share/examples/refuse/ian/libfetch/http.c

   1 /*-
   2  * Copyright (c) 2000-2004 Dag-Erling Coïdan 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 #include "free2net.h"
  30
  31 #include <sys/cdefs.h>
  32 __FBSDID("$FreeBSD: src/lib/libfetch/http.c,v 1.76.2.2 2007/05/29 12:35:26 des Exp $");
  33
  34 /*
  35  * The following copyright applies to the base64 code:
  36  *
  37  *-
  38  * Copyright 1997 Massachusetts Institute of Technology
  39  *
  40  * Permission to use, copy, modify, and distribute this software and
  41  * its documentation for any purpose and without fee is hereby
  42  * granted, provided that both the above copyright notice and this
  43  * permission notice appear in all copies, that both the above
  44  * copyright notice and this permission notice appear in all
  45  * supporting documentation, and that the name of M.I.T. not be used
  46  * in advertising or publicity pertaining to distribution of the
  47  * software without specific, written prior permission.  M.I.T. makes
  48  * no representations about the suitability of this software for any
  49  * purpose.  It is provided "as is" without express or implied
  50  * warranty.
  51  *
  52  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
  53  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
  54  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  55  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
  56  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  57  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  58  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  59  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  60  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  61  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  62  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  63  * SUCH DAMAGE.
  64  */
  65
  66 #include <sys/param.h>
  67 #include <sys/socket.h>
  68
  69 #include <ctype.h>
  70 #include <err.h>
  71 #include <errno.h>
  72 #include <locale.h>
  73 #include <netdb.h>
  74 #include <stdarg.h>
  75 #include <stdio.h>
  76 #include <stdlib.h>
  77 #include <string.h>
  78 #include <time.h>
  79 #include <unistd.h>
  80
  81 #include <netinet/in.h>
  82 #include <netinet/tcp.h>
  83
  84 #include "fetch.h"
  85 #include "common.h"
  86 #include "httperr.h"
  87
  88 #include "free2net.h"
  89
  90 /* Maximum number of redirects to follow */
  91 #define MAX_REDIRECT 5
  92
  93 /* Symbolic names for reply codes we care about */
  94 #define HTTP_OK                 200
  95 #define HTTP_PARTIAL            206
  96 #define HTTP_MOVED_PERM         301
  97 #define HTTP_MOVED_TEMP         302
  98 #define HTTP_SEE_OTHER          303
  99 #define HTTP_TEMP_REDIRECT      307
 100 #define HTTP_NEED_AUTH          401
 101 #define HTTP_NEED_PROXY_AUTH    407
 102 #define HTTP_BAD_RANGE          416
 103 #define HTTP_PROTOCOL_ERROR     999
 104
 105 #define HTTP_REDIRECT(xyz) ((xyz) == HTTP_MOVED_PERM \
 106                             || (xyz) == HTTP_MOVED_TEMP \
 107                             || (xyz) == HTTP_TEMP_REDIRECT \
 108                             || (xyz) == HTTP_SEE_OTHER)
 109
 110 #define HTTP_ERROR(xyz) ((xyz) > 400 && (xyz) < 599)
 111
 112
 113 /*****************************************************************************
 114  * I/O functions for decoding chunked streams
 115  */
 116
 117 struct httpio
 118 {
 119         conn_t          *conn;          /* connection */
 120         int              chunked;       /* chunked mode */
 121         char            *buf;           /* chunk buffer */
 122         size_t           bufsize;       /* size of chunk buffer */
 123         ssize_t          buflen;        /* amount of data currently in buffer */
 124         int              bufpos;        /* current read offset in buffer */
 125         int              eof;           /* end-of-file flag */
 126         int              error;         /* error flag */
 127         size_t           chunksize;     /* remaining size of current chunk */
 128 #ifndef NDEBUG
 129         size_t           total;
 130 #endif
 131 };
 132
 133
 134 /*
 135  * Get next chunk header
 136  */
 137 static int
 138 _http_new_chunk(struct httpio *io)
 139 {
 140         char *p;
 141
 142         if (_fetch_getln(io->conn) == -1)
 143                 return (-1);
 144
 145         if (io->conn->buflen < 2 || !ishexnumber((unsigned)*io->conn->buf))
 146                 return (-1);
 147
 148         for (p = io->conn->buf; *p && !isspace((unsigned)*p); ++p) {
 149                 if (*p == ';')
 150                         break;
 151                 if (!ishexnumber((unsigned)*p))
 152                         return (-1);
 153                 if (isdigit((unsigned)*p)) {
 154                         io->chunksize = io->chunksize * 16 +
 155                             *p - '0';
 156                 } else {
 157                         io->chunksize = io->chunksize * 16 +
 158                             10 + tolower((unsigned)*p) - 'a';
 159                 }
 160         }
 161
 162 #ifndef NDEBUG
 163         if (fetchDebug) {
 164                 io->total += io->chunksize;
 165                 if (io->chunksize == 0)
 166                         fprintf(stderr, "%s(): end of last chunk\n", __func__);
 167                 else
 168                         fprintf(stderr, "%s(): new chunk: %lu (%lu)\n",
 169                             __func__, (unsigned long)io->chunksize,
 170                             (unsigned long)io->total);
 171         }
 172 #endif
 173
 174         return (io->chunksize);
 175 }
 176
 177 /*
