package/network/services/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         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 }