http.c revision 174588 
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 174588 2007-12-14 10:26:58Z 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 || !ishexnumber(*io->conn->buf))
141		return (-1);
142
143	for (p = io->conn->buf; *p && !isspace(*p); ++p) {
144		if (*p == ';')
145			break;
146		if (!ishexnumber(*p))
147			return (-1);
148		if (isdigit(*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(p[1]) || !isdigit(p[2]) || !isdigit(p[3]))
421		return (HTTP_PROTOCOL_ERROR);
422
423	conn->err = (p[1] - '0') * 100 + (p[2] - '0') * 10 + (p[3] - '0');
424	return (conn->err);
425}
426
427/*
428 * Check a header; if the type matches the given string, return a pointer
429 * to the beginning of the value.
430 */
431static const char *
432http_match(const char *str, const char *hdr)
433{
434	while (*str && *hdr && tolower(*str++) == tolower(*hdr++))
435		/* nothing */;
436	if (*str || *hdr != ':')
437		return (NULL);
438	while (*hdr && isspace(*++hdr))
439		/* nothing */;
440	return (hdr);
441}
442
443/*
444 * Get the next header and return the appropriate symbolic code.
445 */
446static hdr_t
447http_next_header(conn_t *conn, const char **p)
448{
449	int i;
450
451	if (fetch_getln(conn) == -1)
452		return (hdr_syserror);
453	while (conn->buflen && isspace(conn->buf[conn->buflen - 1]))
454		conn->buflen--;
455	conn->buf[conn->buflen] = '\0';
456	if (conn->buflen == 0)
457		return (hdr_end);
458	/*
459	 * We could check for malformed headers but we don't really care.
460	 * A valid header starts with a token immediately followed by a
461	 * colon; a token is any sequence of non-control, non-whitespace
462	 * characters except "()<>@,;:\\\"{}".
463	 */
464	for (i = 0; hdr_names[i].num != hdr_unknown; i++)
465		if ((*p = http_match(hdr_names[i].name, conn->buf)) != NULL)
466			return (hdr_names[i].num);
467	return (hdr_unknown);
468}
469
470/*
471 * Parse a last-modified header
472 */
473static int
474http_parse_mtime(const char *p, time_t *mtime)
475{
476	char locale[64], *r;
477	struct tm tm;
478
479	strncpy(locale, setlocale(LC_TIME, NULL), sizeof(locale));
480	setlocale(LC_TIME, "C");
481	r = strptime(p, "%a, %d %b %Y %H:%M:%S GMT", &tm);
482	/* XXX should add support for date-2 and date-3 */
483	setlocale(LC_TIME, locale);
484	if (r == NULL)
485		return (-1);
486	DEBUG(fprintf(stderr, "last modified: [%04d-%02d-%02d "
487		  "%02d:%02d:%02d]\n",
488		  tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
489		  tm.tm_hour, tm.tm_min, tm.tm_sec));
490	*mtime = timegm(&tm);
491	return (0);
492}
493
494/*
495 * Parse a content-length header
496 */
497static int
498http_parse_length(const char *p, off_t *length)
499{
500	off_t len;
501
502	for (len = 0; *p && isdigit(*p); ++p)
503		len = len * 10 + (*p - '0');
504	if (*p)
505		return (-1);
506	DEBUG(fprintf(stderr, "content length: [%lld]\n",
507	    (long long)len));
508	*length = len;
509	return (0);
510}
511
512/*
513 * Parse a content-range header
514 */
515static int
516http_parse_range(const char *p, off_t *offset, off_t *length, off_t *size)
517{
518	off_t first, last, len;
519
520	if (strncasecmp(p, "bytes ", 6) != 0)
521		return (-1);
522	p += 6;
523	if (*p == '*') {
524		first = last = -1;
525		++p;
526	} else {
527		for (first = 0; *p && isdigit(*p); ++p)
528			first = first * 10 + *p - '0';
529		if (*p != '-')
530			return (-1);
