1 files changed, 0 insertions, 592 deletions
diff --git a/pkg/sentry/fsimpl/memfs/filesystem.go b/pkg/sentry/fsimpl/memfs/filesystem.go
deleted file mode 100644
index 1f2a5122a..000000000
--- a/pkg/sentry/fsimpl/memfs/filesystem.go
+++ /dev/null
@@ -1,592 +0,0 @@
-// Copyright 2019 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 memfs
-
-import (
-	"fmt"
-	"sync/atomic"
-
-	"gvisor.dev/gvisor/pkg/abi/linux"
-	"gvisor.dev/gvisor/pkg/fspath"
-	"gvisor.dev/gvisor/pkg/sentry/context"
-	"gvisor.dev/gvisor/pkg/sentry/vfs"
-	"gvisor.dev/gvisor/pkg/syserror"
-)
-
-// stepLocked resolves rp.Component() in parent directory vfsd.
-//
-// stepLocked is loosely analogous to fs/namei.c:walk_component().
-//
-// Preconditions: filesystem.mu must be locked. !rp.Done(). inode ==
-// vfsd.Impl().(*dentry).inode.
-func stepLocked(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, inode *inode) (*vfs.Dentry, *inode, error) {
-	if !inode.isDir() {
-		return nil, nil, syserror.ENOTDIR
-	}
-	if err := inode.checkPermissions(rp.Credentials(), vfs.MayExec, true); err != nil {
-		return nil, nil, err
-	}
-afterSymlink:
-	nextVFSD, err := rp.ResolveComponent(vfsd)
-	if err != nil {
-		return nil, nil, err
-	}
-	if nextVFSD == nil {
-		// Since the Dentry tree is the sole source of truth for memfs, if it's
-		// not in the Dentry tree, it doesn't exist.
-		return nil, nil, syserror.ENOENT
-	}
-	nextInode := nextVFSD.Impl().(*dentry).inode
-	if symlink, ok := nextInode.impl.(*symlink); ok && rp.ShouldFollowSymlink() {
-		// TODO: symlink traversals update access time
-		if err := rp.HandleSymlink(symlink.target); err != nil {
-			return nil, nil, err
-		}
-		goto afterSymlink // don't check the current directory again
-	}
-	rp.Advance()
-	return nextVFSD, nextInode, nil
-}
-
-// walkExistingLocked resolves rp to an existing file.
-//
-// walkExistingLocked is loosely analogous to Linux's
-// fs/namei.c:path_lookupat().
-//
-// Preconditions: filesystem.mu must be locked.
-func walkExistingLocked(rp *vfs.ResolvingPath) (*vfs.Dentry, *inode, error) {
-	vfsd := rp.Start()
-	inode := vfsd.Impl().(*dentry).inode
-	for !rp.Done() {
-		var err error
-		vfsd, inode, err = stepLocked(rp, vfsd, inode)
-		if err != nil {
-			return nil, nil, err
-		}
-	}
-	if rp.MustBeDir() && !inode.isDir() {
-		return nil, nil, syserror.ENOTDIR
-	}
-	return vfsd, inode, nil
-}
-
-// walkParentDirLocked resolves all but the last path component of rp to an
-// existing directory. It does not check that the returned directory is
-// searchable by the provider of rp.
-//
-// walkParentDirLocked is loosely analogous to Linux's
-// fs/namei.c:path_parentat().
-//
-// Preconditions: filesystem.mu must be locked. !rp.Done().
-func walkParentDirLocked(rp *vfs.ResolvingPath) (*vfs.Dentry, *inode, error) {
-	vfsd := rp.Start()
-	inode := vfsd.Impl().(*dentry).inode
-	for !rp.Final() {
-		var err error
-		vfsd, inode, err = stepLocked(rp, vfsd, inode)
-		if err != nil {
-			return nil, nil, err
-		}
-	}
-	if !inode.isDir() {
-		return nil, nil, syserror.ENOTDIR
-	}
-	return vfsd, inode, nil
-}
-
-// checkCreateLocked checks that a file named rp.Component() may be created in
-// directory parentVFSD, then returns rp.Component().
-//
-// Preconditions: filesystem.mu must be locked. parentInode ==
-// parentVFSD.Impl().(*dentry).inode. parentInode.isDir() == true.
