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syscall_bsd.go (15665B)


      1 // Copyright 2009 The Go Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style
      3 // license that can be found in the LICENSE file.
      4 
      5 //go:build darwin || dragonfly || freebsd || netbsd || openbsd
      6 // +build darwin dragonfly freebsd netbsd openbsd
      7 
      8 // BSD system call wrappers shared by *BSD based systems
      9 // including OS X (Darwin) and FreeBSD.  Like the other
     10 // syscall_*.go files it is compiled as Go code but also
     11 // used as input to mksyscall which parses the //sys
     12 // lines and generates system call stubs.
     13 
     14 package unix
     15 
     16 import (
     17 	"runtime"
     18 	"syscall"
     19 	"unsafe"
     20 )
     21 
     22 const ImplementsGetwd = true
     23 
     24 func Getwd() (string, error) {
     25 	var buf [PathMax]byte
     26 	_, err := Getcwd(buf[0:])
     27 	if err != nil {
     28 		return "", err
     29 	}
     30 	n := clen(buf[:])
     31 	if n < 1 {
     32 		return "", EINVAL
     33 	}
     34 	return string(buf[:n]), nil
     35 }
     36 
     37 /*
     38  * Wrapped
     39  */
     40 
     41 //sysnb	getgroups(ngid int, gid *_Gid_t) (n int, err error)
     42 //sysnb	setgroups(ngid int, gid *_Gid_t) (err error)
     43 
     44 func Getgroups() (gids []int, err error) {
     45 	n, err := getgroups(0, nil)
     46 	if err != nil {
     47 		return nil, err
     48 	}
     49 	if n == 0 {
     50 		return nil, nil
     51 	}
     52 
     53 	// Sanity check group count. Max is 16 on BSD.
     54 	if n < 0 || n > 1000 {
     55 		return nil, EINVAL
     56 	}
     57 
     58 	a := make([]_Gid_t, n)
     59 	n, err = getgroups(n, &a[0])
     60 	if err != nil {
     61 		return nil, err
     62 	}
     63 	gids = make([]int, n)
     64 	for i, v := range a[0:n] {
     65 		gids[i] = int(v)
     66 	}
     67 	return
     68 }
     69 
     70 func Setgroups(gids []int) (err error) {
     71 	if len(gids) == 0 {
     72 		return setgroups(0, nil)
     73 	}
     74 
     75 	a := make([]_Gid_t, len(gids))
     76 	for i, v := range gids {
     77 		a[i] = _Gid_t(v)
     78 	}
     79 	return setgroups(len(a), &a[0])
     80 }
     81 
     82 // Wait status is 7 bits at bottom, either 0 (exited),
     83 // 0x7F (stopped), or a signal number that caused an exit.
     84 // The 0x80 bit is whether there was a core dump.
     85 // An extra number (exit code, signal causing a stop)
     86 // is in the high bits.
     87 
     88 type WaitStatus uint32
     89 
     90 const (
     91 	mask  = 0x7F
     92 	core  = 0x80
     93 	shift = 8
     94 
     95 	exited  = 0
     96 	killed  = 9
     97 	stopped = 0x7F
     98 )
     99 
    100 func (w WaitStatus) Exited() bool { return w&mask == exited }
    101 
    102 func (w WaitStatus) ExitStatus() int {
    103 	if w&mask != exited {
    104 		return -1
    105 	}
    106 	return int(w >> shift)
    107 }
    108 
    109 func (w WaitStatus) Signaled() bool { return w&mask != stopped && w&mask != 0 }
    110 
    111 func (w WaitStatus) Signal() syscall.Signal {
    112 	sig := syscall.Signal(w & mask)
    113 	if sig == stopped || sig == 0 {
    114 		return -1
    115 	}
    116 	return sig
    117 }
    118 
    119 func (w WaitStatus) CoreDump() bool { return w.Signaled() && w&core != 0 }
    120 
