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                 /* explicit EOF notification for the child */
 186                 if (state->content_length <= 0)
 187                         close(state->wfd);
 188         }
 189
 190         /* try to read data from child */
 191         while ((len = uh_raw_recv(state->rfd, buf, sizeof(buf), -1)) > 0)
 192         {
 193                 /* we have not pushed out headers yet, parse input */
 194                 if (!state->header_sent)
 195                 {
 196                         /* try to parse header ... */
 197                         memcpy(state->httpbuf, buf, len);
 198
 199                         if (uh_cgi_header_parse(res, state->httpbuf, len, &hdroff))
 200                         {
 201                                 /* write status */
 202                                 ensure_out(uh_http_sendf(state->cl, NULL,
 203                                         "HTTP/%.1f %03d %s\r\n"
 204                                         "Connection: close\r\n",
 205                                         req->version, res->statuscode, res->statusmsg));
 206
 207                                 /* add Content-Type if no Location or Content-Type */
 208                                 if (!uh_cgi_header_lookup(res, "Location") &&
 209                                         !uh_cgi_header_lookup(res, "Content-Type"))
 210                                 {
 211                                         ensure_out(uh_http_send(state->cl, NULL,
 212                                                 "Content-Type: text/plain\r\n", -1));
 213                                 }
 214
 215                                 /* if request was HTTP 1.1 we'll respond chunked */
 216                                 if ((req->version > 1.0) &&
 217                                         !uh_cgi_header_lookup(res, "Transfer-Encoding"))
 218                                 {
 219                                         ensure_out(uh_http_send(state->cl, NULL,
 220                                                 "Transfer-Encoding: chunked\r\n", -1));
 221                                 }
 222
 223                                 /* write headers from CGI program */
 224                                 foreach_header(i, res->headers)
 225                                 {
 226                                         ensure_out(uh_http_sendf(state->cl, NULL, "%s: %s\r\n",
 227                                                 res->headers[i], res->headers[i+1]));
 228                                 }
 229
 230                                 /* terminate header */
 231                                 ensure_out(uh_http_send(state->cl, NULL, "\r\n", -1));
 232
 233                                 state->header_sent = true;
 234
 235                                 /* push out remaining head buffer */
 236                                 if (hdroff < len)
 237                                 {
 238                                         D("CGI: Child(%d) relaying %d rest bytes\n",
 239                                           state->cl->proc.pid, len - hdroff);
 240
 241                                         ensure_out(uh_http_send(state->cl, req,
 242                                                                                         &buf[hdroff], len - hdroff));
 243                                 }
 244                         }
 245
 246                         /* ... failed and head buffer exceeded */
 247                         else
 248                         {
 249                                 /* I would do this ...
 250                                  *
 251                                  *    uh_cgi_error_500(cl, req,
 252                                  *        "The CGI program generated an "
 253                                  *        "invalid response:\n\n");
 254                                  *
 255                                  * ... but in order to stay as compatible as possible,
 256                                  * treat whatever we got as text/plain response and
 257                                  * build the required headers here.
 258                                  */
 259
 260                                 ensure_out(uh_http_sendf(state->cl, NULL,
 261                                                                                  "HTTP/%.1f 200 OK\r\n"
 262                                                                                  "Content-Type: text/plain\r\n"
 263                                                                                  "%s\r\n",
 264                                                                                  req->version, (req->version > 1.0)
 265                                                                                  ? "Transfer-Encoding: chunked\r\n" : ""
 266                                 ));
 267
 268                                 state->header_sent = true;
 269
 270                                 D("CGI: Child(%d) relaying %d invalid bytes\n",
 271                                   state->cl->proc.pid, len);
 272
 273                                 ensure_out(uh_http_send(state->cl, req, buf, len));
 274                         }
 275                 }
 276                 else
 277                 {
 278                         /* headers complete, pass through buffer to socket */
 279                         D("CGI: Child(%d) relaying %d normal bytes\n",
 280                           state->cl->proc.pid, len);
 281
 282                         ensure_out(uh_http_send(state->cl, req, buf, len));
 283                 }
 284         }
 285
 286         /* got EOF or read error from child */
 287         if ((len == 0) ||
 288                 ((errno != EAGAIN) && (errno != EWOULDBLOCK) && (len == -1)))
 289         {
 290                 D("CGI: Child(%d) presumed dead [%s]\n",
 291                   state->cl->proc.pid, strerror(errno));
