ftp.c revision 63910 
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 63910 2000-07-27 08:48:48Z 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 <netdb.h>
65#include <stdarg.h>
66#include <stdio.h>
67#include <stdlib.h>
68#include <string.h>
69#include <time.h>
70#include <unistd.h>
71
72#include "fetch.h"
73#include "common.h"
74#include "ftperr.h"
75
76#define FTP_ANONYMOUS_USER	"ftp"
77#define FTP_ANONYMOUS_PASSWORD	"ftp"
78
79#define FTP_OPEN_DATA_CONNECTION	150
80#define FTP_OK				200
81#define FTP_FILE_STATUS			213
82#define FTP_SERVICE_READY		220
83#define FTP_PASSIVE_MODE		227
84#define FTP_LPASSIVE_MODE		228
85#define FTP_EPASSIVE_MODE		229
86#define FTP_LOGGED_IN			230
87#define FTP_FILE_ACTION_OK		250
88#define FTP_NEED_PASSWORD		331
89#define FTP_NEED_ACCOUNT		332
90#define FTP_FILE_OK			350
91#define FTP_SYNTAX_ERROR		500
92#define FTP_PROTOCOL_ERROR		999
93
94static struct url cached_host;
95static int cached_socket;
96
97static char *last_reply;
98static size_t lr_size, lr_length;
99static int last_code;
100
101#define isftpreply(foo) (isdigit(foo[0]) && isdigit(foo[1]) \
102			 && isdigit(foo[2]) \
103                         && (foo[3] == ' ' || foo[3] == '\0'))
104#define isftpinfo(foo) (isdigit(foo[0]) && isdigit(foo[1]) \
105			&& isdigit(foo[2]) && foo[3] == '-')
106
107/* translate IPv4 mapped IPv6 address to IPv4 address */
108static void
109unmappedaddr(struct sockaddr_in6 *sin6)
110{
111    struct sockaddr_in *sin4;
112    u_int32_t addr;
113    int port;
114
115    if (sin6->sin6_family != AF_INET6 ||
116	!IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
117	return;
118    sin4 = (struct sockaddr_in *)sin6;
119    addr = *(u_int32_t *)&sin6->sin6_addr.s6_addr[12];
120    port = sin6->sin6_port;
121    memset(sin4, 0, sizeof(struct sockaddr_in));
122    sin4->sin_addr.s_addr = addr;
123    sin4->sin_port = port;
124    sin4->sin_family = AF_INET;
125    sin4->sin_len = sizeof(struct sockaddr_in);
126}
127
128/*
129 * Get server response
130 */
131static int
132_ftp_chkerr(int cd)
133{
134    if (_fetch_getln(cd, &last_reply, &lr_size, &lr_length) == -1) {
135	_fetch_syserr();
136	return -1;
137    }
138    if (isftpinfo(last_reply)) {
139	while (!isftpreply(last_reply)) {
140	    if (_fetch_getln(cd, &last_reply, &lr_size, &lr_length) == -1) {
141		_fetch_syserr();
142		return -1;
143	    }
144	}
145    }
146
147    while (lr_length && isspace(last_reply[lr_length-1]))
148	lr_length--;
149    last_reply[lr_length] = 0;
150
151    if (!isftpreply(last_reply)) {
152	_ftp_seterr(FTP_PROTOCOL_ERROR);
153	return -1;
154    }
155
156    last_code = (last_reply[0] - '0') * 100
157	+ (last_reply[1] - '0') * 10
158	+ (last_reply[2] - '0');
159
160    return last_code;
161}
162
163/*
164 * Send a command and check reply
165 */
166static int
167_ftp_cmd(int cd, char *fmt, ...)
168{
169    va_list ap;
170    size_t len;
171    char *msg;
172    int r;
173
174    va_start(ap, fmt);
175    len = vasprintf(&msg, fmt, ap);
176    va_end(ap);
177
178    if (msg == NULL) {
179	errno = ENOMEM;
180	_fetch_syserr();
181	return -1;
182    }
183
184    r = _fetch_putln(cd, msg, len);
185    free(msg);
186
187    if (r == -1) {
188	_fetch_syserr();
189	return -1;
190    }
191
192    return _ftp_chkerr(cd);
193}
194
195/*
196 * Return a pointer to the filename part of a path
197 */
198static char *
199_ftp_filename(char *file)
200{
201    char *s;
202
203    if ((s = strrchr(file, '/')) == NULL)
204	return file;
205    else
206	return s + 1;
207}
208
209/*
210 * Change working directory to the directory that contains the
211 * specified file.
