128 lines
4.4 KiB
Go
128 lines
4.4 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 dev
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import (
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"gvisor.googlesource.com/gvisor/pkg/abi/linux"
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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/fs/fsutil"
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"gvisor.googlesource.com/gvisor/pkg/sentry/memmap"
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"gvisor.googlesource.com/gvisor/pkg/sentry/mm"
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"gvisor.googlesource.com/gvisor/pkg/sentry/pgalloc"
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"gvisor.googlesource.com/gvisor/pkg/waiter"
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)
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// +stateify savable
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type nullDevice struct {
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fsutil.InodeGenericChecker `state:"nosave"`
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fsutil.InodeNoExtendedAttributes `state:"nosave"`
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fsutil.InodeNoopRelease `state:"nosave"`
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fsutil.InodeNoopTruncate `state:"nosave"`
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fsutil.InodeNoopWriteOut `state:"nosave"`
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fsutil.InodeNotDirectory `state:"nosave"`
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fsutil.InodeNotMappable `state:"nosave"`
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fsutil.InodeNotSocket `state:"nosave"`
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fsutil.InodeNotSymlink `state:"nosave"`
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fsutil.InodeVirtual `state:"nosave"`
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fsutil.InodeSimpleAttributes
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}
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var _ fs.InodeOperations = (*nullDevice)(nil)
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func newNullDevice(ctx context.Context, owner fs.FileOwner, mode linux.FileMode) *nullDevice {
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n := &nullDevice{
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InodeSimpleAttributes: fsutil.NewInodeSimpleAttributes(ctx, owner, fs.FilePermsFromMode(mode), linux.TMPFS_MAGIC),
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}
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return n
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}
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// GetFile implements fs.FileOperations.GetFile.
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func (n *nullDevice) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags) (*fs.File, error) {
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flags.Pread = true
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flags.Pwrite = true
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return fs.NewFile(ctx, dirent, flags, &nullFileOperations{}), nil
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}
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// +stateify savable
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type nullFileOperations struct {
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waiter.AlwaysReady `state:"nosave"`
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fsutil.FileGenericSeek `state:"nosave"`
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fsutil.FileNoIoctl `state:"nosave"`
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fsutil.FileNoMMap `state:"nosave"`
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fsutil.FileNoopFlush `state:"nosave"`
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fsutil.FileNoopFsync `state:"nosave"`
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fsutil.FileNoopRead `state:"nosave"`
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fsutil.FileNoopWrite `state:"nosave"`
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fsutil.FileNoopRelease `state:"nosave"`
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fsutil.FileNotDirReaddir `state:"nosave"`
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fsutil.FileUseInodeUnstableAttr `state:"nosave"`
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}
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var _ fs.FileOperations = (*nullFileOperations)(nil)
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// +stateify savable
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type zeroDevice struct {
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nullDevice
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}
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var _ fs.InodeOperations = (*zeroDevice)(nil)
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func newZeroDevice(ctx context.Context, owner fs.FileOwner, mode linux.FileMode) *zeroDevice {
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zd := &zeroDevice{
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nullDevice: nullDevice{
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InodeSimpleAttributes: fsutil.NewInodeSimpleAttributes(ctx, owner, fs.FilePermsFromMode(mode), linux.TMPFS_MAGIC),
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},
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}
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return zd
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}
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// GetFile implements fs.FileOperations.GetFile.
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func (zd *zeroDevice) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags) (*fs.File, error) {
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flags.Pread = true
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flags.Pwrite = true
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return fs.NewFile(ctx, dirent, flags, &zeroFileOperations{}), nil
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}
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// +stateify savable
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type zeroFileOperations struct {
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waiter.AlwaysReady `state:"nosave"`
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fsutil.FileGenericSeek `state:"nosave"`
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fsutil.FileNoopFlush `state:"nosave"`
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fsutil.FileNoopFsync `state:"nosave"`
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fsutil.FileNoopRelease `state:"nosave"`
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fsutil.FileNoopWrite `state:"nosave"`
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fsutil.FileNotDirReaddir `state:"nosave"`
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fsutil.FileNoIoctl `state:"nosave"`
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fsutil.FileUseInodeUnstableAttr `state:"nosave"`
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readZeros `state:"nosave"`
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}
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var _ fs.FileOperations = (*zeroFileOperations)(nil)
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// ConfigureMMap implements fs.FileOperations.ConfigureMMap.
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func (*zeroFileOperations) ConfigureMMap(ctx context.Context, file *fs.File, opts *memmap.MMapOpts) error {
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m, err := mm.NewSharedAnonMappable(opts.Length, pgalloc.MemoryFileProviderFromContext(ctx))
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if err != nil {
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return err
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}
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opts.MappingIdentity = m
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opts.Mappable = m
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return nil
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}
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