xref: /illumos-gate/usr/src/cmd/cmd-inet/usr.bin/pppd/utils.c (revision 8119dad84d6416f13557b0ba8e2aaf9064cbcfd3)
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 #ifdef __linux__
35 #define	_GNU_SOURCE
36 #endif
37 #include <stdio.h>
38 #include <ctype.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <unistd.h>
42 #include <signal.h>
43 #include <errno.h>
44 #include <fcntl.h>
45 #include <syslog.h>
46 #include <netdb.h>
47 #include <utmp.h>
48 #include <pwd.h>
49 #include <sys/param.h>
50 #include <sys/types.h>
51 #include <sys/wait.h>
52 #include <sys/time.h>
53 #include <sys/resource.h>
54 #include <sys/stat.h>
55 #include <sys/socket.h>
56 #include <netinet/in.h>
57 #ifdef SVR4
58 #include <sys/mkdev.h>
59 #endif
60 
61 #include "pppd.h"
62 
63 #if defined(SUNOS4)
64 extern char *strerror();
65 #endif
66 
67 /* Don't log to stdout until we're sure it's ok to do so. */
68 bool early_log = 1;
69 
70 static void pr_log __P((void *, const char *, ...));
71 static void logit __P((int, const char *, va_list));
72 static void vslp_printer __P((void *, const char *, ...));
73 static void format_packet __P((u_char *, int,
74     void (*) (void *, const char *, ...), void *));
75 
76 struct buffer_info {
77     char *ptr;
78     int len;
79 };
80 
81 /*
82  * strllen - like strlen, but doesn't run past end of input.
83  */
84 size_t
85 strllen(str, len)
86     const char *str;
87     size_t len;
88 {
89     size_t ret;
90 
91     for (ret = 0; ret < len; ret++)
92 	if (*str++ == '\0')
93 	    break;
94     return (ret);
95 }
96 
97 /*
98  * slprintf - format a message into a buffer.  Like sprintf except we
99  * also specify the length of the output buffer, and we handle %m
100  * (error message), %v (visible string), %q (quoted string), %t
101  * (current time), %I (IP address), %P (PPP packet), and %B (sequence
102  * of bytes) formats.  Doesn't do floating-point formats.  Returns the
103  * number of chars put into buf.
104  */
105 int
106 slprintf __V((char *buf, int buflen, const char *fmt, ...))
107 {
108     va_list args;
109     int n;
110 
111 #if defined(__STDC__)
112     va_start(args, fmt);
113 #else
114     char *buf;
115     int buflen;
116     const char *fmt;
117     va_start(args);
118     buf = va_arg(args, char *);
119     buflen = va_arg(args, int);
120     fmt = va_arg(args, const char *);
121 #endif
122     n = vslprintf(buf, buflen, fmt, args);
123     va_end(args);
124     return (n);
125 }
126 
127 /*
128  * Print to file or, if argument is NULL, to syslog at debug level.
129  */
130 int
131 flprintf __V((FILE *strptr, const char *fmt, ...))
132 {
133     va_list args;
134     int n;
135     char buf[1024], *bp, *nlp, *ebp;
136 
137 #if defined(__STDC__)
138     va_start(args, fmt);
139 #else
140     FILE *strptr;
141     const char *fmt;
142     va_start(args);
143     strptr = va_arg(args, FILE *);
144     fmt = va_arg(args, const char *);
145 #endif
146     n = vslprintf(buf, sizeof (buf), fmt, args);
147     va_end(args);
148     if (strptr == NULL) {
149 	bp = buf;
150 	ebp = buf + n;
151 	while (bp < ebp) {
152 	    if ((nlp = strchr(bp, '\n')) == NULL)
153 		nlp = ebp;
154 	    if (nlp > bp) {
155 		*nlp = '\0';
156 		syslog(LOG_DEBUG, "%s", bp);
157 	    }
158 	    bp = nlp + 1;
159 	}
160     } else {
161 	n = fwrite(buf, 1, n, strptr);
162     }
163     return (n);
164 }
165 
166 /*
167  * vslprintf - like slprintf, takes a va_list instead of a list of args.
