Add the TermuxSession class for linking a TerminalSession to an ExecutionCommand.

TermuxSession will maintain info for foreground Termux sessions. Each terminal session started by TermuxService will now be linked to a ExectionCommand that started it.

This also fixes bugs where newly created session in some cases were not being automatically selected and scrolled to, like when adding a named or failsafe session or those which were created for executable intents.

app/src/main/java/com/termux/app/TermuxActivity.java

@@ -214,7 +214,7 @@ public final class TermuxActivity extends Activity implements ServiceConnection
             // Get the session stored in shared preferences stored by {@link #onStop} if its valid,
             // otherwise get the last session currently running.
             mTermuxSessionClient.setCurrentSession(mTermuxSessionClient.getCurrentStoredSessionOrLast());
-            terminalSessionListNotifyUpdated();
+            termuxSessionListNotifyUpdated();
         }
 
         registerReceiver(mTermuxActivityBroadcastReceiever, new IntentFilter(TERMUX_ACTIVITY.ACTION_RELOAD_STYLE));
@@ -242,7 +242,7 @@ public final class TermuxActivity extends Activity implements ServiceConnection
 
         setTermuxSessionsListView();
 
-        if (mTermuxService.getSessions().isEmpty()) {
+        if (mTermuxService.isTermuxSessionsEmpty()) {
             if (mIsVisible) {
                 TermuxInstaller.setupIfNeeded(TermuxActivity.this, () -> {
                     if (mTermuxService == null) return; // Activity might have been destroyed.
@@ -395,9 +395,10 @@ public final class TermuxActivity extends Activity implements ServiceConnection
         View newSessionButton = findViewById(R.id.new_session_button);
         newSessionButton.setOnClickListener(v -> mTermuxSessionClient.addNewSession(false, null));
         newSessionButton.setOnLongClickListener(v -> {
-            DialogUtils.textInput(TermuxActivity.this, R.string.title_create_named_session, null, R.string.action_create_named_session_confirm,
-                text -> mTermuxSessionClient.addNewSession(false, text), R.string.action_new_session_failsafe, text -> mTermuxSessionClient.addNewSession(true, text)
-                , -1, null, null);
+            DialogUtils.textInput(TermuxActivity.this, R.string.title_create_named_session, null,
+                R.string.action_create_named_session_confirm, text -> mTermuxSessionClient.addNewSession(false, text),
+                R.string.action_new_session_failsafe, text -> mTermuxSessionClient.addNewSession(true, text),
+                -1, null, null);
             return true;
         });
     }
@@ -439,7 +440,7 @@ public final class TermuxActivity extends Activity implements ServiceConnection
 
     private void setTermuxSessionsListView() {
         ListView termuxSessionsListView = findViewById(R.id.terminal_sessions_list);
-        mTermuxSessionListViewController = new TermuxSessionsListViewController(this, mTermuxService.getSessions());
+        mTermuxSessionListViewController = new TermuxSessionsListViewController(this, mTermuxService.getTermuxSessions());
         termuxSessionsListView.setAdapter(mTermuxSessionListViewController);
         termuxSessionsListView.setOnItemClickListener(mTermuxSessionListViewController);
         termuxSessionsListView.setOnItemLongClickListener(mTermuxSessionListViewController);
@@ -468,6 +469,7 @@ public final class TermuxActivity extends Activity implements ServiceConnection
 
     /** Show a toast and dismiss the last one if still visible. */
     public void showToast(String text, boolean longDuration) {
+        if(text == null || text.isEmpty()) return;
         if (mLastToast != null) mLastToast.cancel();
         mLastToast = Toast.makeText(TermuxActivity.this, text, longDuration ? Toast.LENGTH_LONG : Toast.LENGTH_SHORT);
         mLastToast.setGravity(Gravity.TOP, 0, 0);
@@ -642,7 +644,7 @@ public final class TermuxActivity extends Activity implements ServiceConnection
         return (DrawerLayout) findViewById(R.id.drawer_layout);
     }
 
-    public void terminalSessionListNotifyUpdated() {
+    public void termuxSessionListNotifyUpdated() {
         mTermuxSessionListViewController.notifyDataSetChanged();
     }
 
@@ -683,6 +685,13 @@ public final class TermuxActivity extends Activity implements ServiceConnection
 
 
 
+    public static void updateTermuxActivityStyling(Context context) {
+        // Make sure that terminal styling is always applied.
+        Intent stylingIntent = new Intent(TERMUX_ACTIVITY.ACTION_RELOAD_STYLE);
+        stylingIntent.putExtra(TERMUX_ACTIVITY.EXTRA_RELOAD_STYLE, "styling");
+        context.sendBroadcast(stylingIntent);
+    }
+
     class TermuxActivityBroadcastReceiever extends BroadcastReceiver {
         @Override
         public void onReceive(Context context, Intent intent) {

app/src/main/java/com/termux/app/TermuxService.java

@@ -24,9 +24,11 @@ import com.termux.R;
 import com.termux.app.TermuxConstants.TERMUX_APP.TERMUX_ACTIVITY;
 import com.termux.app.TermuxConstants.TERMUX_APP.TERMUX_SERVICE;
 import com.termux.app.settings.preferences.TermuxAppSharedPreferences;
+import com.termux.app.terminal.TermuxSession;
 import com.termux.app.terminal.TermuxSessionClient;
 import com.termux.app.terminal.TermuxSessionClientBase;
 import com.termux.app.utils.Logger;
+import com.termux.app.utils.ShellUtils;
 import com.termux.app.utils.TextDataUtils;
 import com.termux.models.ExecutionCommand;
 import com.termux.models.ExecutionCommand.ExecutionState;
@@ -38,8 +40,10 @@ import java.io.File;
 import java.util.ArrayList;
 import java.util.List;
 
