c757f898e0fda9a6b2fffbad017c7391ec02d23a
[dragonfly.git] / lib / libfetch / http.c
1 /*-
2  * Copyright (c) 2000-2011 Dag-Erling Smørgrav
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 /*
30  * The following copyright applies to the base64 code:
31  *
32  *-
33  * Copyright 1997 Massachusetts Institute of Technology
34  *
35  * Permission to use, copy, modify, and distribute this software and
36  * its documentation for any purpose and without fee is hereby
37  * granted, provided that both the above copyright notice and this
38  * permission notice appear in all copies, that both the above
39  * copyright notice and this permission notice appear in all
40  * supporting documentation, and that the name of M.I.T. not be used
41  * in advertising or publicity pertaining to distribution of the
42  * software without specific, written prior permission.  M.I.T. makes
43  * no representations about the suitability of this software for any
44  * purpose.  It is provided "as is" without express or implied
45  * warranty.
46  *
47  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
48  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
49  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
50  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
51  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
52  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
53  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
54  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
55  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
56  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
57  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58  * SUCH DAMAGE.
59  */
60
61 #include <sys/param.h>
62 #include <sys/socket.h>
63 #include <sys/time.h>
64
65 #include <ctype.h>
66 #include <err.h>
67 #include <errno.h>
68 #include <locale.h>
69 #include <netdb.h>
70 #include <stdarg.h>
71 #include <stdio.h>
72 #include <stdlib.h>
73 #include <string.h>
74 #include <time.h>
75 #include <unistd.h>
76
77 #ifdef WITH_SSL
78 #include <openssl/md5.h>
79 #define MD5Init(c) MD5_Init(c)
80 #define MD5Update(c, data, len) MD5_Update(c, data, len)
81 #define MD5Final(md, c) MD5_Final(md, c)
82 #else
83 #include <md5.h>
84 #endif
85
86 #include <netinet/in.h>
87 #include <netinet/tcp.h>
88
89 #include "fetch.h"
90 #include "common.h"
91 #include "httperr.h"
92
93 /* Maximum number of redirects to follow */
94 #define MAX_REDIRECT 20
95
96 /* Symbolic names for reply codes we care about */
97 #define HTTP_OK                 200
98 #define HTTP_PARTIAL            206
99 #define HTTP_MOVED_PERM         301
100 #define HTTP_MOVED_TEMP         302
101 #define HTTP_SEE_OTHER          303
102 #define HTTP_NOT_MODIFIED       304
103 #define HTTP_USE_PROXY          305
104 #define HTTP_TEMP_REDIRECT      307
105 #define HTTP_PERM_REDIRECT      308
106 #define HTTP_NEED_AUTH          401
107 #define HTTP_NEED_PROXY_AUTH    407
108 #define HTTP_BAD_RANGE          416
109 #define HTTP_PROTOCOL_ERROR     999
110
111 #define HTTP_REDIRECT(xyz) ((xyz) == HTTP_MOVED_PERM \
112                             || (xyz) == HTTP_MOVED_TEMP \
113                             || (xyz) == HTTP_TEMP_REDIRECT \
114                             || (xyz) == HTTP_USE_PROXY \
115                             || (xyz) == HTTP_SEE_OTHER)
116
117 #define HTTP_ERROR(xyz) ((xyz) > 400 && (xyz) < 599)
118
119
120 /*****************************************************************************
121  * I/O functions for decoding chunked streams
122  */
123
124 struct httpio
125 {
126         conn_t          *conn;          /* connection */
127         int              chunked;       /* chunked mode */
128         char            *buf;           /* chunk buffer */
129         size_t           bufsize;       /* size of chunk buffer */
130         ssize_t          buflen;        /* amount of data currently in buffer */
131         int              bufpos;        /* current read offset in buffer */
132         int              eof;           /* end-of-file flag */
133         int              error;         /* error flag */
134         size_t           chunksize;     /* remaining size of current chunk */
135 #ifndef NDEBUG
136         size_t           total;
137 #endif
138 };
139
140 static int http_cmd(conn_t *, const char *, ...) __printflike(2, 3);
141
142 /*
143  * Get next chunk header
144  */
145 static int
146 http_new_chunk(struct httpio *io)
147 {
148         char *p;
149
150         if (fetch_getln(io->conn) == -1)
151                 return (-1);
152
153         if (io->conn->buflen < 2 || !isxdigit((unsigned char)*io->conn->buf))
154                 return (-1);
155
156         for (p = io->conn->buf; *p && !isspace((unsigned char)*p); ++p) {
157                 if (*p == ';')
158                         break;
159                 if (!isxdigit((unsigned char)*p))
160                         return (-1);
161                 if (isdigit((unsigned char)*p)) {
162                         io->chunksize = io->chunksize * 16 +
163                             *p - '0';
164                 } else {
165                         io->chunksize = io->chunksize * 16 +
166                             10 + tolower((unsigned char)*p) - 'a';
167                 }
168         }
169
170 #ifndef NDEBUG
171         if (fetchDebug) {
172                 io->total += io->chunksize;
173                 if (io->chunksize == 0)
174                         fprintf(stderr, "%s(): end of last chunk\n", __func__);
175                 else
176                         fprintf(stderr, "%s(): new chunk: %lu (%lu)\n",
177                             __func__, (unsigned long)io->chunksize,
178                             (unsigned long)io->total);
179         }
180 #endif
181
182         return (io->chunksize);
183 }
184
185 /*
186  * Grow the input buffer to at least len bytes
187  */
188 static inline int
189 http_growbuf(struct httpio *io, size_t len)
190 {
191         char *tmp;
192
193         if (io->bufsize >= len)
194                 return (0);
195
196         if ((tmp = realloc(io->buf, len)) == NULL)
197                 return (-1);
198         io->buf = tmp;
199         io->bufsize = len;
200         return (0);
201 }
202
203 /*
204  * Fill the input buffer, do chunk decoding on the fly
205  */
206 static int
207 http_fillbuf(struct httpio *io, size_t len)
208 {
209         ssize_t nbytes;
210
211         if (io->error)
212                 return (-1);
213         if (io->eof)
214                 return (0);
215
216         if (io->chunked == 0) {
217                 if (http_growbuf(io, len) == -1)
218                         return (-1);
219                 if ((nbytes = fetch_read(io->conn, io->buf, len)) == -1) {
220                         io->error = errno;
221                         return (-1);
222                 }
223                 io->buflen = nbytes;
224                 io->bufpos = 0;
225                 return (io->buflen);
226         }
227
228         if (io->chunksize == 0) {
229                 switch (http_new_chunk(io)) {
230                 case -1:
231                         io->error = 1;
232                         return (-1);
233                 case 0:
234                         io->eof = 1;
235                         return (0);
236                 }
237         }
238
239         if (len > io->chunksize)
240                 len = io->chunksize;
241         if (http_growbuf(io, len) == -1)
242                 return (-1);
243         if ((nbytes = fetch_read(io->conn, io->buf, len)) == -1) {
244                 io->error = errno;
245                 return (-1);
246         }
247         io->buflen = nbytes;
248         io->chunksize -= io->buflen;
249
250         if (io->chunksize == 0) {
251                 char endl[2];
252
253                 if (fetch_read(io->conn, endl, 2) != 2 ||
254                     endl[0] != '\r' || endl[1] != '\n')
255                         return (-1);
256         }
257
258         io->bufpos = 0;
259
260         return (io->buflen);
261 }
262
263 /*
264  * Read function
265  */
266 static int
267 http_readfn(void *v, char *buf, int len)
268 {
269         struct httpio *io = (struct httpio *)v;
270         int l, pos;
271
272         if (io->error)
273                 return (-1);
274         if (io->eof)
275                 return (0);
276
277         for (pos = 0; len > 0; pos += l, len -= l) {
278                 /* empty buffer */
279                 if (!io->buf || io->bufpos == io->buflen)
280                         if (http_fillbuf(io, len) < 1)
281                                 break;
282                 l = io->buflen - io->bufpos;
283                 if (len < l)
284                         l = len;
285                 memcpy(buf + pos, io->buf + io->bufpos, l);
286                 io->bufpos += l;
287         }
288
289         if (!pos && io->error) {
290                 if (io->error == EINTR)
291                         io->error = 0;
292                 return (-1);
293         }
294         return (pos);
295 }
296
297 /*
298  * Write function
299  */
300 static int
301 http_writefn(void *v, const char *buf, int len)
302 {
303         struct httpio *io = (struct httpio *)v;
304
305         return (fetch_write(io->conn, buf, len));
306 }
307
308 /*
309  * Close function
310  */
311 static int
312 http_closefn(void *v)
313 {
314         struct httpio *io = (struct httpio *)v;
315         int r;
316
317         r = fetch_close(io->conn);
318         if (io->buf)
319                 free(io->buf);
320         free(io);
321         return (r);
322 }
323
324 /*
325  * Wrap a file descriptor up
326  */
327 static FILE *
328 http_funopen(conn_t *conn, int chunked)
329 {
330         struct httpio *io;
331         FILE *f;
332
333         if ((io = calloc(1, sizeof(*io))) == NULL) {
334                 fetch_syserr();
335                 return (NULL);
336         }
337         io->conn = conn;
338         io->chunked = chunked;
339         f = funopen(io, http_readfn, http_writefn, NULL, http_closefn);
340         if (f == NULL) {
341                 fetch_syserr();
342                 free(io);
343                 return (NULL);
344         }
345         return (f);
346 }
347
348
349 /*****************************************************************************
350  * Helper functions for talking to the server and parsing its replies
351  */
352
353 /* Header types */
354 typedef enum {
355         hdr_syserror = -2,
356         hdr_error = -1,
357         hdr_end = 0,
358         hdr_unknown = 1,
359         hdr_content_length,
360         hdr_content_range,
361         hdr_last_modified,
362         hdr_location,
363         hdr_transfer_encoding,
364         hdr_www_authenticate,
365         hdr_proxy_authenticate,
366 } hdr_t;
367
368 /* Names of interesting headers */
369 static struct {
370         hdr_t            num;
371         const char      *name;
372 } hdr_names[] = {
373         { hdr_content_length,           "Content-Length" },
374         { hdr_content_range,            "Content-Range" },
375         { hdr_last_modified,            "Last-Modified" },
376         { hdr_location,                 "Location" },
377         { hdr_transfer_encoding,        "Transfer-Encoding" },
378         { hdr_www_authenticate,         "WWW-Authenticate" },
379         { hdr_proxy_authenticate,       "Proxy-Authenticate" },
380         { hdr_unknown,                  NULL },
381 };
382
383 /*
384  * Send a formatted line; optionally echo to terminal
385  */
386 static int
387 http_cmd(conn_t *conn, const char *fmt, ...)
