src

syscall_darwin.go (25237B)

---

 // Copyright 2009,2010 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 // Darwin system calls.
 // This file is compiled as ordinary Go code,
 // but it is also input to mksyscall,
 // which parses the //sys lines and generates system call stubs.
 // Note that sometimes we use a lowercase //sys name and wrap
 // it in our own nicer implementation, either here or in
 // syscall_bsd.go or syscall_unix.go.
 
 package unix
 
 import (
 	"fmt"
 	"syscall"
 	"unsafe"
 )
 
 //sys	closedir(dir uintptr) (err error)
 //sys	readdir_r(dir uintptr, entry *Dirent, result **Dirent) (res Errno)
 
 func fdopendir(fd int) (dir uintptr, err error) {
 	r0, _, e1 := syscall_syscallPtr(libc_fdopendir_trampoline_addr, uintptr(fd), 0, 0)
 	dir = uintptr(r0)
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
 	return
 }
 
 var libc_fdopendir_trampoline_addr uintptr
 
 //go:cgo_import_dynamic libc_fdopendir fdopendir "/usr/lib/libSystem.B.dylib"
 
 func Getdirentries(fd int, buf []byte, basep *uintptr) (n int, err error) {
 	// Simulate Getdirentries using fdopendir/readdir_r/closedir.
 	// We store the number of entries to skip in the seek
 	// offset of fd. See issue #31368.
 	// It's not the full required semantics, but should handle the case
 	// of calling Getdirentries or ReadDirent repeatedly.
 	// It won't handle assigning the results of lseek to *basep, or handle
 	// the directory being edited underfoot.
 	skip, err := Seek(fd, 0, 1 /* SEEK_CUR */)
 	if err != nil {
 		return 0, err
 	}
 
 	// We need to duplicate the incoming file descriptor
 	// because the caller expects to retain control of it, but
 	// fdopendir expects to take control of its argument.
 	// Just Dup'ing the file descriptor is not enough, as the
 	// result shares underlying state. Use Openat to make a really
 	// new file descriptor referring to the same directory.
 	fd2, err := Openat(fd, ".", O_RDONLY, 0)
 	if err != nil {
 		return 0, err
 	}
 	d, err := fdopendir(fd2)
 	if err != nil {
 		Close(fd2)
 		return 0, err
 	}
 	defer closedir(d)
 
 	var cnt int64
 	for {
 		var entry Dirent
 		var entryp *Dirent
 		e := readdir_r(d, &entry, &entryp)
 		if e != 0 {
 			return n, errnoErr(e)
 		}
 		if entryp == nil {
 			break
 		}
 		if skip > 0 {
 			skip--
 			cnt++
 			continue
 		}
 
 		reclen := int(entry.Reclen)
 		if reclen > len(buf) {
 			// Not enough room. Return for now.
 			// The counter will let us know where we should start up again.
 			// Note: this strategy for suspending in the middle and
 			// restarting is O(n^2) in the length of the directory. Oh well.
 			break
 		}
 
 		// Copy entry into return buffer.
 		s := unsafe.Slice((*byte)(unsafe.Pointer(&entry)), reclen)
 		copy(buf, s)
 
 		buf = buf[reclen:]
 		n += reclen
 		cnt++
 	}
 	// Set the seek offset of the input fd to record
 	// how many files we've already returned.
 	_, err = Seek(fd, cnt, 0 /* SEEK_SET */)
 	if err != nil {
 		return n, err
 	}
 
 	return n, nil
 }
 
 // SockaddrDatalink implements the Sockaddr interface for AF_LINK type sockets.
 type SockaddrDatalink struct {
 	Len    uint8
 	Family uint8
 	Index  uint16
 	Type   uint8
 	Nlen   uint8
 	Alen   uint8
 	Slen   uint8
 	Data   [12]int8
 	raw    RawSockaddrDatalink
 }
 
