xref: /freebsd/lib/libfetch/http.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
1 /*-
2  * Copyright (c) 2000-2004 Dag-Erling Co�dan Sm�rgrav
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer
10  *    in this position and unchanged.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. The name of the author may not be used to endorse or promote products
15  *    derived from this software without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 /*
33  * The following copyright applies to the base64 code:
34  *
35  *-
36  * Copyright 1997 Massachusetts Institute of Technology
37  *
38  * Permission to use, copy, modify, and distribute this software and
39  * its documentation for any purpose and without fee is hereby
40  * granted, provided that both the above copyright notice and this
41  * permission notice appear in all copies, that both the above
42  * copyright notice and this permission notice appear in all
43  * supporting documentation, and that the name of M.I.T. not be used
44  * in advertising or publicity pertaining to distribution of the
45  * software without specific, written prior permission.  M.I.T. makes
46  * no representations about the suitability of this software for any
47  * purpose.  It is provided "as is" without express or implied
48  * warranty.
49  *
50  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
51  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
52  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
53  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
54  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
55  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
56  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
57  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
58  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
59  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
60  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
61  * SUCH DAMAGE.
62  */
63 
64 #include <sys/param.h>
65 #include <sys/socket.h>
66 
67 #include <ctype.h>
68 #include <err.h>
69 #include <errno.h>
70 #include <locale.h>
71 #include <netdb.h>
72 #include <stdarg.h>
73 #include <stdio.h>
74 #include <stdlib.h>
75 #include <string.h>
76 #include <time.h>
77 #include <unistd.h>
78 
79 #include <netinet/in.h>
80 #include <netinet/tcp.h>
81 
82 #include "fetch.h"
83 #include "common.h"
84 #include "httperr.h"
85 
86 /* Maximum number of redirects to follow */
87 #define MAX_REDIRECT 5
88 
89 /* Symbolic names for reply codes we care about */
90 #define HTTP_OK			200
91 #define HTTP_PARTIAL		206
92 #define HTTP_MOVED_PERM		301
93 #define HTTP_MOVED_TEMP		302
94 #define HTTP_SEE_OTHER		303
95 #define HTTP_TEMP_REDIRECT	307
96 #define HTTP_NEED_AUTH		401
97 #define HTTP_NEED_PROXY_AUTH	407
98 #define HTTP_BAD_RANGE		416
99 #define HTTP_PROTOCOL_ERROR	999
100 
101 #define HTTP_REDIRECT(xyz) ((xyz) == HTTP_MOVED_PERM \
102 			    || (xyz) == HTTP_MOVED_TEMP \
103 			    || (xyz) == HTTP_TEMP_REDIRECT \
104 			    || (xyz) == HTTP_SEE_OTHER)
105 
106 #define HTTP_ERROR(xyz) ((xyz) > 400 && (xyz) < 599)
107 
108 
109 /*****************************************************************************
110  * I/O functions for decoding chunked streams
111  */
112 
113 struct httpio
114 {
115 	conn_t		*conn;		/* connection */
116 	int		 chunked;	/* chunked mode */
117 	char		*buf;		/* chunk buffer */
118 	size_t		 bufsize;	/* size of chunk buffer */
119 	ssize_t		 buflen;	/* amount of data currently in buffer */
120 	int		 bufpos;	/* current read offset in buffer */
121 	int		 eof;		/* end-of-file flag */
122 	int		 error;		/* error flag */
123 	size_t		 chunksize;	/* remaining size of current chunk */
124 #ifndef NDEBUG
125 	size_t		 total;
126 #endif
127 };
128 
129 /*
130  * Get next chunk header
131  */
132 static int
133 http_new_chunk(struct httpio *io)
134 {
135 	char *p;
136 
137 	if (fetch_getln(io->conn) == -1)
138 		return (-1);
139 
140 	if (io->conn->buflen < 2 || !isxdigit((unsigned char)*io->conn->buf))
141 		return (-1);
142 
143 	for (p = io->conn->buf; *p && !isspace((unsigned char)*p); ++p) {
144 		if (*p == ';')
145 			break;
146 		if (!isxdigit((unsigned char)*p))
147 			return (-1);
148 		if (isdigit((unsigned char)*p)) {
149 			io->chunksize = io->chunksize * 16 +
150 			    *p - '0';
151 		} else {
152 			io->chunksize = io->chunksize * 16 +
153 			    10 + tolower(*p) - 'a';
154 		}
155 	}
156 
157 #ifndef NDEBUG
158 	if (fetchDebug) {
159 		io->total += io->chunksize;
