ftp.c revision 89589 
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
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: head/lib/libfetch/ftp.c 89589 2002-01-20 19:52:25Z des $");
31
32/*
33 * Portions of this code were taken from or based on ftpio.c:
34 *
35 * ----------------------------------------------------------------------------
36 * "THE BEER-WARE LICENSE" (Revision 42):
37 * <phk@login.dknet.dk> wrote this file.  As long as you retain this notice you
38 * can do whatever you want with this stuff. If we meet some day, and you think
39 * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
40 * ----------------------------------------------------------------------------
41 *
42 * Major Changelog:
43 *
44 * Dag-Erling Co�dan Sm�rgrav
45 * 9 Jun 1998
46 *
47 * Incorporated into libfetch
48 *
49 * Jordan K. Hubbard
50 * 17 Jan 1996
51 *
52 * Turned inside out. Now returns xfers as new file ids, not as a special
53 * `state' of FTP_t
54 *
55 * $ftpioId: ftpio.c,v 1.30 1998/04/11 07:28:53 phk Exp $
56 *
57 */
58
59#include <sys/param.h>
60#include <sys/socket.h>
61#include <netinet/in.h>
62
63#include <ctype.h>
64#include <err.h>
65#include <errno.h>
66#include <fcntl.h>
67#include <netdb.h>
68#include <stdarg.h>
69#include <stdio.h>
70#include <stdlib.h>
71#include <string.h>
72#include <time.h>
73#include <unistd.h>
74
75#include "fetch.h"
76#include "common.h"
77#include "ftperr.h"
78
79#define FTP_ANONYMOUS_USER	"anonymous"
80
81#define FTP_CONNECTION_ALREADY_OPEN	125
82#define FTP_OPEN_DATA_CONNECTION	150
83#define FTP_OK				200
84#define FTP_FILE_STATUS			213
85#define FTP_SERVICE_READY		220
86#define FTP_TRANSFER_COMPLETE		226
87#define FTP_PASSIVE_MODE		227
88#define FTP_LPASSIVE_MODE		228
89#define FTP_EPASSIVE_MODE		229
90#define FTP_LOGGED_IN			230
91#define FTP_FILE_ACTION_OK		250
92#define FTP_NEED_PASSWORD		331
93#define FTP_NEED_ACCOUNT		332
94#define FTP_FILE_OK			350
95#define FTP_SYNTAX_ERROR		500
96#define FTP_PROTOCOL_ERROR		999
97
98static struct url cached_host;
99static int cached_socket;
100
101static char *last_reply;
102static size_t lr_size, lr_length;
103static int last_code;
104
105#define isftpreply(foo) (isdigit(foo[0]) && isdigit(foo[1]) \
106			 && isdigit(foo[2]) \
107                         && (foo[3] == ' ' || foo[3] == '\0'))
108#define isftpinfo(foo) (isdigit(foo[0]) && isdigit(foo[1]) \
109			&& isdigit(foo[2]) && foo[3] == '-')
110
111/* translate IPv4 mapped IPv6 address to IPv4 address */
112static void
113unmappedaddr(struct sockaddr_in6 *sin6)
114{
115    struct sockaddr_in *sin4;
116    u_int32_t addr;
117    int port;
118
119    if (sin6->sin6_family != AF_INET6 ||
120	!IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
121	return;
122    sin4 = (struct sockaddr_in *)sin6;
123    addr = *(u_int32_t *)&sin6->sin6_addr.s6_addr[12];
124    port = sin6->sin6_port;
125    memset(sin4, 0, sizeof(struct sockaddr_in));
126    sin4->sin_addr.s_addr = addr;
127    sin4->sin_port = port;
128    sin4->sin_family = AF_INET;
129    sin4->sin_len = sizeof(struct sockaddr_in);
130}
131
132/*
133 * Get server response
134 */
135static int
136_ftp_chkerr(int cd)
137{
138    if (_fetch_getln(cd, &last_reply, &lr_size, &lr_length) == -1) {
139	_fetch_syserr();
140	return -1;
141    }
142    if (isftpinfo(last_reply)) {
143	while (lr_length && !isftpreply(last_reply)) {
144	    if (_fetch_getln(cd, &last_reply, &lr_size, &lr_length) == -1) {
145		_fetch_syserr();
146		return -1;
147	    }
148	}
149    }
150
151    while (lr_length && isspace(last_reply[lr_length-1]))
152	lr_length--;
153    last_reply[lr_length] = 0;
154
155    if (!isftpreply(last_reply)) {
156	_ftp_seterr(FTP_PROTOCOL_ERROR);
157	return -1;
158    }
159
160    last_code = (last_reply[0] - '0') * 100
161	+ (last_reply[1] - '0') * 10
162	+ (last_reply[2] - '0');
163
164    return last_code;
165}
166
167/*
168 * Send a command and check reply
169 */
170static int
171_ftp_cmd(int cd, const char *fmt, ...)
