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- // 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.
- //go:build aix || darwin || dragonfly || freebsd || hurd || (js && wasm) || linux || netbsd || openbsd || solaris
- package os
- import (
- "internal/poll"
- "internal/syscall/unix"
- "runtime"
- "syscall"
- )
- // fixLongPath is a noop on non-Windows platforms.
- func fixLongPath(path string) string {
- return path
- }
- func rename(oldname, newname string) error {
- fi, err := Lstat(newname)
- if err == nil && fi.IsDir() {
- // There are two independent errors this function can return:
- // one for a bad oldname, and one for a bad newname.
- // At this point we've determined the newname is bad.
- // But just in case oldname is also bad, prioritize returning
- // the oldname error because that's what we did historically.
- // However, if the old name and new name are not the same, yet
- // they refer to the same file, it implies a case-only
- // rename on a case-insensitive filesystem, which is ok.
- if ofi, err := Lstat(oldname); err != nil {
- if pe, ok := err.(*PathError); ok {
- err = pe.Err
- }
- return &LinkError{"rename", oldname, newname, err}
- } else if newname == oldname || !SameFile(fi, ofi) {
- return &LinkError{"rename", oldname, newname, syscall.EEXIST}
- }
- }
- err = ignoringEINTR(func() error {
- return syscall.Rename(oldname, newname)
- })
- if err != nil {
- return &LinkError{"rename", oldname, newname, err}
- }
- return nil
- }
- // 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 {
- pfd poll.FD
- name string
- dirinfo *dirInfo // nil unless directory being read
- nonblock bool // whether we set nonblocking mode
- stdoutOrErr bool // whether this is stdout or stderr
- appendMode bool // whether file is opened for appending
- }
- // Fd returns the integer Unix file descriptor referencing the open file.
- // If f is closed, the file descriptor becomes invalid.
- // If f is garbage collected, a finalizer may close the file descriptor,
- // making it invalid; see runtime.SetFinalizer for more information on when
- // a finalizer might be run. On Unix systems this will cause the SetDeadline
- // methods to stop working.
- // Because file descriptors can be reused, the returned file descriptor may
- // only be closed through the Close method of f, or by its finalizer during
- // garbage collection. Otherwise, during garbage collection the finalizer
- // may close an unrelated file descriptor with the same (reused) number.
- //
- // As an alternative, see the f.SyscallConn method.
- func (f *File) Fd() uintptr {
- if f == nil {
- return ^(uintptr(0))
- }
- // If we put the file descriptor into nonblocking mode,
- // then set it to blocking mode before we return it,
- // because historically we have always returned a descriptor
- // opened in blocking mode. The File will continue to work,
- // but any blocking operation will tie up a thread.
- if f.nonblock {
- f.pfd.SetBlocking()
- }
- return uintptr(f.pfd.Sysfd)
- }
- // NewFile returns a new File with the given file descriptor and
- // name. The returned value will be nil if fd is not a valid file
- // descriptor. On Unix systems, if the file descriptor is in
- // non-blocking mode, NewFile will attempt to return a pollable File
- // (one for which the SetDeadline methods work).
- //
- // After passing it to NewFile, fd may become invalid under the same
- // conditions described in the comments of the Fd method, and the same
- // constraints apply.
- func NewFile(fd uintptr, name string) *File {
- kind := kindNewFile
- if nb, err := unix.IsNonblock(int(fd)); err == nil && nb {
- kind = kindNonBlock
- }
- return newFile(fd, name, kind)
- }
- // newFileKind describes the kind of file to newFile.
- type newFileKind int
- const (
- kindNewFile newFileKind = iota
- kindOpenFile
- kindPipe
- kindNonBlock
- )
- // newFile is like NewFile, but if called from OpenFile or Pipe
- // (as passed in the kind parameter) it tries to add the file to
- // the runtime poller.
- func newFile(fd uintptr, name string, kind newFileKind) *File {
- fdi := int(fd)
- if fdi < 0 {
- return nil
- }
- f := &File{&file{
- pfd: poll.FD{
- Sysfd: fdi,
- IsStream: true,
- ZeroReadIsEOF: true,
- },
- name: name,
- stdoutOrErr: fdi == 1 || fdi == 2,
- }}
- pollable := kind == kindOpenFile || kind == kindPipe || kind == kindNonBlock
- // If the caller passed a non-blocking filedes (kindNonBlock),
- // we assume they know what they are doing so we allow it to be
- // used with kqueue.
- if kind == kindOpenFile {
- switch runtime.GOOS {
- case "darwin", "ios", "dragonfly", "freebsd", "netbsd", "openbsd":
- var st syscall.Stat_t
- err := ignoringEINTR(func() error {
- return syscall.Fstat(fdi, &st)
- })
- typ := st.Mode & syscall.S_IFMT
- // Don't try to use kqueue with regular files on *BSDs.
- // On FreeBSD a regular file is always
- // reported as ready for writing.
- // On Dragonfly, NetBSD and OpenBSD the fd is signaled
- // only once as ready (both read and write).
- // Issue 19093.
- // Also don't add directories to the netpoller.
- if err == nil && (typ == syscall.S_IFREG || typ == syscall.S_IFDIR) {
- pollable = false
- }
- // In addition to the behavior described above for regular files,
- // on Darwin, kqueue does not work properly with fifos:
- // closing the last writer does not cause a kqueue event
- // for any readers. See issue #24164.
- if (runtime.GOOS == "darwin" || runtime.GOOS == "ios") && typ == syscall.S_IFIFO {
- pollable = false
- }
- }
- }
- if err := f.pfd.Init("file", pollable); err != nil {
- // An error here indicates a failure to register
- // with the netpoll system. That can happen for
- // a file descriptor that is not supported by
- // epoll/kqueue; for example, disk files on
- // Linux systems. We assume that any real error
- // will show up in later I/O.
