Imported Upstream version 1.4upstream/1.4

1 files changed, 469 insertions, 0 deletions

diff --git a/src/os/file_plan9.go b/src/os/file_plan9.go
new file mode 100644
index 000000000..132594eed
--- /dev/null
+++ b/src/os/file_plan9.go
@@ -0,0 +1,469 @@
+// 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 Plan 9 file descriptor referencing the open file.
+// The file descriptor is valid only until f.Close is called or f is garbage collected.
+func (f *File) Fd() uintptr {
+	if f == nil {
+		return ^(uintptr(0))
+	}
+	return uintptr(f.fd)
+}
+
+// NewFile returns a new File with the given file descriptor and name.
+func NewFile(fd uintptr, name string) *File {
+	fdi := int(fd)
+	if fdi < 0 {
+		return nil
+	}
+	f := &File{&file{fd: fdi, 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
+	}
+
+	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
+			}
+		}
+	}
+
+	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(uintptr(fd), name), nil
+}
+
+// Close closes the File, rendering it unusable for I/O.
+// It returns an error, if any.
+func (f *File) Close() error {
+	if f == nil {
+		return ErrInvalid
+	}
+	return f.file.close()
+}
+
+func (file *file) close() error {
+	if file == nil || file.fd < 0 {
+		return ErrInvalid
+	}
+	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.
+// If there is an error, it will be of type *PathError.
+func (f *File) Stat() (fi FileInfo, err error) {
+	if f == nil {
+		return nil, ErrInvalid
+	}
+	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.
+// If there is an error, it will be of type *PathError.
+func (f *File) Truncate(size int64) error {
+	if f == nil {
+		return ErrInvalid
+	}
+
+	var d syscall.Dir
+	d.Null()
+	d.Length = size
+
+	var buf [syscall.STATFIXLEN]byte
+	n, err := d.Marshal(buf[:])
+	if err != nil {
+		return &PathError{"truncate", f.name, err}
+	}
+	if err = syscall.Fwstat(f.fd, buf[:n]); err != nil {
+		return &PathError{"truncate", f.name, err}
+	}
+	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 {
+	if f == nil {
+		return ErrInvalid
+	}
+	var d syscall.Dir
+
+	odir, e := dirstat(f)
+	if e != nil {
+		return &PathError{"chmod", f.name, e}
+	}
+	d.Null()
+	d.Mode = odir.Mode&^chmodMask | syscallMode(mode)&chmodMask
+
+	var buf [syscall.STATFIXLEN]byte
+	n, err := d.Marshal(buf[:])
+	if err != nil {
+		return &PathError{"chmod", f.name, err}
+	}
+	if err = syscall.Fwstat(f.fd, buf[:n]); err != nil {
+		return &PathError{"chmod", f.name, err}
+	}
+	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 ErrInvalid
+	}
+	var d syscall.Dir
+	d.Null()
+
+	var buf [syscall.STATFIXLEN]byte
+	n, err := d.Marshal(buf[:])
+	if err != nil {
+		return NewSyscallError("fsync", err)
+	}
+	if err = syscall.Fwstat(f.fd, buf[:n]); err != nil {
+		return NewSyscallError("fsync", err)
+	}
+	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 fixCount(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 fixCount(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.
+// Since Plan 9 preserves message boundaries, never allow
+// a zero-byte write.
+func (f *File) write(b []byte) (n int, err error) {
+	if len(b) == 0 {
+		return 0, nil
+	}
+	return fixCount(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.
+// Since Plan 9 preserves message boundaries, never allow
+// a zero-byte write.
+func (f *File) pwrite(b []byte, off int64) (n int, err error) {
+	if len(b) == 0 {
+		return 0, nil
+	}
+	return fixCount(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 syscall.Dir
+
+	d.Null()
+	d.Length = size
+
+	var buf [syscall.STATFIXLEN]byte
+	n, err := d.Marshal(buf[:])
+	if err != nil {
+		return &PathError{"truncate", name, err}
+	}
+	if err = syscall.Wstat(name, buf[:n]); err != nil {
+		return &PathError{"truncate", name, err}
+	}
+	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
+}
+
+// HasPrefix from the strings package.
+func hasPrefix(s, prefix string) bool {
+	return len(s) >= len(prefix) && s[0:len(prefix)] == prefix
+}
+
+// Variant of LastIndex from the strings package.
