KeepAlive(addr) // Just for consistency. Hopefully addr is not a Go address.
}
func madvise_trampoline()

//go:nosplit
//go:cgo_unsafe_args
func open(name *byte, mode, perm int32) (ret int32) {
	ret = libcCall(unsafe.Pointer(abi.FuncPCABI0(open_trampoline)), unsafe.Pointer(&name))
	KeepAlive(name)
	return
}
func open_trampoline()

//go:nosplit
//go:cgo_unsafe_args

	// Set file permission bits.
	mode = fs.FileMode(fi.h.Mode).Perm()

	// Set setuid, setgid and sticky bits.
	if fi.h.Mode&c_ISUID != 0 {
		mode |= fs.ModeSetuid
	}
	if fi.h.Mode&c_ISGID != 0 {
		mode |= fs.ModeSetgid
	}
	if fi.h.Mode&c_ISVTX != 0 {
		mode |= fs.ModeSticky
	}

	// Set file mode bits; clear perm, setuid, setgid, and sticky bits.
	switch m := fs.FileMode(fi.h.Mode) &^ 07777; m {

		if s != "" {
			return s
		}
	}
	return "errno " + itoa.Itoa(int(e))
}

func (e Errno) Is(target error) bool {
	switch target {
	case oserror.ErrPermission:
		return e == EACCES || e == EPERM
	case oserror.ErrExist:
		return e == EEXIST || e == ENOTEMPTY
	case oserror.ErrNotExist:
		return e == ENOENT
	case errors.ErrUnsupported:
		return e == ENOSYS
	}
	return false
}

type SysvIpcPerm struct {
	Key  int32
	Uid  uint32
	Gid  uint32
	Cuid uint32
	Cgid uint32
	Mode uint32
	Seq  uint32
	_    uint32
	_    uint64
	_    uint64
}
type SysvShmDesc struct {
	Perm       SysvIpcPerm
	Atime_high uint32
	Atime      uint32
	Dtime_high uint32
	Dtime      uint32
	Ctime_high uint32
	Ctime      uint32
	_          uint32
	Segsz      uint32
	Cpid       int32

type SysvIpcPerm struct {
	Key  int32
	Uid  uint32
	Gid  uint32
	Cuid uint32
	Cgid uint32
	Mode uint32
	Seq  uint32
	_    uint32
	_    uint64
	_    uint64
}
type SysvShmDesc struct {
	Perm   SysvIpcPerm
	Atime  int64
	Dtime  int64
	Ctime  int64
	Segsz  uint64
	Cpid   int32
	Lpid   int32
	Nattch uint64
	_      uint64
	_      uint64

	Key  int32
	Uid  uint32
	Gid  uint32
	Cuid uint32
	Cgid uint32
	Mode uint32
	_    [0]uint8
	Seq  uint16
	_    uint16
	_    uint64
	_    uint64
}
type SysvShmDesc struct {
	Perm   SysvIpcPerm
	Segsz  uint64
	Atime  int64
	Dtime  int64
	Ctime  int64
	Cpid   int32
	Lpid   int32
	Nattch uint64
	_      uint64
	_      uint64
}

type RISCVHWProbePairs struct {

	Key  int32
	Uid  uint32
	Gid  uint32
	Cuid uint32
	Cgid uint32
	Mode uint16
	_    [2]uint8
	Seq  uint16
	_    uint16
	_    uint32
	_    uint32
}
type SysvShmDesc struct {
	Perm       SysvIpcPerm
	Segsz      uint32
	Atime      uint32
	Atime_high uint32
	Dtime      uint32
	Dtime_high uint32
	Ctime      uint32
	Ctime_high uint32
	Cpid       int32
	Lpid       int32

	Key  int32
	Uid  uint32
	Gid  uint32
	Cuid uint32
	Cgid uint32
	Mode uint32
	_    [0]uint8
	Seq  uint16
	_    uint16
	_    uint64
	_    uint64
}
type SysvShmDesc struct {
	Perm   SysvIpcPerm
	Segsz  uint64
	Atime  int64
	Dtime  int64
	Ctime  int64
	Cpid   int32
	Lpid   int32
	Nattch uint64
	_      uint64
	_      uint64

	n, err = f.pfd.Pwrite(b, off)
	runtime.KeepAlive(f)
	return n, err
}

// syscallMode returns the syscall-specific mode bits from Go's portable mode bits.
func syscallMode(i FileMode) (o uint32) {
	o |= uint32(i.Perm())
	if i&ModeSetuid != 0 {
		o |= syscall.S_ISUID
	}
	if i&ModeSetgid != 0 {
		o |= syscall.S_ISGID
	}
	if i&ModeSticky != 0 {
		o |= syscall.S_ISVTX
	}
	// No mapping for Go's ModeTemporary (plan9 only).

// KeyctlSetperm implements the KEYCTL_SETPERM command. The perm value is the
// key handle permission mask as described in the "keyctl setperm" section of
// http://man7.org/linux/man-pages/man1/keyctl.1.html.
// See the full documentation at:
// http://man7.org/linux/man-pages/man3/keyctl_setperm.3.html
func KeyctlSetperm(id int, perm uint32) error {
	_, err := KeyctlInt(KEYCTL_SETPERM, id, int(perm), 0, 0)
	return err
}