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// Copyright 2018 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 dev
import (
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/sentry/context"
"gvisor.dev/gvisor/pkg/sentry/fs"
"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
"gvisor.dev/gvisor/pkg/sentry/memmap"
"gvisor.dev/gvisor/pkg/sentry/mm"
"gvisor.dev/gvisor/pkg/sentry/pgalloc"
"gvisor.dev/gvisor/pkg/waiter"
)
// +stateify savable
type nullDevice struct {
fsutil.InodeGenericChecker `state:"nosave"`
fsutil.InodeNoExtendedAttributes `state:"nosave"`
fsutil.InodeNoopAllocate `state:"nosave"`
fsutil.InodeNoopRelease `state:"nosave"`
fsutil.InodeNoopTruncate `state:"nosave"`
fsutil.InodeNoopWriteOut `state:"nosave"`
fsutil.InodeNotDirectory `state:"nosave"`
fsutil.InodeNotMappable `state:"nosave"`
fsutil.InodeNotSocket `state:"nosave"`
fsutil.InodeNotSymlink `state:"nosave"`
fsutil.InodeVirtual `state:"nosave"`
fsutil.InodeSimpleAttributes
}
var _ fs.InodeOperations = (*nullDevice)(nil)
func newNullDevice(ctx context.Context, owner fs.FileOwner, mode linux.FileMode) *nullDevice {
n := &nullDevice{
InodeSimpleAttributes: fsutil.NewInodeSimpleAttributes(ctx, owner, fs.FilePermsFromMode(mode), linux.TMPFS_MAGIC),
}
return n
}
// GetFile implements fs.FileOperations.GetFile.
func (n *nullDevice) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags) (*fs.File, error) {
flags.Pread = true
flags.Pwrite = true
return fs.NewFile(ctx, dirent, flags, &nullFileOperations{}), nil
}
// +stateify savable
type nullFileOperations struct {
fsutil.FileGenericSeek `state:"nosave"`
fsutil.FileNoIoctl `state:"nosave"`
fsutil.FileNoMMap `state:"nosave"`
fsutil.FileNoSplice `state:"nosave"`
fsutil.FileNoopFlush `state:"nosave"`
fsutil.FileNoopFsync `state:"nosave"`
fsutil.FileNoopRead `state:"nosave"`
fsutil.FileNoopRelease `state:"nosave"`
fsutil.FileNoopWrite `state:"nosave"`
fsutil.FileNotDirReaddir `state:"nosave"`
fsutil.FileUseInodeUnstableAttr `state:"nosave"`
waiter.AlwaysReady `state:"nosave"`
}
var _ fs.FileOperations = (*nullFileOperations)(nil)
// +stateify savable
type zeroDevice struct {
nullDevice
}
var _ fs.InodeOperations = (*zeroDevice)(nil)
func newZeroDevice(ctx context.Context, owner fs.FileOwner, mode linux.FileMode) *zeroDevice {
zd := &zeroDevice{
nullDevice: nullDevice{
InodeSimpleAttributes: fsutil.NewInodeSimpleAttributes(ctx, owner, fs.FilePermsFromMode(mode), linux.TMPFS_MAGIC),
},
}
return zd
}
// GetFile implements fs.FileOperations.GetFile.
func (zd *zeroDevice) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags) (*fs.File, error) {
flags.Pread = true
flags.Pwrite = true
flags.NonSeekable = true
return fs.NewFile(ctx, dirent, flags, &zeroFileOperations{}), nil
}
// +stateify savable
type zeroFileOperations struct {
fsutil.FileGenericSeek `state:"nosave"`
fsutil.FileNoIoctl `state:"nosave"`
fsutil.FileNoSplice `state:"nosave"`
fsutil.FileNoopFlush `state:"nosave"`
fsutil.FileNoopFsync `state:"nosave"`
fsutil.FileNoopRelease `state:"nosave"`
fsutil.FileNoopWrite `state:"nosave"`
fsutil.FileNotDirReaddir `state:"nosave"`
fsutil.FileUseInodeUnstableAttr `state:"nosave"`
waiter.AlwaysReady `state:"nosave"`
readZeros `state:"nosave"`
}
var _ fs.FileOperations = (*zeroFileOperations)(nil)
// ConfigureMMap implements fs.FileOperations.ConfigureMMap.
func (*zeroFileOperations) ConfigureMMap(ctx context.Context, file *fs.File, opts *memmap.MMapOpts) error {
m, err := mm.NewSharedAnonMappable(opts.Length, pgalloc.MemoryFileProviderFromContext(ctx))
if err != nil {
return err
}
opts.MappingIdentity = m
opts.Mappable = m
return nil
}
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