Add new build command avd_patch

build.py

@@ -383,24 +383,6 @@ def build_stub(args):
     build_apk(args, 'stub')
 
 
-def build_snet(args):
-    if not op.exists(op.join('stub', 'src', 'main', 'java', 'com', 'topjohnwu', 'snet')):
-        error('snet sources have to be bind mounted on top of the stub folder')
-    header('* Building snet extension')
-    proc = execv([gradlew, 'stub:assembleRelease'])
-    if proc.returncode != 0:
-        error('Build snet extention failed!')
-    source = op.join('stub', 'build', 'outputs', 'apk',
-                     'release', 'stub-release.apk')
-    target = op.join(config['outdir'], 'snet.jar')
-    # Extract classes.dex
-    with zipfile.ZipFile(target, 'w', compression=zipfile.ZIP_DEFLATED, allowZip64=False) as zout:
-        with zipfile.ZipFile(source) as zin:
-            zout.writestr('classes.dex', zin.read('classes.dex'))
-    rm(source)
-    header('Output: ' + target)
-
-
 def cleanup(args):
     support_targets = {'native', 'java'}
     if args.target:
@@ -470,13 +452,54 @@ def setup_avd(args):
 
     abi = cmd_out([adb_path, 'shell', 'getprop', 'ro.product.cpu.abi'])
     proc = execv([adb_path, 'push', f'native/out/{abi}/busybox', 'out/app-debug.apk',
-           'scripts/emulator.sh', '/data/local/tmp'])
+           'scripts/avd_magisk.sh', '/data/local/tmp'])
     if proc.returncode != 0:
         error('adb push failed!')
 
-    proc = execv([adb_path, 'shell', 'sh', '/data/local/tmp/emulator.sh'])
+    proc = execv([adb_path, 'shell', 'sh', '/data/local/tmp/avd_magisk.sh'])
     if proc.returncode != 0:
-        error('emulator.sh failed!')
+        error('avd_magisk.sh failed!')
+
+
+def patch_avd_ramdisk(args):
+    build_binary(args)
+    build_app(args)
+
+    header('* Patching emulator ramdisk.img')
+
+    # Create a backup to prevent accidental overwrites
+    backup = args.ramdisk + '.bak'
+    if not op.exists(backup):
+        cp(args.ramdisk, backup)
+
+    ini = op.join(op.dirname(args.ramdisk), 'advancedFeatures.ini')
+    with open(ini, 'r') as f:
+        adv_ft = f.read()
+
+    # Need to turn off system as root
+    if 'SystemAsRoot = on' in adv_ft:
+        # Create a backup
+        cp(ini, ini + '.bak')
+        adv_ft = adv_ft.replace('SystemAsRoot = on', 'SystemAsRoot = off')
+        with open(ini, 'w') as f:
+            f.write(adv_ft)
+
+    abi = cmd_out([adb_path, 'shell', 'getprop', 'ro.product.cpu.abi'])
+    proc = execv([adb_path, 'push', f'native/out/{abi}/busybox', 'out/app-debug.apk',
+           'scripts/avd_patch.sh', '/data/local/tmp'])
+    if proc.returncode != 0:
+        error('adb push failed!')
+    proc = execv([adb_path, 'push', backup, '/data/local/tmp/ramdisk.cpio.gz'])
+    if proc.returncode != 0:
+        error('adb push failed!')
+
+    proc = execv([adb_path, 'shell', 'sh', '/data/local/tmp/avd_patch.sh'])
+    if proc.returncode != 0:
+        error('avd_patch.sh failed!')
+
+    proc = execv([adb_path, 'pull', '/data/local/tmp/ramdisk.cpio.gz', args.ramdisk])
+    if proc.returncode != 0:
+        error('adb pull failed!')
 
 
 def build_all(args):
@@ -512,13 +535,13 @@ stub_parser = subparsers.add_parser('stub', help='build the stub app')
 stub_parser.set_defaults(func=build_stub)
 
 avd_parser = subparsers.add_parser(
-    'emulator', help='build and setup AVD for development')
+    'emulator', help='setup AVD for development')
 avd_parser.set_defaults(func=setup_avd)
 
