ftp.c revision 67430 
1/*-
2 * Copyright (c) 1998 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 * $FreeBSD: head/lib/libfetch/ftp.c 67430 2000-10-22 12:07:28Z des $
29 */
30
31/*
32 * Portions of this code were taken from or based on ftpio.c:
33 *
34 * ----------------------------------------------------------------------------
35 * "THE BEER-WARE LICENSE" (Revision 42):
36 * <phk@login.dknet.dk> wrote this file.  As long as you retain this notice you
37 * can do whatever you want with this stuff. If we meet some day, and you think
38 * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
39 * ----------------------------------------------------------------------------
40 *
41 * Major Changelog:
42 *
43 * Dag-Erling Co�dan Sm�rgrav
44 * 9 Jun 1998
45 *
46 * Incorporated into libfetch
47 *
48 * Jordan K. Hubbard
49 * 17 Jan 1996
50 *
51 * Turned inside out. Now returns xfers as new file ids, not as a special
52 * `state' of FTP_t
53 *
54 * $ftpioId: ftpio.c,v 1.30 1998/04/11 07:28:53 phk Exp $
55 *
56 */
57
58#include <sys/param.h>
59#include <sys/socket.h>
60#include <netinet/in.h>
61
62#include <ctype.h>
63#include <errno.h>
64#include <fcntl.h>
65#include <netdb.h>
66#include <stdarg.h>
67#include <stdio.h>
68#include <stdlib.h>
69#include <string.h>
70#include <time.h>
71#include <unistd.h>
72
73#include "fetch.h"
74#include "common.h"
75#include "ftperr.h"
76
77#define FTP_ANONYMOUS_USER	"ftp"
78#define FTP_ANONYMOUS_PASSWORD	"ftp"
79
80#define FTP_CONNECTION_ALREADY_OPEN	125
81#define FTP_OPEN_DATA_CONNECTION	150
82#define FTP_OK				200
83#define FTP_FILE_STATUS			213
84#define FTP_SERVICE_READY		220
85#define FTP_PASSIVE_MODE		227
86#define FTP_LPASSIVE_MODE		228
87#define FTP_EPASSIVE_MODE		229
88#define FTP_LOGGED_IN			230
89#define FTP_FILE_ACTION_OK		250
90#define FTP_NEED_PASSWORD		331
91#define FTP_NEED_ACCOUNT		332
92#define FTP_FILE_OK			350
93#define FTP_SYNTAX_ERROR		500
94#define FTP_PROTOCOL_ERROR		999
95
96static struct url cached_host;
97static int cached_socket;
98
99static char *last_reply;
100static size_t lr_size, lr_length;
101static int last_code;
102
103#define isftpreply(foo) (isdigit(foo[0]) && isdigit(foo[1]) \
104			 && isdigit(foo[2]) \
105                         && (foo[3] == ' ' || foo[3] == '\0'))
106#define isftpinfo(foo) (isdigit(foo[0]) && isdigit(foo[1]) \
107			&& isdigit(foo[2]) && foo[3] == '-')
108
109/* translate IPv4 mapped IPv6 address to IPv4 address */
110static void
111unmappedaddr(struct sockaddr_in6 *sin6)
112{
113    struct sockaddr_in *sin4;
114    u_int32_t addr;
115    int port;
116
117    if (sin6->sin6_family != AF_INET6 ||
118	!IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
119	return;
120    sin4 = (struct sockaddr_in *)sin6;
121    addr = *(u_int32_t *)&sin6->sin6_addr.s6_addr[12];
122    port = sin6->sin6_port;
123    memset(sin4, 0, sizeof(struct sockaddr_in));
124    sin4->sin_addr.s_addr = addr;
125    sin4->sin_port = port;
126    sin4->sin_family = AF_INET;
127    sin4->sin_len = sizeof(struct sockaddr_in);
128}
129
130/*
131 * Get server response
132 */
133static int
134_ftp_chkerr(int cd)
135{
136    if (_fetch_getln(cd, &last_reply, &lr_size, &lr_length) == -1) {
137	_fetch_syserr();
138	return -1;
139    }
140    if (isftpinfo(last_reply)) {
141	while (!isftpreply(last_reply)) {
142	    if (_fetch_getln(cd, &last_reply, &lr_size, &lr_length) == -1) {
143		_fetch_syserr();
144		return -1;
145	    }
146	}
147    }
148
149    while (lr_length && isspace(last_reply[lr_length-1]))
150	lr_length--;
151    last_reply[lr_length] = 0;
152
153    if (!isftpreply(last_reply)) {
154	_ftp_seterr(FTP_PROTOCOL_ERROR);
155	return -1;
156    }
157
158    last_code = (last_reply[0] - '0') * 100
159	+ (last_reply[1] - '0') * 10
160	+ (last_reply[2] - '0');
161
162    return last_code;
163}
164
165/*
166 * Send a command and check reply
167 */
168static int
169_ftp_cmd(int cd, char *fmt, ...)
