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uhttpd-cgi.c @ 5894

Revision 5894, 12.7 KB (checked in by jow, 3 years ago)
uhttpd: relax cgi timeout

Line
1	/*
2	* uhttpd - Tiny non-forking 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 void uh_cgi_error_500(struct client cl, struct http_request req, const char *message)
122	{
123	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	);
130
131	uh_http_send(cl, req, message, -1);
132	}
133
134
135	void uh_cgi_request(struct client cl, struct http_request req, struct path_info *pi)
136	{
137	int i, hdroff, bufoff;
138	int hdrlen = 0;
139	int buflen = 0;
140	int fd_max = 0;
141	int content_length = 0;
142	int header_sent = 0;
143
144	int rfd[2] = { 0, 0 };
145	int wfd[2] = { 0, 0 };
146
147	char buf[UH_LIMIT_MSGHEAD];
148	char hdr[UH_LIMIT_MSGHEAD];
149
150	fd_set reader;
151	fd_set writer;
152
153	struct timeval timeout;
154	struct http_response *res;
155
156
157	/* spawn pipes for me->child, child->me */
158	if( (pipe(rfd) < 0) \|\| (pipe(wfd) < 0) )
159	{
160	uh_http_sendhf(cl, 500, "Internal Server Error",
161	"Failed to create pipe: %s", strerror(errno));
162
163	if( rfd[0] > 0 ) close(rfd[0]);
164	if( rfd[1] > 0 ) close(rfd[1]);
165	if( wfd[0] > 0 ) close(wfd[0]);
166	if( wfd[1] > 0 ) close(wfd[1]);
167
168	return;
169	}
170
171	/* fork off child process */
172	switch( fork() )
173	{
174	/* oops */
175	case -1:
176	uh_http_sendhf(cl, 500, "Internal Server Error",
177	"Failed to fork child: %s", strerror(errno));
178	return;
179
180	/* exec child */
181	case 0:
182	/* child */
183	close(rfd[0]);
184	close(wfd[1]);
185
186	/* patch stdout and stdin to pipes */
187	dup2(rfd[1], 1);
188	dup2(wfd[0], 0);
189
190	/* check for regular, world-executable file */
191	if( (pi->stat.st_mode & S_IFREG) &&
192	(pi->stat.st_mode & S_IXOTH)
193	) {
194	/* build environment */
195	clearenv();
196
197	/* common information */
198	setenv("GATEWAY_INTERFACE", "CGI/1.1", 1);
199	setenv("SERVER_SOFTWARE", "uHTTPd", 1);
200	setenv("PATH", "/sbin:/usr/sbin:/bin:/usr/bin", 1);
201
202	#ifdef HAVE_TLS
203	/* https? */
204	if( cl->tls )
205	setenv("HTTPS", "on", 1);
206	#endif
207
208	/* addresses */
209	setenv("SERVER_NAME", sa_straddr(&cl->servaddr), 1);
210	setenv("SERVER_ADDR", sa_straddr(&cl->servaddr), 1);
211	setenv("SERVER_PORT", sa_strport(&cl->servaddr), 1);
212	setenv("REMOTE_HOST", sa_straddr(&cl->peeraddr), 1);
213	setenv("REMOTE_ADDR", sa_straddr(&cl->peeraddr), 1);
214	setenv("REMOTE_PORT", sa_strport(&cl->peeraddr), 1);
215
216	/* path information */
217	setenv("SCRIPT_NAME", pi->name, 1);
218	setenv("SCRIPT_FILENAME", pi->phys, 1);
219	setenv("DOCUMENT_ROOT", pi->root, 1);
220	setenv("QUERY_STRING", pi->query ? pi->query : "", 1);
221
222	if( pi->info )
223	setenv("PATH_INFO", pi->info, 1);
224
225
226	/* http version */
227	if( req->version > 1.0 )
228	setenv("SERVER_PROTOCOL", "HTTP/1.1", 1);
229	else
230	setenv("SERVER_PROTOCOL", "HTTP/1.0", 1);
231
232	/* request method */
233	switch( req->method )
234	{
235	case UH_HTTP_MSG_GET:
236	setenv("REQUEST_METHOD", "GET", 1);
237	break;
238
239	case UH_HTTP_MSG_HEAD:
240	setenv("REQUEST_METHOD", "HEAD", 1);
241	break;
242
243	case UH_HTTP_MSG_POST:
244	setenv("REQUEST_METHOD", "POST", 1);
245	break;
246	}
247
248	/* request url */
249	setenv("REQUEST_URI", req->url, 1);
250
251	/* remote user */
252	if( req->realm )
253	setenv("REMOTE_USER", req->realm->user, 1);
254
255	/* request message headers */