+func lastIndex(s string, sep byte) int {
+	for i := len(s) - 1; i >= 0; i-- {
+		if s[i] == sep {
+			return i
+		}
+	}
+	return -1
+}
+
+func rename(oldname, newname string) error {
+	dirname := oldname[:lastIndex(oldname, '/')+1]
+	if hasPrefix(newname, dirname) {
+		newname = newname[len(dirname):]
+	} else {
+		return &LinkError{"rename", oldname, newname, ErrInvalid}
+	}
+
+	// If newname still contains slashes after removing the oldname
+	// prefix, the rename is cross-directory and must be rejected.
+	// This case is caught by d.Marshal below.
+
+	var d syscall.Dir
+
+	d.Null()
+	d.Name = newname
+
+	buf := make([]byte, syscall.STATFIXLEN+len(d.Name))
+	n, err := d.Marshal(buf[:])
+	if err != nil {
+		return &LinkError{"rename", oldname, newname, err}
+	}
+	if err = syscall.Wstat(oldname, buf[:n]); err != nil {
+		return &LinkError{"rename", oldname, newname, err}
+	}
+	return nil
+}
+
+// Chmod changes the mode of the named file to mode.
+// If the file is a symbolic link, it changes the mode of the link's target.
+// If there is an error, it will be of type *PathError.
+func Chmod(name string, mode FileMode) error {
+	var d syscall.Dir
+
+	odir, e := dirstat(name)
+	if e != nil {
+		return &PathError{"chmod", name, e}
+	}
+	d.Null()
+	d.Mode = odir.Mode&^chmodMask | syscallMode(mode)&chmodMask
+
+	var buf [syscall.STATFIXLEN]byte
+	n, err := d.Marshal(buf[:])
+	if err != nil {
+		return &PathError{"chmod", name, err}
+	}
+	if err = syscall.Wstat(name, buf[:n]); err != nil {
+		return &PathError{"chmod", name, err}
+	}
+	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.
+// If there is an error, it will be of type *PathError.
+func Chtimes(name string, atime time.Time, mtime time.Time) error {
+	var d syscall.Dir
+
+	d.Null()
+	d.Atime = uint32(atime.Unix())
+	d.Mtime = uint32(mtime.Unix())
+
+	var buf [syscall.STATFIXLEN]byte
+	n, err := d.Marshal(buf[:])
+	if err != nil {
+		return &PathError{"chtimes", name, err}
+	}
+	if err = syscall.Wstat(name, buf[:n]); err != nil {
+		return &PathError{"chtimes", name, err}
+	}
+	return nil
+}
+
+// Pipe returns a connected pair of Files; reads from r return bytes
+// written to w. It returns the files and an error, if any.
+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(uintptr(p[0]), "|0"), NewFile(uintptr(p[1]), "|1"), nil
+}
+
+// not supported on Plan 9
+
+// Link creates newname as a hard link to the oldname file.
+// If there is an error, it will be of type *LinkError.
+func Link(oldname, newname string) error {
+	return &LinkError{"link", oldname, newname, syscall.EPLAN9}
+}
+
+// Symlink creates newname as a symbolic link to oldname.
+// If there is an error, it will be of type *LinkError.
+func Symlink(oldname, newname string) error {
+	return &LinkError{"symlink", oldname, newname, syscall.EPLAN9}
+}
+
+// Readlink returns the destination of the named symbolic link.
+// If there is an error, it will be of type *PathError.
+func Readlink(name string) (string, error) {
+	return "", &PathError{"readlink", name, syscall.EPLAN9}
+}
+
+// Chown changes the numeric uid and gid of the named file.
+// If the file is a symbolic link, it changes the uid and gid of the link's target.
+// If there is an error, it will be of type *PathError.
+func Chown(name string, uid, gid int) error {
+	return &PathError{"chown", name, syscall.EPLAN9}
+}
+
+// Lchown changes the numeric uid and gid of the named file.
+// If the file is a symbolic link, it changes the uid and gid of the link itself.
+// If there is an error, it will be of type *PathError.
+func Lchown(name string, uid, gid int) error {
+	return &PathError{"lchown", name, syscall.EPLAN9}
+}
+
+// Chown changes the numeric uid and gid of the named file.
+// If there is an error, it will be of type *PathError.
+func (f *File) Chown(uid, gid int) error {
+	if f == nil {
+		return ErrInvalid
+	}
+	return &PathError{"chown", f.name, syscall.EPLAN9}
+}
+
+// TempDir returns the default directory to use for temporary files.
+func TempDir() string {
+	return "/tmp"
+}