wings/server/filesystem/filesystem.go

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package filesystem
import (
"bufio"
"emperror.dev/errors"
"github.com/gabriel-vasile/mimetype"
"github.com/karrick/godirwalk"
"github.com/pterodactyl/wings/config"
"github.com/pterodactyl/wings/system"
"io"
"io/ioutil"
"os"
"path"
"path/filepath"
"sort"
"strconv"
"strings"
"sync"
"time"
)
type Filesystem struct {
mu sync.RWMutex
lastLookupTime *usageLookupTime
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lookupInProgress *system.AtomicBool
diskUsed int64
diskCheckInterval time.Duration
// The maximum amount of disk space (in bytes) that this Filesystem instance can use.
diskLimit int64
// The root data directory path for this Filesystem instance.
root string
isTest bool
}
// Creates a new Filesystem instance for a given server.
func New(root string, size int64) *Filesystem {
return &Filesystem{
root: root,
diskLimit: size,
diskCheckInterval: time.Duration(config.Get().System.DiskCheckInterval),
lastLookupTime: &usageLookupTime{},
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lookupInProgress: system.NewAtomicBool(false),
}
}
// Returns the root path for the Filesystem instance.
func (fs *Filesystem) Path() string {
return fs.root
}
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// Returns a reader for a file instance.
func (fs *Filesystem) File(p string) (*os.File, os.FileInfo, error) {
cleaned, err := fs.SafePath(p)
if err != nil {
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return nil, nil, err
}
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st, err := os.Stat(cleaned)
if err != nil {
return nil, nil, err
}
if st.IsDir() {
return nil, nil, &Error{code: ErrCodeIsDirectory}
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}
f, err := os.Open(cleaned)
if err != nil {
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return nil, nil, err
}
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return f, st, nil
}
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// Reads a file on the system and returns it as a byte representation in a file
// reader. This is not the most memory efficient usage since it will be reading the
// entirety of the file into memory.
func (fs *Filesystem) Readfile(p string, w io.Writer) error {
file, _, err := fs.File(p)
if err != nil {
return err
}
defer file.Close()
_, err = bufio.NewReader(file).WriteTo(w)
return err
}
// Writes a file to the system. If the file does not already exist one will be created.
func (fs *Filesystem) Writefile(p string, r io.Reader) error {
cleaned, err := fs.SafePath(p)
if err != nil {
return err
}
var currentSize int64
// If the file does not exist on the system already go ahead and create the pathway
// to it and an empty file. We'll then write to it later on after this completes.
stat, err := os.Stat(cleaned)
if err != nil && !os.IsNotExist(err) {
return err
} else if err == nil {
if stat.IsDir() {
return &Error{code: ErrCodeIsDirectory}
}
currentSize = stat.Size()
}
br := bufio.NewReader(r)
// Check that the new size we're writing to the disk can fit. If there is currently
// a file we'll subtract that current file size from the size of the buffer to determine
// the amount of new data we're writing (or amount we're removing if smaller).
if err := fs.HasSpaceFor(int64(br.Size()) - currentSize); err != nil {
return err
}
// If we were unable to stat the location because it did not exist, go ahead and create
// it now. We do this after checking the disk space so that we do not just create empty
// directories at random.
if err != nil {
if err := os.MkdirAll(filepath.Dir(cleaned), 0755); err != nil {
return err
}
if err := fs.Chown(filepath.Dir(cleaned)); err != nil {
return err
}
}
o := &fileOpener{}
// This will either create the file if it does not already exist, or open and
// truncate the existing file.
file, err := o.open(cleaned, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
if err != nil {
return err
}
defer file.Close()
buf := make([]byte, 1024*4)
sz, err := io.CopyBuffer(file, r, buf)
// Adjust the disk usage to account for the old size and the new size of the file.
fs.addDisk(sz - currentSize)
// Finally, chown the file to ensure the permissions don't end up out-of-whack
// if we had just created it.
return fs.Chown(cleaned)
}
// Creates a new directory (name) at a specified path (p) for the server.
func (fs *Filesystem) CreateDirectory(name string, p string) error {
cleaned, err := fs.SafePath(path.Join(p, name))
if err != nil {
return err
}
return os.MkdirAll(cleaned, 0755)
}
// Moves (or renames) a file or directory.
func (fs *Filesystem) Rename(from string, to string) error {
cleanedFrom, err := fs.SafePath(from)
if err != nil {
return err
}
cleanedTo, err := fs.SafePath(to)
if err != nil {
return err
}
// If the target file or directory already exists the rename function will fail, so just
// bail out now.
