ftp.c revision 87315 
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 87315 2001-12-04 01:09:19Z 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: [\033[1m%lld\033[m]\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: [\033[1m%04d-%02d-%02d "
305		  "%02d:%02d:%02d\033[m]\n",
306		  tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
307		  tm.tm_hour, tm.tm_min, tm.tm_sec));
308    return 0;
309}
310
311/*
312 * I/O functions for FTP
313 */
314struct ftpio {
315    int		 csd;		/* Control socket descriptor */
316    int		 dsd;		/* Data socket descriptor */
317    int		 dir;		/* Direction */
318    int		 eof;		/* EOF reached */
319    int		 err;		/* Error code */
320};
321
322static int	_ftp_readfn(void *, char *, int);
323static int	_ftp_writefn(void *, const char *, int);
324static fpos_t	_ftp_seekfn(void *, fpos_t, int);
325static int	_ftp_closefn(void *);
326
327static int
328_ftp_readfn(void *v, char *buf, int len)
329{
330    struct ftpio *io;
331    int r;
332
333    io = (struct ftpio *)v;
334    if (io == NULL) {
335	errno = EBADF;
336	return -1;
337    }
338    if (io->csd == -1 || io->dsd == -1 || io->dir == O_WRONLY) {
339	errno = EBADF;
340	return -1;
341    }
342    if (io->err) {
343	errno = io->err;
344	return -1;
345    }
346    if (io->eof)
347	return 0;
348    r = read(io->dsd, buf, len);
349    if (r > 0)
350	return r;
351    if (r == 0) {
352	io->eof = 1;
353	return 0;
354    }
355    if (errno != EINTR)
356	io->err = errno;
357    return -1;
358}
359
360static int
361_ftp_writefn(void *v, const char *buf, int len)
362{
363    struct ftpio *io;
364    int w;
365
366    io = (struct ftpio *)v;
367    if (io == NULL) {
368	errno = EBADF;
369	return -1;
370    }
371    if (io->csd == -1 || io->dsd == -1 || io->dir == O_RDONLY) {
372	errno = EBADF;
373	return -1;
374    }
375    if (io->err) {
376	errno = io->err;
377	return -1;
378    }
379    w = write(io->dsd, buf, len);
380    if (w >= 0)
381	return w;
382    if (errno != EINTR)
383	io->err = errno;
384    return -1;
385}
386
387static fpos_t
388_ftp_seekfn(void *v, fpos_t pos __unused, int whence __unused)
389{
390    struct ftpio *io;
391
392    io = (struct ftpio *)v;
393    if (io == NULL) {
394	errno = EBADF;
395	return -1;
396    }
397    errno = ESPIPE;
398    return -1;
399}
400
401static int
402_ftp_closefn(void *v)
403{
404    struct ftpio *io;
405    int r;
406
407    io = (struct ftpio *)v;
408    if (io == NULL) {
409	errno = EBADF;
410	return -1;
411    }
412    if (io->dir == -1)
413	return 0;
414    if (io->csd == -1 || io->dsd == -1) {
415	errno = EBADF;
416	return -1;
417    }
418    close(io->dsd);
419    io->dir = -1;
420    io->dsd = -1;
421    DEBUG(fprintf(stderr, "Waiting for final status\n"));
422    r = _ftp_chkerr(io->csd);
423    close(io->csd);
424    free(io);
425    return (r == FTP_TRANSFER_COMPLETE) ? 0 : -1;
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, const char *oper, const char *file,
451	      int mode, off_t offset, const char *flags)
452{
453    struct sockaddr_storage sa;
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 sa;
474    if (getsockname(cd, (struct sockaddr *)&sa, &l) == -1)
475	goto sysouch;
476    if (sa.ss_family == AF_INET6)
477	unmappedaddr((struct sockaddr_in6 *)&sa);
478
479    /* open data socket */
480    if ((sd = socket(sa.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	unsigned int i;
489	int port;
490
491	/* send PASV command */
492	if (verbose)
493	    _fetch_info("setting passive mode");
494	switch (sa.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 sa;
559	if (getpeername(cd, (struct sockaddr *)&sa, &l) == -1)
560	    goto sysouch;
561	if (sa.ss_family == AF_INET6)
562	    unmappedaddr((struct sockaddr_in6 *)&sa);
563	switch (sa.ss_family) {
564	case AF_INET6:
565	    sin6 = (struct sockaddr_in6 *)&sa;
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 *)&sa;
