ftp.c revision 174752
1/*-
2 * Copyright (c) 1998-2004 Dag-Erling Co�dan Sm�rgrav
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer
10 *    in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 *    derived from this software without specific prior written permission
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: head/lib/libfetch/ftp.c 174752 2007-12-18 11:03:07Z des $");
31
32/*
33 * Portions of this code were taken from or based on ftpio.c:
34 *
35 * ----------------------------------------------------------------------------
36 * "THE BEER-WARE LICENSE" (Revision 42):
37 * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
38 * can do whatever you want with this stuff. If we meet some day, and you think
39 * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
40 * ----------------------------------------------------------------------------
41 *
42 * Major Changelog:
43 *
44 * Dag-Erling Co�dan Sm�rgrav
45 * 9 Jun 1998
46 *
47 * Incorporated into libfetch
48 *
49 * Jordan K. Hubbard
50 * 17 Jan 1996
51 *
52 * Turned inside out. Now returns xfers as new file ids, not as a special
53 * `state' of FTP_t
54 *
55 * $ftpioId: ftpio.c,v 1.30 1998/04/11 07:28:53 phk Exp $
56 *
57 */
58
59#include <sys/param.h>
60#include <sys/socket.h>
61#include <netinet/in.h>
62
63#include <ctype.h>
64#include <err.h>
65#include <errno.h>
66#include <fcntl.h>
67#include <netdb.h>
68#include <stdarg.h>
69#include <stdint.h>
70#include <stdio.h>
71#include <stdlib.h>
72#include <string.h>
73#include <time.h>
74#include <unistd.h>
75
76#include "fetch.h"
77#include "common.h"
78#include "ftperr.h"
79
80#define FTP_ANONYMOUS_USER	"anonymous"
81
82#define FTP_CONNECTION_ALREADY_OPEN	125
83#define FTP_OPEN_DATA_CONNECTION	150
84#define FTP_OK				200
85#define FTP_FILE_STATUS			213
86#define FTP_SERVICE_READY		220
87#define FTP_TRANSFER_COMPLETE		226
88#define FTP_PASSIVE_MODE		227
89#define FTP_LPASSIVE_MODE		228
90#define FTP_EPASSIVE_MODE		229
91#define FTP_LOGGED_IN			230
92#define FTP_FILE_ACTION_OK		250
93#define FTP_DIRECTORY_CREATED		257 /* multiple meanings */
94#define FTP_FILE_CREATED		257 /* multiple meanings */
95#define FTP_WORKING_DIRECTORY		257 /* multiple meanings */
96#define FTP_NEED_PASSWORD		331
97#define FTP_NEED_ACCOUNT		332
98#define FTP_FILE_OK			350
99#define FTP_SYNTAX_ERROR		500
100#define FTP_PROTOCOL_ERROR		999
101
102static struct url cached_host;
103static conn_t	*cached_connection;
104
105#define isftpreply(foo) (isdigit((int)foo[0]) && isdigit((int)foo[1]) \
106			 && isdigit((int)foo[2]) \
107			 && (foo[3] == ' ' || foo[3] == '\0'))
108#define isftpinfo(foo) (isdigit((int)foo[0]) && isdigit((int)foo[1]) \
109			&& isdigit((int)foo[2]) && foo[3] == '-')
110
111/*
112 * Translate IPv4 mapped IPv6 address to IPv4 address
113 */
114static void
115unmappedaddr(struct sockaddr_in6 *sin6)
116{
117	struct sockaddr_in *sin4;
118	u_int32_t addr;
119	int port;
120
121	if (sin6->sin6_family != AF_INET6 ||
122	    !IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
123		return;
124	sin4 = (struct sockaddr_in *)sin6;
125	addr = *(u_int32_t *)&sin6->sin6_addr.s6_addr[12];
126	port = sin6->sin6_port;
127	memset(sin4, 0, sizeof(struct sockaddr_in));
128	sin4->sin_addr.s_addr = addr;
129	sin4->sin_port = port;
130	sin4->sin_family = AF_INET;
131	sin4->sin_len = sizeof(struct sockaddr_in);
132}
133
134/*
135 * Get server response
136 */
137static int
138ftp_chkerr(conn_t *conn)
139{
140	if (fetch_getln(conn) == -1) {
141		fetch_syserr();
142		return (-1);
143	}
144	if (isftpinfo(conn->buf)) {
145		while (conn->buflen && !isftpreply(conn->buf)) {
146			if (fetch_getln(conn) == -1) {
147				fetch_syserr();
148				return (-1);
149			}
150		}
151	}
152
153	while (conn->buflen && isspace((int)conn->buf[conn->buflen - 1]))
154		conn->buflen--;
155	conn->buf[conn->buflen] = '\0';
156
157	if (!isftpreply(conn->buf)) {
158		ftp_seterr(FTP_PROTOCOL_ERROR);
159		return (-1);
160	}
161
162	conn->err = (conn->buf[0] - '0') * 100
163	    + (conn->buf[1] - '0') * 10
164	    + (conn->buf[2] - '0');
165
166	return (conn->err);
167}
168
169/*
170 * Send a command and check reply
171 */
172static int
173ftp_cmd(conn_t *conn, const char *fmt, ...)
