xref: /freebsd/lib/libfetch/http.c (revision 7750ad47a9a7dbc83f87158464170c8640723293)
1 /*-
2  * Copyright (c) 2000-2011 Dag-Erling Smørgrav
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 #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 #include <md5.h>
80 
81 #include <netinet/in.h>
82 #include <netinet/tcp.h>
83 
84 #include "fetch.h"
85 #include "common.h"
86 #include "httperr.h"
87 
88 /* Maximum number of redirects to follow */
89 #define MAX_REDIRECT 5
90 
91 /* Symbolic names for reply codes we care about */
92 #define HTTP_OK			200
93 #define HTTP_PARTIAL		206
94 #define HTTP_MOVED_PERM		301
95 #define HTTP_MOVED_TEMP		302
96 #define HTTP_SEE_OTHER		303
97 #define HTTP_NOT_MODIFIED	304
98 #define HTTP_TEMP_REDIRECT	307
99 #define HTTP_NEED_AUTH		401
100 #define HTTP_NEED_PROXY_AUTH	407
101 #define HTTP_BAD_RANGE		416
102 #define HTTP_PROTOCOL_ERROR	999
103 
104 #define HTTP_REDIRECT(xyz) ((xyz) == HTTP_MOVED_PERM \
105 			    || (xyz) == HTTP_MOVED_TEMP \
106 			    || (xyz) == HTTP_TEMP_REDIRECT \
107 			    || (xyz) == HTTP_SEE_OTHER)
108 
109 #define HTTP_ERROR(xyz) ((xyz) > 400 && (xyz) < 599)
110 
111 
112 /*****************************************************************************
113  * I/O functions for decoding chunked streams
114  */
115 
116 struct httpio
117 {
118 	conn_t		*conn;		/* connection */
119 	int		 chunked;	/* chunked mode */
120 	char		*buf;		/* chunk buffer */
121 	size_t		 bufsize;	/* size of chunk buffer */
122 	ssize_t		 buflen;	/* amount of data currently in buffer */
123 	int		 bufpos;	/* current read offset in buffer */
124 	int		 eof;		/* end-of-file flag */
125 	int		 error;		/* error flag */
126 	size_t		 chunksize;	/* remaining size of current chunk */
127 #ifndef NDEBUG
128 	size_t		 total;
129 #endif
130 };
131 
132 /*
133  * Get next chunk header
134  */
135 static int
136 http_new_chunk(struct httpio *io)
137 {
138 	char *p;
139 
140 	if (fetch_getln(io->conn) == -1)
141 		return (-1);
142 
143 	if (io->conn->buflen < 2 || !isxdigit((unsigned char)*io->conn->buf))
144 		return (-1);
145 
146 	for (p = io->conn->buf; *p && !isspace((unsigned char)*p); ++p) {
147 		if (*p == ';')
148 			break;
149 		if (!isxdigit((unsigned char)*p))
150 			return (-1);
151 		if (isdigit((unsigned char)*p)) {
152 			io->chunksize = io->chunksize * 16 +
153 			    *p - '0';
154 		} else {
155 			io->chunksize = io->chunksize * 16 +
156 			    10 + tolower((unsigned char)*p) - 'a';
157 		}
158 	}
159 
160 #ifndef NDEBUG
161 	if (fetchDebug) {
162 		io->total += io->chunksize;
163 		if (io->chunksize == 0)
164 			fprintf(stderr, "%s(): end of last chunk\n", __func__);
165 		else
166 			fprintf(stderr, "%s(): new chunk: %lu (%lu)\n",
167 			    __func__, (unsigned long)io->chunksize,
168 			    (unsigned long)io->total);
169 	}
170 #endif
171 
172 	return (io->chunksize);
173 }
174 
175 /*
176  * Grow the input buffer to at least len bytes
177  */
178 static inline int
179 http_growbuf(struct httpio *io, size_t len)
180 {
181 	char *tmp;
182 
183 	if (io->bufsize >= len)
184 		return (0);
185 
186 	if ((tmp = realloc(io->buf, len)) == NULL)
187 		return (-1);
188 	io->buf = tmp;
189 	io->bufsize = len;
190 	return (0);
191 }
192 
193 /*
194  * Fill the input buffer, do chunk decoding on the fly
195  */
196 static int
197 http_fillbuf(struct httpio *io, size_t len)
198 {
199 	ssize_t nbytes;
200 
201 	if (io->error)
202 		return (-1);
203 	if (io->eof)
204 		return (0);
205 
206 	if (io->chunked == 0) {
207 		if (http_growbuf(io, len) == -1)
208 			return (-1);
209 		if ((nbytes = fetch_read(io->conn, io->buf, len)) == -1) {
210 			io->error = errno;
211 			return (-1);
212 		}
213 		io->buflen = nbytes;
214 		io->bufpos = 0;
215 		return (io->buflen);
216 	}
217 
218 	if (io->chunksize == 0) {
219 		switch (http_new_chunk(io)) {
220 		case -1:
221 			io->error = 1;
222 			return (-1);
223 		case 0:
224 			io->eof = 1;
225 			return (0);
226 		}
227 	}
228 
229 	if (len > io->chunksize)
230 		len = io->chunksize;
231 	if (http_growbuf(io, len) == -1)
232 		return (-1);
233 	if ((nbytes = fetch_read(io->conn, io->buf, len)) == -1) {
234 		io->error = errno;
235 		return (-1);
236 	}
237 	io->buflen = nbytes;
238 	io->chunksize -= io->buflen;
239 
240 	if (io->chunksize == 0) {
241 		char endl[2];
242 
243 		if (fetch_read(io->conn, endl, 2) != 2 ||
244 		    endl[0] != '\r' || endl[1] != '\n')
245 			return (-1);
246 	}
247 
248 	io->bufpos = 0;
249 
250 	return (io->buflen);
251 }
252 
253 /*
254  * Read function
255  */
256 static int
257 http_readfn(void *v, char *buf, int len)
258 {
259 	struct httpio *io = (struct httpio *)v;
260 	int l, pos;
261 
262 	if (io->error)
263 		return (-1);
264 	if (io->eof)
265 		return (0);
266 
267 	for (pos = 0; len > 0; pos += l, len -= l) {
268 		/* empty buffer */
269 		if (!io->buf || io->bufpos == io->buflen)
270 			if (http_fillbuf(io, len) < 1)
271 				break;
272 		l = io->buflen - io->bufpos;
273 		if (len < l)
274 			l = len;
275 		memcpy(buf + pos, io->buf + io->bufpos, l);
276 		io->bufpos += l;
277 	}
278 
279 	if (!pos && io->error) {
280 		if (io->error == EINTR)
281 			io->error = 0;
282 		return (-1);
283 	}
284 	return (pos);
285 }
286 
287 /*
288  * Write function
289  */
290 static int
291 http_writefn(void *v, const char *buf, int len)
292 {
293 	struct httpio *io = (struct httpio *)v;
294 
295 	return (fetch_write(io->conn, buf, len));
296 }
297 
298 /*
299  * Close function
300  */
301 static int
302 http_closefn(void *v)
303 {
304 	struct httpio *io = (struct httpio *)v;
305 	int r;
306 
307 	r = fetch_close(io->conn);
308 	if (io->buf)
309 		free(io->buf);
310 	free(io);
311 	return (r);
312 }
313 
314 /*
315  * Wrap a file descriptor up
316  */
317 static FILE *
318 http_funopen(conn_t *conn, int chunked)
319 {
320 	struct httpio *io;
321 	FILE *f;
322 
323 	if ((io = calloc(1, sizeof(*io))) == NULL) {
324 		fetch_syserr();
325 		return (NULL);
326 	}
327 	io->conn = conn;
328 	io->chunked = chunked;
329 	f = funopen(io, http_readfn, http_writefn, NULL, http_closefn);
330 	if (f == NULL) {
331 		fetch_syserr();
332 		free(io);
333 		return (NULL);
334 	}
335 	return (f);
336 }
337 
338 
339 /*****************************************************************************
340  * Helper functions for talking to the server and parsing its replies
341  */
342 
343 /* Header types */
344 typedef enum {
345 	hdr_syserror = -2,
346 	hdr_error = -1,
347 	hdr_end = 0,
348 	hdr_unknown = 1,
349 	hdr_content_length,
350 	hdr_content_range,
351 	hdr_last_modified,
352 	hdr_location,
353 	hdr_transfer_encoding,
354 	hdr_www_authenticate,
355 	hdr_proxy_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_proxy_authenticate,	"Proxy-Authenticate" },
370 	{ hdr_unknown,			NULL },
371 };
372 
373 /*
374  * Send a formatted line; optionally echo to terminal
375  */
376 static int
377 http_cmd(conn_t *conn, const char *fmt, ...)
