xref: /netbsd-src/external/bsd/fetch/dist/libfetch/ftp.c (revision b5677b36047b601b9addaaa494a58ceae82c2a6c)
1 /*	$NetBSD: ftp.c,v 1.1.1.6 2009/04/04 23:26:05 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 = NULL;
588 	r = ftp_chkerr(io->cconn);
589 	if (io->cconn == cached_connection && io->cconn->ref == 1)
590 		cached_connection = NULL;
591 	fetch_close(io->cconn);
592 	free(io);
593 	return;
594 }
595 
596 static fetchIO *
597 ftp_setup(conn_t *cconn, conn_t *dconn, int mode)
598 {
599 	struct ftpio *io;
600 	fetchIO *f;
601 
602 	if (cconn == NULL || dconn == NULL)
603 		return (NULL);
604 	if ((io = malloc(sizeof(*io))) == NULL)
605 		return (NULL);
606 	io->cconn = cconn;
607 	io->dconn = dconn;
608 	io->dir = mode;
609 	io->eof = io->err = 0;
610 	f = fetchIO_unopen(io, ftp_readfn, ftp_writefn, ftp_closefn);
611 	if (f == NULL)
612 		free(io);
613 	return (f);
614 }
615 
616 /*
617  * Transfer file
618  */
619 static fetchIO *
620 ftp_transfer(conn_t *conn, const char *oper, const char *file, const char *op_arg,
621     int mode, off_t offset, const char *flags)
622 {
623 	struct sockaddr_storage sa;
624 	struct sockaddr_in6 *sin6;
625 	struct sockaddr_in *sin4;
626 	const char *bindaddr;
627 	const char *filename;
628 	int filenamelen, type;
629 	int low, pasv, verbose;
630 	int e, sd = -1;
631 	socklen_t l;
632 	char *s;
633 	fetchIO *df;
634 
635 	/* check flags */
636 	low = CHECK_FLAG('l');
637 	pasv = !CHECK_FLAG('a');
638 	verbose = CHECK_FLAG('v');
639 
640 	/* passive mode */
641 	if (!pasv)
642 		pasv = ((s = getenv("FTP_PASSIVE_MODE")) != NULL &&
643 		    strncasecmp(s, "no", 2) != 0);
644 
645 	/* isolate filename */
646 	filename = ftp_filename(file, &filenamelen, &type, op_arg != NULL);
647 
648 	/* set transfer mode and data type */
649 	if ((e = ftp_mode_type(conn, 0, type)) != FTP_OK)
650 		goto ouch;
651 
652 	/* find our own address, bind, and listen */
653 	l = sizeof(sa);
654 	if (getsockname(conn->sd, (struct sockaddr *)&sa, &l) == -1)
655 		goto sysouch;
656 	if (sa.ss_family == AF_INET6)
657 		unmappedaddr((struct sockaddr_in6 *)&sa, &l);
658 
659 retry_mode:
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 		unsigned 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 char)*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] = 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 		case FTP_SYNTAX_ERROR:
734 			if (verbose)
735 				fetch_info("passive mode failed");
736 			/* Close socket and retry with passive mode. */
737 			pasv = 0;
738 			close(sd);
739 			sd = -1;
740 			goto retry_mode;
741 		}
742 
743 		/* seek to required offset */
744 		if (offset)
745 			if (ftp_cmd(conn, "REST %lu", (unsigned long)offset) != FTP_FILE_OK)
746 				goto sysouch;
747 
748 		/* construct sockaddr for data socket */
749 		l = sizeof(sa);
