/*
* Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
+ * Copyright (C) 2008 Alan Jenkins <alan-jenkins@tuffmail.co.uk>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
};
};
-struct trie_child {
- unsigned int next_idx;
- unsigned int node_idx;
- unsigned char key;
-};
-
struct trie_node {
+ /* this node's first child */
unsigned int child_idx;
+ /* the next child of our parent node's child list */
+ unsigned int next_child_idx;
+ /* this node's last child (shortcut for append) */
unsigned int last_child_idx;
unsigned int value_off;
unsigned short value_len;
+ unsigned char key;
};
struct udev_rules {
unsigned int buf_count;
/* during rule parsing, strings are indexed to find duplicates */
- unsigned int *trie_root;
struct trie_node *trie_nodes;
unsigned int trie_nodes_cur;
unsigned int trie_nodes_max;
- struct trie_child *trie_childs;
- unsigned int trie_childs_cur;
- unsigned int trie_childs_max;
/* during rule parsing, uid/gid lookup results are cached */
struct uid_gid *uids;
unsigned short len;
unsigned int depth;
unsigned int off;
+ struct trie_node *parent;
len = strlen(str);
if (len == 0)
return 0;
- /* descend root - start from last character of str */
- key = str[len - 1];
- node_idx = rules->trie_root[key];
- depth = 0;
-
- /* descend suffix trie */
- if (node_idx > 0) {
- while (1) {
- struct trie_node *node;
- unsigned int child_idx;
-
- node = &rules->trie_nodes[node_idx];
- depth++;
- off = node->value_off + node->value_len - len;
-
- /* match against current node */
- if (depth == len || (node->value_len >= len && memcmp(&rules->buf[off], str, len) == 0))
- return off;
-
- /* lookup child node */
- key = str[len - 1 - depth];
- child_idx = node->child_idx;
- while (child_idx > 0) {
- if (rules->trie_childs[child_idx].key == key)
- break;
- child_idx = rules->trie_childs[child_idx].next_idx;
- }
- if (child_idx == 0)
+ /* walk trie, start from last character of str to find matching tails */
+ node_idx = 0;
+ key = str[len-1];
+ for (depth = 0; depth <= len; depth++) {
+ struct trie_node *node;
+ unsigned int child_idx;
+
+ node = &rules->trie_nodes[node_idx];
+ off = node->value_off + node->value_len - len;
+
+ /* match against current node */
+ if (depth == len || (node->value_len >= len && memcmp(&rules->buf[off], str, len) == 0))
+ return off;
+
+ /* lookup child node */
+ key = str[len - 1 - depth];
+ child_idx = node->child_idx;
+ while (child_idx > 0) {
+ struct trie_node *child;
+
+ child = &rules->trie_nodes[child_idx];
+ if (child->key == key)
break;
- node_idx = rules->trie_childs[child_idx].node_idx;
+ child_idx = child->next_child_idx;
}
+ if (child_idx == 0)
+ break;
+ node_idx = child_idx;
}
/* string not found, add it */
rules->trie_nodes_max += add;
}
- /* grow trie childs if needed */
- if (rules->trie_childs_cur >= rules->trie_childs_max) {
- struct trie_child *childs;
- unsigned int add;
-
- /* double the buffer size */
- add = rules->trie_childs_max;
- if (add < 8)
- add = 8;
-
- childs = realloc(rules->trie_childs, (rules->trie_childs_max + add) * sizeof(struct trie_child));
- if (childs == NULL)
- return -1;
- dbg(rules->udev, "extend trie childs from %u to %u\n",
- rules->trie_childs_max, rules->trie_childs_max + add);
- rules->trie_childs = childs;
- rules->trie_childs_max += add;
- }
-
- /* get new node */
+ /* get a new node */
new_node_idx = rules->trie_nodes_cur;
