ircd/crule.c

   1 /**
   2  * @file
   3  * @brief Connection rule parser and checker
   4  * @version $Id: crule.c,v 1.9 2005/03/20 16:06:17 entrope Exp $
   5  *
   6  * by Tony Vencill (Tonto on IRC) <vencill@bga.com>
   7  *
   8  * The majority of this file is a recursive descent parser used to convert
   9  * connection rules into expression trees when the conf file is read.
  10  * All parsing structures and types are hidden in the interest of good
  11  * programming style and to make possible future data structure changes
  12  * without affecting the interface between this patch and the rest of the
  13  * server.  The only functions accessible externally are crule_parse,
  14  * crule_free, and crule_eval.  Prototypes for these functions can be
  15  * found in h.h.
  16  *
  17  * Please direct any connection rule or SmartRoute questions to Tonto on
  18  * IRC or by email to vencill@bga.com.
  19  *
  20  * For parser testing, defining CR_DEBUG generates a stand-alone parser
  21  * that takes rules from stdin and prints out memory allocation
  22  * information and the parsed rule.  This stand alone parser is ignorant
  23  * of the irc server and thus cannot do rule evaluation.  Do not define
  24  * this flag when compiling the server!  If you wish to generate the
  25  * test parser, compile from the ircd directory with a line similar to
  26  * cc -o parser -DCR_DEBUG crule.c
  27  *
  28  * The define CR_CHKCONF is provided to generate routines needed in
  29  * chkconf.  These consist of the parser, a different crule_parse that
  30  * prints errors to stderr, and crule_free (just for good style and to
  31  * more closely simulate the actual ircd environment).  crule_eval and
  32  * the rule functions are made empty functions as in the stand-alone
  33  * test parser.
  34  *
  35  * The production rules for the grammar are as follows ("rule" is the
  36  * starting production):
  37  *
  38  *   rule:
  39  *     orexpr END          END is end of input or :
  40  *   orexpr:
  41  *     andexpr
  42  *     andexpr || orexpr
  43  *   andexpr:
  44  *     primary
  45  *     primary && andexpr
  46  *  primary:
  47  *    function
  48  *    ! primary
  49  *    ( orexpr )
  50  *  function:
  51  *    word ( )             word is alphanumeric string, first character
  52  *    word ( arglist )       must be a letter
  53  *  arglist:
  54  *    word
  55  *    word , arglist
  56  */
  57 #include "config.h"
  58
  59 #include "crule.h"
  60 #ifndef CR_DEBUG
  61
  62 /* ircd functions and types we need */
  63 #include "client.h"
  64 #include "ircd.h"
  65 #include "ircd_alloc.h"
  66 #include "ircd_chattr.h"
  67 #include "ircd_string.h"
  68 #include "match.h"
  69 #include "s_bsd.h"
  70 #include "s_debug.h"
  71 #include "struct.h"
  72
  73 #include <stdio.h>
  74 #include <stdlib.h>
  75
  76 #else /* includes and defines to make the stand-alone test parser */
  77
  78 #include <stdio.h>
  79 #include <stdlib.h>
  80
  81 #define BadPtr(x) (!(x) || (*(x) == '\0'))
  82 #define DupString(x,y) \
  83         do { \
  84           x = (char*) MyMalloc(strlen(y)+1); \
  85         strcpy(x,y); \
  86         } while(0)
  87
  88 /* We don't care about collation discrepancies here, it seems.... */
  89 #define ircd_strcmp strcasecmp
  90
  91 #endif
  92
  93 #include <string.h>
  94
  95
  96 #if defined(CR_DEBUG) || defined(CR_CHKCONF)
  97 #undef MyMalloc
  98 #undef malloc
  99 #define MyMalloc malloc
 100 #undef MyFree
 101 #undef free
 102 #define MyFree free
 103 #endif
 104
 105 /* some constants and shared data types */
 106 #define CR_MAXARGLEN 80         /**< Maximum arg length (must be > HOSTLEN) */
 107 #define CR_MAXARGS 3            /**< Maximum number of args for a rule */
 108
 109 /*
 110  * Some symbols for easy reading
 111  */
 112
 113 /** Input scanner tokens. */
 114 enum crule_token {
 115   CR_UNKNOWN,    /**< Unknown token type. */
 116   CR_END,        /**< End of input ('\\0' or ':'). */
 117   CR_AND,        /**< Logical and operator (&&). */
 118   CR_OR,         /**< Logical or operator (||). */
 119   CR_NOT,        /**< Logical not operator (!). */
 120   CR_OPENPAREN,  /**< Open parenthesis. */