    121 func (w WaitStatus) Stopped() bool { return w&mask == stopped && syscall.Signal(w>>shift) != SIGSTOP }
    122 
    123 func (w WaitStatus) Killed() bool { return w&mask == killed && syscall.Signal(w>>shift) != SIGKILL }
    124 
    125 func (w WaitStatus) Continued() bool { return w&mask == stopped && syscall.Signal(w>>shift) == SIGSTOP }
    126 
    127 func (w WaitStatus) StopSignal() syscall.Signal {
    128 	if !w.Stopped() {
    129 		return -1
    130 	}
    131 	return syscall.Signal(w>>shift) & 0xFF
    132 }
    133 
    134 func (w WaitStatus) TrapCause() int { return -1 }
    135 
    136 //sys	wait4(pid int, wstatus *_C_int, options int, rusage *Rusage) (wpid int, err error)
    137 
    138 func Wait4(pid int, wstatus *WaitStatus, options int, rusage *Rusage) (wpid int, err error) {
    139 	var status _C_int
    140 	wpid, err = wait4(pid, &status, options, rusage)
    141 	if wstatus != nil {
    142 		*wstatus = WaitStatus(status)
    143 	}
    144 	return
    145 }
    146 
    147 //sys	accept(s int, rsa *RawSockaddrAny, addrlen *_Socklen) (fd int, err error)
    148 //sys	bind(s int, addr unsafe.Pointer, addrlen _Socklen) (err error)
    149 //sys	connect(s int, addr unsafe.Pointer, addrlen _Socklen) (err error)
    150 //sysnb	socket(domain int, typ int, proto int) (fd int, err error)
    151 //sys	getsockopt(s int, level int, name int, val unsafe.Pointer, vallen *_Socklen) (err error)
    152 //sys	setsockopt(s int, level int, name int, val unsafe.Pointer, vallen uintptr) (err error)
    153 //sysnb	getpeername(fd int, rsa *RawSockaddrAny, addrlen *_Socklen) (err error)
    154 //sysnb	getsockname(fd int, rsa *RawSockaddrAny, addrlen *_Socklen) (err error)
    155 //sys	Shutdown(s int, how int) (err error)
    156 
    157 func (sa *SockaddrInet4) sockaddr() (unsafe.Pointer, _Socklen, error) {
    158 	if sa.Port < 0 || sa.Port > 0xFFFF {
    159 		return nil, 0, EINVAL
    160 	}
    161 	sa.raw.Len = SizeofSockaddrInet4
    162 	sa.raw.Family = AF_INET
    163 	p := (*[2]byte)(unsafe.Pointer(&sa.raw.Port))
    164 	p[0] = byte(sa.Port >> 8)
    165 	p[1] = byte(sa.Port)
    166 	sa.raw.Addr = sa.Addr
    167 	return unsafe.Pointer(&sa.raw), _Socklen(sa.raw.Len), nil
    168 }
    169 
    170 func (sa *SockaddrInet6) sockaddr() (unsafe.Pointer, _Socklen, error) {
    171 	if sa.Port < 0 || sa.Port > 0xFFFF {
    172 		return nil, 0, EINVAL
    173 	}
    174 	sa.raw.Len = SizeofSockaddrInet6
    175 	sa.raw.Family = AF_INET6
    176 	p := (*[2]byte)(unsafe.Pointer(&sa.raw.Port))
    177 	p[0] = byte(sa.Port >> 8)
    178 	p[1] = byte(sa.Port)
    179 	sa.raw.Scope_id = sa.ZoneId
    180 	sa.raw.Addr = sa.Addr
    181 	return unsafe.Pointer(&sa.raw), _Socklen(sa.raw.Len), nil
    182 }
    183 
    184 func (sa *SockaddrUnix) sockaddr() (unsafe.Pointer, _Socklen, error) {
    185 	name := sa.Name
    186 	n := len(name)
    187 	if n >= len(sa.raw.Path) || n == 0 {
    188 		return nil, 0, EINVAL
    189 	}
    190 	sa.raw.Len = byte(3 + n) // 2 for Family, Len; 1 for NUL
    191 	sa.raw.Family = AF_UNIX
    192 	for i := 0; i < n; i++ {
    193 		sa.raw.Path[i] = int8(name[i])
    194 	}
    195 	return unsafe.Pointer(&sa.raw), _Socklen(sa.raw.Len), nil
    196 }
    197 
    198 func (sa *SockaddrDatalink) sockaddr() (unsafe.Pointer, _Socklen, error) {
    199 	if sa.Index == 0 {
    200 		return nil, 0, EINVAL
    201 	}
    202 	sa.raw.Len = sa.Len
