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 if (prec >= 0) {
315 n = strnlen((char *)p, prec);
316 } else {
317 n = strlen((char *)p);
318 }
319 }
320 while (n > 0 && buflen > 0) {
321 c = *p++;
322 --n;
323 if (!quoted && c >= 0x80) {
324 OUTCHAR('M');
325 OUTCHAR('-');
326 c -= 0x80;
327 }
328 if (quoted && (c == '"' || c == '\\'))
329 OUTCHAR('\\');
330 if (c < 0x20 || (0x7f <= c && c < 0xa0)) {
331 if (quoted) {
332 OUTCHAR('\\');
333 switch (c) {
334 case '\t': OUTCHAR('t'); break;
335 case '\n': OUTCHAR('n'); break;
336 case '\b': OUTCHAR('b'); break;
337 case '\f': OUTCHAR('f'); break;
338 default:
339 OUTCHAR('x');
340 OUTCHAR(hexchars[c >> 4]);
341 OUTCHAR(hexchars[c & 0xf]);
342 }
343 } else {
344 if (c == '\t')
345 OUTCHAR(c);
346 else {
347 OUTCHAR('^');
348 OUTCHAR(c ^ 0x40);
349 }
350 }
351 } else
352 OUTCHAR(c);
353 }
354 continue;
355 case 'P': /* print PPP packet */
356 bufinfo.ptr = buf;
357 bufinfo.len = buflen + 1;
358 p = va_arg(args, unsigned char *);
359 n = va_arg(args, int);
360 format_packet(p, n, vslp_printer, &bufinfo);
361 buf = bufinfo.ptr;
362 buflen = bufinfo.len - 1;
363 continue;
364 case 'B':
365 p = va_arg(args, unsigned char *);
366 for (n = prec; n > 0; --n) {
367 c = *p++;
368 if (fillch == ' ')
369 OUTCHAR(' ');
370 OUTCHAR(hexchars[(c >> 4) & 0xf]);
371 OUTCHAR(hexchars[c & 0xf]);
372 }
373 continue;
374 default:
375 *buf++ = '%';
376 if (c != '%')
377 --fmt; /* so %z outputs %z etc. */
378 --buflen;
379 continue;
380 }
381 if (base != 0) {
382 str = num + sizeof(num);
383 *--str = 0;
384 while (str > num + neg) {
385 *--str = hexchars[val % base];
386 val = val / base;
387 if (--prec <= 0 && val == 0)
388 break;
389 }
390 switch (neg) {
391 case 1:
392 *--str = '-';
393 break;
394 case 2:
395 *--str = 'x';
396 *--str = '0';
397 break;
398 }
399 len = num + sizeof(num) - 1 - str;
400 } else {
401 len = strlen(str);
402 if (prec >= 0 && len > prec)
403 len = prec;
404 }
405 if (width > 0) {
406 if (width > buflen)
407 width = buflen;
408 if ((n = width - len) > 0) {
409 buflen -= n;
410 for (; n > 0; --n)
411 *buf++ = fillch;
412 }
413 }
414 if (len > buflen)
415 len = buflen;
416 memcpy(buf, str, len);
417 buf += len;
418 buflen -= len;
419 }
420 *buf = 0;
421 return buf - buf0;
422 }
423
424 /*
425 * vslp_printer - used in processing a %P format
426 */
427 static void
vslp_printer(void * arg,char * fmt,...)428 vslp_printer __V((void *arg, char *fmt, ...))
429 {
430 int n;
431 va_list pvar;
432 struct buffer_info *bi;
433
434 #if defined(__STDC__)
435 va_start(pvar, fmt);
436 #else
437 void *arg;
438 char *fmt;
439 va_start(pvar);
440 arg = va_arg(pvar, void *);
441 fmt = va_arg(pvar, char *);
442 #endif
443
444 bi = (struct buffer_info *) arg;
445 n = vslprintf(bi->ptr, bi->len, fmt, pvar);
446 va_end(pvar);
447
448 bi->ptr += n;
449 bi->len -= n;
450 }
451
452 #ifdef unused
453 /*
454 * log_packet - format a packet and log it.
