lib/libfetch/ftp.c

   1 /*-
   2  * Copyright (c) 1998-2004 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  * $FreeBSD: src/lib/libfetch/ftp.c,v 1.96 2007/04/22 22:33:29 njl Exp $
  29  * $DragonFly: src/lib/libfetch/ftp.c,v 1.4 2007/08/05 21:48:12 swildner Exp $
  30  */
  31
  32 /*
  33  * Portions of this code were taken from or based on ftpio.c:
  34  *
  35  * ----------------------------------------------------------------------------
  36  * "THE BEER-WARE LICENSE" (Revision 42):
  37  * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
  38  * can do whatever you want with this stuff. If we meet some day, and you think
  39  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
  40  * ----------------------------------------------------------------------------
  41  *
  42  * Major Changelog:
  43  *
  44  * Dag-Erling Coïdan Smørgrav
  45  * 9 Jun 1998
  46  *
  47  * Incorporated into libfetch
  48  *
  49  * Jordan K. Hubbard
  50  * 17 Jan 1996
  51  *
  52  * Turned inside out. Now returns xfers as new file ids, not as a special
  53  * `state' of FTP_t
  54  *
  55  * $ftpioId: ftpio.c,v 1.30 1998/04/11 07:28:53 phk Exp $
  56  *
  57  */
  58
  59 #include <sys/param.h>
  60 #include <sys/socket.h>
  61 #include <netinet/in.h>
  62
  63 #include <ctype.h>
  64 #include <err.h>
  65 #include <errno.h>
  66 #include <fcntl.h>
  67 #include <netdb.h>
  68 #include <stdarg.h>
  69 #include <stdint.h>
  70 #include <stdio.h>
  71 #include <stdlib.h>
  72 #include <string.h>
  73 #include <time.h>
  74 #include <unistd.h>
  75
  76 #include "fetch.h"
  77 #include "common.h"
  78 #include "ftperr.h"
  79
  80 #define FTP_ANONYMOUS_USER      "anonymous"
  81
  82 #define FTP_CONNECTION_ALREADY_OPEN     125
  83 #define FTP_OPEN_DATA_CONNECTION        150
  84 #define FTP_OK                          200
  85 #define FTP_FILE_STATUS                 213
  86 #define FTP_SERVICE_READY               220
  87 #define FTP_TRANSFER_COMPLETE           226
  88 #define FTP_PASSIVE_MODE                227
  89 #define FTP_LPASSIVE_MODE               228
  90 #define FTP_EPASSIVE_MODE               229
  91 #define FTP_LOGGED_IN                   230
  92 #define FTP_FILE_ACTION_OK              250
  93 #define FTP_DIRECTORY_CREATED           257 /* multiple meanings */
  94 #define FTP_FILE_CREATED                257 /* multiple meanings */
  95 #define FTP_WORKING_DIRECTORY           257 /* multiple meanings */
  96 #define FTP_NEED_PASSWORD               331
  97 #define FTP_NEED_ACCOUNT                332
  98 #define FTP_FILE_OK                     350
  99 #define FTP_SYNTAX_ERROR                500
 100 #define FTP_PROTOCOL_ERROR              999
 101
 102 static struct url cached_host;
 103 static conn_t   *cached_connection;
 104
 105 #define isftpreply(foo) (isdigit(foo[0]) && isdigit(foo[1]) \
 106                          && isdigit(foo[2]) \
 107                          && (foo[3] == ' ' || foo[3] == '\0'))
 108 #define isftpinfo(foo) (isdigit(foo[0]) && isdigit(foo[1]) \
 109                         && isdigit(foo[2]) && foo[3] == '-')
 110
 111 /*
 112  * Translate IPv4 mapped IPv6 address to IPv4 address
 113  */
 114 static void
 115 unmappedaddr(struct sockaddr_in6 *sin6)
 116 {
 117         struct sockaddr_in *sin4;
 118         u_int32_t addr;
 119         int port;
 120
 121         if (sin6->sin6_family != AF_INET6 ||
 122             !IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
 123                 return;
 124         sin4 = (struct sockaddr_in *)sin6;
 125         addr = *(u_int32_t *)&sin6->sin6_addr.s6_addr[12];
 126         port = sin6->sin6_port;
 127         memset(sin4, 0, sizeof(struct sockaddr_in));
 128         sin4->sin_addr.s_addr = addr;
 129         sin4->sin_port = port;
 130         sin4->sin_family = AF_INET;
 131         sin4->sin_len = sizeof(struct sockaddr_in);
 132 }
 133
 134 /*
 135  * Get server response
 136  */
 137 static int
 138 _ftp_chkerr(conn_t *conn)
 139 {
 140         if (_fetch_getln(conn) == -1) {
 141                 _fetch_syserr();
 142                 return (-1);
 143         }
 144         if (isftpinfo(conn->buf)) {
 145                 while (conn->buflen && !isftpreply(conn->buf)) {
 146                         if (_fetch_getln(conn) == -1) {
 147                                 _fetch_syserr();
 148                                 return (-1);
 149                         }
 150                 }
 151         }
 152
 153         while (conn->buflen && isspace(conn->buf[conn->buflen - 1]))
 154                 conn->buflen--;
 155         conn->buf[conn->buflen] = '\0';
 156
 157         if (!isftpreply(conn->buf)) {
 158                 _ftp_seterr(FTP_PROTOCOL_ERROR);
 159                 return (-1);
 160         }
 161
 162         conn->err = (conn->buf[0] - '0') * 100
 163             + (conn->buf[1] - '0') * 10
 164             + (conn->buf[2] - '0');
 165
 166         return (conn->err);
 167 }
 168
 169 /*
 170  * Send a command and check reply
 171  */
 172 static int
 173 _ftp_cmd(conn_t *conn, const char *fmt, ...)