+import javax.annotation.Nullable;
+
 /**
- * A service holding a list of terminal sessions, {@link #mTerminalSessions}, showing a foreground notification while
+ * A service holding a list of termux sessions, {@link #mTermuxSessions}, showing a foreground notification while
  * running so that it is not terminated. The user interacts with the session through {@link TermuxActivity}, but this
  * service may outlive the activity when the user or the system disposes of the activity. In that case the user may
  * restart {@link TermuxActivity} later to yet again access the sessions.
@@ -67,12 +71,12 @@ public final class TermuxService extends Service {
     private final Handler mHandler = new Handler();
 
     /**
-     * The terminal sessions which this service manages.
+     * The termux sessions which this service manages.
      * Note that this list is observed by {@link TermuxActivity#mTermuxSessionListViewController},
      * so any changes must be made on the UI thread and followed by a call to
      * {@link ArrayAdapter#notifyDataSetChanged()} }.
      */
-    final List<TerminalSession> mTerminalSessions = new ArrayList<>();
+    final List<TermuxSession> mTermuxSessions = new ArrayList<>();
 
     /**
      * The background jobs which this service manages.
@@ -160,7 +164,7 @@ public final class TermuxService extends Service {
         }
 
         actionReleaseWakeLock(false);
-        finishAllTerminalSessions();
+        finishAllTermuxSessions();
         runStopForeground();
     }
 
@@ -205,7 +209,7 @@ public final class TermuxService extends Service {
     /** Process action to stop service. */
     private void actionStopService() {
         mWantsToStop = true;
-        finishAllTerminalSessions();
+        finishAllTermuxSessions();
         requestStopService();
     }
 
@@ -273,7 +277,8 @@ public final class TermuxService extends Service {
         Logger.logDebug(LOG_TAG, "WakeLocks released successfully");
     }
 
-    /** Process action to execute a shell command in a foreground session or in background. */
+    /** Process {@link TERMUX_SERVICE#ACTION_SERVICE_EXECUTE} intent to execute a shell command in
+     * a foreground termux session or in background. */
     private void actionServiceExecute(Intent intent) {
         if (intent == null){
             Logger.logError(LOG_TAG, "Ignoring null intent to actionServiceExecute");
@@ -303,15 +308,18 @@ public final class TermuxService extends Service {
         if (executionCommand.inBackground) {
             executeBackgroundCommand(executionCommand);
         } else {
-            executeForegroundCommand(executionCommand);
+            executeTermuxSessionCommand(executionCommand);
         }
     }
 
     /** Execute a shell command in background with {@link BackgroundJob}. */
     private void executeBackgroundCommand(ExecutionCommand executionCommand) {
+        if (executionCommand == null) return;
+        
         Logger.logDebug(LOG_TAG, "Starting background command");
 
-        Logger.logDebug(LOG_TAG, executionCommand.toString());
+        if(Logger.getLogLevel() >= Logger.LOG_LEVEL_VERBOSE)
+            Logger.logVerbose(LOG_TAG, executionCommand.toString());
 
         BackgroundJob task = new BackgroundJob(executionCommand, this);
 
@@ -328,65 +336,134 @@ public final class TermuxService extends Service {
     }
 
     /** Execute a shell command in a foreground terminal session. */
-    private void executeForegroundCommand(ExecutionCommand executionCommand) {
-        Logger.logDebug(LOG_TAG, "Starting foreground command");
+    private void executeTermuxSessionCommand(ExecutionCommand executionCommand) {
+        if (executionCommand == null) return;
+        
+        Logger.logDebug(LOG_TAG, "Starting foreground termux session command");
 
-        if(!executionCommand.setState(ExecutionState.EXECUTING))
-            return;
-
-        Logger.logDebug(LOG_TAG, executionCommand.toString());
-
-        TerminalSession newSession = createTerminalSession(executionCommand.executable, executionCommand.arguments, executionCommand.workingDirectory, executionCommand.isFailsafe);
+        String sessionName = null;
 
         // Transform executable path to session name, e.g. "/bin/do-something.sh" => "do something.sh".
         if (executionCommand.executable != null) {
-            int lastSlash = executionCommand.executable.lastIndexOf('/');
-            String name = (lastSlash == -1) ? executionCommand.executable : executionCommand.executable.substring(lastSlash + 1);
-            name = name.replace('-', ' ');
-            newSession.mSessionName = name;
+            sessionName = ShellUtils.getExecutableBasename(executionCommand.executable).replace('-', ' ');
         }
 
