lua: support multiple Lua prefixes

Allow -l / -L arguments to be repeated to register multiple Lua prefix
handlers in the same process.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

3 files changed, 100 insertions, 27 deletions

diff --git a/lua.c b/lua.c
index abae88c..0a9bc5a 100644
--- a/lua.c
+++ b/lua.c
@@ -139,7 +139,7 @@ static int uh_lua_urlencode(lua_State *L)
 	return uh_lua_strconvert(L, ops->urlencode);
 }
 
-static lua_State *uh_lua_state_init(void)
+static lua_State *uh_lua_state_init(struct lua_prefix *lua)
 {
 	const char *msg = "(unknown error)";
 	const char *status;
@@ -172,7 +172,7 @@ static lua_State *uh_lua_state_init(void)
 
 	lua_setglobal(L, "uhttpd");
 
-	ret = luaL_loadfile(L, conf.lua_handler);
+	ret = luaL_loadfile(L, lua->handler);
 	if (ret) {
 		status = "loading";
 		goto error;
@@ -186,17 +186,21 @@ static lua_State *uh_lua_state_init(void)
 
 	lua_getglobal(L, UH_LUA_CB);
 	if (!lua_isfunction(L, -1)) {
-		fprintf(stderr, "Error: Lua handler provides no " UH_LUA_CB "() callback.\n");
+		fprintf(stderr, "Error: Lua handler %s provides no "
+		                UH_LUA_CB "() callback.\n", lua->handler);
 		exit(1);
 	}
 
+	lua->ctx = L;
+
 	return L;
 
 error:
 	if (!lua_isnil(L, -1))
 		msg = lua_tostring(L, -1);
 
-	fprintf(stderr, "Error %s Lua handler: %s\n", status, msg);
+	fprintf(stderr, "Error %s %s Lua handler: %s\n",
+	        status, lua->handler, msg);
 	exit(1);
 	return NULL;
 }
@@ -216,7 +220,7 @@ static void lua_main(struct client *cl, struct path_info *pi, char *url)
 	/* new env table for this request */
 	lua_newtable(L);
 
-	prefix_len = strlen(conf.lua_prefix);
+	prefix_len = strlen(pi->name);
 	path_len = strlen(url);
 	str = strchr(url, '?');
 	if (str) {
@@ -225,7 +229,7 @@ static void lua_main(struct client *cl, struct path_info *pi, char *url)
 		path_len = str - url;
 	}
 
-	if (prefix_len > 0 && conf.lua_prefix[prefix_len - 1] == '/')
+	if (prefix_len > 0 && pi->name[prefix_len - 1] == '/')
 		prefix_len--;
 
 	if (path_len > prefix_len) {
@@ -269,21 +273,41 @@ static void lua_main(struct client *cl, struct path_info *pi, char *url)
 
 static void lua_handle_request(struct client *cl, char *url, struct path_info *pi)
 {
+	struct lua_prefix *p;
 	static struct path_info _pi;
 
-	pi = &_pi;
-	pi->name = conf.lua_prefix;
-	pi->phys = conf.lua_handler;
+	list_for_each_entry(p, &conf.lua_prefix, list) {
+		if (!ops->path_match(p->prefix, url))
+			continue;
+
+		pi = &_pi;
+		pi->name = p->prefix;
+		pi->phys = p->handler;
+
+		_L = p->ctx;
+
+		if (!ops->create_process(cl, pi, url, lua_main)) {
+			ops->client_error(cl, 500, "Internal Server Error",
+			                  "Failed to create CGI process: %s",
+			                  strerror(errno));
+		}
 
-	if (!ops->create_process(cl, pi, url, lua_main)) {
-		ops->client_error(cl, 500, "Internal Server Error",
-				  "Failed to create CGI process: %s", strerror(errno));
+		return;
 	}
+
+	ops->client_error(cl, 500, "Internal Server Error",
+	                  "Failed to lookup matching handler");
 }
 
 static bool check_lua_url(const char *url)
 {
-	return ops->path_match(conf.lua_prefix, url);
+	struct lua_prefix *p;
+
+	list_for_each_entry(p, &conf.lua_prefix, list)
+		if (ops->path_match(p->prefix, url))
+			return true;
+
+	return false;
 }
 
 static struct dispatch_handler lua_dispatch = {
@@ -294,9 +318,14 @@ static struct dispatch_handler lua_dispatch = {
 
 static int lua_plugin_init(const struct uhttpd_ops *o, struct config *c)
 {
+	struct lua_prefix *p;
+
 	ops = o;
 	_conf = c;
-	_L = uh_lua_state_init();
+
+	list_for_each_entry(p, &conf.lua_prefix, list)
+		uh_lua_state_init(p);
+
 	ops->dispatch_add(&lua_dispatch);
 	return 0;
 }
diff --git a/main.c b/main.c
index 11b33ff..6574c15 100644
--- a/main.c
+++ b/main.c
@@ -31,6 +31,7 @@
 #include <signal.h>
 