172{
173    va_list ap;
174    size_t len;
175    char *msg;
176    int r;
177
178    va_start(ap, fmt);
179    len = vasprintf(&msg, fmt, ap);
180    va_end(ap);
181
182    if (msg == NULL) {
183	errno = ENOMEM;
184	_fetch_syserr();
185	return -1;
186    }
187
188    r = _fetch_putln(cd, msg, len);
189    free(msg);
190
191    if (r == -1) {
192	_fetch_syserr();
193	return -1;
194    }
195
196    return _ftp_chkerr(cd);
197}
198
199/*
200 * Return a pointer to the filename part of a path
201 */
202static const char *
203_ftp_filename(const char *file)
204{
205    char *s;
206
207    if ((s = strrchr(file, '/')) == NULL)
208	return file;
209    else
210	return s + 1;
211}
212
213/*
214 * Change working directory to the directory that contains the
215 * specified file.
216 */
217static int
218_ftp_cwd(int cd, const char *file)
219{
220    char *s;
221    int e;
222
223    if ((s = strrchr(file, '/')) == NULL || s == file) {
224	e = _ftp_cmd(cd, "CWD /");
225    } else {
226	e = _ftp_cmd(cd, "CWD %.*s", s - file, file);
227    }
228    if (e != FTP_FILE_ACTION_OK) {
229	_ftp_seterr(e);
230	return -1;
231    }
232    return 0;
233}
234
235/*
236 * Request and parse file stats
237 */
238static int
239_ftp_stat(int cd, const char *file, struct url_stat *us)
240{
241    char *ln;
242    const char *s;
243    struct tm tm;
244    time_t t;
245    int e;
246
247    us->size = -1;
248    us->atime = us->mtime = 0;
249
250    if ((s = strrchr(file, '/')) == NULL)
251	s = file;
252    else
253	++s;
254
255    if ((e = _ftp_cmd(cd, "SIZE %s", s)) != FTP_FILE_STATUS) {
256	_ftp_seterr(e);
257	return -1;
258    }
259    for (ln = last_reply + 4; *ln && isspace(*ln); ln++)
260	/* nothing */ ;
261    for (us->size = 0; *ln && isdigit(*ln); ln++)
262	us->size = us->size * 10 + *ln - '0';
263    if (*ln && !isspace(*ln)) {
264	_ftp_seterr(FTP_PROTOCOL_ERROR);
265	us->size = -1;
266	return -1;
267    }
268    if (us->size == 0)
269	us->size = -1;
270    DEBUG(fprintf(stderr, "size: [%lld]\n", (long long)us->size));
271
272    if ((e = _ftp_cmd(cd, "MDTM %s", s)) != FTP_FILE_STATUS) {
273	_ftp_seterr(e);
274	return -1;
275    }
276    for (ln = last_reply + 4; *ln && isspace(*ln); ln++)
277	/* nothing */ ;
278    switch (strspn(ln, "0123456789")) {
279    case 14:
280	break;
281    case 15:
282	ln++;
283	ln[0] = '2';
284	ln[1] = '0';
285	break;
286    default:
287	_ftp_seterr(FTP_PROTOCOL_ERROR);
288	return -1;
289    }
290    if (sscanf(ln, "%04d%02d%02d%02d%02d%02d",
291	       &tm.tm_year, &tm.tm_mon, &tm.tm_mday,
292	       &tm.tm_hour, &tm.tm_min, &tm.tm_sec) != 6) {
293	_ftp_seterr(FTP_PROTOCOL_ERROR);
294	return -1;
295    }
296    tm.tm_mon--;
297    tm.tm_year -= 1900;
298    tm.tm_isdst = -1;
299    t = timegm(&tm);
300    if (t == (time_t)-1)
301	t = time(NULL);
302    us->mtime = t;
303    us->atime = t;
304    DEBUG(fprintf(stderr, "last modified: [%04d-%02d-%02d %02d:%02d:%02d]\n",
305		  tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
306		  tm.tm_hour, tm.tm_min, tm.tm_sec));
307    return 0;
308}
309
310/*
311 * I/O functions for FTP
312 */
313struct ftpio {
314    int		 csd;		/* Control socket descriptor */
315    int		 dsd;		/* Data socket descriptor */
316    int		 dir;		/* Direction */
317    int		 eof;		/* EOF reached */
318    int		 err;		/* Error code */
319};
320
321static int	_ftp_readfn(void *, char *, int);
322static int	_ftp_writefn(void *, const char *, int);
323static fpos_t	_ftp_seekfn(void *, fpos_t, int);
324static int	_ftp_closefn(void *);
325
326static int
327_ftp_readfn(void *v, char *buf, int len)
328{
329    struct ftpio *io;
