lua.c

   1 /*
   2  * uhttpd - Tiny single-threaded httpd
   3  *
   4  *   Copyright (C) 2010-2012 Jo-Philipp Wich <xm@subsignal.org>
   5  *   Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
   6  *
   7  *  Licensed under the Apache License, Version 2.0 (the "License");
   8  *  you may not use this file except in compliance with the License.
   9  *  You may obtain a copy of the License at
  10  *
  11  *      http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  *  Unless required by applicable law or agreed to in writing, software
  14  *  distributed under the License is distributed on an "AS IS" BASIS,
  15  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  *  See the License for the specific language governing permissions and
  17  *  limitations under the License.
  18  */
  19
  20
  21 #include <libubox/blobmsg.h>
  22 #include <lua.h>
  23 #include <lauxlib.h>
  24 #include <lualib.h>
  25 #include <stdio.h>
  26 #include <poll.h>
  27
  28 #include "uhttpd.h"
  29 #include "plugin.h"
  30
  31 #define UH_LUA_CB       "handle_request"
  32
  33 static const struct uhttpd_ops *ops;
  34 static struct config *_conf;
  35 #define conf (*_conf)
  36
  37 static lua_State *_L;
  38
  39 static int uh_lua_recv(lua_State *L)
  40 {
  41         static struct pollfd pfd = {
  42                 .fd = STDIN_FILENO,
  43                 .events = POLLIN,
  44         };
  45         luaL_Buffer B;
  46         int data_len = 0;
  47         int len;
  48         int r;
  49
  50         len = luaL_checknumber(L, 1);
  51         luaL_buffinit(L, &B);
  52         while(len > 0) {
  53                 char *buf;
  54
  55                 buf = luaL_prepbuffer(&B);
  56                 r = read(STDIN_FILENO, buf, LUAL_BUFFERSIZE);
  57                 if (r < 0) {
  58                         if (errno == EWOULDBLOCK || errno == EAGAIN) {
  59                                 pfd.revents = 0;
  60                                 poll(&pfd, 1, 1000);
  61                                 if (pfd.revents & POLLIN)
  62                                         continue;
  63                         }
  64                         if (errno == EINTR)
  65                                 continue;
  66
  67                         if (!data_len)
  68                                 data_len = -1;
  69                         break;
  70                 }
  71                 if (!r)
  72                         break;
  73
  74                 luaL_addsize(&B, r);
  75                 data_len += r;
  76                 if (r != LUAL_BUFFERSIZE)
  77                         break;
  78         }
  79
  80         luaL_pushresult(&B);
  81         lua_pushnumber(L, data_len);
  82         if (data_len > 0) {
  83                 lua_pushvalue(L, -2);
  84                 lua_remove(L, -3);
  85                 return 2;
  86         } else {
  87                 lua_remove(L, -2);
  88                 return 1;
  89         }
  90 }
  91
  92 static int
  93 uh_lua_strconvert(lua_State *L, int (*convert)(char *, int, const char *, int))
  94 {
  95         const char *in_buf;
  96         static char out_buf[4096];
  97         size_t in_len;
  98         int out_len;
  99
 100         in_buf = luaL_checklstring(L, 1, &in_len);
 101         out_len = convert(out_buf, sizeof(out_buf), in_buf, in_len);
 102
 103         if (out_len < 0) {
 104                 const char *error;
 105
 106                 if (out_len == -1)
 107                         error = "buffer overflow";
 108                 else
 109                         error = "malformed string";
 110
 111                 luaL_error(L, "%s on URL conversion\n", error);
 112         }
 113
 114         lua_pushlstring(L, out_buf, out_len);
 115         return 1;
 116 }
 117
 118 static int uh_lua_urldecode(lua_State *L)
 119 {
 120         return uh_lua_strconvert(L, ops->urldecode);
 121 }
 122
 123 static int uh_lua_urlencode(lua_State *L)
 124 {
 125         return uh_lua_strconvert(L, ops->urlencode);
 126 }
 127
 128 static lua_State *uh_lua_state_init(void)
 129 {
 130         const char *msg = "(unknown error)";
 131         const char *status;
 132         lua_State *L;
 133         int ret;
 134
 135         L = lua_open();
 136         luaL_openlibs(L);
 137
 138         /* build uhttpd api table */
 139         lua_newtable(L);
 140
 141         /*
 142          * use print as send and sendc implementation,
