xref: /dflybsd-src/lib/libfetch/http.c (revision 3eca42272f995aeaee9d72266e8812fa6860c9da)
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  * $FreeBSD: src/lib/libfetch/http.c,v 1.86 2008/12/15 08:27:44 murray Exp $
29  * $DragonFly: src/lib/libfetch/http.c,v 1.4 2007/08/05 21:48:12 swildner Exp $
30  */
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 #include <sys/time.h>
67 
68 #include <ctype.h>
69 #include <err.h>
70 #include <errno.h>
71 #include <locale.h>
72 #include <netdb.h>
73 #include <stdarg.h>
74 #include <stdio.h>
75 #include <stdlib.h>
76 #include <string.h>
77 #include <time.h>
78 #include <unistd.h>
79 
80 #include <netinet/in.h>
81 #include <netinet/tcp.h>
82 
83 #include "fetch.h"
84 #include "common.h"
85 #include "httperr.h"
86 
87 /* Maximum number of redirects to follow */
88 #define MAX_REDIRECT 20
89 
90 /* Symbolic names for reply codes we care about */
91 #define HTTP_OK			200
92 #define HTTP_PARTIAL		206
93 #define HTTP_MOVED_PERM		301
94 #define HTTP_MOVED_TEMP		302
95 #define HTTP_SEE_OTHER		303
96 #define HTTP_NOT_MODIFIED	304
97 #define HTTP_TEMP_REDIRECT	307
98 #define HTTP_NEED_AUTH		401
99 #define HTTP_NEED_PROXY_AUTH	407
100 #define HTTP_BAD_RANGE		416
101 #define HTTP_PROTOCOL_ERROR	999
102 
103 #define HTTP_REDIRECT(xyz) ((xyz) == HTTP_MOVED_PERM \
104 			    || (xyz) == HTTP_MOVED_TEMP \
105 			    || (xyz) == HTTP_TEMP_REDIRECT \
106 			    || (xyz) == HTTP_SEE_OTHER)
107 
108 #define HTTP_ERROR(xyz) ((xyz) > 400 && (xyz) < 599)
109 
110 
111 /*****************************************************************************
112  * I/O functions for decoding chunked streams
113  */
114 
115 struct httpio
116 {
117 	conn_t		*conn;		/* connection */
118 	int		 chunked;	/* chunked mode */
119 	char		*buf;		/* chunk buffer */
120 	size_t		 bufsize;	/* size of chunk buffer */
121 	ssize_t		 buflen;	/* amount of data currently in buffer */
122 	int		 bufpos;	/* current read offset in buffer */
123 	int		 eof;		/* end-of-file flag */
124 	int		 error;		/* error flag */
125 	size_t		 chunksize;	/* remaining size of current chunk */
126 #ifndef NDEBUG
127 	size_t		 total;
128 #endif
129 };
130 
131 static int http_cmd(conn_t *, const char *, ...) __printflike(2, 3);
132 
133 /*
134  * Get next chunk header
135  */
136 static int
137 http_new_chunk(struct httpio *io)
138 {
139 	char *p;
140 
141 	if (fetch_getln(io->conn) == -1)
142 		return (-1);
143 
144 	if (io->conn->buflen < 2 || !isxdigit((unsigned char)*io->conn->buf))
145 		return (-1);
146 
147 	for (p = io->conn->buf; *p && !isspace((unsigned char)*p); ++p) {
148 		if (*p == ';')
149 			break;
150 		if (!isxdigit((unsigned char)*p))
151 			return (-1);
152 		if (isdigit((unsigned char)*p)) {
153 			io->chunksize = io->chunksize * 16 +
154 			    *p - '0';
155 		} else {
156 			io->chunksize = io->chunksize * 16 +
157 			    10 + tolower((unsigned char)*p) - 'a';
158 		}
159 	}
160 
161 #ifndef NDEBUG
162 	if (fetchDebug) {
163 		io->total += io->chunksize;
164 		if (io->chunksize == 0)
165 			fprintf(stderr, "%s(): end of last chunk\n", __func__);
166 		else
167 			fprintf(stderr, "%s(): new chunk: %lu (%lu)\n",
168 			    __func__, (unsigned long)io->chunksize,
169 			    (unsigned long)io->total);
170 	}
171 #endif
172 
173 	return (io->chunksize);
174 }
175 
176 /*
177  * Grow the input buffer to at least len bytes
178  */
179 static inline int
180 http_growbuf(struct httpio *io, size_t len)
181 {
182 	char *tmp;
183 
184 	if (io->bufsize >= len)
185 		return (0);
186 
187 	if ((tmp = realloc(io->buf, len)) == NULL)
188 		return (-1);
189 	io->buf = tmp;
190 	io->bufsize = len;
191 	return (0);
192 }
193 
194 /*
195  * Fill the input buffer, do chunk decoding on the fly
196  */
197 static int
198 http_fillbuf(struct httpio *io, size_t len)
199 {
200 	ssize_t nbytes;
201 
