http.c revision 125697 
1/*-
2 * Copyright (c) 2000 Dag-Erling Co�dan Sm�rgrav
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer
10 *    in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 *    derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: head/lib/libfetch/http.c 125697 2004-02-11 09:35:27Z des $");
31
32/*
33 * The following copyright applies to the base64 code:
34 *
35 *-
36 * Copyright 1997 Massachusetts Institute of Technology
37 *
38 * Permission to use, copy, modify, and distribute this software and
39 * its documentation for any purpose and without fee is hereby
40 * granted, provided that both the above copyright notice and this
41 * permission notice appear in all copies, that both the above
42 * copyright notice and this permission notice appear in all
43 * supporting documentation, and that the name of M.I.T. not be used
44 * in advertising or publicity pertaining to distribution of the
45 * software without specific, written prior permission.  M.I.T. makes
46 * no representations about the suitability of this software for any
47 * purpose.  It is provided "as is" without express or implied
48 * warranty.
49 *
50 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
51 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
52 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
53 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
54 * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
55 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
56 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
57 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
58 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
59 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
60 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
61 * SUCH DAMAGE.
62 */
63
64#include <sys/param.h>
65#include <sys/socket.h>
66
67#include <ctype.h>
68#include <err.h>
69#include <errno.h>
70#include <locale.h>
71#include <netdb.h>
72#include <stdarg.h>
73#include <stdio.h>
74#include <stdlib.h>
75#include <string.h>
76#include <time.h>
77#include <unistd.h>
78
79#include "fetch.h"
80#include "common.h"
81#include "httperr.h"
82
83/* Maximum number of redirects to follow */
84#define MAX_REDIRECT 5
85
86/* Symbolic names for reply codes we care about */
87#define HTTP_OK			200
88#define HTTP_PARTIAL		206
89#define HTTP_MOVED_PERM		301
90#define HTTP_MOVED_TEMP		302
91#define HTTP_SEE_OTHER		303
92#define HTTP_NEED_AUTH		401
93#define HTTP_NEED_PROXY_AUTH	407
94#define HTTP_BAD_RANGE		416
95#define HTTP_PROTOCOL_ERROR	999
96
97#define HTTP_REDIRECT(xyz) ((xyz) == HTTP_MOVED_PERM \
98			    || (xyz) == HTTP_MOVED_TEMP \
99			    || (xyz) == HTTP_SEE_OTHER)
100
101#define HTTP_ERROR(xyz) ((xyz) > 400 && (xyz) < 599)
102
103
104/*****************************************************************************
105 * I/O functions for decoding chunked streams
106 */
107
108struct httpio
109{
110	conn_t		*conn;		/* connection */
111	int		 chunked;	/* chunked mode */
112	char		*buf;		/* chunk buffer */
113	size_t		 bufsize;	/* size of chunk buffer */
114	ssize_t		 buflen;	/* amount of data currently in buffer */
115	int		 bufpos;	/* current read offset in buffer */
116	int		 eof;		/* end-of-file flag */
117	int		 error;		/* error flag */
118	size_t		 chunksize;	/* remaining size of current chunk */
119#ifndef NDEBUG
120	size_t		 total;
121#endif
122};
123
124/*
125 * Get next chunk header
126 */
127static int
128_http_new_chunk(struct httpio *io)
129{
130	char *p;
131
132	if (_fetch_getln(io->conn) == -1)
133		return (-1);
134
135	if (io->conn->buflen < 2 || !ishexnumber(*io->conn->buf))
136		return (-1);
137
138	for (p = io->conn->buf; *p && !isspace(*p); ++p) {
139		if (*p == ';')
140			break;
141		if (!ishexnumber(*p))
142			return (-1);
143		if (isdigit(*p)) {
144			io->chunksize = io->chunksize * 16 +
145			    *p - '0';
146		} else {
147			io->chunksize = io->chunksize * 16 +
148			    10 + tolower(*p) - 'a';
149		}
150	}
151
152#ifndef NDEBUG
153	if (fetchDebug) {
154		io->total += io->chunksize;
155		if (io->chunksize == 0)
156			fprintf(stderr, "%s(): end of last chunk\n", __func__);
157		else
158			fprintf(stderr, "%s(): new chunk: %lu (%lu)\n",
