1 /*
2 *
3 * Copyright 2015 gRPC authors.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 */
18
19 #include <grpc/support/port_platform.h>
20
21 #include "src/core/lib/gpr/time_precise.h"
22
23 #ifdef GPR_POSIX_TIME
24
25 #include <stdlib.h>
26 #include <time.h>
27 #include <unistd.h>
28 #ifdef __linux__
29 #include <sys/syscall.h>
30 #endif
31 #include <grpc/support/atm.h>
32 #include <grpc/support/log.h>
33 #include <grpc/support/time.h>
34
timespec_from_gpr(gpr_timespec gts)35 static struct timespec timespec_from_gpr(gpr_timespec gts) {
36 struct timespec rv;
37 if (sizeof(time_t) < sizeof(int64_t)) {
38 /* fine to assert, as this is only used in gpr_sleep_until */
39 GPR_ASSERT(gts.tv_sec <= INT32_MAX && gts.tv_sec >= INT32_MIN);
40 }
41 rv.tv_sec = static_cast<time_t>(gts.tv_sec);
42 rv.tv_nsec = gts.tv_nsec;
43 return rv;
44 }
45
46 #if _POSIX_TIMERS > 0 || defined(__OpenBSD__)
gpr_from_timespec(struct timespec ts,gpr_clock_type clock_type)47 static gpr_timespec gpr_from_timespec(struct timespec ts,
48 gpr_clock_type clock_type) {
49 /*
50 * timespec.tv_sec can have smaller size than gpr_timespec.tv_sec,
51 * but we are only using this function to implement gpr_now
52 * so there's no need to handle "infinity" values.
53 */
54 gpr_timespec rv;
55 rv.tv_sec = ts.tv_sec;
56 rv.tv_nsec = static_cast<int32_t>(ts.tv_nsec);
57 rv.clock_type = clock_type;
58 return rv;
59 }
60
61 /** maps gpr_clock_type --> clockid_t for clock_gettime */
62 static const clockid_t clockid_for_gpr_clock[] = {CLOCK_MONOTONIC,
63 CLOCK_REALTIME};
64
gpr_time_init(void)65 void gpr_time_init(void) { gpr_precise_clock_init(); }
66
now_impl(gpr_clock_type clock_type)67 static gpr_timespec now_impl(gpr_clock_type clock_type) {
68 struct timespec now;
69 GPR_ASSERT(clock_type != GPR_TIMESPAN);
70 if (clock_type == GPR_CLOCK_PRECISE) {
71 gpr_timespec ret;
72 gpr_precise_clock_now(&ret);
73 return ret;
74 } else {
75 #if defined(GPR_BACKWARDS_COMPATIBILITY_MODE) && defined(__linux__)
76 /* avoid ABI problems by invoking syscalls directly */
77 syscall(SYS_clock_gettime, clockid_for_gpr_clock[clock_type], &now);
78 #else
79 clock_gettime(clockid_for_gpr_clock[clock_type], &now);
80 #endif
81 return gpr_from_timespec(now, clock_type);
82 }
83 }
84 #else
85 /* For some reason Apple's OSes haven't implemented clock_gettime. */
86
87 #include <mach/mach.h>
88 #include <mach/mach_time.h>
89 #include <sys/time.h>
90
91 static double g_time_scale;
92 static uint64_t g_time_start;
93
gpr_time_init(void)94 void gpr_time_init(void) {
95 mach_timebase_info_data_t tb = {0, 1};
96 gpr_precise_clock_init();
97 mach_timebase_info(&tb);
98 g_time_scale = tb.numer;
99 g_time_scale /= tb.denom;
100 g_time_start = mach_absolute_time();
101 }
102
now_impl(gpr_clock_type clock)103 static gpr_timespec now_impl(gpr_clock_type clock) {
104 gpr_timespec now;
105 struct timeval now_tv;
106 double now_dbl;
107
108 now.clock_type = clock;
109 switch (clock) {
110 case GPR_CLOCK_REALTIME:
111 // gettimeofday(...) function may return with a value whose tv_usec is
112 // greater than 1e6 on iOS The case is resolved with the guard at end of
113 // this function.
114 gettimeofday(&now_tv, nullptr);
115 now.tv_sec = now_tv.tv_sec;
116 now.tv_nsec = now_tv.tv_usec * 1000;
117 break;
118 case GPR_CLOCK_MONOTONIC:
119 now_dbl = ((double)(mach_absolute_time() - g_time_start)) * g_time_scale;
120 now.tv_sec = (int64_t)(now_dbl * 1e-9);
121 now.tv_nsec = (int32_t)(now_dbl - ((double)now.tv_sec) * 1e9);
122 break;
123 case GPR_CLOCK_PRECISE:
124 gpr_precise_clock_now(&now);
125 break;
126 case GPR_TIMESPAN:
127 abort();
128 }
129
130 // Guard the tv_nsec field in valid range for all clock types
131 while (GPR_UNLIKELY(now.tv_nsec >= 1e9)) {
132 now.tv_sec++;
133 now.tv_nsec -= 1e9;
134 }
135 while (GPR_UNLIKELY(now.tv_nsec < 0)) {
136 now.tv_sec--;
137 now.tv_nsec += 1e9;
138 }
139
140 return now;
141 }
142 #endif
143
144 gpr_timespec (*gpr_now_impl)(gpr_clock_type clock_type) = now_impl;
145
146 #ifdef GPR_LOW_LEVEL_COUNTERS
147 gpr_atm gpr_now_call_count;
148 #endif
gpr_now(gpr_clock_type clock_type)149 gpr_timespec gpr_now(gpr_clock_type clock_type) {
150 #ifdef GPR_LOW_LEVEL_COUNTERS
151 __atomic_fetch_add(&gpr_now_call_count, 1, __ATOMIC_RELAXED);
152 #endif
153 // validate clock type
154 GPR_ASSERT(clock_type == GPR_CLOCK_MONOTONIC ||
155 clock_type == GPR_CLOCK_REALTIME ||
156 clock_type == GPR_CLOCK_PRECISE);
157 gpr_timespec ts = gpr_now_impl(clock_type);
158 // tv_nsecs must be in the range [0, 1e9).
159 GPR_ASSERT(ts.tv_nsec >= 0 && ts.tv_nsec < 1e9);
160 return ts;
161 }
162
gpr_sleep_until(gpr_timespec until)163 void gpr_sleep_until(gpr_timespec until) {
164 gpr_timespec now;
165 gpr_timespec delta;
166 struct timespec delta_ts;
167 int ns_result;
168
169 for (;;) {
170 /* We could simplify by using clock_nanosleep instead, but it might be
171 * slightly less portable. */
172 now = gpr_now(until.clock_type);
173 if (gpr_time_cmp(until, now) <= 0) {
174 return;
175 }
176
177 delta = gpr_time_sub(until, now);
178 delta_ts = timespec_from_gpr(delta);
179 ns_result = nanosleep(&delta_ts, nullptr);
180 if (ns_result == 0) {
181 break;
182 }
183 }
184 }
185
186 #endif /* GPR_POSIX_TIME */
187