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basicmbr.cc
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/* basicmbr.cc -- Functions for loading, saving, and manipulating legacy MBR partition
data. */
/* Initial coding by Rod Smith, January to February, 2009 */
/* This program is copyright (c) 2009-2013 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
#ifndef __STDC_CONSTANT_MACROS
#define __STDC_CONSTANT_MACROS
#endif
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <fcntl.h>
#include <string.h>
#include <time.h>
#include <sys/stat.h>
#include <errno.h>
#include <iostream>
#include <algorithm>
#include "mbr.h"
#include "support.h"
using namespace std;
/****************************************
* *
* MBRData class and related structures *
* *
****************************************/
BasicMBRData::BasicMBRData(void) {
blockSize = SECTOR_SIZE;
diskSize = 0;
device = "";
state = invalid;
numHeads = MAX_HEADS;
numSecspTrack = MAX_SECSPERTRACK;
myDisk = NULL;
canDeleteMyDisk = 0;
// memset(&EbrLocations, 0, MAX_MBR_PARTS * sizeof(uint32_t));
EmptyMBR();
} // BasicMBRData default constructor
BasicMBRData::BasicMBRData(const BasicMBRData & orig) {
int i;
if (&orig != this) {
memcpy(code, orig.code, 440);
diskSignature = orig.diskSignature;
nulls = orig.nulls;
MBRSignature = orig.MBRSignature;
blockSize = orig.blockSize;
diskSize = orig.diskSize;
numHeads = orig.numHeads;
numSecspTrack = orig.numSecspTrack;
canDeleteMyDisk = orig.canDeleteMyDisk;
device = orig.device;
state = orig.state;
myDisk = new DiskIO;
if (myDisk == NULL) {
cerr << "Unable to allocate memory in BasicMBRData copy constructor! Terminating!\n";
exit(1);
} // if
if (orig.myDisk != NULL)
myDisk->OpenForRead(orig.myDisk->GetName());
for (i = 0; i < MAX_MBR_PARTS; i++) {
partitions[i] = orig.partitions[i];
} // for
} // if
} // BasicMBRData copy constructor
BasicMBRData::BasicMBRData(string filename) {
blockSize = SECTOR_SIZE;
diskSize = 0;
device = filename;
state = invalid;
numHeads = MAX_HEADS;
numSecspTrack = MAX_SECSPERTRACK;
myDisk = NULL;
canDeleteMyDisk = 0;
// memset(&EbrLocations, 0, MAX_MBR_PARTS * sizeof(uint32_t));
// Try to read the specified partition table, but if it fails....
if (!ReadMBRData(filename)) {
EmptyMBR();
device = "";
} // if
} // BasicMBRData(string filename) constructor
// Free space used by myDisk only if that's OK -- sometimes it will be
// copied from an outside source, in which case that source should handle
// it!
BasicMBRData::~BasicMBRData(void) {
if (canDeleteMyDisk)
delete myDisk;
} // BasicMBRData destructor
// Assignment operator -- copy entire set of MBR data.
BasicMBRData & BasicMBRData::operator=(const BasicMBRData & orig) {
int i;
if (&orig != this) {
memcpy(code, orig.code, 440);
diskSignature = orig.diskSignature;
nulls = orig.nulls;
MBRSignature = orig.MBRSignature;
blockSize = orig.blockSize;
diskSize = orig.diskSize;
numHeads = orig.numHeads;
numSecspTrack = orig.numSecspTrack;
canDeleteMyDisk = orig.canDeleteMyDisk;
device = orig.device;
state = orig.state;
myDisk = new DiskIO;
if (myDisk == NULL) {
cerr << "Unable to allocate memory in BasicMBRData::operator=()! Terminating!\n";
exit(1);
} // if
if (orig.myDisk != NULL)
myDisk->OpenForRead(orig.myDisk->GetName());
for (i = 0; i < MAX_MBR_PARTS; i++) {
partitions[i] = orig.partitions[i];
} // for
} // if
return *this;
} // BasicMBRData::operator=()
/**********************
* *
* Disk I/O functions *
* *
**********************/
// Read data from MBR. Returns 1 if read was successful (even if the
// data isn't a valid MBR), 0 if the read failed.
int BasicMBRData::ReadMBRData(const string & deviceFilename) {
int allOK = 1;
if (myDisk == NULL) {
myDisk = new DiskIO;
if (myDisk == NULL) {
cerr << "Unable to allocate memory in BasicMBRData::ReadMBRData()! Terminating!\n";
exit(1);
} // if
canDeleteMyDisk = 1;
} // if
if (myDisk->OpenForRead(deviceFilename)) {
allOK = ReadMBRData(myDisk);
} else {
allOK = 0;
} // if
if (allOK)
device = deviceFilename;
return allOK;
} // BasicMBRData::ReadMBRData(const string & deviceFilename)
// Read data from MBR. If checkBlockSize == 1 (the default), the block
// size is checked; otherwise it's set to the default (512 bytes).
