http.c revision 174751 
1/*-
2 * Copyright (c) 2000-2004 Dag-Erling Co�dan Sm�rgrav
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer
10 *    in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 *    derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: head/lib/libfetch/http.c 174751 2007-12-18 10:41:12Z 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 <netinet/in.h>
80#include <netinet/tcp.h>
81
82#include "fetch.h"
83#include "common.h"
84#include "httperr.h"
85
86/* Maximum number of redirects to follow */
87#define MAX_REDIRECT 5
88
89/* Symbolic names for reply codes we care about */
90#define HTTP_OK			200
91#define HTTP_PARTIAL		206
92#define HTTP_MOVED_PERM		301
93#define HTTP_MOVED_TEMP		302
94#define HTTP_SEE_OTHER		303
95#define HTTP_TEMP_REDIRECT	307
96#define HTTP_NEED_AUTH		401
97#define HTTP_NEED_PROXY_AUTH	407
98#define HTTP_BAD_RANGE		416
99#define HTTP_PROTOCOL_ERROR	999
100
101#define HTTP_REDIRECT(xyz) ((xyz) == HTTP_MOVED_PERM \
102			    || (xyz) == HTTP_MOVED_TEMP \
103			    || (xyz) == HTTP_TEMP_REDIRECT \
104			    || (xyz) == HTTP_SEE_OTHER)
105
106#define HTTP_ERROR(xyz) ((xyz) > 400 && (xyz) < 599)
107
108
109/*****************************************************************************
110 * I/O functions for decoding chunked streams
111 */
112
113struct httpio
114{
115	conn_t		*conn;		/* connection */
116	int		 chunked;	/* chunked mode */
117	char		*buf;		/* chunk buffer */
118	size_t		 bufsize;	/* size of chunk buffer */
119	ssize_t		 buflen;	/* amount of data currently in buffer */
120	int		 bufpos;	/* current read offset in buffer */
121	int		 eof;		/* end-of-file flag */
122	int		 error;		/* error flag */
123	size_t		 chunksize;	/* remaining size of current chunk */
124#ifndef NDEBUG
125	size_t		 total;
126#endif
127};
128
129/*
130 * Get next chunk header
131 */
132static int
133http_new_chunk(struct httpio *io)
134{
135	char *p;
136
137	if (fetch_getln(io->conn) == -1)
138		return (-1);
139
140	if (io->conn->buflen < 2 || !isxdigit((int)*io->conn->buf))
141		return (-1);
142
143	for (p = io->conn->buf; *p && !isspace((int)*p); ++p) {
144		if (*p == ';')
145			break;
146		if (!isxdigit((int)*p))
147			return (-1);
148		if (isdigit((int)*p)) {
149			io->chunksize = io->chunksize * 16 +
150			    *p - '0';
151		} else {
152			io->chunksize = io->chunksize * 16 +
153			    10 + tolower(*p) - 'a';
154		}
155	}
156
157#ifndef NDEBUG
158	if (fetchDebug) {
159		io->total += io->chunksize;
160		if (io->chunksize == 0)
161			fprintf(stderr, "%s(): end of last chunk\n", __func__);
162		else
163			fprintf(stderr, "%s(): new chunk: %lu (%lu)\n",
164			    __func__, (unsigned long)io->chunksize,
165			    (unsigned long)io->total);
166	}
167#endif
168
169	return (io->chunksize);
170}
171
172/*
173 * Grow the input buffer to at least len bytes
174 */
175static inline int
176http_growbuf(struct httpio *io, size_t len)
177{
178	char *tmp;
179
180	if (io->bufsize >= len)
181		return (0);
182
183	if ((tmp = realloc(io->buf, len)) == NULL)
184		return (-1);
185	io->buf = tmp;
186	io->bufsize = len;
187	return (0);
188}
189
190/*
191 * Fill the input buffer, do chunk decoding on the fly
192 */
193static int
194http_fillbuf(struct httpio *io, size_t len)
195{
196	if (io->error)
197		return (-1);
198	if (io->eof)
199		return (0);
200
201	if (io->chunked == 0) {
202		if (http_growbuf(io, len) == -1)
203			return (-1);
