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// Copyright 2020 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 fsbridge
import (
"io"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/fspath"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/sentry/memmap"
"gvisor.dev/gvisor/pkg/sentry/vfs"
"gvisor.dev/gvisor/pkg/usermem"
)
// VFSFile implements File interface over vfs.FileDescription.
//
// +stateify savable
type VFSFile struct {
file *vfs.FileDescription
}
var _ File = (*VFSFile)(nil)
// NewVFSFile creates a new File over fs.File.
func NewVFSFile(file *vfs.FileDescription) File {
return &VFSFile{file: file}
}
// PathnameWithDeleted implements File.
func (f *VFSFile) PathnameWithDeleted(ctx context.Context) string {
root := vfs.RootFromContext(ctx)
defer root.DecRef(ctx)
vfsObj := f.file.VirtualDentry().Mount().Filesystem().VirtualFilesystem()
name, _ := vfsObj.PathnameWithDeleted(ctx, root, f.file.VirtualDentry())
return name
}
// ReadFull implements File.
func (f *VFSFile) ReadFull(ctx context.Context, dst usermem.IOSequence, offset int64) (int64, error) {
var total int64
for dst.NumBytes() > 0 {
n, err := f.file.PRead(ctx, dst, offset+total, vfs.ReadOptions{})
total += n
if err == io.EOF && total != 0 {
return total, io.ErrUnexpectedEOF
} else if err != nil {
return total, err
}
dst = dst.DropFirst64(n)
}
return total, nil
}
// ConfigureMMap implements File.
func (f *VFSFile) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpts) error {
return f.file.ConfigureMMap(ctx, opts)
}
// Type implements File.
func (f *VFSFile) Type(ctx context.Context) (linux.FileMode, error) {
stat, err := f.file.Stat(ctx, vfs.StatOptions{})
if err != nil {
return 0, err
}
return linux.FileMode(stat.Mode).FileType(), nil
}
// IncRef implements File.
func (f *VFSFile) IncRef() {
f.file.IncRef()
}
// DecRef implements File.
func (f *VFSFile) DecRef(ctx context.Context) {
f.file.DecRef(ctx)
}
// FileDescription returns the FileDescription represented by f. It does not
// take an additional reference on the returned FileDescription.
func (f *VFSFile) FileDescription() *vfs.FileDescription {
return f.file
}
// fsLookup implements Lookup interface using fs.File.
//
// +stateify savable
type vfsLookup struct {
mntns *vfs.MountNamespace
root vfs.VirtualDentry
workingDir vfs.VirtualDentry
}
var _ Lookup = (*vfsLookup)(nil)
// NewVFSLookup creates a new Lookup using VFS2.
func NewVFSLookup(mntns *vfs.MountNamespace, root, workingDir vfs.VirtualDentry) Lookup {
return &vfsLookup{
mntns: mntns,
root: root,
workingDir: workingDir,
}
}
// OpenPath implements Lookup.
//
// remainingTraversals is not configurable in VFS2, all callers are using the
// default anyways.
func (l *vfsLookup) OpenPath(ctx context.Context, pathname string, opts vfs.OpenOptions, _ *uint, resolveFinal bool) (File, error) {
vfsObj := l.root.Mount().Filesystem().VirtualFilesystem()
creds := auth.CredentialsFromContext(ctx)
path := fspath.Parse(pathname)
pop := &vfs.PathOperation{
Root: l.root,
Start: l.workingDir,
Path: path,
FollowFinalSymlink: resolveFinal,
}
if path.Absolute {
pop.Start = l.root
}
fd, err := vfsObj.OpenAt(ctx, creds, pop, &opts)
if err != nil {
return nil, err
}
return &VFSFile{file: fd}, nil
}
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