pppd/utils.c

   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, void (*) (void *, char *, ...),
  72                                void *));
  73
  74 struct buffer_info {
  75     char *ptr;
  76     int len;
  77 };
  78
  79 /*
  80  * strlcpy - like strcpy/strncpy, doesn't overflow destination buffer,
  81  * always leaves destination null-terminated (for len > 0).
  82  */
  83 size_t
  84 strlcpy(dest, src, len)
  85     char *dest;
  86     const char *src;
  87     size_t len;
  88 {
  89     size_t ret = strlen(src);
  90
  91     if (len != 0) {
  92         if (ret < len)
  93             strcpy(dest, src);
  94         else {
  95             strncpy(dest, src, len - 1);
  96             dest[len-1] = 0;
  97         }
  98     }
  99     return ret;
 100 }
 101
 102 /*
 103  * strlcat - like strcat/strncat, doesn't overflow destination buffer,
 104  * always leaves destination null-terminated (for len > 0).
 105  */
 106 size_t
 107 strlcat(dest, src, len)
 108     char *dest;
 109     const char *src;
 110     size_t len;
 111 {
 112     size_t dlen = strlen(dest);
 113
 114     return dlen + strlcpy(dest + dlen, src, (len > dlen? len - dlen: 0));
 115 }
 116
 117
 118 /*
 119  * slprintf - format a message into a buffer.  Like sprintf except we
 120  * also specify the length of the output buffer, and we handle
 121  * %m (error message), %v (visible string),
 122  * %q (quoted string), %t (current time) and %I (IP address) formats.
 123  * Doesn't do floating-point formats.
 124  * Returns the number of chars put into buf.
 125  */
 126 int
 127 slprintf __V((char *buf, int buflen, char *fmt, ...))
 128 {
 129     va_list args;
 130     int n;
 131
 132 #if defined(__STDC__)
 133     va_start(args, fmt);
 134 #else
 135     char *buf;
 136     int buflen;
 137     char *fmt;
 138     va_start(args);
 139     buf = va_arg(args, char *);
 140     buflen = va_arg(args, int);
 141     fmt = va_arg(args, char *);
 142 #endif
 143     n = vslprintf(buf, buflen, fmt, args);
 144     va_end(args);
 145     return n;
 146 }
 147
 148 /*
 149  * vslprintf - like slprintf, takes a va_list instead of a list of args.
 150  */
 151 #define OUTCHAR(c)      (buflen > 0? (--buflen, *buf++ = (c)): 0)
 152
 153 int
 154 vslprintf(buf, buflen, fmt, args)
 155     char *buf;
 156     int buflen;
 157     char *fmt;
 158     va_list args;
 159 {
 160     int c, i, n;
 161     int width, prec, fillch;
 162     int base, len, neg, quoted;
 163     unsigned long val = 0;
 164     char *str, *f, *buf0;
 165     unsigned char *p;
 166     char num[32];
 167     time_t t;
 168     u_int32_t ip;
 169     static char hexchars[] = "0123456789abcdef";
 170     struct buffer_info bufinfo;
 171
 172     buf0 = buf;
 173     --buflen;
 174     while (buflen > 0) {
 175         for (f = fmt; *f != '%' && *f != 0; ++f)
 176             ;
 177         if (f > fmt) {
 178             len = f - fmt;
 179             if (len > buflen)
 180                 len = buflen;
 181             memcpy(buf, fmt, len);
 182             buf += len;
 183             buflen -= len;
 184             fmt = f;
 185         }
 186         if (*fmt == 0)
 187             break;
 188         c = *++fmt;
 189         width = 0;
 190         prec = -1;
 191         fillch = ' ';
 192         if (c == '0') {
 193             fillch = '0';
 194             c = *++fmt;
 195         }
 196         if (c == '*') {
 197             width = va_arg(args, int);
 198             c = *++fmt;
 199         } else {
 200             while (isdigit(c)) {
 201                 width = width * 10 + c - '0';
 202                 c = *++fmt;
 203             }
 204         }
 205         if (c == '.') {
 206             c = *++fmt;
 207             if (c == '*') {
 208                 prec = va_arg(args, int);
 209                 c = *++fmt;
 210             } else {
 211                 prec = 0;
 212                 while (isdigit(c)) {
 213                     prec = prec * 10 + c - '0';
 214                     c = *++fmt;
 215                 }
 216             }
 217         }
 218         str = 0;
 219         base = 0;
 220         neg = 0;
 221         ++fmt;
 222         switch (c) {
 223         case 'l':
 224             c = *fmt++;
 225             switch (c) {
 226             case 'd':
 227                 val = va_arg(args, long);
 228                 if (val < 0) {
 229                     neg = 1;
 230                     val = -val;
 231                 }
