105 lines
3.5 KiB
Go
105 lines
3.5 KiB
Go
// Copyright 2018 Google LLC
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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 ramfs
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import (
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"gvisor.googlesource.com/gvisor/pkg/abi/linux"
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"gvisor.googlesource.com/gvisor/pkg/sentry/context"
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"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
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"gvisor.googlesource.com/gvisor/pkg/sentry/fs/fsutil"
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"gvisor.googlesource.com/gvisor/pkg/waiter"
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)
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// Symlink represents a symlink.
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//
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// +stateify savable
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type Symlink struct {
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fsutil.InodeGenericChecker `state:"nosave"`
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fsutil.InodeNoopRelease `state:"nosave"`
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fsutil.InodeNoopWriteOut `state:"nosave"`
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fsutil.InodeNotDirectory `state:"nosave"`
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fsutil.InodeNotMappable `state:"nosave"`
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fsutil.InodeNotTruncatable `state:"nosave"`
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fsutil.InodeNotSocket `state:"nosave"`
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fsutil.InodeVirtual `state:"nosave"`
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fsutil.InodeSimpleAttributes
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fsutil.InodeSimpleExtendedAttributes
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// Target is the symlink target.
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Target string
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}
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var _ fs.InodeOperations = (*Symlink)(nil)
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// NewSymlink returns a new Symlink.
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func NewSymlink(ctx context.Context, owner fs.FileOwner, target string) *Symlink {
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// A symlink is assumed to always have permissions 0777.
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return &Symlink{
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InodeSimpleAttributes: fsutil.NewInodeSimpleAttributes(ctx, owner, fs.FilePermsFromMode(0777), linux.RAMFS_MAGIC),
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Target: target,
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}
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}
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// UnstableAttr returns all attributes of this ramfs symlink.
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func (s *Symlink) UnstableAttr(ctx context.Context, inode *fs.Inode) (fs.UnstableAttr, error) {
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uattr, err := s.InodeSimpleAttributes.UnstableAttr(ctx, inode)
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if err != nil {
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return fs.UnstableAttr{}, err
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}
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uattr.Size = int64(len(s.Target))
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uattr.Usage = uattr.Size
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return uattr, nil
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}
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// SetPermissions on a symlink is always rejected.
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func (s *Symlink) SetPermissions(context.Context, *fs.Inode, fs.FilePermissions) bool {
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return false
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}
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// Readlink reads the symlink value.
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func (s *Symlink) Readlink(ctx context.Context, _ *fs.Inode) (string, error) {
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s.NotifyAccess(ctx)
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return s.Target, nil
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}
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// Getlink returns ErrResolveViaReadlink, falling back to walking to the result
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// of Readlink().
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func (*Symlink) Getlink(context.Context, *fs.Inode) (*fs.Dirent, error) {
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return nil, fs.ErrResolveViaReadlink
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}
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// GetFile implements fs.FileOperations.GetFile.
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func (s *Symlink) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags) (*fs.File, error) {
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return fs.NewFile(ctx, dirent, flags, &symlinkFileOperations{}), nil
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}
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// +stateify savable
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type symlinkFileOperations struct {
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waiter.AlwaysReady `state:"nosave"`
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fsutil.FileNoIoctl `state:"nosave"`
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fsutil.FileNoMMap `state:"nosave"`
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fsutil.FileNoopFlush `state:"nosave"`
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fsutil.FileNoopFsync `state:"nosave"`
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fsutil.FileNoopRelease `state:"nosave"`
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fsutil.FileNoRead `state:"nosave"`
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fsutil.FileNoSeek `state:"nosave"`
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fsutil.FileNotDirReaddir `state:"nosave"`
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fsutil.FileNoWrite `state:"nosave"`
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fsutil.FileUseInodeUnstableAttr `state:"nosave"`
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}
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var _ fs.FileOperations = (*symlinkFileOperations)(nil)
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