wolfcrypt/src/wc_port.c:

* fixes for readability-implicit-bool-conversion in wolfSSL_Atomic_Ptr_CompareExchange().
* refactor initRefCount as a wolfSSL_Atomic_Int, unless !WOLFSSL_ATOMIC_OPS, for thread safety.

Author: douzzer

wolfcrypt/src/wc_port.c

@@ -151,7 +151,11 @@
 #endif
 
 /* prevent multiple mutex initializations */
-static volatile int initRefCount = 0;
+#ifdef WOLFSSL_ATOMIC_OPS
+    wolfSSL_Atomic_Int initRefCount = WOLFSSL_ATOMIC_INITIALIZER(0);
+#else
+    static int initRefCount = 0;
+#endif
 
 #if defined(__aarch64__) && defined(WOLFSSL_ARMASM_BARRIER_DETECT)
 int aarch64_use_sb = 0;
@@ -164,7 +168,8 @@ WOLFSSL_ABI
 int wolfCrypt_Init(void)
 {
     int ret = 0;
-    if (initRefCount == 0) {
+    int my_initRefCount = wolfSSL_Atomic_Int_FetchAdd(&initRefCount, 1);
+    if (my_initRefCount == 0) {
         WOLFSSL_ENTER("wolfCrypt_Init");
 
     #if defined(__aarch64__) && defined(WOLFSSL_ARMASM_BARRIER_DETECT)
@@ -444,8 +449,16 @@ int wolfCrypt_Init(void)
             return ret;
         }
 #endif
+
+        /* increment to 2, to signify successful initialization: */
+        (void)wolfSSL_Atomic_Int_FetchAdd(&initRefCount, 1);
+    }
+    else {
+        if (my_initRefCount < 2) {
+            (void)wolfSSL_Atomic_Int_FetchSub(&initRefCount, 1);
+            ret = BUSY_E;
+        }
     }
-    initRefCount++;
 
     return ret;
 }
@@ -469,12 +482,9 @@ WOLFSSL_ABI
 int wolfCrypt_Cleanup(void)
 {
     int ret = 0;
+    int my_initRefCount = wolfSSL_Atomic_Int_SubFetch(&initRefCount, 1);
 
-    initRefCount--;
-    if (initRefCount < 0)
-        initRefCount = 0;
-
-    if (initRefCount == 0) {
+    if (my_initRefCount == 1) {
         WOLFSSL_ENTER("wolfCrypt_Cleanup");
 
 #ifdef HAVE_ECC
@@ -564,6 +574,8 @@ int wolfCrypt_Cleanup(void)
          * must be freed. */
         wc_MemZero_Free();
     #endif
+
+        (void)wolfSSL_Atomic_Int_SubFetch(&initRefCount, 1);
     }
 
 #if defined(HAVE_LIBOQS)
@@ -1462,9 +1474,17 @@ int wolfSSL_Atomic_Ptr_CompareExchange(
      * atomic_compare_exchange_strong_explicit(), to sidestep _Atomic type
      * requirements.
      */
-    return __atomic_compare_exchange_n(
-        c, expected_ptr, new_ptr, 0 /* weak */,
-        __ATOMIC_SEQ_CST, __ATOMIC_ACQUIRE);
+     if (__atomic_compare_exchange_n(
+             c, expected_ptr, new_ptr,
+#ifdef WOLF_C89
+             0 /* weak */,
+#else
+             (_Bool)0 /* weak */,
+#endif
+             __ATOMIC_SEQ_CST, __ATOMIC_ACQUIRE))
+         return 1;
+     else
+         return 0;
 }
 
 #elif defined(__GNUC__) && defined(__ATOMIC_RELAXED)