Refactor to better support Magisk

zygiskd/src/dl.rs

@@ -76,7 +76,7 @@ pub unsafe fn dlopen(path: &str, flags: i32) -> Result<*mut c_void> {
     let result = android_dlopen_ext(filename, flags, &info);
     if result.is_null() {
         let e = std::ffi::CStr::from_ptr(libc::dlerror()).to_string_lossy();
-        bail!("dlopen failed: {}", e);
+        bail!(e);
     }
     Ok(result)
 }

zygiskd/src/utils.rs

@@ -1,6 +1,7 @@
 use anyhow::Result;
 use nix::unistd::gettid;
 use std::{fs, io::{Read, Write}, os::unix::net::UnixStream, process::Command};
+use std::ffi::c_char;
 use std::os::fd::FromRawFd;
 use std::os::unix::net::UnixListener;
 use nix::sys::socket::{AddressFamily, SockFlag, SockType, UnixAddr};
@@ -37,6 +38,24 @@ pub fn get_native_bridge() -> String {
     std::env::var("NATIVE_BRIDGE").unwrap_or_default()
 }
 
+pub fn log_raw(level: i32, tag: &str, message: &str) -> Result<()> {
+    let tag = std::ffi::CString::new(tag)?;
+    let message = std::ffi::CString::new(message)?;
+    unsafe {
+        __android_log_print(level as i32, tag.as_ptr(), message.as_ptr());
+    }
+    Ok(())
+}
+
+pub fn get_property(name: &str) -> Result<String> {
+    let name = std::ffi::CString::new(name)?;
+    let mut buf = vec![0u8; 92];
+    unsafe {
+        __system_property_get(name.as_ptr(), buf.as_mut_ptr() as *mut c_char);
+    }
+    Ok(String::from_utf8(buf)?)
+}
+
 pub fn set_property(name: &str, value: &str) -> Result<()> {
     Command::new("resetprop")
         .arg(name)
@@ -113,3 +132,8 @@ pub fn abstract_namespace_socket(name: &str) -> Result<UnixListener> {
     let listener = unsafe { UnixListener::from_raw_fd(socket) };
     Ok(listener)
 }
+
+extern "C" {
+    fn __android_log_print(prio: i32, tag: *const c_char, fmt: *const c_char, ...) -> i32;
+    fn __system_property_get(name: *const c_char, value: *mut c_char) -> u32;
+}

zygiskd/src/watchdog.rs

@@ -25,7 +25,7 @@ pub fn entry() -> Result<()> {
     if check_and_set_hint()? == false {
         log::warn!("Requirements not met, exiting");
         utils::set_property(constants::PROP_NATIVE_BRIDGE, &utils::get_native_bridge())?;
-        return Ok(())
+        return Ok(());
     }
     let end = spawn_daemon();
     set_prop_hint(constants::STATUS_CRASHED)?;
@@ -64,10 +64,21 @@ fn ensure_single_instance() -> Result<()> {
 }
 
 fn mount_prop() -> Result<()> {
-    let module_prop = fs::File::open(constants::PATH_MODULE_PROP)?;
+    let module_prop = if let root_impl::RootImpl::Magisk = root_impl::get_impl() {
+        let magisk_path = Command::new("magisk").arg("--path").output()?;
+        let mut magisk_path = String::from_utf8(magisk_path.stdout)?;
+        magisk_path.pop(); // Removing '\n'
+        let cwd = std::env::current_dir()?;
+        let dir = cwd.file_name().unwrap().to_string_lossy();
+        format!("{magisk_path}/.magisk/modules/{dir}/{}", constants::PATH_MODULE_PROP)
+    } else {
+        constants::PATH_MODULE_PROP.to_string()
+    };
+    log::info!("Mount {module_prop}");
+    let module_prop_file = fs::File::open(&module_prop)?;
     let mut section = 0;
     let mut sections: [String; 2] = [String::new(), String::new()];
-    let lines = io::BufReader::new(module_prop).lines();
+    let lines = io::BufReader::new(module_prop_file).lines();
     for line in lines {
         let line = line?;
         if line.starts_with("description=") {
@@ -83,21 +94,13 @@ fn mount_prop() -> Result<()> {
     let _ = PROP_SECTIONS.set(sections);
 
     fs::create_dir(constants::PATH_TMP_DIR)?;
+    fs::File::create(constants::PATH_TMP_PROP)?;
 
     // FIXME: sys_mount cannot be compiled on 32 bit
     unsafe {
-        let r = libc::mount(
-            CString::new("tmpfs")?.as_ptr(),
-            CString::new(constants::PATH_TMP_DIR)?.as_ptr(),
-            CString::new("tmpfs")?.as_ptr(),
-            0,
-            CString::new("mode=755")?.as_ptr() as *const libc::c_void,
-        );
-        Errno::result(r)?;
-        let _file = fs::File::create(constants::PATH_TMP_PROP)?;
         let r = libc::mount(
             CString::new(constants::PATH_TMP_PROP)?.as_ptr(),
-            CString::new(constants::PATH_MODULE_PROP)?.as_ptr(),
+            CString::new(module_prop)?.as_ptr(),
             std::ptr::null(),
             libc::MS_BIND,
             std::ptr::null(),

zygiskd/src/zygiskd.rs

@@ -10,7 +10,6 @@ use nix::{
 use passfd::FdPassingExt;
 use std::sync::{Arc, Mutex};
 use std::thread;
-use std::ffi::c_char;
 use std::fs;
 use std::os::unix::{
     net::{UnixListener, UnixStream},
@@ -64,8 +63,7 @@ pub fn entry() -> Result<()> {
 }
 
 fn get_arch() -> Result<&'static str> {
-    let output = Command::new("getprop").arg("ro.product.cpu.abi").output()?;
-    let system_arch = String::from_utf8(output.stdout)?;
+    let system_arch = utils::get_property("ro.product.cpu.abi")?;
     if system_arch.contains("arm") {
         return Ok(lp_select!("armeabi-v7a", "arm64-v8a"));
     }
@@ -181,12 +179,8 @@ fn handle_daemon_action(mut stream: UnixStream, context: &Context) -> Result<()>
                     Err(_) => break,
                 };
                 let tag = stream.read_string()?;
-                let tag = std::ffi::CString::new(tag)?;
                 let message = stream.read_string()?;
-                let message = std::ffi::CString::new(message)?;
-                unsafe {
-                    __android_log_print(level as i32, tag.as_ptr(), message.as_ptr());
-                }
+                utils::log_raw(level as i32, &tag, &message)?;
             }
         }
         DaemonSocketAction::ReadNativeBridge => {
@@ -244,7 +238,3 @@ fn handle_daemon_action(mut stream: UnixStream, context: &Context) -> Result<()>
     }
     Ok(())
 }
-
-extern "C" {
-    fn __android_log_print(prio: i32, tag: *const c_char, fmt: *const c_char, ...) -> i32;
-}