330    int r;
331
332    io = (struct ftpio *)v;
333    if (io == NULL) {
334	errno = EBADF;
335	return -1;
336    }
337    if (io->csd == -1 || io->dsd == -1 || io->dir == O_WRONLY) {
338	errno = EBADF;
339	return -1;
340    }
341    if (io->err) {
342	errno = io->err;
343	return -1;
344    }
345    if (io->eof)
346	return 0;
347    r = read(io->dsd, buf, len);
348    if (r > 0)
349	return r;
350    if (r == 0) {
351	io->eof = 1;
352	return 0;
353    }
354    if (errno != EINTR)
355	io->err = errno;
356    return -1;
357}
358
359static int
360_ftp_writefn(void *v, const char *buf, int len)
361{
362    struct ftpio *io;
363    int w;
364
365    io = (struct ftpio *)v;
366    if (io == NULL) {
367	errno = EBADF;
368	return -1;
369    }
370    if (io->csd == -1 || io->dsd == -1 || io->dir == O_RDONLY) {
371	errno = EBADF;
372	return -1;
373    }
374    if (io->err) {
375	errno = io->err;
376	return -1;
377    }
378    w = write(io->dsd, buf, len);
379    if (w >= 0)
380	return w;
381    if (errno != EINTR)
382	io->err = errno;
383    return -1;
384}
385
386static fpos_t
387_ftp_seekfn(void *v, fpos_t pos __unused, int whence __unused)
388{
389    struct ftpio *io;
390
391    io = (struct ftpio *)v;
392    if (io == NULL) {
393	errno = EBADF;
394	return -1;
395    }
396    errno = ESPIPE;
397    return -1;
398}
399
400static int
401_ftp_closefn(void *v)
402{
403    struct ftpio *io;
404    int r;
405
406    io = (struct ftpio *)v;
407    if (io == NULL) {
408	errno = EBADF;
409	return -1;
410    }
411    if (io->dir == -1)
412	return 0;
413    if (io->csd == -1 || io->dsd == -1) {
414	errno = EBADF;
415	return -1;
416    }
417    close(io->dsd);
418    io->dir = -1;
419    io->dsd = -1;
420    DEBUG(fprintf(stderr, "Waiting for final status\n"));
421    r = _ftp_chkerr(io->csd);
422    close(io->csd);
423    free(io);
424    return (r == FTP_TRANSFER_COMPLETE) ? 0 : -1;
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, const char *oper, const char *file,
450	      int mode, off_t offset, const char *flags)
451{
452    struct sockaddr_storage sa;
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 sa;
473    if (getsockname(cd, (struct sockaddr *)&sa, &l) == -1)
474	goto sysouch;
475    if (sa.ss_family == AF_INET6)
476	unmappedaddr((struct sockaddr_in6 *)&sa);
477
478    /* open data socket */
479    if ((sd = socket(sa.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	unsigned int i;
488	int port;
489
490	/* send PASV command */
491	if (verbose)
492	    _fetch_info("setting passive mode");
493	switch (sa.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 sa;
558	if (getpeername(cd, (struct sockaddr *)&sa, &l) == -1)
559	    goto sysouch;
560	if (sa.ss_family == AF_INET6)
561	    unmappedaddr((struct sockaddr_in6 *)&sa);
562	switch (sa.ss_family) {
563	case AF_INET6:
564	    sin6 = (struct sockaddr_in6 *)&sa;
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 *)&sa;
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 *)&sa, sa.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 (sa.ss_family) {
607	case AF_INET6:
608	    ((struct sockaddr_in6 *)&sa)->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 *)&sa)->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 *)&sa, sa.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 *)&sa, &l) == -1)
633	    goto sysouch;
634	switch (sa.ss_family) {
635	case AF_INET:
636	    sin4 = (struct sockaddr_in *)&sa;
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 *)&sa;
648	    if (getnameinfo((struct sockaddr *)&sa, sa.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 * Authenticate
716 */
717static int
