nss: factorize out nss_{un,}load_module to separate fncs

No change of behavior is intended by this commit.

lib/vtls/nss.c

@@ -207,7 +207,7 @@ static const cipher_s cipherlist[] = {
 };
 
 static const char *pem_library = "libnsspem.so";
-static SECMODModule *mod = NULL;
+static SECMODModule *pem_module = NULL;
 
 /* NSPR I/O layer we use to detect blocking direction during SSL handshake */
 static PRDescIdentity nspr_io_identity = PR_INVALID_IO_LAYER;
@@ -622,7 +622,7 @@ static CURLcode nss_load_key(struct connectdata *conn, int sockindex,
     return CURLE_SSL_CERTPROBLEM;
 
   /* This will force the token to be seen as re-inserted */
-  tmp = SECMOD_WaitForAnyTokenEvent(mod, 0, 0);
+  tmp = SECMOD_WaitForAnyTokenEvent(pem_module, 0, 0);
   if(tmp)
     PK11_FreeSlot(tmp);
   PK11_IsPresent(slot);
@@ -1202,6 +1202,50 @@ static PRStatus nspr_io_close(PRFileDesc *fd)
   return close_fn(fd);
 }
 
+/* load a PKCS #11 module */
+static CURLcode nss_load_module(SECMODModule **pmod, const char *library,
+                                const char *name)
+{
+  char *config_string;
+  SECMODModule *module = *pmod;
+  if(module)
+    /* already loaded */
+    return CURLE_OK;
+
+  config_string = aprintf("library=%s name=%s", library, name);
+  if(!config_string)
+    return CURLE_OUT_OF_MEMORY;
+
+  module = SECMOD_LoadUserModule(config_string, NULL, PR_FALSE);
+  free(config_string);
+
+  if(module && module->loaded) {
+    /* loaded successfully */
+    *pmod = module;
+    return CURLE_OK;
+  }
+
+  if(module)
+    SECMOD_DestroyModule(module);
+  return CURLE_FAILED_INIT;
+}
+
+/* unload a PKCS #11 module */
+static void nss_unload_module(SECMODModule **pmod)
+{
+  SECMODModule *module = *pmod;
+  if(!module)
+    /* not loaded */
+    return;
+
+  if(SECMOD_UnloadUserModule(module) != SECSuccess)
+    /* unload failed */
+    return;
+
+  SECMOD_DestroyModule(module);
+  *pmod = NULL;
+}
+
 /* data might be NULL */
 static CURLcode nss_init_core(struct Curl_easy *data, const char *cert_dir)
 {
@@ -1349,10 +1393,7 @@ void Curl_nss_cleanup(void)
      * the certificates. */
     SSL_ClearSessionCache();
 
-    if(mod && SECSuccess == SECMOD_UnloadUserModule(mod)) {
-      SECMOD_DestroyModule(mod);
-      mod = NULL;
-    }
+    nss_unload_module(&pem_module);
     NSS_ShutdownContext(nss_context);
     nss_context = NULL;
   }
@@ -1707,29 +1748,17 @@ static CURLcode nss_setup_connect(struct connectdata *conn, int sockindex)
     goto error;
   }
 
-  result = CURLE_SSL_CONNECT_ERROR;
-
-  if(!mod) {
-    char *configstring = aprintf("library=%s name=PEM", pem_library);
-    if(!configstring) {
-      PR_Unlock(nss_initlock);
-      goto error;
-    }
-    mod = SECMOD_LoadUserModule(configstring, NULL, PR_FALSE);
-    free(configstring);
-
-    if(!mod || !mod->loaded) {
-      if(mod) {
-        SECMOD_DestroyModule(mod);
-        mod = NULL;
-      }
-      infof(data, "WARNING: failed to load NSS PEM library %s. Using "
-                  "OpenSSL PEM certificates will not work.\n", pem_library);
-    }
-  }
-
   PK11_SetPasswordFunc(nss_get_password);
+
+  result = nss_load_module(&pem_module, pem_library, "PEM");
   PR_Unlock(nss_initlock);
+  if(result == CURLE_FAILED_INIT)
+    infof(data, "WARNING: failed to load NSS PEM library %s. Using "
+                "OpenSSL PEM certificates will not work.\n", pem_library);
+  else if(result)
+    goto error;
+
+  result = CURLE_SSL_CONNECT_ERROR;
 
   model = PR_NewTCPSocket();
   if(!model)