1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
/*
* Copyright (C) 2007-2011 Xagasoft, All rights reserved.
*
* This file is part of the libbu++ library and is released under the
* terms of the license contained in the file LICENSE.
*/
#ifndef MYRIAD_FS_H
#define MYRIAD_FS_H
#include "bu/myriad.h"
namespace Bu
{
class Stream;
subExceptionDecl( MyriadFsException );
/**
* A POSIX compliant, node based filesystem built on top of Myriad.
*
* A header is placed into stream 1.
* Header format:
* int32_t iMagicHeader (A7188B39)
* int8_t iVersion (1)
* int32_t iNumNodes
* NodeLookup[iNumNodes] nNode
*
* Node lookup:
* int32_t iInode
* int32_t iPosition
*
* The node headers or inode structures have a base size of 46 bytes.
* Everything else in the block is used for the name. I.e. if you have
* a blocksize of 512 bytes then you wind up with a max name size of
* 512-46=466 characters, or a blocksize of 256 gives you 210 chraacters
* as a max. The node headers are all stored in stream 2.
* Basic node header format:
* int32_t iUser
* int32_t iGroup
* int16_t iPerms
* int16_t iLinks
* int32_t iStreamIndex
* int32_t iParentNode
* int64_t iATime
* int64_t iMTime
* int64_t iCTime
* int16_t iNameSize
* char[iNameSize] sName
*
* Some types get special formats for their assosiated data stream, or
* other special considerations, here's a list:
*
* - typeFifo: No stream, iStreamIndex unused (probably)
* - typeChrDev: No stream, iStreamIndex is device hi/lo
* - typeDir: The stream contains a directory contents listing, described
* below
* - typeBlkDev: No stream, iStreamIndex is device hi/lo
* - typeRegFile: The stream is the file data
* - typeSymLink: The stream is the destination of the symlink
* - typeSocket: No steram, iStreamIndex unused (probably)
*
* Directory streams have this simple listing format. They contain a list
* of all child elements, with no particular order at the moment. The . and
* .. entries are not listed, they are implicit:
* int32_t iNumNodes
* NodeTable[iNumNodes] nChildren
*
* NodeTable:
* int32_t iInode
*/
class MyriadFs
{
public:
MyriadFs( Bu::Stream &rStore, int iBlockSize=512 );
virtual ~MyriadFs();
enum
{
permOthX = 0000001,
permOthW = 0000002,
permOthR = 0000004,
permGrpX = 0000010,
permGrpW = 0000020,
permGrpR = 0000040,
permUsrX = 0000100,
permUsrW = 0000200,
permUsrR = 0000400,
permSticky = 0001000,
permSetGid = 0002000,
permSetUid = 0004000,
typeFifo = 0010000,
typeChrDev = 0020000,
typeDir = 0040000,
typeBlkDev = 0060000,
typeRegFile = 0100000,
typeSymLink = 0120000,
typeSocket = 0140000,
typeMask = 0170000
};
enum
{
Read = 0x01, ///< Open file for reading
Write = 0x02, ///< Open file for writing
Create = 0x04, ///< Create file if it doesn't exist
Truncate = 0x08, ///< Truncate file if it does exist
Append = 0x10, ///< Always append on every write
NonBlock = 0x20, ///< Open file in non-blocking mode
Exclusive = 0x44, ///< Create file, if it exists then fail
// Helpful mixes
ReadWrite = 0x03, ///< Open for reading and writing
WriteNew = 0x0E ///< Create a file (or truncate) for writing.
/// Same as Write|Create|Truncate
};
class Stat
{
public:
int32_t iNode;
int32_t iUser;
int32_t iGroup;
uint16_t uPerms;
int16_t iLinks;
int64_t iATime;
int64_t iMTime;
int64_t iCTime;
int32_t iSize;
Bu::String sName;
};
typedef Bu::List<Stat> Dir;
void stat( const Bu::String &sPath, Stat &rBuf );
MyriadStream open( const Bu::String &sPath, int iMode );
// void create( const Bu::String &sPath, uint16_t iPerms );
private:
class RawStat
{
public:
int32_t iUser;
int32_t iGroup;
uint16_t uPerms;
int16_t iLinks;
int32_t iStreamIndex;
int32_t iParentNode;
int64_t iATime;
int64_t iMTime;
int64_t iCTime;
int16_t iNameSize;
};
typedef Bu::Hash<int32_t, int32_t> NodeIndex;
private:
int32_t lookupInode( const Bu::String &sPath, int32_t &iParent );
int32_t lookupInode( Bu::String::const_iterator iStart,
int32_t iNode, int32_t &iParent );
Dir readDir( int32_t iNode );
MyriadStream openByInode( int32_t iNode );
int32_t create( int32_t iParent, const Bu::String &sName,
uint16_t uPerms );
int32_t allocInode( const Bu::String &sName, int32_t iParent,
uint16_t uPerms );
void stat( int32_t iNode, Stat &rBuf, MyriadStream &rIs );
void writeHeader();
private:
Bu::Stream &rStore;
Bu::Myriad mStore;
NodeIndex hNodeIndex;
int32_t iUser;
int32_t iGroup;
};
};
#endif
|
