Merge 216da0b7 (automated)

1 files changed, 503 insertions, 0 deletions

diff --git a/pkg/sentry/fs/fsutil/inode.go b/pkg/sentry/fs/fsutil/inode.go
new file mode 100644
index 000000000..925887335
--- /dev/null
+++ b/pkg/sentry/fs/fsutil/inode.go
@@ -0,0 +1,503 @@
+// 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 fsutil
+
+import (
+	"sync"
+
+	"gvisor.googlesource.com/gvisor/pkg/sentry/context"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
+	ktime "gvisor.googlesource.com/gvisor/pkg/sentry/kernel/time"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/memmap"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/socket/unix/transport"
+	"gvisor.googlesource.com/gvisor/pkg/syserror"
+	"gvisor.googlesource.com/gvisor/pkg/waiter"
+)
+
+// SimpleFileInode is a simple implementation of InodeOperations.
+//
+// +stateify savable
+type SimpleFileInode struct {
+	InodeGenericChecker       `state:"nosave"`
+	InodeNoExtendedAttributes `state:"nosave"`
+	InodeNoopRelease          `state:"nosave"`
+	InodeNoopWriteOut         `state:"nosave"`
+	InodeNotAllocatable       `state:"nosave"`
+	InodeNotDirectory         `state:"nosave"`
+	InodeNotMappable          `state:"nosave"`
+	InodeNotOpenable          `state:"nosave"`
+	InodeNotSocket            `state:"nosave"`
+	InodeNotSymlink           `state:"nosave"`
+	InodeNotTruncatable       `state:"nosave"`
+	InodeNotVirtual           `state:"nosave"`
+
+	InodeSimpleAttributes
+}
+
+// NewSimpleFileInode returns a new SimpleFileInode.
+func NewSimpleFileInode(ctx context.Context, owner fs.FileOwner, perms fs.FilePermissions, typ uint64) *SimpleFileInode {
+	return &SimpleFileInode{
+		InodeSimpleAttributes: NewInodeSimpleAttributes(ctx, owner, perms, typ),
+	}
+}
+
+// NoReadWriteFileInode is an implementation of InodeOperations that supports
+// opening files that are not readable or writeable.
+//
+// +stateify savable
+type NoReadWriteFileInode struct {
+	InodeGenericChecker       `state:"nosave"`
+	InodeNoExtendedAttributes `state:"nosave"`
+	InodeNoopRelease          `state:"nosave"`
+	InodeNoopWriteOut         `state:"nosave"`
+	InodeNotAllocatable       `state:"nosave"`
+	InodeNotDirectory         `state:"nosave"`
+	InodeNotMappable          `state:"nosave"`
+	InodeNotSocket            `state:"nosave"`
+	InodeNotSymlink           `state:"nosave"`
+	InodeNotTruncatable       `state:"nosave"`
+	InodeNotVirtual           `state:"nosave"`
+
+	InodeSimpleAttributes
+}
+
+// NewNoReadWriteFileInode returns a new NoReadWriteFileInode.
+func NewNoReadWriteFileInode(ctx context.Context, owner fs.FileOwner, perms fs.FilePermissions, typ uint64) *NoReadWriteFileInode {
+	return &NoReadWriteFileInode{
+		InodeSimpleAttributes: NewInodeSimpleAttributes(ctx, owner, perms, typ),
+	}
+}
+
+// GetFile implements fs.InodeOperations.GetFile.
+func (*NoReadWriteFileInode) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags) (*fs.File, error) {
+	return fs.NewFile(ctx, dirent, flags, &NoReadWriteFile{}), nil
+}
+
+// InodeSimpleAttributes implements methods for updating in-memory unstable
+// attributes.
+//
+// +stateify savable
+type InodeSimpleAttributes struct {
+	// fsType is the immutable filesystem type that will be returned by
+	// StatFS.
+	fsType uint64
+
+	// mu protects unstable.
+	mu       sync.RWMutex `state:"nosave"`
+	unstable fs.UnstableAttr
+}
+
+// NewInodeSimpleAttributes returns a new InodeSimpleAttributes with the given
+// owner and permissions, and all timestamps set to the current time.
