xref: /netbsd-src/share/examples/refuse/ian/libfetch/ftp.c (revision deb6f0161a9109e7de9b519dc8dfb9478668dcdd)
1 /*-
2  * Copyright (c) 1998-2004 Dag-Erling Co�dan Sm�rgrav
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer
10  *    in this position and unchanged.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. The name of the author may not be used to endorse or promote products
15  *    derived from this software without specific prior written permission
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include "free2net.h"
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD: src/lib/libfetch/ftp.c,v 1.91.2.2 2007/05/16 07:04:02 njl Exp $");
33 
34 /*
35  * Portions of this code were taken from or based on ftpio.c:
36  *
37  * ----------------------------------------------------------------------------
38  * "THE BEER-WARE LICENSE" (Revision 42):
39  * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
40  * can do whatever you want with this stuff. If we meet some day, and you think
41  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
42  * ----------------------------------------------------------------------------
43  *
44  * Major Changelog:
45  *
46  * Dag-Erling Co�dan Sm�rgrav
47  * 9 Jun 1998
48  *
49  * Incorporated into libfetch
50  *
51  * Jordan K. Hubbard
52  * 17 Jan 1996
53  *
54  * Turned inside out. Now returns xfers as new file ids, not as a special
55  * `state' of FTP_t
56  *
57  * $ftpioId: ftpio.c,v 1.30 1998/04/11 07:28:53 phk Exp $
58  *
59  */
60 
61 #include <sys/param.h>
62 #include <sys/socket.h>
63 #include <netinet/in.h>
64 
65 #include <ctype.h>
66 #include <err.h>
67 #include <errno.h>
68 #include <fcntl.h>
69 #include <netdb.h>
70 #include <stdarg.h>
71 #include <stdint.h>
72 #include <stdio.h>
73 #include <stdlib.h>
74 #include <string.h>
75 #include <time.h>
76 #include <unistd.h>
77 
78 #include "fetch.h"
79 #include "common.h"
80 #include "ftperr.h"
81 
82 #define FTP_ANONYMOUS_USER	"anonymous"
83 
84 #define FTP_CONNECTION_ALREADY_OPEN	125
85 #define FTP_OPEN_DATA_CONNECTION	150
86 #define FTP_OK				200
87 #define FTP_FILE_STATUS			213
88 #define FTP_SERVICE_READY		220
89 #define FTP_TRANSFER_COMPLETE		226
90 #define FTP_PASSIVE_MODE		227
91 #define FTP_LPASSIVE_MODE		228
92 #define FTP_EPASSIVE_MODE		229
93 #define FTP_LOGGED_IN			230
94 #define FTP_FILE_ACTION_OK		250
95 #define FTP_DIRECTORY_CREATED		257 /* multiple meanings */
96 #define FTP_FILE_CREATED		257 /* multiple meanings */
97 #define FTP_WORKING_DIRECTORY		257 /* multiple meanings */
98 #define FTP_NEED_PASSWORD		331
99 #define FTP_NEED_ACCOUNT		332
100 #define FTP_FILE_OK			350
101 #define FTP_SYNTAX_ERROR		500
102 #define FTP_PROTOCOL_ERROR		999
103 
104 static struct url cached_host;
105 static conn_t	*cached_connection;
106 
107 #define isftpreply(foo) (isdigit((unsigned)foo[0]) && \
108 			 isdigit((unsigned)foo[1]) && \
109 			 isdigit((unsigned)foo[2]) && \
110 			 (foo[3] == ' ' || foo[3] == '\0'))
111 #define isftpinfo(foo) (isdigit((unsigned)foo[0]) && \
112 			 isdigit((unsigned)foo[1]) && \
113 			 isdigit((unsigned)foo[2]) && foo[3] == '-')
114 
115 /*
116  * Translate IPv4 mapped IPv6 address to IPv4 address
117  */
118 static void
119 unmappedaddr(struct sockaddr_in6 *sin6)
120 {
121 	struct sockaddr_in *sin4;
122 	u_int32_t addr;
123 	int port;
124 
125 	if (sin6->sin6_family != AF_INET6 ||
126 	    !IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
127 		return;
128 	sin4 = (struct sockaddr_in *)(void *)sin6;
129 	addr = *(u_int32_t *)(void *)&sin6->sin6_addr.s6_addr[12];
130 	port = sin6->sin6_port;
131 	memset(sin4, 0, sizeof(struct sockaddr_in));
132 	sin4->sin_addr.s_addr = addr;
133 	sin4->sin_port = port;
134 	sin4->sin_family = AF_INET;
135 	sin4->sin_len = sizeof(struct sockaddr_in);
136 }
137 
138 /*
139  * Get server response
140  */
141 static int
142 _ftp_chkerr(conn_t *conn)
143 {
144 	if (_fetch_getln(conn) == -1) {
145 		_fetch_syserr();
146 		return (-1);
147 	}
148 	if (isftpinfo(conn->buf)) {
149 		while (conn->buflen && !isftpreply(conn->buf)) {
150 			if (_fetch_getln(conn) == -1) {
151 				_fetch_syserr();
152 				return (-1);
153 			}
154 		}
155 	}
156 
157 	while (conn->buflen && isspace((unsigned)conn->buf[conn->buflen - 1]))
158 		conn->buflen--;
159 	conn->buf[conn->buflen] = '\0';
160 
161 	if (!isftpreply(conn->buf)) {
162 		_ftp_seterr(FTP_PROTOCOL_ERROR);
163 		return (-1);
164 	}
165 
166 	conn->err = (conn->buf[0] - '0') * 100
167 	    + (conn->buf[1] - '0') * 10
168 	    + (conn->buf[2] - '0');
169 
170 	return (conn->err);
171 }
172 
173 /*
174  * Send a command and check reply
175  */
176 static int
177 _ftp_cmd(conn_t *conn, const char *fmt, ...)