-func checkCreateLocked(rp *vfs.ResolvingPath, parentVFSD *vfs.Dentry, parentInode *inode) (string, error) {
-	if err := parentInode.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec, true); err != nil {
-		return "", err
-	}
-	pc := rp.Component()
-	if pc == "." || pc == ".." {
-		return "", syserror.EEXIST
-	}
-	childVFSD, err := rp.ResolveChild(parentVFSD, pc)
-	if err != nil {
-		return "", err
-	}
-	if childVFSD != nil {
-		return "", syserror.EEXIST
-	}
-	if parentVFSD.IsDisowned() {
-		return "", syserror.ENOENT
-	}
-	return pc, nil
-}
-
-// checkDeleteLocked checks that the file represented by vfsd may be deleted.
-func checkDeleteLocked(vfsd *vfs.Dentry) error {
-	parentVFSD := vfsd.Parent()
-	if parentVFSD == nil {
-		return syserror.EBUSY
-	}
-	if parentVFSD.IsDisowned() {
-		return syserror.ENOENT
-	}
-	return nil
-}
-
-// GetDentryAt implements vfs.FilesystemImpl.GetDentryAt.
-func (fs *filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.GetDentryOptions) (*vfs.Dentry, error) {
-	fs.mu.RLock()
-	defer fs.mu.RUnlock()
-	vfsd, inode, err := walkExistingLocked(rp)
-	if err != nil {
-		return nil, err
-	}
-	if opts.CheckSearchable {
-		if !inode.isDir() {
-			return nil, syserror.ENOTDIR
-		}
-		if err := inode.checkPermissions(rp.Credentials(), vfs.MayExec, true); err != nil {
-			return nil, err
-		}
-	}
-	inode.incRef()
-	return vfsd, nil
-}
-
-// LinkAt implements vfs.FilesystemImpl.LinkAt.
-func (fs *filesystem) LinkAt(ctx context.Context, rp *vfs.ResolvingPath, vd vfs.VirtualDentry) error {
-	if rp.Done() {
-		return syserror.EEXIST
-	}
-	fs.mu.Lock()
-	defer fs.mu.Unlock()
-	parentVFSD, parentInode, err := walkParentDirLocked(rp)
-	if err != nil {
-		return err
-	}
-	pc, err := checkCreateLocked(rp, parentVFSD, parentInode)
-	if err != nil {
-		return err
-	}
-	if rp.Mount() != vd.Mount() {
-		return syserror.EXDEV
-	}
-	if err := rp.Mount().CheckBeginWrite(); err != nil {
-		return err
-	}
-	defer rp.Mount().EndWrite()
-	d := vd.Dentry().Impl().(*dentry)
-	if d.inode.isDir() {
-		return syserror.EPERM
-	}
-	d.inode.incLinksLocked()
-	child := fs.newDentry(d.inode)
-	parentVFSD.InsertChild(&child.vfsd, pc)
-	parentInode.impl.(*directory).childList.PushBack(child)
-	return nil
-}
-
-// MkdirAt implements vfs.FilesystemImpl.MkdirAt.
-func (fs *filesystem) MkdirAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.MkdirOptions) error {
-	if rp.Done() {
-		return syserror.EEXIST
-	}
-	fs.mu.Lock()
-	defer fs.mu.Unlock()
-	parentVFSD, parentInode, err := walkParentDirLocked(rp)
-	if err != nil {
-		return err
-	}
-	pc, err := checkCreateLocked(rp, parentVFSD, parentInode)
-	if err != nil {
-		return err
-	}
-	if err := rp.Mount().CheckBeginWrite(); err != nil {
-		return err
-	}
-	defer rp.Mount().EndWrite()
-	child := fs.newDentry(fs.newDirectory(rp.Credentials(), opts.Mode))
-	parentVFSD.InsertChild(&child.vfsd, pc)
-	parentInode.impl.(*directory).childList.PushBack(child)
-	parentInode.incLinksLocked() // from child's ".."
-	return nil
-}
-
-// MknodAt implements vfs.FilesystemImpl.MknodAt.
-func (fs *filesystem) MknodAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.MknodOptions) error {
-	if rp.Done() {
-		return syserror.EEXIST
-	}
-	fs.mu.Lock()
-	defer fs.mu.Unlock()
-	parentVFSD, parentInode, err := walkParentDirLocked(rp)
-	if err != nil {
-		return err
-	}
-	pc, err := checkCreateLocked(rp, parentVFSD, parentInode)
-	if err != nil {
-		return err
-	}
-	if err := rp.Mount().CheckBeginWrite(); err != nil {
-		return err
-	}
-	defer rp.Mount().EndWrite()
-
-	switch opts.Mode.FileType() {
-	case 0:
-		// "Zero file type is equivalent to type S_IFREG." - mknod(2)
-		fallthrough
-	case linux.ModeRegular:
-		// TODO(b/138862511): Implement.