- } else if pollable {
- // We successfully registered with netpoll, so put
- // the file into nonblocking mode.
- if err := syscall.SetNonblock(fdi, true); err == nil {
- f.nonblock = true
- }
- }
- runtime.SetFinalizer(f.file, (*file).close)
- return f
- }
- // Auxiliary information if the File describes a directory
- type dirInfo struct {
- dir *syscall.DIR // from opendir
- }
- func (d *dirInfo) close() {
- if d.dir != nil {
- syscall.Entersyscall()
- libc_closedir(d.dir)
- syscall.Exitsyscall()
- d.dir = nil
- }
- }
- // epipecheck raises SIGPIPE if we get an EPIPE error on standard
- // output or standard error. See the SIGPIPE docs in os/signal, and
- // issue 11845.
- func epipecheck(file *File, e error) {
- if e == syscall.EPIPE && file.stdoutOrErr {
- sigpipe()
- }
- }
- // 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"
- // openFileNolog is the Unix implementation of OpenFile.
- // Changes here should be reflected in openFdAt, if relevant.
- func openFileNolog(name string, flag int, perm FileMode) (*File, error) {
- setSticky := false
- if !supportsCreateWithStickyBit && flag&O_CREATE != 0 && perm&ModeSticky != 0 {
- if _, err := Stat(name); IsNotExist(err) {
- setSticky = true
- }
- }
- var r int
- for {
- var e error
- r, e = syscall.Open(name, flag|syscall.O_CLOEXEC, syscallMode(perm))
- if e == nil {
- break
- }
- // We have to check EINTR here, per issues 11180 and 39237.
- if e == syscall.EINTR {
- continue
- }
- return nil, &PathError{Op: "open", Path: name, Err: e}
- }
- // open(2) itself won't handle the sticky bit on *BSD and Solaris
- if setSticky {
- setStickyBit(name)
- }
- // 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, kindOpenFile), nil
- }
- func (file *file) close() error {
- if file == nil {
- return syscall.EINVAL
- }
- var err error
- if file.dirinfo != nil {
- file.dirinfo.close()
- file.dirinfo = nil
- }
- if e := file.pfd.Close(); e != nil {
- if e == poll.ErrFileClosing {
- e = ErrClosed
- }
- err = &PathError{Op: "close", Path: file.name, Err: e}
- }
- // no need for a finalizer anymore
- runtime.SetFinalizer(file, nil)
- return err
- }
- // 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) {
- if f.dirinfo != nil {
- // Free cached dirinfo, so we allocate a new one if we
- // access this file as a directory again. See #35767 and #37161.
- f.dirinfo.close()
- f.dirinfo = nil
- }
- ret, err = f.pfd.Seek(offset, whence)
- runtime.KeepAlive(f)
- return ret, err
- }
- // 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 {
- e := ignoringEINTR(func() error {
- return syscall.Truncate(name, size)
- })
- if e != nil {
- return &PathError{Op: "truncate", Path: name, Err: e}
- }
- return nil
- }
- // Remove removes the named file or (empty) 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 := ignoringEINTR(func() error {
- return syscall.Unlink(name)
- })
- if e == nil {
- return nil
- }
- e1 := ignoringEINTR(func() error {
- return 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{Op: "remove", Path: name, Err: e}
- }
- 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 := ignoringEINTR(func() error {
- return syscall.Link(oldname, newname)
- })
- if e != nil {
- return &LinkError{"link", oldname, newname, e}
- }
- return nil
- }
- // Symlink creates newname as a symbolic link to oldname.
- // On Windows, a symlink to a non-existent oldname creates a file symlink;
- // if oldname is later created as a directory the symlink will not work.
- // If there is an error, it will be of type *LinkError.
- func Symlink(oldname, newname string) error {
- e := ignoringEINTR(func() error {
- return syscall.Symlink(oldname, newname)
- })
- if e != nil {
- return &LinkError{"symlink", oldname, newname, e}
- }
- return nil
- }
- // 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) {
- for len := 128; ; len *= 2 {
- b := make([]byte, len)
- var (
- n int
- e error
- )
- for {
- n, e = fixCount(syscall.Readlink(name, b))
- if e != syscall.EINTR {
- break
- }
- }
- // buffer too small
- if runtime.GOOS == "aix" && e == syscall.ERANGE {
- continue
- }
- if e != nil {
- return "", &PathError{Op: "readlink", Path: name, Err: e}
- }
- if n < len {
- return string(b[0:n]), nil
- }
- }
- }
- type unixDirent struct {
- parent string
- name string
- typ FileMode
- info FileInfo
- }
- func (d *unixDirent) Name() string { return d.name }
- func (d *unixDirent) IsDir() bool { return d.typ.IsDir() }
- func (d *unixDirent) Type() FileMode { return d.typ }
- func (d *unixDirent) Info() (FileInfo, error) {
- if d.info != nil {
- return d.info, nil
- }
- return lstat(d.parent + "/" + d.name)
- }
- func newUnixDirent(parent, name string, typ FileMode) (DirEntry, error) {
- ude := &unixDirent{
- parent: parent,
- name: name,
- typ: typ,
- }
- if typ != ^FileMode(0) && !testingForceReadDirLstat {
- return ude, nil
- }
- info, err := lstat(parent + "/" + name)
- if err != nil {
- return nil, err
- }
- ude.typ = info.Mode().Type()
- ude.info = info
- return ude, nil
- }
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