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      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 // +build darwin dragonfly freebsd netbsd openbsd
      6 
      7 // BSD system call wrappers shared by *BSD based systems
      8 // including OS X (Darwin) and FreeBSD.  Like the other
      9 // syscall_*.go files it is compiled as Go code but also
     10 // used as input to mksyscall which parses the //sys
     11 // lines and generates system call stubs.
     12 
     13 package syscall
     14 
     15 import (
     16 	"runtime"
     17 	"unsafe"
     18 )
     19 
     20 /*
     21  * Wrapped
     22  */
     23 
     24 //sysnb	getgroups(ngid int, gid *_Gid_t) (n int, err error)
     25 //sysnb	setgroups(ngid int, gid *_Gid_t) (err error)
     26 
     27 func Getgroups() (gids []int, err error) {
     28 	n, err := getgroups(0, nil)
     29 	if err != nil {
     30 		return nil, err
     31 	}
     32 	if n == 0 {
     33 		return nil, nil
     34 	}
     35 
     36 	// Sanity check group count. Max is 16 on BSD.
     37 	if n < 0 || n > 1000 {
     38 		return nil, EINVAL
     39 	}
     40 
     41 	a := make([]_Gid_t, n)
     42 	n, err = getgroups(n, &a[0])
     43 	if err != nil {
     44 		return nil, err
     45 	}
     46 	gids = make([]int, n)
     47 	for i, v := range a[0:n] {
     48 		gids[i] = int(v)
     49 	}
     50 	return
     51 }
     52 
     53 func Setgroups(gids []int) (err error) {
     54 	if len(gids) == 0 {
     55 		return setgroups(0, nil)
     56 	}
     57 
     58 	a := make([]_Gid_t, len(gids))
     59 	for i, v := range gids {
     60 		a[i] = _Gid_t(v)
     61 	}
     62 	return setgroups(len(a), &a[0])
     63 }
     64 
     65 func ReadDirent(fd int, buf []byte) (n int, err error) {
     66 	// Final argument is (basep *uintptr) and the syscall doesn't take nil.
     67 	// 64 bits should be enough. (32 bits isn't even on 386). Since the
     68 	// actual system call is getdirentries64, 64 is a good guess.
     69 	// TODO(rsc): Can we use a single global basep for all calls?
     70 	var base = (*uintptr)(unsafe.Pointer(new(uint64)))
     71 	return Getdirentries(fd, buf, base)
     72 }
     73 
     74 // Wait status is 7 bits at bottom, either 0 (exited),
     75 // 0x7F (stopped), or a signal number that caused an exit.
     76 // The 0x80 bit is whether there was a core dump.
     77 // An extra number (exit code, signal causing a stop)
     78 // is in the high bits.
     79 
     80 type WaitStatus uint32
     81 
     82 const (
     83 	mask  = 0x7F
     84 	core  = 0x80
     85 	shift = 8
     86 
     87 	exited  = 0
     88 	stopped = 0x7F
     89 )
     90 
     91 func (w WaitStatus) Exited() bool { return w&mask == exited }
     92 
     93 func (w WaitStatus) ExitStatus() int {
     94 	if w&mask != exited {
     95 		return -1
     96 	}
     97 	return int(w >> shift)
     98 }
     99 
    100 func (w WaitStatus) Signaled() bool { return w&mask != stopped && w&mask != 0 }
    101 
    102 func (w WaitStatus) Signal() Signal {
    103 	sig := Signal(w & mask)
    104 	if sig == stopped || sig == 0 {
    105 		return -1
    106 	}
    107 	return sig
    108 }
    109 
    110 func (w WaitStatus) CoreDump() bool { return w.Signaled() && w&core != 0 }
    111 
    112 func (w WaitStatus) Stopped() bool { return w&mask == stopped && Signal(w>>shift) != SIGSTOP }
    113 
    114 func (w WaitStatus) Continued() bool { return w&mask == stopped && Signal(w>>shift) == SIGSTOP }
    115 
    116 func (w WaitStatus) StopSignal() Signal {
    117 	if !w.Stopped() {
    118 		return -1
    119 	}
    120 	return Signal(w>>shift) & 0xFF
    121 }
    122 
    123 func (w WaitStatus) TrapCause() int { return -1 }
    124 
    125 //sys	wait4(pid int, wstatus *_C_int, options int, rusage *Rusage) (wpid int, err error)
    126 
    127 func Wait4(pid int, wstatus *WaitStatus, options int, rusage *Rusage) (wpid int, err error) {
    128 	var status _C_int
    129 	wpid, err = wait4(pid, &status, options, rusage)
    130 	if wstatus != nil {
