ftp.c revision 75292 
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 75292 2001-04-07 15:26:31Z 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	us->size = -1;
263	return -1;
264    }
265    if (us->size == 0)
266	us->size = -1;
267    DEBUG(fprintf(stderr, "size: [\033[1m%lld\033[m]\n", us->size));
268
269    if ((e = _ftp_cmd(cd, "MDTM %s", s)) != FTP_FILE_STATUS) {
270	_ftp_seterr(e);
271	return -1;
272    }
273    for (ln = last_reply + 4; *ln && isspace(*ln); ln++)
274	/* nothing */ ;
275    switch (strspn(ln, "0123456789")) {
276    case 14:
277	break;
278    case 15:
279	ln++;
280	ln[0] = '2';
281	ln[1] = '0';
282	break;
283    default:
284	_ftp_seterr(FTP_PROTOCOL_ERROR);
285	return -1;
286    }
287    if (sscanf(ln, "%04d%02d%02d%02d%02d%02d",
288	       &tm.tm_year, &tm.tm_mon, &tm.tm_mday,
289	       &tm.tm_hour, &tm.tm_min, &tm.tm_sec) != 6) {
290	_ftp_seterr(FTP_PROTOCOL_ERROR);
291	return -1;
292    }
293    tm.tm_mon--;
294    tm.tm_year -= 1900;
295    tm.tm_isdst = -1;
296    t = timegm(&tm);
297    if (t == (time_t)-1)
298	t = time(NULL);
299    us->mtime = t;
300    us->atime = t;
301    DEBUG(fprintf(stderr, "last modified: [\033[1m%04d-%02d-%02d "
302		  "%02d:%02d:%02d\033[m]\n",
303		  tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
304		  tm.tm_hour, tm.tm_min, tm.tm_sec));
305    return 0;
306}
307
308/*
309 * I/O functions for FTP
310 */
311struct ftpio {
312    int		 csd;		/* Control socket descriptor */
313    int		 dsd;		/* Data socket descriptor */
314    int		 dir;		/* Direction */
315    int		 eof;		/* EOF reached */
316    int		 err;		/* Error code */
317};
318
319static int	_ftp_readfn(void *, char *, int);
320static int	_ftp_writefn(void *, const char *, int);
321static fpos_t	_ftp_seekfn(void *, fpos_t, int);
322static int	_ftp_closefn(void *);
323
324static int
325_ftp_readfn(void *v, char *buf, int len)
326{
327    struct ftpio *io;
328    int r;
329
330    io = (struct ftpio *)v;
331    if (io == NULL) {
332	errno = EBADF;
333	return -1;
334    }
335    if (io->csd == -1 || io->dsd == -1 || io->dir == O_WRONLY) {
336	errno = EBADF;
337	return -1;
338    }
339    if (io->err) {
340	errno = io->err;
341	return -1;
342    }
343    if (io->eof)
344	return 0;
345    r = read(io->dsd, buf, len);
346    if (r > 0)
347	return r;
348    if (r == 0) {
349	io->eof = 1;
350	return _ftp_closefn(v);
351    }
352    if (errno != EINTR)
353	io->err = errno;
354    return -1;
355}
356
357static int
358_ftp_writefn(void *v, const char *buf, int len)
359{
360    struct ftpio *io;
361    int w;
362
363    io = (struct ftpio *)v;
364    if (io == NULL) {
365	errno = EBADF;
366	return -1;
367    }
368    if (io->csd == -1 || io->dsd == -1 || io->dir == O_RDONLY) {
369	errno = EBADF;
370	return -1;
371    }
372    if (io->err) {
373	errno = io->err;
374	return -1;
375    }
376    w = write(io->dsd, buf, len);
377    if (w >= 0)
378	return w;
379    if (errno != EINTR)
380	io->err = errno;
381    return -1;
382}
383
384static fpos_t
385_ftp_seekfn(void *v, fpos_t pos, int whence)