+        TermuxSession newTermuxSession = createTermuxSession(executionCommand, sessionName);
+        if (newTermuxSession == null) return;
+
+        handleSessionAction(TextDataUtils.getIntFromString(executionCommand.sessionAction,
+            TERMUX_SERVICE.VALUE_EXTRA_SESSION_ACTION_SWITCH_TO_NEW_SESSION_AND_OPEN_ACTIVITY),
+            newTermuxSession.getTerminalSession());
+    }
+
+    /**
+     * Create a termux session.
+     * Currently called by {@link TermuxSessionClient#addNewSession(boolean, String)} to add a new termux session.
+     */
+    @Nullable
+    public TermuxSession createTermuxSession(String executablePath, String[] arguments, String workingDirectory, boolean isFailSafe, String sessionName) {
+        return createTermuxSession(new ExecutionCommand(getNextExecutionId(), executablePath, arguments, workingDirectory, false, isFailSafe), sessionName);
+    }
+
+    /** Create a termux session. */
+    @Nullable
+    public synchronized TermuxSession createTermuxSession(ExecutionCommand executionCommand, String sessionName) {
+        if (executionCommand == null) return null;
+
+        Logger.logDebug(LOG_TAG, "Creating termux session");
+
+        if (executionCommand.inBackground) {
+            Logger.logDebug(LOG_TAG, "Ignoring a background execution command passed to createTermuxSession()");
+            return null;
+        }
+
+        if(Logger.getLogLevel() >= Logger.LOG_LEVEL_VERBOSE)
+            Logger.logVerbose(LOG_TAG, executionCommand.toString());
+        
+        TermuxSession newTermuxSession = TermuxSession.create(executionCommand, getTermuxSessionClient(), sessionName);
+        if (newTermuxSession == null) {
+            Logger.logError(LOG_TAG, "Failed to execute new termux session command for:\n" + executionCommand.toString());
+            return null;
+        };
+
+        mTermuxSessions.add(newTermuxSession);
+
         // Notify {@link TermuxSessionsListViewController} that sessions list has been updated if
         // activity in is foreground
         if(mTermuxSessionClient != null)
-            mTermuxSessionClient.terminalSessionListNotifyUpdated();
+            mTermuxSessionClient.termuxSessionListNotifyUpdated();
 
-        handleSessionAction(TextDataUtils.getIntFromString(executionCommand.sessionAction, TERMUX_SERVICE.VALUE_EXTRA_SESSION_ACTION_SWITCH_TO_NEW_SESSION_AND_OPEN_ACTIVITY), newSession);
+        updateNotification();
+        TermuxActivity.updateTermuxActivityStyling(this);
+
+        return newTermuxSession;
     }
 
-    private void setCurrentStoredSession(TerminalSession newSession) {
-        // Make the newly created session the current one to be displayed:
-        TermuxAppSharedPreferences preferences = new TermuxAppSharedPreferences(this);
-        preferences.setCurrentSession(newSession.mHandle);
+    /** Remove a termux session. */
+    public synchronized int removeTermuxSession(TerminalSession sessionToRemove) {
+        int index = getIndexOfSession(sessionToRemove);
+
+        if(index >= 0) {
+            TermuxSession termuxSession = mTermuxSessions.get(index);
+
+            if (termuxSession.getExecutionCommand().setState(ExecutionState.EXECUTED)) {
+                ;
+            }
+
+            mTermuxSessions.remove(termuxSession);
+
+            // Notify {@link TermuxSessionsListViewController} that sessions list has been updated if
+            // activity in is foreground
+            if(mTermuxSessionClient != null)
+                mTermuxSessionClient.termuxSessionListNotifyUpdated();
+        }
+
+        if (mTermuxSessions.isEmpty() && mWakeLock == null) {
+            // Finish if there are no sessions left and the wake lock is not held, otherwise keep the service alive if
+            // holding wake lock since there may be daemon processes (e.g. sshd) running.
+            requestStopService();
+        } else {
+            updateNotification();
+        }
+        return index;
     }
 
+    /** Finish all termux sessions by sending SIGKILL to their shells. */
+    private synchronized void finishAllTermuxSessions() {
+        for (int i = 0; i < mTermuxSessions.size(); i++)
+            mTermuxSessions.get(i).getTerminalSession().finishIfRunning();
+    }
+
+
+
     /** Process session action for new session. */
-    private void handleSessionAction(int sessionAction, TerminalSession newSession) {
-        Logger.logDebug(LOG_TAG, "Processing sessionAction \"" + sessionAction + "\" for session \"" + newSession.mSessionName + "\"");
+    private void handleSessionAction(int sessionAction, TerminalSession newTerminalSession) {
+        Logger.logDebug(LOG_TAG, "Processing sessionAction \"" + sessionAction + "\" for session \"" + newTerminalSession.mSessionName + "\"");
 
         switch (sessionAction) {
             case TERMUX_SERVICE.VALUE_EXTRA_SESSION_ACTION_SWITCH_TO_NEW_SESSION_AND_OPEN_ACTIVITY:
-                setCurrentStoredSession(newSession);
+                setCurrentStoredTerminalSession(newTerminalSession);
                 if(mTermuxSessionClient != null)
-                    mTermuxSessionClient.setCurrentSession(newSession);
+                    mTermuxSessionClient.setCurrentSession(newTerminalSession);
                 startTermuxActivity();
                 break;
             case TERMUX_SERVICE.VALUE_EXTRA_SESSION_ACTION_KEEP_CURRENT_SESSION_AND_OPEN_ACTIVITY:
-                if(mTerminalSessions.size() == 1)
-                    setCurrentStoredSession(newSession);
+                if(getTermuxSessionsSize() == 1)
+                    setCurrentStoredTerminalSession(newTerminalSession);
                 startTermuxActivity();
                 break;
             case TERMUX_SERVICE.VALUE_EXTRA_SESSION_ACTION_SWITCH_TO_NEW_SESSION_AND_DONT_OPEN_ACTIVITY:
-                setCurrentStoredSession(newSession);
+                setCurrentStoredTerminalSession(newTerminalSession);
                 if(mTermuxSessionClient != null)
-                    mTermuxSessionClient.setCurrentSession(newSession);
+                    mTermuxSessionClient.setCurrentSession(newTerminalSession);
                 break;
             case TERMUX_SERVICE.VALUE_EXTRA_SESSION_ACTION_KEEP_CURRENT_SESSION_AND_DONT_OPEN_ACTIVITY:
-                if(mTerminalSessions.size() == 1)
-                    setCurrentStoredSession(newSession);
+                if(getTermuxSessionsSize() == 1)
+                    setCurrentStoredTerminalSession(newTerminalSession);
                 break;
             default:
-                Logger.logError(LOG_TAG, "Invalid sessionAction: \"" + sessionAction + "\"");
+                Logger.logError(LOG_TAG, "Invalid sessionAction: \"" + sessionAction + "\". Force using default sessionAction.");
+                handleSessionAction(TERMUX_SERVICE.VALUE_EXTRA_SESSION_ACTION_SWITCH_TO_NEW_SESSION_AND_OPEN_ACTIVITY, newTerminalSession);
                 break;
         }
     }
@@ -396,78 +473,6 @@ public final class TermuxService extends Service {
         startActivity(new Intent(this, TermuxActivity.class).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK));
     }
 