170{
171    va_list ap;
172    size_t len;
173    char *msg;
174    int r;
175
176    va_start(ap, fmt);
177    len = vasprintf(&msg, fmt, ap);
178    va_end(ap);
179
180    if (msg == NULL) {
181	errno = ENOMEM;
182	_fetch_syserr();
183	return -1;
184    }
185
186    r = _fetch_putln(cd, msg, len);
187    free(msg);
188
189    if (r == -1) {
190	_fetch_syserr();
191	return -1;
192    }
193
194    return _ftp_chkerr(cd);
195}
196
197/*
198 * Return a pointer to the filename part of a path
199 */
200static char *
201_ftp_filename(char *file)
202{
203    char *s;
204
205    if ((s = strrchr(file, '/')) == NULL)
206	return file;
207    else
208	return s + 1;
209}
210
211/*
212 * Change working directory to the directory that contains the
213 * specified file.
214 */
215static int
216_ftp_cwd(int cd, char *file)
217{
218    char *s;
219    int e;
220
221    if ((s = strrchr(file, '/')) == NULL || s == file) {
222	e = _ftp_cmd(cd, "CWD /");
223    } else {
224	e = _ftp_cmd(cd, "CWD %.*s", s - file, file);
225    }
226    if (e != FTP_FILE_ACTION_OK) {
227	_ftp_seterr(e);
228	return -1;
229    }
230    return 0;
231}
232
233/*
234 * Request and parse file stats
235 */
236static int
237_ftp_stat(int cd, char *file, struct url_stat *us)
238{
239    char *ln, *s;
240    struct tm tm;
241    time_t t;
242    int e;
243
244    us->size = -1;
245    us->atime = us->mtime = 0;
246
247    if ((s = strrchr(file, '/')) == NULL)
248	s = file;
249    else
250	++s;
251
252    if ((e = _ftp_cmd(cd, "SIZE %s", s)) != FTP_FILE_STATUS) {
253	_ftp_seterr(e);
254	return -1;
255    }
256    for (ln = last_reply + 4; *ln && isspace(*ln); ln++)
257	/* nothing */ ;
258    for (us->size = 0; *ln && isdigit(*ln); ln++)
259	us->size = us->size * 10 + *ln - '0';
260    if (*ln && !isspace(*ln)) {
261	_ftp_seterr(FTP_PROTOCOL_ERROR);
262	return -1;
263    }
264    if (us->size == 0)
265	us->size = -1;
266    DEBUG(fprintf(stderr, "size: [\033[1m%lld\033[m]\n", us->size));
267
268    if ((e = _ftp_cmd(cd, "MDTM %s", s)) != FTP_FILE_STATUS) {
269	_ftp_seterr(e);
270	return -1;
271    }
272    for (ln = last_reply + 4; *ln && isspace(*ln); ln++)
273	/* nothing */ ;
274    switch (strspn(ln, "0123456789")) {
275    case 14:
276	break;
277    case 15:
278	ln++;
279	ln[0] = '2';
280	ln[1] = '0';
281	break;
282    default:
283	_ftp_seterr(FTP_PROTOCOL_ERROR);
284	return -1;
285    }
286    if (sscanf(ln, "%04d%02d%02d%02d%02d%02d",
287	       &tm.tm_year, &tm.tm_mon, &tm.tm_mday,
288	       &tm.tm_hour, &tm.tm_min, &tm.tm_sec) != 6) {
289	_ftp_seterr(FTP_PROTOCOL_ERROR);
290	return -1;
291    }
292    tm.tm_mon--;
293    tm.tm_year -= 1900;
294    tm.tm_isdst = -1;
295    t = timegm(&tm);
296    if (t == (time_t)-1)
297	t = time(NULL);
298    us->mtime = t;
299    us->atime = t;
300    DEBUG(fprintf(stderr, "last modified: [\033[1m%04d-%02d-%02d "
301		  "%02d:%02d:%02d\033[m]\n",
302		  tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
303		  tm.tm_hour, tm.tm_min, tm.tm_sec));