531		for (last = 0, ++p; *p && isdigit(*p); ++p)
532			last = last * 10 + *p - '0';
533	}
534	if (first > last || *p != '/')
535		return (-1);
536	for (len = 0, ++p; *p && isdigit(*p); ++p)
537		len = len * 10 + *p - '0';
538	if (*p || len < last - first + 1)
539		return (-1);
540	if (first == -1) {
541		DEBUG(fprintf(stderr, "content range: [*/%lld]\n",
542		    (long long)len));
543		*length = 0;
544	} else {
545		DEBUG(fprintf(stderr, "content range: [%lld-%lld/%lld]\n",
546		    (long long)first, (long long)last, (long long)len));
547		*length = last - first + 1;
548	}
549	*offset = first;
550	*size = len;
551	return (0);
552}
553
554
555/*****************************************************************************
556 * Helper functions for authorization
557 */
558
559/*
560 * Base64 encoding
561 */
562static char *
563http_base64(const char *src)
564{
565	static const char base64[] =
566	    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
567	    "abcdefghijklmnopqrstuvwxyz"
568	    "0123456789+/";
569	char *str, *dst;
570	size_t l;
571	int t, r;
572
573	l = strlen(src);
574	if ((str = malloc(((l + 2) / 3) * 4 + 1)) == NULL)
575		return (NULL);
576	dst = str;
577	r = 0;
578
579	while (l >= 3) {
580		t = (src[0] << 16) | (src[1] << 8) | src[2];
581		dst[0] = base64[(t >> 18) & 0x3f];
582		dst[1] = base64[(t >> 12) & 0x3f];
583		dst[2] = base64[(t >> 6) & 0x3f];
584		dst[3] = base64[(t >> 0) & 0x3f];
585		src += 3; l -= 3;
586		dst += 4; r += 4;
587	}
588
589	switch (l) {
590	case 2:
591		t = (src[0] << 16) | (src[1] << 8);
592		dst[0] = base64[(t >> 18) & 0x3f];
593		dst[1] = base64[(t >> 12) & 0x3f];
594		dst[2] = base64[(t >> 6) & 0x3f];
595		dst[3] = '=';
596		dst += 4;
597		r += 4;
598		break;
599	case 1:
600		t = src[0] << 16;
601		dst[0] = base64[(t >> 18) & 0x3f];
602		dst[1] = base64[(t >> 12) & 0x3f];
603		dst[2] = dst[3] = '=';
604		dst += 4;
605		r += 4;
606		break;
607	case 0:
608		break;
609	}
610
611	*dst = 0;
612	return (str);
613}
614
615/*
616 * Encode username and password
617 */
618static int
619http_basic_auth(conn_t *conn, const char *hdr, const char *usr, const char *pwd)
620{
621	char *upw, *auth;
622	int r;
623
624	DEBUG(fprintf(stderr, "usr: [%s]\n", usr));
625	DEBUG(fprintf(stderr, "pwd: [%s]\n", pwd));
626	if (asprintf(&upw, "%s:%s", usr, pwd) == -1)
627		return (-1);
628	auth = http_base64(upw);
629	free(upw);
630	if (auth == NULL)
631		return (-1);
632	r = http_cmd(conn, "%s: Basic %s", hdr, auth);
633	free(auth);
634	return (r);
635}
636
637/*
638 * Send an authorization header
639 */
640static int
641http_authorize(conn_t *conn, const char *hdr, const char *p)
642{
643	/* basic authorization */
644	if (strncasecmp(p, "basic:", 6) == 0) {
645		char *user, *pwd, *str;
646		int r;
647
648		/* skip realm */
649		for (p += 6; *p && *p != ':'; ++p)
650			/* nothing */ ;
651		if (!*p || strchr(++p, ':') == NULL)
652			return (-1);
653		if ((str = strdup(p)) == NULL)
654			return (-1); /* XXX */
655		user = str;
656		pwd = strchr(str, ':');
657		*pwd++ = '\0';
658		r = http_basic_auth(conn, hdr, user, pwd);
659		free(str);
660		return (r);
661	}
662	return (-1);
663}
664
665
666/*****************************************************************************
667 * Helper functions for connecting to a server or proxy
668 */
669
670/*
671 * Connect to the correct HTTP server or proxy.
