我正在编写一个在 Windows 上运行的 C#.Net 应用程序,它需要拍摄可移动磁盘的映像并将其放入 Linux Live USB 上。 Live USB 被插入目标机器并启动,启动时它会运行一个脚本,该脚本使用 dd 命令,如下所示将其闪存到另一个驱动器上:
dd if=/path/to/file/from/csharp/program of=/dev/sdX
我遇到的问题是在 Windows 端创建图像。我已经使用 dd 在 Linux 系统上创建的文件尝试了 Live Linux,效果很好,但我需要能够在 Windows 上的 C#.Net 应用程序中创建这些文件。我不想依赖 cygwin 或其他一些依赖项,因此尝试使用 Win32 CreateFile 函数来打开物理设备。
调用 CreateFile 时,第一个参数设置为“\.\F:”(如果 F: 是我想要镜像的驱动器),如下所示:
SafeFileHandle TheDevice = CreateFile(_DevicePath, (uint)FileAccess.Read, (uint)(FileShare.Write | FileShare.Read | FileShare.Delete), IntPtr.Zero, (uint)FileMode.Open, (uint)FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_SEQUENTIAL_SCAN, IntPtr.Zero);
if (TheDevice.IsInvalid)
{
throw new IOException("Unable to access drive. Win32 Error Code " + Marshal.GetLastWin32Error());
}
FileStream Dest = System.IO.File.Open(_SaveFile, FileMode.Create);
FileStream Src = new FileStream(TheDevice, FileAccess.Read);
Src.CopyTo(Dest);
Dest.Flush();
Src.Close();
Dest.Close();
但是当使用 Live Linux USB 将输出文件 dd'd 回磁盘时结果不符合预期(磁盘不可启动等,但通过在十六进制编辑器中检查输出文件,看起来开头有一个 MBR 等)。
这是字节顺序的问题吗?还是我应该使用 FileStream 以外的其他方法将数据复制到文件中。
或者有一个 Windows 源代码的 dd 示例(C# 或 C++,我查看了 Delphi 的 http:// /www.chryscome.net/dd 并且不完全理解它或者没有一个像样的 Delphi IDE 来分离代码)所以我可以看看它是如何工作的?
更新/编辑:
这是 dd 输出包含的前 512 个字节的十六进制字符串:
33 C0 FA 8E D8 8E D0 BC 00 7C 89 E6 06 57 8E C0 FB FC BF 00 06 B9 00 01 F3 A5 EA 1F 06
00 00 52 52 B4 41 BB AA 55 31 C9 30 F6 F9 CD 13 72 13 81 FB 55 AA 75 0D D1 E9 73 09 66
C7 06 8D 06 B4 42 EB 15 5A B4 08 CD 13 83 E1 3F 51 0F B6 C6 40 F7 E1 52 50 66 31 C0 66
99 E8 66 00 E8 21 01 4D 69 73 73 69 6E 67 20 6F 70 65 72 61 74 69 6E 67 20 73 79 73 74
65 6D 2E 0D 0A 66 60 66 31 D2 BB 00 7C 66 52 66 50 06 53 6A 01 6A 10 89 E6 66 F7 36 F4
7B C0 E4 06 88 E1 88 C5 92 F6 36 F8 7B 88 C6 08 E1 41 B8 01 02 8A 16 FA 7B CD 13 8D 64
10 66 61 C3 E8 C4 FF BE BE 7D BF BE 07 B9 20 00 F3 A5 C3 66 60 89 E5 BB BE 07 B9 04 00
31 C0 53 51 F6 07 80 74 03 40 89 DE 83 C3 10 E2 F3 48 74 5B 79 39 59 5B 8A 47 04 3C 0F
74 06 24 7F 3C 05 75 22 66 8B 47 08 66 8B 56 14 66 01 D0 66 21 D2 75 03 66 89 C2 E8 AC
FF 72 03 E8 B6 FF 66 8B 46 1C E8 A0 FF 83 C3 10 E2 CC 66 61 C3 E8 62 00 4D 75 6C 74 69
70 6C 65 20 61 63 74 69 76 65 20 70 61 72 74 69 74 69 6F 6E 73 2E 0D 0A 66 8B 44 08 66
03 46 1C 66 89 44 08 E8 30 FF 72 13 81 3E FE 7D 55 AA 0F 85 06 FF BC FA 7B 5A 5F 07 FA
FF E4 E8 1E 00 4F 70 65 72 61 74 69 6E 67 20 73 79 73 74 65 6D 20 6C 6F 61 64 20 65 72
72 6F 72 2E 0D 0A 5E AC B4 0E 8A 3E 62 04 B3 07 CD 10 3C 0A 75 F1 CD 18 F4 EB FD 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 19 16 9F 29 00 00 80 01 01 00 06 FE 3F 0E 3F 00 00 00 61 C8 03 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 AA
这是我的代码生成的内容:
EB 76 90 4D 53 44 4F 53 35 2E 30 00 02 04 04 00 02 00 02 00 00 F8 F2 00 3F 00 FF 00 3F
00 00 00 61 C8 03 00 80 00 29 7A E8 21 04 4E 4F 20 4E 41 4D 45 20 20 20 20 46 41 54 31
36 20 20 20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 E9 05 01 B4 0E 53 33 DB CD 10 5B C3 8A 07 3C 00 74 06 E8 EE FF 43 EB F4 C3