 178  * Grow the input buffer to at least len bytes
 179  */
 180 static inline int
 181 _http_growbuf(struct httpio *io, size_t len)
 182 {
 183         char *tmp;
 184
 185         if (io->bufsize >= len)
 186                 return (0);
 187
 188         if ((tmp = realloc(io->buf, len)) == NULL)
 189                 return (-1);
 190         io->buf = tmp;
 191         io->bufsize = len;
 192         return (0);
 193 }
 194
 195 /*
 196  * Fill the input buffer, do chunk decoding on the fly
 197  */
 198 static int
 199 _http_fillbuf(struct httpio *io, size_t len)
 200 {
 201         if (io->error)
 202                 return (-1);
 203         if (io->eof)
 204                 return (0);
 205
 206         if (io->chunked == 0) {
 207                 if (_http_growbuf(io, len) == -1)
 208                         return (-1);
 209                 if ((io->buflen = _fetch_read(io->conn, io->buf, len)) == -1) {
 210                         io->error = 1;
 211                         return (-1);
 212                 }
 213                 io->bufpos = 0;
 214                 return (io->buflen);
 215         }
 216
 217         if (io->chunksize == 0) {
 218                 switch (_http_new_chunk(io)) {
 219                 case -1:
 220                         io->error = 1;
 221                         return (-1);
 222                 case 0:
 223                         io->eof = 1;
 224                         return (0);
 225                 }
 226         }
 227
 228         if (len > io->chunksize)
 229                 len = io->chunksize;
 230         if (_http_growbuf(io, len) == -1)
 231                 return (-1);
 232         if ((io->buflen = _fetch_read(io->conn, io->buf, len)) == -1) {
 233                 io->error = 1;
 234                 return (-1);
 235         }
 236         io->chunksize -= io->buflen;
 237
 238         if (io->chunksize == 0) {
 239                 char endl[2];
 240
 241                 if (_fetch_read(io->conn, endl, 2) != 2 ||
 242                     endl[0] != '\r' || endl[1] != '\n')
 243                         return (-1);
 244         }
 245
 246         io->bufpos = 0;
 247
 248         return (io->buflen);
 249 }
 250
 251 /*
 252  * Read function
 253  */
 254 static int
 255 _http_readfn(void *v, char *buf, int len)
 256 {
 257         struct httpio *io = (struct httpio *)v;
 258         int l, pos;
 259
 260         if (io->error)
 261                 return (-1);
 262         if (io->eof)
 263                 return (0);
 264
 265         for (pos = 0; len > 0; pos += l, len -= l) {
 266                 /* empty buffer */
 267                 if (!io->buf || io->bufpos == io->buflen)
 268                         if (_http_fillbuf(io, (unsigned) len) < 1)
 269                                 break;
 270                 l = io->buflen - io->bufpos;
 271                 if (len < l)
 272                         l = len;
 273                 bcopy(io->buf + io->bufpos, buf + pos, (unsigned) l);
 274                 io->bufpos += l;
 275         }
 276
 277         if (!pos && io->error)
 278                 return (-1);
 279         return (pos);
 280 }
 281
 282 /*
 283  * Write function
 284  */
 285 static int
 286 _http_writefn(void *v, const char *buf, int len)
 287 {
 288         struct httpio *io = (struct httpio *)v;
 289
 290         return (_fetch_write(io->conn, buf, (unsigned) len));
 291 }
 292
 293 /*
 294  * Close function
 295  */
 296 static int
 297 _http_closefn(void *v)
 298 {
 299         struct httpio *io = (struct httpio *)v;
 300         int r;
 301
 302         r = _fetch_close(io->conn);
 303         if (io->buf)
 304                 free(io->buf);
 305         free(io);
 306         return (r);
 307 }
 308
 309 /*
 310  * Wrap a file descriptor up
 311  */
 312 static FILE *
 313 _http_funopen(conn_t *conn, int chunked)
 314 {
 315         struct httpio *io;
 316         FILE *f;
 317
 318         if ((io = calloc(1, sizeof(*io))) == NULL) {
 319                 _fetch_syserr();
 320                 return (NULL);
 321         }
 322         io->conn = conn;
 323         io->chunked = chunked;
 324         f = funopen(io, _http_readfn, _http_writefn, NULL, _http_closefn);
 325         if (f == NULL) {
 326                 _fetch_syserr();
 327                 free(io);
 328                 return (NULL);
 329         }
 330         return (f);
 331 }
 332
 333
 334 /*****************************************************************************
 335  * Helper functions for talking to the server and parsing its replies
 336  */
 337
 338 /* Header types */
 339 typedef enum {
 340         hdr_syserror = -2,
 341         hdr_error = -1,
 342         hdr_end = 0,
 343         hdr_unknown = 1,
 344         hdr_content_length,
 345         hdr_content_range,
 346         hdr_last_modified,
 347         hdr_location,
 348         hdr_transfer_encoding,
 349         hdr_www_authenticate
 350 } hdr_t;
 351
 352 /* Names of interesting headers */
 353 static struct {
 354         hdr_t            num;
 355         const char      *name;
 356 } hdr_names[] = {
 357         { hdr_content_length,           "Content-Length" },
 358         { hdr_content_range,            "Content-Range" },
 359         { hdr_last_modified,            "Last-Modified" },
 360         { hdr_location,                 "Location" },
 361         { hdr_transfer_encoding,        "Transfer-Encoding" },
 362         { hdr_www_authenticate,         "WWW-Authenticate" },
 363         { hdr_unknown,                  NULL },
 364 };
 365
 366 /*
 367  * Send a formatted line; optionally echo to terminal
 368  */
 369 static int
 370 _http_cmd(conn_t *conn, const char *fmt, ...)
