commit fa91d70fef2a6b9f27793545f3e0d3d1bdd2c7a8
author Jiyong Park <jiyong@google.com> Mon Oct 18 23:51:39 2021 +0900
committer Jiyong Park <jiyong@google.com> Wed Oct 27 01:34:39 2021 +0900
tree 2ba37df1ad41a6e99b7dcdaa6e7d3b7834a3b87b
parent 779daa97640c47770836efa9a888e0d5a00a5c52

Send logd logs from VM to host

When the debug level of a VM is not "none", logd logs from the VM is
sent to the host. This is done by running the VM with another virtual
console and running logcat as a daemon process whose output is set to
the new virtual console device. The launch of the daemon process is
controlled by microdroid. It starts the process only when the debug
level is set to above "none".

For now, the virtual console device is backed by the same file
descriptor as the kernel console logs. A follow-up change will introduce
a new dedicated file descriptor.

Bug: 200914564
Test: start microdroid using the `vm` tool. logcat logs are shown in
stdout.

Change-Id: I1748d30c5c997cda73f7b9f082ca84b0b3d25f1e