text: // 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 (
  	"errors"
  	"syscall"
  	"unsafe"
  )
  
  const ImplementsGetwd = true
  
  func Getwd() (string, error) {
  	buf := make([]byte, 2048)
  	attrs, err := getAttrList(".", attrList{CommonAttr: attrCmnFullpath}, buf, 0)
  	if err == nil && len(attrs) == 1 && len(attrs[0]) >= 2 {
  		wd := string(attrs[0])
  		// Sanity check that it's an absolute path and ends
  		// in a null byte, which we then strip.
  		if wd[0] == '/' && wd[len(wd)-1] == 0 {
  			return wd[:len(wd)-1], nil
  		}
  	}
  	// If pkg/os/getwd.go gets ENOTSUP, it will fall back to the
  	// slow algorithm.
  	return "", ENOTSUP
  }
  
  // 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
  }
  
  // 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) }
  
  const (
  	attrBitMapCount = 5
  	attrCmnFullpath = 0x08000000
  )
  
  type attrList struct {
  	bitmapCount uint16
  	_           uint16
  	CommonAttr  uint32
  	VolAttr     uint32
  	DirAttr     uint32
  	FileAttr    uint32
  	Forkattr    uint32
  }
  
  func getAttrList(path string, attrList attrList, attrBuf []byte, options uint) (attrs [][]byte, err error) {
  	if len(attrBuf) < 4 {
  		return nil, errors.New("attrBuf too small")
  	}
  	attrList.bitmapCount = attrBitMapCount
  
  	var _p0 *byte
  	_p0, err = BytePtrFromString(path)
  	if err != nil {
  		return nil, err
  	}
  
  	if err := getattrlist(_p0, unsafe.Pointer(&attrList), unsafe.Pointer(&attrBuf[0]), uintptr(len(attrBuf)), int(options)); err != nil {
  		return nil, err
  	}
  	size := *(*uint32)(unsafe.Pointer(&attrBuf[0]))
  
  	// dat is the section of attrBuf that contains valid data,
  	// without the 4 byte length header. All attribute offsets
  	// are relative to dat.
  	dat := attrBuf
  	if int(size) < len(attrBuf) {
  		dat = dat[:size]
  	}
  	dat = dat[4:] // remove length prefix
  
  	for i := uint32(0); int(i) < len(dat); {
  		header := dat[i:]
  		if len(header) < 8 {
  			return attrs, errors.New("truncated attribute header")
  		}
  		datOff := *(*int32)(unsafe.Pointer(&header[0]))
  		attrLen := *(*uint32)(unsafe.Pointer(&header[4]))
  		if datOff < 0 || uint32(datOff)+attrLen > uint32(len(dat)) {
  			return attrs, errors.New("truncated results; attrBuf too small")
  		}
  		end := uint32(datOff) + attrLen
  		attrs = append(attrs, dat[datOff:end])
  		i = end
  		if r := i % 4; r != 0 {
  			i += (4 - r)
  		}
  	}
  	return
  }
  
  //sys getattrlist(path *byte, list unsafe.Pointer, buf unsafe.Pointer, size uintptr, options int) (err error)
  
  //sysnb pipe() (r int, w int, err error)
  
  func Pipe(p []int) (err error) {
  	if len(p) != 2 {
  		return EINVAL
  	}
  	p[0], p[1], err = pipe()
  	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)
  }
  
  func setattrlistTimes(path string, times []Timespec, flags int) error {
  	_p0, err := BytePtrFromString(path)
  	if err != nil {
  		return err
  	}
  
  	var attrList attrList
  	attrList.bitmapCount = ATTR_BIT_MAP_COUNT
  	attrList.CommonAttr = ATTR_CMN_MODTIME | ATTR_CMN_ACCTIME
  
  	// order is mtime, atime: the opposite of Chtimes
  	attributes := [2]Timespec{times[1], times[0]}
  	options := 0
  	if flags&AT_SYMLINK_NOFOLLOW != 0 {
  		options |= FSOPT_NOFOLLOW
  	}
  	return setattrlist(
  		_p0,
  		unsafe.Pointer(&attrList),
  		unsafe.Pointer(&attributes),
  		unsafe.Sizeof(attributes),
  		options)
  }
  
  //sys setattrlist(path *byte, list unsafe.Pointer, buf unsafe.Pointer, size uintptr, options int) (err error)
  
  func utimensat(dirfd int, path string, times *[2]Timespec, flags int) error {
  	// Darwin doesn't support SYS_UTIMENSAT
  	return ENOSYS
  }
  
  /*
   * 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   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
  }
  
  //sys	sendfile(infd int, outfd int, offset int64, len *int64, hdtr unsafe.Pointer, flags 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	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	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	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	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	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	Setrlimit(which int, lim *Rlimit) (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	readlen(fd int, buf *byte, nbuf int) (n int, err error) = SYS_READ
  //sys	writelen(fd int, buf *byte, nbuf int) (n int, err error) = SYS_WRITE
  