-		return syserror.EINVAL
-
-	case linux.ModeNamedPipe:
-		child := fs.newDentry(fs.newNamedPipe(rp.Credentials(), opts.Mode))
-		parentVFSD.InsertChild(&child.vfsd, pc)
-		parentInode.impl.(*directory).childList.PushBack(child)
-		return nil
-
-	case linux.ModeSocket:
-		// TODO(b/138862511): Implement.
-		return syserror.EINVAL
-
-	case linux.ModeCharacterDevice:
-		fallthrough
-	case linux.ModeBlockDevice:
-		// TODO(b/72101894): We don't support creating block or character
-		// devices at the moment.
-		//
-		// When we start supporting block and character devices, we'll
-		// need to check for CAP_MKNOD here.
-		return syserror.EPERM
-
-	default:
-		// "EINVAL - mode requested creation of something other than a
-		// regular file, device special file, FIFO or socket." - mknod(2)
-		return syserror.EINVAL
-	}
-}
-
-// OpenAt implements vfs.FilesystemImpl.OpenAt.
-func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
-	// Filter out flags that are not supported by memfs. O_DIRECTORY and
-	// O_NOFOLLOW have no effect here (they're handled by VFS by setting
-	// appropriate bits in rp), but are returned by
-	// FileDescriptionImpl.StatusFlags(). O_NONBLOCK is supported only by
-	// pipes.
-	opts.Flags &= linux.O_ACCMODE | linux.O_CREAT | linux.O_EXCL | linux.O_TRUNC | linux.O_DIRECTORY | linux.O_NOFOLLOW | linux.O_NONBLOCK
-
-	if opts.Flags&linux.O_CREAT == 0 {
-		fs.mu.RLock()
-		defer fs.mu.RUnlock()
-		vfsd, inode, err := walkExistingLocked(rp)
-		if err != nil {
-			return nil, err
-		}
-		return inode.open(ctx, rp, vfsd, opts.Flags, false)
-	}
-
-	mustCreate := opts.Flags&linux.O_EXCL != 0
-	vfsd := rp.Start()
-	inode := vfsd.Impl().(*dentry).inode
-	fs.mu.Lock()
-	defer fs.mu.Unlock()
-	if rp.Done() {
-		if rp.MustBeDir() {
-			return nil, syserror.EISDIR
-		}
-		if mustCreate {
-			return nil, syserror.EEXIST
-		}
-		return inode.open(ctx, rp, vfsd, opts.Flags, false)
-	}
-afterTrailingSymlink:
-	// Walk to the parent directory of the last path component.
-	for !rp.Final() {
-		var err error
-		vfsd, inode, err = stepLocked(rp, vfsd, inode)
-		if err != nil {
-			return nil, err
-		}
-	}
-	if !inode.isDir() {
-		return nil, syserror.ENOTDIR
-	}
-	// Check for search permission in the parent directory.
-	if err := inode.checkPermissions(rp.Credentials(), vfs.MayExec, true); err != nil {
-		return nil, err
-	}
-	// Reject attempts to open directories with O_CREAT.
-	if rp.MustBeDir() {
-		return nil, syserror.EISDIR
-	}
-	pc := rp.Component()
-	if pc == "." || pc == ".." {
-		return nil, syserror.EISDIR
-	}
-	// Determine whether or not we need to create a file.
-	childVFSD, err := rp.ResolveChild(vfsd, pc)
-	if err != nil {
-		return nil, err
-	}
-	if childVFSD == nil {
-		// Already checked for searchability above; now check for writability.
-		if err := inode.checkPermissions(rp.Credentials(), vfs.MayWrite, true); err != nil {
-			return nil, err
-		}
-		if err := rp.Mount().CheckBeginWrite(); err != nil {
-			return nil, err
-		}
-		defer rp.Mount().EndWrite()
-		// Create and open the child.
-		childInode := fs.newRegularFile(rp.Credentials(), opts.Mode)
-		child := fs.newDentry(childInode)
-		vfsd.InsertChild(&child.vfsd, pc)
-		inode.impl.(*directory).childList.PushBack(child)
-		return childInode.open(ctx, rp, &child.vfsd, opts.Flags, true)
-	}
-	// Open existing file or follow symlink.