672 */
673static conn_t *
674http_connect(struct url *URL, struct url *purl, const char *flags)
675{
676	conn_t *conn;
677	int verbose;
678	int af, val;
679
680#ifdef INET6
681	af = AF_UNSPEC;
682#else
683	af = AF_INET;
684#endif
685
686	verbose = CHECK_FLAG('v');
687	if (CHECK_FLAG('4'))
688		af = AF_INET;
689#ifdef INET6
690	else if (CHECK_FLAG('6'))
691		af = AF_INET6;
692#endif
693
694	if (purl && strcasecmp(URL->scheme, SCHEME_HTTPS) != 0) {
695		URL = purl;
696	} else if (strcasecmp(URL->scheme, SCHEME_FTP) == 0) {
697		/* can't talk http to an ftp server */
698		/* XXX should set an error code */
699		return (NULL);
700	}
701
702	if ((conn = fetch_connect(URL->host, URL->port, af, verbose)) == NULL)
703		/* fetch_connect() has already set an error code */
704		return (NULL);
705	if (strcasecmp(URL->scheme, SCHEME_HTTPS) == 0 &&
706	    fetch_ssl(conn, verbose) == -1) {
707		fetch_close(conn);
708		/* grrr */
709		errno = EAUTH;
710		fetch_syserr();
711		return (NULL);
712	}
713
714	val = 1;
715	setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val, sizeof(val));
716
717	return (conn);
718}
719
720static struct url *
721http_get_proxy(const char *flags)
722{
723	struct url *purl;
724	char *p;
725
726	if (flags != NULL && strchr(flags, 'd') != NULL)
727		return (NULL);
728	if (((p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
729	    *p && (purl = fetchParseURL(p))) {
730		if (!*purl->scheme)
731			strcpy(purl->scheme, SCHEME_HTTP);
732		if (!purl->port)
733			purl->port = fetch_default_proxy_port(purl->scheme);
734		if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
735			return (purl);
736		fetchFreeURL(purl);
737	}
738	return (NULL);
739}
740
741static void
742http_print_html(FILE *out, FILE *in)
743{
744	size_t len;
745	char *line, *p, *q;
746	int comment, tag;
747
748	comment = tag = 0;
749	while ((line = fgetln(in, &len)) != NULL) {
750		while (len && isspace(line[len - 1]))
751			--len;
752		for (p = q = line; q < line + len; ++q) {
753			if (comment && *q == '-') {
754				if (q + 2 < line + len &&
755				    strcmp(q, "-->") == 0) {
756					tag = comment = 0;
757					q += 2;
758				}
759			} else if (tag && !comment && *q == '>') {
760				p = q + 1;
761				tag = 0;
762			} else if (!tag && *q == '<') {
763				if (q > p)
764					fwrite(p, q - p, 1, out);
765				tag = 1;
766				if (q + 3 < line + len &&
767				    strcmp(q, "<!--") == 0) {
768					comment = 1;
769					q += 3;
770				}
771			}
772		}
773		if (!tag && q > p)
774			fwrite(p, q - p, 1, out);
775		fputc('\n', out);
776	}
777}
778
779
780/*****************************************************************************
781 * Core
782 */
783
784/*
785 * Send a request and process the reply
786 *
787 * XXX This function is way too long, the do..while loop should be split
788 * XXX off into a separate function.
