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/****************************************************************************
* mm/shm/shmat.c
*
* 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/shm.h>
#include <errno.h>
#ifdef CONFIG_MM_SHM
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: shmat
*
* Description:
* The shmat() function attaches the shared memory segment associated with
* the shared memory identifier specified by shmid to the address space of
* the calling process. The segment is attached at the address specified
* by one of the following criteria:
*
* - If shmaddr is a null pointer, the segment is attached at the first
* available address as selected by the system.
* - If shmaddr is not a null pointer and (shmflg & SHM_RND) is non-
* zero, the segment is attached at the address given by
* (shmaddr - ((uintptr_t)shmaddr % SHMLBA)).
* - If shmaddr is not a null pointer and (shmflg & SHM_RND) is 0, the
* segment is attached at the address given by shmaddr.
* - The segment is attached for reading if (shmflg & SHM_RDONLY) is
* non-zero and the calling process has read permission; otherwise, if
* it is 0 and the calling process has read and write permission, the
* segment is attached for reading and writing.
*
* Input Parameters:
* shmid - Shared memory identifier
* smaddr - Determines mapping of the shared memory region
* shmflg - See SHM_* definitions in include/sys/shm.h. Only SHM_RDONLY
* and SHM_RND are supported.
*
* Returned Value:
* Upon successful completion, shmat() will increment the value of
* shm_nattch in the data structure associated with the shared memory ID
* of the attached shared memory segment and return the segment's start address.
*
* Otherwise, the shared memory segment will not be attached, shmat() will
* return -1, and errno will be set to indicate the error.
*
* - EACCES
* Operation permission is denied to the calling process
* - EINVAL
* The value of shmid is not a valid shared memory identifier, the
* shmaddr is not a null pointer, and the value of
* (shmaddr -((uintptr_t)shmaddr % SHMLBA)) is an illegal address for
* attaching shared memory; or the shmaddr is not a null pointer,
* (shmflg & SHM_RND) is 0, and the value of shmaddr is an illegal
* address for attaching shared memory.
* - EMFILE
* The number of shared memory segments attached to the calling
* process would exceed the system-imposed limit.
* - ENOMEM
* The available data space is not large enough to accommodate the
* shared memory segment.
*
****************************************************************************/
FAR void *shmat(int shmid, FAR const void *shmaddr, int shmflg)
{
#warning Not implemented
set_errno(ENOSYS);
return (FAR void *)ERROR;
}
#endif /* CONFIG_MM_SHM */
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