xref: /netbsd-src/external/bsd/fetch/dist/libfetch/ftp.c (revision 1ca06f9c9235889e2ff6dc77279d01d151d70a9a)
1 /*	$NetBSD: ftp.c,v 1.1.1.8 2009/10/15 12:59:59 joerg Exp $	*/
2 /*-
3  * Copyright (c) 1998-2004 Dag-Erling Co�dan Sm�rgrav
4  * Copyright (c) 2008, 2009 Joerg Sonnenberger <joerg@NetBSD.org>
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: ftp.c,v 1.101 2008/01/23 20:57:59 des Exp $
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 Co�dan Sm�rgrav
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 #ifdef __linux__
61 /* Keep this down to Linux, it can create surprises else where. */
62 #define _GNU_SOURCE
63 #endif
64 
65 #if HAVE_CONFIG_H
66 #include "config.h"
67 #endif
68 #ifndef NETBSD
69 #include <nbcompat.h>
70 #endif
71 
72 #include <sys/types.h>
73 #include <sys/socket.h>
74 
75 #include <netinet/in.h>
76 #include <arpa/inet.h>
77 
78 #include <ctype.h>
79 #include <errno.h>
80 #include <fcntl.h>
81 #if defined(HAVE_INTTYPES_H) || defined(NETBSD)
82 #include <inttypes.h>
83 #endif
84 #include <stdarg.h>
85 #ifndef NETBSD
86 #include <nbcompat/netdb.h>
87 #include <nbcompat/stdio.h>
88 #else
89 #include <netdb.h>
90 #include <stdio.h>
91 #endif
92 #include <stdlib.h>
93 #include <string.h>
94 #include <time.h>
95 #include <unistd.h>
96 
97 #include "fetch.h"
98 #include "common.h"
99 #include "ftperr.h"
100 
101 #define FTP_ANONYMOUS_USER	"anonymous"
102 
103 #define FTP_CONNECTION_ALREADY_OPEN	125
104 #define FTP_OPEN_DATA_CONNECTION	150
105 #define FTP_OK				200
106 #define FTP_FILE_STATUS			213
107 #define FTP_SERVICE_READY		220
108 #define FTP_TRANSFER_COMPLETE		226
109 #define FTP_PASSIVE_MODE		227
110 #define FTP_LPASSIVE_MODE		228
111 #define FTP_EPASSIVE_MODE		229
112 #define FTP_LOGGED_IN			230
113 #define FTP_FILE_ACTION_OK		250
114 #define FTP_DIRECTORY_CREATED		257 /* multiple meanings */
115 #define FTP_FILE_CREATED		257 /* multiple meanings */
116 #define FTP_WORKING_DIRECTORY		257 /* multiple meanings */
117 #define FTP_NEED_PASSWORD		331
118 #define FTP_NEED_ACCOUNT		332
119 #define FTP_FILE_OK			350
120 #define FTP_SYNTAX_ERROR		500
121 #define FTP_PROTOCOL_ERROR		999
122 
123 static struct url cached_host;
124 static conn_t	*cached_connection;
125 
126 #define isftpreply(foo)				\
127 	(isdigit((unsigned char)foo[0]) &&	\
128 	    isdigit((unsigned char)foo[1]) &&	\
129 	    isdigit((unsigned char)foo[2]) &&	\
130 	    (foo[3] == ' ' || foo[3] == '\0'))
131 #define isftpinfo(foo) \
132 	(isdigit((unsigned char)foo[0]) &&	\
133 	    isdigit((unsigned char)foo[1]) &&	\
134 	    isdigit((unsigned char)foo[2]) &&	\
135 	    foo[3] == '-')
136 
137 /*
138  * Translate IPv4 mapped IPv6 address to IPv4 address
139  */
140 static void
141 unmappedaddr(struct sockaddr_in6 *sin6, socklen_t *len)
142 {
143 	struct sockaddr_in *sin4;
144 	uint32_t addr;
145 	int port;
146 
147 	if (sin6->sin6_family != AF_INET6 ||
148 	    !IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
149 		return;
150 	sin4 = (struct sockaddr_in *)sin6;
151 	addr = *(uint32_t *)&sin6->sin6_addr.s6_addr[12];
152 	port = sin6->sin6_port;
153 	memset(sin4, 0, sizeof(struct sockaddr_in));
154 	sin4->sin_addr.s_addr = addr;
155 	sin4->sin_port = port;
156 	sin4->sin_family = AF_INET;
157 	*len = sizeof(struct sockaddr_in);
158 #ifdef HAVE_SA_LEN
159 	sin4->sin_len = sizeof(struct sockaddr_in);
160 #endif
161 }
162 
163 /*
164  * Get server response
165  */
166 static int
167 ftp_chkerr(conn_t *conn)
168 {
169 	if (fetch_getln(conn) == -1) {
170 		fetch_syserr();
171 		return (-1);
172 	}
173 	if (isftpinfo(conn->buf)) {
174 		while (conn->buflen && !isftpreply(conn->buf)) {
175 			if (fetch_getln(conn) == -1) {
176 				fetch_syserr();
177 				return (-1);
178 			}
179 		}
180 	}
181 
182 	while (conn->buflen &&
183 	    isspace((unsigned char)conn->buf[conn->buflen - 1]))
184 		conn->buflen--;
185 	conn->buf[conn->buflen] = '\0';
186 
187 	if (!isftpreply(conn->buf)) {
188 		ftp_seterr(FTP_PROTOCOL_ERROR);
189 		return (-1);
190 	}
191 
192 	conn->err = (conn->buf[0] - '0') * 100
193 	    + (conn->buf[1] - '0') * 10
194 	    + (conn->buf[2] - '0');
195 
196 	return (conn->err);
197 }
198 
199 /*
200  * Send a command and check reply
201  */
202 static int
203 ftp_cmd(conn_t *conn, const char *fmt, ...)
