lib/libfetch/ftp.c

   1 /*-
   2  * SPDX-License-Identifier: (BSD-3-Clause AND Beerware)
   3  *
   4  * Copyright (c) 1998-2011 Dag-Erling Smørgrav
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer
  12  *    in this position and unchanged.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. The name of the author may not be used to endorse or promote products
  17  *    derived from this software without specific prior written permission
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  *
  30  * $FreeBSD: head/lib/libfetch/ftp.c 341013 2018-11-27 10:45:14Z des $
  31  */
  32
  33 /*
  34  * Portions of this code were taken from or based on ftpio.c:
  35  *
  36  * ----------------------------------------------------------------------------
  37  * "THE BEER-WARE LICENSE" (Revision 42):
  38  * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
  39  * can do whatever you want with this stuff. If we meet some day, and you think
  40  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
  41  * ----------------------------------------------------------------------------
  42  *
  43  * Major Changelog:
  44  *
  45  * Dag-Erling Smørgrav
  46  * 9 Jun 1998
  47  *
  48  * Incorporated into libfetch
  49  *
  50  * Jordan K. Hubbard
  51  * 17 Jan 1996
  52  *
  53  * Turned inside out. Now returns xfers as new file ids, not as a special
  54  * `state' of FTP_t
  55  *
  56  * $ftpioId: ftpio.c,v 1.30 1998/04/11 07:28:53 phk Exp $
  57  *
  58  */
  59
  60 #include <sys/param.h>
  61 #include <sys/socket.h>
  62 #include <netinet/in.h>
  63
  64 #include <ctype.h>
  65 #include <err.h>
  66 #include <errno.h>
  67 #include <fcntl.h>
  68 #include <netdb.h>
  69 #include <stdarg.h>
  70 #include <stdint.h>
  71 #include <stdio.h>
  72 #include <stdlib.h>
  73 #include <string.h>
  74 #include <time.h>
  75 #include <unistd.h>
  76
  77 #include "fetch.h"
  78 #include "common.h"
  79 #include "ftperr.h"
  80
  81 #define FTP_ANONYMOUS_USER      "anonymous"
  82
  83 #define FTP_CONNECTION_ALREADY_OPEN     125
  84 #define FTP_OPEN_DATA_CONNECTION        150
  85 #define FTP_OK                          200
  86 #define FTP_FILE_STATUS                 213
  87 #define FTP_SERVICE_READY               220
  88 #define FTP_TRANSFER_COMPLETE           226
  89 #define FTP_PASSIVE_MODE                227
  90 #define FTP_LPASSIVE_MODE               228
  91 #define FTP_EPASSIVE_MODE               229
  92 #define FTP_LOGGED_IN                   230
  93 #define FTP_FILE_ACTION_OK              250
  94 #define FTP_DIRECTORY_CREATED           257 /* multiple meanings */
  95 #define FTP_FILE_CREATED                257 /* multiple meanings */
  96 #define FTP_WORKING_DIRECTORY           257 /* multiple meanings */
  97 #define FTP_NEED_PASSWORD               331
  98 #define FTP_NEED_ACCOUNT                332
  99 #define FTP_FILE_OK                     350
 100 #define FTP_SYNTAX_ERROR                500
 101 #define FTP_PROTOCOL_ERROR              999
 102
 103 static int ftp_cmd(conn_t *, const char *, ...) __printflike(2, 3);
 104 static struct url cached_host;
 105 static conn_t   *cached_connection;
 106
 107 #define isftpreply(foo)                         \
 108         (isdigit((unsigned char)foo[0]) &&      \
 109             isdigit((unsigned char)foo[1]) &&   \
 110             isdigit((unsigned char)foo[2]) &&   \
 111             (foo[3] == ' ' || foo[3] == '\0'))
 112 #define isftpinfo(foo) \
 113         (isdigit((unsigned char)foo[0]) &&      \
 114             isdigit((unsigned char)foo[1]) &&   \
 115             isdigit((unsigned char)foo[2]) &&   \
 116             foo[3] == '-')
 117
 118 /*
 119  * Translate IPv4 mapped IPv6 address to IPv4 address
 120  */
 121 static void
 122 unmappedaddr(struct sockaddr_in6 *sin6)
 123 {
 124         struct sockaddr_in *sin4;
 125         void *addr;
 126         int port;
 127
 128         if (sin6->sin6_family != AF_INET6 ||
 129             !IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
 130                 return;
 131         sin4 = (struct sockaddr_in *)sin6;
 132         addr = &sin6->sin6_addr.s6_addr[12];
 133         port = sin6->sin6_port;
 134         memset(sin4, 0, sizeof(struct sockaddr_in));
 135         sin4->sin_addr.s_addr = *(uint32_t *)addr;
 136         sin4->sin_port = port;
 137         sin4->sin_family = AF_INET;
 138         sin4->sin_len = sizeof(struct sockaddr_in);
 139 }
 140
 141 /*
 142  * Get server response
 143  */
 144 static int
 145 ftp_chkerr(conn_t *conn)
 146 {
 147         if (fetch_getln(conn) == -1) {
 148                 fetch_syserr();
 149                 return (-1);
 150         }
 151         if (isftpinfo(conn->buf)) {
 152                 while (conn->buflen && !isftpreply(conn->buf)) {
 153                         if (fetch_getln(conn) == -1) {
 154                                 fetch_syserr();
 155                                 return (-1);
 156                         }
 157                 }
 158         }
 159
 160         while (conn->buflen &&
 161             isspace((unsigned char)conn->buf[conn->buflen - 1]))
 162                 conn->buflen--;
 163         conn->buf[conn->buflen] = '\0';
 164
 165         if (!isftpreply(conn->buf)) {
 166                 ftp_seterr(FTP_PROTOCOL_ERROR);
 167                 return (-1);
 168         }
 169
 170         conn->err = (conn->buf[0] - '0') * 100
 171             + (conn->buf[1] - '0') * 10
 172             + (conn->buf[2] - '0');
 173
 174         return (conn->err);
 175 }
 176
 177 /*
 178  * Send a command and check reply
 179  */
 180 static int
 181 ftp_cmd(conn_t *conn, const char *fmt, ...)