204		if ((io->buflen = fetch_read(io->conn, io->buf, len)) == -1) {
205			io->error = 1;
206			return (-1);
207		}
208		io->bufpos = 0;
209		return (io->buflen);
210	}
211
212	if (io->chunksize == 0) {
213		switch (http_new_chunk(io)) {
214		case -1:
215			io->error = 1;
216			return (-1);
217		case 0:
218			io->eof = 1;
219			return (0);
220		}
221	}
222
223	if (len > io->chunksize)
224		len = io->chunksize;
225	if (http_growbuf(io, len) == -1)
226		return (-1);
227	if ((io->buflen = fetch_read(io->conn, io->buf, len)) == -1) {
228		io->error = 1;
229		return (-1);
230	}
231	io->chunksize -= io->buflen;
232
233	if (io->chunksize == 0) {
234		char endl[2];
235
236		if (fetch_read(io->conn, endl, 2) != 2 ||
237		    endl[0] != '\r' || endl[1] != '\n')
238			return (-1);
239	}
240
241	io->bufpos = 0;
242
243	return (io->buflen);
244}
245
246/*
247 * Read function
248 */
249static int
250http_readfn(void *v, char *buf, int len)
251{
252	struct httpio *io = (struct httpio *)v;
253	int l, pos;
254
255	if (io->error)
256		return (-1);
257	if (io->eof)
258		return (0);
259
260	for (pos = 0; len > 0; pos += l, len -= l) {
261		/* empty buffer */
262		if (!io->buf || io->bufpos == io->buflen)
263			if (http_fillbuf(io, len) < 1)
264				break;
265		l = io->buflen - io->bufpos;
266		if (len < l)
267			l = len;
268		bcopy(io->buf + io->bufpos, buf + pos, l);
269		io->bufpos += l;
270	}
271
272	if (!pos && io->error)
273		return (-1);
274	return (pos);
275}
276
277/*
278 * Write function
279 */
280static int
281http_writefn(void *v, const char *buf, int len)
282{
283	struct httpio *io = (struct httpio *)v;
284
285	return (fetch_write(io->conn, buf, len));
286}
287
288/*
289 * Close function
290 */
291static int
292http_closefn(void *v)
293{
294	struct httpio *io = (struct httpio *)v;
295	int r;
296
297	r = fetch_close(io->conn);
298	if (io->buf)
299		free(io->buf);
300	free(io);
301	return (r);
302}
303
304/*
305 * Wrap a file descriptor up
306 */
307static FILE *
308http_funopen(conn_t *conn, int chunked)
309{
310	struct httpio *io;
311	FILE *f;
312
313	if ((io = calloc(1, sizeof(*io))) == NULL) {
314		fetch_syserr();
315		return (NULL);
316	}
317	io->conn = conn;
318	io->chunked = chunked;
319	f = funopen(io, http_readfn, http_writefn, NULL, http_closefn);
320	if (f == NULL) {
321		fetch_syserr();
322		free(io);
323		return (NULL);
324	}
325	return (f);
326}
327
328
329/*****************************************************************************
330 * Helper functions for talking to the server and parsing its replies
331 */
332
333/* Header types */
334typedef enum {
335	hdr_syserror = -2,
336	hdr_error = -1,
337	hdr_end = 0,
338	hdr_unknown = 1,
339	hdr_content_length,
340	hdr_content_range,
341	hdr_last_modified,
342	hdr_location,
343	hdr_transfer_encoding,
344	hdr_www_authenticate
345} hdr_t;
346
347/* Names of interesting headers */
348static struct {
349	hdr_t		 num;
350	const char	*name;
351} hdr_names[] = {
352	{ hdr_content_length,		"Content-Length" },
353	{ hdr_content_range,		"Content-Range" },
354	{ hdr_last_modified,		"Last-Modified" },
355	{ hdr_location,			"Location" },
356	{ hdr_transfer_encoding,	"Transfer-Encoding" },
357	{ hdr_www_authenticate,		"WWW-Authenticate" },
358	{ hdr_unknown,			NULL },
359};
360
361/*
362 * Send a formatted line; optionally echo to terminal
363 */
364static int
365http_cmd(conn_t *conn, const char *fmt, ...)
