summaryrefslogtreecommitdiffstats
path: root/unix/tclUnixTime.c
blob: e56d60cf5572c13a56fac986e7a60c542fd3471b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
/*
 * tclUnixTime.c --
 *
 *	Contains Unix specific versions of Tcl functions that obtain time
 *	values from the operating system.
 *
 * Copyright (c) 1995 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution of
 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tclUnixTime.c,v 1.37 2010/02/25 22:20:10 nijtmans Exp $
 */

#include "tclInt.h"
#include <locale.h>
#if defined(TCL_WIDE_CLICKS) && defined(MAC_OSX_TCL)
#include <mach/mach_time.h>
#endif

#define TM_YEAR_BASE 1900
#define IsLeapYear(x)	(((x)%4 == 0) && ((x)%100 != 0 || (x)%400 == 0))

/*
 * TclpGetDate is coded to return a pointer to a 'struct tm'. For thread
 * safety, this structure must be in thread-specific data. The 'tmKey'
 * variable is the key to this buffer.
 */

static Tcl_ThreadDataKey tmKey;
typedef struct ThreadSpecificData {
    struct tm gmtime_buf;
    struct tm localtime_buf;
} ThreadSpecificData;

/*
 * If we fall back on the thread-unsafe versions of gmtime and localtime, use
 * this mutex to try to protect them.
 */

TCL_DECLARE_MUTEX(tmMutex)

static char *lastTZ = NULL;	/* Holds the last setting of the TZ
				 * environment variable, or an empty string if
				 * the variable was not set. */

/*
 * Static functions declared in this file.
 */

static void		SetTZIfNecessary(void);
static void		CleanupMemory(ClientData clientData);
static void		NativeScaleTime(Tcl_Time *timebuf,
			    ClientData clientData);
static void		NativeGetTime(Tcl_Time *timebuf,
			    ClientData clientData);

/*
 * TIP #233 (Virtualized Time): Data for the time hooks, if any.
 */

Tcl_GetTimeProc *tclGetTimeProcPtr = NativeGetTime;
Tcl_ScaleTimeProc *tclScaleTimeProcPtr = NativeScaleTime;
ClientData tclTimeClientData = NULL;

/*
 *-----------------------------------------------------------------------------
 *
 * TclpGetSeconds --
 *
 *	This procedure returns the number of seconds from the epoch. On most
 *	Unix systems the epoch is Midnight Jan 1, 1970 GMT.
 *
 * Results:
 *	Number of seconds from the epoch.
 *
 * Side effects:
 *	None.
 *
 *-----------------------------------------------------------------------------
 */

unsigned long
TclpGetSeconds(void)
{
    return time(NULL);
}

/*
 *-----------------------------------------------------------------------------
 *
 * TclpGetClicks --
 *
 *	This procedure returns a value that represents the highest resolution
 *	clock available on the system. There are no garantees on what the
 *	resolution will be. In Tcl we will call this value a "click". The
 *	start time is also system dependant.
 *
 * Results:
 *	Number of clicks from some start time.
 *
 * Side effects:
 *	None.
 *
 *-----------------------------------------------------------------------------
 */

unsigned long
TclpGetClicks(void)
{
    unsigned long now;

#ifdef NO_GETTOD
    if (tclGetTimeProcPtr != NativeGetTime) {
	Tcl_Time time;

	tclGetTimeProcPtr(&time, tclTimeClientData);
	now = time.sec*1000000 + time.usec;
    } else {
	/*
	 * A semi-NativeGetTime, specialized to clicks.
	 */
	struct tms dummy;

	now = (unsigned long) times(&dummy);
    }
#else
    Tcl_Time time;

    tclGetTimeProcPtr(&time, tclTimeClientData);
    now = time.sec*1000000 + time.usec;
#endif

    return now;
}
#ifdef TCL_WIDE_CLICKS

/*
 *-----------------------------------------------------------------------------
 *
 * TclpGetWideClicks --
 *
 *	This procedure returns a WideInt value that represents the highest
 *	resolution clock available on the system. There are no garantees on
 *	what the resolution will be. In Tcl we will call this value a "click".
 *	The start time is also system dependant.
 *
 * Results:
 *	Number of WideInt clicks from some start time.
 *
 * Side effects:
 *	None.
 *
 *-----------------------------------------------------------------------------
 */