160 		if (io->chunksize == 0)
161 			fprintf(stderr, "%s(): end of last chunk\n", __func__);
162 		else
163 			fprintf(stderr, "%s(): new chunk: %lu (%lu)\n",
164 			    __func__, (unsigned long)io->chunksize,
165 			    (unsigned long)io->total);
166 	}
167 #endif
168 
169 	return (io->chunksize);
170 }
171 
172 /*
173  * Grow the input buffer to at least len bytes
174  */
175 static inline int
176 http_growbuf(struct httpio *io, size_t len)
177 {
178 	char *tmp;
179 
180 	if (io->bufsize >= len)
181 		return (0);
182 
183 	if ((tmp = realloc(io->buf, len)) == NULL)
184 		return (-1);
185 	io->buf = tmp;
186 	io->bufsize = len;
187 	return (0);
188 }
189 
190 /*
191  * Fill the input buffer, do chunk decoding on the fly
192  */
193 static int
194 http_fillbuf(struct httpio *io, size_t len)
195 {
196 	if (io->error)
197 		return (-1);
198 	if (io->eof)
199 		return (0);
200 
201 	if (io->chunked == 0) {
202 		if (http_growbuf(io, len) == -1)
203 			return (-1);
204 		if ((io->buflen = fetch_read(io->conn, io->buf, len)) == -1) {
205 			io->error = 1;
206 			return (-1);
207 		}
208 		io->bufpos = 0;
209 		return (io->buflen);
210 	}
211 
212 	if (io->chunksize == 0) {
213 		switch (http_new_chunk(io)) {
214 		case -1:
215 			io->error = 1;
216 			return (-1);
217 		case 0:
218 			io->eof = 1;
219 			return (0);
220 		}
221 	}
222 
223 	if (len > io->chunksize)
224 		len = io->chunksize;
225 	if (http_growbuf(io, len) == -1)
226 		return (-1);
227 	if ((io->buflen = fetch_read(io->conn, io->buf, len)) == -1) {
228 		io->error = 1;
229 		return (-1);
230 	}
231 	io->chunksize -= io->buflen;
232 
233 	if (io->chunksize == 0) {
234 		char endl[2];
235 
236 		if (fetch_read(io->conn, endl, 2) != 2 ||
237 		    endl[0] != '\r' || endl[1] != '\n')
238 			return (-1);
239 	}
240 
241 	io->bufpos = 0;
242 
243 	return (io->buflen);
244 }
245 
246 /*
247  * Read function
248  */
249 static int
250 http_readfn(void *v, char *buf, int len)
251 {
252 	struct httpio *io = (struct httpio *)v;
253 	int l, pos;
254 
255 	if (io->error)
256 		return (-1);
257 	if (io->eof)
258 		return (0);
259 
260 	for (pos = 0; len > 0; pos += l, len -= l) {
261 		/* empty buffer */
262 		if (!io->buf || io->bufpos == io->buflen)
263 			if (http_fillbuf(io, len) < 1)
264 				break;
265 		l = io->buflen - io->bufpos;
266 		if (len < l)
267 			l = len;
268 		bcopy(io->buf + io->bufpos, buf + pos, l);
269 		io->bufpos += l;
270 	}
271 
272 	if (!pos && io->error)
273 		return (-1);
274 	return (pos);
275 }
276 
277 /*
278  * Write function
279  */
280 static int
281 http_writefn(void *v, const char *buf, int len)
282 {
283 	struct httpio *io = (struct httpio *)v;
284 
285 	return (fetch_write(io->conn, buf, len));
286 }
287 
288 /*
289  * Close function
290  */
291 static int
292 http_closefn(void *v)
293 {
294 	struct httpio *io = (struct httpio *)v;
295 	int r;
296 
297 	r = fetch_close(io->conn);
298 	if (io->buf)
299 		free(io->buf);
300 	free(io);
301 	return (r);
302 }
303 
304 /*
305  * Wrap a file descriptor up
306  */
307 static FILE *
308 http_funopen(conn_t *conn, int chunked)
309 {
310 	struct httpio *io;
311 	FILE *f;
312 
313 	if ((io = calloc(1, sizeof(*io))) == NULL) {
314 		fetch_syserr();
315 		return (NULL);
316 	}
317 	io->conn = conn;
318 	io->chunked = chunked;
319 	f = funopen(io, http_readfn, http_writefn, NULL, http_closefn);
320 	if (f == NULL) {
321 		fetch_syserr();
322 		free(io);
323 		return (NULL);
324 	}
325 	return (f);
326 }
327 
328 
329 /*****************************************************************************
330  * Helper functions for talking to the server and parsing its replies
331  */
332 
333 /* Header types */
334 typedef enum {
335 	hdr_syserror = -2,
336 	hdr_error = -1,
337 	hdr_end = 0,
338 	hdr_unknown = 1,
339 	hdr_content_length,
340 	hdr_content_range,
341 	hdr_last_modified,
342 	hdr_location,
343 	hdr_transfer_encoding,
344 	hdr_www_authenticate
345 } hdr_t;
346 
347 /* Names of interesting headers */
348 static struct {
349 	hdr_t		 num;
350 	const char	*name;
351 } hdr_names[] = {
352 	{ hdr_content_length,		"Content-Length" },
353 	{ hdr_content_range,		"Content-Range" },
354 	{ hdr_last_modified,		"Last-Modified" },
355 	{ hdr_location,			"Location" },
356 	{ hdr_transfer_encoding,	"Transfer-Encoding" },
357 	{ hdr_www_authenticate,		"WWW-Authenticate" },
358 	{ hdr_unknown,			NULL },
359 };
360 
361 /*
362  * Send a formatted line; optionally echo to terminal
363  */
364 static int
365 http_cmd(conn_t *conn, const char *fmt, ...)