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 *)&sa, sa.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 (sa.ss_family) {
608	case AF_INET6:
609	    ((struct sockaddr_in6 *)&sa)->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 *)&sa)->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 *)&sa, sa.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 *)&sa, &l) == -1)
634	    goto sysouch;
635	switch (sa.ss_family) {
636	case AF_INET:
637	    sin4 = (struct sockaddr_in *)&sa;
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 *)&sa;
649	    if (getnameinfo((struct sockaddr *)&sa, sa.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 * Authenticate
717 */
718static int
719_ftp_authenticate(int cd, struct url *url, struct url *purl)
720{
721    const char *user, *pwd, *logname;
722    char pbuf[MAXHOSTNAMELEN + MAXLOGNAME + 1];
723    int e, len;
724
725    /* XXX FTP_AUTH, and maybe .netrc */
726
727    /* send user name and password */
728    user = url->user;
729    if (!user || !*user)
730	user = getenv("FTP_LOGIN");
731    if (!user || !*user)
732	user = FTP_ANONYMOUS_USER;
733    if (purl && url->port == _fetch_default_port(url->scheme))
734	e = _ftp_cmd(cd, "USER %s@%s", user, url->host);
735    else if (purl)
736	e = _ftp_cmd(cd, "USER %s@%s@%d", user, url->host, url->port);
737    else
738	e = _ftp_cmd(cd, "USER %s", user);
739
740    /* did the server request a password? */
741    if (e == FTP_NEED_PASSWORD) {
742	pwd = url->pwd;
743	if (!pwd || !*pwd)
744	    pwd = getenv("FTP_PASSWORD");
745	if (!pwd || !*pwd) {
746	    if ((logname = getlogin()) == 0)
747		logname = FTP_ANONYMOUS_USER;
748	    if ((len = snprintf(pbuf, MAXLOGNAME + 1, "%s@", logname)) < 0)
749		len = 0;
750	    else if (len > MAXLOGNAME)
751	        len = MAXLOGNAME;
752	    gethostname(pbuf + len, sizeof pbuf - len);
753	    pwd = pbuf;
754	}
755	e = _ftp_cmd(cd, "PASS %s", pwd);
756    }
757
758    return e;
759}
760
761/*
762 * Log on to FTP server
763 */
764static int
765_ftp_connect(struct url *url, struct url *purl, const char *flags)
766{
767    int cd, e, direct, verbose;
768#ifdef INET6
769    int af = AF_UNSPEC;
770#else
771    int af = AF_INET;
772#endif
773
774    direct = CHECK_FLAG('d');
775    verbose = CHECK_FLAG('v');
776    if (CHECK_FLAG('4'))
777	af = AF_INET;
778    else if (CHECK_FLAG('6'))
779	af = AF_INET6;
780
781    if (direct)
782	purl = NULL;
783
784    /* check for proxy */
785    if (purl) {
786	/* XXX proxy authentication! */
787	cd = _fetch_connect(purl->host, purl->port, af, verbose);
788    } else {
789	/* no proxy, go straight to target */
790	cd = _fetch_connect(url->host, url->port, af, verbose);
791	purl = NULL;
792    }
793
794    /* check connection */
795    if (cd == -1) {
796	_fetch_syserr();
797	return NULL;
798    }
799
800    /* expect welcome message */
801    if ((e = _ftp_chkerr(cd)) != FTP_SERVICE_READY)
802	goto fouch;
803
804    /* authenticate */
805    if ((e = _ftp_authenticate(cd, url, purl)) != FTP_LOGGED_IN)
806	goto fouch;
807
808    /* might as well select mode and type at once */
809#ifdef FTP_FORCE_STREAM_MODE
810    if ((e = _ftp_cmd(cd, "MODE S")) != FTP_OK) /* default is S */
811	goto fouch;
812#endif
813    if ((e = _ftp_cmd(cd, "TYPE I")) != FTP_OK) /* default is A */
814	goto fouch;
815
816    /* done */
817    return cd;
818
819fouch:
820    if (e != -1)
821	_ftp_seterr(e);
822    close(cd);
823    return NULL;
824}
825
826/*
827 * Disconnect from server
828 */
829static void
830_ftp_disconnect(int cd)
831{
832    (void)_ftp_cmd(cd, "QUIT");
833    close(cd);
834}
835
836/*
837 * Check if we're already connected
838 */
839static int
840_ftp_isconnected(struct url *url)
841{
842    return (cached_socket
843	    && (strcmp(url->host, cached_host.host) == 0)
844	    && (strcmp(url->user, cached_host.user) == 0)
845	    && (strcmp(url->pwd, cached_host.pwd) == 0)
