xref: /netbsd-src/external/bsd/fetch/dist/libfetch/ftp.c (revision 96230fab84e26a6435963032070e916a951a8b2e)
1 /*	$NetBSD: ftp.c,v 1.1.1.2 2008/10/07 15:55:20 joerg Exp $	*/
2 /*-
3  * Copyright (c) 1998-2004 Dag-Erling Co�dan Sm�rgrav
4  * Copyright (c) 2008 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 #if HAVE_CONFIG_H
61 #include "config.h"
62 #endif
63 #ifndef NETBSD
64 #include <nbcompat.h>
65 #endif
66 
67 #include <sys/types.h>
68 #include <sys/socket.h>
69 
70 #include <arpa/inet.h>
71 #include <netinet/in.h>
72 
73 #include <ctype.h>
74 #include <errno.h>
75 #include <fcntl.h>
76 #if defined(HAVE_INTTYPES_H) || defined(NETBSD)
77 #include <inttypes.h>
78 #endif
79 #include <stdarg.h>
80 #ifndef NETBSD
81 #include <nbcompat/netdb.h>
82 #include <nbcompat/stdio.h>
83 #else
84 #include <netdb.h>
85 #include <stdio.h>
86 #endif
87 #include <stdlib.h>
88 #include <string.h>
89 #include <time.h>
90 #include <unistd.h>
91 
92 #include "fetch.h"
93 #include "common.h"
94 #include "ftperr.h"
95 
96 #define FTP_ANONYMOUS_USER	"anonymous"
97 
98 #define FTP_CONNECTION_ALREADY_OPEN	125
99 #define FTP_OPEN_DATA_CONNECTION	150
100 #define FTP_OK				200
101 #define FTP_FILE_STATUS			213
102 #define FTP_SERVICE_READY		220
103 #define FTP_TRANSFER_COMPLETE		226
104 #define FTP_PASSIVE_MODE		227
105 #define FTP_LPASSIVE_MODE		228
106 #define FTP_EPASSIVE_MODE		229
107 #define FTP_LOGGED_IN			230
108 #define FTP_FILE_ACTION_OK		250
109 #define FTP_DIRECTORY_CREATED		257 /* multiple meanings */
110 #define FTP_FILE_CREATED		257 /* multiple meanings */
111 #define FTP_WORKING_DIRECTORY		257 /* multiple meanings */
112 #define FTP_NEED_PASSWORD		331
113 #define FTP_NEED_ACCOUNT		332
114 #define FTP_FILE_OK			350
115 #define FTP_SYNTAX_ERROR		500
116 #define FTP_PROTOCOL_ERROR		999
117 
118 static struct url cached_host;
119 static conn_t	*cached_connection;
120 
121 #define isftpreply(foo)				\
122 	(isdigit((unsigned char)foo[0]) &&	\
123 	    isdigit((unsigned char)foo[1]) &&	\
124 	    isdigit((unsigned char)foo[2]) &&	\
125 	    (foo[3] == ' ' || foo[3] == '\0'))
126 #define isftpinfo(foo) \
127 	(isdigit((unsigned char)foo[0]) &&	\
128 	    isdigit((unsigned char)foo[1]) &&	\
129 	    isdigit((unsigned char)foo[2]) &&	\
130 	    foo[3] == '-')
131 
132 /*
133  * Translate IPv4 mapped IPv6 address to IPv4 address
134  */
135 static void
136 unmappedaddr(struct sockaddr_in6 *sin6, socklen_t *len)
137 {
138 	struct sockaddr_in *sin4;
139 	uint32_t addr;
140 	int port;
141 
142 	if (sin6->sin6_family != AF_INET6 ||
143 	    !IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
144 		return;
145 	sin4 = (struct sockaddr_in *)sin6;
146 	addr = *(uint32_t *)&sin6->sin6_addr.s6_addr[12];
147 	port = sin6->sin6_port;
148 	memset(sin4, 0, sizeof(struct sockaddr_in));
149 	sin4->sin_addr.s_addr = addr;
150 	sin4->sin_port = port;
151 	sin4->sin_family = AF_INET;
152 	*len = sizeof(struct sockaddr_in);
153 #ifdef HAVE_SA_LEN
154 	sin4->sin_len = sizeof(struct sockaddr_in);
155 #endif
156 }
157 
158 /*
159  * Get server response
160  */
161 static int
162 ftp_chkerr(conn_t *conn)
163 {
164 	if (fetch_getln(conn) == -1) {
165 		fetch_syserr();
166 		return (-1);
167 	}
168 	if (isftpinfo(conn->buf)) {
169 		while (conn->buflen && !isftpreply(conn->buf)) {
170 			if (fetch_getln(conn) == -1) {
171 				fetch_syserr();
172 				return (-1);
173 			}
174 		}
175 	}
176 
177 	while (conn->buflen &&
178 	    isspace((unsigned char)conn->buf[conn->buflen - 1]))
179 		conn->buflen--;
180 	conn->buf[conn->buflen] = '\0';
181 
182 	if (!isftpreply(conn->buf)) {
183 		ftp_seterr(FTP_PROTOCOL_ERROR);
184 		return (-1);
185 	}
186 
187 	conn->err = (conn->buf[0] - '0') * 100
188 	    + (conn->buf[1] - '0') * 10
189 	    + (conn->buf[2] - '0');
190 
191 	return (conn->err);
192 }
193 
194 /*
195  * Send a command and check reply
196  */
197 static int
198 ftp_cmd(conn_t *conn, const char *fmt, ...)
