1/*
2 * Copyright (C) 2004-2008  Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 1998-2001, 2003  Internet Software Consortium.
4 *
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 * PERFORMANCE OF THIS SOFTWARE.
16 */
17
18/* $Id: time.c,v 1.56 2008/02/15 23:46:51 tbox Exp $ */
19
20/*! \file */
21
22#include <config.h>
23
24#include <errno.h>
25#include <limits.h>
26#include <syslog.h>
27#include <time.h>
28
29#include <sys/time.h>	/* Required for struct timeval on some platforms. */
30
31#include <isc/log.h>
32#include <isc/print.h>
33#include <isc/strerror.h>
34#include <isc/string.h>
35#include <isc/time.h>
36#include <isc/util.h>
37
38#define NS_PER_S	1000000000	/*%< Nanoseconds per second. */
39#define NS_PER_US	1000		/*%< Nanoseconds per microsecond. */
40#define US_PER_S	1000000		/*%< Microseconds per second. */
41
42/*
43 * All of the INSIST()s checks of nanoseconds < NS_PER_S are for
44 * consistency checking of the type. In lieu of magic numbers, it
45 * is the best we've got.  The check is only performed on functions which
46 * need an initialized type.
47 */
48
49#ifndef ISC_FIX_TV_USEC
50#define ISC_FIX_TV_USEC 1
51#endif
52
53/*%
54 *** Intervals
55 ***/
56
57static isc_interval_t zero_interval = { 0, 0 };
58isc_interval_t *isc_interval_zero = &zero_interval;
59
60#if ISC_FIX_TV_USEC
61static inline void
62fix_tv_usec(struct timeval *tv) {
63	isc_boolean_t fixed = ISC_FALSE;
64
65	if (tv->tv_usec < 0) {
66		fixed = ISC_TRUE;
67		do {
68			tv->tv_sec -= 1;
69			tv->tv_usec += US_PER_S;
70		} while (tv->tv_usec < 0);
71	} else if (tv->tv_usec >= US_PER_S) {
72		fixed = ISC_TRUE;
73		do {
74			tv->tv_sec += 1;
75			tv->tv_usec -= US_PER_S;
76		} while (tv->tv_usec >=US_PER_S);
77	}
78	/*
79	 * Call syslog directly as was are called from the logging functions.
80	 */
81	if (fixed)
82		(void)syslog(LOG_ERR, "gettimeofday returned bad tv_usec: corrected");
83}
84#endif
85
86void
87isc_interval_set(isc_interval_t *i,
88		 unsigned int seconds, unsigned int nanoseconds)
89{
90	REQUIRE(i != NULL);
91	REQUIRE(nanoseconds < NS_PER_S);
92
93	i->seconds = seconds;
94	i->nanoseconds = nanoseconds;
95}
96
97isc_boolean_t
98isc_interval_iszero(const isc_interval_t *i) {
99	REQUIRE(i != NULL);
100	INSIST(i->nanoseconds < NS_PER_S);
101
102	if (i->seconds == 0 && i->nanoseconds == 0)
103		return (ISC_TRUE);
104
105	return (ISC_FALSE);
106}
107
108
109/***
110 *** Absolute Times
111 ***/
112
113static isc_time_t epoch = { 0, 0 };
114isc_time_t *isc_time_epoch = &epoch;
115
116void
117isc_time_set(isc_time_t *t, unsigned int seconds, unsigned int nanoseconds) {
118	REQUIRE(t != NULL);
119	REQUIRE(nanoseconds < NS_PER_S);
120
121	t->seconds = seconds;
122	t->nanoseconds = nanoseconds;
123}
124
125void
126isc_time_settoepoch(isc_time_t *t) {
127	REQUIRE(t != NULL);
128
129	t->seconds = 0;
130	t->nanoseconds = 0;
131}
132
133isc_boolean_t
134isc_time_isepoch(const isc_time_t *t) {
135	REQUIRE(t != NULL);
136	INSIST(t->nanoseconds < NS_PER_S);
137
138	if (t->seconds == 0 && t->nanoseconds == 0)
139		return (ISC_TRUE);
140
141	return (ISC_FALSE);
142}
143
144
145isc_result_t
146isc_time_now(isc_time_t *t) {
147	struct timeval tv;
148	char strbuf[ISC_STRERRORSIZE];
149
150	REQUIRE(t != NULL);
151
152	if (gettimeofday(&tv, NULL) == -1) {
153		isc__strerror(errno, strbuf, sizeof(strbuf));
154		UNEXPECTED_ERROR(__FILE__, __LINE__, "%s", strbuf);
155		return (ISC_R_UNEXPECTED);
156	}
157
158	/*
159	 * Does POSIX guarantee the signedness of tv_sec and tv_usec?  If not,
160	 * then this test will generate warnings for platforms on which it is
161	 * unsigned.  In any event, the chances of any of these problems
162	 * happening are pretty much zero, but since the libisc library ensures
163	 * certain things to be true ...