178 {
179 	va_list ap;
180 	size_t len;
181 	char *msg;
182 	int r;
183 
184 	va_start(ap, fmt);
185 	len = vasprintf(&msg, fmt, ap);
186 	va_end(ap);
187 
188 	if (msg == NULL) {
189 		errno = ENOMEM;
190 		_fetch_syserr();
191 		return (-1);
192 	}
193 
194 	r = _fetch_putln(conn, msg, len);
195 	free(msg);
196 
197 	if (r == -1) {
198 		_fetch_syserr();
199 		return (-1);
200 	}
201 
202 	return (_ftp_chkerr(conn));
203 }
204 
205 /*
206  * Return a pointer to the filename part of a path
207  */
208 static const char *
209 _ftp_filename(const char *file, int *len, int *type)
210 {
211 	const char *s;
212 
213 	if ((s = strrchr(file, '/')) == NULL)
214 		s = file;
215 	else
216 		s = s + 1;
217 	*len = strlen(s);
218 	if (*len > 7 && strncmp(s + *len - 7, ";type=", 6) == 0) {
219 		*type = s[*len - 1];
220 		*len -= 7;
221 	} else {
222 		*type = '\0';
223 	}
224 	return (s);
225 }
226 
227 /*
228  * Get current working directory from the reply to a CWD, PWD or CDUP
229  * command.
230  */
231 static int
232 _ftp_pwd(conn_t *conn, char *pwd, size_t pwdlen)
233 {
234 	char *src, *dst, *end;
235 	int q;
236 
237 	if (conn->err != FTP_WORKING_DIRECTORY &&
238 	    conn->err != FTP_FILE_ACTION_OK)
239 		return (FTP_PROTOCOL_ERROR);
240 	end = conn->buf + conn->buflen;
241 	src = conn->buf + 4;
242 	if (src >= end || *src++ != '"')
243 		return (FTP_PROTOCOL_ERROR);
244 	for (q = 0, dst = pwd; src < end && pwdlen--; ++src) {
245 		if (!q && *src == '"')
246 			q = 1;
247 		else if (q && *src != '"')
248 			break;
249 		else if (q)
250 			*dst++ = '"', q = 0;
251 		else
252 			*dst++ = *src;
253 	}
254 	if (!pwdlen)
255 		return (FTP_PROTOCOL_ERROR);
256 	*dst = '\0';
257 #if 0
258 	DEBUG(fprintf(stderr, "pwd: [%s]\n", pwd));
259 #endif
260 	return (FTP_OK);
261 }
262 
263 /*
264  * Change working directory to the directory that contains the specified
265  * file.
266  */
267 static int
268 _ftp_cwd(conn_t *conn, const char *file)
269 {
270 	const char *beg, *end;
271 	char pwd[PATH_MAX];
272 	int e, i, len;
273 
274 	/* If no slashes in name, no need to change dirs. */
275 	if ((end = strrchr(file, '/')) == NULL)
276 		return (0);
277 	if ((e = _ftp_cmd(conn, "PWD")) != FTP_WORKING_DIRECTORY ||
278 	    (e = _ftp_pwd(conn, pwd, sizeof(pwd))) != FTP_OK) {
279 		_ftp_seterr(e);
280 		return (-1);
281 	}
282 	for (;;) {
283 		len = strlen(pwd);
284 
285 		/* Look for a common prefix between PWD and dir to fetch. */
286 		for (i = 0; i <= len && i <= end - file; ++i)
287 			if (pwd[i] != file[i])
288 				break;
289 #if 0
290 		DEBUG(fprintf(stderr, "have: [%.*s|%s]\n", i, pwd, pwd + i));
291 		DEBUG(fprintf(stderr, "want: [%.*s|%s]\n", i, file, file + i));
292 #endif
293 		/* Keep going up a dir until we have a matching prefix. */
294 		if (pwd[i] == '\0' && (file[i - 1] == '/' || file[i] == '/'))
295 			break;
296 		if ((e = _ftp_cmd(conn, "CDUP")) != FTP_FILE_ACTION_OK ||
297 		    (e = _ftp_cmd(conn, "PWD")) != FTP_WORKING_DIRECTORY ||
298 		    (e = _ftp_pwd(conn, pwd, sizeof(pwd))) != FTP_OK) {
299 			_ftp_seterr(e);
300 			return (-1);
301 		}
302 	}
303 
304 #ifdef FTP_COMBINE_CWDS
305 	/* Skip leading slashes, even "////". */
306 	for (beg = file + i; beg < end && *beg == '/'; ++beg, ++i)
307 		/* nothing */ ;
308 
309 	/* If there is no trailing dir, we're already there. */
310 	if (beg >= end)
311 		return (0);
312 
313 	/* Change to the directory all in one chunk (e.g., foo/bar/baz). */
314 	e = _ftp_cmd(conn, "CWD %.*s", (int)(end - beg), beg);
315 	if (e == FTP_FILE_ACTION_OK)
316 		return (0);
317 #endif /* FTP_COMBINE_CWDS */
318 
319 	/* That didn't work so go back to legacy behavior (multiple CWDs). */
320 	for (beg = file + i; beg < end; beg = file + i + 1) {
321 		while (*beg == '/')