 121   CR_CLOSEPAREN, /**< Close parenthesis. */
 122   CR_COMMA,      /**< Comma. */
 123   CR_WORD        /**< Something that looks like a hostmask (alphanumerics, "*?.-"). */
 124 };
 125
 126 /** Parser error codes. */
 127 enum crule_errcode {
 128   CR_NOERR,      /**< No error. */
 129   CR_UNEXPCTTOK, /**< Invalid token given context. */
 130   CR_UNKNWTOK,   /**< Input did not form a valid token. */
 131   CR_EXPCTAND,   /**< Did not see expected && operator. */
 132   CR_EXPCTOR,    /**< Did not see expected || operator. */
 133   CR_EXPCTPRIM,  /**< Expected a primitive (parentheses, ! or word). */
 134   CR_EXPCTOPEN,  /**< Expected an open parenthesis after function name. */
 135   CR_EXPCTCLOSE, /**< Expected a close parenthesis to match open parenthesis. */
 136   CR_UNKNWFUNC,  /**< Attempt to use an unknown function. */
 137   CR_ARGMISMAT   /**< Wrong number of arguments to function. */
 138 };
 139
 140 /*
 141  * Expression tree structure, function pointer, and tree pointer local!
 142  */
 143 /** Evaluation function for a connection rule. */
 144 typedef int (*crule_funcptr) (int, void **);
 145
 146 /** Node in a connection rule tree. */
 147 struct CRuleNode {
 148   crule_funcptr funcptr; /**< Evaluation function for this node. */
 149   int numargs;           /**< Number of arguments. */
 150   void *arg[CR_MAXARGS]; /**< Array of arguments.  For operators, each arg
 151                             is a tree element; for functions, each arg is
 152                             a string. */
 153 };
 154
 155 /** Typedef to save typing effort. */
 156 typedef struct CRuleNode* CRuleNodePtr;
 157
 158 /* local rule function prototypes */
 159 static int crule_connected(int, void *[]);
 160 static int crule_directcon(int, void *[]);
 161 static int crule_via(int, void *[]);
 162 static int crule_directop(int, void *[]);
 163 static int crule__andor(int, void *[]);
 164 static int crule__not(int, void *[]);
 165
 166 /* local parsing function prototypes */
 167 static int crule_gettoken(int* token, const char** str);
 168 static void crule_getword(char*, int*, size_t, const char**);
 169 static int crule_parseandexpr(CRuleNodePtr*, int *, const char**);
 170 static int crule_parseorexpr(CRuleNodePtr*, int *, const char**);
 171 static int crule_parseprimary(CRuleNodePtr*, int *, const char**);
 172 static int crule_parsefunction(CRuleNodePtr*, int *, const char**);
 173 static int crule_parsearglist(CRuleNodePtr, int *, const char**);
 174
 175 #if defined(CR_DEBUG) || defined(CR_CHKCONF)
 176 /*
 177  * Prototypes for the test parser; if not debugging,
 178  * these are defined in h.h
 179  */
 180 struct CRuleNode* crule_parse(const char*);
 181 void crule_free(struct CRuleNode**);
 182 #ifdef CR_DEBUG
 183 void print_tree(CRuleNodePtr);
 184 #endif
 185 #endif
 186
 187 /** Error messages, indexed by the corresponding crule_errcode. */
 188 char *crule_errstr[] = {
 189   "Unknown error",              /* NOERR? - for completeness */
 190   "Unexpected token",           /* UNEXPCTTOK */
 191   "Unknown token",              /* UNKNWTOK */
 192   "And expr expected",          /* EXPCTAND */
 193   "Or expr expected",           /* EXPCTOR */
 194   "Primary expected",           /* EXPCTPRIM */
 195   "( expected",                 /* EXPCTOPEN */
 196   ") expected",                 /* EXPCTCLOSE */
 197   "Unknown function",           /* UNKNWFUNC */
 198   "Argument mismatch"           /* ARGMISMAT */
 199 };
 200
 201 /** Connection rule function table entry. */
 202 struct crule_funclistent {
 203   char name[15];         /**< Function name. */
 204   int reqnumargs;        /**< Required number of arguments. */
 205   crule_funcptr funcptr; /**< Handler function. */
 206 };
 207
 208 /** Defined connection rules. */
 209 struct crule_funclistent crule_funclist[] = {
 210   /* maximum function name length is 14 chars */
 211   {"connected", 1, crule_connected},
 212   {"directcon", 1, crule_directcon},
 213   {"via", 2, crule_via},
 214   {"directop", 0, crule_directop},
 215   {"", 0, NULL}                 /* this must be here to mark end of list */
 216 };
 217
 218 /** Check whether any connected server matches crulearg[0].
