xref: /freebsd/lib/libfetch/http.c (revision c1462236787ec09d00d5e2d222edc3e34bce1e69)
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 int
423 _http_parse_mtime(char *p, time_t *mtime)
424 {
425     char locale[64], *r;
426     struct tm tm;
427 
428     strncpy(locale, setlocale(LC_TIME, NULL), sizeof locale);
429     setlocale(LC_TIME, "C");
430     r = 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     if (r == NULL)
434 	return -1;
435     DEBUG(fprintf(stderr, "last modified: [\033[1m%04d-%02d-%02d "
436 		  "%02d:%02d:%02d\033[m]\n",
437 		  tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
438 		  tm.tm_hour, tm.tm_min, tm.tm_sec));
439     *mtime = timegm(&tm);
440     return 0;
441 }
442 
443 /*
444  * Parse a content-length header
445  */
446 static int
447 _http_parse_length(char *p, size_t *length)
448 {
449     size_t len;
450 
451     for (len = 0; *p && isdigit(*p); ++p)
452 	len = len * 10 + (*p - '0');
453     DEBUG(fprintf(stderr, "content length: [\033[1m%d\033[m]\n", len));
454     *length = len;
455     return 0;
456 }
457 
458 /*
459  * Parse a content-range header
460  */
461 static int
462 _http_parse_range(char *p, off_t *offset, size_t *length, size_t *size)
463 {
464     int first, last, len;
465 
466     if (strncasecmp(p, "bytes ", 6) != 0)
467 	return -1;
468     for (first = 0, p += 6; *p && isdigit(*p); ++p)
469 	first = first * 10 + *p - '0';
470     if (*p != '-')
471 	return -1;
472     for (last = 0, ++p; *p && isdigit(*p); ++p)
473 	last = last * 10 + *p - '0';
474     if (first > last || *p != '/')
475 	return -1;
476     for (len = 0, ++p; *p && isdigit(*p); ++p)
477 	len = len * 10 + *p - '0';
478     if (len < last - first + 1)
479 	return -1;
480     DEBUG(fprintf(stderr, "content range: [\033[1m%d-%d/%d\033[m]\n",
481 		  first, last, len));
482     *offset = first;
483     *length = last - first + 1;
484     *size = len;
485     return 0;
486 }
487 
488 
489 /*****************************************************************************
490  * Helper functions for authorization
491  */
492 
493 /*
494  * Base64 encoding
495  */
496 static char *
497 _http_base64(char *src)
498 {
499     static const char base64[] =
500 	"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
501 	"abcdefghijklmnopqrstuvwxyz"
502 	"0123456789+/";
503     char *str, *dst;
504     size_t l;
505     int t, r;
506 
507     l = strlen(src);
508     if ((str = malloc(((l + 2) / 3) * 4)) == NULL)
509 	return NULL;
510     dst = str;
511     r = 0;
512 
513     while (l >= 3) {
514 	t = (src[0] << 16) | (src[1] << 8) | src[2];
515 	dst[0] = base64[(t >> 18) & 0x3f];
516 	dst[1] = base64[(t >> 12) & 0x3f];
517 	dst[2] = base64[(t >> 6) & 0x3f];
518 	dst[3] = base64[(t >> 0) & 0x3f];
519 	src += 3; l -= 3;
520 	dst += 4; r += 4;
521     }
522 
523     switch (l) {
524     case 2:
525 	t = (src[0] << 16) | (src[1] << 8);
526 	dst[0] = base64[(t >> 18) & 0x3f];
527 	dst[1] = base64[(t >> 12) & 0x3f];
528 	dst[2] = base64[(t >> 6) & 0x3f];
529 	dst[3] = '=';
530 	dst += 4;
531 	r += 4;
532 	break;
533     case 1:
534 	t = src[0] << 16;
535 	dst[0] = base64[(t >> 18) & 0x3f];
536 	dst[1] = base64[(t >> 12) & 0x3f];
537 	dst[2] = dst[3] = '=';
538 	dst += 4;
539 	r += 4;
540 	break;
541     case 0:
542 	break;
543     }
544 
545     *dst = 0;
546     return str;
547 }
548 
549 /*
550  * Encode username and password
551  */
552 static int
553 _http_basic_auth(int fd, char *hdr, char *usr, char *pwd)
554 {
555     char *upw, *auth;
556     int r;
