| 1 | /* |
| 2 | * uhttpd - Tiny single-threaded httpd - Lua handler |
| 3 | * |
| 4 | * Copyright (C) 2010 Jo-Philipp Wich <xm@subsignal.org> |
| 5 | * |
| 6 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 7 | * you may not use this file except in compliance with the License. |
| 8 | * You may obtain a copy of the License at |
| 9 | * |
| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 11 | * |
| 12 | * Unless required by applicable law or agreed to in writing, software |
| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 15 | * See the License for the specific language governing permissions and |
| 16 | * limitations under the License. |
| 17 | */ |
| 18 | |
| 19 | #include "uhttpd.h" |
| 20 | #include "uhttpd-utils.h" |
| 21 | #include "uhttpd-lua.h" |
| 22 | |
| 23 | |
| 24 | static int uh_lua_recv(lua_State *L) |
| 25 | { |
| 26 | size_t length; |
| 27 | char buffer[UH_LIMIT_MSGHEAD]; |
| 28 | ssize_t rlen = 0; |
| 29 | fd_set reader; |
| 30 | struct timeval timeout; |
| 31 | |
| 32 | length = luaL_checknumber(L, 1); |
| 33 | |
| 34 | if( (length > 0) && (length <= sizeof(buffer)) ) |
| 35 | { |
| 36 | FD_ZERO(&reader); |
| 37 | FD_SET(fileno(stdin), &reader); |
| 38 | |
| 39 | /* fail after 0.1s */ |
| 40 | timeout.tv_sec = 0; |
| 41 | timeout.tv_usec = 100000; |
| 42 | |
| 43 | /* check whether fd is readable */ |
| 44 | if( select(fileno(stdin) + 1, &reader, NULL, NULL, &timeout) > 0 ) |
| 45 | { |
| 46 | /* receive data */ |
| 47 | rlen = read(fileno(stdin), buffer, length); |
| 48 | lua_pushnumber(L, rlen); |
| 49 | |
| 50 | if( rlen > 0 ) |
| 51 | { |
| 52 | lua_pushlstring(L, buffer, rlen); |
| 53 | return 2; |
| 54 | } |
| 55 | |
| 56 | return 1; |
| 57 | } |
| 58 | |
| 59 | /* no, timeout and actually no data */ |
| 60 | lua_pushnumber(L, -2); |
| 61 | return 1; |
| 62 | } |
| 63 | |
| 64 | /* parameter error */ |
| 65 | lua_pushnumber(L, -3); |
| 66 | return 1; |
| 67 | } |
| 68 | |
| 69 | static int uh_lua_send_common(lua_State *L, int chunked) |
| 70 | { |
| 71 | size_t length; |
| 72 | const char *buffer; |
| 73 | char chunk[16]; |
| 74 | ssize_t slen = 0; |
| 75 | |
| 76 | buffer = luaL_checklstring(L, 1, &length); |
| 77 | |
| 78 | if( chunked ) |
| 79 | { |
| 80 | if( length > 0 ) |
| 81 | { |
| 82 | snprintf(chunk, sizeof(chunk), "%X\r\n", length); |
| 83 | slen = write(fileno(stdout), chunk, strlen(chunk)); |
| 84 | slen += write(fileno(stdout), buffer, length); |
| 85 | slen += write(fileno(stdout), "\r\n", 2); |
| 86 | } |
| 87 | else |
| 88 | { |
| 89 | slen = write(fileno(stdout), "0\r\n\r\n", 5); |
| 90 | } |
| 91 | } |
| 92 | else |
| 93 | { |
| 94 | slen = write(fileno(stdout), buffer, length); |
| 95 | } |
| 96 | |
| 97 | lua_pushnumber(L, slen); |
| 98 | return 1; |
| 99 | } |
| 100 | |
| 101 | static int uh_lua_send(lua_State *L) |
| 102 | { |
| 103 | return uh_lua_send_common(L, 0); |
| 104 | } |
| 105 | |
| 106 | static int uh_lua_sendc(lua_State *L) |
| 107 | { |
| 108 | return uh_lua_send_common(L, 1); |
| 109 | } |
| 110 | |
| 111 | static int uh_lua_urldecode(lua_State *L) |
