contrib/package/uhttpd/src/uhttpd-cgi.c

   1 #include "uhttpd.h"
   2 #include "uhttpd-utils.h"
   3 #include "uhttpd-cgi.h"
   4
   5 static struct http_response * uh_cgi_header_parse(char *buf, int len, int *off)
   6 {
   7         char *bufptr = NULL;
   8         char *hdrname = NULL;
   9         int hdrcount = 0;
  10         int pos = 0;
  11
  12         static struct http_response res;
  13
  14
  15         if( ((bufptr = strfind(buf, len, "\r\n\r\n", 4)) != NULL) ||
  16             ((bufptr = strfind(buf, len, "\n\n", 2)) != NULL)
  17         ) {
  18                 *off = (int)(bufptr - buf) + ((bufptr[0] == '\r') ? 4 : 2);
  19
  20                 memset(&res, 0, sizeof(res));
  21
  22                 res.statuscode = 200;
  23                 res.statusmsg  = "OK";
  24
  25                 bufptr = &buf[0];
  26
  27                 for( pos = 0; pos < len; pos++ )
  28                 {
  29                         if( !hdrname && (buf[pos] == ':') )
  30                         {
  31                                 buf[pos++] = 0;
  32
  33                                 if( (pos < len) && (buf[pos] == ' ') )
  34                                         pos++;
  35
  36                                 if( pos < len )
  37                                 {
  38                                         hdrname = bufptr;
  39                                         bufptr = &buf[pos];
  40                                 }
  41                         }
  42
  43                         else if( (buf[pos] == '\r') || (buf[pos] == '\n') )
  44                         {
  45                                 buf[pos++] = 0;
  46
  47                                 if( ! hdrname )
  48                                         break;
  49
  50                                 if( (pos < len) && (buf[pos] == '\n') )
  51                                         pos++;
  52
  53                                 if( pos < len )
  54                                 {
  55                                         if( (hdrcount + 1) < array_size(res.headers) )
  56                                         {
  57                                                 if( ! strcasecmp(hdrname, "Status") )
  58                                                 {
  59                                                         res.statuscode = atoi(bufptr);
  60
  61                                                         if( res.statuscode < 100 )
  62                                                                 res.statuscode = 200;
  63
  64                                                         if( ((bufptr = strchr(bufptr, ' ')) != NULL) && (&bufptr[1] != 0) )
  65                                                                 res.statusmsg = &bufptr[1];
  66                                                 }
  67                                                 else
  68                                                 {
  69                                                         res.headers[hdrcount++] = hdrname;
  70                                                         res.headers[hdrcount++] = bufptr;
  71                                                 }
  72
  73                                                 bufptr = &buf[pos];
  74                                                 hdrname = NULL;
  75                                         }
  76                                         else
  77                                         {
  78                                                 return NULL;
  79                                         }
  80                                 }
  81                         }
  82                 }
  83
  84                 return &res;
  85         }
  86
  87         return NULL;
  88 }
  89
  90 static char * uh_cgi_header_lookup(struct http_response *res, const char *hdrname)
  91 {
  92         int i;
  93
  94         foreach_header(i, res->headers)
  95         {
  96                 if( ! strcasecmp(res->headers[i], hdrname) )
  97                         return res->headers[i+1];
  98         }
  99
 100         return NULL;
 101 }
 102
 103 static void uh_cgi_error_500(struct client *cl, struct http_request *req, const char *message)
 104 {
 105         uh_http_sendf(cl, NULL,
 106                 "HTTP/%.1f 500 Internal Server Error\r\n"
 107                 "Content-Type: text/plain\r\n%s\r\n",
 108                         req->version,
 109                         (req->version > 1.0)
 110                                 ? "Transfer-Encoding: chunked\r\n" : ""
 111         );
 112
 113         uh_http_send(cl, req, message, -1);
 114 }
 115
 116
 117 void uh_cgi_request(struct client *cl, struct http_request *req, struct uh_path_info *pi)
 118 {
 119         int i, hdroff, bufoff;
 120         int hdrlen = 0;
 121         int buflen = 0;
 122         int fd_max = 0;
 123         int content_length = 0;
 124         int header_sent = 0;
 125
 126         int rfd[2] = { 0, 0 };
 127         int wfd[2] = { 0, 0 };
 128
 129         char buf[UH_LIMIT_MSGHEAD];
 130         char hdr[UH_LIMIT_MSGHEAD];
 131
 132         fd_set reader;
 133         fd_set writer;
 134
 135         struct timeval timeout;
 136         struct http_response *res;
 137
 138
 139         /* spawn pipes for me->child, child->me */
 140         if( (pipe(rfd) < 0) || (pipe(wfd) < 0) )
 141         {
 142                 uh_http_sendhf(cl, 500, "Internal Server Error",
 143                         "Failed to create pipe: %s", strerror(errno));
 144
 145                 if( rfd[0] > 0 ) close(rfd[0]);
 146                 if( rfd[1] > 0 ) close(rfd[1]);
 147                 if( wfd[0] > 0 ) close(wfd[0]);