378 {
379 	va_list ap;
380 	size_t len;
381 	char *msg;
382 	int r;
383 
384 	va_start(ap, fmt);
385 	len = vasprintf(&msg, fmt, ap);
386 	va_end(ap);
387 
388 	if (msg == NULL) {
389 		errno = ENOMEM;
390 		fetch_syserr();
391 		return (-1);
392 	}
393 
394 	r = fetch_putln(conn, msg, len);
395 	free(msg);
396 
397 	if (r == -1) {
398 		fetch_syserr();
399 		return (-1);
400 	}
401 
402 	return (0);
403 }
404 
405 /*
406  * Get and parse status line
407  */
408 static int
409 http_get_reply(conn_t *conn)
410 {
411 	char *p;
412 
413 	if (fetch_getln(conn) == -1)
414 		return (-1);
415 	/*
416 	 * A valid status line looks like "HTTP/m.n xyz reason" where m
417 	 * and n are the major and minor protocol version numbers and xyz
418 	 * is the reply code.
419 	 * Unfortunately, there are servers out there (NCSA 1.5.1, to name
420 	 * just one) that do not send a version number, so we can't rely
421 	 * on finding one, but if we do, insist on it being 1.0 or 1.1.
422 	 * We don't care about the reason phrase.
423 	 */
424 	if (strncmp(conn->buf, "HTTP", 4) != 0)
425 		return (HTTP_PROTOCOL_ERROR);
426 	p = conn->buf + 4;
427 	if (*p == '/') {
428 		if (p[1] != '1' || p[2] != '.' || (p[3] != '0' && p[3] != '1'))
429 			return (HTTP_PROTOCOL_ERROR);
430 		p += 4;
431 	}
432 	if (*p != ' ' ||
433 	    !isdigit((unsigned char)p[1]) ||
434 	    !isdigit((unsigned char)p[2]) ||
435 	    !isdigit((unsigned char)p[3]))
436 		return (HTTP_PROTOCOL_ERROR);
437 
438 	conn->err = (p[1] - '0') * 100 + (p[2] - '0') * 10 + (p[3] - '0');
439 	return (conn->err);
440 }
441 
442 /*
443  * Check a header; if the type matches the given string, return a pointer
444  * to the beginning of the value.
445  */
446 static const char *
447 http_match(const char *str, const char *hdr)
448 {
449 	while (*str && *hdr &&
450 	    tolower((unsigned char)*str++) == tolower((unsigned char)*hdr++))
451 		/* nothing */;
452 	if (*str || *hdr != ':')
453 		return (NULL);
454 	while (*hdr && isspace((unsigned char)*++hdr))
455 		/* nothing */;
456 	return (hdr);
457 }
458 
459 
460 /*
461  * Get the next header and return the appropriate symbolic code.  We
462  * need to read one line ahead for checking for a continuation line
463  * belonging to the current header (continuation lines start with
464  * white space).
465  *
466  * We get called with a fresh line already in the conn buffer, either
467  * from the previous http_next_header() invocation, or, the first
468  * time, from a fetch_getln() performed by our caller.
469  *
470  * This stops when we encounter an empty line (we dont read beyond the header
471  * area).
472  *
473  * Note that the "headerbuf" is just a place to return the result. Its
474  * contents are not used for the next call. This means that no cleanup
475  * is needed when ie doing another connection, just call the cleanup when
476  * fully done to deallocate memory.
477  */
478 
479 /* Limit the max number of continuation lines to some reasonable value */
480 #define HTTP_MAX_CONT_LINES 10
481 
482 /* Place into which to build a header from one or several lines */
483 typedef struct {
484 	char	*buf;		/* buffer */
485 	size_t	 bufsize;	/* buffer size */
486 	size_t	 buflen;	/* length of buffer contents */
487 } http_headerbuf_t;
488 
489 static void
490 init_http_headerbuf(http_headerbuf_t *buf)
491 {
492 	buf->buf = NULL;
493 	buf->bufsize = 0;
494 	buf->buflen = 0;
495 }
496 
497 static void
498 clean_http_headerbuf(http_headerbuf_t *buf)
499 {
500 	if (buf->buf)
501 		free(buf->buf);
502 	init_http_headerbuf(buf);
503 }
504 
505 /* Remove whitespace at the end of the buffer */
506 static void
507 http_conn_trimright(conn_t *conn)
508 {
509 	while (conn->buflen &&
510 	       isspace((unsigned char)conn->buf[conn->buflen - 1]))
511 		conn->buflen--;
512 	conn->buf[conn->buflen] = '\0';
513 }
514 
515 static hdr_t
516 http_next_header(conn_t *conn, http_headerbuf_t *hbuf, const char **p)
517 {
518 	unsigned int i, len;
519 
520 	/*
521 	 * Have to do the stripping here because of the first line. So
522 	 * it's done twice for the subsequent lines. No big deal
523 	 */
524 	http_conn_trimright(conn);
525 	if (conn->buflen == 0)
526 		return (hdr_end);
527 
528 	/* Copy the line to the headerbuf */
529 	if (hbuf->bufsize < conn->buflen + 1) {
530 		if ((hbuf->buf = realloc(hbuf->buf, conn->buflen + 1)) == NULL)
531 			return (hdr_syserror);
532 		hbuf->bufsize = conn->buflen + 1;
533 	}
534 	strcpy(hbuf->buf, conn->buf);
535 	hbuf->buflen = conn->buflen;
536 
537 	/*
538 	 * Fetch possible continuation lines. Stop at 1st non-continuation
539 	 * and leave it in the conn buffer
540 	 */
541 	for (i = 0; i < HTTP_MAX_CONT_LINES; i++) {
542 		if (fetch_getln(conn) == -1)
543 			return (hdr_syserror);
544 
545 		/*
546 		 * Note: we carry on the idea from the previous version
547 		 * that a pure whitespace line is equivalent to an empty
548 		 * one (so it's not continuation and will be handled when
549 		 * we are called next)
550 		 */
551 		http_conn_trimright(conn);
552 		if (conn->buf[0] != ' ' && conn->buf[0] != "\t"[0])
553 			break;
554 
555 		/* Got a continuation line. Concatenate to previous */
556 		len = hbuf->buflen + conn->buflen;
557 		if (hbuf->bufsize < len + 1) {
558 			len *= 2;
559 			if ((hbuf->buf = realloc(hbuf->buf, len + 1)) == NULL)
560 				return (hdr_syserror);
561 			hbuf->bufsize = len + 1;
562 		}
563 		strcpy(hbuf->buf + hbuf->buflen, conn->buf);
564 		hbuf->buflen += conn->buflen;
565 	}
566 
567 	/*
568 	 * We could check for malformed headers but we don't really care.
569 	 * A valid header starts with a token immediately followed by a
570 	 * colon; a token is any sequence of non-control, non-whitespace
571 	 * characters except "()<>@,;:\\\"{}".
572 	 */
573 	for (i = 0; hdr_names[i].num != hdr_unknown; i++)
574 		if ((*p = http_match(hdr_names[i].name, hbuf->buf)) != NULL)
575 			return (hdr_names[i].num);
576 
577 	return (hdr_unknown);
578 }
579 
580 /**************************
581  * [Proxy-]Authenticate header parsing
582  */
583 
584 /*
585  * Read doublequote-delimited string into output buffer obuf (allocated
586  * by caller, whose responsibility it is to ensure that it's big enough)
587  * cp points to the first char after the initial '"'
588  * Handles \ quoting
589  * Returns pointer to the first char after the terminating double quote, or
590  * NULL for error.
