/*

 * Copyright 2014 Tresys Technology, LLC. All rights reserved.

 * 

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 * 

 *    1. Redistributions of source code must retain the above copyright notice,

 *       this list of conditions and the following disclaimer.

 * 

 *    2. Redistributions in binary form must reproduce the above copyright notice,

 *       this list of conditions and the following disclaimer in the documentation

 *       and/or other materials provided with the distribution.

 * 

 * THIS SOFTWARE IS PROVIDED BY TRESYS TECHNOLOGY, LLC ``AS IS'' AND ANY EXPRESS

 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO

 * EVENT SHALL TRESYS TECHNOLOGY, LLC OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,

 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,

 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE

 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF

 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 * 

 * The views and conclusions contained in the software and documentation are those

 * of the authors and should not be interpreted as representing official policies,

 * either expressed or implied, of Tresys Technology, LLC.

 */

#include <pthread.h>

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include "cil_mem.h"

#include "cil_strpool.h"

#include "cil_log.h"

#define CIL_STRPOOL_TABLE_SIZE 1 << 15

struct cil_strpool_entry {

  char *str;

};

static pthread_mutex_t cil_strpool_mutex = PTHREAD_MUTEX_INITIALIZER;

static unsigned int cil_strpool_readers = 0;

static hashtab_t cil_strpool_tab = NULL;

static unsigned int cil_strpool_hash(hashtab_t h, const_hashtab_key_t key)

{

  unsigned int hash = 5381;

  unsigned char c;

  while ((c = *(unsigned const char *)key++))

    hash = ((hash << 5) + hash) ^ c;

  return hash & (h->size - 1);

}

static int cil_strpool_compare(hashtab_t h __attribute__((unused)),

             const_hashtab_key_t key1,

             const_hashtab_key_t key2)

{

  return strcmp(key1, key2);

}

char *cil_strpool_add(const char *str)

{

  struct cil_strpool_entry *strpool_ref = NULL;

  pthread_mutex_lock(&cil_strpool_mutex);

  strpool_ref = hashtab_search(cil_strpool_tab, str);

  if (strpool_ref == NULL) {

    int rc;

    strpool_ref = cil_malloc(sizeof(*strpool_ref));

    strpool_ref->str = cil_strdup(str);

    rc = hashtab_insert(cil_strpool_tab, strpool_ref->str,

            strpool_ref);

    if (rc != SEPOL_OK) {

      pthread_mutex_unlock(&cil_strpool_mutex);

      cil_log(CIL_ERR, "Failed to allocate memory\n");

      exit(1);

    }

  }

  pthread_mutex_unlock(&cil_strpool_mutex);

  return strpool_ref->str;

}

static int cil_strpool_entry_destroy(hashtab_key_t k __attribute__((unused)),

             hashtab_datum_t d,

             void *args __attribute__((unused)))

{

  struct cil_strpool_entry *strpool_ref = (struct cil_strpool_entry *)d;

  free(strpool_ref->str);

  free(strpool_ref);

  return SEPOL_OK;

}

void cil_strpool_init(void)

{

  pthread_mutex_lock(&cil_strpool_mutex);

  if (cil_strpool_tab == NULL) {

    cil_strpool_tab = hashtab_create(cil_strpool_hash,

             cil_strpool_compare,

             CIL_STRPOOL_TABLE_SIZE);

    if (cil_strpool_tab == NULL) {

      pthread_mutex_unlock(&cil_strpool_mutex);

      cil_log(CIL_ERR, "Failed to allocate memory\n");

      exit(1);

    }

  }

  cil_strpool_readers++;

  pthread_mutex_unlock(&cil_strpool_mutex);

}

void cil_strpool_destroy(void)

{

  pthread_mutex_lock(&cil_strpool_mutex);

  cil_strpool_readers--;

  if (cil_strpool_readers == 0) {

    hashtab_map(cil_strpool_tab, cil_strpool_entry_destroy, NULL);

    hashtab_destroy(cil_strpool_tab);

    cil_strpool_tab = NULL;

  }

  pthread_mutex_unlock(&cil_strpool_mutex);

}