| 1 | /* |
| 2 | * uhttpd - Tiny single-threaded httpd - CGI handler |
| 3 | * |
| 4 | * Copyright (C) 2010 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 | static struct http_response * uh_cgi_header_parse(char *buf, int len, int *off) |
| 24 | { |
| 25 | char *bufptr = NULL; |
| 26 | char *hdrname = NULL; |
| 27 | int hdrcount = 0; |
| 28 | int pos = 0; |
| 29 | |
| 30 | static struct http_response res; |
| 31 | |
| 32 | |
| 33 | if( ((bufptr = strfind(buf, len, "\r\n\r\n", 4)) != NULL) || |
| 34 | ((bufptr = strfind(buf, len, "\n\n", 2)) != NULL) |
| 35 | ) { |
| 36 | *off = (int)(bufptr - buf) + ((bufptr[0] == '\r') ? 4 : 2); |
| 37 | |
| 38 | memset(&res, 0, sizeof(res)); |
| 39 | |
| 40 | res.statuscode = 200; |
| 41 | res.statusmsg = "OK"; |
| 42 | |
| 43 | bufptr = &buf[0]; |
| 44 | |
| 45 | for( pos = 0; pos < len; pos++ ) |
| 46 | { |
| 47 | if( !hdrname && (buf[pos] == ':') ) |
| 48 | { |
| 49 | buf[pos++] = 0; |
| 50 | |
| 51 | if( (pos < len) && (buf[pos] == ' ') ) |
| 52 | pos++; |
| 53 | |
| 54 | if( pos < len ) |
| 55 | { |
| 56 | hdrname = bufptr; |
| 57 | bufptr = &buf[pos]; |
| 58 | } |
| 59 | } |
| 60 | |
| 61 | else if( (buf[pos] == '\r') || (buf[pos] == '\n') ) |
| 62 | { |
| 63 | buf[pos++] = 0; |
| 64 | |
| 65 | if( ! hdrname ) |
| 66 | break; |
| 67 | |
| 68 | if( (pos < len) && (buf[pos] == '\n') ) |
| 69 | pos++; |
| 70 | |
| 71 | if( pos <= len ) |
| 72 | { |
| 73 | if( (hdrcount + 1) < array_size(res.headers) ) |
| 74 | { |
| 75 | if( ! strcasecmp(hdrname, "Status") ) |
| 76 | { |
| 77 | res.statuscode = atoi(bufptr); |
| 78 | |
| 79 | if( res.statuscode < 100 ) |
| 80 | res.statuscode = 200; |
| 81 | |
| 82 | if( ((bufptr = strchr(bufptr, ' ')) != NULL) && (&bufptr[1] != 0) ) |
| 83 | res.statusmsg = &bufptr[1]; |
| 84 | } |
| 85 | else |
| 86 | { |
| 87 | res.headers[hdrcount++] = hdrname; |
| 88 | res.headers[hdrcount++] = bufptr; |
| 89 | } |
| 90 | |
| 91 | bufptr = &buf[pos]; |
| 92 | hdrname = NULL; |
| 93 | } |
| 94 | else |
| 95 | { |
| 96 | return NULL; |
| 97 | } |
| 98 | } |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | return &res; |
| 103 | } |
| 104 | |
| 105 | return NULL; |
| 106 | } |
| 107 | |
| 108 | static char * uh_cgi_header_lookup(struct http_response *res, const char *hdrname) |
| 109 | { |
| 110 | int i; |
| 111 | |
| 112 | foreach_header(i, res->headers) |
| 113 | { |
| 114 | if( ! strcasecmp(res->headers[i], hdrname) ) |
| 115 | return res->headers[i+1]; |
| 116 | } |
| 117 | |
| 118 | return NULL; |
| 119 | } |
| 120 | |
| 121 | static int uh_cgi_error_500(struct client *cl, struct http_request *req, const char *message) |
| 122 | { |
| 123 | if( uh_http_sendf(cl, NULL, |
| 124 | "HTTP/%.1f 500 Internal Server Error\r\n" |
| 125 | "Content-Type: text/plain\r\n%s\r\n", |
