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 1.24 2004/11/04 10:02:26 paulus Exp $"
32 #define LOG_TAG "pppd"
33
34 #include <stdio.h>
35 #include <ctype.h>
36 #include <stdlib.h>
37 #include <string.h>
38 #include <unistd.h>
39 #include <signal.h>
40 #include <errno.h>
41 #include <fcntl.h>
42 #include <syslog.h>
43 #include <netdb.h>
44 #include <time.h>
45 #include <utmp.h>
46 #include <pwd.h>
47 #include <sys/param.h>
48 #include <sys/types.h>
49 #include <sys/wait.h>
50 #include <sys/time.h>
51 #include <sys/resource.h>
52 #include <sys/stat.h>
53 #include <sys/socket.h>
54 #include <netinet/in.h>
55 #ifdef SVR4
56 #include <sys/mkdev.h>
57 #endif
58
59 #include "pppd.h"
60 #include "fsm.h"
61 #include "lcp.h"
62
63 #ifdef ANDROID_CHANGES
64 #include <android/log.h>
65 #endif
66
67 static const char rcsid[] = RCSID;
68
69 #if defined(SUNOS4)
70 extern char *strerror();
71 #endif
72
73 static void logit __P((int, char *, va_list));
74 static void log_write __P((int, char *));
75 static void vslp_printer __P((void *, char *, ...));
76 static void format_packet __P((u_char *, int, void (*) (void *, char *, ...),
77 void *));
78
79 struct buffer_info {
80 char *ptr;
81 int len;
82 };
83
84 #if !defined(ANDROID_CHANGES)
85
86 /*
87 * strlcpy - like strcpy/strncpy, doesn't overflow destination buffer,
88 * always leaves destination null-terminated (for len > 0).
89 */
90 size_t
strlcpy(dest,src,len)91 strlcpy(dest, src, len)
92 char *dest;
93 const char *src;
94 size_t len;
95 {
96 size_t ret = strlen(src);
97
98 if (len != 0) {
99 if (ret < len)
100 strcpy(dest, src);
101 else {
102 strncpy(dest, src, len - 1);
103 dest[len-1] = 0;
104 }
105 }
106 return ret;
107 }
108
109 /*
110 * strlcat - like strcat/strncat, doesn't overflow destination buffer,
111 * always leaves destination null-terminated (for len > 0).
112 */
113 size_t
strlcat(dest,src,len)114 strlcat(dest, src, len)
115 char *dest;
116 const char *src;
117 size_t len;
118 {
119 size_t dlen = strlen(dest);
120
121 return dlen + strlcpy(dest + dlen, src, (len > dlen? len - dlen: 0));
122 }
123 #endif
124
125
126 /*
127 * slprintf - format a message into a buffer. Like sprintf except we
128 * also specify the length of the output buffer, and we handle
129 * %m (error message), %v (visible string),
130 * %q (quoted string), %t (current time) and %I (IP address) formats.
131 * Doesn't do floating-point formats.
132 * Returns the number of chars put into buf.
133 */
134 int
slprintf(char * buf,int buflen,char * fmt,...)135 slprintf __V((char *buf, int buflen, char *fmt, ...))
136 {
137 va_list args;
138 int n;
139
140 #if defined(__STDC__)
141 va_start(args, fmt);
142 #else
143 char *buf;
144 int buflen;
145 char *fmt;
146 va_start(args);
147 buf = va_arg(args, char *);
148 buflen = va_arg(args, int);
149 fmt = va_arg(args, char *);
150 #endif
151 n = vslprintf(buf, buflen, fmt, args);
152 va_end(args);
153 return n;
154 }
155
156 /*
157 * vslprintf - like slprintf, takes a va_list instead of a list of args.