789 */
790FILE *
791http_request(struct url *URL, const char *op, struct url_stat *us,
792    struct url *purl, const char *flags)
793{
794	conn_t *conn;
795	struct url *url, *new;
796	int chunked, direct, need_auth, noredirect, verbose;
797	int e, i, n, val;
798	off_t offset, clength, length, size;
799	time_t mtime;
800	const char *p;
801	FILE *f;
802	hdr_t h;
803	char hbuf[MAXHOSTNAMELEN + 7], *host;
804
805	direct = CHECK_FLAG('d');
806	noredirect = CHECK_FLAG('A');
807	verbose = CHECK_FLAG('v');
808
809	if (direct && purl) {
810		fetchFreeURL(purl);
811		purl = NULL;
812	}
813
814	/* try the provided URL first */
815	url = URL;
816
817	/* if the A flag is set, we only get one try */
818	n = noredirect ? 1 : MAX_REDIRECT;
819	i = 0;
820
821	e = HTTP_PROTOCOL_ERROR;
822	need_auth = 0;
823	do {
824		new = NULL;
825		chunked = 0;
826		offset = 0;
827		clength = -1;
828		length = -1;
829		size = -1;
830		mtime = 0;
831
832		/* check port */
833		if (!url->port)
834			url->port = fetch_default_port(url->scheme);
835
836		/* were we redirected to an FTP URL? */
837		if (purl == NULL && strcmp(url->scheme, SCHEME_FTP) == 0) {
838			if (strcmp(op, "GET") == 0)
839				return (ftp_request(url, "RETR", us, purl, flags));
840			else if (strcmp(op, "HEAD") == 0)
841				return (ftp_request(url, "STAT", us, purl, flags));
842		}
843
844		/* connect to server or proxy */
845		if ((conn = http_connect(url, purl, flags)) == NULL)
846			goto ouch;
847
848		host = url->host;
849#ifdef INET6
850		if (strchr(url->host, ':')) {
851			snprintf(hbuf, sizeof(hbuf), "[%s]", url->host);
852			host = hbuf;
853		}
854#endif
855		if (url->port != fetch_default_port(url->scheme)) {
856			if (host != hbuf) {
857				strcpy(hbuf, host);
858				host = hbuf;
859			}
860			snprintf(hbuf + strlen(hbuf),
861			    sizeof(hbuf) - strlen(hbuf), ":%d", url->port);
862		}
863
864		/* send request */
865		if (verbose)
866			fetch_info("requesting %s://%s%s",
867			    url->scheme, host, url->doc);
868		if (purl) {
869			http_cmd(conn, "%s %s://%s%s HTTP/1.1",
870			    op, url->scheme, host, url->doc);
871		} else {
872			http_cmd(conn, "%s %s HTTP/1.1",
873			    op, url->doc);
874		}
875
876		/* virtual host */
877		http_cmd(conn, "Host: %s", host);
878
879		/* proxy authorization */
880		if (purl) {
881			if (*purl->user || *purl->pwd)
882				http_basic_auth(conn, "Proxy-Authorization",
883				    purl->user, purl->pwd);
884			else if ((p = getenv("HTTP_PROXY_AUTH")) != NULL && *p != '\0')
885				http_authorize(conn, "Proxy-Authorization", p);
886		}
887
888		/* server authorization */
889		if (need_auth || *url->user || *url->pwd) {
890			if (*url->user || *url->pwd)
891				http_basic_auth(conn, "Authorization", url->user, url->pwd);
892			else if ((p = getenv("HTTP_AUTH")) != NULL && *p != '\0')
893				http_authorize(conn, "Authorization", p);
894			else if (fetchAuthMethod && fetchAuthMethod(url) == 0) {
895				http_basic_auth(conn, "Authorization", url->user, url->pwd);
896			} else {
897				http_seterr(HTTP_NEED_AUTH);
898				goto ouch;
899			}
900		}
901
902		/* other headers */
903		if ((p = getenv("HTTP_REFERER")) != NULL && *p != '\0') {
904			if (strcasecmp(p, "auto") == 0)
905				http_cmd(conn, "Referer: %s://%s%s",
906				    url->scheme, host, url->doc);
907			else
908				http_cmd(conn, "Referer: %s", p);
909		}
910		if ((p = getenv("HTTP_USER_AGENT")) != NULL && *p != '\0')
911			http_cmd(conn, "User-Agent: %s", p);
912		else
913			http_cmd(conn, "User-Agent: %s " _LIBFETCH_VER, getprogname());
914		if (url->offset > 0)
915			http_cmd(conn, "Range: bytes=%lld-", (long long)url->offset);
916		http_cmd(conn, "Connection: close");
917		http_cmd(conn, "");
918
919		/*
920		 * Force the queued request to be dispatched.  Normally, one
921		 * would do this with shutdown(2) but squid proxies can be
922		 * configured to disallow such half-closed connections.  To
923		 * be compatible with such configurations, fiddle with socket
924		 * options to force the pending data to be written.
925		 */
926		val = 0;
927		setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val,
928			   sizeof(val));
929		val = 1;
930		setsockopt(conn->sd, IPPROTO_TCP, TCP_NODELAY, &val,
931			   sizeof(val));
932
933		/* get reply */
934		switch (http_get_reply(conn)) {
935		case HTTP_OK:
936		case HTTP_PARTIAL:
937			/* fine */
938			break;
939		case HTTP_MOVED_PERM:
940		case HTTP_MOVED_TEMP:
941		case HTTP_SEE_OTHER:
942			/*
943			 * Not so fine, but we still have to read the
944			 * headers to get the new location.
