syscall: unify NsecToTime{spec,val}, fix for times < 1970

All the implementations of NsecToTimespec and NsecToTimeval were the
same other than types. Write a single version that uses
GOARCH/GOOS-specific setTimespec and setTimeval functions to handle the
types.

The logic in NsecToTimespec and NsecToTimeval caused times before 1970
to have a negative usec/nsec. The Linux kernel requires that usec
contain a positive number; for consistency, we do this for both
NsecToTimespec and NsecToTimeval.

Change-Id: I525eaba2e7cdb00cb57fa00182dabf19fec298ae
Reviewed-on: https://go-review.googlesource.com/30826
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

src/syscall/syscall_darwin_386.go

@@ -6,17 +6,12 @@ package syscall
 
 import "unsafe"
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = int32(nsec / 1e9)
-	ts.Nsec = int32(nsec % 1e9)
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: int32(sec), Nsec: int32(nsec)}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Usec = int32(nsec % 1e9 / 1e3)
-	tv.Sec = int32(nsec / 1e9)
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: int32(sec), Usec: int32(usec)}
 }
 
 //sysnb	gettimeofday(tp *Timeval) (sec int32, usec int32, err error)

src/syscall/syscall_darwin_amd64.go

@@ -6,17 +6,12 @@ package syscall
 
 import "unsafe"
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = nsec / 1e9
-	ts.Nsec = nsec % 1e9
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: nsec}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Usec = int32(nsec % 1e9 / 1e3)
-	tv.Sec = int64(nsec / 1e9)
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: int32(usec)}
 }
 
 //sysnb	gettimeofday(tp *Timeval) (sec int64, usec int32, err error)

src/syscall/syscall_darwin_arm.go

@@ -6,17 +6,12 @@ package syscall
 
 import "unsafe"
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = int32(nsec / 1e9)
-	ts.Nsec = int32(nsec % 1e9)
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: int32(sec), Nsec: int32(nsec)}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Usec = int32(nsec % 1e9 / 1e3)
-	tv.Sec = int32(nsec / 1e9)
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: int32(sec), Usec: int32(usec)}
 }
 
 //sysnb	gettimeofday(tp *Timeval) (sec int32, usec int32, err error)

src/syscall/syscall_dragonfly_amd64.go

@@ -6,17 +6,12 @@ package syscall
 
 import "unsafe"
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = nsec / 1e9
-	ts.Nsec = nsec % 1e9
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: nsec}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Usec = nsec % 1e9 / 1e3
-	tv.Sec = int64(nsec / 1e9)
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: usec}
 }
 
 func SetKevent(k *Kevent_t, fd, mode, flags int) {

src/syscall/syscall_freebsd_386.go

@@ -6,17 +6,12 @@ package syscall
 
 import "unsafe"
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = int32(nsec / 1e9)
-	ts.Nsec = int32(nsec % 1e9)
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: int32(sec), Nsec: int32(nsec)}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Usec = int32(nsec % 1e9 / 1e3)
-	tv.Sec = int32(nsec / 1e9)
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: int32(sec), Usec: int32(usec)}
 }
 
 func SetKevent(k *Kevent_t, fd, mode, flags int) {

src/syscall/syscall_freebsd_amd64.go

@@ -6,17 +6,12 @@ package syscall
 
 import "unsafe"
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = nsec / 1e9
-	ts.Nsec = nsec % 1e9
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: nsec}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Usec = nsec % 1e9 / 1e3
-	tv.Sec = int64(nsec / 1e9)
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: usec}
 }
 
 func SetKevent(k *Kevent_t, fd, mode, flags int) {

src/syscall/syscall_freebsd_arm.go

@@ -6,17 +6,12 @@ package syscall
 
 import "unsafe"
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = nsec / 1e9
-	ts.Nsec = int32(nsec % 1e9)
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: int32(nsec)}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Usec = int32(nsec % 1e9 / 1e3)
-	tv.Sec = nsec / 1e9
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: int32(usec)}
 }
 
 func SetKevent(k *Kevent_t, fd, mode, flags int) {

src/syscall/syscall_linux_386.go

@@ -14,17 +14,12 @@ const (
 	_SYS_getdents = SYS_GETDENTS64
 )
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = int32(nsec / 1e9)
-	ts.Nsec = int32(nsec % 1e9)
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: int32(sec), Nsec: int32(nsec)}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Sec = int32(nsec / 1e9)
-	tv.Usec = int32(nsec % 1e9 / 1e3)
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: int32(sec), Usec: int32(usec)}
 }
 
