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140 lines
4.8 KiB
140 lines
4.8 KiB
/**************************************************************************** |
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* sched/sem_unlink.c |
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* |
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* Copyright (C) 2007-2009 Gregory Nutt. All rights reserved. |
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* Author: Gregory Nutt <gnutt@nuttx.org> |
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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 NuttX 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 <nuttx/config.h> |
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#include <stdbool.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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* Pre-processor 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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* Name: sem_unlink |
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* |
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* Description: |
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* This function removes the semaphore named by the input parameter 'name.' |
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* If the semaphore named by 'name' is currently referenced by other task, |
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* the sem_unlink() will have no effect on the state of the semaphore. If |
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* one or more processes have the semaphore open when sem_unlink() is |
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* called, destruction of the semaphore will be postponed until all |
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* references to the semaphore 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(FAR 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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