 371 {
 372         va_list ap;
 373         size_t len;
 374         char *msg;
 375         int r;
 376
 377         va_start(ap, fmt);
 378         len = vasprintf(&msg, fmt, ap);
 379         va_end(ap);
 380
 381         if (msg == NULL) {
 382                 errno = ENOMEM;
 383                 _fetch_syserr();
 384                 return (-1);
 385         }
 386
 387         r = _fetch_putln(conn, msg, len);
 388         free(msg);
 389
 390         if (r == -1) {
 391                 _fetch_syserr();
 392                 return (-1);
 393         }
 394
 395         return (0);
 396 }
 397
 398 /*
 399  * Get and parse status line
 400  */
 401 static int
 402 _http_get_reply(conn_t *conn)
 403 {
 404         char *p;
 405
 406         if (_fetch_getln(conn) == -1)
 407                 return (-1);
 408         /*
 409          * A valid status line looks like "HTTP/m.n xyz reason" where m
 410          * and n are the major and minor protocol version numbers and xyz
 411          * is the reply code.
 412          * Unfortunately, there are servers out there (NCSA 1.5.1, to name
 413          * just one) that do not send a version number, so we can't rely
 414          * on finding one, but if we do, insist on it being 1.0 or 1.1.
 415          * We don't care about the reason phrase.
 416          */
 417         if (strncmp(conn->buf, "HTTP", 4) != 0)
 418                 return (HTTP_PROTOCOL_ERROR);
 419         p = conn->buf + 4;
 420         if (*p == '/') {
 421                 if (p[1] != '1' || p[2] != '.' || (p[3] != '0' && p[3] != '1'))
 422                         return (HTTP_PROTOCOL_ERROR);
 423                 p += 4;
 424         }
 425         if (*p != ' ' || !isdigit((unsigned)p[1]) || !isdigit((unsigned)p[2]) || !isdigit((unsigned)p[3]))
 426                 return (HTTP_PROTOCOL_ERROR);
 427
 428         conn->err = (p[1] - '0') * 100 + (p[2] - '0') * 10 + (p[3] - '0');
 429         return (conn->err);
 430 }
 431
 432 /*
 433  * Check a header; if the type matches the given string, return a pointer
 434  * to the beginning of the value.
 435  */
 436 static const char *
 437 _http_match(const char *str, const char *hdr)
 438 {
 439         while (*str && *hdr && tolower((unsigned)*str++) == tolower((unsigned)*hdr++))
 440                 /* nothing */;
 441         if (*str || *hdr != ':')
 442                 return (NULL);
 443         while (*hdr && isspace((unsigned)*++hdr))
 444                 /* nothing */;
 445         return (hdr);
 446 }
 447
 448 /*
 449  * Get the next header and return the appropriate symbolic code.
 450  */
 451 static hdr_t
 452 _http_next_header(conn_t *conn, const char **p)
 453 {
 454         int i;
 455
 456         if (_fetch_getln(conn) == -1)
 457                 return (hdr_syserror);
 458         while (conn->buflen && isspace((unsigned)conn->buf[conn->buflen - 1]))
 459                 conn->buflen--;
 460         conn->buf[conn->buflen] = '\0';
 461         if (conn->buflen == 0)
 462                 return (hdr_end);
 463         /*
 464          * We could check for malformed headers but we don't really care.
 465          * A valid header starts with a token immediately followed by a
 466          * colon; a token is any sequence of non-control, non-whitespace
 467          * characters except "()<>@,;:\\\"{}".