// Note that any extended partition(s) present will be omitted from
// in the partitions[] array; these partitions must be re-created when
// the partition table is saved in MBR format.
int BasicMBRData::ReadMBRData(DiskIO * theDisk, int checkBlockSize) {
int allOK = 1, i, logicalNum = 3;
int err = 1;
TempMBR tempMBR;
if ((myDisk != NULL) && (myDisk != theDisk) && (canDeleteMyDisk)) {
delete myDisk;
canDeleteMyDisk = 0;
} // if
myDisk = theDisk;
// Empty existing MBR data, including the logical partitions...
EmptyMBR(0);
if (myDisk->Seek(0))
if (myDisk->Read(&tempMBR, 512))
err = 0;
if (err) {
cerr << "Problem reading disk in BasicMBRData::ReadMBRData()!\n";
} else {
for (i = 0; i < 440; i++)
code[i] = tempMBR.code[i];
diskSignature = tempMBR.diskSignature;
nulls = tempMBR.nulls;
for (i = 0; i < 4; i++) {
partitions[i] = tempMBR.partitions[i];
if (partitions[i].GetLengthLBA() > 0)
partitions[i].SetInclusion(PRIMARY);
} // for i... (reading all four partitions)
MBRSignature = tempMBR.MBRSignature;
ReadCHSGeom();
// Reverse the byte order, if necessary
if (IsLittleEndian() == 0) {
ReverseBytes(&diskSignature, 4);
ReverseBytes(&nulls, 2);
ReverseBytes(&MBRSignature, 2);
for (i = 0; i < 4; i++) {
partitions[i].ReverseByteOrder();
} // for
} // if
if (MBRSignature != MBR_SIGNATURE) {
allOK = 0;
state = invalid;
} // if
// Find disk size
diskSize = myDisk->DiskSize(&err);
// Find block size
if (checkBlockSize) {
blockSize = myDisk->GetBlockSize();
} // if (checkBlockSize)
// Load logical partition data, if any is found....
if (allOK) {
for (i = 0; i < 4; i++) {
if ((partitions[i].GetType() == 0x05) || (partitions[i].GetType() == 0x0f)
|| (partitions[i].GetType() == 0x85)) {
// Found it, so call a function to load everything from them....
logicalNum = ReadLogicalParts(partitions[i].GetStartLBA(), abs(logicalNum) + 1);
if (logicalNum < 0) {
cerr << "Error reading logical partitions! List may be truncated!\n";
} // if maxLogicals valid
DeletePartition(i);
} // if primary partition is extended
} // for primary partition loop
if (allOK) { // Loaded logicals OK
state = mbr;
} else {
state = invalid;
} // if
} // if
// Check to see if it's in GPT format....
if (allOK) {
for (i = 0; i < 4; i++) {
if (partitions[i].GetType() == UINT8_C(0xEE)) {
state = gpt;
} // if
} // for
} // if
// If there's an EFI GPT partition, look for other partition types,
// to flag as hybrid
if (state == gpt) {
for (i = 0 ; i < 4; i++) {
if ((partitions[i].GetType() != UINT8_C(0xEE)) &&
(partitions[i].GetType() != UINT8_C(0x00)))
state = hybrid;
if (logicalNum != 3)
cerr << "Warning! MBR Logical partitions found on a hybrid MBR disk! This is an\n"
<< "EXTREMELY dangerous configuration!\n\a";
} // for
} // if (hybrid detection code)
} // no initial error
return allOK;
} // BasicMBRData::ReadMBRData(DiskIO * theDisk, int checkBlockSize)
// This is a function to read all the logical partitions, following the
// logical partition linked list from the disk and storing the basic data in the
// partitions[] array. Returns last index to partitions[] used, or -1 times the
// that index if there was a problem. (Some problems can leave valid logical
// partition data.)