159			    __func__, (unsigned long)io->chunksize,
160			    (unsigned long)io->total);
161	}
162#endif
163
164	return (io->chunksize);
165}
166
167/*
168 * Grow the input buffer to at least len bytes
169 */
170static inline int
171_http_growbuf(struct httpio *io, size_t len)
172{
173	char *tmp;
174
175	if (io->bufsize >= len)
176		return (0);
177
178	if ((tmp = realloc(io->buf, len)) == NULL)
179		return (-1);
180	io->buf = tmp;
181	io->bufsize = len;
182	return (0);
183}
184
185/*
186 * Fill the input buffer, do chunk decoding on the fly
187 */
188static int
189_http_fillbuf(struct httpio *io, size_t len)
190{
191	if (io->error)
192		return (-1);
193	if (io->eof)
194		return (0);
195
196	if (io->chunked == 0) {
197		if (_http_growbuf(io, len) == -1)
198			return (-1);
199		if ((io->buflen = _fetch_read(io->conn, io->buf, len)) == -1) {
200			io->error = 1;
201			return (-1);
202		}
203		io->bufpos = 0;
204		return (io->buflen);
205	}
206
207	if (io->chunksize == 0) {
208		switch (_http_new_chunk(io)) {
209		case -1:
210			io->error = 1;
211			return (-1);
212		case 0:
213			io->eof = 1;
214			return (0);
215		}
216	}
217
218	if (len > io->chunksize)
219		len = io->chunksize;
220	if (_http_growbuf(io, len) == -1)
221		return (-1);
222	if ((io->buflen = _fetch_read(io->conn, io->buf, len)) == -1) {
223		io->error = 1;
224		return (-1);
225	}
226	io->chunksize -= io->buflen;
227
228	if (io->chunksize == 0) {
229		char endl[2];
230
231		if (_fetch_read(io->conn, endl, 2) != 2 ||
232		    endl[0] != '\r' || endl[1] != '\n')
233			return (-1);
234	}
235
236	io->bufpos = 0;
237
238	return (io->buflen);
239}
240
241/*
242 * Read function
243 */
244static int
245_http_readfn(void *v, char *buf, int len)
246{
247	struct httpio *io = (struct httpio *)v;
248	int l, pos;
249
250	if (io->error)
251		return (-1);
252	if (io->eof)
253		return (0);
254
255	for (pos = 0; len > 0; pos += l, len -= l) {
256		/* empty buffer */
257		if (!io->buf || io->bufpos == io->buflen)
258			if (_http_fillbuf(io, len) < 1)
259				break;
260		l = io->buflen - io->bufpos;
261		if (len < l)
262			l = len;
263		bcopy(io->buf + io->bufpos, buf + pos, l);
264		io->bufpos += l;
265	}
266
267	if (!pos && io->error)
268		return (-1);
269	return (pos);
270}
271
272/*
273 * Write function
274 */
275static int
276_http_writefn(void *v, const char *buf, int len)
277{
278	struct httpio *io = (struct httpio *)v;
279
280	return (_fetch_write(io->conn, buf, len));
281}
282
283/*
284 * Close function
285 */
286static int
287_http_closefn(void *v)
288{
289	struct httpio *io = (struct httpio *)v;
290	int r;
291
292	r = _fetch_close(io->conn);
293	if (io->buf)
294		free(io->buf);
295	free(io);
296	return (r);
297}
298
299/*
300 * Wrap a file descriptor up
301 */
302static FILE *
303_http_funopen(conn_t *conn, int chunked)
304{
305	struct httpio *io;
306	FILE *f;
307
308	if ((io = calloc(1, sizeof(*io))) == NULL) {
309		_fetch_syserr();
310		return (NULL);
311	}
312	io->conn = conn;
313	io->chunked = chunked;
314	f = funopen(io, _http_readfn, _http_writefn, NULL, _http_closefn);
315	if (f == NULL) {
316		_fetch_syserr();
317		free(io);
318		return (NULL);
319	}
320	return (f);
321}
322
323
324/*****************************************************************************
325 * Helper functions for talking to the server and parsing its replies
326 */
327
328/* Header types */
329typedef enum {
330	hdr_syserror = -2,
331	hdr_error = -1,
332	hdr_end = 0,
333	hdr_unknown = 1,
334	hdr_content_length,
335	hdr_content_range,
336	hdr_last_modified,
337	hdr_location,
338	hdr_transfer_encoding,
339	hdr_www_authenticate
340} hdr_t;
341
342/* Names of interesting headers */
343static struct {
344	hdr_t		 num;
345	const char	*name;
346} hdr_names[] = {
347	{ hdr_content_length,		"Content-Length" },
348	{ hdr_content_range,		"Content-Range" },
349	{ hdr_last_modified,		"Last-Modified" },
350	{ hdr_location,			"Location" },
351	{ hdr_transfer_encoding,	"Transfer-Encoding" },
352	{ hdr_www_authenticate,		"WWW-Authenticate" },
353	{ hdr_unknown,			NULL },
354};
355
356/*
357 * Send a formatted line; optionally echo to terminal
358 */
359static int
360_http_cmd(conn_t *conn, const char *fmt, ...)
