| 1 | /* |
| 2 | * uhttpd - Tiny single-threaded httpd - CGI handler |
| 3 | * |
| 4 | * Copyright (C) 2010-2012 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-cgi.h" |
| 22 | |
| 23 | |
| 24 | static bool |
| 25 | uh_cgi_header_parse(struct http_response *res, char *buf, int len, int *off) |
| 26 | { |
| 27 | char *bufptr = NULL; |
| 28 | char *hdrname = NULL; |
| 29 | int hdrcount = 0; |
| 30 | int pos = 0; |
| 31 | |
| 32 | if (((bufptr = strfind(buf, len, "\r\n\r\n", 4)) != NULL) || |
| 33 | ((bufptr = strfind(buf, len, "\n\n", 2)) != NULL)) |
| 34 | { |
| 35 | *off = (int)(bufptr - buf) + ((bufptr[0] == '\r') ? 4 : 2); |
| 36 | |
| 37 | memset(res, 0, sizeof(*res)); |
| 38 | |
| 39 | res->statuscode = 200; |
| 40 | res->statusmsg = "OK"; |
| 41 | |
| 42 | bufptr = &buf[0]; |
| 43 | |
| 44 | for (pos = 0; pos < *off; pos++) |
| 45 | { |
| 46 | if (!hdrname && (buf[pos] == ':')) |
| 47 | { |
| 48 | buf[pos++] = 0; |
| 49 | |
| 50 | if ((pos < len) && (buf[pos] == ' ')) |
| 51 | pos++; |
| 52 | |
| 53 | if (pos < len) |
| 54 | { |
| 55 | hdrname = bufptr; |
| 56 | bufptr = &buf[pos]; |
| 57 | } |
| 58 | } |
| 59 | |
| 60 | else if ((buf[pos] == '\r') || (buf[pos] == '\n')) |
| 61 | { |
| 62 | if (! hdrname) |
| 63 | break; |
| 64 | |
| 65 | buf[pos++] = 0; |
| 66 | |
| 67 | if ((pos < len) && (buf[pos] == '\n')) |
| 68 | pos++; |
| 69 | |
| 70 | if (pos <= len) |
| 71 | { |
| 72 | if ((hdrcount+1) < array_size(res->headers)) |
| 73 | { |
| 74 | if (!strcasecmp(hdrname, "Status")) |
| 75 | { |
| 76 | res->statuscode = atoi(bufptr); |
| 77 | |
| 78 | if (res->statuscode < 100) |
| 79 | res->statuscode = 200; |
| 80 | |
| 81 | if (((bufptr = strchr(bufptr, ' ')) != NULL) && |
| 82 | (&bufptr[1] != 0)) |
| 83 | { |
| 84 | res->statusmsg = &bufptr[1]; |
| 85 | } |
| 86 | |
| 87 | D("CGI: HTTP/1.x %03d %s\n", |
| 88 | res->statuscode, res->statusmsg); |
| 89 | } |
| 90 | else |
| 91 | { |
| 92 | D("CGI: HTTP: %s: %s\n", hdrname, bufptr); |
| 93 | |
| 94 | res->headers[hdrcount++] = hdrname; |
| 95 | res->headers[hdrcount++] = bufptr; |
| 96 | } |
| 97 | |
| 98 | bufptr = &buf[pos]; |
| 99 | hdrname = NULL; |
| 100 | } |
| 101 | else |
| 102 | { |
| 103 | return false; |
| 104 | } |
| 105 | } |
| 106 | } |
| 107 | } |
| 108 | |
| 109 | return true; |
| 110 | } |
| 111 | |
| 112 | return false; |
| 113 | } |
| 114 | |
| 115 | static char * uh_cgi_header_lookup(struct http_response *res, |
| 116 | const char *hdrname) |
| 117 | { |
| 118 | int i; |
| 119 | |
| 120 | foreach_header(i, res->headers) |
| 121 | { |
| 122 | if (!strcasecmp(res->headers[i], hdrname)) |
| 123 | return res->headers[i+1]; |
| 124 | } |
| 125 | |
| 126 | return NULL; |
| 127 | } |
| 128 | |
| 129 | static void uh_cgi_shutdown(struct uh_cgi_state *state) |
