reset-factory more robust with exec reboot

[MichaelWangSmci]

Why I did it

reset-factory dose not flush config_db.json when executed from a console terminal.

Work item tracking

• Microsoft ADO (number only): None

How I did it

Replace "reboot" with "exec reboot" in the reset-factory script.

How to verify it

Create a VLAN and save the config.
Execute reset-factory from a console terminal.
After reboot check the VLAN should not exist.

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106
• 202111
• 202205
• 202211
• 202305

Tested branch (Please provide the tested image version)

• master

Description for the changelog

reset-factory more robust with exec reboot

Link to config_db schema for YANG module changes

A picture of a cute animal (not mandatory but encouraged)

[lguohan]

what is the difference between exec reboot and reboot. the explanation is not quite clear.

[MichaelWangSmci]

what is the difference between exec reboot and reboot. the explanation is not quite clear.

I found that if run "reset-factory" in a console terminal, then after reboot the config_db.json is not reset.
And if replace "reboot" with "exec reboot" in "reset-factory", then config_db.json is reset as expected.
I guess this is because "reset-factory" calls "reboot" which is actually "/usr/local/bin/reboot", and it uses exec to do reboot, makes "reset-factory" lost it's change on config_db.json.
"exec reboot" can trigger config_db.json flushed to disk when the process is replaced with "/usr/local/bin/reboot".