591  */
592 static const char *
593 http_parse_headerstring(const char *cp, char *obuf)
594 {
595 	for (;;) {
596 		switch (*cp) {
597 		case 0: /* Unterminated string */
598 			*obuf = 0;
599 			return (NULL);
600 		case '"': /* Ending quote */
601 			*obuf = 0;
602 			return (++cp);
603 		case '\\':
604 			if (*++cp == 0) {
605 				*obuf = 0;
606 				return (NULL);
607 			}
608 			/* FALLTHROUGH */
609 		default:
610 			*obuf++ = *cp++;
611 		}
612 	}
613 }
614 
615 /* Http auth challenge schemes */
616 typedef enum {HTTPAS_UNKNOWN, HTTPAS_BASIC,HTTPAS_DIGEST} http_auth_schemes_t;
617 
618 /* Data holder for a Basic or Digest challenge. */
619 typedef struct {
620 	http_auth_schemes_t scheme;
621 	char	*realm;
622 	char	*qop;
623 	char	*nonce;
624 	char	*opaque;
625 	char	*algo;
626 	int	 stale;
627 	int	 nc; /* Nonce count */
628 } http_auth_challenge_t;
629 
630 static void
631 init_http_auth_challenge(http_auth_challenge_t *b)
632 {
633 	b->scheme = HTTPAS_UNKNOWN;
634 	b->realm = b->qop = b->nonce = b->opaque = b->algo = NULL;
635 	b->stale = b->nc = 0;
636 }
637 
638 static void
639 clean_http_auth_challenge(http_auth_challenge_t *b)
640 {
641 	if (b->realm)
642 		free(b->realm);
643 	if (b->qop)
644 		free(b->qop);
645 	if (b->nonce)
646 		free(b->nonce);
647 	if (b->opaque)
648 		free(b->opaque);
649 	if (b->algo)
650 		free(b->algo);
651 	init_http_auth_challenge(b);
652 }
653 
654 /* Data holder for an array of challenges offered in an http response. */
655 #define MAX_CHALLENGES 10
656 typedef struct {
657 	http_auth_challenge_t *challenges[MAX_CHALLENGES];
658 	int	count; /* Number of parsed challenges in the array */
659 	int	valid; /* We did parse an authenticate header */
660 } http_auth_challenges_t;
661 
662 static void
663 init_http_auth_challenges(http_auth_challenges_t *cs)
664 {
665 	int i;
666 	for (i = 0; i < MAX_CHALLENGES; i++)
667 		cs->challenges[i] = NULL;
668 	cs->count = cs->valid = 0;
669 }
670 
671 static void
672 clean_http_auth_challenges(http_auth_challenges_t *cs)
673 {
674 	int i;
675 	/* We rely on non-zero pointers being allocated, not on the count */
676 	for (i = 0; i < MAX_CHALLENGES; i++) {
677 		if (cs->challenges[i] != NULL) {
678 			clean_http_auth_challenge(cs->challenges[i]);
679 			free(cs->challenges[i]);
680 		}
681 	}
682 	init_http_auth_challenges(cs);
683 }
684 
685 /*
686  * Enumeration for lexical elements. Separators will be returned as their own
687  * ascii value
688  */
689 typedef enum {HTTPHL_WORD=256, HTTPHL_STRING=257, HTTPHL_END=258,
690 	      HTTPHL_ERROR = 259} http_header_lex_t;
691 
692 /*
693  * Determine what kind of token comes next and return possible value
694  * in buf, which is supposed to have been allocated big enough by
695  * caller. Advance input pointer and return element type.
696  */
697 static int
698 http_header_lex(const char **cpp, char *buf)
699 {
700 	size_t l;
701 	/* Eat initial whitespace */
702 	*cpp += strspn(*cpp, " \t");
703 	if (**cpp == 0)
704 		return (HTTPHL_END);
705 
706 	/* Separator ? */
707 	if (**cpp == ',' || **cpp == '=')
708 		return (*((*cpp)++));
709 
710 	/* String ? */
711 	if (**cpp == '"') {
712 		*cpp = http_parse_headerstring(++*cpp, buf);
713 		if (*cpp == NULL)
714 			return (HTTPHL_ERROR);
715 		return (HTTPHL_STRING);
716 	}
717 
718 	/* Read other token, until separator or whitespace */
719 	l = strcspn(*cpp, " \t,=");
720 	memcpy(buf, *cpp, l);
721 	buf[l] = 0;
722 	*cpp += l;
723 	return (HTTPHL_WORD);
724 }
725 
726 /*
727  * Read challenges from http xxx-authenticate header and accumulate them
728  * in the challenges list structure.
729  *
730  * Headers with multiple challenges are specified by rfc2617, but
731  * servers (ie: squid) often send them in separate headers instead,
732  * which in turn is forbidden by the http spec (multiple headers with
733  * the same name are only allowed for pure comma-separated lists, see
734  * rfc2616 sec 4.2).
735  *
736  * We support both approaches anyway
737  */
738 static int
739 http_parse_authenticate(const char *cp, http_auth_challenges_t *cs)
740 {
741 	int ret = -1;
742 	http_header_lex_t lex;
743 	char *key = malloc(strlen(cp) + 1);
744 	char *value = malloc(strlen(cp) + 1);
745 	char *buf = malloc(strlen(cp) + 1);
746 
747 	if (key == NULL || value == NULL || buf == NULL) {
748 		fetch_syserr();
749 		goto out;
750 	}
751 
752 	/* In any case we've seen the header and we set the valid bit */
753 	cs->valid = 1;
754 
755 	/* Need word first */
756 	lex = http_header_lex(&cp, key);
757 	if (lex != HTTPHL_WORD)
758 		goto out;
759 
760 	/* Loop on challenges */
761 	for (; cs->count < MAX_CHALLENGES; cs->count++) {
762 		cs->challenges[cs->count] =
763 			malloc(sizeof(http_auth_challenge_t));
764 		if (cs->challenges[cs->count] == NULL) {
765 			fetch_syserr();
766 			goto out;
767 		}
768 		init_http_auth_challenge(cs->challenges[cs->count]);
769 		if (!strcasecmp(key, "basic")) {
770 			cs->challenges[cs->count]->scheme = HTTPAS_BASIC;
771 		} else if (!strcasecmp(key, "digest")) {
772 			cs->challenges[cs->count]->scheme = HTTPAS_DIGEST;
773 		} else {
774 			cs->challenges[cs->count]->scheme = HTTPAS_UNKNOWN;
775 			/*
776 			 * Continue parsing as basic or digest may
777 			 * follow, and the syntax is the same for
778 			 * all. We'll just ignore this one when
779 			 * looking at the list
780 			 */
781 		}
782 
783 		/* Loop on attributes */
784 		for (;;) {
785 			/* Key */
786 			lex = http_header_lex(&cp, key);
787 			if (lex != HTTPHL_WORD)
788 				goto out;
789 
790 			/* Equal sign */
791 			lex = http_header_lex(&cp, buf);
792 			if (lex != '=')
793 				goto out;
794 
795 			/* Value */
796 			lex = http_header_lex(&cp, value);
797 			if (lex != HTTPHL_WORD && lex != HTTPHL_STRING)
798 				goto out;
799 
800 			if (!strcasecmp(key, "realm"))
801 				cs->challenges[cs->count]->realm =
802 					strdup(value);
803 			else if (!strcasecmp(key, "qop"))
804 				cs->challenges[cs->count]->qop =
805 					strdup(value);
806 			else if (!strcasecmp(key, "nonce"))
807 				cs->challenges[cs->count]->nonce =
808 					strdup(value);
809 			else if (!strcasecmp(key, "opaque"))
810 				cs->challenges[cs->count]->opaque =
811 					strdup(value);
812 			else if (!strcasecmp(key, "algorithm"))
813 				cs->challenges[cs->count]->algo =
814 					strdup(value);
815 			else if (!strcasecmp(key, "stale"))
816 				cs->challenges[cs->count]->stale =
817 					strcasecmp(value, "no");
818 			/* Else ignore unknown attributes */
819 
820 			/* Comma or Next challenge or End */
821 			lex = http_header_lex(&cp, key);
822 			/*
823 			 * If we get a word here, this is the beginning of the
824 			 * next challenge. Break the attributes loop