199 {
200 	va_list ap;
201 	size_t len;
202 	char *msg;
203 	int r;
204 
205 	va_start(ap, fmt);
206 	len = vasprintf(&msg, fmt, ap);
207 	va_end(ap);
208 
209 	if (msg == NULL) {
210 		errno = ENOMEM;
211 		fetch_syserr();
212 		return (-1);
213 	}
214 
215 	r = fetch_putln(conn, msg, len);
216 	free(msg);
217 
218 	if (r == -1) {
219 		fetch_syserr();
220 		return (-1);
221 	}
222 
223 	return (ftp_chkerr(conn));
224 }
225 
226 /*
227  * Return a pointer to the filename part of a path
228  */
229 static const char *
230 ftp_filename(const char *file, int *len, int *type, int subdir)
231 {
232 	const char *s;
233 
234 	if ((s = strrchr(file, '/')) == NULL || subdir)
235 		s = file;
236 	else
237 		s = s + 1;
238 	*len = strlen(s);
239 	if (*len > 7 && strncmp(s + *len - 7, ";type=", 6) == 0) {
240 		*type = s[*len - 1];
241 		*len -= 7;
242 	} else {
243 		*type = '\0';
244 	}
245 	return (s);
246 }
247 
248 /*
249  * Get current working directory from the reply to a CWD, PWD or CDUP
250  * command.
251  */
252 static int
253 ftp_pwd(conn_t *conn, char *pwd, size_t pwdlen)
254 {
255 	char *src, *dst, *end;
256 	int q;
257 
258 	if (conn->err != FTP_WORKING_DIRECTORY &&
259 	    conn->err != FTP_FILE_ACTION_OK)
260 		return (FTP_PROTOCOL_ERROR);
261 	end = conn->buf + conn->buflen;
262 	src = conn->buf + 4;
263 	if (src >= end || *src++ != '"')
264 		return (FTP_PROTOCOL_ERROR);
265 	for (q = 0, dst = pwd; src < end && pwdlen--; ++src) {
266 		if (!q && *src == '"')
267 			q = 1;
268 		else if (q && *src != '"')
269 			break;
270 		else if (q)
271 			*dst++ = '"', q = 0;
272 		else
273 			*dst++ = *src;
274 	}
275 	if (!pwdlen)
276 		return (FTP_PROTOCOL_ERROR);
277 	*dst = '\0';
278 	return (FTP_OK);
279 }
280 
281 /*
282  * Change working directory to the directory that contains the specified
283  * file.
284  */
285 static int
286 ftp_cwd(conn_t *conn, const char *file, int subdir)
287 {
288 	const char *beg, *end;
289 	char pwd[PATH_MAX];
290 	int e, i, len;
291 
292 	/* If no slashes in name, no need to change dirs. */
293 	if (subdir)
294 		end = file + strlen(file);
295 	else if ((end = strrchr(file, '/')) == NULL)
296 		return (0);
297 	if ((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 	for (;;) {
303 		len = strlen(pwd);
304 
305 		/* Look for a common prefix between PWD and dir to fetch. */
306 		for (i = 0; i <= len && i <= end - file; ++i)
307 			if (pwd[i] != file[i])
308 				break;
309 		/* Keep going up a dir until we have a matching prefix. */
310 		if (strcmp(pwd, "/") == 0)
311 			break;
312 		if (pwd[i] == '\0' && (file[i - 1] == '/' || file[i] == '/'))
313 			break;
314 		if ((e = ftp_cmd(conn, "CDUP")) != FTP_FILE_ACTION_OK ||
315 		    (e = ftp_cmd(conn, "PWD")) != FTP_WORKING_DIRECTORY ||
316 		    (e = ftp_pwd(conn, pwd, sizeof(pwd))) != FTP_OK) {
317 			ftp_seterr(e);
318 			return (-1);
319 		}
320 	}
321 
322 #ifdef FTP_COMBINE_CWDS
323 	/* Skip leading slashes, even "////". */
324 	for (beg = file + i; beg < end && *beg == '/'; ++beg, ++i)
325 		/* nothing */ ;
326 
327 	/* If there is no trailing dir, we're already there. */
328 	if (beg >= end)
329 		return (0);
330 
331 	/* Change to the directory all in one chunk (e.g., foo/bar/baz). */
332 	e = ftp_cmd(conn, "CWD %.*s", (int)(end - beg), beg);
333 	if (e == FTP_FILE_ACTION_OK)
334 		return (0);
335 #endif /* FTP_COMBINE_CWDS */
336 
337 	/* That didn't work so go back to legacy behavior (multiple CWDs). */
338 	for (beg = file + i; beg < end; beg = file + i + 1) {
339 		while (*beg == '/')
340 			++beg, ++i;
341 		for (++i; file + i < end && file[i] != '/'; ++i)
342 			/* nothing */ ;
343 		e = ftp_cmd(conn, "CWD %.*s", file + i - beg, beg);
344 		if (e != FTP_FILE_ACTION_OK) {
345 			ftp_seterr(e);
346 			return (-1);
347 		}
348 	}
349 	return (0);
350 }
351 
352 /*
353  * Set transfer mode and data type
354  */
355 static int
356 ftp_mode_type(conn_t *conn, int mode, int type)
357 {
358 	int e;
359 
360 	switch (mode) {
361 	case 0:
362 	case 's':
363 		mode = 'S';
364 	case 'S':
365 		break;
366 	default:
367 		return (FTP_PROTOCOL_ERROR);
368 	}
369 	if ((e = ftp_cmd(conn, "MODE %c", mode)) != FTP_OK) {
370 		if (mode == 'S') {
371 			/*
372 			 * Stream mode is supposed to be the default - so
373 			 * much so that some servers not only do not
374 			 * support any other mode, but do not support the
375 			 * MODE command at all.