388 {
389         va_list ap;
390         size_t len;
391         char *msg;
392         int r;
393
394         va_start(ap, fmt);
395         len = vasprintf(&msg, fmt, ap);
396         va_end(ap);
397
398         if (msg == NULL) {
399                 errno = ENOMEM;
400                 fetch_syserr();
401                 return (-1);
402         }
403
404         r = fetch_putln(conn, msg, len);
405         free(msg);
406
407         if (r == -1) {
408                 fetch_syserr();
409                 return (-1);
410         }
411
412         return (0);
413 }
414
415 /*
416  * Get and parse status line
417  */
418 static int
419 http_get_reply(conn_t *conn)
420 {
421         char *p;
422
423         if (fetch_getln(conn) == -1)
424                 return (-1);
425         /*
426          * A valid status line looks like "HTTP/m.n xyz reason" where m
427          * and n are the major and minor protocol version numbers and xyz
428          * is the reply code.
429          * Unfortunately, there are servers out there (NCSA 1.5.1, to name
430          * just one) that do not send a version number, so we can't rely
431          * on finding one, but if we do, insist on it being 1.0 or 1.1.
432          * We don't care about the reason phrase.
433          */
434         if (strncmp(conn->buf, "HTTP", 4) != 0)
435                 return (HTTP_PROTOCOL_ERROR);
436         p = conn->buf + 4;
437         if (*p == '/') {
438                 if (p[1] != '1' || p[2] != '.' || (p[3] != '0' && p[3] != '1'))
439                         return (HTTP_PROTOCOL_ERROR);
440                 p += 4;
441         }
442         if (*p != ' ' ||
443             !isdigit((unsigned char)p[1]) ||
444             !isdigit((unsigned char)p[2]) ||
445             !isdigit((unsigned char)p[3]))
446                 return (HTTP_PROTOCOL_ERROR);
447
448         conn->err = (p[1] - '0') * 100 + (p[2] - '0') * 10 + (p[3] - '0');
449         return (conn->err);
450 }
451
452 /*
453  * Check a header; if the type matches the given string, return a pointer
454  * to the beginning of the value.
455  */
456 static const char *
457 http_match(const char *str, const char *hdr)
458 {
459         while (*str && *hdr &&
460             tolower((unsigned char)*str++) == tolower((unsigned char)*hdr++))
461                 /* nothing */;
462         if (*str || *hdr != ':')
463                 return (NULL);
464         while (*hdr && isspace((unsigned char)*++hdr))
465                 /* nothing */;
466         return (hdr);
467 }
468
469
470 /*
471  * Get the next header and return the appropriate symbolic code.  We
472  * need to read one line ahead for checking for a continuation line
473  * belonging to the current header (continuation lines start with
474  * white space).
475  *
476  * We get called with a fresh line already in the conn buffer, either
477  * from the previous http_next_header() invocation, or, the first
478  * time, from a fetch_getln() performed by our caller.
479  *
480  * This stops when we encounter an empty line (we dont read beyond the header
481  * area).
482  *
483  * Note that the "headerbuf" is just a place to return the result. Its
484  * contents are not used for the next call. This means that no cleanup
485  * is needed when ie doing another connection, just call the cleanup when
486  * fully done to deallocate memory.
487  */
488
489 /* Limit the max number of continuation lines to some reasonable value */
490 #define HTTP_MAX_CONT_LINES 10
491
492 /* Place into which to build a header from one or several lines */
493 typedef struct {
494         char    *buf;           /* buffer */
495         size_t   bufsize;       /* buffer size */
496         size_t   buflen;        /* length of buffer contents */
497 } http_headerbuf_t;
498
499 static void
500 init_http_headerbuf(http_headerbuf_t *buf)
501 {
502         buf->buf = NULL;
503         buf->bufsize = 0;
504         buf->buflen = 0;
505 }
506
507 static void
508 clean_http_headerbuf(http_headerbuf_t *buf)
509 {
510         if (buf->buf)
511                 free(buf->buf);
512         init_http_headerbuf(buf);
513 }
514
515 /* Remove whitespace at the end of the buffer */
516 static void
517 http_conn_trimright(conn_t *conn)
518 {
519         while (conn->buflen &&
520                isspace((unsigned char)conn->buf[conn->buflen - 1]))
521                 conn->buflen--;
522         conn->buf[conn->buflen] = '\0';
523 }
524
525 static hdr_t
526 http_next_header(conn_t *conn, http_headerbuf_t *hbuf, const char **p)
527 {
528         unsigned int i, len;
529
530         /*
531          * Have to do the stripping here because of the first line. So
532          * it's done twice for the subsequent lines. No big deal
533          */
534         http_conn_trimright(conn);
535         if (conn->buflen == 0)
536                 return (hdr_end);
537
538         /* Copy the line to the headerbuf */
539         if (hbuf->bufsize < conn->buflen + 1) {
540                 if ((hbuf->buf = realloc(hbuf->buf, conn->buflen + 1)) == NULL)
541                         return (hdr_syserror);
542                 hbuf->bufsize = conn->buflen + 1;
543         }
544         strcpy(hbuf->buf, conn->buf);
545         hbuf->buflen = conn->buflen;
546
547         /*
548          * Fetch possible continuation lines. Stop at 1st non-continuation
549          * and leave it in the conn buffer
550          */
551         for (i = 0; i < HTTP_MAX_CONT_LINES; i++) {
552                 if (fetch_getln(conn) == -1)
553                         return (hdr_syserror);
554
555                 /*
556                  * Note: we carry on the idea from the previous version
557                  * that a pure whitespace line is equivalent to an empty
558                  * one (so it's not continuation and will be handled when
559                  * we are called next)
560                  */
561                 http_conn_trimright(conn);
562                 if (conn->buf[0] != ' ' && conn->buf[0] != "\t"[0])
563                         break;
564
565                 /* Got a continuation line. Concatenate to previous */
566                 len = hbuf->buflen + conn->buflen;
567                 if (hbuf->bufsize < len + 1) {
568                         len *= 2;
569                         if ((hbuf->buf = realloc(hbuf->buf, len + 1)) == NULL)
570                                 return (hdr_syserror);
571                         hbuf->bufsize = len + 1;
572                 }
573                 strcpy(hbuf->buf + hbuf->buflen, conn->buf);
574                 hbuf->buflen += conn->buflen;
575         }
576
577         /*
578          * We could check for malformed headers but we don't really care.
579          * A valid header starts with a token immediately followed by a
580          * colon; a token is any sequence of non-control, non-whitespace
581          * characters except "()<>@,;:\\\"{}".
