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file.go
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file.go
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package file
import (
"context"
"encoding/json"
"errors"
"fmt"
"io"
"os"
"path/filepath"
"sort"
"strings"
"sync"
"github.com/hashicorp/errwrap"
log "github.com/hashicorp/go-hclog"
"github.com/hashicorp/vault/helper/consts"
"github.com/hashicorp/vault/helper/jsonutil"
"github.com/hashicorp/vault/physical"
)
// Verify FileBackend satisfies the correct interfaces
var _ physical.Backend = (*FileBackend)(nil)
var _ physical.Transactional = (*TransactionalFileBackend)(nil)
var _ physical.PseudoTransactional = (*FileBackend)(nil)
// FileBackend is a physical backend that stores data on disk
// at a given file path. It can be used for durable single server
// situations, or to develop locally where durability is not critical.
//
// WARNING: the file backend implementation is currently extremely unsafe
// and non-performant. It is meant mostly for local testing and development.
// It can be improved in the future.
type FileBackend struct {
sync.RWMutex
path string
logger log.Logger
permitPool *physical.PermitPool
}
type TransactionalFileBackend struct {
FileBackend
}
type fileEntry struct {
Value []byte
}
// NewFileBackend constructs a FileBackend using the given directory
func NewFileBackend(conf map[string]string, logger log.Logger) (physical.Backend, error) {
path, ok := conf["path"]
if !ok {
return nil, fmt.Errorf("'path' must be set")
}
return &FileBackend{
path: path,
logger: logger,
permitPool: physical.NewPermitPool(physical.DefaultParallelOperations),
}, nil
}
func NewTransactionalFileBackend(conf map[string]string, logger log.Logger) (physical.Backend, error) {
path, ok := conf["path"]
if !ok {
return nil, fmt.Errorf("'path' must be set")
}
// Create a pool of size 1 so only one operation runs at a time
return &TransactionalFileBackend{
FileBackend: FileBackend{
path: path,
logger: logger,
permitPool: physical.NewPermitPool(1),
},
}, nil
}
func (b *FileBackend) Delete(ctx context.Context, path string) error {
b.permitPool.Acquire()
defer b.permitPool.Release()
b.Lock()
defer b.Unlock()
return b.DeleteInternal(ctx, path)
}
func (b *FileBackend) DeleteInternal(ctx context.Context, path string) error {
if path == "" {
return nil
}
if err := b.validatePath(path); err != nil {
return err
}
basePath, key := b.expandPath(path)
fullPath := filepath.Join(basePath, key)
select {
case <-ctx.Done():
return ctx.Err()
default:
}
err := os.Remove(fullPath)
if err != nil && !os.IsNotExist(err) {
return errwrap.Wrapf(fmt.Sprintf("failed to remove %q: {{err}}", fullPath), err)
}
err = b.cleanupLogicalPath(path)
return err
}
// cleanupLogicalPath is used to remove all empty nodes, beginning with deepest
// one, aborting on first non-empty one, up to top-level node.
func (b *FileBackend) cleanupLogicalPath(path string) error {
nodes := strings.Split(path, fmt.Sprintf("%c", os.PathSeparator))
for i := len(nodes) - 1; i > 0; i-- {
fullPath := filepath.Join(b.path, filepath.Join(nodes[:i]...))
dir, err := os.Open(fullPath)
if err != nil {
if dir != nil {
dir.Close()
}
if os.IsNotExist(err) {
return nil
} else {
return err
}
}
list, err := dir.Readdir(1)
dir.Close()
if err != nil && err != io.EOF {
return err
}
// If we have no entries, it's an empty directory; remove it
if err == io.EOF || list == nil || len(list) == 0 {
err = os.Remove(fullPath)
if err != nil {
return err
}
}
}
return nil
}
func (b *FileBackend) Get(ctx context.Context, k string) (*physical.Entry, error) {
b.permitPool.Acquire()
defer b.permitPool.Release()
b.RLock()
defer b.RUnlock()
return b.GetInternal(ctx, k)
}
func (b *FileBackend) GetInternal(ctx context.Context, k string) (*physical.Entry, error) {
if err := b.validatePath(k); err != nil {
return nil, err
}
path, key := b.expandPath(k)
path = filepath.Join(path, key)
// If we stat it and it exists but is size zero, it may be left from some
// previous FS error like out-of-space. No Vault entry will ever be zero
// length, so simply remove it and return nil.