174{
175	va_list ap;
176	size_t len;
177	char *msg;
178	int r;
179
180	va_start(ap, fmt);
181	len = vasprintf(&msg, fmt, ap);
182	va_end(ap);
183
184	if (msg == NULL) {
185		errno = ENOMEM;
186		fetch_syserr();
187		return (-1);
188	}
189
190	r = fetch_putln(conn, msg, len);
191	free(msg);
192
193	if (r == -1) {
194		fetch_syserr();
195		return (-1);
196	}
197
198	return (ftp_chkerr(conn));
199}
200
201/*
202 * Return a pointer to the filename part of a path
203 */
204static const char *
205ftp_filename(const char *file, int *len, int *type)
206{
207	const char *s;
208
209	if ((s = strrchr(file, '/')) == NULL)
210		s = file;
211	else
212		s = s + 1;
213	*len = strlen(s);
214	if (*len > 7 && strncmp(s + *len - 7, ";type=", 6) == 0) {
215		*type = s[*len - 1];
216		*len -= 7;
217	} else {
218		*type = '\0';
219	}
220	return (s);
221}
222
223/*
224 * Get current working directory from the reply to a CWD, PWD or CDUP
225 * command.
226 */
227static int
228ftp_pwd(conn_t *conn, char *pwd, size_t pwdlen)
229{
230	char *src, *dst, *end;
231	int q;
232
233	if (conn->err != FTP_WORKING_DIRECTORY &&
234	    conn->err != FTP_FILE_ACTION_OK)
235		return (FTP_PROTOCOL_ERROR);
236	end = conn->buf + conn->buflen;
237	src = conn->buf + 4;
238	if (src >= end || *src++ != '"')
239		return (FTP_PROTOCOL_ERROR);
240	for (q = 0, dst = pwd; src < end && pwdlen--; ++src) {
241		if (!q && *src == '"')
242			q = 1;
243		else if (q && *src != '"')
244			break;
245		else if (q)
246			*dst++ = '"', q = 0;
247		else
248			*dst++ = *src;
249	}
250	if (!pwdlen)
251		return (FTP_PROTOCOL_ERROR);
252	*dst = '\0';
253#if 0
254	DEBUG(fprintf(stderr, "pwd: [%s]\n", pwd));
255#endif
256	return (FTP_OK);
257}
258
259/*
260 * Change working directory to the directory that contains the specified
261 * file.
262 */
263static int
264ftp_cwd(conn_t *conn, const char *file)
265{
266	const char *beg, *end;
267	char pwd[PATH_MAX];
268	int e, i, len;
269
270	/* If no slashes in name, no need to change dirs. */
271	if ((end = strrchr(file, '/')) == NULL)
272		return (0);
273	if ((e = ftp_cmd(conn, "PWD")) != FTP_WORKING_DIRECTORY ||
274	    (e = ftp_pwd(conn, pwd, sizeof(pwd))) != FTP_OK) {
275		ftp_seterr(e);
276		return (-1);
277	}
278	for (;;) {
279		len = strlen(pwd);
280
281		/* Look for a common prefix between PWD and dir to fetch. */
282		for (i = 0; i <= len && i <= end - file; ++i)
283			if (pwd[i] != file[i])
284				break;
285#if 0
286		DEBUG(fprintf(stderr, "have: [%.*s|%s]\n", i, pwd, pwd + i));
287		DEBUG(fprintf(stderr, "want: [%.*s|%s]\n", i, file, file + i));
288#endif
289		/* Keep going up a dir until we have a matching prefix. */
290		if (pwd[i] == '\0' && (file[i - 1] == '/' || file[i] == '/'))
291			break;
292		if ((e = ftp_cmd(conn, "CDUP")) != FTP_FILE_ACTION_OK ||
293		    (e = ftp_cmd(conn, "PWD")) != FTP_WORKING_DIRECTORY ||
294		    (e = ftp_pwd(conn, pwd, sizeof(pwd))) != FTP_OK) {
295			ftp_seterr(e);
296			return (-1);
297		}
298	}
299
300#ifdef FTP_COMBINE_CWDS
301	/* Skip leading slashes, even "////". */
302	for (beg = file + i; beg < end && *beg == '/'; ++beg, ++i)
303		/* nothing */ ;
304
305	/* If there is no trailing dir, we're already there. */
306	if (beg >= end)
307		return (0);
308
309	/* Change to the directory all in one chunk (e.g., foo/bar/baz). */
310	e = ftp_cmd(conn, "CWD %.*s", (int)(end - beg), beg);
311	if (e == FTP_FILE_ACTION_OK)
312		return (0);
313#endif /* FTP_COMBINE_CWDS */
314
315	/* That didn't work so go back to legacy behavior (multiple CWDs). */
316	for (beg = file + i; beg < end; beg = file + i + 1) {
317		while (*beg == '/')
318			++beg, ++i;
319		for (++i; file + i < end && file[i] != '/'; ++i)
320			/* nothing */ ;
321		e = ftp_cmd(conn, "CWD %.*s", file + i - beg, beg);
322		if (e != FTP_FILE_ACTION_OK) {
323			ftp_seterr(e);
324			return (-1);
325		}
326	}
327	return (0);
328}
329
330/*
331 * Set transfer mode and data type
332 */
333static int
334ftp_mode_type(conn_t *conn, int mode, int type)
335{
336	int e;
337
338	switch (mode) {
339	case 0:
340	case 's':
341		mode = 'S';
342	case 'S':
343		break;
344	default:
345		return (FTP_PROTOCOL_ERROR);
346	}
347	if ((e = ftp_cmd(conn, "MODE %c", mode)) != FTP_OK) {
348		if (mode == 'S') {
349			/*
350			 * Stream mode is supposed to be the default - so
351			 * much so that some servers not only do not
352			 * support any other mode, but do not support the
353			 * MODE command at all.
