ftp.c revision 74716 
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 74716 2001-03-24 00:28:57Z 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	"anonymous"
78
79#define FTP_CONNECTION_ALREADY_OPEN	125
80#define FTP_OPEN_DATA_CONNECTION	150
81#define FTP_OK				200
82#define FTP_FILE_STATUS			213
83#define FTP_SERVICE_READY		220
84#define FTP_TRANSFER_COMPLETE		226
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 (lr_length && !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 == NULL) {
331	errno = EBADF;
332	return -1;
333    }
334    if (io->csd == -1 || io->dsd == -1 || io->dir == O_WRONLY) {
335	errno = EBADF;
336	return -1;
337    }
338    if (io->err) {
339	errno = io->err;
340	return -1;
341    }
342    if (io->eof)
343	return 0;
344    r = read(io->dsd, buf, len);
345    if (r > 0)
346	return r;
347    if (r == 0) {
348	io->eof = 1;
349	return _ftp_closefn(v);
350    }
351    if (errno != EINTR)
352	io->err = errno;
353    return -1;
354}
355
356static int
357_ftp_writefn(void *v, const char *buf, int len)
358{
359    struct ftpio *io;
360    int w;
361
362    io = (struct ftpio *)v;
363    if (io == NULL) {
364	errno = EBADF;
365	return -1;
366    }
367    if (io->csd == -1 || io->dsd == -1 || io->dir == O_RDONLY) {
368	errno = EBADF;
369	return -1;
370    }
371    if (io->err) {
372	errno = io->err;
373	return -1;
374    }
375    w = write(io->dsd, buf, len);
376    if (w >= 0)
377	return w;
378    if (errno != EINTR)
379	io->err = errno;
380    return -1;
381}
382
383static fpos_t
384_ftp_seekfn(void *v, fpos_t pos, int whence)
385{
386    struct ftpio *io;
387
388    io = (struct ftpio *)v;
389    if (io == NULL) {
390	errno = EBADF;
391	return -1;
392    }
393    errno = ESPIPE;
394    return -1;
395}
396
397static int
398_ftp_closefn(void *v)
399{
400    struct ftpio *io;
401    int r;
402
403    io = (struct ftpio *)v;
404    if (io == NULL) {
405	errno = EBADF;
406	return -1;
407    }
408    if (io->dir == -1)
409	return 0;
410    if (io->csd == -1 || io->dsd == -1) {
411	errno = EBADF;
412	return -1;
413    }
414    close(io->dsd);
415    io->dir = -1;
416    io->dsd = -1;
417    DEBUG(fprintf(stderr, "Waiting for final status\n"));
418    if ((r = _ftp_chkerr(io->csd)) != FTP_TRANSFER_COMPLETE)
419	io->err = r;
420    else
421	io->err = 0;
422    close(io->csd);
423    io->csd = -1;
424    return io->err ? -1 : 0;
425}
426
427static FILE *
428_ftp_setup(int csd, int dsd, int mode)
429{
430    struct ftpio *io;
431    FILE *f;
432
433    if ((io = malloc(sizeof *io)) == NULL)
434	return NULL;
435    io->csd = dup(csd);
436    io->dsd = dsd;
437    io->dir = mode;
438    io->eof = io->err = 0;
439    f = funopen(io, _ftp_readfn, _ftp_writefn, _ftp_seekfn, _ftp_closefn);
440    if (f == NULL)
441	free(io);
442    return f;
443}
444
445/*
446 * Transfer file
447 */
448static FILE *
449_ftp_transfer(int cd, char *oper, char *file,
450	      int mode, off_t offset, char *flags)
451{
452    struct sockaddr_storage sin;
453    struct sockaddr_in6 *sin6;