 232                 base = 10;
 233                 break;
 234             case 'u':
 235                 val = va_arg(args, unsigned long);
 236                 base = 10;
 237                 break;
 238             default:
 239                 OUTCHAR('%');
 240                 OUTCHAR('l');
 241                 --fmt;          /* so %lz outputs %lz etc. */
 242                 continue;
 243             }
 244             break;
 245         case 'd':
 246             i = va_arg(args, int);
 247             if (i < 0) {
 248                 neg = 1;
 249                 val = -i;
 250             } else
 251                 val = i;
 252             base = 10;
 253             break;
 254         case 'u':
 255             val = va_arg(args, unsigned int);
 256             base = 10;
 257             break;
 258         case 'o':
 259             val = va_arg(args, unsigned int);
 260             base = 8;
 261             break;
 262         case 'x':
 263         case 'X':
 264             val = va_arg(args, unsigned int);
 265             base = 16;
 266             break;
 267         case 'p':
 268             val = (unsigned long) va_arg(args, void *);
 269             base = 16;
 270             neg = 2;
 271             break;
 272         case 's':
 273             str = va_arg(args, char *);
 274             break;
 275         case 'c':
 276             num[0] = va_arg(args, int);
 277             num[1] = 0;
 278             str = num;
 279             break;
 280         case 'm':
 281             str = strerror(errno);
 282             break;
 283         case 'I':
 284             ip = va_arg(args, u_int32_t);
 285             ip = ntohl(ip);
 286             slprintf(num, sizeof(num), "%d.%d.%d.%d", (ip >> 24) & 0xff,
 287                      (ip >> 16) & 0xff, (ip >> 8) & 0xff, ip & 0xff);
 288             str = num;
 289             break;
 290 #if 0   /* not used, and breaks on S/390, apparently */
 291         case 'r':
 292             f = va_arg(args, char *);
 293 #ifndef __powerpc__
 294             n = vslprintf(buf, buflen + 1, f, va_arg(args, va_list));
 295 #else
 296             /* On the powerpc, a va_list is an array of 1 structure */
 297             n = vslprintf(buf, buflen + 1, f, va_arg(args, void *));
 298 #endif
 299             buf += n;
 300             buflen -= n;
 301             continue;
 302 #endif
 303         case 't':
 304             time(&t);
 305             str = ctime(&t);
 306             str += 4;           /* chop off the day name */
 307             str[15] = 0;        /* chop off year and newline */
 308             break;
 309         case 'v':               /* "visible" string */
 310         case 'q':               /* quoted string */
 311             quoted = c == 'q';
 312             p = va_arg(args, unsigned char *);
 313             if (fillch == '0' && prec >= 0) {
 314                 n = prec;
 315             } else {
 316                 n = strlen((char *)p);
 317                 if (prec >= 0 && n > prec)
 318                     n = prec;
 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
 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
 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
 475 format_packet(p, len, printer, arg)
 476     u_char *p;
 477     int len;
 478     void (*printer) __P((void *, char *, ...));
 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
 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
 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
 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
 613 print_string(p, len, printer, arg)
 614     char *p;
 615     int len;
 616     void (*printer) __P((void *, char *, ...));
 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
 651 logit(level, fmt, args)
 652     int level;
 653     char *fmt;
 654     va_list args;
 655 {
 656     int n;
 657     char buf[1024];
 658
 659     n = vslprintf(buf, sizeof(buf), fmt, args);
 660     log_write(level, buf);
 661 }
 662
 663 static void
 664 log_write(level, buf)
 665     int level;
 666     char *buf;
 667 {
 668     syslog(level, "%s", buf);
 669     if (log_to_fd >= 0 && (level != LOG_DEBUG || debug)) {
 670         int n = strlen(buf);
 671
 672         if (n > 0 && buf[n-1] == '\n')
 673             --n;
 674         if (write(log_to_fd, buf, n) != n
 675             || write(log_to_fd, "\n", 1) != 1)
 676             log_to_fd = -1;
 677     }
 678 }
 679
 680 /*
 681  * fatal - log an error message and die horribly.