322 			++beg, ++i;
323 		for (++i; file + i < end && file[i] != '/'; ++i)
324 			/* nothing */ ;
325 		e = _ftp_cmd(conn, "CWD %.*s", file + i - beg, beg);
326 		if (e != FTP_FILE_ACTION_OK) {
327 			_ftp_seterr(e);
328 			return (-1);
329 		}
330 	}
331 	return (0);
332 }
333 
334 /*
335  * Set transfer mode and data type
336  */
337 static int
338 _ftp_mode_type(conn_t *conn, int mode, int type)
339 {
340 	int e;
341 
342 	switch (mode) {
343 	case 0:
344 	case 's':
345 		mode = 'S';
346 		/* FALLTHROUGH */
347 	case 'S':
348 		break;
349 	default:
350 		return (FTP_PROTOCOL_ERROR);
351 	}
352 	if ((e = _ftp_cmd(conn, "MODE %c", mode)) != FTP_OK) {
353 		if (mode == 'S') {
354 			/*
355 			 * Stream mode is supposed to be the default - so
356 			 * much so that some servers not only do not
357 			 * support any other mode, but do not support the
358 			 * MODE command at all.
359 			 *
360 			 * If "MODE S" fails, it is unlikely that we
361 			 * previously succeeded in setting a different
362 			 * mode.  Therefore, we simply hope that the
363 			 * server is already in the correct mode, and
364 			 * silently ignore the failure.
365 			 */
366 		} else {
367 			return (e);
368 		}
369 	}
370 
371 	switch (type) {
372 	case 0:
373 	case 'i':
374 		type = 'I';
375 		/* FALLTHROUGH */
376 	case 'I':
377 		break;
378 	case 'a':
379 		type = 'A';
380 		/* FALLTHROUGH */
381 	case 'A':
382 		break;
383 	case 'd':
384 		type = 'D';
385 		/* FALLTHROUGH */
386 	case 'D':
387 		/* can't handle yet */
388 	default:
389 		return (FTP_PROTOCOL_ERROR);
390 	}
391 	if ((e = _ftp_cmd(conn, "TYPE %c", type)) != FTP_OK)
392 		return (e);
393 
394 	return (FTP_OK);
395 }
396 
397 /*
398  * Request and parse file stats
399  */
400 static int
401 _ftp_stat(conn_t *conn, const char *file, struct url_stat *us)
402 {
403 	char *ln;
404 	const char *filename;
405 	int filenamelen, type;
406 	struct tm tm;
407 	time_t t;
408 	int e;
409 
410 	us->size = -1;
411 	us->atime = us->mtime = 0;
412 
413 	filename = _ftp_filename(file, &filenamelen, &type);
414 
415 	if ((e = _ftp_mode_type(conn, 0, type)) != FTP_OK) {
416 		_ftp_seterr(e);
417 		return (-1);
418 	}
419 
420 	e = _ftp_cmd(conn, "SIZE %.*s", filenamelen, filename);
421 	if (e != FTP_FILE_STATUS) {
422 		_ftp_seterr(e);
423 		return (-1);
424 	}
425 	for (ln = conn->buf + 4; *ln && isspace((unsigned)*ln); ln++)
426 		/* nothing */ ;
427 	for (us->size = 0; *ln && isdigit((unsigned)*ln); ln++)
428 		us->size = us->size * 10 + *ln - '0';
429 	if (*ln && !isspace((unsigned)*ln)) {
430 		_ftp_seterr(FTP_PROTOCOL_ERROR);
431 		us->size = -1;
432 		return (-1);
433 	}
434 	if (us->size == 0)
435 		us->size = -1;
436 	DEBUG(fprintf(stderr, "size: [%lld]\n", (long long)us->size));
437 
438 	e = _ftp_cmd(conn, "MDTM %.*s", filenamelen, filename);
439 	if (e != FTP_FILE_STATUS) {
440 		_ftp_seterr(e);
441 		return (-1);
442 	}
443 	for (ln = conn->buf + 4; *ln && isspace((unsigned)*ln); ln++)
444 		/* nothing */ ;
445 	switch (strspn(ln, "0123456789")) {
446 	case 14:
447 		break;
448 	case 15:
449 		ln++;
450 		ln[0] = '2';
451 		ln[1] = '0';
452 		break;
453 	default:
454 		_ftp_seterr(FTP_PROTOCOL_ERROR);
455 		return (-1);
456 	}
457 	if (sscanf(ln, "%04d%02d%02d%02d%02d%02d",
458 	    &tm.tm_year, &tm.tm_mon, &tm.tm_mday,
459 	    &tm.tm_hour, &tm.tm_min, &tm.tm_sec) != 6) {
460 		_ftp_seterr(FTP_PROTOCOL_ERROR);
461 		return (-1);
462 	}
463 	tm.tm_mon--;
464 	tm.tm_year -= 1900;
465 	tm.tm_isdst = -1;
466 	t = timegm(&tm);
467 	if (t == (time_t)-1)
468 		t = time(NULL);
469 	us->mtime = t;
470 	us->atime = t;
471 	DEBUG(fprintf(stderr,
472 	    "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, (unsigned)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, (unsigned)len);