386{
387    struct ftpio *io;
388
389    io = (struct ftpio *)v;
390    if (io == NULL) {
391	errno = EBADF;
392	return -1;
393    }
394    errno = ESPIPE;
395    return -1;
396}
397
398static int
399_ftp_closefn(void *v)
400{
401    struct ftpio *io;
402    int r;
403
404    io = (struct ftpio *)v;
405    if (io == NULL) {
406	errno = EBADF;
407	return -1;
408    }
409    if (io->dir == -1)
410	return 0;
411    if (io->csd == -1 || io->dsd == -1) {
412	errno = EBADF;
413	return -1;
414    }
415    close(io->dsd);
416    io->dir = -1;
417    io->dsd = -1;
418    DEBUG(fprintf(stderr, "Waiting for final status\n"));
419    if ((r = _ftp_chkerr(io->csd)) != FTP_TRANSFER_COMPLETE)
420	io->err = r;
421    else
422	io->err = 0;
423    close(io->csd);
424    io->csd = -1;
425    return io->err ? -1 : 0;
426}
427
428static FILE *
429_ftp_setup(int csd, int dsd, int mode)
430{
431    struct ftpio *io;
432    FILE *f;
433
434    if ((io = malloc(sizeof *io)) == NULL)
435	return NULL;
436    io->csd = dup(csd);
437    io->dsd = dsd;
438    io->dir = mode;
439    io->eof = io->err = 0;
440    f = funopen(io, _ftp_readfn, _ftp_writefn, _ftp_seekfn, _ftp_closefn);
441    if (f == NULL)
442	free(io);
443    return f;
444}
445
446/*
447 * Transfer file
448 */
449static FILE *
450_ftp_transfer(int cd, char *oper, char *file,
451	      int mode, off_t offset, char *flags)
452{
453    struct sockaddr_storage sin;
454    struct sockaddr_in6 *sin6;
455    struct sockaddr_in *sin4;
456    int low, pasv, verbose;
457    int e, sd = -1;
458    socklen_t l;
459    char *s;
460    FILE *df;
461
462    /* check flags */
463    low = CHECK_FLAG('l');
464    pasv = CHECK_FLAG('p');
465    verbose = CHECK_FLAG('v');
466
467    /* passive mode */
468    if (!pasv)
469	pasv = ((s = getenv("FTP_PASSIVE_MODE")) != NULL &&
470		strncasecmp(s, "no", 2) != 0);
471
472    /* find our own address, bind, and listen */
473    l = sizeof sin;
474    if (getsockname(cd, (struct sockaddr *)&sin, &l) == -1)
475	goto sysouch;
476    if (sin.ss_family == AF_INET6)
477	unmappedaddr((struct sockaddr_in6 *)&sin);
478
479    /* open data socket */
480    if ((sd = socket(sin.ss_family, SOCK_STREAM, IPPROTO_TCP)) == -1) {
481	_fetch_syserr();
482	return NULL;
483    }
484
485    if (pasv) {
486	u_char addr[64];
487	char *ln, *p;
488	int i;
489	int port;
490
491	/* send PASV command */
492	if (verbose)
493	    _fetch_info("setting passive mode");
494	switch (sin.ss_family) {
495	case AF_INET:
496	    if ((e = _ftp_cmd(cd, "PASV")) != FTP_PASSIVE_MODE)
497		goto ouch;
498	    break;
499	case AF_INET6:
500	    if ((e = _ftp_cmd(cd, "EPSV")) != FTP_EPASSIVE_MODE) {
501		if (e == -1)
502		    goto ouch;
503		if ((e = _ftp_cmd(cd, "LPSV")) != FTP_LPASSIVE_MODE)
504		    goto ouch;
505	    }
506	    break;
507	default:
508	    e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
509	    goto ouch;
510	}
511
512	/*
513	 * Find address and port number. The reply to the PASV command
514         * is IMHO the one and only weak point in the FTP protocol.