212 */
213static int
214_ftp_cwd(int cd, char *file)
215{
216    char *s;
217    int e;
218
219    if ((s = strrchr(file, '/')) == NULL || s == file) {
220	e = _ftp_cmd(cd, "CWD /");
221    } else {
222	e = _ftp_cmd(cd, "CWD %.*s", s - file, file);
223    }
224    if (e != FTP_FILE_ACTION_OK) {
225	_ftp_seterr(e);
226	return -1;
227    }
228    return 0;
229}
230
231/*
232 * Request and parse file stats
233 */
234static int
235_ftp_stat(int cd, char *file, struct url_stat *us)
236{
237    char *ln, *s;
238    struct tm tm;
239    time_t t;
240    int e;
241
242    us->size = -1;
243    us->atime = us->mtime = 0;
244
245    if ((s = strrchr(file, '/')) == NULL)
246	s = file;
247    else
248	++s;
249
250    if ((e = _ftp_cmd(cd, "SIZE %s", s)) != FTP_FILE_STATUS) {
251	_ftp_seterr(e);
252	return -1;
253    }
254    for (ln = last_reply + 4; *ln && isspace(*ln); ln++)
255	/* nothing */ ;
256    for (us->size = 0; *ln && isdigit(*ln); ln++)
257	us->size = us->size * 10 + *ln - '0';
258    if (*ln && !isspace(*ln)) {
259	_ftp_seterr(FTP_PROTOCOL_ERROR);
260	return -1;
261    }
262    if (us->size == 0)
263	us->size = -1;
264    DEBUG(fprintf(stderr, "size: [\033[1m%lld\033[m]\n", us->size));
265
266    if ((e = _ftp_cmd(cd, "MDTM %s", s)) != FTP_FILE_STATUS) {
267	_ftp_seterr(e);
268	return -1;
269    }
270    for (ln = last_reply + 4; *ln && isspace(*ln); ln++)
271	/* nothing */ ;
272    switch (strspn(ln, "0123456789")) {
273    case 14:
274	break;
275    case 15:
276	ln++;
277	ln[0] = '2';
278	ln[1] = '0';
279	break;
280    default:
281	_ftp_seterr(FTP_PROTOCOL_ERROR);
282	return -1;
283    }
284    if (sscanf(ln, "%04d%02d%02d%02d%02d%02d",
285	       &tm.tm_year, &tm.tm_mon, &tm.tm_mday,
286	       &tm.tm_hour, &tm.tm_min, &tm.tm_sec) != 6) {
287	_ftp_seterr(FTP_PROTOCOL_ERROR);
288	return -1;
289    }
290    tm.tm_mon--;
291    tm.tm_year -= 1900;
292    tm.tm_isdst = -1;
293    t = timegm(&tm);
294    if (t == (time_t)-1)
295	t = time(NULL);
296    us->mtime = t;
297    us->atime = t;
298    DEBUG(fprintf(stderr, "last modified: [\033[1m%04d-%02d-%02d "
299		  "%02d:%02d:%02d\033[m]\n",
300		  tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
301		  tm.tm_hour, tm.tm_min, tm.tm_sec));
302    return 0;
303}
304
305/*
306 * Transfer file
307 */
308static FILE *
309_ftp_transfer(int cd, char *oper, char *file,
310	      char *mode, off_t offset, char *flags)
311{
312    struct sockaddr_storage sin;
313    struct sockaddr_in6 *sin6;
314    struct sockaddr_in *sin4;
315    int pasv, high, verbose;
316    int e, sd = -1;
317    socklen_t l;
318    char *s;
319    FILE *df;
320
321    /* check flags */
322    pasv = (flags && strchr(flags, 'p'));
323    high = (flags && strchr(flags, 'h'));
324    verbose = (flags && strchr(flags, 'v'));
325
326    /* passive mode */
327    if (!pasv && (s = getenv("FTP_PASSIVE_MODE")) != NULL)
328	pasv = (strncasecmp(s, "no", 2) != 0);
329
330    /* find our own address, bind, and listen */
331    l = sizeof sin;
332    if (getsockname(cd, (struct sockaddr *)&sin, &l) == -1)
333	goto sysouch;
334    if (sin.ss_family == AF_INET6)
335	unmappedaddr((struct sockaddr_in6 *)&sin);
336
337    /* open data socket */
338    if ((sd = socket(sin.ss_family, SOCK_STREAM, IPPROTO_TCP)) == -1) {
339	_fetch_syserr();
340	return NULL;
341    }
342
343    if (pasv) {
344	u_char addr[64];
345	char *ln, *p;
346	int i;
347	int port;
348
349	/* send PASV command */
350	if (verbose)
351	    _fetch_info("setting passive mode");
352	switch (sin.ss_family) {
353	case AF_INET:
354	    if ((e = _ftp_cmd(cd, "PASV")) != FTP_PASSIVE_MODE)
355		goto ouch;
356	    break;
357	case AF_INET6:
358	    if ((e = _ftp_cmd(cd, "EPSV")) != FTP_EPASSIVE_MODE) {
359		if (e == -1)
360		    goto ouch;
361		if ((e = _ftp_cmd(cd, "LPSV")) != FTP_LPASSIVE_MODE)
362		    goto ouch;
363	    }
364	    break;
365	default:
366	    e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
367	    goto ouch;
368	}
369
370	/*
371	 * Find address and port number. The reply to the PASV command
372         * is IMHO the one and only weak point in the FTP protocol.
