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