158 */
159 #define OUTCHAR(c) (buflen > 0? (--buflen, *buf++ = (c)): 0)
160
161 int
vslprintf(buf,buflen,fmt,args)162 vslprintf(buf, buflen, fmt, args)
163 char *buf;
164 int buflen;
165 char *fmt;
166 va_list args;
167 {
168 int c, i, n;
169 int width, prec, fillch;
170 int base, len, neg, quoted;
171 unsigned long val = 0;
172 char *str, *f, *buf0;
173 unsigned char *p;
174 char num[32];
175 time_t t;
176 u_int32_t ip;
177 static char hexchars[] = "0123456789abcdef";
178 struct buffer_info bufinfo;
179
180 buf0 = buf;
181 --buflen;
182 while (buflen > 0) {
183 for (f = fmt; *f != '%' && *f != 0; ++f)
184 ;
185 if (f > fmt) {
186 len = f - fmt;
187 if (len > buflen)
188 len = buflen;
189 memcpy(buf, fmt, len);
190 buf += len;
191 buflen -= len;
192 fmt = f;
193 }
194 if (*fmt == 0)
195 break;
196 c = *++fmt;
197 width = 0;
198 prec = -1;
199 fillch = ' ';
200 if (c == '0') {
201 fillch = '0';
202 c = *++fmt;
203 }
204 if (c == '*') {
205 width = va_arg(args, int);
206 c = *++fmt;
207 } else {
208 while (isdigit(c)) {
209 width = width * 10 + c - '0';
210 c = *++fmt;
211 }
212 }
213 if (c == '.') {
214 c = *++fmt;
215 if (c == '*') {
216 prec = va_arg(args, int);
217 c = *++fmt;
218 } else {
219 prec = 0;
220 while (isdigit(c)) {
221 prec = prec * 10 + c - '0';
222 c = *++fmt;
223 }
224 }
225 }
226 str = 0;
227 base = 0;
228 neg = 0;
229 ++fmt;
230 switch (c) {
231 case 'l':
232 c = *fmt++;
233 switch (c) {
234 case 'd':
235 val = va_arg(args, long);
236 if ((long)val < 0) {
237 neg = 1;
238 val = (unsigned long)(-(long)val);
239 }
240 base = 10;
241 break;
242 case 'u':
243 val = va_arg(args, unsigned long);
244 base = 10;
245 break;
246 default:
247 *buf++ = '%'; --buflen;
248 *buf++ = 'l'; --buflen;
249 --fmt; /* so %lz outputs %lz etc. */
250 continue;
251 }
252 break;
253 case 'd':
254 i = va_arg(args, int);
255 if (i < 0) {
256 neg = 1;
257 val = -i;
258 } else
259 val = i;
260 base = 10;
261 break;
262 case 'u':
263 val = va_arg(args, unsigned int);
264 base = 10;
265 break;
266 case 'o':
267 val = va_arg(args, unsigned int);
268 base = 8;
269 break;
270 case 'x':
271 case 'X':
272 val = va_arg(args, unsigned int);
273 base = 16;
274 break;
275 case 'p':
276 val = (unsigned long) va_arg(args, void *);
277 base = 16;
278 neg = 2;
279 break;
280 case 's':
281 str = va_arg(args, char *);
282 break;
283 case 'c':
284 num[0] = va_arg(args, int);
285 num[1] = 0;
286 str = num;
287 break;
288 case 'm':
289 str = strerror(errno);
290 break;
291 case 'I':
292 ip = va_arg(args, u_int32_t);
293 ip = ntohl(ip);
294 slprintf(num, sizeof(num), "%d.%d.%d.%d", (ip >> 24) & 0xff,
295 (ip >> 16) & 0xff, (ip >> 8) & 0xff, ip & 0xff);
296 str = num;
297 break;
298 #if 0 /* not used, and breaks on S/390, apparently */
299 case 'r':
300 f = va_arg(args, char *);
301 #ifndef __powerpc__
302 n = vslprintf(buf, buflen + 1, f, va_arg(args, va_list));
303 #else
304 /* On the powerpc, a va_list is an array of 1 structure */
305 n = vslprintf(buf, buflen + 1, f, va_arg(args, void *));
306 #endif
307 buf += n;
308 buflen -= n;
309 continue;
310 #endif
311 case 't':
312 time(&t);
313 str = ctime(&t);
314 str += 4; /* chop off the day name */
315 str[15] = 0; /* chop off year and newline */
316 break;
317 case 'v': /* "visible" string */
318 case 'q': /* quoted string */
319 quoted = c == 'q';
