syscall_darwin.go

  1// Copyright 2009,2010 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// Darwin system calls.
  6// This file is compiled as ordinary Go code,
  7// but it is also input to mksyscall,
  8// which parses the //sys lines and generates system call stubs.
  9// Note that sometimes we use a lowercase //sys name and wrap
 10// it in our own nicer implementation, either here or in
 11// syscall_bsd.go or syscall_unix.go.
 12
 13package unix
 14
 15import (
 16	"fmt"
 17	"syscall"
 18	"unsafe"
 19)
 20
 21//sys	closedir(dir uintptr) (err error)
 22//sys	readdir_r(dir uintptr, entry *Dirent, result **Dirent) (res Errno)
 23
 24func fdopendir(fd int) (dir uintptr, err error) {
 25	r0, _, e1 := syscall_syscallPtr(libc_fdopendir_trampoline_addr, uintptr(fd), 0, 0)
 26	dir = uintptr(r0)
 27	if e1 != 0 {
 28		err = errnoErr(e1)
 29	}
 30	return
 31}
 32
 33var libc_fdopendir_trampoline_addr uintptr
 34
 35//go:cgo_import_dynamic libc_fdopendir fdopendir "/usr/lib/libSystem.B.dylib"
 36
 37func Getdirentries(fd int, buf []byte, basep *uintptr) (n int, err error) {
 38	// Simulate Getdirentries using fdopendir/readdir_r/closedir.
 39	// We store the number of entries to skip in the seek
 40	// offset of fd. See issue #31368.
 41	// It's not the full required semantics, but should handle the case
 42	// of calling Getdirentries or ReadDirent repeatedly.
 43	// It won't handle assigning the results of lseek to *basep, or handle
 44	// the directory being edited underfoot.
 45	skip, err := Seek(fd, 0, 1 /* SEEK_CUR */)
 46	if err != nil {
 47		return 0, err
 48	}
 49
 50	// We need to duplicate the incoming file descriptor
 51	// because the caller expects to retain control of it, but
 52	// fdopendir expects to take control of its argument.
 53	// Just Dup'ing the file descriptor is not enough, as the
 54	// result shares underlying state. Use Openat to make a really
 55	// new file descriptor referring to the same directory.
 56	fd2, err := Openat(fd, ".", O_RDONLY, 0)
 57	if err != nil {
 58		return 0, err
 59	}
 60	d, err := fdopendir(fd2)
 61	if err != nil {
 62		Close(fd2)
 63		return 0, err
 64	}
 65	defer closedir(d)
 66
 67	var cnt int64
 68	for {
 69		var entry Dirent
 70		var entryp *Dirent
 71		e := readdir_r(d, &entry, &entryp)
 72		if e != 0 {
 73			return n, errnoErr(e)
 74		}
 75		if entryp == nil {
 76			break
 77		}
 78		if skip > 0 {
 79			skip--
 80			cnt++
 81			continue
 82		}
 83
 84		reclen := int(entry.Reclen)
 85		if reclen > len(buf) {
 86			// Not enough room. Return for now.
 87			// The counter will let us know where we should start up again.
 88			// Note: this strategy for suspending in the middle and
 89			// restarting is O(n^2) in the length of the directory. Oh well.
 90			break
 91		}
 92
 93		// Copy entry into return buffer.
 94		s := unsafe.Slice((*byte)(unsafe.Pointer(&entry)), reclen)
 95		copy(buf, s)
 96
 97		buf = buf[reclen:]
 98		n += reclen
 99		cnt++
100	}
101	// Set the seek offset of the input fd to record
102	// how many files we've already returned.
103	_, err = Seek(fd, cnt, 0 /* SEEK_SET */)
104	if err != nil {
105		return n, err
106	}
107
108	return n, nil
109}
110
111// SockaddrDatalink implements the Sockaddr interface for AF_LINK type sockets.
112type SockaddrDatalink struct {
113	Len    uint8
114	Family uint8
115	Index  uint16
116	Type   uint8
117	Nlen   uint8
118	Alen   uint8
119	Slen   uint8
120	Data   [12]int8
121	raw    RawSockaddrDatalink
122}
123
124// SockaddrCtl implements the Sockaddr interface for AF_SYSTEM type sockets.
