Use zend_hrtime instead of time(NULL) since it's monotonic

michael-grunder · michael-grunder · commit dc6e53089af1 · 2025-05-01T10:58:07.000-07:00
`time(NULL)` isn't monotonic and can run backwards so switch to
`zend_hrtime` which uses `clock_gettime(CLOCK_MONOTONIC)` on Linux and
`QueryPerformanceCounter`on Windows.
diff --git a/cluster_library.c b/cluster_library.c
@@ -891,14 +891,18 @@ cluster_free(redisCluster *c, int free_ctx)
     if (free_ctx) efree(c);
 }
 
+static inline uint64_t redis_time(void) {
+    return zend_hrtime() / ZEND_NANO_IN_SEC;
+}
+
 static zend_long cluster_cache_expiry(void) {
     zend_long expiry;
 
     expiry = INI_INT("redis.clusters.slot_cache_expiry");
     if (expiry <= 0)
         return 0;
 
-    return time(NULL) + expiry;
+    return redis_time() + expiry;
 }
 
 #ifdef HAVE_REDIS_ATOMICS_MMAP
@@ -3172,7 +3176,7 @@ PHP_REDIS_API redisCachedCluster *cluster_cache_load(zend_string *hash) {
 
     cc = le->ptr;
     /* Short circuit if it should be expired */
-    if (cc->expiry != 0 && cc->expiry <= time(NULL))
+    if (cc->expiry != 0 && cc->expiry <= redis_time())
         return NULL;
 
 #ifdef HAVE_REDIS_ATOMICS_MMAP
