unix: add Readlinkat on openbsd

Change-Id: I1069c327a5ce01ca2bfa37a889d3c6fd72b7859d
Reviewed-on: https://go-review.googlesource.com/c/145517
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

unix/syscall_openbsd.go

@@ -272,6 +272,7 @@ func Uname(uname *Utsname) error {
 //sys	Pwrite(fd int, p []byte, offset int64) (n int, err error)
 //sys	read(fd int, p []byte) (n int, err error)
 //sys	Readlink(path string, buf []byte) (n int, err error)
+//sys	Readlinkat(dirfd int, path string, buf []byte) (n int, err error)
 //sys	Rename(from string, to string) (err error)
 //sys	Revoke(path string) (err error)
 //sys	Rmdir(path string) (err error)
@@ -361,7 +362,6 @@ func Uname(uname *Utsname) error {
 // profil
 // pwritev
 // quotactl
-// readlinkat
 // readv
 // reboot
 // renameat

unix/zsyscall_openbsd_386.go

@@ -1121,6 +1121,28 @@ func Readlink(path string, buf []byte) (n int, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func Readlinkat(dirfd int, path string, buf []byte) (n int, err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	var _p1 unsafe.Pointer
+	if len(buf) > 0 {
+		_p1 = unsafe.Pointer(&buf[0])
+	} else {
+		_p1 = unsafe.Pointer(&_zero)
+	}
+	r0, _, e1 := Syscall6(SYS_READLINKAT, uintptr(dirfd), uintptr(unsafe.Pointer(_p0)), uintptr(_p1), uintptr(len(buf)), 0, 0)
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Rename(from string, to string) (err error) {
 	var _p0 *byte
 	_p0, err = BytePtrFromString(from)

unix/zsyscall_openbsd_amd64.go

@@ -1121,6 +1121,28 @@ func Readlink(path string, buf []byte) (n int, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func Readlinkat(dirfd int, path string, buf []byte) (n int, err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	var _p1 unsafe.Pointer
+	if len(buf) > 0 {
+		_p1 = unsafe.Pointer(&buf[0])
+	} else {
+		_p1 = unsafe.Pointer(&_zero)
+	}
+	r0, _, e1 := Syscall6(SYS_READLINKAT, uintptr(dirfd), uintptr(unsafe.Pointer(_p0)), uintptr(_p1), uintptr(len(buf)), 0, 0)
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Rename(from string, to string) (err error) {
 	var _p0 *byte
 	_p0, err = BytePtrFromString(from)

unix/zsyscall_openbsd_arm.go

@@ -1121,6 +1121,28 @@ func Readlink(path string, buf []byte) (n int, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func Readlinkat(dirfd int, path string, buf []byte) (n int, err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(path)
+	if err != nil {
+		return
+	}
+	var _p1 unsafe.Pointer
+	if len(buf) > 0 {
+		_p1 = unsafe.Pointer(&buf[0])
+	} else {
+		_p1 = unsafe.Pointer(&_zero)
+	}
+	r0, _, e1 := Syscall6(SYS_READLINKAT, uintptr(dirfd), uintptr(unsafe.Pointer(_p0)), uintptr(_p1), uintptr(len(buf)), 0, 0)
+	n = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Rename(from string, to string) (err error) {
 	var _p0 *byte
 	_p0, err = BytePtrFromString(from)