320 p = va_arg(args, unsigned char *);
321 if (fillch == '0' && prec >= 0) {
322 n = prec;
323 } else {
324 n = strlen((char *)p);
325 if (prec >= 0 && n > prec)
326 n = prec;
327 }
328 while (n > 0 && buflen > 0) {
329 c = *p++;
330 --n;
331 if (!quoted && c >= 0x80) {
332 OUTCHAR('M');
333 OUTCHAR('-');
334 c -= 0x80;
335 }
336 if (quoted && (c == '"' || c == '\\'))
337 OUTCHAR('\\');
338 if (c < 0x20 || (0x7f <= c && c < 0xa0)) {
339 if (quoted) {
340 OUTCHAR('\\');
341 switch (c) {
342 case '\t': OUTCHAR('t'); break;
343 case '\n': OUTCHAR('n'); break;
344 case '\b': OUTCHAR('b'); break;
345 case '\f': OUTCHAR('f'); break;
346 default:
347 OUTCHAR('x');
348 OUTCHAR(hexchars[c >> 4]);
349 OUTCHAR(hexchars[c & 0xf]);
350 }
351 } else {
352 if (c == '\t')
353 OUTCHAR(c);
354 else {
355 OUTCHAR('^');
356 OUTCHAR(c ^ 0x40);
357 }
358 }
359 } else
360 OUTCHAR(c);
361 }
362 continue;
363 case 'P': /* print PPP packet */
364 bufinfo.ptr = buf;
365 bufinfo.len = buflen + 1;
366 p = va_arg(args, unsigned char *);
367 n = va_arg(args, int);
368 format_packet(p, n, vslp_printer, &bufinfo);
369 buf = bufinfo.ptr;
370 buflen = bufinfo.len - 1;
371 continue;
372 case 'B':
373 p = va_arg(args, unsigned char *);
374 for (n = prec; n > 0; --n) {
375 c = *p++;
376 if (fillch == ' ')
377 OUTCHAR(' ');
378 OUTCHAR(hexchars[(c >> 4) & 0xf]);
379 OUTCHAR(hexchars[c & 0xf]);
380 }
381 continue;
382 default:
383 *buf++ = '%';
384 if (c != '%')
385 --fmt; /* so %z outputs %z etc. */
386 --buflen;
387 continue;
388 }
389 if (base != 0) {
390 str = num + sizeof(num);
391 *--str = 0;
392 while (str > num + neg) {
393 *--str = hexchars[val % base];
394 val = val / base;
395 if (--prec <= 0 && val == 0)
396 break;
397 }
398 switch (neg) {
399 case 1:
400 *--str = '-';
401 break;
402 case 2:
403 *--str = 'x';
404 *--str = '0';
405 break;
406 }
407 len = num + sizeof(num) - 1 - str;
408 } else {
409 len = strlen(str);
410 if (prec >= 0 && len > prec)
411 len = prec;
412 }
413 if (width > 0) {
414 if (width > buflen)
415 width = buflen;
416 if ((n = width - len) > 0) {
417 buflen -= n;
418 for (; n > 0; --n)
419 *buf++ = fillch;
420 }
421 }
422 if (len > buflen)
423 len = buflen;
424 memcpy(buf, str, len);
425 buf += len;
426 buflen -= len;
427 }
428 *buf = 0;
429 return buf - buf0;
430 }
431
432 /*
433 * vslp_printer - used in processing a %P format
434 */
435 static void
vslp_printer(void * arg,char * fmt,...)436 vslp_printer __V((void *arg, char *fmt, ...))
437 {
438 int n;
439 va_list pvar;
440 struct buffer_info *bi;
441
442 #if defined(__STDC__)
443 va_start(pvar, fmt);
444 #else
445 void *arg;
446 char *fmt;
447 va_start(pvar);
448 arg = va_arg(pvar, void *);
449 fmt = va_arg(pvar, char *);
450 #endif
451
452 bi = (struct buffer_info *) arg;
453 n = vslprintf(bi->ptr, bi->len, fmt, pvar);
454 va_end(pvar);
455
456 bi->ptr += n;
457 bi->len -= n;
458 }
459
460 #ifdef unused
461 /*
462 * log_packet - format a packet and log it.
463 */
464
465 void
log_packet(p,len,prefix,level)466 log_packet(p, len, prefix, level)
467 u_char *p;
468 int len;
469 char *prefix;
470 int level;
471 {
472 init_pr_log(prefix, level);
473 format_packet(p, len, pr_log, &level);
474 end_pr_log();
475 }
476 #endif /* unused */
477
478 /*
479 * format_packet - make a readable representation of a packet,
480 * calling `printer(arg, format, ...)' to output it.