Tcl_WideInt
TclpGetWideClicks(void)
{
    Tcl_WideInt now;

    if (tclGetTimeProcPtr != NativeGetTime) {
	Tcl_Time time;

	tclGetTimeProcPtr(&time, tclTimeClientData);
	now = (Tcl_WideInt) (time.sec*1000000 + time.usec);
    } else {
#ifdef MAC_OSX_TCL
	now = (Tcl_WideInt) (mach_absolute_time() & INT64_MAX);
#else
#error Wide high-resolution clicks not implemented on this platform
#endif
    }

    return now;
}

/*
 *-----------------------------------------------------------------------------
 *
 * TclpWideClicksToNanoseconds --
 *
 *	This procedure converts click values from the TclpGetWideClicks native
 *	resolution to nanosecond resolution.
 *
 * Results:
 *	Number of nanoseconds from some start time.
 *
 * Side effects:
 *	None.
 *
 *-----------------------------------------------------------------------------
 */

double
TclpWideClicksToNanoseconds(
    Tcl_WideInt clicks)
{
    double nsec;

    if (tclGetTimeProcPtr != NativeGetTime) {
	nsec = clicks * 1000;
    } else {
#ifdef MAC_OSX_TCL
	static mach_timebase_info_data_t tb;
	static uint64_t maxClicksForUInt64;
	
	if (!tb.denom) {
	    mach_timebase_info(&tb);
	    maxClicksForUInt64 = UINT64_MAX / tb.numer;
	}
	if ((uint64_t) clicks < maxClicksForUInt64) {
	    nsec = ((uint64_t) clicks) * tb.numer / tb.denom;
	} else {
	    nsec = ((long double) (uint64_t) clicks) * tb.numer / tb.denom;
	}
#else
#error Wide high-resolution clicks not implemented on this platform
#endif
    }

    return nsec;
}
#endif /* TCL_WIDE_CLICKS */

/*
 *----------------------------------------------------------------------
 *
 * TclpGetTimeZone --
 *
 *	Determines the current timezone. The method varies wildly between
 *	different platform implementations, so its hidden in this function.
 *
 * Results:
 *	The return value is the local time zone, measured in minutes away from
 *	GMT (-ve for east, +ve for west).
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

int
TclpGetTimeZone(
    unsigned long currentTime)
{
    int timeZone;

    /*
     * We prefer first to use the time zone in "struct tm" if the structure
     * contains such a member. Following that, we try to locate the external
     * 'timezone' variable and use its value. If both of those methods fail,
     * we attempt to convert a known time to local time and use the difference
     * from UTC as the local time zone. In all cases, we need to undo any
     * Daylight Saving Time adjustment.
     */

#if defined(HAVE_TM_TZADJ)
#define TCL_GOT_TIMEZONE
    /*
     * Struct tm contains tm_tzadj - that value may be used.
     */

    time_t curTime = (time_t) currentTime;
    struct tm *timeDataPtr = TclpLocaltime(&curTime);

    timeZone = timeDataPtr->tm_tzadj / 60;
    if (timeDataPtr->tm_isdst) {
	timeZone += 60;
    }
#endif

#if defined(HAVE_TM_GMTOFF) && !defined (TCL_GOT_TIMEZONE)
#define TCL_GOT_TIMEZONE
    /*
     * Struct tm contains tm_gmtoff - that value may be used.
     */

    time_t curTime = (time_t) currentTime;
    struct tm *timeDataPtr = TclpLocaltime(&curTime);

    timeZone = -(timeDataPtr->tm_gmtoff / 60);
    if (timeDataPtr->tm_isdst) {
	timeZone += 60;
    }
#endif

#if defined(HAVE_TIMEZONE_VAR) && !defined(TCL_GOT_TIMEZONE) && !defined(USE_DELTA_FOR_TZ)
#define TCL_GOT_TIMEZONE
    /*
     * The 'timezone' external var is present and may be used.
     */

