Added: Add ShellCommandShellEnvironment and TermuxShellCommandShellEnvironment to export ExecutionCommand variables

This adds onto f102ea20 to build termux environment. Variables for `ExecutionCommand` app have the `SHELL_CMD__` scope. Docs will be provided for details of the variables.

- `SHELL_CMD__SHELL_ID`
- `SHELL_CMD__SHELL_NAME`
- `SHELL_CMD__APP_SHELL_NUMBER_SINCE_BOOT`
- `SHELL_CMD__TERMINAL_SESSION_NUMBER_SINCE_BOOT`
- `SHELL_CMD__APP_SHELL_NUMBER_SINCE_APP_START`
- `SHELL_CMD__TERMINAL_SESSION_NUMBER_SINCE_APP_START`

The commit also adds `SystemEventReceiver` to Termux app that will receive `ACTION_BOOT_COMPLETED`.

app/src/main/AndroidManifest.xml

@@ -34,6 +34,7 @@
     <uses-permission android:name="android.permission.DUMP" />
     <uses-permission android:name="android.permission.WRITE_SECURE_SETTINGS" />
     <uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES" />
+    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
     <uses-permission android:name="android.permission.PACKAGE_USAGE_STATS" tools:ignore="ProtectedPermissions" />
 
     <application
@@ -169,6 +170,14 @@
             android:name=".app.TermuxOpenReceiver"
             android:exported="false" />
 
+        <receiver
+            android:name=".app.event.SystemEventReceiver"
+            android:exported="false">
+            <intent-filter>
+                <action android:name="android.intent.action.BOOT_COMPLETED" />
+            </intent-filter>
+        </receiver>
+
         <receiver
             android:name=".shared.activities.ReportActivity$ReportActivityBroadcastReceiver"
             android:exported="false" />

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

@@ -170,6 +170,8 @@ public final class TermuxService extends Service implements AppShell.AppShellCli
         actionReleaseWakeLock(false);
         if (!mWantsToStop)
             killAllTermuxExecutionCommands();
+
+        TermuxShellManager.onAppExit(this);
         runStopForeground();
     }
 
@@ -463,6 +465,8 @@ public final class TermuxService extends Service implements AppShell.AppShellCli
             return null;
         }
 
+        executionCommand.setShellCommandShellEnvironment = true;
+
         if (Logger.getLogLevel() >= Logger.LOG_LEVEL_VERBOSE)
             Logger.logVerboseExtended(LOG_TAG, executionCommand.toString());
 
@@ -571,13 +575,15 @@ public final class TermuxService extends Service implements AppShell.AppShellCli
             return null;
         }
 
+        executionCommand.setShellCommandShellEnvironment = true;
+        executionCommand.terminalTranscriptRows = mProperties.getTerminalTranscriptRows();
+
         if (Logger.getLogLevel() >= Logger.LOG_LEVEL_VERBOSE)
             Logger.logVerboseExtended(LOG_TAG, executionCommand.toString());
 
         // If the execution command was started for a plugin, only then will the stdout be set
         // Otherwise if command was manually started by the user like by adding a new terminal session,
         // then no need to set stdout
-        executionCommand.terminalTranscriptRows = mProperties.getTerminalTranscriptRows();
         TermuxSession newTermuxSession = TermuxSession.execute(this, executionCommand, getTermuxTerminalSessionClient(),
             this, new TermuxShellEnvironment(), null, executionCommand.isPluginExecutionCommand);
         if (newTermuxSession == null) {

app/src/main/java/com/termux/app/event/SystemEventReceiver.java

@@ -0,0 +1,47 @@
+package com.termux.app.event;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.termux.shared.data.IntentUtils;
+import com.termux.shared.logger.Logger;
+import com.termux.shared.termux.shell.TermuxShellManager;
+
+public class SystemEventReceiver extends BroadcastReceiver {
+
+    private static SystemEventReceiver mInstance;
+
+    private static final String LOG_TAG = "SystemEventReceiver";
+
+    public static synchronized SystemEventReceiver getInstance() {
+        if (mInstance == null) {
+            mInstance = new SystemEventReceiver();
+        }
+        return mInstance;
+    }
+
+    @Override
+    public void onReceive(@NonNull Context context, @Nullable Intent intent) {
+        if (intent == null) return;
+        Logger.logDebug(LOG_TAG, "Intent Received:\n" + IntentUtils.getIntentString(intent));
+
+        String action = intent.getAction();
+        if (action == null) return;
+
+        switch (action) {
+            case Intent.ACTION_BOOT_COMPLETED:
+                onActionBootCompleted(context, intent);
+                break;
+            default:
+                Logger.logError(LOG_TAG, "Invalid action \"" + action + "\" passed to " + LOG_TAG);
+        }
+    }
+
+    public synchronized void onActionBootCompleted(@NonNull Context context, @NonNull Intent intent) {
+        TermuxShellManager.onActionBootCompleted(context, intent);
+    }
+
+}