 182 {
 183         va_list ap;
 184         size_t len;
 185         char *msg;
 186         int r;
 187
 188         va_start(ap, fmt);
 189         len = vasprintf(&msg, fmt, ap);
 190         va_end(ap);
 191
 192         if (msg == NULL) {
 193                 errno = ENOMEM;
 194                 fetch_syserr();
 195                 return (-1);
 196         }
 197
 198         r = fetch_putln(conn, msg, len);
 199         free(msg);
 200
 201         if (r == -1) {
 202                 fetch_syserr();
 203                 return (-1);
 204         }
 205
 206         return (ftp_chkerr(conn));
 207 }
 208
 209 /*
 210  * Return a pointer to the filename part of a path
 211  */
 212 static const char *
 213 ftp_filename(const char *file, int *len, int *type)
 214 {
 215         const char *s;
 216
 217         if ((s = strrchr(file, '/')) == NULL)
 218                 s = file;
 219         else
 220                 s = s + 1;
 221         *len = strlen(s);
 222         if (*len > 7 && strncmp(s + *len - 7, ";type=", 6) == 0) {
 223                 *type = s[*len - 1];
 224                 *len -= 7;
 225         } else {
 226                 *type = '\0';
 227         }
 228         return (s);
 229 }
 230
 231 /*
 232  * Get current working directory from the reply to a CWD, PWD or CDUP
 233  * command.
 234  */
 235 static int
 236 ftp_pwd(conn_t *conn, char *pwd, size_t pwdlen)
 237 {
 238         char *src, *dst, *end;
 239         int q;
 240
 241         if (conn->err != FTP_WORKING_DIRECTORY &&
 242             conn->err != FTP_FILE_ACTION_OK)
 243                 return (FTP_PROTOCOL_ERROR);
 244         end = conn->buf + conn->buflen;
 245         src = conn->buf + 4;
 246         if (src >= end || *src++ != '"')
 247                 return (FTP_PROTOCOL_ERROR);
 248         for (q = 0, dst = pwd; src < end && pwdlen--; ++src) {
 249                 if (!q && *src == '"')
 250                         q = 1;
 251                 else if (q && *src != '"')
 252                         break;
 253                 else if (q)
 254                         *dst++ = '"', q = 0;
 255                 else
 256                         *dst++ = *src;
 257         }
 258         if (!pwdlen)
 259                 return (FTP_PROTOCOL_ERROR);
 260         *dst = '\0';
 261 #if 0
 262         DEBUGF("pwd: [%s]\n", pwd);
 263 #endif
 264         return (FTP_OK);
 265 }
 266
 267 /*
 268  * Change working directory to the directory that contains the specified
 269  * file.
 270  */
 271 static int
 272 ftp_cwd(conn_t *conn, const char *file)
 273 {
 274         const char *beg, *end;
 275         char pwd[PATH_MAX];
 276         int e, i, len;
 277
 278         /* If no slashes in name, no need to change dirs. */
 279         if ((end = strrchr(file, '/')) == NULL)
 280                 return (0);
 281         if ((e = ftp_cmd(conn, "PWD")) != FTP_WORKING_DIRECTORY ||
 282             (e = ftp_pwd(conn, pwd, sizeof(pwd))) != FTP_OK) {
 283                 ftp_seterr(e);
 284                 return (-1);
 285         }
 286         for (;;) {
 287                 len = strlen(pwd);
 288
 289                 /* Look for a common prefix between PWD and dir to fetch. */
 290                 for (i = 0; i <= len && i <= end - file; ++i)
 291                         if (pwd[i] != file[i])
 292                                 break;
 293 #if 0
 294                 DEBUGF("have: [%.*s|%s]\n", i, pwd, pwd + i);
 295                 DEBUGF("want: [%.*s|%s]\n", i, file, file + i);
 296 #endif
 297                 /* Keep going up a dir until we have a matching prefix. */
 298                 if (pwd[i] == '\0' && (file[i - 1] == '/' || file[i] == '/'))
 299                         break;
 300                 if ((e = ftp_cmd(conn, "CDUP")) != FTP_FILE_ACTION_OK ||
 301                     (e = ftp_cmd(conn, "PWD")) != FTP_WORKING_DIRECTORY ||
 302                     (e = ftp_pwd(conn, pwd, sizeof(pwd))) != FTP_OK) {
 303                         ftp_seterr(e);
 304                         return (-1);
 305                 }
 306         }
 307
 308 #ifdef FTP_COMBINE_CWDS
 309         /* Skip leading slashes, even "////". */
 310         for (beg = file + i; beg < end && *beg == '/'; ++beg, ++i)
 311                 /* nothing */ ;
 312
 313         /* If there is no trailing dir, we're already there. */
 314         if (beg >= end)
 315                 return (0);
 316
 317         /* Change to the directory all in one chunk (e.g., foo/bar/baz). */
 318         e = ftp_cmd(conn, "CWD %.*s", (int)(end - beg), beg);
 319         if (e == FTP_FILE_ACTION_OK)
 320                 return (0);
 321 #endif /* FTP_COMBINE_CWDS */
 322
 323         /* That didn't work so go back to legacy behavior (multiple CWDs). */
 324         for (beg = file + i; beg < end; beg = file + i + 1) {
 325                 while (*beg == '/')
 326                         ++beg, ++i;
 327                 for (++i; file + i < end && file[i] != '/'; ++i)
 328                         /* nothing */ ;
 329                 e = ftp_cmd(conn, "CWD %.*s", (int)(file + i - beg), beg);
 330                 if (e != FTP_FILE_ACTION_OK) {
 331                         ftp_seterr(e);
 332                         return (-1);
 333                 }
 334         }
 335         return (0);
 336 }
 337
 338 /*
 339  * Set transfer mode and data type
 340  */
 341 static int
 342 ftp_mode_type(conn_t *conn, int mode, int type)
 343 {
 344         int e;
 345
 346         switch (mode) {
 347         case 0:
 348         case 's':
 349                 mode = 'S';
 350         case 'S':
 351                 break;
 352         default:
 353                 return (FTP_PROTOCOL_ERROR);
 354         }
 355         if ((e = ftp_cmd(conn, "MODE %c", mode)) != FTP_OK) {
 356                 if (mode == 'S') {
 357                         /*
 358                          * Stream mode is supposed to be the default - so
 359                          * much so that some servers not only do not
 360                          * support any other mode, but do not support the
 361                          * MODE command at all.
