Implement RPC for reading & writing to app cache file

- Implement RPC for writing to a file in a test runner / guest VM.
- Implement RPC for getting app cache directory
- Implement RPC for restarting the app in a test runner / guest vm
- Implement RPC for starting the app in a test runner / guest vm
- Implement RPC for stopping the app in a test runner / guest vm
- Implement `find_cache_traces` on Window & macOS

8 files changed, 251 insertions, 54 deletions

diff --git a/test/test-manager/src/tests/tunnel_state.rs b/test/test-manager/src/tests/tunnel_state.rs
index eb78828fd0..176127d7c5 100644
--- a/test/test-manager/src/tests/tunnel_state.rs
+++ b/test/test-manager/src/tests/tunnel_state.rs
@@ -1,6 +1,6 @@
 use super::helpers::{
-    self, connect_and_wait, get_tunnel_state, send_guest_probes, set_relay_settings,
-    unreachable_wireguard_tunnel, wait_for_tunnel_state,
+    self, connect_and_wait, disconnect_and_wait, get_tunnel_state, send_guest_probes,
+    set_relay_settings, unreachable_wireguard_tunnel, wait_for_tunnel_state,
 };
 use super::{ui, Error, TestContext};
 use crate::assert_tunnel_state;
@@ -335,3 +335,33 @@ pub async fn test_connected_state(
 
     Ok(())
 }
+
+/// Verify that the app defaults to the connecting state if it is started with a
+/// corrupt state cache.
+#[test_function]
+pub async fn test_connecting_state_when_corrupted_state_cache(
+    _: TestContext,
+    rpc: ServiceClient,
+    mut mullvad_client: ManagementServiceClient,
+) -> Result<(), Error> {
+    // Enter the disconnected state. Normally this would be preserved when
+    // restarting the app, i.e. the user would still be disconnected after a
+    // successfull restart. However, as we will intentionally corrupt the state
+    // target cache the user should end up in the connecting/connected state,
+    // *not in the disconnected state, upon restart.
+    disconnect_and_wait(&mut mullvad_client).await?;
+
+    // Stopping the app should write to the state target cache.
+    log::info!("Stopping the app");
+    rpc.restart_app().await?;
+
+    // Intentionally corrupt the state cache
+    todo!("Intentionally corrupt the state cache");
+    // Start a leak monitor
+    todo!("Start a leak monitor");
+    // Start the app & make sure that we start in the 'connecting state'. The
+    // side-effect of this is that no network traffic is allowed to leak.
+    todo!("Start the app");
+    assert_tunnel_state!(&mut mullvad_client, TunnelState::Connecting { .. });
+    Ok(())
+}
diff --git a/test/test-rpc/src/client.rs b/test/test-rpc/src/client.rs
index 6be77afb40..acc462dd60 100644
--- a/test/test-rpc/src/client.rs
+++ b/test/test-rpc/src/client.rs
@@ -151,6 +151,13 @@ impl ServiceClient {
             .await?
     }
 
+    /// Returns path of Mullvad app cache directorie on the test runner.
+    pub async fn find_mullvad_app_cache_dir(&self) -> Result<PathBuf, Error> {
+        self.client
+            .get_mullvad_app_cache_dir(tarpc::context::current())
+            .await?
+    }
+
     /// Send TCP packet
     pub async fn send_tcp(
         &self,
@@ -213,6 +220,34 @@ impl ServiceClient {
             .await?
     }
 
+    pub async fn restart_app(&self) -> Result<(), Error> {
+        let _ = self.client.restart_app(tarpc::context::current()).await?;
+        Ok(())
+    }
+
+    /// Stop the app.
+    ///
+    /// Shuts down a running app, making it disconnect from any current tunnel
+    /// connection and making it write to caches.
+    ///
+    /// # Note
+    /// This function will return *after* the app has been stopped, thus
+    /// blocking execution until then.
+    pub async fn stop_app(&self) -> Result<(), Error> {
+        let _ = self.client.stop_app(tarpc::context::current()).await?;
+        Ok(())
+    }
+
+    /// Start the app.
+    ///
+    /// # Note
+    /// This function will return *after* the app has been start, thus
+    /// blocking execution until then.
+    pub async fn start_app(&self) -> Result<(), Error> {
+        let _ = self.client.start_app(tarpc::context::current()).await?;
+        Ok(())
+    }
+
     pub async fn set_daemon_log_level(
         &self,
         verbosity_level: mullvad_daemon::Verbosity,
@@ -247,6 +282,17 @@ impl ServiceClient {
             .await?
     }
 
