120 lines
4.1 KiB
C
120 lines
4.1 KiB
C
/****************************************************************************
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* mm/shm/shm.h
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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#ifndef __MM_SHM_SHM_H
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#define __MM_SHM_SHM_H
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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 <sys/ipc.h>
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#include <sys/shm.h>
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#include <stdint.h>
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#include <nuttx/addrenv.h>
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#include <nuttx/semaphore.h>
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#ifdef CONFIG_MM_SHM
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Bit definitions for the struct shm_region_s sr_flags field */
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#define SRFLAG_AVAILABLE 0 /* Available if no flag bits set */
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#define SRFLAG_INUSE (1 << 0) /* Bit 0: Region is in use */
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#define SRFLAG_UNLINKED (1 << 1) /* Bit 1: Region perists while references */
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/****************************************************************************
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* Public Types
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****************************************************************************/
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/* This structure represents the state of one shared memory region
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* allocation. Cast compatible with struct shmid_ds.
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*/
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struct shm_region_s
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{
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struct shmid_ds sr_ds; /* Region info */
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bool sr_flags; /* See SRFLAGS_* definitions */
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key_t sr_key; /* Lookup key */
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sem_t sr_sem; /* Manages exclusive access to this region */
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/* List of physical pages allocated for this memory region */
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uintptr_t sr_pages[CONFIG_ARCH_SHM_NPAGES];
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};
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/* This structure represents the set of all shared memory regions.
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* Access to the region
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*/
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struct shm_info_s
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{
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sem_t si_sem; /* Manages exclusive access to the region list */
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struct shm_region_s si_region[CONFIG_ARCH_SHM_MAXREGIONS];
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};
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/****************************************************************************
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* Public Data
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****************************************************************************/
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/* State of the all shared memory */
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extern struct shm_info_s g_shminfo;
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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/****************************************************************************
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* Name: shm_destroy
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*
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* Description:
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* Destroy a memory region. This function is called:
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*
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* - On certain conditions when shmget() is not successful in instantiating
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* the full memory region and we need to clean up and free a table entry.
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* - When shmctl() is called with cmd == IPC_RMID and there are no
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* processes attached to the memory region.
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* - When shmdt() is called after the last process detaches from memory
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* region after it was previously marked for deletion by shmctl().
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*
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* Input Parameters:
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* shmid - Shared memory identifier
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*
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* Returned Value:
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* None
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*
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* Assumption:
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* The caller holds either the region table semaphore or else the
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* semaphore on the particular entry being deleted.
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*
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****************************************************************************/
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void shm_destroy(int shmid);
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#endif /* CONFIG_MM_SHM */
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#endif /* __MM_SHM_SHM_H */
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