376 			 *
377 			 * If "MODE S" fails, it is unlikely that we
378 			 * previously succeeded in setting a different
379 			 * mode.  Therefore, we simply hope that the
380 			 * server is already in the correct mode, and
381 			 * silently ignore the failure.
382 			 */
383 		} else {
384 			return (e);
385 		}
386 	}
387 
388 	switch (type) {
389 	case 0:
390 	case 'i':
391 		type = 'I';
392 	case 'I':
393 		break;
394 	case 'a':
395 		type = 'A';
396 	case 'A':
397 		break;
398 	case 'd':
399 		type = 'D';
400 	case 'D':
401 		/* can't handle yet */
402 	default:
403 		return (FTP_PROTOCOL_ERROR);
404 	}
405 	if ((e = ftp_cmd(conn, "TYPE %c", type)) != FTP_OK)
406 		return (e);
407 
408 	return (FTP_OK);
409 }
410 
411 /*
412  * Request and parse file stats
413  */
414 static int
415 ftp_stat(conn_t *conn, const char *file, struct url_stat *us)
416 {
417 	char *ln;
418 	const char *filename;
419 	int filenamelen, type;
420 	struct tm tm;
421 	time_t t;
422 	int e;
423 
424 	us->size = -1;
425 	us->atime = us->mtime = 0;
426 
427 	filename = ftp_filename(file, &filenamelen, &type, 0);
428 
429 	if ((e = ftp_mode_type(conn, 0, type)) != FTP_OK) {
430 		ftp_seterr(e);
431 		return (-1);
432 	}
433 
434 	e = ftp_cmd(conn, "SIZE %.*s", filenamelen, filename);
435 	if (e != FTP_FILE_STATUS) {
436 		ftp_seterr(e);
437 		return (-1);
438 	}
439 	for (ln = conn->buf + 4; *ln && isspace((unsigned char)*ln); ln++)
440 		/* nothing */ ;
441 	for (us->size = 0; *ln && isdigit((unsigned char)*ln); ln++)
442 		us->size = us->size * 10 + *ln - '0';
443 	if (*ln && !isspace((unsigned char)*ln)) {
444 		ftp_seterr(FTP_PROTOCOL_ERROR);
445 		us->size = -1;
446 		return (-1);
447 	}
448 	if (us->size == 0)
449 		us->size = -1;
450 
451 	e = ftp_cmd(conn, "MDTM %.*s", filenamelen, filename);
452 	if (e != FTP_FILE_STATUS) {
453 		ftp_seterr(e);
454 		return (-1);
455 	}
456 	for (ln = conn->buf + 4; *ln && isspace((unsigned char)*ln); ln++)
457 		/* nothing */ ;
458 	switch (strspn(ln, "0123456789")) {
459 	case 14:
460 		break;
461 	case 15:
462 		ln++;
463 		ln[0] = '2';
464 		ln[1] = '0';
465 		break;
466 	default:
467 		ftp_seterr(FTP_PROTOCOL_ERROR);
468 		return (-1);
469 	}
470 	if (sscanf(ln, "%04d%02d%02d%02d%02d%02d",
471 	    &tm.tm_year, &tm.tm_mon, &tm.tm_mday,
472 	    &tm.tm_hour, &tm.tm_min, &tm.tm_sec) != 6) {
473 		ftp_seterr(FTP_PROTOCOL_ERROR);
474 		return (-1);
475 	}
476 	tm.tm_mon--;
477 	tm.tm_year -= 1900;
478 	tm.tm_isdst = -1;
479 	t = timegm(&tm);
480 	if (t == (time_t)-1)
481 		t = time(NULL);
482 	us->mtime = t;
483 	us->atime = t;
484 
485 	return (0);
486 }
487 
488 /*
489  * I/O functions for FTP
490  */
491 struct ftpio {
492 	conn_t	*cconn;		/* Control connection */
493 	conn_t	*dconn;		/* Data connection */
494 	int	 dir;		/* Direction */
495 	int	 eof;		/* EOF reached */
496 	int	 err;		/* Error code */
497 };
498 
499 static ssize_t	 ftp_readfn(void *, void *, size_t);
500 static ssize_t	 ftp_writefn(void *, const void *, size_t);
501 static void	 ftp_closefn(void *);
502 
503 static ssize_t
504 ftp_readfn(void *v, void *buf, size_t len)
505 {
506 	struct ftpio *io;
507 	int r;
508 
509 	io = (struct ftpio *)v;
510 	if (io == NULL) {
511 		errno = EBADF;
512 		return (-1);
513 	}
514 	if (io->cconn == NULL || io->dconn == NULL || io->dir == O_WRONLY) {
515 		errno = EBADF;
516 		return (-1);
517 	}
518 	if (io->err) {
519 		errno = io->err;
520 		return (-1);
521 	}
522 	if (io->eof)
523 		return (0);
524 	r = fetch_read(io->dconn, buf, len);
525 	if (r > 0)
526 		return (r);
527 	if (r == 0) {
528 		io->eof = 1;
529 		return (0);
530 	}
531 	if (errno != EINTR)
532 		io->err = errno;
533 	return (-1);
534 }
535 
536 static ssize_t
537 ftp_writefn(void *v, const void *buf, size_t len)
