feat: add system user

Author: KernelDeimos

src/backend/src/services/database/SqliteDatabaseAccessService.js

@@ -42,7 +42,7 @@ class SqliteDatabaseAccessService extends BaseDatabaseAccessService {
         this.db = new Database(this.config.path);
 
         // Database upgrade logic
-        const TARGET_VERSION = 22;
+        const TARGET_VERSION = 23;
 
         if ( do_setup ) {
             this.log.noticeme(`SETUP: creating database at ${this.config.path}`);
@@ -71,6 +71,7 @@ class SqliteDatabaseAccessService extends BaseDatabaseAccessService {
                 '0022_dev-center-max.sql',
                 '0023_fix-kv.sql',
                 '0024_default-groups.sql',
+                '0025_system-user.dbmig.js'
             ].map(p => path_.join(__dirname, 'sqlite_setup', p));
             const fs = require('fs');
             for ( const filename of sql_files ) {
@@ -175,6 +176,10 @@ class SqliteDatabaseAccessService extends BaseDatabaseAccessService {
             upgrade_files.push('0024_default-groups.sql');
         }
 
+        if ( user_version <= 22 ) {
+            upgrade_files.push('0025_system-user.dbmig.js');
+        }
+
         if ( upgrade_files.length > 0 ) {
             this.log.noticeme(`Database out of date: ${this.config.path}`);
             this.log.noticeme(`UPGRADING DATABASE: ${user_version} -> ${TARGET_VERSION}`);
@@ -188,7 +193,20 @@ class SqliteDatabaseAccessService extends BaseDatabaseAccessService {
                 const basename = path_.basename(filename);
                 this.log.noticeme(`applying ${basename}`);
                 const contents = fs.readFileSync(filename, 'utf8');
-                this.db.exec(contents);
+                switch ( path_.extname(filename) ) {
+                    case '.sql':
+                        this.db.exec(contents);
+                        break;
+                    case '.js':
+                        await this.run_js_migration_({
+                            filename, contents,
+                        });
+                        break;
+                    default:
+                        throw new Error(
+                            `unrecognized migration type: ${filename}`
+                        );
+                }
             }
 
             // Update version number
@@ -273,6 +291,17 @@ class SqliteDatabaseAccessService extends BaseDatabaseAccessService {
             return p;
         });
     }
+    
+    async run_js_migration_ ({ filename, contents }) {
+        contents = `(async () => {${contents}})()`;
+        const vm = require('vm');
+        const context = vm.createContext({
+            read: this.read.bind(this),
+            write: this.write.bind(this),
+            log: this.log,
+        });
+        await vm.runInContext(contents, context);
+    }
 
     _register_commands (commands) {
         commands.registerCommands('sqlite', [

src/backend/src/services/database/sqlite_setup/0025_system-user.dbmig.js

@@ -0,0 +1,63 @@
+/*
+Add a user called `system`.
+
+If a user called `system` already exists, first rename the existing
+user to the first username in this sequence:
+    system_, system_0, system_1, system_2, ...
+*/
+
+let existing_user;
+
+;[existing_user] = await read(
+    "SELECT username FROM `user` WHERE username='system'",
+);
+
+if ( existing_user ) {
+    let replace_num = 0;
+    let replace_name = 'system_';
+
+    for (;;) {
+        ;[existing_user] = await read(
+            'SELECT username FROM `user` WHERE username=?',
+            [replace_name]
+        );
+        if ( ! existing_user ) break;
+        replace_name = 'system_' + (replace_num++);
+    }
+    
+    log.noticeme('updating existing user called system', {
+        replace_num,
+        replace_name,
+    });
+
+    await write(
+        `UPDATE \`user\` SET username=? WHERE username='system' LIMIT 1`,
+        [replace_name]
+    );
+}
+
+const { insertId: system_user_id } = await write(
+    'INSERT INTO `user` (`uuid`, `username`) VALUES (?, ?)',
+    [
+        '5d4adce0-a381-4982-9c02-6e2540026238',
+        'system',
+    ]
+);
+
+const [{id: system_group_id}] = await read(
+    'SELECT id FROM `group` WHERE uid=?',
+    ['26bfb1fb-421f-45bc-9aa4-d81ea569e7a5']
+);
+
+const [{id: admin_group_id}] = await read(
+    'SELECT id FROM `group` WHERE uid=?',
+    ['ca342a5e-b13d-4dee-9048-58b11a57cc55']
+);
+
+// admin group has unlimited access to all drivers
+await write(
+    'INSERT INTO `user_to_group_permissions` ' +
+    '(`user_id`, `group_id`, `permission`, `extra`) ' +
+    'VALUES (?, ?, ?, ?)',
+    [system_user_id, admin_group_id, 'driver', '{}']
+);