guestFullName value pushed to hypervisor longer can be longer than 128 bytes

[jepio]

Describe the bug

Users have reported that when running a Flatcar Container Linux VM on VMware, the "guestFullName" property pushed to the hypervisor can be longer than 128 bytes which results in hitting this bug: https://kb.vmware.com/s/article/95714?lang=en_US&queryTerm=%20KB%2095714.

Here's an example of what is pushed:

guestFullName = "Linux 6.1.77-flatcar Flatcar Container Linux by Kinvolk 3815.2.0 3815.2.0 2024-02-12-2039 Flatcar Container Linux by Kinvolk 3815.2.0 (Oklo) cpe:2.3:o:flatcar-linux:flatcar_linux:3815.2.0:::::::*"

A lot of the information being pushed is redundant, eg. PRETTY_NAME contains NAME+VERSION+VERSION_ID, CPE_NAME is not immediately interesting to see in the Web UI, etc.

Reproduction steps

1. Deploy a Flatcar VM https://www.flatcar.org/docs/latest/installing/cloud/vmware/
2. Query metadata about the guest from the hypervisor: vim-cmd vmsvc/get.guest 1

...

Expected behavior

guestFullName is <128 bytes and does not contain redundant data.

Additional context

Related issues:

• VMtools can't get correct guestID for Flatcar 3760&3815 on ESXi 7.0.3 flatcar/Flatcar#1365
• guestFullName exceeds 128 characters causing vCenter Server disconnects in Cloud Director flatcar/Flatcar#1370

Would you be able to add proper detection of Flatcar to open-vm-tools, and shorten the pushed string? "Flatcar Container Linux" would be nice.