    131 		*wstatus = WaitStatus(status)
    132 	}
    133 	return
    134 }
    135 
    136 //sys	accept(s int, rsa *RawSockaddrAny, addrlen *_Socklen) (fd int, err error)
    137 //sys	bind(s int, addr unsafe.Pointer, addrlen _Socklen) (err error)
    138 //sys	connect(s int, addr unsafe.Pointer, addrlen _Socklen) (err error)
    139 //sysnb	socket(domain int, typ int, proto int) (fd int, err error)
    140 //sys	getsockopt(s int, level int, name int, val unsafe.Pointer, vallen *_Socklen) (err error)
    141 //sys	setsockopt(s int, level int, name int, val unsafe.Pointer, vallen uintptr) (err error)
    142 //sysnb	getpeername(fd int, rsa *RawSockaddrAny, addrlen *_Socklen) (err error)
    143 //sysnb	getsockname(fd int, rsa *RawSockaddrAny, addrlen *_Socklen) (err error)
    144 //sys	Shutdown(s int, how int) (err error)
    145 
    146 func (sa *SockaddrInet4) sockaddr() (unsafe.Pointer, _Socklen, error) {
    147 	if sa.Port < 0 || sa.Port > 0xFFFF {
    148 		return nil, 0, EINVAL
    149 	}
    150 	sa.raw.Len = SizeofSockaddrInet4
    151 	sa.raw.Family = AF_INET
    152 	p := (*[2]byte)(unsafe.Pointer(&sa.raw.Port))
    153 	p[0] = byte(sa.Port >> 8)
    154 	p[1] = byte(sa.Port)
    155 	for i := 0; i < len(sa.Addr); i++ {
    156 		sa.raw.Addr[i] = sa.Addr[i]
    157 	}
    158 	return unsafe.Pointer(&sa.raw), _Socklen(sa.raw.Len), nil
    159 }
    160 
    161 func (sa *SockaddrInet6) sockaddr() (unsafe.Pointer, _Socklen, error) {
    162 	if sa.Port < 0 || sa.Port > 0xFFFF {
    163 		return nil, 0, EINVAL
    164 	}
    165 	sa.raw.Len = SizeofSockaddrInet6
    166 	sa.raw.Family = AF_INET6
    167 	p := (*[2]byte)(unsafe.Pointer(&sa.raw.Port))
    168 	p[0] = byte(sa.Port >> 8)
    169 	p[1] = byte(sa.Port)
    170 	sa.raw.Scope_id = sa.ZoneId
    171 	for i := 0; i < len(sa.Addr); i++ {
    172 		sa.raw.Addr[i] = sa.Addr[i]
    173 	}
    174 	return unsafe.Pointer(&sa.raw), _Socklen(sa.raw.Len), nil
    175 }
    176 
    177 func (sa *SockaddrUnix) sockaddr() (unsafe.Pointer, _Socklen, error) {
    178 	name := sa.Name
    179 	n := len(name)
    180 	if n >= len(sa.raw.Path) || n == 0 {
    181 		return nil, 0, EINVAL
    182 	}
    183 	sa.raw.Len = byte(3 + n) // 2 for Family, Len; 1 for NUL
    184 	sa.raw.Family = AF_UNIX
    185 	for i := 0; i < n; i++ {
    186 		sa.raw.Path[i] = int8(name[i])
    187 	}
    188 	return unsafe.Pointer(&sa.raw), _Socklen(sa.raw.Len), nil
    189 }
    190 
    191 func (sa *SockaddrDatalink) sockaddr() (unsafe.Pointer, _Socklen, error) {
    192 	if sa.Index == 0 {
    193 		return nil, 0, EINVAL
    194 	}
    195 	sa.raw.Len = sa.Len
    196 	sa.raw.Family = AF_LINK
    197 	sa.raw.Index = sa.Index
    198 	sa.raw.Type = sa.Type
    199 	sa.raw.Nlen = sa.Nlen
    200 	sa.raw.Alen = sa.Alen
    201 	sa.raw.Slen = sa.Slen
    202 	for i := 0; i < len(sa.raw.Data); i++ {
    203 		sa.raw.Data[i] = sa.Data[i]
    204 	}
    205 	return unsafe.Pointer(&sa.raw), SizeofSockaddrDatalink, nil
    206 }
    207 
    208 func anyToSockaddr(rsa *RawSockaddrAny) (Sockaddr, error) {
    209 	switch rsa.Addr.Family {
    210 	case AF_LINK:
    211 		pp := (*RawSockaddrDatalink)(unsafe.Pointer(rsa))
    212 		sa := new(SockaddrDatalink)
    213 		sa.Len = pp.Len
    214 		sa.Family = pp.Family
    215 		sa.Index = pp.Index
    216 		sa.Type = pp.Type
    217 		sa.Nlen = pp.Nlen
    218 		sa.Alen = pp.Alen
    219 		sa.Slen = pp.Slen
    220 		for i := 0; i < len(sa.Data); i++ {
    221 			sa.Data[i] = pp.Data[i]
    222 		}
    223 		return sa, nil
    224 
    225 	case AF_UNIX:
    226 		pp := (*RawSockaddrUnix)(unsafe.Pointer(rsa))
    227 		if pp.Len < 2 || pp.Len > SizeofSockaddrUnix {
    228 			return nil, EINVAL
    229 		}
    230 		sa := new(SockaddrUnix)
    231 
    232 		// Some BSDs include the trailing NUL in the length, whereas
    233 		// others do not. Work around this by subtracting the leading
    234 		// family and len. The path is then scanned to see if a NUL
    235 		// terminator still exists within the length.