 219  * @param[in] numargs Number of valid args in \a crulearg.
 220  * @param[in] crulearg Argument array.
 221  * @return Non-zero if the condition is true, zero if not.
 222  */
 223 static int crule_connected(int numargs, void *crulearg[])
 224 {
 225 #if !defined(CR_DEBUG) && !defined(CR_CHKCONF)
 226   struct Client *acptr;
 227
 228   /* taken from m_links */
 229   for (acptr = GlobalClientList; acptr; acptr = cli_next(acptr))
 230   {
 231     if (!IsServer(acptr) && !IsMe(acptr))
 232       continue;
 233     if (match((char *)crulearg[0], cli_name(acptr)))
 234       continue;
 235     return (1);
 236   }
 237 #endif
 238   return (0);
 239 }
 240
 241 /** Check whether any directly connected server matches crulearg[0].
 242  * @param[in] numargs Number of valid args in \a crulearg.
 243  * @param[in] crulearg Argument array.
 244  * @return Non-zero if the condition is true, zero if not.
 245  */
 246 static int crule_directcon(int numargs, void *crulearg[])
 247 {
 248 #if !defined(CR_DEBUG) && !defined(CR_CHKCONF)
 249   int i;
 250   struct Client *acptr;
 251
 252   /* adapted from m_trace and exit_one_client */
 253   for (i = 0; i <= HighestFd; i++)
 254   {
 255     if (!(acptr = LocalClientArray[i]) || !IsServer(acptr))
 256       continue;
 257     if (match((char *)crulearg[0], cli_name(acptr)))
 258       continue;
 259     return (1);
 260   }
 261 #endif
 262   return (0);
 263 }
 264
 265 /** Check whether a connected server matching crulearg[1] is
 266  * connnected to me behind one matching crulearg[0].
 267  * @param[in] numargs Number of valid args in \a crulearg.
 268  * @param[in] crulearg Argument array.
 269  * @return Non-zero if the condition is true, zero if not.
 270  */
 271 static int crule_via(int numargs, void *crulearg[])
 272 {
 273 #if !defined(CR_DEBUG) && !defined(CR_CHKCONF)
 274   struct Client *acptr;
 275
 276   /* adapted from m_links */
 277   for (acptr = GlobalClientList; acptr; acptr = cli_next(acptr))
 278   {
 279     if (!IsServer(acptr) && !IsMe(acptr))
 280       continue;
 281     if (match((char *)crulearg[1], cli_name(acptr)))
 282       continue;
 283     if (match((char *)crulearg[0], cli_name(cli_from(acptr))))
 284       continue;
 285     return (1);
 286   }
 287 #endif
 288   return (0);
 289 }
 290
 291 /** Check whether we have a local IRC operator.
 292  * @param[in] numargs Number of valid args in \a crulearg.
 293  * @param[in] crulearg Argument array.
 294  * @return Non-zero if the condition is true, zero if not.
 295  */
 296 static int crule_directop(int numargs, void *crulearg[])
 297 {
 298 #if !defined(CR_DEBUG) && !defined(CR_CHKCONF)
 299   int i;
 300   struct Client *acptr;
 301
 302   /* adapted from m_trace */
 303   for (i = 0; i <= HighestFd; i++)
 304   {
 305     if (!(acptr = LocalClientArray[i]) || !IsAnOper(acptr))
 306       continue;
 307     return (1);
 308   }
 309 #endif
 310   return (0);
 311 }
 312
 313 /** Evaluate a connection rule.
