1 /*
2  * utils.c - various utility functions used in pppd.
3  *
4  * Copyright (c) 2000-2001 by Sun Microsystems, Inc.
5  * All rights reserved.
6  *
7  * Permission to use, copy, modify, and distribute this software and its
8  * documentation is hereby granted, provided that the above copyright
9  * notice appears in all copies.
10  *
11  * SUN MAKES NO REPRESENTATION OR WARRANTIES ABOUT THE SUITABILITY OF
12  * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
13  * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
14  * PARTICULAR PURPOSE, OR NON-INFRINGEMENT.  SUN SHALL NOT BE LIABLE FOR
15  * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
16  * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES
17  *
18  * Copyright (c) 1999 The Australian National University.
19  * All rights reserved.
20  *
21  * Redistribution and use in source and binary forms are permitted
22  * provided that the above copyright notice and this paragraph are
23  * duplicated in all such forms and that any documentation,
24  * advertising materials, and other materials related to such
25  * distribution and use acknowledge that the software was developed
26  * by the Australian National University.  The name of the University
27  * may not be used to endorse or promote products derived from this
28  * software without specific prior written permission.
29  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
30  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
31  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
32  */
33 
34 #pragma ident	"%Z%%M%	%I%	%E% SMI"
35 #define RCSID	"$Id: utils.c,v 1.10 2000/03/27 01:36:48 paulus Exp $"
36 
37 #ifdef __linux__
38 #define	_GNU_SOURCE
39 #endif
40 #include <stdio.h>
41 #include <ctype.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include <unistd.h>
45 #include <signal.h>
46 #include <errno.h>
47 #include <fcntl.h>
48 #include <syslog.h>
49 #include <netdb.h>
50 #include <utmp.h>
51 #include <pwd.h>
52 #include <sys/param.h>
53 #include <sys/types.h>
54 #include <sys/wait.h>
55 #include <sys/time.h>
56 #include <sys/resource.h>
57 #include <sys/stat.h>
58 #include <sys/socket.h>
59 #include <netinet/in.h>
60 #ifdef SVR4
61 #include <sys/mkdev.h>
62 #endif
63 
64 #include "pppd.h"
65 
66 #if !defined(lint) && !defined(_lint)
67 static const char rcsid[] = RCSID;
68 #endif
69 
70 #if defined(SUNOS4)
71 extern char *strerror();
72 #endif
73 
74 /* Don't log to stdout until we're sure it's ok to do so. */
75 bool early_log = 1;
76 
77 static void pr_log __P((void *, const char *, ...));
78 static void logit __P((int, const char *, va_list));
79 static void vslp_printer __P((void *, const char *, ...));
80 static void format_packet __P((u_char *, int,
81     void (*) (void *, const char *, ...), void *));
82 
83 struct buffer_info {
84     char *ptr;
85     int len;
86 };
87 
88 /*
89  * strllen - like strlen, but doesn't run past end of input.
90  */
91 size_t
92 strllen(str, len)
93     const char *str;
94     size_t len;
95 {
96     size_t ret;
97 
98     for (ret = 0; ret < len; ret++)
99 	if (*str++ == '\0')
100 	    break;
101     return (ret);
102 }
103 
104 /*
105  * strlcpy - like strcpy/strncpy, doesn't overflow destination buffer,
106  * always leaves destination null-terminated (for len > 0).
107  */
108 size_t
109 strlcpy(dest, src, len)
110     char *dest;
111     const char *src;
112     size_t len;
113 {
114     size_t ret = strlen(src);
115 
116     if (len != 0) {
117 	if (ret < len)
118 	    (void) strcpy(dest, src);
119 	else {
120 	    (void) strncpy(dest, src, len - 1);
121 	    dest[len-1] = 0;
122 	}
123     }
124     return (ret);
125 }
126 
127 /*
128  * strlcat - like strcat/strncat, doesn't overflow destination buffer,
129  * always leaves destination null-terminated (for len > 0).
130  */
131 size_t
132 strlcat(dest, src, len)
133     char *dest;
134     const char *src;
135     size_t len;
136 {
137     size_t dlen = strlen(dest);
138 
139     return (dlen + strlcpy(dest + dlen, src, (len > dlen? len - dlen: 0)));
140 }
141 
142 
143 /*
144  * slprintf - format a message into a buffer.  Like sprintf except we
145  * also specify the length of the output buffer, and we handle %m
146  * (error message), %v (visible string), %q (quoted string), %t
147  * (current time), %I (IP address), %P (PPP packet), and %B (sequence
148  * of bytes) formats.  Doesn't do floating-point formats.  Returns the
149  * number of chars put into buf.
150  */
151 int
152 slprintf __V((char *buf, int buflen, const char *fmt, ...))
153 {
154     va_list args;
155     int n;
156 
157 #if defined(__STDC__)
158     va_start(args, fmt);
159 #else
160     char *buf;
161     int buflen;
162     const char *fmt;
163     va_start(args);
164     buf = va_arg(args, char *);
165     buflen = va_arg(args, int);
166     fmt = va_arg(args, const char *);
167 #endif
168     n = vslprintf(buf, buflen, fmt, args);
169     va_end(args);
170     return (n);
171 }
172 
173 /*
174  * Print to file or, if argument is NULL, to syslog at debug level.
175  */
176 int
177 flprintf __V((FILE *strptr, const char *fmt, ...))
178 {
179     va_list args;
180     int n;
181     char buf[1024], *bp, *nlp, *ebp;
182 
183 #if defined(__STDC__)
184     va_start(args, fmt);
185 #else
186     FILE *strptr;
187     const char *fmt;
188     va_start(args);
189     strptr = va_arg(args, FILE *);
190     fmt = va_arg(args, const char *);
191 #endif
192     n = vslprintf(buf, sizeof (buf), fmt, args);
193     va_end(args);
194     if (strptr == NULL) {
195 	bp = buf;
196 	ebp = buf + n;
197 	while (bp < ebp) {
198 	    if ((nlp = strchr(bp, '\n')) == NULL)
199 		nlp = ebp;
200 	    if (nlp > bp) {
201 		*nlp = '\0';
202 		syslog(LOG_DEBUG, "%s", bp);
203 	    }
204 	    bp = nlp + 1;
205 	}
206     } else {
207 	n = fwrite(buf, 1, n, strptr);
208     }
209     return (n);
210 }
211 
212 /*
213  * vslprintf - like slprintf, takes a va_list instead of a list of args.
214  */
215 #define OUTCHAR(c)	(buflen > 0? (--buflen, *buf++ = (c)): 0)
216 
217 int
218 vslprintf(buf, buflen, fmt, args)
219     char *buf;
220     int buflen;
221     const char *fmt;
222     va_list args;
223 {
224     int c, n, longs;
225     int width, prec, fillch;
226     int base, len, neg, quoted;
227 #ifdef SOL2
228     uint64_t val;
229     int64_t sval;
230 #else
231     unsigned long val;
232     long sval;
233 #endif
234     char *buf0, *mstr;
235     const char *f, *str;
236     unsigned char *p;
237     char num[32];	/* 2^64 is 20 chars decimal, 22 octal */
238     time_t t;
239     u_int32_t ip;
240     static const char hexchars[] = "0123456789abcdef";
241     struct buffer_info bufinfo;
242 
243     buf0 = buf;
244     --buflen;
245     while (buflen > 0) {
246 	for (f = fmt; *f != '%' && *f != 0; ++f)
247 	    ;
248 	if (f > fmt) {
249 	    len = f - fmt;
250 	    if (len > buflen)
251 		len = buflen;
252 	    (void) memcpy(buf, fmt, len);
253 	    buf += len;
254 	    buflen -= len;
255 	    fmt = f;
256 	}
257 	if (*fmt == 0)
258 	    break;
259 	c = *++fmt;
260 	width = 0;
261 	prec = -1;
262 	fillch = ' ';
263 	if (c == '0') {
264 	    fillch = '0';
265 	    c = *++fmt;
266 	}
267 	if (c == '*') {
268 	    width = va_arg(args, int);
269 	    c = *++fmt;
270 	} else {
271 	    while (isdigit(c)) {
272 		width = width * 10 + c - '0';
273 		c = *++fmt;
274 	    }
275 	}
276 	if (c == '.') {
277 	    c = *++fmt;
278 	    if (c == '*') {
279 		prec = va_arg(args, int);
280 		c = *++fmt;
281 	    } else {
282 		prec = 0;
283 		while (isdigit(c)) {
284 		    prec = prec * 10 + c - '0';
285 		    c = *++fmt;
286 		}
287 	    }
288 	}
289 	longs = 0;
290 	if (c == 'l') {
291 	    longs++;
292 	    c = *++fmt;
293 	    if (c == 'l') {
294 		longs++;
295 		c = *++fmt;
296 	    }
297 	}
298 	str = 0;
299 	base = 0;
300 	neg = 0;
301 	val = 0;
302 	++fmt;
303 	switch (c) {
304 	case 'u':
305 #ifdef SOL2
306 	    if (longs >= 2)
307 		val = va_arg(args, uint64_t);
308 	    else
309 #endif
310 	    if (longs > 0)
311 		val = va_arg(args, unsigned long);
312 	    else
313 		val = va_arg(args, unsigned int);
314 	    base = 10;
315 	    break;
316 	case 'd':
317 #ifdef SOL2
318 	    if (longs >= 2)
319 		sval = va_arg(args, int64_t);
320 	    else
321 #endif
322 	    if (longs > 0)
323 		sval = va_arg(args, long);
324 	    else
325 		sval = va_arg(args, int);
326 	    if (sval < 0) {
327 		neg = 1;
328 		val = -sval;
329 	    } else
330 		val = sval;
331 	    base = 10;
332 	    break;
333 	case 'o':
334 #ifdef SOL2
335 	    if (longs >= 2)
336 		val = va_arg(args, uint64_t);
337 	    else
338 #endif
339 	    if (longs > 0)
340 		val = va_arg(args, unsigned long);
341 	    else
342 		val = va_arg(args, unsigned int);
343 	    base = 8;
344 	    break;
345 	case 'x':
346 	case 'X':
347 #ifdef SOL2
348 	    if (longs >= 2)
349 		val = va_arg(args, uint64_t);
350 	    else
351 #endif
352 	    if (longs > 0)
353 		val = va_arg(args, unsigned long);
354 	    else
355 		val = va_arg(args, unsigned int);
356 	    base = 16;
357 	    break;
358 	case 'p':
359 	    val = (unsigned long) va_arg(args, void *);
360 	    base = 16;
361 	    neg = 2;
362 	    break;
363 	case 's':
364 	    str = va_arg(args, const char *);
365 	    break;
366 	case 'c':
367 	    num[0] = va_arg(args, int);
368 	    num[1] = 0;
369 	    str = num;
370 	    break;
371 	case 'm':
372 	    str = strerror(errno);
373 	    break;
374 	case 'I':
375 	    ip = va_arg(args, u_int32_t);
376 	    ip = ntohl(ip);
377 	    (void) slprintf(num, sizeof(num), "%d.%d.%d.%d", (ip >> 24) & 0xff,
378 		(ip >> 16) & 0xff, (ip >> 8) & 0xff, ip & 0xff);
379 	    str = num;
380 	    break;
381 	case 't':
382 	    (void) time(&t);
383 	    mstr = ctime(&t);
384 	    mstr += 4;		/* chop off the day name */
385 	    mstr[15] = 0;	/* chop off year and newline */
386 	    str = (const char *)mstr;
387 	    break;
388 	case 'v':		/* "visible" string */
389 	case 'q':		/* quoted string */
390 	    quoted = c == 'q';
391 	    p = va_arg(args, unsigned char *);
392 	    if (fillch == '0' && prec >= 0) {
393 		n = prec;
394 	    } else {
395 		n = strlen((char *)p);
396 		if (prec >= 0 && n > prec)
397 		    n = prec;
398 	    }
399 	    while (n > 0 && buflen > 0) {
400 		c = *p++;
401 		--n;
402 		if (!quoted && c >= 0x80) {
403 		    (void) OUTCHAR('M');
404 		    (void) OUTCHAR('-');
405 		    c -= 0x80;
406 		}
407 		if (quoted && (c == '"' || c == '\\'))
408 		    (void) OUTCHAR('\\');
409 		if (c < 0x20 || (0x7f <= c && c < 0xa0)) {
410 		    if (quoted) {
411 			(void) OUTCHAR('\\');
412 			switch (c) {
413 			case '\t':	(void) OUTCHAR('t');	break;
414 			case '\n':	(void) OUTCHAR('n');	break;
415 			case '\b':	(void) OUTCHAR('b');	break;
416 			case '\f':	(void) OUTCHAR('f');	break;
417 			default:
418 			    (void) OUTCHAR('x');
419 			    (void) OUTCHAR(hexchars[c >> 4]);
420 			    (void) OUTCHAR(hexchars[c & 0xf]);
421 			}
422 		    } else {
423 			if (c == '\t')
424 			    (void) OUTCHAR(c);
425 			else {
426 			    (void) OUTCHAR('^');
427 			    (void) OUTCHAR(c ^ 0x40);
428 			}
429 		    }
430 		} else
431 		    (void) OUTCHAR(c);
432 	    }
433 	    continue;
434 	case 'P':		/* print PPP packet */
435 	    bufinfo.ptr = buf;
436 	    bufinfo.len = buflen + 1;
437 	    p = va_arg(args, unsigned char *);
438 	    n = va_arg(args, int);
439 	    format_packet(p, n, vslp_printer, &bufinfo);
440 	    buf = bufinfo.ptr;
441 	    buflen = bufinfo.len - 1;
442 	    continue;
443 	case 'B':
444 	    p = va_arg(args, unsigned char *);
445 	    if ((n = prec) > width && width > 0)
446 		n = width;
447 	    /* For safety's sake */
448 	    if (n > 2000)
449 		    n = 2000;
450 	    while (--n >= 0) {
451 		c = *p++;
452 		if (fillch == ' ')
453 		    (void) OUTCHAR(' ');
454 		(void) OUTCHAR(hexchars[(c >> 4) & 0xf]);
455 		(void) OUTCHAR(hexchars[c & 0xf]);
456 	    }
457 	    if (prec > width && width > 0) {
458 		(void) OUTCHAR('.');
459 		(void) OUTCHAR('.');
460 		(void) OUTCHAR('.');
461 	    }
462 	    continue;
463 	default:
464 	    *buf++ = '%';
465 	    if (c != '%')
466 		--fmt;		/* so %z outputs %z etc. */
467 	    --buflen;
468 	    continue;
469 	}
470 	if (base != 0) {
471 	    mstr = num + sizeof(num);
472 	    *--mstr = 0;
473 	    while (mstr > num + neg) {
474 		*--mstr = hexchars[val % base];
475 		val = val / base;
476 		if (--prec <= 0 && val == 0)
477 		    break;
478 	    }
479 	    switch (neg) {
480 	    case 1:
481 		*--mstr = '-';
482 		break;
483 	    case 2:
484 		*--mstr = 'x';
485 		*--mstr = '0';
486 		break;
487 	    }
488 	    len = num + sizeof(num) - 1 - mstr;
489 	    str = (const char *)mstr;
490 	} else {
491 	    len = strlen(str);
492 	    if (prec >= 0 && len > prec)
493 		len = prec;
494 	}
495 	if (width > 0) {
496 	    if (width > buflen)
497 		width = buflen;
498 	    if ((n = width - len) > 0) {
499 		buflen -= n;
500 		for (; n > 0; --n)
501 		    *buf++ = fillch;
502 	    }
503 	}
504 	if (len > buflen)
505 	    len = buflen;
506 	(void) memcpy(buf, str, len);
507 	buf += len;
508 	buflen -= len;
509     }
510     *buf = 0;
511     return (buf - buf0);
512 }
513 
514 /*
515  * vslp_printer - used in processing a %P format
516  */
517 static void
518 vslp_printer __V((void *arg, const char *fmt, ...))
519 {
520     int n;
521     va_list pvar;
522     struct buffer_info *bi;
523 
524 #if defined(__STDC__)
525     va_start(pvar, fmt);
526 #else
527     void *arg;
528     const char *fmt;
529     va_start(pvar);
530     arg = va_arg(pvar, void *);
531     fmt = va_arg(pvar, const char *);
532 #endif
533 
534     bi = (struct buffer_info *) arg;
535     n = vslprintf(bi->ptr, bi->len, fmt, pvar);
536     va_end(pvar);
537 
538     bi->ptr += n;
539     bi->len -= n;
540 }
541 
542 /*
543  * log_packet - format a packet and log it.
544  */
545 
546 static char line[256];		/* line to be logged accumulated here */
547 static char *linep;
548 
549 void
550 log_packet(p, len, prefix, level)
551     u_char *p;
552     int len;
553     const char *prefix;
554     int level;
555 {
556     (void) strlcpy(line, prefix, sizeof(line));
557     linep = line + strlen(line);
558     format_packet(p, len, pr_log, (void *)level);
559     if (linep != line)
560 	syslog(level, "%s", line);
561 }
562 
563 /*
564  * format_packet - make a readable representation of a packet,
565  * calling `printer(arg, format, ...)' to output it.
566  */
567 static void
568 format_packet(p, len, printer, arg)
569     u_char *p;
570     int len;
571     void (*printer) __P((void *, const char *, ...));
572     void *arg;
573 {
574     int i, n;
575     u_short proto;
576     struct protent *protp;
577 
578     if (len >= PPP_HDRLEN && p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) {
579 	p += 2;
580 	GETSHORT(proto, p);
581 	len -= PPP_HDRLEN;
582 	for (i = 0; (protp = protocols[i]) != NULL; ++i)
583 	    if (proto == protp->protocol)
584 		break;
585 	if (protp != NULL) {
586 	    printer(arg, "[%s", protp->name);
587 	    n = (*protp->printpkt)(p, len, printer, arg);
588 	    printer(arg, "]");
589 	    p += n;
590 	    len -= n;
591 	} else {
592 	    for (i = 0; (protp = protocols[i]) != NULL; ++i)
593 		if (proto == (protp->protocol & ~0x8000))
594 		    break;
595 	    if (protp != NULL && protp->data_name != NULL) {
596 		printer(arg, "[%s data] %8.*B", protp->data_name, len, p);
597 		len = 0;
598 	    } else
599 		printer(arg, "[proto=0x%x]", proto);
600 	}
601     }
602 
603     printer(arg, "%32.*B", len, p);
604 }
605 
606 static void
607 pr_log __V((void *arg, const char *fmt, ...))
608 {
609     int n;
610     va_list pvar;
611     char buf[256];
612 
613 #if defined(__STDC__)
614     va_start(pvar, fmt);
615 #else
616     void *arg;
617     const char *fmt;
618     va_start(pvar);
619     arg = va_arg(pvar, void *);
620     fmt = va_arg(pvar, const char *);
621 #endif
622 
623     n = vslprintf(buf, sizeof(buf), fmt, pvar);
624     va_end(pvar);
625 
626     if (linep + n + 1 > line + sizeof(line)) {
627 	syslog((int)arg, "%s", line);
628 	linep = line;
629     }
630     (void) strlcpy(linep, buf, line + sizeof(line) - linep);
631     linep += n;
632 }
633 
634 /*
635  * print_string - print a readable representation of a string using
636  * printer.
637  */
638 void
639 print_string(p, len, printer, arg)
640     char *p;
641     int len;
642     void (*printer) __P((void *, const char *, ...));
643     void *arg;
644 {
645     int c;
646 
647     printer(arg, "\"");
648     for (; len > 0; --len) {
649 	c = *p++;
650 	if (isprint(c)) {
651 	    if (c == '\\' || c == '"')
652 		printer(arg, "\\");
653 	    printer(arg, "%c", c);
654 	} else {
655 	    switch (c) {
656 	    case '\n':
657 		printer(arg, "\\n");
658 		break;
659 	    case '\r':
660 		printer(arg, "\\r");
661 		break;
662 	    case '\t':
663 		printer(arg, "\\t");
664 		break;
665 	    default:
666 		printer(arg, "\\%.3o", c);
667 	    }
668 	}
669     }
670     printer(arg, "\"");
671 }
672 
673 /*
674  * logit - does the hard work for fatal et al.
675  */
676 static void
677 logit(level, fmt, args)
678     int level;
679     const char *fmt;
680     va_list args;
681 {
682     int n;
683     char buf[1024];
684 
685     n = vslprintf(buf, sizeof(buf), fmt, args);
686     syslog(level, "%s", buf);
687     if (log_to_fd >= 0 && (level != LOG_DEBUG || debug) &&
688 	(!early_log || log_to_specific_fd)) {
689 	if (buf[n-1] != '\n')
690 	    buf[n++] = '\n';
691 	if (write(log_to_fd, buf, n) != n)
692 	    log_to_fd = -1;
693     }
694 }
695 
696 /*
697  * fatal - log an error message and die horribly.
698  */
699 void
700 fatal __V((const char *fmt, ...))
701 {
702     va_list pvar;
703 
704 #if defined(__STDC__)
705     va_start(pvar, fmt);
706 #else
707     const char *fmt;
708     va_start(pvar);
709     fmt = va_arg(pvar, const char *);
710 #endif
711 
712     logit(LOG_ERR, fmt, pvar);
713     va_end(pvar);
714 
715     die(1);			/* as promised */
716 }
717 
718 /*
719  * error - log an error message.
720  */
721 void
722 error __V((const char *fmt, ...))
723 {
724     va_list pvar;
725 
726 #if defined(__STDC__)
727     va_start(pvar, fmt);
728 #else
729     const char *fmt;
730     va_start(pvar);
731     fmt = va_arg(pvar, const char *);
732 #endif
733 
734     logit(LOG_ERR, fmt, pvar);
735     va_end(pvar);
736 }
737 
738 /*
739  * warn - log a warning message.
740  */
741 void
742 warn __V((const char *fmt, ...))
743 {
744     va_list pvar;
745 
746 #if defined(__STDC__)
747     va_start(pvar, fmt);
748 #else
749     const char *fmt;
750     va_start(pvar);
751     fmt = va_arg(pvar, const char *);
752 #endif
753 
754     logit(LOG_WARNING, fmt, pvar);
755     va_end(pvar);
756 }
757 
758 /*
759  * notice - log a notice-level message.
760  */
761 void
762 notice __V((const char *fmt, ...))
763 {
764     va_list pvar;
765 
766 #if defined(__STDC__)
767     va_start(pvar, fmt);
768 #else
769     const char *fmt;
770     va_start(pvar);
771     fmt = va_arg(pvar, const char *);
772 #endif
773 
774     logit(LOG_NOTICE, fmt, pvar);
775     va_end(pvar);
776 }
777 
778 /*
779  * info - log an informational message.
780  */
781 void
782 info __V((const char *fmt, ...))
783 {
784     va_list pvar;
785 
786 #if defined(__STDC__)
787     va_start(pvar, fmt);
788 #else
789     const char *fmt;
790     va_start(pvar);
791     fmt = va_arg(pvar, const char *);
792 #endif
793 
794     logit(LOG_INFO, fmt, pvar);
795     va_end(pvar);
796 }
797 
798 /*
799  * dbglog - log a debug message.
800  */
801 void
802 dbglog __V((const char *fmt, ...))
803 {
804     va_list pvar;
805 
806 #if defined(__STDC__)
807     va_start(pvar, fmt);
808 #else
809     const char *fmt;
810     va_start(pvar);
811     fmt = va_arg(pvar, const char *);
812 #endif
813 
814     logit(LOG_DEBUG, fmt, pvar);
815     va_end(pvar);
816 }
817 
818 /*
819  * Code names for regular PPP messages.  Used by LCP and most NCPs,
820  * not used by authentication protocols.
821  */
822 const char *
823 code_name(int code, int shortflag)
824 {
825     static const char *codelist[] = {
826 	"Vendor-Extension", "Configure-Request", "Configure-Ack",
827 	"Configure-Nak", "Configure-Reject", "Terminate-Request",
828 	"Terminate-Ack", "Code-Reject", "Protocol-Reject",
829 	"Echo-Request", "Echo-Reply", "Discard-Request",
830 	"Identification", "Time-Remaining",
831 	"Reset-Request", "Reset-Ack"
832     };
833     static const char *shortcode[] = {
834 	"VendExt", "ConfReq", "ConfAck",
835 	"ConfNak", "ConfRej", "TermReq",
836 	"TermAck", "CodeRej", "ProtRej",
837 	"EchoReq", "EchoRep", "DiscReq",
838 	"Ident", "TimeRem",
839 	"ResetReq", "ResetAck"
840     };
841     static char msgbuf[64];
842 
843     if (code < 0 || code >= sizeof (codelist) / sizeof (*codelist)) {
844 	if (shortflag)
845 	    (void) slprintf(msgbuf, sizeof (msgbuf), "Code#%d", code);
846 	else
847 	    (void) slprintf(msgbuf, sizeof (msgbuf), "unknown code %d", code);
848 	return ((const char *)msgbuf);
849     }
850     return (shortflag ? shortcode[code] : codelist[code]);
851 }
852 
853 /* Procedures for locking the serial device using a lock file. */
854 #ifndef LOCK_DIR
855 #ifdef _linux_
856 #define LOCK_DIR	"/var/lock"
857 #else
858 #ifdef SVR4
859 #define LOCK_DIR	"/var/spool/locks"
860 #else
861 #define LOCK_DIR	"/var/spool/lock"
862 #endif
863 #endif
864 #endif /* LOCK_DIR */
865 
866 static char lock_file[MAXPATHLEN];
867 
868 /*
869  * lock - create a lock file for the named device
870  */
871 int
872 lock(dev)
873     char *dev;
874 {
875 #ifdef LOCKLIB
876     int result;
877 
878     result = mklock (dev, (void *) 0);
879     if (result == 0) {
880 	(void) strlcpy(lock_file, sizeof(lock_file), dev);
881 	return (0);
882     }
883 
884     if (result > 0)
885         notice("Device %s is locked by pid %d", dev, result);
886     else
887 	error("Can't create lock file %s", lock_file);
888     return (-1);
889 
890 #else /* LOCKLIB */
891 
892     char lock_buffer[12];
893     int fd, pid, n;
894 
895 #ifdef SVR4
896     struct stat sbuf;
897 
898     if (stat(dev, &sbuf) < 0) {
899 	error("Can't get device number for %s: %m", dev);
900 	return (-1);
901     }
902     if ((sbuf.st_mode & S_IFMT) != S_IFCHR) {
903 	error("Can't lock %s: not a character device", dev);
904 	return (-1);
905     }
906     (void) slprintf(lock_file, sizeof(lock_file), "%s/LK.%03d.%03d.%03d",
907 	     LOCK_DIR, major(sbuf.st_dev),
908 	     major(sbuf.st_rdev), minor(sbuf.st_rdev));
909 #else
910     char *p;
911 
912     if ((p = strrchr(dev, '/')) != NULL)
913 	dev = p + 1;
914     (void) slprintf(lock_file, sizeof(lock_file), "%s/LCK..%s", LOCK_DIR, dev);
915 #endif
916 
917     while ((fd = open(lock_file, O_EXCL | O_CREAT | O_RDWR, 0644)) < 0) {
918 	if (errno != EEXIST) {
919 	    error("Can't create lock file %s: %m", lock_file);
920 	    break;
921 	}
922 
923 	/* Read the lock file to find out who has the device locked. */
924 	fd = open(lock_file, O_RDONLY, 0);
925 	if (fd < 0) {
926 	    if (errno == ENOENT) /* This is just a timing problem. */
927 		continue;
928 	    error("Can't open existing lock file %s: %m", lock_file);
929 	    break;
930 	}
931 #ifndef LOCK_BINARY
932 	n = read(fd, lock_buffer, 11);
933 #else
934 	n = read(fd, &pid, sizeof(pid));
935 #endif /* LOCK_BINARY */
936 	(void) close(fd);
937 	fd = -1;
938 	if (n <= 0) {
939 	    error("Can't read pid from lock file %s", lock_file);
940 	    break;
941 	}
942 
943 	/* See if the process still exists. */
944 #ifndef LOCK_BINARY
945 	lock_buffer[n] = 0;
946 	pid = atoi(lock_buffer);
947 #endif /* LOCK_BINARY */
948 	if (pid == getpid())
949 	    return (1);		/* somebody else locked it for us */
950 	if (pid == 0
951 	    || (kill(pid, 0) == -1 && errno == ESRCH)) {
952 	    if (unlink (lock_file) == 0) {
953 		notice("Removed stale lock on %s (pid %d)", dev, pid);
954 		continue;
955 	    }
956 	    warn("Couldn't remove stale lock on %s", dev);
957 	} else
958 	    notice("Device %s is locked by pid %d", dev, pid);
959 	break;
960     }
961 
962     if (fd < 0) {
963 	lock_file[0] = 0;
964 	return (-1);
965     }
966 
967     pid = getpid();
968 #ifndef LOCK_BINARY
969     (void) slprintf(lock_buffer, sizeof(lock_buffer), "%10d\n", pid);
970     (void) write (fd, lock_buffer, 11);
971 #else
972     (void) write(fd, &pid, sizeof (pid));
973 #endif
974     (void) close(fd);
975     return (0);
976 
977 #endif
978 }
979 
980 /*
981  * relock - called to update our lockfile when we are about to detach,
982  * thus changing our pid (we fork, the child carries on, and the parent dies).
983  * Note that this is called by the parent, with pid equal to the pid
984  * of the child.  This avoids a potential race which would exist if
985  * we had the child rewrite the lockfile (the parent might die first,
986  * and another process could think the lock was stale if it checked
987  * between when the parent died and the child rewrote the lockfile).
988  */
989 int
990 relock(pid)
991     int pid;
992 {
993 #ifdef LOCKLIB
994     /* XXX is there a way to do this? */
995     return (-1);
996 #else /* LOCKLIB */
997 
998     int fd;
999     char lock_buffer[12];
1000 
1001     if (lock_file[0] == 0)
1002 	return (-1);
1003     fd = open(lock_file, O_WRONLY, 0);
1004     if (fd < 0) {
1005 	error("Couldn't reopen lock file %s: %m", lock_file);
1006 	lock_file[0] = 0;
1007 	return (-1);
1008     }
1009 
1010 #ifndef LOCK_BINARY
1011     (void) slprintf(lock_buffer, sizeof(lock_buffer), "%10d\n", pid);
1012     (void) write (fd, lock_buffer, 11);
1013 #else
1014     (void) write(fd, &pid, sizeof(pid));
1015 #endif /* LOCK_BINARY */
1016     (void) close(fd);
1017     return (0);
1018 
1019 #endif /* LOCKLIB */
1020 }
1021 
1022 /*
1023  * unlock - remove our lockfile
1024  */
1025 void
1026 unlock()
1027 {
1028     if (lock_file[0]) {
1029 #ifdef LOCKLIB
1030 	(void) rmlock(lock_file, (void *) 0);
1031 #else
1032 	(void) unlink(lock_file);
1033 #endif
1034 	lock_file[0] = 0;
1035     }
1036 }
1037 
1038 const char *
1039 signal_name(int signum)
1040 {
1041 #if defined(SOL2) || defined(__linux__) || defined(_linux_)
1042     const char *cp;
1043 
1044     if ((cp = strsignal(signum)) != NULL)
1045 	return (cp);
1046 #else
1047     extern char *sys_siglist[];
1048     extern int sys_nsig;
1049 
1050     if (signum >= 0 && signum < sys_nsig && sys_siglist[signum] != NULL)
1051 	return (sys_siglist[signum]);
1052 #endif
1053     return ("??");
1054 }
1055