454    struct sockaddr_in *sin4;
455    int low, pasv, verbose;
456    int e, sd = -1;
457    socklen_t l;
458    char *s;
459    FILE *df;
460
461    /* check flags */
462    low = CHECK_FLAG('l');
463    pasv = CHECK_FLAG('p');
464    verbose = CHECK_FLAG('v');
465
466    /* passive mode */
467    if (!pasv)
468	pasv = ((s = getenv("FTP_PASSIVE_MODE")) != NULL &&
469		strncasecmp(s, "no", 2) != 0);
470
471    /* find our own address, bind, and listen */
472    l = sizeof sin;
473    if (getsockname(cd, (struct sockaddr *)&sin, &l) == -1)
474	goto sysouch;
475    if (sin.ss_family == AF_INET6)
476	unmappedaddr((struct sockaddr_in6 *)&sin);
477
478    /* open data socket */
479    if ((sd = socket(sin.ss_family, SOCK_STREAM, IPPROTO_TCP)) == -1) {
480	_fetch_syserr();
481	return NULL;
482    }
483
484    if (pasv) {
485	u_char addr[64];
486	char *ln, *p;
487	int i;
488	int port;
489
490	/* send PASV command */
491	if (verbose)
492	    _fetch_info("setting passive mode");
493	switch (sin.ss_family) {
494	case AF_INET:
495	    if ((e = _ftp_cmd(cd, "PASV")) != FTP_PASSIVE_MODE)
496		goto ouch;
497	    break;
498	case AF_INET6:
499	    if ((e = _ftp_cmd(cd, "EPSV")) != FTP_EPASSIVE_MODE) {
500		if (e == -1)
501		    goto ouch;
502		if ((e = _ftp_cmd(cd, "LPSV")) != FTP_LPASSIVE_MODE)
503		    goto ouch;
504	    }
505	    break;
506	default:
507	    e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
508	    goto ouch;
509	}
510
511	/*
512	 * Find address and port number. The reply to the PASV command
513         * is IMHO the one and only weak point in the FTP protocol.
514	 */
515	ln = last_reply;
516      	switch (e) {
517	case FTP_PASSIVE_MODE:
518	case FTP_LPASSIVE_MODE:
519	    for (p = ln + 3; *p && !isdigit(*p); p++)
520		/* nothing */ ;
521	    if (!*p) {
522		e = FTP_PROTOCOL_ERROR;
523		goto ouch;
524	    }
525	    l = (e == FTP_PASSIVE_MODE ? 6 : 21);
526	    for (i = 0; *p && i < l; i++, p++)
527		addr[i] = strtol(p, &p, 10);
528	    if (i < l) {
529		e = FTP_PROTOCOL_ERROR;
530		goto ouch;
531	    }
532	    break;
533	case FTP_EPASSIVE_MODE:
534	    for (p = ln + 3; *p && *p != '('; p++)
535		/* nothing */ ;
536	    if (!*p) {
537		e = FTP_PROTOCOL_ERROR;
538		goto ouch;
539	    }
540	    ++p;
541	    if (sscanf(p, "%c%c%c%d%c", &addr[0], &addr[1], &addr[2],
542		       &port, &addr[3]) != 5 ||
543		addr[0] != addr[1] ||
544		addr[0] != addr[2] || addr[0] != addr[3]) {
545		e = FTP_PROTOCOL_ERROR;
546		goto ouch;
547	    }
548	    break;
549	}
550
551	/* seek to required offset */
552	if (offset)
553	    if (_ftp_cmd(cd, "REST %lu", (u_long)offset) != FTP_FILE_OK)
554		goto sysouch;
555
556	/* construct sockaddr for data socket */
557	l = sizeof sin;
558	if (getpeername(cd, (struct sockaddr *)&sin, &l) == -1)
559	    goto sysouch;
560	if (sin.ss_family == AF_INET6)
561	    unmappedaddr((struct sockaddr_in6 *)&sin);
562	switch (sin.ss_family) {
563	case AF_INET6:
564	    sin6 = (struct sockaddr_in6 *)&sin;
565	    if (e == FTP_EPASSIVE_MODE)
566		sin6->sin6_port = htons(port);
