119 lines
2.6 KiB
Go
119 lines
2.6 KiB
Go
// Copyright 2015 Google Inc. 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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//
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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 errorfs
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import (
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"fmt"
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"os"
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"reflect"
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"sync"
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"syscall"
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"golang.org/x/net/context"
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"github.com/jacobsa/fuse/fuseops"
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"github.com/jacobsa/fuse/fuseutil"
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)
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const FooContents = "xxxx"
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const fooInodeID = fuseops.RootInodeID + 1
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// A file system whose sole contents are a file named "foo" containing the
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// string defined by FooContents.
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//
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// The file system can be configured to returned canned errors for particular
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// operations using the method SetError.
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type FS interface {
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fuseutil.FileSystem
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// Cause the file system to return the supplied error for all future
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// operations matching the supplied type.
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SetError(t reflect.Type, err syscall.Errno)
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}
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func New() (fs FS, err error) {
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fs = &errorFS{
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errors: make(map[reflect.Type]syscall.Errno),
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}
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return
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}
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type errorFS struct {
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fuseutil.NotImplementedFileSystem
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mu sync.Mutex
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// GUARDED_BY(mu)
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errors map[reflect.Type]syscall.Errno
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}
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// LOCKS_EXCLUDED(fs.mu)
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func (fs *errorFS) SetError(t reflect.Type, err syscall.Errno) {
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fs.mu.Lock()
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defer fs.mu.Unlock()
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fs.errors[t] = err
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}
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// LOCKS_EXCLUDED(fs.mu)
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func (fs *errorFS) transformError(op interface{}, err *error) bool {
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fs.mu.Lock()
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defer fs.mu.Unlock()
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cannedErr, ok := fs.errors[reflect.TypeOf(op)]
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if ok {
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*err = cannedErr
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return true
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}
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return false
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}
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////////////////////////////////////////////////////////////////////////
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// File system methods
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////////////////////////////////////////////////////////////////////////
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// LOCKS_EXCLUDED(fs.mu)
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func (fs *errorFS) GetInodeAttributes(
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ctx context.Context,
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op *fuseops.GetInodeAttributesOp) (err error) {
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if fs.transformError(op, &err) {
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return
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}
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// Figure out which inode the request is for.
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switch {
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case op.Inode == fuseops.RootInodeID:
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op.Attributes = fuseops.InodeAttributes{
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Mode: os.ModeDir | 0777,
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}
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case op.Inode == fooInodeID:
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op.Attributes = fuseops.InodeAttributes{
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Nlink: 1,
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Size: uint64(len(FooContents)),
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Mode: 0444,
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}
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default:
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err = fmt.Errorf("Unknown inode: %d", op.Inode)
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return
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}
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return
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}
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