microdroid_manager executes a task via microdroid_launcher

Task can be one of "executable" or "microdroid_launcher".
When it is a microdroid_launcher task, microdroid_manager find the
target library in /mnt/apk/lib/{abi}/, and then executes it via
microdroid_launcher.

Bug: 186396080
Test: MicrodroidHostTestCases
Test: /system/bin/microdroid_manager in microdroid launched with
   default configuration.
   it should run testapk's MicrodroidTestNativeLib.so
Change-Id: I065f5c5d789e6a96fd658a52ed8533f42b1cbc42
diff --git a/microdroid/payload/config/src/lib.rs b/microdroid/payload/config/src/lib.rs
new file mode 100644
index 0000000..6dc127b
--- /dev/null
+++ b/microdroid/payload/config/src/lib.rs
@@ -0,0 +1,89 @@
+// Copyright 2021, The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! VM Payload Config
+
+use serde::{Deserialize, Serialize};
+
+/// VM payload config
+#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
+pub struct VmPayloadConfig {
+    /// OS config. Default: "microdroid"
+    #[serde(default)]
+    pub os: OsConfig,
+
+    /// Task to run in a VM
+    #[serde(default)]
+    pub task: Option<Task>,
+
+    /// APEXes to activate in a VM
+    #[serde(default)]
+    pub apexes: Vec<ApexConfig>,
+}
+
+/// OS config
+#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
+pub struct OsConfig {
+    /// The name of OS to use
+    pub name: String,
+}
+
+impl Default for OsConfig {
+    fn default() -> Self {
+        Self { name: "microdroid".to_owned() }
+    }
+}
+
+/// Payload's task can be one of plain executable
+/// or an .so library which can be started via /system/bin/microdroid_launcher
+#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
+pub enum TaskType {
+    /// Task's command indicates the path to the executable binary.
+    #[serde(rename = "executable")]
+    Executable,
+    /// Task's command indicates the .so library in /mnt/apk/lib/{arch}
+    #[serde(rename = "microdroid_launcher")]
+    MicrodroidLauncher,
+}
+
+/// Task to run in a VM
+#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
+pub struct Task {
+    /// Decides how to execute the command: executable(default) | microdroid_launcher
+    #[serde(default, rename = "type")]
+    pub type_: TaskType,
+
+    /// Command to run
+    /// - For executable task, this is the path to the executable.
+    /// - For microdroid_launcher task, this is the name of .so
+    pub command: String,
+
+    /// Args to the command
+    #[serde(default)]
+    pub args: Vec<String>,
+}
+
+impl Default for TaskType {
+    fn default() -> TaskType {
+        TaskType::Executable
+    }
+}
+
+/// APEX config
+/// For now, we only pass the name of APEX.
+#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
+pub struct ApexConfig {
+    /// The name of APEX
+    pub name: String,
+}