538 {
539 	struct ftpio *io;
540 	int w;
541 
542 	io = (struct ftpio *)v;
543 	if (io == NULL) {
544 		errno = EBADF;
545 		return (-1);
546 	}
547 	if (io->cconn == NULL || io->dconn == NULL || io->dir == O_RDONLY) {
548 		errno = EBADF;
549 		return (-1);
550 	}
551 	if (io->err) {
552 		errno = io->err;
553 		return (-1);
554 	}
555 	w = fetch_write(io->dconn, buf, len);
556 	if (w >= 0)
557 		return (w);
558 	if (errno != EINTR)
559 		io->err = errno;
560 	return (-1);
561 }
562 
563 static void
564 ftp_closefn(void *v)
565 {
566 	struct ftpio *io;
567 	int r;
568 
569 	io = (struct ftpio *)v;
570 	if (io == NULL) {
571 		errno = EBADF;
572 		return;
573 	}
574 	if (io->dir == -1)
575 		return;
576 	if (io->cconn == NULL || io->dconn == NULL) {
577 		errno = EBADF;
578 		return;
579 	}
580 	fetch_close(io->dconn);
581 	io->dir = -1;
582 	io->dconn = NULL;
583 	r = ftp_chkerr(io->cconn);
584 	if (io->cconn == cached_connection && io->cconn->ref == 1)
585 		cached_connection = NULL;
586 	fetch_close(io->cconn);
587 	free(io);
588 	return;
589 }
590 
591 static fetchIO *
592 ftp_setup(conn_t *cconn, conn_t *dconn, int mode)
593 {
594 	struct ftpio *io;
595 	fetchIO *f;
596 
597 	if (cconn == NULL || dconn == NULL)
598 		return (NULL);
599 	if ((io = malloc(sizeof(*io))) == NULL)
600 		return (NULL);
601 	io->cconn = cconn;
602 	io->dconn = dconn;
603 	io->dir = mode;
604 	io->eof = io->err = 0;
605 	f = fetchIO_unopen(io, ftp_readfn, ftp_writefn, ftp_closefn);
606 	if (f == NULL)
607 		free(io);
608 	return (f);
609 }
610 
611 /*
612  * Transfer file
613  */
614 static fetchIO *
615 ftp_transfer(conn_t *conn, const char *oper, const char *file, const char *op_arg,
616     int mode, off_t offset, const char *flags)
617 {
618 	struct sockaddr_storage sa;
619 	struct sockaddr_in6 *sin6;
620 	struct sockaddr_in *sin4;
621 	const char *bindaddr;
622 	const char *filename;
623 	int filenamelen, type;
624 	int low, pasv, verbose;
625 	int e, sd = -1;
626 	socklen_t l;
627 	char *s;
628 	fetchIO *df;
629 
630 	/* check flags */
631 	low = CHECK_FLAG('l');
632 	pasv = CHECK_FLAG('p');
633 	verbose = CHECK_FLAG('v');
634 
635 	/* passive mode */
636 	if (!pasv)
637 		pasv = ((s = getenv("FTP_PASSIVE_MODE")) != NULL &&
638 		    strncasecmp(s, "no", 2) != 0);
639 
640 	/* isolate filename */
641 	filename = ftp_filename(file, &filenamelen, &type, op_arg != NULL);
642 
643 	/* set transfer mode and data type */
644 	if ((e = ftp_mode_type(conn, 0, type)) != FTP_OK)
645 		goto ouch;
646 
647 	/* find our own address, bind, and listen */
648 	l = sizeof(sa);
649 	if (getsockname(conn->sd, (struct sockaddr *)&sa, &l) == -1)
650 		goto sysouch;
651 	if (sa.ss_family == AF_INET6)
652 		unmappedaddr((struct sockaddr_in6 *)&sa, &l);
653 
654 	/* open data socket */
655 	if ((sd = socket(sa.ss_family, SOCK_STREAM, IPPROTO_TCP)) == -1) {
656 		fetch_syserr();
657 		return (NULL);
658 	}
659 
660 	if (pasv) {
661 		unsigned char addr[64];
662 		char *ln, *p;
663 		unsigned int i;
664 		int port;
665 
666 		/* send PASV command */
667 		if (verbose)
668 			fetch_info("setting passive mode");
669 		switch (sa.ss_family) {
670 		case AF_INET:
671 			if ((e = ftp_cmd(conn, "PASV")) != FTP_PASSIVE_MODE)
672 				goto ouch;
673 			break;
674 		case AF_INET6:
675 			if ((e = ftp_cmd(conn, "EPSV")) != FTP_EPASSIVE_MODE) {
676 				if (e == -1)
677 					goto ouch;
678 				if ((e = ftp_cmd(conn, "LPSV")) !=
679 				    FTP_LPASSIVE_MODE)
680 					goto ouch;
681 			}
682 			break;
683 		default:
684 			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
685 			goto ouch;
686 		}
687 
688 		/*
689 		 * Find address and port number. The reply to the PASV command
690 		 * is IMHO the one and only weak point in the FTP protocol.
