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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 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 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 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
/**
* @}
*/