source: mainline/uspace/srv/fs/fat/fat.h@ 7a35204a

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 7a35204a was b7b6753, checked in by Jakub Jermar <jakub@…>, 17 years ago

Put a frequently used construct into a function.
  • Property mode set to 100644
File size: 6.9 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#ifndef dprintf
44#define dprintf(...) printf(__VA_ARGS__)
45#endif
46
47typedef struct {
48 uint8_t ji[3]; /**< Jump instruction. */
49 uint8_t oem_name[8];
50 /* BIOS Parameter Block */
51 uint16_t bps; /**< Bytes per sector. */
52 uint8_t spc; /**< Sectors per cluster. */
53 uint16_t rscnt; /**< Reserved sector count. */
54 uint8_t fatcnt; /**< Number of FATs. */
55 uint16_t root_ent_max; /**< Maximum number of root directory
56 entries. */
57 uint16_t totsec16; /**< Total sectors. 16-bit version. */
58 uint8_t mdesc; /**< Media descriptor. */
59 uint16_t sec_per_fat; /**< Sectors per FAT12/FAT16. */
60 uint16_t sec_per_track; /**< Sectors per track. */
61 uint16_t headcnt; /**< Number of heads. */
62 uint32_t hidden_sec; /**< Hidden sectors. */
63 uint32_t totsec32; /**< Total sectors. 32-bit version. */
64
65 union {
66 struct {
67 /* FAT12/FAT16 only: Extended BIOS Parameter Block */
68 /** Physical drive number. */
69 uint8_t pdn;
70 uint8_t reserved;
71 /** Extended boot signature. */
72 uint8_t ebs;
73 /** Serial number. */
74 uint32_t id;
75 /** Volume label. */
76 uint8_t label[11];
77 /** FAT type. */
78 uint8_t type[8];
79 /** Boot code. */
80 uint8_t boot_code[448];
81 /** Boot sector signature. */
82 uint16_t signature;
83 } __attribute__ ((packed));
84 struct {
85 /* FAT32 only */
86 /** Sectors per FAT. */
87 uint32_t sectors_per_fat;
88 /** FAT flags. */
89 uint16_t flags;
90 /** Version. */
91 uint16_t version;
92 /** Cluster number of root directory. */
93 uint32_t root_cluster;
94 /** Sector number of file system information sector. */
95 uint16_t fsinfo_sec;
96 /** Sector number of boot sector copy. */
97 uint16_t bscopy_sec;
98 uint8_t reserved1[12];
99 /** Physical drive number. */
100 uint8_t pdn;
101 uint8_t reserved2;
102 /** Extended boot signature. */
103 uint8_t ebs;
104 /** Serial number. */
105 uint32_t id;
106 /** Volume label. */
107 uint8_t label[11];
108 /** FAT type. */
109 uint8_t type[8];
110 /** Boot code. */
111 uint8_t boot_code[420];
112 /** Signature. */
113 uint16_t signature;
114 } __attribute__ ((packed));
115 };
116} __attribute__ ((packed)) fat_bs_t;
117
118#define FAT_ATTR_RDONLY (1 << 0)
119#define FAT_ATTR_VOLLABEL (1 << 3)
120#define FAT_ATTR_SUBDIR (1 << 4)
121
122typedef struct {
123 uint8_t name[8];
124 uint8_t ext[3];
125 uint8_t attr;
126 uint8_t reserved;
127 uint8_t ctime_fine;
128 uint16_t ctime;
129 uint16_t cdate;
130 uint16_t adate;
131 union {
132 uint16_t eaidx; /* FAT12/FAT16 */
133 uint16_t firstc_hi; /* FAT32 */
134 };
135 uint16_t mtime;
136 uint16_t mdate;
137 union {
138 uint16_t firstc; /* FAT12/FAT16 */
139 uint16_t firstc_lo; /* FAT32 */
140 };
141 uint32_t size;
142} __attribute__ ((packed)) fat_dentry_t;
143
144typedef uint16_t fat_cluster_t;
145
146typedef enum {
147 FAT_INVALID,
148 FAT_DIRECTORY,
149 FAT_FILE
150} fat_node_type_t;
151
152struct fat_node;
153
154/** FAT index structure.
155 *
156 * This structure exists to help us to overcome certain limitations of the FAT
157 * file system design. The problem with FAT is that it is hard to find
158 * an entity which could represent a VFS index. There are two candidates:
159 *
160 * a) number of the node's first cluster
161 * b) the pair of the parent directory's first cluster and the dentry index
162 * within the parent directory
163 *
164 * We need VFS indices to be:
165 * A) unique
166 * B) stable in time, at least until the next mount
167 *
168 * Unfortunately a) does not meet the A) criterion because zero-length files
169 * will have the first cluster field cleared. And b) does not meet the B)
170 * criterion because unlink() and rename() will both free up the original
171 * dentry, which contains all the essential info about the file.
172 *
173 * Therefore, a completely opaque indices are used and the FAT server maintains
174 * a mapping between them and otherwise nice b) variant. On rename(), the VFS
175 * index stays unaltered, while the internal FAT "physical tree address"
176 * changes. The unlink case is also handled this way thanks to an in-core node
177 * pointer embedded in the index structure.
178 */
179typedef struct {
180 /** Used indices (position) hash table link. */
181 link_t uph_link;
182 /** Used indices (index) hash table link. */
183 link_t uih_link;
184
185 futex_t lock;
186 dev_handle_t dev_handle;
187 fs_index_t index;
188 /**
189 * Parent node's first cluster.
190 * Zero is used if this node is not linked, in which case nodep must
191 * contain a pointer to the in-core node structure.
192 * One is used when the parent is the root directory.
193 */
194 fat_cluster_t pfc;
195 /** Directory entry index within the parent node. */
196 unsigned pdi;
197 /** Pointer to in-core node instance. */
198 struct fat_node *nodep;
199} fat_idx_t;
200
201/** FAT in-core node. */
202typedef struct fat_node {
203 futex_t lock;
204 fat_node_type_t type;
205 fat_idx_t *idx;
206 /**
207 * Node's first cluster.
208 * Zero is used for zero-length nodes.
209 * One is used to mark root directory.
210 */
211 fat_cluster_t firstc;
212 /** FAT in-core node free list link. */
213 link_t ffn_link;
214 size_t size;
215 unsigned lnkcnt;
216 unsigned refcnt;
217 bool dirty;
218} fat_node_t;
219
220extern fs_reg_t fat_reg;
221
222extern void fat_mounted(ipc_callid_t, ipc_call_t *);
223extern void fat_mount(ipc_callid_t, ipc_call_t *);
224extern void fat_lookup(ipc_callid_t, ipc_call_t *);
225
226extern fat_idx_t *fat_idx_get_by_pos(dev_handle_t, fat_cluster_t, unsigned);
227extern fat_idx_t *fat_idx_get_by_index(dev_handle_t, fs_index_t);
228
229extern int fat_idx_init(void);
230extern void fat_idx_fini(void);
231extern int fat_idx_init_by_dev_handle(dev_handle_t);
232extern void fat_idx_fini_by_dev_handle(dev_handle_t);
233
234#endif
235
236/**
237 * @}
238 */
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