164	 */
165#if ISC_FIX_TV_USEC
166	fix_tv_usec(&tv);
167	if (tv.tv_sec < 0)
168		return (ISC_R_UNEXPECTED);
169#else
170	if (tv.tv_sec < 0 || tv.tv_usec < 0 || tv.tv_usec >= US_PER_S)
171		return (ISC_R_UNEXPECTED);
172#endif
173
174	/*
175	 * Ensure the tv_sec value fits in t->seconds.
176	 */
177	if (sizeof(tv.tv_sec) > sizeof(t->seconds) &&
178	    ((tv.tv_sec | (unsigned int)-1) ^ (unsigned int)-1) != 0U)
179		return (ISC_R_RANGE);
180
181	t->seconds = tv.tv_sec;
182	t->nanoseconds = tv.tv_usec * NS_PER_US;
183
184	return (ISC_R_SUCCESS);
185}
186
187isc_result_t
188isc_time_nowplusinterval(isc_time_t *t, const isc_interval_t *i) {
189	struct timeval tv;
190	char strbuf[ISC_STRERRORSIZE];
191
192	REQUIRE(t != NULL);
193	REQUIRE(i != NULL);
194	INSIST(i->nanoseconds < NS_PER_S);
195
196	if (gettimeofday(&tv, NULL) == -1) {
197		isc__strerror(errno, strbuf, sizeof(strbuf));
198		UNEXPECTED_ERROR(__FILE__, __LINE__, "%s", strbuf);
199		return (ISC_R_UNEXPECTED);
200	}
201
202	/*
203	 * Does POSIX guarantee the signedness of tv_sec and tv_usec?  If not,
204	 * then this test will generate warnings for platforms on which it is
205	 * unsigned.  In any event, the chances of any of these problems
206	 * happening are pretty much zero, but since the libisc library ensures
207	 * certain things to be true ...
208	 */
209#if ISC_FIX_TV_USEC
210	fix_tv_usec(&tv);
211	if (tv.tv_sec < 0)
212		return (ISC_R_UNEXPECTED);
213#else
214	if (tv.tv_sec < 0 || tv.tv_usec < 0 || tv.tv_usec >= US_PER_S)
215		return (ISC_R_UNEXPECTED);
216#endif
217
218	/*
219	 * Ensure the resulting seconds value fits in the size of an
220	 * unsigned int.  (It is written this way as a slight optimization;
221	 * note that even if both values == INT_MAX, then when added
222	 * and getting another 1 added below the result is UINT_MAX.)
