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