// Parameters:
// extendedStart = LBA of the start of the extended partition
// partNum = number of first partition in extended partition (normally 4).
int BasicMBRData::ReadLogicalParts(uint64_t extendedStart, int partNum) {
struct TempMBR ebr;
int i, another = 1, allOK = 1;
uint8_t ebrType;
uint64_t offset;
uint64_t EbrLocations[MAX_MBR_PARTS];
offset = extendedStart;
memset(&EbrLocations, 0, MAX_MBR_PARTS * sizeof(uint64_t));
while (another && (partNum < MAX_MBR_PARTS) && (partNum >= 0) && (allOK > 0)) {
for (i = 0; i < MAX_MBR_PARTS; i++) {
if (EbrLocations[i] == offset) { // already read this one; infinite logical partition loop!
cerr << "Logical partition infinite loop detected! This is being corrected.\n";
allOK = -1;
if(partNum > 0) //don't go negative
partNum -= 1;
} // if
} // for
EbrLocations[partNum] = offset;
if (myDisk->Seek(offset) == 0) { // seek to EBR record
cerr << "Unable to seek to " << offset << "! Aborting!\n";
allOK = -1;
}
if (myDisk->Read(&ebr, 512) != 512) { // Load the data....
cerr << "Error seeking to or reading logical partition data from " << offset
<< "!\nSome logical partitions may be missing!\n";
allOK = -1;
} else if (IsLittleEndian() != 1) { // Reverse byte ordering of some data....
ReverseBytes(&ebr.MBRSignature, 2);
ReverseBytes(&ebr.partitions[0].firstLBA, 4);
ReverseBytes(&ebr.partitions[0].lengthLBA, 4);
ReverseBytes(&ebr.partitions[1].firstLBA, 4);
ReverseBytes(&ebr.partitions[1].lengthLBA, 4);
} // if/else/if
if (ebr.MBRSignature != MBR_SIGNATURE) {
allOK = -1;
cerr << "EBR signature for logical partition invalid; read 0x";
cerr.fill('0');
cerr.width(4);
cerr.setf(ios::uppercase);
cerr << hex << ebr.MBRSignature << ", but should be 0x";
cerr.width(4);
cerr << MBR_SIGNATURE << dec << "\n";
cerr.fill(' ');
} // if
if ((partNum >= 0) && (partNum < MAX_MBR_PARTS) && (allOK > 0)) {
// Sometimes an EBR points directly to another EBR, rather than defining
// a logical partition and then pointing to another EBR. Thus, we skip
// the logical partition when this is the case....
ebrType = ebr.partitions[0].partitionType;
if ((ebrType == 0x05) || (ebrType == 0x0f) || (ebrType == 0x85)) {
cout << "EBR points to an EBR!\n";
offset = extendedStart + ebr.partitions[0].firstLBA;
} else {
// Copy over the basic data....
partitions[partNum] = ebr.partitions[0];
// Adjust the start LBA, since it's encoded strangely....
partitions[partNum].SetStartLBA(ebr.partitions[0].firstLBA + offset);
partitions[partNum].SetInclusion(LOGICAL);
// Find the next partition (if there is one)
if ((ebr.partitions[1].firstLBA != UINT32_C(0)) && (partNum < (MAX_MBR_PARTS - 1))) {
offset = extendedStart + ebr.partitions[1].firstLBA;
partNum++;
} else {
another = 0;
} // if another partition
} // if/else
} // if
} // while()
return (partNum * allOK);
} // BasicMBRData::ReadLogicalPart()
// Write the MBR data to the default defined device. This writes both the
// MBR itself and any defined logical partitions, provided there's an
// MBR extended partition.
int BasicMBRData::WriteMBRData(void) {
int allOK = 1;
if (myDisk != NULL) {
if (myDisk->OpenForWrite() != 0) {
allOK = WriteMBRData(myDisk);
cout << "Done writing data!\n";
} else {
allOK = 0;
} // if/else
myDisk->Close();
} else allOK = 0;
return allOK;
} // BasicMBRData::WriteMBRData(void)
// Save the MBR data to a file. This writes both the
// MBR itself and any defined logical partitions.
int BasicMBRData::WriteMBRData(DiskIO *theDisk) {
int i, j, partNum, next, allOK = 1, moreLogicals = 0;
uint64_t extFirstLBA = 0;
uint64_t writeEbrTo; // 64-bit because we support extended in 2-4TiB range
TempMBR tempMBR;
allOK = CreateExtended();
if (allOK) {
// First write the main MBR data structure....
memcpy(tempMBR.code, code, 440);
tempMBR.diskSignature = diskSignature;
tempMBR.nulls = nulls;
tempMBR.MBRSignature = MBRSignature;
for (i = 0; i < 4; i++) {
partitions[i].StoreInStruct(&tempMBR.partitions[i]);
if (partitions[i].GetType() == 0x0f) {
extFirstLBA = partitions[i].GetStartLBA();
moreLogicals = 1;
} // if
} // for i...
} // if
allOK = allOK && WriteMBRData(tempMBR, theDisk, 0);
// Set up tempMBR with some constant data for logical partitions...
tempMBR.diskSignature = 0;
for (i = 2; i < 4; i++) {
tempMBR.partitions[i].firstLBA = tempMBR.partitions[i].lengthLBA = 0;
tempMBR.partitions[i].partitionType = 0x00;
for (j = 0; j < 3; j++) {
tempMBR.partitions[i].firstSector[j] = 0;
tempMBR.partitions[i].lastSector[j] = 0;
} // for j
} // for i
partNum = FindNextInUse(4);
writeEbrTo = (uint64_t) extFirstLBA;
// Write logicals...
while (allOK && moreLogicals && (partNum < MAX_MBR_PARTS) && (partNum >= 0)) {
partitions[partNum].StoreInStruct(&tempMBR.partitions[0]);
tempMBR.partitions[0].firstLBA = 1;
// tempMBR.partitions[1] points to next EBR or terminates EBR linked list...
next = FindNextInUse(partNum + 1);
if ((next < MAX_MBR_PARTS) && (next > 0) && (partitions[next].GetStartLBA() > 0)) {
tempMBR.partitions[1].partitionType = 0x0f;
tempMBR.partitions[1].firstLBA = (uint32_t) (partitions[next].GetStartLBA() - extFirstLBA - 1);
tempMBR.partitions[1].lengthLBA = (uint32_t) (partitions[next].GetLengthLBA() + 1);
LBAtoCHS((uint64_t) tempMBR.partitions[1].firstLBA,
(uint8_t *) &tempMBR.partitions[1].firstSector);
LBAtoCHS(tempMBR.partitions[1].lengthLBA - extFirstLBA,
(uint8_t *) &tempMBR.partitions[1].lastSector);
} else {
tempMBR.partitions[1].partitionType = 0x00;
tempMBR.partitions[1].firstLBA = 0;
tempMBR.partitions[1].lengthLBA = 0;
moreLogicals = 0;
} // if/else
allOK = WriteMBRData(tempMBR, theDisk, writeEbrTo);
writeEbrTo = (uint64_t) tempMBR.partitions[1].firstLBA + (uint64_t) extFirstLBA;
partNum = next;
} // while
DeleteExtendedParts();
return allOK;
} // BasicMBRData::WriteMBRData(DiskIO *theDisk)
int BasicMBRData::WriteMBRData(const string & deviceFilename) {
device = deviceFilename;
return WriteMBRData();
} // BasicMBRData::WriteMBRData(const string & deviceFilename)
// Write a single MBR record to the specified sector. Used by the like-named
// function to write both the MBR and multiple EBR (for logical partition)
// records.
// Returns 1 on success, 0 on failure
int BasicMBRData::WriteMBRData(struct TempMBR & mbr, DiskIO *theDisk, uint64_t sector) {
int i, allOK;
// Reverse the byte order, if necessary
if (IsLittleEndian() == 0) {
ReverseBytes(&mbr.diskSignature, 4);
ReverseBytes(&mbr.nulls, 2);
ReverseBytes(&mbr.MBRSignature, 2);
for (i = 0; i < 4; i++) {
ReverseBytes(&mbr.partitions[i].firstLBA, 4);
ReverseBytes(&mbr.partitions[i].lengthLBA, 4);
} // for
} // if
// Now write the data structure...
allOK = theDisk->OpenForWrite();
if (allOK && theDisk->Seek(sector)) {
if (theDisk->Write(&mbr, 512) != 512) {
allOK = 0;
cerr << "Error " << errno << " when saving MBR!\n";
} // if
} else {
allOK = 0;
cerr << "Error " << errno << " when seeking to MBR to write it!\n";
} // if/else
theDisk->Close();
// Reverse the byte order back, if necessary
if (IsLittleEndian() == 0) {
ReverseBytes(&mbr.diskSignature, 4);
ReverseBytes(&mbr.nulls, 2);
ReverseBytes(&mbr.MBRSignature, 2);
for (i = 0; i < 4; i++) {
ReverseBytes(&mbr.partitions[i].firstLBA, 4);
ReverseBytes(&mbr.partitions[i].lengthLBA, 4);
} // for
}// if
return allOK;
} // BasicMBRData::WriteMBRData(uint64_t sector)
// Set a new disk device; used in copying one disk's partition
// table to another disk.
void BasicMBRData::SetDisk(DiskIO *theDisk) {
int err;
myDisk = theDisk;
diskSize = theDisk->DiskSize(&err);
canDeleteMyDisk = 0;
ReadCHSGeom();
} // BasicMBRData::SetDisk()
/********************************************
* *
* Functions that display data for the user *
* *
********************************************/
// Show the MBR data to the user, up to the specified maximum number
// of partitions....
void BasicMBRData::DisplayMBRData(void) {
int i;
cout << "\nDisk size is " << diskSize << " sectors ("
<< BytesToIeee(diskSize, blockSize) << ")\n";
cout << "MBR disk identifier: 0x";
cout.width(8);
cout.fill('0');
cout.setf(ios::uppercase);
cout << hex << diskSignature << dec << "\n";
cout << "MBR partitions:\n\n";
if ((state == gpt) || (state == hybrid)) {
cout << "Number Boot Start Sector End Sector Status Code\n";
} else {
cout << " Can Be Can Be\n";
cout << "Number Boot Start Sector End Sector Status Logical Primary Code\n";
UpdateCanBeLogical();
} //
for (i = 0; i < MAX_MBR_PARTS; i++) {
if (partitions[i].GetLengthLBA() != 0) {
cout.fill(' ');
cout.width(4);
cout << i + 1 << " ";
partitions[i].ShowData((state == gpt) || (state == hybrid));
} // if
cout.fill(' ');
} // for
} // BasicMBRData::DisplayMBRData()
// Displays the state, as a word, on stdout. Used for debugging & to
// tell the user about the MBR state when the program launches....
void BasicMBRData::ShowState(void) {
switch (state) {
case invalid:
cout << " MBR: not present\n";
break;
case gpt:
cout << " MBR: protective\n";
break;
case hybrid:
cout << " MBR: hybrid\n";
break;
case mbr:
cout << " MBR: MBR only\n";
break;
default:
cout << "\a MBR: unknown -- bug!\n";
break;
} // switch
} // BasicMBRData::ShowState()
/************************
* *
* GPT Checks and fixes *
* *
************************/
// Perform a very rudimentary check for GPT data on the disk; searches for
// the GPT signature in the main and backup metadata areas.
// Returns 0 if GPT data not found, 1 if main data only is found, 2 if
// backup only is found, 3 if both main and backup data are found, and
// -1 if a disk error occurred.
int BasicMBRData::CheckForGPT(void) {
int retval = 0, err;
char signature1[9], signature2[9];
if (myDisk != NULL) {
if (myDisk->OpenForRead() != 0) {
if (myDisk->Seek(1)) {
myDisk->Read(signature1, 8);
signature1[8] = '\0';
} else retval = -1;
if (myDisk->Seek(myDisk->DiskSize(&err) - 1)) {
myDisk->Read(signature2, 8);
signature2[8] = '\0';
} else retval = -1;
if ((retval >= 0) && (strcmp(signature1, "EFI PART") == 0))
retval += 1;
if ((retval >= 0) && (strcmp(signature2, "EFI PART") == 0))
retval += 2;
} else {
retval = -1;
} // if/else
myDisk->Close();
} else retval = -1;
return retval;
} // BasicMBRData::CheckForGPT()
// Blanks the 2nd (sector #1, numbered from 0) and last sectors of the disk,
// but only if GPT data are verified on the disk, and only for the sector(s)
// with GPT signatures.
// Returns 1 if operation completes successfully, 0 if not (returns 1 if
// no GPT data are found on the disk).
int BasicMBRData::BlankGPTData(void) {
int allOK = 1, err;
uint8_t blank[512];
memset(blank, 0, 512);
switch (CheckForGPT()) {
case -1:
allOK = 0;
break;
case 0:
break;
case 1:
if ((myDisk != NULL) && (myDisk->OpenForWrite())) {
if (!((myDisk->Seek(1)) && (myDisk->Write(blank, 512) == 512)))
allOK = 0;
myDisk->Close();
} else allOK = 0;
break;
case 2:
if ((myDisk != NULL) && (myDisk->OpenForWrite())) {
if (!((myDisk->Seek(myDisk->DiskSize(&err) - 1)) &&
(myDisk->Write(blank, 512) == 512)))
allOK = 0;
myDisk->Close();
} else allOK = 0;
break;
case 3:
if ((myDisk != NULL) && (myDisk->OpenForWrite())) {
if (!((myDisk->Seek(1)) && (myDisk->Write(blank, 512) == 512)))
allOK = 0;
if (!((myDisk->Seek(myDisk->DiskSize(&err) - 1)) &&
(myDisk->Write(blank, 512) == 512)))
allOK = 0;
myDisk->Close();
} else allOK = 0;
break;
default:
break;
} // switch()
return allOK;
} // BasicMBRData::BlankGPTData
/*********************************************************************
* *
* Functions that set or get disk metadata (CHS geometry, disk size, *
* etc.) *
* *
*********************************************************************/
// Read the CHS geometry using OS calls, or if that fails, set to
// the most common value for big disks (255 heads, 63 sectors per
// track, & however many cylinders that computes to).
void BasicMBRData::ReadCHSGeom(void) {
int err;
numHeads = myDisk->GetNumHeads();
numSecspTrack = myDisk->GetNumSecsPerTrack();
diskSize = myDisk->DiskSize(&err);
blockSize = myDisk->GetBlockSize();
partitions[0].SetGeometry(numHeads, numSecspTrack, diskSize, blockSize);
} // BasicMBRData::ReadCHSGeom()
// Find the low and high used partition numbers (numbered from 0).