 174 {
 175         va_list ap;
 176         size_t len;
 177         char *msg;
 178         int r;
 179
 180         va_start(ap, fmt);
 181         len = vasprintf(&msg, fmt, ap);
 182         va_end(ap);
 183
 184         if (msg == NULL) {
 185                 errno = ENOMEM;
 186                 _fetch_syserr();
 187                 return (-1);
 188         }
 189
 190         r = _fetch_putln(conn, msg, len);
 191         free(msg);
 192
 193         if (r == -1) {
 194                 _fetch_syserr();
 195                 return (-1);
 196         }
 197
 198         return (_ftp_chkerr(conn));
 199 }
 200
 201 /*
 202  * Return a pointer to the filename part of a path
 203  */
 204 static const char *
 205 _ftp_filename(const char *file, int *len, int *type)
 206 {
 207         const char *s;
 208
 209         if ((s = strrchr(file, '/')) == NULL)
 210                 s = file;
 211         else
 212                 s = s + 1;
 213         *len = strlen(s);
 214         if (*len > 7 && strncmp(s + *len - 7, ";type=", 6) == 0) {
 215                 *type = s[*len - 1];
 216                 *len -= 7;
 217         } else {
 218                 *type = '\0';
 219         }
 220         return (s);
 221 }
 222
 223 /*
 224  * Get current working directory from the reply to a CWD, PWD or CDUP
 225  * command.
 226  */
 227 static int
 228 _ftp_pwd(conn_t *conn, char *pwd, size_t pwdlen)
 229 {
 230         char *src, *dst, *end;
 231         int q;
 232
 233         if (conn->err != FTP_WORKING_DIRECTORY &&
 234             conn->err != FTP_FILE_ACTION_OK)
 235                 return (FTP_PROTOCOL_ERROR);
 236         end = conn->buf + conn->buflen;
 237         src = conn->buf + 4;
 238         if (src >= end || *src++ != '"')
 239                 return (FTP_PROTOCOL_ERROR);
 240         for (q = 0, dst = pwd; src < end && pwdlen--; ++src) {
 241                 if (!q && *src == '"')
 242                         q = 1;
 243                 else if (q && *src != '"')
 244                         break;
 245                 else if (q)
 246                         *dst++ = '"', q = 0;
 247                 else
 248                         *dst++ = *src;
 249         }
 250         if (!pwdlen)
 251                 return (FTP_PROTOCOL_ERROR);
 252         *dst = '\0';
 253 #if 0
 254         DEBUG(fprintf(stderr, "pwd: [%s]\n", pwd));
 255 #endif
 256         return (FTP_OK);
 257 }
 258
 259 /*
 260  * Change working directory to the directory that contains the specified
 261  * file.
 262  */
 263 static int
 264 _ftp_cwd(conn_t *conn, const char *file)
 265 {
 266         const char *beg, *end;
 267         char pwd[PATH_MAX];
 268         int e, i, len;
 269
 270         /* If no slashes in name, no need to change dirs. */
 271         if ((end = strrchr(file, '/')) == NULL)
 272                 return (0);
 273         if ((e = _ftp_cmd(conn, "PWD")) != FTP_WORKING_DIRECTORY ||
 274             (e = _ftp_pwd(conn, pwd, sizeof(pwd))) != FTP_OK) {
 275                 _ftp_seterr(e);
 276                 return (-1);
 277         }
 278         for (;;) {
 279                 len = strlen(pwd);
 280
 281                 /* Look for a common prefix between PWD and dir to fetch. */
 282                 for (i = 0; i <= len && i <= end - file; ++i)
 283                         if (pwd[i] != file[i])
 284                                 break;
 285 #if 0
 286                 DEBUG(fprintf(stderr, "have: [%.*s|%s]\n", i, pwd, pwd + i));
 287                 DEBUG(fprintf(stderr, "want: [%.*s|%s]\n", i, file, file + i));
 288 #endif
 289                 /* Keep going up a dir until we have a matching prefix. */
 290                 if (pwd[i] == '\0' && (file[i - 1] == '/' || file[i] == '/'))
 291                         break;
 292                 if ((e = _ftp_cmd(conn, "CDUP")) != FTP_FILE_ACTION_OK ||
 293                     (e = _ftp_cmd(conn, "PWD")) != FTP_WORKING_DIRECTORY ||
 294                     (e = _ftp_pwd(conn, pwd, sizeof(pwd))) != FTP_OK) {
 295                         _ftp_seterr(e);
 296                         return (-1);
 297                 }
 298         }
 299
 300 #ifdef FTP_COMBINE_CWDS
 301         /* Skip leading slashes, even "////". */
 302         for (beg = file + i; beg < end && *beg == '/'; ++beg, ++i)
 303                 /* nothing */ ;
 304
 305         /* If there is no trailing dir, we're already there. */
 306         if (beg >= end)
 307                 return (0);
 308
 309         /* Change to the directory all in one chunk (e.g., foo/bar/baz). */
 310         e = _ftp_cmd(conn, "CWD %.*s", (int)(end - beg), beg);
 311         if (e == FTP_FILE_ACTION_OK)
 312                 return (0);
 313 #endif /* FTP_COMBINE_CWDS */
 314
 315         /* That didn't work so go back to legacy behavior (multiple CWDs). */
 316         for (beg = file + i; beg < end; beg = file + i + 1) {
 317                 while (*beg == '/')
 318                         ++beg, ++i;
 319                 for (++i; file + i < end && file[i] != '/'; ++i)
 320                         /* nothing */ ;
 321                 e = _ftp_cmd(conn, "CWD %.*s", file + i - beg, beg);
 322                 if (e != FTP_FILE_ACTION_OK) {
 323                         _ftp_seterr(e);
 324                         return (-1);
 325                 }
 326         }
 327         return (0);
 328 }
 329
 330 /*
 331  * Set transfer mode and data type
 332  */
 333 static int
 334 _ftp_mode_type(conn_t *conn, int mode, int type)
 335 {
 336         int e;
 337
 338         switch (mode) {
 339         case 0:
 340         case 's':
 341                 mode = 'S';
 342         case 'S':
 343                 break;
 344         default:
 345                 return (FTP_PROTOCOL_ERROR);
 346         }
 347         if ((e = _ftp_cmd(conn, "MODE %c", mode)) != FTP_OK) {
 348                 if (mode == 'S') {
 349                         /*
 350                          * Stream mode is supposed to be the default - so
 351                          * much so that some servers not only do not
 352                          * support any other mode, but do not support the
 353                          * MODE command at all.