 // SockaddrCtl implements the Sockaddr interface for AF_SYSTEM type sockets.
 type SockaddrCtl struct {
 	ID   uint32
 	Unit uint32
 	raw  RawSockaddrCtl
 }
 
 func (sa *SockaddrCtl) sockaddr() (unsafe.Pointer, _Socklen, error) {
 	sa.raw.Sc_len = SizeofSockaddrCtl
 	sa.raw.Sc_family = AF_SYSTEM
 	sa.raw.Ss_sysaddr = AF_SYS_CONTROL
 	sa.raw.Sc_id = sa.ID
 	sa.raw.Sc_unit = sa.Unit
 	return unsafe.Pointer(&sa.raw), SizeofSockaddrCtl, nil
 }
 
 // SockaddrVM implements the Sockaddr interface for AF_VSOCK type sockets.
 // SockaddrVM provides access to Darwin VM sockets: a mechanism that enables
 // bidirectional communication between a hypervisor and its guest virtual
 // machines.
 type SockaddrVM struct {
 	// CID and Port specify a context ID and port address for a VM socket.
 	// Guests have a unique CID, and hosts may have a well-known CID of:
 	//  - VMADDR_CID_HYPERVISOR: refers to the hypervisor process.
 	//  - VMADDR_CID_LOCAL: refers to local communication (loopback).
 	//  - VMADDR_CID_HOST: refers to other processes on the host.
 	CID  uint32
 	Port uint32
 	raw  RawSockaddrVM
 }
 
 func (sa *SockaddrVM) sockaddr() (unsafe.Pointer, _Socklen, error) {
 	sa.raw.Len = SizeofSockaddrVM
 	sa.raw.Family = AF_VSOCK
 	sa.raw.Port = sa.Port
 	sa.raw.Cid = sa.CID
 
 	return unsafe.Pointer(&sa.raw), SizeofSockaddrVM, nil
 }
 
 func anyToSockaddrGOOS(fd int, rsa *RawSockaddrAny) (Sockaddr, error) {
 	switch rsa.Addr.Family {
 	case AF_SYSTEM:
 		pp := (*RawSockaddrCtl)(unsafe.Pointer(rsa))
 		if pp.Ss_sysaddr == AF_SYS_CONTROL {
 			sa := new(SockaddrCtl)
 			sa.ID = pp.Sc_id
 			sa.Unit = pp.Sc_unit
 			return sa, nil
 		}
 	case AF_VSOCK:
 		pp := (*RawSockaddrVM)(unsafe.Pointer(rsa))
 		sa := &SockaddrVM{
 			CID:  pp.Cid,
 			Port: pp.Port,
 		}
 		return sa, nil
 	}
 	return nil, EAFNOSUPPORT
 }
 
 // Some external packages rely on SYS___SYSCTL being defined to implement their
 // own sysctl wrappers. Provide it here, even though direct syscalls are no
 // longer supported on darwin.
 const SYS___SYSCTL = SYS_SYSCTL
 
 // Translate "kern.hostname" to []_C_int{0,1,2,3}.
 func nametomib(name string) (mib []_C_int, err error) {
 	const siz = unsafe.Sizeof(mib[0])
 
 	// NOTE(rsc): It seems strange to set the buffer to have
 	// size CTL_MAXNAME+2 but use only CTL_MAXNAME
 	// as the size. I don't know why the +2 is here, but the
 	// kernel uses +2 for its own implementation of this function.
 	// I am scared that if we don't include the +2 here, the kernel
 	// will silently write 2 words farther than we specify
 	// and we'll get memory corruption.
 	var buf [CTL_MAXNAME + 2]_C_int
 	n := uintptr(CTL_MAXNAME) * siz
 
 	p := (*byte)(unsafe.Pointer(&buf[0]))
 	bytes, err := ByteSliceFromString(name)
 	if err != nil {
 		return nil, err
 	}
 
