1 /* mbr.cc -- Functions for loading, saving, and manipulating legacy MBR partition
2 data. */
3
4 /* Initial coding by Rod Smith, January to February, 2009 */
5
6 /* This program is copyright (c) 2009-2013 by Roderick W. Smith. It is distributed
7 under the terms of the GNU GPL version 2, as detailed in the COPYING file. */
8
9 #define __STDC_LIMIT_MACROS
10 #ifndef __STDC_CONSTANT_MACROS
11 #define __STDC_CONSTANT_MACROS
12 #endif
13
14 #include <stdio.h>
15 #include <stdlib.h>
16 #include <stdint.h>
17 #include <fcntl.h>
18 #include <string.h>
19 #include <time.h>
20 #include <sys/stat.h>
21 #include <errno.h>
22 #include <iostream>
23 #include "mbr.h"
24
25 using namespace std;
26
27 /****************************************
28 * *
29 * MBRData class and related structures *
30 * *
31 ****************************************/
32
~MBRData(void)33 MBRData::~MBRData(void) {
34 } // MBRData destructor
35
36 // Assignment operator -- copy entire set of MBR data.
operator =(const BasicMBRData & orig)37 MBRData & MBRData::operator=(const BasicMBRData & orig) {
38 BasicMBRData::operator=(orig);
39 return *this;
40 } // MBRData::operator=()
41
42 /*****************************************************
43 * *
44 * Functions to create, delete, or change partitions *
45 * *
46 *****************************************************/
47
48 // Create a protective MBR. Clears the boot loader area if clearBoot > 0.
MakeProtectiveMBR(int clearBoot)49 void MBRData::MakeProtectiveMBR(int clearBoot) {
50
51 EmptyMBR(clearBoot);
52
53 // Initialize variables
54 nulls = 0;
55 MBRSignature = MBR_SIGNATURE;
56 diskSignature = UINT32_C(0);
57
58 partitions[0].SetStatus(0); // Flag the protective part. as unbootable
59
60 partitions[0].SetType(UINT8_C(0xEE));
61 if (diskSize < UINT32_MAX) { // If the disk is under 2TiB
62 partitions[0].SetLocation(UINT32_C(1), (uint32_t) diskSize - UINT32_C(1));
63 } else { // disk is too big to represent, so fake it...
64 partitions[0].SetLocation(UINT32_C(1), UINT32_MAX);
65 } // if/else
66 partitions[0].SetInclusion(PRIMARY);
67
68 state = gpt;
69 } // MBRData::MakeProtectiveMBR()
70
71 // Optimizes the size of the 0xEE (EFI GPT) partition
OptimizeEESize(void)72 void MBRData::OptimizeEESize(void) {
73 int i, typeFlag = 0;
74 uint64_t after;
75
76 for (i = 0; i < 4; i++) {
77 // Check for non-empty and non-0xEE partitions
78 if ((partitions[i].GetType() != 0xEE) && (partitions[i].GetType() != 0x00))
79 typeFlag++;
80 if (partitions[i].GetType() == 0xEE) {
81 // Blank space before this partition; fill it....
82 if (SectorUsedAs(partitions[i].GetStartLBA() - 1, 4) == NONE) {
83 partitions[i].SetStartLBA(FindFirstInFree(partitions[i].GetStartLBA() - 1));
84 } // if
85 // Blank space after this partition; fill it....
86 after = partitions[i].GetStartLBA() + partitions[i].GetLengthLBA();
87 if (SectorUsedAs(after, 4) == NONE) {
88 partitions[i].SetLengthLBA(FindLastInFree(after) - partitions[i].GetStartLBA() + 1);
89 } // if free space after
90 if (after > diskSize) {
91 if (diskSize < UINT32_MAX) { // If the disk is under 2TiB
92 partitions[i].SetLengthLBA((uint32_t) diskSize - partitions[i].GetStartLBA());
93 } else { // disk is too big to represent, so fake it...
94 partitions[i].SetLengthLBA(UINT32_MAX - partitions[i].GetStartLBA());
95 } // if/else
96 } // if protective partition is too big
97 RecomputeCHS(i);
98 } // if partition is 0xEE
99 } // for partition loop
100 if (typeFlag == 0) { // No non-hybrid partitions found
101 MakeProtectiveMBR(); // ensure it's a fully compliant protective MBR.
102 } // if
103 } // MBRData::OptimizeEESize()
104
105 // Delete a partition if one exists at the specified location.
106 // Returns 1 if a partition was deleted, 0 otherwise....
107 // Used to help keep GPT & hybrid MBR partitions in sync....
DeleteByLocation(uint64_t start64,uint64_t length64)108 int MBRData::DeleteByLocation(uint64_t start64, uint64_t length64) {
109 uint32_t start32, length32;
110 int i, deleted = 0;
111
112 if ((start64 < UINT32_MAX) && (length64 < UINT32_MAX)) {
113 start32 = (uint32_t) start64;
114 length32 = (uint32_t) length64;
115 for (i = 0; i < MAX_MBR_PARTS; i++) {
116 if ((partitions[i].GetType() != 0xEE) && (partitions[i].GetStartLBA() == start32)
117 && (partitions[i].GetLengthLBA() == length32)) {
118 DeletePartition(i);
119 if (state == hybrid)
120 OptimizeEESize();
121 deleted = 1;
122 } // if (match found)
123 } // for i (partition scan)
124 } // if (hybrid & GPT partition < 2TiB)
125 return deleted;
126 } // MBRData::DeleteByLocation()
127
128 /******************************************************
129 * *
130 * Functions that extract data on specific partitions *
131 * *
132 ******************************************************/
133
134 // Return the MBR data as a GPT partition....
AsGPT(int i)135 GPTPart MBRData::AsGPT(int i) {
136 MBRPart* origPart;
137 GPTPart newPart;
138 uint8_t origType;
139 uint64_t firstSector, lastSector;
140
141 newPart.BlankPartition();
142 origPart = GetPartition(i);
143 if (origPart != NULL) {
144 origType = origPart->GetType();
145
146 // don't convert extended, hybrid protective, or null (non-existent)
147 // partitions (Note similar protection is in GPTData::XFormPartitions(),
148 // but I want it here too in case I call this function in another
149 // context in the future....)
150 if ((origType != 0x05) && (origType != 0x0f) && (origType != 0x85) &&
151 (origType != 0x00) && (origType != 0xEE)) {
152 firstSector = (uint64_t) origPart->GetStartLBA();
153 newPart.SetFirstLBA(firstSector);
154 lastSector = (uint64_t) origPart->GetLastLBA();
155 newPart.SetLastLBA(lastSector);
156 newPart.SetType(((uint16_t) origType) * 0x0100);
157 newPart.RandomizeUniqueGUID();
158 newPart.SetAttributes(0);
159 newPart.SetName(newPart.GetTypeName());
160 } // if not extended, protective, or non-existent
161 } // if (origPart != NULL)
162 return newPart;
163 } // MBRData::AsGPT()
164
165