xref: /freebsd/lib/libfetch/http.c (revision b601c69bdbe8755d26570261d7fd4c02ee4eff74)
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  *      $FreeBSD$
29  */
30 
31 /*
32  * The following copyright applies to the base64 code:
33  *
34  *-
35  * Copyright 1997 Massachusetts Institute of Technology
36  *
37  * Permission to use, copy, modify, and distribute this software and
38  * its documentation for any purpose and without fee is hereby
39  * granted, provided that both the above copyright notice and this
40  * permission notice appear in all copies, that both the above
41  * copyright notice and this permission notice appear in all
42  * supporting documentation, and that the name of M.I.T. not be used
43  * in advertising or publicity pertaining to distribution of the
44  * software without specific, written prior permission.  M.I.T. makes
45  * no representations about the suitability of this software for any
46  * purpose.  It is provided "as is" without express or implied
47  * warranty.
48  *
49  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
50  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
51  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
52  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
53  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
54  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
55  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
56  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
57  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
58  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
59  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
60  * SUCH DAMAGE.
61  */
62 
63 #include <sys/param.h>
64 #include <sys/socket.h>
65 
66 #include <ctype.h>
67 #include <err.h>
68 #include <errno.h>
69 #include <locale.h>
70 #include <netdb.h>
71 #include <stdarg.h>
72 #include <stdio.h>
73 #include <stdlib.h>
74 #include <string.h>
75 #include <time.h>
76 #include <unistd.h>
77 
78 #include "fetch.h"
79 #include "common.h"
80 #include "httperr.h"
81 
82 extern char *__progname; /* XXX not portable */
83 
84 /* Maximum number of redirects to follow */
85 #define MAX_REDIRECT 5
86 
87 /* Symbolic names for reply codes we care about */
88 #define HTTP_OK			200
89 #define HTTP_PARTIAL		206
90 #define HTTP_MOVED_PERM		301
91 #define HTTP_MOVED_TEMP		302
92 #define HTTP_SEE_OTHER		303
93 #define HTTP_NEED_AUTH		401
94 #define HTTP_NEED_PROXY_AUTH	403
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 
102 
103 /*****************************************************************************
104  * I/O functions for decoding chunked streams
105  */
106 
107 struct cookie
108 {
109     int		 fd;
110     char	*buf;
111     size_t	 b_size;
112     size_t	 b_len;
113     int		 b_pos;
114     int		 eof;
115     int		 error;
116     long	 chunksize;
117 #ifndef NDEBUG
118     long	 total;
119 #endif
120 };
121 
122 /*
123  * Get next chunk header
124  */
125 static int
126 _http_new_chunk(struct cookie *c)
127 {
128     char *p;
129 
130     if (_fetch_getln(c->fd, &c->buf, &c->b_size, &c->b_len) == -1)
131 	return -1;
132 
133     if (c->b_len < 2 || !ishexnumber(*c->buf))
134 	return -1;
135 
136     for (p = c->buf; !isspace(*p) && *p != ';' && p < c->buf + c->b_len; ++p)
137 	if (!ishexnumber(*p))
138 	    return -1;
139 	else if (isdigit(*p))
140 	    c->chunksize = c->chunksize * 16 + *p - '0';
141 	else
142 	    c->chunksize = c->chunksize * 16 + 10 + tolower(*p) - 'a';
143 
144 #ifndef NDEBUG
145     c->total += c->chunksize;
146     if (c->chunksize == 0)
147 	fprintf(stderr, "\033[1m_http_fillbuf(): "
148 		"end of last chunk\033[m\n");
149     else
150 	fprintf(stderr, "\033[1m_http_fillbuf(): "
151 		"new chunk: %ld (%ld)\033[m\n", c->chunksize, c->total);
152 #endif
153 
154     return c->chunksize;
155 }
156 
157 /*
158  * Fill the input buffer, do chunk decoding on the fly
159  */
160 static int
161 _http_fillbuf(struct cookie *c)
162 {
163     if (c->error)
164 	return -1;
165     if (c->eof)
166 	return 0;
167 
168     if (c->chunksize == 0) {
