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Annotation of 43BSDReno/usr.sbin/named/db_lookup.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1986 Regents of the University of California.
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * Redistribution and use in source and binary forms are permitted provided
        !             6:  * that: (1) source distributions retain this entire copyright notice and
        !             7:  * comment, and (2) distributions including binaries display the following
        !             8:  * acknowledgement:  ``This product includes software developed by the
        !             9:  * University of California, Berkeley and its contributors'' in the
        !            10:  * documentation or other materials provided with the distribution and in
        !            11:  * all advertising materials mentioning features or use of this software.
        !            12:  * Neither the name of the University nor the names of its contributors may
        !            13:  * be used to endorse or promote products derived from this software without
        !            14:  * specific prior written permission.
        !            15:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
        !            16:  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
        !            17:  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            18:  */
        !            19: 
        !            20: #ifndef lint
        !            21: static char sccsid[] = "@(#)db_lookup.c        4.17 (Berkeley) 6/1/90";
        !            22: #endif /* not lint */
        !            23: 
        !            24: /*
        !            25:  * Table lookup routines.
        !            26:  */
        !            27: 
        !            28: #include <sys/types.h>
        !            29: #include <stdio.h>
        !            30: #include <arpa/nameser.h>
        !            31: #include "db.h"
        !            32: 
        !            33: struct hashbuf *hashtab;       /* root hash table */
        !            34: struct hashbuf *fcachetab;     /* hash table of cache read from file */
        !            35: 
        !            36: #ifdef DEBUG
        !            37: extern int debug;
        !            38: extern FILE *ddt;
        !            39: #endif
        !            40: 
        !            41: /* 
        !            42:  * Lookup 'name' and return a pointer to the namebuf;
        !            43:  * NULL otherwise. If 'insert', insert name into tables.
        !            44:  * Wildcard lookups are handled.
        !            45:  */
        !            46: struct namebuf *
        !            47: nlookup(name, htpp, fname, insert)
        !            48:        char *name;
        !            49:        struct hashbuf **htpp;
        !            50:        char **fname;
        !            51:        int insert;
        !            52: {
        !            53:        register struct namebuf *np;
        !            54:        register char *cp;
        !            55:        register int c;
        !            56:        register unsigned hval;
        !            57:        register struct hashbuf *htp;
        !            58:        struct namebuf *parent = NULL;
        !            59: 
        !            60:        htp = *htpp;
        !            61:        hval = 0;
        !            62:        *fname = "???";
        !            63:        for (cp = name; c = *cp++; ) {
        !            64:                if (c == '.') {
        !            65:                        parent = np = nlookup(cp, htpp, fname, insert);
        !            66:                        if (np == NULL)
        !            67:                                return (NULL);
        !            68:                        if (*fname != cp)
        !            69:                                return (np);
        !            70:                        if ((htp = np->n_hash) == NULL) {
        !            71:                                if (!insert) {
        !            72:                                        if (np->n_dname[0] == '*' && 
        !            73:                                            np->n_dname[1] == '\0')
        !            74:                                                *fname = name;
        !            75:                                        return (np);
        !            76:                                }
        !            77:                                htp = savehash((struct hashbuf *)NULL);
        !            78:                                np->n_hash = htp;
        !            79:                        }
        !            80:                        *htpp = htp;
        !            81:                        break;
        !            82:                }
        !            83:                hval <<= HASHSHIFT;
        !            84:                hval += c & HASHMASK;
        !            85:        }
        !            86:        c = *--cp;
        !            87:        *cp = '\0';
        !            88:        /*
        !            89:         * Lookup this label in current hash table.
        !            90:         */
        !            91:        for (np = htp->h_tab[hval % htp->h_size]; np != NULL; np = np->n_next) {
        !            92:                if (np->n_hashval == hval &&
        !            93:                    strcasecmp(name, np->n_dname) == 0) {
        !            94:                        *cp = c;
        !            95:                        *fname = name;
        !            96:                        return (np);
        !            97:                }
        !            98:        }
        !            99:        if (!insert) {
        !           100:                /*
        !           101:                 * Look for wildcard in this hash table.
        !           102:                 * Don't use a cached "*" name as a wildcard,
        !           103:                 * only authoritative.
        !           104:                 */
        !           105:                hval = ('*' & HASHMASK)  % htp->h_size;
        !           106:                for (np = htp->h_tab[hval]; np != NULL; np = np->n_next) {
        !           107:                        if (np->n_dname[0] == '*'  && np->n_dname[1] == '\0' &&
        !           108:                            np->n_data && np->n_data->d_zone != 0) {
        !           109:                                *cp = c;
        !           110:                                *fname = name;
        !           111:                                return (np);
        !           112:                        }
        !           113:                }
        !           114:                *cp = c;
        !           115:                return (parent);
        !           116:        }
        !           117:        np = savename(name);
        !           118:        np->n_parent = parent;
        !           119:        np->n_hashval = hval;
        !           120:        hval %= htp->h_size;
        !           121:        np->n_next = htp->h_tab[hval];
        !           122:        htp->h_tab[hval] = np;
        !           123:        /* increase hash table size */
        !           124:        if (++htp->h_cnt > htp->h_size * 2) {
        !           125:                *htpp = savehash(htp);
        !           126:                if (parent == NULL) {
        !           127:                        if (htp == hashtab)
        !           128:                            hashtab = *htpp;
        !           129:                        else
        !           130:                            fcachetab = *htpp;
        !           131:                }
        !           132:                else
        !           133:                        parent->n_hash = *htpp;
        !           134:                htp = *htpp;
        !           135:        }
        !           136:        *cp = c;
        !           137:        *fname = name;
        !           138:        return (np);
        !           139: }
        !           140: 
        !           141: /*
        !           142:  * Does the data record match the class and type?
        !           143:  */
        !           144: match(dp, class, type)
        !           145:        register struct databuf *dp;
        !           146:        register int class, type;
        !           147: {
        !           148: #ifdef DEBUG
        !           149:        if (debug >= 5)
        !           150:                fprintf(ddt,"match(0x%x, %d, %d) %d, %d\n", dp, class, type,
        !           151:                        dp->d_class, dp->d_type);
        !           152: #endif
        !           153:        if (dp->d_class != class && class != C_ANY)
        !           154:                return (0);
        !           155:        if (dp->d_type != type && type != T_ANY)
        !           156:                return (0);
        !           157:        return (1);
        !           158: }

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