| 112 | { |
| 113 | size_t inlen, outlen; |
| 114 | const char *inbuf; |
| 115 | char outbuf[UH_LIMIT_MSGHEAD]; |
| 116 | |
| 117 | inbuf = luaL_checklstring(L, 1, &inlen); |
| 118 | outlen = uh_urldecode(outbuf, sizeof(outbuf), inbuf, inlen); |
| 119 | |
| 120 | lua_pushlstring(L, outbuf, outlen); |
| 121 | return 1; |
| 122 | } |
| 123 | |
| 124 | |
| 125 | lua_State * uh_lua_init(const char *handler) |
| 126 | { |
| 127 | lua_State *L = lua_open(); |
| 128 | const char *err_str = NULL; |
| 129 | |
| 130 | /* Load standard libaries */ |
| 131 | luaL_openlibs(L); |
| 132 | |
| 133 | /* build uhttpd api table */ |
| 134 | lua_newtable(L); |
| 135 | |
| 136 | /* register global send and receive functions */ |
| 137 | lua_pushcfunction(L, uh_lua_recv); |
| 138 | lua_setfield(L, -2, "recv"); |
| 139 | |
| 140 | lua_pushcfunction(L, uh_lua_send); |
| 141 | lua_setfield(L, -2, "send"); |
| 142 | |
| 143 | lua_pushcfunction(L, uh_lua_sendc); |
| 144 | lua_setfield(L, -2, "sendc"); |
| 145 | |
| 146 | lua_pushcfunction(L, uh_lua_urldecode); |
| 147 | lua_setfield(L, -2, "urldecode"); |
| 148 | |
| 149 | /* _G.uhttpd = { ... } */ |
| 150 | lua_setfield(L, LUA_GLOBALSINDEX, "uhttpd"); |
| 151 | |
| 152 | |
| 153 | /* load Lua handler */ |
| 154 | switch( luaL_loadfile(L, handler) ) |
| 155 | { |
| 156 | case LUA_ERRSYNTAX: |
| 157 | fprintf(stderr, |
| 158 | "Lua handler contains syntax errors, unable to continue\n"); |
| 159 | exit(1); |
| 160 | |
| 161 | case LUA_ERRMEM: |
| 162 | fprintf(stderr, |
| 163 | "Lua handler ran out of memory, unable to continue\n"); |
| 164 | exit(1); |
| 165 | |
| 166 | case LUA_ERRFILE: |
| 167 | fprintf(stderr, |
| 168 | "Lua cannot open the handler script, unable to continue\n"); |
| 169 | exit(1); |
| 170 | |
| 171 | default: |
| 172 | /* compile Lua handler */ |
| 173 | switch( lua_pcall(L, 0, 0, 0) ) |
| 174 | { |
| 175 | case LUA_ERRRUN: |
| 176 | err_str = luaL_checkstring(L, -1); |
| 177 | fprintf(stderr, |
| 178 | "Lua handler had runtime error, unable to continue\n" |
| 179 | "Error: %s\n", err_str |
| 180 | ); |
| 181 | exit(1); |
| 182 | |
| 183 | case LUA_ERRMEM: |
| 184 | err_str = luaL_checkstring(L, -1); |
| 185 | fprintf(stderr, |
| 186 | "Lua handler ran out of memory, unable to continue\n" |
| 187 | "Error: %s\n", err_str |
| 188 | ); |
| 189 | exit(1); |
| 190 | |
| 191 | default: |
| 192 | /* test handler function */ |
| 193 | lua_getglobal(L, UH_LUA_CALLBACK); |
| 194 | |
| 195 | if( ! lua_isfunction(L, -1) ) |
| 196 | { |
| 197 | fprintf(stderr, |
| 198 | "Lua handler provides no " UH_LUA_CALLBACK "(), unable to continue\n"); |
| 199 | exit(1); |
| 200 | } |
| 201 | |
| 202 | lua_pop(L, 1); |
| 203 | break; |
| 204 | } |
| 205 | |
| 206 | break; |
| 207 | } |
| 208 | |
| 209 | return L; |
| 210 | } |
| 211 | |
| 212 | void uh_lua_request(struct client *cl, struct http_request *req, lua_State *L) |
| 213 | { |
| 214 | int i, data_sent; |
| 215 | int content_length = 0; |
| 216 | int buflen = 0; |
| 217 | int fd_max = 0; |
| 218 | char *query_string; |