125type SockaddrCtl struct {
126	ID   uint32
127	Unit uint32
128	raw  RawSockaddrCtl
129}
130
131func (sa *SockaddrCtl) sockaddr() (unsafe.Pointer, _Socklen, error) {
132	sa.raw.Sc_len = SizeofSockaddrCtl
133	sa.raw.Sc_family = AF_SYSTEM
134	sa.raw.Ss_sysaddr = AF_SYS_CONTROL
135	sa.raw.Sc_id = sa.ID
136	sa.raw.Sc_unit = sa.Unit
137	return unsafe.Pointer(&sa.raw), SizeofSockaddrCtl, nil
138}
139
140// SockaddrVM implements the Sockaddr interface for AF_VSOCK type sockets.
141// SockaddrVM provides access to Darwin VM sockets: a mechanism that enables
142// bidirectional communication between a hypervisor and its guest virtual
143// machines.
144type SockaddrVM struct {
145	// CID and Port specify a context ID and port address for a VM socket.
146	// Guests have a unique CID, and hosts may have a well-known CID of:
147	//  - VMADDR_CID_HYPERVISOR: refers to the hypervisor process.
148	//  - VMADDR_CID_LOCAL: refers to local communication (loopback).
149	//  - VMADDR_CID_HOST: refers to other processes on the host.
150	CID  uint32
151	Port uint32
152	raw  RawSockaddrVM
153}
154
155func (sa *SockaddrVM) sockaddr() (unsafe.Pointer, _Socklen, error) {
156	sa.raw.Len = SizeofSockaddrVM
157	sa.raw.Family = AF_VSOCK
158	sa.raw.Port = sa.Port
159	sa.raw.Cid = sa.CID
160
161	return unsafe.Pointer(&sa.raw), SizeofSockaddrVM, nil
162}
163
164func anyToSockaddrGOOS(fd int, rsa *RawSockaddrAny) (Sockaddr, error) {
165	switch rsa.Addr.Family {
166	case AF_SYSTEM:
167		pp := (*RawSockaddrCtl)(unsafe.Pointer(rsa))
168		if pp.Ss_sysaddr == AF_SYS_CONTROL {
169			sa := new(SockaddrCtl)
170			sa.ID = pp.Sc_id
171			sa.Unit = pp.Sc_unit
172			return sa, nil
173		}
174	case AF_VSOCK:
175		pp := (*RawSockaddrVM)(unsafe.Pointer(rsa))
176		sa := &SockaddrVM{
177			CID:  pp.Cid,
178			Port: pp.Port,
179		}
180		return sa, nil
181	}
182	return nil, EAFNOSUPPORT
183}
184
185// Some external packages rely on SYS___SYSCTL being defined to implement their
186// own sysctl wrappers. Provide it here, even though direct syscalls are no
187// longer supported on darwin.
188const SYS___SYSCTL = SYS_SYSCTL
189
190// Translate "kern.hostname" to []_C_int{0,1,2,3}.
191func nametomib(name string) (mib []_C_int, err error) {
192	const siz = unsafe.Sizeof(mib[0])
193
194	// NOTE(rsc): It seems strange to set the buffer to have
195	// size CTL_MAXNAME+2 but use only CTL_MAXNAME
196	// as the size. I don't know why the +2 is here, but the
197	// kernel uses +2 for its own implementation of this function.
198	// I am scared that if we don't include the +2 here, the kernel
199	// will silently write 2 words farther than we specify
200	// and we'll get memory corruption.
201	var buf [CTL_MAXNAME + 2]_C_int
202	n := uintptr(CTL_MAXNAME) * siz
203
204	p := (*byte)(unsafe.Pointer(&buf[0]))
205	bytes, err := ByteSliceFromString(name)
206	if err != nil {
207		return nil, err
208	}
209
210	// Magic sysctl: "setting" 0.3 to a string name
211	// lets you read back the array of integers form.
