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Refactor RunCommandService
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- The `FileUtils` and `PluginUtils` have been added to provide utility functions.
- The executable and working directory validation has been added to check for existence and missing permissions.
- The `expandPath()` function is removed from `RunCommandService`.
- Working directory will automatically be created if under `TermuxConstants.TERMUX_FILES_DIR_PATH` if missing.
- Better logging has been added. This will later be used to notify the user in foreground.
- Javadocs have been updated.
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@agnostic-apollo
agnostic-apollo committed Mar 19, 2021
1 parent ec7568d commit b4995ef
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170 changes: 116 additions & 54 deletions app/src/main/java/com/termux/app/RunCommandService.java
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Original file line number Diff line number Diff line change
Expand Up @@ -10,27 +10,79 @@
import android.os.Binder;
import android.os.Build;
import android.os.IBinder;
import android.util.Log;

import com.termux.R;
import com.termux.app.TermuxConstants.TERMUX_APP.RUN_COMMAND_SERVICE;
import com.termux.app.TermuxConstants.TERMUX_APP.TERMUX_SERVICE;
import com.termux.app.settings.properties.SharedProperties;
import com.termux.app.settings.properties.TermuxPropertyConstants;
import com.termux.app.utils.FileUtils;
import com.termux.app.utils.Logger;
import com.termux.app.utils.PluginUtils;

import java.util.Arrays;
import java.util.HashMap;

/**
* Third-party apps that are not part of termux world can run commands in termux context by either
* sending an intent to RunCommandService or becoming a plugin host for the termux-tasker plugin
* client.
*
* For the {@link RUN_COMMAND_SERVICE#ACTION_RUN_COMMAND} intent to work, there are 2 main requirements:
* For the {@link RUN_COMMAND_SERVICE#ACTION_RUN_COMMAND} intent to work, here are the requirements:
*
* 1. The `allow-external-apps` property must be set to "true" in ~/.termux/termux.properties in
* termux app, regardless of if the executable path is inside or outside the `~/.termux/tasker/`
* directory.
* 2. The intent sender/third-party app must request the `com.termux.permission.RUN_COMMAND`
* 1. `com.termux.permission.RUN_COMMAND` permission (Mandatory)
* The Intent sender/third-party app must request the `com.termux.permission.RUN_COMMAND`
* permission in its `AndroidManifest.xml` and it should be granted by user to the app through the
* app's App Info permissions page in android settings, likely under Additional Permissions.
* app's `App Info` `Permissions` page in Android Settings, likely under `Additional Permissions`.
* This is a security measure to prevent any other apps from running commands in `Termux` context
* which do not have the required permission granted to them.
*
* For `Tasker` you can grant it with:
* `Android Settings` -> `Apps` -> `Tasker` -> `Permissions` -> `Additional permissions` ->
* `Run commands in Termux environment`.
*
* 2. `allow-external-apps` property (Mandatory)
* The `allow-external-apps` property must be set to "true" in `~/.termux/termux.properties` in
* Termux app, regardless of if the executable path is inside or outside the `~/.termux/tasker/`
* directory. Check https://github.com/termux/termux-tasker#allow-external-apps-property-optional
* for more info.
*
* 3. `Draw Over Apps` permission (Optional)
* For android `>= 10` there are new
* [restrictions](https://developer.android.com/guide/components/activities/background-starts)
* that prevent activities from starting from the background. This prevents the background
* {@link TermuxService} from starting a terminal session in the foreground and running the
* commands until the user manually clicks `Termux` notification in the status bar dropdown
* notifications list. This only affects commands that are to be executed in a terminal
* session and not the background ones. `Termux` version `>= 0.100`
* requests the `Draw Over Apps` permission so that users can bypass this restriction so
* that commands can automatically start running without user intervention.
* You can grant `Termux` the `Draw Over Apps` permission from its `App Info` activity:
* `Android Settings` -> `Apps` -> `Termux` -> `Advanced` -> `Draw over other apps`.
*
* 4. `Storage` permission (Optional)
* Termux app must be granted `Storage` permission if the executable is accessing or working
* directory is set to path in external shared storage. The common paths which usually refer to
* it are `~/storage`, `/sdcard`, `/storage/emulated/0` etc.
* You can grant `Termux` the `Storage` permission from its `App Info` activity:
* For Android version < 11:
* `Android Settings` -> `Apps` -> `Termux` -> `Permissions` -> `Storage`.
* For Android version >= 11
* `Android Settings` -> `Apps` -> `Termux` -> `Permissions` -> `Files and media` ->
* `Allowed management of all files`.
* NOTE: For Android version >= 11, sometimes you will get `Permission Denied` errors for
* external shared storage even when you have granted `Files and media` permission. To solve
* this, Deny the permission and then Allow it again and restart Termux.
* Also check https://wiki.termux.com/wiki/Termux-setup-storage
*
* 5. Battery Optimizations (May be mandatory depending on device)
* Some devices kill apps aggressively or prevent apps from starting from background.
* If Termux is running into such problems, then exempt it from such restrictions.
* The user may also disable battery optimizations for Termux to reduce the chances of Termux
* being killed by Android even further due to violation of not being able to call
* `startForeground()` within ~5s of service start in android >= 8.
* Check https://dontkillmyapp.com/ for device specfic info to opt-out of battery optimiations.
*
* You may also want to check https://github.com/termux/termux-tasker
*
*
*
Expand All @@ -55,21 +107,6 @@
* The "$PREFIX/" will expand to {@link TermuxConstants#TERMUX_PREFIX_DIR_PATH} and
* "~/" will expand to {@link TermuxConstants#TERMUX_HOME_DIR_PATH}, followed by a forward slash "/".
*
*
* To automatically bring termux session to foreground and start termux commands that were started
* with background mode "false" in android >= 10 without user having to click the notification
* manually requires termux to be granted draw over apps permission due to new restrictions
* of starting activities from the background, this also applies to Termux:Tasker plugin.
*
* Check https://github.com/termux/termux-tasker for more details on allow-external-apps and draw
* over apps and other limitations.
*
*
* To reduce the chance of termux being killed by android even further due to violation of not
* being able to call startForeground() within ~5s of service start in android >= 8, the user
* may disable battery optimizations for termux.
*
*
* If your third-party app is targeting sdk 30 (android 11), then it needs to add `com.termux`
* package to the `queries` element or request `QUERY_ALL_PACKAGES` permission in its
* `AndroidManifest.xml`. Otherwise it will get `PackageSetting{...... com.termux/......} BLOCKED`
Expand Down Expand Up @@ -129,44 +166,80 @@ public int onStartCommand(Intent intent, int flags, int startId) {
// Run again in case service is already started and onCreate() is not called
runStartForeground();