| 130 | { |
| 131 | free(state); |
| 132 | } |
| 133 | |
| 134 | static bool uh_cgi_socket_cb(struct client *cl) |
| 135 | { |
| 136 | int i, len, blen, hdroff; |
| 137 | char buf[UH_LIMIT_MSGHEAD]; |
| 138 | |
| 139 | struct uh_cgi_state *state = (struct uh_cgi_state *)cl->priv; |
| 140 | struct http_response *res = &cl->response; |
| 141 | struct http_request *req = &cl->request; |
| 142 | |
| 143 | /* there is unread post data waiting */ |
| 144 | while (state->content_length > 0) |
| 145 | { |
| 146 | /* remaining data in http head buffer ... */ |
| 147 | if (cl->httpbuf.len > 0) |
| 148 | { |
| 149 | len = min(state->content_length, cl->httpbuf.len); |
| 150 | |
| 151 | D("CGI: Child(%d) feed %d HTTP buffer bytes\n", cl->proc.pid, len); |
| 152 | |
| 153 | memcpy(buf, cl->httpbuf.ptr, len); |
| 154 | |
| 155 | cl->httpbuf.len -= len; |
| 156 | cl->httpbuf.ptr +=len; |
| 157 | } |
| 158 | |
| 159 | /* read it from socket ... */ |
| 160 | else |
| 161 | { |
| 162 | len = uh_tcp_recv(cl, buf, |
| 163 | min(state->content_length, sizeof(buf))); |
| 164 | |
| 165 | if ((len < 0) && ((errno == EAGAIN) || (errno == EWOULDBLOCK))) |
| 166 | break; |
| 167 | |
| 168 | D("CGI: Child(%d) feed %d/%d TCP socket bytes\n", |
| 169 | cl->proc.pid, len, min(state->content_length, sizeof(buf))); |
| 170 | } |
| 171 | |
| 172 | if (len) |
| 173 | state->content_length -= len; |
| 174 | else |
| 175 | state->content_length = 0; |
| 176 | |
| 177 | /* ... write to CGI process */ |
| 178 | len = uh_raw_send(cl->wpipe.fd, buf, len, |
| 179 | cl->server->conf->script_timeout); |
| 180 | |
| 181 | /* explicit EOF notification for the child */ |
| 182 | if (state->content_length <= 0) |
| 183 | uh_ufd_remove(&cl->wpipe); |
| 184 | } |
| 185 | |
| 186 | /* try to read data from child */ |
| 187 | while ((len = uh_raw_recv(cl->rpipe.fd, buf, state->header_sent |
| 188 | ? sizeof(buf) : state->httpbuf.len, -1)) > 0) |
| 189 | { |
| 190 | /* we have not pushed out headers yet, parse input */ |
| 191 | if (!state->header_sent) |
| 192 | { |
| 193 | /* try to parse header ... */ |
| 194 | memcpy(state->httpbuf.ptr, buf, len); |
| 195 | state->httpbuf.len -= len; |
| 196 | state->httpbuf.ptr += len; |
| 197 | |
| 198 | blen = state->httpbuf.ptr - state->httpbuf.buf; |
| 199 | |
| 200 | if (uh_cgi_header_parse(res, state->httpbuf.buf, blen, &hdroff)) |
| 201 | { |
| 202 | /* write status */ |
| 203 | ensure_out(uh_http_sendf(cl, NULL, |
| 204 | "%s %03d %s\r\n" |
| 205 | "Connection: close\r\n", |
| 206 | http_versions[req->version], |
| 207 | res->statuscode, res->statusmsg)); |
| 208 | |
| 209 | /* add Content-Type if no Location or Content-Type */ |
| 210 | if (!uh_cgi_header_lookup(res, "Location") && |
