lwsws conf and plugins convert to libuv apis

After discussion here

https://libwebsockets.org/pipermail/libwebsockets/2016-April/002268.html

scandir usage in

 - lwsws conf.c
 - lws plugin support

and

 - lws plugin apis for dl

are converted to us libuv apis so they can work cross-platform easily.

lws itself remains not requiring libuv, although it's an option.

 - LWS_WITH_LWSWS
 - LWS_WITH_PLUGINS

now force LWS_WITH_LIBUV if selected... both of these are new features
only in master atm and both are off by default in CMake.

There's a complication libuv can be too old to offer the necessary apis,
this is the case in Travis Trusty instance.  In that case, UV_VERSION_MAJOR ==0,
then the unix-only plugin implementation is used instead.

Signed-off-by: Andy Green <andy@warmcat.com>

CMakeLists.txt

@@ -100,6 +100,11 @@ if (LWS_WITH_LWSWS)
  set(LWS_WITH_LIBUV 1)
 endif()
 
+if (LWS_WITH_PLUGINS AND NOT LWS_WITH_LIBUV)
+message(STATUS "LWS_WITH_PLUGINS --> Enabling LWS_WITH_LIBUV")
+ set(LWS_WITH_LIBUV 1)
+endif()
+
 if (DEFINED YOTTA_WEBSOCKETS_VERSION_STRING)
 
 set(LWS_WITH_SHARED OFF)
@@ -118,9 +123,6 @@ endif()
 if (WIN32)
 # this implies no pthreads in the lib
 set(LWS_MAX_SMP 1)
-
-# plugin stuff not implemented in win32 plat
-set (LWS_WITH_PLUGINS OFF)
 endif()
 
 

lib/libuv.c

@@ -408,3 +408,134 @@ lws_libuv_closehandle(struct lws *wsi)
 	if (context->requested_kill && context->count_wsi_allocated == 0)
 		lws_libuv_kill(context);
 }
+
+#if defined(LWS_WITH_PLUGINS) && (UV_VERSION_MAJOR > 0)
+
+LWS_VISIBLE int
+lws_plat_plugins_init(struct lws_context * context, const char *d)
+{
+	struct lws_plugin_capability lcaps;
+	struct lws_plugin *plugin;
+	lws_plugin_init_func initfunc;
+	int m, ret = 0;
+	void *v;
+	uv_dirent_t dent;
+	uv_fs_t req;
+	char path[256];
+	uv_loop_t loop;
+	uv_lib_t lib;
+
+	lib.errmsg = NULL;
+	lib.handle = NULL;
+
+	uv_loop_init(&loop);
+
+	if (!uv_fs_scandir(&loop, &req, d, 0, NULL)) {
+		lwsl_err("Scandir on %s failed\n", d);
+		return 1;
+	}
+
+	lwsl_notice("  Plugins:\n");
+
+	while (uv_fs_scandir_next(&req, &dent) != UV_EOF) {
+		if (strlen(dent.name) < 7)
+			continue;
+
+		lwsl_notice("   %s\n", dent.name);
+
+		snprintf(path, sizeof(path) - 1, "%s/%s", d, dent.name);
+		if (uv_dlopen(path, &lib)) {
+			uv_dlerror(&lib);
+			lwsl_err("Error loading DSO: %s\n", lib.errmsg);
+			goto bail;
+		}
+		/* we could open it, can we get his init function? */
+		m = snprintf(path, sizeof(path) - 1, "init_%s",
+			     dent.name + 3 /* snip lib... */);
+		path[m - 3] = '\0'; /* snip the .so */
+		if (uv_dlsym(&lib, path, &v)) {
+			uv_dlerror(&lib);
+			lwsl_err("Failed to get init on %s: %s",
+					dent.name, lib.errmsg);
+			goto bail;
+		}
+		initfunc = (lws_plugin_init_func)v;
+		lcaps.api_magic = LWS_PLUGIN_API_MAGIC;
+		m = initfunc(context, &lcaps);
+		if (m) {
+			lwsl_err("Initializing %s failed %d\n", dent.name, m);
+			goto skip;
+		}
+
+		plugin = lws_malloc(sizeof(*plugin));
+		if (!plugin) {
+			lwsl_err("OOM\n");
+			goto bail;
+		}
+		plugin->list = context->plugin_list;
+		context->plugin_list = plugin;
+		strncpy(plugin->name, dent.name, sizeof(plugin->name) - 1);
+		plugin->name[sizeof(plugin->name) - 1] = '\0';
+		plugin->lib = lib;
+		plugin->caps = lcaps;
+		context->plugin_protocol_count += lcaps.count_protocols;
+		context->plugin_extension_count += lcaps.count_extensions;
+
+		continue;
+
+skip:
+		uv_dlclose(&lib);
+	}
+
+bail:
+	uv_fs_req_cleanup(&req);
+	uv_loop_close(&loop);
+
+	return ret;
+
+}
+
+LWS_VISIBLE int
+lws_plat_plugins_destroy(struct lws_context * context)
+{
+	struct lws_plugin *plugin = context->plugin_list, *p;
+	lws_plugin_destroy_func func;
+	char path[256];
+	void *v;
+	int m;
+
+	if (!plugin)
+		return 0;
+
+	lwsl_notice("%s\n", __func__);
+
+	while (plugin) {
+		p = plugin;
+		m = snprintf(path, sizeof(path) - 1, "destroy_%s", plugin->name + 3);
+		path[m - 3] = '\0';
+
+		if (uv_dlsym(&plugin->lib, path, &v)) {
+			uv_dlerror(&plugin->lib);
+			lwsl_err("Failed to get init on %s: %s",
+					plugin->name, plugin->lib.errmsg);
+		} else {
+			func = (lws_plugin_destroy_func)v;
+			m = func(context);
+			if (m)
+				lwsl_err("Destroying %s failed %d\n",
+						plugin->name, m);
+		}
+
+		uv_dlclose(&p->lib);
+		plugin = p->list;
+		p->list = NULL;
+		free(p);
+	}
+
+	context->plugin_list = NULL;
+
+	return 0;
+}
+
+#endif
+