204 {
205 	va_list ap;
206 	size_t len;
207 	char *msg;
208 	int r;
209 
210 	va_start(ap, fmt);
211 	len = vasprintf(&msg, fmt, ap);
212 	va_end(ap);
213 
214 	if (msg == NULL) {
215 		errno = ENOMEM;
216 		fetch_syserr();
217 		return (-1);
218 	}
219 
220 	r = fetch_putln(conn, msg, len);
221 	free(msg);
222 
223 	if (r == -1) {
224 		fetch_syserr();
225 		return (-1);
226 	}
227 
228 	return (ftp_chkerr(conn));
229 }
230 
231 /*
232  * Return a pointer to the filename part of a path
233  */
234 static const char *
235 ftp_filename(const char *file, int *len, int *type, int subdir)
236 {
237 	const char *s;
238 
239 	if ((s = strrchr(file, '/')) == NULL || subdir)
240 		s = file;
241 	else
242 		s = s + 1;
243 	*len = strlen(s);
244 	if (*len > 7 && strncmp(s + *len - 7, ";type=", 6) == 0) {
245 		*type = s[*len - 1];
246 		*len -= 7;
247 	} else {
248 		*type = '\0';
249 	}
250 	return (s);
251 }
252 
253 /*
254  * Get current working directory from the reply to a CWD, PWD or CDUP
255  * command.
256  */
257 static int
258 ftp_pwd(conn_t *conn, char *pwd, size_t pwdlen)
259 {
260 	char *src, *dst, *end;
261 	int q;
262 
263 	if (conn->err != FTP_WORKING_DIRECTORY &&
264 	    conn->err != FTP_FILE_ACTION_OK)
265 		return (FTP_PROTOCOL_ERROR);
266 	end = conn->buf + conn->buflen;
267 	src = conn->buf + 4;
268 	if (src >= end || *src++ != '"')
269 		return (FTP_PROTOCOL_ERROR);
270 	for (q = 0, dst = pwd; src < end && pwdlen--; ++src) {
271 		if (!q && *src == '"')
272 			q = 1;
273 		else if (q && *src != '"')
274 			break;
275 		else if (q)
276 			*dst++ = '"', q = 0;
277 		else
278 			*dst++ = *src;
279 	}
280 	if (!pwdlen)
281 		return (FTP_PROTOCOL_ERROR);
282 	*dst = '\0';
283 	return (FTP_OK);
284 }
285 
286 /*
287  * Change working directory to the directory that contains the specified
288  * file.
289  */
290 static int
291 ftp_cwd(conn_t *conn, const char *file, int subdir)
292 {
293 	const char *beg, *end;
294 	char pwd[PATH_MAX];
295 	int e, i, len;
296 
297 	/* If no slashes in name, no need to change dirs. */
298 	if (subdir)
299 		end = file + strlen(file);
300 	else if ((end = strrchr(file, '/')) == NULL)
301 		return (0);
302 	if ((e = ftp_cmd(conn, "PWD")) != FTP_WORKING_DIRECTORY ||
303 	    (e = ftp_pwd(conn, pwd, sizeof(pwd))) != FTP_OK) {
304 		ftp_seterr(e);
305 		return (-1);
306 	}
307 	for (;;) {
308 		len = strlen(pwd);
309 
310 		/* Look for a common prefix between PWD and dir to fetch. */
311 		for (i = 0; i <= len && i <= end - file; ++i)
312 			if (pwd[i] != file[i])
313 				break;
314 		/* Keep going up a dir until we have a matching prefix. */
315 		if (strcmp(pwd, "/") == 0)
316 			break;
317 		if (pwd[i] == '\0' && (file[i - 1] == '/' || file[i] == '/'))
318 			break;
319 		if ((e = ftp_cmd(conn, "CDUP")) != FTP_FILE_ACTION_OK ||
320 		    (e = ftp_cmd(conn, "PWD")) != FTP_WORKING_DIRECTORY ||
321 		    (e = ftp_pwd(conn, pwd, sizeof(pwd))) != FTP_OK) {
322 			ftp_seterr(e);
323 			return (-1);
324 		}
325 	}
326 
327 #ifdef FTP_COMBINE_CWDS
328 	/* Skip leading slashes, even "////". */
329 	for (beg = file + i; beg < end && *beg == '/'; ++beg, ++i)
330 		/* nothing */ ;
331 
332 	/* If there is no trailing dir, we're already there. */
333 	if (beg >= end)
334 		return (0);
335 
336 	/* Change to the directory all in one chunk (e.g., foo/bar/baz). */
337 	e = ftp_cmd(conn, "CWD %.*s", (int)(end - beg), beg);
338 	if (e == FTP_FILE_ACTION_OK)
339 		return (0);
340 #endif /* FTP_COMBINE_CWDS */
341 
342 	/* That didn't work so go back to legacy behavior (multiple CWDs). */
343 	for (beg = file + i; beg < end; beg = file + i + 1) {
344 		while (*beg == '/')
345 			++beg, ++i;
346 		for (++i; file + i < end && file[i] != '/'; ++i)
347 			/* nothing */ ;
348 		e = ftp_cmd(conn, "CWD %.*s", file + i - beg, beg);
349 		if (e != FTP_FILE_ACTION_OK) {
350 			ftp_seterr(e);
351 			return (-1);
352 		}
353 	}
354 	return (0);
355 }
356 
357 /*
358  * Set transfer mode and data type
359  */
360 static int
361 ftp_mode_type(conn_t *conn, int mode, int type)
362 {
363 	int e;
364 
365 	switch (mode) {
366 	case 0:
367 	case 's':
368 		mode = 'S';
369 	case 'S':
370 		break;
371 	default:
372 		return (FTP_PROTOCOL_ERROR);
373 	}
374 	if ((e = ftp_cmd(conn, "MODE %c", mode)) != FTP_OK) {
375 		if (mode == 'S') {
376 			/*
377 			 * Stream mode is supposed to be the default - so
378 			 * much so that some servers not only do not
379 			 * support any other mode, but do not support the
380 			 * MODE command at all.
