1 /*
2 * utils.c - various utility functions used in pppd.
3 *
4 * Copyright (c) 1999-2002 Paul Mackerras. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 *
13 * 2. The name(s) of the authors of this software must not be used to
14 * endorse or promote products derived from this software without
15 * prior written permission.
16 *
17 * 3. Redistributions of any form whatsoever must retain the following
18 * acknowledgment:
19 * "This product includes software developed by Paul Mackerras
20 * <paulus@samba.org>".
21 *
22 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
23 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
24 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
25 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
26 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
27 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
28 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
29 */
30
31 #define RCSID "$Id: utils.c,v 1.25 2008/06/03 12:06:37 paulus Exp $"
32
33 #include <stdio.h>
34 #include <ctype.h>
35 #include <stdlib.h>
36 #include <string.h>
37 #include <unistd.h>
38 #include <signal.h>
39 #include <errno.h>
40 #include <fcntl.h>
41 #include <syslog.h>
42 #include <netdb.h>
43 #include <time.h>
44 #include <utmp.h>
45 #include <pwd.h>
46 #include <sys/param.h>
47 #include <sys/types.h>
48 #include <sys/wait.h>
49 #include <sys/time.h>
50 #include <sys/resource.h>
51 #include <sys/stat.h>
52 #include <sys/socket.h>
53 #include <netinet/in.h>
54 #ifdef SVR4
55 #include <sys/mkdev.h>
56 #endif
57
58 #include "pppd.h"
59 #include "fsm.h"
60 #include "lcp.h"
61
62 static const char rcsid[] = RCSID;
63
64 #if defined(SUNOS4)
65 extern char *strerror();
66 #endif
67
68 static void logit __P((int, char *, va_list));
69 static void log_write __P((int, char *));
70 static void vslp_printer __P((void *, char *, ...));
71 static void format_packet __P((u_char *, int, printer_func, void *));
72
73 struct buffer_info {
74 char *ptr;
75 int len;
76 };
77
78 #if !defined(__ANDROID__)
79
80 /*
81 * strlcpy - like strcpy/strncpy, doesn't overflow destination buffer,
82 * always leaves destination null-terminated (for len > 0).
83 */
84 size_t
strlcpy(dest,src,len)85 strlcpy(dest, src, len)
86 char *dest;
87 const char *src;
88 size_t len;
89 {
90 size_t ret = strlen(src);
91
92 if (len != 0) {
93 if (ret < len)
94 strcpy(dest, src);
95 else {
96 strncpy(dest, src, len - 1);
97 dest[len-1] = 0;
98 }
99 }
100 return ret;
101 }
102
103 /*
104 * strlcat - like strcat/strncat, doesn't overflow destination buffer,
105 * always leaves destination null-terminated (for len > 0).
106 */
107 size_t
strlcat(dest,src,len)108 strlcat(dest, src, len)
109 char *dest;
110 const char *src;
111 size_t len;
112 {
113 size_t dlen = strlen(dest);
114
115 return dlen + strlcpy(dest + dlen, src, (len > dlen? len - dlen: 0));
116 }
117 #endif
118
119
120 /*
121 * slprintf - format a message into a buffer. Like sprintf except we
122 * also specify the length of the output buffer, and we handle
123 * %m (error message), %v (visible string),
124 * %q (quoted string), %t (current time) and %I (IP address) formats.
125 * Doesn't do floating-point formats.
126 * Returns the number of chars put into buf.
127 */
128 int
slprintf(char * buf,int buflen,char * fmt,...)129 slprintf __V((char *buf, int buflen, char *fmt, ...))
130 {
131 va_list args;
132 int n;
133
134 #if defined(__STDC__)
135 va_start(args, fmt);
136 #else
137 char *buf;
138 int buflen;
139 char *fmt;
140 va_start(args);
141 buf = va_arg(args, char *);
142 buflen = va_arg(args, int);
143 fmt = va_arg(args, char *);
144 #endif
145 n = vslprintf(buf, buflen, fmt, args);
146 va_end(args);
147 return n;
148 }
149
150 /*
151 * vslprintf - like slprintf, takes a va_list instead of a list of args.
