add lua plugin support

1 files changed, 280 insertions, 0 deletions

diff --git a/lua.c b/lua.c
new file mode 100644
index 0000000..e404add
--- /dev/null
+++ b/lua.c
@@ -0,0 +1,280 @@
+/*
+ * uhttpd - Tiny single-threaded httpd
+ *
+ *   Copyright (C) 2010-2012 Jo-Philipp Wich <xm@subsignal.org>
+ *   Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+
+#include <libubox/blobmsg.h>
+#include <lua.h>
+#include <lauxlib.h>
+#include <lualib.h>
+#include <stdio.h>
+#include <poll.h>
+
+#include "uhttpd.h"
+#include "plugin.h"
+
+#define UH_LUA_CB	"handle_request"
+
+static const struct uhttpd_ops *ops;
+static struct config *_conf;
+#define conf (*_conf)
+
+static lua_State *_L;
+
+static int uh_lua_recv(lua_State *L)
+{
+	static struct pollfd pfd = {
+		.fd = STDIN_FILENO,
+		.events = POLLIN,
+	};
+	luaL_Buffer B;
+	int data_len = 0;
+	int len;
+	int r;
+
+	len = luaL_checknumber(L, 1);
+	luaL_buffinit(L, &B);
+	while(len > 0) {
+		char *buf;
+
+		buf = luaL_prepbuffer(&B);
+		r = read(STDIN_FILENO, buf, LUAL_BUFFERSIZE);
+		if (r < 0) {
+			if (errno == EWOULDBLOCK || errno == EAGAIN) {
+				pfd.revents = 0;
+				poll(&pfd, 1, 1000);
+				if (pfd.revents & POLLIN)
+					continue;
+			}
+			if (errno == EINTR)
+				continue;
+
+			if (!data_len)
+				data_len = -1;
+			break;
+		}
+		if (!r)
+			break;
+
+		luaL_addsize(&B, r);
+		data_len += r;
+		if (r != LUAL_BUFFERSIZE)
+			break;
+	}
+
+	luaL_pushresult(&B);
+	lua_pushnumber(L, data_len);
+	if (data_len > 0) {
+		lua_pushvalue(L, -2);
+		lua_remove(L, -3);
+		return 2;
+	} else {
+		lua_remove(L, -2);
+		return 1;
+	}
+}
+
+static int
+uh_lua_strconvert(lua_State *L, int (*convert)(char *, int, const char *, int))
+{
+	const char *in_buf;
+	static char out_buf[4096];
+	size_t in_len;
+	int out_len;
+
+	in_buf = luaL_checklstring(L, 1, &in_len);
+	out_len = convert(out_buf, sizeof(out_buf), in_buf, in_len);
+
+	if (out_len < 0) {
+		const char *error;
+
+		if (out_len == -1)
+			error = "buffer overflow";
+		else
+			error = "malformed string";
+
+		luaL_error(L, "%s on URL conversion\n", error);
+	}
+
+	lua_pushlstring(L, out_buf, out_len);
+	return 1;
+}
+
+static int uh_lua_urldecode(lua_State *L)
+{
+	return uh_lua_strconvert(L, ops->urldecode);
+}
+
+static int uh_lua_urlencode(lua_State *L)
+{
+	return uh_lua_strconvert(L, ops->urlencode);
+}
+
+static lua_State *uh_lua_state_init(void)
+{
+	const char *msg = "(unknown error)";
+	const char *status;
+	lua_State *L;
+	int ret;
+
+	L = lua_open();
+	luaL_openlibs(L);
+
+	/* build uhttpd api table */
+	lua_newtable(L);
+
+	/* 
+	 * use print as send and sendc implementation,
+	 * chunked transfer is handled in the main server
+	 */
+	lua_getglobal(L, "print");
+	lua_pushvalue(L, -1);
+	lua_setfield(L, -3, "send");
+	lua_setfield(L, -2, "sendc");
+