 148                 if( wfd[1] > 0 ) close(wfd[1]);
 149
 150                 return;
 151         }
 152
 153         /* fork off child process */
 154         switch( fork() )
 155         {
 156                 /* oops */
 157                 case -1:
 158                         uh_http_sendhf(cl, 500, "Internal Server Error",
 159                                 "Failed to fork child: %s", strerror(errno));
 160                         return;
 161
 162                 /* exec child */
 163                 case 0:
 164                         /* child */
 165                         close(rfd[0]);
 166                         close(wfd[1]);
 167
 168                         /* patch stdout and stdin to pipes */
 169                         dup2(rfd[1], 1);
 170                         dup2(wfd[0], 0);
 171
 172                         /* check for regular, world-executable file */
 173                         if( (pi->stat.st_mode & S_IFREG) &&
 174                             (pi->stat.st_mode & S_IXOTH)
 175                         ) {
 176                                 /* build environment */
 177                                 clearenv();
 178
 179                                 /* common information */
 180                                 setenv("GATEWAY_INTERFACE", "CGI/1.1", 1);
 181                                 setenv("SERVER_SOFTWARE", "uHTTPd", 1);
 182                                 setenv("PATH", "/sbin:/usr/sbin:/bin:/usr/bin", 1);
 183
 184 #ifdef HAVE_TLS
 185                                 /* https? */
 186                                 if( cl->tls )
 187                                         setenv("HTTPS", "on", 1);
 188 #endif
 189
 190                                 /* addresses */
 191                                 setenv("SERVER_NAME", sa_straddr(&cl->servaddr), 1);
 192                                 setenv("SERVER_ADDR", sa_straddr(&cl->servaddr), 1);
 193                                 setenv("SERVER_PORT", sa_strport(&cl->servaddr), 1);
 194                                 setenv("REMOTE_HOST", sa_straddr(&cl->peeraddr), 1);
 195                                 setenv("REMOTE_ADDR", sa_straddr(&cl->peeraddr), 1);
 196                                 setenv("REMOTE_PORT", sa_strport(&cl->peeraddr), 1);
 197
 198                                 /* path information */
 199                                 setenv("SCRIPT_NAME", pi->name, 1);
 200                                 setenv("SCRIPT_FILENAME", pi->phys, 1);
 201                                 setenv("DOCUMENT_ROOT", pi->root, 1);
 202                                 setenv("QUERY_STRING", pi->query ? pi->query : "", 1);
 203
 204                                 if( pi->info )
 205                                         setenv("PATH_INFO", pi->info, 1);
 206
 207
 208                                 /* http version */
 209                                 if( req->version > 1.0 )
 210                                         setenv("SERVER_PROTOCOL", "HTTP/1.1", 1);
 211                                 else
 212                                         setenv("SERVER_PROTOCOL", "HTTP/1.0", 1);
 213
 214                                 /* request method */
 215                                 switch( req->method )
 216                                 {
 217                                         case UH_HTTP_MSG_GET:
 218                                                 setenv("REQUEST_METHOD", "GET", 1);
 219                                                 break;
 220
 221                                         case UH_HTTP_MSG_HEAD:
 222                                                 setenv("REQUEST_METHOD", "HEAD", 1);
 223                                                 break;
 224
 225                                         case UH_HTTP_MSG_POST:
 226                                                 setenv("REQUEST_METHOD", "POST", 1);
 227                                                 break;
 228                                 }
 229
 230                                 /* request url */
 231                                 setenv("REQUEST_URI", req->url, 1);
 232
 233                                 /* request message headers */
 234                                 foreach_header(i, req->headers)
 235                                 {
 236                                         if( ! strcasecmp(req->headers[i], "Accept") )
 237                                                 setenv("HTTP_ACCEPT", req->headers[i+1], 1);
 238
 239                                         else if( ! strcasecmp(req->headers[i], "Accept-Charset") )
 240                                                 setenv("HTTP_ACCEPT_CHARSET", req->headers[i+1], 1);
 241
 242                                         else if( ! strcasecmp(req->headers[i], "Accept-Encoding") )
 243                                                 setenv("HTTP_ACCEPT_ENCODING", req->headers[i+1], 1);
 244
 245                                         else if( ! strcasecmp(req->headers[i], "Accept-Language") )
 246                                                 setenv("HTTP_ACCEPT_LANGUAGE", req->headers[i+1], 1);
 247
 248                                         else if( ! strcasecmp(req->headers[i], "Authorization") )
 249                                                 setenv("HTTP_AUTHORIZATION", req->headers[i+1], 1);
 250
 251                                         else if( ! strcasecmp(req->headers[i], "Connection") )
 252                                                 setenv("HTTP_CONNECTION", req->headers[i+1], 1);
 253
 254                                         else if( ! strcasecmp(req->headers[i], "Cookie") )
 255                                                 setenv("HTTP_COOKIE", req->headers[i+1], 1);