481 */
482 static void
format_packet(p,len,printer,arg)483 format_packet(p, len, printer, arg)
484 u_char *p;
485 int len;
486 void (*printer) __P((void *, char *, ...));
487 void *arg;
488 {
489 int i, n;
490 u_short proto;
491 struct protent *protp;
492
493 if (len >= PPP_HDRLEN && p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) {
494 p += 2;
495 GETSHORT(proto, p);
496 len -= PPP_HDRLEN;
497 for (i = 0; (protp = protocols[i]) != NULL; ++i)
498 if (proto == protp->protocol)
499 break;
500 if (protp != NULL) {
501 printer(arg, "[%s", protp->name);
502 n = (*protp->printpkt)(p, len, printer, arg);
503 printer(arg, "]");
504 p += n;
505 len -= n;
506 } else {
507 for (i = 0; (protp = protocols[i]) != NULL; ++i)
508 if (proto == (protp->protocol & ~0x8000))
509 break;
510 if (protp != 0 && protp->data_name != 0) {
511 printer(arg, "[%s data]", protp->data_name);
512 if (len > 8)
513 printer(arg, "%.8B ...", p);
514 else
515 printer(arg, "%.*B", len, p);
516 len = 0;
517 } else
518 printer(arg, "[proto=0x%x]", proto);
519 }
520 }
521
522 if (len > 32)
523 printer(arg, "%.32B ...", p);
524 else
525 printer(arg, "%.*B", len, p);
526 }
527
528 /*
529 * init_pr_log, end_pr_log - initialize and finish use of pr_log.
530 */
531
532 static char line[256]; /* line to be logged accumulated here */
533 static char *linep; /* current pointer within line */
534 static int llevel; /* level for logging */
535
536 void
init_pr_log(prefix,level)537 init_pr_log(prefix, level)
538 char *prefix;
539 int level;
540 {
541 linep = line;
542 if (prefix != NULL) {
543 strlcpy(line, prefix, sizeof(line));
544 linep = line + strlen(line);
545 }
546 llevel = level;
547 }
548
549 void
end_pr_log()550 end_pr_log()
551 {
552 if (linep != line) {
553 *linep = 0;
554 log_write(llevel, line);
555 }
556 }
557
558 /*
559 * pr_log - printer routine for outputting to syslog
560 */
561 void
pr_log(void * arg,char * fmt,...)562 pr_log __V((void *arg, char *fmt, ...))
563 {
564 int l, n;
565 va_list pvar;
566 char *p, *eol;
567 char buf[256];
568
569 #if defined(__STDC__)
570 va_start(pvar, fmt);
571 #else
572 void *arg;
573 char *fmt;
574 va_start(pvar);
575 arg = va_arg(pvar, void *);
576 fmt = va_arg(pvar, char *);
577 #endif
578
579 n = vslprintf(buf, sizeof(buf), fmt, pvar);
580 va_end(pvar);
581
582 p = buf;
583 eol = strchr(buf, '\n');
584 if (linep != line) {
585 l = (eol == NULL)? n: eol - buf;
586 if (linep + l < line + sizeof(line)) {
587 if (l > 0) {
588 memcpy(linep, buf, l);
589 linep += l;
590 }
591 if (eol == NULL)
592 return;
593 p = eol + 1;
594 eol = strchr(p, '\n');
595 }
596 *linep = 0;
597 log_write(llevel, line);
598 linep = line;
599 }
600
601 while (eol != NULL) {
602 *eol = 0;
603 log_write(llevel, p);
604 p = eol + 1;
605 eol = strchr(p, '\n');
606 }
607
608 /* assumes sizeof(buf) <= sizeof(line) */
609 l = buf + n - p;
610 if (l > 0) {
611 memcpy(line, p, n);
612 linep = line + l;
613 }
614 }
615
616 /*
617 * print_string - print a readable representation of a string using
618 * printer.
619 */
620 void
print_string(p,len,printer,arg)621 print_string(p, len, printer, arg)
622 char *p;
623 int len;
624 void (*printer) __P((void *, char *, ...));
625 void *arg;
626 {
627 int c;
628
629 printer(arg, "\"");
630 for (; len > 0; --len) {
631 c = *p++;
632 if (' ' <= c && c <= '~') {
633 if (c == '\\' || c == '"')
634 printer(arg, "\\");
635 printer(arg, "%c", c);
636 } else {
637 switch (c) {
638 case '\n':
639 printer(arg, "\\n");
640 break;
641 case '\r':
642 printer(arg, "\\r");
643 break;
644 case '\t':
645 printer(arg, "\\t");
646 break;
647 default:
648 printer(arg, "\\%.3o", c);
649 }
650 }
651 }
652 printer(arg, "\"");
653 }
654
655 /*
656 * logit - does the hard work for fatal et al.
