Subversion Repositories HelenOS

Rev

Rev 4419 | Rev 4537 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
4419 trochtova 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
 
53
typedef struct fat_bs {
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
typedef enum {
125
    FAT_INVALID,
126
    FAT_DIRECTORY,
127
    FAT_FILE
128
} fat_node_type_t;
129
 
130
struct fat_node;
131
 
132
/** FAT index structure.
133
 *
134
 * This structure exists to help us to overcome certain limitations of the FAT
135
 * file system design.  The problem with FAT is that it is hard to find
136
 * an entity which could represent a VFS index.  There are two candidates:
137
 *
138
 * a) number of the node's first cluster
139
 * b) the pair of the parent directory's first cluster and the dentry index
140
 *    within the parent directory
141
 *
142
 * We need VFS indices to be:
143
 * A) unique
144
 * B) stable in time, at least until the next mount
145
 *
146
 * Unfortunately a) does not meet the A) criterion because zero-length files
147
 * will have the first cluster field cleared.  And b) does not meet the B)
148
 * criterion because unlink() and rename() will both free up the original
149
 * dentry, which contains all the essential info about the file.
150
 *
151
 * Therefore, a completely opaque indices are used and the FAT server maintains
152
 * a mapping between them and otherwise nice b) variant.  On rename(), the VFS
153
 * index stays unaltered, while the internal FAT "physical tree address"
154
 * changes.  The unlink case is also handled this way thanks to an in-core node
155
 * pointer embedded in the index structure.
156
 */
157
typedef struct {
158
    /** Used indices (position) hash table link. */
159
    link_t      uph_link;
160
    /** Used indices (index) hash table link. */
161
    link_t      uih_link;
162
 
163
    futex_t     lock;
164
    dev_handle_t    dev_handle;
165
    fs_index_t  index;
166
    /**
167
     * Parent node's first cluster.
168
     * Zero is used if this node is not linked, in which case nodep must
169
     * contain a pointer to the in-core node structure.
170
     * One is used when the parent is the root directory.
171
     */
172
    fat_cluster_t   pfc;
173
    /** Directory entry index within the parent node. */
174
    unsigned    pdi;
175
    /** Pointer to in-core node instance. */
176
    struct fat_node *nodep;
177
} fat_idx_t;
178
 
179
/** FAT in-core node. */
180
typedef struct fat_node {
4420 trochtova 181
    /** Back pointer to the FS node. */
182
    fs_node_t       *bp;
183
 
4419 trochtova 184
    futex_t         lock;
185
    fat_node_type_t     type;
186
    fat_idx_t       *idx;
187
    /**
188
     *  Node's first cluster.
189
     *  Zero is used for zero-length nodes.
190
     *  One is used to mark root directory.
191
     */
192
    fat_cluster_t       firstc;
193
    /** FAT in-core node free list link. */
194
    link_t          ffn_link;
195
    size_t          size;
196
    unsigned        lnkcnt;
197
    unsigned        refcnt;
198
    bool            dirty;
199
} fat_node_t;
200
 
201
extern fs_reg_t fat_reg;
202
 
203
extern void fat_mounted(ipc_callid_t, ipc_call_t *);
204
extern void fat_mount(ipc_callid_t, ipc_call_t *);
205
extern void fat_lookup(ipc_callid_t, ipc_call_t *);
206
extern void fat_read(ipc_callid_t, ipc_call_t *);
207
extern void fat_write(ipc_callid_t, ipc_call_t *);
208
extern void fat_truncate(ipc_callid_t, ipc_call_t *);
209
extern void fat_destroy(ipc_callid_t, ipc_call_t *);
210
 
211
extern fat_idx_t *fat_idx_get_new(dev_handle_t);
212
extern fat_idx_t *fat_idx_get_by_pos(dev_handle_t, fat_cluster_t, unsigned);
213
extern fat_idx_t *fat_idx_get_by_index(dev_handle_t, fs_index_t);
214
extern void fat_idx_destroy(fat_idx_t *);
215
extern void fat_idx_hashin(fat_idx_t *);
216
extern void fat_idx_hashout(fat_idx_t *);
217
 
218
extern int fat_idx_init(void);
219
extern void fat_idx_fini(void);
220
extern int fat_idx_init_by_dev_handle(dev_handle_t);
221
extern void fat_idx_fini_by_dev_handle(dev_handle_t);
222
 
223
#endif
224
 
225
/**
226
 * @}
227
 */