String errmsg;

// If invalid action passed, then just return
if (!RUN_COMMAND_SERVICE.ACTION_RUN_COMMAND.equals(intent.getAction())) {
Logger.logError(LOG_TAG, "Invalid intent action to RunCommandService: \"" + intent.getAction() + "\"");
errmsg = this.getString(R.string.run_command_service_invalid_action, intent.getAction());
Logger.logError(LOG_TAG, errmsg);
return Service.START_NOT_STICKY;
}

// If allow-external-apps property is not set to "true"
if (!SharedProperties.isPropertyValueTrue(this, TermuxPropertyConstants.getTermuxPropertiesFile(), TermuxConstants.PROP_ALLOW_EXTERNAL_APPS)) {
Logger.logError(LOG_TAG, "RunCommandService requires allow-external-apps property to be set to \"true\" in \"" + TermuxConstants.TERMUX_PROPERTIES_PRIMARY_FILE_PATH + "\" file");
// If "allow-external-apps" property to not set to "true", then just return
errmsg = PluginUtils.checkIfRunCommandServiceAllowExternalAppsPolicyIsViolated(this);
if (errmsg != null) {
Logger.logError(LOG_TAG, errmsg);
return Service.START_NOT_STICKY;
}



String commandPath = intent.getStringExtra(RUN_COMMAND_SERVICE.EXTRA_COMMAND_PATH);
// If invalid commandPath passed, then just return
if (commandPath == null || commandPath.isEmpty()) {
Logger.logError(LOG_TAG, "Invalid coommand path to RunCommandService: \"" + commandPath + "\"");
String executable = intent.getStringExtra(RUN_COMMAND_SERVICE.EXTRA_COMMAND_PATH);
String[] arguments = intent.getStringArrayExtra(RUN_COMMAND_SERVICE.EXTRA_ARGUMENTS);
boolean inBackground = intent.getBooleanExtra(RUN_COMMAND_SERVICE.EXTRA_BACKGROUND, false);
String workingDirectory = intent.getStringExtra(RUN_COMMAND_SERVICE.EXTRA_WORKDIR);
String sessionAction = intent.getStringExtra(RUN_COMMAND_SERVICE.EXTRA_SESSION_ACTION);

// Get canonical path of executable
executable = FileUtils.getCanonicalPath(executable, null, true);

// If executable is not a regular file, or is not readable or executable, then just return
// Setting of missing read and execute permissions is not done
errmsg = FileUtils.validateRegularFileExistenceAndPermissions(this, executable,
null, PluginUtils.PLUGIN_EXECUTABLE_FILE_PERMISSIONS,
false, false);
if (errmsg != null) {
errmsg += "\n" + this.getString(R.string.executable_absolute_path, executable);
Logger.logError(LOG_TAG, errmsg);
return Service.START_NOT_STICKY;
}