-# Need to bind mount snet sources on top of stub folder
-# Note: source code for the snet extension is *NOT* public
-snet_parser = subparsers.add_parser('snet', help='build snet extension')
-snet_parser.set_defaults(func=build_snet)
+avd_patch_parser = subparsers.add_parser(
+    'avd_patch', help='patch AVD ramdisk.img')
+avd_patch_parser.add_argument('ramdisk', help='path to ramdisk.img')
+avd_patch_parser.set_defaults(func=patch_avd_ramdisk)
 
 clean_parser = subparsers.add_parser('clean', help='cleanup')
 clean_parser.add_argument(

native/jni/init/getinfo.cpp

@@ -180,6 +180,8 @@ void BootConfig::set(const kv_pairs &kv) {
             strlcpy(hardware_plat, value.data(), sizeof(hardware_plat));
         } else if (key == "androidboot.fstab_suffix") {
             strlcpy(fstab_suffix, value.data(), sizeof(fstab_suffix));
+        } else if (key == "qemu") {
+            emulator = true;
         }
     }
 }
@@ -193,6 +195,7 @@ void BootConfig::print() {
     LOGD("fstab_suffix=[%s]\n", fstab_suffix);
     LOGD("hardware=[%s]\n", hardware);
     LOGD("hardware.platform=[%s]\n", hardware_plat);
+    LOGD("emulator=[%d]\n", emulator);
 }
 
 #define read_dt(name, key)                                          \
@@ -230,7 +233,7 @@ void load_kernel_info(BootConfig *config) {
     parse_prop_file("/.backup/.magisk", [=](auto key, auto value) -> bool {
         if (key == "RECOVERYMODE" && value == "true") {
             LOGD("Running in recovery mode, waiting for key...\n");
-            config->skip_initramfs = !check_key_combo();
+            config->skip_initramfs = config->emulator || !check_key_combo();
             return false;
         }
         return true;

native/jni/init/init.hpp

@@ -6,6 +6,7 @@ struct BootConfig {
     bool skip_initramfs;
     bool force_normal_boot;
     bool rootwait;
+    bool emulator;
     char slot[3];
     char dt_dir[64];
     char fstab_suffix[32];
@@ -66,6 +67,10 @@ protected:
     mmap_data magisk_config;
     std::string custom_rules_dir;
 
+    // When this boolean is set, this means we are currently
+    // running magiskinit on legacy SAR AVD emulator
+    bool avd_hack = false;
+
     void mount_with_dt();
     bool patch_sepolicy(const char *file);
     void setup_tmp(const char *path);

native/jni/init/mount.cpp

@@ -158,12 +158,19 @@ void MagiskInit::mount_with_dt() {
     for (const auto &entry : fstab) {
         if (is_lnk(entry.mnt_point.data()))
             continue;
+        // When we force AVD to disable SystemAsRoot, it will always add system
+        // to dt fstab, which we actually have already mounted as root
+        if (avd_hack && entry.mnt_point == "/system")
+            continue;
         // Derive partname from dev
         sprintf(blk_info.partname, "%s%s", basename(entry.dev.data()), config->slot);
         setup_block(true);
         xmkdir(entry.mnt_point.data(), 0755);
         xmount(blk_info.block_dev, entry.mnt_point.data(), entry.type.data(), MS_RDONLY, nullptr);
-        mount_list.push_back(entry.mnt_point);
+        // When avd_hack is true, do not add any early mount partitions to mount_list
+        // as we will actually forcefully disable original init's early mount
+        if (!avd_hack)
+            mount_list.push_back(entry.mnt_point);
     }
 }
 
@@ -372,6 +379,7 @@ void SARInit::early_mount() {
         xmkdir("/dev", 0755);
         xmount("tmpfs", "/dev", "tmpfs", 0, "mode=755");
         mount_list.emplace_back("/dev");
+        avd_hack = config->emulator;
         mount_with_dt();
     }
 }
@@ -399,7 +407,7 @@ bool SecondStageInit::prepare() {
 void BaseInit::exec_init() {
     // Unmount in reverse order
     for (auto &p : reversed(mount_list)) {
-        if (xumount(p.data()) == 0)
+        if (xumount2(p.data(), MNT_DETACH) == 0)
             LOGD("Unmount [%s]\n", p.data());
     }
     execv("/init", argv);