691 		 */
692 		ln = conn->buf;
693 		switch (e) {
694 		case FTP_PASSIVE_MODE:
695 		case FTP_LPASSIVE_MODE:
696 			for (p = ln + 3; *p && !isdigit((unsigned char)*p); p++)
697 				/* nothing */ ;
698 			if (!*p) {
699 				e = FTP_PROTOCOL_ERROR;
700 				goto ouch;
701 			}
702 			l = (e == FTP_PASSIVE_MODE ? 6 : 21);
703 			for (i = 0; *p && i < l; i++, p++)
704 				addr[i] = strtol(p, &p, 10);
705 			if (i < l) {
706 				e = FTP_PROTOCOL_ERROR;
707 				goto ouch;
708 			}
709 			break;
710 		case FTP_EPASSIVE_MODE:
711 			for (p = ln + 3; *p && *p != '('; p++)
712 				/* nothing */ ;
713 			if (!*p) {
714 				e = FTP_PROTOCOL_ERROR;
715 				goto ouch;
716 			}
717 			++p;
718 			if (sscanf(p, "%c%c%c%d%c", &addr[0], &addr[1], &addr[2],
719 				&port, &addr[3]) != 5 ||
720 			    addr[0] != addr[1] ||
721 			    addr[0] != addr[2] || addr[0] != addr[3]) {
722 				e = FTP_PROTOCOL_ERROR;
723 				goto ouch;
724 			}
725 			break;
726 		}
727 
728 		/* seek to required offset */
729 		if (offset)
730 			if (ftp_cmd(conn, "REST %lu", (unsigned long)offset) != FTP_FILE_OK)
731 				goto sysouch;
732 
733 		/* construct sockaddr for data socket */
734 		l = sizeof(sa);
735 		if (getpeername(conn->sd, (struct sockaddr *)&sa, &l) == -1)
736 			goto sysouch;
737 		if (sa.ss_family == AF_INET6)
738 			unmappedaddr((struct sockaddr_in6 *)&sa, &l);
739 		switch (sa.ss_family) {
740 		case AF_INET6:
741 			sin6 = (struct sockaddr_in6 *)&sa;
742 			if (e == FTP_EPASSIVE_MODE)
743 				sin6->sin6_port = htons(port);
744 			else {
745 				memcpy(&sin6->sin6_addr, addr + 2, 16);
746 				memcpy(&sin6->sin6_port, addr + 19, 2);
747 			}
748 			break;
749 		case AF_INET:
750 			sin4 = (struct sockaddr_in *)&sa;
751 			if (e == FTP_EPASSIVE_MODE)
752 				sin4->sin_port = htons(port);
753 			else {
754 				memcpy(&sin4->sin_addr, addr, 4);
755 				memcpy(&sin4->sin_port, addr + 4, 2);
756 			}
757 			break;
758 		default:
759 			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
760 			break;
761 		}
762 
763 		/* connect to data port */
764 		if (verbose)
765 			fetch_info("opening data connection");
766 		bindaddr = getenv("FETCH_BIND_ADDRESS");
767 		if (bindaddr != NULL && *bindaddr != '\0' &&
768 		    fetch_bind(sd, sa.ss_family, bindaddr) != 0)
769 			goto sysouch;
770 		if (connect(sd, (struct sockaddr *)&sa, l) == -1)
771 			goto sysouch;
772 
773 		/* make the server initiate the transfer */
774 		if (verbose)
775 			fetch_info("initiating transfer");
776 		if (op_arg)
777 			e = ftp_cmd(conn, "%s%s%s", oper, *op_arg ? " " : "", op_arg);
778 		else
779 			e = ftp_cmd(conn, "%s %.*s", oper,
780 			    filenamelen, filename);
781 		if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
782 			goto ouch;
783 
784 	} else {
785 		uint32_t a;
786 		uint16_t p;
787 #if defined(IPV6_PORTRANGE) || defined(IP_PORTRANGE)
788 		int arg;
789 #endif
790 		int d;
791 		char *ap;
792 		char hname[INET6_ADDRSTRLEN];
793 
794 		switch (sa.ss_family) {
795 		case AF_INET6:
796 			((struct sockaddr_in6 *)&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 *)&arg, sizeof(arg)) == -1)
801 				goto sysouch;
802 #endif
803 			break;
804 		case AF_INET:
805 			((struct sockaddr_in *)&sa)->sin_port = 0;
806 #ifdef IP_PORTRANGE
807 			arg = low ? IP_PORTRANGE_DEFAULT : IP_PORTRANGE_HIGH;
808 			if (setsockopt(sd, IPPROTO_IP, IP_PORTRANGE,
809 				(char *)&arg, sizeof(arg)) == -1)
810 				goto sysouch;
811 #endif
812 			break;
813 		}
814 		if (verbose)
815 			fetch_info("binding data socket");
816 		if (bind(sd, (struct sockaddr *)&sa, l) == -1)
817 			goto sysouch;
818 		if (listen(sd, 1) == -1)
819 			goto sysouch;
820 
821 		/* find what port we're on and tell the server */
822 		if (getsockname(sd, (struct sockaddr *)&sa, &l) == -1)
823 			goto sysouch;
824 		switch (sa.ss_family) {
825 		case AF_INET:
826 			sin4 = (struct sockaddr_in *)&sa;
827 			a = ntohl(sin4->sin_addr.s_addr);
828 			p = ntohs(sin4->sin_port);
829 			e = ftp_cmd(conn, "PORT %d,%d,%d,%d,%d,%d",
830 			    (a >> 24) & 0xff, (a >> 16) & 0xff,
831 			    (a >> 8) & 0xff, a & 0xff,
832 			    (p >> 8) & 0xff, p & 0xff);
