Imported Upstream version 1.4upstream/1.4

1 files changed, 339 insertions, 0 deletions

diff --git a/src/os/file_unix.go b/src/os/file_unix.go
new file mode 100644
index 000000000..ff4fc7d12
--- /dev/null
+++ b/src/os/file_unix.go
@@ -0,0 +1,339 @@
+// Copyright 2009 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.
+
+// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris
+
+package os
+
+import (
+	"runtime"
+	"sync/atomic"
+	"syscall"
+)
+
+// 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
+	nepipe  int32    // number of consecutive EPIPE in Write
+}
+
+// Fd returns the integer Unix 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  []byte // buffer for directory I/O
+	nbuf int    // length of buf; return value from Getdirentries
+	bufp int    // location of next record in buf.
+}
+
+func epipecheck(file *File, e error) {
+	if e == syscall.EPIPE {
+		if atomic.AddInt32(&file.nepipe, 1) >= 10 {
+			sigpipe()
+		}
+	} else {
+		atomic.StoreInt32(&file.nepipe, 0)
+	}
+}
+
+// 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"
+
+// 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) {
+	r, e := syscall.Open(name, flag|syscall.O_CLOEXEC, syscallMode(perm))
+	if e != nil {
+		return nil, &PathError{"open", name, e}
+	}
+
+	// There's a race here with fork/exec, which we are
+	// content to live with.  See ../syscall/exec_unix.go.
+	if !supportsCloseOnExec {
+		syscall.CloseOnExec(r)
+	}
+
+	return NewFile(uintptr(r), 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 syscall.EINVAL
+	}
+	var err error
+	if e := syscall.Close(file.fd); e != nil {
+		err = &PathError{"close", file.name, e}
+	}
+	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
+	}
+	var stat syscall.Stat_t
+	err = syscall.Fstat(f.fd, &stat)
+	if err != nil {
+		return nil, &PathError{"stat", f.name, err}
+	}
+	return fileInfoFromStat(&stat, f.name), nil
+}
+
+// Stat returns a FileInfo describing the named file.
+// If there is an error, it will be of type *PathError.
+func Stat(name string) (fi FileInfo, err error) {
+	var stat syscall.Stat_t
+	err = syscall.Stat(name, &stat)
+	if err != nil {
+		return nil, &PathError{"stat", name, err}
+	}
+	return fileInfoFromStat(&stat, name), nil
+}
+
+// Lstat returns a FileInfo describing the named file.
+// If the file is a symbolic link, the returned FileInfo
+// describes the symbolic link.  Lstat makes no attempt to follow the link.
+// If there is an error, it will be of type *PathError.
+func Lstat(name string) (fi FileInfo, err error) {
+	var stat syscall.Stat_t
+	err = syscall.Lstat(name, &stat)
+	if err != nil {
+		return nil, &PathError{"lstat", name, err}
+	}
+	return fileInfoFromStat(&stat, name), nil
+}
+
+func (f *File) readdir(n int) (fi []FileInfo, err error) {
+	dirname := f.name
+	if dirname == "" {
+		dirname = "."
+	}
+	names, err := f.Readdirnames(n)
+	fi = make([]FileInfo, 0, len(names))
+	for _, filename := range names {
+		fip, lerr := lstat(dirname + "/" + filename)
+		if IsNotExist(lerr) {
+			// File disappeared between readdir + stat.
+			// Just treat it as if it didn't exist.
+			continue
+		}
+		if lerr != nil {
+			return fi, lerr
+		}
+		fi = append(fi, fip)
+	}
+	return fi, err
+}
+
+// Darwin and FreeBSD can't read or write 2GB+ at a time,
+// even on 64-bit systems. See golang.org/issue/7812.
+// Use 1GB instead of, say, 2GB-1, to keep subsequent
+// reads aligned.
+const (
+	needsMaxRW = runtime.GOOS == "darwin" || runtime.GOOS == "freebsd"
+	maxRW      = 1 << 30
+)
+
+// 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) {
+	if needsMaxRW && len(b) > maxRW {
+		b = b[:maxRW]
+	}
+	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) {
+	if needsMaxRW && len(b) > maxRW {
+		b = b[:maxRW]
+	}
+	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.
+func (f *File) write(b []byte) (n int, err error) {
+	for {
+		bcap := b
+		if needsMaxRW && len(bcap) > maxRW {
+			bcap = bcap[:maxRW]
+		}
+		m, err := fixCount(syscall.Write(f.fd, bcap))
+		n += m
+
+		// If the syscall wrote some data but not all (short write)
+		// or it returned EINTR, then assume it stopped early for
+		// reasons that are uninteresting to the caller, and try again.
+		if 0 < m && m < len(bcap) || err == syscall.EINTR {
+			b = b[m:]
+			continue
+		}
+
+		if needsMaxRW && len(bcap) != len(b) && err == nil {
+			b = b[m:]
+			continue
+		}
+
+		return n, err
+	}
+}
+
+// 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) {
+	if needsMaxRW && len(b) > maxRW {
+		b = b[:maxRW]
+	}
+	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 {
+	if e := syscall.Truncate(name, size); 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 {
+	// System call interface forces us to know
+	// whether name is a file or directory.
+	// Try both: it is cheaper on average than
+	// doing a Stat plus the right one.
+	e := syscall.Unlink(name)
+	if e == nil {
+		return nil
+	}
+	e1 := syscall.Rmdir(name)
+	if e1 == nil {
+		return nil
+	}
+
+	// Both failed: figure out which error to return.
+	// OS X and Linux differ on whether unlink(dir)
+	// returns EISDIR, so can't use that.  However,
+	// both agree that rmdir(file) returns ENOTDIR,
+	// so we can use that to decide which error is real.
+	// Rmdir might also return ENOTDIR if given a bad
+	// file path, like /etc/passwd/foo, but in that case,
+	// both errors will be ENOTDIR, so it's okay to
+	// use the error from unlink.
+	if e1 != syscall.ENOTDIR {
+		e = e1
+	}
+	return &PathError{"remove", name, e}
+}
+
+// basename removes trailing slashes and the leading directory name from path name
+func basename(name string) string {
+	i := len(name) - 1
+	// Remove trailing slashes
+	for ; i > 0 && name[i] == '/'; i-- {
+		name = name[:i]
+	}
+	// Remove leading directory name
+	for i--; i >= 0; i-- {
+		if name[i] == '/' {
+			name = name[i+1:]
+			break
+		}
+	}
+
+	return name
+}
+
+// TempDir returns the default directory to use for temporary files.
+func TempDir() string {
+	dir := Getenv("TMPDIR")
+	if dir == "" {
+		if runtime.GOOS == "android" {
+			dir = "/data/local/tmp"
+		} else {
+			dir = "/tmp"
+		}
+	}
+	return dir
+}
+
+// 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 {
+	e := syscall.Link(oldname, newname)
+	if e != nil {
+		return &LinkError{"link", oldname, newname, e}
+	}
+	return nil
+}
+
+// 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 {
+	e := syscall.Symlink(oldname, newname)
+	if e != nil {
+		return &LinkError{"symlink", oldname, newname, e}
+	}
+	return nil
+}