366 {
367 	va_list ap;
368 	size_t len;
369 	char *msg;
370 	int r;
371 
372 	va_start(ap, fmt);
373 	len = vasprintf(&msg, fmt, ap);
374 	va_end(ap);
375 
376 	if (msg == NULL) {
377 		errno = ENOMEM;
378 		fetch_syserr();
379 		return (-1);
380 	}
381 
382 	r = fetch_putln(conn, msg, len);
383 	free(msg);
384 
385 	if (r == -1) {
386 		fetch_syserr();
387 		return (-1);
388 	}
389 
390 	return (0);
391 }
392 
393 /*
394  * Get and parse status line
395  */
396 static int
397 http_get_reply(conn_t *conn)
398 {
399 	char *p;
400 
401 	if (fetch_getln(conn) == -1)
402 		return (-1);
403 	/*
404 	 * A valid status line looks like "HTTP/m.n xyz reason" where m
405 	 * and n are the major and minor protocol version numbers and xyz
406 	 * is the reply code.
407 	 * Unfortunately, there are servers out there (NCSA 1.5.1, to name
408 	 * just one) that do not send a version number, so we can't rely
409 	 * on finding one, but if we do, insist on it being 1.0 or 1.1.
410 	 * We don't care about the reason phrase.
411 	 */
412 	if (strncmp(conn->buf, "HTTP", 4) != 0)
413 		return (HTTP_PROTOCOL_ERROR);
414 	p = conn->buf + 4;
415 	if (*p == '/') {
416 		if (p[1] != '1' || p[2] != '.' || (p[3] != '0' && p[3] != '1'))
417 			return (HTTP_PROTOCOL_ERROR);
418 		p += 4;
419 	}
420 	if (*p != ' ' ||
421 	    !isdigit((unsigned char)p[1]) ||
422 	    !isdigit((unsigned char)p[2]) ||
423 	    !isdigit((unsigned char)p[3]))
424 		return (HTTP_PROTOCOL_ERROR);
425 
426 	conn->err = (p[1] - '0') * 100 + (p[2] - '0') * 10 + (p[3] - '0');
427 	return (conn->err);
428 }
429 
430 /*
431  * Check a header; if the type matches the given string, return a pointer
432  * to the beginning of the value.
433  */
434 static const char *
435 http_match(const char *str, const char *hdr)
436 {
437 	while (*str && *hdr && tolower(*str++) == tolower(*hdr++))
438 		/* nothing */;
439 	if (*str || *hdr != ':')
440 		return (NULL);
441 	while (*hdr && isspace((unsigned char)*++hdr))
442 		/* nothing */;
443 	return (hdr);
444 }
445 
446 /*
447  * Get the next header and return the appropriate symbolic code.
448  */
449 static hdr_t
450 http_next_header(conn_t *conn, const char **p)
451 {
452 	int i;
453 
454 	if (fetch_getln(conn) == -1)
455 		return (hdr_syserror);
456 	while (conn->buflen && isspace((unsigned char)conn->buf[conn->buflen - 1]))
457 		conn->buflen--;
458 	conn->buf[conn->buflen] = '\0';
459 	if (conn->buflen == 0)
460 		return (hdr_end);
461 	/*
462 	 * We could check for malformed headers but we don't really care.
463 	 * A valid header starts with a token immediately followed by a
464 	 * colon; a token is any sequence of non-control, non-whitespace
465 	 * characters except "()<>@,;:\\\"{}".