718_ftp_authenticate(int cd, struct url *url, struct url *purl)
719{
720    const char *user, *pwd, *logname;
721    char pbuf[MAXHOSTNAMELEN + MAXLOGNAME + 1];
722    int e, len;
723
724    /* XXX FTP_AUTH, and maybe .netrc */
725
726    /* send user name and password */
727    user = url->user;
728    if (!user || !*user)
729	user = getenv("FTP_LOGIN");
730    if (!user || !*user)
731	user = FTP_ANONYMOUS_USER;
732    if (purl && url->port == _fetch_default_port(url->scheme))
733	e = _ftp_cmd(cd, "USER %s@%s", user, url->host);
734    else if (purl)
735	e = _ftp_cmd(cd, "USER %s@%s@%d", user, url->host, url->port);
736    else
737	e = _ftp_cmd(cd, "USER %s", user);
738
739    /* did the server request a password? */
740    if (e == FTP_NEED_PASSWORD) {
741	pwd = url->pwd;
742	if (!pwd || !*pwd)
743	    pwd = getenv("FTP_PASSWORD");
744	if (!pwd || !*pwd) {
745	    if ((logname = getlogin()) == 0)
746		logname = FTP_ANONYMOUS_USER;
747	    if ((len = snprintf(pbuf, MAXLOGNAME + 1, "%s@", logname)) < 0)
748		len = 0;
749	    else if (len > MAXLOGNAME)
750	        len = MAXLOGNAME;
751	    gethostname(pbuf + len, sizeof pbuf - len);
752	    pwd = pbuf;
753	}
754	e = _ftp_cmd(cd, "PASS %s", pwd);
755    }
756
757    return e;
758}
759
760/*
761 * Log on to FTP server
762 */
763static int
764_ftp_connect(struct url *url, struct url *purl, const char *flags)
765{
766    int cd, e, direct, verbose;
767#ifdef INET6
768    int af = AF_UNSPEC;
769#else
770    int af = AF_INET;
771#endif
772
773    direct = CHECK_FLAG('d');
774    verbose = CHECK_FLAG('v');
775    if (CHECK_FLAG('4'))
776	af = AF_INET;
777    else if (CHECK_FLAG('6'))
778	af = AF_INET6;
779
780    if (direct)
781	purl = NULL;
782
783    /* check for proxy */
784    if (purl) {
785	/* XXX proxy authentication! */
786	cd = _fetch_connect(purl->host, purl->port, af, verbose);
787    } else {
788	/* no proxy, go straight to target */
789	cd = _fetch_connect(url->host, url->port, af, verbose);
790	purl = NULL;
791    }
792
793    /* check connection */
794    if (cd == -1) {
795	_fetch_syserr();
796	return NULL;
797    }
798
799    /* expect welcome message */
800    if ((e = _ftp_chkerr(cd)) != FTP_SERVICE_READY)
801	goto fouch;
802
803    /* authenticate */
804    if ((e = _ftp_authenticate(cd, url, purl)) != FTP_LOGGED_IN)
805	goto fouch;
806
807    /* might as well select mode and type at once */
808#ifdef FTP_FORCE_STREAM_MODE
809    if ((e = _ftp_cmd(cd, "MODE S")) != FTP_OK) /* default is S */
810	goto fouch;
811#endif
812    if ((e = _ftp_cmd(cd, "TYPE I")) != FTP_OK) /* default is A */
813	goto fouch;
814
815    /* done */
816    return cd;
817
818fouch:
819    if (e != -1)
820	_ftp_seterr(e);
821    close(cd);
822    return NULL;
823}
824
825/*
826 * Disconnect from server
827 */
828static void
829_ftp_disconnect(int cd)
830{
831    (void)_ftp_cmd(cd, "QUIT");
832    close(cd);
833}
834
835/*
836 * Check if we're already connected
837 */
838static int
839_ftp_isconnected(struct url *url)
840{
841    return (cached_socket
842	    && (strcmp(url->host, cached_host.host) == 0)
843	    && (strcmp(url->user, cached_host.user) == 0)
844	    && (strcmp(url->pwd, cached_host.pwd) == 0)
845	    && (url->port == cached_host.port));
846}
847
848/*
849 * Check the cache, reconnect if no luck
850 */
851static int
852_ftp_cached_connect(struct url *url, struct url *purl, const char *flags)
853{
854    int e, cd;
855
856    cd = -1;
857
858    /* set default port */
859    if (!url->port)
860	url->port = _fetch_default_port(url->scheme);
861
862    /* try to use previously cached connection */