354			 *
355			 * If "MODE S" fails, it is unlikely that we
356			 * previously succeeded in setting a different
357			 * mode.  Therefore, we simply hope that the
358			 * server is already in the correct mode, and
359			 * silently ignore the failure.
360			 */
361		} else {
362			return (e);
363		}
364	}
365
366	switch (type) {
367	case 0:
368	case 'i':
369		type = 'I';
370	case 'I':
371		break;
372	case 'a':
373		type = 'A';
374	case 'A':
375		break;
376	case 'd':
377		type = 'D';
378	case 'D':
379		/* can't handle yet */
380	default:
381		return (FTP_PROTOCOL_ERROR);
382	}
383	if ((e = ftp_cmd(conn, "TYPE %c", type)) != FTP_OK)
384		return (e);
385
386	return (FTP_OK);
387}
388
389/*
390 * Request and parse file stats
391 */
392static int
393ftp_stat(conn_t *conn, const char *file, struct url_stat *us)
394{
395	char *ln;
396	const char *filename;
397	int filenamelen, type;
398	struct tm tm;
399	time_t t;
400	int e;
401
402	us->size = -1;
403	us->atime = us->mtime = 0;
404
405	filename = ftp_filename(file, &filenamelen, &type);
406
407	if ((e = ftp_mode_type(conn, 0, type)) != FTP_OK) {
408		ftp_seterr(e);
409		return (-1);
410	}
411
412	e = ftp_cmd(conn, "SIZE %.*s", filenamelen, filename);
413	if (e != FTP_FILE_STATUS) {
414		ftp_seterr(e);
415		return (-1);
416	}
417	for (ln = conn->buf + 4; *ln && isspace((int)*ln); ln++)
418		/* nothing */ ;
419	for (us->size = 0; *ln && isdigit((int)*ln); ln++)
420		us->size = us->size * 10 + *ln - '0';
421	if (*ln && !isspace((int)*ln)) {
422		ftp_seterr(FTP_PROTOCOL_ERROR);
423		us->size = -1;
424		return (-1);
425	}
426	if (us->size == 0)
427		us->size = -1;
428	DEBUG(fprintf(stderr, "size: [%lld]\n", (long long)us->size));
429
430	e = ftp_cmd(conn, "MDTM %.*s", filenamelen, filename);
431	if (e != FTP_FILE_STATUS) {
432		ftp_seterr(e);
433		return (-1);
434	}
435	for (ln = conn->buf + 4; *ln && isspace((int)*ln); ln++)
436		/* nothing */ ;
437	switch (strspn(ln, "0123456789")) {
438	case 14:
439		break;
440	case 15:
441		ln++;
442		ln[0] = '2';
443		ln[1] = '0';
444		break;
445	default:
446		ftp_seterr(FTP_PROTOCOL_ERROR);
447		return (-1);
448	}
449	if (sscanf(ln, "%04d%02d%02d%02d%02d%02d",
450	    &tm.tm_year, &tm.tm_mon, &tm.tm_mday,
451	    &tm.tm_hour, &tm.tm_min, &tm.tm_sec) != 6) {
452		ftp_seterr(FTP_PROTOCOL_ERROR);
453		return (-1);
454	}
455	tm.tm_mon--;
456	tm.tm_year -= 1900;
457	tm.tm_isdst = -1;
458	t = timegm(&tm);
459	if (t == (time_t)-1)
460		t = time(NULL);
461	us->mtime = t;
462	us->atime = t;
463	DEBUG(fprintf(stderr,
464	    "last modified: [%04d-%02d-%02d %02d:%02d:%02d]\n",
465	    tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
466	    tm.tm_hour, tm.tm_min, tm.tm_sec));
467	return (0);
468}
469
470/*
471 * I/O functions for FTP
472 */
473struct ftpio {
474	conn_t	*cconn;		/* Control connection */
475	conn_t	*dconn;		/* Data connection */
476	int	 dir;		/* Direction */
477	int	 eof;		/* EOF reached */
478	int	 err;		/* Error code */
479};
480
481static int	 ftp_readfn(void *, char *, int);
482static int	 ftp_writefn(void *, const char *, int);
483static fpos_t	 ftp_seekfn(void *, fpos_t, int);
484static int	 ftp_closefn(void *);
485
486static int
487ftp_readfn(void *v, char *buf, int len)
488{
489	struct ftpio *io;
490	int r;
491
492	io = (struct ftpio *)v;
493	if (io == NULL) {
494		errno = EBADF;
495		return (-1);
496	}
497	if (io->cconn == NULL || io->dconn == NULL || io->dir == O_WRONLY) {
498		errno = EBADF;
499		return (-1);
500	}
501	if (io->err) {
502		errno = io->err;
503		return (-1);
504	}