| 219 | const char *prefix = cl->server->conf->lua_prefix; |
| 220 | const char *err_str = NULL; |
| 221 | |
| 222 | int rfd[2] = { 0, 0 }; |
| 223 | int wfd[2] = { 0, 0 }; |
| 224 | |
| 225 | char buf[UH_LIMIT_MSGHEAD]; |
| 226 | |
| 227 | pid_t child; |
| 228 | |
| 229 | fd_set reader; |
| 230 | fd_set writer; |
| 231 | |
| 232 | struct sigaction sa; |
| 233 | struct timeval timeout; |
| 234 | |
| 235 | |
| 236 | /* spawn pipes for me->child, child->me */ |
| 237 | if( (pipe(rfd) < 0) || (pipe(wfd) < 0) ) |
| 238 | { |
| 239 | uh_http_sendhf(cl, 500, "Internal Server Error", |
| 240 | "Failed to create pipe: %s", strerror(errno)); |
| 241 | |
| 242 | if( rfd[0] > 0 ) close(rfd[0]); |
| 243 | if( rfd[1] > 0 ) close(rfd[1]); |
| 244 | if( wfd[0] > 0 ) close(wfd[0]); |
| 245 | if( wfd[1] > 0 ) close(wfd[1]); |
| 246 | |
| 247 | return; |
| 248 | } |
| 249 | |
| 250 | |
| 251 | switch( (child = fork()) ) |
| 252 | { |
| 253 | case -1: |
| 254 | uh_http_sendhf(cl, 500, "Internal Server Error", |
| 255 | "Failed to fork child: %s", strerror(errno)); |
| 256 | break; |
| 257 | |
| 258 | case 0: |
| 259 | /* restore SIGTERM */ |
| 260 | sa.sa_flags = 0; |
| 261 | sa.sa_handler = SIG_DFL; |
| 262 | sigemptyset(&sa.sa_mask); |
| 263 | sigaction(SIGTERM, &sa, NULL); |
| 264 | |
| 265 | /* close loose pipe ends */ |
| 266 | close(rfd[0]); |
| 267 | close(wfd[1]); |
| 268 | |
| 269 | /* patch stdout and stdin to pipes */ |
| 270 | dup2(rfd[1], 1); |
| 271 | dup2(wfd[0], 0); |
| 272 | |
| 273 | /* put handler callback on stack */ |
| 274 | lua_getglobal(L, UH_LUA_CALLBACK); |
| 275 | |
| 276 | /* build env table */ |
| 277 | lua_newtable(L); |
| 278 | |
| 279 | /* request method */ |
| 280 | switch(req->method) |
| 281 | { |
| 282 | case UH_HTTP_MSG_GET: |
| 283 | lua_pushstring(L, "GET"); |
| 284 | break; |
| 285 | |
| 286 | case UH_HTTP_MSG_HEAD: |
| 287 | lua_pushstring(L, "HEAD"); |
| 288 | break; |
| 289 | |
| 290 | case UH_HTTP_MSG_POST: |
| 291 | lua_pushstring(L, "POST"); |
| 292 | break; |
| 293 | } |
| 294 | |
| 295 | lua_setfield(L, -2, "REQUEST_METHOD"); |
| 296 | |
| 297 | /* request url */ |
| 298 | lua_pushstring(L, req->url); |
| 299 | lua_setfield(L, -2, "REQUEST_URI"); |
| 300 | |
| 301 | /* script name */ |
| 302 | lua_pushstring(L, cl->server->conf->lua_prefix); |
| 303 | lua_setfield(L, -2, "SCRIPT_NAME"); |
| 304 | |
| 305 | /* query string, path info */ |
| 306 | if( (query_string = strchr(req->url, '?')) != NULL ) |
| 307 | { |
| 308 | lua_pushstring(L, query_string + 1); |
| 309 | lua_setfield(L, -2, "QUERY_STRING"); |
| 310 | |
| 311 | if( (int)(query_string - req->url) > strlen(prefix) ) |
| 312 | { |
| 313 | lua_pushlstring(L, |
| 314 | &req->url[strlen(prefix)], |
| 315 | (int)(query_string - req->url) - strlen(prefix) |
| 316 | ); |
| 317 | |
| 318 | lua_setfield(L, -2, "PATH_INFO"); |
| 319 | } |
| 320 | } |
| 321 | else if( strlen(req->url) > strlen(prefix) ) |
| 322 | { |
| 323 | lua_pushstring(L, &req->url[strlen(prefix)]); |
| 324 | lua_setfield(L, -2, "PATH_INFO"); |
| 325 | } |
| 326 | |
| 327 | /* http protcol version */ |