    203 	sa.raw.Family = AF_LINK
    204 	sa.raw.Index = sa.Index
    205 	sa.raw.Type = sa.Type
    206 	sa.raw.Nlen = sa.Nlen
    207 	sa.raw.Alen = sa.Alen
    208 	sa.raw.Slen = sa.Slen
    209 	sa.raw.Data = sa.Data
    210 	return unsafe.Pointer(&sa.raw), SizeofSockaddrDatalink, nil
    211 }
    212 
    213 func anyToSockaddr(fd int, rsa *RawSockaddrAny) (Sockaddr, error) {
    214 	switch rsa.Addr.Family {
    215 	case AF_LINK:
    216 		pp := (*RawSockaddrDatalink)(unsafe.Pointer(rsa))
    217 		sa := new(SockaddrDatalink)
    218 		sa.Len = pp.Len
    219 		sa.Family = pp.Family
    220 		sa.Index = pp.Index
    221 		sa.Type = pp.Type
    222 		sa.Nlen = pp.Nlen
    223 		sa.Alen = pp.Alen
    224 		sa.Slen = pp.Slen
    225 		sa.Data = pp.Data
    226 		return sa, nil
    227 
    228 	case AF_UNIX:
    229 		pp := (*RawSockaddrUnix)(unsafe.Pointer(rsa))
    230 		if pp.Len < 2 || pp.Len > SizeofSockaddrUnix {
    231 			return nil, EINVAL
    232 		}
    233 		sa := new(SockaddrUnix)
    234 
    235 		// Some BSDs include the trailing NUL in the length, whereas
    236 		// others do not. Work around this by subtracting the leading
    237 		// family and len. The path is then scanned to see if a NUL
    238 		// terminator still exists within the length.
    239 		n := int(pp.Len) - 2 // subtract leading Family, Len
    240 		for i := 0; i < n; i++ {
    241 			if pp.Path[i] == 0 {
    242 				// found early NUL; assume Len included the NUL
    243 				// or was overestimating.
    244 				n = i
    245 				break
    246 			}
    247 		}
    248 		sa.Name = string(unsafe.Slice((*byte)(unsafe.Pointer(&pp.Path[0])), n))
    249 		return sa, nil
    250 
    251 	case AF_INET:
    252 		pp := (*RawSockaddrInet4)(unsafe.Pointer(rsa))
    253 		sa := new(SockaddrInet4)
    254 		p := (*[2]byte)(unsafe.Pointer(&pp.Port))
    255 		sa.Port = int(p[0])<<8 + int(p[1])
    256 		sa.Addr = pp.Addr
    257 		return sa, nil
    258 
    259 	case AF_INET6:
    260 		pp := (*RawSockaddrInet6)(unsafe.Pointer(rsa))
    261 		sa := new(SockaddrInet6)
    262 		p := (*[2]byte)(unsafe.Pointer(&pp.Port))
    263 		sa.Port = int(p[0])<<8 + int(p[1])
    264 		sa.ZoneId = pp.Scope_id
    265 		sa.Addr = pp.Addr
    266 		return sa, nil
    267 	}
    268 	return anyToSockaddrGOOS(fd, rsa)
    269 }
    270 
    271 func Accept(fd int) (nfd int, sa Sockaddr, err error) {
    272 	var rsa RawSockaddrAny
    273 	var len _Socklen = SizeofSockaddrAny
    274 	nfd, err = accept(fd, &rsa, &len)
    275 	if err != nil {
    276 		return
    277 	}
    278 	if (runtime.GOOS == "darwin" || runtime.GOOS == "ios") && len == 0 {
    279 		// Accepted socket has no address.
    280 		// This is likely due to a bug in xnu kernels,
    281 		// where instead of ECONNABORTED error socket
    282 		// is accepted, but has no address.
    283 		Close(nfd)
    284 		return 0, nil, ECONNABORTED
    285 	}
    286 	sa, err = anyToSockaddr(fd, &rsa)
    287 	if err != nil {
    288 		Close(nfd)
    289 		nfd = 0
    290 	}
    291 	return
    292 }
    293 
    294 func Getsockname(fd int) (sa Sockaddr, err error) {
    295 	var rsa RawSockaddrAny
    296 	var len _Socklen = SizeofSockaddrAny
    297 	if err = getsockname(fd, &rsa, &len); err != nil {
    298 		return
    299 	}
    300 	// TODO(jsing): DragonFly has a "bug" (see issue 3349), which should be
    301 	// reported upstream.
