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
|
/* MIT License
*
* Copyright (c) 2008 Daniel Stenberg
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* SPDX-License-Identifier: MIT
*/
#include "ares_private.h"
#if defined(_WIN32) && !defined(MSDOS)
void ares_tvnow(ares_timeval_t *now)
{
/* QueryPerformanceCounters() has been around since Windows 2000, though
* significant fixes were made in later versions. Documentation states
* 1 microsecond or better resolution with a rollover not less than 100 years.
* This differs from GetTickCount{64}() which has a resolution between 10 and
* 16 ms. */
LARGE_INTEGER freq;
LARGE_INTEGER current;
/* Not sure how long it takes to get the frequency, I see it recommended to
* cache it */
QueryPerformanceFrequency(&freq);
QueryPerformanceCounter(¤t);
now->sec = current.QuadPart / freq.QuadPart;
/* We want to prevent overflows so we get the remainder, then multiply to
* microseconds before dividing */
now->usec = (unsigned int)(((current.QuadPart % freq.QuadPart) * 1000000) /
freq.QuadPart);
}
#elif defined(HAVE_CLOCK_GETTIME_MONOTONIC)
void ares_tvnow(ares_timeval_t *now)
{
/* clock_gettime() is guaranteed to be increased monotonically when the
* monotonic clock is queried. Time starting point is unspecified, it
* could be the system start-up time, the Epoch, or something else,
* in any case the time starting point does not change once that the
* system has started up. */
struct timespec tsnow;
if (clock_gettime(CLOCK_MONOTONIC, &tsnow) == 0) {
now->sec = (ares_int64_t)tsnow.tv_sec;
now->usec = (unsigned int)(tsnow.tv_nsec / 1000);
} else {
/* LCOV_EXCL_START: FallbackCode */
struct timeval tv;
(void)gettimeofday(&tv, NULL);
now->sec = (ares_int64_t)tv.tv_sec;
now->usec = (unsigned int)tv.tv_usec;
/* LCOV_EXCL_STOP */
}
}
#elif defined(HAVE_GETTIMEOFDAY)
void ares_tvnow(ares_timeval_t *now)
{
/* gettimeofday() is not granted to be increased monotonically, due to
* clock drifting and external source time synchronization it can jump
* forward or backward in time. */
struct timeval tv;
(void)gettimeofday(&tv, NULL);
now->sec = (ares_int64_t)tv.tv_sec;
now->usec = (unsigned int)tv.tv_usec;
}
#else
# error missing sub-second time retrieval function
#endif
|
