source: mainline/uspace/srv/fs/fat/fat.h@ 0f57d0e

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 0f57d0e was 0f57d0e, checked in by Jakub Jermar <jakub@…>, 17 years ago

Move functionality related to manipulatings file allocation tables to fat_fat.c.
  • Property mode set to 100644
File size: 6.8 KB
Line 
1/*
2 * Copyright (c) 2008 Jakub 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 "fat_fat.h"
37#include <ipc/ipc.h>
38#include <libfs.h>
39#include <atomic.h>
40#include <sys/types.h>
41#include <bool.h>
42#include "../../vfs/vfs.h"
43
44#ifndef dprintf
45#define dprintf(...) printf(__VA_ARGS__)
46#endif
47
48#define min(a, b) ((a) < (b) ? (a) : (b))
49
50#define BS_BLOCK 0
51#define BS_SIZE 512
52
53typedef struct {
54 uint8_t ji[3]; /**< Jump instruction. */
55 uint8_t oem_name[8];
56 /* BIOS Parameter Block */
57 uint16_t bps; /**< Bytes per sector. */
58 uint8_t spc; /**< Sectors per cluster. */
59 uint16_t rscnt; /**< Reserved sector count. */
60 uint8_t fatcnt; /**< Number of FATs. */
61 uint16_t root_ent_max; /**< Maximum number of root directory
62 entries. */
63 uint16_t totsec16; /**< Total sectors. 16-bit version. */
64 uint8_t mdesc; /**< Media descriptor. */
65 uint16_t sec_per_fat; /**< Sectors per FAT12/FAT16. */
66 uint16_t sec_per_track; /**< Sectors per track. */
67 uint16_t headcnt; /**< Number of heads. */
68 uint32_t hidden_sec; /**< Hidden sectors. */
69 uint32_t totsec32; /**< Total sectors. 32-bit version. */
70
71 union {
72 struct {
73 /* FAT12/FAT16 only: Extended BIOS Parameter Block */
74 /** Physical drive number. */
75 uint8_t pdn;
76 uint8_t reserved;
77 /** Extended boot signature. */
78 uint8_t ebs;
79 /** Serial number. */
80 uint32_t id;
81 /** Volume label. */
82 uint8_t label[11];
83 /** FAT type. */
84 uint8_t type[8];
85 /** Boot code. */
86 uint8_t boot_code[448];
87 /** Boot sector signature. */
88 uint16_t signature;
89 } __attribute__ ((packed));
90 struct {
91 /* FAT32 only */
92 /** Sectors per FAT. */
93 uint32_t sectors_per_fat;
94 /** FAT flags. */
95 uint16_t flags;
96 /** Version. */
97 uint16_t version;
98 /** Cluster number of root directory. */
99 uint32_t root_cluster;
100 /** Sector number of file system information sector. */
101 uint16_t fsinfo_sec;
102 /** Sector number of boot sector copy. */
103 uint16_t bscopy_sec;
104 uint8_t reserved1[12];
105 /** Physical drive number. */
106 uint8_t pdn;
107 uint8_t reserved2;
108 /** Extended boot signature. */
109 uint8_t ebs;
110 /** Serial number. */
111 uint32_t id;
112 /** Volume label. */
113 uint8_t label[11];
114 /** FAT type. */
115 uint8_t type[8];
116 /** Boot code. */
117 uint8_t boot_code[420];
118 /** Signature. */
119 uint16_t signature;
120 } __attribute__ ((packed));
121 };
122} __attribute__ ((packed)) fat_bs_t;
123
124#define FAT_BS(b) ((fat_bs_t *)((b)->data))
125
126typedef enum {
127 FAT_INVALID,
128 FAT_DIRECTORY,
129 FAT_FILE
130} fat_node_type_t;
131
132struct fat_node;
133
134/** FAT index structure.
135 *
136 * This structure exists to help us to overcome certain limitations of the FAT
137 * file system design. The problem with FAT is that it is hard to find
138 * an entity which could represent a VFS index. There are two candidates:
139 *
140 * a) number of the node's first cluster
141 * b) the pair of the parent directory's first cluster and the dentry index
142 * within the parent directory
143 *
144 * We need VFS indices to be:
145 * A) unique
146 * B) stable in time, at least until the next mount
147 *
148 * Unfortunately a) does not meet the A) criterion because zero-length files
149 * will have the first cluster field cleared. And b) does not meet the B)
150 * criterion because unlink() and rename() will both free up the original
151 * dentry, which contains all the essential info about the file.
152 *
153 * Therefore, a completely opaque indices are used and the FAT server maintains
154 * a mapping between them and otherwise nice b) variant. On rename(), the VFS
155 * index stays unaltered, while the internal FAT "physical tree address"
156 * changes. The unlink case is also handled this way thanks to an in-core node
157 * pointer embedded in the index structure.
158 */
159typedef struct {
160 /** Used indices (position) hash table link. */
161 link_t uph_link;
162 /** Used indices (index) hash table link. */
163 link_t uih_link;
164
165 futex_t lock;
166 dev_handle_t dev_handle;
167 fs_index_t index;
168 /**
169 * Parent node's first cluster.
170 * Zero is used if this node is not linked, in which case nodep must
171 * contain a pointer to the in-core node structure.
172 * One is used when the parent is the root directory.
173 */
174 fat_cluster_t pfc;
175 /** Directory entry index within the parent node. */
176 unsigned pdi;
177 /** Pointer to in-core node instance. */
178 struct fat_node *nodep;
179} fat_idx_t;
180
181/** FAT in-core node. */
182typedef struct fat_node {
183 futex_t lock;
184 fat_node_type_t type;
185 fat_idx_t *idx;
186 /**
187 * Node's first cluster.
188 * Zero is used for zero-length nodes.
189 * One is used to mark root directory.
190 */
191 fat_cluster_t firstc;
192 /** FAT in-core node free list link. */
193 link_t ffn_link;
194 size_t size;
195 unsigned lnkcnt;
196 unsigned refcnt;
197 bool dirty;
198} fat_node_t;
199
200/* TODO move somewhere else */
201typedef struct block {
202 void *data;
203 size_t size;
204 bool dirty;
205} block_t;
206
207extern block_t *block_get(dev_handle_t, off_t, size_t);
208extern void block_put(block_t *);
209
210extern fs_reg_t fat_reg;
211
212extern void fat_mounted(ipc_callid_t, ipc_call_t *);
213extern void fat_mount(ipc_callid_t, ipc_call_t *);
214extern void fat_lookup(ipc_callid_t, ipc_call_t *);
215extern void fat_read(ipc_callid_t, ipc_call_t *);
216extern void fat_write(ipc_callid_t, ipc_call_t *);
217
218extern fat_idx_t *fat_idx_get_by_pos(dev_handle_t, fat_cluster_t, unsigned);
219extern fat_idx_t *fat_idx_get_by_index(dev_handle_t, fs_index_t);
220
221extern int fat_idx_init(void);
222extern void fat_idx_fini(void);
223extern int fat_idx_init_by_dev_handle(dev_handle_t);
224extern void fat_idx_fini_by_dev_handle(dev_handle_t);
225
226#endif
227
228/**
229 * @}
230 */
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