Significantly better AVD support

native/jni/core/bootstages.cpp

@@ -23,9 +23,9 @@ static bool safe_mode = false;
  * Setup *
  *********/
 
-#define MNT_DIR_IS(dir)   (me->mnt_dir == string_view(dir))
-#define SETMIR(b, part)   sprintf(b, "%s/" MIRRDIR "/" #part, MAGISKTMP.data())
-#define SETBLK(b, part)   sprintf(b, "%s/" BLOCKDIR "/" #part, MAGISKTMP.data())
+#define MNT_DIR_IS(dir) (me->mnt_dir == string_view(dir))
+#define SETMIR(b, part) snprintf(b, sizeof(b), "%s/" MIRRDIR "/" #part, MAGISKTMP.data())
+#define SETBLK(b, part) snprintf(b, sizeof(b), "%s/" BLOCKDIR "/" #part, MAGISKTMP.data())
 
 #define do_mount_mirror(part, flag) {\
     SETMIR(buf1, part); \

native/jni/core/daemon.cpp

@@ -91,6 +91,11 @@ static void handle_request_sync(int client, int code) {
     case START_DAEMON:
         setup_logfile(true);
         break;
+    case STOP_DAEMON:
+        magiskhide_handler(-1, nullptr);
+        write_int(client, 0);
+        // Terminate the daemon!
+        exit(0);
     }
 }
 
@@ -120,6 +125,7 @@ static void handle_request(int client) {
     case SQLITE_CMD:
     case GET_PATH:
     case MAGISKHIDE:
+    case STOP_DAEMON:
         if (!is_root) {
             write_int(client, ROOT_REQUIRED);
             goto done;

native/jni/core/magisk.cpp

@@ -28,6 +28,7 @@ Options:
 
 Advanced Options (Internal APIs):
    --daemon                  manually start magisk daemon
+   --stop                    remove all magisk changes and stop daemon
    --[init trigger]          start service for init trigger
                              Supported init triggers:
                              post-fs-data, service, boot-complete
@@ -84,6 +85,10 @@ int magisk_main(int argc, char *argv[]) {
         int fd = connect_daemon(true);
         write_int(fd, START_DAEMON);
         return 0;
+    } else if (argv[1] == "--stop"sv) {
+        int fd = connect_daemon();
+        write_int(fd, STOP_DAEMON);
+        return read_int(fd);
     } else if (argv[1] == "--post-fs-data"sv) {
         int fd = connect_daemon(true);
         write_int(fd, POST_FS_DATA);

native/jni/include/daemon.hpp

@@ -19,7 +19,8 @@ enum : int {
     CHECK_VERSION = SYNC_FLAG | 1,
     CHECK_VERSION_CODE = SYNC_FLAG | 2,
     GET_PATH = SYNC_FLAG | 3,
-    SUPERUSER = 4,
+    STOP_DAEMON = SYNC_FLAG | 4,
+    SUPERUSER = 5,
     POST_FS_DATA,
     LATE_START,
     BOOT_COMPLETE,

native/jni/magiskhide/hide_policy.cpp

@@ -25,14 +25,15 @@ void hide_daemon(int pid, int client) {
 #define TMPFS_MNT(dir) (mentry->mnt_type == "tmpfs"sv && str_starts(mentry->mnt_dir, "/" #dir))
 
 void hide_unmount(int pid) {
-    if (pid > 0 && switch_mnt_ns(pid))
-        return;
-
-    LOGD("hide: handling PID=[%d]\n", pid > 0 ? pid : getpid());
+    if (pid > 0) {
+        if (switch_mnt_ns(pid))
+            return;
+        LOGD("hide: handling PID=[%d]\n", pid);
+    }
 
     vector<string> targets;
 