 314  * @param[in] rule Rule to evalute.
 315  * @return Non-zero if the rule allows the connection, zero otherwise.
 316  */
 317 int crule_eval(struct CRuleNode* rule)
 318 {
 319   return (rule->funcptr(rule->numargs, rule->arg));
 320 }
 321
 322 /** Perform an and-or-or test on crulearg[0] and crulearg[1].
 323  * If crulearg[2] is non-NULL, it means do OR; if it is NULL, do AND.
 324  * @param[in] numargs Number of valid args in \a crulearg.
 325  * @param[in] crulearg Argument array.
 326  * @return Non-zero if the condition is true, zero if not.
 327  */
 328 static int crule__andor(int numargs, void *crulearg[])
 329 {
 330   int result1;
 331
 332   result1 = crule_eval(crulearg[0]);
 333   if (crulearg[2])              /* or */
 334     return (result1 || crule_eval(crulearg[1]));
 335   else
 336     return (result1 && crule_eval(crulearg[1]));
 337 }
 338
 339 /** Logically invert the result of crulearg[0].
 340  * @param[in] numargs Number of valid args in \a crulearg.
 341  * @param[in] crulearg Argument array.
 342  * @return Non-zero if the condition is true, zero if not.
 343  */
 344 static int crule__not(int numargs, void *crulearg[])
 345 {
 346   return (!crule_eval(crulearg[0]));
 347 }
 348
 349 /** Scan an input token from \a ruleptr.
 350  * @param[out] next_tokp Receives type of next token.
 351  * @param[in,out] ruleptr Next readable character from input.
 352  * @return Either CR_UNKNWTOK if the input was unrecognizable, else CR_NOERR.
 353  */
 354 static int crule_gettoken(int* next_tokp, const char** ruleptr)
 355 {
 356   char pending = '\0';
 357
 358   *next_tokp = CR_UNKNOWN;
 359   while (*next_tokp == CR_UNKNOWN)
 360     switch (*(*ruleptr)++)
 361     {
 362       case ' ':
 363       case '\t':
 364         break;
 365       case '&':
 366         if (pending == '\0')
 367           pending = '&';
 368         else if (pending == '&')
 369           *next_tokp = CR_AND;
 370         else
 371           return (CR_UNKNWTOK);
 372         break;
 373       case '|':
 374         if (pending == '\0')
 375           pending = '|';
 376         else if (pending == '|')
 377           *next_tokp = CR_OR;
 378         else
 379           return (CR_UNKNWTOK);
 380         break;
 381       case '!':
 382         *next_tokp = CR_NOT;
 383         break;
 384       case '(':
 385         *next_tokp = CR_OPENPAREN;
 386         break;
 387       case ')':
 388         *next_tokp = CR_CLOSEPAREN;
 389         break;
 390       case ',':
 391         *next_tokp = CR_COMMA;
 392         break;
 393       case '\0':
 394         (*ruleptr)--;
 395         *next_tokp = CR_END;
 396         break;
 397       case ':':
 398         *next_tokp = CR_END;
 399         break;
 400       default:
 401         if ((IsAlpha(*(--(*ruleptr)))) || (**ruleptr == '*') ||
 402             (**ruleptr == '?') || (**ruleptr == '.') || (**ruleptr == '-'))
 403           *next_tokp = CR_WORD;
 404         else
 405           return (CR_UNKNWTOK);
 406         break;
 407     }
 408   return CR_NOERR;
 409 }
 410
 411 /** Scan a word from \a ruleptr.
 412  * @param[out] word Output buffer.
 413  * @param[out] wordlenp Length of word written to \a word (not including terminating NUL).
 414  * @param[in] maxlen Maximum number of bytes writable to \a word.
 415  * @param[in,out] ruleptr Next readable character from input.
 416  */
 417 static void crule_getword(char* word, int* wordlenp, size_t maxlen, const char** ruleptr)
 418 {
 419   char *word_ptr;
 420
 421   word_ptr = word;
 422   while ((size_t)(word_ptr - word) < maxlen
 423       && (IsAlnum(**ruleptr)
 424       || **ruleptr == '*' || **ruleptr == '?'
