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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 <fibril_sync.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;
    fibril_mutex_t phone_lock;
    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.
     */
    fibril_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. */
    fibril_mutex_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 fibril_mutex_t nodes_mutex;

extern fibril_condvar_t fs_head_cv;
extern fibril_mutex_t fs_head_lock;
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 fibril_mutex_t plb_mutex;/**< Mutex 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 fibril_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_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_sync(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_fstat(ipc_callid_t, ipc_call_t *);
extern void vfs_fstat(ipc_callid_t, ipc_call_t *);
extern void vfs_stat(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

/**
 * @}
 */