 682  */
 683 void
 684 fatal __V((char *fmt, ...))
 685 {
 686     va_list pvar;
 687
 688 #if defined(__STDC__)
 689     va_start(pvar, fmt);
 690 #else
 691     char *fmt;
 692     va_start(pvar);
 693     fmt = va_arg(pvar, char *);
 694 #endif
 695
 696     logit(LOG_ERR, fmt, pvar);
 697     va_end(pvar);
 698
 699     die(1);                     /* as promised */
 700 }
 701
 702 /*
 703  * error - log an error message.
 704  */
 705 void
 706 error __V((char *fmt, ...))
 707 {
 708     va_list pvar;
 709
 710 #if defined(__STDC__)
 711     va_start(pvar, fmt);
 712 #else
 713     char *fmt;
 714     va_start(pvar);
 715     fmt = va_arg(pvar, char *);
 716 #endif
 717
 718     logit(LOG_ERR, fmt, pvar);
 719     va_end(pvar);
 720     ++error_count;
 721 }
 722
 723 /*
 724  * warn - log a warning message.
 725  */
 726 void
 727 warn __V((char *fmt, ...))
 728 {
 729     va_list pvar;
 730
 731 #if defined(__STDC__)
 732     va_start(pvar, fmt);
 733 #else
 734     char *fmt;
 735     va_start(pvar);
 736     fmt = va_arg(pvar, char *);
 737 #endif
 738
 739     logit(LOG_WARNING, fmt, pvar);
 740     va_end(pvar);
 741 }
 742
 743 /*
 744  * notice - log a notice-level message.
 745  */
 746 void
 747 notice __V((char *fmt, ...))
 748 {
 749     va_list pvar;
 750
 751 #if defined(__STDC__)
 752     va_start(pvar, fmt);
 753 #else
 754     char *fmt;
 755     va_start(pvar);
 756     fmt = va_arg(pvar, char *);
 757 #endif
 758
 759     logit(LOG_NOTICE, fmt, pvar);
 760     va_end(pvar);
 761 }
 762
 763 /*
 764  * info - log an informational message.
 765  */
 766 void
 767 info __V((char *fmt, ...))
 768 {
 769     va_list pvar;
 770
 771 #if defined(__STDC__)
 772     va_start(pvar, fmt);
 773 #else
 774     char *fmt;
 775     va_start(pvar);
 776     fmt = va_arg(pvar, char *);
 777 #endif
 778
 779     logit(LOG_INFO, fmt, pvar);
 780     va_end(pvar);
 781 }
 782
 783 /*
 784  * dbglog - log a debug message.
 785  */
 786 void
 787 dbglog __V((char *fmt, ...))
 788 {
 789     va_list pvar;
 790
 791 #if defined(__STDC__)
 792     va_start(pvar, fmt);
 793 #else
 794     char *fmt;
 795     va_start(pvar);
 796     fmt = va_arg(pvar, char *);
 797 #endif
 798
 799     logit(LOG_DEBUG, fmt, pvar);
 800     va_end(pvar);
 801 }
 802
 803 /*
 804  * dump_packet - print out a packet in readable form if it is interesting.
 805  * Assumes len >= PPP_HDRLEN.
 806  */
 807 void
 808 dump_packet(const char *tag, unsigned char *p, int len)
 809 {
 810     int proto;
 811
 812     if (!debug)
 813         return;
 814
 815     /*
 816      * don't print LCP echo request/reply packets if debug <= 1
 817      * and the link is up.