168  */
169 #define OUTCHAR(c)	(buflen > 0? (--buflen, *buf++ = (c)): 0)
170 
171 int
172 vslprintf(buf, buflen, fmt, args)
173     char *buf;
174     int buflen;
175     const char *fmt;
176     va_list args;
177 {
178     int c, n, longs;
179     int width, prec, fillch;
180     int base, len, neg, quoted;
181 #ifdef SOL2
182     uint64_t val;
183     int64_t sval;
184 #else
185     unsigned long val;
186     long sval;
187 #endif
188     char *buf0, *mstr;
189     const char *f, *str;
190     unsigned char *p;
191     char num[32];	/* 2^64 is 20 chars decimal, 22 octal */
192     time_t t;
193     u_int32_t ip;
194     static const char hexchars[] = "0123456789abcdef";
195     struct buffer_info bufinfo;
196 
197     buf0 = buf;
198     --buflen;
199     while (buflen > 0) {
200 	for (f = fmt; *f != '%' && *f != 0; ++f)
201 	    ;
202 	if (f > fmt) {
203 	    len = f - fmt;
204 	    if (len > buflen)
205 		len = buflen;
206 	    (void) memcpy(buf, fmt, len);
207 	    buf += len;
208 	    buflen -= len;
209 	    fmt = f;
210 	}
211 	if (*fmt == 0)
212 	    break;
213 	c = *++fmt;
214 	width = 0;
215 	prec = -1;
216 	fillch = ' ';
217 	if (c == '0') {
218 	    fillch = '0';
219 	    c = *++fmt;
220 	}
221 	if (c == '*') {
222 	    width = va_arg(args, int);
223 	    c = *++fmt;
224 	} else {
225 	    while (isdigit(c)) {
226 		width = width * 10 + c - '0';
227 		c = *++fmt;
228 	    }
229 	}
230 	if (c == '.') {
231 	    c = *++fmt;
232 	    if (c == '*') {
233 		prec = va_arg(args, int);
234 		c = *++fmt;
235 	    } else {
236 		prec = 0;
237 		while (isdigit(c)) {
238 		    prec = prec * 10 + c - '0';
239 		    c = *++fmt;
240 		}
241 	    }
242 	}
243 	longs = 0;
244 	if (c == 'l') {
245 	    longs++;
246 	    c = *++fmt;
247 	    if (c == 'l') {
248 		longs++;
249 		c = *++fmt;
250 	    }
251 	}
252 	str = 0;
253 	base = 0;
254 	neg = 0;
255 	val = 0;
256 	++fmt;
257 	switch (c) {
258 	case 'u':
259 #ifdef SOL2
260 	    if (longs >= 2)
261 		val = va_arg(args, uint64_t);
262 	    else
263 #endif
264 	    if (longs > 0)
265 		val = va_arg(args, unsigned long);
266 	    else
267 		val = va_arg(args, unsigned int);
268 	    base = 10;
269 	    break;
270 	case 'd':
271 #ifdef SOL2
272 	    if (longs >= 2)
273 		sval = va_arg(args, int64_t);
274 	    else
275 #endif
276 	    if (longs > 0)
277 		sval = va_arg(args, long);
278 	    else
279 		sval = va_arg(args, int);
280 	    if (sval < 0) {
281 		neg = 1;
282 		val = -sval;
283 	    } else
284 		val = sval;
285 	    base = 10;
286 	    break;
287 	case 'o':
288 #ifdef SOL2
289 	    if (longs >= 2)
290 		val = va_arg(args, uint64_t);
291 	    else
292 #endif
293 	    if (longs > 0)
294 		val = va_arg(args, unsigned long);
295 	    else
296 		val = va_arg(args, unsigned int);
297 	    base = 8;
298 	    break;
299 	case 'x':
300 	case 'X':
301 #ifdef SOL2
302 	    if (longs >= 2)
303 		val = va_arg(args, uint64_t);
304 	    else
305 #endif
306 	    if (longs > 0)
307 		val = va_arg(args, unsigned long);
308 	    else
309 		val = va_arg(args, unsigned int);
310 	    base = 16;
311 	    break;
312 	case 'p':
313 	    val = (unsigned long) va_arg(args, void *);
314 	    base = 16;
315 	    neg = 2;
316 	    break;
317 	case 's':
318 	    str = va_arg(args, const char *);
319 	    break;
320 	case 'c':
321 	    num[0] = va_arg(args, int);
322 	    num[1] = 0;
323 	    str = num;
324 	    break;
325 	case 'm':
326 	    str = strerror(errno);
327 	    break;
328 	case 'I':
329 	    ip = va_arg(args, u_int32_t);
330 	    ip = ntohl(ip);
331 	    (void) slprintf(num, sizeof(num), "%d.%d.%d.%d", (ip >> 24) & 0xff,
332 		(ip >> 16) & 0xff, (ip >> 8) & 0xff, ip & 0xff);