466 	 */
467 	for (i = 0; hdr_names[i].num != hdr_unknown; i++)
468 		if ((*p = http_match(hdr_names[i].name, conn->buf)) != NULL)
469 			return (hdr_names[i].num);
470 	return (hdr_unknown);
471 }
472 
473 /*
474  * Parse a last-modified header
475  */
476 static int
477 http_parse_mtime(const char *p, time_t *mtime)
478 {
479 	char locale[64], *r;
480 	struct tm tm;
481 
482 	strncpy(locale, setlocale(LC_TIME, NULL), sizeof(locale));
483 	setlocale(LC_TIME, "C");
484 	r = strptime(p, "%a, %d %b %Y %H:%M:%S GMT", &tm);
485 	/* XXX should add support for date-2 and date-3 */
486 	setlocale(LC_TIME, locale);
487 	if (r == NULL)
488 		return (-1);
489 	DEBUG(fprintf(stderr, "last modified: [%04d-%02d-%02d "
490 		  "%02d:%02d:%02d]\n",
491 		  tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
492 		  tm.tm_hour, tm.tm_min, tm.tm_sec));
493 	*mtime = timegm(&tm);
494 	return (0);
495 }
496 
497 /*
498  * Parse a content-length header
499  */
500 static int
501 http_parse_length(const char *p, off_t *length)
502 {
503 	off_t len;
504 
505 	for (len = 0; *p && isdigit((unsigned char)*p); ++p)
506 		len = len * 10 + (*p - '0');
507 	if (*p)
508 		return (-1);
509 	DEBUG(fprintf(stderr, "content length: [%lld]\n",
510 	    (long long)len));
511 	*length = len;
512 	return (0);
513 }
514 
515 /*
516  * Parse a content-range header
517  */
518 static int
519 http_parse_range(const char *p, off_t *offset, off_t *length, off_t *size)
520 {
521 	off_t first, last, len;
522 
523 	if (strncasecmp(p, "bytes ", 6) != 0)
524 		return (-1);
525 	p += 6;
526 	if (*p == '*') {
527 		first = last = -1;
528 		++p;
529 	} else {
530 		for (first = 0; *p && isdigit((unsigned char)*p); ++p)
531 			first = first * 10 + *p - '0';
532 		if (*p != '-')
533 			return (-1);
534 		for (last = 0, ++p; *p && isdigit((unsigned char)*p); ++p)
535 			last = last * 10 + *p - '0';
536 	}
537 	if (first > last || *p != '/')
538 		return (-1);
539 	for (len = 0, ++p; *p && isdigit((unsigned char)*p); ++p)
540 		len = len * 10 + *p - '0';
541 	if (*p || len < last - first + 1)
542 		return (-1);
543 	if (first == -1) {
544 		DEBUG(fprintf(stderr, "content range: [*/%lld]\n",
545 		    (long long)len));
546 		*length = 0;
547 	} else {
548 		DEBUG(fprintf(stderr, "content range: [%lld-%lld/%lld]\n",
549 		    (long long)first, (long long)last, (long long)len));
550 		*length = last - first + 1;
551 	}
552 	*offset = first;
553 	*size = len;
554 	return (0);
555 }
556 
557 
558 /*****************************************************************************
559  * Helper functions for authorization
560  */
561 
562 /*
563  * Base64 encoding
564  */
565 static char *
566 http_base64(const char *src)
567 {
568 	static const char base64[] =
569 	    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
570 	    "abcdefghijklmnopqrstuvwxyz"
571 	    "0123456789+/";
572 	char *str, *dst;
573 	size_t l;
574 	int t, r;
575 
576 	l = strlen(src);
577 	if ((str = malloc(((l + 2) / 3) * 4 + 1)) == NULL)
578 		return (NULL);
579 	dst = str;
580 	r = 0;
581 
582 	while (l >= 3) {
583 		t = (src[0] << 16) | (src[1] << 8) | src[2];
584 		dst[0] = base64[(t >> 18) & 0x3f];
585 		dst[1] = base64[(t >> 12) & 0x3f];
586 		dst[2] = base64[(t >> 6) & 0x3f];
587 		dst[3] = base64[(t >> 0) & 0x3f];
588 		src += 3; l -= 3;
589 		dst += 4; r += 4;
590 	}
591 
592 	switch (l) {
593 	case 2:
594 		t = (src[0] << 16) | (src[1] << 8);
595 		dst[0] = base64[(t >> 18) & 0x3f];
596 		dst[1] = base64[(t >> 12) & 0x3f];
597 		dst[2] = base64[(t >> 6) & 0x3f];
598 		dst[3] = '=';
599 		dst += 4;
600 		r += 4;
601 		break;
602 	case 1:
603 		t = src[0] << 16;
604 		dst[0] = base64[(t >> 18) & 0x3f];
605 		dst[1] = base64[(t >> 12) & 0x3f];
606 		dst[2] = dst[3] = '=';
607 		dst += 4;
608 		r += 4;
609 		break;
610 	case 0:
611 		break;
612 	}
613 
614 	*dst = 0;
615 	return (str);
616 }
617 
618 /*
619  * Encode username and password
620  */
621 static int
622 http_basic_auth(conn_t *conn, const char *hdr, const char *usr, const char *pwd)
623 {
624 	char *upw, *auth;
625 	int r;
626 
627 	DEBUG(fprintf(stderr, "usr: [%s]\n", usr));
628 	DEBUG(fprintf(stderr, "pwd: [%s]\n", pwd));
629 	if (asprintf(&upw, "%s:%s", usr, pwd) == -1)
630 		return (-1);
631 	auth = http_base64(upw);
632 	free(upw);
633 	if (auth == NULL)
634 		return (-1);
635 	r = http_cmd(conn, "%s: Basic %s", hdr, auth);
636 	free(auth);
637 	return (r);
638 }
639 
640 /*
641  * Send an authorization header
642  */
643 static int
644 http_authorize(conn_t *conn, const char *hdr, const char *p)
645 {
646 	/* basic authorization */
647 	if (strncasecmp(p, "basic:", 6) == 0) {
648 		char *user, *pwd, *str;
649 		int r;
650 
651 		/* skip realm */
652 		for (p += 6; *p && *p != ':'; ++p)
653 			/* nothing */ ;
654 		if (!*p || strchr(++p, ':') == NULL)
655 			return (-1);
656 		if ((str = strdup(p)) == NULL)
657 			return (-1); /* XXX */
658 		user = str;
659 		pwd = strchr(str, ':');
660 		*pwd++ = '\0';
661 		r = http_basic_auth(conn, hdr, user, pwd);
662 		free(str);
663 		return (r);
664 	}
665 	return (-1);
666 }
667 
668 
669 /*****************************************************************************
670  * Helper functions for connecting to a server or proxy
671  */
672 
673 /*
674  * Connect to the correct HTTP server or proxy.
