Merge pull request #15 from Droid-Deck/feat/droiddeck-steam-hostname

Make Steam identify DroidDeck as the host

app/src/main/java/com/droiddeck/launcher/runtime/LinuxRuntime.java

@@ -5,6 +5,7 @@ import android.os.Process;
 import android.system.ErrnoException;
 import android.system.Os;
 import android.system.StructStat;
+import android.system.StructUtsname;
 
 
 import java.io.File;
@@ -32,6 +33,7 @@ public final class LinuxRuntime {
     /** Shortcut extra naming which of the modes above a Linux entry launches. */
     public static final String EXTRA_LINUX_MODE = "linux_mode";
     private static final String KGSL_DEVICE = "/dev/kgsl-3d0";
+    private static final String GUEST_HOSTNAME = "DroidDeck";
     /** Where every Linux session's debug log lands: public, so a user can just hand the folder over. */
     public static final String DEBUG_LOG_DIR = "DroidDeck";
 
@@ -116,6 +118,8 @@ public final class LinuxRuntime {
         List<String> cmd = new ArrayList<>();
         cmd.add(prootBinary(context).getPath());
         cmd.add("--kill-on-exit");
+        // Preserve the host kernel identity while giving the guest the app's branded host name.
+        cmd.add("--kernel-release=" + guestUtsname());
         // Android's app seccomp policy traps the whole set*id family. Xwayland's Popen() calls
         // setgid()/setuid() before it execs xkbcomp and _exit(127)s when they fail, so without
         // this the keymap never compiles and Xwayland dies. -i makes proot answer those calls
@@ -245,6 +249,13 @@ public final class LinuxRuntime {
         cmd.add(spec);
     }
 
+    /** PRoot's complex -k format: sysname, nodename, release, version, machine, domain, HWCAP. */
+    private static String guestUtsname() {
+        StructUtsname host = Os.uname();
+        return "\\" + host.sysname + "\\" + GUEST_HOSTNAME + "\\" + host.release
+                + "\\" + host.version + "\\" + host.machine + "\\localdomain\\-1\\";
+    }
+
     /** X access control and Steam look the session user up by uid: the app uid is root inside. */
     public static void writeAccounts(Context context) throws IOException {
         File root = rootDir(context);

app/src/main/java/com/droiddeck/launcher/session/SessionService.kt

@@ -601,7 +601,9 @@ class SessionService : Service() {
         components.add(networkLink)
         components.forEach { it.start() }
 
-        val line = command.joinToString(" ") { it.replace(" ", "\\ ") }
+        val line = command.joinToString(" ") {
+            it.replace("\\", "\\\\").replace(" ", "\\ ")
+        }
         watchLaunchRequests(sessionRoot)
         // One session replacing another (the desktop's Steam launchers): the old proot is killed
         // by the teardown a second after the new one has started, and its exit used to arrive