515	 */
516	ln = last_reply;
517      	switch (e) {
518	case FTP_PASSIVE_MODE:
519	case FTP_LPASSIVE_MODE:
520	    for (p = ln + 3; *p && !isdigit(*p); p++)
521		/* nothing */ ;
522	    if (!*p) {
523		e = FTP_PROTOCOL_ERROR;
524		goto ouch;
525	    }
526	    l = (e == FTP_PASSIVE_MODE ? 6 : 21);
527	    for (i = 0; *p && i < l; i++, p++)
528		addr[i] = strtol(p, &p, 10);
529	    if (i < l) {
530		e = FTP_PROTOCOL_ERROR;
531		goto ouch;
532	    }
533	    break;
534	case FTP_EPASSIVE_MODE:
535	    for (p = ln + 3; *p && *p != '('; p++)
536		/* nothing */ ;
537	    if (!*p) {
538		e = FTP_PROTOCOL_ERROR;
539		goto ouch;
540	    }
541	    ++p;
542	    if (sscanf(p, "%c%c%c%d%c", &addr[0], &addr[1], &addr[2],
543		       &port, &addr[3]) != 5 ||
544		addr[0] != addr[1] ||
545		addr[0] != addr[2] || addr[0] != addr[3]) {
546		e = FTP_PROTOCOL_ERROR;
547		goto ouch;
548	    }
549	    break;
550	}
551
552	/* seek to required offset */
553	if (offset)
554	    if (_ftp_cmd(cd, "REST %lu", (u_long)offset) != FTP_FILE_OK)
555		goto sysouch;
556
557	/* construct sockaddr for data socket */
558	l = sizeof sin;
559	if (getpeername(cd, (struct sockaddr *)&sin, &l) == -1)
560	    goto sysouch;
561	if (sin.ss_family == AF_INET6)
562	    unmappedaddr((struct sockaddr_in6 *)&sin);
563	switch (sin.ss_family) {
564	case AF_INET6:
565	    sin6 = (struct sockaddr_in6 *)&sin;
566	    if (e == FTP_EPASSIVE_MODE)
567		sin6->sin6_port = htons(port);
568	    else {
569		bcopy(addr + 2, (char *)&sin6->sin6_addr, 16);
570		bcopy(addr + 19, (char *)&sin6->sin6_port, 2);
571	    }
572	    break;
573	case AF_INET:
574	    sin4 = (struct sockaddr_in *)&sin;
575	    if (e == FTP_EPASSIVE_MODE)
576		sin4->sin_port = htons(port);
577	    else {
578		bcopy(addr, (char *)&sin4->sin_addr, 4);
579		bcopy(addr + 4, (char *)&sin4->sin_port, 2);
580	    }
581	    break;
582	default:
583	    e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
584	    break;
585	}
586
587	/* connect to data port */
588	if (verbose)
589	    _fetch_info("opening data connection");
590	if (connect(sd, (struct sockaddr *)&sin, sin.ss_len) == -1)
591	    goto sysouch;
592
593	/* make the server initiate the transfer */
594	if (verbose)
595	    _fetch_info("initiating transfer");
596	e = _ftp_cmd(cd, "%s %s", oper, _ftp_filename(file));
597	if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
598	    goto ouch;
599
600    } else {
601	u_int32_t a;
602	u_short p;
603	int arg, d;
604	char *ap;
605	char hname[INET6_ADDRSTRLEN];
606
607	switch (sin.ss_family) {
608	case AF_INET6:
609	    ((struct sockaddr_in6 *)&sin)->sin6_port = 0;
610#ifdef IPV6_PORTRANGE
611	    arg = low ? IPV6_PORTRANGE_DEFAULT : IPV6_PORTRANGE_HIGH;
612	    if (setsockopt(sd, IPPROTO_IPV6, IPV6_PORTRANGE,
613			   (char *)&arg, sizeof(arg)) == -1)
614		goto sysouch;
615#endif
616	    break;
617	case AF_INET:
618	    ((struct sockaddr_in *)&sin)->sin_port = 0;
619	    arg = low ? IP_PORTRANGE_DEFAULT : IP_PORTRANGE_HIGH;
620	    if (setsockopt(sd, IPPROTO_IP, IP_PORTRANGE,
621			   (char *)&arg, sizeof arg) == -1)
622		goto sysouch;
623	    break;
624	}
625	if (verbose)
626	    _fetch_info("binding data socket");
627	if (bind(sd, (struct sockaddr *)&sin, sin.ss_len) == -1)
628	    goto sysouch;
629	if (listen(sd, 1) == -1)
630	    goto sysouch;
631
632	/* find what port we're on and tell the server */
633	if (getsockname(sd, (struct sockaddr *)&sin, &l) == -1)