 362                          *
 363                          * If "MODE S" fails, it is unlikely that we
 364                          * previously succeeded in setting a different
 365                          * mode.  Therefore, we simply hope that the
 366                          * server is already in the correct mode, and
 367                          * silently ignore the failure.
 368                          */
 369                 } else {
 370                         return (e);
 371                 }
 372         }
 373
 374         switch (type) {
 375         case 0:
 376         case 'i':
 377                 type = 'I';
 378         case 'I':
 379                 break;
 380         case 'a':
 381                 type = 'A';
 382         case 'A':
 383                 break;
 384         case 'd':
 385                 type = 'D';
 386                 /* FALLTHROUGH */
 387         case 'D':
 388                 /* can't handle yet */
 389         default:
 390                 return (FTP_PROTOCOL_ERROR);
 391         }
 392         if ((e = ftp_cmd(conn, "TYPE %c", type)) != FTP_OK)
 393                 return (e);
 394
 395         return (FTP_OK);
 396 }
 397
 398 /*
 399  * Request and parse file stats
 400  */
 401 static int
 402 ftp_stat(conn_t *conn, const char *file, struct url_stat *us)
 403 {
 404         char *ln;
 405         const char *filename;
 406         int filenamelen, type;
 407         struct tm tm;
 408         time_t t;
 409         int e;
 410
 411         us->size = -1;
 412         us->atime = us->mtime = 0;
 413
 414         filename = ftp_filename(file, &filenamelen, &type);
 415
 416         if ((e = ftp_mode_type(conn, 0, type)) != FTP_OK) {
 417                 ftp_seterr(e);
 418                 return (-1);
 419         }
 420
 421         e = ftp_cmd(conn, "SIZE %.*s", filenamelen, filename);
 422         if (e != FTP_FILE_STATUS) {
 423                 ftp_seterr(e);
 424                 return (-1);
 425         }
 426         for (ln = conn->buf + 4; *ln && isspace((unsigned char)*ln); ln++)
 427                 /* nothing */ ;
 428         for (us->size = 0; *ln && isdigit((unsigned char)*ln); ln++)
 429                 us->size = us->size * 10 + *ln - '0';
 430         if (*ln && !isspace((unsigned char)*ln)) {
 431                 ftp_seterr(FTP_PROTOCOL_ERROR);
 432                 us->size = -1;
 433                 return (-1);
 434         }
 435         if (us->size == 0)
 436                 us->size = -1;
 437         DEBUGF("size: [%lld]\n", (long long)us->size);
 438
 439         e = ftp_cmd(conn, "MDTM %.*s", filenamelen, filename);
 440         if (e != FTP_FILE_STATUS) {
 441                 ftp_seterr(e);
 442                 return (-1);
 443         }
 444         for (ln = conn->buf + 4; *ln && isspace((unsigned char)*ln); ln++)
 445                 /* nothing */ ;
 446         switch (strspn(ln, "0123456789")) {
 447         case 14:
 448                 break;
 449         case 15:
 450                 ln++;
 451                 ln[0] = '2';
 452                 ln[1] = '0';
 453                 break;
 454         default:
 455                 ftp_seterr(FTP_PROTOCOL_ERROR);
 456                 return (-1);
 457         }
 458         if (sscanf(ln, "%04d%02d%02d%02d%02d%02d",
 459             &tm.tm_year, &tm.tm_mon, &tm.tm_mday,
 460             &tm.tm_hour, &tm.tm_min, &tm.tm_sec) != 6) {
 461                 ftp_seterr(FTP_PROTOCOL_ERROR);
 462                 return (-1);
 463         }
 464         tm.tm_mon--;
 465         tm.tm_year -= 1900;
 466         tm.tm_isdst = -1;
 467         t = timegm(&tm);
 468         if (t == (time_t)-1)
 469                 t = time(NULL);
 470         us->mtime = t;
 471         us->atime = t;
 472         DEBUGF("last modified: [%04d-%02d-%02d %02d:%02d:%02d]\n",
 473             tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 474             tm.tm_hour, tm.tm_min, tm.tm_sec);
 475         return (0);
 476 }
 477
 478 /*
 479  * I/O functions for FTP
 480  */
 481 struct ftpio {
 482         conn_t  *cconn;         /* Control connection */
 483         conn_t  *dconn;         /* Data connection */
 484         int      dir;           /* Direction */
 485         int      eof;           /* EOF reached */
 486         int      err;           /* Error code */
 487 };
 488
 489 static int       ftp_readfn(void *, char *, int);
 490 static int       ftp_writefn(void *, const char *, int);
 491 static fpos_t    ftp_seekfn(void *, fpos_t, int);
 492 static int       ftp_closefn(void *);
 493
 494 static int
 495 ftp_readfn(void *v, char *buf, int len)
 496 {
 497         struct ftpio *io;
 498         int r;
 499
 500         io = (struct ftpio *)v;
 501         if (io == NULL) {
 502                 errno = EBADF;
 503                 return (-1);
 504         }
 505         if (io->cconn == NULL || io->dconn == NULL || io->dir == O_WRONLY) {
 506                 errno = EBADF;
 507                 return (-1);
 508         }
 509         if (io->err) {
 510                 errno = io->err;
 511                 return (-1);
 512         }
 513         if (io->eof)
 514                 return (0);
 515         r = fetch_read(io->dconn, buf, len);
