diplodocus.org Git - nmh/blob - sbr/mf.c

   1
   2 /*
   3  * mf.c -- mail filter subroutines
   4  *
   5  * $Id$
   6  *
   7  * This code is Copyright (c) 2002, by the authors of nmh.  See the
   8  * COPYRIGHT file in the root directory of the nmh distribution for
   9  * complete copyright information.
  10  */
  11
  12 #include <h/mf.h>
  13 #include <ctype.h>
  14 #include <stdio.h>
  15
  16 /*
  17  * static prototypes
  18  */
  19 static char *getcpy (char *);
  20 static char *add (char *, char *);
  21 static void compress (char *, char *);
  22 static int isat (char *);
  23 static int parse_address (void);
  24 static int phrase (char *);
  25 static int route_addr (char *);
  26 static int local_part (char *);
  27 static int domain (char *);
  28 static int route (char *);
  29 static int my_lex (char *);
  30
  31
  32 static char *
  33 getcpy (char *s)
  34 {
  35     register char *p;
  36
  37     if (!s) {
  38 /* causes compiles to blow up because the symbol _cleanup is undefined
  39    where did this ever come from? */
  40         /* _cleanup(); */
  41         abort();
  42         for(;;)
  43             pause();
  44     }
  45     if ((p = malloc ((size_t) (strlen (s) + 2))))
  46         strcpy (p, s);
  47     return p;
  48 }
  49
  50
  51 static char *
  52 add (char *s1, char *s2)
  53 {
  54     register char *p;
  55
  56     if (!s2)
  57         return getcpy (s1);
  58
  59     if ((p = malloc ((size_t) (strlen (s1) + strlen (s2) + 2))))
  60         sprintf (p, "%s%s", s2, s1);
  61     free (s2);
  62     return p;
  63 }
  64
  65 int
  66 isfrom(char *string)
  67 {
  68     return (strncmp (string, "From ", 5) == 0
  69             || strncmp (string, ">From ", 6) == 0);
  70 }
  71
  72
  73 int
  74 lequal (char *a, char *b)
  75 {
  76     for (; *a; a++, b++)
  77         if (*b == 0)
  78             return FALSE;
  79         else {
  80             char c1 = islower (*a) ? toupper (*a) : *a;
  81             char c2 = islower (*b) ? toupper (*b) : *b;
  82             if (c1 != c2)
  83                 return FALSE;
  84         }
  85
  86     return (*b == 0);
  87 }
  88
  89
  90 /*
  91  * seekadrx() is tricky.  We want to cover both UUCP-style and ARPA-style
  92  * addresses, so for each list of addresses we see if we can find some
  93  * character to give us a hint.
  94  */
  95
  96
  97 #define CHKADR  0               /* undertermined address style */
  98 #define UNIXDR  1               /* UNIX-style address */
  99 #define ARPADR  2               /* ARPAnet-style address */
 100
 101
 102 static char *punctuators = ";<>.()[]";
 103 static char *vp = NULL;
 104 static char *tp = NULL;
 105
 106 static struct adrx adrxs1;
 107
 108
 109 struct adrx *
 110 seekadrx (char *addrs)
 111 {
 112     static int state = CHKADR;
 113     register char *cp;
 114     register struct adrx *adrxp;
 115
 116     if (state == CHKADR)
 117         for (state = UNIXDR, cp = addrs; *cp; cp++)
 118             if (strchr(punctuators, *cp)) {
 119                 state = ARPADR;
 120                 break;
 121             }
 122
 123     switch (state) {
 124         case UNIXDR:
 125             adrxp = uucpadrx (addrs);
 126             break;
 127
 128         case ARPADR:
 129         default:
 130             adrxp = getadrx (addrs);
 131             break;
 132     }
 133
 134     if (adrxp == NULL)
 135         state = CHKADR;
 136
 137     return adrxp;
 138 }
 139
 140
 141 /*
 142  * uucpadrx() implements a partial UUCP-style address parser.  It's based
 143  * on the UUCP notion that addresses are separated by spaces or commas.