366{
367	va_list ap;
368	size_t len;
369	char *msg;
370	int r;
371
372	va_start(ap, fmt);
373	len = vasprintf(&msg, fmt, ap);
374	va_end(ap);
375
376	if (msg == NULL) {
377		errno = ENOMEM;
378		fetch_syserr();
379		return (-1);
380	}
381
382	r = fetch_putln(conn, msg, len);
383	free(msg);
384
385	if (r == -1) {
386		fetch_syserr();
387		return (-1);
388	}
389
390	return (0);
391}
392
393/*
394 * Get and parse status line
395 */
396static int
397http_get_reply(conn_t *conn)
398{
399	char *p;
400
401	if (fetch_getln(conn) == -1)
402		return (-1);
403	/*
404	 * A valid status line looks like "HTTP/m.n xyz reason" where m
405	 * and n are the major and minor protocol version numbers and xyz
406	 * is the reply code.
407	 * Unfortunately, there are servers out there (NCSA 1.5.1, to name
408	 * just one) that do not send a version number, so we can't rely
409	 * on finding one, but if we do, insist on it being 1.0 or 1.1.
410	 * We don't care about the reason phrase.
411	 */
412	if (strncmp(conn->buf, "HTTP", 4) != 0)
413		return (HTTP_PROTOCOL_ERROR);
414	p = conn->buf + 4;
415	if (*p == '/') {
416		if (p[1] != '1' || p[2] != '.' || (p[3] != '0' && p[3] != '1'))
417			return (HTTP_PROTOCOL_ERROR);
418		p += 4;
419	}
420	if (*p != ' ' || !isdigit((int)p[1]) ||
421	    !isdigit((int)p[2]) || !isdigit((int)p[3]))
422		return (HTTP_PROTOCOL_ERROR);
423
424	conn->err = (p[1] - '0') * 100 + (p[2] - '0') * 10 + (p[3] - '0');
425	return (conn->err);
426}
427
428/*
429 * Check a header; if the type matches the given string, return a pointer
430 * to the beginning of the value.
431 */
432static const char *
433http_match(const char *str, const char *hdr)
434{
435	while (*str && *hdr && tolower(*str++) == tolower(*hdr++))
436		/* nothing */;
437	if (*str || *hdr != ':')
438		return (NULL);
439	while (*hdr && isspace((int)*++hdr))
440		/* nothing */;
441	return (hdr);
442}
443
444/*
445 * Get the next header and return the appropriate symbolic code.
446 */
447static hdr_t
448http_next_header(conn_t *conn, const char **p)
449{
450	int i;
451
452	if (fetch_getln(conn) == -1)
453		return (hdr_syserror);
454	while (conn->buflen && isspace((int)conn->buf[conn->buflen - 1]))
455		conn->buflen--;
456	conn->buf[conn->buflen] = '\0';
457	if (conn->buflen == 0)
458		return (hdr_end);
459	/*
460	 * We could check for malformed headers but we don't really care.
461	 * A valid header starts with a token immediately followed by a
462	 * colon; a token is any sequence of non-control, non-whitespace
463	 * characters except "()<>@,;:\\\"{}".
464	 */
465	for (i = 0; hdr_names[i].num != hdr_unknown; i++)
466		if ((*p = http_match(hdr_names[i].name, conn->buf)) != NULL)
467			return (hdr_names[i].num);
468	return (hdr_unknown);
469}
470
471/*
472 * Parse a last-modified header
473 */
474static int
475http_parse_mtime(const char *p, time_t *mtime)
476{
477	char locale[64], *r;
478	struct tm tm;
479
480	strncpy(locale, setlocale(LC_TIME, NULL), sizeof(locale));
481	setlocale(LC_TIME, "C");
482	r = strptime(p, "%a, %d %b %Y %H:%M:%S GMT", &tm);
483	/* XXX should add support for date-2 and date-3 */
484	setlocale(LC_TIME, locale);
485	if (r == NULL)
486		return (-1);
487	DEBUG(fprintf(stderr, "last modified: [%04d-%02d-%02d "
488		  "%02d:%02d:%02d]\n",
489		  tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
490		  tm.tm_hour, tm.tm_min, tm.tm_sec));
491	*mtime = timegm(&tm);
492	return (0);
493}
494
495/*
496 * Parse a content-length header
497 */
498static int
499http_parse_length(const char *p, off_t *length)
500{
501	off_t len;
502
503	for (len = 0; *p && isdigit((int)*p); ++p)
504		len = len * 10 + (*p - '0');
505	if (*p)
506		return (-1);
507	DEBUG(fprintf(stderr, "content length: [%lld]\n",
508	    (long long)len));
509	*length = len;
510	return (0);
511}
512
513/*