    302 	if runtime.GOOS == "dragonfly" && rsa.Addr.Family == AF_UNSPEC && rsa.Addr.Len == 0 {
    303 		rsa.Addr.Family = AF_UNIX
    304 		rsa.Addr.Len = SizeofSockaddrUnix
    305 	}
    306 	return anyToSockaddr(fd, &rsa)
    307 }
    308 
    309 //sysnb	socketpair(domain int, typ int, proto int, fd *[2]int32) (err error)
    310 
    311 // GetsockoptString returns the string value of the socket option opt for the
    312 // socket associated with fd at the given socket level.
    313 func GetsockoptString(fd, level, opt int) (string, error) {
    314 	buf := make([]byte, 256)
    315 	vallen := _Socklen(len(buf))
    316 	err := getsockopt(fd, level, opt, unsafe.Pointer(&buf[0]), &vallen)
    317 	if err != nil {
    318 		return "", err
    319 	}
    320 	return string(buf[:vallen-1]), nil
    321 }
    322 
    323 //sys	recvfrom(fd int, p []byte, flags int, from *RawSockaddrAny, fromlen *_Socklen) (n int, err error)
    324 //sys	sendto(s int, buf []byte, flags int, to unsafe.Pointer, addrlen _Socklen) (err error)
    325 //sys	recvmsg(s int, msg *Msghdr, flags int) (n int, err error)
    326 
    327 func recvmsgRaw(fd int, iov []Iovec, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn int, recvflags int, err error) {
    328 	var msg Msghdr
    329 	msg.Name = (*byte)(unsafe.Pointer(rsa))
    330 	msg.Namelen = uint32(SizeofSockaddrAny)
    331 	var dummy byte
    332 	if len(oob) > 0 {
    333 		// receive at least one normal byte
    334 		if emptyIovecs(iov) {
    335 			var iova [1]Iovec
    336 			iova[0].Base = &dummy
    337 			iova[0].SetLen(1)
    338 			iov = iova[:]
    339 		}
    340 		msg.Control = (*byte)(unsafe.Pointer(&oob[0]))
    341 		msg.SetControllen(len(oob))
    342 	}
    343 	if len(iov) > 0 {
    344 		msg.Iov = &iov[0]
    345 		msg.SetIovlen(len(iov))
    346 	}
    347 	if n, err = recvmsg(fd, &msg, flags); err != nil {
    348 		return
    349 	}
    350 	oobn = int(msg.Controllen)
    351 	recvflags = int(msg.Flags)
    352 	return
    353 }
    354 
    355 //sys	sendmsg(s int, msg *Msghdr, flags int) (n int, err error)
    356 
    357 func sendmsgN(fd int, iov []Iovec, oob []byte, ptr unsafe.Pointer, salen _Socklen, flags int) (n int, err error) {
    358 	var msg Msghdr
    359 	msg.Name = (*byte)(unsafe.Pointer(ptr))
    360 	msg.Namelen = uint32(salen)
    361 	var dummy byte
    362 	var empty bool
    363 	if len(oob) > 0 {
    364 		// send at least one normal byte
    365 		empty = emptyIovecs(iov)
    366 		if empty {
    367 			var iova [1]Iovec
    368 			iova[0].Base = &dummy
    369 			iova[0].SetLen(1)
    370 			iov = iova[:]
    371 		}
    372 		msg.Control = (*byte)(unsafe.Pointer(&oob[0]))
    373 		msg.SetControllen(len(oob))
    374 	}
    375 	if len(iov) > 0 {
    376 		msg.Iov = &iov[0]
    377 		msg.SetIovlen(len(iov))
    378 	}
    379 	if n, err = sendmsg(fd, &msg, flags); err != nil {
    380 		return 0, err
    381 	}
    382 	if len(oob) > 0 && empty {
    383 		n = 0
    384 	}
    385 	return n, nil
    386 }
    387 
    388 //sys	kevent(kq int, change unsafe.Pointer, nchange int, event unsafe.Pointer, nevent int, timeout *Timespec) (n int, err error)
    389 
    390 func Kevent(kq int, changes, events []Kevent_t, timeout *Timespec) (n int, err error) {
    391 	var change, event unsafe.Pointer
    392 	if len(changes) > 0 {
    393 		change = unsafe.Pointer(&changes[0])
    394 	}
    395 	if len(events) > 0 {
    396 		event = unsafe.Pointer(&events[0])
    397 	}
    398 	return kevent(kq, change, len(changes), event, len(events), timeout)
    399 }
    400 
    401 // sysctlmib translates name to mib number and appends any additional args.