152 */
153 #define OUTCHAR(c) (buflen > 0? (--buflen, *buf++ = (c)): 0)
154
155 int
vslprintf(buf,buflen,fmt,args)156 vslprintf(buf, buflen, fmt, args)
157 char *buf;
158 int buflen;
159 char *fmt;
160 va_list args;
161 {
162 int c, i, n;
163 int width, prec, fillch;
164 int base, len, neg, quoted;
165 unsigned long val = 0;
166 char *str, *f, *buf0;
167 unsigned char *p;
168 char num[32];
169 time_t t;
170 u_int32_t ip;
171 static char hexchars[] = "0123456789abcdef";
172 struct buffer_info bufinfo;
173
174 buf0 = buf;
175 --buflen;
176 while (buflen > 0) {
177 for (f = fmt; *f != '%' && *f != 0; ++f)
178 ;
179 if (f > fmt) {
180 len = f - fmt;
181 if (len > buflen)
182 len = buflen;
183 memcpy(buf, fmt, len);
184 buf += len;
185 buflen -= len;
186 fmt = f;
187 }
188 if (*fmt == 0)
189 break;
190 c = *++fmt;
191 width = 0;
192 prec = -1;
193 fillch = ' ';
194 if (c == '0') {
195 fillch = '0';
196 c = *++fmt;
197 }
198 if (c == '*') {
199 width = va_arg(args, int);
200 c = *++fmt;
201 } else {
202 while (isdigit(c)) {
203 width = width * 10 + c - '0';
204 c = *++fmt;
205 }
206 }
207 if (c == '.') {
208 c = *++fmt;
209 if (c == '*') {
210 prec = va_arg(args, int);
211 c = *++fmt;
212 } else {
213 prec = 0;
214 while (isdigit(c)) {
215 prec = prec * 10 + c - '0';
216 c = *++fmt;
217 }
218 }
219 }
220 str = 0;
221 base = 0;
222 neg = 0;
223 ++fmt;
224 switch (c) {
225 case 'l':
226 c = *fmt++;
227 switch (c) {
228 case 'd':
229 val = va_arg(args, long);
230 #if defined(__ANDROID__)
231 if ((long)val < 0) {
232 neg = 1;
233 val = (unsigned long)(-(long)val);
234 }
235 #else
236 if (val < 0) {
237 neg = 1;
238 val = -val;
239 }
240 #endif
241 base = 10;
242 break;
243 case 'u':
244 val = va_arg(args, unsigned long);
245 base = 10;
246 break;
247 default:
248 OUTCHAR('%');
249 OUTCHAR('l');
250 --fmt; /* so %lz outputs %lz etc. */
251 continue;
252 }
253 break;
254 case 'd':
255 i = va_arg(args, int);
256 if (i < 0) {
257 neg = 1;
258 val = -i;
259 } else
260 val = i;
261 base = 10;
262 break;
263 case 'u':
264 val = va_arg(args, unsigned int);
265 base = 10;
266 break;
267 case 'o':
268 val = va_arg(args, unsigned int);
269 base = 8;
270 break;
271 case 'x':
272 case 'X':
273 val = va_arg(args, unsigned int);
274 base = 16;
275 break;
276 case 'p':
277 val = (unsigned long) va_arg(args, void *);
278 base = 16;
279 neg = 2;
280 break;
281 case 's':
282 str = va_arg(args, char *);
283 break;
284 case 'c':
285 num[0] = va_arg(args, int);
286 num[1] = 0;
287 str = num;
288 break;
289 case 'm':
290 str = strerror(errno);
291 break;
292 case 'I':
293 ip = va_arg(args, u_int32_t);
294 ip = ntohl(ip);
295 slprintf(num, sizeof(num), "%d.%d.%d.%d", (ip >> 24) & 0xff,
296 (ip >> 16) & 0xff, (ip >> 8) & 0xff, ip & 0xff);
297 str = num;
298 break;
299 case 't':
300 time(&t);
301 str = ctime(&t);
302 str += 4; /* chop off the day name */
303 str[15] = 0; /* chop off year and newline */
304 break;
305 case 'v': /* "visible" string */
306 case 'q': /* quoted string */
307 quoted = c == 'q';
