/* bsd.cc -- Functions for loading and manipulating legacy BSD disklabel

   data. */

/* By Rod Smith, initial coding August, 2009 */

/* This program is copyright (c) 2009 by Roderick W. Smith. It is distributed

  under the terms of the GNU GPL version 2, as detailed in the COPYING file. */

#define __STDC_LIMIT_MACROS

#define __STDC_CONSTANT_MACROS

#include <stdio.h>

//#include <unistd.h>

#include <stdlib.h>

#include <stdint.h>

#include <fcntl.h>

#include <sys/stat.h>

#include <errno.h>

#include <iostream>

#include <string>

#include "support.h"

#include "bsd.h"

using namespace std;

BSDData::BSDData(void) {

   state = unknown;

   signature = UINT32_C(0);

   signature2 = UINT32_C(0);

   sectorSize = 512;

   numParts = 0;

   labelFirstLBA = 0;

   labelLastLBA = 0;

   labelStart = LABEL_OFFSET1; // assume raw disk format

   partitions = NULL;

} // default constructor

BSDData::~BSDData(void) {

   delete[] partitions;

} // destructor

// Read BSD disklabel data from the specified device filename. This function

// just opens the device file and then calls an overloaded function to do

// the bulk of the work. Returns 1 on success, 0 on failure.

int BSDData::ReadBSDData(const string & device, uint64_t startSector, uint64_t endSector) {

   int allOK = 1;

   DiskIO myDisk;

   if (device != "") {

      if (myDisk.OpenForRead(device)) {

         allOK = ReadBSDData(&myDisk, startSector, endSector);

      } else {

         allOK = 0;

      } // if/else

      myDisk.Close();

   } else {

      allOK = 0;

   } // if/else

   return allOK;

} // BSDData::ReadBSDData() (device filename version)

// Load the BSD disklabel data from an already-opened disk

// file, starting with the specified sector number.

int BSDData::ReadBSDData(DiskIO *theDisk, uint64_t startSector, uint64_t endSector) {

   int allOK = 1;

   int i, foundSig = 0, bigEnd = 0;

   int relative = 0; // assume absolute partition sector numbering

   uint8_t buffer[4096]; // I/O buffer

   uint32_t realSig;

   uint32_t* temp32;

   uint16_t* temp16;

   BSDRecord* tempRecords;

   int offset[NUM_OFFSETS] = { LABEL_OFFSET1, LABEL_OFFSET2 };

   labelFirstLBA = startSector;

   labelLastLBA = endSector;

   offset[1] = theDisk->GetBlockSize();

   // Read 4096 bytes (eight 512-byte sectors or equivalent)

   // into memory; we'll extract data from this buffer.

   // (Done to work around FreeBSD limitation on size of reads

   // from block devices.)

   allOK = theDisk->Seek(startSector);

   if (allOK) allOK = theDisk->Read(buffer, 4096);

   // Do some strangeness to support big-endian architectures...

   bigEnd = (IsLittleEndian() == 0);

   realSig = BSD_SIGNATURE;

   if (bigEnd && allOK)

      ReverseBytes(&realSig, 4);

   // Look for the signature at any of two locations.

   // Note that the signature is repeated at both the original

   // offset and 132 bytes later, so we need two checks....

   if (allOK) {

      i = 0;

      do {

         temp32 = (uint32_t*) &buffer[offset[i]];

         signature = *temp32;

         if (signature == realSig) { // found first, look for second

            temp32 = (uint32_t*) &buffer[offset[i] + 132];

            signature2 = *temp32;

            if (signature2 == realSig) {

               foundSig = 1;

               labelStart = offset[i];

            } // if found signature

         } // if/else

         i++;

      } while ((!foundSig) && (i < NUM_OFFSETS));

      allOK = foundSig;

   } // if

   // Load partition metadata from the buffer....

   if (allOK) {

      temp32 = (uint32_t*) &buffer[labelStart + 40];

      sectorSize = *temp32;

      temp16 = (uint16_t*) &buffer[labelStart + 138];

      numParts = *temp16;

   } // if

   // Make it big-endian-aware....

