package/uhttpd/src/uhttpd-cgi.c

   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         close(state->rfd);
 132         close(state->wfd);
 133         free(state);
 134 }
 135
 136 static bool uh_cgi_socket_cb(struct client *cl)
 137 {
 138         int i, len, hdroff;
 139         char buf[UH_LIMIT_MSGHEAD];
 140
 141         struct uh_cgi_state *state = (struct uh_cgi_state *)cl->priv;
 142         struct http_response *res = &state->cl->response;
 143         struct http_request *req = &state->cl->request;
 144
 145         /* there is unread post data waiting */
 146         while (state->content_length > 0)
 147         {
 148                 /* remaining data in http head buffer ... */
 149                 if (state->cl->httpbuf.len > 0)
 150                 {
 151                         len = min(state->content_length, state->cl->httpbuf.len);
 152
 153                         D("CGI: Child(%d) feed %d HTTP buffer bytes\n",
 154                           state->cl->proc.pid, len);
 155
 156                         memcpy(buf, state->cl->httpbuf.ptr, len);
 157
 158                         state->cl->httpbuf.len -= len;
 159                         state->cl->httpbuf.ptr +=len;
 160                 }
 161
 162                 /* read it from socket ... */
 163                 else
 164                 {
 165                         len = uh_tcp_recv(state->cl, buf,
 166                                                           min(state->content_length, sizeof(buf)));
 167
 168                         if ((len < 0) && ((errno == EAGAIN) || (errno == EWOULDBLOCK)))
 169                                 break;
 170
 171                         D("CGI: Child(%d) feed %d/%d TCP socket bytes\n",
 172                           state->cl->proc.pid, len,
 173                           min(state->content_length, sizeof(buf)));
 174                 }
 175
 176                 if (len)
 177                         state->content_length -= len;
 178                 else
 179                         state->content_length = 0;
 180
 181                 /* ... write to CGI process */
 182                 len = uh_raw_send(state->wfd, buf, len,
 183                                                   cl->server->conf->script_timeout);
 184         }
 185
 186         /* try to read data from child */
 187         while ((len = uh_raw_recv(state->rfd, buf, sizeof(buf), -1)) > 0)
 188         {
 189                 /* we have not pushed out headers yet, parse input */
 190                 if (!state->header_sent)
 191                 {
 192                         /* try to parse header ... */
 193                         memcpy(state->httpbuf, buf, len);
 194
 195                         if (uh_cgi_header_parse(res, state->httpbuf, len, &hdroff))
 196                         {
 197                                 /* write status */
 198                                 ensure_out(uh_http_sendf(state->cl, NULL,
 199                                         "HTTP/%.1f %03d %s\r\n"
 200                                         "Connection: close\r\n",
 201                                         req->version, res->statuscode, res->statusmsg));
 202
 203                                 /* add Content-Type if no Location or Content-Type */
 204                                 if (!uh_cgi_header_lookup(res, "Location") &&
 205                                         !uh_cgi_header_lookup(res, "Content-Type"))
 206                                 {
 207                                         ensure_out(uh_http_send(state->cl, NULL,
 208                                                 "Content-Type: text/plain\r\n", -1));
 209                                 }
 210
 211                                 /* if request was HTTP 1.1 we'll respond chunked */
 212                                 if ((req->version > 1.0) &&
 213                                         !uh_cgi_header_lookup(res, "Transfer-Encoding"))
 214                                 {
 215                                         ensure_out(uh_http_send(state->cl, NULL,
 216                                                 "Transfer-Encoding: chunked\r\n", -1));
 217                                 }
 218
 219                                 /* write headers from CGI program */
 220                                 foreach_header(i, res->headers)
 221                                 {
 222                                         ensure_out(uh_http_sendf(state->cl, NULL, "%s: %s\r\n",
 223                                                 res->headers[i], res->headers[i+1]));
 224                                 }
 225
 226                                 /* terminate header */
 227                                 ensure_out(uh_http_send(state->cl, NULL, "\r\n", -1));
 228
 229                                 state->header_sent = true;
 230
 231                                 /* push out remaining head buffer */
 232                                 if (hdroff < len)
 233                                 {
 234                                         D("CGI: Child(%d) relaying %d rest bytes\n",
 235                                           state->cl->proc.pid, len - hdroff);
 236
 237                                         ensure_out(uh_http_send(state->cl, req,
 238                                                                                         &buf[hdroff], len - hdroff));
 239                                 }
 240                         }
 241
 242                         /* ... failed and head buffer exceeded */
 243                         else
 244                         {
 245                                 /* I would do this ...
