source: trunk/sys/libpthread/pthread_keys.c@ 17

/*
 * pthread_keys.c -  pthread specific keys related functions
 * 
 * Copyright (c) 2008,2009,2010,2011,2012 Ghassan Almaless
 * Copyright (c) 2011,2012 UPMC Sorbonne Universites
 *
 * This file is part of ALMOS.
 *
 * ALMOS is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2.0 of the License.
 *
 * ALMOS is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with ALMOS; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <sys/types.h>
#include <errno.h>
#include <string.h>
#include <cpu-syscall.h>
#include <pthread.h>
#include <stdio.h>

#define KEY_FREE 0
#define KEY_BUSY 1

typedef void (key_destr_func_t)(void*);

typedef struct key_entry_s
{
        int state;
        key_destr_func_t *destructor;
}key_entry_t;

static pthread_spinlock_t lock;
static key_entry_t keys_tbl[PTHREAD_KEYS_MAX];
static unsigned long next_key;

void __pthread_keys_init(void)
{
        key_entry_t *ptr = &keys_tbl[0];
        memset(ptr, 0, sizeof(keys_tbl));
        next_key = 0;
        pthread_spin_init(&lock, 0);
}

void __pthread_keys_destroy(void)
{
        __pthread_tls_t *tls;
        int iter, key;
        void *old_val;
        int hasVal, err;

        tls = cpu_get_tls();
 
        for(iter=0; iter < PTHREAD_DESTRUCTOR_ITERATIONS; iter++)
        {
                for(key=0, hasVal = 0; key < PTHREAD_KEYS_MAX; key++)
                {
                        if(tls->values_tbl[key] == NULL)
                                continue;
      
                        old_val = tls->values_tbl[key];
                        tls->values_tbl[key] = NULL;

                        if((old_val == NULL) || (keys_tbl[key].destructor == NULL))
                                continue;
      
                        keys_tbl[key].destructor(old_val);
                        hasVal = 1;
                }

                if(!hasVal) return;
        }
}

int pthread_key_create(pthread_key_t *key, void (*destructor)(void*))
{
        int _key;
        int err;
  
        if(key == NULL)
                return EINVAL;
  
        err = 0;

        pthread_spin_lock(&lock);
  
        for(_key=next_key; (keys_tbl[_key].state != KEY_FREE) && (_key < PTHREAD_KEYS_MAX); _key++);
  
        if(_key != PTHREAD_KEYS_MAX)
        {
                keys_tbl[_key].state = KEY_BUSY;
                next_key = _key + 1;    
        }
        else
                err = EAGAIN;
  
        pthread_spin_unlock(&lock);
  
        if(err) return err;
  
        keys_tbl[_key].destructor = destructor;
        *key = _key;
        return 0;
}

int pthread_key_delete(pthread_key_t key)
{  
        if((key >= PTHREAD_KEYS_MAX) || (keys_tbl[key].state != KEY_BUSY))
                return EINVAL;
  
        keys_tbl[key].state = KEY_FREE;

        if(key < next_key)
        {
                pthread_spin_lock(&lock);
                next_key = (key < next_key) ? key : next_key;
                pthread_spin_unlock(&lock); 
        }

        return 0;
}

int pthread_setspecific(pthread_key_t key, const void *value)
{
        __pthread_tls_t *tls;

        if((key >= PTHREAD_KEYS_MAX) || (keys_tbl[key].state != KEY_BUSY))
                return EINVAL;

        tls = cpu_get_tls();
        tls->values_tbl[key] = (void*)value;

        return 0;
}

void *pthread_getspecific(pthread_key_t key)
{
        __pthread_tls_t *tls;

        if((key >= PTHREAD_KEYS_MAX) || (keys_tbl[key].state != KEY_BUSY))
                return NULL;

        tls = cpu_get_tls();
        return tls->values_tbl[key];
}