 516         if (r > 0)
 517                 return (r);
 518         if (r == 0) {
 519                 io->eof = 1;
 520                 return (0);
 521         }
 522         if (errno != EINTR)
 523                 io->err = errno;
 524         return (-1);
 525 }
 526
 527 static int
 528 ftp_writefn(void *v, const char *buf, int len)
 529 {
 530         struct ftpio *io;
 531         int w;
 532
 533         io = (struct ftpio *)v;
 534         if (io == NULL) {
 535                 errno = EBADF;
 536                 return (-1);
 537         }
 538         if (io->cconn == NULL || io->dconn == NULL || io->dir == O_RDONLY) {
 539                 errno = EBADF;
 540                 return (-1);
 541         }
 542         if (io->err) {
 543                 errno = io->err;
 544                 return (-1);
 545         }
 546         w = fetch_write(io->dconn, buf, len);
 547         if (w >= 0)
 548                 return (w);
 549         if (errno != EINTR)
 550                 io->err = errno;
 551         return (-1);
 552 }
 553
 554 static fpos_t
 555 ftp_seekfn(void *v, fpos_t pos __unused, int whence __unused)
 556 {
 557         struct ftpio *io;
 558
 559         io = (struct ftpio *)v;
 560         if (io == NULL) {
 561                 errno = EBADF;
 562                 return (-1);
 563         }
 564         errno = ESPIPE;
 565         return (-1);
 566 }
 567
 568 static int
 569 ftp_closefn(void *v)
 570 {
 571         struct ftpio *io;
 572         int r;
 573
 574         io = (struct ftpio *)v;
 575         if (io == NULL) {
 576                 errno = EBADF;
 577                 return (-1);
 578         }
 579         if (io->dir == -1)
 580                 return (0);
 581         if (io->cconn == NULL || io->dconn == NULL) {
 582                 errno = EBADF;
 583                 return (-1);
 584         }
 585         fetch_close(io->dconn);
 586         io->dir = -1;
 587         io->dconn = NULL;
 588         DEBUGF("Waiting for final status\n");
 589         r = ftp_chkerr(io->cconn);
 590         if (io->cconn == cached_connection && io->cconn->ref == 1)
 591                 cached_connection = NULL;
 592         fetch_close(io->cconn);
 593         free(io);
 594         return (r == FTP_TRANSFER_COMPLETE) ? 0 : -1;
 595 }
 596
 597 static FILE *
 598 ftp_setup(conn_t *cconn, conn_t *dconn, int mode)
 599 {
 600         struct ftpio *io;
 601         FILE *f;
 602
 603         if (cconn == NULL || dconn == NULL)
 604                 return (NULL);
 605         if ((io = malloc(sizeof(*io))) == NULL)
 606                 return (NULL);
 607         io->cconn = cconn;
 608         io->dconn = dconn;
 609         io->dir = mode;
 610         io->eof = io->err = 0;
 611         f = funopen(io, ftp_readfn, ftp_writefn, ftp_seekfn, ftp_closefn);
 612         if (f == NULL)
 613                 free(io);
 614         return (f);
 615 }
 616
 617 /*
 618  * Transfer file
 619  */
 620 static FILE *
 621 ftp_transfer(conn_t *conn, const char *oper, const char *file,
 622     int mode, off_t offset, const char *flags)
 623 {
 624         struct sockaddr_storage sa;
 625         struct sockaddr_in6 *sin6;
 626         struct sockaddr_in *sin4;
 627         const char *bindaddr;
 628         const char *filename;
 629         int filenamelen, type;
 630         int low, pasv, verbose;
 631         int e, sd = -1;
 632         socklen_t l;
 633         char *s;
 634         FILE *df;
 635
 636         /* check flags */
 637         low = CHECK_FLAG('l');
 638         pasv = CHECK_FLAG('p') || !CHECK_FLAG('P');
 639         verbose = CHECK_FLAG('v');
 640
 641         /* passive mode */
 642         if ((s = getenv("FTP_PASSIVE_MODE")) != NULL)
 643                 pasv = (strncasecmp(s, "no", 2) != 0);
 644
 645         /* isolate filename */
 646         filename = ftp_filename(file, &filenamelen, &type);
 647
 648         /* set transfer mode and data type */
 649         if ((e = ftp_mode_type(conn, 0, type)) != FTP_OK)
 650                 goto ouch;
 651
 652         /* find our own address, bind, and listen */
 653         l = sizeof(sa);
 654         if (getsockname(conn->sd, (struct sockaddr *)&sa, &l) == -1)
 655                 goto sysouch;
 656         if (sa.ss_family == AF_INET6)
 657                 unmappedaddr((struct sockaddr_in6 *)&sa);
 658
 659         /* open data socket */
 660         if ((sd = socket(sa.ss_family, SOCK_STREAM, IPPROTO_TCP)) == -1) {
 661                 fetch_syserr();
 662                 return (NULL);
 663         }
 664
 665         if (pasv) {
 666                 u_char addr[64];
 667                 char *ln, *p;
 668                 unsigned int i;
 669                 int port;
 670
 671                 /* send PASV command */
 672                 if (verbose)
 673                         fetch_info("setting passive mode");
 674                 switch (sa.ss_family) {
 675                 case AF_INET:
 676                         if ((e = ftp_cmd(conn, "PASV")) != FTP_PASSIVE_MODE)
 677                                 goto ouch;
 678                         break;
 679                 case AF_INET6:
 680                         if ((e = ftp_cmd(conn, "EPSV")) != FTP_EPASSIVE_MODE) {