fi, err := os.Stat(path)
if err == nil {
if fi.Size() == 0 {
// Best effort, ignore errors
os.Remove(path)
return nil, nil
}
}
f, err := os.Open(path)
if f != nil {
defer f.Close()
}
if err != nil {
if os.IsNotExist(err) {
return nil, nil
}
return nil, err
}
var entry fileEntry
if err := jsonutil.DecodeJSONFromReader(f, &entry); err != nil {
return nil, err
}
select {
case <-ctx.Done():
return nil, ctx.Err()
default:
}
return &physical.Entry{
Key: k,
Value: entry.Value,
}, nil
}
func (b *FileBackend) Put(ctx context.Context, entry *physical.Entry) error {
b.permitPool.Acquire()
defer b.permitPool.Release()
b.Lock()
defer b.Unlock()
return b.PutInternal(ctx, entry)
}
func (b *FileBackend) PutInternal(ctx context.Context, entry *physical.Entry) error {
if err := b.validatePath(entry.Key); err != nil {
return err
}
path, key := b.expandPath(entry.Key)
// Make the parent tree
if err := os.MkdirAll(path, 0700); err != nil {
return err
}
// JSON encode the entry and write it
fullPath := filepath.Join(path, key)
f, err := os.OpenFile(
fullPath,
os.O_CREATE|os.O_TRUNC|os.O_WRONLY,
0600)
if err != nil {
if f != nil {
f.Close()
}
return err
}
if f == nil {
return errors.New("could not successfully get a file handle")
}
select {
case <-ctx.Done():
return ctx.Err()
default:
}
enc := json.NewEncoder(f)
encErr := enc.Encode(&fileEntry{
Value: entry.Value,
})
f.Close()
if encErr == nil {
return nil
}
// Everything below is best-effort and will result in encErr being returned
// See if we ended up with a zero-byte file and if so delete it, might be a
// case of disk being full but the file info is in metadata that is
// reserved.
fi, err := os.Stat(fullPath)
if err != nil {
return encErr
}
if fi == nil {
return encErr
}
if fi.Size() == 0 {
os.Remove(fullPath)
}
return encErr
}
func (b *FileBackend) List(ctx context.Context, prefix string) ([]string, error) {
b.permitPool.Acquire()
defer b.permitPool.Release()
b.RLock()
defer b.RUnlock()
return b.ListInternal(ctx, prefix)
}
func (b *FileBackend) ListInternal(ctx context.Context, prefix string) ([]string, error) {
if err := b.validatePath(prefix); err != nil {
return nil, err
}
path := b.path
if prefix != "" {
path = filepath.Join(path, prefix)
}
// Read the directory contents
f, err := os.Open(path)
if f != nil {
defer f.Close()
}
if err != nil {
if os.IsNotExist(err) {
return nil, nil
}
return nil, err
}
names, err := f.Readdirnames(-1)
if err != nil {
return nil, err
}
for i, name := range names {
fi, err := os.Stat(filepath.Join(path, name))
if err != nil {
return nil, err
}
if fi.IsDir() {
names[i] = name + "/"
} else {
if name[0] == '_' {
names[i] = name[1:]
}
}
}
select {
case <-ctx.Done():
return nil, ctx.Err()
default:
}
if len(names) > 0 {
sort.Strings(names)
}
return names, nil
}
func (b *FileBackend) expandPath(k string) (string, string) {
path := filepath.Join(b.path, k)
key := filepath.Base(path)
path = filepath.Dir(path)
return path, "_" + key
}
func (b *FileBackend) validatePath(path string) error {
switch {
case strings.Contains(path, ".."):
return consts.ErrPathContainsParentReferences
}
return nil
}
func (b *TransactionalFileBackend) Transaction(ctx context.Context, txns []*physical.TxnEntry) error {
b.permitPool.Acquire()
defer b.permitPool.Release()
b.Lock()
defer b.Unlock()
return physical.GenericTransactionHandler(ctx, b, txns)
}