304    return 0;
305}
306
307/*
308 * I/O functions for FTP
309 */
310struct ftpio {
311    int		 csd;		/* Control socket descriptor */
312    int		 dsd;		/* Data socket descriptor */
313    int		 dir;		/* Direction */
314    int		 eof;		/* EOF reached */
315    int		 err;		/* Error code */
316};
317
318static int	_ftp_readfn(void *, char *, int);
319static int	_ftp_writefn(void *, const char *, int);
320static fpos_t	_ftp_seekfn(void *, fpos_t, int);
321static int	_ftp_closefn(void *);
322
323static int
324_ftp_readfn(void *v, char *buf, int len)
325{
326    struct ftpio *io;
327    int r;
328
329    io = (struct ftpio *)v;
330    if (io->csd == -1 || io->dsd == -1 || io->dir == O_WRONLY) {
331	errno = EBADF;
332	return -1;
333    }
334    if (io->err) {
335	errno = io->err;
336	return -1;
337    }
338    if (io->eof)
339	return 0;
340    r = read(io->dsd, buf, len);
341    if (r > 0)
342	return r;
343    if (r == 0) {
344	io->eof = 1;
345	return _ftp_closefn(v);
346    }
347    io->err = errno;
348    return -1;
349}
350
351static int
352_ftp_writefn(void *v, const char *buf, int len)
353{
354    struct ftpio *io;
355    int w;
356
357    io = (struct ftpio *)v;
358    if (io->csd == -1 || io->dsd == -1 || io->dir == O_RDONLY) {
359	errno = EBADF;
360	return -1;
361    }
362    if (io->err) {
363	errno = io->err;
364	return -1;
365    }
366    w = write(io->dsd, buf, len);
367    if (w >= 0)
368	return w;
369    io->err = errno;
370    return -1;
371}
372
373static fpos_t
374_ftp_seekfn(void *v, fpos_t pos, int whence)
375{
376    errno = ESPIPE;
377    return -1;
378}
379
380static int
381_ftp_closefn(void *v)
382{
383    struct ftpio *io;
384
385    io = (struct ftpio *)v;
386    if (io->dir == -1)
387	return 0;
388    if (io->csd == -1 || io->dsd == -1) {
389	errno = EBADF;
390	return -1;
391    }
392    io->err = _ftp_chkerr(io->csd);
393    io->dir = -1;
394    if (close(io->dsd) == -1)
395	return -1;
396    io->dsd = -1;
397    close(io->csd);
398    io->csd = -1;
399    return io->err ? -1 : 0;
400}
401
402static FILE *
403_ftp_setup(int csd, int dsd, int mode)
404{
405    struct ftpio *io;
406    FILE *f;
407
408    if ((io = malloc(sizeof *io)) == NULL)
409	return NULL;
410    io->csd = dup(csd);
411    io->dsd = dsd;
412    io->dir = mode;
413    io->eof = io->err = 0;
414    f = funopen(io, _ftp_readfn, _ftp_writefn, _ftp_seekfn, _ftp_closefn);
415    if (f == NULL)
416	free(io);
417    return f;
418}
419
420/*
421 * Transfer file
422 */
423static FILE *
424_ftp_transfer(int cd, char *oper, char *file,
425	      int mode, off_t offset, char *flags)
426{
427    struct sockaddr_storage sin;
428    struct sockaddr_in6 *sin6;
429    struct sockaddr_in *sin4;
430    int pasv, high, verbose;
431    int e, sd = -1;
432    socklen_t l;
433    char *s;
434    FILE *df;
435
436    /* check flags */
437    pasv = (flags && strchr(flags, 'p'));
438    high = (flags && strchr(flags, 'h'));
439    verbose = (flags && strchr(flags, 'v'));
440