212	if err = sysctl([]_C_int{0, 3}, p, &n, &bytes[0], uintptr(len(name))); err != nil {
213		return nil, err
214	}
215	return buf[0 : n/siz], nil
216}
217
218func direntIno(buf []byte) (uint64, bool) {
219	return readInt(buf, unsafe.Offsetof(Dirent{}.Ino), unsafe.Sizeof(Dirent{}.Ino))
220}
221
222func direntReclen(buf []byte) (uint64, bool) {
223	return readInt(buf, unsafe.Offsetof(Dirent{}.Reclen), unsafe.Sizeof(Dirent{}.Reclen))
224}
225
226func direntNamlen(buf []byte) (uint64, bool) {
227	return readInt(buf, unsafe.Offsetof(Dirent{}.Namlen), unsafe.Sizeof(Dirent{}.Namlen))
228}
229
230func PtraceAttach(pid int) (err error) { return ptrace(PT_ATTACH, pid, 0, 0) }
231func PtraceDetach(pid int) (err error) { return ptrace(PT_DETACH, pid, 0, 0) }
232func PtraceDenyAttach() (err error)    { return ptrace(PT_DENY_ATTACH, 0, 0, 0) }
233
234//sysnb	pipe(p *[2]int32) (err error)
235
236func Pipe(p []int) (err error) {
237	if len(p) != 2 {
238		return EINVAL
239	}
240	var x [2]int32
241	err = pipe(&x)
242	if err == nil {
243		p[0] = int(x[0])
244		p[1] = int(x[1])
245	}
246	return
247}
248
249func Getfsstat(buf []Statfs_t, flags int) (n int, err error) {
250	var _p0 unsafe.Pointer
251	var bufsize uintptr
252	if len(buf) > 0 {
253		_p0 = unsafe.Pointer(&buf[0])
254		bufsize = unsafe.Sizeof(Statfs_t{}) * uintptr(len(buf))
255	}
256	return getfsstat(_p0, bufsize, flags)
257}
258
259func xattrPointer(dest []byte) *byte {
260	// It's only when dest is set to NULL that the OS X implementations of
261	// getxattr() and listxattr() return the current sizes of the named attributes.
262	// An empty byte array is not sufficient. To maintain the same behaviour as the
263	// linux implementation, we wrap around the system calls and pass in NULL when
264	// dest is empty.
265	var destp *byte
266	if len(dest) > 0 {
267		destp = &dest[0]
268	}
269	return destp
270}
271
272//sys	getxattr(path string, attr string, dest *byte, size int, position uint32, options int) (sz int, err error)
273
274func Getxattr(path string, attr string, dest []byte) (sz int, err error) {
275	return getxattr(path, attr, xattrPointer(dest), len(dest), 0, 0)
276}
277
278func Lgetxattr(link string, attr string, dest []byte) (sz int, err error) {
279	return getxattr(link, attr, xattrPointer(dest), len(dest), 0, XATTR_NOFOLLOW)
280}
281
282//sys	fgetxattr(fd int, attr string, dest *byte, size int, position uint32, options int) (sz int, err error)
283
284func Fgetxattr(fd int, attr string, dest []byte) (sz int, err error) {
285	return fgetxattr(fd, attr, xattrPointer(dest), len(dest), 0, 0)
286}
287
288//sys	setxattr(path string, attr string, data *byte, size int, position uint32, options int) (err error)
289
290func Setxattr(path string, attr string, data []byte, flags int) (err error) {
291	// The parameters for the OS X implementation vary slightly compared to the
292	// linux system call, specifically the position parameter:
293	//
294	//  linux:
295	//      int setxattr(
296	//          const char *path,
297	//          const char *name,
298	//          const void *value,
299	//          size_t size,
300	//          int flags
301	//      );
302	//
303	//  darwin:
304	//      int setxattr(
305	//          const char *path,
306	//          const char *name,
307	//          void *value,
308	//          size_t size,
309	//          u_int32_t position,
310	//          int options
311	//      );
312	//
313	// position specifies the offset within the extended attribute. In the
314	// current implementation, only the resource fork extended attribute makes
315	// use of this argument. For all others, position is reserved. We simply
316	// default to setting it to zero.
317	return setxattr(path, attr, xattrPointer(data), len(data), 0, flags)
318}
319
320func Lsetxattr(link string, attr string, data []byte, flags int) (err error) {
321	return setxattr(link, attr, xattrPointer(data), len(data), 0, flags|XATTR_NOFOLLOW)
322}
323
324//sys	fsetxattr(fd int, attr string, data *byte, size int, position uint32, options int) (err error)
325
326func Fsetxattr(fd int, attr string, data []byte, flags int) (err error) {
327	return fsetxattr(fd, attr, xattrPointer(data), len(data), 0, 0)
328}
329
330//sys	removexattr(path string, attr string, options int) (err error)
331
332func Removexattr(path string, attr string) (err error) {
333	// We wrap around and explicitly zero out the options provided to the OS X
334	// implementation of removexattr, we do so for interoperability with the
335	// linux variant.