455 */
456
457 void
log_packet(p,len,prefix,level)458 log_packet(p, len, prefix, level)
459 u_char *p;
460 int len;
461 char *prefix;
462 int level;
463 {
464 init_pr_log(prefix, level);
465 format_packet(p, len, pr_log, &level);
466 end_pr_log();
467 }
468 #endif /* unused */
469
470 /*
471 * format_packet - make a readable representation of a packet,
472 * calling `printer(arg, format, ...)' to output it.
473 */
474 static void
format_packet(p,len,printer,arg)475 format_packet(p, len, printer, arg)
476 u_char *p;
477 int len;
478 printer_func printer;
479 void *arg;
480 {
481 int i, n;
482 u_short proto;
483 struct protent *protp;
484
485 if (len >= PPP_HDRLEN && p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) {
486 p += 2;
487 GETSHORT(proto, p);
488 len -= PPP_HDRLEN;
489 for (i = 0; (protp = protocols[i]) != NULL; ++i)
490 if (proto == protp->protocol)
491 break;
492 if (protp != NULL) {
493 printer(arg, "[%s", protp->name);
494 n = (*protp->printpkt)(p, len, printer, arg);
495 printer(arg, "]");
496 p += n;
497 len -= n;
498 } else {
499 for (i = 0; (protp = protocols[i]) != NULL; ++i)
500 if (proto == (protp->protocol & ~0x8000))
501 break;
502 if (protp != 0 && protp->data_name != 0) {
503 printer(arg, "[%s data]", protp->data_name);
504 if (len > 8)
505 printer(arg, "%.8B ...", p);
506 else
507 printer(arg, "%.*B", len, p);
508 len = 0;
509 } else
510 printer(arg, "[proto=0x%x]", proto);
511 }
512 }
513
514 if (len > 32)
515 printer(arg, "%.32B ...", p);
516 else
517 printer(arg, "%.*B", len, p);
518 }
519
520 /*
521 * init_pr_log, end_pr_log - initialize and finish use of pr_log.
522 */
523
524 static char line[256]; /* line to be logged accumulated here */
525 static char *linep; /* current pointer within line */
526 static int llevel; /* level for logging */
527
528 void
init_pr_log(prefix,level)529 init_pr_log(prefix, level)
530 const char *prefix;
531 int level;
532 {
533 linep = line;
534 if (prefix != NULL) {
535 strlcpy(line, prefix, sizeof(line));
536 linep = line + strlen(line);
537 }
538 llevel = level;
539 }
540
541 void
end_pr_log()542 end_pr_log()
543 {
544 if (linep != line) {
545 *linep = 0;
546 log_write(llevel, line);
547 }
548 }
549
550 /*
551 * pr_log - printer routine for outputting to syslog
552 */
553 void
pr_log(void * arg,char * fmt,...)554 pr_log __V((void *arg, char *fmt, ...))
555 {
556 int l, n;
557 va_list pvar;
558 char *p, *eol;
559 char buf[256];
560
561 #if defined(__STDC__)
562 va_start(pvar, fmt);
563 #else
564 void *arg;
565 char *fmt;
566 va_start(pvar);
567 arg = va_arg(pvar, void *);
568 fmt = va_arg(pvar, char *);
569 #endif
570
571 n = vslprintf(buf, sizeof(buf), fmt, pvar);
572 va_end(pvar);
573
574 p = buf;
575 eol = strchr(buf, '\n');
576 if (linep != line) {
577 l = (eol == NULL)? n: eol - buf;
578 if (linep + l < line + sizeof(line)) {
579 if (l > 0) {
580 memcpy(linep, buf, l);
581 linep += l;
582 }
583 if (eol == NULL)
584 return;
585 p = eol + 1;
586 eol = strchr(p, '\n');
587 }
588 *linep = 0;
589 log_write(llevel, line);
590 linep = line;
591 }
592
593 while (eol != NULL) {
594 *eol = 0;
595 log_write(llevel, p);
596 p = eol + 1;
597 eol = strchr(p, '\n');
598 }
599
600 /* assumes sizeof(buf) <= sizeof(line) */
601 l = buf + n - p;
602 if (l > 0) {
603 memcpy(line, p, n);
604 linep = line + l;
605 }
606 }
607
608 /*
609 * print_string - print a readable representation of a string using
610 * printer.