    236 		n := int(pp.Len) - 2 // subtract leading Family, Len
    237 		for i := 0; i < n; i++ {
    238 			if pp.Path[i] == 0 {
    239 				// found early NUL; assume Len included the NUL
    240 				// or was overestimating.
    241 				n = i
    242 				break
    243 			}
    244 		}
    245 		bytes := (*[10000]byte)(unsafe.Pointer(&pp.Path[0]))[0:n]
    246 		sa.Name = string(bytes)
    247 		return sa, nil
    248 
    249 	case AF_INET:
    250 		pp := (*RawSockaddrInet4)(unsafe.Pointer(rsa))
    251 		sa := new(SockaddrInet4)
    252 		p := (*[2]byte)(unsafe.Pointer(&pp.Port))
    253 		sa.Port = int(p[0])<<8 + int(p[1])
    254 		for i := 0; i < len(sa.Addr); i++ {
    255 			sa.Addr[i] = pp.Addr[i]
    256 		}
    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 		for i := 0; i < len(sa.Addr); i++ {
    266 			sa.Addr[i] = pp.Addr[i]
    267 		}
    268 		return sa, nil
    269 	}
    270 	return nil, EAFNOSUPPORT
    271 }
    272 
    273 func Accept(fd int) (nfd int, sa Sockaddr, err error) {
    274 	var rsa RawSockaddrAny
    275 	var len _Socklen = SizeofSockaddrAny
    276 	nfd, err = accept(fd, &rsa, &len)
    277 	if err != nil {
    278 		return
    279 	}
    280 	if runtime.GOOS == "darwin" && len == 0 {
    281 		// Accepted socket has no address.
    282 		// This is likely due to a bug in xnu kernels,
    283 		// where instead of ECONNABORTED error socket
    284 		// is accepted, but has no address.
    285 		Close(nfd)
    286 		return 0, nil, ECONNABORTED
    287 	}
    288 	sa, err = anyToSockaddr(&rsa)
    289 	if err != nil {
    290 		Close(nfd)
    291 		nfd = 0
    292 	}
    293 	return
    294 }
    295 
    296 func Getsockname(fd int) (sa Sockaddr, err error) {
    297 	var rsa RawSockaddrAny
    298 	var len _Socklen = SizeofSockaddrAny
    299 	if err = getsockname(fd, &rsa, &len); err != nil {
    300 		return
    301 	}
    302 	// TODO(jsing): DragonFly has a "bug" (see issue 3349), which should be
    303 	// reported upstream.