| 211 | !uh_cgi_header_lookup(res, "Content-Type")) |
| 212 | { |
| 213 | ensure_out(uh_http_send(cl, NULL, |
| 214 | "Content-Type: text/plain\r\n", -1)); |
| 215 | } |
| 216 | |
| 217 | /* if request was HTTP 1.1 we'll respond chunked */ |
| 218 | if ((req->version > UH_HTTP_VER_1_0) && |
| 219 | !uh_cgi_header_lookup(res, "Transfer-Encoding")) |
| 220 | { |
| 221 | ensure_out(uh_http_send(cl, NULL, |
| 222 | "Transfer-Encoding: chunked\r\n", -1)); |
| 223 | } |
| 224 | |
| 225 | /* write headers from CGI program */ |
| 226 | foreach_header(i, res->headers) |
| 227 | { |
| 228 | ensure_out(uh_http_sendf(cl, NULL, "%s: %s\r\n", |
| 229 | res->headers[i], res->headers[i+1])); |
| 230 | } |
| 231 | |
| 232 | /* terminate header */ |
| 233 | ensure_out(uh_http_send(cl, NULL, "\r\n", -1)); |
| 234 | |
| 235 | state->header_sent = true; |
| 236 | |
| 237 | /* push out remaining head buffer */ |
| 238 | if (hdroff < blen) |
| 239 | { |
| 240 | D("CGI: Child(%d) relaying %d rest bytes\n", |
| 241 | cl->proc.pid, blen - hdroff); |
| 242 | |
| 243 | ensure_out(uh_http_send(cl, req, |
| 244 | state->httpbuf.buf + hdroff, |
| 245 | blen - hdroff)); |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | /* ... failed and head buffer exceeded */ |
| 250 | else if (!state->httpbuf.len) |
| 251 | { |
| 252 | /* I would do this ... |
| 253 | * |
| 254 | * uh_cgi_error_500(cl, req, |
| 255 | * "The CGI program generated an " |
| 256 | * "invalid response:\n\n"); |
| 257 | * |
| 258 | * ... but in order to stay as compatible as possible, |
| 259 | * treat whatever we got as text/plain response and |
| 260 | * build the required headers here. |
| 261 | */ |
| 262 | |
| 263 | ensure_out(uh_http_sendf(cl, NULL, |
| 264 | "%s 200 OK\r\n" |
| 265 | "Content-Type: text/plain\r\n" |
| 266 | "%s\r\n", |
| 267 | http_versions[req->version], |
| 268 | (req->version > UH_HTTP_VER_1_0) |
| 269 | ? "Transfer-Encoding: chunked\r\n" : "" |
| 270 | )); |
| 271 | |
| 272 | state->header_sent = true; |
| 273 | |
| 274 | D("CGI: Child(%d) relaying %d invalid bytes\n", |
| 275 | cl->proc.pid, len); |
| 276 | |
| 277 | ensure_out(uh_http_send(cl, req, buf, len)); |
| 278 | } |
| 279 | } |
| 280 | else |
| 281 | { |
| 282 | /* headers complete, pass through buffer to socket */ |
| 283 | D("CGI: Child(%d) relaying %d normal bytes\n", cl->proc.pid, len); |
| 284 | ensure_out(uh_http_send(cl, req, buf, len)); |
| 285 | } |
| 286 | } |
| 287 | |
| 288 | /* got EOF or read error from child */ |
| 289 | if ((len == 0) || |
| 290 | ((errno != EAGAIN) && (errno != EWOULDBLOCK) && (len == -1))) |
| 291 | { |
| 292 | D("CGI: Child(%d) presumed dead [%s]\n", cl->proc.pid, strerror(errno)); |
| 293 | |
| 294 | goto out; |
| 295 | } |