611 */
612 void
print_string(p,len,printer,arg)613 print_string(p, len, printer, arg)
614 char *p;
615 int len;
616 printer_func printer;
617 void *arg;
618 {
619 int c;
620
621 printer(arg, "\"");
622 for (; len > 0; --len) {
623 c = *p++;
624 if (' ' <= c && c <= '~') {
625 if (c == '\\' || c == '"')
626 printer(arg, "\\");
627 printer(arg, "%c", c);
628 } else {
629 switch (c) {
630 case '\n':
631 printer(arg, "\\n");
632 break;
633 case '\r':
634 printer(arg, "\\r");
635 break;
636 case '\t':
637 printer(arg, "\\t");
638 break;
639 default:
640 printer(arg, "\\%.3o", c);
641 }
642 }
643 }
644 printer(arg, "\"");
645 }
646
647 /*
648 * logit - does the hard work for fatal et al.
649 */
650 static void
logit(level,fmt,args)651 logit(level, fmt, args)
652 int level;
653 char *fmt;
654 va_list args;
655 {
656 char buf[1024];
657
658 vslprintf(buf, sizeof(buf), fmt, args);
659 log_write(level, buf);
660 }
661
662 static void
log_write(level,buf)663 log_write(level, buf)
664 int level;
665 char *buf;
666 {
667 syslog(level, "%s", buf);
668 if (log_to_fd >= 0 && (level != LOG_DEBUG || debug)) {
669 int n = strlen(buf);
670
671 if (n > 0 && buf[n-1] == '\n')
672 --n;
673 if (write(log_to_fd, buf, n) != n
674 || write(log_to_fd, "\n", 1) != 1)
675 log_to_fd = -1;
676 }
677 }
678
679 /*
680 * fatal - log an error message and die horribly.
681 */
682 void
fatal(char * fmt,...)683 fatal __V((char *fmt, ...))
684 {
685 va_list pvar;
686
687 #if defined(__STDC__)
688 va_start(pvar, fmt);
689 #else
690 char *fmt;
691 va_start(pvar);
692 fmt = va_arg(pvar, char *);
693 #endif
694
695 logit(LOG_ERR, fmt, pvar);
696 va_end(pvar);
697
698 die(1); /* as promised */
699 }
700
701 /*
702 * error - log an error message.
703 */
704 void
error(char * fmt,...)705 error __V((char *fmt, ...))
706 {
707 va_list pvar;
708
709 #if defined(__STDC__)
710 va_start(pvar, fmt);
711 #else
712 char *fmt;
713 va_start(pvar);
714 fmt = va_arg(pvar, char *);
715 #endif
716
717 logit(LOG_ERR, fmt, pvar);
718 va_end(pvar);
719 ++error_count;
720 }
721
722 /*
723 * warn - log a warning message.
724 */
725 void
warn(char * fmt,...)726 warn __V((char *fmt, ...))
727 {
728 va_list pvar;
729
730 #if defined(__STDC__)
731 va_start(pvar, fmt);
732 #else
733 char *fmt;
734 va_start(pvar);
735 fmt = va_arg(pvar, char *);
736 #endif
737
738 logit(LOG_WARNING, fmt, pvar);
739 va_end(pvar);
740 }
741
742 /*
743 * notice - log a notice-level message.
744 */
745 void
notice(char * fmt,...)746 notice __V((char *fmt, ...))
747 {
748 va_list pvar;
749
750 #if defined(__STDC__)
751 va_start(pvar, fmt);
752 #else
753 char *fmt;
754 va_start(pvar);
755 fmt = va_arg(pvar, char *);
756 #endif
757
758 logit(LOG_NOTICE, fmt, pvar);
759 va_end(pvar);
760 }
761
762 /*
763 * info - log an informational message.
764 */
765 void
info(char * fmt,...)766 info __V((char *fmt, ...))
767 {
768 va_list pvar;
769
770 #if defined(__STDC__)
771 va_start(pvar, fmt);
772 #else
773 char *fmt;
774 va_start(pvar);
775 fmt = va_arg(pvar, char *);
776 #endif
777
778 logit(LOG_INFO, fmt, pvar);
779 va_end(pvar);
780 }
781
782 /*
783 * dbglog - log a debug message.
784 */
785 void
dbglog(char * fmt,...)786 dbglog __V((char *fmt, ...))