657 */
658 static void
logit(level,fmt,args)659 logit(level, fmt, args)
660 int level;
661 char *fmt;
662 va_list args;
663 {
664 int n;
665 char buf[1024];
666
667 n = vslprintf(buf, sizeof(buf), fmt, args);
668 log_write(level, buf);
669 }
670
671 #ifdef ANDROID_CHANGES
672
673 #if LOG_PRIMASK != 7
674 #error Syslog.h has been changed! Please fix this table!
675 #endif
676
677 static int syslog_to_android[] = {
678 [LOG_EMERG] = ANDROID_LOG_FATAL,
679 [LOG_ALERT] = ANDROID_LOG_FATAL,
680 [LOG_CRIT] = ANDROID_LOG_FATAL,
681 [LOG_ERR] = ANDROID_LOG_ERROR,
682 [LOG_WARNING] = ANDROID_LOG_WARN,
683 [LOG_NOTICE] = ANDROID_LOG_INFO,
684 [LOG_INFO] = ANDROID_LOG_INFO,
685 [LOG_DEBUG] = ANDROID_LOG_DEBUG,
686 };
687
688 #endif
689
690 static void
log_write(level,buf)691 log_write(level, buf)
692 int level;
693 char *buf;
694 {
695 #ifndef ANDROID_CHANGES
696 syslog(level, "%s", buf);
697
698 fprintf(stderr, buf);
699
700 if (log_to_fd >= 0 && (level != LOG_DEBUG || debug)) {
701 int n = strlen(buf);
702
703 if (n > 0 && buf[n-1] == '\n')
704 --n;
705 if (write(log_to_fd, buf, n) != n
706 || write(log_to_fd, "\n", 1) != 1)
707 log_to_fd = -1;
708 }
709 #else
710 __android_log_write(syslog_to_android[level], LOG_TAG, buf);
711 #endif
712 }
713
714 /*
715 * fatal - log an error message and die horribly.
716 */
717 void
fatal(char * fmt,...)718 fatal __V((char *fmt, ...))
719 {
720 va_list pvar;
721
722 #if defined(__STDC__)
723 va_start(pvar, fmt);
724 #else
725 char *fmt;
726 va_start(pvar);
727 fmt = va_arg(pvar, char *);
728 #endif
729
730 logit(LOG_ERR, fmt, pvar);
731 va_end(pvar);
732
733 die(1); /* as promised */
734 }
735
736 /*
737 * error - log an error message.
738 */
739 void
error(char * fmt,...)740 error __V((char *fmt, ...))
741 {
742 va_list pvar;
743
744 #if defined(__STDC__)
745 va_start(pvar, fmt);
746 #else
747 char *fmt;
748 va_start(pvar);
749 fmt = va_arg(pvar, char *);
750 #endif
751
752 logit(LOG_ERR, fmt, pvar);
753 va_end(pvar);
754 ++error_count;
755 }
756
757 /*
758 * warn - log a warning message.
759 */
760 void
warn(char * fmt,...)761 warn __V((char *fmt, ...))
762 {
763 va_list pvar;
764
765 #if defined(__STDC__)
766 va_start(pvar, fmt);
767 #else
768 char *fmt;
769 va_start(pvar);
770 fmt = va_arg(pvar, char *);
771 #endif
772
773 logit(LOG_WARNING, fmt, pvar);
774 va_end(pvar);
775 }
776
777 /*
778 * notice - log a notice-level message.
779 */
780 void
notice(char * fmt,...)781 notice __V((char *fmt, ...))
782 {
783 va_list pvar;
784
785 #if defined(__STDC__)
786 va_start(pvar, fmt);
787 #else
788 char *fmt;
789 va_start(pvar);
790 fmt = va_arg(pvar, char *);
791 #endif
792
793 logit(LOG_NOTICE, fmt, pvar);
794 va_end(pvar);
795 }
796
797 /*
798 * info - log an informational message.
799 */
800 void
info(char * fmt,...)801 info __V((char *fmt, ...))
802 {
803 va_list pvar;
804
805 #if defined(__STDC__)
806 va_start(pvar, fmt);
807 #else
808 char *fmt;
809 va_start(pvar);
810 fmt = va_arg(pvar, char *);
811 #endif
812
813 logit(LOG_INFO, fmt, pvar);
814 va_end(pvar);
815 }
816
817 /*
818 * dbglog - log a debug message.
