143 lines
4.7 KiB
C
143 lines
4.7 KiB
C
/************************************************************
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* sem_unlink.c
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*
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* Copyright (C) 2007 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name Gregory Nutt nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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************************************************************/
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/************************************************************
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* Included Files
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************************************************************/
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#include <sys/types.h>
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#include <semaphore.h>
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#include <sched.h>
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#include <queue.h>
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#include "os_internal.h"
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#include "sem_internal.h"
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/************************************************************
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* Compilation Switches
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************************************************************/
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/************************************************************
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* Definitions
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************************************************************/
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/************************************************************
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* Private Type Declarations
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************************************************************/
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/************************************************************
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* Global Variables
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************************************************************/
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/************************************************************
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* Private Variables
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************************************************************/
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/************************************************************
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* Private Functions
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************************************************************/
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/************************************************************
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* Public Functions
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************************************************************/
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/************************************************************
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* Function: sem_unlink
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*
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* Description:
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* This function removes the semaphore named by the input
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* parameter "name." If the semaphore named by "name" is
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* currently referenced by other processes, the sem_unlink()
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* will have no effect on the state of the semaphore. If
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* one or more processes have the semaphore open when
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* sem_unlink() is called, destruction of the semaphore
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* will be postponed until all references to the semaphore
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* have been destroyed by calls of sem_close().
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*
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* Parameters:
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* name - Semaphore name
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*
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* Return Value:
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* 0 (OK), or -1 (ERROR) if unsuccessful.
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*
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* Assumptions:
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*
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************************************************************/
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int sem_unlink(const char *name)
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{
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FAR nsem_t *psem;
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int ret = ERROR;
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/* Verify the input values */
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if (name)
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{
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sched_lock();
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/* Find the named semaphore */
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psem = sem_findnamed(name);
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/* Check if the semaphore was found */
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if (psem)
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{
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/* If the named semaphore was found and if there are no
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* connects to it, then deallocate it
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*/
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if (!psem->nconnect)
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{
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dq_rem((FAR dq_entry_t*)psem, &g_nsems);
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sched_free(psem);
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}
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/* If one or more process still has the semaphore open,
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* then just mark it as unlinked. The unlinked semaphore will
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* be deleted when the final process closes the semaphore.
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*/
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else
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{
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psem->unlinked = TRUE;
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}
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ret = OK;
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}
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sched_unlock();
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}
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return ret;
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}
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