mirror of
https://github.com/golang/go
synced 2024-10-05 04:21:22 -06:00
b1deb3be7f
R=bradfitzgo, rsc, peterGo CC=golang-dev https://golang.org/cl/4441051
274 lines
6.7 KiB
Go
274 lines
6.7 KiB
Go
// Copyright 2011 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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"runtime"
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"syscall"
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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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buf [syscall.STATMAX]byte // buffer for directory I/O
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nbuf int // length of buf; return value from Read
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bufp int // location of next record in buf.
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}
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func epipecheck(file *File, e syscall.Error) {
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}
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// DevNull is the name of the operating system's ``null device.''
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// On Unix-like systems, it is "/dev/null"; on Windows, "NUL".
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const DevNull = "/dev/null"
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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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// It returns the File and an Error, if any.
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func OpenFile(name string, flag int, perm uint32) (file *File, err Error) {
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var fd int
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var e syscall.Error
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syscall.ForkLock.RLock()
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if flag&O_CREATE == O_CREATE {
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fd, e = syscall.Create(name, flag & ^O_CREATE, perm)
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} else {
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fd, e = syscall.Open(name, flag)
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}
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syscall.ForkLock.RUnlock()
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if e != nil {
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return nil, &PathError{"open", name, e}
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}
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return NewFile(fd, name), nil
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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 || file.fd < 0 {
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return Ebadfd
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}
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var err Error
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syscall.ForkLock.RLock()
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if e := syscall.Close(file.fd); e != nil {
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err = &PathError{"close", file.name, e}
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}
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syscall.ForkLock.RUnlock()
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file.fd = -1 // so it can't be closed again
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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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// Stat returns the FileInfo structure describing file.
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// It returns the FileInfo and an error, if any.
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func (file *File) Stat() (fi *FileInfo, err Error) {
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return dirstat(file)
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}
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// Truncate changes the size of the file.
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// It does not change the I/O offset.
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func (f *File) Truncate(size int64) Error {
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var d Dir
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d.Null()
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d.Length = uint64(size)
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if e := syscall.Fwstat(f.fd, pdir(nil, &d)); iserror(e) {
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return &PathError{"truncate", f.name, e}
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}
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return nil
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}
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// Chmod changes the mode of the file to mode.
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func (f *File) Chmod(mode uint32) Error {
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var d Dir
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d.Null()
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d.Mode = mode & 0777
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if e := syscall.Fwstat(f.fd, pdir(nil, &d)); iserror(e) {
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return &PathError{"chmod", f.name, e}
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}
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return nil
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}
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// Sync commits the current contents of the file to stable storage.
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// Typically, this means flushing the file system's in-memory copy
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// of recently written data to disk.
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func (f *File) Sync() (err Error) {
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if f == nil {
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return EINVAL
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}
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var d Dir
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d.Null()
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if e := syscall.Fwstat(f.fd, pdir(nil, &d)); iserror(e) {
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return NewSyscallError("fsync", e)
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}
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return nil
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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 syscall.Error) {
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return syscall.Read(f.fd, b)
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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 nil.
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func (f *File) pread(b []byte, off int64) (n int, err syscall.Error) {
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return syscall.Pread(f.fd, b, off)
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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 syscall.Error) {
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return syscall.Write(f.fd, b)
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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 syscall.Error) {
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return syscall.Pwrite(f.fd, b, off)
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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 syscall.Error) {
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return syscall.Seek(f.fd, offset, whence)
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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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var d Dir
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d.Null()
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d.Length = uint64(size)
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if e := syscall.Wstat(name, pdir(nil, &d)); iserror(e) {
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return &PathError{"truncate", name, e}
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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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func Remove(name string) Error {
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if e := syscall.Remove(name); iserror(e) {
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return &PathError{"remove", name, e}
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}
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return nil
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}
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// Rename renames a file.
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func Rename(oldname, newname string) Error {
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var d Dir
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d.Null()
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d.Name = newname
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if e := syscall.Wstat(oldname, pdir(nil, &d)); iserror(e) {
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return &PathError{"rename", oldname, e}
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}
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return nil
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}
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// Chmod changes the mode of the named file to mode.
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func Chmod(name string, mode uint32) Error {
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var d Dir
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d.Null()
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d.Mode = mode & 0777
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if e := syscall.Wstat(name, pdir(nil, &d)); iserror(e) {
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return &PathError{"chmod", name, e}
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}
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return nil
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}
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// ChownPlan9 changes the uid and gid strings of the named file.
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func ChownPlan9(name, uid, gid string) Error {
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var d Dir
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d.Null()
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d.Uid = uid
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d.Gid = gid
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if e := syscall.Wstat(name, pdir(nil, &d)); iserror(e) {
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return &PathError{"chown_plan9", name, e}
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}
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return nil
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}
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// Chtimes changes the access and modification times of the named
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// file, similar to the Unix utime() or utimes() functions.
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//
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// The argument times are in nanoseconds, although the underlying
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// filesystem may truncate or round the values to a more
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// coarse time unit.
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func Chtimes(name string, atimeNs int64, mtimeNs int64) Error {
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var d Dir
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d.Null()
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d.Atime = uint32(atimeNs / 1e9)
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d.Mtime = uint32(mtimeNs / 1e9)
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if e := syscall.Wstat(name, pdir(nil, &d)); iserror(e) {
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return &PathError{"chtimes", name, e}
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}
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return nil
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}
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func Pipe() (r *File, w *File, err Error) {
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var p [2]int
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syscall.ForkLock.RLock()
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if e := syscall.Pipe(p[0:]); iserror(e) {
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syscall.ForkLock.RUnlock()
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return nil, nil, NewSyscallError("pipe", e)
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}
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syscall.ForkLock.RUnlock()
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return NewFile(p[0], "|0"), NewFile(p[1], "|1"), nil
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}
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// not supported on Plan 9
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// Link creates a hard link.
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func Link(oldname, newname string) Error {
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return EPLAN9
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}
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func Symlink(oldname, newname string) Error {
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return EPLAN9
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}
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func Readlink(name string) (string, Error) {
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return "", EPLAN9
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}
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func Chown(name string, uid, gid int) Error {
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return EPLAN9
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}
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func Lchown(name string, uid, gid int) Error {
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return EPLAN9
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}
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func (f *File) Chown(uid, gid int) Error {
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return EPLAN9
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}
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