| 126 | req->version, |
| 127 | (req->version > 1.0) |
| 128 | ? "Transfer-Encoding: chunked\r\n" : "" |
| 129 | ) >= 0 |
| 130 | ) { |
| 131 | return uh_http_send(cl, req, message, -1); |
| 132 | } |
| 133 | |
| 134 | return -1; |
| 135 | } |
| 136 | |
| 137 | |
| 138 | void uh_cgi_request(struct client *cl, struct http_request *req, struct path_info *pi) |
| 139 | { |
| 140 | int i, hdroff, bufoff; |
| 141 | int hdrlen = 0; |
| 142 | int buflen = 0; |
| 143 | int fd_max = 0; |
| 144 | int content_length = 0; |
| 145 | int header_sent = 0; |
| 146 | |
| 147 | int rfd[2] = { 0, 0 }; |
| 148 | int wfd[2] = { 0, 0 }; |
| 149 | |
| 150 | char buf[UH_LIMIT_MSGHEAD]; |
| 151 | char hdr[UH_LIMIT_MSGHEAD]; |
| 152 | |
| 153 | pid_t child; |
| 154 | |
| 155 | fd_set reader; |
| 156 | fd_set writer; |
| 157 | |
| 158 | struct sigaction sa; |
| 159 | struct timeval timeout; |
| 160 | struct http_response *res; |
| 161 | |
| 162 | |
| 163 | /* spawn pipes for me->child, child->me */ |
| 164 | if( (pipe(rfd) < 0) || (pipe(wfd) < 0) ) |
| 165 | { |
| 166 | uh_http_sendhf(cl, 500, "Internal Server Error", |
| 167 | "Failed to create pipe: %s", strerror(errno)); |
| 168 | |
| 169 | if( rfd[0] > 0 ) close(rfd[0]); |
| 170 | if( rfd[1] > 0 ) close(rfd[1]); |
| 171 | if( wfd[0] > 0 ) close(wfd[0]); |
| 172 | if( wfd[1] > 0 ) close(wfd[1]); |
| 173 | |
| 174 | return; |
| 175 | } |
| 176 | |
| 177 | /* fork off child process */ |
| 178 | switch( (child = fork()) ) |
| 179 | { |
| 180 | /* oops */ |
| 181 | case -1: |
| 182 | uh_http_sendhf(cl, 500, "Internal Server Error", |
| 183 | "Failed to fork child: %s", strerror(errno)); |
| 184 | return; |
| 185 | |
| 186 | /* exec child */ |
| 187 | case 0: |
| 188 | /* restore SIGTERM */ |
| 189 | sa.sa_flags = 0; |
| 190 | sa.sa_handler = SIG_DFL; |
| 191 | sigemptyset(&sa.sa_mask); |
| 192 | sigaction(SIGTERM, &sa, NULL); |
| 193 | |
| 194 | /* close loose pipe ends */ |
| 195 | close(rfd[0]); |
| 196 | close(wfd[1]); |
| 197 | |
| 198 | /* patch stdout and stdin to pipes */ |
| 199 | dup2(rfd[1], 1); |
| 200 | dup2(wfd[0], 0); |
| 201 | |
| 202 | /* check for regular, world-executable file */ |
| 203 | if( (pi->stat.st_mode & S_IFREG) && |
| 204 | (pi->stat.st_mode & S_IXOTH) |
| 205 | ) { |
| 206 | /* build environment */ |
| 207 | clearenv(); |
| 208 | |
| 209 | /* common information */ |
| 210 | setenv("GATEWAY_INTERFACE", "CGI/1.1", 1); |
| 211 | setenv("SERVER_SOFTWARE", "uHTTPd", 1); |
| 212 | setenv("PATH", "/sbin:/usr/sbin:/bin:/usr/bin", 1); |
| 213 | |
| 214 | #ifdef HAVE_TLS |
| 215 | /* https? */ |
| 216 | if( cl->tls ) |
| 217 | setenv("HTTPS", "on", 1); |
| 218 | #endif |
| 219 | |
| 220 | /* addresses */ |
| 221 | setenv("SERVER_NAME", sa_straddr(&cl->servaddr), 1); |