 681                                 if (e == -1)
 682                                         goto ouch;
 683                                 if ((e = ftp_cmd(conn, "LPSV")) !=
 684                                     FTP_LPASSIVE_MODE)
 685                                         goto ouch;
 686                         }
 687                         break;
 688                 default:
 689                         e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
 690                         goto ouch;
 691                 }
 692
 693                 /*
 694                  * Find address and port number. The reply to the PASV command
 695                  * is IMHO the one and only weak point in the FTP protocol.
 696                  */
 697                 ln = conn->buf;
 698                 switch (e) {
 699                 case FTP_PASSIVE_MODE:
 700                 case FTP_LPASSIVE_MODE:
 701                         for (p = ln + 3; *p && !isdigit((unsigned char)*p); p++)
 702                                 /* nothing */ ;
 703                         if (!*p) {
 704                                 e = FTP_PROTOCOL_ERROR;
 705                                 goto ouch;
 706                         }
 707                         l = (e == FTP_PASSIVE_MODE ? 6 : 21);
 708                         for (i = 0; *p && i < l; i++, p++)
 709                                 addr[i] = strtol(p, &p, 10);
 710                         if (i < l) {
 711                                 e = FTP_PROTOCOL_ERROR;
 712                                 goto ouch;
 713                         }
 714                         break;
 715                 case FTP_EPASSIVE_MODE:
 716                         for (p = ln + 3; *p && *p != '('; p++)
 717                                 /* nothing */ ;
 718                         if (!*p) {
 719                                 e = FTP_PROTOCOL_ERROR;
 720                                 goto ouch;
 721                         }
 722                         ++p;
 723                         if (sscanf(p, "%c%c%c%d%c", &addr[0], &addr[1], &addr[2],
 724                                 &port, &addr[3]) != 5 ||
 725                             addr[0] != addr[1] ||
 726                             addr[0] != addr[2] || addr[0] != addr[3]) {
 727                                 e = FTP_PROTOCOL_ERROR;
 728                                 goto ouch;
 729                         }
 730                         break;
 731                 }
 732
 733                 /* seek to required offset */
 734                 if (offset)
 735                         if (ftp_cmd(conn, "REST %lu", (u_long)offset) != FTP_FILE_OK)
 736                                 goto sysouch;
 737
 738                 /* construct sockaddr for data socket */
 739                 l = sizeof(sa);
 740                 if (getpeername(conn->sd, (struct sockaddr *)&sa, &l) == -1)
 741                         goto sysouch;
 742                 if (sa.ss_family == AF_INET6)
 743                         unmappedaddr((struct sockaddr_in6 *)&sa);
 744                 switch (sa.ss_family) {
 745                 case AF_INET6:
 746                         sin6 = (struct sockaddr_in6 *)&sa;
 747                         if (e == FTP_EPASSIVE_MODE)
 748                                 sin6->sin6_port = htons(port);
 749                         else {
 750                                 memcpy(&sin6->sin6_addr, addr + 2, 16);
 751                                 memcpy(&sin6->sin6_port, addr + 19, 2);
 752                         }
 753                         break;
 754                 case AF_INET:
 755                         sin4 = (struct sockaddr_in *)&sa;
 756                         if (e == FTP_EPASSIVE_MODE)
 757                                 sin4->sin_port = htons(port);
 758                         else {
 759                                 memcpy(&sin4->sin_addr, addr, 4);
 760                                 memcpy(&sin4->sin_port, addr + 4, 2);
 761                         }
 762                         break;
 763                 default:
 764                         e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
 765                         break;
 766                 }
 767
 768                 /* connect to data port */
 769                 if (verbose)
 770                         fetch_info("opening data connection");
 771                 bindaddr = getenv("FETCH_BIND_ADDRESS");
 772                 if (bindaddr != NULL && *bindaddr != '\0' &&
 773                     (e = fetch_bind(sd, sa.ss_family, bindaddr)) != 0)
 774                         goto ouch;
 775                 if (connect(sd, (struct sockaddr *)&sa, sa.ss_len) == -1)
 776                         goto sysouch;
 777
 778                 /* make the server initiate the transfer */
 779                 if (verbose)
 780                         fetch_info("initiating transfer");
 781                 e = ftp_cmd(conn, "%s %.*s", oper, filenamelen, filename);
 782                 if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
 783                         goto ouch;
 784
 785         } else {
 786                 u_int32_t a;
 787                 u_short p;
 788                 int arg, d;