333 	    str = num;
334 	    break;
335 	case 't':
336 	    (void) time(&t);
337 	    mstr = ctime(&t);
338 	    mstr += 4;		/* chop off the day name */
339 	    mstr[15] = 0;	/* chop off year and newline */
340 	    str = (const char *)mstr;
341 	    break;
342 	case 'v':		/* "visible" string */
343 	case 'q':		/* quoted string */
344 	    quoted = c == 'q';
345 	    p = va_arg(args, unsigned char *);
346 	    if (fillch == '0' && prec >= 0) {
347 		n = prec;
348 	    } else {
349 		n = strlen((char *)p);
350 		if (prec >= 0 && n > prec)
351 		    n = prec;
352 	    }
353 	    while (n > 0 && buflen > 0) {
354 		c = *p++;
355 		--n;
356 		if (!quoted && c >= 0x80) {
357 		    (void) OUTCHAR('M');
358 		    (void) OUTCHAR('-');
359 		    c -= 0x80;
360 		}
361 		if (quoted && (c == '"' || c == '\\'))
362 		    (void) OUTCHAR('\\');
363 		if (c < 0x20 || (0x7f <= c && c < 0xa0)) {
364 		    if (quoted) {
365 			(void) OUTCHAR('\\');
366 			switch (c) {
367 			case '\t':	(void) OUTCHAR('t');	break;
368 			case '\n':	(void) OUTCHAR('n');	break;
369 			case '\b':	(void) OUTCHAR('b');	break;
370 			case '\f':	(void) OUTCHAR('f');	break;
371 			default:
372 			    (void) OUTCHAR('x');
373 			    (void) OUTCHAR(hexchars[c >> 4]);
374 			    (void) OUTCHAR(hexchars[c & 0xf]);
375 			}
376 		    } else {
377 			if (c == '\t')
378 			    (void) OUTCHAR(c);
379 			else {
380 			    (void) OUTCHAR('^');
381 			    (void) OUTCHAR(c ^ 0x40);
382 			}
383 		    }
384 		} else
385 		    (void) OUTCHAR(c);
386 	    }
387 	    continue;
388 	case 'P':		/* print PPP packet */
389 	    bufinfo.ptr = buf;
390 	    bufinfo.len = buflen + 1;
391 	    p = va_arg(args, unsigned char *);
392 	    n = va_arg(args, int);
393 	    format_packet(p, n, vslp_printer, &bufinfo);
394 	    buf = bufinfo.ptr;
395 	    buflen = bufinfo.len - 1;
396 	    continue;
397 	case 'B':
398 	    p = va_arg(args, unsigned char *);
399 	    if ((n = prec) > width && width > 0)
400 		n = width;
401 	    /* For safety's sake */
402 	    if (n > 2000)
403 		    n = 2000;
404 	    while (--n >= 0) {
405 		c = *p++;
406 		if (fillch == ' ')
407 		    (void) OUTCHAR(' ');
408 		(void) OUTCHAR(hexchars[(c >> 4) & 0xf]);
409 		(void) OUTCHAR(hexchars[c & 0xf]);
410 	    }
411 	    if (prec > width && width > 0) {
412 		(void) OUTCHAR('.');
413 		(void) OUTCHAR('.');
414 		(void) OUTCHAR('.');
415 	    }
416 	    continue;
417 	default:
418 	    *buf++ = '%';
419 	    if (c != '%')
420 		--fmt;		/* so %z outputs %z etc. */
421 	    --buflen;
422 	    continue;
423 	}
424 	if (base != 0) {
425 	    mstr = num + sizeof(num);
426 	    *--mstr = 0;
427 	    while (mstr > num + neg) {
428 		*--mstr = hexchars[val % base];
429 		val = val / base;
430 		if (--prec <= 0 && val == 0)
431 		    break;
432 	    }
433 	    switch (neg) {
434 	    case 1:
435 		*--mstr = '-';
436 		break;
437 	    case 2:
438 		*--mstr = 'x';
439 		*--mstr = '0';
440 		break;
441 	    }
442 	    len = num + sizeof(num) - 1 - mstr;
443 	    str = (const char *)mstr;
444 	} else {
445 	    len = strlen(str);
446 	    if (prec >= 0 && len > prec)
447 		len = prec;
448 	}
449 	if (width > 0) {
450 	    if (width > buflen)
451 		width = buflen;
452 	    if ((n = width - len) > 0) {
453 		buflen -= n;
454 		for (; n > 0; --n)
455 		    *buf++ = fillch;
456 	    }
457 	}
458 	if (len > buflen)
459 	    len = buflen;
460 	(void) memcpy(buf, str, len);
461 	buf += len;
462 	buflen -= len;
463     }
464     *buf = 0;
465     return (buf - buf0);
466 }
467 
468 /*
469  * vslp_printer - used in processing a %P format
470  */
471 static void
472 vslp_printer __V((void *arg, const char *fmt, ...))
