D295 - Dynamic module resolution for non-essential libraries

Status: [decided] Date: 2026-09-02 Context: Investigating native PS5 title launch aborts where processes exit before entry point execution.

Context

On PlayStation 5 (Prospero), the system dynamic linker (rtld / self_load_shared_object) inspects all DT_SCE_NEEDED / DT_NEEDED entries declared in an executable's dynamic section during process creation. This module resolution takes place before jumping to the process entry point (obscene_start) or running DT_INIT.

If even a single library in DT_NEEDED fails to resolve on disk, rtld aborts process initialization with val 2 (ENOENT). The process terminates immediately without executing a single instruction, preventing any diagnostics, logs, or reports from being emitted.

Inspection of /system/common/lib/ on retail PS5 firmware revealed that certain libraries commonly present on PS4 or assumed by the probe—specifically libScePosix.sprx and libSceVencCore.sprx—do not exist in the standard PS5 application library path (their equivalents exist in other locations, such as /system_ex/common_ex/lib/libScePosixForWebKit.sprx and /system/common/lib/libSceVenc.sprx). Linking them statically forced DT_NEEDED entries that caused immediate launch aborts for native titles.

Decision

  1. Remove non-essential modules from static platform imports:
    • libScePosix and libSceVencCore are removed from src/probe/imports.c.
    • symbols-no-census.txt generated for eboot builds contains only the 12 core libraries confirmed to exist in /system/common/lib/.
  2. Pivot non-essential library checks to dynamic runtime resolution:
    • Sections such as 017-posix and 106-encoder resolve their target functions dynamically via obs_module_open() and obs_module_symbol().
    • If a library or symbol cannot be resolved within the process's current sandbox, the check records an honest obs_skip("libScePosix is not available in current sandbox") instead of halting the loader.
  3. Preserve host build verification:
    • The host test harness (OBSCENE_HOST_BUILD) retains local libc implementations for verification in CI without requiring the console libraries.

Consequences