336	return removexattr(path, attr, 0)
337}
338
339func Lremovexattr(link string, attr string) (err error) {
340	return removexattr(link, attr, XATTR_NOFOLLOW)
341}
342
343//sys	fremovexattr(fd int, attr string, options int) (err error)
344
345func Fremovexattr(fd int, attr string) (err error) {
346	return fremovexattr(fd, attr, 0)
347}
348
349//sys	listxattr(path string, dest *byte, size int, options int) (sz int, err error)
350
351func Listxattr(path string, dest []byte) (sz int, err error) {
352	return listxattr(path, xattrPointer(dest), len(dest), 0)
353}
354
355func Llistxattr(link string, dest []byte) (sz int, err error) {
356	return listxattr(link, xattrPointer(dest), len(dest), XATTR_NOFOLLOW)
357}
358
359//sys	flistxattr(fd int, dest *byte, size int, options int) (sz int, err error)
360
361func Flistxattr(fd int, dest []byte) (sz int, err error) {
362	return flistxattr(fd, xattrPointer(dest), len(dest), 0)
363}
364
365//sys	utimensat(dirfd int, path string, times *[2]Timespec, flags int) (err error)
366
367/*
368 * Wrapped
369 */
370
371//sys	fcntl(fd int, cmd int, arg int) (val int, err error)
372
373//sys	kill(pid int, signum int, posix int) (err error)
374
375func Kill(pid int, signum syscall.Signal) (err error) { return kill(pid, int(signum), 1) }
376
377//sys	ioctl(fd int, req uint, arg uintptr) (err error)
378//sys	ioctlPtr(fd int, req uint, arg unsafe.Pointer) (err error) = SYS_IOCTL
379
380func IoctlCtlInfo(fd int, ctlInfo *CtlInfo) error {
381	return ioctlPtr(fd, CTLIOCGINFO, unsafe.Pointer(ctlInfo))
382}
383
384// IfreqMTU is struct ifreq used to get or set a network device's MTU.
385type IfreqMTU struct {
386	Name [IFNAMSIZ]byte
387	MTU  int32
388}
389
390// IoctlGetIfreqMTU performs the SIOCGIFMTU ioctl operation on fd to get the MTU
391// of the network device specified by ifname.
392func IoctlGetIfreqMTU(fd int, ifname string) (*IfreqMTU, error) {
393	var ifreq IfreqMTU
394	copy(ifreq.Name[:], ifname)
395	err := ioctlPtr(fd, SIOCGIFMTU, unsafe.Pointer(&ifreq))
396	return &ifreq, err
397}
398
399// IoctlSetIfreqMTU performs the SIOCSIFMTU ioctl operation on fd to set the MTU
400// of the network device specified by ifreq.Name.
401func IoctlSetIfreqMTU(fd int, ifreq *IfreqMTU) error {
402	return ioctlPtr(fd, SIOCSIFMTU, unsafe.Pointer(ifreq))
403}
404
405//sys	renamexNp(from string, to string, flag uint32) (err error)
406
407func RenamexNp(from string, to string, flag uint32) (err error) {
408	return renamexNp(from, to, flag)
409}
410
411//sys	renameatxNp(fromfd int, from string, tofd int, to string, flag uint32) (err error)
412
413func RenameatxNp(fromfd int, from string, tofd int, to string, flag uint32) (err error) {
414	return renameatxNp(fromfd, from, tofd, to, flag)
415}
416
417//sys	sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error) = SYS_SYSCTL
418
419func Uname(uname *Utsname) error {
420	mib := []_C_int{CTL_KERN, KERN_OSTYPE}
421	n := unsafe.Sizeof(uname.Sysname)
422	if err := sysctl(mib, &uname.Sysname[0], &n, nil, 0); err != nil {
423		return err
424	}
425
426	mib = []_C_int{CTL_KERN, KERN_HOSTNAME}
427	n = unsafe.Sizeof(uname.Nodename)
428	if err := sysctl(mib, &uname.Nodename[0], &n, nil, 0); err != nil {
429		return err
430	}
431
432	mib = []_C_int{CTL_KERN, KERN_OSRELEASE}
433	n = unsafe.Sizeof(uname.Release)
434	if err := sysctl(mib, &uname.Release[0], &n, nil, 0); err != nil {
435		return err
436	}
437
438	mib = []_C_int{CTL_KERN, KERN_VERSION}
439	n = unsafe.Sizeof(uname.Version)
440	if err := sysctl(mib, &uname.Version[0], &n, nil, 0); err != nil {
441		return err
442	}
443
444	// The version might have newlines or tabs in it, convert them to
445	// spaces.
