return fstatat(fd, path, stat, flags)
}

//sys	Fstatfs(fd int, buf *Statfs_t) (err error)
//sys	Ftruncate(fd int, length int64) (err error)
//sysnb	Getegid() (egid int)
//sysnb	Geteuid() (euid int)
//sysnb	Getgid() (gid int)
//sysnb	getrlimit(resource int, rlim *Rlimit) (err error)
//sysnb	Getuid() (uid int)
//sys	Listen(s int, n int) (err error)

//sys	Fchown(fd int, uid int, gid int) (err error)
//sys	Fstatfs(fd int, buf *Statfs_t) (err error)
//sys	Ftruncate(fd int, length int64) (err error)
//sysnb	Getegid() (egid int)
//sysnb	Geteuid() (euid int)
//sysnb	Getgid() (gid int)
//sysnb	Getrlimit(resource int, rlim *Rlimit) (err error)
//sysnb	Getuid() (uid int)
//sys	Lchown(path string, uid int, gid int) (err error)
//sys	Listen(s int, n int) (err error)

type SysProcAttr struct {
	Chroot     string      // Chroot.
	Credential *Credential // Credential.
	Ptrace     bool        // Enable tracing.
	Setsid     bool        // Create session.
	// Setpgid sets the process group ID of the child to Pgid,
	// or, if Pgid == 0, to the new child's process ID.
	Setpgid bool
	// Setctty sets the controlling terminal of the child to
	// file descriptor Ctty. Ctty must be a descriptor number

	MOVL	$·Baton(SB), BX
	// Rewind stack pointer so anything that happens on the stack
	// will clobber the test pattern created by the caller
	ADDL	$(1024 * 8), SP

	// Ask signaller to setgid
	MOVL	$1, (BX)

	// Wait for setgid completion
loop:
	PAUSE
	MOVL	(BX), AX
	CMPL	AX, $0
	JNE	loop

	// Restore stack
	SUBL	$(1024 * 8), SP

	// Rewind stack pointer so anything that happens on the stack
	// will clobber the test pattern created by the caller
	ADD	$(1024 * 8), R15

	// Ask signaller to setgid
	MOVD	$·Baton(SB), R5
	MOVW	$1, 0(R5)

	// Wait for setgid completion
loop:
	SYNC
	MOVW	·Baton(SB), R3
	CMPBNE	R3, $0, loop

	// Restore stack
	SUB	$(1024 * 8), R15

	Ptrace bool
	Setsid bool // Create session.
	// Setpgid sets the process group ID of the child to Pgid,
	// or, if Pgid == 0, to the new child's process ID.
	Setpgid bool
	// Setctty sets the controlling terminal of the child to
	// file descriptor Ctty. Ctty must be a descriptor number
	// in the child process: an index into ProcAttr.Files.
	// This is only meaningful if Setsid is true.
	Setctty bool

	// Rewind stack pointer so anything that happens on the stack
	// will clobber the test pattern created by the caller
	ADDV	$(1024*8), R3

	// Ask signaller to setgid
	MOVW	$1, R12
	DBAR
	MOVW	R12, ·Baton(SB)
	DBAR

	// Wait for setgid completion
loop:
	DBAR
	MOVW	·Baton(SB), R12
	OR	R13, R13, R13	// hint that we're in a spin loop
	BNE	R12, loop
	DBAR

	// Restore stack
	ADDV	$(-1024*8), R3

type SysProcAttr struct {
	Chroot     string      // Chroot.
	Credential *Credential // Credential.
	Ptrace     bool        // Enable tracing.
	Setsid     bool        // Create session.
	// Setpgid sets the process group ID of the child to Pgid,
	// or, if Pgid == 0, to the new child's process ID.
	Setpgid bool
	// Setctty sets the controlling terminal of the child to
	// file descriptor Ctty. Ctty must be a descriptor number

TEXT ·RewindAndSetgid(SB),NOSPLIT,$0-0
	// Rewind stack pointer so anything that happens on the stack
	// will clobber the test pattern created by the caller
	ADDQ	$(1024 * 8), SP

	// Ask signaller to setgid
	MOVL	$1, ·Baton(SB)

	// Wait for setgid completion
loop:
	PAUSE
	MOVL	·Baton(SB), AX
	CMPL	AX, $0
	JNE	loop

	// Restore stack
	SUBQ	$(1024 * 8), SP

	// will clobber the test pattern created by the caller
	ADD	$(1024 * 8), RSP

	// Ask signaller to setgid
	MOVD	$·Baton(SB), R0
	MOVD	$1, R1
storeloop:
	LDAXRW	(R0), R2
	STLXRW	R1, (R0), R3
	CBNZ	R3, storeloop

	// Wait for setgid completion
	MOVW	$0, R1
	MOVW	$0, R2
loop:
	LDAXRW	(R0), R3
	CMPW	R1, R3
	BNE	loop
	STLXRW	R2, (R0), R3
	CBNZ	R3, loop