473 {
474     int n;
475     va_list pvar;
476     struct buffer_info *bi;
477 
478 #if defined(__STDC__)
479     va_start(pvar, fmt);
480 #else
481     void *arg;
482     const char *fmt;
483     va_start(pvar);
484     arg = va_arg(pvar, void *);
485     fmt = va_arg(pvar, const char *);
486 #endif
487 
488     bi = (struct buffer_info *) arg;
489     n = vslprintf(bi->ptr, bi->len, fmt, pvar);
490     va_end(pvar);
491 
492     bi->ptr += n;
493     bi->len -= n;
494 }
495 
496 /*
497  * log_packet - format a packet and log it.
498  */
499 
500 static char line[256];		/* line to be logged accumulated here */
501 static char *linep;
502 
503 void
504 log_packet(p, len, prefix, level)
505     u_char *p;
506     int len;
507     const char *prefix;
508     int level;
509 {
510     (void) strlcpy(line, prefix, sizeof(line));
511     linep = line + strlen(line);
512     format_packet(p, len, pr_log, (void *)level);
513     if (linep != line)
514 	syslog(level, "%s", line);
515 }
516 
517 /*
518  * format_packet - make a readable representation of a packet,
519  * calling `printer(arg, format, ...)' to output it.
520  */
521 static void
522 format_packet(p, len, printer, arg)
523     u_char *p;
524     int len;
525     void (*printer) __P((void *, const char *, ...));
526     void *arg;
527 {
528     int i, n;
529     u_short proto;
530     struct protent *protp;
531 
532     if (len >= PPP_HDRLEN && p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) {
533 	p += 2;
534 	GETSHORT(proto, p);
535 	len -= PPP_HDRLEN;
536 	for (i = 0; (protp = protocols[i]) != NULL; ++i)
537 	    if (proto == protp->protocol)
538 		break;
539 	if (protp != NULL) {
540 	    printer(arg, "[%s", protp->name);
541 	    n = (*protp->printpkt)(p, len, printer, arg);
542 	    printer(arg, "]");
543 	    p += n;
544 	    len -= n;
545 	} else {
546 	    for (i = 0; (protp = protocols[i]) != NULL; ++i)
547 		if (proto == (protp->protocol & ~0x8000))
548 		    break;
549 	    if (protp != NULL && protp->data_name != NULL) {
550 		printer(arg, "[%s data] %8.*B", protp->data_name, len, p);
551 		len = 0;
552 	    } else
553 		printer(arg, "[proto=0x%x]", proto);
554 	}
555     }
556 
557     printer(arg, "%32.*B", len, p);
558 }
559 
560 static void
561 pr_log __V((void *arg, const char *fmt, ...))
562 {
563     int n;
564     va_list pvar;
565     char buf[256];
566 
567 #if defined(__STDC__)
568     va_start(pvar, fmt);
569 #else
570     void *arg;
571     const char *fmt;
572     va_start(pvar);
573     arg = va_arg(pvar, void *);
574     fmt = va_arg(pvar, const char *);
575 #endif
576 
577     n = vslprintf(buf, sizeof(buf), fmt, pvar);
578     va_end(pvar);
579 
580     if (linep + n + 1 > line + sizeof(line)) {
581 	syslog((int)arg, "%s", line);
582 	linep = line;
583     }
584     (void) strlcpy(linep, buf, line + sizeof(line) - linep);
585     linep += n;
586 }
587 
588 /*
589  * print_string - print a readable representation of a string using
590  * printer.