381 			 *
382 			 * If "MODE S" fails, it is unlikely that we
383 			 * previously succeeded in setting a different
384 			 * mode.  Therefore, we simply hope that the
385 			 * server is already in the correct mode, and
386 			 * silently ignore the failure.
387 			 */
388 		} else {
389 			return (e);
390 		}
391 	}
392 
393 	switch (type) {
394 	case 0:
395 	case 'i':
396 		type = 'I';
397 	case 'I':
398 		break;
399 	case 'a':
400 		type = 'A';
401 	case 'A':
402 		break;
403 	case 'd':
404 		type = 'D';
405 	case 'D':
406 		/* can't handle yet */
407 	default:
408 		return (FTP_PROTOCOL_ERROR);
409 	}
410 	if ((e = ftp_cmd(conn, "TYPE %c", type)) != FTP_OK)
411 		return (e);
412 
413 	return (FTP_OK);
414 }
415 
416 /*
417  * Request and parse file stats
418  */
419 static int
420 ftp_stat(conn_t *conn, const char *file, struct url_stat *us)
421 {
422 	char *ln;
423 	const char *filename;
424 	int filenamelen, type;
425 	struct tm tm;
426 	time_t t;
427 	int e;
428 
429 	us->size = -1;
430 	us->atime = us->mtime = 0;
431 
432 	filename = ftp_filename(file, &filenamelen, &type, 0);
433 
434 	if ((e = ftp_mode_type(conn, 0, type)) != FTP_OK) {
435 		ftp_seterr(e);
436 		return (-1);
437 	}
438 
439 	e = ftp_cmd(conn, "SIZE %.*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 	for (us->size = 0; *ln && isdigit((unsigned char)*ln); ln++)
447 		us->size = us->size * 10 + *ln - '0';
448 	if (*ln && !isspace((unsigned char)*ln)) {
449 		ftp_seterr(FTP_PROTOCOL_ERROR);
450 		us->size = -1;
451 		return (-1);
452 	}
453 	if (us->size == 0)
454 		us->size = -1;
455 
456 	e = ftp_cmd(conn, "MDTM %.*s", filenamelen, filename);
457 	if (e != FTP_FILE_STATUS) {
458 		ftp_seterr(e);
459 		return (-1);
460 	}
461 	for (ln = conn->buf + 4; *ln && isspace((unsigned char)*ln); ln++)
462 		/* nothing */ ;
463 	switch (strspn(ln, "0123456789")) {
464 	case 14:
465 		break;
466 	case 15:
467 		ln++;
468 		ln[0] = '2';
469 		ln[1] = '0';
470 		break;
471 	default:
472 		ftp_seterr(FTP_PROTOCOL_ERROR);
473 		return (-1);
474 	}
475 	if (sscanf(ln, "%04d%02d%02d%02d%02d%02d",
476 	    &tm.tm_year, &tm.tm_mon, &tm.tm_mday,
477 	    &tm.tm_hour, &tm.tm_min, &tm.tm_sec) != 6) {
478 		ftp_seterr(FTP_PROTOCOL_ERROR);
479 		return (-1);
480 	}
481 	tm.tm_mon--;
482 	tm.tm_year -= 1900;
483 	tm.tm_isdst = -1;
484 	t = timegm(&tm);
485 	if (t == (time_t)-1)
486 		t = time(NULL);
487 	us->mtime = t;
488 	us->atime = t;
489 
490 	return (0);
491 }
492 
493 /*
494  * I/O functions for FTP
495  */
496 struct ftpio {
497 	conn_t	*cconn;		/* Control connection */
498 	conn_t	*dconn;		/* Data connection */
499 	int	 dir;		/* Direction */
500 	int	 eof;		/* EOF reached */
501 	int	 err;		/* Error code */
502 };
503 
504 static ssize_t	 ftp_readfn(void *, void *, size_t);
505 static ssize_t	 ftp_writefn(void *, const void *, size_t);
506 static void	 ftp_closefn(void *);
507 
508 static ssize_t
509 ftp_readfn(void *v, void *buf, size_t len)
510 {
511 	struct ftpio *io;
512 	int r;
513 
514 	io = (struct ftpio *)v;
515 	if (io == NULL) {
516 		errno = EBADF;
517 		return (-1);
518 	}
519 	if (io->cconn == NULL || io->dconn == NULL || io->dir == O_WRONLY) {
520 		errno = EBADF;
521 		return (-1);
522 	}
523 	if (io->err) {
524 		errno = io->err;
525 		return (-1);
526 	}
527 	if (io->eof)
528 		return (0);
529 	r = fetch_read(io->dconn, buf, len);
530 	if (r > 0)
531 		return (r);
532 	if (r == 0) {
533 		io->eof = 1;
534 		return (0);
535 	}
536 	if (errno != EINTR)
537 		io->err = errno;
538 	return (-1);
539 }
540 
541 static ssize_t
542 ftp_writefn(void *v, const void *buf, size_t len)
543 {
544 	struct ftpio *io;
545 	int w;
546 
547 	io = (struct ftpio *)v;
548 	if (io == NULL) {