825 			 */
826 			if (lex == HTTPHL_WORD)
827 				break;
828 
829 			if (lex == HTTPHL_END) {
830 				/* End while looking for ',' is normal exit */
831 				cs->count++;
832 				ret = 0;
833 				goto out;
834 			}
835 			/* Anything else is an error */
836 			if (lex != ',')
837 				goto out;
838 
839 		} /* End attributes loop */
840 	} /* End challenge loop */
841 
842 	/*
843 	 * Challenges max count exceeded. This really can't happen
844 	 * with normal data, something's fishy -> error
845 	 */
846 
847 out:
848 	if (key)
849 		free(key);
850 	if (value)
851 		free(value);
852 	if (buf)
853 		free(buf);
854 	return (ret);
855 }
856 
857 
858 /*
859  * Parse a last-modified header
860  */
861 static int
862 http_parse_mtime(const char *p, time_t *mtime)
863 {
864 	char locale[64], *r;
865 	struct tm tm;
866 
867 	strncpy(locale, setlocale(LC_TIME, NULL), sizeof(locale));
868 	setlocale(LC_TIME, "C");
869 	r = strptime(p, "%a, %d %b %Y %H:%M:%S GMT", &tm);
870 	/* XXX should add support for date-2 and date-3 */
871 	setlocale(LC_TIME, locale);
872 	if (r == NULL)
873 		return (-1);
874 	DEBUG(fprintf(stderr, "last modified: [%04d-%02d-%02d "
875 		  "%02d:%02d:%02d]\n",
876 		  tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
877 		  tm.tm_hour, tm.tm_min, tm.tm_sec));
878 	*mtime = timegm(&tm);
879 	return (0);
880 }
881 
882 /*
883  * Parse a content-length header
884  */
885 static int
886 http_parse_length(const char *p, off_t *length)
887 {
888 	off_t len;
889 
890 	for (len = 0; *p && isdigit((unsigned char)*p); ++p)
891 		len = len * 10 + (*p - '0');
892 	if (*p)
893 		return (-1);
894 	DEBUG(fprintf(stderr, "content length: [%lld]\n",
895 	    (long long)len));
896 	*length = len;
897 	return (0);
898 }
899 
900 /*
901  * Parse a content-range header
902  */
903 static int
904 http_parse_range(const char *p, off_t *offset, off_t *length, off_t *size)
905 {
906 	off_t first, last, len;
907 
908 	if (strncasecmp(p, "bytes ", 6) != 0)
909 		return (-1);
910 	p += 6;
911 	if (*p == '*') {
912 		first = last = -1;
913 		++p;
914 	} else {
915 		for (first = 0; *p && isdigit((unsigned char)*p); ++p)
916 			first = first * 10 + *p - '0';
917 		if (*p != '-')
918 			return (-1);
919 		for (last = 0, ++p; *p && isdigit((unsigned char)*p); ++p)
920 			last = last * 10 + *p - '0';
921 	}
922 	if (first > last || *p != '/')
923 		return (-1);
924 	for (len = 0, ++p; *p && isdigit((unsigned char)*p); ++p)
925 		len = len * 10 + *p - '0';
926 	if (*p || len < last - first + 1)
927 		return (-1);
928 	if (first == -1) {
929 		DEBUG(fprintf(stderr, "content range: [*/%lld]\n",
930 		    (long long)len));
931 		*length = 0;
932 	} else {
933 		DEBUG(fprintf(stderr, "content range: [%lld-%lld/%lld]\n",
934 		    (long long)first, (long long)last, (long long)len));
935 		*length = last - first + 1;
936 	}
937 	*offset = first;
938 	*size = len;
939 	return (0);
940 }
941 
942 
943 /*****************************************************************************
944  * Helper functions for authorization
945  */
946 
947 /*
948  * Base64 encoding
949  */
950 static char *
951 http_base64(const char *src)
952 {
953 	static const char base64[] =
954 	    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
955 	    "abcdefghijklmnopqrstuvwxyz"
956 	    "0123456789+/";
957 	char *str, *dst;
958 	size_t l;
959 	int t, r;
960 
961 	l = strlen(src);
962 	if ((str = malloc(((l + 2) / 3) * 4 + 1)) == NULL)
963 		return (NULL);
964 	dst = str;
965 	r = 0;
966 
967 	while (l >= 3) {
968 		t = (src[0] << 16) | (src[1] << 8) | src[2];
969 		dst[0] = base64[(t >> 18) & 0x3f];
970 		dst[1] = base64[(t >> 12) & 0x3f];
971 		dst[2] = base64[(t >> 6) & 0x3f];
972 		dst[3] = base64[(t >> 0) & 0x3f];
973 		src += 3; l -= 3;
974 		dst += 4; r += 4;
975 	}
976 
977 	switch (l) {
978 	case 2:
979 		t = (src[0] << 16) | (src[1] << 8);
980 		dst[0] = base64[(t >> 18) & 0x3f];
981 		dst[1] = base64[(t >> 12) & 0x3f];
982 		dst[2] = base64[(t >> 6) & 0x3f];
983 		dst[3] = '=';
984 		dst += 4;
985 		r += 4;
986 		break;
987 	case 1:
988 		t = src[0] << 16;
989 		dst[0] = base64[(t >> 18) & 0x3f];
990 		dst[1] = base64[(t >> 12) & 0x3f];
991 		dst[2] = dst[3] = '=';
992 		dst += 4;
993 		r += 4;
994 		break;
995 	case 0:
996 		break;
997 	}
998 
999 	*dst = 0;
1000 	return (str);
1001 }
1002 
1003 
1004 /*
1005  * Extract authorization parameters from environment value.
1006  * The value is like scheme:realm:user:pass
1007  */
1008 typedef struct {
1009 	char	*scheme;
1010 	char	*realm;
1011 	char	*user;
1012 	char	*password;
1013 } http_auth_params_t;
1014 
1015 static void
1016 init_http_auth_params(http_auth_params_t *s)
1017 {
1018 	s->scheme = s->realm = s->user = s->password = 0;
1019 }
1020 
1021 static void
1022 clean_http_auth_params(http_auth_params_t *s)
1023 {
1024 	if (s->scheme)
1025 		free(s->scheme);
1026 	if (s->realm)
1027 		free(s->realm);
1028 	if (s->user)
1029 		free(s->user);
1030 	if (s->password)
1031 		free(s->password);
1032 	init_http_auth_params(s);
1033 }
1034 
1035 static int
1036 http_authfromenv(const char *p, http_auth_params_t *parms)
1037 {
1038 	int ret = -1;
1039 	char *v, *ve;
1040 	char *str = strdup(p);
1041 
1042 	if (str == NULL) {
1043 		fetch_syserr();
1044 		return (-1);
1045 	}
1046 	v = str;
1047 
1048 	if ((ve = strchr(v, ':')) == NULL)
1049 		goto out;
1050 
1051 	*ve = 0;
1052 	if ((parms->scheme = strdup(v)) == NULL) {
1053 		fetch_syserr();
1054 		goto out;
1055 	}
1056 	v = ve + 1;
1057 
1058 	if ((ve = strchr(v, ':')) == NULL)
1059 		goto out;
1060 
1061 	*ve = 0;
1062 	if ((parms->realm = strdup(v)) == NULL) {
1063 		fetch_syserr();
1064 		goto out;
1065 	}
1066 	v = ve + 1;
1067 
1068 	if ((ve = strchr(v, ':')) == NULL)
1069 		goto out;
1070 
1071 	*ve = 0;
1072 	if ((parms->user = strdup(v)) == NULL) {
1073 		fetch_syserr();
1074 		goto out;
1075 	}
1076 	v = ve + 1;
1077 
1078 
1079 	if ((parms->password = strdup(v)) == NULL) {
1080 		fetch_syserr();
1081 		goto out;
1082 	}
1083 	ret = 0;
1084 out:
1085 	if (ret == -1)
1086 		clean_http_auth_params(parms);
1087 	if (str)
1088 		free(str);
1089 	return (ret);
1090 }
1091 
1092 
1093 /*
1094  * Digest response: the code to compute the digest is taken from the
1095  * sample implementation in RFC2616
1096  */
1097 #define IN const
1098 #define OUT
1099 
1100 #define HASHLEN 16
1101 typedef char HASH[HASHLEN];
1102 #define HASHHEXLEN 32
1103 typedef char HASHHEX[HASHHEXLEN+1];
1104 
1105 static const char *hexchars = "0123456789abcdef";
1106 static void
1107 CvtHex(IN HASH Bin, OUT HASHHEX Hex)
1108 {
1109 	unsigned short i;
1110 	unsigned char j;
1111 
1112 	for (i = 0; i < HASHLEN; i++) {
