3 files changed, 112 insertions, 9 deletions

diff --git a/mullvad-daemon/src/lib.rs b/mullvad-daemon/src/lib.rs
index 6b3c061398..b3aa513f6e 100644
--- a/mullvad-daemon/src/lib.rs
+++ b/mullvad-daemon/src/lib.rs
@@ -18,6 +18,7 @@ pub mod logging;
 mod management_interface;
 mod relays;
 mod rpc_uniqueness_check;
+mod settings;
 pub mod version;
 
 pub use crate::management_interface::ManagementCommand;
@@ -40,10 +41,10 @@ use mullvad_types::{
         RelayConstraintsUpdate, RelaySettings, RelaySettingsUpdate, TunnelConstraints,
     },
     relay_list::{Relay, RelayList},
-    settings::{self, Settings},
     states::TargetState,
     version::{AppVersion, AppVersionInfo},
 };
+use settings::Settings;
 use std::{io, mem, path::PathBuf, sync::mpsc, thread, time::Duration};
 use talpid_core::{
     mpsc::IntoSender,
@@ -75,9 +76,6 @@ pub enum Error {
     #[error(display = "Unable to create am.i.mullvad client")]
     InitHttpsClient(#[error(cause)] mullvad_rpc::rest::Error),
 
-    #[error(display = "Unable to load settings")]
-    LoadSettings(#[error(cause)] settings::Error),
-
     #[error(display = "Unable to load account history with wireguard key cache")]
     LoadAccountHistory(#[error(cause)] account_history::Error),
 
@@ -340,7 +338,9 @@ where
             &resource_dir,
             &cache_dir,
         );
-        let settings = Settings::load().map_err(Error::LoadSettings)?;
+
+        let settings = settings::load();
+
         let account_history =
             account_history::AccountHistory::new(&cache_dir).map_err(Error::LoadAccountHistory)?;
 
diff --git a/mullvad-daemon/src/settings.rs b/mullvad-daemon/src/settings.rs
new file mode 100644
index 0000000000..6aeee0223c
--- /dev/null
+++ b/mullvad-daemon/src/settings.rs
@@ -0,0 +1,107 @@
+#[cfg(windows)]
+use log::{error, warn};
+
+use log::info;
+
+#[cfg(windows)]
+use mullvad_types::settings::Error as SettingsError;
+
+pub use mullvad_types::settings::*;
+
+#[cfg(windows)]
+use std::io::ErrorKind;
+
+#[cfg(windows)]
+use std::{
+    os::raw::{c_char, c_void},
+    ptr,
+};
+
+pub fn load() -> Settings {
+    match Settings::load() {
+        Ok(settings) => settings,
+        #[cfg(windows)]
+        Err(SettingsError::ReadError(ref _path, ref e)) if e.kind() == ErrorKind::NotFound => {
+            info!(
+                "No settings file found. Attempting migration from Windows Update backup location"
+            );
+            if migrate_after_windows_update() {
+                match Settings::load() {
+                    Ok(settings) => {
+                        info!("Successfully loaded migrated settings");
+                        settings
+                    }
+                    Err(_) => {
+                        warn!("Failed to load migrated settings, using defaults");
+                        Settings::default()
+                    }
+                }
+            } else {
+                info!("Failed to migrate settings, using defaults");
+                Settings::default()
+            }
+        }
+        Err(_) => {
+            info!("Failed to load settings, using defaults");
+            Settings::default()
+        }
+    }
+}
+
+#[cfg(windows)]
+fn migrate_after_windows_update() -> bool {
+    match unsafe { ffi::WinUtil_MigrateAfterWindowsUpdate(Some(log_sink), ptr::null_mut()) } {
+        ffi::WinUtilMigrationStatus::Success => {
+            info!("Migration completed successfully");
+            true
+        }
+        ffi::WinUtilMigrationStatus::Aborted => {
+            error!("Migration was aborted to avoid overwriting current settings");
+            false
+        }
+        ffi::WinUtilMigrationStatus::NothingToMigrate => {
+            info!("Could not migrate settings - no backup present");
+            false
+        }
+        ffi::WinUtilMigrationStatus::Failed | _ => {
+            error!("Migration failed");
+            false
+        }
+    }
+}
+
+#[cfg(windows)]
+extern "system" fn log_sink(msg: *const c_char, _ctx: *mut c_void) {
+    use std::ffi::CStr;
+    if msg.is_null() {
+        error!("Log message from FFI boundary is NULL");
+    } else {
+        error!("{}", unsafe { CStr::from_ptr(msg).to_string_lossy() });
+    }
+}
+
+#[cfg(windows)]
+mod ffi {
+    use super::*;
+
+    #[allow(dead_code)]
+    #[repr(u32)]
+    pub enum WinUtilMigrationStatus {
+        Success = 0,
+        Aborted = 1,
+        NothingToMigrate = 2,
+        Failed = 3,
+        Dummy = 9001,
+    }
+
+    type ErrorSink = extern "system" fn(msg: *const c_char, ctx: *mut c_void);
+
+    #[allow(non_snake_case)]
+    extern "system" {
+        #[link_name = "WinUtil_MigrateAfterWindowsUpdate"]
+        pub fn WinUtil_MigrateAfterWindowsUpdate(
+            sink: Option<ErrorSink>,
+            sink_context: *mut c_void,
+        ) -> WinUtilMigrationStatus;
+    }
+}
diff --git a/mullvad-types/src/settings.rs b/mullvad-types/src/settings.rs
index 10e5b03298..41f280c973 100644
--- a/mullvad-types/src/settings.rs
+++ b/mullvad-types/src/settings.rs
@@ -84,10 +84,6 @@ impl Settings {
                 info!("Loading settings from {}", path.display());
                 Self::read_settings(&mut io::BufReader::new(file))
             }
-            Err(ref e) if e.kind() == io::ErrorKind::NotFound => {
-                info!("No settings file at {}, using defaults", path.display());
-                Ok(Settings::default())
-            }
             Err(e) => Err(Error::ReadError(path.display().to_string(), e)),
         }
     }