549 		errno = EBADF;
550 		return (-1);
551 	}
552 	if (io->cconn == NULL || io->dconn == NULL || io->dir == O_RDONLY) {
553 		errno = EBADF;
554 		return (-1);
555 	}
556 	if (io->err) {
557 		errno = io->err;
558 		return (-1);
559 	}
560 	w = fetch_write(io->dconn, buf, len);
561 	if (w >= 0)
562 		return (w);
563 	if (errno != EINTR)
564 		io->err = errno;
565 	return (-1);
566 }
567 
568 static void
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;
578 	}
579 	if (io->dir == -1)
580 		return;
581 	if (io->cconn == NULL || io->dconn == NULL) {
582 		errno = EBADF;
583 		return;
584 	}
585 	fetch_close(io->dconn);
586 	io->dir = -1;
587 	io->dconn->is_active = 0;
588 	io->dconn = NULL;
589 	r = ftp_chkerr(io->cconn);
590 	if (io->cconn == cached_connection && io->cconn->ref == 1) {
591 		free(cached_host.doc);
592 		cached_connection = NULL;
593 	}
594 	fetch_close(io->cconn);
595 	free(io);
596 	return;
597 }
598 
599 static fetchIO *
600 ftp_setup(conn_t *cconn, conn_t *dconn, int mode)
601 {
602 	struct ftpio *io;
603 	fetchIO *f;
604 
605 	if (cconn == NULL || dconn == NULL)
606 		return (NULL);
607 	if ((io = malloc(sizeof(*io))) == NULL)
608 		return (NULL);
609 	io->cconn = cconn;
610 	io->dconn = dconn;
611 	io->dir = mode;
612 	io->eof = io->err = 0;
613 	io->cconn->is_active = 1;
614 	f = fetchIO_unopen(io, ftp_readfn, ftp_writefn, ftp_closefn);
615 	if (f == NULL)
616 		free(io);
617 	return (f);
618 }
619 
620 /*
621  * Transfer file
622  */
623 static fetchIO *
624 ftp_transfer(conn_t *conn, const char *oper, const char *file, const char *op_arg,
625     int mode, off_t offset, const char *flags)
626 {
627 	union anonymous {
628 		struct sockaddr_storage ss;
629 		struct sockaddr sa;
630 		struct sockaddr_in6 sin6;
631 		struct sockaddr_in sin4;
632 	} u;
633 	const char *bindaddr;
634 	const char *filename;
635 	int filenamelen, type;
636 	int low, pasv, verbose;
637 	int e, sd = -1;
638 	socklen_t l;
639 	char *s;
640 	fetchIO *df;
641 
642 	/* check flags */
643 	low = CHECK_FLAG('l');
644 	pasv = !CHECK_FLAG('a');
645 	verbose = CHECK_FLAG('v');
646 
647 	/* passive mode */
648 	if (!pasv)
649 		pasv = ((s = getenv("FTP_PASSIVE_MODE")) != NULL &&
650 		    strncasecmp(s, "no", 2) != 0);
651 
652 	/* isolate filename */
653 	filename = ftp_filename(file, &filenamelen, &type, op_arg != NULL);
654 
655 	/* set transfer mode and data type */
656 	if ((e = ftp_mode_type(conn, 0, type)) != FTP_OK)
657 		goto ouch;
658 
659 	/* find our own address, bind, and listen */
660 	l = sizeof(u.ss);
661 	if (getsockname(conn->sd, &u.sa, &l) == -1)
662 		goto sysouch;
663 	if (u.ss.ss_family == AF_INET6)
664 		unmappedaddr(&u.sin6, &l);
665 
666 retry_mode:
667 
668 	/* open data socket */
669 	if ((sd = socket(u.ss.ss_family, SOCK_STREAM, IPPROTO_TCP)) == -1) {
670 		fetch_syserr();
671 		return (NULL);
672 	}
673 
674 	if (pasv) {
675 		unsigned char addr[64];
676 		char *ln, *p;
677 		unsigned int i;
678 		int port;
679 
680 		/* send PASV command */
681 		if (verbose)
682 			fetch_info("setting passive mode");
683 		switch (u.ss.ss_family) {
684 		case AF_INET:
685 			if ((e = ftp_cmd(conn, "PASV")) != FTP_PASSIVE_MODE)
686 				goto ouch;
687 			break;
688 		case AF_INET6:
689 			if ((e = ftp_cmd(conn, "EPSV")) != FTP_EPASSIVE_MODE) {
690 				if (e == -1)
691 					goto ouch;
692 				if ((e = ftp_cmd(conn, "LPSV")) !=
693 				    FTP_LPASSIVE_MODE)
694 					goto ouch;
695 			}
696 			break;
697 		default:
698 			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
699 			goto ouch;
700 		}
701 
702 		/*
703 		 * Find address and port number. The reply to the PASV command
704 		 * is IMHO the one and only weak point in the FTP protocol.
