From 1f49e6a8633f08849340621f9fd36ecfe6d56f2c Mon Sep 17 00:00:00 2001 From: stefan Date: Sun, 22 Aug 2010 09:51:57 +0000 Subject: [PATCH] - 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 --- fs/null.c | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 106 insertions(+) create mode 100644 fs/null.c diff --git a/fs/null.c b/fs/null.c new file mode 100644 index 00000000..4fa0d840 --- /dev/null +++ b/fs/null.c @@ -0,0 +1,106 @@ +/* + * Copyright 2010 Stefan Lankes, Chair for Operating Systems, + * RWTH Aachen University + * + * Licensed 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. + * + * This file is part of MetalSVM. + */ + +#include +#include +#include +#include +#include + +/* Implementation of a simple null device */ + +static ssize_t null_read(vfs_node_t* node, uint8_t* buffer, size_t size, off_t offset) +{ + memset(buffer, 0x00, size); + + return size; +} + +static ssize_t null_write(vfs_node_t* node, uint8_t* buffer, size_t size, off_t offset) +{ + return size; +} + +static int null_open(vfs_node_t* node) +{ + return 0; +} + +static int null_close(vfs_node_t* node) +{ + return 0; +} + +int null_init(vfs_node_t* node, const char* name) +{ + uint32_t i, j; + vfs_node_t* new_node; + dir_block_t* blockdir; + dirent_t* dirent; + block_list_t* blist; + + if (BUILTIN_EXPECT(!node || !name, 0)) + return -EINVAL; + + if (BUILTIN_EXPECT(node->type != FS_DIRECTORY, 0)) + return -EINVAL; + + if (finddir_fs(node, name)) + return -EINVAL; + + new_node = kmalloc(sizeof(vfs_node_t)); + if (BUILTIN_EXPECT(!new_node, 0)) + return -ENOMEM; + + memset(new_node, 0x00, sizeof(vfs_node_t)); + new_node->type = FS_CHARDEVICE; + new_node->open = &null_open; + new_node->close = &null_close; + new_node->read = &null_read; + new_node->write = &null_write; + spinlock_init(&new_node->lock); + + blist= &node->block_list; + do { + for(i=0; idata[i]) { + blockdir = (dir_block_t*) blist->data[i]; + for(j=0; jentries[j]; + if (!dirent->vfs_node) { + dirent->vfs_node = new_node; + strncpy(dirent->name, name, MAX_FNAME); + return 0; + } + } + } + } + + if (!blist->next) { + blist->next = (block_list_t*) kmalloc(sizeof(block_list_t)); + if (blist->next) + memset(blist->next, 0x00, sizeof(block_list_t)); + } + + } while(blist); + + kfree(new_node, sizeof(vfs_node_t)); + + return -ENOMEM; +}