1 //
2 // C++ Interface: diskio (Windows-specific components)
3 //
4 // Description: Class to handle low-level disk I/O for GPT fdisk
5 //
6 //
7 // Author: Rod Smith <rodsmith@rodsbooks.com>, (C) 2009
8 //
9 // Copyright: See COPYING file that comes with this distribution
10 //
11 //
12 // This program is copyright (c) 2009, 2010 by Roderick W. Smith. It is distributed
13 // under the terms of the GNU GPL version 2, as detailed in the COPYING file.
14
15 #define __STDC_LIMIT_MACROS
16 #define __STDC_CONSTANT_MACROS
17
18 #include <windows.h>
19 #include <winioctl.h>
20 #define fstat64 fstat
21 #define stat64 stat
22 #define S_IRGRP 0
23 #define S_IROTH 0
24 #include <stdio.h>
25 #include <string>
26 #include <stdint.h>
27 #include <errno.h>
28 #include <fcntl.h>
29 #include <sys/stat.h>
30 #include <iostream>
31
32 #include "support.h"
33 #include "diskio.h"
34
35 using namespace std;
36
37 // Returns the official Windows name for a shortened version of same.
MakeRealName(void)38 void DiskIO::MakeRealName(void) {
39 size_t colonPos;
40
41 colonPos = userFilename.find(':', 0);
42 if ((colonPos != string::npos) && (colonPos <= 3)) {
43 realFilename = "\\\\.\\physicaldrive";
44 realFilename += userFilename.substr(0, colonPos);
45 } else {
46 realFilename = userFilename;
47 } // if/else
48 } // DiskIO::MakeRealName()
49
50 // Open the currently on-record file for reading
OpenForRead(void)51 int DiskIO::OpenForRead(void) {
52 int shouldOpen = 1;
53
54 if (isOpen) { // file is already open
55 if (openForWrite) {
56 Close();
57 } else {
58 shouldOpen = 0;
59 } // if/else
60 } // if
61
62 if (shouldOpen) {
63 fd = CreateFile(realFilename.c_str(),GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE,
64 NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
65 if (fd == INVALID_HANDLE_VALUE) {
66 CloseHandle(fd);
67 cerr << "Problem opening " << realFilename << " for reading!\n";
68 realFilename = "";
69 userFilename = "";
70 isOpen = 0;
71 openForWrite = 0;
72 } else {
73 isOpen = 1;
74 openForWrite = 0;
75 } // if/else
76 } // if
77
78 return isOpen;
79 } // DiskIO::OpenForRead(void)
80
81 // An extended file-open function. This includes some system-specific checks.
82 // Returns 1 if the file is open, 0 otherwise....
OpenForWrite(void)83 int DiskIO::OpenForWrite(void) {
84 if ((isOpen) && (openForWrite))
85 return 1;
86
87 // Close the disk, in case it's already open for reading only....
88 Close();
89
90 // try to open the device; may fail....
91 fd = CreateFile(realFilename.c_str(), GENERIC_READ | GENERIC_WRITE,
92 FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING,
93 FILE_ATTRIBUTE_NORMAL, NULL);
94 // Preceding call can fail when creating backup files; if so, try
95 // again with different option...
96 if (fd == INVALID_HANDLE_VALUE) {
97 CloseHandle(fd);
98 fd = CreateFile(realFilename.c_str(), GENERIC_READ | GENERIC_WRITE,
99 FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_ALWAYS,
100 FILE_ATTRIBUTE_NORMAL, NULL);
101 } // if
102 if (fd == INVALID_HANDLE_VALUE) {
103 CloseHandle(fd);
104 isOpen = 0;
105 openForWrite = 0;
106 errno = GetLastError();
107 } else {
108 isOpen = 1;
109 openForWrite = 1;
110 } // if/else
111 return isOpen;
112 } // DiskIO::OpenForWrite(void)
113
114 // Close the disk device. Note that this does NOT erase the stored filenames,
115 // so the file can be re-opened without specifying the filename.
Close(void)116 void DiskIO::Close(void) {
117 if (isOpen)
118 CloseHandle(fd);
119 isOpen = 0;
120 openForWrite = 0;
121 } // DiskIO::Close()
122
123 // Returns block size of device pointed to by fd file descriptor. If the ioctl
124 // returns an error condition, assume it's a disk file and return a value of
125 // SECTOR_SIZE (512). If the disk can't be opened at all, return a value of 0.