373	 */
374	ln = last_reply;
375      	switch (e) {
376	case FTP_PASSIVE_MODE:
377	case FTP_LPASSIVE_MODE:
378	    for (p = ln + 3; *p && !isdigit(*p); p++)
379		/* nothing */ ;
380	    if (!*p) {
381		e = FTP_PROTOCOL_ERROR;
382		goto ouch;
383	    }
384	    l = (e == FTP_PASSIVE_MODE ? 6 : 21);
385	    for (i = 0; *p && i < l; i++, p++)
386		addr[i] = strtol(p, &p, 10);
387	    if (i < l) {
388		e = FTP_PROTOCOL_ERROR;
389		goto ouch;
390	    }
391	    break;
392	case FTP_EPASSIVE_MODE:
393	    for (p = ln + 3; *p && *p != '('; p++)
394		/* nothing */ ;
395	    if (!*p) {
396		e = FTP_PROTOCOL_ERROR;
397		goto ouch;
398	    }
399	    ++p;
400	    if (sscanf(p, "%c%c%c%d%c", &addr[0], &addr[1], &addr[2],
401		       &port, &addr[3]) != 5 ||
402		addr[0] != addr[1] ||
403		addr[0] != addr[2] || addr[0] != addr[3]) {
404		e = FTP_PROTOCOL_ERROR;
405		goto ouch;
406	    }
407	    break;
408	}
409
410	/* seek to required offset */
411	if (offset)
412	    if (_ftp_cmd(cd, "REST %lu", (u_long)offset) != FTP_FILE_OK)
413		goto sysouch;
414
415	/* construct sockaddr for data socket */
416	l = sizeof sin;
417	if (getpeername(cd, (struct sockaddr *)&sin, &l) == -1)
418	    goto sysouch;
419	if (sin.ss_family == AF_INET6)
420	    unmappedaddr((struct sockaddr_in6 *)&sin);
421	switch (sin.ss_family) {
422	case AF_INET6:
423	    sin6 = (struct sockaddr_in6 *)&sin;
424	    if (e == FTP_EPASSIVE_MODE)
425		sin6->sin6_port = htons(port);
426	    else {
427		bcopy(addr + 2, (char *)&sin6->sin6_addr, 16);
428		bcopy(addr + 19, (char *)&sin6->sin6_port, 2);
429	    }
430	    break;
431	case AF_INET:
432	    sin4 = (struct sockaddr_in *)&sin;
433	    if (e == FTP_EPASSIVE_MODE)
434		sin4->sin_port = htons(port);
435	    else {
436		bcopy(addr, (char *)&sin4->sin_addr, 4);
437		bcopy(addr + 4, (char *)&sin4->sin_port, 2);
438	    }
439	    break;
440	default:
441	    e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
442	    break;
443	}
444
445	/* connect to data port */
446	if (verbose)
447	    _fetch_info("opening data connection");
448	if (connect(sd, (struct sockaddr *)&sin, sin.ss_len) == -1)
449	    goto sysouch;
450
451	/* make the server initiate the transfer */
452	if (verbose)
453	    _fetch_info("initiating transfer");
454	e = _ftp_cmd(cd, "%s %s", oper, _ftp_filename(file));
455	if (e != FTP_OPEN_DATA_CONNECTION)
456	    goto ouch;
457
458    } else {
459	u_int32_t a;
460	u_short p;
461	int arg, d;
462	char *ap;
463	char hname[INET6_ADDRSTRLEN];
464
465	switch (sin.ss_family) {
466	case AF_INET6:
467	    ((struct sockaddr_in6 *)&sin)->sin6_port = 0;
468#ifdef IPV6_PORTRANGE
469	    arg = high ? IPV6_PORTRANGE_HIGH : IPV6_PORTRANGE_DEFAULT;
470	    if (setsockopt(sd, IPPROTO_IPV6, IPV6_PORTRANGE,
471			   (char *)&arg, sizeof(arg)) == -1)
472		goto sysouch;
473#endif
474	    break;
475	case AF_INET:
476	    ((struct sockaddr_in *)&sin)->sin_port = 0;
477	    arg = high ? IP_PORTRANGE_HIGH : IP_PORTRANGE_DEFAULT;
478	    if (setsockopt(sd, IPPROTO_IP, IP_PORTRANGE,
479			   (char *)&arg, sizeof arg) == -1)
480		goto sysouch;
481	    break;
482	}
483	if (verbose)
484	    _fetch_info("binding data socket");
485	if (bind(sd, (struct sockaddr *)&sin, sin.ss_len) == -1)