202 	if (io->error)
203 		return (-1);
204 	if (io->eof)
205 		return (0);
206 
207 	if (io->chunked == 0) {
208 		if (http_growbuf(io, len) == -1)
209 			return (-1);
210 		if ((nbytes = fetch_read(io->conn, io->buf, len)) == -1) {
211 			io->error = errno;
212 			return (-1);
213 		}
214 		io->buflen = nbytes;
215 		io->bufpos = 0;
216 		return (io->buflen);
217 	}
218 
219 	if (io->chunksize == 0) {
220 		switch (http_new_chunk(io)) {
221 		case -1:
222 			io->error = 1;
223 			return (-1);
224 		case 0:
225 			io->eof = 1;
226 			return (0);
227 		}
228 	}
229 
230 	if (len > io->chunksize)
231 		len = io->chunksize;
232 	if (http_growbuf(io, len) == -1)
233 		return (-1);
234 	if ((nbytes = fetch_read(io->conn, io->buf, len)) == -1) {
235 		io->error = errno;
236 		return (-1);
237 	}
238 	io->buflen = nbytes;
239 	io->chunksize -= io->buflen;
240 
241 	if (io->chunksize == 0) {
242 		char endl[2];
243 
244 		if (fetch_read(io->conn, endl, 2) != 2 ||
245 		    endl[0] != '\r' || endl[1] != '\n')
246 			return (-1);
247 	}
248 
249 	io->bufpos = 0;
250 
251 	return (io->buflen);
252 }
253 
254 /*
255  * Read function
256  */
257 static int
258 http_readfn(void *v, char *buf, int len)
259 {
260 	struct httpio *io = (struct httpio *)v;
261 	int l, pos;
262 
263 	if (io->error)
264 		return (-1);
265 	if (io->eof)
266 		return (0);
267 
268 	for (pos = 0; len > 0; pos += l, len -= l) {
269 		/* empty buffer */
270 		if (!io->buf || io->bufpos == io->buflen)
271 			if (http_fillbuf(io, len) < 1)
272 				break;
273 		l = io->buflen - io->bufpos;
274 		if (len < l)
275 			l = len;
276 		memcpy(buf + pos, io->buf + io->bufpos, l);
277 		io->bufpos += l;
278 	}
279 
280 	if (!pos && io->error) {
281 		if (io->error == EINTR)
282 			io->error = 0;
283 		return (-1);
284 	}
285 	return (pos);
286 }
287 
288 /*
289  * Write function
290  */
291 static int
292 http_writefn(void *v, const char *buf, int len)
293 {
294 	struct httpio *io = (struct httpio *)v;
295 
296 	return (fetch_write(io->conn, buf, len));
297 }
298 
299 /*
300  * Close function
301  */
302 static int
303 http_closefn(void *v)
304 {
305 	struct httpio *io = (struct httpio *)v;
306 	int r;
307 
308 	r = fetch_close(io->conn);
309 	if (io->buf)
310 		free(io->buf);
311 	free(io);
312 	return (r);
313 }
314 
315 /*
316  * Wrap a file descriptor up
317  */
318 static FILE *
319 http_funopen(conn_t *conn, int chunked)
320 {
321 	struct httpio *io;
322 	FILE *f;
323 
324 	if ((io = calloc(1, sizeof(*io))) == NULL) {
325 		fetch_syserr();
326 		return (NULL);
327 	}
328 	io->conn = conn;
329 	io->chunked = chunked;
330 	f = funopen(io, http_readfn, http_writefn, NULL, http_closefn);
331 	if (f == NULL) {
332 		fetch_syserr();
333 		free(io);
334 		return (NULL);
335 	}
336 	return (f);
337 }
338 
339 
340 /*****************************************************************************
341  * Helper functions for talking to the server and parsing its replies
342  */
343 
344 /* Header types */
345 typedef enum {
346 	hdr_syserror = -2,
347 	hdr_error = -1,
348 	hdr_end = 0,
349 	hdr_unknown = 1,
350 	hdr_content_length,
351 	hdr_content_range,
352 	hdr_last_modified,
353 	hdr_location,
354 	hdr_transfer_encoding,
355 	hdr_www_authenticate
356 } hdr_t;
357 
358 /* Names of interesting headers */
359 static struct {
360 	hdr_t		 num;
361 	const char	*name;
362 } hdr_names[] = {
363 	{ hdr_content_length,		"Content-Length" },
364 	{ hdr_content_range,		"Content-Range" },
365 	{ hdr_last_modified,		"Last-Modified" },
366 	{ hdr_location,			"Location" },
367 	{ hdr_transfer_encoding,	"Transfer-Encoding" },
368 	{ hdr_www_authenticate,		"WWW-Authenticate" },
369 	{ hdr_unknown,			NULL },
370 };
371 
372 /*
373  * Send a formatted line; optionally echo to terminal
374  */
375 static int
376 http_cmd(conn_t *conn, const char *fmt, ...)
