github.com/reiver/go@v0.0.0-20150109200633-1d0c7792f172/src/syscall/syscall_windows.go (about)

     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  // Windows system calls.
     6  
     7  package syscall
     8  
     9  import (
    10  	errorspkg "errors"
    11  	"sync"
    12  	"unicode/utf16"
    13  	"unsafe"
    14  )
    15  
    16  //go:generate go run mksyscall_windows.go -output zsyscall_windows.go syscall_windows.go security_windows.go
    17  
    18  type Handle uintptr
    19  
    20  const InvalidHandle = ^Handle(0)
    21  
    22  // StringToUTF16 is deprecated. Use UTF16FromString instead.
    23  // If s contains a NUL byte this function panics instead of
    24  // returning an error.
    25  func StringToUTF16(s string) []uint16 {
    26  	a, err := UTF16FromString(s)
    27  	if err != nil {
    28  		panic("syscall: string with NUL passed to StringToUTF16")
    29  	}
    30  	return a
    31  }
    32  
    33  // UTF16FromString returns the UTF-16 encoding of the UTF-8 string
    34  // s, with a terminating NUL added. If s contains a NUL byte at any
    35  // location, it returns (nil, EINVAL).
    36  func UTF16FromString(s string) ([]uint16, error) {
    37  	for i := 0; i < len(s); i++ {
    38  		if s[i] == 0 {
    39  			return nil, EINVAL
    40  		}
    41  	}
    42  	return utf16.Encode([]rune(s + "\x00")), nil
    43  }
    44  
    45  // UTF16ToString returns the UTF-8 encoding of the UTF-16 sequence s,
    46  // with a terminating NUL removed.
    47  func UTF16ToString(s []uint16) string {
    48  	for i, v := range s {
    49  		if v == 0 {
    50  			s = s[0:i]
    51  			break
    52  		}
    53  	}
    54  	return string(utf16.Decode(s))
    55  }
    56  
    57  // StringToUTF16Ptr is deprecated. Use UTF16PtrFromString instead.
    58  // If s contains a NUL byte this function panics instead of
    59  // returning an error.
    60  func StringToUTF16Ptr(s string) *uint16 { return &StringToUTF16(s)[0] }
    61  
    62  // UTF16PtrFromString returns pointer to the UTF-16 encoding of
    63  // the UTF-8 string s, with a terminating NUL added. If s
    64  // contains a NUL byte at any location, it returns (nil, EINVAL).
    65  func UTF16PtrFromString(s string) (*uint16, error) {
    66  	a, err := UTF16FromString(s)
    67  	if err != nil {
    68  		return nil, err
    69  	}
    70  	return &a[0], nil
    71  }
    72  
    73  func Getpagesize() int { return 4096 }
    74  
    75  // Errno is the Windows error number.
    76  type Errno uintptr
    77  
    78  func langid(pri, sub uint16) uint32 { return uint32(sub)<<10 | uint32(pri) }
    79  
    80  func (e Errno) Error() string {
    81  	// deal with special go errors
    82  	idx := int(e - APPLICATION_ERROR)
    83  	if 0 <= idx && idx < len(errors) {
    84  		return errors[idx]
    85  	}
    86  	// ask windows for the remaining errors
    87  	var flags uint32 = FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ARGUMENT_ARRAY | FORMAT_MESSAGE_IGNORE_INSERTS
    88  	b := make([]uint16, 300)
    89  	n, err := FormatMessage(flags, 0, uint32(e), langid(LANG_ENGLISH, SUBLANG_ENGLISH_US), b, nil)
    90  	if err != nil {
    91  		n, err = FormatMessage(flags, 0, uint32(e), 0, b, nil)
    92  		if err != nil {
    93  			return "winapi error #" + itoa(int(e))
    94  		}
    95  	}
    96  	// trim terminating \r and \n
    97  	for ; n > 0 && (b[n-1] == '\n' || b[n-1] == '\r'); n-- {
    98  	}
    99  	return string(utf16.Decode(b[:n]))
   100  }
   101  
   102  func (e Errno) Temporary() bool {
   103  	return e == EINTR || e == EMFILE || e.Timeout()
   104  }
   105  
   106  func (e Errno) Timeout() bool {
   107  	return e == EAGAIN || e == EWOULDBLOCK || e == ETIMEDOUT
   108  }
   109  
   110  // Implemented in asm_windows.s
   111  func compileCallback(fn interface{}, cleanstack bool) uintptr
   112  
   113  // Converts a Go function to a function pointer conforming
   114  // to the stdcall calling convention. This is useful when
   115  // interoperating with Windows code requiring callbacks.
   116  func NewCallback(fn interface{}) uintptr {
   117  	return compileCallback(fn, true)
   118  }
   119  
   120  // Converts a Go function to a function pointer conforming
   121  // to the cdecl calling convention. This is useful when
   122  // interoperating with Windows code requiring callbacks.