| 222 | setenv("SERVER_ADDR", sa_straddr(&cl->servaddr), 1); |
| 223 | setenv("SERVER_PORT", sa_strport(&cl->servaddr), 1); |
| 224 | setenv("REMOTE_HOST", sa_straddr(&cl->peeraddr), 1); |
| 225 | setenv("REMOTE_ADDR", sa_straddr(&cl->peeraddr), 1); |
| 226 | setenv("REMOTE_PORT", sa_strport(&cl->peeraddr), 1); |
| 227 | |
| 228 | /* path information */ |
| 229 | setenv("SCRIPT_NAME", pi->name, 1); |
| 230 | setenv("SCRIPT_FILENAME", pi->phys, 1); |
| 231 | setenv("DOCUMENT_ROOT", pi->root, 1); |
| 232 | setenv("QUERY_STRING", pi->query ? pi->query : "", 1); |
| 233 | |
| 234 | if( pi->info ) |
| 235 | setenv("PATH_INFO", pi->info, 1); |
| 236 | |
| 237 | /* REDIRECT_STATUS, php-cgi wants it */ |
| 238 | switch( req->redirect_status ) |
| 239 | { |
| 240 | case 404: |
| 241 | setenv("REDIRECT_STATUS", "404", 1); |
| 242 | break; |
| 243 | |
| 244 | default: |
| 245 | setenv("REDIRECT_STATUS", "200", 1); |
| 246 | break; |
| 247 | } |
| 248 | |
| 249 | /* http version */ |
| 250 | if( req->version > 1.0 ) |
| 251 | setenv("SERVER_PROTOCOL", "HTTP/1.1", 1); |
| 252 | else |
| 253 | setenv("SERVER_PROTOCOL", "HTTP/1.0", 1); |
| 254 | |
| 255 | /* request method */ |
| 256 | switch( req->method ) |
| 257 | { |
| 258 | case UH_HTTP_MSG_GET: |
| 259 | setenv("REQUEST_METHOD", "GET", 1); |
| 260 | break; |
| 261 | |
| 262 | case UH_HTTP_MSG_HEAD: |
| 263 | setenv("REQUEST_METHOD", "HEAD", 1); |
| 264 | break; |
| 265 | |
| 266 | case UH_HTTP_MSG_POST: |
| 267 | setenv("REQUEST_METHOD", "POST", 1); |
| 268 | break; |
| 269 | } |
| 270 | |
| 271 | /* request url */ |
| 272 | setenv("REQUEST_URI", req->url, 1); |
| 273 | |
| 274 | /* remote user */ |
| 275 | if( req->realm ) |
| 276 | setenv("REMOTE_USER", req->realm->user, 1); |
| 277 | |
| 278 | /* request message headers */ |
| 279 | foreach_header(i, req->headers) |
| 280 | { |
| 281 | if( ! strcasecmp(req->headers[i], "Accept") ) |
| 282 | setenv("HTTP_ACCEPT", req->headers[i+1], 1); |
| 283 | |
| 284 | else if( ! strcasecmp(req->headers[i], "Accept-Charset") ) |
| 285 | setenv("HTTP_ACCEPT_CHARSET", req->headers[i+1], 1); |
| 286 | |
| 287 | else if( ! strcasecmp(req->headers[i], "Accept-Encoding") ) |
| 288 | setenv("HTTP_ACCEPT_ENCODING", req->headers[i+1], 1); |
| 289 | |
| 290 | else if( ! strcasecmp(req->headers[i], "Accept-Language") ) |
| 291 | setenv("HTTP_ACCEPT_LANGUAGE", req->headers[i+1], 1); |
| 292 | |
| 293 | else if( ! strcasecmp(req->headers[i], "Authorization") ) |
| 294 | setenv("HTTP_AUTHORIZATION", req->headers[i+1], 1); |
| 295 | |
| 296 | else if( ! strcasecmp(req->headers[i], "Connection") ) |
| 297 | setenv("HTTP_CONNECTION", req->headers[i+1], 1); |
| 298 | |
| 299 | else if( ! strcasecmp(req->headers[i], "Cookie") ) |
| 300 | setenv("HTTP_COOKIE", req->headers[i+1], 1); |
| 301 | |