377 {
378 	va_list ap;
379 	size_t len;
380 	char *msg;
381 	int r;
382 
383 	va_start(ap, fmt);
384 	len = vasprintf(&msg, fmt, ap);
385 	va_end(ap);
386 
387 	if (msg == NULL) {
388 		errno = ENOMEM;
389 		fetch_syserr();
390 		return (-1);
391 	}
392 
393 	r = fetch_putln(conn, msg, len);
394 	free(msg);
395 
396 	if (r == -1) {
397 		fetch_syserr();
398 		return (-1);
399 	}
400 
401 	return (0);
402 }
403 
404 /*
405  * Get and parse status line
406  */
407 static int
408 http_get_reply(conn_t *conn)
409 {
410 	char *p;
411 
412 	if (fetch_getln(conn) == -1)
413 		return (-1);
414 	/*
415 	 * A valid status line looks like "HTTP/m.n xyz reason" where m
416 	 * and n are the major and minor protocol version numbers and xyz
417 	 * is the reply code.
418 	 * Unfortunately, there are servers out there (NCSA 1.5.1, to name
419 	 * just one) that do not send a version number, so we can't rely
420 	 * on finding one, but if we do, insist on it being 1.0 or 1.1.
421 	 * We don't care about the reason phrase.
422 	 */
423 	if (strncmp(conn->buf, "HTTP", 4) != 0)
424 		return (HTTP_PROTOCOL_ERROR);
425 	p = conn->buf + 4;
426 	if (*p == '/') {
427 		if (p[1] != '1' || p[2] != '.' || (p[3] != '0' && p[3] != '1'))
428 			return (HTTP_PROTOCOL_ERROR);
429 		p += 4;
430 	}
431 	if (*p != ' ' ||
432 	    !isdigit((unsigned char)p[1]) ||
433 	    !isdigit((unsigned char)p[2]) ||
434 	    !isdigit((unsigned char)p[3]))
435 		return (HTTP_PROTOCOL_ERROR);
436 
437 	conn->err = (p[1] - '0') * 100 + (p[2] - '0') * 10 + (p[3] - '0');
438 	return (conn->err);
439 }
440 
441 /*
442  * Check a header; if the type matches the given string, return a pointer
443  * to the beginning of the value.
444  */
445 static const char *
446 http_match(const char *str, const char *hdr)
447 {
448 	while (*str && *hdr &&
449 	    tolower((unsigned char)*str++) == tolower((unsigned char)*hdr++))
450 		/* nothing */;
451 	if (*str || *hdr != ':')
452 		return (NULL);
453 	while (*hdr && isspace((unsigned char)*++hdr))
454 		/* nothing */;
455 	return (hdr);
456 }
457 
458 /*
459  * Get the next header and return the appropriate symbolic code.
460  */
461 static hdr_t
462 http_next_header(conn_t *conn, const char **p)
463 {
464 	int i;
465 
466 	if (fetch_getln(conn) == -1)
467 		return (hdr_syserror);
468 	while (conn->buflen && isspace((unsigned char)conn->buf[conn->buflen - 1]))
469 		conn->buflen--;
470 	conn->buf[conn->buflen] = '\0';
471 	if (conn->buflen == 0)
472 		return (hdr_end);
473 	/*
474 	 * We could check for malformed headers but we don't really care.
475 	 * A valid header starts with a token immediately followed by a
476 	 * colon; a token is any sequence of non-control, non-whitespace
477 	 * characters except "()<>@,;:\\\"{}".
478 	 */
479 	for (i = 0; hdr_names[i].num != hdr_unknown; i++)
480 		if ((*p = http_match(hdr_names[i].name, conn->buf)) != NULL)
481 			return (hdr_names[i].num);
482 	return (hdr_unknown);
483 }
484 
485 /*
486  * Parse a last-modified header
487  */
488 static int
489 http_parse_mtime(const char *p, time_t *mtime)
490 {
491 	char locale[64], *r;
492 	struct tm tm;
493 
494 	strncpy(locale, setlocale(LC_TIME, NULL), sizeof(locale));
495 	setlocale(LC_TIME, "C");
496 	r = strptime(p, "%a, %d %b %Y %H:%M:%S GMT", &tm);
497 	/* XXX should add support for date-2 and date-3 */
498 	setlocale(LC_TIME, locale);
499 	if (r == NULL)
500 		return (-1);
501 	DEBUG(fprintf(stderr, "last modified: [%04d-%02d-%02d "
502 		  "%02d:%02d:%02d]\n",
503 		  tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
504 		  tm.tm_hour, tm.tm_min, tm.tm_sec));
505 	*mtime = timegm(&tm);
506 	return (0);
507 }
508 
509 /*
510  * Parse a content-length header
511  */
512 static int
513 http_parse_length(const char *p, off_t *length)
514 {
515 	off_t len;
516 
517 	for (len = 0; *p && isdigit((unsigned char)*p); ++p)
518 		len = len * 10 + (*p - '0');
519 	if (*p)
520 		return (-1);
521 	DEBUG(fprintf(stderr, "content length: [%lld]\n",
522 	    (long long)len));
523 	*length = len;