547 	if (w >= 0)
548 		return (w);
549 	if (errno != EINTR)
550 		io->err = errno;
551 	return (-1);
552 }
553 
554 /* ARGSUSED1 */
555 static fpos_t
556 _ftp_seekfn(void *v, fpos_t pos __unused, int whence __unused)
557 {
558 	struct ftpio *io;
559 
560 	io = (struct ftpio *)v;
561 	if (io == NULL) {
562 		errno = EBADF;
563 		return (-1);
564 	}
565 	errno = ESPIPE;
566 	return (-1);
567 }
568 
569 static int
570 _ftp_closefn(void *v)
571 {
572 	struct ftpio *io;
573 	int r;
574 
575 	io = (struct ftpio *)v;
576 	if (io == NULL) {
577 		errno = EBADF;
578 		return (-1);
579 	}
580 	if (io->dir == -1)
581 		return (0);
582 	if (io->cconn == NULL || io->dconn == NULL) {
583 		errno = EBADF;
584 		return (-1);
585 	}
586 	_fetch_close(io->dconn);
587 	io->dir = -1;
588 	io->dconn = NULL;
589 	DEBUG(fprintf(stderr, "Waiting for final status\n"));
590 	r = _ftp_chkerr(io->cconn);
591 	if (io->cconn == cached_connection && io->cconn->ref == 1)
592 		cached_connection = NULL;
593 	_fetch_close(io->cconn);
594 	free(io);
595 	return (r == FTP_TRANSFER_COMPLETE) ? 0 : -1;
596 }
597 
598 static FILE *
599 _ftp_setup(conn_t *cconn, conn_t *dconn, int mode)
600 {
601 	struct ftpio *io;
602 	FILE *f;
603 
604 	if (cconn == NULL || dconn == NULL)
605 		return (NULL);
606 	if ((io = malloc(sizeof(*io))) == NULL)
607 		return (NULL);
608 	io->cconn = cconn;
609 	io->dconn = dconn;
610 	io->dir = mode;
611 	io->eof = io->err = 0;
612 	f = funopen(io, _ftp_readfn, _ftp_writefn, _ftp_seekfn, _ftp_closefn);
613 	if (f == NULL)
614 		free(io);
615 	return (f);
616 }
617 
618 /*
619  * Transfer file
620  */
621 static FILE *
622 _ftp_transfer(conn_t *conn, const char *oper, const char *file,
623     int mode, off_t offset, const char *flags)
624 {
625 	struct sockaddr_storage sa;
626 	struct sockaddr_in6 *sin6;
627 	struct sockaddr_in *sin4;
628 	const char *bindaddr;
629 	const char *filename;
630 	int filenamelen, type;
631 	int low, pasv, verbose;
632 	int e, sd = -1;
633 	socklen_t l;
634 	char *s;
635 	FILE *df;
636 
637 	/* check flags */
638 	low = CHECK_FLAG('l');
639 	pasv = CHECK_FLAG('p');
640 	verbose = CHECK_FLAG('v');
641 
642 	/* passive mode */
643 	if (!pasv)
644 		pasv = ((s = getenv("FTP_PASSIVE_MODE")) != NULL &&
645 		    strncasecmp(s, "no", 2) != 0);
646 
647 	/* isolate filename */
648 	filename = _ftp_filename(file, &filenamelen, &type);
649 
650 	/* set transfer mode and data type */
651 	if ((e = _ftp_mode_type(conn, 0, type)) != FTP_OK)
652 		goto ouch;
653 
654 	/* find our own address, bind, and listen */
655 	l = sizeof(sa);
656 	if (getsockname(conn->sd, (struct sockaddr *)(void *)&sa, &l) == -1)
657 		goto sysouch;
658 	if (sa.ss_family == AF_INET6)
659 		unmappedaddr((struct sockaddr_in6 *)(void *)&sa);
660 
661 	/* open data socket */
662 	if ((sd = socket(sa.ss_family, SOCK_STREAM, IPPROTO_TCP)) == -1) {
663 		_fetch_syserr();
664 		return (NULL);
665 	}
666 
667 	if (pasv) {
668 		u_char addr[64];
669 		char *ln, *p;
670 		unsigned int i;
671 		int port;
672 
673 		/* send PASV command */
674 		if (verbose)
675 			_fetch_info("setting passive mode");
676 		switch (sa.ss_family) {
677 		case AF_INET:
678 			if ((e = _ftp_cmd(conn, "PASV")) != FTP_PASSIVE_MODE)
679 				goto ouch;
680 			break;
681 		case AF_INET6:
682 			if ((e = _ftp_cmd(conn, "EPSV")) != FTP_EPASSIVE_MODE) {
683 				if (e == -1)
684 					goto ouch;
685 				if ((e = _ftp_cmd(conn, "LPSV")) !=
686 				    FTP_LPASSIVE_MODE)
687 					goto ouch;
688 			}
689 			break;
690 		default:
691 			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
692 			goto ouch;
693 		}
694 
695 		/*
696 		 * Find address and port number. The reply to the PASV command
697 		 * is IMHO the one and only weak point in the FTP protocol.
