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 <pthread.h> 31 #include <stdlib.h> 32 #include <stdio.h> 33 #include <string.h> 34 #include "cil_mem.h" 35 #include "cil_strpool.h" 36 37 #include "cil_log.h" 38 #define CIL_STRPOOL_TABLE_SIZE 1 << 15 39 40 struct cil_strpool_entry { 41 char *str; 42 }; 43 44 static pthread_mutex_t cil_strpool_mutex = PTHREAD_MUTEX_INITIALIZER; 45 static unsigned int cil_strpool_readers = 0; 46 static hashtab_t cil_strpool_tab = NULL; 47 48 static unsigned int cil_strpool_hash(hashtab_t h, const_hashtab_key_t key) 49 { 50 const char *p, *keyp; 51 size_t size; 52 unsigned int val; 53 54 val = 0; 55 keyp = (const char*)key; 56 size = strlen(keyp); 57 for (p = keyp; ((size_t) (p - keyp)) < size; p++) 58 val = 59 (val << 4 | (val >> (8 * sizeof(unsigned int) - 4))) ^ (*p); 60 return val & (h->size - 1); 61 } 62 63 static int cil_strpool_compare(hashtab_t h __attribute__ ((unused)), const_hashtab_key_t key1, const_hashtab_key_t key2) 64 { 65 const char *keyp1 = (const char*)key1; 66 const char *keyp2 = (const char*)key2; 67 return strcmp(keyp1, keyp2); 68 } 69 70 char *cil_strpool_add(const char *str) 71 { 72 struct cil_strpool_entry *strpool_ref = NULL; 73 74 pthread_mutex_lock(&cil_strpool_mutex); 75 76 strpool_ref = hashtab_search(cil_strpool_tab, (hashtab_key_t)str); 77 if (strpool_ref == NULL) { 78 strpool_ref = cil_malloc(sizeof(*strpool_ref)); 79 strpool_ref->str = cil_strdup(str); 80 int rc = hashtab_insert(cil_strpool_tab, (hashtab_key_t)strpool_ref->str, strpool_ref); 81 if (rc != SEPOL_OK) { 82 pthread_mutex_unlock(&cil_strpool_mutex); 83 (*cil_mem_error_handler)(); 84 pthread_mutex_lock(&cil_strpool_mutex); 85 } 86 } 87 88 pthread_mutex_unlock(&cil_strpool_mutex); 89 return strpool_ref->str; 90 } 91 92 static int cil_strpool_entry_destroy(hashtab_key_t k __attribute__ ((unused)), hashtab_datum_t d, void *args __attribute__ ((unused))) 93 { 94 struct cil_strpool_entry *strpool_ref = (struct cil_strpool_entry*)d; 95 free(strpool_ref->str); 96 free(strpool_ref); 97 return SEPOL_OK; 98 } 99 100 void cil_strpool_init(void) 101 { 102 pthread_mutex_lock(&cil_strpool_mutex); 103 if (cil_strpool_tab == NULL) { 104 cil_strpool_tab = hashtab_create(cil_strpool_hash, cil_strpool_compare, CIL_STRPOOL_TABLE_SIZE); 105 if (cil_strpool_tab == NULL) { 106 pthread_mutex_unlock(&cil_strpool_mutex); 107 (*cil_mem_error_handler)(); 108 return; 109 } 110 } 111 cil_strpool_readers++; 112 pthread_mutex_unlock(&cil_strpool_mutex); 113 } 114 115 void cil_strpool_destroy(void) 116 { 117 pthread_mutex_lock(&cil_strpool_mutex); 118 cil_strpool_readers--; 119 if (cil_strpool_readers == 0) { 120 hashtab_map(cil_strpool_tab, cil_strpool_entry_destroy, NULL); 121 hashtab_destroy(cil_strpool_tab); 122 } 123 pthread_mutex_unlock(&cil_strpool_mutex); 124 } 125