675  */
676 static conn_t *
677 http_connect(struct url *URL, struct url *purl, const char *flags)
678 {
679 	conn_t *conn;
680 	int verbose;
681 	int af, val;
682 
683 #ifdef INET6
684 	af = AF_UNSPEC;
685 #else
686 	af = AF_INET;
687 #endif
688 
689 	verbose = CHECK_FLAG('v');
690 	if (CHECK_FLAG('4'))
691 		af = AF_INET;
692 #ifdef INET6
693 	else if (CHECK_FLAG('6'))
694 		af = AF_INET6;
695 #endif
696 
697 	if (purl && strcasecmp(URL->scheme, SCHEME_HTTPS) != 0) {
698 		URL = purl;
699 	} else if (strcasecmp(URL->scheme, SCHEME_FTP) == 0) {
700 		/* can't talk http to an ftp server */
701 		/* XXX should set an error code */
702 		return (NULL);
703 	}
704 
705 	if ((conn = fetch_connect(URL->host, URL->port, af, verbose)) == NULL)
706 		/* fetch_connect() has already set an error code */
707 		return (NULL);
708 	if (strcasecmp(URL->scheme, SCHEME_HTTPS) == 0 &&
709 	    fetch_ssl(conn, verbose) == -1) {
710 		fetch_close(conn);
711 		/* grrr */
712 		errno = EAUTH;
713 		fetch_syserr();
714 		return (NULL);
715 	}
716 
717 	val = 1;
718 	setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val, sizeof(val));
719 
720 	return (conn);
721 }
722 
723 static struct url *
724 http_get_proxy(struct url * url, const char *flags)
725 {
726 	struct url *purl;
727 	char *p;
728 
729 	if (flags != NULL && strchr(flags, 'd') != NULL)
730 		return (NULL);
731 	if (fetch_no_proxy_match(url->host))
732 		return (NULL);
733 	if (((p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
734 	    *p && (purl = fetchParseURL(p))) {
735 		if (!*purl->scheme)
736 			strcpy(purl->scheme, SCHEME_HTTP);
737 		if (!purl->port)
738 			purl->port = fetch_default_proxy_port(purl->scheme);
739 		if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
740 			return (purl);
741 		fetchFreeURL(purl);
742 	}
743 	return (NULL);
744 }
745 
746 static void
747 http_print_html(FILE *out, FILE *in)
748 {
749 	size_t len;
750 	char *line, *p, *q;
751 	int comment, tag;
752 
753 	comment = tag = 0;
754 	while ((line = fgetln(in, &len)) != NULL) {
755 		while (len && isspace((unsigned char)line[len - 1]))
756 			--len;
757 		for (p = q = line; q < line + len; ++q) {
758 			if (comment && *q == '-') {
759 				if (q + 2 < line + len &&
760 				    strcmp(q, "-->") == 0) {
761 					tag = comment = 0;
762 					q += 2;
763 				}
764 			} else if (tag && !comment && *q == '>') {
765 				p = q + 1;
766 				tag = 0;
767 			} else if (!tag && *q == '<') {
768 				if (q > p)
769 					fwrite(p, q - p, 1, out);
770 				tag = 1;
771 				if (q + 3 < line + len &&
772 				    strcmp(q, "<!--") == 0) {
773 					comment = 1;
774 					q += 3;
775 				}
776 			}
777 		}
778 		if (!tag && q > p)
779 			fwrite(p, q - p, 1, out);
780 		fputc('\n', out);
781 	}
782 }
783 
784 
785 /*****************************************************************************
786  * Core
787  */
788 
789 /*
790  * Send a request and process the reply
791  *
792  * XXX This function is way too long, the do..while loop should be split
793  * XXX off into a separate function.