 292
 293                 goto out;
 294         }
 295
 296         return true;
 297
 298 out:
 299         if (!state->header_sent)
 300         {
 301                 if (state->cl->timeout.pending)
 302                         uh_http_sendhf(state->cl, 502, "Bad Gateway",
 303                                                    "The CGI process did not produce any response\n");
 304                 else
 305                         uh_http_sendhf(state->cl, 504, "Gateway Timeout",
 306                                                    "The CGI process took too long to produce a "
 307                                                    "response\n");
 308         }
 309         else
 310         {
 311                 uh_http_send(state->cl, req, "", 0);
 312         }
 313
 314         uh_cgi_shutdown(state);
 315         return false;
 316 }
 317
 318 bool uh_cgi_request(struct client *cl, struct path_info *pi,
 319                                         struct interpreter *ip)
 320 {
 321         int i;
 322
 323         int rfd[2] = { 0, 0 };
 324         int wfd[2] = { 0, 0 };
 325
 326         pid_t child;
 327
 328         struct uh_cgi_state *state;
 329         struct http_request *req = &cl->request;
 330
 331         /* allocate state */
 332         if (!(state = malloc(sizeof(*state))))
 333         {
 334                 uh_http_sendhf(cl, 500, "Internal Server Error", "Out of memory");
 335                 return false;
 336         }
 337
 338         /* spawn pipes for me->child, child->me */
 339         if ((pipe(rfd) < 0) || (pipe(wfd) < 0))
 340         {
 341                 if (rfd[0] > 0) close(rfd[0]);
 342                 if (rfd[1] > 0) close(rfd[1]);
 343                 if (wfd[0] > 0) close(wfd[0]);
 344                 if (wfd[1] > 0) close(wfd[1]);
 345
 346                 uh_http_sendhf(cl, 500, "Internal Server Error",
 347                                                 "Failed to create pipe: %s\n", strerror(errno));
 348
 349                 return false;
 350         }
 351
 352         /* fork off child process */
 353         switch ((child = fork()))
 354         {
 355         /* oops */
 356         case -1:
 357                 uh_http_sendhf(cl, 500, "Internal Server Error",
 358                                                 "Failed to fork child: %s\n", strerror(errno));
 359
 360                 return false;
 361
 362         /* exec child */
 363         case 0:
 364 #ifdef DEBUG
 365                 sleep(atoi(getenv("UHTTPD_SLEEP_ON_FORK") ?: "0"));
 366 #endif
 367
 368                 /* do not leak parent epoll descriptor */
 369                 uloop_done();
 370
 371                 /* close loose pipe ends */
 372                 close(rfd[0]);
 373                 close(wfd[1]);
 374
 375                 /* patch stdout and stdin to pipes */
 376                 dup2(rfd[1], 1);
 377                 dup2(wfd[0], 0);
 378
 379                 /* avoid leaking our pipe into child-child processes */
 380                 fd_cloexec(rfd[1]);
 381                 fd_cloexec(wfd[0]);
 382
 383                 /* check for regular, world-executable file _or_ interpreter */
 384                 if (((pi->stat.st_mode & S_IFREG) &&
 385                          (pi->stat.st_mode & S_IXOTH)) || (ip != NULL))
 386                 {
 387                         /* build environment */
 388                         clearenv();
 389
 390                         /* common information */
 391                         setenv("GATEWAY_INTERFACE", "CGI/1.1", 1);
 392                         setenv("SERVER_SOFTWARE", "uHTTPd", 1);
 393                         setenv("PATH", "/sbin:/usr/sbin:/bin:/usr/bin", 1);
 394
 395 #ifdef HAVE_TLS
 396                         /* https? */
 397                         if (cl->tls)
 398                                 setenv("HTTPS", "on", 1);
 399 #endif
 400
 401                         /* addresses */
 402                         setenv("SERVER_NAME", sa_straddr(&cl->servaddr), 1);
 403                         setenv("SERVER_ADDR", sa_straddr(&cl->servaddr), 1);
 404                         setenv("SERVER_PORT", sa_strport(&cl->servaddr), 1);
 405                         setenv("REMOTE_HOST", sa_straddr(&cl->peeraddr), 1);
 406                         setenv("REMOTE_ADDR", sa_straddr(&cl->peeraddr), 1);
 407                         setenv("REMOTE_PORT", sa_strport(&cl->peeraddr), 1);
 408
 409                         /* path information */
 410                         setenv("SCRIPT_NAME", pi->name, 1);
 411                         setenv("SCRIPT_FILENAME", pi->phys, 1);
 412                         setenv("DOCUMENT_ROOT", pi->root, 1);
 413                         setenv("QUERY_STRING", pi->query ? pi->query : "", 1);
 414
 415                         if (pi->info)
 416                                 setenv("PATH_INFO", pi->info, 1);
 417
 418                         /* REDIRECT_STATUS, php-cgi wants it */
 419                         switch (req->redirect_status)
 420                         {
 421                                 case 404:
 422                                         setenv("REDIRECT_STATUS", "404", 1);
 423                                         break;
 424
 425                                 default:
 426                                         setenv("REDIRECT_STATUS", "200", 1);
 427                                         break;
 428                         }
 429
 430                         /* http version */
 431                         if (req->version > 1.0)
 432                                 setenv("SERVER_PROTOCOL", "HTTP/1.1", 1);
 433                         else
 434                                 setenv("SERVER_PROTOCOL", "HTTP/1.0", 1);
 435
 436                         /* request method */
 437                         switch (req->method)
 438                         {
 439                                 case UH_HTTP_MSG_GET:
 440                                         setenv("REQUEST_METHOD", "GET", 1);
 441                                         break;
 442
 443                                 case UH_HTTP_MSG_HEAD:
 444                                         setenv("REQUEST_METHOD", "HEAD", 1);
 445                                         break;
 446
 447                                 case UH_HTTP_MSG_POST:
 448                                         setenv("REQUEST_METHOD", "POST", 1);
 449                                         break;
 450                         }
 451
 452                         /* request url */
 453                         setenv("REQUEST_URI", req->url, 1);
 454
 455                         /* remote user */
 456                         if (req->realm)
 457                                 setenv("REMOTE_USER", req->realm->user, 1);
 458
 459                         /* request message headers */
 460                         foreach_header(i, req->headers)
 461                         {
 462                                 if (!strcasecmp(req->headers[i], "Accept"))
 463                                         setenv("HTTP_ACCEPT", req->headers[i+1], 1);
 464
 465                                 else if (!strcasecmp(req->headers[i], "Accept-Charset"))
 466                                         setenv("HTTP_ACCEPT_CHARSET", req->headers[i+1], 1);
 467
 468                                 else if (!strcasecmp(req->headers[i], "Accept-Encoding"))
 469                                         setenv("HTTP_ACCEPT_ENCODING", req->headers[i+1], 1);
 470
 471                                 else if (!strcasecmp(req->headers[i], "Accept-Language"))
 472                                         setenv("HTTP_ACCEPT_LANGUAGE", req->headers[i+1], 1);
 473
 474                                 else if (!strcasecmp(req->headers[i], "Authorization"))
 475                                         setenv("HTTP_AUTHORIZATION", req->headers[i+1], 1);
 476
 477                                 else if (!strcasecmp(req->headers[i], "Connection"))
 478                                         setenv("HTTP_CONNECTION", req->headers[i+1], 1);
 479
 480                                 else if (!strcasecmp(req->headers[i], "Cookie"))
 481                                         setenv("HTTP_COOKIE", req->headers[i+1], 1);
 482
 483                                 else if (!strcasecmp(req->headers[i], "Host"))
 484                                         setenv("HTTP_HOST", req->headers[i+1], 1);
 485
 486                                 else if (!strcasecmp(req->headers[i], "Referer"))
 487                                         setenv("HTTP_REFERER", req->headers[i+1], 1);
 488
 489                                 else if (!strcasecmp(req->headers[i], "User-Agent"))
 490                                         setenv("HTTP_USER_AGENT", req->headers[i+1], 1);
 491
 492                                 else if (!strcasecmp(req->headers[i], "Content-Type"))
 493                                         setenv("CONTENT_TYPE", req->headers[i+1], 1);
 494
 495                                 else if (!strcasecmp(req->headers[i], "Content-Length"))
 496                                         setenv("CONTENT_LENGTH", req->headers[i+1], 1);
 497                         }
 498
 499
 500                         /* execute child code ... */
 501                         if (chdir(pi->root))
 502                                 perror("chdir()");
 503
 504                         if (ip != NULL)
 505                                 execl(ip->path, ip->path, pi->phys, NULL);
 506                         else
 507                                 execl(pi->phys, pi->phys, NULL);
 508
 509                         /* in case it fails ... */
 510                         printf("Status: 500 Internal Server Error\r\n\r\n"
 511                                    "Unable to launch the requested CGI program:\n"
 512                                    "  %s: %s\n", ip ? ip->path : pi->phys, strerror(errno));
 513                 }
 514
 515                 /* 403 */
 516                 else
 517                 {
 518                         printf("Status: 403 Forbidden\r\n\r\n"
 519                                    "Access to this resource is forbidden\n");
 520                 }
 521
 522                 close(wfd[0]);
 523                 close(rfd[1]);
 524                 exit(0);
 525
 526                 break;
 527
 528         /* parent; handle I/O relaying */
 529         default:
 530                 memset(state, 0, sizeof(*state));
 531
 532                 state->cl = cl;
 533                 state->cl->pipe.fd = rfd[0];
 534                 state->cl->proc.pid = child;
 535
 536                 /* close unneeded pipe ends */
 537                 close(rfd[1]);
 538                 close(wfd[0]);
 539
 540                 D("CGI: Child(%d) created: rfd(%d) wfd(%d)\n", child, rfd[0], wfd[1]);
 541
 542                 state->content_length = cl->httpbuf.len;
 543
 544                 /* find content length */
 545                 if (req->method == UH_HTTP_MSG_POST)
 546                 {
 547                         foreach_header(i, req->headers)
 548                         {
 549                                 if (!strcasecmp(req->headers[i], "Content-Length"))
 550                                 {
 551                                         state->content_length = atoi(req->headers[i+1]);
 552                                         break;
 553                                 }
 554                         }
 555                 }
 556
 557                 state->rfd = rfd[0];
 558                 fd_nonblock(state->rfd);
 559
 560                 state->wfd = wfd[1];
 561                 fd_nonblock(state->wfd);
 562
 563                 cl->cb = uh_cgi_socket_cb;
 564                 cl->priv = state;
 565
 566                 break;
 567         }
 568
 569         return true;
 570 }