  /*
   * Unimplemented
   */
  // Profil
  // Sigaction
  // Sigprocmask
  // Getlogin
  // Sigpending
  // Sigaltstack
  // Ioctl
  // Reboot
  // Execve
  // Vfork
  // Sbrk
  // Sstk
  // Ovadvise
  // Mincore
  // Setitimer
  // Swapon
  // Select
  // Sigsuspend
  // Readv
  // Writev
  // Nfssvc
  // Getfh
  // Quotactl
  // Mount
  // Csops
  // Waitid
  // Add_profil
  // Kdebug_trace
  // Sigreturn
  // Atsocket
  // Kqueue_from_portset_np
  // Kqueue_portset
  // Getattrlist
  // Setattrlist
  // Getdirentriesattr
  // Searchfs
  // Delete
  // Copyfile
  // Watchevent
  // Waitevent
  // Modwatch
  // Fsctl
  // Initgroups
  // Posix_spawn
  // Nfsclnt
  // Fhopen
  // Minherit
  // Semsys
  // Msgsys
  // Shmsys
  // Semctl
  // Semget
  // Semop
  // Msgctl
  // Msgget
  // Msgsnd
  // Msgrcv
  // Shmat
  // Shmctl
  // Shmdt
  // Shmget
  // Shm_open
  // Shm_unlink
  // Sem_open
  // Sem_close
  // Sem_unlink
  // Sem_wait
  // Sem_trywait
  // Sem_post
  // Sem_getvalue
  // Sem_init
  // Sem_destroy
  // Open_extended
  // Umask_extended
  // Stat_extended
  // Lstat_extended
  // Fstat_extended
  // Chmod_extended
  // Fchmod_extended
  // Access_extended
  // Settid
  // Gettid
  // Setsgroups
  // Getsgroups
  // Setwgroups
  // Getwgroups
  // Mkfifo_extended
  // Mkdir_extended
  // Identitysvc
  // Shared_region_check_np
  // Shared_region_map_np
  // __pthread_mutex_destroy
  // __pthread_mutex_init
  // __pthread_mutex_lock
  // __pthread_mutex_trylock
  // __pthread_mutex_unlock
  // __pthread_cond_init
  // __pthread_cond_destroy
  // __pthread_cond_broadcast
  // __pthread_cond_signal
  // Setsid_with_pid
  // __pthread_cond_timedwait
  // Aio_fsync
  // Aio_return
  // Aio_suspend
  // Aio_cancel
  // Aio_error
  // Aio_read
  // Aio_write
  // Lio_listio
  // __pthread_cond_wait
  // Iopolicysys
  // __pthread_kill
  // __pthread_sigmask
  // __sigwait
  // __disable_threadsignal
  // __pthread_markcancel
  // __pthread_canceled
  // __semwait_signal
  // Proc_info
  // sendfile
  // Stat64_extended
  // Lstat64_extended
  // Fstat64_extended
  // __pthread_chdir
  // __pthread_fchdir
  // Audit
  // Auditon
  // Getauid
  // Setauid
  // Getaudit
  // Setaudit
  // Getaudit_addr
  // Setaudit_addr
  // Auditctl
  // Bsdthread_create
  // Bsdthread_terminate
  // Stack_snapshot
  // Bsdthread_register
  // Workq_open
  // Workq_ops
  // __mac_execve
  // __mac_syscall
  // __mac_get_file
  // __mac_set_file
  // __mac_get_link
  // __mac_set_link
  // __mac_get_proc
  // __mac_set_proc
  // __mac_get_fd
  // __mac_set_fd
  // __mac_get_pid
  // __mac_get_lcid
  // __mac_get_lctx
  // __mac_set_lctx
  // Setlcid
  // Read_nocancel
  // Write_nocancel
  // Open_nocancel
  // Close_nocancel
  // Wait4_nocancel
  // Recvmsg_nocancel
  // Sendmsg_nocancel
  // Recvfrom_nocancel
  // Accept_nocancel
  // Fcntl_nocancel
  // Select_nocancel
  // Fsync_nocancel
  // Connect_nocancel
  // Sigsuspend_nocancel
  // Readv_nocancel
  // Writev_nocancel
  // Sendto_nocancel
  // Pread_nocancel
  // Pwrite_nocancel
  // Waitid_nocancel
  // Poll_nocancel
  // Msgsnd_nocancel
  // Msgrcv_nocancel
  // Sem_wait_nocancel
  // Aio_suspend_nocancel
  // __sigwait_nocancel
  // __semwait_signal_nocancel
  // __mac_mount
  // __mac_get_mount
  // __mac_getfsstat
  