Postulates

Here are a few principles that must be taken into account while developing CRIU.

• All shared resources must be restored by the task with the lowest PID among the group to avoid deadlocks.
• No operations with file paths in restorer blob — task has restored its fs (cwd and root) and may see a different tree.
• In dumping code, any fork()+exec() should be done using the cr_system() helper to avoid interfering with victim task tracing.

Protobuf images compatibility

To retain backward compatibility of protobuf image files, follow these rules:

• Don't change the numeric tags for any existing fields.
• Any new fields that you add should be optional or repeated.
• Non-required fields can be removed, as long as the tag number is not used again in your updated message type.

For more info, see protobuf messages updating guide.

External links

• https://developers.google.com/protocol-buffers/docs/proto#updating