634	    goto sysouch;
635	switch (sin.ss_family) {
636	case AF_INET:
637	    sin4 = (struct sockaddr_in *)&sin;
638	    a = ntohl(sin4->sin_addr.s_addr);
639	    p = ntohs(sin4->sin_port);
640	    e = _ftp_cmd(cd, "PORT %d,%d,%d,%d,%d,%d",
641			 (a >> 24) & 0xff, (a >> 16) & 0xff,
642			 (a >> 8) & 0xff, a & 0xff,
643			 (p >> 8) & 0xff, p & 0xff);
644	    break;
645	case AF_INET6:
646#define UC(b)	(((int)b)&0xff)
647	    e = -1;
648	    sin6 = (struct sockaddr_in6 *)&sin;
649	    if (getnameinfo((struct sockaddr *)&sin, sin.ss_len,
650			    hname, sizeof(hname),
651			    NULL, 0, NI_NUMERICHOST) == 0) {
652		e = _ftp_cmd(cd, "EPRT |%d|%s|%d|", 2, hname,
653			     htons(sin6->sin6_port));
654		if (e == -1)
655		    goto ouch;
656	    }
657	    if (e != FTP_OK) {
658		ap = (char *)&sin6->sin6_addr;
659		e = _ftp_cmd(cd,
660     "LPRT %d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d",
661			     6, 16,
662			     UC(ap[0]), UC(ap[1]), UC(ap[2]), UC(ap[3]),
663			     UC(ap[4]), UC(ap[5]), UC(ap[6]), UC(ap[7]),
664			     UC(ap[8]), UC(ap[9]), UC(ap[10]), UC(ap[11]),
665			     UC(ap[12]), UC(ap[13]), UC(ap[14]), UC(ap[15]),
666			     2,
667			     (ntohs(sin6->sin6_port) >> 8) & 0xff,
668			     ntohs(sin6->sin6_port)        & 0xff);
669	    }
670	    break;
671	default:
672	    e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
673	    goto ouch;
674	}
675	if (e != FTP_OK)
676	    goto ouch;
677
678	/* seek to required offset */
679	if (offset)
680	    if (_ftp_cmd(cd, "REST %lu", (u_long)offset) != FTP_FILE_OK)
681		goto sysouch;
682
683	/* make the server initiate the transfer */
684	if (verbose)
685	    _fetch_info("initiating transfer");
686	e = _ftp_cmd(cd, "%s %s", oper, _ftp_filename(file));
687	if (e != FTP_OPEN_DATA_CONNECTION)
688	    goto ouch;
689
690	/* accept the incoming connection and go to town */
691	if ((d = accept(sd, NULL, NULL)) == -1)
692	    goto sysouch;
693	close(sd);
694	sd = d;
695    }
696
697    if ((df = _ftp_setup(cd, sd, mode)) == NULL)
698	goto sysouch;
699    return df;
700
701sysouch:
702    _fetch_syserr();
703    if (sd >= 0)
704	close(sd);
705    return NULL;
706
707ouch:
708    if (e != -1)
709	_ftp_seterr(e);
710    if (sd >= 0)
711	close(sd);
712    return NULL;
713}
714
715/*
716 * Log on to FTP server
717 */
718static int
719_ftp_connect(struct url *url, struct url *purl, char *flags)
720{
721    int cd, e, direct, verbose;
722#ifdef INET6
723    int af = AF_UNSPEC;
724#else
725    int af = AF_INET;
726#endif
727    const char *logname;
728    char *user, *pwd;
729    char localhost[MAXHOSTNAMELEN];
730    char pbuf[MAXHOSTNAMELEN + MAXLOGNAME + 1];
731
732    direct = CHECK_FLAG('d');
733    verbose = CHECK_FLAG('v');
734    if (CHECK_FLAG('4'))
735	af = AF_INET;
736    else if (CHECK_FLAG('6'))
737	af = AF_INET6;
738
739    if (direct)
740	purl = NULL;
741
742    /* check for proxy */
743    if (purl) {
744	/* XXX proxy authentication! */
745	cd = _fetch_connect(purl->host, purl->port, af, verbose);
746    } else {
747	/* no proxy, go straight to target */
748	cd = _fetch_connect(url->host, url->port, af, verbose);
749	purl = NULL;
750    }
751
752    /* check connection */
753    if (cd == -1) {
754	_fetch_syserr();
755	return NULL;
756    }
757
758    /* expect welcome message */
759    if ((e = _ftp_chkerr(cd)) != FTP_SERVICE_READY)
760	goto fouch;
761