-    /** Create a terminal session. */
-    public TerminalSession createTerminalSession(String executablePath, String[] arguments, String workingDirectory, boolean isFailSafe) {
-        TermuxConstants.TERMUX_HOME_DIR.mkdirs();
-
-        if (workingDirectory == null || workingDirectory.isEmpty()) workingDirectory = TermuxConstants.TERMUX_HOME_DIR_PATH;
-
-        String[] env = BackgroundJob.buildEnvironment(isFailSafe, workingDirectory);
-        boolean isLoginShell = false;
-
-        if (executablePath == null) {
-            if (!isFailSafe) {
-                for (String shellBinary : new String[]{"login", "bash", "zsh"}) {
-                    File shellFile = new File(TermuxConstants.TERMUX_BIN_PREFIX_DIR_PATH, shellBinary);
-                    if (shellFile.canExecute()) {
-                        executablePath = shellFile.getAbsolutePath();
-                        break;
-                    }
-                }
-            }
-
-            if (executablePath == null) {
-                // Fall back to system shell as last resort:
-                executablePath = "/system/bin/sh";
-            }
-            isLoginShell = true;
-        }
-
-        String[] processArgs = BackgroundJob.setupProcessArgs(executablePath, arguments);
-        executablePath = processArgs[0];
-        int lastSlashIndex = executablePath.lastIndexOf('/');
-        String processName = (isLoginShell ? "-" : "") +
-            (lastSlashIndex == -1 ? executablePath : executablePath.substring(lastSlashIndex + 1));
-
-        String[] args = new String[processArgs.length];
-        args[0] = processName;
-        if (processArgs.length > 1) System.arraycopy(processArgs, 1, args, 1, processArgs.length - 1);
-
-        TerminalSession session = new TerminalSession(executablePath, workingDirectory, args, env, getTermuxSessionClient());
-        mTerminalSessions.add(session);
-        updateNotification();
-
-        // Make sure that terminal styling is always applied.
-        Intent stylingIntent = new Intent(TERMUX_ACTIVITY.ACTION_RELOAD_STYLE);
-        stylingIntent.putExtra(TERMUX_ACTIVITY.EXTRA_RELOAD_STYLE, "styling");
-        sendBroadcast(stylingIntent);
-
-        return session;
-    }
-
-    /** Remove a terminal session. */
-    public int removeTerminalSession(TerminalSession sessionToRemove) {
-        int indexOfRemoved = mTerminalSessions.indexOf(sessionToRemove);
-        mTerminalSessions.remove(indexOfRemoved);
-
-        if (mTerminalSessions.isEmpty() && mWakeLock == null) {
-            // Finish if there are no sessions left and the wake lock is not held, otherwise keep the service alive if
-            // holding wake lock since there may be daemon processes (e.g. sshd) running.
-            requestStopService();
-        } else {
-            updateNotification();
-        }
-        return indexOfRemoved;
-    }
-
-    /** Finish all terminal sessions by sending SIGKILL to their shells. */
-    private void finishAllTerminalSessions() {
-        for (int i = 0; i < mTerminalSessions.size(); i++)
-            mTerminalSessions.get(i).finishIfRunning();
-    }
-
-
-
     /** If {@link TermuxActivity} has not bound to the {@link TermuxService} yet or is destroyed, then
      * interface functions requiring the activity should not be available to the terminal sessions,
      * so we just return the {@link #mTermuxSessionClientBase}. Once {@link TermuxActivity} bind
@@ -479,7 +484,7 @@ public final class TermuxService extends Service {
      * @return Returns the {@link TermuxSessionClient} if {@link TermuxActivity} has bound with
      * {@link TermuxService}, otherwise {@link TermuxSessionClientBase}.
      */
-    public TermuxSessionClientBase getTermuxSessionClient() {
+    public synchronized TermuxSessionClientBase getTermuxSessionClient() {
         if (mTermuxSessionClient != null)
             return mTermuxSessionClient;
         else
@@ -494,20 +499,20 @@ public final class TermuxService extends Service {
      * @param termuxSessionClient The {@link TermuxSessionClient} object that fully
      * implements the {@link TerminalSessionClient} interface.
      */
-    public void setTermuxSessionClient(TermuxSessionClient termuxSessionClient) {
+    public synchronized void setTermuxSessionClient(TermuxSessionClient termuxSessionClient) {
         mTermuxSessionClient = termuxSessionClient;
 