567	    else {
568		bcopy(addr + 2, (char *)&sin6->sin6_addr, 16);
569		bcopy(addr + 19, (char *)&sin6->sin6_port, 2);
570	    }
571	    break;
572	case AF_INET:
573	    sin4 = (struct sockaddr_in *)&sin;
574	    if (e == FTP_EPASSIVE_MODE)
575		sin4->sin_port = htons(port);
576	    else {
577		bcopy(addr, (char *)&sin4->sin_addr, 4);
578		bcopy(addr + 4, (char *)&sin4->sin_port, 2);
579	    }
580	    break;
581	default:
582	    e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
583	    break;
584	}
585
586	/* connect to data port */
587	if (verbose)
588	    _fetch_info("opening data connection");
589	if (connect(sd, (struct sockaddr *)&sin, sin.ss_len) == -1)
590	    goto sysouch;
591
592	/* make the server initiate the transfer */
593	if (verbose)
594	    _fetch_info("initiating transfer");
595	e = _ftp_cmd(cd, "%s %s", oper, _ftp_filename(file));
596	if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
597	    goto ouch;
598
599    } else {
600	u_int32_t a;
601	u_short p;
602	int arg, d;
603	char *ap;
604	char hname[INET6_ADDRSTRLEN];
605
606	switch (sin.ss_family) {
607	case AF_INET6:
608	    ((struct sockaddr_in6 *)&sin)->sin6_port = 0;
609#ifdef IPV6_PORTRANGE
610	    arg = low ? IPV6_PORTRANGE_DEFAULT : IPV6_PORTRANGE_HIGH;
611	    if (setsockopt(sd, IPPROTO_IPV6, IPV6_PORTRANGE,
612			   (char *)&arg, sizeof(arg)) == -1)
613		goto sysouch;
614#endif
615	    break;
616	case AF_INET:
617	    ((struct sockaddr_in *)&sin)->sin_port = 0;
618	    arg = low ? IP_PORTRANGE_DEFAULT : IP_PORTRANGE_HIGH;
619	    if (setsockopt(sd, IPPROTO_IP, IP_PORTRANGE,
620			   (char *)&arg, sizeof arg) == -1)
621		goto sysouch;
622	    break;
623	}
624	if (verbose)
625	    _fetch_info("binding data socket");
626	if (bind(sd, (struct sockaddr *)&sin, sin.ss_len) == -1)
627	    goto sysouch;
628	if (listen(sd, 1) == -1)
629	    goto sysouch;
630
631	/* find what port we're on and tell the server */
632	if (getsockname(sd, (struct sockaddr *)&sin, &l) == -1)
633	    goto sysouch;
634	switch (sin.ss_family) {
635	case AF_INET:
636	    sin4 = (struct sockaddr_in *)&sin;
637	    a = ntohl(sin4->sin_addr.s_addr);
638	    p = ntohs(sin4->sin_port);
639	    e = _ftp_cmd(cd, "PORT %d,%d,%d,%d,%d,%d",
640			 (a >> 24) & 0xff, (a >> 16) & 0xff,
641			 (a >> 8) & 0xff, a & 0xff,
642			 (p >> 8) & 0xff, p & 0xff);
643	    break;
644	case AF_INET6:
645#define UC(b)	(((int)b)&0xff)
646	    e = -1;
647	    sin6 = (struct sockaddr_in6 *)&sin;
648	    if (getnameinfo((struct sockaddr *)&sin, sin.ss_len,
649			    hname, sizeof(hname),
650			    NULL, 0, NI_NUMERICHOST) == 0) {
651		e = _ftp_cmd(cd, "EPRT |%d|%s|%d|", 2, hname,
652			     htons(sin6->sin6_port));
653		if (e == -1)
654		    goto ouch;
655	    }
656	    if (e != FTP_OK) {
657		ap = (char *)&sin6->sin6_addr;
658		e = _ftp_cmd(cd,
659     "LPRT %d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d",
660			     6, 16,
661			     UC(ap[0]), UC(ap[1]), UC(ap[2]), UC(ap[3]),
662			     UC(ap[4]), UC(ap[5]), UC(ap[6]), UC(ap[7]),
663			     UC(ap[8]), UC(ap[9]), UC(ap[10]), UC(ap[11]),
