Crate embala_setup_overlay 

Fixed-size PE-overlay trailer (spec R5).

setup.exe is [stub][payload.zip][install.lua][uninstall.lua][manifest][signed_stub] followed by (optional alignment padding and) this fixed-size trailer. The runtime locates the trailer at overlay_end − TRAILER_LEN — the overlay end being the raw EOF for an unsigned file but the Authenticode certificate-table offset once signed (see pe::overlay_end) — reads these bytes, validates MAGIC, and then locates every other section from the offset/length table.

Byte layout (little-endian, TRAILER_LEN = 108 bytes):

offset  size  field
  0       8   magic                = b"EMBALASU"
  8       4   format version (u32) = FORMAT_VERSION
 12    6×16   section table: (offset u64, len u64) for
              stub, payload.zip, install.lua, uninstall.lua, manifest,
              signed_stub (zero-length = none embedded)

This is the single source of truth shared by both sides of the overlay: the package-time writer (embala-setup, which Trailer::to_bytes) and the install-time runtime (embala-setup-runtime, which Trailer::parse). It is its own crate — with no dependency on the stubs — so the two never form a cycle (the runtime cannot depend on embala-setup, which include_bytes!s the runtime).

Modules

pe

Locate the overlay end relative to the PE, not the raw file EOF.

Structs

Manifest

The manifest embedded in the overlay’s manifest section.

Package

Product identity, mirrored from the embala [package] section.

Section

A byte range of one overlay section within the setup.exe file.

Trailer

Parsed overlay trailer. stub.len is the overlay start (spec R5); the uninstaller copies [0..stub.len) as its engine prefix (Phase 3).

UninstallOption

One declarative uninstall option (spec R2). default pre-ticks its checkbox.

Enums

TrailerError

Why a trailer failed to parse.

Constants

FORMAT_VERSION

Overlay format version. Bumped on any incompatible layout change.

MAGIC

Trailer magic: “EMBALA SetUp”.

SECTION_COUNT

Sections described by the table, in serialized order.

TRAILER_LEN

Total trailer size: magic (8) + version (4) + 6 × (offset u64 + len u64).