lib/libfetch/ftp.c

   1 /*-
   2  * Copyright (c) 1998-2011 Dag-Erling Smørgrav
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer
  10  *    in this position and unchanged.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. The name of the author may not be used to endorse or promote products
  15  *    derived from this software without specific prior written permission
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * $FreeBSD: head/lib/libfetch/ftp.c 226537 2011-10-19 11:43:51Z des $
  29  */
  30
  31 /*
  32  * Portions of this code were taken from or based on ftpio.c:
  33  *
  34  * ----------------------------------------------------------------------------
  35  * "THE BEER-WARE LICENSE" (Revision 42):
  36  * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
  37  * can do whatever you want with this stuff. If we meet some day, and you think
  38  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
  39  * ----------------------------------------------------------------------------
  40  *
  41  * Major Changelog:
  42  *
  43  * Dag-Erling Smørgrav
  44  * 9 Jun 1998
  45  *
  46  * Incorporated into libfetch
  47  *
  48  * Jordan K. Hubbard
  49  * 17 Jan 1996
  50  *
  51  * Turned inside out. Now returns xfers as new file ids, not as a special
  52  * `state' of FTP_t
  53  *
  54  * $ftpioId: ftpio.c,v 1.30 1998/04/11 07:28:53 phk Exp $
  55  *
  56  */
  57
  58 #include <sys/param.h>
  59 #include <sys/socket.h>
  60 #include <netinet/in.h>
  61
  62 #include <ctype.h>
  63 #include <err.h>
  64 #include <errno.h>
  65 #include <fcntl.h>
  66 #include <netdb.h>
  67 #include <stdarg.h>
  68 #include <stdint.h>
  69 #include <stdio.h>
  70 #include <stdlib.h>
  71 #include <string.h>
  72 #include <time.h>
  73 #include <unistd.h>
  74
  75 #include "fetch.h"
  76 #include "common.h"
  77 #include "ftperr.h"
  78
  79 #define FTP_ANONYMOUS_USER      "anonymous"
  80
  81 #define FTP_CONNECTION_ALREADY_OPEN     125
  82 #define FTP_OPEN_DATA_CONNECTION        150
  83 #define FTP_OK                          200
  84 #define FTP_FILE_STATUS                 213
  85 #define FTP_SERVICE_READY               220
  86 #define FTP_TRANSFER_COMPLETE           226
  87 #define FTP_PASSIVE_MODE                227
  88 #define FTP_LPASSIVE_MODE               228
  89 #define FTP_EPASSIVE_MODE               229
  90 #define FTP_LOGGED_IN                   230
  91 #define FTP_FILE_ACTION_OK              250
  92 #define FTP_DIRECTORY_CREATED           257 /* multiple meanings */
  93 #define FTP_FILE_CREATED                257 /* multiple meanings */
  94 #define FTP_WORKING_DIRECTORY           257 /* multiple meanings */
  95 #define FTP_NEED_PASSWORD               331
  96 #define FTP_NEED_ACCOUNT                332
  97 #define FTP_FILE_OK                     350
  98 #define FTP_SYNTAX_ERROR                500
  99 #define FTP_PROTOCOL_ERROR              999
 100
 101 static int ftp_cmd(conn_t *, const char *, ...) __printflike(2, 3);
 102 static struct url cached_host;
 103 static conn_t   *cached_connection;
 104
 105 #define isftpreply(foo)                         \
 106         (isdigit((unsigned char)foo[0]) &&      \
 107             isdigit((unsigned char)foo[1]) &&   \
 108             isdigit((unsigned char)foo[2]) &&   \
 109             (foo[3] == ' ' || foo[3] == '\0'))
 110 #define isftpinfo(foo) \
 111         (isdigit((unsigned char)foo[0]) &&      \
 112             isdigit((unsigned char)foo[1]) &&   \
 113             isdigit((unsigned char)foo[2]) &&   \
 114             foo[3] == '-')
 115
 116 /*
 117  * Translate IPv4 mapped IPv6 address to IPv4 address
 118  */
 119 static void
 120 unmappedaddr(struct sockaddr_in6 *sin6)
 121 {
 122         struct sockaddr_in *sin4;
 123         u_int32_t addr;
 124         int port;
 125
 126         if (sin6->sin6_family != AF_INET6 ||
 127             !IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
 128                 return;
 129         sin4 = (struct sockaddr_in *)sin6;
 130         addr = *(u_int32_t *)(uintptr_t)&sin6->sin6_addr.s6_addr[12];
 131         port = sin6->sin6_port;
 132         memset(sin4, 0, sizeof(struct sockaddr_in));
 133         sin4->sin_addr.s_addr = addr;
 134         sin4->sin_port = port;
 135         sin4->sin_family = AF_INET;
 136         sin4->sin_len = sizeof(struct sockaddr_in);
 137 }
 138
 139 /*
 140  * Get server response
 141  */
 142 static int
 143 ftp_chkerr(conn_t *conn)
 144 {
 145         if (fetch_getln(conn) == -1) {
 146                 fetch_syserr();
 147                 return (-1);
 148         }
 149         if (isftpinfo(conn->buf)) {
 150                 while (conn->buflen && !isftpreply(conn->buf)) {
 151                         if (fetch_getln(conn) == -1) {
 152                                 fetch_syserr();
 153                                 return (-1);
 154                         }
 155                 }
 156         }
 157
 158         while (conn->buflen &&
 159             isspace((unsigned char)conn->buf[conn->buflen - 1]))
 160                 conn->buflen--;
 161         conn->buf[conn->buflen] = '\0';
 162
 163         if (!isftpreply(conn->buf)) {
 164                 ftp_seterr(FTP_PROTOCOL_ERROR);
 165                 return (-1);
 166         }
 167
 168         conn->err = (conn->buf[0] - '0') * 100
 169             + (conn->buf[1] - '0') * 10
 170             + (conn->buf[2] - '0');
 171
 172         return (conn->err);
 173 }
 174
 175 /*
 176  * Send a command and check reply
 177  */
 178 static int
 179 ftp_cmd(conn_t *conn, const char *fmt, ...)
