xref: /netbsd-src/libexec/ftpd/cmds.c (revision 5e4c038a45edbc7d63b7c2daa76e29f88b64a4e3)
1 /*	$NetBSD: cmds.c,v 1.16 2002/02/13 15:15:23 lukem Exp $	*/
2 
3 /*
4  * Copyright (c) 1999-2001 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Luke Mewburn.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *        This product includes software developed by the NetBSD
21  *        Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 /*
40  * Copyright (c) 1985, 1988, 1990, 1992, 1993, 1994
41  *	The Regents of the University of California.  All rights reserved.
42  *
43  * Redistribution and use in source and binary forms, with or without
44  * modification, are permitted provided that the following conditions
45  * are met:
46  * 1. Redistributions of source code must retain the above copyright
47  *    notice, this list of conditions and the following disclaimer.
48  * 2. Redistributions in binary form must reproduce the above copyright
49  *    notice, this list of conditions and the following disclaimer in the
50  *    documentation and/or other materials provided with the distribution.
51  * 3. All advertising materials mentioning features or use of this software
52  *    must display the following acknowledgement:
53  *	This product includes software developed by the University of
54  *	California, Berkeley and its contributors.
55  * 4. Neither the name of the University nor the names of its contributors
56  *    may be used to endorse or promote products derived from this software
57  *    without specific prior written permission.
58  *
59  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
60  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
61  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
62  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
63  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
64  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
65  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
66  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
67  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
68  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
69  * SUCH DAMAGE.
70  */
71 
72 /*
73  * Copyright (C) 1997 and 1998 WIDE Project.
74  * All rights reserved.
75  *
76  * Redistribution and use in source and binary forms, with or without
77  * modification, are permitted provided that the following conditions
78  * are met:
79  * 1. Redistributions of source code must retain the above copyright
80  *    notice, this list of conditions and the following disclaimer.
81  * 2. Redistributions in binary form must reproduce the above copyright
82  *    notice, this list of conditions and the following disclaimer in the
83  *    documentation and/or other materials provided with the distribution.
84  * 3. Neither the name of the project nor the names of its contributors
85  *    may be used to endorse or promote products derived from this software
86  *    without specific prior written permission.
87  *
88  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
89  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
90  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
91  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
92  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
93  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
94  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
95  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
96  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
97  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
98  * SUCH DAMAGE.
99  */
100 
101 