591  */
592 void
593 print_string(p, len, printer, arg)
594     char *p;
595     int len;
596     void (*printer) __P((void *, const char *, ...));
597     void *arg;
598 {
599     int c;
600 
601     printer(arg, "\"");
602     for (; len > 0; --len) {
603 	c = *p++;
604 	if (isprint(c)) {
605 	    if (c == '\\' || c == '"')
606 		printer(arg, "\\");
607 	    printer(arg, "%c", c);
608 	} else {
609 	    switch (c) {
610 	    case '\n':
611 		printer(arg, "\\n");
612 		break;
613 	    case '\r':
614 		printer(arg, "\\r");
615 		break;
616 	    case '\t':
617 		printer(arg, "\\t");
618 		break;
619 	    default:
620 		printer(arg, "\\%.3o", c);
621 	    }
622 	}
623     }
624     printer(arg, "\"");
625 }
626 
627 /*
628  * logit - does the hard work for fatal et al.
629  */
630 static void
631 logit(level, fmt, args)
632     int level;
633     const char *fmt;
634     va_list args;
635 {
636     int n;
637     char buf[1024];
638 
639     n = vslprintf(buf, sizeof(buf), fmt, args);
640     syslog(level, "%s", buf);
641     if (log_to_fd >= 0 && (level != LOG_DEBUG || debug) &&
642 	(!early_log || log_to_specific_fd)) {
643 	if (buf[n-1] != '\n')
644 	    buf[n++] = '\n';
645 	if (write(log_to_fd, buf, n) != n)
646 	    log_to_fd = -1;
647     }
648 }
649 
650 /*
651  * fatal - log an error message and die horribly.
652  */
653 void
654 fatal __V((const char *fmt, ...))
655 {
656     va_list pvar;
657 
658 #if defined(__STDC__)
659     va_start(pvar, fmt);
660 #else
661     const char *fmt;
662     va_start(pvar);
663     fmt = va_arg(pvar, const char *);
664 #endif
665 
666     logit(LOG_ERR, fmt, pvar);
667     va_end(pvar);
668 
669     die(1);			/* as promised */
670 }
671 
672 /*
673  * error - log an error message.
674  */
675 void
676 error __V((const char *fmt, ...))
677 {
678     va_list pvar;
679 
680 #if defined(__STDC__)
681     va_start(pvar, fmt);
682 #else
683     const char *fmt;
684     va_start(pvar);
685     fmt = va_arg(pvar, const char *);
686 #endif
687 
688     logit(LOG_ERR, fmt, pvar);
689     va_end(pvar);
690 }
691 
692 /*
693  * warn - log a warning message.
694  */
695 void
696 warn __V((const char *fmt, ...))
697 {
698     va_list pvar;
699 
700 #if defined(__STDC__)
701     va_start(pvar, fmt);
702 #else
703     const char *fmt;
704     va_start(pvar);
705     fmt = va_arg(pvar, const char *);
706 #endif
707 
708     logit(LOG_WARNING, fmt, pvar);
709     va_end(pvar);
710 }
711 
712 /*
713  * notice - log a notice-level message.
714  */
715 void
716 notice __V((const char *fmt, ...))
717 {
718     va_list pvar;
719 
720 #if defined(__STDC__)
721     va_start(pvar, fmt);
722 #else
723     const char *fmt;
724     va_start(pvar);
725     fmt = va_arg(pvar, const char *);
726 #endif
727 
728     logit(LOG_NOTICE, fmt, pvar);
729     va_end(pvar);
730 }
731 
732 /*
733  * info - log an informational message.
734  */
735 void
736 info __V((const char *fmt, ...))
737 {
738     va_list pvar;
739 
740 #if defined(__STDC__)
741     va_start(pvar, fmt);
742 #else
743     const char *fmt;
744     va_start(pvar);
745     fmt = va_arg(pvar, const char *);
746 #endif
747 
748     logit(LOG_INFO, fmt, pvar);
749     va_end(pvar);
750 }
751 
752 /*
753  * dbglog - log a debug message.
754  */
755 void
756 dbglog __V((const char *fmt, ...))