| 296 | |
| 297 | return true; |
| 298 | |
| 299 | out: |
| 300 | if (!state->header_sent) |
| 301 | { |
| 302 | if (cl->timeout.pending) |
| 303 | uh_http_sendhf(cl, 502, "Bad Gateway", |
| 304 | "The CGI process did not produce any response\n"); |
| 305 | else |
| 306 | uh_http_sendhf(cl, 504, "Gateway Timeout", |
| 307 | "The CGI process took too long to produce a " |
| 308 | "response\n"); |
| 309 | } |
| 310 | else |
| 311 | { |
| 312 | uh_http_send(cl, req, "", 0); |
| 313 | } |
| 314 | |
| 315 | uh_cgi_shutdown(state); |
| 316 | return false; |
| 317 | } |
| 318 | |
| 319 | bool uh_cgi_request(struct client *cl, struct path_info *pi, |
| 320 | struct interpreter *ip) |
| 321 | { |
| 322 | int i; |
| 323 | |
| 324 | int rfd[2] = { 0, 0 }; |
| 325 | int wfd[2] = { 0, 0 }; |
| 326 | |
| 327 | pid_t child; |
| 328 | |
| 329 | struct uh_cgi_state *state; |
| 330 | struct http_request *req = &cl->request; |
| 331 | |
| 332 | /* allocate state */ |
| 333 | if (!(state = malloc(sizeof(*state)))) |
| 334 | { |
| 335 | uh_http_sendhf(cl, 500, "Internal Server Error", "Out of memory"); |
| 336 | return false; |
| 337 | } |
| 338 | |
| 339 | /* spawn pipes for me->child, child->me */ |
| 340 | if ((pipe(rfd) < 0) || (pipe(wfd) < 0)) |
| 341 | { |
| 342 | if (rfd[0] > 0) close(rfd[0]); |
| 343 | if (rfd[1] > 0) close(rfd[1]); |
| 344 | if (wfd[0] > 0) close(wfd[0]); |
| 345 | if (wfd[1] > 0) close(wfd[1]); |
| 346 | |
| 347 | uh_http_sendhf(cl, 500, "Internal Server Error", |
| 348 | "Failed to create pipe: %s\n", strerror(errno)); |
| 349 | |
| 350 | return false; |
| 351 | } |
| 352 | |
| 353 | /* fork off child process */ |
| 354 | switch ((child = fork())) |
| 355 | { |
| 356 | /* oops */ |
| 357 | case -1: |
| 358 | uh_http_sendhf(cl, 500, "Internal Server Error", |
| 359 | "Failed to fork child: %s\n", strerror(errno)); |
| 360 | |
| 361 | return false; |
| 362 | |
| 363 | /* exec child */ |
| 364 | case 0: |
| 365 | #ifdef DEBUG |
| 366 | sleep(atoi(getenv("UHTTPD_SLEEP_ON_FORK") ?: "0")); |
| 367 | #endif |
| 368 | |
| 369 | /* do not leak parent epoll descriptor */ |
| 370 | uloop_done(); |
| 371 | |
| 372 | /* close loose pipe ends */ |
| 373 | close(rfd[0]); |
| 374 | close(wfd[1]); |
| 375 | |
| 376 | /* patch stdout and stdin to pipes */ |
| 377 | dup2(rfd[1], 1); |
| 378 | dup2(wfd[0], 0); |
| 379 | |
| 380 | /* avoid leaking our pipe into child-child processes */ |
| 381 | fd_cloexec(rfd[1]); |
| 382 | fd_cloexec(wfd[0]); |
| 383 | |
| 384 | /* check for regular, world-executable file _or_ interpreter */ |
| 385 | if (((pi->stat.st_mode & S_IFREG) && |
| 386 | (pi->stat.st_mode & S_IXOTH)) || (ip != NULL)) |
| 387 | { |
| 388 | /* build environment */ |
| 389 | clearenv(); |
| 390 | |
