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// Copyright 2019 The gVisor Authors.
//
// 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 kernfs
import (
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/sentry/vfs"
"gvisor.dev/gvisor/pkg/syserror"
)
// StaticSymlink provides an Inode implementation for symlinks that point to
// a immutable target.
//
// +stateify savable
type StaticSymlink struct {
InodeAttrs
InodeNoopRefCount
InodeSymlink
InodeNoStatFS
target string
}
var _ Inode = (*StaticSymlink)(nil)
// NewStaticSymlink creates a new symlink file pointing to 'target'.
func NewStaticSymlink(creds *auth.Credentials, devMajor, devMinor uint32, ino uint64, target string) *Dentry {
inode := &StaticSymlink{}
inode.Init(creds, devMajor, devMinor, ino, target)
d := &Dentry{}
d.Init(inode)
return d
}
// Init initializes the instance.
func (s *StaticSymlink) Init(creds *auth.Credentials, devMajor uint32, devMinor uint32, ino uint64, target string) {
s.target = target
s.InodeAttrs.Init(creds, devMajor, devMinor, ino, linux.ModeSymlink|0777)
}
// Readlink implements Inode.Readlink.
func (s *StaticSymlink) Readlink(_ context.Context, _ *vfs.Mount) (string, error) {
return s.target, nil
}
// Getlink implements Inode.Getlink.
func (s *StaticSymlink) Getlink(context.Context, *vfs.Mount) (vfs.VirtualDentry, string, error) {
return vfs.VirtualDentry{}, s.target, nil
}
// SetStat implements Inode.SetStat not allowing inode attributes to be changed.
func (*StaticSymlink) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials, vfs.SetStatOptions) error {
return syserror.EPERM
}
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