 144  */
 145
 146
 147 struct adrx *
 148 uucpadrx (char *addrs)
 149 {
 150     register char *cp, *wp, *xp, *yp, *zp;
 151     register struct adrx *adrxp = &adrxs1;
 152
 153     if (vp == NULL) {
 154         vp = tp = getcpy (addrs);
 155         compress (addrs, vp);
 156     }
 157     else
 158         if (tp == NULL) {
 159             free (vp);
 160             vp = NULL;
 161             return NULL;
 162         }
 163
 164     for (cp = tp; isspace (*cp); cp++)
 165         continue;
 166     if (*cp == 0) {
 167         free (vp);
 168         vp = tp = NULL;
 169         return NULL;
 170     }
 171
 172     if ((wp = strchr(cp, ',')) == NULL) {
 173         if ((wp = strchr(cp, ' ')) != NULL) {
 174             xp = wp;
 175             while (isspace (*xp))
 176                 xp++;
 177             if (*xp != 0 && isat (--xp)) {
 178                 yp = xp + 4;
 179                 while (isspace (*yp))
 180                     yp++;
 181                 if (*yp != 0) {
 182                     if ((zp = strchr(yp, ' ')) != NULL)
 183                         *zp = 0, tp = ++zp;
 184                     else
 185                         tp = NULL;
 186                 }
 187                 else
 188                     *wp = 0, tp = ++wp;
 189             }
 190             else
 191                 *wp = 0, tp = ++wp;
 192         }
 193         else
 194             tp = NULL;
 195     }
 196     else
 197         *wp = 0, tp = ++wp;
 198
 199     if (adrxp->text)
 200         free (adrxp->text);
 201     adrxp->text = getcpy (cp);
 202     adrxp->mbox = cp;
 203     adrxp->host = adrxp->path = NULL;
 204     if ((wp = strrchr(cp, '@')) != NULL) {
 205         *wp++ = 0;
 206         adrxp->host = *wp ? wp : NULL;
 207     }
 208     else
 209         for (wp = cp + strlen (cp) - 4; wp >= cp; wp--)
 210             if (isat (wp)) {
 211                 *wp++ = 0;
 212                 adrxp->host = wp + 3;
 213             }
 214
 215     adrxp->pers = adrxp->grp = adrxp->note = adrxp->err = NULL;
 216     adrxp->ingrp = 0;
 217
 218     return adrxp;
 219 }
 220
 221
 222 static void
 223 compress (char *fp, char *tp)
 224 {
 225     register char c, *cp;
 226
 227     for (c = ' ', cp = tp; (*tp = *fp++) != 0;)
 228         if (isspace (*tp)) {
 229             if (c != ' ')
 230                 *tp++ = c = ' ';
 231         }
 232         else
 233             c = *tp++;
 234
 235     if (c == ' ' && cp < tp)
 236         *--tp = 0;
 237 }
 238
 239
 240 static int
 241 isat (char *p)
 242 {
 243     return (strncmp (p, " AT ", 4)
 244             && strncmp (p, " At ", 4)
 245             && strncmp (p, " aT ", 4)
 246             && strncmp (p, " at ", 4) ? FALSE : TRUE);
 247 }
 248
 249
 250 /*
 251  *
 252  * getadrx() implements a partial 822-style address parser.  The parser
 253  * is neither complete nor correct.  It does however recognize nearly all
 254  * of the 822 address syntax.  In addition it handles the majority of the
 255  * 733 syntax as well.  Most problems arise from trying to accomodate both.
 256  *
 257  * In terms of 822, the route-specification in
 258  *
 259  *               "<" [route] local-part "@" domain ">"
 260  *
 261  * is parsed and returned unchanged.  Multiple at-signs are compressed
 262  * via source-routing.  Recursive groups are not allowed as per the
 263  * standard.
 264  *
 265  * In terms of 733, " at " is recognized as equivalent to "@".