native/jni/init/rootdir.cpp

@@ -234,6 +234,10 @@ void SARBase::patch_rootdir() {
             make_pair(SPLIT_PLAT_CIL, "xxx"), /* Force loading monolithic sepolicy */
             make_pair(MONOPOLICY, sepol)      /* Redirect /sepolicy to custom path */
          });
+        if (avd_hack) {
+            // Force disable early mount on original init
+            init.patch({ make_pair("android,fstab", "xxx") });
+        }
         xmkdir(ROOTOVL, 0);
         int dest = xopen(ROOTOVL "/init", O_CREAT | O_WRONLY | O_CLOEXEC, 0);
         xwrite(dest, init.buf, init.sz);

scripts/avd_magisk.sh

@@ -6,14 +6,17 @@
 # Support emulator ABI: x86_64 and arm64
 # Support API level: 23 - 31 (21 and 22 images do not have SELinux)
 #
+# With an emulator booted and accessible via ADB, usage:
+# ./build.py emulator
+#
 # 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.
 #
-# This only covers the "core" features of Magisk. Testing magiskinit
-# and magiskboot require additional setups that are not covered here.
+# This only covers the "core" features of Magisk. For testing
+# magiskinit, please checkout avd_init.sh.
 #
 #####################################################################
 

scripts/avd_patch.sh

@@ -0,0 +1,81 @@
+#!/usr/bin/env bash
+#####################################################################
+#   AVD MagiskInit Setup
+#####################################################################
+#
+# Support emulator ABI: x86_64 and arm64
+# Support API level: 23 - 31 (21 and 22 images do not have SELinux)
+#
+# With an emulator booted and accessible via ADB, usage:
+# ./build.py avd_patch path/to/booted/avd-image/ramdisk.img
+#
+# The purpose of this script is to patch AVD ramdisk.img and do a
+# full integration test of magiskinit under several circumstances.
+# After patching ramdisk.img, close the emulator, then select
+# "Cold Boot Now" in AVD Manager to force a full reboot.
+#
+#####################################################################
+# AVD Init Configurations:
+#
+# rootfs w/o early mount: API 23 - 25
+# rootfs with early mount: API 26 - 27
+# Legacy system-as-root: API 28
+# 2 stage init: API 29 - 31
+#####################################################################
+
+if [ ! -f /system/build.prop ]; then
+  # Running on PC
+  echo 'Please run `./build.py avd_patch` instead of directly executing the script!'
+  exit 1
+fi
+
+cd /data/local/tmp
+chmod 755 busybox
+
+if [ -z "$FIRST_STAGE" ]; then
+  export FIRST_STAGE=1
+  export ASH_STANDALONE=1
+  # Re-exec script with busybox
+  exec ./busybox sh $0
+fi
+
+# Extract files from APK
+unzip -oj app-debug.apk 'assets/util_functions.sh'
+. ./util_functions.sh
+
+api_level_arch_detect
+
+unzip -oj app-debug.apk "lib/$ABI/*" "lib/$ABI32/libmagisk32.so" -x "lib/$ABI/busybox.so"
+for file in lib*.so; do
+  chmod 755 $file
+  mv "$file" "${file:3:${#file}-6}"
+done
+
+gzip -d ramdisk.cpio.gz
+cp ramdisk.cpio ramdisk.cpio.orig
+
+touch config
+
+# For API 28, we also patch advancedFeatures.ini to disable SAR
+# Manually override skip_initramfs by setting RECOVERYMODE=true
+[ $API = "28" ] && echo 'RECOVERYMODE=true' >> config
+
+./magiskboot compress=xz magisk32 magisk32.xz
+./magiskboot compress=xz magisk64 magisk64.xz
+
+export KEEPVERITY=false
+export KEEPFORCEENCRYPT=true
+
+./magiskboot cpio ramdisk.cpio \
+"add 0750 init magiskinit" \
+"mkdir 0750 overlay.d" \
+"mkdir 0750 overlay.d/sbin" \
+"add 0644 overlay.d/sbin/magisk32.xz magisk32.xz" \
+"add 0644 overlay.d/sbin/magisk64.xz magisk64.xz" \
+"patch" \
+"backup ramdisk.cpio.orig" \
+"mkdir 000 .backup" \
+"add 000 .backup/.magisk config"
+
+rm -f ramdisk.cpio.orig config magisk*.xz
+gzip -9 ramdisk.cpio