750 		if (getpeername(conn->sd, (struct sockaddr *)&sa, &l) == -1)
751 			goto sysouch;
752 		if (sa.ss_family == AF_INET6)
753 			unmappedaddr((struct sockaddr_in6 *)&sa, &l);
754 		switch (sa.ss_family) {
755 		case AF_INET6:
756 			sin6 = (struct sockaddr_in6 *)&sa;
757 			if (e == FTP_EPASSIVE_MODE)
758 				sin6->sin6_port = htons(port);
759 			else {
760 				memcpy(&sin6->sin6_addr, addr + 2, 16);
761 				memcpy(&sin6->sin6_port, addr + 19, 2);
762 			}
763 			break;
764 		case AF_INET:
765 			sin4 = (struct sockaddr_in *)&sa;
766 			if (e == FTP_EPASSIVE_MODE)
767 				sin4->sin_port = htons(port);
768 			else {
769 				memcpy(&sin4->sin_addr, addr, 4);
770 				memcpy(&sin4->sin_port, addr + 4, 2);
771 			}
772 			break;
773 		default:
774 			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
775 			break;
776 		}
777 
778 		/* connect to data port */
779 		if (verbose)
780 			fetch_info("opening data connection");
781 		bindaddr = getenv("FETCH_BIND_ADDRESS");
782 		if (bindaddr != NULL && *bindaddr != '\0' &&
783 		    fetch_bind(sd, sa.ss_family, bindaddr) != 0)
784 			goto sysouch;
785 		if (connect(sd, (struct sockaddr *)&sa, l) == -1)
786 			goto sysouch;
787 
788 		/* make the server initiate the transfer */
789 		if (verbose)
790 			fetch_info("initiating transfer");
791 		if (op_arg)
792 			e = ftp_cmd(conn, "%s%s%s", oper, *op_arg ? " " : "", op_arg);
793 		else
794 			e = ftp_cmd(conn, "%s %.*s", oper,
795 			    filenamelen, filename);
796 		if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
797 			goto ouch;
798 
799 	} else {
800 		uint32_t a;
801 		uint16_t p;
802 #if defined(IPV6_PORTRANGE) || defined(IP_PORTRANGE)
803 		int arg;
804 #endif
805 		int d;
806 		char *ap;
807 		char hname[INET6_ADDRSTRLEN];
808 
809 		switch (sa.ss_family) {
810 		case AF_INET6:
811 			((struct sockaddr_in6 *)&sa)->sin6_port = 0;
812 #ifdef IPV6_PORTRANGE
813 			arg = low ? IPV6_PORTRANGE_DEFAULT : IPV6_PORTRANGE_HIGH;
814 			if (setsockopt(sd, IPPROTO_IPV6, IPV6_PORTRANGE,
815 				(char *)&arg, sizeof(arg)) == -1)
816 				goto sysouch;
817 #endif
818 			break;
819 		case AF_INET:
820 			((struct sockaddr_in *)&sa)->sin_port = 0;
821 #ifdef IP_PORTRANGE
822 			arg = low ? IP_PORTRANGE_DEFAULT : IP_PORTRANGE_HIGH;
823 			if (setsockopt(sd, IPPROTO_IP, IP_PORTRANGE,
824 				(char *)&arg, sizeof(arg)) == -1)
825 				goto sysouch;
826 #endif
827 			break;
828 		}
829 		if (verbose)
830 			fetch_info("binding data socket");
831 		if (bind(sd, (struct sockaddr *)&sa, l) == -1)
832 			goto sysouch;
833 		if (listen(sd, 1) == -1)
834 			goto sysouch;
835 
836 		/* find what port we're on and tell the server */
837 		if (getsockname(sd, (struct sockaddr *)&sa, &l) == -1)
838 			goto sysouch;
839 		switch (sa.ss_family) {
840 		case AF_INET:
841 			sin4 = (struct sockaddr_in *)&sa;
842 			a = ntohl(sin4->sin_addr.s_addr);
