Complete evidence-backed semaphore and pthread utility surface

[millesant]

Status: Verification

Parent: #37
Depends on: #38 and #41 (both satisfied).

Goal

Fill gaps in the common pthread/semaphore utility surface only where supplied ARM32 libraries or integration evidence require them, without turning the project into a blanket POSIX implementation.

Candidate APIs

Prioritize by observed imports/machine code before implementation:

• sem_trywait, sem_getvalue, sem_timedwait;
• mutex timed lock;
• additional pthread attr getters/setters;
• pthread_getattr_np-style queries if proven;
• thread naming/scheduling helpers only if libraries require them.

Rules

• Reuse existing semaphore/mutex/logical-thread state.
• Timed functions use the accepted clock/deadline seam.
• Query APIs return synthetic logical state, not host pthread internals.
• Unsupported scheduling knobs may return verified Android errors rather than silently faking success when that is semantically safer.
• Each added symbol must have evidence and bounded failure behavior.

Acceptance criteria

• Maintain an evidence table in the issue/architecture docs mapping each implemented symbol to supplied binary or reproducible fixture evidence.
• No duplicate synchronization state models.
• Exact Android return/error behavior is documented for accepted calls.
• Partial libc shim exports increase only for accepted symbols.
• Existing 45-export pthread/libc fixture remains backward compatible.

Validation

Focused tests per accepted API, real ARM32 relocation/wrapper integration, and exact-head CI.

Evidence — supplied artifacts (2026-10-02)

• ARM32 FMOD libfmod.so (sha256 982e994c46a7f797fbd6e10df31a98d544c2bf117fe33c2292f4d6cc454a6544) adds no utility imports beyond the already accepted lifecycle/mutex surface.
• VLC APK VLC-Android-3.7.2-Beta-2-all-20260925-0117.apk (sha256 10da537a545d5c9aa111571bbab3d1aae4204d2c4a0d4a4cdc22efab6d71cbe5), scanning every lib/armeabi-v7a/*.so, finds new utility imports only in ARM32 libvlc.so: pthread_attr_getstacksize (already implemented), pthread_setname_np, pthread_setschedparam, and pthread_getschedparam.
• Supplied libemu32.so is AArch64, not AArch32 (sha256 a467c34bc1543a2a193191ad42c4ac3a8e4a00181e83fa223abf7d42bc421119). Its sem_trywait, sem_getvalue, and pthread_attr_setschedparam imports do not justify expanding the AArch32 shim.
• No supplied ARM32 artifact evidence was found for sem_trywait, sem_getvalue, sem_timedwait, pthread_mutex_timedlock, pthread_attr_setschedparam, or pthread_getattr_np; keep those out of this implementation slice.

Non-goals

Implementing every pthread/sem extension merely because Bionic exports it.

[millesant]

Branch: issue-43-pthread-utility-surface
Commit: cff741b
Implemented: evidence-backed ARM32 pthread_getschedparam, pthread_setschedparam, and pthread_setname_np on existing bounded logical lifecycle state; partial libc shim + ARM32 consumer/integration extended to 35 imports; focused scheduler/name regressions; workflow evidence gates and durable contracts/architecture/evidence updated. Corrected supplied libemu32.so evidence to AArch64 and kept semaphore/attr-scheduling candidates out of the AArch32 slice.
Validation: PENDING — exact-head PR #58 snapshot for cff741b has Repository hygiene PASS; CI, Public C embedding API, ARM32 JNI registration bootstrap, ARM32 libdl shim, ARM32 libm shim, ARM32 libc memory string shim, ARM32 liblog shim, and ARM32 Android app library search are running.
Manual: NOT RUN
Remaining: CI: PENDING. On next check, inspect this exact SHA once; if green, merge PR #58 and close #43. If a workflow fails, inspect only the relevant failed job/step.

[millesant]

Branch: issue-43-pthread-utility-surface
Commit: cff741b
Implemented: evidence-backed ARM32 pthread_getschedparam, pthread_setschedparam, and pthread_setname_np with bounded logical scheduler/name state; ARM32 shim/integration, focused tests, workflow evidence gates, contracts, architecture, and binary evidence updated.
Validation: PASS — all nine exact-head PR #58 workflows succeeded for cff741b.
Manual: NOT RUN
Findings: supplied libemu32.so is AArch64, so its semaphore/attr-scheduling imports were not used to broaden the AArch32 surface.
Merge: ed9fdcf