582          */
583         for (i = 0; hdr_names[i].num != hdr_unknown; i++)
584                 if ((*p = http_match(hdr_names[i].name, hbuf->buf)) != NULL)
585                         return (hdr_names[i].num);
586
587         return (hdr_unknown);
588 }
589
590 /**************************
591  * [Proxy-]Authenticate header parsing
592  */
593
594 /*
595  * Read doublequote-delimited string into output buffer obuf (allocated
596  * by caller, whose responsibility it is to ensure that it's big enough)
597  * cp points to the first char after the initial '"'
598  * Handles \ quoting
599  * Returns pointer to the first char after the terminating double quote, or
600  * NULL for error.
601  */
602 static const char *
603 http_parse_headerstring(const char *cp, char *obuf)
604 {
605         for (;;) {
606                 switch (*cp) {
607                 case 0: /* Unterminated string */
608                         *obuf = 0;
609                         return (NULL);
610                 case '"': /* Ending quote */
611                         *obuf = 0;
612                         return (++cp);
613                 case '\\':
614                         if (*++cp == 0) {
615                                 *obuf = 0;
616                                 return (NULL);
617                         }
618                         /* FALLTHROUGH */
619                 default:
620                         *obuf++ = *cp++;
621                 }
622         }
623 }
624
625 /* Http auth challenge schemes */
626 typedef enum {HTTPAS_UNKNOWN, HTTPAS_BASIC,HTTPAS_DIGEST} http_auth_schemes_t;
627
628 /* Data holder for a Basic or Digest challenge. */
629 typedef struct {
630         http_auth_schemes_t scheme;
631         char    *realm;
632         char    *qop;
633         char    *nonce;
634         char    *opaque;
635         char    *algo;
636         int      stale;
637         int      nc; /* Nonce count */
638 } http_auth_challenge_t;
639
640 static void
641 init_http_auth_challenge(http_auth_challenge_t *b)
642 {
643         b->scheme = HTTPAS_UNKNOWN;
644         b->realm = b->qop = b->nonce = b->opaque = b->algo = NULL;
645         b->stale = b->nc = 0;
646 }
647
648 static void
649 clean_http_auth_challenge(http_auth_challenge_t *b)
650 {
651         if (b->realm)
652                 free(b->realm);
653         if (b->qop)
654                 free(b->qop);
655         if (b->nonce)
656                 free(b->nonce);
657         if (b->opaque)
658                 free(b->opaque);
659         if (b->algo)
660                 free(b->algo);
661         init_http_auth_challenge(b);
662 }
663
664 /* Data holder for an array of challenges offered in an http response. */
665 #define MAX_CHALLENGES 10
666 typedef struct {
667         http_auth_challenge_t *challenges[MAX_CHALLENGES];
668         int     count; /* Number of parsed challenges in the array */
669         int     valid; /* We did parse an authenticate header */
670 } http_auth_challenges_t;
671
672 static void
673 init_http_auth_challenges(http_auth_challenges_t *cs)
674 {
675         int i;
676         for (i = 0; i < MAX_CHALLENGES; i++)
677                 cs->challenges[i] = NULL;
678         cs->count = cs->valid = 0;
679 }
680
681 static void
682 clean_http_auth_challenges(http_auth_challenges_t *cs)
683 {
684         int i;
685         /* We rely on non-zero pointers being allocated, not on the count */
686         for (i = 0; i < MAX_CHALLENGES; i++) {
687                 if (cs->challenges[i] != NULL) {
688                         clean_http_auth_challenge(cs->challenges[i]);
689                         free(cs->challenges[i]);
690                 }
691         }
692         init_http_auth_challenges(cs);
693 }
694
695 /*
696  * Enumeration for lexical elements. Separators will be returned as their own
697  * ascii value
698  */
699 typedef enum {HTTPHL_WORD=256, HTTPHL_STRING=257, HTTPHL_END=258,
700               HTTPHL_ERROR = 259} http_header_lex_t;
701
702 /*
703  * Determine what kind of token comes next and return possible value
704  * in buf, which is supposed to have been allocated big enough by
705  * caller. Advance input pointer and return element type.
706  */
707 static int
708 http_header_lex(const char **cpp, char *buf)
709 {
710         size_t l;
711         /* Eat initial whitespace */
712         *cpp += strspn(*cpp, " \t");
713         if (**cpp == 0)
714                 return (HTTPHL_END);
715
716         /* Separator ? */
717         if (**cpp == ',' || **cpp == '=')
718                 return (*((*cpp)++));
719
720         /* String ? */
721         if (**cpp == '"') {
722                 *cpp = http_parse_headerstring(++*cpp, buf);
723                 if (*cpp == NULL)
724                         return (HTTPHL_ERROR);
725                 return (HTTPHL_STRING);
726         }
727
728         /* Read other token, until separator or whitespace */
729         l = strcspn(*cpp, " \t,=");
730         memcpy(buf, *cpp, l);
731         buf[l] = 0;
732         *cpp += l;
733         return (HTTPHL_WORD);
734 }
735
736 /*
737  * Read challenges from http xxx-authenticate header and accumulate them
738  * in the challenges list structure.
739  *
740  * Headers with multiple challenges are specified by rfc2617, but
741  * servers (ie: squid) often send them in separate headers instead,
742  * which in turn is forbidden by the http spec (multiple headers with
743  * the same name are only allowed for pure comma-separated lists, see
744  * rfc2616 sec 4.2).
745  *
746  * We support both approaches anyway
747  */
748 static int
749 http_parse_authenticate(const char *cp, http_auth_challenges_t *cs)
750 {
751         int ret = -1;
752         http_header_lex_t lex;
753         char *key = malloc(strlen(cp) + 1);
754         char *value = malloc(strlen(cp) + 1);
755         char *buf = malloc(strlen(cp) + 1);
756
757         if (key == NULL || value == NULL || buf == NULL) {
758                 fetch_syserr();
759                 goto out;
760         }
761
762         /* In any case we've seen the header and we set the valid bit */
763         cs->valid = 1;
764
765         /* Need word first */
766         lex = http_header_lex(&cp, key);
767         if (lex != HTTPHL_WORD)
768                 goto out;
769
770         /* Loop on challenges */
771         for (; cs->count < MAX_CHALLENGES; cs->count++) {
772                 cs->challenges[cs->count] =
773                         malloc(sizeof(http_auth_challenge_t));
774                 if (cs->challenges[cs->count] == NULL) {
775                         fetch_syserr();
776                         goto out;
777                 }
778                 init_http_auth_challenge(cs->challenges[cs->count]);
779                 if (!strcasecmp(key, "basic")) {
780                         cs->challenges[cs->count]->scheme = HTTPAS_BASIC;
781                 } else if (!strcasecmp(key, "digest")) {
782                         cs->challenges[cs->count]->scheme = HTTPAS_DIGEST;
783                 } else {
784                         cs->challenges[cs->count]->scheme = HTTPAS_UNKNOWN;
785                         /*
786                          * Continue parsing as basic or digest may
787                          * follow, and the syntax is the same for
788                          * all. We'll just ignore this one when
789                          * looking at the list
790                          */
791                 }
792
793                 /* Loop on attributes */
794                 for (;;) {
795                         /* Key */
796                         lex = http_header_lex(&cp, key);
797                         if (lex != HTTPHL_WORD)
798                                 goto out;
799
800                         /* Equal sign */
801                         lex = http_header_lex(&cp, buf);
802                         if (lex != '=')
803                                 goto out;
804
805                         /* Value */
806                         lex = http_header_lex(&cp, value);
807                         if (lex != HTTPHL_WORD && lex != HTTPHL_STRING)
808                                 goto out;
809
810                         if (!strcasecmp(key, "realm"))
811                                 cs->challenges[cs->count]->realm =
812                                         strdup(value);
813                         else if (!strcasecmp(key, "qop"))
814                                 cs->challenges[cs->count]->qop =
815                                         strdup(value);
816                         else if (!strcasecmp(key, "nonce"))
817                                 cs->challenges[cs->count]->nonce =
818                                         strdup(value);
819                         else if (!strcasecmp(key, "opaque"))