486	    goto sysouch;
487	if (listen(sd, 1) == -1)
488	    goto sysouch;
489
490	/* find what port we're on and tell the server */
491	if (getsockname(sd, (struct sockaddr *)&sin, &l) == -1)
492	    goto sysouch;
493	switch (sin.ss_family) {
494	case AF_INET:
495	    sin4 = (struct sockaddr_in *)&sin;
496	    a = ntohl(sin4->sin_addr.s_addr);
497	    p = ntohs(sin4->sin_port);
498	    e = _ftp_cmd(cd, "PORT %d,%d,%d,%d,%d,%d",
499			 (a >> 24) & 0xff, (a >> 16) & 0xff,
500			 (a >> 8) & 0xff, a & 0xff,
501			 (p >> 8) & 0xff, p & 0xff);
502	    break;
503	case AF_INET6:
504#define UC(b)	(((int)b)&0xff)
505	    e = -1;
506	    sin6 = (struct sockaddr_in6 *)&sin;
507	    if (getnameinfo((struct sockaddr *)&sin, sin.ss_len,
508			    hname, sizeof(hname),
509			    NULL, 0, NI_NUMERICHOST) == 0) {
510		e = _ftp_cmd(cd, "EPRT |%d|%s|%d|", 2, hname,
511			     htons(sin6->sin6_port));
512		if (e == -1)
513		    goto ouch;
514	    }
515	    if (e != FTP_OK) {
516		ap = (char *)&sin6->sin6_addr;
517		e = _ftp_cmd(cd,
518     "LPRT %d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d",
519			     6, 16,
520			     UC(ap[0]), UC(ap[1]), UC(ap[2]), UC(ap[3]),
521			     UC(ap[4]), UC(ap[5]), UC(ap[6]), UC(ap[7]),
522			     UC(ap[8]), UC(ap[9]), UC(ap[10]), UC(ap[11]),
523			     UC(ap[12]), UC(ap[13]), UC(ap[14]), UC(ap[15]),
524			     2,
525			     (ntohs(sin6->sin6_port) >> 8) & 0xff,
526			     ntohs(sin6->sin6_port)        & 0xff);
527	    }
528	    break;
529	default:
530	    e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
531	    goto ouch;
532	}
533	if (e != FTP_OK)
534	    goto ouch;
535
536	/* seek to required offset */
537	if (offset)
538	    if (_ftp_cmd(cd, "REST %lu", (u_long)offset) != FTP_FILE_OK)
539		goto sysouch;
540
541	/* make the server initiate the transfer */
542	if (verbose)
543	    _fetch_info("initiating transfer");
544	e = _ftp_cmd(cd, "%s %s", oper, _ftp_filename(file));
545	if (e != FTP_OPEN_DATA_CONNECTION)
546	    goto ouch;
547
548	/* accept the incoming connection and go to town */
549	if ((d = accept(sd, NULL, NULL)) == -1)
550	    goto sysouch;
551	close(sd);
552	sd = d;
553    }
554
555    if ((df = fdopen(sd, mode)) == NULL)
556	goto sysouch;
557    return df;
558
559sysouch:
560    _fetch_syserr();
561    if (sd >= 0)
562	close(sd);
563    return NULL;
564
565ouch:
566    if (e != -1)
567	_ftp_seterr(e);
568    if (sd >= 0)
569	close(sd);
570    return NULL;
571}
572
573/*
574 * Return default port
575 */
576static int
577_ftp_default_port(void)
578{
579    struct servent *se;
580
581    if ((se = getservbyname("ftp", "tcp")) != NULL)
582	return ntohs(se->s_port);
583    return FTP_DEFAULT_PORT;
584}
585
586/*
587 * Log on to FTP server
588 */
589static int
590_ftp_connect(char *host, int port, char *user, char *pwd, char *flags)
591{
592    int cd, e, pp = 0, direct, verbose;
593#ifdef INET6
594    int af = AF_UNSPEC;
595#else
596    int af = AF_INET;
597#endif
598    char *p, *q;
599    const char *logname;
600    char localhost[MAXHOSTNAMELEN];
601    char pbuf[MAXHOSTNAMELEN + MAXLOGNAME + 1];
602
603    direct = (flags && strchr(flags, 'd'));
604    verbose = (flags && strchr(flags, 'v'));