    304 	if runtime.GOOS == "dragonfly" && rsa.Addr.Family == AF_UNSPEC && rsa.Addr.Len == 0 {
    305 		rsa.Addr.Family = AF_UNIX
    306 		rsa.Addr.Len = SizeofSockaddrUnix
    307 	}
    308 	return anyToSockaddr(&rsa)
    309 }
    310 
    311 //sysnb socketpair(domain int, typ int, proto int, fd *[2]int32) (err error)
    312 
    313 func GetsockoptByte(fd, level, opt int) (value byte, err error) {
    314 	var n byte
    315 	vallen := _Socklen(1)
    316 	err = getsockopt(fd, level, opt, unsafe.Pointer(&n), &vallen)
    317 	return n, err
    318 }
    319 
    320 func GetsockoptInet4Addr(fd, level, opt int) (value [4]byte, err error) {
    321 	vallen := _Socklen(4)
    322 	err = getsockopt(fd, level, opt, unsafe.Pointer(&value[0]), &vallen)
    323 	return value, err
    324 }
    325 
    326 func GetsockoptIPMreq(fd, level, opt int) (*IPMreq, error) {
    327 	var value IPMreq
    328 	vallen := _Socklen(SizeofIPMreq)
    329 	err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
    330 	return &value, err
    331 }
    332 
    333 func GetsockoptIPv6Mreq(fd, level, opt int) (*IPv6Mreq, error) {
    334 	var value IPv6Mreq
    335 	vallen := _Socklen(SizeofIPv6Mreq)
    336 	err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
    337 	return &value, err
    338 }
    339 
    340 func GetsockoptIPv6MTUInfo(fd, level, opt int) (*IPv6MTUInfo, error) {
    341 	var value IPv6MTUInfo
    342 	vallen := _Socklen(SizeofIPv6MTUInfo)
    343 	err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
    344 	return &value, err
    345 }
    346 
    347 func GetsockoptICMPv6Filter(fd, level, opt int) (*ICMPv6Filter, error) {
    348 	var value ICMPv6Filter
    349 	vallen := _Socklen(SizeofICMPv6Filter)
    350 	err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
    351 	return &value, err
    352 }
    353 
    354 //sys   recvfrom(fd int, p []byte, flags int, from *RawSockaddrAny, fromlen *_Socklen) (n int, err error)
    355 //sys   sendto(s int, buf []byte, flags int, to unsafe.Pointer, addrlen _Socklen) (err error)
    356 //sys	recvmsg(s int, msg *Msghdr, flags int) (n int, err error)
    357 
    358 func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, err error) {
    359 	var msg Msghdr
    360 	var rsa RawSockaddrAny
    361 	msg.Name = (*byte)(unsafe.Pointer(&rsa))
    362 	msg.Namelen = uint32(SizeofSockaddrAny)
    363 	var iov Iovec
    364 	if len(p) > 0 {
    365 		iov.Base = (*byte)(unsafe.Pointer(&p[0]))
    366 		iov.SetLen(len(p))
    367 	}
    368 	var dummy byte
    369 	if len(oob) > 0 {
    370 		// receive at least one normal byte
    371 		if len(p) == 0 {
    372 			iov.Base = &dummy
    373 			iov.SetLen(1)
    374 		}
    375 		msg.Control = (*byte)(unsafe.Pointer(&oob[0]))
    376 		msg.SetControllen(len(oob))
    377 	}
    378 	msg.Iov = &iov
    379 	msg.Iovlen = 1
    380 	if n, err = recvmsg(fd, &msg, flags); err != nil {
    381 		return
    382 	}
    383 	oobn = int(msg.Controllen)
    384 	recvflags = int(msg.Flags)
    385 	// source address is only specified if the socket is unconnected
    386 	if rsa.Addr.Family != AF_UNSPEC {
    387 		from, err = anyToSockaddr(&rsa)
    388 	}
    389 	return
    390 }
    391 
    392 //sys	sendmsg(s int, msg *Msghdr, flags int) (n int, err error)
    393 
    394 func Sendmsg(fd int, p, oob []byte, to Sockaddr, flags int) (err error) {
    395 	_, err = SendmsgN(fd, p, oob, to, flags)
    396 	return
    397 }
    398 
    399 func SendmsgN(fd int, p, oob []byte, to Sockaddr, flags int) (n int, err error) {
    400 	var ptr unsafe.Pointer
    401 	var salen _Socklen
    402 	if to != nil {
    403 		ptr, salen, err = to.sockaddr()
    404 		if err != nil {
    405 			return 0, err
    406 		}
    407 	}
    408 	var msg Msghdr
    409 	msg.Name = (*byte)(unsafe.Pointer(ptr))
    410 	msg.Namelen = uint32(salen)
    411 	var iov Iovec
    412 	if len(p) > 0 {
    413 		iov.Base = (*byte)(unsafe.Pointer(&p[0]))
    414 		iov.SetLen(len(p))
    415 	}
    416 	var dummy byte
    417 	if len(oob) > 0 {
    418 		// send at least one normal byte
    419 		if len(p) == 0 {
    420 			iov.Base = &dummy
    421 			iov.SetLen(1)
    422 		}
    423 		msg.Control = (*byte)(unsafe.Pointer(&oob[0]))
    424 		msg.SetControllen(len(oob))
    425 	}
    426 	msg.Iov = &iov
    427 	msg.Iovlen = 1
    428 	if n, err = sendmsg(fd, &msg, flags); err != nil {
    429 		return 0, err
    430 	}
    431 	if len(oob) > 0 && len(p) == 0 {
    432 		n = 0
    433 	}
    434 	return n, nil
    435 }
    436 
    437 //sys	kevent(kq int, change unsafe.Pointer, nchange int, event unsafe.Pointer, nevent int, timeout *Timespec) (n int, err error)
    438 
    439 func Kevent(kq int, changes, events []Kevent_t, timeout *Timespec) (n int, err error) {
    440 	var change, event unsafe.Pointer
    441 	if len(changes) > 0 {
    442 		change = unsafe.Pointer(&changes[0])
    443 	}
    444 	if len(events) > 0 {
    445 		event = unsafe.Pointer(&events[0])
    446 	}
    447 	return kevent(kq, change, len(changes), event, len(events), timeout)
    448 }
    449 
    450 //sys	sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error) = SYS___SYSCTL
    451 
    452 func Sysctl(name string) (value string, err error) {
    453 	// Translate name to mib number.