169 	switch (_http_new_chunk(c)) {
170 	case -1:
171 	    c->error = 1;
172 	    return -1;
173 	case 0:
174 	    c->eof = 1;
175 	    return 0;
176 	}
177     }
178 
179     if (c->b_size < c->chunksize) {
180 	char *tmp;
181 
182 	if ((tmp = realloc(c->buf, c->chunksize)) == NULL)
183 	    return -1;
184 	c->buf = tmp;
185 	c->b_size = c->chunksize;
186     }
187 
188     if ((c->b_len = read(c->fd, c->buf, c->chunksize)) == -1)
189 	return -1;
190     c->chunksize -= c->b_len;
191 
192     if (c->chunksize == 0) {
193 	char endl[2];
194 	read(c->fd, endl, 2);
195     }
196 
197     c->b_pos = 0;
198 
199     return c->b_len;
200 }
201 
202 /*
203  * Read function
204  */
205 static int
206 _http_readfn(void *v, char *buf, int len)
207 {
208     struct cookie *c = (struct cookie *)v;
209     int l, pos;
210 
211     if (c->error)
212 	return -1;
213     if (c->eof)
214 	return 0;
215 
216     for (pos = 0; len > 0; pos += l, len -= l) {
217 	/* empty buffer */
218 	if (!c->buf || c->b_pos == c->b_len)
219 	    if (_http_fillbuf(c) < 1)
220 		break;
221 	l = c->b_len - c->b_pos;
222 	if (len < l)
223 	    l = len;
224 	bcopy(c->buf + c->b_pos, buf + pos, l);
225 	c->b_pos += l;
226     }
227 
228     if (!pos && c->error)
229 	return -1;
230     return pos;
231 }
232 
233 /*
234  * Write function
235  */
236 static int
237 _http_writefn(void *v, const char *buf, int len)
238 {
239     struct cookie *c = (struct cookie *)v;
240 
241     return write(c->fd, buf, len);
242 }
243 
244 /*
245  * Close function
246  */
247 static int
248 _http_closefn(void *v)
249 {
250     struct cookie *c = (struct cookie *)v;
251     int r;
252 
253     r = close(c->fd);
254     if (c->buf)
255 	free(c->buf);
256     free(c);
257     return r;
258 }
259 
260 /*
261  * Wrap a file descriptor up
262  */
263 static FILE *
264 _http_funopen(int fd)
265 {
266     struct cookie *c;
267     FILE *f;
268 
269     if ((c = calloc(1, sizeof *c)) == NULL) {
270 	_fetch_syserr();
271 	return NULL;
272     }
273     c->fd = fd;
274     if (!(f = funopen(c, _http_readfn, _http_writefn, NULL, _http_closefn))) {
275 	_fetch_syserr();
276 	free(c);
277 	return NULL;
278     }
279     return f;
280 }
281 
282 
283 /*****************************************************************************
284  * Helper functions for talking to the server and parsing its replies
285  */
286 
287 /* Header types */
288 typedef enum {
289     hdr_syserror = -2,
290     hdr_error = -1,
291     hdr_end = 0,
292     hdr_unknown = 1,
293     hdr_content_length,
294     hdr_content_range,
295     hdr_last_modified,
296     hdr_location,
297     hdr_transfer_encoding
298 } hdr;
299 
300 /* Names of interesting headers */
301 static struct {
302     hdr		 num;
303     char	*name;
304 } hdr_names[] = {
305     { hdr_content_length,	"Content-Length" },
306     { hdr_content_range,	"Content-Range" },
307     { hdr_last_modified,	"Last-Modified" },
308     { hdr_location,		"Location" },
309     { hdr_transfer_encoding,	"Transfer-Encoding" },
310     { hdr_unknown,		NULL },
311 };
312 
313 static char	*reply_buf;
314 static size_t	 reply_size;
315 static size_t	 reply_length;
316 
317 /*
318  * Send a formatted line; optionally echo to terminal
319  */
320 static int
321 _http_cmd(int fd, char *fmt, ...)
322 {
323     va_list ap;
324     size_t len;
325     char *msg;
326     int r;
327 
328     va_start(ap, fmt);
329     len = vasprintf(&msg, fmt, ap);
330     va_end(ap);
331 
332     if (msg == NULL) {
333 	errno = ENOMEM;
334 	_fetch_syserr();
335 	return -1;
336     }
337 
338     r = _fetch_putln(fd, msg, len);
339     free(msg);
340 
341     if (r == -1) {
342 	_fetch_syserr();
343 	return -1;
344     }
345 
346     return 0;
347 }
348 
349 /*
350  * Get and parse status line
351  */
352 static int
353 _http_get_reply(int fd)
354 {
355     if (_fetch_getln(fd, &reply_buf, &reply_size, &reply_length) == -1)
356 	return -1;
357     /*
358      * A valid status line looks like "HTTP/m.n xyz reason" where m
359      * and n are the major and minor protocol version numbers and xyz
360      * is the reply code.