819 */
820 void
dbglog(char * fmt,...)821 dbglog __V((char *fmt, ...))
822 {
823 va_list pvar;
824
825 #if defined(__STDC__)
826 va_start(pvar, fmt);
827 #else
828 char *fmt;
829 va_start(pvar);
830 fmt = va_arg(pvar, char *);
831 #endif
832
833 logit(LOG_DEBUG, fmt, pvar);
834 va_end(pvar);
835 }
836
837 /*
838 * dump_packet - print out a packet in readable form if it is interesting.
839 * Assumes len >= PPP_HDRLEN.
840 */
841 void
dump_packet(const char * tag,unsigned char * p,int len)842 dump_packet(const char *tag, unsigned char *p, int len)
843 {
844 int proto;
845
846 if (!debug)
847 return;
848
849 /*
850 * don't print LCP echo request/reply packets if debug <= 1
851 * and the link is up.
852 */
853 proto = (p[2] << 8) + p[3];
854 if (debug <= 1 && unsuccess == 0 && proto == PPP_LCP
855 && len >= PPP_HDRLEN + HEADERLEN) {
856 unsigned char *lcp = p + PPP_HDRLEN;
857 int l = (lcp[2] << 8) + lcp[3];
858
859 if ((lcp[0] == ECHOREQ || lcp[0] == ECHOREP)
860 && l >= HEADERLEN && l <= len - PPP_HDRLEN)
861 return;
862 }
863
864 dbglog("%s %P", tag, p, len);
865 }
866
867 /*
868 * complete_read - read a full `count' bytes from fd,
869 * unless end-of-file or an error other than EINTR is encountered.
870 */
871 ssize_t
complete_read(int fd,void * buf,size_t count)872 complete_read(int fd, void *buf, size_t count)
873 {
874 size_t done;
875 ssize_t nb;
876 char *ptr = buf;
877
878 for (done = 0; done < count; ) {
879 nb = read(fd, ptr, count - done);
880 if (nb < 0) {
881 if (errno == EINTR)
882 continue;
883 return -1;
884 }
885 if (nb == 0)
886 break;
887 done += nb;
888 ptr += nb;
889 }
890 return done;
891 }
892
893 /* Procedures for locking the serial device using a lock file. */
894 #ifndef LOCK_DIR
895 #ifdef __linux__
896 #define LOCK_DIR "/var/lock"
897 #else
898 #ifdef SVR4
899 #define LOCK_DIR "/var/spool/locks"
900 #else
901 #define LOCK_DIR "/var/spool/lock"
902 #endif
903 #endif
904 #endif /* LOCK_DIR */
905
906 static char lock_file[MAXPATHLEN];
907
908 /*
909 * lock - create a lock file for the named device
910 */
911 int
lock(dev)912 lock(dev)
913 char *dev;
914 {
915 #ifdef LOCKLIB
916 int result;
917
918 result = mklock (dev, (void *) 0);
919 if (result == 0) {
920 strlcpy(lock_file, dev, sizeof(lock_file));
921 return 0;
922 }
923
924 if (result > 0)
925 notice("Device %s is locked by pid %d", dev, result);
926 else
927 error("Can't create lock file %s", lock_file);
928 return -1;
929
930 #else /* LOCKLIB */
931
932 char lock_buffer[12];
933 int fd, pid, n;
934
935 #ifdef SVR4
936 struct stat sbuf;
937
938 if (stat(dev, &sbuf) < 0) {
939 error("Can't get device number for %s: %m", dev);
940 return -1;
941 }
942 if ((sbuf.st_mode & S_IFMT) != S_IFCHR) {
943 error("Can't lock %s: not a character device", dev);
944 return -1;
945 }
946 slprintf(lock_file, sizeof(lock_file), "%s/LK.%03d.%03d.%03d",
947 LOCK_DIR, major(sbuf.st_dev),
948 major(sbuf.st_rdev), minor(sbuf.st_rdev));
949 #else
950 char *p;
951 char lockdev[MAXPATHLEN];
952
953 if ((p = strstr(dev, "dev/")) != NULL) {
954 dev = p + 4;
955 strncpy(lockdev, dev, MAXPATHLEN-1);
956 lockdev[MAXPATHLEN-1] = 0;
957 while ((p = strrchr(lockdev, '/')) != NULL) {
958 *p = '_';
959 }
960 dev = lockdev;
961 } else
