recovery: Add wipe system partition option

Change-Id: Id606cef249a7464037443de6265055803c290d82

device.cpp

@@ -68,6 +68,7 @@ static const char* ADVANCED_MENU_NAMES[] = {
 #endif
 #ifndef RELEASE_BUILD
     "Mount /system",
+    "Wipe system partition",
 #endif
     "View recovery logs",
     "Run graphics test",
@@ -83,6 +84,7 @@ static const menu_entry ADVANCED_MENU_ENTRIES[] = {
 #endif
 #ifndef RELEASE_BUILD
     { ACTION_INVOKE, { .action = Device::MOUNT_SYSTEM } },
+    { ACTION_INVOKE, { .action = Device::WIPE_SYSTEM } },
 #endif
     { ACTION_INVOKE, { .action = Device::VIEW_RECOVERY_LOGS } },
     { ACTION_INVOKE, { .action = Device::RUN_GRAPHICS_TEST } },

device.h

@@ -75,6 +75,7 @@ class Device : public VoldWatcher {
         VIEW_RECOVERY_LOGS,
         MOUNT_SYSTEM,
         RUN_GRAPHICS_TEST,
+        WIPE_SYSTEM,
     };
 
     // Return the list of menu items (an array of strings,

recovery.cpp

@@ -1023,6 +1023,20 @@ static bool wipe_cache(bool should_confirm, Device* device) {
     return success;
 }
 
+// Return true on success.
+static bool wipe_system(Device* device) {
+    if (!yes_no(device, "Wipe system?", "  THIS CAN NOT BE UNDONE!")) {
+        return false;
+    }
+
+    modified_flash = true;
+
+    ui->Print("\n-- Wiping system...\n");
+    bool success = erase_volume("/system");
+    ui->Print("System wipe %s.\n", success ? "complete" : "failed");
+    return success;
+}
+
 static void choose_recovery_file(Device* device) {
     if (!has_cache) {
         ui->Print("No /cache partition found.\n");
@@ -1382,6 +1396,10 @@ prompt_and_wait(Device* device, int status) {
                         }
                     }
                     break;
+
+                case Device::WIPE_SYSTEM:
+                    wipe_system(device);
+                    break;
             }
             if (status == Device::kRefresh) {
                 status = 0;