 468          */
 469         for (i = 0; hdr_names[i].num != hdr_unknown; i++)
 470                 if ((*p = _http_match(hdr_names[i].name, conn->buf)) != NULL)
 471                         return (hdr_names[i].num);
 472         return (hdr_unknown);
 473 }
 474
 475 /*
 476  * Parse a last-modified header
 477  */
 478 static int
 479 _http_parse_mtime(const char *p, time_t *mtime)
 480 {
 481         char locale[64], *r;
 482         struct tm tm;
 483
 484         strncpy(locale, setlocale(LC_TIME, NULL), sizeof(locale));
 485         setlocale(LC_TIME, "C");
 486         r = strptime(p, "%a, %d %b %Y %H:%M:%S GMT", &tm);
 487         /* XXX should add support for date-2 and date-3 */
 488         setlocale(LC_TIME, locale);
 489         if (r == NULL)
 490                 return (-1);
 491         DEBUG(fprintf(stderr, "last modified: [%04d-%02d-%02d "
 492                   "%02d:%02d:%02d]\n",
 493                   tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 494                   tm.tm_hour, tm.tm_min, tm.tm_sec));
 495         *mtime = timegm(&tm);
 496         return (0);
 497 }
 498
 499 /*
 500  * Parse a content-length header
 501  */
 502 static int
 503 _http_parse_length(const char *p, off_t *length)
 504 {
 505         off_t len;
 506
 507         for (len = 0; *p && isdigit((unsigned)*p); ++p)
 508                 len = len * 10 + (*p - '0');
 509         if (*p)
 510                 return (-1);
 511         DEBUG(fprintf(stderr, "content length: [%lld]\n",
 512             (long long)len));
 513         *length = len;
 514         return (0);
 515 }
 516
 517 /*
 518  * Parse a content-range header
 519  */
 520 static int
 521 _http_parse_range(const char *p, off_t *offset, off_t *length, off_t *size)
 522 {
 523         off_t first, last, len;
 524
 525         if (strncasecmp(p, "bytes ", 6) != 0)
 526                 return (-1);
 527         p += 6;
 528         if (*p == '*') {
 529                 first = last = -1;
 530                 ++p;
 531         } else {
 532                 for (first = 0; *p && isdigit((unsigned)*p); ++p)
 533                         first = first * 10 + *p - '0';
 534                 if (*p != '-')
 535                         return (-1);
 536                 for (last = 0, ++p; *p && isdigit((unsigned)*p); ++p)
 537                         last = last * 10 + *p - '0';
 538         }
 539         if (first > last || *p != '/')
 540                 return (-1);
 541         for (len = 0, ++p; *p && isdigit((unsigned)*p); ++p)
 542                 len = len * 10 + *p - '0';
 543         if (*p || len < last - first + 1)
 544                 return (-1);
 545         if (first == -1) {
 546                 DEBUG(fprintf(stderr, "content range: [*/%lld]\n",
 547                     (long long)len));
 548                 *length = 0;
 549         } else {
 550                 DEBUG(fprintf(stderr, "content range: [%lld-%lld/%lld]\n",
 551                     (long long)first, (long long)last, (long long)len));
 552                 *length = last - first + 1;
 553         }
 554         *offset = first;
 555         *size = len;
 556         return (0);
 557 }
 558
 559
 560 /*****************************************************************************
 561  * Helper functions for authorization
 562  */
 563
 564 /*
 565  * Base64 encoding
 566  */
 567 static char *
 568 _http_base64(const char *src)
 569 {
 570         static const char base64[] =
 571             "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 572             "abcdefghijklmnopqrstuvwxyz"
 573             "0123456789+/";
 574         char *str, *dst;
 575         size_t l;
 576         int r;
 577         unsigned t;
 578
 579         l = strlen(src);
 580         if ((str = malloc(((l + 2) / 3) * 4 + 1)) == NULL)
 581                 return (NULL);
 582         dst = str;
 583         r = 0;
 584
 585         while (l >= 3) {
 586                 t = (src[0] << 16) | (src[1] << 8) | src[2];
 587                 dst[0] = base64[(t >> 18) & 0x3f];
 588                 dst[1] = base64[(t >> 12) & 0x3f];
 589                 dst[2] = base64[(t >> 6) & 0x3f];
 590                 dst[3] = base64[(t >> 0) & 0x3f];
 591                 src += 3; l -= 3;
 592                 dst += 4; r += 4;
 593         }
 594
 595         switch (l) {
 596         case 2:
 597                 t = (src[0] << 16) | (src[1] << 8);
 598                 dst[0] = base64[(t >> 18) & 0x3f];
 599                 dst[1] = base64[(t >> 12) & 0x3f];
 600                 dst[2] = base64[(t >> 6) & 0x3f];
 601                 dst[3] = '=';
 602                 dst += 4;
 603                 r += 4;
 604                 break;
 605         case 1:
 606                 t = src[0] << 16;
 607                 dst[0] = base64[(t >> 18) & 0x3f];
 608                 dst[1] = base64[(t >> 12) & 0x3f];
 609                 dst[2] = dst[3] = '=';
 610                 dst += 4;
 611                 r += 4;
 612                 break;
 613         case 0:
 614                 break;
 615         }
 616
 617         *dst = 0;
 618         return (str);
 619 }
 620
 621 /*
 622  * Encode username and password
 623  */
 624 static int
 625 _http_basic_auth(conn_t *conn, const char *hdr, const char *usr, const char *pwd)
 626 {
 627         char *upw, *auth;
 628         int r;
 629
 630         DEBUG(fprintf(stderr, "usr: [%s]\n", usr));
 631         DEBUG(fprintf(stderr, "pwd: [%s]\n", pwd));
 632         if (asprintf(&upw, "%s:%s", usr, pwd) == -1)
 633                 return (-1);
 634         auth = _http_base64(upw);
 635         free(upw);
 636         if (auth == NULL)
 637                 return (-1);
 638         r = _http_cmd(conn, "%s: Basic %s", hdr, auth);
 639         free(auth);
 640         return (r);
 641 }
 642
 643 /*
 644  * Send an authorization header
 645  */
 646 static int
 647 _http_authorize(conn_t *conn, const char *hdr, const char *p)
 648 {
 649         /* basic authorization */
 650         if (strncasecmp(p, "basic:", 6) == 0) {
 651                 char *user, *pwd, *str;
 652                 int r;
 653
 654                 /* skip realm */
 655                 for (p += 6; *p && *p != ':'; ++p)
 656                         /* nothing */ ;
 657                 if (!*p || strchr(++p, ':') == NULL)
 658                         return (-1);
 659                 if ((str = strdup(p)) == NULL)
 660                         return (-1); /* XXX */
 661                 user = str;
 662                 pwd = strchr(str, ':');
 663                 *pwd++ = '\0';
 664                 r = _http_basic_auth(conn, hdr, user, pwd);
 665                 free(str);
 666                 return (r);
 667         }
 668         return (-1);
 669 }
 670
 671
 672 /*****************************************************************************
 673  * Helper functions for connecting to a server or proxy
 674  */
 675
 676 /*
 677  * Connect to the correct HTTP server or proxy.