+func NewInodeSimpleAttributes(ctx context.Context, owner fs.FileOwner, perms fs.FilePermissions, typ uint64) InodeSimpleAttributes {
+	return NewInodeSimpleAttributesWithUnstable(fs.WithCurrentTime(ctx, fs.UnstableAttr{
+		Owner: owner,
+		Perms: perms,
+	}), typ)
+}
+
+// NewInodeSimpleAttributesWithUnstable returns a new InodeSimpleAttributes
+// with the given unstable attributes.
+func NewInodeSimpleAttributesWithUnstable(uattr fs.UnstableAttr, typ uint64) InodeSimpleAttributes {
+	return InodeSimpleAttributes{
+		fsType:   typ,
+		unstable: uattr,
+	}
+}
+
+// UnstableAttr implements fs.InodeOperations.UnstableAttr.
+func (i *InodeSimpleAttributes) UnstableAttr(ctx context.Context, _ *fs.Inode) (fs.UnstableAttr, error) {
+	i.mu.RLock()
+	u := i.unstable
+	i.mu.RUnlock()
+	return u, nil
+}
+
+// SetPermissions implements fs.InodeOperations.SetPermissions.
+func (i *InodeSimpleAttributes) SetPermissions(ctx context.Context, _ *fs.Inode, p fs.FilePermissions) bool {
+	i.mu.Lock()
+	i.unstable.SetPermissions(ctx, p)
+	i.mu.Unlock()
+	return true
+}
+
+// SetOwner implements fs.InodeOperations.SetOwner.
+func (i *InodeSimpleAttributes) SetOwner(ctx context.Context, _ *fs.Inode, owner fs.FileOwner) error {
+	i.mu.Lock()
+	i.unstable.SetOwner(ctx, owner)
+	i.mu.Unlock()
+	return nil
+}
+
+// SetTimestamps implements fs.InodeOperations.SetTimestamps.
+func (i *InodeSimpleAttributes) SetTimestamps(ctx context.Context, _ *fs.Inode, ts fs.TimeSpec) error {
+	i.mu.Lock()
+	i.unstable.SetTimestamps(ctx, ts)
+	i.mu.Unlock()
+	return nil
+}
+
+// AddLink implements fs.InodeOperations.AddLink.
+func (i *InodeSimpleAttributes) AddLink() {
+	i.mu.Lock()
+	i.unstable.Links++
+	i.mu.Unlock()
+}
+
+// DropLink implements fs.InodeOperations.DropLink.
+func (i *InodeSimpleAttributes) DropLink() {
+	i.mu.Lock()
+	i.unstable.Links--
+	i.mu.Unlock()
+}
+
+// StatFS implements fs.InodeOperations.StatFS.
+func (i *InodeSimpleAttributes) StatFS(context.Context) (fs.Info, error) {
+	if i.fsType == 0 {
+		return fs.Info{}, syserror.ENOSYS
+	}
+	return fs.Info{Type: i.fsType}, nil
+}
+
+// NotifyAccess updates the access time.
+func (i *InodeSimpleAttributes) NotifyAccess(ctx context.Context) {
+	i.mu.Lock()
+	i.unstable.AccessTime = ktime.NowFromContext(ctx)
+	i.mu.Unlock()
+}
+
+// NotifyModification updates the modification time.
+func (i *InodeSimpleAttributes) NotifyModification(ctx context.Context) {
+	i.mu.Lock()
+	i.unstable.ModificationTime = ktime.NowFromContext(ctx)
+	i.mu.Unlock()
+}
+
+// NotifyStatusChange updates the status change time.
+func (i *InodeSimpleAttributes) NotifyStatusChange(ctx context.Context) {
+	i.mu.Lock()
+	i.unstable.StatusChangeTime = ktime.NowFromContext(ctx)
+	i.mu.Unlock()
+}
+
+// NotifyModificationAndStatusChange updates the modification and status change
+// times.