557 
558     if (asprintf(&upw, "%s:%s", usr, pwd) == -1)
559 	return -1;
560     auth = _http_base64(upw);
561     free(upw);
562     if (auth == NULL)
563 	return -1;
564     r = _http_cmd(fd, "%s: Basic %s", hdr, auth);
565     free(auth);
566     return r;
567 }
568 
569 /*
570  * Send an authorization header
571  */
572 static int
573 _http_authorize(int fd, char *hdr, char *p)
574 {
575     /* basic authorization */
576     if (strncasecmp(p, "basic:", 6) == 0) {
577 	char *user, *pwd, *str;
578 	int r;
579 
580 	/* skip realm */
581 	for (p += 6; *p && *p != ':'; ++p)
582 	    /* nothing */ ;
583 	if (!*p || strchr(++p, ':') == NULL)
584 	    return -1;
585 	if ((str = strdup(p)) == NULL)
586 	    return -1; /* XXX */
587 	user = str;
588 	pwd = strchr(str, ':');
589 	*pwd++ = '\0';
590 	r = _http_basic_auth(fd, hdr, user, pwd);
591 	free(str);
592 	return r;
593     }
594     return -1;
595 }
596 
597 
598 /*****************************************************************************
599  * Helper functions for connecting to a server or proxy
600  */
601 
602 /*
603  * Connect to the specified HTTP proxy server.
604  */
605 static int
606 _http_proxy_connect(char *proxy, int af, int verbose)
607 {
608     char *hostname, *p;
609     int fd, port;
610 
611     /* get hostname */
612     hostname = NULL;
613 #ifdef INET6
614     /* host part can be an IPv6 address enclosed in square brackets */
615     if (*proxy == '[') {
616 	if ((p = strchr(proxy, ']')) == NULL) {
617 	    /* no terminating bracket */
618 	    /* XXX should set an error code */
619 	    goto ouch;
620 	}
621 	if (p[1] != '\0' && p[1] != ':') {
622 	    /* garbage after address */
623 	    /* XXX should set an error code */
624 	    goto ouch;
625 	}
626 	if ((hostname = malloc(p - proxy)) == NULL) {
627 	    errno = ENOMEM;
628 	    _fetch_syserr();
629 	    goto ouch;
630 	}
631 	strncpy(hostname, proxy + 1, p - proxy - 1);
632 	hostname[p - proxy - 1] = '\0';
633 	++p;
634     } else {
635 #endif /* INET6 */
636 	if ((p = strchr(proxy, ':')) == NULL)
637 	    p = strchr(proxy, '\0');
638 	if ((hostname = malloc(p - proxy + 1)) == NULL) {
639 	    errno = ENOMEM;
640 	    _fetch_syserr();
641 	    goto ouch;
642 	}
643 	strncpy(hostname, proxy, p - proxy);
644 	hostname[p - proxy] = '\0';
645 #ifdef INET6
646     }
647 #endif /* INET6 */
648     DEBUG(fprintf(stderr, "proxy name: [%s]\n", hostname));
649 
650     /* get port number */
651     port = 0;
652     if (*p == ':') {
653 	++p;
654 	if (strspn(p, "0123456789") != strlen(p) || strlen(p) > 5) {
655 	    /* port number is non-numeric or too long */
656 	    /* XXX should set an error code */
657 	    goto ouch;
658 	}
659 	port = atoi(p);
660 	if (port < 1 || port > 65535) {
661 	    /* port number is out of range */
662 	    /* XXX should set an error code */
663 	    goto ouch;
664 	}
665     }
666 
667     if (!port) {
668 #if 0
669 	/*
670 	 * commented out, since there is currently no service name
671 	 * for HTTP proxies
672 	 */
673 	struct servent *se;
674 
675 	if ((se = getservbyname("xxxx", "tcp")) != NULL)
676 	    port = ntohs(se->s_port);
677 	else
678 #endif
679 	    port = 3128;
680     }
681     DEBUG(fprintf(stderr, "proxy port: %d\n", port));
682 
683     /* connect */
684     if ((fd = _fetch_connect(hostname, port, af, verbose)) == -1)
685 	_fetch_syserr();
686     return fd;
687 
688  ouch:
689     if (hostname)
690 	free(hostname);
691     return -1;
692 }
693 
694 /*
695  * Connect to the correct HTTP server or proxy.