820                                 cs->challenges[cs->count]->opaque =
821                                         strdup(value);
822                         else if (!strcasecmp(key, "algorithm"))
823                                 cs->challenges[cs->count]->algo =
824                                         strdup(value);
825                         else if (!strcasecmp(key, "stale"))
826                                 cs->challenges[cs->count]->stale =
827                                         strcasecmp(value, "no");
828                         /* Else ignore unknown attributes */
829
830                         /* Comma or Next challenge or End */
831                         lex = http_header_lex(&cp, key);
832                         /*
833                          * If we get a word here, this is the beginning of the
834                          * next challenge. Break the attributes loop
835                          */
836                         if (lex == HTTPHL_WORD)
837                                 break;
838
839                         if (lex == HTTPHL_END) {
840                                 /* End while looking for ',' is normal exit */
841                                 cs->count++;
842                                 ret = 0;
843                                 goto out;
844                         }
845                         /* Anything else is an error */
846                         if (lex != ',')
847                                 goto out;
848
849                 } /* End attributes loop */
850         } /* End challenge loop */
851
852         /*
853          * Challenges max count exceeded. This really can't happen
854          * with normal data, something's fishy -> error
855          */
856
857 out:
858         if (key)
859                 free(key);
860         if (value)
861                 free(value);
862         if (buf)
863                 free(buf);
864         return (ret);
865 }
866
867
868 /*
869  * Parse a last-modified header
870  */
871 static int
872 http_parse_mtime(const char *p, time_t *mtime)
873 {
874         char locale[64], *r;
875         struct tm tm;
876
877         strncpy(locale, setlocale(LC_TIME, NULL), sizeof(locale));
878         setlocale(LC_TIME, "C");
879         r = strptime(p, "%a, %d %b %Y %H:%M:%S GMT", &tm);
880         /* XXX should add support for date-2 and date-3 */
881         setlocale(LC_TIME, locale);
882         if (r == NULL)
883                 return (-1);
884         DEBUG(fprintf(stderr, "last modified: [%04d-%02d-%02d "
885                   "%02d:%02d:%02d]\n",
886                   tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
887                   tm.tm_hour, tm.tm_min, tm.tm_sec));
888         *mtime = timegm(&tm);
889         return (0);
890 }
891
892 /*
893  * Parse a content-length header
894  */
895 static int
896 http_parse_length(const char *p, off_t *length)
897 {
898         off_t len;
899
900         for (len = 0; *p && isdigit((unsigned char)*p); ++p)
901                 len = len * 10 + (*p - '0');
902         if (*p)
903                 return (-1);
904         DEBUG(fprintf(stderr, "content length: [%lld]\n",
905             (long long)len));
906         *length = len;
907         return (0);
908 }
909
910 /*
911  * Parse a content-range header
912  */
913 static int
914 http_parse_range(const char *p, off_t *offset, off_t *length, off_t *size)
915 {
916         off_t first, last, len;
917
918         if (strncasecmp(p, "bytes ", 6) != 0)
919                 return (-1);
920         p += 6;
921         if (*p == '*') {
922                 first = last = -1;
923                 ++p;
924         } else {
925                 for (first = 0; *p && isdigit((unsigned char)*p); ++p)
926                         first = first * 10 + *p - '0';
927                 if (*p != '-')
928                         return (-1);
929                 for (last = 0, ++p; *p && isdigit((unsigned char)*p); ++p)
930                         last = last * 10 + *p - '0';
931         }
932         if (first > last || *p != '/')
933                 return (-1);
934         for (len = 0, ++p; *p && isdigit((unsigned char)*p); ++p)
935                 len = len * 10 + *p - '0';
936         if (*p || len < last - first + 1)
937                 return (-1);
938         if (first == -1) {
939                 DEBUG(fprintf(stderr, "content range: [*/%lld]\n",
940                     (long long)len));
941                 *length = 0;
942         } else {
943                 DEBUG(fprintf(stderr, "content range: [%lld-%lld/%lld]\n",
944                     (long long)first, (long long)last, (long long)len));
945                 *length = last - first + 1;
946         }
947         *offset = first;
948         *size = len;
949         return (0);
950 }
951
952
953 /*****************************************************************************
954  * Helper functions for authorization
955  */
956
957 /*
958  * Base64 encoding
959  */
960 static char *
961 http_base64(const char *src)
962 {
963         static const char base64[] =
964             "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
965             "abcdefghijklmnopqrstuvwxyz"
966             "0123456789+/";
967         char *str, *dst;
968         size_t l;
969         int t, r;
970
971         l = strlen(src);
972         if ((str = malloc(((l + 2) / 3) * 4 + 1)) == NULL)
973                 return (NULL);
974         dst = str;
975         r = 0;
976
977         while (l >= 3) {
978                 t = (src[0] << 16) | (src[1] << 8) | src[2];
979                 dst[0] = base64[(t >> 18) & 0x3f];
980                 dst[1] = base64[(t >> 12) & 0x3f];
981                 dst[2] = base64[(t >> 6) & 0x3f];
982                 dst[3] = base64[(t >> 0) & 0x3f];
983                 src += 3; l -= 3;
984                 dst += 4; r += 4;
985         }
986
987         switch (l) {
988         case 2:
989                 t = (src[0] << 16) | (src[1] << 8);
990                 dst[0] = base64[(t >> 18) & 0x3f];
991                 dst[1] = base64[(t >> 12) & 0x3f];
992                 dst[2] = base64[(t >> 6) & 0x3f];
993                 dst[3] = '=';
994                 dst += 4;
995                 r += 4;
996                 break;
997         case 1:
998                 t = src[0] << 16;
999                 dst[0] = base64[(t >> 18) & 0x3f];
1000                 dst[1] = base64[(t >> 12) & 0x3f];
1001                 dst[2] = dst[3] = '=';
1002                 dst += 4;
1003                 r += 4;
1004                 break;
1005         case 0:
1006                 break;
1007         }
1008
1009         *dst = 0;
1010         return (str);
1011 }
1012
1013
1014 /*
1015  * Extract authorization parameters from environment value.
1016  * The value is like scheme:realm:user:pass
1017  */
1018 typedef struct {
1019         char    *scheme;
1020         char    *realm;
1021         char    *user;
1022         char    *password;
1023 } http_auth_params_t;
1024
1025 static void
1026 init_http_auth_params(http_auth_params_t *s)
1027 {
1028         s->scheme = s->realm = s->user = s->password = 0;
1029 }
1030
1031 static void
1032 clean_http_auth_params(http_auth_params_t *s)
1033 {
1034         if (s->scheme)
1035                 free(s->scheme);
1036         if (s->realm)
1037                 free(s->realm);
1038         if (s->user)
1039                 free(s->user);
1040         if (s->password)
1041                 free(s->password);
1042         init_http_auth_params(s);
1043 }
1044
1045 static int
1046 http_authfromenv(const char *p, http_auth_params_t *parms)
1047 {
1048         int ret = -1;
1049         char *v, *ve;
1050         char *str = strdup(p);
1051
1052         if (str == NULL) {
1053                 fetch_syserr();
1054                 return (-1);
1055         }
1056         v = str;
1057
1058         if ((ve = strchr(v, ':')) == NULL)
1059                 goto out;
1060
1061         *ve = 0;
1062         if ((parms->scheme = strdup(v)) == NULL) {
1063                 fetch_syserr();
1064                 goto out;
1065         }
1066         v = ve + 1;
1067
1068         if ((ve = strchr(v, ':')) == NULL)
1069                 goto out;
1070
1071         *ve = 0;
1072         if ((parms->realm = strdup(v)) == NULL) {
1073                 fetch_syserr();
1074                 goto out;
1075         }
1076         v = ve + 1;
1077
1078         if ((ve = strchr(v, ':')) == NULL)
1079                 goto out;
1080
1081         *ve = 0;
1082         if ((parms->user = strdup(v)) == NULL) {
1083                 fetch_syserr();
1084                 goto out;
1085         }
1086         v = ve + 1;
1087
1088
1089         if ((parms->password = strdup(v)) == NULL) {
1090                 fetch_syserr();
1091                 goto out;
1092         }
