Fixes for procfs

- Return ENOENT for /proc/[pid]/task if task is zoombied or terminated
- Allow directory to be Seek() to the end
- Construct synthetic files for /proc/[pid]/ns/*
- Changed GenericDirectoryFD.Init to not register with FileDescription,
  otherwise other implementation cannot change behavior.

Updates #1195,1193

PiperOrigin-RevId: 308294649

1 files changed, 8 insertions, 0 deletions

diff --git a/pkg/sentry/vfs/vfs.go b/pkg/sentry/vfs/vfs.go
index cb5bbd781..9015f2cc1 100644
--- a/pkg/sentry/vfs/vfs.go
+++ b/pkg/sentry/vfs/vfs.go
@@ -797,6 +797,14 @@ type VirtualDentry struct {
 	dentry *Dentry
 }
 
+// MakeVirtualDentry creates a VirtualDentry.
+func MakeVirtualDentry(mount *Mount, dentry *Dentry) VirtualDentry {
+	return VirtualDentry{
+		mount:  mount,
+		dentry: dentry,
+	}
+}
+
 // Ok returns true if vd is not empty. It does not require that a reference is
 // held.
 func (vd VirtualDentry) Ok() bool {