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clock_gettime-xnu.c
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clock_gettime-xnu.c
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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2022 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/calls/struct/timespec.internal.h"
#include "libc/calls/struct/timeval.h"
#include "libc/calls/struct/timeval.internal.h"
#include "libc/errno.h"
#include "libc/macros.internal.h"
#include "libc/sysv/consts/clock.h"
#ifdef __x86_64__
#define CTL_KERN 1
#define KERN_BOOTTIME 21
int sys_clock_gettime_xnu(int clock, struct timespec *ts) {
long ax, dx;
if (clock == CLOCK_REALTIME) {
// invoke the system call
//
// int gettimeofday(struct timeval *tp,
// struct timezone *tzp,
// uint64_t *mach_absolute_time);
//
// as follows
//
// ax, dx = gettimeofday(&ts, 0, 0);
//
// to support multiple calling conventions
//
// 1. new xnu returns *ts in memory via rdi
// 2. old xnu returns *ts in rax:rdx regs
//
// we assume this system call always succeeds
if (ts) {
asm volatile("syscall"
: "=a"(ax), "=d"(dx)
: "0"(0x2000000 | 116), "D"(ts), "S"(0), "1"(0)
: "rcx", "r8", "r9", "r10", "r11", "memory");
if (ax) {
ts->tv_sec = ax;
ts->tv_nsec = dx;
}
ts->tv_nsec *= 1000;
}
return 0;
} else if (clock == CLOCK_MONOTONIC) {
if (!ts)
return 0;
return sys_clock_gettime_mono(ts);
} else if (clock == CLOCK_BOOTTIME) {
struct timeval x;
size_t n = sizeof(x);
int mib[] = {CTL_KERN, KERN_BOOTTIME};
if (sysctl(mib, ARRAYLEN(mib), &x, &n, 0, 0) == -1)
return -1;
if (ts)
*ts = timeval_totimespec(timeval_sub(timeval_real(), x));
return 0;
} else {
return -EINVAL;
}
}
#endif /* __x86_64__ */