cf790d45e3a6654b82112fcbafc7292e1be9846b
[mirror_edk2.git] / EdkModulePkg / Universal / Disk / Partition / Dxe / Mbr.c
1 /*++
2
3 Copyright (c) 2006 - 2007, Intel Corporation
4 All rights reserved. This program and the accompanying materials
5 are licensed and made available under the terms and conditions of the BSD License
6 which accompanies this distribution. The full text of the license may be found at
7 http://opensource.org/licenses/bsd-license.php
8
9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
11
12 Module Name:
13
14 Mbr.c
15
16 Abstract:
17
18 Decode a hard disk partitioned with the legacy MBR found on most PC's
19
20 MBR - Master Boot Record is in the first sector of a partitioned hard disk.
21 The MBR supports four partitions per disk. The MBR also contains legacy
22 code that is not run on an EFI system. The legacy code reads the
23 first sector of the active partition into memory and
24
25 BPB - Boot(?) Parameter Block is in the first sector of a FAT file system.
26 The BPB contains information about the FAT file system. The BPB is
27 always on the first sector of a media. The first sector also contains
28 the legacy boot strap code.
29
30 --*/
31
32 #include "Partition.h"
33
34 STATIC
35 BOOLEAN
36 PartitionValidMbr (
37 IN MASTER_BOOT_RECORD *Mbr,
38 IN EFI_LBA LastLba
39 )
40 /*++
41
42 Routine Description:
43 Test to see if the Mbr buffer is a valid MBR
44
45 Arguments:
46 Mbr - Parent Handle
47 LastLba - Last Lba address on the device.
48
49 Returns:
50 TRUE - Mbr is a Valid MBR
51 FALSE - Mbr is not a Valid MBR
52
53 --*/
54 {
55 UINT32 StartingLBA;
56 UINT32 EndingLBA;
57 UINT32 NewEndingLBA;
58 INTN Index1;
59 INTN Index2;
60 BOOLEAN MbrValid;
61
62 if (Mbr->Signature != MBR_SIGNATURE) {
63 return FALSE;
64 }
65 //
66 // The BPB also has this signature, so it can not be used alone.
67 //
68 MbrValid = FALSE;
69 for (Index1 = 0; Index1 < MAX_MBR_PARTITIONS; Index1++) {
70 if (Mbr->Partition[Index1].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA) == 0) {
71 continue;
72 }
73
74 MbrValid = TRUE;
75 StartingLBA = UNPACK_UINT32 (Mbr->Partition[Index1].StartingLBA);
76 EndingLBA = StartingLBA + UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA) - 1;
77 if (EndingLBA > LastLba) {
78 //
79 // Compatibility Errata:
80 // Some systems try to hide drive space with their INT 13h driver
81 // This does not hide space from the OS driver. This means the MBR
82 // that gets created from DOS is smaller than the MBR created from
83 // a real OS (NT & Win98). This leads to BlockIo->LastBlock being
84 // wrong on some systems FDISKed by the OS.
85 //
86 // return FALSE since no block devices on a system are implemented
87 // with INT 13h
88 //
89 return FALSE;
90 }
91
92 for (Index2 = Index1 + 1; Index2 < MAX_MBR_PARTITIONS; Index2++) {
93 if (Mbr->Partition[Index2].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index2].SizeInLBA) == 0) {
94 continue;
95 }
96
97 NewEndingLBA = UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA) + UNPACK_UINT32 (Mbr->Partition[Index2].SizeInLBA) - 1;
98 if (NewEndingLBA >= StartingLBA && UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA) <= EndingLBA) {
99 //
100 // This region overlaps with the Index1'th region
101 //
102 return FALSE;
103 }
104 }
105 }
106 //
107 // Non of the regions overlapped so MBR is O.K.
