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1/** @file\r
2 Decode a hard disk partitioned with the legacy MBR found on most PC's\r
3\r
4 MBR - Master Boot Record is in the first sector of a partitioned hard disk.\r
5 The MBR supports four partitions per disk. The MBR also contains legacy\r
6 code that is not run on an EFI system. The legacy code reads the \r
7 first sector of the active partition into memory and \r
8\r
9 BPB - BIOS Parameter Block is in the first sector of a FAT file system. \r
10 The BPB contains information about the FAT file system. The BPB is \r
11 always on the first sector of a media. The first sector also contains\r
12 the legacy boot strap code.\r
13\r
14Copyright (c) 2014, Hewlett-Packard Development Company, L.P.<BR>\r
15Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>\r
16This program and the accompanying materials\r
17are licensed and made available under the terms and conditions of the BSD License\r
18which accompanies this distribution. The full text of the license may be found at\r
19http://opensource.org/licenses/bsd-license.php\r
20\r
21THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
22WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
23\r
24**/\r
25\r
26#include "Partition.h"\r
27\r
28/**\r
29 Test to see if the Mbr buffer is a valid MBR.\r
30\r
31 @param Mbr Parent Handle.\r
32 @param LastLba Last Lba address on the device.\r
33 \r
34 @retval TRUE Mbr is a Valid MBR.\r
35 @retval FALSE Mbr is not a Valid MBR.\r
36\r
37**/\r
38BOOLEAN\r
39PartitionValidMbr (\r
40 IN MASTER_BOOT_RECORD *Mbr,\r
41 IN EFI_LBA LastLba\r
42 )\r
43{\r
44 UINT32 StartingLBA;\r
45 UINT32 EndingLBA;\r
46 UINT32 NewEndingLBA;\r
47 INTN Index1;\r
48 INTN Index2;\r
49 BOOLEAN MbrValid;\r
50\r
51 if (Mbr->Signature != MBR_SIGNATURE) {\r
52 return FALSE;\r
53 }\r
54 //\r
55 // The BPB also has this signature, so it can not be used alone.\r
56 //\r
57 MbrValid = FALSE;\r
58 for (Index1 = 0; Index1 < MAX_MBR_PARTITIONS; Index1++) {\r
59 if (Mbr->Partition[Index1].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA) == 0) {\r
60 continue;\r
61 }\r
62\r
63 MbrValid = TRUE;\r
64 StartingLBA = UNPACK_UINT32 (Mbr->Partition[Index1].StartingLBA);\r
65 EndingLBA = StartingLBA + UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA) - 1;\r
66 if (EndingLBA > LastLba) {\r
67 //\r
68 // Compatibility Errata:\r
69 // Some systems try to hide drive space with their INT 13h driver\r
70 // This does not hide space from the OS driver. This means the MBR\r
71 // that gets created from DOS is smaller than the MBR created from\r
72 // a real OS (NT & Win98). This leads to BlockIo->LastBlock being\r
73 // wrong on some systems FDISKed by the OS.\r
74 //\r
75 // return FALSE since no block devices on a system are implemented\r
76 // with INT 13h\r
77 //\r
78 \r
79 DEBUG((EFI_D_INFO, "PartitionValidMbr: Bad MBR partition size EndingLBA(%1x) > LastLBA(%1x)\n", EndingLBA, LastLba));\r
80\r
81 return FALSE;\r
82 }\r
83\r
84 for (Index2 = Index1 + 1; Index2 < MAX_MBR_PARTITIONS; Index2++) {\r
85 if (Mbr->Partition[Index2].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index2].SizeInLBA) == 0) {\r
86 continue;\r
87 }\r
88\r
89 NewEndingLBA = UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA) + UNPACK_UINT32 (Mbr->Partition[Index2].SizeInLBA) - 1;\r
90 if (NewEndingLBA >= StartingLBA && UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA) <= EndingLBA) {\r
91 //\r
92 // This region overlaps with the Index1'th region\r
93 //\r
94 return FALSE;\r
95 }\r
96 }\r
97 }\r
