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/*

 * Copyright (c) 2008 Jakub Jermar

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/** @addtogroup fs

 * @{

 */

#ifndef VFS_VFS_H_

#define VFS_VFS_H_

#include <ipc/ipc.h>

#include <adt/list.h>

#include <futex.h>

#include <rwlock.h>

#include <sys/types.h>

#include <devmap.h>

#include <bool.h>

#include <ipc/vfs.h>

// FIXME: according to CONFIG_DEBUG

// #define dprintf(...)  printf(__VA_ARGS__)

#define dprintf(...)

/**

 * A structure like this will be allocated for each registered file system.

 */

typedef struct {

    link_t fs_link;

    vfs_info_t vfs_info;

    fs_handle_t fs_handle;

    futex_t phone_futex;    /**< Phone serializing futex. */

    ipcarg_t phone;

} fs_info_t;

/**

 * VFS_PAIR uniquely represents a file system instance.

 */

#define VFS_PAIR \

    fs_handle_t fs_handle; \

    dev_handle_t dev_handle;

/**

 * VFS_TRIPLET uniquely identifies a file system node (e.g. directory, file) but

 * doesn't contain any state. For a stateful structure, see vfs_node_t.

 *

 * @note    fs_handle, dev_handle and index are meant to be returned in one

 *      IPC reply.

 */

#define VFS_TRIPLET \

    VFS_PAIR; \

    fs_index_t index;

typedef struct {

    VFS_PAIR;

} vfs_pair_t;

typedef struct {

    VFS_TRIPLET;

} vfs_triplet_t;

typedef enum vfs_node_type {

    VFS_NODE_UNKNOWN,

    VFS_NODE_FILE,

    VFS_NODE_DIRECTORY,

} vfs_node_type_t;

typedef struct {

    vfs_triplet_t triplet;

    vfs_node_type_t type;

    size_t size;

    unsigned lnkcnt;

} vfs_lookup_res_t;

/**

 * Instances of this type represent an active, in-memory VFS node and any state

 * which may be associated with it.

 */

typedef struct {

    VFS_TRIPLET;        /**< Identity of the node. */

    /**

     * Usage counter.  This includes, but is not limited to, all vfs_file_t

     * structures that reference this node.

     */

    unsigned refcnt;

    /** Number of names this node has in the file system namespace. */

    unsigned lnkcnt;

    link_t nh_link;     /**< Node hash-table link. */

    vfs_node_type_t type;   /**< Partial info about the node type. */

    size_t size;        /**< Cached size if the node is a file. */

    /**

     * Holding this rwlock prevents modifications of the node's contents.

     */

    rwlock_t contents_rwlock;

} vfs_node_t;

/**

 * Instances of this type represent an open file. If the file is opened by more

 * than one task, there will be a separate structure allocated for each task.

 */

typedef struct {

    /** Serializes access to this open file. */

    futex_t lock;

    vfs_node_t *node;

    /** Number of file handles referencing this file. */

    unsigned refcnt;

    /** Append on write. */

    bool append;

    /** Current position in the file. */

    off_t pos;

} vfs_file_t;

extern futex_t nodes_futex;

extern link_t fs_head;      /**< List of registered file systems. */

extern vfs_pair_t rootfs;   /**< Root file system. */

/** Each instance of this type describes one path lookup in progress. */

typedef struct {

    link_t  plb_link;   /**< Active PLB entries list link. */

    unsigned index;     /**< Index of the first character in PLB. */

    size_t len;     /**< Number of characters in this PLB entry. */

} plb_entry_t;

extern futex_t plb_futex;   /**< Futex protecting plb and plb_head. */

extern uint8_t *plb;        /**< Path Lookup Buffer */

extern link_t plb_head;     /**< List of active PLB entries. */

#define MAX_MNTOPTS_LEN     256

/** Holding this rwlock prevents changes in file system namespace. */

extern rwlock_t namespace_rwlock;

extern int vfs_grab_phone(fs_handle_t);

extern void vfs_release_phone(int);

extern fs_handle_t fs_name_to_handle(char *, bool);

extern int vfs_lookup_internal(char *, int, vfs_lookup_res_t *,

    vfs_pair_t *, ...);

extern int vfs_open_node_internal(vfs_lookup_res_t *);

extern bool vfs_nodes_init(void);

extern vfs_node_t *vfs_node_get(vfs_lookup_res_t *);

extern void vfs_node_put(vfs_node_t *);

#define MAX_OPEN_FILES  128

extern bool vfs_files_init(void);

extern vfs_file_t *vfs_file_get(int);

extern int vfs_fd_alloc(void);

extern int vfs_fd_free(int);

extern void vfs_file_addref(vfs_file_t *);

extern void vfs_file_delref(vfs_file_t *);

extern void vfs_node_addref(vfs_node_t *);

extern void vfs_node_delref(vfs_node_t *);

extern void vfs_process_pending_mount(void);

extern void vfs_register(ipc_callid_t, ipc_call_t *);

extern void vfs_mount(ipc_callid_t, ipc_call_t *);

extern void vfs_open(ipc_callid_t, ipc_call_t *);

extern void vfs_open_node(ipc_callid_t, ipc_call_t *);

extern void vfs_device(ipc_callid_t, ipc_call_t *);

extern void vfs_sync(ipc_callid_t, ipc_call_t *);

extern void vfs_node(ipc_callid_t, ipc_call_t *);

extern void vfs_close(ipc_callid_t, ipc_call_t *);

extern void vfs_read(ipc_callid_t, ipc_call_t *);

extern void vfs_write(ipc_callid_t, ipc_call_t *);

extern void vfs_seek(ipc_callid_t, ipc_call_t *);

extern void vfs_truncate(ipc_callid_t, ipc_call_t *);

extern void vfs_mkdir(ipc_callid_t, ipc_call_t *);

extern void vfs_unlink(ipc_callid_t, ipc_call_t *);

extern void vfs_rename(ipc_callid_t, ipc_call_t *);

#endif

/**

 * @}

 */