308 p = va_arg(args, unsigned char *);
309 if (p == NULL)
310 p = (unsigned char *)"<NULL>";
311 if (fillch == '0' && prec >= 0) {
312 n = prec;
313 } else {
314 n = strlen((char *)p);
315 if (prec >= 0 && n > prec)
316 n = prec;
317 }
318 while (n > 0 && buflen > 0) {
319 c = *p++;
320 --n;
321 if (!quoted && c >= 0x80) {
322 OUTCHAR('M');
323 OUTCHAR('-');
324 c -= 0x80;
325 }
326 if (quoted && (c == '"' || c == '\\'))
327 OUTCHAR('\\');
328 if (c < 0x20 || (0x7f <= c && c < 0xa0)) {
329 if (quoted) {
330 OUTCHAR('\\');
331 switch (c) {
332 case '\t': OUTCHAR('t'); break;
333 case '\n': OUTCHAR('n'); break;
334 case '\b': OUTCHAR('b'); break;
335 case '\f': OUTCHAR('f'); break;
336 default:
337 OUTCHAR('x');
338 OUTCHAR(hexchars[c >> 4]);
339 OUTCHAR(hexchars[c & 0xf]);
340 }
341 } else {
342 if (c == '\t')
343 OUTCHAR(c);
344 else {
345 OUTCHAR('^');
346 OUTCHAR(c ^ 0x40);
347 }
348 }
349 } else
350 OUTCHAR(c);
351 }
352 continue;
353 case 'P': /* print PPP packet */
354 bufinfo.ptr = buf;
355 bufinfo.len = buflen + 1;
356 p = va_arg(args, unsigned char *);
357 n = va_arg(args, int);
358 format_packet(p, n, vslp_printer, &bufinfo);
359 buf = bufinfo.ptr;
360 buflen = bufinfo.len - 1;
361 continue;
362 case 'B':
363 p = va_arg(args, unsigned char *);
364 for (n = prec; n > 0; --n) {
365 c = *p++;
366 if (fillch == ' ')
367 OUTCHAR(' ');
368 OUTCHAR(hexchars[(c >> 4) & 0xf]);
369 OUTCHAR(hexchars[c & 0xf]);
370 }
371 continue;
372 default:
373 *buf++ = '%';
374 if (c != '%')
375 --fmt; /* so %z outputs %z etc. */
376 --buflen;
377 continue;
378 }
379 if (base != 0) {
380 str = num + sizeof(num);
381 *--str = 0;
382 while (str > num + neg) {
383 *--str = hexchars[val % base];
384 val = val / base;
385 if (--prec <= 0 && val == 0)
386 break;
387 }
388 switch (neg) {
389 case 1:
390 *--str = '-';
391 break;
392 case 2:
393 *--str = 'x';
394 *--str = '0';
395 break;
396 }
397 len = num + sizeof(num) - 1 - str;
398 } else {
399 len = strlen(str);
400 if (prec >= 0 && len > prec)
401 len = prec;
402 }
403 if (width > 0) {
404 if (width > buflen)
405 width = buflen;
406 if ((n = width - len) > 0) {
407 buflen -= n;
408 for (; n > 0; --n)
409 *buf++ = fillch;
410 }
411 }
412 if (len > buflen)
413 len = buflen;
414 memcpy(buf, str, len);
415 buf += len;
416 buflen -= len;
417 }
418 *buf = 0;
419 return buf - buf0;
420 }
421
422 /*
423 * vslp_printer - used in processing a %P format
424 */
425 static void
vslp_printer(void * arg,char * fmt,...)426 vslp_printer __V((void *arg, char *fmt, ...))
427 {
428 int n;
429 va_list pvar;
430 struct buffer_info *bi;
431
432 #if defined(__STDC__)
433 va_start(pvar, fmt);
434 #else
435 void *arg;
436 char *fmt;
437 va_start(pvar);
438 arg = va_arg(pvar, void *);
439 fmt = va_arg(pvar, char *);
440 #endif
441
442 bi = (struct buffer_info *) arg;
443 n = vslprintf(bi->ptr, bi->len, fmt, pvar);
444 va_end(pvar);
445
446 bi->ptr += n;
447 bi->len -= n;
448 }
449
450 #ifdef unused
451 /*
452 * log_packet - format a packet and log it.