   123  func NewCallbackCDecl(fn interface{}) uintptr {
   124  	return compileCallback(fn, false)
   125  }
   126  
   127  // windows api calls
   128  
   129  //sys	GetLastError() (lasterr error)
   130  //sys	LoadLibrary(libname string) (handle Handle, err error) = LoadLibraryW
   131  //sys	FreeLibrary(handle Handle) (err error)
   132  //sys	GetProcAddress(module Handle, procname string) (proc uintptr, err error)
   133  //sys	GetVersion() (ver uint32, err error)
   134  //sys	FormatMessage(flags uint32, msgsrc uint32, msgid uint32, langid uint32, buf []uint16, args *byte) (n uint32, err error) = FormatMessageW
   135  //sys	ExitProcess(exitcode uint32)
   136  //sys	CreateFile(name *uint16, access uint32, mode uint32, sa *SecurityAttributes, createmode uint32, attrs uint32, templatefile int32) (handle Handle, err error) [failretval==InvalidHandle] = CreateFileW
   137  //sys	ReadFile(handle Handle, buf []byte, done *uint32, overlapped *Overlapped) (err error)
   138  //sys	WriteFile(handle Handle, buf []byte, done *uint32, overlapped *Overlapped) (err error)
   139  //sys	SetFilePointer(handle Handle, lowoffset int32, highoffsetptr *int32, whence uint32) (newlowoffset uint32, err error) [failretval==0xffffffff]
   140  //sys	CloseHandle(handle Handle) (err error)
   141  //sys	GetStdHandle(stdhandle int) (handle Handle, err error) [failretval==InvalidHandle]
   142  //sys	findFirstFile1(name *uint16, data *win32finddata1) (handle Handle, err error) [failretval==InvalidHandle] = FindFirstFileW
   143  //sys	findNextFile1(handle Handle, data *win32finddata1) (err error) = FindNextFileW
   144  //sys	FindClose(handle Handle) (err error)
   145  //sys	GetFileInformationByHandle(handle Handle, data *ByHandleFileInformation) (err error)
   146  //sys	GetCurrentDirectory(buflen uint32, buf *uint16) (n uint32, err error) = GetCurrentDirectoryW
   147  //sys	SetCurrentDirectory(path *uint16) (err error) = SetCurrentDirectoryW
   148  //sys	CreateDirectory(path *uint16, sa *SecurityAttributes) (err error) = CreateDirectoryW
   149  //sys	RemoveDirectory(path *uint16) (err error) = RemoveDirectoryW
   150  //sys	DeleteFile(path *uint16) (err error) = DeleteFileW
   151  //sys	MoveFile(from *uint16, to *uint16) (err error) = MoveFileW
   152  //sys	GetComputerName(buf *uint16, n *uint32) (err error) = GetComputerNameW
   153  //sys	SetEndOfFile(handle Handle) (err error)
   154  //sys	GetSystemTimeAsFileTime(time *Filetime)
   155  //sys	GetTimeZoneInformation(tzi *Timezoneinformation) (rc uint32, err error) [failretval==0xffffffff]
   156  //sys	CreateIoCompletionPort(filehandle Handle, cphandle Handle, key uint32, threadcnt uint32) (handle Handle, err error)
   157  //sys	GetQueuedCompletionStatus(cphandle Handle, qty *uint32, key *uint32, overlapped **Overlapped, timeout uint32) (err error)
   158  //sys	PostQueuedCompletionStatus(cphandle Handle, qty uint32, key uint32, overlapped *Overlapped) (err error)
   159  //sys	CancelIo(s Handle) (err error)
   160  //sys	CancelIoEx(s Handle, o *Overlapped) (err error)
   161  //sys	CreateProcess(appName *uint16, commandLine *uint16, procSecurity *SecurityAttributes, threadSecurity *SecurityAttributes, inheritHandles bool, creationFlags uint32, env *uint16, currentDir *uint16, startupInfo *StartupInfo, outProcInfo *ProcessInformation) (err error) = CreateProcessW
   162  //sys	OpenProcess(da uint32, inheritHandle bool, pid uint32) (handle Handle, err error)
   163  //sys	TerminateProcess(handle Handle, exitcode uint32) (err error)
   164  //sys	GetExitCodeProcess(handle Handle, exitcode *uint32) (err error)
   165  //sys	GetStartupInfo(startupInfo *StartupInfo) (err error) = GetStartupInfoW
   166  //sys	GetCurrentProcess() (pseudoHandle Handle, err error)
   167  //sys	GetProcessTimes(handle Handle, creationTime *Filetime, exitTime *Filetime, kernelTime *Filetime, userTime *Filetime) (err error)
   168  //sys	DuplicateHandle(hSourceProcessHandle Handle, hSourceHandle Handle, hTargetProcessHandle Handle, lpTargetHandle *Handle, dwDesiredAccess uint32, bInheritHandle bool, dwOptions uint32) (err error)
   169  //sys	WaitForSingleObject(handle Handle, waitMilliseconds uint32) (event uint32, err error) [failretval==0xffffffff]
   170  //sys	GetTempPath(buflen uint32, buf *uint16) (n uint32, err error) = GetTempPathW
   171  //sys	CreatePipe(readhandle *Handle, writehandle *Handle, sa *SecurityAttributes, size uint32) (err error)
   172  //sys	GetFileType(filehandle Handle) (n uint32, err error)
   173  //sys	CryptAcquireContext(provhandle *Handle, container *uint16, provider *uint16, provtype uint32, flags uint32) (err error) = advapi32.CryptAcquireContextW
   174  //sys	CryptReleaseContext(provhandle Handle, flags uint32) (err error) = advapi32.CryptReleaseContext
   175  //sys	CryptGenRandom(provhandle Handle, buflen uint32, buf *byte) (err error) = advapi32.CryptGenRandom
   176  //sys	GetEnvironmentStrings() (envs *uint16, err error) [failretval==nil] = kernel32.GetEnvironmentStringsW
   177  //sys	FreeEnvironmentStrings(envs *uint16) (err error) = kernel32.FreeEnvironmentStringsW
   178  //sys	GetEnvironmentVariable(name *uint16, buffer *uint16, size uint32) (n uint32, err error) = kernel32.GetEnvironmentVariableW
   179  //sys	SetEnvironmentVariable(name *uint16, value *uint16) (err error) = kernel32.SetEnvironmentVariableW
   180  //sys	SetFileTime(handle Handle, ctime *Filetime, atime *Filetime, wtime *Filetime) (err error)
   181  //sys	GetFileAttributes(name *uint16) (attrs uint32, err error) [failretval==INVALID_FILE_ATTRIBUTES] = kernel32.GetFileAttributesW
   182  //sys	SetFileAttributes(name *uint16, attrs uint32) (err error) = kernel32.SetFileAttributesW
   183  //sys	GetFileAttributesEx(name *uint16, level uint32, info *byte) (err error) = kernel32.GetFileAttributesExW
   184  //sys	GetCommandLine() (cmd *uint16) = kernel32.GetCommandLineW
   185  //sys	CommandLineToArgv(cmd *uint16, argc *int32) (argv *[8192]*[8192]uint16, err error) [failretval==nil] = shell32.CommandLineToArgvW
   186  //sys	LocalFree(hmem Handle) (handle Handle, err error) [failretval!=0]
   187  //sys	SetHandleInformation(handle Handle, mask uint32, flags uint32) (err error)
   188  //sys	FlushFileBuffers(handle Handle) (err error)