705 		 */
706 		ln = conn->buf;
707 		switch (e) {
708 		case FTP_PASSIVE_MODE:
709 		case FTP_LPASSIVE_MODE:
710 			for (p = ln + 3; *p && !isdigit((unsigned char)*p); p++)
711 				/* nothing */ ;
712 			if (!*p) {
713 				e = FTP_PROTOCOL_ERROR;
714 				goto ouch;
715 			}
716 			l = (e == FTP_PASSIVE_MODE ? 6 : 21);
717 			for (i = 0; *p && i < l; i++, p++)
718 				addr[i] = strtol(p, &p, 10);
719 			if (i < l) {
720 				e = FTP_PROTOCOL_ERROR;
721 				goto ouch;
722 			}
723 			break;
724 		case FTP_EPASSIVE_MODE:
725 			for (p = ln + 3; *p && *p != '('; p++)
726 				/* nothing */ ;
727 			if (!*p) {
728 				e = FTP_PROTOCOL_ERROR;
729 				goto ouch;
730 			}
731 			++p;
732 			if (sscanf(p, "%c%c%c%d%c", &addr[0], &addr[1], &addr[2],
733 				&port, &addr[3]) != 5 ||
734 			    addr[0] != addr[1] ||
735 			    addr[0] != addr[2] || addr[0] != addr[3]) {
736 				e = FTP_PROTOCOL_ERROR;
737 				goto ouch;
738 			}
739 			break;
740 		case FTP_SYNTAX_ERROR:
741 			if (verbose)
742 				fetch_info("passive mode failed");
743 			/* Close socket and retry with passive mode. */
744 			pasv = 0;
745 			close(sd);
746 			sd = -1;
747 			goto retry_mode;
748 		}
749 
750 		/* seek to required offset */
751 		if (offset)
752 			if (ftp_cmd(conn, "REST %lu", (unsigned long)offset) != FTP_FILE_OK)
753 				goto sysouch;
754 
755 		/* construct sockaddr for data socket */
756 		l = sizeof(u.ss);
757 		if (getpeername(conn->sd, &u.sa, &l) == -1)
758 			goto sysouch;
759 		if (u.ss.ss_family == AF_INET6)
760 			unmappedaddr(&u.sin6, &l);
761 		switch (u.ss.ss_family) {
762 		case AF_INET6:
763 			if (e == FTP_EPASSIVE_MODE)
764 				u.sin6.sin6_port = htons(port);
765 			else {
766 				memcpy(&u.sin6.sin6_addr, addr + 2, 16);
767 				memcpy(&u.sin6.sin6_port, addr + 19, 2);
768 			}
769 			break;
770 		case AF_INET:
771 			if (e == FTP_EPASSIVE_MODE)
772 				u.sin4.sin_port = htons(port);
773 			else {
774 				memcpy(&u.sin4.sin_addr, addr, 4);
775 				memcpy(&u.sin4.sin_port, addr + 4, 2);
776 			}
777 			break;
778 		default:
779 			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
780 			break;
781 		}
782 
783 		/* connect to data port */
784 		if (verbose)
785 			fetch_info("opening data connection");
786 		bindaddr = getenv("FETCH_BIND_ADDRESS");
787 		if (bindaddr != NULL && *bindaddr != '\0' &&
788 		    fetch_bind(sd, u.ss.ss_family, bindaddr) != 0)
789 			goto sysouch;
790 		if (connect(sd, &u.sa, l) == -1)
791 			goto sysouch;
792 
793 		/* make the server initiate the transfer */
794 		if (verbose)
795 			fetch_info("initiating transfer");
796 		if (op_arg)
797 			e = ftp_cmd(conn, "%s%s%s", oper, *op_arg ? " " : "", op_arg);
798 		else
799 			e = ftp_cmd(conn, "%s %.*s", oper,
800 			    filenamelen, filename);
801 		if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
802 			goto ouch;
803 
804 	} else {
805 		uint32_t a;
806 		uint16_t p;
807 #if defined(IPV6_PORTRANGE) || defined(IP_PORTRANGE)
808 		int arg;
809 #endif
810 		int d;
811 		char *ap;
812 		char hname[INET6_ADDRSTRLEN];
813 
814 		switch (u.ss.ss_family) {
815 		case AF_INET6:
816 			u.sin6.sin6_port = 0;
817 #ifdef IPV6_PORTRANGE
818 			arg = low ? IPV6_PORTRANGE_DEFAULT : IPV6_PORTRANGE_HIGH;
819 			if (setsockopt(sd, IPPROTO_IPV6, IPV6_PORTRANGE,
820 				(char *)&arg, sizeof(arg)) == -1)
821 				goto sysouch;
822 #endif
823 			break;
824 		case AF_INET:
825 			u.sin4.sin_port = 0;
826 #ifdef IP_PORTRANGE
827 			arg = low ? IP_PORTRANGE_DEFAULT : IP_PORTRANGE_HIGH;
828 			if (setsockopt(sd, IPPROTO_IP, IP_PORTRANGE,
829 				(char *)&arg, sizeof(arg)) == -1)
830 				goto sysouch;
831 #endif
832 			break;
833 		}
834 		if (verbose)
835 			fetch_info("binding data socket");
836 		if (bind(sd, &u.sa, l) == -1)
837 			goto sysouch;
838 		if (listen(sd, 1) == -1)
839 			goto sysouch;
840 
841 		/* find what port we're on and tell the server */
842 		if (getsockname(sd, &u.sa, &l) == -1)
843 			goto sysouch;
844 		switch (u.ss.ss_family) {
845 		case AF_INET:
846 			a = ntohl(u.sin4.sin_addr.s_addr);
847 			p = ntohs(u.sin4.sin_port);
848 			e = ftp_cmd(conn, "PORT %d,%d,%d,%d,%d,%d",
849 			    (a >> 24) & 0xff, (a >> 16) & 0xff,
850 			    (a >> 8) & 0xff, a & 0xff,
851 			    (p >> 8) & 0xff, p & 0xff);