453 */
454
455 void
log_packet(p,len,prefix,level)456 log_packet(p, len, prefix, level)
457 u_char *p;
458 int len;
459 char *prefix;
460 int level;
461 {
462 init_pr_log(prefix, level);
463 format_packet(p, len, pr_log, &level);
464 end_pr_log();
465 }
466 #endif /* unused */
467
468 /*
469 * format_packet - make a readable representation of a packet,
470 * calling `printer(arg, format, ...)' to output it.
471 */
472 static void
format_packet(p,len,printer,arg)473 format_packet(p, len, printer, arg)
474 u_char *p;
475 int len;
476 printer_func printer;
477 void *arg;
478 {
479 int i, n;
480 u_short proto;
481 struct protent *protp;
482
483 if (len >= PPP_HDRLEN && p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) {
484 p += 2;
485 GETSHORT(proto, p);
486 len -= PPP_HDRLEN;
487 for (i = 0; (protp = protocols[i]) != NULL; ++i)
488 if (proto == protp->protocol)
489 break;
490 if (protp != NULL) {
491 printer(arg, "[%s", protp->name);
492 n = (*protp->printpkt)(p, len, printer, arg);
493 printer(arg, "]");
494 p += n;
495 len -= n;
496 } else {
497 for (i = 0; (protp = protocols[i]) != NULL; ++i)
498 if (proto == (protp->protocol & ~0x8000))
499 break;
500 if (protp != 0 && protp->data_name != 0) {
501 printer(arg, "[%s data]", protp->data_name);
502 if (len > 8)
503 printer(arg, "%.8B ...", p);
504 else
505 printer(arg, "%.*B", len, p);
506 len = 0;
507 } else
508 printer(arg, "[proto=0x%x]", proto);
509 }
510 }
511
512 if (len > 32)
513 printer(arg, "%.32B ...", p);
514 else
515 printer(arg, "%.*B", len, p);
516 }
517
518 /*
519 * init_pr_log, end_pr_log - initialize and finish use of pr_log.
520 */
521
522 static char line[256]; /* line to be logged accumulated here */
523 static char *linep; /* current pointer within line */
524 static int llevel; /* level for logging */
525
526 void
init_pr_log(prefix,level)527 init_pr_log(prefix, level)
528 const char *prefix;
529 int level;
530 {
531 linep = line;
532 if (prefix != NULL) {
533 strlcpy(line, prefix, sizeof(line));
534 linep = line + strlen(line);
535 }
536 llevel = level;
537 }
538
539 void
end_pr_log()540 end_pr_log()
541 {
542 if (linep != line) {
543 *linep = 0;
544 log_write(llevel, line);
545 }
546 }
547
548 /*
549 * pr_log - printer routine for outputting to syslog
550 */
551 void
pr_log(void * arg,char * fmt,...)552 pr_log __V((void *arg, char *fmt, ...))
553 {
554 int l, n;
555 va_list pvar;
556 char *p, *eol;
557 char buf[256];
558
559 #if defined(__STDC__)
560 va_start(pvar, fmt);
561 #else
562 void *arg;
563 char *fmt;
564 va_start(pvar);
565 arg = va_arg(pvar, void *);
566 fmt = va_arg(pvar, char *);
567 #endif
568
569 n = vslprintf(buf, sizeof(buf), fmt, pvar);
570 va_end(pvar);
571
572 p = buf;
573 eol = strchr(buf, '\n');
574 if (linep != line) {
575 l = (eol == NULL)? n: eol - buf;
576 if (linep + l < line + sizeof(line)) {
577 if (l > 0) {
578 memcpy(linep, buf, l);
579 linep += l;
580 }
581 if (eol == NULL)
582 return;
583 p = eol + 1;
584 eol = strchr(p, '\n');
585 }
586 *linep = 0;
587 log_write(llevel, line);
588 linep = line;
589 }
590
591 while (eol != NULL) {
592 *eol = 0;
593 log_write(llevel, p);
594 p = eol + 1;
595 eol = strchr(p, '\n');
596 }
597
598 /* assumes sizeof(buf) <= sizeof(line) */
599 l = buf + n - p;
600 if (l > 0) {
601 memcpy(line, p, n);
602 linep = line + l;
603 }
604 }
605
606 /*
607 * print_string - print a readable representation of a string using
608 * printer.
