Fix procfs bugs in vfs2.

- Support writing on proc/[pid]/{uid,gid}map
- Return EIO for writing to static files.

Updates #2923.

PiperOrigin-RevId: 318188503

2 files changed, 4 insertions, 2 deletions

diff --git a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
index c1215b70a..6886b0876 100644
--- a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
+++ b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
@@ -101,12 +101,12 @@ func (fd *DynamicBytesFD) Seek(ctx context.Context, offset int64, whence int32)
 	return fd.DynamicBytesFileDescriptionImpl.Seek(ctx, offset, whence)
 }
 
-// Read implmenets vfs.FileDescriptionImpl.Read.
+// Read implements vfs.FileDescriptionImpl.Read.
 func (fd *DynamicBytesFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
 	return fd.DynamicBytesFileDescriptionImpl.Read(ctx, dst, opts)
 }
 
-// PRead implmenets vfs.FileDescriptionImpl.PRead.
+// PRead implements vfs.FileDescriptionImpl.PRead.
 func (fd *DynamicBytesFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
 	return fd.DynamicBytesFileDescriptionImpl.PRead(ctx, dst, offset, opts)
 }
diff --git a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
index 650bd7b88..53aec4918 100644
--- a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
+++ b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
@@ -293,6 +293,8 @@ func (a *InodeAttrs) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *aut
 	// inode numbers are immutable after node creation.
 
 	// TODO(gvisor.dev/issue/1193): Implement other stat fields like timestamps.
+	// Also, STATX_SIZE will need some special handling, because read-only static
+	// files should return EIO for truncate operations.
 
 	return nil
 }