 266  *
 267  * In terms of both the parser will not complain about missing hosts.
 268  *
 269  * -----
 270  *
 271  * We should not allow addresses like
 272  *
 273  *              Marshall T. Rose <MRose@UCI>
 274  *
 275  * but should insist on
 276  *
 277  *              "Marshall T. Rose" <MRose@UCI>
 278  *
 279  * Unfortunately, a lot of mailers stupidly let people get away with this.
 280  *
 281  * -----
 282  *
 283  * We should not allow addresses like
 284  *
 285  *              <MRose@UCI>
 286  *
 287  * but should insist on
 288  *
 289  *              MRose@UCI
 290  *
 291  * Unfortunately, a lot of mailers stupidly let people's UAs get away with
 292  * this.
 293  *
 294  * -----
 295  *
 296  * We should not allow addresses like
 297  *
 298  *              @UCI:MRose@UCI-750a
 299  *
 300  * but should insist on
 301  *
 302  *              Marshall Rose <@UCI:MRose@UCI-750a>
 303  *
 304  * Unfortunately, a lot of mailers stupidly do this.
 305  *
 306  */
 307
 308 #define QUOTE   '\\'
 309
 310 #define LX_END   0
 311 #define LX_ERR   1
 312 #define LX_ATOM  2
 313 #define LX_QSTR  3
 314 #define LX_DLIT  4
 315 #define LX_SEMI  5
 316 #define LX_COMA  6
 317 #define LX_LBRK  7
 318 #define LX_RBRK  8
 319 #define LX_COLN  9
 320 #define LX_DOT  10
 321 #define LX_AT   11
 322
 323 struct specials {
 324     char lx_chr;
 325     int  lx_val;
 326 };
 327
 328 static struct specials special[] = {
 329     { ';',   LX_SEMI },
 330     { ',',   LX_COMA },
 331     { '<',   LX_LBRK },
 332     { '>',   LX_RBRK },
 333     { ':',   LX_COLN },
 334     { '.',   LX_DOT },
 335     { '@',   LX_AT },
 336     { '(',   LX_ERR },
 337     { ')',   LX_ERR },
 338     { QUOTE, LX_ERR },
 339     { '"',   LX_ERR },
 340     { '[',   LX_ERR },
 341     { ']',   LX_ERR },
 342     { 0,     0 }
 343 };
 344
 345 static int glevel = 0;
 346 static int ingrp = 0;
 347 static int last_lex = LX_END;
 348
 349 static char *dp = NULL;
 350 static char *cp = NULL;
 351 static char *ap = NULL;
 352 static char *pers = NULL;
 353 static char *mbox = NULL;
 354 static char *host = NULL;
 355 static char *path = NULL;
 356 static char *grp = NULL;
 357 static char *note = NULL;
 358 static char err[BUFSIZ];
 359 static char adr[BUFSIZ];
 360
 361 static struct adrx  adrxs2;
 362
 363
 364 struct adrx *
 365 getadrx (char *addrs)
 366 {
 367     register char *bp;
 368     register struct adrx *adrxp = &adrxs2;
 369
 370     if (pers)
 371         free (pers);
 372     if (mbox)
 373         free (mbox);
 374     if (host)
 375         free (host);
 376     if (path)
 377         free (path);
 378     if (grp)
 379         free (grp);
 380     if (note)
 381         free (note);
 382     pers = mbox = host = path = grp = note = NULL;
 383     err[0] = 0;
 384
 385     if (dp == NULL) {
 386         dp = cp = getcpy (addrs ? addrs : "");
 387         glevel = 0;
 388     }
 389     else
 390         if (cp == NULL) {
 391             free (dp);
 392             dp = NULL;
 393             return NULL;
 394         }
 395
 396     switch (parse_address ()) {
 397         case DONE:
 398             free (dp);
 399             dp = cp = NULL;
 400             return NULL;
 401
 402         case OK:
 403             switch (last_lex) {
 404                 case LX_COMA:
 405                 case LX_END:
 406                     break;
 407
 408                 default:        /* catch trailing comments */
 409                     bp = cp;
 410                     my_lex (adr);
 411                     cp = bp;
 412                     break;
 413             }
 414             break;
 415
 416         default:
 417             break;
 418         }
 419
 420     if (err[0])
 421         for (;;) {
 422             switch (last_lex) {
 423                 case LX_COMA:
 424                 case LX_END:
 425                     break;
 426
 427                 default:
 428                     my_lex (adr);
 429                     continue;
 430             }
