wings/internal/ufs/removeall_unix.go

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// SPDX-License-Identifier: BSD-3-Clause
// Code in this file was derived from `go/src/os/removeall_at.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 `go.LICENSE` file.
//go:build unix
package ufs
import (
"errors"
"io"
"os"
"golang.org/x/sys/unix"
)
type unixFS interface {
Open(name string) (File, error)
Remove(name string) error
unlinkat(dirfd int, path string, flags int) error
}
func (fs *UnixFS) removeAll(path string) error {
return removeAll(fs, path)
}
func removeAll(fs unixFS, path string) error {
if path == "" {
// fail silently to retain compatibility with previous behavior
// of RemoveAll. See issue https://go.dev/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: unix.EINVAL}
}
// Simple case: if Remove works, we're done.
err := fs.Remove(path)
if err == nil || errors.Is(err, ErrNotExist) {
return nil
}
// RemoveAll recurses by deleting the path base from
// its parent directory
parentDir, base := splitPath(path)
parent, err := fs.Open(parentDir)
if errors.Is(err, ErrNotExist) {
// If parent does not exist, base cannot exist. Fail silently
return nil
}
if err != nil {
return err
}
defer parent.Close()
if err := removeAllFrom(fs, parent, base); err != nil {
if pathErr, ok := err.(*PathError); ok {
pathErr.Path = parentDir + string(os.PathSeparator) + pathErr.Path
err = pathErr
}
return convertErrorType(err)
}
return nil
}
func removeAllFrom(fs unixFS, parent File, base string) error {
parentFd := int(parent.Fd())
// Simple case: if Unlink (aka remove) works, we're done.
err := fs.unlinkat(parentFd, base, 0)
if err == nil || errors.Is(err, ErrNotExist) {
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 != unix.EISDIR && err != unix.EPERM && err != unix.EACCES {
return &PathError{Op: "unlinkat", Path: base, Err: err}
}
// Is this a directory we need to recurse into?
var statInfo unix.Stat_t
statErr := ignoringEINTR(func() error {
return unix.Fstatat(parentFd, base, &statInfo, AT_SYMLINK_NOFOLLOW)
})
if statErr != nil {
if errors.Is(statErr, ErrNotExist) {
return nil
}
return &PathError{Op: "fstatat", Path: base, Err: statErr}
}
if statInfo.Mode&unix.S_IFMT != unix.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 errors.Is(err, ErrNotExist) {
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 errors.Is(readErr, ErrNotExist) {
return nil
}
return &PathError{Op: "readdirnames", Path: base, Err: readErr}
}
respSize = len(names)
for _, name := range names {
err := removeAllFrom(fs, file, name)
if err != nil {
if pathErr, ok := err.(*PathError); ok {
pathErr.Path = base + string(os.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 https://go.dev/issue/20841.
_ = file.Close()
// Finish when the end of the directory is reached
if respSize < reqSize {
break
}
}
// Remove the directory itself.
unlinkErr := fs.unlinkat(parentFd, base, AT_REMOVEDIR)
if unlinkErr == nil || errors.Is(unlinkErr, ErrNotExist) {
return nil
}
if recurseErr != nil {
return recurseErr
}
return &PathError{Op: "unlinkat", Path: base, Err: unlinkErr}
}
// 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 fd int
for {
var err error
fd, err = unix.Openat(dirfd, name, O_RDONLY|O_CLOEXEC|O_NOFOLLOW, 0)
if err == nil {
break
}
// See comment in openFileNolog.
if err == unix.EINTR {
continue
}
return nil, err
}
// This is stupid, os.NewFile immediately casts `fd` to an `int`, but wants
// it to be passed as a `uintptr`.
return os.NewFile(uintptr(fd), name), nil
}