diff options
Diffstat (limited to 'pkg/sentry/fsimpl/kernfs')
| -rw-r--r-- | pkg/sentry/fsimpl/kernfs/kernfs_state_autogen.go | 56 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/kernfs/mmap_util.go | 164 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/kernfs/save_restore.go | 23 |
3 files changed, 243 insertions, 0 deletions
diff --git a/pkg/sentry/fsimpl/kernfs/kernfs_state_autogen.go b/pkg/sentry/fsimpl/kernfs/kernfs_state_autogen.go index 1a62f05aa..9bac6798d 100644 --- a/pkg/sentry/fsimpl/kernfs/kernfs_state_autogen.go +++ b/pkg/sentry/fsimpl/kernfs/kernfs_state_autogen.go @@ -664,6 +664,60 @@ func (d *Dentry) StateLoad(stateSourceObject state.Source) { stateSourceObject.Load(9, &d.inode) } +func (i *inodePlatformFile) StateTypeName() string { + return "pkg/sentry/fsimpl/kernfs.inodePlatformFile" +} + +func (i *inodePlatformFile) StateFields() []string { + return []string{ + "hostFD", + "fdRefs", + "fileMapper", + } +} + +func (i *inodePlatformFile) beforeSave() {} + +func (i *inodePlatformFile) StateSave(stateSinkObject state.Sink) { + i.beforeSave() + stateSinkObject.Save(0, &i.hostFD) + stateSinkObject.Save(1, &i.fdRefs) + stateSinkObject.Save(2, &i.fileMapper) +} + +func (i *inodePlatformFile) StateLoad(stateSourceObject state.Source) { + stateSourceObject.Load(0, &i.hostFD) + stateSourceObject.Load(1, &i.fdRefs) + stateSourceObject.Load(2, &i.fileMapper) + stateSourceObject.AfterLoad(i.afterLoad) +} + +func (i *CachedMappable) StateTypeName() string { + return "pkg/sentry/fsimpl/kernfs.CachedMappable" +} + +func (i *CachedMappable) StateFields() []string { + return []string{ + "mappings", + "pf", + } +} + +func (i *CachedMappable) beforeSave() {} + +func (i *CachedMappable) StateSave(stateSinkObject state.Sink) { + i.beforeSave() + stateSinkObject.Save(0, &i.mappings) + stateSinkObject.Save(1, &i.pf) +} + +func (i *CachedMappable) afterLoad() {} + +func (i *CachedMappable) StateLoad(stateSourceObject state.Source) { + stateSourceObject.Load(0, &i.mappings) + stateSourceObject.Load(1, &i.pf) +} + func (l *slotList) StateTypeName() string { return "pkg/sentry/fsimpl/kernfs.slotList" } @@ -860,6 +914,8 @@ func init() { state.Register((*InodeNoStatFS)(nil)) state.Register((*Filesystem)(nil)) state.Register((*Dentry)(nil)) + state.Register((*inodePlatformFile)(nil)) + state.Register((*CachedMappable)(nil)) state.Register((*slotList)(nil)) state.Register((*slotEntry)(nil)) state.Register((*StaticDirectoryRefs)(nil)) diff --git a/pkg/sentry/fsimpl/kernfs/mmap_util.go b/pkg/sentry/fsimpl/kernfs/mmap_util.go new file mode 100644 index 000000000..bd6a134b4 --- /dev/null +++ b/pkg/sentry/fsimpl/kernfs/mmap_util.go @@ -0,0 +1,164 @@ +// 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 kernfs + +import ( + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/safemem" + "gvisor.dev/gvisor/pkg/sentry/fs/fsutil" + "gvisor.dev/gvisor/pkg/sentry/memmap" + "gvisor.dev/gvisor/pkg/sync" + "gvisor.dev/gvisor/pkg/usermem" +) + +// inodePlatformFile implements memmap.File. It exists solely because inode +// cannot implement both kernfs.Inode.IncRef and memmap.File.IncRef. +// +// +stateify savable +type inodePlatformFile struct { + // hostFD contains the host fd that this file was originally created from, + // which must be available at time of restore. + // + // This field is initialized at creation time and is immutable. + // inodePlatformFile does not own hostFD and hence should not close it. + hostFD int + + // fdRefsMu protects fdRefs. + fdRefsMu sync.Mutex `state:"nosave"` + + // fdRefs counts references on memmap.File offsets. It is used solely for + // memory accounting. + fdRefs fsutil.FrameRefSet + + // fileMapper caches mappings of the host file represented by this inode. + fileMapper fsutil.HostFileMapper + + // fileMapperInitOnce is used to lazily initialize fileMapper. + fileMapperInitOnce sync.Once `state:"nosave"` +} + +var _ memmap.File = (*inodePlatformFile)(nil) + +// IncRef implements memmap.File.IncRef. +func (i *inodePlatformFile) IncRef(fr memmap.FileRange) { + i.fdRefsMu.Lock() + i.fdRefs.IncRefAndAccount(fr) + i.fdRefsMu.Unlock() +} + +// DecRef implements memmap.File.DecRef. +func (i *inodePlatformFile) DecRef(fr memmap.FileRange) { + i.fdRefsMu.Lock() + i.fdRefs.DecRefAndAccount(fr) + i.fdRefsMu.Unlock() +} + +// MapInternal implements memmap.File.MapInternal. +func (i *inodePlatformFile) MapInternal(fr memmap.