    SetTZIfNecessary();

    /*
     * Note: this is not a typo in "timezone" below! See tzset documentation
     * for details.
     */

    timeZone = timezone / 60;
#endif

#if !defined(TCL_GOT_TIMEZONE)
#define TCL_GOT_TIMEZONE
    /*
     * Fallback - determine time zone with a known reference time.
     */

    time_t tt;
    struct tm *stm;

    tt = 849268800L;		/* 1996-11-29 12:00:00  GMT */
    stm = TclpLocaltime(&tt);	/* eg 1996-11-29  6:00:00  CST6CDT */

    /*
     * The calculation below assumes a max of +12 or -12 hours from GMT.
     */

    timeZone = (12 - stm->tm_hour)*60 + (0 - stm->tm_min);
    if (stm->tm_isdst) {
	timeZone += 60;
    }

    /*
     * Now have offset for our known reference time, eg +360 for CST6CDT.
     */
#endif

#ifndef TCL_GOT_TIMEZONE
    /*
     * Cause fatal compile error, we don't know how to get timezone.
     */

#error autoconf did not figure out how to determine the timezone.
#endif

    return timeZone;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetTime --
 *
 *	Gets the current system time in seconds and microseconds since the
 *	beginning of the epoch: 00:00 UCT, January 1, 1970.
 *
 *	This function is hooked, allowing users to specify their own virtual
 *	system time.
 *
 * Results:
 *	Returns the current time in timePtr.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_GetTime(
    Tcl_Time *timePtr)		/* Location to store time information. */
{
    tclGetTimeProcPtr(timePtr, tclTimeClientData);
}

/*
 *----------------------------------------------------------------------
 *
 * TclpGetDate --
 *
 *	This function converts between seconds and struct tm. If useGMT is
 *	true, then the returned date will be in Greenwich Mean Time (GMT).
 *	Otherwise, it will be in the local time zone.
 *
 * Results:
 *	Returns a static tm structure.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

struct tm *
TclpGetDate(
    const time_t *time,
    int useGMT)
{
    if (useGMT) {
	return TclpGmtime(time);
    } else {
	return TclpLocaltime(time);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TclpGmtime --
 *
 *	Wrapper around the 'gmtime' library function to make it thread safe.
 *
 * Results:
 *	Returns a pointer to a 'struct tm' in thread-specific data.
 *
 * Side effects:
 *	Invokes gmtime or gmtime_r as appropriate.
 *
 *----------------------------------------------------------------------
 */

struct tm *
TclpGmtime(
    const time_t *timePtr)	/* Pointer to the number of seconds since the
				 * local system's epoch */
{
    /*
     * Get a thread-local buffer to hold the returned time.
     */

    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&tmKey);

#ifdef HAVE_GMTIME_R
    gmtime_r(timePtr, &(tsdPtr->gmtime_buf));
#else
    Tcl_MutexLock(&tmMutex);
    memcpy(&(tsdPtr->gmtime_buf), gmtime(timePtr), sizeof(struct tm));
    Tcl_MutexUnlock(&tmMutex);
#endif

    return &(tsdPtr->gmtime_buf);
}

/*
 * Forwarder for obsolete item in Stubs
 */

struct tm *
TclpGmtime_unix(
    const time_t *timePtr)
{
    return TclpGmtime(timePtr);
}

/*
 *----------------------------------------------------------------------
 *
 * TclpLocaltime --
 *
 *	Wrapper around the 'localtime' library function to make it thread
 *	safe.
 *
 * Results:
 *	Returns a pointer to a 'struct tm' in thread-specific data.
 *
 * Side effects:
 *	Invokes localtime or localtime_r as appropriate.
 *
 *----------------------------------------------------------------------
 */

struct tm *
TclpLocaltime(
    const time_t *timePtr)	/* Pointer to the number of seconds since the
				 * local system's epoch */
{
    /*
     * Get a thread-local buffer to hold the returned time.
     */

    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&tmKey);