 789                 char *ap;
 790                 char hname[INET6_ADDRSTRLEN];
 791
 792                 switch (sa.ss_family) {
 793                 case AF_INET6:
 794                         ((struct sockaddr_in6 *)&sa)->sin6_port = 0;
 795 #ifdef IPV6_PORTRANGE
 796                         arg = low ? IPV6_PORTRANGE_DEFAULT : IPV6_PORTRANGE_HIGH;
 797                         if (setsockopt(sd, IPPROTO_IPV6, IPV6_PORTRANGE,
 798                                 (char *)&arg, sizeof(arg)) == -1)
 799                                 goto sysouch;
 800 #endif
 801                         break;
 802                 case AF_INET:
 803                         ((struct sockaddr_in *)&sa)->sin_port = 0;
 804                         arg = low ? IP_PORTRANGE_DEFAULT : IP_PORTRANGE_HIGH;
 805                         if (setsockopt(sd, IPPROTO_IP, IP_PORTRANGE,
 806                                 (char *)&arg, sizeof(arg)) == -1)
 807                                 goto sysouch;
 808                         break;
 809                 }
 810                 if (verbose)
 811                         fetch_info("binding data socket");
 812                 if (bind(sd, (struct sockaddr *)&sa, sa.ss_len) == -1)
 813                         goto sysouch;
 814                 if (listen(sd, 1) == -1)
 815                         goto sysouch;
 816
 817                 /* find what port we're on and tell the server */
 818                 if (getsockname(sd, (struct sockaddr *)&sa, &l) == -1)
 819                         goto sysouch;
 820                 switch (sa.ss_family) {
 821                 case AF_INET:
 822                         sin4 = (struct sockaddr_in *)&sa;
 823                         a = ntohl(sin4->sin_addr.s_addr);
 824                         p = ntohs(sin4->sin_port);
 825                         e = ftp_cmd(conn, "PORT %d,%d,%d,%d,%d,%d",
 826                             (a >> 24) & 0xff, (a >> 16) & 0xff,
 827                             (a >> 8) & 0xff, a & 0xff,
 828                             (p >> 8) & 0xff, p & 0xff);
 829                         break;
 830                 case AF_INET6:
 831 #define UC(b)   (((int)b)&0xff)
 832                         e = -1;
 833                         sin6 = (struct sockaddr_in6 *)&sa;
 834                         sin6->sin6_scope_id = 0;
 835                         if (getnameinfo((struct sockaddr *)&sa, sa.ss_len,
 836                                 hname, sizeof(hname),
 837                                 NULL, 0, NI_NUMERICHOST) == 0) {
 838                                 e = ftp_cmd(conn, "EPRT |%d|%s|%d|", 2, hname,
 839                                     htons(sin6->sin6_port));
 840                                 if (e == -1)
 841                                         goto ouch;
 842                         }
 843                         if (e != FTP_OK) {
 844                                 ap = (char *)&sin6->sin6_addr;
 845                                 e = ftp_cmd(conn,
 846                                     "LPRT %d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d",
 847                                     6, 16,
 848                                     UC(ap[0]), UC(ap[1]), UC(ap[2]), UC(ap[3]),
 849                                     UC(ap[4]), UC(ap[5]), UC(ap[6]), UC(ap[7]),
 850                                     UC(ap[8]), UC(ap[9]), UC(ap[10]), UC(ap[11]),
 851                                     UC(ap[12]), UC(ap[13]), UC(ap[14]), UC(ap[15]),
 852                                     2,
 853                                     (ntohs(sin6->sin6_port) >> 8) & 0xff,
 854                                     ntohs(sin6->sin6_port)        & 0xff);
 855                         }
 856                         break;
 857                 default:
 858                         e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
 859                         goto ouch;
 860                 }
 861                 if (e != FTP_OK)
 862                         goto ouch;
 863
 864                 /* seek to required offset */
 865                 if (offset)
 866                         if (ftp_cmd(conn, "REST %ju", (uintmax_t)offset) != FTP_FILE_OK)
 867                                 goto sysouch;
 868
 869                 /* make the server initiate the transfer */
 870                 if (verbose)
 871                         fetch_info("initiating transfer");
 872                 e = ftp_cmd(conn, "%s %.*s", oper, filenamelen, filename);
 873                 if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
 874                         goto ouch;
 875
 876                 /* accept the incoming connection and go to town */
 877                 if ((d = accept(sd, NULL, NULL)) == -1)
 878                         goto sysouch;
 879                 close(sd);
 880                 sd = d;
 881         }
 882
 883         if ((df = ftp_setup(conn, fetch_reopen(sd), mode)) == NULL)
 884                 goto sysouch;
 885         return (df);
 886
 887 sysouch:
 888         fetch_syserr();
 889         if (sd >= 0)
 890                 close(sd);
 891         return (NULL);
 892
 893 ouch:
 894         if (e != -1)
 895                 ftp_seterr(e);
 896         if (sd >= 0)