524 	return (0);
525 }
526 
527 /*
528  * Parse a content-range header
529  */
530 static int
531 http_parse_range(const char *p, off_t *offset, off_t *length, off_t *size)
532 {
533 	off_t first, last, len;
534 
535 	if (strncasecmp(p, "bytes ", 6) != 0)
536 		return (-1);
537 	p += 6;
538 	if (*p == '*') {
539 		first = last = -1;
540 		++p;
541 	} else {
542 		for (first = 0; *p && isdigit((unsigned char)*p); ++p)
543 			first = first * 10 + *p - '0';
544 		if (*p != '-')
545 			return (-1);
546 		for (last = 0, ++p; *p && isdigit((unsigned char)*p); ++p)
547 			last = last * 10 + *p - '0';
548 	}
549 	if (first > last || *p != '/')
550 		return (-1);
551 	for (len = 0, ++p; *p && isdigit((unsigned char)*p); ++p)
552 		len = len * 10 + *p - '0';
553 	if (*p || len < last - first + 1)
554 		return (-1);
555 	if (first == -1) {
556 		DEBUG(fprintf(stderr, "content range: [*/%lld]\n",
557 		    (long long)len));
558 		*length = 0;
559 	} else {
560 		DEBUG(fprintf(stderr, "content range: [%lld-%lld/%lld]\n",
561 		    (long long)first, (long long)last, (long long)len));
562 		*length = last - first + 1;
563 	}
564 	*offset = first;
565 	*size = len;
566 	return (0);
567 }
568 
569 
570 /*****************************************************************************
571  * Helper functions for authorization
572  */
573 
574 /*
575  * Base64 encoding
576  */
577 static char *
578 http_base64(const char *src)
579 {
580 	static const char base64[] =
581 	    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
582 	    "abcdefghijklmnopqrstuvwxyz"
583 	    "0123456789+/";
584 	char *str, *dst;
585 	size_t l;
586 	int t, r;
587 
588 	l = strlen(src);
589 	if ((str = malloc(((l + 2) / 3) * 4 + 1)) == NULL)
590 		return (NULL);
591 	dst = str;
592 	r = 0;
593 
594 	while (l >= 3) {
595 		t = (src[0] << 16) | (src[1] << 8) | src[2];
596 		dst[0] = base64[(t >> 18) & 0x3f];
597 		dst[1] = base64[(t >> 12) & 0x3f];
598 		dst[2] = base64[(t >> 6) & 0x3f];
599 		dst[3] = base64[(t >> 0) & 0x3f];
600 		src += 3; l -= 3;
601 		dst += 4; r += 4;
602 	}
603 
604 	switch (l) {
605 	case 2:
606 		t = (src[0] << 16) | (src[1] << 8);
607 		dst[0] = base64[(t >> 18) & 0x3f];
608 		dst[1] = base64[(t >> 12) & 0x3f];
609 		dst[2] = base64[(t >> 6) & 0x3f];
610 		dst[3] = '=';
611 		dst += 4;
612 		r += 4;
613 		break;
614 	case 1:
615 		t = src[0] << 16;
616 		dst[0] = base64[(t >> 18) & 0x3f];
617 		dst[1] = base64[(t >> 12) & 0x3f];
618 		dst[2] = dst[3] = '=';
619 		dst += 4;
620 		r += 4;
621 		break;
622 	case 0:
623 		break;
624 	}
625 
626 	*dst = 0;
627 	return (str);
628 }
629 
630 /*
631  * Encode username and password
632  */
633 static int
634 http_basic_auth(conn_t *conn, const char *hdr, const char *usr, const char *pwd)
635 {
636 	char *upw, *auth;
637 	int r;
638 
639 	DEBUG(fprintf(stderr, "usr: [%s]\n", usr));
640 	DEBUG(fprintf(stderr, "pwd: [%s]\n", pwd));
641 	if (asprintf(&upw, "%s:%s", usr, pwd) == -1)
642 		return (-1);
643 	auth = http_base64(upw);
644 	free(upw);
645 	if (auth == NULL)
646 		return (-1);
647 	r = http_cmd(conn, "%s: Basic %s", hdr, auth);
648 	free(auth);
649 	return (r);
650 }
651 
652 /*
653  * Send an authorization header
654  */
655 static int
656 http_authorize(conn_t *conn, const char *hdr, const char *p)
657 {
658 	/* basic authorization */
659 	if (strncasecmp(p, "basic:", 6) == 0) {
660 		char *user, *pwd, *str;
661 		int r;
662 
663 		/* skip realm */
664 		for (p += 6; *p && *p != ':'; ++p)
665 			/* nothing */ ;
666 		if (!*p || strchr(++p, ':') == NULL)
667 			return (-1);
668 		if ((str = strdup(p)) == NULL)
669 			return (-1); /* XXX */
670 		user = str;
671 		pwd = strchr(str, ':');
672 		*pwd++ = '\0';
673 		r = http_basic_auth(conn, hdr, user, pwd);
674 		free(str);
675 		return (r);
676 	}
677 	return (-1);
678 }
679 
680 
681 /*****************************************************************************
682  * Helper functions for connecting to a server or proxy
683  */
684 
685 /*
686  * Connect to the correct HTTP server or proxy.
