Allocate device numbers for VFS2 filesystems.

Updates #1197, #1198, #1672

PiperOrigin-RevId: 310432006

4 files changed, 35 insertions, 19 deletions

diff --git a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
index c7779fc11..1568a9d49 100644
--- a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
+++ b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
@@ -44,11 +44,11 @@ type DynamicBytesFile struct {
 var _ Inode = (*DynamicBytesFile)(nil)
 
 // Init initializes a dynamic bytes file.
-func (f *DynamicBytesFile) Init(creds *auth.Credentials, ino uint64, data vfs.DynamicBytesSource, perm linux.FileMode) {
+func (f *DynamicBytesFile) Init(creds *auth.Credentials, devMajor, devMinor uint32, ino uint64, data vfs.DynamicBytesSource, perm linux.FileMode) {
 	if perm&^linux.PermissionsMask != 0 {
 		panic(fmt.Sprintf("Only permission mask must be set: %x", perm&linux.PermissionsMask))
 	}
-	f.InodeAttrs.Init(creds, ino, linux.ModeRegular|perm)
+	f.InodeAttrs.Init(creds, devMajor, devMinor, ino, linux.ModeRegular|perm)
 	f.data = data
 }
 
diff --git a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
index 615592d5f..982daa2e6 100644
--- a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
+++ b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
@@ -192,15 +192,17 @@ func (InodeNotSymlink) Getlink(context.Context, *vfs.Mount) (vfs.VirtualDentry,
 //
 // Must be initialized by Init prior to first use.
 type InodeAttrs struct {
-	ino   uint64
-	mode  uint32
-	uid   uint32
-	gid   uint32
-	nlink uint32
+	devMajor uint32
+	devMinor uint32
+	ino      uint64
+	mode     uint32
+	uid      uint32
+	gid      uint32
+	nlink    uint32
 }
 
 // Init initializes this InodeAttrs.
-func (a *InodeAttrs) Init(creds *auth.Credentials, ino uint64, mode linux.FileMode) {
+func (a *InodeAttrs) Init(creds *auth.Credentials, devMajor, devMinor uint32, ino uint64, mode linux.FileMode) {
 	if mode.FileType() == 0 {
 		panic(fmt.Sprintf("No file type specified in 'mode' for InodeAttrs.Init(): mode=0%o", mode))
 	}
@@ -209,6 +211,8 @@ func (a *InodeAttrs) Init(creds *auth.Credentials, ino uint64, mode linux.FileMo
 	if mode.FileType() == linux.ModeDirectory {
 		nlink = 2
 	}
+	a.devMajor = devMajor
+	a.devMinor = devMinor
 	atomic.StoreUint64(&a.ino, ino)
 	atomic.StoreUint32(&a.mode, uint32(mode))
 	atomic.StoreUint32(&a.uid, uint32(creds.EffectiveKUID))
@@ -216,6 +220,16 @@ func (a *InodeAttrs) Init(creds *auth.Credentials, ino uint64, mode linux.FileMo
 	atomic.StoreUint32(&a.nlink, nlink)
 }
 
+// DevMajor returns the device major number.
+func (a *InodeAttrs) DevMajor() uint32 {
+	return a.devMajor
+}
+
+// DevMinor returns the device minor number.
+func (a *InodeAttrs) DevMinor() uint32 {
+	return a.devMinor
+}
+
 // Ino returns the inode id.
 func (a *InodeAttrs) Ino() uint64 {
 	return atomic.LoadUint64(&a.ino)
@@ -232,6 +246,8 @@ func (a *InodeAttrs) Mode() linux.FileMode {
 func (a *InodeAttrs) Stat(*vfs.Filesystem, vfs.StatOptions) (linux.Statx, error) {
 	var stat linux.Statx
 	stat.Mask = linux.STATX_TYPE | linux.STATX_MODE | linux.STATX_UID | linux.STATX_GID | linux.STATX_INO | linux.STATX_NLINK
+	stat.DevMajor = a.devMajor
+	stat.DevMinor = a.devMinor
 	stat.Ino = atomic.LoadUint64(&a.ino)
 	stat.Mode = uint16(a.Mode())
 	stat.UID = atomic.LoadUint32(&a.uid)
@@ -544,9 +560,9 @@ type StaticDirectory struct {
 var _ Inode = (*StaticDirectory)(nil)
 
 // NewStaticDir creates a new static directory and returns its dentry.
-func NewStaticDir(creds *auth.Credentials, ino uint64, perm linux.FileMode, children map[string]*Dentry) *Dentry {
+func NewStaticDir(creds *auth.Credentials, devMajor, devMinor uint32, ino uint64, perm linux.FileMode, children map[string]*Dentry) *Dentry {
 	inode := &StaticDirectory{}
-	inode.Init(creds, ino, perm)
+	inode.Init(creds, devMajor, devMinor, ino, perm)
 
 	dentry := &Dentry{}
 	dentry.Init(inode)
@@ -559,11 +575,11 @@ func NewStaticDir(creds *auth.Credentials, ino uint64, perm linux.FileMode, chil
 }
 
