129 lines
4.3 KiB
Go
129 lines
4.3 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 fsutil
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import (
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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/memmap"
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"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
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"gvisor.googlesource.com/gvisor/pkg/syserror"
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"gvisor.googlesource.com/gvisor/pkg/waiter"
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)
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// Handle implements FileOperations.
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//
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// FIXME: Remove Handle entirely in favor of individual fs.File
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// implementations using simple generic utilities.
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//
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// +stateify savable
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type Handle struct {
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NoopRelease `state:"nosave"`
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NoIoctl `state:"nosave"`
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HandleOperations fs.HandleOperations
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// dirCursor is the directory cursor.
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dirCursor string
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}
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// NewHandle returns a File backed by the Dirent and FileFlags.
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func NewHandle(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags, hops fs.HandleOperations) *fs.File {
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if !fs.IsPipe(dirent.Inode.StableAttr) && !fs.IsSocket(dirent.Inode.StableAttr) {
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// Allow reading/writing at an arbitrary offset for non-pipes
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// and non-sockets.
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flags.Pread = true
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flags.Pwrite = true
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}
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return fs.NewFile(ctx, dirent, flags, &Handle{HandleOperations: hops})
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}
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// Readiness implements waiter.Waitable.Readiness.
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func (h *Handle) Readiness(mask waiter.EventMask) waiter.EventMask {
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return h.HandleOperations.Readiness(mask)
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}
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// EventRegister implements waiter.Waitable.EventRegister.
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func (h *Handle) EventRegister(e *waiter.Entry, mask waiter.EventMask) {
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h.HandleOperations.EventRegister(e, mask)
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}
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// EventUnregister implements waiter.Waitable.EventUnregister.
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func (h *Handle) EventUnregister(e *waiter.Entry) {
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h.HandleOperations.EventUnregister(e)
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}
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// Readdir implements FileOperations.Readdir.
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func (h *Handle) Readdir(ctx context.Context, file *fs.File, serializer fs.DentrySerializer) (int64, error) {
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root := fs.RootFromContext(ctx)
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defer root.DecRef()
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dirCtx := &fs.DirCtx{
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Serializer: serializer,
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DirCursor: &h.dirCursor,
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}
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n, err := fs.DirentReaddir(ctx, file.Dirent, h, root, dirCtx, file.Offset())
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return n, err
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}
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// Seek implements FileOperations.Seek.
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func (h *Handle) Seek(ctx context.Context, file *fs.File, whence fs.SeekWhence, offset int64) (int64, error) {
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return SeekWithDirCursor(ctx, file, whence, offset, &h.dirCursor)
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}
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// IterateDir implements DirIterator.IterateDir.
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func (h *Handle) IterateDir(ctx context.Context, dirCtx *fs.DirCtx, offset int) (int, error) {
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return h.HandleOperations.DeprecatedReaddir(ctx, dirCtx, offset)
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}
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// Read implements FileOperations.Read.
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func (h *Handle) Read(ctx context.Context, file *fs.File, dst usermem.IOSequence, offset int64) (int64, error) {
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return h.HandleOperations.DeprecatedPreadv(ctx, dst, offset)
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}
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// Write implements FileOperations.Write.
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func (h *Handle) Write(ctx context.Context, file *fs.File, src usermem.IOSequence, offset int64) (int64, error) {
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return h.HandleOperations.DeprecatedPwritev(ctx, src, offset)
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}
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// Fsync implements FileOperations.Fsync.
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func (h *Handle) Fsync(ctx context.Context, file *fs.File, start int64, end int64, syncType fs.SyncType) error {
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switch syncType {
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case fs.SyncAll, fs.SyncData:
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// Write out metadata.
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if err := file.Dirent.Inode.WriteOut(ctx); err != nil {
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return err
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}
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fallthrough
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case fs.SyncBackingStorage:
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// Use DeprecatedFsync to sync disks.
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return h.HandleOperations.DeprecatedFsync()
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}
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panic("invalid sync type")
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}
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// Flush implements FileOperations.Flush.
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func (h *Handle) Flush(context.Context, *fs.File) error {
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return h.HandleOperations.DeprecatedFlush()
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}
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// ConfigureMMap implements FileOperations.ConfigureMMap.
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func (h *Handle) ConfigureMMap(ctx context.Context, file *fs.File, opts *memmap.MMapOpts) error {
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mappable := file.Dirent.Inode.Mappable()
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if mappable == nil {
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return syserror.ENODEV
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}
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return GenericConfigureMMap(file, mappable, opts)
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}
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