945			 */
946			break;
947		case HTTP_NEED_AUTH:
948			if (need_auth) {
949				/*
950				 * We already sent out authorization code,
951				 * so there's nothing more we can do.
952				 */
953				http_seterr(conn->err);
954				goto ouch;
955			}
956			/* try again, but send the password this time */
957			if (verbose)
958				fetch_info("server requires authorization");
959			break;
960		case HTTP_NEED_PROXY_AUTH:
961			/*
962			 * If we're talking to a proxy, we already sent
963			 * our proxy authorization code, so there's
964			 * nothing more we can do.
965			 */
966			http_seterr(conn->err);
967			goto ouch;
968		case HTTP_BAD_RANGE:
969			/*
970			 * This can happen if we ask for 0 bytes because
971			 * we already have the whole file.  Consider this
972			 * a success for now, and check sizes later.
973			 */
974			break;
975		case HTTP_PROTOCOL_ERROR:
976			/* fall through */
977		case -1:
978			fetch_syserr();
979			goto ouch;
980		default:
981			http_seterr(conn->err);
982			if (!verbose)
983				goto ouch;
984			/* fall through so we can get the full error message */
985		}
986
987		/* get headers */
988		do {
989			switch ((h = http_next_header(conn, &p))) {
990			case hdr_syserror:
991				fetch_syserr();
992				goto ouch;
993			case hdr_error:
994				http_seterr(HTTP_PROTOCOL_ERROR);
995				goto ouch;
996			case hdr_content_length:
997				http_parse_length(p, &clength);
998				break;
999			case hdr_content_range:
1000				http_parse_range(p, &offset, &length, &size);
1001				break;
1002			case hdr_last_modified:
1003				http_parse_mtime(p, &mtime);
1004				break;
1005			case hdr_location:
1006				if (!HTTP_REDIRECT(conn->err))
1007					break;
1008				if (new)
1009					free(new);
1010				if (verbose)
1011					fetch_info("%d redirect to %s", conn->err, p);
1012				if (*p == '/')
1013					/* absolute path */
1014					new = fetchMakeURL(url->scheme, url->host, url->port, p,
1015					    url->user, url->pwd);
1016				else
1017					new = fetchParseURL(p);
1018				if (new == NULL) {
1019					/* XXX should set an error code */
1020					DEBUG(fprintf(stderr, "failed to parse new URL\n"));
1021					goto ouch;
1022				}
1023				if (!*new->user && !*new->pwd) {
1024					strcpy(new->user, url->user);
1025					strcpy(new->pwd, url->pwd);
1026				}
1027				new->offset = url->offset;
1028				new->length = url->length;
1029				break;
1030			case hdr_transfer_encoding:
1031				/* XXX weak test*/
1032				chunked = (strcasecmp(p, "chunked") == 0);
1033				break;
1034			case hdr_www_authenticate:
1035				if (conn->err != HTTP_NEED_AUTH)
1036					break;
1037				/* if we were smarter, we'd check the method and realm */
1038				break;
1039			case hdr_end:
1040				/* fall through */
1041			case hdr_unknown:
1042				/* ignore */
1043				break;
1044			}
1045		} while (h > hdr_end);
1046
1047		/* we need to provide authentication */
1048		if (conn->err == HTTP_NEED_AUTH) {
1049			e = conn->err;
1050			need_auth = 1;
1051			fetch_close(conn);
1052			conn = NULL;
1053			continue;
1054		}
1055
1056		/* requested range not satisfiable */
1057		if (conn->err == HTTP_BAD_RANGE) {
1058			if (url->offset == size && url->length == 0) {
1059				/* asked for 0 bytes; fake it */
1060				offset = url->offset;
1061				conn->err = HTTP_OK;
1062				break;
1063			} else {
1064				http_seterr(conn->err);
1065				goto ouch;
1066			}
1067		}
1068