843 			p = ntohs(sin4->sin_port);
844 			e = ftp_cmd(conn, "PORT %d,%d,%d,%d,%d,%d",
845 			    (a >> 24) & 0xff, (a >> 16) & 0xff,
846 			    (a >> 8) & 0xff, a & 0xff,
847 			    (p >> 8) & 0xff, p & 0xff);
848 			break;
849 		case AF_INET6:
850 #define UC(b)	(((int)b)&0xff)
851 			e = -1;
852 			sin6 = (struct sockaddr_in6 *)&sa;
853 			sin6->sin6_scope_id = 0;
854 			if (getnameinfo((struct sockaddr *)&sa, l,
855 				hname, sizeof(hname),
856 				NULL, 0, NI_NUMERICHOST) == 0) {
857 				e = ftp_cmd(conn, "EPRT |%d|%s|%d|", 2, hname,
858 				    htons(sin6->sin6_port));
859 				if (e == -1)
860 					goto ouch;
861 			}
862 			if (e != FTP_OK) {
863 				ap = (char *)&sin6->sin6_addr;
864 				e = ftp_cmd(conn,
865 				    "LPRT %d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d",
866 				    6, 16,
867 				    UC(ap[0]), UC(ap[1]), UC(ap[2]), UC(ap[3]),
868 				    UC(ap[4]), UC(ap[5]), UC(ap[6]), UC(ap[7]),
869 				    UC(ap[8]), UC(ap[9]), UC(ap[10]), UC(ap[11]),
870 				    UC(ap[12]), UC(ap[13]), UC(ap[14]), UC(ap[15]),
871 				    2,
872 				    (ntohs(sin6->sin6_port) >> 8) & 0xff,
873 				    ntohs(sin6->sin6_port)        & 0xff);
874 			}
875 			break;
876 		default:
877 			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
878 			goto ouch;
879 		}
880 		if (e != FTP_OK)
881 			goto ouch;
882 
883 		/* seek to required offset */
884 		if (offset)
885 			if (ftp_cmd(conn, "REST %llu", (unsigned long long)offset) != FTP_FILE_OK)
886 				goto sysouch;
887 
888 		/* make the server initiate the transfer */
889 		if (verbose)
890 			fetch_info("initiating transfer");
891 		if (op_arg)
892 			e = ftp_cmd(conn, "%s%s%s", oper, *op_arg ? " " : "", op_arg);
893 		else
894 			e = ftp_cmd(conn, "%s %.*s", oper,
895 			    filenamelen, filename);
896 		if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
897 			goto ouch;
898 
899 		/* accept the incoming connection and go to town */
900 		if ((d = accept(sd, NULL, NULL)) == -1)
901 			goto sysouch;
902 		close(sd);
903 		sd = d;
904 	}
905 
906 	if ((df = ftp_setup(conn, fetch_reopen(sd), mode)) == NULL)
907 		goto sysouch;
908 	return (df);
909 
910 sysouch:
911 	fetch_syserr();
912 	if (sd >= 0)
913 		close(sd);
914 	return (NULL);
915 
916 ouch:
917 	if (e != -1)
918 		ftp_seterr(e);
919 	if (sd >= 0)
920 		close(sd);
921 	return (NULL);
922 }
923 
924 /*
925  * Authenticate
926  */
927 static int
928 ftp_authenticate(conn_t *conn, struct url *url, struct url *purl)
929 {
930 	const char *user, *pwd, *login_name;
931 	char pbuf[URL_USERLEN + 1 + URL_HOSTLEN + 1];
932 	int e, len;
933 
934 	/* XXX FTP_AUTH, and maybe .netrc */
935 
936 	/* send user name and password */
937 	if (url->user[0] == '\0')
938 		fetch_netrc_auth(url);
939 	user = url->user;
940 	if (*user == '\0')
941 		user = getenv("FTP_LOGIN");
