syscall: add utimensat libc wrapper on darwin

Add utimensat as a wrapper around the libc function of the same name.
utimensat was added in macOS 10.13 which is the minimum supported
release since Go 1.17 dropped support for macOS 10.12.

This also allows to drop the fallback to setattrlistTimes which was
used to set timestamps with nanosecond resolution before utimensat could
be used, see #22528 and CL 74952.

Updates #22528

Change-Id: I87b6a76acf1d642ceede9254f7d9d06dddc3fd71
Reviewed-on: https://go-review.googlesource.com/c/go/+/358274
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/src/syscall/syscall_bsd.go b/src/syscall/syscall_bsd.go
index 595e705..40b1c07 100644
--- a/src/syscall/syscall_bsd.go
+++ b/src/syscall/syscall_bsd.go
@@ -524,12 +524,7 @@
 	if len(ts) != 2 {
 		return EINVAL
 	}
-	// Darwin setattrlist can set nanosecond timestamps
-	err := setattrlistTimes(path, ts)
-	if err != ENOSYS {
-		return err
-	}
-	err = utimensat(_AT_FDCWD, path, (*[2]Timespec)(unsafe.Pointer(&ts[0])), 0)
+	err := utimensat(_AT_FDCWD, path, (*[2]Timespec)(unsafe.Pointer(&ts[0])), 0)
 	if err != ENOSYS {
 		return err
 	}
diff --git a/src/syscall/syscall_darwin.go b/src/syscall/syscall_darwin.go
index a4fe4f1..5bb34e3 100644
--- a/src/syscall/syscall_darwin.go
+++ b/src/syscall/syscall_darwin.go
@@ -72,22 +72,6 @@
 func PtraceAttach(pid int) (err error) { return ptrace(PT_ATTACH, pid, 0, 0) }
 func PtraceDetach(pid int) (err error) { return ptrace(PT_DETACH, pid, 0, 0) }
 
-const (
-	attrBitMapCount = 5
-	attrCmnModtime  = 0x00000400
-	attrCmnAcctime  = 0x00001000
-)
-
-type attrList struct {
-	bitmapCount uint16
-	_           uint16
-	CommonAttr  uint32
-	VolAttr     uint32
-	DirAttr     uint32
-	FileAttr    uint32
-	Forkattr    uint32
-}
-
 //sysnb pipe(p *[2]int32) (err error)
 
 func Pipe(p []int) (err error) {
@@ -120,42 +104,7 @@
 
 //go:cgo_import_dynamic libc_getfsstat getfsstat "/usr/lib/libSystem.B.dylib"
 
-func setattrlistTimes(path string, times []Timespec) error {
-	_p0, err := BytePtrFromString(path)
-	if err != nil {
-		return err
-	}
-
-	var attrList attrList
-	attrList.bitmapCount = attrBitMapCount
-	attrList.CommonAttr = attrCmnModtime | attrCmnAcctime
-
-	// order is mtime, atime: the opposite of Chtimes
-	attributes := [2]Timespec{times[1], times[0]}
-	const options = 0
-	_, _, e1 := syscall6(
-		abi.FuncPCABI0(libc_setattrlist_trampoline),
-		uintptr(unsafe.Pointer(_p0)),
-		uintptr(unsafe.Pointer(&attrList)),
-		uintptr(unsafe.Pointer(&attributes)),
-		uintptr(unsafe.Sizeof(attributes)),
-		uintptr(options),
-		0,
-	)
-	if e1 != 0 {
-		return e1
-	}
-	return nil
-}
-
-func libc_setattrlist_trampoline()
-
-//go:cgo_import_dynamic libc_setattrlist setattrlist "/usr/lib/libSystem.B.dylib"
-
-func utimensat(dirfd int, path string, times *[2]Timespec, flag int) error {
-	// Darwin doesn't support SYS_UTIMENSAT
-	return ENOSYS
-}
+//sys	utimensat(dirfd int, path string, times *[2]Timespec, flags int) (err error)
 
 /*
  * Wrapped
diff --git a/src/syscall/syscall_dragonfly.go b/src/syscall/syscall_dragonfly.go
index b01a4ad..16adf30 100644
--- a/src/syscall/syscall_dragonfly.go
+++ b/src/syscall/syscall_dragonfly.go
@@ -156,11 +156,6 @@
 	return
 }
 
-func setattrlistTimes(path string, times []Timespec) error {
-	// used on Darwin for UtimesNano
-	return ENOSYS
-}
-
 /*
  * Exposed directly
  */
diff --git a/src/syscall/syscall_freebsd.go b/src/syscall/syscall_freebsd.go
index 7c7b89a..6f44b25 100644
--- a/src/syscall/syscall_freebsd.go
+++ b/src/syscall/syscall_freebsd.go
@@ -176,11 +176,6 @@
 	return
 }
 