 	// Magic sysctl: "setting" 0.3 to a string name
 	// lets you read back the array of integers form.
 	if err = sysctl([]_C_int{0, 3}, p, &n, &bytes[0], uintptr(len(name))); err != nil {
 		return nil, err
 	}
 	return buf[0 : n/siz], nil
 }
 
 func direntIno(buf []byte) (uint64, bool) {
 	return readInt(buf, unsafe.Offsetof(Dirent{}.Ino), unsafe.Sizeof(Dirent{}.Ino))
 }
 
 func direntReclen(buf []byte) (uint64, bool) {
 	return readInt(buf, unsafe.Offsetof(Dirent{}.Reclen), unsafe.Sizeof(Dirent{}.Reclen))
 }
 
 func direntNamlen(buf []byte) (uint64, bool) {
 	return readInt(buf, unsafe.Offsetof(Dirent{}.Namlen), unsafe.Sizeof(Dirent{}.Namlen))
 }
 
 func PtraceAttach(pid int) (err error) { return ptrace(PT_ATTACH, pid, 0, 0) }
 func PtraceDetach(pid int) (err error) { return ptrace(PT_DETACH, pid, 0, 0) }
 func PtraceDenyAttach() (err error)    { return ptrace(PT_DENY_ATTACH, 0, 0, 0) }
 
 //sysnb	pipe(p *[2]int32) (err error)
 
 func Pipe(p []int) (err error) {
 	if len(p) != 2 {
 		return EINVAL
 	}
 	var x [2]int32
 	err = pipe(&x)
 	if err == nil {
 		p[0] = int(x[0])
 		p[1] = int(x[1])
 	}
 	return
 }
 
 func Getfsstat(buf []Statfs_t, flags int) (n int, err error) {
 	var _p0 unsafe.Pointer
 	var bufsize uintptr
 	if len(buf) > 0 {
 		_p0 = unsafe.Pointer(&buf[0])
 		bufsize = unsafe.Sizeof(Statfs_t{}) * uintptr(len(buf))
 	}
 	return getfsstat(_p0, bufsize, flags)
 }
 
 func xattrPointer(dest []byte) *byte {
 	// It's only when dest is set to NULL that the OS X implementations of
 	// getxattr() and listxattr() return the current sizes of the named attributes.
 	// An empty byte array is not sufficient. To maintain the same behaviour as the
 	// linux implementation, we wrap around the system calls and pass in NULL when
 	// dest is empty.
 	var destp *byte
 	if len(dest) > 0 {
 		destp = &dest[0]
 	}
 	return destp
 }
 
 //sys	getxattr(path string, attr string, dest *byte, size int, position uint32, options int) (sz int, err error)
 
 func Getxattr(path string, attr string, dest []byte) (sz int, err error) {
 	return getxattr(path, attr, xattrPointer(dest), len(dest), 0, 0)
 }
 
 func Lgetxattr(link string, attr string, dest []byte) (sz int, err error) {
 	return getxattr(link, attr, xattrPointer(dest), len(dest), 0, XATTR_NOFOLLOW)
 }
 
 //sys	fgetxattr(fd int, attr string, dest *byte, size int, position uint32, options int) (sz int, err error)
 
 func Fgetxattr(fd int, attr string, dest []byte) (sz int, err error) {
 	return fgetxattr(fd, attr, xattrPointer(dest), len(dest), 0, 0)
 }
 
 //sys	setxattr(path string, attr string, data *byte, size int, position uint32, options int) (err error)
 
 func Setxattr(path string, attr string, data []byte, flags int) (err error) {
 	// The parameters for the OS X implementation vary slightly compared to the
 	// linux system call, specifically the position parameter:
 	//
 	//  linux:
 	//      int setxattr(
 	//          const char *path,
 	//          const char *name,
 	//          const void *value,
 	//          size_t size,
 	//          int flags
 	//      );
 	//
 	//  darwin:
 	//      int setxattr(
 	//          const char *path,
 	//          const char *name,
 	//          void *value,
 	//          size_t size,
 	//          u_int32_t position,
 	//          int options
 	//      );
 	//
 	// position specifies the offset within the extended attribute. In the
 	// current implementation, only the resource fork extended attribute makes
 	// use of this argument. For all others, position is reserved. We simply
 	// default to setting it to zero.
 	return setxattr(path, attr, xattrPointer(data), len(data), 0, flags)
 }
 
 func Lsetxattr(link string, attr string, data []byte, flags int) (err error) {
 	return setxattr(link, attr, xattrPointer(data), len(data), 0, flags|XATTR_NOFOLLOW)
 }
 