 354                          *
 355                          * If "MODE S" fails, it is unlikely that we
 356                          * previously succeeded in setting a different
 357                          * mode.  Therefore, we simply hope that the
 358                          * server is already in the correct mode, and
 359                          * silently ignore the failure.
 360                          */
 361                 } else {
 362                         return (e);
 363                 }
 364         }
 365
 366         switch (type) {
 367         case 0:
 368         case 'i':
 369                 type = 'I';
 370         case 'I':
 371                 break;
 372         case 'a':
 373                 type = 'A';
 374         case 'A':
 375                 break;
 376         case 'd':
 377                 type = 'D';
 378         case 'D':
 379                 /* can't handle yet */
 380         default:
 381                 return (FTP_PROTOCOL_ERROR);
 382         }
 383         if ((e = _ftp_cmd(conn, "TYPE %c", type)) != FTP_OK)
 384                 return (e);
 385
 386         return (FTP_OK);
 387 }
 388
 389 /*
 390  * Request and parse file stats
 391  */
 392 static int
 393 _ftp_stat(conn_t *conn, const char *file, struct url_stat *us)
 394 {
 395         char *ln;
 396         const char *filename;
 397         int filenamelen, type;
 398         struct tm tm;
 399         time_t t;
 400         int e;
 401
 402         us->size = -1;
 403         us->atime = us->mtime = 0;
 404
 405         filename = _ftp_filename(file, &filenamelen, &type);
 406
 407         if ((e = _ftp_mode_type(conn, 0, type)) != FTP_OK) {
 408                 _ftp_seterr(e);
 409                 return (-1);
 410         }
 411
 412         e = _ftp_cmd(conn, "SIZE %.*s", filenamelen, filename);
 413         if (e != FTP_FILE_STATUS) {
 414                 _ftp_seterr(e);
 415                 return (-1);
 416         }
 417         for (ln = conn->buf + 4; *ln && isspace(*ln); ln++)
 418                 /* nothing */ ;
 419         for (us->size = 0; *ln && isdigit(*ln); ln++)
 420                 us->size = us->size * 10 + *ln - '0';
 421         if (*ln && !isspace(*ln)) {
 422                 _ftp_seterr(FTP_PROTOCOL_ERROR);
 423                 us->size = -1;
 424                 return (-1);
 425         }
 426         if (us->size == 0)
 427                 us->size = -1;
 428         DEBUG(fprintf(stderr, "size: [%lld]\n", (long long)us->size));
 429
 430         e = _ftp_cmd(conn, "MDTM %.*s", filenamelen, filename);
 431         if (e != FTP_FILE_STATUS) {
 432                 _ftp_seterr(e);
 433                 return (-1);
 434         }
 435         for (ln = conn->buf + 4; *ln && isspace(*ln); ln++)
 436                 /* nothing */ ;
 437         switch (strspn(ln, "0123456789")) {
 438         case 14:
 439                 break;
 440         case 15:
 441                 ln++;
 442                 ln[0] = '2';
 443                 ln[1] = '0';
 444                 break;
 445         default:
 446                 _ftp_seterr(FTP_PROTOCOL_ERROR);
 447                 return (-1);
 448         }
 449         if (sscanf(ln, "%04d%02d%02d%02d%02d%02d",
 450             &tm.tm_year, &tm.tm_mon, &tm.tm_mday,
 451             &tm.tm_hour, &tm.tm_min, &tm.tm_sec) != 6) {
 452                 _ftp_seterr(FTP_PROTOCOL_ERROR);
 453                 return (-1);
 454         }
 455         tm.tm_mon--;
 456         tm.tm_year -= 1900;
 457         tm.tm_isdst = -1;
 458         t = timegm(&tm);
 459         if (t == (time_t)-1)
 460                 t = time(NULL);
 461         us->mtime = t;
 462         us->atime = t;
 463         DEBUG(fprintf(stderr,
 464             "last modified: [%04d-%02d-%02d %02d:%02d:%02d]\n",
 465             tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 466             tm.tm_hour, tm.tm_min, tm.tm_sec));
 467         return (0);
 468 }
 469
 470 /*
 471  * I/O functions for FTP
 472  */
 473 struct ftpio {
 474         conn_t  *cconn;         /* Control connection */
 475         conn_t  *dconn;         /* Data connection */
 476         int      dir;           /* Direction */
 477         int      eof;           /* EOF reached */
 478         int      err;           /* Error code */
 479 };
 480
 481 static int       _ftp_readfn(void *, char *, int);
 482 static int       _ftp_writefn(void *, const char *, int);
 483 static fpos_t    _ftp_seekfn(void *, fpos_t, int);
 484 static int       _ftp_closefn(void *);
 485
 486 static int
 487 _ftp_readfn(void *v, char *buf, int len)
 488 {
 489         struct ftpio *io;
 490         int r;
 491
 492         io = (struct ftpio *)v;
 493         if (io == NULL) {
 494                 errno = EBADF;
 495                 return (-1);
 496         }
 497         if (io->cconn == NULL || io->dconn == NULL || io->dir == O_WRONLY) {
 498                 errno = EBADF;
 499                 return (-1);
 500         }
 501         if (io->err) {
 502                 errno = io->err;
 503                 return (-1);
 504         }
 505         if (io->eof)