0D 4E 6F 20 42 50 42 3A 20 43 61 6E 27 74 20 62 6F 6F 74 20 75 73 69 6E 67 20 43 48 53
20 66 75 6E 63 74 69 6F 6E 73 00 50 B0 2E E8 BC FF 58 33 DB 8E 06 E4 01 F6 06 DC 01 02
75 42 F6 06 DC 01 04 75 07 80 3E E8 01 80 72 34 53 53 52 50 06 53 55 6A 10 8B F4 52 50
8A 16 E8 01 B8 00 42 F9 CD 13 8A EC 58 5A 8D 64 10 72 14 80 FD 00 75 0F 03 C5 83 D2 00
C3 BB 91 00 E8 78 FF F4 EB FD 83 3E 18 00 00 74 F0 52 50 8B CD F7 36 18 00 8B F2 03 D1
3B 16 18 00 76 06 8B 0E 18 00 2B CE 33 D2 F7 36 1A 00 88 16 E9 01 8B F8 8B D7 51 8A C1
8D 4C 01 C0 E6 06 0A CE 8A EA 8B 16 E8 01 B4 02 CD 13 59 73 15 80 FC 09 75 0A 49 EB DE
8A C4 04 30 E8 18 FF B4 00 CD 13 EB D1 58 5A 03 C1 83 D2 00 2B E9 74 07 C1 E1 09 03 D9
EB 94 C3 00 00 00 00 FA FC E8 00 00 5E 81 EE 85 01 2E 8B 84 E4 01 8E D8 8E C0 8E D0 2E
C7 84 7C 01 AF 01 2E 89 84 7E 01 B9 00 01 BF 00 00 F3 2E A5 2E FF AC 7C FF BC 00 0A FB
80 3E E8 01 FF 75 04 88 16 E8 01 83 06 E4 01 20 A1 E0 01 8B 16 E2 01 BD 02 00 E8 E9 FE
50 52 EB 74 90 00 00 00 00 00 00 00 00 00 00 00 D3 20 00 00 00 30 80 00 FF 00 68 41 00
40 09 FF 40 5A AC 04 00 00 AC 04 00 00 00 00 12 00 55 AA
这是从完全相同的 CF 卡中获取的,没有任何编辑/写入等正在发生,所以我很困惑为什么它们如此不同,但两者都以正确的 55 AA 字节结尾。当以这种方式访问卡上的 MBR 时,Windows 是否会损坏卡上的 MBR,或者是否发生了一些我不知道的其他奇怪的事情?
I'm writing a C#.Net app to run on windows that needs to take an image of a removable disk and chuck it onto a Linux Live USB. The Live USB is the inserted into the target machine and boots, on start up it runs a script which uses the dd command like so to flash it onto another drive:
dd if=/path/to/file/from/csharp/program of=/dev/sdX
The problem I am having is creating the image on the windows side. I have tried my Live Linux out with files I have created on a Linux system using dd and that works fine, but I need to be able to create these files from within a C#.Net application on Windows. I'd rather not have to rely on cygwin or some other dependency so tried to use the Win32 CreateFile function to open the physical device.
CreateFile is called with the first arg set to "\.\F:" (if F: is the drive I want to image), like so:
SafeFileHandle TheDevice = CreateFile(_DevicePath, (uint)FileAccess.Read, (uint)(FileShare.Write | FileShare.Read | FileShare.Delete), IntPtr.Zero, (uint)FileMode.Open, (uint)FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_SEQUENTIAL_SCAN, IntPtr.Zero);
if (TheDevice.IsInvalid)
{
throw new IOException("Unable to access drive. Win32 Error Code " + Marshal.GetLastWin32Error());
}
FileStream Dest = System.IO.File.Open(_SaveFile, FileMode.Create);
FileStream Src = new FileStream(TheDevice, FileAccess.Read);
Src.CopyTo(Dest);
Dest.Flush();
Src.Close();
Dest.Close();
But when the output file is dd'd back onto a disk using the Live Linux USB the result is not as expected (the disk isn't bootable etc, but from examining the output file in a hex editor, it looks like there is an MBR at the beginning etc).