-    // Unmount dummy skeletons and /sbin links
+    // Unmount dummy skeletons and MAGISKTMP
     targets.push_back(MAGISKTMP);
     parse_mnt("/proc/self/mounts", [&](mntent *mentry) {
         if (TMPFS_MNT(system) || TMPFS_MNT(vendor) || TMPFS_MNT(product) || TMPFS_MNT(system_ext))

native/jni/magiskhide/magiskhide.cpp

@@ -25,6 +25,11 @@ using namespace std;
 }
 
 void magiskhide_handler(int client, ucred *cred) {
+    if (client < 0) {
+        hide_unmount();
+        return;
+    }
+
     int req = read_int(client);
     int res = DAEMON_ERROR;
 

native/jni/utils/misc.hpp

@@ -126,7 +126,7 @@ int exec_command_sync(exec_t &exec, Args &&...args) {
 }
 template <class ...Args>
 int exec_command_sync(Args &&...args) {
-    exec_t exec{};
+    exec_t exec;
     return exec_command_sync(exec, args...);
 }
 template <class ...Args>

scripts/emulator.sh

@@ -3,16 +3,19 @@
 #   AVD Magisk Setup
 #####################################################################
 #
-# This script will setup an environment with minimal Magisk that
-# the Magisk app will be happy to run properly within the official
-# emulator bundled with Android Studio (AVD).
+# Support emulator ABI: x86_64 *only*
+# Support API level: 23 - 31 (21 and 22 images do not have SELinux)
 #
-# ONLY use this script for developing the Magisk app or root apps
-# in the emulator. The constructed Magisk environment is not a
-# fully functional one as if it is running on an actual device.
+# This script will stop zygote, simulate the Magisk start up process
+# that would've happened before zygote was started, and finally
+# restart zygote. This is useful for setting up the emulator for
+# developing Magisk, testing modules, and developing root apps using
+# the official Android emulator (AVD) instead of a real device.
 #
-# The script assumes you are using x64 emulator images.
-# Build binaries with `./build.py binary` before running this script.
+# This only covers the "core" features of Magisk. Testing magiskinit
+# and magiskboot require additional setups that are not covered here.
+#
+# Build everything by `./build.py all` before running this script.
 #
 #####################################################################
 
@@ -29,16 +32,13 @@ mount_sbin() {
 if [ ! -f /system/build.prop ]; then
   # Running on PC
   cd "$(dirname "$0")/.."
-  adb push native/out/x86_64/busybox native/out/x86_64/magiskinit \
-  native/out/x86_64/magisk scripts/emulator.sh /data/local/tmp
+  adb push native/out/x86_64/busybox out/app-debug.apk scripts/emulator.sh /data/local/tmp
   adb shell sh /data/local/tmp/emulator.sh
   exit 0
 fi
 
 cd /data/local/tmp
-chmod 777 busybox
-chmod 777 magiskinit
-chmod 777 magisk
+chmod 755 busybox
 
 if [ -z "$FIRST_STAGE" ]; then
   export FIRST_STAGE=1
@@ -52,20 +52,34 @@ if [ -z "$FIRST_STAGE" ]; then
   fi
 fi
 
-# Remove previous setup if exist
-pgrep magiskd >/dev/null && pkill -9 magiskd
-[ -f /sbin/magisk ] && umount -l /sbin
-[ -f /system/bin/magisk ] && umount -l /system/bin
-if [ -d /dev/magisk ]; then
-  umount -l /dev/magisk 2>/dev/null
-  rm -rf /dev/magisk
+pm install -r $(pwd)/app-debug.apk
+
+# Extract files from APK
+unzip -oj app-debug.apk 'lib/x86_64/*' 'lib/x86/libmagisk32.so' -x 'lib/x86_64/busybox.so'
+for file in lib*.so; do
+  chmod 755 $file
+  mv "$file" "${file:3:${#file}-6}"
+done
+
+# Stop zygote (and previous setup if exists)
+magisk --stop 2>/dev/null
+stop
+if [ -d /dev/avd-magisk ]; then
+  umount -l /dev/avd-magisk 2>/dev/null
+  rm -rf /dev/avd-magisk 2>/dev/null
 fi
 
 # SELinux stuffs
 ln -sf ./magiskinit magiskpolicy
-./magiskpolicy --live --magisk
+if [ -f /vendor/etc/selinux/precompiled_sepolicy ]; then
+  ./magiskpolicy --load /vendor/etc/selinux/precompiled_sepolicy --live --magisk
+elif [ -f /sepolicy ]; then
+  ./magiskpolicy --load /sepolicy --live --magisk
+else
+  ./magiskpolicy --live --magisk
+fi
 