 506                 return (0);
 507         r = _fetch_read(io->dconn, buf, len);
 508         if (r > 0)
 509                 return (r);
 510         if (r == 0) {
 511                 io->eof = 1;
 512                 return (0);
 513         }
 514         if (errno != EINTR)
 515                 io->err = errno;
 516         return (-1);
 517 }
 518
 519 static int
 520 _ftp_writefn(void *v, const char *buf, int len)
 521 {
 522         struct ftpio *io;
 523         int w;
 524
 525         io = (struct ftpio *)v;
 526         if (io == NULL) {
 527                 errno = EBADF;
 528                 return (-1);
 529         }
 530         if (io->cconn == NULL || io->dconn == NULL || io->dir == O_RDONLY) {
 531                 errno = EBADF;
 532                 return (-1);
 533         }
 534         if (io->err) {
 535                 errno = io->err;
 536                 return (-1);
 537         }
 538         w = _fetch_write(io->dconn, buf, len);
 539         if (w >= 0)
 540                 return (w);
 541         if (errno != EINTR)
 542                 io->err = errno;
 543         return (-1);
 544 }
 545
 546 static fpos_t
 547 _ftp_seekfn(void *v, fpos_t pos __unused, int whence __unused)
 548 {
 549         struct ftpio *io;
 550
 551         io = (struct ftpio *)v;
 552         if (io == NULL) {
 553                 errno = EBADF;
 554                 return (-1);
 555         }
 556         errno = ESPIPE;
 557         return (-1);
 558 }
 559
 560 static int
 561 _ftp_closefn(void *v)
 562 {
 563         struct ftpio *io;
 564         int r;
 565
 566         io = (struct ftpio *)v;
 567         if (io == NULL) {
 568                 errno = EBADF;
 569                 return (-1);
 570         }
 571         if (io->dir == -1)
 572                 return (0);
 573         if (io->cconn == NULL || io->dconn == NULL) {
 574                 errno = EBADF;
 575                 return (-1);
 576         }
 577         _fetch_close(io->dconn);
 578         io->dir = -1;
 579         io->dconn = NULL;
 580         DEBUG(fprintf(stderr, "Waiting for final status\n"));
 581         r = _ftp_chkerr(io->cconn);
 582         if (io->cconn == cached_connection && io->cconn->ref == 1)
 583                 cached_connection = NULL;
 584         _fetch_close(io->cconn);
 585         free(io);
 586         return (r == FTP_TRANSFER_COMPLETE) ? 0 : -1;
 587 }
 588
 589 static FILE *
 590 _ftp_setup(conn_t *cconn, conn_t *dconn, int mode)
 591 {
 592         struct ftpio *io;
 593         FILE *f;
 594
 595         if (cconn == NULL || dconn == NULL)
 596                 return (NULL);
 597         if ((io = malloc(sizeof(*io))) == NULL)
 598                 return (NULL);
 599         io->cconn = cconn;
 600         io->dconn = dconn;
 601         io->dir = mode;
 602         io->eof = io->err = 0;
 603         f = funopen(io, _ftp_readfn, _ftp_writefn, _ftp_seekfn, _ftp_closefn);
 604         if (f == NULL)
 605                 free(io);
 606         return (f);
 607 }
 608
 609 /*
 610  * Transfer file
 611  */
 612 static FILE *
 613 _ftp_transfer(conn_t *conn, const char *oper, const char *file,
 614     int mode, off_t offset, const char *flags)
 615 {
 616         struct sockaddr_storage sa;
 617         struct sockaddr_in6 *sin6;
 618         struct sockaddr_in *sin4;
 619         const char *bindaddr;
 620         const char *filename;
 621         int filenamelen, type;
 622         int low, pasv, verbose;
 623         int e, sd = -1;
 624         socklen_t l;
 625         char *s;
 626         FILE *df;
 627
 628         /* check flags */
 629         low = CHECK_FLAG('l');
 630         pasv = CHECK_FLAG('p');
 631         verbose = CHECK_FLAG('v');
 632
 633         /* passive mode */
 634         if (!pasv)
 635                 pasv = ((s = getenv("FTP_PASSIVE_MODE")) != NULL &&
 636                     strncasecmp(s, "no", 2) != 0);
 637
 638         /* isolate filename */
 639         filename = _ftp_filename(file, &filenamelen, &type);
 640
 641         /* set transfer mode and data type */
 642         if ((e = _ftp_mode_type(conn, 0, type)) != FTP_OK)
 643                 goto ouch;
 644
 645         /* find our own address, bind, and listen */
 646         l = sizeof(sa);
 647         if (getsockname(conn->sd, (struct sockaddr *)&sa, &l) == -1)
 648                 goto sysouch;
 649         if (sa.ss_family == AF_INET6)
 650                 unmappedaddr((struct sockaddr_in6 *)&sa);
 651
 652         /* open data socket */
 653         if ((sd = socket(sa.ss_family, SOCK_STREAM, IPPROTO_TCP)) == -1) {
 654                 _fetch_syserr();
 655                 return (NULL);
 656         }
 657
 658         if (pasv) {
 659                 u_char addr[64];
 660                 char *ln, *p;
 661                 unsigned int i;
 662                 int port;
 663
 664                 /* send PASV command */
 665                 if (verbose)
 666                         _fetch_info("setting passive mode");
 667                 switch (sa.ss_family) {
 668                 case AF_INET:
 669                         if ((e = _ftp_cmd(conn, "PASV")) != FTP_PASSIVE_MODE)