108 //
109 return MbrValid;
110 }
111
112 EFI_STATUS
113 PartitionInstallMbrChildHandles (
114 IN EFI_DRIVER_BINDING_PROTOCOL *This,
115 IN EFI_HANDLE Handle,
116 IN EFI_DISK_IO_PROTOCOL *DiskIo,
117 IN EFI_BLOCK_IO_PROTOCOL *BlockIo,
118 IN EFI_DEVICE_PATH_PROTOCOL *DevicePath
119 )
120 /*++
121
122 Routine Description:
123 Install child handles if the Handle supports MBR format.
124
125 Arguments:
126 This - Calling context.
127 Handle - Parent Handle
128 DiskIo - Parent DiskIo interface
129 BlockIo - Parent BlockIo interface
130 DevicePath - Parent Device Path
131
132 Returns:
133 EFI_SUCCESS - If a child handle was added
134 EFI_MEDIA_CHANGED - Media changed Detected
135 !EFI_SUCCESS - Not found MBR partition.
136
137 --*/
138 {
139 EFI_STATUS Status;
140 MASTER_BOOT_RECORD *Mbr;
141 UINT32 ExtMbrStartingLba;
142 UINTN Index;
143 HARDDRIVE_DEVICE_PATH HdDev;
144 HARDDRIVE_DEVICE_PATH ParentHdDev;
145 EFI_STATUS Found;
146 UINT32 PartitionNumber;
147 EFI_DEVICE_PATH_PROTOCOL *DevicePathNode;
148 EFI_DEVICE_PATH_PROTOCOL *LastDevicePathNode;
149
150 Mbr = NULL;
151 Found = EFI_NOT_FOUND;
152
153 Mbr = AllocatePool (BlockIo->Media->BlockSize);
154 if (Mbr == NULL) {
155 goto Done;
156 }
157
158 Status = BlockIo->ReadBlocks (
159 BlockIo,
160 BlockIo->Media->MediaId,
161 0,
162 BlockIo->Media->BlockSize,
163 Mbr
164 );
165 if (EFI_ERROR (Status) || !PartitionValidMbr (Mbr, BlockIo->Media->LastBlock)) {
166 Found = Status;
167 goto Done;
168 }
169 //
170 // We have a valid mbr - add each partition
171 //
172 //
173 // Get starting and ending LBA of the parent block device.
174 //
175 LastDevicePathNode = NULL;
176 ZeroMem (&ParentHdDev, sizeof (ParentHdDev));
177 DevicePathNode = DevicePath;
178 while (!EfiIsDevicePathEnd (DevicePathNode)) {
179 LastDevicePathNode = DevicePathNode;
180 DevicePathNode = EfiNextDevicePathNode (DevicePathNode);
181 }
182
183 if (LastDevicePathNode != NULL) {
184 if (DevicePathType (LastDevicePathNode) == MEDIA_DEVICE_PATH &&
185 DevicePathSubType (LastDevicePathNode) == MEDIA_HARDDRIVE_DP
186 ) {
187 CopyMem (&ParentHdDev, LastDevicePathNode, sizeof (ParentHdDev));
188 } else {
189 LastDevicePathNode = NULL;
190 }
191 }
192
193 PartitionNumber = 1;
194
195 ZeroMem (&HdDev, sizeof (HdDev));
196 HdDev.Header.Type = MEDIA_DEVICE_PATH;
197 HdDev.Header.SubType = MEDIA_HARDDRIVE_DP;
198 SetDevicePathNodeLength (&HdDev.Header, sizeof (HdDev));
199 HdDev.MBRType = MBR_TYPE_PCAT;
200 HdDev.SignatureType = SIGNATURE_TYPE_MBR;
201
202 if (LastDevicePathNode == NULL) {
203 //
204 // This is a MBR, add each partition
205 //
206 for (Index = 0; Index < MAX_MBR_PARTITIONS; Index++) {
207 if (Mbr->Partition[Index].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index].SizeInLBA) == 0) {
208 //
209 // Don't use null MBR entries
210 //
211 continue;
212 }
213
214 if (Mbr->Partition[Index].OSIndicator == PMBR_GPT_PARTITION) {
215 //
216 // This is the guard MBR for the GPT. If you ever see a GPT disk with zero partitions you can get here.
217 // We can not produce an MBR BlockIo for this device as the MBR spans the GPT headers. So formating
218 // this BlockIo would corrupt the GPT structures and require a recovery that would corrupt the format
219 // that corrupted the GPT partition.
