1 /* bsd.cc -- Functions for loading and manipulating legacy BSD disklabel
4 /* By Rod Smith, initial coding August, 2009 */
6 /* This program is copyright (c) 2009 by Roderick W. Smith. It is distributed
7 under the terms of the GNU GPL version 2, as detailed in the COPYING file. */
9 #define __STDC_LIMIT_MACROS
10 #define __STDC_CONSTANT_MACROS
27 BSDData::BSDData(void) {
29 signature = UINT32_C(0);
30 signature2 = UINT32_C(0);
35 labelStart = LABEL_OFFSET1; // assume raw disk format
37 } // default constructor
39 BSDData::~BSDData(void) {
43 // Read BSD disklabel data from the specified device filename. This function
44 // just opens the device file and then calls an overloaded function to do
45 // the bulk of the work. Returns 1 on success, 0 on failure.
46 int BSDData::ReadBSDData(const string & device, uint64_t startSector, uint64_t endSector) {
51 if (myDisk.OpenForRead(device)) {
52 allOK = ReadBSDData(&myDisk, startSector, endSector);
62 } // BSDData::ReadBSDData() (device filename version)
64 // Load the BSD disklabel data from an already-opened disk
65 // file, starting with the specified sector number.
66 int BSDData::ReadBSDData(DiskIO *theDisk, uint64_t startSector, uint64_t endSector) {
68 int i, foundSig = 0, bigEnd = 0;
69 int relative = 0; // assume absolute partition sector numbering
70 uint8_t buffer[4096]; // I/O buffer
74 BSDRecord* tempRecords;
75 int offset[NUM_OFFSETS] = { LABEL_OFFSET1, LABEL_OFFSET2 };
77 labelFirstLBA = startSector;
78 labelLastLBA = endSector;
79 offset[1] = theDisk->GetBlockSize();
81 // Read 4096 bytes (eight 512-byte sectors or equivalent)
82 // into memory; we'll extract data from this buffer.
83 // (Done to work around FreeBSD limitation on size of reads
84 // from block devices.)
85 allOK = theDisk->Seek(startSector);
86 if (allOK) allOK = theDisk->Read(buffer, 4096);
88 // Do some strangeness to support big-endian architectures...
89 bigEnd = (IsLittleEndian() == 0);
90 realSig = BSD_SIGNATURE;
92 ReverseBytes(&realSig, 4);
94 // Look for the signature at any of two locations.
95 // Note that the signature is repeated at both the original
96 // offset and 132 bytes later, so we need two checks....
100 temp32 = (uint32_t*) &buffer[offset[i]];
102 if (signature == realSig) { // found first, look for second
103 temp32 = (uint32_t*) &buffer[offset[i] + 132];
104 signature2 = *temp32;
105 if (signature2 == realSig) {
107 labelStart = offset[i];
108 } // if found signature
111 } while ((!foundSig) && (i < NUM_OFFSETS));
115 // Load partition metadata from the buffer....
117 temp32 = (uint32_t*) &buffer[labelStart + 40];
118 sectorSize = *temp32;
119 temp16 = (uint16_t*) &buffer[labelStart + 138];
123 // Make it big-endian-aware....
124 if ((IsLittleEndian() == 0) && allOK)
127 // Check validity of the data and flag it appropriately....
128 if (foundSig && (numParts <= MAX_BSD_PARTS) && allOK) {
134 // If the state is good, go ahead and load the main partition data....
136 partitions = new struct BSDRecord[numParts * sizeof(struct BSDRecord)];
137 if (partitions == NULL) {
138 cerr << "Unable to allocate memory in BSDData::ReadBSDData()! Terminating!\n";
141 for (i = 0; i < numParts; i++) {
142 // Once again, we use the buffer, but index it using a BSDRecord
143 // pointer (dangerous, but effective)....
144 tempRecords = (BSDRecord*) &buffer[labelStart + 148];
145 partitions[i].lengthLBA = tempRecords[i].lengthLBA;
146 partitions[i].firstLBA = tempRecords[i].firstLBA;
147 partitions[i].fsType = tempRecords[i].fsType;
148 if (bigEnd) { // reverse data (fsType is a single byte)
149 ReverseBytes(&partitions[i].lengthLBA, 4);
150 ReverseBytes(&partitions[i].firstLBA, 4);
152 // Check for signs of relative sector numbering: A "0" first sector
153 // number on a partition with a non-zero length -- but ONLY if the
154 // length is less than the disk size, since NetBSD has a habit of
155 // creating a disk-sized partition within a carrier MBR partition
156 // that's too small to house it, and this throws off everything....
157 if ((partitions[i].firstLBA == 0) && (partitions[i].lengthLBA > 0)
158 && (partitions[i].lengthLBA < labelLastLBA))
161 // Some disklabels use sector numbers relative to the enclosing partition's
162 // start, others use absolute sector numbers. If relative numbering was
163 // detected above, apply a correction to all partition start sectors....
165 for (i = 0; i < numParts; i++) {
166 partitions[i].firstLBA += (uint32_t) startSector;
169 } // if signatures OK
172 } // BSDData::ReadBSDData(DiskIO* theDisk, uint64_t startSector)
174 // Reverse metadata's byte order; called only on big-endian systems
175 void BSDData::ReverseMetaBytes(void) {
176 ReverseBytes(&signature, 4);
177 ReverseBytes(§orSize, 4);
178 ReverseBytes(&signature2, 4);
179 ReverseBytes(&numParts, 2);
180 } // BSDData::ReverseMetaByteOrder()
182 // Display basic BSD partition data. Used for debugging.
