WebSVN – HelenOS – Blame – /trunk/uspace/srv/fs/fat/fat.h/

Rev	Author	Line No.	Line
2627	jermar	1	/*
2789	jermar	2	* Copyright (c) 2008 Jakub Jermar
2627	jermar	3	* All rights reserved.
		4	*
		5	* Redistribution and use in source and binary forms, with or without
		6	* modification, are permitted provided that the following conditions
		7	* are met:
		8	*
		9	* - Redistributions of source code must retain the above copyright
		10	* notice, this list of conditions and the following disclaimer.
		11	* - Redistributions in binary form must reproduce the above copyright
		12	* notice, this list of conditions and the following disclaimer in the
		13	* documentation and/or other materials provided with the distribution.
		14	* - The name of the author may not be used to endorse or promote products
		15	* derived from this software without specific prior written permission.
		16	*
		17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
		18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
		19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
		20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
		21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
		22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
		23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
		24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
		25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
		26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
		27	*/
		28
		29	/** @addtogroup fs
		30	* @{
		31	*/
		32
		33	#ifndef FAT_FAT_H_
		34	#define FAT_FAT_H_
		35
		36	#include <ipc/ipc.h>
2643	jermar	37	#include <libfs.h>
2627	jermar	38	#include <atomic.h>
		39	#include <sys/types.h>
		40	#include <bool.h>
2789	jermar	41	#include "../../vfs/vfs.h"
2627	jermar	42
		43	#define dprintf(...) printf(__VA_ARGS__)
		44
2628	jermar	45	typedef struct {
		46	uint8_t ji[3]; /*< Jump instruction. /
		47	uint8_t oem_name[8];
		48	/* BIOS Parameter Block */
		49	uint16_t bps; /*< Bytes per sector. /
		50	uint8_t spc; /*< Sectors per cluster. /
2789	jermar	51	uint16_t rscnt; /*< Reserved sector count. /
2628	jermar	52	uint8_t fatcnt; /*< Number of FATs. /
		53	uint16_t root_ent_max; /**< Maximum number of root directory
		54	entries. */
2789	jermar	55	uint16_t totsec16; /*< Total sectors. 16-bit version. /
2628	jermar	56	uint8_t mdesc; /*< Media descriptor. /
		57	uint16_t sec_per_fat; /*< Sectors per FAT12/FAT16. /
		58	uint16_t sec_per_track; /*< Sectors per track. /
		59	uint16_t headcnt; /*< Number of heads. /
		60	uint32_t hidden_sec; /*< Hidden sectors. /
2831	jermar	61	uint32_t totsec32; /*< Total sectors. 32-bit version. /
2628	jermar	62
		63	union {
		64	struct {
		65	/* FAT12/FAT16 only: Extended BIOS Parameter Block */
		66	/** Physical drive number. */
		67	uint8_t pdn;
		68	uint8_t reserved;
		69	/** Extended boot signature. */
		70	uint8_t ebs;
		71	/** Serial number. */
		72	uint32_t id;
		73	/** Volume label. */
		74	uint8_t label[11];
		75	/** FAT type. */
		76	uint8_t type[8];
		77	/** Boot code. */
		78	uint8_t boot_code[448];
		79	/** Boot sector signature. */
		80	uint16_t signature;
		81	} __attribute__ ((packed));
		82	struct {
		83	/* FAT32 only */
		84	/** Sectors per FAT. */
		85	uint32_t sectors_per_fat;
		86	/** FAT flags. */
		87	uint16_t flags;
		88	/** Version. */
		89	uint16_t version;
		90	/** Cluster number of root directory. */
		91	uint32_t root_cluster;
		92	/** Sector number of file system information sector. */
		93	uint16_t fsinfo_sec;
		94	/** Sector number of boot sector copy. */
		95	uint16_t bscopy_sec;
		96	uint8_t reserved1[12];
		97	/** Physical drive number. */
		98	uint8_t pdn;
		99	uint8_t reserved2;
		100	/** Extended boot signature. */
		101	uint8_t ebs;
		102	/** Serial number. */
		103	uint32_t id;
		104	/** Volume label. */
2789	jermar	105	uint8_t label[11];
2628	jermar	106	/** FAT type. */
		107	uint8_t type[8];
		108	/** Boot code. */
		109	uint8_t boot_code[420];