1113 		j = (Bin[i] >> 4) & 0xf;
1114 		Hex[i*2] = hexchars[j];
1115 		j = Bin[i] & 0xf;
1116 		Hex[i*2+1] = hexchars[j];
1117 	};
1118 	Hex[HASHHEXLEN] = '\0';
1119 };
1120 
1121 /* calculate H(A1) as per spec */
1122 static void
1123 DigestCalcHA1(
1124 	IN char * pszAlg,
1125 	IN char * pszUserName,
1126 	IN char * pszRealm,
1127 	IN char * pszPassword,
1128 	IN char * pszNonce,
1129 	IN char * pszCNonce,
1130 	OUT HASHHEX SessionKey
1131 	)
1132 {
1133 	MD5_CTX Md5Ctx;
1134 	HASH HA1;
1135 
1136 	MD5Init(&Md5Ctx);
1137 	MD5Update(&Md5Ctx, pszUserName, strlen(pszUserName));
1138 	MD5Update(&Md5Ctx, ":", 1);
1139 	MD5Update(&Md5Ctx, pszRealm, strlen(pszRealm));
1140 	MD5Update(&Md5Ctx, ":", 1);
1141 	MD5Update(&Md5Ctx, pszPassword, strlen(pszPassword));
1142 	MD5Final(HA1, &Md5Ctx);
1143 	if (strcasecmp(pszAlg, "md5-sess") == 0) {
1144 
1145 		MD5Init(&Md5Ctx);
1146 		MD5Update(&Md5Ctx, HA1, HASHLEN);
1147 		MD5Update(&Md5Ctx, ":", 1);
1148 		MD5Update(&Md5Ctx, pszNonce, strlen(pszNonce));
1149 		MD5Update(&Md5Ctx, ":", 1);
1150 		MD5Update(&Md5Ctx, pszCNonce, strlen(pszCNonce));
1151 		MD5Final(HA1, &Md5Ctx);
1152 	};
1153 	CvtHex(HA1, SessionKey);
1154 }
1155 
1156 /* calculate request-digest/response-digest as per HTTP Digest spec */
1157 static void
1158 DigestCalcResponse(
1159 	IN HASHHEX HA1,           /* H(A1) */
1160 	IN char * pszNonce,       /* nonce from server */
1161 	IN char * pszNonceCount,  /* 8 hex digits */
1162 	IN char * pszCNonce,      /* client nonce */
1163 	IN char * pszQop,         /* qop-value: "", "auth", "auth-int" */
1164 	IN char * pszMethod,      /* method from the request */
1165 	IN char * pszDigestUri,   /* requested URL */
1166 	IN HASHHEX HEntity,       /* H(entity body) if qop="auth-int" */
1167 	OUT HASHHEX Response      /* request-digest or response-digest */
1168 	)
1169 {
1170 /*	DEBUG(fprintf(stderr,
1171 		      "Calc: HA1[%s] Nonce[%s] qop[%s] method[%s] URI[%s]\n",
1172 		      HA1, pszNonce, pszQop, pszMethod, pszDigestUri));*/
1173 	MD5_CTX Md5Ctx;
1174 	HASH HA2;
1175 	HASH RespHash;
1176 	HASHHEX HA2Hex;
1177 
1178 	// calculate H(A2)
1179 	MD5Init(&Md5Ctx);
1180 	MD5Update(&Md5Ctx, pszMethod, strlen(pszMethod));
1181 	MD5Update(&Md5Ctx, ":", 1);
1182 	MD5Update(&Md5Ctx, pszDigestUri, strlen(pszDigestUri));
1183 	if (strcasecmp(pszQop, "auth-int") == 0) {
1184 		MD5Update(&Md5Ctx, ":", 1);
1185 		MD5Update(&Md5Ctx, HEntity, HASHHEXLEN);
1186 	};
1187 	MD5Final(HA2, &Md5Ctx);
1188 	CvtHex(HA2, HA2Hex);
1189 
1190 	// calculate response
1191 	MD5Init(&Md5Ctx);
1192 	MD5Update(&Md5Ctx, HA1, HASHHEXLEN);
1193 	MD5Update(&Md5Ctx, ":", 1);
1194 	MD5Update(&Md5Ctx, pszNonce, strlen(pszNonce));
1195 	MD5Update(&Md5Ctx, ":", 1);
1196 	if (*pszQop) {
1197 		MD5Update(&Md5Ctx, pszNonceCount, strlen(pszNonceCount));
1198 		MD5Update(&Md5Ctx, ":", 1);
1199 		MD5Update(&Md5Ctx, pszCNonce, strlen(pszCNonce));
1200 		MD5Update(&Md5Ctx, ":", 1);
1201 		MD5Update(&Md5Ctx, pszQop, strlen(pszQop));
1202 		MD5Update(&Md5Ctx, ":", 1);
1203 	};
1204 	MD5Update(&Md5Ctx, HA2Hex, HASHHEXLEN);
1205 	MD5Final(RespHash, &Md5Ctx);
1206 	CvtHex(RespHash, Response);
1207 }
1208 
1209 /*
1210  * Generate/Send a Digest authorization header
1211  * This looks like: [Proxy-]Authorization: credentials
1212  *
1213  *  credentials      = "Digest" digest-response
1214  *  digest-response  = 1#( username | realm | nonce | digest-uri
1215  *                      | response | [ algorithm ] | [cnonce] |
1216  *                      [opaque] | [message-qop] |
1217  *                          [nonce-count]  | [auth-param] )
1218  *  username         = "username" "=" username-value
1219  *  username-value   = quoted-string
1220  *  digest-uri       = "uri" "=" digest-uri-value
1221  *  digest-uri-value = request-uri   ; As specified by HTTP/1.1
1222  *  message-qop      = "qop" "=" qop-value
1223  *  cnonce           = "cnonce" "=" cnonce-value
1224  *  cnonce-value     = nonce-value
1225  *  nonce-count      = "nc" "=" nc-value
1226  *  nc-value         = 8LHEX
1227  *  response         = "response" "=" request-digest
1228  *  request-digest = <"> 32LHEX <">
1229  */
1230 static int
1231 http_digest_auth(conn_t *conn, const char *hdr, http_auth_challenge_t *c,
1232 		 http_auth_params_t *parms, struct url *url)
1233 {
1234 	int r;
1235 	char noncecount[10];
1236 	char cnonce[40];
1237 	char *options = 0;
1238 
1239 	if (!c->realm || !c->nonce) {
1240 		DEBUG(fprintf(stderr, "realm/nonce not set in challenge\n"));
1241 		return(-1);
1242 	}
1243 	if (!c->algo)
1244 		c->algo = strdup("");
1245 
1246 	if (asprintf(&options, "%s%s%s%s",
1247 		     *c->algo? ",algorithm=" : "", c->algo,
1248 		     c->opaque? ",opaque=" : "", c->opaque?c->opaque:"")== -1)
1249 		return (-1);
1250 
1251 	if (!c->qop) {
1252 		c->qop = strdup("");
1253 		*noncecount = 0;
1254 		*cnonce = 0;
1255 	} else {
1256 		c->nc++;
1257 		sprintf(noncecount, "%08x", c->nc);
1258 		/* We don't try very hard with the cnonce ... */
1259 		sprintf(cnonce, "%x%lx", getpid(), (unsigned long)time(0));
1260 	}
1261 
1262 	HASHHEX HA1;
1263 	DigestCalcHA1(c->algo, parms->user, c->realm,
1264 		      parms->password, c->nonce, cnonce, HA1);
1265 	DEBUG(fprintf(stderr, "HA1: [%s]\n", HA1));
1266 	HASHHEX digest;
1267 	DigestCalcResponse(HA1, c->nonce, noncecount, cnonce, c->qop,
1268 			   "GET", url->doc, "", digest);
1269 
1270 	if (c->qop[0]) {
1271 		r = http_cmd(conn, "%s: Digest username=\"%s\",realm=\"%s\","
1272 			     "nonce=\"%s\",uri=\"%s\",response=\"%s\","
1273 			     "qop=\"auth\", cnonce=\"%s\", nc=%s%s",
1274 			     hdr, parms->user, c->realm,
1275 			     c->nonce, url->doc, digest,
1276 			     cnonce, noncecount, options);
1277 	} else {
1278 		r = http_cmd(conn, "%s: Digest username=\"%s\",realm=\"%s\","
1279 			     "nonce=\"%s\",uri=\"%s\",response=\"%s\"%s",
1280 			     hdr, parms->user, c->realm,
1281 			     c->nonce, url->doc, digest, options);
1282 	}
1283 	if (options)
1284 		free(options);
1285 	return (r);
1286 }
1287 
1288 /*
1289  * Encode username and password
1290  */
1291 static int
1292 http_basic_auth(conn_t *conn, const char *hdr, const char *usr, const char *pwd)
1293 {
1294 	char *upw, *auth;
1295 	int r;
1296 
1297 	DEBUG(fprintf(stderr, "basic: usr: [%s]\n", usr));
1298 	DEBUG(fprintf(stderr, "basic: pwd: [%s]\n", pwd));
1299 	if (asprintf(&upw, "%s:%s", usr, pwd) == -1)
1300 		return (-1);
1301 	auth = http_base64(upw);
1302 	free(upw);
1303 	if (auth == NULL)
1304 		return (-1);
1305 	r = http_cmd(conn, "%s: Basic %s", hdr, auth);
1306 	free(auth);
1307 	return (r);
1308 }
1309 
1310 /*
1311  * Chose the challenge to answer and call the appropriate routine to
1312  * produce the header.