-        for (int i = 0; i < mTerminalSessions.size(); i++)
-            mTerminalSessions.get(i).updateTerminalSessionClient(mTermuxSessionClient);
+        for (int i = 0; i < mTermuxSessions.size(); i++)
+            mTermuxSessions.get(i).getTerminalSession().updateTerminalSessionClient(mTermuxSessionClient);
     }
 
     /** This should be called when {@link TermuxActivity} has been destroyed and in {@link #onUnbind(Intent)}
      * so that the {@link TermuxService} and {@link TerminalSession} and {@link TerminalEmulator}
      * clients do not hold an activity references.
      */
-    public void unsetTermuxSessionClient() {
-        for (int i = 0; i < mTerminalSessions.size(); i++)
-            mTerminalSessions.get(i).updateTerminalSessionClient(mTermuxSessionClientBase);
+    public synchronized void unsetTermuxSessionClient() {
+        for (int i = 0; i < mTermuxSessions.size(); i++)
+            mTermuxSessions.get(i).getTerminalSession().updateTerminalSessionClient(mTermuxSessionClientBase);
 
         mTermuxSessionClient = null;
     }
@@ -521,7 +526,7 @@ public final class TermuxService extends Service {
         notifyIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
         PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, notifyIntent, 0);
 
-        int sessionCount = mTerminalSessions.size();
+        int sessionCount = getTermuxSessionsSize();
         int taskCount = mBackgroundTasks.size();
         String contentText = sessionCount + " session" + (sessionCount == 1 ? "" : "s");
         if (taskCount > 0) {
@@ -582,7 +587,7 @@ public final class TermuxService extends Service {
 
     /** Update the shown foreground service notification after making any changes that affect it. */
     void updateNotification() {
-        if (mWakeLock == null && mTerminalSessions.isEmpty() && mBackgroundTasks.isEmpty()) {
+        if (mWakeLock == null && mTermuxSessions.isEmpty() && mBackgroundTasks.isEmpty()) {
             // Exit if we are updating after the user disabled all locks with no sessions or tasks running.
             requestStopService();
         } else {
@@ -592,16 +597,63 @@ public final class TermuxService extends Service {
 
 
 
+    private void setCurrentStoredTerminalSession(TerminalSession session) {
+        if(session == null) return;
+        // Make the newly created session the current one to be displayed:
+        TermuxAppSharedPreferences preferences = new TermuxAppSharedPreferences(this);
+        preferences.setCurrentSession(session.mHandle);
+    }
+
+    public synchronized boolean isTermuxSessionsEmpty() {
+        return mTermuxSessions.isEmpty();
+    }
+
+    public synchronized int getTermuxSessionsSize() {
+        return mTermuxSessions.size();
+    }
+
+    public synchronized List<TermuxSession> getTermuxSessions() {
+        return mTermuxSessions;
+    }
+
+    @Nullable
+    public synchronized TermuxSession getTermuxSession(int index) {
+        if(index >= 0 && index < mTermuxSessions.size())
+            return mTermuxSessions.get(index);
+        else
+            return null;
+    }
+
+    public synchronized TermuxSession getLastTermuxSession() {
+        return mTermuxSessions.isEmpty() ? null : mTermuxSessions.get(mTermuxSessions.size() - 1);
+    }
+
+    public synchronized int getIndexOfSession(TerminalSession terminalSession) {
+        for (int i = 0; i < mTermuxSessions.size(); i++) {
+            if (mTermuxSessions.get(i).getTerminalSession().equals(terminalSession))
+                return i;
+        }
+        return -1;
+    }
+
+    public synchronized TerminalSession getTerminalSessionForHandle(String sessionHandle) {
+        TerminalSession terminalSession;
+        for (int i = 0, len = mTermuxSessions.size(); i < len; i++) {
+            terminalSession = mTermuxSessions.get(i).getTerminalSession();
+            if (terminalSession.mHandle.equals(sessionHandle))
+                return terminalSession;
+        }
+        return null;
+    }
+
+
+
+    public static synchronized int getNextExecutionId() {
+        return EXECUTION_ID++;
+    }
+
     public boolean wantsToStop() {
         return mWantsToStop;
     }
 
-    public List<TerminalSession> getSessions() {
-        return mTerminalSessions;
-    }
-
-    synchronized public static int getNextExecutionId() {
-        return EXECUTION_ID++;
-    }
-
 }

