Run shell on the Flatpak host

When Terminal is running on Flatpak we need to access the host
system, otherwise the app is pretty useless.

Closes: #36

src/lib/CMakeLists.txt

@@ -43,6 +43,8 @@ add_library(qmltermwidget STATIC
     kptydevice.h
     kptyprocess.cpp
     kptyprocess.h
+    utils.cpp
+    utils.h
 )
 target_include_directories(qmltermwidget
     PUBLIC

src/lib/Session.cpp

@@ -44,6 +44,7 @@
 #include "TerminalDisplay.h"
 #include "ShellCommand.h"
 #include "Vt102Emulation.h"
+#include "utils.h"
 
 // QMLTermWidget
 #include <QQuickWindow>
@@ -330,13 +331,40 @@ void Session::run()
     // the background color is deemed dark or not
     QString backgroundColorHint = _hasDarkBackground ? "COLORFGBG=15;0" : "COLORFGBG=0;15";
 
+    QStringList environmentVars = _environment;
+    environmentVars.append(backgroundColorHint);
+
+    // If we are running on Flatpak, we should have access to the host
+    if (isRunningOnFlatpak()) {
+        QStringList flatpakArgs;
+        flatpakArgs << QLatin1String("--host") << QLatin1String("--watch-bus");
+
+        for (const QString &envLine : environmentVars)
+            flatpakArgs << QStringLiteral("--env=%1").arg(envLine);
+
+        QStringList whitelist;
+        whitelist
+                << QLatin1String("TERM") << QLatin1String("PATH")
+                << QLatin1String("EDITOR") << QLatin1String("PS1")
+                << QLatin1String("DISPLAY") << QLatin1String("WAYLAND_DISPLAY");
+        for (const QString &envName : whitelist) {
+            const QString value = qEnvironmentVariable(qPrintable(envName));
+            if (!value.isEmpty())
+                flatpakArgs << QStringLiteral("--env=%1=%2").arg(envName).arg(value);
+        }
+
+        flatpakArgs << exec;
+        exec = QLatin1String("/usr/bin/flatpak-spawn");
+        arguments = flatpakArgs;
+    }
+
     /* if we do all the checking if this shell exists then we use it ;)
      * Dont know about the arguments though.. maybe youll need some more checking im not sure
      * However this works on Arch and FreeBSD now.
      */
     int result = _shellProcess->start(exec,
                                       arguments,
-                                      _environment << backgroundColorHint,
+                                      environmentVars,
                                       windowId(),
                                       _addToUtmp);
 

src/lib/kpty.cpp

@@ -145,6 +145,8 @@ extern "C" {
 //#include <kdebug.h>
 //#include <kstandarddirs.h>  // findExe
 
+#include "utils.h"
+
 // not defined on HP-UX for example
 #ifndef CTRL
 # define CTRL(x) ((x) & 037)
@@ -474,13 +476,15 @@ void KPty::setCTty()
     // and get rid of the old controlling terminal.
     setsid();
 
-    // make our slave pty the new controlling terminal.
+    if (!isRunningOnFlatpak()) {
+        // make our slave pty the new controlling terminal.
 #ifdef TIOCSCTTY
-    ioctl(d->slaveFd, TIOCSCTTY, 0);
+        ioctl(d->slaveFd, TIOCSCTTY, 0);
 #else
-    // __svr4__ hack: the first tty opened after setsid() becomes controlling tty
-    ::close(::open(d->ttyName, O_WRONLY, 0));
+        // __svr4__ hack: the first tty opened after setsid() becomes controlling tty
+        ::close(::open(d->ttyName, O_WRONLY, 0));
 #endif
+    }
 
     // make our new process group the foreground group on the pty
     int pgrp = getpid();

src/lib/utils.cpp

@@ -0,0 +1,31 @@
+/****************************************************************************
+ * This file is part of Liri.
+ *
+ * Copyright (C) 2019 Pier Luigi Fiorini <[email protected]>
+ *
+ * $BEGIN_LICENSE:LGPLv3+$
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * $END_LICENSE$
+ ***************************************************************************/
+
+#include <QFile>
+
+#include "utils.h"
+
+bool isRunningOnFlatpak()
+{
+    return QFile::exists(QLatin1String("/.flatpak-info"));
+}

src/lib/utils.h

@@ -0,0 +1,29 @@
+/****************************************************************************
+ * This file is part of Liri.
+ *
+ * Copyright (C) 2019 Pier Luigi Fiorini <[email protected]>
+ *
+ * $BEGIN_LICENSE:LGPLv3+$
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * $END_LICENSE$
+ ***************************************************************************/
+
+#ifndef UTILS_H
+#define UTILS_H
+
+bool isRunningOnFlatpak();
+
+#endif // UTILS_H