+func (i *InodeSimpleAttributes) NotifyModificationAndStatusChange(ctx context.Context) {
+	i.mu.Lock()
+	now := ktime.NowFromContext(ctx)
+	i.unstable.ModificationTime = now
+	i.unstable.StatusChangeTime = now
+	i.mu.Unlock()
+}
+
+// InodeSimpleExtendedAttributes implements
+// fs.InodeOperations.{Get,Set,List}xattr.
+//
+// +stateify savable
+type InodeSimpleExtendedAttributes struct {
+	// mu protects xattrs.
+	mu     sync.RWMutex `state:"nosave"`
+	xattrs map[string]string
+}
+
+// Getxattr implements fs.InodeOperations.Getxattr.
+func (i *InodeSimpleExtendedAttributes) Getxattr(_ *fs.Inode, name string) (string, error) {
+	i.mu.RLock()
+	value, ok := i.xattrs[name]
+	i.mu.RUnlock()
+	if !ok {
+		return "", syserror.ENOATTR
+	}
+	return value, nil
+}
+
+// Setxattr implements fs.InodeOperations.Setxattr.
+func (i *InodeSimpleExtendedAttributes) Setxattr(_ *fs.Inode, name, value string) error {
+	i.mu.Lock()
+	if i.xattrs == nil {
+		i.xattrs = make(map[string]string)
+	}
+	i.xattrs[name] = value
+	i.mu.Unlock()
+	return nil
+}
+
+// Listxattr implements fs.InodeOperations.Listxattr.
+func (i *InodeSimpleExtendedAttributes) Listxattr(_ *fs.Inode) (map[string]struct{}, error) {
+	i.mu.RLock()
+	names := make(map[string]struct{}, len(i.xattrs))
+	for name := range i.xattrs {
+		names[name] = struct{}{}
+	}
+	i.mu.RUnlock()
+	return names, nil
+}
+
+// staticFile is a file with static contents. It is returned by
+// InodeStaticFileGetter.GetFile.
+//
+// +stateify savable
+type staticFile struct {
+	FileGenericSeek          `state:"nosave"`
+	FileNoIoctl              `state:"nosave"`
+	FileNoMMap               `state:"nosave"`
+	FileNoSplice             `state:"nosave"`
+	FileNoopFsync            `state:"nosave"`
+	FileNoopFlush            `state:"nosave"`
+	FileNoopRelease          `state:"nosave"`
+	FileNoopWrite            `state:"nosave"`
+	FileNotDirReaddir        `state:"nosave"`
+	FileUseInodeUnstableAttr `state:"nosave"`
+	waiter.AlwaysReady       `state:"nosave"`
+
+	FileStaticContentReader
+}
+
+// InodeNoStatFS implement StatFS by retuning ENOSYS.
+type InodeNoStatFS struct{}
+
+// StatFS implements fs.InodeOperations.StatFS.
+func (InodeNoStatFS) StatFS(context.Context) (fs.Info, error) {
+	return fs.Info{}, syserror.ENOSYS
+}
+
+// InodeStaticFileGetter implements GetFile for a file with static contents.
+//
+// +stateify savable
+type InodeStaticFileGetter struct {
+	Contents []byte
+}
+
+// GetFile implements fs.InodeOperations.GetFile.
+func (i *InodeStaticFileGetter) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags) (*fs.File, error) {
+	return fs.NewFile(ctx, dirent, flags, &staticFile{
+		FileStaticContentReader: NewFileStaticContentReader(i.Contents),
+	}), nil
+}
+
+// InodeNotMappable returns a nil memmap.Mappable.
+type InodeNotMappable struct{}
+
+// Mappable implements fs.InodeOperations.Mappable.
+func (InodeNotMappable) Mappable(*fs.Inode) memmap.Mappable {
+	return nil
+}
+
+// InodeNoopWriteOut is a no-op implementation of fs.InodeOperations.WriteOut.
+type InodeNoopWriteOut struct{}
+
+// WriteOut is a no-op.
+func (InodeNoopWriteOut) WriteOut(context.Context, *fs.Inode) error {
+	return nil
+}
+
+// InodeNotDirectory can be used by Inodes that are not directories.
+type InodeNotDirectory struct{}
+
+// Lookup implements fs.InodeOperations.Lookup.