696  */
697 static int
698 _http_connect(struct url *URL, int *proxy, char *flags)
699 {
700     int direct, verbose;
701     int af, fd;
702     char *p;
703 
704 #ifdef INET6
705     af = AF_UNSPEC;
706 #else
707     af = AF_INET;
708 #endif
709 
710     direct = (flags && strchr(flags, 'd'));
711     verbose = (flags && strchr(flags, 'v'));
712     if (flags && strchr(flags, '4'))
713 	af = AF_INET;
714     else if (flags && strchr(flags, '6'))
715 	af = AF_INET6;
716 
717     /* check port */
718     if (!URL->port) {
719 	struct servent *se;
720 
721 	/* Scheme can be ftp if we're using a proxy */
722 	if (strcasecmp(URL->scheme, "ftp") == 0)
723 	    if ((se = getservbyname("ftp", "tcp")) != NULL)
724 		URL->port = ntohs(se->s_port);
725 	    else
726 		URL->port = 21;
727 	else
728 	    if ((se = getservbyname("http", "tcp")) != NULL)
729 		URL->port = ntohs(se->s_port);
730 	    else
731 		URL->port = 80;
732     }
733 
734     if (!direct && (p = getenv("HTTP_PROXY")) != NULL && *p != '\0') {
735 	/* attempt to connect to proxy server */
736 	if ((fd = _http_proxy_connect(p, af, verbose)) == -1)
737 	    return -1;
738 	*proxy = 1;
739     } else {
740 	/* if no proxy is configured, try direct */
741 	if (strcasecmp(URL->scheme, "ftp") == 0) {
742 	    /* can't talk http to an ftp server */
743 	    /* XXX should set an error code */
744 	    return -1;
745 	}
746 	if ((fd = _fetch_connect(URL->host, URL->port, af, verbose)) == -1)
747 	    /* _fetch_connect() has already set an error code */
748 	    return -1;
749 	*proxy = 0;
750     }
751 
752     return fd;
753 }
754 
755 
756 /*****************************************************************************
757  * Core
758  */
759 
760 /*
761  * Send a request and process the reply
762  */
763 static FILE *
764 _http_request(struct url *URL, char *op, struct url_stat *us, char *flags)
765 {
766     struct url *url, *new;
767     int chunked, need_auth, noredirect, proxy, verbose;
768     int code, fd, i, n;
769     off_t offset;
770     size_t clength, length, size;
771     time_t mtime;
772     char *p;
773     FILE *f;
774     hdr h;
775     char *host;
776 #ifdef INET6
777     char hbuf[MAXHOSTNAMELEN + 1];
778 #endif
779 
780     noredirect = (flags && strchr(flags, 'A'));
781     verbose = (flags && strchr(flags, 'v'));
782 
783     /* try the provided URL first */
784     url = URL;
785 
786     /* if the A flag is set, we only get one try */
787     n = noredirect ? 1 : MAX_REDIRECT;
788     i = 0;
789 
790     do {
791 	new = NULL;
792 	chunked = 0;
793 	need_auth = 0;
794 	offset = 0;
795 	clength = -1;
796 	length = -1;
797 	size = -1;
798 	mtime = 0;
799     retry:
800 	/* connect to server or proxy */
801 	if ((fd = _http_connect(url, &proxy, flags)) == -1)
802 	    goto ouch;
803 
804 	host = url->host;
805 #ifdef INET6
806 	if (strchr(url->host, ':')) {
807 	    snprintf(hbuf, sizeof(hbuf), "[%s]", url->host);
808 	    host = hbuf;
809 	}
810 #endif
811 
812 	/* send request */
813 	if (verbose)
814 	    _fetch_info("requesting %s://%s:%d%s",
815 			url->scheme, host, url->port, url->doc);
816 	if (proxy) {
817 	    _http_cmd(fd, "%s %s://%s:%d%s HTTP/1.1",
818 		      op, url->scheme, host, url->port, url->doc);
819 	} else {
820 	    _http_cmd(fd, "%s %s HTTP/1.1",
