How to clear file content without closing its handle in kernel mode

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Hello, I have a file that I use to save data when the system is running and I wish to save data to it but before saving, I want to erase its old content so at the end I can only have the latest content in the file. For some reason I would like to achieve that without close the file handle.
I first thought about using ZwSetInformationFile to set the size to 0 but I remember that its not recommended to play with file size so I was wondering If any of you that have been down the path could provide any help.

I awaiting for a response.

Thank you.

What I have tried:

I have already tired ZwSetInformationFile where my intention is to change the file size but I'm not sure that the way to do it.

Posted 28-Feb-16 18:16pm

Wshwilfried

Updated 28-Feb-16 22:20pm

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Richard MacCutchan · Answer 1 · 2016-02-28T22:20:00

Solution 1

You can use the FILE_OVERWRITE option on your call to ZwCreateFile routine (Windows Drivers)[^].

Posted 28-Feb-16 22:20pm

Richard MacCutchan

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Wshwilfried 1-Mar-16 19:16pm

Thank you, I'll try that.

Wshwilfried 6-Mar-16 21:10pm

I just tried That but it is not giving what I want also it isn't much different from FILE_OVERWRITE_IF that I was using before posting my question. What I need is that when calling ZwWriteFile the file content get cleared before the new buffer get written to the corresponding file.

Wshwilfried 6-Mar-16 21:50pm

I think I found it, I just Set the byte offset to 0 when calling ZwWritefile and since the buffers are of the same size it always get updated.