135 lines
3.6 KiB
Go
135 lines
3.6 KiB
Go
// Copyright 2020 The gVisor Authors.
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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 fsbridge
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import (
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"io"
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"gvisor.dev/gvisor/pkg/abi/linux"
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"gvisor.dev/gvisor/pkg/context"
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"gvisor.dev/gvisor/pkg/fspath"
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"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
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"gvisor.dev/gvisor/pkg/sentry/memmap"
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"gvisor.dev/gvisor/pkg/sentry/vfs"
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"gvisor.dev/gvisor/pkg/usermem"
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)
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// fsFile implements File interface over vfs.FileDescription.
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//
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// +stateify savable
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type vfsFile struct {
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file *vfs.FileDescription
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}
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var _ File = (*vfsFile)(nil)
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// NewVFSFile creates a new File over fs.File.
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func NewVFSFile(file *vfs.FileDescription) File {
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return &vfsFile{file: file}
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}
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// PathnameWithDeleted implements File.
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func (f *vfsFile) PathnameWithDeleted(ctx context.Context) string {
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root := vfs.RootFromContext(ctx)
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defer root.DecRef()
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vfsObj := f.file.VirtualDentry().Mount().Filesystem().VirtualFilesystem()
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name, _ := vfsObj.PathnameWithDeleted(ctx, root, f.file.VirtualDentry())
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return name
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}
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// ReadFull implements File.
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func (f *vfsFile) ReadFull(ctx context.Context, dst usermem.IOSequence, offset int64) (int64, error) {
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var total int64
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for dst.NumBytes() > 0 {
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n, err := f.file.PRead(ctx, dst, offset+total, vfs.ReadOptions{})
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total += n
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if err == io.EOF && total != 0 {
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return total, io.ErrUnexpectedEOF
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} else if err != nil {
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return total, err
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}
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dst = dst.DropFirst64(n)
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}
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return total, nil
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}
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// ConfigureMMap implements File.
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func (f *vfsFile) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpts) error {
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return f.file.ConfigureMMap(ctx, opts)
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}
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// Type implements File.
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func (f *vfsFile) Type(ctx context.Context) (linux.FileMode, error) {
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stat, err := f.file.Stat(ctx, vfs.StatOptions{})
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if err != nil {
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return 0, err
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}
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return linux.FileMode(stat.Mode).FileType(), nil
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}
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// IncRef implements File.
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func (f *vfsFile) IncRef() {
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f.file.IncRef()
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}
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// DecRef implements File.
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func (f *vfsFile) DecRef() {
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f.file.DecRef()
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}
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// fsLookup implements Lookup interface using fs.File.
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//
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// +stateify savable
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type vfsLookup struct {
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mntns *vfs.MountNamespace
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root vfs.VirtualDentry
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workingDir vfs.VirtualDentry
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}
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var _ Lookup = (*vfsLookup)(nil)
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// NewVFSLookup creates a new Lookup using VFS2.
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func NewVFSLookup(mntns *vfs.MountNamespace, root, workingDir vfs.VirtualDentry) Lookup {
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return &vfsLookup{
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mntns: mntns,
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root: root,
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workingDir: workingDir,
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}
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}
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// OpenPath implements Lookup.
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//
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// remainingTraversals is not configurable in VFS2, all callers are using the
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// default anyways.
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//
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// TODO(gvisor.dev/issue/1623): Check mount has read and exec permission.
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func (l *vfsLookup) OpenPath(ctx context.Context, path string, opts vfs.OpenOptions, _ *uint, resolveFinal bool) (File, error) {
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vfsObj := l.mntns.Root().Mount().Filesystem().VirtualFilesystem()
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creds := auth.CredentialsFromContext(ctx)
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pop := &vfs.PathOperation{
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Root: l.root,
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Start: l.root,
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Path: fspath.Parse(path),
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FollowFinalSymlink: resolveFinal,
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}
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fd, err := vfsObj.OpenAt(ctx, creds, pop, &opts)
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if err != nil {
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return nil, err
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}
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return &vfsFile{file: fd}, nil
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}
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