361{
362	va_list ap;
363	size_t len;
364	char *msg;
365	int r;
366
367	va_start(ap, fmt);
368	len = vasprintf(&msg, fmt, ap);
369	va_end(ap);
370
371	if (msg == NULL) {
372		errno = ENOMEM;
373		_fetch_syserr();
374		return (-1);
375	}
376
377	r = _fetch_putln(conn, msg, len);
378	free(msg);
379
380	if (r == -1) {
381		_fetch_syserr();
382		return (-1);
383	}
384
385	return (0);
386}
387
388/*
389 * Get and parse status line
390 */
391static int
392_http_get_reply(conn_t *conn)
393{
394	char *p;
395
396	if (_fetch_getln(conn) == -1)
397		return (-1);
398	/*
399	 * A valid status line looks like "HTTP/m.n xyz reason" where m
400	 * and n are the major and minor protocol version numbers and xyz
401	 * is the reply code.
402	 * Unfortunately, there are servers out there (NCSA 1.5.1, to name
403	 * just one) that do not send a version number, so we can't rely
404	 * on finding one, but if we do, insist on it being 1.0 or 1.1.
405	 * We don't care about the reason phrase.
406	 */
407	if (strncmp(conn->buf, "HTTP", 4) != 0)
408		return (HTTP_PROTOCOL_ERROR);
409	p = conn->buf + 4;
410	if (*p == '/') {
411		if (p[1] != '1' || p[2] != '.' || (p[3] != '0' && p[3] != '1'))
412			return (HTTP_PROTOCOL_ERROR);
413		p += 4;
414	}
415	if (*p != ' ' || !isdigit(p[1]) || !isdigit(p[2]) || !isdigit(p[3]))
416		return (HTTP_PROTOCOL_ERROR);
417
418	conn->err = (p[1] - '0') * 100 + (p[2] - '0') * 10 + (p[3] - '0');
419	return (conn->err);
420}
421
422/*
423 * Check a header; if the type matches the given string, return a pointer
424 * to the beginning of the value.
425 */
426static const char *
427_http_match(const char *str, const char *hdr)
428{
429	while (*str && *hdr && tolower(*str++) == tolower(*hdr++))
430		/* nothing */;
431	if (*str || *hdr != ':')
432		return (NULL);
433	while (*hdr && isspace(*++hdr))
434		/* nothing */;
435	return (hdr);
436}
437
438/*
439 * Get the next header and return the appropriate symbolic code.
440 */
441static hdr_t
442_http_next_header(conn_t *conn, const char **p)
443{
444	int i;
445
446	if (_fetch_getln(conn) == -1)
447		return (hdr_syserror);
448	while (conn->buflen && isspace(conn->buf[conn->buflen - 1]))
449		conn->buflen--;
450	conn->buf[conn->buflen] = '\0';
451	if (conn->buflen == 0)
452		return (hdr_end);
453	/*
454	 * We could check for malformed headers but we don't really care.
455	 * A valid header starts with a token immediately followed by a
456	 * colon; a token is any sequence of non-control, non-whitespace
457	 * characters except "()<>@,;:\\\"{}".