102 #include <sys/cdefs.h>
103 #ifndef lint
104 __RCSID("$NetBSD: cmds.c,v 1.16 2002/02/13 15:15:23 lukem Exp $");
105 #endif /* not lint */
106 
107 #include <sys/param.h>
108 #include <sys/stat.h>
109 
110 #include <arpa/ftp.h>
111 
112 #include <dirent.h>
113 #include <errno.h>
114 #include <setjmp.h>
115 #include <stdio.h>
116 #include <stdlib.h>
117 #include <string.h>
118 #include <tzfile.h>
119 #include <unistd.h>
120 
121 #ifdef KERBEROS5
122 #include <krb5/krb5.h>
123 #endif
124 
125 #include "extern.h"
126 
127 typedef enum {
128 	FE_MLSD		= 1<<0,		/* if op is MLSD (MLST otherwise ) */
129 	FE_ISCURDIR	= 1<<1,		/* if name is the current directory */
130 } factflag_t;
131 
132 typedef struct {
133 	const char	*path;		/* full pathname */
134 	const char	*display;	/* name to display */
135 	struct stat	*stat;		/* stat of path */
136 	struct stat	*pdirstat;	/* stat of path's parent dir */
137 	factflag_t	 flags;		/* flags */
138 } factelem;
139 
140 static void	ack(const char *);
141 static void	base64_encode(const char *, size_t, char *, int);
142 static void	fact_type(const char *, FILE *, factelem *);
143 static void	fact_size(const char *, FILE *, factelem *);
144 static void	fact_modify(const char *, FILE *, factelem *);
145 static void	fact_perm(const char *, FILE *, factelem *);
146 static void	fact_unique(const char *, FILE *, factelem *);
147 static int	matchgroup(gid_t);
148 static void	mlsname(FILE *, factelem *);
149 static void	replydirname(const char *, const char *);
150 
151 struct ftpfact {
152 	const char	 *name;		/* name of fact */
153 	int		  enabled;	/* if fact is enabled */
154 	void		(*display)(const char *, FILE *, factelem *);
155 					/* function to display fact */
156 };
157 
158 struct ftpfact facttab[] = {
159 	{ "Type",	1, fact_type },
160 #define	FACT_TYPE 0
161 	{ "Size",	1, fact_size },
162 	{ "Modify",	1, fact_modify },
163 	{ "Perm",	1, fact_perm },
164 	{ "Unique",	1, fact_unique },
165 	/* "Create" */
166 	/* "Lang" */
167 	/* "Media-Type" */
168 	/* "CharSet" */
169 };
170 
171 #define FACTTABSIZE	(sizeof(facttab) / sizeof(struct ftpfact))
172 
173 
174 void
175 cwd(const char *path)
176 {
177 
178 	if (chdir(path) < 0)
179 		perror_reply(550, path);
180 	else {
181 		show_chdir_messages(250);
182 		ack("CWD");
183 	}
184 }
185 
186 void
187 delete(const char *name)
188 {
189 	char *p = NULL;
190 
191 	if (remove(name) < 0) {
192 		p = strerror(errno);
193 		perror_reply(550, name);
194 	} else
195 		ack("DELE");
196 	logxfer("delete", -1, name, NULL, NULL, p);
197 }
198 
199 void
200 feat(void)
201 {
202 	int i;
203 
204 	reply(-211, "Features supported");
205 	cprintf(stdout, " MDTM\r\n");
206 	cprintf(stdout, " MLST ");
207 	for (i = 0; i < FACTTABSIZE; i++)
208 		cprintf(stdout, "%s%s;", facttab[i].name,
209 		    facttab[i].enabled ? "*" : "");
210 	cprintf(stdout, "\r\n");
211 	cprintf(stdout, " REST STREAM\r\n");
212 	cprintf(stdout, " SIZE\r\n");
213 	cprintf(stdout, " TVFS\r\n");
214 	reply(211,  "End");
215 }
216 
217 void
218 makedir(const char *name)
219 {
220 	char *p = NULL;
221 
222 	if (mkdir(name, 0777) < 0) {
223 		p = strerror(errno);
224 		perror_reply(550, name);
225 	} else
226 		replydirname(name, "directory created.");
227 	logxfer("mkdir", -1, name, NULL, NULL, p);
228 }
229 
230 void
231 mlsd(const char *path)
232 {
233 	struct dirent	*dp;
234 	struct stat	 sb, pdirstat;
235 	factelem f;
236 	FILE	*dout;
237 	DIR	*dirp;
238 	char	name[MAXPATHLEN];
239 	int	hastypefact;
240 
241 	hastypefact = facttab[FACT_TYPE].enabled;
242 	if (path == NULL)
243 		path = ".";
244 	if (stat(path, &pdirstat) == -1) {
245  mlsdperror:
246 		perror_reply(550, path);
247 		return;
248 	}
249 	if (! S_ISDIR(pdirstat.st_mode)) {
250 		errno = ENOTDIR;
251 		perror_reply(501, path);
252 		return;
253 	}
254 	if ((dirp = opendir(path)) == NULL)
255 		goto mlsdperror;
256 
257 	dout = dataconn("MLSD", (off_t)-1, "w");
258 	if (dout == NULL)
259 		return;
260 
261 	memset(&f, 0, sizeof(f));
262 	f.stat = &sb;
263 	f.flags |= FE_MLSD;
264 	while ((dp = readdir(dirp)) != NULL) {
265 		snprintf(name, sizeof(name), "%s/%s", path, dp->d_name);
266 		if (ISDOTDIR(dp->d_name)) {	/* special case curdir: */
267 			if (! hastypefact)
268 				continue;
269 			f.pdirstat = NULL;	/*   require stat of parent */
270 			f.display = path;	/*   set name to real name */
271 			f.flags |= FE_ISCURDIR; /*   flag name is curdir */
272 		} else {
273 			if (ISDOTDOTDIR(dp->d_name)) {
274 				if (! hastypefact)
275 					continue;
276 				f.pdirstat = NULL;
277 			} else
278 				f.pdirstat = &pdirstat;	/* cache parent stat */
279 			f.display = dp->d_name;
280 			f.flags &= ~FE_ISCURDIR;
281 		}
282 		if (stat(name, &sb) == -1)
283 			continue;
284 		f.path = name;
285 		mlsname(dout, &f);
286 	}
287 	(void)closedir(dirp);
288 
289 	if (ferror(dout) != 0)
290 		perror_reply(550, "Data connection");
291 	else
292 		reply(226, "MLSD complete.");
293 	closedataconn(dout);
294 	total_xfers_out++;
295 	total_xfers++;
296 }
297 
298 void
299 mlst(const char *path)
300 {
301 	struct stat sb;
302 	factelem f;
303 
304 	if (path == NULL)
305 		path = ".";
306 	if (stat(path, &sb) == -1) {
307 		perror_reply(550, path);
308 		return;
309 	}
310 	reply(-250, "MLST %s", path);
311 	memset(&f, 0, sizeof(f));
312 	f.path = path;
313 	f.display = path;
314 	f.stat = &sb;
315 	f.pdirstat = NULL;
316 	CPUTC(' ', stdout);
317 	mlsname(stdout, &f);
318 	reply(250, "End");
319 }
320 
321 
322 void
323 opts(const char *command)
324 {
325 	struct tab *c;
326 	char *ep;
327 
328 	if ((ep = strchr(command, ' ')) != NULL)
329 		*ep++ = '\0';
330 	c = lookup(cmdtab, command);
331 	if (c == NULL) {
332 		reply(502, "Unknown command %s.", command);
333 		return;
334 	}
335 	if (! CMD_IMPLEMENTED(c)) {
336 		reply(501, "%s command not implemented.", c->name);
337 		return;
338 	}
339 	if (! CMD_HAS_OPTIONS(c)) {
340 		reply(501, "%s command does not support persistent options.",
341 		    c->name);
342 		return;
343 	}
344 
345 			/* special case: MLST */
346 	if (strcasecmp(command, "MLST") == 0) {
347 		int	 enabled[FACTTABSIZE];
348 		int	 i, onedone;
349 		size_t	 len;
350 		char	*p;
351 
352 		for (i = 0; i < sizeof(enabled) / sizeof(int); i++)
353 			enabled[i] = 0;
354 		if (ep == NULL || *ep == '\0')
355 			goto displaymlstopts;
356 
357 				/* don't like spaces, and need trailing ; */
358 		len = strlen(ep);
359 		if (strchr(ep, ' ') != NULL || ep[len - 1] != ';') {
360  badmlstopt:
361 			reply(501, "Invalid MLST options");
362 			return;
363 		}
364 		ep[len - 1] = '\0';
365 		while ((p = strsep(&ep, ";")) != NULL) {
366 			if (*p == '\0')
367 				goto badmlstopt;
368 			for (i = 0; i < FACTTABSIZE; i++)
369 				if (strcasecmp(p, facttab[i].name) == 0) {
370 					enabled[i] = 1;
371 					break;
372 				}
373 		}
374 
375  displaymlstopts:
376 		for (i = 0; i < FACTTABSIZE; i++)
377 			facttab[i].enabled = enabled[i];
378 		cprintf(stdout, "200 MLST OPTS");
379 		for (i = onedone = 0; i < FACTTABSIZE; i++) {
380 			if (facttab[i].enabled) {
381 				cprintf(stdout, "%s%s;", onedone ? "" : " ",
382 				    facttab[i].name);
383 				onedone++;
384 			}
385 		}
386 		cprintf(stdout, "\r\n");
387 		fflush(stdout);
388 		return;
389 	}
390 
391 			/* default cases */
392 	if (ep != NULL && *ep != '\0')
393 		REASSIGN(c->options, xstrdup(ep));
394 	if (c->options != NULL)
395 		reply(200, "Options for %s are '%s'.", c->name,
396 		    c->options);
397 	else
398 		reply(200, "No options defined for %s.", c->name);
399 }
400 
401 void
402 pwd(void)
403 {
404 	char path[MAXPATHLEN];
405 
406 	if (getcwd(path, sizeof(path) - 1) == NULL)
407 		reply(550, "Can't get the current directory: %s.",
408 		    strerror(errno));
409 	else
410 		replydirname(path, "is the current directory.");
411 }
412 
413 void
414 removedir(const char *name)
415 {
416 	char *p = NULL;
417 
418 	if (rmdir(name) < 0) {
419 		p = strerror(errno);
420 		perror_reply(550, name);
421 	} else
422 		ack("RMD");
423 	logxfer("rmdir", -1, name, NULL, NULL, p);
424 }
425 
426 char *
427 renamefrom(const char *name)
428 {
429 	struct stat st;
430 
431 	if (stat(name, &st) < 0) {
432 		perror_reply(550, name);
433 		return (NULL);
434 	}
435 	reply(350, "File exists, ready for destination name");
436 	return (xstrdup(name));
437 }
438 
439 void
440 renamecmd(const char *from, const char *to)
441 {
442 	char *p = NULL;
443 
444 	if (rename(from, to) < 0) {
445 		p = strerror(errno);
446 		perror_reply(550, "rename");
447 	} else
448 		ack("RNTO");
449 	logxfer("rename", -1, from, to, NULL, p);
450 }
451 
452 void
453 sizecmd(const char *filename)
454 {
455 	switch (type) {
456 	case TYPE_L:
457 	case TYPE_I:
458 	    {
459 		struct stat stbuf;
460 		if (stat(filename, &stbuf) < 0 || !S_ISREG(stbuf.st_mode))
461 			reply(550, "%s: not a plain file.", filename);
462 		else
463 			reply(213, ULLF, (ULLT)stbuf.st_size);
464 		break;
465 	    }
466 	case TYPE_A:
467 	    {
468 		FILE *fin;
469 		int c;
470 		off_t count;
471 		struct stat stbuf;
472 		fin = fopen(filename, "r");
473 		if (fin == NULL) {
474 			perror_reply(550, filename);
475 			return;
476 		}
477 		if (fstat(fileno(fin), &stbuf) < 0 || !S_ISREG(stbuf.st_mode)) {
478 			reply(550, "%s: not a plain file.", filename);
479 			(void) fclose(fin);
480 			return;
481 		}
482 		if (stbuf.st_size > 10240) {
483 			reply(550, "%s: file too large for SIZE.", filename);
484 			(void) fclose(fin);
485 			return;
486 		}
487 
488 		count = 0;
489 		while((c = getc(fin)) != EOF) {
490 			if (c == '\n')	/* will get expanded to \r\n */
491 				count++;
492 			count++;
493 		}
494 		(void) fclose(fin);
495 
496 		reply(213, LLF, (LLT)count);
497 		break;
498 	    }
499 	default:
500 		reply(504, "SIZE not implemented for Type %c.", "?AEIL"[type]);
501 	}
502 }
503 
504 void
505 statfilecmd(const char *filename)
506 {
507 	FILE *fin;
508 	int c;
509 	char *argv[] = { INTERNAL_LS, "-lgA", "", NULL };
510 
511 	argv[2] = (char *)filename;
512 	fin = ftpd_popen(argv, "r", STDOUT_FILENO);
513 	reply(-211, "status of %s:", filename);
514 /* XXX: use fgetln() or fparseln() here? */
515 	while ((c = getc(fin)) != EOF) {
516 		if (c == '\n') {
517 			if (ferror(stdout)){
518 				perror_reply(421, "control connection");
519 				(void) ftpd_pclose(fin);
520 				dologout(1);
521 				/* NOTREACHED */
522 			}
523 			if (ferror(fin)) {
524 				perror_reply(551, filename);
525 				(void) ftpd_pclose(fin);
526 				return;
527 			}
528 			CPUTC('\r', stdout);
529 		}
530 		CPUTC(c, stdout);
531 	}
532 	(void) ftpd_pclose(fin);
533 	reply(211, "End of Status");
534 }
535 
536 /* -- */
537 
538 static void
539 ack(const char *s)
540 {
541 
542 	reply(250, "%s command successful.", s);
543 }
544 
545 /*
546  * Encode len bytes starting at clear using base64 encoding into encoded,
547  * which should be at least ((len + 2) * 4 / 3 + 1) in size.
548  * If nulterm is non-zero, terminate with \0 otherwise pad to 3 byte boundary
549  * with `='.
550  */
551 static void
552 base64_encode(const char *clear, size_t len, char *encoded, int nulterm)
553 {
554 	static const char base64[] =
555 	    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
556 	const char *c;
557 	char	*e, termchar;
558 	int	 i;
559 
560 			/* determine whether to pad with '=' or NUL terminate */
561 	termchar = nulterm ? '\0' : '=';
562 	c = clear;
563 	e = encoded;
564 			/* convert all but last 2 bytes */
565 	for (i = len; i > 2; i -= 3, c += 3) {
566 		*e++ = base64[(c[0] >> 2) & 0x3f];
567 		*e++ = base64[((c[0] << 4) & 0x30) | ((c[1] >> 4) & 0x0f)];
568 		*e++ = base64[((c[1] << 2) & 0x3c) | ((c[2] >> 6) & 0x03)];
569 		*e++ = base64[(c[2]) & 0x3f];
570 	}
571 			/* handle slop at end */
572 	if (i > 0) {
573 		*e++ = base64[(c[0] >> 2) & 0x3f];
574 		*e++ = base64[((c[0] << 4) & 0x30) |
575 		     (i > 1 ? ((c[1] >> 4) & 0x0f) : 0)];
576 		*e++ = (i > 1) ? base64[(c[1] << 2) & 0x3c] : termchar;
577 		*e++ = termchar;
578 	}
579 	*e = '\0';
580 }
581 
582 static void
583 fact_modify(const char *fact, FILE *fd, factelem *fe)
584 {
585 	struct tm *t;
586 
587 	t = gmtime(&(fe->stat->st_mtime));
588 	cprintf(fd, "%s=%04d%02d%02d%02d%02d%02d;", fact,
589 	    TM_YEAR_BASE + t->tm_year,
590 	    t->tm_mon+1, t->tm_mday,
591 	    t->tm_hour, t->tm_min, t->tm_sec);
592 }
593 
594 static void
595 fact_perm(const char *fact, FILE *fd, factelem *fe)
596 {
597 	int		rok, wok, xok, pdirwok;
598 	struct stat	*pdir;
599 
600 	if (fe->stat->st_uid == geteuid()) {
601 		rok = ((fe->stat->st_mode & S_IRUSR) != 0);
602 		wok = ((fe->stat->st_mode & S_IWUSR) != 0);
603 		xok = ((fe->stat->st_mode & S_IXUSR) != 0);
604 	} else if (matchgroup(fe->stat->st_gid)) {
605 		rok = ((fe->stat->st_mode & S_IRGRP) != 0);
606 		wok = ((fe->stat->st_mode & S_IWGRP) != 0);
607 		xok = ((fe->stat->st_mode & S_IXGRP) != 0);
608 	} else {
609 		rok = ((fe->stat->st_mode & S_IROTH) != 0);
610 		wok = ((fe->stat->st_mode & S_IWOTH) != 0);
611 		xok = ((fe->stat->st_mode & S_IXOTH) != 0);
612 	}
613 
614 	cprintf(fd, "%s=", fact);
615 
616 			/*
617 			 * if parent info not provided, look it up, but
618 			 * only if the current class has modify rights,
619 			 * since we only need this info in such a case.
620 			 */
621 	pdir = fe->pdirstat;
622 	if (pdir == NULL && CURCLASS_FLAGS_ISSET(modify)) {
623 		size_t		len;
624 		char		realdir[MAXPATHLEN], *p;
625 		struct stat	dir;
626 
627 		len = strlcpy(realdir, fe->path, sizeof(realdir));
628 		if (len < sizeof(realdir) - 4) {
629 			if (S_ISDIR(fe->stat->st_mode))
630 				strlcat(realdir, "/..", sizeof(realdir));
631 			else {
632 					/* if has a /, move back to it */
633 					/* otherwise use '..' */
634 				if ((p = strrchr(realdir, '/')) != NULL) {
635 					if (p == realdir)
636 						p++;
637 					*p = '\0';
638 				} else
639 					strlcpy(realdir, "..", sizeof(realdir));
640 			}
641 			if (stat(realdir, &dir) == 0)
642 				pdir = &dir;
643 		}
644 	}
645 	pdirwok = 0;
646 	if (pdir != NULL) {
647 		if (pdir->st_uid == geteuid())
648 			pdirwok = ((pdir->st_mode & S_IWUSR) != 0);
649 		else if (matchgroup(pdir->st_gid))
650 			pdirwok = ((pdir->st_mode & S_IWGRP) != 0);
651 		else
652 			pdirwok = ((pdir->st_mode & S_IWOTH) != 0);
653 	}
654 
655 			/* 'a': can APPE to file */
656 	if (wok && CURCLASS_FLAGS_ISSET(upload) && S_ISREG(fe->stat->st_mode))
657 		CPUTC('a', fd);
658 
659 			/* 'c': can create or append to files in directory */
660 	if (wok && CURCLASS_FLAGS_ISSET(modify) && S_ISDIR(fe->stat->st_mode))
661 		CPUTC('c', fd);
662 
663 			/* 'd': can delete file or directory */
664 	if (pdirwok && CURCLASS_FLAGS_ISSET(modify)) {
665 		int candel;
666 
667 		candel = 1;
668 		if (S_ISDIR(fe->stat->st_mode)) {
669 			DIR *dirp;
670 			struct dirent *dp;
671 
672 			if ((dirp = opendir(fe->display)) == NULL)
673 				candel = 0;
674 			else {
675 				while ((dp = readdir(dirp)) != NULL) {
676 					if (ISDOTDIR(dp->d_name) ||
677 					    ISDOTDOTDIR(dp->d_name))
678 						continue;
679 					candel = 0;
680 					break;
681 				}
682 				closedir(dirp);
683 			}
684 		}
685 		if (candel)
686 			CPUTC('d', fd);
687 	}
688 
689 			/* 'e': can enter directory */
690 	if (xok && S_ISDIR(fe->stat->st_mode))
691 		CPUTC('e', fd);
692 
693 			/* 'f': can rename file or directory */
694 	if (pdirwok && CURCLASS_FLAGS_ISSET(modify))
695 		CPUTC('f', fd);
696 
697 			/* 'l': can list directory */
698 	if (rok && xok && S_ISDIR(fe->stat->st_mode))
699 		CPUTC('l', fd);
700 
701 			/* 'm': can create directory */
702 	if (wok && CURCLASS_FLAGS_ISSET(modify) && S_ISDIR(fe->stat->st_mode))
703 		CPUTC('m', fd);
704 
705 			/* 'p': can remove files in directory */
706 	if (wok && CURCLASS_FLAGS_ISSET(modify) && S_ISDIR(fe->stat->st_mode))
707 		CPUTC('p', fd);
708 
709 			/* 'r': can RETR file */
710 	if (rok && S_ISREG(fe->stat->st_mode))
711 		CPUTC('r', fd);
712 
713 			/* 'w': can STOR file */
714 	if (wok && CURCLASS_FLAGS_ISSET(upload) && S_ISREG(fe->stat->st_mode))
715 		CPUTC('w', fd);
716 
717 	CPUTC(';', fd);
718 }
719 
720 static void
721 fact_size(const char *fact, FILE *fd, factelem *fe)
722 {
723 
724 	if (S_ISREG(fe->stat->st_mode))