 //sysnb	pipe(p *[2]_C_int) (err error)

src/syscall/syscall_linux_amd64.go

@@ -84,17 +84,12 @@ func Time(t *Time_t) (tt Time_t, err error) {
 	return Time_t(tv.Sec), nil
 }
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = nsec / 1e9
-	ts.Nsec = nsec % 1e9
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: nsec}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Sec = nsec / 1e9
-	tv.Usec = nsec % 1e9 / 1e3
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: usec}
 }
 
 //sysnb	pipe(p *[2]_C_int) (err error)

src/syscall/syscall_linux_arm.go

@@ -11,17 +11,12 @@ const (
 	_SYS_getdents = SYS_GETDENTS64
 )
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = int32(nsec / 1e9)
-	ts.Nsec = int32(nsec % 1e9)
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: int32(sec), Nsec: int32(nsec)}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Sec = int32(nsec / 1e9)
-	tv.Usec = int32(nsec % 1e9 / 1e3)
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: int32(sec), Usec: int32(usec)}
 }
 
 func Pipe(p []int) (err error) {

src/syscall/syscall_linux_arm64.go

@@ -71,17 +71,12 @@ func Lstat(path string, stat *Stat_t) (err error) {
 //sysnb	Gettimeofday(tv *Timeval) (err error)
 //sysnb	Time(t *Time_t) (tt Time_t, err error)
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = nsec / 1e9
-	ts.Nsec = nsec % 1e9
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: nsec}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Sec = nsec / 1e9
-	tv.Usec = nsec % 1e9 / 1e3
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: usec}
 }
 
 func Pipe(p []int) (err error) {

src/syscall/syscall_linux_mips64x.go

@@ -79,17 +79,12 @@ func Time(t *Time_t) (tt Time_t, err error) {
 	return Time_t(tv.Sec), nil
 }
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = nsec / 1e9
-	ts.Nsec = nsec % 1e9
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: nsec}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Sec = nsec / 1e9
-	tv.Usec = nsec % 1e9 / 1e3
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: usec}
 }
 
 func Pipe(p []int) (err error) {

src/syscall/syscall_linux_ppc64x.go

@@ -67,17 +67,12 @@ const (
 //sysnb	Gettimeofday(tv *Timeval) (err error)
 //sysnb	Time(t *Time_t) (tt Time_t, err error)
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = nsec / 1e9
-	ts.Nsec = nsec % 1e9
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: nsec}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Sec = nsec / 1e9
-	tv.Usec = nsec % 1e9 / 1e3
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: usec}
 }
 
 func Pipe(p []int) (err error) {

src/syscall/syscall_linux_s390x.go

@@ -58,17 +58,12 @@ func Time(t *Time_t) (tt Time_t, err error) {
 	return Time_t(tv.Sec), nil
 }
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = nsec / 1e9
-	ts.Nsec = nsec % 1e9
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: nsec}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Sec = nsec / 1e9
-	tv.Usec = nsec % 1e9 / 1e3
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: usec}
 }
 
 func Pipe(p []int) (err error) {

src/syscall/syscall_nacl_386.go

@@ -14,15 +14,10 @@ type Timeval struct {
 	Usec int32
 }
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = int64(nsec / 1e9)
-	ts.Nsec = int32(nsec % 1e9)
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: int32(nsec)}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Usec = int32(nsec % 1e9 / 1e3)
-	tv.Sec = int64(nsec / 1e9)
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: int32(usec)}
 }

src/syscall/syscall_nacl_amd64p32.go

@@ -14,15 +14,10 @@ type Timeval struct {
 	Usec int32
 }
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = int64(nsec / 1e9)
-	ts.Nsec = int32(nsec % 1e9)
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: int32(nsec)}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Usec = int32(nsec % 1e9 / 1e3)
-	tv.Sec = int64(nsec / 1e9)
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: int32(usec)}
 }

src/syscall/syscall_nacl_arm.go

@@ -14,15 +14,10 @@ type Timeval struct {
 	Usec int32
 }
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = int64(nsec / 1e9)
-	ts.Nsec = int32(nsec % 1e9)
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: int32(nsec)}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Usec = int32(nsec % 1e9 / 1e3)
-	tv.Sec = int64(nsec / 1e9)
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: int32(usec)}
 }

src/syscall/syscall_netbsd_386.go

@@ -4,17 +4,12 @@
 
 package syscall
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = int64(nsec / 1e9)
-	ts.Nsec = int32(nsec % 1e9)
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: int32(nsec)}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Usec = int32(nsec % 1e9 / 1e3)
-	tv.Sec = int64(nsec / 1e9)
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: int32(usec)}
 }
 