794  */
795 FILE *
796 http_request(struct url *URL, const char *op, struct url_stat *us,
797     struct url *purl, const char *flags)
798 {
799 	conn_t *conn;
800 	struct url *url, *new;
801 	int chunked, direct, need_auth, noredirect, verbose;
802 	int e, i, n, val;
803 	off_t offset, clength, length, size;
804 	time_t mtime;
805 	const char *p;
806 	FILE *f;
807 	hdr_t h;
808 	char hbuf[MAXHOSTNAMELEN + 7], *host;
809 
810 	direct = CHECK_FLAG('d');
811 	noredirect = CHECK_FLAG('A');
812 	verbose = CHECK_FLAG('v');
813 
814 	if (direct && purl) {
815 		fetchFreeURL(purl);
816 		purl = NULL;
817 	}
818 
819 	/* try the provided URL first */
820 	url = URL;
821 
822 	/* if the A flag is set, we only get one try */
823 	n = noredirect ? 1 : MAX_REDIRECT;
824 	i = 0;
825 
826 	e = HTTP_PROTOCOL_ERROR;
827 	need_auth = 0;
828 	do {
829 		new = NULL;
830 		chunked = 0;
831 		offset = 0;
832 		clength = -1;
833 		length = -1;
834 		size = -1;
835 		mtime = 0;
836 
837 		/* check port */
838 		if (!url->port)
839 			url->port = fetch_default_port(url->scheme);
840 
841 		/* were we redirected to an FTP URL? */
842 		if (purl == NULL && strcmp(url->scheme, SCHEME_FTP) == 0) {
843 			if (strcmp(op, "GET") == 0)
844 				return (ftp_request(url, "RETR", us, purl, flags));
845 			else if (strcmp(op, "HEAD") == 0)
846 				return (ftp_request(url, "STAT", us, purl, flags));
847 		}
848 
849 		/* connect to server or proxy */
850 		if ((conn = http_connect(url, purl, flags)) == NULL)
851 			goto ouch;
852 
853 		host = url->host;
854 #ifdef INET6
855 		if (strchr(url->host, ':')) {
856 			snprintf(hbuf, sizeof(hbuf), "[%s]", url->host);
857 			host = hbuf;
858 		}
859 #endif
860 		if (url->port != fetch_default_port(url->scheme)) {
861 			if (host != hbuf) {
862 				strcpy(hbuf, host);
863 				host = hbuf;
864 			}
865 			snprintf(hbuf + strlen(hbuf),
866 			    sizeof(hbuf) - strlen(hbuf), ":%d", url->port);
867 		}
868 
869 		/* send request */
870 		if (verbose)
871 			fetch_info("requesting %s://%s%s",
872 			    url->scheme, host, url->doc);
873 		if (purl) {
874 			http_cmd(conn, "%s %s://%s%s HTTP/1.1",
875 			    op, url->scheme, host, url->doc);
876 		} else {
877 			http_cmd(conn, "%s %s HTTP/1.1",
878 			    op, url->doc);
879 		}
880 
881 		/* virtual host */
882 		http_cmd(conn, "Host: %s", host);
883 
884 		/* proxy authorization */
885 		if (purl) {
886 			if (*purl->user || *purl->pwd)
887 				http_basic_auth(conn, "Proxy-Authorization",
888 				    purl->user, purl->pwd);
889 			else if ((p = getenv("HTTP_PROXY_AUTH")) != NULL && *p != '\0')
890 				http_authorize(conn, "Proxy-Authorization", p);
891 		}
892 
893 		/* server authorization */
894 		if (need_auth || *url->user || *url->pwd) {
895 			if (*url->user || *url->pwd)
896 				http_basic_auth(conn, "Authorization", url->user, url->pwd);
897 			else if ((p = getenv("HTTP_AUTH")) != NULL && *p != '\0')
898 				http_authorize(conn, "Authorization", p);
899 			else if (fetchAuthMethod && fetchAuthMethod(url) == 0) {
900 				http_basic_auth(conn, "Authorization", url->user, url->pwd);
901 			} else {
902 				http_seterr(HTTP_NEED_AUTH);
903 				goto ouch;
904 			}
905 		}
906 
907 		/* other headers */
908 		if ((p = getenv("HTTP_REFERER")) != NULL && *p != '\0') {
909 			if (strcasecmp(p, "auto") == 0)
910 				http_cmd(conn, "Referer: %s://%s%s",
911 				    url->scheme, host, url->doc);
912 			else
913 				http_cmd(conn, "Referer: %s", p);
914 		}
915 		if ((p = getenv("HTTP_USER_AGENT")) != NULL && *p != '\0')
916 			http_cmd(conn, "User-Agent: %s", p);
917 		else
918 			http_cmd(conn, "User-Agent: %s " _LIBFETCH_VER, getprogname());
919 		if (url->offset > 0)
920 			http_cmd(conn, "Range: bytes=%lld-", (long long)url->offset);
921 		http_cmd(conn, "Connection: close");
922 		http_cmd(conn, "");
923 
924 		/*
925 		 * Force the queued request to be dispatched.  Normally, one
926 		 * would do this with shutdown(2) but squid proxies can be
927 		 * configured to disallow such half-closed connections.  To
928 		 * be compatible with such configurations, fiddle with socket
929 		 * options to force the pending data to be written.
