src/pkg/os/file_plan9.go - go - Git at Google

 // Copyright 2011 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 package os

 import (
 	"runtime"
 	"syscall"
 	"time"
 )

 // File represents an open file descriptor.
 type File struct {
 	*file
 }

 // file is the real representation of *File.
 // The extra level of indirection ensures that no clients of os
 // can overwrite this data, which could cause the finalizer
 // to close the wrong file descriptor.
 type file struct {
 	fd      int
 	name    string
 	dirinfo *dirInfo // nil unless directory being read
 }

 // Fd returns the integer Unix file descriptor referencing the open file.
 func (file *File) Fd() int {
 	if file == nil {
 		return -1
 	}
 	return file.fd
 }

 // NewFile returns a new File with the given file descriptor and name.
 func NewFile(fd int, name string) *File {
 	if fd < 0 {
 		return nil
 	}
 	f := &File{&file{fd: fd, name: name}}
 	runtime.SetFinalizer(f.file, (*file).close)
 	return f
 }

 // Auxiliary information if the File describes a directory
 type dirInfo struct {
 	buf  [syscall.STATMAX]byte // buffer for directory I/O
 	nbuf int                   // length of buf; return value from Read
 	bufp int                   // location of next record in buf.
 }

 func epipecheck(file *File, e error) {
 }

 // DevNull is the name of the operating system's ``null device.''
 // On Unix-like systems, it is "/dev/null"; on Windows, "NUL".
 const DevNull = "/dev/null"

 // syscallMode returns the syscall-specific mode bits from Go's portable mode bits.
 func syscallMode(i FileMode) (o uint32) {
 	o |= uint32(i.Perm())
 	if i&ModeAppend != 0 {
 		o |= syscall.DMAPPEND
 	}
 	if i&ModeExclusive != 0 {
 		o |= syscall.DMEXCL
 	}
 	if i&ModeTemporary != 0 {
 		o |= syscall.DMTMP
 	}
 	return
 }

 // OpenFile is the generalized open call; most users will use Open
 // or Create instead.  It opens the named file with specified flag
 // (O_RDONLY etc.) and perm, (0666 etc.) if applicable.  If successful,
 // methods on the returned File can be used for I/O.
 // If there is an error, it will be of type *PathError.
 func OpenFile(name string, flag int, perm FileMode) (file *File, err error) {
 	var (
 		fd     int
 		e      error
 		create bool
 		excl   bool
 		trunc  bool
 		append bool
 	)

 	if flag&O_CREATE == O_CREATE {
 		flag = flag & ^O_CREATE
 		create = true
 	}
 	if flag&O_EXCL == O_EXCL {
 		excl = true
 	}
 	if flag&O_TRUNC == O_TRUNC {
 		trunc = true
 	}
 	// O_APPEND is emulated on Plan 9
 	if flag&O_APPEND == O_APPEND {
 		flag = flag &^ O_APPEND
 		append = true
 	}

 	syscall.ForkLock.RLock()
 	if (create && trunc) || excl {
 		fd, e = syscall.Create(name, flag, syscallMode(perm))
 	} else {
 		fd, e = syscall.Open(name, flag)
 		if e != nil && create {
 			var e1 error
 			fd, e1 = syscall.Create(name, flag, syscallMode(perm))
 			if e1 == nil {
 				e = nil
 			}
 		}
 	}
 	syscall.ForkLock.RUnlock()

 	if e != nil {
 		return nil, &PathError{"open", name, e}
 	}

 	if append {
 		if _, e = syscall.Seek(fd, 0, SEEK_END); e != nil {
 			return nil, &PathError{"seek", name, e}
 		}
 	}

 	return NewFile(fd, name), nil
 }

 // Close closes the File, rendering it unusable for I/O.
 // It returns an error, if any.
 func (file *File) Close() error {
 	return file.file.close()
 }

 func (file *file) close() error {
 	if file == nil || file.fd < 0 {
 		return Ebadfd
 	}
 	var err error
 	syscall.ForkLock.RLock()
 	if e := syscall.Close(file.fd); e != nil {
 		err = &PathError{"close", file.name, e}
 	}
 	syscall.ForkLock.RUnlock()
 	file.fd = -1 // so it can't be closed again