514 * Parse a content-range header
515 */
516static int
517http_parse_range(const char *p, off_t *offset, off_t *length, off_t *size)
518{
519	off_t first, last, len;
520
521	if (strncasecmp(p, "bytes ", 6) != 0)
522		return (-1);
523	p += 6;
524	if (*p == '*') {
525		first = last = -1;
526		++p;
527	} else {
528		for (first = 0; *p && isdigit((int)*p); ++p)
529			first = first * 10 + *p - '0';
530		if (*p != '-')
531			return (-1);
532		for (last = 0, ++p; *p && isdigit((int)*p); ++p)
533			last = last * 10 + *p - '0';
534	}
535	if (first > last || *p != '/')
536		return (-1);
537	for (len = 0, ++p; *p && isdigit((int)*p); ++p)
538		len = len * 10 + *p - '0';
539	if (*p || len < last - first + 1)
540		return (-1);
541	if (first == -1) {
542		DEBUG(fprintf(stderr, "content range: [*/%lld]\n",
543		    (long long)len));
544		*length = 0;
545	} else {
546		DEBUG(fprintf(stderr, "content range: [%lld-%lld/%lld]\n",
547		    (long long)first, (long long)last, (long long)len));
548		*length = last - first + 1;
549	}
550	*offset = first;
551	*size = len;
552	return (0);
553}
554
555
556/*****************************************************************************
557 * Helper functions for authorization
558 */
559
560/*
561 * Base64 encoding
562 */
563static char *
564http_base64(const char *src)
565{
566	static const char base64[] =
567	    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
568	    "abcdefghijklmnopqrstuvwxyz"
569	    "0123456789+/";
570	char *str, *dst;
571	size_t l;
572	int t, r;
573
574	l = strlen(src);
575	if ((str = malloc(((l + 2) / 3) * 4 + 1)) == NULL)
576		return (NULL);
577	dst = str;
578	r = 0;
579
580	while (l >= 3) {
581		t = (src[0] << 16) | (src[1] << 8) | src[2];
582		dst[0] = base64[(t >> 18) & 0x3f];
583		dst[1] = base64[(t >> 12) & 0x3f];
584		dst[2] = base64[(t >> 6) & 0x3f];
585		dst[3] = base64[(t >> 0) & 0x3f];
586		src += 3; l -= 3;
587		dst += 4; r += 4;
588	}
589
590	switch (l) {
591	case 2:
592		t = (src[0] << 16) | (src[1] << 8);
593		dst[0] = base64[(t >> 18) & 0x3f];
594		dst[1] = base64[(t >> 12) & 0x3f];
595		dst[2] = base64[(t >> 6) & 0x3f];
596		dst[3] = '=';
597		dst += 4;
598		r += 4;
599		break;
600	case 1:
601		t = src[0] << 16;
602		dst[0] = base64[(t >> 18) & 0x3f];
603		dst[1] = base64[(t >> 12) & 0x3f];
604		dst[2] = dst[3] = '=';
605		dst += 4;
606		r += 4;
607		break;
608	case 0:
609		break;
610	}
611
612	*dst = 0;
613	return (str);
614}
615
616/*
617 * Encode username and password
618 */
619static int
620http_basic_auth(conn_t *conn, const char *hdr, const char *usr, const char *pwd)
621{
622	char *upw, *auth;
623	int r;
624
625	DEBUG(fprintf(stderr, "usr: [%s]\n", usr));
626	DEBUG(fprintf(stderr, "pwd: [%s]\n", pwd));
627	if (asprintf(&upw, "%s:%s", usr, pwd) == -1)
628		return (-1);
629	auth = http_base64(upw);
630	free(upw);
631	if (auth == NULL)
632		return (-1);
633	r = http_cmd(conn, "%s: Basic %s", hdr, auth);
634	free(auth);
635	return (r);
636}
637
638/*
639 * Send an authorization header
640 */
641static int
642http_authorize(conn_t *conn, const char *hdr, const char *p)
643{
644	/* basic authorization */
645	if (strncasecmp(p, "basic:", 6) == 0) {
646		char *user, *pwd, *str;
647		int r;
648
649		/* skip realm */
650		for (p += 6; *p && *p != ':'; ++p)
651			/* nothing */ ;
652		if (!*p || strchr(++p, ':') == NULL)
653			return (-1);
654		if ((str = strdup(p)) == NULL)
655			return (-1); /* XXX */
656		user = str;
657		pwd = strchr(str, ':');
658		*pwd++ = '\0';
659		r = http_basic_auth(conn, hdr, user, pwd);
660		free(str);
661		return (r);
662	}
663	return (-1);
664}
665
666
667/*****************************************************************************
668 * Helper functions for connecting to a server or proxy
669 */
670
671/*
672 * Connect to the correct HTTP server or proxy.