 818      */
 819     proto = (p[2] << 8) + p[3];
 820     if (debug <= 1 && unsuccess == 0 && proto == PPP_LCP
 821         && len >= PPP_HDRLEN + HEADERLEN) {
 822         unsigned char *lcp = p + PPP_HDRLEN;
 823         int l = (lcp[2] << 8) + lcp[3];
 824
 825         if ((lcp[0] == ECHOREQ || lcp[0] == ECHOREP)
 826             && l >= HEADERLEN && l <= len - PPP_HDRLEN)
 827             return;
 828     }
 829
 830     dbglog("%s %P", tag, p, len);
 831 }
 832
 833 /*
 834  * complete_read - read a full `count' bytes from fd,
 835  * unless end-of-file or an error other than EINTR is encountered.
 836  */
 837 ssize_t
 838 complete_read(int fd, void *buf, size_t count)
 839 {
 840         size_t done;
 841         ssize_t nb;
 842         char *ptr = buf;
 843
 844         for (done = 0; done < count; ) {
 845                 nb = read(fd, ptr, count - done);
 846                 if (nb < 0) {
 847                         if (errno == EINTR)
 848                                 continue;
 849                         return -1;
 850                 }
 851                 if (nb == 0)
 852                         break;
 853                 done += nb;
 854                 ptr += nb;
 855         }
 856         return done;
 857 }
 858
 859 /* Procedures for locking the serial device using a lock file. */
 860 #ifndef LOCK_DIR
 861 #ifdef __linux__
 862 #define LOCK_DIR        "/var/lock"
 863 #else
 864 #ifdef SVR4
 865 #define LOCK_DIR        "/var/spool/locks"
 866 #else
 867 #define LOCK_DIR        "/var/spool/lock"
 868 #endif
 869 #endif
 870 #endif /* LOCK_DIR */
 871
 872 static char lock_file[MAXPATHLEN];
 873
 874 /*
 875  * lock - create a lock file for the named device
 876  */
 877 int
 878 lock(dev)
 879     char *dev;
 880 {
 881 #ifdef LOCKLIB
 882     int result;
 883
 884     result = mklock (dev, (void *) 0);
 885     if (result == 0) {
 886         strlcpy(lock_file, dev, sizeof(lock_file));
 887         return 0;
 888     }
 889
 890     if (result > 0)
 891         notice("Device %s is locked by pid %d", dev, result);
 892     else
 893         error("Can't create lock file %s", lock_file);
 894     return -1;
 895
 896 #else /* LOCKLIB */
 897
 898     char lock_buffer[12];
 899     int fd, pid, n;
 900
 901 #ifdef SVR4
 902     struct stat sbuf;
 903
 904     if (stat(dev, &sbuf) < 0) {
 905         error("Can't get device number for %s: %m", dev);
 906         return -1;
 907     }
 908     if ((sbuf.st_mode & S_IFMT) != S_IFCHR) {
 909         error("Can't lock %s: not a character device", dev);
 910         return -1;
 911     }
 912     slprintf(lock_file, sizeof(lock_file), "%s/LK.%03d.%03d.%03d",
 913              LOCK_DIR, major(sbuf.st_dev),
 914              major(sbuf.st_rdev), minor(sbuf.st_rdev));
 915 #else
 916     char *p;
 917     char lockdev[MAXPATHLEN];
 918
 919     if ((p = strstr(dev, "dev/")) != NULL) {
 920         dev = p + 4;
 921         strncpy(lockdev, dev, MAXPATHLEN-1);
 922         lockdev[MAXPATHLEN-1] = 0;
 923         while ((p = strrchr(lockdev, '/')) != NULL) {
 924             *p = '_';
 925         }
 926         dev = lockdev;
 927     } else
 928         if ((p = strrchr(dev, '/')) != NULL)
 929             dev = p + 1;
 930
 931     slprintf(lock_file, sizeof(lock_file), "%s/LCK..%s", LOCK_DIR, dev);
 932 #endif
 933
 934     while ((fd = open(lock_file, O_EXCL | O_CREAT | O_RDWR, 0644)) < 0) {
 935         if (errno != EEXIST) {
 936             error("Can't create lock file %s: %m", lock_file);