852 			break;
853 		case AF_INET6:
854 #define UC(b)	(((int)b)&0xff)
855 			e = -1;
856 			u.sin6.sin6_scope_id = 0;
857 			if (getnameinfo(&u.sa, l,
858 				hname, sizeof(hname),
859 				NULL, 0, NI_NUMERICHOST) == 0) {
860 				e = ftp_cmd(conn, "EPRT |%d|%s|%d|", 2, hname,
861 				    htons(u.sin6.sin6_port));
862 				if (e == -1)
863 					goto ouch;
864 			}
865 			if (e != FTP_OK) {
866 				ap = (char *)&u.sin6.sin6_addr;
867 				e = ftp_cmd(conn,
868 				    "LPRT %d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d",
869 				    6, 16,
870 				    UC(ap[0]), UC(ap[1]), UC(ap[2]), UC(ap[3]),
871 				    UC(ap[4]), UC(ap[5]), UC(ap[6]), UC(ap[7]),
872 				    UC(ap[8]), UC(ap[9]), UC(ap[10]), UC(ap[11]),
873 				    UC(ap[12]), UC(ap[13]), UC(ap[14]), UC(ap[15]),
874 				    2,
875 				    (ntohs(u.sin6.sin6_port) >> 8) & 0xff,
876 				    ntohs(u.sin6.sin6_port)        & 0xff);
877 			}
878 			break;
879 		default:
880 			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
881 			goto ouch;
882 		}
883 		if (e != FTP_OK)
884 			goto ouch;
885 
886 		/* seek to required offset */
887 		if (offset)
888 			if (ftp_cmd(conn, "REST %llu", (unsigned long long)offset) != FTP_FILE_OK)
889 				goto sysouch;
890 
891 		/* make the server initiate the transfer */
892 		if (verbose)
893 			fetch_info("initiating transfer");
894 		if (op_arg)
895 			e = ftp_cmd(conn, "%s%s%s", oper, *op_arg ? " " : "", op_arg);
896 		else
897 			e = ftp_cmd(conn, "%s %.*s", oper,
898 			    filenamelen, filename);
899 		if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
900 			goto ouch;
901 
902 		/* accept the incoming connection and go to town */
903 		if ((d = accept(sd, NULL, NULL)) == -1)
904 			goto sysouch;
905 		close(sd);
906 		sd = d;
907 	}
908 
909 	if ((df = ftp_setup(conn, fetch_reopen(sd), mode)) == NULL)
910 		goto sysouch;
911 	return (df);
912 
913 sysouch:
914 	fetch_syserr();
915 	if (sd >= 0)
916 		close(sd);
917 	return (NULL);
918 
919 ouch:
920 	if (e != -1)
921 		ftp_seterr(e);
922 	if (sd >= 0)
923 		close(sd);
924 	return (NULL);
925 }
926 
927 /*
928  * Authenticate
929  */
930 static int
931 ftp_authenticate(conn_t *conn, struct url *url, struct url *purl)
932 {
933 	const char *user, *pwd, *login_name;
934 	char pbuf[URL_USERLEN + 1 + URL_HOSTLEN + 1];
935 	int e, len;
936 
937 	/* XXX FTP_AUTH, and maybe .netrc */
938 
939 	/* send user name and password */
940 	if (url->user[0] == '\0')
941 		fetch_netrc_auth(url);
942 	user = url->user;
943 	if (*user == '\0')
944 		user = getenv("FTP_LOGIN");
945 	if (user == NULL || *user == '\0')
946 		user = FTP_ANONYMOUS_USER;
947 	if (purl && url->port == fetch_default_port(url->scheme))
948 		e = ftp_cmd(conn, "USER %s@%s", user, url->host);
949 	else if (purl)
950 		e = ftp_cmd(conn, "USER %s@%s@%d", user, url->host, url->port);
951 	else
952 		e = ftp_cmd(conn, "USER %s", user);
953 
954 	/* did the server request a password? */
955 	if (e == FTP_NEED_PASSWORD) {
956 		pwd = url->pwd;
957 		if (*pwd == '\0')
958 			pwd = getenv("FTP_PASSWORD");
959 		if (pwd == NULL || *pwd == '\0') {
960 			if ((login_name = getlogin()) == 0)
961 				login_name = FTP_ANONYMOUS_USER;
962 			if ((len = snprintf(pbuf, URL_USERLEN + 2, "%s@", login_name)) < 0)
963 				len = 0;
964 			else if (len > URL_USERLEN + 1)
965 				len = URL_USERLEN + 1;
966 			gethostname(pbuf + len, sizeof(pbuf) - len);
967 			/* MAXHOSTNAMELEN can differ from URL_HOSTLEN + 1 */
968 			pbuf[sizeof(pbuf) - 1] = '\0';
969 			pwd = pbuf;
970 		}
971 		e = ftp_cmd(conn, "PASS %s", pwd);
972 	}
973 
974 	return (e);
975 }
976 
977 /*
978  * Log on to FTP server
979  */
980 static conn_t *
981 ftp_connect(struct url *url, struct url *purl, const char *flags)
982 {
983 	conn_t *conn;
984 	int e, direct, verbose;
985 #ifdef INET6
986 	int af = AF_UNSPEC;
987 #else
988 	int af = AF_INET;
989 #endif
990 
991 	direct = CHECK_FLAG('d');
992 	verbose = CHECK_FLAG('v');
993 	if (CHECK_FLAG('4'))
994 		af = AF_INET;
995 	else if (CHECK_FLAG('6'))
996 		af = AF_INET6;
997 
998 	if (direct)
999 		purl = NULL;
1000 
1001 	/* check for proxy */
1002 	if (purl) {
1003 		/* XXX proxy authentication! */
1004 		conn = fetch_connect(purl->host, purl->port, af, verbose);
1005 	} else {