 431             break;
 432         }
 433     while (isspace (*ap))
 434         ap++;
 435     if (cp)
 436         sprintf (adr, "%.*s", cp - ap, ap);
 437     else
 438         strcpy (adr, ap);
 439     bp = adr + strlen (adr) - 1;
 440     if (*bp == ',' || *bp == ';' || *bp == '\n')
 441         *bp = 0;
 442
 443     adrxp->text = adr;
 444     adrxp->pers = pers;
 445     adrxp->mbox = mbox;
 446     adrxp->host = host;
 447     adrxp->path = path;
 448     adrxp->grp = grp;
 449     adrxp->ingrp = ingrp;
 450     adrxp->note = note;
 451     adrxp->err = err[0] ? err : NULL;
 452
 453     return adrxp;
 454 }
 455
 456
 457 static int
 458 parse_address (void)
 459 {
 460     char buffer[BUFSIZ];
 461
 462 again: ;
 463     ap = cp;
 464     switch (my_lex (buffer)) {
 465         case LX_ATOM:
 466         case LX_QSTR:
 467             pers = getcpy (buffer);
 468             break;
 469
 470         case LX_SEMI:
 471             if (glevel-- <= 0) {
 472                 strcpy (err, "extraneous semi-colon");
 473                 return NOTOK;
 474             }
 475         case LX_COMA:
 476             if (note) {
 477                 free (note);
 478                 note = NULL;
 479             }
 480             goto again;
 481
 482         case LX_END:
 483             return DONE;
 484
 485         case LX_LBRK:           /* sigh (2) */
 486             goto get_addr;
 487
 488         case LX_AT:             /* sigh (3) */
 489             cp = ap;
 490             if (route_addr (buffer) == NOTOK)
 491                 return NOTOK;
 492             return OK;          /* why be choosy? */
 493
 494         default:
 495             sprintf (err, "illegal address construct (%s)", buffer);
 496             return NOTOK;
 497     }
 498
 499     switch (my_lex (buffer)) {
 500         case LX_ATOM:
 501         case LX_QSTR:
 502             pers = add (buffer, add (" ", pers));
 503     more_phrase: ;              /* sigh (1) */
 504             if (phrase (buffer) == NOTOK)
 505                 return NOTOK;
 506
 507             switch (last_lex) {
 508                 case LX_LBRK:
 509             get_addr: ;
 510                     if (route_addr (buffer) == NOTOK)
 511                         return NOTOK;
 512                     if (last_lex == LX_RBRK)
 513                         return OK;
 514                     sprintf (err, "missing right-bracket (%s)", buffer);
 515                     return NOTOK;
 516
 517                 case LX_COLN:
 518             get_group: ;
 519                     if (glevel++ > 0) {
 520                         sprintf (err, "nested groups not allowed (%s)", pers);
 521                         return NOTOK;
 522                     }
 523                     grp = add (": ", pers);
 524                     pers = NULL;
 525                     {
 526                         char   *pp = cp;
 527
 528                         for (;;)
 529                             switch (my_lex (buffer)) {
 530                                 case LX_SEMI:
 531                                 case LX_END: /* tsk, tsk */
 532                                     glevel--;
 533                                     return OK;
 534
 535                                 case LX_COMA:
 536                                     continue;
 537
 538                                 default:
 539                                     cp = pp;
 540                                     return parse_address ();
 541                             }
 542                     }
 543
 544                 case LX_DOT:    /* sigh (1) */
 545                     pers = add (".", pers);
 546                     goto more_phrase;
 547
 548                 default:
 549                     sprintf (err, "no mailbox in address, only a phrase (%s%s)",
 550                             pers, buffer);
 551                     return NOTOK;
 552             }
 553
 554         case LX_LBRK:
 555             goto get_addr;
 556
 557         case LX_COLN:
 558             goto get_group;
 559
 560         case LX_DOT:
 561             mbox = add (buffer, pers);
 562             pers = NULL;
 563             if (route_addr (buffer) == NOTOK)
 564                 return NOTOK;
 565             goto check_end;
 566
 567         case LX_AT:
 568             ingrp = glevel;
 569             mbox = pers;
 570             pers = NULL;
 571             if (domain (buffer) == NOTOK)
 572                 return NOTOK;
 573     check_end: ;
 574             switch (last_lex) {
 575                 case LX_SEMI:
 576                     if (glevel-- <= 0) {
 577                         strcpy (err, "extraneous semi-colon");
 578                         return NOTOK;
 579                     }
 580                 case LX_COMA:
 581                 case LX_END:
 582                     return OK;
 583
 584                 default:
 585                     sprintf (err, "junk after local@domain (%s)", buffer);
 586                     return NOTOK;
 587             }
 588
 589         case LX_SEMI:           /* no host */
 590         case LX_COMA:
 591         case LX_END:
 592             ingrp = glevel;
 593             if (last_lex == LX_SEMI && glevel-- <= 0) {
 594                 strcpy (err, "extraneous semi-colon");
 595                 return NOTOK;
 596             }
 597             mbox = pers;
 598             pers = NULL;
 599             return OK;
 600
 601         default:
 602             sprintf (err, "missing mailbox (%s)", buffer);
 603             return NOTOK;
 604     }
 605 }
 606
 607
 608 static int
 609 phrase (char *buffer)
 610 {
 611     for (;;)
 612         switch (my_lex (buffer)) {
 613             case LX_ATOM:
 614             case LX_QSTR:
 615                 pers = add (buffer, add (" ", pers));
 616                 continue;
 617
 618             default:
 619                 return OK;
 620         }
 621 }
 622
 623
 624 static int
 625 route_addr (char *buffer)
 626 {
 627     register char *pp = cp;
 628
 629     if (my_lex (buffer) == LX_AT) {
 630         if (route (buffer) == NOTOK)
 631             return NOTOK;
 632     }
 633     else
 634         cp = pp;
 635
 636     if (local_part (buffer) == NOTOK)
 637         return NOTOK;
 638
 639     switch (last_lex) {
 640         case LX_AT:
 641             return domain (buffer);
 642
 643         case LX_SEMI:   /* if in group */
 644         case LX_RBRK:           /* no host */
 645         case LX_COMA:
 646         case LX_END:
 647             return OK;
 648
 649         default:
 650             sprintf (err, "no at-sign after local-part (%s)", buffer);
 651             return NOTOK;
 652     }
 653 }
 654
 655
 656 static int
 657 local_part (char *buffer)
 658 {
 659     ingrp = glevel;
 660
 661     for (;;) {
 662         switch (my_lex (buffer)) {
 663             case LX_ATOM:
 664             case LX_QSTR:
 665                 mbox = add (buffer, mbox);
 666                 break;
 667
 668             default:
 669                 sprintf (err, "no mailbox in local-part (%s)", buffer);
 670                 return NOTOK;
 671         }
 672
 673         switch (my_lex (buffer)) {
 674             case LX_DOT:
 675                 mbox = add (buffer, mbox);
 676                 continue;
 677
 678             default:
 679                 return OK;
 680         }
 681     }
 682 }
 683
 684
 685 static int
 686 domain (char *buffer)
 687 {
 688     for (;;) {
 689         switch (my_lex (buffer)) {
 690             case LX_ATOM:
 691             case LX_DLIT:
 692                 host = add (buffer, host);
 693                 break;
 694
 695             default:
 696                 sprintf (err, "no sub-domain in domain-part of address (%s)", buffer);
 697                 return NOTOK;
 698         }
 699
 700         switch (my_lex (buffer)) {
 701             case LX_DOT:
 702                 host = add (buffer, host);
 703                 continue;
 704
 705             case LX_AT:         /* sigh (0) */