 425       || **ruleptr == '.' || **ruleptr == '-'))
 426     *word_ptr++ = *(*ruleptr)++;
 427   *word_ptr = '\0';
 428   *wordlenp = word_ptr - word;
 429 }
 430
 431 /** Parse an entire rule.
 432  * @param[in] rule Text form of rule.
 433  * @return CRuleNode for rule, or NULL if there was a parse error.
 434  */
 435 struct CRuleNode* crule_parse(const char *rule)
 436 {
 437   const char* ruleptr = rule;
 438   int next_tok;
 439   struct CRuleNode* ruleroot = 0;
 440   int errcode = CR_NOERR;
 441
 442   if ((errcode = crule_gettoken(&next_tok, &ruleptr)) == CR_NOERR) {
 443     if ((errcode = crule_parseorexpr(&ruleroot, &next_tok, &ruleptr)) == CR_NOERR) {
 444       if (ruleroot != NULL) {
 445         if (next_tok == CR_END)
 446           return (ruleroot);
 447         else
 448           errcode = CR_UNEXPCTTOK;
 449       }
 450       else
 451         errcode = CR_EXPCTOR;
 452     }
 453   }
 454   if (ruleroot != NULL)
 455     crule_free(&ruleroot);
 456 #if !defined(CR_DEBUG) && !defined(CR_CHKCONF)
 457   Debug((DEBUG_ERROR, "%s in rule: %s", crule_errstr[errcode], rule));
 458 #else
 459   fprintf(stderr, "%s in rule: %s\n", crule_errstr[errcode], rule);
 460 #endif
 461   return 0;
 462 }
 463
 464 /** Parse an or expression.
 465  * @param[out] orrootp Receives parsed node.
 466  * @param[in,out] next_tokp Next input token type.
 467  * @param[in,out] ruleptr Next input character.
 468  * @return A crule_errcode value.
 469  */
 470 static int crule_parseorexpr(CRuleNodePtr * orrootp, int *next_tokp, const char** ruleptr)
 471 {
 472   int errcode = CR_NOERR;
 473   CRuleNodePtr andexpr;
 474   CRuleNodePtr orptr;
 475
 476   *orrootp = NULL;
 477   while (errcode == CR_NOERR)
 478   {
 479     errcode = crule_parseandexpr(&andexpr, next_tokp, ruleptr);
 480     if ((errcode == CR_NOERR) && (*next_tokp == CR_OR))
 481     {
 482       orptr = (CRuleNodePtr) MyMalloc(sizeof(struct CRuleNode));
 483 #ifdef CR_DEBUG
 484       fprintf(stderr, "allocating or element at %ld\n", orptr);
 485 #endif
 486       orptr->funcptr = crule__andor;
 487       orptr->numargs = 3;
 488       orptr->arg[2] = (void *)1;
 489       if (*orrootp != NULL)
 490       {
 491         (*orrootp)->arg[1] = andexpr;
 492         orptr->arg[0] = *orrootp;
 493       }
 494       else
 495         orptr->arg[0] = andexpr;
 496       *orrootp = orptr;
 497     }
 498     else
 499     {
 500       if (*orrootp != NULL)
 501       {
 502         if (andexpr != NULL)
 503         {
 504           (*orrootp)->arg[1] = andexpr;
 505           return (errcode);
 506         }
 507         else
 508         {
 509           (*orrootp)->arg[1] = NULL;    /* so free doesn't seg fault */
 510           return (CR_EXPCTAND);
 511         }
 512       }
 513       else
 514       {
 515         *orrootp = andexpr;
 516         return (errcode);
 517       }
 518     }
 519     if ((errcode = crule_gettoken(next_tokp, ruleptr)) != CR_NOERR)
 520       return (errcode);
 521   }
 522   return (errcode);
 523 }
 524
 525 /** Parse an and expression.
 526  * @param[out] androotp Receives parsed node.
 527  * @param[in,out] next_tokp Next input token type.
 528  * @param[in,out] ruleptr Next input character.
 529  * @return A crule_errcode value.