1006 		/* no proxy, go straight to target */
1007 		conn = fetch_connect(url->host, url->port, af, verbose);
1008 		purl = NULL;
1009 	}
1010 
1011 	/* check connection */
1012 	if (conn == NULL)
1013 		/* fetch_connect() has already set an error code */
1014 		return (NULL);
1015 
1016 	/* expect welcome message */
1017 	if ((e = ftp_chkerr(conn)) != FTP_SERVICE_READY)
1018 		goto fouch;
1019 
1020 	/* authenticate */
1021 	if ((e = ftp_authenticate(conn, url, purl)) != FTP_LOGGED_IN)
1022 		goto fouch;
1023 
1024 	/* TODO: Request extended features supported, if any (RFC 3659). */
1025 
1026 	/* done */
1027 	return (conn);
1028 
1029 fouch:
1030 	if (e != -1)
1031 		ftp_seterr(e);
1032 	fetch_close(conn);
1033 	return (NULL);
1034 }
1035 
1036 /*
1037  * Disconnect from server
1038  */
1039 static void
1040 ftp_disconnect(conn_t *conn)
1041 {
1042 	(void)ftp_cmd(conn, "QUIT");
1043 	if (conn == cached_connection && conn->ref == 1) {
1044 		free(cached_host.doc);
1045 		cached_host.doc = NULL;
1046 		cached_connection = NULL;
1047 	}
1048 	fetch_close(conn);
1049 }
1050 
1051 /*
1052  * Check if we're already connected
1053  */
1054 static int
1055 ftp_isconnected(struct url *url)
1056 {
1057 	return (cached_connection
1058 	    && (cached_connection->is_active == 0)
1059 	    && (strcmp(url->host, cached_host.host) == 0)
1060 	    && (strcmp(url->user, cached_host.user) == 0)
1061 	    && (strcmp(url->pwd, cached_host.pwd) == 0)
1062 	    && (url->port == cached_host.port));
1063 }
1064 
1065 /*
1066  * Check the cache, reconnect if no luck
1067  */
1068 static conn_t *
1069 ftp_cached_connect(struct url *url, struct url *purl, const char *flags)
1070 {
1071 	char *doc;
1072 	conn_t *conn;
1073 	int e;
1074 
1075 	/* set default port */
1076 	if (!url->port)
1077 		url->port = fetch_default_port(url->scheme);
1078 
1079 	/* try to use previously cached connection */
1080 	if (ftp_isconnected(url)) {
1081 		e = ftp_cmd(cached_connection, "NOOP");
1082 		if (e == FTP_OK || e == FTP_SYNTAX_ERROR)
1083 			return (fetch_ref(cached_connection));
1084 	}
1085 
1086 	/* connect to server */
1087 	if ((conn = ftp_connect(url, purl, flags)) == NULL)
1088 		return (NULL);
1089 	doc = strdup(url->doc);
1090 	if (doc != NULL) {
1091 		if (cached_connection)
1092 			ftp_disconnect(cached_connection);
1093 		cached_connection = fetch_ref(conn);
1094 		memcpy(&cached_host, url, sizeof(*url));
1095 		cached_host.doc = doc;
1096 	}
1097 	return (conn);
1098 }
1099 
1100 /*
1101  * Check the proxy settings
1102  */
1103 static struct url *
1104 ftp_get_proxy(struct url * url, const char *flags)
1105 {
1106 	struct url *purl;
1107 	char *p;
1108 
1109 	if (flags != NULL && strchr(flags, 'd') != NULL)
1110 		return (NULL);
1111 	if (fetch_no_proxy_match(url->host))
1112 		return (NULL);
1113 	if (((p = getenv("FTP_PROXY")) || (p = getenv("ftp_proxy")) ||
1114 		(p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
1115 	    *p && (purl = fetchParseURL(p)) != NULL) {
1116 		if (!*purl->scheme) {
1117 			if (getenv("FTP_PROXY") || getenv("ftp_proxy"))
1118 				strcpy(purl->scheme, SCHEME_FTP);
1119 			else
1120 				strcpy(purl->scheme, SCHEME_HTTP);
1121 		}
1122 		if (!purl->port)
1123 			purl->port = fetch_default_proxy_port(purl->scheme);
1124 		if (strcasecmp(purl->scheme, SCHEME_FTP) == 0 ||
1125 		    strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
1126 			return (purl);
1127 		fetchFreeURL(purl);
1128 	}
1129 	return (NULL);
1130 }
1131 
1132 /*
1133  * Process an FTP request
1134  */
1135 fetchIO *
1136 ftp_request(struct url *url, const char *op, const char *op_arg,
1137     struct url_stat *us, struct url *purl, const char *flags)
1138 {
1139 	fetchIO *f;
1140 	char *path;
1141 	conn_t *conn;
1142 	int if_modified_since, oflag;
1143 	struct url_stat local_us;
1144 
1145 	/* check if we should use HTTP instead */
1146 	if (purl && strcasecmp(purl->scheme, SCHEME_HTTP) == 0) {
1147 		if (strcmp(op, "STAT") == 0)
1148 			return (http_request(url, "HEAD", us, purl, flags));
1149 		else if (strcmp(op, "RETR") == 0)
1150 			return (http_request(url, "GET", us, purl, flags));
1151 		/*
1152 		 * Our HTTP code doesn't support PUT requests yet, so try
1153 		 * a direct connection.
