Distinguish the process AppScope state (Unscoped/Attached/Detached)

[michalbiesek]

Currently, in our model, we could distinguish the state of whether our library is loaded or not.
With the detach functionality we have a new state: our library can be loaded but we are not sending any data.
So essentially in context of the AppScope, process can be in three states:

• Unscoped (our library is not loaded)
• Attached (our library is loaded and we actively send the data to the destination place - we are hooked)
• Detached (our library is loaded and we do not send the data to the destination place - we are unhooked)

See the state diagram below

Scenario 1 Attach to running application

stateDiagram-v2
    ProcStart: Process Start
    State1: AppScope is not loaded
    State2: AppScope is loaded
    state State1 {
    ProcStart --> Unscoped
    Unscoped --> Attached: ldscope -a
    }
    state State2 {
    Attached --> Detached: ldscope -d
    Detached --> Attached: ldscope -a
    }

Loading

Scenario 2 Run scoped application

stateDiagram-v2
    State1: AppScope is not loaded
    State2: AppScope is loaded
    state State1 {
    * --> Attached :ldscope ./foo_process
    }
    state State2 {
    Attached --> Detached: ldscope -d
    Detached --> Attached: ldscope -a
    }

Loading

We should be able to distinguish these three states with for example scope ps without extensive privileges like ptrace

[michalbiesek]

Test instructions:

• Start example process (e.g. htop)
• Perform attach via e.g. ldscope -a <htop_pid>
• Run sudo scope ps
  Example output:

sudo scope ps
ID	PID    	USER      COMMAND	STATE
1 	3230690	foouser	  htop   	Attached

• Perform detach via e.g. ldscope -d <htop_pid>
• Wait several seconds ~5 to ensure that the dynamic configuration file was consumed
• Run sudo scope ps
  Example output:

sudo scope ps
ID	PID    	USER      COMMAND	STATE
1 	3230690	foouser	  htop   	Detached

[michalbiesek]

Closing since the work will be continued in #1108