 897                 close(sd);
 898         return (NULL);
 899 }
 900
 901 /*
 902  * Authenticate
 903  */
 904 static int
 905 ftp_authenticate(conn_t *conn, struct url *url, struct url *purl)
 906 {
 907         const char *user, *pwd, *logname;
 908         char pbuf[MAXHOSTNAMELEN + MAXLOGNAME + 1];
 909         int e, len;
 910
 911         /* XXX FTP_AUTH, and maybe .netrc */
 912
 913         /* send user name and password */
 914         if (url->user[0] == '\0')
 915                 fetch_netrc_auth(url);
 916         user = url->user;
 917         if (*user == '\0')
 918                 if ((user = getenv("FTP_LOGIN")) != NULL)
 919                         DEBUGF("FTP_LOGIN=%s\n", user);
 920         if (user == NULL || *user == '\0')
 921                 user = FTP_ANONYMOUS_USER;
 922         if (purl && url->port == fetch_default_port(url->scheme))
 923                 e = ftp_cmd(conn, "USER %s@%s", user, url->host);
 924         else if (purl)
 925                 e = ftp_cmd(conn, "USER %s@%s@%d", user, url->host, url->port);
 926         else
 927                 e = ftp_cmd(conn, "USER %s", user);
 928
 929         /* did the server request a password? */
 930         if (e == FTP_NEED_PASSWORD) {
 931                 pwd = url->pwd;
 932                 if (*pwd == '\0')
 933                         if ((pwd = getenv("FTP_PASSWORD")) != NULL)
 934                                 DEBUGF("FTP_PASSWORD=%s\n", pwd);
 935                 if (pwd == NULL || *pwd == '\0') {
 936                         if ((logname = getlogin()) == NULL)
 937                                 logname = FTP_ANONYMOUS_USER;
 938                         if ((len = snprintf(pbuf, MAXLOGNAME + 1, "%s@", logname)) < 0)
 939                                 len = 0;
 940                         else if (len > MAXLOGNAME)
 941                                 len = MAXLOGNAME;
 942                         gethostname(pbuf + len, sizeof(pbuf) - len);
 943                         pwd = pbuf;
 944                 }
 945                 e = ftp_cmd(conn, "PASS %s", pwd);
 946         }
 947
 948         return (e);
 949 }
 950
 951 /*
 952  * Log on to FTP server
 953  */
 954 static conn_t *
 955 ftp_connect(struct url *url, struct url *purl, const char *flags)
 956 {
 957         conn_t *conn;
 958         int e, direct, verbose;
 959 #ifdef INET6
 960         int af = AF_UNSPEC;
 961 #else
 962         int af = AF_INET;
 963 #endif
 964
 965         direct = CHECK_FLAG('d');
 966         verbose = CHECK_FLAG('v');
 967         if (CHECK_FLAG('4'))
 968                 af = AF_INET;
 969         else if (CHECK_FLAG('6'))
 970                 af = AF_INET6;
 971
 972         if (direct)
 973                 purl = NULL;
 974
 975         /* check for proxy */
 976         if (purl) {
 977                 /* XXX proxy authentication! */
 978                 conn = fetch_connect(purl->host, purl->port, af, verbose);
 979         } else {
 980                 /* no proxy, go straight to target */
 981                 conn = fetch_connect(url->host, url->port, af, verbose);
 982                 purl = NULL;
 983         }
 984
 985         /* check connection */
 986         if (conn == NULL)
 987                 /* fetch_connect() has already set an error code */
 988                 return (NULL);
 989
 990         /* expect welcome message */
 991         if ((e = ftp_chkerr(conn)) != FTP_SERVICE_READY)
 992                 goto fouch;
 993
 994         /* authenticate */
 995         if ((e = ftp_authenticate(conn, url, purl)) != FTP_LOGGED_IN)
 996                 goto fouch;
 997
 998         /* TODO: Request extended features supported, if any (RFC 3659). */
 999
1000         /* done */
1001         return (conn);
1002
1003 fouch:
1004         if (e != -1)
1005                 ftp_seterr(e);
1006         fetch_close(conn);
1007         return (NULL);
1008 }
1009
1010 /*
1011  * Disconnect from server
1012  */
1013 static void
1014 ftp_disconnect(conn_t *conn)
1015 {
1016         (void)ftp_cmd(conn, "QUIT");
1017         if (conn == cached_connection && conn->ref == 1)
1018                 cached_connection = NULL;
1019         fetch_close(conn);
1020 }
1021
1022 /*
1023  * Check if we're already connected
1024  */
1025 static int
1026 ftp_isconnected(struct url *url)
1027 {
1028         return (cached_connection
1029             && (strcmp(url->host, cached_host.host) == 0)
1030             && (strcmp(url->user, cached_host.user) == 0)
1031             && (strcmp(url->pwd, cached_host.pwd) == 0)
1032             && (url->port == cached_host.port));
1033 }
1034
1035 /*
1036  * Check the cache, reconnect if no luck
1037  */
1038 static conn_t *
1039 ftp_cached_connect(struct url *url, struct url *purl, const char *flags)
1040 {
1041         conn_t *conn;
1042         int e;
1043
1044         /* set default port */
1045         if (!url->port)
1046                 url->port = fetch_default_port(url->scheme);
1047
1048         /* try to use previously cached connection */
1049         if (ftp_isconnected(url)) {
1050                 e = ftp_cmd(cached_connection, "NOOP");
1051                 if (e == FTP_OK || e == FTP_SYNTAX_ERROR)
1052                         return (fetch_ref(cached_connection));