   189  //sys	GetFullPathName(path *uint16, buflen uint32, buf *uint16, fname **uint16) (n uint32, err error) = kernel32.GetFullPathNameW
   190  //sys	GetLongPathName(path *uint16, buf *uint16, buflen uint32) (n uint32, err error) = kernel32.GetLongPathNameW
   191  //sys	GetShortPathName(longpath *uint16, shortpath *uint16, buflen uint32) (n uint32, err error) = kernel32.GetShortPathNameW
   192  //sys	CreateFileMapping(fhandle Handle, sa *SecurityAttributes, prot uint32, maxSizeHigh uint32, maxSizeLow uint32, name *uint16) (handle Handle, err error) = kernel32.CreateFileMappingW
   193  //sys	MapViewOfFile(handle Handle, access uint32, offsetHigh uint32, offsetLow uint32, length uintptr) (addr uintptr, err error)
   194  //sys	UnmapViewOfFile(addr uintptr) (err error)
   195  //sys	FlushViewOfFile(addr uintptr, length uintptr) (err error)
   196  //sys	VirtualLock(addr uintptr, length uintptr) (err error)
   197  //sys	VirtualUnlock(addr uintptr, length uintptr) (err error)
   198  //sys	TransmitFile(s Handle, handle Handle, bytesToWrite uint32, bytsPerSend uint32, overlapped *Overlapped, transmitFileBuf *TransmitFileBuffers, flags uint32) (err error) = mswsock.TransmitFile
   199  //sys	ReadDirectoryChanges(handle Handle, buf *byte, buflen uint32, watchSubTree bool, mask uint32, retlen *uint32, overlapped *Overlapped, completionRoutine uintptr) (err error) = kernel32.ReadDirectoryChangesW
   200  //sys	CertOpenSystemStore(hprov Handle, name *uint16) (store Handle, err error) = crypt32.CertOpenSystemStoreW
   201  //sys   CertOpenStore(storeProvider uintptr, msgAndCertEncodingType uint32, cryptProv uintptr, flags uint32, para uintptr) (handle Handle, err error) [failretval==InvalidHandle] = crypt32.CertOpenStore
   202  //sys	CertEnumCertificatesInStore(store Handle, prevContext *CertContext) (context *CertContext, err error) [failretval==nil] = crypt32.CertEnumCertificatesInStore
   203  //sys   CertAddCertificateContextToStore(store Handle, certContext *CertContext, addDisposition uint32, storeContext **CertContext) (err error) = crypt32.CertAddCertificateContextToStore
   204  //sys	CertCloseStore(store Handle, flags uint32) (err error) = crypt32.CertCloseStore
   205  //sys   CertGetCertificateChain(engine Handle, leaf *CertContext, time *Filetime, additionalStore Handle, para *CertChainPara, flags uint32, reserved uintptr, chainCtx **CertChainContext) (err error) = crypt32.CertGetCertificateChain
   206  //sys   CertFreeCertificateChain(ctx *CertChainContext) = crypt32.CertFreeCertificateChain
   207  //sys   CertCreateCertificateContext(certEncodingType uint32, certEncoded *byte, encodedLen uint32) (context *CertContext, err error) [failretval==nil] = crypt32.CertCreateCertificateContext
   208  //sys   CertFreeCertificateContext(ctx *CertContext) (err error) = crypt32.CertFreeCertificateContext
   209  //sys   CertVerifyCertificateChainPolicy(policyOID uintptr, chain *CertChainContext, para *CertChainPolicyPara, status *CertChainPolicyStatus) (err error) = crypt32.CertVerifyCertificateChainPolicy
   210  //sys	RegOpenKeyEx(key Handle, subkey *uint16, options uint32, desiredAccess uint32, result *Handle) (regerrno error) = advapi32.RegOpenKeyExW
   211  //sys	RegCloseKey(key Handle) (regerrno error) = advapi32.RegCloseKey
   212  //sys	RegQueryInfoKey(key Handle, class *uint16, classLen *uint32, reserved *uint32, subkeysLen *uint32, maxSubkeyLen *uint32, maxClassLen *uint32, valuesLen *uint32, maxValueNameLen *uint32, maxValueLen *uint32, saLen *uint32, lastWriteTime *Filetime) (regerrno error) = advapi32.RegQueryInfoKeyW
   213  //sys	RegEnumKeyEx(key Handle, index uint32, name *uint16, nameLen *uint32, reserved *uint32, class *uint16, classLen *uint32, lastWriteTime *Filetime) (regerrno error) = advapi32.RegEnumKeyExW
   214  //sys	RegQueryValueEx(key Handle, name *uint16, reserved *uint32, valtype *uint32, buf *byte, buflen *uint32) (regerrno error) = advapi32.RegQueryValueExW
   215  //sys	getCurrentProcessId() (pid uint32) = kernel32.GetCurrentProcessId
   216  //sys	GetConsoleMode(console Handle, mode *uint32) (err error) = kernel32.GetConsoleMode
   217  //sys	WriteConsole(console Handle, buf *uint16, towrite uint32, written *uint32, reserved *byte) (err error) = kernel32.WriteConsoleW
   218  //sys	ReadConsole(console Handle, buf *uint16, toread uint32, read *uint32, inputControl *byte) (err error) = kernel32.ReadConsoleW
   219  //sys	CreateToolhelp32Snapshot(flags uint32, processId uint32) (handle Handle, err error) [failretval==InvalidHandle] = kernel32.CreateToolhelp32Snapshot
   220  //sys	Process32First(snapshot Handle, procEntry *ProcessEntry32) (err error) = kernel32.Process32FirstW
   221  //sys	Process32Next(snapshot Handle, procEntry *ProcessEntry32) (err error) = kernel32.Process32NextW
   222  //sys	DeviceIoControl(handle Handle, ioControlCode uint32, inBuffer *byte, inBufferSize uint32, outBuffer *byte, outBufferSize uint32, bytesReturned *uint32, overlapped *Overlapped) (err error)
   223  // This function returns 1 byte BOOLEAN rather than the 4 byte BOOL.
   224  //sys	CreateSymbolicLink(symlinkfilename *uint16, targetfilename *uint16, flags uint32) (err error) [failretval&0xff==0] = CreateSymbolicLinkW
   225  //sys	CreateHardLink(filename *uint16, existingfilename *uint16, reserved uintptr) (err error) [failretval&0xff==0] = CreateHardLinkW
   226  
   227  // syscall interface implementation for other packages
   228  
   229  func Exit(code int) { ExitProcess(uint32(code)) }
   230  
   231  func makeInheritSa() *SecurityAttributes {
   232  	var sa SecurityAttributes
   233  	sa.Length = uint32(unsafe.Sizeof(sa))
   234  	sa.InheritHandle = 1
   235  	return &sa
   236  }
   237  
   238  func Open(path string, mode int, perm uint32) (fd Handle, err error) {
   239  	if len(path) == 0 {
   240  		return InvalidHandle, ERROR_FILE_NOT_FOUND
   241  	}
   242  	pathp, err := UTF16PtrFromString(path)
   243  	if err != nil {
   244  		return InvalidHandle, err
   245  	}
   246  	var access uint32
   247  	switch mode & (O_RDONLY | O_WRONLY | O_RDWR) {
   248  	case O_RDONLY:
   249  		access = GENERIC_READ
   250  	case O_WRONLY:
   251  		access = GENERIC_WRITE
