incubator-nuttx/sched/pthread/pthread_keycreate.c

141 lines
5.0 KiB
C

/****************************************************************************
* sched/pthread/pthread_keycreate.c
*
* Copyright (C) 2007-2009, 2013, 2018 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
* COPYRIGHT OWNER 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sched.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/irq.h>
#include "sched/sched.h"
#include "pthread/pthread.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: pthread_key_create
*
* Description:
* This function creates a thread-specific data key visible to all threads
* in the system. Although the same key value may be used by different
* threads, the values bound to the key by pthread_setspecific() are
* maintained on a per-thread basis and persist for the life of the calling
* thread.
*
* Upon key creation, the value NULL will be associated with the new key
* in all active threads. Upon thread creation, the value NULL will be
* associated with all defined keys in the new thread.
*
* Input Parameters:
* key - A pointer to the key to create.
* destructor - An optional destructor() function that may be associated
* with each key that is invoked when a thread exits.
* However, this argument is ignored in the current
* implementation.
*
* Returned Value:
* If successful, the pthread_key_create() function will store the newly
* created key value at *key and return zero (OK). Otherwise, an error
* number will be returned to indicate the error:
*
* EAGAIN - The system lacked sufficient resources to create another
* thread-specific data key, or the system-imposed limit on
* the total number of keys pers process {PTHREAD_KEYS_MAX}
* has been exceeded
* ENONMEM - Insufficient memory exists to create the key.
*
* POSIX Compatibility:
* - The present implementation ignores the destructor argument.
*
****************************************************************************/
int pthread_key_create(FAR pthread_key_t *key,
CODE void (*destructor)(FAR void *))
{
#if CONFIG_NPTHREAD_KEYS > 0
FAR struct tcb_s *rtcb = this_task();
FAR struct task_group_s *group = rtcb->group;
irqstate_t flags;
int candidate;
int ret = EAGAIN;
DEBUGASSERT(key != NULL && group != NULL);
/* Search for an unused key. This is done in a critical section here to
* avoid concurrent modification of the group keyset.
*/
flags = spin_lock_irqsave();
for (candidate = 0; candidate < PTHREAD_KEYS_MAX; candidate++)
{
/* Is this candidate key available? */
pthread_keyset_t mask = (1 << candidate);
if ((group->tg_keyset & mask) == 0)
{
/* Yes.. allocate the key and break out of the loop */
group->tg_keyset |= mask;
break;
}
}
spin_unlock_irqrestore(flags);
/* Check if found a valid key. */
if (candidate < PTHREAD_KEYS_MAX)
{
/* Yes.. Return the key value and success */
*key = candidate;
ret = OK;
}
return ret;
#else
return ENOSYS;
#endif
}