+    pub async fn write_file(&self, dest: String, bytes: Vec<u8>) -> Result<(), Error> {
+        log::debug!(
+            "Writing {bytes} bytes to \"{file}\"",
+            bytes = bytes.len(),
+            file = dest
+        );
+        self.client
+            .write_file(tarpc::context::current(), dest, bytes)
+            .await?
+    }
+
     pub async fn reboot(&mut self) -> Result<(), Error> {
         log::debug!("Rebooting server");
 
diff --git a/test/test-rpc/src/lib.rs b/test/test-rpc/src/lib.rs
index 6968a3c613..65ccb2fb7a 100644
--- a/test/test-rpc/src/lib.rs
+++ b/test/test-rpc/src/lib.rs
@@ -120,6 +120,8 @@ mod service {
         /// Returns all Mullvad app files, directories, and other data found on the system.
         async fn find_mullvad_app_traces() -> Result<Vec<AppTrace>, Error>;
 
+        async fn get_mullvad_app_cache_dir() -> Result<PathBuf, Error>;
+
         /// Send TCP packet
         async fn send_tcp(
             interface: Option<String>,
@@ -149,6 +151,15 @@ mod service {
         /// Perform DNS resolution.
         async fn resolve_hostname(hostname: String) -> Result<Vec<SocketAddr>, Error>;
 
+        /// Restart the Mullvad VPN application.
+        async fn restart_app() -> Result<(), Error>;
+
+        /// Stop the Mullvad VPN application.
+        async fn stop_app() -> Result<(), Error>;
+
+        /// Start the Mullvad VPN application.
+        async fn start_app() -> Result<(), Error>;
+
         /// Sets the log level of the daemon service, the verbosity level represents the number of
         /// `-v`s passed on the command line. This will restart the daemon system service.
         async fn set_daemon_log_level(
@@ -161,6 +172,9 @@ mod service {
         /// Copy a file from `src` to `dest` on the test runner.
         async fn copy_file(src: String, dest: String) -> Result<(), Error>;
 
+        /// Write arbitrary bytes to some file `dest` on the test runner.
+        async fn write_file(dest: String, bytes: Vec<u8>) -> Result<(), Error>;
+
         async fn reboot() -> Result<(), Error>;
 
         async fn set_mullvad_daemon_service_state(on: bool) -> Result<(), Error>;
diff --git a/test/test-runner/Cargo.toml b/test/test-runner/Cargo.toml
index 2c431ffa49..64461d76aa 100644
--- a/test/test-runner/Cargo.toml
+++ b/test/test-runner/Cargo.toml
@@ -18,7 +18,7 @@ serde_json = { workspace = true }
 tokio-serde = { workspace = true }
 
 libc = "0.2"
-chrono = { workspace = true }
+chrono = { workspace = true, features = ["serde"] }
 
 test-rpc = { path = "../test-rpc" }
 mullvad-paths = { path = "../../mullvad-paths" }
diff --git a/test/test-runner/src/app.rs b/test/test-runner/src/app.rs
index 43aca23abb..f4e1fc3c53 100644
--- a/test/test-runner/src/app.rs
+++ b/test/test-runner/src/app.rs
@@ -1,5 +1,5 @@
 use chrono::{DateTime, Utc};
-use std::path::Path;
+use std::path::{Path, PathBuf};
 
 use test_rpc::{AppTrace, Error};
 
@@ -14,21 +14,18 @@ pub fn find_traces() -> Result<Vec<AppTrace>, Error> {
         Error::Syscall
     })?;
 
-    let mut traces = vec![
+    let caches = find_cache_traces()?;
+    let traces = vec![
         Path::new(r"C:\Program Files\Mullvad VPN"),
         // NOTE: This only works as of `499c06decda37dc639e5f` in the Mullvad app.
         // Older builds have no way of silently fully uninstalling the app.
         Path::new(r"C:\ProgramData\Mullvad VPN"),
         // NOTE: Works as of `4116ebc` (Mullvad app).
         &settings_dir,
+        &caches,
     ];
 
