freebsd-dev/lib/libpthread/thread/thr_spec.c
Daniel Eischen 3003bdb598 Add the ability to recognize old references to keys, and return NULL
when old keys are referenced (after pthread_key_delete()) via
pthread_getspecific().
2002-03-19 22:58:56 +00:00

226 lines
6.1 KiB
C

/*
* Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``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 THE AUTHOR 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.
*
* $FreeBSD$
*/
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <pthread.h>
#include "pthread_private.h"
struct pthread_key {
spinlock_t lock;
volatile int allocated;
volatile int count;
int seqno;
void (*destructor) ();
};
/* Static variables: */
static struct pthread_key key_table[PTHREAD_KEYS_MAX];
__weak_reference(_pthread_key_create, pthread_key_create);
__weak_reference(_pthread_key_delete, pthread_key_delete);
__weak_reference(_pthread_getspecific, pthread_getspecific);
__weak_reference(_pthread_setspecific, pthread_setspecific);
int
_pthread_key_create(pthread_key_t * key, void (*destructor) (void *))
{
for ((*key) = 0; (*key) < PTHREAD_KEYS_MAX; (*key)++) {
/* Lock the key table entry: */
_SPINLOCK(&key_table[*key].lock);
if (key_table[(*key)].allocated == 0) {
key_table[(*key)].allocated = 1;
key_table[(*key)].destructor = destructor;
key_table[(*key)].seqno++;
/* Unlock the key table entry: */
_SPINUNLOCK(&key_table[*key].lock);
return (0);
}
/* Unlock the key table entry: */
_SPINUNLOCK(&key_table[*key].lock);
}
return (EAGAIN);
}
int
_pthread_key_delete(pthread_key_t key)
{
int ret = 0;
if (key < PTHREAD_KEYS_MAX) {
/* Lock the key table entry: */
_SPINLOCK(&key_table[key].lock);
if (key_table[key].allocated)
key_table[key].allocated = 0;
else
ret = EINVAL;
/* Unlock the key table entry: */
_SPINUNLOCK(&key_table[key].lock);
} else
ret = EINVAL;
return (ret);
}
void
_thread_cleanupspecific(void)
{
struct pthread *curthread = _get_curthread();
void *data = NULL;
int key;
int itr;
void (*destructor)( void *);
for (itr = 0; itr < PTHREAD_DESTRUCTOR_ITERATIONS; itr++) {
for (key = 0; key < PTHREAD_KEYS_MAX; key++) {
if (curthread->specific_data_count > 0) {
/* Lock the key table entry: */
_SPINLOCK(&key_table[key].lock);
destructor = NULL;
if (key_table[key].allocated &&
(curthread->specific[key].data != NULL)) {
if (curthread->specific[key].seqno ==
key_table[key].seqno) {
data = (void *) curthread->specific[key].data;
destructor = key_table[key].destructor;
}
curthread->specific[key].data = NULL;
curthread->specific_data_count--;
}
/* Unlock the key table entry: */
_SPINUNLOCK(&key_table[key].lock);
/*
* If there is a destructore, call it
* with the key table entry unlocked:
*/
if (destructor)
destructor(data);
} else {
free(curthread->specific);
curthread->specific = NULL;
return;
}
}
}
if (curthread->specific != NULL) {
free(curthread->specific);
curthread->specific = NULL;
}
}
static inline struct pthread_specific_elem *
pthread_key_allocate_data(void)
{
struct pthread_specific_elem *new_data;
new_data = (struct pthread_specific_elem *)
malloc(sizeof(struct pthread_specific_elem) * PTHREAD_KEYS_MAX);
if (new_data != NULL) {
memset((void *) new_data, 0,
sizeof(struct pthread_specific_elem) * PTHREAD_KEYS_MAX);
}
return (new_data);
}
int
_pthread_setspecific(pthread_key_t key, const void *value)
{
struct pthread *pthread;
int ret = 0;
/* Point to the running thread: */
pthread = _get_curthread();
if ((pthread->specific) ||
(pthread->specific = pthread_key_allocate_data())) {
if (key < PTHREAD_KEYS_MAX) {
if (key_table[key].allocated) {
if (pthread->specific[key].data == NULL) {
if (value != NULL)
pthread->specific_data_count++;
} else {
if (value == NULL)
pthread->specific_data_count--;
}
pthread->specific[key].data = value;
pthread->specific[key].seqno =
key_table[key].seqno;
ret = 0;
} else
ret = EINVAL;
} else
ret = EINVAL;
} else
ret = ENOMEM;
return (ret);
}
void *
_pthread_getspecific(pthread_key_t key)
{
struct pthread *pthread;
void *data;
/* Point to the running thread: */
pthread = _get_curthread();
/* Check if there is specific data: */
if (pthread->specific != NULL && key < PTHREAD_KEYS_MAX) {
/* Check if this key has been used before: */
if (key_table[key].allocated &&
(pthread->specific[key].seqno == key_table[key].seqno)) {
/* Return the value: */
data = (void *) pthread->specific[key].data;
} else {
/*
* This key has not been used before, so return NULL
* instead:
*/
data = NULL;
}
} else
/* No specific data has been created, so just return NULL: */
data = NULL;
return (data);
}