    454 	mib, err := nametomib(name)
    455 	if err != nil {
    456 		return "", err
    457 	}
    458 
    459 	// Find size.
    460 	n := uintptr(0)
    461 	if err = sysctl(mib, nil, &n, nil, 0); err != nil {
    462 		return "", err
    463 	}
    464 	if n == 0 {
    465 		return "", nil
    466 	}
    467 
    468 	// Read into buffer of that size.
    469 	buf := make([]byte, n)
    470 	if err = sysctl(mib, &buf[0], &n, nil, 0); err != nil {
    471 		return "", err
    472 	}
    473 
    474 	// Throw away terminating NUL.
    475 	if n > 0 && buf[n-1] == '\x00' {
    476 		n--
    477 	}
    478 	return string(buf[0:n]), nil
    479 }
    480 
    481 func SysctlUint32(name string) (value uint32, err error) {
    482 	// Translate name to mib number.
    483 	mib, err := nametomib(name)
    484 	if err != nil {
    485 		return 0, err
    486 	}
    487 
    488 	// Read into buffer of that size.
    489 	n := uintptr(4)
    490 	buf := make([]byte, 4)
    491 	if err = sysctl(mib, &buf[0], &n, nil, 0); err != nil {
    492 		return 0, err
    493 	}
    494 	if n != 4 {
    495 		return 0, EIO
    496 	}
    497 	return *(*uint32)(unsafe.Pointer(&buf[0])), nil
    498 }
    499 
    500 //sys	utimes(path string, timeval *[2]Timeval) (err error)
    501 
    502 func Utimes(path string, tv []Timeval) (err error) {
    503 	if len(tv) != 2 {
    504 		return EINVAL
    505 	}
    506 	return utimes(path, (*[2]Timeval)(unsafe.Pointer(&tv[0])))
    507 }
    508 
    509 func UtimesNano(path string, ts []Timespec) error {
    510 	// TODO: The BSDs can do utimensat with SYS_UTIMENSAT but it
    511 	// isn't supported by darwin so this uses utimes instead
    512 	if len(ts) != 2 {
    513 		return EINVAL
    514 	}
    515 	// Not as efficient as it could be because Timespec and
    516 	// Timeval have different types in the different OSes
    517 	tv := [2]Timeval{
    518 		NsecToTimeval(TimespecToNsec(ts[0])),
    519 		NsecToTimeval(TimespecToNsec(ts[1])),
    520 	}
    521 	return utimes(path, (*[2]Timeval)(unsafe.Pointer(&tv[0])))
    522 }
    523 
    524 //sys	futimes(fd int, timeval *[2]Timeval) (err error)
    525 
    526 func Futimes(fd int, tv []Timeval) (err error) {
    527 	if len(tv) != 2 {
    528 		return EINVAL
    529 	}
    530 	return futimes(fd, (*[2]Timeval)(unsafe.Pointer(&tv[0])))
    531 }
    532 
    533 //sys	fcntl(fd int, cmd int, arg int) (val int, err error)
    534 
    535 // TODO: wrap
    536 //	Acct(name nil-string) (err error)
    537 //	Gethostuuid(uuid *byte, timeout *Timespec) (err error)
    538 //	Madvise(addr *byte, len int, behav int) (err error)
    539 //	Mprotect(addr *byte, len int, prot int) (err error)
    540 //	Msync(addr *byte, len int, flags int) (err error)
    541 //	Ptrace(req int, pid int, addr uintptr, data int) (ret uintptr, err error)
    542 
    543 var mapper = &mmapper{
    544 	active: make(map[*byte][]byte),
    545 	mmap:   mmap,
    546 	munmap: munmap,
    547 }
    548 
    549 func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
    550 	return mapper.Mmap(fd, offset, length, prot, flags)
    551 }
    552 
    553 func Munmap(b []byte) (err error) {
    554 	return mapper.Munmap(b)
    555 }
    556