505	if (io->eof)
506		return (0);
507	r = fetch_read(io->dconn, buf, len);
508	if (r > 0)
509		return (r);
510	if (r == 0) {
511		io->eof = 1;
512		return (0);
513	}
514	if (errno != EINTR)
515		io->err = errno;
516	return (-1);
517}
518
519static int
520ftp_writefn(void *v, const char *buf, int len)
521{
522	struct ftpio *io;
523	int w;
524
525	io = (struct ftpio *)v;
526	if (io == NULL) {
527		errno = EBADF;
528		return (-1);
529	}
530	if (io->cconn == NULL || io->dconn == NULL || io->dir == O_RDONLY) {
531		errno = EBADF;
532		return (-1);
533	}
534	if (io->err) {
535		errno = io->err;
536		return (-1);
537	}
538	w = fetch_write(io->dconn, buf, len);
539	if (w >= 0)
540		return (w);
541	if (errno != EINTR)
542		io->err = errno;
543	return (-1);
544}
545
546static fpos_t
547ftp_seekfn(void *v, fpos_t pos __unused, int whence __unused)
548{
549	struct ftpio *io;
550
551	io = (struct ftpio *)v;
552	if (io == NULL) {
553		errno = EBADF;
554		return (-1);
555	}
556	errno = ESPIPE;
557	return (-1);
558}
559
560static int
561ftp_closefn(void *v)
562{
563	struct ftpio *io;
564	int r;
565
566	io = (struct ftpio *)v;
567	if (io == NULL) {
568		errno = EBADF;
569		return (-1);
570	}
571	if (io->dir == -1)
572		return (0);
573	if (io->cconn == NULL || io->dconn == NULL) {
574		errno = EBADF;
575		return (-1);
576	}
577	fetch_close(io->dconn);
578	io->dir = -1;
579	io->dconn = NULL;
580	DEBUG(fprintf(stderr, "Waiting for final status\n"));
581	r = ftp_chkerr(io->cconn);
582	if (io->cconn == cached_connection && io->cconn->ref == 1)
583		cached_connection = NULL;
584	fetch_close(io->cconn);
585	free(io);
586	return (r == FTP_TRANSFER_COMPLETE) ? 0 : -1;
587}
588
589static FILE *
590ftp_setup(conn_t *cconn, conn_t *dconn, int mode)
591{
592	struct ftpio *io;
593	FILE *f;
594
595	if (cconn == NULL || dconn == NULL)
596		return (NULL);
597	if ((io = malloc(sizeof(*io))) == NULL)
598		return (NULL);
599	io->cconn = cconn;
600	io->dconn = dconn;
601	io->dir = mode;
602	io->eof = io->err = 0;
603	f = funopen(io, ftp_readfn, ftp_writefn, ftp_seekfn, ftp_closefn);
604	if (f == NULL)
605		free(io);
606	return (f);
607}
608
609/*
610 * Transfer file
611 */
612static FILE *
613ftp_transfer(conn_t *conn, const char *oper, const char *file,
614    int mode, off_t offset, const char *flags)
615{
616	struct sockaddr_storage sa;
617	struct sockaddr_in6 *sin6;
618	struct sockaddr_in *sin4;
619	const char *bindaddr;
620	const char *filename;
621	int filenamelen, type;
622	int low, pasv, verbose;
623	int e, sd = -1;
624	socklen_t l;
625	char *s;
626	FILE *df;
627
628	/* check flags */
629	low = CHECK_FLAG('l');
630	pasv = CHECK_FLAG('p');
631	verbose = CHECK_FLAG('v');
632
633	/* passive mode */
634	if (!pasv)
635		pasv = ((s = getenv("FTP_PASSIVE_MODE")) != NULL &&
636		    strncasecmp(s, "no", 2) != 0);
637
638	/* isolate filename */
639	filename = ftp_filename(file, &filenamelen, &type);
640
641	/* set transfer mode and data type */
642	if ((e = ftp_mode_type(conn, 0, type)) != FTP_OK)
643		goto ouch;
644
645	/* find our own address, bind, and listen */
646	l = sizeof(sa);
647	if (getsockname(conn->sd, (struct sockaddr *)&sa, &l) == -1)
648		goto sysouch;
649	if (sa.ss_family == AF_INET6)
650		unmappedaddr((struct sockaddr_in6 *)&sa);
651
652	/* open data socket */
653	if ((sd = socket(sa.ss_family, SOCK_STREAM, IPPROTO_TCP)) == -1) {
654		fetch_syserr();
655		return (NULL);
656	}
657
658	if (pasv) {
659		u_char addr[64];
660		char *ln, *p;
661		unsigned int i;
662		int port;
663
664		/* send PASV command */
