From b4820e598681c61fbf0e8a7f4d3436d2599ce53c Mon Sep 17 00:00:00 2001
From: Rahat Mahmood <rahat@google.com>
Date: Fri, 28 Aug 2020 14:29:16 -0700
Subject: Implement StatFS for various VFS2 filesystems.

This mainly involved enabling kernfs' client filesystems to provide a
StatFS implementation.

Fixes #3411, #3515.

PiperOrigin-RevId: 329009864
---
 pkg/sentry/fsimpl/devpts/devpts.go | 10 +++++++++-
 pkg/sentry/fsimpl/devpts/master.go |  1 +
 pkg/sentry/fsimpl/devpts/slave.go  |  1 +
 3 files changed, 11 insertions(+), 1 deletion(-)

(limited to 'pkg/sentry/fsimpl/devpts')

diff --git a/pkg/sentry/fsimpl/devpts/devpts.go b/pkg/sentry/fsimpl/devpts/devpts.go
index 0eaff9087..57580f4d4 100644
--- a/pkg/sentry/fsimpl/devpts/devpts.go
+++ b/pkg/sentry/fsimpl/devpts/devpts.go
@@ -111,12 +111,13 @@ func (fs *filesystem) Release(ctx context.Context) {
 
 // rootInode is the root directory inode for the devpts mounts.
 type rootInode struct {
-	rootInodeRefs
+	implStatFS
 	kernfs.AlwaysValid
 	kernfs.InodeAttrs
 	kernfs.InodeDirectoryNoNewChildren
 	kernfs.InodeNotSymlink
 	kernfs.OrderedChildren
+	rootInodeRefs
 
 	locks vfs.FileLocks
 
@@ -240,3 +241,10 @@ func (i *rootInode) IterDirents(ctx context.Context, cb vfs.IterDirentsCallback,
 func (i *rootInode) DecRef(context.Context) {
 	i.rootInodeRefs.DecRef(i.Destroy)
 }
+
+type implStatFS struct{}
+
+// StatFS implements kernfs.Inode.StatFS.
+func (*implStatFS) StatFS(context.Context, *vfs.Filesystem) (linux.Statfs, error) {
+	return vfs.GenericStatFS(linux.DEVPTS_SUPER_MAGIC), nil
+}
diff --git a/pkg/sentry/fsimpl/devpts/master.go b/pkg/sentry/fsimpl/devpts/master.go
index 3bb397f71..60feb1993 100644
--- a/pkg/sentry/fsimpl/devpts/master.go
+++ b/pkg/sentry/fsimpl/devpts/master.go
@@ -30,6 +30,7 @@ import (
 
 // masterInode is the inode for the master end of the Terminal.
 type masterInode struct {
+	implStatFS
 	kernfs.InodeAttrs
 	kernfs.InodeNoopRefCount
 	kernfs.InodeNotDirectory
diff --git a/pkg/sentry/fsimpl/devpts/slave.go b/pkg/sentry/fsimpl/devpts/slave.go
index 32e4e1908..a9da7af64 100644
--- a/pkg/sentry/fsimpl/devpts/slave.go
+++ b/pkg/sentry/fsimpl/devpts/slave.go
@@ -29,6 +29,7 @@ import (
 
 // slaveInode is the inode for the slave end of the Terminal.
 type slaveInode struct {
+	implStatFS
 	kernfs.InodeAttrs
 	kernfs.InodeNoopRefCount
 	kernfs.InodeNotDirectory
-- 
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