app/src/main/java/com/termux/app/terminal/TermuxSession.java

@@ -0,0 +1,87 @@
+package com.termux.app.terminal;
+
+import com.termux.app.TermuxConstants;
+import com.termux.app.utils.Logger;
+import com.termux.app.utils.ShellUtils;
+import com.termux.models.ExecutionCommand;
+import com.termux.terminal.TerminalSession;
+
+import java.io.File;
+
+/**
+ * A class that maintains info for foreground Termux sessions.
+ * It also provides a way to link each {@link TerminalSession} with the {@link ExecutionCommand}
+ * that started it.
+ */
+public class TermuxSession {
+
+    private final TerminalSession mTerminalSession;
+    private final ExecutionCommand mExecutionCommand;
+
+    private static final String LOG_TAG = "TermuxSession";
+
+    private TermuxSession(TerminalSession terminalSession, ExecutionCommand executionCommand) {
+        this.mTerminalSession = terminalSession;
+        this.mExecutionCommand = executionCommand;
+    }
+
+    public static TermuxSession create(ExecutionCommand executionCommand, TermuxSessionClientBase termuxSessionClient, String sessionName) {
+        TermuxConstants.TERMUX_HOME_DIR.mkdirs();
+
+        if (executionCommand.workingDirectory == null || executionCommand.workingDirectory.isEmpty()) executionCommand.workingDirectory = TermuxConstants.TERMUX_HOME_DIR_PATH;
+
+        String[] environment = ShellUtils.buildEnvironment(executionCommand.isFailsafe, executionCommand.workingDirectory);
+        boolean isLoginShell = false;
+
+        if (executionCommand.executable == null) {
+            if (!executionCommand.isFailsafe) {
+                for (String shellBinary : new String[]{"login", "bash", "zsh"}) {
+                    File shellFile = new File(TermuxConstants.TERMUX_BIN_PREFIX_DIR_PATH, shellBinary);
+                    if (shellFile.canExecute()) {
+                        executionCommand.executable = shellFile.getAbsolutePath();
+                        break;
+                    }
+                }
+            }
+
+            if (executionCommand.executable == null) {
+                // Fall back to system shell as last resort:
+                executionCommand.executable = "/system/bin/sh";
+            }
+            isLoginShell = true;
+        }
+
+        String[] processArgs = ShellUtils.setupProcessArgs(executionCommand.executable, executionCommand.arguments);
+
+        executionCommand.executable = processArgs[0];
+        String processName = (isLoginShell ? "-" : "") + ShellUtils.getExecutableBasename(executionCommand.executable);
+
+        String[] arguments = new String[processArgs.length];
+        arguments[0] = processName;
+        if (processArgs.length > 1) System.arraycopy(processArgs, 1, arguments, 1, processArgs.length - 1);
+
+        executionCommand.arguments = arguments;
+
+        if(!executionCommand.setState(ExecutionCommand.ExecutionState.EXECUTING))
+            return null;
+
+        Logger.logDebug(LOG_TAG, executionCommand.toString());
+
+        TerminalSession terminalSession = new TerminalSession(executionCommand.executable, executionCommand.workingDirectory, executionCommand.arguments, environment, termuxSessionClient);
+
+        if (sessionName != null) {
+            terminalSession.mSessionName = sessionName;
+        }
+
+        return new TermuxSession(terminalSession, executionCommand);
+    }
+
+    public TerminalSession getTerminalSession() {
+        return mTerminalSession;
+    }
+
+    public ExecutionCommand getExecutionCommand() {
+        return mExecutionCommand;
+    }
+
+}

app/src/main/java/com/termux/app/terminal/TermuxSessionClient.java

@@ -27,7 +27,6 @@ import com.termux.terminal.TextStyle;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.InputStream;
-import java.util.List;
 import java.util.Properties;
 
 public class TermuxSessionClient extends TermuxSessionClientBase {
@@ -68,7 +67,7 @@ public class TermuxSessionClient extends TermuxSessionClientBase {
             mActivity.showToast(toToastTitle(updatedSession), true);
         }
 
-        terminalSessionListNotifyUpdated();
+        termuxSessionListNotifyUpdated();
     }
 
     @Override
@@ -81,7 +80,7 @@ public class TermuxSessionClient extends TermuxSessionClientBase {
 
         if (mActivity.isVisible() && finishedSession != mActivity.getCurrentSession()) {
             // Show toast for non-current sessions that exit.
-            int indexOfSession = mActivity.getTermuxService().getSessions().indexOf(finishedSession);
+            int indexOfSession = mActivity.getTermuxService().getIndexOfSession(finishedSession);
             // Verify that session was not removed before we got told about it finishing:
             if (indexOfSession >= 0)
                 mActivity.showToast(toToastTitle(finishedSession) + " - exited", true);
@@ -90,7 +89,7 @@ public class TermuxSessionClient extends TermuxSessionClientBase {
         if (mActivity.getPackageManager().hasSystemFeature(PackageManager.FEATURE_LEANBACK)) {
             // On Android TV devices we need to use older behaviour because we may
             // not be able to have multiple launcher icons.
-            if (mActivity.getTermuxService().getSessions().size() > 1) {
+            if (mActivity.getTermuxService().getTermuxSessionsSize() > 1) {
                 removeFinishedSession(finishedSession);
             }
         } else {
@@ -100,8 +99,6 @@ public class TermuxSessionClient extends TermuxSessionClientBase {
                 removeFinishedSession(finishedSession);
             }
         }
-
-        terminalSessionListNotifyUpdated();
     }
 
     @Override
@@ -138,38 +135,49 @@ public class TermuxSessionClient extends TermuxSessionClientBase {
 
 
 
-    /** Try switching to session and note about it, but do nothing if already displaying the session. */
+    /** Try switching to session. */
     public void setCurrentSession(TerminalSession session) {
+        if(session == null) return;
+
         if (mActivity.getTerminalView().attachSession(session)) {
-            noteSessionInfo();
-            updateBackgroundColor();
+            // notify about switched session if not already displaying the session
+            notifyOfSessionChange();
         }
+
+        // We call the following even when the session is already being displayed since config may
+        // be stale, like current session not selected or scrolled to.
+        checkAndScrollToSession(session);
+        updateBackgroundColor();
     }
 
-    void noteSessionInfo() {
+    void notifyOfSessionChange() {
         if (!mActivity.isVisible()) return;
 