757 {
758     va_list pvar;
759 
760 #if defined(__STDC__)
761     va_start(pvar, fmt);
762 #else
763     const char *fmt;
764     va_start(pvar);
765     fmt = va_arg(pvar, const char *);
766 #endif
767 
768     logit(LOG_DEBUG, fmt, pvar);
769     va_end(pvar);
770 }
771 
772 /*
773  * Code names for regular PPP messages.  Used by LCP and most NCPs,
774  * not used by authentication protocols.
775  */
776 const char *
777 code_name(int code, int shortflag)
778 {
779     static const char *codelist[] = {
780 	"Vendor-Extension", "Configure-Request", "Configure-Ack",
781 	"Configure-Nak", "Configure-Reject", "Terminate-Request",
782 	"Terminate-Ack", "Code-Reject", "Protocol-Reject",
783 	"Echo-Request", "Echo-Reply", "Discard-Request",
784 	"Identification", "Time-Remaining",
785 	"Reset-Request", "Reset-Ack"
786     };
787     static const char *shortcode[] = {
788 	"VendExt", "ConfReq", "ConfAck",
789 	"ConfNak", "ConfRej", "TermReq",
790 	"TermAck", "CodeRej", "ProtRej",
791 	"EchoReq", "EchoRep", "DiscReq",
792 	"Ident", "TimeRem",
793 	"ResetReq", "ResetAck"
794     };
795     static char msgbuf[64];
796 
797     if (code < 0 || code >= sizeof (codelist) / sizeof (*codelist)) {
798 	if (shortflag)
799 	    (void) slprintf(msgbuf, sizeof (msgbuf), "Code#%d", code);
800 	else
801 	    (void) slprintf(msgbuf, sizeof (msgbuf), "unknown code %d", code);
802 	return ((const char *)msgbuf);
803     }
804     return (shortflag ? shortcode[code] : codelist[code]);
805 }
806 
807 /* Procedures for locking the serial device using a lock file. */
808 #ifndef LOCK_DIR
809 #ifdef _linux_
810 #define LOCK_DIR	"/var/lock"
811 #else
812 #ifdef SVR4
813 #define LOCK_DIR	"/var/spool/locks"
814 #else
815 #define LOCK_DIR	"/var/spool/lock"
816 #endif
817 #endif
818 #endif /* LOCK_DIR */
819 
820 static char lock_file[MAXPATHLEN];
821 
822 /*
823  * lock - create a lock file for the named device
824  */
825 int
826 lock(dev)
827     char *dev;
828 {
829 #ifdef LOCKLIB
830     int result;
831 
832     result = mklock (dev, (void *) 0);
833     if (result == 0) {
834 	(void) strlcpy(lock_file, sizeof(lock_file), dev);
835 	return (0);
836     }
837 
838     if (result > 0)
839         notice("Device %s is locked by pid %d", dev, result);
840     else
841 	error("Can't create lock file %s", lock_file);
842     return (-1);
843 
844 #else /* LOCKLIB */
845 
846     char lock_buffer[12];
847     int fd, pid, n;
848 
849 #ifdef SVR4
850     struct stat sbuf;
851 
852     if (stat(dev, &sbuf) < 0) {
853 	error("Can't get device number for %s: %m", dev);
854 	return (-1);
855     }
856     if ((sbuf.st_mode & S_IFMT) != S_IFCHR) {
857 	error("Can't lock %s: not a character device", dev);
858 	return (-1);
859     }
860     (void) slprintf(lock_file, sizeof(lock_file), "%s/LK.%03d.%03d.%03d",
861 	     LOCK_DIR, major(sbuf.st_dev),
862 	     major(sbuf.st_rdev), minor(sbuf.st_rdev));
863 #else
864     char *p;
865 
866     if ((p = strrchr(dev, '/')) != NULL)
867 	dev = p + 1;
868     (void) slprintf(lock_file, sizeof(lock_file), "%s/LCK..%s", LOCK_DIR, dev);
869 #endif
870 
871     while ((fd = open(lock_file, O_EXCL | O_CREAT | O_RDWR, 0644)) < 0) {
872 	if (errno != EEXIST) {
873 	    error("Can't create lock file %s: %m", lock_file);
874 	    break;
875 	}
876 
877 	/* Read the lock file to find out who has the device locked. */
878 	fd = open(lock_file, O_RDONLY, 0);
879 	if (fd < 0) {
