/****************************************************************************
* sched/sem_unlink.c
*
* Copyright (C) 2007-2009 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
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* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdbool.h>
#include <semaphore.h>
#include <sched.h>
#include <queue.h>
#include "os_internal.h"
#include "sem_internal.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: sem_unlink
*
* Description:
* This function removes the semaphore named by the input parameter 'name.'
* If the semaphore named by 'name' is currently referenced by other task,
* the sem_unlink() will have no effect on the state of the semaphore. If
* one or more processes have the semaphore open when sem_unlink() is
* called, destruction of the semaphore will be postponed until all
* references to the semaphore have been destroyed by calls of sem_close().
*
* Parameters:
* name - Semaphore name
*
* Return Value:
* 0 (OK), or -1 (ERROR) if unsuccessful.
*
* Assumptions:
*
****************************************************************************/
int sem_unlink(FAR const char *name)
{
FAR nsem_t *psem;
int ret = ERROR;
/* Verify the input values */
if (name)
{
sched_lock();
/* Find the named semaphore */
psem = sem_findnamed(name);
/* Check if the semaphore was found */
if (psem)
{
/* If the named semaphore was found and if there are no
* connects to it, then deallocate it
*/
if (!psem->nconnect)
{
dq_rem((FAR dq_entry_t*)psem, &g_nsems);
sched_kfree(psem);
}
/* If one or more process still has the semaphore open,
* then just mark it as unlinked. The unlinked semaphore will
* be deleted when the final process closes the semaphore.
*/
else
{
psem->unlinked = true;
}
ret = OK;
}
sched_unlock();
}
return ret;
}