   if ((IsLittleEndian() == 0) && allOK)

      ReverseMetaBytes();

   // Check validity of the data and flag it appropriately....

   if (foundSig && (numParts <= MAX_BSD_PARTS) && allOK) {

      state = bsd;

   } else {

      state = bsd_invalid;

   } // if/else

   // If the state is good, go ahead and load the main partition data....

   if (state == bsd) {

      partitions = new struct BSDRecord[numParts * sizeof(struct BSDRecord)];

      if (partitions == NULL) {

         cerr << "Unable to allocate memory in BSDData::ReadBSDData()! Terminating!\n";

         exit(1);

      } // if

      for (i = 0; i < numParts; i++) {

         // Once again, we use the buffer, but index it using a BSDRecord

         // pointer (dangerous, but effective)....

         tempRecords = (BSDRecord*) &buffer[labelStart + 148];

         partitions[i].lengthLBA = tempRecords[i].lengthLBA;

         partitions[i].firstLBA = tempRecords[i].firstLBA;

         partitions[i].fsType = tempRecords[i].fsType;

         if (bigEnd) { // reverse data (fsType is a single byte)

            ReverseBytes(&partitions[i].lengthLBA, 4);

            ReverseBytes(&partitions[i].firstLBA, 4);

         } // if big-endian

         // Check for signs of relative sector numbering: A "0" first sector

         // number on a partition with a non-zero length -- but ONLY if the

         // length is less than the disk size, since NetBSD has a habit of

         // creating a disk-sized partition within a carrier MBR partition

         // that's too small to house it, and this throws off everything....

         if ((partitions[i].firstLBA == 0) && (partitions[i].lengthLBA > 0)

             && (partitions[i].lengthLBA < labelLastLBA))

            relative = 1;

      } // for

      // Some disklabels use sector numbers relative to the enclosing partition's

      // start, others use absolute sector numbers. If relative numbering was

      // detected above, apply a correction to all partition start sectors....

      if (relative) {

         for (i = 0; i < numParts; i++) {

            partitions[i].firstLBA += (uint32_t) startSector;

         } // for

      } // if

   } // if signatures OK

//   DisplayBSDData();

   return allOK;

} // BSDData::ReadBSDData(DiskIO* theDisk, uint64_t startSector)

// Reverse metadata's byte order; called only on big-endian systems

void BSDData::ReverseMetaBytes(void) {

   ReverseBytes(&signature, 4);

   ReverseBytes(&sectorSize, 4);

   ReverseBytes(&signature2, 4);

   ReverseBytes(&numParts, 2);

} // BSDData::ReverseMetaByteOrder()

// Display basic BSD partition data. Used for debugging.

void BSDData::DisplayBSDData(void) {

   int i;

   if (state == bsd) {

      cout << "BSD partitions:\n";

      for (i = 0; i < numParts; i++) {

         cout.width(4);

         cout << i + 1 << "\t";

         cout.width(13);

         cout << partitions[i].firstLBA << "\t";

         cout.width(15);

         cout << partitions[i].lengthLBA << " \t0x";

         cout.width(2);

         cout.fill('0');

         cout.setf(ios::uppercase);

         cout << hex << (int) partitions[i].fsType << "\n" << dec;

         cout.fill(' ');

      } // for

   } // if

} // BSDData::DisplayBSDData()

// Displays the BSD disklabel state. Called during program launch to inform

// the user about the partition table(s) status

int BSDData::ShowState(void) {

   int retval = 0;

   switch (state) {

      case bsd_invalid:

         cout << "  BSD: not present\n";

         break;

      case bsd:

         cout << "  BSD: present\n";

         retval = 1;

         break;

      default:

         cout << "\a  BSD: unknown -- bug!\n";

         break;

   } // switch

   return retval;

} // BSDData::ShowState()

// Weirdly, this function has stopped working when defined inline,

// but it's OK here....

int BSDData::IsDisklabel(void) {

   return (state == bsd);

} // BSDData::IsDiskLabel()

// Returns the BSD table's partition type code

uint8_t BSDData::GetType(int i) {

   uint8_t retval = 0; // 0 = "unused"

   if ((i < numParts) && (i >= 0) && (state == bsd) && (partitions != 0))

      retval = partitions[i].fsType;

   return(retval);