361      * We grok HTTP 1.0 and 1.1, so m must be 1 and n must be 0 or 1.
362      * We don't care about the reason phrase.
363      */
364     if (strncmp(reply_buf, "HTTP/1.", 7) != 0
365 	|| (reply_buf[7] != '0' && reply_buf[7] != '1') || reply_buf[8] != ' '
366 	|| !isdigit(reply_buf[9])
367 	|| !isdigit(reply_buf[10])
368 	|| !isdigit(reply_buf[11]))
369 	return HTTP_PROTOCOL_ERROR;
370 
371     return ((reply_buf[9] - '0') * 100
372 	    + (reply_buf[10] - '0') * 10
373 	    + (reply_buf[11] - '0'));
374 }
375 
376 /*
377  * Check a header; if the type matches the given string, return a
378  * pointer to the beginning of the value.
379  */
380 static char *
381 _http_match(char *str, char *hdr)
382 {
383     while (*str && *hdr && tolower(*str++) == tolower(*hdr++))
384 	/* nothing */;
385     if (*str || *hdr != ':')
386 	return NULL;
387     while (*hdr && isspace(*++hdr))
388 	/* nothing */;
389     return hdr;
390 }
391 
392 /*
393  * Get the next header and return the appropriate symbolic code.
394  */
395 static hdr
396 _http_next_header(int fd, char **p)
397 {
398     int i;
399 
400     if (_fetch_getln(fd, &reply_buf, &reply_size, &reply_length) == -1)
401 	return hdr_syserror;
402     while (reply_length && isspace(reply_buf[reply_length-1]))
403 	reply_length--;
404     reply_buf[reply_length] = 0;
405     if (reply_length == 0)
406 	return hdr_end;
407     /*
408      * We could check for malformed headers but we don't really care.
409      * A valid header starts with a token immediately followed by a
410      * colon; a token is any sequence of non-control, non-whitespace
411      * characters except "()<>@,;:\\\"{}".
412      */
413     for (i = 0; hdr_names[i].num != hdr_unknown; i++)
414 	if ((*p = _http_match(hdr_names[i].name, reply_buf)) != NULL)
415 	    return hdr_names[i].num;
416     return hdr_unknown;
417 }
418 
419 /*
420  * Parse a last-modified header
421  */
422 static time_t
423 _http_parse_mtime(char *p)
424 {
425     char locale[64];
426     struct tm tm;
427 
428     strncpy(locale, setlocale(LC_TIME, NULL), sizeof locale);
429     setlocale(LC_TIME, "C");
430     strptime(p, "%a, %d %b %Y %H:%M:%S GMT", &tm);
431     /* XXX should add support for date-2 and date-3 */
432     setlocale(LC_TIME, locale);
433     DEBUG(fprintf(stderr, "last modified: [\033[1m%04d-%02d-%02d "
434 		  "%02d:%02d:%02d\033[m]\n",
435 		  tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
436 		  tm.tm_hour, tm.tm_min, tm.tm_sec));
437     return timegm(&tm);
438 }
439 
440 /*
441  * Parse a content-length header
442  */
443 static off_t
444 _http_parse_length(char *p)
445 {
446     off_t len;
447 
448     for (len = 0; *p && isdigit(*p); ++p)
449 	len = len * 10 + (*p - '0');
450     DEBUG(fprintf(stderr, "content length: [\033[1m%lld\033[m]\n", len));
451     return len;
452 }
453 
454 /*
455  * Parse a content-range header
456  */
457 static off_t
458 _http_parse_range(char *p)
459 {
460     off_t off;
461 