 	// no need for a finalizer anymore
 	runtime.SetFinalizer(file, nil)
 	return err
 }

 // Stat returns the FileInfo structure describing file.
 // It returns the FileInfo and an error, if any.
 func (f *File) Stat() (FileInfo, error) {
 	d, err := dirstat(f)
 	if err != nil {
 		return nil, err
 	}
 	return fileInfoFromStat(d), nil
 }

 // Truncate changes the size of the file.
 // It does not change the I/O offset.
 func (f *File) Truncate(size int64) error {
 	var d Dir
 	d.Null()

 	d.Length = uint64(size)

 	if e := syscall.Fwstat(f.fd, pdir(nil, &d)); e != nil {
 		return &PathError{"truncate", f.name, e}
 	}
 	return nil
 }

 const chmodMask = uint32(syscall.DMAPPEND | syscall.DMEXCL | syscall.DMTMP | ModePerm)

 // Chmod changes the mode of the file to mode.
 // If there is an error, it will be of type *PathError.
 func (f *File) Chmod(mode FileMode) error {
 	var d Dir

 	odir, e := dirstat(f)
 	if e != nil {
 		return &PathError{"chmod", f.name, e}
 	}
 	d.Null()
 	d.Mode = odir.Mode&^chmodMask | syscallMode(mode)&chmodMask
 	if e := syscall.Fwstat(f.fd, pdir(nil, &d)); e != nil {
 		return &PathError{"chmod", f.name, e}
 	}
 	return nil
 }

 // Sync commits the current contents of the file to stable storage.
 // Typically, this means flushing the file system's in-memory copy
 // of recently written data to disk.
 func (f *File) Sync() (err error) {
 	if f == nil {
 		return EINVAL
 	}

 	var d Dir
 	d.Null()

 	if e := syscall.Fwstat(f.fd, pdir(nil, &d)); e != nil {
 		return NewSyscallError("fsync", e)
 	}
 	return nil
 }

 // read reads up to len(b) bytes from the File.
 // It returns the number of bytes read and an error, if any.
 func (f *File) read(b []byte) (n int, err error) {
 	return syscall.Read(f.fd, b)
 }

 // pread reads len(b) bytes from the File starting at byte offset off.
 // It returns the number of bytes read and the error, if any.
 // EOF is signaled by a zero count with err set to nil.
 func (f *File) pread(b []byte, off int64) (n int, err error) {
 	return syscall.Pread(f.fd, b, off)
 }

 // write writes len(b) bytes to the File.
 // It returns the number of bytes written and an error, if any.
 func (f *File) write(b []byte) (n int, err error) {
 	return syscall.Write(f.fd, b)
 }

 // pwrite writes len(b) bytes to the File starting at byte offset off.
 // It returns the number of bytes written and an error, if any.
 func (f *File) pwrite(b []byte, off int64) (n int, err error) {
 	return syscall.Pwrite(f.fd, b, off)
 }

 // seek sets the offset for the next Read or Write on file to offset, interpreted
 // according to whence: 0 means relative to the origin of the file, 1 means
 // relative to the current offset, and 2 means relative to the end.
 // It returns the new offset and an error, if any.
 func (f *File) seek(offset int64, whence int) (ret int64, err error) {
 	return syscall.Seek(f.fd, offset, whence)
 }

 // Truncate changes the size of the named file.
 // If the file is a symbolic link, it changes the size of the link's target.
 // If there is an error, it will be of type *PathError.
 func Truncate(name string, size int64) error {
 	var d Dir
 	d.Null()

 	d.Length = uint64(size)

 	if e := syscall.Wstat(name, pdir(nil, &d)); e != nil {
 		return &PathError{"truncate", name, e}
 	}
 	return nil
 }

 // Remove removes the named file or directory.
 // If there is an error, it will be of type *PathError.
 func Remove(name string) error {
 	if e := syscall.Remove(name); e != nil {
 		return &PathError{"remove", name, e}
 	}
 	return nil
 }

 // Rename renames a file.
 // If there is an error, it will be of type *PathError.
 func Rename(oldname, newname string) error {
 	var d Dir
 	d.Null()

 	d.Name = newname

 	if e := syscall.Wstat(oldname, pdir(nil, &d)); e != nil {
 		return &PathError{"rename", oldname, e}
 	}
 	return nil
 }