   252  	case O_RDWR:
   253  		access = GENERIC_READ | GENERIC_WRITE
   254  	}
   255  	if mode&O_CREAT != 0 {
   256  		access |= GENERIC_WRITE
   257  	}
   258  	if mode&O_APPEND != 0 {
   259  		access &^= GENERIC_WRITE
   260  		access |= FILE_APPEND_DATA
   261  	}
   262  	sharemode := uint32(FILE_SHARE_READ | FILE_SHARE_WRITE)
   263  	var sa *SecurityAttributes
   264  	if mode&O_CLOEXEC == 0 {
   265  		sa = makeInheritSa()
   266  	}
   267  	var createmode uint32
   268  	switch {
   269  	case mode&(O_CREAT|O_EXCL) == (O_CREAT | O_EXCL):
   270  		createmode = CREATE_NEW
   271  	case mode&(O_CREAT|O_TRUNC) == (O_CREAT | O_TRUNC):
   272  		createmode = CREATE_ALWAYS
   273  	case mode&O_CREAT == O_CREAT:
   274  		createmode = OPEN_ALWAYS
   275  	case mode&O_TRUNC == O_TRUNC:
   276  		createmode = TRUNCATE_EXISTING
   277  	default:
   278  		createmode = OPEN_EXISTING
   279  	}
   280  	h, e := CreateFile(pathp, access, sharemode, sa, createmode, FILE_ATTRIBUTE_NORMAL, 0)
   281  	return h, e
   282  }
   283  
   284  func Read(fd Handle, p []byte) (n int, err error) {
   285  	var done uint32
   286  	e := ReadFile(fd, p, &done, nil)
   287  	if e != nil {
   288  		if e == ERROR_BROKEN_PIPE {
   289  			// NOTE(brainman): work around ERROR_BROKEN_PIPE is returned on reading EOF from stdin
   290  			return 0, nil
   291  		}
   292  		return 0, e
   293  	}
   294  	if raceenabled {
   295  		if done > 0 {
   296  			raceWriteRange(unsafe.Pointer(&p[0]), int(done))
   297  		}
   298  		raceAcquire(unsafe.Pointer(&ioSync))
   299  	}
   300  	return int(done), nil
   301  }
   302  
   303  func Write(fd Handle, p []byte) (n int, err error) {
   304  	if raceenabled {
   305  		raceReleaseMerge(unsafe.Pointer(&ioSync))
   306  	}
   307  	var done uint32
   308  	e := WriteFile(fd, p, &done, nil)
   309  	if e != nil {
   310  		return 0, e
   311  	}
   312  	if raceenabled && done > 0 {
   313  		raceReadRange(unsafe.Pointer(&p[0]), int(done))
   314  	}
   315  	return int(done), nil
   316  }
   317  
   318  var ioSync int64
   319  
   320  func Seek(fd Handle, offset int64, whence int) (newoffset int64, err error) {
   321  	var w uint32
   322  	switch whence {
   323  	case 0:
   324  		w = FILE_BEGIN
   325  	case 1:
   326  		w = FILE_CURRENT
   327  	case 2:
   328  		w = FILE_END
   329  	}
   330  	hi := int32(offset >> 32)
   331  	lo := int32(offset)
   332  	// use GetFileType to check pipe, pipe can't do seek
   333  	ft, _ := GetFileType(fd)
   334  	if ft == FILE_TYPE_PIPE {
   335  		return 0, EPIPE
   336  	}
   337  	rlo, e := SetFilePointer(fd, lo, &hi, w)
   338  	if e != nil {
   339  		return 0, e
   340  	}
   341  	return int64(hi)<<32 + int64(rlo), nil
   342  }
   343  
   344  func Close(fd Handle) (err error) {
   345  	return CloseHandle(fd)
   346  }
   347  
   348  var (
   349  	Stdin  = getStdHandle(STD_INPUT_HANDLE)
   350  	Stdout = getStdHandle(STD_OUTPUT_HANDLE)
   351  	Stderr = getStdHandle(STD_ERROR_HANDLE)
   352  )
   353  
   354  func getStdHandle(h int) (fd Handle) {
   355  	r, _ := GetStdHandle(h)
   356  	CloseOnExec(r)
   357  	return r
   358  }
   359  
   360  const ImplementsGetwd = true
   361  
   362  func Getwd() (wd string, err error) {
   363  	b := make([]uint16, 300)
   364  	n, e := GetCurrentDirectory(uint32(len(b)), &b[0])
   365  	if e != nil {
   366  		return "", e
   367  	}
   368  	return string(utf16.Decode(b[0:n])), nil
   369  }
   370  
   371  func Chdir(path string) (err error) {
   372  	pathp, err := UTF16PtrFromString(path)
   373  	if err != nil {
   374  		return err
   375  	}
   376  	return SetCurrentDirectory(pathp)
   377  }
   378  
   379  func Mkdir(path string, mode uint32) (err error) {
   380  	pathp, err := UTF16PtrFromString(path)
   381  	if err != nil {
   382  		return err
   383  	}
   384  	return CreateDirectory(pathp, nil)
   385  }
   386  
   387  func Rmdir(path string) (err error) {
   388  	pathp, err := UTF16PtrFromString(path)
   389  	if err != nil {
   390  		return err
   391  	}
   392  	return RemoveDirectory(pathp)
   393  }
   394  
   395  func Unlink(path string) (err error) {
   396  	pathp, err := UTF16PtrFromString(path)
   397  	if err != nil {
   398  		return err
   399  	}
   400  	return DeleteFile(pathp)
   401  }
   402  
   403  func Rename(oldpath, newpath string) (err error) {
   404  	from, err := UTF16PtrFromString(oldpath)
   405  	if err != nil {
   406  		return err
   407  	}
   408  	to, err := UTF16PtrFromString(newpath)
   409  	if err != nil {
   410  		return err
   411  	}
   412  	return MoveFile(from, to)
   413  }
   414  
   415  func ComputerName() (name string, err error) {
   416  	var n uint32 = MAX_COMPUTERNAME_LENGTH + 1
   417  	b := make([]uint16, n)
   418  	e := GetComputerName(&b[0], &n)
   419  	if e != nil {
   420  		return "", e
   421  	}
   422  	return string(utf16.Decode(b[0:n])), nil
   423  }
   424  
   425  func Ftruncate(fd Handle, length int64) (err error) {
   426  	curoffset, e := Seek(fd, 0, 1)
   427  	if e != nil {
   428  		return e
   429  	}
   430  	defer Seek(fd, curoffset, 0)
   431  	_, e = Seek(fd, length, 0)
   432  	if e != nil {
   433  		return e
   434  	}
   435  	e = SetEndOfFile(fd)
   436  	if e != nil {
   437  		return e
   438  	}
   439  	return nil
   440  }
   441  
   442  func Gettimeofday(tv *Timeval) (err error) {
   443  	var ft Filetime
   444  	GetSystemTimeAsFileTime(&ft)
   445  	*tv = NsecToTimeval(ft.Nanoseconds())
   446  	return nil
   447  }
   448  
   449  func Pipe(p []Handle) (err error) {
   450  	if len(p) != 2 {
   451  		return EINVAL
   452  	}
   453  	var r, w Handle
   454  	e := CreatePipe(&r, &w, makeInheritSa(), 0)
   455  	if e != nil {
   456  		return e
   457  	}
   458  	p[0] = r
   459  	p[1] = w
   460  	return nil
   461  }
   462  
   463  func Utimes(path string, tv []Timeval) (err error) {
   464  	if len(tv) != 2 {
   465  		return EINVAL
   466  	}
   467  	pathp, e := UTF16PtrFromString(path)
   468  	if e != nil {
   469  		return e
   470  	}
   471  	h, e := CreateFile(pathp,
   472  		FILE_WRITE_ATTRIBUTES, FILE_SHARE_WRITE, nil,
   473  		OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, 0)