698 		 */
699 		ln = conn->buf;
700 		switch (e) {
701 		case FTP_PASSIVE_MODE:
702 		case FTP_LPASSIVE_MODE:
703 			for (p = ln + 3; *p && !isdigit((unsigned)*p); p++)
704 				/* nothing */ ;
705 			if (!*p) {
706 				e = FTP_PROTOCOL_ERROR;
707 				goto ouch;
708 			}
709 			l = (e == FTP_PASSIVE_MODE ? 6 : 21);
710 			for (i = 0; *p && i < l; i++, p++)
711 				addr[i] = (unsigned char) strtol(p, &p, 10);
712 			if (i < l) {
713 				e = FTP_PROTOCOL_ERROR;
714 				goto ouch;
715 			}
716 			break;
717 		case FTP_EPASSIVE_MODE:
718 			for (p = ln + 3; *p && *p != '('; p++)
719 				/* nothing */ ;
720 			if (!*p) {
721 				e = FTP_PROTOCOL_ERROR;
722 				goto ouch;
723 			}
724 			++p;
725 			if (sscanf(p, "%c%c%c%d%c", &addr[0], &addr[1], &addr[2],
726 				&port, &addr[3]) != 5 ||
727 			    addr[0] != addr[1] ||
728 			    addr[0] != addr[2] || addr[0] != addr[3]) {
729 				e = FTP_PROTOCOL_ERROR;
730 				goto ouch;
731 			}
732 			break;
733 		}
734 
735 		/* seek to required offset */
736 		if (offset)
737 			if (_ftp_cmd(conn, "REST %lu", (u_long)offset) != FTP_FILE_OK)
738 				goto sysouch;
739 
740 		/* construct sockaddr for data socket */
741 		l = sizeof(sa);
742 		if (getpeername(conn->sd, (struct sockaddr *)(void *)&sa, &l) == -1)
743 			goto sysouch;
744 		if (sa.ss_family == AF_INET6)
745 			unmappedaddr((struct sockaddr_in6 *)(void *)&sa);
746 		switch (sa.ss_family) {
747 		case AF_INET6:
748 			sin6 = (struct sockaddr_in6 *)(void *)&sa;
749 			if (e == FTP_EPASSIVE_MODE)
750 				sin6->sin6_port = htons(port);
751 			else {
752 				bcopy(addr + 2, (char *)(void *)&sin6->sin6_addr, 16);
753 				bcopy(addr + 19, (char *)(void *)&sin6->sin6_port, 2);
754 			}
755 			break;
756 		case AF_INET:
757 			sin4 = (struct sockaddr_in *)(void *)&sa;
758 			if (e == FTP_EPASSIVE_MODE)
759 				sin4->sin_port = htons(port);
760 			else {
761 				bcopy(addr, (char *)(void *)&sin4->sin_addr, 4);
762 				bcopy(addr + 4, (char *)(void *)&sin4->sin_port, 2);
763 			}
764 			break;
765 		default:
766 			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
767 			break;
768 		}
769 
770 		/* connect to data port */
771 		if (verbose)
772 			_fetch_info("opening data connection");
773 		bindaddr = getenv("FETCH_BIND_ADDRESS");
774 		if (bindaddr != NULL && *bindaddr != '\0' &&
775 		    _fetch_bind(sd, sa.ss_family, bindaddr) != 0)
776 			goto sysouch;
777 		if (connect(sd, (struct sockaddr *)(void *)&sa, (unsigned)sa.ss_len) == -1)
778 			goto sysouch;
779 
780 		/* make the server initiate the transfer */
781 		if (verbose)
782 			_fetch_info("initiating transfer");
783 		e = _ftp_cmd(conn, "%s %.*s", oper, filenamelen, filename);
784 		if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
785 			goto ouch;
786 
787 	} else {
788 		u_int32_t a;
789 		u_short p;
790 		int arg, d;
791 		char *ap;
792 		char hname[INET6_ADDRSTRLEN];
793 
794 		switch (sa.ss_family) {
795 		case AF_INET6:
796 			((struct sockaddr_in6 *)(void *)&sa)->sin6_port = 0;
797 #ifdef IPV6_PORTRANGE
798 			arg = low ? IPV6_PORTRANGE_DEFAULT : IPV6_PORTRANGE_HIGH;
799 			if (setsockopt(sd, IPPROTO_IPV6, IPV6_PORTRANGE,
800 				(char *)(void *)&arg, sizeof(arg)) == -1)
801 				goto sysouch;
802 #endif
803 			break;
804 		case AF_INET:
805 			((struct sockaddr_in *)(void *)&sa)->sin_port = 0;
806 			arg = low ? IP_PORTRANGE_DEFAULT : IP_PORTRANGE_HIGH;
807 			if (setsockopt(sd, IPPROTO_IP, IP_PORTRANGE,
808 				(char *)(void *)&arg, sizeof(arg)) == -1)
809 				goto sysouch;
810 			break;