664			     UC(ap[12]), UC(ap[13]), UC(ap[14]), UC(ap[15]),
665			     2,
666			     (ntohs(sin6->sin6_port) >> 8) & 0xff,
667			     ntohs(sin6->sin6_port)        & 0xff);
668	    }
669	    break;
670	default:
671	    e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
672	    goto ouch;
673	}
674	if (e != FTP_OK)
675	    goto ouch;
676
677	/* seek to required offset */
678	if (offset)
679	    if (_ftp_cmd(cd, "REST %lu", (u_long)offset) != FTP_FILE_OK)
680		goto sysouch;
681
682	/* make the server initiate the transfer */
683	if (verbose)
684	    _fetch_info("initiating transfer");
685	e = _ftp_cmd(cd, "%s %s", oper, _ftp_filename(file));
686	if (e != FTP_OPEN_DATA_CONNECTION)
687	    goto ouch;
688
689	/* accept the incoming connection and go to town */
690	if ((d = accept(sd, NULL, NULL)) == -1)
691	    goto sysouch;
692	close(sd);
693	sd = d;
694    }
695
696    if ((df = _ftp_setup(cd, sd, mode)) == NULL)
697	goto sysouch;
698    return df;
699
700sysouch:
701    _fetch_syserr();
702    if (sd >= 0)
703	close(sd);
704    return NULL;
705
706ouch:
707    if (e != -1)
708	_ftp_seterr(e);
709    if (sd >= 0)
710	close(sd);
711    return NULL;
712}
713
714/*
715 * Log on to FTP server
716 */
717static int
718_ftp_connect(struct url *url, struct url *purl, char *flags)
719{
720    int cd, e, direct, verbose;
721#ifdef INET6
722    int af = AF_UNSPEC;
723#else
724    int af = AF_INET;
725#endif
726    const char *logname;
727    char *user, *pwd;
728    char localhost[MAXHOSTNAMELEN];
729    char pbuf[MAXHOSTNAMELEN + MAXLOGNAME + 1];
730
731    direct = CHECK_FLAG('d');
732    verbose = CHECK_FLAG('v');
733    if (CHECK_FLAG('4'))
734	af = AF_INET;
735    else if (CHECK_FLAG('6'))
736	af = AF_INET6;
737
738    if (direct)
739	purl = NULL;
740
741    /* check for proxy */
742    if (purl) {
743	/* XXX proxy authentication! */
744	cd = _fetch_connect(purl->host, purl->port, af, verbose);
745    } else {
746	/* no proxy, go straight to target */
747	cd = _fetch_connect(url->host, url->port, af, verbose);
748	purl = NULL;
749    }
750
751    /* check connection */
752    if (cd == -1) {
753	_fetch_syserr();
754	return NULL;
755    }
756
757    /* expect welcome message */
758    if ((e = _ftp_chkerr(cd)) != FTP_SERVICE_READY)
759	goto fouch;
760
761    /* XXX FTP_AUTH, and maybe .netrc */
762
763    /* send user name and password */
764    user = url->user;
765    if (!user || !*user)
766	user = getenv("FTP_LOGIN");
767    if (!user || !*user)
768	user = FTP_ANONYMOUS_USER;
769    if (purl && url->port == _fetch_default_port(url->scheme))
770	e = _ftp_cmd(cd, "USER %s@%s", user, url->host);
771    else if (purl)
772	e = _ftp_cmd(cd, "USER %s@%s@%d", user, url->host, url->port);
773    else
774	e = _ftp_cmd(cd, "USER %s", user);
775
776    /* did the server request a password? */
777    if (e == FTP_NEED_PASSWORD) {
778	pwd = url->pwd;
779	if (!pwd || !*pwd)
780	    pwd = getenv("FTP_PASSWORD");
781	if (!pwd || !*pwd) {
782	    if ((logname = getlogin()) == 0)