833 			break;
834 		case AF_INET6:
835 #define UC(b)	(((int)b)&0xff)
836 			e = -1;
837 			sin6 = (struct sockaddr_in6 *)&sa;
838 			sin6->sin6_scope_id = 0;
839 			if (getnameinfo((struct sockaddr *)&sa, l,
840 				hname, sizeof(hname),
841 				NULL, 0, NI_NUMERICHOST) == 0) {
842 				e = ftp_cmd(conn, "EPRT |%d|%s|%d|", 2, hname,
843 				    htons(sin6->sin6_port));
844 				if (e == -1)
845 					goto ouch;
846 			}
847 			if (e != FTP_OK) {
848 				ap = (char *)&sin6->sin6_addr;
849 				e = ftp_cmd(conn,
850 				    "LPRT %d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d",
851 				    6, 16,
852 				    UC(ap[0]), UC(ap[1]), UC(ap[2]), UC(ap[3]),
853 				    UC(ap[4]), UC(ap[5]), UC(ap[6]), UC(ap[7]),
854 				    UC(ap[8]), UC(ap[9]), UC(ap[10]), UC(ap[11]),
855 				    UC(ap[12]), UC(ap[13]), UC(ap[14]), UC(ap[15]),
856 				    2,
857 				    (ntohs(sin6->sin6_port) >> 8) & 0xff,
858 				    ntohs(sin6->sin6_port)        & 0xff);
859 			}
860 			break;
861 		default:
862 			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
863 			goto ouch;
864 		}
865 		if (e != FTP_OK)
866 			goto ouch;
867 
868 		/* seek to required offset */
869 		if (offset)
870 			if (ftp_cmd(conn, "REST %llu", (unsigned long long)offset) != FTP_FILE_OK)
871 				goto sysouch;
872 
873 		/* make the server initiate the transfer */
874 		if (verbose)
875 			fetch_info("initiating transfer");
876 		if (op_arg)
877 			e = ftp_cmd(conn, "%s%s%s", oper, *op_arg ? " " : "", op_arg);
878 		else
879 			e = ftp_cmd(conn, "%s %.*s", oper,
880 			    filenamelen, filename);
881 		if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
882 			goto ouch;
883 
884 		/* accept the incoming connection and go to town */
885 		if ((d = accept(sd, NULL, NULL)) == -1)
886 			goto sysouch;
887 		close(sd);
888 		sd = d;
889 	}
890 
891 	if ((df = ftp_setup(conn, fetch_reopen(sd), mode)) == NULL)
892 		goto sysouch;
893 	return (df);
894 
895 sysouch:
896 	fetch_syserr();
897 	if (sd >= 0)
898 		close(sd);
899 	return (NULL);
900 
901 ouch:
902 	if (e != -1)
903 		ftp_seterr(e);
904 	if (sd >= 0)
905 		close(sd);
906 	return (NULL);
907 }
908 
909 /*
910  * Authenticate
911  */
912 static int
913 ftp_authenticate(conn_t *conn, struct url *url, struct url *purl)
914 {
915 	const char *user, *pwd, *login_name;
916 	char pbuf[URL_USERLEN + 1 + URL_HOSTLEN + 1];
917 	int e, len;
918 
919 	/* XXX FTP_AUTH, and maybe .netrc */
920 
921 	/* send user name and password */
922 	if (url->user[0] == '\0')
923 		fetch_netrc_auth(url);
924 	user = url->user;
925 	if (*user == '\0')
926 		user = getenv("FTP_LOGIN");
927 	if (user == NULL || *user == '\0')
928 		user = FTP_ANONYMOUS_USER;
929 	if (purl && url->port == fetch_default_port(url->scheme))
930 		e = ftp_cmd(conn, "USER %s@%s", user, url->host);
931 	else if (purl)
932 		e = ftp_cmd(conn, "USER %s@%s@%d", user, url->host, url->port);
933 	else
934 		e = ftp_cmd(conn, "USER %s", user);
935 
936 	/* did the server request a password? */
937 	if (e == FTP_NEED_PASSWORD) {
938 		pwd = url->pwd;
939 		if (*pwd == '\0')
940 			pwd = getenv("FTP_PASSWORD");
941 		if (pwd == NULL || *pwd == '\0') {
942 			if ((login_name = getlogin()) == 0)
943 				login_name = FTP_ANONYMOUS_USER;
944 			if ((len = snprintf(pbuf, URL_USERLEN + 2, "%s@", login_name)) < 0)
945 				len = 0;
946 			else if (len > URL_USERLEN + 1)
947 				len = URL_USERLEN + 1;
948 			gethostname(pbuf + len, sizeof(pbuf) - len);
949 			/* MAXHOSTNAMELEN can differ from URL_HOSTLEN + 1 */
950 			pbuf[sizeof(pbuf) - 1] = '\0';
951 			pwd = pbuf;
952 		}
953 		e = ftp_cmd(conn, "PASS %s", pwd);
954 	}
955 
956 	return (e);
957 }
958 
959 /*
960  * Log on to FTP server
961  */
962 static conn_t *
963 ftp_connect(struct url *url, struct url *purl, const char *flags)
964 {
965 	conn_t *conn;
966 	int e, direct, verbose;
967 #ifdef INET6
968 	int af = AF_UNSPEC;
969 #else
970 	int af = AF_INET;
971 #endif
972 
973 	direct = CHECK_FLAG('d');
974 	verbose = CHECK_FLAG('v');
975 	if (CHECK_FLAG('4'))
976 		af = AF_INET;
977 	else if (CHECK_FLAG('6'))
978 		af = AF_INET6;
979 
980 	if (direct)