673 */
674static conn_t *
675http_connect(struct url *URL, struct url *purl, const char *flags)
676{
677	conn_t *conn;
678	int verbose;
679	int af, val;
680
681#ifdef INET6
682	af = AF_UNSPEC;
683#else
684	af = AF_INET;
685#endif
686
687	verbose = CHECK_FLAG('v');
688	if (CHECK_FLAG('4'))
689		af = AF_INET;
690#ifdef INET6
691	else if (CHECK_FLAG('6'))
692		af = AF_INET6;
693#endif
694
695	if (purl && strcasecmp(URL->scheme, SCHEME_HTTPS) != 0) {
696		URL = purl;
697	} else if (strcasecmp(URL->scheme, SCHEME_FTP) == 0) {
698		/* can't talk http to an ftp server */
699		/* XXX should set an error code */
700		return (NULL);
701	}
702
703	if ((conn = fetch_connect(URL->host, URL->port, af, verbose)) == NULL)
704		/* fetch_connect() has already set an error code */
705		return (NULL);
706	if (strcasecmp(URL->scheme, SCHEME_HTTPS) == 0 &&
707	    fetch_ssl(conn, verbose) == -1) {
708		fetch_close(conn);
709		/* grrr */
710		errno = EAUTH;
711		fetch_syserr();
712		return (NULL);
713	}
714
715	val = 1;
716	setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val, sizeof(val));
717
718	return (conn);
719}
720
721static struct url *
722http_get_proxy(const char *flags)
723{
724	struct url *purl;
725	char *p;
726
727	if (flags != NULL && strchr(flags, 'd') != NULL)
728		return (NULL);
729	if (((p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
730	    *p && (purl = fetchParseURL(p))) {
731		if (!*purl->scheme)
732			strcpy(purl->scheme, SCHEME_HTTP);
733		if (!purl->port)
734			purl->port = fetch_default_proxy_port(purl->scheme);
735		if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
736			return (purl);
737		fetchFreeURL(purl);
738	}
739	return (NULL);
740}
741
742static void
743http_print_html(FILE *out, FILE *in)
744{
745	size_t len;
746	char *line, *p, *q;
747	int comment, tag;
748
749	comment = tag = 0;
750	while ((line = fgetln(in, &len)) != NULL) {
751		while (len && isspace((int)line[len - 1]))
752			--len;
753		for (p = q = line; q < line + len; ++q) {
754			if (comment && *q == '-') {
755				if (q + 2 < line + len &&
756				    strcmp(q, "-->") == 0) {
757					tag = comment = 0;
758					q += 2;
759				}
760			} else if (tag && !comment && *q == '>') {
761				p = q + 1;
762				tag = 0;
763			} else if (!tag && *q == '<') {
764				if (q > p)
765					fwrite(p, q - p, 1, out);
766				tag = 1;
767				if (q + 3 < line + len &&
768				    strcmp(q, "<!--") == 0) {
769					comment = 1;
770					q += 3;
771				}
772			}
773		}
774		if (!tag && q > p)
775			fwrite(p, q - p, 1, out);
776		fputc('\n', out);
777	}
778}
779
780
781/*****************************************************************************
782 * Core
783 */
784
785/*
786 * Send a request and process the reply
787 *
788 * XXX This function is way too long, the do..while loop should be split
789 * XXX off into a separate function.