863    if (_ftp_isconnected(url)) {
864	e = _ftp_cmd(cached_socket, "NOOP");
865	if (e == FTP_OK || e == FTP_SYNTAX_ERROR)
866	    return cached_socket;
867    }
868
869    /* connect to server */
870    if ((cd = _ftp_connect(url, purl, flags)) == -1)
871	return -1;
872    if (cached_socket)
873	_ftp_disconnect(cached_socket);
874    cached_socket = cd;
875    memcpy(&cached_host, url, sizeof *url);
876    return cd;
877}
878
879/*
880 * Check the proxy settings
881 */
882static struct url *
883_ftp_get_proxy(void)
884{
885    struct url *purl;
886    char *p;
887
888    if (((p = getenv("FTP_PROXY")) || (p = getenv("ftp_proxy")) ||
889	 (p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
890	*p && (purl = fetchParseURL(p)) != NULL) {
891	if (!*purl->scheme) {
892	    if (getenv("FTP_PROXY") || getenv("ftp_proxy"))
893		strcpy(purl->scheme, SCHEME_FTP);
894	    else
895		strcpy(purl->scheme, SCHEME_HTTP);
896	}
897	if (!purl->port)
898	    purl->port = _fetch_default_proxy_port(purl->scheme);
899	if (strcasecmp(purl->scheme, SCHEME_FTP) == 0 ||
900	    strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
901	    return purl;
902	fetchFreeURL(purl);
903    }
904    return NULL;
905}
906
907/*
908 * Process an FTP request
909 */
910FILE *
911_ftp_request(struct url *url, const char *op, struct url_stat *us,
912	     struct url *purl, const char *flags)
913{
914    int cd, oflag;
915
916    /* check if we should use HTTP instead */
917    if (purl && strcasecmp(purl->scheme, SCHEME_HTTP) == 0) {
918	if (strcmp(op, "STAT") == 0)
919	    return _http_request(url, "HEAD", us, purl, flags);
920	else if (strcmp(op, "RETR") == 0)
921	    return _http_request(url, "GET", us, purl, flags);
922	/*
923	 * Our HTTP code doesn't support PUT requests yet, so try a
924	 * direct connection.
925	 */
926    }
927
928    /* connect to server */
929    cd = _ftp_cached_connect(url, purl, flags);
930    if (purl)
931	fetchFreeURL(purl);
932    if (cd == NULL)
933	return NULL;
934
935    /* change directory */
936    if (_ftp_cwd(cd, url->doc) == -1)
937	return NULL;
938
939    /* stat file */
940    if (us && _ftp_stat(cd, url->doc, us) == -1
941	&& fetchLastErrCode != FETCH_PROTO
942	&& fetchLastErrCode != FETCH_UNAVAIL)
943	return NULL;
944
945    /* just a stat */
946    if (strcmp(op, "STAT") == 0)
947	return (FILE *)1; /* bogus return value */
948    if (strcmp(op, "STOR") == 0 || strcmp(op, "APPE") == 0)
949	oflag = O_WRONLY;
950    else
951	oflag = O_RDONLY;
952
953    /* initiate the transfer */
954    return _ftp_transfer(cd, op, url->doc, oflag, url->offset, flags);
955}
956
957/*
958 * Get and stat file
959 */
960FILE *
961fetchXGetFTP(struct url *url, struct url_stat *us, const char *flags)
962{
963    return _ftp_request(url, "RETR", us, _ftp_get_proxy(), flags);
964}
965
966/*
967 * Get file
968 */
969FILE *
970fetchGetFTP(struct url *url, const char *flags)
971{
972    return fetchXGetFTP(url, NULL, flags);
973}
974
975/*
976 * Put file
977 */
978FILE *
979fetchPutFTP(struct url *url, const char *flags)
980{
981
982    return _ftp_request(url, CHECK_FLAG('a') ? "APPE" : "STOR", NULL,
983			_ftp_get_proxy(), flags);
984}
985
986/*
987 * Get file stats
988 */
989int
990fetchStatFTP(struct url *url, struct url_stat *us, const char *flags)
991{
992
993    if (_ftp_request(url, "STAT", us, _ftp_get_proxy(), flags) == NULL)
994	return -1;
995    return 0;
996}
997
998/*
999 * List a directory
1000 */
1001struct url_ent *
1002fetchListFTP(struct url *url __unused, const char *flags __unused)
1003{
1004    warnx("fetchListFTP(): not implemented");
1005    return NULL;
1006}
1007