-	if mustCreate {
-		return nil, syserror.EEXIST
-	}
-	childInode := childVFSD.Impl().(*dentry).inode
-	if symlink, ok := childInode.impl.(*symlink); ok && rp.ShouldFollowSymlink() {
-		// TODO: symlink traversals update access time
-		if err := rp.HandleSymlink(symlink.target); err != nil {
-			return nil, err
-		}
-		// rp.Final() may no longer be true since we now need to resolve the
-		// symlink target.
-		goto afterTrailingSymlink
-	}
-	return childInode.open(ctx, rp, childVFSD, opts.Flags, false)
-}
-
-func (i *inode) open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, flags uint32, afterCreate bool) (*vfs.FileDescription, error) {
-	ats := vfs.AccessTypesForOpenFlags(flags)
-	if !afterCreate {
-		if err := i.checkPermissions(rp.Credentials(), ats, i.isDir()); err != nil {
-			return nil, err
-		}
-	}
-	mnt := rp.Mount()
-	switch impl := i.impl.(type) {
-	case *regularFile:
-		var fd regularFileFD
-		fd.flags = flags
-		fd.readable = vfs.MayReadFileWithOpenFlags(flags)
-		fd.writable = vfs.MayWriteFileWithOpenFlags(flags)
-		if fd.writable {
-			if err := mnt.CheckBeginWrite(); err != nil {
-				return nil, err
-			}
-			// mnt.EndWrite() is called by regularFileFD.Release().
-		}
-		mnt.IncRef()
-		vfsd.IncRef()
-		fd.vfsfd.Init(&fd, mnt, vfsd)
-		if flags&linux.O_TRUNC != 0 {
-			impl.mu.Lock()
-			impl.data = impl.data[:0]
-			atomic.StoreInt64(&impl.dataLen, 0)
-			impl.mu.Unlock()
-		}
-		return &fd.vfsfd, nil
-	case *directory:
-		// Can't open directories writably.
-		if ats&vfs.MayWrite != 0 {
-			return nil, syserror.EISDIR
-		}
-		var fd directoryFD
-		mnt.IncRef()
-		vfsd.IncRef()
-		fd.vfsfd.Init(&fd, mnt, vfsd)
-		fd.flags = flags
-		return &fd.vfsfd, nil
-	case *symlink:
-		// Can't open symlinks without O_PATH (which is unimplemented).
-		return nil, syserror.ELOOP
-	case *namedPipe:
-		return newNamedPipeFD(ctx, impl, rp, vfsd, flags)
-	default:
-		panic(fmt.Sprintf("unknown inode type: %T", i.impl))
-	}
-}
-
-// ReadlinkAt implements vfs.FilesystemImpl.ReadlinkAt.
-func (fs *filesystem) ReadlinkAt(ctx context.Context, rp *vfs.ResolvingPath) (string, error) {
-	fs.mu.RLock()
-	_, inode, err := walkExistingLocked(rp)
-	fs.mu.RUnlock()
-	if err != nil {
-		return "", err
-	}
-	symlink, ok := inode.impl.(*symlink)
-	if !ok {
-		return "", syserror.EINVAL
-	}
-	return symlink.target, nil
-}
-
-// RenameAt implements vfs.FilesystemImpl.RenameAt.
-func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, vd vfs.VirtualDentry, opts vfs.RenameOptions) error {
-	if rp.Done() {
-		return syserror.ENOENT
-	}
-	fs.mu.Lock()
-	defer fs.mu.Unlock()
-	parentVFSD, parentInode, err := walkParentDirLocked(rp)
-	if err != nil {
-		return err
-	}
-	_, err = checkCreateLocked(rp, parentVFSD, parentInode)
-	if err != nil {
-		return err
-	}
-	if err := rp.Mount().CheckBeginWrite(); err != nil {
-		return err
-	}
-	defer rp.Mount().EndWrite()
-	// TODO: actually implement RenameAt
-	return syserror.EPERM
-}
-
-// RmdirAt implements vfs.FilesystemImpl.RmdirAt.
