1 /*
2  * utils.c - various utility functions used in pppd.
3  *
4  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
5  * Use is subject to license terms.
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  * slprintf - format a message into a buffer.  Like sprintf except we
106  * also specify the length of the output buffer, and we handle %m
107  * (error message), %v (visible string), %q (quoted string), %t
108  * (current time), %I (IP address), %P (PPP packet), and %B (sequence
109  * of bytes) formats.  Doesn't do floating-point formats.  Returns the
110  * number of chars put into buf.
111  */
112 int
113 slprintf __V((char *buf, int buflen, const char *fmt, ...))
114 {
115     va_list args;
116     int n;
117 
118 #if defined(__STDC__)
119     va_start(args, fmt);
120 #else
121     char *buf;
122     int buflen;
123     const char *fmt;
124     va_start(args);
125     buf = va_arg(args, char *);
126     buflen = va_arg(args, int);
127     fmt = va_arg(args, const char *);
128 #endif
129     n = vslprintf(buf, buflen, fmt, args);
130     va_end(args);
131     return (n);
132 }
133 
134 /*
135  * Print to file or, if argument is NULL, to syslog at debug level.
136  */
137 int
138 flprintf __V((FILE *strptr, const char *fmt, ...))
139 {
140     va_list args;
141     int n;
142     char buf[1024], *bp, *nlp, *ebp;
143 
144 #if defined(__STDC__)
145     va_start(args, fmt);
146 #else
147     FILE *strptr;
148     const char *fmt;
149     va_start(args);
150     strptr = va_arg(args, FILE *);
151     fmt = va_arg(args, const char *);
152 #endif
153     n = vslprintf(buf, sizeof (buf), fmt, args);
154     va_end(args);
155     if (strptr == NULL) {
156 	bp = buf;
157 	ebp = buf + n;
158 	while (bp < ebp) {
159 	    if ((nlp = strchr(bp, '\n')) == NULL)
160 		nlp = ebp;
161 	    if (nlp > bp) {
162 		*nlp = '\0';
163 		syslog(LOG_DEBUG, "%s", bp);
164 	    }
165 	    bp = nlp + 1;
166 	}
167     } else {
168 	n = fwrite(buf, 1, n, strptr);
169     }
170     return (n);
171 }
172 
173 /*
174  * vslprintf - like slprintf, takes a va_list instead of a list of args.
175  */
176 #define OUTCHAR(c)	(buflen > 0? (--buflen, *buf++ = (c)): 0)
177 
178 int
179 vslprintf(buf, buflen, fmt, args)
180     char *buf;
181     int buflen;
182     const char *fmt;
183     va_list args;
184 {
185     int c, n, longs;
186     int width, prec, fillch;
187     int base, len, neg, quoted;
188 #ifdef SOL2
189     uint64_t val;
190     int64_t sval;
191 #else
192     unsigned long val;
193     long sval;
194 #endif
195     char *buf0, *mstr;
196     const char *f, *str;
197     unsigned char *p;
198     char num[32];	/* 2^64 is 20 chars decimal, 22 octal */
199     time_t t;
200     u_int32_t ip;
201     static const char hexchars[] = "0123456789abcdef";
202     struct buffer_info bufinfo;
203 
204     buf0 = buf;
205     --buflen;
206     while (buflen > 0) {
207 	for (f = fmt; *f != '%' && *f != 0; ++f)
208 	    ;
209 	if (f > fmt) {
210 	    len = f - fmt;
211 	    if (len > buflen)
212 		len = buflen;
213 	    (void) memcpy(buf, fmt, len);
214 	    buf += len;
215 	    buflen -= len;
216 	    fmt = f;
217 	}
218 	if (*fmt == 0)
219 	    break;
220 	c = *++fmt;
221 	width = 0;
222 	prec = -1;
223 	fillch = ' ';
224 	if (c == '0') {
225 	    fillch = '0';
226 	    c = *++fmt;
227 	}
228 	if (c == '*') {
229 	    width = va_arg(args, int);
230 	    c = *++fmt;
231 	} else {
232 	    while (isdigit(c)) {
233 		width = width * 10 + c - '0';
234 		c = *++fmt;
235 	    }
236 	}
237 	if (c == '.') {
238 	    c = *++fmt;
239 	    if (c == '*') {
240 		prec = va_arg(args, int);
241 		c = *++fmt;
242 	    } else {
243 		prec = 0;
244 		while (isdigit(c)) {
245 		    prec = prec * 10 + c - '0';
246 		    c = *++fmt;
247 		}
248 	    }
249 	}
250 	longs = 0;
251 	if (c == 'l') {
252 	    longs++;
253 	    c = *++fmt;
254 	    if (c == 'l') {
255 		longs++;
256 		c = *++fmt;
257 	    }
258 	}
259 	str = 0;
260 	base = 0;
261 	neg = 0;
262 	val = 0;
263 	++fmt;
264 	switch (c) {
265 	case 'u':
266 #ifdef SOL2
267 	    if (longs >= 2)
268 		val = va_arg(args, uint64_t);
269 	    else
270 #endif
271 	    if (longs > 0)
272 		val = va_arg(args, unsigned long);
273 	    else
274 		val = va_arg(args, unsigned int);
275 	    base = 10;
276 	    break;
277 	case 'd':
278 #ifdef SOL2
279 	    if (longs >= 2)
280 		sval = va_arg(args, int64_t);
281 	    else
282 #endif
283 	    if (longs > 0)
284 		sval = va_arg(args, long);
285 	    else
286 		sval = va_arg(args, int);
287 	    if (sval < 0) {
288 		neg = 1;
289 		val = -sval;
290 	    } else
291 		val = sval;
292 	    base = 10;
293 	    break;
294 	case 'o':
295 #ifdef SOL2
296 	    if (longs >= 2)
297 		val = va_arg(args, uint64_t);
298 	    else
299 #endif
300 	    if (longs > 0)
301 		val = va_arg(args, unsigned long);
302 	    else
303 		val = va_arg(args, unsigned int);
304 	    base = 8;
305 	    break;
306 	case 'x':
307 	case 'X':
308 #ifdef SOL2
309 	    if (longs >= 2)
310 		val = va_arg(args, uint64_t);
311 	    else
312 #endif
313 	    if (longs > 0)
314 		val = va_arg(args, unsigned long);
315 	    else
316 		val = va_arg(args, unsigned int);
317 	    base = 16;
318 	    break;
319 	case 'p':
320 	    val = (unsigned long) va_arg(args, void *);
321 	    base = 16;
322 	    neg = 2;
323 	    break;
324 	case 's':
325 	    str = va_arg(args, const char *);
326 	    break;
327 	case 'c':
328 	    num[0] = va_arg(args, int);
329 	    num[1] = 0;
330 	    str = num;
331 	    break;
332 	case 'm':
333 	    str = strerror(errno);
334 	    break;
335 	case 'I':
336 	    ip = va_arg(args, u_int32_t);
337 	    ip = ntohl(ip);
338 	    (void) slprintf(num, sizeof(num), "%d.%d.%d.%d", (ip >> 24) & 0xff,
339 		(ip >> 16) & 0xff, (ip >> 8) & 0xff, ip & 0xff);
340 	    str = num;
341 	    break;
342 	case 't':
343 	    (void) time(&t);
344 	    mstr = ctime(&t);
345 	    mstr += 4;		/* chop off the day name */
346 	    mstr[15] = 0;	/* chop off year and newline */
347 	    str = (const char *)mstr;
348 	    break;
349 	case 'v':		/* "visible" string */
350 	case 'q':		/* quoted string */
351 	    quoted = c == 'q';
352 	    p = va_arg(args, unsigned char *);
353 	    if (fillch == '0' && prec >= 0) {
354 		n = prec;
355 	    } else {
356 		n = strlen((char *)p);
357 		if (prec >= 0 && n > prec)
358 		    n = prec;
359 	    }
360 	    while (n > 0 && buflen > 0) {
361 		c = *p++;
362 		--n;
363 		if (!quoted && c >= 0x80) {
364 		    (void) OUTCHAR('M');
365 		    (void) OUTCHAR('-');
366 		    c -= 0x80;
367 		}
368 		if (quoted && (c == '"' || c == '\\'))
369 		    (void) OUTCHAR('\\');
370 		if (c < 0x20 || (0x7f <= c && c < 0xa0)) {
371 		    if (quoted) {
372 			(void) OUTCHAR('\\');
373 			switch (c) {
374 			case '\t':	(void) OUTCHAR('t');	break;
375 			case '\n':	(void) OUTCHAR('n');	break;
376 			case '\b':	(void) OUTCHAR('b');	break;
377 			case '\f':	(void) OUTCHAR('f');	break;
378 			default:
379 			    (void) OUTCHAR('x');
380 			    (void) OUTCHAR(hexchars[c >> 4]);
381 			    (void) OUTCHAR(hexchars[c & 0xf]);
382 			}
383 		    } else {
384 			if (c == '\t')
385 			    (void) OUTCHAR(c);
386 			else {
387 			    (void) OUTCHAR('^');
388 			    (void) OUTCHAR(c ^ 0x40);
389 			}
390 		    }
391 		} else
392 		    (void) OUTCHAR(c);
393 	    }
394 	    continue;
395 	case 'P':		/* print PPP packet */
396 	    bufinfo.ptr = buf;
397 	    bufinfo.len = buflen + 1;
398 	    p = va_arg(args, unsigned char *);
399 	    n = va_arg(args, int);
400 	    format_packet(p, n, vslp_printer, &bufinfo);
401 	    buf = bufinfo.ptr;
402 	    buflen = bufinfo.len - 1;
403 	    continue;
404 	case 'B':
405 	    p = va_arg(args, unsigned char *);
406 	    if ((n = prec) > width && width > 0)
407 		n = width;
408 	    /* For safety's sake */
409 	    if (n > 2000)
410 		    n = 2000;
411 	    while (--n >= 0) {
412 		c = *p++;
413 		if (fillch == ' ')
414 		    (void) OUTCHAR(' ');
415 		(void) OUTCHAR(hexchars[(c >> 4) & 0xf]);
416 		(void) OUTCHAR(hexchars[c & 0xf]);
417 	    }
418 	    if (prec > width && width > 0) {
419 		(void) OUTCHAR('.');
420 		(void) OUTCHAR('.');
421 		(void) OUTCHAR('.');
422 	    }
423 	    continue;
424 	default:
425 	    *buf++ = '%';
426 	    if (c != '%')
427 		--fmt;		/* so %z outputs %z etc. */
428 	    --buflen;
429 	    continue;
430 	}
431 	if (base != 0) {
432 	    mstr = num + sizeof(num);
433 	    *--mstr = 0;
434 	    while (mstr > num + neg) {
435 		*--mstr = hexchars[val % base];
436 		val = val / base;
437 		if (--prec <= 0 && val == 0)
438 		    break;
439 	    }
440 	    switch (neg) {
441 	    case 1:
442 		*--mstr = '-';
443 		break;
444 	    case 2:
445 		*--mstr = 'x';
446 		*--mstr = '0';
447 		break;
448 	    }
449 	    len = num + sizeof(num) - 1 - mstr;
450 	    str = (const char *)mstr;
451 	} else {
452 	    len = strlen(str);
453 	    if (prec >= 0 && len > prec)
454 		len = prec;
455 	}
456 	if (width > 0) {
457 	    if (width > buflen)
458 		width = buflen;
459 	    if ((n = width - len) > 0) {
460 		buflen -= n;
461 		for (; n > 0; --n)
462 		    *buf++ = fillch;
463 	    }
464 	}
465 	if (len > buflen)
466 	    len = buflen;
467 	(void) memcpy(buf, str, len);
468 	buf += len;
469 	buflen -= len;
470     }
471     *buf = 0;
472     return (buf - buf0);
473 }
474 
475 /*
476  * vslp_printer - used in processing a %P format
477  */
478 static void
479 vslp_printer __V((void *arg, const char *fmt, ...))
480 {
481     int n;
482     va_list pvar;
483     struct buffer_info *bi;
484 
485 #if defined(__STDC__)
486     va_start(pvar, fmt);
487 #else
488     void *arg;
489     const char *fmt;
490     va_start(pvar);
491     arg = va_arg(pvar, void *);
492     fmt = va_arg(pvar, const char *);
493 #endif
494 
495     bi = (struct buffer_info *) arg;
496     n = vslprintf(bi->ptr, bi->len, fmt, pvar);
497     va_end(pvar);
498 
499     bi->ptr += n;
500     bi->len -= n;
501 }
502 
503 /*
504  * log_packet - format a packet and log it.
505  */
506 
507 static char line[256];		/* line to be logged accumulated here */
508 static char *linep;
509 
510 void
511 log_packet(p, len, prefix, level)
512     u_char *p;
513     int len;
514     const char *prefix;
515     int level;
516 {
517     (void) strlcpy(line, prefix, sizeof(line));
518     linep = line + strlen(line);
519     format_packet(p, len, pr_log, (void *)level);
520     if (linep != line)
521 	syslog(level, "%s", line);
522 }
523 
524 /*
525  * format_packet - make a readable representation of a packet,
526  * calling `printer(arg, format, ...)' to output it.
527  */
528 static void
529 format_packet(p, len, printer, arg)
530     u_char *p;
531     int len;
532     void (*printer) __P((void *, const char *, ...));
533     void *arg;
534 {
535     int i, n;
536     u_short proto;
537     struct protent *protp;
538 
539     if (len >= PPP_HDRLEN && p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) {
540 	p += 2;
541 	GETSHORT(proto, p);
542 	len -= PPP_HDRLEN;
543 	for (i = 0; (protp = protocols[i]) != NULL; ++i)
544 	    if (proto == protp->protocol)
545 		break;
546 	if (protp != NULL) {
547 	    printer(arg, "[%s", protp->name);
548 	    n = (*protp->printpkt)(p, len, printer, arg);
549 	    printer(arg, "]");
550 	    p += n;
551 	    len -= n;
552 	} else {
553 	    for (i = 0; (protp = protocols[i]) != NULL; ++i)
554 		if (proto == (protp->protocol & ~0x8000))
555 		    break;
556 	    if (protp != NULL && protp->data_name != NULL) {
557 		printer(arg, "[%s data] %8.*B", protp->data_name, len, p);
558 		len = 0;
559 	    } else
560 		printer(arg, "[proto=0x%x]", proto);
561 	}
562     }
563 
564     printer(arg, "%32.*B", len, p);
565 }
566 
567 static void
568 pr_log __V((void *arg, const char *fmt, ...))
569 {
570     int n;
571     va_list pvar;
572     char buf[256];
573 
574 #if defined(__STDC__)
575     va_start(pvar, fmt);
576 #else
577     void *arg;
578     const char *fmt;
579     va_start(pvar);
580     arg = va_arg(pvar, void *);
581     fmt = va_arg(pvar, const char *);
582 #endif
583 
584     n = vslprintf(buf, sizeof(buf), fmt, pvar);
585     va_end(pvar);
586 
587     if (linep + n + 1 > line + sizeof(line)) {
588 	syslog((int)arg, "%s", line);
589 	linep = line;
590     }
591     (void) strlcpy(linep, buf, line + sizeof(line) - linep);
592     linep += n;
593 }
594 
595 /*
596  * print_string - print a readable representation of a string using
597  * printer.
598  */
599 void
600 print_string(p, len, printer, arg)
601     char *p;
602     int len;
603     void (*printer) __P((void *, const char *, ...));
604     void *arg;
605 {
606     int c;
607 
608     printer(arg, "\"");
609     for (; len > 0; --len) {
610 	c = *p++;
611 	if (isprint(c)) {
612 	    if (c == '\\' || c == '"')
613 		printer(arg, "\\");
614 	    printer(arg, "%c", c);
615 	} else {
616 	    switch (c) {
617 	    case '\n':
618 		printer(arg, "\\n");
619 		break;
620 	    case '\r':
621 		printer(arg, "\\r");
622 		break;
623 	    case '\t':
624 		printer(arg, "\\t");
625 		break;
626 	    default:
627 		printer(arg, "\\%.3o", c);
628 	    }
629 	}
630     }
631     printer(arg, "\"");
632 }
633 
634 /*
635  * logit - does the hard work for fatal et al.
636  */
637 static void
638 logit(level, fmt, args)
639     int level;
640     const char *fmt;
641     va_list args;
642 {
643     int n;
644     char buf[1024];
645 
646     n = vslprintf(buf, sizeof(buf), fmt, args);
647     syslog(level, "%s", buf);
648     if (log_to_fd >= 0 && (level != LOG_DEBUG || debug) &&
649 	(!early_log || log_to_specific_fd)) {
650 	if (buf[n-1] != '\n')
651 	    buf[n++] = '\n';
652 	if (write(log_to_fd, buf, n) != n)
653 	    log_to_fd = -1;
654     }
655 }
656 
657 /*
658  * fatal - log an error message and die horribly.
659  */
660 void
661 fatal __V((const char *fmt, ...))
662 {
663     va_list pvar;
664 
665 #if defined(__STDC__)
666     va_start(pvar, fmt);
667 #else
668     const char *fmt;
669     va_start(pvar);
670     fmt = va_arg(pvar, const char *);
671 #endif
672 
673     logit(LOG_ERR, fmt, pvar);
674     va_end(pvar);
675 
676     die(1);			/* as promised */
677 }
678 
679 /*
680  * error - log an error message.
681  */
682 void
683 error __V((const char *fmt, ...))
684 {
685     va_list pvar;
686 
687 #if defined(__STDC__)
688     va_start(pvar, fmt);
689 #else
690     const char *fmt;
691     va_start(pvar);
692     fmt = va_arg(pvar, const char *);
693 #endif
694 
695     logit(LOG_ERR, fmt, pvar);
696     va_end(pvar);
697 }
698 
699 /*
700  * warn - log a warning message.
701  */
702 void
703 warn __V((const char *fmt, ...))
704 {
705     va_list pvar;
706 
707 #if defined(__STDC__)
708     va_start(pvar, fmt);
709 #else
710     const char *fmt;
711     va_start(pvar);
712     fmt = va_arg(pvar, const char *);
713 #endif
714 
715     logit(LOG_WARNING, fmt, pvar);
716     va_end(pvar);
717 }
718 
719 /*
720  * notice - log a notice-level message.
721  */
722 void
723 notice __V((const char *fmt, ...))
724 {
725     va_list pvar;
726 
727 #if defined(__STDC__)
728     va_start(pvar, fmt);
729 #else
730     const char *fmt;
731     va_start(pvar);
732     fmt = va_arg(pvar, const char *);
733 #endif
734 
735     logit(LOG_NOTICE, fmt, pvar);
736     va_end(pvar);
737 }
738 
739 /*
740  * info - log an informational message.
741  */
742 void
743 info __V((const char *fmt, ...))
744 {
745     va_list pvar;
746 
747 #if defined(__STDC__)
748     va_start(pvar, fmt);
749 #else
750     const char *fmt;
751     va_start(pvar);
752     fmt = va_arg(pvar, const char *);
753 #endif
754 
755     logit(LOG_INFO, fmt, pvar);
756     va_end(pvar);
757 }
758 
759 /*
760  * dbglog - log a debug message.
761  */
762 void
763 dbglog __V((const char *fmt, ...))
764 {
765     va_list pvar;
766 
767 #if defined(__STDC__)
768     va_start(pvar, fmt);
769 #else
770     const char *fmt;
771     va_start(pvar);
772     fmt = va_arg(pvar, const char *);
773 #endif
774 
775     logit(LOG_DEBUG, fmt, pvar);
776     va_end(pvar);
777 }
778 
779 /*
780  * Code names for regular PPP messages.  Used by LCP and most NCPs,
781  * not used by authentication protocols.
782  */
783 const char *
784 code_name(int code, int shortflag)
785 {
786     static const char *codelist[] = {
787 	"Vendor-Extension", "Configure-Request", "Configure-Ack",
788 	"Configure-Nak", "Configure-Reject", "Terminate-Request",
789 	"Terminate-Ack", "Code-Reject", "Protocol-Reject",
790 	"Echo-Request", "Echo-Reply", "Discard-Request",
791 	"Identification", "Time-Remaining",
792 	"Reset-Request", "Reset-Ack"
793     };
794     static const char *shortcode[] = {
795 	"VendExt", "ConfReq", "ConfAck",
796 	"ConfNak", "ConfRej", "TermReq",
797 	"TermAck", "CodeRej", "ProtRej",
798 	"EchoReq", "EchoRep", "DiscReq",
799 	"Ident", "TimeRem",
800 	"ResetReq", "ResetAck"
801     };
802     static char msgbuf[64];
803 
804     if (code < 0 || code >= sizeof (codelist) / sizeof (*codelist)) {
805 	if (shortflag)
806 	    (void) slprintf(msgbuf, sizeof (msgbuf), "Code#%d", code);
807 	else
808 	    (void) slprintf(msgbuf, sizeof (msgbuf), "unknown code %d", code);
809 	return ((const char *)msgbuf);
810     }
811     return (shortflag ? shortcode[code] : codelist[code]);
812 }
813 
814 /* Procedures for locking the serial device using a lock file. */
815 #ifndef LOCK_DIR
816 #ifdef _linux_
817 #define LOCK_DIR	"/var/lock"
818 #else
819 #ifdef SVR4
820 #define LOCK_DIR	"/var/spool/locks"
821 #else
822 #define LOCK_DIR	"/var/spool/lock"
823 #endif
824 #endif
825 #endif /* LOCK_DIR */
826 
827 static char lock_file[MAXPATHLEN];
828 
829 /*
830  * lock - create a lock file for the named device
831  */
832 int
833 lock(dev)
834     char *dev;
835 {
836 #ifdef LOCKLIB
837     int result;
838 
839     result = mklock (dev, (void *) 0);
840     if (result == 0) {
841 	(void) strlcpy(lock_file, sizeof(lock_file), dev);
842 	return (0);
843     }
844 
845     if (result > 0)
846         notice("Device %s is locked by pid %d", dev, result);
847     else
848 	error("Can't create lock file %s", lock_file);
849     return (-1);
850 
851 #else /* LOCKLIB */
852 
853     char lock_buffer[12];
854     int fd, pid, n;
855 
856 #ifdef SVR4
857     struct stat sbuf;
858 
859     if (stat(dev, &sbuf) < 0) {
860 	error("Can't get device number for %s: %m", dev);
861 	return (-1);
862     }
863     if ((sbuf.st_mode & S_IFMT) != S_IFCHR) {
864 	error("Can't lock %s: not a character device", dev);
865 	return (-1);
866     }
867     (void) slprintf(lock_file, sizeof(lock_file), "%s/LK.%03d.%03d.%03d",
868 	     LOCK_DIR, major(sbuf.st_dev),
869 	     major(sbuf.st_rdev), minor(sbuf.st_rdev));
870 #else
871     char *p;
872 
873     if ((p = strrchr(dev, '/')) != NULL)
874 	dev = p + 1;
875     (void) slprintf(lock_file, sizeof(lock_file), "%s/LCK..%s", LOCK_DIR, dev);
876 #endif
877 
878     while ((fd = open(lock_file, O_EXCL | O_CREAT | O_RDWR, 0644)) < 0) {
879 	if (errno != EEXIST) {
880 	    error("Can't create lock file %s: %m", lock_file);
881 	    break;
882 	}
883 
884 	/* Read the lock file to find out who has the device locked. */
885 	fd = open(lock_file, O_RDONLY, 0);
886 	if (fd < 0) {
887 	    if (errno == ENOENT) /* This is just a timing problem. */
888 		continue;
889 	    error("Can't open existing lock file %s: %m", lock_file);
890 	    break;
891 	}
892 #ifndef LOCK_BINARY
893 	n = read(fd, lock_buffer, 11);
894 #else
895 	n = read(fd, &pid, sizeof(pid));
896 #endif /* LOCK_BINARY */
897 	(void) close(fd);
898 	fd = -1;
899 	if (n <= 0) {
900 	    error("Can't read pid from lock file %s", lock_file);
901 	    break;
902 	}
903 
904 	/* See if the process still exists. */
905 #ifndef LOCK_BINARY
906 	lock_buffer[n] = 0;
907 	pid = atoi(lock_buffer);
908 #endif /* LOCK_BINARY */
909 	if (pid == getpid())
910 	    return (1);		/* somebody else locked it for us */
911 	if (pid == 0
912 	    || (kill(pid, 0) == -1 && errno == ESRCH)) {
913 	    if (unlink (lock_file) == 0) {
914 		notice("Removed stale lock on %s (pid %d)", dev, pid);
915 		continue;
916 	    }
917 	    warn("Couldn't remove stale lock on %s", dev);
918 	} else
919 	    notice("Device %s is locked by pid %d", dev, pid);
920 	break;
921     }
922 
923     if (fd < 0) {
924 	lock_file[0] = 0;
925 	return (-1);
926     }
927 
928     pid = getpid();
929 #ifndef LOCK_BINARY
930     (void) slprintf(lock_buffer, sizeof(lock_buffer), "%10d\n", pid);
931     (void) write (fd, lock_buffer, 11);
932 #else
933     (void) write(fd, &pid, sizeof (pid));
934 #endif
935     (void) close(fd);
936     return (0);
937 
938 #endif
939 }
940 
941 /*
942  * relock - called to update our lockfile when we are about to detach,
943  * thus changing our pid (we fork, the child carries on, and the parent dies).
944  * Note that this is called by the parent, with pid equal to the pid
945  * of the child.  This avoids a potential race which would exist if
946  * we had the child rewrite the lockfile (the parent might die first,
947  * and another process could think the lock was stale if it checked
948  * between when the parent died and the child rewrote the lockfile).
949  */
950 int
951 relock(pid)
952     int pid;
953 {
954 #ifdef LOCKLIB
955     /* XXX is there a way to do this? */
956     return (-1);
957 #else /* LOCKLIB */
958 
959     int fd;
960     char lock_buffer[12];
961 
962     if (lock_file[0] == 0)
963 	return (-1);
964     fd = open(lock_file, O_WRONLY, 0);
965     if (fd < 0) {
966 	error("Couldn't reopen lock file %s: %m", lock_file);
967 	lock_file[0] = 0;
968 	return (-1);
969     }
970 
971 #ifndef LOCK_BINARY
972     (void) slprintf(lock_buffer, sizeof(lock_buffer), "%10d\n", pid);
973     (void) write (fd, lock_buffer, 11);
974 #else
975     (void) write(fd, &pid, sizeof(pid));
976 #endif /* LOCK_BINARY */
977     (void) close(fd);
978     return (0);
979 
980 #endif /* LOCKLIB */
981 }
982 
983 /*
984  * unlock - remove our lockfile
985  */
986 void
987 unlock()
988 {
989     if (lock_file[0]) {
990 #ifdef LOCKLIB
991 	(void) rmlock(lock_file, (void *) 0);
992 #else
993 	(void) unlink(lock_file);
994 #endif
995 	lock_file[0] = 0;
996     }
997 }
998 
999 const char *
1000 signal_name(int signum)
1001 {
1002 #if defined(SOL2) || defined(__linux__) || defined(_linux_)
1003     const char *cp;
1004 
1005     if ((cp = strsignal(signum)) != NULL)
1006 	return (cp);
1007 #else
1008     extern char *sys_siglist[];
1009     extern int sys_nsig;
1010 
1011     if (signum >= 0 && signum < sys_nsig && sys_siglist[signum] != NULL)
1012 	return (sys_siglist[signum]);
1013 #endif
1014     return ("??");
1015 }
1016