 180 {
 181         va_list ap;
 182         size_t len;
 183         char *msg;
 184         int r;
 185
 186         va_start(ap, fmt);
 187         len = vasprintf(&msg, fmt, ap);
 188         va_end(ap);
 189
 190         if (msg == NULL) {
 191                 errno = ENOMEM;
 192                 fetch_syserr();
 193                 return (-1);
 194         }
 195
 196         r = fetch_putln(conn, msg, len);
 197         free(msg);
 198
 199         if (r == -1) {
 200                 fetch_syserr();
 201                 return (-1);
 202         }
 203
 204         return (ftp_chkerr(conn));
 205 }
 206
 207 /*
 208  * Return a pointer to the filename part of a path
 209  */
 210 static const char *
 211 ftp_filename(const char *file, int *len, int *type)
 212 {
 213         const char *s;
 214
 215         if ((s = strrchr(file, '/')) == NULL)
 216                 s = file;
 217         else
 218                 s = s + 1;
 219         *len = strlen(s);
 220         if (*len > 7 && strncmp(s + *len - 7, ";type=", 6) == 0) {
 221                 *type = s[*len - 1];
 222                 *len -= 7;
 223         } else {
 224                 *type = '\0';
 225         }
 226         return (s);
 227 }
 228
 229 /*
 230  * Get current working directory from the reply to a CWD, PWD or CDUP
 231  * command.
 232  */
 233 static int
 234 ftp_pwd(conn_t *conn, char *pwd, size_t pwdlen)
 235 {
 236         char *src, *dst, *end;
 237         int q;
 238
 239         if (conn->err != FTP_WORKING_DIRECTORY &&
 240             conn->err != FTP_FILE_ACTION_OK)
 241                 return (FTP_PROTOCOL_ERROR);
 242         end = conn->buf + conn->buflen;
 243         src = conn->buf + 4;
 244         if (src >= end || *src++ != '"')
 245                 return (FTP_PROTOCOL_ERROR);
 246         for (q = 0, dst = pwd; src < end && pwdlen--; ++src) {
 247                 if (!q && *src == '"')
 248                         q = 1;
 249                 else if (q && *src != '"')
 250                         break;
 251                 else if (q)
 252                         *dst++ = '"', q = 0;
 253                 else
 254                         *dst++ = *src;
 255         }
 256         if (!pwdlen)
 257                 return (FTP_PROTOCOL_ERROR);
 258         *dst = '\0';
 259 #if 0
 260         DEBUG(fprintf(stderr, "pwd: [%s]\n", pwd));
 261 #endif
 262         return (FTP_OK);
 263 }
 264
 265 /*
 266  * Change working directory to the directory that contains the specified
 267  * file.
 268  */
 269 static int
 270 ftp_cwd(conn_t *conn, const char *file)
 271 {
 272         const char *beg, *end;
 273         char pwd[PATH_MAX];
 274         int e, i, len;
 275
 276         /* If no slashes in name, no need to change dirs. */
 277         if ((end = strrchr(file, '/')) == NULL)
 278                 return (0);
 279         if ((e = ftp_cmd(conn, "PWD")) != FTP_WORKING_DIRECTORY ||
 280             (e = ftp_pwd(conn, pwd, sizeof(pwd))) != FTP_OK) {
 281                 ftp_seterr(e);
 282                 return (-1);
 283         }
 284         for (;;) {
 285                 len = strlen(pwd);
 286
 287                 /* Look for a common prefix between PWD and dir to fetch. */
 288                 for (i = 0; i <= len && i <= end - file; ++i)
 289                         if (pwd[i] != file[i])
 290                                 break;
 291 #if 0
 292                 DEBUG(fprintf(stderr, "have: [%.*s|%s]\n", i, pwd, pwd + i));
 293                 DEBUG(fprintf(stderr, "want: [%.*s|%s]\n", i, file, file + i));
 294 #endif
 295                 /* Keep going up a dir until we have a matching prefix. */
 296                 if (pwd[i] == '\0' && (file[i - 1] == '/' || file[i] == '/'))
 297                         break;
 298                 if ((e = ftp_cmd(conn, "CDUP")) != FTP_FILE_ACTION_OK ||
 299                     (e = ftp_cmd(conn, "PWD")) != FTP_WORKING_DIRECTORY ||
 300                     (e = ftp_pwd(conn, pwd, sizeof(pwd))) != FTP_OK) {
 301                         ftp_seterr(e);
 302                         return (-1);
 303                 }
 304         }
 305
 306 #ifdef FTP_COMBINE_CWDS
 307         /* Skip leading slashes, even "////". */
 308         for (beg = file + i; beg < end && *beg == '/'; ++beg, ++i)
 309                 /* nothing */ ;
 310
 311         /* If there is no trailing dir, we're already there. */
 312         if (beg >= end)
 313                 return (0);
 314
 315         /* Change to the directory all in one chunk (e.g., foo/bar/baz). */
 316         e = ftp_cmd(conn, "CWD %.*s", (int)(end - beg), beg);
 317         if (e == FTP_FILE_ACTION_OK)
 318                 return (0);
 319 #endif /* FTP_COMBINE_CWDS */
 320
 321         /* That didn't work so go back to legacy behavior (multiple CWDs). */
 322         for (beg = file + i; beg < end; beg = file + i + 1) {
 323                 while (*beg == '/')
 324                         ++beg, ++i;
 325                 for (++i; file + i < end && file[i] != '/'; ++i)
 326                         /* nothing */ ;
 327                 e = ftp_cmd(conn, "CWD %.*s", (int)(file + i - beg), beg);
 328                 if (e != FTP_FILE_ACTION_OK) {
 329                         ftp_seterr(e);
 330                         return (-1);
 331                 }
 332         }
 333         return (0);