    402 func sysctlmib(name string, args ...int) ([]_C_int, error) {
    403 	// Translate name to mib number.
    404 	mib, err := nametomib(name)
    405 	if err != nil {
    406 		return nil, err
    407 	}
    408 
    409 	for _, a := range args {
    410 		mib = append(mib, _C_int(a))
    411 	}
    412 
    413 	return mib, nil
    414 }
    415 
    416 func Sysctl(name string) (string, error) {
    417 	return SysctlArgs(name)
    418 }
    419 
    420 func SysctlArgs(name string, args ...int) (string, error) {
    421 	buf, err := SysctlRaw(name, args...)
    422 	if err != nil {
    423 		return "", err
    424 	}
    425 	n := len(buf)
    426 
    427 	// Throw away terminating NUL.
    428 	if n > 0 && buf[n-1] == '\x00' {
    429 		n--
    430 	}
    431 	return string(buf[0:n]), nil
    432 }
    433 
    434 func SysctlUint32(name string) (uint32, error) {
    435 	return SysctlUint32Args(name)
    436 }
    437 
    438 func SysctlUint32Args(name string, args ...int) (uint32, error) {
    439 	mib, err := sysctlmib(name, args...)
    440 	if err != nil {
    441 		return 0, err
    442 	}
    443 
    444 	n := uintptr(4)
    445 	buf := make([]byte, 4)
    446 	if err := sysctl(mib, &buf[0], &n, nil, 0); err != nil {
    447 		return 0, err
    448 	}
    449 	if n != 4 {
    450 		return 0, EIO
    451 	}
    452 	return *(*uint32)(unsafe.Pointer(&buf[0])), nil
    453 }
    454 
    455 func SysctlUint64(name string, args ...int) (uint64, error) {
    456 	mib, err := sysctlmib(name, args...)
    457 	if err != nil {
    458 		return 0, err
    459 	}
    460 
    461 	n := uintptr(8)
    462 	buf := make([]byte, 8)
    463 	if err := sysctl(mib, &buf[0], &n, nil, 0); err != nil {
    464 		return 0, err
    465 	}
    466 	if n != 8 {
    467 		return 0, EIO
    468 	}
    469 	return *(*uint64)(unsafe.Pointer(&buf[0])), nil
    470 }
    471 
    472 func SysctlRaw(name string, args ...int) ([]byte, error) {
    473 	mib, err := sysctlmib(name, args...)
    474 	if err != nil {
    475 		return nil, err
    476 	}
    477 
    478 	// Find size.
    479 	n := uintptr(0)
    480 	if err := sysctl(mib, nil, &n, nil, 0); err != nil {
    481 		return nil, err
    482 	}
    483 	if n == 0 {
    484 		return nil, nil
    485 	}
    486 
    487 	// Read into buffer of that size.
    488 	buf := make([]byte, n)
    489 	if err := sysctl(mib, &buf[0], &n, nil, 0); err != nil {
    490 		return nil, err
    491 	}
    492 
    493 	// The actual call may return less than the original reported required
    494 	// size so ensure we deal with that.