// Return value is the number of partitions found. Note that the
// *low and *high values are both set to 0 when no partitions
// are found, as well as when a single partition in the first
// position exists. Thus, the return value is the only way to
// tell when no partitions exist.
int BasicMBRData::GetPartRange(uint32_t *low, uint32_t *high) {
uint32_t i;
int numFound = 0;
*low = MAX_MBR_PARTS + 1; // code for "not found"
*high = 0;
for (i = 0; i < MAX_MBR_PARTS; i++) {
if (partitions[i].GetStartLBA() != UINT32_C(0)) { // it exists
*high = i; // since we're counting up, set the high value
// Set the low value only if it's not yet found...
if (*low == (MAX_MBR_PARTS + 1))
*low = i;
numFound++;
} // if
} // for
// Above will leave *low pointing to its "not found" value if no partitions
// are defined, so reset to 0 if this is the case....
if (*low == (MAX_MBR_PARTS + 1))
*low = 0;
return numFound;
} // GPTData::GetPartRange()
// Converts 64-bit LBA value to MBR-style CHS value. Returns 1 if conversion
// was within the range that can be expressed by CHS (including 0, for an
// empty partition), 0 if the value is outside that range, and -1 if chs is
// invalid.
int BasicMBRData::LBAtoCHS(uint64_t lba, uint8_t * chs) {
uint64_t cylinder, head, sector; // all numbered from 0
uint64_t remainder;
int retval = 1;
int done = 0;
if (chs != NULL) {
// Special case: In case of 0 LBA value, zero out CHS values....
if (lba == 0) {
chs[0] = chs[1] = chs[2] = UINT8_C(0);
done = 1;
} // if
// If LBA value is too large for CHS, max out CHS values....
if ((!done) && (lba >= ((uint64_t) numHeads * numSecspTrack * MAX_CYLINDERS))) {
chs[0] = 254;
chs[1] = chs[2] = 255;
done = 1;
retval = 0;
} // if
// If neither of the above applies, compute CHS values....
if (!done) {
cylinder = lba / (uint64_t) (numHeads * numSecspTrack);
remainder = lba - (cylinder * numHeads * numSecspTrack);
head = remainder / numSecspTrack;
remainder -= head * numSecspTrack;
sector = remainder;
if (head < numHeads)
chs[0] = (uint8_t) head;
else
retval = 0;
if (sector < numSecspTrack) {
chs[1] = (uint8_t) ((sector + 1) + (cylinder >> 8) * 64);
chs[2] = (uint8_t) (cylinder & UINT64_C(0xFF));
} else {
retval = 0;
} // if/else
} // if value is expressible and non-0
} else { // Invalid (NULL) chs pointer
retval = -1;
} // if CHS pointer valid
return (retval);
} // BasicMBRData::LBAtoCHS()
// Look for overlapping partitions. Also looks for a couple of non-error
// conditions that the user should be told about.
// Returns the number of problems found
int BasicMBRData::FindOverlaps(void) {
int i, j, numProbs = 0, numEE = 0, ProtectiveOnOne = 0;
for (i = 0; i < MAX_MBR_PARTS; i++) {
for (j = i + 1; j < MAX_MBR_PARTS; j++) {
if ((partitions[i].GetInclusion() != NONE) && (partitions[j].GetInclusion() != NONE) &&
(partitions[i].DoTheyOverlap(partitions[j]))) {
numProbs++;
cout << "\nProblem: MBR partitions " << i + 1 << " and " << j + 1
<< " overlap!\n";
} // if
} // for (j...)
if (partitions[i].GetType() == 0xEE) {
numEE++;
if (partitions[i].GetStartLBA() == 1)
ProtectiveOnOne = 1;
} // if
} // for (i...)
if (numEE > 1)
cout << "\nCaution: More than one 0xEE MBR partition found. This can cause problems\n"
<< "in some OSes.\n";
if (!ProtectiveOnOne && (numEE > 0))
cout << "\nWarning: 0xEE partition doesn't start on sector 1. This can cause "
<< "problems\nin some OSes.\n";
return numProbs;
} // BasicMBRData::FindOverlaps()
// Returns the number of primary partitions, including the extended partition
// required to hold any logical partitions found.