-func setattrlistTimes(path string, times []Timespec) error {
-	// used on Darwin for UtimesNano
-	return ENOSYS
-}
-
 func Stat(path string, st *Stat_t) (err error) {
 	var oldStat stat_freebsd11_t
 	if supportsABI(_ino64First) {
diff --git a/src/syscall/syscall_netbsd.go b/src/syscall/syscall_netbsd.go
index fc13b70..6f05b0d 100644
--- a/src/syscall/syscall_netbsd.go
+++ b/src/syscall/syscall_netbsd.go
@@ -146,11 +146,6 @@
 	return -1, ENOSYS
 }
 
-func setattrlistTimes(path string, times []Timespec) error {
-	// used on Darwin for UtimesNano
-	return ENOSYS
-}
-
 /*
  * Exposed directly
  */
diff --git a/src/syscall/syscall_openbsd.go b/src/syscall/syscall_openbsd.go
index 5a5ba5a..195cf86 100644
--- a/src/syscall/syscall_openbsd.go
+++ b/src/syscall/syscall_openbsd.go
@@ -121,11 +121,6 @@
 	return
 }
 
-func setattrlistTimes(path string, times []Timespec) error {
-	// used on Darwin for UtimesNano
-	return ENOSYS
-}
-
 /*
  * Exposed directly
  */
diff --git a/src/syscall/zsyscall_darwin_amd64.go b/src/syscall/zsyscall_darwin_amd64.go
index 07a519d..ff88fef 100644
--- a/src/syscall/zsyscall_darwin_amd64.go
+++ b/src/syscall/zsyscall_darwin_amd64.go
@@ -345,6 +345,25 @@
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func utimensat(dirfd int, path string, times *[2]Timespec, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := syscall6(abi.FuncPCABI0(libc_utimensat_trampoline), uintptr(dirfd), uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(times)), uintptr(flags), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_utimensat_trampoline()
+
+//go:cgo_import_dynamic libc_utimensat utimensat "/usr/lib/libSystem.B.dylib"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func kill(pid int, signum int, posix int) (err error) {
 	_, _, e1 := syscall(abi.FuncPCABI0(libc_kill_trampoline), uintptr(pid), uintptr(signum), uintptr(posix))
 	if e1 != 0 {
diff --git a/src/syscall/zsyscall_darwin_amd64.s b/src/syscall/zsyscall_darwin_amd64.s
index 492f947..563083d 100644
--- a/src/syscall/zsyscall_darwin_amd64.s
+++ b/src/syscall/zsyscall_darwin_amd64.s
@@ -3,8 +3,6 @@
 #include "textflag.h"
 TEXT ·libc_getfsstat_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_getfsstat(SB)
-TEXT ·libc_setattrlist_trampoline(SB),NOSPLIT,$0-0
-	JMP	libc_setattrlist(SB)
 TEXT ·libc_fdopendir_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_fdopendir(SB)
 TEXT ·libc_sendfile_trampoline(SB),NOSPLIT,$0-0
@@ -53,6 +51,8 @@
 	JMP	libc_fcntl(SB)
 TEXT ·libc_pipe_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_pipe(SB)
+TEXT ·libc_utimensat_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_utimensat(SB)
 TEXT ·libc_kill_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_kill(SB)
 TEXT ·libc_access_trampoline(SB),NOSPLIT,$0-0
diff --git a/src/syscall/zsyscall_darwin_arm64.go b/src/syscall/zsyscall_darwin_arm64.go
index 5ae0967..b096b5e 100644
--- a/src/syscall/zsyscall_darwin_arm64.go
+++ b/src/syscall/zsyscall_darwin_arm64.go
@@ -345,6 +345,25 @@
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func utimensat(dirfd int, path string, times *[2]Timespec, flags int) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	_, _, e1 := syscall6(abi.FuncPCABI0(libc_utimensat_trampoline), uintptr(dirfd), uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(times)), uintptr(flags), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_utimensat_trampoline()
+
+//go:cgo_import_dynamic libc_utimensat utimensat "/usr/lib/libSystem.B.dylib"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func kill(pid int, signum int, posix int) (err error) {
 	_, _, e1 := syscall(abi.FuncPCABI0(libc_kill_trampoline), uintptr(pid), uintptr(signum), uintptr(posix))
 	if e1 != 0 {
diff --git a/src/syscall/zsyscall_darwin_arm64.s b/src/syscall/zsyscall_darwin_arm64.s
index b606c6e..0567a42 100644
--- a/src/syscall/zsyscall_darwin_arm64.s
+++ b/src/syscall/zsyscall_darwin_arm64.s
@@ -3,8 +3,6 @@
 #include "textflag.h"
 TEXT ·libc_getfsstat_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_getfsstat(SB)
-TEXT ·libc_setattrlist_trampoline(SB),NOSPLIT,$0-0
-	JMP	libc_setattrlist(SB)
 TEXT ·libc_fdopendir_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_fdopendir(SB)
 TEXT ·libc_sendfile_trampoline(SB),NOSPLIT,$0-0
@@ -53,6 +51,8 @@
 	JMP	libc_fcntl(SB)
 TEXT ·libc_pipe_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_pipe(SB)
+TEXT ·libc_utimensat_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_utimensat(SB)
 TEXT ·libc_kill_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_kill(SB)
 TEXT ·libc_access_trampoline(SB),NOSPLIT,$0-0