458	 */
459	for (i = 0; hdr_names[i].num != hdr_unknown; i++)
460		if ((*p = _http_match(hdr_names[i].name, conn->buf)) != NULL)
461			return (hdr_names[i].num);
462	return (hdr_unknown);
463}
464
465/*
466 * Parse a last-modified header
467 */
468static int
469_http_parse_mtime(const char *p, time_t *mtime)
470{
471	char locale[64], *r;
472	struct tm tm;
473
474	strncpy(locale, setlocale(LC_TIME, NULL), sizeof(locale));
475	setlocale(LC_TIME, "C");
476	r = strptime(p, "%a, %d %b %Y %H:%M:%S GMT", &tm);
477	/* XXX should add support for date-2 and date-3 */
478	setlocale(LC_TIME, locale);
479	if (r == NULL)
480		return (-1);
481	DEBUG(fprintf(stderr, "last modified: [%04d-%02d-%02d "
482		  "%02d:%02d:%02d]\n",
483		  tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
484		  tm.tm_hour, tm.tm_min, tm.tm_sec));
485	*mtime = timegm(&tm);
486	return (0);
487}
488
489/*
490 * Parse a content-length header
491 */
492static int
493_http_parse_length(const char *p, off_t *length)
494{
495	off_t len;
496
497	for (len = 0; *p && isdigit(*p); ++p)
498		len = len * 10 + (*p - '0');
499	if (*p)
500		return (-1);
501	DEBUG(fprintf(stderr, "content length: [%lld]\n",
502	    (long long)len));
503	*length = len;
504	return (0);
505}
506
507/*
508 * Parse a content-range header
509 */
510static int
511_http_parse_range(const char *p, off_t *offset, off_t *length, off_t *size)
512{
513	off_t first, last, len;
514
515	if (strncasecmp(p, "bytes ", 6) != 0)
516		return (-1);
517	p += 6;
518	if (*p == '*') {
519		first = last = -1;
520		++p;
521	} else {
522		for (first = 0; *p && isdigit(*p); ++p)
523			first = first * 10 + *p - '0';
524		if (*p != '-')
525			return (-1);
526		for (last = 0, ++p; *p && isdigit(*p); ++p)
527			last = last * 10 + *p - '0';
528	}
529	if (first > last || *p != '/')
530		return (-1);
531	for (len = 0, ++p; *p && isdigit(*p); ++p)
532		len = len * 10 + *p - '0';
533	if (*p || len < last - first + 1)
534		return (-1);
535	if (first == -1) {
536		DEBUG(fprintf(stderr, "content range: [*/%lld]\n",
537		    (long long)len));
538		*length = 0;
539	} else {
540		DEBUG(fprintf(stderr, "content range: [%lld-%lld/%lld]\n",
541		    (long long)first, (long long)last, (long long)len));
542		*length = last - first + 1;
543	}
544	*offset = first;
545	*size = len;
546	return (0);
547}
548
549
550/*****************************************************************************
551 * Helper functions for authorization
552 */
553
554/*
555 * Base64 encoding
556 */
557static char *
558_http_base64(const char *src)
559{
560	static const char base64[] =
561	    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
562	    "abcdefghijklmnopqrstuvwxyz"
563	    "0123456789+/";
564	char *str, *dst;
565	size_t l;
566	int t, r;
567
568	l = strlen(src);
569	if ((str = malloc(((l + 2) / 3) * 4)) == NULL)
570		return (NULL);
571	dst = str;
572	r = 0;
573
574	while (l >= 3) {
575		t = (src[0] << 16) | (src[1] << 8) | src[2];
576		dst[0] = base64[(t >> 18) & 0x3f];
577		dst[1] = base64[(t >> 12) & 0x3f];
578		dst[2] = base64[(t >> 6) & 0x3f];
579		dst[3] = base64[(t >> 0) & 0x3f];
580		src += 3; l -= 3;
581		dst += 4; r += 4;
582	}
583
584	switch (l) {
585	case 2:
586		t = (src[0] << 16) | (src[1] << 8);
587		dst[0] = base64[(t >> 18) & 0x3f];
588		dst[1] = base64[(t >> 12) & 0x3f];
589		dst[2] = base64[(t >> 6) & 0x3f];
590		dst[3] = '=';
591		dst += 4;
592		r += 4;
593		break;
594	case 1:
595		t = src[0] << 16;
596		dst[0] = base64[(t >> 18) & 0x3f];
597		dst[1] = base64[(t >> 12) & 0x3f];
598		dst[2] = dst[3] = '=';
599		dst += 4;
600		r += 4;
601		break;
602	case 0:
603		break;
604	}
605
606	*dst = 0;
607	return (str);
608}
609
610/*
611 * Encode username and password
612 */
613static int
614_http_basic_auth(conn_t *conn, const char *hdr, const char *usr, const char *pwd)
615{
616	char *upw, *auth;
617	int r;
618
619	DEBUG(fprintf(stderr, "usr: [%s]\n", usr));
620	DEBUG(fprintf(stderr, "pwd: [%s]\n", pwd));
621	if (asprintf(&upw, "%s:%s", usr, pwd) == -1)
622		return (-1);
623	auth = _http_base64(upw);
624	free(upw);
625	if (auth == NULL)
626		return (-1);
627	r = _http_cmd(conn, "%s: Basic %s", hdr, auth);
628	free(auth);
629	return (r);
630}
631
632/*
633 * Send an authorization header
634 */
635static int
636_http_authorize(conn_t *conn, const char *hdr, const char *p)
637{
638	/* basic authorization */
639	if (strncasecmp(p, "basic:", 6) == 0) {
640		char *user, *pwd, *str;
641		int r;
642
643		/* skip realm */
644		for (p += 6; *p && *p != ':'; ++p)
645			/* nothing */ ;
646		if (!*p || strchr(++p, ':') == NULL)
647			return (-1);
648		if ((str = strdup(p)) == NULL)
649			return (-1); /* XXX */
650		user = str;
651		pwd = strchr(str, ':');
652		*pwd++ = '\0';
653		r = _http_basic_auth(conn, hdr, user, pwd);
654		free(str);
655		return (r);
656	}
657	return (-1);
658}
659
660
661/*****************************************************************************
662 * Helper functions for connecting to a server or proxy
663 */
664
665/*
666 * Connect to the correct HTTP server or proxy.