981 		purl = NULL;
982 
983 	/* check for proxy */
984 	if (purl) {
985 		/* XXX proxy authentication! */
986 		conn = fetch_connect(purl->host, purl->port, af, verbose);
987 	} else {
988 		/* no proxy, go straight to target */
989 		conn = fetch_connect(url->host, url->port, af, verbose);
990 		purl = NULL;
991 	}
992 
993 	/* check connection */
994 	if (conn == NULL)
995 		/* fetch_connect() has already set an error code */
996 		return (NULL);
997 
998 	/* expect welcome message */
999 	if ((e = ftp_chkerr(conn)) != FTP_SERVICE_READY)
1000 		goto fouch;
1001 
1002 	/* authenticate */
1003 	if ((e = ftp_authenticate(conn, url, purl)) != FTP_LOGGED_IN)
1004 		goto fouch;
1005 
1006 	/* TODO: Request extended features supported, if any (RFC 3659). */
1007 
1008 	/* done */
1009 	return (conn);
1010 
1011 fouch:
1012 	if (e != -1)
1013 		ftp_seterr(e);
1014 	fetch_close(conn);
1015 	return (NULL);
1016 }
1017 
1018 /*
1019  * Disconnect from server
1020  */
1021 static void
1022 ftp_disconnect(conn_t *conn)
1023 {
1024 	(void)ftp_cmd(conn, "QUIT");
1025 	if (conn == cached_connection && conn->ref == 1)
1026 		cached_connection = NULL;
1027 	fetch_close(conn);
1028 }
1029 
1030 /*
1031  * Check if we're already connected
1032  */
1033 static int
1034 ftp_isconnected(struct url *url)
1035 {
1036 	return (cached_connection
1037 	    && (strcmp(url->host, cached_host.host) == 0)
1038 	    && (strcmp(url->user, cached_host.user) == 0)
1039 	    && (strcmp(url->pwd, cached_host.pwd) == 0)
1040 	    && (url->port == cached_host.port));
1041 }
1042 
1043 /*
1044  * Check the cache, reconnect if no luck
1045  */
1046 static conn_t *
1047 ftp_cached_connect(struct url *url, struct url *purl, const char *flags)
1048 {
1049 	conn_t *conn;
1050 	int e;
1051 
1052 	/* set default port */
1053 	if (!url->port)
1054 		url->port = fetch_default_port(url->scheme);
1055 
1056 	/* try to use previously cached connection */
1057 	if (ftp_isconnected(url)) {
1058 		e = ftp_cmd(cached_connection, "NOOP");
1059 		if (e == FTP_OK || e == FTP_SYNTAX_ERROR)
1060 			return (fetch_ref(cached_connection));
1061 	}
1062 
1063 	/* connect to server */
1064 	if ((conn = ftp_connect(url, purl, flags)) == NULL)
1065 		return (NULL);
1066 	if (cached_connection)
1067 		ftp_disconnect(cached_connection);
1068 	cached_connection = fetch_ref(conn);
1069 	memcpy(&cached_host, url, sizeof(*url));
1070 	return (conn);
1071 }
1072 
1073 /*
1074  * Check the proxy settings
1075  */
1076 static struct url *
1077 ftp_get_proxy(struct url * url, const char *flags)
1078 {
1079 	struct url *purl;
1080 	char *p;
1081 
1082 	if (flags != NULL && strchr(flags, 'd') != NULL)
1083 		return (NULL);
1084 	if (fetch_no_proxy_match(url->host))
1085 		return (NULL);
1086 	if (((p = getenv("FTP_PROXY")) || (p = getenv("ftp_proxy")) ||
1087 		(p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
1088 	    *p && (purl = fetchParseURL(p)) != NULL) {
1089 		if (!*purl->scheme) {
1090 			if (getenv("FTP_PROXY") || getenv("ftp_proxy"))
1091 				strcpy(purl->scheme, SCHEME_FTP);
1092 			else
1093 				strcpy(purl->scheme, SCHEME_HTTP);
1094 		}
1095 		if (!purl->port)
1096 			purl->port = fetch_default_proxy_port(purl->scheme);
1097 		if (strcasecmp(purl->scheme, SCHEME_FTP) == 0 ||
1098 		    strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
1099 			return (purl);
1100 		fetchFreeURL(purl);
1101 	}
1102 	return (NULL);
1103 }
1104 
1105 /*
1106  * Process an FTP request
1107  */
1108 fetchIO *
1109 ftp_request(struct url *url, const char *op, const char *op_arg,
1110     struct url_stat *us, struct url *purl, const char *flags)
1111 {
1112 	fetchIO *f;
1113 	char *path;
1114 	conn_t *conn;
1115 	int oflag;
1116 
1117 	/* check if we should use HTTP instead */
1118 	if (purl && strcasecmp(purl->scheme, SCHEME_HTTP) == 0) {
1119 		if (strcmp(op, "STAT") == 0)
1120 			return (http_request(url, "HEAD", us, purl, flags));
1121 		else if (strcmp(op, "RETR") == 0)
1122 			return (http_request(url, "GET", us, purl, flags));
1123 		/*
1124 		 * Our HTTP code doesn't support PUT requests yet, so try
1125 		 * a direct connection.