441    /* passive mode */
442    if (!pasv)
443	pasv = ((s = getenv("FTP_PASSIVE_MODE")) == NULL ||
444		strncasecmp(s, "no", 2) != 0);
445
446    /* find our own address, bind, and listen */
447    l = sizeof sin;
448    if (getsockname(cd, (struct sockaddr *)&sin, &l) == -1)
449	goto sysouch;
450    if (sin.ss_family == AF_INET6)
451	unmappedaddr((struct sockaddr_in6 *)&sin);
452
453    /* open data socket */
454    if ((sd = socket(sin.ss_family, SOCK_STREAM, IPPROTO_TCP)) == -1) {
455	_fetch_syserr();
456	return NULL;
457    }
458
459    if (pasv) {
460	u_char addr[64];
461	char *ln, *p;
462	int i;
463	int port;
464
465	/* send PASV command */
466	if (verbose)
467	    _fetch_info("setting passive mode");
468	switch (sin.ss_family) {
469	case AF_INET:
470	    if ((e = _ftp_cmd(cd, "PASV")) != FTP_PASSIVE_MODE)
471		goto ouch;
472	    break;
473	case AF_INET6:
474	    if ((e = _ftp_cmd(cd, "EPSV")) != FTP_EPASSIVE_MODE) {
475		if (e == -1)
476		    goto ouch;
477		if ((e = _ftp_cmd(cd, "LPSV")) != FTP_LPASSIVE_MODE)
478		    goto ouch;
479	    }
480	    break;
481	default:
482	    e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
483	    goto ouch;
484	}
485
486	/*
487	 * Find address and port number. The reply to the PASV command
488         * is IMHO the one and only weak point in the FTP protocol.
489	 */
490	ln = last_reply;
491      	switch (e) {
492	case FTP_PASSIVE_MODE:
493	case FTP_LPASSIVE_MODE:
494	    for (p = ln + 3; *p && !isdigit(*p); p++)
495		/* nothing */ ;
496	    if (!*p) {
497		e = FTP_PROTOCOL_ERROR;
498		goto ouch;
499	    }
500	    l = (e == FTP_PASSIVE_MODE ? 6 : 21);
501	    for (i = 0; *p && i < l; i++, p++)
502		addr[i] = strtol(p, &p, 10);
503	    if (i < l) {
504		e = FTP_PROTOCOL_ERROR;
505		goto ouch;
506	    }
507	    break;
508	case FTP_EPASSIVE_MODE:
509	    for (p = ln + 3; *p && *p != '('; p++)
510		/* nothing */ ;
511	    if (!*p) {
512		e = FTP_PROTOCOL_ERROR;
513		goto ouch;
514	    }
515	    ++p;
516	    if (sscanf(p, "%c%c%c%d%c", &addr[0], &addr[1], &addr[2],
517		       &port, &addr[3]) != 5 ||
518		addr[0] != addr[1] ||
519		addr[0] != addr[2] || addr[0] != addr[3]) {
520		e = FTP_PROTOCOL_ERROR;
521		goto ouch;
522	    }
523	    break;
524	}
525
526	/* seek to required offset */
527	if (offset)
528	    if (_ftp_cmd(cd, "REST %lu", (u_long)offset) != FTP_FILE_OK)
529		goto sysouch;
530
531	/* construct sockaddr for data socket */
532	l = sizeof sin;
533	if (getpeername(cd, (struct sockaddr *)&sin, &l) == -1)
534	    goto sysouch;
535	if (sin.ss_family == AF_INET6)
536	    unmappedaddr((struct sockaddr_in6 *)&sin);
537	switch (sin.ss_family) {
538	case AF_INET6:
539	    sin6 = (struct sockaddr_in6 *)&sin;
540	    if (e == FTP_EPASSIVE_MODE)
541		sin6->sin6_port = htons(port);
542	    else {
543		bcopy(addr + 2, (char *)&sin6->sin6_addr, 16);
544		bcopy(addr + 19, (char *)&sin6->sin6_port, 2);
545	    }
546	    break;
547	case AF_INET:
548	    sin4 = (struct sockaddr_in *)&sin;