if _, err := os.Stat(cleanedTo); err == nil {
return os.ErrExist
}
if cleanedTo == fs.Path() {
return errors.New("attempting to rename into an invalid directory space")
}
d := strings.TrimSuffix(cleanedTo, path.Base(cleanedTo))
// Ensure that the directory we're moving into exists correctly on the system. Only do this if
// we're not at the root directory level.
if d != fs.Path() {
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if mkerr := os.MkdirAll(d, 0755); mkerr != nil {
return errors.WithMessage(mkerr, "failed to create directory structure for file rename")
}
}
return os.Rename(cleanedFrom, cleanedTo)
}
// Recursively iterates over a file or directory and sets the permissions on all of the
// underlying files. Iterate over all of the files and directories. If it is a file just
// go ahead and perform the chown operation. Otherwise dig deeper into the directory until
// we've run out of directories to dig into.
func (fs *Filesystem) Chown(path string) error {
cleaned, err := fs.SafePath(path)
if err != nil {
return err
}
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if fs.isTest {
return nil
}
uid := config.Get().System.User.Uid
gid := config.Get().System.User.Gid
// Start by just chowning the initial path that we received.
if err := os.Chown(cleaned, uid, gid); err != nil {
return err
}
// If this is not a directory we can now return from the function, there is nothing
// left that we need to do.
if st, _ := os.Stat(cleaned); !st.IsDir() {
return nil
}
// If this was a directory, begin walking over its contents recursively and ensure that all
// of the subfiles and directories get their permissions updated as well.
return godirwalk.Walk(cleaned, &godirwalk.Options{
Unsorted: true,
Callback: func(p string, e *godirwalk.Dirent) error {
// Do not attempt to chmod a symlink. Go's os.Chown function will affect the symlink
// so if it points to a location outside the data directory the user would be able to
// (un)intentionally modify that files permissions.
if e.IsSymlink() {
if e.IsDir() {
return godirwalk.SkipThis
}
return nil
}
return os.Chown(p, uid, gid)
},
})
}
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func (fs *Filesystem) Chmod(path string, mode os.FileMode) error {
cleaned, err := fs.SafePath(path)
if err != nil {
return err
}
if fs.isTest {
return nil
}
if err := os.Chmod(cleaned, mode); err != nil {
return err
}
return nil
}
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// Begin looping up to 50 times to try and create a unique copy file name. This will take
// an input of "file.txt" and generate "file copy.txt". If that name is already taken, it will
// then try to write "file copy 2.txt" and so on, until reaching 50 loops. At that point we
// won't waste anymore time, just use the current timestamp and make that copy.
//
// Could probably make this more efficient by checking if there are any files matching the copy
// pattern, and trying to find the highest number and then incrementing it by one rather than
// looping endlessly.
func (fs *Filesystem) findCopySuffix(dir string, name string, extension string) (string, error) {
var i int
var suffix = " copy"
for i = 0; i < 51; i++ {
if i > 0 {
suffix = " copy " + strconv.Itoa(i)
}
n := name + suffix + extension
// If we stat the file and it does not exist that means we're good to create the copy. If it
// does exist, we'll just continue to the next loop and try again.
if _, err := fs.Stat(path.Join(dir, n)); err != nil {
if !errors.Is(err, os.ErrNotExist) {
return "", err
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}
break
}
if i == 50 {
suffix = "copy." + time.Now().Format(time.RFC3339)
}
}
return name + suffix + extension, nil
}
// Copies a given file to the same location and appends a suffix to the file to indicate that
// it has been copied.
func (fs *Filesystem) Copy(p string) error {
cleaned, err := fs.SafePath(p)
if err != nil {
return err
}
s, err := os.Stat(cleaned)
if err != nil {
return err
} else if s.IsDir() || !s.Mode().IsRegular() {
// If this is a directory or not a regular file, just throw a not-exist error
// since anything calling this function should understand what that means.
return os.ErrNotExist
}
// Check that copying this file wouldn't put the server over its limit.
if err := fs.HasSpaceFor(s.Size()); err != nil {
return err
}
base := filepath.Base(cleaned)
relative := strings.TrimSuffix(strings.TrimPrefix(cleaned, fs.Path()), base)
extension := filepath.Ext(base)
name := strings.TrimSuffix(base, extension)
// Ensure that ".tar" is also counted as apart of the file extension.