98 //\r
99 // None of the regions overlapped so MBR is O.K.\r
100 //\r
101 return MbrValid;\r
102}\r
103\r
104\r
105/**\r
106 Install child handles if the Handle supports MBR format.\r
107\r
108 @param[in] This Calling context.\r
109 @param[in] Handle Parent Handle.\r
110 @param[in] DiskIo Parent DiskIo interface.\r
111 @param[in] DiskIo2 Parent DiskIo2 interface.\r
112 @param[in] BlockIo Parent BlockIo interface.\r
113 @param[in] BlockIo2 Parent BlockIo2 interface.\r
114 @param[in] DevicePath Parent Device Path.\r
115 \r
116 @retval EFI_SUCCESS A child handle was added.\r
117 @retval EFI_MEDIA_CHANGED Media change was detected.\r
118 @retval Others MBR partition was not found.\r
119\r
120**/\r
121EFI_STATUS\r
122PartitionInstallMbrChildHandles (\r
123 IN EFI_DRIVER_BINDING_PROTOCOL *This,\r
124 IN EFI_HANDLE Handle,\r
125 IN EFI_DISK_IO_PROTOCOL *DiskIo,\r
126 IN EFI_DISK_IO2_PROTOCOL *DiskIo2,\r
127 IN EFI_BLOCK_IO_PROTOCOL *BlockIo,\r
128 IN EFI_BLOCK_IO2_PROTOCOL *BlockIo2,\r
129 IN EFI_DEVICE_PATH_PROTOCOL *DevicePath\r
130 )\r
131{\r
132 EFI_STATUS Status;\r
133 MASTER_BOOT_RECORD *Mbr;\r
134 UINT32 ExtMbrStartingLba;\r
135 UINTN Index;\r
136 HARDDRIVE_DEVICE_PATH HdDev;\r
137 HARDDRIVE_DEVICE_PATH ParentHdDev;\r
138 EFI_STATUS Found;\r
139 UINT32 PartitionNumber;\r
140 EFI_DEVICE_PATH_PROTOCOL *DevicePathNode;\r
141 EFI_DEVICE_PATH_PROTOCOL *LastDevicePathNode;\r
142 UINT32 BlockSize;\r
143 UINT32 MediaId;\r
144 EFI_LBA LastBlock;\r
145\r
146 Found = EFI_NOT_FOUND;\r
147\r
148 BlockSize = BlockIo->Media->BlockSize;\r
149 MediaId = BlockIo->Media->MediaId;\r
150 LastBlock = BlockIo->Media->LastBlock;\r
151\r
152 Mbr = AllocatePool (BlockSize);\r
153 if (Mbr == NULL) {\r
154 return Found;\r
155 }\r
156\r
157 Status = DiskIo->ReadDisk (\r
158 DiskIo,\r
159 MediaId,\r
160 0,\r
161 BlockSize,\r
162 Mbr\r
163 );\r
164 if (EFI_ERROR (Status)) {\r
165 Found = Status;\r
166 goto Done;\r
167 }\r
168 if (!PartitionValidMbr (Mbr, LastBlock)) {\r
169 goto Done;\r
170 }\r
171 //\r
172 // We have a valid mbr - add each partition\r
173 //\r
174 //\r
175 // Get starting and ending LBA of the parent block device.\r
176 //\r
177 LastDevicePathNode = NULL;\r
178 ZeroMem (&ParentHdDev, sizeof (ParentHdDev));\r
179 DevicePathNode = DevicePath;\r
180 while (!IsDevicePathEnd (DevicePathNode)) {\r
181 LastDevicePathNode = DevicePathNode;\r
182 DevicePathNode = NextDevicePathNode (DevicePathNode);\r
183 }\r
184\r
185 if (LastDevicePathNode != NULL) {\r
186 if (DevicePathType (LastDevicePathNode) == MEDIA_DEVICE_PATH &&\r
187 DevicePathSubType (LastDevicePathNode) == MEDIA_HARDDRIVE_DP\r
188 ) {\r
189 CopyMem (&ParentHdDev, LastDevicePathNode, sizeof (ParentHdDev));\r
190 } else {\r
191 LastDevicePathNode = NULL;\r
192 }\r
193 }\r
194\r
195 PartitionNumber = 1;\r
196\r
197 ZeroMem (&HdDev, sizeof (HdDev));\r
198 HdDev.Header.Type = MEDIA_DEVICE_PATH;\r
199 HdDev.Header.SubType = MEDIA_HARDDRIVE_DP;\r
200 SetDevicePathNodeLength (&HdDev.Header, sizeof (HdDev));\r
201 HdDev.MBRType = MBR_TYPE_PCAT;\r
202 HdDev.SignatureType = SIGNATURE_TYPE_MBR;\r
203\r
204 if (LastDevicePathNode == NULL) {\r
205 //\r
206 // This is a MBR, add each partition\r
207 //\r
208 for (Index = 0; Index < MAX_MBR_PARTITIONS; Index++) {\r
209 if (Mbr->Partition[Index].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index].SizeInLBA) == 0) {\r
210 //\r
211 // Don't use null MBR entries\r
212 //\r
213 continue;\r
214 }\r
215\r
216 if (Mbr->Partition[Index].OSIndicator == PMBR_GPT_PARTITION) {\r
217 //\r
