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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgo/] [go/] [os/] [file_unix.go] - Blame information for rev 774

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Line No. Rev Author Line
1 747 jeremybenn
// 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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// +build darwin freebsd linux netbsd openbsd
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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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// File represents an open file descriptor.
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type File struct {
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        *file
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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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        fd      int
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        name    string
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        dirinfo *dirInfo // nil unless directory being read
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        nepipe  int      // number of consecutive EPIPE in Write
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}
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// Fd returns the integer Unix file descriptor referencing the open file.
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func (f *File) Fd() int {
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        if f == nil {
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                return -1
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        }
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        return f.fd
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}
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// NewFile returns a new File with the given file descriptor and name.
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func NewFile(fd int, name string) *File {
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        if fd < 0 {
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                return nil
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        }
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        f := &File{&file{fd: fd, name: name}}
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        runtime.SetFinalizer(f.file, (*file).close)
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        return f
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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 []byte       // buffer for directory I/O
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        dir *syscall.DIR // from opendir
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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 FileMode) (file *File, err error) {
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        r, e := syscall.Open(name, flag|syscall.O_CLOEXEC, syscallMode(perm))
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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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        // There's a race here with fork/exec, which we are
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        // content to live with.  See ../syscall/exec_unix.go.
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        // On OS X 10.6, the O_CLOEXEC flag is not respected.
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        // On OS X 10.7, the O_CLOEXEC flag works.
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        // Without a cheap & reliable way to detect 10.6 vs 10.7 at
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        // runtime, we just always call syscall.CloseOnExec on Darwin.
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        // Once >=10.7 is prevalent, this extra call can removed.
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        if syscall.O_CLOEXEC == 0 || runtime.GOOS == "darwin" { // O_CLOEXEC not supported
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                syscall.CloseOnExec(r)
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        }
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        return NewFile(r, 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 (f *File) Close() error {
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        return f.file.close()
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}
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func (file *file) close() error {
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        if file == nil || file.fd < 0 {
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                return EINVAL
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        }
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        var err error
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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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        if file.dirinfo != nil {
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                if libc_closedir(file.dirinfo.dir) < 0 && err == nil {
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                        err = &PathError{"closedir", file.name, syscall.GetErrno()}
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                }
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        }
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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 (f *File) Stat() (fi FileInfo, err error) {
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        var stat syscall.Stat_t
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        err = syscall.Fstat(f.fd, &stat)
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        if err != nil {
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                return nil, &PathError{"stat", f.name, err}
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        }
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        return fileInfoFromStat(&stat, f.name), nil
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}
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// Stat returns a FileInfo describing the named file and an error, if any.
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// If name names a valid symbolic link, the returned FileInfo describes
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// the file pointed at by the link and has fi.FollowedSymlink set to true.
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// If name names an invalid symbolic link, the returned FileInfo describes
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// the link itself and has fi.FollowedSymlink set to false.
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func Stat(name string) (fi FileInfo, err error) {
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        var stat syscall.Stat_t
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        err = syscall.Stat(name, &stat)
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        if err != nil {
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                return nil, &PathError{"stat", name, err}
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        }
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        return fileInfoFromStat(&stat, name), nil
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}
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// Lstat returns a FileInfo describing the named file and an
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// error, if any.  If the file is a symbolic link, the returned FileInfo
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// describes the symbolic link.  Lstat makes no attempt to follow the link.
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func Lstat(name string) (fi FileInfo, err error) {
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        var stat syscall.Stat_t
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        err = syscall.Lstat(name, &stat)
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        if err != nil {
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                return nil, &PathError{"lstat", name, err}
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        }
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        return fileInfoFromStat(&stat, name), nil
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}
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func (f *File) readdir(n int) (fi []FileInfo, err error) {
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        dirname := f.name
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        if dirname == "" {
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                dirname = "."
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        }
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        dirname += "/"
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        names, err := f.Readdirnames(n)
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        fi = make([]FileInfo, len(names))
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        for i, filename := range names {
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                fip, err := Lstat(dirname + filename)
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                if err == nil {
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                        fi[i] = fip
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                } else {
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                        fi[i] = &fileStat{name: filename}
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                }
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        }
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        return fi, 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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        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 0.
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func (f *File) pread(b []byte, off int64) (n int, err 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 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 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 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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        if e := syscall.Truncate(name, size); e != nil {
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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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        // System call interface forces us to know
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        // whether name is a file or directory.
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        // Try both: it is cheaper on average than
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        // doing a Stat plus the right one.
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        e := syscall.Unlink(name)
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        if e == nil {
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                return nil
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        }
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        e1 := syscall.Rmdir(name)
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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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        // OS X and Linux differ on whether unlink(dir)
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        // returns EISDIR, so can't use that.  However,
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        // both agree that rmdir(file) returns ENOTDIR,
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        // so we can use that to decide which error is real.
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        // Rmdir might also return ENOTDIR if given a bad
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        // file path, like /etc/passwd/foo, but in that case,
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        // both errors will be ENOTDIR, so it's okay to
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        // use the error from unlink.
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        if e1 != syscall.ENOTDIR {
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                e = e1
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        }
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        return &PathError{"remove", name, e}
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}
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// basename removes trailing slashes and the leading directory name from path name
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func basename(name string) string {
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        i := len(name) - 1
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        // Remove trailing slashes
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        for ; i > 0 && name[i] == '/'; i-- {
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                name = name[:i]
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        }
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        // Remove leading directory name
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        for i--; i >= 0; i-- {
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                if name[i] == '/' {
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                        name = name[i+1:]
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                        break
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                }
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        }
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        return name
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}
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// Pipe returns a connected pair of Files; reads from r return bytes written to w.
258
// It returns the files and an error, if any.
259
func Pipe() (r *File, w *File, err error) {
260
        var p [2]int
261
 
262
        // See ../syscall/exec.go for description of lock.
263
        syscall.ForkLock.RLock()
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        e := syscall.Pipe(p[0:])
265
        if e != nil {
266
                syscall.ForkLock.RUnlock()
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                return nil, nil, NewSyscallError("pipe", e)
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        }
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        syscall.CloseOnExec(p[0])
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        syscall.CloseOnExec(p[1])
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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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// TempDir returns the default directory to use for temporary files.
277
func TempDir() string {
278
        dir := Getenv("TMPDIR")
279
        if dir == "" {
280
                dir = "/tmp"
281
        }
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        return dir
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}

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