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uhttpd-cgi.c @ 5897

Revision 5897, 13.0 KB (checked in by jow, 3 years ago)
uhttpd: add "Connection: close" headers, mandatory according to HTTP/1.1 spec

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 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	fd_set reader;
154	fd_set writer;
155
156	struct timeval timeout;
157	struct http_response *res;
158
159
160	/* spawn pipes for me->child, child->me */
161	if( (pipe(rfd) < 0) \|\| (pipe(wfd) < 0) )
162	{
163	uh_http_sendhf(cl, 500, "Internal Server Error",
164	"Failed to create pipe: %s", strerror(errno));
165
166	if( rfd[0] > 0 ) close(rfd[0]);
167	if( rfd[1] > 0 ) close(rfd[1]);
168	if( wfd[0] > 0 ) close(wfd[0]);
169	if( wfd[1] > 0 ) close(wfd[1]);
170
171	return;
172	}
173
174	/* fork off child process */
175	switch( fork() )
176	{
177	/* oops */
178	case -1:
179	uh_http_sendhf(cl, 500, "Internal Server Error",
180	"Failed to fork child: %s", strerror(errno));
181	return;
182
183	/* exec child */
184	case 0:
185	/* child */
186	close(rfd[0]);
187	close(wfd[1]);
188
189	/* patch stdout and stdin to pipes */
190	dup2(rfd[1], 1);
191	dup2(wfd[0], 0);
192
193	/* check for regular, world-executable file */
194	if( (pi->stat.st_mode & S_IFREG) &&
195	(pi->stat.st_mode & S_IXOTH)
196	) {
197	/* build environment */
198	clearenv();
199
200	/* common information */
201	setenv("GATEWAY_INTERFACE", "CGI/1.1", 1);
202	setenv("SERVER_SOFTWARE", "uHTTPd", 1);
203	setenv("PATH", "/sbin:/usr/sbin:/bin:/usr/bin", 1);
204
205	#ifdef HAVE_TLS
206	/* https? */
207	if( cl->tls )
208	setenv("HTTPS", "on", 1);
209	#endif
210
211	/* addresses */
212	setenv("SERVER_NAME", sa_straddr(&cl->servaddr), 1);
213	setenv("SERVER_ADDR", sa_straddr(&cl->servaddr), 1);
214	setenv("SERVER_PORT", sa_strport(&cl->servaddr), 1);
215	setenv("REMOTE_HOST", sa_straddr(&cl->peeraddr), 1);
216	setenv("REMOTE_ADDR", sa_straddr(&cl->peeraddr), 1);
217	setenv("REMOTE_PORT", sa_strport(&cl->peeraddr), 1);
218
219	/* path information */
220	setenv("SCRIPT_NAME", pi->name, 1);
221	setenv("SCRIPT_FILENAME", pi->phys, 1);
222	setenv("DOCUMENT_ROOT", pi->root, 1);
223	setenv("QUERY_STRING", pi->query ? pi->query : "", 1);
224
225	if( pi->info )
226	setenv("PATH_INFO", pi->info, 1);
227
228
229	/* http version */
230	if( req->version > 1.0 )
231	setenv("SERVER_PROTOCOL", "HTTP/1.1", 1);
232	else
233	setenv("SERVER_PROTOCOL", "HTTP/1.0", 1);
234
235	/* request method */
236	switch( req->method )
237	{
238	case UH_HTTP_MSG_GET:
239	setenv("REQUEST_METHOD", "GET", 1);
240	break;
241
242	case UH_HTTP_MSG_HEAD:
243	setenv("REQUEST_METHOD", "HEAD", 1);
244	break;
245
246	case UH_HTTP_MSG_POST:
247	setenv("REQUEST_METHOD", "POST", 1);
248	break;
249	}
250
251	/* request url */
252	setenv("REQUEST_URI", req->url, 1);
253
254	/* remote user */
255	if( req->realm )
256	setenv("REMOTE_USER", req->realm->user, 1);
257
258	/* request message headers */
259	foreach_header(i, req->headers)
260	{
261	if( ! strcasecmp(req->headers[i], "Accept") )
262	setenv("HTTP_ACCEPT", req->headers[i+1], 1);
263
264	else if( ! strcasecmp(req->headers[i], "Accept-Charset") )
265	setenv("HTTP_ACCEPT_CHARSET", req->headers[i+1], 1);
266
267	else if( ! strcasecmp(req->headers[i], "Accept-Encoding") )
268	setenv("HTTP_ACCEPT_ENCODING", req->headers[i+1], 1);
269
270	else if( ! strcasecmp(req->headers[i], "Accept-Language") )