 246                                  *
 247                                  *    uh_cgi_error_500(cl, req,
 248                                  *        "The CGI program generated an "
 249                                  *        "invalid response:\n\n");
 250                                  *
 251                                  * ... but in order to stay as compatible as possible,
 252                                  * treat whatever we got as text/plain response and
 253                                  * build the required headers here.
 254                                  */
 255
 256                                 ensure_out(uh_http_sendf(state->cl, NULL,
 257                                                                                  "HTTP/%.1f 200 OK\r\n"
 258                                                                                  "Content-Type: text/plain\r\n"
 259                                                                                  "%s\r\n",
 260                                                                                  req->version, (req->version > 1.0)
 261                                                                                  ? "Transfer-Encoding: chunked\r\n" : ""
 262                                 ));
 263
 264                                 state->header_sent = true;
 265
 266                                 D("CGI: Child(%d) relaying %d invalid bytes\n",
 267                                   state->cl->proc.pid, len);
 268
 269                                 ensure_out(uh_http_send(state->cl, req, buf, len));
 270                         }
 271                 }
 272                 else
 273                 {
 274                         /* headers complete, pass through buffer to socket */
 275                         D("CGI: Child(%d) relaying %d normal bytes\n",
 276                           state->cl->proc.pid, len);
 277
 278                         ensure_out(uh_http_send(state->cl, req, buf, len));
 279                 }
 280         }
 281
 282         /* child has been marked dead by timeout or child handler, bail out */
 283         if (false && cl->dead)
 284         {
 285                 D("CGI: Child(%d) is marked dead, returning\n", state->cl->proc.pid);
 286                 goto out;
 287         }
 288
 289         if ((len == 0) ||
 290                 ((errno != EAGAIN) && (errno != EWOULDBLOCK) && (len == -1)))
 291         {
 292                 D("CGI: Child(%d) presumed dead [%s]\n",
 293                   state->cl->proc.pid, strerror(errno));
 294
 295                 goto out;
 296         }
 297
 298         return true;
 299
 300 out:
 301         if (!state->header_sent)
 302         {
 303                 if (state->cl->timeout.pending)
 304                         uh_http_sendhf(state->cl, 502, "Bad Gateway",
 305                                                    "The CGI process did not produce any response\n");
 306                 else
 307                         uh_http_sendhf(state->cl, 504, "Gateway Timeout",
 308                                                    "The CGI process took too long to produce a "
 309                                                    "response\n");
 310         }
 311         else
 312         {
 313                 uh_http_send(state->cl, req, "", 0);
 314         }
 315
 316         uh_cgi_shutdown(state);
 317         return false;
 318 }
 319
 320 bool uh_cgi_request(struct client *cl, struct path_info *pi,
 321                                         struct interpreter *ip)
 322 {
 323         int i;
 324
 325         int rfd[2] = { 0, 0 };
 326         int wfd[2] = { 0, 0 };
 327
 328         pid_t child;
 329
 330         struct uh_cgi_state *state;
 331         struct http_request *req = &cl->request;
 332
 333         /* allocate state */
 334         if (!(state = malloc(sizeof(*state))))
 335         {
 336                 uh_http_sendhf(cl, 500, "Internal Server Error", "Out of memory");
 337                 return false;
 338         }
 339
 340         /* spawn pipes for me->child, child->me */
 341         if ((pipe(rfd) < 0) || (pipe(wfd) < 0))
 342         {
 343                 if (rfd[0] > 0) close(rfd[0]);
 344                 if (rfd[1] > 0) close(rfd[1]);
 345                 if (wfd[0] > 0) close(wfd[0]);
 346                 if (wfd[1] > 0) close(wfd[1]);
 347
 348                 uh_http_sendhf(cl, 500, "Internal Server Error",
 349                                                 "Failed to create pipe: %s\n", strerror(errno));
 350
 351                 return false;
 352         }
 353
 354         /* fork off child process */
 355         switch ((child = fork()))
 356         {
 357         /* oops */
 358         case -1:
 359                 uh_http_sendhf(cl, 500, "Internal Server Error",
 360                                                 "Failed to fork child: %s\n", strerror(errno));
 361
 362                 return false;
 363
 364         /* exec child */
 365         case 0:
 366 #ifdef DEBUG
 367                 sleep(atoi(getenv("UHTTPD_SLEEP_ON_FORK") ?: "0"));
 368 #endif
 369
 370                 /* close loose pipe ends */
 371                 close(rfd[0]);
 372                 close(wfd[1]);
 373
 374                 /* patch stdout and stdin to pipes */
 375                 dup2(rfd[1], 1);
 376                 dup2(wfd[0], 0);
 377
 378                 /* avoid leaking our pipe into child-child processes */
 379                 fd_cloexec(rfd[1]);
 380                 fd_cloexec(wfd[0]);
 381
 382                 /* check for regular, world-executable file _or_ interpreter */
 383                 if (((pi->stat.st_mode & S_IFREG) &&
 384                          (pi->stat.st_mode & S_IXOTH)) || (ip != NULL))
 385                 {
 386                         /* build environment */
 387                         clearenv();
 388
 389                         /* common information */
 390                         setenv("GATEWAY_INTERFACE", "CGI/1.1", 1);
 391                         setenv("SERVER_SOFTWARE", "uHTTPd", 1);
 392                         setenv("PATH", "/sbin:/usr/sbin:/bin:/usr/bin", 1);
 393
 394 #ifdef HAVE_TLS
 395                         /* https? */
 396                         if (cl->tls)
 397                                 setenv("HTTPS", "on", 1);
 398 #endif
 399
 400                         /* addresses */
 401                         setenv("SERVER_NAME", sa_straddr(&cl->servaddr), 1);
 402                         setenv("SERVER_ADDR", sa_straddr(&cl->servaddr), 1);
 403                         setenv("SERVER_PORT", sa_strport(&cl->servaddr), 1);
 404                         setenv("REMOTE_HOST", sa_straddr(&cl->peeraddr), 1);
 405                         setenv("REMOTE_ADDR", sa_straddr(&cl->peeraddr), 1);
 406                         setenv("REMOTE_PORT", sa_strport(&cl->peeraddr), 1);
 407
 408                         /* path information */
 409                         setenv("SCRIPT_NAME", pi->name, 1);
 410                         setenv("SCRIPT_FILENAME", pi->phys, 1);
 411                         setenv("DOCUMENT_ROOT", pi->root, 1);
 412                         setenv("QUERY_STRING", pi->query ? pi->query : "", 1);
 413
 414                         if (pi->info)
 415                                 setenv("PATH_INFO", pi->info, 1);
 416
 417                         /* REDIRECT_STATUS, php-cgi wants it */
 418                         switch (req->redirect_status)
 419                         {
 420                                 case 404:
 421                                         setenv("REDIRECT_STATUS", "404", 1);
 422                                         break;
 423
 424                                 default:
 425                                         setenv("REDIRECT_STATUS", "200", 1);
 426                                         break;
 427                         }
 428
 429                         /* http version */
 430                         if (req->version > 1.0)
 431                                 setenv("SERVER_PROTOCOL", "HTTP/1.1", 1);
 432                         else
 433                                 setenv("SERVER_PROTOCOL", "HTTP/1.0", 1);
 434
 435                         /* request method */
 436                         switch (req->method)
 437                         {
 438                                 case UH_HTTP_MSG_GET:
 439                                         setenv("REQUEST_METHOD", "GET", 1);
 440                                         break;
 441
 442                                 case UH_HTTP_MSG_HEAD:
 443                                         setenv("REQUEST_METHOD", "HEAD", 1);
 444                                         break;
 445
 446                                 case UH_HTTP_MSG_POST:
 447                                         setenv("REQUEST_METHOD", "POST", 1);
 448                                         break;
 449                         }
 450
 451                         /* request url */
 452                         setenv("REQUEST_URI", req->url, 1);
 453
 454                         /* remote user */
 455                         if (req->realm)
 456                                 setenv("REMOTE_USER", req->realm->user, 1);
 457
 458                         /* request message headers */
 459                         foreach_header(i, req->headers)
 460                         {
 461                                 if (!strcasecmp(req->headers[i], "Accept"))