 143          * chunked transfer is handled in the main server
 144          */
 145         lua_getglobal(L, "print");
 146         lua_pushvalue(L, -1);
 147         lua_setfield(L, -3, "send");
 148         lua_setfield(L, -2, "sendc");
 149
 150         lua_pushcfunction(L, uh_lua_recv);
 151         lua_setfield(L, -2, "recv");
 152
 153         lua_pushcfunction(L, uh_lua_urldecode);
 154         lua_setfield(L, -2, "urldecode");
 155
 156         lua_pushcfunction(L, uh_lua_urlencode);
 157         lua_setfield(L, -2, "urlencode");
 158
 159         lua_pushstring(L, conf.docroot);
 160         lua_setfield(L, -2, "docroot");
 161
 162         lua_setglobal(L, "uhttpd");
 163
 164         ret = luaL_loadfile(L, conf.lua_handler);
 165         if (ret) {
 166                 status = "loading";
 167                 goto error;
 168         }
 169
 170         ret = lua_pcall(L, 0, 0, 0);
 171         if (ret) {
 172                 status = "initializing";
 173                 goto error;
 174         }
 175
 176         lua_getglobal(L, UH_LUA_CB);
 177         if (!lua_isfunction(L, -1)) {
 178                 fprintf(stderr, "Error: Lua handler provides no " UH_LUA_CB "() callback.\n");
 179                 exit(1);
 180         }
 181
 182         return L;
 183
 184 error:
 185         if (!lua_isnil(L, -1))
 186                 msg = lua_tostring(L, -1);
 187
 188         fprintf(stderr, "Error %s Lua handler: %s\n", status, msg);
 189         exit(1);
 190         return NULL;
 191 }
 192
 193 static void lua_main(struct client *cl, struct path_info *pi, const char *url)
 194 {
 195         const char *error;
 196         struct env_var *var;
 197         lua_State *L = _L;
 198         int path_len, prefix_len;
 199         char *str;
 200
 201         lua_getglobal(L, UH_LUA_CB);
 202
 203         /* new env table for this request */
 204         lua_newtable(L);
 205
 206         prefix_len = strlen(conf.lua_prefix);
 207         path_len = strlen(url);
 208         str = strchr(url, '?');
 209         if (str) {
 210                 pi->query = str;
 211                 path_len = str - url;
 212         }
 213         if (path_len > prefix_len) {
 214                 lua_pushlstring(L, url + prefix_len,
 215                                 path_len - prefix_len);
 216                 lua_setfield(L, -2, "PATH_INFO");
 217         }
 218
 219         for (var = ops->get_process_vars(cl, pi); var->name; var++) {
 220                 if (!var->value)
 221                         continue;
 222
 223                 lua_pushstring(L, var->value);
 224                 lua_setfield(L, -2, var->name);
 225         }
 226
 227         lua_pushnumber(L, 0.9 + (cl->request.version / 10.0));
 228         lua_setfield(L, -2, "HTTP_VERSION");
 229
 230         switch(lua_pcall(L, 1, 0, 0)) {
 231         case LUA_ERRMEM:
 232         case LUA_ERRRUN:
 233                 error = luaL_checkstring(L, -1);
 234                 if (!error)
 235                         error = "(unknown error)";
 236
 237                 printf("Status: 500 Internal Server Error\r\n\r\n"
 238                "Unable to launch the requested Lua program:\n"
 239                "  %s: %s\n", pi->phys, strerror(errno));
 240         }
 241
 242         exit(0);
 243 }
 244
 245 static void lua_handle_request(struct client *cl, const char *url, struct path_info *pi)
 246 {
 247         static struct path_info _pi;
 248
 249         pi = &_pi;
 250         pi->name = conf.lua_prefix;
 251         pi->phys = conf.lua_handler;
 252
 253         if (!ops->create_process(cl, pi, url, lua_main)) {
 254                 ops->client_error(cl, 500, "Internal Server Error",
 255                                   "Failed to create CGI process: %s", strerror(errno));
 256         }
 257 }
 258
 259 static bool check_lua_url(const char *url)
 260 {
 261         return ops->path_match(conf.lua_prefix, url);
 262 }
 263
 264 static struct dispatch_handler lua_dispatch = {
 265         .check_url = check_lua_url,
 266         .handle_request = lua_handle_request,
 267 };
 268
 269 static int lua_plugin_init(const struct uhttpd_ops *o, struct config *c)
 270 {
 271         ops = o;
 272         _conf = c;
 273         _L = uh_lua_state_init();
 274         ops->dispatch_add(&lua_dispatch);
 275         return 0;
 276 }
 277
 278 const struct uhttpd_plugin uhttpd_plugin = {
 279         .init = lua_plugin_init,
 280 };