609 */
610 void
print_string(p,len,printer,arg)611 print_string(p, len, printer, arg)
612 char *p;
613 int len;
614 printer_func printer;
615 void *arg;
616 {
617 int c;
618
619 printer(arg, "\"");
620 for (; len > 0; --len) {
621 c = *p++;
622 if (' ' <= c && c <= '~') {
623 if (c == '\\' || c == '"')
624 printer(arg, "\\");
625 printer(arg, "%c", c);
626 } else {
627 switch (c) {
628 case '\n':
629 printer(arg, "\\n");
630 break;
631 case '\r':
632 printer(arg, "\\r");
633 break;
634 case '\t':
635 printer(arg, "\\t");
636 break;
637 default:
638 printer(arg, "\\%.3o", c);
639 }
640 }
641 }
642 printer(arg, "\"");
643 }
644
645 /*
646 * logit - does the hard work for fatal et al.
647 */
648 static void
logit(level,fmt,args)649 logit(level, fmt, args)
650 int level;
651 char *fmt;
652 va_list args;
653 {
654 char buf[1024];
655
656 vslprintf(buf, sizeof(buf), fmt, args);
657 log_write(level, buf);
658 }
659
660 static void
log_write(level,buf)661 log_write(level, buf)
662 int level;
663 char *buf;
664 {
665 syslog(level, "%s", buf);
666 if (log_to_fd >= 0 && (level != LOG_DEBUG || debug)) {
667 int n = strlen(buf);
668
669 if (n > 0 && buf[n-1] == '\n')
670 --n;
671 if (write(log_to_fd, buf, n) != n
672 || write(log_to_fd, "\n", 1) != 1)
673 log_to_fd = -1;
674 }
675 }
676
677 /*
678 * fatal - log an error message and die horribly.
679 */
680 void
fatal(char * fmt,...)681 fatal __V((char *fmt, ...))
682 {
683 va_list pvar;
684
685 #if defined(__STDC__)
686 va_start(pvar, fmt);
687 #else
688 char *fmt;
689 va_start(pvar);
690 fmt = va_arg(pvar, char *);
691 #endif
692
693 logit(LOG_ERR, fmt, pvar);
694 va_end(pvar);
695
696 die(1); /* as promised */
697 }
698
699 /*
700 * error - log an error message.
701 */
702 void
error(char * fmt,...)703 error __V((char *fmt, ...))
704 {
705 va_list pvar;
706
707 #if defined(__STDC__)
708 va_start(pvar, fmt);
709 #else
710 char *fmt;
711 va_start(pvar);
712 fmt = va_arg(pvar, char *);
713 #endif
714
715 logit(LOG_ERR, fmt, pvar);
716 va_end(pvar);
717 ++error_count;
718 }
719
720 /*
721 * warn - log a warning message.
722 */
723 void
warn(char * fmt,...)724 warn __V((char *fmt, ...))
725 {
726 va_list pvar;
727
728 #if defined(__STDC__)
729 va_start(pvar, fmt);
730 #else
731 char *fmt;
732 va_start(pvar);
733 fmt = va_arg(pvar, char *);
734 #endif
735
736 logit(LOG_WARNING, fmt, pvar);
737 va_end(pvar);
738 }
739
740 /*
741 * notice - log a notice-level message.
742 */
743 void
notice(char * fmt,...)744 notice __V((char *fmt, ...))
745 {
746 va_list pvar;
747
748 #if defined(__STDC__)
749 va_start(pvar, fmt);
750 #else
751 char *fmt;
752 va_start(pvar);
753 fmt = va_arg(pvar, char *);
754 #endif
755
756 logit(LOG_NOTICE, fmt, pvar);
757 va_end(pvar);
758 }
759
760 /*
761 * info - log an informational message.
762 */
763 void
info(char * fmt,...)764 info __V((char *fmt, ...))
765 {
766 va_list pvar;
767
768 #if defined(__STDC__)
769 va_start(pvar, fmt);
770 #else
771 char *fmt;
772 va_start(pvar);
773 fmt = va_arg(pvar, char *);
774 #endif
775
776 logit(LOG_INFO, fmt, pvar);
777 va_end(pvar);
778 }
779
780 /*
781 * dbglog - log a debug message.
782 */
783 void
dbglog(char * fmt,...)784 dbglog __V((char *fmt, ...))