821 		      op, url->doc);
822 	}
823 
824 	/* proxy authorization */
825 	if (proxy && (p = getenv("HTTP_PROXY_AUTH")) != NULL && *p != '\0')
826 	    _http_authorize(fd, "Proxy-Authorization", p);
827 
828 	/* server authorization */
829 	if (need_auth) {
830 	    if (*url->user || *url->pwd)
831 		_http_basic_auth(fd, "Authorization",
832 				 url->user ? url->user : "",
833 				 url->pwd ? url->pwd : "");
834 	    else if ((p = getenv("HTTP_AUTH")) != NULL && *p != '\0')
835 		_http_authorize(fd, "Authorization", p);
836 	    else {
837 		_http_seterr(HTTP_NEED_AUTH);
838 		goto ouch;
839 	    }
840 	}
841 
842 	/* other headers */
843 	_http_cmd(fd, "Host: %s:%d", host, url->port);
844 	_http_cmd(fd, "User-Agent: %s " _LIBFETCH_VER, __progname);
845 	if (url->offset)
846 	    _http_cmd(fd, "Range: bytes=%lld-", url->offset);
847 	_http_cmd(fd, "Connection: close");
848 	_http_cmd(fd, "");
849 
850 	/* get reply */
851 	switch ((code = _http_get_reply(fd))) {
852 	case HTTP_OK:
853 	case HTTP_PARTIAL:
854 	    /* fine */
855 	    break;
856 	case HTTP_MOVED_PERM:
857 	case HTTP_MOVED_TEMP:
858 	    /*
859 	     * Not so fine, but we still have to read the headers to
860 	     * get the new location.
861 	     */
862 	    break;
863 	case HTTP_NEED_AUTH:
864 	    if (need_auth) {
865 		/*
866 		 * We already sent out authorization code, so there's
867 		 * nothing more we can do.
868 		 */
869 		_http_seterr(code);
870 		goto ouch;
871 	    }
872 	    /* try again, but send the password this time */
873 	    if (verbose)
874 		_fetch_info("server requires authorization");
875 	    need_auth = 1;
876 	    close(fd);
877 	    goto retry;
878 	case HTTP_NEED_PROXY_AUTH:
879 	    /*
880 	     * If we're talking to a proxy, we already sent our proxy
881 	     * authorization code, so there's nothing more we can do.
882 	     */
883 	    _http_seterr(code);
884 	    goto ouch;
885 	case HTTP_PROTOCOL_ERROR:
886 	    /* fall through */
887 	case -1:
888 	    _fetch_syserr();
889 	    goto ouch;
890 	default:
891 	    _http_seterr(code);
892 	    goto ouch;
893 	}
894 
895 	/* get headers */
896 	do {
897 	    switch ((h = _http_next_header(fd, &p))) {
898 	    case hdr_syserror:
899 		_fetch_syserr();
900 		goto ouch;
901 	    case hdr_error:
902 		_http_seterr(HTTP_PROTOCOL_ERROR);
903 		goto ouch;
904 	    case hdr_content_length:
905 		_http_parse_length(p, &clength);
906 		break;
907 	    case hdr_content_range:
908 		_http_parse_range(p, &offset, &length, &size);
909 		break;
910 	    case hdr_last_modified:
911 		_http_parse_mtime(p, &mtime);
912 		break;
913 	    case hdr_location:
914 		if (!HTTP_REDIRECT(code))
915 		    break;
916 		if (new)
917 		    free(new);
918 		if (verbose)
919 		    _fetch_info("%d redirect to %s", code, p);
920 		if (*p == '/')
921 		    /* absolute path */
922 		    new = fetchMakeURL(url->scheme, url->host, url->port, p,
923 				       url->user, url->pwd);
924 		else
925 		    new = fetchParseURL(p);
926 		if (new == NULL) {
927 		    /* XXX should set an error code */
928 		    DEBUG(fprintf(stderr, "failed to parse new URL\n"));
929 		    goto ouch;
930 		}
931 		if (!*new->user && !*new->pwd) {
932 		    strcpy(new->user, url->user);
933 		    strcpy(new->pwd, url->pwd);
934 		}
935 		new->offset = url->offset;