 256
 257                                         else if( ! strcasecmp(req->headers[i], "Host") )
 258                                                 setenv("HTTP_HOST", req->headers[i+1], 1);
 259
 260                                         else if( ! strcasecmp(req->headers[i], "Referer") )
 261                                                 setenv("HTTP_REFERER", req->headers[i+1], 1);
 262
 263                                         else if( ! strcasecmp(req->headers[i], "User-Agent") )
 264                                                 setenv("HTTP_USER_AGENT", req->headers[i+1], 1);
 265
 266                                         else if( ! strcasecmp(req->headers[i], "Content-Type") )
 267                                                 setenv("CONTENT_TYPE", req->headers[i+1], 1);
 268
 269                                         else if( ! strcasecmp(req->headers[i], "Content-Length") )
 270                                                 setenv("CONTENT_LENGTH", req->headers[i+1], 1);
 271                                 }
 272
 273
 274                                 /* execute child code ... */
 275                                 if( chdir(pi->root) )
 276                                         perror("chdir()");
 277
 278                                 execl(pi->phys, pi->phys, NULL);
 279
 280                                 /* in case it fails ... */
 281                                 printf(
 282                                         "Status: 500 Internal Server Error\r\n\r\n"
 283                                         "Unable to launch the requested CGI program:\n"
 284                                         "  %s: %s\n",
 285                                                 pi->phys, strerror(errno)
 286                                 );
 287                         }
 288
 289                         /* 403 */
 290                         else
 291                         {
 292                                 printf(
 293                                         "Status: 403 Forbidden\r\n\r\n"
 294                                         "Access to this resource is forbidden\n"
 295                                 );
 296                         }
 297
 298                         close(wfd[0]);
 299                         close(rfd[1]);
 300                         exit(0);
 301
 302                         break;
 303
 304                 /* parent; handle I/O relaying */
 305                 default:
 306                         /* close unneeded pipe ends */
 307                         close(rfd[1]);
 308                         close(wfd[0]);
 309
 310                         /* max watch fd */
 311                         fd_max = max(rfd[0], wfd[1]) + 1;
 312
 313                         /* find content length */
 314                         if( req->method == UH_HTTP_MSG_POST )
 315                         {
 316                                 foreach_header(i, req->headers)
 317                                 {
 318                                         if( ! strcasecmp(req->headers[i], "Content-Length") )
 319                                         {
 320                                                 content_length = atoi(req->headers[i+1]);
 321                                                 break;
 322                                         }
 323                                 }
 324                         }
 325
 326
 327                         memset(hdr, 0, sizeof(hdr));
 328
 329                         /* I/O loop, watch our pipe ends and dispatch child reads/writes from/to socket */
 330                         while( 1 )
 331                         {
 332                                 FD_ZERO(&reader);
 333                                 FD_ZERO(&writer);
 334
 335                                 FD_SET(rfd[0], &reader);
 336                                 FD_SET(wfd[1], &writer);
 337
 338                                 timeout.tv_sec = 3;
 339                                 timeout.tv_usec = 0;
 340
 341                                 /* wait until we can read or write or both */
 342                                 if( select(fd_max, &reader, (content_length > -1) ? &writer : NULL, NULL, &timeout) > 0 )
 343                                 {
 344                                         /* ready to write to cgi program */
 345                                         if( FD_ISSET(wfd[1], &writer) )
 346                                         {
 347                                                 /* there is unread post data waiting */
 348                                                 if( content_length > 0 )
 349                                                 {
 350                                                         /* read it from socket ... */
 351                                                         if( (buflen = uh_tcp_recv(cl, buf, min(content_length, sizeof(buf)))) > 0 )
 352                                                         {
 353                                                                 /* ... and write it to child's stdin */
 354                                                                 if( write(wfd[1], buf, buflen) < 0 )
 355                                                                         perror("write()");
 356
 357                                                                 content_length -= buflen;
 358                                                         }
 359
 360                                                         /* unexpected eof! */
 361                                                         else
 362                                                         {
