Include context in kernfs.Inode.Stat method

To implement stat(2) in FUSE, we have to embed credentials and pid in request
header. The information should be extracted from the context passed to VFS
layer. Therefore `Stat()` signature in `kernfs.Inode` interface should include
context as first argument. Some other fs implementations need to be modified as
well, such as devpts, host, pipefs, and proc.

Fixes #3235

5 files changed, 8 insertions, 8 deletions

diff --git a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
index 6886b0876..c6c4472e7 100644
--- a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
+++ b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
@@ -127,7 +127,7 @@ func (fd *DynamicBytesFD) Release() {}
 // Stat implements vfs.FileDescriptionImpl.Stat.
 func (fd *DynamicBytesFD) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) {
 	fs := fd.vfsfd.VirtualDentry().Mount().Filesystem()
-	return fd.inode.Stat(fs, opts)
+	return fd.inode.Stat(ctx, fs, opts)
 }
 
 // SetStat implements vfs.FileDescriptionImpl.SetStat.
diff --git a/pkg/sentry/fsimpl/kernfs/fd_impl_util.go b/pkg/sentry/fsimpl/kernfs/fd_impl_util.go
index ca8b8c63b..3f0aea73a 100644
--- a/pkg/sentry/fsimpl/kernfs/fd_impl_util.go
+++ b/pkg/sentry/fsimpl/kernfs/fd_impl_util.go
@@ -132,7 +132,7 @@ func (fd *GenericDirectoryFD) IterDirents(ctx context.Context, cb vfs.IterDirent
 	opts := vfs.StatOptions{Mask: linux.STATX_INO}
 	// Handle ".".
 	if fd.off == 0 {
-		stat, err := fd.inode().Stat(fd.filesystem(), opts)
+		stat, err := fd.inode().Stat(ctx, fd.filesystem(), opts)
 		if err != nil {
 			return err
 		}
@@ -152,7 +152,7 @@ func (fd *GenericDirectoryFD) IterDirents(ctx context.Context, cb vfs.IterDirent
 	if fd.off == 1 {
 		vfsd := fd.vfsfd.VirtualDentry().Dentry()
 		parentInode := genericParentOrSelf(vfsd.Impl().(*Dentry)).inode
-		stat, err := parentInode.Stat(fd.filesystem(), opts)
+		stat, err := parentInode.Stat(ctx, fd.filesystem(), opts)
 		if err != nil {
 			return err
 		}
@@ -176,7 +176,7 @@ func (fd *GenericDirectoryFD) IterDirents(ctx context.Context, cb vfs.IterDirent
 	childIdx := fd.off - 2
 	for it := fd.children.nthLocked(childIdx); it != nil; it = it.Next() {
 		inode := it.Dentry.Impl().(*Dentry).inode
-		stat, err := inode.Stat(fd.filesystem(), opts)
+		stat, err := inode.Stat(ctx, fd.filesystem(), opts)
 		if err != nil {
 			return err
 		}
@@ -226,7 +226,7 @@ func (fd *GenericDirectoryFD) Seek(ctx context.Context, offset int64, whence int
 func (fd *GenericDirectoryFD) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) {
 	fs := fd.filesystem()
 	inode := fd.inode()
-	return inode.Stat(fs, opts)
+	return inode.Stat(ctx, fs, opts)
 }
 
 // SetStat implements vfs.FileDescriptionImpl.SetStat.
diff --git a/pkg/sentry/fsimpl/kernfs/filesystem.go b/pkg/sentry/fsimpl/kernfs/filesystem.go
index 8939871c1..61a36cff9 100644
--- a/pkg/sentry/fsimpl/kernfs/filesystem.go
+++ b/pkg/sentry/fsimpl/kernfs/filesystem.go
@@ -684,7 +684,7 @@ func (fs *Filesystem) StatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf
 	if err != nil {
 		return linux.Statx{}, err
 	}
-	return inode.Stat(fs.VFSFilesystem(), opts)
+	return inode.Stat(ctx, fs.VFSFilesystem(), opts)
 }
 
 // StatFSAt implements vfs.FilesystemImpl.StatFSAt.
diff --git a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
index 4cb885d87..2ab3f1761 100644
--- a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
+++ b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
@@ -243,7 +243,7 @@ func (a *InodeAttrs) Mode() linux.FileMode {
 // Stat partially implements Inode.Stat. Note that this function doesn't provide
 // all the stat fields, and the embedder should consider extending the result
 // with filesystem-specific fields.
-func (a *InodeAttrs) Stat(*vfs.Filesystem, vfs.StatOptions) (linux.Statx, error) {
+func (a *InodeAttrs) Stat(context.Context, *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
diff --git a/pkg/sentry/fsimpl/kernfs/kernfs.go b/pkg/sentry/fsimpl/kernfs/kernfs.go
index 596de1edf..46f207664 100644
--- a/pkg/sentry/fsimpl/kernfs/kernfs.go
+++ b/pkg/sentry/fsimpl/kernfs/kernfs.go
@@ -346,7 +346,7 @@ type inodeMetadata interface {
 
 	// Stat returns the metadata for this inode. This corresponds to
 	// vfs.FilesystemImpl.StatAt.
-	Stat(fs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error)
+	Stat(ctx context.Context, fs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error)
 
 	// SetStat updates the metadata for this inode. This corresponds to
 	// vfs.FilesystemImpl.SetStatAt. Implementations are responsible for checking