    SetTZIfNecessary();
#ifdef HAVE_LOCALTIME_R
    localtime_r(timePtr, &(tsdPtr->localtime_buf));
#else
    Tcl_MutexLock(&tmMutex);
    memcpy(&(tsdPtr->localtime_buf), localtime(timePtr), sizeof(struct tm));
    Tcl_MutexUnlock(&tmMutex);
#endif

    return &(tsdPtr->localtime_buf);
}
/*
 * Forwarder for obsolete item in Stubs
 */
struct tm*
TclpLocaltime_unix(
    const time_t *timePtr)
{
    return TclpLocaltime(timePtr);
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_SetTimeProc --
 *
 *	TIP #233 (Virtualized Time): Registers two handlers for the
 *	virtualization of Tcl's access to time information.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Remembers the handlers, alters core behaviour.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_SetTimeProc(
    Tcl_GetTimeProc *getProc,
    Tcl_ScaleTimeProc *scaleProc,
    ClientData clientData)
{
    tclGetTimeProcPtr = getProc;
    tclScaleTimeProcPtr = scaleProc;
    tclTimeClientData = clientData;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_QueryTimeProc --
 *
 *	TIP #233 (Virtualized Time): Query which time handlers are registered.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_QueryTimeProc(
    Tcl_GetTimeProc **getProc,
    Tcl_ScaleTimeProc **scaleProc,
    ClientData *clientData)
{
    if (getProc) {
	*getProc = tclGetTimeProcPtr;
    }
    if (scaleProc) {
	*scaleProc = tclScaleTimeProcPtr;
    }
    if (clientData) {
	*clientData = tclTimeClientData;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * NativeScaleTime --
 *
 *	TIP #233: Scale from virtual time to the real-time. For native scaling
 *	the relationship is 1:1 and nothing has to be done.
 *
 * Results:
 *	Scales the time in timePtr.
 *
 * Side effects:
 *	See above.
 *
 *----------------------------------------------------------------------
 */

static void
NativeScaleTime(
    Tcl_Time *timePtr,
    ClientData clientData)
{
    /* Native scale is 1:1. Nothing is done */
}

/*
 *----------------------------------------------------------------------
 *
 * NativeGetTime --
 *
 *	TIP #233: Gets the current system time in seconds and microseconds
 *	since the beginning of the epoch: 00:00 UCT, January 1, 1970.
 *
 * Results:
 *	Returns the current time in timePtr.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static void
NativeGetTime(
    Tcl_Time *timePtr,
    ClientData clientData)
{
    struct timeval tv;

    (void) gettimeofday(&tv, NULL);
    timePtr->sec = tv.tv_sec;
    timePtr->usec = tv.tv_usec;
}
/*
 *----------------------------------------------------------------------
 *
 * SetTZIfNecessary --
 *
 *	Determines whether a call to 'tzset' is needed prior to the next call
 *	to 'localtime' or examination of the 'timezone' variable.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	If 'tzset' has never been called in the current process, or if the
 *	value of the environment variable TZ has changed since the last call
 *	to 'tzset', then 'tzset' is called again.
 *
 *----------------------------------------------------------------------
 */

static void
SetTZIfNecessary(void)
{
    const char *newTZ = getenv("TZ");

    Tcl_MutexLock(&tmMutex);
    if (newTZ == NULL) {
	newTZ = "";
    }
    if (lastTZ == NULL || strcmp(lastTZ, newTZ)) {
	tzset();
	if (lastTZ == NULL) {
	    Tcl_CreateExitHandler(CleanupMemory, NULL);
	} else {
	    Tcl_Free(lastTZ);
	}
	lastTZ = ckalloc(strlen(newTZ) + 1);
	strcpy(lastTZ, newTZ);
    }
    Tcl_MutexUnlock(&tmMutex);
}

/*
 *----------------------------------------------------------------------
 *
 * CleanupMemory --
 *
 *	Releases the private copy of the TZ environment variable upon exit
 *	from Tcl.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Frees allocated memory.
 *
 *----------------------------------------------------------------------
 */

static void
CleanupMemory(
    ClientData ignored)
{
    ckfree(lastTZ);
}

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */