xref: /netbsd-src/libexec/ftpd/conf.c (revision 481fca6e59249d8ffcf24fef7cfbe7b131bfb080)
1 /*	$NetBSD: conf.c,v 1.32 2000/07/09 02:24:30 sommerfeld Exp $	*/
2 
3 /*-
4  * Copyright (c) 1997-2000 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Simon Burge and 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 #include <sys/cdefs.h>
40 #ifndef lint
41 __RCSID("$NetBSD: conf.c,v 1.32 2000/07/09 02:24:30 sommerfeld Exp $");
42 #endif /* not lint */
43 
44 #include <sys/types.h>
45 #include <sys/param.h>
46 #include <sys/stat.h>
47 
48 #include <ctype.h>
49 #include <errno.h>
50 #include <fcntl.h>
51 #include <glob.h>
52 #include <setjmp.h>
53 #include <signal.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <stringlist.h>
58 #include <syslog.h>
59 #include <time.h>
60 #include <unistd.h>
61 #include <util.h>
62 
63 #ifdef KERBEROS5
64 #include <krb5/krb5.h>
65 #endif
66 
67 #include "extern.h"
68 #include "pathnames.h"
69 
70 static char *strend(const char *, char *);
71 static int filetypematch(char *, int);
72 
73 
74 /*
75  * Initialise curclass to an `empty' state
76  */
77 void
78 init_curclass(void)
79 {
80 	struct ftpconv	*conv, *cnext;
81 
82 	for (conv = curclass.conversions; conv != NULL; conv = cnext) {
83 		REASSIGN(conv->suffix, NULL);
84 		REASSIGN(conv->types, NULL);
85 		REASSIGN(conv->disable, NULL);
86 		REASSIGN(conv->command, NULL);
87 		cnext = conv->next;
88 		free(conv);
89 	}
90 
91 	curclass.checkportcmd = 0;
92 	REASSIGN(curclass.classname, NULL);
93 	curclass.conversions =	NULL;
94 	REASSIGN(curclass.display, NULL);
95 	curclass.limit =	-1;		/* unlimited connections */
96 	REASSIGN(curclass.limitfile, NULL);
97 	curclass.maxrateget =	0;
98 	curclass.maxrateput =	0;
99 	curclass.maxtimeout =	7200;		/* 2 hours */
100 	curclass.modify =	1;
101 	REASSIGN(curclass.motd, xstrdup(_PATH_FTPLOGINMESG));
102 	REASSIGN(curclass.notify, NULL);
103 	curclass.passive =	1;
104 	curclass.portmin =	0;
105 	curclass.portmax =	0;
106 	curclass.rateget =	0;
107 	curclass.rateput =	0;
108 	curclass.timeout =	900;		/* 15 minutes */
109 	curclass.umask =	027;
110 	curclass.upload =	1;
111 }
112 
113 /*
114  * Parse the configuration file, looking for the named class, and
115  * define curclass to contain the appropriate settings.
116  */
117 void
118 parse_conf(const char *findclass)
119 {
120 	FILE		*f;
121 	char		*buf, *p;
122 	size_t		 len;
123 	int		 none, match, rate;
124 	char		*endp;
125 	char		*class, *word, *arg, *template;
126 	const char	*infile;
127 	size_t		 line;
128 	unsigned int	 timeout;
129 	struct ftpconv	*conv, *cnext;
130 
131 	init_curclass();
132 	REASSIGN(curclass.classname, xstrdup(findclass));
133 	if (strcasecmp(findclass, "guest") == 0) {
134 		curclass.modify = 0;
135 		curclass.umask = 0707;
136 	}
137 
138 	infile = conffilename(_PATH_FTPDCONF);
139 	if ((f = fopen(infile, "r")) == NULL)
140 		return;
141 
142 	line = 0;
143 	template = NULL;
144 	for (;
145 	    (buf = fparseln(f, &len, &line, NULL, FPARSELN_UNESCCOMM |
146 	    		FPARSELN_UNESCCONT | FPARSELN_UNESCESC)) != NULL;
147 	    free(buf)) {
148 		none = match = 0;
149 		p = buf;
150 		if (len < 1)
151 			continue;
152 		if (p[len - 1] == '\n')
153 			p[--len] = '\0';
154 		if (EMPTYSTR(p))
155 			continue;
156 
157 		NEXTWORD(p, word);
158 		NEXTWORD(p, class);
159 		NEXTWORD(p, arg);
160 		if (EMPTYSTR(word) || EMPTYSTR(class))
161 			continue;
162 		if (strcasecmp(class, "none") == 0)
163 			none = 1;
164 		if (! (strcasecmp(class, findclass) == 0 ||
165 		       (template != NULL && strcasecmp(class, template) == 0) ||
166 		       none ||
167 		       strcasecmp(class, "all") == 0) )
168 			continue;
169 
170 		if (strcasecmp(word, "checkportcmd") == 0) {
171 			if (none ||
172 			    (!EMPTYSTR(arg) && strcasecmp(arg, "off") == 0))
173 				curclass.checkportcmd = 0;
174 			else
175 				curclass.checkportcmd = 1;
176 
177 		} else if (strcasecmp(word, "classtype") == 0) {
178 			if (!none && !EMPTYSTR(arg)) {
179 				if (strcasecmp(arg, "GUEST") == 0)
180 					curclass.type = CLASS_GUEST;
181 				else if (strcasecmp(arg, "CHROOT") == 0)
182 					curclass.type = CLASS_CHROOT;
183 				else if (strcasecmp(arg, "REAL") == 0)
184 					curclass.type = CLASS_REAL;
185 				else {
186 					syslog(LOG_WARNING,
187 				    "%s line %d: unknown class type `%s'",
188 					    infile, (int)line, arg);
189 					continue;
190 				}
191 			}
192 
193 		} else if (strcasecmp(word, "conversion") == 0) {
194 			char *suffix, *types, *disable, *convcmd;
195 
196 			if (EMPTYSTR(arg)) {
197 				syslog(LOG_WARNING,
198 				    "%s line %d: %s requires a suffix",
199 				    infile, (int)line, word);
200 				continue;	/* need a suffix */
201 			}
202 			NEXTWORD(p, types);
203 			NEXTWORD(p, disable);
204 			convcmd = p;
205 			if (convcmd)
206 				convcmd += strspn(convcmd, " \t");
207 			suffix = xstrdup(arg);
208 			if (none || EMPTYSTR(types) ||
209 			    EMPTYSTR(disable) || EMPTYSTR(convcmd)) {
210 				types = NULL;
211 				disable = NULL;
212 				convcmd = NULL;
213 			} else {
214 				types = xstrdup(types);
215 				disable = xstrdup(disable);
216 				convcmd = xstrdup(convcmd);
217 			}
218 			for (conv = curclass.conversions; conv != NULL;
219 			    conv = conv->next) {
220 				if (strcmp(conv->suffix, suffix) == 0)
221 					break;
222 			}
223 			if (conv == NULL) {
224 				conv = (struct ftpconv *)
225 				    calloc(1, sizeof(struct ftpconv));
226 				if (conv == NULL) {
227 					syslog(LOG_WARNING, "can't malloc");
228 					continue;
229 				}
230 				conv->next = NULL;
231 				for (cnext = curclass.conversions;
232 				    cnext != NULL; cnext = cnext->next)
233 					if (cnext->next == NULL)
234 						break;
235 				if (cnext != NULL)
236 					cnext->next = conv;
237 				else
238 					curclass.conversions = conv;
239 			}
240 			REASSIGN(conv->suffix, suffix);
241 			REASSIGN(conv->types, types);
242 			REASSIGN(conv->disable, disable);
243 			REASSIGN(conv->command, convcmd);
244 
245 		} else if (strcasecmp(word, "display") == 0) {
246 			if (none || EMPTYSTR(arg))
247 				arg = NULL;
248 			else
249 				arg = xstrdup(arg);
250 			REASSIGN(curclass.display, arg);
251 
252 		} else if (strcasecmp(word, "limit") == 0) {
253 			int limit;
254 
255 			if (none || EMPTYSTR(arg))
256 				continue;
257 			limit = (int)strtol(arg, &endp, 10);
258 			if (*endp != 0) {
259 				syslog(LOG_WARNING,
260 				    "%s line %d: invalid limit %s",
261 				    infile, (int)line, arg);
262 				continue;
263 			}
264 			curclass.limit = limit;
265 			REASSIGN(curclass.limitfile,
266 			    EMPTYSTR(p) ? NULL : xstrdup(p));
267 
268 		} else if (strcasecmp(word, "maxtimeout") == 0) {
269 			if (none || EMPTYSTR(arg))
270 				continue;
271 			timeout = (unsigned int)strtoul(arg, &endp, 10);
272 			if (*endp != 0) {
273 				syslog(LOG_WARNING,
274 				    "%s line %d: invalid maxtimeout %s",
275 				    infile, (int)line, arg);
276 				continue;
277 			}
278 			if (timeout < 30) {
279 				syslog(LOG_WARNING,
280 				    "%s line %d: maxtimeout %d < 30 seconds",
281 				    infile, (int)line, timeout);
282 				continue;
283 			}
284 			if (timeout < curclass.timeout) {
285 				syslog(LOG_WARNING,
286 				    "%s line %d: maxtimeout %d < timeout (%d)",
287 				    infile, (int)line, timeout,
288 				    curclass.timeout);
289 				continue;
290 			}
291 			curclass.maxtimeout = timeout;
292 
293 		} else if (strcasecmp(word, "modify") == 0) {
294 			if (none ||
295 			    (!EMPTYSTR(arg) && strcasecmp(arg, "off") == 0))
296 				curclass.modify = 0;
297 			else
298 				curclass.modify = 1;
299 
300 		} else if (strcasecmp(word, "motd") == 0) {
301 			if (none || EMPTYSTR(arg))
302 				arg = NULL;
303 			else
304 				arg = xstrdup(arg);
305 			REASSIGN(curclass.motd, arg);
306 
307 
308 		} else if (strcasecmp(word, "notify") == 0) {
309 			if (none || EMPTYSTR(arg))
310 				arg = NULL;
311 			else
312 				arg = xstrdup(arg);
313 			REASSIGN(curclass.notify, arg);
314 
315 		} else if (strcasecmp(word, "passive") == 0) {
316 			if (none ||
317 			    (!EMPTYSTR(arg) && strcasecmp(arg, "off") == 0))
318 				curclass.passive = 0;
319 			else
320 				curclass.passive = 1;
321 
322 		} else if (strcasecmp(word, "portrange") == 0) {
323 			int minport, maxport;
324 			char *min, *max;
325 
326 			if (none) {
327 				curclass.portmin = 0;
328 				curclass.portmax = 0;
329 				continue;
330 			}
331 			if (EMPTYSTR(arg))
332 				continue;
333 			min = arg;
334 			NEXTWORD(p, max);
335 			if (EMPTYSTR(max)) {
336 				syslog(LOG_WARNING,
337 				   "%s line %d: missing maxport argument",
338 				   infile, (int)line);
339 				continue;
340 			}
341 			minport = (int)strtol(min, &endp, 10);
342 			if (*endp != 0 || minport < IPPORT_RESERVED ||
343 			    minport > IPPORT_ANONMAX) {
344 				syslog(LOG_WARNING,
345 				    "%s line %d: invalid minport %s",
346 				    infile, (int)line, min);
347 				continue;
348 			}
349 			maxport = (int)strtol(max, &endp, 10);
350 			if (*endp != 0 || maxport < IPPORT_RESERVED ||
351 			    maxport > IPPORT_ANONMAX) {
352 				syslog(LOG_WARNING,
353 				    "%s line %d: invalid maxport %s",
354 				    infile, (int)line, max);
355 				continue;
356 			}
357 			if (minport >= maxport) {
358 				syslog(LOG_WARNING,
359 				    "%s line %d: minport %d >= maxport %d",
360 				    infile, (int)line, minport, maxport);
361 				continue;
362 			}
363 			curclass.portmin = minport;
364 			curclass.portmax = maxport;
365 
366 		} else if (strcasecmp(word, "rateget") == 0) {
367 			if (none || EMPTYSTR(arg))
368 				continue;
369 			rate = strsuftoi(arg);
370 			if (rate == -1) {
371 				syslog(LOG_WARNING,
372 				    "%s line %d: invalid rateget %s",
373 				    infile, (int)line, arg);
374 				continue;
375 			}
376 			curclass.maxrateget = rate;
377 			curclass.rateget = rate;
378 
379 		} else if (strcasecmp(word, "rateput") == 0) {
380 			if (none || EMPTYSTR(arg))
381 				continue;
382 			rate = strsuftoi(arg);
383 			if (rate == -1) {
384 				syslog(LOG_WARNING,
385 				    "%s line %d: invalid rateput %s",
386 				    infile, (int)line, arg);
387 				continue;
388 			}
389 			curclass.maxrateput = rate;
390 			curclass.rateput = rate;
391 
392 		} else if (strcasecmp(word, "timeout") == 0) {
393 			if (none || EMPTYSTR(arg))
394 				continue;
395 			timeout = (unsigned int)strtoul(arg, &endp, 10);
396 			if (*endp != 0) {
397 				syslog(LOG_WARNING,
398 				    "%s line %d: invalid timeout %s",
399 				    infile, (int)line, arg);
400 				continue;
401 			}
402 			if (timeout < 30) {
403 				syslog(LOG_WARNING,
404 				    "%s line %d: timeout %d < 30 seconds",
405 				    infile, (int)line, timeout);
406 				continue;
407 			}
408 			if (timeout > curclass.maxtimeout) {
409 				syslog(LOG_WARNING,
410 				    "%s line %d: timeout %d > maxtimeout (%d)",
411 				    infile, (int)line, timeout,
412 				    curclass.maxtimeout);
413 				continue;
414 			}
415 			curclass.timeout = timeout;
416 
417 		} else if (strcasecmp(word, "template") == 0) {
418 			if (none)
419 				continue;
420 			REASSIGN(template, EMPTYSTR(arg) ? NULL : xstrdup(arg));
421 
422 		} else if (strcasecmp(word, "umask") == 0) {
423 			mode_t umask;
424 
425 			if (none || EMPTYSTR(arg))
426 				continue;
427 			umask = (mode_t)strtoul(arg, &endp, 8);
428 			if (*endp != 0 || umask > 0777) {
429 				syslog(LOG_WARNING,
430 				    "%s line %d: invalid umask %s",
431 				    infile, (int)line, arg);
432 				continue;
433 			}
434 			curclass.umask = umask;
435 
436 		} else if (strcasecmp(word, "upload") == 0) {
437 			if (none ||
438 			    (!EMPTYSTR(arg) && strcasecmp(arg, "off") == 0)) {
439 				curclass.modify = 0;
440 				curclass.upload = 0;
441 			} else
442 				curclass.upload = 1;
443 
444 		} else {
445 			syslog(LOG_WARNING,
446 			    "%s line %d: unknown directive '%s'",
447 			    infile, (int)line, word);
448 			continue;
449 		}
450 	}
451 	REASSIGN(template, NULL);
452 	fclose(f);
453 }
454 
455 /*
456  * Show file listed in curclass.display first time in, and list all the
457  * files named in curclass.notify in the current directory.  Send back
458  * responses with the prefix `code' + "-".
459  */
460 void
461 show_chdir_messages(int code)
462 {
463 	static StringList *slist = NULL;
464 
465 	struct stat st;
466 	struct tm *t;
467 	glob_t	 gl;
468 	time_t	 now, then;
469 	int	 age;
470 	char	 cwd[MAXPATHLEN];
471 	char	*cp, **rlist;
472 
473 	if (quietmessages)
474 		return;
475 
476 		/* Setup list for directory cache */
477 	if (slist == NULL)
478 		slist = sl_init();
479 	if (slist == NULL) {
480 		syslog(LOG_WARNING, "can't allocate memory for stringlist");
481 		return;
482 	}
483 
484 		/* Check if this directory has already been visited */
485 	if (getcwd(cwd, sizeof(cwd) - 1) == NULL) {
486 		syslog(LOG_WARNING, "can't getcwd: %s", strerror(errno));
487 		return;
488 	}
489 	if (sl_find(slist, cwd) != NULL)
490 		return;
491 
492 	cp = xstrdup(cwd);
493 	if (sl_add(slist, cp) == -1)
494 		syslog(LOG_WARNING, "can't add `%s' to stringlist", cp);
495 
496 		/* First check for a display file */
497 	(void)format_file(curclass.display, code);
498 
499 		/* Now see if there are any notify files */
500 	if (EMPTYSTR(curclass.notify))
501 		return;
502 
503 	if (glob(curclass.notify, 0, NULL, &gl) != 0 || gl.gl_matchc == 0)
504 		return;
505 	time(&now);
506 	for (rlist = gl.gl_pathv; *rlist != NULL; rlist++) {
507 		if (stat(*rlist, &st) != 0)
508 			continue;
509 		if (!S_ISREG(st.st_mode))
510 			continue;
511 		then = st.st_mtime;
512 		if (code != 0) {
513 			reply(-code, "%s", "");
514 			code = 0;
515 		}
516 		reply(-code, "Please read the file %s", *rlist);
517 		t = localtime(&now);
518 		age = 365 * t->tm_year + t->tm_yday;
519 		t = localtime(&then);
520 		age -= 365 * t->tm_year + t->tm_yday;
521 		reply(-code, "  it was last modified on %.24s - %d day%s ago",
522 		    ctime(&then), age, PLURAL(age));
523 	}
524 	globfree(&gl);
525 }
526 
527 int
528 format_file(const char *file, int code)
529 {
530 	FILE   *f;
531 	char   *buf, *p, *cwd;
532 	size_t	len;
533 	time_t	now;
534 
535 	if (quietmessages)
536 		return (0);
537 
538 	if (EMPTYSTR(file))
539 		return(0);
540 	if ((f = fopen(file, "r")) == NULL)
541 		return (0);
542 	reply(-code, "%s", "");
543 
544 	for (;
545 	    (buf = fparseln(f, &len, NULL, "\0\0\0", 0)) != NULL; free(buf)) {
546 		if (len > 0)
547 			if (buf[len - 1] == '\n')
548 				buf[--len] = '\0';
549 		cprintf(stdout, "    ");
550 
551 		for (p = buf; *p; p++) {
552 			if (*p == '%') {
553 				p++;
554 				switch (*p) {
555 
556 				case 'c':
557 					cprintf(stdout, "%s",
558 					    curclass.classname ?
559 					    curclass.classname : "<unknown>");
560 					break;
561 
562 				case 'C':
563 					if (getcwd(cwd, sizeof(cwd)-1) == NULL){
564 						syslog(LOG_WARNING,
565 						    "can't getcwd: %s",
566 						    strerror(errno));
567 						continue;
568 					}
569 					cprintf(stdout, "%s", cwd);
570 					break;
571 
572 				case 'E':
573 						/* XXXX email address */
574 					break;
575 
576 				case 'L':
577 					cprintf(stdout, "%s", hostname);
578 					break;
579 
580 				case 'M':
581 					if (curclass.limit == -1)
582 						cprintf(stdout, "unlimited");
583 					else
584 						cprintf(stdout, "%d",
585 						    curclass.limit);
586 					break;
587 
588 				case 'N':
589 					if (connections > 0)
590 						cprintf(stdout, "%d",
591 						    connections);
592 					break;
593 
594 				case 'R':
595 					cprintf(stdout, "%s", remotehost);
596 					break;
597 
598 				case 'T':
599 					now = time(NULL);
600 					cprintf(stdout, "%.24s", ctime(&now));
601 					break;
602 
603 				case 'U':
604 					cprintf(stdout, "%s",
605 					    pw ? pw->pw_name : "<unknown>");
606 					break;
607 
608 				case '%':
609 					CPUTC('%', stdout);
610 					break;
611 
612 				}
613 			} else
614 				CPUTC(*p, stdout);
615 		}
616 		cprintf(stdout, "\r\n");
617 	}
618 
619 	(void)fflush(stdout);
620 	(void)fclose(f);
621 	return (1);
622 }
623 
624 /*
625  * Find s2 at the end of s1.  If found, return a string up to (but
626  * not including) s2, otherwise returns NULL.
627  */
628 static char *
629 strend(const char *s1, char *s2)
630 {
631 	static	char buf[MAXPATHLEN];
632 
633 	char	*start;
634 	size_t	l1, l2;
635 
636 	l1 = strlen(s1);
637 	l2 = strlen(s2);
638 
639 	if (l2 >= l1)
640 		return(NULL);
641 
642 	strlcpy(buf, s1, sizeof(buf));
643 	start = buf + (l1 - l2);
644 
645 	if (strcmp(start, s2) == 0) {
646 		*start = '\0';
647 		return(buf);
648 	} else
649 		return(NULL);
650 }
651 
652 static int
653 filetypematch(char *types, int mode)
654 {
655 	for ( ; types[0] != '\0'; types++)
656 		switch (*types) {
657 		  case 'd':
658 			if (S_ISDIR(mode))
659 				return(1);
660 			break;
661 		  case 'f':
662 			if (S_ISREG(mode))
663 				return(1);
664 			break;
665 		}
666 	return(0);
667 }
668 
669 /*
670  * Look for a conversion.  If we succeed, return a pointer to the
671  * command to execute for the conversion.
672  *
673  * The command is stored in a static array so there's no memory
674  * leak problems, and not too much to change in ftpd.c.  This
675  * routine doesn't need to be re-entrant unless we start using a
676  * multi-threaded ftpd, and that's not likely for a while...
677  */
678 char **
679 do_conversion(const char *fname)
680 {
681 	struct ftpconv	*cp;
682 	struct stat	 st;
683 	int		 o_errno;
684 	char		*base = NULL;
685 	char		*cmd, *p, *lp, **argv;
686 	StringList	*sl;
687 
688 	o_errno = errno;
689 	sl = NULL;
690 	cmd = NULL;
691 	for (cp = curclass.conversions; cp != NULL; cp = cp->next) {
692 		if (cp->suffix == NULL) {
693 			syslog(LOG_WARNING,
694 			    "cp->suffix==NULL in conv list; SHOULDN'T HAPPEN!");
695 			continue;
696 		}
697 		if ((base = strend(fname, cp->suffix)) == NULL)
698 			continue;
699 		if (cp->types == NULL || cp->disable == NULL ||
700 		    cp->command == NULL)
701 			continue;
702 					/* Is it enabled? */
703 		if (strcmp(cp->disable, ".") != 0 &&
704 		    stat(cp->disable, &st) == 0)
705 				continue;
706 					/* Does the base exist? */
707 		if (stat(base, &st) < 0)
708 			continue;
709 					/* Is the file type ok */
710 		if (!filetypematch(cp->types, st.st_mode))
711 			continue;
712 		break;			/* "We have a winner!" */
713 	}
714 
715 	/* If we got through the list, no conversion */
716 	if (cp == NULL)
717 		goto cleanup_do_conv;
718 
719 	/* Split up command into an argv */
720 	if ((sl = sl_init()) == NULL)
721 		goto cleanup_do_conv;
722 	cmd = xstrdup(cp->command);
723 	p = cmd;
724 	while (p) {
725 		NEXTWORD(p, lp);
726 		if (strcmp(lp, "%s") == 0)
727 			lp = base;
728 		if (sl_add(sl, xstrdup(lp)) == -1)
729 			goto cleanup_do_conv;
730 	}
731 
732 	if (sl_add(sl, NULL) == -1)
733 		goto cleanup_do_conv;
734 	argv = sl->sl_str;
735 	free(cmd);
736 	free(sl);
737 	return(argv);
738 
739  cleanup_do_conv:
740 	if (sl)
741 		sl_free(sl, 1);
742 	free(cmd);
743 	errno = o_errno;
744 	return(NULL);
745 }
746 
747 /*
748  * Convert the string `arg' to an int, which may have an optional SI suffix
749  * (`b', `k', `m', `g'). Returns the number for success, -1 otherwise.
750  */
751 int
752 strsuftoi(const char *arg)
753 {
754 	char *cp;
755 	long val;
756 
757 	if (!isdigit((unsigned char)arg[0]))
758 		return (-1);
759 
760 	val = strtol(arg, &cp, 10);
761 	if (cp != NULL) {
762 		if (cp[0] != '\0' && cp[1] != '\0')
763 			 return (-1);
764 		switch (tolower((unsigned char)cp[0])) {
765 		case '\0':
766 		case 'b':
767 			break;
768 		case 'k':
769 			val <<= 10;
770 			break;
771 		case 'm':
772 			val <<= 20;
773 			break;
774 		case 'g':
775 			val <<= 30;
776 			break;
777 		default:
778 			return (-1);
779 		}
780 	}
781 	if (val < 0 || val > INT_MAX)
782 		return (-1);
783 
784 	return (val);
785 }
786 
787 /*
788  * Count the number of current connections, reading from
789  *	/var/run/ftpd.pids-<class>
790  * Does a kill -0 on each pid in that file, and only counts
791  * processes that exist (or frees the slot if it doesn't).
792  * Adds getpid() to the first free slot. Truncates the file
793  * if possible.
794  */
795 void
796 count_users(void)
797 {
798 	char	fn[MAXPATHLEN];
799 	int	fd, i, last;
800 	size_t	count;
801 	pid_t  *pids, mypid;
802 	struct stat sb;
803 
804 	(void)strlcpy(fn, _PATH_CLASSPIDS, sizeof(fn));
805 	(void)strlcat(fn, curclass.classname, sizeof(fn));
806 	pids = NULL;
807 	connections = 1;
808 
809 	if ((fd = open(fn, O_RDWR | O_CREAT | O_EXLOCK, 0600)) == -1)
810 		return;
811 	if (fstat(fd, &sb) == -1)
812 		goto cleanup_count;
813 	if ((pids = malloc(sb.st_size + sizeof(pid_t))) == NULL)
814 		goto cleanup_count;
815 	count = read(fd, pids, sb.st_size);
816 	if (count < 0 || count != sb.st_size)
817 		goto cleanup_count;
818 	count /= sizeof(pid_t);
819 	mypid = getpid();
820 	last = 0;
821 	for (i = 0; i < count; i++) {
822 		if (pids[i] == 0)
823 			continue;
824 		if (kill(pids[i], 0) == -1 && errno != EPERM) {
825 			if (mypid != 0) {
826 				pids[i] = mypid;
827 				mypid = 0;
828 				last = i;
829 			}
830 		} else {
831 			connections++;
832 			last = i;
833 		}
834 	}
835 	if (mypid != 0) {
836 		if (pids[last] != 0)
837 			last++;
838 		pids[last] = mypid;
839 	}
840 	count = (last + 1) * sizeof(pid_t);
841 	if (lseek(fd, 0, SEEK_SET) == -1)
842 		goto cleanup_count;
843 	if (write(fd, pids, count) == -1)
844 		goto cleanup_count;
845 	(void)ftruncate(fd, count);
846 
847  cleanup_count:
848 	(void)flock(fd, LOCK_UN);
849 	close(fd);
850 	REASSIGN(pids, NULL);
851 }
852