462     if (strncasecmp(p, "bytes ", 6) != 0)
463 	return -1;
464     for (p += 6, off = 0; *p && isdigit(*p); ++p)
465 	off = off * 10 + *p - '0';
466     if (*p != '-')
467 	return -1;
468     DEBUG(fprintf(stderr, "content range: [\033[1m%lld-\033[m]\n", off));
469     return off;
470 }
471 
472 
473 /*****************************************************************************
474  * Helper functions for authorization
475  */
476 
477 /*
478  * Base64 encoding
479  */
480 static char *
481 _http_base64(char *src)
482 {
483     static const char base64[] =
484 	"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
485 	"abcdefghijklmnopqrstuvwxyz"
486 	"0123456789+/";
487     char *str, *dst;
488     size_t l;
489     int t, r;
490 
491     l = strlen(src);
492     if ((str = malloc(((l + 2) / 3) * 4)) == NULL)
493 	return NULL;
494     dst = str;
495     r = 0;
496 
497     while (l >= 3) {
498 	t = (src[0] << 16) | (src[1] << 8) | src[2];
499 	dst[0] = base64[(t >> 18) & 0x3f];
500 	dst[1] = base64[(t >> 12) & 0x3f];
501 	dst[2] = base64[(t >> 6) & 0x3f];
502 	dst[3] = base64[(t >> 0) & 0x3f];
503 	src += 3; l -= 3;
504 	dst += 4; r += 4;
505     }
506 
507     switch (l) {
508     case 2:
509 	t = (src[0] << 16) | (src[1] << 8);
510 	dst[0] = base64[(t >> 18) & 0x3f];
511 	dst[1] = base64[(t >> 12) & 0x3f];
512 	dst[2] = base64[(t >> 6) & 0x3f];
513 	dst[3] = '=';
514 	dst += 4;
515 	r += 4;
516 	break;
517     case 1:
518 	t = src[0] << 16;
519 	dst[0] = base64[(t >> 18) & 0x3f];
520 	dst[1] = base64[(t >> 12) & 0x3f];
521 	dst[2] = dst[3] = '=';
522 	dst += 4;
523 	r += 4;
524 	break;
525     case 0:
526 	break;
527     }
528 
529     *dst = 0;
530     return str;
531 }
532 
533 /*
534  * Encode username and password
535  */
536 static int
537 _http_basic_auth(int fd, char *hdr, char *usr, char *pwd)
538 {
539     char *upw, *auth;
540     int r;
541 
542     if (asprintf(&upw, "%s:%s", usr, pwd) == -1)
543 	return -1;
544     auth = _http_base64(upw);
545     free(upw);
546     if (auth == NULL)
547 	return -1;
548     r = _http_cmd(fd, "%s: Basic %s", hdr, auth);
549     free(auth);
550     return r;
551 }
552 
553 /*
554  * Send an authorization header
555  */
556 static int
557 _http_authorize(int fd, char *hdr, char *p)
558 {
559     /* basic authorization */
560     if (strncasecmp(p, "basic:", 6) == 0) {
561 	char *user, *pwd, *str;
562 	int r;
563 
564 	/* skip realm */
565 	for (p += 6; *p && *p != ':'; ++p)
566 	    /* nothing */ ;
567 	if (!*p || strchr(++p, ':') == NULL)
568 	    return -1;
569 	if ((str = strdup(p)) == NULL)
570 	    return -1; /* XXX */
571 	user = str;
572 	pwd = strchr(str, ':');
573 	*pwd++ = '\0';
574 	r = _http_basic_auth(fd, hdr, user, pwd);
575 	free(str);
576 	return r;
577     }
578     return -1;
579 }
580 
581 
582 /*****************************************************************************
583  * Helper functions for connecting to a server or proxy
584  */
585 
586 /*
587  * Connect to the specified HTTP proxy server.