   474  	if e != nil {
   475  		return e
   476  	}
   477  	defer Close(h)
   478  	a := NsecToFiletime(tv[0].Nanoseconds())
   479  	w := NsecToFiletime(tv[1].Nanoseconds())
   480  	return SetFileTime(h, nil, &a, &w)
   481  }
   482  
   483  func UtimesNano(path string, ts []Timespec) (err error) {
   484  	if len(ts) != 2 {
   485  		return EINVAL
   486  	}
   487  	pathp, e := UTF16PtrFromString(path)
   488  	if e != nil {
   489  		return e
   490  	}
   491  	h, e := CreateFile(pathp,
   492  		FILE_WRITE_ATTRIBUTES, FILE_SHARE_WRITE, nil,
   493  		OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, 0)
   494  	if e != nil {
   495  		return e
   496  	}
   497  	defer Close(h)
   498  	a := NsecToFiletime(TimespecToNsec(ts[0]))
   499  	w := NsecToFiletime(TimespecToNsec(ts[1]))
   500  	return SetFileTime(h, nil, &a, &w)
   501  }
   502  
   503  func Fsync(fd Handle) (err error) {
   504  	return FlushFileBuffers(fd)
   505  }
   506  
   507  func Chmod(path string, mode uint32) (err error) {
   508  	if mode == 0 {
   509  		return EINVAL
   510  	}
   511  	p, e := UTF16PtrFromString(path)
   512  	if e != nil {
   513  		return e
   514  	}
   515  	attrs, e := GetFileAttributes(p)
   516  	if e != nil {
   517  		return e
   518  	}
   519  	if mode&S_IWRITE != 0 {
   520  		attrs &^= FILE_ATTRIBUTE_READONLY
   521  	} else {
   522  		attrs |= FILE_ATTRIBUTE_READONLY
   523  	}
   524  	return SetFileAttributes(p, attrs)
   525  }
   526  
   527  func LoadCancelIoEx() error {
   528  	return procCancelIoEx.Find()
   529  }
   530  
   531  func LoadSetFileCompletionNotificationModes() error {
   532  	return procSetFileCompletionNotificationModes.Find()
   533  }
   534  
   535  // net api calls
   536  
   537  const socket_error = uintptr(^uint32(0))
   538  
   539  //sys	WSAStartup(verreq uint32, data *WSAData) (sockerr error) = ws2_32.WSAStartup
   540  //sys	WSACleanup() (err error) [failretval==socket_error] = ws2_32.WSACleanup
   541  //sys	WSAIoctl(s Handle, iocc uint32, inbuf *byte, cbif uint32, outbuf *byte, cbob uint32, cbbr *uint32, overlapped *Overlapped, completionRoutine uintptr) (err error) [failretval==socket_error] = ws2_32.WSAIoctl
   542  //sys	socket(af int32, typ int32, protocol int32) (handle Handle, err error) [failretval==InvalidHandle] = ws2_32.socket
   543  //sys	Setsockopt(s Handle, level int32, optname int32, optval *byte, optlen int32) (err error) [failretval==socket_error] = ws2_32.setsockopt
   544  //sys	Getsockopt(s Handle, level int32, optname int32, optval *byte, optlen *int32) (err error) [failretval==socket_error] = ws2_32.getsockopt
   545  //sys	bind(s Handle, name unsafe.Pointer, namelen int32) (err error) [failretval==socket_error] = ws2_32.bind
   546  //sys	connect(s Handle, name unsafe.Pointer, namelen int32) (err error) [failretval==socket_error] = ws2_32.connect
   547  //sys	getsockname(s Handle, rsa *RawSockaddrAny, addrlen *int32) (err error) [failretval==socket_error] = ws2_32.getsockname
   548  //sys	getpeername(s Handle, rsa *RawSockaddrAny, addrlen *int32) (err error) [failretval==socket_error] = ws2_32.getpeername
   549  //sys	listen(s Handle, backlog int32) (err error) [failretval==socket_error] = ws2_32.listen
   550  //sys	shutdown(s Handle, how int32) (err error) [failretval==socket_error] = ws2_32.shutdown
   551  //sys	Closesocket(s Handle) (err error) [failretval==socket_error] = ws2_32.closesocket
   552  //sys	AcceptEx(ls Handle, as Handle, buf *byte, rxdatalen uint32, laddrlen uint32, raddrlen uint32, recvd *uint32, overlapped *Overlapped) (err error) = mswsock.AcceptEx
   553  //sys	GetAcceptExSockaddrs(buf *byte, rxdatalen uint32, laddrlen uint32, raddrlen uint32, lrsa **RawSockaddrAny, lrsalen *int32, rrsa **RawSockaddrAny, rrsalen *int32) = mswsock.GetAcceptExSockaddrs
   554  //sys	WSARecv(s Handle, bufs *WSABuf, bufcnt uint32, recvd *uint32, flags *uint32, overlapped *Overlapped, croutine *byte) (err error) [failretval==socket_error] = ws2_32.WSARecv
   555  //sys	WSASend(s Handle, bufs *WSABuf, bufcnt uint32, sent *uint32, flags uint32, overlapped *Overlapped, croutine *byte) (err error) [failretval==socket_error] = ws2_32.WSASend
   556  //sys	WSARecvFrom(s Handle, bufs *WSABuf, bufcnt uint32, recvd *uint32, flags *uint32,  from *RawSockaddrAny, fromlen *int32, overlapped *Overlapped, croutine *byte) (err error) [failretval==socket_error] = ws2_32.WSARecvFrom
   557  //sys	WSASendTo(s Handle, bufs *WSABuf, bufcnt uint32, sent *uint32, flags uint32, to *RawSockaddrAny, tolen int32,  overlapped *Overlapped, croutine *byte) (err error) [failretval==socket_error] = ws2_32.WSASendTo
   558  //sys	GetHostByName(name string) (h *Hostent, err error) [failretval==nil] = ws2_32.gethostbyname
   559  //sys	GetServByName(name string, proto string) (s *Servent, err error) [failretval==nil] = ws2_32.getservbyname
   560  //sys	Ntohs(netshort uint16) (u uint16) = ws2_32.ntohs
   561  //sys	GetProtoByName(name string) (p *Protoent, err error) [failretval==nil] = ws2_32.getprotobyname
   562  //sys	DnsQuery(name string, qtype uint16, options uint32, extra *byte, qrs **DNSRecord, pr *byte) (status error) = dnsapi.DnsQuery_W
   563  //sys	DnsRecordListFree(rl *DNSRecord, freetype uint32) = dnsapi.DnsRecordListFree
   564  //sys	DnsNameCompare(name1 *uint16, name2 *uint16) (same bool) = dnsapi.DnsNameCompare_W
   565  //sys	GetAddrInfoW(nodename *uint16, servicename *uint16, hints *AddrinfoW, result **AddrinfoW) (sockerr error) = ws2_32.GetAddrInfoW
   566  //sys	FreeAddrInfoW(addrinfo *AddrinfoW) = ws2_32.FreeAddrInfoW
   567  //sys	GetIfEntry(pIfRow *MibIfRow) (errcode error) = iphlpapi.GetIfEntry
   568  //sys	GetAdaptersInfo(ai *IpAdapterInfo, ol *uint32) (errcode error) = iphlpapi.GetAdaptersInfo
   569  //sys	SetFileCompletionNotificationModes(handle Handle, flags uint8) (err error) = kernel32.SetFileCompletionNotificationModes
   570  //sys	WSAEnumProtocols(protocols *int32, protocolBuffer *WSAProtocolInfo, bufferLength *uint32) (n int32, err error) [failretval==-1] = ws2_32.WSAEnumProtocolsW
   571  
   572  // For testing: clients can set this flag to force
   573  // creation of IPv6 sockets to return EAFNOSUPPORT.