 //sys	fsetxattr(fd int, attr string, data *byte, size int, position uint32, options int) (err error)
 
 func Fsetxattr(fd int, attr string, data []byte, flags int) (err error) {
 	return fsetxattr(fd, attr, xattrPointer(data), len(data), 0, 0)
 }
 
 //sys	removexattr(path string, attr string, options int) (err error)
 
 func Removexattr(path string, attr string) (err error) {
 	// We wrap around and explicitly zero out the options provided to the OS X
 	// implementation of removexattr, we do so for interoperability with the
 	// linux variant.
 	return removexattr(path, attr, 0)
 }
 
 func Lremovexattr(link string, attr string) (err error) {
 	return removexattr(link, attr, XATTR_NOFOLLOW)
 }
 
 //sys	fremovexattr(fd int, attr string, options int) (err error)
 
 func Fremovexattr(fd int, attr string) (err error) {
 	return fremovexattr(fd, attr, 0)
 }
 
 //sys	listxattr(path string, dest *byte, size int, options int) (sz int, err error)
 
 func Listxattr(path string, dest []byte) (sz int, err error) {
 	return listxattr(path, xattrPointer(dest), len(dest), 0)
 }
 
 func Llistxattr(link string, dest []byte) (sz int, err error) {
 	return listxattr(link, xattrPointer(dest), len(dest), XATTR_NOFOLLOW)
 }
 
 //sys	flistxattr(fd int, dest *byte, size int, options int) (sz int, err error)
 
 func Flistxattr(fd int, dest []byte) (sz int, err error) {
 	return flistxattr(fd, xattrPointer(dest), len(dest), 0)
 }
 
 //sys	utimensat(dirfd int, path string, times *[2]Timespec, flags int) (err error)
 
 /*
  * Wrapped
  */
 
 //sys	fcntl(fd int, cmd int, arg int) (val int, err error)
 
 //sys	kill(pid int, signum int, posix int) (err error)
 
 func Kill(pid int, signum syscall.Signal) (err error) { return kill(pid, int(signum), 1) }
 
 //sys	ioctl(fd int, req uint, arg uintptr) (err error)
 //sys	ioctlPtr(fd int, req uint, arg unsafe.Pointer) (err error) = SYS_IOCTL
 
 func IoctlCtlInfo(fd int, ctlInfo *CtlInfo) error {
 	return ioctlPtr(fd, CTLIOCGINFO, unsafe.Pointer(ctlInfo))
 }
 
 // IfreqMTU is struct ifreq used to get or set a network device's MTU.
 type IfreqMTU struct {
 	Name [IFNAMSIZ]byte
 	MTU  int32
 }
 
 // IoctlGetIfreqMTU performs the SIOCGIFMTU ioctl operation on fd to get the MTU
 // of the network device specified by ifname.
 func IoctlGetIfreqMTU(fd int, ifname string) (*IfreqMTU, error) {
 	var ifreq IfreqMTU
 	copy(ifreq.Name[:], ifname)
 	err := ioctlPtr(fd, SIOCGIFMTU, unsafe.Pointer(&ifreq))
 	return &ifreq, err
 }
 
 // IoctlSetIfreqMTU performs the SIOCSIFMTU ioctl operation on fd to set the MTU
 // of the network device specified by ifreq.Name.
 func IoctlSetIfreqMTU(fd int, ifreq *IfreqMTU) error {
 	return ioctlPtr(fd, SIOCSIFMTU, unsafe.Pointer(ifreq))
 }
 
 //sys	renamexNp(from string, to string, flag uint32) (err error)
 
 func RenamexNp(from string, to string, flag uint32) (err error) {
 	return renamexNp(from, to, flag)
 }
 
 //sys	renameatxNp(fromfd int, from string, tofd int, to string, flag uint32) (err error)
 
 func RenameatxNp(fromfd int, from string, tofd int, to string, flag uint32) (err error) {
 	return renameatxNp(fromfd, from, tofd, to, flag)
 }
 