220 //
221 continue;
222 }
223
224 HdDev.PartitionNumber = PartitionNumber ++;
225 HdDev.PartitionStart = UNPACK_UINT32 (Mbr->Partition[Index].StartingLBA);
226 HdDev.PartitionSize = UNPACK_UINT32 (Mbr->Partition[Index].SizeInLBA);
227 CopyMem (HdDev.Signature, &(Mbr->UniqueMbrSignature[0]), sizeof (UINT32));
228
229 Status = PartitionInstallChildHandle (
230 This,
231 Handle,
232 DiskIo,
233 BlockIo,
234 DevicePath,
235 (EFI_DEVICE_PATH_PROTOCOL *) &HdDev,
236 HdDev.PartitionStart,
237 HdDev.PartitionStart + HdDev.PartitionSize - 1,
238 MBR_SIZE,
239 (BOOLEAN) (Mbr->Partition[Index].OSIndicator == EFI_PARTITION)
240 );
241
242 if (!EFI_ERROR (Status)) {
243 Found = EFI_SUCCESS;
244 }
245 }
246 } else {
247 //
248 // It's an extended partition. Follow the extended partition
249 // chain to get all the logical drives
250 //
251 ExtMbrStartingLba = 0;
252
253 do {
254
255 Status = BlockIo->ReadBlocks (
256 BlockIo,
257 BlockIo->Media->MediaId,
258 ExtMbrStartingLba,
259 BlockIo->Media->BlockSize,
260 Mbr
261 );
262 if (EFI_ERROR (Status)) {
263 Found = Status;
264 goto Done;
265 }
266
267 if (Mbr->Partition[0].OSIndicator == 0) {
268 break;
269 }
270
271 if ((Mbr->Partition[0].OSIndicator == EXTENDED_DOS_PARTITION) ||
272 (Mbr->Partition[0].OSIndicator == EXTENDED_WINDOWS_PARTITION)) {
273 ExtMbrStartingLba = UNPACK_UINT32 (Mbr->Partition[0].StartingLBA);
274 continue;
275 }
276 HdDev.PartitionNumber = PartitionNumber ++;
277 HdDev.PartitionStart = UNPACK_UINT32 (Mbr->Partition[0].StartingLBA) + ExtMbrStartingLba + ParentHdDev.PartitionStart;
278 HdDev.PartitionSize = UNPACK_UINT32 (Mbr->Partition[0].SizeInLBA);
279 if ((HdDev.PartitionStart + HdDev.PartitionSize - 1 >= ParentHdDev.PartitionStart + ParentHdDev.PartitionSize) ||
280 (HdDev.PartitionStart <= ParentHdDev.PartitionStart)) {
281 break;
282 }
283
284 //
285 // The signature in EBR(Extended Boot Record) should always be 0.
286 //
287 *((UINT32 *) &HdDev.Signature[0]) = 0;
288
289 Status = PartitionInstallChildHandle (
290 This,
291 Handle,
292 DiskIo,
293 BlockIo,
294 DevicePath,
295 (EFI_DEVICE_PATH_PROTOCOL *) &HdDev,
296 HdDev.PartitionStart - ParentHdDev.PartitionStart,
297 HdDev.PartitionStart - ParentHdDev.PartitionStart + HdDev.PartitionSize - 1,
298 MBR_SIZE,
299 (BOOLEAN) (Mbr->Partition[0].OSIndicator == EFI_PARTITION)
300 );
301 if (!EFI_ERROR (Status)) {
302 Found = EFI_SUCCESS;
303 }
304
305 if ((Mbr->Partition[1].OSIndicator != EXTENDED_DOS_PARTITION) &&
306 (Mbr->Partition[1].OSIndicator != EXTENDED_WINDOWS_PARTITION)
307 ) {
308 break;
309 }
310
311 ExtMbrStartingLba = UNPACK_UINT32 (Mbr->Partition[1].StartingLBA);
312 //
313 // Don't allow partition to be self referencing
314 //
315 if (ExtMbrStartingLba == 0) {
316 break;
317 }
318 } while (ExtMbrStartingLba < ParentHdDev.PartitionSize);
319 }
320
321 Done:
322 FreePool (Mbr);
323
324 return Found;
325 }