880 	    if (errno == ENOENT) /* This is just a timing problem. */
881 		continue;
882 	    error("Can't open existing lock file %s: %m", lock_file);
883 	    break;
884 	}
885 #ifndef LOCK_BINARY
886 	n = read(fd, lock_buffer, 11);
887 #else
888 	n = read(fd, &pid, sizeof(pid));
889 #endif /* LOCK_BINARY */
890 	(void) close(fd);
891 	fd = -1;
892 	if (n <= 0) {
893 	    error("Can't read pid from lock file %s", lock_file);
894 	    break;
895 	}
896 
897 	/* See if the process still exists. */
898 #ifndef LOCK_BINARY
899 	lock_buffer[n] = 0;
900 	pid = atoi(lock_buffer);
901 #endif /* LOCK_BINARY */
902 	if (pid == getpid())
903 	    return (1);		/* somebody else locked it for us */
904 	if (pid == 0
905 	    || (kill(pid, 0) == -1 && errno == ESRCH)) {
906 	    if (unlink (lock_file) == 0) {
907 		notice("Removed stale lock on %s (pid %d)", dev, pid);
908 		continue;
909 	    }
910 	    warn("Couldn't remove stale lock on %s", dev);
911 	} else
912 	    notice("Device %s is locked by pid %d", dev, pid);
913 	break;
914     }
915 
916     if (fd < 0) {
917 	lock_file[0] = 0;
918 	return (-1);
919     }
920 
921     pid = getpid();
922 #ifndef LOCK_BINARY
923     (void) slprintf(lock_buffer, sizeof(lock_buffer), "%10d\n", pid);
924     (void) write (fd, lock_buffer, 11);
925 #else
926     (void) write(fd, &pid, sizeof (pid));
927 #endif
928     (void) close(fd);
929     return (0);
930 
931 #endif
932 }
933 
934 /*
935  * relock - called to update our lockfile when we are about to detach,
936  * thus changing our pid (we fork, the child carries on, and the parent dies).
937  * Note that this is called by the parent, with pid equal to the pid
938  * of the child.  This avoids a potential race which would exist if
939  * we had the child rewrite the lockfile (the parent might die first,
940  * and another process could think the lock was stale if it checked
941  * between when the parent died and the child rewrote the lockfile).
942  */
943 int
944 relock(pid)
945     int pid;
946 {
947 #ifdef LOCKLIB
948     /* XXX is there a way to do this? */
949     return (-1);
950 #else /* LOCKLIB */
951 
952     int fd;
953     char lock_buffer[12];
954 
955     if (lock_file[0] == 0)
956 	return (-1);
957     fd = open(lock_file, O_WRONLY, 0);
958     if (fd < 0) {
959 	error("Couldn't reopen lock file %s: %m", lock_file);
960 	lock_file[0] = 0;
961 	return (-1);
962     }
963 
964 #ifndef LOCK_BINARY
965     (void) slprintf(lock_buffer, sizeof(lock_buffer), "%10d\n", pid);
966     (void) write (fd, lock_buffer, 11);
967 #else
968     (void) write(fd, &pid, sizeof(pid));
969 #endif /* LOCK_BINARY */
970     (void) close(fd);
971     return (0);
972 
973 #endif /* LOCKLIB */
974 }
975 
976 /*
977  * unlock - remove our lockfile
978  */
979 void
980 unlock()
981 {
982     if (lock_file[0]) {
983 #ifdef LOCKLIB
984 	(void) rmlock(lock_file, (void *) 0);
985 #else
986 	(void) unlink(lock_file);
987 #endif
988 	lock_file[0] = 0;
989     }
990 }
991 
992 const char *
993 signal_name(int signum)
994 {
995 #if defined(SOL2) || defined(__linux__) || defined(_linux_)
996     const char *cp;
997 
998     if ((cp = strsignal(signum)) != NULL)
999 	return (cp);
1000 #else
1001     extern char *sys_siglist[];
1002     extern int sys_nsig;
1003 
1004     if (signum >= 0 && signum < sys_nsig && sys_siglist[signum] != NULL)
1005 	return (sys_siglist[signum]);
1006 #endif
1007     return ("??");
1008 }
1009