811 		}
812 		if (verbose)
813 			_fetch_info("binding data socket");
814 		if (bind(sd, (struct sockaddr *)(void *)&sa, (unsigned) sa.ss_len) == -1)
815 			goto sysouch;
816 		if (listen(sd, 1) == -1)
817 			goto sysouch;
818 
819 		/* find what port we're on and tell the server */
820 		if (getsockname(sd, (struct sockaddr *)(void *)&sa, &l) == -1)
821 			goto sysouch;
822 		switch (sa.ss_family) {
823 		case AF_INET:
824 			sin4 = (struct sockaddr_in *)(void *)&sa;
825 			a = ntohl(sin4->sin_addr.s_addr);
826 			p = ntohs(sin4->sin_port);
827 			e = _ftp_cmd(conn, "PORT %d,%d,%d,%d,%d,%d",
828 			    (a >> 24) & 0xff, (a >> 16) & 0xff,
829 			    (a >> 8) & 0xff, a & 0xff,
830 			    ((unsigned)p >> 8) & 0xff, p & 0xff);
831 			break;
832 		case AF_INET6:
833 #define UC(b)	(((int)b)&0xff)
834 			e = -1;
835 			sin6 = (struct sockaddr_in6 *)(void *)&sa;
836 			sin6->sin6_scope_id = 0;
837 			if (getnameinfo((struct sockaddr *)(void *)&sa,
838 				(unsigned)sa.ss_len,
839 				hname, sizeof(hname),
840 				NULL, 0, NI_NUMERICHOST) == 0) {
841 				e = _ftp_cmd(conn, "EPRT |%d|%s|%d|", 2, hname,
842 				    htons(sin6->sin6_port));
843 				if (e == -1)
844 					goto ouch;
845 			}
846 			if (e != FTP_OK) {
847 				ap = (char *)(void *)&sin6->sin6_addr;
848 				e = _ftp_cmd(conn,
849 				    "LPRT %d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d",
850 				    6, 16,
851 				    UC(ap[0]), UC(ap[1]), UC(ap[2]), UC(ap[3]),
852 				    UC(ap[4]), UC(ap[5]), UC(ap[6]), UC(ap[7]),
853 				    UC(ap[8]), UC(ap[9]), UC(ap[10]), UC(ap[11]),
854 				    UC(ap[12]), UC(ap[13]), UC(ap[14]), UC(ap[15]),
855 				    2,
856 				    ((unsigned)ntohs(sin6->sin6_port) >> 8) & 0xff,
857 				    ntohs(sin6->sin6_port)        & 0xff);
858 			}
859 			break;
860 		default:
861 			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
862 			goto ouch;
863 		}
864 		if (e != FTP_OK)
865 			goto ouch;
866 
867 		/* seek to required offset */
868 		if (offset)
869 			if (_ftp_cmd(conn, "REST %ju", (uintmax_t)offset) != FTP_FILE_OK)
870 				goto sysouch;
871 
872 		/* make the server initiate the transfer */
873 		if (verbose)
874 			_fetch_info("initiating transfer");
875 		e = _ftp_cmd(conn, "%s %.*s", oper, filenamelen, filename);
876 		if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
877 			goto ouch;
878 
879 		/* accept the incoming connection and go to town */
880 		if ((d = accept(sd, NULL, NULL)) == -1)
881 			goto sysouch;
882 		close(sd);
883 		sd = d;
884 	}
885 
886 	if ((df = _ftp_setup(conn, _fetch_reopen(sd), mode)) == NULL)
887 		goto sysouch;
888 	return (df);
889 
890 sysouch:
891 	_fetch_syserr();
892 	if (sd >= 0)
893 		close(sd);
894 	return (NULL);
895 
896 ouch:
897 	if (e != -1)
898 		_ftp_seterr(e);
899 	if (sd >= 0)
900 		close(sd);
901 	return (NULL);
902 }
903 
904 /*
905  * Authenticate
906  */
907 static int
908 _ftp_authenticate(conn_t *conn, struct url *url, struct url *purl)
909 {
910 	const char *user, *pwd, *logname;
911 	char pbuf[MAXHOSTNAMELEN + MAXLOGNAME + 1];
912 	int e, len;
913 
914 	/* XXX FTP_AUTH, and maybe .netrc */
915 
916 	/* send user name and password */
917 	if (url->user[0] == '\0')
918 		_fetch_netrc_auth(url);
919 	user = url->user;
920 	if (*user == '\0')
921 		user = getenv("FTP_LOGIN");
922 	if (user == NULL || *user == '\0')
923 		user = FTP_ANONYMOUS_USER;
924 	if (purl && url->port == _fetch_default_port(url->scheme))
925 		e = _ftp_cmd(conn, "USER %s@%s", user, url->host);
926 	else if (purl)