 //sys	sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error) = SYS_SYSCTL
 
 func Uname(uname *Utsname) error {
 	mib := []_C_int{CTL_KERN, KERN_OSTYPE}
 	n := unsafe.Sizeof(uname.Sysname)
 	if err := sysctl(mib, &uname.Sysname[0], &n, nil, 0); err != nil {
 		return err
 	}
 
 	mib = []_C_int{CTL_KERN, KERN_HOSTNAME}
 	n = unsafe.Sizeof(uname.Nodename)
 	if err := sysctl(mib, &uname.Nodename[0], &n, nil, 0); err != nil {
 		return err
 	}
 
 	mib = []_C_int{CTL_KERN, KERN_OSRELEASE}
 	n = unsafe.Sizeof(uname.Release)
 	if err := sysctl(mib, &uname.Release[0], &n, nil, 0); err != nil {
 		return err
 	}
 
 	mib = []_C_int{CTL_KERN, KERN_VERSION}
 	n = unsafe.Sizeof(uname.Version)
 	if err := sysctl(mib, &uname.Version[0], &n, nil, 0); err != nil {
 		return err
 	}
 
 	// The version might have newlines or tabs in it, convert them to
 	// spaces.
 	for i, b := range uname.Version {
 		if b == '\n' || b == '\t' {
 			if i == len(uname.Version)-1 {
 				uname.Version[i] = 0
 			} else {
 				uname.Version[i] = ' '
 			}
 		}
 	}
 
 	mib = []_C_int{CTL_HW, HW_MACHINE}
 	n = unsafe.Sizeof(uname.Machine)
 	if err := sysctl(mib, &uname.Machine[0], &n, nil, 0); err != nil {
 		return err
 	}
 
 	return nil
 }
 
 func Sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) {
 	if raceenabled {
 		raceReleaseMerge(unsafe.Pointer(&ioSync))
 	}
 	var length = int64(count)
 	err = sendfile(infd, outfd, *offset, &length, nil, 0)
 	written = int(length)
 	return
 }
 
 func GetsockoptIPMreqn(fd, level, opt int) (*IPMreqn, error) {
 	var value IPMreqn
 	vallen := _Socklen(SizeofIPMreqn)
 	errno := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
 	return &value, errno
 }
 
 func SetsockoptIPMreqn(fd, level, opt int, mreq *IPMreqn) (err error) {
 	return setsockopt(fd, level, opt, unsafe.Pointer(mreq), unsafe.Sizeof(*mreq))
 }
 
 // GetsockoptXucred is a getsockopt wrapper that returns an Xucred struct.
 // The usual level and opt are SOL_LOCAL and LOCAL_PEERCRED, respectively.
 func GetsockoptXucred(fd, level, opt int) (*Xucred, error) {
 	x := new(Xucred)
 	vallen := _Socklen(SizeofXucred)
 	err := getsockopt(fd, level, opt, unsafe.Pointer(x), &vallen)
 	return x, err
 }
 
 func GetsockoptTCPConnectionInfo(fd, level, opt int) (*TCPConnectionInfo, error) {
 	var value TCPConnectionInfo
 	vallen := _Socklen(SizeofTCPConnectionInfo)
 	err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
 	return &value, err
 }
 
 func SysctlKinfoProc(name string, args ...int) (*KinfoProc, error) {
 	mib, err := sysctlmib(name, args...)
 	if err != nil {
 		return nil, err
 	}
 
 	var kinfo KinfoProc
 	n := uintptr(SizeofKinfoProc)
 	if err := sysctl(mib, (*byte)(unsafe.Pointer(&kinfo)), &n, nil, 0); err != nil {
 		return nil, err
 	}
 	if n != SizeofKinfoProc {
 		return nil, EIO
 	}
 	return &kinfo, nil
 }
 
 func SysctlKinfoProcSlice(name string, args ...int) ([]KinfoProc, error) {
 	mib, err := sysctlmib(name, args...)
 	if err != nil {
 		return nil, err
 	}
 
 	for {
 		// Find size.
 		n := uintptr(0)
 		if err := sysctl(mib, nil, &n, nil, 0); err != nil {
 			return nil, err
 		}
 		if n == 0 {
 			return nil, nil
 		}
 		if n%SizeofKinfoProc != 0 {
 			return nil, fmt.Errorf("sysctl() returned a size of %d, which is not a multiple of %d", n, SizeofKinfoProc)
 		}
 