787 {
788 va_list pvar;
789
790 #if defined(__STDC__)
791 va_start(pvar, fmt);
792 #else
793 char *fmt;
794 va_start(pvar);
795 fmt = va_arg(pvar, char *);
796 #endif
797
798 logit(LOG_DEBUG, fmt, pvar);
799 va_end(pvar);
800 }
801
802 /*
803 * dump_packet - print out a packet in readable form if it is interesting.
804 * Assumes len >= PPP_HDRLEN.
805 */
806 void
dump_packet(const char * tag,unsigned char * p,int len)807 dump_packet(const char *tag, unsigned char *p, int len)
808 {
809 int proto;
810
811 if (!debug)
812 return;
813
814 /*
815 * don't print LCP echo request/reply packets if debug <= 1
816 * and the link is up.
817 */
818 proto = (p[2] << 8) + p[3];
819 if (debug <= 1 && unsuccess == 0 && proto == PPP_LCP
820 && len >= PPP_HDRLEN + HEADERLEN) {
821 unsigned char *lcp = p + PPP_HDRLEN;
822 int l = (lcp[2] << 8) + lcp[3];
823
824 if ((lcp[0] == ECHOREQ || lcp[0] == ECHOREP)
825 && l >= HEADERLEN && l <= len - PPP_HDRLEN)
826 return;
827 }
828
829 dbglog("%s %P", tag, p, len);
830 }
831
832 /*
833 * complete_read - read a full `count' bytes from fd,
834 * unless end-of-file or an error other than EINTR is encountered.
835 */
836 ssize_t
complete_read(int fd,void * buf,size_t count)837 complete_read(int fd, void *buf, size_t count)
838 {
839 size_t done;
840 ssize_t nb;
841 char *ptr = buf;
842
843 for (done = 0; done < count; ) {
844 nb = read(fd, ptr, count - done);
845 if (nb < 0) {
846 if (errno == EINTR)
847 continue;
848 return -1;
849 }
850 if (nb == 0)
851 break;
852 done += nb;
853 ptr += nb;
854 }
855 return done;
856 }
857
858 /* Procedures for locking the serial device using a lock file. */
859 #ifndef LOCK_DIR
860 #ifdef __linux__
861 #define LOCK_DIR "/var/lock"
862 #else
863 #ifdef SVR4
864 #define LOCK_DIR "/var/spool/locks"
865 #else
866 #define LOCK_DIR "/var/spool/lock"
867 #endif
868 #endif
869 #endif /* LOCK_DIR */
870
871 static char lock_file[MAXPATHLEN];
872
873 /*
874 * lock - create a lock file for the named device
875 */
876 int
lock(dev)877 lock(dev)
878 char *dev;
879 {
880 #ifdef LOCKLIB
881 int result;
882
883 result = mklock (dev, (void *) 0);
884 if (result == 0) {
885 strlcpy(lock_file, dev, sizeof(lock_file));
886 return 0;
887 }
888
889 if (result > 0)
890 notice("Device %s is locked by pid %d", dev, result);
891 else
892 error("Can't create lock file %s", lock_file);
893 return -1;
894
895 #else /* LOCKLIB */
896
897 char lock_buffer[12];
898 int fd, pid, n;
899
900 #ifdef SVR4
901 struct stat sbuf;
902
903 if (stat(dev, &sbuf) < 0) {
904 error("Can't get device number for %s: %m", dev);
905 return -1;
906 }
907 if ((sbuf.st_mode & S_IFMT) != S_IFCHR) {
908 error("Can't lock %s: not a character device", dev);
909 return -1;
910 }
911 slprintf(lock_file, sizeof(lock_file), "%s/LK.%03d.%03d.%03d",
912 LOCK_DIR, major(sbuf.st_dev),
913 major(sbuf.st_rdev), minor(sbuf.st_rdev));
914 #else
915 char *p;
916 char lockdev[MAXPATHLEN];
917
918 if ((p = strstr(dev, "dev/")) != NULL) {
919 dev = p + 4;
920 strncpy(lockdev, dev, MAXPATHLEN-1);
921 lockdev[MAXPATHLEN-1] = 0;
922 while ((p = strrchr(lockdev, '/')) != NULL) {
923 *p = '_';
924 }
925 dev = lockdev;
926 } else
927 if ((p = strrchr(dev, '/')) != NULL)