 530  */
 531 static int crule_parseandexpr(CRuleNodePtr * androotp, int *next_tokp, const char** ruleptr)
 532 {
 533   int errcode = CR_NOERR;
 534   CRuleNodePtr primary;
 535   CRuleNodePtr andptr;
 536
 537   *androotp = NULL;
 538   while (errcode == CR_NOERR)
 539   {
 540     errcode = crule_parseprimary(&primary, next_tokp, ruleptr);
 541     if ((errcode == CR_NOERR) && (*next_tokp == CR_AND))
 542     {
 543       andptr = (CRuleNodePtr) MyMalloc(sizeof(struct CRuleNode));
 544 #ifdef CR_DEBUG
 545       fprintf(stderr, "allocating and element at %ld\n", andptr);
 546 #endif
 547       andptr->funcptr = crule__andor;
 548       andptr->numargs = 3;
 549       andptr->arg[2] = (void *)0;
 550       if (*androotp != NULL)
 551       {
 552         (*androotp)->arg[1] = primary;
 553         andptr->arg[0] = *androotp;
 554       }
 555       else
 556         andptr->arg[0] = primary;
 557       *androotp = andptr;
 558     }
 559     else
 560     {
 561       if (*androotp != NULL)
 562       {
 563         if (primary != NULL)
 564         {
 565           (*androotp)->arg[1] = primary;
 566           return (errcode);
 567         }
 568         else
 569         {
 570           (*androotp)->arg[1] = NULL;   /* so free doesn't seg fault */
 571           return (CR_EXPCTPRIM);
 572         }
 573       }
 574       else
 575       {
 576         *androotp = primary;
 577         return (errcode);
 578       }
 579     }
 580     if ((errcode = crule_gettoken(next_tokp, ruleptr)) != CR_NOERR)
 581       return (errcode);
 582   }
 583   return (errcode);
 584 }
 585
 586 /** Parse a primary expression.
 587  * @param[out] primrootp Receives parsed node.
 588  * @param[in,out] next_tokp Next input token type.
 589  * @param[in,out] ruleptr Next input character.
 590  * @return A crule_errcode value.
 591  */
 592 static int crule_parseprimary(CRuleNodePtr* primrootp, int *next_tokp, const char** ruleptr)
 593 {
 594   CRuleNodePtr *insertionp;
 595   int errcode = CR_NOERR;
 596
 597   *primrootp = NULL;
 598   insertionp = primrootp;
 599   while (errcode == CR_NOERR)
 600   {
 601     switch (*next_tokp)
 602     {
 603       case CR_OPENPAREN:
 604         if ((errcode = crule_gettoken(next_tokp, ruleptr)) != CR_NOERR)
 605           break;
 606         if ((errcode = crule_parseorexpr(insertionp, next_tokp, ruleptr)) != CR_NOERR)
 607           break;
 608         if (*insertionp == NULL)
 609         {
 610           errcode = CR_EXPCTAND;
 611           break;
 612         }
 613         if (*next_tokp != CR_CLOSEPAREN)
 614         {
 615           errcode = CR_EXPCTCLOSE;
 616           break;
 617         }
 618         errcode = crule_gettoken(next_tokp, ruleptr);
 619         break;
 620       case CR_NOT:
 621         *insertionp = (CRuleNodePtr) MyMalloc(sizeof(struct CRuleNode));
 622 #ifdef CR_DEBUG
 623         fprintf(stderr, "allocating primary element at %ld\n", *insertionp);
 624 #endif
 625         (*insertionp)->funcptr = crule__not;
 626         (*insertionp)->numargs = 1;
 627         (*insertionp)->arg[0] = NULL;
 628         insertionp = (CRuleNodePtr *) & ((*insertionp)->arg[0]);
 629         if ((errcode = crule_gettoken(next_tokp, ruleptr)) != CR_NOERR)
 630           break;
 631         continue;
 632       case CR_WORD:
 633         errcode = crule_parsefunction(insertionp, next_tokp, ruleptr);
 634         break;
 635       default:
 636         if (*primrootp == NULL)
 637           errcode = CR_NOERR;
 638         else
 639           errcode = CR_EXPCTPRIM;
 640         break;
 641     }
 642     return (errcode);
 643   }
 644   return (errcode);
 645 }
 646
 647 /** Parse a function call.
 648  * @param[out] funcrootp Receives parsed node.