 		// Read into buffer of that size.
 		buf := make([]KinfoProc, n/SizeofKinfoProc)
 		if err := sysctl(mib, (*byte)(unsafe.Pointer(&buf[0])), &n, nil, 0); err != nil {
 			if err == ENOMEM {
 				// Process table grew. Try again.
 				continue
 			}
 			return nil, err
 		}
 		if n%SizeofKinfoProc != 0 {
 			return nil, fmt.Errorf("sysctl() returned a size of %d, which is not a multiple of %d", n, SizeofKinfoProc)
 		}
 
 		// The actual call may return less than the original reported required
 		// size so ensure we deal with that.
 		return buf[:n/SizeofKinfoProc], nil
 	}
 }
 
 //sys	pthread_chdir_np(path string) (err error)
 
 func PthreadChdir(path string) (err error) {
 	return pthread_chdir_np(path)
 }
 
 //sys	pthread_fchdir_np(fd int) (err error)
 
 func PthreadFchdir(fd int) (err error) {
 	return pthread_fchdir_np(fd)
 }
 
 // Connectx calls connectx(2) to initiate a connection on a socket.
 //
 // srcIf, srcAddr, and dstAddr are filled into a [SaEndpoints] struct and passed as the endpoints argument.
 //
 //   - srcIf is the optional source interface index. 0 means unspecified.
 //   - srcAddr is the optional source address. nil means unspecified.
 //   - dstAddr is the destination address.
 //
 // On success, Connectx returns the number of bytes enqueued for transmission.
 func Connectx(fd int, srcIf uint32, srcAddr, dstAddr Sockaddr, associd SaeAssocID, flags uint32, iov []Iovec, connid *SaeConnID) (n uintptr, err error) {
 	endpoints := SaEndpoints{
 		Srcif: srcIf,
 	}
 
 	if srcAddr != nil {
 		addrp, addrlen, err := srcAddr.sockaddr()
 		if err != nil {
 			return 0, err
 		}
 		endpoints.Srcaddr = (*RawSockaddr)(addrp)
 		endpoints.Srcaddrlen = uint32(addrlen)
 	}
 
 	if dstAddr != nil {
 		addrp, addrlen, err := dstAddr.sockaddr()
 		if err != nil {
 			return 0, err
 		}
 		endpoints.Dstaddr = (*RawSockaddr)(addrp)
 		endpoints.Dstaddrlen = uint32(addrlen)
 	}
 
 	err = connectx(fd, &endpoints, associd, flags, iov, &n, connid)
 	return
 }
 
 const minIovec = 8
 
 func Readv(fd int, iovs [][]byte) (n int, err error) {
 	iovecs := make([]Iovec, 0, minIovec)
 	iovecs = appendBytes(iovecs, iovs)
 	n, err = readv(fd, iovecs)
 	readvRacedetect(iovecs, n, err)
 	return n, err
 }
 
 func Preadv(fd int, iovs [][]byte, offset int64) (n int, err error) {
 	iovecs := make([]Iovec, 0, minIovec)
 	iovecs = appendBytes(iovecs, iovs)
 	n, err = preadv(fd, iovecs, offset)
 	readvRacedetect(iovecs, n, err)
 	return n, err
 }
 
 func Writev(fd int, iovs [][]byte) (n int, err error) {
 	iovecs := make([]Iovec, 0, minIovec)
 	iovecs = appendBytes(iovecs, iovs)
 	if raceenabled {
 		raceReleaseMerge(unsafe.Pointer(&ioSync))
 	}
 	n, err = writev(fd, iovecs)
 	writevRacedetect(iovecs, n)
 	return n, err
 }
 