 334 }
 335
 336 /*
 337  * Set transfer mode and data type
 338  */
 339 static int
 340 ftp_mode_type(conn_t *conn, int mode, int type)
 341 {
 342         int e;
 343
 344         switch (mode) {
 345         case 0:
 346         case 's':
 347                 mode = 'S';
 348         case 'S':
 349                 break;
 350         default:
 351                 return (FTP_PROTOCOL_ERROR);
 352         }
 353         if ((e = ftp_cmd(conn, "MODE %c", mode)) != FTP_OK) {
 354                 if (mode == 'S') {
 355                         /*
 356                          * Stream mode is supposed to be the default - so
 357                          * much so that some servers not only do not
 358                          * support any other mode, but do not support the
 359                          * MODE command at all.
 360                          *
 361                          * If "MODE S" fails, it is unlikely that we
 362                          * previously succeeded in setting a different
 363                          * mode.  Therefore, we simply hope that the
 364                          * server is already in the correct mode, and
 365                          * silently ignore the failure.
 366                          */
 367                 } else {
 368                         return (e);
 369                 }
 370         }
 371
 372         switch (type) {
 373         case 0:
 374         case 'i':
 375                 type = 'I';
 376         case 'I':
 377                 break;
 378         case 'a':
 379                 type = 'A';
 380         case 'A':
 381                 break;
 382         case 'd':
 383                 type = 'D';
 384         case 'D':
 385                 /* can't handle yet */
 386         default:
 387                 return (FTP_PROTOCOL_ERROR);
 388         }
 389         if ((e = ftp_cmd(conn, "TYPE %c", type)) != FTP_OK)
 390                 return (e);
 391
 392         return (FTP_OK);
 393 }
 394
 395 /*
 396  * Request and parse file stats
 397  */
 398 static int
 399 ftp_stat(conn_t *conn, const char *file, struct url_stat *us)
 400 {
 401         char *ln;
 402         const char *filename;
 403         int filenamelen, type;
 404         struct tm tm;
 405         time_t t;
 406         int e;
 407
 408         us->size = -1;
 409         us->atime = us->mtime = 0;
 410
 411         filename = ftp_filename(file, &filenamelen, &type);
 412
 413         if ((e = ftp_mode_type(conn, 0, type)) != FTP_OK) {
 414                 ftp_seterr(e);
 415                 return (-1);
 416         }
 417
 418         e = ftp_cmd(conn, "SIZE %.*s", filenamelen, filename);
 419         if (e != FTP_FILE_STATUS) {
 420                 ftp_seterr(e);
 421                 return (-1);
 422         }
 423         for (ln = conn->buf + 4; *ln && isspace((unsigned char)*ln); ln++)
 424                 /* nothing */ ;
 425         for (us->size = 0; *ln && isdigit((unsigned char)*ln); ln++)
 426                 us->size = us->size * 10 + *ln - '0';
 427         if (*ln && !isspace((unsigned char)*ln)) {
 428                 ftp_seterr(FTP_PROTOCOL_ERROR);
 429                 us->size = -1;
 430                 return (-1);
 431         }
 432         if (us->size == 0)
 433                 us->size = -1;
 434         DEBUG(fprintf(stderr, "size: [%lld]\n", (long long)us->size));
 435
 436         e = ftp_cmd(conn, "MDTM %.*s", filenamelen, filename);
 437         if (e != FTP_FILE_STATUS) {
 438                 ftp_seterr(e);
 439                 return (-1);
 440         }
 441         for (ln = conn->buf + 4; *ln && isspace((unsigned char)*ln); ln++)
 442                 /* nothing */ ;
 443         switch (strspn(ln, "0123456789")) {
 444         case 14:
 445                 break;
 446         case 15:
 447                 ln++;
 448                 ln[0] = '2';
 449                 ln[1] = '0';
 450                 break;
 451         default:
 452                 ftp_seterr(FTP_PROTOCOL_ERROR);
 453                 return (-1);
 454         }
 455         if (sscanf(ln, "%04d%02d%02d%02d%02d%02d",
 456             &tm.tm_year, &tm.tm_mon, &tm.tm_mday,
 457             &tm.tm_hour, &tm.tm_min, &tm.tm_sec) != 6) {
 458                 ftp_seterr(FTP_PROTOCOL_ERROR);
 459                 return (-1);
 460         }
 461         tm.tm_mon--;
 462         tm.tm_year -= 1900;
 463         tm.tm_isdst = -1;
 464         t = timegm(&tm);
 465         if (t == (time_t)-1)
 466                 t = time(NULL);
 467         us->mtime = t;
 468         us->atime = t;
 469         DEBUG(fprintf(stderr,
 470             "last modified: [%04d-%02d-%02d %02d:%02d:%02d]\n",
 471             tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 472             tm.tm_hour, tm.tm_min, tm.tm_sec));
 473         return (0);
 474 }
 475
 476 /*
 477  * I/O functions for FTP
 478  */
 479 struct ftpio {
 480         conn_t  *cconn;         /* Control connection */
 481         conn_t  *dconn;         /* Data connection */
 482         int      dir;           /* Direction */
 483         int      eof;           /* EOF reached */
 484         int      err;           /* Error code */
 485 };
 486
 487 static int       ftp_readfn(void *, char *, int);
 488 static int       ftp_writefn(void *, const char *, int);
 489 static fpos_t    ftp_seekfn(void *, fpos_t, int);