936 		new->length = url->length;
937 		break;
938 	    case hdr_transfer_encoding:
939 		/* XXX weak test*/
940 		chunked = (strcasecmp(p, "chunked") == 0);
941 		break;
942 	    case hdr_end:
943 		/* fall through */
944 	    case hdr_unknown:
945 		/* ignore */
946 		break;
947 	    }
948 	} while (h > hdr_end);
949 
950 	/* we either have a hit, or a redirect with no Location: header */
951 	if (code == HTTP_OK || code == HTTP_PARTIAL || !new)
952 	    break;
953 
954 	/* we have a redirect */
955 	close(fd);
956 	fd = -1;
957 	if (url != URL)
958 	    fetchFreeURL(url);
959 	url = new;
960     } while (++i < n);
961 
962     /* no success */
963     if (fd == -1) {
964 	_http_seterr(code);
965 	goto ouch;
966     }
967 
968     DEBUG(fprintf(stderr, "offset: %lld, length: %d, size: %d, clength: %d\n",
969 		  offset, length, size, clength));
970 
971     /* check for inconsistencies */
972     if (clength != -1 && length != -1 && clength != length) {
973 	_http_seterr(HTTP_PROTOCOL_ERROR);
974 	goto ouch;
975     }
976     if (clength == -1)
977 	clength = length;
978     if (clength != -1)
979 	length = offset + clength;
980     if (length != -1 && size != -1 && length != size) {
981 	_http_seterr(HTTP_PROTOCOL_ERROR);
982 	goto ouch;
983     }
984     if (size == -1)
985 	size = length;
986 
987     /* fill in stats */
988     if (us) {
989 	us->size = size;
990 	us->atime = us->mtime = mtime;
991     }
992 
993     /* too far? */
994     if (offset > URL->offset) {
995 	_http_seterr(HTTP_PROTOCOL_ERROR);
996 	goto ouch;
997     }
998 
999     /* report back real offset and size */
1000     URL->offset = offset;
1001     URL->length = clength;
1002 
1003     /* wrap it up in a FILE */
1004     if ((f = chunked ? _http_funopen(fd) : fdopen(fd, "r")) == NULL) {
1005 	_fetch_syserr();
1006 	goto ouch;
1007     }
1008 
1009     if (url != URL)
1010 	fetchFreeURL(url);
1011 
1012     return f;
1013 
1014  ouch:
1015     if (url != URL)
1016 	fetchFreeURL(url);
1017     if (fd != -1)
1018 	close(fd);
1019     return NULL;
1020 }
1021 
1022 
1023 /*****************************************************************************
1024  * Entry points
1025  */
1026 
1027 /*
1028  * Retrieve and stat a file by HTTP
1029  */
1030 FILE *
1031 fetchXGetHTTP(struct url *URL, struct url_stat *us, char *flags)
1032 {
1033     return _http_request(URL, "GET", us, flags);
1034 }
1035 
1036 /*
1037  * Retrieve a file by HTTP
1038  */
1039 FILE *
1040 fetchGetHTTP(struct url *URL, char *flags)
1041 {
1042     return fetchXGetHTTP(URL, NULL, flags);
1043 }
1044 
1045 /*
1046  * Store a file by HTTP
1047  */
1048 FILE *
1049 fetchPutHTTP(struct url *URL, char *flags)
1050 {
1051     warnx("fetchPutHTTP(): not implemented");
1052     return NULL;
1053 }
1054 
1055 /*
1056  * Get an HTTP document's metadata
1057  */
1058 int
1059 fetchStatHTTP(struct url *URL, struct url_stat *us, char *flags)
1060 {
1061     FILE *f;
1062 
1063     if ((f = _http_request(URL, "HEAD", us, flags)) == NULL)
1064 	return -1;
1065     fclose(f);
1066     return 0;
1067 }
1068 
1069 /*
1070  * List a directory
1071  */
1072 struct url_ent *
1073 fetchListHTTP(struct url *url, char *flags)
1074 {
1075     warnx("fetchListHTTP(): not implemented");
1076     return NULL;
1077 }
1078