1313  */
1314 static int
1315 http_authorize(conn_t *conn, const char *hdr, http_auth_challenges_t *cs,
1316 	       http_auth_params_t *parms, struct url *url)
1317 {
1318 	http_auth_challenge_t *basic = NULL;
1319 	http_auth_challenge_t *digest = NULL;
1320 	int i;
1321 
1322 	/* If user or pass are null we're not happy */
1323 	if (!parms->user || !parms->password) {
1324 		DEBUG(fprintf(stderr, "NULL usr or pass\n"));
1325 		return (-1);
1326 	}
1327 
1328 	/* Look for a Digest and a Basic challenge */
1329 	for (i = 0; i < cs->count; i++) {
1330 		if (cs->challenges[i]->scheme == HTTPAS_BASIC)
1331 			basic = cs->challenges[i];
1332 		if (cs->challenges[i]->scheme == HTTPAS_DIGEST)
1333 			digest = cs->challenges[i];
1334 	}
1335 
1336 	/* Error if "Digest" was specified and there is no Digest challenge */
1337 	if (!digest && (parms->scheme &&
1338 			!strcasecmp(parms->scheme, "digest"))) {
1339 		DEBUG(fprintf(stderr,
1340 			      "Digest auth in env, not supported by peer\n"));
1341 		return (-1);
1342 	}
1343 	/*
1344 	 * If "basic" was specified in the environment, or there is no Digest
1345 	 * challenge, do the basic thing. Don't need a challenge for this,
1346 	 * so no need to check basic!=NULL
1347 	 */
1348 	if (!digest || (parms->scheme && !strcasecmp(parms->scheme,"basic")))
1349 		return (http_basic_auth(conn,hdr,parms->user,parms->password));
1350 
1351 	/* Else, prefer digest. We just checked that it's not NULL */
1352 	return (http_digest_auth(conn, hdr, digest, parms, url));
1353 }
1354 
1355 /*****************************************************************************
1356  * Helper functions for connecting to a server or proxy
1357  */
1358 
1359 /*
1360  * Connect to the correct HTTP server or proxy.
1361  */
1362 static conn_t *
1363 http_connect(struct url *URL, struct url *purl, const char *flags)
1364 {
1365 	conn_t *conn;
1366 	int verbose;
1367 	int af, val;
1368 
1369 #ifdef INET6
1370 	af = AF_UNSPEC;
1371 #else
1372 	af = AF_INET;
1373 #endif
1374 
1375 	verbose = CHECK_FLAG('v');
1376 	if (CHECK_FLAG('4'))
1377 		af = AF_INET;
1378 #ifdef INET6
1379 	else if (CHECK_FLAG('6'))
1380 		af = AF_INET6;
1381 #endif
1382 
1383 	if (purl && strcasecmp(URL->scheme, SCHEME_HTTPS) != 0) {
1384 		URL = purl;
1385 	} else if (strcasecmp(URL->scheme, SCHEME_FTP) == 0) {
1386 		/* can't talk http to an ftp server */
1387 		/* XXX should set an error code */
1388 		return (NULL);
1389 	}
1390 
1391 	if ((conn = fetch_connect(URL->host, URL->port, af, verbose)) == NULL)
1392 		/* fetch_connect() has already set an error code */
1393 		return (NULL);
1394 	if (strcasecmp(URL->scheme, SCHEME_HTTPS) == 0 &&
1395 	    fetch_ssl(conn, verbose) == -1) {
1396 		fetch_close(conn);
1397 		/* grrr */
1398 		errno = EAUTH;
1399 		fetch_syserr();
1400 		return (NULL);
1401 	}
1402 
1403 	val = 1;
1404 	setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val, sizeof(val));
1405 
1406 	return (conn);
1407 }
1408 
1409 static struct url *
1410 http_get_proxy(struct url * url, const char *flags)
1411 {
1412 	struct url *purl;
1413 	char *p;
1414 
1415 	if (flags != NULL && strchr(flags, 'd') != NULL)
1416 		return (NULL);
1417 	if (fetch_no_proxy_match(url->host))
1418 		return (NULL);
1419 	if (((p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
1420 	    *p && (purl = fetchParseURL(p))) {
1421 		if (!*purl->scheme)
1422 			strcpy(purl->scheme, SCHEME_HTTP);
1423 		if (!purl->port)
1424 			purl->port = fetch_default_proxy_port(purl->scheme);
1425 		if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
1426 			return (purl);
1427 		fetchFreeURL(purl);
1428 	}
1429 	return (NULL);
1430 }
1431 
1432 static void
1433 http_print_html(FILE *out, FILE *in)
1434 {
1435 	size_t len;
1436 	char *line, *p, *q;
1437 	int comment, tag;
1438 
1439 	comment = tag = 0;
1440 	while ((line = fgetln(in, &len)) != NULL) {
1441 		while (len && isspace((unsigned char)line[len - 1]))
1442 			--len;
1443 		for (p = q = line; q < line + len; ++q) {
1444 			if (comment && *q == '-') {
1445 				if (q + 2 < line + len &&
1446 				    strcmp(q, "-->") == 0) {
1447 					tag = comment = 0;
1448 					q += 2;
1449 				}
1450 			} else if (tag && !comment && *q == '>') {
1451 				p = q + 1;
1452 				tag = 0;
1453 			} else if (!tag && *q == '<') {
1454 				if (q > p)
1455 					fwrite(p, q - p, 1, out);
1456 				tag = 1;
1457 				if (q + 3 < line + len &&
1458 				    strcmp(q, "<!--") == 0) {
1459 					comment = 1;
1460 					q += 3;
1461 				}
1462 			}
1463 		}
1464 		if (!tag && q > p)
1465 			fwrite(p, q - p, 1, out);
1466 		fputc('\n', out);
1467 	}
1468 }
1469 
1470 
1471 /*****************************************************************************
1472  * Core
1473  */
1474 
1475 /*
1476  * Send a request and process the reply
1477  *
1478  * XXX This function is way too long, the do..while loop should be split
1479  * XXX off into a separate function.
1480  */
1481 FILE *
1482 http_request(struct url *URL, const char *op, struct url_stat *us,
1483 	struct url *purl, const char *flags)
1484 {
1485 	char timebuf[80];
1486 	char hbuf[MAXHOSTNAMELEN + 7], *host;
1487 	conn_t *conn;
1488 	struct url *url, *new;
1489 	int chunked, direct, ims, noredirect, verbose;
1490 	int e, i, n, val;
1491 	off_t offset, clength, length, size;
1492 	time_t mtime;
1493 	const char *p;
1494 	FILE *f;
1495 	hdr_t h;
1496 	struct tm *timestruct;
1497 	http_headerbuf_t headerbuf;
1498 	http_auth_challenges_t server_challenges;
1499 	http_auth_challenges_t proxy_challenges;
1500 
1501 	/* The following calls don't allocate anything */
1502 	init_http_headerbuf(&headerbuf);
1503 	init_http_auth_challenges(&server_challenges);
1504 	init_http_auth_challenges(&proxy_challenges);
1505 
1506 	direct = CHECK_FLAG('d');
1507 	noredirect = CHECK_FLAG('A');
1508 	verbose = CHECK_FLAG('v');
1509 	ims = CHECK_FLAG('i');
1510 
1511 	if (direct && purl) {
1512 		fetchFreeURL(purl);
1513 		purl = NULL;
1514 	}
1515 
1516 	/* try the provided URL first */
1517 	url = URL;
1518 
1519 	/* if the A flag is set, we only get one try */
1520 	n = noredirect ? 1 : MAX_REDIRECT;
1521 	i = 0;
1522 
1523 	e = HTTP_PROTOCOL_ERROR;
1524 	do {
1525 		new = NULL;
1526 		chunked = 0;
1527 		offset = 0;
1528 		clength = -1;
1529 		length = -1;
1530 		size = -1;
1531 		mtime = 0;
1532 
1533 		/* check port */
1534 		if (!url->port)
1535 			url->port = fetch_default_port(url->scheme);
1536 
1537 		/* were we redirected to an FTP URL? */
1538 		if (purl == NULL && strcmp(url->scheme, SCHEME_FTP) == 0) {
1539 			if (strcmp(op, "GET") == 0)
1540 				return (ftp_request(url, "RETR", us, purl, flags));
1541 			else if (strcmp(op, "HEAD") == 0)
1542 				return (ftp_request(url, "STAT", us, purl, flags));
1543 		}
1544 
1545 		/* connect to server or proxy */
1546 		if ((conn = http_connect(url, purl, flags)) == NULL)
1547 			goto ouch;
1548 
1549 		host = url->host;
1550 #ifdef INET6
1551 		if (strchr(url->host, ':')) {
1552 			snprintf(hbuf, sizeof(hbuf), "[%s]", url->host);
1553 			host = hbuf;
1554 		}
1555 #endif
1556 		if (url->port != fetch_default_port(url->scheme)) {
1557 			if (host != hbuf) {
1558 				strcpy(hbuf, host);
1559 				host = hbuf;
1560 			}
1561 			snprintf(hbuf + strlen(hbuf),
1562 			    sizeof(hbuf) - strlen(hbuf), ":%d", url->port);
1563 		}
1564 
1565 		/* send request */
1566 		if (verbose)
1567 			fetch_info("requesting %s://%s%s",
1568 			    url->scheme, host, url->doc);
1569 		if (purl) {
1570 			http_cmd(conn, "%s %s://%s%s HTTP/1.1",
1571 			    op, url->scheme, host, url->doc);
1572 		} else {
1573 			http_cmd(conn, "%s %s HTTP/1.1",
1574 			    op, url->doc);
1575 		}
1576 
1577 		if (ims && url->ims_time) {
1578 			timestruct = gmtime((time_t *)&url->ims_time);
1579 			(void)strftime(timebuf, 80, "%a, %d %b %Y %T GMT",
1580 			    timestruct);
1581 			if (verbose)
1582 				fetch_info("If-Modified-Since: %s", timebuf);
1583 			http_cmd(conn, "If-Modified-Since: %s", timebuf);
1584 		}
1585 		/* virtual host */
1586 		http_cmd(conn, "Host: %s", host);
1587 
1588 		/*
1589 		 * Proxy authorization: we only send auth after we received
1590 		 * a 407 error. We do not first try basic anyway (changed
1591 		 * when support was added for digest-auth)
1592 		 */
1593 		if (purl && proxy_challenges.valid) {
1594 			http_auth_params_t aparams;
1595 			init_http_auth_params(&aparams);
1596 			if (*purl->user || *purl->pwd) {
1597 				aparams.user = purl->user ?