int BasicMBRData::NumPrimaries(void) {
int i, numPrimaries = 0, logicalsFound = 0;
for (i = 0; i < MAX_MBR_PARTS; i++) {
if (partitions[i].GetLengthLBA() > 0) {
if (partitions[i].GetInclusion() == PRIMARY)
numPrimaries++;
if (partitions[i].GetInclusion() == LOGICAL)
logicalsFound = 1;
} // if
} // for
return (numPrimaries + logicalsFound);
} // BasicMBRData::NumPrimaries()
// Returns the number of logical partitions.
int BasicMBRData::NumLogicals(void) {
int i, numLogicals = 0;
for (i = 0; i < MAX_MBR_PARTS; i++) {
if (partitions[i].GetInclusion() == LOGICAL)
numLogicals++;
} // for
return numLogicals;
} // BasicMBRData::NumLogicals()
// Returns the number of partitions (primaries plus logicals), NOT including
// the extended partition required to house the logicals.
int BasicMBRData::CountParts(void) {
int i, num = 0;
for (i = 0; i < MAX_MBR_PARTS; i++) {
if ((partitions[i].GetInclusion() == LOGICAL) ||
(partitions[i].GetInclusion() == PRIMARY))
num++;
} // for
return num;
} // BasicMBRData::CountParts()
// Updates the canBeLogical and canBePrimary flags for all the partitions.
void BasicMBRData::UpdateCanBeLogical(void) {
int i, j, sectorBefore, numPrimaries, numLogicals, usedAsEBR;
uint64_t firstLogical, lastLogical, lStart, pStart;
numPrimaries = NumPrimaries();
numLogicals = NumLogicals();
firstLogical = FirstLogicalLBA() - 1;
lastLogical = LastLogicalLBA();
for (i = 0; i < MAX_MBR_PARTS; i++) {
usedAsEBR = (SectorUsedAs(partitions[i].GetLastLBA()) == EBR);
if (usedAsEBR) {
partitions[i].SetCanBeLogical(0);
partitions[i].SetCanBePrimary(0);
} else if (partitions[i].GetLengthLBA() > 0) {
// First determine if it can be logical....
sectorBefore = SectorUsedAs(partitions[i].GetStartLBA() - 1);
lStart = partitions[i].GetStartLBA(); // start of potential logical part.
if ((lastLogical > 0) &&
((sectorBefore == EBR) || (sectorBefore == NONE))) {
// Assume it can be logical, then search for primaries that make it
// not work and, if found, flag appropriately.
partitions[i].SetCanBeLogical(1);
for (j = 0; j < MAX_MBR_PARTS; j++) {
if ((i != j) && (partitions[j].GetInclusion() == PRIMARY)) {
pStart = partitions[j].GetStartLBA();
if (((pStart < lStart) && (firstLogical < pStart)) ||
((pStart > lStart) && (firstLogical > pStart))) {
partitions[i].SetCanBeLogical(0);
} // if/else
} // if
} // for
} else {
if ((sectorBefore != EBR) && (sectorBefore != NONE))
partitions[i].SetCanBeLogical(0);
else
partitions[i].SetCanBeLogical(lastLogical == 0); // can be logical only if no logicals already
} // if/else
// Now determine if it can be primary. Start by assuming it can be...
partitions[i].SetCanBePrimary(1);
if ((numPrimaries >= 4) && (partitions[i].GetInclusion() != PRIMARY)) {
partitions[i].SetCanBePrimary(0);
if ((partitions[i].GetInclusion() == LOGICAL) && (numLogicals == 1) &&
(numPrimaries == 4))
partitions[i].SetCanBePrimary(1);
} // if
if ((partitions[i].GetStartLBA() > (firstLogical + 1)) &&
(partitions[i].GetLastLBA() < lastLogical))
partitions[i].SetCanBePrimary(0);
} // else if
} // for
} // BasicMBRData::UpdateCanBeLogical()
// Returns the first sector occupied by any logical partition. Note that
// this does NOT include the logical partition's EBR! Returns UINT32_MAX
// if there are no logical partitions defined.
uint64_t BasicMBRData::FirstLogicalLBA(void) {
int i;
uint64_t firstFound = UINT32_MAX;
for (i = 0; i < MAX_MBR_PARTS; i++) {
if ((partitions[i].GetInclusion() == LOGICAL) &&
(partitions[i].GetStartLBA() < firstFound)) {
firstFound = partitions[i].GetStartLBA();
} // if
} // for
return firstFound;
} // BasicMBRData::FirstLogicalLBA()
// Returns the last sector occupied by any logical partition, or 0 if
// there are no logical partitions defined.