1053         }
1054
1055         /* connect to server */
1056         if ((conn = ftp_connect(url, purl, flags)) == NULL)
1057                 return (NULL);
1058         if (cached_connection)
1059                 ftp_disconnect(cached_connection);
1060         cached_connection = fetch_ref(conn);
1061         memcpy(&cached_host, url, sizeof(*url));
1062         return (conn);
1063 }
1064
1065 /*
1066  * Check the proxy settings
1067  */
1068 static struct url *
1069 ftp_get_proxy(struct url * url, const char *flags)
1070 {
1071         struct url *purl;
1072         char *p;
1073
1074         if (flags != NULL && strchr(flags, 'd') != NULL)
1075                 return (NULL);
1076         if (fetch_no_proxy_match(url->host))
1077                 return (NULL);
1078         if (((p = getenv("FTP_PROXY")) || (p = getenv("ftp_proxy")) ||
1079                 (p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
1080             *p && (purl = fetchParseURL(p)) != NULL) {
1081                 if (!*purl->scheme) {
1082                         if (getenv("FTP_PROXY") || getenv("ftp_proxy"))
1083                                 strcpy(purl->scheme, SCHEME_FTP);
1084                         else
1085                                 strcpy(purl->scheme, SCHEME_HTTP);
1086                 }
1087                 if (!purl->port)
1088                         purl->port = fetch_default_proxy_port(purl->scheme);
1089                 if (strcmp(purl->scheme, SCHEME_FTP) == 0 ||
1090                     strcmp(purl->scheme, SCHEME_HTTP) == 0)
1091                         return (purl);
1092                 fetchFreeURL(purl);
1093         }
1094         return (NULL);
1095 }
1096
1097 /*
1098  * Process an FTP request
1099  */
1100 FILE *
1101 ftp_request(struct url *url, const char *op, struct url_stat *us,
1102     struct url *purl, const char *flags)
1103 {
1104         conn_t *conn;
1105         int oflag;
1106
1107         /* check if we should use HTTP instead */
1108         if (purl && (strcmp(purl->scheme, SCHEME_HTTP) == 0 ||
1109             strcmp(purl->scheme, SCHEME_HTTPS) == 0)) {
1110                 if (strcmp(op, "STAT") == 0)
1111                         return (http_request(url, "HEAD", us, purl, flags));
1112                 else if (strcmp(op, "RETR") == 0)
1113                         return (http_request(url, "GET", us, purl, flags));
1114                 /*
1115                  * Our HTTP code doesn't support PUT requests yet, so try
1116                  * a direct connection.
1117                  */
1118         }
1119
1120         /* connect to server */
1121         conn = ftp_cached_connect(url, purl, flags);
1122         if (purl)
1123                 fetchFreeURL(purl);
1124         if (conn == NULL)
1125                 return (NULL);
1126
1127         /* change directory */
1128         if (ftp_cwd(conn, url->doc) == -1)
1129                 goto errsock;
1130
1131         /* stat file */
1132         if (us && ftp_stat(conn, url->doc, us) == -1
1133             && fetchLastErrCode != FETCH_PROTO
1134             && fetchLastErrCode != FETCH_UNAVAIL)
1135                 goto errsock;
1136
1137         /* just a stat */
1138         if (strcmp(op, "STAT") == 0) {
1139                 --conn->ref;
1140                 ftp_disconnect(conn);
1141                 return (FILE *)1; /* bogus return value */
1142         }
1143         if (strcmp(op, "STOR") == 0 || strcmp(op, "APPE") == 0)
1144                 oflag = O_WRONLY;
1145         else
1146                 oflag = O_RDONLY;
1147
1148         /* initiate the transfer */
1149         return (ftp_transfer(conn, op, url->doc, oflag, url->offset, flags));
1150
1151 errsock:
1152         ftp_disconnect(conn);
1153         return (NULL);
1154 }
1155
1156 /*
1157  * Get and stat file
1158  */
1159 FILE *
1160 fetchXGetFTP(struct url *url, struct url_stat *us, const char *flags)
1161 {
1162         return (ftp_request(url, "RETR", us, ftp_get_proxy(url, flags), flags));
1163 }
1164
1165 /*
1166  * Get file
1167  */
1168 FILE *
1169 fetchGetFTP(struct url *url, const char *flags)
1170 {
1171         return (fetchXGetFTP(url, NULL, flags));
1172 }
1173
1174 /*
1175  * Put file
1176  */
1177 FILE *
1178 fetchPutFTP(struct url *url, const char *flags)
1179 {
1180         return (ftp_request(url, CHECK_FLAG('a') ? "APPE" : "STOR", NULL,
1181             ftp_get_proxy(url, flags), flags));
1182 }
1183
1184 /*
1185  * Get file stats
1186  */
1187 int
1188 fetchStatFTP(struct url *url, struct url_stat *us, const char *flags)
1189 {
1190         FILE *f;
1191
1192         f = ftp_request(url, "STAT", us, ftp_get_proxy(url, flags), flags);
1193         if (f == NULL)
1194                 return (-1);
1195         /*
1196          * When op is "STAT", ftp_request() will return either NULL or
1197          * (FILE *)1, never a valid FILE *, so we mustn't fclose(f) before
1198          * returning, as it would cause a segfault.
1199          */
1200         return (0);
1201 }
1202
1203 /*
1204  * List a directory
1205  */
1206 struct url_ent *
1207 fetchListFTP(struct url *url __unused, const char *flags __unused)
1208 {
1209         warnx("fetchListFTP(): not implemented");
1210         return (NULL);
1211 }