 670                                 goto ouch;
 671                         break;
 672                 case AF_INET6:
 673                         if ((e = _ftp_cmd(conn, "EPSV")) != FTP_EPASSIVE_MODE) {
 674                                 if (e == -1)
 675                                         goto ouch;
 676                                 if ((e = _ftp_cmd(conn, "LPSV")) !=
 677                                     FTP_LPASSIVE_MODE)
 678                                         goto ouch;
 679                         }
 680                         break;
 681                 default:
 682                         e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
 683                         goto ouch;
 684                 }
 685
 686                 /*
 687                  * Find address and port number. The reply to the PASV command
 688                  * is IMHO the one and only weak point in the FTP protocol.
 689                  */
 690                 ln = conn->buf;
 691                 switch (e) {
 692                 case FTP_PASSIVE_MODE:
 693                 case FTP_LPASSIVE_MODE:
 694                         for (p = ln + 3; *p && !isdigit(*p); p++)
 695                                 /* nothing */ ;
 696                         if (!*p) {
 697                                 e = FTP_PROTOCOL_ERROR;
 698                                 goto ouch;
 699                         }
 700                         l = (e == FTP_PASSIVE_MODE ? 6 : 21);
 701                         for (i = 0; *p && i < l; i++, p++)
 702                                 addr[i] = strtol(p, &p, 10);
 703                         if (i < l) {
 704                                 e = FTP_PROTOCOL_ERROR;
 705                                 goto ouch;
 706                         }
 707                         break;
 708                 case FTP_EPASSIVE_MODE:
 709                         for (p = ln + 3; *p && *p != '('; p++)
 710                                 /* nothing */ ;
 711                         if (!*p) {
 712                                 e = FTP_PROTOCOL_ERROR;
 713                                 goto ouch;
 714                         }
 715                         ++p;
 716                         if (sscanf(p, "%c%c%c%d%c", &addr[0], &addr[1], &addr[2],
 717                                 &port, &addr[3]) != 5 ||
 718                             addr[0] != addr[1] ||
 719                             addr[0] != addr[2] || addr[0] != addr[3]) {
 720                                 e = FTP_PROTOCOL_ERROR;
 721                                 goto ouch;
 722                         }
 723                         break;
 724                 }
 725
 726                 /* seek to required offset */
 727                 if (offset)
 728                         if (_ftp_cmd(conn, "REST %lu", (u_long)offset) != FTP_FILE_OK)
 729                                 goto sysouch;
 730
 731                 /* construct sockaddr for data socket */
 732                 l = sizeof(sa);
 733                 if (getpeername(conn->sd, (struct sockaddr *)&sa, &l) == -1)
 734                         goto sysouch;
 735                 if (sa.ss_family == AF_INET6)
 736                         unmappedaddr((struct sockaddr_in6 *)&sa);
 737                 switch (sa.ss_family) {
 738                 case AF_INET6:
 739                         sin6 = (struct sockaddr_in6 *)&sa;
 740                         if (e == FTP_EPASSIVE_MODE)
 741                                 sin6->sin6_port = htons(port);
 742                         else {
 743                                 bcopy(addr + 2, (char *)&sin6->sin6_addr, 16);
 744                                 bcopy(addr + 19, (char *)&sin6->sin6_port, 2);
 745                         }
 746                         break;
 747                 case AF_INET:
 748                         sin4 = (struct sockaddr_in *)&sa;
 749                         if (e == FTP_EPASSIVE_MODE)
 750                                 sin4->sin_port = htons(port);
 751                         else {
 752                                 bcopy(addr, (char *)&sin4->sin_addr, 4);
 753                                 bcopy(addr + 4, (char *)&sin4->sin_port, 2);
 754                         }
 755                         break;
 756                 default:
 757                         e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
 758                         break;
 759                 }
 760
 761                 /* connect to data port */
 762                 if (verbose)
 763                         _fetch_info("opening data connection");
 764                 bindaddr = getenv("FETCH_BIND_ADDRESS");
 765                 if (bindaddr != NULL && *bindaddr != '\0' &&
 766                     _fetch_bind(sd, sa.ss_family, bindaddr) != 0)
 767                         goto sysouch;
 768                 if (connect(sd, (struct sockaddr *)&sa, sa.ss_len) == -1)
 769                         goto sysouch;
 770
 771                 /* make the server initiate the transfer */
 772                 if (verbose)
 773                         _fetch_info("initiating transfer");