lib/libwebsockets.h

@@ -1305,6 +1305,11 @@ struct lws_extension {
 	 * This is part of the ABI, don't needlessly break compatibility */
 };
 
+
+#ifdef LWS_WITH_PLUGINS
+
+/* PLUGINS implies LIBUV */
+
 #define LWS_PLUGIN_API_MAGIC 180
 
 struct lws_plugin_capability {
@@ -1320,11 +1325,17 @@ typedef int (*lws_plugin_init_func)(struct lws_context *,
 typedef int (*lws_plugin_destroy_func)(struct lws_context *);
 struct lws_plugin {
 	struct lws_plugin *list;
+#if (UV_VERSION_MAJOR > 0)
+	uv_lib_t lib;
+#else
 	void *l;
+#endif
 	char name[64];
 	struct lws_plugin_capability caps;
 };
 
+#endif
+
 /*
  * The internal exts are part of the public abi
  * If we add more extensions, publish the callback here  ------v

lib/lws-plat-unix.c

@@ -300,6 +300,12 @@ lws_plat_drop_app_privileges(struct lws_context_creation_info *info)
 
 #ifdef LWS_WITH_PLUGINS
 
+#if defined(LWS_USE_LIBUV) && UV_VERSION_MAJOR > 0
+
+/* libuv.c implements these in a cross-platform way */
+
+#else
+
 static int filter(const struct dirent *ent)
 {
 	if (!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, ".."))
@@ -322,7 +328,7 @@ lws_plat_plugins_init(struct lws_context * context, const char *d)
 
 	n = scandir(d, &namelist, filter, alphasort);
 	if (n < 0) {
-		lwsl_err("Scandir on %d failed\n", d);
+		lwsl_err("Scandir on %s failed\n", d);
 		return 1;
 	}
 
@@ -431,6 +437,7 @@ next:
 }
 
 #endif
+#endif
 
 
 static void

lib/private-libwebsockets.h

@@ -763,6 +763,12 @@ lws_close_free_wsi_final(struct lws *wsi);
 LWS_EXTERN void
 lws_libuv_closehandle(struct lws *wsi);
 
+LWS_VISIBLE LWS_EXTERN int
+lws_plat_plugins_init(struct lws_context * context, const char *d);
+
+LWS_VISIBLE LWS_EXTERN int
+lws_plat_plugins_destroy(struct lws_context * context);
+
 enum {
 	LWS_EV_READ = (1 << 0),
 	LWS_EV_WRITE = (1 << 1),

lwsws/conf.c

@@ -345,6 +345,41 @@ lwsws_get_config(void *user, const char *f, const char * const *paths,
 	return 0;
 }
 
+#if defined(LWS_USE_LIBUV) && UV_VERSION_MAJOR > 0
+
+static int
+lwsws_get_config_d(void *user, const char *d, const char * const *paths,
+		   int count_paths, lejp_callback cb)
+{
+	uv_dirent_t dent;
+	uv_fs_t req;
+	char path[256];
+	int ret = 0;
+	uv_loop_t loop;
+
+	uv_loop_init(&loop);
+
+	if (!uv_fs_scandir(&loop, &req, d, 0, NULL)) {
+		lwsl_err("Scandir on %s failed\n", d);
+		return 1;
+	}
+
+	while (uv_fs_scandir_next(&req, &dent) != UV_EOF) {
+		snprintf(path, sizeof(path) - 1, "%s/%s", d, dent.name);
+		ret = lwsws_get_config(user, path, paths, count_paths, cb);
+		if (ret)
+			goto bail;
+	}
+
+bail:
+	uv_fs_req_cleanup(&req);
+	uv_loop_close(&loop);
+
+	return ret;
+}
+
+#else
+
 #ifndef _WIN32
 static int filter(const struct dirent *ent)
 {
@@ -390,6 +425,8 @@ bail:
 #endif
 }
 
+#endif
+
 int
 lwsws_get_config_globals(struct lws_context_creation_info *info, const char *d,
 			 char **cs, int *len)