+	lua_pushcfunction(L, uh_lua_recv);
+	lua_setfield(L, -2, "recv");
+
+	lua_pushcfunction(L, uh_lua_urldecode);
+	lua_setfield(L, -2, "urldecode");
+
+	lua_pushcfunction(L, uh_lua_urlencode);
+	lua_setfield(L, -2, "urlencode");
+
+	lua_pushstring(L, conf.docroot);
+	lua_setfield(L, -2, "docroot");
+
+	lua_setglobal(L, "uhttpd");
+
+	ret = luaL_loadfile(L, conf.lua_handler);
+	if (ret) {
+		status = "loading";
+		goto error;
+	}
+
+	ret = lua_pcall(L, 0, 0, 0);
+	if (ret) {
+		status = "initializing";
+		goto error;
+	}
+
+	lua_getglobal(L, UH_LUA_CB);
+	if (!lua_isfunction(L, -1)) {
+		fprintf(stderr, "Error: Lua handler provides no " UH_LUA_CB "() callback.\n");
+		exit(1);
+	}
+
+	return L;
+
+error:
+	if (!lua_isnil(L, -1))
+		msg = lua_tostring(L, -1);
+
+	fprintf(stderr, "Error %s Lua handler: %s\n", status, msg);
+	exit(1);
+	return NULL;
+}
+
+static void lua_main(struct client *cl, struct path_info *pi, const char *url)
+{
+	const char *error;
+	struct env_var *var;
+	lua_State *L = _L;
+	int path_len, prefix_len;
+	char *str;
+
+	lua_getglobal(L, UH_LUA_CB);
+
+	/* new env table for this request */
+	lua_newtable(L);
+
+	prefix_len = strlen(conf.lua_prefix);
+	path_len = strlen(url);
+	str = strchr(url, '?');
+	if (str) {
+		pi->query = str;
+		path_len = str - url;
+	}
+	if (path_len > prefix_len) {
+		lua_pushlstring(L, url + prefix_len,
+				path_len - prefix_len);
+		lua_setfield(L, -2, "PATH_INFO");
+	}
+
+	for (var = ops->get_process_vars(cl, pi); var->name; var++) {
+		if (!var->value)
+			continue;
+
+		lua_pushstring(L, var->value);
+		lua_setfield(L, -2, var->name);
+	}
+
+	lua_pushnumber(L, 0.9 + (cl->request.version / 10.0));
+	lua_setfield(L, -2, "HTTP_VERSION");
+
+	switch(lua_pcall(L, 1, 0, 0)) {
+	case LUA_ERRMEM:
+	case LUA_ERRRUN:
+		error = luaL_checkstring(L, -1);
+		if (!error)
+			error = "(unknown error)";
+
+		printf("Status: 500 Internal Server Error\r\n\r\n"
+	       "Unable to launch the requested Lua program:\n"
+	       "  %s: %s\n", pi->phys, strerror(errno));
+	}
+
+	exit(0);
+}
+
+static void lua_handle_request(struct client *cl, const char *url, struct path_info *pi)
+{
+	static struct path_info _pi;
+
+	pi = &_pi;
+	pi->name = conf.lua_prefix;
+	pi->phys = conf.lua_handler;
+
+	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));
+	}
+}
+
+static bool check_lua_url(const char *url)
+{
+	return ops->path_match(conf.lua_prefix, url);
+}
+
+static struct dispatch_handler lua_dispatch = {
+	.check_url = check_lua_url,
+	.handle_request = lua_handle_request,
+};
+
+static int lua_plugin_init(const struct uhttpd_ops *o, struct config *c)
+{
+	ops = o;
+	_conf = c;
+	_L = uh_lua_state_init();
+	ops->dispatch_add(&lua_dispatch);
+	return 0;
+}
+
+const struct uhttpd_plugin uhttpd_plugin = {
+	.init = lua_plugin_init,
+};