 490 static int       ftp_closefn(void *);
 491
 492 static int
 493 ftp_readfn(void *v, char *buf, int len)
 494 {
 495         struct ftpio *io;
 496         int r;
 497
 498         io = (struct ftpio *)v;
 499         if (io == NULL) {
 500                 errno = EBADF;
 501                 return (-1);
 502         }
 503         if (io->cconn == NULL || io->dconn == NULL || io->dir == O_WRONLY) {
 504                 errno = EBADF;
 505                 return (-1);
 506         }
 507         if (io->err) {
 508                 errno = io->err;
 509                 return (-1);
 510         }
 511         if (io->eof)
 512                 return (0);
 513         r = fetch_read(io->dconn, buf, len);
 514         if (r > 0)
 515                 return (r);
 516         if (r == 0) {
 517                 io->eof = 1;
 518                 return (0);
 519         }
 520         if (errno != EINTR)
 521                 io->err = errno;
 522         return (-1);
 523 }
 524
 525 static int
 526 ftp_writefn(void *v, const char *buf, int len)
 527 {
 528         struct ftpio *io;
 529         int w;
 530
 531         io = (struct ftpio *)v;
 532         if (io == NULL) {
 533                 errno = EBADF;
 534                 return (-1);
 535         }
 536         if (io->cconn == NULL || io->dconn == NULL || io->dir == O_RDONLY) {
 537                 errno = EBADF;
 538                 return (-1);
 539         }
 540         if (io->err) {
 541                 errno = io->err;
 542                 return (-1);
 543         }
 544         w = fetch_write(io->dconn, buf, len);
 545         if (w >= 0)
 546                 return (w);
 547         if (errno != EINTR)
 548                 io->err = errno;
 549         return (-1);
 550 }
 551
 552 static fpos_t
 553 ftp_seekfn(void *v, fpos_t pos __unused, int whence __unused)
 554 {
 555         struct ftpio *io;
 556
 557         io = (struct ftpio *)v;
 558         if (io == NULL) {
 559                 errno = EBADF;
 560                 return (-1);
 561         }
 562         errno = ESPIPE;
 563         return (-1);
 564 }
 565
 566 static int
 567 ftp_closefn(void *v)
 568 {
 569         struct ftpio *io;
 570         int r;
 571
 572         io = (struct ftpio *)v;
 573         if (io == NULL) {
 574                 errno = EBADF;
 575                 return (-1);
 576         }
 577         if (io->dir == -1)
 578                 return (0);
 579         if (io->cconn == NULL || io->dconn == NULL) {
 580                 errno = EBADF;
 581                 return (-1);
 582         }
 583         fetch_close(io->dconn);
 584         io->dir = -1;
 585         io->dconn = NULL;
 586         DEBUG(fprintf(stderr, "Waiting for final status\n"));
 587         r = ftp_chkerr(io->cconn);
 588         if (io->cconn == cached_connection && io->cconn->ref == 1)
 589                 cached_connection = NULL;
 590         fetch_close(io->cconn);
 591         free(io);
 592         return (r == FTP_TRANSFER_COMPLETE) ? 0 : -1;
 593 }
 594
 595 static FILE *
 596 ftp_setup(conn_t *cconn, conn_t *dconn, int mode)
 597 {
 598         struct ftpio *io;
 599         FILE *f;
 600
 601         if (cconn == NULL || dconn == NULL)
 602                 return (NULL);
 603         if ((io = malloc(sizeof(*io))) == NULL)
 604                 return (NULL);
 605         io->cconn = cconn;
 606         io->dconn = dconn;
 607         io->dir = mode;
 608         io->eof = io->err = 0;
 609         f = funopen(io, ftp_readfn, ftp_writefn, ftp_seekfn, ftp_closefn);
 610         if (f == NULL)
 611                 free(io);
 612         return (f);
 613 }
 614
 615 /*
 616  * Transfer file
 617  */
 618 static FILE *
 619 ftp_transfer(conn_t *conn, const char *oper, const char *file,
 620     int mode, off_t offset, const char *flags)
 621 {
 622         struct sockaddr_storage sa;
 623         struct sockaddr_in6 *sin6;
 624         struct sockaddr_in *sin4;
 625         const char *bindaddr;
 626         const char *filename;
 627         int filenamelen, type;
 628         int low, pasv, verbose;
 629         int e, sd = -1;
 630         socklen_t l;
 631         char *s;
 632         FILE *df;
 633
 634         /* check flags */
 635         low = CHECK_FLAG('l');
 636         pasv = CHECK_FLAG('p') || !CHECK_FLAG('P');
 637         verbose = CHECK_FLAG('v');
 638
 639         /* passive mode */
 640         if ((s = getenv("FTP_PASSIVE_MODE")) != NULL)
 641                 pasv = (strncasecmp(s, "no", 2) != 0);
 642
 643         /* isolate filename */
 644         filename = ftp_filename(file, &filenamelen, &type);
 645
 646         /* set transfer mode and data type */
 647         if ((e = ftp_mode_type(conn, 0, type)) != FTP_OK)
 648                 goto ouch;
 649
 650         /* find our own address, bind, and listen */
 651         l = sizeof(sa);
 652         if (getsockname(conn->sd, (struct sockaddr *)&sa, &l) == -1)
 653                 goto sysouch;
 654         if (sa.ss_family == AF_INET6)
 655                 unmappedaddr((struct sockaddr_in6 *)&sa);
 656
 657         /* open data socket */
 658         if ((sd = socket(sa.ss_family, SOCK_STREAM, IPPROTO_TCP)) == -1) {
 659                 fetch_syserr();
 660                 return (NULL);
 661         }
 662
 663         if (pasv) {
 664                 u_char addr[64];