762    /* XXX FTP_AUTH, and maybe .netrc */
763
764    /* send user name and password */
765    user = url->user;
766    if (!user || !*user)
767	user = getenv("FTP_LOGIN");
768    if (!user || !*user)
769	user = FTP_ANONYMOUS_USER;
770    if (purl && url->port == _fetch_default_port(url->scheme))
771	e = _ftp_cmd(cd, "USER %s@%s", user, url->host);
772    else if (purl)
773	e = _ftp_cmd(cd, "USER %s@%s@%d", user, url->host, url->port);
774    else
775	e = _ftp_cmd(cd, "USER %s", user);
776
777    /* did the server request a password? */
778    if (e == FTP_NEED_PASSWORD) {
779	pwd = url->pwd;
780	if (!pwd || !*pwd)
781	    pwd = getenv("FTP_PASSWORD");
782	if (!pwd || !*pwd) {
783	    if ((logname = getlogin()) == 0)
784		logname = FTP_ANONYMOUS_USER;
785	    gethostname(localhost, sizeof localhost);
786	    snprintf(pbuf, sizeof pbuf, "%s@%s", logname, localhost);
787	    pwd = pbuf;
788	}
789	e = _ftp_cmd(cd, "PASS %s", pwd);
790    }
791
792    /* did the server request an account? */
793    if (e == FTP_NEED_ACCOUNT)
794	goto fouch;
795
796    /* we should be done by now */
797    if (e != FTP_LOGGED_IN)
798	goto fouch;
799
800    /* might as well select mode and type at once */
801#ifdef FTP_FORCE_STREAM_MODE
802    if ((e = _ftp_cmd(cd, "MODE S")) != FTP_OK) /* default is S */
803	goto fouch;
804#endif
805    if ((e = _ftp_cmd(cd, "TYPE I")) != FTP_OK) /* default is A */
806	goto fouch;
807
808    /* done */
809    return cd;
810
811fouch:
812    if (e != -1)
813	_ftp_seterr(e);
814    close(cd);
815    return NULL;
816}
817
818/*
819 * Disconnect from server
820 */
821static void
822_ftp_disconnect(int cd)
823{
824    (void)_ftp_cmd(cd, "QUIT");
825    close(cd);
826}
827
828/*
829 * Check if we're already connected
830 */
831static int
832_ftp_isconnected(struct url *url)
833{
834    return (cached_socket
835	    && (strcmp(url->host, cached_host.host) == 0)
836	    && (strcmp(url->user, cached_host.user) == 0)
837	    && (strcmp(url->pwd, cached_host.pwd) == 0)
838	    && (url->port == cached_host.port));
839}
840
841/*
842 * Check the cache, reconnect if no luck
843 */
844static int
845_ftp_cached_connect(struct url *url, struct url *purl, char *flags)
846{
847    int e, cd;
848
849    cd = -1;
850
851    /* set default port */
852    if (!url->port)
853	url->port = _fetch_default_port(url->scheme);
854
855    /* try to use previously cached connection */
856    if (_ftp_isconnected(url)) {
857	e = _ftp_cmd(cached_socket, "NOOP");
858	if (e == FTP_OK || e == FTP_SYNTAX_ERROR)
859	    return cached_socket;
860    }
861
862    /* connect to server */
863    if ((cd = _ftp_connect(url, purl, flags)) == -1)
864	return -1;
865    if (cached_socket)
866	_ftp_disconnect(cached_socket);
867    cached_socket = cd;
868    memcpy(&cached_host, url, sizeof *url);
869    return cd;
870}
871
872/*
873 * Check the proxy settings
874 */
875static struct url *
876_ftp_get_proxy(void)
877{
878    struct url *purl;
879    char *p;
880
881    if (((p = getenv("FTP_PROXY")) || (p = getenv("ftp_proxy")) ||
882	 (p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
883	*p && (purl = fetchParseURL(p)) != NULL) {
884	if (!*purl->scheme) {
885	    if (getenv("FTP_PROXY") || getenv("ftp_proxy"))
886		strcpy(purl->scheme, SCHEME_FTP);
887	    else
888		strcpy(purl->scheme, SCHEME_HTTP);
889	}
890	if (!purl->port)
891	    purl->port = _fetch_default_proxy_port(purl->scheme);
