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1/*
2 * Copyright (C) 2007-2023 Xagasoft, All rights reserved.
3 *
4 * This file is part of the libbu++ library and is released under the
5 * terms of the license contained in the file LICENSE.
6 */
7
8#ifndef MYRIAD_FS_H
9#define MYRIAD_FS_H
10
11#include <sys/types.h>
12
13#include "bu/myriad.h"
14#include "bu/readwritemutex.h"
15
16namespace Bu
17{
18 class Stream;
19
20 subExceptionDecl( MyriadFsException );
21
22 /**
23 * A POSIX compliant, node based filesystem built on top of Myriad.
24 *
25 * A header is placed into stream 1.
26 * Header format:
27 * int32_t iMagicHeader (A7188B39)
28 * int8_t iVersion (1)
29 * int32_t iNumNodes
30 * NodeLookup[iNumNodes] nNode
31 *
32 * Node lookup:
33 * int32_t iInode
34 * int32_t iPosition
35 *
36 * The node headers or inode structures have a base size of 44 bytes.
37 * The name is stored in the directory format.
38 * Basic node header format:
39 * int32_t iNode
40 * int32_t iUser
41 * int32_t iGroup
42 * uint16_t uPerms
43 * int16_t iLinks
44 * uint32_t uStreamIndex
45 * int64_t iATime
46 * int64_t iMTime
47 * int64_t iCTime
48 *
49 * Some types get special formats for their assosiated data stream, or
50 * other special considerations, here's a list:
51 *
52 * - typeFifo: No stream, uStreamIndex unused (probably)
53 * - typeChrDev: No stream, uStreamIndex is device hi/lo
54 * - typeDir: The stream contains a directory contents listing, described
55 * below
56 * - typeBlkDev: No stream, uStreamIndex is device hi/lo
57 * - typeRegFile: The stream is the file data
58 * - typeSymLink: The stream is the destination of the symlink
59 * - typeSocket: No steram, uStreamIndex unused (probably)
60 *
61 * Directory streams have this simple listing format. They contain a list
62 * of all child elements, with no particular order at the moment. The . and
63 * .. entries are not listed, they are implicit:
64 * int32_t iNumNodes
65 * NodeTable[iNumNodes] nChildren
66 *
67 * NodeTable:
68 * int32_t iInode
69 * uint8_t uNameSize
70 * char[uNameSize] sName
71 */
72 class MyriadFs
73 {
74 public:
75 MyriadFs( Bu::Stream &rStore, int iBlockSize=512 );
76 virtual ~MyriadFs();
77
78 enum
79 {
80 permOthX = 0000001,
81 permOthW = 0000002,
82 permOthR = 0000004,
83 permGrpX = 0000010,
84 permGrpW = 0000020,
85 permGrpR = 0000040,
86 permUsrX = 0000100,
87 permUsrW = 0000200,
88 permUsrR = 0000400,
89 permSticky = 0001000,
90 permSetGid = 0002000,
91 permSetUid = 0004000,
92 permMask = 0007777,
93 typeFifo = 0010000,
94 typeChrDev = 0020000,
95 typeDir = 0040000,
96 typeBlkDev = 0060000,
97 typeRegFile = 0100000,
98 typeSymLink = 0120000,
99 typeSocket = 0140000,
100 typeMask = 0170000
101 };
102
103 enum
104 {
105 Read = 0x01, ///< Open file for reading
106 Write = 0x02, ///< Open file for writing
107 Create = 0x04, ///< Create file if it doesn't exist
108 Truncate = 0x08, ///< Truncate file if it does exist
109 Append = 0x10, ///< Always append on every write
110 NonBlock = 0x20, ///< Open file in non-blocking mode
111 Exclusive = 0x44, ///< Create file, if it exists then fail
112
113 // Helpful mixes
114 ReadWrite = 0x03, ///< Open for reading and writing
115 WriteNew = 0x0E ///< Create a file (or truncate) for writing.
116 /// Same as Write|Create|Truncate
117 };
118
119 class Stat
120 {
121 public:
122 int32_t iNode;
123 int32_t iUser;
124 int32_t iGroup;
125 uint16_t uPerms;
126 int16_t iLinks;
127 int64_t iATime;
128 int64_t iMTime;
129 int64_t iCTime;
130 int32_t iSize;
131 uint32_t uDev;
132 Bu::String sName;
133 };
134 typedef Bu::List<Stat> Dir;
135
136 void stat( const Bu::String &sPath, Stat &rBuf );
137 MyriadStream open( const Bu::String &sPath, int iMode,
138 uint16_t uPerms=0664 );
139 void create( const Bu::String &sPath, uint16_t iPerms );
140 void create( const Bu::String &sPath, uint16_t iPerms,
141 uint16_t iDevHi, uint16_t iDevLo );
142 void create( const Bu::String &sPath, uint16_t iPerms,
143 uint32_t uSpecial );
144 void mkDir( const Bu::String &sPath, uint16_t iPerms );
145 void mkSymLink( const Bu::String &sTarget, const Bu::String &sPath );
146 void mkHardLink( const Bu::String &sTarget, const Bu::String &sPath );
147 Bu::String readSymLink( const Bu::String &sPath );
148 Dir readDir( const Bu::String &sPath );
149 void setTimes( const Bu::String &sPath, int64_t iATime,
150 int64_t iMTime );
151 void unlink( const Bu::String &sPath );
152 void setFileSize( const Bu::String &sPath, int32_t iSize );
153 void rename( const Bu::String &sFrom, const Bu::String &sTo );
154
155 static dev_t devToSys( uint32_t uDev );
156 static uint32_t sysToDev( dev_t uDev );
157
158 private:
159 class RawStat
160 {
161 public:
162 int32_t iNode;
163 int32_t iUser;
164 int32_t iGroup;
165 uint16_t uPerms;
166 int16_t iLinks;
167 uint32_t uStreamIndex;
168 int64_t iATime;
169 int64_t iMTime;
170 int64_t iCTime;
171 };
172 typedef Bu::Hash<int32_t, int32_t> NodeIndex;
173
174 private:
175 int32_t lookupInode( const Bu::String &sPath, int32_t &iParent );
176 int32_t lookupInode( Bu::String::const_iterator iStart,
177 int32_t iNode, int32_t &iParent );
178 void readInode( int32_t iNode, RawStat &rs, MyriadStream &rIs );
179 void readInode( int32_t iNode, RawStat &rs );
180 void writeInode( const RawStat &rs );
181 void writeInode( const RawStat &rs, MyriadStream &rOs );
182 Dir readDir( int32_t iNode );
183 MyriadStream openByInode( int32_t iNode );
184 void addToDir( int32_t iDir, int32_t iNode, const Bu::String &sName );
185 int32_t create( int32_t iParent, const Bu::String &sName,
186 uint16_t uPerms, uint32_t uSpecial );
187 int32_t allocInode( uint16_t uPerms, uint32_t uSpecial );
188 void stat( int32_t iNode, Stat &rBuf, MyriadStream &rIs );
189 void writeHeader();
190 void setTimes( int32_t iNode, int64_t iATime, int64_t iMTime );
191 void destroyNode( int32_t iNode );
192
193 Bu::String filePart( const Bu::String &sPath );
194
195 private:
196 Bu::Stream &rStore;
197 Bu::Myriad mStore;
198 Bu::ReadWriteMutex mNodeIndex;
199 NodeIndex hNodeIndex;
200 int32_t iUser;
201 int32_t iGroup;
202 };
203};
204
205#endif
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