Silently fails and generates short coredump and creates confustion

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I get the following error print when provided with invalid VMRS file.

`> .\vm2core.exe "test1.VMRS" .\test1.vmcore

The system cannot find the file specified. `

The snapshot file exists but it is invalid input as it was generated when VM was in turned off state.

Hello, I appreciate that this tool exists, it has helped me out of a bind! But I wanted to give a bit of feedback. The vmcoreinfo note which is generated for the ELF file is fake, as mentioned in the code:

    // Fill fake data in VMCOREINFO to keep crash tool happy
    // TODO: Is it possible to get real data from state file ?

Unfortunately, at least with the crash + kernel versions I tested (honestly, I can't recall the exact details as it was months ago), fake data does not keep crash happy. Crash relies on vmcoreinfo to find things like the page tables, important data structures, and to verify the sizes of important data structures. And other tools like drgn similarly expect to read real data from it.

To work around this, I needed to find the vmcoreinfo data from the generated ELF file, and then patch the ELF file with the correct data.

It is possible to get real data from the memory image, but it is of course quite slow -- you need to scan the memory for well-known contents like OSRELEASE=. Given that vm2core already needs to read and write each block of memory, maybe it wouldn't be a huge additional runtime slowdown to do the search? It could certainly be an opt-in feature if necessary. Vmcoreinfo will always start at a PAGE_SIZE aligned address, and it will always start with OSRELEASE=. That may help speed things up. See here for the linux code generating it.

I have a script which wraps strings to find the correct vmcoreinfo and output it to a file, to give you the general idea of what needs to be done. It doesn't even take into account the page-aligned restriction.