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
35using namespace std;
36
37// Returns the official Windows name for a shortened version of same.
38void 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
51int 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....
83int 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.
116void 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.
126int 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.
149uint32_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.
155uint32_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.
162int 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.
190int 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.
215int 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.
259int 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.
305uint64_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