 462                                         setenv("HTTP_ACCEPT", req->headers[i+1], 1);
 463
 464                                 else if (!strcasecmp(req->headers[i], "Accept-Charset"))
 465                                         setenv("HTTP_ACCEPT_CHARSET", req->headers[i+1], 1);
 466
 467                                 else if (!strcasecmp(req->headers[i], "Accept-Encoding"))
 468                                         setenv("HTTP_ACCEPT_ENCODING", req->headers[i+1], 1);
 469
 470                                 else if (!strcasecmp(req->headers[i], "Accept-Language"))
 471                                         setenv("HTTP_ACCEPT_LANGUAGE", req->headers[i+1], 1);
 472
 473                                 else if (!strcasecmp(req->headers[i], "Authorization"))
 474                                         setenv("HTTP_AUTHORIZATION", req->headers[i+1], 1);
 475
 476                                 else if (!strcasecmp(req->headers[i], "Connection"))
 477                                         setenv("HTTP_CONNECTION", req->headers[i+1], 1);
 478
 479                                 else if (!strcasecmp(req->headers[i], "Cookie"))
 480                                         setenv("HTTP_COOKIE", req->headers[i+1], 1);
 481
 482                                 else if (!strcasecmp(req->headers[i], "Host"))
 483                                         setenv("HTTP_HOST", req->headers[i+1], 1);
 484
 485                                 else if (!strcasecmp(req->headers[i], "Referer"))
 486                                         setenv("HTTP_REFERER", req->headers[i+1], 1);
 487
 488                                 else if (!strcasecmp(req->headers[i], "User-Agent"))
 489                                         setenv("HTTP_USER_AGENT", req->headers[i+1], 1);
 490
 491                                 else if (!strcasecmp(req->headers[i], "Content-Type"))
 492                                         setenv("CONTENT_TYPE", req->headers[i+1], 1);
 493
 494                                 else if (!strcasecmp(req->headers[i], "Content-Length"))
 495                                         setenv("CONTENT_LENGTH", req->headers[i+1], 1);
 496                         }
 497
 498
 499                         /* execute child code ... */
 500                         if (chdir(pi->root))
 501                                 perror("chdir()");
 502
 503                         if (ip != NULL)
 504                                 execl(ip->path, ip->path, pi->phys, NULL);
 505                         else
 506                                 execl(pi->phys, pi->phys, NULL);
 507
 508                         /* in case it fails ... */
 509                         printf("Status: 500 Internal Server Error\r\n\r\n"
 510                                    "Unable to launch the requested CGI program:\n"
 511                                    "  %s: %s\n", ip ? ip->path : pi->phys, strerror(errno));
 512                 }
 513
 514                 /* 403 */
 515                 else
 516                 {
 517                         printf("Status: 403 Forbidden\r\n\r\n"
 518                                    "Access to this resource is forbidden\n");
 519                 }
 520
 521                 close(wfd[0]);
 522                 close(rfd[1]);
 523                 exit(0);
 524
 525                 break;
 526
 527         /* parent; handle I/O relaying */
 528         default:
 529                 memset(state, 0, sizeof(*state));
 530
 531                 state->cl = cl;
 532                 state->cl->proc.pid = child;
 533
 534                 /* close unneeded pipe ends */
 535                 close(rfd[1]);
 536                 close(wfd[0]);
 537
 538                 D("CGI: Child(%d) created: rfd(%d) wfd(%d)\n", child, rfd[0], wfd[1]);
 539
 540                 state->content_length = cl->httpbuf.len;
 541
 542                 /* find content length */
 543                 if (req->method == UH_HTTP_MSG_POST)
 544                 {
 545                         foreach_header(i, req->headers)
 546                         {
 547                                 if (!strcasecmp(req->headers[i], "Content-Length"))
 548                                 {
 549                                         state->content_length = atoi(req->headers[i+1]);
 550                                         break;
 551                                 }
 552                         }
 553                 }
 554
 555                 state->rfd = rfd[0];
 556                 fd_nonblock(state->rfd);
 557
 558                 state->wfd = wfd[1];
 559                 fd_nonblock(state->wfd);
 560
 561                 cl->cb = uh_cgi_socket_cb;
 562                 cl->priv = state;
 563
 564                 break;
 565         }
 566
 567         return true;
 568 }