271	setenv("HTTP_ACCEPT_LANGUAGE", req->headers[i+1], 1);
272
273	else if( ! strcasecmp(req->headers[i], "Authorization") )
274	setenv("HTTP_AUTHORIZATION", req->headers[i+1], 1);
275
276	else if( ! strcasecmp(req->headers[i], "Connection") )
277	setenv("HTTP_CONNECTION", req->headers[i+1], 1);
278
279	else if( ! strcasecmp(req->headers[i], "Cookie") )
280	setenv("HTTP_COOKIE", req->headers[i+1], 1);
281
282	else if( ! strcasecmp(req->headers[i], "Host") )
283	setenv("HTTP_HOST", req->headers[i+1], 1);
284
285	else if( ! strcasecmp(req->headers[i], "Referer") )
286	setenv("HTTP_REFERER", req->headers[i+1], 1);
287
288	else if( ! strcasecmp(req->headers[i], "User-Agent") )
289	setenv("HTTP_USER_AGENT", req->headers[i+1], 1);
290
291	else if( ! strcasecmp(req->headers[i], "Content-Type") )
292	setenv("CONTENT_TYPE", req->headers[i+1], 1);
293
294	else if( ! strcasecmp(req->headers[i], "Content-Length") )
295	setenv("CONTENT_LENGTH", req->headers[i+1], 1);
296	}
297
298
299	/* execute child code ... */
300	if( chdir(pi->root) )
301	perror("chdir()");
302
303	execl(pi->phys, pi->phys, NULL);
304
305	/* in case it fails ... */
306	printf(
307	"Status: 500 Internal Server Error\r\n\r\n"
308	"Unable to launch the requested CGI program:\n"
309	" %s: %s\n",
310	pi->phys, strerror(errno)
311	);
312	}
313
314	/* 403 */
315	else
316	{
317	printf(
318	"Status: 403 Forbidden\r\n\r\n"
319	"Access to this resource is forbidden\n"
320	);
321	}
322
323	close(wfd[0]);
324	close(rfd[1]);
325	exit(0);
326
327	break;
328
329	/* parent; handle I/O relaying */
330	default:
331	/* close unneeded pipe ends */
332	close(rfd[1]);
333	close(wfd[0]);
334
335	/* max watch fd */
336	fd_max = max(rfd[0], wfd[1]) + 1;
337
338	/* find content length */
339	if( req->method == UH_HTTP_MSG_POST )
340	{
341	foreach_header(i, req->headers)
342	{
343	if( ! strcasecmp(req->headers[i], "Content-Length") )
344	{
345	content_length = atoi(req->headers[i+1]);
346	break;
347	}
348	}
349	}
350
351
352	memset(hdr, 0, sizeof(hdr));
353
354	#define ensure(x) \
355	do { if( x < 0 ) goto out; } while(0)
356
357	/* I/O loop, watch our pipe ends and dispatch child reads/writes from/to socket */
358	while( 1 )
359	{
360	FD_ZERO(&reader);
361	FD_ZERO(&writer);
362
363	FD_SET(rfd[0], &reader);
364	FD_SET(wfd[1], &writer);
365
366	timeout.tv_sec = 15;
367	timeout.tv_usec = 0;
368
369	/* wait until we can read or write or both */
370	if( select(fd_max, &reader, (content_length > -1) ? &writer : NULL, NULL, &timeout) > 0 )
371	{
372	/* ready to write to cgi program */
373	if( FD_ISSET(wfd[1], &writer) )
374	{
375	/* there is unread post data waiting */
376	if( content_length > 0 )
377	{
378	/* read it from socket ... */
379	if( (buflen = uh_tcp_recv(cl, buf, min(content_length, sizeof(buf)))) > 0 )
380	{
381	/* ... and write it to child's stdin */
382	if( write(wfd[1], buf, buflen) < 0 )
383	perror("write()");
384
385	content_length -= buflen;
386	}
387
388	/* unexpected eof! */
389	else
390	{
391	if( write(wfd[1], "", 0) < 0 )
392	perror("write()");
393
394	content_length = 0;
395	}
396	}
397
398	/* there is no more post data, close pipe to child's stdin */
399	else if( content_length > -1 )
400	{
401	close(wfd[1]);
402	content_length = -1;
403	}
404	}
405
406	/* ready to read from cgi program */
407	if( FD_ISSET(rfd[0], &reader) )
408	{
409	/* read data from child ... */
