250 lines
7 KiB
Go
250 lines
7 KiB
Go
// 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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//go:build aix || darwin || dragonfly || freebsd || hurd || (js && wasm) || linux || netbsd || openbsd || solaris || windows
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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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"time"
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)
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func sigpipe() // implemented in package runtime
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// Close closes the File, rendering it unusable for I/O.
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// On files that support SetDeadline, any pending I/O operations will
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// be canceled and return immediately with an ErrClosed error.
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// Close will return an error if it has already been called.
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func (f *File) Close() error {
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if f == nil {
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return ErrInvalid
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}
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return f.file.close()
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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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n, err = f.pfd.Read(b)
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runtime.KeepAlive(f)
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return n, err
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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 nil.
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func (f *File) pread(b []byte, off int64) (n int, err error) {
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n, err = f.pfd.Pread(b, off)
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runtime.KeepAlive(f)
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return n, err
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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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n, err = f.pfd.Write(b)
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runtime.KeepAlive(f)
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return n, err
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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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n, err = f.pfd.Pwrite(b, off)
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runtime.KeepAlive(f)
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return n, err
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}
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// syscallMode returns the syscall-specific mode bits from Go's portable mode bits.
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func syscallMode(i FileMode) (o uint32) {
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o |= uint32(i.Perm())
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if i&ModeSetuid != 0 {
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o |= syscall.S_ISUID
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}
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if i&ModeSetgid != 0 {
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o |= syscall.S_ISGID
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}
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if i&ModeSticky != 0 {
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o |= syscall.S_ISVTX
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}
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// No mapping for Go's ModeTemporary (plan9 only).
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return
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}
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// See docs in file.go:Chmod.
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func chmod(name string, mode FileMode) error {
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longName := fixLongPath(name)
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e := ignoringEINTR(func() error {
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return syscall.Chmod(longName, syscallMode(mode))
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})
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if e != nil {
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return &PathError{Op: "chmod", Path: name, Err: e}
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}
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return nil
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}
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// See docs in file.go:(*File).Chmod.
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func (f *File) chmod(mode FileMode) error {
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if err := f.checkValid("chmod"); err != nil {
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return err
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}
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if e := f.pfd.Fchmod(syscallMode(mode)); e != nil {
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return f.wrapErr("chmod", e)
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}
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return nil
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}
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// Chown changes the numeric uid and gid of the named file.
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// If the file is a symbolic link, it changes the uid and gid of the link's target.
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// A uid or gid of -1 means to not change that value.
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// If there is an error, it will be of type *PathError.
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//
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// On Windows or Plan 9, Chown always returns the syscall.EWINDOWS or
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// EPLAN9 error, wrapped in *PathError.
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func Chown(name string, uid, gid int) error {
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e := ignoringEINTR(func() error {
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return syscall.Chown(name, uid, gid)
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})
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if e != nil {
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return &PathError{Op: "chown", Path: name, Err: e}
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}
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return nil
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}
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// Lchown changes the numeric uid and gid of the named file.
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// If the file is a symbolic link, it changes the uid and gid of the link itself.
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// If there is an error, it will be of type *PathError.
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//
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// On Windows, it always returns the syscall.EWINDOWS error, wrapped
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// in *PathError.
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func Lchown(name string, uid, gid int) error {
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e := ignoringEINTR(func() error {
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return syscall.Lchown(name, uid, gid)
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})
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if e != nil {
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return &PathError{Op: "lchown", Path: name, Err: e}
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}
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return nil
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}
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// Chown changes the numeric uid and gid of the named file.
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// If there is an error, it will be of type *PathError.
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//
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// On Windows, it always returns the syscall.EWINDOWS error, wrapped
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// in *PathError.
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func (f *File) Chown(uid, gid int) error {
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if err := f.checkValid("chown"); err != nil {
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return err
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}
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if e := f.pfd.Fchown(uid, gid); e != nil {
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return f.wrapErr("chown", e)
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}
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return nil
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}
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// Truncate changes the size of the file.
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// It does not change the I/O offset.
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// If there is an error, it will be of type *PathError.
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func (f *File) Truncate(size int64) error {
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if err := f.checkValid("truncate"); err != nil {
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return err
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}
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if e := f.pfd.Ftruncate(size); e != nil {
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return f.wrapErr("truncate", e)
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}
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return nil
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}
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// Sync commits the current contents of the file to stable storage.
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// Typically, this means flushing the file system's in-memory copy
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// of recently written data to disk.
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func (f *File) Sync() error {
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if err := f.checkValid("sync"); err != nil {
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return err
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}
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if e := f.pfd.Fsync(); e != nil {
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return f.wrapErr("sync", e)
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}
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return nil
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}
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// Chtimes changes the access and modification times of the named
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// file, similar to the Unix utime() or utimes() functions.
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//
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// The underlying filesystem may truncate or round the values to a
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// less precise time unit.
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// If there is an error, it will be of type *PathError.
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func Chtimes(name string, atime time.Time, mtime time.Time) error {
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var utimes [2]syscall.Timespec
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utimes[0] = syscall.NsecToTimespec(atime.UnixNano())
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utimes[1] = syscall.NsecToTimespec(mtime.UnixNano())
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if e := syscall.UtimesNano(fixLongPath(name), utimes[0:]); e != nil {
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return &PathError{Op: "chtimes", Path: name, Err: e}
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}
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return nil
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}
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// Chdir changes the current working directory to the file,
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// which must be a directory.
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// If there is an error, it will be of type *PathError.
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func (f *File) Chdir() error {
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if err := f.checkValid("chdir"); err != nil {
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return err
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}
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if e := f.pfd.Fchdir(); e != nil {
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return f.wrapErr("chdir", e)
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}
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return nil
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}
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// setDeadline sets the read and write deadline.
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func (f *File) setDeadline(t time.Time) error {
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if err := f.checkValid("SetDeadline"); err != nil {
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return err
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}
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return f.pfd.SetDeadline(t)
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}
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// setReadDeadline sets the read deadline.
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func (f *File) setReadDeadline(t time.Time) error {
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if err := f.checkValid("SetReadDeadline"); err != nil {
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return err
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}
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return f.pfd.SetReadDeadline(t)
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}
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// setWriteDeadline sets the write deadline.
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func (f *File) setWriteDeadline(t time.Time) error {
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if err := f.checkValid("SetWriteDeadline"); err != nil {
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return err
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}
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return f.pfd.SetWriteDeadline(t)
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}
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// checkValid checks whether f is valid for use.
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// If not, it returns an appropriate error, perhaps incorporating the operation name op.
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func (f *File) checkValid(op string) error {
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if f == nil {
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return ErrInvalid
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}
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return nil
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}
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// ignoringEINTR makes a function call and repeats it if it returns an
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// EINTR error. This appears to be required even though we install all
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// signal handlers with SA_RESTART: see #22838, #38033, #38836, #40846.
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// Also #20400 and #36644 are issues in which a signal handler is
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// installed without setting SA_RESTART. None of these are the common case,
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// but there are enough of them that it seems that we can't avoid
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// an EINTR loop.
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func ignoringEINTR(fn func() error) error {
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for {
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err := fn()
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if err != syscall.EINTR {
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return err
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}
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}
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}
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