928 dev = p + 1;
929
930 slprintf(lock_file, sizeof(lock_file), "%s/LCK..%s", LOCK_DIR, dev);
931 #endif
932
933 while ((fd = open(lock_file, O_EXCL | O_CREAT | O_RDWR, 0644)) < 0) {
934 if (errno != EEXIST) {
935 error("Can't create lock file %s: %m", lock_file);
936 break;
937 }
938
939 /* Read the lock file to find out who has the device locked. */
940 fd = open(lock_file, O_RDONLY, 0);
941 if (fd < 0) {
942 if (errno == ENOENT) /* This is just a timing problem. */
943 continue;
944 error("Can't open existing lock file %s: %m", lock_file);
945 break;
946 }
947 #ifndef LOCK_BINARY
948 n = read(fd, lock_buffer, 11);
949 #else
950 n = read(fd, &pid, sizeof(pid));
951 #endif /* LOCK_BINARY */
952 close(fd);
953 fd = -1;
954 if (n <= 0) {
955 error("Can't read pid from lock file %s", lock_file);
956 break;
957 }
958
959 /* See if the process still exists. */
960 #ifndef LOCK_BINARY
961 lock_buffer[n] = 0;
962 pid = atoi(lock_buffer);
963 #endif /* LOCK_BINARY */
964 if (pid == getpid())
965 return 1; /* somebody else locked it for us */
966 if (pid == 0
967 || (kill(pid, 0) == -1 && errno == ESRCH)) {
968 if (unlink (lock_file) == 0) {
969 notice("Removed stale lock on %s (pid %d)", dev, pid);
970 continue;
971 }
972 warn("Couldn't remove stale lock on %s", dev);
973 } else
974 notice("Device %s is locked by pid %d", dev, pid);
975 break;
976 }
977
978 if (fd < 0) {
979 lock_file[0] = 0;
980 return -1;
981 }
982
983 pid = getpid();
984 #ifndef LOCK_BINARY
985 slprintf(lock_buffer, sizeof(lock_buffer), "%10d\n", pid);
986 write (fd, lock_buffer, 11);
987 #else
988 write(fd, &pid, sizeof (pid));
989 #endif
990 close(fd);
991 return 0;
992
993 #endif
994 }
995
996 /*
997 * relock - called to update our lockfile when we are about to detach,
998 * thus changing our pid (we fork, the child carries on, and the parent dies).
999 * Note that this is called by the parent, with pid equal to the pid
1000 * of the child. This avoids a potential race which would exist if
1001 * we had the child rewrite the lockfile (the parent might die first,
1002 * and another process could think the lock was stale if it checked
1003 * between when the parent died and the child rewrote the lockfile).
1004 */
1005 int
relock(pid)1006 relock(pid)
1007 int pid;
1008 {
1009 #ifdef LOCKLIB
1010 /* XXX is there a way to do this? */
1011 return -1;
1012 #else /* LOCKLIB */
1013
1014 int fd;
1015 char lock_buffer[12];
1016
1017 if (lock_file[0] == 0)
1018 return -1;
1019 fd = open(lock_file, O_WRONLY, 0);
1020 if (fd < 0) {
1021 error("Couldn't reopen lock file %s: %m", lock_file);
1022 lock_file[0] = 0;
1023 return -1;
1024 }
1025
1026 #ifndef LOCK_BINARY
1027 slprintf(lock_buffer, sizeof(lock_buffer), "%10d\n", pid);
1028 write (fd, lock_buffer, 11);
1029 #else
1030 write(fd, &pid, sizeof(pid));
1031 #endif /* LOCK_BINARY */
1032 close(fd);
1033 return 0;
1034
1035 #endif /* LOCKLIB */
1036 }
1037
1038 /*
1039 * unlock - remove our lockfile
1040 */
1041 void
unlock()1042 unlock()
1043 {
1044 if (lock_file[0]) {
1045 #ifdef LOCKLIB
1046 (void) rmlock(lock_file, (void *) 0);
1047 #else
1048 unlink(lock_file);
1049 #endif
1050 lock_file[0] = 0;
1051 }
1052 }
1053
1054