256	foreach_header(i, req->headers)
257	{
258	if( ! strcasecmp(req->headers[i], "Accept") )
259	setenv("HTTP_ACCEPT", req->headers[i+1], 1);
260
261	else if( ! strcasecmp(req->headers[i], "Accept-Charset") )
262	setenv("HTTP_ACCEPT_CHARSET", req->headers[i+1], 1);
263
264	else if( ! strcasecmp(req->headers[i], "Accept-Encoding") )
265	setenv("HTTP_ACCEPT_ENCODING", req->headers[i+1], 1);
266
267	else if( ! strcasecmp(req->headers[i], "Accept-Language") )
268	setenv("HTTP_ACCEPT_LANGUAGE", req->headers[i+1], 1);
269
270	else if( ! strcasecmp(req->headers[i], "Authorization") )
271	setenv("HTTP_AUTHORIZATION", req->headers[i+1], 1);
272
273	else if( ! strcasecmp(req->headers[i], "Connection") )
274	setenv("HTTP_CONNECTION", req->headers[i+1], 1);
275
276	else if( ! strcasecmp(req->headers[i], "Cookie") )
277	setenv("HTTP_COOKIE", req->headers[i+1], 1);
278
279	else if( ! strcasecmp(req->headers[i], "Host") )
280	setenv("HTTP_HOST", req->headers[i+1], 1);
281
282	else if( ! strcasecmp(req->headers[i], "Referer") )
283	setenv("HTTP_REFERER", req->headers[i+1], 1);
284
285	else if( ! strcasecmp(req->headers[i], "User-Agent") )
286	setenv("HTTP_USER_AGENT", req->headers[i+1], 1);
287
288	else if( ! strcasecmp(req->headers[i], "Content-Type") )
289	setenv("CONTENT_TYPE", req->headers[i+1], 1);
290
291	else if( ! strcasecmp(req->headers[i], "Content-Length") )
292	setenv("CONTENT_LENGTH", req->headers[i+1], 1);
293	}
294
295
296	/* execute child code ... */
297	if( chdir(pi->root) )
298	perror("chdir()");
299
300	execl(pi->phys, pi->phys, NULL);
301
302	/* in case it fails ... */
303	printf(
304	"Status: 500 Internal Server Error\r\n\r\n"
305	"Unable to launch the requested CGI program:\n"
306	" %s: %s\n",
307	pi->phys, strerror(errno)
308	);
309	}
310
311	/* 403 */
312	else
313	{
314	printf(
315	"Status: 403 Forbidden\r\n\r\n"
316	"Access to this resource is forbidden\n"
317	);
318	}
319
320	close(wfd[0]);
321	close(rfd[1]);
322	exit(0);
323
324	break;
325
326	/* parent; handle I/O relaying */
327	default:
328	/* close unneeded pipe ends */
329	close(rfd[1]);
330	close(wfd[0]);
331
332	/* max watch fd */
333	fd_max = max(rfd[0], wfd[1]) + 1;
334
335	/* find content length */
336	if( req->method == UH_HTTP_MSG_POST )
337	{
338	foreach_header(i, req->headers)
339	{
340	if( ! strcasecmp(req->headers[i], "Content-Length") )
341	{
342	content_length = atoi(req->headers[i+1]);
343	break;
344	}
345	}
346	}
347
348
349	memset(hdr, 0, sizeof(hdr));
350
351	/* I/O loop, watch our pipe ends and dispatch child reads/writes from/to socket */
352	while( 1 )
353	{
354	FD_ZERO(&reader);
355	FD_ZERO(&writer);
356
357	FD_SET(rfd[0], &reader);
358	FD_SET(wfd[1], &writer);
359
360	timeout.tv_sec = 15;
361	timeout.tv_usec = 0;
362
363	/* wait until we can read or write or both */
364	if( select(fd_max, &reader, (content_length > -1) ? &writer : NULL, NULL, &timeout) > 0 )
365	{
366	/* ready to write to cgi program */
367	if( FD_ISSET(wfd[1], &writer) )
368	{
369	/* there is unread post data waiting */
370	if( content_length > 0 )
371	{
372	/* read it from socket ... */
373	if( (buflen = uh_tcp_recv(cl, buf, min(content_length, sizeof(buf)))) > 0 )
374	{
375	/* ... and write it to child's stdin */
376	if( write(wfd[1], buf, buflen) < 0 )
377	perror("write()");
378
379	content_length -= buflen;
380	}
381
382	/* unexpected eof! */
383	else
384	{
385	if( write(wfd[1], "", 0) < 0 )
386	perror("write()");
387
388	content_length = 0;
389	}
390	}
391
