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4419 trochtova 1
/*
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 * Copyright (c) 2008 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 <futex.h>
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#include <rwlock.h>
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#include <sys/types.h>
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#include <bool.h>
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// FIXME: according to CONFIG_DEBUG
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// #define dprintf(...) printf(__VA_ARGS__)
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#define dprintf(...)
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#define VFS_FIRST   IPC_FIRST_USER_METHOD
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/* Basic types. */
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typedef int16_t fs_handle_t;
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typedef int16_t dev_handle_t;
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typedef uint32_t fs_index_t;
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typedef enum {
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    VFS_READ = VFS_FIRST,
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    VFS_WRITE,
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    VFS_TRUNCATE,
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    VFS_MOUNT,
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    VFS_UNMOUNT,
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    VFS_LAST_CMN,   /* keep this the last member of this enum */
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} vfs_request_cmn_t;
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typedef enum {
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    VFS_LOOKUP = VFS_LAST_CMN,
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    VFS_MOUNTED,
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    VFS_DESTROY,
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    VFS_LAST_CLNT,  /* keep this the last member of this enum */
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} vfs_request_clnt_t;
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typedef enum {
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    VFS_REGISTER = VFS_LAST_CMN,
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    VFS_OPEN,
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    VFS_CLOSE,
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    VFS_SEEK,
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    VFS_MKDIR,
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    VFS_UNLINK,
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    VFS_RENAME,
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    VFS_LAST_SRV,   /* keep this the last member of this enum */
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} vfs_request_srv_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.
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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 + 1];
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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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    fs_handle_t fs_handle;
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    futex_t phone_futex;    /**< Phone serializing futex. */
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    ipcarg_t phone;
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} fs_info_t;
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/**
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 * VFS_PAIR uniquely represents a file system instance.
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 */
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#define VFS_PAIR        \
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    fs_handle_t fs_handle;  \
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    dev_handle_t dev_handle;
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/**
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 * VFS_TRIPLET uniquely identifies a file system node (e.g. directory, file) but
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 * doesn't contain any state. For a stateful structure, see vfs_node_t.
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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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#define VFS_TRIPLET \
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    VFS_PAIR;   \
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    fs_index_t index;
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typedef struct {
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    VFS_PAIR;
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} vfs_pair_t;
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typedef struct {
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    VFS_TRIPLET;
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} vfs_triplet_t;
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/*
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 * Lookup flags.
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 */
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/**
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 * No lookup flags used.
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 */
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#define L_NONE      0
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/**
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 * Lookup will succeed only if the object is a regular file.  If L_CREATE is
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 * specified, an empty file will be created. This flag is mutually exclusive
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 * with L_DIRECTORY.
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 */
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#define L_FILE      1
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/**
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 * Lookup wil succeed only if the object is a directory. If L_CREATE is
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 * specified, an empty directory will be created. This flag is mutually
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 * exclusive with L_FILE.
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 */
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#define L_DIRECTORY 2
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/**
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 * When used with L_CREATE, L_EXCLUSIVE will cause the lookup to fail if the
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 * object already exists. L_EXCLUSIVE is implied when L_DIRECTORY is used.
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 */
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#define L_EXCLUSIVE 4
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/**
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 * L_CREATE is used for creating both regular files and directories.
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 */
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#define L_CREATE    8
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/**
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 * L_LINK is used for linking to an already existing nodes.
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 */
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#define L_LINK      16
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/**
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 * L_UNLINK is used to remove leaves from the file system namespace. This flag
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 * cannot be passed directly by the client, but will be set by VFS during
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 * VFS_UNLINK.
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 */
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#define L_UNLINK    32  
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/**
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 * L_PARENT performs a lookup but returns the triplet of the parent node.
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 * This flag may not be combined with any other lookup flag.
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 */
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#define L_PARENT    64  
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typedef enum vfs_node_type {
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    VFS_NODE_UNKNOWN,
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    VFS_NODE_FILE,
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    VFS_NODE_DIRECTORY,
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} vfs_node_type_t;
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typedef struct {
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    vfs_triplet_t triplet;
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    vfs_node_type_t type;
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    size_t size;
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    unsigned lnkcnt;
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} vfs_lookup_res_t;
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/**
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 * Instances of this type represent an active, in-memory VFS node and any state
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 * which may be associated with it.
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 */
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typedef struct {
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    VFS_TRIPLET;        /**< Identity of the node. */
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    /**
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     * Usage counter.  This includes, but is not limited to, all vfs_file_t
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     * structures that reference this node.
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     */
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    unsigned refcnt;
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    /** Number of names this node has in the file system namespace. */
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    unsigned lnkcnt;
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    link_t nh_link;     /**< Node hash-table link. */
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    vfs_node_type_t type;   /**< Partial info about the node type. */
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    size_t size;        /**< Cached size if the node is a file. */
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    /**
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     * Holding this rwlock prevents modifications of the node's contents.
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     */
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    rwlock_t contents_rwlock;
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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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    /** Serializes access to this open file. */
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    futex_t lock;
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    vfs_node_t *node;
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    /** Number of file handles referencing this file. */
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    unsigned refcnt;
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    /** Append on write. */
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    bool append;
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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 futex_t nodes_futex;
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extern link_t fs_head;      /**< List of registered file systems. */
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extern vfs_pair_t rootfs;   /**< 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 futex_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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/** Holding this rwlock prevents changes in file system namespace. */
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extern rwlock_t namespace_rwlock;
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extern int vfs_grab_phone(fs_handle_t);
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extern void vfs_release_phone(int);
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extern fs_handle_t fs_name_to_handle(char *, bool);
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extern int vfs_lookup_internal(char *, int, vfs_lookup_res_t *, vfs_pair_t *,
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    ...);
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extern bool vfs_nodes_init(void);
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extern vfs_node_t *vfs_node_get(vfs_lookup_res_t *);
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extern void vfs_node_put(vfs_node_t *);
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#define MAX_OPEN_FILES  128
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extern bool vfs_files_init(void);
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extern vfs_file_t *vfs_file_get(int);
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extern int vfs_fd_alloc(void);
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extern int vfs_fd_free(int);
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extern void vfs_file_addref(vfs_file_t *);
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extern void vfs_file_delref(vfs_file_t *);
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extern void vfs_node_addref(vfs_node_t *);
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extern void vfs_node_delref(vfs_node_t *);
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extern void vfs_process_pending_mount(void);
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extern void vfs_register(ipc_callid_t, ipc_call_t *);
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extern void vfs_mount(ipc_callid_t, ipc_call_t *);
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extern void vfs_open(ipc_callid_t, ipc_call_t *);
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extern void vfs_close(ipc_callid_t, ipc_call_t *);
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extern void vfs_read(ipc_callid_t, ipc_call_t *);
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extern void vfs_write(ipc_callid_t, ipc_call_t *);
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extern void vfs_seek(ipc_callid_t, ipc_call_t *);
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extern void vfs_truncate(ipc_callid_t, ipc_call_t *);
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extern void vfs_mkdir(ipc_callid_t, ipc_call_t *);
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extern void vfs_unlink(ipc_callid_t, ipc_call_t *);
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extern void vfs_rename(ipc_callid_t, ipc_call_t *);
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#endif
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/**
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 * @}
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 */