mirror of
https://github.com/golang/go
synced 2024-10-02 12:18:33 -06:00
6407b3c80e
windows version of Pipe function is implemented by calling syscall.Pipe which returns handles inheritable by client process, and then adjusting returned handles with syscall.CloseOnExec. Just create non-inheritable handles in the first place. Now that we don't have a race window in the code, drop use of syscall.ForkLock. Change-Id: Ie325da7c2397b5995db4a5ddb0117e2ce1745187 Reviewed-on: https://go-review.googlesource.com/72010 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
392 lines
10 KiB
Go
392 lines
10 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package os
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import (
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"internal/poll"
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"internal/syscall/windows"
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"runtime"
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"syscall"
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"unicode/utf16"
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"unsafe"
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)
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// file is the real representation of *File.
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// The extra level of indirection ensures that no clients of os
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// can overwrite this data, which could cause the finalizer
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// to close the wrong file descriptor.
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type file struct {
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pfd poll.FD
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name string
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dirinfo *dirInfo // nil unless directory being read
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}
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// Fd returns the Windows handle referencing the open file.
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// The handle is valid only until f.Close is called or f is garbage collected.
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func (file *File) Fd() uintptr {
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if file == nil {
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return uintptr(syscall.InvalidHandle)
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}
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return uintptr(file.pfd.Sysfd)
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}
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// newFile returns a new File with the given file handle and name.
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// Unlike NewFile, it does not check that h is syscall.InvalidHandle.
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func newFile(h syscall.Handle, name string, kind string) *File {
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if kind == "file" {
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var m uint32
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if syscall.GetConsoleMode(h, &m) == nil {
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kind = "console"
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}
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}
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f := &File{&file{
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pfd: poll.FD{
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Sysfd: h,
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IsStream: true,
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ZeroReadIsEOF: true,
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},
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name: name,
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}}
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runtime.SetFinalizer(f.file, (*file).close)
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// Ignore initialization errors.
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// Assume any problems will show up in later I/O.
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f.pfd.Init(kind, false)
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return f
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}
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// newConsoleFile creates new File that will be used as console.
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func newConsoleFile(h syscall.Handle, name string) *File {
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return newFile(h, name, "console")
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}
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// NewFile returns a new File with the given file descriptor and
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// name. The returned value will be nil if fd is not a valid file
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// descriptor.
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func NewFile(fd uintptr, name string) *File {
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h := syscall.Handle(fd)
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if h == syscall.InvalidHandle {
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return nil
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}
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return newFile(h, name, "file")
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}
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// Auxiliary information if the File describes a directory
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type dirInfo struct {
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data syscall.Win32finddata
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needdata bool
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path string
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isempty bool // set if FindFirstFile returns ERROR_FILE_NOT_FOUND
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}
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func epipecheck(file *File, e error) {
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}
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const DevNull = "NUL"
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func (f *file) isdir() bool { return f != nil && f.dirinfo != nil }
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func openFile(name string, flag int, perm FileMode) (file *File, err error) {
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r, e := syscall.Open(fixLongPath(name), flag|syscall.O_CLOEXEC, syscallMode(perm))
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if e != nil {
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return nil, e
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}
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return newFile(r, name, "file"), nil
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}
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func openDir(name string) (file *File, err error) {
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var mask string
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path := fixLongPath(name)
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if len(path) == 2 && path[1] == ':' || (len(path) > 0 && path[len(path)-1] == '\\') { // it is a drive letter, like C:
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mask = path + `*`
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} else {
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mask = path + `\*`
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}
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maskp, e := syscall.UTF16PtrFromString(mask)
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if e != nil {
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return nil, e
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}
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d := new(dirInfo)
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r, e := syscall.FindFirstFile(maskp, &d.data)
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if e != nil {
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// FindFirstFile returns ERROR_FILE_NOT_FOUND when
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// no matching files can be found. Then, if directory
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// exists, we should proceed.