 678  */
 679 static conn_t *
 680 _http_connect(struct url *URL, struct url *purl, const char *flags)
 681 {
 682         conn_t *conn;
 683         int verbose;
 684         int af;
 685
 686 #ifdef INET6
 687         af = AF_UNSPEC;
 688 #else
 689         af = AF_INET;
 690 #endif
 691
 692         verbose = CHECK_FLAG('v');
 693         if (CHECK_FLAG('4'))
 694                 af = AF_INET;
 695 #ifdef INET6
 696         else if (CHECK_FLAG('6'))
 697                 af = AF_INET6;
 698 #endif
 699
 700         if (purl && strcasecmp(URL->scheme, SCHEME_HTTPS) != 0) {
 701                 URL = purl;
 702         } else if (strcasecmp(URL->scheme, SCHEME_FTP) == 0) {
 703                 /* can't talk http to an ftp server */
 704                 /* XXX should set an error code */
 705                 return (NULL);
 706         }
 707
 708         if ((conn = _fetch_connect(URL->host, URL->port, af, verbose)) == NULL)
 709                 /* _fetch_connect() has already set an error code */
 710                 return (NULL);
 711         if (strcasecmp(URL->scheme, SCHEME_HTTPS) == 0 &&
 712             _fetch_ssl(conn, verbose) == -1) {
 713                 _fetch_close(conn);
 714                 /* grrr */
 715                 errno = EAUTH;
 716                 _fetch_syserr();
 717                 return (NULL);
 718         }
 719
 720 #ifdef TCP_NOPUSH
 721         {
 722                 int     val;
 723
 724                 val = 1;
 725                 setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val, sizeof(val));
 726         }
 727 #endif
 728
 729         return (conn);
 730 }
 731
 732 static struct url *
 733 _http_get_proxy(const char *flags)
 734 {
 735         struct url *purl;
 736         char *p;
 737
 738         if (flags != NULL && strchr(flags, 'd') != NULL)
 739                 return (NULL);
 740         if (((p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
 741             *p && (purl = fetchParseURL(p))) {
 742                 if (!*purl->scheme)
 743                         strcpy(purl->scheme, SCHEME_HTTP);
 744                 if (!purl->port)
 745                         purl->port = _fetch_default_proxy_port(purl->scheme);
 746                 if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
 747                         return (purl);
 748                 fetchFreeURL(purl);
 749         }
 750         return (NULL);
 751 }
 752
 753 static void
 754 _http_print_html(FILE *out, FILE *in)
 755 {
 756         size_t len;
 757         char *line, *p, *q;
 758         int comment, tag;
 759
 760         comment = tag = 0;
 761         while ((line = fgetln(in, &len)) != NULL) {
 762                 while (len && isspace((unsigned)line[len - 1]))
 763                         --len;
 764                 for (p = q = line; q < line + len; ++q) {
 765                         if (comment && *q == '-') {
 766                                 if (q + 2 < line + len &&
 767                                     strcmp(q, "-->") == 0) {
 768                                         tag = comment = 0;
 769                                         q += 2;
 770                                 }
 771                         } else if (tag && !comment && *q == '>') {
 772                                 p = q + 1;
 773                                 tag = 0;
 774                         } else if (!tag && *q == '<') {
 775                                 if (q > p)
 776                                         fwrite(p, (unsigned)(q - p), 1, out);
 777                                 tag = 1;
 778                                 if (q + 3 < line + len &&
 779                                     strcmp(q, "<!--") == 0) {
 780                                         comment = 1;
 781                                         q += 3;
 782                                 }
 783                         }
 784                 }
 785                 if (!tag && q > p)
 786                         fwrite(p, (unsigned)(q - p), 1, out);
 787                 fputc('\n', out);
 788         }
 789 }
 790
 791
 792 /*****************************************************************************
 793  * Core
 794  */
 795
 796 /*
 797  * Send a request and process the reply
 798  *
 799  * XXX This function is way too long, the do..while loop should be split
 800  * XXX off into a separate function.
