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      1 /*
      2  * Copyright 2014 Tresys Technology, LLC. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are met:
      6  *
      7  *    1. Redistributions of source code must retain the above copyright notice,
      8  *       this list of conditions and the following disclaimer.
      9  *
     10  *    2. Redistributions in binary form must reproduce the above copyright notice,
     11  *       this list of conditions and the following disclaimer in the documentation
     12  *       and/or other materials provided with the distribution.
     13  *
     14  * THIS SOFTWARE IS PROVIDED BY TRESYS TECHNOLOGY, LLC ``AS IS'' AND ANY EXPRESS
     15  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     16  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     17  * EVENT SHALL TRESYS TECHNOLOGY, LLC OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
     18  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     19  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     21  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
     22  * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     23  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  *
     25  * The views and conclusions contained in the software and documentation are those
     26  * of the authors and should not be interpreted as representing official policies,
     27  * either expressed or implied, of Tresys Technology, LLC.
     28  */
     29 
     30 #include <stdlib.h>
     31 #include <stdio.h>
     32 #include <string.h>
     33 #include "cil_mem.h"
     34 #include "cil_strpool.h"
     35 
     36 #include "cil_log.h"
     37 #define CIL_STRPOOL_TABLE_SIZE 1 << 15
     38 
     39 struct cil_strpool_entry {
     40 	char *str;
     41 };
     42 
     43 static hashtab_t cil_strpool_tab = NULL;
     44 
     45 static unsigned int cil_strpool_hash(hashtab_t h, hashtab_key_t key)
     46 {
     47 	char *p, *keyp;
     48 	size_t size;
     49 	unsigned int val;
     50 
     51 	val = 0;
     52 	keyp = (char*)key;
     53 	size = strlen(keyp);
     54 	for (p = keyp; ((size_t) (p - keyp)) < size; p++)
     55 		val =
     56 		    (val << 4 | (val >> (8 * sizeof(unsigned int) - 4))) ^ (*p);
     57 	return val & (h->size - 1);
     58 }
     59 
     60 static int cil_strpool_compare(hashtab_t h __attribute__ ((unused)), hashtab_key_t key1, hashtab_key_t key2)
     61 {
     62 	char *keyp1 = (char*)key1;
     63 	char *keyp2 = (char*)key2;
     64 	return strcmp(keyp1, keyp2);
     65 }
     66 
     67 char *cil_strpool_add(const char *str)
     68 {
     69 	struct cil_strpool_entry *strpool_ref = NULL;
     70 
     71 	strpool_ref = hashtab_search(cil_strpool_tab, (hashtab_key_t)str);
     72 	if (strpool_ref == NULL) {
     73 		strpool_ref = cil_malloc(sizeof(*strpool_ref));
     74 		strpool_ref->str = cil_strdup(str);
     75 		int rc = hashtab_insert(cil_strpool_tab, (hashtab_key_t)strpool_ref->str, strpool_ref);
     76 		if (rc != SEPOL_OK) {
     77 			(*cil_mem_error_handler)();
     78 		}
     79 	}
     80 
     81 	return strpool_ref->str;
     82 }
     83 
     84 static int cil_strpool_entry_destroy(hashtab_key_t k __attribute__ ((unused)), hashtab_datum_t d, void *args __attribute__ ((unused)))
     85 {
     86 	struct cil_strpool_entry *strpool_ref = (struct cil_strpool_entry*)d;
     87 	free(strpool_ref->str);
     88 	free(strpool_ref);
     89 	return SEPOL_OK;
     90 }
     91 
     92 void cil_strpool_init(void)
     93 {
     94 	cil_strpool_tab = hashtab_create(cil_strpool_hash, cil_strpool_compare, CIL_STRPOOL_TABLE_SIZE);
     95 	if (cil_strpool_tab == NULL) {
     96 		(*cil_mem_error_handler)();
     97 	}
     98 }
     99 
    100 void cil_strpool_destroy(void)
    101 {
    102 	hashtab_map(cil_strpool_tab, cil_strpool_entry_destroy, NULL);
    103 	hashtab_destroy(cil_strpool_tab);
    104 }
    105