665		if (verbose)
666			fetch_info("setting passive mode");
667		switch (sa.ss_family) {
668		case AF_INET:
669			if ((e = ftp_cmd(conn, "PASV")) != FTP_PASSIVE_MODE)
670				goto ouch;
671			break;
672		case AF_INET6:
673			if ((e = ftp_cmd(conn, "EPSV")) != FTP_EPASSIVE_MODE) {
674				if (e == -1)
675					goto ouch;
676				if ((e = ftp_cmd(conn, "LPSV")) !=
677				    FTP_LPASSIVE_MODE)
678					goto ouch;
679			}
680			break;
681		default:
682			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
683			goto ouch;
684		}
685
686		/*
687		 * Find address and port number. The reply to the PASV command
688		 * is IMHO the one and only weak point in the FTP protocol.
689		 */
690		ln = conn->buf;
691		switch (e) {
692		case FTP_PASSIVE_MODE:
693		case FTP_LPASSIVE_MODE:
694			for (p = ln + 3; *p && !isdigit((int)*p); p++)
695				/* nothing */ ;
696			if (!*p) {
697				e = FTP_PROTOCOL_ERROR;
698				goto ouch;
699			}
700			l = (e == FTP_PASSIVE_MODE ? 6 : 21);
701			for (i = 0; *p && i < l; i++, p++)
702				addr[i] = strtol(p, &p, 10);
703			if (i < l) {
704				e = FTP_PROTOCOL_ERROR;
705				goto ouch;
706			}
707			break;
708		case FTP_EPASSIVE_MODE:
709			for (p = ln + 3; *p && *p != '('; p++)
710				/* nothing */ ;
711			if (!*p) {
712				e = FTP_PROTOCOL_ERROR;
713				goto ouch;
714			}
715			++p;
716			if (sscanf(p, "%c%c%c%d%c", &addr[0], &addr[1], &addr[2],
717				&port, &addr[3]) != 5 ||
718			    addr[0] != addr[1] ||
719			    addr[0] != addr[2] || addr[0] != addr[3]) {
720				e = FTP_PROTOCOL_ERROR;
721				goto ouch;
722			}
723			break;
724		}
725
726		/* seek to required offset */
727		if (offset)
728			if (ftp_cmd(conn, "REST %lu", (u_long)offset) != FTP_FILE_OK)
729				goto sysouch;
730
731		/* construct sockaddr for data socket */
732		l = sizeof(sa);
733		if (getpeername(conn->sd, (struct sockaddr *)&sa, &l) == -1)
734			goto sysouch;
735		if (sa.ss_family == AF_INET6)
736			unmappedaddr((struct sockaddr_in6 *)&sa);
737		switch (sa.ss_family) {
738		case AF_INET6:
739			sin6 = (struct sockaddr_in6 *)&sa;
740			if (e == FTP_EPASSIVE_MODE)
741				sin6->sin6_port = htons(port);
742			else {
743				bcopy(addr + 2, (char *)&sin6->sin6_addr, 16);
744				bcopy(addr + 19, (char *)&sin6->sin6_port, 2);
745			}
746			break;
747		case AF_INET:
748			sin4 = (struct sockaddr_in *)&sa;
749			if (e == FTP_EPASSIVE_MODE)
750				sin4->sin_port = htons(port);
751			else {
752				bcopy(addr, (char *)&sin4->sin_addr, 4);
753				bcopy(addr + 4, (char *)&sin4->sin_port, 2);
754			}
755			break;
756		default:
757			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
758			break;
759		}
760
761		/* connect to data port */
762		if (verbose)
763			fetch_info("opening data connection");
764		bindaddr = getenv("FETCH_BIND_ADDRESS");
765		if (bindaddr != NULL && *bindaddr != '\0' &&
766		    fetch_bind(sd, sa.ss_family, bindaddr) != 0)
767			goto sysouch;
768		if (connect(sd, (struct sockaddr *)&sa, sa.ss_len) == -1)
769			goto sysouch;
770
771		/* make the server initiate the transfer */
772		if (verbose)
773			fetch_info("initiating transfer");
774		e = ftp_cmd(conn, "%s %.*s", oper, filenamelen, filename);
775		if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
776			goto ouch;
777
778	} else {
779		u_int32_t a;
780		u_short p;
781		int arg, d;
782		char *ap;
783		char hname[INET6_ADDRSTRLEN];
784
785		switch (sa.ss_family) {
786		case AF_INET6:
787			((struct sockaddr_in6 *)&sa)->sin6_port = 0;
788#ifdef IPV6_PORTRANGE
789			arg = low ? IPV6_PORTRANGE_DEFAULT : IPV6_PORTRANGE_HIGH;