 // Chmod changes the mode of the named file to mode.
 // If there is an error, it will be of type *PathError.
 func Chmod(name string, mode FileMode) error {
 	var d Dir

 	odir, e := dirstat(name)
 	if e != nil {
 		return &PathError{"chmod", name, e}
 	}
 	d.Null()
 	d.Mode = odir.Mode&^chmodMask | syscallMode(mode)&chmodMask
 	if e := syscall.Wstat(name, pdir(nil, &d)); e != nil {
 		return &PathError{"chmod", name, e}
 	}
 	return nil
 }

 // Chtimes changes the access and modification times of the named
 // file, similar to the Unix utime() or utimes() functions.
 //
 // The underlying filesystem may truncate or round the values to a
 // less precise time unit.
 func Chtimes(name string, atime time.Time, mtime time.Time) error {
 	var d Dir
 	d.Null()

 	d.Atime = uint32(atime.Unix())
 	d.Mtime = uint32(mtime.Unix())

 	if e := syscall.Wstat(name, pdir(nil, &d)); e != nil {
 		return &PathError{"chtimes", name, e}
 	}
 	return nil
 }

 func Pipe() (r *File, w *File, err error) {
 	var p [2]int

 	syscall.ForkLock.RLock()
 	if e := syscall.Pipe(p[0:]); e != nil {
 		syscall.ForkLock.RUnlock()
 		return nil, nil, NewSyscallError("pipe", e)
 	}
 	syscall.ForkLock.RUnlock()

 	return NewFile(p[0], "|0"), NewFile(p[1], "|1"), nil
 }

 // not supported on Plan 9

 // Link creates a hard link.
 func Link(oldname, newname string) error {
 	return EPLAN9
 }

 func Symlink(oldname, newname string) error {
 	return EPLAN9
 }

 func Readlink(name string) (string, error) {
 	return "", EPLAN9
 }

 func Chown(name string, uid, gid int) error {
 	return EPLAN9
 }

 func Lchown(name string, uid, gid int) error {
 	return EPLAN9
 }

 func (f *File) Chown(uid, gid int) error {
 	return EPLAN9
 }

 // TempDir returns the default directory to use for temporary files.
 func TempDir() string {
 	return "/tmp"
 }
	// Copyright 2011 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package os

	import (
	"runtime"
	"syscall"
	"time"
	)

	// File represents an open file descriptor.
	type File struct {
	*file
	}

	// file is the real representation of *File.
	// The extra level of indirection ensures that no clients of os
	// can overwrite this data, which could cause the finalizer
	// to close the wrong file descriptor.
	type file struct {
	fd int
	name string
	dirinfo *dirInfo // nil unless directory being read
	}

	// Fd returns the integer Unix file descriptor referencing the open file.
	func (file *File) Fd() int {
	if file == nil {
	return -1
	}
	return file.fd
	}

	// NewFile returns a new File with the given file descriptor and name.
	func NewFile(fd int, name string) *File {
	if fd < 0 {
	return nil
	}
	f := &File{&file{fd: fd, name: name}}
	runtime.SetFinalizer(f.file, (*file).close)
	return f
	}

	// Auxiliary information if the File describes a directory
	type dirInfo struct {
	buf [syscall.STATMAX]byte // buffer for directory I/O
	nbuf int // length of buf; return value from Read
	bufp int // location of next record in buf.
	}

	func epipecheck(file *File, e error) {
	}

	// DevNull is the name of the operating system's ``null device.''
	// On Unix-like systems, it is "/dev/null"; on Windows, "NUL".
	const DevNull = "/dev/null"

	// syscallMode returns the syscall-specific mode bits from Go's portable mode bits.
	func syscallMode(i FileMode) (o uint32) {
	o \|= uint32(i.Perm())
	if i&ModeAppend != 0 {
	o \|= syscall.DMAPPEND
	}
	if i&ModeExclusive != 0 {
	o \|= syscall.DMEXCL
	}
	if i&ModeTemporary != 0 {
	o \|= syscall.DMTMP
	}
	return
	}