         TerminalSession session = mActivity.getCurrentSession();
-        final int indexOfSession = mActivity.getTermuxService().getSessions().indexOf(session);
         mActivity.showToast(toToastTitle(session), false);
-        terminalSessionListNotifyUpdated();
-
-        final ListView termuxSessionsListView = mActivity.findViewById(R.id.terminal_sessions_list);
-        termuxSessionsListView.setItemChecked(indexOfSession, true);
-        termuxSessionsListView.smoothScrollToPosition(indexOfSession);
     }
 
     public void switchToSession(boolean forward) {
         TermuxService service = mActivity.getTermuxService();
 
-        TerminalSession currentSession = mActivity.getCurrentSession();
-        int index = service.getSessions().indexOf(currentSession);
+        TerminalSession currentTerminalSession = mActivity.getCurrentSession();
+        int index = service.getIndexOfSession(currentTerminalSession);
+        int size = service.getTermuxSessionsSize();
         if (forward) {
-            if (++index >= service.getSessions().size()) index = 0;
+            if (++index >= size) index = 0;
         } else {
-            if (--index < 0) index = service.getSessions().size() - 1;
+            if (--index < 0) index = size - 1;
         }
-        setCurrentSession(service.getSessions().get(index));
+
+        TermuxSession termuxSession = service.getTermuxSession(index);
+        if(termuxSession != null)
+            setCurrentSession(termuxSession.getTerminalSession());
+    }
+
+    public void switchToSession(int index) {
+        TermuxSession termuxSession = mActivity.getTermuxService().getTermuxSession(index);
+        if(termuxSession != null)
+            setCurrentSession(termuxSession.getTerminalSession());
     }
 
     @SuppressLint("InflateParams")
@@ -178,12 +186,12 @@ public class TermuxSessionClient extends TermuxSessionClientBase {
 
         DialogUtils.textInput(mActivity, R.string.title_rename_session, sessionToRename.mSessionName, R.string.action_rename_session_confirm, text -> {
             sessionToRename.mSessionName = text;
-            terminalSessionListNotifyUpdated();
+            termuxSessionListNotifyUpdated();
         }, -1, null, -1, null, null);
     }
 
     public void addNewSession(boolean isFailSafe, String sessionName) {
-        if (mActivity.getTermuxService().getSessions().size() >= MAX_SESSIONS) {
+        if (mActivity.getTermuxService().getTermuxSessionsSize() >= MAX_SESSIONS) {
             new AlertDialog.Builder(mActivity).setTitle(R.string.title_max_terminals_reached).setMessage(R.string.msg_max_terminals_reached)
                 .setPositiveButton(android.R.string.ok, null).show();
         } else {
@@ -196,11 +204,12 @@ public class TermuxSessionClient extends TermuxSessionClientBase {
                 workingDirectory = currentSession.getCwd();
             }
 
-            TerminalSession newSession = mActivity.getTermuxService().createTerminalSession(null, null, workingDirectory, isFailSafe);
-            if (sessionName != null) {
-                newSession.mSessionName = sessionName;
-            }
-            setCurrentSession(newSession);
+            TermuxSession newTermuxSession = mActivity.getTermuxService().createTermuxSession(null, null, workingDirectory, isFailSafe, sessionName);
+            if (newTermuxSession == null) return;
+
+            TerminalSession newTerminalSession = newTermuxSession.getTerminalSession();
+            setCurrentSession(newTerminalSession);
+
             mActivity.getDrawer().closeDrawers();
         }
     }
@@ -222,8 +231,11 @@ public class TermuxSessionClient extends TermuxSessionClientBase {
             return stored;
         } else {
             // Else return the last session currently running
-            List<TerminalSession> sessions = mActivity.getTermuxService().getSessions();
-            return sessions.isEmpty() ? null : sessions.get(sessions.size() - 1);
+            TermuxSession termuxSession = mActivity.getTermuxService().getLastTermuxSession();
+            if(termuxSession != null)
+                return termuxSession.getTerminalSession();
+            else
+                return null;
         }
     }
 
@@ -235,41 +247,50 @@ public class TermuxSessionClient extends TermuxSessionClientBase {
             return null;
 
         // Check if the session handle found matches one of the currently running sessions
-        List<TerminalSession> sessions = context.getTermuxService().getSessions();
-        for (int i = 0, len = sessions.size(); i < len; i++) {
-            TerminalSession session = sessions.get(i);
-            if (session.mHandle.equals(sessionHandle))
-                return session;
-        }
-
-        return null;
+        return context.getTermuxService().getTerminalSessionForHandle(sessionHandle);
     }
 
     public void removeFinishedSession(TerminalSession finishedSession) {
         // Return pressed with finished session - remove it.
         TermuxService service = mActivity.getTermuxService();
 
-        int index = service.removeTerminalSession(finishedSession);
-        terminalSessionListNotifyUpdated();
-        if (mActivity.getTermuxService().getSessions().isEmpty()) {
+        int index = service.removeTermuxSession(finishedSession);
+        int size = mActivity.getTermuxService().getTermuxSessionsSize();
+        if (size == 0) {
             // There are no sessions to show, so finish the activity.
             mActivity.finishActivityIfNotFinishing();
         } else {
-            if (index >= service.getSessions().size()) {
-                index = service.getSessions().size() - 1;
+            if (index >= size) {
+                index = size - 1;
             }
-            setCurrentSession(service.getSessions().get(index));
+            TermuxSession termuxSession = service.getTermuxSession(index);
+            if(termuxSession != null)
+                setCurrentSession(termuxSession.getTerminalSession());
         }
     }
 