 #include <libubox/usock.h>
+#include <libubox/utils.h>
 
 #include "uhttpd.h"
 #include "tls.h"
@@ -180,6 +181,7 @@ static void init_defaults_pre(void)
 	conf.cgi_prefix = "/cgi-bin";
 	conf.cgi_path = "/sbin:/usr/sbin:/bin:/usr/bin";
 	INIT_LIST_HEAD(&conf.cgi_alias);
+	INIT_LIST_HEAD(&conf.lua_prefix);
 }
 
 static void init_defaults_post(void)
@@ -214,6 +216,23 @@ static void fixup_prefix(char *str)
 	str[len + 1] = 0;
 }
 
+static void add_lua_prefix(const char *prefix, const char *handler) {
+	struct lua_prefix *p;
+	char *pprefix, *phandler;
+
+	p = calloc_a(sizeof(*p),
+	             &pprefix, strlen(prefix) + 1,
+	             &phandler, strlen(handler) + 1);
+
+	if (!p)
+		return;
+
+	p->prefix = strcpy(pprefix, prefix);
+	p->handler = strcpy(phandler, handler);
+
+	list_add_tail(&p->list, &conf.lua_prefix);
+}
+
 int main(int argc, char **argv)
 {
 	struct alias *alias;
@@ -226,6 +245,9 @@ int main(int argc, char **argv)
 	int n_tls = 0;
 	const char *tls_key = NULL, *tls_crt = NULL;
 #endif
+#ifdef HAVE_LUA
+	const char *lua_prefix = NULL, *lua_handler = NULL;
+#endif
 
 	BUILD_BUG_ON(sizeof(uh_buf) < PATH_MAX);
 
@@ -410,11 +432,28 @@ int main(int argc, char **argv)
 
 #ifdef HAVE_LUA
 		case 'l':
-			conf.lua_prefix = optarg;
-			break;
-
 		case 'L':
-			conf.lua_handler = optarg;
+			if (ch == 'l') {
+				if (lua_prefix)
+					fprintf(stderr, "uhttpd: Ignoring previous -%c %s\n",
+					        ch, lua_prefix);
+
+				lua_prefix = optarg;
+			}
+			else {
+				if (lua_handler)
+					fprintf(stderr, "uhttpd: Ignoring previous -%c %s\n",
+					        ch, lua_handler);
+
+				lua_handler = optarg;
+			}
+
+			if (lua_prefix && lua_handler) {
+				add_lua_prefix(lua_prefix, lua_handler);
+				lua_prefix = NULL;
+				lua_handler = NULL;
+			}
+
 			break;
 #else
 		case 'l':
@@ -484,14 +523,13 @@ int main(int argc, char **argv)
 #endif
 
 #ifdef HAVE_LUA
-	if (conf.lua_handler || conf.lua_prefix) {
-		if (!conf.lua_handler || !conf.lua_prefix) {
-			fprintf(stderr, "Need handler and prefix to enable Lua support\n");
-			return 1;
-		}
-		if (uh_plugin_init("uhttpd_lua.so"))
-			return 1;
+	if (lua_handler || lua_prefix) {
+		fprintf(stderr, "Need handler and prefix to enable Lua support\n");
+		return 1;
 	}
+
+	if (!list_empty(&conf.lua_prefix) && uh_plugin_init("uhttpd_lua.so"))
+		return 1;
 #endif
 #ifdef HAVE_UBUS
 	if (conf.ubus_prefix && uh_plugin_init("uhttpd_ubus.so"))
diff --git a/uhttpd.h b/uhttpd.h
index 8d6022a..f77718e 100644
--- a/uhttpd.h
+++ b/uhttpd.h
@@ -52,6 +52,13 @@ struct alias {
 	char *path;
 };
 
+struct lua_prefix {
+	struct list_head list;
+	const char *handler;
+	const char *prefix;
+	void *ctx;
+};
+
 struct config {
 	const char *docroot;
 	const char *realm;
@@ -60,8 +67,6 @@ struct config {
 	const char *cgi_prefix;
 	const char *cgi_docroot_path;
 	const char *cgi_path;
-	const char *lua_handler;
-	const char *lua_prefix;
 	const char *ubus_prefix;
 	const char *ubus_socket;
 	int no_symlinks;
@@ -78,6 +83,7 @@ struct config {
 	int ubus_cors;
 	int cgi_prefix_len;
 	struct list_head cgi_alias;
+	struct list_head lua_prefix;
 };
 
 struct auth_realm {