| 328 | lua_pushnumber(L, floor(req->version * 10) / 10); |
| 329 | lua_setfield(L, -2, "HTTP_VERSION"); |
| 330 | |
| 331 | if( req->version > 1.0 ) |
| 332 | lua_pushstring(L, "HTTP/1.1"); |
| 333 | else |
| 334 | lua_pushstring(L, "HTTP/1.0"); |
| 335 | |
| 336 | lua_setfield(L, -2, "SERVER_PROTOCOL"); |
| 337 | |
| 338 | |
| 339 | /* address information */ |
| 340 | lua_pushstring(L, sa_straddr(&cl->peeraddr)); |
| 341 | lua_setfield(L, -2, "REMOTE_ADDR"); |
| 342 | |
| 343 | lua_pushinteger(L, sa_port(&cl->peeraddr)); |
| 344 | lua_setfield(L, -2, "REMOTE_PORT"); |
| 345 | |
| 346 | lua_pushstring(L, sa_straddr(&cl->servaddr)); |
| 347 | lua_setfield(L, -2, "SERVER_ADDR"); |
| 348 | |
| 349 | lua_pushinteger(L, sa_port(&cl->servaddr)); |
| 350 | lua_setfield(L, -2, "SERVER_PORT"); |
| 351 | |
| 352 | /* essential env vars */ |
| 353 | foreach_header(i, req->headers) |
| 354 | { |
| 355 | if( !strcasecmp(req->headers[i], "Content-Length") ) |
| 356 | { |
| 357 | lua_pushnumber(L, atoi(req->headers[i+1])); |
| 358 | lua_setfield(L, -2, "CONTENT_LENGTH"); |
| 359 | } |
| 360 | else if( !strcasecmp(req->headers[i], "Content-Type") ) |
| 361 | { |
| 362 | lua_pushstring(L, req->headers[i+1]); |
| 363 | lua_setfield(L, -2, "CONTENT_TYPE"); |
| 364 | } |
| 365 | } |
| 366 | |
| 367 | /* misc. headers */ |
| 368 | lua_newtable(L); |
| 369 | |
| 370 | foreach_header(i, req->headers) |
| 371 | { |
| 372 | if( strcasecmp(req->headers[i], "Content-Length") && |
| 373 | strcasecmp(req->headers[i], "Content-Type") |
| 374 | ) { |
| 375 | lua_pushstring(L, req->headers[i+1]); |
| 376 | lua_setfield(L, -2, req->headers[i]); |
| 377 | } |
| 378 | } |
| 379 | |
| 380 | lua_setfield(L, -2, "headers"); |
| 381 | |
| 382 | |
| 383 | /* call */ |
| 384 | switch( lua_pcall(L, 1, 0, 0) ) |
| 385 | { |
| 386 | case LUA_ERRMEM: |
| 387 | case LUA_ERRRUN: |
| 388 | err_str = luaL_checkstring(L, -1); |
| 389 | |
| 390 | if( ! err_str ) |
| 391 | err_str = "Unknown error"; |
| 392 | |
| 393 | printf( |
| 394 | "HTTP/%.1f 500 Internal Server Error\r\n" |
| 395 | "Connection: close\r\n" |
| 396 | "Content-Type: text/plain\r\n" |
| 397 | "Content-Length: %i\r\n\r\n" |
| 398 | "Lua raised a runtime error:\n %s\n", |
| 399 | req->version, 31 + strlen(err_str), err_str |
| 400 | ); |
| 401 | |
| 402 | break; |
| 403 | |
| 404 | default: |
| 405 | break; |
| 406 | } |
| 407 | |
| 408 | close(wfd[0]); |
| 409 | close(rfd[1]); |
| 410 | exit(0); |
| 411 | |
| 412 | break; |
| 413 | |
| 414 | /* parent; handle I/O relaying */ |
| 415 | default: |
| 416 | /* close unneeded pipe ends */ |
| 417 | close(rfd[1]); |
| 418 | close(wfd[0]); |
| 419 | |
| 420 | /* max watch fd */ |
| 421 | fd_max = max(rfd[0], wfd[1]) + 1; |
| 422 | |
| 423 | /* find content length */ |
| 424 | if( req->method == UH_HTTP_MSG_POST ) |
| 425 | { |
| 426 | foreach_header(i, req->headers) |
| 427 | { |
| 428 | if( ! strcasecmp(req->headers[i], "Content-Length") ) |
| 429 | { |
| 430 | content_length = atoi(req->headers[i+1]); |
| 431 | break; |
| 432 | } |
| 433 | } |