 801  */
 802 FILE *
 803 _http_request(struct url *URL, const char *op, struct url_stat *us,
 804     struct url *purl, const char *flags)
 805 {
 806         conn_t *conn;
 807         struct url *url, *new;
 808         int chunked, direct, need_auth, noredirect, verbose;
 809         int e, i, n, val;
 810         off_t offset, clength, length, size;
 811         time_t mtime;
 812         const char *p;
 813         FILE *f;
 814         hdr_t h;
 815         char hbuf[MAXHOSTNAMELEN + 7], *host;
 816
 817         direct = CHECK_FLAG('d');
 818         noredirect = CHECK_FLAG('A');
 819         verbose = CHECK_FLAG('v');
 820
 821         if (direct && purl) {
 822                 fetchFreeURL(purl);
 823                 purl = NULL;
 824         }
 825
 826         /* try the provided URL first */
 827         url = URL;
 828
 829         /* if the A flag is set, we only get one try */
 830         n = noredirect ? 1 : MAX_REDIRECT;
 831         i = 0;
 832
 833         e = HTTP_PROTOCOL_ERROR;
 834         need_auth = 0;
 835         do {
 836                 new = NULL;
 837                 chunked = 0;
 838                 offset = 0;
 839                 clength = -1;
 840                 length = -1;
 841                 size = -1;
 842                 mtime = 0;
 843
 844                 /* check port */
 845                 if (!url->port)
 846                         url->port = _fetch_default_port(url->scheme);
 847
 848                 /* were we redirected to an FTP URL? */
 849                 if (purl == NULL && strcmp(url->scheme, SCHEME_FTP) == 0) {
 850                         if (strcmp(op, "GET") == 0)
 851                                 return (_ftp_request(url, "RETR", us, purl, flags));
 852                         else if (strcmp(op, "HEAD") == 0)
 853                                 return (_ftp_request(url, "STAT", us, purl, flags));
 854                 }
 855
 856                 /* connect to server or proxy */
 857                 if ((conn = _http_connect(url, purl, flags)) == NULL)
 858                         goto ouch;
 859
 860                 host = url->host;
 861 #ifdef INET6
 862                 if (strchr(url->host, ':')) {
 863                         snprintf(hbuf, sizeof(hbuf), "[%s]", url->host);
 864                         host = hbuf;
 865                 }
 866 #endif
 867                 if (url->port != _fetch_default_port(url->scheme)) {
 868                         if (host != hbuf) {
 869                                 strcpy(hbuf, host);
 870                                 host = hbuf;
 871                         }
 872                         snprintf(hbuf + strlen(hbuf),
 873                             sizeof(hbuf) - strlen(hbuf), ":%d", url->port);
 874                 }
 875
 876                 /* send request */
 877                 if (verbose)
 878                         _fetch_info("requesting %s://%s%s",
 879                             url->scheme, host, url->doc);
 880                 if (purl) {
 881                         _http_cmd(conn, "%s %s://%s%s HTTP/1.1",
 882                             op, url->scheme, host, url->doc);
 883                 } else {
 884                         _http_cmd(conn, "%s %s HTTP/1.1",
 885                             op, url->doc);
 886                 }
 887
 888                 /* virtual host */
 889                 _http_cmd(conn, "Host: %s", host);
 890
 891                 /* proxy authorization */
 892                 if (purl) {
 893                         if (*purl->user || *purl->pwd)
 894                                 _http_basic_auth(conn, "Proxy-Authorization",
 895                                     purl->user, purl->pwd);
 896                         else if ((p = getenv("HTTP_PROXY_AUTH")) != NULL && *p != '\0')
 897                                 _http_authorize(conn, "Proxy-Authorization", p);
 898                 }
 899
 900                 /* server authorization */
 901                 if (need_auth || *url->user || *url->pwd) {
 902                         if (*url->user || *url->pwd)
 903                                 _http_basic_auth(conn, "Authorization", url->user, url->pwd);
 904                         else if ((p = getenv("HTTP_AUTH")) != NULL && *p != '\0')
 905                                 _http_authorize(conn, "Authorization", p);
 906                         else if (fetchAuthMethod && fetchAuthMethod(url) == 0) {
 907                                 _http_basic_auth(conn, "Authorization", url->user, url->pwd);
 908                         } else {
 909                                 _http_seterr(HTTP_NEED_AUTH);
 910                                 goto ouch;
 911                         }
 912                 }
 913
 914                 /* other headers */
 915                 if ((p = getenv("HTTP_REFERER")) != NULL && *p != '\0') {
 916                         if (strcasecmp(p, "auto") == 0)
 917                                 _http_cmd(conn, "Referer: %s://%s%s",
 918                                     url->scheme, host, url->doc);
 919                         else
 920                                 _http_cmd(conn, "Referer: %s", p);
 921                 }
 922                 if ((p = getenv("HTTP_USER_AGENT")) != NULL && *p != '\0')
 923                         _http_cmd(conn, "User-Agent: %s", p);
 924                 else
 925                         _http_cmd(conn, "User-Agent: %s " _LIBFETCH_VER, getprogname());
 926                 if (url->offset > 0)
 927                         _http_cmd(conn, "Range: bytes=%lld-", (long long)url->offset);
 928                 _http_cmd(conn, "Connection: close");
 929                 _http_cmd(conn, "");
 930
 931                 /*
 932                  * Force the queued request to be dispatched.  Normally, one
 933                  * would do this with shutdown(2) but squid proxies can be
 934                  * configured to disallow such half-closed connections.  To
 935                  * be compatible with such configurations, fiddle with socket
 936                  * options to force the pending data to be written.