GetBlockSize(void)126 int DiskIO::GetBlockSize(void) {
127 DWORD blockSize = 0, retBytes;
128 DISK_GEOMETRY_EX geom;
129
130 // If disk isn't open, try to open it....
131 if (!isOpen) {
132 OpenForRead();
133 } // if
134
135 if (isOpen) {
136 if (DeviceIoControl(fd, IOCTL_DISK_GET_DRIVE_GEOMETRY_EX, NULL, 0,
137 &geom, sizeof(geom), &retBytes, NULL)) {
138 blockSize = geom.Geometry.BytesPerSector;
139 } else { // was probably an ordinary file; set default value....
140 blockSize = SECTOR_SIZE;
141 } // if/else
142 } // if (isOpen)
143
144 return (blockSize);
145 } // DiskIO::GetBlockSize()
146
147 // Returns the number of heads, according to the kernel, or 255 if the
148 // correct value can't be determined.
GetNumHeads(void)149 uint32_t DiskIO::GetNumHeads(void) {
150 return UINT32_C(255);
151 } // DiskIO::GetNumHeads();
152
153 // Returns the number of sectors per track, according to the kernel, or 63
154 // if the correct value can't be determined.
GetNumSecsPerTrack(void)155 uint32_t DiskIO::GetNumSecsPerTrack(void) {
156 return UINT32_C(63);
157 } // DiskIO::GetNumSecsPerTrack()
158
159 // Resync disk caches so the OS uses the new partition table. This code varies
160 // a lot from one OS to another.
161 // Returns 1 on success, 0 if the kernel continues to use the old partition table.
DiskSync(void)162 int DiskIO::DiskSync(void) {
163 DWORD i;
164 GET_LENGTH_INFORMATION buf;
165 int retval = 0;
166
167 // If disk isn't open, try to open it....
168 if (!openForWrite) {
169 OpenForWrite();
170 } // if
171
172 if (isOpen) {
173 if (DeviceIoControl(fd, IOCTL_DISK_UPDATE_PROPERTIES, NULL, 0, &buf, sizeof(buf), &i, NULL) == 0) {
174 cout << "Disk synchronization failed! The computer may use the old partition table\n"
175 << "until you reboot or remove and re-insert the disk!\n";
176 } else {
177 cout << "Disk synchronization succeeded! The computer should now use the new\n"
178 << "partition table.\n";
179 retval = 1;
180 } // if/else
181 } else {
182 cout << "Unable to open the disk for synchronization operation! The computer will\n"
183 << "continue to use the old partition table until you reboot or remove and\n"
184 << "re-insert the disk!\n";
185 } // if (isOpen)
186 return retval;
187 } // DiskIO::DiskSync()
188
189 // Seek to the specified sector. Returns 1 on success, 0 on failure.
Seek(uint64_t sector)190 int DiskIO::Seek(uint64_t sector) {
191 int retval = 1;
192 LARGE_INTEGER seekTo;
193
194 // If disk isn't open, try to open it....
195 if (!isOpen) {
196 retval = OpenForRead();
197 } // if
198
199 if (isOpen) {
200 seekTo.QuadPart = sector * (uint64_t) GetBlockSize();
201 retval = SetFilePointerEx(fd, seekTo, NULL, FILE_BEGIN);
202 if (retval == 0) {
203 errno = GetLastError();
204 cerr << "Error when seeking to " << seekTo.QuadPart << "! Error is " << errno << "\n";
205 retval = 0;
206 } // if
207 } // if
208 return retval;
209 } // DiskIO::Seek()
210
211 // A variant on the standard read() function. Done to work around
212 // limitations in FreeBSD concerning the matching of the sector
213 // size with the number of bytes read.
214 // Returns the number of bytes read into buffer.
Read(void * buffer,int numBytes)215 int DiskIO::Read(void* buffer, int numBytes) {
216 int blockSize = 512, i, numBlocks;
217 char* tempSpace;
218 DWORD retval = 0;
219
220 // If disk isn't open, try to open it....