930 		 */
931 		val = 0;
932 		setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val,
933 			   sizeof(val));
934 		val = 1;
935 		setsockopt(conn->sd, IPPROTO_TCP, TCP_NODELAY, &val,
936 			   sizeof(val));
937 
938 		/* get reply */
939 		switch (http_get_reply(conn)) {
940 		case HTTP_OK:
941 		case HTTP_PARTIAL:
942 			/* fine */
943 			break;
944 		case HTTP_MOVED_PERM:
945 		case HTTP_MOVED_TEMP:
946 		case HTTP_SEE_OTHER:
947 			/*
948 			 * Not so fine, but we still have to read the
949 			 * headers to get the new location.
950 			 */
951 			break;
952 		case HTTP_NEED_AUTH:
953 			if (need_auth) {
954 				/*
955 				 * We already sent out authorization code,
956 				 * so there's nothing more we can do.
957 				 */
958 				http_seterr(conn->err);
959 				goto ouch;
960 			}
961 			/* try again, but send the password this time */
962 			if (verbose)
963 				fetch_info("server requires authorization");
964 			break;
965 		case HTTP_NEED_PROXY_AUTH:
966 			/*
967 			 * If we're talking to a proxy, we already sent
968 			 * our proxy authorization code, so there's
969 			 * nothing more we can do.
970 			 */
971 			http_seterr(conn->err);
972 			goto ouch;
973 		case HTTP_BAD_RANGE:
974 			/*
975 			 * This can happen if we ask for 0 bytes because
976 			 * we already have the whole file.  Consider this
977 			 * a success for now, and check sizes later.
978 			 */
979 			break;
980 		case HTTP_PROTOCOL_ERROR:
981 			/* fall through */
982 		case -1:
983 			fetch_syserr();
984 			goto ouch;
985 		default:
986 			http_seterr(conn->err);
987 			if (!verbose)
988 				goto ouch;
989 			/* fall through so we can get the full error message */
990 		}
991 
992 		/* get headers */
993 		do {
994 			switch ((h = http_next_header(conn, &p))) {
995 			case hdr_syserror:
996 				fetch_syserr();
997 				goto ouch;
998 			case hdr_error:
999 				http_seterr(HTTP_PROTOCOL_ERROR);
1000 				goto ouch;
1001 			case hdr_content_length:
1002 				http_parse_length(p, &clength);
1003 				break;
1004 			case hdr_content_range:
1005 				http_parse_range(p, &offset, &length, &size);
1006 				break;
1007 			case hdr_last_modified:
1008 				http_parse_mtime(p, &mtime);
1009 				break;
1010 			case hdr_location:
1011 				if (!HTTP_REDIRECT(conn->err))
1012 					break;
1013 				if (new)
1014 					free(new);
1015 				if (verbose)
1016 					fetch_info("%d redirect to %s", conn->err, p);
1017 				if (*p == '/')
1018 					/* absolute path */
1019 					new = fetchMakeURL(url->scheme, url->host, url->port, p,
1020 					    url->user, url->pwd);
1021 				else
1022 					new = fetchParseURL(p);
1023 				if (new == NULL) {
1024 					/* XXX should set an error code */
1025 					DEBUG(fprintf(stderr, "failed to parse new URL\n"));
1026 					goto ouch;
1027 				}
1028 				if (!*new->user && !*new->pwd) {
1029 					strcpy(new->user, url->user);
1030 					strcpy(new->pwd, url->pwd);
1031 				}
1032 				new->offset = url->offset;
1033 				new->length = url->length;
1034 				break;
1035 			case hdr_transfer_encoding:
1036 				/* XXX weak test*/
1037 				chunked = (strcasecmp(p, "chunked") == 0);
1038 				break;
1039 			case hdr_www_authenticate:
1040 				if (conn->err != HTTP_NEED_AUTH)
1041 					break;
1042 				/* if we were smarter, we'd check the method and realm */
1043 				break;
1044 			case hdr_end:
1045 				/* fall through */
1046 			case hdr_unknown:
1047 				/* ignore */
1048 				break;
1049 			}
1050 		} while (h > hdr_end);
1051 
1052 		/* we need to provide authentication */
1053 		if (conn->err == HTTP_NEED_AUTH) {
1054 			e = conn->err;
1055 			need_auth = 1;
1056 			fetch_close(conn);
1057 			conn = NULL;
1058 			continue;
1059 		}
1060 
1061 		/* requested range not satisfiable */
1062 		if (conn->err == HTTP_BAD_RANGE) {
