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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

/**

 * @}

 */