223	 */
224	if ((tv.tv_sec > INT_MAX || i->seconds > INT_MAX) &&
225	    ((long long)tv.tv_sec + i->seconds > UINT_MAX))
226		return (ISC_R_RANGE);
227
228	t->seconds = tv.tv_sec + i->seconds;
229	t->nanoseconds = tv.tv_usec * NS_PER_US + i->nanoseconds;
230	if (t->nanoseconds >= NS_PER_S) {
231		t->seconds++;
232		t->nanoseconds -= NS_PER_S;
233	}
234
235	return (ISC_R_SUCCESS);
236}
237
238int
239isc_time_compare(const isc_time_t *t1, const isc_time_t *t2) {
240	REQUIRE(t1 != NULL && t2 != NULL);
241	INSIST(t1->nanoseconds < NS_PER_S && t2->nanoseconds < NS_PER_S);
242
243	if (t1->seconds < t2->seconds)
244		return (-1);
245	if (t1->seconds > t2->seconds)
246		return (1);
247	if (t1->nanoseconds < t2->nanoseconds)
248		return (-1);
249	if (t1->nanoseconds > t2->nanoseconds)
250		return (1);
251	return (0);
252}
253
254isc_result_t
255isc_time_add(const isc_time_t *t, const isc_interval_t *i, isc_time_t *result)
256{
257	REQUIRE(t != NULL && i != NULL && result != NULL);
258	INSIST(t->nanoseconds < NS_PER_S && i->nanoseconds < NS_PER_S);
259
260	/*
261	 * Ensure the resulting seconds value fits in the size of an
262	 * unsigned int.  (It is written this way as a slight optimization;
263	 * note that even if both values == INT_MAX, then when added
264	 * and getting another 1 added below the result is UINT_MAX.)
265	 */
266	if ((t->seconds > INT_MAX || i->seconds > INT_MAX) &&
267	    ((long long)t->seconds + i->seconds > UINT_MAX))
268		return (ISC_R_RANGE);
269
270	result->seconds = t->seconds + i->seconds;
271	result->nanoseconds = t->nanoseconds + i->nanoseconds;
272	if (result->nanoseconds >= NS_PER_S) {
273		result->seconds++;
274		result->nanoseconds -= NS_PER_S;
275	}
276
277	return (ISC_R_SUCCESS);
278}
279
280isc_result_t
281isc_time_subtract(const isc_time_t *t, const isc_interval_t *i,
282		  isc_time_t *result)
283{
284	REQUIRE(t != NULL && i != NULL && result != NULL);
285	INSIST(t->nanoseconds < NS_PER_S && i->nanoseconds < NS_PER_S);
286
287	if ((unsigned int)t->seconds < i->seconds ||
288	    ((unsigned int)t->seconds == i->seconds &&
289	     t->nanoseconds < i->nanoseconds))
290	    return (ISC_R_RANGE);
291
292	result->seconds = t->seconds - i->seconds;
293	if (t->nanoseconds >= i->nanoseconds)
294		result->nanoseconds = t->nanoseconds - i->nanoseconds;
295	else {
296		result->nanoseconds = NS_PER_S - i->nanoseconds +
297			t->nanoseconds;
298		result->seconds--;
299	}
300
301	return (ISC_R_SUCCESS);
302}
303
304isc_uint64_t
305isc_time_microdiff(const isc_time_t *t1, const isc_time_t *t2) {
306	isc_uint64_t i1, i2, i3;
307
308	REQUIRE(t1 != NULL && t2 != NULL);
309	INSIST(t1->nanoseconds < NS_PER_S && t2->nanoseconds < NS_PER_S);
310
311	i1 = (isc_uint64_t)t1->seconds * NS_PER_S + t1->nanoseconds;
312	i2 = (isc_uint64_t)t2->seconds * NS_PER_S + t2->nanoseconds;
313
314	if (i1 <= i2)
315		return (0);
316
317	i3 = i1 - i2;
318
319	/*
320	 * Convert to microseconds.