 665                 char *ln, *p;
 666                 unsigned int i;
 667                 int port;
 668
 669                 /* send PASV command */
 670                 if (verbose)
 671                         fetch_info("setting passive mode");
 672                 switch (sa.ss_family) {
 673                 case AF_INET:
 674                         if ((e = ftp_cmd(conn, "PASV")) != FTP_PASSIVE_MODE)
 675                                 goto ouch;
 676                         break;
 677                 case AF_INET6:
 678                         if ((e = ftp_cmd(conn, "EPSV")) != FTP_EPASSIVE_MODE) {
 679                                 if (e == -1)
 680                                         goto ouch;
 681                                 if ((e = ftp_cmd(conn, "LPSV")) !=
 682                                     FTP_LPASSIVE_MODE)
 683                                         goto ouch;
 684                         }
 685                         break;
 686                 default:
 687                         e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
 688                         goto ouch;
 689                 }
 690
 691                 /*
 692                  * Find address and port number. The reply to the PASV command
 693                  * is IMHO the one and only weak point in the FTP protocol.
 694                  */
 695                 ln = conn->buf;
 696                 switch (e) {
 697                 case FTP_PASSIVE_MODE:
 698                 case FTP_LPASSIVE_MODE:
 699                         for (p = ln + 3; *p && !isdigit((unsigned char)*p); p++)
 700                                 /* nothing */ ;
 701                         if (!*p) {
 702                                 e = FTP_PROTOCOL_ERROR;
 703                                 goto ouch;
 704                         }
 705                         l = (e == FTP_PASSIVE_MODE ? 6 : 21);
 706                         for (i = 0; *p && i < l; i++, p++)
 707                                 addr[i] = strtol(p, &p, 10);
 708                         if (i < l) {
 709                                 e = FTP_PROTOCOL_ERROR;
 710                                 goto ouch;
 711                         }
 712                         break;
 713                 case FTP_EPASSIVE_MODE:
 714                         for (p = ln + 3; *p && *p != '('; p++)
 715                                 /* nothing */ ;
 716                         if (!*p) {
 717                                 e = FTP_PROTOCOL_ERROR;
 718                                 goto ouch;
 719                         }
 720                         ++p;
 721                         if (sscanf(p, "%c%c%c%d%c", &addr[0], &addr[1], &addr[2],
 722                                 &port, &addr[3]) != 5 ||
 723                             addr[0] != addr[1] ||
 724                             addr[0] != addr[2] || addr[0] != addr[3]) {
 725                                 e = FTP_PROTOCOL_ERROR;
 726                                 goto ouch;
 727                         }
 728                         break;
 729                 }
 730
 731                 /* seek to required offset */
 732                 if (offset)
 733                         if (ftp_cmd(conn, "REST %lu", (u_long)offset) != FTP_FILE_OK)
 734                                 goto sysouch;
 735
 736                 /* construct sockaddr for data socket */
 737                 l = sizeof(sa);
 738                 if (getpeername(conn->sd, (struct sockaddr *)&sa, &l) == -1)
 739                         goto sysouch;
 740                 if (sa.ss_family == AF_INET6)
 741                         unmappedaddr((struct sockaddr_in6 *)&sa);
 742                 switch (sa.ss_family) {
 743                 case AF_INET6:
 744                         sin6 = (struct sockaddr_in6 *)&sa;
 745                         if (e == FTP_EPASSIVE_MODE)
 746                                 sin6->sin6_port = htons(port);
 747                         else {
 748                                 memcpy(&sin6->sin6_addr, addr + 2, 16);
 749                                 memcpy(&sin6->sin6_port, addr + 19, 2);
 750                         }
 751                         break;
 752                 case AF_INET:
 753                         sin4 = (struct sockaddr_in *)&sa;
 754                         if (e == FTP_EPASSIVE_MODE)
 755                                 sin4->sin_port = htons(port);
 756                         else {
 757                                 memcpy(&sin4->sin_addr, addr, 4);
 758                                 memcpy(&sin4->sin_port, addr + 4, 2);
 759                         }
 760                         break;
 761                 default:
 762                         e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
 763                         break;
 764                 }
 765
 766                 /* connect to data port */
 767                 if (verbose)
 768                         fetch_info("opening data connection");
 769                 bindaddr = getenv("FETCH_BIND_ADDRESS");
 770                 if (bindaddr != NULL && *bindaddr != '\0' &&
 771                     fetch_bind(sd, sa.ss_family, bindaddr) != 0)
 772                         goto sysouch;
 773                 if (connect(sd, (struct sockaddr *)&sa, sa.ss_len) == -1)
