# Investigate ELF packaging without an external linker

Type: research
Status: resolved
Parent: [Find the ASPL MVP specification](../map.md)

## Question

Which documented x86-64 glibc ELF mechanisms can a C11 ASPL tool use to emit a runnable native program containing a prebuilt register VM and program bytecode without invoking a compiler, assembler, or linker, and what constraints would each feasible mechanism place on dynamic dependencies, bytecode placement, process startup, and executable integrity?

## Answer

Use a release-built x86-64 PIE VM template with a dedicated final read-only `PT_LOAD` segment. `aspl build` copies the embedded template, writes a versioned bytecode envelope into that segment, and patches only its file and memory sizes. The existing glibc startup path and fixed VM dependencies remain intact; program-specific shared libraries load at runtime through `dlopen` and `dlsym`. A self-reading file overlay is feasible but depends on procfs and startup file I/O, while rewriting dynamic ELF metadata would amount to implementing a linker. The emitter must validate the template and all ELF bounds, publish outputs atomically, and validate a payload integrity value before execution.

Full findings and primary-source citations: [ELF packaging without an external linker](../research/01-elf-packaging.md)