927 		e = _ftp_cmd(conn, "USER %s@%s@%d", user, url->host, url->port);
928 	else
929 		e = _ftp_cmd(conn, "USER %s", user);
930 
931 	/* did the server request a password? */
932 	if (e == FTP_NEED_PASSWORD) {
933 		pwd = url->pwd;
934 		if (*pwd == '\0')
935 			pwd = getenv("FTP_PASSWORD");
936 		if (pwd == NULL || *pwd == '\0') {
937 			if ((logname = getlogin()) == 0)
938 				logname = FTP_ANONYMOUS_USER;
939 			if ((len = snprintf(pbuf, MAXLOGNAME + 1, "%s@", logname)) < 0)
940 				len = 0;
941 			else if (len > MAXLOGNAME)
942 				len = MAXLOGNAME;
943 			gethostname(pbuf + len, sizeof(pbuf) - len);
944 			pwd = pbuf;
945 		}
946 		e = _ftp_cmd(conn, "PASS %s", pwd);
947 	}
948 
949 	return (e);
950 }
951 
952 /*
953  * Log on to FTP server
954  */
955 static conn_t *
956 _ftp_connect(struct url *url, struct url *purl, const char *flags)
957 {
958 	conn_t *conn;
959 	int e, direct, verbose;
960 #ifdef INET6
961 	int af = AF_UNSPEC;
962 #else
963 	int af = AF_INET;
964 #endif
965 
966 	direct = CHECK_FLAG('d');
967 	verbose = CHECK_FLAG('v');
968 	if (CHECK_FLAG('4'))
969 		af = AF_INET;
970 	else if (CHECK_FLAG('6'))
971 		af = AF_INET6;
972 
973 	if (direct)
974 		purl = NULL;
975 
976 	/* check for proxy */
977 	if (purl) {
978 		/* XXX proxy authentication! */
979 		conn = _fetch_connect(purl->host, purl->port, af, verbose);
980 	} else {
981 		/* no proxy, go straight to target */
982 		conn = _fetch_connect(url->host, url->port, af, verbose);
983 		purl = NULL;
984 	}
985 
986 	/* check connection */
987 	if (conn == NULL)
988 		/* _fetch_connect() has already set an error code */
989 		return (NULL);
990 
991 	/* expect welcome message */
992 	if ((e = _ftp_chkerr(conn)) != FTP_SERVICE_READY)
993 		goto fouch;
994 
995 	/* authenticate */
996 	if ((e = _ftp_authenticate(conn, url, purl)) != FTP_LOGGED_IN)
997 		goto fouch;
998 
999 	/* TODO: Request extended features supported, if any (RFC 3659). */
1000 
1001 	/* done */
1002 	return (conn);
1003 
1004 fouch:
1005 	if (e != -1)
1006 		_ftp_seterr(e);
1007 	_fetch_close(conn);
1008 	return (NULL);
1009 }
1010 
1011 /*
1012  * Disconnect from server
1013  */
1014 static void
1015 _ftp_disconnect(conn_t *conn)
1016 {
1017 	(void)_ftp_cmd(conn, "QUIT");
1018 	if (conn == cached_connection && conn->ref == 1)
1019 		cached_connection = NULL;
1020 	_fetch_close(conn);
1021 }
1022 
1023 /*
1024  * Check if we're already connected
1025  */
1026 static int
1027 _ftp_isconnected(struct url *url)
1028 {
1029 	return (cached_connection
1030 	    && (strcmp(url->host, cached_host.host) == 0)
1031 	    && (strcmp(url->user, cached_host.user) == 0)
1032 	    && (strcmp(url->pwd, cached_host.pwd) == 0)
1033 	    && (url->port == cached_host.port));
1034 }
1035 
1036 /*
1037  * Check the cache, reconnect if no luck
1038  */
1039 static conn_t *
1040 _ftp_cached_connect(struct url *url, struct url *purl, const char *flags)
1041 {
1042 	conn_t *conn;
1043 	int e;
1044 
1045 	/* set default port */
1046 	if (!url->port)
1047 		url->port = _fetch_default_port(url->scheme);
1048 
1049 	/* try to use previously cached connection */
1050 	if (_ftp_isconnected(url)) {
1051 		e = _ftp_cmd(cached_connection, "NOOP");
1052 		if (e == FTP_OK || e == FTP_SYNTAX_ERROR)
1053 			return (_fetch_ref(cached_connection));
1054 	}
1055 
1056 	/* connect to server */
1057 	if ((conn = _ftp_connect(url, purl, flags)) == NULL)
1058 		return (NULL);
1059 	if (cached_connection)
1060 		_ftp_disconnect(cached_connection);
