Subversion Repositories HelenOS

/*

 * 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 FAT_FAT_H_

#define FAT_FAT_H_

#include "fat_fat.h"

#include <ipc/ipc.h>

#include <libfs.h>

#include <atomic.h>

#include <sys/types.h>

#include <bool.h>

#include "../../vfs/vfs.h"

#ifndef dprintf

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

#endif

#define min(a, b)       ((a) < (b) ? (a) : (b))

#define BS_BLOCK        0

#define BS_SIZE         512

typedef struct fat_bs {

    uint8_t     ji[3];      /**< Jump instruction. */

    uint8_t     oem_name[8];

    /* BIOS Parameter Block */

    uint16_t    bps;        /**< Bytes per sector. */

    uint8_t     spc;        /**< Sectors per cluster. */

    uint16_t    rscnt;      /**< Reserved sector count. */

    uint8_t     fatcnt;     /**< Number of FATs. */

    uint16_t    root_ent_max;   /**< Maximum number of root directory

                         entries. */

    uint16_t    totsec16;   /**< Total sectors. 16-bit version. */

    uint8_t     mdesc;      /**< Media descriptor. */

    uint16_t    sec_per_fat;    /**< Sectors per FAT12/FAT16. */

    uint16_t    sec_per_track;  /**< Sectors per track. */

    uint16_t    headcnt;    /**< Number of heads. */

    uint32_t    hidden_sec; /**< Hidden sectors. */

    uint32_t    totsec32;   /**< Total sectors. 32-bit version. */

    union {

        struct {

            /* FAT12/FAT16 only: Extended BIOS Parameter Block */

            /** Physical drive number. */

            uint8_t     pdn;

            uint8_t     reserved;

            /** Extended boot signature. */

            uint8_t     ebs;

            /** Serial number. */

            uint32_t    id;

            /** Volume label. */

            uint8_t     label[11];

            /** FAT type. */

            uint8_t     type[8];

            /** Boot code. */

            uint8_t     boot_code[448];

            /** Boot sector signature. */

            uint16_t    signature;

        } __attribute__ ((packed));

        struct {

            /* FAT32 only */

            /** Sectors per FAT. */

            uint32_t    sectors_per_fat;

            /** FAT flags. */

            uint16_t    flags;

            /** Version. */

            uint16_t    version;

            /** Cluster number of root directory. */

            uint32_t    root_cluster;

            /** Sector number of file system information sector. */

            uint16_t    fsinfo_sec;

            /** Sector number of boot sector copy. */

            uint16_t    bscopy_sec;

            uint8_t     reserved1[12];

            /** Physical drive number. */

            uint8_t     pdn;

            uint8_t     reserved2;

            /** Extended boot signature. */

            uint8_t     ebs;

            /** Serial number. */

            uint32_t    id;

            /** Volume label. */

            uint8_t     label[11];

            /** FAT type. */

            uint8_t     type[8];

            /** Boot code. */

            uint8_t     boot_code[420];

            /** Signature. */

            uint16_t    signature;

        } __attribute__ ((packed));

    };

} __attribute__ ((packed)) fat_bs_t;

typedef enum {

    FAT_INVALID,

    FAT_DIRECTORY,

    FAT_FILE

} fat_node_type_t;

struct fat_node;

/** FAT index structure.

 *

 * This structure exists to help us to overcome certain limitations of the FAT

 * file system design.  The problem with FAT is that it is hard to find

 * an entity which could represent a VFS index.  There are two candidates:

 *

 * a) number of the node's first cluster

 * b) the pair of the parent directory's first cluster and the dentry index

 *    within the parent directory

 *

 * We need VFS indices to be:

 * A) unique

 * B) stable in time, at least until the next mount

 *

 * Unfortunately a) does not meet the A) criterion because zero-length files

 * will have the first cluster field cleared.  And b) does not meet the B)

 * criterion because unlink() and rename() will both free up the original

 * dentry, which contains all the essential info about the file.

 *

 * Therefore, a completely opaque indices are used and the FAT server maintains

 * a mapping between them and otherwise nice b) variant.  On rename(), the VFS

 * index stays unaltered, while the internal FAT "physical tree address"

 * changes.  The unlink case is also handled this way thanks to an in-core node

 * pointer embedded in the index structure.

 */

typedef struct {

    /** Used indices (position) hash table link. */

    link_t      uph_link;

    /** Used indices (index) hash table link. */

    link_t      uih_link;

    futex_t     lock;

    dev_handle_t    dev_handle;

    fs_index_t  index;

    /**

     * Parent node's first cluster.

     * Zero is used if this node is not linked, in which case nodep must

     * contain a pointer to the in-core node structure.

     * One is used when the parent is the root directory.

     */

    fat_cluster_t   pfc;

    /** Directory entry index within the parent node. */

    unsigned    pdi;

    /** Pointer to in-core node instance. */

    struct fat_node *nodep;

} fat_idx_t;

/** FAT in-core node. */

typedef struct fat_node {

    futex_t         lock;

    fat_node_type_t     type;

    fat_idx_t       *idx;

    /**

     *  Node's first cluster.

     *  Zero is used for zero-length nodes.

     *  One is used to mark root directory.

     */

    fat_cluster_t       firstc;

    /** FAT in-core node free list link. */

    link_t          ffn_link;

    size_t          size;

    unsigned        lnkcnt;

    unsigned        refcnt;

    bool            dirty;

} fat_node_t;

extern fs_reg_t fat_reg;

extern void fat_mounted(ipc_callid_t, ipc_call_t *);

extern void fat_mount(ipc_callid_t, ipc_call_t *);

extern void fat_lookup(ipc_callid_t, ipc_call_t *);

extern void fat_read(ipc_callid_t, ipc_call_t *);

extern void fat_write(ipc_callid_t, ipc_call_t *);

extern void fat_truncate(ipc_callid_t, ipc_call_t *);

extern void fat_destroy(ipc_callid_t, ipc_call_t *);

extern fat_idx_t *fat_idx_get_new(dev_handle_t);

extern fat_idx_t *fat_idx_get_by_pos(dev_handle_t, fat_cluster_t, unsigned);

extern fat_idx_t *fat_idx_get_by_index(dev_handle_t, fs_index_t);

extern void fat_idx_destroy(fat_idx_t *);

extern void fat_idx_hashin(fat_idx_t *);

extern int fat_idx_init(void);

extern void fat_idx_fini(void);

extern int fat_idx_init_by_dev_handle(dev_handle_t);

extern void fat_idx_fini_by_dev_handle(dev_handle_t);

#endif

/**

 * @}

 */