-func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error {
-	fs.mu.Lock()
-	defer fs.mu.Unlock()
-	vfsd, inode, err := walkExistingLocked(rp)
-	if err != nil {
-		return err
-	}
-	if err := rp.Mount().CheckBeginWrite(); err != nil {
-		return err
-	}
-	defer rp.Mount().EndWrite()
-	if err := checkDeleteLocked(vfsd); err != nil {
-		return err
-	}
-	if !inode.isDir() {
-		return syserror.ENOTDIR
-	}
-	if vfsd.HasChildren() {
-		return syserror.ENOTEMPTY
-	}
-	if err := rp.VirtualFilesystem().DeleteDentry(vfs.MountNamespaceFromContext(ctx), vfsd); err != nil {
-		return err
-	}
-	// Remove from parent directory's childList.
-	vfsd.Parent().Impl().(*dentry).inode.impl.(*directory).childList.Remove(vfsd.Impl().(*dentry))
-	inode.decRef()
-	return nil
-}
-
-// SetStatAt implements vfs.FilesystemImpl.SetStatAt.
-func (fs *filesystem) SetStatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.SetStatOptions) error {
-	fs.mu.RLock()
-	_, _, err := walkExistingLocked(rp)
-	fs.mu.RUnlock()
-	if err != nil {
-		return err
-	}
-	if opts.Stat.Mask == 0 {
-		return nil
-	}
-	// TODO: implement inode.setStat
-	return syserror.EPERM
-}
-
-// StatAt implements vfs.FilesystemImpl.StatAt.
-func (fs *filesystem) StatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.StatOptions) (linux.Statx, error) {
-	fs.mu.RLock()
-	_, inode, err := walkExistingLocked(rp)
-	fs.mu.RUnlock()
-	if err != nil {
-		return linux.Statx{}, err
-	}
-	var stat linux.Statx
-	inode.statTo(&stat)
-	return stat, nil
-}
-
-// StatFSAt implements vfs.FilesystemImpl.StatFSAt.
-func (fs *filesystem) StatFSAt(ctx context.Context, rp *vfs.ResolvingPath) (linux.Statfs, error) {
-	fs.mu.RLock()
-	_, _, err := walkExistingLocked(rp)
-	fs.mu.RUnlock()
-	if err != nil {
-		return linux.Statfs{}, err
-	}
-	// TODO: actually implement statfs
-	return linux.Statfs{}, syserror.ENOSYS
-}
-
-// SymlinkAt implements vfs.FilesystemImpl.SymlinkAt.
-func (fs *filesystem) SymlinkAt(ctx context.Context, rp *vfs.ResolvingPath, target string) error {
-	if rp.Done() {
-		return syserror.EEXIST
-	}
-	fs.mu.Lock()
-	defer fs.mu.Unlock()
-	parentVFSD, parentInode, err := walkParentDirLocked(rp)
-	if err != nil {
-		return err
-	}
-	pc, err := checkCreateLocked(rp, parentVFSD, parentInode)
-	if err != nil {
-		return err
-	}
-	if err := rp.Mount().CheckBeginWrite(); err != nil {
-		return err
-	}
-	defer rp.Mount().EndWrite()
-	child := fs.newDentry(fs.newSymlink(rp.Credentials(), target))
-	parentVFSD.InsertChild(&child.vfsd, pc)
-	parentInode.impl.(*directory).childList.PushBack(child)
-	return nil
-}
-
-// UnlinkAt implements vfs.FilesystemImpl.UnlinkAt.
-func (fs *filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error {
-	fs.mu.Lock()
-	defer fs.mu.Unlock()
-	vfsd, inode, err := walkExistingLocked(rp)
-	if err != nil {
-		return err
-	}
-	if err := rp.Mount().CheckBeginWrite(); err != nil {
-		return err
-	}
-	defer rp.Mount().EndWrite()
-	if err := checkDeleteLocked(vfsd); err != nil {
-		return err
-	}
-	if inode.isDir() {
-		return syserror.EISDIR
-	}
-	if err := rp.VirtualFilesystem().DeleteDentry(vfs.MountNamespaceFromContext(ctx), vfsd); err != nil {
-		return err
-	}
-	// Remove from parent directory's childList.
-	vfsd.Parent().Impl().(*dentry).inode.impl.(*directory).childList.Remove(vfsd.Impl().(*dentry))
-	inode.decLinksLocked()
-	return nil
-}
-
-// PrependPath implements vfs.FilesystemImpl.PrependPath.
-func (fs *filesystem) PrependPath(ctx context.Context, vfsroot, vd vfs.VirtualDentry, b *fspath.Builder) error {
-	fs.mu.RLock()
-	defer fs.mu.RUnlock()
-	return vfs.GenericPrependPath(vfsroot, vd, b)
-}