In order to better manage per-profile data resources on the client, add methods
to the LocalBackend to support creation of per-profile directory structures in
local storage. These methods build on the existing TailscaleVarRoot config, and
have the same limitation (i.e., if no local storage is available, it will
report an error when used).
The immediate motivation is to support netmap caching, but we can also use this
mechanism for other per-profile resources including pending taildrop files and
Tailnet Lock authority caches.
This commit only adds the directory-management plumbing; later commits will
handle migrating taildrop, TKA, etc. to this mechanism, as well as caching
network maps.
Updates #12639
Change-Id: Ia75741955c7bf885e49c1ad99f856f669a754169
Signed-off-by: M. J. Fromberger <fromberger@tailscale.com>
M. J. Fromberger
ce12863ee5