783		logname = FTP_ANONYMOUS_USER;
784	    gethostname(localhost, sizeof localhost);
785	    snprintf(pbuf, sizeof pbuf, "%s@%s", logname, localhost);
786	    pwd = pbuf;
787	}
788	e = _ftp_cmd(cd, "PASS %s", pwd);
789    }
790
791    /* did the server request an account? */
792    if (e == FTP_NEED_ACCOUNT)
793	goto fouch;
794
795    /* we should be done by now */
796    if (e != FTP_LOGGED_IN)
797	goto fouch;
798
799    /* might as well select mode and type at once */
800#ifdef FTP_FORCE_STREAM_MODE
801    if ((e = _ftp_cmd(cd, "MODE S")) != FTP_OK) /* default is S */
802	goto fouch;
803#endif
804    if ((e = _ftp_cmd(cd, "TYPE I")) != FTP_OK) /* default is A */
805	goto fouch;
806
807    /* done */
808    return cd;
809
810fouch:
811    if (e != -1)
812	_ftp_seterr(e);
813    close(cd);
814    return NULL;
815}
816
817/*
818 * Disconnect from server
819 */
820static void
821_ftp_disconnect(int cd)
822{
823    (void)_ftp_cmd(cd, "QUIT");
824    close(cd);
825}
826
827/*
828 * Check if we're already connected
829 */
830static int
831_ftp_isconnected(struct url *url)
832{
833    return (cached_socket
834	    && (strcmp(url->host, cached_host.host) == 0)
835	    && (strcmp(url->user, cached_host.user) == 0)
836	    && (strcmp(url->pwd, cached_host.pwd) == 0)
837	    && (url->port == cached_host.port));
838}
839
840/*
841 * Check the cache, reconnect if no luck
842 */
843static int
844_ftp_cached_connect(struct url *url, struct url *purl, char *flags)
845{
846    int e, cd;
847
848    cd = -1;
849
850    /* set default port */
851    if (!url->port)
852	url->port = _fetch_default_port(url->scheme);
853
854    /* try to use previously cached connection */
855    if (_ftp_isconnected(url)) {
856	e = _ftp_cmd(cached_socket, "NOOP");
857	if (e == FTP_OK || e == FTP_SYNTAX_ERROR)
858	    return cached_socket;
859    }
860
861    /* connect to server */
862    if ((cd = _ftp_connect(url, purl, flags)) == -1)
863	return -1;
864    if (cached_socket)
865	_ftp_disconnect(cached_socket);
866    cached_socket = cd;
867    memcpy(&cached_host, url, sizeof *url);
868    return cd;
869}
870
871/*
872 * Check the proxy settings
873 */
874static struct url *
875_ftp_get_proxy(void)
876{
877    struct url *purl;
878    char *p;
879
880    if (((p = getenv("FTP_PROXY")) || (p = getenv("ftp_proxy")) ||
881	 (p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
882	*p && (purl = fetchParseURL(p)) != NULL) {
883	if (!*purl->scheme) {
884	    if (getenv("FTP_PROXY") || getenv("ftp_proxy"))
885		strcpy(purl->scheme, SCHEME_FTP);
886	    else
887		strcpy(purl->scheme, SCHEME_HTTP);
888	}
889	if (!purl->port)
890	    purl->port = _fetch_default_proxy_port(purl->scheme);
891	if (strcasecmp(purl->scheme, SCHEME_FTP) == 0 ||
892	    strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
893	    return purl;
894	fetchFreeURL(purl);
895    }
896    return NULL;
897}
898
899/*
900 * Get and stat file
901 */
902FILE *
903fetchXGetFTP(struct url *url, struct url_stat *us, char *flags)
904{
905    struct url *purl;
906    int cd;