605    if ((flags && strchr(flags, '4')))
606	af = AF_INET;
607    else if ((flags && strchr(flags, '6')))
608	af = AF_INET6;
609
610    /* check for proxy */
611    if (!direct && (p = getenv("FTP_PROXY")) != NULL && *p) {
612	char c = 0;
613
614#ifdef INET6
615	if (*p != '[' || (q = strchr(p + 1, ']')) == NULL ||
616	    (*++q != '\0' && *q != ':'))
617#endif
618	    q = strchr(p, ':');
619	if (q != NULL && *q == ':') {
620	    if (strspn(q+1, "0123456789") != strlen(q+1) || strlen(q+1) > 5) {
621		/* XXX we should emit some kind of warning */
622	    }
623	    pp = atoi(q+1);
624	    if (pp < 1 || pp > 65535) {
625		/* XXX we should emit some kind of warning */
626	    }
627	}
628	if (!pp)
629	    pp = _ftp_default_port();
630	if (q) {
631#ifdef INET6
632	    if (q > p && *p == '[' && *(q - 1) == ']') {
633		p++;
634		q--;
635	    }
636#endif
637	    c = *q;
638	    *q = 0;
639	}
640	cd = _fetch_connect(p, pp, af, verbose);
641	if (q)
642	    *q = c;
643    } else {
644	/* no proxy, go straight to target */
645	cd = _fetch_connect(host, port, af, verbose);
646	p = NULL;
647    }
648
649    /* check connection */
650    if (cd == -1) {
651	_fetch_syserr();
652	return NULL;
653    }
654
655    /* expect welcome message */
656    if ((e = _ftp_chkerr(cd)) != FTP_SERVICE_READY)
657	goto fouch;
658
659    /* send user name and password */
660    if (!user || !*user)
661	user = FTP_ANONYMOUS_USER;
662    if (p && port == FTP_DEFAULT_PORT)
663	e = _ftp_cmd(cd, "USER %s@%s", user, host);
664    else if (p)
665	e = _ftp_cmd(cd, "USER %s@%s@%d", user, host, port);
666    else
667	e = _ftp_cmd(cd, "USER %s", user);
668
669    /* did the server request a password? */
670    if (e == FTP_NEED_PASSWORD) {
671	if (!pwd || !*pwd)
672	    pwd = getenv("FTP_PASSWORD");
673	if (!pwd || !*pwd) {
674	    if ((logname = getlogin()) == 0)
675		logname = FTP_ANONYMOUS_PASSWORD;
676	    gethostname(localhost, sizeof localhost);
677	    snprintf(pbuf, sizeof pbuf, "%s@%s", logname, localhost);
678	    pwd = pbuf;
679	}
680	e = _ftp_cmd(cd, "PASS %s", pwd);
681    }
682
683    /* did the server request an account? */
684    if (e == FTP_NEED_ACCOUNT)
685	goto fouch;
686
687    /* we should be done by now */
688    if (e != FTP_LOGGED_IN)
689	goto fouch;
690
691    /* might as well select mode and type at once */
692#ifdef FTP_FORCE_STREAM_MODE
693    if ((e = _ftp_cmd(cd, "MODE S")) != FTP_OK) /* default is S */
694	goto fouch;
695#endif
696    if ((e = _ftp_cmd(cd, "TYPE I")) != FTP_OK) /* default is A */
697	goto fouch;
698
699    /* done */
700    return cd;
701
702fouch:
703    if (e != -1)
704	_ftp_seterr(e);
705    close(cd);
706    return NULL;
707}
708
709/*
710 * Disconnect from server
711 */
712static void
713_ftp_disconnect(int cd)
714{
715    (void)_ftp_cmd(cd, "QUIT");
716    close(cd);
717}
718
719/*
720 * Check if we're already connected
721 */
722static int
723_ftp_isconnected(struct url *url)
724{
725    return (cached_socket
726	    && (strcmp(url->host, cached_host.host) == 0)
727	    && (strcmp(url->user, cached_host.user) == 0)
728	    && (strcmp(url->pwd, cached_host.pwd) == 0)
729	    && (url->port == cached_host.port));
730}
731
732/*
