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fix(identity): guard the DID cache TTLs with its lock, not atomics #191

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Merged
ewanc26 merged 1 commit into from
Oct 7, 2026
Merged

fix(identity): guard the DID cache TTLs with its lock, not atomics #191

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4 changes: 4 additions & 0 deletions CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,10 @@ Everything that changes for someone using Wolfram goes here, newest first, in th

## [Unreleased]

### Fixed

- The DID document cache's TTLs are guarded by its lock rather than atomics. A 64-bit `time_t` has no lock-free atomic load on the 32-bit PowerPC Wii U, so the library failed to link there once a client resolved a DID (Cobalt's sign-in discovery). ([#191](https://github.com/ewanc26/wolfram/pull/191))

## [0.38.1] - 2026-10-07

### Fixed
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23 changes: 13 additions & 10 deletions src/identity/identity.c
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Original file line number Diff line number Diff line change
Expand Up @@ -664,14 +664,17 @@ typedef struct {

static wf_did_cache_entry wf_did_cache[WF_DID_CACHE_SLOTS];
static pthread_mutex_t wf_did_cache_lock = PTHREAD_MUTEX_INITIALIZER;
static _Atomic time_t wf_did_cache_stale_ttl = 3600; /* 1h, matches ref */
static _Atomic time_t wf_did_cache_max_ttl = 86400; /* 1d, matches ref */
/* Guarded by wf_did_cache_lock, not atomics: a 64-bit time_t has no lock-free
* atomic load on 32-bit PowerPC (the Wii U), so __atomic_load_8 does not link.
*/
static time_t wf_did_cache_stale_ttl = 3600; /* 1h, matches ref */
static time_t wf_did_cache_max_ttl = 86400; /* 1d, matches ref */

void wf_did_cache_configure(time_t stale_ttl_seconds, time_t max_ttl_seconds) {
atomic_store_explicit(&wf_did_cache_stale_ttl, stale_ttl_seconds,
memory_order_relaxed);
atomic_store_explicit(&wf_did_cache_max_ttl, max_ttl_seconds,
memory_order_relaxed);
pthread_mutex_lock(&wf_did_cache_lock);
wf_did_cache_stale_ttl = stale_ttl_seconds;
wf_did_cache_max_ttl = max_ttl_seconds;
pthread_mutex_unlock(&wf_did_cache_lock);
}

void wf_did_cache_clear(void) {
Expand Down Expand Up @@ -736,10 +739,10 @@ static void wf_did_cache_put(const char *did, const char *json) {

static wf_status did_fetch_document(wf_xrpc_client *client, const char *did,
cJSON **out_root) {
time_t stale_ttl =
atomic_load_explicit(&wf_did_cache_stale_ttl, memory_order_relaxed);
time_t max_ttl =
atomic_load_explicit(&wf_did_cache_max_ttl, memory_order_relaxed);
pthread_mutex_lock(&wf_did_cache_lock);
time_t stale_ttl = wf_did_cache_stale_ttl;
time_t max_ttl = wf_did_cache_max_ttl;
pthread_mutex_unlock(&wf_did_cache_lock);

if (max_ttl <= 0) return did_fetch_document_uncached(client, did, out_root);

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