 func SetKevent(k *Kevent_t, fd, mode, flags int) {

src/syscall/syscall_netbsd_amd64.go

@@ -4,17 +4,12 @@
 
 package syscall
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = int64(nsec / 1e9)
-	ts.Nsec = int64(nsec % 1e9)
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: nsec}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Usec = int32(nsec % 1e9 / 1e3)
-	tv.Sec = int64(nsec / 1e9)
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: int32(usec)}
 }
 
 func SetKevent(k *Kevent_t, fd, mode, flags int) {

src/syscall/syscall_netbsd_arm.go

@@ -4,17 +4,12 @@
 
 package syscall
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = int64(nsec / 1e9)
-	ts.Nsec = int32(nsec % 1e9)
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: int32(nsec)}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Usec = int32(nsec % 1e9 / 1e3)
-	tv.Sec = int64(nsec / 1e9)
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: int32(usec)}
 }
 
 func SetKevent(k *Kevent_t, fd, mode, flags int) {

src/syscall/syscall_openbsd_386.go

@@ -4,17 +4,12 @@
 
 package syscall
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = int64(nsec / 1e9)
-	ts.Nsec = int32(nsec % 1e9)
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: int32(nsec)}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Usec = int32(nsec % 1e9 / 1e3)
-	tv.Sec = int64(nsec / 1e9)
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: int32(usec)}
 }
 
 func SetKevent(k *Kevent_t, fd, mode, flags int) {

src/syscall/syscall_openbsd_amd64.go

@@ -4,17 +4,12 @@
 
 package syscall
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = nsec / 1e9
-	ts.Nsec = nsec % 1e9
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: nsec}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Usec = nsec % 1e9 / 1e3
-	tv.Sec = nsec / 1e9
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: usec}
 }
 
 func SetKevent(k *Kevent_t, fd, mode, flags int) {

src/syscall/syscall_openbsd_arm.go

@@ -4,17 +4,12 @@
 
 package syscall
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = int64(nsec / 1e9)
-	ts.Nsec = int32(nsec % 1e9)
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: int32(nsec)}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Usec = int32(nsec % 1e9 / 1e3)
-	tv.Sec = int64(nsec / 1e9)
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: int32(usec)}
 }
 
 func SetKevent(k *Kevent_t, fd, mode, flags int) {

src/syscall/syscall_solaris_amd64.go

@@ -4,17 +4,12 @@
 
 package syscall
 
-func NsecToTimespec(nsec int64) (ts Timespec) {
-	ts.Sec = nsec / 1e9
-	ts.Nsec = nsec % 1e9
-	return
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: nsec}
 }
 
-func NsecToTimeval(nsec int64) (tv Timeval) {
-	nsec += 999 // round up to microsecond
-	tv.Usec = nsec % 1e9 / 1e3
-	tv.Sec = int64(nsec / 1e9)
-	return
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: usec}
 }
 
 func (iov *Iovec) SetLen(length int) {

src/syscall/timestruct.go

@@ -6,6 +6,35 @@
 
 package syscall
 
+// TimespecToNsec converts a Timespec value into a number of
+// nanoseconds since the Unix epoch.
 func TimespecToNsec(ts Timespec) int64 { return int64(ts.Sec)*1e9 + int64(ts.Nsec) }
 
+// NsecToTimespec takes a number of nanoseconds since the Unix epoch
+// and returns the corresponding Timespec value.
+func NsecToTimespec(nsec int64) Timespec {
+	sec := nsec / 1e9
+	nsec = nsec % 1e9
+	if nsec < 0 {
+		nsec += 1e9
+		sec--
+	}
+	return setTimespec(sec, nsec)
+}
+
+// TimevalToNsec converts a Timeval value into a number of nanoseconds
+// since the Unix epoch.
 func TimevalToNsec(tv Timeval) int64 { return int64(tv.Sec)*1e9 + int64(tv.Usec)*1e3 }
+
+// NsecToTimeval takes a number of nanoseconds since the Unix epoch
+// and returns the corresponding Timeval value.
+func NsecToTimeval(nsec int64) Timeval {
+	nsec += 999 // round up to microsecond
+	usec := nsec % 1e9 / 1e3
+	sec := nsec / 1e9
+	if usec < 0 {
+		usec += 1e6
+		sec--
+	}
+	return setTimeval(sec, usec)
+}