	// OpenFile is the generalized open call; most users will use Open
	// or Create instead. It opens the named file with specified flag
	// (O_RDONLY etc.) and perm, (0666 etc.) if applicable. If successful,
	// methods on the returned File can be used for I/O.
	// If there is an error, it will be of type *PathError.
	func OpenFile(name string, flag int, perm FileMode) (file *File, err error) {
	var (
	fd int
	e error
	create bool
	excl bool
	trunc bool
	append bool
	)

	if flag&O_CREATE == O_CREATE {
	flag = flag & ^O_CREATE
	create = true
	}
	if flag&O_EXCL == O_EXCL {
	excl = true
	}
	if flag&O_TRUNC == O_TRUNC {
	trunc = true
	}
	// O_APPEND is emulated on Plan 9
	if flag&O_APPEND == O_APPEND {
	flag = flag &^ O_APPEND
	append = true
	}

	syscall.ForkLock.RLock()
	if (create && trunc) \|\| excl {
	fd, e = syscall.Create(name, flag, syscallMode(perm))
	} else {
	fd, e = syscall.Open(name, flag)
	if e != nil && create {
	var e1 error
	fd, e1 = syscall.Create(name, flag, syscallMode(perm))
	if e1 == nil {
	e = nil
	}
	}
	}
	syscall.ForkLock.RUnlock()

	if e != nil {
	return nil, &PathError{"open", name, e}
	}

	if append {
	if _, e = syscall.Seek(fd, 0, SEEK_END); e != nil {
	return nil, &PathError{"seek", name, e}
	}
	}

	return NewFile(fd, name), nil
	}

	// Close closes the File, rendering it unusable for I/O.
	// It returns an error, if any.
	func (file *File) Close() error {
	return file.file.close()
	}

	func (file *file) close() error {
	if file == nil \|\| file.fd < 0 {
	return Ebadfd
	}
	var err error
	syscall.ForkLock.RLock()
	if e := syscall.Close(file.fd); e != nil {
	err = &PathError{"close", file.name, e}
	}
	syscall.ForkLock.RUnlock()
	file.fd = -1 // so it can't be closed again

	// no need for a finalizer anymore
	runtime.SetFinalizer(file, nil)
	return err
	}

	// Stat returns the FileInfo structure describing file.
	// It returns the FileInfo and an error, if any.
	func (f *File) Stat() (FileInfo, error) {
	d, err := dirstat(f)
	if err != nil {
	return nil, err
	}
	return fileInfoFromStat(d), nil
	}

	// Truncate changes the size of the file.
	// It does not change the I/O offset.
	func (f *File) Truncate(size int64) error {
	var d Dir
	d.Null()

	d.Length = uint64(size)

	if e := syscall.Fwstat(f.fd, pdir(nil, &d)); e != nil {
	return &PathError{"truncate", f.name, e}
	}
	return nil
	}

	const chmodMask = uint32(syscall.DMAPPEND \| syscall.DMEXCL \| syscall.DMTMP \| ModePerm)

	// Chmod changes the mode of the file to mode.
	// If there is an error, it will be of type *PathError.
	func (f *File) Chmod(mode FileMode) error {
	var d Dir

	odir, e := dirstat(f)
	if e != nil {
	return &PathError{"chmod", f.name, e}
	}
	d.Null()
	d.Mode = odir.Mode&^chmodMask \| syscallMode(mode)&chmodMask
	if e := syscall.Fwstat(f.fd, pdir(nil, &d)); e != nil {
	return &PathError{"chmod", f.name, e}
	}
	return nil
	}

	// Sync commits the current contents of the file to stable storage.
	// Typically, this means flushing the file system's in-memory copy
	// of recently written data to disk.
	func (f *File) Sync() (err error) {
	if f == nil {
	return EINVAL
	}

	var d Dir
	d.Null()

	if e := syscall.Fwstat(f.fd, pdir(nil, &d)); e != nil {
	return NewSyscallError("fsync", e)
	}
	return nil
	}

	// read reads up to len(b) bytes from the File.
	// It returns the number of bytes read and an error, if any.
	func (f *File) read(b []byte) (n int, err error) {
	return syscall.Read(f.fd, b)
	}