790			if (setsockopt(sd, IPPROTO_IPV6, IPV6_PORTRANGE,
791				(char *)&arg, sizeof(arg)) == -1)
792				goto sysouch;
793#endif
794			break;
795		case AF_INET:
796			((struct sockaddr_in *)&sa)->sin_port = 0;
797			arg = low ? IP_PORTRANGE_DEFAULT : IP_PORTRANGE_HIGH;
798			if (setsockopt(sd, IPPROTO_IP, IP_PORTRANGE,
799				(char *)&arg, sizeof(arg)) == -1)
800				goto sysouch;
801			break;
802		}
803		if (verbose)
804			fetch_info("binding data socket");
805		if (bind(sd, (struct sockaddr *)&sa, sa.ss_len) == -1)
806			goto sysouch;
807		if (listen(sd, 1) == -1)
808			goto sysouch;
809
810		/* find what port we're on and tell the server */
811		if (getsockname(sd, (struct sockaddr *)&sa, &l) == -1)
812			goto sysouch;
813		switch (sa.ss_family) {
814		case AF_INET:
815			sin4 = (struct sockaddr_in *)&sa;
816			a = ntohl(sin4->sin_addr.s_addr);
817			p = ntohs(sin4->sin_port);
818			e = ftp_cmd(conn, "PORT %d,%d,%d,%d,%d,%d",
819			    (a >> 24) & 0xff, (a >> 16) & 0xff,
820			    (a >> 8) & 0xff, a & 0xff,
821			    (p >> 8) & 0xff, p & 0xff);
822			break;
823		case AF_INET6:
824#define UC(b)	(((int)b)&0xff)
825			e = -1;
826			sin6 = (struct sockaddr_in6 *)&sa;
827			sin6->sin6_scope_id = 0;
828			if (getnameinfo((struct sockaddr *)&sa, sa.ss_len,
829				hname, sizeof(hname),
830				NULL, 0, NI_NUMERICHOST) == 0) {
831				e = ftp_cmd(conn, "EPRT |%d|%s|%d|", 2, hname,
832				    htons(sin6->sin6_port));
833				if (e == -1)
834					goto ouch;
835			}
836			if (e != FTP_OK) {
837				ap = (char *)&sin6->sin6_addr;
838				e = ftp_cmd(conn,
839				    "LPRT %d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d",
840				    6, 16,
841				    UC(ap[0]), UC(ap[1]), UC(ap[2]), UC(ap[3]),
842				    UC(ap[4]), UC(ap[5]), UC(ap[6]), UC(ap[7]),
843				    UC(ap[8]), UC(ap[9]), UC(ap[10]), UC(ap[11]),
844				    UC(ap[12]), UC(ap[13]), UC(ap[14]), UC(ap[15]),
845				    2,
846				    (ntohs(sin6->sin6_port) >> 8) & 0xff,
847				    ntohs(sin6->sin6_port)        & 0xff);
848			}
849			break;
850		default:
851			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
852			goto ouch;
853		}
854		if (e != FTP_OK)
855			goto ouch;
856
857		/* seek to required offset */
858		if (offset)
859			if (ftp_cmd(conn, "REST %ju", (uintmax_t)offset) != FTP_FILE_OK)
860				goto sysouch;
861
862		/* make the server initiate the transfer */
863		if (verbose)
864			fetch_info("initiating transfer");
865		e = ftp_cmd(conn, "%s %.*s", oper, filenamelen, filename);
866		if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
867			goto ouch;
868
869		/* accept the incoming connection and go to town */
870		if ((d = accept(sd, NULL, NULL)) == -1)
871			goto sysouch;
872		close(sd);
873		sd = d;
874	}
875
876	if ((df = ftp_setup(conn, fetch_reopen(sd), mode)) == NULL)
877		goto sysouch;
878	return (df);
879
880sysouch:
881	fetch_syserr();
882	if (sd >= 0)
883		close(sd);
884	return (NULL);
885
886ouch:
887	if (e != -1)
888		ftp_seterr(e);
889	if (sd >= 0)
890		close(sd);
891	return (NULL);
892}
893
894/*
895 * Authenticate
896 */
897static int
898ftp_authenticate(conn_t *conn, struct url *url, struct url *purl)
899{
900	const char *user, *pwd, *logname;
901	char pbuf[MAXHOSTNAMELEN + MAXLOGNAME + 1];
902	int e, len;
903
904	/* XXX FTP_AUTH, and maybe .netrc */
905
906	/* send user name and password */
907	if (url->user[0] == '\0')
908		fetch_netrc_auth(url);
909	user = url->user;
910	if (*user == '\0')
911		user = getenv("FTP_LOGIN");
912	if (user == NULL || *user == '\0')
913		user = FTP_ANONYMOUS_USER;