+func (InodeNotDirectory) Lookup(context.Context, *fs.Inode, string) (*fs.Dirent, error) {
+	return nil, syserror.ENOTDIR
+}
+
+// Create implements fs.InodeOperations.Create.
+func (InodeNotDirectory) Create(context.Context, *fs.Inode, string, fs.FileFlags, fs.FilePermissions) (*fs.File, error) {
+	return nil, syserror.ENOTDIR
+}
+
+// CreateLink implements fs.InodeOperations.CreateLink.
+func (InodeNotDirectory) CreateLink(context.Context, *fs.Inode, string, string) error {
+	return syserror.ENOTDIR
+}
+
+// CreateHardLink implements fs.InodeOperations.CreateHardLink.
+func (InodeNotDirectory) CreateHardLink(context.Context, *fs.Inode, *fs.Inode, string) error {
+	return syserror.ENOTDIR
+}
+
+// CreateDirectory implements fs.InodeOperations.CreateDirectory.
+func (InodeNotDirectory) CreateDirectory(context.Context, *fs.Inode, string, fs.FilePermissions) error {
+	return syserror.ENOTDIR
+}
+
+// Bind implements fs.InodeOperations.Bind.
+func (InodeNotDirectory) Bind(context.Context, *fs.Inode, string, transport.BoundEndpoint, fs.FilePermissions) (*fs.Dirent, error) {
+	return nil, syserror.ENOTDIR
+}
+
+// CreateFifo implements fs.InodeOperations.CreateFifo.
+func (InodeNotDirectory) CreateFifo(context.Context, *fs.Inode, string, fs.FilePermissions) error {
+	return syserror.ENOTDIR
+}
+
+// Remove implements fs.InodeOperations.Remove.
+func (InodeNotDirectory) Remove(context.Context, *fs.Inode, string) error {
+	return syserror.ENOTDIR
+}
+
+// RemoveDirectory implements fs.InodeOperations.RemoveDirectory.
+func (InodeNotDirectory) RemoveDirectory(context.Context, *fs.Inode, string) error {
+	return syserror.ENOTDIR
+}
+
+// Rename implements fs.FileOperations.Rename.
+func (InodeNotDirectory) Rename(context.Context, *fs.Inode, *fs.Inode, string, *fs.Inode, string, bool) error {
+	return syserror.EINVAL
+}
+
+// InodeNotSocket can be used by Inodes that are not sockets.
+type InodeNotSocket struct{}
+
+// BoundEndpoint implements fs.InodeOperations.BoundEndpoint.
+func (InodeNotSocket) BoundEndpoint(*fs.Inode, string) transport.BoundEndpoint {
+	return nil
+}
+
+// InodeNotTruncatable can be used by Inodes that cannot be truncated.
+type InodeNotTruncatable struct{}
+
+// Truncate implements fs.InodeOperations.Truncate.
+func (InodeNotTruncatable) Truncate(context.Context, *fs.Inode, int64) error {
+	return syserror.EINVAL
+}
+
+// InodeIsDirTruncate implements fs.InodeOperations.Truncate for directories.
+type InodeIsDirTruncate struct{}
+
+// Truncate implements fs.InodeOperations.Truncate.
+func (InodeIsDirTruncate) Truncate(context.Context, *fs.Inode, int64) error {
+	return syserror.EISDIR
+}
+
+// InodeNoopTruncate implements fs.InodeOperations.Truncate as a noop.
+type InodeNoopTruncate struct{}
+
+// Truncate implements fs.InodeOperations.Truncate.
+func (InodeNoopTruncate) Truncate(context.Context, *fs.Inode, int64) error {
+	return nil
+}
+
+// InodeNotRenameable can be used by Inodes that cannot be truncated.
+type InodeNotRenameable struct{}
+
+// Rename implements fs.InodeOperations.Rename.
+func (InodeNotRenameable) Rename(context.Context, *fs.Inode, *fs.Inode, string, *fs.Inode, string, bool) error {
+	return syserror.EINVAL
+}
+
+// InodeNotOpenable can be used by Inodes that cannot be opened.
+type InodeNotOpenable struct{}
+
+// GetFile implements fs.InodeOperations.GetFile.
