154 lines
3.7 KiB
Go
154 lines
3.7 KiB
Go
// Copyright 2018 The Hugo Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package hugofs
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import (
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"errors"
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"os"
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"path/filepath"
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"github.com/gohugoio/hugo/common/loggers"
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"github.com/spf13/afero"
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)
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var ErrPermissionSymlink = errors.New("symlinks not allowed in this filesystem")
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// NewNoSymlinkFs creates a new filesystem that prevents symlinks.
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func NewNoSymlinkFs(fs afero.Fs, logger loggers.Logger, allowFiles bool) afero.Fs {
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return &noSymlinkFs{Fs: fs, logger: logger, allowFiles: allowFiles}
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}
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// noSymlinkFs is a filesystem that prevents symlinking.
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type noSymlinkFs struct {
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allowFiles bool // block dirs only
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logger loggers.Logger
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afero.Fs
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}
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type noSymlinkFile struct {
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fs *noSymlinkFs
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afero.File
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}
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func (f *noSymlinkFile) Readdir(count int) ([]os.FileInfo, error) {
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fis, err := f.File.Readdir(count)
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filtered := fis[:0]
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for _, x := range fis {
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filename := filepath.Join(f.Name(), x.Name())
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if _, err := f.fs.checkSymlinkStatus(filename, x); err != nil {
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// Log a warning and drop the file from the list
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logUnsupportedSymlink(filename, f.fs.logger)
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} else {
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filtered = append(filtered, x)
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}
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}
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return filtered, err
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}
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func (f *noSymlinkFile) Readdirnames(count int) ([]string, error) {
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dirs, err := f.Readdir(count)
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if err != nil {
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return nil, err
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}
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return fileInfosToNames(dirs), nil
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}
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func (fs *noSymlinkFs) LstatIfPossible(name string) (os.FileInfo, bool, error) {
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return fs.stat(name)
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}
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func (fs *noSymlinkFs) Stat(name string) (os.FileInfo, error) {
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fi, _, err := fs.stat(name)
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return fi, err
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}
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func (fs *noSymlinkFs) stat(name string) (os.FileInfo, bool, error) {
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var (
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fi os.FileInfo
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wasLstat bool
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err error
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)
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if lstater, ok := fs.Fs.(afero.Lstater); ok {
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fi, wasLstat, err = lstater.LstatIfPossible(name)
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} else {
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fi, err = fs.Fs.Stat(name)
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}
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if err != nil {
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return nil, false, err
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}
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fi, err = fs.checkSymlinkStatus(name, fi)
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return fi, wasLstat, err
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}
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func (fs *noSymlinkFs) checkSymlinkStatus(name string, fi os.FileInfo) (os.FileInfo, error) {
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var metaIsSymlink bool
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if fim, ok := fi.(FileMetaInfo); ok {
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meta := fim.Meta()
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metaIsSymlink = meta.IsSymlink()
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}
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if metaIsSymlink {
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if fs.allowFiles && !fi.IsDir() {
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return fi, nil
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}
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return nil, ErrPermissionSymlink
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}
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// Also support non-decorated filesystems, e.g. the Os fs.
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if isSymlink(fi) {
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// Need to determine if this is a directory or not.
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_, sfi, err := evalSymlinks(fs.Fs, name)
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if err != nil {
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return nil, err
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}
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if fs.allowFiles && !sfi.IsDir() {
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// Return the original FileInfo to get the expected Name.
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return fi, nil
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}
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return nil, ErrPermissionSymlink
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}
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return fi, nil
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}
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func (fs *noSymlinkFs) Open(name string) (afero.File, error) {
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if _, _, err := fs.stat(name); err != nil {
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return nil, err
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}
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return fs.wrapFile(fs.Fs.Open(name))
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}
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func (fs *noSymlinkFs) OpenFile(name string, flag int, perm os.FileMode) (afero.File, error) {
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if _, _, err := fs.stat(name); err != nil {
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return nil, err
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}
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return fs.wrapFile(fs.Fs.OpenFile(name, flag, perm))
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}
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func (fs *noSymlinkFs) wrapFile(f afero.File, err error) (afero.File, error) {
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if err != nil {
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return nil, err
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}
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return &noSymlinkFile{File: f, fs: fs}, nil
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}
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