687  */
688 static conn_t *
689 http_connect(struct url *URL, struct url *purl, const char *flags)
690 {
691 	conn_t *conn;
692 	int verbose;
693 	int af, val;
694 
695 #ifdef INET6
696 	af = AF_UNSPEC;
697 #else
698 	af = AF_INET;
699 #endif
700 
701 	verbose = CHECK_FLAG('v');
702 	if (CHECK_FLAG('4'))
703 		af = AF_INET;
704 #ifdef INET6
705 	else if (CHECK_FLAG('6'))
706 		af = AF_INET6;
707 #endif
708 
709 	if (purl && strcasecmp(URL->scheme, SCHEME_HTTPS) != 0) {
710 		URL = purl;
711 	} else if (strcasecmp(URL->scheme, SCHEME_FTP) == 0) {
712 		/* can't talk http to an ftp server */
713 		/* XXX should set an error code */
714 		return (NULL);
715 	}
716 
717 	if ((conn = fetch_connect(URL->host, URL->port, af, verbose)) == NULL)
718 		/* fetch_connect() has already set an error code */
719 		return (NULL);
720 	if (strcasecmp(URL->scheme, SCHEME_HTTPS) == 0 &&
721 	    fetch_ssl(conn, verbose) == -1) {
722 		fetch_close(conn);
723 		/* grrr */
724 		errno = EAUTH;
725 		fetch_syserr();
726 		return (NULL);
727 	}
728 
729 	val = 1;
730 	setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val, sizeof(val));
731 
732 	return (conn);
733 }
734 
735 static struct url *
736 http_get_proxy(struct url * url, const char *flags)
737 {
738 	struct url *purl;
739 	char *p;
740 
741 	if (flags != NULL && strchr(flags, 'd') != NULL)
742 		return (NULL);
743 	if (fetch_no_proxy_match(url->host))
744 		return (NULL);
745 	if (((p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
746 	    *p && (purl = fetchParseURL(p))) {
747 		if (!*purl->scheme)
748 			strcpy(purl->scheme, SCHEME_HTTP);
749 		if (!purl->port)
750 			purl->port = fetch_default_proxy_port(purl->scheme);
751 		if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
752 			return (purl);
753 		fetchFreeURL(purl);
754 	}
755 	return (NULL);
756 }
757 
758 static void
759 http_print_html(FILE *out, FILE *in)
760 {
761 	size_t len;
762 	char *line, *p, *q;
763 	int comment, tag;
764 
765 	comment = tag = 0;
766 	while ((line = fgetln(in, &len)) != NULL) {
767 		while (len && isspace((unsigned char)line[len - 1]))
768 			--len;
769 		for (p = q = line; q < line + len; ++q) {
770 			if (comment && *q == '-') {
771 				if (q + 2 < line + len &&
772 				    strcmp(q, "-->") == 0) {
773 					tag = comment = 0;
774 					q += 2;
775 				}
776 			} else if (tag && !comment && *q == '>') {
777 				p = q + 1;
778 				tag = 0;
779 			} else if (!tag && *q == '<') {
780 				if (q > p)
781 					fwrite(p, q - p, 1, out);
782 				tag = 1;
783 				if (q + 3 < line + len &&
784 				    strcmp(q, "<!--") == 0) {
785 					comment = 1;
786 					q += 3;
787 				}
788 			}
789 		}
790 		if (!tag && q > p)
791 			fwrite(p, q - p, 1, out);
792 		fputc('\n', out);
793 	}
794 }
795 
796 
797 /*****************************************************************************
798  * Core
799  */
800 
801 /*
802  * Send a request and process the reply
803  *
804  * XXX This function is way too long, the do..while loop should be split
805  * XXX off into a separate function.
