Fix systemless hosts installation

app/apk/src/main/java/com/topjohnwu/magisk/ui/settings/SettingsViewModel.kt

@@ -22,11 +22,11 @@ import com.topjohnwu.magisk.core.ktx.activity
 import com.topjohnwu.magisk.core.ktx.toast
 import com.topjohnwu.magisk.core.tasks.AppMigration
 import com.topjohnwu.magisk.core.utils.LocaleSetting
+import com.topjohnwu.magisk.core.utils.RootUtils
 import com.topjohnwu.magisk.databinding.bindExtra
 import com.topjohnwu.magisk.events.AddHomeIconEvent
 import com.topjohnwu.magisk.events.AuthEvent
 import com.topjohnwu.magisk.events.SnackbarEvent
-import com.topjohnwu.superuser.Shell
 import kotlinx.coroutines.launch
 
 class SettingsViewModel : BaseViewModel(), BaseSettingsItem.Handler {
@@ -130,7 +130,8 @@ class SettingsViewModel : BaseViewModel(), BaseSettingsItem.Handler {
     }
 
     private fun createHosts() {
-        Shell.cmd("add_hosts_module").submit {
+        viewModelScope.launch {
+            RootUtils.addSystemlessHosts()
             AppContext.toast(R.string.settings_hosts_toast, Toast.LENGTH_SHORT)
         }
     }

app/core/src/main/aidl/com/topjohnwu/magisk/core/utils/IRootUtils.aidl

@@ -6,4 +6,5 @@ package com.topjohnwu.magisk.core.utils;
 interface IRootUtils {
     android.app.ActivityManager.RunningAppProcessInfo getAppProcess(int pid);
     IBinder getFileSystem();
+    boolean addSystemlessHosts();
 }

app/core/src/main/java/com/topjohnwu/magisk/core/ktx/XAndroid.kt

@@ -109,7 +109,7 @@ fun PackageManager.getPackageInfo(uid: Int, pid: Int): PackageInfo? {
             return null
         }
         // Try to find package name from PID
-        val proc = RootUtils.obj?.getAppProcess(pid)
+        val proc = RootUtils.getAppProcess(pid)
         if (proc == null) {
             if (uid == Process.SHELL_UID) {
                 // It is possible that some apps installed are sharing UID with shell.

app/core/src/main/java/com/topjohnwu/magisk/core/utils/RootUtils.kt

@@ -7,11 +7,14 @@ import android.content.ServiceConnection
 import android.os.IBinder
 import android.system.Os
 import androidx.core.content.getSystemService
+import com.topjohnwu.magisk.core.Const
 import com.topjohnwu.magisk.core.Info
 import com.topjohnwu.superuser.Shell
 import com.topjohnwu.superuser.ShellUtils
 import com.topjohnwu.superuser.ipc.RootService
 import com.topjohnwu.superuser.nio.FileSystemManager
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
 import timber.log.Timber
 import java.io.File
 import java.util.concurrent.locks.AbstractQueuedSynchronizer
@@ -43,16 +46,7 @@ class RootUtils(stub: Any?) : RootService() {
         return object : IRootUtils.Stub() {
             override fun getAppProcess(pid: Int) = safe(null) { getAppProcessImpl(pid) }
             override fun getFileSystem(): IBinder = FileSystemManager.getService()
-        }
-    }
-
-    private inline fun <T> safe(default: T, block: () -> T): T {
-        return try {
-            block()
-        } catch (e: Throwable) {
-            // The process died unexpectedly
-            Timber.e(e)
-            default
+            override fun addSystemlessHosts() = safe(false) { addSystemlessHostsImpl() }
         }
     }
 
@@ -78,6 +72,26 @@ class RootUtils(stub: Any?) : RootService() {
         return null
     }
 
+    private fun addSystemlessHostsImpl(): Boolean {
+        val module = File(Const.MODULE_PATH, "hosts")
+        if (module.exists()) return true
+        val hosts = File(module, "system/etc/hosts")
+        if (!hosts.parentFile.mkdirs()) return false
+        File(module, "module.prop").outputStream().writer().use {
+            it.write("""
+                id=hosts
+                name=Systemless Hosts
+                version=1.0
+                versionCode=1
+                author=Magisk
+                description=Magisk app built-in systemless hosts module
+            """.trimIndent())
+        }
+        File("/system/etc/hosts").copyTo(hosts)
+        File(module, "update").createNewFile()
+        return true
+    }
+
     object Connection : AbstractQueuedSynchronizer(), ServiceConnection {
         init {
             state = 1
@@ -131,11 +145,25 @@ class RootUtils(stub: Any?) : RootService() {
                 return field
             }
             private set
-        var obj: IRootUtils? = null
+        private var obj: IRootUtils? = null
             get() {
                 Connection.await()
                 return field
             }
-            private set
+
+        fun getAppProcess(pid: Int) = safe(null) { obj?.getAppProcess(pid) }
+
+        suspend fun addSystemlessHosts() =
+            withContext(Dispatchers.IO) { safe(false) { obj?.addSystemlessHosts() ?: false } }
+
+        private inline fun <T> safe(default: T, block: () -> T): T {
+            return try {
+                block()
+            } catch (e: Throwable) {
+                // The process died unexpectedly
+                Timber.e(e)
+                default
+            }
+        }
     }
 }

app/core/src/main/java/com/topjohnwu/magisk/test/Environment.kt

@@ -123,7 +123,9 @@ class Environment : BaseTest {
     }
 
     private fun setupSystemlessHost() {
-        assertTrue("hosts setup failed", Shell.cmd("add_hosts_module").exec().isSuccess)
+        val error = "hosts setup failed"
+        assertTrue(error, runBlocking { RootUtils.addSystemlessHosts() })
+        assertTrue(error, RootUtils.fs.getFile(Const.MODULE_PATH).getChildFile("hosts").exists())
     }
 
     private fun setupSepolicyRuleModule(root: ExtendedFile) {

scripts/app_functions.sh

@@ -118,24 +118,6 @@ EOF
   cd /
 }
 
-add_hosts_module() {
-  # Do not touch existing hosts module
-  [ -d /data/adb/modules/hosts ] && return
-  cd /data/adb/modules
-  mkdir -p hosts/system/etc
-  cat << EOF > hosts/module.prop
-id=hosts
-name=Systemless Hosts
-version=1.0
-versionCode=1
-author=Magisk
-description=Magisk app built-in systemless hosts module
-EOF
-  magisk --clone /system/etc/hosts hosts/system/etc/hosts
-  touch hosts/update
-  cd /
-}
-
 # $1 = APK
 # $2 = package name
 adb_pm_install() {