942 	if (user == NULL || *user == '\0')
943 		user = FTP_ANONYMOUS_USER;
944 	if (purl && url->port == fetch_default_port(url->scheme))
945 		e = ftp_cmd(conn, "USER %s@%s", user, url->host);
946 	else if (purl)
947 		e = ftp_cmd(conn, "USER %s@%s@%d", user, url->host, url->port);
948 	else
949 		e = ftp_cmd(conn, "USER %s", user);
950 
951 	/* did the server request a password? */
952 	if (e == FTP_NEED_PASSWORD) {
953 		pwd = url->pwd;
954 		if (*pwd == '\0')
955 			pwd = getenv("FTP_PASSWORD");
956 		if (pwd == NULL || *pwd == '\0') {
957 			if ((login_name = getlogin()) == 0)
958 				login_name = FTP_ANONYMOUS_USER;
959 			if ((len = snprintf(pbuf, URL_USERLEN + 2, "%s@", login_name)) < 0)
960 				len = 0;
961 			else if (len > URL_USERLEN + 1)
962 				len = URL_USERLEN + 1;
963 			gethostname(pbuf + len, sizeof(pbuf) - len);
964 			/* MAXHOSTNAMELEN can differ from URL_HOSTLEN + 1 */
965 			pbuf[sizeof(pbuf) - 1] = '\0';
966 			pwd = pbuf;
967 		}
968 		e = ftp_cmd(conn, "PASS %s", pwd);
969 	}
970 
971 	return (e);
972 }
973 
974 /*
975  * Log on to FTP server
976  */
977 static conn_t *
978 ftp_connect(struct url *url, struct url *purl, const char *flags)
979 {
980 	conn_t *conn;
981 	int e, direct, verbose;
982 #ifdef INET6
983 	int af = AF_UNSPEC;
984 #else
985 	int af = AF_INET;
986 #endif
987 
988 	direct = CHECK_FLAG('d');
989 	verbose = CHECK_FLAG('v');
990 	if (CHECK_FLAG('4'))
991 		af = AF_INET;
992 	else if (CHECK_FLAG('6'))
993 		af = AF_INET6;
994 
995 	if (direct)
996 		purl = NULL;
997 
998 	/* check for proxy */
999 	if (purl) {
1000 		/* XXX proxy authentication! */
1001 		conn = fetch_connect(purl->host, purl->port, af, verbose);
1002 	} else {
1003 		/* no proxy, go straight to target */
1004 		conn = fetch_connect(url->host, url->port, af, verbose);
1005 		purl = NULL;
1006 	}
1007 
1008 	/* check connection */
1009 	if (conn == NULL)
1010 		/* fetch_connect() has already set an error code */
1011 		return (NULL);
1012 
1013 	/* expect welcome message */
1014 	if ((e = ftp_chkerr(conn)) != FTP_SERVICE_READY)
1015 		goto fouch;
1016 
1017 	/* authenticate */
1018 	if ((e = ftp_authenticate(conn, url, purl)) != FTP_LOGGED_IN)
1019 		goto fouch;
1020 
1021 	/* TODO: Request extended features supported, if any (RFC 3659). */
1022 
1023 	/* done */
1024 	return (conn);
1025 
1026 fouch:
1027 	if (e != -1)
1028 		ftp_seterr(e);
1029 	fetch_close(conn);
1030 	return (NULL);
1031 }
1032 
1033 /*
1034  * Disconnect from server
1035  */
1036 static void
1037 ftp_disconnect(conn_t *conn)
1038 {
1039 	(void)ftp_cmd(conn, "QUIT");
1040 	if (conn == cached_connection && conn->ref == 1)
1041 		cached_connection = NULL;
1042 	fetch_close(conn);
1043 }
1044 
1045 /*
1046  * Check if we're already connected
1047  */
1048 static int
1049 ftp_isconnected(struct url *url)
1050 {
1051 	return (cached_connection