549	    if (e == FTP_EPASSIVE_MODE)
550		sin4->sin_port = htons(port);
551	    else {
552		bcopy(addr, (char *)&sin4->sin_addr, 4);
553		bcopy(addr + 4, (char *)&sin4->sin_port, 2);
554	    }
555	    break;
556	default:
557	    e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
558	    break;
559	}
560
561	/* connect to data port */
562	if (verbose)
563	    _fetch_info("opening data connection");
564	if (connect(sd, (struct sockaddr *)&sin, sin.ss_len) == -1)
565	    goto sysouch;
566
567	/* make the server initiate the transfer */
568	if (verbose)
569	    _fetch_info("initiating transfer");
570	e = _ftp_cmd(cd, "%s %s", oper, _ftp_filename(file));
571	if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
572	    goto ouch;
573
574    } else {
575	u_int32_t a;
576	u_short p;
577	int arg, d;
578	char *ap;
579	char hname[INET6_ADDRSTRLEN];
580
581	switch (sin.ss_family) {
582	case AF_INET6:
583	    ((struct sockaddr_in6 *)&sin)->sin6_port = 0;
584#ifdef IPV6_PORTRANGE
585	    arg = high ? IPV6_PORTRANGE_HIGH : IPV6_PORTRANGE_DEFAULT;
586	    if (setsockopt(sd, IPPROTO_IPV6, IPV6_PORTRANGE,
587			   (char *)&arg, sizeof(arg)) == -1)
588		goto sysouch;
589#endif
590	    break;
591	case AF_INET:
592	    ((struct sockaddr_in *)&sin)->sin_port = 0;
593	    arg = high ? IP_PORTRANGE_HIGH : IP_PORTRANGE_DEFAULT;
594	    if (setsockopt(sd, IPPROTO_IP, IP_PORTRANGE,
595			   (char *)&arg, sizeof arg) == -1)
596		goto sysouch;
597	    break;
598	}
599	if (verbose)
600	    _fetch_info("binding data socket");
601	if (bind(sd, (struct sockaddr *)&sin, sin.ss_len) == -1)
602	    goto sysouch;
603	if (listen(sd, 1) == -1)
604	    goto sysouch;
605
606	/* find what port we're on and tell the server */
607	if (getsockname(sd, (struct sockaddr *)&sin, &l) == -1)
608	    goto sysouch;
609	switch (sin.ss_family) {
610	case AF_INET:
611	    sin4 = (struct sockaddr_in *)&sin;
612	    a = ntohl(sin4->sin_addr.s_addr);
613	    p = ntohs(sin4->sin_port);
614	    e = _ftp_cmd(cd, "PORT %d,%d,%d,%d,%d,%d",
615			 (a >> 24) & 0xff, (a >> 16) & 0xff,
616			 (a >> 8) & 0xff, a & 0xff,
617			 (p >> 8) & 0xff, p & 0xff);
618	    break;
619	case AF_INET6:
620#define UC(b)	(((int)b)&0xff)
621	    e = -1;
622	    sin6 = (struct sockaddr_in6 *)&sin;
623	    if (getnameinfo((struct sockaddr *)&sin, sin.ss_len,
624			    hname, sizeof(hname),
625			    NULL, 0, NI_NUMERICHOST) == 0) {
626		e = _ftp_cmd(cd, "EPRT |%d|%s|%d|", 2, hname,
627			     htons(sin6->sin6_port));
628		if (e == -1)
629		    goto ouch;
630	    }
631	    if (e != FTP_OK) {
632		ap = (char *)&sin6->sin6_addr;
633		e = _ftp_cmd(cd,
634     "LPRT %d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d",
635			     6, 16,
636			     UC(ap[0]), UC(ap[1]), UC(ap[2]), UC(ap[3]),
637			     UC(ap[4]), UC(ap[5]), UC(ap[6]), UC(ap[7]),
638			     UC(ap[8]), UC(ap[9]), UC(ap[10]), UC(ap[11]),
639			     UC(ap[12]), UC(ap[13]), UC(ap[14]), UC(ap[15]),
640			     2,
641			     (ntohs(sin6->sin6_port) >> 8) & 0xff,