 706                 mbox = add (host, add ("%", mbox));
 707                 free (host);
 708                 host = NULL;
 709                 continue;
 710
 711             default:
 712                 return OK;
 713         }
 714     }
 715 }
 716
 717
 718 static int
 719 route (char *buffer)
 720 {
 721     path = getcpy ("@");
 722
 723     for (;;) {
 724         switch (my_lex (buffer)) {
 725             case LX_ATOM:
 726             case LX_DLIT:
 727                 path = add (buffer, path);
 728                 break;
 729
 730             default:
 731                 sprintf (err, "no sub-domain in domain-part of address (%s)", buffer);
 732                 return NOTOK;
 733         }
 734         switch (my_lex (buffer)) {
 735             case LX_COMA:
 736                 path = add (buffer, path);
 737                 for (;;) {
 738                     switch (my_lex (buffer)) {
 739                         case LX_COMA:
 740                             continue;
 741
 742                         case LX_AT:
 743                             path = add (buffer, path);
 744                             break;
 745
 746                         default:
 747                             sprintf (err, "no at-sign found for next domain in route (%s)",
 748                                      buffer);
 749                     }
 750                     break;
 751                 }
 752                 continue;
 753
 754             case LX_AT:         /* XXX */
 755             case LX_DOT:
 756                 path = add (buffer, path);
 757                 continue;
 758
 759             case LX_COLN:
 760                 path = add (buffer, path);
 761                 return OK;
 762
 763             default:
 764                 sprintf (err, "no colon found to terminate route (%s)", buffer);
 765                 return NOTOK;
 766         }
 767     }
 768 }
 769
 770
 771 static int
 772 my_lex (char *buffer)
 773 {
 774     int i, gotat = 0;
 775     register char c, *bp;
 776
 777     bp = buffer;
 778     *bp = 0;
 779     if (!cp)
 780         return (last_lex = LX_END);
 781
 782     gotat = isat (cp);
 783     c = *cp++;
 784     while (isspace (c))
 785         c = *cp++;
 786     if (c == 0) {
 787         cp = NULL;
 788         return (last_lex = LX_END);
 789     }
 790
 791     if (c == '(')
 792         for (*bp++ = c, i = 0;;)
 793             switch (c = *cp++) {
 794                 case 0:
 795                     cp = NULL;
 796                     return (last_lex = LX_ERR);
 797                 case QUOTE:
 798                     *bp++ = c;
 799                     if ((c = *cp++) == 0) {
 800                         cp = NULL;
 801                         return (last_lex = LX_ERR);
 802                     }
 803                     *bp++ = c;
 804                     continue;
 805                 case '(':
 806                     i++;
 807                 default:
 808                     *bp++ = c;
 809                     continue;
 810                 case ')':
 811                     *bp++ = c;
 812                     if (--i < 0) {
 813                         *bp = 0;
 814                         note = note ? add (buffer, add (" ", note))
 815                             : getcpy (buffer);
 816                         return my_lex (buffer);
 817                     }
 818             }
 819
 820     if (c == '"')
 821         for (*bp++ = c;;)
 822             switch (c = *cp++) {
 823                 case 0:
 824                     cp = NULL;
 825                     return (last_lex = LX_ERR);
 826                 case QUOTE:
 827                     *bp++ = c;
 828                     if ((c = *cp++) == 0) {
 829                         cp = NULL;
 830                         return (last_lex = LX_ERR);
 831                     }
 832                 default:
 833                     *bp++ = c;
 834                     continue;
 835                 case '"':
 836                     *bp++ = c;