1052 	    && (strcmp(url->host, cached_host.host) == 0)
1053 	    && (strcmp(url->user, cached_host.user) == 0)
1054 	    && (strcmp(url->pwd, cached_host.pwd) == 0)
1055 	    && (url->port == cached_host.port));
1056 }
1057 
1058 /*
1059  * Check the cache, reconnect if no luck
1060  */
1061 static conn_t *
1062 ftp_cached_connect(struct url *url, struct url *purl, const char *flags)
1063 {
1064 	conn_t *conn;
1065 	int e;
1066 
1067 	/* set default port */
1068 	if (!url->port)
1069 		url->port = fetch_default_port(url->scheme);
1070 
1071 	/* try to use previously cached connection */
1072 	if (ftp_isconnected(url)) {
1073 		e = ftp_cmd(cached_connection, "NOOP");
1074 		if (e == FTP_OK || e == FTP_SYNTAX_ERROR)
1075 			return (fetch_ref(cached_connection));
1076 	}
1077 
1078 	/* connect to server */
1079 	if ((conn = ftp_connect(url, purl, flags)) == NULL)
1080 		return (NULL);
1081 	if (cached_connection)
1082 		ftp_disconnect(cached_connection);
1083 	cached_connection = fetch_ref(conn);
1084 	memcpy(&cached_host, url, sizeof(*url));
1085 	return (conn);
1086 }
1087 
1088 /*
1089  * Check the proxy settings
1090  */
1091 static struct url *
1092 ftp_get_proxy(struct url * url, const char *flags)
1093 {
1094 	struct url *purl;
1095 	char *p;
1096 
1097 	if (flags != NULL && strchr(flags, 'd') != NULL)
1098 		return (NULL);
1099 	if (fetch_no_proxy_match(url->host))
1100 		return (NULL);
1101 	if (((p = getenv("FTP_PROXY")) || (p = getenv("ftp_proxy")) ||
1102 		(p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
1103 	    *p && (purl = fetchParseURL(p)) != NULL) {
1104 		if (!*purl->scheme) {
1105 			if (getenv("FTP_PROXY") || getenv("ftp_proxy"))
1106 				strcpy(purl->scheme, SCHEME_FTP);
1107 			else
1108 				strcpy(purl->scheme, SCHEME_HTTP);
1109 		}
1110 		if (!purl->port)
1111 			purl->port = fetch_default_proxy_port(purl->scheme);
1112 		if (strcasecmp(purl->scheme, SCHEME_FTP) == 0 ||
1113 		    strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
1114 			return (purl);
1115 		fetchFreeURL(purl);
1116 	}
1117 	return (NULL);
1118 }
1119 
1120 /*
1121  * Process an FTP request
1122  */
1123 fetchIO *
1124 ftp_request(struct url *url, const char *op, const char *op_arg,
1125     struct url_stat *us, struct url *purl, const char *flags)
1126 {
1127 	fetchIO *f;
1128 	char *path;
1129 	conn_t *conn;
1130 	int if_modified_since, oflag;
1131 	struct url_stat local_us;
1132 
1133 	/* check if we should use HTTP instead */
1134 	if (purl && strcasecmp(purl->scheme, SCHEME_HTTP) == 0) {
1135 		if (strcmp(op, "STAT") == 0)
1136 			return (http_request(url, "HEAD", us, purl, flags));
1137 		else if (strcmp(op, "RETR") == 0)
1138 			return (http_request(url, "GET", us, purl, flags));
1139 		/*
1140 		 * Our HTTP code doesn't support PUT requests yet, so try
1141 		 * a direct connection.