| 302 | else if( ! strcasecmp(req->headers[i], "Host") ) |
| 303 | setenv("HTTP_HOST", req->headers[i+1], 1); |
| 304 | |
| 305 | else if( ! strcasecmp(req->headers[i], "Referer") ) |
| 306 | setenv("HTTP_REFERER", req->headers[i+1], 1); |
| 307 | |
| 308 | else if( ! strcasecmp(req->headers[i], "User-Agent") ) |
| 309 | setenv("HTTP_USER_AGENT", req->headers[i+1], 1); |
| 310 | |
| 311 | else if( ! strcasecmp(req->headers[i], "Content-Type") ) |
| 312 | setenv("CONTENT_TYPE", req->headers[i+1], 1); |
| 313 | |
| 314 | else if( ! strcasecmp(req->headers[i], "Content-Length") ) |
| 315 | setenv("CONTENT_LENGTH", req->headers[i+1], 1); |
| 316 | } |
| 317 | |
| 318 | |
| 319 | /* execute child code ... */ |
| 320 | if( chdir(pi->root) ) |
| 321 | perror("chdir()"); |
| 322 | |
| 323 | execl(pi->phys, pi->phys, NULL); |
| 324 | |
| 325 | /* in case it fails ... */ |
| 326 | printf( |
| 327 | "Status: 500 Internal Server Error\r\n\r\n" |
| 328 | "Unable to launch the requested CGI program:\n" |
| 329 | " %s: %s\n", |
| 330 | pi->phys, strerror(errno) |
| 331 | ); |
| 332 | } |
| 333 | |
| 334 | /* 403 */ |
| 335 | else |
| 336 | { |
| 337 | printf( |
| 338 | "Status: 403 Forbidden\r\n\r\n" |
| 339 | "Access to this resource is forbidden\n" |
| 340 | ); |
| 341 | } |
| 342 | |
| 343 | close(wfd[0]); |
| 344 | close(rfd[1]); |
| 345 | exit(0); |
| 346 | |
| 347 | break; |
| 348 | |
| 349 | /* parent; handle I/O relaying */ |
| 350 | default: |
| 351 | /* close unneeded pipe ends */ |
| 352 | close(rfd[1]); |
| 353 | close(wfd[0]); |
| 354 | |
| 355 | /* max watch fd */ |
| 356 | fd_max = max(rfd[0], wfd[1]) + 1; |
| 357 | |
| 358 | /* find content length */ |
| 359 | if( req->method == UH_HTTP_MSG_POST ) |
| 360 | { |
| 361 | foreach_header(i, req->headers) |
| 362 | { |
| 363 | if( ! strcasecmp(req->headers[i], "Content-Length") ) |
| 364 | { |
| 365 | content_length = atoi(req->headers[i+1]); |
| 366 | break; |
| 367 | } |
| 368 | } |
| 369 | } |
| 370 | |
| 371 | |
| 372 | memset(hdr, 0, sizeof(hdr)); |
| 373 | |
| 374 | timeout.tv_sec = cl->server->conf->script_timeout; |
| 375 | timeout.tv_usec = 0; |
| 376 | |
| 377 | #define ensure(x) \ |
| 378 | do { if( x < 0 ) goto out; } while(0) |
| 379 | |
| 380 | /* I/O loop, watch our pipe ends and dispatch child reads/writes from/to socket */ |
| 381 | while( 1 ) |
| 382 | { |
| 383 | FD_ZERO(&reader); |
| 384 | FD_ZERO(&writer); |
| 385 | |
| 386 | FD_SET(rfd[0], &reader); |
| 387 | FD_SET(wfd[1], &writer); |
| 388 | |
| 389 | /* wait until we can read or write or both */ |
| 390 | if( select_intr(fd_max, &reader, |
| 391 | (content_length > -1) ? &writer : NULL, NULL, |
| 392 | (header_sent < 1) ? &timeout : NULL) > 0 |
| 393 | ) { |
| 394 | /* ready to write to cgi program */ |
