Move worker mount to magiskinit

Author: yujincheng08

native/src/core/lib.rs

@@ -9,7 +9,7 @@ use daemon::{daemon_entry, find_apk_path, get_magiskd, MagiskD};
 use logging::{
     android_logging, magisk_logging, zygisk_close_logd, zygisk_get_logd, zygisk_logging,
 };
-use mount::{find_preinit_device, revert_unmount, setup_mounts};
+use mount::{find_preinit_device, revert_unmount, setup_mounts, clean_mounts};
 use resetprop::{persist_delete_prop, persist_get_prop, persist_get_props, persist_set_prop};
 
 mod cert;
@@ -92,6 +92,7 @@ pub mod ffi {
         fn find_apk_path(pkg: Utf8CStrRef, data: &mut [u8]) -> usize;
         fn read_certificate(fd: i32, version: i32) -> Vec<u8>;
         fn setup_mounts();
+        fn clean_mounts();
         fn find_preinit_device() -> String;
         fn revert_unmount(pid: i32);
         unsafe fn persist_get_prop(name: Utf8CStrRef, prop_cb: Pin<&mut PropCb>);

native/src/core/module.cpp

@@ -157,11 +157,9 @@ void tmpfs_node::mount() {
     if (!isa<tmpfs_node>(parent())) {
         auto worker_dir = worker_path();
         mkdirs(worker_dir.data(), 0);
-        bind_mount("tmpfs", worker_dir.data(), worker_dir.data());
         clone_attr(exist() ? node_path().data() : parent()->node_path().data(), worker_dir.data());
         dir_node::mount();
-        VLOGD(replace() ? "replace" : "move", worker_dir.data(), node_path().data());
-        xmount(worker_dir.data(), node_path().data(), nullptr, MS_MOVE, nullptr);
+        bind_mount(replace() ? "replace" : "move", worker_dir.data(), node_path().data());
         xmount(nullptr, node_path().data(), nullptr, MS_REMOUNT | MS_BIND | MS_RDONLY, nullptr);
     } else {
         const string dest = worker_path();
@@ -333,10 +331,7 @@ void load_modules() {
     }
 
     // cleanup mounts
-    ssprintf(buf, sizeof(buf), "%s/" WORKERDIR, get_magisk_tmp());
-    xumount2(buf, MNT_DETACH);
-    ssprintf(buf, sizeof(buf), "%s/" MODULEMNT, get_magisk_tmp());
-    xumount2(buf, MNT_DETACH);
+    clean_mounts();
 }
 
 /************************

native/src/core/mount.rs

@@ -94,36 +94,40 @@ pub fn setup_mounts() {
                 ptr::null(),
             )
             .as_os_err()?;
-            libc::mount(
-                ptr::null(),
+        }
+    };
+}
+
+pub fn clean_mounts() {
+    let magisk_tmp = get_magisk_tmp();
+
+    let mut buf = Utf8CStrBufArr::default();
+
+    let module_mnt = FsPathBuf::new(&mut buf).join(magisk_tmp).join(MODULEMNT);
+    let _: LoggedResult<()> = try {
+        unsafe {
+            libc::umount2(
                 module_mnt.as_ptr(),
-                ptr::null(),
-                libc::MS_PRIVATE,
-                ptr::null(),
+                libc::MNT_DETACH,
             )
             .as_os_err()?;
         }
     };
 
-    // Prepare worker
     let worker_dir = FsPathBuf::new(&mut buf).join(magisk_tmp).join(WORKERDIR);
     let _: LoggedResult<()> = try {
-        worker_dir.mkdir(0)?;
         unsafe {
             libc::mount(
-                worker_dir.as_ptr(),
+                ptr::null(),
                 worker_dir.as_ptr(),
                 ptr::null(),
-                libc::MS_BIND,
+                libc::MS_PRIVATE | libc::MS_REC,
                 ptr::null(),
             )
             .as_os_err()?;
-            libc::mount(
-                ptr::null(),
+            libc::umount2(
                 worker_dir.as_ptr(),
-                ptr::null(),
-                libc::MS_PRIVATE,
-                ptr::null(),
+                libc::MNT_DETACH,
             )
             .as_os_err()?;
         }

native/src/init/mount.cpp

@@ -236,6 +236,7 @@ void MagiskInit::setup_tmp(const char *path) {
 
     xmkdir(INTLROOT, 0711);
     xmkdir(DEVICEDIR, 0711);
+    xmkdir(WORKERDIR, 0);
 
     mount_preinit_dir(preinit_dev);
 
@@ -251,6 +252,9 @@ void MagiskInit::setup_tmp(const char *path) {
 
     chdir(path);
 
+    // Prepare worker
+    xmount(WORKERDIR, WORKERDIR, nullptr, MS_BIND, nullptr);
+
     // Use isolated devpts if kernel support
     if (access("/dev/pts/ptmx", F_OK) == 0) {
         xmkdirs(SHELLPTS, 0755);