1142 		 */
1143 	}
1144 
1145 	/* connect to server */
1146 	conn = ftp_cached_connect(url, purl, flags);
1147 	if (purl)
1148 		fetchFreeURL(purl);
1149 	if (conn == NULL)
1150 		return (NULL);
1151 
1152 	if ((path = fetchUnquotePath(url)) == NULL) {
1153 		fetch_syserr();
1154 		return NULL;
1155 	}
1156 
1157 	/* change directory */
1158 	if (ftp_cwd(conn, path, op_arg != NULL) == -1) {
1159 		free(path);
1160 		return (NULL);
1161 	}
1162 
1163 	if_modified_since = CHECK_FLAG('i');
1164 	if (if_modified_since && us == NULL)
1165 		us = &local_us;
1166 
1167 	/* stat file */
1168 	if (us && ftp_stat(conn, path, us) == -1
1169 	    && fetchLastErrCode != FETCH_PROTO
1170 	    && fetchLastErrCode != FETCH_UNAVAIL) {
1171 		free(path);
1172 		return (NULL);
1173 	}
1174 
1175 	if (if_modified_since && url->last_modified > 0 &&
1176 	    url->last_modified >= us->mtime) {
1177 		fetchLastErrCode = FETCH_UNCHANGED;
1178 		snprintf(fetchLastErrString, MAXERRSTRING, "Unchanged");
1179 		return NULL;
1180 	}
1181 
1182 	/* just a stat */
1183 	if (strcmp(op, "STAT") == 0)
1184 		return fetchIO_unopen(NULL, NULL, NULL, NULL);
1185 	if (strcmp(op, "STOR") == 0 || strcmp(op, "APPE") == 0)
1186 		oflag = O_WRONLY;
1187 	else
1188 		oflag = O_RDONLY;
1189 
1190 	/* initiate the transfer */
1191 	f = (ftp_transfer(conn, op, path, op_arg, oflag, url->offset, flags));
1192 	free(path);
1193 	return f;
1194 }
1195 
1196 /*
1197  * Get and stat file
1198  */
1199 fetchIO *
1200 fetchXGetFTP(struct url *url, struct url_stat *us, const char *flags)
1201 {
1202 	return (ftp_request(url, "RETR", NULL, us, ftp_get_proxy(url, flags), flags));
1203 }
1204 
1205 /*
1206  * Get file
1207  */
1208 fetchIO *
1209 fetchGetFTP(struct url *url, const char *flags)
1210 {
1211 	return (fetchXGetFTP(url, NULL, flags));
1212 }
1213 
1214 /*
1215  * Put file
1216  */
1217 fetchIO *
1218 fetchPutFTP(struct url *url, const char *flags)
1219 {
1220 	return (ftp_request(url, CHECK_FLAG('a') ? "APPE" : "STOR", NULL, NULL,
1221 	    ftp_get_proxy(url, flags), flags));
1222 }
1223 
1224 /*
1225  * Get file stats
1226  */
1227 int
1228 fetchStatFTP(struct url *url, struct url_stat *us, const char *flags)
1229 {
1230 	fetchIO *f;
1231 
1232 	f = ftp_request(url, "STAT", NULL, us, ftp_get_proxy(url, flags), flags);
1233 	if (f == NULL)
1234 		return (-1);
1235 	fetchIO_close(f);
1236 	return (0);
1237 }
1238 
1239 /*
1240  * List a directory
1241  */
1242 int
1243 fetchListFTP(struct url_list *ue, struct url *url, const char *pattern, const char *flags)
1244 {
1245 	fetchIO *f;
1246 	char buf[2 * PATH_MAX], *eol, *eos;
1247 	ssize_t len;
1248 	size_t cur_off;
1249 
1250 	/* XXX What about proxies? */
1251 	if (pattern == NULL || strcmp(pattern, "*") == 0)
1252 		pattern = "";
1253 	f = ftp_request(url, "NLST", pattern, NULL, ftp_get_proxy(url, flags), flags);
1254 	if (f == NULL)
1255 		return -1;
1256 
1257 	cur_off = 0;
1258 	while ((len = fetchIO_read(f, buf + cur_off, sizeof(buf) - cur_off)) > 0) {
1259 		cur_off += len;
1260 		while ((eol = memchr(buf, '\n', cur_off)) != NULL) {
1261 			if (len == eol - buf)
1262 				break;
1263 			if (eol != buf) {
1264 				if (eol[-1] == '\r')
1265 					eos = eol - 1;
1266 				else
1267 					eos = eol;
1268 				*eos = '\0';
1269 				fetch_add_entry(ue, url, buf, 0);
1270 				cur_off -= eol - buf + 1;
1271 				memmove(buf, eol + 1, cur_off);
1272 			}
1273 		}
1274 	}
1275 	if (cur_off != 0 || len < 0) {
1276 		/* Not RFC conform, bail out. */
1277 		fetchIO_close(f);
1278 		return -1;
1279 	}
1280 	fetchIO_close(f);
1281 	return 0;
1282 }
1283