rules->trie_nodes_cur++;
new_node = &rules->trie_nodes[new_node_idx];
+ memset(new_node, 0x00, sizeof(struct trie_node));
new_node->value_off = off;
new_node->value_len = len;
- new_node->child_idx = 0;
- new_node->last_child_idx = 0;
+ new_node->key = key;
- if (depth == 0) {
- /* add node to root */
- rules->trie_root[key] = new_node_idx;
+ /* join the parent's child list */
+ parent = &rules->trie_nodes[node_idx];
+ if (parent->child_idx == 0) {
+ parent->child_idx = new_node_idx;
} else {
- /* add node to parent */
- struct trie_node *parent;
- struct trie_child *new_child;
- unsigned int new_child_idx;
-
- /* get new child link for list of childs of parent */
- new_child_idx = rules->trie_childs_cur;
- rules->trie_childs_cur++;
- new_child = &rules->trie_childs[new_child_idx];
- new_child->next_idx = 0;
- new_child->node_idx = new_node_idx;
- new_child->key = key;
-
- /* append child link to list of childs of parent */
- parent = &rules->trie_nodes[node_idx];
- if (parent->child_idx == 0) {
- parent->child_idx = new_child_idx;
- } else {
- struct trie_child *last_child;
+ struct trie_node *last_child;
- last_child = &rules->trie_childs[parent->last_child_idx];
- last_child->next_idx = new_child_idx;
- }
- parent->last_child_idx = new_child_idx;
+ last_child = &rules->trie_nodes[parent->last_child_idx];
+ last_child->next_child_idx = new_node_idx;
}
+ parent->last_child_idx = new_node_idx;
return off;
}
if (rules->trie_nodes == NULL)
return NULL;
rules->trie_nodes_max = PREALLOC_TRIE;
- /* offset 0 is reserved for the null trie node */
+ /* offset 0 is the trie root */
+ memset(rules->trie_nodes, 0x00, sizeof(struct trie_node));
rules->trie_nodes_cur = 1;
- rules->trie_childs = malloc(PREALLOC_TRIE * sizeof(struct trie_child));
- if (rules->trie_childs == NULL)
- return NULL;
- rules->trie_childs_max = PREALLOC_TRIE;
- /* offset 0 is reserved for the null child node */
- rules->trie_childs_cur = 1;
-
- rules->trie_root = calloc(UCHAR_MAX + 1, sizeof(unsigned short));
-
if (udev_get_rules_path(udev) != NULL) {
/* custom rules location for testing */
add_matching_files(udev, &file_list, udev_get_rules_path(udev), ".rules");
}
info(udev, "rules use %zu bytes tokens (%u * %zu bytes), %zu bytes buffer\n",
rules->token_max * sizeof(struct token), rules->token_max, sizeof(struct token), rules->buf_max);
- info(udev, "temporary index used %zu bytes (%u * %zu bytes nodes, %u * %zu bytes child links)\n",
- rules->trie_nodes_cur * sizeof(struct trie_node) + rules->trie_childs_cur * sizeof(struct trie_child),
- rules->trie_nodes_cur, sizeof(struct trie_node),
- rules->trie_childs_cur, sizeof(struct trie_child));
+ info(udev, "temporary index used %zu bytes (%u * %zu bytes)\n",
+ rules->trie_nodes_cur * sizeof(struct trie_node),
+ rules->trie_nodes_cur, sizeof(struct trie_node));
/* cleanup trie */
free(rules->trie_nodes);
rules->trie_nodes = NULL;
rules->trie_nodes_cur = 0;
rules->trie_nodes_max = 0;
- free(rules->trie_childs);
- rules->trie_childs = NULL;
- rules->trie_childs_cur = 0;
- rules->trie_childs_max = 0;
- free(rules->trie_root);
- rules->trie_root = NULL;
/* cleanup uid/gid cache */
free(rules->uids);
free(rules->tokens);
free(rules->buf);
free(rules->trie_nodes);
- free(rules->trie_childs);
- free(rules->trie_root);
free(rules->uids);
free(rules->gids);
free(rules);
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