| 395 | if( FD_ISSET(wfd[1], &writer) ) |
| 396 | { |
| 397 | /* there is unread post data waiting */ |
| 398 | if( content_length > 0 ) |
| 399 | { |
| 400 | /* read it from socket ... */ |
| 401 | if( (buflen = uh_tcp_recv(cl, buf, min(content_length, sizeof(buf)))) > 0 ) |
| 402 | { |
| 403 | /* ... and write it to child's stdin */ |
| 404 | if( write(wfd[1], buf, buflen) < 0 ) |
| 405 | perror("write()"); |
| 406 | |
| 407 | content_length -= buflen; |
| 408 | } |
| 409 | |
| 410 | /* unexpected eof! */ |
| 411 | else |
| 412 | { |
| 413 | if( write(wfd[1], "", 0) < 0 ) |
| 414 | perror("write()"); |
| 415 | |
| 416 | content_length = 0; |
| 417 | } |
| 418 | } |
| 419 | |
| 420 | /* there is no more post data, close pipe to child's stdin */ |
| 421 | else if( content_length > -1 ) |
| 422 | { |
| 423 | close(wfd[1]); |
| 424 | content_length = -1; |
| 425 | } |
| 426 | } |
| 427 | |
| 428 | /* ready to read from cgi program */ |
| 429 | if( FD_ISSET(rfd[0], &reader) ) |
| 430 | { |
| 431 | /* read data from child ... */ |
| 432 | if( (buflen = read(rfd[0], buf, sizeof(buf))) > 0 ) |
| 433 | { |
| 434 | /* we have not pushed out headers yet, parse input */ |
| 435 | if( ! header_sent ) |
| 436 | { |
| 437 | /* head buffer not full and no end yet */ |
| 438 | if( hdrlen < sizeof(hdr) ) |
| 439 | { |
| 440 | bufoff = min(buflen, sizeof(hdr) - hdrlen); |
| 441 | memcpy(&hdr[hdrlen], buf, bufoff); |
| 442 | hdrlen += bufoff; |
| 443 | } |
| 444 | else |
| 445 | { |
| 446 | bufoff = 0; |
| 447 | } |
| 448 | |
| 449 | |
| 450 | /* try to parse header ... */ |
| 451 | if( (res = uh_cgi_header_parse(hdr, hdrlen, &hdroff)) != NULL ) |
| 452 | { |
| 453 | /* write status */ |
| 454 | ensure(uh_http_sendf(cl, NULL, |
| 455 | "HTTP/%.1f %03d %s\r\n" |
| 456 | "Connection: close\r\n", |
| 457 | req->version, res->statuscode, |
| 458 | res->statusmsg)); |
| 459 | |
| 460 | /* add Content-Type if no Location or Content-Type */ |
| 461 | if( !uh_cgi_header_lookup(res, "Location") && |
| 462 | !uh_cgi_header_lookup(res, "Content-Type") |
| 463 | ) { |
| 464 | ensure(uh_http_send(cl, NULL, |
| 465 | "Content-Type: text/plain\r\n", -1)); |
| 466 | } |
| 467 | |
| 468 | /* if request was HTTP 1.1 we'll respond chunked */ |
| 469 | if( (req->version > 1.0) && |
| 470 | !uh_cgi_header_lookup(res, "Transfer-Encoding") |
| 471 | ) { |
| 472 | ensure(uh_http_send(cl, NULL, |
| 473 | "Transfer-Encoding: chunked\r\n", -1)); |
| 474 | } |
| 475 | |
| 476 | /* write headers from CGI program */ |
| 477 | foreach_header(i, res->headers) |
| 478 | { |
| 479 | ensure(uh_http_sendf(cl, NULL, "%s: %s\r\n", |
| 480 | res->headers[i], res->headers[i+1])); |
| 481 | } |
| 482 | |
| 483 | /* terminate header */ |
| 484 | ensure(uh_http_send(cl, NULL, "\r\n", -1)); |
| 485 | |