   574  var SocketDisableIPv6 bool
   575  
   576  type RawSockaddrInet4 struct {
   577  	Family uint16
   578  	Port   uint16
   579  	Addr   [4]byte /* in_addr */
   580  	Zero   [8]uint8
   581  }
   582  
   583  type RawSockaddrInet6 struct {
   584  	Family   uint16
   585  	Port     uint16
   586  	Flowinfo uint32
   587  	Addr     [16]byte /* in6_addr */
   588  	Scope_id uint32
   589  }
   590  
   591  type RawSockaddr struct {
   592  	Family uint16
   593  	Data   [14]int8
   594  }
   595  
   596  type RawSockaddrAny struct {
   597  	Addr RawSockaddr
   598  	Pad  [96]int8
   599  }
   600  
   601  type Sockaddr interface {
   602  	sockaddr() (ptr unsafe.Pointer, len int32, err error) // lowercase; only we can define Sockaddrs
   603  }
   604  
   605  type SockaddrInet4 struct {
   606  	Port int
   607  	Addr [4]byte
   608  	raw  RawSockaddrInet4
   609  }
   610  
   611  func (sa *SockaddrInet4) sockaddr() (unsafe.Pointer, int32, error) {
   612  	if sa.Port < 0 || sa.Port > 0xFFFF {
   613  		return nil, 0, EINVAL
   614  	}
   615  	sa.raw.Family = AF_INET
   616  	p := (*[2]byte)(unsafe.Pointer(&sa.raw.Port))
   617  	p[0] = byte(sa.Port >> 8)
   618  	p[1] = byte(sa.Port)
   619  	for i := 0; i < len(sa.Addr); i++ {
   620  		sa.raw.Addr[i] = sa.Addr[i]
   621  	}
   622  	return unsafe.Pointer(&sa.raw), int32(unsafe.Sizeof(sa.raw)), nil
   623  }
   624  
   625  type SockaddrInet6 struct {
   626  	Port   int
   627  	ZoneId uint32
   628  	Addr   [16]byte
   629  	raw    RawSockaddrInet6
   630  }
   631  
   632  func (sa *SockaddrInet6) sockaddr() (unsafe.Pointer, int32, error) {
   633  	if sa.Port < 0 || sa.Port > 0xFFFF {
   634  		return nil, 0, EINVAL
   635  	}
   636  	sa.raw.Family = AF_INET6
   637  	p := (*[2]byte)(unsafe.Pointer(&sa.raw.Port))
   638  	p[0] = byte(sa.Port >> 8)
   639  	p[1] = byte(sa.Port)
   640  	sa.raw.Scope_id = sa.ZoneId
   641  	for i := 0; i < len(sa.Addr); i++ {
   642  		sa.raw.Addr[i] = sa.Addr[i]
   643  	}
   644  	return unsafe.Pointer(&sa.raw), int32(unsafe.Sizeof(sa.raw)), nil
   645  }
   646  
   647  type SockaddrUnix struct {
   648  	Name string
   649  }
   650  
   651  func (sa *SockaddrUnix) sockaddr() (unsafe.Pointer, int32, error) {
   652  	// TODO(brainman): implement SockaddrUnix.sockaddr()
   653  	return nil, 0, EWINDOWS
   654  }
   655  
   656  func (rsa *RawSockaddrAny) Sockaddr() (Sockaddr, error) {
   657  	switch rsa.Addr.Family {
   658  	case AF_UNIX:
   659  		return nil, EWINDOWS
   660  
   661  	case AF_INET:
   662  		pp := (*RawSockaddrInet4)(unsafe.Pointer(rsa))
   663  		sa := new(SockaddrInet4)
   664  		p := (*[2]byte)(unsafe.Pointer(&pp.Port))
   665  		sa.Port = int(p[0])<<8 + int(p[1])
   666  		for i := 0; i < len(sa.Addr); i++ {
   667  			sa.Addr[i] = pp.Addr[i]
   668  		}
   669  		return sa, nil
   670  
   671  	case AF_INET6:
   672  		pp := (*RawSockaddrInet6)(unsafe.Pointer(rsa))
   673  		sa := new(SockaddrInet6)
   674  		p := (*[2]byte)(unsafe.Pointer(&pp.Port))
   675  		sa.Port = int(p[0])<<8 + int(p[1])
   676  		sa.ZoneId = pp.Scope_id
   677  		for i := 0; i < len(sa.Addr); i++ {
   678  			sa.Addr[i] = pp.Addr[i]
   679  		}
   680  		return sa, nil
   681  	}
   682  	return nil, EAFNOSUPPORT
   683  }
   684  
   685  func Socket(domain, typ, proto int) (fd Handle, err error) {
   686  	if domain == AF_INET6 && SocketDisableIPv6 {
   687  		return InvalidHandle, EAFNOSUPPORT
   688  	}
   689  	return socket(int32(domain), int32(typ), int32(proto))
   690  }
   691  
   692  func SetsockoptInt(fd Handle, level, opt int, value int) (err error) {
   693  	v := int32(value)
   694  	return Setsockopt(fd, int32(level), int32(opt), (*byte)(unsafe.Pointer(&v)), int32(unsafe.Sizeof(v)))
   695  }
   696  
   697  func Bind(fd Handle, sa Sockaddr) (err error) {
   698  	ptr, n, err := sa.sockaddr()
   699  	if err != nil {
   700  		return err
   701  	}
   702  	return bind(fd, ptr, n)
   703  }
   704  
   705  func Connect(fd Handle, sa Sockaddr) (err error) {
   706  	ptr, n, err := sa.sockaddr()
   707  	if err != nil {
   708  		return err
   709  	}
   710  	return connect(fd, ptr, n)
   711  }
   712  
   713  func Getsockname(fd Handle) (sa Sockaddr, err error) {
   714  	var rsa RawSockaddrAny
   715  	l := int32(unsafe.Sizeof(rsa))
   716  	if err = getsockname(fd, &rsa, &l); err != nil {
   717  		return
   718  	}
   719  	return rsa.Sockaddr()
   720  }
   721  
   722  func Getpeername(fd Handle) (sa Sockaddr, err error) {
   723  	var rsa RawSockaddrAny
   724  	l := int32(unsafe.Sizeof(rsa))
   725  	if err = getpeername(fd, &rsa, &l); err != nil {
   726  		return
   727  	}
   728  	return rsa.Sockaddr()
   729  }
   730  
   731  func Listen(s Handle, n int) (err error) {