846	    && (url->port == cached_host.port));
847}
848
849/*
850 * Check the cache, reconnect if no luck
851 */
852static int
853_ftp_cached_connect(struct url *url, struct url *purl, const char *flags)
854{
855    int e, cd;
856
857    cd = -1;
858
859    /* set default port */
860    if (!url->port)
861	url->port = _fetch_default_port(url->scheme);
862
863    /* try to use previously cached connection */
864    if (_ftp_isconnected(url)) {
865	e = _ftp_cmd(cached_socket, "NOOP");
866	if (e == FTP_OK || e == FTP_SYNTAX_ERROR)
867	    return cached_socket;
868    }
869
870    /* connect to server */
871    if ((cd = _ftp_connect(url, purl, flags)) == -1)
872	return -1;
873    if (cached_socket)
874	_ftp_disconnect(cached_socket);
875    cached_socket = cd;
876    memcpy(&cached_host, url, sizeof *url);
877    return cd;
878}
879
880/*
881 * Check the proxy settings
882 */
883static struct url *
884_ftp_get_proxy(void)
885{
886    struct url *purl;
887    char *p;
888
889    if (((p = getenv("FTP_PROXY")) || (p = getenv("ftp_proxy")) ||
890	 (p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
891	*p && (purl = fetchParseURL(p)) != NULL) {
892	if (!*purl->scheme) {
893	    if (getenv("FTP_PROXY") || getenv("ftp_proxy"))
894		strcpy(purl->scheme, SCHEME_FTP);
895	    else
896		strcpy(purl->scheme, SCHEME_HTTP);
897	}
898	if (!purl->port)
899	    purl->port = _fetch_default_proxy_port(purl->scheme);
900	if (strcasecmp(purl->scheme, SCHEME_FTP) == 0 ||
901	    strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
902	    return purl;
903	fetchFreeURL(purl);
904    }
905    return NULL;
906}
907
908/*
909 * Process an FTP request
910 */
911FILE *
912_ftp_request(struct url *url, const char *op, struct url_stat *us,
913	     struct url *purl, const char *flags)
914{
915    int cd;
916
917    /* check if we should use HTTP instead */
918    if (purl && strcasecmp(purl->scheme, SCHEME_HTTP) == 0) {
919	if (strcmp(op, "STAT") == 0)
920	    return _http_request(url, "HEAD", us, purl, flags);
921	else if (strcmp(op, "RETR") == 0)
922	    return _http_request(url, "GET", us, purl, flags);
923	/*
924	 * Our HTTP code doesn't support PUT requests yet, so try a
925	 * direct connection.
926	 */
927    }
928
929    /* connect to server */
930    cd = _ftp_cached_connect(url, purl, flags);
931    if (purl)
932	fetchFreeURL(purl);
933    if (cd == NULL)
934	return NULL;
935
936    /* change directory */
937    if (_ftp_cwd(cd, url->doc) == -1)
938	return NULL;
939
940    /* stat file */
941    if (us && _ftp_stat(cd, url->doc, us) == -1
942	&& fetchLastErrCode != FETCH_PROTO
943	&& fetchLastErrCode != FETCH_UNAVAIL)
944	return NULL;
945
946    /* just a stat */
947    if (strcmp(op, "STAT") == 0)
948	return (FILE *)1; /* bogus return value */
949
950    /* initiate the transfer */
951    return _ftp_transfer(cd, op, url->doc, O_RDONLY, url->offset, flags);
952}
953
954/*
955 * Get and stat file
956 */
957FILE *
958fetchXGetFTP(struct url *url, struct url_stat *us, const char *flags)
959{
960    return _ftp_request(url, "RETR", us, _ftp_get_proxy(), flags);
961}
962
963/*
964 * Get file
965 */
966FILE *
967fetchGetFTP(struct url *url, const char *flags)
968{
969    return fetchXGetFTP(url, NULL, flags);
970}
971
972/*
973 * Put file
974 */
975FILE *
976fetchPutFTP(struct url *url, const char *flags)
977{
978
979    return _ftp_request(url, CHECK_FLAG('a') ? "APPE" : "STOR", NULL,
980			_ftp_get_proxy(), flags);
981}
982
983/*
984 * Get file stats
985 */
986int
987fetchStatFTP(struct url *url, struct url_stat *us, const char *flags)
988{
989
990    if (_ftp_request(url, "STAT", us, _ftp_get_proxy(), flags) == NULL)
991	return -1;
992    return 0;
993}
994
995/*
996 * List a directory
997 */
998struct url_ent *
999fetchListFTP(struct url *url __unused, const char *flags __unused)
1000{
1001    warnx("fetchListFTP(): not implemented");
1002    return NULL;
1003}
1004