| 391 | /* common information */ |
| 392 | setenv("GATEWAY_INTERFACE", "CGI/1.1", 1); |
| 393 | setenv("SERVER_SOFTWARE", "uHTTPd", 1); |
| 394 | setenv("PATH", "/sbin:/usr/sbin:/bin:/usr/bin", 1); |
| 395 | |
| 396 | #ifdef HAVE_TLS |
| 397 | /* https? */ |
| 398 | if (cl->tls) |
| 399 | setenv("HTTPS", "on", 1); |
| 400 | #endif |
| 401 | |
| 402 | /* addresses */ |
| 403 | setenv("SERVER_NAME", sa_straddr(&cl->servaddr), 1); |
| 404 | setenv("SERVER_ADDR", sa_straddr(&cl->servaddr), 1); |
| 405 | setenv("SERVER_PORT", sa_strport(&cl->servaddr), 1); |
| 406 | setenv("REMOTE_HOST", sa_straddr(&cl->peeraddr), 1); |
| 407 | setenv("REMOTE_ADDR", sa_straddr(&cl->peeraddr), 1); |
| 408 | setenv("REMOTE_PORT", sa_strport(&cl->peeraddr), 1); |
| 409 | |
| 410 | /* path information */ |
| 411 | setenv("SCRIPT_NAME", pi->name, 1); |
| 412 | setenv("SCRIPT_FILENAME", pi->phys, 1); |
| 413 | setenv("DOCUMENT_ROOT", pi->root, 1); |
| 414 | setenv("QUERY_STRING", pi->query ? pi->query : "", 1); |
| 415 | |
| 416 | if (pi->info) |
| 417 | setenv("PATH_INFO", pi->info, 1); |
| 418 | |
| 419 | /* REDIRECT_STATUS, php-cgi wants it */ |
| 420 | switch (req->redirect_status) |
| 421 | { |
| 422 | case 404: |
| 423 | setenv("REDIRECT_STATUS", "404", 1); |
| 424 | break; |
| 425 | |
| 426 | default: |
| 427 | setenv("REDIRECT_STATUS", "200", 1); |
| 428 | break; |
| 429 | } |
| 430 | |
| 431 | /* http version */ |
| 432 | setenv("SERVER_PROTOCOL", http_versions[req->version], 1); |
| 433 | |
| 434 | /* request method */ |
| 435 | setenv("REQUEST_METHOD", http_methods[req->method], 1); |
| 436 | |
| 437 | /* request url */ |
| 438 | setenv("REQUEST_URI", req->url, 1); |
| 439 | |
| 440 | /* remote user */ |
| 441 | if (req->realm) |
| 442 | setenv("REMOTE_USER", req->realm->user, 1); |
| 443 | |
| 444 | /* request message headers */ |
| 445 | foreach_header(i, req->headers) |
| 446 | { |
| 447 | if (!strcasecmp(req->headers[i], "Accept")) |
| 448 | setenv("HTTP_ACCEPT", req->headers[i+1], 1); |
| 449 | |
| 450 | else if (!strcasecmp(req->headers[i], "Accept-Charset")) |
| 451 | setenv("HTTP_ACCEPT_CHARSET", req->headers[i+1], 1); |
| 452 | |
| 453 | else if (!strcasecmp(req->headers[i], "Accept-Encoding")) |
| 454 | setenv("HTTP_ACCEPT_ENCODING", req->headers[i+1], 1); |
| 455 | |
| 456 | else if (!strcasecmp(req->headers[i], "Accept-Language")) |
| 457 | setenv("HTTP_ACCEPT_LANGUAGE", req->headers[i+1], 1); |
| 458 | |
| 459 | else if (!strcasecmp(req->headers[i], "Authorization")) |
| 460 | setenv("HTTP_AUTHORIZATION", req->headers[i+1], 1); |
| 461 | |
| 462 | else if (!strcasecmp(req->headers[i], "Connection")) |
| 463 | setenv("HTTP_CONNECTION", req->headers[i+1], 1); |
| 464 | |
| 465 | else if (!strcasecmp(req->headers[i], "Cookie")) |