1093         ret = 0;
1094 out:
1095         if (ret == -1)
1096                 clean_http_auth_params(parms);
1097         if (str)
1098                 free(str);
1099         return (ret);
1100 }
1101
1102
1103 /*
1104  * Digest response: the code to compute the digest is taken from the
1105  * sample implementation in RFC2616
1106  */
1107 #define IN const
1108 #define OUT
1109
1110 #define HASHLEN 16
1111 typedef char HASH[HASHLEN];
1112 #define HASHHEXLEN 32
1113 typedef char HASHHEX[HASHHEXLEN+1];
1114
1115 static const char *hexchars = "0123456789abcdef";
1116 static void
1117 CvtHex(IN HASH Bin, OUT HASHHEX Hex)
1118 {
1119         unsigned short i;
1120         unsigned char j;
1121
1122         for (i = 0; i < HASHLEN; i++) {
1123                 j = (Bin[i] >> 4) & 0xf;
1124                 Hex[i*2] = hexchars[j];
1125                 j = Bin[i] & 0xf;
1126                 Hex[i*2+1] = hexchars[j];
1127         };
1128         Hex[HASHHEXLEN] = '\0';
1129 };
1130
1131 /* calculate H(A1) as per spec */
1132 static void
1133 DigestCalcHA1(
1134         IN char * pszAlg,
1135         IN char * pszUserName,
1136         IN char * pszRealm,
1137         IN char * pszPassword,
1138         IN char * pszNonce,
1139         IN char * pszCNonce,
1140         OUT HASHHEX SessionKey
1141         )
1142 {
1143         MD5_CTX Md5Ctx;
1144         HASH HA1;
1145
1146         MD5Init(&Md5Ctx);
1147         MD5Update(&Md5Ctx, pszUserName, strlen(pszUserName));
1148         MD5Update(&Md5Ctx, ":", 1);
1149         MD5Update(&Md5Ctx, pszRealm, strlen(pszRealm));
1150         MD5Update(&Md5Ctx, ":", 1);
1151         MD5Update(&Md5Ctx, pszPassword, strlen(pszPassword));
1152         MD5Final(HA1, &Md5Ctx);
1153         if (strcasecmp(pszAlg, "md5-sess") == 0) {
1154
1155                 MD5Init(&Md5Ctx);
1156                 MD5Update(&Md5Ctx, HA1, HASHLEN);
1157                 MD5Update(&Md5Ctx, ":", 1);
1158                 MD5Update(&Md5Ctx, pszNonce, strlen(pszNonce));
1159                 MD5Update(&Md5Ctx, ":", 1);
1160                 MD5Update(&Md5Ctx, pszCNonce, strlen(pszCNonce));
1161                 MD5Final(HA1, &Md5Ctx);
1162         };
1163         CvtHex(HA1, SessionKey);
1164 }
1165
1166 /* calculate request-digest/response-digest as per HTTP Digest spec */
1167 static void
1168 DigestCalcResponse(
1169         IN HASHHEX HA1,           /* H(A1) */
1170         IN char * pszNonce,       /* nonce from server */
1171         IN char * pszNonceCount,  /* 8 hex digits */
1172         IN char * pszCNonce,      /* client nonce */
1173         IN char * pszQop,         /* qop-value: "", "auth", "auth-int" */
1174         IN char * pszMethod,      /* method from the request */
1175         IN char * pszDigestUri,   /* requested URL */
1176         IN HASHHEX HEntity,       /* H(entity body) if qop="auth-int" */
1177         OUT HASHHEX Response      /* request-digest or response-digest */
1178         )
1179 {
1180 /*      DEBUG(fprintf(stderr,
1181                       "Calc: HA1[%s] Nonce[%s] qop[%s] method[%s] URI[%s]\n",
1182                       HA1, pszNonce, pszQop, pszMethod, pszDigestUri));*/
1183         MD5_CTX Md5Ctx;
1184         HASH HA2;
1185         HASH RespHash;
1186         HASHHEX HA2Hex;
1187
1188         // calculate H(A2)
1189         MD5Init(&Md5Ctx);
1190         MD5Update(&Md5Ctx, pszMethod, strlen(pszMethod));
1191         MD5Update(&Md5Ctx, ":", 1);
1192         MD5Update(&Md5Ctx, pszDigestUri, strlen(pszDigestUri));
1193         if (strcasecmp(pszQop, "auth-int") == 0) {
1194                 MD5Update(&Md5Ctx, ":", 1);
1195                 MD5Update(&Md5Ctx, HEntity, HASHHEXLEN);
1196         };
1197         MD5Final(HA2, &Md5Ctx);
1198         CvtHex(HA2, HA2Hex);
1199
1200         // calculate response
1201         MD5Init(&Md5Ctx);
1202         MD5Update(&Md5Ctx, HA1, HASHHEXLEN);
1203         MD5Update(&Md5Ctx, ":", 1);
1204         MD5Update(&Md5Ctx, pszNonce, strlen(pszNonce));
1205         MD5Update(&Md5Ctx, ":", 1);
1206         if (*pszQop) {
1207                 MD5Update(&Md5Ctx, pszNonceCount, strlen(pszNonceCount));
1208                 MD5Update(&Md5Ctx, ":", 1);
1209                 MD5Update(&Md5Ctx, pszCNonce, strlen(pszCNonce));
1210                 MD5Update(&Md5Ctx, ":", 1);
1211                 MD5Update(&Md5Ctx, pszQop, strlen(pszQop));
1212                 MD5Update(&Md5Ctx, ":", 1);
1213         };
1214         MD5Update(&Md5Ctx, HA2Hex, HASHHEXLEN);
1215         MD5Final(RespHash, &Md5Ctx);
1216         CvtHex(RespHash, Response);
1217 }
1218
1219 /*
1220  * Generate/Send a Digest authorization header
1221  * This looks like: [Proxy-]Authorization: credentials
1222  *
1223  *  credentials      = "Digest" digest-response
1224  *  digest-response  = 1#( username | realm | nonce | digest-uri
1225  *                      | response | [ algorithm ] | [cnonce] |
1226  *                      [opaque] | [message-qop] |
1227  *                          [nonce-count]  | [auth-param] )
1228  *  username         = "username" "=" username-value
1229  *  username-value   = quoted-string
1230  *  digest-uri       = "uri" "=" digest-uri-value
1231  *  digest-uri-value = request-uri   ; As specified by HTTP/1.1
1232  *  message-qop      = "qop" "=" qop-value
1233  *  cnonce           = "cnonce" "=" cnonce-value
1234  *  cnonce-value     = nonce-value
1235  *  nonce-count      = "nc" "=" nc-value
1236  *  nc-value         = 8LHEX
1237  *  response         = "response" "=" request-digest
1238  *  request-digest = <"> 32LHEX <">
1239  */
1240 static int
1241 http_digest_auth(conn_t *conn, const char *hdr, http_auth_challenge_t *c,
1242                  http_auth_params_t *parms, struct url *url)
1243 {
1244         int r;
1245         char noncecount[10];
1246         char cnonce[40];
1247         char *options = 0;
1248
1249         if (!c->realm || !c->nonce) {
1250                 DEBUG(fprintf(stderr, "realm/nonce not set in challenge\n"));
1251                 return(-1);
1252         }
1253         if (!c->algo)
1254                 c->algo = strdup("");
1255
1256         if (asprintf(&options, "%s%s%s%s",
1257                      *c->algo? ",algorithm=" : "", c->algo,
1258                      c->opaque? ",opaque=" : "", c->opaque?c->opaque:"")== -1)
1259                 return (-1);
1260
1261         if (!c->qop) {
1262                 c->qop = strdup("");
1263                 *noncecount = 0;
1264                 *cnonce = 0;
1265         } else {
1266                 c->nc++;
1267                 sprintf(noncecount, "%08x", c->nc);
1268                 /* We don't try very hard with the cnonce ... */
1269                 sprintf(cnonce, "%x%lx", getpid(), (unsigned long)time(0));
1270         }
1271
1272         HASHHEX HA1;
1273         DigestCalcHA1(c->algo, parms->user, c->realm,
1274                       parms->password, c->nonce, cnonce, HA1);
1275         DEBUG(fprintf(stderr, "HA1: [%s]\n", HA1));
1276         HASHHEX digest;
1277         DigestCalcResponse(HA1, c->nonce, noncecount, cnonce, c->qop,
1278                            "GET", url->doc, "", digest);
1279
1280         if (c->qop[0]) {
1281                 r = http_cmd(conn, "%s: Digest username=\"%s\",realm=\"%s\","
1282                              "nonce=\"%s\",uri=\"%s\",response=\"%s\","
1283                              "qop=\"auth\", cnonce=\"%s\", nc=%s%s",
1284                              hdr, parms->user, c->realm,
1285                              c->nonce, url->doc, digest,
1286                              cnonce, noncecount, options);
1287         } else {
1288                 r = http_cmd(conn, "%s: Digest username=\"%s\",realm=\"%s\","
1289                              "nonce=\"%s\",uri=\"%s\",response=\"%s\"%s",
1290                              hdr, parms->user, c->realm,
1291                              c->nonce, url->doc, digest, options);
1292         }
1293         if (options)
1294                 free(options);
1295         return (r);
1296 }
1297
1298 /*
1299  * Encode username and password
1300  */
1301 static int
1302 http_basic_auth(conn_t *conn, const char *hdr, const char *usr, const char *pwd)
1303 {
1304         char *upw, *auth;
1305         int r;
1306
1307         DEBUG(fprintf(stderr, "basic: usr: [%s]\n", usr));
1308         DEBUG(fprintf(stderr, "basic: pwd: [%s]\n", pwd));
1309         if (asprintf(&upw, "%s:%s", usr, pwd) == -1)
1310                 return (-1);
1311         auth = http_base64(upw);
1312         free(upw);
1313         if (auth == NULL)
1314                 return (-1);
1315         r = http_cmd(conn, "%s: Basic %s", hdr, auth);
1316         free(auth);
1317         return (r);
1318 }
1319
1320 /*
1321  * Chose the challenge to answer and call the appropriate routine to
1322  * produce the header.