914	if (purl && url->port == fetch_default_port(url->scheme))
915		e = ftp_cmd(conn, "USER %s@%s", user, url->host);
916	else if (purl)
917		e = ftp_cmd(conn, "USER %s@%s@%d", user, url->host, url->port);
918	else
919		e = ftp_cmd(conn, "USER %s", user);
920
921	/* did the server request a password? */
922	if (e == FTP_NEED_PASSWORD) {
923		pwd = url->pwd;
924		if (*pwd == '\0')
925			pwd = getenv("FTP_PASSWORD");
926		if (pwd == NULL || *pwd == '\0') {
927			if ((logname = getlogin()) == 0)
928				logname = FTP_ANONYMOUS_USER;
929			if ((len = snprintf(pbuf, MAXLOGNAME + 1, "%s@", logname)) < 0)
930				len = 0;
931			else if (len > MAXLOGNAME)
932				len = MAXLOGNAME;
933			gethostname(pbuf + len, sizeof(pbuf) - len);
934			pwd = pbuf;
935		}
936		e = ftp_cmd(conn, "PASS %s", pwd);
937	}
938
939	return (e);
940}
941
942/*
943 * Log on to FTP server
944 */
945static conn_t *
946ftp_connect(struct url *url, struct url *purl, const char *flags)
947{
948	conn_t *conn;
949	int e, direct, verbose;
950#ifdef INET6
951	int af = AF_UNSPEC;
952#else
953	int af = AF_INET;
954#endif
955
956	direct = CHECK_FLAG('d');
957	verbose = CHECK_FLAG('v');
958	if (CHECK_FLAG('4'))
959		af = AF_INET;
960	else if (CHECK_FLAG('6'))
961		af = AF_INET6;
962
963	if (direct)
964		purl = NULL;
965
966	/* check for proxy */
967	if (purl) {
968		/* XXX proxy authentication! */
969		conn = fetch_connect(purl->host, purl->port, af, verbose);
970	} else {
971		/* no proxy, go straight to target */
972		conn = fetch_connect(url->host, url->port, af, verbose);
973		purl = NULL;
974	}
975
976	/* check connection */
977	if (conn == NULL)
978		/* fetch_connect() has already set an error code */
979		return (NULL);
980
981	/* expect welcome message */
982	if ((e = ftp_chkerr(conn)) != FTP_SERVICE_READY)
983		goto fouch;
984
985	/* authenticate */
986	if ((e = ftp_authenticate(conn, url, purl)) != FTP_LOGGED_IN)
987		goto fouch;
988
989	/* TODO: Request extended features supported, if any (RFC 3659). */
990
991	/* done */
992	return (conn);
993
994fouch:
995	if (e != -1)
996		ftp_seterr(e);
997	fetch_close(conn);
998	return (NULL);
999}
1000
1001/*
1002 * Disconnect from server
1003 */
1004static void
1005ftp_disconnect(conn_t *conn)
1006{
1007	(void)ftp_cmd(conn, "QUIT");
1008	if (conn == cached_connection && conn->ref == 1)
1009		cached_connection = NULL;
1010	fetch_close(conn);
1011}
1012
1013/*
1014 * Check if we're already connected
1015 */
1016static int
1017ftp_isconnected(struct url *url)
1018{
1019	return (cached_connection
1020	    && (strcmp(url->host, cached_host.host) == 0)
1021	    && (strcmp(url->user, cached_host.user) == 0)
1022	    && (strcmp(url->pwd, cached_host.pwd) == 0)
1023	    && (url->port == cached_host.port));
1024}
1025
1026/*
1027 * Check the cache, reconnect if no luck
1028 */
1029static conn_t *
1030ftp_cached_connect(struct url *url, struct url *purl, const char *flags)
1031{
1032	conn_t *conn;
1033	int e;
1034
1035	/* set default port */
1036	if (!url->port)
1037		url->port = fetch_default_port(url->scheme);
1038
1039	/* try to use previously cached connection */
1040	if (ftp_isconnected(url)) {
1041		e = ftp_cmd(cached_connection, "NOOP");
1042		if (e == FTP_OK || e == FTP_SYNTAX_ERROR)
1043			return (fetch_ref(cached_connection));
1044	}
1045
1046	/* connect to server */
1047	if ((conn = ftp_connect(url, purl, flags)) == NULL)
1048		return (NULL);
1049	if (cached_connection)
1050		ftp_disconnect(cached_connection);
1051	cached_connection = fetch_ref(conn);
1052	memcpy(&cached_host, url, sizeof(*url));
1053	return (conn);