Is this a problem with endianess or should I using something other than a FileStream to copy the data into the file.
Alternatively is there an example of dd for Windows source code (C# or C++, i've looked at the Delphi for http://www.chrysocome.net/dd and don't totally understand it or have a decent Delphi IDE to pick the code apart) so I can see how that works?
UPDATE/EDIT:
Here is a hex string of the first 512 Bytes that the dd output contains:
33 C0 FA 8E D8 8E D0 BC 00 7C 89 E6 06 57 8E C0 FB FC BF 00 06 B9 00 01 F3 A5 EA 1F 06
00 00 52 52 B4 41 BB AA 55 31 C9 30 F6 F9 CD 13 72 13 81 FB 55 AA 75 0D D1 E9 73 09 66
C7 06 8D 06 B4 42 EB 15 5A B4 08 CD 13 83 E1 3F 51 0F B6 C6 40 F7 E1 52 50 66 31 C0 66
99 E8 66 00 E8 21 01 4D 69 73 73 69 6E 67 20 6F 70 65 72 61 74 69 6E 67 20 73 79 73 74
65 6D 2E 0D 0A 66 60 66 31 D2 BB 00 7C 66 52 66 50 06 53 6A 01 6A 10 89 E6 66 F7 36 F4
7B C0 E4 06 88 E1 88 C5 92 F6 36 F8 7B 88 C6 08 E1 41 B8 01 02 8A 16 FA 7B CD 13 8D 64
10 66 61 C3 E8 C4 FF BE BE 7D BF BE 07 B9 20 00 F3 A5 C3 66 60 89 E5 BB BE 07 B9 04 00
31 C0 53 51 F6 07 80 74 03 40 89 DE 83 C3 10 E2 F3 48 74 5B 79 39 59 5B 8A 47 04 3C 0F
74 06 24 7F 3C 05 75 22 66 8B 47 08 66 8B 56 14 66 01 D0 66 21 D2 75 03 66 89 C2 E8 AC
FF 72 03 E8 B6 FF 66 8B 46 1C E8 A0 FF 83 C3 10 E2 CC 66 61 C3 E8 62 00 4D 75 6C 74 69
70 6C 65 20 61 63 74 69 76 65 20 70 61 72 74 69 74 69 6F 6E 73 2E 0D 0A 66 8B 44 08 66
03 46 1C 66 89 44 08 E8 30 FF 72 13 81 3E FE 7D 55 AA 0F 85 06 FF BC FA 7B 5A 5F 07 FA
FF E4 E8 1E 00 4F 70 65 72 61 74 69 6E 67 20 73 79 73 74 65 6D 20 6C 6F 61 64 20 65 72
72 6F 72 2E 0D 0A 5E AC B4 0E 8A 3E 62 04 B3 07 CD 10 3C 0A 75 F1 CD 18 F4 EB FD 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 19 16 9F 29 00 00 80 01 01 00 06 FE 3F 0E 3F 00 00 00 61 C8 03 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 AA
and here is what my code produces:
EB 76 90 4D 53 44 4F 53 35 2E 30 00 02 04 04 00 02 00 02 00 00 F8 F2 00 3F 00 FF 00 3F
00 00 00 61 C8 03 00 80 00 29 7A E8 21 04 4E 4F 20 4E 41 4D 45 20 20 20 20 46 41 54 31
36 20 20 20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 E9 05 01 B4 0E 53 33 DB CD 10 5B C3 8A 07 3C 00 74 06 E8 EE FF 43 EB F4 C3
0D 4E 6F 20 42 50 42 3A 20 43 61 6E 27 74 20 62 6F 6F 74 20 75 73 69 6E 67 20 43 48 53
20 66 75 6E 63 74 69 6F 6E 73 00 50 B0 2E E8 BC FF 58 33 DB 8E 06 E4 01 F6 06 DC 01 02
75 42 F6 06 DC 01 04 75 07 80 3E E8 01 80 72 34 53 53 52 50 06 53 55 6A 10 8B F4 52 50
8A 16 E8 01 B8 00 42 F9 CD 13 8A EC 58 5A 8D 64 10 72 14 80 FD 00 75 0F 03 C5 83 D2 00
C3 BB 91 00 E8 78 FF F4 EB FD 83 3E 18 00 00 74 F0 52 50 8B CD F7 36 18 00 8B F2 03 D1
3B 16 18 00 76 06 8B 0E 18 00 2B CE 33 D2 F7 36 1A 00 88 16 E9 01 8B F8 8B D7 51 8A C1
8D 4C 01 C0 E6 06 0A CE 8A EA 8B 16 E8 01 B4 02 CD 13 59 73 15 80 FC 09 75 0A 49 EB DE
8A C4 04 30 E8 18 FF B4 00 CD 13 EB D1 58 5A 03 C1 83 D2 00 2B E9 74 07 C1 E1 09 03 D9
EB 94 C3 00 00 00 00 FA FC E8 00 00 5E 81 EE 85 01 2E 8B 84 E4 01 8E D8 8E C0 8E D0 2E
C7 84 7C 01 AF 01 2E 89 84 7E 01 B9 00 01 BF 00 00 F3 2E A5 2E FF AC 7C FF BC 00 0A FB
80 3E E8 01 FF 75 04 88 16 E8 01 83 06 E4 01 20 A1 E0 01 8B 16 E2 01 BD 02 00 E8 E9 FE
50 52 EB 74 90 00 00 00 00 00 00 00 00 00 00 00 D3 20 00 00 00 30 80 00 FF 00 68 41 00
40 09 FF 40 5A AC 04 00 00 AC 04 00 00 00 00 12 00 55 AA
This was taken from exactly the same CF card without any editing/writing etc happening, so i'm confused as to why they are so different, but both end with the correct 55 AA bytes too. Does Windows mangle the MBR's on cards when they're accessed this way or is some other weird under the hood stuff happening that I'm not aware of?
