[202205][systemd-sonic-generator] Fix overlapping strings being passed to str…

[stepanblyschak]

Backport #13647

Why I did it

Fix an issue that services do not start automatically on first boot and start only after hostcfgd enables them.
This is due to a bug in systemd-sonic-generator:

admin@arc-switch1004:~$ /usr/lib/systemd/system-generators/systemd-sonic-generator dir
Failed to open file /usr/lib/systemd/system/database.servcee
Error parsing targets for database.servcee
Error parsing database.servcee
Failed to open file /usr/lib/systemd/system/bgp.servcee
Error parsing targets for bgp.servcee
Error parsing bgp.servcee
Failed to open file /usr/lib/systemd/system/lldp.servcee
Error parsing targets for lldp.servcee
Error parsing lldp.servcee
Failed to open file /usr/lib/systemd/system/swss.servcee
Error parsing targets for swss.servcee
Error parsing swss.servcee
Failed to open file /usr/lib/systemd/system/teamd.servcee
Error parsing targets for teamd.servcee
Error parsing teamd.servcee
Failed to open file /usr/lib/systemd/system/syncd.servcee
Error parsing targets for syncd.servcee
Error parsing syncd.servcee

A wrong file name is generated (e.g database.servcee).

How I did it

Fixed overlapping strings being passed to strcpy/strcat that receive restirct* pointers (strings should not overlap).

How to verify it

Perform first boot and observe services start immidiatelly after boot.

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

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

Description for the changelog

Ensure to add label/tag for the feature raised. example - PR#2174 under sonic-utilities repo. where, Generic Config and Update feature has been labelled as GCU.

Link to config_db schema for YANG module changes

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