806  */
807 FILE *
808 http_request(struct url *URL, const char *op, struct url_stat *us,
809     struct url *purl, const char *flags)
810 {
811 	char timebuf[80];
812 	char hbuf[MAXHOSTNAMELEN + 7], *host;
813 	conn_t *conn;
814 	struct url *url, *new;
815 	int chunked, direct, ims, need_auth, noredirect, verbose;
816 	int e, i, n, val;
817 	off_t offset, clength, length, size;
818 	time_t mtime;
819 	const char *p;
820 	FILE *f;
821 	hdr_t h;
822 	struct tm *timestruct;
823 
824 	direct = CHECK_FLAG('d');
825 	noredirect = CHECK_FLAG('A');
826 	verbose = CHECK_FLAG('v');
827 	ims = CHECK_FLAG('i');
828 
829 	if (direct && purl) {
830 		fetchFreeURL(purl);
831 		purl = NULL;
832 	}
833 
834 	/* try the provided URL first */
835 	url = URL;
836 
837 	/* if the A flag is set, we only get one try */
838 	n = noredirect ? 1 : MAX_REDIRECT;
839 	i = 0;
840 
841 	e = HTTP_PROTOCOL_ERROR;
842 	need_auth = 0;
843 	do {
844 		new = NULL;
845 		chunked = 0;
846 		offset = 0;
847 		clength = -1;
848 		length = -1;
849 		size = -1;
850 		mtime = 0;
851 
852 		/* check port */
853 		if (!url->port)
854 			url->port = fetch_default_port(url->scheme);
855 
856 		/* were we redirected to an FTP URL? */
857 		if (purl == NULL && strcmp(url->scheme, SCHEME_FTP) == 0) {
858 			if (strcmp(op, "GET") == 0)
859 				return (ftp_request(url, "RETR", us, purl, flags));
860 			else if (strcmp(op, "HEAD") == 0)
861 				return (ftp_request(url, "STAT", us, purl, flags));
862 		}
863 
864 		/* connect to server or proxy */
865 		if ((conn = http_connect(url, purl, flags)) == NULL)
866 			goto ouch;
867 
868 		host = url->host;
869 #ifdef INET6
870 		if (strchr(url->host, ':')) {
871 			snprintf(hbuf, sizeof(hbuf), "[%s]", url->host);
872 			host = hbuf;
873 		}
874 #endif
875 		if (url->port != fetch_default_port(url->scheme)) {
876 			if (host != hbuf) {
877 				strcpy(hbuf, host);
878 				host = hbuf;
879 			}
880 			snprintf(hbuf + strlen(hbuf),
881 			    sizeof(hbuf) - strlen(hbuf), ":%d", url->port);
882 		}
883 
884 		/* send request */
885 		if (verbose)
886 			fetch_info("requesting %s://%s%s",
887 			    url->scheme, host, url->doc);
888 		if (purl) {
889 			http_cmd(conn, "%s %s://%s%s HTTP/1.1",
890 			    op, url->scheme, host, url->doc);
891 		} else {
892 			http_cmd(conn, "%s %s HTTP/1.1",
893 			    op, url->doc);
894 		}
895 
896 		if (ims && url->ims_time) {
897 			timestruct = gmtime((time_t *)&url->ims_time);
898 			(void)strftime(timebuf, 80, "%a, %d %b %Y %T GMT",
899 			    timestruct);
900 			if (verbose)
901 				fetch_info("If-Modified-Since: %s", timebuf);
902 			http_cmd(conn, "If-Modified-Since: %s", timebuf);
903 		}
904 		/* virtual host */
905 		http_cmd(conn, "Host: %s", host);
906 
907 		/* proxy authorization */
908 		if (purl) {
909 			if (*purl->user || *purl->pwd)
910 				http_basic_auth(conn, "Proxy-Authorization",
911 				    purl->user, purl->pwd);
912 			else if ((p = getenv("HTTP_PROXY_AUTH")) != NULL && *p != '\0')
913 				http_authorize(conn, "Proxy-Authorization", p);
914 		}
915 
916 		/* server authorization */
917 		if (need_auth || *url->user || *url->pwd) {
918 			if (*url->user || *url->pwd)
919 				http_basic_auth(conn, "Authorization", url->user, url->pwd);
920 			else if ((p = getenv("HTTP_AUTH")) != NULL && *p != '\0')
921 				http_authorize(conn, "Authorization", p);
922 			else if (fetchAuthMethod && fetchAuthMethod(url) == 0) {
923 				http_basic_auth(conn, "Authorization", url->user, url->pwd);
924 			} else {
925 				http_seterr(HTTP_NEED_AUTH);
926 				goto ouch;
927 			}
928 		}
929 
930 		/* other headers */
931 		if ((p = getenv("HTTP_REFERER")) != NULL && *p != '\0') {
932 			if (strcasecmp(p, "auto") == 0)
933 				http_cmd(conn, "Referer: %s://%s%s",
934 				    url->scheme, host, url->doc);
935 			else
936 				http_cmd(conn, "Referer: %s", p);
937 		}
938 		if ((p = getenv("HTTP_USER_AGENT")) != NULL && *p != '\0')
939 			http_cmd(conn, "User-Agent: %s", p);
940 		else
941 			http_cmd(conn, "User-Agent: %s " _LIBFETCH_VER, getprogname());
942 		if (url->offset > 0)
943 			http_cmd(conn, "Range: bytes=%lld-", (long long)url->offset);
944 		http_cmd(conn, "Connection: close");
945 		http_cmd(conn, "%s", "");
946 
947 		/*
948 		 * Force the queued request to be dispatched.  Normally, one
949 		 * would do this with shutdown(2) but squid proxies can be
950 		 * configured to disallow such half-closed connections.  To
951 		 * be compatible with such configurations, fiddle with socket
952 		 * options to force the pending data to be written.