667 */
668static conn_t *
669_http_connect(struct url *URL, struct url *purl, const char *flags)
670{
671	conn_t *conn;
672	int verbose;
673	int af;
674
675#ifdef INET6
676	af = AF_UNSPEC;
677#else
678	af = AF_INET;
679#endif
680
681	verbose = CHECK_FLAG('v');
682	if (CHECK_FLAG('4'))
683		af = AF_INET;
684#ifdef INET6
685	else if (CHECK_FLAG('6'))
686		af = AF_INET6;
687#endif
688
689	if (purl && strcasecmp(URL->scheme, SCHEME_HTTPS) != 0) {
690		URL = purl;
691	} else if (strcasecmp(URL->scheme, SCHEME_FTP) == 0) {
692		/* can't talk http to an ftp server */
693		/* XXX should set an error code */
694		return (NULL);
695	}
696
697	if ((conn = _fetch_connect(URL->host, URL->port, af, verbose)) == NULL)
698		/* _fetch_connect() has already set an error code */
699		return (NULL);
700	if (strcasecmp(URL->scheme, SCHEME_HTTPS) == 0 &&
701	    _fetch_ssl(conn, verbose) == -1) {
702		_fetch_close(conn);
703		/* grrr */
704		errno = EAUTH;
705		_fetch_syserr();
706		return (NULL);
707	}
708	return (conn);
709}
710
711static struct url *
712_http_get_proxy(const char *flags)
713{
714	struct url *purl;
715	char *p;
716
717	if (flags != NULL && strchr(flags, 'd') != NULL)
718		return (NULL);
719	if (((p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
720	    (purl = fetchParseURL(p))) {
721		if (!*purl->scheme)
722			strcpy(purl->scheme, SCHEME_HTTP);
723		if (!purl->port)
724			purl->port = _fetch_default_proxy_port(purl->scheme);
725		if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
726			return (purl);
727		fetchFreeURL(purl);
728	}
729	return (NULL);
730}
731
732static void
733_http_print_html(FILE *out, FILE *in)
734{
735	size_t len;
736	char *line, *p, *q;
737	int comment, tag;
738
739	comment = tag = 0;
740	while ((line = fgetln(in, &len)) != NULL) {
741		while (len && isspace(line[len - 1]))
742			--len;
743		for (p = q = line; q < line + len; ++q) {
744			if (comment && *q == '-') {
745				if (q + 2 < line + len &&
746				    strcmp(q, "-->") == 0) {
747					tag = comment = 0;
748					q += 2;
749				}
750			} else if (tag && !comment && *q == '>') {
751				p = q + 1;
752				tag = 0;
753			} else if (!tag && *q == '<') {
754				if (q > p)
755					fwrite(p, q - p, 1, out);
756				tag = 1;
757				if (q + 3 < line + len &&
758				    strcmp(q, "<!--") == 0) {
759					comment = 1;
760					q += 3;
761				}
762			}
763		}
764		if (!tag && q > p)
765			fwrite(p, q - p, 1, out);
766		fputc('\n', out);
767	}
768}
769
770
771/*****************************************************************************
772 * Core
773 */
774
775/*
776 * Send a request and process the reply
777 *
778 * XXX This function is way too long, the do..while loop should be split
779 * XXX off into a separate function.