446	for i, b := range uname.Version {
447		if b == '\n' || b == '\t' {
448			if i == len(uname.Version)-1 {
449				uname.Version[i] = 0
450			} else {
451				uname.Version[i] = ' '
452			}
453		}
454	}
455
456	mib = []_C_int{CTL_HW, HW_MACHINE}
457	n = unsafe.Sizeof(uname.Machine)
458	if err := sysctl(mib, &uname.Machine[0], &n, nil, 0); err != nil {
459		return err
460	}
461
462	return nil
463}
464
465func Sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) {
466	if raceenabled {
467		raceReleaseMerge(unsafe.Pointer(&ioSync))
468	}
469	var length = int64(count)
470	err = sendfile(infd, outfd, *offset, &length, nil, 0)
471	written = int(length)
472	return
473}
474
475func GetsockoptIPMreqn(fd, level, opt int) (*IPMreqn, error) {
476	var value IPMreqn
477	vallen := _Socklen(SizeofIPMreqn)
478	errno := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
479	return &value, errno
480}
481
482func SetsockoptIPMreqn(fd, level, opt int, mreq *IPMreqn) (err error) {
483	return setsockopt(fd, level, opt, unsafe.Pointer(mreq), unsafe.Sizeof(*mreq))
484}
485
486// GetsockoptXucred is a getsockopt wrapper that returns an Xucred struct.
487// The usual level and opt are SOL_LOCAL and LOCAL_PEERCRED, respectively.
488func GetsockoptXucred(fd, level, opt int) (*Xucred, error) {
489	x := new(Xucred)
490	vallen := _Socklen(SizeofXucred)
491	err := getsockopt(fd, level, opt, unsafe.Pointer(x), &vallen)
492	return x, err
493}
494
495func GetsockoptTCPConnectionInfo(fd, level, opt int) (*TCPConnectionInfo, error) {
496	var value TCPConnectionInfo
497	vallen := _Socklen(SizeofTCPConnectionInfo)
498	err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
499	return &value, err
500}
501
502func SysctlKinfoProc(name string, args ...int) (*KinfoProc, error) {
503	mib, err := sysctlmib(name, args...)
504	if err != nil {
505		return nil, err
506	}
507
508	var kinfo KinfoProc
509	n := uintptr(SizeofKinfoProc)
510	if err := sysctl(mib, (*byte)(unsafe.Pointer(&kinfo)), &n, nil, 0); err != nil {
511		return nil, err
512	}
513	if n != SizeofKinfoProc {
514		return nil, EIO
515	}
516	return &kinfo, nil
517}
518
519func SysctlKinfoProcSlice(name string, args ...int) ([]KinfoProc, error) {
520	mib, err := sysctlmib(name, args...)
521	if err != nil {
522		return nil, err
523	}
524
525	for {
526		// Find size.
527		n := uintptr(0)
528		if err := sysctl(mib, nil, &n, nil, 0); err != nil {
529			return nil, err
530		}
531		if n == 0 {
532			return nil, nil
533		}
534		if n%SizeofKinfoProc != 0 {
535			return nil, fmt.Errorf("sysctl() returned a size of %d, which is not a multiple of %d", n, SizeofKinfoProc)
536		}
537
538		// Read into buffer of that size.
539		buf := make([]KinfoProc, n/SizeofKinfoProc)
540		if err := sysctl(mib, (*byte)(unsafe.Pointer(&buf[0])), &n, nil, 0); err != nil {
541			if err == ENOMEM {
542				// Process table grew. Try again.
543				continue
544			}
545			return nil, err
546		}
547		if n%SizeofKinfoProc != 0 {
548			return nil, fmt.Errorf("sysctl() returned a size of %d, which is not a multiple of %d", n, SizeofKinfoProc)
549		}
550
551		// The actual call may return less than the original reported required
552		// size so ensure we deal with that.
