- add a simple implementation of a null device
git-svn-id: http://svn.lfbs.rwth-aachen.de/svn/scc/trunk/MetalSVM@117 315a16e6-25f9-4109-90ae-ca3045a26c18
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106
fs/null.c
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106
fs/null.c
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/*
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* Copyright 2010 Stefan Lankes, Chair for Operating Systems,
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* RWTH Aachen University
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* 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,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* This file is part of MetalSVM.
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*/
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#include <metalsvm/stdlib.h>
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#include <metalsvm/string.h>
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#include <metalsvm/stdio.h>
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#include <metalsvm/errno.h>
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#include <metalsvm/fs.h>
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/* Implementation of a simple null device */
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static ssize_t null_read(vfs_node_t* node, uint8_t* buffer, size_t size, off_t offset)
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{
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memset(buffer, 0x00, size);
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return size;
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}
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static ssize_t null_write(vfs_node_t* node, uint8_t* buffer, size_t size, off_t offset)
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{
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return size;
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}
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static int null_open(vfs_node_t* node)
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{
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return 0;
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}
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static int null_close(vfs_node_t* node)
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{
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return 0;
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}
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int null_init(vfs_node_t* node, const char* name)
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{
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uint32_t i, j;
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vfs_node_t* new_node;
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dir_block_t* blockdir;
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dirent_t* dirent;
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block_list_t* blist;
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if (BUILTIN_EXPECT(!node || !name, 0))
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return -EINVAL;
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if (BUILTIN_EXPECT(node->type != FS_DIRECTORY, 0))
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return -EINVAL;
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if (finddir_fs(node, name))
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return -EINVAL;
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new_node = kmalloc(sizeof(vfs_node_t));
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if (BUILTIN_EXPECT(!new_node, 0))
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return -ENOMEM;
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memset(new_node, 0x00, sizeof(vfs_node_t));
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new_node->type = FS_CHARDEVICE;
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new_node->open = &null_open;
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new_node->close = &null_close;
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new_node->read = &null_read;
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new_node->write = &null_write;
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spinlock_init(&new_node->lock);
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blist= &node->block_list;
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do {
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for(i=0; i<MAX_DATABLOCKS; i++) {
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if (blist->data[i]) {
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blockdir = (dir_block_t*) blist->data[i];
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for(j=0; j<MAX_DIRENTRIES; j++) {
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dirent = &blockdir->entries[j];
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if (!dirent->vfs_node) {
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dirent->vfs_node = new_node;
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strncpy(dirent->name, name, MAX_FNAME);
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return 0;
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}
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}
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}
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}
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if (!blist->next) {
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blist->next = (block_list_t*) kmalloc(sizeof(block_list_t));
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if (blist->next)
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memset(blist->next, 0x00, sizeof(block_list_t));
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}
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} while(blist);
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kfree(new_node, sizeof(vfs_node_t));
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return -ENOMEM;
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}
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