642			     ntohs(sin6->sin6_port)        & 0xff);
643	    }
644	    break;
645	default:
646	    e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
647	    goto ouch;
648	}
649	if (e != FTP_OK)
650	    goto ouch;
651
652	/* seek to required offset */
653	if (offset)
654	    if (_ftp_cmd(cd, "REST %lu", (u_long)offset) != FTP_FILE_OK)
655		goto sysouch;
656
657	/* make the server initiate the transfer */
658	if (verbose)
659	    _fetch_info("initiating transfer");
660	e = _ftp_cmd(cd, "%s %s", oper, _ftp_filename(file));
661	if (e != FTP_OPEN_DATA_CONNECTION)
662	    goto ouch;
663
664	/* accept the incoming connection and go to town */
665	if ((d = accept(sd, NULL, NULL)) == -1)
666	    goto sysouch;
667	close(sd);
668	sd = d;
669    }
670
671    if ((df = _ftp_setup(cd, sd, mode)) == NULL)
672	goto sysouch;
673    return df;
674
675sysouch:
676    _fetch_syserr();
677    if (sd >= 0)
678	close(sd);
679    return NULL;
680
681ouch:
682    if (e != -1)
683	_ftp_seterr(e);
684    if (sd >= 0)
685	close(sd);
686    return NULL;
687}
688
689/*
690 * Return default port
691 */
692static int
693_ftp_default_port(void)
694{
695    struct servent *se;
696
697    if ((se = getservbyname(SCHEME_FTP, "tcp")) != NULL)
698	return ntohs(se->s_port);
699    return FTP_DEFAULT_PORT;
700}
701
702/*
703 * Log on to FTP server
704 */
705static int
706_ftp_connect(struct url *url, struct url *purl, char *flags)
707{
708    int cd, e, direct, verbose;
709#ifdef INET6
710    int af = AF_UNSPEC;
711#else
712    int af = AF_INET;
713#endif
714    const char *logname;
715    char *user, *pwd;
716    char localhost[MAXHOSTNAMELEN];
717    char pbuf[MAXHOSTNAMELEN + MAXLOGNAME + 1];
718
719    direct = (flags && strchr(flags, 'd'));
720    verbose = (flags && strchr(flags, 'v'));
721    if ((flags && strchr(flags, '4')))
722	af = AF_INET;
723    else if ((flags && strchr(flags, '6')))
724	af = AF_INET6;
725
726    if (direct)
727	purl = NULL;
728
729    /* check for proxy */
730    if (purl) {
731	/* XXX proxy authentication! */
732	cd = _fetch_connect(purl->host, purl->port, af, verbose);
733    } else {
734	/* no proxy, go straight to target */
735	cd = _fetch_connect(url->host, url->port, af, verbose);
736	purl = NULL;
737    }
738
739    /* check connection */
740    if (cd == -1) {
741	_fetch_syserr();
742	return NULL;
743    }
744
745    /* expect welcome message */
746    if ((e = _ftp_chkerr(cd)) != FTP_SERVICE_READY)
747	goto fouch;
748
749    /* XXX FTP_AUTH, and maybe .netrc */
750
751    /* send user name and password */
752    user = url->user;
753    if (!user || !*user)
754	user = FTP_ANONYMOUS_USER;
755    if (purl && url->port == FTP_DEFAULT_PORT)
756	e = _ftp_cmd(cd, "USER %s@%s", user, url->host);
757    else if (purl)
758	e = _ftp_cmd(cd, "USER %s@%s@%d", user, url->host, url->port);
759    else
760	e = _ftp_cmd(cd, "USER %s", user);
761
762    /* did the server request a password? */
763    if (e == FTP_NEED_PASSWORD) {
764	pwd = url->pwd;
765	if (!pwd || !*pwd)