553		return buf[:n/SizeofKinfoProc], nil
554	}
555}
556
557//sys	pthread_chdir_np(path string) (err error)
558
559func PthreadChdir(path string) (err error) {
560	return pthread_chdir_np(path)
561}
562
563//sys	pthread_fchdir_np(fd int) (err error)
564
565func PthreadFchdir(fd int) (err error) {
566	return pthread_fchdir_np(fd)
567}
568
569// Connectx calls connectx(2) to initiate a connection on a socket.
570//
571// srcIf, srcAddr, and dstAddr are filled into a [SaEndpoints] struct and passed as the endpoints argument.
572//
573//   - srcIf is the optional source interface index. 0 means unspecified.
574//   - srcAddr is the optional source address. nil means unspecified.
575//   - dstAddr is the destination address.
576//
577// On success, Connectx returns the number of bytes enqueued for transmission.
578func Connectx(fd int, srcIf uint32, srcAddr, dstAddr Sockaddr, associd SaeAssocID, flags uint32, iov []Iovec, connid *SaeConnID) (n uintptr, err error) {
579	endpoints := SaEndpoints{
580		Srcif: srcIf,
581	}
582
583	if srcAddr != nil {
584		addrp, addrlen, err := srcAddr.sockaddr()
585		if err != nil {
586			return 0, err
587		}
588		endpoints.Srcaddr = (*RawSockaddr)(addrp)
589		endpoints.Srcaddrlen = uint32(addrlen)
590	}
591
592	if dstAddr != nil {
593		addrp, addrlen, err := dstAddr.sockaddr()
594		if err != nil {
595			return 0, err
596		}
597		endpoints.Dstaddr = (*RawSockaddr)(addrp)
598		endpoints.Dstaddrlen = uint32(addrlen)
599	}
600
601	err = connectx(fd, &endpoints, associd, flags, iov, &n, connid)
602	return
603}
604
605// sys	connectx(fd int, endpoints *SaEndpoints, associd SaeAssocID, flags uint32, iov []Iovec, n *uintptr, connid *SaeConnID) (err error)
606const minIovec = 8
607
608func Readv(fd int, iovs [][]byte) (n int, err error) {
609	if !darwinKernelVersionMin(11, 0, 0) {
610		return 0, ENOSYS
611	}
612
613	iovecs := make([]Iovec, 0, minIovec)
614	iovecs = appendBytes(iovecs, iovs)
615	n, err = readv(fd, iovecs)
616	readvRacedetect(iovecs, n, err)
617	return n, err
618}
619
620func Preadv(fd int, iovs [][]byte, offset int64) (n int, err error) {
621	if !darwinKernelVersionMin(11, 0, 0) {
622		return 0, ENOSYS
623	}
624	iovecs := make([]Iovec, 0, minIovec)
625	iovecs = appendBytes(iovecs, iovs)
626	n, err = preadv(fd, iovecs, offset)
627	readvRacedetect(iovecs, n, err)
628	return n, err
629}
630
631func Writev(fd int, iovs [][]byte) (n int, err error) {
632	if !darwinKernelVersionMin(11, 0, 0) {
633		return 0, ENOSYS
634	}
635
636	iovecs := make([]Iovec, 0, minIovec)
637	iovecs = appendBytes(iovecs, iovs)
638	if raceenabled {
639		raceReleaseMerge(unsafe.Pointer(&ioSync))
640	}
641	n, err = writev(fd, iovecs)
642	writevRacedetect(iovecs, n)
643	return n, err
644}
645
646func Pwritev(fd int, iovs [][]byte, offset int64) (n int, err error) {
647	if !darwinKernelVersionMin(11, 0, 0) {
648		return 0, ENOSYS
649	}
650
651	iovecs := make([]Iovec, 0, minIovec)
652	iovecs = appendBytes(iovecs, iovs)
653	if raceenabled {
654		raceReleaseMerge(unsafe.Pointer(&ioSync))
655	}
656	n, err = pwritev(fd, iovecs, offset)
657	writevRacedetect(iovecs, n)
658	return n, err
659}
660
661func appendBytes(vecs []Iovec, bs [][]byte) []Iovec {
662	for _, b := range bs {
663		var v Iovec
664		v.SetLen(len(b))
665		if len(b) > 0 {
666			v.Base = &b[0]
667		} else {
668			v.Base = (*byte)(unsafe.Pointer(&_zero))
669		}
670		vecs = append(vecs, v)
671	}
672	return vecs
673}
674
675func writevRacedetect(iovecs []Iovec, n int) {
676	if !raceenabled {
677		return
678	}
679	for i := 0; n > 0 && i < len(iovecs); i++ {