	// pread reads len(b) bytes from the File starting at byte offset off.
	// It returns the number of bytes read and the error, if any.
	// EOF is signaled by a zero count with err set to nil.
	func (f *File) pread(b []byte, off int64) (n int, err error) {
	return syscall.Pread(f.fd, b, off)
	}

	// write writes len(b) bytes to the File.
	// It returns the number of bytes written and an error, if any.
	func (f *File) write(b []byte) (n int, err error) {
	return syscall.Write(f.fd, b)
	}

	// pwrite writes len(b) bytes to the File starting at byte offset off.
	// It returns the number of bytes written and an error, if any.
	func (f *File) pwrite(b []byte, off int64) (n int, err error) {
	return syscall.Pwrite(f.fd, b, off)
	}

	// seek sets the offset for the next Read or Write on file to offset, interpreted
	// according to whence: 0 means relative to the origin of the file, 1 means
	// relative to the current offset, and 2 means relative to the end.
	// It returns the new offset and an error, if any.
	func (f *File) seek(offset int64, whence int) (ret int64, err error) {
	return syscall.Seek(f.fd, offset, whence)
	}

	// Truncate changes the size of the named file.
	// If the file is a symbolic link, it changes the size of the link's target.
	// If there is an error, it will be of type *PathError.
	func Truncate(name string, size int64) error {
	var d Dir
	d.Null()

	d.Length = uint64(size)

	if e := syscall.Wstat(name, pdir(nil, &d)); e != nil {
	return &PathError{"truncate", name, e}
	}
	return nil
	}

	// Remove removes the named file or directory.
	// If there is an error, it will be of type *PathError.
	func Remove(name string) error {
	if e := syscall.Remove(name); e != nil {
	return &PathError{"remove", name, e}
	}
	return nil
	}

	// Rename renames a file.
	// If there is an error, it will be of type *PathError.
	func Rename(oldname, newname string) error {
	var d Dir
	d.Null()

	d.Name = newname

	if e := syscall.Wstat(oldname, pdir(nil, &d)); e != nil {
	return &PathError{"rename", oldname, e}
	}
	return nil
	}

	// Chmod changes the mode of the named file to mode.
	// If there is an error, it will be of type *PathError.
	func Chmod(name string, mode FileMode) error {
	var d Dir

	odir, e := dirstat(name)
	if e != nil {
	return &PathError{"chmod", name, e}
	}
	d.Null()
	d.Mode = odir.Mode&^chmodMask \| syscallMode(mode)&chmodMask
	if e := syscall.Wstat(name, pdir(nil, &d)); e != nil {
	return &PathError{"chmod", name, e}
	}
	return nil
	}

	// Chtimes changes the access and modification times of the named
	// file, similar to the Unix utime() or utimes() functions.
	//
	// The underlying filesystem may truncate or round the values to a
	// less precise time unit.
	func Chtimes(name string, atime time.Time, mtime time.Time) error {
	var d Dir
	d.Null()

	d.Atime = uint32(atime.Unix())
	d.Mtime = uint32(mtime.Unix())

	if e := syscall.Wstat(name, pdir(nil, &d)); e != nil {
	return &PathError{"chtimes", name, e}
	}
	return nil
	}

	func Pipe() (r File, w File, err error) {
	var p [2]int

	syscall.ForkLock.RLock()
	if e := syscall.Pipe(p[0:]); e != nil {
	syscall.ForkLock.RUnlock()
	return nil, nil, NewSyscallError("pipe", e)
	}
	syscall.ForkLock.RUnlock()

	return NewFile(p[0], "\|0"), NewFile(p[1], "\|1"), nil
	}

	// not supported on Plan 9

	// Link creates a hard link.
	func Link(oldname, newname string) error {
	return EPLAN9
	}

	func Symlink(oldname, newname string) error {
	return EPLAN9
	}

	func Readlink(name string) (string, error) {
	return "", EPLAN9
	}

	func Chown(name string, uid, gid int) error {
	return EPLAN9
	}

	func Lchown(name string, uid, gid int) error {
	return EPLAN9
	}

	func (f *File) Chown(uid, gid int) error {
	return EPLAN9
	}

	// TempDir returns the default directory to use for temporary files.
	func TempDir() string {
	return "/tmp"
	}