766	    pwd = getenv("FTP_PASSWORD");
767	if (!pwd || !*pwd) {
768	    if ((logname = getlogin()) == 0)
769		logname = FTP_ANONYMOUS_PASSWORD;
770	    gethostname(localhost, sizeof localhost);
771	    snprintf(pbuf, sizeof pbuf, "%s@%s", logname, localhost);
772	    pwd = pbuf;
773	}
774	e = _ftp_cmd(cd, "PASS %s", pwd);
775    }
776
777    /* did the server request an account? */
778    if (e == FTP_NEED_ACCOUNT)
779	goto fouch;
780
781    /* we should be done by now */
782    if (e != FTP_LOGGED_IN)
783	goto fouch;
784
785    /* might as well select mode and type at once */
786#ifdef FTP_FORCE_STREAM_MODE
787    if ((e = _ftp_cmd(cd, "MODE S")) != FTP_OK) /* default is S */
788	goto fouch;
789#endif
790    if ((e = _ftp_cmd(cd, "TYPE I")) != FTP_OK) /* default is A */
791	goto fouch;
792
793    /* done */
794    return cd;
795
796fouch:
797    if (e != -1)
798	_ftp_seterr(e);
799    close(cd);
800    return NULL;
801}
802
803/*
804 * Disconnect from server
805 */
806static void
807_ftp_disconnect(int cd)
808{
809    (void)_ftp_cmd(cd, "QUIT");
810    close(cd);
811}
812
813/*
814 * Check if we're already connected
815 */
816static int
817_ftp_isconnected(struct url *url)
818{
819    return (cached_socket
820	    && (strcmp(url->host, cached_host.host) == 0)
821	    && (strcmp(url->user, cached_host.user) == 0)
822	    && (strcmp(url->pwd, cached_host.pwd) == 0)
823	    && (url->port == cached_host.port));
824}
825
826/*
827 * Check the cache, reconnect if no luck
828 */
829static int
830_ftp_cached_connect(struct url *url, struct url *purl, char *flags)
831{
832    int e, cd;
833
834    cd = -1;
835
836    /* set default port */
837    if (!url->port)
838	url->port = _ftp_default_port();
839
840    /* try to use previously cached connection */
841    if (_ftp_isconnected(url)) {
842	e = _ftp_cmd(cached_socket, "NOOP");
843	if (e == FTP_OK || e == FTP_SYNTAX_ERROR)
844	    return cached_socket;
845    }
846
847    /* connect to server */
848    if ((cd = _ftp_connect(url, purl, flags)) == -1)
849	return -1;
850    if (cached_socket)
851	_ftp_disconnect(cached_socket);
852    cached_socket = cd;
853    memcpy(&cached_host, url, sizeof *url);
854    return cd;
855}
856
857/*
858 * Check the proxy settings
859 */
860static struct url *
861_ftp_get_proxy(void)
862{
863    struct url *purl;
864    char *p;
865
866    if (((p = getenv("FTP_PROXY")) || (p = getenv("HTTP_PROXY"))) &&
867	*p && (purl = fetchParseURL(p)) != NULL) {
868	if (!*purl->scheme)
869	    strcpy(purl->scheme, SCHEME_FTP);
870	if (!purl->port)
871	    purl->port = _ftp_default_port();
872	if (strcasecmp(purl->scheme, SCHEME_FTP) == 0 ||
873	    strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
874	    return purl;
875	fetchFreeURL(purl);
876    }
877    return NULL;
878}
879
880/*
881 * Get and stat file
882 */
883FILE *
884fetchXGetFTP(struct url *url, struct url_stat *us, char *flags)
885{
886    struct url *purl;
887    int cd;
888
889    /* get the proxy URL, and check if we should use HTTP instead */