790 */
791FILE *
792http_request(struct url *URL, const char *op, struct url_stat *us,
793    struct url *purl, const char *flags)
794{
795	conn_t *conn;
796	struct url *url, *new;
797	int chunked, direct, need_auth, noredirect, verbose;
798	int e, i, n, val;
799	off_t offset, clength, length, size;
800	time_t mtime;
801	const char *p;
802	FILE *f;
803	hdr_t h;
804	char hbuf[MAXHOSTNAMELEN + 7], *host;
805
806	direct = CHECK_FLAG('d');
807	noredirect = CHECK_FLAG('A');
808	verbose = CHECK_FLAG('v');
809
810	if (direct && purl) {
811		fetchFreeURL(purl);
812		purl = NULL;
813	}
814
815	/* try the provided URL first */
816	url = URL;
817
818	/* if the A flag is set, we only get one try */
819	n = noredirect ? 1 : MAX_REDIRECT;
820	i = 0;
821
822	e = HTTP_PROTOCOL_ERROR;
823	need_auth = 0;
824	do {
825		new = NULL;
826		chunked = 0;
827		offset = 0;
828		clength = -1;
829		length = -1;
830		size = -1;
831		mtime = 0;
832
833		/* check port */
834		if (!url->port)
835			url->port = fetch_default_port(url->scheme);
836
837		/* were we redirected to an FTP URL? */
838		if (purl == NULL && strcmp(url->scheme, SCHEME_FTP) == 0) {
839			if (strcmp(op, "GET") == 0)
840				return (ftp_request(url, "RETR", us, purl, flags));
841			else if (strcmp(op, "HEAD") == 0)
842				return (ftp_request(url, "STAT", us, purl, flags));
843		}
844
845		/* connect to server or proxy */
846		if ((conn = http_connect(url, purl, flags)) == NULL)
847			goto ouch;
848
849		host = url->host;
850#ifdef INET6
851		if (strchr(url->host, ':')) {
852			snprintf(hbuf, sizeof(hbuf), "[%s]", url->host);
853			host = hbuf;
854		}
855#endif
856		if (url->port != fetch_default_port(url->scheme)) {
857			if (host != hbuf) {
858				strcpy(hbuf, host);
859				host = hbuf;
860			}
861			snprintf(hbuf + strlen(hbuf),
862			    sizeof(hbuf) - strlen(hbuf), ":%d", url->port);
863		}
864
865		/* send request */
866		if (verbose)
867			fetch_info("requesting %s://%s%s",
868			    url->scheme, host, url->doc);
869		if (purl) {
870			http_cmd(conn, "%s %s://%s%s HTTP/1.1",
871			    op, url->scheme, host, url->doc);
872		} else {
873			http_cmd(conn, "%s %s HTTP/1.1",
874			    op, url->doc);
875		}
876
877		/* virtual host */
878		http_cmd(conn, "Host: %s", host);
879
880		/* proxy authorization */
881		if (purl) {
882			if (*purl->user || *purl->pwd)
883				http_basic_auth(conn, "Proxy-Authorization",
884				    purl->user, purl->pwd);
885			else if ((p = getenv("HTTP_PROXY_AUTH")) != NULL && *p != '\0')
886				http_authorize(conn, "Proxy-Authorization", p);
887		}
888
889		/* server authorization */
890		if (need_auth || *url->user || *url->pwd) {
891			if (*url->user || *url->pwd)
892				http_basic_auth(conn, "Authorization", url->user, url->pwd);
893			else if ((p = getenv("HTTP_AUTH")) != NULL && *p != '\0')
894				http_authorize(conn, "Authorization", p);
895			else if (fetchAuthMethod && fetchAuthMethod(url) == 0) {
896				http_basic_auth(conn, "Authorization", url->user, url->pwd);
897			} else {
898				http_seterr(HTTP_NEED_AUTH);
899				goto ouch;
900			}
901		}
902
903		/* other headers */
904		if ((p = getenv("HTTP_REFERER")) != NULL && *p != '\0') {
905			if (strcasecmp(p, "auto") == 0)
906				http_cmd(conn, "Referer: %s://%s%s",
907				    url->scheme, host, url->doc);
908			else
909				http_cmd(conn, "Referer: %s", p);
910		}
911		if ((p = getenv("HTTP_USER_AGENT")) != NULL && *p != '\0')
912			http_cmd(conn, "User-Agent: %s", p);
913		else
914			http_cmd(conn, "User-Agent: %s " _LIBFETCH_VER, getprogname());
915		if (url->offset > 0)
916			http_cmd(conn, "Range: bytes=%lld-", (long long)url->offset);
917		http_cmd(conn, "Connection: close");
918		http_cmd(conn, "");
919
920		/*
921		 * Force the queued request to be dispatched.  Normally, one
922		 * would do this with shutdown(2) but squid proxies can be
923		 * configured to disallow such half-closed connections.  To
924		 * be compatible with such configurations, fiddle with socket
925		 * options to force the pending data to be written.
