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gen/clock_gettime.c /dev/null Libc-1158.20.4
--- /dev/null
+++ Libc/Libc-1158.20.4/gen/clock_gettime.c
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+/*
+ * Copyright (c) 2016 Apple Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ * 
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+#include <errno.h>
+#include <stdatomic.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/sysctl.h>
+#include <mach/mach_error.h>
+#include <mach/mach_time.h>
+#include <os/base_private.h>
+
+extern uint64_t __thread_selfusage(void);
+
+#define timeval2nsec(tv) (tv.tv_sec * NSEC_PER_SEC + tv.tv_usec * NSEC_PER_USEC)
+
+static uint64_t
+_boottime_fallback_usec(void)
+{
+    struct timeval tv;
+    size_t len = sizeof(tv);
+    int ret = sysctlbyname("kern.boottime", &tv, &len, NULL, 0);
+    if (ret == -1) return 0;
+    return (uint64_t)tv.tv_sec * USEC_PER_SEC + (uint64_t)tv.tv_usec;
+}
+
+static int
+_mach_boottime_usec(uint64_t *boottime, struct timeval *realtime)
+{
+    uint64_t bt1 = 0, bt2 = 0;
+    int ret;
+    do {
+        bt1 = mach_boottime_usec();
+        if (os_slowpath(bt1 == 0)) bt1 = _boottime_fallback_usec();
+
+        atomic_thread_fence(memory_order_seq_cst);
+
+        ret = gettimeofday(realtime, NULL);
+        if (ret != 0) return ret;
+
+        atomic_thread_fence(memory_order_seq_cst);
+
+        bt2 = mach_boottime_usec();
+        if (os_slowpath(bt2 == 0)) bt2 = _boottime_fallback_usec();
+    } while (os_slowpath(bt1 != bt2));
+    *boottime = bt1;
+    return 0;
+}
+
+uint64_t
+clock_gettime_nsec_np(clockid_t clock_id)
+{
+    switch(clock_id){
+    case CLOCK_REALTIME: {
+        struct timeval tv;
+        int ret = gettimeofday(&tv, NULL);
+        if (ret) return 0;
+        return timeval2nsec(tv);
+    }
+    case CLOCK_MONOTONIC: {
+        struct timeval tv;
+        uint64_t boottime;
+        int ret = _mach_boottime_usec(&boottime, &tv);
+        if (ret) return 0;
+        boottime *= NSEC_PER_USEC;
+        return timeval2nsec(tv) - boottime;
+    }
+    case CLOCK_PROCESS_CPUTIME_ID: {
+        struct rusage ru;
+        int ret = getrusage(RUSAGE_SELF, &ru);
+        if (ret) return 0;
+        return timeval2nsec(ru.ru_utime) + timeval2nsec(ru.ru_stime);
+    }
+    default:
+        // calls that use mach_absolute_time units fall through into a common path
+        break;
+    }
+
+    // Mach Absolute Time unit-based calls
+    mach_timebase_info_data_t tb_info;
+    if (mach_timebase_info(&tb_info)) return 0;
+    uint64_t mach_time;
+
+    switch(clock_id){
+    case CLOCK_MONOTONIC_RAW:
+        mach_time = mach_continuous_time();
+        break;
+    case CLOCK_MONOTONIC_RAW_APPROX:
+        mach_time = mach_continuous_approximate_time();
+        break;
+    case CLOCK_UPTIME_RAW:
+        mach_time = mach_absolute_time();
+        break;
+    case CLOCK_UPTIME_RAW_APPROX:
+        mach_time = mach_approximate_time();
+        break;
+    case CLOCK_THREAD_CPUTIME_ID:
+        mach_time = __thread_selfusage();
+        break;
+    default:
+        errno = EINVAL;
+        return 0;
+    }
+
+    return (mach_time * tb_info.numer) / tb_info.denom;
+}
+
+int
+clock_gettime(clockid_t clk_id, struct timespec *tp)
+{
+    switch(clk_id){
+    case CLOCK_REALTIME: {
+        struct timeval tv;
+        int ret = gettimeofday(&tv, NULL);
+        TIMEVAL_TO_TIMESPEC(&tv, tp);
+        return ret;
+    }
+    case CLOCK_MONOTONIC: {
+        struct timeval tv;
+        uint64_t boottime_usec;
+        int ret = _mach_boottime_usec(&boottime_usec, &tv);
+        struct timeval boottime = {
+            .tv_sec = boottime_usec / USEC_PER_SEC,
+            .tv_usec = boottime_usec % USEC_PER_SEC
+        };
+        timersub(&tv, &boottime, &tv);
+        TIMEVAL_TO_TIMESPEC(&tv, tp);
+        return ret;
+    }
+    case CLOCK_PROCESS_CPUTIME_ID: {
+        struct rusage ru;
+        int ret = getrusage(RUSAGE_SELF, &ru);
+        timeradd(&ru.ru_utime, &ru.ru_stime, &ru.ru_utime);
+        TIMEVAL_TO_TIMESPEC(&ru.ru_utime, tp);
+        return ret;
+    }
+    case CLOCK_MONOTONIC_RAW:
+    case CLOCK_MONOTONIC_RAW_APPROX:
+    case CLOCK_UPTIME_RAW:
+    case CLOCK_UPTIME_RAW_APPROX:
+    case CLOCK_THREAD_CPUTIME_ID: {
+        uint64_t ns = clock_gettime_nsec_np(clk_id);
+        if (!ns) return -1;
+
+        tp->tv_sec = ns/NSEC_PER_SEC;
+        tp->tv_nsec = ns % NSEC_PER_SEC;
+        return 0;
+    }
+    default:
+        errno = EINVAL;
+        return -1;
+    }
+}
+
+int
+clock_getres(clockid_t clk_id, struct timespec *res)
+{
+    switch(clk_id){
+    case CLOCK_REALTIME:
+    case CLOCK_MONOTONIC:
+    case CLOCK_PROCESS_CPUTIME_ID:
+        res->tv_nsec = NSEC_PER_USEC;
+        res->tv_sec = 0;
+        return 0;
+
+    case CLOCK_MONOTONIC_RAW:
+    case CLOCK_MONOTONIC_RAW_APPROX:
+    case CLOCK_UPTIME_RAW:
+    case CLOCK_UPTIME_RAW_APPROX:
+    case CLOCK_THREAD_CPUTIME_ID: {
+        mach_timebase_info_data_t tb_info;
+        if (mach_timebase_info(&tb_info)){
+            return -1;
+        }
+        res->tv_nsec = tb_info.numer / tb_info.denom + (tb_info.numer % tb_info.denom != 0);
+        res->tv_sec = 0;
+        return 0;
+    }
+
+    default:
+        errno = EINVAL;
+        return -1;
+    }
+}
+
+int
+clock_settime(clockid_t clk_id, const struct timespec *tp)
+{
+    switch(clk_id){
+    case CLOCK_REALTIME: {
+        struct timeval tv;
+        TIMESPEC_TO_TIMEVAL(&tv,tp)
+        return settimeofday(&tv, NULL);
+    }
+    default:
+        errno = EINVAL;
+        return -1;
+    }
+}