890    if (!strchr(flags, 'd') && (purl = _ftp_get_proxy()) != NULL) {
891	if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
892	    return _http_request(url, "GET", us, purl, flags);
893    } else {
894	purl = NULL;
895    }
896
897    /* connect to server */
898    cd = _ftp_cached_connect(url, purl, flags);
899    if (purl)
900	fetchFreeURL(purl);
901    if (cd == NULL)
902	return NULL;
903
904    /* change directory */
905    if (_ftp_cwd(cd, url->doc) == -1)
906	return NULL;
907
908    /* stat file */
909    if (us && _ftp_stat(cd, url->doc, us) == -1
910	&& fetchLastErrCode != FETCH_PROTO
911	&& fetchLastErrCode != FETCH_UNAVAIL)
912	return NULL;
913
914    /* initiate the transfer */
915    return _ftp_transfer(cd, "RETR", url->doc, O_RDONLY, url->offset, flags);
916}
917
918/*
919 * Get file
920 */
921FILE *
922fetchGetFTP(struct url *url, char *flags)
923{
924    return fetchXGetFTP(url, NULL, flags);
925}
926
927/*
928 * Put file
929 */
930FILE *
931fetchPutFTP(struct url *url, char *flags)
932{
933    struct url *purl;
934    int cd;
935
936    /* get the proxy URL, and check if we should use HTTP instead */
937    if (!strchr(flags, 'd') && (purl = _ftp_get_proxy()) != NULL) {
938	if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
939	    /* XXX HTTP PUT is not implemented, so try without the proxy */
940	    purl = NULL;
941    } else {
942	purl = NULL;
943    }
944
945    /* connect to server */
946    cd = _ftp_cached_connect(url, purl, flags);
947    if (purl)
948	fetchFreeURL(purl);
949    if (cd == NULL)
950	return NULL;
951
952    /* change directory */
953    if (_ftp_cwd(cd, url->doc) == -1)
954	return NULL;
955
956    /* initiate the transfer */
957    return _ftp_transfer(cd, (flags && strchr(flags, 'a')) ? "APPE" : "STOR",
958			 url->doc, O_WRONLY, url->offset, flags);
959}
960
961/*
962 * Get file stats
963 */
964int
965fetchStatFTP(struct url *url, struct url_stat *us, char *flags)
966{
967    struct url *purl;
968    int cd;
969
970    /* get the proxy URL, and check if we should use HTTP instead */
971    if (!strchr(flags, 'd') && (purl = _ftp_get_proxy()) != NULL) {
972	if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0) {
973	    FILE *f;
974
975	    if ((f = _http_request(url, "HEAD", us, purl, flags)) == NULL)
976		return -1;
977	    fclose(f);
978	    return 0;
979	}
980    } else {
981	purl = NULL;
982    }
983
984    /* connect to server */
985    cd = _ftp_cached_connect(url, purl, flags);
986    if (purl)
987	fetchFreeURL(purl);
988    if (cd == NULL)
989	return NULL;
990
991    /* change directory */
992    if (_ftp_cwd(cd, url->doc) == -1)
993	return -1;
994
995    /* stat file */
996    return _ftp_stat(cd, url->doc, us);
997}
998
999/*
1000 * List a directory
1001 */
1002extern void warnx(char *, ...);
1003struct url_ent *
1004fetchListFTP(struct url *url, char *flags)
1005{
1006    warnx("fetchListFTP(): not implemented");
1007    return NULL;
1008}
1009