588  */
589 static int
590 _http_proxy_connect(char *proxy, int af, int verbose)
591 {
592     char *hostname, *p;
593     int fd, port;
594 
595     /* get hostname */
596     hostname = NULL;
597 #ifdef INET6
598     /* host part can be an IPv6 address enclosed in square brackets */
599     if (*proxy == '[') {
600 	if ((p = strchr(proxy, ']')) == NULL) {
601 	    /* no terminating bracket */
602 	    /* XXX should set an error code */
603 	    goto ouch;
604 	}
605 	if (p[1] != '\0' && p[1] != ':') {
606 	    /* garbage after address */
607 	    /* XXX should set an error code */
608 	    goto ouch;
609 	}
610 	if ((hostname = malloc(p - proxy)) == NULL) {
611 	    errno = ENOMEM;
612 	    _fetch_syserr();
613 	    goto ouch;
614 	}
615 	strncpy(hostname, proxy + 1, p - proxy - 1);
616 	hostname[p - proxy - 1] = '\0';
617 	++p;
618     } else {
619 #endif /* INET6 */
620 	if ((p = strchr(proxy, ':')) == NULL)
621 	    p = strchr(proxy, '\0');
622 	if ((hostname = malloc(p - proxy + 1)) == NULL) {
623 	    errno = ENOMEM;
624 	    _fetch_syserr();
625 	    goto ouch;
626 	}
627 	strncpy(hostname, proxy, p - proxy);
628 	hostname[p - proxy] = '\0';
629 #ifdef INET6
630     }
631 #endif /* INET6 */
632     DEBUG(fprintf(stderr, "proxy name: [%s]\n", hostname));
633 
634     /* get port number */
635     port = 0;
636     if (*p == ':') {
637 	++p;
638 	if (strspn(p, "0123456789") != strlen(p) || strlen(p) > 5) {
639 	    /* port number is non-numeric or too long */
640 	    /* XXX should set an error code */
641 	    goto ouch;
642 	}
643 	port = atoi(p);
644 	if (port < 1 || port > 65535) {
645 	    /* port number is out of range */
646 	    /* XXX should set an error code */
647 	    goto ouch;
648 	}
649     }
650 
651     if (!port) {
652 #if 0
653 	/*
654 	 * commented out, since there is currently no service name
655 	 * for HTTP proxies
656 	 */
657 	struct servent *se;
658 
659 	if ((se = getservbyname("xxxx", "tcp")) != NULL)
660 	    port = ntohs(se->s_port);
661 	else
662 #endif
663 	    port = 3128;
664     }
665     DEBUG(fprintf(stderr, "proxy port: %d\n", port));
666 
667     /* connect */
668     if ((fd = _fetch_connect(hostname, port, af, verbose)) == -1)
669 	_fetch_syserr();
670     return fd;
671 
672  ouch:
673     if (hostname)
674 	free(hostname);
675     return -1;
676 }
677 
678 /*
679  * Connect to the correct HTTP server or proxy.
680  */
681 static int
682 _http_connect(struct url *URL, int *proxy, char *flags)
683 {
684     int direct, verbose;
685     int af, fd;
686     char *p;
687 
688 #ifdef INET6
689     af = AF_UNSPEC;
690 #else
691     af = AF_INET;
692 #endif
693 
694     direct = (flags && strchr(flags, 'd'));
695     verbose = (flags && strchr(flags, 'v'));
696     if (flags && strchr(flags, '4'))
697 	af = AF_INET;
698     else if (flags && strchr(flags, '6'))
699 	af = AF_INET6;
700 
701     /* check port */
702     if (!URL->port) {
703 	struct servent *se;
704 
705 	/* Scheme can be ftp if we're using a proxy */
706 	if (strcasecmp(URL->scheme, "ftp") == 0)
707 	    if ((se = getservbyname("ftp", "tcp")) != NULL)
708 		URL->port = ntohs(se->s_port);
709 	    else
710 		URL->port = 21;
711 	else
712 	    if ((se = getservbyname("http", "tcp")) != NULL)
713 		URL->port = ntohs(se->s_port);
714 	    else
715 		URL->port = 80;
716     }
717 
718     if (!direct && (p = getenv("HTTP_PROXY")) != NULL) {
719 	/* attempt to connect to proxy server */
720 	if ((fd = _http_proxy_connect(p, af, verbose)) == -1)
721 	    return -1;
722 	*proxy = 1;
723     } else {
724 	/* if no proxy is configured, try direct */
725 	if (strcasecmp(URL->scheme, "ftp") == 0) {
726 	    /* can't talk http to an ftp server */
727 	    /* XXX should set an error code */