 937             break;
 938         }
 939
 940         /* Read the lock file to find out who has the device locked. */
 941         fd = open(lock_file, O_RDONLY, 0);
 942         if (fd < 0) {
 943             if (errno == ENOENT) /* This is just a timing problem. */
 944                 continue;
 945             error("Can't open existing lock file %s: %m", lock_file);
 946             break;
 947         }
 948 #ifndef LOCK_BINARY
 949         n = read(fd, lock_buffer, 11);
 950 #else
 951         n = read(fd, &pid, sizeof(pid));
 952 #endif /* LOCK_BINARY */
 953         close(fd);
 954         fd = -1;
 955         if (n <= 0) {
 956             error("Can't read pid from lock file %s", lock_file);
 957             break;
 958         }
 959
 960         /* See if the process still exists. */
 961 #ifndef LOCK_BINARY
 962         lock_buffer[n] = 0;
 963         pid = atoi(lock_buffer);
 964 #endif /* LOCK_BINARY */
 965         if (pid == getpid())
 966             return 1;           /* somebody else locked it for us */
 967         if (pid == 0
 968             || (kill(pid, 0) == -1 && errno == ESRCH)) {
 969             if (unlink (lock_file) == 0) {
 970                 notice("Removed stale lock on %s (pid %d)", dev, pid);
 971                 continue;
 972             }
 973             warn("Couldn't remove stale lock on %s", dev);
 974         } else
 975             notice("Device %s is locked by pid %d", dev, pid);
 976         break;
 977     }
 978
 979     if (fd < 0) {
 980         lock_file[0] = 0;
 981         return -1;
 982     }
 983
 984     pid = getpid();
 985 #ifndef LOCK_BINARY
 986     slprintf(lock_buffer, sizeof(lock_buffer), "%10d\n", pid);
 987     write (fd, lock_buffer, 11);
 988 #else
 989     write(fd, &pid, sizeof (pid));
 990 #endif
 991     close(fd);
 992     return 0;
 993
 994 #endif
 995 }
 996
 997 /*
 998  * relock - called to update our lockfile when we are about to detach,
 999  * thus changing our pid (we fork, the child carries on, and the parent dies).
1000  * Note that this is called by the parent, with pid equal to the pid
1001  * of the child.  This avoids a potential race which would exist if
1002  * we had the child rewrite the lockfile (the parent might die first,
1003  * and another process could think the lock was stale if it checked
1004  * between when the parent died and the child rewrote the lockfile).
1005  */
1006 int
1007 relock(pid)
1008     int pid;
1009 {
1010 #ifdef LOCKLIB
1011     /* XXX is there a way to do this? */
1012     return -1;
1013 #else /* LOCKLIB */
1014
1015     int fd;
1016     char lock_buffer[12];
1017
1018     if (lock_file[0] == 0)
1019         return -1;
1020     fd = open(lock_file, O_WRONLY, 0);
1021     if (fd < 0) {
1022         error("Couldn't reopen lock file %s: %m", lock_file);
1023         lock_file[0] = 0;
1024         return -1;
1025     }
1026
1027 #ifndef LOCK_BINARY
1028     slprintf(lock_buffer, sizeof(lock_buffer), "%10d\n", pid);
1029     write (fd, lock_buffer, 11);
1030 #else
1031     write(fd, &pid, sizeof(pid));
1032 #endif /* LOCK_BINARY */
1033     close(fd);
1034     return 0;
1035
1036 #endif /* LOCKLIB */
1037 }
1038
1039 /*
1040  * unlock - remove our lockfile
1041  */
1042 void
1043 unlock()
1044 {
1045     if (lock_file[0]) {
1046 #ifdef LOCKLIB
1047         (void) rmlock(lock_file, (void *) 0);
1048 #else
1049         unlink(lock_file);
1050 #endif
1051         lock_file[0] = 0;
1052     }
1053 }
1054