		110	/** Signature. */
		111	uint16_t signature;
		112	} __attribute__ ((packed));
		113	};
2629	jermar	114	} __attribute__ ((packed)) fat_bs_t;
2628	jermar	115
2793	jermar	116	#define FAT_ATTR_RDONLY (1 << 0)
		117	#define FAT_ATTR_VOLLABEL (1 << 3)
		118	#define FAT_ATTR_SUBDIR (1 << 4)
		119
2629	jermar	120	typedef struct {
		121	uint8_t name[8];
		122	uint8_t ext[3];
		123	uint8_t attr;
		124	uint8_t reserved;
		125	uint8_t ctime_fine;
		126	uint16_t ctime;
		127	uint16_t cdate;
		128	uint16_t adate;
		129	union {
		130	uint16_t eaidx; /* FAT12/FAT16 */
		131	uint16_t firstc_hi; /* FAT32 */
		132	};
		133	uint16_t mtime;
		134	uint16_t mdate;
		135	union {
		136	uint16_t firstc; /* FAT12/FAT16 */
		137	uint16_t firstc_lo; /* FAT32 */
		138	};
		139	uint32_t size;
		140	} __attribute__ ((packed)) fat_dentry_t;
		141
2864	jermar	142	typedef uint16_t fat_cluster_t;
		143
2789	jermar	144	typedef enum {
2831	jermar	145	FAT_INVALID,
2789	jermar	146	FAT_DIRECTORY,
		147	FAT_FILE
		148	} fat_node_type_t;
		149
2864	jermar	150	struct fat_node;
		151
		152	/** FAT index structure.
		153	*
		154	* This structure exists to help us to overcome certain limitations of the FAT
		155	* file system design. The problem with FAT is that it is hard to find
		156	* an entity which could represent a VFS index. There are two candidates:
		157	*
		158	* a) number of the node's first cluster
		159	* b) the pair of the parent directory's first cluster and the dentry index
		160	* within the parent directory
		161	*
		162	* We need VFS indices to be:
		163	* A) unique
		164	* B) stable in time, at least until the next mount
		165	*
		166	* Unfortunately a) does not meet the A) criterion because zero-length files
		167	* will have the first cluster field cleared. And b) does not meet the B)
		168	* criterion because unlink() and rename() will both free up the original
		169	* dentry, which contains all the essential info about the file.
		170	*
		171	* Therefore, a completely opaque indices are used and the FAT server maintains
		172	* a mapping between them and otherwise nice b) variant. On rename(), the VFS
		173	* index stays unaltered, while the internal FAT "physical tree address"
		174	* changes. The unlink case is also handled this way thanks to an in-core node
		175	* pointer embedded in the index structure.
		176	*/
		177	typedef struct {
2889	jermar	178	/** Used indices hash table link. */
		179	link_t uh_link;
		180
2864	jermar	181	dev_handle_t dev_handle;
		182	fs_index_t index;
		183	/**
2889	jermar	184	* Parent node's first cluster.
2864	jermar	185	* Zero is used if this node is not linked, in which case nodep must
		186	* contain a pointer to the in-core node structure.
		187	* One is used when the parent is the root directory.
		188	*/
		189	fat_cluster_t pfc;
2889	jermar	190	/** Directory entry index within the parent node. */
2864	jermar	191	unsigned pdi;
		192	/** Pointer to in-core node instance. */
		193	struct fat_node *nodep;
		194	} fat_idx_t;
		195
2789	jermar	196	/** FAT in-core node. */
2864	jermar	197	typedef struct fat_node {
2789	jermar	198	fat_node_type_t type;
2864	jermar	199	fat_idx_t *idx;
		200	/**
		201	* Node's first cluster.
		202	* Zero is used for zero-length nodes.
		203	* One is used to mark root directory.
		204	*/
		205	fat_cluster_t firstc;
2789	jermar	206	/** FAT in-core node hash table link. */
		207	link_t fin_link;
2831	jermar	208	/** FAT in-core node free list link. */
		209	link_t ffn_link;
2789	jermar	210	size_t size;
		211	unsigned lnkcnt;
2831	jermar	212	unsigned refcnt;
		213	bool dirty;
2789	jermar	214	} fat_node_t;
		215
2643	jermar	216	extern fs_reg_t fat_reg;
2627	jermar	217
2638	jermar	218	extern void fat_lookup(ipc_callid_t, ipc_call_t *);
		219
2881	jermar	220	extern fat_idx_t *fat_idx_map(dev_handle_t, fat_cluster_t, unsigned);
2876	jermar	221
2627	jermar	222	#endif
		223
		224	/**
		225	* @}
		226	*/

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