 774                         goto sysouch;
 775
 776                 /* make the server initiate the transfer */
 777                 if (verbose)
 778                         fetch_info("initiating transfer");
 779                 e = ftp_cmd(conn, "%s %.*s", oper, filenamelen, filename);
 780                 if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
 781                         goto ouch;
 782
 783         } else {
 784                 u_int32_t a;
 785                 u_short p;
 786                 int arg, d;
 787                 char *ap;
 788                 char hname[INET6_ADDRSTRLEN];
 789
 790                 switch (sa.ss_family) {
 791                 case AF_INET6:
 792                         ((struct sockaddr_in6 *)&sa)->sin6_port = 0;
 793 #ifdef IPV6_PORTRANGE
 794                         arg = low ? IPV6_PORTRANGE_DEFAULT : IPV6_PORTRANGE_HIGH;
 795                         if (setsockopt(sd, IPPROTO_IPV6, IPV6_PORTRANGE,
 796                                 (char *)&arg, sizeof(arg)) == -1)
 797                                 goto sysouch;
 798 #endif
 799                         break;
 800                 case AF_INET:
 801                         ((struct sockaddr_in *)&sa)->sin_port = 0;
 802                         arg = low ? IP_PORTRANGE_DEFAULT : IP_PORTRANGE_HIGH;
 803                         if (setsockopt(sd, IPPROTO_IP, IP_PORTRANGE,
 804                                 (char *)&arg, sizeof(arg)) == -1)
 805                                 goto sysouch;
 806                         break;
 807                 }
 808                 if (verbose)
 809                         fetch_info("binding data socket");
 810                 if (bind(sd, (struct sockaddr *)&sa, sa.ss_len) == -1)
 811                         goto sysouch;
 812                 if (listen(sd, 1) == -1)
 813                         goto sysouch;
 814
 815                 /* find what port we're on and tell the server */
 816                 if (getsockname(sd, (struct sockaddr *)&sa, &l) == -1)
 817                         goto sysouch;
 818                 switch (sa.ss_family) {
 819                 case AF_INET:
 820                         sin4 = (struct sockaddr_in *)&sa;
 821                         a = ntohl(sin4->sin_addr.s_addr);
 822                         p = ntohs(sin4->sin_port);
 823                         e = ftp_cmd(conn, "PORT %d,%d,%d,%d,%d,%d",
 824                             (a >> 24) & 0xff, (a >> 16) & 0xff,
 825                             (a >> 8) & 0xff, a & 0xff,
 826                             (p >> 8) & 0xff, p & 0xff);
 827                         break;
 828                 case AF_INET6:
 829 #define UC(b)   (((int)b)&0xff)
 830                         e = -1;
 831                         sin6 = (struct sockaddr_in6 *)&sa;
 832                         sin6->sin6_scope_id = 0;
 833                         if (getnameinfo((struct sockaddr *)&sa, sa.ss_len,
 834                                 hname, sizeof(hname),
 835                                 NULL, 0, NI_NUMERICHOST) == 0) {
 836                                 e = ftp_cmd(conn, "EPRT |%d|%s|%d|", 2, hname,
 837                                     htons(sin6->sin6_port));
 838                                 if (e == -1)
 839                                         goto ouch;
 840                         }
 841                         if (e != FTP_OK) {
 842                                 ap = (char *)&sin6->sin6_addr;
 843                                 e = ftp_cmd(conn,
 844                                     "LPRT %d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d",
 845                                     6, 16,
 846                                     UC(ap[0]), UC(ap[1]), UC(ap[2]), UC(ap[3]),
 847                                     UC(ap[4]), UC(ap[5]), UC(ap[6]), UC(ap[7]),
 848                                     UC(ap[8]), UC(ap[9]), UC(ap[10]), UC(ap[11]),
 849                                     UC(ap[12]), UC(ap[13]), UC(ap[14]), UC(ap[15]),
 850                                     2,
 851                                     (ntohs(sin6->sin6_port) >> 8) & 0xff,
 852                                     ntohs(sin6->sin6_port)        & 0xff);
 853                         }
 854                         break;
 855                 default:
 856                         e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
 857                         goto ouch;
 858                 }
 859                 if (e != FTP_OK)
 860                         goto ouch;
 861
 862                 /* seek to required offset */
 863                 if (offset)
 864                         if (ftp_cmd(conn, "REST %ju", (uintmax_t)offset) != FTP_FILE_OK)
 865                                 goto sysouch;
 866
 867                 /* make the server initiate the transfer */
 868                 if (verbose)
 869                         fetch_info("initiating transfer");
 870                 e = ftp_cmd(conn, "%s %.*s", oper, filenamelen, filename);
 871                 if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
 872                         goto ouch;
 873
 874                 /* accept the incoming connection and go to town */
 875                 if ((d = accept(sd, NULL, NULL)) == -1)
 876                         goto sysouch;
 877                 close(sd);