发布评论
评论(2)
我认为你所拥有的应该可以工作 - 我自己使用可启动软盘映像尝试过这一点(使用 ImDisk),生成的文件与原始图像是相同的二进制文件。
为了完整起见,这里是我使用的代码(完整):
如果这不起作用,那么它似乎表明:
最可能的罪魁祸首是步骤 2。您对生成的磁盘映像到底做了什么?
更新:这是写在评论中的,但为了完整起见,我想我会将其添加到我的答案中 - 看起来发生的情况是正在写入磁盘第一个分区的内容,相反,我们需要的是整个磁盘的内容。
当您查看第二个十六进制字符串(由示例代码生成的字符串)时,例如 HxD 我们看到这个:
在我看来,这就像 FAT16 分区的引导扇区 - 存在弦的开头附近的“MSDOS5.0”、“NO NAME”和“FAT16”是一个致命的泄露。
将其与第一个十六进制字符串(由 dd 生成的字符串)的输出进行比较:
我们看到一些在我看来很像 主引导记录。为什么?因为在 MBR 中,所有前 440 个字节都是引导代码,与包含独特 BIOS 参数块的 FAT 引导扇区不同(上面看起来像垃圾,但如果你将其通过反汇编程序,你会得到看起来像有效 16 位的东西代码)。
此外,这两个看起来都是有效且完全不同的引导扇区(带有错误消息)。编程错误不可能“破坏”一个看起来像另一个——它一定只是读取了错误的内容。
为了让 CreateFile 返回磁盘而不是分区,您只需向其传递一个不同的字符串,例如 @"\\.\PhysicalDrive0"打开第一个物理磁盘。
请参阅:
I think what you have should work - I've tried this myself using a bootable floppy disk image (mounted as a virtual drive using ImDisk) and the resulting file is binary identical to the original image.
For completeness here is the code I used (in its entirity):
If this doesn't work then it seems to indicate that:
The most likely culprit is step 2. What exactly is it that you are doing with the resulting disk image?
Update: This is written in the comments, but for completeness I thought I'd add it to my answer - it looks like whats happening is that the contents of the first partition of the disk is being written, when instead what is wanted is the contents of the entire disk.
When you take a look at the second hex string (the one produced by sample code) in something like HxD we see this:
This looks to me like the boot sector of a FAT16 partition - the presence of the strings "MSDOS5.0", "NO NAME" and "FAT16" near the start is a dead giveaway.
Compare this to the output of the first hex string (the one produced by dd):
And we see something that looks to me a lot like a master boot record. Why? Because in the MBR all of the first 440 bytes is boot code, unlike a FAT boot sector which contains the distinctive bios parameter block (it looks like garbage above, but if you put that through a disassembler you get something that looks like valid 16 bit code).
Also, both of those look like valid and completely different boot sectors (complete with error messages). There is no way that a programming error could have "mangled" one to look like the other - it must just be that the wrong thing is being read.
In order to get
CreateFile
to return the disk instead of the partition it looks like you just need to pass it a different string, for example@"\\.\PhysicalDrive0"
opens the first physical disk.See:
这就是我写的内容,用于获取给定驱动器号的 \.\PhysicalDriveX 路径。如果将驱动器号传递到此中并获取返回值并将其作为第一个参数传递到 CreateFile 中,我现在应该得到类似于 Linux 下 dd 的内容。
This is what i've written to do get the \.\PhysicalDriveX path for a given drive letter. If Pass the drive letter into this and take the return value and pass into CreateFile as the first Param I should now get something similar to dd under Linux.