962 if ((p = strrchr(dev, '/')) != NULL)
963 dev = p + 1;
964
965 slprintf(lock_file, sizeof(lock_file), "%s/LCK..%s", LOCK_DIR, dev);
966 #endif
967
968 while ((fd = open(lock_file, O_EXCL | O_CREAT | O_RDWR, 0644)) < 0) {
969 if (errno != EEXIST) {
970 error("Can't create lock file %s: %m", lock_file);
971 break;
972 }
973
974 /* Read the lock file to find out who has the device locked. */
975 fd = open(lock_file, O_RDONLY, 0);
976 if (fd < 0) {
977 if (errno == ENOENT) /* This is just a timing problem. */
978 continue;
979 error("Can't open existing lock file %s: %m", lock_file);
980 break;
981 }
982 #ifndef LOCK_BINARY
983 n = read(fd, lock_buffer, 11);
984 #else
985 n = read(fd, &pid, sizeof(pid));
986 #endif /* LOCK_BINARY */
987 close(fd);
988 fd = -1;
989 if (n <= 0) {
990 error("Can't read pid from lock file %s", lock_file);
991 break;
992 }
993
994 /* See if the process still exists. */
995 #ifndef LOCK_BINARY
996 lock_buffer[n] = 0;
997 pid = atoi(lock_buffer);
998 #endif /* LOCK_BINARY */
999 if (pid == getpid())
1000 return 1; /* somebody else locked it for us */
1001 if (pid == 0
1002 || (kill(pid, 0) == -1 && errno == ESRCH)) {
1003 if (unlink (lock_file) == 0) {
1004 notice("Removed stale lock on %s (pid %d)", dev, pid);
1005 continue;
1006 }
1007 warn("Couldn't remove stale lock on %s", dev);
1008 } else
1009 notice("Device %s is locked by pid %d", dev, pid);
1010 break;
1011 }
1012
1013 if (fd < 0) {
1014 lock_file[0] = 0;
1015 return -1;
1016 }
1017
1018 pid = getpid();
1019 #ifndef LOCK_BINARY
1020 slprintf(lock_buffer, sizeof(lock_buffer), "%10d\n", pid);
1021 write (fd, lock_buffer, 11);
1022 #else
1023 write(fd, &pid, sizeof (pid));
1024 #endif
1025 close(fd);
1026 return 0;
1027
1028 #endif
1029 }
1030
1031 /*
1032 * relock - called to update our lockfile when we are about to detach,
1033 * thus changing our pid (we fork, the child carries on, and the parent dies).
1034 * Note that this is called by the parent, with pid equal to the pid
1035 * of the child. This avoids a potential race which would exist if
1036 * we had the child rewrite the lockfile (the parent might die first,
1037 * and another process could think the lock was stale if it checked
1038 * between when the parent died and the child rewrote the lockfile).
1039 */
1040 int
relock(pid)1041 relock(pid)
1042 int pid;
1043 {
1044 #ifdef LOCKLIB
1045 /* XXX is there a way to do this? */
1046 return -1;
1047 #else /* LOCKLIB */
1048
1049 int fd;
1050 char lock_buffer[12];
1051
1052 if (lock_file[0] == 0)
1053 return -1;
1054 fd = open(lock_file, O_WRONLY, 0);
1055 if (fd < 0) {
1056 error("Couldn't reopen lock file %s: %m", lock_file);
1057 lock_file[0] = 0;
1058 return -1;
1059 }
1060
1061 #ifndef LOCK_BINARY
1062 slprintf(lock_buffer, sizeof(lock_buffer), "%10d\n", pid);
1063 write (fd, lock_buffer, 11);
1064 #else
1065 write(fd, &pid, sizeof(pid));
1066 #endif /* LOCK_BINARY */
1067 close(fd);
1068 return 0;
1069
1070 #endif /* LOCKLIB */
1071 }
1072
1073 /*
1074 * unlock - remove our lockfile
1075 */
1076 void
unlock()1077 unlock()
1078 {
1079 if (lock_file[0]) {
1080 #ifdef LOCKLIB
1081 (void) rmlock(lock_file, (void *) 0);
1082 #else
1083 unlink(lock_file);
1084 #endif
1085 lock_file[0] = 0;
1086 }
1087 }
1088
1089