1598 					strdup(purl->user) : strdup("");
1599 				aparams.password = purl->pwd?
1600 					strdup(purl->pwd) : strdup("");
1601 			} else if ((p = getenv("HTTP_PROXY_AUTH")) != NULL &&
1602 				   *p != '\0') {
1603 				if (http_authfromenv(p, &aparams) < 0) {
1604 					http_seterr(HTTP_NEED_PROXY_AUTH);
1605 					goto ouch;
1606 				}
1607 			}
1608 			http_authorize(conn, "Proxy-Authorization",
1609 				       &proxy_challenges, &aparams, url);
1610 			clean_http_auth_params(&aparams);
1611 		}
1612 
1613 		/*
1614 		 * Server authorization: we never send "a priori"
1615 		 * Basic auth, which used to be done if user/pass were
1616 		 * set in the url. This would be weird because we'd send the
1617 		 * password in the clear even if Digest is finally to be
1618 		 * used (it would have made more sense for the
1619 		 * pre-digest version to do this when Basic was specified
1620 		 * in the environment)
1621 		 */
1622 		if (server_challenges.valid) {
1623 			http_auth_params_t aparams;
1624 			init_http_auth_params(&aparams);
1625 			if (*url->user || *url->pwd) {
1626 				aparams.user = url->user ?
1627 					strdup(url->user) : strdup("");
1628 				aparams.password = url->pwd ?
1629 					strdup(url->pwd) : strdup("");
1630 			} else if ((p = getenv("HTTP_AUTH")) != NULL &&
1631 				   *p != '\0') {
1632 				if (http_authfromenv(p, &aparams) < 0) {
1633 					http_seterr(HTTP_NEED_AUTH);
1634 					goto ouch;
1635 				}
1636 			} else if (fetchAuthMethod &&
1637 				   fetchAuthMethod(url) == 0) {
1638 				aparams.user = url->user ?
1639 					strdup(url->user) : strdup("");
1640 				aparams.password = url->pwd ?
1641 					strdup(url->pwd) : strdup("");
1642 			} else {
1643 				http_seterr(HTTP_NEED_AUTH);
1644 				goto ouch;
1645 			}
1646 			http_authorize(conn, "Authorization",
1647 				       &server_challenges, &aparams, url);
1648 			clean_http_auth_params(&aparams);
1649 		}
1650 
1651 		/* other headers */
1652 		if ((p = getenv("HTTP_REFERER")) != NULL && *p != '\0') {
1653 			if (strcasecmp(p, "auto") == 0)
1654 				http_cmd(conn, "Referer: %s://%s%s",
1655 				    url->scheme, host, url->doc);
1656 			else
1657 				http_cmd(conn, "Referer: %s", p);
1658 		}
1659 		if ((p = getenv("HTTP_USER_AGENT")) != NULL && *p != '\0')
1660 			http_cmd(conn, "User-Agent: %s", p);
1661 		else
1662 			http_cmd(conn, "User-Agent: %s " _LIBFETCH_VER, getprogname());
1663 		if (url->offset > 0)
1664 			http_cmd(conn, "Range: bytes=%lld-", (long long)url->offset);
1665 		http_cmd(conn, "Connection: close");
1666 		http_cmd(conn, "");
1667 
1668 		/*
1669 		 * Force the queued request to be dispatched.  Normally, one
1670 		 * would do this with shutdown(2) but squid proxies can be
1671 		 * configured to disallow such half-closed connections.  To
1672 		 * be compatible with such configurations, fiddle with socket
1673 		 * options to force the pending data to be written.
1674 		 */
1675 		val = 0;
1676 		setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val,
1677 			   sizeof(val));
1678 		val = 1;
1679 		setsockopt(conn->sd, IPPROTO_TCP, TCP_NODELAY, &val,
1680 			   sizeof(val));
1681 
1682 		/* get reply */
1683 		switch (http_get_reply(conn)) {
1684 		case HTTP_OK:
1685 		case HTTP_PARTIAL:
1686 		case HTTP_NOT_MODIFIED:
1687 			/* fine */
1688 			break;
1689 		case HTTP_MOVED_PERM:
1690 		case HTTP_MOVED_TEMP:
1691 		case HTTP_SEE_OTHER:
1692 			/*
1693 			 * Not so fine, but we still have to read the
1694 			 * headers to get the new location.
1695 			 */
1696 			break;
1697 		case HTTP_NEED_AUTH:
1698 			if (server_challenges.valid) {
1699 				/*
1700 				 * We already sent out authorization code,
1701 				 * so there's nothing more we can do.
1702 				 */
1703 				http_seterr(conn->err);
1704 				goto ouch;
1705 			}
1706 			/* try again, but send the password this time */
1707 			if (verbose)
1708 				fetch_info("server requires authorization");
1709 			break;
1710 		case HTTP_NEED_PROXY_AUTH:
1711 			if (proxy_challenges.valid) {
1712 				/*
1713 				 * We already sent our proxy
1714 				 * authorization code, so there's
1715 				 * nothing more we can do. */
1716 				http_seterr(conn->err);
1717 				goto ouch;
1718 			}
1719 			/* try again, but send the password this time */
1720 			if (verbose)
1721 				fetch_info("proxy requires authorization");
1722 			break;
1723 		case HTTP_BAD_RANGE:
1724 			/*
1725 			 * This can happen if we ask for 0 bytes because
1726 			 * we already have the whole file.  Consider this
1727 			 * a success for now, and check sizes later.