926		 */
927		val = 0;
928		setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val,
929			   sizeof(val));
930		val = 1;
931		setsockopt(conn->sd, IPPROTO_TCP, TCP_NODELAY, &val,
932			   sizeof(val));
933
934		/* get reply */
935		switch (http_get_reply(conn)) {
936		case HTTP_OK:
937		case HTTP_PARTIAL:
938			/* fine */
939			break;
940		case HTTP_MOVED_PERM:
941		case HTTP_MOVED_TEMP:
942		case HTTP_SEE_OTHER:
943			/*
944			 * Not so fine, but we still have to read the
945			 * headers to get the new location.
946			 */
947			break;
948		case HTTP_NEED_AUTH:
949			if (need_auth) {
950				/*
951				 * We already sent out authorization code,
952				 * so there's nothing more we can do.
953				 */
954				http_seterr(conn->err);
955				goto ouch;
956			}
957			/* try again, but send the password this time */
958			if (verbose)
959				fetch_info("server requires authorization");
960			break;
961		case HTTP_NEED_PROXY_AUTH:
962			/*
963			 * If we're talking to a proxy, we already sent
964			 * our proxy authorization code, so there's
965			 * nothing more we can do.
966			 */
967			http_seterr(conn->err);
968			goto ouch;
969		case HTTP_BAD_RANGE:
970			/*
971			 * This can happen if we ask for 0 bytes because
972			 * we already have the whole file.  Consider this
973			 * a success for now, and check sizes later.
974			 */
975			break;
976		case HTTP_PROTOCOL_ERROR:
977			/* fall through */
978		case -1:
979			fetch_syserr();
980			goto ouch;
981		default:
982			http_seterr(conn->err);
983			if (!verbose)
984				goto ouch;
985			/* fall through so we can get the full error message */
986		}
987
988		/* get headers */
989		do {
990			switch ((h = http_next_header(conn, &p))) {
991			case hdr_syserror:
992				fetch_syserr();
993				goto ouch;
994			case hdr_error:
995				http_seterr(HTTP_PROTOCOL_ERROR);
996				goto ouch;
997			case hdr_content_length:
998				http_parse_length(p, &clength);
999				break;
1000			case hdr_content_range:
1001				http_parse_range(p, &offset, &length, &size);
1002				break;
1003			case hdr_last_modified:
1004				http_parse_mtime(p, &mtime);
1005				break;
1006			case hdr_location:
1007				if (!HTTP_REDIRECT(conn->err))
1008					break;
1009				if (new)
1010					free(new);
1011				if (verbose)
1012					fetch_info("%d redirect to %s", conn->err, p);
1013				if (*p == '/')
1014					/* absolute path */
1015					new = fetchMakeURL(url->scheme, url->host, url->port, p,
1016					    url->user, url->pwd);
1017				else
1018					new = fetchParseURL(p);
1019				if (new == NULL) {
1020					/* XXX should set an error code */
1021					DEBUG(fprintf(stderr, "failed to parse new URL\n"));
1022					goto ouch;
1023				}
1024				if (!*new->user && !*new->pwd) {
1025					strcpy(new->user, url->user);
1026					strcpy(new->pwd, url->pwd);
1027				}
1028				new->offset = url->offset;
1029				new->length = url->length;
1030				break;
1031			case hdr_transfer_encoding:
1032				/* XXX weak test*/
1033				chunked = (strcasecmp(p, "chunked") == 0);
1034				break;
1035			case hdr_www_authenticate:
1036				if (conn->err != HTTP_NEED_AUTH)
1037					break;
1038				/* if we were smarter, we'd check the method and realm */
1039				break;
1040			case hdr_end:
1041				/* fall through */
1042			case hdr_unknown:
1043				/* ignore */
1044				break;
1045			}
1046		} while (h > hdr_end);
1047
1048		/* we need to provide authentication */
1049		if (conn->err == HTTP_NEED_AUTH) {
1050			e = conn->err;
1051			need_auth = 1;
1052			fetch_close(conn);
1053			conn = NULL;
1054			continue;
1055		}
1056
1057		/* requested range not satisfiable */
1058		if (conn->err == HTTP_BAD_RANGE) {