953 		 */
954 		val = 0;
955 		setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val,
956 			   sizeof(val));
957 		val = 1;
958 		setsockopt(conn->sd, IPPROTO_TCP, TCP_NODELAY, &val,
959 			   sizeof(val));
960 
961 		/* get reply */
962 		switch (http_get_reply(conn)) {
963 		case HTTP_OK:
964 		case HTTP_PARTIAL:
965 		case HTTP_NOT_MODIFIED:
966 			/* fine */
967 			break;
968 		case HTTP_MOVED_PERM:
969 		case HTTP_MOVED_TEMP:
970 		case HTTP_SEE_OTHER:
971 			/*
972 			 * Not so fine, but we still have to read the
973 			 * headers to get the new location.
974 			 */
975 			break;
976 		case HTTP_NEED_AUTH:
977 			if (need_auth) {
978 				/*
979 				 * We already sent out authorization code,
980 				 * so there's nothing more we can do.
981 				 */
982 				http_seterr(conn->err);
983 				goto ouch;
984 			}
985 			/* try again, but send the password this time */
986 			if (verbose)
987 				fetch_info("server requires authorization");
988 			break;
989 		case HTTP_NEED_PROXY_AUTH:
990 			/*
991 			 * If we're talking to a proxy, we already sent
992 			 * our proxy authorization code, so there's
993 			 * nothing more we can do.
994 			 */
995 			http_seterr(conn->err);
996 			goto ouch;
997 		case HTTP_BAD_RANGE:
998 			/*
999 			 * This can happen if we ask for 0 bytes because
1000 			 * we already have the whole file.  Consider this
1001 			 * a success for now, and check sizes later.
1002 			 */
1003 			break;
1004 		case HTTP_PROTOCOL_ERROR:
1005 			/* fall through */
1006 		case -1:
1007 			fetch_syserr();
1008 			goto ouch;
1009 		default:
1010 			http_seterr(conn->err);
1011 			if (!verbose)
1012 				goto ouch;
1013 			/* fall through so we can get the full error message */
1014 		}
1015 
1016 		/* get headers */
1017 		do {
1018 			switch ((h = http_next_header(conn, &p))) {
1019 			case hdr_syserror:
1020 				fetch_syserr();
1021 				goto ouch;
1022 			case hdr_error:
1023 				http_seterr(HTTP_PROTOCOL_ERROR);
1024 				goto ouch;
1025 			case hdr_content_length:
1026 				http_parse_length(p, &clength);
1027 				break;
1028 			case hdr_content_range:
1029 				http_parse_range(p, &offset, &length, &size);
1030 				break;
1031 			case hdr_last_modified:
1032 				http_parse_mtime(p, &mtime);
1033 				break;
1034 			case hdr_location:
1035 				if (!HTTP_REDIRECT(conn->err))
1036 					break;
1037 				if (new)
1038 					free(new);
1039 				if (verbose)
1040 					fetch_info("%d redirect to %s", conn->err, p);
1041 				if (*p == '/')
1042 					/* absolute path */
1043 					new = fetchMakeURL(url->scheme, url->host, url->port, p,
1044 					    url->user, url->pwd);
1045 				else
1046 					new = fetchParseURL(p);
1047 				if (new == NULL) {
1048 					/* XXX should set an error code */
1049 					DEBUG(fprintf(stderr, "failed to parse new URL\n"));
1050 					goto ouch;
1051 				}
1052 				if (!*new->user && !*new->pwd) {
1053 					strcpy(new->user, url->user);
1054 					strcpy(new->pwd, url->pwd);
1055 				}
1056 				new->offset = url->offset;
1057 				new->length = url->length;
1058 				break;
1059 			case hdr_transfer_encoding:
1060 				/* XXX weak test*/
1061 				chunked = (strcasecmp(p, "chunked") == 0);
1062 				break;
1063 			case hdr_www_authenticate:
1064 				if (conn->err != HTTP_NEED_AUTH)
1065 					break;
1066 				/* if we were smarter, we'd check the method and realm */
1067 				break;
1068 			case hdr_end:
1069 				/* fall through */
1070 			case hdr_unknown:
1071 				/* ignore */
1072 				break;
1073 			}
1074 		} while (h > hdr_end);
1075 
1076 		/* we need to provide authentication */
1077 		if (conn->err == HTTP_NEED_AUTH) {
1078 			e = conn->err;
1079 			need_auth = 1;
1080 			fetch_close(conn);
1081 			conn = NULL;
1082 			continue;
1083 		}
1084 
1085 		/* requested range not satisfiable */
1086 		if (conn->err == HTTP_BAD_RANGE) {
1087 			if (url->offset == size && url->length == 0) {
1088 				/* asked for 0 bytes; fake it */
