Migrate magiskinit selinux.cpp to Rust

native/src/Android.mk

@@ -66,7 +66,6 @@ LOCAL_SRC_FILES := \
     init/mount.cpp \
     init/rootdir.cpp \
     init/getinfo.cpp \
-    init/selinux.cpp \
     init/init-rs.cpp
 
 LOCAL_LDFLAGS := -static

native/src/base/cstr.rs

@@ -1,4 +1,4 @@
-use cxx::{type_id, ExternType};
+use cxx::{ExternType, type_id};
 use libc::c_char;
 use std::borrow::Borrow;
 use std::cmp::min;
@@ -479,6 +479,11 @@ impl FsPath {
         unsafe { mem::transmute(value.as_ref()) }
     }
 
+    #[inline(always)]
+    pub const fn from_utfcstr(value: &Utf8CStr) -> &FsPath {
+        unsafe { mem::transmute(value) }
+    }
+
     #[inline(always)]
     pub fn from_mut<T: AsMut<Utf8CStr> + ?Sized>(value: &mut T) -> &mut FsPath {
         unsafe { mem::transmute(value.as_mut()) }
@@ -781,14 +786,10 @@ macro_rules! cstr {
 
 #[macro_export]
 macro_rules! raw_cstr {
-    ($str:expr) => {{
-        $crate::cstr!($str).as_ptr()
-    }};
+    ($str:expr) => {{ $crate::cstr!($str).as_ptr() }};
 }
 
 #[macro_export]
 macro_rules! path {
-    ($str:expr) => {{
-        $crate::FsPath::from($crate::cstr!($str))
-    }};
+    ($str:expr) => {{ $crate::FsPath::from_utfcstr($crate::cstr!($str)) }};
 }

native/src/base/files.rs

@@ -199,7 +199,7 @@ impl FsPath {
     }
 
     pub fn create(&self, flags: i32, mode: mode_t) -> io::Result<File> {
-        Ok(File::from(open_fd!(self, flags, mode)?))
+        Ok(File::from(open_fd!(self, O_CREAT | flags, mode)?))
     }
 
     pub fn exists(&self) -> bool {
@@ -431,6 +431,10 @@ impl FsPath {
     pub fn create_symlink_to(&self, target: &FsPath) -> io::Result<()> {
         unsafe { libc::symlink(target.as_ptr(), self.as_ptr()).as_os_err() }
     }
+
+    pub fn mkfifo(&self, mode: mode_t) -> io::Result<()> {
+        unsafe { libc::mkfifo(self.as_ptr(), mode).as_os_err() }
+    }
 }
 
 impl FsPathFollow {

native/src/base/mount.rs

@@ -1,4 +1,4 @@
-use crate::{FsPath, LibcReturn};
+use crate::{FsPath, LibcReturn, Utf8CStr};
 use libc::c_ulong;
 use std::ptr;
 
@@ -29,6 +29,19 @@ impl FsPath {
         }
     }
 
+    pub fn remount_with_data(&self, data: &Utf8CStr) -> std::io::Result<()> {
+        unsafe {
+            libc::mount(
+                ptr::null(),
+                self.as_ptr(),
+                ptr::null(),
+                libc::MS_REMOUNT,
+                data.as_ptr().cast(),
+            )
+            .as_os_err()
+        }
+    }
+
     pub fn move_mount_to(&self, path: &FsPath) -> std::io::Result<()> {
         unsafe {
             libc::mount(

native/src/include/consts.rs

@@ -27,3 +27,4 @@ pub const DEVICEDIR: &str = concatcp!(INTERNAL_DIR, "/device");
 pub const PREINITDEV: &str = concatcp!(DEVICEDIR, "/preinit");
 pub const ROOTOVL: &str = concatcp!(INTERNAL_DIR, "/rootdir");
 pub const ROOTMNT: &str = concatcp!(ROOTOVL, "/.mount_list");
+pub const SELINUXMOCK: &str = concatcp!(INTERNAL_DIR, "/selinux");

native/src/init/init.hpp

@@ -11,10 +11,30 @@
 
 #include <base.hpp>
 #include <stream.hpp>
+#include <sepolicy.hpp>
 
 #include "init-rs.hpp"
 
 int magisk_proxy_main(int, char *argv[]);
 rust::Utf8CStr backup_init();
 
+// Expose some constants to Rust
+
+static inline rust::Utf8CStr split_plat_cil() {
+    return SPLIT_PLAT_CIL;
+};
+
+static inline rust::Utf8CStr preload_lib() {
+    return PRELOAD_LIB;
+}
+
+static inline rust::Utf8CStr preload_policy() {
+    return PRELOAD_POLICY;
+}
+
+static inline rust::Utf8CStr preload_ack() {
+    return PRELOAD_ACK;
+}
+
+
 #endif

native/src/init/lib.rs

@@ -3,11 +3,12 @@
 #![feature(try_blocks)]
 #![allow(clippy::missing_safety_doc)]
 
+use base::FsPath;
 use logging::setup_klog;
 // Has to be pub so all symbols in that crate is included
 pub use magiskpolicy;
 use mount::{is_device_mounted, switch_root};
-use rootdir::{inject_magisk_rc, OverlayAttr};
+use rootdir::{OverlayAttr, inject_magisk_rc};
 
 #[path = "../include/consts.rs"]
 mod consts;
@@ -16,6 +17,7 @@ mod init;
 mod logging;
 mod mount;
 mod rootdir;
+mod selinux;
 mod twostage;
 
 #[cxx::bridge]
@@ -56,6 +58,12 @@ pub mod ffi {
 
         unsafe fn magisk_proxy_main(argc: i32, argv: *mut *mut c_char) -> i32;
         fn backup_init() -> Utf8CStrRef<'static>;
+
+        // Constants
+        fn split_plat_cil() -> Utf8CStrRef<'static>;
+        fn preload_lib() -> Utf8CStrRef<'static>;
+        fn preload_policy() -> Utf8CStrRef<'static>;
+        fn preload_ack() -> Utf8CStrRef<'static>;
     }
 
     #[namespace = "rust"]
@@ -81,6 +89,7 @@ pub mod ffi {
         type OverlayAttr;
         fn parse_config_file(self: &mut MagiskInit);
         fn mount_overlay(self: &mut MagiskInit, dest: Utf8CStrRef);
+        fn handle_sepolicy(self: &mut MagiskInit);
         fn restore_overlay_contexts(self: &MagiskInit);
     }
     unsafe extern "C++" {
@@ -94,7 +103,21 @@ pub mod ffi {
         fn collect_devices(self: &MagiskInit);
         fn mount_preinit_dir(self: &MagiskInit);
         unsafe fn find_block(self: &MagiskInit, partname: *const c_char) -> u64;
-        fn handle_sepolicy(self: &mut MagiskInit);
         unsafe fn patch_fissiond(self: &mut MagiskInit, tmp_path: *const c_char);
     }
 }
+
+#[inline(always)]
+fn preload_lib() -> &'static FsPath {
+    FsPath::from(ffi::preload_lib())
+}
+
+#[inline(always)]
+fn preload_policy() -> &'static FsPath {
+    FsPath::from(ffi::preload_policy())
+}
+
+#[inline(always)]
+fn preload_ack() -> &'static FsPath {
+    FsPath::from(ffi::preload_ack())
+}