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PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

1 files changed, 224 insertions, 0 deletions

diff --git a/pkg/abi/linux/time.go b/pkg/abi/linux/time.go
new file mode 100644
index 000000000..9109a2848
--- /dev/null
+++ b/pkg/abi/linux/time.go
@@ -0,0 +1,224 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package linux
+
+import (
+	"math"
+	"time"
+)
+
+const (
+	// ClockTick is the length of time represented by a single clock tick, as
+	// used by times(2) and /proc/[pid]/stat.
+	ClockTick = time.Second / CLOCKS_PER_SEC
+
+	// CLOCKS_PER_SEC is the number of ClockTicks per second.
+	//
+	// Linux defines this to be 100 on most architectures, irrespective of
+	// CONFIG_HZ. Userspace obtains the value through sysconf(_SC_CLK_TCK),
+	// which uses the AT_CLKTCK entry in the auxiliary vector if one is
+	// provided, and assumes 100 otherwise (glibc:
+	// sysdeps/posix/sysconf.c:__sysconf() =>
+	// sysdeps/unix/sysv/linux/getclktck.c, elf/dl-support.c:_dl_aux_init()).
+	//
+	// Not to be confused with POSIX CLOCKS_PER_SEC, as used by clock(3); "XSI
+	// requires that [POSIX] CLOCKS_PER_SEC equals 1000000 independent of the
+	// actual resolution" - clock(3).
+	CLOCKS_PER_SEC = 100
+)
+
+// CPU clock types for use with clock_gettime(2) et al.
+//
+// The 29 most significant bits of a 32 bit clock ID are either a PID or a FD.
+//
+// Bits 1 and 0 give the type: PROF=0, VIRT=1, SCHED=2, or FD=3.
+//
+// Bit 2 indicates whether a cpu clock refers to a thread or a process.
+const (
+	CPUCLOCK_PROF  = 0
+	CPUCLOCK_VIRT  = 1
+	CPUCLOCK_SCHED = 2
+	CPUCLOCK_MAX   = 3
+	CLOCKFD        = CPUCLOCK_MAX
+
+	CPUCLOCK_CLOCK_MASK     = 3
+	CPUCLOCK_PERTHREAD_MASK = 4
+)
+
+// Clock identifiers for use with clock_gettime(2), clock_getres(2),
+// clock_nanosleep(2).
+const (
+	CLOCK_REALTIME           = 0
+	CLOCK_MONOTONIC          = 1
+	CLOCK_PROCESS_CPUTIME_ID = 2
+	CLOCK_THREAD_CPUTIME_ID  = 3
+	CLOCK_MONOTONIC_RAW      = 4
+	CLOCK_REALTIME_COARSE    = 5
+	CLOCK_MONOTONIC_COARSE   = 6
+	CLOCK_BOOTTIME           = 7
+	CLOCK_REALTIME_ALARM     = 8
+	CLOCK_BOOTTIME_ALARM     = 9
+)
+
+// Flags for clock_nanosleep(2).
+const (
+	TIMER_ABSTIME = 1
+)
+
+// Flags for timerfd syscalls (timerfd_create(2), timerfd_settime(2)).
+const (
+	// TFD_CLOEXEC is a timerfd_create flag.
+	TFD_CLOEXEC = O_CLOEXEC
+
+	// TFD_NONBLOCK is a timerfd_create flag.
+	TFD_NONBLOCK = O_NONBLOCK
+
+	// TFD_TIMER_ABSTIME is a timerfd_settime flag.
+	TFD_TIMER_ABSTIME = 1
+)
+
+// The safe number of seconds you can represent by int64.
+const maxSecInDuration = math.MaxInt64 / int64(time.Second)
+
+// TimeT represents time_t in <time.h>. It represents time in seconds.
+type TimeT int64
+
+// NsecToTimeT translates nanoseconds to TimeT (seconds).
+func NsecToTimeT(nsec int64) TimeT {
+	return TimeT(nsec / 1e9)
+}
+
+// Timespec represents struct timespec in <time.h>.