1054}
1055
1056/*
1057 * Check the proxy settings
1058 */
1059static struct url *
1060ftp_get_proxy(struct url * url, const char *flags)
1061{
1062	struct url *purl;
1063	char *p;
1064
1065	if (flags != NULL && strchr(flags, 'd') != NULL)
1066		return (NULL);
1067	if (fetch_no_proxy_match(url->host))
1068		return (NULL);
1069	if (((p = getenv("FTP_PROXY")) || (p = getenv("ftp_proxy")) ||
1070		(p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
1071	    *p && (purl = fetchParseURL(p)) != NULL) {
1072		if (!*purl->scheme) {
1073			if (getenv("FTP_PROXY") || getenv("ftp_proxy"))
1074				strcpy(purl->scheme, SCHEME_FTP);
1075			else
1076				strcpy(purl->scheme, SCHEME_HTTP);
1077		}
1078		if (!purl->port)
1079			purl->port = fetch_default_proxy_port(purl->scheme);
1080		if (strcasecmp(purl->scheme, SCHEME_FTP) == 0 ||
1081		    strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
1082			return (purl);
1083		fetchFreeURL(purl);
1084	}
1085	return (NULL);
1086}
1087
1088/*
1089 * Process an FTP request
1090 */
1091FILE *
1092ftp_request(struct url *url, const char *op, struct url_stat *us,
1093    struct url *purl, const char *flags)
1094{
1095	conn_t *conn;
1096	int oflag;
1097
1098	/* check if we should use HTTP instead */
1099	if (purl && strcasecmp(purl->scheme, SCHEME_HTTP) == 0) {
1100		if (strcmp(op, "STAT") == 0)
1101			return (http_request(url, "HEAD", us, purl, flags));
1102		else if (strcmp(op, "RETR") == 0)
1103			return (http_request(url, "GET", us, purl, flags));
1104		/*
1105		 * Our HTTP code doesn't support PUT requests yet, so try
1106		 * a direct connection.
1107		 */
1108	}
1109
1110	/* connect to server */
1111	conn = ftp_cached_connect(url, purl, flags);
1112	if (purl)
1113		fetchFreeURL(purl);
1114	if (conn == NULL)
1115		return (NULL);
1116
1117	/* change directory */
1118	if (ftp_cwd(conn, url->doc) == -1)
1119		return (NULL);
1120
1121	/* stat file */
1122	if (us && ftp_stat(conn, url->doc, us) == -1
1123	    && fetchLastErrCode != FETCH_PROTO
1124	    && fetchLastErrCode != FETCH_UNAVAIL)
1125		return (NULL);
1126
1127	/* just a stat */
1128	if (strcmp(op, "STAT") == 0)
1129		return (FILE *)1; /* bogus return value */
1130	if (strcmp(op, "STOR") == 0 || strcmp(op, "APPE") == 0)
1131		oflag = O_WRONLY;
1132	else
1133		oflag = O_RDONLY;
1134
1135	/* initiate the transfer */
1136	return (ftp_transfer(conn, op, url->doc, oflag, url->offset, flags));
1137}
1138
1139/*
1140 * Get and stat file
1141 */
1142FILE *
1143fetchXGetFTP(struct url *url, struct url_stat *us, const char *flags)
1144{
1145	return (ftp_request(url, "RETR", us, ftp_get_proxy(url, flags), flags));
1146}
1147
1148/*
1149 * Get file
1150 */
1151FILE *
1152fetchGetFTP(struct url *url, const char *flags)
1153{
1154	return (fetchXGetFTP(url, NULL, flags));
1155}
1156
1157/*
1158 * Put file
1159 */
1160FILE *
1161fetchPutFTP(struct url *url, const char *flags)
1162{
1163	return (ftp_request(url, CHECK_FLAG('a') ? "APPE" : "STOR", NULL,
1164	    ftp_get_proxy(url, flags), flags));
1165}
1166
1167/*
1168 * Get file stats
1169 */
1170int
1171fetchStatFTP(struct url *url, struct url_stat *us, const char *flags)
1172{
1173	FILE *f;
1174
1175	f = ftp_request(url, "STAT", us, ftp_get_proxy(url, flags), flags);
1176	if (f == NULL)
1177		return (-1);
1178	fclose(f);
1179	return (0);
1180}
1181
1182/*
1183 * List a directory
1184 */
1185struct url_ent *
1186fetchListFTP(struct url *url __unused, const char *flags __unused)
1187{
1188	warnx("fetchListFTP(): not implemented");
1189	return (NULL);
1190}
1191