 878                 sd = d;
 879         }
 880
 881         if ((df = ftp_setup(conn, fetch_reopen(sd), mode)) == NULL)
 882                 goto sysouch;
 883         return (df);
 884
 885 sysouch:
 886         fetch_syserr();
 887         if (sd >= 0)
 888                 close(sd);
 889         return (NULL);
 890
 891 ouch:
 892         if (e != -1)
 893                 ftp_seterr(e);
 894         if (sd >= 0)
 895                 close(sd);
 896         return (NULL);
 897 }
 898
 899 /*
 900  * Authenticate
 901  */
 902 static int
 903 ftp_authenticate(conn_t *conn, struct url *url, struct url *purl)
 904 {
 905         const char *user, *pwd, *logname;
 906         char pbuf[MAXHOSTNAMELEN + MAXLOGNAME + 1];
 907         int e, len;
 908
 909         /* XXX FTP_AUTH, and maybe .netrc */
 910
 911         /* send user name and password */
 912         if (url->user[0] == '\0')
 913                 fetch_netrc_auth(url);
 914         user = url->user;
 915         if (*user == '\0')
 916                 user = getenv("FTP_LOGIN");
 917         if (user == NULL || *user == '\0')
 918                 user = FTP_ANONYMOUS_USER;
 919         if (purl && url->port == fetch_default_port(url->scheme))
 920                 e = ftp_cmd(conn, "USER %s@%s", user, url->host);
 921         else if (purl)
 922                 e = ftp_cmd(conn, "USER %s@%s@%d", user, url->host, url->port);
 923         else
 924                 e = ftp_cmd(conn, "USER %s", user);
 925
 926         /* did the server request a password? */
 927         if (e == FTP_NEED_PASSWORD) {
 928                 pwd = url->pwd;
 929                 if (*pwd == '\0')
 930                         pwd = getenv("FTP_PASSWORD");
 931                 if (pwd == NULL || *pwd == '\0') {
 932                         if ((logname = getlogin()) == NULL)
 933                                 logname = FTP_ANONYMOUS_USER;
 934                         if ((len = snprintf(pbuf, MAXLOGNAME + 1, "%s@", logname)) < 0)
 935                                 len = 0;
 936                         else if (len > MAXLOGNAME)
 937                                 len = MAXLOGNAME;
 938                         gethostname(pbuf + len, sizeof(pbuf) - len);
 939                         pwd = pbuf;
 940                 }
 941                 e = ftp_cmd(conn, "PASS %s", pwd);
 942         }
 943
 944         return (e);
 945 }
 946
 947 /*
 948  * Log on to FTP server
 949  */
 950 static conn_t *
 951 ftp_connect(struct url *url, struct url *purl, const char *flags)
 952 {
 953         conn_t *conn;
 954         int e, direct, verbose;
 955 #ifdef INET6
 956         int af = AF_UNSPEC;
 957 #else
 958         int af = AF_INET;
 959 #endif
 960
 961         direct = CHECK_FLAG('d');
 962         verbose = CHECK_FLAG('v');
 963         if (CHECK_FLAG('4'))
 964                 af = AF_INET;
 965         else if (CHECK_FLAG('6'))
 966                 af = AF_INET6;
 967
 968         if (direct)
 969                 purl = NULL;
 970
 971         /* check for proxy */
 972         if (purl) {
 973                 /* XXX proxy authentication! */
 974                 conn = fetch_connect(purl->host, purl->port, af, verbose);
 975         } else {
 976                 /* no proxy, go straight to target */
 977                 conn = fetch_connect(url->host, url->port, af, verbose);
 978                 purl = NULL;
 979         }
 980
 981         /* check connection */
 982         if (conn == NULL)
 983                 /* fetch_connect() has already set an error code */
 984                 return (NULL);
 985
 986         /* expect welcome message */
 987         if ((e = ftp_chkerr(conn)) != FTP_SERVICE_READY)
 988                 goto fouch;
 989
 990         /* authenticate */
 991         if ((e = ftp_authenticate(conn, url, purl)) != FTP_LOGGED_IN)
 992                 goto fouch;
 993
 994         /* TODO: Request extended features supported, if any (RFC 3659). */
 995
 996         /* done */
 997         return (conn);
 998
 999 fouch:
1000         if (e != -1)
1001                 ftp_seterr(e);
1002         fetch_close(conn);
1003         return (NULL);
1004 }
1005
1006 /*
1007  * Disconnect from server
1008  */
1009 static void
1010 ftp_disconnect(conn_t *conn)
1011 {
1012         (void)ftp_cmd(conn, "QUIT");
1013         if (conn == cached_connection && conn->ref == 1)
1014                 cached_connection = NULL;
1015         fetch_close(conn);
1016 }
1017
1018 /*
1019  * Check if we're already connected
1020  */
1021 static int
1022 ftp_isconnected(struct url *url)
1023 {
1024         return (cached_connection
1025             && (strcmp(url->host, cached_host.host) == 0)
1026             && (strcmp(url->user, cached_host.user) == 0)
1027             && (strcmp(url->pwd, cached_host.pwd) == 0)
1028             && (url->port == cached_host.port));
1029 }
1030
1031 /*
1032  * Check the cache, reconnect if no luck
1033  */
1034 static conn_t *
1035 ftp_cached_connect(struct url *url, struct url *purl, const char *flags)
1036 {
1037         conn_t *conn;
1038         int e;
1039
1040         /* set default port */
1041         if (!url->port)
1042                 url->port = fetch_default_port(url->scheme);
1043
1044         /* try to use previously cached connection */
1045         if (ftp_isconnected(url)) {
1046                 e = ftp_cmd(cached_connection, "NOOP");
