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[openwrt.git] / package / uhttpd / src / uhttpd-cgi.c
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
238 /* http version */
239 if( req->version > 1.0 )
240 setenv("SERVER_PROTOCOL", "HTTP/1.1", 1);
241 else
242 setenv("SERVER_PROTOCOL", "HTTP/1.0", 1);
243
244 /* request method */
245 switch( req->method )
246 {
247 case UH_HTTP_MSG_GET:
248 setenv("REQUEST_METHOD", "GET", 1);
249 break;
250
251 case UH_HTTP_MSG_HEAD:
252 setenv("REQUEST_METHOD", "HEAD", 1);
253 break;
254
255 case UH_HTTP_MSG_POST:
256 setenv("REQUEST_METHOD", "POST", 1);
257 break;
258 }
259
260 /* request url */
261 setenv("REQUEST_URI", req->url, 1);
262
263 /* remote user */
264 if( req->realm )
265 setenv("REMOTE_USER", req->realm->user, 1);
266
267 /* request message headers */
268 foreach_header(i, req->headers)
269 {
270 if( ! strcasecmp(req->headers[i], "Accept") )
271 setenv("HTTP_ACCEPT", req->headers[i+1], 1);
272
273 else if( ! strcasecmp(req->headers[i], "Accept-Charset") )
274 setenv("HTTP_ACCEPT_CHARSET", req->headers[i+1], 1);
275
276 else if( ! strcasecmp(req->headers[i], "Accept-Encoding") )
277 setenv("HTTP_ACCEPT_ENCODING", req->headers[i+1], 1);
278
279 else if( ! strcasecmp(req->headers[i], "Accept-Language") )
280 setenv("HTTP_ACCEPT_LANGUAGE", req->headers[i+1], 1);
281
282 else if( ! strcasecmp(req->headers[i], "Authorization") )
283 setenv("HTTP_AUTHORIZATION", req->headers[i+1], 1);
284
285 else if( ! strcasecmp(req->headers[i], "Connection") )
286 setenv("HTTP_CONNECTION", req->headers[i+1], 1);
287
288 else if( ! strcasecmp(req->headers[i], "Cookie") )
289 setenv("HTTP_COOKIE", req->headers[i+1], 1);
290
291 else if( ! strcasecmp(req->headers[i], "Host") )
292 setenv("HTTP_HOST", req->headers[i+1], 1);
293
294 else if( ! strcasecmp(req->headers[i], "Referer") )
295 setenv("HTTP_REFERER", req->headers[i+1], 1);
296
297 else if( ! strcasecmp(req->headers[i], "User-Agent") )
298 setenv("HTTP_USER_AGENT", req->headers[i+1], 1);
299
300 else if( ! strcasecmp(req->headers[i], "Content-Type") )
301 setenv("CONTENT_TYPE", req->headers[i+1], 1);
302
303 else if( ! strcasecmp(req->headers[i], "Content-Length") )
304 setenv("CONTENT_LENGTH", req->headers[i+1], 1);
305 }
306
307
308 /* execute child code ... */
309 if( chdir(pi->root) )
310 perror("chdir()");
311
312 execl(pi->phys, pi->phys, NULL);
313
314 /* in case it fails ... */
315 printf(
316 "Status: 500 Internal Server Error\r\n\r\n"
317 "Unable to launch the requested CGI program:\n"
318 " %s: %s\n",
319 pi->phys, strerror(errno)
320 );
321 }
322
323 /* 403 */
324 else
325 {
326 printf(
327 "Status: 403 Forbidden\r\n\r\n"
328 "Access to this resource is forbidden\n"
329 );
330 }
331
332 close(wfd[0]);
333 close(rfd[1]);
334 exit(0);
335
336 break;
337
338 /* parent; handle I/O relaying */
339 default:
340 /* close unneeded pipe ends */
341 close(rfd[1]);
342 close(wfd[0]);
343
344 /* max watch fd */
345 fd_max = max(rfd[0], wfd[1]) + 1;
346
347 /* find content length */
348 if( req->method == UH_HTTP_MSG_POST )
349 {
350 foreach_header(i, req->headers)
351 {
352 if( ! strcasecmp(req->headers[i], "Content-Length") )
353 {
354 content_length = atoi(req->headers[i+1]);
355 break;
356 }
357 }
358 }
359
360
361 memset(hdr, 0, sizeof(hdr));
362
363 #define ensure(x) \
364 do { if( x < 0 ) goto out; } while(0)
365
366 /* I/O loop, watch our pipe ends and dispatch child reads/writes from/to socket */
367 while( 1 )
368 {
369 FD_ZERO(&reader);
370 FD_ZERO(&writer);
371
372 FD_SET(rfd[0], &reader);
373 FD_SET(wfd[1], &writer);
374
375 timeout.tv_sec = 15;
376 timeout.tv_usec = 0;
377
378 /* wait until we can read or write or both */
379 if( select(fd_max, &reader, (content_length > -1) ? &writer : NULL, NULL, &timeout) > 0 )
380 {
381 /* ready to write to cgi program */
382 if( FD_ISSET(wfd[1], &writer) )
383 {
384 /* there is unread post data waiting */
385 if( content_length > 0 )
386 {
387 /* read it from socket ... */
388 if( (buflen = uh_tcp_recv(cl, buf, min(content_length, sizeof(buf)))) > 0 )