907
908    /* get the proxy URL, and check if we should use HTTP instead */
909    if (!CHECK_FLAG('d') && (purl = _ftp_get_proxy()) != NULL) {
910	if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
911	    return _http_request(url, "GET", us, purl, flags);
912    } else {
913	purl = NULL;
914    }
915
916    /* connect to server */
917    cd = _ftp_cached_connect(url, purl, flags);
918    if (purl)
919	fetchFreeURL(purl);
920    if (cd == NULL)
921	return NULL;
922
923    /* change directory */
924    if (_ftp_cwd(cd, url->doc) == -1)
925	return NULL;
926
927    /* stat file */
928    if (us && _ftp_stat(cd, url->doc, us) == -1
929	&& fetchLastErrCode != FETCH_PROTO
930	&& fetchLastErrCode != FETCH_UNAVAIL)
931	return NULL;
932
933    /* initiate the transfer */
934    return _ftp_transfer(cd, "RETR", url->doc, O_RDONLY, url->offset, flags);
935}
936
937/*
938 * Get file
939 */
940FILE *
941fetchGetFTP(struct url *url, char *flags)
942{
943    return fetchXGetFTP(url, NULL, flags);
944}
945
946/*
947 * Put file
948 */
949FILE *
950fetchPutFTP(struct url *url, char *flags)
951{
952    struct url *purl;
953    int cd;
954
955    /* get the proxy URL, and check if we should use HTTP instead */
956    if (!CHECK_FLAG('d') && (purl = _ftp_get_proxy()) != NULL) {
957	if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
958	    /* XXX HTTP PUT is not implemented, so try without the proxy */
959	    purl = NULL;
960    } else {
961	purl = NULL;
962    }
963
964    /* connect to server */
965    cd = _ftp_cached_connect(url, purl, flags);
966    if (purl)
967	fetchFreeURL(purl);
968    if (cd == NULL)
969	return NULL;
970
971    /* change directory */
972    if (_ftp_cwd(cd, url->doc) == -1)
973	return NULL;
974
975    /* initiate the transfer */
976    return _ftp_transfer(cd, CHECK_FLAG('a') ? "APPE" : "STOR",
977			 url->doc, O_WRONLY, url->offset, flags);
978}
979
980/*
981 * Get file stats
982 */
983int
984fetchStatFTP(struct url *url, struct url_stat *us, char *flags)
985{
986    struct url *purl;
987    int cd;
988
989    /* get the proxy URL, and check if we should use HTTP instead */
990    if (!CHECK_FLAG('d') && (purl = _ftp_get_proxy()) != NULL) {
991	if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0) {
992	    FILE *f;
993
994	    if ((f = _http_request(url, "HEAD", us, purl, flags)) == NULL)
995		return -1;
996	    fclose(f);
997	    return 0;
998	}
999    } else {
1000	purl = NULL;
1001    }
1002
1003    /* connect to server */
1004    cd = _ftp_cached_connect(url, purl, flags);
1005    if (purl)
1006	fetchFreeURL(purl);
1007    if (cd == NULL)
1008	return NULL;
1009
1010    /* change directory */
1011    if (_ftp_cwd(cd, url->doc) == -1)
1012	return -1;
1013
1014    /* stat file */
1015    return _ftp_stat(cd, url->doc, us);
1016}
1017
1018/*
1019 * List a directory
1020 */
1021extern void warnx(char *, ...);
1022struct url_ent *
1023fetchListFTP(struct url *url, char *flags)
1024{
1025    warnx("fetchListFTP(): not implemented");
1026    return NULL;
1027}
1028