780 */
781FILE *
782_http_request(struct url *URL, const char *op, struct url_stat *us,
783    struct url *purl, const char *flags)
784{
785	conn_t *conn;
786	struct url *url, *new;
787	int chunked, direct, need_auth, noredirect, verbose;
788	int e, i, n;
789	off_t offset, clength, length, size;
790	time_t mtime;
791	const char *p;
792	FILE *f;
793	hdr_t h;
794	char hbuf[MAXHOSTNAMELEN + 7], *host;
795
796	direct = CHECK_FLAG('d');
797	noredirect = CHECK_FLAG('A');
798	verbose = CHECK_FLAG('v');
799
800	if (direct && purl) {
801		fetchFreeURL(purl);
802		purl = NULL;
803	}
804
805	/* try the provided URL first */
806	url = URL;
807
808	/* if the A flag is set, we only get one try */
809	n = noredirect ? 1 : MAX_REDIRECT;
810	i = 0;
811
812	e = HTTP_PROTOCOL_ERROR;
813	need_auth = 0;
814	do {
815		new = NULL;
816		chunked = 0;
817		offset = 0;
818		clength = -1;
819		length = -1;
820		size = -1;
821		mtime = 0;
822
823		/* check port */
824		if (!url->port)
825			url->port = _fetch_default_port(url->scheme);
826
827		/* were we redirected to an FTP URL? */
828		if (purl == NULL && strcmp(url->scheme, SCHEME_FTP) == 0) {
829			if (strcmp(op, "GET") == 0)
830				return (_ftp_request(url, "RETR", us, purl, flags));
831			else if (strcmp(op, "HEAD") == 0)
832				return (_ftp_request(url, "STAT", us, purl, flags));
833		}
834
835		/* connect to server or proxy */
836		if ((conn = _http_connect(url, purl, flags)) == NULL)
837			goto ouch;
838
839		host = url->host;
840#ifdef INET6
841		if (strchr(url->host, ':')) {
842			snprintf(hbuf, sizeof(hbuf), "[%s]", url->host);
843			host = hbuf;
844		}
845#endif
846		if (url->port != _fetch_default_port(url->scheme)) {
847			if (host != hbuf) {
848				strcpy(hbuf, host);
849				host = hbuf;
850			}
851			snprintf(hbuf + strlen(hbuf),
852			    sizeof(hbuf) - strlen(hbuf), ":%d", url->port);
853		}
854
855		/* send request */
856		if (verbose)
857			_fetch_info("requesting %s://%s%s",
858			    url->scheme, host, url->doc);
859		if (purl) {
860			_http_cmd(conn, "%s %s://%s%s HTTP/1.1",
861			    op, url->scheme, host, url->doc);
862		} else {
863			_http_cmd(conn, "%s %s HTTP/1.1",
864			    op, url->doc);
865		}
866
867		/* virtual host */
868		_http_cmd(conn, "Host: %s", host);
869
870		/* proxy authorization */
871		if (purl) {
872			if (*purl->user || *purl->pwd)
873				_http_basic_auth(conn, "Proxy-Authorization",
874				    purl->user, purl->pwd);
875			else if ((p = getenv("HTTP_PROXY_AUTH")) != NULL && *p != '\0')
876				_http_authorize(conn, "Proxy-Authorization", p);
877		}
878
879		/* server authorization */
880		if (need_auth || *url->user || *url->pwd) {
881			if (*url->user || *url->pwd)
882				_http_basic_auth(conn, "Authorization", url->user, url->pwd);
883			else if ((p = getenv("HTTP_AUTH")) != NULL && *p != '\0')
884				_http_authorize(conn, "Authorization", p);
885			else if (fetchAuthMethod && fetchAuthMethod(url) == 0) {
886				_http_basic_auth(conn, "Authorization", url->user, url->pwd);
887			} else {
888				_http_seterr(HTTP_NEED_AUTH);
889				goto ouch;
890			}
891		}
892
893		/* other headers */
894		if ((p = getenv("HTTP_REFERER")) != NULL && *p != '\0') {
895			if (strcasecmp(p, "auto") == 0)
896				_http_cmd(conn, "Referer: %s://%s%s",
897				    url->scheme, host, url->doc);
898			else
899				_http_cmd(conn, "Referer: %s", p);
900		}
901		if ((p = getenv("HTTP_USER_AGENT")) != NULL && *p != '\0')
902			_http_cmd(conn, "User-Agent: %s", p);
903		else
904			_http_cmd(conn, "User-Agent: %s " _LIBFETCH_VER, getprogname());
905		if (url->offset > 0)
906			_http_cmd(conn, "Range: bytes=%lld-", (long long)url->offset);
907		_http_cmd(conn, "Connection: close");
908		_http_cmd(conn, "");
909
910		/* get reply */
911		switch (_http_get_reply(conn)) {
912		case HTTP_OK:
913		case HTTP_PARTIAL:
914			/* fine */
915			break;
916		case HTTP_MOVED_PERM:
917		case HTTP_MOVED_TEMP:
918		case HTTP_SEE_OTHER:
919			/*
920			 * Not so fine, but we still have to read the
921			 * headers to get the new location.