-BINDIR=/sbin
+MAGISKTMP=/sbin
 
 # Setup bin overlay
 if mount | grep -q rootfs; then
@@ -81,13 +95,11 @@ if mount | grep -q rootfs; then
 elif [ -e /sbin ]; then
   # Legacy SAR
   mount_sbin
-  if ! grep -q '/sbin/.magisk/mirror/system_root' /proc/mounts; then
-    mkdir -p /sbin/.magisk/mirror/system_root
-    block=$(mount | grep ' / ' | awk '{ print $1 }')
-    [ $block = "/dev/root" ] && block=/dev/block/dm-0
-    mount -o ro $block /sbin/.magisk/mirror/system_root
-  fi
-  for file in /sbin/.magisk/mirror/system_root/sbin/*; do
+  mkdir -p /dev/sysroot
+  block=$(mount | grep ' / ' | awk '{ print $1 }')
+  [ $block = "/dev/root" ] && block=/dev/block/dm-0
+  mount -o ro $block /dev/sysroot
+  for file in /dev/sysroot/sbin/*; do
     [ ! -e $file ] && break
     if [ -L $file ]; then
       cp -af $file /sbin
@@ -97,25 +109,43 @@ elif [ -e /sbin ]; then
       mount -o bind $file $sfile
     fi
   done
+  umount -l /dev/sysroot
+  rm -rf /dev/sysroot
 else
-  # Android Q+ without sbin, use overlayfs
-  BINDIR=/dev/magisk/upper
-  mkdir /dev/magisk
-  mount -t tmpfs -o 'mode=0755' tmpfs /dev/magisk
-  chcon u:object_r:system_file:s0 /dev/magisk
-  mkdir /dev/magisk/upper
-  mkdir /dev/magisk/work
-  ./magisk --clone-attr /system/bin /dev/magisk/upper
-  mount -t overlay overlay -o lowerdir=/system/bin,upperdir=/dev/magisk/upper,workdir=/dev/magisk/work /system/bin
+  # Android Q+ without sbin
+  MAGISKTMP=/dev/avd-magisk
+  mkdir /dev/avd-magisk
+  mount -t tmpfs -o 'mode=0755' tmpfs /dev/avd-magisk
 fi
 
 # Magisk stuffs
-cp -af ./magisk $BINDIR/magisk
-chmod 755 $BINDIR/magisk
-ln -s ./magisk $BINDIR/su
-ln -s ./magisk $BINDIR/resetprop
-ln -s ./magisk $BINDIR/magiskhide
-mkdir -p /data/adb/modules 2>/dev/null
+mkdir -p /data/adb/magisk 2>/dev/null
+unzip -oj app-debug.apk 'assets/*' -x 'assets/chromeos/*' -d /data/adb/magisk
+mkdir /data/adb/modules 2>/dev/null
 mkdir /data/adb/post-fs-data.d 2>/dev/null
 mkdir /data/adb/services.d 2>/dev/null
-$BINDIR/magisk --daemon
+
+for file in magisk32 magisk64 magiskinit; do
+  chmod 755 ./$file
+  cp -af ./$file $MAGISKTMP/$file
+  cp -af ./$file /data/adb/magisk/$file
+done
+cp -af ./magiskboot /data/adb/magisk/magiskboot
+cp -af ./busybox /data/adb/magisk/busybox
+
+ln -s ./magisk64 $MAGISKTMP/magisk
+ln -s ./magisk $MAGISKTMP/su
+ln -s ./magisk $MAGISKTMP/resetprop
+ln -s ./magisk $MAGISKTMP/magiskhide
+ln -s ./magiskinit $MAGISKTMP/magiskpolicy
+
+mkdir -p $MAGISKTMP/.magisk/mirror
+mkdir $MAGISKTMP/.magisk/block
+touch $MAGISKTMP/.magisk/config
+
+# Boot up
+$MAGISKTMP/magisk --post-fs-data
+while [ ! -f /dev/.magisk_unblock ]; do sleep 1; done
+rm /dev/.magisk_unblock
+start
+$MAGISKTMP/magisk --service