Runtime Probe is essentially a command line tool that consumes the probe syntax and outputs the probe result.
This command line tool will gradually replace fields in HWID (i.e. less fields will be encoded into HWID) as it reflects the status of a device in a more timely approach.
Currently, the reported data are purely hardware information. For example, the model of storage, the remaining capacity of battery, the screen resolution..etc.
To serve clients that are not able to call command line directly, we offer a simple, restricted DBus interface with only one method (with minijail0, seccomp policy and dbus/org.chromium.RuntimeProbe.conf). As this CLI tool poses itself as a one-shot call tool, just like ping command, the DBus interface is on-demand and expected to exit after one call. There is a long-term solution effort in parallel. Once that is ready, we might turn off the DBus interface, this is tracked in b/120826476.
To better reflect hardware configuration on users’ system, we need a tool in release image that is able to reflect the truth of the moment in the field.
Traditionally, this need has been satisfied by factory's probe framework , however, we have seen more and more requests from partners to switch component after devices left factory process.
It is related to the evolution of HWID. However, instead of going into details on the complicated plan, we would like to use an example to let the reader get a high level concept.
Let‘s look into a typical scenario here: After years’ love into the Chromebook, a user has one of the DRAM broken in slots, and would like to replace it. However, the original part is already EOL (End Of Life), ODM has no choice but to pick another part from the AVL ( Approved Vendor List ) . While this new DRAM is installed, the original probe result in factory is violated. Hence, even after factory process, we would like to get the probe result to reflect the truth of the moment under release image. Runtime is used to convey the concept of dynamic.
The code is still underdevelopment, will update when it is ready for use.