680		m := int(iovecs[i].Len)
681		if m > n {
682			m = n
683		}
684		n -= m
685		if m > 0 {
686			raceReadRange(unsafe.Pointer(iovecs[i].Base), m)
687		}
688	}
689}
690
691func readvRacedetect(iovecs []Iovec, n int, err error) {
692	if !raceenabled {
693		return
694	}
695	for i := 0; n > 0 && i < len(iovecs); i++ {
696		m := int(iovecs[i].Len)
697		if m > n {
698			m = n
699		}
700		n -= m
701		if m > 0 {
702			raceWriteRange(unsafe.Pointer(iovecs[i].Base), m)
703		}
704	}
705	if err == nil {
706		raceAcquire(unsafe.Pointer(&ioSync))
707	}
708}
709
710func darwinMajorMinPatch() (maj, min, patch int, err error) {
711	var un Utsname
712	err = Uname(&un)
713	if err != nil {
714		return
715	}
716
717	var mmp [3]int
718	c := 0
719Loop:
720	for _, b := range un.Release[:] {
721		switch {
722		case b >= '0' && b <= '9':
723			mmp[c] = 10*mmp[c] + int(b-'0')
724		case b == '.':
725			c++
726			if c > 2 {
727				return 0, 0, 0, ENOTSUP
728			}
729		case b == 0:
730			break Loop
731		default:
732			return 0, 0, 0, ENOTSUP
733		}
734	}
735	if c != 2 {
736		return 0, 0, 0, ENOTSUP
737	}
738	return mmp[0], mmp[1], mmp[2], nil
739}
740
741func darwinKernelVersionMin(maj, min, patch int) bool {
742	actualMaj, actualMin, actualPatch, err := darwinMajorMinPatch()
743	if err != nil {
744		return false
745	}
746	return actualMaj > maj || actualMaj == maj && (actualMin > min || actualMin == min && actualPatch >= patch)
747}
748
749//sys	sendfile(infd int, outfd int, offset int64, len *int64, hdtr unsafe.Pointer, flags int) (err error)
750
751//sys	shmat(id int, addr uintptr, flag int) (ret uintptr, err error)
752//sys	shmctl(id int, cmd int, buf *SysvShmDesc) (result int, err error)
753//sys	shmdt(addr uintptr) (err error)
754//sys	shmget(key int, size int, flag int) (id int, err error)
755
756/*
757 * Exposed directly
758 */
759//sys	Access(path string, mode uint32) (err error)
760//sys	Adjtime(delta *Timeval, olddelta *Timeval) (err error)
761//sys	Chdir(path string) (err error)
762//sys	Chflags(path string, flags int) (err error)
763//sys	Chmod(path string, mode uint32) (err error)
764//sys	Chown(path string, uid int, gid int) (err error)
765//sys	Chroot(path string) (err error)
766//sys	ClockGettime(clockid int32, time *Timespec) (err error)
767//sys	Close(fd int) (err error)
768//sys	Clonefile(src string, dst string, flags int) (err error)
769//sys	Clonefileat(srcDirfd int, src string, dstDirfd int, dst string, flags int) (err error)
770//sys	Dup(fd int) (nfd int, err error)
771//sys	Dup2(from int, to int) (err error)
772//sys	Exchangedata(path1 string, path2 string, options int) (err error)
773//sys	Exit(code int)
774//sys	Faccessat(dirfd int, path string, mode uint32, flags int) (err error)
775//sys	Fchdir(fd int) (err error)
776//sys	Fchflags(fd int, flags int) (err error)
777//sys	Fchmod(fd int, mode uint32) (err error)
778//sys	Fchmodat(dirfd int, path string, mode uint32, flags int) (err error)
779//sys	Fchown(fd int, uid int, gid int) (err error)
780//sys	Fchownat(dirfd int, path string, uid int, gid int, flags int) (err error)
781//sys	Fclonefileat(srcDirfd int, dstDirfd int, dst string, flags int) (err error)
782//sys	Flock(fd int, how int) (err error)
783//sys	Fpathconf(fd int, name int) (val int, err error)
784//sys	Fsync(fd int) (err error)
785//sys	Ftruncate(fd int, length int64) (err error)
786//sys	Getcwd(buf []byte) (n int, err error)
787//sys	Getdtablesize() (size int)
788//sysnb	Getegid() (egid int)
789//sysnb	Geteuid() (uid int)
790//sysnb	Getgid() (gid int)
