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 #define __STDC_CONSTANT_MACROS
11
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <stdint.h>
15 #include <fcntl.h>
16 #include <string.h>
17 #include <time.h>
18 #include <sys/stat.h>
19 #include <errno.h>
20 #include <iostream>
21 #include "mbr.h"
22
23 using namespace std;
24
25 /****************************************
26 * *
27 * MBRData class and related structures *
28 * *
29 ****************************************/
30
31 /* // Assignment operator -- copy entire set of MBR data.
32 MBRData & MBRData::operator=(const MBRData & orig) {
33 BasicMBRData::operator=(orig);
34 return *this;
35 } // MBRData::operator=() */
36
37 // Assignment operator -- copy entire set of MBR data.
operator =(const BasicMBRData & orig)38 MBRData & MBRData::operator=(const BasicMBRData & orig) {
39 BasicMBRData::operator=(orig);
40 return *this;
41 } // MBRData::operator=()
42
43 /*****************************************************
44 * *
45 * Functions to create, delete, or change partitions *
46 * *
47 *****************************************************/
48
49 // Create a protective MBR. Clears the boot loader area if clearBoot > 0.
MakeProtectiveMBR(int clearBoot)50 void MBRData::MakeProtectiveMBR(int clearBoot) {
51
52 EmptyMBR(clearBoot);
53
54 // Initialize variables
55 nulls = 0;
56 MBRSignature = MBR_SIGNATURE;
57 diskSignature = UINT32_C(0);
58
59 partitions[0].SetStatus(0); // Flag the protective part. as unbootable
60
61 partitions[0].SetType(UINT8_C(0xEE));
62 if (diskSize < UINT32_MAX) { // If the disk is under 2TiB
63 partitions[0].SetLocation(UINT32_C(1), (uint32_t) diskSize - UINT32_C(1));
64 } else { // disk is too big to represent, so fake it...
65 partitions[0].SetLocation(UINT32_C(1), UINT32_MAX);
66 } // if/else
67 partitions[0].SetInclusion(PRIMARY);
68
69 state = gpt;
70 } // MBRData::MakeProtectiveMBR()
71
72 // Optimizes the size of the 0xEE (EFI GPT) partition
OptimizeEESize(void)73 void MBRData::OptimizeEESize(void) {
74 int i, typeFlag = 0;
75 uint64_t after;
76
77 for (i = 0; i < 4; i++) {
78 // Check for non-empty and non-0xEE partitions
79 if ((partitions[i].GetType() != 0xEE) && (partitions[i].GetType() != 0x00))
80 typeFlag++;
81 if (partitions[i].GetType() == 0xEE) {
82 // Blank space before this partition; fill it....
83 if (SectorUsedAs(partitions[i].GetStartLBA() - 1, 4) == NONE) {
84 partitions[i].SetStartLBA(FindFirstInFree(partitions[i].GetStartLBA() - 1));
85 } // if
86 // Blank space after this partition; fill it....
87 after = partitions[i].GetStartLBA() + partitions[i].GetLengthLBA();
88 if (SectorUsedAs(after, 4) == NONE) {
89 partitions[i].SetLengthLBA(FindLastInFree(after) - partitions[i].GetStartLBA() + 1);
90 } // if free space after
91 if (after > diskSize) {
92 if (diskSize < UINT32_MAX) { // If the disk is under 2TiB
93 partitions[i].SetLengthLBA((uint32_t) diskSize - partitions[i].GetStartLBA());
94 } else { // disk is too big to represent, so fake it...
95 partitions[i].SetLengthLBA(UINT32_MAX - partitions[i].GetStartLBA());
96 } // if/else
97 } // if protective partition is too big
98 RecomputeCHS(i);
99 } // if partition is 0xEE
100 } // for partition loop
101 if (typeFlag == 0) { // No non-hybrid partitions found
102 MakeProtectiveMBR(); // ensure it's a fully compliant protective MBR.
103 } // if
104 } // MBRData::OptimizeEESize()
105
106 // Delete a partition if one exists at the specified location.
107 // Returns 1 if a partition was deleted, 0 otherwise....
108 // Used to help keep GPT & hybrid MBR partitions in sync....
DeleteByLocation(uint64_t start64,uint64_t length64)109 int MBRData::DeleteByLocation(uint64_t start64, uint64_t length64) {
110 uint32_t start32, length32;
111 int i, deleted = 0;
112
113 if ((start64 < UINT32_MAX) && (length64 < UINT32_MAX)) {
114 start32 = (uint32_t) start64;
115 length32 = (uint32_t) length64;
116 for (i = 0; i < MAX_MBR_PARTS; i++) {
117 if ((partitions[i].GetType() != 0xEE) && (partitions[i].GetStartLBA() == start32)
118 && (partitions[i].GetLengthLBA() == length32)) {
119 DeletePartition(i);
120 if (state == hybrid)
121 OptimizeEESize();
122 deleted = 1;
123 } // if (match found)
124 } // for i (partition scan)
125 } // if (hybrid & GPT partition < 2TiB)
126 return deleted;
127 } // MBRData::DeleteByLocation()
128
129 /******************************************************
130 * *
131 * Functions that extract data on specific partitions *
132 * *
133 ******************************************************/
134
135 // Return the MBR data as a GPT partition....
AsGPT(int i)136 GPTPart MBRData::AsGPT(int i) {
137 MBRPart* origPart;
138 GPTPart newPart;
139 uint8_t origType;
140 uint64_t firstSector, lastSector;
141
142 newPart.BlankPartition();
143 origPart = GetPartition(i);
144 if (origPart != NULL) {
145 origType = origPart->GetType();
146
147 // don't convert extended, hybrid protective, or null (non-existent)
148 // partitions (Note similar protection is in GPTData::XFormPartitions(),
149 // but I want it here too in case I call this function in another
150 // context in the future....)
151 if ((origType != 0x05) && (origType != 0x0f) && (origType != 0x85) &&
152 (origType != 0x00) && (origType != 0xEE)) {
153 firstSector = (uint64_t) origPart->GetStartLBA();
154 newPart.SetFirstLBA(firstSector);
155 lastSector = (uint64_t) origPart->GetLastLBA();
156 newPart.SetLastLBA(lastSector);
157 newPart.SetType(((uint16_t) origType) * 0x0100);
158 newPart.RandomizeUniqueGUID();
159 newPart.SetAttributes(0);
160 newPart.SetName(newPart.GetTypeName());
161 } // if not extended, protective, or non-existent
162 } // if (origPart != NULL)
163 return newPart;
164 } // MBRData::AsGPT()
165
166