} // BSDData::GetType()

// Returns the number of the first sector of the specified partition

uint64_t BSDData::GetFirstSector(int i) {

   uint64_t retval = UINT64_C(0);

   if ((i < numParts) && (i >= 0) && (state == bsd) && (partitions != 0))

      retval = (uint64_t) partitions[i].firstLBA;

   return retval;

} // BSDData::GetFirstSector

// Returns the length (in sectors) of the specified partition

uint64_t BSDData::GetLength(int i) {

   uint64_t retval = UINT64_C(0);

   if ((i < numParts) && (i >= 0) && (state == bsd) && (partitions != 0))

      retval = (uint64_t) partitions[i].lengthLBA;

   return retval;

} // BSDData::GetLength()

// Returns the number of partitions defined in the current table

int BSDData::GetNumParts(void) {

   return numParts;

} // BSDData::GetNumParts()

// Returns the specified partition as a GPT partition. Used in BSD-to-GPT

// conversion process

GPTPart BSDData::AsGPT(int i) {

   GPTPart guid;                  // dump data in here, then return it

   uint64_t sectorOne, sectorEnd; // first & last sectors of partition

   int passItOn = 1;              // Set to 0 if partition is empty or invalid

   guid.BlankPartition();

   sectorOne = (uint64_t) partitions[i].firstLBA;

   sectorEnd = sectorOne + (uint64_t) partitions[i].lengthLBA;

   if (sectorEnd > 0) sectorEnd--;

   // Note on above: BSD partitions sometimes have a length of 0 and a start

   // sector of 0. With unsigned ints, the usual way (start + length - 1) to

   // find the end will result in a huge number, which will be confusing.

   // Thus, apply the "-1" part only if it's reasonable to do so.

   // Do a few sanity checks on the partition before we pass it on....

   // First, check that it falls within the bounds of its container

   // and that it starts before it ends....

   if ((sectorOne < labelFirstLBA) || (sectorEnd > labelLastLBA) || (sectorOne > sectorEnd))

      passItOn = 0;

   // Some disklabels include a pseudo-partition that's the size of the entire

   // disk or containing partition. Don't return it.

   if ((sectorOne <= labelFirstLBA) && (sectorEnd >= labelLastLBA) &&

       (GetType(i) == 0))

      passItOn = 0;

   // If the end point is 0, it's not a valid partition.

   if ((sectorEnd == 0) || (sectorEnd == labelFirstLBA))

      passItOn = 0;

   if (passItOn) {

      guid.SetFirstLBA(sectorOne);

      guid.SetLastLBA(sectorEnd);

      // Now set a random unique GUID for the partition....

      guid.RandomizeUniqueGUID();

      // ... zero out the attributes and name fields....

      guid.SetAttributes(UINT64_C(0));

      // Most BSD disklabel type codes seem to be archaic or rare.

      // They're also ambiguous; a FreeBSD filesystem is impossible

      // to distinguish from a NetBSD one. Thus, these code assignment

      // are going to be rough to begin with. For a list of meanings,

      // see http://fxr.watson.org/fxr/source/sys/dtype.h?v=DFBSD,

      // or Google it.

      switch (GetType(i)) {

         case 1: // BSD swap

            guid.SetType(0xa502); break;

         case 7: // BSD FFS

            guid.SetType(0xa503); break;

         case 8: case 11: // MS-DOS or HPFS

            guid.SetType(0x0700); break;

         case 9: // log-structured fs

            guid.SetType(0xa903); break;

         case 13: // bootstrap

            guid.SetType(0xa501); break;

         case 14: // vinum

            guid.SetType(0xa505); break;

         case 15: // RAID

            guid.SetType(0xa903); break;

         case 27: // FreeBSD ZFS

            guid.SetType(0xa504); break;

         default:

            guid.SetType(0xa503); break;

      } // switch

      // Set the partition name to the name of the type code....

      guid.SetName(guid.GetTypeName());

   } // if

   return guid;

} // BSDData::AsGPT()