feat: Allow to enable the access to the system shell via server features

lib/commands/execute.js

@@ -0,0 +1,102 @@
+import { exec } from 'teen_process';
+import _ from 'lodash';
+import log from '../logger';
+import { fs, tempDir } from 'appium-support';
+import path from 'path';
+
+const SYSTEM_SHELL_FEATURE = 'system_shell';
+
+const commands = {};
+
+/**
+ * @typedef {Object} ExecOptions
+ * @property {?string} interpreter - Full path to the command line interpreter binary.
+ * The current interpreter (`$SHELL`) or `/bin/bash` is used by default
+ * @property {?boolean} throwOnFail [false] - Whether to throw an exception if
+ * the given script has returned non-zero exit code
+ * @property {?number} timeout [20000] - The default timeout for the script execution.
+ * @property {?Object} env [process.env] - Additional environment variables for
+ * the shell script
+ */
+
+/**
+ * @typedef {Object} ExecResult
+ * @property {string} stdout - Script stdout
+ * @property {string} stderr - Script stderr
+ * @property {number} code - Script return code. It will never be other
+ * than zero if `throwOnFail` option is set to `true`
+ */
+
+/**
+ * Executes the given shell script if the `system_shell`
+ * server feature is enabled. The command blocks until
+ * the script finishes its execution or its timeout expires.
+ *
+ * @param {!string} script - The actual shell script to execute.
+ * This should be a valid script snippet.
+ * @param {?ExecOptions} args
+ * @return {ExecResult} - The result of the script execution
+ * @throws {Error} If there was a problem during command execution
+ */
+commands.execute = async function execute (script, args) {
+  this.ensureFeatureEnabled(SYSTEM_SHELL_FEATURE);
+
+  if (!_.isEmpty(script)) {
+    log.errorAndThrow(`The 'script' argument cannot be empty`);
+  }
+
+  let opts = {};
+  if (_.isArray(args) && _.isPlainObject(args[0])) {
+    opts = args[0];
+  } else if (_.isPlainObject(args)) {
+    opts = args;
+  }
+  const {
+    interpreter = process.env.SHELL || '/bin/bash',
+    throwOnFail = false,
+    timeout,
+    env,
+  } = opts;
+
+  const tmpRoot = await tempDir.openDir();
+  try {
+    const tmpScriptPath = path.resolve(tmpRoot, 'appium.sh');
+    await fs.writeFile(tmpScriptPath, script, 'utf8');
+    log.debug(`Executing script using '${interpreter}' shell interpreter:`);
+    const execOpts = {};
+    if (_.isInteger(timeout)) {
+      log.debug(`- Timeout: ${timeout}ms`);
+      execOpts.timeout = timeout;
+    }
+    if (!_.isEmpty(env)) {
+      log.debug(`- Environment: ${JSON.stringify(env)}`);
+      execOpts.env = Object.assign({}, process.env, env);
+    }
+    log.debug(script);
+    // TODO: Add some perf measurement here?
+    const {stdout, stderr} = await exec(interpreter, [tmpScriptPath], execOpts);
+    return {
+      stdout,
+      stderr,
+      code: 0,
+    };
+  } catch (e) {
+    if (_.has(e, 'code')) {
+      const {stdout, stderr, code} = e;
+      // Do not throw if the script return code is not zero
+      log.debug(`The script has returned non-zero exit code ${code}`);
+      if (stderr) {
+        log.debug(`Stderr: ${stderr}`);
+      }
+      if (!throwOnFail) {
+        return {stdout, stderr, code};
+      }
+    }
+    throw e;
+  } finally {
+    await fs.rimraf(tmpRoot);
+  }
+};
+
+export { commands };
+export default commands;

lib/commands/index.js

@@ -0,0 +1,11 @@
+import executeCmds from './execute';
+
+const commands = {};
+Object.assign(
+  commands,
+  executeCmds,
+  // add other command types here
+);
+
+export { commands };
+export default commands;

lib/driver.js

@@ -2,6 +2,8 @@ import { BaseDriver } from 'appium-base-driver';
 import { system } from 'appium-support';
 import { AppiumForMac, DEFAULT_A4M_HOST} from './appium-for-mac';
 import logger from './logger';
+import commands from './commands/index';
+import _ from 'lodash';
 
 /* eslint-disable no-useless-escape */
 const NO_PROXY_LIST = [
@@ -14,6 +16,10 @@ class MacDriver extends BaseDriver {
     super(opts, shouldValidateCaps);
     this.jwpProxyActive = false;
     this.opts.address = opts.address || DEFAULT_A4M_HOST;
+
+    for (let [cmd, fn] of _.toPairs(commands)) {
+      MacDriver.prototype[cmd] = fn;
+    }
   }
 
   async createSession (...args) {
@@ -57,13 +63,6 @@ class MacDriver extends BaseDriver {
     await super.deleteSession();
   }
 
-  async execute (script, args) {
-    if (!this.relaxedSecurityEnabled) {
-      logger.errorAndThrow(`Appium server must have relaxed security flag set in order to run any shell commands`);
-    }
-    return await this.a4mDriver.sendCommand(`/session/${this.sessionId}/execute`, 'POST', {script, args});
-  }
-
   proxyActive () {
     // we always have an active proxy to the AppiumForMac server
     return true;

package.json

@@ -33,11 +33,12 @@
   "dependencies": {
     "@babel/runtime": "^7.0.0",
     "appium-base-driver": "^5.0.0",
-    "appium-support": "^2.6.0",
+    "appium-support": "^2.36.0",
     "asyncbox": "^2.3.1",
     "bluebird": "^3.5.1",
+    "lodash": "^4.17.4",
     "source-map-support": "^0.5.5",
-    "teen_process": "^1.7.0",
+    "teen_process": "^1.15.0",
     "yargs": "^15.0.1"
   },
   "scripts": {