Move MagiskInit::exec_init to rust

native/src/init/lib.rs

@@ -55,9 +55,10 @@ pub mod ffi {
         fn reset_overlay_contexts();
         unsafe fn start_magisk_init(argv: *mut *mut c_char);
     }
-    
+
     extern "Rust" {
         fn prepare_data(self: &MagiskInit);
+        fn exec_init(self: &MagiskInit);
     }
 
     unsafe extern "C++" {
@@ -90,7 +91,6 @@ pub mod ffi {
         // SELinux
         unsafe fn patch_sepolicy(self: &MagiskInit, in_: *const c_char, out: *const c_char);
         fn hijack_sepolicy(self: &mut MagiskInit) -> bool;
-        fn exec_init(self: &MagiskInit);
         fn legacy_system_as_root(self: &mut MagiskInit);
         fn rootfs(self: &mut MagiskInit);
         fn start(self: &mut MagiskInit);

native/src/init/mount.cpp

@@ -210,17 +210,6 @@ mount_root:
     return is_two_stage;
 }
 
-void MagiskInit::exec_init() const noexcept {
-    // Unmount in reverse order
-    for (auto i = mount_list.size(); i > 0; --i) {
-        auto &p = mount_list[i - 1];
-        if (xumount2(p.data(), MNT_DETACH) == 0)
-            LOGD("Unmount [%s]\n", p.data());
-    }
-    execve("/init", argv, environ);
-    exit(1);
-}
-
 void MagiskInit::setup_tmp(const char *path) const noexcept {
     LOGD("Setup Magisk tmp at %s\n", path);
     chdir("/data");

native/src/init/mount.rs

@@ -1,3 +1,4 @@
+use cxx::CxxString;
 use std::{
     collections::BTreeSet,
     ops::Bound::{Excluded, Unbounded},
@@ -5,15 +6,18 @@ use std::{
     ptr::null as nullptr,
 };
 
-use cxx::CxxString;
-
 use crate::ffi::MagiskInit;
 use base::{
-    cstr, debug,
-    libc::{chdir, chroot, mount, MS_MOVE},
-    parse_mount_info, raw_cstr, Directory, FsPath, LibcReturn, LoggedResult, StringExt, Utf8CStr,
+    cstr, debug, libc,
+    libc::{chdir, chroot, execve, exit, mount, umount2, MNT_DETACH, MS_MOVE},
+    parse_mount_info, raw_cstr, Directory, FsPath, LibcReturn, LoggedResult, ResultExt, StringExt,
+    Utf8CStr,
 };
 
+extern "C" {
+    static environ: *const *mut libc::c_char;
+}
+
 pub fn switch_root(path: &Utf8CStr) {
     let res: LoggedResult<()> = try {
         debug!("Switch root to {}", path);
@@ -94,4 +98,23 @@ impl MagiskInit {
         }
         inner().ok();
     }
+
+    pub(crate) fn exec_init(&self) {
+        unsafe {
+            for p in self.mount_list.iter().rev() {
+                if umount2(p.as_ptr().cast(), MNT_DETACH)
+                    .as_os_err()
+                    .log()
+                    .is_ok()
+                {
+                    debug!("Unmount [{}]", p);
+                }
+            }
+            execve(raw_cstr!("/init"), self.argv.cast(), environ.cast())
+                .as_os_err()
+                .log()
+                .ok();
+            exit(1);
+        }
+    }
 }