src/system/boot/loader/file_systems/bfs/bfs.cpp

   1 /*
   2  * Copyright 2003-2013, Axel Dörfler, axeld@pinc-software.de.
   3  * Distributed under the terms of the MIT License.
   4  */
   5
   6
   7 #include <fcntl.h>
   8 #include <unistd.h>
   9 #include <string.h>
  10 #include <stdio.h>
  11
  12 #include <boot/partitions.h>
  13 #include <boot/platform.h>
  14 #include <boot/vfs.h>
  15
  16 #include "Volume.h"
  17 #include "Directory.h"
  18 #include "Utility.h"
  19
  20
  21 #define TRACE_BFS 0
  22 #if TRACE_BFS
  23 #       define TRACE(x) dprintf x
  24 #else
  25 #       define TRACE(x) ;
  26 #endif
  27
  28
  29 using namespace BFS;
  30 using std::nothrow;
  31
  32
  33 Volume::Volume(boot::Partition *partition)
  34         :
  35         fRootNode(NULL)
  36 {
  37         fDevice = open_node(partition, O_RDONLY);
  38         if (fDevice < B_OK)
  39                 return;
  40
  41         if (read_pos(fDevice, 512, &fSuperBlock, sizeof(disk_super_block)) < B_OK)
  42                 return;
  43
  44         if (!IsValidSuperBlock()) {
  45 #ifndef BFS_LITTLE_ENDIAN_ONLY
  46                 // try block 0 again (can only happen on the big endian BFS)
  47                 if (read_pos(fDevice, 0, &fSuperBlock, sizeof(disk_super_block)) < B_OK)
  48                         return;
  49
  50                 if (!IsValidSuperBlock())
  51                         return;
  52 #else
  53                 return;
  54 #endif
  55         }
  56
  57         TRACE(("bfs: we do have a valid superblock (name = %s)!\n", fSuperBlock.name));
  58
  59         fRootNode = new(nothrow) BFS::Directory(*this, Root());
  60         if (fRootNode == NULL)
  61                 return;
  62
  63         if (fRootNode->InitCheck() < B_OK) {
  64                 TRACE(("bfs: init check for root node failed\n"));
  65                 delete fRootNode;
  66                 fRootNode = NULL;
  67                 return;
  68         }
  69 }
  70
  71
  72 Volume::~Volume()
  73 {
  74         close(fDevice);
  75 }
  76
  77
  78 status_t
  79 Volume::InitCheck()
  80 {
  81         if (fDevice < B_OK)
  82                 return B_ERROR;
  83
  84         return fRootNode != NULL ? B_OK : B_ERROR;
  85 }
  86
  87
  88 bool
  89 Volume::IsValidSuperBlock()
  90 {
  91         if (fSuperBlock.Magic1() != (int32)SUPER_BLOCK_MAGIC1
  92                 || fSuperBlock.Magic2() != (int32)SUPER_BLOCK_MAGIC2
  93                 || fSuperBlock.Magic3() != (int32)SUPER_BLOCK_MAGIC3
  94                 || (int32)fSuperBlock.block_size != fSuperBlock.inode_size
  95                 || fSuperBlock.ByteOrder() != SUPER_BLOCK_FS_LENDIAN
  96                 || (1UL << fSuperBlock.BlockShift()) != fSuperBlock.BlockSize()
  97                 || fSuperBlock.AllocationGroups() < 1
  98                 || fSuperBlock.AllocationGroupShift() < 1
  99                 || fSuperBlock.BlocksPerAllocationGroup() < 1
 100                 || fSuperBlock.NumBlocks() < 10
 101                 || fSuperBlock.AllocationGroups() != divide_roundup(fSuperBlock.NumBlocks(), 1L << fSuperBlock.AllocationGroupShift()))
 102                 return false;
 103
 104         return true;
 105 }
 106
 107
 108 status_t
 109 Volume::ValidateBlockRun(block_run run)
 110 {
 111         if (run.AllocationGroup() < 0 || run.AllocationGroup() > (int32)AllocationGroups()
 112                 || run.Start() > (1UL << AllocationGroupShift())
 113                 || run.length == 0
 114                 || uint32(run.Length() + run.Start()) > (1UL << AllocationGroupShift())) {
 115                 dprintf("bfs: invalid run(%" B_PRId32 ",%d,%d)\n",
 116                         run.AllocationGroup(), run.Start(), run.Length());
 117                 return B_BAD_DATA;
 118         }
 119         return B_OK;
 120 }
 121
 122
 123 block_run
 124 Volume::ToBlockRun(off_t block) const
 125 {
 126         block_run run;
 127         run.allocation_group = HOST_ENDIAN_TO_BFS_INT32(block >> fSuperBlock.AllocationGroupShift());
 128         run.start = HOST_ENDIAN_TO_BFS_INT16(block & ~((1LL << fSuperBlock.AllocationGroupShift()) - 1));
 129         run.length = HOST_ENDIAN_TO_BFS_INT16(1);
 130         return run;
 131 }
 132
 133
 134 //      #pragma mark -
 135
 136
 137 float
 138 bfs_identify_file_system(boot::Partition *partition)
 139 {
 140         Volume volume(partition);
 141
 142         return volume.InitCheck() < B_OK ? 0 : 0.8;
 143 }
 144
 145
 146 static status_t
 147 bfs_get_file_system(boot::Partition *partition, ::Directory **_root)
 148 {
 149         Volume *volume = new(nothrow) Volume(partition);
 150         if (volume == NULL)
 151                 return B_NO_MEMORY;
 152
 153         if (volume->InitCheck() < B_OK) {
 154                 delete volume;
 155                 return B_ERROR;
 156         }
 157
 158         *_root = volume->RootNode();
 159         return B_OK;
 160 }
 161
 162
 163 file_system_module_info gBFSFileSystemModule = {
 164         "file_systems/bfs/v1",
 165         kPartitionTypeBFS,
 166         bfs_identify_file_system,
 167         bfs_get_file_system
 168 };
 169