1089 				offset = url->offset;
1090 				clength = -1;
1091 				conn->err = HTTP_OK;
1092 				break;
1093 			} else {
1094 				http_seterr(conn->err);
1095 				goto ouch;
1096 			}
1097 		}
1098 
1099 		/* we have a hit or an error */
1100 		if (conn->err == HTTP_OK
1101 		    || conn->err == HTTP_NOT_MODIFIED
1102 		    || conn->err == HTTP_PARTIAL
1103 		    || HTTP_ERROR(conn->err))
1104 			break;
1105 
1106 		/* all other cases: we got a redirect */
1107 		e = conn->err;
1108 		need_auth = 0;
1109 		fetch_close(conn);
1110 		conn = NULL;
1111 		if (!new) {
1112 			DEBUG(fprintf(stderr, "redirect with no new location\n"));
1113 			break;
1114 		}
1115 		if (url != URL)
1116 			fetchFreeURL(url);
1117 		url = new;
1118 	} while (++i < n);
1119 
1120 	/* we failed, or ran out of retries */
1121 	if (conn == NULL) {
1122 		http_seterr(e);
1123 		goto ouch;
1124 	}
1125 
1126 	DEBUG(fprintf(stderr, "offset %lld, length %lld,"
1127 		  " size %lld, clength %lld\n",
1128 		  (long long)offset, (long long)length,
1129 		  (long long)size, (long long)clength));
1130 
1131 	if (conn->err == HTTP_NOT_MODIFIED) {
1132 		http_seterr(HTTP_NOT_MODIFIED);
1133 		return (NULL);
1134 	}
1135 
1136 	/* check for inconsistencies */
1137 	if (clength != -1 && length != -1 && clength != length) {
1138 		http_seterr(HTTP_PROTOCOL_ERROR);
1139 		goto ouch;
1140 	}
1141 	if (clength == -1)
1142 		clength = length;
1143 	if (clength != -1)
1144 		length = offset + clength;
1145 	if (length != -1 && size != -1 && length != size) {
1146 		http_seterr(HTTP_PROTOCOL_ERROR);
1147 		goto ouch;
1148 	}
1149 	if (size == -1)
1150 		size = length;
1151 
1152 	/* fill in stats */
1153 	if (us) {
1154 		us->size = size;
1155 		us->atime = us->mtime = mtime;
1156 	}
1157 
1158 	/* too far? */
1159 	if (URL->offset > 0 && offset > URL->offset) {
1160 		http_seterr(HTTP_PROTOCOL_ERROR);
1161 		goto ouch;
1162 	}
1163 
1164 	/* report back real offset and size */
1165 	URL->offset = offset;
1166 	URL->length = clength;
1167 
1168 	/* wrap it up in a FILE */
1169 	if ((f = http_funopen(conn, chunked)) == NULL) {
1170 		fetch_syserr();
1171 		goto ouch;
1172 	}
1173 
1174 	if (url != URL)
1175 		fetchFreeURL(url);
1176 	if (purl)
1177 		fetchFreeURL(purl);
1178 
1179 	if (HTTP_ERROR(conn->err)) {
1180 		http_print_html(stderr, f);
1181 		fclose(f);
1182 		f = NULL;
1183 	}
1184 
1185 	return (f);
1186 
1187 ouch:
1188 	if (url != URL)
1189 		fetchFreeURL(url);
1190 	if (purl)
1191 		fetchFreeURL(purl);
1192 	if (conn != NULL)
1193 		fetch_close(conn);
1194 	return (NULL);
1195 }
1196 
1197 
1198 /*****************************************************************************
1199  * Entry points
1200  */
1201 
1202 /*
1203  * Retrieve and stat a file by HTTP
1204  */
1205 FILE *
1206 fetchXGetHTTP(struct url *URL, struct url_stat *us, const char *flags)
1207 {
1208 	return (http_request(URL, "GET", us, http_get_proxy(URL, flags), flags));
1209 }
1210 
1211 /*
1212  * Retrieve a file by HTTP
1213  */
1214 FILE *
1215 fetchGetHTTP(struct url *URL, const char *flags)
1216 {
1217 	return (fetchXGetHTTP(URL, NULL, flags));
1218 }
1219 
1220 /*
1221  * Store a file by HTTP
1222  */
1223 FILE *
1224 fetchPutHTTP(struct url *URL __unused, const char *flags __unused)
1225 {
1226 	warnx("fetchPutHTTP(): not implemented");
1227 	return (NULL);
1228 }
1229 
1230 /*
1231  * Get an HTTP document's metadata
1232  */
1233 int
1234 fetchStatHTTP(struct url *URL, struct url_stat *us, const char *flags)
1235 {
1236 	FILE *f;
1237 
1238 	f = http_request(URL, "HEAD", us, http_get_proxy(URL, flags), flags);
1239 	if (f == NULL)
1240 		return (-1);
1241 	fclose(f);
1242 	return (0);
1243 }
1244 
1245 /*
1246  * List a directory
1247  */
1248 struct url_ent *
1249 fetchListHTTP(struct url *url __unused, const char *flags __unused)
1250 {
1251 	warnx("fetchListHTTP(): not implemented");
1252 	return (NULL);
1253 }
1254