785 {
786 va_list pvar;
787
788 #if defined(__STDC__)
789 va_start(pvar, fmt);
790 #else
791 char *fmt;
792 va_start(pvar);
793 fmt = va_arg(pvar, char *);
794 #endif
795
796 logit(LOG_DEBUG, fmt, pvar);
797 va_end(pvar);
798 }
799
800 /*
801 * dump_packet - print out a packet in readable form if it is interesting.
802 * Assumes len >= PPP_HDRLEN.
803 */
804 void
dump_packet(const char * tag,unsigned char * p,int len)805 dump_packet(const char *tag, unsigned char *p, int len)
806 {
807 int proto;
808
809 if (!debug)
810 return;
811
812 /*
813 * don't print LCP echo request/reply packets if debug <= 1
814 * and the link is up.
815 */
816 proto = (p[2] << 8) + p[3];
817 if (debug <= 1 && unsuccess == 0 && proto == PPP_LCP
818 && len >= PPP_HDRLEN + HEADERLEN) {
819 unsigned char *lcp = p + PPP_HDRLEN;
820 int l = (lcp[2] << 8) + lcp[3];
821
822 if ((lcp[0] == ECHOREQ || lcp[0] == ECHOREP)
823 && l >= HEADERLEN && l <= len - PPP_HDRLEN)
824 return;
825 }
826
827 dbglog("%s %P", tag, p, len);
828 }
829
830 /*
831 * complete_read - read a full `count' bytes from fd,
832 * unless end-of-file or an error other than EINTR is encountered.
833 */
834 ssize_t
complete_read(int fd,void * buf,size_t count)835 complete_read(int fd, void *buf, size_t count)
836 {
837 size_t done;
838 ssize_t nb;
839 char *ptr = buf;
840
841 for (done = 0; done < count; ) {
842 nb = read(fd, ptr, count - done);
843 if (nb < 0) {
844 if (errno == EINTR)
845 continue;
846 return -1;
847 }
848 if (nb == 0)
849 break;
850 done += nb;
851 ptr += nb;
852 }
853 return done;
854 }
855
856 /* Procedures for locking the serial device using a lock file. */
857 #ifndef LOCK_DIR
858 #ifdef __linux__
859 #define LOCK_DIR "/var/lock"
860 #else
861 #ifdef SVR4
862 #define LOCK_DIR "/var/spool/locks"
863 #else
864 #define LOCK_DIR "/var/spool/lock"
865 #endif
866 #endif
867 #endif /* LOCK_DIR */
868
869 static char lock_file[MAXPATHLEN];
870
871 /*
872 * lock - create a lock file for the named device
873 */
874 int
lock(dev)875 lock(dev)
876 char *dev;
877 {
878 #ifdef LOCKLIB
879 int result;
880
881 result = mklock (dev, (void *) 0);
882 if (result == 0) {
883 strlcpy(lock_file, dev, sizeof(lock_file));
884 return 0;
885 }
886
887 if (result > 0)
888 notice("Device %s is locked by pid %d", dev, result);
889 else
890 error("Can't create lock file %s", lock_file);
891 return -1;
892
893 #else /* LOCKLIB */
894
895 char lock_buffer[12];
896 int fd, pid, n;
897
898 #ifdef SVR4
899 struct stat sbuf;
900
901 if (stat(dev, &sbuf) < 0) {
902 error("Can't get device number for %s: %m", dev);
903 return -1;
904 }
905 if ((sbuf.st_mode & S_IFMT) != S_IFCHR) {
906 error("Can't lock %s: not a character device", dev);
907 return -1;
908 }
909 slprintf(lock_file, sizeof(lock_file), "%s/LK.%03d.%03d.%03d",
910 LOCK_DIR, major(sbuf.st_dev),
911 major(sbuf.st_rdev), minor(sbuf.st_rdev));
912 #else
913 char *p;
914 char lockdev[MAXPATHLEN];
915
916 if ((p = strstr(dev, "dev/")) != NULL) {
917 dev = p + 4;
918 strncpy(lockdev, dev, MAXPATHLEN-1);
919 lockdev[MAXPATHLEN-1] = 0;
920 while ((p = strrchr(lockdev, '/')) != NULL) {
921 *p = '_';
922 }
923 dev = lockdev;
924 } else
925 if ((p = strrchr(dev, '/')) != NULL)