 937                  */
 938                 val = 0;
 939 #ifdef TCP_NOPUSH
 940                 setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val,
 941                            sizeof(val));
 942 #endif
 943                 val = 1;
 944                 setsockopt(conn->sd, IPPROTO_TCP, TCP_NODELAY, &val,
 945                            sizeof(val));
 946
 947                 /* get reply */
 948                 switch (_http_get_reply(conn)) {
 949                 case HTTP_OK:
 950                 case HTTP_PARTIAL:
 951                         /* fine */
 952                         break;
 953                 case HTTP_MOVED_PERM:
 954                 case HTTP_MOVED_TEMP:
 955                 case HTTP_SEE_OTHER:
 956                         /*
 957                          * Not so fine, but we still have to read the
 958                          * headers to get the new location.
 959                          */
 960                         break;
 961                 case HTTP_NEED_AUTH:
 962                         if (need_auth) {
 963                                 /*
 964                                  * We already sent out authorization code,
 965                                  * so there's nothing more we can do.
 966                                  */
 967                                 _http_seterr(conn->err);
 968                                 goto ouch;
 969                         }
 970                         /* try again, but send the password this time */
 971                         if (verbose)
 972                                 _fetch_info("server requires authorization");
 973                         break;
 974                 case HTTP_NEED_PROXY_AUTH:
 975                         /*
 976                          * If we're talking to a proxy, we already sent
 977                          * our proxy authorization code, so there's
 978                          * nothing more we can do.
 979                          */
 980                         _http_seterr(conn->err);
 981                         goto ouch;
 982                 case HTTP_BAD_RANGE:
 983                         /*
 984                          * This can happen if we ask for 0 bytes because
 985                          * we already have the whole file.  Consider this
 986                          * a success for now, and check sizes later.
 987                          */
 988                         break;
 989                 case HTTP_PROTOCOL_ERROR:
 990                         /* fall through */
 991                 case -1:
 992                         _fetch_syserr();
 993                         goto ouch;
 994                 default:
 995                         _http_seterr(conn->err);
 996                         if (!verbose)
 997                                 goto ouch;
 998                         /* fall through so we can get the full error message */
 999                 }
1000
1001                 /* get headers */
1002                 do {
1003                         switch ((h = _http_next_header(conn, &p))) {
1004                         case hdr_syserror:
1005                                 _fetch_syserr();
1006                                 goto ouch;
1007                         case hdr_error:
1008                                 _http_seterr(HTTP_PROTOCOL_ERROR);
1009                                 goto ouch;
1010                         case hdr_content_length:
1011                                 _http_parse_length(p, &clength);
1012                                 break;
1013                         case hdr_content_range:
1014                                 _http_parse_range(p, &offset, &length, &size);
1015                                 break;
1016                         case hdr_last_modified:
1017                                 _http_parse_mtime(p, &mtime);
1018                                 break;
1019                         case hdr_location:
1020                                 if (!HTTP_REDIRECT(conn->err))
1021                                         break;
1022                                 if (new)
1023                                         free(new);
1024                                 if (verbose)
1025                                         _fetch_info("%d redirect to %s", conn->err, p);
1026                                 if (*p == '/')
1027                                         /* absolute path */
1028                                         new = fetchMakeURL(url->scheme, url->host, url->port, p,
1029                                             url->user, url->pwd);
1030                                 else
1031                                         new = fetchParseURL(p);
1032                                 if (new == NULL) {
1033                                         /* XXX should set an error code */
1034                                         DEBUG(fprintf(stderr, "failed to parse new URL\n"));
1035                                         goto ouch;
1036                                 }
1037                                 if (!*new->user && !*new->pwd) {
1038                                         strcpy(new->user, url->user);
1039                                         strcpy(new->pwd, url->pwd);
1040                                 }
1041                                 new->offset = url->offset;
1042                                 new->length = url->length;
1043                                 break;
1044                         case hdr_transfer_encoding:
1045                                 /* XXX weak test*/
1046                                 chunked = (strcasecmp(p, "chunked") == 0);
1047                                 break;
1048                         case hdr_www_authenticate:
1049                                 if (conn->err != HTTP_NEED_AUTH)
1050                                         break;