 774                 e = _ftp_cmd(conn, "%s %.*s", oper, filenamelen, filename);
 775                 if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
 776                         goto ouch;
 777
 778         } else {
 779                 u_int32_t a;
 780                 u_short p;
 781                 int arg, d;
 782                 char *ap;
 783                 char hname[INET6_ADDRSTRLEN];
 784
 785                 switch (sa.ss_family) {
 786                 case AF_INET6:
 787                         ((struct sockaddr_in6 *)&sa)->sin6_port = 0;
 788 #ifdef IPV6_PORTRANGE
 789                         arg = low ? IPV6_PORTRANGE_DEFAULT : IPV6_PORTRANGE_HIGH;
 790                         if (setsockopt(sd, IPPROTO_IPV6, IPV6_PORTRANGE,
 791                                 (char *)&arg, sizeof(arg)) == -1)
 792                                 goto sysouch;
 793 #endif
 794                         break;
 795                 case AF_INET:
 796                         ((struct sockaddr_in *)&sa)->sin_port = 0;
 797                         arg = low ? IP_PORTRANGE_DEFAULT : IP_PORTRANGE_HIGH;
 798                         if (setsockopt(sd, IPPROTO_IP, IP_PORTRANGE,
 799                                 (char *)&arg, sizeof(arg)) == -1)
 800                                 goto sysouch;
 801                         break;
 802                 }
 803                 if (verbose)
 804                         _fetch_info("binding data socket");
 805                 if (bind(sd, (struct sockaddr *)&sa, sa.ss_len) == -1)
 806                         goto sysouch;
 807                 if (listen(sd, 1) == -1)
 808                         goto sysouch;
 809
 810                 /* find what port we're on and tell the server */
 811                 if (getsockname(sd, (struct sockaddr *)&sa, &l) == -1)
 812                         goto sysouch;
 813                 switch (sa.ss_family) {
 814                 case AF_INET:
 815                         sin4 = (struct sockaddr_in *)&sa;
 816                         a = ntohl(sin4->sin_addr.s_addr);
 817                         p = ntohs(sin4->sin_port);
 818                         e = _ftp_cmd(conn, "PORT %d,%d,%d,%d,%d,%d",
 819                             (a >> 24) & 0xff, (a >> 16) & 0xff,
 820                             (a >> 8) & 0xff, a & 0xff,
 821                             (p >> 8) & 0xff, p & 0xff);
 822                         break;
 823                 case AF_INET6:
 824 #define UC(b)   (((int)b)&0xff)
 825                         e = -1;
 826                         sin6 = (struct sockaddr_in6 *)&sa;
 827                         sin6->sin6_scope_id = 0;
 828                         if (getnameinfo((struct sockaddr *)&sa, sa.ss_len,
 829                                 hname, sizeof(hname),
 830                                 NULL, 0, NI_NUMERICHOST) == 0) {
 831                                 e = _ftp_cmd(conn, "EPRT |%d|%s|%d|", 2, hname,
 832                                     htons(sin6->sin6_port));
 833                                 if (e == -1)
 834                                         goto ouch;
 835                         }
 836                         if (e != FTP_OK) {
 837                                 ap = (char *)&sin6->sin6_addr;
 838                                 e = _ftp_cmd(conn,
 839                                     "LPRT %d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d",
 840                                     6, 16,
 841                                     UC(ap[0]), UC(ap[1]), UC(ap[2]), UC(ap[3]),
 842                                     UC(ap[4]), UC(ap[5]), UC(ap[6]), UC(ap[7]),
 843                                     UC(ap[8]), UC(ap[9]), UC(ap[10]), UC(ap[11]),
 844                                     UC(ap[12]), UC(ap[13]), UC(ap[14]), UC(ap[15]),
 845                                     2,
 846                                     (ntohs(sin6->sin6_port) >> 8) & 0xff,
 847                                     ntohs(sin6->sin6_port)        & 0xff);
 848                         }
 849                         break;
 850                 default:
 851                         e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
 852                         goto ouch;
 853                 }
 854                 if (e != FTP_OK)
 855                         goto ouch;
 856
 857                 /* seek to required offset */
 858                 if (offset)
 859                         if (_ftp_cmd(conn, "REST %ju", (uintmax_t)offset) != FTP_FILE_OK)
 860                                 goto sysouch;
 861
 862                 /* make the server initiate the transfer */
 863                 if (verbose)
 864                         _fetch_info("initiating transfer");
 865                 e = _ftp_cmd(conn, "%s %.*s", oper, filenamelen, filename);
 866                 if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
 867                         goto ouch;
 868
 869                 /* accept the incoming connection and go to town */
 870                 if ((d = accept(sd, NULL, NULL)) == -1)
 871                         goto sysouch;