// There might be a better way to handle this for other double file extensions,
// but this is a good workaround for now.
if strings.HasSuffix(name, ".tar") {
extension = ".tar" + extension
name = strings.TrimSuffix(name, ".tar")
}
source, err := os.Open(cleaned)
if err != nil {
return err
}
defer source.Close()
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n, err := fs.findCopySuffix(relative, name, extension)
if err != nil {
return err
}
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return fs.Writefile(path.Join(relative, n), source)
}
// Deletes a file or folder from the system. Prevents the user from accidentally
// (or maliciously) removing their root server data directory.
func (fs *Filesystem) Delete(p string) error {
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wg := sync.WaitGroup{}
// This is one of the few (only?) places in the codebase where we're explicitly not using
// the SafePath functionality when working with user provided input. If we did, you would
// not be able to delete a file that is a symlink pointing to a location outside of the data
// directory.
//
// We also want to avoid resolving a symlink that points _within_ the data directory and thus
// deleting the actual source file for the symlink rather than the symlink itself. For these
// purposes just resolve the actual file path using filepath.Join() and confirm that the path
// exists within the data directory.
resolved := fs.unsafeFilePath(p)
if !fs.unsafeIsInDataDirectory(resolved) {
return NewBadPathResolution(p, resolved)
}
// Block any whoopsies.
if resolved == fs.Path() {
return errors.New("cannot delete root server directory")
}
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if st, err := os.Lstat(resolved); err != nil {
if !os.IsNotExist(err) {
fs.error(err).Warn("error while attempting to stat file before deletion")
}
} else {
if !st.IsDir() {
fs.addDisk(-st.Size())
} else {
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wg.Add(1)
go func(wg *sync.WaitGroup, st os.FileInfo, resolved string) {
defer wg.Done()
if s, err := fs.DirectorySize(resolved); err == nil {
fs.addDisk(-s)
}
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}(&wg, st, resolved)
}
}
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wg.Wait()
return os.RemoveAll(resolved)
}
type fileOpener struct {
busy uint
}
// Attempts to open a given file up to "attempts" number of times, using a backoff. If the file
// cannot be opened because of a "text file busy" error, we will attempt until the number of attempts
// has been exhaused, at which point we will abort with an error.
func (fo *fileOpener) open(path string, flags int, perm os.FileMode) (*os.File, error) {
for {
f, err := os.OpenFile(path, flags, perm)
// If there is an error because the text file is busy, go ahead and sleep for a few
// hundred milliseconds and then try again up to three times before just returning the
// error back to the caller.
//
// Based on code from: https://github.com/golang/go/issues/22220#issuecomment-336458122
if err != nil && fo.busy < 3 && strings.Contains(err.Error(), "text file busy") {
time.Sleep(100 * time.Millisecond << fo.busy)
fo.busy++
continue
}
return f, err
}
}
// Lists the contents of a given directory and returns stat information about each
// file and folder within it.
func (fs *Filesystem) ListDirectory(p string) ([]*Stat, error) {
cleaned, err := fs.SafePath(p)
if err != nil {
return nil, err
}
files, err := ioutil.ReadDir(cleaned)
if err != nil {
return nil, err
}
var wg sync.WaitGroup
// You must initialize the output of this directory as a non-nil value otherwise
// when it is marshaled into a JSON object you'll just get 'null' back, which will
// break the panel badly.
out := make([]*Stat, len(files))
// Iterate over all of the files and directories returned and perform an async process
// to get the mime-type for them all.
for i, file := range files {
wg.Add(1)
go func(idx int, f os.FileInfo) {
defer wg.Done()
var m *mimetype.MIME
var d = "inode/directory"
if !f.IsDir() {
cleanedp := filepath.Join(cleaned, f.Name())
if f.Mode()&os.ModeSymlink != 0 {
cleanedp, _ = fs.SafePath(filepath.Join(cleaned, f.Name()))
}
if cleanedp != "" {
m, _ = mimetype.DetectFile(filepath.Join(cleaned, f.Name()))
} else {
// Just pass this for an unknown type because the file could not safely be resolved within
// the server data path.
d = "application/octet-stream"
}
}
st := &Stat{
Info: f,
Mimetype: d,
}
if m != nil {
st.Mimetype = m.String()
}
out[idx] = st
}(i, file)
}
wg.Wait()
// Sort the output alphabetically to begin with since we've run the output
// through an asynchronous process and the order is gonna be very random.
sort.SliceStable(out, func(i, j int) bool {
if out[i].Info.Name() == out[j].Info.Name() || out[i].Info.Name() > out[j].Info.Name() {
return true
}
return false
})
// Then, sort it so that directories are listed first in the output. Everything
// will continue to be alphabetized at this point.
sort.SliceStable(out, func(i, j int) bool {
return out[i].Info.IsDir()
})
return out, nil
}