218 // This is the guard MBR for the GPT. If you ever see a GPT disk with zero partitions you can get here.\r
219 // We can not produce an MBR BlockIo for this device as the MBR spans the GPT headers. So formating \r
220 // this BlockIo would corrupt the GPT structures and require a recovery that would corrupt the format\r
221 // that corrupted the GPT partition. \r
222 //\r
223 continue;\r
224 }\r
225\r
226 HdDev.PartitionNumber = PartitionNumber ++;\r
227 HdDev.PartitionStart = UNPACK_UINT32 (Mbr->Partition[Index].StartingLBA);\r
228 HdDev.PartitionSize = UNPACK_UINT32 (Mbr->Partition[Index].SizeInLBA);\r
229 CopyMem (HdDev.Signature, &(Mbr->UniqueMbrSignature[0]), sizeof (Mbr->UniqueMbrSignature));\r
230\r
231 Status = PartitionInstallChildHandle (\r
232 This,\r
233 Handle,\r
234 DiskIo,\r
235 DiskIo2,\r
236 BlockIo,\r
237 BlockIo2,\r
238 DevicePath,\r
239 (EFI_DEVICE_PATH_PROTOCOL *) &HdDev,\r
240 HdDev.PartitionStart,\r
241 HdDev.PartitionStart + HdDev.PartitionSize - 1,\r
242 MBR_SIZE,\r
243 (BOOLEAN) (Mbr->Partition[Index].OSIndicator == EFI_PARTITION)\r
244 );\r
245\r
246 if (!EFI_ERROR (Status)) {\r
247 Found = EFI_SUCCESS;\r
248 }\r
249 }\r
250 } else {\r
251 //\r
252 // It's an extended partition. Follow the extended partition\r
253 // chain to get all the logical drives\r
254 //\r
255 ExtMbrStartingLba = 0;\r
256\r
257 do {\r
258\r
259 Status = DiskIo->ReadDisk (\r
260 DiskIo,\r
261 MediaId,\r
262 MultU64x32 (ExtMbrStartingLba, BlockSize),\r
263 BlockSize,\r
264 Mbr\r
265 );\r
266 if (EFI_ERROR (Status)) {\r
267 Found = Status;\r
268 goto Done;\r
269 }\r
270\r
271 if (UNPACK_UINT32 (Mbr->Partition[0].SizeInLBA) == 0) {\r
272 break;\r
273 }\r
274\r
275 if ((Mbr->Partition[0].OSIndicator == EXTENDED_DOS_PARTITION) ||\r
276 (Mbr->Partition[0].OSIndicator == EXTENDED_WINDOWS_PARTITION)) {\r
277 ExtMbrStartingLba = UNPACK_UINT32 (Mbr->Partition[0].StartingLBA);\r
278 continue;\r
279 }\r
280 HdDev.PartitionNumber = PartitionNumber ++;\r
281 HdDev.PartitionStart = UNPACK_UINT32 (Mbr->Partition[0].StartingLBA) + ExtMbrStartingLba + ParentHdDev.PartitionStart;\r
282 HdDev.PartitionSize = UNPACK_UINT32 (Mbr->Partition[0].SizeInLBA);\r
283 if ((HdDev.PartitionStart + HdDev.PartitionSize - 1 >= ParentHdDev.PartitionStart + ParentHdDev.PartitionSize) ||\r
284 (HdDev.PartitionStart <= ParentHdDev.PartitionStart)) {\r
285 break;\r
286 }\r
287\r
288 //\r
289 // The signature in EBR(Extended Boot Record) should always be 0.\r
290 //\r
291 *((UINT32 *) &HdDev.Signature[0]) = 0;\r
292\r
293 Status = PartitionInstallChildHandle (\r
294 This,\r
295 Handle,\r
296 DiskIo,\r
297 DiskIo2,\r
298 BlockIo,\r
299 BlockIo2,\r
300 DevicePath,\r
301 (EFI_DEVICE_PATH_PROTOCOL *) &HdDev,\r
302 HdDev.PartitionStart - ParentHdDev.PartitionStart,\r
303 HdDev.PartitionStart - ParentHdDev.PartitionStart + HdDev.PartitionSize - 1,\r
304 MBR_SIZE,\r
305 (BOOLEAN) (Mbr->Partition[0].OSIndicator == EFI_PARTITION)\r
306 );\r
307 if (!EFI_ERROR (Status)) {\r
308 Found = EFI_SUCCESS;\r
309 }\r
310\r
311 if ((Mbr->Partition[1].OSIndicator != EXTENDED_DOS_PARTITION) &&\r
312 (Mbr->Partition[1].OSIndicator != EXTENDED_WINDOWS_PARTITION)\r
313 ) {\r
314 break;\r
315 }\r
316\r
317 ExtMbrStartingLba = UNPACK_UINT32 (Mbr->Partition[1].StartingLBA);\r
318 //\r
319 // Don't allow partition to be self referencing\r
320 //\r
321 if (ExtMbrStartingLba == 0) {\r
322 break;\r
323 }\r
324 } while (ExtMbrStartingLba < ParentHdDev.PartitionSize);\r
325 }\r
326\r
327Done:\r
328 FreePool (Mbr);\r
329\r
330 return Found;\r
331}\r
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