1063 			if (url->offset == size && url->length == 0) {
1064 				/* asked for 0 bytes; fake it */
1065 				offset = url->offset;
1066 				conn->err = HTTP_OK;
1067 				break;
1068 			} else {
1069 				http_seterr(conn->err);
1070 				goto ouch;
1071 			}
1072 		}
1073 
1074 		/* we have a hit or an error */
1075 		if (conn->err == HTTP_OK || conn->err == HTTP_PARTIAL || HTTP_ERROR(conn->err))
1076 			break;
1077 
1078 		/* all other cases: we got a redirect */
1079 		e = conn->err;
1080 		need_auth = 0;
1081 		fetch_close(conn);
1082 		conn = NULL;
1083 		if (!new) {
1084 			DEBUG(fprintf(stderr, "redirect with no new location\n"));
1085 			break;
1086 		}
1087 		if (url != URL)
1088 			fetchFreeURL(url);
1089 		url = new;
1090 	} while (++i < n);
1091 
1092 	/* we failed, or ran out of retries */
1093 	if (conn == NULL) {
1094 		http_seterr(e);
1095 		goto ouch;
1096 	}
1097 
1098 	DEBUG(fprintf(stderr, "offset %lld, length %lld,"
1099 		  " size %lld, clength %lld\n",
1100 		  (long long)offset, (long long)length,
1101 		  (long long)size, (long long)clength));
1102 
1103 	/* check for inconsistencies */
1104 	if (clength != -1 && length != -1 && clength != length) {
1105 		http_seterr(HTTP_PROTOCOL_ERROR);
1106 		goto ouch;
1107 	}
1108 	if (clength == -1)
1109 		clength = length;
1110 	if (clength != -1)
1111 		length = offset + clength;
1112 	if (length != -1 && size != -1 && length != size) {
1113 		http_seterr(HTTP_PROTOCOL_ERROR);
1114 		goto ouch;
1115 	}
1116 	if (size == -1)
1117 		size = length;
1118 
1119 	/* fill in stats */
1120 	if (us) {
1121 		us->size = size;
1122 		us->atime = us->mtime = mtime;
1123 	}
1124 
1125 	/* too far? */
1126 	if (URL->offset > 0 && offset > URL->offset) {
1127 		http_seterr(HTTP_PROTOCOL_ERROR);
1128 		goto ouch;
1129 	}
1130 
1131 	/* report back real offset and size */
1132 	URL->offset = offset;
1133 	URL->length = clength;
1134 
1135 	/* wrap it up in a FILE */
1136 	if ((f = http_funopen(conn, chunked)) == NULL) {
1137 		fetch_syserr();
1138 		goto ouch;
1139 	}
1140 
1141 	if (url != URL)
1142 		fetchFreeURL(url);
1143 	if (purl)
1144 		fetchFreeURL(purl);
1145 
1146 	if (HTTP_ERROR(conn->err)) {
1147 		http_print_html(stderr, f);
1148 		fclose(f);
1149 		f = NULL;
1150 	}
1151 
1152 	return (f);
1153 
1154 ouch:
1155 	if (url != URL)
1156 		fetchFreeURL(url);
1157 	if (purl)
1158 		fetchFreeURL(purl);
1159 	if (conn != NULL)
1160 		fetch_close(conn);
1161 	return (NULL);
1162 }
1163 
1164 
1165 /*****************************************************************************
1166  * Entry points
1167  */
1168 
1169 /*
1170  * Retrieve and stat a file by HTTP
1171  */
1172 FILE *
1173 fetchXGetHTTP(struct url *URL, struct url_stat *us, const char *flags)
1174 {
1175 	return (http_request(URL, "GET", us, http_get_proxy(URL, flags), flags));
1176 }
1177 
1178 /*
1179  * Retrieve a file by HTTP
1180  */
1181 FILE *
1182 fetchGetHTTP(struct url *URL, const char *flags)
1183 {
1184 	return (fetchXGetHTTP(URL, NULL, flags));
1185 }
1186 
1187 /*
1188  * Store a file by HTTP
1189  */
1190 FILE *
1191 fetchPutHTTP(struct url *URL __unused, const char *flags __unused)
1192 {
1193 	warnx("fetchPutHTTP(): not implemented");
1194 	return (NULL);
1195 }
1196 
1197 /*
1198  * Get an HTTP document's metadata
1199  */
1200 int
1201 fetchStatHTTP(struct url *URL, struct url_stat *us, const char *flags)
1202 {
1203 	FILE *f;
1204 
1205 	f = http_request(URL, "HEAD", us, http_get_proxy(URL, flags), flags);
1206 	if (f == NULL)
1207 		return (-1);
1208 	fclose(f);
1209 	return (0);
1210 }
1211 
1212 /*
1213  * List a directory
1214  */
1215 struct url_ent *
1216 fetchListHTTP(struct url *url __unused, const char *flags __unused)
1217 {
1218 	warnx("fetchListHTTP(): not implemented");
1219 	return (NULL);
1220 }
1221