client: libuv: fix close handling during redirect

During client redirect we "reset" the wsi to the redirect address,
involving closing the current fd that was told to redirect (it will
usually be a completely different server or port).

With libuv and its two-stage close that's not trivial.  This solves
the problem we will "reset" (overwrite) where the handle lives in the
wsi with new a new connection / handle by having it copied out into
an allocated watcher struct, which is freed in the uv close callback.

To confirm it the minimal ws client example gets some new options, the
original problem was replicated with this

$ lws-minimal-ws-client-echo -s invalid.url.com -p 80

https://github.com/warmcat/libwebsockets/issues/1390

lib/core/context.c

@@ -134,7 +134,7 @@ lws_protocol_vh_priv_get(struct lws_vhost *vhost,
 {
 	int n = 0;
 
-	if (!vhost || !vhost->protocol_vh_privs)
+	if (!vhost || !vhost->protocol_vh_privs || !prot)
 		return NULL;
 
 	while (n < vhost->count_protocols && &vhost->protocols[n] != prot)

lib/event-libs/libuv/libuv.c

@@ -317,6 +317,7 @@ lws_libuv_closewsi_m(uv_handle_t* handle)
 	lws_sockfd_type sockfd = (lws_sockfd_type)(lws_intptr_t)handle->data;
 
 	compatible_close(sockfd);
+	lws_free(handle);
 }
 
 int
@@ -593,12 +594,15 @@ elops_check_client_connect_ok_uv(struct lws *wsi)
 static void
 elops_close_handle_manually_uv(struct lws *wsi)
 {
-	uv_handle_t *h = (void *)&wsi->w_read.uv.watcher;
+	struct lws_io_watcher *h = (void *)&wsi->w_read.uv.watcher, *nh;
+
+	nh = lws_malloc(sizeof(*h), __func__);
+	*nh = *h;
 
 	lwsl_debug("%s: lws_libuv_closehandle: wsi %p\n", __func__, wsi);
-	h->data = (void *)(lws_intptr_t)wsi->desc.sockfd;
+	((uv_handle_t *)nh)->data = (void *)(lws_intptr_t)wsi->desc.sockfd;
 	/* required to defer actual deletion until libuv has processed it */
-	uv_close((uv_handle_t*)&wsi->w_read.uv.watcher, lws_libuv_closewsi_m);
+	uv_close((uv_handle_t *)nh, lws_libuv_closewsi_m);
 }
 
 static void

lib/roles/http/client/client-handshake.c

@@ -654,13 +654,13 @@ lws_client_reset(struct lws **pwsi, int ssl, const char *address, int port,
 	lws_ssl_close(wsi);
 #endif
 
+	__remove_wsi_socket_from_fds(wsi);
+
 	if (wsi->context->event_loop_ops->close_handle_manually)
 		wsi->context->event_loop_ops->close_handle_manually(wsi);
 	else
 		compatible_close(wsi->desc.sockfd);
 
-	__remove_wsi_socket_from_fds(wsi);
-
 #if defined(LWS_WITH_TLS)
 	wsi->tls.use_ssl = ssl;
 #else

minimal-examples/ws-client/minimal-ws-client-echo/minimal-ws-client-echo.c

@@ -22,6 +22,7 @@ static struct lws_protocols protocols[] = {
 	{ NULL, NULL, 0, 0 } /* terminator */
 };
 
+static struct lws_context *context;
 static int interrupted, port = 7681, options = 0;
 static const char *url = "/", *ads = "localhost";
 
@@ -87,9 +88,8 @@ void sigint_handler(int sig)
 int main(int argc, const char **argv)
 {
 	struct lws_context_creation_info info;
-	struct lws_context *context;
 	const char *p;
-	int n = 0, logs = LLL_USER | LLL_ERR | LLL_WARN | LLL_NOTICE
+	int logs = LLL_USER | LLL_ERR | LLL_WARN | LLL_NOTICE
 			/* for LLL_ verbosity above NOTICE to be built into lws,
 			 * lws must have been configured and built with
 			 * -DCMAKE_BUILD_TYPE=DEBUG instead of =RELEASE */
@@ -97,8 +97,6 @@ int main(int argc, const char **argv)
 			/* | LLL_EXT */ /* | LLL_CLIENT */ /* | LLL_LATENCY */
 			/* | LLL_DEBUG */;
 
-	signal(SIGINT, sigint_handler);
-
 	if ((p = lws_cmdline_option(argc, argv, "-d")))
 		logs = atoi(p);
 
@@ -115,7 +113,10 @@ int main(int argc, const char **argv)
 	if (lws_cmdline_option(argc, argv, "-o"))
 		options |= 1;
 
-	lwsl_user("options %d\n", options);
+	if ((p = lws_cmdline_option(argc, argv, "-s")))
+		ads = p;
+
+	lwsl_user("options %d, ads %s\n", options, ads);
 
 	memset(&info, 0, sizeof info); /* otherwise uninitialized garbage */
 	info.port = CONTEXT_PORT_NO_LISTEN;
@@ -124,7 +125,13 @@ int main(int argc, const char **argv)
 	if (!lws_cmdline_option(argc, argv, "-n"))
 		info.extensions = extensions;
 	info.pt_serv_buf_size = 32 * 1024;
-	info.options = LWS_SERVER_OPTION_VALIDATE_UTF8;
+	info.options = LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT |
+		       LWS_SERVER_OPTION_VALIDATE_UTF8;
+
+	if (lws_cmdline_option(argc, argv, "--libuv"))
+		info.options |= LWS_SERVER_OPTION_LIBUV;
+	else
+		signal(SIGINT, sigint_handler);
 
 	context = lws_create_context(&info);
 	if (!context) {
@@ -132,8 +139,8 @@ int main(int argc, const char **argv)
 		return 1;
 	}
 
-	while (n >= 0 && !interrupted)
-		n = lws_service(context, 1000);
+	while (!lws_service(context, 1000) && !interrupted)
+		;
 
 	lws_context_destroy(context);