791//sysnb	Getpgid(pid int) (pgid int, err error)
792//sysnb	Getpgrp() (pgrp int)
793//sysnb	Getpid() (pid int)
794//sysnb	Getppid() (ppid int)
795//sys	Getpriority(which int, who int) (prio int, err error)
796//sysnb	Getrlimit(which int, lim *Rlimit) (err error)
797//sysnb	Getrusage(who int, rusage *Rusage) (err error)
798//sysnb	Getsid(pid int) (sid int, err error)
799//sysnb	Gettimeofday(tp *Timeval) (err error)
800//sysnb	Getuid() (uid int)
801//sysnb	Issetugid() (tainted bool)
802//sys	Kqueue() (fd int, err error)
803//sys	Lchown(path string, uid int, gid int) (err error)
804//sys	Link(path string, link string) (err error)
805//sys	Linkat(pathfd int, path string, linkfd int, link string, flags int) (err error)
806//sys	Listen(s int, backlog int) (err error)
807//sys	Mkdir(path string, mode uint32) (err error)
808//sys	Mkdirat(dirfd int, path string, mode uint32) (err error)
809//sys	Mkfifo(path string, mode uint32) (err error)
810//sys	Mknod(path string, mode uint32, dev int) (err error)
811//sys	Mount(fsType string, dir string, flags int, data unsafe.Pointer) (err error)
812//sys	Open(path string, mode int, perm uint32) (fd int, err error)
813//sys	Openat(dirfd int, path string, mode int, perm uint32) (fd int, err error)
814//sys	Pathconf(path string, name int) (val int, err error)
815//sys	pread(fd int, p []byte, offset int64) (n int, err error)
816//sys	pwrite(fd int, p []byte, offset int64) (n int, err error)
817//sys	read(fd int, p []byte) (n int, err error)
818//sys	Readlink(path string, buf []byte) (n int, err error)
819//sys	Readlinkat(dirfd int, path string, buf []byte) (n int, err error)
820//sys	Rename(from string, to string) (err error)
821//sys	Renameat(fromfd int, from string, tofd int, to string) (err error)
822//sys	Revoke(path string) (err error)
823//sys	Rmdir(path string) (err error)
824//sys	Seek(fd int, offset int64, whence int) (newoffset int64, err error) = SYS_LSEEK
825//sys	Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error)
826//sys	Setattrlist(path string, attrlist *Attrlist, attrBuf []byte, options int) (err error)
827//sys	Setegid(egid int) (err error)
828//sysnb	Seteuid(euid int) (err error)
829//sysnb	Setgid(gid int) (err error)
830//sys	Setlogin(name string) (err error)
831//sysnb	Setpgid(pid int, pgid int) (err error)
832//sys	Setpriority(which int, who int, prio int) (err error)
833//sys	Setprivexec(flag int) (err error)
834//sysnb	Setregid(rgid int, egid int) (err error)
835//sysnb	Setreuid(ruid int, euid int) (err error)
836//sysnb	Setsid() (pid int, err error)
837//sysnb	Settimeofday(tp *Timeval) (err error)
838//sysnb	Setuid(uid int) (err error)
839//sys	Symlink(path string, link string) (err error)
840//sys	Symlinkat(oldpath string, newdirfd int, newpath string) (err error)
841//sys	Sync() (err error)
842//sys	Truncate(path string, length int64) (err error)
843//sys	Umask(newmask int) (oldmask int)
844//sys	Undelete(path string) (err error)
845//sys	Unlink(path string) (err error)
846//sys	Unlinkat(dirfd int, path string, flags int) (err error)
847//sys	Unmount(path string, flags int) (err error)
848//sys	write(fd int, p []byte) (n int, err error)
849//sys	mmap(addr uintptr, length uintptr, prot int, flag int, fd int, pos int64) (ret uintptr, err error)
850//sys	munmap(addr uintptr, length uintptr) (err error)
851//sys	readv(fd int, iovecs []Iovec) (n int, err error)
852//sys	preadv(fd int, iovecs []Iovec, offset int64) (n int, err error)
853//sys	writev(fd int, iovecs []Iovec) (n int, err error)
854//sys	pwritev(fd int, iovecs []Iovec, offset int64) (n int, err error)