   732  	return listen(s, int32(n))
   733  }
   734  
   735  func Shutdown(fd Handle, how int) (err error) {
   736  	return shutdown(fd, int32(how))
   737  }
   738  
   739  func WSASendto(s Handle, bufs *WSABuf, bufcnt uint32, sent *uint32, flags uint32, to Sockaddr, overlapped *Overlapped, croutine *byte) (err error) {
   740  	rsa, l, err := to.sockaddr()
   741  	if err != nil {
   742  		return err
   743  	}
   744  	return WSASendTo(s, bufs, bufcnt, sent, flags, (*RawSockaddrAny)(unsafe.Pointer(rsa)), l, overlapped, croutine)
   745  }
   746  
   747  func LoadGetAddrInfo() error {
   748  	return procGetAddrInfoW.Find()
   749  }
   750  
   751  var connectExFunc struct {
   752  	once sync.Once
   753  	addr uintptr
   754  	err  error
   755  }
   756  
   757  func LoadConnectEx() error {
   758  	connectExFunc.once.Do(func() {
   759  		var s Handle
   760  		s, connectExFunc.err = Socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)
   761  		if connectExFunc.err != nil {
   762  			return
   763  		}
   764  		defer CloseHandle(s)
   765  		var n uint32
   766  		connectExFunc.err = WSAIoctl(s,
   767  			SIO_GET_EXTENSION_FUNCTION_POINTER,
   768  			(*byte)(unsafe.Pointer(&WSAID_CONNECTEX)),
   769  			uint32(unsafe.Sizeof(WSAID_CONNECTEX)),
   770  			(*byte)(unsafe.Pointer(&connectExFunc.addr)),
   771  			uint32(unsafe.Sizeof(connectExFunc.addr)),
   772  			&n, nil, 0)
   773  	})
   774  	return connectExFunc.err
   775  }
   776  
   777  func connectEx(s Handle, name unsafe.Pointer, namelen int32, sendBuf *byte, sendDataLen uint32, bytesSent *uint32, overlapped *Overlapped) (err error) {
   778  	r1, _, e1 := Syscall9(connectExFunc.addr, 7, uintptr(s), uintptr(name), uintptr(namelen), uintptr(unsafe.Pointer(sendBuf)), uintptr(sendDataLen), uintptr(unsafe.Pointer(bytesSent)), uintptr(unsafe.Pointer(overlapped)), 0, 0)
   779  	if r1 == 0 {
   780  		if e1 != 0 {
   781  			err = error(e1)
   782  		} else {
   783  			err = EINVAL
   784  		}
   785  	}
   786  	return
   787  }
   788  
   789  func ConnectEx(fd Handle, sa Sockaddr, sendBuf *byte, sendDataLen uint32, bytesSent *uint32, overlapped *Overlapped) error {
   790  	err := LoadConnectEx()
   791  	if err != nil {
   792  		return errorspkg.New("failed to find ConnectEx: " + err.Error())
   793  	}
   794  	ptr, n, err := sa.sockaddr()
   795  	if err != nil {
   796  		return err
   797  	}
   798  	return connectEx(fd, ptr, n, sendBuf, sendDataLen, bytesSent, overlapped)
   799  }
   800  
   801  // Invented structures to support what package os expects.
   802  type Rusage struct {
   803  	CreationTime Filetime
   804  	ExitTime     Filetime
   805  	KernelTime   Filetime
   806  	UserTime     Filetime
   807  }
   808  
   809  type WaitStatus struct {
   810  	ExitCode uint32
   811  }
   812  
   813  func (w WaitStatus) Exited() bool { return true }
   814  
   815  func (w WaitStatus) ExitStatus() int { return int(w.ExitCode) }
   816  
   817  func (w WaitStatus) Signal() Signal { return -1 }
   818  
   819  func (w WaitStatus) CoreDump() bool { return false }
   820  
   821  func (w WaitStatus) Stopped() bool { return false }
   822  
   823  func (w WaitStatus) Continued() bool { return false }
   824  
   825  func (w WaitStatus) StopSignal() Signal { return -1 }
   826  
   827  func (w WaitStatus) Signaled() bool { return false }
   828  
   829  func (w WaitStatus) TrapCause() int { return -1 }
   830  
   831  // Timespec is an invented structure on Windows, but here for
   832  // consistency with the syscall package for other operating systems.
   833  type Timespec struct {
   834  	Sec  int64
   835  	Nsec int64
   836  }
   837  
   838  func TimespecToNsec(ts Timespec) int64 { return int64(ts.Sec)*1e9 + int64(ts.Nsec) }
   839  
   840  func NsecToTimespec(nsec int64) (ts Timespec) {
   841  	ts.Sec = nsec / 1e9
   842  	ts.Nsec = nsec % 1e9
   843  	return
   844  }
   845  
   846  // TODO(brainman): fix all needed for net
   847  
   848  func Accept(fd Handle) (nfd Handle, sa Sockaddr, err error) { return 0, nil, EWINDOWS }
   849  func Recvfrom(fd Handle, p []byte, flags int) (n int, from Sockaddr, err error) {
   850  	return 0, nil, EWINDOWS
   851  }
   852  func Sendto(fd Handle, p []byte, flags int, to Sockaddr) (err error)       { return EWINDOWS }
   853  func SetsockoptTimeval(fd Handle, level, opt int, tv *Timeval) (err error) { return EWINDOWS }
   854  
   855  // The Linger struct is wrong but we only noticed after Go 1.
   856  // sysLinger is the real system call structure.
   857  
   858  // BUG(brainman): The definition of Linger is not appropriate for direct use
   859  // with Setsockopt and Getsockopt.
   860  // Use SetsockoptLinger instead.