1323  */
1324 static int
1325 http_authorize(conn_t *conn, const char *hdr, http_auth_challenges_t *cs,
1326                http_auth_params_t *parms, struct url *url)
1327 {
1328         http_auth_challenge_t *basic = NULL;
1329         http_auth_challenge_t *digest = NULL;
1330         int i;
1331
1332         /* If user or pass are null we're not happy */
1333         if (!parms->user || !parms->password) {
1334                 DEBUG(fprintf(stderr, "NULL usr or pass\n"));
1335                 return (-1);
1336         }
1337
1338         /* Look for a Digest and a Basic challenge */
1339         for (i = 0; i < cs->count; i++) {
1340                 if (cs->challenges[i]->scheme == HTTPAS_BASIC)
1341                         basic = cs->challenges[i];
1342                 if (cs->challenges[i]->scheme == HTTPAS_DIGEST)
1343                         digest = cs->challenges[i];
1344         }
1345
1346         /* Error if "Digest" was specified and there is no Digest challenge */
1347         if (!digest && (parms->scheme &&
1348                         !strcasecmp(parms->scheme, "digest"))) {
1349                 DEBUG(fprintf(stderr,
1350                               "Digest auth in env, not supported by peer\n"));
1351                 return (-1);
1352         }
1353         /*
1354          * If "basic" was specified in the environment, or there is no Digest
1355          * challenge, do the basic thing. Don't need a challenge for this,
1356          * so no need to check basic!=NULL
1357          */
1358         if (!digest || (parms->scheme && !strcasecmp(parms->scheme,"basic")))
1359                 return (http_basic_auth(conn,hdr,parms->user,parms->password));
1360
1361         /* Else, prefer digest. We just checked that it's not NULL */
1362         return (http_digest_auth(conn, hdr, digest, parms, url));
1363 }
1364
1365 /*****************************************************************************
1366  * Helper functions for connecting to a server or proxy
1367  */
1368
1369 /*
1370  * Connect to the correct HTTP server or proxy.
1371  */
1372 static conn_t *
1373 http_connect(struct url *URL, struct url *purl, const char *flags)
1374 {
1375         conn_t *conn;
1376         int verbose;
1377         int af, val;
1378
1379 #ifdef INET6
1380         af = AF_UNSPEC;
1381 #else
1382         af = AF_INET;
1383 #endif
1384
1385         verbose = CHECK_FLAG('v');
1386         if (CHECK_FLAG('4'))
1387                 af = AF_INET;
1388 #ifdef INET6
1389         else if (CHECK_FLAG('6'))
1390                 af = AF_INET6;
1391 #endif
1392
1393         if (purl && strcasecmp(URL->scheme, SCHEME_HTTPS) != 0) {
1394                 URL = purl;
1395         } else if (strcasecmp(URL->scheme, SCHEME_FTP) == 0) {
1396                 /* can't talk http to an ftp server */
1397                 /* XXX should set an error code */
1398                 return (NULL);
1399         }
1400
1401         if ((conn = fetch_connect(URL->host, URL->port, af, verbose)) == NULL)
1402                 /* fetch_connect() has already set an error code */
1403                 return (NULL);
1404         if (strcasecmp(URL->scheme, SCHEME_HTTPS) == 0 &&
1405             fetch_ssl(conn, verbose) == -1) {
1406                 fetch_close(conn);
1407                 /* grrr */
1408                 errno = EAUTH;
1409                 fetch_syserr();
1410                 return (NULL);
1411         }
1412
1413         val = 1;
1414         setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val, sizeof(val));
1415
1416         return (conn);
1417 }
1418
1419 static struct url *
1420 http_get_proxy(struct url * url, const char *flags)
1421 {
1422         struct url *purl;
1423         char *p;
1424
1425         if (flags != NULL && strchr(flags, 'd') != NULL)
1426                 return (NULL);
1427         if (fetch_no_proxy_match(url->host))
1428                 return (NULL);
1429         if (((p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
1430             *p && (purl = fetchParseURL(p))) {
1431                 if (!*purl->scheme)
1432                         strcpy(purl->scheme, SCHEME_HTTP);
1433                 if (!purl->port)
1434                         purl->port = fetch_default_proxy_port(purl->scheme);
1435                 if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
1436                         return (purl);
1437                 fetchFreeURL(purl);
1438         }
1439         return (NULL);
1440 }
1441
1442 static void
1443 http_print_html(FILE *out, FILE *in)
1444 {
1445         size_t len;
1446         char *line, *p, *q;
1447         int comment, tag;
1448
1449         comment = tag = 0;
1450         while ((line = fgetln(in, &len)) != NULL) {
1451                 while (len && isspace((unsigned char)line[len - 1]))
1452                         --len;
1453                 for (p = q = line; q < line + len; ++q) {
1454                         if (comment && *q == '-') {
1455                                 if (q + 2 < line + len &&
1456                                     strcmp(q, "-->") == 0) {
1457                                         tag = comment = 0;
1458                                         q += 2;
1459                                 }
1460                         } else if (tag && !comment && *q == '>') {
1461                                 p = q + 1;
1462                                 tag = 0;
1463                         } else if (!tag && *q == '<') {
1464                                 if (q > p)
1465                                         fwrite(p, q - p, 1, out);
1466                                 tag = 1;
1467                                 if (q + 3 < line + len &&
1468                                     strcmp(q, "<!--") == 0) {
1469                                         comment = 1;
1470                                         q += 3;
1471                                 }
1472                         }
1473                 }
1474                 if (!tag && q > p)
1475                         fwrite(p, q - p, 1, out);
1476                 fputc('\n', out);
1477         }
1478 }
1479
1480
1481 /*****************************************************************************
1482  * Core
1483  */
1484
1485 /*
1486  * Send a request and process the reply
1487  *
1488  * XXX This function is way too long, the do..while loop should be split
1489  * XXX off into a separate function.
1490  */
1491 FILE *
1492 http_request(struct url *URL, const char *op, struct url_stat *us,
1493         struct url *purl, const char *flags)
1494 {
1495         char timebuf[80];
1496         char hbuf[MAXHOSTNAMELEN + 7], *host;
1497         conn_t *conn;
1498         struct url *url, *new;
1499         int chunked, direct, ims, noredirect, verbose;
1500         int e, i, n, val;
1501         off_t offset, clength, length, size;
1502         time_t mtime;
1503         const char *p;
1504         FILE *f;
1505         hdr_t h;
1506         struct tm *timestruct;
1507         http_headerbuf_t headerbuf;
1508         http_auth_challenges_t server_challenges;
1509         http_auth_challenges_t proxy_challenges;
1510
1511         /* The following calls don't allocate anything */
1512         init_http_headerbuf(&headerbuf);
1513         init_http_auth_challenges(&server_challenges);
1514         init_http_auth_challenges(&proxy_challenges);
1515
1516         direct = CHECK_FLAG('d');
1517         noredirect = CHECK_FLAG('A');
1518         verbose = CHECK_FLAG('v');
1519         ims = CHECK_FLAG('i');
1520
1521         if (direct && purl) {
1522                 fetchFreeURL(purl);
1523                 purl = NULL;
1524         }
1525
1526         /* try the provided URL first */
1527         url = URL;
1528
1529         n = MAX_REDIRECT;
1530         i = 0;
1531
1532         e = HTTP_PROTOCOL_ERROR;
1533         do {
1534                 new = NULL;
1535                 chunked = 0;
1536                 offset = 0;
1537                 clength = -1;
1538                 length = -1;
1539                 size = -1;
1540                 mtime = 0;
1541
1542                 /* check port */
1543                 if (!url->port)
1544                         url->port = fetch_default_port(url->scheme);
1545
1546                 /* were we redirected to an FTP URL? */
1547                 if (purl == NULL && strcmp(url->scheme, SCHEME_FTP) == 0) {
1548                         if (strcmp(op, "GET") == 0)
1549                                 return (ftp_request(url, "RETR", us, purl, flags));
1550                         else if (strcmp(op, "HEAD") == 0)
1551                                 return (ftp_request(url, "STAT", us, purl, flags));
1552                 }
1553
1554                 /* connect to server or proxy */
1555                 if ((conn = http_connect(url, purl, flags)) == NULL)
1556                         goto ouch;
1557
1558                 host = url->host;
1559 #ifdef INET6
1560                 if (strchr(url->host, ':')) {
1561                         snprintf(hbuf, sizeof(hbuf), "[%s]", url->host);
1562                         host = hbuf;
1563                 }
1564 #endif
1565                 if (url->port != fetch_default_port(url->scheme)) {
1566                         if (host != hbuf) {
1567                                 strcpy(hbuf, host);
1568                                 host = hbuf;
1569                         }
1570                         snprintf(hbuf + strlen(hbuf),
1571                             sizeof(hbuf) - strlen(hbuf), ":%d", url->port);
1572                 }
1573
1574                 /* send request */
1575                 if (verbose)
1576                         fetch_info("requesting %s://%s%s",
1577                             url->scheme, host, url->doc);
1578                 if (purl) {
1579                         http_cmd(conn, "%s %s://%s%s HTTP/1.1",
1580                             op, url->scheme, host, url->doc);
1581                 } else {
1582                         http_cmd(conn, "%s %s HTTP/1.1",
1583                             op, url->doc);
1584                 }
1585
1586                 if (ims && url->ims_time) {
1587                         timestruct = gmtime((time_t *)&url->ims_time);
1588                         (void)strftime(timebuf, 80, "%a, %d %b %Y %T GMT",
1589                             timestruct);
1590                         if (verbose)
1591                                 fetch_info("If-Modified-Since: %s", timebuf);
1592                         http_cmd(conn, "If-Modified-Since: %s", timebuf);
1593                 }
1594                 /* virtual host */
1595                 http_cmd(conn, "Host: %s", host);
1596
1597                 /*
1598                  * Proxy authorization: we only send auth after we received
1599                  * a 407 error. We do not first try basic anyway (changed
1600                  * when support was added for digest-auth)
1601                  */
1602                 if (purl && proxy_challenges.valid) {
1603                         http_auth_params_t aparams;
1604                         init_http_auth_params(&aparams);
1605                         if (*purl->user || *purl->pwd) {
1606                                 aparams.user = purl->user ?
