theiphoneos1project/iphoneos1-sdk

Purpose and Entry Point

This repository generates a compatibility SDK for targeting iPhone OS 1. It assembles user-supplied Mac OS X 10.5 and iPhone OS 2 SDK material with repository-provided overrides, linker shims, and runtime startup support. The operational entry point is generate.py; it accepts source SDK paths plus include, shim_sdk, and csu inputs.

Generation Orchestrator

generate.py is the control-plane script: it receives SDK locations and an output path, then constructs the generated SDK from multiple source boundaries. The repository does not contain an application or device-side service; its main product is a filesystem SDK layout for downstream compilers/linkers.

• generate.py

• README.md

Header Reconstruction Layer

The checked-in include/ tree supplies manually written or reverse-engineered compatibility headers and local API declarations that complement copied upstream headers. It spans public and private iPhone-era frameworks, making this the primary compile-time API surface.

• include/UIKit/UIKit.h

• include/Message/Message.h

• include/Celestial/Celestial.h

Platform and ABI Surface

Low-level C, ARM, Mach, and system declarations establish the target ABI expected by old iPhone OS binaries. This is a boundary between source compatibility and the ARM/device execution environment.

• include/architecture/arm/

• include/mach/arm/

• include/arm/_types.h

Link-Time Framework Shim SDK

shim_sdk/ mirrors /System/Library/Frameworks and private-framework locations using .tbd linker-interface files rather than Apple binaries. The generated SDK uses these interfaces to resolve framework linkage while actual implementations remain on the target device.

• shim_sdk/System/Library/Frameworks/UIKit.framework/UIKit.tbd

• shim_sdk/System/Library/Frameworks/Foundation.framework/Foundation.tbd

• shim_sdk/System/Library/PrivateFrameworks/vmutils.framework/vmutils.tbd

Runtime Startup Support

The csu/ directory provides ARM C runtime/startup artifacts required for produced binaries to start correctly on-device, including assembly entry glue and CRT objects. This is the execution-time boundary between linked app code and the platform dynamic loader/runtime.

• csu/arm-start.s

• csu/arm-dyld-glue.s

• csu/crt.c

Primary Flow and External Dependencies

1. A user provides legally obtained Mac OS X 10.5 and iPhone OS 2 SDK directories.

2. generate.py combines selected upstream headers with include/ overrides/compatibility declarations.

3. It incorporates shim_sdk/ framework interfaces for linker resolution and csu/ runtime files for binary startup.

4. The resulting SDK is consumed by an ARM/iPhone OS toolchain; linked applications depend at runtime on frameworks supplied by an iPhone OS 1 device.

Material external dependencies are Python 3, the two user-provided SDKs, an ARM-capable compiler/linker toolchain, and device-resident Apple frameworks. The repository itself intentionally avoids distributing Apple SDK binaries.