From e721d09f8a21af62b613cc1da30e1abc8e3554d8 Mon Sep 17 00:00:00 2001
From: Lutz Reinhardt <lutz.reinhardt@elektrobit.com>
Date: Fri, 28 Aug 2026 16:44:56 +0200
Subject: [PATCH] feat: Script for making the SDK self contained

At ELF files interpreter and libc have to be compatible.
This is achieved by either calling `relocate-sdk.sh`,
which sets the interpreter, using the host interpreter and
libc or wrapping all executables so that the interpreter
from the SDK is used.

This wraps the executables so that the SDK is usable
without extra setup steps.
---
 scripts/make-self-contained.sh | 93 ++++++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)
 create mode 100755 scripts/make-self-contained.sh

diff --git a/scripts/make-self-contained.sh b/scripts/make-self-contained.sh
new file mode 100755
index 0000000..64bb101
--- /dev/null
+++ b/scripts/make-self-contained.sh
@@ -0,0 +1,93 @@
+#!/usr/bin/env bash
+# Copyright 2026 Elektrobit. All rights reserved.
+#
+# Makes an SDK tree relocatable without patching any ELF headers.
+#
+# For every host executable shipped by the SDK (the same set of directories
+# `relocate-sdk.sh` / the ebclfsa `patch_cmds` operate on), this script:
+#   1. renames "$binary" to "$binary.real"
+#   2. drops a small shell wrapper at "$binary" that explicitly invokes the
+#      SDK's own loader (ld-linux) with an explicit --library-path, so the
+#      binary works no matter where the SDK tree is unpacked, without ever
+#      rewriting the ELF interpreter/rpath of "$binary.real".
+#
+# This is idempotent: binaries that are already wrappers (plain text, not
+# ELF) are skipped, so running the script twice on the same tree is a no-op
+# the second time.
+set -euo pipefail
+
+usage() {
+    echo "Usage: $0 <sdk-root>" >&2
+    exit 1
+}
+
+[ $# -eq 1 ] || usage
+
+sdk_root=$(cd "$1" && pwd)
+arch=$(uname -m)
+
+loader="$sdk_root/usr/lib/$arch-linux-gnu/ld-linux-x86-64.so.2"
+if [ ! -x "$loader" ]; then
+    echo "error: SDK loader not found at $loader" >&2
+    exit 1
+fi
+
+# Same search roots as relocate-sdk.sh / _EBCLFSA_RELOCATE_CMDS, filtered to
+# the ones that actually exist so an unmatched glob doesn't reach `find`.
+search_dirs=()
+for pattern in "$sdk_root"/usr/bin "$sdk_root"/usr/sbin \
+    "$sdk_root"/usr/lib/gcc* "$sdk_root"/usr/libexec/gcc* \
+    "$sdk_root"/usr/lib/llvm*/bin; do
+    [ -d "$pattern" ] && search_dirs+=("$pattern")
+done
+
+is_elf() {
+    local magic
+    magic=$(head -c4 "$1" 2>/dev/null | od -An -tx1 | tr -d ' \n')
+    [ "$magic" = "7f454c46" ]
+}
+
+count=0
+# Snapshot the file list up front: renaming files while `find` is still
+# walking the tree would let it re-discover freshly created "*.real" files
+# as if they were new binaries, and wrap them a second time.
+mapfile -d '' -t binaries < <(find "${search_dirs[@]}" -type f -perm -u+x -print0 2>/dev/null)
+for binary in "${binaries[@]}"; do
+    # A ".real" binary is the already-renamed original from a previous run;
+    # never re-wrap it (that would shadow it behind a second wrapper).
+    case "$binary" in
+    *.real) continue ;;
+    esac
+
+    # Shared libraries can be executable files too, but must remain ELF
+    # libraries because tools such as GCC load them directly as plugins.
+    case "$(basename "$binary")" in
+    *.so|*.so.*) continue ;;
+    esac
+    is_elf "$binary" || continue
+
+    dir=$(dirname "$binary")
+    name=$(basename "$binary")
+    real="$dir/$name.real"
+
+    [ -e "$real" ] && continue
+
+    # Relative path from the wrapper's own directory back to sdk_root, so the
+    # wrapper keeps working wherever the whole tree gets moved/extracted to.
+    rel_to_root=$(realpath --relative-to="$dir" "$sdk_root")
+
+    mv "$binary" "$real"
+    cat >"$binary" <<EOF
+#!/bin/sh
+here=\$(dirname "\$(readlink -f "\$0")")
+sdk=\$here/$rel_to_root
+exec "\$sdk/usr/lib/$arch-linux-gnu/ld-linux-x86-64.so.2" \\
+    --argv0 "\$0" \\
+    --library-path "\$sdk/usr/lib/$arch-linux-gnu:\$sdk/lib/$arch-linux-gnu" \\
+    "\$here/$name.real" "\$@"
+EOF
+    chmod +x "$binary"
+    count=$((count + 1))
+done
+
+echo "wrapped $count binaries under $sdk_root"