-    filter_non_existent_paths(&mut traces)?;
-
-    Ok(traces
-        .into_iter()
-        .map(|path| AppTrace::Path(path.to_path_buf()))
-        .collect())
+    Ok(existing_paths(&traces))
 }
 
 #[cfg(target_os = "linux")]
@@ -36,10 +33,11 @@ pub fn find_traces() -> Result<Vec<AppTrace>, Error> {
     // TODO: Check GUI data
     // TODO: Check temp data
 
-    let mut traces = vec![
+    let caches = find_cache_traces()?;
+    let traces = vec![
         Path::new(r"/etc/mullvad-vpn/"),
         Path::new(r"/var/log/mullvad-vpn/"),
-        Path::new(r"/var/cache/mullvad-vpn/"),
+        &caches,
         Path::new(r"/opt/Mullvad VPN/"),
         // management interface socket
         Path::new(r"/var/run/mullvad-vpn"),
@@ -55,12 +53,11 @@ pub fn find_traces() -> Result<Vec<AppTrace>, Error> {
         Path::new(r"/usr/share/fish/vendor_completions.d/mullvad.fish"),
     ];
 
-    filter_non_existent_paths(&mut traces)?;
+    Ok(existing_paths(&traces))
+}
 
-    Ok(traces
-        .into_iter()
-        .map(|path| AppTrace::Path(path.to_path_buf()))
-        .collect())
+pub fn find_cache_traces() -> Result<PathBuf, Error> {
+    mullvad_paths::get_cache_dir().map_err(|error| Error::FileSystem(error.to_string()))
 }
 
 #[cfg(target_os = "macos")]
@@ -68,10 +65,11 @@ pub fn find_traces() -> Result<Vec<AppTrace>, Error> {
     // TODO: Check GUI data
     // TODO: Check temp data
 
-    let mut traces = vec![
+    let caches = find_cache_traces()?;
+    let traces = vec![
         Path::new(r"/Applications/Mullvad VPN.app/"),
         Path::new(r"/var/log/mullvad-vpn/"),
-        Path::new(r"/Library/Caches/mullvad-vpn/"),
+        &caches,
         // management interface socket
         Path::new(r"/var/run/mullvad-vpn"),
         // launch daemon
@@ -84,26 +82,16 @@ pub fn find_traces() -> Result<Vec<AppTrace>, Error> {
         Path::new(r"/usr/local/share/fish/vendor_completions.d/mullvad.fish"),
     ];
 
-    filter_non_existent_paths(&mut traces)?;
-
-    Ok(traces
-        .into_iter()
-        .map(|path| AppTrace::Path(path.to_path_buf()))
-        .collect())
+    Ok(existing_paths(&traces))
 }
 
-fn filter_non_existent_paths(paths: &mut Vec<&Path>) -> Result<(), Error> {
-    for i in (0..paths.len()).rev() {
-        let path_exists = paths[i].try_exists().map_err(|error| {
-            log::error!("Failed to check whether path exists: {error}");
-            Error::Syscall
-        })?;
-        if !path_exists {
-            paths.swap_remove(i);
-            continue;
-        }
-    }
-    Ok(())
+/// Find all present app traces on the test runner.
+fn existing_paths(paths: &[&Path]) -> Vec<AppTrace> {
+    paths
+        .iter()
+        .filter(|&path| path.try_exists().is_ok_and(|exists| exists))
+        .map(|path| AppTrace::Path(path.to_path_buf()))
+        .collect()
 }
 
 pub async fn make_device_json_old() -> Result<(), Error> {
diff --git a/test/test-runner/src/main.rs b/test/test-runner/src/main.rs
index ebf0d1e474..259ccdbab6 100644
--- a/test/test-runner/src/main.rs
+++ b/test/test-runner/src/main.rs
@@ -3,7 +3,7 @@ use logging::LOGGER;
 use std::{
     collections::{BTreeMap, HashMap},
     net::{IpAddr, SocketAddr},
-    path::Path,
+    path::{Path, PathBuf},
 };
 
 use tarpc::context;
@@ -114,6 +114,13 @@ impl Service for TestServer {
         app::find_traces()
     }
 
