file-restore-daemon: add binary with virtio-vsock API server

Implements the base of a small daemon to run within a file-restore VM.

The binary spawns an API server on a virtio-vsock socket, listening for
connections from the host. This happens mostly manually via the standard
Unix socket API, since tokio/hyper do not have support for vsock built
in. Once we have the accept'ed file descriptor, we can create a
UnixStream and use our tower service implementation for that.

The binary is deliberately not installed in the usual $PATH location,
since it shouldn't be executed on the host by a user anyway.

For now, only the API calls 'status' and 'stop' are implemented, to
demonstrate and test proxmox::api functionality.

Authorization is provided via a custom ApiAuth only checking a header
value against a static /ticket file.

Since the REST server implementation uses the log!() macro, we can
redirect its output to stdout by registering env_logger as the logging
target. env_logger is already in our dependency tree via zstd/bindgen.

Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

src/api2/types/file_restore.rs

@@ -0,0 +1,12 @@
+use serde::{Deserialize, Serialize};
+use proxmox::api::api;
+
+#[api()]
+#[derive(Serialize, Deserialize)]
+#[serde(rename_all = "kebab-case")]
+/// General status information about a running VM file-restore daemon
+pub struct RestoreDaemonStatus {
+    /// VM uptime in seconds
+    pub uptime: i64,
+}
+

src/api2/types/mod.rs

@@ -34,6 +34,9 @@ pub use userid::{PROXMOX_TOKEN_ID_SCHEMA, PROXMOX_TOKEN_NAME_SCHEMA, PROXMOX_GRO
 mod tape;
 pub use tape::*;
 
+mod file_restore;
+pub use file_restore::*;
+
 // File names: may not contain slashes, may not start with "."
 pub const FILENAME_FORMAT: ApiStringFormat = ApiStringFormat::VerifyFn(|name| {
     if name.starts_with('.') {