Uri programUri = new Uri.Builder().scheme(TERMUX_SERVICE.URI_SCHEME_SERVICE_EXECUTE).path(getExpandedTermuxPath(commandPath)).build();
// If workingDirectory is not null or empty
if (workingDirectory != null && !workingDirectory.isEmpty()) {
// Get canonical path of workingDirectory
workingDirectory = FileUtils.getCanonicalPath(workingDirectory, null, true);

// If workingDirectory is not a directory, or is not readable or writable, then just return
// Creation of missing directory and setting of read, write and execute permissions are only done if workingDirectory is
// under {@link TermuxConstants#TERMUX_FILES_DIR_PATH}
// We try to set execute permissions, but ignore if they are missing, since only read and write permissions are required
// for working directories.
errmsg = FileUtils.validateDirectoryExistenceAndPermissions(this, workingDirectory,
TermuxConstants.TERMUX_FILES_DIR_PATH, PluginUtils.PLUGIN_WORKING_DIRECTORY_PERMISSIONS,
true, true, false,
true);
if (errmsg != null) {
errmsg += "\n" + this.getString(R.string.working_directory_absolute_path, workingDirectory);
Logger.logError(LOG_TAG, errmsg);
return Service.START_NOT_STICKY;
}
}

PluginUtils.dumpExecutionIntentToLog(Log.VERBOSE, LOG_TAG, "RUN_COMMAND Intent", executable, Arrays.asList(arguments), workingDirectory, inBackground, new HashMap<String, Object>() {{
put("sessionAction", sessionAction);
}});

Uri executableUri = new Uri.Builder().scheme(TERMUX_SERVICE.URI_SCHEME_SERVICE_EXECUTE).path(FileUtils.getExpandedTermuxPath(executable)).build();

Intent execIntent = new Intent(TERMUX_SERVICE.ACTION_SERVICE_EXECUTE, programUri);
// Create execution intent with the action TERMUX_SERVICE#ACTION_SERVICE_EXECUTE to be sent to the TERMUX_SERVICE
Intent execIntent = new Intent(TERMUX_SERVICE.ACTION_SERVICE_EXECUTE, executableUri);
execIntent.setClass(this, TermuxService.class);
execIntent.putExtra(TERMUX_SERVICE.EXTRA_ARGUMENTS, intent.getStringArrayExtra(RUN_COMMAND_SERVICE.EXTRA_ARGUMENTS));
execIntent.putExtra(TERMUX_SERVICE.EXTRA_BACKGROUND, intent.getBooleanExtra(RUN_COMMAND_SERVICE.EXTRA_BACKGROUND, false));
execIntent.putExtra(TERMUX_SERVICE.EXTRA_SESSION_ACTION, intent.getStringExtra(RUN_COMMAND_SERVICE.EXTRA_SESSION_ACTION));

String workingDirectory = intent.getStringExtra(RUN_COMMAND_SERVICE.EXTRA_WORKDIR);
if (workingDirectory != null && !workingDirectory.isEmpty()) {
execIntent.putExtra(TERMUX_SERVICE.EXTRA_WORKDIR, getExpandedTermuxPath(workingDirectory));
}

execIntent.putExtra(TERMUX_SERVICE.EXTRA_ARGUMENTS, arguments);
execIntent.putExtra(TERMUX_SERVICE.EXTRA_BACKGROUND, inBackground);
if (workingDirectory != null && !workingDirectory.isEmpty()) execIntent.putExtra(TERMUX_SERVICE.EXTRA_WORKDIR, workingDirectory);
execIntent.putExtra(TERMUX_SERVICE.EXTRA_SESSION_ACTION, sessionAction);


// Start TERMUX_SERVICE and pass it execution intent
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
this.startForegroundService(execIntent);
} else {
Expand Down Expand Up @@ -223,15 +296,4 @@ private void setupNotificationChannel() {
manager.createNotificationChannel(channel);
}

/** Replace "$PREFIX/" or "~/" prefix with termux absolute paths */
public static String getExpandedTermuxPath(String path) {
if(path != null && !path.isEmpty()) {
path = path.replaceAll("^\\$PREFIX$", TermuxConstants.TERMUX_PREFIX_DIR_PATH);
path = path.replaceAll("^\\$PREFIX/", TermuxConstants.TERMUX_PREFIX_DIR_PATH + "/");
path = path.replaceAll("^~/$", TermuxConstants.TERMUX_HOME_DIR_PATH);
path = path.replaceAll("^~/", TermuxConstants.TERMUX_HOME_DIR_PATH + "/");
}

return path;
}
}
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