************/
 285 time_t interpret_long_date(char *p)
 286 {
 287         NTTIME nt;
 288         nt.low = IVAL(p,0);
 289         nt.high = IVAL(p,4);
 290         return nt_time_to_unix(&nt);
 291 }
 292
 293 /****************************************************************************
 294 put a 8 byte filetime from a time_t
 295 This takes real GMT as input and converts to kludge-GMT
 296 ****************************************************************************/
 297 void unix_to_nt_time(NTTIME *nt, time_t t)
 298 {
 299         double d;
 300
 301         if (t==0)
 302         {
 303                 nt->low = 0;
 304                 nt->high = 0;
 305                 return;
 306         }
 307
 308         /* this converts GMT to kludge-GMT */
 309         t -= LocTimeDiff(t) - serverzone;
 310
 311         d = (double)(t);
 312         d += TIME_FIXUP_CONSTANT;
 313         d *= 1.0e7;
 314
 315         nt->high = (uint32)(d * (1.0/(4.0*(double)(1<<30))));
 316         nt->low  = (uint32)(d - ((double)nt->high)*4.0*(double)(1<<30));
 317 }
 318
 319
 320 /****************************************************************************
 321 take an NTTIME structure, containing high / low time.  convert to unix time.
 322 lkclXXXX this may need 2 SIVALs not a memcpy.  we'll see...
 323 ****************************************************************************/
 324 void put_long_date(char *p,time_t t)
 325 {
 326         NTTIME nt;
 327         unix_to_nt_time(&nt, t);
 328         SIVAL(p, 0, nt.low);
 329         SIVAL(p, 4, nt.high);
 330 }
 331
 332 /****************************************************************************
 333 check if it's a null mtime
 334 ****************************************************************************/
 335 BOOL null_mtime(time_t mtime)
 336 {
 337   if (mtime == (time_t)0 || mtime == (time_t)0xFFFFFFFF || mtime == (time_t)-1)
 338     return(True);
 339   return(False);
 340 }
 341
 342 /*******************************************************************
 343   create a 16 bit dos packed date
 344 ********************************************************************/
 345 static uint16 make_dos_date1(struct tm *t)
 346 {
 347   uint16 ret=0;
 348   ret = (((unsigned)(t->tm_mon+1)) >> 3) | ((t->tm_year-80) << 1);
 349   ret = ((ret&0xFF)<<8) | (t->tm_mday | (((t->tm_mon+1) & 0x7) << 5));
 350   return(ret);
 351 }
 352
 353 /*******************************************************************
 354   create a 16 bit dos packed time
 355 ********************************************************************/
 356 static uint16 make_dos_time1(struct tm *t)
 357 {
 358   uint16 ret=0;
 359   ret = ((((unsigned)t->tm_min >> 3)&0x7) | (((unsigned)t->tm_hour) << 3));
 360   ret = ((ret&0xFF)<<8) | ((t->tm_sec/2) | ((t->tm_min & 0x7) << 5));
 361   return(ret);
 362 }
 363
 364 /*******************************************************************
 365   create a 32 bit dos packed date/time from some parameters
 366   This takes a GMT time and returns a packed localtime structure
 367 ********************************************************************/
 368 static uint32 make_dos_date(time_t unixdate)
 369 {
 370   struct tm *t;
 371   uint32 ret=0;
 372
 373   t = LocalTime(&unixdate);
 374   if (!t)
 375     return 0xFFFFFFFF;
 376
 377   ret = make_dos_date1(t);
 378   ret = ((ret&0xFFFF)<<16) | make_dos_time1(t);
 379
 380   return(ret);
 381 }
 382
 383 /*******************************************************************
 384 put a dos date into a buffer (time/date format)
 385 This takes GMT time and puts local time in the buffer
 386 ********************************************************************/
 387 void put_dos_date(char *buf,int offset,time_t unixdate)
 388 {
 389   uint32 x = make_dos_date(unixdate);
 390   SIVAL(buf,offset,x);
 391 }
 392
 393 /*******************************************************************
 394 put a dos date into a buffer (date/time format)
 395 This takes GMT time and puts local time in the buffer
 396 ********************************************************************/
 397 void put_dos_date2(char *buf,int offset,time_t unixdate)
 398 {
 399   uint32 x = make_dos_date(unixdate);
 400   x = ((x&0xFFFF)<<16) | ((x&0xFFFF0000)>>16);
 401   SIVAL(buf,offset,x);
 402 }
 403
 404 /*******************************************************************
 405 put a dos 32 bit "unix like" date into a buffer. This routine takes
 406 GMT and converts it to LOCAL time before putting it (most SMBs assume
 407 localtime for this sort of date)
 408 ********************************************************************/
 409 void put_dos_date3(char *buf,int offset,time_t unixdate)
