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- /****************************************************************************
- * mm/shm/shm.h
- *
- * Copyright (C) 2014 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
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
- * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- *
- ****************************************************************************/
- #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 <semaphore.h>
- #include <nuttx/addrenv.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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