 363                                                                 if( write(wfd[1], "", 0) < 0 )
 364                                                                         perror("write()");
 365
 366                                                                 content_length = 0;
 367                                                         }
 368                                                 }
 369
 370                                                 /* there is no more post data, close pipe to child's stdin */
 371                                                 else
 372                                                 {
 373                                                         close(wfd[1]);
 374                                                         content_length = -1;
 375                                                 }
 376                                         }
 377
 378                                         /* ready to read from cgi program */
 379                                         if( FD_ISSET(rfd[0], &reader) )
 380                                         {
 381                                                 /* read data from child ... */
 382                                                 if( (buflen = read(rfd[0], buf, sizeof(buf))) > 0 )
 383                                                 {
 384                                                         /* we have not pushed out headers yet, parse input */
 385                                                         if( ! header_sent )
 386                                                         {
 387                                                                 /* head buffer not full and no end yet */
 388                                                                 if( hdrlen < sizeof(hdr) )
 389                                                                 {
 390                                                                         bufoff = min(buflen, sizeof(hdr) - hdrlen);
 391                                                                         memcpy(&hdr[hdrlen], buf, bufoff);
 392                                                                         hdrlen += bufoff;
 393                                                                 }
 394                                                                 else
 395                                                                 {
 396                                                                         bufoff = 0;
 397                                                                 }
 398
 399
 400                                                                 /* try to parse header ... */
 401                                                                 if( (res = uh_cgi_header_parse(hdr, hdrlen, &hdroff)) != NULL )
 402                                                                 {
 403                                                                         /* write status */
 404                                                                         uh_http_sendf(cl, NULL, "HTTP/%.1f %03d %s\r\n",
 405                                                                                 req->version, res->statuscode, res->statusmsg);
 406
 407                                                                         /* add Content-Type if no Location or Content-Type */
 408                                                                         if( !uh_cgi_header_lookup(res, "Location") &&
 409                                                                             !uh_cgi_header_lookup(res, "Content-Type")
 410                                                                         ) {
 411                                                                                 uh_http_send(cl, NULL,
 412                                                                                         "Content-Type: text/plain\r\n", -1);
 413                                                                         }
 414
 415                                                                         /* if request was HTTP 1.1 we'll respond chunked */
 416                                                                         if( (req->version > 1.0) &&
 417                                                                             !uh_cgi_header_lookup(res, "Transfer-Encoding")
 418                                                                         ) {
 419                                                                                 uh_http_send(cl, NULL,
 420                                                                                         "Transfer-Encoding: chunked\r\n", -1);
 421                                                                         }
 422
 423                                                                         /* write headers from CGI program */
 424                                                                         foreach_header(i, res->headers)
 425                                                                         {
 426                                                                                 uh_http_sendf(cl, NULL, "%s: %s\r\n",
 427                                                                                         res->headers[i], res->headers[i+1]);
 428                                                                         }
 429
 430                                                                         /* terminate header */
 431                                                                         uh_http_send(cl, NULL, "\r\n", -1);
 432
 433                                                                         /* push out remaining head buffer */
