mailbox_client: filter GetBuiltins return

The addition of build artifacts to the tarball causes the GetBuiltins
return list to overflow. Add a temporary hack to filter out known build
artifacts (may be better to selectively include instead).

Change-Id: Ife1901859e8b710cd9d243f0a1e3b291a4a0390a

app/src/mailbox_client.rs

diff --git a/app/src/mailbox_client.rs b/app/src/mailbox_client.rs
index 3993ab2..671542f 100644
--- a/app/src/mailbox_client.rs
+++ b/app/src/mailbox_client.rs
@@ -207,12 +207,16 @@
             let (status, name_len, next_fid) = get_name_result.into_inner();
             if !status.unwrap() { break; }
             if let Ok(str) = core::str::from_utf8(&name[..name_len]) {
-                // XXX filter non-builtins? (harder if capdl-loader cpio archive is expanded)
+                // XXX maybe explicitly include instead of filtering out?
                 match str {
-                    "kernel" |
-                    "capdl-loader" |
-                    "matcha-tock-bundle.bin" => {}
-                    _ => names.push(str.to_string()),
+                    // Filter bootstrap artifacts.
+                    "kernel" | "capdl-loader" | "matcha-tock-bundle.bin" => {}
+                    _ => {
+                        // Filter CAmkES component executables.
+                        if !str.ends_with("_group_bin") {
+                            names.push(str.to_string());
+                        }
+                    }
                 }
             }
             fid = next_fid as u32;