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// Copyright 2018 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package ramfs
import (
"sync"
"gvisor.googlesource.com/gvisor/pkg/sentry/context"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
)
// Symlink represents a symlink.
type Symlink struct {
Entry
mu sync.Mutex `state:"nosave"`
// Target is the symlink target.
Target string
}
// InitSymlink initializes a symlink, pointing to the given target.
// A symlink is assumed to always have permissions 0777.
func (s *Symlink) InitSymlink(ctx context.Context, owner fs.FileOwner, target string) {
s.InitEntry(ctx, owner, fs.FilePermsFromMode(0777))
s.Target = target
}
// UnstableAttr returns all attributes of this ramfs symlink.
func (s *Symlink) UnstableAttr(ctx context.Context, inode *fs.Inode) (fs.UnstableAttr, error) {
uattr, _ := s.Entry.UnstableAttr(ctx, inode)
uattr.Size = int64(len(s.Target))
uattr.Usage = uattr.Size
return uattr, nil
}
// Check implements InodeOperations.Check.
func (s *Symlink) Check(ctx context.Context, inode *fs.Inode, p fs.PermMask) bool {
return fs.ContextCanAccessFile(ctx, inode, p)
}
// SetPermissions on a symlink is always rejected.
func (s *Symlink) SetPermissions(context.Context, *fs.Inode, fs.FilePermissions) bool {
return false
}
// Readlink reads the symlink value.
func (s *Symlink) Readlink(ctx context.Context, _ *fs.Inode) (string, error) {
s.mu.Lock()
defer s.mu.Unlock()
s.Entry.NotifyAccess(ctx)
return s.Target, nil
}
// Getlink returns ErrResolveViaReadlink, falling back to walking to the result
// of Readlink().
func (*Symlink) Getlink(context.Context, *fs.Inode) (*fs.Dirent, error) {
return nil, fs.ErrResolveViaReadlink
}
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