1051                                 /* if we were smarter, we'd check the method and realm */
1052                                 break;
1053                         case hdr_end:
1054                                 /* fall through */
1055                         case hdr_unknown:
1056                                 /* ignore */
1057                                 break;
1058                         }
1059                 } while (h > hdr_end);
1060
1061                 /* we need to provide authentication */
1062                 if (conn->err == HTTP_NEED_AUTH) {
1063                         e = conn->err;
1064                         need_auth = 1;
1065                         _fetch_close(conn);
1066                         conn = NULL;
1067                         continue;
1068                 }
1069
1070                 /* requested range not satisfiable */
1071                 if (conn->err == HTTP_BAD_RANGE) {
1072                         if (url->offset == size && url->length == 0) {
1073                                 /* asked for 0 bytes; fake it */
1074                                 offset = url->offset;
1075                                 conn->err = HTTP_OK;
1076                                 break;
1077                         } else {
1078                                 _http_seterr(conn->err);
1079                                 goto ouch;
1080                         }
1081                 }
1082
1083                 /* we have a hit or an error */
1084                 if (conn->err == HTTP_OK || conn->err == HTTP_PARTIAL || HTTP_ERROR(conn->err))
1085                         break;
1086
1087                 /* all other cases: we got a redirect */
1088                 e = conn->err;
1089                 need_auth = 0;
1090                 _fetch_close(conn);
1091                 conn = NULL;
1092                 if (!new) {
1093                         DEBUG(fprintf(stderr, "redirect with no new location\n"));
1094                         break;
1095                 }
1096                 if (url != URL)
1097                         fetchFreeURL(url);
1098                 url = new;
1099         } while (++i < n);
1100
1101         /* we failed, or ran out of retries */
1102         if (conn == NULL) {
1103                 _http_seterr(e);
1104                 goto ouch;
1105         }
1106
1107         DEBUG(fprintf(stderr, "offset %lld, length %lld,"
1108                   " size %lld, clength %lld\n",
1109                   (long long)offset, (long long)length,
1110                   (long long)size, (long long)clength));
1111
1112         /* check for inconsistencies */
1113         if (clength != -1 && length != -1 && clength != length) {
1114                 _http_seterr(HTTP_PROTOCOL_ERROR);
1115                 goto ouch;
1116         }
1117         if (clength == -1)
1118                 clength = length;
1119         if (clength != -1)
1120                 length = offset + clength;
1121         if (length != -1 && size != -1 && length != size) {
1122                 _http_seterr(HTTP_PROTOCOL_ERROR);
1123                 goto ouch;
1124         }
1125         if (size == -1)
1126                 size = length;
1127
1128         /* fill in stats */
1129         if (us) {
1130                 us->size = size;
1131                 us->atime = us->mtime = mtime;
1132         }
1133
1134         /* too far? */
1135         if (URL->offset > 0 && offset > URL->offset) {
1136                 _http_seterr(HTTP_PROTOCOL_ERROR);
1137                 goto ouch;
1138         }
1139
1140         /* report back real offset and size */
1141         URL->offset = offset;
1142         URL->length = (unsigned) clength;
1143
1144         /* wrap it up in a FILE */
1145         if ((f = _http_funopen(conn, chunked)) == NULL) {
1146                 _fetch_syserr();
1147                 goto ouch;
1148         }
1149
1150         if (url != URL)
1151                 fetchFreeURL(url);
1152         if (purl)
1153                 fetchFreeURL(purl);
1154
1155         if (HTTP_ERROR(conn->err)) {
1156                 _http_print_html(stderr, f);
1157                 fclose(f);
1158                 f = NULL;
1159         }
1160
1161         return (f);
1162
1163 ouch:
1164         if (url != URL)
1165                 fetchFreeURL(url);
1166         if (purl)
1167                 fetchFreeURL(purl);
1168         if (conn != NULL)
1169                 _fetch_close(conn);
1170         return (NULL);
1171 }
1172
1173
1174 /*****************************************************************************
1175  * Entry points
1176  */
1177
1178 /*
1179  * Retrieve and stat a file by HTTP
1180  */
1181 FILE *
1182 fetchXGetHTTP(struct url *URL, struct url_stat *us, const char *flags)
1183 {
1184         return (_http_request(URL, "GET", us, _http_get_proxy(flags), flags));
1185 }
1186
1187 /*
1188  * Retrieve a file by HTTP
1189  */
1190 FILE *
1191 fetchGetHTTP(struct url *URL, const char *flags)
1192 {
1193         return (fetchXGetHTTP(URL, NULL, flags));
1194 }
1195
1196 /*
1197  * Store a file by HTTP
1198  */
1199 /* ARGSUSED0 */
1200 FILE *
1201 fetchPutHTTP(struct url *URL __unused, const char *flags __unused)
1202 {
1203         warnx("fetchPutHTTP(): not implemented");
1204         return (NULL);
1205 }
1206
1207 /*
1208  * Get an HTTP document's metadata
1209  */
1210 int
1211 fetchStatHTTP(struct url *URL, struct url_stat *us, const char *flags)
1212 {
1213         FILE *f;
1214
1215         f = _http_request(URL, "HEAD", us, _http_get_proxy(flags), flags);
1216         if (f == NULL)
1217                 return (-1);
1218         fclose(f);
1219         return (0);
1220 }
1221
1222 /*
1223  * List a directory
1224  */
1225 /* ARGSUSED0 */
1226 struct url_ent *
1227 fetchListHTTP(struct url *url __unused, const char *flags __unused)
1228 {
1229         warnx("fetchListHTTP(): not implemented");
1230         return (NULL);
1231 }