1047                 if (e == FTP_OK || e == FTP_SYNTAX_ERROR)
1048                         return (fetch_ref(cached_connection));
1049         }
1050
1051         /* connect to server */
1052         if ((conn = ftp_connect(url, purl, flags)) == NULL)
1053                 return (NULL);
1054         if (cached_connection)
1055                 ftp_disconnect(cached_connection);
1056         cached_connection = fetch_ref(conn);
1057         memcpy(&cached_host, url, sizeof(*url));
1058         return (conn);
1059 }
1060
1061 /*
1062  * Check the proxy settings
1063  */
1064 static struct url *
1065 ftp_get_proxy(struct url * url, const char *flags)
1066 {
1067         struct url *purl;
1068         char *p;
1069
1070         if (flags != NULL && strchr(flags, 'd') != NULL)
1071                 return (NULL);
1072         if (fetch_no_proxy_match(url->host))
1073                 return (NULL);
1074         if (((p = getenv("FTP_PROXY")) || (p = getenv("ftp_proxy")) ||
1075                 (p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
1076             *p && (purl = fetchParseURL(p)) != NULL) {
1077                 if (!*purl->scheme) {
1078                         if (getenv("FTP_PROXY") || getenv("ftp_proxy"))
1079                                 strcpy(purl->scheme, SCHEME_FTP);
1080                         else
1081                                 strcpy(purl->scheme, SCHEME_HTTP);
1082                 }
1083                 if (!purl->port)
1084                         purl->port = fetch_default_proxy_port(purl->scheme);
1085                 if (strcasecmp(purl->scheme, SCHEME_FTP) == 0 ||
1086                     strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
1087                         return (purl);
1088                 fetchFreeURL(purl);
1089         }
1090         return (NULL);
1091 }
1092
1093 /*
1094  * Process an FTP request
1095  */
1096 FILE *
1097 ftp_request(struct url *url, const char *op, struct url_stat *us,
1098     struct url *purl, const char *flags)
1099 {
1100         conn_t *conn;
1101         int oflag;
1102
1103         /* check if we should use HTTP instead */
1104         if (purl && strcasecmp(purl->scheme, SCHEME_HTTP) == 0) {
1105                 if (strcmp(op, "STAT") == 0)
1106                         return (http_request(url, "HEAD", us, purl, flags));
1107                 else if (strcmp(op, "RETR") == 0)
1108                         return (http_request(url, "GET", us, purl, flags));
1109                 /*
1110                  * Our HTTP code doesn't support PUT requests yet, so try
1111                  * a direct connection.
1112                  */
1113         }
1114
1115         /* connect to server */
1116         conn = ftp_cached_connect(url, purl, flags);
1117         if (purl)
1118                 fetchFreeURL(purl);
1119         if (conn == NULL)
1120                 return (NULL);
1121
1122         /* change directory */
1123         if (ftp_cwd(conn, url->doc) == -1)
1124                 goto errsock;
1125
1126         /* stat file */
1127         if (us && ftp_stat(conn, url->doc, us) == -1
1128             && fetchLastErrCode != FETCH_PROTO
1129             && fetchLastErrCode != FETCH_UNAVAIL)
1130                 goto errsock;
1131
1132         /* just a stat */
1133         if (strcmp(op, "STAT") == 0) {
1134                 --conn->ref;
1135                 ftp_disconnect(conn);
1136                 return (FILE *)1; /* bogus return value */
1137         }
1138         if (strcmp(op, "STOR") == 0 || strcmp(op, "APPE") == 0)
1139                 oflag = O_WRONLY;
1140         else
1141                 oflag = O_RDONLY;
1142
1143         /* initiate the transfer */
1144         return (ftp_transfer(conn, op, url->doc, oflag, url->offset, flags));
1145
1146 errsock:
1147         ftp_disconnect(conn);
1148         return (NULL);
1149 }
1150
1151 /*
1152  * Get and stat file
1153  */
1154 FILE *
1155 fetchXGetFTP(struct url *url, struct url_stat *us, const char *flags)
1156 {
1157         return (ftp_request(url, "RETR", us, ftp_get_proxy(url, flags), flags));
1158 }
1159
1160 /*
1161  * Get file
1162  */
1163 FILE *
1164 fetchGetFTP(struct url *url, const char *flags)
1165 {
1166         return (fetchXGetFTP(url, NULL, flags));
1167 }
1168
1169 /*
1170  * Put file
1171  */
1172 FILE *
1173 fetchPutFTP(struct url *url, const char *flags)
1174 {
1175         return (ftp_request(url, CHECK_FLAG('a') ? "APPE" : "STOR", NULL,
1176             ftp_get_proxy(url, flags), flags));
1177 }
1178
1179 /*
1180  * Get file stats
1181  */
1182 int
1183 fetchStatFTP(struct url *url, struct url_stat *us, const char *flags)
1184 {
1185         FILE *f;
1186
1187         f = ftp_request(url, "STAT", us, ftp_get_proxy(url, flags), flags);
1188         if (f == NULL)
1189                 return (-1);
1190         /*
1191          * When op is "STAT", ftp_request() will return either NULL or
1192          * (FILE *)1, never a valid FILE *, so we mustn't fclose(f) before
1193          * returning, as it would cause a segfault.
1194          */
1195         return (0);
1196 }
1197
1198 /*
1199  * List a directory
1200  */
1201 struct url_ent *
1202 fetchListFTP(struct url *url __unused, const char *flags __unused)
1203 {
1204         warnx("fetchListFTP(): not implemented");
1205         return (NULL);
1206 }