 872                 close(sd);
 873                 sd = d;
 874         }
 875
 876         if ((df = _ftp_setup(conn, _fetch_reopen(sd), mode)) == NULL)
 877                 goto sysouch;
 878         return (df);
 879
 880 sysouch:
 881         _fetch_syserr();
 882         if (sd >= 0)
 883                 close(sd);
 884         return (NULL);
 885
 886 ouch:
 887         if (e != -1)
 888                 _ftp_seterr(e);
 889         if (sd >= 0)
 890                 close(sd);
 891         return (NULL);
 892 }
 893
 894 /*
 895  * Authenticate
 896  */
 897 static int
 898 _ftp_authenticate(conn_t *conn, struct url *url, struct url *purl)
 899 {
 900         const char *user, *pwd, *logname;
 901         char pbuf[MAXHOSTNAMELEN + MAXLOGNAME + 1];
 902         int e, len;
 903
 904         /* XXX FTP_AUTH, and maybe .netrc */
 905
 906         /* send user name and password */
 907         if (url->user[0] == '\0')
 908                 _fetch_netrc_auth(url);
 909         user = url->user;
 910         if (*user == '\0')
 911                 user = getenv("FTP_LOGIN");
 912         if (user == NULL || *user == '\0')
 913                 user = FTP_ANONYMOUS_USER;
 914         if (purl && url->port == _fetch_default_port(url->scheme))
 915                 e = _ftp_cmd(conn, "USER %s@%s", user, url->host);
 916         else if (purl)
 917                 e = _ftp_cmd(conn, "USER %s@%s@%d", user, url->host, url->port);
 918         else
 919                 e = _ftp_cmd(conn, "USER %s", user);
 920
 921         /* did the server request a password? */
 922         if (e == FTP_NEED_PASSWORD) {
 923                 pwd = url->pwd;
 924                 if (*pwd == '\0')
 925                         pwd = getenv("FTP_PASSWORD");
 926                 if (pwd == NULL || *pwd == '\0') {
 927                         if ((logname = getlogin()) == 0)
 928                                 logname = FTP_ANONYMOUS_USER;
 929                         if ((len = snprintf(pbuf, MAXLOGNAME + 1, "%s@", logname)) < 0)
 930                                 len = 0;
 931                         else if (len > MAXLOGNAME)
 932                                 len = MAXLOGNAME;
 933                         gethostname(pbuf + len, sizeof(pbuf) - len);
 934                         pwd = pbuf;
 935                 }
 936                 e = _ftp_cmd(conn, "PASS %s", pwd);
 937         }
 938
 939         return (e);
 940 }
 941
 942 /*
 943  * Log on to FTP server
 944  */
 945 static conn_t *
 946 _ftp_connect(struct url *url, struct url *purl, const char *flags)
 947 {
 948         conn_t *conn;
 949         int e, direct, verbose;
 950 #ifdef INET6
 951         int af = AF_UNSPEC;
 952 #else
 953         int af = AF_INET;
 954 #endif
 955
 956         direct = CHECK_FLAG('d');
 957         verbose = CHECK_FLAG('v');
 958         if (CHECK_FLAG('4'))
 959                 af = AF_INET;
 960         else if (CHECK_FLAG('6'))
 961                 af = AF_INET6;
 962
 963         if (direct)
 964                 purl = NULL;
 965
 966         /* check for proxy */
 967         if (purl) {
 968                 /* XXX proxy authentication! */
 969                 conn = _fetch_connect(purl->host, purl->port, af, verbose);
 970         } else {
 971                 /* no proxy, go straight to target */
 972                 conn = _fetch_connect(url->host, url->port, af, verbose);
 973                 purl = NULL;
 974         }
 975
 976         /* check connection */
 977         if (conn == NULL)
 978                 /* _fetch_connect() has already set an error code */
 979                 return (NULL);
 980
 981         /* expect welcome message */
 982         if ((e = _ftp_chkerr(conn)) != FTP_SERVICE_READY)
 983                 goto fouch;
 984
 985         /* authenticate */
 986         if ((e = _ftp_authenticate(conn, url, purl)) != FTP_LOGGED_IN)
 987                 goto fouch;
 988
 989         /* TODO: Request extended features supported, if any (RFC 3659). */
 990
 991         /* done */
 992         return (conn);
 993
 994 fouch:
 995         if (e != -1)
 996                 _ftp_seterr(e);
 997         _fetch_close(conn);
 998         return (NULL);
 999 }
1000
1001 /*
1002  * Disconnect from server
1003  */
1004 static void
1005 _ftp_disconnect(conn_t *conn)
1006 {
1007         (void)_ftp_cmd(conn, "QUIT");
1008         if (conn == cached_connection && conn->ref == 1)
1009                 cached_connection = NULL;
1010         _fetch_close(conn);
1011 }
1012
1013 /*
1014  * Check if we're already connected
1015  */
1016 static int
1017 _ftp_isconnected(struct url *url)
1018 {
1019         return (cached_connection
1020             && (strcmp(url->host, cached_host.host) == 0)
1021             && (strcmp(url->user, cached_host.user) == 0)
1022             && (strcmp(url->pwd, cached_host.pwd) == 0)
1023             && (url->port == cached_host.port));
1024 }
1025
1026 /*
1027  * Check the cache, reconnect if no luck
1028  */
1029 static conn_t *
1030 _ftp_cached_connect(struct url *url, struct url *purl, const char *flags)
1031 {
1032         conn_t *conn;
