source: mainline/uspace/srv/fs/fat/fat.h@ 78a1b7b

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 78a1b7b was 2c4bbcde, checked in by Jakub Jermar <jakub@…>, 17 years ago

More bits of fat_node_get().
Still needs to do some locking.
  • Property mode set to 100644
File size: 6.6 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 <ipc/ipc.h>
37#include <libfs.h>
38#include <atomic.h>
39#include <sys/types.h>
40#include <bool.h>
41#include "../../vfs/vfs.h"
42
43#define dprintf(...) printf(__VA_ARGS__)
44
45typedef 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. */
51 uint16_t rscnt; /**< Reserved sector count. */
52 uint8_t fatcnt; /**< Number of FATs. */
53 uint16_t root_ent_max; /**< Maximum number of root directory
54 entries. */
55 uint16_t totsec16; /**< Total sectors. 16-bit version. */
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. */
61 uint32_t totsec32; /**< Total sectors. 32-bit version. */
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. */
105 uint8_t label[11];
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 };
114} __attribute__ ((packed)) fat_bs_t;
115
116#define FAT_ATTR_RDONLY (1 << 0)
117#define FAT_ATTR_VOLLABEL (1 << 3)
118#define FAT_ATTR_SUBDIR (1 << 4)
119
120typedef 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
142typedef uint16_t fat_cluster_t;
143
144typedef enum {
145 FAT_INVALID,
146 FAT_DIRECTORY,
147 FAT_FILE
148} fat_node_type_t;
149
150struct 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 */
177typedef struct {
178 /** Used indices (position) hash table link. */
179 link_t uph_link;
180 /** Used indices (index) hash table link. */
181 link_t uih_link;
182
183 dev_handle_t dev_handle;
184 fs_index_t index;
185 /**
186 * Parent node's first cluster.
187 * Zero is used if this node is not linked, in which case nodep must
188 * contain a pointer to the in-core node structure.
189 * One is used when the parent is the root directory.
190 */
191 fat_cluster_t pfc;
192 /** Directory entry index within the parent node. */
193 unsigned pdi;
194 /** Pointer to in-core node instance. */
195 struct fat_node *nodep;
196} fat_idx_t;
197
198/** FAT in-core node. */
199typedef struct fat_node {
200 fat_node_type_t type;
201 fat_idx_t *idx;
202 /**
203 * Node's first cluster.
204 * Zero is used for zero-length nodes.
205 * One is used to mark root directory.
206 */
207 fat_cluster_t firstc;
208 /** FAT in-core node free list link. */
209 link_t ffn_link;
210 size_t size;
211 unsigned lnkcnt;
212 unsigned refcnt;
213 bool dirty;
214} fat_node_t;
215
216extern fs_reg_t fat_reg;
217
218extern void fat_lookup(ipc_callid_t, ipc_call_t *);
219
220extern fat_idx_t *fat_idx_get_by_pos(dev_handle_t, fat_cluster_t, unsigned);
221extern fat_idx_t *fat_idx_get_by_index(dev_handle_t, fs_index_t);
222
223#endif
224
225/**
226 * @}
227 */
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