183 void BSDData::DisplayBSDData(void) {
187 cout << "BSD partitions:\n";
188 for (i = 0; i < numParts; i++) {
190 cout << i + 1 << "\t";
192 cout << partitions[i].firstLBA << "\t";
194 cout << partitions[i].lengthLBA << " \t0x";
197 cout.setf(ios::uppercase);
198 cout << hex << (int) partitions[i].fsType << "\n" << dec;
202 } // BSDData::DisplayBSDData()
204 // Displays the BSD disklabel state. Called during program launch to inform
205 // the user about the partition table(s) status
206 int BSDData::ShowState(void) {
211 cout << " BSD: not present\n";
214 cout << " BSD: present\n";
218 cout << "\a BSD: unknown -- bug!\n";
222 } // BSDData::ShowState()
224 // Weirdly, this function has stopped working when defined inline,
225 // but it's OK here....
226 int BSDData::IsDisklabel(void) {
227 return (state == bsd);
228 } // BSDData::IsDiskLabel()
230 // Returns the BSD table's partition type code
231 uint8_t BSDData::GetType(int i) {
232 uint8_t retval = 0; // 0 = "unused"
234 if ((i < numParts) && (i >= 0) && (state == bsd) && (partitions != 0))
235 retval = partitions[i].fsType;
238 } // BSDData::GetType()
240 // Returns the number of the first sector of the specified partition
241 uint64_t BSDData::GetFirstSector(int i) {
242 uint64_t retval = UINT64_C(0);
244 if ((i < numParts) && (i >= 0) && (state == bsd) && (partitions != 0))
245 retval = (uint64_t) partitions[i].firstLBA;
248 } // BSDData::GetFirstSector
250 // Returns the length (in sectors) of the specified partition
251 uint64_t BSDData::GetLength(int i) {
252 uint64_t retval = UINT64_C(0);
254 if ((i < numParts) && (i >= 0) && (state == bsd) && (partitions != 0))
255 retval = (uint64_t) partitions[i].lengthLBA;
258 } // BSDData::GetLength()
260 // Returns the number of partitions defined in the current table
261 int BSDData::GetNumParts(void) {
263 } // BSDData::GetNumParts()
265 // Returns the specified partition as a GPT partition. Used in BSD-to-GPT
266 // conversion process
267 GPTPart BSDData::AsGPT(int i) {
268 GPTPart guid; // dump data in here, then return it
269 uint64_t sectorOne, sectorEnd; // first & last sectors of partition
270 int passItOn = 1; // Set to 0 if partition is empty or invalid
272 guid.BlankPartition();
273 sectorOne = (uint64_t) partitions[i].firstLBA;
274 sectorEnd = sectorOne + (uint64_t) partitions[i].lengthLBA;
275 if (sectorEnd > 0) sectorEnd--;
276 // Note on above: BSD partitions sometimes have a length of 0 and a start
277 // sector of 0. With unsigned ints, the usual way (start + length - 1) to
278 // find the end will result in a huge number, which will be confusing.
279 // Thus, apply the "-1" part only if it's reasonable to do so.
281 // Do a few sanity checks on the partition before we pass it on....
282 // First, check that it falls within the bounds of its container
283 // and that it starts before it ends....
284 if ((sectorOne < labelFirstLBA) || (sectorEnd > labelLastLBA) || (sectorOne > sectorEnd))
286 // Some disklabels include a pseudo-partition that's the size of the entire
287 // disk or containing partition. Don't return it.
288 if ((sectorOne <= labelFirstLBA) && (sectorEnd >= labelLastLBA) &&
291 // If the end point is 0, it's not a valid partition.
292 if ((sectorEnd == 0) || (sectorEnd == labelFirstLBA))
296 guid.SetFirstLBA(sectorOne);
297 guid.SetLastLBA(sectorEnd);
298 // Now set a random unique GUID for the partition....
299 guid.RandomizeUniqueGUID();
300 // ... zero out the attributes and name fields....
301 guid.SetAttributes(UINT64_C(0));
302 // Most BSD disklabel type codes seem to be archaic or rare.
303 // They're also ambiguous; a FreeBSD filesystem is impossible
304 // to distinguish from a NetBSD one. Thus, these code assignment
305 // are going to be rough to begin with. For a list of meanings,
306 // see http://fxr.watson.org/fxr/source/sys/dtype.h?v=DFBSD,
308 switch (GetType(i)) {
310 guid.SetType(0xa502); break;
312 guid.SetType(0xa503); break;
313 case 8: case 11: // MS-DOS or HPFS
314 guid.SetType(0x0700); break;
315 case 9: // log-structured fs
316 guid.SetType(0xa903); break;
317 case 13: // bootstrap
318 guid.SetType(0xa501); break;
320 guid.SetType(0xa505); break;
322 guid.SetType(0xa903); break;
323 case 27: // FreeBSD ZFS
324 guid.SetType(0xa504); break;
326 guid.SetType(0xa503); break;
328 // Set the partition name to the name of the type code....
329 guid.SetName(guid.GetTypeName());
332 } // BSDData::AsGPT()