+    async fn get_mullvad_app_cache_dir(
+        self,
+        _: context::Context,
+    ) -> Result<PathBuf, test_rpc::Error> {
+        app::find_cache_traces()
+    }
+
     async fn send_tcp(
         self,
         _: context::Context,
@@ -140,7 +147,7 @@ impl Service for TestServer {
         interface: Option<String>,
         destination: IpAddr,
     ) -> Result<(), test_rpc::Error> {
-        net::send_ping(interface.as_ref().map(String::as_str), destination).await
+        net::send_ping(interface.as_deref(), destination).await
     }
 
     async fn geoip_lookup(
@@ -219,6 +226,20 @@ impl Service for TestServer {
         logging::get_mullvad_app_logs().await
     }
 
+    async fn restart_app(self, _: context::Context) -> Result<(), test_rpc::Error> {
+        sys::restart_app().await
+    }
+
+    /// Stop the Mullvad VPN application.
+    async fn stop_app(self, _: context::Context) -> Result<(), test_rpc::Error> {
+        sys::stop_app().await
+    }
+
+    /// Start the Mullvad VPN application.
+    async fn start_app(self, _: context::Context) -> Result<(), test_rpc::Error> {
+        sys::start_app().await
+    }
+
     async fn set_daemon_log_level(
         self,
         _: context::Context,
@@ -248,6 +269,25 @@ impl Service for TestServer {
         Ok(())
     }
 
+    /// Write a slice as the entire contents of a file.
+    ///
+    /// See the documention of [`tokio::fs::write`] for details of the behavior.
+    async fn write_file(
+        self,
+        _: context::Context,
+        dest: PathBuf,
+        bytes: Vec<u8>,
+    ) -> Result<(), test_rpc::Error> {
+        tokio::fs::write(&dest, bytes).await.map_err(|error| {
+            log::error!(
+                "Failed to write to \"{dest}\": {error}",
+                dest = dest.display()
+            );
+            test_rpc::Error::Syscall
+        })?;
+        Ok(())
+    }
+
     async fn reboot(self, _: context::Context) -> Result<(), test_rpc::Error> {
         sys::reboot()
     }
diff --git a/test/test-runner/src/net.rs b/test/test-runner/src/net.rs
index f40aece4c9..a4a7a2db47 100644
--- a/test/test-runner/src/net.rs
+++ b/test/test-runner/src/net.rs
@@ -35,7 +35,7 @@ pub async fn send_tcp(
         };
 
         #[cfg(target_os = "macos")]
-        sock.bind_device_by_index(Some(interface_index))
+        sock.bind_device_by_index_v4(Some(interface_index))
             .map_err(|error| {
                 log::error!("Failed to set IP_BOUND_IF on socket: {error}");
                 test_rpc::Error::SendTcp
@@ -102,7 +102,7 @@ pub async fn send_udp(
         };
 
         #[cfg(target_os = "macos")]
-        sock.bind_device_by_index(Some(interface_index))
+        sock.bind_device_by_index_v4(Some(interface_index))
             .map_err(|error| {
                 log::error!("Failed to set IP_BOUND_IF on socket: {error}");
                 test_rpc::Error::SendUdp
diff --git a/test/test-runner/src/sys.rs b/test/test-runner/src/sys.rs
index 93d148a2b5..cc89205425 100644
--- a/test/test-runner/src/sys.rs
+++ b/test/test-runner/src/sys.rs
@@ -193,16 +193,102 @@ ExecStart=/usr/bin/mullvad-daemon --disable-stdout-timestamps {verbosity}"#
         .await
         .map_err(|e| test_rpc::Error::Service(e.to_string()))?;
 
+    restart_app().await?;
+    Ok(())
+}
+
+/// Restart the Mullvad VPN application.
+///
+/// This function waits for the app to successfully start again.
+#[cfg(target_os = "linux")]
+pub async fn restart_app() -> Result<(), test_rpc::Error> {
     tokio::process::Command::new("systemctl")
         .args(["restart", "mullvad-daemon"])
         .status()
         .await
         .map_err(|e| test_rpc::Error::Service(e.to_string()))?;
-
     wait_for_service_state(ServiceState::Running).await?;
     Ok(())
 }
 