-    public void terminalSessionListNotifyUpdated() {
-        mActivity.terminalSessionListNotifyUpdated();
+    public void termuxSessionListNotifyUpdated() {
+        mActivity.termuxSessionListNotifyUpdated();
+    }
+
+    public void checkAndScrollToSession(TerminalSession session) {
+        if (!mActivity.isVisible()) return;
+        final int indexOfSession = mActivity.getTermuxService().getIndexOfSession(session);
+        if (indexOfSession < 0) return;
+        final ListView termuxSessionsListView = mActivity.findViewById(R.id.terminal_sessions_list);
+        if(termuxSessionsListView == null) return;
+
+        termuxSessionsListView.setItemChecked(indexOfSession, true);
+        // Delay is necessary otherwise sometimes scroll to newly added session does not happen
+        termuxSessionsListView.postDelayed(() -> termuxSessionsListView.smoothScrollToPosition(indexOfSession), 1000);
+
+        Logger.logError("scrolled to " + indexOfSession);
     }
 
 
-
     String toToastTitle(TerminalSession session) {
-        final int indexOfSession = mActivity.getTermuxService().getSessions().indexOf(session);
+        final int indexOfSession = mActivity.getTermuxService().getIndexOfSession(session);
+        if (indexOfSession < 0) return null;
         StringBuilder toastTitle = new StringBuilder("[" + (indexOfSession + 1) + "]");
         if (!TextUtils.isEmpty(session.mSessionName)) {
             toastTitle.append(" ").append(session.mSessionName);
@@ -311,6 +332,7 @@ public class TermuxSessionClient extends TermuxSessionClientBase {
     }
 
     public void updateBackgroundColor() {
+        if (!mActivity.isVisible()) return;
         TerminalSession session = mActivity.getCurrentSession();
         if (session != null && session.getEmulator() != null) {
             mActivity.getWindow().getDecorView().setBackgroundColor(session.getEmulator().mColors.mCurrentColors[TextStyle.COLOR_INDEX_BACKGROUND]);

app/src/main/java/com/termux/app/terminal/TermuxSessionsListViewController.java

@@ -24,14 +24,14 @@ import com.termux.terminal.TerminalSession;
 
 import java.util.List;
 
-public class TermuxSessionsListViewController extends ArrayAdapter<TerminalSession> implements AdapterView.OnItemClickListener, AdapterView.OnItemLongClickListener {
+public class TermuxSessionsListViewController extends ArrayAdapter<TermuxSession> implements AdapterView.OnItemClickListener, AdapterView.OnItemLongClickListener {
 
     final TermuxActivity mActivity;
 
     final StyleSpan boldSpan = new StyleSpan(Typeface.BOLD);
     final StyleSpan italicSpan = new StyleSpan(Typeface.ITALIC);
 
-    public TermuxSessionsListViewController(TermuxActivity activity, List<TerminalSession> sessionList) {
+    public TermuxSessionsListViewController(TermuxActivity activity, List<TermuxSession> sessionList) {
         super(activity.getApplicationContext(), R.layout.item_terminal_sessions_list, sessionList);
         this.mActivity = activity;
     }
@@ -48,7 +48,7 @@ public class TermuxSessionsListViewController extends ArrayAdapter<TerminalSessi
 
         TextView sessionTitleView = sessionRowView.findViewById(R.id.session_title);
 
-        TerminalSession sessionAtRow = getItem(position);
+        TerminalSession sessionAtRow = getItem(position).getTerminalSession();
         if (sessionAtRow == null) {
             sessionTitleView.setText("null session");
             return sessionRowView;
@@ -91,16 +91,16 @@ public class TermuxSessionsListViewController extends ArrayAdapter<TerminalSessi
 
     @Override
     public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
-        TerminalSession clickedSession = getItem(position);
-        mActivity.getTermuxSessionClient().setCurrentSession(clickedSession);
+        TermuxSession clickedSession = getItem(position);
+        mActivity.getTermuxSessionClient().setCurrentSession(clickedSession.getTerminalSession());
         mActivity.getDrawer().closeDrawers();
 
     }
 
     @Override
     public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
-        final TerminalSession selectedSession = getItem(position);
-        mActivity.getTermuxSessionClient().renameSession(selectedSession);
+        final TermuxSession selectedSession = getItem(position);
+        mActivity.getTermuxSessionClient().renameSession(selectedSession.getTerminalSession());
         return true;
     }
 

app/src/main/java/com/termux/app/terminal/TermuxViewClient.java

@@ -20,7 +20,6 @@ import android.widget.Toast;
 
 import com.termux.R;
 import com.termux.app.TermuxActivity;
-import com.termux.app.TermuxService;
 import com.termux.app.terminal.io.KeyboardShortcut;
 import com.termux.app.terminal.io.extrakeys.ExtraKeysView;
 import com.termux.app.settings.properties.TermuxPropertyConstants;
@@ -135,10 +134,8 @@ public class TermuxViewClient implements TerminalViewClient {
             } else if (unicodeChar == '-') {
                 changeFontSize(false);
             } else if (unicodeChar >= '1' && unicodeChar <= '9') {
-                int num = unicodeChar - '1';
-                TermuxService service = mActivity.getTermuxService();
-                if (service.getSessions().size() > num)
-                    mTermuxSessionClient.setCurrentSession(service.getSessions().get(num));
+                int index = unicodeChar - '1';
+                mTermuxSessionClient.switchToSession(index);
             }
             return true;
         }