1061 	cached_connection = _fetch_ref(conn);
1062 	memcpy(&cached_host, url, sizeof(*url));
1063 	return (conn);
1064 }
1065 
1066 /*
1067  * Check the proxy settings
1068  */
1069 static struct url *
1070 _ftp_get_proxy(const char *flags)
1071 {
1072 	struct url *purl;
1073 	char *p;
1074 
1075 	if (flags != NULL && strchr(flags, 'd') != NULL)
1076 		return (NULL);
1077 	if (((p = getenv("FTP_PROXY")) || (p = getenv("ftp_proxy")) ||
1078 		(p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
1079 	    *p && (purl = fetchParseURL(p)) != NULL) {
1080 		if (!*purl->scheme) {
1081 			if (getenv("FTP_PROXY") || getenv("ftp_proxy"))
1082 				strcpy(purl->scheme, SCHEME_FTP);
1083 			else
1084 				strcpy(purl->scheme, SCHEME_HTTP);
1085 		}
1086 		if (!purl->port)
1087 			purl->port = _fetch_default_proxy_port(purl->scheme);
1088 		if (strcasecmp(purl->scheme, SCHEME_FTP) == 0 ||
1089 		    strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
1090 			return (purl);
1091 		fetchFreeURL(purl);
1092 	}
1093 	return (NULL);
1094 }
1095 
1096 /*
1097  * Process an FTP request
1098  */
1099 FILE *
1100 _ftp_request(struct url *url, const char *op, struct url_stat *us,
1101     struct url *purl, const char *flags)
1102 {
1103 	conn_t *conn;
1104 	int oflag;
1105 
1106 	/* check if we should use HTTP instead */
1107 	if (purl && strcasecmp(purl->scheme, SCHEME_HTTP) == 0) {
1108 		if (strcmp(op, "STAT") == 0)
1109 			return (_http_request(url, "HEAD", us, purl, flags));
1110 		else if (strcmp(op, "RETR") == 0)
1111 			return (_http_request(url, "GET", us, purl, flags));
1112 		/*
1113 		 * Our HTTP code doesn't support PUT requests yet, so try
1114 		 * a direct connection.
1115 		 */
1116 	}
1117 
1118 	/* connect to server */
1119 	conn = _ftp_cached_connect(url, purl, flags);
1120 	if (purl)
1121 		fetchFreeURL(purl);
1122 	if (conn == NULL)
1123 		return (NULL);
1124 
1125 	/* change directory */
1126 	if (_ftp_cwd(conn, url->doc) == -1)
1127 		return (NULL);
1128 
1129 	/* stat file */
1130 	if (us && _ftp_stat(conn, url->doc, us) == -1
1131 	    && fetchLastErrCode != FETCH_PROTO
1132 	    && fetchLastErrCode != FETCH_UNAVAIL)
1133 		return (NULL);
1134 
1135 	/* just a stat */
1136 	if (strcmp(op, "STAT") == 0)
1137 		return (FILE *)1; /* bogus return value */
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 
1147 /*
1148  * Get and stat file
1149  */
1150 FILE *
1151 fetchXGetFTP(struct url *url, struct url_stat *us, const char *flags)
1152 {
1153 	return (_ftp_request(url, "RETR", us, _ftp_get_proxy(flags), flags));
1154 }
1155 
1156 /*
1157  * Get file
1158  */
1159 FILE *
1160 fetchGetFTP(struct url *url, const char *flags)
1161 {
1162 	return (fetchXGetFTP(url, NULL, flags));
1163 }
1164 
1165 /*
1166  * Put file
1167  */
1168 FILE *
1169 fetchPutFTP(struct url *url, const char *flags)
1170 {
1171 
1172 	return (_ftp_request(url, CHECK_FLAG('a') ? "APPE" : "STOR", NULL,
1173 	    _ftp_get_proxy(flags), flags));
1174 }
1175 
1176 /*
1177  * Get file stats
1178  */
1179 int
1180 fetchStatFTP(struct url *url, struct url_stat *us, const char *flags)
1181 {
1182 	FILE *f;
1183 
1184 	f = _ftp_request(url, "STAT", us, _ftp_get_proxy(flags), flags);
1185 	if (f == NULL)
1186 		return (-1);
1187 	return (0);
1188 }
1189 
1190 /*
1191  * List a directory
1192  */
1193 /* ARGSUSED0 */
1194 struct url_ent *
1195 fetchListFTP(struct url *url __unused, const char *flags __unused)
1196 {
1197 	warnx("fetchListFTP(): not implemented");
1198 	return (NULL);
1199 }
1200