a0ebddaac1
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>
163 lines
3.9 KiB
C
163 lines
3.9 KiB
C
/****************************************************************************
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* fs/shm/shm_unlink.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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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 <stdio.h>
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#include <assert.h>
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#include <errno.h>
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#include "inode/inode.h"
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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static int file_shm_unlink(FAR const char *name)
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{
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FAR struct inode *inode;
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struct inode_search_s desc;
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char fullpath[sizeof(CONFIG_FS_SHMFS_VFS_PATH) + CONFIG_NAME_MAX + 2];
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int ret;
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/* Make sure that a non-NULL name is supplied */
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if (!name)
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{
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return -ENOENT;
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}
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/* Remove any number of leading '/' */
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while (*name == '/')
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{
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name++;
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}
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/* Empty name supplied? */
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if (*name == '\0')
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{
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return -ENOENT;
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}
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/* Name too long? */
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if (strnlen(name, CONFIG_NAME_MAX + 1) > CONFIG_NAME_MAX)
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{
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return -ENAMETOOLONG;
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}
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/* Get the full path to the shm object */
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snprintf(fullpath, sizeof(fullpath),
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CONFIG_FS_SHMFS_VFS_PATH "/%s", name);
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/* Get the inode for this shm object */
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SETUP_SEARCH(&desc, fullpath, false);
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ret = inode_lock();
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if (ret < 0)
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{
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goto errout_with_search;
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}
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ret = inode_find(&desc);
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if (ret < 0)
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{
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/* There is no inode that includes in this path */
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goto errout_with_sem;
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}
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/* Get the search results */
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inode = desc.node;
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DEBUGASSERT(inode != NULL);
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/* Verify that what we found is, indeed, an shm inode */
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if (!INODE_IS_SHM(inode))
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{
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ret = -ENOENT;
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goto errout_with_inode;
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}
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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if (inode->u.i_ops->unlink)
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{
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/* Notify the shmfs driver that it has been unlinked */
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ret = inode->u.i_ops->unlink(inode);
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if (ret < 0)
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{
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goto errout_with_inode;
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}
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}
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#endif
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/* Remove the old inode from the tree. If we hold a reference count
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* on the inode, it will not be deleted now. This will set the
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* FSNODEFLAG_DELETED bit in the inode flags.
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*/
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ret = inode_remove(fullpath);
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/* inode_remove() should always fail with -EBUSY because we have a
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* reference on the inode. -EBUSY means that the inode was, indeed,
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* unlinked but it could not be freed because there are references.
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*/
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if (ret == -EBUSY)
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{
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ret = OK;
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}
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DEBUGASSERT(ret == OK);
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errout_with_inode:
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inode_release(inode);
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errout_with_sem:
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inode_unlock();
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errout_with_search:
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RELEASE_SEARCH(&desc);
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return ret;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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int shm_unlink(FAR const char *name)
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{
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int ret = file_shm_unlink(name);
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if (ret < 0)
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{
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set_errno(-ret);
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return -1;
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}
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return 0;
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}
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