392	/* there is no more post data, close pipe to child's stdin */
393	else
394	{
395	close(wfd[1]);
396	content_length = -1;
397	}
398	}
399
400	/* ready to read from cgi program */
401	if( FD_ISSET(rfd[0], &reader) )
402	{
403	/* read data from child ... */
404	if( (buflen = read(rfd[0], buf, sizeof(buf))) > 0 )
405	{
406	/* we have not pushed out headers yet, parse input */
407	if( ! header_sent )
408	{
409	/* head buffer not full and no end yet */
410	if( hdrlen < sizeof(hdr) )
411	{
412	bufoff = min(buflen, sizeof(hdr) - hdrlen);
413	memcpy(&hdr[hdrlen], buf, bufoff);
414	hdrlen += bufoff;
415	}
416	else
417	{
418	bufoff = 0;
419	}
420
421
422	/* try to parse header ... */
423	if( (res = uh_cgi_header_parse(hdr, hdrlen, &hdroff)) != NULL )
424	{
425	/* write status */
426	uh_http_sendf(cl, NULL, "HTTP/%.1f %03d %s\r\n",
427	req->version, res->statuscode, res->statusmsg);
428
429	/* add Content-Type if no Location or Content-Type */
430	if( !uh_cgi_header_lookup(res, "Location") &&
431	!uh_cgi_header_lookup(res, "Content-Type")
432	) {
433	uh_http_send(cl, NULL,
434	"Content-Type: text/plain\r\n", -1);
435	}
436
437	/* if request was HTTP 1.1 we'll respond chunked */
438	if( (req->version > 1.0) &&
439	!uh_cgi_header_lookup(res, "Transfer-Encoding")
440	) {
441	uh_http_send(cl, NULL,
442	"Transfer-Encoding: chunked\r\n", -1);
443	}
444
445	/* write headers from CGI program */
446	foreach_header(i, res->headers)
447	{
448	uh_http_sendf(cl, NULL, "%s: %s\r\n",
449	res->headers[i], res->headers[i+1]);
450	}
451
452	/* terminate header */
453	uh_http_send(cl, NULL, "\r\n", -1);
454
455	/* push out remaining head buffer */
456	if( hdroff < hdrlen )
457	uh_http_send(cl, req, &hdr[hdroff], hdrlen - hdroff);
458	}
459
460	/* ... failed and head buffer exceeded */
461	else if( hdrlen >= sizeof(hdr) )
462	{
463	uh_cgi_error_500(cl, req,
464	"The CGI program generated an invalid response:\n\n");
465
466	uh_http_send(cl, req, hdr, hdrlen);
467	}
468
469	/* ... failed but free buffer space, try again */
470	else
471	{
472	continue;
473	}
474
475	/* push out remaining read buffer */
476	if( bufoff < buflen )
477	uh_http_send(cl, req, &buf[bufoff], buflen - bufoff);
478
479	header_sent = 1;
480	continue;
481	}
482
483
484	/* headers complete, pass through buffer to socket */
485	uh_http_send(cl, req, buf, buflen);
486	}
487
488	/* looks like eof from child */
489	else
490	{
491	/* cgi script did not output useful stuff at all */
492	if( ! header_sent )
493	{
494	/* I would do this ...
495	*
496	* uh_cgi_error_500(cl, req,
497	* "The CGI program generated an "
498	* "invalid response:\n\n");
499	*
500	* ... but in order to stay as compatible as possible,
501	* treat whatever we got as text/plain response and
502	* build the required headers here.
503	*/
504
505	uh_http_sendf(cl, NULL,
506	"HTTP/%.1f 200 OK\r\n"
507	"Content-Type: text/plain\r\n"
508	"%s\r\n",
509	req->version, (req->version > 1.0)
510	? "Transfer-Encoding: chunked\r\n" : ""
511	);
512
513	uh_http_send(cl, req, hdr, hdrlen);
514	}
515
516	/* send final chunk if we're in chunked transfer mode */
517	uh_http_send(cl, req, "", 0);
518	break;
519	}
520	}
521	}
522
523	/* no activity for 15 seconds... looks dead */
524	else
525	{
526	uh_http_sendhf(cl, 504, "Gateway Timeout",
527	"The CGI script took too long to produce a response");
528
529	break;
530	}
531	}
532
533	close(rfd[0]);
534	close(wfd[1]);
535
536	break;
537	}
538	}
539

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