nuttx/fs/shm/shmfs.h
Jukka Laitinen a0ebddaac1 fs/shm: Add initial implementation for posix shared memory
This implements the file system logic for posix shared memory:
shm_open, shm_unlink, mmap, munmap and close

For flat and protected builds the memory simply allocated from (user) heap

For kernel build the memory is allocated from page pool and mapped with MMU

This doesn't yet support protection flags or re-sizing already truncated shared
memory area.

Co-authored-by: Ville Juven <ville.juven@unikie.com>
Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>
2023-01-18 11:01:20 +08:00

71 lines
2.4 KiB
C

/****************************************************************************
* fs/shm/shmfs.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 __FS_SHM_SHMFS_H
#define __FS_SHM_SHMFS_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/fs/fs.h>
/****************************************************************************
* Public Data
****************************************************************************/
extern const struct file_operations shmfs_operations;
/****************************************************************************
* Public Types
****************************************************************************/
struct shmfs_object_s
{
/* Total number of bytes needed from physical memory. */
size_t length;
/* Vector of allocations from physical memory.
*
* - In flat and protected builds this is a pointer to the
* allocated memory.
*
* - In kernel build this is start of a malloc'd vector of void pointers
* and the length of the vector is MM_NPAGES(length).
*/
FAR void *paddr;
/* The struct continues here as malloc'd array of void pointers
* if CONFIG_BUILD_KERNEL
*/
};
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
FAR struct shmfs_object_s *shmfs_alloc_object(size_t length);
void shmfs_free_object(FAR struct shmfs_object_s *object);
#endif