926 dev = p + 1;
927
928 slprintf(lock_file, sizeof(lock_file), "%s/LCK..%s", LOCK_DIR, dev);
929 #endif
930
931 while ((fd = open(lock_file, O_EXCL | O_CREAT | O_RDWR, 0644)) < 0) {
932 if (errno != EEXIST) {
933 error("Can't create lock file %s: %m", lock_file);
934 break;
935 }
936
937 /* Read the lock file to find out who has the device locked. */
938 fd = open(lock_file, O_RDONLY, 0);
939 if (fd < 0) {
940 if (errno == ENOENT) /* This is just a timing problem. */
941 continue;
942 error("Can't open existing lock file %s: %m", lock_file);
943 break;
944 }
945 #ifndef LOCK_BINARY
946 n = read(fd, lock_buffer, 11);
947 #else
948 n = read(fd, &pid, sizeof(pid));
949 #endif /* LOCK_BINARY */
950 close(fd);
951 fd = -1;
952 if (n <= 0) {
953 error("Can't read pid from lock file %s", lock_file);
954 break;
955 }
956
957 /* See if the process still exists. */
958 #ifndef LOCK_BINARY
959 lock_buffer[n] = 0;
960 pid = atoi(lock_buffer);
961 #endif /* LOCK_BINARY */
962 if (pid == getpid())
963 return 1; /* somebody else locked it for us */
964 if (pid == 0
965 || (kill(pid, 0) == -1 && errno == ESRCH)) {
966 if (unlink (lock_file) == 0) {
967 notice("Removed stale lock on %s (pid %d)", dev, pid);
968 continue;
969 }
970 warn("Couldn't remove stale lock on %s", dev);
971 } else
972 notice("Device %s is locked by pid %d", dev, pid);
973 break;
974 }
975
976 if (fd < 0) {
977 lock_file[0] = 0;
978 return -1;
979 }
980
981 pid = getpid();
982 #ifndef LOCK_BINARY
983 slprintf(lock_buffer, sizeof(lock_buffer), "%10d\n", pid);
984 write (fd, lock_buffer, 11);
985 #else
986 write(fd, &pid, sizeof (pid));
987 #endif
988 close(fd);
989 return 0;
990
991 #endif
992 }
993
994 /*
995 * relock - called to update our lockfile when we are about to detach,
996 * thus changing our pid (we fork, the child carries on, and the parent dies).
997 * Note that this is called by the parent, with pid equal to the pid
998 * of the child. This avoids a potential race which would exist if
999 * we had the child rewrite the lockfile (the parent might die first,
1000 * and another process could think the lock was stale if it checked
1001 * between when the parent died and the child rewrote the lockfile).
1002 */
1003 int
relock(pid)1004 relock(pid)
1005 int pid;
1006 {
1007 #ifdef LOCKLIB
1008 /* XXX is there a way to do this? */
1009 return -1;
1010 #else /* LOCKLIB */
1011
1012 int fd;
1013 char lock_buffer[12];
1014
1015 if (lock_file[0] == 0)
1016 return -1;
1017 fd = open(lock_file, O_WRONLY, 0);
1018 if (fd < 0) {
1019 error("Couldn't reopen lock file %s: %m", lock_file);
1020 lock_file[0] = 0;
1021 return -1;
1022 }
1023
1024 #ifndef LOCK_BINARY
1025 slprintf(lock_buffer, sizeof(lock_buffer), "%10d\n", pid);
1026 write (fd, lock_buffer, 11);
1027 #else
1028 write(fd, &pid, sizeof(pid));
1029 #endif /* LOCK_BINARY */
1030 close(fd);
1031 return 0;
1032
1033 #endif /* LOCKLIB */
1034 }
1035
1036 /*
1037 * unlock - remove our lockfile
1038 */
1039 void
unlock()1040 unlock()
1041 {
1042 if (lock_file[0]) {
1043 #ifdef LOCKLIB
1044 (void) rmlock(lock_file, (void *) 0);
1045 #else
1046 unlink(lock_file);
1047 #endif
1048 lock_file[0] = 0;
1049 }
1050 }
1051
1052