 649  * @param[in,out] next_tokp Next input token type.
 650  * @param[in,out] ruleptr Next input character.
 651  * @return A crule_errcode value.
 652  */
 653 static int crule_parsefunction(CRuleNodePtr* funcrootp, int* next_tokp, const char** ruleptr)
 654 {
 655   int errcode = CR_NOERR;
 656   char funcname[CR_MAXARGLEN];
 657   int namelen;
 658   int funcnum;
 659
 660   *funcrootp = NULL;
 661   crule_getword(funcname, &namelen, CR_MAXARGLEN - 1, ruleptr);
 662   if ((errcode = crule_gettoken(next_tokp, ruleptr)) != CR_NOERR)
 663     return (errcode);
 664   if (*next_tokp == CR_OPENPAREN)
 665   {
 666     for (funcnum = 0;; funcnum++)
 667     {
 668       if (0 == ircd_strcmp(crule_funclist[funcnum].name, funcname))
 669         break;
 670       if (crule_funclist[funcnum].name[0] == '\0')
 671         return (CR_UNKNWFUNC);
 672     }
 673     if ((errcode = crule_gettoken(next_tokp, ruleptr)) != CR_NOERR)
 674       return (errcode);
 675     *funcrootp = (CRuleNodePtr) MyMalloc(sizeof(struct CRuleNode));
 676 #ifdef CR_DEBUG
 677     fprintf(stderr, "allocating function element at %ld\n", *funcrootp);
 678 #endif
 679     (*funcrootp)->funcptr = NULL;       /* for freeing aborted trees */
 680     if ((errcode =
 681         crule_parsearglist(*funcrootp, next_tokp, ruleptr)) != CR_NOERR)
 682       return (errcode);
 683     if (*next_tokp != CR_CLOSEPAREN)
 684       return (CR_EXPCTCLOSE);
 685     if ((crule_funclist[funcnum].reqnumargs != (*funcrootp)->numargs) &&
 686         (crule_funclist[funcnum].reqnumargs != -1))
 687       return (CR_ARGMISMAT);
 688     if ((errcode = crule_gettoken(next_tokp, ruleptr)) != CR_NOERR)
 689       return (errcode);
 690     (*funcrootp)->funcptr = crule_funclist[funcnum].funcptr;
 691     return (CR_NOERR);
 692   }
 693   else
 694     return (CR_EXPCTOPEN);
 695 }
 696
 697 /** Parse the argument list to a CRuleNode.
 698  * @param[in,out] argrootp Node whos argument list is being populated.
 699  * @param[in,out] next_tokp Next input token type.
 700  * @param[in,out] ruleptr Next input character.
 701  * @return A crule_errcode value.
 702  */
 703 static int crule_parsearglist(CRuleNodePtr argrootp, int *next_tokp, const char** ruleptr)
 704 {
 705   int errcode = CR_NOERR;
 706   char *argelemp = NULL;
 707   char currarg[CR_MAXARGLEN];
 708   int arglen = 0;
 709   char word[CR_MAXARGLEN];
 710   int wordlen = 0;
 711
 712   argrootp->numargs = 0;
 713   currarg[0] = '\0';
 714   while (errcode == CR_NOERR)
 715   {
 716     switch (*next_tokp)
 717     {
 718       case CR_WORD:
 719         crule_getword(word, &wordlen, CR_MAXARGLEN - 1, ruleptr);
 720         if (currarg[0] != '\0')
 721         {
 722           if ((arglen + wordlen) < (CR_MAXARGLEN - 1))
 723           {
 724             strcat(currarg, " ");
 725             strcat(currarg, word);
 726             arglen += wordlen + 1;
 727           }
 728         }
 729         else
 730         {
 731           strcpy(currarg, word);
 732           arglen = wordlen;
 733         }
 734         errcode = crule_gettoken(next_tokp, ruleptr);
 735         break;
 736       default:
 737 #if !defined(CR_DEBUG) && !defined(CR_CHKCONF)
 738         collapse(currarg);
 739 #endif
 740         if (!BadPtr(currarg))
 741         {
 742           DupString(argelemp, currarg);
 743           argrootp->arg[argrootp->numargs++] = (void *)argelemp;
 744         }
 745         if (*next_tokp != CR_COMMA)
 746           return (CR_NOERR);
 747         currarg[0] = '\0';
 748         errcode = crule_gettoken(next_tokp, ruleptr);
 749         break;
 750     }
 751   }
 752   return (errcode);
 753 }
 754
 755 /*
 756  * This function is recursive..  I wish I knew a nonrecursive way but
 757  * I don't.  Anyway, recursion is fun..  :)
 758  * DO NOT CALL THIS FUNCTION WITH A POINTER TO A NULL POINTER
 759  * (i.e.: If *elem is NULL, you're doing it wrong - seg fault)
 760  */
 761 /** Free a connection rule and all its children.