    495 	return buf[:n], nil
    496 }
    497 
    498 func SysctlClockinfo(name string) (*Clockinfo, error) {
    499 	mib, err := sysctlmib(name)
    500 	if err != nil {
    501 		return nil, err
    502 	}
    503 
    504 	n := uintptr(SizeofClockinfo)
    505 	var ci Clockinfo
    506 	if err := sysctl(mib, (*byte)(unsafe.Pointer(&ci)), &n, nil, 0); err != nil {
    507 		return nil, err
    508 	}
    509 	if n != SizeofClockinfo {
    510 		return nil, EIO
    511 	}
    512 	return &ci, nil
    513 }
    514 
    515 func SysctlTimeval(name string) (*Timeval, error) {
    516 	mib, err := sysctlmib(name)
    517 	if err != nil {
    518 		return nil, err
    519 	}
    520 
    521 	var tv Timeval
    522 	n := uintptr(unsafe.Sizeof(tv))
    523 	if err := sysctl(mib, (*byte)(unsafe.Pointer(&tv)), &n, nil, 0); err != nil {
    524 		return nil, err
    525 	}
    526 	if n != unsafe.Sizeof(tv) {
    527 		return nil, EIO
    528 	}
    529 	return &tv, nil
    530 }
    531 
    532 //sys	utimes(path string, timeval *[2]Timeval) (err error)
    533 
    534 func Utimes(path string, tv []Timeval) error {
    535 	if tv == nil {
    536 		return utimes(path, nil)
    537 	}
    538 	if len(tv) != 2 {
    539 		return EINVAL
    540 	}
    541 	return utimes(path, (*[2]Timeval)(unsafe.Pointer(&tv[0])))
    542 }
    543 
    544 func UtimesNano(path string, ts []Timespec) error {
    545 	if ts == nil {
    546 		err := utimensat(AT_FDCWD, path, nil, 0)
    547 		if err != ENOSYS {
    548 			return err
    549 		}
    550 		return utimes(path, nil)
    551 	}
    552 	if len(ts) != 2 {
    553 		return EINVAL
    554 	}
    555 	err := utimensat(AT_FDCWD, path, (*[2]Timespec)(unsafe.Pointer(&ts[0])), 0)
    556 	if err != ENOSYS {
    557 		return err
    558 	}
    559 	// Not as efficient as it could be because Timespec and
    560 	// Timeval have different types in the different OSes
    561 	tv := [2]Timeval{
    562 		NsecToTimeval(TimespecToNsec(ts[0])),
    563 		NsecToTimeval(TimespecToNsec(ts[1])),
    564 	}
    565 	return utimes(path, (*[2]Timeval)(unsafe.Pointer(&tv[0])))
    566 }
    567 
    568 func UtimesNanoAt(dirfd int, path string, ts []Timespec, flags int) error {
    569 	if ts == nil {
    570 		return utimensat(dirfd, path, nil, flags)
    571 	}
    572 	if len(ts) != 2 {
    573 		return EINVAL
    574 	}
    575 	return utimensat(dirfd, path, (*[2]Timespec)(unsafe.Pointer(&ts[0])), flags)
    576 }
    577 
    578 //sys	futimes(fd int, timeval *[2]Timeval) (err error)
    579 
    580 func Futimes(fd int, tv []Timeval) error {
    581 	if tv == nil {
    582 		return futimes(fd, nil)
    583 	}
    584 	if len(tv) != 2 {
    585 		return EINVAL
    586 	}
    587 	return futimes(fd, (*[2]Timeval)(unsafe.Pointer(&tv[0])))
    588 }
    589 
    590 //sys	poll(fds *PollFd, nfds int, timeout int) (n int, err error)
    591 
    592 func Poll(fds []PollFd, timeout int) (n int, err error) {
    593 	if len(fds) == 0 {
    594 		return poll(nil, 0, timeout)
    595 	}
    596 	return poll(&fds[0], len(fds), timeout)
    597 }
    598 
    599 // TODO: wrap
    600 //	Acct(name nil-string) (err error)
    601 //	Gethostuuid(uuid *byte, timeout *Timespec) (err error)
    602 //	Ptrace(req int, pid int, addr uintptr, data int) (ret uintptr, err error)
    603 
    604 var mapper = &mmapper{
    605 	active: make(map[*byte][]byte),
    606 	mmap:   mmap,
    607 	munmap: munmap,
    608 }
    609 
    610 func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
    611 	return mapper.Mmap(fd, offset, length, prot, flags)
    612 }
    613 
    614 func Munmap(b []byte) (err error) {
    615 	return mapper.Munmap(b)
    616 }
    617 
    618 //sys	Madvise(b []byte, behav int) (err error)
    619 //sys	Mlock(b []byte) (err error)
    620 //sys	Mlockall(flags int) (err error)
    621 //sys	Mprotect(b []byte, prot int) (err error)
    622 //sys	Msync(b []byte, flags int) (err error)
    623 //sys	Munlock(b []byte) (err error)
    624 //sys	Munlockall() (err error)