922			 */
923			break;
924		case HTTP_NEED_AUTH:
925			if (need_auth) {
926				/*
927				 * We already sent out authorization code,
928				 * so there's nothing more we can do.
929				 */
930				_http_seterr(conn->err);
931				goto ouch;
932			}
933			/* try again, but send the password this time */
934			if (verbose)
935				_fetch_info("server requires authorization");
936			break;
937		case HTTP_NEED_PROXY_AUTH:
938			/*
939			 * If we're talking to a proxy, we already sent
940			 * our proxy authorization code, so there's
941			 * nothing more we can do.
942			 */
943			_http_seterr(conn->err);
944			goto ouch;
945		case HTTP_BAD_RANGE:
946			/*
947			 * This can happen if we ask for 0 bytes because
948			 * we already have the whole file.  Consider this
949			 * a success for now, and check sizes later.
950			 */
951			break;
952		case HTTP_PROTOCOL_ERROR:
953			/* fall through */
954		case -1:
955			_fetch_syserr();
956			goto ouch;
957		default:
958			_http_seterr(conn->err);
959			if (!verbose)
960				goto ouch;
961			/* fall through so we can get the full error message */
962		}
963
964		/* get headers */
965		do {
966			switch ((h = _http_next_header(conn, &p))) {
967			case hdr_syserror:
968				_fetch_syserr();
969				goto ouch;
970			case hdr_error:
971				_http_seterr(HTTP_PROTOCOL_ERROR);
972				goto ouch;
973			case hdr_content_length:
974				_http_parse_length(p, &clength);
975				break;
976			case hdr_content_range:
977				_http_parse_range(p, &offset, &length, &size);
978				break;
979			case hdr_last_modified:
980				_http_parse_mtime(p, &mtime);
981				break;
982			case hdr_location:
983				if (!HTTP_REDIRECT(conn->err))
984					break;
985				if (new)
986					free(new);
987				if (verbose)
988					_fetch_info("%d redirect to %s", conn->err, p);
989				if (*p == '/')
990					/* absolute path */
991					new = fetchMakeURL(url->scheme, url->host, url->port, p,
992					    url->user, url->pwd);
993				else
994					new = fetchParseURL(p);
995				if (new == NULL) {
996					/* XXX should set an error code */
997					DEBUG(fprintf(stderr, "failed to parse new URL\n"));
998					goto ouch;
999				}
1000				if (!*new->user && !*new->pwd) {
1001					strcpy(new->user, url->user);
1002					strcpy(new->pwd, url->pwd);
1003				}
1004				new->offset = url->offset;
1005				new->length = url->length;
1006				break;
1007			case hdr_transfer_encoding:
1008				/* XXX weak test*/
1009				chunked = (strcasecmp(p, "chunked") == 0);
1010				break;
1011			case hdr_www_authenticate:
1012				if (conn->err != HTTP_NEED_AUTH)
1013					break;
1014				/* if we were smarter, we'd check the method and realm */
1015				break;
1016			case hdr_end:
1017				/* fall through */
1018			case hdr_unknown:
1019				/* ignore */
1020				break;
1021			}
1022		} while (h > hdr_end);
1023
1024		/* we need to provide authentication */
1025		if (conn->err == HTTP_NEED_AUTH) {
1026			e = conn->err;
1027			need_auth = 1;
1028			_fetch_close(conn);
1029			conn = NULL;
1030			continue;
1031		}
1032
1033		/* requested range not satisfiable */
1034		if (conn->err == HTTP_BAD_RANGE) {
1035			if (url->offset == size && url->length == 0) {
1036				/* asked for 0 bytes; fake it */
1037				offset = url->offset;
1038				conn->err = HTTP_OK;
1039				break;
1040			} else {
1041				_http_seterr(conn->err);
1042				goto ouch;
1043			}
1044		}
1045
1046		/* we have a hit or an error */