| 434 | } |
| 435 | |
| 436 | |
| 437 | #define ensure(x) \ |
| 438 | do { if( x < 0 ) goto out; } while(0) |
| 439 | |
| 440 | data_sent = 0; |
| 441 | |
| 442 | timeout.tv_sec = cl->server->conf->script_timeout; |
| 443 | timeout.tv_usec = 0; |
| 444 | |
| 445 | /* I/O loop, watch our pipe ends and dispatch child reads/writes from/to socket */ |
| 446 | while( 1 ) |
| 447 | { |
| 448 | FD_ZERO(&reader); |
| 449 | FD_ZERO(&writer); |
| 450 | |
| 451 | FD_SET(rfd[0], &reader); |
| 452 | FD_SET(wfd[1], &writer); |
| 453 | |
| 454 | /* wait until we can read or write or both */ |
| 455 | if( select_intr(fd_max, &reader, |
| 456 | (content_length > -1) ? &writer : NULL, NULL, |
| 457 | (data_sent < 1) ? &timeout : NULL) > 0 |
| 458 | ) { |
| 459 | /* ready to write to Lua child */ |
| 460 | if( FD_ISSET(wfd[1], &writer) ) |
| 461 | { |
| 462 | /* there is unread post data waiting */ |
| 463 | if( content_length > 0 ) |
| 464 | { |
| 465 | /* read it from socket ... */ |
| 466 | if( (buflen = uh_tcp_recv(cl, buf, min(content_length, sizeof(buf)))) > 0 ) |
| 467 | { |
| 468 | /* ... and write it to child's stdin */ |
| 469 | if( write(wfd[1], buf, buflen) < 0 ) |
| 470 | perror("write()"); |
| 471 | |
| 472 | content_length -= buflen; |
| 473 | } |
| 474 | |
| 475 | /* unexpected eof! */ |
| 476 | else |
| 477 | { |
| 478 | if( write(wfd[1], "", 0) < 0 ) |
| 479 | perror("write()"); |
| 480 | |
| 481 | content_length = 0; |
| 482 | } |
| 483 | } |
| 484 | |
| 485 | /* there is no more post data, close pipe to child's stdin */ |
| 486 | else if( content_length > -1 ) |
| 487 | { |
| 488 | close(wfd[1]); |
| 489 | content_length = -1; |
| 490 | } |
| 491 | } |
| 492 | |
| 493 | /* ready to read from Lua child */ |
| 494 | if( FD_ISSET(rfd[0], &reader) ) |
| 495 | { |
| 496 | /* read data from child ... */ |
| 497 | if( (buflen = read(rfd[0], buf, sizeof(buf))) > 0 ) |
| 498 | { |
| 499 | /* pass through buffer to socket */ |
| 500 | ensure(uh_tcp_send(cl, buf, buflen)); |
| 501 | data_sent = 1; |
| 502 | } |
| 503 | |
| 504 | /* looks like eof from child */ |
| 505 | else |
| 506 | { |
| 507 | /* error? */ |
| 508 | if( ! data_sent ) |
| 509 | uh_http_sendhf(cl, 500, "Internal Server Error", |
| 510 | "The Lua child did not produce any response"); |
| 511 | |
| 512 | break; |
| 513 | } |
| 514 | } |
| 515 | } |
| 516 | |
| 517 | /* timeout exceeded or interrupted by SIGCHLD */ |
| 518 | else |
| 519 | { |
| 520 | if( (errno != EINTR) && ! data_sent ) |
| 521 | { |
| 522 | ensure(uh_http_sendhf(cl, 504, "Gateway Timeout", |
| 523 | "The Lua script took too long to produce " |
| 524 | "a response")); |
| 525 | } |
| 526 | |
| 527 | break; |
| 528 | } |
| 529 | } |
| 530 | |
| 531 | out: |
| 532 | close(rfd[0]); |
| 533 | close(wfd[1]); |
| 534 | |
| 535 | if( !kill(child, 0) ) |
| 536 | { |
| 537 | kill(child, SIGTERM); |
| 538 | waitpid(child, NULL, 0); |
| 539 | } |
| 540 | |
| 541 | break; |
| 542 | } |
| 543 | } |
| 544 | |
| 545 | void uh_lua_close(lua_State *L) |
| 546 | { |
| 547 | lua_close(L); |
| 548 | } |
| 549 | |