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) { + return i.fileMapper.MapInternal(fr, i.hostFD, at.Write) +} + +// FD implements memmap.File.FD. +func (i *inodePlatformFile) FD() int { + return i.hostFD +} + +// CachedMappable implements memmap.Mappable. This utility can be embedded in a +// kernfs.Inode that represents a host file to make the inode mappable. +// CachedMappable caches the mappings of the host file. CachedMappable must be +// initialized (via Init) with a hostFD before use. +// +// +stateify savable +type CachedMappable struct { + // mapsMu protects mappings. + mapsMu sync.Mutex `state:"nosave"` + + // mappings tracks mappings of hostFD into memmap.MappingSpaces. + mappings memmap.MappingSet + + // pf implements memmap.File for mappings backed by a host fd. + pf inodePlatformFile +} + +var _ memmap.Mappable = (*CachedMappable)(nil) + +// Init initializes i.pf. This must be called before using CachedMappable. +func (i *CachedMappable) Init(hostFD int) { + i.pf.hostFD = hostFD +} + +// AddMapping implements memmap.Mappable.AddMapping. +func (i *CachedMappable) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64, writable bool) error { + i.mapsMu.Lock() + mapped := i.mappings.AddMapping(ms, ar, offset, writable) + for _, r := range mapped { + i.pf.fileMapper.IncRefOn(r) + } + i.mapsMu.Unlock() + return nil +} + +// RemoveMapping implements memmap.Mappable.RemoveMapping. +func (i *CachedMappable) RemoveMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64, writable bool) { + i.mapsMu.Lock() + unmapped := i.mappings.RemoveMapping(ms, ar, offset, writable) + for _, r := range unmapped { + i.pf.fileMapper.DecRefOn(r) + } + i.mapsMu.Unlock() +} + +// CopyMapping implements memmap.Mappable.CopyMapping. +func (i *CachedMappable) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, dstAR usermem.AddrRange, offset uint64, writable bool) error { + return i.AddMapping(ctx, ms, dstAR, offset, writable) +} + +// Translate implements memmap.Mappable.Translate. +func (i *CachedMappable) Translate(ctx context.Context, required, optional memmap.MappableRange, at usermem.AccessType) ([]memmap.Translation, error) { + mr := optional + return []memmap.Translation{ + { + Source: mr, + File: &i.pf, + Offset: mr.Start, + Perms: usermem.AnyAccess, + }, + }, nil +} + +// InvalidateUnsavable implements memmap.Mappable.InvalidateUnsavable. +func (i *CachedMappable) InvalidateUnsavable(ctx context.Context) error { + // We expect the same host fd across save/restore, so all translations + // should be valid. + return nil +} + +// InvalidateRange invalidates the passed range on i.mappings. +func (i *CachedMappable) InvalidateRange(r memmap.MappableRange) { + i.mapsMu.Lock() + i.mappings.Invalidate(r, memmap.InvalidateOpts{ + // Compare Linux's mm/truncate.c:truncate_setsize() => + // truncate_pagecache() => + // mm/memory.c:unmap_mapping_range(evencows=1). + InvalidatePrivate: true, + }) + i.mapsMu.Unlock() +} + +// InitFileMapperOnce initializes the host file mapper. It ensures that the +// file mapper is initialized just once. +func (i *CachedMappable) InitFileMapperOnce() { + i.pf.fileMapperInitOnce.Do(i.pf.fileMapper.Init) +} diff --git a/pkg/sentry/fsimpl/kernfs/save_restore.go b/pkg/sentry/fsimpl/kernfs/save_restore.go new file mode 100644 index 000000000..1f48de6f1 --- /dev/null +++ b/pkg/sentry/fsimpl/kernfs/save_restore.go @@ -0,0 +1,23 @@ +// 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 kernfs + +// afterLoad is invoked by stateify. +func (i *inodePlatformFile) afterLoad() { + if i.fileMapper.IsInited() { + // Ensure that we don't call i.fileMapper.Init() again. + i.fileMapperInitOnce.Do(func() {}) + } +} |