1154 		 */
1155 	}
1156 
1157 	/* connect to server */
1158 	conn = ftp_cached_connect(url, purl, flags);
1159 	if (purl)
1160 		fetchFreeURL(purl);
1161 	if (conn == NULL)
1162 		return (NULL);
1163 
1164 	if ((path = fetchUnquotePath(url)) == NULL) {
1165 		fetch_syserr();
1166 		return NULL;
1167 	}
1168 
1169 	/* change directory */
1170 	if (ftp_cwd(conn, path, op_arg != NULL) == -1) {
1171 		free(path);
1172 		return (NULL);
1173 	}
1174 
1175 	if_modified_since = CHECK_FLAG('i');
1176 	if (if_modified_since && us == NULL)
1177 		us = &local_us;
1178 
1179 	/* stat file */
1180 	if (us && ftp_stat(conn, path, us) == -1
1181 	    && fetchLastErrCode != FETCH_PROTO
1182 	    && fetchLastErrCode != FETCH_UNAVAIL) {
1183 		free(path);
1184 		return (NULL);
1185 	}
1186 
1187 	if (if_modified_since && url->last_modified > 0 &&
1188 	    url->last_modified >= us->mtime) {
1189 		free(path);
1190 		fetchLastErrCode = FETCH_UNCHANGED;
1191 		snprintf(fetchLastErrString, MAXERRSTRING, "Unchanged");
1192 		return NULL;
1193 	}
1194 
1195 	/* just a stat */
1196 	if (strcmp(op, "STAT") == 0) {
1197 		free(path);
1198 		return fetchIO_unopen(NULL, NULL, NULL, NULL);
1199 	}
1200 	if (strcmp(op, "STOR") == 0 || strcmp(op, "APPE") == 0)
1201 		oflag = O_WRONLY;
1202 	else
1203 		oflag = O_RDONLY;
1204 
1205 	/* initiate the transfer */
1206 	f = (ftp_transfer(conn, op, path, op_arg, oflag, url->offset, flags));
1207 	free(path);
1208 	return f;
1209 }
1210 
1211 /*
1212  * Get and stat file
1213  */
1214 fetchIO *
1215 fetchXGetFTP(struct url *url, struct url_stat *us, const char *flags)
1216 {
1217 	return (ftp_request(url, "RETR", NULL, us, ftp_get_proxy(url, flags), flags));
1218 }
1219 
1220 /*
1221  * Get file
1222  */
1223 fetchIO *
1224 fetchGetFTP(struct url *url, const char *flags)
1225 {
1226 	return (fetchXGetFTP(url, NULL, flags));
1227 }
1228 
1229 /*
1230  * Put file
1231  */
1232 fetchIO *
1233 fetchPutFTP(struct url *url, const char *flags)
1234 {
1235 	return (ftp_request(url, CHECK_FLAG('a') ? "APPE" : "STOR", NULL, NULL,
1236 	    ftp_get_proxy(url, flags), flags));
1237 }
1238 
1239 /*
1240  * Get file stats
1241  */
1242 int
1243 fetchStatFTP(struct url *url, struct url_stat *us, const char *flags)
1244 {
1245 	fetchIO *f;
1246 
1247 	f = ftp_request(url, "STAT", NULL, us, ftp_get_proxy(url, flags), flags);
1248 	if (f == NULL)
1249 		return (-1);
1250 	fetchIO_close(f);
1251 	return (0);
1252 }
1253 
1254 /*
1255  * List a directory
1256  */
1257 int
1258 fetchListFTP(struct url_list *ue, struct url *url, const char *pattern, const char *flags)
1259 {
1260 	fetchIO *f;
1261 	char buf[2 * PATH_MAX], *eol, *eos;
1262 	ssize_t len;
1263 	size_t cur_off;
1264 	int ret;
1265 
1266 	/* XXX What about proxies? */
1267 	if (pattern == NULL || strcmp(pattern, "*") == 0)
1268 		pattern = "";
1269 	f = ftp_request(url, "NLST", pattern, NULL, ftp_get_proxy(url, flags), flags);
1270 	if (f == NULL)
1271 		return -1;
1272 
1273 	cur_off = 0;
1274 	ret = 0;
1275 
1276 	while ((len = fetchIO_read(f, buf + cur_off, sizeof(buf) - cur_off)) > 0) {
1277 		cur_off += len;
1278 		while ((eol = memchr(buf, '\n', cur_off)) != NULL) {
1279 			if (len == eol - buf)
1280 				break;
1281 			if (eol != buf) {
1282 				if (eol[-1] == '\r')
1283 					eos = eol - 1;
1284 				else
1285 					eos = eol;
1286 				*eos = '\0';
1287 				ret = fetch_add_entry(ue, url, buf, 0);
1288 				if (ret)
1289 					break;
1290 				cur_off -= eol - buf + 1;
1291 				memmove(buf, eol + 1, cur_off);
1292 			}
1293 		}
1294 		if (ret)
1295 			break;
1296 	}
1297 	if (cur_off != 0 || len < 0) {
1298 		/* Not RFC conform, bail out. */
1299 		fetchIO_close(f);
1300 		return -1;
1301 	}
1302 	fetchIO_close(f);
1303 	return ret;
1304 }
1305