728 	    return -1;
729 	}
730 	if ((fd = _fetch_connect(URL->host, URL->port, af, verbose)) == -1)
731 	    /* _fetch_connect() has already set an error code */
732 	    return -1;
733 	*proxy = 0;
734     }
735 
736     return fd;
737 }
738 
739 
740 /*****************************************************************************
741  * Core
742  */
743 
744 /*
745  * Send a request and process the reply
746  */
747 static FILE *
748 _http_request(struct url *URL, char *op, struct url_stat *us, char *flags)
749 {
750     struct url *url, *new;
751     int chunked, need_auth, noredirect, proxy, verbose;
752     int code, fd, i, n;
753     off_t offset;
754     char *p;
755     FILE *f;
756     hdr h;
757     char *host;
758 #ifdef INET6
759     char hbuf[MAXHOSTNAMELEN + 1];
760 #endif
761 
762     noredirect = (flags && strchr(flags, 'A'));
763     verbose = (flags && strchr(flags, 'v'));
764 
765     n = noredirect ? 1 : MAX_REDIRECT;
766 
767     /* just to appease compiler warnings */
768     code = HTTP_PROTOCOL_ERROR;
769     chunked = 0;
770     offset = 0;
771     fd = -1;
772 
773     for (url = URL, i = 0; i < n; ++i) {
774 	new = NULL;
775 	if (us) {
776 	    us->size = -1;
777 	    us->atime = us->mtime = 0;
778 	}
779 	chunked = 0;
780 	need_auth = 0;
781 	offset = 0;
782     retry:
783 	/* connect to server or proxy */
784 	if ((fd = _http_connect(url, &proxy, flags)) == -1)
785 	    goto ouch;
786 
787 	host = url->host;
788 #ifdef INET6
789 	if (strchr(url->host, ':')) {
790 	    snprintf(hbuf, sizeof(hbuf), "[%s]", url->host);
791 	    host = hbuf;
792 	}
793 #endif
794 
795 	/* send request */
796 	if (verbose)
797 	    _fetch_info("requesting %s://%s:%d%s",
798 			url->scheme, host, url->port, url->doc);
799 	if (proxy) {
800 	    _http_cmd(fd, "%s %s://%s:%d%s HTTP/1.1",
801 		      op, url->scheme, host, url->port, url->doc);
802 	} else {
803 	    _http_cmd(fd, "%s %s HTTP/1.1",
804 		      op, url->doc);
805 	}
806 
807 	/* proxy authorization */
808 	if (proxy && (p = getenv("HTTP_PROXY_AUTH")) != NULL)
809 	    _http_authorize(fd, "Proxy-Authorization", p);
810 
811 	/* server authorization */
812 	if (need_auth) {
813 	    if (*url->user || *url->pwd)
814 		_http_basic_auth(fd, "Authorization",
815 				 url->user ? url->user : "",
816 				 url->pwd ? url->pwd : "");
817 	    else if ((p = getenv("HTTP_AUTH")) != NULL)
818 		_http_authorize(fd, "Authorization", p);
819 	    else {
820 		_http_seterr(HTTP_NEED_AUTH);
821 		goto ouch;
822 	    }
823 	}
824 
825 	/* other headers */
826 	_http_cmd(fd, "Host: %s:%d", host, url->port);
827 	_http_cmd(fd, "User-Agent: %s " _LIBFETCH_VER, __progname);
828 	if (url->offset)
829 	    _http_cmd(fd, "Range: bytes=%lld-", url->offset);
830 	_http_cmd(fd, "Connection: close");
831 	_http_cmd(fd, "");
832 
833 	/* get reply */
834 	switch ((code = _http_get_reply(fd))) {
835 	case HTTP_OK:
836 	case HTTP_PARTIAL:
837 	    /* fine */
838 	    break;
839 	case HTTP_MOVED_PERM:
840 	case HTTP_MOVED_TEMP:
841 	    /*
842 	     * Not so fine, but we still have to read the headers to
843 	     * get the new location.
844 	     */
845 	    break;
846 	case HTTP_NEED_AUTH:
847 	    if (need_auth) {
848 		/*
849 		 * We already sent out authorization code, so there's
850 		 * nothing more we can do.
851 		 */
852 		_http_seterr(code);
853 		goto ouch;
854 	    }
855 	    /* try again, but send the password this time */
856 	    if (verbose)
857 		_fetch_info("server requires authorization");
858 	    need_auth = 1;
859 	    close(fd);
860 	    goto retry;
861 	case HTTP_NEED_PROXY_AUTH:
862 	    /*
863 	     * If we're talking to a proxy, we already sent our proxy
864 	     * authorization code, so there's nothing more we can do.