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if e != syscall.ERROR_FILE_NOT_FOUND {
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return nil, e
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}
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var fa syscall.Win32FileAttributeData
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pathp, e := syscall.UTF16PtrFromString(path)
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if e != nil {
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return nil, e
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}
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e = syscall.GetFileAttributesEx(pathp, syscall.GetFileExInfoStandard, (*byte)(unsafe.Pointer(&fa)))
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if e != nil {
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return nil, e
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}
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if fa.FileAttributes&syscall.FILE_ATTRIBUTE_DIRECTORY == 0 {
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return nil, e
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}
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d.isempty = true
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}
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d.path = path
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if !isAbs(d.path) {
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d.path, e = syscall.FullPath(d.path)
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if e != nil {
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return nil, e
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}
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}
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f := newFile(r, name, "dir")
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f.dirinfo = d
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return f, nil
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}
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// OpenFile is the generalized open call; most users will use Open
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// or Create instead. It opens the named file with specified flag
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// (O_RDONLY etc.) and perm, (0666 etc.) if applicable. If successful,
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// methods on the returned File can be used for I/O.
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// If there is an error, it will be of type *PathError.
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func OpenFile(name string, flag int, perm FileMode) (*File, error) {
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if name == "" {
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return nil, &PathError{"open", name, syscall.ENOENT}
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}
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r, errf := openFile(name, flag, perm)
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if errf == nil {
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return r, nil
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}
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r, errd := openDir(name)
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if errd == nil {
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if flag&O_WRONLY != 0 || flag&O_RDWR != 0 {
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r.Close()
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return nil, &PathError{"open", name, syscall.EISDIR}
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}
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return r, nil
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}
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return nil, &PathError{"open", name, errf}
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}
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// Close closes the File, rendering it unusable for I/O.
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// It returns an error, if any.
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func (file *File) Close() error {
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if file == nil {
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return ErrInvalid
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}
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return file.file.close()
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}
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func (file *file) close() error {
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if file == nil {
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return syscall.EINVAL
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}
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if file.isdir() && file.dirinfo.isempty {
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// "special" empty directories
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return nil
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}
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var err error
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if e := file.pfd.Close(); e != nil {
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if e == poll.ErrFileClosing {
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e = ErrClosed
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}
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err = &PathError{"close", file.name, e}
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}
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// no need for a finalizer anymore
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runtime.SetFinalizer(file, nil)
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return err
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}
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// read reads up to len(b) bytes from the File.
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// It returns the number of bytes read and an error, if any.
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func (f *File) read(b []byte) (n int, err error) {
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n, err = f.pfd.Read(b)
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runtime.KeepAlive(f)
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return n, err
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}
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// pread reads len(b) bytes from the File starting at byte offset off.
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// It returns the number of bytes read and the error, if any.
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// EOF is signaled by a zero count with err set to 0.
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func (f *File) pread(b []byte, off int64) (n int, err error) {
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n, err = f.pfd.Pread(b, off)
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runtime.KeepAlive(f)
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return n, err
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}
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// write writes len(b) bytes to the File.
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// It returns the number of bytes written and an error, if any.
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func (f *File) write(b []byte) (n int, err error) {
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n, err = f.pfd.Write(b)
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runtime.KeepAlive(f)
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return n, err
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}
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// pwrite writes len(b) bytes to the File starting at byte offset off.
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// It returns the number of bytes written and an error, if any.
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func (f *File) pwrite(b []byte, off int64) (n int, err error) {
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n, err = f.pfd.Pwrite(b, off)
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runtime.KeepAlive(f)
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return n, err
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}
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// seek sets the offset for the next Read or Write on file to offset, interpreted
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// according to whence: 0 means relative to the origin of the file, 1 means
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// relative to the current offset, and 2 means relative to the end.
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// It returns the new offset and an error, if any.
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func (f *File) seek(offset int64, whence int) (ret int64, err error) {
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ret, err = f.pfd.Seek(offset, whence)
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runtime.KeepAlive(f)
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return ret, err
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}
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// Truncate changes the size of the named file.
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// If the file is a symbolic link, it changes the size of the link's target.
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func Truncate(name string, size int64) error {
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f, e := OpenFile(name, O_WRONLY|O_CREATE, 0666)
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if e != nil {
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return e
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}
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defer f.Close()
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e1 := f.Truncate(size)
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if e1 != nil {
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return e1
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}
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return nil
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}
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// Remove removes the named file or directory.