1047		if (conn->err == HTTP_OK || conn->err == HTTP_PARTIAL || HTTP_ERROR(conn->err))
1048			break;
1049
1050		/* all other cases: we got a redirect */
1051		e = conn->err;
1052		need_auth = 0;
1053		_fetch_close(conn);
1054		conn = NULL;
1055		if (!new) {
1056			DEBUG(fprintf(stderr, "redirect with no new location\n"));
1057			break;
1058		}
1059		if (url != URL)
1060			fetchFreeURL(url);
1061		url = new;
1062	} while (++i < n);
1063
1064	/* we failed, or ran out of retries */
1065	if (conn == NULL) {
1066		_http_seterr(e);
1067		goto ouch;
1068	}
1069
1070	DEBUG(fprintf(stderr, "offset %lld, length %lld,"
1071		  " size %lld, clength %lld\n",
1072		  (long long)offset, (long long)length,
1073		  (long long)size, (long long)clength));
1074
1075	/* check for inconsistencies */
1076	if (clength != -1 && length != -1 && clength != length) {
1077		_http_seterr(HTTP_PROTOCOL_ERROR);
1078		goto ouch;
1079	}
1080	if (clength == -1)
1081		clength = length;
1082	if (clength != -1)
1083		length = offset + clength;
1084	if (length != -1 && size != -1 && length != size) {
1085		_http_seterr(HTTP_PROTOCOL_ERROR);
1086		goto ouch;
1087	}
1088	if (size == -1)
1089		size = length;
1090
1091	/* fill in stats */
1092	if (us) {
1093		us->size = size;
1094		us->atime = us->mtime = mtime;
1095	}
1096
1097	/* too far? */
1098	if (URL->offset > 0 && offset > URL->offset) {
1099		_http_seterr(HTTP_PROTOCOL_ERROR);
1100		goto ouch;
1101	}
1102
1103	/* report back real offset and size */
1104	URL->offset = offset;
1105	URL->length = clength;
1106
1107	/* wrap it up in a FILE */
1108	if ((f = _http_funopen(conn, chunked)) == NULL) {
1109		_fetch_syserr();
1110		goto ouch;
1111	}
1112
1113	if (url != URL)
1114		fetchFreeURL(url);
1115	if (purl)
1116		fetchFreeURL(purl);
1117
1118	if (HTTP_ERROR(conn->err)) {
1119		_http_print_html(stderr, f);
1120		fclose(f);
1121		f = NULL;
1122	}
1123
1124	return (f);
1125
1126ouch:
1127	if (url != URL)
1128		fetchFreeURL(url);
1129	if (purl)
1130		fetchFreeURL(purl);
1131	if (conn != NULL)
1132		_fetch_close(conn);
1133	return (NULL);
1134}
1135
1136
1137/*****************************************************************************
1138 * Entry points
1139 */
1140
1141/*
1142 * Retrieve and stat a file by HTTP
1143 */
1144FILE *
1145fetchXGetHTTP(struct url *URL, struct url_stat *us, const char *flags)
1146{
1147	return (_http_request(URL, "GET", us, _http_get_proxy(flags), flags));
1148}
1149
1150/*
1151 * Retrieve a file by HTTP
1152 */
1153FILE *
1154fetchGetHTTP(struct url *URL, const char *flags)
1155{
1156	return (fetchXGetHTTP(URL, NULL, flags));
1157}
1158
1159/*
1160 * Store a file by HTTP
1161 */
1162FILE *
1163fetchPutHTTP(struct url *URL __unused, const char *flags __unused)
1164{
1165	warnx("fetchPutHTTP(): not implemented");
1166	return (NULL);
1167}
1168
1169/*
1170 * Get an HTTP document's metadata
1171 */
1172int
1173fetchStatHTTP(struct url *URL, struct url_stat *us, const char *flags)
1174{
1175	FILE *f;
1176
1177	f = _http_request(URL, "HEAD", us, _http_get_proxy(flags), flags);
1178	if (f == NULL)
1179		return (-1);
1180	fclose(f);
1181	return (0);
1182}
1183
1184/*
1185 * List a directory
1186 */
1187struct url_ent *
1188fetchListHTTP(struct url *url __unused, const char *flags __unused)
1189{
1190	warnx("fetchListHTTP(): not implemented");
1191	return (NULL);
1192}
1193