+/// Stop the Mullvad VPN application.
+///
+/// This function waits for the app to successfully shut down.
+#[cfg(target_os = "linux")]
+pub async fn stop_app() -> Result<(), test_rpc::Error> {
+    set_mullvad_daemon_service_state(false).await
+}
+
+/// Start the Mullvad VPN application.
+///
+/// This function waits for the app to successfully start again.
+#[cfg(target_os = "linux")]
+pub async fn start_app() -> Result<(), test_rpc::Error> {
+    set_mullvad_daemon_service_state(true).await
+}
+
+/// Restart the Mullvad VPN application.
+///
+/// This function waits for the app to successfully start again.
+#[cfg(target_os = "windows")]
+pub async fn restart_app() -> Result<(), test_rpc::Error> {
+    stop_app().await?;
+    start_app().await?;
+    Ok(())
+}
+
+/// Stop the Mullvad VPN application.
+///
+/// This function waits for the app to successfully shut down.
+#[cfg(target_os = "windows")]
+pub async fn stop_app() -> Result<(), test_rpc::Error> {
+    let _ = tokio::process::Command::new("net")
+        .args(["stop", "mullvadvpn"])
+        .status()
+        .await
+        .map_err(|e| test_rpc::Error::Service(e.to_string()))?;
+    Ok(())
+}
+
+/// Start the Mullvad VPN application.
+///
+/// This function waits for the app to successfully start again.
+#[cfg(target_os = "windows")]
+pub async fn start_app() -> Result<(), test_rpc::Error> {
+    let _ = tokio::process::Command::new("net")
+        .args(["start", "mullvadvpn"])
+        .status()
+        .await
+        .map_err(|e| test_rpc::Error::Service(e.to_string()))?;
+    Ok(())
+}
+
+/// Restart the Mullvad VPN application.
+///
+/// This function waits for the app to successfully start again.
+#[cfg(target_os = "macos")]
+pub async fn restart_app() -> Result<(), test_rpc::Error> {
+    stop_app().await?;
+    start_app().await?;
+    Ok(())
+}
+
+/// Stop the Mullvad VPN application.
+///
+/// This function waits for the app to successfully shut down.
+#[cfg(target_os = "macos")]
+pub async fn stop_app() -> Result<(), test_rpc::Error> {
+    set_mullvad_daemon_service_state(false).await
+}
+
+/// Start the Mullvad VPN application.
+///
+/// This function waits for the app to successfully start again.
+#[cfg(target_os = "macos")]
+pub async fn start_app() -> Result<(), test_rpc::Error> {
+    set_mullvad_daemon_service_state(true).await
+}
+
 #[cfg(target_os = "windows")]
 pub async fn set_daemon_log_level(verbosity_level: Verbosity) -> Result<(), test_rpc::Error> {
     log::debug!("Setting log level");
@@ -226,6 +312,7 @@ pub async fn set_daemon_log_level(verbosity_level: Verbosity) -> Result<(), test
         .map_err(|e| test_rpc::Error::Service(e.to_string()))?;
 
     // Stop the service
+    // TODO: Extract to separate function.
     service
         .stop()
         .map_err(|e| test_rpc::Error::Service(e.to_string()))?;
@@ -266,6 +353,7 @@ pub async fn set_daemon_log_level(verbosity_level: Verbosity) -> Result<(), test
         .map_err(|e| test_rpc::Error::Service(e.to_string()))?;
 
     // Start the service
+    // TODO: Extract to separate function.
     service
         .start::<String>(&[])
         .map_err(|e| test_rpc::Error::Service(e.to_string()))?;
@@ -341,17 +429,8 @@ pub async fn set_daemon_environment(env: HashMap<String, String>) -> Result<(),
     }
 
     // Restart service
-    tokio::process::Command::new("net")
-        .args(["stop", "mullvadvpn"])
-        .status()
-        .await
-        .map_err(|e| test_rpc::Error::Service(e.to_string()))?;
-
-    tokio::process::Command::new("net")
-        .args(["start", "mullvadvpn"])
-        .status()
-        .await
-        .map_err(|e| test_rpc::Error::Service(e.to_string()))?;
+    stop_app().await?;
+    start_app().await?;
 
     Ok(())
 }