865 	     */
866 	    _http_seterr(code);
867 	    goto ouch;
868 	case HTTP_PROTOCOL_ERROR:
869 	    /* fall through */
870 	case -1:
871 	    _fetch_syserr();
872 	    goto ouch;
873 	default:
874 	    _http_seterr(code);
875 	    goto ouch;
876 	}
877 
878 	/* get headers */
879 	do {
880 	    switch ((h = _http_next_header(fd, &p))) {
881 	    case hdr_syserror:
882 		_fetch_syserr();
883 		goto ouch;
884 	    case hdr_error:
885 		_http_seterr(HTTP_PROTOCOL_ERROR);
886 		goto ouch;
887 	    case hdr_content_length:
888 		if (us)
889 		    us->size = _http_parse_length(p);
890 		break;
891 	    case hdr_content_range:
892 		offset = _http_parse_range(p);
893 		break;
894 	    case hdr_last_modified:
895 		if (us)
896 		    us->atime = us->mtime = _http_parse_mtime(p);
897 		break;
898 	    case hdr_location:
899 		if (!HTTP_REDIRECT(code))
900 		    break;
901 		if (new)
902 		    free(new);
903 		if (verbose)
904 		    _fetch_info("%d redirect to %s", code, p);
905 		if (*p == '/')
906 		    /* absolute path */
907 		    new = fetchMakeURL(url->scheme, url->host, url->port, p,
908 				       url->user, url->pwd);
909 		else
910 		    new = fetchParseURL(p);
911 		if (new == NULL) {
912 		    /* XXX should set an error code */
913 		    DEBUG(fprintf(stderr, "failed to parse new URL\n"));
914 		    goto ouch;
915 		}
916 		if (!*new->user && !*new->pwd) {
917 		    strcpy(new->user, url->user);
918 		    strcpy(new->pwd, url->pwd);
919 		}
920 		new->offset = url->offset;
921 		new->length = url->length;
922 		break;
923 	    case hdr_transfer_encoding:
924 		/* XXX weak test*/
925 		chunked = (strcasecmp(p, "chunked") == 0);
926 		break;
927 	    case hdr_end:
928 		/* fall through */
929 	    case hdr_unknown:
930 		/* ignore */
931 		break;
932 	    }
933 	} while (h > hdr_end);
934 
935 	/* we either have a hit, or a redirect with no Location: header */
936 	if (code == HTTP_OK || code == HTTP_PARTIAL || !new)
937 	    break;
938 
939 	/* we have a redirect */
940 	close(fd);
941 	fd = -1;
942 	if (url != URL)
943 	    fetchFreeURL(url);
944 	url = new;
945     }
946 
947     /* no success */
948     if (fd == -1) {
949 	_http_seterr(code);
950 	goto ouch;
951     }
952 
953     /* too far? */
954     if (offset > url->offset) {
955 	_http_seterr(HTTP_PROTOCOL_ERROR);
956 	goto ouch;
957     }
958 
959     /* report back real offset */
960     URL->offset = offset;
961 
962     /* wrap it up in a FILE */
963     if ((f = chunked ? _http_funopen(fd) : fdopen(fd, "r")) == NULL) {
964 	_fetch_syserr();
965 	goto ouch;
966     }
967 
968     if (url != URL)
969 	fetchFreeURL(url);
970 
971     return f;
972 
973  ouch:
974     if (url != URL)
975 	fetchFreeURL(url);
976     if (fd != -1)
977 	close(fd);
978     return NULL;
979 }
980 
981 
982 /*****************************************************************************
983  * Entry points
984  */
985 
986 /*
987  * Retrieve and stat a file by HTTP
988  */
989 FILE *
990 fetchXGetHTTP(struct url *URL, struct url_stat *us, char *flags)
991 {
992     return _http_request(URL, "GET", us, flags);
993 }
994 
995 /*
996  * Retrieve a file by HTTP
997  */
998 FILE *
999 fetchGetHTTP(struct url *URL, char *flags)
1000 {
1001     return fetchXGetHTTP(URL, NULL, flags);
1002 }
1003 
1004 /*
1005  * Store a file by HTTP
1006  */
1007 FILE *
1008 fetchPutHTTP(struct url *URL, char *flags)
1009 {
1010     warnx("fetchPutHTTP(): not implemented");
1011     return NULL;
1012 }
1013 
1014 /*
1015  * Get an HTTP document's metadata
1016  */
1017 int
1018 fetchStatHTTP(struct url *URL, struct url_stat *us, char *flags)
1019 {
1020     FILE *f;
1021 
1022     if ((f = _http_request(URL, "HEAD", us, flags)) == NULL)
1023 	return -1;
1024     fclose(f);
1025     return 0;
1026 }
1027 
1028 /*
1029  * List a directory
1030  */
1031 struct url_ent *
1032 fetchListHTTP(struct url *url, char *flags)
1033 {
1034     warnx("fetchListHTTP(): not implemented");
1035     return NULL;
1036 }
1037