221 if (!isOpen) {
222 OpenForRead();
223 } // if
224
225 if (isOpen) {
226 // Compute required space and allocate memory
227 blockSize = GetBlockSize();
228 if (numBytes <= blockSize) {
229 numBlocks = 1;
230 tempSpace = new char [blockSize];
231 } else {
232 numBlocks = numBytes / blockSize;
233 if ((numBytes % blockSize) != 0)
234 numBlocks++;
235 tempSpace = new char [numBlocks * blockSize];
236 } // if/else
237 if (tempSpace == NULL) {
238 cerr << "Unable to allocate memory in DiskIO::Read()! Terminating!\n";
239 exit(1);
240 } // if
241
242 // Read the data into temporary space, then copy it to buffer
243 ReadFile(fd, tempSpace, numBlocks * blockSize, &retval, NULL);
244 for (i = 0; i < numBytes; i++) {
245 ((char*) buffer)[i] = tempSpace[i];
246 } // for
247
248 // Adjust the return value, if necessary....
249 if (((numBlocks * blockSize) != numBytes) && (retval > 0))
250 retval = numBytes;
251
252 delete[] tempSpace;
253 } // if (isOpen)
254 return retval;
255 } // DiskIO::Read()
256
257 // A variant on the standard write() function.
258 // Returns the number of bytes written.
Write(void * buffer,int numBytes)259 int DiskIO::Write(void* buffer, int numBytes) {
260 int blockSize = 512, i, numBlocks, retval = 0;
261 char* tempSpace;
262 DWORD numWritten;
263
264 // If disk isn't open, try to open it....
265 if ((!isOpen) || (!openForWrite)) {
266 OpenForWrite();
267 } // if
268
269 if (isOpen) {
270 // Compute required space and allocate memory
271 blockSize = GetBlockSize();
272 if (numBytes <= blockSize) {
273 numBlocks = 1;
274 tempSpace = new char [blockSize];
275 } else {
276 numBlocks = numBytes / blockSize;
277 if ((numBytes % blockSize) != 0) numBlocks++;
278 tempSpace = new char [numBlocks * blockSize];
279 } // if/else
280 if (tempSpace == NULL) {
281 cerr << "Unable to allocate memory in DiskIO::Write()! Terminating!\n";
282 exit(1);
283 } // if
284
285 // Copy the data to my own buffer, then write it
286 for (i = 0; i < numBytes; i++) {
287 tempSpace[i] = ((char*) buffer)[i];
288 } // for
289 for (i = numBytes; i < numBlocks * blockSize; i++) {
290 tempSpace[i] = 0;
291 } // for
292 WriteFile(fd, tempSpace, numBlocks * blockSize, &numWritten, NULL);
293 retval = (int) numWritten;
294
295 // Adjust the return value, if necessary....
296 if (((numBlocks * blockSize) != numBytes) && (retval > 0))
297 retval = numBytes;
298
299 delete[] tempSpace;
300 } // if (isOpen)
301 return retval;
302 } // DiskIO:Write()
303
304 // Returns the size of the disk in blocks.
DiskSize(int * err)305 uint64_t DiskIO::DiskSize(int *err) {
306 uint64_t sectors = 0; // size in sectors
307 DWORD bytes, moreBytes; // low- and high-order bytes of file size
308 GET_LENGTH_INFORMATION buf;
309 DWORD i;
310
311 // If disk isn't open, try to open it....
312 if (!isOpen) {
313 OpenForRead();
314 } // if
315
316 if (isOpen) {
317 // Note to self: I recall testing a simplified version of
318 // this code, similar to what's in the __APPLE__ block,
319 // on Linux, but I had some problems. IIRC, it ran OK on 32-bit
320 // systems but not on 64-bit. Keep this in mind in case of
321 // 32/64-bit issues on MacOS....
322 if (DeviceIoControl(fd, IOCTL_DISK_GET_LENGTH_INFO, NULL, 0, &buf, sizeof(buf), &i, NULL)) {
323 sectors = (uint64_t) buf.Length.QuadPart / GetBlockSize();
324 *err = 0;
325 } else { // doesn't seem to be a disk device; assume it's an image file....
326 bytes = GetFileSize(fd, &moreBytes);
327 sectors = ((uint64_t) bytes + ((uint64_t) moreBytes) * UINT32_MAX) / GetBlockSize();
328 *err = 0;
329 } // if
330 } else {
331 *err = -1;
332 sectors = 0;
333 } // if/else (isOpen)
334
335 return sectors;
336 } // DiskIO::DiskSize()
337