/*
* Copyright (c) 2008 Jakub Jermar
* Copyright (c) 2011 Oleg Romanenko
* 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 fat
* @{
*/
#ifndef FAT_FAT_H_
#define FAT_FAT_H_
#include "fat_fat.h"
#include <fibril_synch.h>
#include <libfs.h>
#include <stdint.h>
#include <stdbool.h>
#include <macros.h>
#include "../../vfs/vfs.h"
#ifndef dprintf
#define dprintf(...) printf(__VA_ARGS__)
#endif
/*
* Convenience macros for accessing some frequently used boot sector members.
*/
#define BPS(bs) uint16_t_le2host((bs)->bps)
#define SPC(bs) (bs)->spc
#define RSCNT(bs) uint16_t_le2host((bs)->rscnt)
#define FATCNT(bs) (bs)->fatcnt
#define SF(bs) (uint16_t_le2host((bs)->sec_per_fat) ? \
uint16_t_le2host((bs)->sec_per_fat) : \
uint32_t_le2host(bs->fat32.sectors_per_fat))
#define RDE(bs) uint16_t_le2host((bs)->root_ent_max)
#define TS(bs) (uint16_t_le2host((bs)->totsec16) ? \
uint16_t_le2host((bs)->totsec16) : \
uint32_t_le2host(bs->totsec32))
#define BS_BLOCK 0
#define BS_SIZE 512
typedef struct fat_bs {
/** Jump instruction */
uint8_t ji[3];
uint8_t oem_name[8];
/* BIOS Parameter Block */
/** Bytes per sector */
uint16_t bps;
/** Sectors per cluster */
uint8_t spc;
/** Reserved sector count */
uint16_t rscnt;
/** Number of FATs */
uint8_t fatcnt;
/** Maximum number of root directory entries */
uint16_t root_ent_max;
/** Total sectors. 16-bit version */
uint16_t totsec16;
/** Media descriptor */
uint8_t mdesc;
/** Sectors per FAT12/FAT16 */
uint16_t sec_per_fat;
/** Sectors per track */
uint16_t sec_per_track;
/** Number of heads */
uint16_t headcnt;
/** Hidden sectors */
uint32_t hidden_sec;
/** Total sectors. 32-bit version */
uint32_t totsec32;
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)) fat32;
};
} __attribute__((packed)) fat_bs_t;
#define FAT32_FSINFO_SIG1 "RRaA"
#define FAT32_FSINFO_SIG2 "rrAa"
#define FAT32_FSINFO_SIG3 "\x00\x00\x55\xaa"
typedef struct {
uint8_t sig1[4];
uint8_t res1[480];
uint8_t sig2[4];
uint32_t free_clusters;
uint32_t last_allocated_cluster;
uint8_t res2[12];
uint8_t sig3[4];
} __attribute__((packed)) fat32_fsinfo_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. */
ht_link_t uph_link;
/** Used indices (index) hash table link. */
ht_link_t uih_link;
fibril_mutex_t lock;
service_id_t service_id;
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 {
/** Back pointer to the FS node. */
fs_node_t *bp;
fibril_mutex_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;
aoff64_t size;
unsigned lnkcnt;
unsigned refcnt;
bool dirty;
/*
* Cache of the node's last and "current" cluster to avoid some
* unnecessary FAT walks.
*/
/* Node's last cluster in FAT. */
bool lastc_cached_valid;
fat_cluster_t lastc_cached_value;
/* Node's "current" cluster, i.e. where the last I/O took place. */
bool currc_cached_valid;
aoff64_t currc_cached_bn;
fat_cluster_t currc_cached_value;
} fat_node_t;
typedef struct {
bool lfn_enabled;
} fat_instance_t;
extern vfs_out_ops_t fat_ops;
extern libfs_ops_t fat_libfs_ops;
extern errno_t fat_idx_get_new(fat_idx_t **, service_id_t);
extern fat_idx_t *fat_idx_get_by_pos(service_id_t, fat_cluster_t, unsigned);
extern fat_idx_t *fat_idx_get_by_index(service_id_t, fs_index_t);
extern void fat_idx_destroy(fat_idx_t *);
extern void fat_idx_hashin(fat_idx_t *);
extern void fat_idx_hashout(fat_idx_t *);
extern errno_t fat_idx_init(void);
extern void fat_idx_fini(void);
extern errno_t fat_idx_init_by_service_id(service_id_t);
extern void fat_idx_fini_by_service_id(service_id_t);
#endif
/**
* @}
*/