 434                                                                         if( hdroff < hdrlen )
 435                                                                                 uh_http_send(cl, req, &hdr[hdroff], hdrlen - hdroff);
 436                                                                 }
 437
 438                                                                 /* ... failed and head buffer exceeded */
 439                                                                 else if( hdrlen >= sizeof(hdr) )
 440                                                                 {
 441                                                                         uh_cgi_error_500(cl, req,
 442                                                                                 "The CGI program generated an invalid response:\n\n");
 443
 444                                                                         uh_http_send(cl, req, hdr, hdrlen);
 445                                                                 }
 446
 447                                                                 /* ... failed but free buffer space, try again */
 448                                                                 else
 449                                                                 {
 450                                                                         continue;
 451                                                                 }
 452
 453                                                                 /* push out remaining read buffer */
 454                                                                 if( bufoff < buflen )
 455                                                                         uh_http_send(cl, req, &buf[bufoff], buflen - bufoff);
 456
 457                                                                 header_sent = 1;
 458                                                                 continue;
 459                                                         }
 460
 461
 462                                                         /* headers complete, pass through buffer to socket */
 463                                                         uh_http_send(cl, req, buf, buflen);
 464                                                 }
 465
 466                                                 /* looks like eof from child */
 467                                                 else
 468                                                 {
 469                                                         /* cgi script did not output useful stuff at all */
 470                                                         if( ! header_sent )
 471                                                         {
 472                                                                 /* I would do this ...
 473                                                                  *
 474                                                                  *    uh_cgi_error_500(cl, req,
 475                                                                  *        "The CGI program generated an "
 476                                                                  *        "invalid response:\n\n");
 477                                                                  *
 478                                                                  * ... but in order to stay as compatible as possible,
 479                                                                  * treat whatever we got as text/plain response and
 480                                                                  * build the required headers here.
 481                                                                  */
 482
 483                                                                 uh_http_sendf(cl, NULL,
 484                                                                         "HTTP/%.1f 200 OK\r\n"
 485                                                                         "Content-Type: text/plain\r\n"
 486                                                                         "%s\r\n",
 487                                                                                 req->version, (req->version > 1.0)
 488                                                                                         ? "Transfer-Encoding: chunked\r\n" : ""
 489                                                                 );
 490
 491                                                                 uh_http_send(cl, req, hdr, hdrlen);
 492                                                         }
 493
 494                                                         /* send final chunk if we're in chunked transfer mode */
 495                                                         uh_http_send(cl, req, "", 0);
 496                                                         break;
 497                                                 }
 498                                         }
 499                                 }
 500
 501                                 /* no activity for 3 seconds... looks dead */
 502                                 else
 503                                 {
 504                                         uh_http_sendhf(cl, 504, "Gateway Timeout",
 505                                                 "The CGI script took too long to produce a response");
 506
 507                                         break;
 508                                 }
 509                         }
 510
 511                         close(rfd[0]);
 512                         close(wfd[1]);
 513
 514                         break;
 515         }
 516 }
 517