1728 			 */
1729 			break;
1730 		case HTTP_PROTOCOL_ERROR:
1731 			/* fall through */
1732 		case -1:
1733 			fetch_syserr();
1734 			goto ouch;
1735 		default:
1736 			http_seterr(conn->err);
1737 			if (!verbose)
1738 				goto ouch;
1739 			/* fall through so we can get the full error message */
1740 		}
1741 
1742 		/* get headers. http_next_header expects one line readahead */
1743 		if (fetch_getln(conn) == -1) {
1744 		    fetch_syserr();
1745 		    goto ouch;
1746 		}
1747 		do {
1748 		    switch ((h = http_next_header(conn, &headerbuf, &p))) {
1749 			case hdr_syserror:
1750 				fetch_syserr();
1751 				goto ouch;
1752 			case hdr_error:
1753 				http_seterr(HTTP_PROTOCOL_ERROR);
1754 				goto ouch;
1755 			case hdr_content_length:
1756 				http_parse_length(p, &clength);
1757 				break;
1758 			case hdr_content_range:
1759 				http_parse_range(p, &offset, &length, &size);
1760 				break;
1761 			case hdr_last_modified:
1762 				http_parse_mtime(p, &mtime);
1763 				break;
1764 			case hdr_location:
1765 				if (!HTTP_REDIRECT(conn->err))
1766 					break;
1767 				if (new)
1768 					free(new);
1769 				if (verbose)
1770 					fetch_info("%d redirect to %s", conn->err, p);
1771 				if (*p == '/')
1772 					/* absolute path */
1773 					new = fetchMakeURL(url->scheme, url->host, url->port, p,
1774 					    url->user, url->pwd);
1775 				else
1776 					new = fetchParseURL(p);
1777 				if (new == NULL) {
1778 					/* XXX should set an error code */
1779 					DEBUG(fprintf(stderr, "failed to parse new URL\n"));
1780 					goto ouch;
1781 				}
1782 
1783 				/* Only copy credentials if the host matches */
1784 				if (!strcmp(new->host, url->host) && !*new->user && !*new->pwd) {
1785 					strcpy(new->user, url->user);
1786 					strcpy(new->pwd, url->pwd);
1787 				}
1788 				new->offset = url->offset;
1789 				new->length = url->length;
1790 				break;
1791 			case hdr_transfer_encoding:
1792 				/* XXX weak test*/
1793 				chunked = (strcasecmp(p, "chunked") == 0);
1794 				break;
1795 			case hdr_www_authenticate:
1796 				if (conn->err != HTTP_NEED_AUTH)
1797 					break;
1798 				if (http_parse_authenticate(p, &server_challenges) == 0)
1799 					++n;
1800 				break;
1801 			case hdr_proxy_authenticate:
1802 				if (conn->err != HTTP_NEED_PROXY_AUTH)
1803 					break;
1804 				if (http_parse_authenticate(p, &proxy_challenges) == 0)
1805 					++n;
1806 				break;
1807 			case hdr_end:
1808 				/* fall through */
1809 			case hdr_unknown:
1810 				/* ignore */
1811 				break;
1812 			}
1813 		} while (h > hdr_end);
1814 
1815 		/* we need to provide authentication */
1816 		if (conn->err == HTTP_NEED_AUTH ||
1817 		    conn->err == HTTP_NEED_PROXY_AUTH) {
1818 			e = conn->err;
1819 			if ((conn->err == HTTP_NEED_AUTH &&
1820 			     !server_challenges.valid) ||
1821 			    (conn->err == HTTP_NEED_PROXY_AUTH &&
1822 			     !proxy_challenges.valid)) {
1823 				/* 401/7 but no www/proxy-authenticate ?? */
1824 				DEBUG(fprintf(stderr, "401/7 and no auth header\n"));
1825 				goto ouch;
1826 			}
1827 			fetch_close(conn);
1828 			conn = NULL;
1829 			continue;
1830 		}
1831 
1832 		/* requested range not satisfiable */
1833 		if (conn->err == HTTP_BAD_RANGE) {
1834 			if (url->offset == size && url->length == 0) {
1835 				/* asked for 0 bytes; fake it */
1836 				offset = url->offset;
1837 				clength = -1;
1838 				conn->err = HTTP_OK;
1839 				break;
1840 			} else {
1841 				http_seterr(conn->err);
1842 				goto ouch;
1843 			}
1844 		}
1845 
1846 		/* we have a hit or an error */
1847 		if (conn->err == HTTP_OK
1848 		    || conn->err == HTTP_NOT_MODIFIED
1849 		    || conn->err == HTTP_PARTIAL
1850 		    || HTTP_ERROR(conn->err))
1851 			break;
1852 
1853 		/* all other cases: we got a redirect */
1854 		e = conn->err;
1855 		clean_http_auth_challenges(&server_challenges);
1856 		fetch_close(conn);
1857 		conn = NULL;
1858 		if (!new) {
1859 			DEBUG(fprintf(stderr, "redirect with no new location\n"));
1860 			break;
1861 		}
1862 		if (url != URL)
1863 			fetchFreeURL(url);
1864 		url = new;
1865 	} while (++i < n);
1866 
1867 	/* we failed, or ran out of retries */
1868 	if (conn == NULL) {
1869 		http_seterr(e);
1870 		goto ouch;
1871 	}
1872 
1873 	DEBUG(fprintf(stderr, "offset %lld, length %lld,"
1874 		  " size %lld, clength %lld\n",
1875 		  (long long)offset, (long long)length,
1876 		  (long long)size, (long long)clength));
1877 
1878 	if (conn->err == HTTP_NOT_MODIFIED) {
1879 		http_seterr(HTTP_NOT_MODIFIED);
1880 		return (NULL);
1881 	}
1882 
1883 	/* check for inconsistencies */
1884 	if (clength != -1 && length != -1 && clength != length) {
1885 		http_seterr(HTTP_PROTOCOL_ERROR);
1886 		goto ouch;
1887 	}
1888 	if (clength == -1)
1889 		clength = length;
1890 	if (clength != -1)
1891 		length = offset + clength;
1892 	if (length != -1 && size != -1 && length != size) {
1893 		http_seterr(HTTP_PROTOCOL_ERROR);
1894 		goto ouch;
1895 	}
1896 	if (size == -1)
1897 		size = length;
1898 
1899 	/* fill in stats */
1900 	if (us) {
1901 		us->size = size;
1902 		us->atime = us->mtime = mtime;
1903 	}
1904 
1905 	/* too far? */
1906 	if (URL->offset > 0 && offset > URL->offset) {
1907 		http_seterr(HTTP_PROTOCOL_ERROR);
1908 		goto ouch;
1909 	}
1910 
1911 	/* report back real offset and size */
1912 	URL->offset = offset;
1913 	URL->length = clength;
1914 
1915 	/* wrap it up in a FILE */
1916 	if ((f = http_funopen(conn, chunked)) == NULL) {
1917 		fetch_syserr();
1918 		goto ouch;
1919 	}
1920 
1921 	if (url != URL)
1922 		fetchFreeURL(url);
1923 	if (purl)
1924 		fetchFreeURL(purl);
1925 
1926 	if (HTTP_ERROR(conn->err)) {
1927 		http_print_html(stderr, f);
1928 		fclose(f);
1929 		f = NULL;
1930 	}
1931 	clean_http_headerbuf(&headerbuf);
1932 	clean_http_auth_challenges(&server_challenges);
1933 	clean_http_auth_challenges(&proxy_challenges);
1934 	return (f);
1935 
1936 ouch:
1937 	if (url != URL)
1938 		fetchFreeURL(url);
1939 	if (purl)
1940 		fetchFreeURL(purl);
1941 	if (conn != NULL)
1942 		fetch_close(conn);
1943 	clean_http_headerbuf(&headerbuf);
1944 	clean_http_auth_challenges(&server_challenges);
1945 	clean_http_auth_challenges(&proxy_challenges);
1946 	return (NULL);
1947 }
1948 
1949 
1950 /*****************************************************************************
1951  * Entry points
1952  */
1953 
1954 /*
1955  * Retrieve and stat a file by HTTP
1956  */
1957 FILE *
1958 fetchXGetHTTP(struct url *URL, struct url_stat *us, const char *flags)
1959 {
1960 	return (http_request(URL, "GET", us, http_get_proxy(URL, flags), flags));
1961 }
1962 
1963 /*
1964  * Retrieve a file by HTTP
1965  */
1966 FILE *
1967 fetchGetHTTP(struct url *URL, const char *flags)
1968 {
1969 	return (fetchXGetHTTP(URL, NULL, flags));
1970 }
1971 
1972 /*
1973  * Store a file by HTTP
1974  */
1975 FILE *
1976 fetchPutHTTP(struct url *URL __unused, const char *flags __unused)
1977 {
1978 	warnx("fetchPutHTTP(): not implemented");
1979 	return (NULL);
1980 }
1981 
1982 /*
1983  * Get an HTTP document's metadata
1984  */
1985 int
1986 fetchStatHTTP(struct url *URL, struct url_stat *us, const char *flags)
1987 {
1988 	FILE *f;
1989 
1990 	f = http_request(URL, "HEAD", us, http_get_proxy(URL, flags), flags);
1991 	if (f == NULL)
1992 		return (-1);
1993 	fclose(f);
1994 	return (0);
1995 }
1996 
1997 /*
1998  * List a directory
1999  */
2000 struct url_ent *
2001 fetchListHTTP(struct url *url __unused, const char *flags __unused)
2002 {
2003 	warnx("fetchListHTTP(): not implemented");
2004 	return (NULL);
2005 }
2006