1607                                         strdup(purl->user) : strdup("");
1608                                 aparams.password = purl->pwd?
1609                                         strdup(purl->pwd) : strdup("");
1610                         } else if ((p = getenv("HTTP_PROXY_AUTH")) != NULL &&
1611                                    *p != '\0') {
1612                                 if (http_authfromenv(p, &aparams) < 0) {
1613                                         http_seterr(HTTP_NEED_PROXY_AUTH);
1614                                         goto ouch;
1615                                 }
1616                         }
1617                         http_authorize(conn, "Proxy-Authorization",
1618                                        &proxy_challenges, &aparams, url);
1619                         clean_http_auth_params(&aparams);
1620                 }
1621
1622                 /*
1623                  * Server authorization: we never send "a priori"
1624                  * Basic auth, which used to be done if user/pass were
1625                  * set in the url. This would be weird because we'd send the
1626                  * password in the clear even if Digest is finally to be
1627                  * used (it would have made more sense for the
1628                  * pre-digest version to do this when Basic was specified
1629                  * in the environment)
1630                  */
1631                 if (server_challenges.valid) {
1632                         http_auth_params_t aparams;
1633                         init_http_auth_params(&aparams);
1634                         if (*url->user || *url->pwd) {
1635                                 aparams.user = url->user ?
1636                                         strdup(url->user) : strdup("");
1637                                 aparams.password = url->pwd ?
1638                                         strdup(url->pwd) : strdup("");
1639                         } else if ((p = getenv("HTTP_AUTH")) != NULL &&
1640                                    *p != '\0') {
1641                                 if (http_authfromenv(p, &aparams) < 0) {
1642                                         http_seterr(HTTP_NEED_AUTH);
1643                                         goto ouch;
1644                                 }
1645                         } else if (fetchAuthMethod &&
1646                                    fetchAuthMethod(url) == 0) {
1647                                 aparams.user = url->user ?
1648                                         strdup(url->user) : strdup("");
1649                                 aparams.password = url->pwd ?
1650                                         strdup(url->pwd) : strdup("");
1651                         } else {
1652                                 http_seterr(HTTP_NEED_AUTH);
1653                                 goto ouch;
1654                         }
1655                         http_authorize(conn, "Authorization",
1656                                        &server_challenges, &aparams, url);
1657                         clean_http_auth_params(&aparams);
1658                 }
1659
1660                 /* other headers */
1661                 if ((p = getenv("HTTP_REFERER")) != NULL && *p != '\0') {
1662                         if (strcasecmp(p, "auto") == 0)
1663                                 http_cmd(conn, "Referer: %s://%s%s",
1664                                     url->scheme, host, url->doc);
1665                         else
1666                                 http_cmd(conn, "Referer: %s", p);
1667                 }
1668                 if ((p = getenv("HTTP_USER_AGENT")) != NULL && *p != '\0')
1669                         http_cmd(conn, "User-Agent: %s", p);
1670                 else
1671                         http_cmd(conn, "User-Agent: %s " _LIBFETCH_VER, getprogname());
1672                 if (url->offset > 0)
1673                         http_cmd(conn, "Range: bytes=%lld-", (long long)url->offset);
1674                 http_cmd(conn, "Connection: close");
1675                 http_cmd(conn, "%s", "");
1676
1677                 /*
1678                  * Force the queued request to be dispatched.  Normally, one
1679                  * would do this with shutdown(2) but squid proxies can be
1680                  * configured to disallow such half-closed connections.  To
1681                  * be compatible with such configurations, fiddle with socket
1682                  * options to force the pending data to be written.
1683                  */
1684                 val = 0;
1685                 setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val,
1686                            sizeof(val));
1687                 val = 1;
1688                 setsockopt(conn->sd, IPPROTO_TCP, TCP_NODELAY, &val,
1689                            sizeof(val));
1690
1691                 /* get reply */
1692                 switch (http_get_reply(conn)) {
1693                 case HTTP_OK:
1694                 case HTTP_PARTIAL:
1695                 case HTTP_NOT_MODIFIED:
1696                         /* fine */
1697                         break;
1698                 case HTTP_MOVED_PERM:
1699                 case HTTP_MOVED_TEMP:
1700                 case HTTP_SEE_OTHER:
1701                 case HTTP_USE_PROXY:
1702                         /*
1703                          * Not so fine, but we still have to read the
1704                          * headers to get the new location.
1705                          */
1706                         break;
1707                 case HTTP_NEED_AUTH:
1708                         if (server_challenges.valid) {
1709                                 /*
1710                                  * We already sent out authorization code,
1711                                  * so there's nothing more we can do.
1712                                  */
1713                                 http_seterr(conn->err);
1714                                 goto ouch;
1715                         }
1716                         /* try again, but send the password this time */
1717                         if (verbose)
1718                                 fetch_info("server requires authorization");
1719                         break;
1720                 case HTTP_NEED_PROXY_AUTH:
1721                         if (proxy_challenges.valid) {
1722                                 /*
1723                                  * We already sent our proxy
1724                                  * authorization code, so there's
1725                                  * nothing more we can do. */
1726                                 http_seterr(conn->err);
1727                                 goto ouch;
1728                         }
1729                         /* try again, but send the password this time */
1730                         if (verbose)
1731                                 fetch_info("proxy requires authorization");
1732                         break;
1733                 case HTTP_BAD_RANGE:
1734                         /*
1735                          * This can happen if we ask for 0 bytes because
1736                          * we already have the whole file.  Consider this
1737                          * a success for now, and check sizes later.
1738                          */
1739                         break;
1740                 case HTTP_PROTOCOL_ERROR:
1741                         /* fall through */
1742                 case -1:
1743                         fetch_syserr();
1744                         goto ouch;
1745                 default:
1746                         http_seterr(conn->err);
1747                         if (!verbose)
1748                                 goto ouch;
1749                         /* fall through so we can get the full error message */
1750                 }
1751
1752                 /* get headers. http_next_header expects one line readahead */
1753                 if (fetch_getln(conn) == -1) {
1754                     fetch_syserr();
1755                     goto ouch;
1756                 }
1757                 do {
1758                     switch ((h = http_next_header(conn, &headerbuf, &p))) {
1759                         case hdr_syserror:
1760                                 fetch_syserr();
1761                                 goto ouch;
1762                         case hdr_error:
1763                                 http_seterr(HTTP_PROTOCOL_ERROR);
1764                                 goto ouch;
1765                         case hdr_content_length:
1766                                 http_parse_length(p, &clength);
1767                                 break;
1768                         case hdr_content_range:
1769                                 http_parse_range(p, &offset, &length, &size);
1770                                 break;
1771                         case hdr_last_modified:
1772                                 http_parse_mtime(p, &mtime);
1773                                 break;
1774                         case hdr_location:
1775                                 if (!HTTP_REDIRECT(conn->err))
1776                                         break;
1777                                 /*
1778                                  * if the A flag is set, we don't follow
1779                                  * temporary redirects.