 func Pwritev(fd int, iovs [][]byte, offset int64) (n int, err error) {
 	iovecs := make([]Iovec, 0, minIovec)
 	iovecs = appendBytes(iovecs, iovs)
 	if raceenabled {
 		raceReleaseMerge(unsafe.Pointer(&ioSync))
 	}
 	n, err = pwritev(fd, iovecs, offset)
 	writevRacedetect(iovecs, n)
 	return n, err
 }
 
 func appendBytes(vecs []Iovec, bs [][]byte) []Iovec {
 	for _, b := range bs {
 		var v Iovec
 		v.SetLen(len(b))
 		if len(b) > 0 {
 			v.Base = &b[0]
 		} else {
 			v.Base = (*byte)(unsafe.Pointer(&_zero))
 		}
 		vecs = append(vecs, v)
 	}
 	return vecs
 }
 
 func writevRacedetect(iovecs []Iovec, n int) {
 	if !raceenabled {
 		return
 	}
 	for i := 0; n > 0 && i < len(iovecs); i++ {
 		m := int(iovecs[i].Len)
 		if m > n {
 			m = n
 		}
 		n -= m
 		if m > 0 {
 			raceReadRange(unsafe.Pointer(iovecs[i].Base), m)
 		}
 	}
 }
 
 func readvRacedetect(iovecs []Iovec, n int, err error) {
 	if !raceenabled {
 		return
 	}
 	for i := 0; n > 0 && i < len(iovecs); i++ {
 		m := int(iovecs[i].Len)
 		if m > n {
 			m = n
 		}
 		n -= m
 		if m > 0 {
 			raceWriteRange(unsafe.Pointer(iovecs[i].Base), m)
 		}
 	}
 	if err == nil {
 		raceAcquire(unsafe.Pointer(&ioSync))
 	}
 }
 
 //sys	connectx(fd int, endpoints *SaEndpoints, associd SaeAssocID, flags uint32, iov []Iovec, n *uintptr, connid *SaeConnID) (err error)
 //sys	sendfile(infd int, outfd int, offset int64, len *int64, hdtr unsafe.Pointer, flags int) (err error)
 
 //sys	shmat(id int, addr uintptr, flag int) (ret uintptr, err error)
 //sys	shmctl(id int, cmd int, buf *SysvShmDesc) (result int, err error)
 //sys	shmdt(addr uintptr) (err error)
 //sys	shmget(key int, size int, flag int) (id int, err error)
 