321	 */
322	i3 = (i1 - i2) / NS_PER_US;
323
324	return (i3);
325}
326
327isc_uint32_t
328isc_time_seconds(const isc_time_t *t) {
329	REQUIRE(t != NULL);
330	INSIST(t->nanoseconds < NS_PER_S);
331
332	return ((isc_uint32_t)t->seconds);
333}
334
335isc_result_t
336isc_time_secondsastimet(const isc_time_t *t, time_t *secondsp) {
337	isc_uint64_t i;
338	time_t seconds;
339
340	REQUIRE(t != NULL);
341	INSIST(t->nanoseconds < NS_PER_S);
342
343	/*
344	 * Ensure that the number of seconds represented by t->seconds
345	 * can be represented by a time_t.  Since t->seconds is an unsigned
346	 * int and since time_t is mostly opaque, this is trickier than
347	 * it seems.  (This standardized opaqueness of time_t is *very*
348	 * frustrating; time_t is not even limited to being an integral
349	 * type.)
350	 *
351	 * The mission, then, is to avoid generating any kind of warning
352	 * about "signed versus unsigned" while trying to determine if the
353	 * the unsigned int t->seconds is out range for tv_sec, which is
354	 * pretty much only true if time_t is a signed integer of the same
355	 * size as the return value of isc_time_seconds.
356	 *
357	 * The use of the 64 bit integer ``i'' takes advantage of C's
358	 * conversion rules to either zero fill or sign extend the widened
359	 * type.
360	 *
361	 * Solaris 5.6 gives this warning about the left shift:
362	 *	warning: integer overflow detected: op "<<"
363	 * if the U(nsigned) qualifier is not on the 1.
364	 */
365	seconds = (time_t)t->seconds;
366
367	INSIST(sizeof(unsigned int) == sizeof(isc_uint32_t));
368	INSIST(sizeof(time_t) >= sizeof(isc_uint32_t));
369
370	if (sizeof(time_t) == sizeof(isc_uint32_t) &&	       /* Same size. */
371	    (time_t)0.5 != 0.5 &&	       /* Not a floating point type. */
372	    (i = (time_t)-1) != 4294967295u &&		       /* Is signed. */
373	    (seconds &
374	     (1U << (sizeof(time_t) * CHAR_BIT - 1))) != 0U) {   /* Negative. */
375		/*
376		 * This UNUSED() is here to shut up the IRIX compiler:
377		 *	variable "i" was set but never used
378		 * when the value of i *was* used in the third test.
379		 * (Let's hope the compiler got the actual test right.)
380		 */
381		UNUSED(i);
382		return (ISC_R_RANGE);
383	}
384
385	*secondsp = seconds;
386
387	return (ISC_R_SUCCESS);
388}
389
390isc_uint32_t
391isc_time_nanoseconds(const isc_time_t *t) {
392	REQUIRE(t != NULL);
393
394	ENSURE(t->nanoseconds < NS_PER_S);
395
396	return ((isc_uint32_t)t->nanoseconds);
397}
398
399void
400isc_time_formattimestamp(const isc_time_t *t, char *buf, unsigned int len) {
401	time_t now;
402	unsigned int flen;
403
404	REQUIRE(len > 0);
405
406	now = (time_t) t->seconds;
407	flen = strftime(buf, len, "%d-%b-%Y %X", localtime(&now));
408	INSIST(flen < len);
409	if (flen != 0)
410		snprintf(buf + flen, len - flen,
411			 ".%03u", t->nanoseconds / 1000000);
412	else
413		snprintf(buf, len, "99-Bad-9999 99:99:99.999");
414}
415
416void
417isc_time_formathttptimestamp(const isc_time_t *t, char *buf, unsigned int len) {
418	time_t now;
419	unsigned int flen;
420
421	REQUIRE(len > 0);
422
423	now = (time_t)t->seconds;
424	flen = strftime(buf, len, "%a, %d %b %Y %H:%M:%S GMT", gmtime(&now));
425	INSIST(flen < len);
426}
427
428void
429isc_time_formatISO8601(const isc_time_t *t, char *buf, unsigned int len) {
430	time_t now;
431	unsigned int flen;
432
433	REQUIRE(len > 0);
434
435	now = (time_t)t->seconds;
436	flen = strftime(buf, len, "%Y-%m-%dT%H:%M:%SZ", gmtime(&now));
437	INSIST(flen < len);
438}
439