 410 {
 411   if (!null_mtime(unixdate))
 412     unixdate -= TimeDiff(unixdate);
 413   SIVAL(buf,offset,unixdate);
 414 }
 415
 416 /*******************************************************************
 417   interpret a 32 bit dos packed date/time to some parameters
 418 ********************************************************************/
 419 static void interpret_dos_date(uint32 date,int *year,int *month,int *day,int *hour,int *minute,int *second)
 420 {
 421   uint32 p0,p1,p2,p3;
 422
 423   p0=date&0xFF; p1=((date&0xFF00)>>8)&0xFF;
 424   p2=((date&0xFF0000)>>16)&0xFF; p3=((date&0xFF000000)>>24)&0xFF;
 425
 426   *second = 2*(p0 & 0x1F);
 427   *minute = ((p0>>5)&0xFF) + ((p1&0x7)<<3);
 428   *hour = (p1>>3)&0xFF;
 429   *day = (p2&0x1F);
 430   *month = ((p2>>5)&0xFF) + ((p3&0x1)<<3) - 1;
 431   *year = ((p3>>1)&0xFF) + 80;
 432 }
 433
 434 /*******************************************************************
 435   create a unix date (int GMT) from a dos date (which is actually in
 436   localtime)
 437 ********************************************************************/
 438 time_t make_unix_date(void *date_ptr)
 439 {
 440   uint32 dos_date=0;
 441   struct tm t;
 442   time_t ret;
 443
 444   dos_date = IVAL(date_ptr,0);
 445
 446   if (dos_date == 0) return(0);
 447
 448   interpret_dos_date(dos_date,&t.tm_year,&t.tm_mon,
 449                      &t.tm_mday,&t.tm_hour,&t.tm_min,&t.tm_sec);
 450   t.tm_isdst = -1;
 451
 452   /* mktime() also does the local to GMT time conversion for us */
 453   ret = mktime(&t);
 454
 455   return(ret);
 456 }
 457
 458 /*******************************************************************
 459 like make_unix_date() but the words are reversed
 460 ********************************************************************/
 461 time_t make_unix_date2(void *date_ptr)
 462 {
 463   uint32 x,x2;
 464
 465   x = IVAL(date_ptr,0);
 466   x2 = ((x&0xFFFF)<<16) | ((x&0xFFFF0000)>>16);
 467   SIVAL(&x,0,x2);
 468
 469   return(make_unix_date((void *)&x));
 470 }
 471
 472 /*******************************************************************
 473   create a unix GMT date from a dos date in 32 bit "unix like" format
 474   these generally arrive as localtimes, with corresponding DST
 475   ******************************************************************/
 476 time_t make_unix_date3(void *date_ptr)
 477 {
 478   time_t t = (time_t)IVAL(date_ptr,0);
 479   if (!null_mtime(t))
 480     t += LocTimeDiff(t);
 481   return(t);
 482 }
 483
 484 #if 0
 485 /***************************************************************************
 486 return a HTTP/1.0 time string
 487   ***************************************************************************/
 488 char *http_timestring(time_t t)
 489 {
 490   static fstring buf;
 491   struct tm *tm = LocalTime(&t);
 492
 493   if (!tm)
 494     slprintf(buf,sizeof(buf)-1,"%ld seconds since the Epoch",(long)t);
 495   else
 496 #ifndef HAVE_STRFTIME
 497   fstrcpy(buf, asctime(tm));
 498 #else /* !HAVE_STRFTIME */
 499   strftime(buf, sizeof(buf)-1, "%a, %d %b %Y %H:%M:%S %Z", tm);
 500 #endif /* !HAVE_STRFTIME */
 501   return buf;
 502 }
 503 #endif /*0 */
 504
 505
 506 /****************************************************************************
 507   return the date and time as a string
 508 ****************************************************************************/
 509 char *timestring(void )
 510 {
 511         static fstring TimeBuf;
 512         time_t t = time(NULL);
 513         struct tm *tm = LocalTime(&t);
 514
 515         if (!tm) {
 516                 slprintf(TimeBuf,sizeof(TimeBuf)-1,"%ld seconds since the Epoch",(long)t);
 517         } else {
 518 #ifdef HAVE_STRFTIME
 519                 strftime(TimeBuf,100,"%Y/%m/%d %H:%M:%S",tm);
 520 #else
 521                 fstrcpy(TimeBuf, asctime(tm));
 522 #endif
 523         }
 524         return(TimeBuf);
 525 }
 526
 527 /****************************************************************************
 528   return the best approximation to a 'create time' under UNIX from a stat
 529   structure.
 530 ****************************************************************************/
 531
 532 time_t get_create_time(SMB_STRUCT_STAT *st,BOOL fake_dirs)
 533 {
 534   time_t ret, ret1;
 535
 536   if(S_ISDIR(st->st_mode) && fake_dirs)
 537     return (time_t)315493200L;          /* 1/1/1980 */
 538
 539   ret = MIN(st->st_ctime, st->st_mtime);
 540   ret1 = MIN(ret, st->st_atime);
 541
 542   if(ret1 != (time_t)0)
 543     return ret1;
 544
 545   /*
 546    * One of ctime, mtime or atime was zero (probably atime).
 547    * Just return MIN(ctime, mtime).
 548    */
 549   return ret;
 550 }
 551