1780                                  */
1781                                 if (noredirect &&
1782                                     conn->err != HTTP_MOVED_PERM &&
1783                                     conn->err != HTTP_PERM_REDIRECT &&
1784                                     conn->err != HTTP_USE_PROXY) {
1785                                         n = 1;
1786                                         break;
1787                                 }
1788                                 if (new)
1789                                         free(new);
1790                                 if (verbose)
1791                                         fetch_info("%d redirect to %s", conn->err, p);
1792                                 if (*p == '/')
1793                                         /* absolute path */
1794                                         new = fetchMakeURL(url->scheme, url->host, url->port, p,
1795                                             url->user, url->pwd);
1796                                 else
1797                                         new = fetchParseURL(p);
1798                                 if (new == NULL) {
1799                                         /* XXX should set an error code */
1800                                         DEBUG(fprintf(stderr, "failed to parse new URL\n"));
1801                                         goto ouch;
1802                                 }
1803
1804                                 /* Only copy credentials if the host matches */
1805                                 if (!strcmp(new->host, url->host) && !*new->user && !*new->pwd) {
1806                                         strcpy(new->user, url->user);
1807                                         strcpy(new->pwd, url->pwd);
1808                                 }
1809                                 new->offset = url->offset;
1810                                 new->length = url->length;
1811                                 break;
1812                         case hdr_transfer_encoding:
1813                                 /* XXX weak test*/
1814                                 chunked = (strcasecmp(p, "chunked") == 0);
1815                                 break;
1816                         case hdr_www_authenticate:
1817                                 if (conn->err != HTTP_NEED_AUTH)
1818                                         break;
1819                                 if (http_parse_authenticate(p, &server_challenges) == 0)
1820                                         ++n;
1821                                 break;
1822                         case hdr_proxy_authenticate:
1823                                 if (conn->err != HTTP_NEED_PROXY_AUTH)
1824                                         break;
1825                                 if (http_parse_authenticate(p, &proxy_challenges) == 0)
1826                                         ++n;
1827                                 break;
1828                         case hdr_end:
1829                                 /* fall through */
1830                         case hdr_unknown:
1831                                 /* ignore */
1832                                 break;
1833                         }
1834                 } while (h > hdr_end);
1835
1836                 /* we need to provide authentication */
1837                 if (conn->err == HTTP_NEED_AUTH ||
1838                     conn->err == HTTP_NEED_PROXY_AUTH) {
1839                         e = conn->err;
1840                         if ((conn->err == HTTP_NEED_AUTH &&
1841                              !server_challenges.valid) ||
1842                             (conn->err == HTTP_NEED_PROXY_AUTH &&
1843                              !proxy_challenges.valid)) {
1844                                 /* 401/7 but no www/proxy-authenticate ?? */
1845                                 DEBUG(fprintf(stderr, "401/7 and no auth header\n"));
1846                                 goto ouch;
1847                         }
1848                         fetch_close(conn);
1849                         conn = NULL;
1850                         continue;
1851                 }
1852
1853                 /* requested range not satisfiable */
1854                 if (conn->err == HTTP_BAD_RANGE) {
1855                         if (url->offset == size && url->length == 0) {
1856                                 /* asked for 0 bytes; fake it */
1857                                 offset = url->offset;
1858                                 clength = -1;
1859                                 conn->err = HTTP_OK;
1860                                 break;
1861                         } else {
1862                                 http_seterr(conn->err);
1863                                 goto ouch;
1864                         }
1865                 }
1866
1867                 /* we have a hit or an error */
1868                 if (conn->err == HTTP_OK
1869                     || conn->err == HTTP_NOT_MODIFIED
1870                     || conn->err == HTTP_PARTIAL
1871                     || HTTP_ERROR(conn->err))
1872                         break;
1873
1874                 /* all other cases: we got a redirect */
1875                 e = conn->err;
1876                 clean_http_auth_challenges(&server_challenges);
1877                 fetch_close(conn);
1878                 conn = NULL;
1879                 if (!new) {
1880                         DEBUG(fprintf(stderr, "redirect with no new location\n"));
1881                         break;
1882                 }
1883                 if (url != URL)
1884                         fetchFreeURL(url);
1885                 url = new;
1886         } while (++i < n);
1887
1888         /* we failed, or ran out of retries */
1889         if (conn == NULL) {
1890                 http_seterr(e);
1891                 goto ouch;
1892         }
1893
1894         DEBUG(fprintf(stderr, "offset %lld, length %lld,"
1895                   " size %lld, clength %lld\n",
1896                   (long long)offset, (long long)length,
1897                   (long long)size, (long long)clength));
1898
1899         if (conn->err == HTTP_NOT_MODIFIED) {
1900                 http_seterr(HTTP_NOT_MODIFIED);
1901                 return (NULL);
1902         }
1903
1904         /* check for inconsistencies */
1905         if (clength != -1 && length != -1 && clength != length) {
1906                 http_seterr(HTTP_PROTOCOL_ERROR);
1907                 goto ouch;
1908         }
1909         if (clength == -1)
1910                 clength = length;
1911         if (clength != -1)
1912                 length = offset + clength;
1913         if (length != -1 && size != -1 && length != size) {
1914                 http_seterr(HTTP_PROTOCOL_ERROR);
1915                 goto ouch;
1916         }
1917         if (size == -1)
1918                 size = length;
1919
1920         /* fill in stats */
1921         if (us) {
1922                 us->size = size;
1923                 us->atime = us->mtime = mtime;
1924         }
1925
1926         /* too far? */
1927         if (URL->offset > 0 && offset > URL->offset) {
1928                 http_seterr(HTTP_PROTOCOL_ERROR);
1929                 goto ouch;
1930         }
1931
1932         /* report back real offset and size */
1933         URL->offset = offset;
1934         URL->length = clength;
1935
1936         /* wrap it up in a FILE */
1937         if ((f = http_funopen(conn, chunked)) == NULL) {
1938                 fetch_syserr();
1939                 goto ouch;
1940         }
1941
1942         if (url != URL)
1943                 fetchFreeURL(url);
1944         if (purl)
1945                 fetchFreeURL(purl);
1946
1947         if (HTTP_ERROR(conn->err)) {
1948                 http_print_html(stderr, f);
1949                 fclose(f);
1950                 f = NULL;
1951         }
1952         clean_http_headerbuf(&headerbuf);
1953         clean_http_auth_challenges(&server_challenges);
1954         clean_http_auth_challenges(&proxy_challenges);
1955         return (f);
1956
1957 ouch:
1958         if (url != URL)
1959                 fetchFreeURL(url);
1960         if (purl)
1961                 fetchFreeURL(purl);
1962         if (conn != NULL)
1963                 fetch_close(conn);
1964         clean_http_headerbuf(&headerbuf);
1965         clean_http_auth_challenges(&server_challenges);
1966         clean_http_auth_challenges(&proxy_challenges);
1967         return (NULL);
1968 }
1969
1970
1971 /*****************************************************************************
1972  * Entry points
1973  */
1974
1975 /*
1976  * Retrieve and stat a file by HTTP
1977  */
1978 FILE *
1979 fetchXGetHTTP(struct url *URL, struct url_stat *us, const char *flags)
1980 {
1981         return (http_request(URL, "GET", us, http_get_proxy(URL, flags), flags));
1982 }
1983
1984 /*
1985  * Retrieve a file by HTTP
1986  */
1987 FILE *
1988 fetchGetHTTP(struct url *URL, const char *flags)
1989 {
1990         return (fetchXGetHTTP(URL, NULL, flags));
1991 }
1992
1993 /*
1994  * Store a file by HTTP
1995  */
1996 FILE *
1997 fetchPutHTTP(struct url *URL __unused, const char *flags __unused)
1998 {
1999         warnx("fetchPutHTTP(): not implemented");
2000         return (NULL);
2001 }
2002
2003 /*
2004  * Get an HTTP document's metadata
2005  */
2006 int
2007 fetchStatHTTP(struct url *URL, struct url_stat *us, const char *flags)
2008 {
2009         FILE *f;
2010
2011         f = http_request(URL, "HEAD", us, http_get_proxy(URL, flags), flags);
2012         if (f == NULL)
2013                 return (-1);
2014         fclose(f);
2015         return (0);
2016 }
2017
2018 /*
2019  * List a directory
2020  */
2021 struct url_ent *
2022 fetchListHTTP(struct url *url __unused, const char *flags __unused)
2023 {
2024         warnx("fetchListHTTP(): not implemented");
2025         return (NULL);
2026 }