+type Timespec struct {
+	Sec  int64
+	Nsec int64
+}
+
+// Unix returns the second and nanosecond.
+func (ts Timespec) Unix() (sec int64, nsec int64) {
+	return int64(ts.Sec), int64(ts.Nsec)
+}
+
+// ToTime returns the Go time.Time representation.
+func (ts Timespec) ToTime() time.Time {
+	return time.Unix(ts.Sec, ts.Nsec)
+}
+
+// ToNsec returns the nanosecond representation.
+func (ts Timespec) ToNsec() int64 {
+	return int64(ts.Sec)*1e9 + int64(ts.Nsec)
+}
+
+// ToNsecCapped returns the safe nanosecond representation.
+func (ts Timespec) ToNsecCapped() int64 {
+	if ts.Sec > maxSecInDuration {
+		return math.MaxInt64
+	}
+	return ts.ToNsec()
+}
+
+// ToDuration returns the safe nanosecond representation as time.Duration.
+func (ts Timespec) ToDuration() time.Duration {
+	return time.Duration(ts.ToNsecCapped())
+}
+
+// Valid returns whether the timespec contains valid values.
+func (ts Timespec) Valid() bool {
+	return !(ts.Sec < 0 || ts.Nsec < 0 || ts.Nsec >= int64(time.Second))
+}
+
+// NsecToTimespec translates nanoseconds to Timespec.
+func NsecToTimespec(nsec int64) (ts Timespec) {
+	ts.Sec = nsec / 1e9
+	ts.Nsec = nsec % 1e9
+	return
+}
+
+// DurationToTimespec translates time.Duration to Timespec.
+func DurationToTimespec(dur time.Duration) Timespec {
+	return NsecToTimespec(dur.Nanoseconds())
+}
+
+// SizeOfTimeval is the size of a Timeval struct in bytes.
+const SizeOfTimeval = 16
+
+// Timeval represents struct timeval in <time.h>.
+type Timeval struct {
+	Sec  int64
+	Usec int64
+}
+
+// ToNsecCapped returns the safe nanosecond representation.
+func (tv Timeval) ToNsecCapped() int64 {
+	if tv.Sec > maxSecInDuration {
+		return math.MaxInt64
+	}
+	return int64(tv.Sec)*1e9 + int64(tv.Usec)*1e3
+}
+
+// ToDuration returns the safe nanosecond representation as a time.Duration.
+func (tv Timeval) ToDuration() time.Duration {
+	return time.Duration(tv.ToNsecCapped())
+}
+
+// ToTime returns the Go time.Time representation.
+func (tv Timeval) ToTime() time.Time {
+	return time.Unix(tv.Sec, tv.Usec*1e3)
+}
+
+// NsecToTimeval translates nanosecond to Timeval.
+func NsecToTimeval(nsec int64) (tv Timeval) {
+	nsec += 999 // round up to microsecond
+	tv.Sec = nsec / 1e9
+	tv.Usec = nsec % 1e9 / 1e3
+	return
+}
+
+// DurationToTimeval translates time.Duration to Timeval.
+func DurationToTimeval(dur time.Duration) Timeval {
+	return NsecToTimeval(dur.Nanoseconds())
+}
+
+// Itimerspec represents struct itimerspec in <time.h>.
+type Itimerspec struct {
+	Interval Timespec
+	Value    Timespec
+}
+
+// ItimerVal mimics the following struct in <sys/time.h>
+//   struct itimerval {
+//     struct timeval it_interval; /* next value */
+//     struct timeval it_value;    /* current value */
+//   };
+type ItimerVal struct {
+	Interval Timeval
+	Value    Timeval
+}
+
+// ClockT represents type clock_t.
+type ClockT int64
+
+// ClockTFromDuration converts time.Duration to clock_t.
+func ClockTFromDuration(d time.Duration) ClockT {
+	return ClockT(d / ClockTick)
+}
+
+// Tms represents struct tms, used by times(2).
+type Tms struct {
+	UTime  ClockT
+	STime  ClockT
+	CUTime ClockT
+	CSTime ClockT
+}