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Diffstat (limited to 'contrib/bind/doc/notes/db_names.c')
| -rw-r--r-- | contrib/bind/doc/notes/db_names.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/contrib/bind/doc/notes/db_names.c b/contrib/bind/doc/notes/db_names.c new file mode 100644 index 000000000000..0b4e62c78b83 --- /dev/null +++ b/contrib/bind/doc/notes/db_names.c @@ -0,0 +1,184 @@ +/* + * Copyright (c) 1996,1999 by Internet Software Consortium. + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS + * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE + * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL + * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR + * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS + * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS + * SOFTWARE. + */ + +#include <sys/types.h> +#include <sys/param.h> +#include <netinet/in.h> +#include <arpa/nameser.h> + +#include <ctype.h> +#include <errno.h> +#include <resolv.h> +#include <stdio.h> + +#include "named.h" +#include "tree.h" + +struct node { + struct node *parent; /* NULL for "."'s node. */ + tree *children; /* Nodes using us as parent. */ + /*void *userdata;*/ /* For future use. */ + char name[sizeof(void*)]; /* Open array. */ +}; + +static struct node rootNode; + +static int +nodeCompare(t1, t2) + const tree_t t1, t2; +{ + const char *n1 = ((struct node *)t1)->name + sizeof(u_char), + *n2 = ((struct node *)t2)->name + sizeof(u_char); + + return (strcasecmp(n1, n2)); +} + +/* void * + * db_findname(const char *name, int storeflag) + * find or store a presentation format domain name. + * returns: + * NULL if an error occurred (check errno) + * else, node's unique, opaque address. + */ +void * +db_findname(name, storeflag) + const char *name; + int storeflag; +{ + struct node *node, *tnode; + const char *tname; + size_t len; + int ch; + + /* The root domain has its own static node. */ + if (name[0] == '\0') + return (&rootNode); + + /* Locate the end of the first label. */ + for (tname = name; (ch = *tname) != '\0'; tname++) { + /* Is this the end of the first label? */ + if (ch == '.') + break; + /* Is it an escaped character? */ + if (ch == '\\') { + ch = *++tname; + if (ch == '\0') + break; + } + } + + /* Make sure the label's length will fit in our length byte. */ + len = tname - name; + if (len > 255) { + errno = ENAMETOOLONG; + return (NULL); + } + + /* If nothing but unescaped dots after this, elide them. */ + while (ch == '.') + ch = *tname++; + + /* + * Make a new node since the comparison function needs it + * and we may yet end up adding it to our parent's tree. + * + * Note that by recursing for tnode->parent, we might be + * creating our parents and grandparents and so on. + */ + tnode = (struct node *)malloc(sizeof(struct node) - sizeof(void *) + + sizeof(u_char) + len + sizeof(char)); + tnode->parent = db_findname(tname); + tnode->children = NULL; + *((u_char *)tnode->name) = (u_char)len; + memcpy(tnode->name + sizeof(u_char), name, len); + tnode->name[sizeof(u_char) + len] = '\0'; + + /* If our first label isn't in our parent's tree, put it there. */ + node = tree_srch(&tnode->parent->children, nodeCompare, (tree_t)tnode); + if (node == NULL) + if (storeflag) + if (tree_add(&tnode->parent->children, nodeCompare, + (tree_t)tnode, NULL)) + node = tnode, tnode = NULL; + else + errno = ENOMEM; + else + errno = ENOENT; + + /* Get rid of tnode if we didn't consume it. */ + if (tnode != NULL) + free(tnode); + + /* Return the (possibly new) node, or NULL, as appropriate. */ + return (node); +} + +/* int + * db_getname(void *node, char *name, size_t size) + * given a node's unique, opaque address, format its name. + * returns: + * -1 = error occurred, check errno + * 0 = success + */ +int +db_getname(vnode, name, size) + const void *vnode; + char *name; + size_t size; +{ + const struct node *node = vnode; + + while (node != NULL) { + size_t len = (size_t)node->name[0]; + + if (size < len + 1) + goto too_long; + memcpy(name, node->name + sizeof(u_char), len); + name += len; + *name++ = '.'; + size -= len + sizeof(char); + node = node->parent; + } + + if (size < sizeof(char)) { + too_long: + errno = ENAMETOOLONG; + return (-1); + } + *name = '\0'; + return (0); +} + +/* + * char * + * db_makename(void *node) + * given a node's unique, opaque address, format and return its name. + * returns: + * pointer to the name or NULL on errors (check errno). + * notes: + * returns pointer to a static buffer, be careful how you call it. + */ +char * +db_makename(vnode) + void *vnode; +{ + static char name[MAXDNAME*2]; + + if (db_getname(vnode, name, sizeof name) < 0) + return (NULL); + return (name); +} |