410	if( (buflen = read(rfd[0], buf, sizeof(buf))) > 0 )
411	{
412	/* we have not pushed out headers yet, parse input */
413	if( ! header_sent )
414	{
415	/* head buffer not full and no end yet */
416	if( hdrlen < sizeof(hdr) )
417	{
418	bufoff = min(buflen, sizeof(hdr) - hdrlen);
419	memcpy(&hdr[hdrlen], buf, bufoff);
420	hdrlen += bufoff;
421	}
422	else
423	{
424	bufoff = 0;
425	}
426
427
428	/* try to parse header ... */
429	if( (res = uh_cgi_header_parse(hdr, hdrlen, &hdroff)) != NULL )
430	{
431	/* write status */
432	ensure(uh_http_sendf(cl, NULL,
433	"HTTP/%.1f %03d %s\r\n"
434	"Connection: close\r\n",
435	req->version, res->statuscode,
436	res->statusmsg));
437
438	/* add Content-Type if no Location or Content-Type */
439	if( !uh_cgi_header_lookup(res, "Location") &&
440	!uh_cgi_header_lookup(res, "Content-Type")
441	) {
442	ensure(uh_http_send(cl, NULL,
443	"Content-Type: text/plain\r\n", -1));
444	}
445
446	/* if request was HTTP 1.1 we'll respond chunked */
447	if( (req->version > 1.0) &&
448	!uh_cgi_header_lookup(res, "Transfer-Encoding")
449	) {
450	ensure(uh_http_send(cl, NULL,
451	"Transfer-Encoding: chunked\r\n", -1));
452	}
453
454	/* write headers from CGI program */
455	foreach_header(i, res->headers)
456	{
457	ensure(uh_http_sendf(cl, NULL, "%s: %s\r\n",
458	res->headers[i], res->headers[i+1]));
459	}
460
461	/* terminate header */
462	ensure(uh_http_send(cl, NULL, "\r\n", -1));
463
464	/* push out remaining head buffer */
465	if( hdroff < hdrlen )
466	ensure(uh_http_send(cl, req, &hdr[hdroff], hdrlen - hdroff));
467	}
468
469	/* ... failed and head buffer exceeded */
470	else if( hdrlen >= sizeof(hdr) )
471	{
472	ensure(uh_cgi_error_500(cl, req,
473	"The CGI program generated an invalid response:\n\n"));
474
475	ensure(uh_http_send(cl, req, hdr, hdrlen));
476	}
477
478	/* ... failed but free buffer space, try again */
479	else
480	{
481	continue;
482	}
483
484	/* push out remaining read buffer */
485	if( bufoff < buflen )
486	ensure(uh_http_send(cl, req, &buf[bufoff], buflen - bufoff));
487
488	header_sent = 1;
489	continue;
490	}
491
492
493	/* headers complete, pass through buffer to socket */
494	ensure(uh_http_send(cl, req, buf, buflen));
495	}
496
497	/* looks like eof from child */
498	else
499	{
500	/* cgi script did not output useful stuff at all */
501	if( ! header_sent )
502	{
503	/* I would do this ...
504	*
505	* uh_cgi_error_500(cl, req,
506	* "The CGI program generated an "
507	* "invalid response:\n\n");
508	*
509	* ... but in order to stay as compatible as possible,
510	* treat whatever we got as text/plain response and
511	* build the required headers here.
512	*/
513
514	ensure(uh_http_sendf(cl, NULL,
515	"HTTP/%.1f 200 OK\r\n"
516	"Content-Type: text/plain\r\n"
517	"%s\r\n",
518	req->version, (req->version > 1.0)
519	? "Transfer-Encoding: chunked\r\n" : ""
520	));
521
522	ensure(uh_http_send(cl, req, hdr, hdrlen));
523	}
524
525	/* send final chunk if we're in chunked transfer mode */
526	ensure(uh_http_send(cl, req, "", 0));
527	break;
528	}
529	}
530	}
531
532	/* no activity for 15 seconds... looks dead */
533	else
534	{
535	ensure(uh_http_sendhf(cl, 504, "Gateway Timeout",
536	"The CGI script took too long to produce a response"));
537
538	break;
539	}
540	}
541
542	out:
543	close(rfd[0]);
544	close(wfd[1]);
545
546	break;
547	}
548	}
549

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