| 486 | /* push out remaining head buffer */ |
| 487 | if( hdroff < hdrlen ) |
| 488 | ensure(uh_http_send(cl, req, &hdr[hdroff], hdrlen - hdroff)); |
| 489 | } |
| 490 | |
| 491 | /* ... failed and head buffer exceeded */ |
| 492 | else if( hdrlen >= sizeof(hdr) ) |
| 493 | { |
| 494 | ensure(uh_cgi_error_500(cl, req, |
| 495 | "The CGI program generated an invalid response:\n\n")); |
| 496 | |
| 497 | ensure(uh_http_send(cl, req, hdr, hdrlen)); |
| 498 | } |
| 499 | |
| 500 | /* ... failed but free buffer space, try again */ |
| 501 | else |
| 502 | { |
| 503 | continue; |
| 504 | } |
| 505 | |
| 506 | /* push out remaining read buffer */ |
| 507 | if( bufoff < buflen ) |
| 508 | ensure(uh_http_send(cl, req, &buf[bufoff], buflen - bufoff)); |
| 509 | |
| 510 | header_sent = 1; |
| 511 | continue; |
| 512 | } |
| 513 | |
| 514 | |
| 515 | /* headers complete, pass through buffer to socket */ |
| 516 | ensure(uh_http_send(cl, req, buf, buflen)); |
| 517 | } |
| 518 | |
| 519 | /* looks like eof from child */ |
| 520 | else |
| 521 | { |
| 522 | /* cgi script did not output useful stuff at all */ |
| 523 | if( ! header_sent ) |
| 524 | { |
| 525 | /* I would do this ... |
| 526 | * |
| 527 | * uh_cgi_error_500(cl, req, |
| 528 | * "The CGI program generated an " |
| 529 | * "invalid response:\n\n"); |
| 530 | * |
| 531 | * ... but in order to stay as compatible as possible, |
| 532 | * treat whatever we got as text/plain response and |
| 533 | * build the required headers here. |
| 534 | */ |
| 535 | |
| 536 | ensure(uh_http_sendf(cl, NULL, |
| 537 | "HTTP/%.1f 200 OK\r\n" |
| 538 | "Content-Type: text/plain\r\n" |
| 539 | "%s\r\n", |
| 540 | req->version, (req->version > 1.0) |
| 541 | ? "Transfer-Encoding: chunked\r\n" : "" |
| 542 | )); |
| 543 | |
| 544 | ensure(uh_http_send(cl, req, hdr, hdrlen)); |
| 545 | } |
| 546 | |
| 547 | /* send final chunk if we're in chunked transfer mode */ |
| 548 | ensure(uh_http_send(cl, req, "", 0)); |
| 549 | break; |
| 550 | } |
| 551 | } |
| 552 | } |
| 553 | |
| 554 | /* timeout exceeded or interrupted by SIGCHLD */ |
| 555 | else |
| 556 | { |
| 557 | if( (errno != EINTR) && ! header_sent ) |
| 558 | { |
| 559 | ensure(uh_http_sendhf(cl, 504, "Gateway Timeout", |
| 560 | "The CGI script took too long to produce " |
| 561 | "a response")); |
| 562 | } |
| 563 | |
| 564 | /* send final chunk if we're in chunked transfer mode */ |
| 565 | ensure(uh_http_send(cl, req, "", 0)); |
| 566 | |
| 567 | break; |
| 568 | } |
| 569 | } |
| 570 | |
| 571 | out: |
| 572 | close(rfd[0]); |
| 573 | close(wfd[1]); |
| 574 | |
| 575 | if( !kill(child, 0) ) |
| 576 | { |
| 577 | kill(child, SIGTERM); |
| 578 | waitpid(child, NULL, 0); |
| 579 | } |
| 580 | |
| 581 | break; |
| 582 | } |
| 583 | } |
| 584 | |
| 585 | |
