First pass of save

src/dusklinux/save/savedevicelinux.c

@@ -0,0 +1,51 @@
+/**
+ * Copyright (c) 2026 Dominic Masters
+ * 
+ * This software is released under the MIT License.
+ * https://opensource.org/licenses/MIT
+ */
+
+#include "save/savedevice.h"
+#include "save/savedevicelinux.h"
+#include "assert/assert.h"
+#include "util/mkdirp.h"
+
+errorret_t saveDeviceLinuxInit(savedevice_t *device) {
+  assertNotNull(device, "device cannot be null");
+  
+  device->state = SAVE_DEVICE_STATE_UNKNOWN;
+
+  errorOk();
+}
+
+errorret_t saveDeviceLinuxUpdate(savedevice_t *device) {
+  assertNotNull(device, "device cannot be null");
+  assertIsMainThread("Invalid thread");
+  errorOk();
+}
+
+void saveDeviceLinuxCheckAvailability(savedevice_t *device) {
+  assertNotNull(device, "device cannot be null");
+  assertIsMainThread("Invalid thread");
+  assertTrue(
+    device->state == SAVE_DEVICE_STATE_CHECKING_AVAILABILITY,
+    "Device state incorrect?"
+  );
+  
+  // Mkdirp the save directory.
+  int mkdirpResult = mkdirp(SAVE_DEVICE_LINUX_DIRECTORY, 0700);
+  if(mkdirpResult != 0) {
+    device->state = SAVE_DEVICE_STATE_UNAVAILABLE;
+    device->reasonKey = "save.linux.mkdirp_failed";
+    return saveDeviceFireCallback(device);
+  }
+
+  // The save device is available.
+  device->state = SAVE_DEVICE_STATE_AVAILABLE;
+  device->reasonKey = NULL;
+  saveDeviceFireCallback(device);
+}
+
+errorret_t saveDeviceLinuxDispose(savedevice_t *device) {
+  errorOk();
+}