733 * Check the cache, reconnect if no luck
734 */
735static int
736_ftp_cached_connect(struct url *url, char *flags)
737{
738    int e, cd;
739
740    cd = -1;
741
742    /* set default port */
743    if (!url->port)
744	url->port = _ftp_default_port();
745
746    /* try to use previously cached connection */
747    if (_ftp_isconnected(url)) {
748	e = _ftp_cmd(cached_socket, "NOOP");
749	if (e == FTP_OK || e == FTP_SYNTAX_ERROR)
750	    cd = cached_socket;
751    }
752
753    /* connect to server */
754    if (cd == -1) {
755	cd = _ftp_connect(url->host, url->port, url->user, url->pwd, flags);
756	if (cd == -1)
757	    return -1;
758	if (cached_socket)
759	    _ftp_disconnect(cached_socket);
760	cached_socket = cd;
761	memcpy(&cached_host, url, sizeof *url);
762    }
763
764    return cd;
765}
766
767/*
768 * Check to see if we should use an HTTP proxy instead
769 */
770static int
771_ftp_use_http_proxy(void)
772{
773    char *p;
774
775    return ((p = getenv("HTTP_PROXY")) && *p && !getenv("FTP_PROXY"));
776}
777
778/*
779 * Get and stat file
780 */
781FILE *
782fetchXGetFTP(struct url *url, struct url_stat *us, char *flags)
783{
784    int cd;
785
786    if (_ftp_use_http_proxy())
787	return fetchXGetHTTP(url, us, flags);
788
789    /* connect to server */
790    if ((cd = _ftp_cached_connect(url, flags)) == NULL)
791	return NULL;
792
793    /* change directory */
794    if (_ftp_cwd(cd, url->doc) == -1)
795	return NULL;
796
797    /* stat file */
798    if (us && _ftp_stat(cd, url->doc, us) == -1
799	&& fetchLastErrCode != FETCH_PROTO
800	&& fetchLastErrCode != FETCH_UNAVAIL)
801	return NULL;
802
803    /* initiate the transfer */
804    return _ftp_transfer(cd, "RETR", url->doc, "r", url->offset, flags);
805}
806
807/*
808 * Get file
809 */
810FILE *
811fetchGetFTP(struct url *url, char *flags)
812{
813    return fetchXGetFTP(url, NULL, flags);
814}
815
816/*
817 * Put file
818 */
819FILE *
820fetchPutFTP(struct url *url, char *flags)
821{
822    int cd;
823
824    if (_ftp_use_http_proxy())
825	return fetchPutHTTP(url, flags);
826
827    /* connect to server */
828    if ((cd = _ftp_cached_connect(url, flags)) == NULL)
829	return NULL;
830
831    /* change directory */
832    if (_ftp_cwd(cd, url->doc) == -1)
833	return NULL;
834
835    /* initiate the transfer */
836    return _ftp_transfer(cd, (flags && strchr(flags, 'a')) ? "APPE" : "STOR",
837			 url->doc, "w", url->offset, flags);
838}
839
840/*
841 * Get file stats
842 */
843int
844fetchStatFTP(struct url *url, struct url_stat *us, char *flags)
845{
846    int cd;
847
848    if (_ftp_use_http_proxy())
849	return fetchStatHTTP(url, us, flags);
850
851    /* connect to server */
852    if ((cd = _ftp_cached_connect(url, flags)) == NULL)
853	return -1;
854
855    /* change directory */
856    if (_ftp_cwd(cd, url->doc) == -1)
857	return -1;
858
859    /* stat file */
860    return _ftp_stat(cd, url->doc, us);
861}
862
863/*
864 * List a directory
865 */
866extern void warnx(char *, ...);
867struct url_ent *
868fetchListFTP(struct url *url, char *flags)
869{
870    if (_ftp_use_http_proxy())
871	return fetchListHTTP(url, flags);
872
873    warnx("fetchListFTP(): not implemented");
874    return NULL;
875}
876