1033         int e;
1034
1035         /* set default port */
1036         if (!url->port)
1037                 url->port = _fetch_default_port(url->scheme);
1038
1039         /* try to use previously cached connection */
1040         if (_ftp_isconnected(url)) {
1041                 e = _ftp_cmd(cached_connection, "NOOP");
1042                 if (e == FTP_OK || e == FTP_SYNTAX_ERROR)
1043                         return (_fetch_ref(cached_connection));
1044         }
1045
1046         /* connect to server */
1047         if ((conn = _ftp_connect(url, purl, flags)) == NULL)
1048                 return (NULL);
1049         if (cached_connection)
1050                 _ftp_disconnect(cached_connection);
1051         cached_connection = _fetch_ref(conn);
1052         memcpy(&cached_host, url, sizeof(*url));
1053         return (conn);
1054 }
1055
1056 /*
1057  * Check the proxy settings
1058  */
1059 static struct url *
1060 _ftp_get_proxy(const char *flags)
1061 {
1062         struct url *purl;
1063         char *p;
1064
1065         if (flags != NULL && strchr(flags, 'd') != NULL)
1066                 return (NULL);
1067         if (((p = getenv("FTP_PROXY")) || (p = getenv("ftp_proxy")) ||
1068                 (p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
1069             *p && (purl = fetchParseURL(p)) != NULL) {
1070                 if (!*purl->scheme) {
1071                         if (getenv("FTP_PROXY") || getenv("ftp_proxy"))
1072                                 strcpy(purl->scheme, SCHEME_FTP);
1073                         else
1074                                 strcpy(purl->scheme, SCHEME_HTTP);
1075                 }
1076                 if (!purl->port)
1077                         purl->port = _fetch_default_proxy_port(purl->scheme);
1078                 if (strcasecmp(purl->scheme, SCHEME_FTP) == 0 ||
1079                     strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
1080                         return (purl);
1081                 fetchFreeURL(purl);
1082         }
1083         return (NULL);
1084 }
1085
1086 /*
1087  * Process an FTP request
1088  */
1089 FILE *
1090 _ftp_request(struct url *url, const char *op, struct url_stat *us,
1091     struct url *purl, const char *flags)
1092 {
1093         conn_t *conn;
1094         int oflag;
1095
1096         /* check if we should use HTTP instead */
1097         if (purl && strcasecmp(purl->scheme, SCHEME_HTTP) == 0) {
1098                 if (strcmp(op, "STAT") == 0)
1099                         return (_http_request(url, "HEAD", us, purl, flags));
1100                 else if (strcmp(op, "RETR") == 0)
1101                         return (_http_request(url, "GET", us, purl, flags));
1102                 /*
1103                  * Our HTTP code doesn't support PUT requests yet, so try
1104                  * a direct connection.
1105                  */
1106         }
1107
1108         /* connect to server */
1109         conn = _ftp_cached_connect(url, purl, flags);
1110         if (purl)
1111                 fetchFreeURL(purl);
1112         if (conn == NULL)
1113                 return (NULL);
1114
1115         /* change directory */
1116         if (_ftp_cwd(conn, url->doc) == -1)
1117                 return (NULL);
1118
1119         /* stat file */
1120         if (us && _ftp_stat(conn, url->doc, us) == -1
1121             && fetchLastErrCode != FETCH_PROTO
1122             && fetchLastErrCode != FETCH_UNAVAIL)
1123                 return (NULL);
1124
1125         /* just a stat */
1126         if (strcmp(op, "STAT") == 0)
1127                 return (FILE *)1; /* bogus return value */
1128         if (strcmp(op, "STOR") == 0 || strcmp(op, "APPE") == 0)
1129                 oflag = O_WRONLY;
1130         else
1131                 oflag = O_RDONLY;
1132
1133         /* initiate the transfer */
1134         return (_ftp_transfer(conn, op, url->doc, oflag, url->offset, flags));
1135 }
1136
1137 /*
1138  * Get and stat file
1139  */
1140 FILE *
1141 fetchXGetFTP(struct url *url, struct url_stat *us, const char *flags)
1142 {
1143         return (_ftp_request(url, "RETR", us, _ftp_get_proxy(flags), flags));
1144 }
1145
1146 /*
1147  * Get file
1148  */
1149 FILE *
1150 fetchGetFTP(struct url *url, const char *flags)
1151 {
1152         return (fetchXGetFTP(url, NULL, flags));
1153 }
1154
1155 /*
1156  * Put file
1157  */
1158 FILE *
1159 fetchPutFTP(struct url *url, const char *flags)
1160 {
1161
1162         return (_ftp_request(url, CHECK_FLAG('a') ? "APPE" : "STOR", NULL,
1163             _ftp_get_proxy(flags), flags));
1164 }
1165
1166 /*
1167  * Get file stats
1168  */
1169 int
1170 fetchStatFTP(struct url *url, struct url_stat *us, const char *flags)
1171 {
1172         FILE *f;
1173
1174         f = _ftp_request(url, "STAT", us, _ftp_get_proxy(flags), flags);
1175         if (f == NULL)
1176                 return (-1);
1177         return (0);
1178 }
1179
1180 /*
1181  * List a directory
1182  */
1183 struct url_ent *
1184 fetchListFTP(struct url *url __unused, const char *flags __unused)
1185 {
1186         warnx("fetchListFTP(): not implemented");
1187         return (NULL);
1188 }