 762  * @param[in,out] elem Pointer to pointer to element to free.  MUST NOT BE NULL.
 763  */
 764 void crule_free(struct CRuleNode** elem)
 765 {
 766   int arg, numargs;
 767
 768   if ((*(elem))->funcptr == crule__not)
 769   {
 770     /* type conversions and ()'s are fun! ;)  here have an aspirin.. */
 771     if ((*(elem))->arg[0] != NULL)
 772       crule_free((struct CRuleNode**) &((*(elem))->arg[0]));
 773   }
 774   else if ((*(elem))->funcptr == crule__andor)
 775   {
 776     crule_free((struct CRuleNode**) &((*(elem))->arg[0]));
 777     if ((*(elem))->arg[1] != NULL)
 778       crule_free((struct CRuleNode**) &((*(elem))->arg[1]));
 779   }
 780   else
 781   {
 782     numargs = (*(elem))->numargs;
 783     for (arg = 0; arg < numargs; arg++)
 784       MyFree((*(elem))->arg[arg]);
 785   }
 786 #ifdef CR_DEBUG
 787   fprintf(stderr, "freeing element at %ld\n", *elem);
 788 #endif
 789   MyFree(*elem);
 790   *elem = 0;
 791 }
 792
 793 #ifdef CR_DEBUG
 794 /** Display a connection rule as text.
 795  * @param[in] printelem Connection rule to display.
 796  */
 797 static void print_tree(CRuleNodePtr printelem)
 798 {
 799   int funcnum, arg;
 800
 801   if (printelem->funcptr == crule__not)
 802   {
 803     printf("!( ");
 804     print_tree((CRuleNodePtr) printelem->arg[0]);
 805     printf(") ");
 806   }
 807   else if (printelem->funcptr == crule__andor)
 808   {
 809     printf("( ");
 810     print_tree((CRuleNodePtr) printelem->arg[0]);
 811     if (printelem->arg[2])
 812       printf("|| ");
 813     else
 814       printf("&& ");
 815     print_tree((CRuleNodePtr) printelem->arg[1]);
 816     printf(") ");
 817   }
 818   else
 819   {
 820     for (funcnum = 0;; funcnum++)
 821     {
 822       if (printelem->funcptr == crule_funclist[funcnum].funcptr)
 823         break;
 824       if (crule_funclist[funcnum].funcptr == NULL)
 825         MyCoreDump;
 826     }
 827     printf("%s(", crule_funclist[funcnum].name);
 828     for (arg = 0; arg < printelem->numargs; arg++)
 829     {
 830       if (arg != 0)
 831         printf(",");
 832       printf("%s", (char *)printelem->arg[arg]);
 833     }
 834     printf(") ");
 835   }
 836 }
 837
 838 #endif
 839
 840 #ifdef CR_DEBUG
 841 /** Read connection rules from stdin and display parsed forms as text.
 842  * @return Zero.
 843  */
 844 int main(void)
 845 {
 846   char indata[256];
 847   CRuleNode* rule;
 848
 849   printf("rule: ");
 850   while (fgets(indata, 256, stdin) != NULL)
 851   {
 852     indata[strlen(indata) - 1] = '\0';  /* lose the newline */
 853     if ((rule = crule_parse(indata)) != NULL)
 854     {
 855       printf("equivalent rule: ");
 856       print_tree((CRuleNodePtr) rule);
 857       printf("\n");
 858       crule_free(&rule);
 859     }
 860     printf("\nrule: ");
 861   }
 862   printf("\n");
 863
 864   return 0;
 865 }
 866
 867 #endif