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// If there is an error, it will be of type *PathError.
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func Remove(name string) error {
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p, e := syscall.UTF16PtrFromString(fixLongPath(name))
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if e != nil {
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return &PathError{"remove", name, e}
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}
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// Go file interface forces us to know whether
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// name is a file or directory. Try both.
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e = syscall.DeleteFile(p)
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if e == nil {
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return nil
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}
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e1 := syscall.RemoveDirectory(p)
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if e1 == nil {
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return nil
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}
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// Both failed: figure out which error to return.
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if e1 != e {
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a, e2 := syscall.GetFileAttributes(p)
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if e2 != nil {
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e = e2
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} else {
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if a&syscall.FILE_ATTRIBUTE_DIRECTORY != 0 {
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e = e1
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} else if a&syscall.FILE_ATTRIBUTE_READONLY != 0 {
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if e1 = syscall.SetFileAttributes(p, a&^syscall.FILE_ATTRIBUTE_READONLY); e1 == nil {
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if e = syscall.DeleteFile(p); e == nil {
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return nil
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}
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}
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}
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}
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}
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return &PathError{"remove", name, e}
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}
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func rename(oldname, newname string) error {
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e := windows.Rename(fixLongPath(oldname), fixLongPath(newname))
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if e != nil {
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return &LinkError{"rename", oldname, newname, e}
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}
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return nil
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}
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// Pipe returns a connected pair of Files; reads from r return bytes written to w.
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// It returns the files and an error, if any.
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func Pipe() (r *File, w *File, err error) {
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var p [2]syscall.Handle
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e := syscall.CreatePipe(&p[0], &p[1], nil, 0)
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if e != nil {
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return nil, nil, NewSyscallError("pipe", e)
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}
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return newFile(p[0], "|0", "file"), newFile(p[1], "|1", "file"), nil
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}
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func tempDir() string {
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n := uint32(syscall.MAX_PATH)
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for {
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b := make([]uint16, n)
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n, _ = syscall.GetTempPath(uint32(len(b)), &b[0])
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if n > uint32(len(b)) {
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continue
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}
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if n > 0 && b[n-1] == '\\' {
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n--
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}
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return string(utf16.Decode(b[:n]))
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}
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}
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// Link creates newname as a hard link to the oldname file.
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// If there is an error, it will be of type *LinkError.
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func Link(oldname, newname string) error {
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n, err := syscall.UTF16PtrFromString(fixLongPath(newname))
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if err != nil {
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return &LinkError{"link", oldname, newname, err}
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}
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o, err := syscall.UTF16PtrFromString(fixLongPath(oldname))
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if err != nil {
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return &LinkError{"link", oldname, newname, err}
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}
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err = syscall.CreateHardLink(n, o, 0)
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if err != nil {
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return &LinkError{"link", oldname, newname, err}
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}
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return nil
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}
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// Symlink creates newname as a symbolic link to oldname.
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// If there is an error, it will be of type *LinkError.
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func Symlink(oldname, newname string) error {
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// CreateSymbolicLink is not supported before Windows Vista
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if syscall.LoadCreateSymbolicLink() != nil {
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return &LinkError{"symlink", oldname, newname, syscall.EWINDOWS}
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}
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// '/' does not work in link's content
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oldname = fromSlash(oldname)
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// need the exact location of the oldname when its relative to determine if its a directory
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destpath := oldname
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if !isAbs(oldname) {
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destpath = dirname(newname) + `\` + oldname
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}
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fi, err := Lstat(destpath)
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isdir := err == nil && fi.IsDir()
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n, err := syscall.UTF16PtrFromString(fixLongPath(newname))
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if err != nil {
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return &LinkError{"symlink", oldname, newname, err}
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}
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o, err := syscall.UTF16PtrFromString(fixLongPath(oldname))
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if err != nil {
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return &LinkError{"symlink", oldname, newname, err}
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}
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var flags uint32
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if isdir {
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flags |= syscall.SYMBOLIC_LINK_FLAG_DIRECTORY
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}
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err = syscall.CreateSymbolicLink(n, o, flags)
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if err != nil {
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return &LinkError{"symlink", oldname, newname, err}
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}
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return nil
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}
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