 // Init initializes StaticDirectory.
-func (s *StaticDirectory) Init(creds *auth.Credentials, ino uint64, perm linux.FileMode) {
+func (s *StaticDirectory) Init(creds *auth.Credentials, devMajor, devMinor uint32, ino uint64, perm linux.FileMode) {
 	if perm&^linux.PermissionsMask != 0 {
 		panic(fmt.Sprintf("Only permission mask must be set: %x", perm&linux.PermissionsMask))
 	}
-	s.InodeAttrs.Init(creds, ino, linux.ModeDirectory|perm)
+	s.InodeAttrs.Init(creds, devMajor, devMinor, ino, linux.ModeDirectory|perm)
 }
 
 // Open implements kernfs.Inode.
diff --git a/pkg/sentry/fsimpl/kernfs/kernfs_test.go b/pkg/sentry/fsimpl/kernfs/kernfs_test.go
index 1c5d3e7e7..412cf6ac9 100644
--- a/pkg/sentry/fsimpl/kernfs/kernfs_test.go
+++ b/pkg/sentry/fsimpl/kernfs/kernfs_test.go
@@ -75,7 +75,7 @@ type file struct {
 func (fs *filesystem) newFile(creds *auth.Credentials, content string) *kernfs.Dentry {
 	f := &file{}
 	f.content = content
-	f.DynamicBytesFile.Init(creds, fs.NextIno(), f, 0777)
+	f.DynamicBytesFile.Init(creds, 0 /* devMajor */, 0 /* devMinor */, fs.NextIno(), f, 0777)
 
 	d := &kernfs.Dentry{}
 	d.Init(f)
@@ -107,7 +107,7 @@ type readonlyDir struct {
 
 func (fs *filesystem) newReadonlyDir(creds *auth.Credentials, mode linux.FileMode, contents map[string]*kernfs.Dentry) *kernfs.Dentry {
 	dir := &readonlyDir{}
-	dir.attrs.Init(creds, fs.NextIno(), linux.ModeDirectory|mode)
+	dir.attrs.Init(creds, 0 /* devMajor */, 0 /* devMinor */, fs.NextIno(), linux.ModeDirectory|mode)
 	dir.OrderedChildren.Init(kernfs.OrderedChildrenOptions{})
 	dir.dentry.Init(dir)
 
@@ -137,7 +137,7 @@ type dir struct {
 func (fs *filesystem) newDir(creds *auth.Credentials, mode linux.FileMode, contents map[string]*kernfs.Dentry) *kernfs.Dentry {
 	dir := &dir{}
 	dir.fs = fs
-	dir.attrs.Init(creds, fs.NextIno(), linux.ModeDirectory|mode)
+	dir.attrs.Init(creds, 0 /* devMajor */, 0 /* devMinor */, fs.NextIno(), linux.ModeDirectory|mode)
 	dir.OrderedChildren.Init(kernfs.OrderedChildrenOptions{Writable: true})
 	dir.dentry.Init(dir)
 
diff --git a/pkg/sentry/fsimpl/kernfs/symlink.go b/pkg/sentry/fsimpl/kernfs/symlink.go
index 0aa6dc979..2ab3f53fd 100644
--- a/pkg/sentry/fsimpl/kernfs/symlink.go
+++ b/pkg/sentry/fsimpl/kernfs/symlink.go
@@ -35,9 +35,9 @@ type StaticSymlink struct {
 var _ Inode = (*StaticSymlink)(nil)
 
 // NewStaticSymlink creates a new symlink file pointing to 'target'.
-func NewStaticSymlink(creds *auth.Credentials, ino uint64, target string) *Dentry {
+func NewStaticSymlink(creds *auth.Credentials, devMajor, devMinor uint32, ino uint64, target string) *Dentry {
 	inode := &StaticSymlink{}
-	inode.Init(creds, ino, target)
+	inode.Init(creds, devMajor, devMinor, ino, target)
 
 	d := &Dentry{}
 	d.Init(inode)
@@ -45,9 +45,9 @@ func NewStaticSymlink(creds *auth.Credentials, ino uint64, target string) *Dentr
 }
 
 // Init initializes the instance.
-func (s *StaticSymlink) Init(creds *auth.Credentials, ino uint64, target string) {
+func (s *StaticSymlink) Init(creds *auth.Credentials, devMajor uint32, devMinor uint32, ino uint64, target string) {
 	s.target = target
-	s.InodeAttrs.Init(creds, ino, linux.ModeSymlink|0777)
+	s.InodeAttrs.Init(creds, devMajor, devMinor, ino, linux.ModeSymlink|0777)
 }
 
 // Readlink implements Inode.