uint64_t BasicMBRData::LastLogicalLBA(void) {
int i;
uint64_t lastFound = 0;
for (i = 0; i < MAX_MBR_PARTS; i++) {
if ((partitions[i].GetInclusion() == LOGICAL) &&
(partitions[i].GetLastLBA() > lastFound))
lastFound = partitions[i].GetLastLBA();
} // for
return lastFound;
} // BasicMBRData::LastLogicalLBA()
// Returns 1 if logical partitions are contiguous (have no primaries
// in their midst), or 0 if one or more primaries exist between
// logicals.
int BasicMBRData::AreLogicalsContiguous(void) {
int allOK = 1, i = 0;
uint64_t firstLogical, lastLogical;
firstLogical = FirstLogicalLBA() - 1; // subtract 1 for EBR
lastLogical = LastLogicalLBA();
if (lastLogical > 0) {
do {
if ((partitions[i].GetInclusion() == PRIMARY) &&
(partitions[i].GetStartLBA() >= firstLogical) &&
(partitions[i].GetStartLBA() <= lastLogical)) {
allOK = 0;
} // if
i++;
} while ((i < MAX_MBR_PARTS) && allOK);
} // if
return allOK;
} // BasicMBRData::AreLogicalsContiguous()
// Returns 1 if all partitions fit on the disk, given its size; 0 if any
// partition is too big.
int BasicMBRData::DoTheyFit(void) {
int i, allOK = 1;
for (i = 0; i < MAX_MBR_PARTS; i++) {
if ((partitions[i].GetStartLBA() > diskSize) || (partitions[i].GetLastLBA() > diskSize)) {
allOK = 0;
} // if
} // for
return allOK;
} // BasicMBRData::DoTheyFit(void)
// Returns 1 if there's at least one free sector immediately preceding
// all partitions flagged as logical; 0 if any logical partition lacks
// this space.
int BasicMBRData::SpaceBeforeAllLogicals(void) {
int i = 0, allOK = 1;
do {
if ((partitions[i].GetStartLBA() > 0) && (partitions[i].GetInclusion() == LOGICAL)) {
allOK = allOK && (SectorUsedAs(partitions[i].GetStartLBA() - 1) == EBR);
} // if
i++;
} while (allOK && (i < MAX_MBR_PARTS));
return allOK;
} // BasicMBRData::SpaceBeforeAllLogicals()
// Returns 1 if the partitions describe a legal layout -- all logicals
// are contiguous and have at least one preceding empty sector,
// the number of primaries is under 4 (or under 3 if there are any
// logicals), there are no overlapping partitions, etc.
// Does NOT assume that primaries are numbered 1-4; uses the
// IsItPrimary() function of the MBRPart class to determine
// primary status. Also does NOT consider partition order; there
// can be gaps and it will still be considered legal.
int BasicMBRData::IsLegal(void) {
int allOK = 1;
allOK = (FindOverlaps() == 0);
allOK = (allOK && (NumPrimaries() <= 4));
allOK = (allOK && AreLogicalsContiguous());
allOK = (allOK && DoTheyFit());
allOK = (allOK && SpaceBeforeAllLogicals());
return allOK;
} // BasicMBRData::IsLegal()
// Returns 1 if the 0xEE partition in the protective/hybrid MBR is marked as
// active/bootable.
int BasicMBRData::IsEEActive(void) {
int i, IsActive = 0;
for (i = 0; i < MAX_MBR_PARTS; i++) {
if ((partitions[i].GetStatus() & 0x80) && (partitions[i].GetType() == 0xEE))
IsActive = 1;
}
return IsActive;
} // BasicMBRData::IsEEActive()
// Finds the next in-use partition, starting with start (will return start
// if it's in use). Returns -1 if no subsequent partition is in use.
int BasicMBRData::FindNextInUse(int start) {
if (start >= MAX_MBR_PARTS)
start = -1;
while ((start < MAX_MBR_PARTS) && (start >= 0) && (partitions[start].GetInclusion() == NONE))
start++;
if ((start < 0) || (start >= MAX_MBR_PARTS))
start = -1;
return start;
} // BasicMBRData::FindFirstLogical();
/*****************************************************
* *
* Functions to create, delete, or change partitions *
* *
*****************************************************/
// Empty all data. Meant mainly for calling by constructors, but it's also
// used by the hybrid MBR functions in the GPTData class.
void BasicMBRData::EmptyMBR(int clearBootloader) {
int i;
// Zero out the boot loader section, the disk signature, and the
// 2-byte nulls area only if requested to do so. (This is the
// default.)