+func (InodeNotOpenable) GetFile(context.Context, *fs.Dirent, fs.FileFlags) (*fs.File, error) {
+	return nil, syserror.EIO
+}
+
+// InodeNotVirtual can be used by Inodes that are not virtual.
+type InodeNotVirtual struct{}
+
+// IsVirtual implements fs.InodeOperations.IsVirtual.
+func (InodeNotVirtual) IsVirtual() bool {
+	return false
+}
+
+// InodeVirtual can be used by Inodes that are virtual.
+type InodeVirtual struct{}
+
+// IsVirtual implements fs.InodeOperations.IsVirtual.
+func (InodeVirtual) IsVirtual() bool {
+	return true
+}
+
+// InodeNotSymlink can be used by Inodes that are not symlinks.
+type InodeNotSymlink struct{}
+
+// Readlink implements fs.InodeOperations.Readlink.
+func (InodeNotSymlink) Readlink(context.Context, *fs.Inode) (string, error) {
+	return "", syserror.ENOLINK
+}
+
+// Getlink implements fs.InodeOperations.Getlink.
+func (InodeNotSymlink) Getlink(context.Context, *fs.Inode) (*fs.Dirent, error) {
+	return nil, syserror.ENOLINK
+}
+
+// InodeNoExtendedAttributes can be used by Inodes that do not support
+// extended attributes.
+type InodeNoExtendedAttributes struct{}
+
+// Getxattr implements fs.InodeOperations.Getxattr.
+func (InodeNoExtendedAttributes) Getxattr(*fs.Inode, string) (string, error) {
+	return "", syserror.EOPNOTSUPP
+}
+
+// Setxattr implements fs.InodeOperations.Setxattr.
+func (InodeNoExtendedAttributes) Setxattr(*fs.Inode, string, string) error {
+	return syserror.EOPNOTSUPP
+}
+
+// Listxattr implements fs.InodeOperations.Listxattr.
+func (InodeNoExtendedAttributes) Listxattr(*fs.Inode) (map[string]struct{}, error) {
+	return nil, syserror.EOPNOTSUPP
+}
+
+// InodeNoopRelease implements fs.InodeOperations.Release as a noop.
+type InodeNoopRelease struct{}
+
+// Release implements fs.InodeOperations.Release.
+func (InodeNoopRelease) Release(context.Context) {}
+
+// InodeGenericChecker implements fs.InodeOperations.Check with a generic
+// implementation.
+type InodeGenericChecker struct{}
+
+// Check implements fs.InodeOperations.Check.
+func (InodeGenericChecker) Check(ctx context.Context, inode *fs.Inode, p fs.PermMask) bool {
+	return fs.ContextCanAccessFile(ctx, inode, p)
+}
+
+// InodeDenyWriteChecker implements fs.InodeOperations.Check which denies all
+// write operations.
+type InodeDenyWriteChecker struct{}
+
+// Check implements fs.InodeOperations.Check.
+func (InodeDenyWriteChecker) Check(ctx context.Context, inode *fs.Inode, p fs.PermMask) bool {
+	if p.Write {
+		return false
+	}
+	return fs.ContextCanAccessFile(ctx, inode, p)
+}
+
+//InodeNotAllocatable can be used by Inodes that do not support Allocate().
+type InodeNotAllocatable struct{}
+
+func (InodeNotAllocatable) Allocate(_ context.Context, _ *fs.Inode, _, _ int64) error {
+	return syserror.EOPNOTSUPP
+}
+
+// InodeNoopAllocate implements fs.InodeOperations.Allocate as a noop.
+type InodeNoopAllocate struct{}
+
+// Allocate implements fs.InodeOperations.Allocate.
+func (InodeNoopAllocate) Allocate(_ context.Context, _ *fs.Inode, _, _ int64) error {
+	return nil
+}
+
+// InodeIsDirAllocate implements fs.InodeOperations.Allocate for directories.
+type InodeIsDirAllocate struct{}
+
+// Allocate implements fs.InodeOperations.Allocate.
+func (InodeIsDirAllocate) Allocate(_ context.Context, _ *fs.Inode, _, _ int64) error {
+	return syserror.EISDIR
+}