| 466 | setenv("HTTP_COOKIE", req->headers[i+1], 1); |
| 467 | |
| 468 | else if (!strcasecmp(req->headers[i], "Host")) |
| 469 | setenv("HTTP_HOST", req->headers[i+1], 1); |
| 470 | |
| 471 | else if (!strcasecmp(req->headers[i], "Referer")) |
| 472 | setenv("HTTP_REFERER", req->headers[i+1], 1); |
| 473 | |
| 474 | else if (!strcasecmp(req->headers[i], "User-Agent")) |
| 475 | setenv("HTTP_USER_AGENT", req->headers[i+1], 1); |
| 476 | |
| 477 | else if (!strcasecmp(req->headers[i], "Content-Type")) |
| 478 | setenv("CONTENT_TYPE", req->headers[i+1], 1); |
| 479 | |
| 480 | else if (!strcasecmp(req->headers[i], "Content-Length")) |
| 481 | setenv("CONTENT_LENGTH", req->headers[i+1], 1); |
| 482 | } |
| 483 | |
| 484 | |
| 485 | /* execute child code ... */ |
| 486 | if (chdir(pi->root)) |
| 487 | perror("chdir()"); |
| 488 | |
| 489 | if (ip != NULL) |
| 490 | execl(ip->path, ip->path, pi->phys, NULL); |
| 491 | else |
| 492 | execl(pi->phys, pi->phys, NULL); |
| 493 | |
| 494 | /* in case it fails ... */ |
| 495 | printf("Status: 500 Internal Server Error\r\n\r\n" |
| 496 | "Unable to launch the requested CGI program:\n" |
| 497 | " %s: %s\n", ip ? ip->path : pi->phys, strerror(errno)); |
| 498 | } |
| 499 | |
| 500 | /* 403 */ |
| 501 | else |
| 502 | { |
| 503 | printf("Status: 403 Forbidden\r\n\r\n" |
| 504 | "Access to this resource is forbidden\n"); |
| 505 | } |
| 506 | |
| 507 | close(wfd[0]); |
| 508 | close(rfd[1]); |
| 509 | exit(0); |
| 510 | |
| 511 | break; |
| 512 | |
| 513 | /* parent; handle I/O relaying */ |
| 514 | default: |
| 515 | memset(state, 0, sizeof(*state)); |
| 516 | |
| 517 | cl->rpipe.fd = rfd[0]; |
| 518 | cl->wpipe.fd = wfd[1]; |
| 519 | cl->proc.pid = child; |
| 520 | |
| 521 | /* make pipe non-blocking */ |
| 522 | fd_nonblock(cl->rpipe.fd); |
| 523 | fd_nonblock(cl->wpipe.fd); |
| 524 | |
| 525 | /* close unneeded pipe ends */ |
| 526 | close(rfd[1]); |
| 527 | close(wfd[0]); |
| 528 | |
| 529 | D("CGI: Child(%d) created: rfd(%d) wfd(%d)\n", child, rfd[0], wfd[1]); |
| 530 | |
| 531 | state->httpbuf.ptr = state->httpbuf.buf; |
| 532 | state->httpbuf.len = sizeof(state->httpbuf.buf); |
| 533 | |
| 534 | state->content_length = cl->httpbuf.len; |
| 535 | |
| 536 | /* find content length */ |
| 537 | if (req->method == UH_HTTP_MSG_POST) |
| 538 | { |
| 539 | foreach_header(i, req->headers) |
| 540 | { |
| 541 | if (!strcasecmp(req->headers[i], "Content-Length")) |
| 542 | { |
| 543 | state->content_length = atoi(req->headers[i+1]); |
| 544 | break; |
| 545 | } |
| 546 | } |
| 547 | } |
| 548 | |
| 549 | cl->cb = uh_cgi_socket_cb; |
| 550 | cl->priv = state; |
| 551 | |
| 552 | break; |
| 553 | } |
| 554 | |
| 555 | return true; |
| 556 | } |
| 557 | |