1126 		 */
1127 	}
1128 
1129 	/* connect to server */
1130 	conn = ftp_cached_connect(url, purl, flags);
1131 	if (purl)
1132 		fetchFreeURL(purl);
1133 	if (conn == NULL)
1134 		return (NULL);
1135 
1136 	if ((path = fetchUnquotePath(url)) == NULL) {
1137 		fetch_syserr();
1138 		return NULL;
1139 	}
1140 
1141 	/* change directory */
1142 	if (ftp_cwd(conn, path, op_arg != NULL) == -1) {
1143 		free(path);
1144 		return (NULL);
1145 	}
1146 
1147 	/* stat file */
1148 	if (us && ftp_stat(conn, path, us) == -1
1149 	    && fetchLastErrCode != FETCH_PROTO
1150 	    && fetchLastErrCode != FETCH_UNAVAIL) {
1151 		free(path);
1152 		return (NULL);
1153 	}
1154 
1155 	/* just a stat */
1156 	if (strcmp(op, "STAT") == 0)
1157 		return fetchIO_unopen(NULL, NULL, NULL, NULL);
1158 	if (strcmp(op, "STOR") == 0 || strcmp(op, "APPE") == 0)
1159 		oflag = O_WRONLY;
1160 	else
1161 		oflag = O_RDONLY;
1162 
1163 	/* initiate the transfer */
1164 	f = (ftp_transfer(conn, op, path, op_arg, oflag, url->offset, flags));
1165 	free(path);
1166 	return f;
1167 }
1168 
1169 /*
1170  * Get and stat file
1171  */
1172 fetchIO *
1173 fetchXGetFTP(struct url *url, struct url_stat *us, const char *flags)
1174 {
1175 	return (ftp_request(url, "RETR", NULL, us, ftp_get_proxy(url, flags), flags));
1176 }
1177 
1178 /*
1179  * Get file
1180  */
1181 fetchIO *
1182 fetchGetFTP(struct url *url, const char *flags)
1183 {
1184 	return (fetchXGetFTP(url, NULL, flags));
1185 }
1186 
1187 /*
1188  * Put file
1189  */
1190 fetchIO *
1191 fetchPutFTP(struct url *url, const char *flags)
1192 {
1193 	return (ftp_request(url, CHECK_FLAG('a') ? "APPE" : "STOR", NULL, NULL,
1194 	    ftp_get_proxy(url, flags), flags));
1195 }
1196 
1197 /*
1198  * Get file stats
1199  */
1200 int
1201 fetchStatFTP(struct url *url, struct url_stat *us, const char *flags)
1202 {
1203 	fetchIO *f;
1204 
1205 	f = ftp_request(url, "STAT", NULL, us, ftp_get_proxy(url, flags), flags);
1206 	if (f == NULL)
1207 		return (-1);
1208 	fetchIO_close(f);
1209 	return (0);
1210 }
1211 
1212 /*
1213  * List a directory
1214  */
1215 int
1216 fetchListFTP(struct url_list *ue, struct url *url, const char *pattern, const char *flags)
1217 {
1218 	fetchIO *f;
1219 	char buf[2 * PATH_MAX], *eol, *eos;
1220 	ssize_t len;
1221 	size_t cur_off;
1222 
1223 	/* XXX What about proxies? */
1224 	if (pattern == NULL || strcmp(pattern, "*") == 0)
1225 		pattern = "";
1226 	f = ftp_request(url, "NLST", pattern, NULL, ftp_get_proxy(url, flags), flags);
1227 	if (f == NULL)
1228 		return -1;
1229 
1230 	cur_off = 0;
1231 	while ((len = fetchIO_read(f, buf + cur_off, sizeof(buf) - cur_off)) > 0) {
1232 		cur_off += len;
1233 		while ((eol = memchr(buf, '\n', cur_off)) != NULL) {
1234 			if (len == eol - buf)
1235 				break;
1236 			if (eol != buf) {
1237 				if (eol[-1] == '\r')
1238 					eos = eol - 1;
1239 				else
1240 					eos = eol;
1241 				*eos = '\0';
1242 				fetch_add_entry(ue, url, buf, 0);
1243 				cur_off -= eol - buf + 1;
1244 				memmove(buf, eol + 1, cur_off);
1245 			}
1246 		}
1247 	}
1248 	if (cur_off != 0 || len < 0) {
1249 		/* Not RFC conform, bail out. */
1250 		fetchIO_close(f);
1251 		return -1;
1252 	}
1253 	fetchIO_close(f);
1254 	return 0;
1255 }
1256