285 lines
8.1 KiB
Go
285 lines
8.1 KiB
Go
// 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 freebsd linux netbsd openbsd
|
|
|
|
package os
|
|
|
|
import (
|
|
"runtime"
|
|
"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 int // number of consecutive EPIPE in Write
|
|
}
|
|
|
|
// Fd returns the integer Unix file descriptor referencing the open file.
|
|
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
|
|
dir *syscall.DIR // from opendir
|
|
}
|
|
|
|
// 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.
|
|
// On OS X 10.6, the O_CLOEXEC flag is not respected.
|
|
// On OS X 10.7, the O_CLOEXEC flag works.
|
|
// Without a cheap & reliable way to detect 10.6 vs 10.7 at
|
|
// runtime, we just always call syscall.CloseOnExec on Darwin.
|
|
// Once >=10.7 is prevalent, this extra call can removed.
|
|
if syscall.O_CLOEXEC == 0 || runtime.GOOS == "darwin" { // O_CLOEXEC not supported
|
|
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 {
|
|
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}
|
|
}
|
|
|
|
if file.dirinfo != nil {
|
|
if libc_closedir(file.dirinfo.dir) < 0 && err == nil {
|
|
err = &PathError{"closedir", file.name, syscall.GetErrno()}
|
|
}
|
|
}
|
|
|
|
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) {
|
|
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 = "."
|
|
}
|
|
dirname += "/"
|
|
names, err := f.Readdirnames(n)
|
|
fi = make([]FileInfo, len(names))
|
|
for i, filename := range names {
|
|
fip, err := Lstat(dirname + filename)
|
|
if err == nil {
|
|
fi[i] = fip
|
|
} else {
|
|
fi[i] = &fileStat{name: filename}
|
|
}
|
|
}
|
|
return fi, err
|
|
}
|
|
|
|
// 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 0.
|
|
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 {
|
|
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
|
|
}
|
|
|
|
// 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
|
|
|
|
// See ../syscall/exec.go for description of lock.
|
|
syscall.ForkLock.RLock()
|
|
e := syscall.Pipe(p[0:])
|
|
if e != nil {
|
|
syscall.ForkLock.RUnlock()
|
|
return nil, nil, NewSyscallError("pipe", e)
|
|
}
|
|
syscall.CloseOnExec(p[0])
|
|
syscall.CloseOnExec(p[1])
|
|
syscall.ForkLock.RUnlock()
|
|
|
|
return NewFile(uintptr(p[0]), "|0"), NewFile(uintptr(p[1]), "|1"), nil
|
|
}
|
|
|
|
// TempDir returns the default directory to use for temporary files.
|
|
func TempDir() string {
|
|
dir := Getenv("TMPDIR")
|
|
if dir == "" {
|
|
dir = "/tmp"
|
|
}
|
|
return dir
|
|
}
|