725 		cprintf(fd, "%s=" LLF ";", fact, (LLT)fe->stat->st_size);
726 }
727 
728 static void
729 fact_type(const char *fact, FILE *fd, factelem *fe)
730 {
731 
732 	cprintf(fd, "%s=", fact);
733 	switch (fe->stat->st_mode & S_IFMT) {
734 	case S_IFDIR:
735 		if (fe->flags & FE_MLSD) {
736 			if ((fe->flags & FE_ISCURDIR) || ISDOTDIR(fe->display))
737 				cprintf(fd, "cdir");
738 			else if (ISDOTDOTDIR(fe->display))
739 				cprintf(fd, "pdir");
740 			else
741 				cprintf(fd, "dir");
742 		} else {
743 			cprintf(fd, "dir");
744 		}
745 		break;
746 	case S_IFREG:
747 		cprintf(fd, "file");
748 		break;
749 	case S_IFIFO:
750 		cprintf(fd, "OS.unix=fifo");
751 		break;
752 	case S_IFLNK:		/* XXX: probably a NO-OP with stat() */
753 		cprintf(fd, "OS.unix=slink");
754 		break;
755 	case S_IFSOCK:
756 		cprintf(fd, "OS.unix=socket");
757 		break;
758 	case S_IFBLK:
759 	case S_IFCHR:
760 		cprintf(fd, "OS.unix=%s-%d/%d",
761 		    S_ISBLK(fe->stat->st_mode) ? "blk" : "chr",
762 		    major(fe->stat->st_rdev), minor(fe->stat->st_rdev));
763 		break;
764 	default:
765 		cprintf(fd, "OS.unix=UNKNOWN(0%o)", fe->stat->st_mode & S_IFMT);
766 		break;
767 	}
768 	CPUTC(';', fd);
769 }
770 
771 static void
772 fact_unique(const char *fact, FILE *fd, factelem *fe)
773 {
774 	char obuf[(sizeof(dev_t) + sizeof(ino_t) + 2) * 4 / 3 + 2];
775 	char tbuf[sizeof(dev_t) + sizeof(ino_t)];
776 
777 	memcpy(tbuf,
778 	    (char *)&(fe->stat->st_dev), sizeof(dev_t));
779 	memcpy(tbuf + sizeof(dev_t),
780 	    (char *)&(fe->stat->st_ino), sizeof(ino_t));
781 	base64_encode(tbuf, sizeof(dev_t) + sizeof(ino_t), obuf, 1);
782 	cprintf(fd, "%s=%s;", fact, obuf);
783 }
784 
785 static int
786 matchgroup(gid_t gid)
787 {
788 	int	i;
789 
790 	for (i = 0; i < gidcount; i++)
791 		if (gid == gidlist[i])
792 			return(1);
793 	return (0);
794 }
795 
796 static void
797 mlsname(FILE *fp, factelem *fe)
798 {
799 	char realfile[MAXPATHLEN];
800 	int i, userf;
801 
802 	for (i = 0; i < FACTTABSIZE; i++) {
803 		if (facttab[i].enabled)
804 			(facttab[i].display)(facttab[i].name, fp, fe);
805 	}
806 	if ((fe->flags & FE_MLSD) &&
807 	    !(fe->flags & FE_ISCURDIR) && !ISDOTDIR(fe->display)) {
808 			/* if MLSD and not "." entry, display as-is */
809 		userf = 0;
810 	} else {
811 			/* if MLST, or MLSD and "." entry, realpath(3) it */
812 		if (realpath(fe->display, realfile) != NULL)
813 			userf = 1;
814 	}
815 	cprintf(fp, " %s\r\n", userf ? realfile : fe->display);
816 }
817 
818 static void
819 replydirname(const char *name, const char *message)
820 {
821 	char *p, *ep;
822 	char npath[MAXPATHLEN * 2];
823 
824 	p = npath;
825 	ep = &npath[sizeof(npath) - 1];
826 	while (*name) {
827 		if (*name == '"') {
828 			if (ep - p < 2)
829 				break;
830 			*p++ = *name++;
831 			*p++ = '"';
832 		} else {
833 			if (ep - p < 1)
834 				break;
835 			*p++ = *name++;
836 		}
837 	}
838 	*p = '\0';
839 	reply(257, "\"%s\" %s", npath, message);
840 }
841