892	if (strcasecmp(purl->scheme, SCHEME_FTP) == 0 ||
893	    strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
894	    return purl;
895	fetchFreeURL(purl);
896    }
897    return NULL;
898}
899
900/*
901 * Get and stat file
902 */
903FILE *
904fetchXGetFTP(struct url *url, struct url_stat *us, char *flags)
905{
906    struct url *purl;
907    int cd;
908
909    /* get the proxy URL, and check if we should use HTTP instead */
910    if (!CHECK_FLAG('d') && (purl = _ftp_get_proxy()) != NULL) {
911	if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
912	    return _http_request(url, "GET", us, purl, flags);
913    } else {
914	purl = NULL;
915    }
916
917    /* connect to server */
918    cd = _ftp_cached_connect(url, purl, flags);
919    if (purl)
920	fetchFreeURL(purl);
921    if (cd == NULL)
922	return NULL;
923
924    /* change directory */
925    if (_ftp_cwd(cd, url->doc) == -1)
926	return NULL;
927
928    /* stat file */
929    if (us && _ftp_stat(cd, url->doc, us) == -1
930	&& fetchLastErrCode != FETCH_PROTO
931	&& fetchLastErrCode != FETCH_UNAVAIL)
932	return NULL;
933
934    /* initiate the transfer */
935    return _ftp_transfer(cd, "RETR", url->doc, O_RDONLY, url->offset, flags);
936}
937
938/*
939 * Get file
940 */
941FILE *
942fetchGetFTP(struct url *url, char *flags)
943{
944    return fetchXGetFTP(url, NULL, flags);
945}
946
947/*
948 * Put file
949 */
950FILE *
951fetchPutFTP(struct url *url, char *flags)
952{
953    struct url *purl;
954    int cd;
955
956    /* get the proxy URL, and check if we should use HTTP instead */
957    if (!CHECK_FLAG('d') && (purl = _ftp_get_proxy()) != NULL) {
958	if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
959	    /* XXX HTTP PUT is not implemented, so try without the proxy */
960	    purl = NULL;
961    } else {
962	purl = NULL;
963    }
964
965    /* connect to server */
966    cd = _ftp_cached_connect(url, purl, flags);
967    if (purl)
968	fetchFreeURL(purl);
969    if (cd == NULL)
970	return NULL;
971
972    /* change directory */
973    if (_ftp_cwd(cd, url->doc) == -1)
974	return NULL;
975
976    /* initiate the transfer */
977    return _ftp_transfer(cd, CHECK_FLAG('a') ? "APPE" : "STOR",
978			 url->doc, O_WRONLY, url->offset, flags);
979}
980
981/*
982 * Get file stats
983 */
984int
985fetchStatFTP(struct url *url, struct url_stat *us, char *flags)
986{
987    struct url *purl;
988    int cd;
989
990    /* get the proxy URL, and check if we should use HTTP instead */
991    if (!CHECK_FLAG('d') && (purl = _ftp_get_proxy()) != NULL) {
992	if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0) {
993	    FILE *f;
994
995	    if ((f = _http_request(url, "HEAD", us, purl, flags)) == NULL)
996		return -1;
997	    fclose(f);
998	    return 0;
999	}
1000    } else {
1001	purl = NULL;
1002    }
1003
1004    /* connect to server */
1005    cd = _ftp_cached_connect(url, purl, flags);
1006    if (purl)
1007	fetchFreeURL(purl);
1008    if (cd == NULL)
1009	return NULL;
1010
1011    /* change directory */
1012    if (_ftp_cwd(cd, url->doc) == -1)
1013	return -1;
1014
1015    /* stat file */
1016    return _ftp_stat(cd, url->doc, us);
1017}
1018
1019/*
1020 * List a directory
1021 */
1022extern void warnx(char *, ...);
1023struct url_ent *
1024fetchListFTP(struct url *url, char *flags)
1025{
1026    warnx("fetchListFTP(): not implemented");
1027    return NULL;
1028}
1029