389 {
390 /* ... and write it to child's stdin */
391 if( write(wfd[1], buf, buflen) < 0 )
392 perror("write()");
393
394 content_length -= buflen;
395 }
396
397 /* unexpected eof! */
398 else
399 {
400 if( write(wfd[1], "", 0) < 0 )
401 perror("write()");
402
403 content_length = 0;
404 }
405 }
406
407 /* there is no more post data, close pipe to child's stdin */
408 else if( content_length > -1 )
409 {
410 close(wfd[1]);
411 content_length = -1;
412 }
413 }
414
415 /* ready to read from cgi program */
416 if( FD_ISSET(rfd[0], &reader) )
417 {
418 /* read data from child ... */
419 if( (buflen = read(rfd[0], buf, sizeof(buf))) > 0 )
420 {
421 /* we have not pushed out headers yet, parse input */
422 if( ! header_sent )
423 {
424 /* head buffer not full and no end yet */
425 if( hdrlen < sizeof(hdr) )
426 {
427 bufoff = min(buflen, sizeof(hdr) - hdrlen);
428 memcpy(&hdr[hdrlen], buf, bufoff);
429 hdrlen += bufoff;
430 }
431 else
432 {
433 bufoff = 0;
434 }
435
436
437 /* try to parse header ... */
438 if( (res = uh_cgi_header_parse(hdr, hdrlen, &hdroff)) != NULL )
439 {
440 /* write status */
441 ensure(uh_http_sendf(cl, NULL,
442 "HTTP/%.1f %03d %s\r\n"
443 "Connection: close\r\n",
444 req->version, res->statuscode,
445 res->statusmsg));
446
447 /* add Content-Type if no Location or Content-Type */
448 if( !uh_cgi_header_lookup(res, "Location") &&
449 !uh_cgi_header_lookup(res, "Content-Type")
450 ) {
451 ensure(uh_http_send(cl, NULL,
452 "Content-Type: text/plain\r\n", -1));
453 }
454
455 /* if request was HTTP 1.1 we'll respond chunked */
456 if( (req->version > 1.0) &&
457 !uh_cgi_header_lookup(res, "Transfer-Encoding")
458 ) {
459 ensure(uh_http_send(cl, NULL,
460 "Transfer-Encoding: chunked\r\n", -1));
461 }
462
463 /* write headers from CGI program */
464 foreach_header(i, res->headers)
465 {
466 ensure(uh_http_sendf(cl, NULL, "%s: %s\r\n",
467 res->headers[i], res->headers[i+1]));
468 }
469
470 /* terminate header */
471 ensure(uh_http_send(cl, NULL, "\r\n", -1));
472
473 /* push out remaining head buffer */
474 if( hdroff < hdrlen )
475 ensure(uh_http_send(cl, req, &hdr[hdroff], hdrlen - hdroff));
476 }
477
478 /* ... failed and head buffer exceeded */
479 else if( hdrlen >= sizeof(hdr) )
480 {
481 ensure(uh_cgi_error_500(cl, req,
482 "The CGI program generated an invalid response:\n\n"));
483
484 ensure(uh_http_send(cl, req, hdr, hdrlen));
485 }
486
487 /* ... failed but free buffer space, try again */
488 else
489 {
490 continue;
491 }
492
493 /* push out remaining read buffer */
494 if( bufoff < buflen )
495 ensure(uh_http_send(cl, req, &buf[bufoff], buflen - bufoff));
496
497 header_sent = 1;
498 continue;
499 }
500
501
502 /* headers complete, pass through buffer to socket */
503 ensure(uh_http_send(cl, req, buf, buflen));
504 }
505
506 /* looks like eof from child */
507 else
508 {
509 /* cgi script did not output useful stuff at all */
510 if( ! header_sent )
511 {
512 /* I would do this ...
513 *
514 * uh_cgi_error_500(cl, req,
515 * "The CGI program generated an "
516 * "invalid response:\n\n");
517 *
518 * ... but in order to stay as compatible as possible,
519 * treat whatever we got as text/plain response and
520 * build the required headers here.
521 */
522
523 ensure(uh_http_sendf(cl, NULL,
524 "HTTP/%.1f 200 OK\r\n"
525 "Content-Type: text/plain\r\n"
526 "%s\r\n",
527 req->version, (req->version > 1.0)
528 ? "Transfer-Encoding: chunked\r\n" : ""
529 ));
530
531 ensure(uh_http_send(cl, req, hdr, hdrlen));
532 }
533
534 /* send final chunk if we're in chunked transfer mode */
535 ensure(uh_http_send(cl, req, "", 0));
536 break;
537 }
538 }
539 }
540
541 /* no activity for 15 seconds... looks dead */
542 else
543 {
544 ensure(uh_http_sendhf(cl, 504, "Gateway Timeout",
545 "The CGI script took too long to produce a response"));
546
547 break;
548 }
549 }
550
551 out:
552 close(rfd[0]);
553 close(wfd[1]);
554
555 if( !kill(child, 0) )
556 kill(child, SIGTERM);
557
558 break;
559 }
560 }
561
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