From 9de6e8846bf2cd46adcc20bde9934600cbc0a4a9 Mon Sep 17 00:00:00 2001
From: vvb2060 <vvb2060@gmail.com>
Date: Fri, 18 Mar 2022 04:04:13 +0800
Subject: [PATCH] Dump stub app to MAGISKTMP/stub.apk

---
 native/jni/core/bootstages.cpp | 18 ++++++++++++++----
 native/jni/init/init.cpp       |  2 +-
 native/jni/init/init.hpp       |  1 +
 native/jni/init/rootdir.cpp    |  4 ++++
 4 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/native/jni/core/bootstages.cpp b/native/jni/core/bootstages.cpp
index 7bfdf12d7..f1eca6a91 100644
--- a/native/jni/core/bootstages.cpp
+++ b/native/jni/core/bootstages.cpp
@@ -18,6 +18,7 @@
 using namespace std;
 
 static bool safe_mode = false;
+static int stub_fd = -1;
 bool zygisk_enabled = false;
 
 /*********
@@ -122,6 +123,10 @@ static bool magisk_env() {
 
     LOGI("* Initializing Magisk environment\n");
 
+    string stub_path = MAGISKTMP + "/stub.apk";
+    stub_fd = xopen(stub_path.data(), O_RDONLY | O_CLOEXEC);
+    unlink(stub_path.data());
+
     string pkg;
     get_manager(&pkg);
 
@@ -370,10 +375,15 @@ void boot_complete(int client) {
     if (access(SECURE_DIR, F_OK) != 0)
         xmkdir(SECURE_DIR, 0700);
 
-    if (!get_manager()) {
+    if (stub_fd > 0 && !get_manager()) {
         // Install stub
-        auto init = MAGISKTMP + "/magiskinit";
-        exec_command_sync(init.data(), "-x", "manager", "/data/magisk.apk");
-        install_apk("/data/magisk.apk");
+        struct stat st{};
+        fstat(stub_fd, &st);
+        int dfd = xopen("/data/stub.apk", O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0600);
+        xsendfile(dfd, stub_fd, nullptr, st.st_size);
+        close(stub_fd);
+        close(dfd);
+        stub_fd = -1;
+        install_apk("/data/stub.apk");
     }
 }
diff --git a/native/jni/init/init.cpp b/native/jni/init/init.cpp
index 940e57f76..e248f6c72 100644
--- a/native/jni/init/init.cpp
+++ b/native/jni/init/init.cpp
@@ -35,7 +35,7 @@ bool unxz(int fd, const uint8_t *buf, size_t size) {
     return true;
 }
 
-static int dump_manager(const char *path, mode_t mode) {
+int dump_manager(const char *path, mode_t mode) {
     int fd = xopen(path, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, mode);
     if (fd < 0)
         return 1;
diff --git a/native/jni/init/init.hpp b/native/jni/init/init.hpp
index d5e93c1b5..192bbc2f9 100644
--- a/native/jni/init/init.hpp
+++ b/native/jni/init/init.hpp
@@ -32,6 +32,7 @@ void load_kernel_info(BootConfig *config);
 bool check_two_stage();
 void setup_klog();
 const char *backup_init();
+int dump_manager(const char *path, mode_t mode);
 
 /***************
  * Base classes
diff --git a/native/jni/init/rootdir.cpp b/native/jni/init/rootdir.cpp
index ff1cb1ecf..d9e358cbd 100644
--- a/native/jni/init/rootdir.cpp
+++ b/native/jni/init/rootdir.cpp
@@ -233,6 +233,8 @@ void SARBase::patch_ro_root() {
         } else {
             xsymlink("./magisk32", "magisk");
         }
+
+        dump_manager("stub.apk", 0644);
     }
 
     if ((access(SPLIT_PLAT_CIL, F_OK) != 0 && access("/sepolicy", F_OK) == 0) || !hijack_sepolicy()) {
@@ -305,6 +307,8 @@ void MagiskInit::patch_rw_root() {
         } else {
             xsymlink("./magisk32", "magisk");
         }
+
+        dump_manager("stub.apk", 0644);
     }
 
     if ((!treble && access("/sepolicy", F_OK) == 0) || !hijack_sepolicy()) {