1059			if (url->offset == size && url->length == 0) {
1060				/* asked for 0 bytes; fake it */
1061				offset = url->offset;
1062				conn->err = HTTP_OK;
1063				break;
1064			} else {
1065				http_seterr(conn->err);
1066				goto ouch;
1067			}
1068		}
1069
1070		/* we have a hit or an error */
1071		if (conn->err == HTTP_OK || conn->err == HTTP_PARTIAL || HTTP_ERROR(conn->err))
1072			break;
1073
1074		/* all other cases: we got a redirect */
1075		e = conn->err;
1076		need_auth = 0;
1077		fetch_close(conn);
1078		conn = NULL;
1079		if (!new) {
1080			DEBUG(fprintf(stderr, "redirect with no new location\n"));
1081			break;
1082		}
1083		if (url != URL)
1084			fetchFreeURL(url);
1085		url = new;
1086	} while (++i < n);
1087
1088	/* we failed, or ran out of retries */
1089	if (conn == NULL) {
1090		http_seterr(e);
1091		goto ouch;
1092	}
1093
1094	DEBUG(fprintf(stderr, "offset %lld, length %lld,"
1095		  " size %lld, clength %lld\n",
1096		  (long long)offset, (long long)length,
1097		  (long long)size, (long long)clength));
1098
1099	/* check for inconsistencies */
1100	if (clength != -1 && length != -1 && clength != length) {
1101		http_seterr(HTTP_PROTOCOL_ERROR);
1102		goto ouch;
1103	}
1104	if (clength == -1)
1105		clength = length;
1106	if (clength != -1)
1107		length = offset + clength;
1108	if (length != -1 && size != -1 && length != size) {
1109		http_seterr(HTTP_PROTOCOL_ERROR);
1110		goto ouch;
1111	}
1112	if (size == -1)
1113		size = length;
1114
1115	/* fill in stats */
1116	if (us) {
1117		us->size = size;
1118		us->atime = us->mtime = mtime;
1119	}
1120
1121	/* too far? */
1122	if (URL->offset > 0 && offset > URL->offset) {
1123		http_seterr(HTTP_PROTOCOL_ERROR);
1124		goto ouch;
1125	}
1126
1127	/* report back real offset and size */
1128	URL->offset = offset;
1129	URL->length = clength;
1130
1131	/* wrap it up in a FILE */
1132	if ((f = http_funopen(conn, chunked)) == NULL) {
1133		fetch_syserr();
1134		goto ouch;
1135	}
1136
1137	if (url != URL)
1138		fetchFreeURL(url);
1139	if (purl)
1140		fetchFreeURL(purl);
1141
1142	if (HTTP_ERROR(conn->err)) {
1143		http_print_html(stderr, f);
1144		fclose(f);
1145		f = NULL;
1146	}
1147
1148	return (f);
1149
1150ouch:
1151	if (url != URL)
1152		fetchFreeURL(url);
1153	if (purl)
1154		fetchFreeURL(purl);
1155	if (conn != NULL)
1156		fetch_close(conn);
1157	return (NULL);
1158}
1159
1160
1161/*****************************************************************************
1162 * Entry points
1163 */
1164
1165/*
1166 * Retrieve and stat a file by HTTP
1167 */
1168FILE *
1169fetchXGetHTTP(struct url *URL, struct url_stat *us, const char *flags)
1170{
1171	return (http_request(URL, "GET", us, http_get_proxy(flags), flags));
1172}
1173
1174/*
1175 * Retrieve a file by HTTP
1176 */
1177FILE *
1178fetchGetHTTP(struct url *URL, const char *flags)
1179{
1180	return (fetchXGetHTTP(URL, NULL, flags));
1181}
1182
1183/*
1184 * Store a file by HTTP
1185 */
1186FILE *
1187fetchPutHTTP(struct url *URL __unused, const char *flags __unused)
1188{
1189	warnx("fetchPutHTTP(): not implemented");
1190	return (NULL);
1191}
1192
1193/*
1194 * Get an HTTP document's metadata
1195 */
1196int
1197fetchStatHTTP(struct url *URL, struct url_stat *us, const char *flags)
1198{
1199	FILE *f;
1200
1201	f = http_request(URL, "HEAD", us, http_get_proxy(flags), flags);
1202	if (f == NULL)
1203		return (-1);
1204	fclose(f);
1205	return (0);
1206}
1207
1208/*
1209 * List a directory
1210 */
1211struct url_ent *
1212fetchListHTTP(struct url *url __unused, const char *flags __unused)
1213{
1214	warnx("fetchListHTTP(): not implemented");
1215	return (NULL);
1216}
1217