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2520 jermar 1 
/*
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 * Copyright (c) 2007 Jakub Jermar
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 * All rights reserved.
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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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 * - 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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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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/** @addtogroup fs
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 * @{
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 */
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#ifndef VFS_VFS_H_
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#define VFS_VFS_H_
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#include <ipc/ipc.h>
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#include <libadt/list.h>
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#include <atomic.h>
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#include <sys/types.h>
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#define dprintf(...)    printf(__VA_ARGS__)
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#define VFS_FIRST   FIRST_USER_METHOD
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#define IPC_METHOD_TO_VFS_OP(m) ((m) - VFS_FIRST)  
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typedef enum {
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    VFS_REGISTER = VFS_FIRST,
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    VFS_MOUNT,
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    VFS_UNMOUNT,
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    VFS_LOOKUP,
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    VFS_OPEN,
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    VFS_CREATE,
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    VFS_CLOSE,
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    VFS_READ,
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    VFS_WRITE,
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    VFS_SEEK,
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    VFS_LAST,       /* keep this the last member of the enum */
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} vfs_request_t;
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/**
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 * An instance of this structure is associated with a particular FS operation.
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 * It tells VFS if the FS supports the operation or maybe if a default one
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 * should be used.
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 */
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typedef enum {
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    VFS_OP_NULL = 0,
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    VFS_OP_DEFAULT,
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    VFS_OP_DEFINED
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} vfs_op_t;
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#define FS_NAME_MAXLEN  20
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/**
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 * A structure like this is passed to VFS by each individual FS upon its
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 * registration. It assosiates a human-readable identifier with each
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 * registered FS. More importantly, through this structure, the FS announces
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 * what operations it supports.
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 */
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typedef struct {
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    /** Unique identifier of the fs. */
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    char name[FS_NAME_MAXLEN];
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    /** Operations. */
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    vfs_op_t ops[VFS_LAST - VFS_FIRST];
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} vfs_info_t;
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/**
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 * A structure like this will be allocated for each registered file system.
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 */
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typedef struct {
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    link_t fs_link;
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    vfs_info_t vfs_info;
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    ipcarg_t phone;
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} fs_info_t;
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/**
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 * Instances of this type represent a file system node (e.g. directory, file).
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 * They are abstracted away from any file system implementation and contain just
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 * enough bits to uniquely identify the object in its file system instance.
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 *
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 * @note    fs_handle, dev_handle and index are meant to be returned in one
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 *      IPC reply.
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 */
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typedef struct {
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    int fs_handle;      /**< Global file system ID. */
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    int dev_handle;     /**< Global mount device devno. */
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    uint64_t index;     /**< Index of the node on its file system. */
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} vfs_node_t;
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/**
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 * Instances of this type represent an open file. If the file is opened by more
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 * than one task, there will be a separate structure allocated for each task.
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 */
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typedef struct {
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    vfs_node_t *node;
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    /** Number of file handles referencing this file. */
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    atomic_t refcnt;
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    /** Current position in the file. */
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    off_t pos;
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} vfs_file_t;
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extern link_t fs_head;      /**< List of registered file systems. */
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extern vfs_node_t *rootfs;  /**< Root node of the root file system. */
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#define MAX_PATH_LEN        (64 * 1024)
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#define PLB_SIZE        (2 * MAX_PATH_LEN)
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/** Each instance of this type describes one path lookup in progress. */
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typedef struct {
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    link_t  plb_link;   /**< Active PLB entries list link. */
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    unsigned index;     /**< Index of the first character in PLB. */
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    size_t len;     /**< Number of characters in this PLB entry. */
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} plb_entry_t;
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extern atomic_t plb_futex;  /**< Futex protecting plb and plb_head. */
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extern uint8_t *plb;        /**< Path Lookup Buffer */
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extern link_t plb_head;     /**< List of active PLB entries. */
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extern void vfs_register(ipc_callid_t, ipc_call_t *);
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extern void vfs_lookup(ipc_callid_t, ipc_call_t *);
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#endif
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/**
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 * @}
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 */