1 // SuperBlock.cpp 2 // 3 // Copyright (c) 2003, Ingo Weinhold (bonefish@cs.tu-berlin.de) 4 // 5 // This program is free software; you can redistribute it and/or modify 6 // it under the terms of the GNU General Public License as published by 7 // the Free Software Foundation; either version 2 of the License, or 8 // (at your option) any later version. 9 // 10 // This program is distributed in the hope that it will be useful, 11 // but WITHOUT ANY WARRANTY; without even the implied warranty of 12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 // GNU General Public License for more details. 14 // 15 // You should have received a copy of the GNU General Public License 16 // along with this program; if not, write to the Free Software 17 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 18 // 19 // You can alternatively use *this file* under the terms of the the MIT 20 // license included in this package. 21 22 #include <new> 23 #include <string.h> 24 #include <unistd.h> 25 26 #include "Debug.h" 27 #include "SuperBlock.h" 28 29 using std::nothrow; 30 31 /*! 32 \class DirEntry 33 \brief Represents the on-disk structure for super block of the FS. 34 35 There exist two versions of the structure and this class can deal with 36 both of them. The Init() methods tries to find and read the super block 37 from disk. 38 */ 39 40 // read_super_block 41 template<typename super_block_t> 42 static 43 status_t 44 read_super_block(int device, off_t offset, const char *magic, 45 super_block_t **_superBlock) 46 { 47 super_block_t *superBlock = NULL; 48 status_t error = B_OK; 49 // allocate memory for the super block 50 if (error == B_OK) { 51 superBlock = new(nothrow) super_block_t; 52 if (!superBlock) 53 error = B_NO_MEMORY; 54 } 55 // read the super block 56 if (error == B_OK) { 57 size_t size = sizeof(super_block_t); 58 if (read_pos(device, offset, superBlock, size) != (int32)size) 59 error = B_IO_ERROR; 60 } 61 // check magic 62 if (error == B_OK) { 63 size_t len = strlen(magic); 64 if (strncmp(superBlock->s_magic, magic, len)) 65 error = B_ERROR; 66 } 67 // set result / cleanup on failure 68 if (error == B_OK) 69 *_superBlock = superBlock; 70 else if (superBlock) 71 delete superBlock; 72 return error; 73 } 74 75 // constructor 76 SuperBlock::SuperBlock() 77 : fFormatVersion(REISERFS_3_6), 78 fCurrentData(NULL) 79 { 80 } 81 82 // destructor 83 SuperBlock::~SuperBlock() 84 { 85 if (GetFormatVersion() == REISERFS_3_6) { 86 if (fCurrentData) 87 delete fCurrentData; 88 } else { 89 if (fOldData) 90 delete fOldData; 91 } 92 } 93 94 // Init 95 status_t 96 SuperBlock::Init(int device, off_t offset) 97 { 98 // Not sure, if I understand the weird versioning. 99 status_t error = B_OK; 100 // try old version 101 if (read_super_block(device, REISERFS_OLD_DISK_OFFSET_IN_BYTES + offset, 102 REISERFS_SUPER_MAGIC_STRING, &fOldData) == B_OK) { 103 PRINT(("SuperBlock: ReiserFS 3.5\n")); 104 fFormatVersion = REISERFS_3_5; 105 // try new version 106 } else if (read_super_block(device, REISERFS_DISK_OFFSET_IN_BYTES + offset, 107 REISER2FS_SUPER_MAGIC_STRING, &fOldData) == B_OK) { 108 PRINT(("SuperBlock: ReiserFS 3.6\n")); 109 fFormatVersion = REISERFS_3_6; 110 // failure 111 } else 112 error = B_ERROR; 113 // TODO: checks... 114 return error; 115 } 116 117