   861  
   862  type Linger struct {
   863  	Onoff  int32
   864  	Linger int32
   865  }
   866  
   867  type sysLinger struct {
   868  	Onoff  uint16
   869  	Linger uint16
   870  }
   871  
   872  type IPMreq struct {
   873  	Multiaddr [4]byte /* in_addr */
   874  	Interface [4]byte /* in_addr */
   875  }
   876  
   877  type IPv6Mreq struct {
   878  	Multiaddr [16]byte /* in6_addr */
   879  	Interface uint32
   880  }
   881  
   882  func GetsockoptInt(fd Handle, level, opt int) (int, error) { return -1, EWINDOWS }
   883  
   884  func SetsockoptLinger(fd Handle, level, opt int, l *Linger) (err error) {
   885  	sys := sysLinger{Onoff: uint16(l.Onoff), Linger: uint16(l.Linger)}
   886  	return Setsockopt(fd, int32(level), int32(opt), (*byte)(unsafe.Pointer(&sys)), int32(unsafe.Sizeof(sys)))
   887  }
   888  
   889  func SetsockoptInet4Addr(fd Handle, level, opt int, value [4]byte) (err error) {
   890  	return Setsockopt(fd, int32(level), int32(opt), (*byte)(unsafe.Pointer(&value[0])), 4)
   891  }
   892  func SetsockoptIPMreq(fd Handle, level, opt int, mreq *IPMreq) (err error) {
   893  	return Setsockopt(fd, int32(level), int32(opt), (*byte)(unsafe.Pointer(mreq)), int32(unsafe.Sizeof(*mreq)))
   894  }
   895  func SetsockoptIPv6Mreq(fd Handle, level, opt int, mreq *IPv6Mreq) (err error) { return EWINDOWS }
   896  
   897  func Getpid() (pid int) { return int(getCurrentProcessId()) }
   898  
   899  func FindFirstFile(name *uint16, data *Win32finddata) (handle Handle, err error) {
   900  	// NOTE(rsc): The Win32finddata struct is wrong for the system call:
   901  	// the two paths are each one uint16 short. Use the correct struct,
   902  	// a win32finddata1, and then copy the results out.
   903  	// There is no loss of expressivity here, because the final
   904  	// uint16, if it is used, is supposed to be a NUL, and Go doesn't need that.
   905  	// For Go 1.1, we might avoid the allocation of win32finddata1 here
   906  	// by adding a final Bug [2]uint16 field to the struct and then
   907  	// adjusting the fields in the result directly.
   908  	var data1 win32finddata1
   909  	handle, err = findFirstFile1(name, &data1)
   910  	if err == nil {
   911  		copyFindData(data, &data1)
   912  	}
   913  	return
   914  }
   915  
   916  func FindNextFile(handle Handle, data *Win32finddata) (err error) {
   917  	var data1 win32finddata1
   918  	err = findNextFile1(handle, &data1)
   919  	if err == nil {
   920  		copyFindData(data, &data1)
   921  	}
   922  	return
   923  }
   924  
   925  func getProcessEntry(pid int) (*ProcessEntry32, error) {
   926  	snapshot, err := CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0)
   927  	if err != nil {
   928  		return nil, err
   929  	}
   930  	defer CloseHandle(snapshot)
   931  	var procEntry ProcessEntry32
   932  	procEntry.Size = uint32(unsafe.Sizeof(procEntry))
   933  	if err = Process32First(snapshot, &procEntry); err != nil {
   934  		return nil, err
   935  	}
   936  	for {
   937  		if procEntry.ProcessID == uint32(pid) {
   938  			return &procEntry, nil
   939  		}
   940  		err = Process32Next(snapshot, &procEntry)
   941  		if err != nil {
   942  			return nil, err
   943  		}
   944  	}
   945  }
   946  
   947  func Getppid() (ppid int) {
   948  	pe, err := getProcessEntry(Getpid())
   949  	if err != nil {
   950  		return -1
   951  	}
   952  	return int(pe.ParentProcessID)
   953  }
   954  
   955  // TODO(brainman): fix all needed for os
   956  func Fchdir(fd Handle) (err error)             { return EWINDOWS }
   957  func Link(oldpath, newpath string) (err error) { return EWINDOWS }
   958  func Symlink(path, link string) (err error)    { return EWINDOWS }
   959  
   960  func Fchmod(fd Handle, mode uint32) (err error)        { return EWINDOWS }
   961  func Chown(path string, uid int, gid int) (err error)  { return EWINDOWS }
   962  func Lchown(path string, uid int, gid int) (err error) { return EWINDOWS }
   963  func Fchown(fd Handle, uid int, gid int) (err error)   { return EWINDOWS }
   964  
   965  func Getuid() (uid int)                  { return -1 }
   966  func Geteuid() (euid int)                { return -1 }
   967  func Getgid() (gid int)                  { return -1 }
   968  func Getegid() (egid int)                { return -1 }
   969  func Getgroups() (gids []int, err error) { return nil, EWINDOWS }
   970  
   971  type Signal int
   972  
   973  func (s Signal) Signal() {}
   974  
   975  func (s Signal) String() string {
   976  	if 0 <= s && int(s) < len(signals) {
   977  		str := signals[s]
   978  		if str != "" {
   979  			return str
   980  		}
   981  	}
   982  	return "signal " + itoa(int(s))
   983  }
   984  
   985  func LoadCreateSymbolicLink() error {
   986  	return procCreateSymbolicLinkW.Find()
   987  }
   988  
   989  // Readlink returns the destination of the named symbolic link.
   990  func Readlink(path string, buf []byte) (n int, err error) {
   991  	fd, err := CreateFile(StringToUTF16Ptr(path), GENERIC_READ, 0, nil, OPEN_EXISTING,
   992  		FILE_FLAG_OPEN_REPARSE_POINT|FILE_FLAG_BACKUP_SEMANTICS, 0)
   993  	if err != nil {
   994  		return -1, err
   995  	}
   996  	defer CloseHandle(fd)
   997  
   998  	rdbbuf := make([]byte, MAXIMUM_REPARSE_DATA_BUFFER_SIZE)
   999  	var bytesReturned uint32
  1000  	err = DeviceIoControl(fd, FSCTL_GET_REPARSE_POINT, nil, 0, &rdbbuf[0], uint32(len(rdbbuf)), &bytesReturned, nil)
  1001  	if err != nil {
  1002  		return -1, err
  1003  	}
  1004  
  1005  	rdb := (*reparseDataBuffer)(unsafe.Pointer(&rdbbuf[0]))
  1006  	if uintptr(bytesReturned) < unsafe.Sizeof(*rdb) ||
  1007  		rdb.ReparseTag != IO_REPARSE_TAG_SYMLINK {
  1008  		// the path is not a symlink but another type of reparse point
  1009  		return -1, ENOENT
  1010  	}
  1011  
  1012  	s := UTF16ToString((*[0xffff]uint16)(unsafe.Pointer(&rdb.PathBuffer[0]))[:rdb.PrintNameLength/2])
  1013  	n = copy(buf, []byte(s))
  1014  	return n, nil
  1015  }