 /*
  * Exposed directly
  */
 //sys	Access(path string, mode uint32) (err error)
 //sys	Adjtime(delta *Timeval, olddelta *Timeval) (err error)
 //sys	Chdir(path string) (err error)
 //sys	Chflags(path string, flags int) (err error)
 //sys	Chmod(path string, mode uint32) (err error)
 //sys	Chown(path string, uid int, gid int) (err error)
 //sys	Chroot(path string) (err error)
 //sys	ClockGettime(clockid int32, time *Timespec) (err error)
 //sys	Close(fd int) (err error)
 //sys	Clonefile(src string, dst string, flags int) (err error)
 //sys	Clonefileat(srcDirfd int, src string, dstDirfd int, dst string, flags int) (err error)
 //sys	Dup(fd int) (nfd int, err error)
 //sys	Dup2(from int, to int) (err error)
 //sys	Exchangedata(path1 string, path2 string, options int) (err error)
 //sys	Exit(code int)
 //sys	Faccessat(dirfd int, path string, mode uint32, flags int) (err error)
 //sys	Fchdir(fd int) (err error)
 //sys	Fchflags(fd int, flags int) (err error)
 //sys	Fchmod(fd int, mode uint32) (err error)
 //sys	Fchmodat(dirfd int, path string, mode uint32, flags int) (err error)
 //sys	Fchown(fd int, uid int, gid int) (err error)
 //sys	Fchownat(dirfd int, path string, uid int, gid int, flags int) (err error)
 //sys	Fclonefileat(srcDirfd int, dstDirfd int, dst string, flags int) (err error)
 //sys	Flock(fd int, how int) (err error)
 //sys	Fpathconf(fd int, name int) (val int, err error)
 //sys	Fsync(fd int) (err error)
 //sys	Ftruncate(fd int, length int64) (err error)
 //sys	Getcwd(buf []byte) (n int, err error)
 //sys	Getdtablesize() (size int)
 //sysnb	Getegid() (egid int)
 //sysnb	Geteuid() (uid int)
 //sysnb	Getgid() (gid int)
 //sysnb	Getpgid(pid int) (pgid int, err error)
 //sysnb	Getpgrp() (pgrp int)
 //sysnb	Getpid() (pid int)
 //sysnb	Getppid() (ppid int)
 //sys	Getpriority(which int, who int) (prio int, err error)
 //sysnb	Getrlimit(which int, lim *Rlimit) (err error)
 //sysnb	Getrusage(who int, rusage *Rusage) (err error)
 //sysnb	Getsid(pid int) (sid int, err error)
 //sysnb	Gettimeofday(tp *Timeval) (err error)
 //sysnb	Getuid() (uid int)
 //sysnb	Issetugid() (tainted bool)
 //sys	Kqueue() (fd int, err error)
 //sys	Lchown(path string, uid int, gid int) (err error)
 //sys	Link(path string, link string) (err error)
 //sys	Linkat(pathfd int, path string, linkfd int, link string, flags int) (err error)
 //sys	Listen(s int, backlog int) (err error)
 //sys	Mkdir(path string, mode uint32) (err error)
 //sys	Mkdirat(dirfd int, path string, mode uint32) (err error)
 //sys	Mkfifo(path string, mode uint32) (err error)
 //sys	Mknod(path string, mode uint32, dev int) (err error)
 //sys	Mount(fsType string, dir string, flags int, data unsafe.Pointer) (err error)
 //sys	Open(path string, mode int, perm uint32) (fd int, err error)
 //sys	Openat(dirfd int, path string, mode int, perm uint32) (fd int, err error)
 //sys	Pathconf(path string, name int) (val int, err error)
 //sys	pread(fd int, p []byte, offset int64) (n int, err 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	Renameat(fromfd int, from string, tofd int, to string) (err error)
 //sys	Revoke(path string) (err error)
 //sys	Rmdir(path string) (err error)
 //sys	Seek(fd int, offset int64, whence int) (newoffset int64, err error) = SYS_LSEEK
 //sys	Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error)
 //sys	Setattrlist(path string, attrlist *Attrlist, attrBuf []byte, options int) (err error)
 //sys	Setegid(egid int) (err error)
 //sysnb	Seteuid(euid int) (err error)
 //sysnb	Setgid(gid int) (err error)
 //sys	Setlogin(name string) (err error)
 //sysnb	Setpgid(pid int, pgid int) (err error)
 //sys	Setpriority(which int, who int, prio int) (err error)
 //sys	Setprivexec(flag int) (err error)
 //sysnb	Setregid(rgid int, egid int) (err error)
 //sysnb	Setreuid(ruid int, euid int) (err error)
 //sysnb	Setsid() (pid int, err error)
 //sysnb	Settimeofday(tp *Timeval) (err error)
 //sysnb	Setuid(uid int) (err error)
 //sys	Symlink(path string, link string) (err error)
 //sys	Symlinkat(oldpath string, newdirfd int, newpath string) (err error)
 //sys	Sync() (err error)
 //sys	Truncate(path string, length int64) (err error)
 //sys	Umask(newmask int) (oldmask int)
 //sys	Undelete(path string) (err error)
 //sys	Unlink(path string) (err error)
 //sys	Unlinkat(dirfd int, path string, flags int) (err error)
 //sys	Unmount(path string, flags int) (err error)
 //sys	write(fd int, p []byte) (n int, err error)
 //sys	mmap(addr uintptr, length uintptr, prot int, flag int, fd int, pos int64) (ret uintptr, err error)
 //sys	munmap(addr uintptr, length uintptr) (err error)
 //sys	readv(fd int, iovecs []Iovec) (n int, err error)
 //sys	preadv(fd int, iovecs []Iovec, offset int64) (n int, err error)
 //sys	writev(fd int, iovecs []Iovec) (n int, err error)
 //sys	pwritev(fd int, iovecs []Iovec, offset int64) (n int, err error)