 837                     *bp = 0;
 838                     return (last_lex = LX_QSTR);
 839             }
 840
 841     if (c == '[')
 842         for (*bp++ = c;;)
 843             switch (c = *cp++) {
 844                 case 0:
 845                     cp = NULL;
 846                     return (last_lex = LX_ERR);
 847                 case QUOTE:
 848                     *bp++ = c;
 849                     if ((c = *cp++) == 0) {
 850                         cp = NULL;
 851                         return (last_lex = LX_ERR);
 852                     }
 853                 default:
 854                     *bp++ = c;
 855                     continue;
 856                 case ']':
 857                     *bp++ = c;
 858                     *bp = 0;
 859                     return (last_lex = LX_DLIT);
 860             }
 861
 862     *bp++ = c;
 863     *bp = 0;
 864     for (i = 0; special[i].lx_chr != 0; i++)
 865         if (c == special[i].lx_chr)
 866             return (last_lex = special[i].lx_val);
 867
 868     if (iscntrl (c))
 869         return (last_lex = LX_ERR);
 870
 871     for (;;) {
 872         if ((c = *cp++) == 0)
 873             break;
 874         for (i = 0; special[i].lx_chr != 0; i++)
 875             if (c == special[i].lx_chr)
 876                 goto got_atom;
 877         if (iscntrl (c) || isspace (c))
 878             break;
 879         *bp++ = c;
 880     }
 881 got_atom: ;
 882     if (c == 0)
 883         cp = NULL;
 884     else
 885         cp--;
 886     *bp = 0;
 887     last_lex = !gotat || cp == NULL || strchr(cp, '<') != NULL
 888         ? LX_ATOM : LX_AT;
 889     return last_lex;
 890 }
 891
 892
 893 char *
 894 legal_person (char *p)
 895 {
 896     int i;
 897     register char *cp;
 898     static char buffer[BUFSIZ];
 899
 900     if (*p == '"')
 901         return p;
 902     for (cp = p; *cp; cp++)
 903         for (i = 0; special[i].lx_chr; i++)
 904             if (*cp == special[i].lx_chr) {
 905                 sprintf (buffer, "\"%s\"", p);
 906                 return buffer;
 907             }
 908
 909     return p;
 910 }
 911
 912
 913 int
 914 mfgets (FILE *in, char **bp)
 915 {
 916     int i;
 917     register char *cp, *dp, *ep;
 918     static int len = 0;
 919     static char *pp = NULL;
 920
 921     if (pp == NULL)
 922         if (!(pp = malloc ((size_t) (len = BUFSIZ))))
 923             return NOTOK;
 924
 925     for (ep = (cp = pp) + len - 2;;) {
 926         switch (i = getc (in)) {
 927             case EOF:
 928         eol:    ;
 929                 if (cp != pp) {
 930                     *cp = 0;
 931                     *bp = pp;
 932                     return OK;
 933                 }
 934         eoh:    ;
 935                 *bp = NULL;
 936                 free (pp);
 937                 pp = NULL;
 938                 return DONE;
 939
 940             case 0:
 941                 continue;
 942
 943             case '\n':
 944                 if (cp == pp)   /* end of headers, gobble it */
 945                     goto eoh;
 946                 switch (i = getc (in)) {
 947                     default:    /* end of line */
 948                     case '\n':  /* end of headers, save for next call */
 949                         ungetc (i, in);
 950                         goto eol;
 951
 952                     case ' ':   /* continue headers */
 953                     case '\t':
 954                         *cp++ = '\n';
 955                         break;
 956                 }               /* fall into default case */
 957
 958             default:
 959                 *cp++ = i;
 960                 break;
 961         }
 962         if (cp >= ep) {
 963             if (!(dp = realloc (pp, (size_t) (len += BUFSIZ)))) {
 964                 free (pp);
 965                 pp = NULL;
 966                 return NOTOK;
 967             }
 968             else
 969                 cp += dp - pp, ep = (pp = cp) + len - 2;
 970         }
 971     }
 972 }