150 lines
6.4 KiB
C
150 lines
6.4 KiB
C
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/****************************************************************************
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* mm/shm/shmget.c
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*
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* Copyright (C) 2014 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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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/shm.h>
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#include <sys/ipc.h>
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#include <errno.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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/****************************************************************************
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* Private Types
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****************************************************************************/
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: shmget
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*
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* Description:
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* The shmget() function will return the shared memory identifier
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* associated with key.
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*
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* A shared memory identifier, associated data structure, and shared
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* memory segment of at least size bytes is created for key if one of the
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* following is true:
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*
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* - The argument key is equal to IPC_PRIVATE.
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* - The argument key does not already have a shared memory identifier
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* associated with it and (shmflg & IPC_CREAT) is non-zero.
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*
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* Upon creation, the data structure associated with the new shared memory
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* identifier will be initialized as follows:
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*
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* - The values of shm_perm.cuid, shm_perm.uid, shm_perm.cgid, and
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* shm_perm.gid are set equal to the effective user ID and effective
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* group ID, respectively, of the calling process.
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* - The low-order nine bits of shm_perm.mode are set equal to the low-
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* order nine bits of shmflg.
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* - The value of shm_segsz is set equal to the value of size.
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* - The values of shm_lpid, shm_nattch, shm_atime, and shm_dtime are
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* set equal to 0.
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* - The value of shm_ctime is set equal to the current time.
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*
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* When the shared memory segment is created, it will be initialized with
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* all zero values.
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*
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* Input Parameters:
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* key - The key that is used to access the unique shared memory
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* identifier.
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* size - The shared memory region that is created will be at least
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* this size in bytes.
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* shmflgs - See IPC_* definitions in sys/ipc.h. Only the values
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* IPC_PRIVATE or IPC_CREAT are supported.
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*
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* Returned Value:
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* Upon successful completion, shmget() will return a non-negative
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* integer, namely a shared memory identifier; otherwise, it will return
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* -1 and set errno to indicate the error.
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*
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* - EACCES
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* A shared memory identifier exists for key but operation permission
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* as specified by the low-order nine bits of shmflg would not be
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* granted.
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* - EEXIST
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* A shared memory identifier exists for the argument key but
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* (shmflg & IPC_CREAT) && (shmflg & IPC_EXCL) are non-zero.
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* - EINVAL
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* A shared memory segment is to be created and the value of size is
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* less than the system-imposed minimum or greater than the system-
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* imposed maximum.
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* - EINVAL
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* No shared memory segment is to be created and a shared memory
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* segment exists for key but the size of the segment associated with
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* it is less than size and size is not 0.
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* - ENOENT
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* A shared memory identifier does not exist for the argument key and
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* (shmflg & IPC_CREAT) is 0.
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* - ENOMEM
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* A shared memory identifier and associated shared memory segment
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* will be created, but the amount of available physical memory is
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* not sufficient to fill the request.
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* - ENOSPC
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* A shared memory identifier is to be created, but the system-imposed
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* limit on the maximum number of allowed shared memory identifiers
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* system-wide would be exceeded.
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*
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****************************************************************************/
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int shmget(key_t key, size_t size, int shmflg)
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{
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#warning Not implemented
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set_errno(ENOSYS);
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return ERROR;
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}
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#endif /* CONFIG_MM_SHM */
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