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// Copyright 2018 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 unix
package os
import (
"internal/syscall/unix"
"io"
"syscall"
)
func removeAll(path string) error {
if path == "" {
// fail silently to retain compatibility with previous behavior
// of RemoveAll. See issue 28830.
return nil
}
// The rmdir system call does not permit removing ".",
// so we don't permit it either.
if endsWithDot(path) {
return &PathError{Op: "RemoveAll", Path: path, Err: syscall.EINVAL}
}
// Simple case: if Remove works, we're done.
err := Remove(path)
if err == nil || IsNotExist(err) {
return nil
}
// RemoveAll recurses by deleting the path base from
// its parent directory
parentDir, base := splitPath(path)
parent, err := Open(parentDir)
if IsNotExist(err) {
// If parent does not exist, base cannot exist. Fail silently
return nil
}
if err != nil {
return err
}
defer parent.Close()
if err := removeAllFrom(parent, base); err != nil {
if pathErr, ok := err.(*PathError); ok {
pathErr.Path = parentDir + string(PathSeparator) + pathErr.Path
err = pathErr
}
return err
}
return nil
}
func removeAllFrom(parent *File, base string) error {
parentFd := int(parent.Fd())
// Simple case: if Unlink (aka remove) works, we're done.
err := unix.Unlinkat(parentFd, base, 0)
if err == nil || IsNotExist(err) {
return nil
}
// EISDIR means that we have a directory, and we need to
// remove its contents.
// EPERM or EACCES means that we don't have write permission on
// the parent directory, but this entry might still be a directory
// whose contents need to be removed.
// Otherwise just return the error.
if err != syscall.EISDIR && err != syscall.EPERM && err != syscall.EACCES {
return &PathError{Op: "unlinkat", Path: base, Err: err}
}
// Is this a directory we need to recurse into?
var statInfo syscall.Stat_t
statErr := unix.Fstatat(parentFd, base, &statInfo, unix.AT_SYMLINK_NOFOLLOW)
if statErr != nil {
if IsNotExist(statErr) {
return nil
}
return &PathError{Op: "fstatat", Path: base, Err: statErr}
}
if statInfo.Mode&syscall.S_IFMT != syscall.S_IFDIR {
// Not a directory; return the error from the unix.Unlinkat.
return &PathError{Op: "unlinkat", Path: base, Err: err}
}
// Remove the directory's entries.
var recurseErr error
for {
const reqSize = 1024
var respSize int
// Open the directory to recurse into
file, err := openFdAt(parentFd, base)
if err != nil {
if IsNotExist(err) {
return nil
}
recurseErr = &PathError{Op: "openfdat", Path: base, Err: err}
break
}
for {
numErr := 0
names, readErr := file.Readdirnames(reqSize)
// Errors other than EOF should stop us from continuing.
if readErr != nil && readErr != io.EOF {
file.Close()
if IsNotExist(readErr) {
return nil
}
return &PathError{Op: "readdirnames", Path: base, Err: readErr}
}
respSize = len(names)
for _, name := range names {
err := removeAllFrom(file, name)
if err != nil {
if pathErr, ok := err.(*PathError); ok {
pathErr.Path = base + string(PathSeparator) + pathErr.Path
}
numErr++
if recurseErr == nil {
recurseErr = err
}
}
}
// If we can delete any entry, break to start new iteration.
// Otherwise, we discard current names, get next entries and try deleting them.
if numErr != reqSize {
break
}
}
// Removing files from the directory may have caused
// the OS to reshuffle it. Simply calling Readdirnames
// again may skip some entries. The only reliable way
// to avoid this is to close and re-open the
// directory. See issue 20841.
file.Close()
// Finish when the end of the directory is reached
if respSize < reqSize {
break
}
}
// Remove the directory itself.
unlinkError := unix.Unlinkat(parentFd, base, unix.AT_REMOVEDIR)
if unlinkError == nil || IsNotExist(unlinkError) {
return nil
}
if recurseErr != nil {
return recurseErr
}
return &PathError{Op: "unlinkat", Path: base, Err: unlinkError}
}
// openFdAt opens path relative to the directory in fd.
// Other than that this should act like openFileNolog.
// This acts like openFileNolog rather than OpenFile because
// we are going to (try to) remove the file.
// The contents of this file are not relevant for test caching.
func openFdAt(dirfd int, name string) (*File, error) {
var r int
for {
var e error
r, e = unix.Openat(dirfd, name, O_RDONLY|syscall.O_CLOEXEC, 0)
if e == nil {
break
}
// See comment in openFileNolog.
if e == syscall.EINTR {
continue
}
return nil, e
}
if !supportsCloseOnExec {
syscall.CloseOnExec(r)
}
return newFile(uintptr(r), name, kindOpenFile), nil
}
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