1069		/* we have a hit or an error */
1070		if (conn->err == HTTP_OK || conn->err == HTTP_PARTIAL || HTTP_ERROR(conn->err))
1071			break;
1072
1073		/* all other cases: we got a redirect */
1074		e = conn->err;
1075		need_auth = 0;
1076		fetch_close(conn);
1077		conn = NULL;
1078		if (!new) {
1079			DEBUG(fprintf(stderr, "redirect with no new location\n"));
1080			break;
1081		}
1082		if (url != URL)
1083			fetchFreeURL(url);
1084		url = new;
1085	} while (++i < n);
1086
1087	/* we failed, or ran out of retries */
1088	if (conn == NULL) {
1089		http_seterr(e);
1090		goto ouch;
1091	}
1092
1093	DEBUG(fprintf(stderr, "offset %lld, length %lld,"
1094		  " size %lld, clength %lld\n",
1095		  (long long)offset, (long long)length,
1096		  (long long)size, (long long)clength));
1097
1098	/* check for inconsistencies */
1099	if (clength != -1 && length != -1 && clength != length) {
1100		http_seterr(HTTP_PROTOCOL_ERROR);
1101		goto ouch;
1102	}
1103	if (clength == -1)
1104		clength = length;
1105	if (clength != -1)
1106		length = offset + clength;
1107	if (length != -1 && size != -1 && length != size) {
1108		http_seterr(HTTP_PROTOCOL_ERROR);
1109		goto ouch;
1110	}
1111	if (size == -1)
1112		size = length;
1113
1114	/* fill in stats */
1115	if (us) {
1116		us->size = size;
1117		us->atime = us->mtime = mtime;
1118	}
1119
1120	/* too far? */
1121	if (URL->offset > 0 && offset > URL->offset) {
1122		http_seterr(HTTP_PROTOCOL_ERROR);
1123		goto ouch;
1124	}
1125
1126	/* report back real offset and size */
1127	URL->offset = offset;
1128	URL->length = clength;
1129
1130	/* wrap it up in a FILE */
1131	if ((f = http_funopen(conn, chunked)) == NULL) {
1132		fetch_syserr();
1133		goto ouch;
1134	}
1135
1136	if (url != URL)
1137		fetchFreeURL(url);
1138	if (purl)
1139		fetchFreeURL(purl);
1140
1141	if (HTTP_ERROR(conn->err)) {
1142		http_print_html(stderr, f);
1143		fclose(f);
1144		f = NULL;
1145	}
1146
1147	return (f);
1148
1149ouch:
1150	if (url != URL)
1151		fetchFreeURL(url);
1152	if (purl)
1153		fetchFreeURL(purl);
1154	if (conn != NULL)
1155		fetch_close(conn);
1156	return (NULL);
1157}
1158
1159
1160/*****************************************************************************
1161 * Entry points
1162 */
1163
1164/*
1165 * Retrieve and stat a file by HTTP
1166 */
1167FILE *
1168fetchXGetHTTP(struct url *URL, struct url_stat *us, const char *flags)
1169{
1170	return (http_request(URL, "GET", us, http_get_proxy(flags), flags));
1171}
1172
1173/*
1174 * Retrieve a file by HTTP
1175 */
1176FILE *
1177fetchGetHTTP(struct url *URL, const char *flags)
1178{
1179	return (fetchXGetHTTP(URL, NULL, flags));
1180}
1181
1182/*
1183 * Store a file by HTTP
1184 */
1185FILE *
1186fetchPutHTTP(struct url *URL __unused, const char *flags __unused)
1187{
1188	warnx("fetchPutHTTP(): not implemented");
1189	return (NULL);
1190}
1191
1192/*
1193 * Get an HTTP document's metadata
1194 */
1195int
1196fetchStatHTTP(struct url *URL, struct url_stat *us, const char *flags)
1197{
1198	FILE *f;
1199
1200	f = http_request(URL, "HEAD", us, http_get_proxy(flags), flags);
1201	if (f == NULL)
1202		return (-1);
1203	fclose(f);
1204	return (0);
1205}
1206
1207/*
1208 * List a directory
1209 */
1210struct url_ent *
1211fetchListHTTP(struct url *url __unused, const char *flags __unused)
1212{
1213	warnx("fetchListHTTP(): not implemented");
1214	return (NULL);
1215}
1216