diff options
Diffstat (limited to 'pkg/sentry/fs')
| -rw-r--r-- | pkg/sentry/fs/overlay.go | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/pkg/sentry/fs/overlay.go b/pkg/sentry/fs/overlay.go index 40eed3feb..90d21642e 100644 --- a/pkg/sentry/fs/overlay.go +++ b/pkg/sentry/fs/overlay.go @@ -103,6 +103,28 @@ func NewOverlayRoot(ctx context.Context, upper *Inode, lower *Inode, flags Mount return newOverlayInode(ctx, overlay, msrc), nil } +// NewOverlayRootFile produces the root of an overlay that points to a file. +// +// Preconditions: +// +// - lower must be non-nil. +// - lower should not expose character devices, pipes, or sockets, because +// copying up these types of files is not supported. Neither it can be a dir. +// - lower must not require that file objects be revalidated. +// - lower must not have dynamic file/directory content. +func NewOverlayRootFile(ctx context.Context, upperMS *MountSource, lower *Inode, flags MountSourceFlags) (*Inode, error) { + if IsRegular(lower.StableAttr) { + return nil, fmt.Errorf("lower Inode is not a regular file") + } + msrc := newOverlayMountSource(upperMS, lower.MountSource, flags) + overlay, err := newOverlayEntry(ctx, nil, lower, true) + if err != nil { + msrc.DecRef() + return nil, err + } + return newOverlayInode(ctx, overlay, msrc), nil +} + // newOverlayInode creates a new Inode for an overlay. func newOverlayInode(ctx context.Context, o *overlayEntry, msrc *MountSource) *Inode { var inode *Inode |